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  • Theodórsson, Snorri Rafn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Quantifying Static and Dynamic Stability in Amputees with Low Activity2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Background: Approximately 67% of lower limb amputees fall once or more every year. It is important for their daily functioning and their social life that their prosthetic device provide them with stability and security. Measuring stability for amputees and their prosthetic devices is challenging, especially for amputees with low activity level. However, it is important for the users and the product designers to know if the products are actually providing the user with more stability.

    Objective: The aim of the study is to create a measurement protocol to quantify static and dynamic stability with enough sensitivity to differentiate between two prosthetic products for amputees with low activity level.

    Methods: Ten K2, unilateral transtibial subjects were recruited and 6 of them completed the protocol during a 2-hour visit. They repeated the same protocol for two prosthetic feet, K2C (Össur, Iceland) and K2 Sensation (Össur, Iceland). In order to compare the static and dynamic stability of the subjects and the products, three different tests and one questionnaire were used: Static standing test, Limit of Stability (LOS) test, Walking on level ground, and the Activities-specific Balance Confidence scale (ABC scale).

    Results: For the static standing test, the K2Sensation showed less range for the center of pressure in the anteroposterior direction while standing in a normal position with the eyes open. However, the participants were able to reach further (LOS test) over their prosthetic side while wearing the K2C foot. For the K2C foot, gait parameters such as ankle power, positive work, self selected walking speed and the range of motion in the prosthetic ankle all increased. The backward margin of stability (BwMOS) only increased for 2 participants who had it in common to both wear ProFlex-XC in daily life. No difference was seen in perceived stability according to the ABC scale.

    Conclusion: The aim of the study was reached. Static and dynamic stability were quantified and distinguished between the 2 different prosthetic feet. It is concluded that both the static standing test and the LOS test are necessary parts of the protocol as they capture different aspects of static stability. For future studies, a longer adaptation time is suggested for the participants to achieve a stable gait pattern and to answer the ABC scale with more reliability

  • Bång, Stina
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    The role of groundwater in the inundation of a river-connected floodplain: case study of the river Silverån in southeast Sweden2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Fluvial flooding has long been recognized as one of the most frequently occurring natural disasters worldwide, with consequences as large economic losses from damages on infrastructure and agriculture, as well as severe impacts on human health. A less known and explored type of flooding is groundwater flooding. A flood type that for instance can arise in river-connected floodplains when groundwater levels rise to the ground surface due to increased river stages in the watercourse. Although groundwater flooding in general is a poorly understood phenomenon, it has become more recognized since its inclusion in the European Floods Directive (2007/60/EC) in 2007. Sweden has however excluded pure groundwater flooding as a separate flood type in its interpretation of the directive, but recognizes groundwater as a component which together with soil water and river water can influence the appearance of a flood event. One of the difficulties regarding groundwater floods that occur in connection to a river is that they typically are hard to differentiate from inundations of fluvial or pluvial origin. It is however important to address the role of groundwater in the inundation of these settings, since traditional flood protection strategies like levees might be circumvented by flows through the subsurface.

    The aim of this study has been to investigate the role of groundwater in the flooding of a river-connected floodplain by setting up a groundwater model in the integrated hydrological modeling tool MIKE SHE and couple it to an existing MIKE 11 river model, developed by DHI. The study area is a floodplain located along the river Silverån, a tributary to the river Emån, located in the south eastern part of Sweden. By running the model using four different sub-scenarios, regarding initial groundwater level and amount of precipitation, flood extent and contribution of groundwater to the inundation, in relation to other flood sources, has been investigated for different river discharges. A scenario with artificial levees constructed along parts of the river was also examined as levees have been found to have little effect on groundwater floods.

    As the model provides a simplified and generalized representation of reality it possesses several uncertainties, and so does the results. In summary, the results are in line with what is stated in the Swedish interpretation of the European Floods directive. It has not been possible to demonstrate pure groundwater flooding, but the results suggest that an elevated groundwater level in the beginning of a flood event will increase the extent of the inundation and result in a larger contribution of groundwater to the total amount of flood water. This suggests that there, in some cases, might be a value in integrating groundwater processes in flood risk mapping. Something that is not included in the conventional hydraulic 1D and 2D models, which traditionally are used in flood mapping.

    As could be expected, the results indicate that groundwater only accounts for a minor part of the flood water added to the total floodplain, while the major sources are river water and surface runoff. A delimited floodplain section that was investigated more in detail, as an increased flow from groundwater to overland water was detected along it, did however show larger contributions from groundwater. This river reach was less vulnerable to fluvial flooding, which in total resulted in a less severe flood, but also enabled a larger amount of groundwater to seep up to the floodplain surface. These conditions did also result in that the river section experienced a worsened inundation at the sub-scenario of high precipitation and high initial groundwater level, as levees were constructed along the river. Most likely because a lot of surface runoff, otherwise able to drain to the river along this section, got trapped outside the levees since it was unable to drain both to the river and to the saturated ground. These results support the theory that levees have little impact on groundwater flooding and stresses the importance 0f surveying and understanding the governing processes in the inundation of a floodplain when planning which type of flood protection scheme to use.

  • Kilander, Sara
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    How can artificial intelligence-based sorting solutions support the realisation of circular economy and closed loop recycling of scrap tyres: A case study at Ragn-Sells2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Tyre rubber is a lightweight, elastic, shock- and noise absorbing, UV resistant, insulating material with high tensile strength that perform well in a broad range of temperatures. These are all valuable qualities that point to the benefit of recycling and reusing the material in high quality products and applications for as long as possible.

    Technological progress and development of products often leads to high tech solutions, aiming for optimised comfort and safety. Unfortunately, this might complicate the recycling and possible end-oflife applications for new products. For instance, the European Tyre & Rubber Manufacturers Association (ETRMA) has raised awareness to recyclers and granulators that self-sealant liquids obstruct recycling and lead to heat build-up and potential fire hazards. Tyre manufacturers therefore recommend that sealant tyres are collected separately and sent to energy recovery, how and by whom is not yet decided. This master thesis provides an overview of the changes demanded in the waste management of tyres to increase the reusability and which barriers that most frequently derail or slow it down. The research is built on circular economy strategies that aims for closed loop tyre recycling and evaluate to which extend this can be obtained when using artificial intelligence and image recognition to sort scrap tyres in the recycling facilities. The sorted tyres enable an end-of-life application that is specially design for varying tyre qualities.

    The reusability of post-consumer tyres can increase if combining material knowledge with pre-sorting of tyres to suit niched applications. The more material knowledge, the higher the quality of the reclaimed rubber and the modified, upgraded and refined materials can be recycled in high quality applications, optimal as feedstock in the production of new tyres. It can appear hard to use image recognition to distinguishing small labels on scrap tyres, nevertheless, sorting results provided when identifying the 3PMSF label showed high prediction rates, 87.3% of the existing 3PMSF labels was identified and only 1.6% predictions were false. Regardless of the sorting possibilities, material recycling of rubber is hard, especially when aiming for high quality products. The most promoted treatment is devulcanisation, having the highest possibility of recirculating scrap tyre rubber in the production of new. The main barrier is the three-dimensional crosslink structure in the rubber that is hard to break without damaging the polymers in the devulcanisation process. There are many new trends and technologies within scrap tyre recycling. Jointly, the efficiencies need to be higher. Other obstacles to overcome include; political constraints, the negative reputation that tyre rubber is a hazardous material, high costs pricing in relation to virgin feedstock materials and end-of-life application that can handle the huge amount of scrap tyres being discharged yearly. Massimo Cialone, product developer at Hankook Tyres captured the lack of regulations and political ventures when he at this springs Future Tyre Conference said, “We need legislation!”.

    The car industry is going towards a new era, autonomous cars are expected in the near future and regulatory requirements are forcing mobility towards electric vehicles. Moreover, congestion in cities and mobility needs are pushing a shift towards shared mobility. With so many unknown trends it is not yet possible to forecast the future of tyre development, neither to predict which new materials that might aggravate the recycling of scrap tyres in the future. Therefore, the advantages of an autonomous sorting platform that can be updated whenever new tyres and sorting approaches are identified is a great investing for Ragn-Sells.

  • Acuner, Zeynep
    et al.
    KTH, Skolan för teknikvetenskap (SCI).
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Clustering of gamma-ray burst types in the Fermi GBM catalogue: indications of photosphere and synchrotron emissions during the prompt phaseShow affiliations2018Inngår i: Monthly Notices of the Royal Astronomical Society, Vol. 475, nr 2, s. 1708-1724, artikkel-id stx3106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many different physical processes have been suggested to explain the prompt gamma-ray emission in gamma-ray bursts (GRBs). Although there are examples of both bursts with photospheric and synchrotron emission origins, these distinct spectral appearances have not been generalized to large samples of GRBs. Here, we search for signatures of the different emission mechanisms in the full Fermi Gamma-ray Space Telescope/GBM (Gamma-ray Burst Monitor) catalogue. We use Gaussian Mixture Models to cluster bursts according to their parameters from the Band function (α, β, and Epk) as well as their fluence and T90. We find five distinct clusters. We further argue that these clusters can be divided into bursts of photospheric origin (2/3 of all bursts, divided into three clusters) and bursts of synchrotron origin (1/3 of all bursts, divided into two clusters). For instance, the cluster that contains predominantly short bursts is consistent of photospheric emission origin. We discuss several reasons that can determine which cluster a burst belongs to: jet dissipation pattern and/or the jet content, or viewing angle.

  • Göran, Fransson
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Analysis of current methods when using ergometer cycles for training and testing of fitness2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • Disputas: 2020-01-10 14:00 Kollegiesalen, Stockholm
    Frid, Emma
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Människocentrerad teknologi, Medieteknik och interaktionsdesign, MID.
    Diverse Sounds: Enabling Inclusive Sonic Interaction2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This compilation thesis collects a series of publications on designing sonic interactions for diversity and inclusion. The presented papers focus on case studies in which musical interfaces were either developed or reviewed. While the described studies are substantially different in their nature, they all contribute to the thesis by providing reflections on how musical interfaces could be designed to enable inclusion rather than exclusion. Building on this work, I introduce two terms: inclusive sonic interaction design and Accessible Digital Musical Instruments (ADMIs). I also define nine properties to consider in the design and evaluation of ADMIs: expressiveness, playability, longevity, customizability, pleasure, sonic quality, robustness, multimodality and causality. Inspired by the experience of playing an acoustic instrument, I propose to enable musical inclusion for under-represented groups (for example persons with visual- and hearing-impairments, as well as elderly people) through the design of Digital Musical Instruments (DMIs) in the form of rich multisensory experiences allowing for multiple modes of interaction. At the same time, it is important to enable customization to fit user needs, both in terms of gestural control and provided sonic output. I conclude that the computer music community has the potential to actively engage more people in music-making activities. In addition, I stress the importance of identifying challenges that people face in these contexts, thereby enabling initiatives towards changing practices.

  • Zhang, Kewei
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Nätverk och systemteknik. KTH Royal Institute of Technology.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Nätverk och systemteknik. RISE SICS.
    Safeguarding NMA Enhanced Galileo OS Signals from Distance-Decreasing Attacks2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Increased use of global satellite navigation systems (GNSS), for applications such as autonomous vehicles, intelligent transportationsystems and drones, heightens security concerns. Civil GNSS signals are vulnerable to notably spoofing and replayattacks. To counter such attacks, cryptographic methods are developed: Navigation Message Authentication (NMA) is onesuch scheme, about to be deployed for Galileo E1 Open Service (OS); it allows receivers to verify the signal origin andprotects navigation message integrity. However, NMA signals cannot fully thwart replay attacks, which do not require forgingnavigation messages. Classic replay attacks, e.g, meaconing, retransmit previously recorded signals without any modification,thus highly limiting the capacity of the adversary. Distance-decreasing (DD) attacks are a strong type of replay attack,allowing fine-grained individual pseudorange manipulation in real time. Moreover, DD attacks counterbalance processing andtransmission delays induced by adversary, by virtue of shifting earlier in time the perceived (relayed) signal arrival; thusshortening the pseudorange measurements. In this paper, we first analyze how DD attacks can harm the Galileo E1 OSNMAservice assuming the adversary has no prior information on the navigation message. Moreover,we propose a DD attackdetection method based on a Goodness of Fit test on the prompt correlator outputs of the victim. The results show that themethod can detect the DD attacks even when the receiver has locked to the DD signals.

  • de Lange, Geertje
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Bringing people together through housing and combatting loneliness: Understanding the role of housing in stimulating social support and combatting loneliness among elderly and young adults2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The high prevalence of loneliness, especially among elderly and young adults, calls for measures to connect people and strengthen social support networks. Housing models that bring people together and reduce loneliness are seen as a solution. The theory implies a causal relation in which the building design can stimulate social interaction, contribute to social support, and combat loneliness. This research aims to get an insight in the way different housing models for elderly and young adults can stimulate social support and combat loneliness, by looking at social contact design principles. The research consists of six qualitative case studies spread over Sweden, the Netherlands and Austria. Among the case studies there are two nursery homes, two student accommodations and two co-housing initiatives. The data is collected within a period of five weeks, using the go-along method, in-depth interviews and diaries. The research confirms the causal relation between building design, social interactions and social support. However, it was found that loneliness must be considered separate from this. While housing models cannot combat loneliness, they can stimulate social interactions between residents that help to build a social support network. In addition, the housing situation cannot cause loneliness, but it can reinforce an already existing feeling of loneliness among residents by hindering possibilities for residents to interact and build social support networks. Based on the research findings, two policy recommendations are made. First of all, future housing models should aim to integrate students and elderly within the wider society. Second, future housing models should offer a building design and organizational structure that stimulate social interaction and social support between residents.

  • Ahlin Marceta, Jesper
    Filosofi och historia, KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Filosofi och teknikhistoria, Filosofi.
    Respect the Author: a Research Ethical Principle for Readers2019Inngår i: Journal of Academic Ethics, ISSN 1570-1727, E-ISSN 1572-8544, s. 1-11Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Much of contemporary research ethics was developed in the latter half of the twentieth century as a response to the unethical treatment of human beings in biomedical research. Research ethical considerations have subsequently been extended to cover topics in the sciences and technology such as data handling, precautionary measures, engineering codes of conduct, and more. However, moral issues in the humanities have gained less attention from research ethicists. This article proposes an ethical principle for reading for research purposes: Respect the author.

  • Disputas: 2020-01-27 13:00 F3, Stockholm
    Rubensson, Isak
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Systemanalys och ekonomi. Trafikförvaltningen, Region Stockholm.
    Making Equity in Public Transport Count2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Political and public focus on equity and justice outcomes of public policies is on the rise all over the world. Equity is both philosophically motivated and often decreed by law and in planning directives to be monitored when policies are changed, however oftentimes these equity assessments are vague, qualitative and carries low weight in policy decision processes. For the public transport administrator, all decisions on operations, fare management and subsidies have distributional consequences forming the equity outcomes of public transport provision. In this thesis distributional outcomes of public transport subsidies, fare schemes, transport quality provision and public transport accessibility are studied quantitatively. New methodology is developed with regard to assignment of subsidy level per individual trip, graphics on geographical fare distribution and a measure of vertical distribution. Some findings are that public transport subsidies have low horizontal but high vertical equity, that flat fares – contrary to much of the literature- have high vertical equity when cities have high income residents living centrally. Women place higher weight on crowding as a quality issue, older passengers put both higher weight and higher satisfaction on low time variability while young passengers are less satisfied with and places lower weight on personnel attitude. And that accessibility, controlled for how densely populated and central the residence-area is, has a vertically equitable distribution.

  • Andersson, Andreas
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Bro- och stålbyggnad.
    Karoumi, Raid
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Bro- och stålbyggnad. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Tidigare Institutioner (före 2005), Byggkonstruktion.
    A soil-steel bridge under high-speed railways2017Inngår i: Archives of Institute of Civil Engineering / [ed] Arkadiusz Madaj, Iwona Jankowiak, Poznan, 2017, Vol. 23, s. 45-52Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents some recent research on railway bridge dynamics with application to buried flexible structures. Based on a combination of simulations and full-scale testing, current research indicates that a rather comprehensive numerical model is required to accurately describe the response from passing trains.

  • Disputas: 2020-01-17 14:00 F3, Stockholm
    Vallejos, Pablo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Fusionsplasmafysik.
    Modeling RF waves in hot plasmas using the finite element method and wavelet decomposition: Theory and applications for ion cyclotron resonance heating in toroidal plasmas2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Fusion energy has the potential to provide a sustainable solution for generating large quantities of clean energy for human societies. The tokamak fusion reactor is a toroidal device where the hot ionized fuel (plasma) is confined by magnetic fields. Several heating systems are used in order to reach fusion relevant temperatures. Ion cyclotron resonance heating (ICRH) is one of these systems, where the plasma is heated by injecting radio frequency (RF) waves from an antenna located outside the plasma.

    This thesis concerns modeling of RF wave propagation and damping in hot tokamak plasmas. However, solving the wave equation is complicated because of spatial dispersion. This effect makes the wave equation an integro-differential equation that is difficult to solve using common numerical tools. The objective of this thesis is to develop numerical methods that can handle spatial dispersion and account for the geometric complexity outside the core plasma, such as the antenna and low-density regions (or SOL). The main results of this work is the development of the FEMIC code and the so-called iterative wavelet finite element scheme.

    FEMIC is a 2D axisymmetric code based on the finite element method. Its main feature is the integration of the core plasma with the SOL and antenna regions, where arbitrary geometric complexity is allowed. Moreover, FEMIC can apply a dielectric response in the SOL and in the region between the SOL and the core plasma (i.e. the pedestal). The code can account for perpendicular spatial dispersion (or FLR effects) for the fast wave only, which is sufficient for modeling harmonic cyclotron damping and transit time magnetic pumping. FEMIC was used for studying the effect of poloidal phasing on the ICRH power deposition on JET and ITER, and was benchmarked against other ICRH modeling codes in the fusion community successfully.

    The iterative wavelet finite element scheme was developed in order to account for spatial dispersion in a rigorous way. The method adds spatial dispersion effects to the wave equation by using a fixed point iteration scheme. Spatial dispersion effects are evaluated using a novel method based on Morlet wavelet decomposition. The method has been tested successfully for parallel and perpendicular spatial dispersion in one-dimensional models. The FEMIC1D code was developed in order to model ICRH and to study the properties of the numerical scheme. FEMIC1D was used to study second harmonic heating and mode conversion to ion-Bernstein waves (IBW), including a model for the SOL and pedestal. By studying the propagation and damping of the IBW, we verified that the scheme can account for FLR effects.

  • Fathli, Margareta
    et al.
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Karjalainen, Karolina
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Kronman, Ulf
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Open Access Publishing at the KTH Royal Institute of Technology: Statistics for 2011-20142016Rapport (Annet vitenskapelig)
    Abstract [en]

    During 2011, a policy for scholarly publishing was implemented at KTH.1 The policy states that researchers at KTH should strive to publish open access, either through well-reputed open accessjournals or by self-archiving in KTH publication database DiVA. Publications published by KTH – i.e dissertations, bachelor and master theses, reports – are to be self-archived in DiVA as a general rule. In this report, shares and trends of open access publishing at KTH are analysed starting from the same year the policy was implemented, in 2011. A report that analyses open access at KTH will then be released annually

  • Fathli, Margareta
    et al.
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Karjalainen, Karolina
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Kronman, Ulf
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Open Access Publishing at the KTH Royal Institute of Technology: Statistics for 2011 - 20152016Rapport (Annet vitenskapelig)
    Abstract [en]

    During 2011, a policy for scholarly publishing was implemented at KTH.1 The policy states that researchers at KTH should strive to publish open access, either through well-reputed open accessjournals or by self-archiving in KTH publication database DiVA. Publications published by KTH – i.e dissertations, bachelor and master theses, reports – are to be self-archived in DiVA as a general rule. In this report, shares and trends of open access publishing at KTH are analysed starting from the same year the policy was implemented, in 2011. A report that analyses open access at KTH will then be released annually.

  • Monés Pederzini, Óscar
    KTH, Skolan för industriell teknik och management (ITM).
    Integrating Energy Demand and Ability to Pay in the Design of Decentralised Energy Supply: A Case Study in Rural Nepal2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Access to electricity is essential for socioeconomic growth, especially in developing countries. However, over 1.1 billion people still do not have access to modern sources of energy. This is particularly prevalent in rural or remote areas, where renewable off-grid solutions and particularly minigrids seem the most cost-effective solution to deliver longterm energy solutions. Comprehensively forecasting energy demand in these areas and designing the most optimal solution requires a thorough feasibility design process. A literature review of project development tasks revealed that a research gap regarding how the household’s ability to pay relates with the project’s cost exists. This frequently leads to viability gaps, which demand costly and time-consuming manual adaptations to the project’s design. The goal of the study was to adapt household’s ability to pay and energy demand assessment at early stages of minigrid design so as to avoid these adaptations at later stages. Rural Nepal was chosen as a case study, and an extensive energy household survey based on multidimensional energy access parameters developed by the Reiner Lemoine Institute was used. The data employed was collected from 9 different rural municipalities from Province Number 1 and Province number 7, with a total of 3600 surveyed households. Households were clustered into three wealth groups, using socioeconomic variables such as education, financial status, owned and desired electrical appliances and willingness to pay. The construction of a stochastic load modeller using R allowed translating the energy needs of each wealth groups into load profiles. The most common energy services for the different clusters are lighting and communication for group 1, plus entertainment and space cooling for group 2, plus occasional thermal loads or base loads (fridge) for group 3. A cost estimator was built through a linear regression to obtain an overall project cost estimation based on the customer distribution. In parallel, household estimated-energy-expenditures were determined by allocating a literature-accepted percentage of their total annual expenditures over the entire project lifetime. This value was averaged for each municipality and wealth group, and a community’s minigrid economic potential was determined using the municipality’s average customer distribution as a reference. By using this and the cost estimator, it is possible to quantify a potential viability gap based on the customer distribution. An automated adaptation tool was designed in R to obtain the most similar feasible customer distribution when a viability gap is encountered. This is done by fixing the economic potential and using the customer distribution and its associated cost as a variable. Results show that in all but one municipality, providing households with basic energy services is viable, while an average grant of 75 USD per type 2 household and 515 USD per type 3 household for the entire project life-time is required. Additionally, only three municipalities suggest a feasible average customer distribution, while the rest required adaptation. However, a significant regional heterogeneity exists, suggesting that location-specific policies are required to optimise the effects of subsidies. The study also shows that while the demand for higher energy services exists in rural Nepal, there is a significant lack of available income that impedes this supply, and policy makers and energy planners should work to bridge this gap in order to foster socioeconomic development.

  • Karjalainen, Karolina
    et al.
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Minguillo, David
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Avdelningen för bibliotek, språk och ARC, Bibliotek, Publiceringens infrastruktur.
    Open Access Publishing at the KTH Royal Institute of Technology: Statistics for 2011 – 20162017Rapport (Annet vitenskapelig)
    Abstract [en]

    During 2011, a policy for scholarly publishing was implemented at KTH.1 The policy states that researchers at KTH should strive to publish open access, either through well-reputed open accessjournals or by self-archiving in KTH publication database DiVA. Publications published by KTH – i.e. dissertations, bachelor and master theses, reports – are to be self-archived in DiVA as a general rule. In this report, shares and trends of open access publishing at KTH are analysed starting from the same year the policy was implemented, in 2011. A report that analyses open access at KTH will be released annually.

  • Gkiolia, Maria
    KTH, Skolan för industriell teknik och management (ITM).
    Preventive actions to eliminate supply chain losses in Kraft Heinz Company2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of the presented project is to eliminate the supply chain losses in Kraft Heinz Company through preventive actions. The two points that the current thesis will focus on are the prevention of excess production and the elimination of MOQ (Minimum Order Quantity) issues that contribute to supply chain losses. High MOQ is one of the main root causes of excess production.

    Firstly, a literature review will be made. The approach of creating the literature framework is to start from a general description of supply chain activities in FMCG (Fast-moving Consumer Goods) companies, then to focus on more specific topic which is the excess stock and the inventory management and finally, to end up in the food waste hierarchy analysis that scientific articles frame. Food waste for a FMCG company is similar to supply chain losses, thus it is critical to provide a state-of-art literature in order to have a better understanding.

    Furthermore, the KHC (Kraft Heinz Company) background will be described, as the history of KHC and the current portfolio in order to understand the size of the company and the needs of such a huge company and the complexities. Additionally, the supply chain function in KHC will be described in details in order to understand the reason of this thesis existence, to identify the gaps in this process and the improvements should be made.

    Finally, the improvements made through this project will be presented, as well as, the processes and the methods that are developed and standardized. The analysis of the prevention of excess production process, as well as, the improvements have been made in this process will be explained. The routines and the new approaches will be described. The second part of the improvements section is concerned the development and the standardization of the MOQ Flexibility project. The calculations, the process, the challenges and the involved stakeholders will be part of this thesis.

  • Pondini, Antonio
    KTH, Skolan för industriell teknik och management (ITM).
    A new strategic overcome of the challenges inherent to the role of the aggregator in the Italian balancing market2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The European Union is currently driving forward the development of an energy model that is more reliant on renewable supply. Indeed, recent European Commission figures estimate a renewable penetration of 50% by 2030. As well as a shift towards renewables, our reliance on electricity is also set to dramatically increase in coming years, largely due to the inevitable electrification of vehicles and heating/cooling systems. Further to this, daily lives becoming less regimented and predictable is making energy use patterns more irregular. All of these factors are increasing the need for greater flexibility from our energy model so as to balance demand and supply.

    Improved flexibility and demand side management are crucial for the European Union so that it can meet its decarbonisation goals. Furthermore, taking into consideration the continued decommissioning of fossilbased power sources across the region, flexibility will need to take new forms. This is also growing demand for both companies and households to shift from being consumers to prosumers through the localised integration of renewable energy resources. A higher number of prosumers equates to higher flexibility and this could have significant impact of supporting grid stability.

    For prosumers to access flexibility markets, and in turn, support the decarbonisation of our energy system, there is need for a new player in the energy value chain – the aggregator. The aggregator should be the force that connects prosumers with transmission system operators, distribution system operators, and balance responsible parties (BRP).

    The role of aggregator can be done by pre-existent market stakeholders (e.g. suppliers). Both regulators and industry bodies agree that demand-side management and response will become of increasing importance as the energy system develops in coming years and aggregators will be fundamental for this transition.

    With Resolution 300/2017, Italy has defined the criteria to allow demand, “relevant production units” from non-programmable renewable sources, “non relevant units” (i.e. distributed generation), as well as accumulation systems to participate in the flexibility market.

    To date, 24 subjects have decided to take part as aggregators in the balancing market. If the interest of the main market operators in the aggregation of flexibility resources is evident, the need for an adjustment of the regulatory framework that, overcoming the barriers and obstacles currently existing, can encourage a greater participation is equally clear.

    Despite this, there remains to be much debate over how aggregation should best be implemented, and what regulatory framework needs to be put in place so that it can effectively support flexibility markets. Various aggregator implementation methods have already been proposed internationally. However, for a truly robust, integrated, and clear flexibility market, there is still need for more clarity on its roles and processes.

  • Lundmark, Lukas
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Synthetic Meta-Learning:: Learning to learn real-world tasks with synthetic data2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Meta-learning is an approach to machine learning that teaches models how to learn new tasks with only a handful of examples. However, meta-learning requires a large labeled dataset during its initial meta-learning phase, which restricts what domains meta-learning can be used in. This thesis investigates if this labeled dataset can be replaced with a synthetic dataset without a loss in performance. The approach has been tested on the task of military vehicle classification. The results show that for few-shot classification tasks, models trained with synthetic data can come close to the performance of models trained with real-world data. The results also show that adjustments to the data-generation process, such as light randomization, can have a significant effect on performance, suggesting that fine-tuning to the generation process could further improve performance.

  • Yin, Wenjie
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Machine Learning for Adaptive Cruise Control Target Selection2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Vehicles will be more complex, safe, and intelligent in the future. For instance, with the support of the advanced driver assistance system (ADAS), the safety and comfort of the driver and the passengers can be significantly improved. This degree project proposes data-driven solutions for adaptive cruise control (ACC) target selection that can be used to select one of the preceding vehicles as the primary target that similar to the choice of human drivers. This master degree project was carried out at Scania CV AB. A shared-network and a shared-LSTM network were used to select the primary target. Besides, A novel machine learning based target selection model (compare-target model) was designed, which can consider all neighboring vehicles together by comparing vehicles. A compare-target network and a compare-target XGBoost are developed based on the compare-target model. In total, four different machine learning methods were adopted to select the primary target for ACC, includ- ing a shared network, a shared-LSTM network, a compare-target network, and a compare-target XGBoost model. These methods were compared and analyzed. Fine-tuning was adopted to overcome the data imbalance problem of rare situations. The compare-target XGBoost can achieve 94.85% accuracy on the test set.

  • Öhman, Wilhelm
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Data augmentation using military simulators in deep learning object detection applications2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    While deep learning solutions have made great progress in recent years, the requirement of large labeled datasets still limit their practical use in certain areas. This problem is especially acute for solutions in domains where even unlabeled data is a limited resource, such as the military domain. Synthetic data, or artificially generated data, has recently attracted attention as a potential solution for this problem.

    This thesis explores the possibility of using synthetic data in order to improve the performance of a neural network aimed at detecting and localizing firearms in images. To generate the synthetic data the military simulator VBS3 is used. By utilizing a Faster R-CNN architecture multiple models were trained on a range of different datasets consisting of varying amounts of real and synthetic data. Moreover, the synthetic datasets were generated following two different philosophies. One dataset strives for realism while the other foregoes realism in favor of greater variation. It was shown that the synthetic dataset striving for variation gave increased performance in the task of object detection when used in conjunction with real data. The dataset striving for realism gave mixed results.

  • Sciaky, Davide
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    The digital transformation of the music industry through applications of blockchain technology2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Since its introduction in 2008, the blockchain technology has been hailed as the one that could revolutionise many different industries. The music industry underwent several changes in the last 20 years as a consequence of phenomena such as music piracy, digital music and music streaming. Many considered the blockchain technology the solution to the many issues the music industry is facing. However, while the technology has been around for more than 10 years, and despite the enthusiasm of scholars and experts, little has been done to actually implement blockchains in the industry, especially by its biggest players. The resulting question is if and how the technology could change the music industry. This research starts by looking into previous studies on the blockchain technology, on the music industry and on the possible intersections of the two: from there the most popular suggested applications of the blockchain technology are extracted and presented in interviews to people working in the music industry. The goal of the interviews is to understand if the issues that the suggestions aimed to solve are real, and if the suggested applications are thought to be actually useful. The results are also compared with considerations from previously analysed papers, and showed a general interest in the blockchain technology and in the belief that it could help solve some issues of the music industry. At the same time, it was found that the technology is considered too young to be employed at the present time, with most people reckoning it is a technology that could have an impact in 10-15 year time.

  • Lartigau, Baptiste
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Nonparametric Bayesian models for security anomaly detection2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Avionics systems are growing ever more complex to accommodate to the evolving needs of airlines. As such, their attack surface has greatly expanded, and the potential impact of a security incident touching these systems has become a critical concern for the aerospace industry. Countermeasures include defining security perimeters and monitoring network traffic, and in turn inspecting the logs generated by these systems to reveal security incidents and respond quickly accordingly. However, processing the large amount of system logs to extract valuable information is intractable through conventional means such as manual human investigation or regular expression matching.

    This thesis tackles the problem of automation of anomaly detection on security and functional system logs using advanced machine learning techniques. It investigates new methods to improve on the work done during a previous project at Collins Aerospace on Markov chains and LSTM neural networks. In particular, it evaluates the use of nonparametric Bayesian methods to perform this task, specifically the Hidden Dirichlet Process Hidden Markov Model. A complete log analysis system is proposed based on these models, and their performance is evaluated on real-life datasets using this framework.

  • Bolin, Tobias
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Nonlinear Approximative Explicit Model Predictive Control Through Neural Networks: Characterizing Architectures and Training Behavior2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Model predictive control (MPC) is a paradigm within automatic control notable for its ability to handle constraints. This ability come at the cost of high computational demand, which until recently has limited use of MPC to slow systems. Recent advances have however enabled MPC to be used in embedded applications, where its ability to handle constraints can be leveraged to reduce wear, increase efficiency and improve overall performance in everything from cars to wind turbines. MPC controllers can be made even faster by precomputing the resulting policy and storing it in a lookup table. A method known as explicit MPC.

    An alternative way of leveraging precomputation is to train a neural network to approximate the policy. This is an attractive proposal both due to neural networks ability to imitate policies for nonlinear systems, and results that indicate that neural networks can efficiently represent explicit MPC policies. Limited work has been done in this area. How the networks are setup and trained therefore tends to reflect recent trends in other application areas rather than being based on what is known to work well for approximating MPC policies. This thesis attempts to alleviate this situation by evaluating how some common neural network architectures and training methods performs when used for this purpose. The evaluations are carried out through a literature study and by training several networks with different architectures to replicate the policy of a nonlinear MPC controller tasked with stabilizing an inverted pendulum.

    The results suggest that ReLU activation functions give better performance than hyperbolic tangent and SELU functions; and that dropout and batch normalization degrades the ability to approximate policies; and that depth significantly increases the performance. However, the neural network controllers do occasionally exhibit problematic behaviors, such as steady state errors and oscillating control signals close to constraints.

  • Lousseief, Elias
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    MahlerNet: Unbounded Orchestral Music with Neural Networks2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Modelling music with mathematical and statistical methods in general, and with neural networks in particular, has a long history and has been well explored in the last decades. Exactly when the first attempt at strictly systematic music took place is hard to say; some would say in the days of Mozart, others would say even earlier, but it is safe to say that the field of algorithmic composition has a long history. Even though composers have always had structure and rules as part of the writing process, implicitly or explicitly, following rules at a stricter level was well investigated in the middle of the 20th century at which point also the first music writing computer program based on mathematics was implemented.

    This work in computer science focuses on the history of musical composition with computers, also known as algorithmic composition, using machine learning and neural networks and consists of two parts: a literature survey covering in-depth the last decades in the field from which is drawn inspiration and experience to construct MahlerNet, a neural network based on the previous architectures MusicVAE, BALSTM, PerformanceRNN and BachProp, capable of modelling polyphonic symbolic music with up to 23 instruments. MahlerNet is a new architecture that uses a custom preprocessor with musical heuristics to normalize and filter the input and output files in MIDI format into a data representation that it uses for processing. MahlerNet, and its preprocessor, was written altogether for this project and produces music that clearly shows musical characteristics reminiscent of the data it was trained on, with some long-term structure, albeit not in the form of motives and themes.

  • Argüello Ron, Diego
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Development of an Intelligent Embedded Interface for Interpreting Biosignals Recorded by Novel Wearable Devices2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In recent years there has been a considerable development in the realm of sensing technologies, embedded systems, wireless communication technologies, nanotechnologies, and miniaturization has made it possible to create smart wearable systems that can record data from the human bodies and monitor our daily activities. Most expectations for the successful deployment of wearable devices and their tangible impact for the society is in healthcare. Nevertheless, its use has been limited by the absence of intelligent mobile device interfaces able to process, analyse and inference the recorded data, giving relevant information to the user. On the other hand, new advances in nanotechnology have allowed the creation of so-called electronic skin, which consists in thin and flexible electrodes, easy and comfortable to use. This allows building new wearable devices able to record electrical activity from the surface of the body, which has a large diagnostic and monitoring potential.

    In this work, the goal is to study the feasibility of using these new sensors for continuous biopotential recording while supporting them with a mobile phone application able to receive, process and analyse the recorded biosignals in order to deliver useful feedback to the user in real-time. The wearable device known as Senso Medical Bio Pot V2 is proposed as a possible candidate to carry out electromyography (EMG), electrocardiography (ECG) and electroencephalography (EEG) recordings via skin tattoo electrodes. Moreover, an Android Application that connects to this device is created. It uses Machine Learning Algorithms embedded on it in order to classify the received signals. Finally, Long-Short Term Memory (LSTM) networks are implemented for classifying EEG and EMG signals.

    Several conclusions are derived from this work. Firstly, the device Senso Medical Bio Pot V2 is not suitable for its use as a wearable device for biosignal recording. Secondly, the Application designed and simulated offline achieves good performance. As a consequence, it could be used in the future with a suitable wearable sensor and offer good potential for processing and interpreting recorded biosignals with an opportunity to provide real-time feedback to the user in Brain-Computer Interface (BCI) type of applications.

  • Zheng, Jiaqi
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Interactive Visual Analytics for Agent-Based simulation: Street-Crossing Behavior at Signalized Pedestrian Crossing2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To design a pedestrian crossing area reasonably can be a demanding task for traffic planners. There are several challenges, including determining the appropriate dimensions, and ensuring that pedestrians are exposed to the least risks. Pedestrian safety is especially obscure to analyze, given that many people in Stockholm cross the street illegally by running against the red light. To cope with these challenges, computational approaches of trajectory data visual analytics can be used to support the analytical reasoning process. However, it remains an unexplored field regarding how to visualize and communicate the street-crossing spatio-temporal data effectively. Moreover, the rendering also needs to deal with a growing data size for a more massive number of people.

    This thesis proposes a web-based interactive visual analytics tool for pedestrians' street-crossing behavior under various flow rates. The visualization methodology is also presented, which is then evaluated to have achieved satisfying communication and rendering effectiveness for maximal 180 agents over 100 seconds. In terms of the visualization scenario, pedestrians either wait for the red light or cross the street illegally; all people can choose to stop by a buffer island before they finish crossing. The visualization enables the analysis under multiple flow rates for 1) pedestrian movement, 2) space utilization, 3) crossing frequency in time-series, and 4) illegal frequency. Additionally, to acquire the initial trajectory data, Optimal Reciprocal Collision Avoidance (ORCA) algorithm is engaged in the crowd simulation. Then different visualization techniques are utilized to comply with user demands, including map animation, data aggregation, and time-series graph.

  • Dong, Fanghong
    KTH, Skolan för industriell teknik och management (ITM).
    Cartesian Force Estimation of a 6-DOF Parallel Haptic Device2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The haptic device recreates the sense of touch by applying forces to the user. Since the device is “rendering” forces to emulate the physical interaction, the force control is essential for haptic devices. While a dedicated force/torque sensor can close the loop of force control, the additional equipment creates extra moving mass and inertia at the tool center point (TCP). Therefore, estimating the Cartesian force at the TCP has continuously been receiving attention over the past decades.

    The objective of this thesis project is to develop a real-time force estimation algorithm based on the proportional current-torque relationship with the dynamic modeling of the TAU haptic device. The algorithm can be further used for the force control of the device. The research questions of the thesis are: how to design and develop an algorithm for the TAU that used for Cartesian contact force estimation, how to set up the force estimation test bench and how to evaluate the results of the force estimation algorithm.

    In order to achieve the force estimation algorithm, a virtual environment is built to simulate the real-time haptic physics. Then an external force/torque sensor is installed at the TCP to get the measurement of the Cartesian force at the TCP. The force estimation algorithm calculates the Cartesian force at the TCP based on the current measurement of the DC motors at the six joints. The estimation result of the Cartesian force at the TCP is then compared with the force/torque sensor measurement to determine if the estimation algorithm is sufficiently accurate. The analysis of the estimation accuracy emphasizes the feasibility of Cartesian force estimation on the TAU haptic device.

  • Rosén, Anders
    et al.
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Lärande, Lärande i teknikvetenskap.
    Havtun, Hans
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lennholm, Helena
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Lärande, Lärande i teknikvetenskap.
    Framework for bottom-up integration of sustainable development in engineering educations2019Konferansepaper (Annet vitenskapelig)
  • Heshmati Alamdari, Shahab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Reglerteknik.
    Nikou, Alexandros
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Reglerteknik.
    Dimarogonas, Dimos V.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Reglerteknik.
    Robust trajectory tracking control for underactuated autonomous underwater vehicles2019Inngår i: Proceedings 2019 IEEE Conference on Decision and Control (CDC), 2019Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Motion control of underwater robotic vehicles isa demanding task with great challenges imposed by external disturbances, model uncertainties and constraints of the operating workspace. Thus, robust motion control is still an open issue for the underwater robotics community. In that sense, this paper addresses the tracking control problem of 3D trajectories for underactuated underwater robotic vehicles operating in a constrained workspace including obstacles. In particular, a robust Nonlinear Model Predictive Control (NMPC) scheme is presented for the case of underactuated Autonomous Underwater Vehicles (AUVs) (i.e., vehicles actuated only in surge, heave and yaw). The purpose of the controller is to steer the underactuated AUV to a desired trajectory with guaranteed input and state constraints inside a partially known and dynamic environment where the knowledge of the operating workspace is constantly updated on–line via the vehicle’s on–board sensors. In particular, by considering a ball which covers the volume oft he system, obstacle avoidance with any of the detected obstacles is guaranteed, despite the model dynamic uncertainties and the presence of external disturbances representing ocean currents and waves. The proposed feedback control law consists of two parts: an online law which is the outcome of a Finite Horizon Optimal Control Problem (FHOCP) solved for the nominal dynamics; and a state feedback law which is tuned off-line and guarantees that the real trajectories remain bounded in a hyper-tube centered along the nominal trajectories for all times. Finally, a simulation study verifies the performance and efficiency of the proposed approach.

  • Gustafsson, Christina
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande, Bygg- och fastighetsekonomi.
    Lind, Hans
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande, Bygg- och fastighetsekonomi.
    Lundström, Stellan
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande, Bygg- och fastighetsekonomi.
    Fastighetsvärdering: då, nu och i framtiden2019 (oppl. 1)Bok (Annet vitenskapelig)
    Abstract [sv]

    Boken ska ge de som utför eller tar del av fastighetsvärderingar en inblick i hur utvecklingen av synsätt och metoder varit för fastighetsvärdering sedan 1940-talet. Tanken är den vanliga vid historieskrivningar: Vad kan vi lära oss av historien när vi försöker blicka framåt?Värderingsbranschen förser samhället med beslutsunderlag för olika aktiviteter på fastighets- och byggmarknaderna. En titt tillbaka i tiden visar hur nya teorier och ny information tillsammans med teknikutveckling och entreprenörskap förändrar en hel bransch. De som nu funderar över hur en digitaliserad omvärld kan bidra till att skapa nya former av beslutsunderlag finner att steget från 1950-talets arronderingstal till nutidens algoritmer är mera semantiskt än innehållsmässigt.Denna bok om utvecklingen av fastighetsvärdering i Sverige har möjliggjorts genom en donation från Svenskt fastighetsindex SFI ekonomisk förening till KTH:s avdelning för bygg- och fastighetsekonomi vid institutionen för fastigheter och byggande inom ABE-skolan.

  • Campion, James
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Hassona, A.
    He, Z. S.
    Beuerle, Bernhard
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Gomez-Torrent, Adrian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Vecchiattini, S.
    Lindman, R.
    Dahl, T. S.
    Li, Y.
    Zirath, H.
    Oberhammer, Joachim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Toward Industrial Exploitation of THz Frequencies: Integration of SiGe MMICs in Silicon-Micromachined Waveguide Systems2019Inngår i: IEEE transactions on rehabilitation engineering, ISSN 1063-6528, E-ISSN 1558-0024, Vol. 9, nr 6, s. 624-636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new integration concept for terahertz (THz) systems is presented in this article, wherein patterned silicon-on-insulator wafers form all DC, IF, and RF networks in a homogeneous medium, in contrast to existing solutions. Using this concept, silicon-micromachined waveguides are combined with silicon germanium (SiGe) monolithic microwave integrated circuits (MMICs) for the first time. All features of the integration platform lie in the waveguide’s H-plane. Heterogeneous integration of SiGe chips is achieved using a novel in-line H-plane transition. As an initial step toward complete systems, we outline the design, fabrication, and assembly of back-to-back transition structures, for use at D-band frequencies (110ï¿œ170 GHz). Special focus is given to the industrial compatibility of all components, fabrication, and assembly processes, with an eye on the future commercialization of THz systems. Prototype devices are assembled via two distinct processes, one of which utilizes semiautomated die-bonding tools. Positional and orientation tolerances for each process are quantified. An accuracy of $\pm \text3.5\; μ \textm$, $\pm \text1.5 °$ is achieved. Measured $S$-parameters for each device are presented. The insertion loss of a single-ended transition, largely due to MMIC substrate losses, is 4.2ï¿œ5.5 dB, with a bandwidth of 25 GHz (135ï¿œ160 GHz). Return loss is in excess of 5 dB. Measurements confirm the excellent repeatability of the fabrication and assembly processes and, thus, their suitability for use in high-volume applications. The proposed integration concept is highly scalable, permitting its usage far into the THz frequency spectrum. This article represents the first stage in the shift to highly compact, low-cost, volume-manufacturable THz waveguide systems.

  • Glubokov, Oleksandr
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Xinghai, Zhao
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Campion, James
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Beuerle, Bernhard
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Multilayer Micromachined Dual-Mode Elliptic Cavities Filter With Axial Feeding at 270 GHz2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A silicon micromachined multilayer bandpass filters using dual-mode elliptic cavities at 270 GHz is shown.The cross-coupled filter has been designed taking into accountthe side-walls non-verticality. Good agreement with simulations has been obtained for the filter. Excellent performancein terms of losses has been demonstrated.

  • Disputas: 2020-01-31 14:00 K1, Stockholm
    Winberg-Wang, Helen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Kemisk apparatteknik.
    Water density impact on water flow and mass transport in rock fractures2020Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    One way of taking care of spent nuclear fuel is to place it in a geological repository. In Sweden, a three-barrier system is planned. The system is based on encapsulating the fuel in copper canisters. These are surrounded by bentonite clay and buried under 500 m of bedrock. As a part of the safety assessment, the Q-equivalent model is used to quantify the possible release of radioactive material. This model also describes the rate at which corrosive agents carried by seeping water in rock fractures can reach the canisters, which may affect the longevity of the canisters.

    The aim of this thesis was originally to develop an experimental, phys- ical model to visualize and validate the Q-equivalent model. However, the overarching theme of this work has been to study the effect of minor density differences that might be overlooked in experiments, both concentration- dependent and density-difference induced by light absorption.

    In the initial diffusion and flow-experiment and associated calculations and simulations, it was found that simple Q-equivalent can describe and quantify the mass transport in both parallel and variable aperture fractures. However, this is the case only if the density difference between seeping water and clay pore water is insignificant. It was found in experiments with dyes used to visualise the flow and diffusion patterns that even minimal density differences could significantly alter the flow pattern. Density differences can result from concentration gradients or be induced by light absorption. TheQ-equivalent model was extended to account for density-induced flow. The importance of density-induced flow due to concentration gradients at the setting of a long-term repository for nuclear waste was evaluated. It was found that concentration gradients are able to induce rapid vertical up- or downward flow. This could increase the overall mass transport of radioactive material up to the biosphere or carry it downward to larger depths.

  • Sjödin, Johan
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Varierande hinder och svårfångade möjligheter för språkintroduktionselever: En vansklig resa i tiden2019Independent thesis Advanced level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete utgår från ämnet matematik och bygger på intervjuer av språkintroduktionselever, möten och diskussioner med lärare samt resultat från ett delprov i matematik. Resultaten har tagits fram genom en bred, induktiv tematisk analys och beskriver elevuppfattningar kring hinder och möjligheter som de upplevt i undervisning före ankomst till Sverige respektive inom språkintroduktionsundervisning i Sverige. Studien ger också en bild av elevernas uppfattning om sina möjligheter att klara godkänt betyg i matematik och slutligen förs en diskussion kring vilka framgångsfaktorer som är nödvändiga att beakta för att ge språkintroduktionselever realistiska möjligheter att klara godkänt betyg.Svenska språket, som nytt akademiskt språk, framstår som en av de största utmaningarna i elevernas matematikundervisning. I arbetet framkommer likheter men framförallt skillnader mellan tidigare och nuvarande skolgång. Dessa är t.ex. skillnader mellan auktoritära och auktoritativa fostrans- och kommunikationsstilar samt skillnader i sociokulturellt grundade beteendemönster som är svårupptäckta och kan utgöra stora hinder i matematiklärandet i Sverige. Vissa elever visar på egna effektiva arbetsmetoder medan andra har behov av anknytning, stöd och hjälp för att finna nya sätt att arbeta och lära i en svensk skola med ökad frihet under ansvar.Enligt Skolinspektionens kvalitetsgranskning av språkintroduktionsutbildningen på 42 skolor (Skolinspektionen, 2017) varierade förutsättningarna för eleverna att nå måluppfyllelse avsevärt. Slutsatserna i detta examensarbete pekar på avgörande framgångsfaktorer för språkintroduktionsarbete som är förslag på åtgärder mot vissa av de tillkortakommanden som framkommit i Skolinspektionens kvalitetsgranskning.

  • Al Dewany, Nora
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Medborgardialogens makt och vanmakt: Fallstudie av Rosens röda matta sex år efter invigning2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Trots att levnadsförhållandena generellt sett ökar i hela världen växer skillnaderna i Sverige snabbare än i något annat OECD land. Världshälsoorganisationen WHO skriver i sin rapport Closing the gap in one generation att detta inte minst yttrar sig i ojämlikheten i hälsa. Hållbarhetsaspekterna har därför sedan länge kommit att inkludera sociala, ekonomiska och ekologiska värden, där alla tre är förutsättningar för varandra. WHO menar att ett relevant mått på social hållbarhet är ojämlikheten i hälsa. För att minska denna krävs därför förändringar inom samhällets alla sektorer. Inom stadsplanering är arbetet med medborgardeltagande ett verktyg för att öka den sociala hållbarheten. Detta har Malmö stad arbetat med i projektet Fokus Rosengård och i synnerhet dess delprojekt Rosens röda matta som är en aktivitetsyta i Rosengård. Denna yta har utformats av 13 unga kvinnor i samarbete med landskapsarkitekten på gatukontoret. Anledningen till att endast unga kvinnor involverades var för att projektledarna tidigt lärde sig att spontanidrottsplatserna i Sverige till 80% domineras av killar. Dialogerna som hållits har inkluderat olika nivåer av delaktighet och makt. De allra första dialogerna och workshops som involverade många invånare fungerade konsulterande. När platsen designades var det dock högre nivåer av makt som identifierades hos de 13 unga kvinnorna eftersom de hade stort inflytande över den fysiska utformningen. Från intervjuer av de olika projektledarna för Fokus Rosengård framgår en nöjdhet över resultatet eftersom syftet att öka attraktiviteten uppnåtts då det genererat ökade investeringar i området. Den största framgångsfaktorn som lyfts i samtliga intervjuer är dock de 13 unga kvinnorna vars engagemang för påverkan fortsatt även efter projektets slut. Endast en av de intervjuade vet hur platsen används idag och i hur stor utsträckning, men nöjdheten över projektet och stoltheten över de unga kvinnorna är stor ändå. Av intervjuer med huvudansvariga för Fokus Rosengård och slutrapporter där projektet utvärderats framgår att medborgardeltagande varit en viktig del för det sociala hållbarhetsarbetet, framförallt för hur det utvecklat de delaktiga unga kvinnorna. Därför diskuteras det i slutet på uppsatsen om inte dialoger hållits för dialogens skull och huruvida problematiskt eller inte det är med medborgardeltagande oavsett vilken nivå av makt och inflytande som ges. Det har inte varit möjligt att dra större slutsatser om den sociala hållbarheten ökat eller minskat av projektet Rosens röda matta. Däremot görs det tydligt av insamlat material att projektet varit en del av större förändringsarbeten i Rosengård som syftar till att förtäta och bygga om. En fråga kan vara om medborgardialoger hållits för att ge stort inflytande i mindre viktiga frågor och därmed hålla invånarna nöjda inför framtida större förändringar, där en av konsekvenserna kan vara gentrifiering av Rosengård

  • Attig, Stefan
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    The Organic Pattern of Space:: A Space Syntax Analysis of Natural Streets and Street Segments for Measuring Crime and Traffic Accidents2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The natural streets model is a research prototype that has been shown to perform better than the conventional GIS-based streets segments for explaining traffic flow and human movement. However, given its experimental status, a gap in the literature was identified. Therefore, the aim of this thesis was to contribute to the literature by investigating the wider applications of natural streets and observe whether a city’s spatial configuration (or structure) is related to outcomes of human behaviour and activity. In this case, the two previously unstudied outcomes were chosen: crime and traffic accidents. Taking an exploratory approach, Stockholm was chosen as the case study. Using the space syntax methodology, the street segments and natural streets connectivity was used to analyse whether accessibility or ‘potential through movement’ is associated with crime and traffic accidents. Two study areas were generated: a primary study area consisting of six nested zones and a secondary study area with hot spots and cold spots for events of crime and traffic accidents. To observe the statistical association between connectivity and events of crime and traffic accidents for natural streets and street segments, a classical regression model was used. The regression analysis showed that natural streets perform significantly better than street segments as they are better able to explain events of crime and traffic accidents. However, more so for traffic accidents. Most importantly, the topological structure or scaling characteristics of natural streets served as a better indicator for measuring human phenomena. The implication of this is that it could potentially be used to further the understanding of human activities in the context of the urban environment.

     

  • Fenske, James
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Retrofitting Accessibility in a Rapidly Expanding City: The Case of Bus Rapid Transit and Transit-Oriented Development in Dar es Salaam2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Urbanisation is a global trend, but in recent decades it has been occurring at particularly high rates in the Global South. Cities in Sub-Saharan Africa are facing a number of challenges as their populations grow, and among these, urban accessibility stands out as one of the most difficult to contend with. Meeting this challenge will require new solutions, and recently Bus Rapid Transit (BRT) and Transit-Oriented Development (TOD) have emerged as two potentially revolutionary innovations, especially when combined. In 2016, Dar es Salaam launched a BRT system, and in 2017 it introduced a TOD strategy in order to combat the city’s urban accessibility crisis. This study investigates the urban form at and around BRT stations in order to characterise BRT-TOD in the city and extract lessons for future implementations of BRT-TOD in Dar es Salaam and beyond. The investigation was carried out within the framework of urban morphology. It was found that at locations in the city centre, BRT has generally been able to integrate seamlessly into the built environment and achieve many of the core principles of TOD. In the rest of the city, however, BRT acts simply as a form of transit, with stations generally removed from the urban fabric and the local place. Some general issues are the large building setback, the number of informal vendors, private transport operators, exclusive new developments, lack of public spaces, the low quality of the pedestrian environment and the reinforcement of unsustainable forms of urban sprawl. This study aims to contribute to a growing discussion of sustainable urban accessibility solutions in the rapidly expanding cities of the Global South.

  • Bäckström, Klara
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Tensions and Synergies Between Tactical Urbanism and Social Sustainability: A Case Study of the Sunset Triangle Plaza2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    For the past several years, the term social sustainability has gained a strong foothold within urban studies and has become a pervasive and trendy term that seems to be on everyone’s lips. Public space is widely acknowledged as an important urban feature, often in association with the social sustainability. As cities around the world are experiencing rapid population growth, creating meaningful and enjoyable public spaces is more important than ever.

    The heightened interest in social sustainability, public spaces and placemaking (as a physical manifestation of social sustainability) has led to the emergence of several urban intervention movements, such as Tactical Urbanism. In 2012, for the first time in Los Angeles’ history, this tactic was used to transform a car trafficked street in Silver Lake into a pedestrian friendly public space: the Sunset Triangle Plaza. The aim of this thesis is to, by studying the use and function of the plaza after the conversion, highlight how a broad concept such as social sustainability can be understood from a relatively small-scale public space intervention.

    The case study was conducted during the spring and summer of 2018, using a variety of data sources including interviews and observations of the plaza during February and March 2018. Two interviews were conducted with managers of the businesses directly adjacent to the plaza. Moreover, street surveys were conducted on two different occasions to ask the public about their use and opinions about the plaza. The results from the case study are presented to illustrate the real-life experience of the theories about social sustainability, public space and a discussion regarding “Whose Public Space?”, when applied at a local context. The findings were then further divided into three categories: usage (what type of activities did the installation enable?), users (for whom were they enabled?) and change (indicators of how the site has changed), reflecting the notions of Tactical Urbanism.

    While certain changes have been merely “tactical”, others were more substantial; businesses flourished, traffic safety increased, the space has become a meeting place and therefore, it has now got an identity. Immediate change was evident in the process of the physical change when the plaza was constructed, but what has also followed is a continuous change. Even though the plaza with its painted dots may not look like much, a new space for engagement and interaction has been created, both physically and mentally. In addition, converting a street for the cars into a plaza dedicated to pedestrians is especially symbolic in a city like Los Angeles, where the automobile has been the predominant mean of transport for the last 60 years and instrumental in shaping the city’s layout. However, the case study also showed that it is one thing to launch a Tactical Urbanism initiative and another thing to maintain it and achieve long-term social changes.

    The examined concepts and models to evaluate whether a public space can be considered successful are not always useful. The Sunset Triangle Plaza has certainly changed, but it has implied a continuous change – for better and for worse. Thus, this study also shows that it is evident that the idea of the “organically emerged” city can imply both opportunities and limitations.

  • Ramasamy Venkatesamoorthy, Divya
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Manifestation of Urban Segregation in the Urban Form2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Segregation in urban areas is a universal phenomenon. A combination of factors include but are not limited to: city form, planning policies, policies relating to the settlement of immigrants, economic policies, building of infrastructure and chronological events in the growth of a city. Through this thesis work, I would like to examine how urban form is different in areas of the city where racial/ economic segregation is prevalent in Stockholm city. The hypothesis which I would like to examine through study is : The development and maintenance of urban form(which stands to denote all elements relating to the urban area: roads, pavements, lighting fixtures, buildings, public services etc) is influenced by segregation in the city, and it reflects and in turn reinforces the prevalent segregation.

  • Eduards, Rasmus
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Geoinformatik.
    Custom Base Maps for Utility Network Applications2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Web maps are today used more than ever. These are often displayed in geographical information system solutions. Web maps are often constructed in the terms of different layers where the bottom-most layer is called base map or background map. A specific kind of base maps are those that are the canvas for utility networks. These base maps can look vastly different from each other. Sometimes the base map can be overlooked. Currently there are different theories and opinions on how these base maps shall be designed and what information they shall contain. This thesis investigates a suitable base map design for utility network management and also creates some prototypes as a proof of concept. The thesis focus mostly on three factors, colour, information visualisation and symbology. This is investigated by using a user-centred design approach and comparing it to existing findings in literature and among map theories. The user-centred design process involves a case study performed with participants that work with utility networks in web map solutions. The research method is an iterative process where the participants are answering three quantitative surveys. The surveys includes prototypes which is refined for each step after analysing the participants answers. The thesis concludes that low saturated colours is good practise to enhance the network, this is both evident in literature as well as in the case study. Amount of lightness in the base map seem to be more of a opinionated matter and can highly differentiate depending on users device. Using hue is recommended to make borders between map elements more distinct. The base map shall only obtain the most relevant information and more specific information is recommended to be added through additional layers. Further studies need to be done in order to investigate the networks design and there is also a need to investigate how a map solution with several layers shall be design and how the relationships between those layers shall be constructed for utility network management

  • Alsaifi, Fadi
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Aging of FeCrAl Surface Coatings2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Thesis is about the aging of FECRAL surface coatings. In this thesis various substrates have been investigated such as 16 Mo3, 304, 347, Sanicro 31, 800HT, Nikrothal 80 and Kanthal APMT. These substrates have been coated with different FeCrAl alloys, using two different coating methods spraying with (High Velocity Air Force) and welding with (Metal Inert Gas).

    The purpose of coating is to achieve specific properties of the layer without affecting the original properties of the substrate. Therefore, it is important to investigate the boundary layer between these two different materials to observe how the interdiffusion of different substances such as Cr, Al, Fe and C is affected, which is the purpose of this project.

    The method used to investigate this purpose was to expose these combinations in different temperatures and in different environments for different time intervals. Then, using LOM, SEM and EDS analysis, the change that the boundary layers have undergone is examined. Some calculations in DICTRA have also been performed to see if it was possible to find any connection between experimental data and simulation results.

    The result showed carburization of FeCrAl-coatings on 16Mo3 substrates which can lead to deterioration of mechanical properties in the substrates but also decreased corrosion resistance for the coated layers. The result has also shown that it is difficult to perform spraying for small cylindrical products. The reason for this may be the high powder dispersion and the expansion of certain products when spraying, which causes the layer to loosen due to the shrinkage followed by cooling. APMT sprayed with Nikrothal 80 has shown high porosity in the substrates and high interdiffusion of Fe and Ni. High Ni diffusion in low Al alloys such as K 198 may be a reason why the coated layer cannot optimally form the protective oxide.

  • Londono Castrillon, Natalia Andrea
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.).
    A Topological analysis of an alternative to the PageRank algorithm in weighted directed graphs2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis I use seven data-sets of weighted, directed graphs and present them as weighted, directed k-simplicial complexes. Then, I analyse the topological properties of each data-set in question using Flagser by \cite{flagser} and the cluster at the TU Darmstadt. I then proceed to run two versions of an alternative to the PageRank algorithm. One version contracting and deleting every node visited, and the other deleting only those visited nodes with less than 3 neighbours. I record snapshots of how the data-sets throughout the run of the algorithm, and compute the same topological properties computed before the run. I compare the changes in their homology to understand how the algorithm alters the topology of the graph. I also run several runs of the algorithms to get an idea of how the average graph looks like after the algorithm has been run. I record their new topological properties to find a correlation between the performance of the algorithm and the change in the topology of the graphs.

  • Gomez-Torrent, Adrian
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    A Silicon Micromachined 220-330 GHz Turnstile Orthomode Transducer (OMT) in a Low-Loss Micromachining Fabrication Platform2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The work presented in this paper reports on the first wideband OMT in any frequency band implemented by micromachining. This turnstile-junction design provides full waveguide-band operation (220-330 GHz) and is the first implementation of a turnstile-OMT above 110 GHz, since very accurate fabrication is required for this topology. The measured insertion loss is below 0.5 dB and below 0.6 dB for the two polarizations, respectively, with an average measured return loss of 22 dB. Except for some spikes which still are below 30 dB, the cross-polarization is between 50 and 60 dB.

  • Shah, Umer
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    A Very High Isolation (>50 dB) and Low Insertion Loss (<0.55 dB) 140-220 GHz MEMSWaveguide Switch2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents for the first time a very high isolation, low insertion loss MEMS waveguide single-pole singlethrow(SPST) switch operating in the 140-220 GHz frequency band. The high isolation is achieved by stacking threeMEMS chips, two of which contains MEMS-reconfigurable surface to block/unblock the signal in the waveguide. Thisdoubles the isolation and has little impact on the insertion loss and virtually no influence on the bandwidth. Themeasurement results of the prototype switch shows 50 to 60 dB isolation in the blocking state and 0.40 to 0.55 dBinsertion loss in the non-blocking state for the whole waveguide band. Additional measurements with reference chipshave shown that the MEMS reconfigurable surfaces of the two switch chips together contribute only to 0.1 to 0.3 dBinsertion loss. The switch bandwidth is limited only by the waveguide cut-off and not by the switch technology itself.

  • Shah, Umer
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Gomez Torrent, Adrian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Mikro- och nanosystemteknik.
    Ultra-Compact Micromachined Beam-Steering Antenna Front-End for High-Resolution Sub-Terahertz Radar2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper reports on an ultra-compact sub-THz frequency based beam-steering radar antenna front-end implementation utilizing a micromachined parallel-plate waveguide based leaky wave antenna. At a size of only 24 × 24 × 0.9 mm 3 , the beam-steering front-end antenna has a 28 dBi gain and a 45° field of view for scanning over 220-300 GHz. As compared to a theoretical range resolution of 6.8 mm, a range resolution of 1.2 cm was experimentally verified for 2.5 cm large targets separated by 8°. Furthermore, this paper shows a signal processing technique for frequency-steerable antennas which achieves high angular target separation by splitting the measurement frequency range into sub-sections to isolate similar slant range close-proximity targets into different frequency spaces.

  • Legeby, Ann
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur, Stadsbyggnad.
    Kan utvecklingen av det urbana öka mångfalden av livsmiljöer?2019Inngår i: Rurban Planning Talks / [ed] Nils Björling, Mariestad: DaCapo Mariestad , 2019, s. 24-27Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Rurban Planning Talkds är en dialog mellan akademi och planeringspraktik för att klargöra de problem som pågående urbana och regionala omvandlingar medför. Vi vill utveckla och diskutera de samhällsutmaningar, konflikter och möjligheter som uppstår i skärningspunkten mellan landsbygd och stad. Fokus är alla de kommuner som rymmer både landsbygder och städer, och deras gemensamma arbete för hållbar utveckling. 

  • Gustavsson, Hanna
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Clustering Based Outlier Detection for Improved Situation Awareness within Air Traffic Control2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this thesis is to examine clustering based outlier detection algorithms on their ability to detect abnormal events in flight traffic. A nominal model is trained on a data-set containing only flights which are labeled as normal. A detection scoring function based on the nominal model is used to decide if a new and in forehand unseen data-point behaves like the nominal model or not. Due to the unknown structure of the data-set three different clustering algorithms are examined for training the nominal model, K-means, Gaussian Mixture Model and Spectral Clustering. Depending on the nominal model different methods to obtain a detection scoring is used, such as metric distance, probability and OneClass Support Vector Machine.

    This thesis concludes that a clustering based outlier detection algorithm is feasible for detecting abnormal events in flight traffic. The best performance was obtained by using Spectral Clustering combined with a Oneclass Support Vector Machine. The accuracy on the test data-set was 95.8%. The algorithm managed to correctly classify 89.4% of the datapoints labeled as abnormal and correctly classified 96.2% of the datapoints labeled as normal.

  • Yu, Xingjiang
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    OSM-Based Automatic Road Network Geometries Generation on Unity2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays, while 3D city reconstruction has been widely used in important topics like urban design and traffic simulation, frameworks to efficiently model large-scale road network based on data from the real world are of high interests. However, the diversity of the form of road networks is still a challenge for automatic reconstruction, and the information extracted from input data can highly determine the final effect to display.

    In this project, OpenStreetMap data is chosen as the only input of a three-stage method to efficiently generate a geometric model of the associated road network in varied forms. The method is applied to datasets from cities in the real world of different scales, rendered and presented the generated models on Unity3D platform, and compared them with the original road networks in both the quality and topology aspects. The results suggest that our method can reconstruct the features of original road networks in common cases such as three-way, four-way intersections, and roundabouts while consuming much shorter time than manual modeling in a large-scale urban scene. This framework contributes to an auxiliary tool for quick city traffic system reconstruction of multiple purposes, while there still being space of improvement for the modeling universality and quality of the method.

  • Mallor, Fermin
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Enabling high-fidelity measurements of turbulent boundary layer flow over wing sections in the MTL wind tunnel.2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A reinforced fiber-glass model of a NACA 4412 wing profile is designed and set-up in the Minimum Turbulence Level (MTL) wind tunnel facility at KTH. The model has 65 pressure taps orifices, and the set-up includes two mounting panels designed to allow for particle image velocimetry (PIV) and hot wire anemometry (HWA) measurements of the boundary layer (to be performed in a future campaign). In a first experimental campaign pressure scans are conducted at three angles of attack of interest (5,10 and 12 degrees), and at four different Reynolds numbers based on chord length and inflow velocity (200,000, 400,000, 1,000,000, and 1,640,000). The preliminary results show good agreement with DNS and LES data, however, the effective angle of attack of the wing is affected by the interference of the test section. In order to obtain proper flow conditions for future campaigns inside the test section, wall inserts are designed using 2D k-omega SST simulations. The side-walls are streamlined and the final geometry is corrected to account for the boundary-layer growth over them. The inserts are shown to avoid early separation near the trailing edge at higher angles of attack (10 and 12 degrees), but the 2D simulations fail to capture the aforementioned angle-of-attack issue affecting the pressure distributions. Future extensions of the present insert design should include both 3D simulations of the test-section and a robust optimization procedure to prescribe the resulting pressure distribution.