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  • 551.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ayani, Mikel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    A holistic solution for integrating a simulated twin of an automation system during the system’s entire life-cycle2018In: Advances in Manufacturing Technology XXXII: Proceedings of the 16th International Conference on Manufacturing Research, incorporating the 33rd National Conference on Manufacturing Research, September 11–13, 2018, University of Skövde, Sweden / [ed] Peter Thorvald, Keith Case, Amsterdam: IOS Press, 2018, p. 405-410Conference paper (Refereed)
    Abstract [en]

    This paper describes a project that attempts to develop a holistic solution for integrating a simulated twin of an automation system during the system’s entire life-cycle. With such holistic solution, virtual commission could be undertaken in all steps of the life-cycle which facilitates companies in realizing flexible and intelligent automation systems. Based on the simulated twin, the companies could easily and cost-efficiently evaluate modifications, make improvements, and train operators when changes in the production setup occurs due mass-customization or new products being introduced. This aids the companies in staying competitive on a global and rapidly changing market and meet the challenges coming with the forth industrial revolution, such as mass-customization and short product life-cycles.

  • 552.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ayani, Mikel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Wang, Lihui
    Royal Institute of Technology.
    Lindgren-Brewster, Rodney
    Volvo Cars Engine, Skövde, Sweden.
    Localizing Operators in the Smart Factory: A Review of Existing Techniques and systems2016In: Proceedings of 2016 International Symposium on Flexible Automation, IEEE Computer Society, 2016, p. 186-192Conference paper (Refereed)
    Abstract [en]

    The aim of this paper to give a comprehensive overview of existing techniques and state-of-the-art systems for indoor localization that could be adopted in smart factories of the future. We present different techniques for calculating the position of a moving object using signal transmission and signal measurement,and compare their advantages and disadvantages. The paper also includes a discussion of various localization systems available in the market and compares their most important features. It ends with a discussion of important issues to consider in future work in order to fully implement indoor, real-time localization of operators in the smart factory.

  • 553.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Danielsson, Oscar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Gustavsson, Patrik
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Augmented Reality Smart Glasses in the Smart Factory: Product Evaluation Guidelines and Review of Available Products2017In: IEEE Access, E-ISSN 2169-3536, Vol. 5, p. 9118-9130, article id 7927376Article in journal (Refereed)
    Abstract [en]

    Augmented reality smart glasses (ARSG) are increasingly popular and have been identified as a vital technology supporting shop-floor operators in the smart factories of the future. By improving our knowledge of how to efficiently evaluate and select ARSG for the shop-floor context, this paper aims to facilitate and accelerate the adoption of ARSG by the manufacturing industry. The market for ARSG has exploded in recent years, and the large variety of products to select from makes it not only difficult but also time consuming to identify the best alternative. To address this problem, this paper presents an efficient step-by-step process for evaluating ARSG, including concrete guidelines as to what parameters to consider and their recommended minimum values. Using the suggested evaluation process, manufacturing companies can quickly make optimal decisions about what products to implement on their shop floors. The paper demonstrates the evaluation process in practice, presenting a comprehensive review of currently available products along with a recommended best buy. The paper also identifies and discusses topics meriting research attention to ensure that ARSG are successfully implemented on the industrial shop floor.

  • 554.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Danielsson, Oscar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ekblom, Tom
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Augmented Reality at the Industrial Shop-Floor2014In: Augmented and Virtual Reality / [ed] Lucio Tommaso De Paolis, Antonio Mongelli, Springer Berlin/Heidelberg, 2014, p. 201-209Conference paper (Refereed)
    Abstract [en]

    This paper describes a study of the potential of using augmented real-ityat the industrial shop-floor with the aim ofimprovingthe capability of the shop-floor operators. In the study, aprototype systemfor augmented reality is developed based on the Oculus Rift platform. The systemisevaluated through an experimentin which a physical three-dimensionalpuzzleis to be assembled.

  • 555.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Danielsson, Oscar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Wang, Lihui
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Royal Institute of Technology, Stockholm, Sweden.
    Dynamic operator instructions based on augmented reality and rule-based expert systems2016In: 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, p. 346-351Conference paper (Refereed)
    Abstract [en]

    Augmented reality is currently a hot research topic within manufacturing and a great potential of the technique is seen. In this study, we aim to increase the knowledge of the adaptation and usability of augmented reality for the training of operators. We propose an approach of using dynamic information content that is automatically adjusted to the individual operator and his/her learning progress for increased efficiency and shorter learning times. The approach make use of the concept of expert systems from the field of artificial intelligence for determine the information content on-line. We develop a framework called "Augmented Reality Expert System" (ARES) that combines AR and expert systems. A proof-of-concept evaluation of the framework is presented in the paper and possible future extensions are discussed.

  • 556.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Danielsson, Oscar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Wang, Lihui
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Royal Institute of Technology, Stockholm, Sweden.
    Visual Assembling Guidance Using Augmented Reality2015In: Procedia Manufacturing, ISSN 2351-9789, Vol. 1, p. 98-109Article in journal (Refereed)
    Abstract [en]

    This paper describes a study of using the concept of augmented reality for supporting assembly line workers in carrying out their task optimally. By overlaying virtual information on real world objects – and thereby enhance the human’s perception of reality – augmented reality makes it possible to improve the visual guidance to the workers.  In the study, a prototype system is developed based on the Oculus Rift platform and evaluated using a simulated assembling task. The main aim is to investigate user acceptance and how this can possible be improved. 

  • 557.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ekblom, Tom
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    A comparative evaluation of the GPU vs. the CPU for parallelization of evolutionary algorithms through multiple independent runs2017In: International Journal of Computer Science & Information Technology (IJCSIT), ISSN 0975-4660, E-ISSN 0975-3826, Vol. 9, no 3, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Multiple independent runs of an evolutionary algorithm in parallel are often used to increase the efficiency of parameter tuning or to speed up optimizations involving inexpensive fitness functions. A GPU platform is commonly adopted in the research community to implement parallelization, and this platform has been shown to be superior to the traditional CPU platform in many previous studies. However, it is not clear how efficient the GPU is in comparison with the CPU for the parallelizing multiple independent runs, as the vast majority of the previous studies focus on parallelization approaches in which the parallel runs are dependent on each other (such as master-slave, coarse-grained or fine-grained approaches). This study therefore aims to investigate the performance of the GPU in comparison with the CPU in the context of multiple independent runs in order to provide insights into which platform is most efficient. This is done through a number of experiments that evaluate the efficiency of the GPU versus the CPU in various scenarios. An analysis of the results shows that the GPU is powerful, but that there are scenarios where the CPU outperforms the GPU. This means that a GPU is not the universally best option for parallelizing multiple independent runs and that the choice of computation platform therefore should be an informed decision. To facilitate this decision and improve the efficiency of optimizations involving multiple independent runs, the paper provides a number of recommendations for when and how to use the GPU.

  • 558.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Grimm, Henrik
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Design of Experiments for Training Metamodels in Simulation-Based Optimisation of Manufacturing Systems2008In: Proceedings of The 18th International Conference on Flexible Automation and Intelligent Manufacturing (FAIM'08), Skövde: University of Skövde , 2008Conference paper (Refereed)
  • 559.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Grimm, Henrik
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Andersson, Martin
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Karlsson, Ingemar
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Simulation-Based Optimization of a Complex Mail Transportation Network2008In: Proceedings of the 2008 Winter Simulation Conference / [ed] S. J. Mason, R. R. Hill, L. Mönch, O. Rose, T. Jefferson, J. W. Fowler, New York: IEEE conference proceedings, 2008, p. 2625-2631Conference paper (Refereed)
    Abstract [en]

    The Swedish Postal Services receives and distributes over 22 million pieces of mail every day. Mail transportation takes place overnight by airplanes, trains, trucks, and cars in a transportation network comprising a huge number of possible routes. For testing and analysis of different transport solutions, a discrete-event simulation model of the transportation network has been developed. This paper describes the optimization of transport solutions using evolutionary algorithms coupled with the simulation model. The vast transportation network in combination with a large number of possible transportation configurations and conflicting optimization criteria make the optimization problem very challenging. A large number of simulation evaluations are needed before an acceptable solution is found, making the computational cost of the problem severe. To address this problem, a computationally cheap surrogate model is used to offload the optimization process.

  • 560.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Grimm, Henrik
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Moore, Philip
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Multi-Objective Evolutionary Simulation-Optimization of a Real-World Manufacturing Problem2008In: Proceedings of The 18th International Conference on Flexible Automation and Intelligent Manufacturing (FAIM'08), Skövde: University of Skövde , 2008Conference paper (Refereed)
  • 561.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Gustavsson, Patrik
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Increased Robustness of Product Sequencing using Multi-Objective Optimization2014In: Proceeding of 47th CIRP Conference on Manufacturing Systems, Elsevier, 2014, Vol. 17, p. 434-439Conference paper (Refereed)
    Abstract [en]

    Almost all manufacturing processes are subject to uncontrollable variations, caused, for example, by human operators or worn-out machines. When optimizing real-world product sequencing problems, it is of importance to find solutions that are robust, that is, whose performance remains relatively unchanged when exposed to uncertain conditions. In this paper, an extension of the traditional method of handling variations through replications is suggested that aims at finding solutions with an increased degree of robustness. The basic idea is to use standard deviation as an additional optimization objective and transform the single-objective problem into a multi-objective problem. Using standard deviation as an additional objective aims to focus the optimization on solutions that exhibit both high performance and high robustness (that is, having low standard deviation). In order to optimize the two objectives simultaneously, a multi-objective evolutionary algorithm is utilized. The proposed method for improved robustness is evaluated using a real-world test case found at the company GKN Aerospace in Sweden. GKN Aerospace manufactures a variety of different components for aircraft engines and aero derivative gas turbines. The company has recently installed a new workshop, and the focus of the study is on the x-ray stations in this workshop. For performing optimizations the company has created a simulation model that realistically mimics the workshop. As an optimization technique, a multi-objective evolutionary algorithm called NSGA-2 is being used. The algorithm considers the mean value and standard deviation from replications of the stochastic simulation as objectives, optimizing both of them simultaneously. Results from the study show that the optimization is able to successfully find robust solutions using the proposed method. However, the general increase in algorithm performance expected with the proposed method is absent, and possible reasons for this are discussed in the paper.

  • 562.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Gustavsson, Patrik
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Robust product sequencing through evolutionary multi-objective optimisation2015In: International Journal of Manufacturing Research, ISSN 1750-0591, Vol. 10, no 4, p. 371-383Article in journal (Refereed)
    Abstract [en]

    This paper describes a study on efficient optimisation of real-world product sequencing problems with the aim of finding robust solutions. Robust solutions are insensitive to unforeseen disturbances in a manufacturing process, which is a critical characteristic for a successful realisation of optimisation results in manufacturing. In the paper, the traditional method of achieving robust solutions is extended by using standard deviation as an additional optimisation objective. This transforms the original single-objective optimisation problem into a multi-objective problem. Using standard deviation as an additional objective focuses the optimisation on solutions that have both high performance and a high degree of robustness (that is, a low standard deviation). In order to optimise the two objectives simultaneously, a multi-objective evolutionary algorithm based on the Pareto approach is used. The multi-objective method for increased robustness is evaluated using both a benchmark problem and a real-world test case. The real-world test case is from GKN Aerospace in Sweden which manufactures components for aircraft engines and aero-derivative gas turbines. Results from the evaluation show that the method successfully increases the robustness while maintaining high performance of the optimisation.

  • 563.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Gustavsson, Patrik
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Svantesson, Joakim
    GKN Aerospace.
    Almgren, Torgny
    GKN Aerospace.
    A Case Study of Evolutionary Simulation Based Optimization in Aircraft Engine Manufacturing2014In: Industrial Simulation Conference, Skövde, June 11-13, 2014, 2014, p. 91-96Conference paper (Refereed)
  • 564.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Danielsson, Oscar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Wang, Lihui
    Royal Institute of Technology, Stockholm, Sweden.
    Lindgren Brewster, Rodney
    Volvo Cars Engine, Skövde, Sweden.
    Support Systems on the Industrial Shop-floors of the Future: Operators' Perspective on Augmented Reality2016In: 6th CIRP Conference on Assembly Technologies and Systems (CATS) / [ed] Rikard Söderberg, Elsevier, 2016, Vol. 44, p. 108-113Conference paper (Refereed)
    Abstract [en]

    With augmented reality, virtual information can be overlaid on the real world in order to enhance a human’s perception of reality. In this study, we aim to deepen the knowledge of augmented reality in the shop-floor context and analyze its role within smart factories of the future. The study evaluates a number of approaches for realizing augmented reality and discusses advantages and disadvantages of different solutions from a shop-floor operator’s perspective. The evaluation is done in collaboration with industrial companies, including Volvo Cars and Volvo GTO amongst others. The study also identifies important future research directions for utilizing the full potential of the technology and successfully implement it on industrial shop-floors.

  • 565.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Karlsson, Ingemar
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    An Industrial Case Study of Web-based Simulation-Optimization2011In: Proceedings of the 9th Industrial Simulation Conference, Eurosis , 2011, p. 115-120Conference paper (Refereed)
    Abstract [en]

    This paper presents a web-based simulation-optimization system for improving production schedules in an advanced manufacturing cell at Volvo Aero Corporation in Sweden. The optimization aims at prioritizing components being processed in the cell in a way that minimizes both tardiness and lead times. Results from evaluating the implemented system shows a great improvement potential, but also indicates that further development is necessary before the system can be taken into operation.

  • 566.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Karlsson, Ingemar
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Svantesson, Joakim
    Volvo Aero Corporation, SE- 461 81 Trollhättan, Sweden.
    Almgren, Torgny
    Volvo Aero Corporation, SE- 461 81 Trollhättan, Sweden.
    A web-based platform for the simulation-optimization of industrial problems2013In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 64, no 4, p. 987-998Article in journal (Refereed)
    Abstract [en]

    This study presents a platform for industrial, real-world simulation-optimization based on web techniques. The design of the platform is intended to be generic and thereby make it possible to apply the platform in various problem domains. In the implementation of the platform, modern web techniques, such as Ajax, JavaScript, GWT, and ProtoBuf, are used. The platform is tested and evaluated on a real industrial problem of production optimization at Volvo Aero Corporation, a company that develops and manufactures high-technology components for aircraft and gas turbine engines. The results of the evaluation show that while the platform has several benefits, implementing a web-based system is not completely straightforward. At the end of the paper, possible pitfalls are discussed and some recommendations for future implementations are outlined. (C) 2013 Elsevier Ltd. All rights reserved.

  • 567.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Lidberg, Simon
    Volvo Cars Engine, Skövde, Sweden.
    Real-world simulation-based manufacturing optimization using cuckoo search2012In: Proceedings of the 2012 Winter Simulaiton Conference, IEEE, 2012, article id 6465158Conference paper (Refereed)
    Abstract [en]

    This paper describes a case study of real-world simulation-based optimization of an engine manufacturing line. The optimization aims to maximize utilization of machines and at the same time minimize tied-up capital by manipulating 56 unique decision variables. A recently proposed metaheuristic algorithm that has achieved successful results in various problem domains called Cuckoo Search is used to perform the simulation-based optimization. To handle multiple objectives, an extension of the original Cuckoo Search algorithm based on the concept of Pareto optimality is proposed and used in the study. The performance of the algorithm is analyzed in comparison with the benchmark algorithm NSGA-II. Results show that the combinatorial nature of the optimization problem causes difficulties for the Cuckoo Search algorithm, and a further analysis indicates that the algorith might be best suited for contiunuous optimization problems.

  • 568.
    Syberfeldt, Anna
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Ng, Amos
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    John, Robert I.
    De Montfort University.
    Moore, Philip
    De Montfort University.
    Evolutionary optimisation of noisy multi-objective problems using confidence-based dynamic resampling2010In: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 204, no 3, p. 533-544Article in journal (Refereed)
    Abstract [en]

    Many real-world optimisation problems approached by evolutionary algorithms are subject to noise. When noise is present, the evolutionary selection process may become unstable and the convergence of the optimisation adversely affected. In this paper, we present a new technique that efficiently deals with noise in multi-objective optimisation. This technique aims at preventing the propagation of inferior solutions in the evolutionary selection due to noisy objective values. This is done by using an iterative resampling procedure that reduces the noise until the likelihood of selecting the correct solution reaches a given confidence level. To achieve an efficient utilisation of resources, the number of samples used per solution varies based on the amount of noise in the present area of the search space. The proposed algorithm is evaluated on the ZDT benchmark problems and two complex real-world problems of manufacturing optimisation. The first real-world problem concerns the optimisation of engine component manufacturing in aviation industry, while the second real-world problem concerns the optimisation of a camshaft machining line in automotive industry. The results from the optimisations indicate that the proposed technique is successful in reducing noise, and it competes successfully with other noise handling techniques.

  • 569.
    Syberfeldt, Anna
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Ng, Amos
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    John, Robert I.
    Centre for Computational Intelligence, De Montfort University, Leicester, United Kingdom.
    Moore, Philip
    Computing Sciences and Engineering, De Montfort University, Leicester, United Kingdom.
    Multi-objective evolutionary simulation-optimisation of a real-world manufacturing problem2009In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 25, no 6, p. 926-931Article in journal (Refereed)
    Abstract [en]

    Many real-world manufacturing problems are too complex to be modelled analytically. For these problems, simulation can be a powerful tool for system analysis and optimisation. While traditional optimisation methods have been unable to cope with the complexities of many problems approached by simulation, evolutionary algorithms have proven to be highly useful. This paper describes how simulation and evolutionary algorithms have been combined to improve a manufacturing cell at Volvo Aero in Sweden. This cell produces high-technology engine components for civilian and military airplanes, and also for space rockets. Results from the study show that by using simulation and evolutionary algorithms, it is possible to increase the overall utilisation of the cell and at the same time decrease the number of overdue components.

  • 570.
    Syberfeldt, Anna
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Persson, Lars
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Using Heuristic Search for Initiating the Genetic Population in Simulation-Based Optimization of Vehicle Routing Problems2009In: Proceedings of Industrial Simulation Conference, EUROSIS-ETI , 2009Conference paper (Refereed)
    Abstract [en]

    Genetic algorithms are nowadays commonly used in simulation-based optimization of vehicle routing problems. These algorithms work with a population of solutions that are iteratively improved in an evolutionary process. Usually, the initial population is created randomly. In general, this is not very efficient since it takes unnecessarily long time before sufficiently good solutions have evolved. For a better performance of genetic algorithms, this work describes the use of heuristic search for creating the initial population. A new heuristic search procedure is described in the paper and evaluated using a real-world problem of garbage collection. The results from the evaluation show that the new procedure is able to improve a genetic algorithm.

  • 571.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Rogström, Joel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    A two-step multi-objectivization method for improved evolutionary optimization of industrial problems2018In: Applied Soft Computing, ISSN 1568-4946, E-ISSN 1872-9681, Vol. 64, p. 331-340Article in journal (Refereed)
    Abstract [en]

    Multi-objectivization means that helper objectives are added to an optimization problem with the purpose of altering the search space in a way that improves the progress of the optimization algorithm. In this paper, a new method for multi-objectivization is proposed that is based on a two-step process. In the first step, a helper objective that conflicts with the main objective is added, and in the second step a helper objective that is in harmony with, but subservient to, the main objective is added. In contrast to existing methods for multi-objectivization, the proposed method aims at obtaining improved results in real-world optimizations by focusing on three aspects: (a) adding as little extra complexity to the problem as possible, (b) achieving an optimal balance between exploration and exploitation in order to promote an efficient search, and (c) ensuring that the main objective, which is of main interest to the user, is always prioritized. Results from evaluating the proposed method on a complex real-world scheduling problem and a theoretical benchmark problem show that the method outperforms both a traditional single-objective approach and the prevailing method for multi-objectivization. Besides describing the proposed method, the paper also outlines interesting aspects of multi-objectivization to investigate in the future.

  • 572.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Rogström, Joel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Geertsen, André
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Simulation-based Optimization of a Real-world Travelling Salesman Problem Using an Evolutionary Algorithm with a Repair Function2015In: International Journal of Artificial Intelligence and Expert Systems, ISSN 2180-124X, Vol. 6, no 3, p. 27-39Article in journal (Refereed)
    Abstract [en]

    This paper presents a real-world case study of optimizing waste collection in Sweden. The problem, involving approximately 17,000 garbage bins served by three bin lorries, is approached as a travelling salesman problem and solved using simulation-based optimization and an evolutionary algorithm. To improve the performance of the evolutionary algorithm, it is enhanced with a repair function that adjusts its genome values so that shorter routes are found more quickly. The algorithm is tested using two crossover operators, i.e., the order crossover and heuristic crossover, combined with different mutation rates. The results indicate that the order crossover is superior to the heuristics crossover, but that the driving force of the search process is the mutation operator combined with the repair function.

  • 573.
    Syberfeldt, Anna
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Syberfeldt, Sanny
    University of Skövde, The Informatics Research Centre. University of Skövde, School of Humanities and Informatics.
    A serious game for understanding artificial intelligence in production optimization2010In: Proceedings of the 2010 IEEE Conference on Computational Intelligence and Games, CIG2010, IEEE , 2010, p. 443-449Conference paper (Refereed)
    Abstract [en]

    This paper describes a serious game that can be used to teach and demonstrate production optimization using artificial intelligence techniques. The game takes place in a physical Lego factory and is designed to be an enjoyable learning experience.

  • 574.
    Szekely, Bulcsu
    et al.
    Lappeenranta University of Technology.
    Hilletofth, Per
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Bakhsheshi, Amir Fazel
    Lappeenranta University of Technology.
    Role of Software Applications in Logistics Decision Making: Case of Warehouse Management Systems2009In: Networked Logistics and Production at South-East Finland, St Petersburg and Leningrad Oblast / [ed] Olli-Pekka Hilmola & Eugene Korovyakovsky, Lappeenranta University of Technology , 2009, p. 111-144Chapter in book (Other academic)
    Abstract [en]

    The ability of software applications to help solving logistics related problems has become of critical importance in general and bringing about productivity improvements in particular. This research is to scrutinize the role of IT solutions in this regard with warehouse systems in focus. According to the findings, software applications will contain increasing functionalities for training and guiding in finding and implementing novel logistics operational models with the goal of increasing return on investment with fewer resources. Intelligent automatically itself-adjusting service level agreement platforms might well be in the centre of focus of attention in the near future. The case study reveals that by synchronizing warehousing processes with advanced functionalities of a wms it becomes feasible to integrate strategic tactical considerations into operational matters in logistics decisions. In this manner it will be possible to enhance capacity utilization rates in executing processes despite large scale fluctuations in demand so as to increase responsiveness towards customers. In turn these factors will bring further simplicity and transparency into the contractual relations between the parties of a supply chain.

  • 575.
    Tadesse, Yohannes
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Using Edge-induced and Vertex-induced Subhypergraph Polynomials2015In: Mathematica Scandinavica, ISSN 0025-5521, E-ISSN 1903-1807, Vol. 117, no 2, p. 161-169Article in journal (Refereed)
    Abstract [en]

    For a hypergraph H, we consider the edge-induced and vertex-induced subhypergraph polynomials and study their relation. We use this relation to prove that both polynomials are reconstructible, and to prove a theorem relating the Hilbert series of the Stanley-Reisner ring of the independent complex of H and the edge-induced subhypergraph polynomial. We also consider reconstruction of some algebraic invariants of H.

  • 576.
    Tagami, Ayumu
    et al.
    KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, Stockholm, Sweden / Nippon Paper Industries Co., Ltd., Research Laboratory, Oji, Kita-ku, Tokyo, Japan.
    Gioia, Claudio
    KTH Royal Institute of Technology, WWSC-Wallenberg Wood Science Centre, Stockholm, Sweden / University of Bologna, Department of Civil, Chemical, Environmental, and Materials Engineering, Bologna, Italy.
    Lauberts, Maris
    Latvian State Institute of Wood Chemistry, Riga, Latvia.
    Budnyak, Tetyana
    KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, Stockholm, Sweden.
    Moriana, Rosana
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, Stockholm, Sweden / SLU-Swedish University of Agricultural Sciences, Molecular Sciences, Uppsala, Sweden.
    Lindström, Mikael E.
    KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, Stockholm, Sweden.
    Sevastyanova, Olena
    KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, Stockholm, Sweden / KTH Royal Institute of Technology, WWSC-Wallenberg Wood Science Centre, Stockholm, Sweden.
    Solvent fractionation of softwood and hardwood kraft lignins for more efficient uses: Compositional, structural, thermal, antioxidant and adsorption properties2019In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 129, p. 123-134Article in journal (Refereed)
    Abstract [en]

    This work summarizes the impact of solvent fractionation on the chemical structure, antioxidant activity, heating values, and thermal and adsorption properties of industrial hardwood and softwood kraft lignins. The aim of the research was to develop a simple approach for obtaining lignin fractions with tailored properties for applications in certain materials. Four common industrial solvents, namely, ethyl acetate, ethanol, methanol and acetone, in various combinations, were found to be efficient for separating spruce and eucalyptus kraft lignins into fractions with low polydispersities. The ethanol fraction of spruce and the ethyl acetate fraction of eucalyptus afforded the highest yields. Gel-permeation chromatography analysis was used to evaluate the efficiency of the chosen solvent combination for lignin fractionation. The composition and structure of the lignin material was characterized by elemental analysis, analytical pyrolysis (Py-GC/MS/FID) and 31P NMR spectroscopy. The thermal properties of the lignin samples were studied using thermogravimetric analysis. Proximate analysis data (ash, volatile components, organic matter and fixed carbon) was obtained through the direct measurement of weight changes in each experimental curve, and the high heating values (in MJ/kg) were calculated according to equations suggested in the literature. The adsorption properties of fractionated kraft lignins were studied using methylene blue dye. The correlations observed between molecular weight, composition and functionality and the thermal, radical scavenging and adsorption properties of the lignin fractions provides useful information for selecting the appropriate solvent combinations for specific applications of lignin raw materials (including their use as antioxidants, biofuels or sorbents in water treatment processes). © 2018

  • 577.
    Thorvald, Peter
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Comparing the use of article numbers to alternate information syntaxes2013In: Proceedings of NES 2013, 45th Nordic Ergonomics & Human Factors Society conference, Iceland, August 2013, 2013Conference paper (Refereed)
    Abstract [en]

    Using article numbers as identifiers in industry is a well-established practice. However, previous investigations have indicated, although failed to confirm, shortcomings in this tradition when used in human based assembly. This paper will report findings from an experimental study where subjects were asked to perform a reaction test designed to test the response to different types of syntaxes. These syntaxes where article numbers (control), symbols, and names of famous figures. Results show that subjects were able to significantly faster identify a trigger and respond accordingly when dealing with triggers with semantic content (symbols and names) than with article numbers.

  • 578.
    Thorvald, Peter
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Presenting Information in Manual Assembly2011Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Ever since industrialization, manufacturing companies have competed with each other in trying to make the best and the cheapest product and the automotive industry is definitely no exception. The ‘arms race’ between truck and car manufacturers has pushed manufacturing technology and production practice to where it is today. However, whereas companies have traditionally competed with the engineering excellence and technology of their products, the human effort in production is often neglected. After all, there are still many tasks that require the flexibility and intelligence of a human worker.

    This thesis focuses entirely on the information context of assembly workers. It investigates and discusses their general information behaviour in terms of information need, syntax of information, information sources and technology as well as basic cognitive abilities used to utilize information such as attention and memory. The thesis presents relevant literature on the subject of information behaviour and pinpoints potential hazards of information design in manual assembly. It also identifies three hypotheses that suggest improved productivity and quality of work as a result of certain changes in the information landscape. One hypothesis deals with the layout of information, a second deals with the syntax used to identify parts and a third deals with the information medium used to convey information.

    Analysis of empirical data gathered shows, among other things, that using unstructured and batched information favours productivity of work; using a syntax with semantic content as opposed to traditional article numbers without any semantic content also improves productivity of work; and using a mobile information unit betters the quality of work.

    The purpose of the thesis is to present the beginnings of a road map towards the greater understanding of information presentation in manual assembly. As previous research on this application area has been scarce, it draws upon existing theories found in other sciences, primarily cognitive science and its applications such as Human-Computer Interaction (HCI), information theory and human error.

    􀀁

  • 579.
    Thorvald, Peter
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Brolin, Anna
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Högberg, Dan
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Case, Keith
    Mechanical and Manufacturing Engineering, Loughborough University.
    Using Mobile Information Sources to Increase Productivity and Quality2010In: Proceedings of the 3rd Applied Human Factors and Ergonomics (AHFE) International Conference / [ed] Gavriel Salvendy, Waldemar Karwowski, Louisville: AHFE International , 2010Conference paper (Refereed)
    Abstract [en]

    This paper presents an experimental study made on the use of different kinds of information sources in manual assembly. The general idea is that only the necessary information should be presented to the worker and it should be presented where and when the worker needs it as this is believed to both save time and unload cognitive strain. To account for the latter two aspects of this thought, where and when, this paper investigates the use of a handheld unit as an information source in manual assembly. Having a mobile information system, such as a Personal Digital Assistant (PDA), that can be carried with you at all times, as opposed to a stationary one, such as a computer terminal, is hypothesized to greatly improve productivity and quality. Experimental results show that the use of a PDA significantly improves quality whereas productivity does not significantly improve.

  • 580.
    Thorvald, Peter
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Bäckstrand, Gunnar
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Högberg, Dan
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Case, Keith
    Loughborough University, Loughborough, UK.
    Syntax and Sequencing of Assembly Instructions2012In: Advances in Usability Evaluation: Part II / [ed] Francesco Rebelo & Marcelo M. Soares, CRC Press, 2012, p. 266-275Chapter in book (Refereed)
    Abstract [en]

    Minimalism of design is a concept often found in Human-computer interaction (HCI). It is a concept that emphasizes the presentation of as little information as possible to reduce the perceptual strain and visual search of the subject. However, in a manufacturing context, such as in manual assembly, state of the art information presentation is rarely minimalistic. Rather, organizations tend to push out as much information as possible without necessarily concerning themselves with how this information is presented to, or perceived by, the worker. This leads to a situation that is far from ideal from an HCI perspective, likely to reduce human performance and wellbeing, in turn negatively affecting overall production system performance. Obviously, there are several potential ways of addressing this issue. Perhaps the most evident way is to simply reduce the amount of information that is presented and only present the essentials. This paper will investigate and discuss how information presentation can be minimized without reducing the information content through information syntax and layout.

  • 581.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Case, KeithUniversity of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Loughborough University.
    Advances in Manufacturing Technology XXXII: Proceedings of the 16th International Conference on Manufacturing Research, Incorporating the 33rd National Conference on Manufacturing Research, September 11-13, 2018, University of Skövde, Sweden2018Conference proceedings (editor) (Refereed)
  • 582.
    Thorvald, Peter
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Högberg, Dan
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Case, Keith
    University of Skövde, The Virtual Systems Research Centre. Mechanical and Manufacturing Technology, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
    Applying cognitive science to digital human modelling for user centred design2012In: International Journal of Human Factors Modelling and Simulation, ISSN 1742-5549, Vol. 3, no 1, p. 90-106Article in journal (Refereed)
    Abstract [en]

    To build software which, at the press of a button, can tell you what cognition-related hazards there are within an environment or a task, is probably well into the future if it is possible at all. However, incorporating existing tools such as task analysis tools, interface design guidelines and information about general cognitive limitations in humans, could allow for greater evaluative options for cognitive ergonomics. The paper discusses previous approaches to the subject and suggests adding design and evaluative guiding in digital human modelling that will help a user with little or no knowledge of cognitive science to design and evaluate a human-product interaction scenario.

  • 583.
    Thorvald, Peter
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society. Loughborough University, Loughborough, United Kingdom.
    Högberg, Dan
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Case, Keith
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society. Loughborough University, Loughborough, United Kingdom.
    Incorporating Cognitive Aspects in Digital Human Modeling2009In: Digital Human Modeling: Second International Conference, ICDHM 2009, Held as Part of HCI International 2009, San Diego, CA, USA, July 19-24, 2009. Proceedings / [ed] Vincent G. Duffy, Berlin Heidelberg: Springer Berlin/Heidelberg, 2009, p. 323-332Conference paper (Refereed)
    Abstract [en]

    To build software which, at the press of a button, can tell you what cognition related hazards there are within an environment or a task, is probably well into the future if it is possible at all. However, incorporating existing tools such as task analysis tools, interface design guidelines and information about general cognitive limitations in humans, could allow for greater evaluative options for cognitive ergonomics. The paper will discuss previous approaches on the subject and suggest adding design and evaluative guiding in DHM that will help a user with little to no knowledge of cognitive science, design and evaluate a human-product interaction scenario.

  • 584.
    Thorvald, Peter
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science.
    Högberg, Dan
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science.
    Case, Keith
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science. Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, United Kingdom.
    The effect of information mobility on production quality2014In: International journal of computer integrated manufacturing (Print), ISSN 0951-192X, E-ISSN 1362-3052, Vol. 27, no 2, p. 120-128Article in journal (Refereed)
    Abstract [en]

    This article investigates the use of a hand-held unit as an information source in manual assembly. Having a mobile information system, such as a Personal Digital Assistant (PDA), that can be brought at all times, as opposed to a stationary one, such as a computer terminal, is hypothesised to increase the information range and thus improves assembly performance. The increased information range is argued to be due to assembly workers employing a cost-benefit strategy, where the cost of gathering information is compared with the assumed benefit of it. This article reports empirical data comparing the use of a mobile information carrier with a traditional stationary computer, and results show that the use of a PDA significantly improves quality, whereas productivity does not significantly improve quality. © 2013 Copyright Taylor & Francis.

  • 585.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Distributed cognition at work - A systemic perspective on human based manufacturing2015In: Proceedings of ICMR 2015 / [ed] Linda Newnes, Aydin Nassehi & Vimal Dhokia, Bath, UK: University of Bath , 2015, p. 195-200Conference paper (Refereed)
    Abstract [en]

    Cognitive science is becoming increasingly central within human factors & ergonomics and, since at the same time, there has long been a call for a more systemic perspective in the area with a somewhat wider unit of analysis, this paper argues that the theoretical framework of distributed cognition would greatly benefit the area. It would offer a more complete understanding of the user within a greater context, be it social, cultural or materialistic. This paper aims to characterize and analyse the domain of manufacturing as a complex socio-technical system from a distributed cognition perspective; focusing on the use, mediation and integration of different forms of representations, tools and artefacts in this domain.  The paper further proposes and exemplifies benefits of using a distributed cognition framework in the manufacturing domain as studied by human factors and ergonomics.

  • 586.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Initial development of a cognitive load assessment tool2014In: Advances in Cognitive Engineering and Neuroergonomics / [ed] Kay Stanney & Kelly S. Hale, AHFE , 2014, p. 223-232Conference paper (Refereed)
    Abstract [en]

    Interest in cognitive or mental workload has over the last couple of years increased drastically from a manufacturing application perspective.  More and more, people are becoming aware of the cognitive limitations that may have great impact on production outcome. The more easily observable area of physical ergonomics has been successfully investigated for a long time and it would seem as though focus has broadened to also include cognitive ergonomics. Considering the effects that a large cognitive load has on human performance, knowledge regarding the role of the cognizing human in a manufacturing environment could potentially have significant effect on production outcome (i.e. quality and productivity). With this in mind, developing and using methods and tools for assessment of the cognitive burden associated with particular tasks or workstations should be and is of substantial interest to the manufacturing industry. Whatever assessment methods exist in the scientific literature today are almost exclusively expert tools where significant expertise in the area of cognitive ergonomics/psychology/science is required. This paper reports parts of the development process and initial version of a non-expert tool for assessment of cognitive load in manual production environments, primarily manual assembly.

  • 587.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Virtual Systems Research Centre.
    Andreasson, Rebecca
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre. Uppsala Universitet.
    CLAM – A method for cognitive load assessment in manufacturing2017In: Advances in Manufacturing Technology XXXI / [ed] Gao, J., El Souri, M., Keates, S., Amsterdam: IOS Press, 2017, Vol. 6, p. 114-119Conference paper (Refereed)
    Abstract [en]

    The increasing complexity and demands of assembly operations in manufacturing has been shown to lead to increased cognitive load in assembly workers. Previous work has outlined the complexity of an assembly worker’s situation both in terms of difficulty and speed of work and there have been a few attempts at creating frameworks and methods for understanding the key aspects of what creates increased cognitive load. This paper presents a tool for assessing cognitive load in manufacturing, primarily assembly. The paper presents the method and an accompanying tool as well as some insights derived from this method development. The intended contribution of the work is to make a difference in reducing the cognitive load of assembly workers on the shop floor, thus focusing the development on applicability and usability of the tool in practice. 

  • 588.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Andreasson, Rebecca
    Uppsala University, Department of Information Technology, Uppsala, Sweden.
    On the development of a method for cognitive load assessment in manufacturing2019In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 59, p. 252-266Article in journal (Refereed)
    Abstract [en]

    The increasing complexity and demands of assembly operations in manufacturing has been shown to lead to increased cognitive load in assembly workers. Previous work has outlined the complexity of an assembly worker's situation both in terms of difficulty and speed of work and there have been a few attempts at creating frameworks and methods for understanding the key aspects of what creates increased cognitive load. This paper presents the development of an analytic method, denoted CLAM (Cognitive Load Assessment for Manufacturing), and a tool for assessing cognitive load in manufacturing, primarily assembly. It outlines the journey of the development as well as discusses and problematizes relevant meta-methodological issues paired with method development. The intended contribution of the work is to make a difference in reducing the cognitive load of assembly workers on the shop floor, thus focusing the development on applicability and usability of the tool in practice. With this purpose in mind, focus of the method development has been on the practitioners, i.e. the method should not require any expert knowledge to be applied. The CLAM method and accompanying documentation such as a handbook containing instructions towards using the method and interpreting the results, is available in an online tool.

  • 589.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Chalmers University of Technology, Gothenburg, Sweden.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Kolbeinsson, Ari
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Embodied Interactions in Cognitive Manufacturing2020In: Advances in Neuroergonomics and Cognitive Engineering: Proceedings of the AHFE 2019 International Conference on Neuroergonomics and Cognitive Engineering, and the AHFE International Conference on Industrial Cognitive Ergonomics and Engineering Psychology, July 24-28, 2019, Washington D.C., USA / [ed] Hasan Ayaz, Springer, 2020, p. 419-426Conference paper (Refereed)
    Abstract [en]

    This paper presents a discussion on the role of embodied interaction with a basis in social embodiment effects and how they can be viewed in light of manufacturing ergonomics. The social embodiment effects are four statements, grounded in empirical findings, which highlight the interplay of social stimuli, embodied responses, and cognitive processing. They suggest and base an argument for how embodiment is central to cognitive processing, how bodily states interact extensively with cognitive states, and ultimately how embodied interaction is ubiquitous in human cognition. The paper further presents a view on how human based manufacturing can be studied in light of this argument, exploring other areas where social embodiment has been further researched, with an aim to suggest examples of where social embodiment effects might be found in manufacturing ergonomics and form a basis for future investigations. 

  • 590.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Schmitz, Sebastian
    FIR at RWTH Achen, Germany.
    Modified pluralistic walkthrough for method evaluation in manufacturing2015In: Procedia Manufacturing, ISSN 2351-9789, Vol. 3, p. 5139-5146Article in journal (Refereed)
    Abstract [en]

    This paper presents a mixed evaluation design including quantitative and qualitative datain order to validate the scope, validity, and reliability of a recently developed CLAM method and tool. A central part of the evaluation was the use of a modified pluralistic walkthroughthat was created to better suit the industrial domain. The evaluation of CLAM was performed in a demonstration factory focusing on manufacturing of street scooters and electric pedal cars. The modified walkthrough was conducted on the shop floor, during on-going assembly, which stresses the representativeness of a real-world setting of manufacturing. The modified pluralistic walkthrough functioned accurately as an evaluation method of CLAM and the exhaustive comments and data from the user representatives were very beneficial. The quantitative results show convicting evidence of CLAM’s utility for assessing cognitive load while the qualitative results indicate that some modifications have to be made in order to enhance the actual tool in order to avoid misinterpretations resulting in misleading outcomes.

  • 591.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Universitat Autònoma de Barcelona, Barcelona, Spain.
    Stokes, Klara
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    An Overview of the Use of Clustering for Data Privacy2016In: Unsupervised Learning Algorithms / [ed] M. Emre Celebi, Kemal Aydin, Springer, 2016, p. 237-251Chapter in book (Refereed)
    Abstract [en]

    In this chapter we review some of our results related to the use of clustering in the area of data privacy. The paper gives a brief overview of data privacy and, more specifically, on data driven methods for data privacy and discusses where clustering can be applied in this setting. We discuss the role of clustering in the definition of masking methods, and on the calculation of information loss and data utility.

  • 592.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Universitat Autònoma de Barcelona, Campus UAB, Bellaterra, Spain.
    Stokes, Klara
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Data privacy2019In: Data science in Practice / [ed] Alan Said, Vicenç Torra, Springer, 2019, p. 121-132Chapter in book (Refereed)
    Abstract [en]

    In this chapter we present an overview of the topic data privacy. We review privacy models and measures of disclosure risk. These models and measures provide computational definitions of what privacy means, and of how to evaluate the privacy level of a data set. Then, we give a summary of data protection mechanisms. We provide a classification of these methods according to three dimensions: whose privacy is being sought, the computations to be done, and the number of data sources. Finally, we describe masking methods. Such methods are the data protection mechanisms used for databases when the data use is undefined and the protected database is required to be useful for several data uses. We also provide a definition of information loss (or data utility) for this type of data protection mechanism. The chapter finishes with a summary.

  • 593.
    Ujvari, Sandor
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Proceedings of the Plan Research Conference2010Conference proceedings (editor) (Other academic)
  • 594.
    Ujvari, Sandor
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Hilmola, Olli-Pekka
    Kouvola Research Unit, Lappeenranta University of Technology, Kouvola, Finland.
    Semi-autonomous vehicles with routing flexibility: functionality and application areas2009In: International Journal of Services and Operations Management, ISSN 1744-2370, Vol. 5, no 4, p. 444-462Article in journal (Refereed)
    Abstract [en]

    Automated Guided Vehicle (AGV) systems are standard automated items in production and warehousing today. However, studies have rarely examined a more advanced form of AGVs called Semi-Autonomous Vehicles (SAVs), which have a higher sophistication of task completion and routing flexibility. This research presents SAVs in an industrial development case study. Using simulation, the route-keeping ability of SAVs with two types of guidance techniques is being studied. The results show that dual-navigation SAVs can provide the needed flexibility for routing. Using wire guidance and dead reckoning, both very well-established techniques, the SAVs' performance is, within certain limits, quite comparable to the AGVs with more advanced and expensive navigation techniques.

  • 595.
    Ulfat, I.
    et al.
    Department of Physics, University of Karachi, Pakistan.
    Kanski, J.
    Chalmers University of Technology, Göteborg, Sweden.
    Ilver, L.
    Chalmers University of Technology, Göteborg, Sweden.
    Sadowski, J.
    MAX-IV laboratory, Lund University, Sweden.
    Karlsson, Krister
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ernst, A.
    Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany / Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Germany.
    Sandratskii, L.
    Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany.
    Effects of nonuniform Mn distribution in (Ga,Mn)As2014In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 89, no 4, p. 1-5, article id 045312Article in journal (Refereed)
    Abstract [en]

    Resonant in situ photoemission from Mn 3d states in Ga(1−x)MnxAs is reported for Mn concentrations down to the very dilute level of 0.1%. Concentration-dependent spectral features are analyzed on the basis of first-principles calculations for systems with selected impurity positions as well as for random alloys. Effects of direct Mn-Mn interaction are found for concentrations as low as 2.5%, and are ascribed to statistical (nonuniform) distribution of Mn atoms.

  • 596.
    Urenda Moris, Matias
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Svensson, Jacob
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Simplification and aggregation strategies applied for factory analysis in conceptual phase using simulation2008In: Proceedings of the 2008 Winter Simulation Conference, IEEE conference proceedings, 2008, p. 1913-1921Conference paper (Refereed)
  • 597.
    Urenda Moris, Matías
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Dealing with variability in the design, planning and evaluation of Healthcare inpatient units: a modelling methodology for patient dependency variations2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This research addresses the fluctuating demand and high variability in healthcare systems. These system’s variations need to be considered whilst at the same time making efficient use of the systems’ resources. Patient dependency fluctuation, which makes determining the level of adequate staffing highly complex, is among the variations addressed. Dealing with variability is found to be a key feature in the design, planning and evaluation of healthcare systems.

    Healthcare providers are facing increasing challenges resulting from an aging population, higher patient expectancies, a shortage of healthcare professionals, as well as increasing costs and reduced funding. Despite the accentuated need for effective healthcare systems and efficient use of resources, many healthcare organisations are inadequately designed and, moreover, poorly managed. Hospital systems consist of complex interrelations between relatively small units, each of which is sensitive to stochastic variations in demand. In addition to this aspect of the system view, a critical resource for the patients’ wellbeing and survival is the staffing level of nurses. This puts the planning and scheduling of human resources as one of the system’s foremost aims. Current tools for staffing and personnel planning in healthcare organisations do not take into consideration the workload variations that result from the variable nature of patient dependency levels.

    The work presents the empirical findings of a number of case studies conducted at a regional hospital in Sweden. Principles and practical suggestions for the robust system design of inpatient wards using Discrete Event Simulation (DES) have been identified. Although DES techniques have, in principle, all the features for modelling the variation and stochastic nature of systems, DES has not been previously used for workload studies of inpatient wards. The main contribution of this work is therefore how a combination of DES and the data of Patient Classification Systems (PCSs) can be used to model workload variations and, subsequently, plan the nurse staffing requirements in systems with high variability. The work presented gives step by step guidance in how the analysis and subsequent modelling of an inpatient ward should be carried out. It defines a novel modelling methodology for patient dependency variations and length of stay modelling of a patient’s dependency progression, including an adaptation to the ward’s discharge figures. The modelling approach opens a novel way of analysing and evaluating the system design of inpatient wards.

  • 598.
    Urenda Moris, Matías
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos H. C.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Bernedixen, Jacob
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Goienetxea, Ainhoa
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Diseño Y Análisis De Sistemas Productivos Utilizando La Optimización Mediante Simulación Basado En Internet2012In: Ingenieria Industrial, ISSN 0717-9103, E-ISSN 0718-8307, Vol. 11, no 1, p. 37-49Article in journal (Other academic)
  • 599.
    Urenda Moris, Matías
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos H. C.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Bernedixen, Jacob
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Goienetxea Uriarte, Ainhoa
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Diseño Y Análisis De Sistemas Productivos Utilizando La Optimización Mediante Simulación Basado En Internet2011Conference paper (Refereed)
  • 600.
    Walander, Tomas
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Cohesive modelling of the temperature dependence of epoxy based adhesives in Mode I and Mode II loading2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this work, the influence of the temperature on the cohesive laws for two epoxy adhesives is studied at temperatures below the glass transition temperature for both Mode I and Mode II loading. Cohesive laws are measured experimentally under quasi-static loading conditions in the temperature range -30≤T≤80"C" . Three parameters of the cohesive laws are studied in detail: the elastic stiffness, the peak stress and the fracture energy. Methods for determining the elastic stiffness in Mode I and Mode II are derived and evaluated. With these methods, the results in this work show that it is possible to measure all three parameters for each pure mode loading case by the use of only the DCB- and the ENF-test specimens. Even though the measures tend to spread in values, this can significantly reduce the cost for performing experiments. It is shown that most of the cohesive parameters are decreasing with an increasing temperature in both loading modes and for both adhesives. An exception is the Mode I fracture energy for one of the adhesives. This is shown to be independent of the temperature in the studied temperature range. For the same adhesive, the Mode II fracture energy is shown to be continuously decreasing with an increasing temperature. The experimental results are verified by finite element analyses. The simulations only consider uncoupled cohesive behaviours. By use of the experimental results, simplified bi-linear cohesive laws to be used at any temperature within the studied temperature range are derived for one adhesive in both loading modes. This is desired in order to simulate adhesively bonded structures that suffer a wide range in temperature.

91011121314 551 - 600 of 661
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