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  • 51.
    Andersson Granberg, Tobias
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Polishchuk, Tatiana
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Polishchuk, Valentin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Schmidt, Christiane
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    A framework for integrated terminal airspace design2019Ingår i: Aeronautical Journal, ISSN 0001-9240, Vol. 123, nr 1263, s. 567-585Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Route planning and airspace sectorisation are two central tasks in air traffic management. Traditionally, the routing and sectorisation problems were considered separately, with aircraft trajectories serving as input to the sectorisation problem and, reciprocally, sectors being part of the input to the path finding algorithms. In this paper we propose a simultaneous design of routes and sectors for a transition airspace. We compare two approaches for this integrated design: one based on mixed integer programming, and one Voronoi-based model that separates potential "hotspots" of controller activity resulting from the terminal routes. We apply our two approaches to the design of Stockholm Terminal Maneuvering Area.

  • 52.
    Andersson, Hans
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Företagsekonomi. Linköpings universitet, Filosofiska fakulteten.
    Berggren, ChristianLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Projekt, innovationer och entreprenörskap. Linköpings universitet, Tekniska fakulteten. University of Sussex.
    Kunskapsintegration och innovation i en internationaliserande ekonomi: Slutrapport från ett forskningsprogram2015Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
    Abstract [sv]

    Den här skriften presenterar ett urval resultat och texter från forskningsprogrammet ”Kunskapsintegration och innovation i en internationaliserande ekonomi” (Knowledge Integration and Innovation in Transnational Enterprise, KITE) som finansierats av Riksbankens Jubileumsfond i två faser under åren 2007–2015. I programmet har vi analyserat hur företag, speciellt i tekniktunga industrier, påverkas av den allt mer globala konkurrensen om nya produkter och tjänster, hur nya specialiserade kunskaper växer fram och tas tillvara, och hur de kan förenas med existerande kunskapsbas. I denna skrift finns studier på tre olika nivåer: branschnivån, med analyser av innovationsprocesser och kunskapsutmaningar i industriella sektorer; företagsnivån, med skildringar av förändringar i företagens interna organisering av kunskapsbildande processer och undersökningar av nya former för utbyte och samspel mellan företag; samt mikronivån, med undersökningar av samspelet mellan individuella specialister inom företag. Skriften vänder sig både till den intresserade allmänheten och till forskare med annan vetenskaplig bakgrund. Fokus är på internationellt konkurrerande branscher och företag, men analyserna av kunskapens delning och sammanflätning, separation och integration, har bäring också på andra kunskapsintensiva sektorer och verksamheter, från statliga verk till sjukvård.

    En vetenskaplig presentation av programmets forskning under de första fyra åren finns i boken Knowledge Integration and Innovation: Critical Challenges Facing International Technology-Based Firms (redigerad av Berggren, Bergek, Bengtsson, Hobday & Söderlund och utgiven av Oxford University Press 2011). En uppföljande volym, Managing Knowledge Integration Across Boundaries, planeras av samma förlag 2016 (redigerad av Tell, Berggren, Brusoni & Van de Ven). I den medverkar ett antal internationella författare vilket visar kunskapsområdets globala tyngd och intresse. Under programmets drygt åtta år har deltagarna publicerat ett mycket stort antal artiklar, konferensbidrag, bokkapitel och liknande. För dessa hänvisar vi till programmets hemsida www.liu.se/kite.

    Vi har under hela programperioden arbetat intensivt med att diskuteraoch konstruktivt kritisera och utveckla varandras bidrag. Därför har det varit naturligt att denna skrift inbegriper många programdeltagares medverkan. En presentation av samtliga medverkande finns i slutet av denna skrift. Följande KITE-forskare har medverkat i nedan angivna kapitel:

    Hans Andersson (kapitel 4)

    Lars Bengtsson (kapitel 7)

    Marie Bengtsson (kapitel 3)

    Anna Bergek (kapitel 2)

    Christian Berggren (kapitel 1)

    Karin Bredin (kapitel 6)

    Cecilia Enberg (kapitel 5, 7)

    Mattias Johansson (kapitel 4)

    Nicolette Lakemond (kapitel 7)

    Lars Lindkvist (kapitel 3)

    Thomas Magnusson (kapitel 1)

    Camilla Niss (kapitel 6)

    Jonas Söderlund (kapitel 6)

    Fredrik Tell (kapitel 5)

    Vi vill också tacka Jenny Björkman på Riksbankens Jubileumsfond och Makadam förlag för deras engagerade arbete med redigering och produktion av slutresultatet.

    Ladda ner fulltext (pdf)
    Kunskapsintegration och innovation i en internationaliserande ekonomi
  • 53.
    Andersson, Hans
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Företagsekonomi. Linköpings universitet, Filosofiska fakulteten.
    Berggren, Christian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Projekt, innovationer och entreprenörskap. Linköpings universitet, Tekniska högskolan.
    Leveraging inventors' creativity2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    While creativity is often understood as the generation of valuable novelty, we extend that view into a framework based on well-known and established models from the creativity literature. In addition to generation of novelty which forms our frameworks first dimension, we add selection of novelty, and type of creative contribution.  

    Based on interviews with inventors and managers in three large, patent-intensive firms, representing completely different industries, we show how the framework can be employed in order to better understand in what ways different practices exploit and/or support the inventors’ creative abilities. By relating the practices not to creativity in general but to components of creativity (c.f Amabile 1997) the paper enriches the discussion of how inventors’ can be leveraged in technology-based firms.

  • 54. Beställ onlineKöp publikationen >>
    Andersson, Henric
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Variability and Customization of Simulator Products: A Product Line Approach in Model Based Systems Engineering2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    FLYGPLANSTILLVERKARE LIKSOM andra industrier inom utveckling och tillverkning, hanterar ökande komplexitet i sina produkter och upplever en större konkurrens på den globala marknaden. Produkter byggs från allt mer avancerad teknologi. Ingående delar av mekanik, elektronik och mjukvara växer i antal och blir allt mer integrerade. Olika metoder används för att hantera information och kunskap om produkter i olika steg av dess livscykel.

    ”Återanvändning” och ”Modellbaserad utveckling” är två tydliga trender för att öka effektiviteten inom industriell utveckling. Produktfamiljer används för att minska ledtider när man skapar varianter av produkter genom att återanvända färdiga komponenter. Modellbaserade metoder ger möjlighet att tidigt i livscykeln samla kunskap om ett system för att användas under hela systemets livstid. De ger också strukturerad hantering av data som grund för analys, automatisering och samarbete mellan utvecklingsteam, vilket är en förutsättning för effektiv hantering av komplexa system och produkter.

    Detta arbete är fokuserat på en kombination av metoder och tekniker för;

    • utveckling som baseras på modellering och simulering, och
    • (åter)användning av simuleringsmodeller.

    Med ökande beräkningsprestanda och effektivare metoder/verktyg för att bygga simuleringsmodeller så ökar antalet modeller och deras användning spänner allt från konceptvärderingen till utbildning av slutanvändare. Arbetet med verifiering och validering av simuleringsmodeller utgör en stor del av deras totala utvecklings- och underhållskostnader. De studerade metoderna syftar till att minska antalet liknande modeller som hanteras av olika team för olika syften, som till exempel; utveckling, verifiering och som stöd för slutanvändare.

    Resultat av arbete inkluderar utvärdering av en konfigurator för att välja, integrera och anpassa simuleringsmodeller för olika typer av flygplanssimulatorer i en simulatorproduktfamilj. Dessutom bidrar arbetet med en metodik där begränsningarna i den primära produktfamiljen (flygplan) begränsar konfigurationsutrymmet för den sekundära produktfamiljen (simulatorer). Utvärdering av den föreslagna metoden har genomförts i samarbete med simulatoravdelning för flygplan 39 Gripen på Saab Aeronautics.

    Delarbeten
    1. Experience from introducing Unified Modeling Language/Systems Modeling Language at Saab Aerosystems
    Öppna denna publikation i ny flik eller fönster >>Experience from introducing Unified Modeling Language/Systems Modeling Language at Saab Aerosystems
    2010 (Engelska)Ingår i: Systems Engineering, ISSN 1098-1241, E-ISSN 1520-6858, Vol. 13, nr 4, s. 369-380Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A Unified Modeling Language/Systems Modeling Language (UML/SysML) subset was the modeling notation selected for an aerospace systems engineering project at Saab Aerosystems. In this paper, the rationale for selecting UML/SysML is given, along with a description of the situation at the project planning stage regarding business conditions, method and tools support. The usage of use case, sequence, and activity diagrams are described as well as definition of functional chains with SysML. Furthermore, the connections to system implementation activities including code generation and simulation are discussed. The advantages and disadvantages of using UML/SysML from experience in an industrial context are reported.

    It is also described how UML/SysML is related to industrial research projects in the Model Based Systems Engineering (MBSE) methods and tools area. Introducing UML/SysML with a methodology and a supporting toolset in an operative organization require a clear strategy, including planning, just-in-time training, and mentor support. Finally, industrial needs for further development of SysML are discussed.

    Ort, förlag, år, upplaga, sidor
    Wiley, 2010
    Nyckelord
    Systems Modeling Language, Unified Modeling Language, Model Based Systems Engineering, Unmanned Aerial Vehicle
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-17941 (URN)10.1002/sys.20156 (DOI)000284008700005 ()
    Tillgänglig från: 2009-04-27 Skapad: 2009-04-27 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    2. Model Based Systems Engineering for Aircraft Systems – How does Modelica Based Tools Fit?
    Öppna denna publikation i ny flik eller fönster >>Model Based Systems Engineering for Aircraft Systems – How does Modelica Based Tools Fit?
    2011 (Engelska)Ingår i: Proceedings of the 8th International Modelica Conference, March 20th-22nd, Technical Univeristy, Dresden, Germany / [ed] Clauß, Christoph, Linköping: Linköping University Electronic Press, 2011, s. 856-864Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    Abstract [en]

    Saab Aeronautics has chosen Modelica and Dymola as part of the means for model based system engineering (MBSE). This paper will point out why a considerable effort has been made to migrate models from other simulation tools to Dymola. The paper also shows how the models and tools are used, experiences gained from usage in an industrial context as well as some remaining trouble spots.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2011
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 63
    Nyckelord
    MBSE, Dymola, Aircraft simulation, Model integration, Modelica
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-73511 (URN)10.3384/ecp11063856 (DOI)978-91-7393-096-3 (ISBN)
    Konferens
    8th International Modelica Conference, March 20th-22nd, Technical Univeristy, Dresden, Germany
    Tillgänglig från: 2012-01-06 Skapad: 2012-01-06 Senast uppdaterad: 2018-02-20Bibliografiskt granskad
    3. Variability and Configuration Principles for Simulation Models in Product Line Development
    Öppna denna publikation i ny flik eller fönster >>Variability and Configuration Principles for Simulation Models in Product Line Development
    2010 (Engelska)Ingår i: Proceedings of the 7th European Systems Engineering Conference, EuSEC 2010: Systems Engineering & Innovation / [ed] INCOSE, 2010, s. 15-Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    Abstract [en]

    This paper defines the challenges and needs related to Configuration Management of large scale aeronautical simulation systems, where the MBSE approach is a guiding force. The basic problem is to support modeling and simulation of all variants of a product line. The simulation models may be used in (at least) three different contexts; development, verification and training, each with their specific objectives.

    Assumptions and basic components of the research issue are as follows: There exists a defined product line. The product line is modeled with respect of

    • Configuration; for certification, delivery, and maintenance in a PDM/PLM context
    • Behavior; for development, verification and training in a simulation context

    Configurable simulation models are developed and maintained to represent parts/modules of the product line as well as the environment where the products operate. Each simulation model included in any utilized simulation system can be viewed as a module in a (simulation product) platform. The modular models are stored in a model library for easy access and inclusion in a simulation system. Every model must be configurable in at least three dimensions; representation, usage and implementation. They will represent a specific product within the product family, they will be used in some of the three contexts (development, verification and training) and they will be implemented in a specific simulation platform/architecture.

    Management of configurable simulation models in the described context is an increasingly challenging activity. Supporting systems and methods for configuration and integration of models and simulation systems are not mature and do not scale up. To view the model set as a Software Product Line representing the Product Line of the end products is an approach to more stringent map the simulation models to the real product/system. A concept of a structured ConfiguratioN datA object (CNA-string) is introduced as a means to integrate configuration information and to be used for simulation set-up purposes. Application example in the work is the light weight fighter aircraft Saab 39 Gripen.

    Nyckelord
    MBSE, PDM, PLM, CSM, Simulation
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-60818 (URN)
    Konferens
    7th European Systems Engineering Conference EuSEC 2010. Systems Engineering and Innovation, Stockholm, Sweden, May 23–26
    Tillgänglig från: 2010-10-27 Skapad: 2010-10-27 Senast uppdaterad: 2012-02-16Bibliografiskt granskad
    4. Configuration Management of Models for Aircraft Simulation
    Öppna denna publikation i ny flik eller fönster >>Configuration Management of Models for Aircraft Simulation
    2010 (Engelska)Ingår i: Proceedings of the 27th International Congress of the Aeronautical Sciences, 2010, s. 10-Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    Abstract [en]

    Support for configuration and instantiation of large-scale aircraft simulations has become a major issue as the numbers of models grow, model fidelity increases and there is a trend to design models to allow reuse between simulation environments. In this work a method for configuration support is presented that is based on the Product Line principles with structures and data inherited from the Product Data Management system. An XML-based information object to carry product configuration data and knowledge between tools, called a CNA-string is introduced. A rule-based method to support specification of consistent configurations is adopted from the sales configuration domain. The application example is configurations of the Gripen fighter aircraft simulation models.

    Nyckelord
    Software Product Line, Modularity, Configurator, Simulation
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-60821 (URN)
    Konferens
    The 27th International Congress of the Aeronautical Sciences, 19-24 September, Nice, France
    Tillgänglig från: 2010-10-27 Skapad: 2010-10-27 Senast uppdaterad: 2012-02-16Bibliografiskt granskad
    5. Methodology for Development and Validation of Multipurpose Simulation Models
    Öppna denna publikation i ny flik eller fönster >>Methodology for Development and Validation of Multipurpose Simulation Models
    2012 (Engelska)Ingår i: 50th AIAA Aerospace Sciences Meeting Online Proceedings including the New Horizons Forum and Aerospace Exposition (2012), AIAA , 2012Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper describes a framework for development and validation of multipurpose simulation models. The presented methodology enables reuse of models in different applications with different purposes. The scope is simulation models representing physical environment, physical aircraft systems or subsystems, avionics equipment, and electronic hardware. The methodology has been developed by a small interdisciplinary team, with experience from Modeling and Simulation (M&S) of vehicle systems as well as development of simulators for verification and training. Special care has been taken to ensure usability of the workflow and method descriptions, mainly by means of 1) a user friendly format, easy to overview and update, 2) keeping the amount of text down, and 3) providing relevant examples, templates, and checklists. A simulation model of the Environmental Control System (ECS) of a military fighter aircraft, the Saab Gripen, is used as an example to guide the reader through the workflow of developing and validating multipurpose simulation models. The methods described in the paper can be used in both military and civil applications, and are not limited to the aircraft industry.

    Ort, förlag, år, upplaga, sidor
    AIAA, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-74716 (URN)10.2514/6.2012-877 (DOI)
    Konferens
    50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 9–12 January, 2012, Gaylord Opryland Resort & Convention Center, 9-12 January, Nashville, Tennessee
    Tillgänglig från: 2012-02-06 Skapad: 2012-02-06 Senast uppdaterad: 2016-04-25
    6. Towards Configuration Support for Collaborative Simulator Development: A Product Line Approach in Model Based Systems Engineering
    Öppna denna publikation i ny flik eller fönster >>Towards Configuration Support for Collaborative Simulator Development: A Product Line Approach in Model Based Systems Engineering
    2011 (Engelska)Ingår i: Proceedings of the 2011 20th IEEE International Workshops on Enabling Technologies, WETICE 2011: Infrastructure for Collaborative Enterprises, IEEE conference proceedings, 2011, s. 185-192Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    Abstract [en]

    In development and support of complex products such as power plants, automotive vehicles, or aircrafts, modeling and simulation has become an important activity as a basis for knowledge capture. Simulation is used in several steps of the product lifecycle; for evaluation of early design, for system verification, and for user training. With emerging techniques such as tools for high-level modeling, multi-core computing, and visualization, the number of useful models is growing. This paper focuses on reuse of multipurpose models and configuration support in a product line context. A configurator prototype system is presented. The simulator set created from validated models is considered to be a secondary product line. The product set which the simulation models represent is considered to be the primary product line. The Saab Gripen fighter aircraft, together with simulators in which the aircraft behavior, performance, and handling qualities are represented, is used to exemplify application. Integration principles of the systems for simulator configuration, Software Configuration Management, and Product Data Management (PDM) are studied. Preliminary results show that a configurator tool can be used, but there is need to map structures between the simulation and PDM domains.

    Ort, förlag, år, upplaga, sidor
    IEEE conference proceedings, 2011
    Nyckelord
    MBSE, Product Line, Configurator, Simulation
    Nationell ämneskategori
    Data- och informationsvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-70177 (URN)10.1109/WETICE.2011.74 (DOI)2-s2.0-80052639762 (Scopus ID)978-0-7695-4410-6 (ISBN)978-1-4577-0134-4 (ISBN)
    Konferens
    20th IEEE International Workshops on Enabling Technologies: Infrastructures for Collaborative Enterprises, 27-29 June, Paris, France
    Tillgänglig från: 2011-08-23 Skapad: 2011-08-23 Senast uppdaterad: 2018-01-12Bibliografiskt granskad
    7. Experience from Model and Software Reuse in Aircraft Simulator Product Line Engineering
    Öppna denna publikation i ny flik eller fönster >>Experience from Model and Software Reuse in Aircraft Simulator Product Line Engineering
    2013 (Engelska)Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 55, nr 3, s. 595-606Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Context: "Reuse" and "Model Based Development" are two prominent trends for improving industrial development efficiency. Product lines are used to reduce the time to create product variants by reusing components. The model based approach provides the opportunity to enhance knowledge capture for a system in the early stages in order to be reused throughout its lifecycle. This paper describes how these two trends are combined to support development and support of a simulator product line for the SAAB 39 Gripen fighter aircraft.

    Objective: The work aims at improving the support (in terms of efficiency and quality) when creating simulation model configurations. The objective is to increase the level of reuse when combining and customizing models for usage in a range of development and training simulators.

    Method: The research has been conducted with an interactive approach using prototyping and demonstrations, and the evaluation is based on an iterative and a retrospective method.

    Results: A product line of simulator models for the SAAB 39 Gripen aircraft has been analyzed and defined in a Product Variant Master. A configurator system has been implemented for creation, integration, and customization of stringent simulator model configurations. The system is currently under incorporation in the standard development process at SAAB Aeronautics.

    Conclusion: The explicit and visual description of products and their variability through a configurator system enables better insights and a common understanding so that collaboration on possible product configurations improves and the potential of software reuse increases. The combination of application fields imposes constraints on how traditional tools and methods may be utilized. Solutions for Design Automation and Knowledge Based Engineering are available, but their application has limitations for Software Product Line engineering and the reuse of simulation models.

    Nyckelord
    Software Product Line; SPL; Knowledge Based Engineering; KBE; Model Based Development; Simulation; Configurator; Customization; PDM; SCM
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-75077 (URN)10.1016/j.infsof.2012.06.014 (DOI)000315369200008 ()
    Tillgänglig från: 2012-02-16 Skapad: 2012-02-16 Senast uppdaterad: 2017-12-07
    Ladda ner fulltext (pdf)
    Variability and Customization of Simulator Products: A Product Line Approach in Model Based Systems Engineering
    Ladda ner (pdf)
    omslag
  • 55.
    Andersson, Henric
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Herzog, Erik
    Saab Aeronautics, Linköping, Sweden.
    Ölvander, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Experience from Model and Software Reuse in Aircraft Simulator Product Line Engineering2013Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 55, nr 3, s. 595-606Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context: "Reuse" and "Model Based Development" are two prominent trends for improving industrial development efficiency. Product lines are used to reduce the time to create product variants by reusing components. The model based approach provides the opportunity to enhance knowledge capture for a system in the early stages in order to be reused throughout its lifecycle. This paper describes how these two trends are combined to support development and support of a simulator product line for the SAAB 39 Gripen fighter aircraft.

    Objective: The work aims at improving the support (in terms of efficiency and quality) when creating simulation model configurations. The objective is to increase the level of reuse when combining and customizing models for usage in a range of development and training simulators.

    Method: The research has been conducted with an interactive approach using prototyping and demonstrations, and the evaluation is based on an iterative and a retrospective method.

    Results: A product line of simulator models for the SAAB 39 Gripen aircraft has been analyzed and defined in a Product Variant Master. A configurator system has been implemented for creation, integration, and customization of stringent simulator model configurations. The system is currently under incorporation in the standard development process at SAAB Aeronautics.

    Conclusion: The explicit and visual description of products and their variability through a configurator system enables better insights and a common understanding so that collaboration on possible product configurations improves and the potential of software reuse increases. The combination of application fields imposes constraints on how traditional tools and methods may be utilized. Solutions for Design Automation and Knowledge Based Engineering are available, but their application has limitations for Software Product Line engineering and the reuse of simulation models.

  • 56. Beställ onlineKöp publikationen >>
    Andersson, Håkan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    A Co-Simulation Approach for Hydraulic Percussion Units2018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This Licentiate of Engineering thesis concerns modelling and simulation of hydraulic percussion units. These units are often found in equipment for breaking or drilling in rock and concrete, and are also often driven by oil hydraulics, in which complex fluid-structure couplings are essential for their operation.

    Current methodologies used today when developing hydraulic percussion units are based on decoupled analyses, which are not correctly capturing the important coupled mechanisms. Hence, an efficient method for coupled simulations is of high importance, since these mechanisms are critical for the function of these units. Therefore, a co-simulation approach between a 1D system simulation model representing the fluid system and a structural 3D FE-model is proposed.

    This approach is presented in detail, implemented for two well-known simulation tools and evaluated for a simple but relevant model. The Hopsan simulation tool was used for the fluid system and the FE-simulation software LS-DYNA was used for the structural mechanics simulation. The co-simulation interface was implemented using the Functional Mock-up Interface-standard.

    The approach was further developed to also incorporate multiple components for coupled simulations. This was considered necessary when models for the real application are to be developed. The use of two components for co-simulation was successfully evaluated for two models, one using the simple rigid body representation, and a second where linear elastic representations of the structural material were implemented.

    An experimental validation of the co-simulation approach applied to an existing hydraulic hammer was performed. Experiments on the hydraulic hammer were performed using an in-house test rig, and responses were registered at four different running conditions. The co-simulation model was developed using the same approach as before. The corresponding running conditions were simulated and the responses were successfully validated against the experiments. A parameter study was also performed involving two design parameters with the objective to evaluate the effects of a parameter change.

    This thesis consists of two parts, where Part I gives an introduction to the application, the simulation method and the implementation, while Part II consists of three papers from this project.

    Delarbeten
    1. A co-simulation method for system-level simulation of fluid-structure couplings in hydraulic percussion units
    Öppna denna publikation i ny flik eller fönster >>A co-simulation method for system-level simulation of fluid-structure couplings in hydraulic percussion units
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    2017 (Engelska)Ingår i: Engineering with Computers, ISSN 0177-0667, E-ISSN 1435-5663, Vol. 33, nr 2, s. 317-333Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This paper addresses a co-simulation method for fluid power driven machinery equipment, i.e. oil hydraulic machinery. In these types of machinery, the fluid-structure interaction affects the end-product performance to a large extent, hence an efficient co-simulation method is of high importance. The proposed method is based on a 1D system model representing the fluid components of the hydraulic machinery, within which structural 3D Finite Element (FE) models can be incorporated for detailed simulation of specific sub-models or complete structural assemblies. This means that the fluid system simulation will get a more accurate structural response, and that the structural simulation will get more correct fluid loads at every time step, compared to decoupled analysis. Global system parameters such as fluid flow, performance and efficiency can be evaluated from the 1D system model simulation results. From the 3D FE-models, it is possible to evaluate displacements, stresses and strains to be used in stress analysis, fatigue evaluation, acoustic analysis, etc. The method has been implemented using two well-known simulation tools for fluid power system simulations and FE-simulations, respectively, where the interface between the tools is realised by use of the Functional Mock-up Interface standard. A simple but relevant model is used to validate the method.

    Ort, förlag, år, upplaga, sidor
    SPRINGER, 2017
    Nyckelord
    Co-simulation; Fluid-structure coupling; System simulation; Functional mock-up interface; Fluid power machinery; Transmission line modelling
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:liu:diva-136875 (URN)10.1007/s00366-016-0476-8 (DOI)000398468100012 ()
    Anmärkning

    Funding Agencies|Atlas Copco Construction Tools

    Tillgänglig från: 2017-04-30 Skapad: 2017-04-30 Senast uppdaterad: 2018-09-11
    2. System level co-simulation of a control valve and hydraulic cylinder circuit in a hydraulic percussion unit
    Öppna denna publikation i ny flik eller fönster >>System level co-simulation of a control valve and hydraulic cylinder circuit in a hydraulic percussion unit
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    2017 (Engelska)Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Ericson and Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 225-235Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    In this study a previously developed co-simulation method that is based on a 1D system model representing the fluid components of a hydraulic machinery, within which structural 3D Finite Element (FE) models can be incorporated for detailed simulation of specific sub-models or complete structural assemblies, is further developed. The fluid system model consists of ordinary differential equation sub-models that are computationally very inexpensive, but still represents the fluid dynamics very well. The co-simulation method has been shown to work very well for a simple model representing a hydraulic driven machinery. A more complex model was set up in this work, in which two cylinders in the hydraulic circuit were evaluated. Such type of models, including both the main piston and control valves, are necessary as they represent the real application to a further extent than the simple model, of only one cylinder. Two models have been developed and evaluated, from the simple rigid body representation of the structural mechanics model, to the more complex model using linear elastic representation. The 3D FE-model facilitates evaluation of displacements, stresses, and strains on a local level of the model. The results can be utilised for fatigue assessment, wear analysis and for predictions of noise radiation.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2017
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 144
    Nyckelord
    Co-simulation, Fluid-structure coupling, System simulation, Functional mockup interface, Fluid power machinery, Transmission line modelling
    Nationell ämneskategori
    Teknisk mekanik Farkostteknik Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-151015 (URN)10.3384/ecp17144225 (DOI)9789176853696 (ISBN)
    Konferens
    15th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden
    Tillgänglig från: 2018-09-11 Skapad: 2018-09-11 Senast uppdaterad: 2018-09-11Bibliografiskt granskad
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    A Co-Simulation Approach for Hydraulic Percussion Units
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  • 57.
    Andersson, Håkan
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten. Epiroc, Sweden.
    Simonsson, Kjell
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Hilding, D.
    Dynamore Nord AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Schill, M.
    Dynamore Nord AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Sigfridsson, E.
    Epiroc, Sweden.
    Leidermark, Daniel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Validation of a co-simulation approach for hydraulic percussion units applied to a hydraulic hammer2019Ingår i: Advances in Engineering Software, ISSN 0965-9978, E-ISSN 1873-5339, Vol. 131, s. 102-115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, a previously developed co-simulation approach has been adopted to simulate the responses of an existing hydraulic hammer product. This approach is based on a 1D system model representing the fluid components and a 3D finite element model representing the structural parts of the hydraulic hammer. The simulation model was validated against four experiments with different running conditions. The corresponding set-ups were analysed using the co-simulation method in order to evaluate the overall responses. A parameter study was also performed involving the working pressure and the restrictor diameter, with the objective to validate that a parameter change in the simulation model will affect the input and output power in the same direction as in the experiments. The experimental responses used in the validation were time history data of fluid pressure, component position and acceleration, and structural stresses. The experiments result in high frequency and high amplitude excitations of the hydraulic hammer and thus require a model with a high resolution of the model dynamics. The conclusion of the validation is that the simulation model is able to replicate the experimental responses with high accuracy including the high frequency dynamics. The favourable outcome of the validation makes the described co-simulation approach promising as an efficient tool for a wide range of other applications where short time duration mechanisms need to be studied.

  • 58.
    Andersson, Håkan
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Simonsson, Kjell
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Hilding, Daniel
    DYNAmore Nordic AB, Brigadgatan 5, 587 58 Linköping, Sweden.
    Schill, Mikael
    DYNAmore Nordic AB, Brigadgatan 5, 587 58 Linköping, Sweden.
    Leidermark, Daniel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    System level co-simulation of a control valve and hydraulic cylinder circuit in a hydraulic percussion unit2017Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Ericson and Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 225-235Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this study a previously developed co-simulation method that is based on a 1D system model representing the fluid components of a hydraulic machinery, within which structural 3D Finite Element (FE) models can be incorporated for detailed simulation of specific sub-models or complete structural assemblies, is further developed. The fluid system model consists of ordinary differential equation sub-models that are computationally very inexpensive, but still represents the fluid dynamics very well. The co-simulation method has been shown to work very well for a simple model representing a hydraulic driven machinery. A more complex model was set up in this work, in which two cylinders in the hydraulic circuit were evaluated. Such type of models, including both the main piston and control valves, are necessary as they represent the real application to a further extent than the simple model, of only one cylinder. Two models have been developed and evaluated, from the simple rigid body representation of the structural mechanics model, to the more complex model using linear elastic representation. The 3D FE-model facilitates evaluation of displacements, stresses, and strains on a local level of the model. The results can be utilised for fatigue assessment, wear analysis and for predictions of noise radiation.

    Ladda ner fulltext (pdf)
    System level co-simulation of a control valve and hydraulic cylinder circuit in a hydraulic percussion unit
  • 59.
    Andersson, Jim
    et al.
    Luleå University of Technology, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Sweden.
    Malek, Laura
    Lund University, Sweden.
    Hultegren, Christian
    Lund University, Sweden.
    Pettersson, Karin
    Chalmers University of Technology, Gothenburg, Sweden.
    Wetterlund, Elisabeth
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    System studies on biofuel production via integrated biomass gasification2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A large number of national and international techno-economic studies on industrially integrated gasifiers for production of biofuels have been published during the recent years. These studies comprise different types of gasifiers (fluidized bed, indirect and entrained flow) integrated in different industries for the production of various types of chemicals and transportation fuels (SNG, FT-products, methanol, DME etc.) The results are often used for techno-economic comparisons between different biorefinery concepts. One relatively common observation is that even if the applied technology and the produced biofuel are the same, the results of the techno-economic studies may differ significantly.

    The main objective of this project has been to perform a comprehensive review of publications regarding industrially integrated biomass gasifiers for motor fuel production. The purposes have been to identify and highlight the main reasons why similar studies differ considerably and to prepare a basis for “fair” techno-economic comparisons. Another objective has been to identify possible lack of industrial integration studies that may be of interest to carry out in a second phase of the project.

    Around 40 national and international reports and articles have been analysed and reviewed. The majority of the studies concern gasifiers installed in chemical pulp and paper mills where black liquor gasification is the dominating technology. District heating systems are also well represented. Only a few studies have been found with mechanical pulp and paper mills, steel industries and the oil refineries as case basis. Other industries have rarely, or not at all, been considered for industrial integration studies. Surprisingly, no studies regarding integration of biomass gasification neither in saw mills nor in wood pellet production industry have been found.

    There are several reasons why the results of the reviewed techno-economic studies vary. Some examples are that different system boundaries have been set and that different technical and economic assumptions have been made, product yields and energy efficiencies may be calculated using different methods etc. For obvious reasons, the studies are not made in the same year, which means that different monetary exchange rates and indices have been applied. It is therefore very difficult, and sometimes even impossible, to compare the technical as well as the economic results from the different studies. When technical evaluations are to be carried out, there is no general method for how to set the system boundaries and no right or wrong way to calculate the system efficiencies as long as the boundaries and methods are transparent and clearly described. This also means that it becomes fruitless to compare efficiencies between different concepts unless the comparison is done on an exactly equal basis.

    However, even on an equal basis, a comparison is not a straight forward process. For example, calculated efficiencies may be based on the marginal supply, which then become very dependent on how the industries exploit their resources before the integration. The resulting efficiencies are therefore very site-dependent. Increasing the system boundaries to include all in- and outgoing energy carriers from the main industry, as well as the integrated gasification plant (i.e. total plant mass and energy balance), would inflict the same site-dependency problem. The resulting system efficiency is therefore a measure of the potential improvement that a specific industry could achieve by integrating a biomass gasification concept.

    When estimating the overall system efficiency of industrial biorefinery concepts that include multiple types of product flows and energy sources, the authors of this report encourage the use of electrical equivalents as a measure of the overall system efficiency. This should be done in order to take the energy quality of different energy carriers into concern.

    In the published economic evaluations, it has been found that there is a large number of studies containing both integration and production cost estimates. However, the number of references for the cost data is rather limited. The majority of these have also been published by the same group of people and use the same or similar background information. The information in these references is based on quotes and estimates, which is good, however none of these are publically available and therefore difficult to value with respect to content and accuracy.

    It has further been found that the variance in the operational costs is quite significant. Something that is particularly true for biomass costs, which have a high variance. This may be explained by natural variations in the quality of biomass used, but also to the different markets studied and the dates when the studies were performed. It may be seen from the specific investment costs that there is a significant spread in the data. It may also be seen that the differences in capital employed and process yields will result in quite large variations in the production cost of the synthetic fuels. On a general note, the studies performed are considering future plants and in some cases assumes technology development. It is therefore relevant to question the use of today’s prices of utilities and feedstock’s. It is believed that it would be more representative to perform some kind of scenario analysis using different parameters resulting in different cost assumptions to better exemplify possible futures.

    Due to the surprising lack of reports and articles regarding integration of biomass gasifiers in sawmills, it would be of great interest to carry out such a study. Also larger scale wood pellet production plants could be of interest as a potential gasification based biorefinery.

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  • 60.
    Andersson, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling.
    An evaluation of the FE-model adopted for modal analysis in the fan booster spool project, GEnx.2008Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    Avsikten med denna avhandling är att utvärdera den FE-modell som använts i modalanalyser av komponenten fan booster spool, framtagen och tillverkad av Volvo Aero Corporation, Trollhättan. Detaljen ingår i den civila flygplansmotorn GEnx som är utvecklad för flygplanet Boeing 787 Dreamliner.

    Inledande tester av spolen påvisade en mycket god korrelation mellan analys och test men när spolen senare provkördes i en komplett monterad motor noterades en uppenbar skillnad i resultat. Den andra noddiameterns egenfrekvenser indikerade att spolen i test hade ett något styvare beteende än vad som beräknats i analys.

    En teori utvecklades som byggde på att en initiell kontakt mellan rotor och ett slitskikt på statorn kunde framkalla en förstyvande effekt på spolen när rotorn på grund av rotationslaster expanderar radiellt. Detta examensarbete initierades då för att undersöka om denna kontakt kunde inkluderas i FE-modellen och för att utreda om kontakten har en möjlighet att förstyva spolen.

    Avhandlingen utvärderar FE-modellen med avseende på randvillkor, laster och modelleringsteknik i FE-programmet Ansys 10.0. En grundlig kartläggning av spolens känslighet påvisar en robust komponent med hög motståndskraft mot yttre och inre störningar.

    En förstyvande effekt relaterad till en initiell kontakt mellan slitskikt och spole bekräftas i denna avhandling. Kontakten har visat sig ha särskild inverkan på den andra noddiametern och dess egenfrekvenser. Ett förslag på modelleringsteknik där den förstyvande effekten inkluderas har däremot inte föreslagits i detta arbete då effekten enligt uppgift går förlorad efter en inkörningsperiod.

    Det har i detta arbete visats att det kommando som i Ansys tidigare använts för att kompensera för så kallade spin softening-effekter, kspin, resulterar i konservativa värden för spolens egenfrekvenser. En rekommendation baserad på de resultat som framkommit är därför att utesluta funktionen kspin i modalanalyser för denna komponent. Valet av sektorstorlek och kopplingsmetod mellan masselement och spole har också visats ha en tydlig inverkan på de beräknade egenfrekvenserna.

    Spolens radiella förskjutningar har analyserats som funktion av rotationshastigheten. Resultatet visar att den hastighet då kontakt mellan tätningständer och spole etableras är nästintill identisk med den hastighet då töjningar först börjar uppträda i spolen enligt testdata från töjningsgivarprov.

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  • 61.
    Andersson, Johan
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Wyckman, Oscar
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Modeling of Fuel Dynamics in a Small Two-Stroke Engine Crankcase2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    För alla tvåtaktsmotorer med bränslematning genom vevhuset är bränsledynamiken svårpredikterad. Detta beror på att bränslet måste passera vevhusvolymen innan det når förbränningskammaren. Denna uppsats handlar om utveckling av en modell som ger realistisk dynamik för bränslet i tvåtaktsmotorers vevhus.

    Vevhusmodellen i denna uppsats har två delar. Den ena delen är en modell för bränslefilm på motorväggar och den andra delen är en modell för koncentration av förångat bränsle i vevhusvolymen. Bränslefilmsmodellen har två parametrar som måste trimmas. Den ena är andelen bränsle från förgasaren som inte förångas direkt och den andra är tidsåtgången för förångning av bränslefilmen.

    Uppsatsen behandlar trimning av dessa parametrar genom körning av modellen med indata från mätningar. Eftersom inte all indata kan mätas behövs även modeller för dessa. Därför behandlar uppsatsen även utveckling av enkla modeller för luftflöde, bränsleflöde, gasblandning i avgasvolymen och beteende hos den för mätningar använda λ-sonden.

    Parameterestimeringen för vevhusmodellen som är gjord i denna uppsats resulterar i parametrar som svarar mot konstant andel av bränslet från förgasaren som förångas direkt och en förångningshastighet för bränslefilmen som ökar med ökande motorhastighet. Parameterestimeringen är gjord med mätdata från normal körning vid tre olika motorhastigheter. Giltigheten för modellen är begränsad till dessa hastigheter och kan inte appliceras på körning av motorn vid kallstart.

    Modellen är körd och jämförd med valideringsdata från olika körfall. Modellen förutser dynamiska beteenden väl, men har ett systematiskt fel gällande medelvärdet på λ. Eftersom detta medelvärde beror på förhållandet mellan luftflöde och bränsleflöde in i vevhuset är sannolikt detta systematiska fel en effekt av osäkerhet i de enkla modeller som utvecklats för dessa flöden.

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  • 62.
    Andersson, Jonas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Hydrauliskt säkerhetsblock: Hur ett ventilblock konstrueras upp till PLe enligt ISO 138492019Självständigt arbete på grundnivå (högskoleexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Detta arbete har gjorts i samarbete med Camatec Industriteknik AB som önskade att undersöka hur man kan tillverka hydrauliska ventilblock, så kallade säkerhetsblock, enligt ISO 13849 och PL-skalan. Då denna standard implementeras allt mer i allt från industrimaskiner till mobilhydraulik vill man tidigt undersöka möjligheterna att saluföra ventilblock enligt denna standard. Arbetet pågick under en period på 10 veckor och utfördes på LiU (Linköpings Universitet) samt Camatecs kontor i Karlstad. Man började med att ta reda på huruvida en konstruktion kunde uppfylla PL-skalan som definierades i ISO 13849 och hur detta då skulle realiseras. En kravspecifikation sammanställdes utifrån de krav som berörde själva blocket. Ett befintligt konceptförslag itererades och låg till grund för en beräkningsmodell. Med ett preliminärt spänningsfall hittades ett antal material utifrån rekommendationer och databaser som uppfyllde de satta kraven. Materialen viktades i en viktningsmatris och två slutgiltiga material kunde bestämmas. Ett slutgiltigt koncept gjordes där man utförde en utmattningsanalys med de valda materialen. När materialval, konstruktion och beräkning var klart skapades ett ritningsunderlag som kom att användas för tillverkningsofferter. Resultatet blev en konstruktion med två olika materialförslag. Den ena versionen är konstruerad för ett MTTFD-värde på 150 år och den andra är konstruerad för ett MTTFD-värde på oändligheten. Beroende på ett systems övriga komponenter och struktur är dessa säkerhetsblock kompatibla upp till PLe, den högsta nivån i skalan. Vid en implementering av detta säkerhetsblock måste övriga delar av systemet uppfylla ställda krav, det rekommenderas att man noga följer utvecklingen kring ISO 13849 även i framtiden.

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  • 63.
    Andersson, Kent
    et al.
    Försvarshögskolan, Militärtekniska avdelningen (MTA), Stockholm, Sweden.
    Bang, Martin
    Försvarshögskolan, Militärtekniska avdelningen (MTA), Stockholm, Sweden.
    Marcus, Carina
    SAAB Aerosystems.
    Persson, Björn
    Försvarshögskolan, Militärtekniska avdelningen (MTA), Stockholm, Sweden.
    Sturesson, Peter
    Försvarshögskolan, Militärtekniska avdelningen (MTA), Stockholm, Sweden.
    Jensen, Eva
    Försvarshögskolan, Militärtekniska avdelningen (MTA), Stockholm, Sweden.
    Hult, Gunnar
    Försvarshögskolan, Militärtekniska avdelningen (MTA), Stockholm, Sweden.
    Military utility: A proposed concept to support decision-making2015Ingår i: Technology in society, ISSN 0160-791X, E-ISSN 1879-3274, Vol. 43, s. 23-32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A concept called Military Utility is proposed for the study of the use of technology in military operations. The proposed concept includes a three-level structure representing key features and their detailed components. On basic level the Military Utility of a technical system, to a military actor, in a specific context, is a compound measure of the military effectiveness, of the assessed technical system's suitability to the military capability system and of the affordability. The concept is derived through conceptual analysis and is based on related concepts used in social sciences, the military domain and Systems Engineering. It is argued that the concept has qualitative explanatory powers and can support military decision-making regarding technology in forecasts, defense planning, development, utilization and the lessons learned process. The suggested concept is expected to contribute to the development of the science of Military-Technology and to be found useful to actors related to defense.

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    FULLTEXT01
  • 64.
    Andersson, Kim
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling.
    de Ridder, Henk
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling.
    Förbättring av slangtillverkningen på BT : En produktionsteknisk studie2008Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    BT Products avdelning för slangtillverkning har i dagsläget problem med att klara av dagens produktionstakt. Målet med detta arbete är att identifiera och komma till rätta med dagens problem samt förbereda avdelningen inför en taktökning från dagens 50 000 till 60 000 truckar per år.

    I arbetets första skede gjordes en beskrivning av nuläget. Detta genom att observera och aktivt delta i arbete på avdelningen, intervjua personal, samla in data och göra en tidsstudie. Med resultatet av tidsstudien och datainsamlingen gjordes en beräkning av hur mycket tid som behövs för att hinna med dagens produktionstakt. Beräkningen visade att drygt hälften av den tillgängliga tiden borde räcka för att klara denna och att maskinernas kapacitet gott och väl räcker till. De problem som identifierats som orsak till att produktionen ändå inte hinns med är främst dålig layout, ineffektiva arbetssätt, onödiga arbetsmoment samt planeringsproblem kopplat till eftersläpning i produktionen.

    För att åtgärda dessa problem och förbereda slangavdelningen för en 60 000 takt har en rad förbättringsförslag arbetats fram. Ett förslag på en ny layout har gjorts för att uppnå ett bättre flöde i produktionen med mindre transporter och färre onödiga förflyttningar. Ett införande av standardiserat arbete bör göras för att säkerställa att alltid det mest effektiva arbetssättet används. Fler maskiner behöver inte införskaffas för att klara av produktionen, om de inte köps in i syfte att användas som säkerhetskapacitet, men en del hjälputrustning bör införskaffas för att underlätta och förbättra arbetet på avdelningen. Exempel på detta är en bättre slangvinda, streckkodläsare och monteringsutrustning.

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  • 65.
    Andersson, Lars Mattias
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Topics in color measurement2004Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Color characterizations of printing situations are essential for a correct color reproduction. To obtain a good color characterization, knowledge about the substrate, the printing process and the printer function are all of great importance. In this thesis, methods for color characterization of printing situations are proposed and the problems associated with the transfer of color characterization methods from spectrophotometers to flatbed scanners are extensively studied. All methods have been developed with bearing on digital printing technologies, although they can be applied to any printing system. Special emphasis has been put on the influence of paper properties in printing situations and image capturing of printed substrates.

  • 66.
    Andersson, Leila
    et al.
    Linköpings universitet, Institutionen för beteendevetenskap.
    Ortiz, Linda
    Linköpings universitet, Institutionen för beteendevetenskap.
    55+ - äldre anställdas föreställningar om att arbeta till pensionsålder och deras upplevelser av ett friskvårdsprojekt2005Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats
    Abstract [sv]

    Studien har genomförts på ett stålföretag som startade friskvårdsprojektet 55+ för anställda som är 55 år eller äldre. Syftet med denna studie är att få en bild över vad äldre anställda har för föreställningar om att arbeta till 65 och diskutera hur friskvårdsprojektet 55+ kan påverka deras förutsättningar att vara kvar i arbete till pensionsålder. I studien användes kvalitativ intervju som metod och undersökningsgruppen bestod av tio anställda på företaget.

    Förutsättningar som de intervjuade tog upp för att arbeta kvar rörde arbetet, hälsan, tajming med partner och ekonomin och många upplevde att de inte skulle kunna arbeta till 65 som de gör idag. Det fanns en besvikelse över att företaget inte längre erbjöd avtalspension i samma utsträckning som tidigare, eftersom de intervjuade mentalt hade förberett sig inför en pensionärstillvaro. Att de intervjuade från början inte var inställda på att arbeta till 65 kan ha påverkat deras upplevda förutsättningar i arbetet. De ställde dock om sina förväntningar och genom jämförelser med andra, såsom utländska kollegor, fann de sig i situationen. En osäkerhet över vad som gäller med pension fanns bland de intervjuade. Friskvårdprojektet kan ha fungerat hälsofrämjande, eftersom det för de intervjuade bidrog till ökad medvetenhet om hälsan. Det enligt oss största bidraget med friskvårdsprojektet var att deltagarna kände välbefinnande i att företaget satsade på just dem. Ett friskvårdprojekt kan därmed leda till ökad motivation hos äldre anställda att arbeta kvar till 65, men eftersom de intervjuade fortfarande upplevde hinder i arbetet skulle insatser även i arbetet kunna öka deras möjligheter och vilja att arbeta till 65.

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  • 67.
    Andersson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska fakulteten.
    Ebbers, Tino
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Fysiologiska kliniken US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Characterization and estimation of turbulence-related wall shear stress in patient-specific pulsatile blood flow2019Ingår i: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 85, s. 108-117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Disturbed, turbulent-like blood flow promotes chaotic wall shear stress (WSS) environments, impairing essential endothelial functions and increasing the susceptibility and progression of vascular diseases. These flow characteristics are today frequently detected at various anatomical, lesion and intervention-related sites, while their role as a pathological determinant is less understood. To present-day, numerous WSS-based descriptors have been proposed to characterize the spatiotemporal nature of the WSS disturbances, however, without differentiation between physiological laminar oscillations and turbulence-related WSS (tWSS) fluctuations. Also, much attention has been focused on magnetic resonance (MR) WSS estimations, so far with limited success; promoting the need of a near-wall surrogate marker. In this study, a new approach is explored to characterize the tWSS, by taking advantage of the tensor characteristics of the fluctuating WSS correlations, providing both a magnitude and an anisotropy measure of the disturbances. These parameters were studied in two patient-specific coarctation models (sever and mild), using large eddy simulations, and correlated against near-wall reciprocal Reynolds stress parameters. Collectively, results showed distinct regions of differing tWSS characteristics, features which were sensitive to changes in flow conditions. Generally, the post-stenotic tWSS was governed by near axisymmetric fluctuations, findings that where not consistent with conventional WSS disturbance predictors. At the 2-3 mm wall-offset range, a strong linear correlation was found between tWSS magnitude and near-wall turbulence kinetic energy (TKE), in contrast to the anisotropy indices, suggesting that MR-measured TKE can be used to assess elevated tWSS regions while tWSS anisotropy estimates request well-resolved simulation methods. (C) 2019 Elsevier Ltd. All rights reserved.

  • 68.
    Andersson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska fakulteten. Swedish E Science Research Centre SeRC, Sweden.
    Lantz, Jonas
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Swedish E Science Research Centre SeRC, Sweden.
    Ebbers, Tino
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Fysiologiska kliniken US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Swedish E Science Research Centre SeRC, Sweden.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Swedish E Science Research Centre SeRC, Sweden.
    Correction: Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions (vol 6, pg 281, 2015)2015Ingår i: Cardiovascular Engineering and Technology, ISSN 1869-408X, E-ISSN 1869-4098, Vol. 6, nr 4, s. 577-589Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation (LES) including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where the pre-stenotic hypoplastic segment may limit the possible improvement by treating the CoA alone. Spatiotem-poral maps of TKE and flow eccentricity could be linked to the characteristics of the post-stenotic jet, showing a versatile response between the CoA dilatations. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre-and immediate post treatment, as well as during follow-up studies.

  • 69.
    Andersson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska fakulteten.
    Lantz, Jonas
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten.
    Ebbers, Tino
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Fysiologiska kliniken US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Multidirectional WSS disturbances in stenotic turbulent flows: A pre- and post-intervention study in an aortic coarctation2017Ingår i: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wall shear stress (WSS) disturbances are commonly expressed at sites of abnormal flow obstructions and may play an essential role in the pathogenesis of various vascular diseases. In laminar flows these disturbances have recently been assessed by the transverse wall shear stress (transWSS), which accounts for the WSS multidirectionality. Site-specific estimations of WSS disturbances in pulsatile transitional and turbulent type of flows are more challenging due to continuous and unpredictable changes in WSS behavior. In these complex flow settings, the transWSS may serve as a more comprehensive descriptor for assessing WSS disturbances of general nature compared to commonly used parameters. In this study large eddy simulations (LES) were used to investigate the transWSS properties in flows subjected to different pathological turbulent flow conditions, governed by a patient-specific model of an aortic coarctation pre and post balloon angioplasty. Results showed that regions of strong near-wall turbulence were collocated with regions of elevated transWSS and turbulent WSS, while in more transitional-like near-wall flow regions a closer resemblance was found between transWSS and low, and oscillatory WSS. Within the frame of this study, the transWSS parameter demonstrated a more multi-featured picture of WSS disturbances when exposed to different types of flow regimes, characteristics which were not depicted by the other parameters alone. (C) 2016 Published by Elsevier Ltd.

  • 70.
    Andersson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Lantz, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ebbers, Tino
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation - Impact of Virtual Interventions2015Ingår i: Cardiovascular Engineering and Technology, ISSN 1869-408X, E-ISSN 1869-4098, Vol. 6, nr 6, s. 281-293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation (LES) including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies.

  • 71.
    Andersson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Lantz, Jonas
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    NON-INVASIVE INTERVENTION PLANNING OF STENOTIC FLOWS USING SCALE-RESOLVED IMAGE-BASED COMPUTATIONAL FLUID DYNAMICS2013Konferensbidrag (Refereegranskat)
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  • 72.
    Andersson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Lantz, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Turbulence Quantification of Stenotic Blood Flow Using Image-Based CFD: Effect of Different Interventions2014Ingår i: WCB 2014, 2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Turbulent blood flow is often associated with some sort of cardiovascular disease, e.g. sharp bends and/or sudden constrictions/expansions of the vessel wall. The energy losses associated with the turbulent flow may increase the heart workload in order to maintain cardiac output (CO). In the present study, the amount of turbulent kinetic energy (TKE) developed in the vicinity of an aortic coarctation was estimated pre-intervention and in a variety of post-intervention configurations, using scale-resolved image-based computational fluid dynamics (CFD). TKE can be measured using magnet resonance imaging (MRI) and have also been validated with CFD simulations [1], i.e. a parameter that not only can be quantified using simulations but can also be measured by MRI.

    Patient-specific geometry and inlet flow conditions were obtained using contrast-enhanced MR angiography and 2D cine phase-contrast MRI, respectively. The intervention procedure was mimicked using an inflation simulation, where six different geometries were obtained. A scale-resolving turbulence model, large eddy simulation (LES), was utilized to resolve the largest turbulent scales and also to capture the laminar-to-turbulent transition. All cases were simulated using baseline CO and with a 20% CO increase to simulate a possible flow adaption after intervention.

    For this patient, results shows a non-linear decay of the total amount of TKE integrated over the cardiac phase as the stenotic cross-sectional area is increased by the intervention.  Figure 1 shows the original segmented geometry and two dilated coarctation with corresponding volume rendering of the TKE at peak systole. Due to turbulent transition at a kink upstream the stenosis further dilation of the coarctation tends to restrict the TKE to a plateau, and continued vessel expansion may therefore only induce unnecessary stresses onto the arterial wall. 

    This patient-specific non-invasive framework has shown the geometrical impact on the TKE estimates. New insight in turbulence development indicates that the studied coarctation can only be improved to a certain extent, where focus should be on the upstream region, if further TKE reduction is motivated. The possibility of including MRI in a combined framework could have great potential for future intervention planning and follow-up studies.  

    [1] J. Lantz, T. Ebbers, J. Engvall and M. Karlsson, Numerical and Experimental Assessment of Turbulent Kinetic Energy in an Aortic Coarctation, Journal of Biomechnics, 2013. 46(11): p. 1851-1858.

  • 73.
    Andersson, Maria
    et al.
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik.
    Kristofferson, Hanna
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik.
    Structural Optimization of Product Families: With Application to Vehicle Body Structures2006Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    Some products share one or two modules and while developing these products, structural optimization with stiffness as the objective function can be a useful tool. There might be no or very little CAD-data available in the pre-development phase and it is not certain that existing designs can be, or is desirable to use as a reference. The main objective of this thesis is to establish an accurate and fast-to-use methodology which can be utilized while developing new cars.

    In this thesis, the Volvo products S40, V50 and C70 serve as a basis for this case study. All the models are beam structures and the masses of components are added as point and line masses. Several optimization analyses are performed on one or three products exposed to seven load cases. Additional analyses with shell elements, more simplified models and changed load case balance achieved by normalization of the different load case compliances are also studied to investigate how these factors influence the results.

    Analyses show that front crash to a great extent dominates the results while normalization increases the influence of the remaining load cases. Since front crash is dominating and the front area is shared in all products, the performance is remarkably similar when three products are optimized compared to separate analyses of one product. Analysis of models without added point or line masses gives a result which greatly differs from previous results and therefore shows that added masses are required. The methodology is applicable to develop products and detect new load paths through the car.

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  • 74.
    Andersson, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Produktionsekonomi.
    Bohman, Marcus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Produktionsekonomi.
    Effektivisering av produktionsflöde: Införande av ny teststrategi2009Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Ericsson AB i Katrineholm är en del av sektionen Business Unit Network i Ericsson koncernen. Fabrikens huvuduppgift är att producera kretskort i små volymer med en hög produktmix och med fokus på leveransprecision och kostnadseffektivitet. På fabriken tillverkas kretskort på avdelningen Modul. Avdelningen Modul har under en längre tid haft ett högt utfall av icke godkända kretskort i deras produktionssystem, vilket har lett till ett växande lager av felkort på företagets reparationsavdelning.

    Syftet med detta examensarbete är att undersöka hur Ericsson i Katrineholm kan öka utflödet av godkända artiklar i sin testprocess på avdelningen Modul.

    Som underlag för att ta fram förslag har en kartläggning av produktionsprocessen gjorts i form av värdeflödeskartor, där informationen har samlats in från Ericssons olika databaser QSP, Testnet och C:M. Information har även samlats in vid informella intervjuer. Företagets nuläge har analyserats med hjälp av teorier som genomflödestider och utnyttjandegrad och utifrån dessa har förslag tagits fram med hjälp av programmen Excel och C#.

    I nulägesanalysen framkom att den teststrategi man nu använder inte fungerar tillräckligt bra, detta eftersom kretskort som det inte är fel på skickas till reparationsavdelningen. Detta beror även på att teststationerna som finns på avdelningen Modul är väldigt instabila och att testoperatörerna inte besitter tillräckligt mycket kunskap om varje artikel.

    I rapporten presenteras en ny teststrategi som baseras på 5 olika kriterier och som är baserad på data som inhämtats från databasen SID 40 dagar tillbaka. Till teststrategin tas även kompletterande information fram till testoperatörerna för att underlätta deras arbete då det handlar om att ta beslut om ett kort/enhet ska testas om. Vid införande av nya teststrategin skulle ett värde av 1,6 miljoner kronor för kort och 3,25 miljoner kronor för enheter skickas vidare i systemet till kund istället för att skickas till reparationsavdelningen. Detta skulle dock öka utnyttjandet i resurserna, för kort med 9,2 och för enheter med 19,2 procent, men utnyttjandet för både kort och enheter är väldigt lågt, vilket medför att det inte borde påverka systemet i för stor utsträckning. Detta förutsätter dock att testprocessen presterar på samma sätt som den gjort de 40 senaste dagarna.

    Till sist presenteras resultatet i ett grafiskt gränssnitt för att underlätta för operatörerna på avdelningen Modul. Rekommendationerna som ges till Ericsson angående den nya teststrategin är att den bör användas som ett hjälpmedel och om den senare ska användas bör den integreras i den vanliga testmiljön.

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  • 75.
    Andersson, Peter
    Linköpings universitet, Ekonomiska institutionen.
    Exklusiva urmärken: en branschundersökning med avseende på positionering och val av urverk2006Självständigt arbete på grundnivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    Marknaden för armbandsur är stor, och den del av denna marknad som utgörs av exklusiva ur med högt pris tycks ha helt andra egenskaper än den för armbandsur i övrigt. Hur övertygas en konsument om att ett mekaniskt ur som avviker flera sekunder per dygn är att föredra framför ett elektroniskt som avviker några sekunder på ett år?

    Syftet med denna rapport är att ge en övergripande bild av marknaden för exklusiva ur och urverk, samt att analysera ett antal av de aktörer som finns på marknaden utifrån val av urverk och positionering.

    Rapporten beskriver elva exklusiva urmärken, med avseende på hur man i sin marknadskommunikation positionerar sig på marknaden. Märkena placeras in i en modell med två huvudsakliga dimensioner: pris och påverkan. Rapporten belyser även de mekaniska urverken. Vilka tillverkar dem? Hur används de, och vilken effekt får valet av urverk på märkenas prisläge och påverkan?

    Bland de märken som ingår i undersökningen visar rapporten att främst en tillverkare av urverk anlitas i mycket stor utsträckning: det Schweiziska företaget ETA. Med ett undantag - Rolex - köper samtliga av de i undersökningen ingående märkena urverk från ETA.

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  • 76.
    Andersson, Philip
    et al.
    Linköpings universitet, Tekniska högskolan, Filosofiska fakulteten, Institutionen för ekonomisk och industriell utveckling.
    Eklund, Tommy
    Linköpings universitet, Tekniska högskolan, Filosofiska fakulteten, Institutionen för ekonomisk och industriell utveckling.
    Analysis and Actions for Robust ElectronicsProduction at Haldex Brake Products Ltd2008Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    This master thesis report contains information about a project carried out at Haldex Brake Products that is situated in Redditch England. The Redditch site is part of the “Commercial Vehicle Systems” division within the Haldex group. Haldex Brake Products is designing and producing electronic anti lock brake systems. The latest product is called GEN2 and the project goal was to increase productivity and achieve more stability within the production processes of this product. The goal was achieved trough implementation suggestions affecting the three categories in overall equipment efficiency (OEE). Nine of the biggest implementations are presented in this report. Some of the suggestions are already implemented and some are under progress to be implemented. These implementations will result in an increase in productivity with additionally 953 products per week. The expected results are based on calculations on an average product. The report also contains suggestions for future actions to even more increase the efficiency of the production processes at Haldex Brake Products in Redditch.

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  • 77.
    Andersson, Rasmus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Engström, Fredrik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Compact lifting mechanism of autonomous vehicle: Concept development and guidelines for implementation2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The material handling industry is facing new challenges with the divergence from the established EUR-pallet. In correlation with the autonomous technology which is becoming more advanced, available and affordable than ever before, new demands are created. The industry calls for innovative material handling automated guided vehicles to meet the requirements. These vehicles will increase the owners profit by being more efficient in terms of time, size and cost. The aim for this study is to develop suitable lifting mechanisms for an ultra-compact automated guided vehicle. A generic product development process is utilized. The requirements for the lifting mechanism is defined and presented in a specification. A selection of employees are involved in the ideation and concept generation to add in-house knowledge and experience. The concepts are developed with component research, 3D visualizations and concept descriptions. The concepts are evaluated and the most promising are selected. The selected concepts are further developed with CAD-models, calculations and a selection of components. The concepts are compared with each other and the initial specification to assess the most suitable lifting mechanism. The single acting hydraulic system, including a Micro Power Pack and four small hydraulic cylinders, is considered the best suitable choice for an ultracompact material handling automated guided vehicle.

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  • 78.
    Andersson, Tobias
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    The flight perturbation problem: operational aircraft rescheduling2001Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    When there is a perturbation in a carefully planned flight schedule, e.g. an aircraft breakdown, it is important to minimize the negative consequences of this disturbance. In this thesis, a model and a number of solution strategies for the Flight Perturbation Problem is presented. Based on a connection network, a mixed integer multicommodity flow model with side constraints is developed. Cancellations, delays and aircraft swaps, both within the same fleet and between different aircraft types, are used to take care of the perturbation. The model also assures that the schedule returns to normal within a certain time.

    Six different solution strategies arc used to solve the model; the first based on a Lagrangian relaxation of the mixed integer multicommodity flow model. Four strategies are based on Dantzig-Wolfe decomposition and in two of them all feasible points are generated by a tree search algorithm before the master problem is solved, while the other two are column generation based. The last strategy is based on the metaheuristic tabu search.

    The computational tests with real problem data show that the Dantzig-Wolfe based strategies and the tabu search strategy arc very promising, and especially the tabu search strategies could be used in a real problem application that could provide airlines with solutions to complex perturbation problems.

  • 79.
    Andersson, Tommy
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Redesign av reduktionsutrustning i asselvalsverk inom stålindustri: Ett examensarbete utfört på konstruktionsbyrån BEKAB mot stålindustriföretaget Ovako2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Intresset för sömlösa stålrör med stora ytterdiametrar i förhållande till tunna väggtjocklekar har ökat tillsammans med att högre hållfasthet i olika stålsorter tillkommit. Detta gör det möjligt att tillverka lättare, billigare och mer materialeffektiva stålprodukter med samma eller högre hållfasthet som tidigare.

    Denna nya utvecklingsriktning medför förändringar och utmaningar i en av företaget Ovakos produktionslinor i Rörverk 5 Hofors, vilket de har behov av att samarbeta med maskinkonstruktionsföretaget BEKAB för att utvärdera och utveckla.

    I Ovakos produktionslina i Rörverk 5 finns en del av ett asselvalsverk som kallas för "förreducerare". Denna del av asselvalsverket ser Ovako ett stort intresse i att utvärdera och utveckla för att bättre anpassas till den nya utvecklingsriktningen.  En känd utmaning hos förreduceraren sen tidigare är att den från början är framtagen för att reducera ner ett kvalitetsproblem hos rörprodukterna som kallas för trattbildning. Projektet fördjupar sig därför inom trattbildning för att bättre förstå grunden till förreducerarens nuvarande design för att därefter genomföra en redesign av förreduceraren.

    I en nulägesanalys av nuvarande förreducerare framkommer ett flertal olika produktionsutrustningsproblem med tillhörande kvalitetsproblem hos rörprodukterna. Projektet väljer därmed att fokusera på de produktionsutrustningsproblem som ger störst effekt för förreduceraren om de löstes. Detta resulterar i ett nytt produktkoncept av förreduceraren i form av en visuell 3D-CAD-modell med tillhörande hållfasthetsberäkningar och materialoptimering.

    Studien behandlar ämnen som design, konstruktion, produktutveckling, hållfasthet samt materialoptimering.

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    Redesign av reduktionsutrustning i asselvalsverk inom stålindustri - Tommy Andersson
  • 80.
    Andersson, Torbjörn
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    Warell, Anders
    Lund University, Lund Sweden.
    Aesthetic Flexibility in the Management of Visual Product Branding2015Ingår i: Procedia Manufacturing, ISSN 2351-9789, Vol. 3, s. 2191-2198Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper will investigate the strategic design decision-making of an in-house designer in a company with a large product portfolio, with respect to how designers plan for future visual alterations of the product. In-house designers have to think strategically about the creation of recognition and differentiation through design because they influence the company’s overall strategies. Therefore, while balancing aesthetic and semiotic qualities of the product, designers have to consider current as well as future needs for recognition and product differentiation. The ability to do so is affected by cost and brand positioning strategy. An exploratory study was setup to investigate what design strategies could be found in an industrial design team employed by a company. The study exposed how in-house designers could strategically incorporate aesthetic flexibility in product parts in order to create opportunities for faster facelifts or redesigns. The importance of managing carry-over details in larger product portfolios was also discovered. To carry over parts from different products is an important way for a company to save money, development time and at the same time increase brand recognition through repetition. Carry-over can be an aid to enhance visual recognition, but it can also be a hindrance when the designer needs to create differencing design values. Most products have a lifespan before they need to be updated or redesigned, which depends on the competition in a product segment. This makes it extra important for designers to have an understanding of when to incorporate carry-over details and when not to. A model was created to describe how carry-over details, design cues and aesthetic flexibility could be managed in a product portfolio. The model is based on Rune Monö’s works and brand management literature, with an emphasis on the brand positioning framework of Point of Difference, Point of Parity and brand extension by Keller et al.

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  • 81.
    Andersson, Viktor
    et al.
    Chalmers, Sweden.
    Broberg, Sarah
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Hackl, Roman
    Chalmers, Sweden.
    Karlsson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Berntsson, Thore
    Chalmers, Sweden.
    Algae-based biofuel production as part of an industrial cluster2014Ingår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 71, s. 113-124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a study on the production of biofuels from algae cultivated in municipal wastewater in Gothenburg, Sweden. A possible biorefinery concept is studied based on two cases; Case A) combined biodiesel and biogas production, and Case B) only biogas production. The cases are compared in terms of product outputs and impact on global CO2 emissions mitigation. The area efficiency of the algae-based biofuels is also compared with other biofuel production routes. The study investigates the collaboration between an algae cultivation, biofuel production processes, a wastewater treatment plant and an industrial cluster for the purpose of utilizing material flows and industrial excess heat between the actors. This collaboration provides the opportunity to reduce the CO2 emissions from the process compared to a stand-alone operation. The results show that Case A is advantageous to Case B with respect to all studied factors. It is found that the algae-based biofuel production routes investigated in this study has higher area efficiency than other biofuel production routes. The amount of algae-based biofuel possible to produce corresponds to 31 MWfuel for Case A and 26 MWfuel in Case B.

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  • 82.
    Andreasson, Martin
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell Produktion.
    Irvall Karlsson, David
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell Produktion.
    Genomloppstidssänkning för lågvolymstillverkning med hög variation: En kartläggning av värdeflödet i en tillverkningsprocess av hylsor2018Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Examensarbetet har genomförts på SKF Mekan AB i Katrineholm som tillverkar lagertillbehör, bland annat lagerhus, hylsor och muttrar. I ett av de produktionsflöden som tillverkar hylsor har SKF Mekan AB problem med långa genomloppstider och överproduktion. Produktionsprocessen som tillverkar dessa hylsor är helt kundorderstyrd vilket betyder att alla artiklar som tillverkas där inte finns på lager utan tillverkas när kunden lägger en beställning.

    SKF Mekan AB ser den långa genomloppstiden som ett problem då det påverkar kunden och bidrar till högre kostnader, vilket har lett fram till arbetets syfte. Genom att undersöka flödet och ta reda på vilka faktorer som påverkar den långa genomloppstiden, har förbättringsförslag tagits fram för att ge SKF Mekan AB verktyg för att sänka genomloppstiden.

    Genom intervjuer och observationer har en undersökning av flödet kunnat genomföras. För att kunna utesluta var i flödet de bidragande faktorerna till den långa genomloppstiden befinner sig, har en värdeflödesanalys genomförts med hjälp av insamlade data. En litteraturstudie har legat till grund för vilka teorier och verktyg som kan användas för att lösa problem som SKF Mekan AB har.

    Resultatet från värdeflödesanalysen visade att bearbetningsmaskinen BBM101agerar flaskhals i flödet. De största bidragande faktorerna till skapandet av flaskhalsen är problem vid inkörning av nytt program och omställningar mellan olika produkter. Utöver dessa problem identifierades även oreda bland halvfärdigt och överproducerat material som stod utspritt i flödet. Genom att införa ett CAD/CAM system för beredningen, lägga mer fokus på 5Sarbetet och genomföra en SMED-analys skapas möjligheter till en sänkt genomloppstid.

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  • 83.
    Andric, J.
    et al.
    Chalmers, Sweden.
    Lindström, Stefan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Sasic, S.
    Chalmers, Sweden.
    Nilsson, H.
    Chalmers, Sweden.
    Ballistic deflection of fibres in decelerating flow2016Ingår i: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 85, s. 57-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the motion of inertial, rod-like fibres in the decelerating flow of a wedge-shaped channel with non-creeping fibre-flow interactions. We consider the trajectories of isolated fibres to identify the conditions for which these trajectories deflect from the streamlines of the flow as well as a rectilinear path. We carry out analytical and numerical studies under the assumption of an infinite fibre hydrodynamic resistance to transverse flow, and we expand the numerical study by taking into account a finite transverse hydrodynamic resistance. The analytical analysis identifies a longitudinal ballistic number Be and a transverse ballistic number B-t as two dimensionless parameters that govern the fibre dynamics. It is found that Be is the product of the Stokes number Ste(l) in the longitudinal direction of the fibre and the channel opening angle beta. As anticipated, a fibre moves along the streamlines in the viscosity-dominated regime (B-l amp;lt;amp;lt; 1, B-t amp;lt;amp;lt; 1), while it moves in a straight line without being rotated in the inertia-dominated regime (Bt amp;gt;amp;gt; 1). The focus of the present study is on the intermediate regime (B-l amp;gt;amp;gt; 1, B-t amp;lt; 1), in which we identify and analyse a fibre trajectory that significantly deviates from the streamlines of the flow. This behaviour is observed for both infinite and finite resistances to transverse flow, and it is referred to as ballistic deflection. We argue that ballistic deflection may increase the rate of collisions between suspended fibres, and thus potentially affects the rate of fibre aggregation in flowing suspensions. An order of magnitude estimate of the ballistic numbers identifies dry-forming of pulp mats, which includes an air-wood fibre flowing suspension, to operate in the regime of ballistic deflection. (C) 2016 Elsevier Ltd. All rights reserved.

  • 84.
    Andric, Jelena
    et al.
    Chalmers University of Technology.
    Fredriksson, Sam T.
    Chalmers University of Technology.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik. Linköpings universitet, Tekniska högskolan.
    Sasic, Srdjan
    Chalmers University of Technology.
    Nilsson, Håkan
    Chalmers University of Technology.
    A study of a flexible fiber model and its behavior in DNS of turbulent channel flow2013Ingår i: Acta Mechanica, ISSN 0001-5970, E-ISSN 1619-6937, Vol. 224, nr 10, s. 2359-2374Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamics of individual flexible fibers in a turbulent flow field have been analyzed, varying their initial position, density and length. A particle-level fiber model has been integrated into a general-purpose, open source computational fluid dynamics code. The fibers are modeled as chains of cylindrical segments connected by ball and socket joints. The equations of motion of the fibers contain the inertia of the segments, the contributions from hydrodynamic forces and torques, and the connectivity forces at the joints. Direct numerical simulation of the incompressible Navier-Stokes equations is used to describe the fluid flow in a plane channel, and a one-way coupling is considered between the fibers and the fluid phase. We investigate the translational motion of fibers by considering the mean square displacement of their trajectories. We find that the fiber motion is primarily governed by velocity correlations of the flow fluctuations. In addition, we show that there is a clear tendency of the thread-like fibers to evolve into complex geometrical configurations in a turbulent flow field, in fashion similar to random conformations of polymer strands subjected to thermal fluctuations in a suspension. Finally, we show that fiber inertia has a significant impact on reorientation timescales of fibers suspended in a turbulent flow field.

  • 85.
    Andric, Jelena
    et al.
    Chalmers, Sweden.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära.
    Sasic, Srdjan
    Chalmers, Sweden.
    Nilsson, Hakan
    Chalmers, Sweden.
    Numerical investigation of fiber flocculation in the air flow of an asymmetrical diffuser2014Ingår i: Proceedings of the 12th International Conference on Nanochannels, Microchannels and Minichannels (ICNMM), AMER SOC MECHANICAL ENGINEERS , 2014, nr V001T12A013, s. V001T12A013-Konferensbidrag (Refereegranskat)
    Abstract [en]

    A particle-level rigid fiber model is used to study flocculation in an asymmetric planar diffuser with a turbulent Newtonian fluid flow, resembling one stage in dry-forming process of pulp mats. The fibers are modeled as chains of rigid cylindrical segments. The equations of motion incorporate hydrodynamic forces and torques from the interaction with the fluid, and the fiber inertia is taken into account. The flow is governed by the Reynolds-averaged Navier-Stokes equations with the standard k - omega turbulence model. A one-way coupling between the fibers and the flow is considered. A stochastic model is employed for the flow fluctuations to capture the fiber dispersion. The fibers are assumed to interact through short-range attractive forces, causing them to interlock as the fiber-fiber contacts occur during the flow. It is found that the formation of fiber flocs is driven by both the turbulence-induced dispersion and the gradient of the averaged flow field.

  • 86.
    Andric, Jelena
    et al.
    Chalmers University of Technology.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik. Linköpings universitet, Tekniska högskolan.
    Sasic, Srdjan
    Chalmers University of Technology.
    Nilsson, Håkan
    Chalmers University of Technology.
    A particle-level fiber model, implemented in a general-purpose CFD code2013Ingår i: Svenska mekanikdagar, 2013, s. 113-Konferensbidrag (Övrigt vetenskapligt)
  • 87.
    Andric, Jelena
    et al.
    Chalmers University of Technology.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik. Linköpings universitet, Tekniska högskolan.
    Sasic, Srdjan
    Chalmers University of Technology.
    Nilsson, Håkan
    Chalmers University of Technology.
    A particle-level fiber model, implemented in OpenFOAM(R)2013Ingår i: 8th Int. OpenFOAM(R) Workshop, 2013Konferensbidrag (Övrigt vetenskapligt)
  • 88.
    Andric, Jelena
    et al.
    Chalmers University of Technology.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik. Linköpings universitet, Tekniska högskolan.
    Sasic, Srdjan
    Chalmers University of Technology.
    Nilsson, Håkan
    Chalmers University of Technology.
    A particle-level rigid fiber model for high-Reynolds number flow, implemented in a general-purpose CFD code2013Ingår i: 8th International Conference on Multiphase Flow ICMF 2013, Korea, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    A particle-level rigid fiber model has been integrated into a general-purpose, open source computational fluid dynamics code to carry out detailed studies of fiber--flow interactions in realistic flow fields. The fibers are modeled as chains of cylindrical segments, and their translational and rotational degrees of freedom are considered. The equations of motion contain the contributions from hydrodynamic forces and torques, and the segment inertia is taken into account. The model is validated for the rotational motion of isolated fibers in simple shear flow, and the computed period of rotation is in good agreement with the one computed using Jeffery's equation for a prolate spheroid with an equivalent aspect ratio. The model is applied by suspending a number of fibers in the swirling flow of a conical diffuser, resembling one stage in the dry-forming of pulp mats. The Reynolds-averaged Navier--Stokes equations with an eddy-viscosity turbulence model are employed to describe the fluid motion, and a one-way coupling between the fibers and the fluid phase is included. The dependence of the fiber motion on initial position and density is analyzed.

  • 89.
    Andric, Jelena
    et al.
    Chalmers University of Technology.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik. Linköpings universitet, Tekniska högskolan.
    Sasic, Srdjan
    Chalmers University of Technology.
    Nilsson, Håkan
    Chalmers University of Technology.
    Description and validation of a flexible fiber model, implemented in a general purpose CFD code2013Ingår i: 8th Int. Conf. Multiphase Flow ICMF 2013, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    A flexible fiber model has been implemented in a general purpose open-source Computational Fluid Dynamics code. The fibers are modeled as chains of cylindrical segments, and all the degrees of freedom necessary to realistically reproduce the dynamics of real fibers, are taken into account. Each segment is tracked individually and their equations of motion account for the hydrodynamic forces and torques from the interaction with the fluid, the elastic bending and twisting torques, and the connectivity forces and moments that ensure the fiber integrity. The segment inertia is taken into account and a one-way coupling with the fluid phase is considered. The model is applied to simulate the rotational motion of an isolated fiber in a low segment Reynolds number shear flow. In the case of a stiff fiber, the computed period of rotation is in good agreement with the one computed using Jeffery's equation for an equivalent spheroid aspect ratio. A qualitative comparison is made with experimental data for flexible fibers. Further, a generic test case is described and used to validate the energy conservation and the response time of the fiber model concept. These results show that the implemented model can reproduce the known dynamical behavior of rigid and flexible fibers successfully.

  • 90.
    Andric, Jelena
    et al.
    Chalmers University of Technology, Göteborg, Sweden.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik. Linköpings universitet, Tekniska högskolan.
    Sasic, Srdjan
    Chalmers University of Technology, Göteborg, Sweden.
    Nilsson, Håkan
    Chalmers University of Technology, Göteborg, Sweden.
    Rheological properties of dilute suspensions of rigid and flexible fibers2014Ingår i: Journal of Non-Newtonian Fluid Mechanics, ISSN 0377-0257, E-ISSN 1873-2631, Vol. 212, s. 36-46Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Particle-level simulations are used to study the rheology of monodispersed suspensions of rigid and flexible fibers in a creeping, simple shear flow of a Newtonian fluid. We also investigate the influence of different equilibrium shapes (straight and curved) of the fibers on the behavior of the suspension. A parametric study of the impacts of fiber flexural rigidity and morphology on rheology quantifies the effects of these realistic fiber features on the experimentally accessible rheological properties. A fiber is modeled as a chain of rigid cylindrical segments, interacting through a two-way coupling with the fluid described by the incompressible three-dimensional Navier–Stokes equations. The initial fiber configuration is in the flow–gradient plane. We show that, when the shear rate is increased, straight flexible fibers undergo a buckling transition, leading to the development of finite first and second normal stress differences and a reduction of the viscosity. These effects, triggered by shape fluctuations, are dissimilar to the effects induced by the curvature of stiff, curved fibers, for which the viscosity increases with the curvature of the fiber. An analysis of the orbital drift of fibers initially oriented at an angle to the flow–gradient plane provides an estimate for the time-scale within which the prediction of the rheological behavior is valid. The information obtained in this work can be used in the experimental characterization of fiber morphology and mechanics through rheology.

  • 91.
    Andric, Jelena S.
    et al.
    Chalmers University of Technology, Sweden.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Sasic, Srdjan M.
    Chalmers University of Technology, Sweden.
    Nilsson, Håkan
    Chalmers University of Technology, Sweden.
    PARTICLE-LEVEL SIMULATIONS OF FLOCCULATION IN A FIBER SUSPENSION FLOWING THROUGH A DIFFUSER2017Ingår i: Thermal Science, ISSN 0354-9836, E-ISSN 2334-7163, Vol. 21, s. S573-S583Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate flocculation in dilute suspensions of rigid, straight fibers in a decelerating flow field of a diffuser. We carry out numerical studies using a particle-level simulation technique that takes into account the fiber inertia and the non-creeping fiber-flow interactions. The fluid flow is governed by the Reynolds averaged Navier-Stokes equations with the standard k-omega eddy-viscosity turbulence model. A one-way coupling between the fibers and the flow is considered with a stochastic model for the fiber dispersion due to turbulence. The fibers interact through short-range attractive forces that cause them to aggregate into flocs when fiber-fiber collisions occur. We show that ballistic deflection of fibers greatly increases the flocculation in the diffilser. The inlet fiber kinematics and the fiber inertia are the main parameters that affect fiber flocculation in the predffuser region.

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  • 92.
    André, Samuel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Optimization of Valve Damping2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Öhlins CES Technologies in Jönköping have in the last 30 years been developing control valves for semi active suspension systems used in the car industry. The system, marketed by Öhlins under the brand name CES (Continuously controlled Electronic Suspension), enables a wide working range and ability to adapt to the current road conditions. By controlling  the valve in different ways there are also possibilities to decide on a specfic damper characteristic such as sport or comfort.

    The CES valve is working as a pilot controlled pressure regulator and is continuously controlled with help of an electro magnet. The CES valve is mounted in a uniflow damper which in turn guarantees the flow through the valve to go in only one direction independently ofdamper stroke direction.

    The rst part of the thesis investigates the damping characteristics in the latest model of the CES valve (i.e the CES8700). A simulation model is made to approximate the damping in the solenoid plunger. Questions that are answered are: How is damping dened, what creates damping in the valve, how large is the damping, what parameters aect the damping. The second part of the thesis investigates new and already prototyped damping concepts with help of simulation. This has been done in order to optimize the valve damping and in turn the damper performance. The simulation results show that the valve dynamics can be improved but often at the expense of a slower valve.

    Ladda ner fulltext (pdf)
    Mater_Thesis_Report-Optimization_of_Valve_Damping
  • 93.
    Angren, Jimmy
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Arnoldsson, Joel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Fjärrvärmens konkurrenskraft: En analys av olika uppvärmningsteknikers kostnadseffektivitet och kunders beslutsfattande2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Historiskt sett har den Svenska värmemarknaden dominerats av fjärrvärmen som i princip varit det enda kostnadseffektiva alternativet där det funnits tillgängligt. På senare tid har dock spelreglerna börjat på att förändras, bland annat på grund av värmepumparnas intåg, en förändrad energipolitik och ökade kundkrav – vilket har lett till en mer konkurrensutsatt marknad. Denna studie syftar till att både kvantitativt och kvalitativt analysera fjärrvärmens konkurrenskraft jämfört med alternativa uppvärmningstekniker, med fokus på segmenten flerbostadshus, övriga- samt offentliga lokaler.

    Efter en inledande marknadsundersökning bedömdes värmepumpar i kombination med el eller fjärrvärme, samt pellets i kombination med RME, kunna vara konkurrenskraftiga med fjärrvärme. Därefter beräknades livscykelkostnaden för dessa värmesystem för en generell fastighet som en funktion av dess energibehov och utnyttjningstid, samt för ett antal typanvändare. Dessa typanvändare identifierades genom att analysera förbrukningsstatistik från Vattenfall. Vidare genomfördes flera intervjuer med branschexperter parallellt med att en enkät sammanställdes som riktade sig till energi- och klimatrådgivare i Sverige. Enkäten syftade till att få en nulägesbeskrivning av fastighetsägares syn på värmemarknaden och på så sätt bidra till den kvalitativa analysdelen.

    Resultatet visar att det rent kostnadsmässigt är små skillnader mellan fjärrvärme och övriga alternativ givet de antaganden som författarna anser är rimliga. För ett typiskt flerbostadshus är fjärrvärme mer fördelaktigt men för en typisk övrig eller offentlig lokal är bergvärme ett marginellt bättre alternativ. Frånluftsvärmepump med fjärrvärme är i båda fallen en billig lösning. Dock visar känslighetsanalysen att det kan skilja med mer än en faktor 2,5 i livscykelkostnad för samtliga alternativ beroende på vilka antaganden som görs.

    Således är valet av värmesystem ur fastighetsägarens perspektiv nära kopplat till riskbedömning, vad denne tror om framtiden och vilken relation de har till nuvarande värmeleverantör. För alla fastighetsägare är säker och problemfri drift den viktigaste parametern utöver kostnaden. Det finns även en ovisshet kring framtida prishöjningar av både el- och fjärrvärme, vilket leder till osäkra kalkyler. Därför kan förtroendet och relationen med nuvarande värmeleverantör vara avgörande vid en beslutssituation. En hög investeringskostnad är också en tydlig barriär - parallellt som investeringen ofta konkurrerar med andra energi- och fastighetsåtgärder om samma budget. Miljöfrågan är viktig för offentliga lokaler och kan vara det även för övriga lokaler, men är sällan av stor betydelse för flerbostadshus.

    Sammanfattningsvis är det svårt att avgöra vilket alternativ som är mest konkurrenskraftigt i dagsläget. Flera faktorer spelar in och livscykelkostnaden kan variera kraftigt mellan bästa och sämsta fall för uppvärmningsalternativen. Emellertid indikerar denna studie att en effektbaserad prismodell leder till att fjärrvärmen stärker sin konkurrenssituation bland flerbostadshus men blir mer utsatt i segmenten offentliga respektive övriga lokaler. Särskilt i det senare är bergvärmepumpar ett växande hot.

    För att bibehålla sin konkurrenskraft är det viktigt att fjärrvärmeleverantörerna är transparenta och tydliga i kommunikationen mot sina kunder, framförallt när det gäller prisutvecklingen. På sikt kan affärsmodellen och erbjudandet behöva innafatta mer än bara värmeleveransen, exempelvis stöd vid energieffektivisering, miljöcertifierad värme samt ett komforterbjudande.

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    Fjärrvärmens konkurrenskraft
  • 94.
    Anistratov, Pavel
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Computation of Autonomous Safety Maneuvers Using Segmentation and Optimization2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis studies motion planning for future autonomous vehicles with main focus on passenger cars. By having automatic steering and braking together with information about the environment, such as other participants in the traffic or obstacles, it would be possible to perform autonomous maneuvers while taking limitations of the vehicle and road–tire interaction into account. Motion planning is performed to find such maneuvers that bring the vehicle from the current state to a desired future state, here by formulating the motion-planning problem as an optimal control problem. There are a number of challenges for such an approach to motion planning; some of them are how to formulate the criterion in the motion planning (objective function in the corresponding optimal control problem), and how to make the solution of motion-planning problems efficient to be useful in online applications. These challenges are addressed in this thesis.

    As a criterion for motion-planning problems of passenger vehicles on doublelane roads, it is investigated to use a lane-deviation penalty function to capture the observation that it is dangerous to drive in the opposing lane, but safe to drive in the original lane after the obstacle. The penalty function is augmented with certain additional terms to address also the recovery behavior of the vehicle. The resulting formulation is shown to provide efficient and steady maneuvers and gives a lower time in the opposing lane compared to other objective functions. Under varying parameters of the scenario formulation, the resulting maneuvers are changing in a way that exhibits structured characteristics.

    As an approach to improve efficiency of computations for the motion-planning problem, it is investigated to segment motion planning of the full maneuver into several smaller maneuvers. A way to extract segments is considered from a vehicle dynamics point of view, and it is based on extrema of the vehicle orientation and the yaw rate. The segmentation points determined using this approach are observed to allow efficient splitting of the optimal control problem for the full maneuver into subproblems.

    Having a method to segment maneuvers, this thesis further studies methods to allow parallel computation of these maneuvers. One investigated method is based on Lagrange relaxation and duality decomposition. Smaller subproblems are formulated, which are governed by solving a low-complexity coordination problem. Lagrangian relaxation is performed on a subset of the dynamic constraints at the segmentation points, while the remaining variables are predicted. The prediction is possible because of the observed structured characteristics resulting from the used lane-deviation penalty function. An alternative approach is based on adoption of the alternating augmented Lagrangian method. Augmentation of the Lagrangian allows to apply relaxation for all dynamic constraints at the segmentation points, and the alternating approach makes it possible to decompose the full problem into subproblems and coordinating their solutions by analytically solving an overall coordination problem. The presented decomposition methods allow computation of maneuvers with high correspondence and lower computational times compared to the results obtained for solving the full maneuver in one step.

    Delarbeten
    1. Segmentation and Merging of Autonomous At-the-Limit Maneuvers for Ground Vehicles
    Öppna denna publikation i ny flik eller fönster >>Segmentation and Merging of Autonomous At-the-Limit Maneuvers for Ground Vehicles
    2018 (Engelska)Ingår i: Proceedings of the 14th International Symposium on Advanced Vehicle Control, Beijing, July 16-20, 2018, 2018, s. 1-6Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    To decrease the complexity of motion-planning optimizations, a segmentation and merging strategy for maneuvers is proposed. Maneuvers that are at-the-limit of friction are of special interest since they appear in many critical situations. The segmentation pointsare used to set constraints for several smaller optimizations for parts of the full maneuver, which later are merged and compared withoptimizations of the full maneuver. The technique is illustrated for a double lane-change maneuver.

    Nyckelord
    vehicle automation and control, ground vehicle motion-planning, aggressive maneuvers
    Nationell ämneskategori
    Reglerteknik
    Identifikatorer
    urn:nbn:se:liu:diva-152222 (URN)
    Konferens
    The 14th International Symposium on Advanced Vehicle Control, Beijing, July 16-20, 2018
    Tillgänglig från: 2018-10-22 Skapad: 2018-10-22 Senast uppdaterad: 2019-11-21Bibliografiskt granskad
    2. Efficient Motion Planning for Autonomous Vehicle Maneuvers Using Duality-Based Decomposition
    Öppna denna publikation i ny flik eller fönster >>Efficient Motion Planning for Autonomous Vehicle Maneuvers Using Duality-Based Decomposition
    2019 (Engelska)Ingår i: IFAC PAPERSONLINE, ELSEVIER , 2019, Vol. 52, nr 5, s. 78-84Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    A method to decompose a motion-planning problem into several segments is presented. It is based on a modification of the original problem, such that certain variables at the splitting points are considered to be precomputed and thus fixed and the remaining variables are obtained by performing Lagrange relaxation. The resulting dual problem is split into several subproblems, allowing parallel computation. The method is formalized as a computational algorithm and evaluated in a safety critical double lane-change situation. The resulting maneuver has close-to-optimal behavior and, for certain initialization strategies, it is obtained in shorter computational time compared to computing the full maneuver in one step. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

    Ort, förlag, år, upplaga, sidor
    ELSEVIER, 2019
    Nyckelord
    trajectory and path planning; autonomous vehicles; duality-based decomposition; motion control; safety; intelligent transportation systems
    Nationell ämneskategori
    Beräkningsmatematik
    Identifikatorer
    urn:nbn:se:liu:diva-161215 (URN)10.1016/j.ifacol.2019.09.013 (DOI)000486629500014 ()
    Konferens
    9th IFAC International Symposium on Advances in Automotive Control (AAC)
    Anmärkning

    Funding Agencies|Wallenberg AI, Autonomous Systems and Software Program (WASP) - Knut and Alice Wallenberg Foundation

    Tillgänglig från: 2019-10-25 Skapad: 2019-10-25 Senast uppdaterad: 2019-11-21
    Ladda ner fulltext (pdf)
    Computation of Autonomous Safety Maneuvers Using Segmentation and Optimization
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    presentationsbild
  • 95.
    Ankarberg, Martin
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell Produktion.
    Jilnö, Erik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell Produktion.
    Redesign of Gas Hydraulic Suspension for Product Service System: A Master Thesis Work at Strömsholmen AB2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In these times, when manufacturing firms wonder how to integrate products and services into innovative offerings, how should products be designed to be of most value? This study is the investigation of this question for the manufacturing firm Strömsholmen AB, which designs gas springs and hydraulic suspension. The research has led to interviews of personnel to identify challenges and a workshop to generate new service ideas. By analyzing a specific gas hydraulic suspension product, this study shows that designing for product service systems (PSS) with a life-cycle perspective specifically for manufacturing, assembly, delivery, use, maintenance and remanufacturing, can greatly reduce costs and open up for innovative PSS business models. Using Design for Assembly, Design for Disassembly, Design for Serviceability and Design for Remanufacturing shows how concrete improvements to a product can be made. Improvements that show the potential of a redesign for the gas hydraulic suspension. Integrating products and services and pursuing the ideas and methods of this thesis, will ultimately make Strömsholmen better prepared to differentiate, to stay competitive, to deepen customer relations and to gain greater profits long-term.

    Ladda ner fulltext (pdf)
    fulltext
  • 96.
    Anund, Anna
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för samhällsmedicin. Linköpings universitet, Medicinska fakulteten. Swedish National Rd and Transport Research Institute, SE-58195 Linkoping, Sweden.
    Antonson, Hans
    Swedish National Rd and Transport Research Institute, SE-58195 Linkoping, Sweden; Lund University, Sweden.
    Ihlstrom, Jonas
    Swedish National Rd and Transport Research Institute, SE-58195 Linkoping, Sweden.
    Stakeholders Opinions on a Future In-Vehicle Alcohol Detection System for Prevention of Drunk Driving2015Ingår i: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 16, nr 4, s. 336-344Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: There is a common understanding that driving under the influence of alcohol is associated with higher risk of being involved in crashes with injuries and possible fatalities as the outcome. Various countermeasures have therefore from time to time been taken by the authorities to prevent drunk driving. One of them has been the alcohol interlock. Up to now, interlocks have mainly been used by previously convicted drunk drivers and in the commercial road transport sector, but not in private cars. Objective and Method: New technology has today reached a level where broader implementation might be possible. To our knowledge, however, little is known about different stakeholders opinions of a broader implementation of such systems. In order to increase that knowledge, we conducted a focus group study to collect in-depth thoughts from different stakeholders on this topic. Eight focus groups representing a broad societal span were recruited and conducted for the purpose. Results and Conclusions: The results show that most stakeholders thought that an integrated system for alcohol detection in vehicles might be beneficial in lowering the number of drunk driving crashes. They said that the system would probably mainly prevent driving by people who unintentionally and unknowingly drive under the influence of alcohol. The groups did, however, not regard the system as a final solution to the drunk driving problem, and believed that certain groups, such as criminals and alcoholics, would most likely find a way around the system. Concerns were raised about the risk of increased sleepy driving and driving just under the legal blood alcohol concentration (BAC) limit. The results also indicate that stakeholders preferred a system that provides information on the BAC up to the legal limit, but not for levels above the limit; for those, the system should simply prevent the car from starting. Acceptance of the system depended on the reliability of the system, on its ability to perform fast sampling, and on the analytical process, as well as the systems more or less inconspicuous placement and user-friendliness. The stakeholders thought that drivers would probably not voluntarily demand the system. So if broad implementation was desired, it would have to be made compulsory by legislation. As an incentive to increase demand, lower taxes and insurance premiums were suggested.

  • 97.
    Anund, Anna
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för samhällsmedicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Sinnescentrum, Rehabiliteringsmedicinska kliniken. Swedish National Rd and Transport Research Institute, Linkoping, Sweden.
    Ihlstrom, Jonas
    Swedish National Rd and Transport Research Institute, Linkoping, Sweden.
    Fors, Carina
    Swedish National Rd and Transport Research Institute, Linkoping, Sweden.
    Kecklund, Göran
    Stockholm University, Sweden.
    Filtness, Ashleigh
    Queensland University of Technology, Australia.
    Factors associated with self-reported driver sleepiness and incidents in city bus drivers2016Ingår i: Industrial Health, ISSN 0019-8366, E-ISSN 1880-8026, Vol. 54, nr 4, s. 337-346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Driver fatigue has received increased attention during recent years and is now considered to be a major contributor to approximately 15-30% of all crashes. However, little is known about fatigue in city bus drivers. It is hypothesized that city bus drivers suffer from sleepiness, which is due to a combination of working conditions, lack of health and reduced sleep quantity and quality. The overall aim with the current study is to investigate if severe driver sleepiness, as indicated by subjective reports of having to fight sleep while driving, is a problem for city based bus drivers in Sweden and if so, to identify the determinants related to working conditions, health and sleep which contribute towards this. The results indicate that driver sleepiness is a problem for city bus drivers, with 19% having to fight to stay awake while driving the bus 2-3 times each week or more and nearly half experiencing this at least 2-4 times per month. In conclusion, severe sleepiness, as indicated by having to fight sleep during driving, was common among the city bus drivers. Severe sleepiness correlated with fatigue related safety risks, such as near crashes.

  • 98.
    Apeaning, Raphael Wentemi
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Energy Efficiency and Management in Industries: a case study of Ghana’s largest industrial area.2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The judicious use of energy by industries is a key lever for ensuring a sustainable industrial development. The cost effective application of energy management and energy efficiency measures offers industries with an effective means of gaining both economic and social dividend, also reducing the negative environmental effects of energy use. Unfortunately, industries in developing countries are lagging behind in the adoption of energy efficiency and management measures; as such missing the benefits of implementation.

    This study is aims at enhance the knowledge of industrial energy efficiency and management strategies in Ghana, by investigating the present level of energy (and efficiency) management practices in Ghana largest industrial park (i.e. Tema industrial area). The study also incorporates the investigation of also investigation of barriers to and driving forces for the implementation of energy efficiency measure; to shed light on the rationale for both the adoption and non-adoption of cost effective industrial energy efficient technologies in Ghana. This study was carried out using a semi-structure interview due to the explorative nature of the study. The interviews were conducted in sessions, in the first session respondents were asked describe the energy management strategies in used in the respective companies. In the second session, respondents were asked to fill a structured questionnaire covering the various aspects of the study.

    The results reveal that energy is poorly managed in the industrial area and there is an energy efficiency gap resulting from the low implementation energy efficiency measures. In addition the reveals that the important barriers impeding the implementation of cost effective energy efficiency technologies or measures in the surveyed firms principally stems from rational behavior economic barriers, which are deeply linked to the lack of government frameworks for industrial energy efficiency. The study also finds that economic gains related to ‘cost reductions resulting from lowered energy use’ and ‘threats of rising energy prices’ are the most important drivers for implementing energy efficiency measures or technologies.

    Ladda ner fulltext (pdf)
    fulltext
  • 99.
    Arababadi, Reza
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Energy Use in the EU Building Stock - Case Study: UK2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Previous studies in building energy assessmnet have made it clear that the largest potential energy efficiency improvements are conected to the retrofitting of existing buildings. But, lack of information about the building stock and associated modelling tools is one of the barriers to assessment of energy efficiency strategies in the building stocks. Therefore, a methodology has been developed to describe any building stock by the means of archetype buildings.  The aim has been to assess the effects of energy saving measures. The model which is used for the building energy simulation is called:  Energy, Carbon and Cost Assessment for Buildings Stocks (ECCABS). This model calculated the net energy demand aggregated in heating, cooling, lighting, hotwater and appliances.

     

    This model has already been validated using the Swedish residential stock as a test case. The present work continues the development of the methodology by focusing on the UK building stock by discribing the UK building stock trough archetype buildings and their physical properties which are used as inputs to the ECCABS. In addition, this work seekes to check the adequacy of applying the ECCABS model to the UK building stock. The outputs which are the final energy use of the entire building stock are compared to data available in national and international sources.

     

    The UK building stoch is described by a total of 252 archetype buildings. It is determined by considering nine building typologies, four climate zones, six periods of construction and two types of heating systems. The total final energy demand calculated by ECCABS for the residential sector is 578.83 TWh for the year 2010, which is 2.6 % higher than the statistics provided by the Department of Energy and Climate Change(DECC). In the non-residential sector the total final energy demand is 77.28 TWh for the year 2009, which is about 3.2% lower than the energy demand given by DECC. Potential reasons which could have affected the acuracy of the final resualts are discussed in this master thesis. 

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    Thesis_Reza_Arababadi
  • 100.
    Aramrattana, Maytheewat
    et al.
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Andersson, Anders
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Reichenberg, Frida
    RISE Viktoria, Lindholmen Science Park, Lindholmspiren 3A, Gothenburg, Sweden.
    Mellegård, Niklas
    RISE Viktoria, Lindholmen Science Park, Lindholmspiren 3A, Gothenburg, Sweden.
    Burden, Håkan
    RISE Viktoria, Lindholmen Science Park, Lindholmspiren 3A, Gothenburg, Sweden.
    Testing cooperative intelligent transport systems in distributed simulators2019Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 65, s. 206-216Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Simulation is often used as a technique to test and evaluate systems, as it provides a cost-efficient and safe alternative for testing and evaluation. A combination of simulators can be used to create high-fidelity and realistic test scenarios, especially when the systems-under-test are complex. An example of such complex systems is Cooperative Intelligent Transport Systems (C-ITS), which include many actors that are connected to each other via wireless communication in order to interact and cooperate. The majority of the actors in the systems are vehicles equipped with wireless communication modules, which can range from fully autonomous vehicles to manually driven vehicles. In order to test and evaluate C-ITS, this paper presents a distributed simulation framework that consists of (a) a moving base driving simulator; (b) a real-time vehicle simulator; and (c) network and traffic simulators. We present our approach for connecting and co-simulating the simulators. We report on limitation and performance that this simulation framework can achieve. Lastly, we discuss potential benefits and feasibility of using the simulation framework for testing of C-ITS.

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