| 1. |
- Adamson, Göran, 1958-
(författare)
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A Novel Method for Adaptive Control of Manufacturing Equipment in Cloud Environments
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ability to adaptively control manufacturing equipment, both in local and distributed environments, is becoming increasingly more important for many manufacturing companies.One important reason for this is that manufacturing companies are facing increasing levels of changes, variations and uncertainty, caused by both internal and external factors, which can negatively impact their performance. Frequently changing consumer requirements and market demands usually lead to variations in manufacturing quantities, product design and shorter product life-cycles. Variations in manufacturing capability and functionality, such as equipment breakdowns, missing/worn/broken tools and delays, also contribute to a high level of uncertainty. The result is unpredictable manufacturing system performance, with an increased number of unforeseen events occurring in these systems. Events which are difficult for traditional planning and control systems to satisfactorily manage.For manufacturing scenarios such as these, the use of real-time manufacturing information and intelligence is necessary to enable manufacturing activities to be performed according to actual manufacturing conditions and requirements, and not according to a pre-determined process plan. Therefore, there is a need for an event-driven control approach to facilitate adaptive decision-making and dynamic control capabilities.Another reason driving the move for adaptive control of manufacturing equipment is the trend of increasing globalization, which forces manufacturing industry to focus on more cost-effective manufacturing systems and collaboration within global supply chains and manufacturing networks. Cloud Manufacturing is evolving as a new manufacturing paradigm to match this trend, enabling the mutually advantageous sharing of resources, knowledge and information between distributed companies and manufacturing units. One of the crucial objectives for Cloud Manufacturing is the coordinated planning, control and execution of discrete manufacturing operations in collaborative and networked environments. Therefore, there is also a need that such an event-driven control approach supports the control of distributed manufacturing equipment.The aim of this research study is to define and verify a novel and comprehensive method for adaptive control of manufacturing equipment in cloud environments.The presented research follows the Design Science Research methodology. From a review of research literature, problems regarding adaptive manufacturing equipment control have been identified. A control approach, building on a structure of event-driven Manufacturing Feature Function Blocks, supported by an Information Framework, has been formulated. The Function Block structure is constructed to generate real-time control instructions, triggered by events from the manufacturing environment. The Information Framework uses the concept of Ontologies and The Semantic Web to enable description and matching of manufacturing resource capabilities and manufacturing task requests in distributed environments, e.g. within Cloud Manufacturing. The suggested control approach has been designed and instantiated, implemented as prototype systems for both local and distributed manufacturing scenarios, in both real and virtual applications. In these systems, event-driven Assembly Feature Function Blocks for adaptive control of robotic assembly tasks have been used to demonstrate the applicability of the control approach. The utility and performance of these prototype systems have been tested, verified and evaluated for different assembly scenarios.The proposed control approach has many promising characteristics for use within both local and distributed environments, such as cloud environments. The biggest advantage compared to traditional control is that the required control is created at run-time according to actual manufacturing conditions.The biggest obstacle for being applicable to its full extent is manufacturing equipment controlled by proprietary control systems, with native control languages. To take the full advantage of the IEC Function Block control approach, controllers which can interface, interpret and execute these Function Blocks directly, are necessary.
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| 2. |
- Aggestam, Lena
(författare)
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IT-supported Knowledge Repositories : Increasing their Usefulness by Supporting Knowledge Capture
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Organizations use various resources to achieve business objectives, and for financial gain. In modern business, knowledge is a critical resource, and organizations cannot afford not to manage it. Knowledge Management (KM) aims to support learning and to create value for the organization. Based on three levels of inquiry (why, what, how), work presented in this thesis includes a synthesized view of the existing body of knowledge concerning KM and hence a holistic characterization of KM. This characterization reveals a strong dependency between KM and Learning Organization (LO). Neither of them can be successful without the other. We show that a KM project resulting in an IT-supported knowledge repository is a suitable way to start when the intention is to initiate KM work. Thus, our research focuses on ITsupported knowledge repositories.Large numbers of KM projects fail, and organizations lack support for their KM undertakings. These are the main problems that our research addresses. In order for an IT-supported knowledge repository to be successful, it must be used. Thus, the content of the repository is critical for success. Our work reveals that the process of capturing new knowledge is critical if the knowledge repository is to include relevant and updated knowledge. With the purpose of supporting the capture process, this thesis provides a detailed characterization of the capture process as well as guidance aiming to facilitate the implementation of the capture process in such a way that knowledge is continuously captured, also after the KM implementation project is completed. We argue that the continuous capture of new knowledge which can potentially be stored in the knowledge repository will, in the long term perspective, have a positive influence on the usefulness of the repository. This will most likely increase the number of users of the repository and accordingly increase the number of successful KM projects.All the work presented in this thesis is the result of a qualitative research process comprising a literature review and an empirical study that were carried out in parallel. The empirical study is a case study inspired by action research, which involved participation in the project Efficient Knowledge Management and Learning in Knowledge Intensive Organizations (EKLär).
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| 3. |
- Alenljung, Beatrice
(författare)
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Envisioning a Future Decision Support System for Requirements Engineering : A Holistic and Human-centred Perspective
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Complex decision-making is a prominent aspect of requirements engineering (RE) and the need for improved decision support for RE decision-makers has been identified by a number of authors in the research literature. The fundamental viewpoint that permeates this thesis is that RE decision-making can be substantially improved by RE decision support systems (REDSS) based on the actual needs of RE decision-makers as well as the actual generic human decision-making activities that take place in the RE decision processes. Thus, a first step toward better decision support in requirements engineering is to understand complex decision situations of decision-makers. In order to gain a holistic view of the decision situation from a decision-maker’s perspective, a decision situation framework has been created. The framework evolved through an analysis of decision support systems literature and decision-making theories. The decision situation of RE decision-makers has been studied at a systems engineering company and is depicted in this thesis. These situations are described in terms of, for example, RE decision matters, RE decision-making activities, and RE decision processes. Factors that affect RE decision-makers are also identified. Each factor consists of problems and difficulties. Based on the empirical findings, a number of desirable characteristics of a visionary REDSS are suggested. Examples of characteristics are to reduce the cognitive load, to support creativity and idea generation, and to support decision communication. One or more guiding principles are proposed for each characteristic and available techniques are described. The purpose of the principles and techniques is to direct further efforts concerning how to find a solution that can fulfil the characteristic. Our contributions are intended to serve as a road map that can direct the efforts of researchers addressing RE decision-making and RE decision support problems. Our intention is to widen the scope and provide new lines of thought about how decision-making in RE can be supported and improved.
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| 4. |
- Alfredsson, Svante
(författare)
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Constitutive Behaviour and Fracture of Adhesive Layers : Inverse Methods and Energetic Balance
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the automobile industry, current demands on reduced emissions with maintained or even increased crash worthiness, forces the industry to seek weight-reducing designs. The possibility to use lightweight materials is obviously attractive. At joints, these lightweight materials have to be connected to high-strength or low-cost materials. In this context adhesive joining can provide a flexible solution. The method adds little weight to the structure, it allows for material combinations that are not possible to weld, and it provides increased stiffness to the structure as compared to the conventional spot-welding procedure. Moreover, electrolytic isolation of the multi-material joints is achieved. In this thesis, experimental methods are developed to determine the complete stress-deformation relation for an adhesive layer loaded in shear. Generally, the stress distribution is non-uniform in the test geometries used. Evaluation of experiments is performed using an inverse method. The idea is to measure the energy release rate as a function of the crack tip deformation. The stress-deformation relation is obtained by a subsequent differentiation. The method is shown to be capable of capturing the complete stress-deformation relation under stable loading conditions. A method to accurately determine the energy release rate is needed for the inverse method to be successful. A closed form expression for the energy release rate of the end-notch flexure adhesive joint specimen (ENF) is derived in this thesis. An approximate formula containing measurable quantities is also given. It is shown that both the applied load and the crack tip deformation are needed to determine the instantaneous value of the energy release rate of the ENF-specimen. Experimental results show that the influence of the crack tip deformation can be substantial. An alternative specimen is also analysed theoretically. An initial theoretical study on mixed mode fracture of adhesive layers is also given in this thesis. A detailed comparison is made of the mode-mixity obtained using two different, frequently used mechanical models; the beam/adhesive layer model, and the continuum model, i.e. a model neglecting the presence of the adhesive layer. It is tempting to assume that the two methods would produce similar results for the case of a thin adhesive layer. However, this is only the case for geometries which are materially and geometrically symmetric with respect to the adhesive layer. For asymmetric joints, on the other hand, the two models are found to predict fundamentally different values of the mode-mixity. Moreover, the mode-mixity of the beam/adhesive layer model is found to depend highly on the relative stiffness of the adherends and the adhesive layer. This dependency is found to be quantified through two parameters.
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| 5. |
- Alklind Taylor, Anna-Sofia, 1975-
(författare)
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Facilitation matters : A framework for instructor-led serious gaming
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis explores the use of serious games from an instructor perspective. More specifically, it aims to study the roles of instructors and how they can be facilitated within an instructor-led game-based training environment. Research within the field of serious games has mostly focused on the learners' perspective, but little attention has been paid to what the instructors do and what challenges that entails. In this thesis, I argue that serious games, as artefacts used for learning and training, cannot fully replace the instructors' tasks, but must rather be designed to facilitate the various activities of the instructors. Thus, instructors form an important target audience in serious game development – not just as subject matter experts, but also as users and players of the game – with a different set of needs than the learners. Moreover, serious gaming (the actualisation of a serious game) involves more than in-game activities, it also involves actions and events that occur off-game. These activities must also be considered when designing and utilising games for learning and training.Using a qualitative approach, instructor-led serious gaming has been explored from a range of contexts, from rehabilitation to incident commander training and military training. Several different instructor roles have been identified and characterised, including in-game facilitator, puckster, debriefer, technical support and subject matter expert. Based on empirical and theoretical material, a framework for instructor-led serious gaming has been developed. It involves best practices in different phases of game-based training, such as scenario authoring, coaching-by-gaming, assessing in-game and off-game performance, giving feedback, and conducting a debriefing or after-action review. Furthermore, specific needs and challenges for instructors have been identified and reformulated into guidelines for instructor-led serious gaming. The guidelines highlight the importance of usability and visualisation, as well as the need for carefully designed support tools for instructors' situation awareness, assessment and debriefing. Lastly, a number of success factors pertaining to both the development and actualisation of serious games are presented. Since serious games aim to be both productive and engaging, it is advantageous to work with interdisciplinary teams when developing serious games. This includes subject matter experts well versed in serious gaming practices. Furthermore, a successful serious game should adhere to sound pedagogical theories, be easy to use and maintain, and include system support for instructors' tasks. Successful serious gaming practices also involve having an organisational culture that fosters knowledge sharing among practitioners.
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| 6. |
- Amouzgar, Kaveh, 1980-
(författare)
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Metamodel Based Multi-Objective Optimization with Finite-Element Applications
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As a result of the increase in accessibility of computational resources and the increase of computer power during the last two decades, designers are able to create computer models to simulate the behavior of complex products. To address global competitiveness, companies are forced to optimize the design of their products and production processes. Optimizing the design and production very often need several runs of computationally expensive simulation models. Therefore, integrating metamodels, as an efficient and sufficiently accurate approximate of the simulation model, with optimization algorithms is necessary. Furthermore, in most of engineering problems, more than one objective function has to be optimized, leading to multi-objective optimization(MOO). However, the urge to employ metamodels in MOO, i.e., metamodel based MOO (MB-MOO), is more substantial.Radial basis functions (RBF) is one of the most popular metamodeling methods. In this thesis, a new approach to constructing RBF with the bias to beset a priori by using the normal equation is proposed. The performance of the suggested approach is compared to the classic RBF and four other well-known metamodeling methods, in terms of accuracy, efficiency and, most importantly, suitability for integration with MOO evolutionary algorithms. It has been found that the proposed approach is accurate in most of the test functions, and it was the fastest compared to other methods. Additionally, the new approach is the most suitable method for MB-MOO, when integrated with evolutionary algorithms. The proposed approach is integrated with the strength Pareto evolutionary algorithm (SPEA2) and applied to two real-world engineering problems: MB-MOO of the disk brake system of a heavy truck, and the metal cutting process in a turning operation. Thereafter, the Pareto-optimal fronts are obtained and the results are presented. The MB-MOO in both case studies has been found to be an efficient and effective method. To validate the results of the latter MB-MOO case study, a framework for automated finite element (FE) simulation based MOO (SB-MOO) of machining processes is developed and presented by applying it to the same metal cutting process in a turning operation. It has been proved that the framework is effective in achieving the MOO of machining processes based on actual FE simulations.
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| 7. |
- Anderberg, Peter
(författare)
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FACE : Disabled People, Technology and Internet
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on the Internet experiences of people withsignificant mobility/physical impairments who are proficient andexperienced computer users in their computer world but havelimitations in mobility that severely restrict their functioning inthe physical world. The Internet functioning of this group isanalysed by means of the factors attitude, control and enabling,with the main focus on what is achievable when all accessproblems such as unadapted interfaces, beginners’ difficulties andthe digital divide are overcome. If the virtual world is fullyavailable but the real world is not – what are the effects onlearning, self image, communities of practice, sense of coherence,power and control? What are the effects on peer-to-peer learningand co-operation? Independent living concepts and theoriesmanifest themselves throughout the thesis, most obviously,perhaps, in the selection of issues that are studied and in theperspectives.The theoretical background and concepts are those of disabilitystudies, with a social model and independent living perspective,and with strong influences from rehabilitation engineering anddesign.Throughout the thesis elaborations and clarifications of thepossibilities of interplay and co-existence between rehabilitationengineering and design and disability studies are made. Differentaspects of function design and technology are examined from anexpanded view on functioning, where technology is put in anindividual and social context with the FACE (Function – Attitude, Control, Enabling) tool.
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| 8. |
- Andersén, Annelie, 1977-
(författare)
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Ett särskilt perspektiv på högre studier? : Folkhögskoledeltagares sociala representationer om högskola och universitet
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Avhandlingen syftar till att undersöka folkhögskoledeltagares sociala representationer om högskola och universitet. Enligt teorin om sociala representationer är folkhögskoledeltagarnas sociala representationer om högskola och universitet något som skapas socialt och förändras beroende på deltagarnas erfarenheter av högskola och universitet. Avhandlingen syftar också till att undersöka dessa sociala representationers ursprung och framväxt, liksom om de har påverkats av andra sociala representationer exempelvis dem om folkhögskolans särart. För att identifiera folkhögskoledeltagarnas sociala identitet och sociala representationer har jag använt mig av empiriska data insamlat genom fria associationer och intervjuer med folkhögskoledeltagare och före detta folkhögskoledeltagare. För att undersöka representationernas ursprung har jag genomfört en dokumentstudie på folkhögskolelärarnas tidskrift. Resultaten visar att folkhögskolans företrädare genom hela folkhögskolans historia har förhållit sig till två huvudidéer, den om folkhögskolans särart och den om att folkhögskolan är en institution som anpassar sig efter det omkringliggande samhället och dess krav. Dessa båda idéer förklarar varför olika sociala identiteter och olika sociala representationer existerar bland folkhögskoledeltagarna. Grundidén att folkhögskolan har en särart leder till representationer om folkhögskolan som ett alternativ till annan utbildning och högskola och universitet som något som inte är likt folkhögskola. Den andra grundläggande idén om folkhögskolan som en institution som ständigt anpassar sig leder till representationer om folkhögskolan som en andra chans och högskolan som mål.
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| 9. |
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| 10. |
- Andersson, Erik
(författare)
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Det politiska rummet : villkor för situationspolitisk socialisation i en nätgemenskap av och för ungdomar
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim is to analyse the institutional character of, and the on-going communication in, a net community organised by and for young people. This is achieved using terms of conditions for situational political socialisation – a situation in a specific context in which the participants, within the battle between different groups attempting to organise society through interaction and action, adopt political preferences and skills. The thesis builds on agonism, a political theory in which controversy and struggle are viewed as prerequisites for human life that uses language as a political act. The net community, as an institution, contingently depends on political rebirth via action and communication. The use of language creates places that give the institution meaning while at the same time the institution claims the participants and their creation of meaning. Black Heart, the analysed net community, is a quasi-public space for and by young people aged between 14 and 28 years. It is a cultural community where political conversations take place among other kinds of communication. The institutional character of Black Heart and ten politically controversial conversations are analysed, using a case study method that applies web content analysis and computer mediated discourse analysis. There is a strong institutional framework operating in the political text conversations of Black Heart, the participants are governed by the institution and the participants govern each other. The political communication is characterised by revealing and arguing for political interest. To challenge is the dominant category of political action which constitutes political subjects that are offensive, argumentative and polemic. Political communication and the on-going interaction generate an educational situation in which the participants are expected to be content oriented, argumentative, expressive, communicative and polemic.
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