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  • Scott, Mikael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Interactions of Divalent Cations with the Carboxylate Moiety: A Vibrational Sum Frequency Study2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The interactions between the divalent salts CaCl2, MnCl2 and NiCl2 with the carboxylicacid groups in an arachidic acid Langmuir monolayer are studied using vibrational sumfrequency spectroscopy (VSFS). At low salt concentrations the charging of the monolayer is shown to behave in accordance with classical theories of the electrical doublelayer. However, deviations from classical theories are readily apparent at concentrations starting from 1 μM and shown to differ depending on the nature of the cation, indicating an ion specific effect. From the analysis of the carboxylate symmetric vibration at least two different types of ion pair interactions between the divalent cations and the carboxylicacid moiety are detected: a solvent-separated and two (or more) possible contact ion-pairs and/or complexes. By using different VSFS polarization schemes the molecular orientation of the vibration is elucidated and further insight into the state of the carboxylic acidis gained. The ordering of water molecules in the diffuse layer as a result of the surfacepotential of the charged monolayer is also probed and found, at low ionic strengths, to bein agreement with the behaviour predicted by the Gouy-Chapman model. At high concentrations the hydration within the Stern layer can be detected and found to differ with the nature of the electrolyte. Additionally, the importance of the purity grade of the salts used for correctly interpreting the results is shown theoretically and verified experimentally,where trivalent ions affect the surface at concentrations several orders of magnitude below those from mono and divalent ions. Finally, diffusion is shown to play a major rolein the kinetics of deprotonation of the monolayer at submicromolar concentrations, while higher valency cations are also shown to deprotonate the surface at a quicker rate through electroflux.

  • Othman, Nicole
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    Zakir, Adrian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    Utveckling av sparapplikation: En fallstudie om hur man utvecklar en applikation som påverkar människans kognitiva beteende2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To establish an own private savings, for both long-term as well as short-term goals, is a wish that most people have. Looking at the current housing market, there can be some difficulties for young adults, especially in the Stockholm county, to become an owner of a household. This due to the fact that an investment of this kind, often requires the individual to save up for a down payment. 

    This study has been conducted in order to obtain an answer on how to, in an application, affect human cognition and motivate individuals to increase their private savings. As a given assignment from the IT-consulting company Etimo AB, a prototype of a savings-application has been constructed during this study.

    The solution is a result based on various data collection methods as well as a software development process. The results of the study, in which usability tests and surveys where the most important ones, showed that gamification is a concept which can be used in an application in order to affect human cognition. The results showed more specifically that elements from game design, such as trophies and progress bars, have a positive effect on the users motivation.

  • Verlhac, Clément
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Temperature dependence study of materials and nanostructures for infrared emission2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Bälter, Olle
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Media Technology and Interaction Design, MID.
    Riese, Emma
    KTH, School of Electrical Engineering and Computer Science (EECS), Theoretical Computer Science, TCS.
    Enoksson, Fredrik
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Hedin, Björn
    KTH, School of Electrical Engineering and Computer Science (EECS), Media Technology and Interaction Design, MID.
    Baltatzis, Alexander
    KTH, School of Electrical Engineering and Computer Science (EECS), Media Technology and Interaction Design, MID.
    Josefsson, Pernilla
    KTH, School of Electrical Engineering and Computer Science (EECS), Media Technology and Interaction Design, MID.
    The Challenge of Identifying the Importance of Drivers and Barriers for Implementation of Technology Enhanced Learning2018In: The 11th Pan-Hellenic and International Conference: ICT in Education, 2018, p. 283-290Conference paper (Refereed)
    Abstract [en]

    The potential of technology enhanced learning (TEL) can have both pedagogical and administrative benefits. In a previous study, we investigated the drivers and barriers for TEL in higher education using Force Field Analysis (FFA). In this follow-up study, we collected new data through a questionnaire to a group of pedagogical developers and at a presentation at a university internal conference for teachers. A Kruskal Wallis test was carried out to test if the groups filling out questionnaire deviated from each other in their ranking. A comparison was also done to the scores in the previous study. As a result of this triangulation, deviations were found between ratings for seven of the 20 identified forces. While the assessments of strengths in FFA is debated, we argue that each group’s view is an important component to understand the situation, and triangulation of data is helpful in understanding the different views.

  • Peerlings, Luck
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Measured scattering and absorption coefficients of an area expansion with flow.2018Data set
  • Public defence: 2019-03-15 13:30 Ka-Sal C (Sal Sven-Olof Öhrvik), Stockholm
    Peiro Sajjad, Hooman
    KTH, School of Electrical Engineering and Computer Science (EECS), Software and Computer systems, SCS.
    Methods and Algorithms for Data-Intensive Computing: Streams, Graphs, and Geo-Distribution2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Struggling with the volume and velocity of Big Data has attracted lots of interest towards stream processing paradigm, a paradigm in the area of data-intensive computing that provides methods and solutions to process data in motion. Today's Big Data includes geo-distributed data sources.In addition, a major part of today's Big Data requires exploring complex and evolving relationships among data, which complicates any reasoning on the data. This thesis aims at challenges raised by geo-distributed streaming data, and the data with complex and evolving relationships.

    Many organizations provide global scale applications and services that are hosted on servers and data centers that are located in different parts of the world. Therefore, the data that needs to be processed are generated in different geographical locations. This thesis advocates for distributed stream processing in geo-distributed settings to improve the performance including better response time and lower network cost compared to centralized solutions. In this thesis, we conduct an experimental study of Apache Storm, a widely used open-source stream processing system, on a geo-distributed infrastructure made of near-the-edge resources. The resources that host the system's components are connected by heterogeneous network links. Our study exposes a set of issues and bottlenecks of deploying a stream processing system on the geo-distributed infrastructure. Inspired by the results, we propose a novel method for grouping of geo-distributed resources into computing clusters, called micro data centers, in order to mitigate the effect of network heterogeneity for distributed stream processing applications. Next, we focus on the windowed aggregation of geo-distributed data streams, which has been widely used in stream analytics. We propose to reduce the bandwidth cost by coordinating windowed aggregations among near-the-edge data centers. We leverage intra-region links and design a novel low-overhead coordination algorithm that optimizes communication cost for data aggregation. Then, we propose a system, called SpanEdge, that provides an expressive programming model to unify programming stream processing applications on a geo-distributed infrastructure and provides a run-time system to manage (schedule and execute) stream processing applications across data centers. Our results show that SpanEdge can optimally deploy stream processing applications in a geo-distributed infrastructure, which significantly reduces the bandwidth consumption and response latency.

    With respect to data with complex and evolving relationships, this thesis aims at effective and efficient processing of inter-connected data. There exist several domains such as social network analysis, machine learning, and web search in which data streams are modeled as linked entities of nodes and edges, namely a graph. Because of the inter-connection among the entities in graph data, processing of graph data is challenging. The inter-connection among the graph entities makes it difficult to distribute the graph among multiple machines to process the graph at scale. Furthermore, in a streaming setting, the graph structure and the graph elements can continuously change as the graph elements are streamed. Such a dynamic graph requires incremental computing methods that can avoid redundant computations on the whole graph. This thesis proposes incremental computing methods of streaming graph processing that can boost the processing time while still obtaining high quality results. In this thesis, we introduce HoVerCut, an efficient framework for boosting streaming graph partitioning algorithms. HoVerCut is Horizontally and Vertically scalable. Our evaluations show that HoVerCut speeds up the partitioning process significantly without degrading the quality of partitioning. Finally, we study unsupervised representation learning in dynamic graphs. Graph representation learning seeks to learn low dimensional vector representations for the graph elements, i.e. edges and vertices, and the whole graph.We propose novel and computationally efficient incremental algorithms. The computation complexity of our algorithms depends on the extent and rate of changes in a graph and on the graph density. The evaluation results show that our proposed algorithms can achieve competitive results to the state-of-the-art static methods while being computationally efficient.

  • Zulu, Andrew Wisdom
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Thick Composite Properties and Testing Methods2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In most application to date reinforced carbon fiber composites have been used in relatively smaller thickness, less than 10mm thick and essentially for carrying in-plane loads. As a result, design and testing procedures were developed which reflected the need to understand the in-plane response of the material. recently, engineers and designers have begun to use reinforced carbon fiber composites in thicker sections, where an understanding of the through-thickness response is of para-mount importance in designing reliable structures, particularly where the through-thickness strength has a controlling influence on the overall structural strength of the component. In this thesis tests will be done on carbon fiber non-crimp fabric (NCF) which will be loaded in compression and shear and elastic moduli and strength will be evaluated. In characterizing the through-thickness mechanical properties of a composite, the objective is to produce a state of stress in the test specimen which is uniform and will repeatedly measure the true properties with accuracy. In this study, specimens were machined from two blocks of thick (~20 mm) laminates of glass/epoxy and NCF carbon fiber infused with vinylester and tested in compression, and shear.

  • Westbeld, Julius
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Investigation of support structures of a polymer powder bed fusion process by use of Design of Experiment (DoE)2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, support structures of a polymer powder based process called XXXXXXXX™ are examined. These structures are crucial for most additive manufacturing processes. The effects of several factors on five industrially important characteristics of support structures are examined by use of the Design of Experiment (DoE) method. It describes the planning as well as the analysis of the experiments. The experiments are planned in a fractional factorial 211-5 design with 64 specimens, resulting in a resolution of IV. The analysis of the data is done by use of the ANOVA method, with which the significance of effects and interaction effects are checked.

  • Rydelius, Frida
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Implementation of Thermal Aspects in Topology Optimization in a Multi-Disciplinary framework for a Turbine Rear Structure2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the possibilities of implementing thermal aspects in Topology Optimization (TO) of hot engine structures. Topology Optimization is an effective tool for conceptual design in numerous field of applications. At GKN, this optimization technique has previously only been successfully implemented for structures affected by mechanical loads. The aim with this study and the ongoing research at GKN, is to improve the in-house developed multi-disciplinary optimization procedure called Engineering WorkBench (EWB). By expanding the applicability of a more comprehensive TO which includes the thermal expansion. However, since there is no straight forward solution provided by the FE software’s, a better understanding of TO in general and for thermally loaded structures in particular, is needed before deciding on an application strategy.Two approaches for the thermal implementation in TO of the Turbine Rear Structure (TRS) have been studies and evaluated. The first is a stress constrained optimization procedure, based on requirements for the number of thermal load cycles, calculated in CUMFAT, an in-house developed program for life prediction. The second approach is a case trial study of the coupled thermal-mechanical structural optimization. The trials are performed systematically to illustrate what type of geometrical variations one can expect in the TO outcome when varying different factors in the optimization set up, such as the load type magnitude and optimization formulation. The evaluation of these to different approaches will increase the understanding of the challenges involved when performing TO of this type of structure.The complexity of this implementation is clearly demonstrated by the variation in optimization outcome. The results shows the importance of having substantial knowledge about the model, load cases and the optimization purpose before defining the optimization problem. Finally, suggestions for the continuation and implementation of thermal TO in the EWB, are presented.

  • Jeannin, Baptiste
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Transformation of a metallic frame into a composite frame2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This document is a report of my thesis which deals with the transformation of a metallic frame into a composite frame. A composite frame would require less assembly time since it is composed of less components. The maintenance plan, required for metallic structures, would not be required anymore. Finally, the weight of the structure could be reduced.The resolution of this problematic is done in the following way. Once the pre-design of the frame settled, the finite element model is modified accordingly. The finite element outputs give the load per finite element and enable a sizing of the whole structure per section and per element. The design of the frame is then modified according to the results, the finite element model modified again and the sizing conducted another time until the design is in accordance with the design and sizing requirements.The results of this whole procedure give a structure that can withstand the critical loads but an increase in the weight by 1,65kg. When analyzing the results, the design of the frame, taken from a metallic frame and thus higher than a usual composite frame, appears to be unappropriated. Furthermore, the sizing of the skin for buckling failure is already at its limit. A modification in the shape of the frame, and especially the height, would be the most efficient way to adapt the design.Though possible, this modification would require a laborious and important change of the finite element model, which is not the aim of the thesis but could constitute another interesting topic to work on.

  • Arvidsson, Daniel
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Additive weld manufacturing and material properties effect on structural margins2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    the FE analyses. Traditionally all parts are modeled with isotropic base material. Analyses are made on a part of the nozzle which includes both a butt weld and metal deposition and which is an interface to another part causing loads that has to be sustained by the weld and the MD. As a small part of this thesis was also a fatigue study made to a spot weld test specimen.

    In order to strengthen the nozzle to prevent structural damage, an outer layer is added to the already existing metal cone by material deposition, MD, or additive manufacturing. During the manufacturing process the material will indicate some degree of anisotropic properties.

    The key purpose of this thesis was to analyze how this anisotropic behaviour might affect the structural stiffener connected to this anisotropic material when exposed to a load at the end of the stiffener. Further analysis due to fatigue was also done to parts of the structure. The procedure was done by building a model and setting up the different anisotropic properties with help of a finite element program, Ansys. The material properties regarding the anisotropy of the material was changed and compared in order to see how it affected stresses and strains in the anisotropic material and it‘s surrounding materials. Further analysis was made to the properties of the weld such as the yield limit.

    The result would indicate that for loadings that did not generate plastic deformations, hence elastic deformations, there were no significant difference forthe different trial values of the yield ratios. However, the differences became parent when studying large plastic deformations. Variation of the Young’s modulus would show some differences in the monitored properties for both elastic and plastic deformations. Studies of degrading the welds yield limit would show no diffrences when elastic deformations were present, but would have a big impact when large plastic deformations were present. The J-values variations for the spotweld would indicate huge differences depending on the yield limits for the spotweld and base material.

  • Peiro Sajjad, Hooman
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Software and Computer systems, SCS.
    Docherty, Andrew
    Data61, CSIRO.
    Tyshetskiy, Yuriy
    Data61, CSIRO.
    Efficient Representation Learning Using RandomWalks for Dynamic GraphsManuscript (preprint) (Other academic)
    Abstract [en]

    An important part of many machine learning workflows on graphs is vertex representation learning, i.e., learning a low-dimensional vector representation for each vertex in the graph. Recently, several powerful techniques for unsupervised representation learning have been demonstrated to give the state-of-the-art performance in downstream tasks such as vertex classification and edge prediction. These techniques rely on random walks performed on the graph in order to capture its structural properties. These structural properties are then encoded in the vector representation space. 

    However, most contemporary representation learning methods only apply to static graphs while real-world graphs are often dynamic and change over time. Static representation learning methods are not able to update the vector representations when the graph changes; therefore, they must re-generate the vector representations on an updated static snapshot of the graph regardless of the extent of the change in the graph. In this work, we propose computationally efficient algorithms for vertex representation learning that extend random walk based methods to dynamic graphs. The computation complexity of our algorithms depends upon the extent and rate of changes (the number of edges changed per update) and on the density of the graph. We empirically evaluate our algorithms on real world datasets for downstream machine learning tasks of multi-class and multi-label vertex classification. The results show that our algorithms can achieve competitive results to the state-of-the-art methods while being computationally efficient.

  • Emilia, Eriksson
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Planning for sea level rise in Sweden: A study regarding how the parliamentary parties relate to climate change adaptation of sea level rise2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The consequences due to sea level rise are many, and will affect the environment and societies all around the world. There is uncertainty about how much and how quickly the sea will rise. Despite the uncertainties, society must be adapted to a changing climate. The climate change adaptation work is relatively new in Sweden, and there are still uncertainties about how this work should be carried out, and by whom.

    This thesis examines to what degree the Swedish parliament parties’ view on how to plan and adapt to sea level rise differ. The study is based on interviews with representatives from a majority of the political parties in the Swedish parliament.

    The results show that the interviewed representatives all agree that climate change and sea level rise are important issues to work with. The result also shows that the different parties have managed to agree on what they want to achieve, but not how or when it is best to implement adaptation measures towards sea level rise and other climate change-related effects.

  • Bern, Caroline
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Bedömning av kompetens i tekniska karriärspår: En fallstudie om hur föreställningar om kompetens, kompetensbedömning och karriär påverkar organisationers möjlighet att skapa inkludering och mångfald2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Having a diverse workforce has become an important issue in today’s organizations in order to capture a wide range of competence, skills and abilities. Today many companies encourage work with diversity and inclusion since they argue that it increases creativity and, in extent, company profit. However, many companies struggle to manage such work in a successful way. A method of creating the prerequisites for diversity and inclusion is to study the perception of competence and assessment processes. Assessment of competence is, for example, the basis for decision making in career advancement. The assessment requires one to decide on what competence is and in turn who is competent. The complexity of the concept of competence and norms being a part of the assessment process complicates such decisions. As an attempt to ensure that competence is assessed objectively, many companies apply different formalized procedures for inclusion and diversity work. This study aims to provide a deeper understanding of how career, assessment of competence and formalized procedures interact.

    A case study has been carried out in an engineering industry, which is referred to in the report as Organization A. The purpose of the study was to examine how formalized technical careers affect organizations' ability to create inclusion and diversity, based on perceptions of competence, competence assessment and career. To fulfil the purpose, the following two questions were stated.

    1. How are technical careers structured?
    2. What conditions do technical careers create for equal assessment of competence?

    In the study, a technical career path has been investigated within Organization A. The thesis is part of a MSc in Engineering and Education at KTH. The engineering part of the work is reflected in the technical point of view of the work where an organization with technology-intensive activities has been placed in focus. The educational part of my degree is applied by relating the organization's technical career paths to similar organizations in education, discussing similarities and differences in assessment processes. In order to answer the research questions, interviews with employees and focus groups with managers within Organization A have been conducted. The study shows how technical careers are organized based on formal and informal structures related to assessment of competence and norms affecting assessment processes. The observed technical career path within Organization A is based on an informal pyramid structure that allows for subjective perceptions of the purpose and goals of the career. This enables a view of employees' different capabilities to reach higher levels and is therefore problematized from a diversity and inclusion perspective.

    The assessment criteria of the career path provide room for interpretation and there is no education or support for managers how the criteria should be interpreted and applied. It is a result of a lack of management required to ensure that the career process is used the intended way. The shortcoming contributes to the fact that norms and prejudices can continue to influence the assessment process. The organization's implemented diversity and inclusion work provide some management but is done without caution. Processes of change requires follow-up and evaluation which is lacking. The organization can learn from what in learning research is addressed as formative assessment. The study shows a shortcoming in all three key parts included in formative assessment. Based on stated conclusions, recommendations are given to Organization A to question the purpose of the pyramid structure and to apply clearer management in terms of education and forums for collaboration. Additionally, recommendations are given for how the organization can apply formative assessment in career assessment processes.

  • Mikaelsson, Tobias
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Gymnasiematematik under sommaren: Elevers uppfattningar om sommarskola2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Summer schools in Sweden are used to achieve a pass grade for those students who have not achieved a pass grade during the regular school. There are statistics on how many people go to summer school, and how many people achieve pass grades, but there is very little research on what kind of teaching and learning takes place at summer schools. The purpose of this thesis is to gain better knowledge of mathematics teaching at summer schools, what learning is made possible there and students' perceptions of their learning. A qualitative study of mathematics teaching at a summer school in Sweden has been performed, where the data consists of interviews, observations and a written evaluation. Thematic analysis has been used to find patterns within the study data. The analysis results indicate that the students' work effort is much better at summer school compared to the regular school and is also perceived by the students themselves as much better because of higher motivation and a better study environment. This higher motivation can be related to the students having a short and clear objective.

  • Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Antenna-to-Antenna Isolation Measurements1999Report (Other academic)
    Abstract [en]

    In this document we show results from measurements of the antenna-to-antenna isolation between different types of base station antenna configurations. The measurements are conducted on antennas for the GSM1800 band. However, since this band is relatively close to the IMT-2000 band it is reasonable to assume similar results for antennas to be used in this band.

    In this report we present measurement results from antennas with both vertical and slanted dual polarisation, and different horizontal beamwidths. The different antennas are shown in Table 1. The isolation is measured with the antennas positioned for some different configurations.

  • Public defence: 2019-03-13 22:41 F3, Stockholm
    Wu, Yiming
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    Quality Assurance of Time Critical Data Using Adaptive Data Delivery Mechanisms in Smart Grids2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Smart grids are proposed to integrate renewable energy and to improve the efficiency of power system operation. The challenges of integrating renewable energy are the inherent fluctuations of generation which are difficult to predict which may lead to challenges to the safe operation of power systems. Improving the efficiency of power systems means they should be operated closer to their limits. To solve these challenges, advanced protection and control applications, have been proposed that increase the accuracy of reactions and reduce the response time to events and faults. However, not all the data required for these applications can be delivered by the conventional Supervisory Control And Data Acquisition (SCADA) systems. As an example, synchrophasor data are intended to be delivered via a Wide Area Monitoring and Control (WAMC) system, which can be seen as a parallel data delivery infrastructure to SCADA. As deployment of intelligent substation secondary devices such as Intelligent Electronic Devices (IEDs), Merging Units (MUs), and Phasor Measurement Units (PMUs), data volume and data resolution in the power systems is increasing. To flexibly share data in the power system, different data delivery architectures have been proposed. Flexible data sharing brings benefits of information resiliency from different data sources. But it also raises the requirements on cyber-security for protection of the smart grid applications. Such needs are in turn being gradually addressed by new cyber-security mechanisms.

    In this thesis, the main quality attributes for time critical smart grid applications being; data accuracy, information resiliency, communication performance, and cyber-security and their interrelation are studied. Most previous research has been focused on assurance on one of these quality attributes, while in practical implementation the attributes are clearly related and interdependent. There is consequently a lack of study of the interactions between these quality attributes.

    This thesis focuses on the interactions of three pairs of these four time critical data quality attributes. The hypothesis of the interaction of each pair has been formulated as research question which is answered in different sections of the thesis. The results of this thesis show that information resiliency can increase the data accuracy and enhance the communication performance assurance to the smart grid application. This is in the thesis shown by two of the contributions presented in this thesis, being the implementation and validation of an adaptive data source selection mechanism to realize at substation level and wide area system level separately. In addition, since cyber-security mechanisms can affect the communication performance, specifically latency, and a trade off between security and performance may be needed. A third contribution in the thesis is a framework incorporating these two time critical quality attributes consisting of  an adaptive cyber-security scheme which contributes to the incorporation of performance requirements.

  • Zalejska-Jonsson, Agnieszka
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    Perceived Acoustic Quality and Effect on Occupants’ Satisfaction in Green and Conventional Residential Buildings2019In: Buildings, ISSN 2075-5309, E-ISSN 2075-5309, Vol. 9, no 1, article id 24Article in journal (Refereed)
    Abstract [en]

    The study presented in this paper focuses on the subjective opinions of occupants of multistory residential buildings by examining the relationship between occupants’ satisfaction and indoor environment quality, and analysing the effect the problems experienced with noise level may have on general satisfaction and the perceived acoustic quality. The analysis is based on data collected through surveys addressed to adults living in green and conventional buildings. The results show that occupants are very satisfied with their apartments, and subjectively rated acoustic quality received very high scores. The responses indicate that noise from neighbours has been experienced relatively seldom by occupants; however, the analysis shows that it is the factor that has the strongest effect on satisfaction with acoustic quality. We have found that the environmental profile of a building has a significant effect on general satisfaction expressed by occupants; however, this effect has not been confirmed for acoustic quality.

  • von Heland, Jacob
    et al.
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    Ernstson, Henrik
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    One Table Two Elephants: A cinematic ethnography about race, nature and ways of knowing the postcolonial city2018Other (Other academic)
    Abstract [en]

    "One Table Two Elephants" is a cinematic ethnography about race, nature and ways of knowing the postcolonial city. 

    SYNOPSIS – This is a film about bushmen bboys, a flower kingdom and the ghost of a princess. Entering the city through its plants and wetlands, the many-layered, painful and liberating history of the city emerges as we see how biologists, hip hoppers, and wetland activists each searches for ways to craft symbols of unity and cohesion. But this is a fraught and difficult task. Perhaps not even desirable. Plants, aliens, memories and ghosts keep troubling efforts of weaving stories about this place called Cape Town.

    THE PROCESS – Situated and grounded in lived experiences across a range of groups, this film follows different ways of knowing and tries to be a vehicle toward difficult yet urgently needed conversations about how race, nature and the city are intertwined in our postcolonial world where history is ever present in subtle and direct ways. This cinematic ethnography brings texture to understand a city like Cape Town, while providing possibilities to translate what is happening “there” to conversations about any city and its surroundings.

    CONTEXT – One Table Two Elephants is created in a context of long-term urban research in Cape Town with an environmental and social science orientation. It is part of the projects Ways of Knowing Urban Ecologies and Towards a Visual Environmental Humanities at the KTH Environmental Humanities Lab that produce explorative and artistic forms academic knowledge production beyond writing and text.

    CREATED BY – Jacob von Heland and Henrik Ernstson. Cinematography: Johan von Reybekiel. Sound: Jonathan Chiles. Editing: Jacob von Heland. Assistant Editing: Henrik Ernstson. Sound Design and Mix: Jakob Oldenburg. Production Coordination: Jessica Rattle and Nceba Mangesi. Color grade: Johan von Reybekiel. Original Music: Louise Becker. Graphic Design: Erik Hartin.

    PRODUCED BY – Telltales Film, in collaboration with The Situated Ecologies Platform, African Centre for Cities University of Cape Town and the KTH Environmental Humanities Lab. Support by the Swedish Research Council Formas and Stiftelsen Marcus och Amalia Wallenbergs Minnesfond.

  • Vallien, Ante
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Material characterization of multi-layered Zn-alloy coatings on fasteners: Effects on corrosion resistance, electrical conductivity and friction2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Electroplated zinc-alloy coatings have been used on fasteners in the automotive industry for many years. The coating often consists of three layers: a zinc-alloy layer, a passivation layer and a sealer or top-coat. The coating layers affect the functional properties of the fastener (mainly the corrosion resistance, friction coefficient and electrical conductivity), and the aim of this thesis has been to increase the understanding of how these functional properties are affected by the properties of the coating.

    The corrosion resistance, friction coefficient and electrical conductivity of several different fasteners have been tested. Variations in these properties are connected with morphological and chemical properties of the electro-deposited zinc-alloy coating, passivation layer and sealer/top-coat of the fasteners. Measurement methods include scanning electron microscope and energy dispersive x-ray spectroscopy (SEM-EDX), light optical microscope (LOM), x-ray fluorescence (XRF), glow discharge optical emission spectroscopy (GD-OES), broad ion beam (BIB) and Fourier transform infrared spectroscopy (FTIR).

    From the results it can be concluded that the surface structure of zinc-nickel layers differs significantly from supplier to supplier. Screws with a thicker and rougher zinc-nickel surface structure displays higher friction values, but lower electrical resistance values. Optimisation of both of these properties is thus challenging. The distribution and surface structure of the outmost top-coat layer also differs between suppliers, but no connection between this and the functional properties of the screw has been found. The corners of the screw heads are often lacking a proper zinc-alloy coating, and this is also where corrosion is initiated. In general, the zinc-nickel alloy coating systems are performing better and display less corrosion spreading effects than the zinc-iron or pure zinc systems in terms of corrosion.

  • Hjelmtorp, Kristofer
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Resistance Spot Welding of ALSI-coated UHSS: An experimental study2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The automotive industry of today faces ever harder requirements from regulatory bodies to increase the fuel efficiency, reduce the carbon footprint and increase the safety of their vehicles. The problem is being tackled in different ways; one of them being the use of innovative materials to reduce the overall weight while improving the crash safety of the vehicle. One such material is 22MnB5, an ultra-high strength (UHS) boron-alloyed steel, capable of reaching tensile strength of 1900 MPa.

    The weldability is a vital factor for applying boron steel in an efficient way into a vehicle construction. Resistance spot welding (RSW) is, among the different welding methods, the primary joining methods used within the automotive industry. The main challenges with RSW of UHS boron steel is the narrow welding window and increased risk of expulsion compared to conventional automotive steel.

    The aim of this thesis was evaluating how the weldability of three-sheet UHS boron steel combinations could be improved by applying different innovative welding methods.

    The methods investigated where; three-pulsed welding, two-pulsed welding with force profile and using hollow-cone electrodes instead of regular electrodes. The different methods where evaluated with welding experiments and analysis of the nugget diameter, vicker hardness comparison and tensile strength test of welding nugget. The results from this thesis shows that the current window of three-sheet combinations with UHS boron steel can be significantly improved by using hollow-cone electrodes in RSW. The results also showed that the width of the current window varied depending on the depth of the hole in the electrode, a deeper hole improved the current window but also increased the oxide build-up.

    Applying a force profile with lowered electrode force during the welding sequence provided an improved process window compared to the constant electrode force when welding a three-sheet combination containing AlSi-coated boron steel.

    A three-pulse welding sequence performed better than the reference two-pulse welding schedule but still not good enough to meet VCC acceptance criteria. 

  • Sjölander, Andreas
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Utvärdering av fältmetod för mätningar på sprutbetong2019Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    I den här rapporten redovisas resultat från en utvärdering av nya fältmetoder för att mäta rörelser på sprutbetong i fält. Syftet var att föreslå en metod som är snabb och pålitlig och därmed användbar för att mäta deformationer i sprutbetong under pågående produktion. Först utvärderas mekanisk mätning med skjutmått och mikrometer. Tanken var att dessa instrument skulle användas för att mäta rörelser som uppstod mellan mätpunkter inom ett uppmarkerat mätområde på sprutbetongen. Metodens noggrannhet utvärderades i labbmiljö genom att mäta rörelsen mellan inskjutna spikar i en betongbalk som utsattes för uttorkningskrympning. Handhavandet av mikrometern gjorde att metodens repeterbarhet var låg och osäkerheten i de genomförda mätningarna var större än den deformation som skulle mätas. Att använda sig av mekaniska instrument som skjutmått eller mikrometerskruv är därför inte en lämplig metod att använda i fält. Därefter utvärderades fotogrammetri, som på senare år har blivit en allt mer populär metod för att i labb mäta deformationer av betong i samband med belastningsförsök. Tekniken Digital Image Correlation (DIC) och programmet PY2DIC, som bygger på öppen källkod och är utvecklat av avdelningen för Geodesi och Geoinformatik vid universitetet La Sapienza i Rom, har använts för att analysera deformationerna. Resultat presenterade i den här rapporten visar att deformationsmätningar kan genomföras med hög noggrannhet med en standard systemkamera och med betongens textur som enda referens. Det betyder att inga markörer på betongens yta behöver användas för att genomföra mätningarna. Baserat på två bilder tagna ifrån liknande positioner kan PY2DIC beräkna skillnaden i kamerans position för att särskilja kamerans translation ifrån betongens deformation. Detta utvärderas genom att jämföra deformationen av en betongbalk testad i labbmiljö med en fast monterad kamera och en kamera som mellan varje bild flyttades enligt ett fast schema. Under förutsättning att kamerans nya position är inom några centimeter visade dessa försök att god noggrannheten kunde uppnås med den rörliga kameran. Slutligen användes en rörlig kamera för att mäta sprutbetongens deformation i tunnelmiljö under 8 veckor samt att utvärderade en metod för att övervaka sprickors propagering i fält. Den här rapporten har visat att fotogrammetri har stora möjligheter att kunna användas för att mäta deformationer av sprutbetong i fält. Mätningar med hög noggrannhet kan genomföras under förutsättning att en fast monterad kamera används. Projektet har visat att det finns goda möjligheter att genomföra deformationsmätningar i fält med en rörlig kamera men fortsatt forskning krävs innan en praktiskt tillämpningsbar metod kan presenteras. Vidare har en metod för att kunna övervaka propageringen av sprickor i tunnlar med fotogrammetri presenterats. Denna metod kan få stor praktisk nytta och har potential att automatisera övervakningen av sprickor under tunnelns driftskede.

  • Abuasbeh, Mohammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Acuña, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    ATES SYSTEM MONITORING PROJECT, FIRST MEASUREMENT AND PERFORMANCE EVALUATION: CASE STUDY IN SWEDEN2018In: Proceedings of the IGSHPA Research Track 2018, 2018Conference paper (Refereed)
    Abstract [en]

    Performance of Aquifer Thermal Energy Storage (ATES) systems for seasonal thermal storage depends on the temperature of the extracted/injected groundwater, water pumping rates and the hydrogeological conditions of the aquifer. ATES systems are therefore often designed to maintain a temperature difference possible between the warm side and cold side of the aquifer, without risking hydraulic and thermal intrusion between them or thermal leakage to surrounding area, i.e. maximize hydraulic and thermal recovery. Monitoring the operation of pumping and observation wells is crucial for the validation of ATES groundwater models utilized for their design, and measured data provides valuable information for researchers and practitioners working in the field. After months of planning and installation work, selected measurements recorded in an ATES monitoring project in Sweden during the first three seasons of operation are reported in this paper. The ATES system is located in Solna, in Stockholm esker, and it is used to heat and cool two commercial buildings with a total area of around 30,000 m 2 . The ATES consists of 3 warm and 2 cold pumping wells that are able to pump up to 50 liters per second. The monitoring system consists of temperature sensors and flow meters placed at the pumping wells, a distributed temperature-sensing rig employing fiber optic cables as linear sensor and measuring temperature every 0.25 m along the depth of all pumping and several observation wells, yielding temporal and spatial variation data of the temperature in the aquifer. The heat injection and extraction to and from the ground is measured using power meters at the main line connecting the pumping wells to the system. The total heat and cold extracted from the aquifer during the first heating and cooling season is 190MWh and 237MWh, respectively. A total of 143 MWh of heat were extracted during the second heating season. The hydraulic and thermal recovery values of the first year of operation was 1.37 and 0.33, respectively, indicating that more storage volume (50500m3 ) was recovered during the cooling season than injected (36900m3 ) in the previous heating season. The DTS data showed traces of the thermal front from the warm storage reaching the cold one. Only 33% of the thermal energy was recovered. These losses are likely due to ambient groundwater flow as well as conduction losses at the boundaries of the storage volume. Additionally, the net energy balance over the first year corresponds to 0.12 which indicates a total net heating of the ATES over the first year. It is recommended to increase the storage volume and achieve more hydraulic and thermal balance in the ATES system. This can enhance the thermal recovery and overall performance. Continuous monitoring of the ATES is and will be ongoing for at least 3 more years. The work presented in this paper is an initial evaluation of the system aiming to optimize the ATES performance.

  • Abuasbeh, Mohammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn (Editor)
    KTH, Superseded Departments (pre-2005), Energy Technology. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Aquifer Thermal Energy Storage Insight into the future2018Report (Refereed)
    Abstract [en]

    Underground Thermal Energy Storage (UTES) systems, such as Aquifer thermal energy storage(ATES) are used in several countries. The regulation and research on the potential impacts of ATESon groundwater resources and the subsurface environment often lag behind the technologicaldevelopment of an ever-growing demand for this renewable energy source. The lack of a clear andscientifically supported risk management strategy implies that potentially unwanted risks might betaken at vulnerable locations such as near well fields used for drinking water production. At othersites, on the other side, the application of ATES systems is avoided without proper reasons. Thisresults in limiting the utilization of the ATES technology in many occasions, affecting the possibilityto increase the share of renewable energy use. Therefore, further studies to characterizegroundwater resources, performance monitoring and identification of environmental impacts areneeded to understand the advantages and limitations of ATES systems.

    The environmental impact and technical performance of a Low Temperature ATES (LT-ATES)system in operation since 2016 is presented. The system is called Rosenborg and is owned byVasakronan. It is located in the northern part of Stockholm, on a glaciofluvial deposit called theStockholm esker. The ATES system is used to heat and cool two commercial buildings with a totalarea of around 30,000 m2. The ATES consists of 3 warm and 2 cold pumping wells that are able topump up to 50 liters per second.

    Analysis of groundwater sampling included a period of 9 months prior to ATES operation as well asthe first full season of heating and cooling operation. The sampling was conducted in a group ofwells in the vicinity of the installation and within the system. Means of evaluation constituted astatistical approach that included Kruskal-Wallis test by ranks, to compare the wells before and afterthe ATES was used. Then principal component analysis (PCA) and clustering analysis were used tostudy the ground water conditions change before and after the ATES. Aquifer Variation Ratio(AVR) was suggested as mean to evaluate the overall conditions of the aquifer pre- and post- ATES.

    The results showed some variations in redox potential, particularly at the cold wells which likely wasdue to the mixing of groundwater considering the different depths of groundwater beingabstracted/injected from different redox zones. Arsenic, which has shown to be sensitive to hightemperatures in other research showed a decrease in concentration. A lower specific conductivityand total hardness at the ATES well compared to their vicinity was found. That indicates that theyare less subject to salinization and that no accumulation has occurred to date. It is evident that theenvironmental impact from ATES is governed by the pre-conditions in soil- and groundwater. ThePCA and clustering analysis showed very little change in the overall conditions in the aquifer whencomparing the ATES before and after operation. Temperature change showed negligible impact.This can be mainly attributed to the relatively small temperature change (+6 and – 5 degrees) fromthe undisturbed Aquifer temperature which is 10.5°C.

    Performance of Aquifer Thermal Energy Storage (ATES) systems for seasonal thermal storagedepends on the temperature of the extracted/injected groundwater, water pumping rates and thehydrogeological conditions of the aquifer. ATES systems are therefore often designed to work witha temperature difference between the warm side and cold side of the aquifer without riskinghydraulic and thermal intrusion between them, and avoiding thermal leakage to surrounding area, i.e. optimize hydraulic and thermal recovery. The hydraulic and thermal recovery values of the first yearof operation in Rosenorg weres 1.37 and 0.33, respectively, indicating that more storage volume(50500m3) was recovered during the cooling season than injected (36900m3) in the previous heatingseason.

    Monitoring the operation of pumping and observation wells is crucial for the validation of ATESgroundwater models utilized for their design, and measured data provides valuable information forresearchers and practitioners working in the field. After months of planning and installation work,selected measurements recorded in an ATES monitoring project in Sweden during the first threeseasons of operation are reported in this report.

    The monitoring system consists of temperature sensors and flow meters placed at the pumpingwells, a distributed temperature-sensing rig employing fiber optic cables as linear sensor andmeasuring temperature every 0.25 m along the depth of all pumping and several observation wells,yielding temporal and spatial variation data of the temperature in the aquifer. The heat injection andextraction to and from the ground is measured using power meters at the main line connecting thepumping wells to the system. The total heat and cold extracted from the aquifer during the firstheating and cooling season is 190MWh and 237MWh, respectively. A total of 143 MWh of heatwere extracted during the second heating season. The hydraulic and thermal recovery values of thefirst year of operation was 1.37 and 0.33, respectively, indicating that more storage volume(50500m3) was recovered during the cooling season than injected (36900m3) in the previous heatingseason. The DTS data showed traces of the thermal front from the warm storage reaching the coldone. Only 33% of the thermal energy was recovered. These losses are likely due to ambientgroundwater flow as well as conduction losses at the boundaries of the storage volume. Additionally,the net energy balance over the first year corresponds to 0.12 which indicates a total net heating ofthe ATES over the first year. It is recommended to increase the storage volume and achieve morehydraulic and thermal balance in the ATES system. This can enhance the thermal recovery andoverall performance. Continuous monitoring of the ATES is and will be ongoing for at least 3 moreyears. The work presented in this report is an initial evaluation of the system aiming to optimize theATES performance.

    Furthermore, data management and processing tool has been established for the ATES system in Rosenborg. Additionally, a conceptual model of the ATES area has been established. Current andfuture work is focussed on completing a full scale numerical model in FEFLOW and validated themodel (both hydraulically and thermally) with the available monitoring data. Furthermore,establishing recommendations for optimum design and operation of ATES system.

  • Karuppasamy, Arun Prasath
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    Stenlåås, Ola
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. Scania CV AB, Sweden.
    Bernemyr, Hanna
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    Christiansen Erlandsson, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    Agglomeration and Nucleation of Non-VolatileParticles in a Particle Grouping Exhaust Pipe of a Euro VI Heavy-Duty Diesel Engine2019Conference paper (Refereed)
    Abstract [en]

    The possibility of non-volatile particle agglomeration in engine exhaust was experimentally examined in a Euro VI heavy duty engine using a variable cross section agglomeration pipe, insulated and double walled for minimal thermophoresis. The agglomeration pipe was located between the turbocharger and the exhaust treatment devices. Sampling was made across the pipe and along the centre-line of the agglomeration pipe. The performance of the agglomeration pipe was compared with an equivalent insulated straight pipe. The non-volatile total particle number and size distribution were investigated. Particle number measurements were conducted according to the guidelines from the Particle Measurement Programme. The Engine was fuelled with commercially available low sulphur S10 diesel. Experiments conducted in heavy duty engine relevant operating points were done to sweep the effect of (i) Mass flow rate in the exhaust (ii) Temperature in the exhaust and (iii) Engine speed and thus exhaust pressure pulsation frequencies in the exhaust. The test matrix included eleven operating points at steady-state. The results show that, using the agglomeration pipe, neither significant non-volatile particle reduction nor noticeable change in particle size distribution could be proven. In the current study, nucleation of non-volatile particles could not be observed along the straight pipe. Furthermore, it was found that the variable cross-section agglomeration pipe and straight pipe showed similar results in the total particle number and particle size distribution with respect to non-volatile particles.

  • Zhou, Zhou
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Neuronic Engineering.
    Li, Xiaogai
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Neuronic Engineering.
    Biomechanics of acute subdural hematoma in the elderly: A fluid-structure interaction study2018In: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042Article in journal (Refereed)
    Abstract [en]

    Acute subdural hematoma (ASDH) due to bridging vein (BV) rupture is a frequent and lethal head injury, especially in the elderly. Brain atrophy has been hypothesized to be a primary pathogenesis associated with the increased risk of ASDH in the elderly. Though decades of biomechanical endeavours have been made to elucidate the potential mechanisms, a thorough explanation for this hypothesis appears lacking. Thus, a recently improved finite element head model, in which the brain-skull interface was modelled using a fluid-structure interaction (FSI) approach with special treatment of the cerebrospinal fluid as arbitrary Lagrangian-Eulerian fluid formulation, is used to partially address this understanding gap. Models with various degrees of atrophied brains and thereby different subarachnoid thicknesses are generated and subsequently exposed to experimentally determined loadings known to cause ASDH or not. The results show significant increases in the cortical relative motion and BV strain in the atrophied brain, which consequently exacerbates the ASDH risk in the elderly. Results of this study are suggested to be considered while developing age-adapted protecting strategies for the elderly in the future.

  • Strand, Filip
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Latent Task Embeddings forFew-Shot Function Approximation2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Approximating a function from a few data points is of great importance in fields where data is scarce, like, for example, in robotics applications. Recently, scalable and expressive parametric models like deep neural networks have demonstrated superior performance on a wide variety of function approximation tasks when plenty of data is available –however, these methods tend to perform considerably worse in low-data regimes which calls for alternative approaches. One way to address such limitations is by leveraging prior information about the function class to be estimated when such data is available. Sometimes this prior may be known in closed mathematical form but in general it is not. This the-sis is concerned with the more general case where the prior can only be sampled from, such as a black-box forward simulator. To this end, we propose a simple and scalable approach to learning a prior over functions by training a neural network on data from a distribution of related functions. This steps amounts to building a so called latent task embedding where all related functions (tasks) reside and which later can be efficiently searched at task-inference time - a process called fine-tuning. The pro-posed method can be seen as a special type of auto-encoder and employs the same idea of encoding individual data points during training as the recently proposed Conditional Neural Processes. We extend this work by also incorporating an auxiliary task and by providing additional latent space search methods for increased performance after the initial training step. The task-embedding framework makes finding the right function from a family of related function quick and generally requires only a few informative data points from that function. We evaluate the method by regressing onto the harmonic family of curves and also by applying it to two robotic systems with the aim of quickly identifying and controlling those systems.

  • TANG, Yihao
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    ZHU, Hui
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Test method development by use of SOM-GRNN2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The relationship between Objective Metrics (OM) and Subjective Assessments (SA) has been analyzed by people using different methods. This paper continues Gaspar Gil Gómez’s research over test method development by use of SOM-GRNN, aiming to find correlations between OM and SA. In this paper, CAE simulation is performed to analyze the relationship between OM and vehicle parameters. First impression test is refined and one more dataset has been added in order to populate SOM-GRNN map. This paper also conducts analysis over SOM and GRNN algorithms, and explores several possible applications using SOM-GRNN map. Finally the whole SOM-GRNN system is integrated and a User Interface is built in GUI for future research and application. The system can still be improved by populating database, refining SA evaluation method and optimizing SOM-GRNN training algorithms.

  • Tamayo Cascan, Edgar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Towards using microscopic traffic simulations for safety evaluation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Microscopic traffic simulation has become an important tool to investigate traffic efficiency and road safety. In order to produce meaningful results, incorporated driver behaviour models need to be carefully calibrated to represent real world conditions. In addition to macroscopic relationships such as the speed-density diagram, they should also adequately represent the average risk of accidents occurring on the road. In this thesis, I present a two stage computationally feasible multi-objective calibration process. The first stage performs a parameter sensitivity analysis to select only parameters with considerable effect on the respective objective functions to keep the computational complexity of the calibration at a manageable level. The second stage employs a multi-objective genetic algorithm that produces a front of Pareto optimal solutions with respect to the objective functions. Compared to traditional methods which focus on only one objective while sacrificing accuracy of the other, my method achieves a high degree of realism for both traffic flow and average risk.

  • Perinciolo, Paolo
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Sondhi, Eshwar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Model Based HandlingAnalyses2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis consists of building vehicle models for lateral dynamics that provide accurate results, while being simple enough to highlight clear relationships between vehicle properties and handling behaviours. The approach that characterizes the present work is built on the foundations provided by the bicycle, or single-track, model (STM). Nonetheless, its developments and improvements substantially differ from the usual sequence found in literature. Most studies based on this analytical vehicle model satisfy the quest for increased robustness by involving nonlinear description of the contact forces generated between tyres and ground.

    The presented analysis, instead, embraces the challenge of using completely linear models to describe vehicle lateral dynamics in a variety of driving situations. Hence, the aim of this thesis is to provide the reader with a deeper understanding of the effects of various physical properties on the actual dynamic behaviour, by complementing numerical correlations obtained from simulation outputs with analytical descriptions of their causes. The first step of the presented work deals with the selection and design of driving scenarios aiming at comprehensively evaluating vehicle handling, as well as defining the boundaries of the investigation. As in most engineering problems, a compromise has to be sought, since the set of maneuvers has to be broad enough to point out various dynamic characteristics, while limiting the time needed to perform evaluation of a real vehicle. Furthermore, the space occupation of each maneuver must allow execution in an actual testing facility. The design of suitable driving scenarios triggers an iterative process, in which the initial formulation of the single-track model is complemented with additional states and sources of complexity, based on the limitations that simulation outcomes point out. A complex model, previously built with the aid of Multi-Body Dynamics software, is initially accepted as a \black box", and adopted as a reference to estimate qualities and deficiencies of the results. The next step of the work deals with physical vehicle testing and correlation. After post-processing the data and comparing it to the analytical vehicle model, it is seen that the vehicle model represents the physical vehicle behaviour very well. The area where the model lacks is in transients, which in-turn can be explained by the lack of compliance in the system. The last part of the thesis brie y touches upon the vehicle behaviour in a dynamic driving simulator along with effects of motion cueing gains.

  • Persson, Milton
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Transient Dynamics and Core Tunneling in Vertical Spin-Vortex Pairs2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Spin-vortices in vertically spaced pairs of thin elliptical Permalloy nanoparticles are investigated. The two vortex cores with parallel out-of-plane magnetization exhibit a strong monopole-like attraction through the spacer much thinner than the core length, thus forming a bound core-core pair. The material of the spacer is designed to suppress both direct and indirect exchange interactions, so the remaining inter-vortex coupling is purely dipolar. In the investigated vortex pairs, the in-plane magnetization in the vortex periphery, outside the vortex cores, curl in opposite directions (have opposite chirality). As a result, the two cores move in opposite directions in response to an in-plane magnetic field, the Zeeman effect of which acts to decouple the core-core pair. This leads to unique dynamics of the spin-vortex parallel-core/antiparallel-chirality pair, which strongly depend on whether the pair is coupled or decoupled. In the coupled state, the cores are held close together by the core-core attraction, which results in short-radius oscillations and a resonance frequency of about 2 GHz for the main rotational eigen-mode. In the decoupled state, the cores are separated by a distance much greater than the core length and gyrate independently with a resonance frequency of the order of 100 MHz.

    The dynamics of the vortex pair are investigated at 77 K, where there is a bistability between the coupled and decoupled core states. Resonant excitations are used to decouple the cores with pulses of ∼10 Oe in amplitude and ∼100 ps in duration. The ability to decouple a vortex pair using such fast low-power pulses can be useful for multifrequency oscillators and vortex based memory.

    A search for quantum effects is undertaken at sub-Kelvin temperatures using a dilution refrigerator. Square pulses of 100 ns duration and amplitudes of the order of 1 Oe are applied in-plane to bring the system closer to decoupling, giving the cores a chance to tunnel through the barrier between the coupled and decoupled states. The amplitude required for decoupling is measured as a function of temperature and a leveling off in the decoupling probability is seen below 400 mK, giving some indication of core tunneling. Macroscopic quantum tunneling of magnetization is interesting from the fundamental physics point of view, e.g., as a model system for studying the measurement paradox in quantum mechanics, as well as for current and future computer technology in terms of understanding the ultimate limitations of miniaturizing magnetic memory elements.

  • Mounzer, Raid
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Improving simulators’ driving experience through objective metrics and subjective assessments2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     As the challenge grows in the vehicle industry, tightening the margins on financial and environmental costs of the vehicle development, computer aided engineering becomes more and more attractive. Extensive work is being invested in creating detailed models that can replicate vehicle behaviour accurately and efficiently. The work in this thesis starts with studying objective and subjective evaluations of vehicles as well as their counterparts in vehicle models and a simulator environment. Then, it continues to locate the weaknesses in the models, and investigate the possible improvements. The first part of the thesis focused on performing a literature study concerning the objective metrics and their use in the vehicle industry, as well as the use of simulators. This served as a foundation for the use of objective metrics in the validation of the CarRealTime models. The tools used in the thesis were also introduced. The work continued with the study of previously collected data concerning vehicle evaluation through subjective assessment and objective metrics, with different anti-roll bar configurations, to build trust in the ability of the drivers in evaluating these criteria. Similar data from the CarRealTime models and the simulator were also studied. The aim was to evaluate the simulator driving experience accuracy through the subjective assessment. The weaknesses of the model were identified, and an improved steering model was introduced, replacing the old lookup tables with a Pfeffer model from CarRealTime combined with the steering assist unit in Simulink. An extensive parameter study was performed to understand the effect of selected parameters on the driving experience. Using the same model, the simulator delays were studied in terms of replicating yaw and lateral movements, and how this can affect the driver’s perception of the driving experience. Finally, the results from the parameter study were used to assign the weight parameters in the optimization objective function where the goal was to study the possibility of improving the accuracy of the driving experience as well as counteracting the effects of simulator delays. The Matlab Optimization Toolkit was used in the process. As a conclusion, it was shown that the subjective assessment together with the objective metrics played a crucial role in identifying model and simulator weaknesses. The parameter study showed promising opportunities in solving the aforementioned issues, with the optimization tool and boundaries needing more elaborate work to reach conclusive results.

     

  • Kittane, Santusht Vasuki
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Harinath, Preetham
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    An evasive manoeuvre assist function for over-reactive drivers2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Previous studies have shown that many drivers are unable to provide the right amount of steering torque when facing an imminent collision with an upcoming obstacle. In some cases, drivers under-react i.e., they provide too low steering inputs and thus collide with the obstacle in front; in other cases, drivers might apply a higher steering input than necessary, potentially resulting in the vehicle leaving the road or losing stability. The EMA function is an active safety feature which has the sole objective of providing steering torque interference when performing such a manoeuvre. The motivation for the thesis work is to overcome some limitations of the existing MA function which does not incorporate the ability to differentiate driver reactions. In this thesis, an Evasive Manoeuvre Assist (EMA) function is designed to adapt to both types of the drivers, by an optimised steering torque overlay. The existing current EMA function is always amplifying the driver steering inputs using a feed-forward controller. The focus of this thesis work is to identify and dene a proper steering sequence reference model for closed-loop feedback control design. A simple single-point preview model is designed first to calculate the reference steering angle. A few test scenarios are set-up using the IPG CarMakerTMsimulation tool. The reference model is then tuned with respect to the amplitude and frequency by batch simulations to obtain the optimal steering prole. A feedback controller is then designed using this reference model. The controller is implemented in a real-time environment, using a Volvo rapid-prototype test vehicle. Preliminary variation tests have shown that the developed controller can enhance both an over-reacting and under-reacting driver's performance during an evasive manoeuvre, by applying assistance/resistance EPAS torque timely. The designed EMA function is shown to accommodate different driver reactions and provide intuitive torque interference. As opposed to the earlier notion that the EMA function only assists the driver with an additional steering wheel torque, it was shown that the optimal steering torque overlay might be in the form of assistance or resistance.

  • BHANA, MOAAJ
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Trajectory generation for safe overtaking maneuver inautonomous vehicles: Evaluated in lane merging scenario utilizing a trajectory planner2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     More than 1.2 million people die each year due to road traffic injuries [1]. In order to reduce traffic accidents and human errors, autonomous vehicles is been the subject of intense research. To improve the driving experience, automotive companies have developed Advanced Driver Assistance Systems (ADAS) such as Adaptive Cruise Control (ACC) and Lane Keeping Aid (LKA) which aim to make driving safer and more comfortable. One particularly interesting maneuver is the lane change. Lane change maneuver is one of the riskiest maneuvers that a driver has to perform on a highway, and can be perceived as challenging since it involves changes in both the longitudinal and lateral velocities, direction and as well as movement in the presence of other moving vehicles. This thesis seeks to evaluate how different prediction model of the trajectory planner will affect collision risk, comfort and result in an increasing rate of successful overtakes. An trajectory-planning algorithm will be reliable in making smarter decisions for performing a safe overtaking maneuver’s and constantly generate discrete trajectory profile with respect to the parameters of the vehicle in front. Future motion is predicted using prediction models linking control inputs, vehicle properties and external conditions to the evolution of the state of the vehicle. The vehicle should be able to avoid collisions at the point of convergence where two lane road merges into a single lane road and therefore, motion only in the longitudinal direction is considered for the evaluation. The prediction model chosen for this thesis is constant acceleration (CA) and constant velocity (CV). The project is part of a large EU-project called SafeCOP (Safe Cooperating CyberPhysical Systems) usingWireless Communication which aims at developing a complete prototype of an intelligent transport system. A great amount of trajectory generation techniques have been surveyed and quartic polynomial is selected for trajectory generation as it has many benefits of having a low computational cost and the continuous concatenation of curves is possible. It is important in the trajectory planner to cancel out trajectories which would dynamically not be feasible and result in an increase risk of collision with the surrounding vehicle. The two chosen prediction models were evaluated for three different scenarios on which they are tested and their results is compared. For the different scenarios addressed in this thesis Constant Acceleration (CA) prediction model gave better result when compared to Constant Velocity (CV) prediction model and had an lower risk of collision which increases the number of successful overtakes. While doing so the jerk dynamic constraints were always considered to ensure that the trajectory generated are within the comfort zone of the passenger.

  • Hauksson, Hédinn
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Energy consumption of an off-road modified pick-up and the possibility of hybridisation or electrification2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Arctic Trucks have been modifying vehicles such as the Toyota Hilux, Toyota Land Cruiser, Isuzu D-Max, Nissan Patrol and Nissan Navara for over 25 years for special projects as well as for recreational purposes both in Iceland and other countries. Arctic Trucks started up as a sub-division for Toyota Iceland but became an independent company in 2005. Their capability to make off-road vehicles is well known, the Toyota Hilux AT38 being their flagship. It has been driven to both the magnetic north pole, the South Pole and various other remote places and is widely used for logistics in Icelandic highlands as well as other places both during summer and winter time. This M.Sc. project in vehicle engineering covers measurements of energy consumption of a modified Toyota Hilux AT38 2017 in order to determine if some improvements are possible when it comes to fuel consumption and the vehicles environmental impact by hybridisation or full electrification of the vehicle. Fuel consumption is measured in various on-road and off-road conditions (gravel, snow and asphalt). Calculations are made to estimate the effect on fuel consumption of the climate control in the vehicle cabin. Air drag coefficient and friction coefficient are estimated based on coast-down tests in real-life conditions. These factors are necessary to evaluate the total running resistance of the vehicle. These fuel consumption measurements show that the fuel consumption for off-road driving is quite high and since this type of vehicle also needs to be light, the advantages of hybridisation or full electrification need to be examined further. For highway and city driving, hybridisation might be feasible but many factors need to be looked at for that case as well. As of now, battery technology and lack of infrastructure are standing in the way of this type of electric or plugin hybrid vehicles, since these vehicles are used in environments where electricity or even fossil fuel is hard and expensive to reach.

  • Gowthaman, Rahul
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jagwani, Suhail
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Advanced bushing script program in MSC ADAMS2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis focuses on investigating and optimizing a bushing script implemented as a tool in MSC ADAMS/Car. The study provides an insight on the representation of a rubber bushing and identify parameters which can be used to define the properties of a bushing in a simulation environment such as ADAMS/Car. The tool being studied here can be used to implement different kind of bushings such as a hydro bushing and a general rubber bushing, but optimization was implemented for the rubber bushing only. With an increasing reliance on Computer Aided Engineering (CAE) tools in the designing process, it is necessary that the vehicle behaviour can be predicted without relying on physical testing. CAE tools reduces the need of prototypes and provides a faster approach to designing vehicles. MSC ADAMS/Car is one such tool, which has been used here to predict the vehicle dynamic behaviour, which will influence the ride, handling and comfort characteristics of the vehicle. Rubber bushings, which have been studied here, have a significant contribution to the overall stiffness of the vehicle and as such, it is imperative that the tool being used here, is accurate and makes the designing process easy. The rubber bushing can be imagined to be a combination of a non-linear elastic spring, a frequency dependent Maxwell component and an amplitude dependent frictional element. In order to ease the design of the bushing properties, a reduced number of input properties are used to calculate the bushing properties internally. While trying to validate the force hysteresis loop obtained through the model with the measured data, it was seen that the accuracy was quite poor for the model when loading it with dynamic loads corresponding to amplitudes of0.2 mm and lower. The quasi-static loading and dynamic loading above 0.2 mm is shown to have a satisfactory accuracy when compared to the measured data.

  • Public defence: 2019-03-01 10:00 FD5 The Svedbergsalen, Stockholm
    Nilebäck, Linnea
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Expanded knowledge on silk assembly for development of bioactive silk coatings2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Silk is a fascinating natural material made from proteins that self-assemble through structural rearrangements into one of the toughest materials known. As silk is protein-based, durable and elastic, it has many features that makes it suitable as a scaffold material for tissue engineering. Natural silk proteins are complex and thus difficult to produce synthetically. Therefore, partial silk proteins have been designed for production in heterologous host cells such as expression strains of Escherichia coli. This thesis presents investigations of the properties of one such partial spider silk protein, 4RepCT, and its assembly process, and describes the development of bioactive silk coatings and their properties. The focus has been to develop coatings for implant surfaces to prevent infections and improve interactions with cells.

    In Paper I, the intrinsic properties and contribution to the self-assembly process of the two protein parts 4Rep and CT were investigated separately, in a mixture (4Rep+CT) and as a fusion protein (4RepCT). The results showed that assembly occurs both at the liquid-air and liquid-solid interfaces. CT reached the interface fast but did not refold to form β-sheets, characteristic for silk, on its own. 4Rep adsorbed rapidly, and extensive intermolecular interactions were formed, although unorganized. Covalent linkage between 4Rep and CT, as in 4RepCT, and thus close proximity between the two silk parts, was found to be crucial in order to obtain both conversion into β-sheet rich structures and a nanofibrillar topography of the adsorbed proteins.

    The finding that 4RepCT self-assembles into nanofibrillar coatings on solid surfaces could be useful for various applications, for example to improve implant surfaces. The coating process was thus further evaluated in Paper II, showing that the silk coatings were chemically resistant and could also be made from silk protein variants where additional peptide motifs had been fused to 4RepCT at the genetic level. Silk with a cell-binding motif (FN-silk) and an antimicrobial peptide (Mag-silk) could assemble onto titanium, stainless steel and hydroxyapatite, respectively, materials that are commonly used for implants. Fibroblasts and endothelial cells were successfully cultured on FN-silk coatings and proliferated well. Finally, coatings of Mag-silk were evaluated for their ability to prevent adhesion of Staphylococcus aureus.

    In Paper III, silk from silkworms were used to construct materials in three different formats suitable for wound healing applications. Microporous scaffolds, electrospun mats and thin coatings of silkworm silk could all be coated with 4RepCT. They thereby gained the functions added via 4RepCT fusion proteins with a cell-binding motif (FN-silk), an antibody binding domain (Z-silk) or an enzyme (Xyl-silk). This shows upon a versatile method for functionalization of materials in different formats with bioactive motifs and domains.

    In Paper IV, the aim was to develop dual-functional silk coatings to promote osseointegration and prevent bacterial adhesion to orthopedic and dental implants. Coatings of regular silk (4RepCT) and FN-silk were given additional functions by using the transpeptidase Sortase A to mediate conjugation with the biofilm dispersal enzyme Dispersin B, or the endolysins PlySs2 and SAL-1. The obtained coatings showed a reduced adhesion of S. aureus compared to regular silk and FN-silk. Moreover, osteosarcoma cells adhered and proliferated well on coatings of FN-silk also when conjugated with enzymes.

    Altogether, the work presented in this thesis suggests that 4RepCT silk coatings are valuable as a base for construction of bioactive surfaces. The coatings can be applied on many different surfaces, and the bioactive coatings developed herein show potential for wound healing applications and prevention of biomaterial-associated infections.

  • LILJA, JIMMY
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    PARK, SIMON
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Stop Guessing and Start Tracking: Guidelines for Measuring Sustainability Performance of Funds2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Conscious customers and the threat of regulations have compelled capital markets around the world to increase their sustainability focus. Today, a fund manager must know how to measure and communicate the sustainability of her fund’s portfolio, which raises the question of how such measurement should be designed? By interviewing decision makers at one of Sweden’s major fund management firms and examining existing sustainability metrics, we identify the key features practitioners want from a sustainability measurement and discuss how existing metrics relate to this. We find that there is an increased need for: (i) capturing the positive contributions the companies in the portfolio have towards a sustainable development, (ii) including each company’s internal capabilities, which reflects important information about the likelihood of future contributions, (iii) relevant peer groups in order to understand the context of a company’s score, and (iv) understanding that sustainability is not a one dimensional issue and therefore should not be treated as one. To meet this need, we argue that the emerging group of metrics based on the United Nations Sustainable Development Goals could be used as a complement to the currently used risk-focused sustainability metrics.

  • Wang, Zexu
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Trajectory Planning for Four WheelSteering Autonomous Vehicle2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work presents a model predictive control (MPC) based trajectory planner forhigh speed lane change and low speed parking scenarios of autonomous four wheel steering(4WS) vehicle. A four wheel steering vehicle has better low speed maneuverabilityand high speed stability compared with normal front wheel steering(FWS) vehicles. TheMPC optimal trajectory planner is formulated in a curvilinear coordinate frame (Frenetframe) minimizing the lateral deviation, heading error and velocity error in a kinematicdouble track model of a four wheel steering vehicle. Using the proposed trajectory planner,simulations show that a four wheel steering vehicle is able to track different type ofpath with lower lateral deviations, less heading error and shorter longitudinal distance.

  • Public defence: 2019-02-26 10:30 T1 (Emmy Rappesalen), Huddinge
    Kornevs, Maksims
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    Assessment of Application of Participatory Methods for Complex Adaptive Systems  in the Public Sector2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The provision of services by the public sector is the result of a complex adaptive system at work, and involves a large number of stakeholders from different institutions and organisations. In the era of rapid change in requirements and expectations from the public sector, the management of change processes asks for the involvement of many stakeholders from different layers and positions.

    Participatory methods provide the ability to involve a wide range of stakeholders, but despite their case-wise documented successes, and well described application in involving citizens in governmental decision-making, very little evidence exists of their role when engaging professionals.

    This study assesses the application of participatory methods as an approach to support change processes in the public sector from a complex adaptive system perspective. The purpose of this two-phase exploratory sequential mixed method study with descriptive parts is to first qualitatively explore which needs for change in the public sector could benefit from participatory methods, and then to apply participatory methods for six experiments to assess how effective such methods are to support change processes of complex adaptive systems in the public sector.

    Four methods have been included: participatory simulation, gamification, Q methodology and participatory model building. Each of the cases has been scored on a set of frameworks. The cases have been obtained from the fields of road networks, transit and healthcare.

    Analysis across the experiment found several trends. Firstly, experiments at the field-level, where expertise and knowledge outside one organisation are required, showed stronger democratisation and focus on mapping out diversity compared to other levels. Similarly, experiments at the sub-system level are more likely to be focused on reaching consensus and using participants for advising. Secondly, a pattern has been found between higher participatory level of a method, a higher degree of power-sharing between the participants, and better results of an assessment.  A correlation was observed between overall assessment and other parameters of applications: communication efficiency, knowledge between causes and effects, and direction from leadership.

    The recognition that the public sector is a complex adaptive system proved to be more present in the service-oriented fields than in the infrastructure fields. Larger-scale issues at the organisation-level or even field-level proved to be more complex than issues at the subsystem level.

    Participatory methods proved to be effective for providing a grip on issues of a complex nature. Particular strengths were the ability to provide for open structures for thinking outside the box, and the use for identification of bottlenecks and constraints in systems. The ability to identify differences in stakeholder perspectives proves valuable, and can be gathered from a wide range of sources in and around a participatory setting.

    However, successful participatory methods need high communication efficiency, use retroactive evaluation and need to be done based on high stakeholder collaboration. These costs can outweigh all benefits if the problem is not complex or preparation has not been appropriately performed. Access to the right people, support from the organisation and motivated participants, as well as the right choice for the level of participation proved crucial for its success.

  • Kölzow, Krister
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Method for rebuilding gaspoweredtrucks2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis investigates the possibility to rebuild heavy-duty trucks poweredby liquefied natural gas (LNG) to other fuel options such as compressednatural gas (CNG), diesel or ethanol. The background is that the second handvalue for a LNG truck is lower than a similar diesel truck due to an undevelopedinfrastructure with few refuelling stations. This results in a small market for secondhand LNG trucks.Both tractor and rigid trucks are evaluated from a technical perspective to determinewhich components that need to be changed when switching from LNG toanother type of fuel. When that is completed each fuel alternative is evaluatedbased on cost and market interest. Also certification and other legislations areinvestigated to determine if they will affect the rebuilding process.The result shows that the rebuild faces different technical complexity dependingon the target fuel alternative. It is concluded that a rebuild to diesel or ethanolis expensive due to many changes needed for the engine and aftertreatment andtherefore these alternatives are not a good choice for a rebuild. A rebuild to CNGis still expensive but can be of interest for rigid trucks, but not for tractor truckssince they usually have a demand for longer range. In order to get the final cost ofthe rebuild to CNG a commercial assessment has to be made and the rebuild willdepend on in which country the rebuild is performed due to different legislationsfor re-registration which may be a an obstacle.

  • Böhlander, Marcus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Design and Safety Analysis ofEmergency Brake System forAutonomous Formula Car: In Reference to Functional Safety ISO 262622018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The engineering competition Formula Student has introduced a Driverless Vehicle (DV)class, which requires the students to develop a car that can autonomously make its wayaround a cone track. To ensure the safety of such a vehicle, an Emergency Brake System(EBS) is required. The EBS shall ensure transition to safe state for detection of a singlefailure mode. This thesis work covers the design of the EBS for KTH Formula Student(KTH FS).Due to the safety critical character of this system, the software part of the EBS, calledEBS Supervisor, has been analyzed in accordance with the safety standard ISO 26262 tosee if an improved safety could be achieved. The analysis has been perform according toPart 3: Concept phase of ISO 26262 with an item definition, Hazard Analysis and RiskAssessment (HARA), Functional Safety Concept (FSC) and Technical Safety Concept(TSC).The result of the analysis showed that the EBS Supervisor requires extensive redundanciesin order to follow ISO 26262. This includes an additional CPU as well as signal checksof inputs and outputs. Due to limited resources in terms of money and time within theKTH FS team, these redundancies will not be implemented. The process of working withthe safety standard did however inspire an increased safety mindset.

  • Lattuada, Alessandro
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle design.
    Tire-induced vehicle pull2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Vehicle pull is an issue that occurs when the driver has to exert a discerniblesteering torque (pull) for the vehicle to run straight, otherwisea lateral drift takes place. This thesis deals with the straight motion ofroad vehicles, with particular focus on the role played by tire characteristics,road cross slope and interactions between tires and vehicle.A thorough theoretical approach has been adopted, adjusting thePacejka’s formulation for effective axle characteristics and extendingthe linear handling diagram theory. This has allowed to obtain innovativeanalytical expressions, describing the straight-driving slip anglesand steering torque offsets.The analytical expressions have been validated, together with asingle-track model, by means of quasi-static and dynamic simulationsof a full-vehicle model. Moreover, a relationship between tire characteristicsand on-center handling has been described, that relates objectivemetrics with subjective feedback.The obtained analytical expressions can be used by vehicle OriginalEquipment Manufacturers (OEMs) or Tire Suppliers for productdevelopment.

  • Johannessen, Markus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Concept Study and Design ofFloating Offshore Wind TurbineSupport Structure2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There is a need for renewable energy sources that can replace the non-renewable energy sourcesthat we use today. This is on the agenda as one of the United Nations sustainable developmentgoals. Embracing new technologies is addressed as one of the ways of achieving aordable,reliable, sustainable and modern energy for all. Oshore wind power has great potential as anenergy source, and development of the oating solutions is of special importance.In this report, key design parameters of oating oshore wind turbines are identied based ona literature study on research projects as well as on-going test turbines and wind farms. Thekey design parameters should be used for determining the type of technology suitable for aproject, as well as for guidance in the design phase.Based on the key design parameters, a conceptual design of a semisubmersible substructurehas been made for the DTU 10 MW reference wind turbine for a site outside the island ofBarra, west of Scotland. The substructure is a three column semisubmersible connected witha closed shape pontoon and no bracing. The wind turbine is placed on top of one of the threecolumns to reduce number of columns and utilize more of the structure.Variation of the column diameter and distance between the columns has been studied to ndsuitable main dimensions. Mass estimations has been made and the required amount of ballasthas been calculated for a set of combinations to select a conguration for further analysis.Hydrostatic and hydrodynamic analysis has been performed on the design to understand itscharacteristics in the ocean environment. Intact stability is considered in the hydrostatic analysis,and the hydrodynamic analysis includes a study of the motions, loads and accelerationsof the structure.

  • Schumacher, Viking Alex
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Jet Stream Velocity fromAzipod on Stadsgården: A Litterature Study of PIANC W.G. 180Application for Stadsgården2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ferry line company VIKING LINE has put in an order for a new vessel with a planned delivery for the year 2020. The vessel will berth and depart daily from the Stockholm port, Stadsgården. The vessel is equipped with two 10 MW Azipod propeller systems. This new propulsion system has the capability of rotating the direction of the propeller thrust 360° which is different from other vessels currently using the same port. The direction and distance of the propeller from the quay has raised concern at the Ports of Stockholm. The integrity and design of the quay wall at Stadsgården is to be related to the guidelines set in place by the World Association for Waterborne Transport Infrastructure (PIANC) Working Group 180: “Guidelines for Protecting Berthing Structures from Scour Caused by Ships.” The guidelines have been compared to the actuator disc theory in order to validate the initial jet stream velocity from the new propeller system. The propagation of the jet stream was later analyzed and a velocity at the quay wall is calculated. A lack of information from certain parameters in the guidelines has led to implementations of assumptions. Uncertainties in the methods and equations presented by the guidelines are discussed. Overall, the guidelines were applicable in the investigation of the new vessel at Stadsgården. The jet stream velocity from the new vessel is compared to the velocity from a similar vessel currently using the same berthing structure. From the comparison it is seen that the berthing structure will be exposed to velocities four times larger than the current jet stream velocities at Stadsgården. A list with recommended action that can be performed by the Ports of Stockholm is presented.

  • Mehdi Pour, Reza
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Transmission DynamicsModelling: Gear Whine Simulation Using AVL Excite2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, increasing pressure from legislation and customer demands in the automotive industry are forcing manufacturers to produce greener vehicles with lower emissions and fuel consumption.As a result, electrified and hybrid vehicles are a growing popular alternative to traditional internal combustion engines (ICE). The noise from an electric vehicle comes mainly from contact between tyres and road, wind resistance and driveline. The noise emitted from the driveline is for the mostpart related to the gearbox. When developing a driveline, it is a factor of importance to estimate the noise radiating from the gearbox to achieve an acceptable design.Gears are used extensively in the driveline of electric vehicles. As the gears are in mesh, a main intrusive concern is known as gear whine noise. Gear whine noise is an undesired vibroacoustic phenomenon and is likely to originate through the gear contacts and be transferred through themechanical components to the housing where the vibrations are converted into airborne and structure-borne noise. The gear whine noise originates primarily from the excitation coming from transmission error (TE). Transmission error is defined as the difference between the ideal smoothtransfer of motion of a gear and what is in practice due to lack of smoothness.The main objective of this study is to simulate the vibrations generated by the gear whine noise in an electric powertrain line developed by AVL Vicura. The electric transmission used in this study provides only a fixed overall gear ratio, i.e. 9.59, under all operation conditions. It is assumed thatthe system is excited only by the transmission error and the mesh stiffness of the gear contacts. In order to perform NVH analysis under different operating conditions, a multibody dynamics model according to the AVL Excite program has been developed. The dynamic simulations are thencompared with previous experimental measurements provided by AVL Vicura.Two validation criteria have been used to analyse the dynamic behaviour of the AVL Excite model: signal processing using the FFT method and comparison with the experimental measurements.The results from the AVL Excite model show that the FFT criterion is quite successful and all excitation frequencies are properly observed in FFT plots. Nevertheless, when it comes to the second criterion, as long as not all dynamic parameters of the system such as damping or stiffnesscoefficients are provided with certainty in the model, it is too difficult to investigate the accuracy of the AVL Excite model. Another investigation is a numerical design study to analyses how the damping coefficients influence the response. After reducing the damping parameters, the results show that the housing and bearings have the highest influence on the response. If more acceptable results are desired,future studies must be concentrated on these to obtain more acceptable damping values.

  • Ruiz Cayuela, Sergio
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    Rejecting Fate: The challenge of a subaltern community to the creation of a sacrifice zone in Can Sant Joan, Catalonia2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It was my first visit ever to the neighborhood association – in February 2017 – and the phone rang again in the contiguous room. “I’m sorry” apologized José Luis “but our colleagues are not here yet and I need to answer the phone”. Manolo, who stayed with me, responded to my curious look: “we just sent the monthly invoice of the cooperative committee of funerals and this month is higher than usual. Three people died only last week. The neighbors are calling to check if the invoice is right, and some of them are trying to postpone the payment. But we try not to do exceptions, it’s the only way to keep working”. When José Luis came back, they both explained to me what exactly was the cooperative committee of funerals. Facing an increase in the number of deceased people and the high expense that is usually incurred by families in burial services, in 1987 the neighborhood association came up with the idea of creating a group of people that would share those costs. The project, though, would only make sense with widespread support from the community. Despite the strict age limit of 50 years old, almost 4.000 people responded when the call was launched, and the number of associates has remained steady through the years. This anecdote reflects very well the identity of the Can Sant Joan community, to which José Luis and Manolo passionately introduced me during that first meeting. The two men talked straight about the many social and environmental problems that the neighborhood had faced during the years and the ways in which the community had organized to confront them. Yet, they did not speak in a plaintive way, their speech challenged corporate and institutional power and claimed fearlessly for social justice. The Can Sant Joan community – not unlike many others in the Vallès region – has faced many adversities of different kind since its very creation, but its inhabitants have always confronted them and have restlessly fought for improving the living conditions in the neighborhood. Can Sant Joan stands out among other sacrifice zones in the Vallès area because of the long list of locally unwanted land uses that is burdened with, but especially because of its strong subaltern identity that has led the community to partially revert their condition.

    My research is grounded on the acknowledgment of Can Sant Joan’s environmental and social burdens, as a representation of all those communities around the world whose livelihoods are contaminated and impoverished in the name of neoliberal capitalism, and especially to those that decide to stand up and fight against power inequalities and social injustices. I foresee my research not just as an intellectual exercise, but as a process grounded in real life experiences of contamination and neglect that ultimately seeks to make a difference in the community, where it starts. This study is, thus, a transdisciplinary – almost antidisciplinary – piece where different disciplines with ambitions of challenging the sociopolitical status quo in order to achieve social and environmental justice intertwine. My research is built on existing literature in the fields of subaltern environmentalism – and other forms alternative environmentalism – political ecology and environmental humanities. Much have been written about polluted communities in different fields, but there are still crucial gaps that need to be filled. My ambitions are to better understand the sociopolitical processes that lead to the creation of sacrifice zones, to expand the definition of violence by uncovering different forms of slow violence that take place in them, to analyze the environmental movements embraced by affected communities, and to evaluate the potential benefits

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    that a subaltern environmental movement could have to those communities. The outcome of my research will be shared with the movement against waste incineration of Can Sant Joan and with the community in an attempt to realize the main aspiration of my research: to inform and enhance the activist movement in the neighborhood. This will be done by co-organizing at least one public event in the neighborhood together with members of the movement against incineration, in which the outcomes of my research will be presented to the local audience. Additionally, I keep personal relationship with the key informants, who have been integrated in the activist-scholar circle of the KTH Environmental Humanities Laboratory. If successful, this study could be the first stage of an action research in which local activists would not only be treated as a group of study, but their needs and actions would reframe the questions and scope of my research. In turn, the local movement against incineration would make use of the research outcomes in order to reach its goal, eventually creating a symbiotic feedback process potentially fruitful for both parts.

    This study is organized in seven chapters and six interludes. In chapter 2 I present the rationale behind the choice of case study as a research methodology, introduce the writer to the case study design, and share the ethical considerations at stake. Chapter 3 contains the theoretical toolbox where I conduct a literature review of the material that serves as theoretical frame for this study. I start with different visions on subalternity to later define subaltern environmentalism, and pointing out to some commonalities among different forms of alternative environmentalism. Then, I explore the concept of sacrifice zone and present the street science process that is being used by affected communities in order to uncover the infliction of slow violence in a variety of forms. In chapter 4 I introduce the reader to the case study through a short historical revision of the origins of Can Sant Joan and the development of the neighborhood until our days. Thereafter I thoroughly analyze the socio-political positionality of the community in different terms to verify if Can Sant Joan is a subaltern community. Chapter 5 is dedicated to discussing the neighborhood of Can Sant Joan as a sacrifice zone, as well as different forms of slow violence that the community has suffered. First, I revise the long list of locally unwanted land uses (LULUs) that the community has been burdened with and uncover a pattern based on political criteria for the placing of those LULUs. Thereupon, I analyze the different forms of slow violence that Can Sant Joan is being inflicted, including environmental, structural and narrative violence. In chapter 6, I document the movement against waste incineration in the cement plant that is taking place in Can Sant Joan, present the main forms of activism that the movement is using, and discuss the features that make it fit into the frame of subaltern environmentalism. Then, I discuss the central role of street science and forming coalitions: while the former is used to contest narrative violence and legitimize the claims of the community, the latter enhances public visibility and helps to forge a common subaltern identity that goes beyond the borders of the neighborhood. The study concludes with chapter 7, where I summarize the outcomes of this thesis by answering the research questions posed in chapter 2. Finally, I briefly present potential future research in Can Sant Joan that could keep contributing to the mobilized scholarly fields and to the movement against incineration as well, and close with a short update of the last months of struggle. The study is complemented with a series of six

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    interludes inspired by the Toxic Bios1 project, which compiles in an interactive open access online platform toxic autobiographies from communities affected by environmental injustices in several European countries and beyond. In the interludes the scale of the unit of analysis shifts from the community of Can Sant Joan to the individuals affected by the studied phenomena and thus, I use storytelling in order to complement my research with insights from a different perspective. In the first interlude, I highlight the importance that bodily experiences of toxicity can have in contesting narrative violence through toxic storytelling and I discuss the new guerrilla narrative methodology. The rest of the interludes comprise six toxic autobiographies by six different members of the local community that are to different extents active in the movement against waste incineration in Can Sant Joan.

  • Handberg, Leif
    et al.
    KTH, School of Computer Science and Communication (CSC), Media Technology and Graphic Arts, Media (closed 20111231).
    Jonsson, Alex
    KTH, School of Computer Science and Communication (CSC), Media Technology and Graphic Arts, Media (closed 20111231).
    Knudsen, Claus
    Høgskolen i Lillehammer, Gudbrandsdalsvegen 350, NORWAY.
    Living with a continuously produced presence – experiences from an extended office space.2007Conference paper (Refereed)
    Abstract [en]

    What is it actually like to share your office space - all day, every day - in realtime collaboration with your peer professionals, located in distributed geographical locations - in our case also involving multiple countries – yet interconnected with audiovisual technology. This empirical study aims to examine how telepresence affects various communication modes at the workplace; teamwork, reflective, leisure activities and so forth. The research team members have identified some key factors that together contribute to a sense of presence, each of them affecting the level of trust and co-existence between two or more parties. Secondly, the report attempts to address the overall notion of communication quality as such; what actually constitutes communication quality in a telepresence context, to what extent is this quality measurable in technical terms, how does the user's perceived sense of quality correlate to measurements, and how does communication quality affect the sense of presence, bonds of trust and feeling of togetherness for members of a virtually co-located, yet geographically separated, working group. This study was carried out by a joint team of researchers at Høgskolen i Lillehammer, Høgskolen i Gjøvik, both in Norway and Kungliga Tekniska Högskolan in Stockholm, Sweden during 2004-2007.

  • Sponberg, Hilding
    et al.
    Dept. of Technology, Gjøvik College, Pb. 191, NO-2802 Gjøvik, Norway.
    Knudsen, Claus
    KTH, School of Computer Science and Communication (CSC), Media Technology and Graphic Arts, Media (closed 20111231).
    Handberg, Leif
    KTH, School of Computer Science and Communication (CSC), Media Technology and Graphic Arts, Media (closed 20111231).
    New learning modes in the production of presence–distance techniques for education.2001Conference paper (Refereed)
    Abstract [en]

    This paper focuses on new learning modes that combine physical and virtual learning spaces and techniques. Synchronous distance technique combined with new dramaturgy and narrative techniques create new learning modes for distance learning. In a series of courses called "Networking Multimedia" students are trained on pedagogical use of video conferencing, integrating several different media tools.The research was based on analysis and evaluation of a large number of video recordings from previous exams and questionnaires among the students. Typical exam projects varied from playing games, give interactive instruction, interactive music performance to virtual marriages, combined ISDN and IP-based videoconferencing and multiple remote control of PCs over the world. During these courses, we have seen that relatively simple techniques can be used for producing programs with a high level of participation and presence – and for the best projects, the technology becomes transparent.

  • Carrizo, Gabriel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Organ Segmentation Using Deep Multi-task Learning with Anatomical Landmarks2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis is the study of multi-task learning to train a neural network to segment medical images and predict anatomical landmarks. The paper shows the results from experiments using medical landmarks in order to attempt to help the network learn the important organ structures quicker. The results found in this study are inconclusive and rather than showing the efficiency of the multi-task framework for learning, they tell a story of the importance of choosing the tasks and dataset wisely. The study also reflects and depicts the general difficulties and pitfalls of performing a project of this type.