his.sePublications
Change search
Refine search result
45678910 301 - 350 of 633
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 301.
    Islam, M. S.
    et al.
    Department of Mechanical Engineering, Blekinge Institute of Technology, Karlskrona, Sweden.
    Alfredsson, K. Svante
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Peeling of metal foil from a compliant substrate2019In: The journal of adhesion, ISSN 0021-8464, E-ISSN 1563-518XArticle in journal (Refereed)
    Abstract [en]

    Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used as input data to the resulting analytical beam model. Test results from the literature were analysed. A more elaborate finite element model was also studied, using cohesive elements for the interface layer between the foil and the substrate. The cohesive zone parameters used were the fracture energy, the cohesive strength and a shape parameter. An optimization scheme for the cohesive zone parameters was developed and optimized against experimental steady-state peel force and root rotation. The optimization scheme was effective to characterize the cohesive parameters. The method yields similar values of fracture energy for the two peel angles, with the one for being slightly higher than for . The difference in fracture energies for different peel angles suggests that the fracture energy can be mode dependent.

  • 302.
    Izquierdo, Milagros
    et al.
    Department of Mathematics, Linköping University, Linköping, Sweden.
    Stokes, Klara
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Isometric point-circle configurations on surfaces from uniform maps2016In: Symmetries in Graphs, Maps, and Polytopes: 5th SIGMAP Workshop, West Malvern, UK, July 2014 / [ed] Jozef Širáň, Robert Jajcay, Springer, 2016, p. 201-212Chapter in book (Refereed)
    Abstract [en]

    We embed neighborhood geometries of graphs on surfaces as point-circle configurations. We give examples coming from regular maps on surfaces with a maximum number of automorphisms for their genus, and survey geometric realization of pentagonal geometries coming from Moore graphs. An infinite family of point-circle v4 configurations on p-gonal surfaces with two p-gonal morphisms is given. The image of these configurations on the sphere under the two p-gonal morphisms is also described.

  • 303.
    Jacobs, Stephan
    University of Skövde, School of Engineering Science.
    Genetic algorithm for schedule optimization in the homecare industry2018Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In the last couple of years, the development within the Artificial Intelligence, AI, has rapidly improved with more and more applications to ease daily live. These applications of AI are countless and can lead to a more sustainable and efficient world. AI is there to solve complex problems which are hard to handle by hand for people and give solutions which would otherwise be not reachable in the same timeframe by considering the same variables. One of the applications of AI is to solve scheduling problems, such as the scheduling optimization problem within the homecare industry. Scheduling within the homecare industry is highly demanding since the problem is very complex due to the many different variables which are dependent on each other. Next to this the industry is dynamic in which members and clients come and go. Within the homecare industry employees, from now on called members, are visiting clients for treatments. These visits are at the clients’ home with a certain length and frequency a week, which is different per client. Next to this a client can have multiple assigned members in which they alternate each other. Next to this the client has his or her private schedule with their availability, which are constraints the schedule maker has to take into account. As an understanding of the problem the case study of Malmo stad is used to receive data and develop an algorithm around. The main objective is to develop a programme which solves the scheduling problem within the homecare industry. For this feasible results are needed which thereby meet the constraints of availability, treatment lengths and frequencies, with high importance of the objective of minimizing the travel time. To get sustainable and efficient schedules the algorithm should find the schedule in which the travel time is the lowest. To address the problem, the research strategy of design and development is used. In this the literature in combination with the case study is used to develop and verify the program Within this project an algorithm is developed on the base of a Genetic Algorithm, GA, within MATLAB. Within the GA the fitness of the individuals is determined by feasibility and if the population has reached the maximum fitness, which is that the schedule is feasible and meets the constraints, goes into a fitness which graded by travel time in which minimum travel time is the most optimum. The programme gives as result the schedule per member within the Area for one week. Overall can be concluded that GA can be a solution to address the scheduling optimization problem for the Homecare industry. The algorithm gives solutions which are sufficient and logic. Nevertheless, with a lack of previous data within the industry and no comparison algorithms the verification of the algorithm is hard. Future work has to determine the performance of the GA with respect to this problem.

  • 304.
    Jalderyd, Emil
    et al.
    University of Skövde, School of Engineering Science.
    Legendi, Linus
    University of Skövde, School of Engineering Science.
    Konstruktion av motoruppkopplingsadapter2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The goal of the thesis work is to develop and construct a new solution for connecting engines that goes through a quality check at the testing facility at Volvo Trucks. The thesis work is the final segment of the mechanical engineering program at the University of Skövde.

    Growing demands within manufacturing have led to higher requirements regarding customized products. This puts a higher demand on product variety which leads to greater varieties in production.

    Volvo Trucks manufactures a variety of engines which requires a more flexible way of connecting these different types of engines in the testing facility for testing and quality checks. The current state of this connection is inadequate, improvised and non-flexible. Volvo Trucks have expressed a wish to improve the quality- and testing process regarding the exhaust connection of the engines, as Volvo Trucks are planning a future reconstruction of the testing facility.

    The project started by performing an extensive literature review to investigate how variety in production and demands for a more flexible connection can be solved through product design. The variations that affected the connection between the different motor types and the testing facility were documented and used as a foundation for further work.

    A number of concepts regarding the handling of the different motor types were developed and reviewed with 3D-printed prototypes. A final concept was calculated, dimensioned and constructed. The result shows that it is possible to handle the vast variation in production with the help of robust design. The result also showed that the present connections are oversized and insufficient.

    The authors of this report recommend that Volvo Trucks should continue with implementing the new connection in production to perform tests and develop this connection further.

  • 305.
    Jiang, Yuning
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Atif, Yacine
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Ding, Jianguo
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Wang, Wei
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    A Semantic Framework With Humans in the Loop for Vulnerability-Assessment in Cyber-Physical Production Systems2019Conference paper (Refereed)
    Abstract [en]

    Criticalmanufacturingprocessesinsmartnetworkedsystems such as Cyber-Physical Production Systems (CPPSs) typically require guaranteed quality-of-service performances, which is supported by cyber- security management. Currently, most existing vulnerability-assessment techniques mostly rely on only the security department due to limited communication between di↵erent working groups. This poses a limitation to the security management of CPPSs, as malicious operations may use new exploits that occur between successive analysis milestones or across departmental managerial boundaries. Thus, it is important to study and analyse CPPS networks’ security, in terms of vulnerability analysis that accounts for humans in the production process loop, to prevent potential threats to infiltrate through cross-layer gaps and to reduce the magnitude of their impact. We propose a semantic framework that supports the col- laboration between di↵erent actors in the production process, to improve situation awareness for cyberthreats prevention. Stakeholders with dif- ferent expertise are contributing to vulnerability assessment, which can be further combined with attack-scenario analysis to provide more prac- tical analysis. In doing so, we show through a case study evaluation how our proposed framework leverages crucial relationships between vulner- abilities, threats and attacks, in order to narrow further the risk-window induced by discoverable vulnerabilities.

  • 306.
    Johansson, Gustav
    et al.
    University of Skövde, School of Engineering Science.
    Karlsson, Emelie
    University of Skövde, School of Engineering Science.
    Utveckling av fäste och skyltar för bakrutetorkare på personbilar2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis discloses a bachelor degree project in Product Design Engineering at the University of Skövde. The project was performed in collaboration with a company called The Best of Sweden AB where the assignment was to develop a universal mount and signs for rear window wipers on cars.

    The development process started with a prestudy where customer needs where analyzed. Different factors which affect the product in the environment of use, such as the aerodynamics of cars and the force in the rear window wiper engine, were examined as well during the prestudy. A field study was carried out on existing rear window wipers which became the basis of the dimensions of the signs as well as the mount. The result of the pilot study ended in a list of requirements that the final concept was to be compared to. Different structured design methods was used during concept generation as well as concept evaluation which was followed by a development of the details of the final concept. A proposition of material selection and manufacturing method was determined as well as an estimation of manufacturing cost.

    The result was a fastening device and signs for rear window wipers on cars which makes it possible for the user to mount personalized signs if various different formats. The fastening device consists of a base mount and a strap, where the strap is tightened around the rear window wiper and keeps the base mount in place. The symmetry of the product enables it to be mounted to a rear window wiper that either rotates clockwise or counter-clockwise.

  • 307.
    Johansson, Marcus
    et al.
    University of Skövde, School of Engineering Science.
    Nilsson, Jacob
    University of Skövde, School of Engineering Science.
    Virtuell driftsättning: Verifiering av PLC logik mot simuleringsprogram2015Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To shorten project lead times Volvo Cars Skövde decided to explore the possibilities regarding verifi-cation of PLC-logic in simulation programs. The overall objective of the thesis was to analyze the pos-sibilities for establishing communication between the flow simulation program Plant Simulation and a PLC-device. A thorough understanding of the area virtual commissioning was obtained by writing the frame of reference and a literature review which served as basis for the continued practical work. Through a collection of interviews, discussions and an extensive literature review a better under-standing regarding how the communication between the different programs works, along with im-portant points that should be considered under a virtual commissioning project was obtained. A hy-pothetical system was developed in Plant Simulation by Volvo Cars Skövde to be used as a test sys-tem. The Simumatik3D model was created by emulating the Plant Simulation model and at the same time developing the PLC-logic in Siemens Step 7. During the development progress subsystems were verified in Simumatik3D against the created PLC-logic until the model was fully developed. To make sure that both the Simumatik3D model and the Plant Simulation model was valid a number of valida-tion points were tested. After the validation test the experimental phase started were different sce-narios were analyzed and tested to bring up any problems in the models to the surface. A thorough evaluation is presented in which the entire construction phase of the models is evaluated in terms of time required, advantages and disadvantages and communication with the PLC-device. The two pro-grams Simumatik3D and Plant Simulation was evaluated against one another in order to find out which program that is the most suited for virtual verification of PLC-logic. An overall methodology was developed based on the evaluation carried out and the experience gained from the implementa-tion of the work. The result from the developed methodology is presented which describes the parti-tion between the client and supplier, the communication between them and a visualization of the methodology-process. The result from the evaluation showed that Simumatik3D was more suitable for verification of PLC logic on a detailed level. The evaluation also showed that the PLC logic could be verified with Plant Simulation, but not on the same detailed level. Plant Simulation was more suit-able for making simulation models more realistic. Virtual commissioning of PLC-logic is a new con-cept on Volvo Cars Skövde and therefore can the result from this thesis form a basis for future work in this area. Virtual verification of PLC-logic is discussed in which several important aspects to think about is presented. The projects main goal to virtually verify PLC-logic in simulation programs was achieved and yielded good results, the partial objectives resulted in a thorough evaluation and future recommendations.

  • 308.
    Johansson, Mattias
    et al.
    University of Skövde, School of Engineering Science. matte_j96@hotmail.com.
    Wirdelius, Oscar
    University of Skövde, School of Engineering Science. oscar.wirdelius@gmail.com.
    Utveckling av ett växthus för inom- och utomhusbruk2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The degree project’s purpose was to develop a product following a methodological approach. The product was a miniature greenhouse for indoor and outdoor use, commissioned by a company. The goal of the project was to develop an entire product. An extensive prestudy was performed focused on understanding plants and their needs. Wishes and demands of users were collected by questionnaires and interviews. The answers collected became the basis for many decisions regarding function and form. Furthermore, a lot of focus was on developing a trendy and sustainable product. The development process followed Pahl and Beitz’s model which consists of 4 phases: Planning/specification, Conceptual design, Concept development and Detail design.

    The result is a greenhouse with the possibility for growing in pots or soil. The lid acts as a storage space and encapsulates the synthetic lights that will help the plants grow, especially in climates with less sun. The lid also contains a system that makes watering the plants easier. The modular construction gives the user 360-degree access to the plants from soil level.

  • 309.
    Johansson, Mikael
    et al.
    University of Skövde, School of Engineering Science.
    Persson, Anton
    University of Skövde, School of Engineering Science.
    HALVAUTOMATISERING OCH BEREDNING AV PARTITILLVERKNING2017Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Ett examensarbete har utförts på ett företag där trädetaljer tillverkas. Arbetet gick ut på att förbättra processen vid tillverkning av glaspartier. Företaget är ledande i Skandinavien beträffande sina träprodukter. Tillverkningen sker till stor grad av helautomatiserad produktion men har fortfarande några manuella stationer kvar. Företaget omsätter omkring 450 miljoner kronor per år och har cirka 70 anställda.

    Syftet med examensarbetet var att förbättra processen vid produktion av glaspartier för att reducera den totala operationstiden och minska interna kvalitetsförluster. Huvudmålen var att reducera interna kvalitetsförluster med 10 % samt att reducera operationstiderna med 15 %. För att uppnå målen valdes verktygen go to gemba, frekvensstudie, tidsstudie samt spagettidiagram för att hitta olika slöserier i produktionen och kartlägga operationstiderna. Metod valdes genom att läsa på om de olika verktygen och jämföra dem mot andra verktyg i den teoretiska referensramen.

    Det visade sig att det fanns en del slöserier i processen. Framför allt en hel del onödiga rörelser för både material och för operatörer. Det fanns också många olika lager som varierade i väntetid för det bearbetade materialet under flödet samt en hel del manuellt arbete som företaget helst ville bygga bort. Vid undersökning av nuläget sågs det också att företaget saknade ett standardiserat arbete samt ett 5S arbete i flödet av glaspartier.

    Genom en summering av nuläget kunde ett förbättringsförslag läggas fram. En del av förbättringsförslaget var att bygga bort det manuella arbetet genom att införskaffa en maskin som byggs in i den automatiserade karmlinan. Det leder till mindre kvalitetsförluster, men också färre lager eftersom glaspartitillverkningen kommer att ske i karmlinan. En annan del av förbättringsförslaget var att bygga in slutmonteringen i den befintliga karmlinan där andra liknande produkter redan tillverkades. Som nuläget såg ut var slutmonteringen en separat process vid sidan av karmlinan. Det gjorde att produkterna lades på vagnar och ställdes på ett lager för att sedan ha en lång väntetid innan de monterades. Genom att bygga in slutmonteringen i karmlinan kommer företaget att montera glaspartierna i karmlinan utan onödiga lager. Ett sista förbättringsförslag var att implementera 5s och standardiserat arbetssätt över hela tillverkningen av glaspartier. Det troliga utfallet av förbättringsförslagen beräknades på reducerad operationstid med 59 % och reducerade interna kvalitetsförluster med 80 %

  • 310.
    Jonsson, Martin
    et al.
    University of Skövde, School of Engineering Science.
    Jensen, Tobias
    University of Skövde, School of Engineering Science.
    Utböjningsfenomen vid svarvning av vevaxel - En finita elementstudie2018Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During turning, processes are faced with tough tolerances that can be difficult to maintain due to vibrations and bending. The company Volvo Cars would therefore like to examine the work station OP30, which is a turning process for crankshafts, to better understand why this is. The company has the ambition to implement virtual analyses with the finite element method (FEM) in its production lines. This is sought after to prevent physical examinations which can cause delays due to time-consuming physical tests. In order to investigate the causes for the tolerance not being met, the crankshafts deflection will be examined using FE-analyses that will consider the clamping conditions of the crankshaft, the centrifugal forces and the cutting forces. The natural frequencies of the crankshafts are also examined to confirm that the turning process is not carried out near any critical rotational velocities. 

    In order to verify the FE-analyses performed on the crankshafts, an analytical calculation based on beam theory of a simplified geometry is made using MATLAB. This is then compared with FE-analyses of the same simplified geometry, which shows that solid models used in FE-analyses gives reliable results compared with the beam theory. In order to confirm the deflection that is obtained from the FE-analyses, a measuring method using laser triangulation is developed. This is tested on a lathe at the University of Skövde. 

    The results of this work show that the FEM is a good approach for examining the deflection of a complex geometry. It also shows that the deflection that occurs due to centrifugal forces can be considered small compared to the tolerances that need to be met and the deflection that occurs due to axial displacement of the crankshaft. Therefore the conclusion is drawn that the deflection due to centrifugal forces is not the main source for the tolerances not being met. The work shows that the most important factors to consider are the cutting forces and the axial displacement of the crankshaft. It also shows that there is no risk of resonance occurring within the work parameters of OP30. The work also shows that the measuring method using laser triangulation can be used on a rotating crankshaft, although the equipment used cannot measure the deflection itself.

  • 311.
    Josefsson, Axel
    et al.
    University of Skövde, School of Engineering Science.
    Wedin, Johan
    University of Skövde, School of Engineering Science.
    Convergence properties of a continuum damage mechanics model for fatigue of adhesive joints2014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The effect of the element length is examined in modelling crack growth in fatigue loading of an adhesive joint. This is done for a cohesive element using an expression for the damage evolution developed at the University of Skövde which is implemented using the UMAT subroutine in the FE-solver Abaqus. These analyses are done for pure mode I loading by analysing a DCB-specimen loaded by a pure moment.

    An expression is developed in which the critical element length is dependent on the geometry of the specimen (in the form of the wave number of the adhesive joint), the element length, the material properties of the adhesive (in form of the material parameters , , ), the load applied (in form of the stress in the crack tip), the time step used in the analysis and the crack growth rate.

    It is shown that the results converge by decreasing the element length and the time step used. Therefore an expression for the crack growth rate as a function of the remaining parameters can be determined. Another expression is thereafter developed for the element length needed in order to get a crack growth rate within a certain range of the critical element length. The results show a regular pattern but are not monotone. Therefor two different definitions of the critical element length are tested, either by defining the critical element length as the point where the error is greater than an arbitrary boundary of 1 % of a converged result or where a least square approximation of the error is within 1 % of the converged results. The first method shows a highly irregular result which makes it difficult to develop an expression out of these results. The second method on the other hand gives results that are predictable enough to develop a function out of them. This is done using a regression analysis with all parameters of a third order expression in order to get an expression.

  • 312.
    Juárez Mejía, Gabriel
    et al.
    University of Skövde, School of Engineering Science.
    Soria de la Torre, Julián
    University of Skövde, School of Engineering Science.
    Design of a family of acoustic panels that follows Kinnarps guidelines2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Development of a conceptual proposal of acoustic panels for the Swedish company Kinnarps. The project uses as main methodology Design Thinking with an user centred approach. Secondarily is influenced by the product development process of Ulrich & Eppinger and some IDEO method cards. A literature review that mainly covers acoustics with an emphasis in absorption, a market research, and user studies were performed in order to have a based foundation to create feasible concepts. Along this report is possible to see how the development of the concepts has been done, how they were generated, evolved, and evaluated. As a final result it was proposed a family of 3 different types of structures with 4 variable absorbent panels that ease the way of mounting with a magnetic attachment, and gives several compositions to the customer. It is considered that the final concept fulfils all the demands, although there are some debatable requirements like the functionality, and sustainability that require further development. The methodology and the approach chosen were considered effective tools to work with product design projects that seek an innovative result because they give an appropriate mix of exploration and selection of ideas, and relevant input obtained by the involvement of the users.

  • 313.
    Jönsson, Martin
    University of Skövde, School of Engineering Science.
    Utveckling av hanteringslösning för processat avloppsslam på boendeplattformar i offshore industrin2016Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    This product development project has been carried out in cooperation with the company, Pegil Innovations AB. The purpose of the project was to develop a management solution for processed sewage sludge (dust) on accommodation vessels in the offshore industry. The process of the project combined the Front-End process with details from Set-Based Concurrent Engineering.

    The project started with a preliminary study and user studies to obtain deeper understanding regarding the relevant knowledge area. Details that were of importance to the project was gathered in a specification that was used through the entire process as a support. Then an idea generation was preformed, to discover and explore different solutions. From the idea generation five different idea solutions were created. These five solutions were explored deeper and then compared to a new specification. The specification was an updated version from the first one to better reflect what conditions the idea solutions should meet. When the idea solutions were explored, a new idea generation was performed, resulting in two concepts. These concepts were explored deeper and then compared to a new specification. Then followed another idea generation to explore how the concepts could be improved.

    In conclusion to the project a concept was chosen. The result was a plastic bag which was fastened around a spigot, that was filled with the dust and then the air was withdrawn (to create a vacuum). Then the opening of the plastic bag was heat sealed. The personal could then easily carry the bag to discard this together with the dust.

  • 314.
    Kaartinen, Johanna
    University of Skövde, School of Engineering Science.
    A Checklist for Plastic Product Design: Preventing Pitfalls in a Design Process and Premature Failures of Plastic Products2014Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Designing an injection molded plastic part requires optimizing the part with respect to various stakeholders’ needs throughout its life cycle. The conditions in which a product is operating in service are often inadequately understood or specified, resulting in wrong material selection, which in turn leads to failure when the product is used. Many aspects interrelate with the initial part design and the essential rules of each should be taken into account to ensure a well-functioning plastic product. Regardless, a part design often passes sequentially from concept development to the manufacturing phase with features that unnecessarily complicate production, add costs and weaken the intended embodiment of the product. Therefore, a checklist was developed to ensure that oversights do not happen and verify that a design fulfills the requirements set for it.

    The commissioning company in the project was the design office Sytyte Oy. The aim of this thesis work was to investigate the effects of design decisions on the product’s feasibility and performance in service. The study focused on the underlying reasons for failures in plastic products, failure phenomena and ways of preventing them. The project started with literature research. To support the theoretical review, a small-scale survey was conducted among operators in plastic industry in Finland to strengthen the outcome of the project.

    The findings from the research were compiled into a checklist. The approach into the list was adopted from the FMEA method aiming to create a stripped-down version of it. The result offers a tool for anticipating and spotting possible failures by bringing up the influences that most frequently affect the part performance. It contributes to preventing delays in processing and premature failures in service. The checklist was verified by specialist consultation to receive suggestions and requirements for improvements and to ensure its reliability.

  • 315.
    Kanski, Janusz
    et al.
    Chalmers University of Technology, Göteborg, Sweden.
    Ilver, Lars
    Chalmers University of Technology, Göteborg, Sweden.
    Karlsson, Krister
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ulfat, Intikhab
    Department of Physics, University of Karachi, Pakistan.
    Leandersson, Mats
    MAX IV Laboratory, Lund University, Lund, Sweden.
    Sadowski, Janusz
    MAX-IV laboratory, Lund University, Lund, Sweden / Institute of Physics, Polish Academy of Sciences, Warszawa, Poland.
    Di Marco, Igor
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Electronic structure of (Ga,Mn)As revisited2017In: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 19, no 2, p. 1-8, article id 023006Article in journal (Refereed)
    Abstract [en]

    The detailed nature of electronic states mediating ferromagnetic coupling in dilute magnetic semiconductors, specifically (Ga,Mn)As, has been an issue of long debate. Two confronting models have been discussed emphasizing host band vs. impurity band carriers. Using angle resolved photoemission we show that the electronic structure of the (Ga,Mn)As system is significantly modified from that of GaAs throughout the valence band. Close to the Fermi energy, the presence of Mn induces a strong mixing of the bulk bands of GaAs, which results in the appearance of a highly dispersive band in the gap region of GaAs.

    For Mn concentrations above 1% the band reaches the Fermi level, and can thus host the delocalized holes needed for ferromagnetic coupling. Overall, our data provide a firm evidence of delocalized carriers belonging to the modified host valence band.

  • 316.
    Karlgren, Martin
    et al.
    University of Skövde, School of Engineering Science.
    Berglund, Marcus
    University of Skövde, School of Engineering Science.
    Developing a furniture test machine according to national standards: Ensuring quality and credibility for the SMEEs in South Africa2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In South Africa, where the unemployment rate is immense, Small Micro and Medium Enterprises (SMMEs) provide most of the employment opportunities. But statistics show that a lot of these enterprises fail during their first years of operation. Furntech is an organisation that works within business incubation and skills development for SMMEs in the furniture manufacturing sector in South Africa. Furntech is working on getting an accredited testing laboratory that conforms to South African standards as another service for the SMMEs. The aim of this project is to develop a machine design to test innerspring mattresses that meets the local standards within the bedding industry in South Africa. A field study is conducted to gather information by observations, interviews, and by visiting local manufacturing companies. This is done to fully understand the layout of the actual laboratory and what is required of the machine from a user point of view and mechanical point of view. The design of the machine is developed according to product development methodology and evaluated against demands that are compiled in a requirement specification. 

    A design is produced by developing the existing table test machine in Furntech’s laboratory and is presented in a CAD-model. Existing and required additional parts to support the functionality for the test bedding machine has been evaluated by calculations and simulations by using for example ABAQUS and JACK. Instruction manuals combined with an interface design have been produced, where both of them are connected to a flowchart to understand what is required from the machine, the user, and the programmer.

  • 317.
    Karlsson, Andreas
    et al.
    University of Skövde, School of Engineering Science.
    Butoyi, Guy Igor
    University of Skövde, School of Engineering Science.
    Teknisk analys av felkällor kring äggpaketeringen hos DAVA Foods i Skara: med hjälp av produktionstekniska metoder och verktyg2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    DAVA Foods is a food industry that is one of Sweden's largest companies in the processing and packaging of eggs. The company on which this degree project is carried out in is located in Skara and the work has its main focus on the packaging process of the 24-pack as well as 10-pack egg cartons sold for grocery shopping.The thesis work is to do a technical analysis of sources of errors regarding the egg packaging at DAVA Foods. Students will use various production engineering tools to identify and evaluate improvement proposals on 24-packflow. Students will also identify and evaluate improvement proposals on 10-packflow and identify and evaluate improvement proposals to better alert staff when stops occurs in the process.The PDCA planning tool was used to plan and structure the work once and then a current analysis of flows was made. To gain a better understanding of the current state of the process, observations and interviews were used for data collection. The current position analysis was the base for the work's implementation phase where the root cause tool five why and the fishbone chart diagram was used to find root causes for found problems.The technical analysis of flows resulted in the creation of fourteen improvement proposals, of which eight of these improvement proposals belong to 24-packflow and the remainder to 10-packflows. A pick chart was then used to show which improvement proposals the students believe the companies should implement.The conclusion is that there are two improvement suggestions that should be considered in the 24-packflow. These are to smooth the flow with a new wrapping machine and to extend the conveyor belt, which would reduce wastage that occurs in the process.For 10-packflow, there are two improvements suggestions that should be implemented. These are the implementation of new boxes that have a different lock mechanism than the current ones, and the installation of new light beams to alert the staff the different conditions of the process. A rebuilding of the denester that supplies the flow with the packages, where the task of the denester is to separate the bottom package from the magazine and transport it further to the rotary machine that reverses the package, should also be considered to reduce losses that occur as a result of the packages being damaged in the magazine as the package pile bends when these have been stacked too high.

  • 318.
    Karlsson, Ingemar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    An interactive decision support system using simulation-based optimization and knowledge extraction2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The use of simulation to improve existing manufacturing systems is not new, but simulation can also be used increase the understanding of production systems that have not yet been built. The power of simulation models can be further enhanced by using simulation-based optimization, in which an optimization algorithm tries to find optimal solutions, given certain objectives. However, extracting knowledge from the data resulting from simulation experiments and simulation-based optimization is a complex task. Therefore, tools are needed to assist users in this task. These tools can be visual, like diagrams, or can be generated by data mining. The process of running a study using simulation-based optimization to extract knowledge is a manual task that can in part be automated using existing tools, but to the author’s knowledge there is no software that implements the complete process. This work aims to develop a novel decision support system to support the generic decision process when using simulation and simulation-based optimization. The first step in setting up such a system is to understand how industry currently uses simulation and simulation-based optimization in manufacturing operations. Thus a questionnaire was distributed to manufacturing companies and organizations. The results showed that these techniques are being used, but that companies want more help with the analysis of the results as well as an automated guide in the decision process. This work proposes a system that supports a generic decision process by providing a tool with which a user can define a workflow in their organization, using simulation-based optimization as one component. The decision support system then provides tools for extracting knowledge in the form of diagrams and performs data mining for automated analysis. Data mining is part of the workflow as a tool for extracting knowledge after an optimization, as well as a tool for guiding optimization to suit the users’ preferences. The decision support system also provides for visualization of simulation models and optimization results using augmented reality. A head-mounted display helps users to see the results and model behaviors in 3D. This technology also makes it possible for users to collaborate, both in the same location and remotely. These visual and automatic analysis tools are shown to be effective in several application studies of real-world production scenarios in which data mining has been used to extract important knowledge that would be hard to obtain manually. Together with the automated workflow and efficient visualization of simulation and optimization results in augmented reality, the decision support system is believed to be an effective tool for extracting knowledge for general production systems design and analysis.

  • 319.
    Karlsson, Ingemar
    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.
    Ng, Amos H. C.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Pehrsson, Leif
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Combining augmented reality and simulation-based optimization for decision support in manufacturing2017In: Proceedings of the 2017 Winter Simulation Conference / [ed] W. K. V. Chan, A. D’Ambrogio, G. Zacharewicz, N. Mustafee, G. Wainer, and E. Page, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 3988-3999Conference paper (Refereed)
    Abstract [en]

    Although the idea of using Augmented Reality and simulation within manufacturing is not a new one, the improvement of hardware enhances the emergence of new areas. For manufacturing organizations, simulation is an important tool used to analyze and understand their manufacturing systems; however, simulation models can be complex. Nonetheless, using Augmented Reality to display the simulation results and analysis can increase the understanding of the model and the modeled system. This paper introduces a decision support system, IDSS-AR, which uses simulation and Augmented Reality to show a simulation model in 3D. The decision support system uses Microsoft HoloLens, which is a head-worn hardware for Augmented Reality. A prototype of IDSS-AR has been evaluated with a simulation model depicting a real manufacturing system on which a bottleneck detection method has been applied. The bottleneck information is shown on the simulation model, increasing the possibility of realizing interactions between the bottlenecks. 

  • 320.
    Karlsson, Ingemar
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science.
    Ng, Amos H. C.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science.
    Aslam, Tehseen
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Engineering Science.
    Dudas, Catarina
    Volvo Group Trucks Operations.
    An Interactive, Cloud-Based Simulation Optimization System for Knowledge Discovery and Decision Support In Manufacturing2014In: Proceedings of the sixth Swedish Production Symposium, 2014, 2014Conference paper (Refereed)
    Abstract [en]

    Designing or improving a manufacturing system involves a series of complex decisions over time to satisfy the strategic objectives of the company. To select the optimal parameters of the system entities so as to achieve the desired overall performance of the system is a very complex task that has been proven to be difficult, even for a seasoned decision maker. One of the major barriers for more efficient decision making in manufacturing is that whilst there is in principle abundant data from various levels of the factory, these data need to be organized and transferred into knowledge suitable for decision-making support. The integration of decision-making support and knowledge management has been identified to be more and more important in both scientific research and from industrial companies. The concept of deciphering knowledge from multi-objective optimization was first proposed by Deb with the term innovization (innovation via optimization). By integrating the concept of innovization with simulation, a new set of powerful tools for manufacturing systems analysis, in order to support optimal decision making in design and improvement activities, is emerged. This method is so-called Simulation-based Innovization (SBI), which has been proven to produce promising results in our previous application studies. Nevertheless, to promote the wider use of such a new method requires the development of an integrated software toolset. The goal of this paper is therefore to outline a Cloud-computing based system architecture for implementing such a SBI-based Interactive Decision Support System.

  • 321.
    Karlsson, Ingemar
    et al.
    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.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Bandaru, Sunith
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    An interactive decision support system using simulation-based optimization and data mining2015In: Proceedings of the 2015 Winter Simulation Conference / [ed] L. Yilmaz, W. K. V. Chan, I. Moon, T. M. K. Roeder, C. Macal, and M. D. Rossetti, IEEE Press, 2015, p. 2112-2123Conference paper (Refereed)
    Abstract [en]

    This paper describes a decision support system (DSS) built on knowledge extraction using simulation-based optimization and data mining. The paper starts with a requirements analysis based on a survey conducted with a number of industrial companies about their practices of using simulations for decision support.Based upon the analysis, a new, interactive DSS that can fulfill the industrial requirements, is proposed.The design of the cloud-based system architecture of the DSS is then described. To show the functionality and potential of the proposed DSS, an application study has been performed for the optimal design of a hypothetical but realistic flexible production cell. How important knowledge with respect to different preferences of the decision maker can be generated as rules, using the new Flexible Pattern Mining algorithm provided in the DSS, will be revealed by the results of this application study.

  • 322.
    Karlsson, Ingemar
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Interactive and Intelligent Decision Support in Manufacturing using Simulation Based Innovization and Cloud Computing2014In: Industrial Simulation Conference, Skövde, June 11-13, 2014, 2014, p. 69-74Conference paper (Refereed)
    Abstract [en]

    Simulation-based innovization is a method for extracting knowledge from a simulation model and optimization. This method can help decision makers to make high-quality decisions for their manufacturing systems so as to enhance the competitiveness of companies. Nevertheless, the simulation-based innovization process can be computationally costly and having these resources in-house can be expensive. By running the process in a cloud environment instead, the company only pays for the resources they are using. This paper proposes the concept of a cloud-based computing platform that can run the simulation-based innovization process and discuss its possibilities and challenges.

  • 323.
    Karlsson, Louise
    et al.
    University of Skövde, School of Engineering Science.
    Sjöberg, Alexander
    University of Skövde, School of Engineering Science.
    Framtagning av snabbkoppling i polymera material för vätskekylda datacentraler2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The objective of the Bachelor thesis is to create a concept proposal in collaboration with CEJN. This report is presenting activities involved in the development process used to obtain the final result.

    Referring to the expansive market for liquid cooled data centres, CEJN aims to be in the leading edge with a new quick connection coupling. This demands reduction of production costs relative their existing aluminium coupling, partly by change of material to plastics. Outsourcing is relevant as the company does not produce plastic components at set.

    The idea generation phase has been based on a pre-study consisting of literature studies, analyses of competing products through demolition, and user tests. Prototypes have been used for testing and evaluation throughout the process.

    The outer components of the quick connection coupling proved to be among the costliest details. Locking mechanism, the formation of an inner slot for seals and the junction between nipple- or coupling body and back part to allow assembly and to ensure a non-drip application, have been developed separately. Decisions for final concept selection were made with the company of commission, with data regarding costs, usage interpreted from prototypes and verdicts from external experts within plastics production.

    Sub solutions mentioned, were combined into a final concept which reduces costs and fulfils demands regarding performance, appearance and usability. The material from the project is propositioned to form the basis for further development and testing to ensure high product quality representing CEJN.

  • 324.
    Kashfi, S. Ruhollah
    University of Skövde, School of Engineering Science.
    Towards Evaluation of the Adaptive-Epsilon-R-NSGA-II algorithm (AE-R-NSGA-II) on industrial optimization problems2015Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Simulation-based optimization methodologies are widely applied in real world optimization problems. In developing these methodologies, beside simulation models, algorithms play a critical role. One example is an evolutionary multi objective optimization algorithm known as Reference point-based Non-dominated Sorting Genetic Algorithm-II (R-NSGA-II), which has shown to have some promising results in this regard. Its successor, R-NSGA-II-adaptive diversity control (hereafter Adaptive Epsilon-R-NSGA-II (AE-R-NSGA-II) algorithm) is one of the latest proposed extensions of the R-NSGA-II algorithm and in the early stages of its development. So far, little research exists on its applicability and usefulness, especially in real world optimization problems. This thesis evaluates behavior and performance of AE-R-NSGA-II, and to the best of our knowledge is one of its kind. To this aim, we have investigated the algorithm in two experiments, using two benchmark functions, 10 performance measures, and a behavioral characteristics analysis method.

    The experiments are designed to (i) assess behavior and performance of AE-R-NSGA-II, (ii) and facilitate efficient use of the algorithm in real world optimization problems. This is achieved through the algorithm parameter configuration (parametric study) according to the problem characteristics. The behavior and performance of the algorithm in terms of diversity of the solutions obtained, and their convergence to the optimal Pareto front is studied in the first experiment through manipulating a parameter of the algorithm referred to as Adaptive epsilon coefficient value (C), and in the second experiment through manipulating the Reference point (R) according to the distance between the reference point and the global Pareto front. Therefore, as one contribution of this study two new diversity performance measures (called Modified spread, and Population diversity), and the behavioral characteristics analysis method called R-NSGA-II adaptive epsilon value have been introduced and applied. They can be modified and applied for the evaluation of any reference point based algorithm such as the AE-R-NSGA-II. Additionally, this project contributed to improving the Benchmark software, for instance by identifying new features that can facilitate future research in this area.

    Some of the findings of the study are as follows: (i) systematic changes of C and R parameters influence the diversity and convergence of the obtained solutions (to the optimal Pareto front and to the reference point), (ii) there is a tradeoff between the diversity and convergence speed, according to the systematic changes in the settings, (iii) the proposed diversity measures and the method are applicable and useful in combination with other performance measures. Moreover, we realized that because of the unexpected abnormal behaviors of the algorithm, in some cases the results are conflicting, therefore, impossible to interpret. This shows that still further research is required to verify the applicability and usefulness of AE-R-NSGA-II in practice. The knowledge gained in this study helps improving the algorithm.

  • 325.
    Kedbäck, Miranda
    University of Skövde, School of Engineering Science.
    Exploring Dynamic Complexity in the Symbiosis of Operations and Maintenance Functions: A Simulation-Based Optimisation Study2018Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Maintenance, the process of preserving the condition of the equipment and performance in a production facility, stands for a considerable large cost in the budget of manufacturing organisations and is strongly affected by short-term philosophy. Therefore, both the long-term and short-term consequences of maintenance strategies need to be examined and analysed. The aim with this research is to investigate the dynamic complexity between the requirements from operations on the performance of maintenance, to illustrate the challenge of trading long-term and short-term requirements and benefits. These aspects have been studied through system dynamics (SD) modelling, simulation-based optimisation (SBO) and multi-objective optimisation (MOO). In order to illustrate the analysed problems, a state-of-the-art literature review has been created and two different scenarios have been evaluated. The scenarios are to investigate both the effects of more or less planned maintenance and the implication of a stock-and-flow structure for hiring and retirements of maintenance resources. A conceptual base model, created in previous research, has been applied and developed in order to meet the objectives.

    From the performed experiments, it can be confirmed that with the use of SD simulation trends and consequences over longer periods of time are truly visualised. In the first scenario, the results indicate that a short-term maintenance management strategy is unprofitable over time. The simulation also reveals that improvement strategies and proactive work can revolutionise capability and profit over time, even if these strategies initially generate a higher cost. In the second scenario, where the effects of a major retirement are visualised, the results confirm that the company needs to act proactively in order to avoid great financial losses. Employee and average skill losses cause long-term negative effects on the capability and availability. The optimisation that has been performed, with the hiring rate as the main variable and the objectives of maximising availability, minimising the direct cost and minimising the indirect cost, has generated feasible solutions on the Pareto front.

    In conclusion, the results from the experiments identify the behaviours and causal relationships in a maintenance system in symbiosis with operations. With the long-term goal of generating less reactive workload on the maintenance function, there are many benefits to obtain. The charted delays and causal relationships in the system indicate multi-level consequences, where a management approach should benefit financially from emphasising the importance of acting proactively and directing resources to improvement strategy work.

  • 326.
    Kedbäck, Miranda
    et al.
    University of Skövde, School of Engineering Science.
    Ekdahl, Stellan
    University of Skövde, School of Engineering Science.
    Arbetsstandard, tidsunderlag och förbättringsarbete vid manuella arbetsstationer2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Brodit AB is a company located in Karlsborg, which manufactures holders for technical communication devices for mounting in vehicles. The manual manufacturing, where bending and assembly takes place, lacks a method for standardisation, a base for time scheduling, a base for manpower planning and a method for continuous improvements. The aim of this bachelor thesis was to develop a base for standardised work, time scheduling and manpower planning as well as a method for continuous improvements. To reach these aims a number of sub targets needed to be reached, which were to sustain an analysis of the current situation through observations and time studies, develop standard data for work tasks, divide the tasks into value adding work, non-value adding work and necessary non-value adding work, develop a suggestion to an improved work standard and develop a method for continuous improvements.

    To reinforce choices of methods and conclusions, a number of engineering areas have been studied. Based on the theoretical frame of references, a number of methods for the empirical study were formed.  The study was conducted of observations according to genchi genbutsu, grouping of work tasks, time motion studies performed with a time watch and SAM analysis, calculation of standard data times, evaluation of value adding-, non-value adding- and necessary non-value adding work, SMED analysis and spaghetti diagrams.

    The result of the empirical study was a base for time scheduling with calculated standard times for each work task, where every work task was evaluated as value adding, non-value adding or necessary non-value adding. Based on this, a base for manpower planning can be compiled. The compilation of standard data times as well as the SAM analysis resulted in cycle times far shorter than the cycle times measured in current production. Also, the setup times appeared to be long and irregular with several unnecessary work tasks performed. The result of the spaghetti diagrams also shows unnecessary movements. The conclusion of this is that non-value adding work tasks occurs in the process, that the work is performed in different ways which causes waste in the process and that the work performance rating is below 100 %. With a standardised way of work as well as eliminated non-value adding work tasks, the production could be increased with 60 %; alternatively, the manpower could be decreased with two workers. With the compiled improvement suggestions implemented, the cycle time at the bending working stations could be decreased with at least 50 % and the total setup time could be decreased with at least 57 %.

    A method for continuous improvements has been developed, based on a PDCA cycle. With improved conditions on each working station and a standardised way to work, possible improvements can be achieved in reduced setup times, reduced cycle times as well as the implementation of a culture of continuous improvements. 

  • 327.
    Kjellén, Linus
    et al.
    University of Skövde, School of Engineering Science.
    Björnell, Jonna
    University of Skövde, School of Engineering Science.
    Ställtids- och kassationsreducering, svarvning2016Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Ett examensarbete är utfört på ett tillverkande företag med cirka 140 stycken anställda och utför skärande bearbetning i stål, aluminium och gjutjärn till bland annat bil-, telekom och övrig verkstadsindustri. Produktsortimentet består till största delen av kopplingar till ramlager, medbringare, fyrhjulsdrifter och robotkomponenter. Företaget har en svarvgrupp med tre stycken CNC-svarvar som har problem med långa omställningstider och det upptar en stor del av produktionstiden. Det försvårar för svarvgruppen att leverera produkter i tid, i samband med omställningarna förekommer även en stor mängd kassationer som orsakar kostnader och som även är en bidragande orsak till de långa omställningstiderna.

    Syftet och huvudmålen var att reducera omställningstiden med 30 %, minska kassationer vid omställning med 30 % och att ta fram lämplig metod för ställtidsreducering. För att uppnå syftet och huvudmålen valdes metoden Single Minute Exchange of Die (SMED) som är en metod för att reducera omställningstid. Valet gjordes utifrån en litteraturstudie där metoden visat sig vara resultatrik i liknande fallstudier.

    Med användning av videodokumentation, spagettidiagram och kassationsdokument kunde nuläget fastställas i svarvgruppen. Orsakerna till den långa omställningstiden och kassationerna varierade, en stor anledning till deras långa omställningstider var att de genomförde alla aktiviteter under den inre omställningen. En annan anledning var att svarvgruppen saknade ett standardiserat arbetssätt samt struktur och framförhållning i arbetet.

    Utifrån nulägesanalysen utvecklades förbättringsförslag som implementerades inför en pilotstudie som kunde frambringa ett resultat. Omställningen kunde reduceras med 38 % och kassationer i samband med omställning reducerades med 50 %. Resultatet av studien visar även att metoden är lämplig för fortsatt arbete med ställtidsreducering för svarvgruppen. Genom implementering av SMED metoden har omställningstiden och kassationerna reducerats, vilket medför en ökad flexibilitet eftersom det finns en större förmåga att snabbt genomföra en omställning från en produkt till en annan och snabbare bemöta kundernas efterfrågan.

  • 328.
    Klarin, Johanna
    et al.
    University of Skövde, School of Engineering Science.
    Johansson, Alexander
    University of Skövde, School of Engineering Science.
    Utveckling av en moduluppbyggd destinationsskylt2015Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A modular destination sign for buses was developed. The work was performed at the University of Skövde in cooperation with the company Mobitec AB that for instance sells the signs that was currently used in the city buses in London. The sign that was developed was meant to serve as a replacement for the signs with printed blinds that were existing in the London city buses. The sign therefore had to live up to the demands on the resolution and readability. This would be achieved by building up the sign with a modular system of Superfine Pitch LED Matrix Card.

     

    The modular system needed to sustain vibrations from the bus and allow individual modules to be easily assembled and disassembled. To develop a functioning system guidelines for DFA and DFD was used, and user needs from installers and repairers were investigated. During the concept generation set-based concurrent engineering was used to avoid further development of non-functioning concept at the expense of elimination of good concepts.

     

    Three remaining, equivalent concepts were modeled and tested for vibration by doing simulations in Creo Parametric 2.0. The vibrations were also tested on 3D-printed models from CAD files. The results showed that all the solutions managed the vibrations. The final concept selection was made by matrices and by usability testing.

  • 329.
    Kolbeinsson, Ari
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Managing Interruptions in Manufacturing: Towards a Theoretical Framework for Interruptions in Manufacturing Assembly2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The effect of interruptions from ICT systems on assembly workers in manufacturing is examined in this thesis, as is how the risks of errors, increases in assembly time, increased cognitive load and resultant stress can be mitigated, as well as ensuring that important new information is acted upon. To these ends, a literature study was conducted, followed by two studies using an experimental approach in an environment that simulated a manufacturing assembly situation, and used tasks designed to be representative of manufacturing assembly tasks. The results of the literature study and the two studies are presented in four appended papers. The body of the thesis itself introduces similar material, and takes a step towards the creation of a theoretical framework that supports analysing the tasks and environments in question from a embodied and situated (DEEDS or 4E) viewpoint on cognition. This theoretical framework uses graphical representations similar to storyboards to support the analyst in maintaining an embodied and situated viewpoint during analyses of active tasks that require an examination of the interplay between brain, body, and environment. Supporting an embodied viewpoint during analysis has the purpose of facilitating the design of interruption coordination systems that take into account the embodied and situated nature of the tasks faced in manual tasks such as assembly in manufacturing.

  • 330.
    Kolbeinsson, Ari
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Situating interruptions in manufacturing assembly2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Interruptions have been studied extensively, with interruptions experiments where tasks performed on computers are interrupted by another task received on the same computer having receiving much of the focus. Additionally, many of the tasks used in existing research have been designed specifically to test the effect of interruptions on humans by making both the interrupting task and the task being interrupted quite difficult. The studies introduced here show that these commonly used tasks do not accurately represent some aspects of the manual tasks commonly performed by humans outside of laboratory experiments, with the experiments in this thesis focusing on manual tasks in assembly. A notable difference identified here is that interruptions in manual assembly tasks were seen to always contain a negotiation element, meaning that the person being interrupted could always modify to some extent when to respond to interruptions. Another central finding is that breakpoints for smart interruption systems need to be chosen using even more care than suggested by existing research because of an effect that can cause a notification to be completely missed when sent at a point that seemed opportune. This is due to apparent lulls in the activity containing preparation for the next action, or anticipation of action, using the Activity Theory (AT) terms used in the analysis of this effect. AT was identified as a useful tool for the analysis of manual assembly as it supports a hierarchical analysis of the activity and takes into account operator skill (task familiarity) in an easy to understand manner.AT was further used in an observational study where current approaches to interruption management were observed and explored. A surprising conclusion was that classical interruptions, as commonly defined, where one task is interrupted and another task must be completed before resuming the main (primary) task were exceedingly uncommon. This was found to be due to the high task familiarity (skill level) of the workers, the assembly activities being designed to minimise the risk of interruptions, and workers being trained to always finish the current operation before switching to another task. Workers did however engage in conversation and an interesting style of communication, dubbed ebb-and-flow style of negotiation, was identified. The differences between the results found in literature and the results of the studies were synthesised into a theoretical framework, or a collection of theories that work together to support the analysis of interruptions, and a visual support tool for the theoretical framework was created. This visual support tool, called an activity board both binds together the theories in a way that should make the theoretical framework easier to understand, and provides the beginnings of an analysis tool for interruption using the framework.

  • 331.
    Kolbeinsson, Ari
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lagerstedt, Erik
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Classification of Collaboration Levels for Human-Robot Cooperation in Manufacturing2018In: Advances in Manufacturing Technology XXXII: Proceedings of the 16th International Conference on Manufacturing Research, incorporating the 33rd National Conference on Manufacturing Research, September 11–13, 2018,  University of Skövde, Sweden / [ed] Peter Thorvald, Keith Case, Amsterdam: IOS Press, 2018, p. 151-156Conference paper (Refereed)
    Abstract [en]

    Industry 4.0 aims to support the factory of the future, which involves increased amounts of information systems and new ways of using automation. One new usage is collaboration between human and industrial robot in manufacturing, with both partners sharing work on a single task. Supporting human-robot collaboration (HRC) requires understanding the requirements of HRC as well as the differences to existing approaches where the goal is more automation, such as in the case of self-driving cars. We propose a framework that we call levels of collaboration to support this, and posit that this framework supports a mental model conducive to the design of lines incorporating HRC.

  • 332.
    Kolbeinsson, Ari
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lagerstedt, Erik
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Foundation for a classification of collaboration levels for human-robot cooperation in manufacturing2019In: Production & Manufacturing Research, ISSN 2169-3277, Vol. 7, no 1, p. 448-471Article in journal (Refereed)
    Abstract [en]

    Industry 4.0 aims to support the factory of the future, involving increased use of information systems and new ways of using automation, such as collaboration where a robot and a human share work on a single task. We propose a classification of collaboration levels for Human-Robot collaboration (HRC) in manufacturing that we call levels of collaboration (LoC), formed to provide a conceptual model conducive to the design of assembly lines incorporating HRC. This paper aims to provide a more theoretical foundation for such a tool based on relevant theories from cognitive science and other perspectives of human-technology interaction, strengthening the validity and scientific rigour of the envisioned LoC tool. The main contributions consist of a theoretical grounding to motivate the transition from automation to collaboration, which are intended to facilitate expanding the LoC classification to support HRC, as well as an initial visualization of the LoC approach. Future work includes fully defining the LoC classification as well as operationalizing functionally different cooperation types. We conclude that collaboration is a means to an end, so collaboration is not entered for its own sake, and that collaboration differs fundamentally from more commonly used views where automation is the focus.

  • 333.
    Kolbeinsson, Ari
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mind the body: How embodied cognition matters in manufacturing2015In: Procedia Manufacturing, ISSN 2351-9789, Vol. 3, p. 5184-5191Article in journal (Refereed)
    Abstract [en]

    Embodied cognition can provide human factors and applied ergonomics practitioners with better embodied cognition design principles. This paper investigates and analyzes observational video-recorded data from an experiment that simulated a manufacturing environment. The operator was interrupted during a primary assembly task via a handheld computing device which delivered different classes of notifications. The focus is on the embodied aspect of notifications in an active environment, and why one class of notifications called mediated notifications failed at a specific point previously thought to be suitable. Guidelines for analyzing tasks from an embodied cognition perspective that complements and expands traditional human factors and applied ergonomics approaches were developed and are included.

  • 334.
    Kolbeinsson, Ari
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Thorvald, Peter
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Missing mediated interruptions in manual assembly: Critical aspects of breakpoint selection2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 61, p. 90-101Article in journal (Refereed)
    Abstract [en]

    The factory of the future aims to make manufacturing more effective and easily customisable, using advanced sensors and communications to support information management. In this paper, we examine how breakpoint selection during interruption management can fail, even when using recommendations for interruption management from existing research. We present an experiment based on prior work where mediated interruptions (i.e. smart interruptions that should interrupt at opportune moments) were missed by participants when sent at one of two pre-defined breakpoints. These breakpoints were selected based on existing research to minimise the cost of interruption, which can involve longer times to complete tasks as well as making errors on tasks. Missing mediated interruptions in this way was unexpected, and the prior study was not configured to measure this effect, which has led to the experiment detailed here. We strive to explore whether there is a risk of missing notifications when mediated interruptions are used, and how this is affected by breakpoint selection. This was investigated through an experiment that uses tasks and environments that simulate a manufacturing assembly facility.

    The results indicate that the effect exists, i.e. that participants miss significantly more notifications when interrupted at fine breakpoints than when interrupted at coarse breakpoints. An embodied cognition perspective was used for analysis of the tasks to understand the cause of the effect. This analysis shows that an overlap between “action” and “anticipation of action” can account for why participants miss notifications at fine breakpoints. Based on these findings, recommendations were developed for designing interruption systems that minimise the costs (errors and time) imposed by interruptions during assembly tasks in manufacturing.

  • 335.
    Kolbeinsson, Ari
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Thorvald, Peter
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Context aware interruptions: Existing research and required research2014In: Advances in Cognitive Engineering and Neuroergonomics / [ed] Kay Stanney & Kelly S. Hale, AHFE , 2014, p. 260-272Conference paper (Refereed)
    Abstract [en]

    Companies in various fields are developing information systems that are supposed to show information in a context sensitive manner. This involves modifying user interfaces based on the current activity and location of the user. The research that exists for context aware, task aware, and location aware systems come mostly from research in the office environment and using stationary work computers using standard mouse and keyboard-operated systems. Other environments, such as manufacturing environments, have not received the same research attention, and therefore research is required to see whether existing theories and frameworks apply to the manufacturing domain. Adding to this, context aware systems are now being created for new classes of devices such as mobile and wearable devices, to be used in multiple domains. All this requires an investigation and validation of older research, and shows how the research of the basic human factors surrounding new devices and domains has fallen behind the development of the devices themselves. This paper examines shortly how recent changes advances in technology affect what is required from the field of interruption research, as well as what is needed to support other domains than the office environment. 

  • 336.
    Kolbeinsson, Ari
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Thorvald, Peter
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Coordinating the interruption of assembly workers in manufacturing2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 58, p. 361-371Article in journal (Refereed)
    Abstract [en]

    This paper examines how interruptions from information and communications technology systems affect errors and the time to complete tasks for assembly workers. Interruptions have previously been examined in laboratory experiments and office environments, but not much work has been performed in other authentic environments. This paper contains the results of an experiment that was performed in a simulated manufacturing assembly environment, which tested the effects of interruptions on a manual assembly task. The experiment used existing interruption coordination methods as a basis, and the results showed a difference in the effect of interruptions and interruption coordination between cognitively complex laboratory tasks and manual assembly tasks in an authentic environment. Most notably, the negative effects of interruptions delivered without consideration were smaller in this experiment. Based on these findings, recommendations were developed for designing interruption systems for minimizing the costs (errors and time) imposed by interruptions during assembly tasks in manufacturing.

  • 337.
    Koskenranta, Mikael
    University of Skövde, School of Technology and Society. University of Skövde, School of Engineering Science.
    Optimisation of ceiling attachment for AVPOS using FEA2015Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In product manufacture and assembly it is important to lower materials usage and assembly timewhile retaining a safety margin against structural failure. In this project the ceiling attachment of theAVPOS offloading arm is redesigned based on objectives identified by Löfs Specialmaskiner. Theoriginal ceiling attachment is analysed using finite element analysis to identify any structuralweaknesses to be addressed during redesign. Based on information gained during the FEA threeconcepts are generated and rated based on their estimated assembly times, material usage, partscount and the cutting length for machining.One concept is selected for further topology optimisation and iterative FEA, where material isremoved from the selected concept design while maintaining safety objectives. The optimised designdeveloped during this project is shown to have a lower number of parts, lower usage of material andassembly time while retaining an overall FOS value of 4.In addition to redesigning the ceiling attachment, alternative bearings are also investigated whichchanges the existing ball bearings to a self-aligning sliding bearing with self-lubricating properties,lowering the machining tolerances as well as lowering the needs for service.This project contributes to lowering material usage and ease of assembly in the product AVPOS thatis manufactured by Löfs Specialmaskiner. The redesigned ceiling attachment along with thesuggested bearings will likely simplify future manufacturing as well as lower any concerns for damageto people and property as a result of structural failure.

  • 338.
    Krantz, Johan
    et al.
    University of Skövde, School of Engineering Science.
    Krantz, Stefan
    University of Skövde, School of Engineering Science.
    Förslag på utformning av Kitt- och Sekvensering inför nästa generations motor: På Volvo Cars i Skövde2016Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Volvo Cars Skövde will in year 2018 implement a new engine model in Skövde plant, which will lead to a greatly increased variety of the articles in the material facade at the production line when the engine variants increases. However, the current material facade will not be able to cope with the future increase of articles. Therefore, design proposals for the handling of the material by using kit- and sequence picking externally from the production line have been proposed. Hence, handling these operations externally may lead to an efficient material flow, but also enables handling more articles when the engine variants increase.

    The main objective of the project was to develop proposals on how workplace design for a kit- and sequence picking station may look like, and how the flow of material should be handled to and from these stations. To implement this, a form of a PDCA-method has been used to structure the work. Relevant literature on the theory and studies in similar areas has been reviewed to gather knowledge in this area. Successful methods used in other studies, i.e. interviews, observations and benchmarking, were also used in this project to collect data.

    The results based on the collected data generated, present different layout suggestions of a kit- and sequence picking station, with regard to quality assurance and efficiency of the picking patterns, ergonomics, reliability of delivery and the total area required for these picking stations. It will also manage the flow of materials to and from these stations that should be handled in an efficient way. Prototype sketches of proposed way of transport and aid for the material handling have been developed for the company, which will be a base for continued work before the implementation of the next generation engine in year 2018. 

  • 339.
    Kurbanov, David
    et al.
    University of Skövde, School of Engineering Science.
    Gómez, Cristóbal
    University of Skövde, School of Engineering Science.
    Input Data Analysis for Detailed Flow Simulation of Manual Assembly Lines2019Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    This thesis work was carried out at a manufacturing plant in Sweden and they are producing a different kind of components for the company. This thesis work was about an assembly line in the factory where they needed a simulation model in Plant Simulation. The main goal of the thesis work was to break down different losses, building a simulation model and compare it if the results are the same as the real assembly line with similar characteristics. The assembly line consists of several workers and AGVs with three u-shaped lines.

    Frame of reference describes topics that are related to the project. It consists of theories about simulation, collection of data, the bottleneck of the production line, integrated manufacturing systems and flexible workers. The chapter of literature review presents researches on similar studies, in this case, simulation, bottleneck, and workers in the assembly line.

    In the chapter Simulation model, there will be an explanation of how data got collected, the transformation of raw data and building a simulation model of it. Also the way the model was programmed and built. Result and analysis, the focus is to analyze the throughput, lead time and work in process parameters to get a steady state graph and confidence interval. This chapter also shows how long time does the model need for warm up and how many replications it needs to be more accurate.

    Discussion part reviews the whole project and its progress. It covers problems that authors got through, at the same time learning and getting a new experience of tools and methods that were used in this project.

  • 340.
    Kälström, Matilda
    University of Skövde, School of Engineering Science.
    UTVECKLING AV EXKLUSIV KLÄDKAMMARE OCH FÖRVARINGSLÖSNING FÖR PRIVATHEM2015Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Design Engineering student Matilda Kälström has developed a range of storage solutions for walk-in closets where the target group for the project is the company’s existing customer base. During the project a basic feasibility study was done to determine the project requirements, identify competitors and find out what demands and requests the customers have. Example of demand was that the product should provide an overview of the content of the walk-in-closet. A literature study was done to gather information about storage, man's relationship to its home and architecture. Identified information was that it's very important for the human to be able to design their home according to their needs and a good guideline to structure storage is to place the clothes according to where on the body they are used.

    A central part of the project is Kansei engineering, which is a concept of connecting peoples’ perceptions to products' design. It has been used in surveys to find out what the customers want to experience, it has been used for idea generation and it has been used to find out if the results gave desirable experiences. The survey results revealed that desirable experiences of a walk-in closet is luxurious, classic, stylish and comfortable. The meaning of these words were used from the National Encyclopedia to make mood boards which then were used to generate ideas.

    The development of ideas were made in three stages with different methods. After each stages the concepts were evaluated and the results were used in the next stage. The methods that were used was for example personas, scenarios, function trees and morphological table. The evaluations was performed with the company, the method PNI and a weighting matrix.

    The result is a collection of twelve modules that customers can combine in their own way of walk-in closets. Four different cabinet modules, two different “storage islands”, two seats, a dressing table, a chest of drawers for jewelries, a shoe rack and a mirror shelf. To finally find out if the result gives the perceptions and experiences that is desirable an evaluation was done with twelve people, mostly students at the University of Skövde. Two different mounting of the modules in the form of a "female" and "male" walk-in-closets were shown. With their own words they were about to describe what impressions they had of the pictures and tell what they thought of these walk-in-closets. The participants' response strengthened the project's results and confirmed that the impressions and experiences were desirable. 

  • 341.
    Kärmander, Adam
    et al.
    University of Skövde, School of Engineering Science.
    Nori, Daniel
    University of Skövde, School of Engineering Science.
    Produktionstekniskt förbättringsarbete hos Dava Foods: Förbättrande av en maskin2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts på Dava Foods i Skara. Det är ett företag där hönsägg i olika kvaliteter bearbetas. Där finns en äggknäckningsprocess som består av två maskiner. Organisationen har problem med maskinen som har till uppgift att separera brickor och ägg. Den stannar alltför ofta och därför har företaget bett om hjälp.

    Syftet med arbetet var att ta reda på vilka orsaker som ligger bakom stoppen och att ge förbättringsförslag för att förhindra framtida oönskade stopp. Observationer och intervjuer genomfördes för att få en bättre förståelse för hur maskinen fungerar. Därefter utfördes fyra stopptidsanalyser för att dokumentera stilleståndstider och för att det skulle vara möjligt att se vad som får maskinen att stanna. Metoden 5 x varför användes för att hitta rotorsakerna till problemen. Förbättringsförslag gavs utifrån de rotorsaker som identifierades och även utifrån egna tankar och idéer. Dessa förslag placerades även in i två PICK-charts så att organisationen eventuellt kan välja att implementera några av dessa i framtiden.

    Arbetet resulterade i 12 unika förbättringsförslag. 2 av dessa hade med brickornas material att göra. Det ena förslaget innebar att endast använda plastbrickor och det andra var en blandning av plast- och pappersbrickor. Ytterligare ett förslag var brickor med 5x5 ägg, vilket innebär att brickan ska ha plats för 5 ägg på bredden och 5 på längden. Tre förbättringsförslag hade med människor att göra. Dessa handlade om att operatören ska försöka vara mer noggrann med avståndet mellan brickor på första rullbandet, att människor ska vara försiktiga vid transport och hantering av äggen samt att det ska vara tre personer som arbetar vid maskinen. Några mer omfattande förbättringsförslag var ett längre första rullband, en robot vid första rullbandet, en bättre funktion som separerar brickor, en ny maskin och en annan layout. Det föreslogs även att minska hastigheten på den så kallade cylindern.

    Slutsatsen är att det finns tre förbättringsförslag som verkligen bör övervägas. Dessa är användning av plastbrickor istället för pappersbrickor, införskaffande av en ny maskin samt tre personer som arbetar vid maskinen. Om plastbrickor används istället för pappersbrickor så hade det blivit mycket mindre stopp. Detta gäller även för en ny maskin som kan hantera både plast- och pappersbrickor. Om tre personer arbetar vid maskinen så kan den tredje personen ha som arbetsuppgift att upptäcka och åtgärda fel innan dessa får maskinen att stanna.

  • 342.
    Kärrlander, Daniel
    et al.
    University of Skövde, School of Engineering Science.
    Nordström, Marcus
    University of Skövde, School of Engineering Science.
    Utveckling av fiberoptisk ljusgenomföring för lägenhetsdörr2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This is a report which covers the bachelor degree project in Product Design Engineering at University of Skövde. The project is conducted in cooperation witha company that manufactures doors and wants to expand their accessory rangewith a product in the market segment between windows and LED-lights toilluminate the very entrance of an apartment and provide the user with sufficientlight. The development process for this product began with a comprehensiveprestudy followed by identification of relevant environments, collection of targetdata through measurements of illumination, and theoretical calculations ofproduct geometries such as light collecting area. The combined knowledge led toa generation stage, evaluation stage and prototype production. The result becamesubstandard and did not reach the desired lighting effect with the identifiedboundary conditions due to unforeseen power losses. If the product is taken outof these boundaries and instead used in more favorable conditions, the result issignificantly better.The conclusion is that passive collection of diffused light is possible but noteffective and above all incompatible with, in this case, high security and demandsfor low costs.

  • 343.
    Ladrón de Guevara Muñoz, M. Carmen
    et al.
    University of Skövde, School of Engineering Science.
    Martín Márquez, Javier
    University of Skövde, School of Engineering Science.
    Mini-grid system study applied to a stand-alone house located in Málaga, Spain2015Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    A study of an off-grid photovoltaic system for the electrification of a stand-alone single residential house in a rural area located in the city of Málaga, Spain, is presented. The load of an average family house is analysed keeping in mind the available solar energy at this location. A preliminary sizing of the system is carried out considering predefined values for the efficiency of the different technologies employed in the system: photovoltaic (PV) array, batteries as energy storages, inverters to convert the energy obtained from the sun, and diesel gensets to ensure supply under any circumstances. Later, precise brands of the available technologies in the market are selected, and the system is re-sized using the new parameters. The life cycle cost of the mini-grid (MG) system shows that the amortization of the system in 20 years for a stand-alone house is not possible. Although it is not confirmed that 20 years will be sufficient to make the system profitable, other aspects are considered and discussed in terms of their feasibility in Málaga.

  • 344.
    Lageholm, Joel
    et al.
    University of Skövde, School of Engineering Science.
    Dia, Mohammed
    University of Skövde, School of Engineering Science.
    Hållfasthetsanalys och vidareutveckling av skopa för traktorer med frontlastare2018Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A bucket, designed and constructed by the company Kellfri AB for all-round usage with front-end loader equipped tractors, has been analyzed via finite element analysis in Creo Parametric. Possibilities of mass reduction, suitability in the placement of an additional detail in the upper parts of the bucket and potential strength problems in the construction was investigated. The project was initialized during the prototyping-phase of product development and at the time the bucket was considered to be over dimensioned by the company with regard to their earlier prototype-testing. Static analysis was done for three separate models; The Company’s own CAD-model, for which the strength of the bucket, as it was originally designed, was evaluated. A second model was made for the use of iterative changes in the construction, each followed by an analysis, to test different solutions for reducing the buckets mass without compromising strength and to address strength issues found in the original model. A third model, comprised of a simplified section of the buckets front, was then used to further evaluate and address the most critical of the strength problems that was found. The bucket was, at the end of the project, considered to be inadequately dimensioned for one of the features of the suggested front-end loader model. Suggestions was therefore given, with probable uncertainties accounted for, regarding a suitable area for mass reduction, changes in the design with the possibilities of cost-reduction by simplifying the manufacturing and assembly processes and also actions to be made in regard of strength problems found. Placement of the upper part-detail was considered safe and therefore given a suggested shape.

  • 345.
    Land, Niklas
    University of Skövde, School of Engineering Science.
    Towards implementing collaborative robots within the automotive industry2018Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Collaborative robots have many advantages and have proven to be useful, although there are still currently very few actual implementations of collaborative robots on the industrial shop-floors. One major reason for this is the high safety requirements within the industry and the difficulties to fulfil current safety regulations when using collaborative robots. The purpose of this thesis is to identify the most important safety aspects in collaborative robot applications and to discuss how different solutions can aid in fulfilling current safety regulations. In order to fulfil the purpose, a physical demonstrator will be developed in collaboration with Volvo Cars Engine that can be used for evaluation and testing. To investigate what the general opinion of the automotive industries thoughts are on collaborative robots, a questionnaire based survey was conducted with 143 participants. The survey result show that the majority thinks that collaborative robots can benefit them in their own work, and that assembly- and material handling tasks is well suited applications for collaborative robots. The literature review of the thesis project is focused on collaborative robot safety peripherals for minimizing injury by collisions, but also to investigate other related work with collaborative robots. Input from the survey and the literature review clarifies the problem at hand and tentative idea of a physical demonstrator is suggested. The demonstrator which resembles an industrial assembly station with bolt tightening, has been created using a light weight structure UR10 robot from Universal Robots. Together with the operator, a work sequences was proposed for both the human and the robot, and once implemented, three optional scenarios where recorded for evaluation. By observing the recordings it is identified that a seamless workflow can be achieved even though the robot and human works in the same area and on the same work piece. Other benefits include improved ergonomics and reduction of operator physical fatigue. To evaluate the demonstrator further, experiments with test- and control groups were proposed as future work.

  • 346.
    Land, Niklas
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Almgren, Torgny
    GKN Aerospace Sweden AB, Trollhättan, Sweden.
    Vallhagen, Johan
    Volvo Group Trucks Operations, AB Volvo, Gothenburg, Sweden.
    Virtual Human-Robot Collaboration: The Industry's Perspective on Potential Applications and Benefits2019In: Advances in Manufacturing Technology XXXIII: Proceedings of the 17th International Conference on Manufacturing Research, incorporating the 34th National Conference on Manufacturing Research, September 10–12, 2019, Queen’s University Belfast, UK / [ed] Yan Jin, Mark Price, Amsterdam: IOS Press, 2019, Vol. 9, p. 161-166Conference paper (Refereed)
    Abstract [en]

    Two keystones of Industry 4.0 are the increased use of autonomous robots and advanced simulation software. Human-Robot Collaboration (HRC) combines the strengths of humans and robots, opening up application areas that previously could not be automated. However, the realization of HRC on industrial shop floors is held back by several challenges: safety, trust, the need for intuitive interfaces, and design methods. This study investigates the automotive industry’s perspective on relevant application areas and potential benefits of HRC. The data were collected through a survey of 185 participants from a variety of working roles in the automotive industry. The results of the study indicate that participants from the automotive industry consider that the areas best suited to the implementation of collaborative robots are material handling, assembly, and quality control, with potential benefits in ergonomics, efficiency, and quality. The results can be used for the development of a future virtual HRC simulation model.

  • 347.
    Larsson, Carina
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Communicating performance measures: Supporting continuous improvement in manufacturing companies2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Manufacturing enterprises are a key driver of economic growth (Eurostat, 2016). Implementing continuous improvement (CI) is commonly used to increase competitiveness (Hyland et al., 2007), but despite the well-known theory of CI, many manufacturing companies fail in implementing it (Bhasin, 2012; Nordin et al., 2012; Tiwari et al., 2007).

    An identified critical success factor in CI implementation is the evaluation of performance, including the performance evaluation system itself, the linkage between targets at different company levels, and continual evaluation of performance (Bakås et al., 2011; Scherrer-Rathje et al., 2009; Ukko et al., 2009). Another critical success factor in CI implementation is the communication of performance measures (Bakås et al., 2011; Ukko et al., 2009).

    This research explores the communication of performance measures. The aim is to support CI by improving the communication of performance measures, and to this end, this thesis concentrates on identifying the main challenges in the communication of performance measures supporting CI. The research scope is manufacturing companies in general, and manufacturing SMEs in particular. The relevant literature concerning the communication of performance measures in manufacturing companies is identified and summarized. Also, current practice is explored, focusing on how performance measures are communicated in manufacturing companies, and whether and how the communication supports CI. This has been done to identify divergences between current practice and theory. Finally, theory and empirical findings are synthesized to identify some of the main challenges to be addressed in order to succeed in CI.

    The main task is to support CI efforts in manufacturing SMEs, eliminating the identified divergences in the communication of performance measures by adapting these measures to these manufacturing SMEs. These challenges can be summarized as follows: 

    - using both financial performance measures as well as objective and subjective, non-financial performance measures  - aligning performance measures with strategy and targets  - integrating all performance measure communication, as related to both daily performance and CI, in the same communication loop.  - forming two-way communication channels between managers and operators  - aligning oral and written communication channels  - exploring how information systems can facilitate the communication of performance measures  - using and optimizing the visual communication of performance measures

  • 348.
    Larsson, Carina
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Strand, Mattias
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Persson, Anne
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Communicating continuous improvement in manufacturing companies: Divergencies between current practice and theory2017Conference paper (Refereed)
    Abstract [en]

    Succeeding with continuous improvement is important for manufacturing companies to increase the competitive edge. In order to succeed with continuous improvement, literature shows that communication of improvement indicators need to be integrated with communication of control indicators. This paper identifies divergencies between current practice and theory in the communication of CI, which can be a reason for why manufacturing companies fail in their CI implementation. An integration of control indicators and improvement indicators could improve continuous improvement results, increasing business performance.

  • 349.
    Larsson, Carina
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Säfsten, Kristina
    Jönkoping University, Jönkoping, Sweden.
    How to visualize performance measures in a manufacturing SME2017In: Measuring Business Excellence, ISSN 1368-3047, E-ISSN 1758-8057, Vol. 21, no 4, p. 337-350Article in journal (Refereed)
    Abstract [en]

    Purpose - The purpose of this paper is to identify strengths and weaknesses in the communication of performance measures and propose guidelines for the visualization of performance measures supporting continuous improvement (CI) in manufacturing small and medium-sized enterprises (SMEs). The goal is to help manufacturing SMEs improve their communication of performance measures, thereby improving performance, and strengthening the company. Design/methodology/approach - This paper draws on both theoretical and empirical research. It begins with a literature review of theoretical guidelines for the visualization of performance measures. This theoretical information is then supplemented with a case study and a survey, both carried out at the Vara plant, a manufacturing SME with well-developed communication of performance measures. The case study involved all organizational levels in the company and focused on identifying strengths and weaknesses in visual communication of performance measures supporting CI. The information acquired from the literature survey and the case study was then used as the basis for a survey of the employees in one department as regards their perception, understanding and opinion of visual communication of performance measures. The analysis of the results led to the development of guidelines and a substantive proposal improving visualization of performance measures in this specific company, and in manufacturing SMEs in general. Findings - A model for the visualization of performance measures supporting CI in the company was carried out. The guidelines proposed for all such visualizations are as follows: keep the visualization as simple as possible without compromising understanding, use symbols and colors consistently, use simple words and do not include too much information in the visualization. The study also shows that it is important to support a written visualization with an oral presentation to explain the results. Originality/value - The originality of this paper lies in its focus on the visualization of performance measures in manufacturing SMEs and the guidelines and proposals developed.

  • 350.
    Larsson, Carina
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. University of Jönköping.
    Säfsten, Kristina
    University of Jönköping.
    Visual communication of performance meaures supporting continuous improvement: Challenges and opportunities for manufacturing SMEs2016Conference paper (Refereed)
    Abstract [en]

    This paper provides a holistic view of visual communication of performance measures supporting continuous improvement in manufacturing SMEs. This is done by a theoretical part with a literature review, and an empirical part with case studies, including both the managers’ and the operators’ perspectives, and by focusing on manufacturing SMEs. The paper identifies five challenges and one opportunity in visual communication that SMEs perceive when using visual communication of performance measures, supporting continuous improvement.

45678910 301 - 350 of 633
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf