| 1. |
- Abbaspour Asadollah, Sara
(författare)
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Concurrency Bugs : Characterization, Debugging and Runtime Verification
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Concurrent software has been increasingly adopted in recent years, mainly due to the introduction of multicore platforms. However, concurrency bugs are still difficult to test and debug due to their complex interactions involving multiple threads (or tasks). Typically, real world concurrent software has huge state spaces. Thus, testing techniques and handling of concurrency bugs need to focus on exposing the bugs in this large space. However, existing solutions typically do not provide debugging information to developers (and testers) for understanding the bugs.Our work focuses on improving concurrent software reliability via three contributions: 1) An investigation of concurrent software challenges with the aim to help developers (and testers) to better understand concurrency bugs. We propose a classification of concurrency bugs and discuss observable properties of each type of bug. In addition, we identify a number of gaps in the body of knowledge on concurrent software bugs and their debugging. 2) Exploring concurrency related bugs in real-world software with respect to the reproducibility of bugs, severity of their consequence and effort required to fix them. Our findings here is that concurrency bugs are different from other bugs in terms of their fixing time and severity, while they are similar in terms of reproducibility. 3) A model for monitoring concurrency bugs and the implementation and evaluation of a related runtime verification tool to detect the bugs. In general, runtime verification techniques are used to (a) dynamically verify that the observed behaviour matches specified properties and (b) explicitly recognize understandable behaviors in the considered software. Our implemented tool is used to detect concurrency bugs in embedded software and is in its current form tailored for the FreeRTOS operating system. It helps developers and testers to automatically identify concurrency bugs and subsequently helps to reduce their finding and fixing time.
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| 2. |
- Abbaspour, Sara, 1984-
(författare)
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Electromyogram Signal Enhancement and Upper-Limb Myoelectric Pattern Recognition
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Losing a limb causes difficulties in our daily life. To regain the ability to live an independent life, artificial limbs have been developed. Hand prostheses belong to a group of artificial limbs that can be controlled by the user through the activity of the remnant muscles above the amputation. Electromyogram (EMG) is one of the sources that can be used for control methods for hand prostheses. Surface EMGs are powerful, non-invasive tools that provide information about neuromuscular activity of the subjected muscle, which has been essential to its use as a source of control for prosthetic limbs. However, the complexity of this signal introduces a big challenge to its applications. EMG pattern recognition to decode different limb movements is an important advancement regarding the control of powered prostheses. It has the potential to enable the control of powered prostheses using the generated EMG by muscular contractions as an input. However, its use has yet to be transitioned into wide clinical use. Different algorithms have been developed in state of the art to decode different movements; however, the challenge still lies in different stages of a successful hand gesture recognition and improvements in these areas could potentially increase the functionality of powered prostheses. This thesis firstly focuses on improving the EMG signal’s quality by proposing novel and advanced filtering techniques. Four efficient approaches (adaptive neuro-fuzzy inference system-wavelet, artificial neural network-wavelet, adaptive subtraction and automated independent component analysis-wavelet) are proposed to improve the filtering process of surface EMG signals and effectively eliminate ECG interferences. Then, the offline performance of different EMG-based recognition algorithms for classifying different hand movements are evaluated with the aim of obtaining new myoelectric control configurations that improves the recognition stage. Afterwards, to gain proper insight on the implementation of myoelectric pattern recognition, a wide range of myoelectric pattern recognition algorithms are investigated in real time. The experimental result on 15 healthy volunteers suggests that linear discriminant analysis (LDA) and maximum likelihood estimation (MLE) outperform other classifiers. The real-time investigation illustrates that in addition to the LDA and MLE, multilayer perceptron also outperforms the other algorithms when compared using classification accuracy and completion rate.
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| 3. |
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| 4. |
- Abola, Benard
(författare)
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Perturbed Markov Chains with Damping Component and Information Networks
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis brings together three thematic topics, PageRank of evolving tree graphs, stopping criteria for ranks and perturbed Markov chains with damping component. The commonality in these topics is their focus on ranking problems in information networks. In the fields of science and engineering, information networks are interesting from both practical and theoretical perspectives. The fascinating property of networks is their applicability in analysing broad spectrum of problems and well established mathematical objects. One of the most common algorithms in networks' analysis is PageRank. It was developed for web pages’ ranking and now serves as a tool for identifying important vertices as well as studying characteristics of real-world systems in several areas of applications. Despite numerous successes of the algorithm in real life, the analysis of information networks is still challenging. Specifically, when the system experiences changes in vertices /edges or it is not strongly connected or when a damping stochastic matrix and a damping factor are added to an information matrix. For these reasons, extending existing or developing methods to understand such complex networks is necessary.Chapter 2 of this thesis focuses on information networks with no bidirectional interaction. They are commonly encountered in ecological systems, number theory and security systems. We consider certain specific changes in a network and describe how the corresponding information matrix can be updated as well as PageRank scores. Specifically, we consider the graph partitioned into levels of vertices and describe how PageRank is updated as the network evolves.In Chapter 3, we review different stopping criteria used in solving a linear system of equations and investigate each stopping criterion against some classical iterative methods. Also, we explore whether clustering algorithms may be used as stopping criteria.Chapter 4 focuses on perturbed Markov chains commonly used for the description of information networks. In such models, the transition matrix of an information Markov chain is usually regularised and approximated by a stochastic (Google type) matrix. Stationary distribution of the stochastic matrix is equivalent to PageRank, which is very important for ranking of vertices in information networks. Determining stationary probabilities and related characteristics of singularly perturbed Markov chains is complicated; leave alone the choice of regularisation parameter. We use the procedure of artificial regeneration for the perturbed Markov chain with the matrix of transition probabilities and coupling methods. We obtain ergodic theorems, in the form of asymptotic relations. We also derive explicit upper bounds for the rate of convergence in ergodic relations. Finally, we illustrate these results with numerical examples.
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| 5. |
- Abrahamsson, Henrik
(författare)
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Network overload avoidance by traffic engineering and content caching
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Internet traffic volume continues to grow at a great rate, now driven by video and TV distribution. For network operators it is important to avoid congestion in the network, and to meet service level agreements with their customers. This thesis presents work on two methods operators can use to reduce links loads in their networks: traffic engineering and content caching.This thesis studies access patterns for TV and video and the potential for caching. The investigation is done both using simulation and by analysis of logs from a large TV-on-Demand system over four months.The results show that there is a small set of programs that account for a large fraction of the requests and that a comparatively small local cache can be used to significantly reduce the peak link loads during prime time. The investigation also demonstrates how the popularity of programs changes over time and shows that the access pattern in a TV-on-Demand system very much depends on the content type.For traffic engineering the objective is to avoid congestion in the network and to make better use of available resources by adapting the routing to the current traffic situation. The main challenge for traffic engineering in IP networks is to cope with the dynamics of Internet traffic demands.This thesis proposes L-balanced routings that route the traffic on the shortest paths possible but make sure that no link is utilised to more than a given level L. L-balanced routing gives efficient routing of traffic and controlled spare capacity to handle unpredictable changes in traffic. We present an L-balanced routing algorithm and a heuristic search method for finding L-balanced weight settings for the legacy routing protocols OSPF and IS-IS. We show that the search and the resulting weight settings work well in real network scenarios.
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| 6. |
- Afshar, Sara
(författare)
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Lock-Based Resource Sharing for Real-Time Multiprocessors
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Embedded systems are widely used in the industry and are typically resource constrained, i.e., resources such as processors, I/O devices, shared buffers or shared memory might be limited in the system. Hence, techniques that can enable an efficient usage of processor bandwidths in such systems are of great importance. Locked-based resource sharing protocols are proposed as a solution to overcome resource limitation by allowing the available resources in the system to be safely shared. In recent years, due to a dramatic enhancement in the functionality of systems, a shift from single-core processors to multi-core processors has become inevitable from an industrial perspective to tackle the raised challenges due to increased system complexity. However, the resource sharing protocols are not fully mature for multi-core processors. The two classical multi-core processor resource sharing protocols, spin-based and suspension-based protocols, although providing mutually exclusive access to resources, can introduce long blocking delays to tasks, which may be unacceptable for many industrial applications. In this thesis we enhance the performance of resource sharing protocols for partitioned scheduling, which is the de-facto scheduling standard for industrial real-time multi-core processor systems such as in AUTOSAR, in terms of timing and memory requirements. A new scheduling approach uses a resource efficient hybrid approach combining both partitioned and global scheduling where the partitioned scheduling is used to schedule the major number of tasks in the system. In such a scheduling approach applications with critical task sets use partitioned scheduling to achieve higher level of predictability. Then the unused bandwidth on each core that is remained from partitioning is used to schedule less critical task sets using global scheduling to achieve higher system utilization. These scheduling schema however lacks a proper resource sharing protocol since the existing protocols designed for partitioned and global scheduling cannot be directly applied due to the complex hybrid structure of these scheduling frameworks. In this thesis we propose a resource sharing solution for such a complex structure. Further, we provide the blocking bounds incurred to tasks under the proposed protocols and enhance the schedulability analysis, which is an essential requirement for real-time systems, with the provided blocking bounds.
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| 7. |
- Ahlberg, Carl
(författare)
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Embedded high-resolution stereo-vision of high frame-rate and low latency through FPGA-acceleration
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Autonomous agents rely on information from the surrounding environment to act upon. In the array of sensors available, the image sensor is perhaps the most versatile, allowing for detection of colour, size, shape, and depth. For the latter, in a dynamic environment, assuming no a priori knowledge, stereo vision is a commonly adopted technique. How to interpret images, and extract relevant information, is referred to as computer vision. Computer vision, and specifically stereo-vision algorithms, are complex and computationally expensive, already considering a single stereo pair, with results that are, in terms of accuracy, qualitatively difficult to compare. Adding to the challenge is a continuous stream of images, of a high frame rate, and the race of ever increasing image resolutions. In the context of autonomous agents, considerations regarding real-time requirements, embedded/resource limited processing platforms, power consumption, and physical size, further add up to an unarguably challenging problem.This thesis aims to achieve embedded high-resolution stereo-vision of high frame-rate and low latency, by approaching the problem from two different angles, hardware and algorithmic development, in a symbiotic relationship. The first contributions of the thesis are the GIMME and GIMME2 embedded vision platforms, which offer hardware accelerated processing through FGPAs, specifically targeting stereo vision, contrary to available COTS systems at the time. The second contribution, toward stereo vision algorithms, is twofold. Firstly, the problem of scalability and the associated disparity range is addressed by proposing a segment-based stereo algorithm. In segment space, matching is independent of image scale, and similarly, disparity range is measured in terms of segments, indicating relatively few hypotheses to cover the entire range of the scene. Secondly, more in line with the conventional stereo correspondence for FPGAs, the Census Transform (CT) has been identified as a recurring cost metric. This thesis proposes an optimisation of the CT through a Genetic Algorithm (GA) - the Genetic Algorithm Census Transform (GACT). The GACT shows promising results for benchmark datasets, compared to established CT methods, while being resource efficient.
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| 8. |
- Ahlskog, Mats, 1970-
(författare)
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The fuzzy front end of manufacturing technology development : Exploring the link between the known and the unknown
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is well known that a way of competing on a global market is through the introduction of new manufacturing technologies in the production system that can improve product quality as well as contribute to reducing manufacturing time, reduced product price and in the end increased profits. Manufacturing companies that develop and introduce new manufacturing technologies can differentiate themselves from others and thus achieve increased competitiveness.The fuzzy front end of manufacturing technology development is characterized by a high degree of technology uncertainty and challenges due to the lack of access to relevant knowledge, lack of a structured development process, and enough resources that are working with development of new manufacturing technologies.In the literature only a few empirical studies that explore the fuzzy front end of manufacturing technology development can be found. Prior research highlights that little is actually known about what should be done in the fuzzy front end of manufacturing technology development projects, and thus more research is needed. Supporting the fuzzy front end of manufacturing technology development is important to facilitate a successful introduction of new manufacturing technologies, fast time-to-volume and long-term production system development.Based on the above-mentioned importance of developing new manufacturing technology, the objective of the research presented in this thesis is to explore the fuzzy front end of manufacturing technology development. In order to fulfil the objective, empirical data were collected from five case studies conducted in the manufacturing industry. During the empirical studies four important parts were studied: organising, knowledge development, collaboration and the development process.The main findings revealed that development of new manufacturing technology is often conducted in collaboration with external partners and many ad hoc decisions are taken due to lack of a predefined development process for the fuzzy front end of manufacturing technology development. In addition, in the fuzzy front end access to relevant manufacturing knowledge is important and knowledge needs to be developed in order to reduce technology uncertainty.In order to support the fuzzy front end of manufacturing technology development projects, a supporting framework has been developed. The proposed framework is an elaboration of results from the research questions addressed and can be used as a guideline to overcome the challenges observed in the fuzzy front end of manufacturing technology development projects. The framework is built on two important dimensions for innovations, degree of technology uncertainty and degree of novelty. The critical factors identified in the analysis are embedded in the proposed framework as central parts in the fuzzy front end of manufacturing technology development.
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| 9. |
- Ahmed, Mobyen Uddin, 1976-
(författare)
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A Multimodal Approach for Clinical Diagnosis and Treatment
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A computer-aided Clinical Decision Support System (CDSS) for diagnosis and treatment often plays a vital role and brings essential benefits for clinicians. Such a CDSS could function as an expert for a less experienced clinician or as a second option/opinion of an experienced clinician to their decision making task. Nevertheless, it has been a real challenge to design and develop such a functional system where accuracy of the system performance is an important issue. This research work focuses on development of intelligent CDSS based on a multimodal approach for diagnosis, classification and treatment in medical domains i.e. stress and post-operative pain management domains. Several Artificial Intelligence (AI) techniques such as Case-Based Reasoning (CBR), textual Information Retrieval (IR), Rule-Based Reasoning (RBR), Fuzzy Logic and clustering approaches have been investigated in this thesis work. Patient’s data i.e. their stress and pain related information are collected from complex data sources for instance, finger temperature measurements through sensor signals, pain measurements using a Numerical Visual Analogue Scale (NVAS), patient’s information from text and multiple choice questionnaires. The proposed approach considers multimedia data management to be able to use them in CDSSs for both the domains. The functionalities and performance of the systems have been evaluated based on close collaboration with experts and clinicians of the domains. In stress management, 68 measurements from 46 subjects and 1572 patients’ cases out of ≈4000 in post-operative pain have been used to design, develop and validate the systems. In the stress management domain, besides the 68 measurement cases, three trainees and one senior clinician also have been involved in order to conduct the experimental work. The result from the evaluation shows that the system reaches a level of performance close to the expert and better than the senior and trainee clinicians. Thus, the proposed CDSS could be used as an expert for a less experienced clinician (i.e. trainee) or as a second option/opinion for an experienced clinician (i.e. senior) to their decision making process in stress management. In post-operative pain treatment, the CDSS retrieves and presents most similar cases (e.g. both rare and regular) with their outcomes to assist physicians. Moreover, an automatic approach is presented in order to identify rare cases and 18% of cases from the whole cases library i.e. 276 out of 1572 are identified as rare cases by the approach. Again, among the rare cases (i.e. 276), around 57.25% of the cases are classified as ‘unusually bad’ i.e. the average pain outcome value is greater or equal to 5 on the NVAS scale 0 to 10. Identification of rear cases is an important part of the PAIN OUT project and can be used to improve the quality of individual pain treatment.
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| 10. |
- Akan, Batu, 1981-
(författare)
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Planning and Sequencing Through Multimodal Interaction for Robot Programming
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Over the past few decades the use of industrial robots has increased the efficiency as well as the competitiveness of several sectors. Despite this fact, in many cases robot automation investments are considered to be technically challenging. In addition, for most small and medium-sized enterprises (SMEs) this process is associated with high costs. Due to their continuously changing product lines, reprogramming costs are likely to exceed installation costs by a large margin. Furthermore, traditional programming methods of industrial robots are too complex for most technicians or manufacturing engineers, and thus assistance from a robot programming expert is often needed. The hypothesis is that in order to make the use of industrial robots more common within the SME sector, the robots should be reprogrammable by technicians or manufacturing engineers rather than robot programming experts. In this thesis, a novel system for task-level programming is proposed. The user interacts with an industrial robot by giving instructions in a structured natural language and by selecting objects through an augmented reality interface. The proposed system consists of two parts: (i) a multimodal framework that provides a natural language interface for the user to interact in which the framework performs modality fusion and semantic analysis, (ii) a symbolic planner, POPStar, to create a time-efficient plan based on the user's instructions. The ultimate goal of this work in this thesis is to bring robot programming to a stage where it is as easy as working together with a colleague.This thesis mainly addresses two issues. The first issue is a general framework for designing and developing multimodal interfaces. The general framework proposed in this thesis is designed to perform natural language understanding, multimodal integration and semantic analysis with an incremental pipeline. The framework also includes a novel multimodal grammar language, which is used for multimodal presentation and semantic meaning generation. Such a framework helps us to make interaction with a robot easier and more natural. The proposed language architecture makes it possible to manipulate, pick or place objects in a scene through high-level commands. Interaction with simple voice commands and gestures enables the manufacturing engineer to focus on the task itself, rather than the programming issues of the robot. The second issue addressed is due to inherent characteristics of communication with the use of natural language; instructions given by a user are often vague and may require other actions to be taken before the conditions for applying the user's instructions are met. In order to solve this problem a symbolic planner, POPStar, based on a partial order planner (POP) is proposed. The system takes landmarks extracted from user instructions as input, and creates a sequence of actions to operate the robotic cell with minimal makespan. The proposed planner takes advantage of the partial order capabilities of POP to execute actions in parallel and employs a best-first search algorithm to seek the series of actions that lead to a minimal makespan. The proposed planner can also handle robots with multiple grippers, parallel machines as well as scheduling for multiple product types.
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| 11. |
- Akbari, Keramatollah, 1961-
(författare)
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Simulation of Indoor Radon and Energy Recovery Ventilation Systems in Residential Buildings
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study aims to investigate the effects of ventilation rate, indoor air temperature, humidity and using a heat recovery ventilation system on indoor radon concentration and distribution.Methods employed include energy dynamic and computational fluid dynamics simulation, experimental measurement and analytical investigations. Experimental investigations primarily utilize a continuous radon meter and a detached house equipped with a recovery heat exchanger unit.The results of the dynamic simulation show that the heat recovery unit is cost-effective for the cold Swedish climate and an energy saving of about 30 kWh per floor area per year is possible, while it can be also used to lower radon level.The numerical results showed that ventilation rate and ventilation location have significant impacts on both radon content and distribution, whereas indoor air temperature only has a small effect on radon level and distribution and humidity has no impact on radon level but has a small impact on its distribution.
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| 12. |
- Albuhayri, Mohammed
(författare)
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Asymptotics of implied volatility in the Gatheral double stochastic volatility model
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We consider a market model of financial engineering with three factors represented by three correlated Brownian motions. The volatility of the risky asset in this model is the sum of two stochastic volatilities. The dynamic of each volatility is governed by a mean-reverting process. The first stochastic volatility of mean-reversion process reverts to the second volatility at a fast rate, while the second volatility moves slowly to a constant level over time with the state of the economy.The double mean-reverting model by Gatheral (2008) is motivated by empirical dynamics of the variance of the stock price. This model can be consistently calibrated to both the SPX options and the VIX options. However due to the lack of an explicit formula for both the European option price and the implied volatility, the calibration is usually done using time consuming methods like Monte Carlo simulation or the finite difference method.To solve the above issue, we use the method of asymptotic expansion developed by Pagliarani and Pascucci (2017). In paper A, we study the behaviour of the implied volatility with respect to the logarithmic strike price and maturity near expiry and at-the-money. We calculate explicitly the asymptotic expansions of implied volatility within a parabolic region up the second order. In paper B we improve the results obtain in paper A by calculating the asymptotic expansion of implied volatility under the Gatheral model up to order three. In paper C, we perform numerical studies on the asymptotic expansion up to the second order. The Monte-Carlo simulation is used as the benchmark value to check the accuracy of the expansions. We also proposed a partial calibration procedure using the expansions. The calibration procedure is implemented on real market data of daily implied volatility surfaces for an underlying market index and an underlying equity stock for periods both before and during the COVID-19 crisis. Finally, in paper D we check the performance of the third order expansion and compare it with the previous results.
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| 13. |
- Alshaibi, Alsedieg
(författare)
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Business Relationships Between Local Firms and MNCs in a less Developing Country : The Case of Libyan Firms
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- International business relationships have been widely researched over the last three decades. Themajor attention of these studies, no matter what their theoretical perspective, concerns the MNCs inthe less developing countries (LDCs). Studies that illustrate how firms in LDCs behave regardinginteraction with MNCs are slim. Therefore, this study focuses on firms in LDCs, namely Libyan firms,and their relationships with MNCs. The study reflects not only on the relationships between the localfirms with MNCs but also the impacts of other interrelated business and non-business units on theserelationships. The study employs business network theory for industrial marketing and develops amodel applicable for studying such a market.The empirical study employs a survey method which examines 60 Libyan firms’ relationships withforeign suppliers containing more than 300 questions. In the empirical part, the study shows that therelationships like technological adaptation, technological cooperation and information exchange wereawarded low values. The measures on the other hand show a high value of impact from the politicalactors and even activities in the contextual environment. The study shows in detail where and howthe political actions influence business relationships. These impacts from the local environment affectlocal firms more than the foreign suppliers, and thus have some bearing on the MNCs and local firms’relationship weaknesses and strengths.The thesis’ conceptual contribution stands on development of new notions in business network theoryby integration of the contextual environment, in other words, network environment, and examinationof their impact on the strength of the focal business relationship. The study further contributesknowledge, not only for firms and politicians in LDCs to understand the consequence of their actions,but also provides deep information for MNCs to understand issues like why firms in LDCs behave ina specific way. Such understandings facilitate the development of cooperation. The study providesinformation about a number of characteristics which are specific for the business networks of such amarket which is dependent on only one resource like oil. While most studies in the field ofinternational business regard the business activities of MNCs, more research is needed to also observethe behaviour of firms from LDCs to gain deeper knowledge on the relationship between the MNCsand local firms from LDCs. The role of political actors and the influence of dependency on one soletype of resources and aspects like change in the prices of this resource seem to be important, but arequite neglected in research in international business.
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| 14. |
- Anastasiadou, Elena
(författare)
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Business Actor Engagement : Understanding Collaborative Business Initiative Outcomes
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Business and service literature has recognized engagement as a crucial concept that influences the success of business initiatives beyond core transactions. Engagement involves various actors’ contributions like time, knowledge, and other resources that extend beyond contractual obligations. Engagement was initially studied in business-to-consumer (B2C) contexts, where its activities include word-of-mouth feedback and co-creating value propositions. As engagement research extended into business-to-business (B2B) contexts, engagement activities included customer referencing and participation in service development, with contributions like influence, time, and expertise. This thesis focuses on understanding engagement in B2B contexts – conceptualized as business actor engagement (BAE) – and offers practice-relevant midrange theory conceptualizations of collaboration in business initiatives beyond the contracted and regular transactions. The study employs a qualitative approach to studying Swedish real estate landlords and their efforts to involve commercial tenants in collaborative business initiatives (conceptualized as engagement initiatives) to deepen the understanding of BAE. The collaborative business initiatives in the thesis’ empirical setting address issues of environmental sustainability, such as reducing greenhouse gas emissions and improving energy efficiency. Despite providers using similar strategies to involve their B2B customers, the outcomes of these engagement initiatives vary, often due to hidden aspects affecting customers’ engagement. The findings are presented in four papers that offer insights on BAE such as how prerequisite factors, antecedents and manifestations impact customers’ BAE and consequently the outcomes of collaborative business initiatives. By exploring BAE, the study offers an understanding of the variety in outcomes from collaborative business initiatives, i.e., why some business initiatives succeed or fail. By understanding and managing BAE aspects, the study suggests collaborative business initiatives may result in achieving intended outcomes, such as goals related to addressing climate change and societal problems. Although the study centers on the real estate industry, the findings have broader implications for businesses striving to develop and adopt initiatives that will require their partners’ engagement to achieve intended outcomes and – by doing so – build strong, lasting relationships with their partners.
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| 15. |
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| 16. |
- Andersson, Anna Karin
(författare)
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Everyday functioning in six year-old children born preterm : From a child perspective towards the child's perspective
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of the thesis was to explore everyday functioning in six year-old children born preterm, from the children’s perspectives and from their parents’ perspectives. The relation between everyday functioning and neonatal risk factors, behavioural characteristics was studied with descriptive and correlational statistics, ANOVA and multiple linear regression (I). Patterns of everyday functioning were explored in a cluster analysis following a person-oriented approach (II). In a mixed method approach, the children’s and their parents’ perceptions on children’s competence in everyday activities were explored with a pictorial instrument and analysed with descriptive statistics and qualitative content analysis (III). The children’s perceptions of meaningful everyday life situations were explored in a photo voice study, analysed with qualitative content analysis. In total, 144 children born preterm and 222 children born at term and their parents were involved.The results indicated that from the parents’ perspective most children born preterm and full-term were perceived with strong everyday functioning featuring strong motor, process and communication skills, a positive interaction pattern and low levels of behaviour problems. As a group, the children born very preterm were perceived weaker in their everyday functioning than the full-term group but the pattern of performance skills, interaction and behaviour varied similar to that of children born full-term. Further, it was found that preterm birth was not the main predictor, instead hyperactivity had most influence on everyday functioning. Moreover, the children born preterm perceived themselves to be overall strong performers of everyday activities. They wanted to be active and do things and for that they wanted to have skills and significant others i.e. siblings, parents, friends and pets to interact with and to feel safe and loved. Further, the children born preterm expressed a will to develop, improve and gain new skills and to have more opportunities to do meaningful things.In conclusion, the results in this thesis indicate that young children born preterm are able to reflect on their everyday functioning, and express needs and desires for their participation in meaningful everyday life situations. Moreover, preterm birth is not the sole predictor of everyday functioning more critical is the interaction of individual, behavioural and contextual factors.
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| 17. |
- Andersson, Anna-Lena
(författare)
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Utbildningssituationen för elever med lindrig intellektuell funktionsnedsättning : Lärares och föräldrars perspektiv
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The goal of the Swedish educational system is to offer all students a meaningful and equal education in an inclusive classroom environment. At the same time there are parallel school systems in Sweden, comprised by the Compulsory School for Students with Intellectual Disability (CSSID) and Compulsory School (CS). Students who are not able to achieve in accordance with syllabus of CS and who have an intellectual disability (ID) are eligible to receive education according to the CSSID syllabus. The decision of placement in either type of school rests on students’ parents. It can be assumed, therefore, that teachers are expected to offer education adjusted to each student’s individual needs.The aim of the thesis is to deepen the knowledge about the educational situation of students with mild intellectual disability (MID) through the perspectives of teachers and parents. Teachers’ and parents’ experiences and perceptions are studied: parents offer their stories about their children’s educational situation over time, and teachers’ reason about their work in teaching situations with the target group. Furthermore, pedagogical evaluations are studied to look at how school difficulties in teaching situations are described.The empirical data was collected in one municipality from the middle part of Sweden. The data constitutes of six interviews with parents of students with MID, and also 21 pedagogical evaluations of students with MID. Additionally, interviews were conducted with 21 teachers: eleven CS teachers and ten CSSID teachers.All interviews were analyzed using thematic analysis and using Interpretative Phenomenological Analysis (IPA), and manifest contents analysis was used to analyze pedagogical evaluations. Theories used were Biesta’s theory on the dimensions of education, the three levels in education transitions by Griebel and Niesel, and the school didactic theory by Uljen.The results show that the educational transitions and the educational situation around students with MID are complex. The transition from CS to CSSID means a readjustment for parents and they express the need for support from professionals in these transitions. Pedagogical evaluations contain individual-focused descriptions and focus to a lesser extent on teaching adaptations. Teachers in CS and CSSID outlined both common challenges in provision of support to all students but also described different prerequisites for it in the two school types. The results indicate that the teaching situation in both CSSID and the CS needs to be reviewed with regard to the school's organizational conditions to offer inclusive education.Keywordsinclusive education, transition, students with mild intellectual disability, interview, pedagogical evaluations, teachers, parents
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| 18. |
- Andersson, Carina, 1970-
(författare)
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Informationsdesign i tillståndsövervakning : En studie av ett bildskärmsbaserat användargränssnitt för tillståndsövervakning och tillståndsbaserat underhåll
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This research concerns the information design and visual design of graphical user interfaces (GUI) in the condition monitoring and condition-based maintenance (CBM) of production equipment. It also concerns various communicative aspects of a GUI, which is used to monitor the condition of assets. It applies to one Swedish vendor and its intentions to design information. In addition, it applies to the interaction between the GUI and its individual visual elements, as well as the communication between the GUI and the users (in four Swedish paper mills).The research is performed as a single case study. Interviews and observations have been the main methods for data collection. Empirical data is analyzed with methods inferred to semiotics, rhetoric and narratology. Theories in information science and regarding remediation are used to interpret the user interface design.The key conclusion is that there are no less than five different forms of information, all important when determining the conditions of assets. These information forms include the words, images and shapes in the GUI, the machine components and peripherals equipment, the information that takes form when personnel communicate machine conditions, the personnel’s subjective associations, and the information forms that relate to the personnel's actions and interactions.Preventive technicians interpret the GUI-information individually and collectively in relation to these information forms, which influence their interpretation and understanding of the GUI information. Social media in the GUI makes it possible to represent essential information that takes form when employees communicate a machine’s condition. Photographs may represent information forms as a machine’s components, peripherals, and local environment change over time. Moreover, preventative technicians may use diagrams and photographs in the GUI to change attitudes among the personnel at the mills and convince them, for example, of a machine’s condition or the effectiveness of CBM as maintenance policy.
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| 19. |
- Appelgren Engström, Heléne, 1968-
(författare)
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Family formation in two-mother families : Experiences of parental support in antenatal and child health care in Sweden
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim with the thesis was to examine same-sex mothers experiences of forming a family, pregnancy, parenthood and parental support from professionals in antenatal and child health care. An additional purpose was to explore professionals' experiences of meeting and supporting families with two mothers.The results are based on four articles (three studies). The project started with exploratory semi-structured interviews (n = 20) with mothers in same-sex relationships who had children with the help of assisted reproduction at a Swedish clinic. Thereafter, a web survey was designed based on the results from the first sub-study. The survey, as well as a survey on perceived parenting stress (SPSQ), was answered by 146 mothers in same-sex relationships. Finally, focus groups were held with professionals (n = 13) in antenatal and child health care with experience of meeting and supporting families with two mothers.The results showed that the mothers in same-sex relationships experienced the process of forming a family as a stressful journey in a heteronormative world, and that they lacked psychological / emotional support (Articles I, III). The results also showed that the mothers strived for equal parenthood and that they lacked professional support (Articles II, III).Furthermore, the results showed that the non-birth mother experienced a lower degree of acknowledgement from antenatal and child health care than the mother who gave birth, and a lower degree of support from antenatal care but no difference in the experience of support from child health care. The mothers also experienced a low degree of parenting stress (Article III).Professionals strived for an open approach in meeting new parents. They met well-prepared mothers who planned for equal parenting. Professionals expressed that they either gave equal support to all parents, or that they provided tailored support to same-sex mothers (Article IV).The thesis contributes with an in-depth understanding and increased knowledge about mothers in same-sex relationships' experience of family formation as well as their experience of treatment and support from professionals in antenatal and child health care. Furthermore, it also shows professionals' experiences of meeting and supporting families with two mothers.
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| 20. |
- Aranda Muñoz, Álvaro
(författare)
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Collaborative Thinking with and through Technology : Materials, methods and perspectives
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The rapid development and integration of IoT, AI, and digital twin technologies into work environments create new demands and challenges for organisations, including the need to upskill and prepare their workforces for new technological applications and capabilities. The collaborative design tradition draws upon participatory notions of joint inquiry to help people in the ideation and conception of alternative futures; however, given the novelty and the rapidity of the technological transformations, there is an opportunity to engage people unfamiliar with technology and design in the ideation and conceptualisation of work-oriented improvements using these technologies.This dissertation investigates what dimensions are necessary to support participatory processes for identifying and creating work-oriented improvements with technology and how design practitioners can apply these dimensions to stage these joint inquiry situations. To achieve these aims, explorations of and reflections on design are guided by a research-through-design approach that builds on three collaborative design cases that address real-world situations in a variety of contexts and participants: the joint inquiry processes of factory workers in the ideation, conceptualisation and prototyping of IoT work-oriented improvements; the joint inquiry process of ideation and conceptualisation of a digital twin in a manufacturing environment; and the joint inquiry processes of workers (predominantly from the healthcare sector) in ideating, conceptualising, and prototyping roles, skills, and products relying on IoT and AI technologies for their work futures. The research and design practice is guided by Deweyan pragmatism, underscoring the role and nature of materials (design methods, tools, and practices) in participatory design processes. Drawing from the three collaborative design cases and these theoretical notions, this thesis addresses two research questions: “What dimensions are needed to support participants in creating work-oriented improvements using technology?” and “How can these dimensions inform designers in staging joint inquiry situations of work-oriented improvements using technology?” The research methods consist of audio-recorded interviews, field notes, and collective reflective sessions to analyse the empirical material and video recordings. The main contributions are the identification of dimensions that underscore technology and work-oriented themes in joint inquiry and the framework of “thinking with and through technology”, which integrates these dimensions into a guided reflective and analytical design process. These contributions can help design and innovation practitioners and researchers prepare and stage materials, methods, and perspectives of joint inquiry situations concerning technology. The framework presents a “thinking with” perspective that underscores the material properties of technology and what the technology can offer to participants, and a “thinking through” perspective to contest the role of technology in organisations and open the design space to consider more sustainable and responsible futures. These results contribute to the collaborative design domain by developing knowledge and new nuances when staging joint inquiry situations of work-oriented improvements with technology. New understandings of these dimensions can contribute to an organisational landscape where workers can exercise their creativity, upskill their capacities, and voice their ideas and concerns concerning the technologies being integrated into their work environments.
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| 21. |
- Arkkukangas, Marina
(författare)
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Evaluation of the Otago Exercise Programme with or without motivational interviewing : Feasibility, experiences, effects and adherence among older community-dwelling people
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Falls and injuries related to falls are one of the most common health problems among older people and are becoming increasingly more frequent. Regular exercise has been identified as one of the most effective fall-prevention activities for older people; however, awareness of the impact of exercise programmes and adherence to recommended exercise among the elderly population is generally low. Research examining how an exercise programme is administered to and experienced by elderly community-dwelling people is needed.The overall aim of this thesis was to investigate the feasibility, experiences and effects of and adherence to the fall-preventive Otago Exercise Programme (OEP) with or without motivational interviewing (MI) among community-dwelling people aged 75 years or older.Four studies were performed from October 2012 to May 2016 in a sample of 175 people. Both quantitative and qualitative research methods were used. The methods included the feasibility for conducting a randomized controlled trial (RCT) (I), individual face-to-face interviews (II), an RCT (III) and a prospective cohort study (IV). The intervention was given to two groups. The participants who received OEP with or without MI were compared with a control group that received standard care.The feasibility of performing an exercise intervention with or without MI was acceptable from the perspective of the participating physiotherapists. From the perspective of the older participants performing the exercise with behavioural change support, the inclusion of monitored exercises in everyday life and daily routines was important. The participants also expressed experiencing more strength, improved physical functioning and greater hope for an extended active life during old age.From the short-term perspective, there were significant improvements within the OEP combined with MI group in terms of physical performance, fall self-efficacy, activity level, and handgrip strength. Improved physical performance and fall self-efficacy were also found within the control group; however, corresponding differences did not occur in the OEP group without MI. There were no significant differences between the study groups after 12 weeks of regular exercise. Adherence to the exercises in the pooled exercise group was 81% at the 12-week follow-up.At the 52-week follow-up, the behavioural factors being physically active and obtaining behavioural support in terms of MI had a significant association with adherence to the exercise programme.These studies provide some support for the combination of OEP with MI as the addition of MI was valuable for achieving adherence to the exercise programme over time in older community-dwelling people.
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| 22. |
- Aslam, Mudassar, 1979-
(författare)
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Bringing Visibility in the Clouds : using Security, Transparency and Assurance Services
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The evolution of cloud computing allows the provisioning of IT resources over the Internet and promises many benefits for both - the service users and providers. Despite various benefits offered by cloud based services, many users hesitate in moving their IT systems to the cloud mainly due to many new security problems introduced by cloud environments. In fact, the characteristics of cloud computing become basis of new problems, for example, support of third party hosting introduces loss of user control on the hardware; similarly, on-demand availability requires reliance on complex and possibly insecure API interfaces; seamless scalability relies on the use of sub-providers; global access over public Internet exposes to broader attack surface; and use of shared resources for better resource utilization introduces isolation problems in a multi-tenant environment. These new security issues in addition to existing security challenges (that exist in today's classic IT environments) become major reasons for the lack of user trust in cloud based services categorized in Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) or Infrastructure-as-a-Service (IaaS).The focus of this thesis is on IaaS model which allows users to lease IT resources (e.g. computing power, memory, storage, etc.) from a public cloud to create Virtual Machine (VM) instances. The public cloud deployment model considered in this thesis exhibits most elasticity (i.e. degree of freedom to lease/release IT resources according to user demand) but is least secure as compared to private or hybrid models. As a result, public clouds are not trusted for many use cases which involve processing of security critical data such as health records, financial data, government data, etc. However, public IaaS clouds can also be made trustworthy and viable for these use cases by providing better transparency and security assurance services for the user. In this thesis, we consider such assurance services and identify security aspects which are important for making public clouds trustworthy. Based upon our findings, we propose solutions which promise to improve cloud transparency thereby realizing trustworthy clouds.The solutions presented in this thesis mainly deal with the secure life cycle management of the user VM which include protocols and their implementation for secure VM launch and migration. The VM launch and migration solutions ensure that the user VM is always hosted on correct cloud platforms which are setup according to a profile that fulfills the use case relevant security requirements. This is done by using an automated platform security audit and certification mechanism which uses trusted computing and security automation techniques in an integrated solution. In addition to provide the assurance about the cloud platforms, we also propose a solution which provides assurance about the placement of user data in correct and approved geographical locations which is critical from many legal aspects and usually an important requirement of the user. Finally, the assurance solutions provided in this thesis increase cloud transparency which is important for user trust and to realize trustworthy clouds.
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| 23. |
- Avelin, Anders, 1966-
(författare)
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Process Modeling of Combustion and Digesters for On-line Applications
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass has increased in recent years due to the efforts to reduce the high emissions of greenhouse gases, primarily carbon dioxide from combustion of fossil fuels. At the same time industrial processes have become more complex because of increased production rates and profitability requirements. A higher degree of automation is needed when the processes are too complex to be handled manually. There is a need to find modeling strategies that can automatically handle the challenges that the conversion of biomass in an industrial process entails, such as operational changes, decreasing component and overall system efficiency, drifting sensors, etc. The objective of this thesis is to develop a methodology for on-line applications in industrial processes. Dynamic process models have been developed for continuous digesters and boilers. Process models have been evaluated for their use in continuous industrial process. Applications that have been studied are monitoring and diagnostics, advanced control and decision support. The process models are designed for on-line simulations. The results shows that the use of mathematical simulation models can improve the use of both process data and process understanding, to achieve improved diagnostics, advanced control and process optimization. In the two examples of industrial processes covered in this thesis, we can see that similar types of models can be used for completely different types of processes, such as pulp digesters and boilers. It also demonstrates the ability to combine soft sensors and hard sensors with physical models to take the information to a higher level of utilization.
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| 24. |
- Axelsson, Karin, 1969-
(författare)
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Entrepreneurship in a School Setting : Introducing a Business Concept in a Public Context
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Entrepreneurship has during the last decades gained an immense interest in academia, politics and practice. It is argued from politics that more entrepreneurs are necessary for the economic development. In addition, nowadays entrepreneurship is also perceived as a solution to social and societal challenges. This drives a need for entrepreneurial people everywhere in society who can cope with the inconstant and uncertain world of today. As a consequence, there are around the world numerous educational initiatives trying to inspire and fuel an entrepreneurial mind-set. Here, educations of all kind become relevant contexts since they provide an opportunity to affect children, youth’s and adult’s interest and attitudes towards entrepreneurship, and as such give a possibility to reach a vast number of people.Sweden is no exception, and in 2009 the Swedish Government launched a ‘Strategy for entrepreneurship in the field of education’ in which entrepreneurship is said to run like a common thread throughout education. The main focus is that self-employment is to become as natural as being an employee. As such the Government took an active stand for implementing entrepreneurship in the school setting on a broad front, from preschool to adult education.This development can be seen as part of New Public Management; a development where concepts from the private sector are lent and transferred to the public sector. Thus, when introducing entrepreneurship in the Swedish educational system, this at the same time means introducing a traditional business concept in a public setting. Therefore, the overall aim of this thesis is to increase knowledge of and insights on how a business concept – entrepreneurship – is operationalised and constructed in a public setting.When placing entrepreneurship in new societal contexts other questions arise and complexity intensifies. In this qualitative research, the empirical context in focus are schools. It investigates how entrepreneurship is constructed among teachers in their work. But also how this business concept is included in a non-business setting by studying how the entrepreneurship strategy is operationalised in educational practice.As such the thesis and its findings contribute to the scientific discussions on societal entrepreneurship and entrepreneurship education, as well as on strategy and strategising in a public context. The research also aspire to serve inspiration, insights and food for thoughts on discussions and reflections on entrepreneurship within the school practice. This compilation thesis include five papers. To be able to fulfil the aim this research use a broad theoretical base and multiple qualitative research methods. The combination of methods include semi-structured interviews, in-depth interview using the stimulated recall method, focus group interviews, participative meetings, observations, document studies, digital questionnaires, written inquiries, analysing texts and critical incidents questionnaires.
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| 25. |
- Aye, Tin Nwe, 1989-
(författare)
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POPULATION DYNAMICS AND TREE GROWTH STRUCTURE IN MATHEMATICAL ECOLOGY
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on four papers related to mathematical biology, where three papers focus on population dynamics and one paper concerns tree growth and stem structure. The first two papers are mainly devoted to studying the dynamics of physiologically structured population models by using Escalator Boxcar Train (EBT) method. The third paper concerns a class of stage-structured population systems, in both deterministic and stochastic settings. The fourth paper explores how a branch thinning model can be utilized to describe the cross-sectional area of the stem of a tree, thus generalizing the classical pipe model.In Paper I, we present a merging procedure to reduce the increasing system of ordinary differential equations generated by the EBT method. In particular, we modify the EBT method to include merging of cohorts. The accuracy of this model is explored on a colony of Daphnia Pulex.In Paper II, we study the convergence rate of the modified EBT model, allowing a general class of non-linear merging procedures. We show that this modified EBT method induces a bounded number of cohorts, independent of the number of time steps. This in turn, improves the speed of the numerical algorithm for solving the population dynamics from polynomial time to linear time, that is, the time consumption to find the solution is proportional to the number of time steps.In Paper III, a class of non-linear two-stage structured population models is studied with different growth rates for the unstructured food resource under different harvesting rates in both deterministic and stochastic settings. In the stochastic setting, we develop methods to evaluate emergent properties equivalent to the properties investigated in the deterministic case. In addition, new emergent properties, e.g. probability of extinction, are also investigated.In Paper IV, we explore the stem model which is developed by combining the pipe model and the branch thinning model. The stem model provides estimates of the heartwood, sapwood and stem cross-sectional area at any height. We corroborate the accuracy of our model with empirical data and the cross validation of our results shows a very high goodness of fit for the stem model.
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| 26. |
- Aysan, Hüseyin, 1982-
(författare)
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Fault-Tolerance Strategies and Probabilistic Guarantees for Real-Time Systems
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ubiquitous deployment of embedded systems is having a substantial impact on our society, since they interact with our lives in many critical real-time applications. Typically, embedded systems used in safety or mission critical applications (e.g., aerospace, avionics, automotive or nuclear domains) work in harsh environments where they are exposed to frequent transient faults such as power supply jitter, network noise and radiation. They are also susceptible to errors originating from design and production faults. Hence, they have the design objective to maintain the properties of timeliness and functional correctness even under error occurrences. Fault-tolerance plays a crucial role towards achieving dependability, and the fundamental requirement for the design of effective and efficient fault-tolerance mechanisms is a realistic and applicable model of potential faults and their manifestations. An important factor to be considered in this context is the random nature of faults and errors, which, if addressed in the timing analysis by assuming a rigid worst-case occurrence scenario, may lead to inaccurate results. It is also important that the power, weight, space and cost constraints of embedded systems are addressed by efficiently using the available resources for fault-tolerance. This thesis presents a framework for designing predictably dependable embedded real-time systems by jointly addressing the timeliness and the reliability properties. It proposes a spectrum of fault-tolerance strategies particularly targeting embedded real-time systems. Efficient resource usage is attained by considering the diverse criticality levels of the systems' building blocks. The fault-tolerance strategies are complemented with the proposed probabilistic schedulability analysis techniques, which are based on a comprehensive stochastic fault and error model.
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| 27. |
- Azimoh, Chukwuma Leonard, 1970-
(författare)
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Sustainability and development impacts of off-grid electrification in developing countries : An assessment of South Africa's rural electrification program
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Previous studies have shown that provision of sustainable electricity supply to rural households is essential to bring development to off-grid populations. For this reason, most developing countries put large efforts into rural electrification programs to stimulate development and reduce poverty. However, to be sustainable these programs need to recover costs, which poses a challenge to remote low income populations. This often forces governments and other institutions involved in rural electrification to subsidize the electricity production. It also affects the choice of technology and places a barrier on the level of energy provided in line with the ability to pay for services. As a result of this, most programs have failed to achieve the desired objectives, as the technologies used often do not support income generating activities that could increase the payment capabilities of the beneficiaries and contribute to development.This thesis is focused on the rural electrification program of South Africa, the country in sub-Saharan Africa that has the highest access to electricity. It investigates the success elements that influence the sustainability of rural electrification programs and their contributions to socio-economic development. This was achieved by evaluating the South African program that provides solar home systems to off-grid communities, and a hybrid solar-wind mini-grid project in South Africa. The study also draw lessons from other rural electrification programs in neighbouring countries, i.e. an evaluation of a hybrid solar-diesel mini-grid system in Namibia, and a review of two systems, a hybrid solar-biomass mini-grid project in Botswana and a hydro mini-grid program in Lesotho. The study revealed that hydro based hybrid mini-grid systems provide the most cost effective way of bringing energy services to rural settlements. Regardless of technology, successful programs depend on adequate support from the government, implementation of a progressive tariff system that allows the high consuming high income earners and businesses, to cross subsidize the low consuming , low income users. It shows that it is more likely for rural electrification programs to survive if the design considers the existing businesses, population growth and the corresponding load increase. The thesis further shows that provision of sufficient energy to induce income generating activities is essential to decrease the need for subsidies and to ensure the sustainability of programs. In addition, availability of spare parts and a capable management team is essential for the successful operations and maintenance of these systems.
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| 28. |
- Backlund Björke, Andreas, 1978-
(författare)
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Waves of fashion : The consuming production of management control
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The responsiveness of organizational leaders regarding suggestions related to various managerial techniques has led to the coinage of the ‘management fashion’ idiom. It has been convincingly argued that phenomena like management control systems are prone to trends, and that such trends permeate into the daily life of managers through the use of persuasive rhetoric. This thesis is a theory-generating study of change in management control systems. More precisely, its purpose is to seek an understanding of how fashions within the field of management control emerge through processes of interaction and co-production. By asking the question “how do the forces involved in the shaping of a market for management control systems interact and combine in order to create management fashions?” the thesis seeks to generate a comprehensive conjecture on the management fashion setting process. The thesis is based on an empirical case study completed with extensive literature readings. In order to generate theory, a methodology based on abductive reasoning has been produced. Theoretically, the thesis borrows from micro sociological theory on imitation and co-production but extends also into such fields as psychology, aesthetics, rhetoric and economics; aside from the obvious management control and management accounting themes. The thesis concludes by producing a comprehensive model of the management fashion setting process. The contribution of the thesis can be understood as either providing an alternative to or completing the dominant interpretation of the phenomena. The main difference between the arrived at suggestion and the prevailing interpretation is the role of the actors which is changed from norm following consumers of fashion to creative producers of fashion. This change represents a change in scientific traditions and necessitates the adoption of additional frames of reference when studying management fashion phenomena.
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| 29. |
- Bader, Britt-Marie, 1960-
(författare)
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Att lyssna med hela kroppen : en studie om lärares ledarskap i utvecklingssamtal
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Keywords: Teachers´ leadership, parents-teachers ‘conference, primary school, didactic, hermeneutic, lifeworld phenomenologyThis thesis aims to explain what importance teachers´ leadership is given and how teachers' leadership appears in the parents-teacher conferences. The theoretical frame is lifeworld phenomenology, which means that the world is a social, intersubjective, and historical world where people experience, act, and intertwine in a private and a shared world. The study is inspired by a lifeworld approach and the data was analyzed to consider people's context, their experiences and the challenges involved in leading parent-teacher conferences. The empirical work is based on observations of parent-teacher conferences and interviews with teachers and students. The analyses are made with the support of the life-world phenomenological concepts of hållning, seeing-as and pedagogical tact. The concept hållning has a duality and loses its meaning in translation. Hållning means a bodily approach and is an intertwining between the teacher's attitude and her body posture. All three concepts include verbal and bodily communicative expressions and sensitive and intuitive actions, their meanings will be highlighted and explained. The results show that teachers' leadership in parent-teacher conferences includes both preparatory and subsequent work and forms part of the teaching. Leadership both shapes the parent-teacher conference and is shaped in the same and given importance when teachers show consideration for the student, the relationship between teacher and student and the situation, balance challenges with time and sensitive topics, choose to take notes in the parent-teacher conferences in favor of presence in the conversation itself and document afterwards. Teachers' leadership in parent-teacher conferences shape the conversation through teachers' willingness to involve the students, flexibility, and ability to structure. Teachers' leadership in parent-teacher conferences are shaped by teachers' responsiveness, compliance, presence, attention, ability to improvise and playfulness.The study's life-world phenomenological approach has made it possible to see that the parent-teacher conference requires a didactic knowledge related to the student as a person, to the content and to the structure that surrounds the conversation. This has been made visible in teachers' intuitive actions and bodily expressions as well as unreflected and reflected experiences. The study's starting points have made it possible to broaden the didactic understanding of the teachers' leadership in parent-teacher conferences by highlighting the clear intertwining of these conferences with other teaching
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| 30. |
- Bakhshi, Zeinab, 1986-
(författare)
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Lightweight Persistent Storage for Industrial Applications
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Clouds are large computer centers that offer remote access to computing and storage resources, making them popular for business and web applications. They are now being considered for use in safety-critical applications such as factories, but lack sufficient time predictability, which makes it challenging to use them in these time-sensitive applications. To overcome this limitation, an intermediate layer, the fog layer, is introduced to provide computational resources closer to the network edge. However, this new computing paradigm faces its own challenges in resource management, scalability, and reliability due to resource constrained nodes. Lightweight virtualization technologies like containerization can solve the performance-reliability dichotomy in fog computing and provide built-in fault tolerance mechanisms. By studying a robotic use-case, we realized the critical importance of persistent data storage for stateful applications, such as many control applications. However, container-based solutions lack fault-tolerant persistent storage. In this thesis, we identify new challenges associated with leveraging container-based architectures, particularly the importance of persistent storage for stateful applications. We investigate the design possibilities for persistent fault-tolerant storage and propose a solution adapted to container-based fog architectures and tailored for stateful applications. The solution provides scalability, auto recovery, and re-integration after failures at application and node levels. Key elements are a replicated data structure and a storage container, using a consensus protocol for distributed data consistency and fault tolerance in case of node failures. The fault tolerance and consistency of the solution are modeled and verified, and its timing requirements evaluated. We use simulation to evaluate the timing performance of our solution in larger set-ups. The results of our study show that although adding a consistency protocol introduces a timing overhead, the solution still meets timing requirements for the studied use-case even in presence of a set of relevant faults. By leveraging a four-dimensional approach, we also conduct a comparative analysis of our solution with other approaches from various perspectives, indicating that our solution can be applied in a broader context than initially intended.
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| 31. |
- Bartusch, Cajsa, 1965-
(författare)
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Boosting behavioral change in residential electricity consumption : demand response programs and feedback
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As part of realizing national and European climate ambitions, it is imperative to bring about increased energy efficiency and consumption flexibility in the residential sector of the Swedish power market. In addition to governmental policy instruments to this end, market-based measures play an important role in making behavioral change in domestic electricity use happen. In light of the prevailing lack of incentives for residential consumers to save electricity and cut peak demand at times of physical and financial market constraints, the research studies that form the basis of this thesis have the aim of adding to the body of knowledge on policy instruments for the purpose of boosting behavioral change in residential electricity consumption. The research has accordingly contributed to the general statistics on residential electricity consumption, which constitute the starting point for policy instrument development, and augmented knowledge on the merits of residential demand response programs involving hourly settlements in power trading and demand-based, time-of-use tariffs in power distribution as well as graphic feedback on individual households’ electricity use by means of a statistics service provided over the Internet. The overall results have shown that household behavior, together with physical factors such as heating systems, help explain the sizeable differences in electricity consumption among homeowners. Statistical analysis of variance has in this context proven to be an effective method for identifying key indicators of policy development. Power suppliers and electricity consumers as well as society as a whole have been found to gain substantially from hourly settlements in retail. To suppliers, the greatest benefits are associated with risk management, while the major advantage to customers is that they are provided with an opportunity to reduce their electricity costs. It has also been empirically demonstrated that electricity users are willing to adjust their consumption to a demand-based, time-varying distribution tariff. Households generally have a favorable attitude towards this type of distribution tariff, seeing as they indirectly have a positive impact on the environment. Providing households with feedback over the Internet on their individual electricity use and demand has been shown to contribute to an increased awareness and lead to energy efficiency in homes. Easy accessibility and simplicity have proven to be key success factors in this context. Combining conventional bar charts, color symbolism and historic feedback is expedient in this respect.
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| 32. |
- Baumgart, Stephan
(författare)
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Safety Analysis of Systems-of-Systems
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Safety-critical systems may fail dangerously with severe consequences to the health of the involved humans, costly equipment, the environment, or other valuable assets of a stakeholder. For these classes of systems, the developers are obliged to analyze each potentially hazardous situation thoroughly. In addition, any identified hazardous situation needs to be considered for risk reduction measures, including adjustments of the system's design, additional safeguards if the hazards cannot entirely be removed by design, or warning information to users. An essential activity in the development process is the safety analysis, where hazards related to the system under development are identified, and the risks are evaluated and classified. This classification stipulates the rigor of complying with safety standard requirements and directing the development and verification activities. Several techniques for safety analysis have been identified in the literature and are applied in industrial development processes.The technical evolution enables moving from developing single systems with specific features towards attaching several independent systems to a system-of-systems.On top of the trend towards connectedness, there is also a trend towards more and more automation. In the vehicle domain, autonomous vehicles can collaborate to achieve specific goals, like transporting goods in warehouses, transporting containers in automated ports, or transporting material in off-road environments.Autonomy brings in new challenges when ensuring product safety and functional safety for single systems due to the lack of a human operator as a fallback solution.Further, when autonomous vehicles collaborate in a fleet, the safety analysis becomes more complex since their interaction and interoperability bring forth new hazards not identifiable with a safety analysis of a single system. Our research aims to bridge this gap and provide solutions for specifying a system-of-systems and finding and developing suitable safety analysis methods.To understand the challenges and current practices, we have studied industrial projects where systems-of-systems are developed. We have applied safety analysis methods to our industrial cases and found limitations of finding hazards related to a system-of-systems. As part of our research, we have developed extensions to the safety analysis methods to support the analysis of a system-of-systems. We have developed the Safe System-of-Systems (SafeSoS) method which is a structured and hierarchical process to discover and document a system-of-systems characteristics on three primary abstraction levels. Additionally, we utilize model-based formalism to describe the System-of-Systems’ characteristics on each level. Our research results support engineers in the industry when designing a safety-critical system-of-systems.
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| 33. |
- Becker, Matthias, 1986-
(författare)
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Consolidating Automotive Real-Time Applications on Many-Core Platforms
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Automotive systems have transitioned from basic transportation utilities to sophisticated systems. The rapid increase in functionality comes along with a steep increase in software complexity. This manifests itself in a surge of the number of functionalities as well as the complexity of existing functions. To cope with this transition, current trends shift away from today’s distributed architectures towards integrated architectures, where previously distributed functionality is consolidated on fewer, more powerful, computers. This can ease the integration process, reduce the hardware complexity, and ultimately save costs.One promising hardware platform for these powerful embedded computers is the many-core processor. A many-core processor hosts a vast number of compute cores, that are partitioned on tiles which are connected by a Network-on-Chip. These natural partitions can provide exclusive execution spaces for different applications, since most resources are not shared among them. Hence, natural building blocks towards temporally and spatially separated execution spaces exist as a result of the hardware architecture.Additionally to the traditional task local deadlines, automotive applications are often subject to timing constraints on the data propagation through a chain of semantically related tasks. Such requirements pose challenges to the system designer as they are only able to verify them after the system synthesis (i.e. very late in the design process).In this thesis, we present methods that transform complex timing constraints on the data propagation delay to precedence constraints between individual jobs. An execution framework for the cluster of the many-core is proposed that allows access to cluster external memory while it avoids contention on shared resources by design. A partitioning and configuration of the Network-on-Chip provides isolation between the different applications and reduces the access time from the clusters to external memory. Moreover, methods that facilitate the verification of data propagation delays in each development step are provided.
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| 34. |
- Begum, Shahina, 1977-
(författare)
-
A Personalised Case-Based Stress Diagnosis System Using Physiological Sensor Signals
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stress is an increasing problem in our present world. It is recognised that increased exposure to stress may cause serious health problems if undiagnosed and untreated. In stress medicine, clinicians’ measure blood pressure, Electrocardiogram (ECG), finger temperature and respiration rate etc. during a number of exercises to diagnose stress-related disorders. However, in practice, it is difficult and tedious for a clinician to understand, interpret and analyze complex, lengthy sequential sensor signals. There are few experts who are able to diagnose and predict stress-related problems. Therefore, a system that can help clinicians in diagnosing stress is important. This research work has investigated Artificial Intelligence techniques for developing an intelligent, integrated sensor system to establish diagnosis and treatment plans in the psychophysiological domain. This research uses physiological parameters i.e., finger temperature (FT) and heart rate variability (HRV) for quantifying stress levels. Large individual variations in physiological parameters are one reason why case-based reasoning is applied as a core technique to facilitate experience reuse by retrieving previous similar cases. Feature extraction methods to represent important features of original signals for case indexing are investigated. Furthermore, fuzzy techniques are also employed and incorporated into the case-based reasoning system to handle vagueness and uncertainty inherently existing in clinicians’ reasoning. The evaluation of the approach is based on close collaboration with experts and measurements of FT and HRV from ECG data. The approach has been evaluated with clinicians and trial measurements on subjects (24+46 persons). An expert has ranked and estimated the similarity for all the subjects during classification. The result shows that the system reaches a level of performance close to an expert in both the cases. The proposed system could be used as an expert for a less experienced clinician or as a second opinion for an experienced clinician to supplement their decision making tasks in stress diagnosis.
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| 35. |
- Behnam, Moris, 1973-
(författare)
-
Synchronization Protocols for a Compositional Real-Time Scheduling Framework
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis we propose techniques to simplify the integration of subsystems while minimizing the overall amount of CPU resources needed to guarantee the schedulability of real-time tasks. In addition, we provide solutions to the problem of allowing for the use of logical resources requiring mutual exclusion.The contribution of the thesis is presented in three parts. In the first part, we propose a synchronization protocol, called SIRAP, to facilitate sharing of logical resources in a hierarchical scheduling framework. In addition, we extend an existing synchronization protocol, called HSRP, such that each subsystem can be developed independently. The performance of the proposed protocols is evaluated by extensive simulations. In the second part, we present an efficient schedulability analysis that exploits the lower scheduling overhead introduced by each of the proposed protocols. Finally, in the third part, we propose new methods and algorithms that find the optimal system parameters (e.g., optimal resource ceiling), that minimize the amount of CPU resources required to ensure schedulability, when using the proposed synchronization protocols in a hierarchical scheduling framework.The motivation of this work comes from an emerging industrial trend in embedded software systems development to integrate multiple applications (subsystems) on a small number of processors. The purpose of this integration is to reduce the hardware related costs as well as the communication complexity between processors. In this setting a large number of industrial applications face the problem of preserving their real-time properties after their integration onto a single processor. In addition, temporal isolation between the applications during runtime may be required to prevent failure propagation between different applications.Specifically, we propose a hierarchical scheduling framework that allows for a simplified integration of subsystems. The framework preserves the essential temporal characteristics of the subsystems, both when running in isolation as well as when they are integrated with other subsystems. In this thesis, we assume a model where a system consists of a number of subsystems. The subsystems can interact with each other using shared logical resources. The framework ensures that the individual subsystem respects its allocated share of the processor. The difficulty lies in allowing two or more subsystems to share logical resources, which introduces an additional complexity in the schedulability analysis and also increases the system load.
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| 36. |
- Bengtsson, Marcus, 1977-
(författare)
-
On Condition Based Maintenance and its Implementation in Industrial Settings
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to stay competitive, it is necessary for companies to continuously increase the effectiveness and efficiency of their production processes. High availability has, thus, increased in importance. Therefore, maintenance has gained in importance as a support function for ensuring, e.g., quality products and on-time deliveries. Maintenance, though, is a costly support function. It has been reported that as much as 70% of the total production cost can be spent on maintenance. Further, as much as one-third of the cost of maintenance is incurred unnecessarily due to bad planning, overtime cost, limited or misused preventive maintenance, and so on. In so, condition based maintenance is introduced as one solution for a more effective maintenance.In condition based maintenance, critical item characteristics are monitored in order to gain early indications of an incipient failure. Research, though, has shown that condition based maintenance has not been implemented on a wide basis. Therefore, the purpose of this research is to investigate how a condition based maintenance approach can be implemented in an industrial setting, and to develop a method that can assist companies in their implementation efforts. Further, the research has been divided in three research questions. They focus on: constituents of a condition based maintenance approach, decision-making prior implementation of condition based maintenance, and finally, the implementation of condition based maintenance in a company.By using a systems approach and a case study process, how condition based maintenance can be implemented as a routine has been investigated. The result is an implementation method in which four suggested phases are presented. The method starts with a feasibility test. It then continues with an analysis phase, an implementation phase, and an assessment phase. The conclusions can be summarized as follows: implementing condition based maintenance consists of many general enabling factors, including management support, education and training, good communication, and motivation etc.
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| 37. |
- Berg, Benita, 1976-
(författare)
-
REFORMERS PÅVERKAN PÅ LÄRARES UNDERVISNING I GRUNDSKOLAN OCH FÖRSKOLAN : En läroplansteoretisk studie om undervisningsuppdraget och lärarrollen i förändring
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis is to use a curriculum theoretical perspective to contribute knowledge about the impact of recent reforms on teachers’/preschool teachers’ teaching, with a special focus on mathematics. The thesis takes its starting point in a licentiate thesis that was completed in 2014. The further doctoral studies are based on two articles. These articles answer specific research questions. Substudy 1 was a systematic literature review that focused on the role of the preschool teacher in teaching mathematics in preschool. Substudy 2 explored how preschool teachers interpret their teaching mission based on the curriculum’s directives and how they describe the meaning of the concept of preschool teaching. The data from Substudy 1 consisted of 68 research articles, and Substudy 2 was based on 50 preschool teachers’ reflection texts. The theoretical underpinnings of the thesis are two theoretical perspectives: curriculum theory and Bernstein’s theory of pedagogic practice. The results from the two substudies show the importance of preschool teachers having both subject knowledge and didactic competence to carry out teaching in spontaneous situations and planned activities. The results from Substudy 1 show two different roles that preschool teachers adopt when teaching mathematics in preschool education guided by social pedagogical or pre-primary curriculum traditions; these are the role of instructor and the role of an interactor. In the research studies, preschool teachers provide instruction with planned subject content or interact with the children’s play and other everyday situations to promote children’s mathematics learning. The results from Substudy 2 show an education that is guided by invisible pedagogy within the social pedagogical curriculum tradition. The preschool teachers describe teaching taking place spontaneously in play and other everyday situations based on children’s own interests and needs. The preschool teachers also have a purpose with the teaching, and they plan activities together with the children. These reveal teaching governed by visible pedagogy, which is characteristic of the pre-primary curriculum tradition. Furthermore, there are indications that a new curriculum tradition is emerging bearing some similarities to previous traditions, an approach that is both play-based and goal-oriented. Children’s participation and influence are central in the teaching, which means that the teaching conforms to the children’s interests, and that goals from the curriculum are woven into the everyday work. The preschool teacher consciously shapes the environment in the preschool and uses materials to promote children’s learning, and the teaching has more distinct subject content. Together with the licentiate study, the two substudies show that teachers and preschool teachers have difficulty transforming a new curriculum text into practically applicable form. The curricula leave room for interpretation, and the uncertainty that arises in the transformation arena shows that they need support to realize the curriculum’s new guidelines.
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| 38. |
- Berglund, Karin, 1967-
(författare)
-
Jakten på Entreprenörer : Om öppningar och låsningar i entreprenörskapsdiskursen
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Entrepreneurs are expected to play a crucial role in times of unemployment and economical regression. A “hunt for entrepreneurs” can thus be said to be occurring as they appear to be people who can save nations, societies, and companies in troublesome situations. The project Diversity in Entrepreneurship (DiE) aimed to introduce a broad view of entrepreneurship in a regional context. Three development areas are emphasized that are strategically important to transforming a traditional industrial community into an entrepreneurial region: paying attention to the spirit of enterprise among underrepresented groups; stimulating entrepreneurship among young people; and considering the importance of culture in stimulating a diverse and entrepreneurial society.An equality discourse is introduced through DiE that – emphasising social and mundane occurrences - stands in contrast to the historically rooted enterprise discourse that proffers companies as productive apparatus, where a few competent people – often men – have been, and still are, in charge. In the equality discourse, all people in the region make a difference, not merely a few. The encounter of the two discourses has resulted in confusion, and thus conflicts and collisions; but also in new possibilities.A new perspective of entrepreneurship and regional development is developed where conflicts are put forward as constructive. That the two discourses met on the same regional scene is therefore seen as positive as many people have been made aware of the social, political, and economic contradictions which restrain some groups in society from creating a (working) life. Hence, the contradictions have enabled the inhabitants to see themselves, and others, as entrepreneurs in regional development processes. Openings have thus emerged to view entrepreneurship from a broader perspective that includes people, to create practices through which a more diverse working life is becoming discernible.
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| 39. |
- Bergwall, Andreas, 1972-
(författare)
-
Proof-related reasoning in upper secondary mathematics textbooks : Characteristics, comparisons, and conceptualizations
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Proofs and proving are difficult to learn and difficult to teach. A common problem is that many students use specific examples as evidence for general statements. Difficulties with proofs are also part of the transition problems that exist between secondary and tertiary schooling in mathematics. As mathematics teaching often follows a textbook, the design of textbooks has been pointed out as one possible cause of the problems, and international textbook research suggests that proofs often have only a marginal place in textbooks.This thesis focuses on proofs and proving in upper secondary mathematics textbooks. It also addresses theoretical and methodological questions about what marks an opportunity to develop proving competence, and which properties of such opportunities are relevant to investigate and characterize. The thesis is based on data from four Swedish and Finnish textbook series for upper secondary school, and focuses on sections on logarithms, primitive functions, definite integrals, and combinatorics. It examines how addressed mathematical principles are justified, and whether the textbooks’ exercises offer opportunities to develop proof-related skills such as formulating and investigating hypotheses, developing and evaluating arguments, identifying and correcting errors, and finding counterexamples.The results show that just over half of the mathematical principles addressed in the analyzed textbook material are justified, and that only half of the justifications are general proofs. Few exercises are proof-related (10%), and those that include reasoning about general cases even fewer. General proofs are more common in the Finnish books, but proof-related tasks are more common and of a more varied nature in the Swedish ones. The most common form of proofs are direct derivations of calculation formulas, while reasoning about existence and uniqueness is unusual, as are contrapositive proofs and proofs by contradiction.Based on the results, explicit suggestions are offered as to what teaching can pay more attention to. For the analysis and design of proof-related activities, a framework consisting of four main categories is proposed: develop a statement, investigate a statement, develop an argument, and investigate an argument. Several properties that such activities may have, regardless of which category they belong to, are discussed. Finally, three areas for future research are suggested: how worked examples can support students’ learning of proof, how textbooks can be designed to stimulate formulation as well as the formal proving of hypotheses, and mapping of differences regarding proof between upper secondary and university textbooks.
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| 40. |
- Blackbright, Helena, 1972-
(författare)
-
Exploring Purposeful use of Innovation Self-assessments
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Innovation management is a multidimensional practice characterized by the requirement of a constant renewal to maintain an organization’s relative innovativeness. A practice highly characterized by a requirement to handle uncertainty, risk, and long lead times, which requires an active management of both the prerequisites of today and a yet-undefined future. Therefore, it is of little surprise that the so-called “innovation audits,” with their purpose of direct or indirect improvement are often considered a vital part of innovation management practices. This thesis focuses on the internal self-assessment use of such audits by organizations to self-assess their current state of innovativeness against indicators of good practice or their own prior state. The purpose of such innovation audits is to reveal gaps between the current and desired state, which the organization can use to develop improvement activities.Substantial empirical and theoretical research on innovation audits exists, which focuses primarily on the development of the audit itself, but seldom on enacting audits that lead to desired improvements. Much innovation audit research discusses the areas to assess and the development of different types of indicators, statements, and framework, which represents these assessment areas. The problem is that no matter how well the indicators identify possible improvement areas or gaps between current and desired states, it still says very little about integrating retrieved information into activities that actually lead to the desired improvements.This thesis takes a process perspective on the undertaking of an innovation self-assessment audit (ISA). Rather than examining what to assess and how to use the result, it focuses on the undertaking of an ISA as an improvement process in itself. The overall objective is to contribute to the understanding of why a purposeful use of ISA emerges (or does not emerge). To this end, this thesis collects empirical data about ISA use and its context from qualitative case studies, involving 14 self-assessment groups from 9 different organizations. The findings from these studies is presented in the six appended papers that address different perspectives on ISA use and contextual prerequisites.To better understand why a purposeful use of ISA emerges (or does not), it was necessary to bring the appended papers together and undertake a more focused discussion on ISA use as a process in its entirety. Therefore, this thesis recontextualizes the six appended papers against a new theoretical framework based on theories on processes, complex adaptive systems (CAS), and competence-in-use.The theoretical discussion in this thesis offers several contributions. First, by approaching the undertaking of ISA as an improvement process, it focuses on the continuity of the process, which in turn allows a distinction between the execution of the process and the enabling of this execution. Second, the enactment of purposeful use is related to knowledge about the focus area of the assessment (e.g. innovation culture or capabilities) and the current state being assessed. Together, these create the basis for the theorization of a four-dimensional ISA competence-in-use that impacts how ISA can be purposefully enacted. Overall, the main reason why purposeful use emerges (or does not) does not seem to be so much about having a high ISA competence-in-use, as having high correspondence between expectations and competence-in-use.Together, this contributes to an increased understanding of why purposeful use emerges (or does not), making this its primary contribution within the field of innovation management. The focus on self-assessment use as an improvement process embedded in the organizational context it intends to improve, does give a more general relevance to the discussion on improvement processes, and the use of self-assessment audits outside the field of innovation management.The contribution of this thesis is closely related to the use of ISA and can be used to support the process of planning and undertaking an ISA. This thesis also contributes to knowledge on ISA competence-in-use, which can guide practical choices in undertaking an ISA for more purposeful use.
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| 41. |
- Blackman, Corey
(författare)
-
Evaluation of Modular Thermally Driven Heat Pump Systems
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The building sector accounts for approximately 40% of primary energy use within the European Union, therefore reductions in the energy use intensity of this sector are critical in decreasing total energy usage. Given that the majority of energy used within the built environment is for space conditioning and domestic hot water preparation, prudence would suggest that decreasing primary energy used for these end purposes would have the biggest overall environmental impact. A significant portion of the energy demands in buildings throughout the year could potentially be met using solar energy technology for both heating and cooling. Additionally, improving the efficiency of current heating and cooling appliances can reduce environmental impacts during the transition from non-renewable to renewable sources of energy. However, in spite of favourable energy saving prospects, major energy efficiency improvements as well as solar heating and cooling technology are still somewhat underutilised. This is typically due to higher initial costs, and lack of knowledge of system implementation and expected performance. The central premise of this thesis is that modular thermally (i.e., sorption) driven heat pumps can be integrated into heating and cooling systems to provide energy cost savings. These sorption modules, by virtue of their design, could be integrated directly into a solar thermal collector. With the resulting sorption integrated collectors, cost-effective pre-engineered solar heating and cooling system kits can be developed. Sorption modules could also be employed to improve the efficiency of natural gas driven boilers. These modules would effectively transform standard condensing boilers into high efficiency gas-driven heat pumps that, similar to electric heat pumps, make use of air or ground-source heat. Based on the studies carried, sorption modules are promising for integration into heating and cooling systems for the built environment generating appreciable energy and cost-savings. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a sorption integrated solar heating and cooling installation versus a state-of-the-art heating and cooling system. Additionally, a sorption integrated gas-fired condensing boiler yielded annual energy savings of up to 14.4% and corresponding annual energy cost savings of up to €196 compared to a standard condensing boiler. A further evaluation method for sorption modules, saw the use of an artificial neural network (ANN) to characterise and predict the performance of the sorption module under various operating conditions. This generic, application agnostic model, could characterise sorption module performance within a ± 8% margin of error. This study thus culminates in the proposal of an overall systematic evaluation method for sorption modules that could be employed for various applications based on the analytical, experimental and simulation methods developed.
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| 42. |
- Bohlin, Markus, 1976-
(författare)
-
A Study of Combinatorial Optimization Problems in Industrial Computer Systems
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A combinatorial optimization problem is an optimization problem where the number of possible solutions are finite and grow combinatorially with the problem size. Combinatorial problems exist everywhere in industrial systems. This thesis focuses on solving three such problems which arise within two different areas where industrial computer systems are often used. Within embedded systems and real-time systems, we investigate the problems of allocating stack memory for an system where a shared stacks may be used, and of estimating the highest response time of a task in a system of industrial complexity. We propose a number of different algorithms to compute safe upper bounds on run-time stack usage whenever the system supports stack sharing. The algorithms have in common that they can exploit commonly-available information regarding timing behaviour of the tasks in the system. Given upper bounds on the individual stack usage of the tasks, it is possible to estimate the worst-case stack behaviour by analysing the possible and impossible preemption patterns. Using relations on offset and precedences, we form a preemption graph, which is further analysed to find safe upper-bounds on the maximal preemptions chain in the system. For the special case where all tasks exist in a single static schedule and share a single stack, we propose a polynomial algorithm to solve the problem. For generalizations of this problem, we propose an exact branch-and-bound algorithm for smaller problems and a polynomial heuristic algorithm for cases where the branch-and-bound algorithm fails to find a solution in reasonable time. All algorithms are evaluated in comprehensive experimental studies. The polynomial algorithm is implemented and shipped in the developer tool set for a commercial real-time operating system, Rubus OS. The second problem we study in the thesis is how to estimate the highest response time of a specified task in a complex industrial real-time system. The response-time analysis is done using a best-effort approach, where a detailed model of the system is simulated on input constructed using a local search procedure. In an evaluation on three different systems we can see that the new algorithm were able to produce higher response times much faster than what has previously been possible. Since the analysis is based on simulation and measurement, the results are not safe in the sense that they are always higher or equal to the true response time of the system. The value of the method lies instead in that it makes it possible to analyse complex industrial systems which cannot be analysed accurately using existing safe approaches. The third problem is in the area of maintenance planning, and focus on how to dynamically plan maintenance for industrial systems. Within this area we have focused on industrial gas turbines and rail vehicles. We have developed algorithms and a planning tool which can be used to plan maintenance for gas turbines and other stationary machinery. In such problems, it is often the case that performing several maintenance actions at the same time is beneficial, since many of these jobs can be done in parallel, which reduces the total downtime of the unit. The core of the problem is therefore how to (or how not to) group maintenance activities so that a composite cost due to spare parts, labor and loss of production due to downtime is minimized. We allow each machine to have individual schedules for each component in the system. For rail vehicles, we have evaluated the effect of replanning maintenance in the case where the component maintenance deadline is set to reflect a maximum risk of breakdown in a Gaussian failure distribution. In such a model, we show by simulation that replanning of maintenance can reduce the number of maintenance stops when the variance and expected value of the distribution are increased. For the gas turbine maintenance planning problem, we have evaluated the planning software on a real-world scenario from the oil and gas industry and compared it to the solutions obtained from a commercial integer programming solver. It is estimated that the availability increase from using our planning software is between 0.5 to 1.0 %, which is substantial considering that availability is currently already at 97-98 %.
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| 43. |
- Bojesson, Catarina
(författare)
-
Enabling Dynamic Capability : Managing and Organizing for Change
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis is based on a longitudinal single-case study conducted over five years within a product development context at a manufacturing company. In dynamic environments that demand flexibility and adaptability, it is essential to understand how organizations can improve dynamic capabilities to remain viable and competitive during periods of turbulence and change. This challenge is especially central to product development organizations offering customer-specific products as it tends to increase organizational complexity. An excessive focus on internal coordination and control to manage this complexity has led to inertia due to establishment of strict, rigid processes and hierarchical bureaucracies within organizational management and design.This study aims to contribute with new knowledge on how organizations operating in dynamic contexts can develop adaptability to changing needs. Specifically, it seeks to understand how to design and manage organizations to increase their preparedness for and adaptability to change. Investigating the factors and mechanisms that influence an organization's dynamic capability can provide insights into the sources of inertia and support the transition toward a more dynamic structure. The longitudinal study is based on data collected through an initial interview study followed by a questionnaire study, and finally through a concluding interview study. The research has been phenomenon-driven; as the organization’s circumstances have evolved, the focus of the study has shifted accordingly. Emerging from the aggregated results of the longitudinal study, the overall scope of the research is the change process, transitioning from a rigid to a more dynamic organization. Research findings are presented in five appended papers.Analysis from literature studies and the empirical study show that the primary focus on improving performance often centers on internal efficiency. However, within the case company, tension arose between the desire of strict control according to predefined processes and plans and the actual need for flexibility. Dynamic contexts require working processes that facilitate reactive problem-solving, creativity, and flexibility, as well as managers capable of going back and forth between management styles to benefit performance. Successful organizational reconfiguration depends on developing the conditions that enable the firm's dynamic capability in relation to its context. This involves identifying both the microfoundations that generate dynamic capability and the internal and external constraints to change.Considering the external environment is crucial for developing an understanding of how to best organize and manage resources and capabilities, which places demands on managerial capabilities. Managers must possess the skills to monitor the external environment and formulate strategies to respond to changing conditions, as their interpretation of the external environment will influence their decisions, which will subsequently enable or hinder possible actions. The design of organizations will impact the ability to rearrange resources and capabilities. Processes and working procedures must allow for reconfigurations to respond swiftly to changing constraints or opportunities. The use of multiple theoretical perspectives has been imperative in the analysis of the data, and the theoretical contribution extends to exploration of various factors and mechanisms that influence an organization's dynamic capability.
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| 44. |
- Bozic, Nina
(författare)
-
Choreographing innovative practice in everyday work
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis argues for a humanistic and democratic approach to innovation management that puts employees and their engagement in the center of organizational efforts for innovation. It proposes that a culture for innovation can be built by enabling all employees to develop their innovative practice as part of their everyday work and not as an extra activity on top of their existing responsibilities. The aim of this approach to innovation is to build more human-centered organizations that help employees improve their own motivation, creativity, well-being, and self-fulfillment at work. This presupposes that they need to be able to connect with their body, feelings, fantasy, intuition, and will, and to be able to innovate more from within, balancing external expectations from management and users with their own personal needs. Since there is a lack of discussing embodied aspects of knowledge and learning in connection to innovative competence in the current innovation management literature, knowledge and methods from contemporary dance and choreography are explored to support a more holistic approach to innovative competence development. Based on integrating research from both innovation management and contemporary dance fields, a model of innovative practice in everyday work is developed. The model suggests what kind of skills and activities can enable employees develop their personal innovative practice that is adjusted to their work context and their specific needs. It is proposed that as employees practice innovating in everyday work, they will slowly move from innovating incrementally towards developing the competence for more radical innovation. Different practical tools and exercises for enabling innovative competence development that were inspired by choreographic practices, and adjusted and tested in organizational context are described. Ideas around how contemporary dance and choreography can be used to design and implement long-term art-based interventions in organizations that can create value on strategic level are proposed. The research approach used in the thesis is participatory action research done by several iterative cycles between practice and theory. Two empirical and two theoretical studies that were part of the research process are presented. The empirical studies were implemented in the Eskilstuna municipality and at the Art of Management and Organization conference. The theoretical studies were performed in the fields of innovative competence and contemporary dance and choreography.
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| 45. |
- Brahneborg, Daniel, 1970-
(författare)
-
Improving the Efficiency and Reliability of Text Messaging Gateways
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When software communicates, it typically uses some middleware. In this thesis we focus on the group of middleware called “messaging gateways”, which normally uses the store-and-forward architecture. Our overall goal is to find ways to improve the throughput and reliability of such gateways in general, in particular the ones used for forwarding mobile text messages. In short, our work resulted in a new anomaly detection algorithm, a reduction of the number of database operations in a commercial messaging gateway, and two new highly performant data replication protocols.In addressing the throughput, we first wanted a better understanding of how the round-trip times for outgoing requests varied, in order to correctly detect abnormal delays. This resulted in a generalized extension of exponential smoothing, which we used in a novel algorithm to detect anomalies.We then performed an architecture analysis of an industrial messaging gateway based on its quality requirements. From this exploratory case study, we deduced a somewhat unexpected plan to migrate the balance management module to a set of microservices, and identified situations where database operations could be batched in order to also provide higher throughput.A common and easy way to improve the reliability of a system is to replicate the stored data to one or more additional servers. However, we found that this approach often leads to lower throughput due to extra network traffic required. We addressed this by first writing a problem formulation on how the quality attributes of a messaging gateway would be affected by a multi-node configuration, resulting in a review of state of the art and state of practice for multi-node systems. Building on this review, we developed a new data replication algorithm, which we validated in a controlled experiment. Its proof-of-concept implementation showed that even in a geo-distributed configuration, replication throughput can scale with the number of nodes. Text messaging gateways often have a module for credit management, used when billing the senders for their traffic. In a multi-node environment the maintenance of the corresponding credit balances requires synchronization between the nodes, for which we designed and implemented an algorithm which uses less network traffic than existing solutions in many real-world situations.
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| 46. |
- Brehmer, Daniel, 1973-
(författare)
-
Support for mathematics teachers’ change : Examining catalysts for teacher learning and role of the teacher in professional development programmes
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When the perception changes regarding what mathematics students should be able to manage, this is typically addressed through a new national curriculum. To establish and implement this new curriculum in practice, teachers must be given the opportunity to change according to it. For such change, they need support in interpreting and implementing the new curriculum. Typically, there are two common ways to support teacher change: (1) developing and launching curriculum materials that correspond to the national curriculum; and (2) implementing professional development programmes (PDPs) that correspond to the new national curriculum. This thesis includes both aspects and aims to contribute to research on support for mathematics teachers’ change. This aim is operationalized by: (1) studying mathematics textbooks in which tasks and plausible teaching intentions are analysed; (2) studying teacher agency in collegial discussions in relation to the design of a PDP; and (3) mapping and describing catalysts for teacher learning from PDPs in research literature. These studies resulted in five papers, which are included in this thesis. The main results of the papers cover: the distribution of types of tasks in Swedish mathematics textbooks; the type of learning approach advocated in these textbooks; how different types of texts in PDPs relate to teacher agency in collegial discussions; and an identification and description of catalysts for teacher learning from PDPs for mathematics teachers. In the kappa1 of this thesis, these results are merged and discussed in relation to different models of teacher change. The focus in the kappa is on examining catalysts for teacher learning from such initiatives and the role of the teacher in PDPs. This examination suggests elaborations on parts of a conceptual framework for effective PDPs (Desimone, 2009). More precisely, the elaborations concern core critical features for effective PDPs, presented in this framework: Content Focus, Active Learning, Collective Participation, Duration, and Coherence. The main contributions of this thesis concern: a tool for analysing tasks in textbooks with respect to problem-solving tasks; an organizing frame for mapping learning catalysts from articles describing PDPs; a description of catalysts for teacher learning from PDPs as specifications of core critical features for effective PDPs; and the role of the teacher in PDPs as a catalyst for learning. Implications and suggestions for future research are discussed.___________________________1The Swedish term kappa will be used in this thesis in the absence of an equivalent English term for the introductory chapters of an aggregation dissertation
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| 47. |
- Bucaioni, Alessio, 1987-
(författare)
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A Model-driven Development Approach with Temporal Awareness for Vehicular Embedded Systems
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Considering the ubiquitousness of software in modern vehicles, its increased value and development cost, an efficient software development became of paramount importance for the vehicular domain. It has been identified that early verification of non functional properties of vehicular embedded software such as, timing, reliability and safety, is crucial to efficiency. However, early verification of non functional properties is hard to achieve with traditional software development approaches due to the abstraction and the lack of automation of these methodologies. This doctoral thesis aims at improving efficiency in vehicular embedded software development by minimising the need for late, expensive and time consuming software modifications with early design changes, identified through timing verification, which usually are cheaper and faster. To this end, we introduce a novel model-driven approach which exploits the interplay of two automotive-specific modelling languages for the representation of functional and execution models and defines a suite of model transformations for their automatic integration. Starting from a functional model (expressed by means of EAST-ADL), all the execution models (expressed by means of the Rubus Component Model) entailing unique timing configurations are derived. Schedulability analysis selects the set of the feasible execution models with respect to specified timing requirements. Eventually, a reference to the selected execution models along with their analysis results is automatically created in the related functional model to allow the engineer to investigate them. The main scientific contributions of this doctoral thesis are i) a metamodel definition for the Rubus Component Model, ii) an automatic mechanism for the generation of Rubus models from EAST-ADL, iii) an automatic mechanism for the selection and back-propagation of the analysis results and related Rubus models to design level and iv) a compact notation for visualising the selected Rubus models by means of a single execution model.
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| 48. |
- Bygde, Stefan, 1980-
(författare)
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Parametric WCET Analysis
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a real-time system, it is crucial to ensure that all tasks of the system hold their deadlines. A missed deadline in a real-time system means that the system has not been able to function correctly. If the system is safety critical, this could potentially lead to disaster. To ensure that all tasks keep their deadlines, the Worst-Case Execution Time (WCET) of these tasks has to be known.Static analysis analyses a safe model of the hardware together with the source or object code of a program to derive an estimate of the WCET. This estimate is guaranteed to be equal to or greater than the real WCET. This is done by making calculations which in all steps make sure that the time is exactly or conservatively estimated. In many cases, however, the execution time of a task or a program is highly dependent on the given input. Thus, the estimated worst case may correspond to some input or configuration which is rarely (or never) used in practice. For such systems, where execution time is highly input dependent, a more accurate timing analysis which take input into consideration is desired.In this thesis we present a method based on abstract interpretation and counting of semantic states of a program that gives a WCET in terms of some input to the program. This means that the WCET is expressed as a formula of the input rather than a constant. This means that once the input is known, the actual WCET may be more accurate than the absolute and global WCET. Our research also investigate how this analysis can be safe when arithmetic operations causes integers to wrap-around, where the common assumption in static analysis is that variables can take the value of any integer. Our method has been implemented as a prototype and as a part of a static WCET analysis tool in order to get experience with the method and to evaluate the different aspects. Our method shows that it is possible to obtain very complex and detailed information about the timing of a program, given its input.
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| 49. |
- Bäck, Per, 1987-
(författare)
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On Hom-associative Ore Extensions
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we introduce and study hom-associative Ore extensions. These are non-unital, non-associative, non-commutative polynomial rings in which the associativity condition is “twisted” by an additive group homomorphism. In particular, they are examples of hom-associative algebras, and they generalize the classical non-commutative polynomial rings introduced by Ore known as Ore extensions to the non-unital, hom-associative setting. At the same time, when the twisted associativity condition is null, they also generalize to the general non-unital, non-associative setting. We deduce necessary and sufficient conditions for hom-associative Ore extensions to exist, and construct concrete examples thereof. These include hom-associative generalizations of the quantum plane, the universal enveloping algebra of the two-dimensional non-abelian Lie algebra, and the first Weyl algebra, to name a few. The aforementioned algebras turn out to be formal hom-associative deformations of their associative counterparts, the latter two which cannot be formally deformed in the associative setting. Moreover, these are all weakly unital algebras, and we provide a way of embedding any multiplicative, non-unital hom-associative algebra into a multiplicative, weakly unital hom-associative algebra. This generalizes the classical unitalization of non-unital, associative algebras. We then study the hom-associative Weyl algebras in arbitrary characteristic, classify them up to isomorphism, and in the zero characteristic case, we prove that an analogue of the Dixmier conjecture is true. We also study hom-modules over hom-associative rings, and by doing so, we are able to prove a Hilbert's basis theorem for hom-associative Ore extensions. Our theorem includes as special cases both the classical Hilbert's basis theorem for Ore extensions and a Hilbert's basis theorem for unital, non-associative Ore extensions. Last, we construct examples of both hom-associative and non-associative Ore extensions which are all Noetherian by our theorem.
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| 50. |
- Cai, Simin
(författare)
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Systematic Design and Analysis of Customized Data Management for Real-Time Database Systems
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern real-time data-intensive systems generate large amounts of data that are processed using complex data-related computations such as data aggregation. In order to maintain logical data consistency and temporal correctness of the computations, one solution is to model the latter as transactions and manage them using a Real-Time Database Management System (RTDBMS). Ideally, depending on the particular system, the transactions are customized with the desired logical and temporal correctness properties, which should be enforced by the customized RTDBMS via appropriate transaction management mechanisms. However, developing such a data management solution with high assurance is not easy, partly due to inadequate support for systematic specification and analysis during the design. Firstly, designers do not have means to identify the characteristics of the computations, especially data aggregation, and to reason about their implications. Design flaws might not be discovered early enough, and thus they may propagate to the implementation. Secondly, meeting more properties simultaneously might not be possible, so trading-off the less critical ones for the critical one, for instance, temporal correctness, is sometimes required. Nevertheless, trade-off analysis of conflicting properties, such as transaction atomicity, isolation and temporal correctness, is mainly performed ad-hoc, which increases the risk of unpredictable behavior.In this thesis, we address the above problems by showing how to systematically design and provide assurance of transaction-based data management with data aggregation support, customized for real-time systems. We propose a design process as our methodology for the systematic design and analysis of the trade-offs between desired properties, which is facilitated by a series of modeling and analysis techniques. Our design process consists of three major steps as follows: (i) Specifying the data-related computations, as well as the logical data consistency and temporal correctness properties, from system requirements, (ii) Selecting the appropriate transaction models to model the computations, and deciding the corresponding transaction management mechanisms that can guarantee the properties, via formal analysis, and, (iii) Generating the customized RTDBMS with the proved transaction management mechanisms, via configuration or implementation. In order to support the first step of our process, we propose a taxonomy of data aggregation processes for identifying their common and variable characteristics, based on which their inter-dependencies can be captured, and the consequent design implications can be reasoned about. Tool support is provided to check the consistency of the data aggregation design specifications. To specify transaction atomicity, isolation and temporal correctness, as well as the transaction management mechanisms, we also propose a Unified Modeling Language (UML) profile with explicit support for these elements. The second step of our process relies on the systematic analysis of trade-offs between transaction atomicity, isolation and temporal correctness. To achieve this, we propose two formal frameworks for modeling transactions with abort recovery, concurrency control, and scheduling. The first framework UPPCART utilizes timed automata as the underlying formalism, based on which the desired properties can be verified by model checking. The second framework UPPCART-SMC models the system as stochastic timed automata, which allows for probabilistic analysis of the properties for large complex RTDBMS using statistical model checking. The encoding of high-level UTRAN specifications into corresponding formal models is supported by tool automation, which we also propose in this thesis. The applicability and usefulness of our proposed techniques are validated via several industrial use cases focusing on real-time data management.
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