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  • 1501.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Bandaru, Sunith
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Virtual Factories with Knowledge-Driven Optimization as a New Research Profile2020In: SPS2020: Proceedings of the Swedish Production Symposium, October 7–8, 2020 / [ed] Kristina Säfsten; Fredrik Elgh, IOS Press, 2020, p. 179-189Conference paper (Refereed)
    Abstract [en]

    This paper conceptually introduces VF-KDO (Virtual Factories with Knowledge-Driven Optimization, a research profile of the University of Skovde, Sweden, which is underway from 2018-2026. The goal of this research profile is to deliver radical innovations in manufacturing research essential to the design and operation of next-generation manufacturing systems. A unique concept proposed in VF-KDO is: knowledge extracted for decision support is achieved through systematically exploring, e.g., using advanced, interactive data analytics techniques on optimal solutions generated via many-objective optimizations on virtual factory models. As the word 'driven' means 'motivated' or 'manipulated', so does KDO have some two-fold meanings: (1) optimizations that aim at generating knowledge, not only mathematically optimal solutions; (2) knowledge-controlled optimizations, instead of some blind/black-box processes. It is this concept of KDO, combining with modular, virtual factory models at different levels, which distinguishes VF-KDO from other related research efforts found internationally and in Sweden. The cutting-edge research topics involved in the research profile and their synergy with the digitalization efforts of the 7 partner companies, in form of the development of an intelligent decision support system, can be used to improve the competiveness of the Swedish manufacturing industry by supporting their holistic, optimal and sustainable decision making. 

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  • 1502.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Bernedixen, Jacob
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Andersson, Martin
    University of Skövde, School of Engineering Science.
    Bandaru, Sunith
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment. Virtuella fabriker VF-KDO.
    Lezama, Thomas
    Modelling Simulation Airbus Group, Toulouse, France.
    Aircraft Assembly Ramp-Up Planning Using a Hybrid Simulation-Optimization Approach2020In: Proceedings - Winter Simulation Conference / [ed] K.-H. Bae; B. Feng; S. Kim; S. Lazarova-Molnar; Z. Zheng; T. Roeder; R. Thiesing, IEEE, 2020, p. 3045-3056Conference paper (Refereed)
    Abstract [en]

    Assembly processes have the most influencing and long-term impact on the production volume and cost in the aerospace industry. One of the most crucial factors in aircraft assembly lines design during the conceptual design phase is ramp-up planning that synchronizes the production rates at the globally dispersed facilities. Inspired by a pilot study performed with an aerospace company, this paper introduces a hybrid simulation-optimization approach for addressing an assembly production chain ramp-up problem that takes into account: (1) the interdependencies of the ramp-up profiles between final assembly lines and its upstream lines; (2) workforce planning with various learning curves; (3) inter-plant buffer and lead-time optimization, in the problem formulation. The approach supports the optimization of the ramp-up profile that minimizes the times the aircraft assemblies stay in the buffers and simultaneously attains zero backlog. It also generates the required simulation-optimization data for supporting the decision-making activities in the industrialization projects. 

  • 1503.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Bernedixen, Jacob
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Volvo Car Corporation, Sweden.
    Pehrsson, Leif
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Volvo Car Corporation, Sweden.
    What Does Multi-Objective Optimization Have to Do with Bottleneck Improvement of Production Systems?2014In: Proceedings of The 6th International Swedish Production Symposium 2014 / [ed] Johan Stahre, Björn Johansson & Mats Björkman, 2014Conference paper (Refereed)
    Abstract [en]

    Bottleneck is a common term used to describe the process/operation/person that constrains the performance of the whole system. Since Goldratt introduced his theory of constraint, not many will argue about the importance of identifying and then improving the bottleneck, in order to improve the performance of the entire system. Nevertheless, there exist various definitions of bottleneck, which make bottleneck identification and improvement not a straightforward task in practice. The theory introduced by Production Systems Engineering (PSE) that the bottleneck of a production line is where the infinitesimal improvement can lead to the largest improvement of the average throughput, has provided an inspirational and rigorous way to understand the nature of bottleneck. This is because it conceptually puts bottleneck identification and improvement into a single task. Nevertheless, it is said that a procedure to evaluate how the efficiency increase of each machine would affect the total performance of a line is hardly possible in most practical situations. But is this true?In this paper, we argue how multi-objective optimization fits nicely into the theory introduced by PSE and hence how it can be developed into a practical bottleneck improvement methodology. Numerical results from a real-world application study on a highly complex machining line are provided to justify the practical applicability of this new methodology.

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  • 1504.
    Ng, Amos H. C.
    et al.
    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.
    Syberfeldt, Anna
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    A comparative study of production control mechanisms using simulation-based multi-objective optimisation2012In: International Journal of Production Research, ISSN 0020-7543, E-ISSN 1366-588X, Vol. 50, no 2, p. 359-377Article in journal (Refereed)
    Abstract [en]

    There exist many studies conducted to compare the performance of different production control mechanisms (PCMs) in order to determine which one performs the best under different conditions. Nonetheless, most of these studies suffer from the problems that the PCMs are not compared with their optimal parameter settings in a truly multi-objective context. This paper describes how different PCMs can be compared under their optimal settings through generating the Pareto-optimal frontiers, in the form of optimal trade-off curves in the performance space, by applying evolutionary multi-objective optimisation to simulation models. This concept is illustrated with a bi-objective comparative study of the four most popular PCMs in the literature, namely Push, Kanban, CONWIP and DBR, on an unbalanced serial flow line in which both control parameters and buffer capacities are to be optimised. Additionally, it introduces the use of normalised hyper-volume as the quantitative metric and confidence-based significant dominance as the statistical analysis method to verify the differences of the PCMs in the performance space. While the results from this unbalanced flow line cannot be generalised, it indicates clearly that a PCM may be preferable in certain regions of the performance space, but not others, which supports the argument that PCM comparative studies have to be performed within a Pareto-based multi-objective context.

  • 1505.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Dudas, Catarina
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Nießen, Johannes
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Deb, Kalyanmoy
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Simulation-Based Innovization Using Data Mining for Production Systems Analysis2011In: Multi-objective Evolutionary Optimisation for Product Design and Manufacturing / [ed] Lihui Wang, Amos H. C. Ng, Kalyanmoy Deb, Springer London, 2011, p. 401-429Chapter in book (Refereed)
    Abstract [en]

    This chapter introduces a novel methodology for the analysis and optimization of production systems. The methodology is based on the innovization procedure, originally introduced for unveiling new and innovative design principles in engineering design problems. Although the innovization method is based on multi-objective optimization and post-optimality analyses of optimised solutions, it stretches the scope beyond an optimization task and attempts to discover new design/operational rules/principles relating to decision variables and objectives, so that a deeper understanding of the problem can be obtained. By integrating the concept of innovization with discrete-event simulation and data mining techniques, a new set of powerful tools can be developed for general systems analysis, particularly suitable for production systems. The uniqueness of the integrated approach proposed in this chapter lies on applying data mining to the data sets generated from simulation-based multi-objective optimization, in order to automatically or semi-automatically discover and interpret the hidden relationships and patterns for optimal production systems design/reconfiguration.

  • 1506.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Shaaban, Sabry
    Department of Strategy, ESC La Rochelle, La Rochelle, France.
    Bernedixen, Jacob
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Studying unbalanced workload and buffer allocation of production systems using multi-objective optimisation2017In: International Journal of Production Research, ISSN 0020-7543, E-ISSN 1366-588X, Vol. 55, no 24, p. 7435-7451Article in journal (Refereed)
    Abstract [en]

    Numerous studies have investigated the effects of unbalanced service times and inter-station buffer sizes on the efficiency of discrete part, unpaced production lines. There are two main disadvantages of many of these studies: (1) only some predetermined degree of imbalance and patterns of imbalance have been evaluated against the perfectly balanced configuration, making it hard to form a general conclusion on these factors; (2) only a single objective has been set as the target, which neglects the fact that different patterns of imbalance may outperform with respect to different performance measures. Therefore, the aim of this study is to introduce a new approach to investigate the performance of unpaced production lines by using multiple-objective optimisation. It has been found by equipping multi-objective optimisation with an efficient, equality constraints handling technique, both the optimal pattern and degree of imbalance, as well as the optimal relationship among these factors and the performance measures of a production system can be sought and analysed with some single optimisation runs. The results have illustrated that some very interesting relationships among the key performance measures studied, including system throughput, work-in-process and average buffer level, could only be observed within a truly multi-objective optimisation context. While these results may not be generalised to apply to any production lines, the genericity of the proposed simulation-based approach is believed to be applicable to study any real-world, complex production lines.

  • 1507.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Siegmund, Florian
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Deb, Kalyanmoy
    Michigan State University, East Lansing, Michigan, USA.
    Reference point based evolutionary multi-objective optimization with dynamic resampling for production systems improvement2018In: Journal of Systems and Information Technology, ISSN 1328-7265, E-ISSN 1758-8847, Vol. 20, no 4, p. 489-512Article in journal (Refereed)
    Abstract [en]

    Purpose

    Stochastic simulation is a popular tool among practitioners and researchers alike for quantitative analysis of systems. Recent advancement in research on formulating production systems improvement problems into multi-objective optimizations has provided the possibility to predict the optimal trade-offs between improvement costs and system performance, before making the final decision for implementation. However, the fact that stochastic simulations rely on running a large number of replications to cope with the randomness and obtain some accurate statistical estimates of the system outputs, has posed a serious issue for using this kind of multi-objective optimization in practice, especially with complex models. Therefore, the purpose of this study is to investigate the performance enhancements of a reference point based evolutionary multi-objective optimization algorithm in practical production systems improvement problems, when combined with various dynamic re-sampling mechanisms.

    Design/methodology/approach

    Many algorithms consider the preferences of decision makers to converge to optimal trade-off solutions faster. There also exist advanced dynamic resampling procedures to avoid wasting a multitude of simulation replications to non-optimal solutions. However, very few attempts have been made to study the advantages of combining these two approaches to further enhance the performance of computationally expensive optimizations for complex production systems. Therefore, this paper proposes some combinations of preference-based guided search with dynamic resampling mechanisms into an evolutionary multi-objective optimization algorithm to lower both the computational cost in re-sampling and the total number of simulation evaluations.

    Findings

    This paper shows the performance enhancements of the reference-point based algorithm, R-NSGA-II, when augmented with three different dynamic resampling mechanisms with increasing degrees of statistical sophistication, namely, time-based, distance-rank and optimal computing buffer allocation, when applied to two real-world production system improvement studies. The results have shown that the more stochasticity that the simulation models exert, the more the statistically advanced dynamic resampling mechanisms could significantly enhance the performance of the optimization process.

    Originality/value

    Contributions of this paper include combining decision makers’ preferences and dynamic resampling procedures; performance evaluations on two real-world production system improvement studies and illustrating statistically advanced dynamic resampling mechanism is needed for noisy models.

  • 1508.
    Ng, Amos H. C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Syberfeldt, AnnaUniversity of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.Högberg, DanUniversity of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.Holm, MagnusUniversity of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    SPS2022: Proceedings of the 10th Swedish Production Symposium2022Conference proceedings (editor) (Refereed)
    Abstract [en]

    The realization of a successful product requires collaboration between developers and producers, taking account of stakeholder value, reinforcing the contribution of industry to society and enhancing the wellbeing of workers while respecting planetary boundaries. Founded in 2006, the Swedish Production Academy (SPA) aims to drive and develop production research and education and to increase cooperation within the production area.

    This book presents the proceedings of the 10th Swedish Production Symposium (SPS2022), held in Skövde, Sweden, from 26-29 April 2022. The overall theme of the symposium was ‘Industry 5.0 Transformation – Towards a Sustainable, Human-Centric, and Resilient Production’. Since its inception in 2007, the purpose of SPS has been to facilitate an event at which members and interested participants from industry and academia can meet to exchange ideas. The 69 papers accepted for presentation here are grouped into ten sections: resource-efficient production; flexible production; humans in the production system; circular production systems and maintenance; integrated product and production development; industrial optimization and decision-making; cyber-physical production systems and digital twins; innovative production processes and additive manufacturing; smart and resilient supply chains; and linking research and education. Also included are three sections covering the Special Sessions at SPS2022: artificial intelligence and industrial analytics in industry 4.0; development of resilient and sustainable production systems; and boundary crossing and boundary objects in product and production development.

    The book will be of interest to all those involved in the development and production of future products.

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  • 1509. Ng, Amos H. C.
    et al.
    Urenda Moris, Matias
    Svensson, Jacob
    Multi-Objective Simulation Optimization for Production Systems Design using FACTS Analyser2008In: Proceedings of the 2nd Swedish Production Symposium, 2008, p. 101-109Conference paper (Refereed)
    Abstract [en]

    This paper proposes a new general method for supporting production systems design within the context of Multi-objective Simulation Optimisation. Under this framework, different Production Control Mechanisms can be compared based on their optimal settings, which will be illustrated with a pedagogical simple flow line as well as an engines assembly line in automotive industry. Results from these case studies have provided significant insight into the importance of applying MOSO for Multi-Criteria Decision Making in general production systems design. At the same time, it also outlines the concept of applying significant dominance to handle uncertainty from stochastic simulation output, which has been implemented into a Web-based DES system called FACTS Analyser, specifically designed for conceptual factory design, analysis and optimisation.

  • 1510.
    Ng, Amos H.C.
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. School of Engineering, Jönköping University, Sweden .
    Bandaru, Sunith
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Frantzén, Marcus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Volvo Car Corporation, Sweden .
    Innovative Design and Analysis of Production Systems by Multi-objective Optimization and Data Mining2016In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 50, p. 665-671Article in journal (Refereed)
    Abstract [en]

    This paper presents an innovative approach for the design and analysis of production systems using multi-objective optimization and data mining. The innovation lies on how these two methods using different computational intelligence algorithms can be synergistically integrated and used interactively by production systems designers to support their design decisions. Unlike ordinary optimization approaches for production systems design which several design objectives are linearly combined into a single mathematical function, multi-objective optimization that can generate multiple design alternatives and sort their performances into an efficient frontier can enable the designer to have a more complete picture about how the design decision variables, like number of machines and buffers, can affect the overall performances of the system. Such kind of knowledge that can be gained by plotting the efficient frontier cannot be sought by single-objective based optimizations. Additionally, because of the multiple optimal design alternatives generated, they constitute a dataset that can be fed into some data mining algorithms for extracting the knowledge about the relationships among the design variables and the objectives. This paper addresses the specific challenges posed by the design of discrete production systems for this integrated optimization and data mining approach and then outline a new interactive data mining algorithm developed to meet these challenges, illustrated with a real-world production line design example.

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  • 1511.
    Ng, Amos H.C.
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science.
    Skoogh, Anders
    Chalmers University of Technology, Gothenburg, Sweden.
    Lämkull, Dan
    Volvo Car Corporation, Gothenburg, Sweden.
    Optimal Maintenance Resources Allocation Using Automated Simulation-based Optimisation and Data Management2015In: Simulation in Production and Logistics 2015 / [ed] Markus Rabe, Uwe Clausen, Stuttgart: Fraunhofer IRB Verlag, 2015, p. 437-446Conference paper (Refereed)
    Abstract [en]

    This paper introduces a Streamlined Modelling and Decision Support (StreaMod) approach in which input data management, simulation model generation/update and simulation-based optimisation are synergistically integrated into a largely automated process. The aim of this automated process is to support decision making related to the optimal maintenance resources allocation that could improve the performance of production/logistics systems. The basic novelty of the StreaMod optimisation methodology lies on the formulation of an optimal maintenance allocation problem of a production/logistic system into a bi-objective optimisation problem, so that optimal resources/changes to improve the throughput of the system can be sought in a single optimisation run. The successful application of this methodology in a real-world automotive factory will also be addressed in this paper.

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    Optimal Maintenance Resources Allocation Using Automated Simulation-based Optimisation and Data Management
  • 1512.
    Ng, Amos
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Jägstam, Mats
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Pehrsson, Leif
    Volvo Car Corporation.
    Deb, Kalyanmoy
    Indian Institute of Technology Kanpur, India.
    Improving Factory Productivity and Energy Efficiency Through Holistic Simulation Optimisation2011In: The 21st International Conference on Multiple Criteria Decision Making, University of Jyväskylä , 2011, p. 235-Conference paper (Refereed)
    Abstract [en]

    There is an urgent need for the automotive inductry to explore strategies and methods to accelerate the industrial efficiency progress and support decision making in order to regain profitability. At the same time, decision making should not be made strictly from a view of productivity and investment cost. Manufactures worldwide are taking steps towards more sustainable manufacturing. Sustainability, in terms of "Energy Efficiency", "Lean", "Lead Time Efficiency" and other forms of reuse/conservation of resources has become a paramount factor that needs to be considered not only during the operational stage but from the very first day a production system is designed or configured. Therefore, to optimise a manufacturing system today is not only about maximising capacity and minimising costs, it is also about minimising energy use, minimising loss, minimising manufacturing lead time and other sustainability measures. The aim of the presentation is to introduce an innovative simulation-based optimisation and knowledge elicitation methodology for decision-making support within the production systems lifecycle to increase the profitability (increasing cost effectiveness) and simultaneously sustainability (increasing energy efficiency, reducing losses/wastes and shorten Order to Delivery Time) of the Swedish manufacturing industry. The methodology is so called Holistic Simulation Optimisation (HSO) because unlike today's industrial practice that productivity, cost and sustainability are optimised separately, the framework proposed takes into account productivity, cost, and sustainability in a multi-level and multi-objective context. The HSO methodology is realised through the development of a software toolset that synergistically integrates Discrete Event Simulation with the sustainability and cost models that have been developed or extended by industrial companies with state-of-the-art multi-objective optimisation and data mining technologies. The potential benefits of using the HSO methodology on the efficiency of the production systems that are measurable and can be verified quantitatively are: 5-15% increase in productivity; 10-20% reduction in manufacturing lead time; reduction in environmental wastes, in terms of energy use and other forms of losses (10-20%). The paper will present how these estimations are based on the case studies conducted in Swedish automotive industry.

  • 1513.
    Ng, Amos
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Persson, Jacob
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Urenda Moris, Matias
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Introducing Simulation-based Optimization for Production Systems Design to Industry: the FACTS Game2008In: Proceedings of the 18th International Conference on Flexible Automation and Intelligent Manufacturing: FAIM 2008, June 30th – July 2nd, 2008 University of Skövde, Sweden, Skövde: University of Skövde , 2008, p. 1359-1372Conference paper (Refereed)
  • 1514.
    Ng, Amos
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Syberfeldt, Anna
    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.
    Svensson, Jacob
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Multi-Objective Simulation Optimization and Significant Dominance for Comparing Production Control Mechanisms2008In: Proceedings of the 18th International Conference on Flexible Automation and Intelligent Manufacturing, Skövde, Sweden, 2008, Skövde: University of Skövde , 2008Conference paper (Refereed)
  • 1515.
    Ng, Amos
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Urenda Moris, Matias
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Jägstam, Mats
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Svensson, Jacob
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    An Internet-Enabled Tool for Multi-Objective Simulation Optimization2009In: OPTIMA 2009: VIII Congreso Chileno de Investigacion Operativa, 2009Conference paper (Refereed)
  • 1516.
    Ng, Tan Ching
    et al.
    Department of Mechanical and Material Engineering, Universiti Tunku Abdul Rahman, Kajang, Malaysia.
    Lau, Sie Yee
    Department of Mechanical and Material Engineering, Universiti Tunku Abdul Rahman, Kajang, Malaysia ; Mechanical Engineering Programme, University of Technology Sarawak, Sibu, Malaysia.
    Ghobakhloo, Morteza
    School of Economics and Business, Kaunas University of Technology, Lithuania ; Graduate School of Business, Universiti Sains Malaysia, Gelugor, Malaysia.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment. Division of Industrial Engineering and Management, Uppsala University, Sweden.
    Liang, Meng Suan
    Department of Mechanical and Material Engineering, Universiti Tunku Abdul Rahman, Kajang, Malaysia.
    The Application of Industry 4.0 Technological Constituents forSustainable Manufacturing: A Content-Centric Review2022In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 7, p. 1-21, article id 4327Article, review/survey (Refereed)
    Abstract [en]

    Industry 4.0 has been associated with the rise of disruptive intelligence and informationtechnologies. These cutting-edge technologies have the potential to increase productivity whilesimultaneously having a significant impact on social and environmental sustainability. As a result,manufacturers must evaluate the role of these innovative technologies in sustainable development,as these technologies have the potential to address prevalent sustainability issues. A content-centricstudy of the implementation of these Industry 4.0 cutting-edge technologies in sustainable manufacturing is currently absent. A systematic literature study was conducted to explain the potentialcontribution of these novel technologies to the economic, social, and environmental dimensions ofmanufacturing industries. This study describes how these cutting-edge technologies are used insustainable manufacturing. The findings of this study are particularly beneficial to practitioners whoseek to apply one or more digital technologies to sustainable development.

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  • 1517.
    Nicolás García, Ginés
    et al.
    University of Skövde, School of Engineering Science.
    Fernández Díez, Martín
    University of Skövde, School of Engineering Science.
    Evaluation of interior truck ergonomics through a digital twin approach2022Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Industries of today are constantly making changes and advancing towards a future with the purpose of innovation, improvement and sustainability. New technologies give the opportunities to make advantages in a number of fields and adapt new methodologies to their processes and products; in this project, we are going to study the application of digital twins in the automotive sector, focusing on the ergonomic evaluation of an interior truck cabin by using motion capture system and DHM tools.A number of 6 participants have been tested with Xsens motion capture performing different tasks related to reachability, storage and comfort inside the truck cabin. Their actions get recorded and implemented in an evaluation software called ScaleFit, which provides numerical results for several parts of the body in terms of position and force. Selecting the appropriate criteria for evaluating the ergonomics is essential to make a proper analysis of how the workplace affects the user and vice versa. On the other hand, the DHM software IPS-IMMA has been employed to simulate the exact postures adopted by the participants with a digital truck model and mannikins with the same dimensions. Both methods are compared to study to what degree they are able to give the necessary feedback to evaluate in a realistic and accurate way.The results obtained show an advantage for motion capture systems rather than DHM tools. However, by getting improvements in the software and new types of data to implement, we could be able to state that both technologies are near the same level of accuracy and proper application for a digital twin process in trucks and vehicles. We consider this methodology quite appropriate for companies with the purpose of making ergonomics analyses and other issues that relate to the design and development of trucks and vehicles. Also, different processes and types of digital twin approach have been realised depending on the tool employed and the flow of information, including digital twin itself, digital shadow and digital model. Although these processes have been realised to perform the experimental part in the most optimal way, they can be somewhat abstract to be established for a certain application,so the methodology employed for this project could vary for another company’s purpose.

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  • 1518.
    Niemi, Susanna
    University of Skövde, School of Informatics.
    Obehag i en neutral miljö: En studie i att påverka upplevelsen av en virtuell miljö som inte är typisk för skräckgenren2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Det här arbetet undersöker påverkan på känslan av obehag i en miljö som inte är typisk för skräckgenren. Arbetet är baserat på teorier från Sigmund Freuds (1919) The Uncanny, samt Therriens (2009) Games of Fear: A Multi-Faceted Historical Account of the Horror Genre in Video Games för ett mer modernare spelrelaterat perspektiv.

    Till undersökningen har en stadsmiljö i 3D-grafik skapats. Av stadsmiljön finns tre scener i olika versioner där obehagliga detaljer implementerats i form av blod och blodspår, tomhet från andra människor och mörker. Undersökningsmetoden som använts är kvalitativ med semistrukturerade intervjuer.

    Resultatet visar tendensen att blod och blodspårsdetaljerna upplevdes obehagliga, men att det var kombinationen av de olika obehagliga implementeringarna i scenerna som frammanade starkast känslor av obehag.

    I framtida arbete skulle stadsmiljön ha en mer detaljrik omgivning och använda sig av ett större urval av informanter i undersökningen. Detta för att se om tendensen stärks.

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  • 1519.
    Nikolakis, Nikolaos
    et al.
    Laboratory for Manufacturing Systems and Automation, Department of Mechanical Engineering and Aeronautics, University of Patras, Greece.
    Senington, Richard
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Sipsas, Konstantinos
    Laboratory for Manufacturing Systems and Automation, Department of Mechanical Engineering and Aeronautics, University of Patras, Greece.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Makris, Sotiris
    Laboratory for Manufacturing Systems and Automation, Department of Mechanical Engineering and Aeronautics, University of Patras, Greece.
    On a containerized approach for the dynamic planning and control of a cyber - physical production system2020In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 64, article id 101919Article in journal (Refereed)
    Abstract [en]

    The increased complexity of modern production systems requires sophisticated system control approaches to maintain high levels of flexibility. Furthermore, the request for customized production with the introduction of heterogeneous production resources, increases the diversity of manufacturing systems making their reconfiguration complex and time consuming. In this paper, an end-to-end approach for reconfigurable cyber-physical production systems is discussed, enabled by container technologies. The presented approach enhances flexibility in a cyber-physical production system (CPPS) through the dynamic reconfiguration of the automation system and the production schedule, based on occurring events. High-level management of manufacturing operations is performed on a centralized node while the data processing and execution control is handled at the network edge. Runtime events are generated at the edge and in smart connected devices via means of a variant of IEC61499 function blocks. Software containers manage the deployment and low-level orchestration of FBs at the edge devices. All aspects of the proposed solution have been implemented on a software framework and applied in a small scale CPPS coming from the automotive industry.

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  • 1520.
    Nilsson, Amanda
    et al.
    University of Skövde, School of Engineering Science.
    Lindqvist, Hanna
    University of Skövde, School of Engineering Science.
    Framtidens produktionspersonal i den Smarta fabriken2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The project has explored the topic Smart factory with main focus on the future production staff. The project aims to investigate how the production staff is affected by Volvo Cars Skövde Engine Plant (SkEP) becoming a Smart factory, in the era of Industry 4.0. The definition of the Smart factory is a demand of Mobile- and wireless technologies, Human-oriented, pursue a Flexible production with Sustainable manufacturing, as well as utilization of CPS (Cyber-Physical Systems), IoT (Internet-of-Things) and Cloud storage. The current situation and the future five to twenty years were examined in order to define the future production staff. This by conducting an observational study and several interviews. The studies’ results were that SkEP cannot be regarded as smart since several demands are inadequate by definition. Five years are considered too short of a time for the plant to fulfill the demands. However, according to the interviews and literature, SkEP are expected to become smart in twenty years after time refinement of existing technologies and implementation of new ones. The authors estimate Leadership, Information, IT and Production lay-out to be the areas that require the most effort. The future production staff are expected to be flexible with workplace, working hours and able to manage multiple variants. They should be included in self-supporting teams where every individual possesses an expertise, are motivated and participating. Production staff should perform complex, varied jobs with more responsibility by endorsement of decision support systems. The staffs’ competence should consist of technical education, high basic and lay-out knowledge and the ability to contribute to the collection of information and analyses. Interaction with technology is expected to expand and the personnel must therefore have a well-established comprehension of technology. The concept Smart factory is extensive and relatively new, which means that it is constantly evolving. Thus it is important for SkEP to be updated and adjust to the impact from the outside world.

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  • 1521.
    Nilsson, Bonny
    University of Skövde, School of Humanities and Informatics.
    Den Animerade Psykopaten: Och hur den uppfattas jämfört med sin icke-animerade motsvarighet2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I denna studie undersöks det ifall karaktärer med psykopatiskt beteende uppfattas mindre skrämmande och mer lättsamt i animerad form än i icke-animerad form. En litteraturstudie har genomförts som till stor del fokuserar på psykopater i film och de extrema personligheter och beteende som är frekventa i animerade verk. Två klipp har skapats utifrån två icke-animerade referensklipp innehållandes psykopatiska karaktärer spelade av skådespelare med identisk handling, karaktärsbeteende och miljö fast i animerad form. Dessa animerade klipp utvärderas genom strukturerade kvalitativa intervjuer med en fokusgrupp inriktad på föräldrar med barn som är 7-9 år gamla. Undersökningen visar att de animerade karaktärerna upplevs som mindre skrämmande och mer lättsamma än sina icke-animerade motsvarigheter.

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    Den Animerade Psykopaten
  • 1522.
    Nilsson, Jesper
    et al.
    University of Skövde, School of Engineering Science.
    Shamoun, Steven
    University of Skövde, School of Engineering Science.
    Decision Support for new Process Design via Discrete-event Simulation2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As a result of the technical breakthrough of modern age, manufacturing organisations are put through immense pressure to continually improve their internal processes with the purpose of economic growth in order to stay competitive in the global market. Thus, making trial and error obsolete in the real world systems, in relation to calculated decision making. This thesis aims to facilitate the decision making basis for the partner companies’ future production design by measuring its expected productivity with the purpose to further strengthen the collaboration with the customer, by the use of discrete-event simulation.AB Furhoffs Rostfria is a family-owned company with its base in Skövde that manufactures and pro-cesses stainless steel products and specialises in three central departments, plumbing, kitchen, and subcontracting products. This thesis focus is within the production of heat shields in the department of subcontracting products as they are projecting an annual increase of 20%.The project was initialised with a pre-study phase that includes the theoretical framework, covering all main subjects to be presented along with analysing relevant literature studies for valuable insight into previous studies within the same field. Following a method and execution phase was carried out coher-ently with creating a simulation model and data collection. Different scenarios in the simulation model have been presented to the partner company along with wastes that have been observed within the production flow during Gemba.The different scenarios in the simulation model included, for instance, the production of both bigger and smaller batch sizes for each variant to analyse how that factor correlates with the product lead time and to also find out what the most optimal batch sizes would be for the respective variant in order to build full pallets. The future state production was evaluated and the results reduced the mean lead time by roughly 59% compared to the current state production.

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  • 1523.
    Nilsson, Joacim
    University of Skövde, School of Informatics.
    Intranät som ett användbart stöd för informationsöverföring2014Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Intranät har stor potential att vara effektiva och interaktiva verktyg för informationsöverföring från ledningen ut till medarbetarna inom organisationer. Ett användbart intranät leder till att kommunikationen underlättas avsevärt, vilket betyder att medarbetarna blir mer produktiva och framgångsrika. Dessutom stärks lagandan och det är bra för företagskulturen som medför positiva bieffekter. I förlängningen blir då organisationen mer lönsam och vinner konkurrensfördelar gentemot sina rivaler. Hela samhället kan alltså dra nytta av det här i form av bland annat fler arbetstillfällen och ökade skatteintäkter. Diverse användbarhetsproblem innebär dock att den här idealiska bilden sällan blir verklighet. För att undersöka vilka orsaker som ligger till grund för att informationsöverföringen brister, där intranät har en nyckelroll i sammanhanget, behövs en djup och bred bild av de faktiska förhållandena som råder i kontexten - hur ledningen kommunicerar med de anställda via intranät. Den ansatsen har inneburit att undersökningen gestaltats i form av en heuristisk utvärdering och en enkät för att täcka både MDI-experters perspektiv såväl som användarnas upplevelse av fenomenet. Insamlad data triangulerades sedan för att berika analysen av upptäckterna. Resultatet av undersökningen medför en ökad förståelse för användbarhetsproblem som kan sätta käppar i hjulet för en fungerande informationsöverföring via intranät inom organisationer, men även konkreta förbättringsförslag och reflektioner kring hur intranät kan utformas för att möta framtidens krav lanseras.

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  • 1524.
    Nilsson, Jonatan
    University of Skövde, School of Engineering Science.
    Planering och utvecklande av testplattform för tryckpulsation2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Autotube is a company based in Varberg that develops and produces air- and fluid solutions primarily to the automotive industry. Recently the automotive manufacturers have increased the fuel injection pressure in petrol engines which has led to the absence of proper test equipment which limits the company’s product development department as pressure test has to be bought by a third-party company. The costs and lack of insight in the pressure tests that is associated with purchasing the service from a third part company has led Autotube to invest in new equipment that will allow the company to do future tests in-house. The ambition is to perform pressure pulsation tests and burst tests for both product development and production samples. The general purpose of the thesis is to program the PLC logic, design the HMI-panel and to create and electrically transferrable report after test completion.

    During the progression of the project studies and the company’s empirical knowledge showed that the result from a test facility is characterized primarily by three key parameters; functionality, real time monitoring and data management. Each category includes several subcategories that adds value to each key parameter.

    Functionality requires reliable hardware that can stay commissioned for extended periods of times without Interruption. However, if interruptions do occur it is important that the data from the ongoing test is saved so that data is not lost. To avoid irritation and mishandling it’s important to design the user interface according to the needs of the users and to avoid excessive information that is not vital for the result.

    A proper real time monitoring solution requires that information is easily available both at the location of the test facility and at distance in order to enable to user to act no matter where the user is located. Warning signals that indicate when the test facility does not perform as expected should be used in order to reduce the workload.

    Data management should be automatic in order to store the correct data and prevent errors caused by the human factor. Several reports should be used during the test as it allows the user to compare the data in the different test stages which improves the insight and analysis capability of the performed test.

    The performed work has analysed different alternatives and used literature relevant to the key parameters combined with continuous feedback from the company’s technicians in order to create the software for the test facility. The result is a reliable facility with tailored real time monitoring and automatic data management.

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  • 1525.
    Nilsson, Jonathan
    University of Skövde, School of Informatics.
    FÖRFLYTTNINGSEGENSKAPER ISTILISERADE RÖRELSER: En studie om generaliserbaraanimationskurvor2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
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    FÖRFLYTTNINGSEGENSKAPER ISTILISERADE RÖRELSER
  • 1526.
    Nilsson, Maria
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Characterising User Interaction to Inform Information-Fusion-Driven Decision Support2008In: Proceedings of the ECCE 2008: European Conference on Cognitive Ergonomics: The Ergonomics of cool interaction / [ed] Julio Abascal; Inmaculada Fajardo; Ian Oakley, ACM Press, 2008, p. 10-13, article id 3Conference paper (Refereed)
    Abstract [en]

    Motivation – The motivation is to extend the current technology driven design approach in information fusion by characterising how users interact with and are active components in information fusion based decision support.

    Research approach – A combination of theoretical and empirical investigations has been chosen to examine how users interact with information fusion based decision support.

    Findings/Design – The results define the building blocks for a future framework. So far, a new decision support class, i.e., fusion driven decision support, has been suggested. The class characterises the information fusion process, the users’ role, and factors that affect interactions with such systems. Also, the result indicates that Distributed Cognition is a useful tool for capturing semi-automated information fusion processes.

    Research limitations/Implications – So far, the building blocks for a framework, which capture users and information fusion systems, have been identified and further studies are needed in order to fully develop the framework.

    Originality/Value – The characterisation of the user makes a contribution to the technologically oriented research field of information fusion, which most often considers users as passive receivers of information. In addition, the research makes a contribution to the field of decision support by extending the current list of decision support classes with semi-automated decision support.

    Take away message – Unlike common beliefs, the information fusion process extends the boundary of the physical system, to include humans, technology, tools and the interactions among them.

  • 1527.
    Nilsson, Maria
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Rethinking HCI for information fusion and decision support2006In: Proceedings of the 20th BCS HCI Group Conference in co-operation with ACM: HCI 2006, Queen Mary University of London, 11-15 September 2006: Engage / [ed] Bob Fields, Tony Stockman, Louise Valgerður Nickerson, Patrick G. T. Healey, London: Queen Mary University of London , 2006, Vol. 2, p. 225-227Conference paper (Refereed)
    Abstract [en]

    The focus of information fusion has traditionally been on the technical aspects e.g. algorithms. However, the importance of also understanding human information processing is gaining increasing recognition. The research outlined here aims to incorporate and widen the perspective of HCI in information fusion and decision support research i.e. the utilisation of the user as an active component in the information fusion process. A new perspective of the information fusion process is proposed and distributed cognition is identified as a theoretical framework capturing the process. Also, initial results indicate that trust, uncertainty and temporal aspects are issues affecting the interaction between the user and the information fusion system. © BCS HCI Group Conference: Engage, HCI 2006.All right reserved.

  • 1528.
    Nilsson, Morgan
    University of Skövde, School of Informatics. morgannilsson81@gmail.com.
    Morgondagens handel: Smartmobilen länken till en sömlös upplevelse2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Konkurrensen inom detaljhandeln har blivit allt tuffare sedan internets uppkomst vilket har lett till att kunders beteende har börjat förändrats, samtidigt som upplevelsen både på internet och iden fysiska butiken har hamnat alltmer i fokus. En bra användarupplevelse och kundupplevelseär idag en av de viktigaste konkurrensfördelarna ett företag kan ha inom detaljhandeln. Forskning inom detaljhandeln har visat att kunder idag efterfrågar bättre personliga upplevelser vid rätt tidpunkt och plats, vilket smartmobilen potentiellt skulle kunna uppfylla i den fysiskabutiken. Studiens syfte är således att undersöka om upplevelsen i den fysiska butiken potentiellt skulle kunna förbättras av dagens smartmobiler, studien har avgränsats till kläd- och skobutiker. Genom att besvara problemformuleringen kan studien inte endast förhoppningsvis hjälpa dagens fysiska butiker att potentiellt förbättra upplevelsen för sin kunder utan även ge forskningen nya insikter om hur den digital och fysiska världen kan sammanföras i ett. Resultatet av examensarbetet indikerar att smartmobilen kan förbättra upplevelsen för kunden genom attsammanväva den personliga informationen från internet med den fysiska butikens sortiment och layout.

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  • 1529.
    Nilsson, P. O.
    et al.
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Karlsson, Krister
    Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Rundgren, J.
    Department of Theoretical Physics, Royal Institute of Technology, Stockholm, Sweden.
    Prediction of image-state excitation by secondary beams in inverse-photoemission spectroscopy1993In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 47, no 19, p. 12968-12971Article in journal (Refereed)
    Abstract [en]

    Excitation of image states is predicted to occur frequently in inverse-photoemission spectroscopy due to diffracted electron beams traveling almost parallel to the surface. A simple kinematic model, as well as full calculations using inverse low-energy electron-diffraction theory, show the effect in the case of Cd(0001).

  • 1530.
    Nilsson, Pernilla
    et al.
    Högskolan i Halmstad.
    Johansson, Hans
    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.
    Arén, Björn
    Örebro universitet.
    Söderström, Eva
    University of Skövde, School of Humanities and Informatics.
    Chibba, Aron
    Högskolan i Halmstad.
    Distribuerad case-metodik i ingenjörsutbildningen2009In: Den 2:a Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Lunds Tekniska Högskola, Genombrottet , 2009, p. 71-73Conference paper (Other academic)
    Abstract [en]

    This paper is based on a project in which an academic developer worked as a critical friend for a group of engineering in order to stimulate their collaboration and their reflection on their own teaching and learning as a way of developing their scholarship of teaching. The project was built on collaboration between three different universities, Halmstad, Örebro and Skövde and reports on how teachers, as well as the students collaborative learning experiences.

  • 1531.
    Nilsson, Rasmus
    et al.
    University of Skövde, School of Engineering Science.
    Persson, Andreas
    University of Skövde, School of Engineering Science.
    Automatiserings- och förbättringsförslag av paketeringsprocess2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Rekordverken is a company that specializes in producing bait spreader solutions for combine harvesters. The company's knife production is about to undergo major changes. In connection with this, Rekordverken wants to automate the packaging process of their knives. The knives come to the packaging in cassettes containing 120–200 knives each depending on the model. About 60% of the knives are packaged in ten packs and the remaining 40% are packaged in fifty packs. The company wants a working area with an automated cell without robot that uses compressed air and / or linear units instead. Some elements will still be performed by an operator, so a new layout of the work area with focus on ergonomics, availability and stock levels needs to be designed.

    The first step was to visit the company on a number of occasions to form an idea of the current state, that is, the design, working methods and the flow of products and transport. All of the above was documented through notes, drawings and pictures. Once the desired information was collected, it was analyzed to identify where the greatest focus for improvement should be. An automated cell is part of the intended future layout and a well thought out proposal would be designed and presented. The cell would then be realized in a simple 3D model and theoretically explained. With the data collected as the basis, the most suitable location of the cell was chosen.

    In the proposed proposal, the dimensions of the packaging area are unchanged, and the new design has some similarities to the current one. The placement of pallets with packaging is retained and the same applies to the placement of empty cassettes and used packaging belonging to pallets with knife cassettes. The operator station has been moved and slightly reduced to accommodate the automation cell, and the same applies to the two pallet lifts.

    The record works are considered to benefit from the proposed proposal. By implementing a new design of the packaging area (including an automated cell), they create a packaging process that is in line with the changes to automation planned in the rest of the production. Industrial technology is developing rapidly and by switching to an automated system it now opens up for more improvements in the future.

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  • 1532.
    Nilsson, Robert
    et al.
    University of Skövde, School of Humanities and Informatics.
    Henriksson, Dan
    Department of Automatic Control, Lund University, Lund, Sweden.
    Test Case Generation for Flexible Real-Time Control Systems2005In: 10th IEEE international conference of Emerging Technologies and Factory Automation: ETFA 2005 / [ed] L. LoBello; T. Sauter, IEEE conference proceedings, 2005, p. 723-730Conference paper (Refereed)
    Abstract [en]

    Temporal correctness is crucial for the dependability of real-time control systems. A problem with testing such systems is the dependency on the execution orders of tasks. Mutation-based testing criteria have been proposed to determine which execution orders need to be exercised to verify that real-time systems are timely. For flexible control systems, timeliness in itself may only be relevant for a subset of tasks, whereas maintained control performance in the presence of worst-case jitter and disturbances is essential. This paper presents an extension to the co-simulator tool TrueTime, to support mutation-based testing of control performance and timeliness. Further, an approach for automatic generation of test cases using genetic algorithms is presented. A conclusion is that testing criteria for timeliness can be used to increase confidence in the dependability of flexible control systems.

  • 1533.
    Nilsson, Robert
    et al.
    University of Skövde, School of Humanities and Informatics.
    Offutt, Jeff
    Information and Software Engineering, George Mason University, Fairfax Virginia, USA.
    Mellin, Jonas
    University of Skövde, School of Humanities and Informatics.
    Test case generation for mutation-based testing of timeliness2006In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 164, no 4, p. 97-114Article in journal (Refereed)
    Abstract [en]

    Temporal correctness is crucial for real-time systems. Few methods exist to test temporal correctness and most methods used in practice are ad-hoc. A problem with testing real-time applications is the response-time dependency on the execution order of concurrent tasks. Execution order in turn depends on execution environment properties such as scheduling protocols, use of mutual exclusive resources as well as the point in time when stimuli is injected. Model based mutation testing has previously been proposed to determine the execution orders that need to be verified to increase confidence in timeliness. An effective way to automatically generate such test cases for dynamic real-time systems is still needed. This paper presents a method using heuristic-driven simulation to generate test cases.

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  • 1534.
    Nilsson, Robin
    University of Skövde, School of Informatics.
    Efterlevnad av den enskildes rättigheter enligt Dataskyddsförordningen GDPR: En fallstudie om hur en organisation har påverkats av den enskildes rättigheter, samt vilka åtgärder som vidtas för efterlevnad2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The General Data Protection Regulation (GDPR) became mandatory on 25 May 2018 for all organizations within Europe who collect and process personal data. The General Data Protection Regulation replaced the Personal Data Act, which previously was the law that regulated in Sweden how organizations may process personal data.

    A central part of the GDPR is the individual's rights which consist of 8 rights and describe what rights an individual has when an organization processes their personal data. Much of what previously applied in the Personal Data Act has been expanded through the individual's rights and thus organizations that process personal data have had to change their organization to meet the new requirements.

    The purpose of this thesis is to sort out in what ways the individual's rights have affected an organization in order to comply with the new requirements. By the use of a literature study, research has been identified that was published prior to the GDPR became mandatory which analyzes and describes how organizations should be affected by the data protection ordinance.

    With the help of a qualitative method, interviews were conducted via a case study to find out what actual impact the individual's rights lead to in the form of which adjustments the organization needed to make in order to be considered in phase with the legal requirements. The result of the interviews was analyzed and compared with the previously identified research to be able to draw conclusions about the actual impact of the new rights.

    The result shows in what ways the individual's rights have affected the organization in the form of new administrative processes, routines and technical functionality in order to meet the requirements that the individual's rights require.

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  • 1535.
    Nilsson, Stefan
    University of Skövde, School of Informatics.
    Vägplanering med slumpmässig genusfördelning i genetiska algoritmer2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Den här studien beskriver en undersökning som tittar på prestationsskillnaden på engenetisk algoritm (GA) med kön, mot en GA utan kön. Den tittar även påprestationsskillnaden mellan en GA utan kön och en GA med slumpmässig könsfördelning.Problemet som algoritmerna är applicerade på innefattar vägplanering över en kontinuerlig,procedurell 2d-miljö som är uppbyggd av polygoner med olika färdkostnad. Den lämpligasteindividen blir den med lägst färdkostnad, som alltså hittar den billigaste vägen mellan tvåfasta punkter. Observera att problemet är fullständigt statiskt genom alla körningar.Utfallet tyder på att GA’n med kön producerar märkbart bättre resultat, oavsett omkönsdistribueringen var konstant eller slumpmässig. De genetiska algoritmerna med könuppvisade också en mindre tendens att konvergera, vilket tyder på att införandet av kön ialgoritmen hade den hypotiserade effekten. Införandet av slumpmässig könsfördelning tycksha resulterat i en mer konstant diversitet.Vidare arbete skulle kunna innefatta en jämförelse mellan genetiska algoritmer med ochutan kön för fler typer av problem. Detta skulle kunna leda till en allmän teori somsammanfattar könets påverkan på de genetiska algoritmerna allmänt. Vidare studier skulleäven kunna titta på hur kön påverkar diversiteten i algoritmen, genom att göra sammajämförelser, men istället titta på hur den genetiska diversiteten utvecklas över tid.

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  • 1536.
    Nohlberg, Marcus
    et al.
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Johannes, Bäckström
    Department of Computer and Information Science, University of Linköping, Linköping, Sweden.
    User-centered security applied to the development of a management information system2007In: Information Management & Computer Security, ISSN 0968-5227, E-ISSN 1758-5805, Vol. 15, no 5, p. 372-381Article in journal (Refereed)
    Abstract [en]

    Purpose – This paper aims to use user-centred security development of a prototype graphical interface for a management information system dealing with information security with upper-level management as the intended users.

    Design/methodology/approach – The intended users were studied in order to understand their needs. An iterative design process was used where the designs were first made on paper, then as a prototype interface and later as a final interface design. All was tested by subjects within the target user group.

    Findings – The interface was perceived as being successful by the test subjects and the sponsoring organization, Siguru. The major conclusion of the study is that managers use knowledge of information security mainly for financial and strategic matters which focus more on risk issues than security issues. To facilitate the need of managers the study presents three heuristics for the design of management information security system interfaces.

    Research limitations/implications – This interface was tested on a limited set of users and further tests could be done, especially of users with other cultural/professional backgrounds.

    Practical implications – This paper presents a useful set of heuristics that can be used in development of management information systems as well as other practical tips for similar projects.

    Originality/value – This paper gives an example of a successful user-centred security development process. The lessons learned could be beneficial in software development in general and security products in particular.

  • 1537.
    Nord, Jens
    et al.
    University of Skövde, School of Technology and Society.
    Johansson, Peter
    University of Skövde, School of Technology and Society.
    Vägen till Lean Production: Historien bakom Lean och dess nutida användning2007Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are many important challenges for industry of today, and efficient manufacturing is one of them. To manage some of these challenges many businesses put a lot of faith in the management philosophy called Lean Production. The first objective of this report is to find out how three different Swedish companies have worked with the complex toolbox of Lean production and how they have implemented these tools. The second objective of this report is to analyze possible similarities between the implementations of Lean and the fourteen management principles of efficient manufacturing according to Toyota.

    In 1911 Fredrick Winslow Taylor published an article, “Principles of Scientific Management”, on how to make industry more efficient. Henry Ford, the father of modern cars, accepted Taylor’s ideas and applied them in his new car factory in Detroit in 1912. Taylor’s fundamental ideas together with Ford’s enterprising attitude and the modern assembly line led to large sales success of the T-Ford. Some decades later the Japanese car manufacturer Toyota interested themselves in the American management of making cars due to financial difficulties. In 1950 Toyota started the process of developing their own production management system, Toyota Production System. The Japanese production system was successful and lifted Toyota out of the financial crisis. The 1973 oil crisis limited the sales of big American cars in favour of smaller and cheaper Japanese ones. The American car makers paid attention and financed a research project at Massachusetts Institute of Technology in order to develop an even better production system, Lean Production.

    The three case studies, two factories of AstraZeneca in Södertälje and a Volvo Powertrain factory in Skövde have developed different strategies in implementing Lean Production. The empirical studies are based on personal interviews with people understanding the development work in each organisation. The first AstraZeneca factory shows a noncommittal approach where the employees take a great part in the decision-making process. The second AstraZeneca factory shows a more strict approach where the result-orientated tools are in the centre of interest. The Volvo Powertrain factory has gained experience from this kind of development work through the past twenty years. They have had both the time and knowledge to implement a wide range of tools and methods.

    To make the Lean projects permanent and a way of life rather than just a set of tools it is important for organisations to implement both the human relation approach and the structural tool-oriented approach. The human relation approach focuses on the employees, their self-esteem and their right to be a part of the decision-making. The core of the structural approach is the result oriented tools and methods. The case studies clearly show that the fourteen principles of Toyota Production System represent a holistic view on logistics development. If some of the principles are not represented in a project there is a big risk that the project will fail. Resilience is the key word to increase the chance of being Lean.

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  • 1538.
    Nordberg, Pontus
    University of Skövde, School of Informatics.
    CHALLENGES IN SECURITY AUDITS IN OPEN SOURCE SYSTEMS2019Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Today there is a heavy integration of information technology in almost every aspect of our lives and there is an increase in computer security that goes with it. To ensure this security, and that policies and procedures within an organisations related to this security are enforced; security audits are conducted.

    At the same time, use of open source software is also becoming increasingly common, becoming more a fact of life rather than an option. With these two trends in mind, this study analyses a selection of scientific literature on the topic and identifies the unique challenges a security audit in an open source environment faces, and aims to contribute on how to help alleviate the challenges.

    The study was performed in the form of a literature review, where the comparison and analysis revealed interesting information regarding the open source specific challenges, including both technical issues as well as challenges stemming from people’s perception and handling of open source software today.

    The answer to the question “What are the challenges when conducting security audits for open source systems and how can they be alleviated?” shows the main challenges to be too much trust is put in unverified binaries. The report offers suggestions and ideas on how to implement solutions in order to help diminish this challenge through the use and integration of Reproducible Builds, answering the second part of the question.

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  • 1539.
    Nordby, Johan
    et al.
    University of Skövde, School of Engineering Science.
    Tholin, Mikael
    University of Skövde, School of Engineering Science.
    TIDSSTUDIEANALYS AV MANUELL PRODUKTHANTERING VID I- OCH URLASTNING I PRODUKTIONSUTRUSTNINGAR: Produktionssystemutveckling enligt Chaku-Chaku/Hanedashi-principen2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The project is located at Autoliv Sverige AB (Autoliv) in Vårgårda. Autoliv wants to improve the handle of material in the processes by increasing the availability of the machines. Material is alternately handled by man and machine. The mission is to make one or more concrete that uses the production technique Chaku-Chaku, also known as Hanedashi, as well as being a solution efficient regarding both cost and time and to make use of already existing production equipment.The project is narrowed to just include the top three production cells that demands the most production (operator) time as well as one newly created cell.To be able to calculate the time efficiency on the processes we made a time study and with the analysis of the study we could determine important values of the production for later savings calculations. Four suggestions of improvements were developed and analyzed for time efficiency. Three out of these four were handpicked to be calculated for cost and cost savings of the maximum capacity of the new production or if the yearly production stayed the same. The requirement was that the new maximized production would increase the yearly production by 7%.The first of the handpicked suggestions was to preassemble a component on a separate table instead of assemble it inside of a machine, for this was regarded as a problematic procedure. The solution also contained a new schedule of movements for the operators and a new production cell layout. The second suggestion of improvement aim that when the module has been in one of the assembly machines it will automatically be ejected and therefor made available for the next module. The first and second solutions are recommended to be combined as these can be a complement for each other, as these suggestions are on the same production cell. The third solution was to implement a grasping device that moved aside the module a bit to be processed manually. Thus would make it possible for the next module to be placed inside the machine at the same time. This solution would make two separate waiting times into one synchronized processing. The suggestions of improvements were calculated to result in saved labour if production stayed the same. If the production were maximized the calculations showed the point of break-even. The suggestions would pay-off after 700 units were manufactured on each production cell and further increase the capacity with more than 7%.

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  • 1540.
    Nordqvist, Malin
    University of Skövde, School of Informatics.
    Operatörens upplevelse av tillit vid samarbete med en kollaborativ robot2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med arbetet är att undersöka omfattningen av tillit som en operatör upplever vid samarbete med en kollaborativ robot. Tidigare forskning inom människa-robotinteraktion och människa-robotkollaboration visar på att det inte är tillräckligt att utvärdera säkerhet för att förbigå olycksfall mellan operatörer och robotar. När den fjärde industrirevolutionen inkorporeras i tillverkningsindustrin och kollaborativa robotar och operatörer ska arbeta i symbios med varandra utan säkerhetsgrindar och galler, kommer aspekten av säkerhet och tillit inom människa-robotkollaboration vara än viktigare att utvärdera. Genom litteraturstudien i detta arbete identifierades att det inte fanns en strukturerad utvärderingsmetod eller teknik för att utvärdera en operatörs upplevelse av tillit. Insikten resulterade i en vidareutveckling av ramverket USUS-goals till USUS-Tillit. Genom att använda ramverket USUS-Tillit som utvärderingsmetod har omfattningen av tillit kunnat utvärderas genom dels en heuristiks utvärdering och UX-testning där flera testdeltagare har genomfört ett scenario med en röststyrd kollaborativ robot. Scenariot handlade om att tillsammans med roboten bygga ihop en enklare leksaksbil där testdeltagaren och roboten genomförde arbetsmoment var och en för sig, men även tillsammans. Resultatet av testningen visade på att testdeltagarna upplevde begränsad tillit under samarbetet med roboten, något som bland annat kunde kopplas ihop med osäkerhet till sin egen förmåga, där osäkerheten var starkt sammankopplad till robotens avancerade interaktionsparadigm. Industrin är en viktig motor för Sveriges välfärd och eftersom industri 4.0 kommer innebära nära samarbete mellan robotar och operatörer, kommer operatörens upplevelse av interaktionen med roboten bli viktigare. Att utvärdera operatörers upplevelse av tillit kan vara en pusselbit som saknats när det kommer till att kunna garantera säkerheten för operatörerna i industrin. UX kompetensen kommer därför vara starkt efterfrågad i industridomänen i framtiden då UX uteslutande fokuserar på en användares (operatörens) upplevelse.

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  • 1541.
    Nordqvist, Malin
    et al.
    University of Skövde, School of Informatics.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Operators' Experience of Trust in Manual Assembly with a Collaborative Robot2018In: HAI '18 Proceedings of the 6th International Conference on Human-Agent Interaction / [ed] Michita Imai, Tim Norman, Elizabeth Sklar, Takanori Komatsu, New York, NY, USA: ACM Digital Library, 2018, p. 341-343Conference paper (Refereed)
    Abstract [en]

    Advancements in human-robot collaboration (HRC) are major aspects of the future Industry 4.0. HRC entails humans that cooperatively work with fenceless robots in dynamic, changing, and rather unpredictable settings where they should assist and learn from each other and automatically respond to changes [1]. The envisioning of smart factories of the future results in new and additional challenges for how to evaluate various aspects of the collaboration between the human operator and the robot. The common practice in HRC is to focus on safety and performance-related issues, which are highly influenced by human factors (HF). Because of the prevailing orientation towards HF, HRC runs the risk of not considering the modern understandings of human cognition and technology-mediated activity in a socio-material context [2]. Previous research reveals that safety is a necessary but not sufficient condition for avoiding accidents between humans and robots.

  • 1542.
    Nordström, John
    University of Skövde, School of Engineering Science.
    Riskbedömning av Cobot och integrering av verktyg2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The degree project concerns machine safety and risk assessment on a collaborative robot application. The goal is to perform a risk assessment using CEDOC which is a risk assessment program. The studies have contributed to three safety aspects that should be considered when implementing collaborative robots based on the machine safety perspective.

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  • 1543.
    Nordén Hermansson, Erik
    et al.
    University of Skövde, School of Engineering Science.
    Davidsson, Filip
    University of Skövde, School of Engineering Science.
    Utveckling av fallplåt: för en maskingradsax2014Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    To cut sheet metal into proper dimensions, for example shears can be used. They are available in many different variations where one is the guillotine shear. Rapido, manufactured by CIDAN Machinery, is a guillotine shear mainly targeted for small businesses which doesn´t cut regularly and with large size variations. This requires all manual material management which is stressful for the operator. The customers prefer the sheet metal to be available to be collected directly after the cut and at the same side of the machine as the input table. That’s why the sheet metal slides down on a plate called the sheet metal collector, located underneath the input table, in the current design. Because the input table has an ergonomic level of 85 cm, the sheet metal is collected from a much lower and uncomfortable level of 9 cm above the ground. The company wishes to approve the situation for the operator by offering an alternative sheet metal collector that makes the sheet metal available at higher level. The new solution shouldn´t raise the manufacturing cost more than 8%, to be profitable.

    A literature study is made to investigate solutions to similar problems and safety requirements. Concepts are generated and evaluated in an objective manner, for example by brainstorming and a concept selection matrix. One of the concepts is chosen for further development and design where standard components are top priority e.g. because of the reduction in environmental impact. Although standard components can´t solve for all functions and thus are unique parts designed. Some calculations are done analytically and by using the finite element method to verify the strength of the unique parts.

    In the resulting solution the operator can collect the sheet metal 37 cm above ground level and from a better position closer to the human body. The solution requires 15 new parts, of which 8 are standard components, and small modifications of 10 parts already in use. The increase of manufacturing cost is approximately 6 %. Pneumatics is used to lift the sheet metal which the operator only needs to activate, but the control function is not developed within the project.

    Even though the resulting solution doesn´t reach an ideal collecting height, of 80-110 cm, the company´s requirements is yet fulfilled. An additional function for ejecting the sheet metal is found to improve the ergonomics and is therefore included in the objectives for the project. Such function is included in the concept phase, but it isn´t further developed because of time constraints.

    Further investigations of CE-requirements need to be made before releasing the improved machine on the market since all necessary documents wasn´t available. More suggests of improvements is presented to the company, for example should silencing materials be used on the collector to reduce unpleasant noise.

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    Utveckling av fallplåt
  • 1544.
    Noremalm, Tobias
    et al.
    University of Skövde, School of Technology and Society.
    Bodén, Joakim
    University of Skövde, School of Technology and Society.
    Utveckling av skivspelare som påverkas minimalt av inre och yttre störningar2012Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The examination project was carried out in collaboration with Transient Design which is a company in the HiFi industry. The thesis project describes the development of a turntable. The project had the objective to propose a design concept as well as to propose relevant technical solutions.The work began with a pilot study which aimed to be a foundation upon which the rest of the project was built. The two big sections of this stage were the market research which aimed to create a better picture of the intended target group and also literature studies. The literature studies covered subjects such as vibration theory and technical measuring equipments. When a good foundation for the project had been established the idea generation phase commenced. During this phase a large amount of different concepts for the design as well as technical solutions were created. Through several selection processes with further development in between, three concepts emerged as viable solutions. From one of these the final concept, “Walter”, was deducted. Walter was named after the founder of the Bauhaus school in Germany. This seemed appropriate since a lot of design inspiration was gathered from the Bauhaus way.The development process resulted in Walter, a very cleanly designed turntable that hides many technical developments including solutions for slide bearing construction and platter construction.

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    Utveckling av skivspelare som påverkas minimalt av inre och yttre störningar
  • 1545.
    Nourmohammadi, Amir
    et al.
    Faculty of Industrial & Systems Engineering, Tarbiat Modares University, Tehran, Iran.
    Eskandari, Hamidreza
    Iran Management & Technology Development Center, Tarbiat Modares University, Tehran, Iran.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Design of stochastic assembly lines considering line balancing and part feeding with supermarkets2019In: Engineering optimization (Print), ISSN 0305-215X, E-ISSN 1029-0273, Vol. 51, no 1, p. 63-83Article in journal (Refereed)
    Abstract [en]

    This article aims to address the assembly line balancing problem (ALBP) and supermarket location problem (SLP) as two long-term interrelated decision problems considering the stochastic nature of the task times and demands. These problems arise in real-world assembly lines during the strategic decision-making phase of configuring new assembly lines from both line balancing and part-feeding (PF) aspects. A hierarchical mathematical programming model is developed, in which the first level resolves the stochastic ALBP by minimizing the workstation numbers and the second level deals with the stochastic SLP while optimizing the PF shipment, inventory and installation costs. The results of case data from an automotive parts manufacturer and a set of standard test problems verified that the proposed model can optimize the configuration of assembly lines considering both ALBP and SLP performance measures. This study also validates the effect of the stochastic ALBP on the resulting SLP solutions.

  • 1546.
    Nourmohammadi, Amir
    et al.
    Tarbiat Modares University, Tehran, Iran.
    Eskandari, Hamidreza
    Tarbiat Modares University, Tehran, Iran.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Aghdasi, Mohammad
    Tarbiat Modares University, Tehran, Iran.
    A mathematical model for supermarket location problem with stochastic station demands2018In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 72, p. 6p. 444-449Article in journal (Refereed)
    Abstract [en]

    This paper aims to investigate the effect of station demands variations on supermarket location problem (SLP). This problem arises in the real-world assembly line part feeding (PF) context where supermarkets are used as the intermediate storage areas for stations. To this purpose a stochastic SLP model is developed to optimize the total cost of PF in terms of shipment, inventory and installation costs. The computational results over a real case as well as different test instances verify that the station demands variation has an effect on the SLP solutions.

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  • 1547.
    Nourmohammadi, Amir
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Faculty of Industrial & Systems Engineering, Tarbiat Modares University, Tehran, Iran.
    Eskandari, Hamidreza
    Faculty of Management and Economics, Tarbiat Modares University, Tehran, Iran / School of Management, Swansea University, UK.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos H. C.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Integrated locating in-house logistics areas and transport vehicles selection problem in assembly lines2021In: International Journal of Production Research, ISSN 0020-7543, E-ISSN 1366-588X, Vol. 59, no 2, p. 598-616Article in journal (Refereed)
    Abstract [en]

    Decentralised in-house logistics areas, known as supermarkets, are widely used in the manufacturing industry for parts feeding to assembly lines. In contrary to the literature and inspired by observation in a real case, this study relaxes the assumption of using identical transport vehicles when deciding on the supermarkets’ location by considering the availability of different vehicles. In this regard, this study deals with the integrated supermarket location and transport vehicles selection problems (SLTVSP). A mixed-integer programming (MIP) model of the problem is developed. Due to the complexity of the problem, a hybrid genetic algorithm (GA) with variable neighborhood search (GA-VNS) is also proposed to address large-sized problems. The performance of GA-VNS is compared against the MIP, the basic GA, and simulated annealing (SA) algorithm. The computational results from the real case and a set of generated test problems show that GA-VNS provides a very good approximation of the MIP solutions at a much shorter computational time while outperforming the other compared algorithms. The analysis of the results reveals that it is beneficial to apply different transport vehicles rather than identical vehicles for SLTVSP.

  • 1548.
    Nourmohammadi, Amir
    et al.
    Tarbiat Modares University, Tehran, Iran.
    Eskandari, Hamidreza
    Tarbiat Modares University, Tehran, Iran.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ranjbar Bourani, Mehdi
    University of Science & Technology of Mazandaran, Behshahr, Iran.
    An integrated model for cost-oriented assembly line balancing and parts feeding with supermarkets2018In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 72, p. 5p. 381-385Article in journal (Refereed)
    Abstract [en]

    This paper aims to deal with assembly line design from both line balancing and parts feeding (PF) aspects as two-interrelated decision problems while supermarkets are used. These problems arise in the real-world assembly lines (ALs) where decision makers are planning to simultaneously determine the optimal number of stations and the optimal number of supermarkets so that the total installation costs of ALs including line balancing and PF costs are minimized. To this purpose an integrated mathematical model is proposed and its performance is tested through solving a number of benchmark problems and a real case taken from industry.

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  • 1549.
    Nourmohammadi, Amir
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment. Division of Industrial Engineering and Management, Uppsala University, Sweden.
    Ng, Amos H. C.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment. Division of Industrial Engineering and Management, Uppsala University, Sweden.
    Balancing and scheduling assembly lines with human-robot collaboration tasks2022In: Computers & Operations Research, ISSN 0305-0548, E-ISSN 1873-765X, Vol. 140, p. 1-18, article id 105674Article in journal (Refereed)
    Abstract [en]

    In light of the Industry 5.0 trend towards human-centric and resilient industries, human-robot collaboration (HRC) assembly lines can be used to enhance productivity and workers’ well-being, provided that the optimal allocation of tasks and available resources can be determined. This study investigates the assembly line balancing problem (ALBP), considering HRC. This problem, abbreviated ALBP-HRC, arises in advanced manufacturing systems, where humans and collaborative robots share the same workplace and can simultaneously perform tasks in parallel or in collaboration. Driven by the need to solve the more complex assembly line-balancing problems found in the automotive industry, this study aims to address the ALBP-HRC with the cycle time and the number of operators (humans and robots) as the primary and secondary objective, respectively. In addition to the traditional ALBP constraints, the human and robot characteristics, in terms of task times, allowing multiple humans and robots at stations, and their joint/collaborative tasks are formulated into a new mixed-integer linear programming (MILP) model. A neighborhood-search simulated annealing (SA) is proposed with customized solution representation and neighborhood search operators designed to fit into the problem characteristics. Furthermore, the proposed SA features an adaptive neighborhood selection mechanism that enables the SA to utilize its exploration history to dynamically choose appropriate neighborhood operators as the search evolves. The proposed MILP and SA are implemented on real cases taken from the automotive industry where stations are designed for HRC. The computational results over different problems show that the adaptive SA produces promising solutions compared to the MILP and other swarm intelligence algorithms, namely genetic algorithm, particle swarm optimization, and artificial bee colony. The comparisons of human/robot versus HRC settings in the case study indicate significant improvement in the productivity of the assembly line when multiple humans and robots with collaborative tasks are permissible at stations.

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  • 1550.
    Nourmohammadi, Amir
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment. Division of Industrial Engineering and Management, Uppsala University, Sweden.
    Ng, Amos H. C.
    University of Skövde, School of Engineering Science. University of Skövde, Virtual Engineering Research Environment. Division of Industrial Engineering and Management, Uppsala University, Sweden.
    Balancing and scheduling human-robot collaborated assembly lines with layout and objective consideration2024In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 187, article id 109775Article in journal (Refereed)
    Abstract [en]

    The recent Industry 4.0 trend, followed by the technological advancement of collaborative robots, has urged many industries to shift towards new types of assembly lines with human-robot collaboration (HRC). This type of manufacturing line, in which human skill is supported by robot agility, demands an integrated balancing and scheduling of tasks and operators among the stations. This study attempts to deal with these joint problems in the straight and U-shaped assembly lines while considering different objectives, namely, the number of stations (Type-1), the cycle time (Type-2), and the cost of stations, operators, and robot energy consumption (Type-rw). The latter type often arises in the real world, where multiple types of humans and robots with different skills and energy levels can perform the assembly tasks collaboratively or in parallel at stations. Additionally, practical constraints, namely robot tool changes, zoning, and technological requirements, are considered in Type-rw. Accordingly, different mixed-integer linear programming (MILP) models for straight and U-shaped layouts are proposed with efficient lower and upper bounds for each objective. The computational results validate the efficiency of the proposed MILP model with bounded objectives while addressing an application case and different test problem sizes. In addition, the analysis of results shows that the U-shaped layout offers greater flexibility than the straight line, leading to more efficient solutions for JIT production, particularly in objective Type-2 followed by Type-rw and Type-1. Moreover, the U-shaped lines featuring a high HRC level can further enhance the achievement of desired objectives compared to the straight lines with no or limited HRC.

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