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  • Englesson, Erik
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Azizpour, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Efficient Evaluation-Time Uncertainty Estimation by Improved Distillation2019Konferansepaper (Fagfellevurdert)
  • Baldassarre, Federico
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Azizpour, Hossein
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Explainability Techniques for Graph Convolutional Networks2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Graph Networks are used to make decisions in potentially complex scenarios but it is usually not obvious how or why they made them. In this work, we study the explainability of Graph Network decisions using two main classes of techniques, gradient-based and decomposition-based, on a toy dataset and a chemistry task. Our study sets the ground for future development as well as application to real-world problems.

  • Kouach, Mona
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Hållfasthetslära (Avd.).
    Methods for modelling lattice structures2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The application of lattice structures have become increasingly popular as additive manufacturing (AM) opens up the possibility to manufacture complex configurations. However, modelling such structures can be computationally expensive. The following thesis has been conducted in order for the department of Structural Analysis, at SAAB in Järfälla, to converge with the future use of AM and lattice structures. An approach to model lattice structures using homogenization is presented where three similar methods involving representative volume element (RVE) have been developed and evaluated. The stiffness matrices, of the RVEs, for different sizes of lattice structures, comprising of BCC strut-based units, have been obtained. The stiffness matrices were compared and analysed on a larger solid structure in order to see the deformational predictability of a lattice-based structure of the same size. The results showed that all methods were good approximations with slight differences in terms of boundary conditions (BCs) at the outer edge. The comparative analyses showed that two of the three methods matches the deformational predictability. The BCs in all methods have different influences which makes it pivotal to establish the BCs of the structure before using the approach presented in this thesis.

  • Rudd, Clive
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Energialstring för drivande av smart enhet utan batterier: Design av ett energialstrande system för smart sko genom piezoelektronik och solceller2019Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Projektet beskriver ett tillvägagångssätt för att alstra energi genom solceller och piezoelektronik. Ett kretskortsbaserat system designades som utnyttjade superkondensatorer som lagringsenhet. Planen var att integrera systemet i en sko. Genom denna teknik kan man då substituera eller minimera batteriladdningen för smarta enheter eller mindre anordningar. Det önskvärda resultatet med projektet var att se om det gick att koppla detta system till en mikrokontroller som kunde drivas på låg spänning. Rapporten fick ett positivt resultat med en konstant utspänning på 1.8 volt som kunde driva en mikrokontroller. Dock tog det lång tid för superkondensatorerna att laddas upp på grund av den impedans som fanns i systemet. Aktiviteter som utnyttjar detta system kommer att påverka uppladdningens resultat. Detta gör kretsen optimal för aktiviteter som involverar rörelse och sol, såsom hiking.

  • Thölberg, Anton
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Grönblått Stockholm: Förutsättningar för klimatsmarta snötippningsplatser2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Klimatforskare världen över är i stort sett eniga om att mänskliga aktiviteter påverkar de pågåendeklimatförändringarna. Sett ur ett globalt perspektiv fortsätter många länder att släppa ut stora mängder växthusgaser och enligt flera studier förväntas konsekvenserna av utsläppen verka långt in i framtiden, även om den globala temperaturhöjningen hålls under två grader. För Stockholmsregionen har analyser av väderdata kunnat konstatera att somrarna har blivit varmare och vintrarna mer snöfattiga, med mer nederbörd som faller som regn. Framöver förväntas även fler fall av värmeböljor och skyfall inträffa, vilket kommer att resultera i nya hållbarhetsutmaningar för Stockholm. Forskning och praktik visar att grön-blå infrastruktur kan mildra effekterna av nuvarande och kommande klimatförändringar genom nyttjande av ekosystemtjänster, t.ex. genomgrönska i dagvattensystem och stadsträd.

    Syftet med denna studie har varit att ta fram ett kunskapsunderlag för hur gröna- och blå strukturer kan integreras i den bebyggda miljön för att stödja Stockholms stad i det pågående klimatanpassningsarbetet. Arbetet tar utgångspunkt i ett pilotprojekt framtaget av Trafikkontoret i Stockholm, inom vilket ytor har identifierats för snöupplag i stadsdelsområdena Bromma och Spånga-Tensta. Utifrån resultatet från detta projekt har sedan en kvalitativ utvärdering gjorts gällande två utpekade platsers potential att kunna leverera multipla funktioner för att kunna hantera nuvarande och kommande temperatur- och nederbördsmönster. De metoder som har använts i detta arbete är en litteraturstudie och en fallstudie.

    Studien visar att det i arbetet med att främja grön-blå infrastruktur är möjligt att generera mångfunktionella ytor som kan bidra till både temperaturreglering och översvämningshantering. Resultaten från fallstudien visade att de utvalda lokaliseringsförslagen hade olika förutsättningar för att kunna fungera som snödeponi samt verka främjande för temperaturreglering och översvämningshantering. Data för strålningstemperatur och skyfall indikerade även att platserna riskeras att utsättas för stark värme och fler översvämningar framöver, vilket till viss del antas bero på en begränsad mängd vegetation. Konsekvenserna av resultaten antydde också att det för stadsplanering och klimatanpassning generellt finns ett behov av att planera för mångfunktionella lösningar i takt med att staden växer och förtätas. En startpunkt för detta är att ta bättre vara på naturen och dess utbud i syfte att kunna tillhandahålla ett lokalklimat inom vilket människan och annat liv kan leva och frodas i, även i tider av förändring.

  • Vlassopoulou, Efstathia
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Urban form and sustainability: Comparison between low-rise “garden cities” and  high-rise “compact cities” of suburban areas2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Urbanization and climate change are two of the most important issues of our days. Many attempts have been made to define the most sustainable way to organise cities in order to cope with the increased population, while simultaneously being climate friendly, socially acceptable and economically viable. This master thesis focuses on the comparison of the sustainability performance of two particular theoretically planned urban forms, located in the suburban area of Stockholm – a “compact city”-like neighborhood and a “garden-city”-like neighbourhood. It was decided that the focus would be on the carbon footprint of the representative residences of each urban form, with the help of Life Cycle Assessment (LCA); and that overall sustainability criteria for neighbourhoods would after wards be assessed, having a certification system forsustainable neighbourhoods (CityLab for districts, in particular) as a framework for a – mostly theoreticalassessment. After the exploring of the differences in the sustainability performance(environmental and social) of the two assessed urban forms, a discussion is made concerning the relationship between urban form and sustainability and conditions under which the most sustainable urban form could be achieved. The results of the analysis highlight that the concept “one size fits all” cannot conform to urban planning decisions, since cities should be able to adjust to the needs of each generation.

  • Salazar Ruiz Velasco, Maria Fernanda
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Food Waste Management in a Circular Economy Perspective: A case study of Swedish juice plant Loviseberg presseri AB2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    One third of all the food produced for human consumption is being wasted all around the world. The recovery and optimum use of this food waste is vital to support the growing population and food demand. The main objective of this research is to identify the optimum use of organic waste, using a circular economy approach, to generate recommendations that help industries in the food sector to reduce and valorize waste.

    A case study for food waste management alternative selection with the Swedish juice plant Loviseberg presseri AB is presented. This study furthermore proposes a detailed operation procedure of the selected options according to the results exploring the potential add value to the residue remaining from cold-pressed juice process. It was found that 49% of the total weight from raw material is wasted after the extraction process, being apple and orange the larger contributors.

    The research identified and recommended, for the specific case study, that the optimum use of apple pomace is used for ingredient for human consumption products, followed by animal feed and pectin production. As for the orange waste, it was identified to be used for essential oil extraction, followed by animal feed and anaerobic digestion. Furthermore, the results of the research shows, that a combination of the different waste management alternatives would also benefit the company. The research also identified potential challenges as well as benefits, which depend in the specific waste analyzed.

  • Jazzar, Jacques
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Methods of post-treatment of aerodynamic tests of engine boosters2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Aerodynamics studies in a booster such as analysis of the flow through the whole component or study of local turbulent phenomenon constitute a crucial part of its development in order to get better overall performances, like efficiency of the compressor and compression ratio. In order to put in perspective the computational predictions, it is critical to obtain sets of data from tests to caliber numerical analyses and to assure the booster respects design specifications. Aerodynamics testing is then an important part of the development of a compressor. However, it is complicated to obtain such values for many reasons: time constraints, problems regarding support, important costs etc. Thus, it is important to get as much information as possible from these tests data in a limited period in order to spend more time in results interpretation and less in treating raw data. Thus, an optimized tool of treatment to first deduce results from test data; and then to compare different engines or different sets of tests data, to get a wider state of the art and to avoid time-consuming analyses was needed. In order to do so, the first part of the development consists in investigating the existing methods to extract and analyze data from tests already used, and then deducing a general methodology to obtain from raw measures the performances of the studied booster compared to other available data. Once the methods have been set up and validated, the tool in itself was implemented in a practical way. Then, it was important to validate it on real tests values and to observe if it was adjustable for all kind of aerodynamics tests.

  • Johnson, Emelie
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Per- and Polyfluoroalkyl Substances (PFASs) Removal from Landfill Leachate: Efficiency Evaluation in Column Experiments2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Per- and polyfluoroalkyl substances (PFASs) are known for their wide spread in the environment, their persistent properties and their ability of biomagnification through the food chain. With properties such as oil and water repellence, temperature resistance and a long lifespan they have been frequently used in various areas, e.g. hygiene products such as shampoo and tooth paste as well as in the firefighting industry as firefighting foam. They are therefore commonly found in leachate from landfills. Up to now, there is a lack of studies investigating methods of how to treat PFAS-contaminated leachate and hence more research in this area and development of suitable treatment technologies is needed.

    In this study, column experiments with granulated activated carbon (GAC), anion exchanger (AE) resin and peat mixed with ash were performed. The results showed that AE removed PFAS more efficiently than GAC, that longer chains had a higher sorption ability than shorter chains and that perfluorinated sulfonic acids (PFSAs) a higher sorption ability than perfluorinated carboxylic acids (PFCAs). The peat-ash columns had a slower flow and only 5bed volumes (BVs) of leachate were treated. Hence, these results could not be compared with GAC and AE. For GAC and AE 1920 BVs and 1840 BVs, respectively, were treated and none of the filters got fully saturated. The conclusion of the study is that AE is likely a more suitable treatment technology for this purpose than GAC but more research is needed to determine the breakthrough and design PFAS treatment for leachate.

  • Janoco, Martin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Evaluating the sustainability of vegetarian, vegan, and New Nordic diets in Sweden: Combining environmental and nutritional aspects2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Changing the western dietary pattern toward a healthier diet with reduced intake of animal foods is a commonly recognized strategy in the ongoing effort for global sustainability. Since animal foods tend to have a high environmental impact, vegetarian diets are often suggested as an ecological alternative to the typical Western diet. The low sum of environmental impacts, however, does not on its own necessarily translate to a sustainable diet. Sustainability encompasses many other aspects, such as nutritional adequacy, affordability, and cultural acceptability. As regards the elimination of animal foods in particular, health-related aspects ought to be considered since some nutrients are supplied primarily via animal products which may lead to nutritional deficiencies and potential negative health effects in the long term. Furthermore, since the main function of diets is the supply of (adequate) nutrition, the environmental impacts of diets ought to be compared in light of their nutritional quality. In this project the environmental impact on climate change, land use, blue water footprint, and biodiversity damage potential of four diets is assessed, along with their nutritional adequacy and financial cost. The four assessed diets are: an average Swedish diet, New Nordic diet, vegetarian diet, and vegan diet. The environmental impacts are normalized with a nutritient-rich diet score (NRD) to compare the impacts of diets in relation to their nutritional quality. The vegan diet, followed by the vegetarian diet, resulted in the lowest overall impact with the exception of blue water footprint, however, the normalization with NRD score lessened the relative differences between the New Nordic, vegetarian, and vegan diet. Furthermore, the nutritional assessment showed a potentially unsustainable intake of vitamin D in vegetarians and vit. D and B12 in vegans, which is not properly reflected in the nutritional quality score. Nevertheless, the use of the nutritional score is fairly simple and provides opportunity for linking the health-related aspect of diets to their environmental impact. Joined with indicators on other sustainability aspects, such as the economic, this method can offer a more holistic picture of the sustainability of diets.

  • Dubrova, Elena
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Näslund, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Degen, Bernhard
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Gawell, Anders
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Yu, Yang
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    CRC-PUF: A Machine Learning Attack Resistant Lightweight PUF Construction2019Inngår i: 2019 IEEE European Symposium on Security and Privacy Workshops (EuroS&PW), IEEE conference proceedings, 2019, s. 264-271-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Adversarial machine learning is an emerging threat to security of Machine Learning (ML)-based systems. However, we can potentially use it as a weapon against ML-based attacks. In this paper, we focus on protecting Physical Unclonable Functions (PUFs) against ML-based modeling attacks. PUFs are an important cryptographic primitive for secret key generation and challenge-response authentication. However, none of the existing PUF constructions are both ML attack resistant and sufficiently lightweight to fit low-end embedded devices. We present a lightweight PUF construction, CRC-PUF, in which input challenges are de-synchronized from output responses to make a PUF model difficult to learn. The de-synchronization is done by an input transformation based on a Cyclic Redundancy Check (CRC). By changing the CRC generator polynomial for each new response, we assure that success probability of recovering the transformed

  • Kajita, Heidi Svenningsen
    et al.
    kajita, masashi
    Material Includes2017Bok (Annet vitenskapelig)
  • Chyad, Yousif
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Ali, Khadija
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Logistik vid begränsat utrymme: Jämförelsestudie mellan fyra byggarbetsplatser2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Planning of material handling in limited spaces has become more relevant in the construction industry and since material cannot always be delivered at the right time in the right place, a delay in the flow chain is created. Each construction site has unique conditions and thus different solutions.In this thesis, four workplaces at Peab have been visited and inspected. The purpose of the thesis was to explore the problems that arise with the logistics in a limited space and find solutions that can be implemented on future construction projects.The aim of the study was to find the common factors that exist for the workplaces within a small area and find ways of working that can change the planning and execution of logistics.Surveys to professional workers and interviews with site managers and supervisors contributed with information to the report.After compiling the thesis work, the result shows that there are opportunities to change the working method of the work management to increase efficiency and productivity.In the study, it appears that there is a lack of communication in the workplaces as a large number of workers do not know when the next delivery of material takes place. In addition, the professional workers admit that they did not have a great influence over the business. Recommended solutions that were developed in the study were experience feedback and further development of the APD plan.

  • Disputas: 2019-10-22 13:15 Seminar room, Dept. of Solid Mechanics, Stockholm
    Brandberg, August
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Insights in paper and paperboard performance by fiber network micromechanics2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Fiber networks are ubiquitous due to their low cost and high ratio of mechanical performance to weight. Fiber networks made of cellulose fibers from trees are used as information carriers (paper) and as packaging (board). Often the ideal product is both mechanically sturdy and possible to print on. This thesis investigates the underlying reasons for the mechanical performance of paper and board through the discretization and direct simulation of every fiber in the network.

    In Paper A the effect of fiber-fiber bond geometry on sheet stiffness is investigated. Many packaging products seek to maximize the bending stiffness by employing stiff outer layers and a bulkier layer in the middle. In bulky sheets, the fibers are frequently uncollapsed resulting in a more compliant bonded segment. Because all the loads in the network are transferred via the bonds, such compliance can cause unexpectedly large decreases in mechanical performance. Although many models have been presented which aim to predict the tensile stiffness of a sheet, these predictions tend to overestimate the resulting stiffness. One reason is that the bonds are generally considered rigid. By finite element simulations, we demonstrated the effect of the lumina configuration on the stiffness of the bonded segment on the scale of single fiber-to-fiber bonds, and that the average state of the fiber lumen has a marked effect on the macroscopic response of fiber networks when the network is bulky, has few bonds, or has a low grammage.

    Compression strength is central in many industrial applications. In paper B we recreated the short span compression test in a simulation setting. The networks considered are fully three-dimensional and have a grammage of 80 to 400 gsm, which is the industrially relevant range. By modeling compression strength at the level of individual fibers and bonds, we showed that fiber level buckling or bifurcation phenomena are unlikely to appear at the loads at which the macroscopic sheet fails.

    In paper C, we developed a micromechanical model to study the creation of curl in paper sheets subjected to a moisture gradient through the sheet. A moisture gradient is always created during the printing process, which may lead to out-of-plane dimensional instability. We showed that the swelling anisotropy of individual fibers bonded at non-parallel angles causes an additional contribution to the curl observed on the sheet level.

  • Möller, Anton
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Piezoelectric tuning of integrated photonic delay circuits2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • Shokri-Ghadikolaei, Hossein
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Ghauch, Hadi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik. COMELEC Department, Telecom ParisTech, Paris, France.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Skoglund, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Learning and Data Selection in Big Datasets2019Inngår i: Proceedings of the 36th International Conference on MachineLearning, Long Beach, California, PMLR 97, 2019., 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Finding a dataset of minimal cardinality to characterize the optimal parameters of a model is of paramount importance in machine learning and distributed optimization over a network. This paper investigates the compressibility of large datasets. More specifically, we propose a framework that jointly learns the input-output mapping as well as the most representative samples of the dataset (sufficient dataset). Our analytical results show that the cardinality of the sufficient dataset increases sub-linearly with respect to the original dataset size. Numerical evaluations of real datasets reveal a large compressibility, up to 95%, without a noticeable drop in the learnability performance, measured by the generalization error.

  • Stigsson, Martin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Ivars, Diego Mas
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Selroos, Jan-Olof
    SKB, Swedish Nuclear Fuel and Waste Management Co.
    A method to estimate flow and transport properties of sheared synthetic fractures in crystalline rock with different roughness under varying normal stressManuskript (preprint) (Annet vitenskapelig)
  • Stigsson, Martin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Johansson, Fredrik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Some aspects on the applicability of peak shear strength criteriaManuskript (preprint) (Annet vitenskapelig)
  • Grinbergs, Lauris
    et al.
    Höglund, Ingemar
    Ottoson, Göran
    Åtgärder för förbättrad mögelresistens hos beklädnader i våtrum1995Rapport (Annet vitenskapelig)
    Abstract [sv]

    Val av beklädnader i våtrum är viktigt, då hårda krav ställs på dem:

    hög luftfuktighet, vattenspolning och mekanisk nötning (skrapning). De måste vara lätta att rengöra och får inte medverka till mögelbildning. Laboratorieförsök utfördes i speciellt uppbyggda duschkabiner i full skala och under verklighetstrogna förutsättningar. Under två faser, I och Il, studerades hur åtta genuina våtrumssvampar utvecklats och angripit ytskikt vid varierande villkor avseende luftfuktighet, fritt vatten, näringstillgång och mögelsporbildning. Parallellt med kabinförsöken i fas I bestämdes också mögelresistensen i en serie med mindre provplattor, s k "panel-tests".

    Även "case-studies" av mögelpåväxt i våtrum i praktiken ingick. Rapporten redogör detaljerat för objekt, näringssubstrat, våtrumssvampar, antal kolonier, påväxtgrad, pH-värden etc samt praktiska konsekvenser.

  • Grinbergs, Lauris
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE).
    Mögelresistens hos beklädnader i våtrum1992Rapport (Annet vitenskapelig)
    Abstract [sv]

    Bakgrunden till undersökningen är i korthet att våtrummen i det svenska bostadsbeståndet under senare tid utsatts för omfattande mögelangrepp. Detta innebär förutom dyrbara skadeavhjälpande åtgärder av byggnadsteknisk art att mykologisk bekämpning också måste till i någon form. Mögel innebär för de boendes del en väsentlig sanitär olägenhet.

    Projektet "Mögelresistens hos beklädnader i våtrum" har huvudsakligen omfattat experimentella byggnadstekniska och mykologiska undersökningar, vilka indelats i tre skilda faser. Under de tvi första faserna har studerats hur genuina våtrumssvampar utvecklats och angripit ytskikt vid varierande randvillkor avseende luftfuktighet, fritt vatten, näringstillgång och mögelsporbildning . I en tredje och avslutande fas har studerats hur effektiva några vanliga saneringsmedel för hushållsändamål är.

    Tre huvudgrupper av beklädnadssystem har undersökts

    * färgsystem med plast som bindemedel i allmänhet på bärare av glasfiberväv. Plasterna har i ytskikten utgjorts av PVA-latex, akrylatlatex, akrylatsampolymerlatex och alkydlack

    * plasttapeter, väggmattor av plast samt plastlaminat. Plastmaterialet i ytskikten har utgjorts av PVC resp melaminformaldehydharts. keramiska plattor, klinker och kakel.

    * Plasttapeter, väggmattor av plast samt plastlaminat. Plastmaterialet i ytskikten har utgjorts av PVC resp melaminformaldehydharts. keramiska plattor, klinker och kakel.

     

    Vid försöken har utnyttjats speciellt uppbyggda kabiner (duschkabiner), för att kunna genomföra de olika undersökningarna i full skala och under så verklighetstrogna förutsättningar som möjligt . För att också kunna göra säkrare jämförelser mellan undersökta beklädnadssystem har även en kontrollserie ingått, där samma beklädnad som i kabinerna utsatts för mögelangrepp. Ett stort antal, 48 st för varje beklädnadssystem och totalt ca 400 st, mindre provplattor har inokulerats med mögelsporer underlag av olika näringssubstrat.

    Nya begrepp som mögelpåväxtgrad och skadegrad (skala 0-5) har använts vid bedömningen av beklädnadssystemen.

  • Zou, Liangchao
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Jing, Lanru
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Ivars, Diego Mas
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Impact of Normal Stress Caused Closure on Fluid Flow and Solute Retention in Rock Fractures2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modeling of coupled hydro-mechanical and chemical (HMC) processes in fractured rocks is an important topic for many geoengineering projects.  Over the past decades, many efforts have been devoted to study the flow and transport in single fractures with consideration of mechanical effects. It is generally known that the mechanical effects, i.e. normal and shear deformation, significantly affect fluid flow and solute transport processes in rough-walled rock fractures since the deformation may largely alter the structure of fracture apertures that directly controls transmissivity. Due to complicated physical processes combined with complexity of geometry structures, many issues remain open questions, such as fracture surface roughness characterization, deformation dependence of transmissivity and advective transport in natural rock fractures. In this work, we attempt to investigate the impact of stress caused closure on fluid flow and solute advective transport in a rough-walled fracture through numerical modeling.  A rough-walled fracture model is created based on a laser-scanned rock surface. The Bandis’s model is used to describe the fracture closure subject to normal stress. The flow is modeled by solving Reynolds equation and the advective transport is simulated through Lagrangian particle tracking. The results show that the normal stress caused fracture closure creates asperity contacts and reduces the mean aperture, which significantly reduces transmissivity, and affects the travel time and transport resistance. With increases of normal stress, the specific surface area reduces nonlinearly due to the nonlinear closure. In practice, especially for important hydrogeological projects, e.g. nuclear waste disposal, it is important to consider the coupled HMC processes in design and risk assessment.

  • de Alwis, Pahansen
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Garme, Karl
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Monitoring and characterization of vibration and shock conditions aboard high-performance marine craft2018Inngår i: Journal of Engineering for the Maritime Environment (Part M), ISSN 1475-0902, E-ISSN 2041-3084, Vol. 233, nr 4, s. 1068-1081Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The stochastic environmental conditions together with craft design and operational characteristics make it difficult to predict the vibration environments aboard high-performance marine craft, particularly the risk of impact acceleration events and the shock component of the exposure often being associated with structural failure and human injuries. The different timescales and the magnitudes involved complicate the real-time analysis of vibration and shock conditions aboard these craft. The article introduces a new measure, severity index, indicating the risk of severe impact acceleration, and proposes a method for real-time feedback on the severity of impact exposure together with accumulated vibration exposure. The method analyzes the immediate 60s of vibration exposure history and computes the severity of impact exposure as for the present state based on severity index. The severity index probes the characteristic of the present acceleration stochastic process, that is, the risk of an upcoming heavy impact, and serves as an alert to the crew. The accumulated vibration exposure, important for mapping and logging the crew exposure, is determined by the ISO 2631:1997 vibration dose value. The severity due to the impact and accumulated vibration exposure is communicated to the crew every second as a color-coded indicator: green, yellow and red, representing low, medium and high, based on defined impact and dose limits. The severity index and feedback method are developed and validated by a data set of 27 three-hour simulations of a planning craft in irregular waves and verified for its feasibility in real-world applications by full-scale acceleration data recorded aboard high-speed planing craft in operation.

  • Brandberg, August
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Kulachenko, Artem
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    The effect of geometry changes on the mechanical stiffness of fibre-fibre bonds2017Inngår i: Advances in Pulp and Paper Research, Manchester, 2017, s. 683-719Konferansepaper (Fagfellevurdert)
  • Dewulf, Art
    et al.
    Karpouzoglou, Timos
    Filosofi och historia, KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Filosofi och teknikhistoria, Historiska studier av teknik, vetenskap och miljö.
    Warner, Jeroen
    Wesselink, Anna
    Mao, Feng
    Vos, Jeroen
    Tamas, Peter
    Groot, Annemarie E.
    Heijmans, Annelies
    Ahmed, Farhana
    Hoang, Long
    Vij, Sumit
    Buytaert, Wouter
    The power to define resilience in social–hydrological systems: Toward a power-sensitive resilience framework2019Inngår i: WIREs Water, ISSN 0935-879X, E-ISSN 2049-1948, artikkel-id e1377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract Since the early work on defining and analyzing resilience in domains such as engineering, ecology and psychology, the concept has gained significant traction in many fields of research and practice. It has also become a very powerful justification for various policy goals in the water sector, evident in terms like flood resilience, river resilience, and water resilience. At the same time, a substantial body of literature has developed that questions the resilience concept's systems ontology, natural science roots and alleged conservatism, and criticizes resilience thinking for not addressing power issues. In this study, we review these critiques with the aim to develop a framework for power-sensitive resilience analysis. We build on the three faces of power to conceptualize the power to define resilience. We structure our discussion of the relevant literature into five questions that need to be reflected upon when applying the resilience concept to social?hydrological systems. These questions address: (a) resilience of what, (b) resilience at what scale, (c) resilience to what, (d) resilience for what purpose, and (e) resilience for whom; and the implications of the political choices involved in defining these parameters for resilience building or analysis. Explicitly considering these questions enables making political choices explicit in order to support negotiation or contestation on how resilience is defined and used. This article is categorized under: Human Water > Water Governance. Engineering Water > Planning Water.

  • Ghafoory, Jones
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Numerisk analys, NA.
    p-Laplacian Spectral Clustering Applied in Software Testing2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Software testing plays a vital role in the software development life cycle. Having a more accurate and cost-efficient testing process is still demanded in the industry. Thus, test optimization becomes an important topic in both state of the art and state of the practice. Software testing today can be performed manually, automatically or semi-automatically. A manual test procedure is still popular for testing for instance in safety critical systems. For testing a software product manually, we need to create a set of manual test case specifications. The number of required test cases for testing a product is dependent on the product size, complexity, the company policies, etc. Moreover, generating and executing test cases manually is a time and resource consuming process. Therefore, ranking the test cases for execution can help us reduce the testing cost and also release the product faster to the market. In order to rank test cases for execution, we need to distinguish test cases from each other. In other words, the properties of each test case should be detected in advance. Requirement coverage is detected as a critical criterion for test cases optimization. In this thesis we propose an approach based on a $p$-Laplacian Spectral Clustering for detecting the traceability matrix between manual test cases and the requirements, in order to find the requirement coverage for the test cases. However, the feasibility of the proposed approach is studied by an empirical evaluation which has been performed on a railway use-case at Bombardier Transportation in Sweden. Through the experiments performed using our proposed method it was able to achieve an $F_1$-score up to $4.4\%$. Although the proposed approach under-performed for this specific problem compared to previous studies, it was possible to get some insights on what limitations $p$-Laplacian Spectral Clustering have and how it could potentially be modified for similar kind of problems.

  • Mätzke, Margitta
    et al.
    Johannes Kepler University, Inst of Politics and Social Policy.
    Anttonen, Anneli
    University of Tampere, Faculty of Social Sciences.
    Brokking, Peter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Javornik, Jana
    University of East London, Sociology and Social Policy.
    Public Policy Conceptions: Priorities of Social Service Provision in Europe2017Inngår i: Social Services Disrupted: Changes, Challenges and Policy Implications for Europe in Times of Austerity / [ed] Flavia Martinelli, Anneli Anttonen and Margitta Mätzke, Cheltenham: Edward Elgar Publishing, 2017, s. 71-91Kapittel i bok, del av antologi (Fagfellevurdert)
  • Carrion Domenech, Luis Enrique
    KTH, Skolan för industriell teknik och management (ITM).
    Study of high flash point ethyl alcohol-based secondary fluids applied in Ground Source Heat Pumps systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Ethyl alcohol (ethanol) as secondary fluids is very popular as heat transfer fluid for indirect refrigeration system with ground source heat pump systems (GSHP) in several countries such as Sweden, Norway, Switzerland, Finland and other European countries. There have been several researches about the future ofthe refrigeration sector, refrigerants and refrigeration systems. Moreover, strict regulations such as F-gasregulation and Kigali Amendment forcing a phase down of many current widely used high global warming potential (GWP) refrigerants, i.e. R134a or R410A. Therefore, secondary refrigeration systems and their working fluids are expected to play a key role in order to minimize the refrigerant charge in the systems, reduce the indirect refrigerant leakages as well as increase the safety during operation.

    The aim of this thesis is to investigate the effect different additives to increase the flame point together with ethanol-based secondary fluids and validate their thermophysical properties by comparing them with reference values for pure ethanol water solutions. The study aims to design a new commercial ethyl alcohol-based product for GSHP system that could replace existing ones in the Swedish market and could workwith natural or flammable low GWP refrigerants.

    Different high flash point additives were tested such as 1-propyl alcohol, n-butyl alcohol, glycerol andpropylene carbonate. Thermophysical properties were investigated and a GSHP model in Excel was created in order to assess the energy performance of the resulted blends.

    After screening different blends and assessing the energy performance, glycerol as additive in low concentration seems to be the future for the ethyl alcohol-based secondary fluids because of its high flashpoint (160ºC) that will reduce the flammability risk associated to ethyl alcohol blends, the low viscosity (by 12% lower compared to pure ethyl alcohol blends) that help reduce pumping power by 4.5% compared topure ethyl alcohol blends. Moreover, ethyl alcohol and glycerol blend showed the lost in heat transfer coefficient by 4% lower compared to pure ethyl alcohol blends due to lower thermal conductivity compared to pure ethyl alcohol blends. Finally, it is a rather cheap and natural product which has no problem related to corrosion since ethyl alcohol and glycerol are less corrosive than water.

    Although, flash point test was not conducted so there is no data regarding the flash point, it is expected the flash point is increased due to the high flash point of glycerol compared to ethyl alcohol or other possible additives. Therefore, it is expected that the flammability risk associated to ethyl alcohol-based secondary fluids is reduced.

  • Mekler, Sandra
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Alfredo, Ambre
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    The construction of identity: An urban study of the Centrums of Rinkeby, Tensta and Husby2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The Stockholm Municipality has set inclusion at the core of its objectives for the city with its “Vision 2040: A Stockholm for Everyone” (Stockholm Stad, 2018). Acknowledging the divide between neighborhoods, the government has brought forward social sustainability as a key component to improve the fast-growing city. This research focuses on three of the most stigmatized neighborhoods of Stockholm: Rinkeby, Tensta, and Husby, where residents are predominantly of foreign background, to offer an alternative way of understanding inclusion. Specifically, this study looks into the public spaces at the center of these three neighborhoods in a comparative analysis of public life. The collaborative project presented here shows the importance of these centrums in supporting community life in the suburbs. Drawing from Setha Low’s research on public squares in Costa Rica, the following paragraphs suggest public space is not only produced by those who envision it, but also constructed by those who use it, through daily processes, behaviors, and habits. These observed patterns carry significance as they forge the character of a place, and address practices and emotions within a collective identity. The thesis puts emphasis on the dynamic nature of public space, the relationship between morphology and use, and the potential neighborhood centers have for becoming hubs of inclusion.

  • Fique, Simon
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    The production of space: An urban study of the Centrums of Rinkeby, Tensta and Husby2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The Stockholm Municipality has set inclusion at the core of its objectives for the city with its “Vision 2040: A Stockholm for Everyone”. Acknowledging the divide between neighborhoods, the government has brought forward social sustainability as a key component to improve the fast- growing city. This research focuses on three of the most stigmatized neighborhoods of Stockholm: Rinkeby, Tensta, and Husby, where residents are predominantly of foreign background, to offer an alternative way of understanding inclusion. Specifically, this study looks into the public spaces at the center of these three neighborhoods in a comparative analysis of public life. The collaborative project presented here shows the importance of these centrums in supporting community life in the suburbs. Drawing from Setha Low’s research on public squares in Costa Rica, the following work suggest public space is not only produced by those who envision it, but also constructed by those who use it, through daily processes, behaviors, and habits. These observed patterns carry significance as they forge the character of a place, and address practices and emotions within a collective identity. The thesis puts emphasis on the dynamic nature of public space, the relationship between morphology and use, and the potential neighborhood centers have for becoming hubs of inclusion.

  • Bergdahl, Lina
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Urbana och regionala studier.
    Women’s Perceived Safety on Public Transport Journeys: A Qualitative Study2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Women feel more fear than men in public space and when using public transport. This is an inequality in our society which limits women’s mobility and access to public goods. This study aims to qualitatively explore how women experience their public transport trips from a perceived safety perspective in a study of Gullmarsplan. Which elements women focus on during the trips and what they perceive as unsafe was explored, as well as what behaviors and strategies women use to manage their fear of crime. This was explored by first collecting travel diaries using a whole journey approach and then by narrowing the study down to performing walk-alongs in the walking environment at Gullmarsplan. The study found that women focus mostly on the social environment and that their reflections on the physical environment usually are related to perceived indicators of social incivilities and risk of victimization. Gullmarsplan was generally perceived as quite safe during the day but during evenings and nights most women avoided certain places which usually were secluded, difficult to survey or were perceived to attract dangerous others. Defensive adaptation strategies, mainly avoidance strategies and vigilance, were found to be the most commonly used safety strategies by women. Women’s fear of crime likely cannot be completely designed away in the physical environment but will require structural changes that promote gender equality in our society. With that noted, it is important that urban planners and designers are aware of how the physical environment affects women’s perceived safety. This study found that principles of CPTED generally made women feel safer, particularly important were good lighting and natural surveillance. Green spaces such as parks were found to often be avoided by women after dark. The geographical location and use of safety principles such as CPTED is thus especially important at such locations. Urban planners and designers have the power to shape public spaces that are accessible and safe. Public policies and design that promote equality in access to and use of public space is a feature of a more just democratic society.

  • Shammo, Johannes Hanna
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Betti, Saad Faris Asaad
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Skyddsutrustningen och logistikens påverkan på effektiviteten och olyckshändelserna2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The bachelor thesis was performed in cooperation with Erlandsson Bygg Öst. The purpose of this thesis is to find out how the personal protective equipment (PPE) and logistics increase the efficiency of the work and reduce the risk of accidents at building site. The project was to investigate the factors that impact the efficiency and activities some increase the risk for accidence. The study discusses only the PPE and logistics, because it considers as an important for building production. The motivation of this thesis is to look into the factors that can reduce the risk of accident in the future and make it more effective on the building method. In order to carry out the bachelor thesis there has been a combination of literature studies, questionnaires and interviews. The literature studies were in form of books and digital websites. And the interview performed with 2 managers. The questionnaires handed out to the worker that was at building site. After the work has been done was able to draw conclusion about which factors increase the risk of accidents and which factors affect the efficiency. The communication and APD-plan are the shortage of using of the PPE and problem in logistic is the factors that impact the efficiency and accidents. The recommendation has been presented to the company to raise awareness to increase efficiency and reduce the incidence of accidents.

  • Issa, Omar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Issa, Hadi
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Logistiksamordningsprogrammet Myloc Construction2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    En av de största utmaningarna i dagens byggbransch är logistikfrågan, fler och fler projekt påverkas av logistikutmaningar och det är av stor vikt att dessa utmaningar granskas och åtgärdas. Allt fler företag har börjat hantera dessa utmaningar med hjälp av olika logistiksamordningsverktyg för att spara tid, få bättre överblick och planering över materialflödet, minska skador med flera. Syftet på detta examensarbete är att undersöka om logistiksamordningsprogrammet Myloc Construction är ett effektivt samordningssystem att använda vid logistikhantering genom att undersöka hur programmet upplevs på tre olika projekt. Författarna har genom denna undersökning som mål kommit fram till om rätt val av logistikmetod gjorts för de tre projekten, vid vilka sorts projekt Myloc Construction ska användas och om Myloc Construction är ett system som Veidekke ska använda för framtida projekt. I dagsläget så pågår ett till- och ombyggnadsprojekt på tre olika huskroppar av Sergelhuset på Sergels torg där Veidekke, NCC och Zengun genomför projektet i en totalentreprenad i samverkan. Alla tre entreprenader använder sig utav Myloc Construction för sina respektive delar i projektet. Undersökningen har baserats på en kombination av olika vetenskapliga metoder såsom intervjuer, enkäter, litteraturstudier, observationer samt elektroniska källor. För att få en djupare förståelse om Myloc Construction har nio personer som använder programmet intervjuats. Enkätundersökningen delades ut till olika användare av programmet för att få en större helhetsbild. På grund av projektets storlek, placering och komplexitet där flera entreprenader samverkar med varandra så är ett logistikprogram nödvändigt. Programmet kan användas till alla typer projekt men är mest nödvändigt till större och mer komplexa projekt. Förutsatt att Myloc fortsätter att uppdatera sin tjänst både på webben och i mobilen så är det något som kan effektivisera logistiken.

  • Bäckner, Caroline
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Vigert, Tobias
    Kan kostnadsbedömningar i tidiga skeden byggt på BIM utföras?2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Dagens samhälle står i stort inför en förändring gällande digitalisering där kostnadseffektivitet, produktivitet samt digitalisering samspelar. Den svenska byggsektorn har visat sig ha en låg utvecklingsgrad inom digitalisering. Ottosson upplyser om att drygt 80% av alla komplikationer i byggprojekt har sin grund i bristande kommunikation. Svensk byggtjänst har visat att kostnaderna för byggproduktionen och förvaltningen fördyras med omkring 60 miljarder kronor varje år. Det handlar i grund och botten om hur aktörer kommunicerar sinsemellan men även hur information hanteras digitalt. Ett känt begrepp i dagens byggbransch rörande digitalisering och kommunikation är BIM, ”Byggnadsinformationsmodell/modellering”. Konceptet handlar om att skapa och nyttja exakta digitala modeller från byggprojekt. Det går ut på att få fram information från den digitala modellen som är betydande för förverkligandet av byggnadsverket och som då uppfyller konceptet BIM. Begreppet berör informationshanteringen, det vill säga kommunikationen mellan olika aktörer. ÅF-Infrastructure AB sektion ”Byggekonomi – Rådgivning tidiga skeden” tilldelade författarna till detta examensarbete att undersöka en specifik metod för kostnadsbedömningar med hjälp av digitala modeller som underlag. Syftet med detta examensarbete är att utreda förslaget till tillvägagångssätt för kostnadsbedömningar med hjälp av digitala modeller i syfte att utveckla företagets interna kostnadsbedömningsverktyg. I och med detta förfaringssätt kan rätt underlag i rätt stadium inom det tidiga skedet bidra till att öka kvaliteten i fattandet av ekonomiska beslut. Examensarbetet baserar sig på en kvalitativ metod i form av litteraturstudier, intervjuer, deltagande vid ämnesaktuella seminarier, observationer av möten samt en kvantitativ metod utförd i syfte att simulera flerbostadshusprojekt. Metoderna har undersökt möjligheten om informationshanteringssystemen Level Of Development och CoClass kan stå till förfogande med underlag inför kostnadsbedömning utav de tre stadierna inom tidiga skeden: idé- förstudie- och programhandlingsstadiet. Studien har visat på framför allt två utmaningar. Det finns utvecklingspotential både vad gäller klassifikationssystemet CoClass och kostnadsbedömningsverktyget Calc Frame. Gällande CoClass bör det framför allt vara klassifikationssystemet som informerar användaren angående vad som ska inrymmas under respektive informationsnivå. Det bör inte vara upp till näringslivet att tolka vad som ska ingå på respektive informationsnivå utan detta bör förfinas och tydliggöras inne i själva klassifikationssystemet. Ur en kostnadsbedömningssynpunkt har det inte gått att ta fram generiska byggnadsverkskomplex i Calc Frame. Då verktyget klarar av att hantera flera olika byggnadsverk kan dessa således kombineras till specifika och unika byggnadsverkskomplex. Teoretiskt sett skulle utvecklandet av generiska byggnadsverkskomplex vara möjligt om programmet vidareutvecklas. Om detta anses eftersträvansvärt så är vår bedömning att det är möjligt att vidareutveckla och applicera metodiken på byggnadsverkskomplex (med samma princip som programmet är uppbyggt) för att skapa generiska komplex. Vår studie har visat att kostnadsbedömningar i tidiga skeden byggt på BIM går att utföra. Huruvida ÅF-Infrastructure AB,s uppdatering av sitt interna kostnadsbedömningsverktyg är kompatibelt med digitala modeller, anser författarna vara bekräftat i och med att studien har visat att den metod som använts för att öka kvaliteten i kostnadsbedömningar är förenlig med det nya klassifikationssystemet CoClass. Rekommendationen är således att uppdatera samt utveckla kostnadsbedömningsverktyg gentemot klassifikationssystemet CoClass.

  • Disputas: 2019-10-23 10:00 FA32, Stockholm
    De Luca, Eleonora
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvant- och biofotonik.
    Nonlinear Properties of III-V Semiconductor Nanowaveguides2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Nonlinear optics (NLO) plays a major role in the modern world: nonlinear optical phenomena have been observed in a wavelength range going from the deep infrared to the extreme ultraviolet, to THz radiation. The optical nonlinearities can be found in crystals, amorphous materials, polymers, liquid crystals, liquids, organic materials, and even gases and plasmas. Nowadays, NLO is relevant for applications in quantum optics, quantum computing, ultra-cold atom physics, plasma physics, and particle accelerators. The work presented in the thesis is limited only to the semiconductors that have a second-order optical nonlinearity and includes two phenomena that use second-order nonlinearity: second-harmonic generation (SHG) and spontaneous parametric down-conversion (SPDC). Among the many options available, the investigation presented concerns gallium phosphide (GaP) and gallium indium phosphide (Ga0.51In0.49P), two semiconductors of the group III-V with the ¯43m crystal symmetry.

    However, some of the results found can be generalized for other materials with ¯43m crystal symmetry.

    In the thesis, the fabrication of GaP nanowaveguides with dimensions from 0.03 μm and an aspect ratio above 20 using focused ion beam (FIB) milling is discussed. The problem of the formation of gallium droplets on the surface is solved by using a pulsed laser to oxidize the excess surface gallium locally on the FIB-milled nanowaveguides. SHG is used to evaluate the optical quality of the fabricated GaP nanowaveguides. Additionally, a theoretical and experimental way to enhance SHG in nanowaveguides is introduced. This process uses the overlap of interacting fields defined by the fundamental mode of the pump and the second-order mode of the SHG, which is enhanced by the longitudinal component of the nonlinear polarization density. Through this method, it was possible to obtain a maximum efficiency of 10−4, which corresponds to 50 W−1cm−2. The method can be generalized for any material with a ¯43m crystal symmetry. Furthermore, SHG is used to characterize the nonlinear properties of a nanostructure exposed for a long time to a CW laser at 405 nm to reduce the photoluminescence (PL) of Ga0.51In0.49P. The PL was reduced by -34 dB without causing any damage to the nanostructures or modifying the nonlinear properties. The fabrication process for obtaining the nanowaveguide is interesting as well, since the fabricated waveguide in Ga0.51In0.49P, whose sizes are 200 nm thick, 11 μm wide and 1.5 mm long, was transferred on silicon dioxide (SiO2). This type of nanowaveguide is interesting for SPDC, since it satisfies the long interaction length necessary for an efficient SPDC. Finally, a configuration consisting of illuminating the top surface of a nanowaveguide with a pump beam to generate signal and idler by SPDC is presented. These fabricated nanostructures open a way to the generation of counter-propagating idler and signal with orthogonal polarization. By using a different cut of the crystal, i.e. [110], it makes possible to obtain degenerate wavelength generation, and in certain conditions to obtain polarization-entangled photons or squeezed states.

  • Banavase Shivalingappa, Anoop
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Dhamal, Abhishek Chandrakant
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Analysis of Machining Performance using High pressure Minimum Quantity Lubrication (MQL)2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sustainability in manufacturing is a holistic approach. It is viewed in the context of entire manufacturing system of processes, products and raw materials rather than a single component. Metal cutting fluids which play a major role in all machining processes, should be managed efficiently to attain sustainability. One of the techniques by which this can be achieved is Minimum Quantity Lubrication (MQL). Using vegetable oil as a lubricant extracted from rapeseed and delivering this to the cutting zone at high pressures results in better penetration. Thus, forming a layer between cutting tool and workpiece. This reduces friction between the tool and workpiece and effectively reducing cutting temperature. This process contributes to overall increase in tool life and surface roughness of the machined surface. The main objective of this project is to study the tool life, chip morphology and surface roughness associated with the application of Vegetable oil as lubricant in minimum quantity at high pressure and comparing this with conventional flood cooling method. The experiment was carried out at Industriell Production (IIP) laboratory at Kungliga Tekniska Högskolan (KTH) in a CNC turning machine. The material used in this process is hardened steel (TooloxⓇ) provided by SSAB. The cutting Tool is supplied by Mircona AB and the vegetable oil is provided by Accu - Svenska AB. The experimental results unveiled convincing results with the usage of MQL at constant pressure of 12 bar at 7 mL/hr and 14 mL/hr respectively and varying pressures of 9 bar and 6 bar. The improvement in tool life and surface roughness which can be attributed in the order of outlet pressure is as follows:12 bar with dual coolant flow, 12 bar, 9 bar and 6 bar. The detailed explanation of this is provided in the results and discussion section. There is lot of scope for further study by increasing the pressure of MQL using additional boosters and applying this method to other machining processes such as milling, drilling and grinding. The study regarding the benefits of Vegetable oil as an MQL fluid could also reveal interesting results and positive effects to environmental and operator’s health.

  • Gustafsson, Robin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Fröjdendahl, Lucas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Machine Learning for Traffic Control of Unmanned Mining Machines: Using the Q-learning and SARSA algorithms2019Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Manual configuration of rules for unmanned mining machine traffic control can be time-consuming and therefore expensive. This paper presents a Machine Learning approach for automatic configuration of rules for traffic control in mines with autonomous mining machines by using Q-learning and SARSA. The results show that automation might be able to cut the time taken to configure traffic rules from 1-2 weeks to a maximum of approximately 6 hours which would decrease the cost of deployment. Tests show that in the worst case the developed solution is able to run continuously for 24 hours 82% of the time compared to the 100% accuracy of the manual configuration. The conclusion is that machine learning can plausibly be used for the automatic configuration of traffic rules. Further work in increasing the accuracy to 100% is needed for it to replace manual configuration. It remains to be examined whether the conclusion retains pertinence in more complex environments with larger layouts and more machines.

  • Kuthe, Sudhanshu
    KTH, Skolan för industriell teknik och management (ITM).
    Multimaterial 3D Printing of a mechanically representative aortic model for the testing of novel biomedical implants2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Aortic stenosis is a serious cardiovascular disease that requires urgent attention and surgical intervention. If not treated, aortic stenosis can result in heart attack or cardiac arrest. Transcatheter Aortic Valve Replacement is a surgical technique that is used to treat aortic stenosis. Like all heart surgery, the procedure is difficult to perform and may lead to life-threatening complications. It is therefore important for a surgeon to be able to plan and rehearse the surgery before the operation to minimise risk to the patient.

    A detailed study was carried out to develop a 3D-printed, improved surgical tool for patient-specific planning and rehearsal of a Transcatheter Aortic Valve Replacement procedure. With this new tool, a cardiologist will be able better to understand a specific patient’s heart geometry and practice the procedure in advance. Computer tomography images were processed using image segmentation software to identify the anatomy of a specific patient’s heart and the surrounding blood vessels. Using materials design concepts, a polymer composite was developed that is able to mimic the mechanical properties of aortic tissue. State-of-art multi-material 3D printing technology was then used to produce a replica aorta with a geometry that matched that of the patient. An artificial aortic valve, identical to the type used in the Transcatheter Aortic valve replacement procedure, was then fitted to the replica aorta and was shown, using a standard test, to be a good fit with no obvious leaks.

  • Picard, Tom
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Matematisk statistik.
    Inference and filtration of a hidden factor in credit risk2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Document is a Master Thesis report as part of the cycle of the ENSIMAG and KTH engineer. The internship linked to this report took place at Nexialog Consulting, Paris.This document deals with the inference and filtration by a counting process of a hidden parameter. The theory developed here is applied to Credit risk and specially to Migration Matrices of Rating.

  • Hemmingsson, Nils
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Matematik (Avd.).
    On the dynamics of a family of critical circle endomorphisms2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis we study two seperate yet related three parameter-families of continuously differentiable maps from the unit circle to unit circle which have a single critical point. For one of the families we show that there is a set of positive measure of parameters such that there is a set of positive measure for which all points in the latter set, the derivative experiences exponential growth. We do so by applying a similar methodology to what Michael Benedicks and Lennart Carleson used to study the quadratic family. For the other family we attempt to show a similar but weaker result using a similar method, but do not manage to do so. We expound on what difficulties the latter family provides and what features Benedicks and Carleson used for the quadratic family that we do not have available.

  • Stiti, Karim
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Yape, Shih Jung
    KTH, Skolan för industriell teknik och management (ITM).
    Bid Forecasting in Public Procurement2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Public procurement amounts to a significant part of Sweden's GDP. Nevertheless, it is an overlooked sector characterized by low digitization and inefficient competition where bids are not submitted based on proper mathematical tools. This Thesis seeks to create a structured approach to bidding in cleaning services by determining factors affecting the participation and pricing decision of potential buyers. Furthermore, we assess price prediction by comparing multiple linear regression models (MLR) to support vector regression (SVR). In line with previous research in the construction sector, we find significance for several factors such as project duration, location and type of contract on the participation decision in the cleaning sector. One notable deviant is that we do not find contract size to have an impact on the pricing decision. Surprisingly, the performance of MLR are comparable to more advanced SVR models. Stochastic dominance tests on price performance concludes that experienced bidders perform better than their inexperienced counterparts and companies place more competitive bids in lowest price tenders compared to economically most advantageous tenders (EMAT) indicating that EMAT tenders are regarded as unstructured. However, no significance is found for larger actors performing better in bidding than smaller companies.

  • Disputas: 2019-10-25 14:00 F3, STOCKHOLM
    Bakyayita, Grace Kizito
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik. Makerere University, Kyambogo University.
    Batch Sorption Studies of Aqueous Cadmium and Lead from Contaminated Water onto Selected Biosorbents2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Groundwater, wastewater, surface runoff and surface water samples from Lake Victoria basin, Uganda was assessed for trace metals contamination. Untreated, base-treated and peroxide-treated biosorbents from Albizia coriaria, Coffea canephora, Cyperus papyrus, Erythrina abyssinica and Musa spp were investigated for removal of selected trace metals from contaminated water in batch studies. The assessed shallow groundwater and surface water was contaminated with iron and manganese. Selected speciation studies using Visual MINTEQ showed that in leachates from Municipal dumpsites 74% of the metal ions were bound to DOM, 13% were free ions and 13% were in inorganic forms moreover for urban streams 37% of the metal ions were bound to DOM, 44% were free ions and 19% were in inorganic forms. The metal levels in surface water, landfill leachate and surface runoff showed elevated levels and revealed increased risks to environmental health. Risk analysis based on the Swedish EPA showed that varied risks of negative effects in 30% – 76% of the sample sites ranging from high to increased risk in surface water whereas the results from Bio-met tool showed potential risk to toxicity effects of Cu2+, Ni2+, Zn2+ and Pb2+ in 15.3% - 30.8% surface water samples and 8.3% - 62.5% groundwater samples. Batch sorption studies revealed that the optimal conditions for Cd2+ and Pb2+ ions uptake were; pH 3.5 – 5.0 for contact time 3.0 – 3.5 hours and biosorbent dosage 10 – 12.5 g/L. Base-treated biosorbents showed 10 – 17 % sorption enhancement for Cd2+ ions and 1.6 – 2.3 % uptake reduction for Pb2+ ions. The biomass negative potential for binding base cations was in the order; Musa spp. > A. coriaria > E. abyssinica and base treatment reduced DOC leaching from biosorbents in the order; E. abyssinica > A. coriaria > Musa spp. Speciation studies showed that more ions were complexed to DOC in solutions at various pH levels. The maximum sorption intensities for both Cd2+ and Pb2+ ions uptake onto biomass occurred for low initial metal concentration; 5 mg/L. Freundlich model best fitted data for Pb2+ ions ions uptake whereas Temkin model fitted the sorption data for Cd2+ ions onto both treated and untreated biomass. For peroxide treated biomass, the maximum sorption efficiencies for both Cd2+ and Pb2+ ions were between 95.2 – 98.7% for C.canephora, 79.9 – 92.2% for Musa spp. and 42.0 – 91.3% for C.papyrus in non-competitive media and 90.8 – 98.0% for C.canephora, 56.4 – 89.3% for Musa spp. and 19.5 – 90.4% for C.papyrus in competitive media. The Langmiur model fitted non-competitive sorption data with 0.769 ≤ R2 ≥ 0.999 and the Freundlich model fitted competitive sorption data with 0.867 ≤ R2 ≥ 0.989. The pseudo second order kinetic model fitted the sorption data for Cd2+ and Pb2+ ions for untreated, peroxide treated and base treated biomass with 0.917 ≤ R2 ≥ 1.000. The sorption of trace metals was a complex potentially monolayer chemisorption with heterogeneous surface properties exhibited. In competitive sorption, sorption suppression effects observed were greater for Cd2+ than Pb2+ ions. The comparative studies on sorption performance presented agreement and no significant difference between the untreated and base treated biosorbents. 

  • Hamadi, Farah
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Wallin, Viktor
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Förseningstimmar på mötesseparerade 2+1-vägar: Hur förseningskostnaden påverkas av ombyggnad till 2+2-väg i relation till investeringskostnaden2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Från slutet av 1990-talet har en stor mängd av de icke-separerade 13 meter breda vägarna byggts om till mötesseparerade vägar, där trafiken i varje riktning separeras med en mittremsa. Mötesseparerade vägar har varit ett mycket lyckat projekt för trafiksäkerheten och bidragit med en stor minskning av svårt skadade och döda i trafiken. Det finns många mötesseparerade vägar i Sverige. Vid olyckor på 2+1-vägar blir det svårt för trafiken att vända på vägen vilket leder till stopp och gör det även svårt för Blåljusmyndigheten samt bärgningsbilar att ta sig fram. Dessa olyckor leder till förseningstimmar och i sin tur till samhällskostnader. Det här examensarbetet är skrivet för Trafikverket för att granska 2+1-vägar i Trafikverkets Region Öst. Rapporten tar fram och jämför minskning av förseningskostnader efter en ombyggnad från 2+1- till 2+2-väg, rapporten tar även fram och jämför förseningskostnaden med investeringskostnaden för ombyggnationen. Resultatet för den här studien har framförts genom litteraturstudier, analys av data från Trafikledningen, webbverktyg och genom användning av Microsoft Excel för kalkylering av förseningstimmar och -kostnader för utvalda vägar och sträckor. Resultatet från rapporten visar om det är värt att undersöka en 2+1-väg för ombyggnation från 2+1- till 2+2-väg ur förseningskostnadsperspektiv. Detta redovisas genom en generell jämförelse per mil 2+1-väg baserad på väg 50, 55 och 56 i Trafikverkets Region Öst. Rapporten innehåller även en analys över de fem mest drabbade olycksplatserna på E18:s 2+1 sträckor. Analysen av dessa visade att alla fem sträckor låg mellan Köping och Västerås i Västmanland.

  • Mohammadnia, Hamzeh
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    IoT-NETZ: Spoong Attack Mitigation in IoT Network2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The phenomenal growth of the Internet of Things (IoT) and popularity of the mobile stations have rapidly increased the demand of WLAN network (known as IEEE 802.11 and WiFi). WLAN is a low-cost alternative of the cellular network and being an unlicensed spectrum to build the master plan of embedding the Internet in everything -&-anywhere. At the same time, monitoring the number of IoT and WiFi-enabled devices across residential and enterprises is not trivial. Therefore, future WiFi network architecture requires an agile management paradigm to provide internal support and security for WiFi networks.The operation of IoT and mobile device applications relies on scalability and high-performance computing of clouds. Cloud computing has completely centralized the current data center networking architecture and it provides computation-intensive, high-speed network, and realtime responses to the requests of IoT. The IoT-to-cloud communication is the essence of network security concerns and it is in grievous need of constant security improvement along the inter-networking. Based on the number of researches and analysis on generated traffic by IoT, it has been observed there are the significant number of massive spoofing-oriented attacks targeting cloud services are launched from compromised IoT.On the basis of reviewing prior researches on mostly-conducted network attacks by IoT, there is a challenging and common characteristic which has been frequently utilized in the numerous massive Internet attacks, known as spoofing. This work will survey the existing proposed solutions which have been deployed to protect both traditional and softwarized network paradigms. Then, it proposes the approach of this work that enables IoT-hosting networks protected by employing Software-defined Wireless Networking (SDWN) within the proposed model to mitigate spoofing -oriented network attacks. In addition, the proposed solution provides the environmental sustainability feature by saving power consumption in networking devices during network operation. The practical improvement in the proposed model is measured and evaluated within the emulated environment of Mininet-WiFi.

  • Franzén, Henny
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Elmondt Nilsson, Carl
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Akustiska värden i platonkonstruktioner: Minimera lågfrekvent buller i skolmiljöer2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I denna studie har man fokuserat på hur omfattande ljudnivåerna kan vara på ett så kallat flytande golv. Det har fördjupats i konstruktioner med Platonmatta för att få en uppfattning om hur de akustiska faktorerna yttrar sig när någon beträder golvet. Studien jämför resultat av steg- och trumljudnivåer med Granabkonstruktioner, som är en annan typ av flytande golv, samt hur Platonkonstruktionen står sig i förhållande till de lagstadgade riktvärdena. I denna studie har det fokuserats på hur ljudet uppfattas både objektivt och subjektivt eftersom mätvärden i vissa fall inte stämmer överens med den faktiska upplevelsen. Golvtesterna som genomförts har gett oss mätvärden och en objektiv upplevelse. Detta har resulterat i en optimal golvkonstruktion teoretiskt. Sammantaget visar denna studie att golvens konstruktion i stor utsträckning kan minimera steg- och trumljud. Alla Platonkonstruktioner som testats i studien har generellt gett bra akustiska värden för att vara ett överliggande golv. Den kunskapen kan vara till stor nytta när man projekterar ett flytande golv eftersom höga ljudnivåer i de lägre frekvenserna har visat sig påverka bland annat inlärnings- och koncentrationsförmågan.

  • Cleve, Oscar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Gustafsson, Sara
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Automatic Feature Extraction for Human Activity Recognitionon the Edge2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis evaluates two methods for automatic feature extraction to classify the accelerometer data of periodic and sporadic human activities. The first method selects features using individual hypothesis tests and the second one is using a random forest classifier as an embedded feature selector. The hypothesis test was combined with a correlation filter in this study. Both methods used the same initial pool of automatically generated time series features. A decision tree classifier was used to perform the human activity recognition task for both methods.The possibility of running the developed model on a processor with limited computing power was taken into consideration when selecting methods for evaluation. The classification results showed that the random forest method was good at prioritizing among features. With 23 features selected it had a macro average F1 score of 0.84 and a weighted average F1 score of 0.93. The first method, however, only had a macro average F1 score of 0.40 and a weighted average F1 score of 0.63 when using the same number of features. In addition to the classification performance this thesis studies the potential business benefits that automation of feature extractioncan result in.

  • Celik, Engin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Bohman, Tobias
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Leveransstörningar i produktion: En undersökning av JM:s leveransprecision och arbetsledarnas nyttjande av digitala verktyg2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Logistik- och leveransprocessen i byggsektorn har alltid varit ett problematiskt område. Till följd av att byggnadsprojekt sker i projektform och produktionen är platsbaserad blir det svårt att skapa standardiserade logistikflöden. Detta innebär att effektiva metoder måste tillämpas för att kunna uppnå en optimal logistikprocess. En av dessa metoder är implementeringen av digitala verktyg. Genom digitala system som underlättar kommunikation och informationsöverföring mellan alla parter syftar byggföretag till att främja bygglogistiken. Däremot är digitaliseringen i byggbranschen fortfarande ett utvecklingsområde och nyttjandet av digitala verktyg på byggarbetsplatser är än idag lågt. Denna rapport behandlar leveransstörningar i produktion och undersöker frekvensen av inrapporterade leveransstörningar i JM:s digitala system. Syftet med detta examensarbete är att belysa bristerna med JM:s digitala verktyg och samtidigt förbättra nyttjandet av dessa. Ett annat syfte är att ta reda på mörkertalet gällande leveransstörningarna. Studien är avgränsad till fyra projekt söder om Stockholm och den fältstudie som utförs avser en period på fyra veckor. Undersökningen som pågår på dessa projekt är indelad i kvantitativa och kvalitativa metoder. På projekten utförs intervjuer med arbetsledare och parallellt med detta sker även egna statistikinmätningar av leveransprecisionen. Utöver det genomförs även granskningar av JM:s digitala system. De digitala verktyg som berör denna rapport är avropssystemet, inköpssystemet och BI-systemet. Fältstudiens resultat visade att leveransprecisionen var 69 %. I motsats till detta redovisade JM:s statistik 89 %. Differensen och således mörkertalet blev alltså 20 procentenheter. Arbetsledarna ansåg att avropssystemets komplexitet var en stor orsak till det låga nyttjandet. Fältstudien påvisade även att följande faktorer var en bidragande orsak till den låga användningen av systemen: • Bristen på tid • Leveransstörningens storlek • Leverantörernas bristande kunskap om avropssystemet • Inköpssystemets nya design För att uppnå en högre leveransprecision på byggarbetsplatserna behöver JM:s digitala system genomgå förändringar och bli mer användarvänliga. Systemen måste utformas och anpassas efter arbetsledarnas vardag. Detta kommer i sin tur medföra att JM centralt kan samla in mer data och få bättre möjlighet till kontroll.

  • Heiska, Mirjami
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Assessing the environmental impacts of a tool rental service from Husqvarna using Life Cycle Assessment  Confirmation that the opposition is completed2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To decouple ever-increasing production and the related environmental impacts, collaborative use of products and product-service-systems including rental services can help to intensify the use of products during their designed lifetimes. While these approaches present potential to decrease environmental impacts compared to traditional linear product sales, they need to be assessed with a holistic scope to avoid counterintuitive trade-offs.

    This study evaluates the potential environment impacts of Husqvarna’s tool rental service with a hypothetical case example from Stockholm, Sweden. The objectives are to analyse the potential environmental impacts of the rental service, to identify hotspots for improvement and to compare the potential impacts of the rental system to a sales alternative. The annual service of one electric chainsaw is analysed using Life Cycle Assessment (LCA) methodology with different user scenarios. The potential impacts are analysed for global warming potential, fossil and mineral resource scarcity, marine ecotoxicity and human carcinogenic and non-carcinogenic toxicity.

    The analysis for the rental system shows that user transport back-and-forth to the rental service is a key contributor to all the environmental impacts analysed, if done by private cars. The comparative results to sales business model indicate that while the rental service can help to reduce the potential impacts in mineral resource scarcity and toxicities due to the lower number of products needed, the user transport may outweigh the potential improvements in global warming potential and fossil resource scarcity, depending on the distances and modes of transport. Different scenarios illustrate that the results are however sensitive to the assumptions made.

    Based on the results, it can be recommended to optimally place the service close to the users and to take efforts to reduce user transports around the service, to reach the environmental potential of the service. The sensitivity analyses also indicate the importance for accounting detailed data for LCAs for product-service-systems and covering the service holistically in system boundaries. Further studies on user behaviour are suggested to reach more robust analyses on consumer services, to cover also potential rebound effects.

  • Berglund, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Analys av olika positioneringssystem för Trafikförvaltningens järnvägsbanor2019Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Positioneringssystem har en vital roll när det gäller att kontrollera säkra tågrörelser. Det finnsmånga olika typer av positioneringssystem. Det här arbetet behandlar hur axelräknare, communications-based train control (CBTC) och olika typer av spårledningar fungerar. Det innehåller ocksåen analys av växelströmsspårledningar och axelräknare med RAMS-parametrar (Reliability, Availability,Maintenance and Safety) som utgångspunkt för att dra slutsats om vilken typ som passar bästför Trafikförvaltningens spårburna banor. Genom intervjuer med erfarna personer inom järnvägsbranscheni Stockholm erhölls kunskap om för- och nackdelar med olika system. En felträdsanalys(FTA) utfördes för axelräknare och spårledningar för att åskådliggöra potentiellt farliga situationer.Felstatistik för två järnvägsbanor togs fram för att visa felfrekvens för en bana med axelräknare ochen bana med spårledningar. Resultatet är inte entydigt men visar ändå att axelräknare undvikerfelkällor som finns hos spårledningar. Det som tydligast kommit fram var att förvaltningen behöverstandardisera till färre typer av system för de olika banorna. Det skulle underlätta vid förvärvandetav personal med rätt kompetens som ska utföra underhåll. Det skulle också göra det lättare att säkerställatillgången till ersättningsprodukter.

  • Pham, Trang A.T.
    et al.
    Schwerdt, Julian G.
    Shirley, Neil J.
    Xing, Xiaohui
    Hsieh, Yves S. Y.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Srivastava, Vaibhav
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Bulone, Vincent
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Little, Alan
    Analysis of cell wall synthesis and metabolism during early germination of Blumeria graminis f. sp. hordei conidial cells induced in vitro2019Inngår i: The Cell Surface, ISSN 2468-2330, Vol. 5, s. 100030-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As an obligate biotroph, Blumeria graminis f. sp. hordei (Bgh) cannot be grown in an axenic culture, and instead must be cultivated on its host species, Hordeum vulgare (barley). In this study an in vitro system utilizing n-hexacosanal, a constituent of the barley cuticle and known inducer of Bgh germination, was used to cultivate Bgh and differentiate conidia up to the appressorial germ tube stage for analysis. Transcriptomic and proteomic profiling of the appressorial germ tube stage revealed that there was a significant shift towards energy and protein production during the pre-penetrative phase of development, with an up-regulation of enzymes associated with cellular respiration and protein synthesis, modification and transport. Glycosidic linkage analysis of the cell wall polysaccharides demonstrated that during appressorial development an increase in 1,3- and 1,4-linked glucosyl residues and xylosyl residues was detected along with a significant decrease in galactosyl residues. The use of this in vitro cultivation method demonstrates that it is possible to analyse the pre-penetrative processes of Bgh development in the absence of a plant host.

  • Bommakanti, Hemanth Ram Kartik
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Impact of Time Synchronization Accuracy in Integrated Navigation Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Global Navigation Satellite System/Inertial Measurement Unit (GNSS/IMU) Integrated Navigation Systems (INS) integrate the positive features of GNSS and IMU for optimal navigation guidance in high accuracy outdoor navigation systems, for example using Extended Kalman Filter (EKF) techniques. Time synchronization of IMU data with precise GNSS based time is necessary to accurately synchronize the two systems. This must be done in real-time for time sensitive navigation applications such as autonomous vehicles. The research is done in two parts. The first part is the simulation of inaccurate time-stamping in a single axis of nonlinear input data in a gyroscope and an accelerometer, to obtain the timing error value that is tolerable by a high accuracy GNSS/INS system. The second part is the creation of a real-time algorithm using an STM32 embedded system enabled with FreeRTOS real-time kernel for a GNSS receiver and antenna, along with an IMU sensor. A comparative analysis of the time synchronized system and an unsynchronized system is done based on the errors produced using gyroscope and accelerometer readings along a single axis from the IMU sensor, by conducting static and rotational tests on a revolving chair.The simulation concludes that a high accuracy GNSS/INS system can tolerate a timing error of up to 1 millisecond. The real-time solution provides IMU data paired with updated GNSS based time-stamps every 5 milliseconds. The timing jitter is reduced to a range of ±1 millisecond. Analysis of final angular rotation error and final position error from gyroscope and accelerometer readings respectively, indicate that the real-time algorithm produces a reduction in errors when the system is static, but there is no statistical evidence showing the reduction of errors from the results of the rotational tests.