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  • 1.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Holm, Magnus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Moore, Philip
    Academy of Innovation & Research, Falmouth University, Cornwall, United kingdom.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. KTH Royal Institute of Technology, Stockholm, Sweden.
    A Cloud Service Control Approach for Distributed and Adaptive Equipment Control in Cloud Environments2016Inngår i: Research and Innovation in Manufacturing: Key Enabling Technologies for the Factories of the Future - Proceedings of the 48th CIRP Conference on Manufacturing Systems / [ed] Roberto Teti, Elsevier, 2016, Vol. 41, s. 644-649Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A developing trend within the manufacturing shop-floor domain is the move of manufacturing activities into cloud environments, as scalable, on-demand and pay-per-usage cloud services. This will radically change traditional manufacturing, as borderless, distributed and collaborative manufacturing missions between volatile, best suited groups of partners will impose a multitude of advantages. The evolving Cloud Manufacturing (CM) paradigm will enable this new manufacturing concept, and on-going research has described many of its anticipated core virtues and enabling technologies. However, a major key enabling technology within CM which has not yet been fully addressed is the dynamic and distributed planning, control and execution of scattered and cooperating shop-floor equipment, completing joint manufacturing tasks.

    In this paper, the technological perspective for a cloud service-based control approach is described, and how it could be implemented. Existing manufacturing resources, such as soft, hard and capability resources, can be packaged as cloud services, and combined to create different levels of equipment or manufacturing control, ranging from low-level control of single machines or devices (e.g. Robot Control-as-a-Service), up to the execution of high level multi-process manufacturing tasks (e.g. Manufacturing-as-a-Service). A multi-layer control approach, featuring adaptive decision-making for both global and local environmental conditions, is proposed. This is realized through the use of a network of intelligent and distributable decision modules such as event-driven Function Blocks, enabling run-time manufacturing activities to be performed according to actual manufacturing conditions. The control system’s integration to the CM cloud service management functionality is also described.

  • 2.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Royal Institute of Technology, Stockholm, Sweden.
    Holm, Magnus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Moore, Philip
    Falmouth University, Cornwall, UK.
    Adaptive Robot Control as a Service in Cloud Manufacturing2015Inngår i: ASME 2015 International Manufacturing Science and Engineering Conference: Volume 2: Materials; Biomanufacturing; Properties, Applications and Systems; Sustainable Manufacturing, ASME Press, 2015, Vol. 2, s. Paper No. MSEC2015-9479-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The interest for implementing the concept of Manufacturing-as-a-Service is increasing as concepts for letting the manufacturing shop-floor domain take advantage of the cloud appears. Combining technologies such as Internet of Things, Cloud Computing, Semantic Web, virtualisation and service-oriented technologies with advanced manufacturing models, information and communication technologies, Cloud Manufacturing (CM) is emerging as a new manufacturing paradigm. The ideas of on-demand, scalable and pay-for-usage resource-sharing in this concept will move manufacturing towards distributed and collaborative missions in volatile partnerships. This will require a control approach for distributed planning and execution of cooperating manufacturing activities. Without control based on both global and local environmental conditions, the advantages of CM will not be fulfilled.

    By utilising smart and distributable decision modules such as event-driven FBs, run-time manufacturing operations in a distributed environment may be adjusted to prevailing manufacturing conditions. Packaged in a cloud service for manufacturing equipment control, it will satisfy the control needs in CM. By combining different resource types, such as hard, soft and capability resources, the cloud service Robot Control-as-a-Service can be realised.

    This paper describes the functional perspective and enabling technologies for a control approach for robotic assembly tasks in CM, and describes a scenario for its implementation.

  • 3.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Kungliga Tekniska Högskolan, Stockholm (KTH).
    Holm, Magnus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Moore, Philip
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Academy for Innovation & Research, Falmouth University, UK.
    Adaptive Robotic Control in Cloud Environments2014Inngår i: Proceedings of the 24th International Conference on Flexible Automation and Intelligent Manufacturing / [ed] F. Frank Chen, The University of Texas at San Antonio, U.S.A., Lancaster, Pennsylvania, USA: DEStech Publications, Inc , 2014, s. 37-44Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The increasing globalization is a trend which forces manufacturing industry of today to focus on more cost-effective manufacturing systems and collaboration within global supply chains and manufacturing networks. Cloud Manufacturing (CM) 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. Providing a framework for collaboration within complex and critical tasks, such as manufacturing and design, it increases the companies’ ability to successfully compete on a global marketplace. One of the major, crucial objectives for CM is the coordinated planning, control and execution of discrete manufacturing operations in a collaborative and networked environment. This paper describes the overall concept of adaptive Function Block control of manufacturing equipment in Cloud environments, with the specific focus on robotic assembly operations, and presents Cloud Robotics as “Robot Control-as-a-Service” within CM.

  • 4.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Department of Production Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Holm, Magnus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Moore, Philip
    Academy for Innovation & Research, Falmouth University, Cornwall, United Kingdom.
    Cloud Manufacturing: A Critical Review of Recent Development and Future Trends2017Inngår i: International journal of computer integrated manufacturing (Print), ISSN 0951-192X, E-ISSN 1362-3052, Vol. 30, nr 4-5, s. 347-380Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is an on-going paradigm shift in manufacturing, in which modern manufacturing industry is changing towards global manufacturing networks and supply chains. This will lead to the flexible usage of different globally distributed, scalable and sustainable, service-oriented manufacturing systems and resources. Combining recently emerged technologies, such as Internet of Things, Cloud Computing, Semantic Web, service-oriented technologies, virtualisation and advanced high-performance computing technologies, with advanced manufacturing models and information technologies, Cloud Manufacturing is a new manufacturing paradigm built on resource sharing, supporting and driving this change.

    It is envisioned that companies in all sectors of manufacturing will be able to package their resources and know-hows in the Cloud, making them conveniently available for others through pay-as-you-go, which is also timely and economically attractive. Resources, e.g. manufacturing software tools, applications, knowledge and fabrication capabilities and equipment, will then be made accessible to presumptive consumers on a worldwide basis.

    Cloud Manufacturing has been in focus for a great deal of research interest and suggested applications during recent years, by both industrial and academic communities. After surveying a vast array of available publications, this paper presents an up-to-date literature review together with identified outstanding research issues, and future trends and directions within Cloud Manufacturing.

  • 5.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Royal Institute of Technology, Stockholm, Sweden.
    Holm, Magnus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Moore, Philip
    Falmouth University, Cornwall, United Kingdom.
    Feature-Based Adaptive Manufacturing Equipment Control for Cloud Environments2016Inngår i: Proceedings of the ASME 11th International Manufacturing Science and Engineering Conference, 2016, vol 2, American Society of Mechanical Engineers (ASME) , 2016, artikkel-id UNSP V002T04A019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The ideas of on-demand, scalable and pay-for-usage resource-sharing in Cloud Manufacturing are steadily attracting more interest. For implementing the concept of Manufacturing as-a-Service in a cloud environment, description models and implementation language for resources and their capabilities are required. A standardized approach for systemived virtualization, servisilisation, retrieval, selection and composition into higher levels of functionality is necessary. For the collaborative sharing and use of networked manufacturing resources there is also a need for a control approach for distributed manufacturing equipment. In this paper, the technological perspective for an adaptive cloud service-based control approach is described, and a supporting information model for its implementation. The control is realized through the use of a network of intelligent and distributable Function Block decision modules, enabling run-time manufacturing activities to be performed according to actual manufacturing conditions. The control system's integration to the cloud service management functionality is described, as well as a feature-level capability model and the use of ontologies and the Semantic Web.

  • 6.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Kungliga Tekniska Högskolan, Stockholm (KTH).
    Holm, Magnus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Moore, Philip
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Academy for Innovation & Research, Falmouth University, UK.
    Function Block Approach for Adaptive Robotic Control in Virtual and Real Environments2014Inngår i: Proceedings of the 14th Mechatronics Forum International Conference / [ed] Leo J. De Vin and Jorge Solis, Karlstad: Karlstads universitet, 2014, s. 473-479Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Many manufacturing companies are facing an increasing amount of changes and uncertainty, caused by both internal and external factors. Frequently changing customer and market demands lead to variations in manufacturing quantities, product design and shorter product life-cycles, and variations in manufacturing capability and functionality 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. Such events are difficult for traditional planning and control systems to satisfactorily manage. For scenarios like these, with a dynamically changing manufacturing environment, adaptive decision making is crucial for successfully performing manufacturing operations. Relying on real-time information of manufacturing processes and operations, and their enabling resources, adaptive decision making can be realized with a control approach combining IEC 61499 event-driven Function Blocks (FBs) with manufacturing features. These FBs are small decision-making modules with embedded algorithms designed to generate the desired equipment control code. When dynamically triggered by event inputs, parameter values in their data inputs are forwarded to the appropriate algorithms, which generate new events and data output as control instructions. The data inputs also include monitored real-time information which allows the dynamic creation of equipment control code adapted to the actual run-time conditions on the shop-floor. Manufacturing features build on the concept that a manufacturing task can be broken down into a sequence of minor basic operations, in this research assembly features (AFs). These features define atomic assembly operations, and by combining and implementing these in the event-driven FB embedded algorithms, automatic code generation is possible. A test case with a virtual robot assembly cell is presented, demonstrating the functionality of the proposed control approach.

  • 7.
    Adamson, Göran
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Wang, Lihui
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Department of Production Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Moore, Philip
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Feature-based control and information framework for adaptive and distributed manufacturing in cyber physical systems2017Inngår i: Journal of manufacturing systems, ISSN 0278-6125, E-ISSN 1878-6642, Vol. 43, s. 305-315Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modern distributed manufacturing within Industry 4.0, supported by Cyber Physical Systems (CPSs), offers many promising capabilities regarding effective and flexible manufacturing, but there remain many challenges which may hinder its exploitation fully. One major issue is how to automatically control manufacturing equipment, e.g. industrial robots and CNC-machines, in an adaptive and effective manner. For collaborative sharing and use of distributed and networked manufacturing resources, a coherent, standardised approach for systemised planning and control at different manufacturing system levels and locations is a paramount prerequisite.

    In this paper, the concept of feature-based manufacturing for adaptive equipment control and resource-task matching in distributed and collaborative CPS manufacturing environments is presented. The concept has a product perspective and builds on the combination of product manufacturing features and event-driven Function Blocks (FB) of the IEC 61499 standard. Distributed control is realised through the use of networked and smart FB decision modules, enabling the performance of collaborative run-time manufacturing activities according to actual manufacturing conditions. A feature-based information framework supporting the matching of manufacturing resources and tasks, as well as the feature-FB control concept, and a demonstration with a cyber-physical robot application, are presented.

  • 8.
    Adawi, Rahim
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Preventing fatal effects of overworking: Product design solution2018Independent thesis Basic level (university diploma), 20 poäng / 30 hpOppgave
    Abstract [en]

    “Overworking to death” is a phenomenon that has been noticeable in developing countries. The cause of death is mainly through ischemic strokes. While the victims’ occupations differed, they all shared a common characteristic, being positioned in a sedentary work, ranging from IT workers to doctors. This project’s aim was to develop a product that prevented or decreased the strokes that derived from sedentary overwork. This was mainly tackled by preventing one of the three causes of developing blood props, slowed blood flow. In order to gather rich data of the phenomenon, a qualitative study was conducted in China, during two months. By doing an extensive structured sampling, information rich data could be gathered during a short period of time. Data were derived from observations, questionnaires and an interview, which then was interpreted to customer needs and the final product specification. The final product became a trouser with an in built dynamic compression mechanic, that can compress the veins mostly during sitting activities, in order to prevent blood stasis. The compression mechanic works like the Chinese finger trap; compressing the calves while sitting and stretching the legs forward. It is made only out of polysaccharides fibres; cotton and corn.

  • 9.
    Ahmed, Adell
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Analys och simulering av produktionsflödet på ett tillverkningsföretag: Simulering kombinerat med Lean-principer2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Konkurrensen mellan tillverkningsföretag ökar ständigt på grund av nya produktionskrav och en efterfrågan på massproducerade varor som är kundanpassade. För att kunna möta kundernas krav måste företagen öka anpassningen av sin produktion utan att förlora kvalitet. Som en följd av en ökad produktion inom verkstaden undersöker nu det uppdragsgivande företaget som deltar i detta projekt, tanken att investera i en automatiserad hydraulisk press för att centralisera processen utanför de olika monteringslinjerna.

    Syftet med examensarbetet är att undersöka om en framtida statorpress kan klara av att försörja fyra monteringslinjer med material. Ett av kraven på det nya upplägget är att årsvolymen ska öka med 50 %.

    Den övergripande arbetsmetod som använts i detta projekt är baserad på Lean-, simulerings- och optimeringsmetoder. För att få en översikt över problemet har en nulägesanalys på det nuvarande flödet gjorts. Därefter gjordes en datainsamling genom dialoger med berörd personal, observationer och studier av historisk data som samlats in. Den insamlade datan användes för att analysera systemet och som input för simuleringsmodellen som skapades över det framtida flödet. För att analysera och förbättra systemet har olika Lean-verktyg använts under projektets gång.

    Företaget presenterade även sina idéer om hur de ville att det tänkta flödet skulle se ut. Dessa har sedan vidareutvecklats och legat till grund för de förbättringsförslag som presenterats. Ett krav var att lösningsförslaget skulle vara Lean-inspirerat.

    Syftet med studien uppnåddes genom att skapa en simuleringsmodell för att testa hur systemet beter sig under olika förhållanden. Det första scenariot som skapades var ett Pull-flöde där produkterna tillverkades endast när det uppstod ett behov. Det andra scenariot var ett Push- system där ingen hänsyn togs till Just-In-Time.

    Resultatet från scenarierna visade en tydlig skillnad mellan de två scenarierna. Pull-flödet visade sig vara mer lämpligt eftersom antalet Produkter I Arbete och ledtiden då minskade drastiskt. Lösningsförslaget med Kanbanmetoden och ett förslag på utformningen av det framtida flödet presenterades även i rapporten.

  • 10.
    Al-Dabagh, Hussain
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Wahlström, Daniel
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Konstruktion av gripverktyg för en kollaborativ robot2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Detta arbete utförs för att använda en kollaborativ robot i en monteringsprocess med målet att lösa en typ av dold montering, där kugghjul ska synkroniseras. Eftersom delarna är ömtåliga och tunga blir de svåra för montören att hantera, vilket kan leda till skador på material eller ännu värre på montören. Ett gripverktyg ska därför konstrueras för att användas med en kollaborativ robot vid denna typ av montering. En jämförelse av kollaborativa robotar utförs, utifrån två nödvändiga krav,  där robotens lyftförmåga måste vara minst 10 kg och att robotarna säkerhetsmässigt uppfyller säkerhetsstandarder. Där coboten KUKA LBR IIWA 14 visas uppfylla dessa krav och anses vara lämpligast till att utföra arbetsuppgiften. Roboten har en lyftförmåga på 14 kg, vilket betyder att den klarar av gripverktyget och transmissionskåpans massa, roboten anses också vara väldigt enkel att programmera. LBR iiwa är en väldigt mångsidig robot och har inte några stora brister och därför anses valet av robot vara väl genomfört. Ett gripverktyg har konstruerats och gått igenom olika utvecklingsfaser, från att konceptgenerera idéer på designen till att välja material och göra FEM-analyser. Resultat antyder att val av design och material på gripverktyget gör att den är godkänd för tillverkning och kommer att klara av belastningarna gripverktyget kommer att utsättas för vid utförandet av arbetsuppgiften.

  • 11.
    Alfredsson, Henrik
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Kyngäs, Johanni
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Simuleringsmodell för kontroll av färdigvarulagers storlek2014Independent thesis Basic level (university diploma), 15 poäng / 22,5 hpOppgave
  • 12.
    Alfredsson, K. Svante
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    On the determination of constitutive properties of adhesive layers loaded in shear - an inverse solution2003Inngår i: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 123, nr 1-2, s. 49-62Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method to determine constitutive properties of thin adhesive layers loaded in shear is presented. The test specimen consists of two adherends joined by the adhesive layer. By loading the specimen antisymmetrically with respect to the adhesive layer a state of pure shear is ensured. To avoid instability the test specimen is designed to give a non-uniform stress distribution in the adhesive layer. This is achieved by using a long specimen loaded at one side. The method is based on an exact inverse solution which is derived utilizing the balance of the energetic forces of the applied loads and of the adhesive at the start of the adhesive layer. The method is intended for determination of both hardening and softening behaviour of adhesives but is confined to monotonic loading

  • 13.
    Alfredsson, K. Svante
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Biel, Anders
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Salimi, Saeed
    Högskolan i Skövde.
    Shear testing of thick adhesive layers using the ENF-specimen2015Inngår i: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 62, s. 130-138Artikkel i tidsskrift (Fagfellevurdert)
  • 14.
    Allert, Anna-Lena
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Säfsten, Kristina
    School of Engineering, Jönköping University, Jönköping, Sweden.
    Business Support Agencies introducing Lean Production in SMEs - Does it make any difference?2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Many SMEs are implementing lean production in collaboration with a business support agency in order to improve their competitiveness. This research investigated whether improvement initiatives had the intended effect in some companies. A questionnaire was answered by employees in 26 SMEs. The result indicated experienced effect concerning leadership, communication and employee commitment, areas considered important for success in improvement initiatives,   and also progress in areas that characterise development towards lean. The result also indicated differences in experienced effect between managerial and non-managerial functions and between companies. 

  • 15.
    Amenabar, Leire
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Carreras, Leire
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Augmented Reality Framework for Supporting and Monitoring Operators during Maintenance Operations in Industrial Environments2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    In an ever-changing and demanding world where short assembly and innovation times are indispensable, it is of paramount importance to ensure that the machinery used throughout the whole process of a product are in their best possible condition. This guarantees that the performance of each machine will be optimal, and hence, the process times will be the shortest possible, while the best quality products are obtained. Moreover, having a machine in an impeccable status permits making the necessary changes to it, in order to fulfil the requirements that a more advanced or complex product may have. Maintenance operations and their corresponding trainings have historically been time-consuming, and a vast amount of information has been transmitted from an expert to a newer operator. This means that there has been the need of working with experienced operators to secure that a good service is provided. However, different technologies like augmented reality (AR) have been shown to have a positive impact in the support and monitoring of operators in industrial maintenance operations.The present project gathers information in regard to the framework of AR, with the aim of supporting and monitoring operators in industrial environments. The proposed method consists on the development of an artefact, which would lead to a possible improvement of the already existing solutions. It is believed that the development of an AR application could grant the necessary aid to any operator in maintenance operations. The result of this suggestion is an AR application which superimposes visual information on the physical equipment.

  • 16.
    Amouzgar, Kaveh
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Metamodel Based Multi-Objective Optimization with Finite-Element Applications2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    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.

  • 17.
    Amouzgar, Kaveh
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Andersson, Tobias J.
    Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    A framework for simulation based multi-objective optimization and knowledge discovery of machining process2018Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 98, nr 9-12, s. 2469-2486Artikkel i tidsskrift (Fagfellevurdert)
  • 18.
    Amouzgar, Kaveh
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Andersson, Tobias J.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Metamodel based multi-objective optimization of a turning process by using finite element simulationInngår i: Simulation Modelling Practice and Theory, ISSN 1569-190XArtikkel i tidsskrift (Fagfellevurdert)
  • 19.
    Amouzgar, Kaveh
    et al.
    Högskolan i Skövde, Forskningscentrum för Virtuella system. Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Radial basis functions with a priori bias as surrogate models: A comparative study2018Inngår i: Engineering applications of artificial intelligence, ISSN 0952-1976, E-ISSN 1873-6769, Vol. 71, s. 28-44Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Radial basis functions are augmented with a posteriori bias in order to perform robustly when used as metamodels. Recently, it has been proposed that the bias can simply be set a priori by using the normal equation, i.e., the bias becomes the corresponding regression model. In this study, we demonstrate the performance of the suggested approach (RBFpri) with four other well-known metamodeling methods; Kriging, support vector regression, neural network and multivariate adaptive regression. The performance of the five methods is investigated by a comparative study, using 19 mathematical test functions, with five different degrees of dimensionality and sampling size for each function. The performance is evaluated by root mean squared error representing the accuracy, rank error representing the suitability of metamodels when coupled with evolutionary optimization algorithms, training time representing the efficiency and variation of root mean squared error representing the robustness. Furthermore, a rigorous statistical analysis of performance metrics is performed. The results show that the proposed radial basis function with a priori bias achieved the best performance in most of the experiments in terms of all three metrics. When considering the statistical analysis results, the proposed approach again behaved the best, while Kriging was relatively as accurate and support vector regression was almost as fast as RBFpri. The proposed RBF is proven to be the most suitable method in predicting the ranking among pairs of solutions utilized in evolutionary algorithms. Finally, the comparison study is carried out on a real-world engineering optimization problem. © 2018 Elsevier Ltd

  • 20.
    Amouzgar, Kaveh
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system. Product Development Department, School of Engineering, Jönköping University, Jönköping, Sweden.
    Strömberg, Niclas
    Department of Mechanical Engineering, School of Science and Technology, University of Örebro, Sweden.
    Radial basis functions as surrogate models with a priori bias in comparison with a posteriori bias2017Inngår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 55, nr 4, s. 1453-1469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to obtain a robust performance, the established approach when using radial basis function networks (RBF) as metamodels is to add a posteriori bias which is defined by extra orthogonality constraints. We mean that this is not needed, instead the bias can simply be set a priori by using the normal equation, i.e. the bias becomes the corresponding regression model. In this paper we demonstrate that the performance of our suggested approach with a priori bias is in general as good as, or even for many test examples better than, the performance of RBF with a posteriori bias. Using our approach, it is clear that the global response is modelled with the bias and that the details are captured with radial basis functions. The accuracy of the two approaches are investigated by using multiple test functions with different degrees of dimensionality. Furthermore, several modeling criteria, such as the type of radial basis functions used in the RBFs, dimension of the test functions, sampling techniques and size of samples, are considered to study their affect on the performance of the approaches. The power of RBF with a priori bias for surrogate based design optimization is also demonstrated by solving an established engineering benchmark of a welded beam and another benchmark for different sampling sets generated by successive screening, random, Latin hypercube and Hammersley sampling, respectively. The results obtained by evaluation of the performance metrics, the modeling criteria and the presented optimal solutions, demonstrate promising potentials of our RBF with a priori bias, in addition to the simplicity and straight-forward use of the approach.

  • 21.
    Ander, Jenny
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Johansson, Matilda
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Utveckling av laddhandske för laddbara fordon2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Under höstterminen 2017 har Jenny Ander och Matilda Johansson utfört ett projekt tillsammans med Sea Ice AB i kursen Examensarbete i Integrerad produktutveckling vid Högskolan i Skövde. Sea Ice AB arbetar med att utveckla ladd-infrastruktursystem för laddbara fordon med fokus på nytta för slutanvändaren, hög kvalitét samt öka hållbarheten för miljön.Företaget satsar på att växa sig större på marknaden och i framtiden kunna leverera attraktiva produkter och tjänster, vilket i detta projekt inneburit utveckling av en ny laddhandske för laddbara fordon.Under projektet har laddhandskar samt CEE-don jämförts med varandra med fokus på dess inre komponenter. Förstudien grundar sig bland annat i en litteraturstudie där standarder studerats, ergonomi- och användarstudier, enkätutskick, elektriska mätningar, men främst demontering och undersökning av laddhandskar samt CEE-don.Efter förstudien påbörjades konceptutvecklingen av laddhandsken tillsammans med designmetoder, FEM-analyser, CAD- och lermodellering, konceptsållning och detaljdesign. Konceptutvecklingen resulterade i ett fullständigt slutkoncept både för invändiga komponenter, men också ett utvändigt skal med ergonomiska greppytor och vinklar.Den slutliga laddhandsken har jämförts mot kravspecifikationen och uppnått de krav som var satta inför projektet, med viss reservation för fortsatt utveckling. Laddhandsken har ett unikt och tilltalande utseende och uppfyller de önskemål som både användarna och Sea Ice AB efterfrågat.

  • 22.
    Andersson, Emil
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Optimization and re-design of a wheel hub to reduce unsprung mass of a rallycross car2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Wheel Hub of a rallycross car is analysed to reduce the unsprung mass of the car. The problem statement is to mainly focus on the unsprung mass related to the suspension, and more specifically on the Wheel Hub. One of the objectives of the suspension system of a car is to damping the movement of the car. This is an important area when designing a vehicle, and especially a race car due to the extreme conditions that may result in reduced traction and loose of confidence for the driver. A theoretical model is performed to demonstrate the importance of a low unsprung mass and to illustrate how it affects the vehicle-handling. A process to evaluate the current Wheel Hub and decision to re-design the Wheel Hub is performed, and the parts are analysed using the Finite Element Method to verify the design and material selection. Vehicle dynamics of the car is analysed to calculate the acting forces. Optimization of the design is performed by using Computer Aided Engineering. The re-designed Wheel Hub presented as the result of this project with a Brake Disk Adapter integrated in Hub. This design reduces the number of parts, and the unsprung mass up to 25% without any effects on suspension geometry or other parts of the car.

  • 23.
    Andersson, Erica
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Fritz, Sophia
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Möjligheter med kollaborativa robotar i slutmonteringen på Volvo GTO: Urvalsprinciper för en coaktiv implementation2017Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Kollaborativa robotar är ny teknik som erbjuder flexibilitet och precision för manuella arbetsuppgifter som tidigare har varit svåra att automatisera. Volvo Group Trucks Operations motorfabrik i Skövde är en pilotfabrik där nya tekniska lösningar testas innan de förs vidare i koncernen. Företaget ser att kollaborativa robotar kan ge fördelar som förbättringar i ergonomin för operatörerna samt förbättrad process- och produktkvalitet i slutmonteringen för 13L lastbilsmotorer. Projektets syfte är att undersöka möjligheter med kollaborativa robotar i slutmonteringen samt ge en djupare förståelse för robotarnas användningsområde. Projektet har avgränsats till Universal Robots, kitt, förarbete och slutmontering för 13L lastbilsmotorer. Målen är att ta fram utmärkande egenskaper för en coaktiv implementation, ta fram urvalsprinciper och samlokalisera möjliga arbetsmoment till en coaktiv station och om samlokalisering inte är möjligt, ge rekommendation om minimala egenskaper som bör finnas hos den kollaborativa roboten. 

    För att nå målen har en systematisk metod framställts för att säkerställa att projektet förhåller sig till problemet och målen. Kunskap har samlats in genom litteraturstudie och referensram för att ligga som grund till det praktiska arbetet. Alla arbetsmoment i område 1–4 på produktionslinjen har identifierats och analyserats för att urskilja coaktiva egenskaper som sedan har varit grunden till att ta fram urvalsprinciper. Flera av de egenskaper som har tagits fram från produktionslinjen stämmer överens med vad en Universal Robot kan utföra. Att dessa egenskaper stämmer överens visar att en kollaborativ robot är möjlig att implementera i slutmonteringen. Urvalsprinciperna har sedan använts för att samlokalisera två coaktiva stationer i produktionslinjen.

    Urvalsprinciperna kommer att kunna användas som beslutsunderlag för företaget vid en implementation av kollaborativa robotar. I takt med att tekniken kring kollaborativa robotar utvecklas behöver också egenskaperna och urvalsprinciperna uppdateras.

  • 24.
    Andersson Lassila, Andreas
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Folcke, Marcus
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Numerical and experimental analysis of adhesively bonded T-joints: Using a bi-material interface and cohesive zone modelling2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    With increasing climate change the automotive industry is facing increasing demands regarding emissions and environmental impact. To lower emissions and environmental impact the automotive industry strives to increase the efficiency of vehicles by for example reducing the weight. This can be achieved by the implementation of lightweight products made of composite materials where different materials must be joined. A key technology when producing lightweight products is adhesive joining.

    In an effort to expand the implementations of structural adhesives Volvo Buses wants to increase their knowledge about adhesive joining techniques. This thesis is done in collaboration with Volvo Buses and aims to increase the knowledge about numerical simulations of adhesively bonded joints. A numerical model of an adhesively bonded T-joint is presented where the adhesive layer is modelled using the Cohesive Zone Model. The experimental extraction of cohesive laws for adhesives is discussed and implemented as bi-linear traction-separation laws. Experiments of the T-joint for two different load cases are performed and compared to the results of the numerical simulations. The experimental results shows a similar force-displacement response as for the results of the numerical simulations. Although there were deviations in the maximum applied load and for one load case there were deviations in the behavior after the main load drop. The deviations between numerical and experimental results are believed to be due to inaccurate material properties for the adhesive, the use of insufficient bi-linear cohesive laws, the occurrence of a combination of adhesive and cohesive fractures during the experiments and dissimilar effective bonding surface areas in the numerical model and the physical specimens.

  • 25.
    Andersson, Louise
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Erlandsson, Stefan
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Utveckling av ett lyftverktyg för skivformade produkter2014Independent thesis Basic level (professional degree), 15 poäng / 22,5 hpOppgave
    Abstract [sv]

    Under höstterminen 2013 har Stefan Erlandsson och Louise Andersson, designingenjörsstudenter på Högskolan i Skövde, utfört ett produktutvecklingsprojekt i samarbete med entreprenören Lars Willebrand. Målsättningen för projektet var att utveckla ett lyftverktyg som ska komplettera Willebrands produktserie bestående av; travers, svängkran, plåtbyrå och lyftverktyg. Lyftverktyget ska vara anpassat för att användas i kombination med en plåtbyrå, vilket innebär att det kommer användas till att lyfta material från höga och låga höjder. Lyftverktyget måste därmed konstrueras i syfte att underlätta för användaren och undvika arbetsskador som kan uppstå vid dessa lyft. Lyftverktyget ska även kunna anpassas till kunder som endast avser att lyfta skivformade produkter i midjehöjd.

    Projektet inleds med en förstudie där mycket fokus läggs på ergonomi och användaren. Förstudien har gjorts genom fördjupning i relevant litteratur, kontakt med industriföretag och genom att analysera konkurrerande lyftverktyg. Resultatet från förstudien har sammanfattats till en kravspecifikation som legat till grund för konceptframtagningen. Konceptframtagningen har skett stegvis, där lyftverktygets huvudfunktioner utvecklats var för sig. De funktioner som utvecklats är justering av sugkopparnas position, manövrering och lyft vid hög/låg höjd. Alternativa lösningar har tagits fram och utvärderats för att hitta den lämpligaste lösningen på varje enskild funktion. När de bästa lösningarna hade tagits fram sattes dessa samman till ett slutgiltigt koncept.

    Det slutgiltiga konceptet har analyserats och detaljutvecklats. För att underlätta tillverkning och tillgodose kundens behov har många av lyftverktygets delar anpassats och ritats om. För att säkerställa att lyftverktyget lever upp till kravspecifikationen har hållfasthetsberäkningar och en antropometrisk analys genomförts. Projektets process och resultat sammanfattades och diskuterades. Slutligen gavs förslag på rekommendationer för fortsatt utveckling av lyftverktyget.

  • 26.
    Andersson, Martin
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    A bilevel approach to parameter tuning of optimization algorithms using evolutionary computing: Understanding optimization algorithms through optimization2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Most optimization problems found in the real world cannot be solved using analytical methods. For these types of difficult optimization problems, an alternative approach is needed. Metaheuristics are a category of optimization algorithms that do not guarantee that an optimal solution will be found, but instead search for the best solutions using some general heuristics. Metaheuristics have been shown to be effective at finding “good-enough” solutions to a wide variety of difficult problems. Most metaheuristics involve control parameters that can be used to modify how the heuristics perform its search. This is necessary because different problems may require different search strategies to be solved effectively. The control parameters allow for the optimization algorithm to be adapted to the problem at hand. It is, however, difficult to predict what the optimal control parameters are for any given problem. The problem of finding these optimal control parameter values is known as parameter tuning and is the main topic of this thesis. This thesis uses a bilevel optimization approach to solve parameter tuning problems. In this approach, the parameter tuning problem itself is formulated as an optimization problem and solved with an optimization algorithm. The parameter tuning problem formulated as a bilevel optimization problem is challenging because of nonlinear objective functions, interacting variables, multiple local optima, and noise. However, it is in precisely this kind of difficult optimization problem that evolutionary algorithms, which are a subclass of metaheuristics, have been shown to be effective. That is the motivation for using evolutionary algorithms for the upper-level optimization (i.e. tuning algorithm) of the bilevel optimization approach. Solving the parameter tuning problem using a bilevel optimization approach is also computationally expensive, since a complete optimization run has to be completed for every evaluation of a set of control parameter values. It is therefore important that the tuning algorithm be as efficient as possible, so that the parameter tuning problem can be solved to a satisfactory level with relatively few evaluations. Even so, bilevel optimization experiments can take a long time to run on a single computer. There is, however, considerable parallelization potential in the bilevel optimization approach, since many of the optimizations are independent of one another. This thesis has three primary aims: first, to present a bilevel optimization framework and software architecture for parallel parameter tuning; second, to use this framework and software architecture to evaluate and configure evolutionary algorithms as tuners and compare them with other parameter tuning methods; and, finally, to use parameter tuning experiments to gain new insights into and understanding of how optimization algorithms work and how they can used be to their maximum potential. The proposed framework and software architecture have been implemented and deployed in more than one hundred computers running many thousands of parameter tuning experiments for many millions of optimizations. This illustrates that this design and implementation approach can handle large parameter tuning experiments. Two types of evolutionary algorithms, i.e. differential evolution (DE) and a genetic algorithm (GA), have been evaluated as tuners against the parameter tuning algorithm irace. The as pects of algorithm configuration and noise handling for DE and the GA as related to the parameter tuning problem were also investigated. The results indicate that dynamic resampling strategies outperform static resampling strategies. It was also shown that the GA needs an explicit exploration and exploitation strategy in order not become stuck in local optima. The comparison with irace shows that both DE and the GA can significantly outperform it in a variety of different tuning problems.

  • 27.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Towards Optimal Algorithmic Parameters for Simulation-Based Multi-Objective Optimization2016Inngår i: 2016 IEEE Congress on Evolutionary Computation (CEC), New York: IEEE, 2016, s. 5162-5169Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of optimization to solve a simulation-based multi-objective problem produces a set of solutions that provide information about the trade-offs that have to be considered by the decision maker. An incomplete or sub-optimal set of solutions will negatively affect the quality of any subsequent decisions. The parameters that control the search behavior of an optimization algorithm can be used to minimize this risk. However, choosing good parameter settings for a given optimization algorithm and problem combination is difficult. The aim of this paper is to take a step towards optimal parameter settings for optimization of simulation-based problems. Two parameter tuning methods, Latin Hypercube Sampling and Genetic Algorithms, are used to maximize the performance of NSGA-II applied to a simulation-based problem with discrete variables. The strengths and weaknesses of both methods are analyzed. The effect of the number of decision variables and the function budget on the optimal parameter settings is also studied.

  • 28.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Tuning of Multiple Parameter Sets in Evolutionary Algorithms2016Inngår i: GECCO'16: Proceedings of the 2016 genetic and evolutionary computation conference, Association for Computing Machinery (ACM), 2016, s. 533-540Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Evolutionary optimization algorithms typically use one or more parameters that control their behavior. These parameters, which are often kept constant, can be tuned to improve the performance of the algorithm on specific problems. However, past studies have indicated that the performance can be further improved by adapting the parameters during runtime. A limitation of these studies is that they only control, at most, a few parameters, thereby missing potentially beneficial interactions between them. Instead of finding a direct control mechanism, the novel approach in this paper is to use different parameter sets in different stages of an optimization. These multiple parameter sets, which remain static within each stage, are tuned through extensive bi-level optimization experiments that approximate the optimal adaptation of the parameters. The algorithmic performance obtained with tuned multiple parameter sets is compared against that obtained with a single parameter set. For the experiments in this paper, the parameters of NSGA-II are tuned when applied to the ZDT, DTLZ and WFG test problems. The results show that using multiple parameter sets can significantly increase the performance over a single parameter set.

  • 29.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Syberfeldt, Anna
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Parameter tuned CMA-ES on the CEC'15 expensive problems2015Inngår i: Evolutionary Computation, IEEE conference proceedings, 2015, s. 1950-1957Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Evolutionary optimization algorithms have parameters that are used to adapt the search strategy to suit different optimization problems. Selecting the optimal parameter values for a given problem is difficult without a-priori knowledge. Experimental studies can provide this knowledge by finding the best parameter values for a specific set of problems. This knowledge can also be constructed into heuristics (rule-of-thumbs) that can adapt the parameters for the problem. The aim of this paper is to assess the heuristics of the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) optimization algorithm. This is accomplished by tuning CMA-ES parameters so as to maximize its performance on the CEC'15 problems, using a bilevel optimization approach that searches for the optimal parameter values. The optimized parameter values are compared against the parameter values suggested by the heuristics. The difference between specialized and generalized parameter values are also investigated.

  • 30.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Syberfeldt, Anna
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Parameter Tuning of MOEAs Using a Bilevel Optimization Approach2015Inngår i: Evolutionary Multi-Criterion Optimization: 8th International Conference, EMO 2015, Guimarães, Portugal, March 29 --April 1, 2015. Proceedings, Part I / [ed] António Gaspar-Cunha, Carlos Henggeler Antunes & Carlos Coello Coello, Springer, 2015, s. 233-247Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The performance of an Evolutionary Algorithm (EA) can be greatly influenced by its parameters. The optimal parameter settings are also not necessarily the same across different problems. Finding the optimal set of parameters is therefore a difficult and often time-consuming task. This paper presents results of parameter tuning experiments on the NSGA-II and NSGA-III algorithms using the ZDT test problems. The aim is to gain new insights on the characteristics of the optimal parameter settings and to study if the parameters impose the same effect on both NSGA-II and NSGA-III. The experiments also aim at testing if the rule of thumb that the mutation probability should be set to one divided by the number of decision variables is a good heuristic on the ZDT problems. A comparison of the performance of NSGA-II and NSGA-III on the ZDT problems is also made.

  • 31.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Parameter Tuning Evolutionary Algorithms for Runtime versus Cost Trade-off in a Cloud Computing Environment2018Inngår i: Simulation Modelling Practice and Theory, ISSN 1569-190X, Vol. 89, s. 195-205Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The runtime of an evolutionary algorithm can be reduced by increasing the number of parallel evaluations. However, increasing the number of parallel evaluations can also result in wasted computational effort since there is a greater probability of creating solutions that do not contribute to convergence towards the global optimum. A trade-off, therefore, arises between the runtime and computational effort for different levels of parallelization of an evolutionary algorithm.  When the computational effort is translated into cost, the trade-off can be restated as runtime versus cost. This trade-off is particularly relevant for cloud computing environments where the computing resources can be exactly matched to the level of parallelization of the algorithm, and the cost is proportional to the runtime and how many instances that are used. This paper empirically investigates this trade-off for two different evolutionary algorithms, NSGA-II and differential evolution (DE) when applied to multi-objective discrete-event simulation-based (DES) problem. Both generational and steadystate asynchronous versions of both algorithms are included. The approach is to perform parameter tuning on a simplified version of the DES model. A subset of the best configurations from each tuning experiment is then evaluated on a cloud computing platform. The results indicate that, for the included DES problem, the steady-state asynchronous version of each algorithm provides a better runtime versus cost trade-off than the generational versions and that DE outperforms NSGA-II.

  • 32.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bandaru, Sunith
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    A Parallel Computing Software Architecture for the Bilevel Parameter Tuning of Optimization AlgorithmsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Most optimization algorithms extract important algorithmic design decisions as control parameters. This is necessary because different problems can require different search strategies to be solved effectively. The control parameters allow for the optimization algorithm to be adapted to the problem at hand. It is however difficult to predict what the optimal control parameters are for any given problem. Finding these optimal control parameter values is referred to as the parameter tuning problem. One approach of solving the parameter tuning problem is to use a bilevel optimization where the parameter tuning problem itself is formulated as an optimization problem involving algorithmic performance as the objective(s). In this paper, we present a framework and architecture that can be used to solve large-scale parameter tuning problems using a bilevel optimization approach. The proposed framework is used to show that evolutionary algorithms are competitive as tuners against irace which is a state-of-the-art tuning method. Two evolutionary algorithms, differential evaluation (DE) and a genetic algorithm (GA) are evaluated as tuner algorithms using the proposed framework and software architecture. The importance of replicating optimizations and avoiding local optima is also investigated. The architecture is deployed and tested by running millions of optimizations using a computing cluster. The results indicate that the evolutionary algorithms can consistently find better control parameter values than irace. The GA, however, needs to be configured for an explicit exploration and exploitation strategy in order avoid local optima.

  • 33.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos H. C.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bernedixen, Jacob
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    On the Trade-off Between Runtime and Evaluation Efficiency In Evolutionary AlgorithmsInngår i: Evolutionary Computation, ISSN 1063-6560, E-ISSN 1530-9304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Evolutionary optimization algorithms typically use one or more parameters that control their behavior. These parameters, which are often kept constant, can be tuned to improve the performance of the algorithm on specific problems.  However, past studies have indicated that the performance can be further improved by adapting the parameters during runtime. A limitation of these studies is that they only control, at most, a few parameters, thereby missing potentially beneficial interactions between them. Instead of finding a direct control mechanism, the novel approach in this paper is to use different parameter sets in different stages of an optimization. These multiple parameter sets, which remain static within each stage, are tuned through extensive bi-level optimization experiments that approximate the optimal adaptation of the parameters. The algorithmic performance obtained with tuned multiple parameter sets is compared against that obtained with a single parameter set.  For the experiments in this paper, the parameters of NSGAII are tuned when applied to the ZDT, DTLZ and WFG test problems. The results show that using multiple parameter sets can significantly increase the performance over a single parameter set.

  • 34.
    Andersson, Martin
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Syberfeldt, Anna
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Ng, Amos
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Bengtsson, Victor
    Posten AB, Solna, Sweden.
    Evolutionary Simulation Optimization of Personnel Scheduling2014Inngår i: Industrial Simulation Conference, Skövde, June 11-13, 2014, Eurosis , 2014, s. 61-65Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a simulation-optimization system for personnel scheduling. The system is developed for the Swedish postal services and aims at finding personnel schedules that minimizes both total man hours and the administrative burden of the person responsible for handling schedules. For the optimization, the multi-objective evolutionary algorithm NSGA-II is implemented. The simulation-optimization system is evaluated on a real-world test case and results from the evaluation shows that the algorithm is successful in optimizing the problem.

  • 35.
    Andersson, Rasmus
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Hellgren, Martin
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    ÖKAD PRODUKTIVITET GENOM STÄLLTIDSREDUCERING: En fallstudie2014Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Kongsberg Automotive (KA) är ett företag som verkar i den hårt konkurrensutsatta fordonsbranschen. Vid en av företagets anläggningar som är placerad i Mullsjö sker montering av växelföringssystem. KA ser ett behov av att öka kapaciteten i avsnittet genom att öka produktiviteten. En stor förbättringspotential har identifierats vid omställning mellan olika produktvarianter i monteringsavsnittet. Genom ställtidsreducering förväntas kapaciteten att öka i monteringsavsnittet, vilket även bidrar till ökad flexibiliteten för att på ett konkurrenskraftigt sätt kunna möta kundernas varierade behov. För att fastställa utgångsläget vid förbättringsarbetet måste en nulägesanalys genomföras, varefter förbättringsförslag för att reducera ställtiden kan arbetas fram. Implementering av ett förbättringsförslag kan därefter genomföras. För att dokumentera nuläget samt för att påvisa förbättringar av ställtidsreduceringen upprättas en simuleringsmodell. Simuleringsmodellen påvisar ett exempel på användningsområde för verktyget produktionssimulering.

    För att genomföra ställtidsreducering användes SMED-metoden (Single-Minute Exchange of Die) som ursprungligen är framtagen för att reducera ställtiden vid pressmaskiner. Metoden syftar på att reducera ställtiden till under 10 minuter, ”single-minute”. Genom videodokumentering, deltagande observationer samt ytterligare datainsamlingsmetoder kunde nuläget fastställas. Detta skapade en bra bild över de moment som genomfördes och vilken tidsåtgång det motsvarade. För att verifiera data till nuläget genomfördes tidtagning av arbetesmoment enligt snapback metoden. Simuleringsmodellen är uppbyggd efter Banks tolvstegs-metod med de data som samlats in under projektets gång. Modellen är sedan verifierad mot det fastsällda nuläget. När förbättringsförslagen var framtagna sattes värden in i modellen som motsvarade den beräknade tidsförbättringen av förslagen. Förbättringsförslagen togs fram av projektgruppen genom en workshop tillsammans med personal på KA med fokus på fem stycken tidigare identifierade problemområden. Förbättringsförslagen värderades på workshopen genom en pick chart.

    Fem genomarbetade förbättringar som kräver liten insats men ger en stor effekt kunde presenterats för KA. För att verifiera teroetiska beräkningar genomfördes en pilotomställning med fyra av de fem förbättringarna tillfälligt implementerade. Resultatet påvisade en reducering av ställtiden från 38 minuter till 3,7 minuter vilket motsvarar en förbättring på 90.3%. Analyser visar på att förbättringsförslagen också ökar kapaciteten vid normal montering. Totalt kommer förbättringarna i detta projekt öka TAK-värdet i monteringsavsnittet med 4.2%. Trots detta kommer inte ett av det uppställda målet i projektet att uppnås eftersom tiden för omställningsaktiviteterna utgör en för liten del av den tillgängliga tiden i monteringsavsnittet. 

  • 36.
    Andersson, Rikard
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Welin, Annika
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Analys av elasticitetsmodulsvariationer i vevaxel2018Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    En studie genomförs gällande en eventuell variation av elasticitetsmodulen i Volvo Cars vevaxlar vilka levereras av underleverantör. Syftet är att möjliggöra framtida Finita element-analyser (FE-analyser) gällande den skärande bearbetning vevaxlarna utsätts för hos Volvo Cars, således önskas en undersökning göras om dessa FE-analyser kan genomföras med en konstant elasticitetsmodul. Två 4-cylindriska vevaxlar av typ 2 erhålls av Volvo Cars, vilka delas upp i fyra delar vardera och används i två experiment. Där utförande ett var ett tryckprov i dragprovmaskin på Högskolan i Skövde, samt utförande två där experiment ett efterliknas med randvillkor och last med FE-analyser och utfördes vilka utförs i programvaran Abaqus CAE. Även tre mindre delmoment utförs, ett, där vevaxeldelarna tilläts att återfjädra, två, undersökning av spännings-koncentrationer i Abaqus CAE för att undersöka en eventuell plasticering, samt tre, utförande av tryckprov i dragprovmaskin och Abaqus där vevaxeldelen utsätts för en omvänd pålagd kraft kraft läggs på från andra hållet. Erhållna resultat visar att en liten variation av E-modul finns inom de två vevaxlarna, en variationsvidd av högst 3,45 %. Denna variation kan förklaras med mätosäkerhet då utförandet med den omvända vevaxeldelen gav ett avvikande procentuellt resultat av 3,16 %, likt variationen av total nedböjning inom de två vevaxlarna. Dock bevisas en större procentuell skillnad av E-modulen i jämförelse mellan de två vevaxlarna, där skillnaden inte enbart kan förklarashärröra från med mätosäkerhet.

    Genomförda analyser visar att FE-metoden är en tillämpbar metod för att beräkna 4-cylindriga vevaxlars deformation, do E-modul , dock kan det finnas behov för Volvo Cars att utföra ytterligare undersökningar berörande en varierande E-modul mellan olika leverantörer/batcher av råmaterial för vevaxlar.

  • 37.
    Andersson, Rinat
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Johansson, Martin
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Underlag för beslut av investering i ny utrustning2016Independent thesis Basic level (university diploma), 15 poäng / 22,5 hpOppgave
  • 38.
    Andersson, Tobias
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Stigh, Ulf
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    The stress-elongation relation for an adhesive layer loaded in peel using equilibrium of energetic forces2004Inngår i: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 41, nr 2, s. 413-434Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An experimental method to determine the stress–elongation relation for a thin adhesive layer loaded in peel is presented. The method is based on equilibrium of the energetic forces acting on a DCB-specimen. These energetic forces are identified to be associated with the geometrical positions of the acting loads and the start of the adhesive layer. The first energetic force is shown to be given by the product of the force and the rotation of the loading point. The second energetic force is shown to be given by the area under the stress–elongation curve for the adhesive layer. Using equilibrium of these energetic forces, the shape of the stress–elongation curve is determined. A test set-up is developed to facilitate the experiments. Special consideration is given to the accuracy of the measurement of the elongation of the adhesive. Results from two sets of experiments with slightly varying geometry are presented. The main result is that the stress–elongation relation can be described by a curve divided into three parts; initially the stress increases proportionally to the elongation. This corresponds to a linear elastic behaviour of the layer. The next part is given by a constant limiting stress. The curve ends with a parabolically softening part. After this point, a crack has been initiated in the adhesive. The experimental results are first compared to an asymptotic analysis using linear elastic fracture mechanics. This shows that the new method to evaluate the fracture energy gives consistent results. The experiments are also simulated using the measured stress–elongation law. Good agreement with the experiments is achieved which further validates the method. The fracture energy and the maximum peel stress are found to agree well within each set of experiments. Some variation is found between the two sets. This is accredited to differences in fracture initiation

  • 39.
    Andersson, Viktor
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Larsson, Andreas
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Project ABSS: Adhesive bonding of stainless steels2017Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report aims to increase the scientific knowledge about long-term prospects for the adhesive and adhesive joints for bonding of stainless steels. The effects of water, temperature and chemicals on the adhesive and adhesive joints are investigated. Stainless steel plates are pretreated with a primer and isopropanol, there after joined together with single lap modeling. The strength of the joint is tested with a tensile test and additionally a watertightness test is performed to determine if the joints are watertight.

    For this project three versions of stainless steels is used and two different technologies of two- part adhesives, silicone and silane-modified polymer and one technology of tape, a double coated acrylic foam tape are tested.

    The result shows that all the adhesives fails cohesively and that tape fails partly adhesively. Result shows that all tests are affected by water, temperature and chemicals on different levels but tape is affected the most with a minimum of 40% loss in shear strength. Watertightness test shows that aged tape joints are not watertight. The polymer shows no signs of decreasing in shear strength and is watertight, but does become more viscous by aging.

    The report shows that a possible combination of adhesive and pretreatment that can withstand the effects of water, temperature and chemicals is found. The polymer presents a possibility to bond stainless steel with a simple pretreatment. Tape didn’t pass the test in a suitable way but presents opportunities if a sufficient pretreatment can be found. 

  • 40.
    Andreasson, Rebecca
    et al.
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Lindblom, Jessica
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Thorvald, Peter
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Distributed Cognition in Manufacturing: Collaborative Assembly Work2016Inngår i: Advances in Manufacturing Technology XXX / [ed] Yee Mey Goh, Keith Case, IOS Press, 2016, s. 243-248Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cognitive science is becoming increasingly central within humanfactors and ergonomics (HF&E) and there has long been a call for a more systemicperspective in the area with a somewhat broader unit of analysis. This paperpresents a case study applying the theoretical framework of distributed cognition(DCog), which shows how DCog would offer a more complete understanding ofmanufacturing within its greater context, including the social, cultural, andmaterial surroundings. This paper aims to characterize and analyse dock assemblyof forest machines as a complex socio-technical system from a DCog perspective;focusing on the creation of enacted landscapes in this particular setting. The paperalso exemplifies benefits of using the DCog framework in the manufacturingdomain as a way of grasping the assembly workers’ tacit competence and skills.

  • 41.
    Andreasson, Rebecca
    et al.
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Lindblom, Jessica
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Thorvald, Peter
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Interruptions in the wild: portraying the handling of interruptions in manufacturing from a distributed cognition lens2017Inngår i: Cognition, Technology & Work, ISSN 1435-5558, E-ISSN 1435-5566, Vol. 19, nr 1, s. 85-108Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a study examining interruptionsin the wild by portraying the handling of interruptionsin manufacturing from a distributed cognitionlens. By studying how interruptions occur and are handledin the daily activities of a work team at a large foundry forcasting heavy diesel engines, we highlight situations whenthe propagation, transformation, and representation ofinformation are not supported by prescribed work processesand propose recommendations for how this can beamended. The study was conducted by several visits to theaforementioned factory with cognitive ethnography as thebasis for the data collection. The focus was on identifyinginterruptions and analysing these through a distributedcognition framework as an initial step towards studyinginterruptions in a manufacturing environment. The keyfindings include the identification of three, previouslyundefined, types of interruptions and the conclusion thatinterruptions do indeed affect the distributed workload ofthe socio-technical system and thus the overall productionperformance at the casting line.

  • 42.
    Andreasson, Rebecca
    et al.
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi. Department of Information Technology, Visual Information and Interaction, Uppsala University, Uppsala, Sweden.
    Lindblom, Jessica
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Thorvald, Peter
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Tool use and collaborative work of dock assembly in practice2017Inngår i: Production & Manufacturing Research, ISSN 2169-3277, Vol. 5, nr 1, s. 164-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to deepen the understanding of the intrinsic interactions andinterplay between humans, tools, and environment from a systemsperspective, research in the wild (RITW) approaches have gainedtraction during recent decades as they provide a higher ecologicalvalidity of findings. This paper presents a RITW study, investigatinghow assembly, in this case dock assembly of forwarders, was donein practice. As our theoretical foundation, we used the framework ofdistributed cognition, which is one of the main pillars of RITW. Thefindings are presented in narrative form, describing and highlightingthat the workers achieve an efficient production outcome by beingintegral parts of the whole production process and doing so throughcoordination of activities benefitting the shared goal of the distributedsocio-technical system.

  • 43.
    Andreasson, Rebecca
    et al.
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Lindblom, Jessica
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Thorvald, Peter
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Towards an increased degree of usability work in organizations2015Inngår i: Procedia Manufacturing, ISSN 2351-9789, Vol. 3, s. 5739-5746Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is widely recognized that there is a substantial gap between usability research and practice where UCD approaches are rarelyapplied in practice due to arguments regarding the intricate nature of its methods and techniques. This paper presents an actionresearch study designed to investigate and analyze the potentials for an increased degree of UCD activities in the earlydevelopment phases of advanced information systems technology. The results demonstrate that there is a large interest inusability but that organizational priority and competence is often lacking. Instead one relies heavily on questionable conceptssuch as „trained professionals‟ to excuse the low effort towards usability. Based on the results, six recommendations forimproved usability work in R&D organizations are presented, focusing on the importance of prioritization of, and education inusability work.

  • 44.
    Aragón Martín, Laura
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Alternative materials for the horseshoe2014Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    This thesis is a research-focused work on a study of alternative materials for horseshoes. Within this thesis the objectives and functions of a compliant horseshoe are identified, based on a literature study of the work of previous researches, and they are linked to the properties of material. After identifying these objectives, a number of methods are implemented with the aim of detecting the most suitable materials for horseshoes taking into account the properties linked with the objectives. In order to determine whether the selected material is suitable or not, a comparison with a traditional forged steel horseshoe is carried out. Whenever an appropriate material is found, a most exhaustive study is performed and finally, a decision is elected based on the further investigation. The last chapter of this thesis is comprised of a document destined for future researches where suggestions about how to get more reliable results in the field are explained.

  • 45.
    Arambarri Iglesias, Oihane
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Arauzo Sanchez, Ane
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Design of a medical mask for users with Multiple Chemical Sensitivity2016Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    Within this degree project a conceptual design of a mask has been developed for people with Multiple Chemical Sensitivity due to the lack of this kind of product in the market. The users currently use different masks that are designed to be used in other activities.  A preliminary study has been performed where market, ergonomics, materials and use situations have been analysed to gather knowledge to define the specifications of the product. Even if  the aesthetics of the first version of the product’s design was related to a health care design style, after obtaining results, it was observed that the wishes of the users weren’t being fulfilled. After updating the specifications and the generation phase three possible concepts have been presented. The evaluation has been done within the design group and the target users from the Basque association “Bizi-Bide”. The final conceptual design has been developed regarding different aspects such as ergonomics, materials, components and graphic design. The project has resulted in a concept of an innovative mask, which has a mouldable part for the nose and cheeks, a Velcro fastener to adapt it to different head measurements and exchangeable filters. 

  • 46.
    Arehorn, Magnus
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Ekholm, Niklas
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Utveckling av lattbeslag för segelbåtar mellan 45 och 60 fot2016Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Projektet har utförts av designingenjörsstudenterna Magnus Arehorn och Niklas Ekholm under vårterminen 2016 i kursen Examensarbete inom integrerad produktutveckling på Högskolan i Skövde. Projektet har genomförts för Seldén Mast AB i Långedrag, Göteborg, som utvecklar däcks- och riggsutrustning för segelbåtar.Seldén har lattbeslag för segelbåtar upp till 45 fot, men vill utöka sitt sortiment till marknad för större segelbåtar. De befintliga lattbeslagen skulle då inte vara tillräckligt robusta varför ett nytt beslag krävs med starkare konstruktion. Målet var att utveckla ett lattbeslag för segelbåtar mellan 45 och 60 fot. Syftet med lattbeslaget är att spänna upp lattor i storseglet och utfå bättre vindupptagning.Utvecklingsområden undersöktes genom att delfunktioner för beslaget identifierades. En förstudie inleddes för att forska i utvecklingsmöjligheter inom områdena genom att se till befintliga lösningar via konkurrensanalys och behov i intervjuer med segelmakare och seglare. Beslaget förväntades vara billigt, robust, funktionellt samt unikt. Slutsatsen drogs att unika lösningar behövde finnas till en låg tillverkningskostnad.En idégenerering inleddes för att finna koncept med nytänkande och beprövade lösningar till låga kostnader. Två potentiella koncept togs fram som efter detaljutveckling viktades för att stå med ett slutligt resultat. Resultatet bedömdes vara ovanligt på marknaden och uppskattades ha en relativt låg tillverkningskostnad.

  • 47.
    Areitioaurtena Oiartzun, Maialen
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Mixed material bonding: Effects of the properties of the adhesive on the thermal shape distortion2016Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    Adhesive bond-line read-through is the terminology used in the automotive industry that describes a visible distortion of an adherent over the adhesive bond-line. Usually, this is a result of the difference in the coefficients of thermal expansion of the substrates and the adhesive. First of all, previous work is presented, as well as some information about the terms that are used throughout the project. A linear thermal simulation is carried out in order to analyse the bond-line read-through curvature defects produced by the adhesive properties in a typical bonding from the automotive industry. The analysed models belong to a carbon fibre and epoxy composite material plate bonded with a metal plate that can be made of steel, aluminium and magnesium. The use of carbon fibre composites is one of the main focuses in the automotive industry due to the decrease of environmental and therefore economic impact. The adhesives used for the analysis are liquid or paste adhesive and adhesive tapes from the 3M™ VHB™ series. Several equations are obtained from the results, which can be used to calculate the curvature produced by a specific adhesive for these combinations. The use of these equations is limited to certain material properties and thicknesses that are presented through the work. The outcome of this project provides an opportunity to make the adhesive selection easier, based on the maximum required substrate curvature.

  • 48.
    Arteaga Viafara, Edinson Elan
    et al.
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Linders, Linders
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap.
    Utveckling av en postlåda för montage på säkerhetsdörrar2016Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Denna uppsats går igenom skapandet av ett konstruktionsförslag av en postlåda för montage på säkerhetsdörrar. Projektet genomfördes i samarbete med ett företag som tillverkar säkerhetsdörrar i stål. Syftet med arbetet har varit att på uppdrag av företaget utarbeta ett designförslag för en postlåda med ett flertal nya funktioner samt med en innovativ estetisk formgivning. Designen får inte kompromissa med gällande säkerhetskrav samt bör inkludera en bredare målgrupp.

    Enligt Frenchs modell har en metod använts där användarstudier, tester och fokusgrupper gett viktig information. Designprinciperna inclusive design, pleasure design och gamification har varit ledstjärnor i designprocessen.

    En funktionsanalys gjordes på en vanlig postlåda som visade vilka funktioner som kan förbättras. Denna analys utgjorde grunden för den efterföljande konceptgenereringsfasen där olika designalternativ utforskades.

    Konceptgenereringen utmynnade i postlådan Droppen, där redan existerande funktioner har vidareutvecklats. Droppen-konceptet utmanar genom att exempelvis introducera LED-lampor som kommunicerar med användaren samt har ett tidningsställ, som är starkt nog att kunna bära tunga matkassar. Den har också en mjuk droppform som tilltalar många och som gör det lätt att ta upp posten. Postlådan är gjord i zinklegerat stål, vilket gör den tung men hållbar. Möjligheten till individuell anpassning av produkten ökar kundvärdet samt minskar indirekt dess miljöpåverkan

  • 49.
    Aryasetiawan, F.
    et al.
    Department of Physics, Division of Mathematical Physics, Lund University, Lund, Sweden.
    Karlsson, Krister
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Miyake, T.
    CD-FMat, AIST, Tsukuba, Japan / ESICMM, National Institute for Materials Science, Tsukuba, Japan.
    Green's function theory of orbital magnetic moment of interacting electrons in solids2016Inngår i: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 93, nr 16, artikkel-id 161104(R)Artikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Aryasetiawan, Ferdi
    et al.
    Department of Physics, Division of Mathematical Physics, Lund University, Lund, Sweden.
    Karlsson, Krister
    Högskolan i Skövde, Institutionen för ingenjörsvetenskap. Högskolan i Skövde, Forskningscentrum för Virtuella system.
    Modern theory of orbital magnetic moment in solids2017Inngår i: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, s. 1-22Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The magnetic moment in a solid is usually associated with the electron spins but there is an additional contribution due to the orbital motion of the electrons. For a finite system such as an atom or molecule the orbital moment can be readily calculated. However, for a periodic system the formula used for finite systems becomes ill-defined due to the presence of the position operator. In the last decade a modern theory of orbital magnetization that allows for a rigorous calculation of the magnetic moment of periodic crystals has been developed. This article provides a survey of the theoretical development of this new topic as well as recent, albeit a few, applications of the new formula to real materials. Although the original theory was worked out for non-interacting systems, there has been recent progress in the theory of orbital magnetic moment of interacting electrons in solids. To include the effects of electron-electron interactions two approaches have been proposed, one based on current spin density functional theory and another on the many-body Green's function method. The two approaches are very different but both methods provide convenient yet rigorous means of including the effects of exchange and correlations beyond the commonly used local density approximation of density functional theory.

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