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  • Turanli, Beste
    et al.
    KTH.
    Zhang, Cheng
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Kim, Woonghee
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Systems Biology.
    Benfeitas, Rui
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Uhlén, Mathias
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Yalcin Arga, Kazim
    Mardinoglu, Adil
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Discovery of therapeutic agents for prostate cancer using genome-scale metabolic modeling and drug repositioning2019In: EBioMedicine, E-ISSN 2352-3964Article in journal (Refereed)
  • Bidkhori, Gholamreza
    et al.
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Benfeitas, Rui
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Klevstig, Martina
    Zhang, Cheng
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Nielsen, Jens
    Uhlén, Mathias
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Boren, Jan
    Mardinoglu, Adil
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Metabolic network-based stratification of hepatocellular carcinoma reveals three distinct tumor subtypes2018In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490Article in journal (Refereed)
  • Zhang, Cheng
    et al.
    Hua, Qiang
    Applications of Genome-Scale Metabolic Models in Biotechnology and Systems Medicine: Application of GEMs2016In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 6, no January, article id 413Article in journal (Refereed)
    Abstract [en]

    Genome-scale metabolic models (GEMs) have become a popular tool for systems biology, and they have been used in many fields such as industrial biotechnology and systems medicine. Since more and more studies are being conducted using GEMs, they have recently received considerable attention. In this review, we introduce the basic concept of GEMs and provide an overview of their applications in biotechnology, systems medicine, and some other fields. In addition, we describe the general principle of the applications and analyses built on GEMs. The purpose of this review is to introduce the application of GEMs in biological analysis and to promote its wider use by biologists.

  • Misgeld, Olof
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Media Technology and Interaction Design, MID.
    Holzapfel, André
    KTH, School of Electrical Engineering and Computer Science (EECS), Media Technology and Interaction Design, MID.
    Ahlbäck, Sven
    Dancing Dots - Investigating the Link between Dancer and Musician in Swedish Folk Dance2019Conference paper (Refereed)
    Abstract [en]

    The link between musicians and dancers is generally described as strong in many traditional musics and this holds also for Scandinavian Folk Music - spelmansmusik. Understanding the interaction of music and dance has potential for developing theories of performance strategies in artistic practice and for developing interactive systems. In this paper we investigate this link by having Swedish folk musicians perform to animations generated from motion capture recordings of dancers. The different stimuli focus on motions of selected body parts as moving white dots on a computer screen with the aim to understand how different movements can provide reliable cues for musicians. Sound recordings of fiddlers playing to the "dancing dot" were analyzed using automatic alignment to the original music performance related to the dance recordings. Interviews were conducted with musicians and comments were collected in order to shed light on strategies when playing for dancing. Results illustrate a reliable alignment to renderings showing full skeletons of dancers, and an advantage of focused displays of movements in the upper back of the dancer.

  • Mukhopadhyay, Sagnik
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Theoretical Computer Science, TCS. Computer Science Institute of Charles University, Prague, Czech Republic.
    Loff, Bruno
    Lifting Theorems for Equality.2019Conference paper (Refereed)
    Abstract [en]

    We show a deterministic simulation (or lifting) theorem for composed problems f ◦Eqn where the9 inner function (the gadget) is Equality on n bits. When f is a total function on p bits, it is easy to10 show via a rank argument that the communication complexity of f ◦Eqn is Ω(deg(f)·n). However,11 there is a surprising counter-example of a partial function f on p bits, such that any completion f012 of f has deg(f0) = Ω(p), and yet f ◦Eqn has communication complexity O(n). Nonetheless, we are13 able to show that the communication complexity of f ◦Eqn is at least D(f)·n for a complexity14 measure D(f) which is closely related to the AND-query complexity of f and is lower-bounded by15 the logarithm of the leaf complexity of f. As a corollary, we also obtain lifting theorems for the16 set-disjointness gadget, and a lifting theorem in the context of parity decision-trees, for the NOR17 gadget.18 As an application, we prove a tight lower-bound for the deterministic communication complexity19 of the communication problem, where Alice and Bob are each given p-many n-bit strings, with the20 promise that either all of the strings are distinct, or all-but-one of the strings are distinct, and they21 wish to know which is the case. We show that the complexity of this problem is Θ(p·n).

  • Sjöman, Martin
    et al.
    Textilhögskolan vid Högskolan i Borås.
    Svengren Holm, Lisbeth
    Textilhögskolan vid Högskolan i Borås.
    Radón, Anita
    Textilhögskolan vid Högskolan i Borås.
    Entreprenörskap och kreativitet i framgångsrika svenska modeföretag2013In: Kreativt kapital: Om ledning och organisation i kulturella och kreativa näringar / [ed] Emma Senström och Lars Strannegård, Stockholm: 8tto - Volante , 2013, p. 117-155Chapter in book (Other academic)
  • Basmaci, Benjamin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Improving indoor thermal comfort in residential buildings in Andean regions of Peru2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the Peruvian Andes, inadequate housing represents an important problem for the local rural people. Over 3000 meters above sea level, communities suffer from very low indoor temperatures this becomes an issue which affects the health and indoor thermal comfort of the building. At early winter mornings, outdoor temperatures can occasionally go down to -15°C and indoor temperatures can drop below zero. Previous work in the field has been done by the Pontifical Catholic University of Peru PUCP, to address thermal comfort in Langui, Peru involving participatory design techniques, multidisciplinary approaches and a focus on sustainability. Their most recent design is based on an attached passive solar heating system similar to a Trombe wall.

    The effect of housing environment on human health has been an acknowledged issue for many years. In the area, the occupants live with high levels of air infiltration, dirt floor (soil), simple windows, metallic or wood doors, roof most commonly made of corrugated metal sheets, adobe walls, no additional insulation attached and no house heating system. This thesis aims to contribute to a current body of research on thermal comfort and provide insights on how the building environment in Langui can be improved.

    The main objective is to improve thermal comfort in residential buildings in Andean regions of Peru. An improvement was made by installing a Heat Transfer Rocket which increased the temperature while the relative-humidity stayed steady. Overall, the study shows that indoor improvements can increase thermal comfort in Andean regions of Peru.

  • Tuma, Katja
    et al.
    Chalmers | University of Gothenburg.
    Balliu, Musard
    KTH, School of Electrical Engineering and Computer Science (EECS), Theoretical Computer Science, TCS.
    Scandariato, Riccardo
    Chalmers | University of Gothenburg.
    Flaws in Flows: Unveiling Design Flaws via Information Flow Analysis2019Conference paper (Refereed)
  • Sörstedt, Claes
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Cederström, Agneta
    Ruinlandskap byggt på kredit2013In: Arkitektur: byggnad, interiör, plan, landskap, ISSN 0004-2021, no 8, p. 90-97Article in journal (Other (popular science, discussion, etc.))
  • Sörstedt, Claes
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Arrogantly Modest Sweden2006In: A10, ISSN 1573-3815, no 6, p. 54-57Article in journal (Other (popular science, discussion, etc.))
  • Hinders, Johan
    Universitetsbiblioteket, Stockholms universitet.
    Oväntat möte i biblioteket2011In: Kompassriktning: 2000-talet: Festkrift till Catarina Ericsson-Roos / [ed] Eva Enarsson, Leif Friberg, Wilhelm Widmark, Stockholm, 2011, p. 195-204Chapter in book (Other (popular science, discussion, etc.))
  • Hinders, Johan
    Arkeologiska forskningslaboratoriet, Institutionen för arkeologi och antikens kultur, Stockholms universitet.
    Combined Sulfur and Strontium analysis: a model for deeper understanding in mobility for a specific site?: Sulfur analysis on collagen results, compared to strontium analysis on enamel, from Frälsegården passage grave in Falbygden, Sweden.Manuscript (preprint) (Other academic)
    Abstract [en]

    Investigation of human movement in the past has been of great interest in archaeology. Direct measurements of past mobility have become possible through the application of strontium isotope analysis on human skeletal remains; during the last few years, a growing attention has been paid to the stable isotope of sulfur – δ34S. Not until now, there has been no attempt to compare the two methods: strontium analyses – 87Sr/86Sr – on hydroxylapatite, and δ34S- analyses on collagen; in analyzing the very same objects to track mobility patterns. 

       In this paper the outcome and conclusions of two different studies will be compared: one using the strontium isotope method and another on using the sulfur stable isotope method, both investigating material from Falbygden in western Sweden - a cultural and natural landscape with several unique features.

       This study shows that the differences between the two methods might cause different conclusions.

  • Gernandt, Niclas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    Farhod, Jaser
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    JÄMFÖRELSE AV ATTITYDANALYS ALGORITMER FÖR SPELOMDÖMEN2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today there exist a huge amount of user created content in the shape of text from game reviews to opinions in microblogs like Twitter. To analyze this data could be of value for both companies and data scientists but remains to be very daunting. With the help of sentiment analysis this could be achieved automatically and save resources, but the question remains which algorithms have the best performance? With the help of a study and a couple of tests the most popular approaches in sentiment analysis could be compared by analyzing game reviews from the platform Steam. Through testing it has showed that machine learning based algorithms have the best performance and are easier to start with in comparison to lexicon-based approaches, which barely even reach the threshold for reliability in classifying reviews to be positive or negative. But it’s still important to plan and consider which algorithm one chooses for sentiment analysis as both approaches have their flaws and had a weak performance regarding sarcastic reviews.

  • Rixon Fuchs, Louise
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Gällström, Andreas
    Folkesson, John
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Object Recognition in Forward Looking SonarImages using Transfer Learning2018Conference paper (Refereed)
    Abstract [en]

    Forward Looking Sonars (FLS) are a typical choiceof sonar for autonomous underwater vehicles. They are mostoften the main sensor for obstacle avoidance and can be usedfor monitoring, homing, following and docking as well. Thosetasks require discrimination between noise and various classes ofobjects in the sonar images. Robust recognition of sonar data stillremains a problem, but if solved it would enable more autonomyfor underwater vehicles providing more reliable informationabout the surroundings to aid decision making. Recent advancesin image recognition using Deep Learning methods have beenrapid. While image recognition with Deep Learning is known torequire large amounts of labeled data, there are data-efficientlearning methods using generic features learned by a networkpre-trained on data from a different domain. This enables usto work with much smaller domain-specific datasets, makingthe method interesting to explore for sonar object recognitionwith limited amounts of training data. We have developed aConvolutional Neural Network (CNN) based classifier for FLS-images and compared its performance to classification usingclassical methods and hand-crafted features.

  • Torroba, Ignacio
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Bore, Nils
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Folkesson, John
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    A Comparison of Submaps RegistrationMethods for Multibeam Bathymetric Mapping2018Conference paper (Refereed)
    Abstract [en]

    On-the-fly registration of overlapping multi-beam images is important for path planning by AUVs per-forming underwater surveys. In order to meet specificationon such things as survey accuracy, coverage and density,precise corrections to the AUV trajectory while underwayare required. There are fast methods for aligning pointclouds that have been developed for robots. We compareseveral state of the art methods to align point clouds oflarge, unstructured, sub-aquatic areas to build a globalmap. We first collect the multibeam point clouds intosmaller submaps that are then aligned using variationsof the ICP algorithm. This alignment step can be appliedif the error in AUV pose is small. It would be the finalstep in correcting a larger error on loop closing where aplace recognition and a rough alignment would precedeit. In the case of a lawn mower pattern survey it would bemaking more continuous corrections to small errors in theoverlap between parallel lines. In this work we comparedifferent methods for registration in order to determinethe most suitable one for underwater terrain mapping. Todo so, we benchmark the current state of the art solutionsaccording to an error metrics and show the results.

  • Bore, Nils
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Torroba, Ignacio
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Folkesson, John
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Sparse Gaussian Process SLAM, Storage andFiltering for AUV Multibeam Bathymetry2018In: 2018 IEEE OES Autonomous Underwater Vehicle Symposium, 2018Conference paper (Refereed)
    Abstract [en]

    With dead-reckoning from velocity sensors,AUVs may construct short-term, local bathymetry mapsof the sea floor using multibeam sensors. However, theposition estimate from dead-reckoning will include somedrift that grows with time. In this work, we focus on long-term onboard storage of these local bathymetry maps,and the alignment of maps with respect to each other. Wepropose using Sparse Gaussian Processes for this purpose,and show that the representation has several advantages,including an intuitive alignment optimization, data com-pression, and sensor noise filtering. We demonstrate thesethree key capabilities on two real-world datasets.

  • Gunnelin, Åke
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    Netzell, Olof
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics. National Board of Hoursing, Building and Planning.
    The relationship between property transaction prices, turnover rates and buyers' and sellers' reservation price distributionsManuscript (preprint) (Other academic)
    Abstract [en]

    This paper analyzes the relationship between movements in property transaction prices and movements in the underlying reservation price distributions of buyers and sellers and how these movements are linked to time varying turnover rate. A main conclusion in previous research is that transaction prices lag changes in buyers’ reservation price distribution and that an index tracking transaction prices is less volatile than an index tracking buyer reserves. We show that our less restrictive model of search and price formation reverses the volatility result in previous papers in realistic scenarios, i.e., transaction prices may be more volatile than underlying buyer reserves. We model transaction prices and turnover rates as functions of the moments of buyers’ and sellers’ reservation price distributions, the search intensity and the average bargaining power among buyers and sellers respectively. We derive the probability density function of transaction prices as a function of these parameters and hence a Maximum-likelihood estimator of the parameters, which serves as a new method of estimating indexes tracking movements in reservation price distributions from transaction data. We perform simulations where we show that the Maximum-likelihood estimator works as intended.

  • Lundgren, Elin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Evaluating resilience in the governing process of the food strategy for StockholmCounty: Resilience from theory to practice in a qualitativestudy2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To meet global challenges in food provision and to counteract environmental issues derivingfrom the food system, improved governance is necessary. Resilience is presented as a tool formanaging ecosystem services and for understanding what is required to achieve food security.In Sweden there is a national food strategy describing the continued development needed formeeting challenges in the food system. Several regional food strategies have been producedand an additional food strategy for Stockholm County is in the process of being developed byStockholm County Administrative Board. This food strategy could be of especial interest toevaluate due to Stockholm County being highly populated while having a low degree ofprimary food production. Assessing the governance system for the food strategy was ofinterests due to the large groups of stakeholders to consider in the process. The aim of thestudy was to add further knowledge on how resilience can be applied in practice by exploringthe extent of which the governance system for developing the food strategy promotesresilience. The research questions were formulated to investigate the governance system bymapping what stakeholders were involved in the process, what their responsibilities were andwhat relations existed between them. An additional research question was to test how thegovernance system promoted resilience by applying a set of principles for doing so.

    For collecting data, several stakeholders involved in developing the food strategy at the timeof the data collection were interviewed. Complementary data was also collected from journalarticles, books, documents provided by Stockholm County Administrative Board, websites,governmental publications and different kinds of reports. Quotes were selected to explain thefindings from the interviews, and a social network analysis was constructed to illustrate thestructure of the governance system. Another tool in the data analysis, which was also thepoint of the departure for constructing the research questions, was the resilience frameworkconsisting of a set of principles. Among these principles, five where applied for evaluating thegovernance system of the food strategy.

    The results were divided in two parts. The first section presents the results from performinginterviews by describing the governance system; identified stakeholders, their functions aswell as their relations. Two other themes identified from the interviews that were concludedto be important for the resulting governance system and also for the resilience evaluation were“collaboration” and “context”. Several stakeholders were identified, a few were concluded tobe more key than others as they belong to either the management group or the draftingcommittee. The stakeholders had national, regional and local responsibilities and were bothgovernmental and non-governmental organizations. The functions of the stakeholders werefor example to represent a certain part of the food system or contributing with national,regional or local knowledge about the food system. The relations among stakeholders in thegovernance system occurred between stakeholders working within the same geographicalscales and also between national, regional and local scales. In the center of the governancestructure were the management group that are to jointly decide on goals for the final strategydocument.

    The second part of the results constitutes the resilience evaluation, which was accomplishedby testing the results regarding the governance system (from part I) against the framework forresilience using the selected principles. These principles included maintain diversity andredundancy, manage connectivity, encourage learning, broaden participation and promotepolycentric governance. It was concluded that the governance system did follow all of theseprinciples in several aspects, but critical points were also identified. Among the positive 

    aspect were the positive attitude for learning among stakeholders in the governance system,the involvement of heterogenous groups interacting with one another and also themanagement group as a strong centre for decision-making. One of the main critical pointsidentified from performing the resilience evaluation suggests a few stakeholders to be lackingin the present governance system.

    The governance system for the food strategy had a large group of stakeholders, representingdifferent parts of the food system, including national/regional/local and governmental/nongovernmentalorganizations, interacting both within and across geographical scales. Theseaspects are important for promoting resilience according to the principles selected in thisstudy. By adding the suggested stakeholders, for example a few representatives from differentparts of the food system that was not involved in the process at the time of data collection, thegovernance system could promote resilience even more.

  • Public defence: 2019-04-26 10:00 F3, Stockholm
    Bessegato, Luca
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    Modeling of Modular Multilevel Converters for Stability Analysis2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Modular multilevel converters (MMCs) have recently become the state-of-the-art solution for various grid-connected applications, such as high-voltage direct current (HVDC) systems and flexible alternating current transmission systems (FACTS). Modularity, scalability, low power losses, and low harmonic distortion are the outstanding properties that make MMCs a key technology for a sustainable future.

     

    The main objective of this thesis is the modeling of grid-connected MMCs for stability analysis. The stability of the interconnected system, formed by the converter and the ac grid, can be assessed by analyzing the converter ac-side admittance in relation to the grid impedance. Therefore, a method for the calculation of the ac-side admittance of MMCs is developed. This method overcomes the nonlinearities of the converter dynamics and it can be easily adapted to different applications. Moreover, the effects of different control schemes on the MMC ac-side admittance are studied, showing how the converter admittance can be reshaped. This is a useful tool for system design, because it shows how control parameters can be selected to avoid undesired grid-converter interactions.

     

    This thesis also studies ac/ac MMCs for railway power supplies, which are used in countries with a low-frequency railway grid, such as Germany (16.7 Hz) and Sweden (16 2/3 Hz). A hierarchical control scheme for these converters is devised and evaluated, considering the requirements and the operating conditions specific to this application. Furthermore, admittance models of the ac/ac MMC are developed, showing how the suggested hierarchical control scheme affects the three-phase and the single-phase side admittances of the converter. For computing the insertion indices, an open-loop scheme with sum capacitor voltage estimation is applied to the ac/ac MMC. Lyapunov stability theory is used to prove the asymptotic stability of the converter operated with the proposed control method. This specific open-loop scheme is also adapted to a modular multilevel matrix converter, which performs three-to-three phase direct conversion.

     

    Finally, this thesis presents the design of a down-scaled MMC prototype for experimental verification, rated at 10 kW with 30 full-bridge submodules. The hardware and the software are designed to be easily reconfigurable, which makes the converter suitable for different research projects focused on MMCs. Experiments on this down-scaled MMC are used to support and validate the key results presented throughout the thesis.

  • Bijman, Nicolaas Peter
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Exploring affordances of tangible user interfaces for interactive lighting2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper explores interaction with lighting through a tangible user interface (TUI). In a TUI the physical object and space around it are part of the interface. A subset of tangible interaction called spatial interaction is the main focus of this paper. Spatial interaction refers to translation, rotation or location of objects or people within a space. The aim of this paper is to explore the relation between spatial inputs and lighting outputs based on different design properties.

    A user test is set up to explore the effect that design properties of a TUI have on the lighting output that participants map to spatial inputs. The results of the conducted user test indicate that communicating affordances to the user is an important factor when designing couplings between spatial inputs and lighting outputs. The results further show that the shape of the interface plays a central role in communicating those affordances and that the overlap of input and output space of the interface improves the clarity of the coupling.

  • Liljeqvist, Marcus Elwar
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Gaming for Good: Triggering do-good Excitement in a Mobile Game2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Mobile games present a great opportunity for organizations with sustainability agendas to spread their message and generate revenue towards its cause, as they are the best money generating apps. This can be done through designing so-called persuasive games. A major challenge when designing such a game is that the sustainability agenda might compromise the gaming experience, rendering an uninteresting game. The present research explores what could trigger both an interesting game that also compromises a do-good agenda by designing and play testing two versions of a persuasive game called Aqua Escape. Results indicated that users felt more excited about the game once they knew about the social agenda. They also wanted more information on the social agenda integrated into the app than was already there.

  • Yuan, Luyao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Sustainability Aspects of ICT in Agriculture and Food Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis project aims to explore ICT solutions in agriculture and food systems, and to analyze their sustainability aspects. As a result, a comprehensive picture of existing and coming ICT solutions along the food chain is presented based on extensive literature review. Their enabled impacts are qualitatively analyzed for selected aspects of food security and environmental sustainability. Moreover, a few of ICT enabled solutions’ GHG emissions reduction potentials in agricultural and land use sector in the year 2030 are estimated quantitatively, ranging from 9 Mt to 31 Mt, depending on assumptions (6 to 50 Mt after sensitivity analysis). These results, which cannot be seen as a representation of the overall ICT potential to enable emission reductions in agriculture and the food chain, are discussed in light of earlier suggested overall ICT potentials in this area. Moreover, limitations and uncertainties of the study are further clarified. Overall, the qualitative analysis identifies a high number of solutions for ICT in the agriculture and food systems with an assumed potential to promote sustainable development. However, due to the lack of published quality data for these solutions, the predicted sustainability potential cannot be accurately estimated. 

  • Alvarez Custodio, Maria
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Autonomous Recharging System for Drones: Detection and Landing on the Charging Platform2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the last years, the use of indoor drones has increased significantly in many different areas. However, one of the main limitations of the potential of these drones is the battery life. This is due to the fact that the battery size has to be limited since the drones have a maximum payload in order to be able to take-off and maintain the flight. Therefore, a recharging process need to be performed frequently, involving human intervention and thus limiting the drones applications.

    In order to solve this problem, this master thesis presents an autonomous recharging system for a nano drone, the Crazyflie 2.0 by Bitcraze AB. By automating the battery recharging process no human intervention will be needed, and thus overall mission time of the drone can be considerably increased, broadening the possible applications.

    The main goal of this thesis is the design and implementation of a control system for the indoor nano drone, in order to control it towards a landing platform and accurately land on it. The design and implementation of an actual recharging system is carried out too, so that in the end a complete full autonomous system exists.

    Before this controller and system are designed and presented, a research study is first carried out to obtain a background and analyze existing solutions for the autonomous landing problem.

    A camera is integrated together with the Crazyflie 2.0 to detect the landing station and control the drone with respect to this station position. A visual system is designed and implemented for detecting the landing station. For this purpose, a marker from the ArUco library is used to identify the station and estimate the distance to the marker and the camera orientation with respect to it.

    Finally, some tests are carried out to evaluate the system. The flight time obtained is 4.6 minutes and the landing performance (the rate of correct landings) is 80%.

  • Harren, Maja
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Application of Circular Economy to SME Batik Dyeing and Finishing: Sustainability Vetting of Ciwaringin Batik2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study is part of a feasibility study conducted by the Sustainability and Resilience Company (su-re.co), and is identified within this report as the sustainability vetting. This study aims to evaluate the sustainability of the natural indigo-dyeing process at a small medium enterprise (SME) batik dying community, Ciwaringin Batik, located in Cirebon, West Java, Indonesia. Following this, sustainable development strategies (SDS) based on the Circular Economy (CE) RESOLVE Framework will be created for Ciwaringin Batik to further empower the community and provide sustainable business growth initiatives. An iterative qualitative and quantitative data methodology is used when collecting and analyzing production data from Ciwaringin Batik. Data is collected from 9 Ciwaringin Batik craftsmen, who use natural indigo dye during batik production, in Life Cycle Inventory (LCI) format, questionnaires, and through a site-visit to Ciwaringin Batik. Water and indigo consumption data was thoroughly analyzed as it is directly related to a feasibility study conducted by su-re.co and is relevant to their future involvement with Ciwaringin. Current sustainable and “unsustainable” production practices were identified, 10 SDS’s were created following the RESOLVE framework structure, 6 SDS’s were explained and then prioritized regarding implementation feasibility.

  • Public defence: 2019-04-26 10:00 Kollegiesalen, Stockholm
    Zandi Shafagh, Reza
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Thiol-ene Nanostructuring2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Improving the health and well-being of humankind does not only constitute

    part of our moral codes, but is also enlisted as the number three goal of

    the 2030 agenda for sustainable development set by the UN. Fulfilling such

    objective in the regions of resource-poor settings or for age groups with more

    vulnerability to infectious agents demands immediate actions. This has necessitated

    novel ways of rapid and ultra-sensitive diagnostics to provide compact

    and affordable systems, e.g. for an early detection of bacteria and viruses.

    The fields of bio-micro/nanoelectromechanical systems (BioMEMS/NEMS)

    and lab-on-a-chip (LoC) have been founded based on such demands, but

    critically challenged by problems partly associated with manufacturing and

    material domains and biosensing methods. The fabrication methods for the

    miniaturization of features and components are often complicated and expensive,

    the commonly used materials are typically not adaptable to industrial

    settings, and the sensing mechanisms are sometimes not sensitive enough for

    the detection of lowly-concentrated samples.

    In this thesis, new methods of ultra-miniaturization, as well as conventional

    cleanroom-based techniques, for nanopatterning of well-defined topographies

    in off-stoichiometry thiol-ene-(epoxy) polymers are presented. In addition,

    their use for several sensing applications has been demonstrated. The

    first part of the thesis gives an introduction to the field of BioMEMS/NEMS.

    The second part of the thesis presents a technical background about the

    prevalent methods of polymer micro- and nanofabrication, implementation

    of the resulting polymer structures for different sensing applications, along

    with the existing challenges and shortcomings associated with state of the

    art. The third part of the thesis presents e-beam nanostructuring of thiol-ene

    resist, for the first time, achieving the smallest and densest features reported

    in these polymer networks. The thiol-ene-based polymer also represents a

    novel class of e-beam resist resulting in structures with reactive surface nature.

    The fourth part of the thesis demonstrates the use of thiol-ene-epoxy

    systems for nanoimprint lithography and further shows the structuring of

    high-aspect-ratio and hierarchical topologies via single-step UV-NIL. The fifth

    part of the thesis introduces Micro- and NanoRIM platforms for scalable and

    off-cleanroom manufacturing of microfluidic devices and nanostructuring of

    materials in thiol-ene (-epoxy) systems. The sixth part of the thesis exhibits

    the implementation of the noted nanofabrication methods for different

    BioMEMS/NEMS applications including protein nanopatterning, simultaneous

    molding and surface energy patterning, ultra-sensitive digital biosensing,

    and facile quartz crystal microbalance (QCM) sensor packaging.

  • Public defence: 2019-04-26 18:22 FA32, Stockholm
    Bergstrand, Jan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Super resolution fluorescence imaging: analyses, simulations and applications2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fluorescence methods offer extraordinary sensitivity and specificity, and are extensively used in the life sciences. In recent years, super resolution fluorescence imaging techniques have developed strongly, uniquely combining ~10 nm sub diffraction resolution and specific labeling with high efficiency. This thesis explores this potential, with a major focus on Stimulated Emission Depletion, STED, microscopy, applications thereof, image analyses and simulation studies. An additional theme in this thesis is development and use of single molecule fluorescence correlation spectroscopy, FCS, and related techniques, as tools to study dynamic processes at the molecular level. In paper I the proteins cytochrome-bo3 and ATP-synthase are studied with fluorescence cross-correlation spectroscopy, FCCS. These two proteins are a part of the energy conversion process in E. coli, converting ADP into ATP. We found that an increased interaction between these proteins, detected by FCCS, correlates with an increase in the ATP production. In paper II an FCS-based imaging method is developed, capable to determine absolute sizes of objects, smaller than the resolution limit of the microscope used. Combined with STED, this may open for studies of membrane nano-domains, such as those investigated by simulations in paper VII. In paper III and paper IV super resolution STED imaging was applied on Streptococcus Pneumoniae, revealing information about function and distribution of proteins involved in the defense mechanism of the bacteria, as well as their role in bacterial meningitis. In paper V, we used STED imaging to investigate protein distributions in platelets. We then found that the adhesion protein P-selectin changes its distribution pattern in platelets incubated with tumor cells, and with machine learning algorithms and classical image analysis of the STED images it is possible to automatically distinguish such platelets from platelets activated by other means. This could provide a strategy for minimally invasive diagnostics of early cancer development, and deeper understanding of the role of platelets in cancer development. Finally, this thesis presents Monte-Carlo simulations of biological processes and their monitoring by FCS. In paper VI, a combination of FCCS and simulations was applied to resolve the interactions between a transcription factor (p53) and an oncoprotein (MDM2) inside live cells. In paper VII, the feasibility of FCS techniques for studying nano-domains in membranes is investigated purely by simulations, identifying the conditions under which such nano-domains would be possible to detect by FCS. In paper VIII, proton exchange dynamics at biological membranes were simulated in a model, verifying experimental FCS data and identifying fundamental mechanisms by which membranes mediate proton exchange on a local (~10nm) scale.

  • Bafounis Kottas, Emmanouil
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Implementation and integration of a collaborative robot in a production line2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Scope of this thesis is the integration and implementation of a collaborative robot in the production line. In the first chapter, the project is described, and its objectives, purpose, boundaries and requirements are defined. Moreover, the project management tools and techniques are presented. All the steps and procedures followed before the initiation of the project are analysed. In the second chapter, the basic theoretical background necessary for a better understanding of the content of this thesis is presented. The history and development of collaborative robots, as well as the industrial evolutions are mentioned. The different types of collaborative robots and their importance in Industry 4.0 and current production are analysed. The third chapter deals with the detailed description of the project. All the devices and equipment are presented thoroughly. The programming logic and working flow is explained. In the last chapter according to the initial objectives, boundaries and requirements the success of the project is assessed. An analysis of how the installation of automate corrugate loader affected the production process is performed. Future changes, improvements and technical suggestions are discussed. The ultimate goal of this thesis project is that the content in the thesis report will be used as a guide for future installations of same or similar type of robots. The aim is to avoid many of the mistakes made, due to rush decisions, lack of experience and communication between team members. The leaning curve obtained during the implementation of the project, can lead to more effective projects in the future.

  • Bergstrand, Jan
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Xu, Lei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Miao, Xinyan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Li, Nailin
    Karolinska Institutet, Department of Medicine, Karolinska University Hospital, L7:03, SE-171 76 Stockholm, Sweden.
    Öktem, Ozan
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematics (Div.).
    Franzén, Bo
    Karolinska Institutet, Department of Medicine, Karolinska University Hospital, L7:03, SE-171 76 Stockholm, Sweden.
    Auer, Gert
    Karolinska Institutet, Department of Medicine, Karolinska University Hospital, L7:03, SE-171 76 Stockholm, Sweden.
    Lomnytska, Marta
    Karolinska Institutet, Department of Medicine, Karolinska University Hospital, L7:03, SE-171 76 Stockholm, Sweden.
    Widengren, Jerker
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Super-resolution microscopy can identify specific protein distribution patterns in platelets incubated with cancer cellsManuscript (preprint) (Other academic)
    Abstract [en]

    Protein contents in platelets are frequently changed upon tumor development and metastasis. However, how cancer cells can influence protein-selective redistribution and release within platelets, thereby promoting tumor development, remains largely elusive. With fluorescence-based super-resolution stimulated emission depletion (STED) imaging we reveal how specific proteins, implicated in tumor progression and metastasis, re-distribute within platelets, when subject to soluble activators (thrombin, adenosine-diphosphate and thromboxaneA2), and when incubated with cancer (MCF-7, MDA-MB-231, EFO21) or non-cancer cells (184A1, MCF10A). Upon cancer cell incubation, the cell-adhesion protein P-selectin was found to re-distribute into circular nano-structures, consistent with accumulation into the membrane of protein-storing alpha-granules within the platelets. These changes were to a significantly lesser extent, if at all, found in platelets incubated with normal cells, or in platelets subject to soluble platelet activators. From these patterns, we developed a classification procedure, whereby platelets exposed to cancer cells, to non-cancer cells, soluble activators as well as non-activated platelets all could be identified in an automatic, objective manner. We demonstrate that STED imaging, in contrast to electron and confocal microscopy, has the necessary spatial resolution and labelling efficiency to identify protein distribution patterns in platelets and can resolve how they specifically change upon different activations. Combined with image analyses of specific protein distribution patterns within the platelets, STED imaging can thus have a role in future platelet-based cancer diagnostics and therapeutic monitoring. The presented approach can also bring further clarity into fundamental mechanisms for cancer cell-platelet interactions, and into non-contact cell-to-cell interactions in general. 

  • Mohanan, Ashwin Vishnu
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics.
    Bonamy, Cyrille
    LEGI, Université Grenoble Alpes.
    Augier, Pierre
    LEGI, Université Grenoble Alpes.
    FluidFFT: Common API (C++ and Python) for Fast Fourier Transform HPC Libraries2019In: Journal of Open Research Software, E-ISSN 2049-9647, Vol. 7, no 1Article in journal (Refereed)
    Abstract [en]

    The Python package fluidfft provides a common Python API for performing Fast Fourier Transforms (FFT) in sequential, in parallel and on GPU with different FFT libraries (FFTW, P3DFFT, PFFT, cuFFT). fluidfft is a comprehensive FFT framework which allows Python users to easily and efficiently perform FFT and the associated tasks, such as computing linear operators and energy spectra. We describe the architecture of the package composed of C++ and Cython FFT classes, Python “operator” classes and Pythran functions. The package supplies utilities to easily test itself and benchmark the different FFT solutions for a particular case and on a particular machine. We present a performance scaling analysis on three different computing clusters and a microbenchmark showing that fluidfft is an interesting solution to write efficient Python applications using FFT. 

  • Augier, Pierre
    et al.
    LEGI, Université Grenoble Alpes.
    Mohanan, Ashwin Vishnu
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Bonamy, Cyrille
    LEGI, Université Grenoble Alpes.
    FluidDyn: A Python Open-Source Framework for Research and Teaching in Fluid Dynamics by Simulations, Experiments and Data Processing2019In: Journal of Open Research Software, E-ISSN ‎2049-9647, Vol. 7, no 1Article in journal (Refereed)
    Abstract [en]

    FluidDyn is a project to foster open-science and open-source in the fluid dynamics community. It is thought of as a research project to channel open-source dynamics, methods and tools to do science. We propose a set of Python packages forming a framework to study fluid dynamics with different methods, in particular laboratory experiments (package fluidlab), simulations (packages fluidfft, fluidsim and fluidfoam) and data processing (package fluidimage). In the present article, we give an overview of the specialized packages of the project and then focus on the base package called fluiddyn, which contains common code used in the specialized packages. Packages fluidfft and fluidsim are described with greater detail in two companion papers [4, 5]. With the project FluidDyn, we demonstrate that specialized scientific code can be written with methods and good practices of the open-source community. The Mercurial repositories are available in Bitbucket (https://bitbucket.org/fluiddyn/). All codes are documented using Sphinx and Read the Docs, and tested with continuous integration run on Bitbucket Pipelines and Travis. To improve the reuse potential, the codes are as modular as possible, leveraging the simple object-oriented programming model of Python. All codes are also written to be highly efficient, using C++, Cython and Pythran to speedup the performance of critical functions.

  • CASSEL, JULIA
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Product and Service Design.
    ÖSTEVIK, AGNES
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Product and Service Design.
    Translucent concrete in product design: Implementation of a new segment of design products through Strategic branding2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The company Butong is based on a patented process of casting concrete between two layers of bubble wrap, resulting in panels of translucent concrete. This material is mainly applied as panels in vertical gardens and light installations. Today, the business is based on projects that require custom made designs. Alongside these projects, products with a standardised manufacturing process are desired to extend the company towards the consumer market and fill the workflow gaps existing in their current production. Through strategic branding, this project aimed to create a new business segment of standardised design products and the framework needed for Butong to enter the consumer market. From analysing the company and its values, understanding the possibilities and limitations of the material and from investigating the opportunities on the market, the brand position for the segment was determined. A strategy to establish the business on the targeted market was developed, including a brand identity and design guidelines for the new segment. To exemplify the usage of the guidelines, several concepts were produced, of which one was further developed to be the flagship product of the segment. The segment was directed to target both Butong’s current market and the consumer market in order to facilitate its establishment and to reach a larger public. It is developed to consist of products that clearly display the properties of the material and are aligned to the identity of the brand. Following the set guidelines, the developed concepts confirm its value and potential by communicating coherency and the expressions desired. With a standardised manufacturing process, the production can be engaged at any time to make use of the existing workflow gaps and complement Butong’s existing business without obstructing it.

  • Eklund, Agnes
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Correlations related to fuel usage patterns in rural Kenya: A comparison of local surveys to facilitate future local sustainable fuel actions.2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Human activities affect the climate. If the utilization of fossil and other hazardous fuel methods is eliminated, it would reduce the impact on climate change. By investigating fuel usage patterns in three rural areas of Kenya, looking at social, economic and ecological factors, a foundation to facilitate future local actions towards sustainable fuel consumption can be made. With the help of local surveys performed in Siaya, Kwale and Embu, correlations could be found. The data was not extensive enough to generate general conclusions but can act as a beginning to a foundation for future sustainable actions. More data should be retrieved and investigated regarding methods and local conditions included in this project to work as a well-rounded foundation for future local actions regarding fuel methods and practices.

  • Byström, Emma
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Kartläggning av kylkompressorer: Baserad på katalogdata från kompressortillverkare2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis aims to chart the behaviour of modern compressors, using low GWP (global warming potential) refrigerants during different operating conditions. The aim is also to present the gathered data in form of diagrams and tables. The isentropic and volumetric efficiencies are the main parameters that have been used to chart the behaviour of the compressors in this project.

    In some cases, it has not been possible to calculate the isentropic efficiency regarding the semihermetic and hermetic compressor models that occur in this report. In these cases, the overall efficiency for a hermetic or a semi-hermetic compressor has been used instead. The overall efficiency is based on the total electric power input to the compressor unit.

    In order to chart the behaviour, three refrigerants were chosen in combination with different compressor models. The chosen refrigerants were carbon dioxide (R744), propane (R290) and tetrafluorethane (R134a), and the compressor models were of the types piston and scroll. The compressors models, in combination with the refrigerants, were chosen from the software tools Select 8 and Coolselector 2 provided by the manufacturers Emerson and Danfoss. The input variables consisted of two values for superheat and several values for condensing and evaporatingtemperatures. The compressor models used in this report are either hermetic or semi-hermetic. Some of the desired data was not available in the software and had to be calculated using well known equations regarding the vapor compression cycle with superheated suction vapor. Finally, both the collected and calculated data was compiled into tables and diagrams. The final shape of the diagrams was inspired by previous work available through mentioned course literature.

    It is still unclear if what is labelled as “isentropic efficiency” for hermetic and semi-hermetic compressors in Select 8 truly considers only the mechanical losses during the compression, or if it takes into account all losses in the compressor unit. If the latter, the efficiency should be considered as an overall efficiency for a hermetic or semi-hermetic compressor, not isentropic.

    The intention in this report has been to separate the isentropic efficiency from the overall efficiency regarding hermetic compressors, since these are two distinct efficiencies according to the course literature used. However, when an efficiency has been reported as “isentropic” by the manufacturer, it has also been labelled as so in the report. Therefore, if the efficiency is mislabelled in the software, it is also mislabelled in this report. A word of caution is therefore advised when taking part of these results, with regards to the isentropic efficiency whenever mentioned.

    Except for the confusion surrounding the meaning of isentropic efficiency in Select 8, the purpose and objectives of this bachelor thesis have been fulfilled.

  • Zhu, Yi
    KTH, School of Architecture and the Built Environment (ABE).
    Extracting masts of overhead supply and street lights from point cloud2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Regular inspection and documentation for railway assets are necessary to monitor the status of the traffic environment. Mobile Laser Scanning (MLS) makes it possible to collect highly accurate spatial information of railway environments in the form of point cloud, and an automatic method to extract interested objects from the point cloud is needed to avoid too much manual work.

    In this project, point cloud along a railway in Saltsjöbanan was collected by MLS and processed to extract interested objects from it. The main purpose of the project is to develop a workflow for automatic extraction of masts of overhead supply and street lights from the study area.

    Researchers have proposed various methods for object extraction, such as model-based method, shape-based method, semantic method, and machine learning method recently. Different methods were reviewed and Support Vector Machine was chosen for the classification. Several softwares were reviewed as well. TerraScan and CloudCompare were chosen for pre-processing, and the major part was done in MATLAB.

    The proposed method consists of 4 steps: pre-processing, voxelization and segmentation, feature computation, classification and validation. The method calculates features to describe every object segmented from the point cloud and learns from the manually classified objects to train a classifier.

    The study area was divided into training data and validating data. The SVM classifier was trained using training data and evaluated using validating data.

    In the classification, 90.84% of the masts and 67.65% of the lights were correctly classified. There was some object loss during the step of pre-processing and segmentation. When including the loss from the pre-processing and segmentation step, 87.5% of the masts and 53.49% of the lights were successfully detected. The street lights have more various outlook and more complicated surrounding environment, which caused a relatively low accuracy.

  • Kaijser, Arne
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    Sweden and Chernobyl: Disclosing the disaster, receiving much fallout, but not changing energy policy2016Conference paper (Other academic)
  • Kaijser, Arne
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    The rise and fall of anti-nuclear movements: The case of Sweden2016Conference paper (Other academic)
  • Kaijser, Arne
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    Sweden Short Country Report: Report for the HoNEST project2017Report (Refereed)
  • Ahlsén, David
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Experimental and numerical fluid-structure interaction analysis of a suspended rod subjected to forced vibrations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study is evaluating Solid-Acoustic Finite Element modelling as a method for calculating structural vibration response in water. When designing for example vehicles, it is important to avoid vibrational resonance in any part of the structure, as this causes additional noise and reduced lifespan. It is known that vibration response can be affected by the surrounding medium, i.e. water for marine applications.Previous studies show that this effect is both material and geometry dependant why it is hard to apply standardised design rules. An alternative approach is direct calculation using full Fluid Structure Interaction (FSI) by Computational Fluid Dynamics (CFD) and Finite Element Methods (FEM) which is a powerful but slow and computationally costly method.Therefore, there exists a need for a faster and more efficient calculation method to predict how structures subjected to dynamic loads will respond when submerged in water. By modelling water as an acoustic medium, viscous effects are neglected and calculation time can be drastically reduced. Such an approximation is a linearization of the problem and can be suitable when all deformations are assumed to be small and there are no other nonlinear effects present.This study consists of experimental tests where vibrational response was measured for rod shaped test specimens which were suspended in a water filled test rig and excited using an electrodynamic shaker. A Solid-Acoustic Finite Element model of the same experiment was created, and the test and simulation results were compared. The numerical results were shown to agree well with experiments up to 450 Hz. Above 450 Hz differences occur which is probably due to a simplified rig geometry in the numerical model.

  • Zhang, Kewei
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Papadimitratos, Panagiotis
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Secure Multi-constellation GNSS Receivers with Clustering-based Solution Separation Algorithm2019In: Proceedings of the IEEE Aerospace Conference 2019, 2019Conference paper (Refereed)
    Abstract [en]

    Because of the limited satellite visibility, reduced sig-nal reception reliability and constraining spatial geometry, e.g.,in urban areas, the development of multi-constellation globalnavigation satellite systems (GNSS) has gained traction rapidly.GNSS-based applications are expected to handle observationsfrom different navigation systems, e.g., GPS, GLONASS, Bei-Dou and Galileo, in order to improve positioning accuracy andreliability. Furthermore, multi-constellation receivers presentan opportunity to better counter spoofing and replaying attacks,leveraging approaches take advantage of the redundant mea-surements. In particular, cluster-based solution separation al-gorithm (CSSA) proposes to detect and identify faulty/malicioussignals in a single GPS constellation by checking the consistencyof receiver positions calculated with different number of satel-lites. Intuitively, the algorithm targets directly the consequenceof spoofing/replaying attacks: the victim receiver position errorestimation. It works independently of how the attacks arelaunched, either through modifying pseudorange measurementsor manipulating the navigation messages, without changing thereceiver hardware. Multi-constellation GNSS receivers utilizeall observations from different navigation systems, there aremore than 30 available satellites at each epoch after Galileo andBeiDou systems become fully operational; in other words usingabundant redundancy. Therefore, we introduce such a CSSAto a multi-constellation receiver. The work shows that a multi-constellation GNSS receiver equipped with our algorithm workseffectively against a strong spoofing/replaying attacker that canmanipulate a large number of signals, or even an entire constel-lation. The results show that CSSA with multi-constellation sig-nificantly improves the performance of detecting and identifyingthe malicious signals; particularly, when the adversary cannotcontrol all the constellations, a multi-constellation receiver canidentify the faults even the adversary induces very small errorsto pseudorange measurements, comparing with a single con-stellation receiver. Moreover, when the attacker is powerfulto manipulate most of signals of all the constellations, a multi-constellation receiver with CSSA can still detect and identify thefaulty signals with high probability when the attacker tries tomislead the victim more than a couple of hundred meters fromits true location.

  • Zhang, Kewei
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Papadimitratos, Panagiotis
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    On the Effects of Distance-decreasing Attacks on Cryptographically Protected GNSS Signals2019In: Proceedings of the 2019 International Technical Meeting of The Institute of Navigation, 2019, p. 363-372Conference paper (Refereed)
    Abstract [en]

    The security of global navigation satellite systems draws attention increasingly, and authentication mechanisms for civilian services seem very effective in thwarting malicious behavior. For example, the Galileo E1 Open Service introduces navigation message authentication. Authentication, as well as encryption at navigation message or spreading code level, can prevent spoofing attacks, but do not preclude replay attacks. In this work, we consider a type of strong replay attacks, distance-decreasing attacks, against cryptographically protected GNSS signals. Distance-decreasing attack enhance an attacker’s capability of allowing it to mislead the victim receiver that the GNSS signals arrive earlier than true signals. We analyze the instantiation and the effects of the distance-decreasing attacks on unprotected GNSS signals, on navigation message authenticated signals, and on spreading-code encrypted signals. We discuss different strategies that the attacker can adopt to introduce the least bit errors to the re-transmitted signals and avoid being detected at the victim receiver. We provide evaluation results of distance-decreasing attacks on unprotected signals and authenticated navigation message signals, based on different strategies and configurations, and we sketch countermeasures to the different strategies.

  • Public defence: 2019-04-25 13:00 B3, Stockholm
    Ríos Bayona, Francisco
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Analytical and numerical approaches to estimate peak shear strength of rock joints2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In Sweden, there exists a large number of dams. Many of them are founded on rock masses normally affected by the presence of sub-horizontal rock fractures, which makes sliding along rock joints under the dam foundation one of the most critical failure mechanism. Various attempts have been made to relate the peak shear strength of rock joints to measurable parameters. However, the uncertainty in the determination of the shear strength of rock joints is nonetheless still significant.The main aim of this thesis is to investigate, develop and apply analytical and numerical techniques for estimation of peak shear strength of natural and unfilled rock joints. In a first step, the peak shear strength of several natural and unfilled rock joint was calculated by using surface aperture measurements from high-resolution optical scanning and a modified version of the analytical criterion previously developed by Johansson and Stille in 2014. In a second step, PFC2D was utilised to perform numerical shear tests on two-dimensional profiles selected from high-resolution optical scanning on unweathered and perfectly mated tensile induced rock joints.The results from the analytical approach show that the calculated peak shear strengths of the analysed samples are in good agreement compared with the laboratory investigations. Conversely, the obtained results from the numerical approach show lower peak shear strengths in the analysed two-dimensional profiles compared with the conducted laboratory shear tests.The analytical approach together with the advanced techniques to measure surface roughness available today, may be a possible way forward towards a methodology to determine peak shear strength of large-scale natural rock joints in-situ.

  • Bondarenko, Artem
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Nonlinear dynamics of strongly-bound magnetic vortex pairs2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This work is a study of nonlinear phenomena in vertically stacked pairs of magnetic vortices. New dynamic regimes are uncovered with a decrease in the inter-vortex separation to below the lateral vortex-core size. These include linear, non-linear, and chaos dynamics of the coupled vortex cores, as well as core-core coupling/decoupling driven by resonant microwave fields. In addition to the direct advantages gained from the favorable symmetry of the system, which includes the fringing flux closure, new ways of exciting and controlling the motion of the vortex cores are shown. The dynamics of the vortex stack show promising improvements over those of a single vortex, in particular the characteristic speed of operation can be increased by an order of magnitude. The system therefore is viewed to have the potential for applications in data storage and oscillators.

    A combination of experimental, analytical, and numerical methods is used. A theoretical framework based on the quasiparticle Thiele-equation approach, extended to thermally driven dynamics by using the Monte Carlo method, is constructed and extensively tested experimentally and numerically. In-depth micromagnetic simulations are performed and show consistency with the results obtained analytically, both successfully validated against the measured data collected in a series of experiments on spin vortex pairs. Among these are microwave spectroscopy, transient dynamics, thermal decay, and pinning spectroscopy measurements.

    In particular, it is shown that the nonlinear frequency response of a two-vortex system exhibits a fold-over and an isolated rotational core-core resonance. A parametric inter-modal interaction is shown to induce hybrid dynamic regimes of the vortex-core oscillation when the system is subject to high excitation amplitudes.

    An intrinsic bi-stability of the core positions in the structure is found and investigated as a candidate for a memory element. The bi-stability is pronounced at lower temperatures. The rates of thermal switching were investigated in order to find the optimum operating DC-bias conditions.

    It is found that parametric interactions play a big role in the otherwise frustrated dynamics of essentially a 1D system. The parameters of the short excitation pulses for switching between the core-core states are optimized to achieve switching probabilities of over 90% in the experiment, with the pulses only a few nanoseconds long.

    Vortex pairs are demonstrated to be sensitive to the presence of defects in the ferromagnetic layers of the nanostructure. It is shown that the key factor in this sensitivity lies in the vortex' flux closure. Binding of a core-core pair to a defect is observed experimentally. A model is developed to describe the changes in the dynamical characteristics of the defect-pinned vortex pair. The capabilities of the model for characterizing magnetic and morphological defects in nanostructures are demonstrated.

  • Alcocer Bonifaz, Joaquin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Design of High Performance Flanges and its Influence on Manufacturing Costs, Structural Performance and Weight2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project attempts to research the manufacturing cost, with an emphasis on machining, of high performance flanges for Turbine Rear Structure (TRS) applications, as well as the tradeoffs with structural performance and weight. A combination of traditional cost modelling techniques from the literature, as well as, the non-conventional manufacturing complexity index, as cost indicator are implemented. A multidisciplinary study is carried out with the aid of ANSYS Workbench in the form of computer simulated experiments to investigate tradeoffs in flanges. It is concluded that multidisciplinary studies of cost, performance and weight lacked model robustness to draw sound conclusions about flange design. However, the manufacturing complexity index after partial validation with experienced engineers shows promising results, and could be a way forward to estimate final machining operation cost for flanges in the future.

  • Public defence: 2019-04-26 13:30 Kollegiesalen, Stockholm
    Cao, Le Phuong
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Optimal Transmit Strategies for Multi-antenna Systems with Joint Sum and Per-antenna Power Constraints2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nowadays, wireless communications have become an essential part of our daily life. During the last decade, both the number of users and their demands for wireless data have tremendously increased. Multi-antenna communication is a promising solution to meet this ever-growing traffic demands. In this dissertation, we study the optimal transmit strategies for multi-antenna systems with advanced power constraints, in particular joint sum and per-antenna power constraints. We focus on three different models including multi-antenna point-to-point channels, wiretap channels and massive multiple-input multiple-output (MIMO) setups. The solutions are provided either in closed-form or efficient iterative algorithms, which are ready to be implemented in practical systems.

    The first part is concerned with the optimal transmit strategies for point-to-point multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) channels with joint sum and per-antenna power constraints. For the Gaussian MISO channels, a closed-form characterization of an optimal beamforming strategy is derived. It is shown that we can always find an optimal beamforming transmit strategy that allocates the maximal sum power with phases matched to the complex channel coefficients. An interesting property of the optimal power allocation is that whenever the optimal power allocation of the corresponding problem with sum power constraint only exceeds per-antenna power constraints, it is optimal to allocate maximal per-antenna power to those antennas to satisfy the per-antenna power constraints. The remaining power is distributed among the other antennas whose optimal allocation follows from a reduced joint sum and per-antenna power constraints problem with fewer channel coefficients and a reduced sum power constraint. For the Gaussian MIMO channels, it is shown that if an unconstraint optimal power allocation for an antenna exceeds a per-antenna power constraint, then the maximal power for this antenna is used in the constraint optimal transmit strategy. This observation is then used in an iterative algorithm to compute the optimal transmit strategy in closed-form.

    In the second part of the thesis, we investigate the optimal transmit strategies for Gaussian MISO wiretap channels. Motivated by the fact that the non-secure capacity of the MISO wiretap channels is usually larger than the secrecy capacity, we study the optimal trade-off between those two rates with different power constraint settings, in particular, sum power constraint only, per-antenna power constraints only, and joint sum and per-antenna power constraints. To characterize the boundary of the optimal rate region, which describes the optimal trade-off between non-secure transmission and secrecy rates, related problems to find optimal transmit strategies that maximize the weighted rate sum with different power constraints are derived. Since these problems are not necessarily convex, equivalent problem formulation is used to derive optimal transmit strategies. A closed-formsolution is provided for sum power constraint only problem. Under per-antenna power constraints, necessary conditions to find the optimal power allocation are provided. Sufficient conditions, however, are available for the case of two transmit antennas only. For the special case of parallel channels, the optimal transmit strategies can deduced from an equivalent point-to-point channel problem. In this case, there is no trade-off between secrecy and non-secrecy rate, i.e., there is onlya transmit strategy that maximizes both rates.

    Finally, the optimal transmit strategies for large-scale MISO and massive MIMO systems with sub-connected hybrid analog-digital beamforming architecture, RF chain and per-antenna power constraints are studied. The system is configured such that each RF chain serves a group of antennas. For the large-scale MISO system, necessary and sufficient conditions to design the optimal digital and analog precoders are provided. It is optimal that the phase at each antenna is matched tothe channel so that we have constructive alignment. Unfortunately, for the massive MIMO system, only necessary conditions are provided. The necessary conditions to design the digital precoder are established based on a generalized water-filling and joint sum and per-antenna optimal power allocation solution, while the analog precoder is based on a per-antenna power allocation solution only. Further, we provide the optimal power allocation for sub-connected setups based on two properties: (i) Each RF chain uses full power and (ii) if the optimal power allocation of the unconstraint problem violates a per-antenna power constraint then it is optimal to allocate the maximal power for that antenna. The results in the dissertation demonstrate that future wireless networks can achieved higher data rates with less power consumption. The designs of optimal transmit strategies provided in this dissertation are valuable for ongoing implementations in future wireless networks. The insights offered through the analysis and design of the optimal transmit strategies in the dissertation also provide the understanding of the optimal power allocation on practical multi-antenna systems.

  • Varava, Anastasiia
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
    Path-Connectivity of the Free Space: Caging and Path Existence2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The notion of configuration space is a tool that allows to reason aboutan object’s mobility in a unified manner. The problem of verifying path non-existence can be considered as dual to path planning. The question here iswhether a body (a robot, a vehicle, or an object) can move between start andgoal configurations without colliding with obstacles. Caging is a notion fromrobotic manipulation that can be seen as a special case of this problem: anobject is caged when it cannot escape arbitrarily far from its initial position.In this thesis, we address the problems of caging and path non-existence indifferent settings. Firstly, we design a theoretical framework and verificationalgorithms for caging of three-dimensional partially-deformable objects withspecific global geometric features that can be described as narrow parts. Sec-ondly, we formulate and address the problem of herding by caging: given agroup of moving agents and a team of mobile robots, the task is to guide theagents to a predefined goal region without letting them escape at any mo-ment of time. Thirdly, we propose an algorithm for efficient approximationof three- and six-dimensional configuration spaces of arbitrary rigid objects.This approximation can be later used to identify caging configurations as wellas to verify path existence between given configurations. Finally, we reportour preliminary results on molecular caging screening. This project buildsupon our previous work on configuration space approximation.

  • Säger, Florian
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    A Feasibility Study of an Automated Repair Process using Laser Metal Deposition (LMD) with a Machine Integrated Component Measuring Solutio2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The repair of worn or damaged components is becoming more attractive to manufacturers, since it enables them to save resources, like raw material and energy. With that costs can be reduced, and profit can be maximised. When enabling the re-use of components, the lifetime of a component can be extended, which leads to improved sustainability measures. However, repair is not applied widely, mainly because costs of repairing are overreaching the costs of purchasing a new component. One of the biggest expense factors of repairing a metal component is the labourintense part of identifying and quantifying worn or damages areas with the use of various external measurement systems. An automated measuring process would reduce application cost significantly and allow the applications to less cost intense component. To automate the repair process, in a one-machine solution, it is prerequisite that a measuring device is included in the machine enclosure. For that, different measuring solutions are being assessed towards applicability on the “Trumpf TruLaser Cell 3000 Series”. A machine that uses the Laser Metal Deposition (LMD) technology to print, respectively weld, metal on a target surface. After a theoretical analysis of different solutions, the most sufficient solution is being validated by applying to the machine. During the validation a surface models from a test-component is generated. The result is used to determine the capability of detecting worn areas by doing an automated target-actual comparison with a specialised CAM program. By verifying the capability of detecting worn areas and executing a successful repair, the fundamentals of a fully automated repair process can be proven as possible in a one-machine solution.

  • Johansson, Tobias
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Managed Distributed TensorFlow with YARN: Enabling Large-Scale Machine Learning on Hadoop Clusters2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Apache Hadoop is the dominant open source platform for the storage and processing of Big Data. With the data stored in Hadoop clusters, it is advantageous to be able to run TensorFlow applications on the same cluster that holds the input data sets for training machine learning models. TensorFlow supports distributed executions where Deep Neural Networks can be trained utilizing a large amount of compute nodes. To configure and launch distributed TensorFlow applications manually is complex and impractical, and gets worse with more nodes.

    This project presents a framework that utilizes Hadoop’s resource manager YARN to manage distributed TensorFlow applications. The proposal is a native YARN application with one ApplicationMaster (AM) per job, utilizing the AM as a registry for discovery prior to job execution. Conforming TensorFlow code to the framework typically is about a few lines of code.

    In comparison to TensorFlowOnSpark, the user experience is very similar, and collected performance data indicates that there exists an advantage of running TensorFlow directly on YARN with no extra layer in between.

  • Astner, Josephine
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Initiating an Internet of Things Ecosystem inPractice: A qualitative study carried out at IBM Sweden2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things (IoT) concludes a network of physical objects equipped withdigital technologies to interact with people and other objects. IoT brings challenges,one way for organisations to address these challenges is by business ecosystems accordingto the analogy of natures ecosystem. This study defines an IoT oriented businessecosystem as an IoT ecosystem, because of the definitions used in the market varies.The purpose of this study was to investigate the critical factors for a working IoTecosystem, as well as propose how these factors can be applied in practice, since thisis absent in the market. A customized research design was conducted for this studyto manage the 17 semi-structured interviews at IBM. The interviews were divided initerations with di↵erent themes, where the result of each iteration was the base forthe decision of the next iteration theme. The result of this study reflected severalcritical perspectives of how to create an IoT ecosystem with partnership, end-userand scalability were recurrent. The conclusion of this were six critical factors of howan organisation can initiate an IoT ecosystem anchored with a product, as well as atool of how to apply these factors in practice.

  • Wang, Chen
    KTH, School of Engineering Sciences (SCI), Physics.
    A Preliminary Design Study for a Small Passive Lead-bismuth Cooled Fast Reactor2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Eneborg, Alexander
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Improvement and Characterization of Aqueous Graphene Dispersions2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis