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  • Public defence: 2016-10-25 10:00 F3, Stockholm
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Toward a reliability framework for the observational method2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Constructing sustainable structures in rock that satisfy all predefined technical specifications requires rational and effective construction methods. When the geotechnical behaviour is hard to predict, the Euro­pean design code, Eurocode 7, suggests application of the observational method to verify that the performance is acceptable. The basic principle of the method is to accept predefined changes in the design during con­struction to comply with the actual ground conditions, if the current de­sign is found unsuitable. Even though this in theory should ensure an effective design solution, formal application of the observational method is rare.

    Investigating the applicability of the observational method in rock en­gineering, the aim of this thesis is to identify, highlight, and solve the aspects of the method that limit its wider application. Furthermore, the thesis aims to improve the conceptual understanding of how design deci­sions should be made when large uncertainties are present.

    The main research contribution is a probabilistic framework for the observational method. The suggested methodology allows comparison of the merits of the observational method with that of conventional design. Among other things, the thesis also discusses (1) the apparent contradiction between the preference for advanced probabilistic calculation methods and sound, qualitative engineering judgement, (2) how the establishment of limit states and alarm limits must be carefully considered to ensure structural safety, and (3) the applicability of the Eurocode defini­tion of the observational method and the implications of deviations from its principles.

  • FAHIMIFAR, FARAZ
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    FAHIMIFAR, FARAZ
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    BananaCharge - electricity on the go2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this bachelor's thesis a product was developed gradually from idea to reality using methods in technical design. The final product is called " Banana Charge" whose purpose is to provide the Swedish people with a convenient solution for charging their portable products (mainly mobile phones) on the go, without having to be limited to a socket. Up to 30 percent of Stockholm residents are willing to pay for a service that provides their mobiles with power when they are in need. The expansion of cities allows people to travel longer distances from point A to B, which means that people do not always have time to recharge their mobile device at home. BananaCharges want to solve this problem by placing a number of these stations around Stockholm, therefore they started this project where the aim is to place numerous unmanned charging stations at key locatons.

    At the start of the project a feasibility study was conducted to gain wider knowledge of unattended stations, this was performed in Central station Stockholm. A customer survey started once the feasibility study was conducted, the station was adapted according to the customer requirements. This was followed by a competitive analysis to find the existing "state of the art ' solutions on the market today. Competition analysis resulted in Mobilequbes being today's " state of the art " solution and became a reference point for Banana Charge during the project.

    The method of "black box" was used to clarify what the station's task is and how to go about solving those tasks. Wireless charging was selected as a final solution (based on the method  of "black box") where " state of the art " products were used. Several methods were used in the concept development process including shape- and structural variations and morphological matrix. Banana Charge eventually chose three concepts to continue with.

    The three concepts were evaluated during the concept evaluation phase with the help ofseveral methods among them was eliminate matrix and relative decision matrix, this resulted to concept 3 being selected which followed the customer requirements best. The concept was named Banana Charge (alpha) and was improved during the concept development process.

    Each problem area was noted down during the development process and was analyzed,  theproblem where solved after prototyping and testing each component, the results gave a working mechanism located in a well-designed station. The final design was dimensioned with the help of tools such as Solid Edge and Matlab, a cost analysis was done on all of the parts after contacting retailers

    It was concluded that the construction of the station is possible but it will cost more than the desired production cost, a deeper cost estimate can be made with a volume-based cost. The stepper motor for the mechanism should be replaced with a servomotor for more precise movement or an encoder could be attached for more precision, a rubber mat could be used to increase the friction in the sliding track. Finally, it can be discussed if a more precise definition of the workload should have been done when the locking mechanism, the station and the battery mechanism was too much work for the short time span.

  • GHADAMGAHI, MERSEDEH
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Energy and Furnace Technology.
    GHADAMGAHI, MERSEDEH
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Energy and Furnace Technology.
    Mathematical Modelling of Combustion and Heat Transfer inside a Soaking Pit Furnace2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Operating conditions of the furnaces has the major effect on the quality of steel during steel production process. Furnaces also are the biggest energy consumer in the whole production process  which make them a center of concern, in order to get to the most optimized condition through both energy and quality aspects.

    Soaking pit furnaces are for heating steel ingots before rolling, in order to provide convenient conditions for ingots for further procedures. These batch furnaces are characterized by heat and temperature conditions that vary in time. The structure permits rapid heating of the metal inside the furnace, since heat is supplied over the entire surface of the ingot.

    One serious problem that these furnaces might contain is the existence of non-uniform temperature gradient inside the chamber that causes different temperature distribution on the ingots surface which leads to a bad surface quality of them, considering further rolling process.

    As the first step through obtaining the best temperature gradient inside the chamber, is to ensure the exact temperature condition in the current running procedure. In here as the first step through the problem solving of these furnaces, temperature profile, radiation profile and other effective parameters are investigated with the aid of CFD software.

    The simulation is done by ICEM and FLUENT programs for geometry and mesh designing, and modeling in respect.

    Modeling is based on four main steps:

            I.            Modeling of the furnace chamber geometry and applying appropriate mesh style with ICEM

          II.            Modeling the chamber with fluent, and taking the results (case 0)

        III.            Modeling of six cases with different excess air, in order to investigate the best λ magnitude

        IV.            Modeling of six cases with different burner capacities in order to investigate its affection on combustion parameters

  • Public defence: 2016-10-21 10:00 Gard-aulan, Solna
    Periyannan Rajeswari, Prem Kumar
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Periyannan Rajeswari, Prem Kumar
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Droplet microfluidics for single cell and nucleic acid analysis2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Droplet microfluidics is an emerging technology for analysis of single cells and biomolecules at high throughput. The controlled encapsulation of particles along with the surrounding microenvironment in discrete droplets, which acts as miniaturized reaction vessels, allows millions of particles to be screened in parallel. By utilizing the unit operations developed to generate, manipulate and analyze droplets, this technology platform has been used to miniaturize a wide range of complex biological assays including, but not limited to, directed evolution, rare cell detection, single cell transcriptomics, rare mutation detection and drug screening.

    The aim of this thesis is to develop droplet microfluidics based methods for analysis of single cells and nucleic acids. In Paper I, a method for time-series analysis of mammalian cells, using automated fluorescence microscopy and image analysis technique is presented. The cell-containing droplets were trapped on-chip and imaged continuously to assess the viability of hundreds of isolated individual cells over time. This method can be used for studying the dynamic behavior of cells. In Paper II, the influence of droplet size on cell division and viability of mammalian cell factories during cultivation in droplets is presented. The ability to achieve continuous cell division in droplets will enable development of mammalian cell factory screening assays in droplets. In Paper III, a workflow for detecting the outcome of droplet PCR assay using fluorescently color-coded beads is presented. This workflow was used to detect the presence of DNA biomarkers associated with poultry pathogens in a sample. The use of color-coded detection beads will help to improve the scalability of the detection panel, to detect multiple targets in a sample. In Paper IV, a novel unit operation for label-free enrichment of particles in droplets using acoustophoresis is presented. This technique will be useful for developing droplet-based assays that require label-free enrichment of cells/particles and removal of droplet content. In general, droplet microfluidics has proven to be a versatile tool for biological analysis. In the years to come, droplet microfluidics could potentially be used to improve clinical diagnostics and bio-based production processes.

  • Public defence: 2016-10-14 13:00 T 1 (Emmy Rappestad), Huddinge
    Lagerstedt, Marianne
    KTH, School of Technology and Health (STH).
    Lagerstedt, Marianne
    KTH, School of Technology and Health (STH).
    Mot nätverkssjukvård i komplex miljö: - behov av en vetenskaplig syn på ledning för säker vård och effektiv resursanvändning2016Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Since 2008 advanced home healthcare agencies (ASiH) in a larger Swedish county council has underwent a transformation, to become part of a coming concept: networked healthcare (NVS). NVS means that intermediate multi-organizational healthcare (IMV) will be produced often in the home, and from 2013 to an increasing number of patients in different age groups with different diagnoses and medical conditions - in large variability of needs. At the same time IMV has proved to be not simply practical to implement in a resource-efficient and patientsafe way. Based on theories from Command and Control Science the safetyproblem that arise in connection with IMV is a sign of the less known increasing need of the direction and coordination support that IMV requires.

    With a casestudy based research approach with interactive elements, different qualitative methods has been used in two phases between 2008 - 2013. The first phase is characterized by a phenomenological approach, while the second phase has a critical hermeneutic approach. Research methods includes fieldvisits with informal discussions, in-depth interviews, validation with respondents and two different methodologies for textanalysis.

    The main result shows that practical aggravating circumstances for safe care consists of lesser known and from 2013 increasing problems with direction and coordination, through expanded advanced IMV in the home as a part of NVS concept. This also as a result of inadequate and inappropriate direction and coordination support for IMV.

    The thesis concludes that the NVS represents a resource intensive health care concept, which requires a new view on the management issue and a network-related methodology for direction and coordination. This is to promote ethical, equitable, patientsafe and dignified advanced IMV so an optimized use of resources can be implemented, through shared responsibility and coordination in patientuniquely designed networkconstellations as a given work model.

  • Liljefors, Pontus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Liljefors, Pontus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Social sustainability in Swedish urban development - what does it mean?: A casestudy of three Citylab Action pilot projects2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cities around the world are facing challenges of rapid population growth, social inequality, environmental degradation and climate change. Within the realm of planning and policy, one answer to these issues has been the invention of certification systems to support the transition to a sustainable urban development. In the last ten years a number of certification systems for sustainable urban development on neighbourhood level have been developed, such as BREEAM Communities and LEED Neighborhood Development. Though an important contribution for a systematic way to treat sustainability in urban development, such systems have been criticised in a number of criteria, among which an important deficiency is their lack of factors for social sustainability.

    A new Swedish certification system for neighbourhood level, Citylab Action, is since January 2016 being tested in a pilot round with twelve Swedish urban development projects. The aim of this study was therefore to investigate how three of the pilot projects worked with social sustainability and within which areas the Citylab Action Guide best could be developed to support socially sustainable urban development. The following research questions were formulated:

    1. What is a relevant understanding of social sustainability for contemporary urban development drawing on the academic literature?
    2. How do the selected Citylab Action projects understand and work with social sustainability? What are projects’ key challenges for creating socially sustainable neighbourhoods?
    3. What are the projects’ experiences with Citylab Action in relation to their work with social sustainability?

    The thesis had a critical approach and took ground in a literature study, which rendered an analytical framework and the normative standpoint that social sustainability needs to be concerned with increasing social justice. Täby Park, DrottningH and Masthuggskajen were selected as cases, and studies involved interviews with two civil servants from each project and analysis of planning documents related to the projects’ work with social sustainability. An analysis of the empirical material was carried out underpinned by the analytical framework, which contained the questions:

    • How is social sustainability (implicitly) defined and operationalised?
    • How is the project oriented in regards to the dualism of development and maintenance?
    • Who is considered in the development of the district?

    Results showed theoretical understanding of social sustainability, as well as operational work, were very different between projects. Synthesis suggests a key challenge for the projects’ work with social sustainability concerns the tendency of marginalising people with less purchasing power. For the development of the Citylab Action Guide to better support socially sustainable urban development, four proposals are given. The Guide should include:

    1. more aspects for how to work with existing inhabitants,
    2. more distinct aims for projects to execute a comprehensive analysis of the effects on segregation patterns,
    3. more attention to the creation of affordable apartments and socially mixed housing, and
    4. aims for considering the seven discrimination grounds and socio-economic status in the outcomes of planning.
  • Public defence: 2016-09-30 10:05 Sal B2, Stockholm
    Döse, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures. CBI Betonginstitutet.
    Döse, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures. CBI Betonginstitutet.
    Ionizing Radiation in Concrete and Concrete Buildings: Empirical Assessments2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of the major issues with radiation from the natural isotopes 40K, 226Ra (238U) and 232Th and their decay products is the forthcoming legislation from the European Commission in relation to its Basic Safety Directive (2014). The European legislation is mandatory and could not be overthrown by national legislation. Hence, even though the BSS is still a directive it is foreseen as becoming a regulation in due time.

    The reference value of the natural isotopes, from a radiation point of view, set for building materials is 1 mSv per year (EC, 2014). Earlier recommendations (The Radiation Protection Authorities in Denmark, Finland, Iceland, Norway and Sweden, 2000) within the Nordic countries set an upper limit at 2 mSv per year of radiation from building materials.

    The main objective within the frame of the thesis was to investigate gamma radiation in relation to Swedish aggregates and their use as final construction products and the applicability and use of a model (EC, 1999) for building materials to calculate the effective dose within a pre-defined room. Part of the thesis also investigates different methodologies that can be used to assess the radiation in a construction material made up of several constituents (building materials) and aims to show that for some purposes as for the construction industries (precast concrete), that a hand-held spectrometer can be used with good accuracy, even though the object is limited in thickness and size. Secondly, the author proposes a simplified way of assessing the radiation in a construction material by use of correlation coefficient of a specified recipe by use of a hand-held spectrometer. Moreover, an understanding of the different building materials´ contribution to the finalized construction product, e.g. concrete is demonstrated, and how to achieve a good control of the radiation levels in the concrete building.

  • Welander, Jesper
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematical Statistics.
    Welander, Jesper
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematical Statistics.
    Forecasting foreign exchange rates with large regularised factor models2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Vector autoregressive (VAR) models for time series analysis of high-dimensional data tend to suffer from overparametrisation as the number of parameters in a VAR model grows quadratically with the number of included predictors. In these cases, lower-dimensional structural assumptions are commonly imposed through factor models or regularisation. Factor models reduce the model dimension by projecting the observations onto a common lower-dimensional subspace, decomposing the variables into common and idiosyncratic terms, and might be preferred when predictors are highly collinear. Regularisation reduces overfitting by penalising certain features of the model estimates and might be preferred when, for example, only a few predictors are assumed important.

    We propose a regularised factor model where factors are constructed by projection onto a common subspace and where the transition matrices in a time series model with the resulting factors are estimated with regularisation. By the subspace estimation we hope to uncover underlying latent factors that explain the predictor dynamics and the additional penalisation is used to encourage additional sparsity and to impose a priori structural knowledge into the estimate. We investigate unsupervised and supervised subspace extraction and extend earlier results on dynamic subspace extraction. Additionally, we investigate element-wise regularisation by the ridge and lasso penalties and two extensions of the lasso penalty that encourage structural sparsity. The performance of the model is tested by forecasting log returns of exchange rates.  

  • Heimbürger, Hjalmar
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematical Statistics.
    Heimbürger, Hjalmar
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematical Statistics.
    Modelling of Stochastic Volatility using Partially Observed Markov Models2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, calibration of stochastic volatility models that allow correlation between the volatility and the returns has been considered. To achieve this, the dynamics has been modelled as an extension of hidden Markov models, and a special case of partially observed Markov models. This thesis shows that such models can be calibrated using sequential Monte Carlo methods, and that a model with correlation provide a better fit to the observed data. However, the results are not conclusive and more research is needed in order to confirm this for other data sets and models.

  • Public defence: 2016-10-14 14:00 Sal M108, Stockholm
    Wang, Cong
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Wang, Cong
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Optimal Design of District Energy Systems: a Multi-Objective Approach2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis is to develop a holistic approach to the optimal design of energy systems for building clusters or districts. The emerging Albano university campus, which is planned to be a vivid example of sustainable urban development, is used as a case study through collaboration with the property owners, Akademiska Hus and Svenska Bostäder. The design addresses aspects of energy performance, environmental performance, economic performance, and exergy performance of the energy system. A multi-objective optimization approach is applied to minimize objectives such as non-renewable primary energy consumptions, the greenhouse gas emissions, the life cycle cost, and the net exergy deficit. These objectives reflect both practical requirements and research interest. The optimization results are presented in the form of Pareto fronts, through which decision-makers can understand the options and limitations more clearly and ultimately make better and more informed decisions. Sensitivity analyses show that solutions could be sensitive to certain system parameters. To overcome this, a robust design optimization method is also developed and employed to find robust optimal solutions, which are less sensitive to the variation of system parameters. The influence of different preferences for objectives on the selection of optimal solutions is examined. Energy components of the selected solutions under different preference scenarios are analyzed, which illustrates the advantages and disadvantages of certain energy conversion technologies in the pursuit of various objectives. As optimal solutions depend on the system parameters, a parametric analysis is also conducted to investigate how the composition of optimal solutions varies to the changes of certain parameters. In virtue of the Rational Exergy Management Model (REMM), the planned buildings on the Albano campus are further compared to the existing buildings on KTH campus, based on energy and exergy analysis. Four proposed alternative energy supply scenarios as well as the present case are analyzed. REMM shows that the proposed scenarios have better levels of match between supply and demand of exergy and result in lower avoidable CO2 emissions, which promise cleaner energy structures.

  • Kilkis, Siir
    et al.
    Kilkis, Siir
    Wang, Cong
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Björk, Folke
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Martinac, Ivo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Cleaner energy supply structures for campus building clustersManuscript (preprint) (Other academic)
    Abstract [en]

    The comparison of building clusters based on energy and the quality of energy (exergy) is a

    key aspect for determining steps towards cleaner energy supply structures. This paper

    compares two building clusters based on an integrated approach that involves building and

    energy system level analyses. The first cluster involves 8 buildings with diverse energy profiles

    at the KTH Royal Institute of Technology campus, including faculty buildings, laboratories, and

    a data center with waste heat recovery. The second cluster involves planned buildings in the

    Albano district in the vicinity of the KTH campus that will be a joint area with lecture buildings

    and accommodation for 3 universities in Stockholm. The present energy supply structure for

    the campus and the surrounding urban area includes a local combined heat and power (CHP)

    plant. The comparison of the building clusters involve analyses based on the Rational Exergy

    Management Model. Four scenarios, which involve different shares for the existing CHP units,

    new biofuel CHP unit, seawater heat pumps, peak load boilers, electric boilers, large scale

    aquifer thermal energy storage, heat supply from solar collectors, and electricity and heat from

    photovoltaic thermal arrays are devised for comparison. The scenarios have at most an exergy

    match of 0.81. The paper concludes with useful results that are in line with the aims of IEA

    Annex 64 on Optimised Performance of Energy Supply Systems with Exergy Principles.

  • Döse, Magnus
    KTH, School of Architecture and the Built Environment (ABE). CBI Betonginstitutet AB.
    Döse, Magnus
    KTH, School of Architecture and the Built Environment (ABE). CBI Betonginstitutet AB.
    Risk Assessment of Swedish Concrete as a Construction Material in Relation to Naturally Occurring Radiation from Different Aggregates2014In: / [ed] Giorgio Lollino,Andrea Manconi,Fausto Guzzetti,Martin Culshaw,Peter Bobrowsky,Fabio Luino, Springer , 2014Conference paper (Refereed)
  • Wang, Cong
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Wang, Cong
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Martinac, Ivo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Magny, Alessandro
    Multi-objective robust optimization of energy systems for a sustainable district in Stockholm2015Conference paper (Other academic)
    Abstract [en]

    This paper applies a multi-objective robust design optimization approach to the energy system design of a sustainable district. The life cycle cost and the greenhouse gas emissions are the two objectives that are minimized. In order to investigate the possbility to implement a nearly zero energy district, the nonrenewable primary energy consumption is kept below a certain value, handled as a constraint in the optimization. Through the proposed robust design optimization methodology, the robust Pareto optimal solutions are obtained, which are less sensitive than the deterministic ones to the uncertainties assumed in the selected most influential economic and technical paramers as well as design variables.

  • Wang, Cong
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Wang, Cong
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Martinac, Ivo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Magny, Alessandro
    Multi-objective optimization of energy system designs for the Albano university campus in Stockholm2016Conference paper (Other academic)
    Abstract [en]

    In this paper, a multi-objective optimization approach based on genetic algorithm is applied to the energy system design of a sustainable district – the new Albano university campus in Stockholm. The study aims to help district planners find optimal energy solutions that have good energy, environmental and economic performances. Three objectives are minimized: the non-renewable primary energy consumption, the greenhouse gas emissions, and the levelized life cycle cost. A wide range of energy conversion technologies and energy sources including both renewables and non-renewables have been modeled. The potential to recover waste heat from greywater and a prospective IT/Data center is analyzed. The energy system is modelled in steady-state and simulated in an hourly resolution with renewable energy production determined at real time. The optimization results are presented in the form of Pareto fronts, which helps district planners understand more clearly the trade-off between conflicting objectives and make more informed decisions.

  • Bidadfar, Ali
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Bidadfar, Ali
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Monadi, Mehdi
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Decoupled voltage stability assessment of distribution networks using synchrophasors2016Conference paper (Refereed)
  • Urhammar, Henrik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Urhammar, Henrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Ahmed, Ahmed
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Kommunernas arbetssätt med underhåll av VA-ledningar: Granskning och jämförelse2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Public defence: 2016-10-14 14:00 Kollegiesalen, Stockholm
    Karlsson, Caroline
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Karlsson, Caroline
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Geo-environmental considerations in transport infrastructure planning2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Transport infrastructure constitutes one of the key factors to a country’s economic growth. Investment in new transport infrastructure might cause potential environmental impacts, and if a project has several alternative corridors open for suggestion then each alternative corridor will have a different impact on the environment. The European Commission has stated that the natural resources are important to the quality of life. Therefore, the efficient use of resources will be a key towards meeting future climate change and reduction in greenhouse gas (GHG) emissions. This implies that in an evergrowing global society the resource efficiency as well as the choice of transport infrastructure corridor becomes even more important to consider. The aim of this research project was to contribute to early transport infrastructure planning by the development of methods for and implementation of easy understandable geological criteria and models for decision support. Moreover, the intention was to assess how geological information can be developed and extracted from existing spatial data and coupled with other areas of interest, such as ecology and life cycle assessment. It has previously been established that geological information plays an important role in transport infrastructure planning, as the geological characteristics of the proposed area as well as the possibilities of material use influences the project. Therefore, in order to couple geological information for early transport infrastructure planning, four studies (Paper I-IV) were undertaken where methods were developed and tested for the inclusion of geological information. The first study (Paper I) demonstate how optional road corridors could be evaluated using geological information of soil thickness, soil type and rock outcrops, bedrock quality and slope in combination with ecological information. The second study (Paper II) shows how geological information of soil thickness and stratigraphy can be combined with life cycle assessments (LCA) to assess the corresponding greenhouse gas emission and energy use for the proposed road corridors. The difficulty of using expert knowledge for susceptibility assessment of natural hazards, i.e. flooding, landslide and debris flow, for early transport infrastructure planning was presented in the third study (Paper III). In this study the expert knowledge was used in a multi-criteria analysis where the analytic hierarchy process (AHP) was chosen as a decision rule. This decision rule was compared to the decision rule weighted linear combination (WLC) using two different schemes of weighting. In all the mentioned studies the importance of soil thickness information was highlighted. Therefore, the fourth and final study (Paper IV) presented a new methodology for modelling the soil thickness in areas where data is sparse. A simplified regolith model (SRM) was developed in order to estimate the regolith thickness, i.e. soil thickness, for previously glaciate terrain with a high frequency of rock outcrops. SRM was based on a digital elevation model (DEM) and an optimized search algorithm. The methods developed in order to couple geological information with other areas of interest is a tentative step towards an earlier geo-environmental planning process. However, the methods need to be tested in other areas with different geological conditions. The combination of geological information in GIS with MCA enabled the integration of knowledge for decision making; it also allowed influencing the importance between various aspects of geological information as well as the importance between geological information and other fields of interest, such as ecology, through the selected weighting schemes. The results showed that synergies exist between ecology and geology, where important geological considerations could also have positive effects on ecological consideration. Soil thickness was very important for GHG emission and energy whereas stratigraphical knowledge had a minor influence. When using expert knowledge the consistency in the expert judgements also needs to be considered. It was shown that experts tended to be inconsistent in their judgements, and that some consistency could be reached if the judgements were aggregated instead of used separately. The results also showed that the developed SRM had relatively accurate results for data sparse areas, and that this model could be used in several projects where the knowledge of soil thickness is important but lacking. It was concluded that geological information should be considered. By using GIS and MCA it is possible to evaluate different aspects of geological information in order to improve decision making.

  • Public defence: 2016-10-21 10:00 F3, Stockholm
    Farooqui, Maaz
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Farooqui, Maaz
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Innovative noise control in ducts2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The objective of this doctoral thesis is to study three different innovative noise control techniques in ducts namely: acoustic metamaterials, porous absorbers and microperforates. There has been a lot of research done on all these three topics in the context of duct acoustics. This research will assess the potential of the acoustic metamaterial technique and compare to the use of conventional methods using microperforated plates and/or porous materials. 

    The objective of the metamaterials part is to develop a physical approach to model and synthesize bulk moduli and densities to feasibly control the wave propagation pattern, creating quiet zones in the targeted fluid domain. This is achieved using an array of locally resonant metallic patches. In addition to this, a novel thin slow sound material is also proposed in the acoustic metamaterial part of this thesis. This slow sound material is a quasi-labyrinthine structure flush mounted to a duct, comprising of coplanar quarter wavelength resonators that aims to slow the speed of sound at selective resonance frequencies. A good agreement between theoretical analysis and experimental measurements is demonstrated.

    The second technique is based on acoustic porous foam and it is about modeling and characterization of a novel porous metallic foam absorber inside ducts. This material proved to be a similar or better sound absorber compared to the conventional porous absorbers, but with robust and less degradable properties. Material characterization of this porous absorber from a simple transfer matrix measurement is proposed.The last part of this research is focused on impedance of perforates with grazing flow on both sides. Modeling of the double sided grazing flow impedance is done using a modified version of an inverse semi-analytical technique. A minimization scheme is used to find the liner impedance value in the complex plane to match the calculated sound field to the measured one at the microphone positions.

  • Brandner, Hanna
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    Brandner, Hanna
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    Idenitfying the Influential Factors of the Temporal Variation of Water Consumption: A Case Study using Multiple Linear Regression Analysis2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is a part of the water development project conducted by Svenskt Vatten, which is the Swedish Water and Wastewater Association (SWWA) as well as Tyréns, a consultancy company with offices based in Stockholm, Sweden. Prior to this thesis work, a quality assessment was conducted for some of the locations provided by municipalities in Sweden. This thesis builds upon the revised water consumption data, and also continues to work with validating and modifying the water measurement data in order to proceed with the next step of the water development project, which is to identify any trends in the temporal variation of water consumption. The main objective of this thesis work is to investigate the influence of climatic, time-related and categorical factors on water consumption data collected for different regions in Sweden, and includes a number of different sectors such as residential, industrial and agricultural water user sectors. For the analysis of data, spectral analysis and sinusoidal modelling will be applied in order to find the periodicity of the data, and then simulate the fitted sinusoidal equation to the observed water consumption data for the hourly interval period. Multiple linear regression analysis is then used to assess what independent variables such as climate, time-related and categorical variables can explain the variation in water consumption over hourly and daily periods of time. 

    Spectral analysis identifies high peaks in the spectral density of the data at 12 and 24 hour cycles, for the hourly water consumption data. For the total daily consumption of water, there is a peak at 7 days, which clarifies that there is a weekly pattern occurring throughout the year. The results from the simple linear regression analysis, where the linear relationship between temperature and water consumption was determined, reveals that the water consumption tends to increase within an increasing temperature, where in Lönashult, Alvesta municipality the water demand increased by 5.5% with every 2 ºC rise in temperature, at a threshold of 12 ºC. For Kalix municipality the three areas selected have around 1-2 % increase in water demand with every 2 ºC rise in temperature for the period of May to December. In Gothenburg, areas that were mixed villa areas or areas with summer homes there was a rise of around 2-12 % in water demand, however areas that are situated in the inner city Gothenburg, or that have majority student housing, the water consumption tends to decrease by 2-7% in water demand with every 2 ºC rise in temperature, with a threshold of 12 ºC.

    In multiple regression analysis, the hourly water consumption results in adjusted R2 values were in the range from 0.58 to 0.87 (58-87%) for the best model approach and therefore has a significant relationship between water consumption and the explanatory variables chosen for this study. For the daily water consumption, the adjusted R2 values were in the range of 0.22-0.83 (22-83%).  The adjusted R2 values are lower for certain areas and can be explained by a number of factors, such as the different variables used for the daily water consumption analysis, as variables that explain more the periodicity of the data such as the sinusoidal fitted variable and hourly or night/day changes in consumption are not included. As well as this, not all independent variables such as the climate variables were available or complete for particular time periods, and also errors in the data can lead to a significantly lower R2 value. 

  • Khachlouf, Rayen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Khachlouf, Rayen
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Ahmed, Shakrin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Massivträ och dess miljöpåverkan2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Rappne, Mattias
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Rappne, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Özpakmezci, Ali
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Möjligheter med modulbostäder för nyanlända2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Baltzer, Sigrid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Baltzer, Sigrid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Bühlmann, Axel
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Så bygger vi bättre studentbostäder: Bostäder efter studenterns behov2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Hägg, Elias
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hägg, Elias
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Kanarbik, Emil
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Daglig materialkontroll: Mot färre dagliga leveranser och ett säkrare materialflöde2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Isacsson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Isacsson, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Muscle to motor communication2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study is to examine the parameters influencing the signal to noise ratio in surface electromyography as well as the signals usability as a means of control in mechatronical applications. Electromyography refers to the electrical signals detected in the muscles during activation. Receiving a reliable signal presents a number of challenges as the signals are to their nature very weak. There is also a large amount of ambient noise which will drown the signal if left unprocessed. Removal of the noise was performed by using a series of amplifiers and filters to gradually increase the signal to noise ratio. The processed signal was forwarded to a microcontroller for posttreatment, calculation and presentation. A demonstrator was built in order to underline the validity of the theory presented in the report.

    The project resulted in a fully functional circuit for registering sEMG-signals and forwarding them to an Arduino microcontroller. The signal to noise ratio was satisfactory given the scope of the project. The motor-control using the signal as reference was also successfully performed. In sum, this points towards that sEMG is a strong option for a control signal in mechatronical applications already at a small-scale level of integration.

  • Bresin, Roberto
    et al.
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Bresin, Roberto
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Elblaus, Ludvig
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Frid, Emma
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Favero, Federico
    KTH, School of Architecture and the Built Environment (ABE).
    Annersten, Lars
    Musikverket.
    Berner, David
    Musikverket.
    Morreale, Fabio
    Queen Mary University of London.
    SOUND FOREST/LJUDSKOGEN: A LARGE-SCALE STRING-BASED INTERACTIVE MUSICAL INSTRUMENT2016In: Sound and Music Computing 2016, SMC Sound&Music Computing NETWORK , 2016, 79-84 p.Conference paper (Refereed)
    Abstract [en]

     In this paper we present a string-based, interactive, largescale installation for a new museum dedicated to performing arts, Scenkonstmuseet, which will be inaugurated in 2017 in Stockholm, Sweden. The installation will occupy an entire room that measures 10x5 meters. We aim to create a digital musical instrument (DMI) that facilitates intuitive musical interaction, thereby enabling visitors to quickly start creating music either alone or together. The interface should be able to serve as a pedagogical tool; visitors should be able to learn about concepts related to music and music making by interacting with the DMI. Since the lifespan of the installation will be approximately five years, one main concern is to create an experience that will encourage visitors to return to the museum for continued instrument exploration. In other words, the DMI should be designed to facilitate long-term engagement. Finally, an important aspect in the design of the installation is that the DMI should be accessible and provide a rich experience for all museum visitors, regardless of age or abilities.

  • Shahinyan, Hayk
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Shahinyan, Hayk
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    HIMA ! Revolutionary Park in Yerevan, Armenia2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    HIMA! / NOW! - translation from Armenian

    In light of recent and ongoing protests, demonstrations and riots in Ukraine, Egypt, Israel or Armenia, some actual questions arise such as how is the built environment used as an area of protest, how it is chosen as a focal point or path for resistance, what are the common characteristics of revolutionary spaces and how the environment effects on success.

    Lack of democracy from the government and in everyday life of Armenia society, total corruption and feeling of impunity oligarchy, the government and most of governmental institutions, weak economic growth accompanied by alarming number of emigration as well as successful scenarios in neighboring Georgia and Ukraine, force to predict a inescapable eruption of protests Armenia in near future. History shows that protests and civil disobedience are inevitable and necessary expressions of dissent in any democratic nation and country.

    However there are different passive tools to improve democratic institutions in the society and country in general such as public forums, open discussions and debates, freedom of speech and media etc.

    With this project I want to create a great Park with generous program embracing main democratic principles as a Public Space and Forum for everyone in capital of Armenia, Yerevan, BUT in case of nascent civil resistance the Park will become a space as a tool with urban inventory that people can use, manipulate, claim in order to defend their values and save own life's.

    This will be a Playground/Fortress for Democracy !

  • Fredberg, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Fredberg, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Processen i komplexa byggnadsprojekt2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Arbetet bakom komplexa husbyggnadsprojekt. 

  • Aripov, Alim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Aripov, Alim
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Shirvanpour, Shaian
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Bygglogistik metoder: En granskning av norra Djurgårdsstaden och Barkarbystaden2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Berglund, Elin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Berglund, Elin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Spansk, Lina
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Bostadshyresmarknaden i Stockholms län: Marknadsundersökning av Stockholms läns hyresmarknad och dess framtida intresse av en ny marknadsplats2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • Paul, Ruma
    et al.
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS. Université catholique de Louvain, Belgium .
    Paul, Ruma
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS. Université catholique de Louvain, Belgium .
    Van Roy, Peter
    Université catholique de Louvain, Belgium .
    Building Distributed Applications for Stressful Environments using Reversibility and Phase-Awareness2016In: 2016 Conference on Complex Systems, 2016Conference paper (Refereed)
    Abstract [en]

    Large-scale applications for mobile devices and Internet of Things live in stressful real-world environments: they have both continuous faults and bursts of high faults. Typical faults are node crashes, network partitions, and communication delays. We give a principled way to build applications that survive in such environments by using the concepts of Reversibility and Phase [1].  A system is Reversible if the set of operations it provides depends on its current fault rate and not on the history of the fault rate.  Reversibility generalizes standard fault tolerance with nested fault models.  When the fault rate goes outside one model then it is still inside the next model.  Phase is a per-node property that gives a qualitative indication of what system operations are available at each node, given the current fault rate.  Phase can be determined with no additional distributed computation. We present two case studies.  First, we present a transactional key-value store built on a structured overlay network and we explain how to make it Reversible [2].  Second, we present a distributed collaborative graphic editor built on top of the key-value store, and we explain how to make it Phase-Aware, i.e., it optimizes its behavior according to a real-time observation of phase at each node using a Phase API.  This shows the usefulness of Reversibility and Phase-Awareness for building large-scale Internet applications.

    [1] Ruma R. Paul, Peter Van Roy, and Vladimir Vlassov.  Reversible Phase Transitions in a Structured Overlay Network with Churn. NETYS 2016, Marrakech, Morocco, May 18-20, 2016.

    [2] Ruma R. Paul, Peter Van Roy, and Vladimir Vlassov.  Interaction Between Network Partitioning and Churn in a Self-Healing Structured Overlay Network. ICPADS 2015, Melbourne, Australia, Dec. 14-17, 2015.

  • Paul, Ruma
    et al.
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS.
    Paul, Ruma
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS.
    Van Roy, Peter
    Université catholique de Louvain, Belgium.
    Vlassov, Vladimir
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS.
    Reversible Phase Transitions in a Structured Overlay Network with Churn2016In: 4th International Conference on Networked Systems (NETYS), May 18-20, 2016, 2016Conference paper (Refereed)
    Abstract [en]

    Distributed applications break down when the underlying system has too many node or communication failures. In this paper, we propose a general approach to building distributed applications that lets them survive hostile conditions such as these failures. We extend an existing Structured Overlay Network (SON) that hosts a transactional replicated key/value store to be Reversible, i.e., it is able to regain its original functionality as the environment hostility recedes. For this paper we consider the environment hostility to be measured by the Churn parameter, i.e., the rate of node turnover (nodes failing and being replaced by new correct nodes). In order to describe the qualitative behavior of the SON at high churn, we introduce the concept of Phase of the SON. All nodes in a phase exhibit the same qualitative properties, which are different for the nodes in different phases. We demonstrate the existence of Phase Transitions (i.e., a significant fraction of nodes changes phase) as churn varies and show that our concept of phase is analogous to the macroscopic phase of physical systems. We empirically identify the Critical Points (i.e., when there exists more than one phase simultaneously in significant fractions of the system) observed in our experiments. We propose an API to allow the application layer to be informed about the current phase of a node.We analyze how the application layer can use this knowledge for self-adaptation, self-optimization and achieve reversibility in the application-level semantics.

  • Gustafsson-Ende, Linda
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Gustafsson-Ende, Linda
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    A visualization concept for production data and simulation results: Development and implementation of an adjustable visualization tool using SimAssist and d3.js at BMW AG2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The human’s visual system is one of the most powerful tools for discovering information and patterns in a given dataset. Increased possibilities for data collection and storage, together with today’s visualization software possibilities, help to facilitate visual analytics. Based on previous research within human perception, visualization techniques and a current situation analysis at BMW AG, a case study to develop and implement a visualization concept for production data and simulation results has been performed. The research question is formulated as how production and simulation data shall be presented in order to add value to the input data and material flow simulation results in the automotive industry. Production and simulation data are stored in databases that can be connected to SimAssist, a software tool developed for the assistance of simulation projects. In the 2view module of SimAssist, the plug-in SimVis offers visualization of selected data based on the front-end programming language JavaScript and the D3 library. D3 binds data to visual objects and manipulates their attributes. The case study has aimed to further develop the SimVis plug-in with regard to visual analytics. The visualization concept closes the observed gap between today’s visual analytic possibilities and the currently used software (often Excel and PowerPoint) at the material flow simulation group at BMW. Defining development and evaluation criteria, two concepts are generated and implemented using an agile method, continuously involving the future users. Two visualizations have been developed. The cluster visualization is a powerful tool that enables hierarchical clustering and visualization of data defined by the user via the user interface. The user interacts with the dataset, exploring relations by defining color ranges, hiding and showing selected nodes and calculating node values with different calculation methods (sum, median or average). Additionally, it includes a bar chart to facilitate a second overview of the dataset. The second concept is the multiline visualization, showing one scale with x-values and several lines with corresponding y-values. When the user moves the cursor over the visualization, the current x-data point, its corresponding y-values and the difference between the y-values are shown, in order to allow the user to interact with the dataset.The results show that the visualization concept is highly flexible, allowing different types and amount of data to be visualized and analyzed. By including the dataset in the SimAssist framework, a suitable visualization can easily be chosen and data can easily be displayed and visually analyzed in a visual analytics context. Interaction with the data via the mouse cursor helps into finding patterns and relations in and between the data and different datasets. The visualization concept saves several intermediate steps in comparison to today’s visualizations.

  • Public defence: 2016-10-14 11:00 K1, Stockholm
    Vardanyan, Yelena
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vardanyan, Yelena
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Optimal bidding of a hydropower producer insequential power markets with riskassessment: Stochastic programming approach2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Short-term hydropower planning and bidding under uncertainty is a complicated task. The problem became more challenging with the liberalized market environment within the last two decades. Apart from this new reform taking place in the electricity market, the electricity market participants including hydropower producers experienced the second change in the form of intermittent wind power integration into power systems. Thus, previous decision support tools are not capable of fulfilling market participants’ expectations in the new competitive and highly uncertain environment. Intermittent power sources, namely wind power, increase the imbalances in the power system, which in turn increases the need of the regulating power sources. Being a flexible energy source, hydropower can provide regulating power. For this purpose, new hydropower planning and bidding models must be developed, capable of addressing uncertainties and the dynamics existing within market places.

    In this dissertation, a set of new short-term hydropower planning and bidding models are developed for sequential electricity markets under price uncertainties. Developed stochastic coordinated hydropower planning and bidding tools can be classified into two classes, as models with exogenousand endogenous prices.

    In the first class, developed coordinated bidding tools address the price uncertainties using scenario trees, which are built based on the distribution function of the unknown variables. Thus, the proposed coordinated bidding and planning tools consider all possible future prices and market outcomes together with the likelihood of these market outcomes. To reflect the continuously clearing nature of intra-day and real-time markets rolling planning is applied. In addition, models apply risk measures as another way to hedge against uncertain prices.

    In the second class, hydropower stochastic strategic bidding models are developed using stochastic bi-level optimization methodology. Here market prices are calculated internally as dual variables of the load balance constraints in the lower level ED problems. To be able to solve the stochastic bilevel optimization problem, KKT optimality conditions are applied. By this transformation the problem is converted to a single-level stochastic program, which is simplified further using a corresponding discretization technique.

  • Thunell, Andreas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Thunell, Andreas
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Österblom, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    BIM: KOMMUNIKATION MELLAN PROJEKTERING OCH PRODUKTION: Hur BIM effektiviserar informationsflödet2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • EINARSSON, JOHANNA
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    EINARSSON, JOHANNA
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    SÖDERLUND, HELENA
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Prognostisering av produktionskapacitet - En studie på PET-Turbuhaler, AstraZeneca2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A company needs an accurate capacity plan to become successful. The capacity plan is an important tool for planning and anticipating production which is essential to be able to meet future demands. It is therefore of great importance to get an accurate forecasting of the production capacity, which is the main topic of this report.

    During the spring semester 2016, the authors of this report were contacted by the production unit PET-Turbuhaler at AstraZeneca in Södertälje. PET-Turbuhaler requested an accurate model for the long term, 12-24 months, forecasting of their production capacity. From this problem, a research question has been formulated into; Which is the best way for PET-Turbuhaler to work to reach an accurate long term, 12-24 months, production capacity prognosis?

    A pre-study, a literature study and an internal and an external benchmarking were conducted in order to answer the research question. The result from these were afterwards compiled and analyzed. The pre-study at PET-Turbuhaler gave an overview of the work with the current Microsoft Excel-model and its associated problems. The pre-study did also consist of the authors’ own analysis of PET-Turbuhalers capacity model.

    The literature study was made to investigate how theory advocates the work with capacity forecasting. It showed a difference between theoretical and real capacity. The real capacity is calculated by subtracting the plant’s scheduled and nonscheduled capacity losses (such as time losses for lunch, meetings, set-ups, machine breakdowns and defects from production) from the theoretical capacity. The theoretical capacity of the plant is the capacity when the plant runs 24 hours a day every day of the year.

    The analysis showed that the current model PET-Turbuhaler use today consist of more or less the same parameters as the literature suggests. The authors could therefore realize that the current model is not necessarily the main problem at this stage. The biggest problem is rather how the current model is being used by the employees. Parameters within the current model are not continuously updated with right data as PET-Turbuhaler thought. The consequence of this is that the long term forecasting is based on out-of-date data even though new and more accurate data is available.

    The research question can be answered based on the analysis. The most interesting result was the insight that the short term forecasting is not as accurate as PET-Turbuhaler believed. This gives, in order to achieve a good long term forecasting, that PET-Turbuhaler must first improve their short term forecasting by establishing a standardized way of working with the model. Only then can the long term forecasting be accurate.

    Through discussions regarding the result the authors were able to suggest improvements on how PET-Turbuhaler could work to reach an accurate long term forecast of their production capacity prognosis. The recommendations include continuous evaluation of collected data, regular meetings between production support and production line managers and the benefit of using a sensor, in the end of the production line, to registrate the output rate.

  • Larsson, David
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Larsson, David
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Inköpsuppföljning offentlig sektor - konsten att vara avtalstrogen2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • Magnusson, Sindri
    et al.
    KTH, School of Electrical Engineering (EES).
    Magnusson, Sindri
    KTH, School of Electrical Engineering (EES).
    Enyioha, Chinwendu
    Li, Na
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES).
    Practical Coding Schemes For Bandwidth Limited One-Way Communication Resource Allocation2016In: 55th IEEE Conference on Decision and Control (CDC), IEEE, 2016, Vol. 55Conference paper (Refereed)
    Abstract [en]

    This paper investigates resource allocation algorithms that use limited communication - where the supplier of a resource broadcasts a coordinating signal using one bit of information to users per iteration. Rather than relay anticipated consumption to the supplier, the users locally compute their allocation, while the supplier measures the total resource consumption. Since the users do not compare their local consumption against the supplier’s capacity at each iteration, they can easily overload the system and cause an outage (for example blackout in power networks). To address this challenge, this paper investigates pragmatic coding schemes, called PFcodes (Primal-Feasible codes), that not only allow the restriction of communication to a single bit of information, but also avoid system overload due to users’ heavy consumption. We derive a worst case lower bound on the number of bits needed to achieve any desired accuracy using PF-codes. In addition, we demonstrate how to construct time-invariant and time-varying PF-codes. We provide an upper bound on the number of bits needed to achieve any desired solution accuracy using time-invariant PF-codes. Remarkably, the difference between the upper and lower bound is only 2 bits. It is proved that the time-varying PF-codes asymptotically converge to the true primal/dual optimal solution. Simulations demonstrating accuracy of our theoretical analyses are presented.

  • Vardanyan, Yelena
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vardanyan, Yelena
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Hesamzadeh, Mohammad Reza
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Modeling Regime Switching in Day-ahead MarketPrices Using Markov Model2016Conference paper (Refereed)
  • Public defence: 2016-10-14 09:53 Kollegiesalen, Stockholm
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Extreme Implementations of Wide-Bandgap Semiconductors in Power Electronics2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wide-bandgap (WBG) semiconductor materials such as silicon carbide (SiC) and gallium-nitride (GaN) allow higher voltage ratings, lower on-state voltage drops, higher switching frequencies, and higher maximum temperatures. All these advantages make them an attractive choice when high-power density and high-efficiency converters are targeted. Two different gate-driver designs for SiC power devices are presented. First, a dual-function gate-driver for a power module populated with SiC junction field-effect transistors that finds a trade-off between fast switching speeds and a low oscillative performance has been presented and experimentally verified. Second, a gate-driver for SiC metal-oxide semiconductor field-effect transistors with a short-circuit protection scheme that is able to protect the converter against short-circuit conditions without compromising the switching performance during normal operation is presented and experimentally validated. The benefits and issues of using parallel-connection as the design strategy for high-efficiency and high-power converters have been presented. In order to evaluate parallel connection, a 312 kVA three-phase SiC inverter with an efficiency of 99.3 % has been designed, built, and experimentally verified. If parallel connection is chosen as design direction, an undesired trade-off between reliability and efficiency is introduced. A reliability analysis has been performed, which has shown that the gate-source voltage stress determines the reliability of the entire system. Decreasing the positive gate-source voltage could increase the reliability without significantly affecting the efficiency. If high-temperature applications are considered, relatively little attention has been paid to passive components for harsh environments. This thesis also addresses high-temperature operation. The high-temperature performance of two different designs of inductors have been tested up to 600_C. Finally, a GaN power field-effect transistor was characterized down to cryogenic temperatures. An 85 % reduction of the on-state resistance was measured at −195_C. Finally, an experimental evaluation of a 1 kW singlephase inverter at low temperatures was performed. A 33 % reduction in losses compared to room temperature was achieved at rated power.

  • HEINERUD, VICTOR
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    HEINERUD, VICTOR
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    SAHLSTEN, ANDRÉ
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Natural Refrigerants in Data Center Cooling with Thermosiphon Application2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ever since the computer was invented, there has been a need of data storage and the demand has strictly grown since. This has resulted in a huge amount of data centers and the trend has shown no signs of changing. The data centers are powered by electricity and in 2010 the electricity consumption for data centers stood for 1.3% of the world’s electricity usage. The most energy consuming part of a data center is the servers themselves, but the second largest energy consuming part is the cooling system which, in a normal data center, stands for two fifths of the energy usage. Besides the energy consumption, the cooling systems are in most cases a cooling machine using HCFC and HFC refrigerants. These refrigerants are all bad for the environment since HCFCs have high ODP and GWP values and HFCs have high GWP values.

    The purposes of this work is:

    A) Find a way to make the cooling systems more efficient. Previous work has shown that using free cooling from the ambient air is an effective method of reducing the yearly electricity demand. Further the systems use a two-phase thermosiphon to move heat from the servers to the ambient, which means that there is no need of pumping power.

    B) Find solutions using natural refrigerants that have no ODP and very low or zero GWP.

    C) Evaluated if there is a possibility to recover the waste heat from the data center to e.g. an office building.

    This work contains two systems being mathematically modeled with the software Engineering Equation Solver: a direct R744 system and an indirect system running with R290 and R744. Both systems are using a thermosiphon application, connected to a condenser, to use free cooling up to a certain set point temperature and the rest is covered with a vapor compression cycle. These systems are then matched to temperature profiles for five cities, Stockholm, Paris, Phoenix, Tokyo and Madrid, to see how many hours of the year are covered by free cooling. The systems are then evaluated considering both energy consumption and cost. To be able to compare these systems to a present cooling system, a reference system is modeled which uses R22 as refrigerant, that is the most commonly used refrigerant in the world today for the data center cooling application.

    The results show that a direct R744 system or an indirect system with R290/R744 with a thermosiphon application have both energy and economical savings compared to the reference system. The energy savings are up to 88% and the total annual cost savings are up to 69%. The Power Usage Effectiveness is reduced with up to 6% and up to 8% if only cooling is considered. These savings are for an optimized condenser with a 2000 m2 fin area and 6 fans with a set point temperature of 22°C.

    The indirect R290/R744 system is the best in all cities considering energy efficiency. Both systems are also well suited for use with heat recovery. The Seasonal Performance Factor for the heat recovery is between 8.3 and 15.2, which is a consequence of the high evaporation temperature and low supply temperature to the heating system.

  • Franzén, Linda
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Franzén, Linda
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Fredheim, Jessica
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Potential Sustainability Improvements by Using Real-Time Measuring Temperature Sensors in Offices: A Case Study at Vasakronan’s Head Office Evaluating Sensor Solutions and Their Applicability.2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is written on the subject of smart cities, where real-time temperature measuringsensors were tested at Vasakronan’s head office. The purpose of doing so was to evaluate theavailable sensor solutions for real-time measurements as well as analyze the sustainabilitybenefits of doing so. Three sensors were tested: Yanzi Climate, Texas Instruments SensorTag,and Smart Citizen Board. The measurements from the sensors were compared within the sensorsolution as well as between each other and the traditional measuring equipment Testo 480 andTinytags. A multi-criteria analysis was conducted to compare the qualities of the sensors, whichshowed that Yanzi was the best of these. Mainly this was due to the quality of measurementsand conformity within the sensor solution. The performance of the other sensor solutions weresimilar, although they had different strengths and weaknesses. Finally, the temperaturemeasurements from Yanzi was used to make a temperature map over the office. If implementedin real-time, this would serve as an indicator for the superintendents of the building whenmanaging the HVAC system, which could improve energy efficiency and decrease costs.Additionally, employees could use the temperature map for individual choice of the indoortemperature that suits them. This will result in improving social sustainability at the office, aswell as economic sustainability due to increased productivity of the employees.

  • Public defence: 2016-10-13 15:05 T2, Huddinge
    Widman, Erik
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Widman, Erik
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Ultrasonic Methods for Quantitative Carotid Plaque Characterization2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cardiovascular diseases are the leading causes of death worldwide and improved diagnostic methods are needed for early intervention and to select the most suitable treatment for patients. Currently, carotid artery plaque vulnerability is typically determined by visually assessing ultrasound B-mode images, which is influenced by user-subjectivity. Since plaque vulnerability is correlated to the mechanical properties of the plaque, quantitative techniques are needed to estimate plaque stiffness as a surrogate for plaque vulnerability, which would reduce subjectivity during plaque assessment. The work in this thesis focused on three noninvasive ultrasound-based techniques to quantitatively assess plaque vulnerability and measure arterial stiffness. In Study I, a speckle tracking algorithm was validated in vitro to assess strain in common carotid artery (CCA) phantom plaques and thereafter applied in vivo to carotid atherosclerotic plaques where the strain results were compared to visual assessments by experienced physicians. In Study II, hard and soft CCA phantom plaques were characterized with shear wave elastography (SWE) by using phase and group velocity analysis while being hydrostatically pressurized followed by validating the results with mechanical tensile testing. In Study III, feasibility of assessing the stiffness of simulated plaques and the arterial wall with SWE was demonstrated in an ex vivo setup in small porcine aortas used as a human CCA model. In Study IV, SWE and pulse wave imaging (PWI) were compared when characterizing homogeneous CCA soft phantom plaques. The techniques developed in this thesis have demonstrated potential to characterize carotid artery plaques. The results show that the techniques have the ability to noninvasively evaluate the mechanical properties of carotid artery plaques, provide additional data when visually assessing B-mode images, and potentially provide improved diagnoses for patients suffering from cerebrovascular diseases.

  • Nyawo, Talent
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Nyawo, Talent
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Design of a rotary valve for pressurised steam2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master thesis is a project commissioned by the Swedish company Ranotor AB. The objective of this thesis is to develop a conceptual solution for a rotary valve mechanism that has to work efficiently in a high-temperature and high-pressure environment. The valve is to operate at high rotational speeds which calls for very short opening time.Modern engineering tools namely Solidworks, Ansys and Matlab, were employed for modelling and analysis of the conceptual solution.The best design solution was selected from three developed concepts, and the selected concept was further developed and optimized. Major material candidates and gas-tight sealing solution were identified and evaluated and the optimal material and seal design was chosen. Optimization of the individual components as well as the whole assembly was performed based on stress, thermal and dynamic analysis. The given design specifications and functions were fulfilled and the results were satisfactory. The obtained results provide a theoretical foundation for the development and application of a rotary valve in high-temperature and high-pressure environment.

  • Public defence: 2016-10-14 13:00 FD5, STOCKHOLM
    Zhou, Tunhe
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Zhou, Tunhe
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Laboratory X-Ray Phase-Contrast Imaging: Methods and Comparisons2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    X-ray phase-contrast imaging has seen rapid development in recent decades due to its superior performance in imaging low-absorption objects, compared to traditional attenuation x-ray imaging. Having higher demand on coherence, x-ray phase-contrast imaging is performed mostly at synchrotrons. With the development of different imaging techniques, and the development of laboratory sources and x-ray optics, x-ray phase-contrast imaging can now be implemented on laboratory systems, which is promising and practical for broader range of applications.

    The subject of this thesis is the implementation, development and comparison of different laboratory phase-contrast methods using a liquid-metal-jet source. The three x-ray phase-contrast imaging methods included in this thesis are the propagation-, grating-, and speckle-based techniques. The grating-based method has been implemented on a laboratory system with a liquid-metal-jet source, which yields several times higher brightness than a standard solid-anode microfocus source. This allows shorter exposure time or a higher signal-to-noise ratio. The performance of the grating-based method has been experimentally and numerically compared with the propagation-based method, and the dose required to observe an object as a function of the object’s diameter has been investigated with simulations. The result indicates a lower dose requirement for the propagation-based method in this system but a potential advantage for the grating-based method to detect relatively large samples using a monochromatic beam.

    The speckle-based method, both the speckle-tracking and speckle-scanning techniques, has been implemented on a laboratory system for the first time, showing its adaptability to radiation of low temporal coherence. Tomography has been performed and shows the potential applications of this method on quantitative analysis on both absorption and phase information of materials. As a basis for further optimization and comparisons to other methods, the noise properties of the differential phase contrast of the speckle-based method have been studied and an analytical expression for the noise variance introduced, showing a similarity to the grating-based method.

  • Alvarsson, Fredrik
    KTH, School of Engineering Sciences (SCI), Physics.
    Alvarsson, Fredrik
    KTH, School of Engineering Sciences (SCI), Physics.
    An interactive computer terminal about particle physics and the Atlas Experiment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Romell, Jenny
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Romell, Jenny
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Comparison of Grating- and Speckle-Based X-Ray Phase-Contrast Imaging2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Östlund, Rasmus
    KTH, School of Engineering Sciences (SCI), Physics.
    Östlund, Rasmus
    KTH, School of Engineering Sciences (SCI), Physics.
    PoGO+ Detector Cell Characterisation and Optimisation of Waveform Selection Parameters2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Oudenot, Hélèna
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Oudenot, Hélèna
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Indirect Estimation of Persistent Inward Currents in Patients with Amyotrophic Lateral Sclerosis2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Li, Yichuan
    KTH, School of Engineering Sciences (SCI), Physics.
    Li, Yichuan
    KTH, School of Engineering Sciences (SCI), Physics.
    CFD Pre-test Analysis of SIMECO-2 Experiment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Gojan, Agnieszka
    KTH, School of Engineering Sciences (SCI), Physics.
    Gojan, Agnieszka
    KTH, School of Engineering Sciences (SCI), Physics.
    Advanced Modeling of Pellet-Cladding Interaction2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis