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  • 122501.
    Wentzel, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Huang, Xiyue
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Experimental characterization of the bending fatigue strength of threaded fasteners2015Ingår i: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 72, s. 102-108Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The fatigue strength in bending of pre-stressed steel bolts is investigated and compared to the fatigue strength in axial tension. The strength is measured in terms of maximum engineering stress amplitude, neglecting any stress concentration in the threads. The experimental results reveal that the fatigue limit is 76% higher in bending than in axial tension. A finite element model is used to compute the stress state in the threaded region for both axial tension and bending. It allows fitting a volume based weakest link model to the experimentally observed failure probabilities. Based on the good fit of the weakest link model it is argued that randomly distributed defects in the highly stressed thread root determine the fatigue strength.

  • 122502.
    Wentzel, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Olsson, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    A non-local friction model for efficient finite element modelling2008Rapport (Övrigt vetenskapligt)
  • 122503.
    Wentzel, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Olsson, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    A non-linear model for bolted joints based on deformation modes2008Rapport (Övrigt vetenskapligt)
  • 122504.
    Wentzel, Henrik
    et al.
    Scania CV AB.
    Olsson, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Influence from contact pressure distribution on energy dissipation in bolted joints2006Ingår i: Welding & Joining & Fastening & Friction Stir Welding, SAE International , 2006Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Energy dissipation due to micro-slip in joints is the primary source of damping in many vehicle and space structures. This paper presents results on how the surface topology may be modified to increase the energy dissipation in joints. An analytical solution for general forms of contact pressure of a one-dimensional micro-slip problem is presented. The solution indicates how the contact pressure should be distributed to maximize the energy dissipation. Two dimensional contact pressures are optimized using finite element methods in combination with numerical optimization methods and the results are used to modify the surface topology in bolted joints in order to increase the energy dissipation during loading. The predicted increase of energy dissipation is validated with physical testing. A direct result of the study is a washer with varying thickness increasing the energy dissipation in joints and hence the structural damping of joined structures.

  • 122505.
    Wentzel, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Olsson, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Mechanisms of dissipation in frictional joints: influence of sharp contact edges and plastic deformaiton2008Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 265, nr 11-12, s. 1814-1819Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present study frictional and plastic dissipation in joints are investigated by means of the finite element method. The Coulomb friction model is used in simulations and the results are compared to experimental measurements. Some of the contacts considered contain numerous internal sharp edges that are localized inside the overall contact region. For joints with sharp contact edges an elastic material model with Coulomb friction is inappropriate because of the sliding-over-edge that occurs in such joints. Here, the sliding-over-edge phenomenon is studied with an elastic-plastic material model in some detail. The phenomenon involves very high plastic strains locally, material build-up in front of the edge and large plastic dissipation. A summation technique for the total dissipation in joints is presented, where each local sliding-over-edge contribution is taken into account. The results are compared to experiments. It is shown that plastic deformation is an important contributing factor to the total dissipation in joints with highly non-conformal surfaces.

  • 122506.
    Wentzel, Henrik
    et al.
    Scania Commercial Vehicles AB.
    Olsson, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Numerical prediction of damping in structures with frictional joints2006Ingår i: International Journal of Vehicle Noise and Vibration, ISSN 1479-1471, Vol. 2, nr 2, s. 125-142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In many vehicle and space structures, friction in bolted joints is the primary source of energy dissipation during vibrations. Several simplified finite element models have proven their capacity to describe the energy dissipation owing to micro-slip in joints. However, these simplified models require extensive physical testing in order to extract model parameters. This paper proposes a methodology based on non-linear FE-analysis of the loading on joints for numerical evaluation of the energy dissipation due to micro-slip. The methodology is extended to allow for computation of modal damping in vibrating structures. Presented applications include studies of an isolated joint as well as a more complex structure subjected to dynamic excitation.

  • 122507.
    Wentzel, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Olsson, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Öberg, Martin
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Metallic inserts as a tool to alter the structural damping of joined structures2008Ingår i: International Journal of Surface Science and Engineering, ISSN 1749-785X, Vol. 2, nr 1-2, s. 152-167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic response of joined structures, notably the amplification of vibrations, is strongly influenced by the characteristics of the joints. Bolted joints are non-linear both in stiffness and magnitude of energy dissipation, and structures assembled with bolted joints inherit these non-linearities. This largely experimental study shows how thin metallic inserts in the contact region may serve as a tool to alter the non-linear properties of the joint and in this way increase or decrease the level of equivalent viscous damping in the structure. Both quasi-static and dynamic measurements have been performed and a mathematical model trimmed to the static measurements has been shown to produce valid results also for dynamic simulations.

  • 122508.
    Wentzel, Lisa
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Urban Mobility among Lower Income Communities in Jakarta: A Study of the Bus Rapid Transit System2010Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Urban planning research in developing countries has often focused on slum upgrading. Lately environmental issues have become increasingly important as well. Hence, transportation is an important field, as basis for the development of cities in developing countries, yet few studies on transport for the urban poor in developing countries have been conducted. Studies, which have been conducted, identify mobility as an important attribute for peoples employment opportunities, and, therefore, improving their living conditions. In Jakarta, transportation is, along with the battle against flooding and poverty, one of the most important issues for the future. This study explores the field of urban mobility in low-income communities in Jakarta, by looking at the newly implemented Bus Rapid Transit (BRT) system, through an explorative, descriptive and part explanatory approach. The BRT has been implemented to ease the chaotic traffic situation in Jakarta. But, in literature, BRT systems are argued to benefit the lower-income population as it provides cheap and fast transportation. The field study concludes that the BRT is used with restriction among the low-income residents, who were interviewed, due to several reasons. It infers that the BRT routes do not suite the travel patterns of the residents, besides, the fare including transfer costs becomes expensive. Consequently, the BRT has yet to make a significant impact on the low-income residents in Jakarta.

    Ladda ner fulltext (pdf)
    Final_Master_Degree_Project_Lisa_Wentzel
  • 122509.
    Wentzel, Sten Henrik Vilhelm
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Hållfasthetslära (Avd.).
    Models and mechanisms of dissipation in bolted joints2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 122510. Wen-Yong, Su
    et al.
    Yi, Luo
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi.
    Weak Gate Effect in 1,3-Benzenedithiol Molecular Device2010Ingår i: Chinese Physics Letters, ISSN 0256-307X, E-ISSN 1741-3540, Vol. 27, nr 4, s. 048502-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce a full interaction Hamiltonian method to the generalized quantum chemical approach and apply it to investigate the electron tunneling properties of 1,3-benzenedithiol molecular device. The weak gate effect we calculate is consistent with the experiment. The asymmetric current character mainly comes from the asymmetry of the molecule and the nonlinear responding to the gate electric field.

  • 122511.
    Werding, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Revenue requirements for mobile operators with ultra-high mobile broadband data traffic growth2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mobile broadband data access over cellular networks has been established as a major new service in just a few years. The mobile broadband penetration has risen to 10 to 15 per cent in Western European leading markets from 2007 to the end of 2009. More than 75% of network traffic was broadband data in 2009, and the data volumes are growing rapidly. But the revenue generation is the reverse as the average for operators in Europe in 2009 was around 77 per cent from voice, 10 per cent from SMS and 13 per cent from other data.

    Voice and broadband data service are built on two quite different business models. Voice pricing is volume based. Revenue depends linearly on the number of voice minutes. Broadband data service on the other hand is mainly flat fee based even if different levels are being introduced as well as tiers. Revenue is decoupled from traffic and therefore also from operating costs and investment requirements. This is what we define as a revenue gap. Earnings as well as internal financing will suffer from increasing traffic per user unless the flat fee can be raised or changed to volume based, other revenue can be obtained and/or operating costs and investments can be reduced accordingly.

    Observable trends and common forecasts indicate strong growth of mobile broadband traffic as well as declining revenue from mobile voice in the next five year period. This outlook suggests a prospective revenue gap with weak top-line growth and expanding operating costs and investment requirements. This is not only a profitability and cash flow issue. It may also severely restrict the industry’s revenue and profit growth potential if it is handled mainly by cost-cutting.

  • 122512.
    Werding, Jan
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Markendahl, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Mäkitalo, Östen
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Drivers of Novel Access Provisioning -Re-Use Aspects and Operator Cooperation2006Ingår i: 2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, IEEE , 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    New network and business architectures with low cost factors are necessary to promote development of extensive usage of a multitude of high data rate wireless services similar to the Internet. The novel access provisioning (NAP) project investigates the possibilities in local access and service provisioning as a complement to existing mobile networks. We expect that successful high bandwidth mobility services require more than local coverage even if wide area coverage is compromised. Many local access providers need to cooperate to make the service reasonably accessible. Different drivers of new market players and business models are analyzed.

  • 122513.
    Werding, Jan
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Markendahl, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Mäkitalo, Östen
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Novel access provisioning2006Ingår i: Helsinki Mobility Roundtable 2006, 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    New network and business architectures/Novel Access Provisioning (NAP) with low cost factors are necessary to promote development of extensive usage of a multitude of high data rate wireless services similar to the Internet.  The NAP project focus in particular on the investigation of possibilities in local access and service provisioning as a complement to existing Mobile Network Operators. We expect that successful high bandwidth mobility services require more than local coverage. Many local access providers need to cooperate to make the service reasonably accessible. Those can then be used to offload heavy and less price worthy traffic e.g. large down loads from the cellular network to local access points. Different drivers of new market players and business models are analyzed.

  • 122514. Werelius, P.
    et al.
    Thärning, P.
    Eriksson, Roland
    KTH, Tidigare Institutioner                               , Elkraftteknik.
    Holmgren, B.
    Gäfvert, U.
    Dielectric spectroscopy for diagnosis of water tree deterioration in XLPE cables2001Ingår i: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 8, nr 1, s. 27-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A HV dielectric spectroscopy system has been developed for diagnostics of water tree deteriorated extruded medium voltage cables. The technique is based on the measurement of nonlinear dielectric response in the frequency domain. Today's commercially available systems are capable of resolving low loss and small variations of permittivity as a function of frequency and voltage. Experience from more than 200 field measurements was combined with laboratory investigations. Small samples were used in an accelerated aging test to elucidate the correlation between water tree growth and dielectric response. Furthermore, field aged cables were investigated in the laboratory. It has been shown that the dielectric response of water tree deteriorated crosslinked polyethylene (XLPE) cables can be recognized and classified into different types of responses related to the aging status and breakdown strength. The influence of termination and artifacts such as surface currents was investigated. The measurement method enables us to separate the response of the cable from the influence of accessories. Finally, two different field studies of the implementation of the diagnostic method are presented. The field studies show that the fault rate decreased significantly when replacement strategy was based on the diagnostic criteria formulated.

  • 122515.
    Werelius, Peter
    KTH, Tidigare Institutioner                               , Elektrotekniska system.
    Development and application of high voltage dielectric spectroscopy for diagnosis of medium voltage XLPE cables2001Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    When polymer power cables were introduced into mediumvoltage applications in the late 1960s, the degradationphenomenon later referred to aswater treeingwas still unknown. However, this changedwithin a relatively short space of time. Just 5-10 years afterthese first polymer applications, faults began to appear thatcould be attributed to the new phenomenon-water treeing. Sincethen, cable manufacturers have been improving their designsgradually, and cables produced today are assumed to have muchlower susceptibility to water trees. However, water treeing isstill assumed to be the most important degradation process inthese applications.

    There are huge amounts of polymer cable installations thatare degraded by water trees. Since many of these cables areinstalled in the same grid nets, one cable fault oftengenerates another. If two or more cables fail at the same time,the consequences can be extensive. A non-destructive diagnosticmethod makes it possible to assess cables and take action priorto failures.

    This thesis presents the results of research work on thedevelopment of a measurement technique and diagnostic methodfor the assessment of medium voltage XLPE cables in the field.The method used is called high voltage dielectric spectroscopy,and involves the measurement of capacitance and loss as afunction of frequency at high voltages. The method is used in ashort frequency range of approximately one decade in thelow-frequency region (normally from 1 down to 0.1 Hz). Thevoltage levels used initially are all below the service-voltagelevel. If the cable is assessed to be free from water trees, aslightly increased voltage can be used.

    Based on dielectric-spectroscopy measurements, specificwater-tree analysis and breakdown tests, a set of measurementprocedures and criteria that take into account differences incable designs has been proposed for the assessment of mediumvoltage XLPE cables. The characteristic responses of XLPEcables (in both non and water-tree-deteriorated cases) make itpossible to separate the cable response from the influence ofaccessories. Field experience shows thatwater-tree-deteriorated cables with relatively low breakdownstrengths can remain in service for many years.

    Keywords:dielectric spectroscopy, high voltage,variable frequency, diagnostics, non-destructive diagnostics,cables, medium voltage, polymer, XLPE, water trees, watertreeing

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    FULLTEXT01
  • 122516. Werke, M.
    et al.
    Wretland, A.
    Ottosson, P.
    Holmberg, J.
    Machens, M.
    Semere, Daniel
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Geometric distortion analysis using a combination of the contour method and machining simulation2018Ingår i: Procedia CIRP, Elsevier, 2018, s. 1481-1486Konferensbidrag (Refereegranskat)
    Abstract [en]

    During machining the material removal releases residual stresses introduced by previous process steps. This causes geometric machining distortions and thereby high rejection rates and costs. By simulating the process chain it is possible to predict this type of distortions. However, this requires advanced material models and accurate process- and material data for the individual processes. In order to simplify the modelling efforts a methodology that combines the contour method with machining simulation is proposed. The methodology is validated for an aerospace component using deep layer removal X-ray diffraction and CMM measurements. The methodology will improve possibilities to reduce machining distortions.

  • 122517. Werke, Mats
    Methods and models for shot peening simulation2008Ingår i:   proceedings of the Swedish Production Symposium 2008, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

     

    Virtual methods for prediction of product properties induced by the manufacturing system may be a good support for product development and process optimisation. The shot peening process may increase component fatigue life by the introduction of compressive residual stresses and the goal of this literature survey was to investigate the industrial maturity of numerical models for shot peening simulation, developed in various R&D projects. The knowledge is based on the information in articles mainly presented at conferences arranged by the International Scientific Committee on Shot Peening. Some important aspects when virtually predicting residual stresses after shot peening are summarised. Several solutions were proposed with different geometric target conditions, material models and numbers of shots. A dynamic analysis with bilinear or multilinear hardening conditions where the target is a 3D block or cylinder of a small substrate below the surface may be a good approach. Also a pattern of several shots against the target should be considered. The state of the art concerning numerical models is still on a basic level and alternative methods, like parametric modelling, may therefore be a complement to numerical simulation. Here the user extracts polynomial relations between process parameters and residual stresses based on measurements.

  • 122518.
    Werke, Mats
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Principles for modelling of manufacturing sequences2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The manufacturing sequence influence, to a large extent, component properties like fatigue life, shape accuracy and manufacturability. By simulating the manufacturing sequence, using numerical or empirical models, and extracting important accumulated data, like residual stress, hardness and shape, the possibilities of early analysis of a design concept and the associated manufacturing sequence will increase. An established methodology has the potential of reducing physical testing and the time and costs of product design and process planning.

    This thesis proposes an algorithm to be used for setting up a framework of interconnected process step models. With support from the algorithm, it is possible to extract a virtual simulation sequence from a physical manufacturing sequence. Thereby, you can replicate the aggregated effects of process steps on part key features and manufacturing features. The algorithm will serve as a tool in process planning when establishing virtual manufacturing sequences. The virtual sequences should be used for virtual prediction of component properties, optimization of process parameters and evaluation of the effects of replacing, removing or adding process steps to a manufacturing sequence

    The algorithm is based on stepwise upstream selection of process steps, definition of interconnected models and selection of interconnected datasets using breadth first search. The algorithm completes existing procedures for data mapping and exchange of data between models into an overall approach for establishing virtual manufacturing sequences. Other scientific contributions are methods for modelling of deep rolling and blasting, a model material for validation of rolling and forging simulation and principles for integration of process simulation with CAD/CAM.

    Ladda ner fulltext (pdf)
    Thesis
  • 122519.
    Werke, Mats
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Simulation of manufacturing sequences for verification of product properties2009Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The manufacturing sequence may to a large extent influence properties like residual stresses and hardness and, as a consequence, the fatigue life and shape accuracy of a component. By simulating the manufacturing sequence and extract important accumulated data, the possibilities of early analysis of a design concept of a component and optimisation of the complete manufacturing sequence may increase. An established methodology has the potential to reduce physical testing, increase the process knowledge and reduce product development time and costs. This thesis suggests principles for simulating manufacturing sequences for forged and sheet metal-formed components.

    It is possible to establish virtual manufacturing sequences and connect different commercial simulation softwares into a chain with support from methods for data communication and in process modelling. However, the data communication has pitfalls and also material data, process data and material models for single processes may be insufficient in order to conduct a quantitative analysis of the accumulated properties. Thus, a thorough validation of the sequential simulation results should be performed. Further, engineering simplifications of the sequence are recommended and e.g. a combination of numerical and empirical methods may be preferable in order to predict accumulated results with high accuracy. Future development concerning standards for data communication as well as meshing, mapping and modelling technique is recommended in order to improve the quality of the accumulated results. Finally, methods for integration of sequential simulation in the overall component design process, including conventional Computer Aided Design (CAD) and Finite Element Analysis (FEA), should be developed. The main advantage of sequential simulation may be conceptual studies of process and material parameter variations and their influence on the final product properties.

    Paper I describes how to select the most critical process parameters in a manufacturing sequence. Paper II describes how to establish a sequence using a combination of numerical and empirical methods and paper III describes state of the art concerning shot peening simulation.

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    FULLTEXT02
  • 122520.
    Werke, Mats
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Bagge, Mats
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Nicolescu, Mihai
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Lindberg, Bengt
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Process modelling using upstream analysis of manufacturing sequences2015Ingår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 81, nr 9-12, s. 1999-2016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The manufacturing of components requires several manufacturing process steps that are performed in a sequence, during which the raw material is progressively converted into finished parts. The aim with simulation of manufacturing sequences is to replicate the aggregate effects of the process steps on key features of the finished product and manufacturing features. With the support of a successful simulation methodology, it will thereby be possible for process planners to evaluate virtually and select process steps to be included in the manufacturing sequence and to optimize process parameters. The motivation to implement sequential simulation in industry is therefore strong and will reduce time and cost in process planning. The modelling and simulation of complete manufacturing sequences is, however, a challenge which may lead to unrealistic and time-consuming modelling efforts and extensive computational requirements. This is due to the often complex material transformations through several consecutive process steps. In order to adapt sequential simulation into an industrial environment, simplifications are therefore necessary. This paper proposes a method for simplified metamodelling of manufacturing sequences, using upstream selection of process steps and definition of interconnected models. The method is presented as an algorithm and will improve the efficiency in the modelling of manufacturing sequences. The usability of the algorithm is demonstrated with two industrial cases: a bevel gear pinion and a steering arm.

  • 122521.
    Werke, Mats
    et al.
    Swerea IVF.
    Hedlind, Mikael
    Scania CV AB.
    Nicolescu, Mihai
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Geometric Distortion Analysis Using CAD/CAM Based Manufacturing Simulation2014Ingår i: Proceedings of the 6th International Swedish Production Symposium, Chalmers university , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Machining of components may cause geometric distortions and thereby quality issues and increased costs. This paper presents an engineering approach of CAD/CAM based manufacturing simulation in order to be in control of geometric distortions after machining. The method utilises STEP AP209 for communication of CAD/CAM simulation data. The method improves the ability to optimise process parameters, geometry, and material, in order to fulfil the design requirements. The method supports concurrent design and process planning using 3D models in CAD/CAM and FEM.

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    fulltext
  • 122522. Werke, Mats
    et al.
    Kristoffersen, Hans
    Haglund, Sven
    Svensson, Lennie
    Nord, Anders
    Prediciting residual stresses and hardness of a critical component using a combination of numerical and empirical methods2008Ingår i: Steel Research International Journal, ISSN 1611-3683, nr Sp. Iss. 2, s. 812-819Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the experiences gained when using numerical and empirical methods in order to predict the accumulated surface characteristics for a safety component after several forging steps, controlled cooling and blasting. The forging steps were simulated in a sequence using one Finite Element (FE) code. The output forging mesh was used as input to the cooling simulation but was too coarse in order to reflect surface characteristics. The decarburisation effect during cooling that may influence the surface characteristics was not included in the cooling model. An attempt to create a parametric model of the blasting machine with output residual stresses and hardness as a function of input residual stresses, hardness and process parameters indicated the need of further investigation concerning the physical phenomena during blasting in the machine. A new method was developed for analysing the influence of the blasted surface texture on the stress intensity. The measured residual stresses and hardness span caused by variations in the blasting process were successfully used together with the stress intensity factor as input to a fatigue strength analysis. In order to establish a seamless chain of models through the manufacturing sequence further development concerning cooling and blasting models is required.

  • 122523. Werke, Mats
    et al.
    Mosfegh, R.
    Johannesson, B.
    Svenningstorp, J.
    Stinstra, E.
    Statistical methods for extracting and evaluating manufacturing parameters of significant importance to component robustness2005Konferensbidrag (Refereegranskat)
    Abstract [en]

     

    The paper presents a methodology developed within the EURobust project (G1RD-CT-2002-00833 and IMS-Robust 97009, www.eurobust.net). Durability and robustness of components are combined effects of external loads, geometrical design, selected materials and manufacturing sequence. The influence of the manufacturing sequence has not yet been explored and implemented in the virtual product development process and this paper presents a new and unique method to help the engineer in invoking the effect of the manufacturing sequence on product properties. The methodology extracts and evaluates manufacturing parameters with a major influence on component durability. The method is a combination of engineering judgement, Variation Mode and Effect Analysis (VMEA), design of experiment plans for computer-based experiments, automatisation of Finite Element simulations and visualisation of results. The paper describes how to use the method when estimating the robustness of a forged steering knuckle where the deep rolling process was identified as the most important manufacturing process in the manufacturing sequence, using Failure Mode and Effect Analysis (FMEA). The impact on residual stresses, surface quality and deformation hardening from the deep rolling parameters such as tool diameter, hydrostatic pressure, circumferential spindle velocity, feed rate, etc was analysed using VMEA. A simulation model of the deep rolling process was developed and the variations of residual stresses as a function of the manufacturing parameters were simulated and analysed using graphical response surfaces. The method will help engineers to better control the design of components taking all aspects, including the manufacturing sequence, into consideration at the early design phase. The method will also increase the knowledge of how the manufacturing processes affect component durability. 

     

  • 122524.
    Werke, Mats
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi. Swerea IVF.
    Nicolescu, Mihai
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Semere, D.
    Variation analysis of manufacturing sequencesManuskript (preprint) (Övrigt vetenskapligt)
  • 122525.
    WERKELIN AHLIN, OSKAR
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    Implementation and evaluation of some platformindependent obfuscating transformations2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Vi studerar kodobfuskering, ett verktyg som används för att skydda mjukvara från att bakåtkompileras. När man obfuskerar programkod så komplicerar man exekveringsflödet och gör det på så sätt svårare för angripare eller konkurrenter att tyda den bakomliggande logiken hos programmet. Dagens bästa lösningar för kodobfuskering är beroende av en viss plattform. Vi utvärderar några plattformsoberoende obfuskeringsalgoritmer genom att implementera dem och utvärdera dem med avseende på ett antal definierade mätvärden. Obfuskeringsmetoderna implementeras med hjälp av ett vanligt kompilatorprojekt som baseras på öppen källkod. Vi konstaterar att det är gynnsamt att göra implementationerna på valt sätt. Givet implementationen av några vanliga obfuskeringsmetoder så utvärderar vi dem var för sig, och ensamma visar de sig inte vara så kraftfulla som förväntat. Vi kan dock konstatera att obfuskeringsmetoderna kan bli mycket mer kraftfulla om de appliceras i kombination med varandra.

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  • 122526.
    Werlinder, Marcus
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Tham, Emelie
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Application of Amazon Web Services in software development2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Under dem senaste åren så har molntjänster blivit ett allt mer populärt område, speciellt inom företag. Ett av dem största utgivare inom molntjänst branschen är Amazon som erbjuder skalbara och flexibla molntjänster. Molntjänster är dock ett relativt nytt område, vilket innebär att någon som inte är insatt i ämnet kan finna all tillgänglig information överväldigande och svår att bekanta sig med. Målet med det här tesen är att utforska olika Amazon Web Service som kan användas inom mjukvaruutveckling och observera problem som kan uppstå med dessa tjänster.

    Tre testapplikationer som använde sig av Amazon Web Services var skapade för att få en fördjupad kunskap om hur dessa tjänster fungerar och vad för möjligheter de har. Dessa applikationer utvecklades iterativt och en fallstudie utfördes för varje applikation. I början av varje ny iteration genomfördes en litteraturstudie, där källorna var kritiskt granskade för att se ifall dem innehöll väsentlig information för tesen. Sammanlagt användes nio olika Amazon Web Services för att implementera och testa de tre olika testapplikationerna. Resultaten från fallstudien tolkades och utvärderades med avseende på Amazon Web Services lärbarhet och tillämpningsbarhet. Problem som samlades ihop under utvecklingsprocessen visade att Amazons Web Services inte var särskilt användarvänligt för utvecklare med liten eller ingen erfarenhet inom Amazon Web Services.

    Ytterligare forskning inom andra Amazon Web Services som Elastic Cloud Computing och forskning som undersöker andra molntjänst plattformar som Google Cloud, skulle kunna bidra med en djupare förståelse och mer exakt inblick kring tillämpning av molntjänster.

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  • 122527.
    Werme, Lars O.
    et al.
    Department of Physics and Materials Science, Uppsala University, Sweden.
    Korzhavyi, Pavel A.
    Comment on Hultquist et al. ‘‘Water Corrodes Copper’’: [Catal. Lett. 132 (2009) 311]2010Ingår i: Catalysis Letters, ISSN 1011-372X, E-ISSN 1572-879X, Vol. 135, nr 3-4, s. 165-166Artikel i tidskrift (Övrigt vetenskapligt)
  • 122528.
    Werme, Mats
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Designing compliant mechanisms with stress constraints using sequential linear integer programmingManuskript (Övrigt vetenskapligt)
  • 122529.
    Werme, Mats
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Globally optimal benchmark solutions to some small-scale discretized continuum topology optimization problems2006Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 32, nr 3, s. 259-262Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this note, globally optimal solutions to three sets of small-scale discretized continuum topology optimization problems are presented. All the problems were discretized by the use of nine-node isoparametric finite elements. The idea is that these solutions can be used as benchmark problems when testing new algorithms for finding pure 0-1 solutions to topology optimization problems defined on discretized ground structures.

  • 122530.
    Werme, Mats
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    On Methods for Discrete Topology Optimization of Continuum Structures2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis consists of an introduction and seven appended papers. The purpose of the introduction is to give an overview of the field of topology optimization of discretized load carrying continuum structures. It is assumed that the design domain has been discretized by the finite element method and that the design variable vector is a binary vector indicating presence or absence of material in the various finite elements. Common to all papers is the incorporation of von Mises stresses in the problem formulations.

    In the first paper the design variables are binary but it is assumed that the void structure can actually take some load. This is equivalent to adding a small positive value, epsilon, to all design variables, both those that are void and those that are filled with material. With this small positive lower bound the stiffness matrix becomes positive definite for all designs. If only one element is changed (from material to void or from void to material) the new global stiffness matrix is just a low rank modification of the old one and thus the Sherman-Morrison-Woodbury formula can be used to compute the displacements in the neighbouring designs efficiently. These efficient sensitivity calculations can then be applied in the context of a neighbourhood search method. Since the computed displacements are exact in the 1-neighbourhood (when one design variable is changed) the neighbourhood search method will find a local optimum with respect to the 1-neighbourhood.

    The second paper presents globally optimal zero-one solutions to some small scale topology optimization problems defined on discretized continuum design domains. The idea is that these solutions can be used as benchmarks when testing new algorithms for finding pure zero-one solutions to topology optimization problems.

    In the third paper the results from the first paper are extended to include also the case where there is no epsilon>0. In this case the stiffness matrix will no longer be positive definite which means that the Sherman-Morrison-Woodbury formula can no longer be applied. The changing of one or two binary design variables to their opposite binary values will still result in a low rank change, but the size of the reduced stiffness matrix will change with the design. It turns out, however, that it is possible to compute the effect of these low rank changes efficiently also without the positive lower bound. These efficient sensitivity calculations can then be used in the framework of a neighbourhood search method. In this case the complete 1-neighbourhood and a subset of the 2-neighbourhood is investigated in the search for a locally optimal solution.

    In the fourth paper the sensitivity calculations developed in the third paper are used to generate first and partial second order approximations of the nonlinear functions usually present in topology optimization problems. These approximations are then used to generate subproblems in two different sequential integer programming methods (SLIP and SQIP, respectively). Both these methods generate a sequence of iteration points that can be proven to converge to a local optimum with respect to the 1-neighbourhood. The methods are tested on some different topology optimization problems.

    The fifth paper demonstrates that the SLIP method developed in the previous paper can be applied also to the mechanism design problem with stress constraints. In order to generate the subproblems in a fast way small displacements are assumed, which implies that the efficient sensitivity calculations derived in the third paper can be used. The numerical results indicate that the method can be used to lower the stresses and still get a functional mechanism.

    In the sixth paper the SLIP method developed in the fourth paper is used as a post processor to obtain locally optimal zero-one solutions starting from a rounded solution to the corresponding continuous problem. The numerical results indicate that the method can perform well as a post processor.

    The seventh paper is a theoretical paper that investigates the validity of the commonly used positive lower bound epsilon on the design variables when stating and solving topology optimization problems defined on discretized load carrying continuum structures. The main result presented here is that an optimal "epsilon-1" solution to an "epsilon-perturbed" discrete minimum weight problem with constraints on compliance, von Mises stresses and strain energy densities, is optimal, after rounding to zero-one, to the corresponding "unperturbed" discrete problem. This holds if the constraints in the perturbed problem are carefully defined and epsilon>0 is sufficiently small.

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  • 122531.
    Werme, Mats
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Using the sequential linear integer programming method as a post-processor for stress-constrained topology optimization problems2008Ingår i: International Journal for Numerical Methods in Engineering, ISSN 0029-5981, E-ISSN 1097-0207, Vol. 76, nr 10, s. 1544-1567Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper deals with topology optimization of load-carrying structures defined on discretized continuum design domains. In particular, the mininium compliance problem with stress constraints is considered. The finite element method is used to discretize the design domain into n finite elements and the design of a certain structure is represented by an n-dimensional binary design variable vector. In order to solve the problems, the binary constraints on the design variables are initially relaxed and the problems are solved with both the method of moving asymptotes and the sparse non-linear optimizer solvers for continuous optimization in order to compare the two solvers. By solving a sequence of problems with a sequentially lower limit on the amount of grey allowed, designs that are close to 'black-and-white' are obtained. In order to get locally optimal solutions that are purely {0, 1}(n). a sequential linear integer programming method is applied as a post-processor. Numerical results are presented for some different test problems.

  • 122532.
    Werne Solnestam, Beata
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Interpreting the human transcriptome2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Människokroppen är uppbyggd av miljarder celler och nästan alla innehåller samma arvsmassa. Trots detta finns det många olika celler med olika funktioner vilket är en följd av vilken del av arvsmassan som cellerna använder, dvs vilka RNA-molekyler som finns i varje cell. Den snabba utvecklingen av sekvenseringstekniker har gjort det möjligt att studera när, var och hur varje RNA-molekyl är uttryckt och att få en djupare förståelse för hur människans celler fungerar.

    Arbetet som presenteras i denna avhandling fokuserar på analys av RNA-molekyler i människans celler. I artikel I beskriver vi en automatiserad metod för att förbereda cellprov för RNA-sekvensering. Det automatiserade protokollet jämfördes med det manuella protokollet, och vi visade att det automatiserade protokollet överträffade det manuella när det gällde provkapacitet samtidigt som en höga reproducerbarheten behölls. I artikel II undersökte vi effekterna som RNA-molekyler från en del av cellen (cellkärnan) har på den totala mängden uttryckta RNA-molekyler. Vi jämförde RNA från hela cellen och från en del av cellen (cytoplasman) och visade att RNA-molekyler med långa och strukturerade 3'- och 5'-otranslaterade regioner och RNA-molekyler med långa proteinkodande sekvenser tenderade att hållas kvar i cellkärnan till en högre grad. Detta resulterade i en ökad komplexitet av RNA-molekylerna i hela cellen, medan vi i cytoplasma-fraktionen lättare kunde hitta de korta och svagt uttryckta RNA-molekyler. I Artikel III och IV studerar vi RNA-molekyler i människans skelettmuskler. I artikel III visar vi att andelen RNA-molekyler uttryckta i skelettmuskler är väldigt lika mellan muskler och mellan olika personer, men att ett stort antal RNA-molekyler var uttryckta i olika nivåer hos kvinnor och män. Artikel IV beskriver RNA-nivåer som svar på upprepade perioder av uthållighetsträning. Artikel V beskriver en metod för att studera ett fåtal utvalda RNA-molekyler. Vi valde RNA-molekyler vars uttryck är viktigt vid analys av bröstcancerceller, och optimerade metoden för analys av enskilda celler. Vi analyserade cancerceller från blodprov och använde metoden för att titta på RNA-nivåer i enskilda celler från en grupp av celler och visade på skillnader i RNA-nivåer inom gruppen.

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    Thesis Beata Werne Solnestam
  • 122533.
    Werne Solnestam, Beata
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Stranneheim, Henrik
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Hällman, Jimmie
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Käller, Max
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lundberg, Emma
    KTH, Skolan för bioteknologi (BIO), Proteomik (stängd 20130101). KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lundeberg, Joakim
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Akan, Pelin
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Comparison of total and cytoplasmic mRNA reveals global regulation by nuclear retention and miRNAs2012Ingår i: BMC Genomics, ISSN 1471-2164, E-ISSN 1471-2164, Vol. 13, nr 1, s. 574-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The majority of published gene-expression studies have used RNA isolated from whole cells, overlooking the potential impact of including nuclear transcriptome in the analyses. In this study, mRNA fractions from the cytoplasm and from whole cells (total RNA) were prepared from three human cell lines and sequenced using massive parallel sequencing. Results: For all three cell lines, of about 15000 detected genes approximately 400 to 1400 genes were detected in different amounts in the cytoplasmic and total RNA fractions. Transcripts detected at higher levels in the total RNA fraction had longer coding sequences and higher number of miRNA target sites. Transcripts detected at higher levels in the cytoplasmic fraction were shorter or contained shorter untranslated regions. Nuclear retention of transcripts and mRNA degradation via miRNA pathway might contribute to this differential detection of genes. The consequence of the differential detection was further investigated by comparison to proteomics data. Interestingly, the expression profiles of cytoplasmic and total RNA correlated equally well with protein abundance levels indicating regulation at a higher level. Conclusions: We conclude that expression levels derived from the total RNA fraction be regarded as an appropriate estimate of the amount of mRNAs present in a given cell population, independent of the coding sequence length or UTRs.

  • 122534.
    Werner, Arne
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    Predicting translational diffusion of evolutionary conserved RNA structures by the nucleotide number2011Ingår i: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 39, nr 3, s. e17-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ribonucleic acids are highly conserved essential parts of cellular life. RNA function is determined to a large extent by its hydrodynamic behaviour. The presented study proposes a strategy to predict the hydrodynamic behaviour of RNA single strands on the basis of the polymer size. By atom-level shell-modelling of high-resolution structures, hydrodynamic radius and diffusion coefficient of evolutionary conserved RNA single strands (ssRNA) were calculated. The diffusion coefficients D of 17-174 nucleotides (nt) containing ssRNA depended on the number of nucleotides N with D = 4.56 x 10(-10) N-0.39 m(2) s(-1). The hydrodynamic radius R-H depended on N with R-H = 5.00 x 10(-10) N-0.38 m. An average ratio of the radius of gyration and the hydrodynamic radius of 0.98 +/- 0.08 was calculated in solution. The empirical law was tested by in solution measured hydrodynamic radii and radii of gyration and was found to be highly consistent with experimental data of evolutionary conserved ssRNA. Furthermore, the hydrodynamic behaviour of several evolutionary unevolved ribonucleic acids could be predicted. Based on atom-level shell-modelling of high-resolution structures and experimental hydrodynamic data, empirical models are proposed, which enable to predict the translational diffusion coefficient and molecular size of short RNA single strands solely on the basis of the polymer size.

  • 122535.
    WERNER, FREDRIK
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.), Entreprenörskap och Innovation.
    Ecommerce and market structure effects in theEuropean retail industry2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Fifteen or so years into what is said to be the game changer of our time there are many fields of science  focusing  their  attention  towards  the  online  market  in  attempts  to  describe  its implications for the traditional, offline markets. Where most of the literature on economics of ecommerce focus on pricing mechanisms and growth little attention has been directed towards more general market structure effects. This thesis adopts techniques, empirical and theoretical models  from  the  search  cost  and  market  structure  literature  in  order  to  examine  the relationships between ecommerce and offline market structures in the retail industry through regional employment and establishment data. The literature reviewed and used focus only on the US market whereas this thesis shifts the attention to the European regions. The results are convincing and in general corresponding to previous research results. As ecommerce usage increase and the consumer search costs thereby gets lower inefficient firms drop out of the market resulting in a decline in local establishment counts. The opposite effect is seen for pure online retailing establishments that thrive in the presence of local ecommerce usage. The effect of   ecommerce  on  traditional  offline  establishments  seems  to  be  aggregated  phenomena whereas  the  effect  on  pure  online  firms  seems  to  be  of  a  more  local  nature.  Focus  of policymakers and company management therefore might consider looking at the two effects in their respective aggregation level to best sort out how to react in the presence of increased competition from ecommerce usage.

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  • 122536.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Boendeattityder till miljö- och kretsloppsanpassning: Drivkrafter och motkrafter i olika upplåtelseformer2004Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Swedish political goals on environmental issues are set at a high standard and fulfilling them will affect the everyday life of all residents. Voluntary self-restraint from benefits in housing services is hard to implement. This is an empirical study on actual habits and on stated willingness for pro-environmental practices, related to different forms of tenure.

    Incentives and perceived control are important for predicting actions. Administrative and physical structures are more significant though, as are the households’ resources. Well–off homeowners have many incentives to conserve energy and water. They also have the highest frequency of pro-environmental behaviour. Still they cause the heaviest environmental impact, due to large dwellings and abundant car use. Households in multifamily housing have fewer incentives and lower frequencies of pro-environmental habits, but cause less environmental impact due to generally lower consumption.

    The results are of interest to planning authorities, housing managers and researchers, working with the implementation of pro-environmental behaviour in housing.

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  • 122537.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Bostadskvalitet idag: en utvärdering av nybyggda bostäder, ur kundens synvinkel2008Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    INTRODUKTION

    Bakgrund

    Syfte

    Kunskapsläget

    METOD

    Angreppssätt och avgränsning

    Intervjuer

    Observationer

    Expertbedömning av planer och inredning

    Urval

    • Totalurvalet - läge, storlek och lägenhetssammansättning
    • De undersökta projekten och intervjuade hushåll

    RESULTAT

    Bakgrund till bostadsvalet

    Överlåtelse och tillval

    Husets gemensamma funktioner

    • Utemiljön
    • Utsikt och insyn
    • Parkering
    • Posthantering
    • Förråd
    • Sophantering
    • Tvättstuga och träfflokaler

    Bostadens tekniska egenskaper

    • Temperatur
    • Luftkvalitet och ventilation
    • Ljudstörningar

    Rummen

    • Köket
    • Vardagsrummet
    • Sovrum
    • Hygienrum
    • Förråd/klädkammare
    • Entré
    • Balkong eller terrass

    Bedömning av bostaden som helhet

    • Ljus
    • Öppenhet och genomblick
    • Det bästa med bostaden
    • Rumssamband och rummens storlek
    • Expertbedömning av några bostadsexempel
    • De boendes bedömning av samma bostäder

    Sammanfattning av resultaten

    • Goda kvaliteter
    • Kritiska punkter

    DISKUSSION OCH SLUTSATSER

    Konflikter mellan olika kvaliteter

    Förbättringsmöjligheter

    Bostadsutformningens utveckling

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  • 122538.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Byggnadsutformning och förvaltningsekonomi: fallstudier i 20 bostadsfastigheter i Stockholm1996Licentiatavhandling, monografi (Övrigt vetenskapligt)
  • 122539.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    How does the planning goal 'urban density' correspond to people's residential choices and everyday life?: A pilot study2009Konferensbidrag (Refereegranskat)
  • 122540.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    How does the planning goal ’urban density’ correspond to people’s residential choices and everyday life?: Affordances in differing urban densities2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper presents the basis of a project recently funded by FORMAS, Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning. Although there is consensus among planners and politicians that dense and compact cities are better for the environment than sprawling urban landscapes, much of what is currently being built is characterised by low urban density, ‘sprawl’. Generally researchers agree that ‘sprawl’ in industrialised countries is driven by rising average income and decreasing transport costs. Urban households can afford to demand larger dwelling units as well as daily travel long dis-tances. Individual decisions are aggregated into a force that governs the development towards ’sprawl’. The aim of the project is to analyse how urban environments can offer desired qualities, by studying households’ actual use and valuation of opportunities for work, service, leisure ac-tivities, culture and education within areas of different urban density. The contribution of the study will be a deeper understanding of what urban density means in the daily life of house-holds. The study will employ theories and concepts from planning research and environmental psy-chology. Urban density is a key concept. Range and variety of urban functions are then impor-tant additions to measurement of physical densities. Another key concept is ‘affordance‘. ’Affordance’ is here a quality or asset within a specific environment, which can be perceived and used by an individual for carrying out a certain activity. The main study is a survey covering around 2000 households within the Stockholm area. Four areas will be chosen, and around 500 households in each, admitting control for socio-economic subgroups. Study areas will be selected to illustrate different urban densities and structure, from inner city to garden suburb. The survey will cover blocks of questions con-cerning the most important affordances inherent in the actual environment of the household, such as place of work, shops, schools and social networks. The questions will be constructed to grade perceived, potential, shaped and utilised affordances in their environment. The concept of ’affordance’ will be tested as a tool for structured comparisons between urban areas regarding different aspects of density. The availability of affordances in different urban structures will be described and relationships between density, in all its aspects, and life styles can be tested.

  • 122541.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Kvalitetsutveckling i boendet-Värdeskapande processer, Rapport från tre fallstudier : Rissne i Sundbyberg, Berga i Linköping och Gottsunda i Uppsala2007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The research on housing quality is comprehensive and broad. Residents’ evaluation of quality is studied within a variety of disciplines. There is a fairly good knowledge on a general level regarding people’s values of housing quality. Safety and security, social relations to neigh-bours, the area’s reputation as well as the design of local environment and dwelling units have been shown to be important aspects of housing quality.

    The overall picture of how to strike the balance between certain levels of quality against input of resources from the housing management is not studied to the same extent. Different actors within housing management may have differing and even conflicting views of quality and efficiency. Short-term economical judgements can increase the risk of sub-optimisations.

    Substantial evidence shows that social capital is critical for increasing security and wellbeing in residential areas. The hypothesis is that the creation of social capital within a housing neighbourhood will raise housing quality and facilitate management.

    The purpose of this study was to analyse the creation of social capital in a housing neighbourhood context, to make the concept applicable in housing management. A complementary aim was to develop indicators for social capital in housing areas, useful for evaluating the effects of different measures. To find out new methods for the development of housing quality, the study applied case studies of housing management, for evaluation of quality efforts. A multi-disciplinary framework was adopted. Theories of social capital and models for value creation processes are the key concept in the project.

    The core of value creation processes is to produce more value at a given input of resources. The basic idea is that value can be created through the supply of goods or services in new ways or in a new form. The customer / consumer is part of the process and will, through this participation, experience a higher quality (Cars, Healey, Madanipour, Magalhães, 2002).

    Several theorists in sociology, for example Bourdieu and Coleman, have interpreted social capital. The starting point for this project is primarily the concept as coined by Robert Putnam: ”Social capital here refers to features of social organization, such as trust, norms, and networks, that can improve the efficiency of society by facilitating coordinated actions.” (Putnam, 1993, p. 167). Social capital is seen a common utility, a form of capital that is not owned by individuals, but is created and growing in interpersonal relations, for example among neighbours in a residential area. Putnam (2000) and Lin (2001) discuss the epithets 'bonding' and 'bridging' in connection with SC. Bonding SC tends to exclude other individuals or groups, while the group that possesses the bonding capital benefits from it. Bridging SC will increase trust in other groups and structures in society and contribute to the identification and mutual cooperation with others. In residential areas SC can be a great asset, but the balance between bonding and bridging SC is critical.

    The study objects were management projects in a number of public housing companies. The criteria for selection of projects for the study were that their purpose should be to improve housing quality and / or trust and norms between companies and residents. There should be enough of accessible information on the measures taken and the projects should be fairly recent so that staff and residents of the company had clear memories of what happened before, during and after the process. The study covered four case studies, from different medium sized Swedish cities. Data were collected through interviews with key actors and residents, questionnaires to residents and document studies.

    The projects were compared regarding how they were designed to achieve their goals, and to what degree they managed to attain those goals. The intention was to find out more about the successes or failures in terms of management measures, regarding the enhancement of participation, security and social capital in the residential areas.

    The four case studies focused on very different types of measures. One project aimed at increasing perceived security in a residential area by introducing a special watchman who would offer protection, assistance and social control. Next project held youth activities for primary school children, to prevent youth delinquency. Sports clubs gave free instruction, the municipality offered venues for free and the school administered the activities in cooperation with the housing company. The third project was the renovation of outdoor environment and common areas like laundry rooms and entrances, in a residential area with social problems, to make the area more attractive. The fourth project was a campaign among tenants to counteract the perception of water as a free resource and in particular reduce the consumption of hot water.

    The results showed that the projects did not fully meet their stated objectives; to the extent it was possible to make such assessments. The companies had not ensured that there was data to verify the compliance to goals before they started their actions. Rather, the projects may be seen as building up experience in the housing management practice.

    The companies themselves have not mentioned the concept of social capital during the planning of the various projects. In practice though, the addressed management problems could be defined as stemming from deficits in social capital. Where the residents did not trust their neighbours there was a lack of bonding capital. If residents saw themselves as victims of circumstances, unable to influence their own situation, the bridging capital was missing.

    Social capital can be built from personal relationships between residents and housing companies and between the residents. With time bonding social capital is built up. This in turn contributes to the fostering of bridging social capital. When the residents see that commitment and work for the common good pays off in different ways, trust in the housing company will grow and in a longer perspective also trust in the surrounding society. To participate in the housing management and take on responsibilities can provide new life opportunities, such as an entrance ticket to the job market.

    The case studies showed that housing quality is a complex concept. It is a 'fresh product' that must be constantly maintained and developed. Various conditions can affect what is perceived as housing quality, and quality must be kept up all the time. To achieve the best quality as perceived by residents, it is a prerequisite that residents are involved to a high degree.

    Reasoning based upon literature and the empirical results suggests that important indicators of social capital in housing areas are related to trust, norms of reciprocity, social control, social networks and civic participation. With regard to if they are manifest on micro, meso or macro level, the indicators will take on different forms, discussed in a forthcoming article.

    The results have been presented at seminars with the housing companies, in teaching undergraduate students at KTH, in a report in Swedish, and in conference papers.

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  • 122542.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Livscykel och livsstil: olika konsumentgruppers bostadsval2007Ingår i: Bostaden och kunskapen / [ed] Redaktionsrådet, Stiftelsen ARKUS, Stiftelsen ARKUS , 2007, s. 62-71Kapitel i bok, del av antologi (Övrig (populärvetenskap, debatt, mm))
  • 122543.
    Werner, Inga Britt
    KTH, Tidigare Institutioner, Infrastruktur.
    Preferenser beträffande bostadskvaliteter: olika konsumentgruppers bostadsval2003Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Samhällets finansiering av bostadsbyggandet har minskat radikalt. Nyproducerade bostäder erbjuds främst till kundgrupper med kapital. Därför är det viktigt att se på bostadsefterfrågan utgående från olika individers handlingsmöjligheter.

    I rapporten visas att hushållens livscykel bestämmer mycket av bostadspreferenser.Livsform, här utbildningsnivå och hemort, påverkar livscykelns skeenden. Livsstil är till stor del en produkt av livscykel och livsform. De grupper som har störst resurser har också störst möjlighet att utveckla livsstilar med betydelse för bostadsval.

    8 olika konsumentgrupper beskrivs, huvudsakligen ur Stockholmsperspektiv.

    Barnfamiljers starka önskan om småhus framträder, särskilt då andra barnet kommer. Högutbildade ensamstående kvinnor vill bo i innerstad nära kulturutbud, medan ensamstående män vill bo centralt ur kommunikationssynpunkt. De äldre par som säljer familjevillan har önskemål utöver sjönära bostadsrätt.

    Resultaten bidrar till att öka kunskapen också om de skiftande bostadsbehov som inte ger sig till känna på marknaden. Rapporten vänder sig till bostadssektorns byggherrar och till samhällsplanerare.

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  • 122544.
    Werner, Inga Britt
    KTH, Tidigare Institutioner, Arkitektur.
    Residents’ Environmentally Friendly Attitudes and Practices: – Motivation and Barriers in Different Forms Types of Tenure2004Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Thise paper presents an empirical study of actual households’ daily habits  and of their stated willingness for to adopt pro-environmental practices, relative to differ-ent forms of tenure. Economic incentives, linked to home-ownership, are shown to be significant in determining actions, as is perceived control. Well–-off homeowners have the highest frequency of pro-environmental behaviour, as measured in the study. Still, they cause the heaviest environmental impact, due to their larger dwellings and abundant car use. Households in multifamily housing have fewer incentives for and lower frequencies of pro-environmental habits, but cause less environmental impact due to their generally lower consumption. The results imply that the selection of target groups and the development of environmental policies need to be discussed assessed in relation to different life  styles and patterns of consumption.

  • 122545.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Residents’ Environmentally Friendly Attitudes and Practices: Motivation and Barriers in Different Types of Tenure2005Ingår i: Romanian Journal of Applied Psychology, ISSN 1454-8062, Vol. 6, nr 3-4, s. 136-146Artikel i tidskrift (Refereegranskat)
  • 122546.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Simulation of social processes: a new tool in housing research2005Ingår i: Methodologies in Housing Research / [ed] Vestbro, D-U; Hurol, Y ; Wilkinson, N, The Urban International Press , 2005, s. 258-271Kapitel i bok, del av antologi (Refereegranskat)
  • 122547.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Social Capital in Housing Management: The Concept as a Tool for Analysing Problems and Formulating Goals for Action2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    There is no formal social housing sector in Sweden, but municipally owned housing companies have aresponsibility to take on all kinds of tenants. That means that they are often in charge of housing areaswhere many low-income households live, with ensuing social problems. This paper is based upon a studyof management practices in such housing companies. ‘Social Capital’, a concept widely used in thediscussion on how to fight crime and deterioration in socially burdened housing areas, is employed in thetheoretical framework. Here the concept is used as well as describing local social networks as, in particular,‘bridging’ towards the surrounding society.The applied method is case study of the attempts of three housing companies to remedy problems such ashigh crime rate, bad reputation and low demand for housing units in certain areas.The results of the case studies showed that the companies’ different ways of addressing complex problemsinherent in the housing areas were not based upon any definition on how means were related to goals.They were more or less examples of trial and error. Only one of the companies did discuss intentionallyhow they should better the reputation of a certain housing area, by doing a selective physical upgrading ofcommunal spaces and the out-door environment. They were concerned to engage the residents in theprocess.The analysis employed a ‘what if’ - approach regarding the use of ‘Social Capital’ as a tool for thecompanies when analysing and addressing their problems. The discussion concludes in a review of theconcept ‘Social capital’ and some suggestions on how to make it operational in the practice of housingmanagement.

  • 122548.
    Werner, Inga Britt
    KTH, Tidigare Institutioner                               , Arkitekturskolan.
    Spelar kavlitet någon roll för priset?2000Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [sv]

    The purpose of the study is to show that architecturalquality in dwellings has an impact on purchase prices. This isperformed through an empirical investigation of 178 purchasesof flats in co-operative housing associations within GreaterStockholm. The studied dwellings are all in multifamilyhousing.

    The concept’architectural quality’is discussedand defined to match the purpose of the investigation. Thequalities of the dwellings have been rated according to fixedcriteria. Price data are asking prices from real estatebrokers’advertisements of sales.

    Investigation and analyses have been carried out by threedifferent methods:

        Statistical analysis in the form of multivariableregressions analysis, which required quantified measures ofquality.

        Enquiry to the buyers of the flats in the sample, ontheir evaluation of the qualities of the dwelling and theactual purchase price.

        Interviews with a small sample of buyers.

    Starting point for the analyses was a model for residentialchoice based upon location, dwelling area and payment to theco-operative housing association and the assumption thatdifferences in quality were of great importance for the finaldecision.

    The regression analyses did show that overall differences inarchitectural quality had significant impact on price in thesample of study objects.

    The enquiry showed that residents evaluated architecturalquality in common with the architect’s criteria, but thatthey also did evaluate many other forms of quality in adwelling before buying a flat. The balancing of differentqualities differed between buyers.

    Another result of the enquiry was data of purchase prices.Asking prices were a good estimation of market values, but theydid differ substantially from purchase price in some cases.

    The interviews increased the understanding of how differentcategories of buyers see and evaluate architectural quality.They also described which qualities in a dwelling that attractbuyers in their residential choice,

    As a whole the study has shown:

        It is possible to rate architectural quality inquantitative terms

        Residents and architects have many criteria in common intheir evaluation of architectural quality

        In the dwellings of the studied sample architecturalquality had an impact on price amounting to 10-15 %

    Key Concepts: Architectural Quality; Co-operativeHousing; Evaluation of Quality; Hedonic Prices; Model forResidential Choice; Quantified Measures of Quality; RegressionAnalysis

  • 122549.
    Werner, Inga Britt
    KTH, Tidigare Institutioner (före 2005), Arkitektur.
    Spelar kvalitet någon roll för priset?: en studie av bostadsrättsköp i Storstockholm2000Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The purpose of the study is to show that architectural quality in dwellings has an impact on purchase prices. This is performed through an empirical investigation of 178 purchases of flats in co-operative housing associations within Greater Stockholm. The studied dwellings are all in multifamily housing.

    The concept ’architectural quality’ is discussed and defined to match the purpose of the investigation. The qualities of the dwellings have been rated according to fixed criteria. Price data are asking prices from real estate brokers’ advertisements of sales.

    Investigation and analyses have been carried out by three different methods:

    • Statistical analysis in the form of multivariable regressions analysis, which required quantified measures of quality.
    • Enquiry to the buyers of the flats in the sample, on their evaluation of the qualities of the dwelling and the actual purchase price.
    • Interviews with a small sample of buyers.

    Starting point for the analyses was a model for residential choice based upon location, dwelling area and payment to the co-operative housing association and the assumption that differences in quality were of great importance for the final decision.

    The regression analyses did show that overall differences in architectural quality had significant impact on price in the sample of study objects. The enquiry showed that residents evaluated architectural quality in common with the architect’s criteria, but that they also did evaluate many other forms of quality in a dwelling before buying a flat. The balancing of different qualities differed between buyers.

    Another result of the enquiry was data of purchase prices. Asking prices were a good estimation of market values, but they did differ substantially from purchase price in some cases.

    The interviews increased the understanding of how different categories of buyers see and evaluate architectural quality. They also described which qualities in a dwelling that attract buyers in their residential choice, As a whole the study has shown:

    - It is possible to rate architectural quality in quantitative terms

    - Residents and architects have many criteria in common in their evaluation of architectural quality

    - In the dwellings of the studied sample architectural quality had an impact on price amounting to 10-15 %

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  • 122550.
    Werner, Inga Britt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Sweden2017Ingår i: Sustainable Communities and Urban Housing: A comparative European perspective / [ed] Pareja-Eastaway, Montserrat; Winston, Nessa, Abingdon, Oxon;New York, NY: Routledge, 2017, 1, s. 55-73Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Sweden has a high sustainability index according to international comparisons. The Swedish policies regarding sustainability in housing focus energy consumption. These policies are relatively effective and broadly accepted, like f. ex. a number of targeted subsidies which have enhanced property owners’ investment in energy saving technology (heat-pumps, district heating….). The urban environment is generally healthy, as a result of regulations of urban planning. Housing quality is high, although differences are increasing.

    This growing gap of housing quality is driven by rising prices and affordability issues. Higher income households often ‘over-consume’ dwelling space, as transaction costs are high due to the rise of house prices plus taxes on the revenue from realisation of the current house value. The main part of new housing production is aiming at the upper end of the market for ownership tenure. Young, low income households have a steep entry to the housing market, as vacant affordable rental units are few. The distribution of dwelling space is uneven, as is security of tenure and housing costs.

    The pending challenge is an overheated housing market, where house prices are steadily rising. After deregulation of the former more controlled housing market, housing production has been slow to increase. Swedish households are on average indebted up to a level of 175 % of their net income (among the more debt laden European, source Riksbanken – The National Swedish Bank). This is a threatening home-made crisis. Swedish housing offers many high quality buildings and infrastructure designed to defer/postpone the climate change, but the immediate social demand of a higher supply of affordable dwellings is yet to be solved.

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