| 1. |
- Abghari, Shahrooz
(författare)
-
Data Mining Approaches for Outlier Detection Analysis
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Outlier detection is studied and applied in many domains. Outliers arise due to different reasons such as fraudulent activities, structural defects, health problems, and mechanical issues. The detection of outliers is a challenging task that can reveal system faults, fraud, and save people's lives. Outlier detection techniques are often domain-specific. The main challenge in outlier detection relates to modelling the normal behaviour in order to identify abnormalities. The choice of model is important, i.e., an unsuitable data model can lead to poor results. This requires a good understanding and interpretation of the data, the constraints, and requirements of the domain problem. Outlier detection is largely an unsupervised problem due to unavailability of labeled data and the fact that labeled data is expensive. In this thesis, we study and apply a combination of both machine learning and data mining techniques to build data-driven and domain-oriented outlier detection models. We focus on three real-world application domains: maritime surveillance, district heating, and online media and sequence datasets. We show the importance of data preprocessing as well as feature selection in building suitable methods for data modelling. We take advantage of both supervised and unsupervised techniques to create hybrid methods. More specifically, we propose a rule-based anomaly detection system using open data for the maritime surveillance domain. We exploit sequential pattern mining for identifying contextual and collective outliers in online media data. We propose a minimum spanning tree clustering technique for detection of groups of outliers in online media and sequence data. We develop a few higher order mining approaches for identifying manual changes and deviating behaviours in the heating systems at the building level. The proposed approaches are shown to be capable of explaining the underlying properties of the detected outliers. This can facilitate domain experts in narrowing down the scope of analysis and understanding the reasons of such anomalous behaviours. We also investigate the reproducibility of the proposed models in similar application domains.
|
|
| 2. |
- Acevedo, Carlos
(författare)
-
Developing Inclusive Innovation Processes and Co-Evolutionary University-Society Approaches in Bolivia
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study is part of a worldwide debate on inclusive innovation systems in developingcountries and particularly on the co-evolutionary processes taking place, seen from theperspective of a public university. The increasing literature that discusses how innovationsystems and development can foster more inclusive and sustainable societies hasinspired this thesis work. Thus, the main problem handled in the research concerns thequestion how socially sensitive research practices and policies at a public university inBolivia can be stimulated within emerging innovation system dynamics. In that vein,empirical knowledge is developed at the Universidad Mayor de San SimoÅLn (UMSS),Cochabamba as a contribution to experience-based learning in the field. Analysis arenourished by a dialogue with the work of prominent Latin American scholars andpractitioners around the idea of a developmental university and the democratizationof knowledge. The reader will be able to recognize a recursive transit between theoryand practice, where a number of relevant concepts are contextualized and connectedin order to enable keys of critical interpretation and paths of practices amplificationfor social inclusion purposes established. The study shows how, based on a previousexperience, new competences and capacities for the Technology Transfer Unit (UTT)at UMSS were produced, in this case transforming itself into a University InnovationCentre. Main lessons gained in that experience came from two pilot cluster development(food and leather sectors) and a multidisciplinary researchers network (UMSSInnovation Team) where insights found can improve future collaborative relations betweenuniversity and society for inclusive innovation processes within the Boliviancontext.
|
|
| 3. |
- Aeddula, Omsri, 1993-
(författare)
-
Navigating Data Challenges: AI-Driven Decision Support for Product-Service System Development
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solution providers are transitioning from product-centric models to service-oriented solutions. This shift has led to the rise of Product-Service Systems (PSS), which offer a holistic approach by integrating physical products with associated services. However, the inherent complexity and collaborative nature of PSS development present a significant challenge: information gathering, analysis, and knowledge building. This is further amplified in the early stages of PSS development due to data challenges such as uncertainty, ambiguity, and complexity. This complicates informed decision-making, potentially leading to the risk of sub-optimal outcomes and impacting the success of final offerings.This research proposes an AI-powered data analysis approach to address these data challenges and augment the decision-making process of PSS development. The focus is on supporting early-stage decision-making, as decisions made at this stage greatly impact the success of final solutions. The research investigates how data can be utilized and visualized to extract actionable insights, ultimately facilitating informed decision-making.The presented research demonstrates that AI-powered data analysis effectively supports informed decision-making in early-stage PSS development. By extracting actionable insights from complex data, handling data limitations, and enabling informed strategic decisions, knowledge sharing, and collaboration are facilitated among stakeholders. Furthermore, integrating AI with visualization tools fosters knowledge building and a deeper understanding of system behavior, ultimately leading to more successful PSS solutions. The efficacy of AI-powered data analysis for handling diverse data types across application domains is demonstrated, potentially leading to benefits such as a deeper understanding of system behavior and proactive solution strategies. These advancements contribute to developing decision support systems specifically for PSS development.Overall, this research demonstrates the efficacy of AI-powered data analysis in overcoming data challenges and empowering decision-makers in early-stage PSS development. This translates to more informed choices, leading to the creation of successful and efficient PSS solutions.
|
|
| 4. |
- Afzal, Wasif
(författare)
-
Search-Based Prediction of Software Quality : Evaluations and Comparisons
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Software verification and validation (V&V) activities are critical for achieving software quality; however, these activities also constitute a large part of the costs when developing software. Therefore efficient and effective software V&V activities are both a priority and a necessity considering the pressure to decrease time-to-market and the intense competition faced by many, if not all, companies today. It is then perhaps not unexpected that decisions that affects software quality, e.g., how to allocate testing resources, develop testing schedules and to decide when to stop testing, needs to be as stable and accurate as possible. The objective of this thesis is to investigate how search-based techniques can support decision-making and help control variation in software V&V activities, thereby indirectly improving software quality. Several themes in providing this support are investigated: predicting reliability of future software versions based on fault history; fault prediction to improve test phase efficiency; assignment of resources to fixing faults; and distinguishing fault-prone software modules from non-faulty ones. A common element in these investigations is the use of search-based techniques, often also called metaheuristic techniques, for supporting the V&V decision-making processes. Search-based techniques are promising since, as many problems in real world, software V&V can be formulated as optimization problems where near optimal solutions are often good enough. Moreover, these techniques are general optimization solutions that can potentially be applied across a larger variety of decision-making situations than other existing alternatives. Apart from presenting the current state of the art, in the form of a systematic literature review, and doing comparative evaluations of a variety of metaheuristic techniques on large-scale projects (both industrial and open-source), this thesis also presents methodological investigations using search-based techniques that are relevant to the task of software quality measurement and prediction. The results of applying search-based techniques in large-scale projects, while investigating a variety of research themes, show that they consistently give competitive results in comparison with existing techniques. Based on the research findings, we conclude that search-based techniques are viable techniques to use in supporting the decision-making processes within software V&V activities. The accuracy and consistency of these techniques make them important tools when developing future decision-support for effective management of software V&V activities.
|
|
| 5. |
- Ahmadi Mehri, Vida
(författare)
-
Towards Automated Context-aware Vulnerability Risk Management
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The information security landscape continually evolves with increasing publicly known vulnerabilities (e.g., 25064 new vulnerabilities in 2022). Vulnerabilities play a prominent role in all types of security related attacks, including ransomware and data breaches. Vulnerability Risk Management (VRM) is an essential cyber defense mechanism to eliminate or reduce attack surfaces in information technology. VRM is a continuous procedure of identification, classification, evaluation, and remediation of vulnerabilities. The traditional VRM procedure is time-consuming as classification, evaluation, and remediation require skills and knowledge of specific computer systems, software, network, and security policies. Activities requiring human input slow down the VRM process, increasing the risk of exploiting a vulnerability.The thesis introduces the Automated Context-aware Vulnerability Risk Management (ACVRM) methodology to improve VRM procedures by automating the entire VRM cycle and reducing the procedure time and experts' intervention. ACVRM focuses on the challenging stages (i.e., classification, evaluation, and remediation) of VRM to support security experts in promptly prioritizing and patching the vulnerabilities. ACVRM concept is designed and implemented in a test environment for proof of concept. The efficiency of patch prioritization by ACVRM compared against a commercial vulnerability management tool (i.e., Rudder). ACVRM prioritized the vulnerability based on the patch score (i.e., the numeric representation of the vulnerability characteristic and the risk), the historical data, and dependencies. The experiments indicate that ACVRM could rank the vulnerabilities in the organization's context by weighting the criteria used in patch score calculation. The automated patch deployment is implemented with three use cases to investigate the impact of learning from historical events and dependencies on the success rate of the patch and human intervention. Our finding shows that ACVRM reduced the need for human actions, increased the ratio of successfully patched vulnerabilities, and decreased the cycle time of VRM process.
|
|
| 6. |
- Al-Saedi, Ahmed Abbas Mohsin, 1980-
(författare)
-
Resource-Aware and Personalized Federated Learning via Clustering Analysis
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today’s advancement in Artificial Intelligence (AI) enables training Machine Learning (ML) models on the daily-produced data by connected edge devices. To make the most of the data stored on the device, conventional ML approaches require gathering all individual data sets and transferring them to a central location to train a common model. However, centralizing data incurs significant costs related to communication, network resource utilization, high volume of traffic, and privacy issues. To address the aforementioned challenges, Federated Learning (FL) is employed as a novel approach to train a shared model on decentralized edge devices while preserving privacy. Despite the significant potential of FL, it still requires considerable resources such as time, computational power, energy, and bandwidth availability. More importantly, the computational capabilities of the training devices may vary over time. Furthermore, the devices involved in the training process of FL may have distinct training datasets that differ in terms of their size and distribution. As a result of this, the convergence of the FL models may become unstable and slow. These differences can influence the FL process and ultimately lead to suboptimal model performance within a heterogeneous federated network.In this thesis, we have tackled several of the aforementioned challenges. Initially, a FL algorithm is proposed that utilizes cluster analysis to address the problem of communication overhead. This issue poses a major bottleneck in FL, particularly for complex models, large-scale applications, and frequent updates. The next research conducted in this thesis involved extending the previous study to include wireless networks (WNs). In WSNs, achieving energy-efficient transmission is a significant challenge due to their limited resources. This has motivated us to continue with a comprehensive overview and classification of the latest advancements in context-aware edge-based AI models, with a specific emphasis on sensor networks. The review has also investigated the associated challenges and motivations for adopting AI techniques, along with an evaluation of current areas of research that need further investigation. To optimize the aggregation of the FL model and alleviate communication expenses, the initial study addressing communication overhead is extended to include a FL-based cluster optimization approach. Furthermore, to reduce the detrimental effect caused by data heterogeneity among edge devices on FL, a new study of group-personalized FL models has been conducted. Finally, taking inspiration from the previously mentioned FL models, techniques for assessing clients' contribution by monitoring and evaluating their behavior during training are proposed. In comparison with the most existing contribution evaluation solutions, the proposed techniques do not require significant computational resources.The FL algorithms presented in this thesis are assessed on a range of real-world datasets. The extensive experiments demonstrated that the proposed FL techniques are effective and robust. These techniques improve communication efficiency, resource utilization, model convergence speed, and aggregation efficiency, and also reduce data heterogeneity when compared to other state-of-the-art methods.
|
|
| 7. |
- Andersén, Jimmie, 1981-
(författare)
-
Ett politiskt bygge : - översiktsplaneringens innehållsmässiga utveckling
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Debate often describes the evolution of spatial planning as a process of neo-liberalisation. However, this evolution has not been studied from the perspective of planning in general in Sweden. Whether comprehensive planning is also undergoing neo-liberalisation is considered here based on these overarching research questions: - To what extent has spatial planning undergone neo-liberalisation?- How can the evolution of comprehensive planning be understood as a neo-liberalisation process?Answering these questions requires an understanding of the content characterising this planning, and of what a neo-liberalisation process entails. To achieve such an understanding, this dissertation examines how planning in general can be understood as both a political control system and a market-based land use regime.The discourse of comprehensive planning was studied by analysing 17 comprehensive plans adopted in five municipalities over the 1989–2014 period.Generally, these plans follow a few main evolutionary paths. Municipal comprehensive planning has transitioned from being instrumental, encountering few problems, to becoming increasingly abstract and all-encompassing. Comprehensive planning increasingly concerns how growth is to be achieved locally. This change is occurring in both form and content. Change in form refers to the fact that comprehensive planning has been encompassing more and more subject areas over time, whereas change in content refers to the increasingly market-based content of such planning.The research question regarding the extent to which spatial planning is undergoing neo-liberalisation is answered by the obvious trend towards neo-liberalisation. This trend is not pervasive, as countervailing tendencies are also present. Spatial planning is thus becoming internally contradictory, with earlier values persisting, albeit often in interaction with new ones.The question of how comprehensive planning can be understood as a neo-liberalisation process has a three-part answer:- As content in comprehensive plans, neo-liberalisation can be understood as a focus on market rationality. - As form in comprehensive plans, neo-liberalisation can be understood as policy production with content that assumes an ever more neo-liberal orientation. Comprehensive planning during the studied period has come to include more and more municipal areas of activity.- From a neo-liberal perspective, neo-liberalisation is understood as economic utility maximisation.Planning is becoming increasingly neo-liberalised, but not neo-liberal. That this has occurred as a result of increasingly comprehensive policy formulations is somewhat surprising. We are faced with the politicisation of planning in general, which is increasingly informed by market-based policy. This trend represents a comprehensive policy shift towards more neo-liberal planning content, accompanied by more policies. More principles are appearing, addressing how planning and development are to proceed compared with the content of pre-existing plans. The neo-liberalisation process is thus occurring via means that are contradictory from a neo-liberal perspective.
|
|
| 8. |
- Andreasson, Eskil, 1976-
(författare)
-
Mechanics and Failure in Thin Material Layers : Towards Realistic Package Opening Simulations
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The final goal of this PhD-work is an efficient and user-friendly finite element modelling strategy targeting an industrial available package opening application. In order to reach this goal, different experimental mechanical and fracture mechanical tests were continuously refined to characterize the studied materials. Furthermore, the governing deformation mechanisms and mechanical properties involved in the opening sequence were quantified with full field experimental techniques to extract the intrinsic material response. An identification process to calibrate the material model parameters with inverse modelling analysis is proposed. Constitutive models, based on the experimental results for the two continuum materials, aluminium and polymer materials, and how to address the progressive damage modelling have been concerned in this work. The results and methods considered are general and can be applied in other industries where polymer and metal material are present. This work has shown that it is possible to select constitutive material models in conjunction with continuum material damage models, adequately predicting the mechanical behaviour in thin laminated packaging materials. Finally, with a slight modification of already available techniques and functionalities in a commercial general-purpose finite element software, it was possible to build a simulation model replicating the physical behaviour of an opening device. A comparison of the results between the experimental opening and the virtual opening model showed a good correlation.The advantage with the developed modelling approach is that it is possible to modify the material composition of the laminate. Individual material layers can be altered, and the mechanical properties, thickness or geometrical shape can be changed. Furthermore, the model is flexible and a new opening design with a different geometry and load case can easily be implemented and changed in the simulation model. Therefore, this type of simulation model is prepared to simulate sustainable materials in packages and will be a useful tool for decision support early in the concept selection in technology and development projects.
|
|
| 9. |
- Andrén, Linus
(författare)
-
Active suppression of vibration and noise in industrial applications
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today, active control technology is about to emerge from the research labs into products in various areas. It has become an attractive method where passive techniques have low impact at low frequencies and adding active control to that part is often an attractive solution. The active control technique has been enabled by the rapid development of digital signal processors over the last decades. The focal point in this thesis is active vibration and noise suppression. Two different industrial applications have been subjected to active control to reduce unwanted disturbances. In cutting operations, active vibration suppression has been applied to both external turning and boring operations with successful results. Turning operations, and in particular boring operations, are typical examples of chatter prone machining. In order to implement active vibration control in boring operations a thourough investigation of the boring process has been made in the first two parts in this thesis. The following two parts of the thesis treat active vibration suppression in external turning operations and in boring operations. The second industrial application treats the noise in a fork-lift truck. In the final part of the thesis, active noise suppression has been implemented in the cabin of a fork-lift truck.
|
|
| 10. |
- Ankre, Rosemarie, 1975-
(författare)
-
Friluftslivkonflikter i svenska kustlandskap ur ett planerings- och användarperspektiv : Studier av Luleå och Blekinge skärgårdar
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hav och kust har alltid varit viktiga för oss människor. I svenska kustlandskap har boende, infrastruktur och fiskenäring existerat sedan lång tid tillbaka samtidigt som områdena också varit viktiga för nöje och rekreation. Men mellan olika intressen, samt mellan och inom olika användargrupper samt förvaltning, kan det uppstå målkonflikter. Utgångspunkten för den här avhandlingen är att beskriva och analysera eventuella målkonflikter kopplat till friluftsliv utifrån både ett planerings- och ett användarperspektiv genom två fallstudier i Luleå och Blekinge skärgårdar. Friluftslivet är en del av samhället och dess relevans för fysisk och mental återhämtning ger planering och förvaltning av friluftsliv ett ökat politiskt stöd, samtidigt som tidigare forskning visat att friluftsliv är stark i retoriken - men svag i planeringspraktiken. Därför behövs kunskap som kan utveckla planering och förvaltning av friluftsliv i svenska kustlandskap.Resultaten från den här avhandlingen visar att användarnas perspektiv på målkonflikter i Luleå och Blekinge skärgårdar ännu inte till stora delar har inkluderats i den kommunala planeringen. En slutsats är alltså att det finns skillnader i hur konflikter i samband med friluftsliv beskrivs och identifieras i den fysiska planeringen jämfört med användarnas upplevelser. Det har betydelse för förståelsen av friluftlivskonflikter och hanteringen av dessa. Förutom analys och diskussion av konflikter kopplat till friluftsliv, ingår en fördjupande studie av buller och tystnad som konflikt. Upplevelserna av lugn och ro samt tystnad är centrala för användarna i Luleå och Blekinge skärgårdar. Ett problem som avslöjas är att metoder med decibelnivåer inte avgör skillnader i buller som upplevelse i sig. Upplevelsen av buller och tystnad är nämligen subjektiv. Även zonering undersöks som ett planerings- och förvaltningsverktyg för att hantera friluftslivkonflikter i svenska kustlandskap. Som denna avhandling visar, finns det flertalet exempel på olika sorters zonering i Luleå och Blekinge skärgårdar. När man i planering och förvaltning utgår från ett perspektiv där naturvård och bevarande är utgångspunkterna, så måste ytterligare värderingar och verktyg inbegripas som att inkludera användare med deras olika behov, upplevelser och aktiviteter som äger rum i skärgårdarnas landskap. Att landskapet i sig är av betydelse syns också i resultaten. I fallstudiernas översiktsplaner markeras det värdefulla, attraktiva och unika med skärgårdslandskapet, medan användarna betonar det äkta, naturliga och opåverkade landskapet som grund för deras friluftsupplevelser.Den här avhandlingen tillför kunskap om spänningen mellan olika attityder och synsätt i den fysiska planeringens processer, förvaltning samt friluftslivets användare i svenska kustlandskap. Avhandlingen är också ett tillägg till tidigare kunskap om zonering som ett sätt att hantera konflikter i svenska kustlandskap, där särskilt användarperspektivet är en viktig del. Avhandlingen bidrar även till en grundläggande översikt av fysisk planering i relation till friluftsliv.
|
|
