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  • 1451.
    Abhijeet, Kumar
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Governing water pollution effectively: A comparative study of legal frameworks & their implementation in India & Sweden.2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Case studies from India have shown that the legal regime governing water pollution control in India has miserably failed. Sectoral approach to water management is quite evident. On the other hand Sweden has shown a remarkable change with regard to environment management. The poor management of a resource makes the resource further poor. Thus effective management of the resources becomes crucial. Good governance has been vital in conservation of a resource. But the issue is what constitutes good governance with respect to water? Law has always played a steering role in governance aspect. But despite having pollution control laws the effective governance of water pollution has not been attainable in India. Are the pollution control laws fundamentally wrong or some other factors prevail which is beyond the reach of law to control the pollution problem. The thesis which is a comparative study of legal framework and their implementation in India and Sweden attempts to explore how control of water pollution has been effectively governed in Sweden and what needs to been done in India.

  • 1452.
    Abid, Fahim
    et al.
    KTH.
    Ghorbani, Hossein
    Pourrahimi, Amir Masoud
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edin, Hans Ezz
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Differences in morphology and polarization properties of heat-treated XLPE and LDPE insulation2016In: 2016 IEEE CONFERENCE ON ELECTRICAL INSULATION AND DIELECTRIC PHENOMENA (IEEE CEIDP), IEEE conference proceedings, 2016, p. 113-116Conference paper (Refereed)
    Abstract [en]

    Cross-linked polyethylene (XLPE) is the most commonly used insulating material for extruded high voltage cable applications. Degassing is a heat-treatment process that is performed to remove methane from XLPE insulation which is formed during the crosslinking reactions as a by-product. Apart from removing methane, heat-treatment influences the electrical properties through changing the morphology due to annealing and also removal of polar crosslinking by-products. Scanning electron microscopy (SEM) is generally used to observe the changes in crystalline structure of the polymer. Frequency domain spectroscopy (FDS) is widely used to study polarization properties of dielectric materials. In this study these two methods are used for a comparative analysis of XLPE and LDPE subjected to different heat-treatment time, with or without a diffusion barrier. Electrical measurements are performed at room temperature. From the SEM imaging conducted after permanganate acid etching, formation of spherulites due to heat-treatment is not obvious in neither LDPE nor in XLPE. However, distinctions between LDPE and XLPE in SEM micrographs are evident. From studies with dielectric polarization spectroscopy, it is found that the LDPE samples are less sensitive to heat-treatment in comparison to the XLPE samples while dissipation factor of XLPE samples are influenced by the choice of pressing film used during sample preparation.

  • 1453.
    Abid, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Global Supply Chain Design: Exploring configurational and coordination factors2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis addresses the topic of global supply chain design. One major challenge concerns how to manage the tension between separation and integration pertaining to the localization of business activities. In this regard Ferdows (2008) worked to create two new production network models (rooted production network and footloose production network). Earlier studies have highlighted the choices that are involved in the network of facilities but lack in providing a comprehensive picture in terms of both configurational and coordination factors that govern the design of global supply chain. There is a need for a conceptual model where factors affecting the design process of a global supply chain can be applied. Two main research questions have been addressed in this study. First, exploring and identifying the factors affecting global supply chain design. Second, investigating the factors that influence the position on the spectrum of rooted and footloose supply chain design.      

    A literature review analysis and multi-case studies have been performed for this study in order to explore the factors. The companies were selected in order to reflect upon the two types of network, i.e., rooted and footloose. The primary data were selected through interviews with the managers.

    This study highlighted that there are many factors that affect configurational and coordination decision areas within a global supply chain. This study categorized the factors and the configurational/coordination decision areas with two main competitive priorities, i.e., cost and differentiation in the form of a “conceptual model.” The study also highlighted the factors in a matrix, which showed their position on the spectrum of rooted and footloose network configurations. For instance, the coordination factors that drive towards a footloose network include: high orchestration capabilities, need access to new technology and knowledge, proximity to suppliers, etc. The configurational factors that drive towards a rooted network include: economic stability, proximity to market, concerns for sustainability issues, high transportation cost, need for high proximity between key functions, need for intellectual property rights protection, etc.

  • 1454.
    Abid, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Högskolan i Gävle, Sweden.
    Relationship between competitive priorities and global supply chain design: A conceptual frameworkManuscript (preprint) (Other academic)
  • 1455.
    Abid, Muhammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Högskolan i Gävle, Sweden.
    Bengtsson, Lars
    Dabhilkar, Mandar
    Factors affecting shifts in global supply chain networks: A configurational approach2013In: Proceedings of the 20th International Annual EurOMA conference, Dublin, Ireland, 9-12 June 2013, 2013, 2013Conference paper (Refereed)
    Abstract [en]

    In certain situations, global companies strive to take advantage of short-term changes in economic and exchange rates on the never-ending journey of competitiveness. This paper seeks to extend Ferdows’s (2008) production network models by adding the factors affecting shifts between rooted and footloose network configurations. Two companies were selected in order to illustrate the models and reveal other possible factors. The identified factors are differentiated in terms of configuration and coordination and merged in a matrix. The trends and implications on global supply chains are also discussed.

  • 1456.
    Abid, Muhammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Högskolan i Gävle, Sweden.
    Bengtsson, Lars
    Hellberg, Roland
    Dabhilkar, Mandar
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Factors affecting global supply chain design2012Conference paper (Refereed)
    Abstract [en]

    Due to the limited existing knowledge pertaining to the factors which govern localization of operations and capabilities in a global supply chain, the purpose of the paper is to find out which factors and how they jointly affect the design of global supply chains. The relevant literature is reviewed and a concept matrix is developed. Five companies were selected in order to illustrate the issues of global supply chain design. Among them, three companies are considered to have efficient supply chain and less complex products, while the two others are considered to have responsive supply chain and more complex products. The issues discussed with the selected companies cover global sourcing, challenges, technological advancement and issues related to management control. The study identifies about fifty factors that affect global supply chain design, and specifically how theses relate to design decisions on location of factories and production, supplier selection and development, distribution of products and organisation of interfaces along the supply chain. The discrepancies between theory and practice as well as the implications for further research are discussed.

  • 1457.
    Abid, Muhammad Zeeshan
    KTH, School of Information and Communication Technology (ICT). Technische Universität Braunschweig.
    A Multi-leader Approach to Byzantine Fault Tolerance: Achieving Higher Throughput Using Concurrent Consensus2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Byzantine Fault Tolerant protocols are complicated and hard to implement.Today’s software industry is reluctant to adopt these protocols because of thehigh overhead of message exchange in the agreement phase and the high resourceconsumption necessary to tolerate faults (as 3 f + 1 replicas are required totolerate f faults). Moreover, total ordering of messages is needed by mostclassical protocols to provide strong consistency in both agreement and executionphases. Research has improved throughput of the execution phase by introducingconcurrency using modern multicore infrastructures in recent years. However,improvements to the agreement phase remains an open area.

    Byzantine Fault Tolerant systems use State Machine Replication to tolerate awide range of faults. The approach uses leader based consensus algorithms for thedeterministic execution of service on all replicas to make sure all correct replicasreach same state. For this purpose, several algorithms have been proposed toprovide total ordering of messages through an elected leader. Usually, a singleleader is considered to be a bottleneck as it cannot provide the desired throughputfor real-time software services. In order to achieve a higher throughput there is aneed for a solution which can execute multiple consensus rounds concurrently.

    We present a solution that enables multiple consensus rounds in parallel bychoosing multiple leaders. By enabling concurrent consensus, our approach canexecute several requests in parallel. In our approach we incorporate applicationspecific knowledge to split the total order of events into multiple partial orderswhich are causally consistent in order to ensure safety. Furthermore, a dependencycheck is required for every client request before it is assigned to a particular leaderfor agreement. This methodology relies on optimistic prediction of dependenciesto provide higher throughput. We also propose a solution to correct the course ofexecution without rollbacking if dependencies were wrongly predicted.

    Our evaluation shows that in normal cases this approach can achieve upto 100% higher throughput than conventional approaches for large numbers ofclients. We also show that this approach has the potential to perform better incomplex scenarios

  • 1458.
    Abili Nejad, Maryam
    KTH, Superseded Departments, Chemistry.
    Kinetics for oxidation of CRUD model compounds2004Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The formation of CRUD (Chalk River Unidentified Deposit) inwater-cooled nuclear reactors constitute a severe problem. Thestability of CRUD under reactor conditions (high flux ofionizing radition, high temperature and pressure) must be knownin order to minimize the problem. The kinetics for CRUDoxidation by H2O2 and the two more potent oxidants IrCl62-and MnO4- has been studied using aqueous suspensions ofthree metal oxide powders, Fe3O4, Fe2CoO4 and Fe2NiO4. The metal oxides were used as model compounds forCRUD. The latter two oxidants were employed to study therelationship between kinetics and the reduction potential ofthe oxidant. In addition, the activation energies for thereaction between H2O2and the three metal oxides of CRUD model weredetermined. The mechanism of the reaction is discussedindicating that the final solid product in all three cases isFe2O3. Our experimental results show that the reactivityof the metal oxides towards oxidants is in the order Fe2CoO4>Fe3O4>Fe2NiO4. The relative reactivities of Fe2CoO4 and Fe3O4are in contrast with that expected from the studyof the ionization potentials of the divalent metals in theoxides. In addition to the experimental studies, thetheoretical grounds for kinetics of reactions in particlesolutions are discussed. The theoretical discussion is alsoused to explain the somewhat unexpected trends in reactivityobserved experimentally. The same reaction trend is alsoobserved in the reaction of the metal oxides with IrCl62-and MnO4-.

    We found experimentally that the logarithm of second orderrate constants of the reaction of metal oxides with oxidantsagainst the one electron potential of the oxidants follows aparabolic behavior in agreement with the Marcus theory forelectron transfer reactions. This work constitutes a good basisfor the design of further model studies aiming at resolving thestability of CRUD under reactor conditions.

    Keywords:Reactor Chemistry, Radiolysis, Oxidation,Kinetics, CRUD, Metal oxide

  • 1459. Abi-Rached, Laurent
    et al.
    Jobin, Matthew J.
    Kulkarni, Subhash
    McWhinnie, Alasdair
    Dalva, Klara
    Gragert, Loren
    Babrzadeh, Farbod
    Stanford University, United States .
    Gharizadeh, Baback
    Luo, Ma
    Plummer, Francis A.
    Kimani, Joshua
    Carrington, Mary
    Middleton, Derek
    Rajalingam, Raja
    Beksac, Meral
    Marsh, Steven G. E.
    Maiers, Martin
    Guethlein, Lisbeth A.
    Tavoularis, Sofia
    Little, Ann-Margaret
    Green, Richard E.
    Norman, Paul J.
    Parham, Peter
    The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 334, no 6052, p. 89-94Article in journal (Refereed)
    Abstract [en]

    Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic human leukocyte antigen (HLA) class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.

  • 1460. Abkar, A.
    et al.
    Hedenmalm, Håkan
    A Riesz representation formula for super-biharmonic functions2001In: Annales Academiae Scientiarum Fennicae Mathematica, ISSN 1239-629X, E-ISSN 1798-2383, Vol. 26, no 2, p. 305-324Article in journal (Refereed)
    Abstract [en]

    Let u be a real-valued function defined on the unit disk D. We call u super-biharmonic provided that u is locally integrable and the bi-laplacian Delta (2)u is a positive distribution on D. In this paper, we shall establish a representation formula for super-biharmonic functions, This formula can be regarded as an analogue of the Poisson-Jensen representation formula for subharmonic functions.

  • 1461. Aboelfotoh, M. O.
    et al.
    Frojdh, C.
    Petersson, C. Sture
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Schottky-barrier behavior of metals on n- and p-type 6H-SiC2003In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 67, no 7Article in journal (Refereed)
    Abstract [en]

    The Schottky-barrier height of a number of metals (Ti, Ni, Cu, and Au) on n- and p-type Si-terminated 6H-SiC has been measured in the temperature range 150-500 K. It is found that the barrier height to n-type 6H-SiC does not exhibit a temperature dependence, while for p-type 6H-SiC the change in the barrier height with temperature follows very closely the change in the indirect energy gap in 6H-SiC. These results are inconsistent with models of Schottky-barrier formation based on the concept of a charge neutrality level. Furthermore, the present results cannot be reconciled with a defect pinning mechanism, contrary to the conclusions of earlier studies on III-V compound semiconductors. We suggest that chemical bonding at the metal-semiconductor interface plays an important role in determining the Schottky-barrier height.

  • 1462.
    Abolafya, Natan
    KTH, School of Information and Communication Technology (ICT).
    Secure Documents Sharing System for Cloud Environments2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the current trend of cloud services available in every market area in IT business, it is somewhat surprising that security services are not migrated to the cloud widely. Security as a Service (SECaaS) model is hardly popular at the moment even though the infrastructure of the cloud, or web, can support most of the functionalities of conventional distributed security services.

    Another uncommon phenomenon in the cloud is sharing secure files with multi-tenant support. This kind of service would be best available integrated with a SECaaS platform that may offer more similar application services. This thesis proposes, studies, designs, develops and evaluates a Secure Documents Sharing System for Cloud Environment with the possibility of integrating to a SECaaS platform.

  • 1463. Abolhassani, M.
    et al.
    Chan, T. -HH.
    Chen, Fei
    KTH.
    Esfandiari, H.
    Hajiaghayi, M.
    Mahini, H.
    Wu, X.
    Beating ratio 0.5 for weighted oblivious matching problems2016In: Leibniz International Proceedings in Informatics, LIPIcs, Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing , 2016Conference paper (Refereed)
    Abstract [en]

    We prove the first non-trivial performance ratios strictly above 0.5 for weighted versions of the oblivious matching problem. Even for the unweighted version, since Aronson, Dyer, Frieze, and Suen first proved a non-trivial ratio above 0.5 in the mid-1990s, during the next twenty years several attempts have been made to improve this ratio, until Chan, Chen, Wu and Zhao successfully achieved a significant ratio of 0.523 very recently (SODA 2014). To the best of our knowledge, our work is the first in the literature that considers the node-weighted and edge-weighted versions of the problem in arbitrary graphs (as opposed to bipartite graphs). (1) For arbitrary node weights, we prove that a weighted version of the Ranking algorithm has ratio strictly above 0.5. We have discovered a new structural property of the ranking algorithm: if a node has two unmatched neighbors at the end of algorithm, then it will still be matched even when its rank is demoted to the bottom. This property allows us to form LP constraints for both the node-weighted and the unweighted oblivious matching problems. As a result, we prove that the ratio for the node-weighted case is at least 0.501512. Interestingly via the structural property, we can also improve slightly the ratio for the unweighted case to 0.526823 (from the previous best 0.523166 in SODA 2014). (2) For a bounded number of distinct edge weights, we show that ratio strictly above 0.5 can be achieved by partitioning edges carefully according to the weights, and running the (unweighted) Ranking algorithm on each part. Our analysis is based on a new primal-dual framework known as matching coverage, in which dual feasibility is bypassed. Instead, only dual constraints corresponding to edges in an optimal matching are satisfied. Using this framework we also design and analyze an algorithm for the edge-weighted online bipartite matching problem with free disposal. We prove that for the case of bounded online degrees, the ratio is strictly above 0.5. 

  • 1464. Abolmasov, Pavel
    et al.
    Poutanen, Juri
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Gamma-ray opacity of the anisotropic stratified broad-line regions in blazars2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 464, no 1, p. 152-169Article in journal (Refereed)
    Abstract [en]

    The GeV-range spectra of blazars are shaped not only by non-thermal emission processes internal to the relativistic jet but also by external pair-production absorption on the thermal emission of the accretion disc and the broad-line region (BLR). For the first time, we compute here the pair-production opacities in the GeV range produced by a realistic BLR accounting for the radial stratification and radiation anisotropy. Using photoionization modelling with the CLOUDY code, we calculate a series of BLR models of different sizes, geometries, cloud densities, column densities and metallicities. The strongest emission features in the model BLR are Ly alpha and He II Ly alpha. Contribution of recombination continua is smaller, especially for hydrogen, because Ly continuum is efficiently trapped inside the large optical depth BLR clouds and converted to Lyman emission lines and higher order recombination continua. The largest effects on the gamma-ray opacity are produced by the BLR geometry and localization of the gamma-ray source. We show that when the gamma-ray source moves further from the central source, all the absorption details move to higher energies and the overall level of absorption drops because of decreasing incidence angles between the gamma-rays and BLR photons. The observed positions of the spectral breaks can be used to measure the geometry and the location of the gamma-ray emitting region relative to the BLR. Strong dependence on geometry means that the soft photons dominating the pair-production opacity may be actually produced by a different population of BLR clouds than the bulk of the observed broad line emission.

  • 1465.
    Aboode, Adam
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Anomaly Detection in Time Series Data Based on Holt-Winters Method2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In today's world the amount of collected data increases every day, this is a trend which is likely to continue. At the same time the potential value of the data does also increase due to the constant development and improvement of hardware and software. However, in order to gain insights, make decisions or train accurate machine learning models we want to ensure that the data we collect is of good quality. There are many definitions of data quality, in this thesis we focus on the accuracy aspect.

    One method which can be used to ensure accurate data is to monitor for and alert on anomalies. In this thesis we therefore suggest a method which, based on historic values, is able to detect anomalies in time series as new values arrive. The method consists of two parts, forecasting the next value in the time series using Holt-Winters method and comparing the residual to an estimated Gaussian distribution.

    The suggested method is evaluated in two steps. First, we evaluate the forecast accuracy for Holt-Winters method using different input sizes. In the second step we evaluate the performance of the anomaly detector when using different methods to estimate the variance of the distribution of the residuals. The results indicate that the suggested method works well most of the time for detection of point anomalies in seasonal and trending time series data. The thesis also discusses some potential next steps which are likely to further improve the performance of this method.

  • 1466.
    Aboode, Adam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Utvärdering av prestanda hos ultraljudsmaskin2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The goal of this report is to try to evaluate the performance of an ultrasound scanner, which was bought by the applied physics department in 2014 for a relatively low price. By performing this evaluation we wish to answer the question if a scanner like this can be used to perform simple ultrasound examinations. Seeing that performance is such a broad concept we choose to limit ourselves in this report by focusing on the spatial resolution. The evaluation of spatial resolution was done experimentally by constructing multiple tissue-like phantoms and examining them. The results tell us that the scanner could probably be used on humans for simpler examinations such as estimation of the gestational age given that the scanner fulfils the safety requirements, something we do not investigate in this report.

  • 1467.
    Abou Jaoudeh, Elie
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Developement of Optimization Method/A Tool for RE applications in Intermittent Grids with focus on Lebanon2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Renewable energy applications require sound design and optimization of life cycle costs because they need upfront investments and as long as possible operating lifetimes are expected. Using modern tools for optimizing designs of grid-tied and autonomous plants allows investors to deploy these technologies while keeping risks within acceptable limits.

    Nevertheless in Lebanon, the grid is intermittent and the most adapted solutions are dual-mode plants that can operate autonomously and with grid-tie. There are no existent simulation models particularly adapted to optimize these applications for such a situation. The objective of this research is to suggest and test a model adapted from commercially available software that can simulate the particular conditions of Lebanon. The studied solution has a PV generator associated with a PV charge controller, lead acid battery, a dual mode inverter, and transfer switchgear and protections. The research successfully met the objective of finding a setup in HOMER 2.68beta for simulating and optimizing a PV-Battery AC plant for an intermittent grid with scheduled blackouts.

    The setup and adaptation in HOMER is made to replicate an existing reference PV-Battery plant at a public school. The measured data from this public school is used to validate the results obtained from the adapted HOMER simulation. The grid is supplied for an average of 12 hours per day at the reference site with a tariff of USD 0.1/kWh.

    After the validation process, a sensitivity analysis is performed to simulate this plant under

    1. Different grid supply hours, 12 and 18 hours of supply daily
    2. Different grid electricity prices, USD 0.1 and 0.1375 /kWh
    3. Simulation of PV plants to meet other load profiles typical of community and municipality building centers

    All the simulations cross matched 20 different PV generator sizes to 7 different battery sizes for 5 different total setups.

    The levelized cost of electricity, COE, is the main parameter used to find the optimum setups, whereas options that shortened the battery life to less than 12 years or couldn’t meet at least 90% of the required yearly load were filtered out. The COE is calculated manually since several corrections related to grid and net-metering limitations are not obtained directly from HOMER.

    The simulated results can serve as a good indicator on how the systems would perform for typical public institutions in Lebanon, given the current conditions, and knowing that the range of this study is limited to small scale institutions with consumption levels less than 30 kWh/day. Storage capacity should also be limited to 100 kWh/day of useful storage, since batteries are not the best option to use for storage capacities higher than the mentioned limit.

    The setup has a great potential for advancement and acts as a first step for Lebanon to have a specialized tool for simulating the performance of PV-battery AC plants optimized for the conditions existing in the country. Future steps could be made to improve and diversify the software to include:

    • irradiation data that come from actual data logging data from other PV sites which are installed around the whole country, almost a 100
    • financial analysis for offsetting private generation with fossil fueled gensets, which is the main backup for electricity blackouts
    • wind turbine simulations, several installations are provisioned to be completed by the end of 2012, and it would be possible to carry out a similar validation process for small wind turbines
    • pollution and other environmental costs
    • value of lost load, “VOLL”, to compare different options in parallel with COE.

  • 1468.
    Abou Zliekha, M.
    et al.
    Damascus University/Faculty of Information Technology.
    Al Moubayed, Samer
    Damascus University/Faculty of Information Technology.
    Al Dakkak, O.
    Higher Institute of Applied Science and Technology (HIAST).
    Ghneim, N.
    Higher Institute of Applied Science and Technology (HIAST).
    Emotional Audio-Visual Arabic Text to Speech2006In: Proceedings of the XIV European Signal Processing Conference (EUSIPCO), Florence, Italy, 2006Conference paper (Refereed)
    Abstract [en]

    The goal of this paper is to present an emotional audio-visual. Text to speech system for the Arabic Language. The system is based on two entities: un emotional audio text to speech system which generates speech depending on the input text and the desired emotion type, and un emotional Visual model which generates the talking heads, by forming the corresponding visemes. The phonemes to visemes mapping, and the emotion shaping use a 3-paramertic face model, based on the Abstract Muscle Model. We have thirteen viseme models and five emotions as parameters to the face model. The TTS produces the phonemes corresponding to the input text, the speech with the suitable prosody to include the prescribed emotion. In parallel the system generates the visemes and sends the controls to the facial model to get the animation of the talking head in real time.

  • 1469.
    ABOUD, STEPHANIE
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    AL MANDLAWI, LINA
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Vilken påverkan har stora readagar på produktionen inom tillverkande företag?2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Major sales days like Black Friday and Cyber Monday are today widely used and established phenomena around the world. During these days, customers are offered unique offers and strong price reductions on products. Periods like these become important for manufacturing companies as they face more demands in terms of high customer expectations and an increased demand for products.

    The purpose of this work is to investigate whether major sales days have an impact on the production within manufacturing companies. More specifically, it is investigated if the production is made more effective ahead of these days and what methods that are used to forecast demand and to avoid potential risks.

    The question is answered by conducting two studies, a literature and a field study. The literature study gives a theoretical basis for the report. The field study contributes with the practical part as it consists of interviews with two well-established manufacturing companies and also a survey for consumers to respond to. This then gives a better understanding of how companies handle major sales days and of consumers demands and expectations.

    Results from interviews shows that companies control their customers, the resellers, in a matter of how many products they should order on these sales days. Thus, they control their own demand which reduced the need to make the production more effective. In case of increased pressure on the production, companies also take other measures such as hiring extra labour. The companies do not consider the fact that they overproduce to be a problem as they are certain the products will be purchased later.

    The main results from the survey shows that the products sought by the customers during major sales days are often sold out. The majority of these customers’ lack understanding of this which indicates that there is a gap between companies supply and customers’ demands and expectations.

    A conclusion was drawn based on an analysis of the field study in relation to the literature. Companies choose to not directly affect their production or make it more effective ahead of major sales days. However, they are affected from an economic point of view as they take costly measures when faster handling within the production is needed. Furthermore, it was concluded that the customers’ actual demands and expectations are not met during these days, which suggests that companies should reevaluate some of their methods and strategies.

  • 1470.
    Aboudi, U
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Altaie, K
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Solvärme i krypgrunder2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 1471.
    Aboudi, Ula
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Altaie, Kenan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Solvärme för krypgrunder2008Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 1472. Abouelhoda, Mohamed
    et al.
    Issa, Shady
    Center for Informatics Sciences, Nile University, Giza, Egypt.
    Ghanem, Moustafa
    Tavaxy: integrating Taverna and Galaxy workflows with cloud computing support.2012In: BMC Bioinformatics, ISSN 1471-2105, E-ISSN 1471-2105, Vol. 13Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Over the past decade the workflow system paradigm has evolved as an efficient and user-friendly approach for developing complex bioinformatics applications. Two popular workflow systems that have gained acceptance by the bioinformatics community are Taverna and Galaxy. Each system has a large user-base and supports an ever-growing repository of application workflows. However, workflows developed for one system cannot be imported and executed easily on the other. The lack of interoperability is due to differences in the models of computation, workflow languages, and architectures of both systems. This lack of interoperability limits sharing of workflows between the user communities and leads to duplication of development efforts.

    RESULTS: In this paper, we present Tavaxy, a stand-alone system for creating and executing workflows based on using an extensible set of re-usable workflow patterns. Tavaxy offers a set of new features that simplify and enhance the development of sequence analysis applications: It allows the integration of existing Taverna and Galaxy workflows in a single environment, and supports the use of cloud computing capabilities. The integration of existing Taverna and Galaxy workflows is supported seamlessly at both run-time and design-time levels, based on the concepts of hierarchical workflows and workflow patterns. The use of cloud computing in Tavaxy is flexible, where the users can either instantiate the whole system on the cloud, or delegate the execution of certain sub-workflows to the cloud infrastructure.

    CONCLUSIONS: Tavaxy reduces the workflow development cycle by introducing the use of workflow patterns to simplify workflow creation. It enables the re-use and integration of existing (sub-) workflows from Taverna and Galaxy, and allows the creation of hybrid workflows. Its additional features exploit recent advances in high performance cloud computing to cope with the increasing data size and complexity of analysis.The system can be accessed either through a cloud-enabled web-interface or downloaded and installed to run within the user's local environment. All resources related to Tavaxy are available at http://www.tavaxy.org.

  • 1473.
    Aboufazeli, N.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Production Systems.
    Semere, D.T.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Production Systems.
    Ease of Reconfigurability Index: For Evaluation of the Reconfigurable Machine Tools2012Conference paper (Refereed)
    Abstract [en]

    One of the latest developments in manufacturing systems is reconfigurable manufacturing systems in which reconfigurable machine tools are the heart of such systems. The aim of application of this type of machine tool is having rapid cost-effective responsiveness to changes in new product variants or volume in manufacturing companies because of different interests, needs and desires of customers in global competitive market. The important tools to implement this kind of systems are systematic methodologies and enablers like open architecture controllers, Interface standard and comprehensive and integrated software to make the couple of limited optimized configurations of the machine tool. To choose the best configuration among proposed configuration by the software we need some evaluation methods based on smart chosen criteria to choose the best modular machine tool structure. One of the important points to choose the best configuration is ease of reconfigurability. The aim of this paper is to introduce a flexible and practical index for different products in reconfigurable manufacturing systems. This Index is defined based on two important factors: number of the changeable modules and the complexity of the interfaces including mechanical, informational and power (hydraulic, pneumatic or electrical).Generally the more number of the modules and the more complex interfaces means the more difficult to reconfigure the machine tool structure.

  • 1474.
    Aboufazeli, Nasser
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Reconfigurable Machine Tools Design Methodologies and Measuring Reconfigurability for Design Evaluation2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1475.
    Aboutalebi, Ghareman
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Optimering av fackverksstolpar med konisk eller parallell form2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 1476.
    Abouzari, Sara
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Solid solution strengthening effect on creep strength of austenitic stainless steel2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sanicro 25 is a newly developed austenitic stainless steel, designed for the next generation of Ultrasupercritical coal-fired boilers in electrical power plants. This material is applicable in reheater and superheater tubes, where the material temperature is up to 700

    °C. One of the main strengthening mechanisms in high temperature materials is solid solution strengthening. A combination of this mechanism and precipitation hardening, promotes creep strength of heat resistance materials. The aim of this work was to characterize the effects of solid solution strengthening on creep strength of Sanicro 25.Previous works has been done for effects of phosphorous in copper and also for influence of laves phase on the creep properties of CrMo alloys. The results of these two works are used and the model is adapted to austenitic stainless steel. First a Zero starting state was defined which was Alloy 316H and then the calculation was made for Sanicro 25. Thermodynamic calculations were made using DICTRA and Thermo-Calc. Elastic misfit parameter was determined using ab initio calculations. The results from the simulation in this work indicate that solutes with larger size misfit compare to the parent atoms have better solid solution strengthening effect. A decrease in the creep strength by increasing temperature has been observed which could be attributed to growth of laves phase.

  • 1477. Abou-Zleikha, Mohamed
    et al.
    Székely, Eva
    University College Dublin, Ireland.
    Cahill, Peter
    Carson-Berndsen, Julie
    Multi-level exemplar-based duration generation for expressive speech synthesis2012In: Proceedings of Speech Prosody, 2012, Vol. 2012Conference paper (Refereed)
    Abstract [en]

    The generation of duration of speech units from linguistic in- formation, as one component of a prosody model, is consid- ered to be a requirement for natural sounding speech synthesis. This paper investigates the use of a multi-level exemplar-based model for duration generation for the purposes of expressive speech synthesis. The multi-level exemplar-based model has been proposed in the literature as a cognitive model for the pro- duction of duration. The implementation of this model for dura- tion generation for speech synthesis is not straightforward and requires a set of modifications to the model and that the linguis- tically related units and the context of the target units should be taken into consideration. The work presented in this paper implements this model and presents a solution to these issues through the use of prosodic-syntactic correlated data, full con- text information of the input example and corpus exemplars. 

  • 1478.
    Abraham, Adonai
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Göranson, Max
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Att tänka utanför arket: En kartläggning över samarbeten som lett till produktinnovationer inom svensk pappers- och massaindustri 2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During the last decade has the market for printing paper begun to decline. The introduction of the smart phones and tablets quickly became a disturbing factor for the printing paper companies. This has forced the product development in the Swedish pulp and paper companies, to a greater extent, to look at more radical innovations. This requires the exploration of new applications and possibilities for the forest resource, an approach that requires expertise beyond what the companies possess internally.

    This study aims to investigate various forms of collaboration within the Swedish pulp and paper industry to identify factors that have been and are successful for product innovations. The aim has also been to investigate whether there is a change in the character of collaborations in the last 25 years. The participating companies in the study were

    SCA, Södra Cell, Holmen/MoDo, Stora Enso, BillerudKorsnäs, and Rottneros, plus some of their collaboration companies.

    The results show that the forms of collaboration in which the Swedish forest industry cooperate have changed considerably. The industry has begun to seek more cooperation with other industries, while collaboration with competitors has decreased. It seems to have become more important to regulate collaborative agreements, primarily how the intangible resources, like patents, are distributed among the participants in collaborations.

    Another conclusion is that there is a link between collaboration and the success of a firm’s product innovation. Companies are dependent on external knowledge for the success of radical innovations and a broad knowledge base is preferable to best be able to generate product innovations. External knowledge could, for example, help companies increase their understanding of other or new markets and may thus be a way to find new uses for the valuable raw material forest offers.

    Key words: radical innovation, collaboration, Swedish pulp and paper industry

  • 1479.
    Abraham, Benjamin
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Hultgren, Marcus
    KTH, School of Chemical Science and Engineering (CHE).
    Ibert, Tommie
    KTH, School of Chemical Science and Engineering (CHE).
    Möller, Johan
    KTH, School of Chemical Science and Engineering (CHE).
    Termovåtstyrka i oblekt papper2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The wet strength unbleached paper displays after heat treatment is examined in this thesis in which the authors examine the underlying mechanisms of this phenomena by experiments on differently treated paper. Two wet strength mechanism theories are examined; Lignin working as a resin versus carbonyl bonds being the main driving force behind the wet strength after thermal treatment. The authors find that using oxygen bleaching does not increase the wet strength as it would if carbonyl bonds were the main wet strength drivers, the results thus point towards the resin theory but further corroboration is needed before inference can be drawn.

  • 1480.
    Abraham, Jonatan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Strand, Anna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Reseavdrag: En analys av ett arbetsmarknadspolitiskt styrmedel ur ett hållbarhetsperspektiv2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The ability to make tax deductions on travel expenses have been present in Sweden since the late 1920s. The main purpose of the state subsidy has been to improve the mobility in the label market. However, in recent years there has been a heated debate as to if the subsidy is truly socio-economically sustainable or not. The favoritism of car users has also made the matter a question of ecological sustainability.

    The aim of this essay is to analyse and provide general knowledge of the swedish system of deductible travel expenses. The text is divided into four major parts:

    • A litterature review presenting the history of the subsidy, previous research, and the current political debate.
    • A questionnaire survey where the general public’s opinion of tax-deductible travel expenses is examined. 
    • A discussion of possible adjustments of the different parameters of the system, where the most optimal ammendment is chosen
    • An analysis of 3 different scenarios; keeping the current system, using the ammended system obtained in the calibration, and removing the system.

    From the results we could conclude that an ammended system would be noticeably more socio-economically viable and ecologically sustainable, compared with the current system. However, a complete removal of the system would be the most optimal. In addition, the questionnaire surveys results shows that the public is mostly positive to travel deductions. However, it was apparent that the views of many could shift completely, when presenting facts.

  • 1481.
    Abraham, Mark J
    Computational Proteomics Group, John Curtin School of Medical Research, Australian National University, Australia.
    Performance enhancements for GROMACS nonbonded interactions on BlueGene.2011In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 32, no 9Article in journal (Refereed)
    Abstract [en]

    Several improvements to the previously optimized GROMACS BlueGene inner loops that evaluate nonbonded interactions in molecular dynamics simulations are presented. The new improvements yielded an 11% decrease in running time for both PME and other kinds of GROMACS simulations that use nonbonded table look-ups. Some other GROMACS simulations will show a small gain.

  • 1482.
    Abraham, Mark J
    et al.
    Australian National University, Australia.
    Gready, Jill E
    Australian National University.
    Ensuring Mixing Efficiency of Replica-Exchange Molecular Dynamics Simulations2008In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 4, no 7Article in journal (Refereed)
    Abstract [en]

    We address the question of constructing a protocol for replica-exchange molecular dynamics (REMD) simulations that make efficient use of the replica space, assess whether published applications are achieving such "mixing" efficiency, and provide a how-to guide to assist users to plan efficient REMD simulations. To address our first question, we introduce and discuss three metrics for assessing the number of replica-exchange attempts required to justify the use of a replica scheme and define a "transit number" as the lower bound for the length of an efficient simulation. Our literature survey of applications of REMD simulations of peptides in explicit solvent indicated that authors are not routinely reporting sufficient details of their simulation protocols to allow readers to make independent assessments of the impact of the method on their results, particularly whether mixing efficiency has been achieved. Necessary details include the expected or observed replica-exchange probability, together with the total number of exchange attempts, the exchange period, and estimates of the autocorrelation time of the potential energy. Our analysis of cases where the necessary information was reported suggests that in many of these simulations there are insufficient exchanges attempted or an insufficiently long period between them to provide confidence that the simulation length justifies the size of the replica scheme. We suggest guidelines for designing REMD simulation protocols to ensure mixing efficiency. Two key recommendations are that the exchange period should in general be larger than 1 ps and the number of exchange attempts should be chosen to significantly exceed the transit number for the replica scheme.

  • 1483.
    Abraham, Mark J
    et al.
    Australian National University, Australia.
    Gready, Jill E
    Optimization of parameters for molecular dynamics simulation using smooth particle-mesh Ewald in GROMACS 4.52011In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 32, no 9Article in journal (Refereed)
    Abstract [en]

    Based on our critique of requirements for performing an efficient molecular dynamics simulation with the particle-mesh Ewald (PME) implementation in GROMACS 4.5, we present a computational tool to enable the discovery of parameters that produce a given accuracy in the PME approximation of the full electrostatics. Calculations on two parallel computers with different processor and communication structures showed that a given accuracy can be attained over a range of parameter space, and that the attributes of the hardware and simulation system control which parameter sets are optimal. This information can be used to find the fastest available PME parameter sets that achieve a given accuracy. We hope that this tool will stimulate future work to assess the impact of the quality of the PME approximation on simulation outcomes, particularly with regard to the trade-off between cost and scientific reliability in biomolecular applications.

  • 1484.
    Abraham, Mark James
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical & Computational Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Murtola, T.
    Schulz, R.
    Páll, Szilárd
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Smith, J. C.
    Hess, Berk
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical & Computational Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Lindahl, Erik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical & Computational Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Gromacs: High performance molecular simulations through multi-level parallelism from laptops to supercomputers2015In: SoftwareX, ISSN 2352-7110, Vol. 1-2, p. 19-25Article in journal (Refereed)
    Abstract [en]

    GROMACS is one of the most widely used open-source and free software codes in chemistry, used primarily for dynamical simulations of biomolecules. It provides a rich set of calculation types, preparation and analysis tools. Several advanced techniques for free-energy calculations are supported. In version 5, it reaches new performance heights, through several new and enhanced parallelization algorithms. These work on every level; SIMD registers inside cores, multithreading, heterogeneous CPU-GPU acceleration, state-of-the-art 3D domain decomposition, and ensemble-level parallelization through built-in replica exchange and the separate Copernicus framework. The latest best-in-class compressed trajectory storage format is supported.

  • 1485. Abraham, T.
    et al.
    Kumpulainen, A.
    Xu, Z.
    Rutland, Mark W
    KTH, Superseded Departments, Chemistry.
    Claesson, Per M.
    KTH, Superseded Departments, Chemistry.
    Masliyah, J.
    Polyelectrolyte-mediated interaction between similarly charged surfaces: Role of divalent counter ions in tuning surface forces2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 26, p. 8321-8327Article in journal (Refereed)
    Abstract [en]

    The effects of divalent salts (CaCl2, MgCl2 and BaCl2) in promoting the adsorption of weakly charged polyelectrolyte (polyacrylic acid), PAA, Mw similar to 250000 g/mol) on mica surfaces and their role in tuning the nature of interactions between such adsorbed polyelectrolyte layers were studied using the interferometric surface forces apparatus. With mica surfaces in 3 mM MgCl2 solutions at pH similar to8.0-9.0, the addition of 10 ppm PAA resulted in a long-range attractive bridging force and a short-range repulsive steric force. This force profile indicates a low surface coverage and weak adsorption. The range of the force can be related to the characteristic length scale R-G of polyelectrolyte chains using a scaling description. An increase of the PAA concentration to 50 ppm changed the attractive force profile to a monotonic, long-range repulsive interaction extending up to 600 Angstrom due to the increased surface coverage of polyelectrolyte chains on the mica surfaces. Comparison of the measured forces with a scaling mean field model suggests that the adsorbed polyelectrolyte chains are stretched, which eventually give rise to the polyelectrolyte brush like structure. When the mica surfaces were preincubated in 3 mM CaCl2 at pH similar to8.0-9.0, in contrast to the case of 3 MM MgCl2, the addition of 10 ppm PAA resulted in a more complex force profile: long-range repulsive forces extending up to 800 Angstrom followed by an attractive force regime and a second repulsive force regime at shorter separations. The long-range electrosteric forces can be attributed to strong adsorption of polyelectrolyte chains on mica surfaces (high surface coverage) which is facilitated by the presence of Ca2+ ions, while the intermediate range attractive forces can be ascribed to Ca2+ assisted bridging between adsorbed polyelectrolyte chains. Also interesting is to note various relaxation processes present in this system. In contrast to both MgCl2 and CaCl2 systems, with mica surfaces in 3 mM BaCl2 solution at pH similar to8.0-9.0, the addition of 10 ppm PAA resulted in precipitation of polyelectrolyte chains on mica surfaces, resulting in an extremely long-range monotonic repulsive force profile. In summary, our study showed that divalent counterions (Mg2+, Ca2+, and Ba2+) exhibit significantly different behavior in promoting PAA adsorption on mica surfaces, modifying and controlling various surface interactions.

  • 1486.
    Abraham, Mark James
    et al.
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Physics, Theoretical Biological Physics.
    Murtola, Teemu
    Schulz, Roland
    Pall, Szilard
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Physics, Theoretical Biological Physics.
    Smith, Jeremy C.
    Hess, Berk
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Physics, Theoretical Biological Physics.
    Lindahl, Erik
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Physics, Theoretical Biological Physics.
    GROMACS: High performance molecular simulations through multi-level parallelism from laptops to supercomputers2015In: SoftwareX, E-ISSN 2352-7110, Vol. 1-2, p. 19-25Article in journal (Refereed)
    Abstract [en]

    GROMACS is one of the most widely used open-source and free software codes in chemistry, used primarily for dynamical simulations of biomolecules. It provides a rich set of calculation types, preparation and analysis tools. Several advanced techniques for free-energy calculations are supported. In version 5, it reaches new performance heights, through several new and enhanced parallelization algorithms. These work on every level; SIMD registers inside cores, multithreading, heterogeneous CPU–GPU acceleration, state-of-the-art 3D domain decomposition, and ensemble-level parallelization through built-in replica exchange and the separate Copernicus framework. The latest best-in-class compressed trajectory storage format is supported.

  • 1487.
    Abrahamson, Lars
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Fast calculation of the dimensioning factors of the railway power supply system2007In: Computational Methods and Experimental Measurements XIII, WIT Press, 2007, Vol. 46, p. 85-95Conference paper (Refereed)
    Abstract [en]

    Because of environmental and economical reasons, in Sweden and the rest of Europe, both personal and goods transports on railway are increasing. Therefore great railway infrastructure investments are expected to come. An important part of this infrastructure is the railway power supply system. Exactly how much, when and where the traffic will increase is not known for sure. This means investment planning for an uncertain future. The more uncertain parameters, such as traffic density and weight of trains, and the further future considered, the greater the inevitable amount of cases that have to be considered. When doing simulations concerning a tremendous amount of cases, each part of the simulation model has to be computationally fast - in real life this means approximations. The two most important issues to estimate given a certain power system configuration, when planning for an electric traction system, are the energy consumption of the and and the train delays that a too weak system would cause. In this paper, some modeling suggestions of the energy consumption and the maximal train velocities are presented. Two linear, and one nonlinear model are presented and compared. The comparisons regard both computer speed and representability. The independent variables of these models are a selection of parameters describing the power system, i.e.: power system technology used on each section, and traffic intensity.

  • 1488.
    Abrahamsson, Anna-Carin
    KTH, School of Technology and Health (STH).
    Den fysiska arbetsmiljön i förskolan: utveckling, användning och granskning av en riskbedömningsmodell2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The occupational environment in preschool is becoming increasingly important. Occupational injury statistics show an increased incidence of illness among employees in education, health and care. Before action can be taken to improve the working environment, a careful assessment must be made and an action plan created. To include all possible components requires a comprehensive approach. Mapping of the physical work in Hudiksvall Municipality at all preschools provides a means by which to get an overall picture of risk areas within the preschool staff work environment.

    The aim of this work is to describe how the risk assessment model was developed and used with the ambition that it can be used in other municipalities. The model has been tested in Hudiksvall, on two occasions, in 2005 and 2010. The findings from the survey in 2010 are reported here and a comparison with 2005 is made.

    The risk assessment model is based on a survey with open questions for preschool staff combined with observation and assessment of ergonomics and safety engineer of 11 risk areas within the physical environment of the pre-school.

    The results of the survey give a clear picture of current health risks and can be used as a basis for the development of pre-school activities as well as improved maintenance of the municipal buildings. The results have also been communicated to the individual pre-schools to demonstrate their particular areas of risk.

    The combination of survey and professional assessment of several risk areas has been shown to enable a quick identification of possible causes of illness among pre-school staff. To report both positive and negative environmental factors has been an advantage. The clear method of reporting has facilitated decision-making on what if any actions to take. There is a continuing need to develop this and other instruments for the work environment survey of schools, health and social care.

  • 1489.
    Abrahamsson, Cajsa
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Miljöpåverkan, hälsopåverkan och LCC för direktdrivna kontra växellådsdrivna vindkraftverk med avseende på deras innehåll av jordartsmetaller2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Vindkraftverk med olika magnetiseringsmetoder (elektromagneter eller permanentmagneter) och maskindriftstyper (direktdrift eller växellådsdrift) undersöks i denna rapport, gällande användningen av jordartsmetaller i dessa. I första delen av rapporten studeras miljö- och hälsopåverkan från jordartsmetallindustrin i den kinesiska provinsen Baotou. Detta då Baotou står för en stor del av försörjningen av jordartsmetaller till vindkraftverksindustrin. I den andra delen av rapporten undersöks skillnaderna i livscykelkostnader mellan vindkraftverk med olika generator- och maskindriftsystem. Rapporten innehåller informationssökningar om olika aspekter som berör dessa teman såsom exempelvis olika typer av vindkraftverksgeneratorer på marknaden, miljöpåverkan från olika ämnen i jordartsmineraler, återvinning av jordartsmetaller och processen från jordartsmineral till permanent-magnet. Informationen är främst inhämtad från vindkraftverkstillverkare, tekniska rapporter och artiklar.

    I miljö- och hälsoanalysen blev slutsatsen att den negativa påverkan från jordartsmetallindustrin i Kina var för omfattande för att användningen av jordartsmetaller skulle rättfärdigas ur ett etiskt och miljömässigt perspektiv. Gruvdriften och bearbetningen av jordartsmetaller har lett till stora utsläpp av skadliga ämnen, såsom exempelvis tungmetaller och radioaktivt avfall, i provinsen Baotou. Dessa har gett allvarliga negativa konsekvenser för djur, människor och växtlighet.

    Livscykelkostnaderna för vindkraftverk med olika generatorsystem beräknades med hjälp av LCC-metoden. Slutsatsen blev att det i dagsläget inte skiljde så mycket kostnadsmässigt i valet av maskindrifttyp eller magnetiseringsmetod. Enligt beräkningar ledde användningen av permanent-magneter inte till några ekonomiska fördelar. Istället var det kostnadsförhandlingar och osäkerhet i indata som gav de största kostnadsskillnaderna. Drift och underhållskostnaderna stod för de definitivt största utgifterna och investeringskostnaderna till generatorsystemen för de näststörsta utgifterna.

  • 1490.
    Abrahamsson, Cajsa
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Carlberg, Marcus
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Studie i att ersätta kärnkraftsreaktor med biobränslealternativ2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report contains a study of replacing nuclear power with biofuel. The nuclear plant, OKG north of Oskarshamn in Sweden has been chosen and an extensive literature study about the nuclear plant has been implemented. The main aspect of this report is the availability of biofuels and whether it would be economically sustainable. Sweden’s most common biofuels are examined with regard to scope of use and potential. In the economic analysis the investments and variable costs are investigated. To conclude the work the carbon emissions due to transports of biofuel are examined.The literature study on biofuels were discussed and resulted in that the project was defined towards woodchips. Due to several aspects the project focused on replacing OKG's oldest reactor O1. Furthermore the project focused on just electricity production and combustion with CFB-boilers. Due to the Economic analysis the plant will not be profitable in the current situation. The plant profitability was examined by the net present value method. With 2011s prices, a discount rate of 6 % and an initial investment of 5.78 billion SEK the economic analysis yielded a net present value of -3.53 billion SEK. A higher price of electricity or an alternate income, for example by district heating, would be required to make the plant profitable. It would require a price of electricity of 0.55 SEK/kWh to make the plant profitable. The carbon emission due to transports of biofuel for the new plant was estimated to 6 gram/kWh and this emission was higher than that for the reactor O1.

  • 1491. Abrahamsson, Christoffer
    et al.
    Nordstierna, Lars
    Nordin, Matias
    Dvinskikh, Sergey V.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. St. Petersburg State University, Russian Federation.
    Nyden, Magnus
    Magnetic orientation of nontronite clay in aqueous dispersions and its effect on water diffusion2015In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 437, p. 205-210Article in journal (Refereed)
    Abstract [en]

    The diffusion rate of water in dilute clay dispersions depends on particle concentration, size, shape, aggregation and water-particle interactions. As nontronite clay particles magnetically align parallel to the magnetic field, directional self-diffusion anisotropy can be created within such dispersion. Here we study water diffusion in exfoliated nontronite clay dispersions by diffusion NMR and time-dependant 1H-NMR-imaging profiles. The dispersion clay concentration was varied between 0.3 and 0.7 vol%. After magnetic alignment of the clay particles in these dispersions a maximum difference of 20% was measured between the parallel and perpendicular self-diffusion coefficients in the dispersion with 0.7 vol% clay. A method was developed to measure water diffusion within the dispersion in the absence of a magnetic field (random clay orientation) as this is not possible with standard diffusion NMR. However, no significant difference in self-diffusion coefficient between random and aligned dispersions could be observed.

  • 1492.
    Abrahamsson, Erik
    KTH, School of Biotechnology (BIO).
    Changing or improving the enantioselectivity of ω-transaminase towards (R)-amines, utilizing a semi-rational design approach2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis gives a brief insight on how protein engineering is made with ω-Transaminases - enzymes that are used to create chiral amines which are included in many pharmaceuticals, fine chemicals and agrochemicals - in order to find ω-Transaminase variants that have potential for scale up in industrial processes.

    Several ways to produce (S)-amines with ω-Transaminases exist today as most characterized ω-Transaminases are (S)-selective. The (R)-selective ω-Transaminases are in the other hand rare and in 2003, only 1 (R)-selective ω-Transaminases was known. In 2012, the group of Svedendahl Humble et al. to change the enantioselectivity for the substrate 2-aminotetralin from E = 3.9 (S) to E = 63 (R) by introducing two poiny mutations (F88A/A231F) in the active site of Chromobacterium violaceum ω-Transaminase.

    By using the same variant (F88A/A231F) as a starting template, two new residues in the active site were targeted for site directed mutagenesis that hopefully would give variatns with increased E-caalue for (R)-2-aminotetralin or with changed enantiopreference, frpm (S) to (R), for other stubstrates.

    This report covers most of the steps, starting from the rational design of the active site and ends up with screening and kinetics of the possible hits using one template substrate, 1-aminotetralin.

  • 1493.
    Abrahamsson, Erik
    et al.
    KTH, School of Engineering Sciences (SCI).
    Svensson, Anton
    Design och konstruktion av experimentrigg: För planande skrov i lugnt vatten2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den här rapporten är ett kandidatsexamensarbete vid Kungliga Tekniska Högskolan,KTH, för institutionen för Marina System. Arbetet utfördes på campus i Stockholm och experiment utfördes på GIH-Badet. Kandidatsexamensarbetet genomfördes mellan Jan 2016-Juni2016.Författarna skulle vilja ge ett stort tack till handledaren Mikael Razola för bra vägledning och stöd genom hela projektet där han hela tiden sett till attprojektet rört sig framåt och i rätt riktning. Hans feedback och snabba svar närfrågor uppstått samt hans input vid möten uppskattades enormt. Karl Garme tackas också för att han delade med sig av sin erfarenhet av projektplaneringoch också såg till att projektet rörde sig framåt med sitt övergripande ansvar för kandidatsexamensarbetet. Alla medstudenter som deltagit under kursens gång vill även tackas för feedback och diskussioner under seminarierna.Ett stort tack vill också ges till Björn Magnusson som hjälpte till med CNCfräsning av modellen och Monica Norrby för hennes tid med tips och tricks i labbet vid tillverkning av modellen.

  • 1494.
    Abrahamsson, Felix
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Designing a Question Answering System in the Domain of Swedish Technical Consulting Using Deep Learning2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Question Answering systems are greatly sought after in many areas of industry. Unfortunately, as most research in Natural Language Processing is conducted in English, the applicability of such systems to other languages is limited. Moreover, these systems often struggle in dealing with long text sequences.

    This thesis explores the possibility of applying existing models to the Swedish language, in a domain where the syntax and semantics differ greatly from typical Swedish texts. Additionally, the text length may vary arbitrarily. To solve these problems, transfer learning techniques and state-of-the-art Question Answering models are investigated. Furthermore, a novel, divide-and-conquer based technique for processing long texts is developed.

    Results show that the transfer learning is partly unsuccessful, but the system is capable of perform reasonably well in the new domain regardless. Furthermore, the system shows great performance improvement on longer text sequences with the use of the new technique.

  • 1495.
    Abrahamsson, Felix
    KTH, School of Engineering Sciences (SCI).
    Microscopic Models for Trac Dynamics2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As the volume of vehicular trac has been increasing ever since its

    advent in the early 20th century, trac dynamics has become a popu-

    lar topic of study amongst physicists and mathematicians. This paper

    aims to explain di erent ways of modeling and simulating trac and

    trac dynamics. In general, modeling of trac can be divided into

    two types of models, microscopic and macroscopic. In this paper, pri-

    mary focus is on microscopic models. Examples are shown on how

    to implement simulations of so called car-following models as well as

    models based on cellular automata. Certain problems and scenarios

    regarding trac are studied as well. These include how to eciently

    distribute a roadblock, how to set the green/red time periods of a traf-

    c light in order to achieve a high trac ow or a low vehicle density,

    and how trac ow can be maximized with respect to density or other

    parameters. Results show that simulations using cellular automata

    models generally compute faster than simulations using car-following

    models. However, the results obtained from cellular automata models

    tend to be more dicult to interpret and apply to real-world sce-

    narios. A high level of stochasticity in the cellular automata models

    was also found to be necessary for the models to give applicable re-

    sults. Car-following models, on the other hand, were found to have

    the advantage of being more deterministic.

  • 1496.
    Abrahamsson, Felix
    KTH, School of Engineering Sciences (SCI).
    Microscopic Models for Trac Dynamics2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As the volume of vehicular trac has been increasing ever since its

    advent in the early 20th century, trac dynamics has become a popu-

    lar topic of study amongst physicists and mathematicians. This paper

    aims to explain di erent ways of modeling and simulating trac and

    trac dynamics. In general, modeling of trac can be divided into

    two types of models, microscopic and macroscopic. In this paper, pri-

    mary focus is on microscopic models. Examples are shown on how

    to implement simulations of so called car-following models as well as

    models based on cellular automata. Certain problems and scenarios

    regarding trac are studied as well. These include how to eciently

    distribute a roadblock, how to set the green/red time periods of a traf-

    c light in order to achieve a high trac ow or a low vehicle density,

    and how trac ow can be maximized with respect to density or other

    parameters. Results show that simulations using cellular automata

    models generally compute faster than simulations using car-following

    models. However, the results obtained from cellular automata models

    tend to be more dicult to interpret and apply to real-world sce-

    narios. A high level of stochasticity in the cellular automata models

    was also found to be necessary for the models to give applicable re-

    sults. Car-following models, on the other hand, were found to have

    the advantage of being more deterministic.

  • 1497. Abrahamsson, H
    et al.
    Hagsand, Olof
    KTH, School of Computer Science and Communication (CSC), Theoretical Computer Science, TCS.
    Marsh, Ian
    TCP over high speed variable capacity links: A simulation study for bandwidth allocation2002Conference paper (Refereed)
    Abstract [en]

     New optical network technologies provide opportunities for fast, controllable bandwidth management. These technologies can now explicitly provide resources to data paths, creating demand driven bandwidth reservation across networks where an applications bandwidth needs can be meet almost exactly. Dynamic synchronous Transfer Mode (DTM) is a gigabit network technology that provides channels with dynamically adjustable capacity. TCP is a reliable end-to-end transport protocol that adapts its rate to the available capacity. Both TCP and the DTM bandwidth can react to changes in the network load, creating a complex system with inter-dependent feedback mechanisms. The contribution of this work is an assessment of a bandwidth allocation scheme for TCP flows on variable capacity technologies. We have created a simulation environment using ns-2 and our results indicate that the allocation of bandwidth maximises TCP throughput for most flows, thus saving valuable capacity when compared to a scheme such as link over-provisioning. We highlight one situation where the allocation scheme might have some deficiencies against the static reservation of resources, and describe its causes. This type of situation warrants further investigation to understand how the algorithm can be modified to achieve performance similar to that of the fixed bandwidth case.

  • 1498.
    Abrahamsson, Johan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Danmo, Johan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    The Stabilizing Spoon: Self-stabilizing utensil to help people withimpaired motor skills2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The technology for assisting people who are functionallychallenged has improved over the recent decades. With today’stechnology, people with Parkinson’s disease can, witha device on their wrist, be able to draw pictures. Humanlimbs lost due to accidents can be replaced with bionic limbsand with help from smartphones, blind people can by audiobe informed what kind of object that appear in frontof them. These are a few examples where technology haseased everyday life for people with impaired functionality.The purpose of this thesis is to analyze how an Arduino microcontrollercan be utilized to help people with impairedmotor skills during their eating process. A prototype of astabilizing spoon was constructed to work under real circumstancesand intended to be a complement for peoplewho are in need of assistance during their eating process.To make this possible, a sensor with gyroscopes combinedwith accelerometers was used to identify which directionthe device’s handle was being tilted, as well as how fastits position was changed. Two servo motors were placedorthogonally to each other to establish a system of two degreesof freedom. With this setup, the spoon was intendedto maintain its spoon bowl in a horizontal position. Experimentalresults of the spoon showed promising performancewith some limitations.

  • 1499.
    Abrahamsson, Johanna
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Vild natur: Värden, attityder och associationer2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Modern humans are considered to have lost connection to nature and actions to reduce the separation between man and nature has been demanded. Green areas are often valued from a broad perspective and few studies have investigated the specific nature of the wild habitat. There also seem to be definitive problems and conflicts regarding the concept of "wild nature". The purpose of this report is to identify the specific values of wild nature ​​and to investigate what the concept really can include. Another purpose is to investigate attitudes and associations to wild nature and how wild nature is being worked on in planning.

    A literature study has been used as the primary method. The literature study has been supplemented with a minor case study including a documentary study, interviews and questionnaires.

    The conclusion is that wild nature offers values ​​of ecological, educational and experiential character. The ecological value is that wild nature allows biodiversity. The educational value includes aspects that help strengthen the connection to nature, which may lead to changed environmental behavior. Wild nature also has values ​​that concerns for example the experience of spiritual and reflective emotions, contributing to stress reduction and increased well-being. Moreover, wild nature is associated with large areas unaffected by humans. The same approaches are in the planning process, and the experience of wild nature is often evaluated from an ecological perspective. This means that the potential of green spaces that does not fit into the traditional image is not taken advantage of. Wild nature can also be defined based on the experience qualities related to wildness. A development towards such an approach could mean that the specific nature of the wild nature is taken advantage of. This could contribute to the increased well-being of the residents, but in the long term, a more sustainable society.

  • 1500.
    Abrahamsson, Lars
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Optimal Railroad Power Supply System Operation and Design: Detailed system studies, and aggregated investment models2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Railway power supply systems (RPSSs) differ mainly from public power systems from that the loads are moving. These moving loads are motoring trains. Trains can also be regenerating when braking and are then power sources. These loads consume comparatively much power, causing substantial voltage drops, not rarely so big that the loads are reduced. By practical reasons most RPSSs are single-phase AC or DC. Three-phase public grid power is either converted into single-phase for feeding the railway or the RPSS is compartmentalized into separate sections fed individually from alternating phase-pairs of the public grid. The latter is done in order not to overload any public grid phase unnecessarily much.

    This thesis summarizes various ways of optimally operating or designing the railway power supply system. The thesis focuses on converter-fed railways for the reasons that they are more controllable, and also has a higher potential for the future. This is also motivated in a literature-reviewing based paper arguing for the converter usage potential. Moreover, converters of some kind have to be used when the RPSS uses DC or different AC frequency than the public grid.

    The optimal operation part of this thesis is mainly about the optimal power flow controls and unit commitments of railway converter stations in HVDC-fed RPSSs. The models are easily generalized to different feeding, and they cope with regenerative braking. This part considers MINLP (mixed integer nonlinear programming) problems, and the main part of the problem is non-convex nonlinear. The concept is presented in one paper. The subject of how to model the problem formulations have been treated fully in one paper.

    The thesis also includes a conference article and a manuscript for an idea including the entire electric train driving strategy in an optimization problem considering power system and mechanical couplings over time. The latter concept is a generalized TPSS (Train Power Systems Simulator), aiming for more detailed studies, whereas TPSS is mainly for dimensioning studies. The above optimal power flow models may be implemented in the entire electric train driving strategy model.

    The optimal design part of this thesis includes two aggregation models for describing reduction in train traffic performance. The first one presented in a journal, and the second one, adapted more useful with different simulation results was presented at a conference. It also includes an early model for optimal railway power converter placements.

    The conclusions to be made are that the potential for energy savings by better operation of the railway power system is great. Another conclusion is that investment planning models for railway power systems have a high development potential. RPSS planning models are computationally more attractive, when aggregating power system and train traffic details.

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