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  • 1.
    Aarflot, Ludvig
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Implementation of High Current Measurement Technology for Automotive Applications in Programmable Logic2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    At Inmotion Technologies, a special method of measuring phase currents is usedin the high power inverters for automotive applications. This method requiresa considerable amount of control logic, currently implemented with discretelogic gates distributed over a number of integrated circuits. In this thesis, thefeasibility of replacing this with programmable logic hardware in one singlepackage is investigated.The theory behind the current measurement method as well as the operationof the discrete implementation is analysed and described. Requirements ona programmable logic device to implement this was identified and a suitabledevice chosen accordingly. A prototype was developed and tested, interfacingan existing product.Benefits in terms of cost and size are evaluated as well as required changesto the existing system and the possibility for improvements brought by such achange is analysed. Since the products in question have high requirements onfunctional safety, possible impacts in this regard are discussed.

  • 2.
    Aasberg Pipirs, Freddy
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Svensson, Patrik
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Tenancy Model Selection Guidelines2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Software as a Service (SaaS) is a subset of cloud services where a vendor provides software as a service to customers. The SaaS application is installed on the SaaS provider’s servers, and is often accessed via the web browser. In the context of SaaS, a customer is called tenant, which often is an organization that is accessing the SaaS application, but it could also be a single individual. A SaaS application can be classified into tenancy models. A tenancy model describes how a tenant’s data is mapped to the storage on the server-side of the SaaS application.By doing a research, the authors have drawn the conclusion that there is a lack of guidance for selecting tenancy models. The purpose of this thesis is to provide guidance for selecting tenancy models. The short-term-goal is to create a tenancy selection guide. The long-term-goal is to provide researchers and students with research material. This thesis provides a guidance model for selection of tenancy models. The model is called Tenancy Model Selection Guidelines (TMSG).TMSG was evaluated by interviewing two professionals from the software industry. The criteria used for evaluating TMSG were Interviewee credibility, Syntactic correctness, Semantic correctness, Usefulness and Model flexibility. In the interviews, both of the interviewees said that TMSG was in need of further refinements. Still they were positive to the achieved result.

  • 3.
    Abbas, Zainab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Al-Shishtawy, Ahmad
    RISE SICS, Stockholm, Sweden.
    Girdzijauskas, Sarunas
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS. RISE SICS, Stockholm, Sweden..
    Vlassov, Vladimir
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Short-Term Traffic Prediction Using Long Short-Term Memory Neural Networks2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Short-term traffic prediction allows Intelligent Transport Systems to proactively respond to events before they happen. With the rapid increase in the amount, quality, and detail of traffic data, new techniques are required that can exploit the information in the data in order to provide better results while being able to scale and cope with increasing amounts of data and growing cities. We propose and compare three models for short-term road traffic density prediction based on Long Short-Term Memory (LSTM) neural networks. We have trained the models using real traffic data collected by Motorway Control System in Stockholm that monitors highways and collects flow and speed data per lane every minute from radar sensors. In order to deal with the challenge of scale and to improve prediction accuracy, we propose to partition the road network into road stretches and junctions, and to model each of the partitions with one or more LSTM neural networks. Our evaluation results show that partitioning of roads improves the prediction accuracy by reducing the root mean square error by the factor of 5. We show that we can reduce the complexity of LSTM network by limiting the number of input sensors, on average to 35% of the original number, without compromising the prediction accuracy.

  • 4.
    Abbas, Zainab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Kalavri, Vasiliki
    Systems Group, ETH, Zurich, Switzerland.
    Carbone, Paris
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Vlassov, Vladimir
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Streaming Graph Partitioning: An Experimental Study2018Inngår i: Proceedings of the VLDB Endowment, ISSN 2150-8097, E-ISSN 2150-8097, Vol. 11, nr 11, s. 1590-1603Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Graph partitioning is an essential yet challenging task for massive graph analysis in distributed computing. Common graph partitioning methods scan the complete graph to obtain structural characteristics offline, before partitioning. However, the emerging need for low-latency, continuous graph analysis led to the development of online partitioning methods. Online methods ingest edges or vertices as a stream, making partitioning decisions on the fly based on partial knowledge of the graph. Prior studies have compared offline graph partitioning techniques across different systems. Yet, little effort has been put into investigating the characteristics of online graph partitioning strategies.

    In this work, we describe and categorize online graph partitioning techniques based on their assumptions, objectives and costs. Furthermore, we employ an experimental comparison across different applications and datasets, using a unified distributed runtime based on Apache Flink. Our experimental results showcase that model-dependent online partitioning techniques such as low-cut algorithms offer better performance for communication-intensive applications such as bulk synchronous iterative algorithms, albeit higher partitioning costs. Otherwise, model-agnostic techniques trade off data locality for lower partitioning costs and balanced workloads which is beneficial when executing data-parallel single-pass graph algorithms.

  • 5.
    Abbas, Zainab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Sigurdsson, Thorsteinn Thorri
    KTH.
    Al-Shishtawy, Ahmad
    RISE Res Inst Sweden, Stockholm, Sweden..
    Vlassov, Vladimir
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Programvaruteknik och datorsystem, SCS.
    Evaluation of the Use of Streaming Graph Processing Algorithms for Road Congestion Detection2018Inngår i: 2018 IEEE INT CONF ON PARALLEL & DISTRIBUTED PROCESSING WITH APPLICATIONS, UBIQUITOUS COMPUTING & COMMUNICATIONS, BIG DATA & CLOUD COMPUTING, SOCIAL COMPUTING & NETWORKING, SUSTAINABLE COMPUTING & COMMUNICATIONS / [ed] Chen, JJ Yang, LT, IEEE COMPUTER SOC , 2018, s. 1017-1025Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-time road congestion detection allows improving traffic safety and route planning. In this work, we propose to use streaming graph processing algorithms for road congestion detection and evaluate their accuracy and performance. We represent road infrastructure sensors in the form of a directed weighted graph and adapt the Connected Components algorithm and some existing graph processing algorithms, originally used for community detection in social network graphs, for the task of road congestion detection. In our approach, we detect Connected Components or communities of sensors with similarly weighted edges that reflect different states in the traffic, e.g., free flow or congested state, in regions covered by detected sensor groups. We have adapted and implemented the Connected Components and community detection algorithms for detecting groups in the weighted sensor graphs in batch and streaming manner. We evaluate our approach by building and processing the road infrastructure sensor graph for Stockholm's highways using real-world data from the Motorway Control System operated by the Swedish traffic authority. Our results indicate that the Connected Components and DenGraph community detection algorithms can detect congestion with accuracy up to approximate to 94% for Connected Components and up to approximate to 88% for DenGraph. The Louvain Modularity algorithm for community detection fails to detect congestion regions for sparsely connected graphs, representing roads that we have considered in this study. The Hierarchical Clustering algorithm using speed and density readings is able to detect congestion without details, such as shockwaves.

  • 6.
    Abdalmoaty, Mohamed
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik. KTH Royal Institute of Technology.
    Identification of Stochastic Nonlinear Dynamical Models Using Estimating Functions2019Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Data-driven modeling of stochastic nonlinear systems is recognized as a very challenging problem, even when reduced to a parameter estimation problem. A main difficulty is the intractability of the likelihood function, which renders favored estimation methods, such as the maximum likelihood method, analytically intractable. During the last decade, several numerical methods have been developed to approximately solve the maximum likelihood problem. A class of algorithms that attracted considerable attention is based on sequential Monte Carlo algorithms (also known as particle filters/smoothers) and particle Markov chain Monte Carlo algorithms. These algorithms were able to obtain impressive results on several challenging benchmark problems; however, their application is so far limited to cases where fundamental limitations, such as the sample impoverishment and path degeneracy problems, can be avoided.

    This thesis introduces relatively simple alternative parameter estimation methods that may be used for fairly general stochastic nonlinear dynamical models. They are based on one-step-ahead predictors that are linear in the observed outputs and do not require the computations of the likelihood function. Therefore, the resulting estimators are relatively easy to compute and may be highly competitive in this regard: they are in fact defined by analytically tractable objective functions in several relevant cases. In cases where the predictors are analytically intractable due to the complexity of the model, it is possible to resort to {plain} Monte Carlo approximations. Under certain assumptions on the data and some conditions on the model, the convergence and consistency of the estimators can be established. Several numerical simulation examples and a recent real-data benchmark problem demonstrate a good performance of the proposed method, in several cases that are considered challenging, with a considerable reduction in computational time in comparison with state-of-the-art sequential Monte Carlo implementations of the ML estimator.

    Moreover, we provide some insight into the asymptotic properties of the proposed methods. We show that the accuracy of the estimators depends on the model parameterization and the shape of the unknown distribution of the outputs (via the third and fourth moments). In particular, it is shown that when the model is non-Gaussian, a prediction error method based on the Gaussian assumption is not necessarily more accurate than one based on an optimally weighted parameter-independent quadratic norm. Therefore, it is generally not obvious which method should be used. This result comes in contrast to a current belief in some of the literature on the subject. 

    Furthermore, we introduce the estimating functions approach, which was mainly developed in the statistics literature, as a generalization of the maximum likelihood and prediction error methods. We show how it may be used to systematically define optimal estimators, within a predefined class, using only a partial specification of the probabilistic model. Unless the model is Gaussian, this leads to estimators that are asymptotically uniformly more accurate than linear prediction error methods when quadratic criteria are used. Convergence and consistency are established under standard regularity and identifiability assumptions akin to those of prediction error methods.

    Finally, we consider the problem of closed-loop identification when the system is stochastic and nonlinear. A couple of scenarios given by the assumptions on the disturbances, the measurement noise and the knowledge of the feedback mechanism are considered. They include a challenging case where the feedback mechanism is completely unknown to the user. Our methods can be regarded as generalizations of some classical closed-loop identification approaches for the linear time-invariant case. We provide an asymptotic analysis of the methods, and demonstrate their properties in a simulation example.

  • 7.
    Abdalmoaty, Mohamed R.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Hjalmarsson, Håkan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Application of a Linear PEM Estimator to a Stochastic Wiener-Hammerstein Benchmark Problem⁎2018Inngår i: IFAC-PapersOnLine, E-ISSN 2405-8963, Vol. 51, nr 15, s. 784-789Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The estimation problem of stochastic Wiener-Hammerstein models is recognized to be challenging, mainly due to the analytical intractability of the likelihood function. In this contribution, we apply a computationally attractive prediction error method estimator to a real-data stochastic Wiener-Hammerstein benchmark problem. The estimator is defined using a deterministic predictor that is nonlinear in the input. The prediction error method results in tractable expressions, and Monte Carlo approximations are not necessary. This allows us to tackle several issues considered challenging from the perspective of the current mainstream approach. Under mild conditions, the estimator can be shown to be consistent and asymptotically normal. The results of the method applied to the benchmark data are presented and discussed.

  • 8.
    Abdalmoaty, Mohamed R.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Hjalmarsson, Håkan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Consistent Estimators of Stochastic MIMO Wiener Models based on Suboptimal Predictors2018Konferansepaper (Fagfellevurdert)
  • 9.
    Abdalmoaty, Mohamed R.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Hjalmarsson, Håkan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Linear Prediction Error Methods for Stochastic Nonlinear Models2019Inngår i: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 105, s. 49-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The estimation problem for stochastic parametric nonlinear dynamical models is recognized to be challenging. The main difficulty is the intractability of the likelihood function and the optimal one-step ahead predictor. In this paper, we present relatively simple prediction error methods based on non-stationary predictors that are linear in the outputs. They can be seen as extensions of the linear identification methods for the case where the hypothesized model is stochastic and nonlinear. The resulting estimators are defined by analytically tractable objective functions in several common cases. It is shown that, under certain identifiability and standard regularity conditions, the estimators are consistent and asymptotically normal. We discuss the relationship between the suggested estimators and those based on second-order equivalent models as well as the maximum likelihood method. The paper is concluded with a numerical simulation example as well as a real-data benchmark problem.

    Fulltekst tilgjengelig fra 2021-04-01 16:05
  • 10.
    Abdalmoaty, Mohamed R.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Rojas, Cristian R.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Hjalmarsson, Håkan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Identification of a Class of Nonlinear Dynamical Networks⁎2018Inngår i: IFAC-PapersOnLine, E-ISSN 2405-8963, Vol. 51, nr 15, s. 868-873Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Identification of dynamic networks has attracted considerable interest recently. So far the main focus has been on linear time-invariant networks. Meanwhile, most real-life systems exhibit nonlinear behaviors; consider, for example, two stochastic linear time-invariant systems connected in series, each of which has a nonlinearity at its output. The estimation problem in this case is recognized to be challenging, due to the analytical intractability of both the likelihood function and the optimal one-step ahead predictors of the measured nodes. In this contribution, we introduce a relatively simple prediction error method that may be used for the estimation of nonlinear dynamical networks. The estimator is defined using a deterministic predictor that is nonlinear in the known signals. The estimation problem can be defined using closed-form analytical expressions in several non-trivial cases, and Monte Carlo approximations are not necessarily required. We show, that this is the case for some block-oriented networks with no feedback loops and where all the nonlinear modules are polynomials. Consequently, the proposed method can be applied in situations considered challenging by current approaches. The performance of the estimation method is illustrated on a numerical simulation example.

  • 11.
    Abdelmassih, Christian
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Container Orchestration in Security Demanding Environments at the Swedish Police Authority2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The adoption of containers and container orchestration in cloud computing is motivated by many aspects, from technical and organizational to economic gains. In this climate, even security demanding organizations are interested in such technologies but need reassurance that their requirements can be satisfied. The purpose of this thesis was to investigate how separation of applications could be achieved with Docker and Kubernetes such that it may satisfy the demands of the Swedish Police Authority.

    The investigation consisted of a literature study of research papers and official documentation as well as a technical study of iterative creation of Kubernetes clusters with various changes. A model was defined to represent the requirements for the ideal separation. In addition, a system was introduced to classify the separation requirements of the applications.

    The result of this thesis consists of three architectural proposals for achieving segmentation of Kubernetes cluster networking, two proposed systems to realize the segmentation, and one strategy for providing host-based separation between containers. Each proposal was evaluated and discussed with regard to suitability and risks for the Authority and parties with similar demands. The thesis concludes that a versatile application isolation can be achieved in Docker and Kubernetes. Therefore, the technologies can provide a sufficient degree of separation to be used in security demanding environments.

  • 12.
    Abdelmotteleb, Ibtihal
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Designing Electricity Distribution Network Charges for an Efficient Integration of Distributed Energy Resources and Customer Response2018Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    A significant transformation has been gradually taking place within the energy sector, mainly as a result of energy policies targeting environmental objectives. Consequently, the penetration of Distributed Energy Resources (DERs) has been escalating, including self-generation, demand side management, storage, and electrical vehicles. Although the integration of DERs may create technical challenges in the operation of distribution networks, it may also provide opportunities to more efficiently manage the network and defer network reinforcements. These opportunities and challenges impose the necessity of redesigning distribution network charges to incentivize efficient customer response.

    This PhD thesis focuses on the design of distribution network charges that send correct economic signals and trigger optimal responses within the context of active customers. First, a cost-reflective network charge is proposed that consists of a forward-looking locational component based on the network’s utilization level, which transmits the long-term incremental cost of network upgrades. Then, a residual cost component that recovers the remaining part of the regulated network revenues is proposed. The objective of the proposed network charge is to increase the system’s efficiency by incentivizing efficient short- and long-term customers’ reaction while ensuring network cost recovery. The Thesis presents an optimization model that simulates customers’ response to the proposed network charge in comparison to other traditional network charge designs. The model considers the operational and DER investment decisions that customers take rationally to minimize their total costs.

    Secondly, an evaluation methodology based on the Analytical Hierarchy Process technique is proposed in order to assess and compare different designs of network charges with respect to four attributes: network cost recovery, deferral of network costs, efficient customer response and recognition of side-effects on customers.

    Finally, a framework for Local Flexibility Mechanisms (LFM) is presented, complementing the proposed cost-reflective network charge. It aims to provide distribution-level coordination to mitigate unintended customer responses to network charges, by allowing customers to reveal their preferences and offer their flexibility services. It consists of a short-term LFM that utilizes customers’ flexibility in day-to-day network operation, and a long-term LFM that procures customers’ long-term flexibility to replace partially or fully network investments in network planning.

  • 13. Abedifar, V.
    et al.
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Muhammad, Ajmal
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Eshghi, M.
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Routing, modulation format, spectrum and core allocation in SDM networks based on programmable filterless nodes2018Inngår i: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An RMSCA approach based on binary particle swarm optimization is proposed for programmable filterless SDM networks, aimed at minimizing core and spectrum usage. Nearoptimal resource consumption.

  • 14. Abedifar, Vahid
    et al.
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Muhammad, Ajmal
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Eshghi, Mohammad
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Routing, Modulation and Spectrum Assignment in Programmable Networks based on Optical White Boxes2018Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 10, nr 9, s. 723-735Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Elastic optical networks (EONs) can help overcome the flexibility challenges imposed by emerging heterogeneous and bandwidth-intensive applications. Among the different solutions for flexible optical nodes, optical white box switches implemented by architecture on demand (AoD) have the capability to dynamically adapt their architecture and module configuration to the switching and processing requirements of the network traffic. Such adaptability allows for unprecedented flexibility in balancing the number of required nodal components in the network, spectral resource usage, and length of the established paths. To investigate these trade-offs and achieve cost-efficient network operation, we formulate the routing, modulation, and spectrum assignment (RMSA) problem in AoD-based EONs and propose three RMSA strategies aimed at optimizing a particular combination of these performance indicators. The strategies rely on a newly proposed internal node configuration matrix that models the structure of optical white box nodes in the network, thus facilitating hardware-aware routing of connection demands. The proposed strategies are evaluated in terms of the number of required modules and the related cost, spectral resource usage, and average path length. Extensive simulation results show that the proposed RMSA strategies can achieve remarkable cost savings by requiring fewer switching modules than the benchmarking approaches, at a favorable trade-off with spectrum usage and path length.

  • 15.
    Abedin, Ahmad
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Zurauskaite, Laura
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar. KTH.
    GOI fabrication for Monolithic 3D integrationInngår i: Artikkel i tidsskrift (Annet vitenskapelig)
  • 16.
    Abedin, Ahmad
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Zurauskaite, Laura
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Garidis, Konstantinos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Jayakumar, Ganesh
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Hellström, Per-Erik
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Östling, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Germanium on Insulator Fabrication for Monolithic 3-D Integration2018Inngår i: IEEE Journal of the Electron Devices Society, ISSN 2168-6734, Vol. 6, nr 1, s. 588-593Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A low temperature (T-max = 350 degrees C) process for Germanium (Ge) on insulator (GOI) substrate fabrication with thicknesses of less than 25 nm is reported in this paper. The process is based on a single step epitaxial growth of a Ge/SiGe/Ge stack on Si, room temperature wafer bonding and an etch-back process using Si0.5Ge0.5 as an etch-stop layer. GOI substrates with surface roughness below 0.5 nm, 0.15% tensile strain, thickness nonuniformity of less than 3 nm and residual p-type doping of less than 1016 cm(-3) were fabricated. Ge pFETs are fabricated (T-max = 600 degrees C) on the GOI wafer with 70% yield. The devices exhibit a negative threshold voltage of -0.18 V and 60% higher mobility than the SOI pFET reference devices.

  • 17.
    Abedin, Ahmad
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Zurauskaite, Laura
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Garidis, Konstantinos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Jayakumar, Ganesh
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Hellström, Per-Erik
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Östling, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    GOI fabrication for monolithic 3D integration2018Inngår i: 2017 IEEE SOI-3D-Subthreshold Microelectronics Unified Conference, S3S 2017, Institute of Electrical and Electronics Engineers (IEEE), 2018, Vol. 2018, s. 1-3Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A low temperature (Tmax=350 °C) process for Ge on insulator (GOI) substrate fabrication with thicknesses of less than 25 nm is reported in this work. The process is based on a single step epitaxial growth of a Ge/SiGe/Ge stack on Si, room temperature wafer bonding, and an etch-back process using Si0.5Ge0.5 as an etch-stop layer. Using this technique, GOI substrates with surface roughness below 0.5 nm, thickness nonuniformity of less than 3 nm, and residual p-type doping of less than 1016 cm-3 are achieved. Ge pFETs are fabricated (Tmax=600 °C) on the GOI wafer with 70% yield. The devices exhibit a negative threshold voltage of-0.18 V and 60% higher mobility than the SOI pFET reference devices.

  • 18.
    Abgrall, Corentin
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Deep learning models as advisors to execute trades on financial markets2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Recent work has shown that convolutional networks can successfully handle time series as input in various different problems. This thesis embraces this observation and introduces a new method combining machine learning techniques in order to create profitable trading strategies. The method addresses a binary classification problem: given a specific time, access to prices before this moment and an exit policy, the goal is to forecast the next price movement. The classification method is based on convolutional networks combining two major improvements: a special form of bagging and a weight propagation, to enhance the accuracy and reduce the overall variance of the model. The rolling learning and the convolutional layers are able to exploit the time dependency to strongly improve the trading strategy. The presented architecture is able to surpass the expert traders.

  • 19.
    Aboode, Adam
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Anomaly Detection in Time Series Data Based on Holt-Winters Method2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    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.

  • 20.
    Abrahamsson, Felix
    KTH, Skolan för elektroteknik och datavetenskap (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 poäng / 30 hpOppgave
    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.

  • 21.
    Abramson, Alex
    et al.
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA..
    Caffarel-Salvador, Ester
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA.;MIT, Inst Med Engn & Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Khang, Minsoo
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA..
    Dellal, David
    MIT, Inst Med Engn & Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Silverstein, David
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA..
    Gao, Yuan
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA..
    Frederiksen, Morten Revsgaard
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Vegge, Andreas
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Hubalek, Frantisek
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Water, Jorrit J.
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Friderichsen, Anders V.
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Fels, Johannes
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Kirk, Rikke Kaae
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Cleveland, Cody
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA.;Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Collins, Joy
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA..
    Tamang, Siddartha
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA..
    Hayward, Alison
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA.;MIT, Div Comparat Med, Cambridge, MA 02139 USA..
    Landh, Tomas
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Buckley, Stephen T.
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Roxhed, Niclas
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Rahbek, Ulrik
    Novo Nordisk AS, Global Res Technol, Global Drug Discovery & Device R&D, Copenhagen, Denmark..
    Langer, Robert
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA.;MIT, Inst Med Engn & Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Media Lab, Cambridge, MA 02139 USA..
    Traverso, Giovanni
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA.;MIT, Dept Mech Engn, Cambridge, MA 02139 USA.;Harvard Med Sch, Brigham & Womens Hosp, Div Gastroenterol, Boston, MA 02115 USA..
    An ingestible self-orienting system for oral delivery of macromolecules2019Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 363, nr 6427, s. 611-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biomacromolecules have transformed our capacity to effectively treat diseases; however, their rapid degradation and poor absorption in the gastrointestinal (GI) tract generally limit their administration to parenteral routes. An oral biologic delivery system must aid in both localization and permeation to achieve systemic drug uptake. Inspired by the leopard tortoise's ability to passively reorient, we developed an ingestible self-orienting millimeter-scale applicator (SOMA) that autonomously positions itself to engage with GI tissue. It then deploys milliposts fabricated from active pharmaceutical ingredients directly through the gastric mucosa while avoiding perforation. We conducted in vivo studies in rats and swine that support the applicator's safety and, using insulin as a model drug, demonstrated that the SOMA delivers active pharmaceutical ingredient plasma levels comparable to those achieved with subcutaneous millipost administration.

  • 22.
    Abramson, Alex
    et al.
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Caffarel-Salvador, Ester
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Inst Med Engn & Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Soares, Vance
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Minahan, Daniel
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Tian, Ryan Yu
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Lu, Xiaoya
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Dellal, David
    MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Inst Med Engn & Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Gao, Yuan
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Kim, Soyoung
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Wainer, Jacob
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Collins, Joy
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Tamang, Siddartha
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Hayward, Alison
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Div Comparat Med, Cambridge, MA 02139 USA..
    Yoshitake, Tadayuki
    MIT, Dept Elect Engn & Comp Sci, Cambridge, MA 02139 USA.;MIT, Elect Res Lab, Cambridge, MA 02139 USA..
    Lee, Hsiang-Chieh
    MIT, Dept Elect Engn & Comp Sci, Cambridge, MA 02139 USA.;MIT, Elect Res Lab, Cambridge, MA 02139 USA..
    Fujimoto, James
    MIT, Dept Elect Engn & Comp Sci, Cambridge, MA 02139 USA.;MIT, Elect Res Lab, Cambridge, MA 02139 USA..
    Fels, Johannes
    Global Drug Discovery, Global Res Technol, Malov, Denmark.;Novo Nordisk, Device R&D, Malov, Denmark..
    Frederiksen, Morten Revsgaard
    Global Drug Discovery, Global Res Technol, Malov, Denmark.;Novo Nordisk, Device R&D, Malov, Denmark..
    Rahbek, Ulrik
    Global Drug Discovery, Global Res Technol, Malov, Denmark.;Novo Nordisk, Device R&D, Malov, Denmark..
    Roxhed, Niclas
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik. MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Langer, Robert
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Inst Med Engn & Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Dept Mech Engn, Cambridge, MA 02139 USA.;MIT, Media Lab, Cambridge, MA 02139 USA..
    Traverso, Giovanni
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;MIT, David H Koch Inst Integrat Canc Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA.;MIT, Dept Mech Engn, Cambridge, MA 02139 USA.;Harvard Med Sch, Brigham & Womens Hosp, Div Gastroenterol, Boston, MA 02115 USA..
    A luminal unfolding microneedle injector for oral delivery of macromolecules2019Inngår i: Nature Medicine, ISSN 1078-8956, E-ISSN 1546-170X, Vol. 25, nr 10, s. 1512-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Insulin and other injectable biologic drugs have transformed the treatment of patients suffering from diabetes(1,2), yet patients and healthcare providers often prefer to use and prescribe less effective orally dosed medications(3-5). Compared with subcutaneously administered drugs, oral formulations create less patient discomfort(4), show greater chemical stability at high temperatures(6), and do not generate biohazardous needle waste(7). An oral dosage form for biologic medications is ideal; however, macromolecule drugs are not readily absorbed into the bloodstream through the gastrointestinal tract(8). We developed an ingestible capsule, termed the luminal unfolding microneedle injector, which allows for the oral delivery of biologic drugs by rapidly propelling dissolvable drug-loaded microneedles into intestinal tissue using a set of unfolding arms. During ex vivo human and in vivo swine studies, the device consistently delivered the microneedles to the tissue without causing complete thickness perforations. Using insulin as a model drug, we showed that, when actuated, the luminal unfolding microneedle injector provided a faster pharmacokinetic uptake profile and a systemic uptake > 10% of that of a subcutaneous injection over a 4-h sampling period. With the ability to load a multitude of microneedle formulations, the device can serve as a platform to orally deliver therapeutic doses of macromolecule drugs.

  • 23.
    Abrardo, Andrea
    et al.
    Univ Siena, Dipartimento Ingn Informaz, I-53100 Siena, Italy. brardo, Andrea; Moretti, Marco.
    Fodor, Gabor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Moretti, Marco
    Distributed Digital and Hybrid Beamforming Schemes With MMSE-SIC Receivers for the MIMO Interference Channel2019Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 68, nr 7, s. 6790-6804Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper addresses the problem of weighted sumrate maximization and mean squared error (MSE) minimization for the multiple-input multiple-output (MIMO) interference channel. Specifically, we consider a weighted minimum MSE architecture where each receiver employs successive interference cancellation (SIC) to separate the various received data streams and derive a hybrid beamforming scheme, where the transmitters operate with a number of radio frequency chains smaller than the number of antennas, particularly suited for millimeter-wave channels and 5G applications. To derive our proposed schemes, we first study the relationship between sum-rate maximization and weighted MSE minimization when using SIC receivers, assuming fully digital beamforming. Next, we consider the important-and, as it turns out, highly non-trivial-case where the transmitters employ hybrid digital/analog beamforming, developing a distributed joint hybrid precoding and SIC-based combining algorithm. Moreover, for practical implementation, we propose a signaling scheme that utilizes a common broadcast channel and facilitates the acquisition of channel state information, assuming minimal assistance from a central node such as a cellular base station. Numerical results show that both the proposed weighted MMSE-SIC schemes exhibit great advantages with respect to their linear counterparts in terms of complexity, feedback information, and performance.

  • 24.
    Abrardo, Andrea
    et al.
    Univ Siena, Dipartimento Ingn Informaz, I-53100 Siena, Italy..
    Fodor, Gabor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Moretti, Marco
    Univ Pisa, Dipartimento Ingn Informaz, I-50126 Pisa, Italy..
    Telek, Miklos
    Budapest Univ Technol & Econ, Dept Networked Syst & Serv, H-1117 Budapest, Hungary.;MTA BME Informat Syst Res Grp, H-1117 Budapest, Hungary..
    MMSE Receiver Design and SINR Calculation in MU-MIMO Systems With Imperfect CSI2019Inngår i: IEEE Wireless Communications Letters, ISSN 2162-2337, E-ISSN 2162-2345, Vol. 8, nr 1, s. 269-272Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The performance of the uplink of multiuser multiple input multiple output systems depends critically on the receiver architecture and on the quality of the acquired channel state information. A popular approach is to design linear receivers that minimize the mean squared error (MSE) of the received data symbols. Unfortunately, most of the literature does not take into account the presence of channel state information errors in the MSE minimization. In this letter we develop a linear minimum MSE (MMSE) receiver that employs the noisy instantaneous channel estimates to minimize the MSE, and highlight the dependence of the receiver performance on the pilot-to-data power ratio. By invoking the theory of random matrices, we calculate the users' signal-to-interference-plus-noise ratio as a function of the number of antennas and the pilot-to-data power ratio of all users. Numerical results indicate that this new linear receiver outperforms the classical mismatched MMSE receiver.

  • 25. Abu-Shaban, Zohair
    et al.
    Mehrpouyan, Hani
    M. R., Bhavani Shankar
    Ottersten, Björn
    KTH, Skolan för elektro- och systemteknik (EES), Signalbehandling. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Reduced complexity satellite broadcast receiver with interference mitigation in correlated noise2018Inngår i: International Journal of Satellite Communications and Networking, Vol. 36, nr 5, s. 402-415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The recent commercial trends towards using smaller dish antennas for satellite receivers and the growing density of broadcasting satellites necessitate the application of robust adjacent satellite interference cancellation schemes. This orbital density growth along with the wider beamwidth of a smaller dish have imposed an overloaded scenario at the satellite receiver, where the number of transmitting satellites exceeds the number of receiving elements at the dish antenna. To ensure successful operation in this practical scenario, we propose a satellite receiver that enhances signal detection from the desired satellite by mitigating the interference from neighboring satellites. Towards this objective, we propose an enhanced list-based group-wise search detection (E-LGSD) receiver under the assumption of spatially correlated additive noise. To further enhance detection performance, the proposed satellite receiver utilizes a newly designed whitening filter to remove the spatial correlation among the noise parameters, while also applying a preprocessor that maximizes the signal-to-interference-plus-noise ratio. We exploit the structure of this filter and propose a reduced complexity LGSD (RC-LGSD) receiver. Extensive simulations under practical scenarios show that the proposed receiver enhances the performance of satellite broadcast systems in the presence of adjacent satellite interference compared with existing methods. Also, under pointing error, RC-LGSD exhibits similar behavior to that of the optimum receiver

  • 26.
    Ackland, Marcus
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Investigating Adaptive Trajectories to Explore Water Plumes on Icy Moons2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates different means of introducing autonomy intodesigning spacecraft trajectories by surveying four different adaptivetrajectories. This is done using established algorithms within pathplanning and robotics, implementing trajectories based on splines andgreedy algorithms. The survey is based on real planetary data lettingthe spacecraft fly through the water plumes on Enceladus. Theseplumes are constructed using analytical models of the water plumesthat have been fitted to measurements made by Cassini during flybysover the last decade. A mission designed to probe these plumes at analtitude as low as 5 km is studied as a test scenario for the adaptive trajectories.It is found that the adaptive trajectories increase the sciencereturn at lower altitudes, both in exploring the terrain and samplingthe plume material.

  • 27.
    Ackva, Adrian
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    WinBro: A Window and Broadcast-based Parallel Streaming Graph Partitioning Framework for Apache Flink2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The past years have shown an increasing demand to process data of various kinds and size in real-time. A common representation for many real-world scenarios is a graph, which shows relations between entities, such as users of social networks or pages on the Internet. These graphs increase in size over time and can easily exceed the capacity of single machines.Graph partitioning is used to divide graphs into multiple subgraphs on different servers. Traditional partitioning techniques work in an offline manner where the whole graph is processed before partitioning. Due to the recently increased demand for real-time analysis, online partitioning algorithms have been introduced. They are able to partition a graph arriving as a stream, also referred to as a streaming graph, without any pre-processing step.The goal of a good graph partitioning algorithm is to maintain the data locality and to balance partitions’ load at the same time. Although different algorithms have proven to achieve both goals for real-world graphs, they often require to maintain a state. However, modern stream processing systems, such as Apache Flink, work with a shared-nothing architecture in a data-parallel manner. Therefore, they do not allow to exchange information along with parallel computations. These systems usually use Hash-based partitioning, that is a fast stateless technique but ignores the graph structure. Hence, it can lead to longer analysis times for streaming applications which could benefit from preserved structures.This work aims to develop a state-sharing parallel streaming graph partitioner for Apache Flink, called WinBro, implementing well-performing partitioning algorithms. In order to do this, existing streaming graph algorithms are studied for possible implementation and then integrated into WinBro.For validation, different experiments were made with real-world graphs. In these experiments, the partitioning quality, and partitioning speed were measured. Moreover, the performance of different streaming applications using WinBro was measured and compared with the default Hash-based partitioning method.Results show that the new partitioner WinBro provides better partitioning quality in terms of data locality and also higher performance for applications with requirements for locality-based input data. Nonetheless, the Hash-based partitioner shows the highest throughput and better performance for data localityagnostic streaming applications.

  • 28.
    Acquaviva, Alessandro
    et al.
    Chalmers Univ Technol, Div Elect Power Engn, S-41296 Gothenburg, Sweden..
    Wallmark, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Grunditz, Emma Arfa
    Chalmers Univ Technol, Div Elect Power Engn, S-41296 Gothenburg, Sweden..
    Lundmark, Sonja Tidblad
    Chalmers Univ Technol, Div Elect Power Engn, S-41296 Gothenburg, Sweden..
    Thiringer, Torbjorn
    Chalmers Univ Technol, Div Elect Power Engn, S-41296 Gothenburg, Sweden..
    Computationally Efficient Modeling of Electrical Machines With Cooling Jacket2019Inngår i: IEEE TRANSACTIONS ON TRANSPORTATION ELECTRIFICATION, ISSN 2332-7782, Vol. 5, nr 3, s. 618-629Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modeling of electrical machines is a multiphysics problem. Depending on the phenomena of interest and the computational time constraint, this can be done at different levels of detail. In this article, the main approaches to model the thermal behavior of electrical machines with a liquid cooled casing around the stator (often referred to as cooling jacket) are analyzed and a novel approach is presented. The proposed method aims at creating computationally efficient 3-D multiphysics models of electrical machines with liquid cooled jacket. This model is based on the assumption of a fully developed flow in the cooling jacket which allows to scale the computational fluid dynamics (CFD) simulation to 1-D. The slot with a two layer concentrated winding and potting material is modeled using a composite material comprising of both the conductors and slot filler. Similarly, a unified material is used to model the end-windings. Experimental results on a traction machine for vehicle applications are presented showing good agreement with the simulations. Also, a comparison with a 3-D CFD is presented to verify the pressure drop in the pipe bend. Finally, the model is used to simulate a dynamic load cycle, which would be computationally extremely demanding with combined 3-D CFD and thermal FEA of the machine and its cooling.

  • 29.
    Adaldo, Antonio
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Event-triggered and cloud-support control of multi-robot systems2018Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    In control of multi-robot systems, the aim is to obtain a coordinated behavior through local interactions among the robots. A multi-agent system is an abstract model of a multi-robot system. In this thesis, we investigate multi-agent systems where inter-agent communication is modeled by discrete events triggered by conditions on the internal state of the agents. We consider two models of communication. In the first model, two agents exchange information directly with each other. In the second model, all information is exchanged asynchronously over a shared repository. Four contributions on control algorithms for multi-agent systems are offered in the thesis. The first contribution is an event-triggered pinning control algorithm for a network of agents with nonlinear dynamics and time-varying topology. Pinning control is a strategy to steer the behavior of the system in a desired manner by controlling only a small fraction of the agents. We express the controllability of the network in terms of an average value of the network connectivity over time, and we show that all the agents can be driven to a desired reference trajectory. The second contribution is a control algorithm for multi-agent systems where inter-agent communication is substituted with a shared remote repository hosted on a cloud. The communication between each agent and the cloud is modeled as a sequence of events scheduled recursively by the agent. We quantify the connectivity of the network and we show that it is possible to synchronize the multi-agent system to the same state trajectory, while guaranteeing that two consecutive cloud accesses by the same agent are separated by a lower-bounded time interval. The third contribution is a family of distributed controllers for coverage and surveillance tasks with a network of mobile agents with anisotropic sensing patterns. We develop an abstract model of the environment under inspection and define a measure of the coverage attained by the sensor network. We show that the network attains nondecreasing coverage, and we characterize the equilibrium configurations of the network. The fourth contribution is a distributed, cloud-supported control algorithm for inspection of 3D structures with a network of mobile sensing agents, similar to those considered in the third contribution. We develop an abstract model of the structure to inspect and quantify the degree of completion of the inspection. We demonstrate that, under the proposed algorithm, the network is guaranteed to complete the inspection in finite time. All results presented in the thesis are corroborated by numerical simulations and sometimes by experiments with aerial robotic platforms. The experiments show that the theory and methods developed in the thesis are of practical relevance.

  • 30.
    Adaldo, Antonio
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Dimarogonas, Dimos V.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Johansson, Karl H.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Cloud-supported effective coverage of 3D structures2018Inngår i: 2018 European Control Conference, ECC 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 95-100, artikkel-id 8550377Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a distributed algorithm for cloud-supported effective coverage of 3D structures with a network of sensing agents. The structure to inspect is abstracted into a set of landmarks, where each landmark represents a point or small area of interest, and incorporates information about position and orientation. The agents navigate the environment following the proposed control algorithm until all landmarks have reached a satisfactory level of coverage. The agents do not communicate with each other directly, but exchange data through a shared cloud repository which is accessed asynchronously and intermittently. We show formally that, under the proposed control architecture, the networked agents complete the coverage mission in finite time. The results are corroborated by simulations in ROS, and experimental evaluation is in progress.

  • 31.
    Adaldo, Antonio
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik. KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, ACCESS Linnaeus Centre.
    Liuzza, Davide
    Univ Sannio, Dept Engn, I-82100 Benevento, Italy..
    Dimarogonas, Dimos V.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik. KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl H.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, ACCESS Linnaeus Centre. KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Cloud-Supported Formation Control of Second-Order Multiagent Systems2018Inngår i: IEEE Transactions on Big Data, ISSN 2325-5870, E-ISSN 2168-6750, Vol. 5, nr 4, s. 1563-1574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper addresses a formation problem for a network of autonomous agents with second-order dynamics and bounded disturbances. Coordination is achieved by having the agents asynchronously upload (download) data to (from) a shared repository, rather than directly exchanging data with other agents. Well-posedness of the closed-loop system is demonstrated by showing that there exists a lower bound for the time interval between two consecutive agent accesses to the repository. Numerical simulations corroborate the theoretical results.

  • 32.
    Adam, Jonathan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Medieteknik och interaktionsdesign, MID.
    Analyzing Function and Potential in Cuba's El Paquete: A Postcolonial Approach2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The dire state of Cuban internet connectivity has inspired local informal innovations. One such innovation is El Paquete, a weekly distribution of downloaded content spread through an informal network. Taking a postcolonial approach, I investigate through user experiences how this network operates in a resource-poor environment. This investigation articulates a model of El Paquete centered on social interactions, which inform the system’s function but also shape El Paquete’s design and role in society. Based on this model, a set of speculative design exercises probe possibilities to streamline El Paquete’s compilation, involve consumer preferences in its design directions, or act as a disruption tolerant network. In uncovering the technical possibilities of El Paquete, these designs illuminate how its current design serves Cuban communities by embodying realities and limitations of Cuban society. El Paquete’s embodiment of informal innovation serves as a call to designers to continuously rethink development design processes, centering communities and their knowledge and technical practices.

  • 33.
    Adamsson, Marcus
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Curriculum learning for increasing the performance of a reinforcement learning agent in a static first-person shooter game2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis, we trained a reinforcement learning agent using one of the most recent policy gradient methods, proximal policy optimization, in a first-person shooter game with a static player. We investigated how curriculum learning can be used to increase performance of a reinforcement learning agent. Two reinforcement learning agents were trained in two different environments. The first environment was constructed without curriculum learning and the second environment was with curriculum learning. After training the agents, the agents were placed in the same environment where we compared them based on their performance. The performance was measured by the achieved cumulative reward. The result showed that there is a difference in performance between the agents. It was concluded that curriculum learning can be used to increase the performance of a reinforcement learning agent in a first-person shooter game with a static player.

  • 34.
    Adaszynski, Wojciech
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Interactive visualization of radio waves propagation in 5G massive MIMO2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The complexity of advanced antenna techniques used in the new generation of wireless networks (5G) makes communication between experts and non-technical staff more difficult than ever. As cooperation between network vendors and network operators affects the adoption of the new standard, a need for a new tool has emerged to make technical presentations more engaging and compelling. This thesis presents an exploratory study that aims to examine various design options for an interactive visualization of radiowave propagation to be used by advanced antenna systems experts. Through a Research-oriented Design, functional and non-functional requirements were identified with the help of domain expert. Later, an interactive prototype was designed and developed using a participatory design approach. Qualitative and quantitative data was gathered through usability testing, System Usability Scale (SUS) questionnaires and semi-structured interviews conducted with 12 researchers and engineers at Ericsson AB a multinational telecommunication company. User evaluation proved that such a tool could facilitate communication between technical experts and non-technical staff. The developed prototype was considered intuitive and useful by the majority of study participants as measured by interviews and the SUS survey. Future research is encouraged to include the target audience representatives in order to measure their engagement while using the tool.

  • 35.
    Aden Hassan, Abdullahi
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Karlsson Källqvist, Rasmus
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Evaluating LoRa Physical as a Radio Link Technology for use in a Remote-Controlled Electric Switch System for a Network Bridge Radio-Node2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This report explores the design of a system for remotely switching electronics on and off within a range of at least 15 km, to be used with battery driven radio nodes for outdoor Wi-Fi network bridging. The application of the network bridges are connecting to remote networks, should Internet infrastructure fail during an emergency.The problem statement for the report was “What is a suitable radio link technology for use in a remote controlled electrical switch system and how should it best be put to use?” To answer the question, delimitation was done to exploring Low Power Wide Area Network (LPWAN) link technologies, due to their prior use within power constrained devices.Long Range-radio, abbreviated LoRa, is a LPWAN radio modulation technique and was determined to be a good candidate as a suitable link technology for the remote electrical switch system. The range of LoRa is achieved by drastically lowering the data rate of the transmission, and is suitable for battery-powered or energy harvesting devices such as those found in the field of Internet of Things.A LoRa-based transmitter and receiver pair was implemented, and measured to have a packet delivery ratio of over 95% at a distance of 2 km, measured between two bridges. Data at further distances could not be accurately determined, because of the LoRa transceiver giving faulty readings.No conclusion could be made about the suitability for using a LoRa based system to solve the problem, partially due to an improper method for testing the radio performance was used, and partially due to an inconclusive measurement result.

  • 36.
    Aditya Wardana, I Wayan Kurniawan
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Visualizing Error in Real-Time Video Streaming Data for a Monitoring System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this master thesis is to investigate the affordances and limitations of using information visualization methods to visualize errors in real-time video streaming data. The study was carried in Red Bee Media company by following several steps including user research, prototyping, and user evaluation. The user research produced design requirements and basic tasks for the prototype. The prototype had to follow the design requirements and use information visualization techniques to visualize the error data. Next, the prototype was evaluated by 5 expert users, all Red Bee Media employees with 1,5 to 3 years experience of working with the existing Red Bee Media system. The results show the prototype obtained a higher SUS score compared to the Red Bee Media monitoring system. Based on a comparison questionnaire, the prototype also had a better visualization for each basic task compared to Red Bee Media monitoring system. The comments from the user evaluation have been categorized into 4 different labels. Those labels listed several usabilities need to be focused on when developing a video monitoring system.

  • 37.
    Adlers, Jacob
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Pihl, Gustaf
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Prediction of training time for deep neural networks in TensorFlow2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Machine learning has gained a lot of interest over the past years and is now used extensively in various areas. Google has developed a framework called TensorFlow which simplifies the usage of machine learning without compromising the end result. However, it does not resolve the issue of neural network training being time consuming. The purpose of this thesis is to investigate with what accuracy training times can be predicted using TensorFlow. Essentially, how effectively one neural network in TensorFlow can be used to predict the training times of other neural networks, also in TensorFlow. In order to do this, training times for training different neural networks was collected. This data was used to create a neural network for prediction. The resulting neural network is capable of predicting training times with an average accuracy of 93.017%.

  • 38.
    Adolfsson, Alexander
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Arrhenius, Daniel
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Overseeing Intersection System for Autonomous Vehicle Guidance2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Intersections represents one of the most common accident sites in traffic today. The biggest cause of accidents is obstructed view and subpar communication between vehicles. Since autonomous vehicles rely on sensors that require a direct view intersections are some of the most complex situations. Where the potential for inter vehicular communication exists between modern vehicles, it is absent in the older generation. An overseeing intersection system can fill this function during the transition period to fully autonomous traffic. This project aimed to implement an intersection system to assist autonomous vehicles through a crossroad. The assist system’s objective was to collect and transmit data from cars close to the junction to the autonomous vehicles nearby. The concept was tested in simulations by having models traverse a crossroad to evaluate how it utilised the external information. No persistent conclusion could be made due to insufficient simulation environment and vehicle model control.

  • 39.
    Adolfsson, Fredrik
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    WebTaint: Dynamic Taint Tracking for Java-based Web Applications2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The internet is a source of information and it connects the world through a single platform. Many businesses have taken advantage of this to share information, to communicate with customers, and to create new business opportunities. However, this does not come without drawbacks as there exists an elevated risk to become targeted in attacks.

    The thesis implemented a dynamic taint tracker, named WebTaint, to detect and prevent confidentiality and integrity vulnerabilities in Java-based web applications. We evaluated to what extent WebTaint can combat integrity vulnerabilities. The possible advantages and disadvantages of using the application is introduced as well as an explication whether the application was capable of being integrated into production services.

    The results show that WebTaint helps to combat SQL Injection and Cross-Site Scripting attacks. However, there are drawbacks in the form of additional time and memory overhead. The implemented solution is therefore not suitable for time or memory sensitive domains. WebTaint could be recommended for use in test environments where security experts utilize the taint tracker to find TaintExceptions through manual and automatic attacks.

  • 40.
    Adrup, Joakim
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Visualization and Interaction with Temporal Data using Data Cubes in the Global Earth Observation System of Systems2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this study was to explore the usage of data cubes in the context of the Global Earth Observation System of Systems (GEOSS). This study investigated what added benefit could be provided to users of the GEOSS platform by utilizing the capabilities of data cubes. Data cubes in earth observation is a concept for how data should be handled and provided by a data server. It includes aspects such as flexible extraction of subsets and processing capabilities. In this study it was found that the most frequent use case for data cubes was time analysis. One of the main services provided by the GEOSS portal was the discovery and inspection of datasets. In the study a timeline interface was constructed to facilitate the exploration and inspection of datasets with a temporal dimension. The datasets were provided by a data cube, and made use of the data cubes capabilities in retrieving subsets of data along any arbitrary axis. A usability evaluation was conducted on the timeline interface to gain insight into the users requirements and user satisfaction. The results showed that the design worked well in many regards, ranking high in user satisfaction. On a number of points the study highlighted areas of improvement. Providing insight into important design limitations and challenges together with suggestions on how these could be approached in different ways.

  • 41.
    Afework, Miriam
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Medieteknik och interaktionsdesign, MID.
    Using Magic Machines to Elaborate Menstrual Self-Tracker­s for Women with Endometriosis2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Existing self-tracking tools for women concentrate on one’s general well-being and keeping track of ovulation and periods. With around 10% of women worldwide suffering from endometriosis there is an unmet need to leverage self-tracking for women whose cycles are affected by more variables. The disease is enigmatic with an unknown cause and cure and the ill­ness differs for each individual in symptoms and working treatments. It is therefore critical to understand how women can learn about their bodies and how to treat their condition. In this research I work with two sufferers to identify their secret de­sires through a workshop and a series of interviews. Results suggest that women with endometriosis could benefit from ex­perimenting with different habits and make personalized routines to suit their own needs. Finally I present design implica­tions for an existing menstrual app in the form of an add-on. The steps of the add-on tool included three steps. Firstly, choosing variables of one’s well being to track (mood, energy, pain etc.), choosing activities for one or more cycles (gluten-free diet, exercising etc.), and lastly viewing an analysis of any changes in the body.

  • 42.
    Afrem, Bassel
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Designing a Suitable Help Desk Software2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In growing help desk companies, how to handle customer requests is a mark of success. Thus, each company should have an organized system to efficiently handle the communication between the company and its customers.There are many variants of help desk service software that serve different kinds of business model. Therefore, this thesis will be a study about what types of help desk software there are and what functionalities they have, in order to reach the goal of the project which was designing a suitable help desk software for a company Amplius Field Services, based on its business model.The chosen method to solve the problem consisted of a literature study about help desk software and business models, followed by a case study about the different types of help desk software that are already developed and provided and what functions they fulfill by analyzing their pros and cons and evaluate the kind of functionalities they serve. Then, based on the performed study, a general model for a help desk software containing the most important functionalities, was provided. The provided general model should be basically applicable for all different help desk companies, with possibility to be improved by adding other functionalities as required or desired by the company itself. It is intended to companies that desire to build their own application. Finally, the general model was applied for Amplius after studying its business model.The result of the project was finding a general design of a help desk software based on the result of the case study, then, the model was applied to Amplius after setting the requirements through studying its business model’s components. This gave the tailored design for Amplius, and it was supposed to be implemented and tested, but the project time was not sufficient.

  • 43. Afzal, Hassan
    et al.
    Aouada, Djamila
    Mirbach, Bruno
    Ottersten, Björn
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Full 3D Reconstruction of Non-Rigidly Deforming Objects2018Inngår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP), ISSN 1551-6857, E-ISSN 1551-6865, Vol. 14, nr 1s, s. 24-1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we discuss enhanced full 360 degrees 3D reconstruction of dynamic scenes containing non-rigidly deforming objects using data acquired from commodity depth or 3D cameras. Several approaches for enhanced and full 3D reconstruction of non-rigid objects have been proposed in the literature. These approaches suffer from several limitations due to requirement of a template, inability to tackle large local deformations and topology changes, inability to tackle highly noisy and low-resolution data, and inability to produce online results. We target online and template-free enhancement of the quality of noisy and low-resolution full 3D reconstructions of dynamic non-rigid objects. For this purpose, we propose a view-independent recursive and dynamic multi-frame 3D super-resolution scheme for noise removal and resolution enhancement of 3D measurements. The proposed scheme tracks the position and motion of each 3D point at every timestep by making use of the current acquisition and the result of the previous iteration. The effects of system blur due to per-point tracking are subsequently tackled by introducing a novel and efficient multi-level 3D bilateral total variation regularization. These characteristics enable the proposed scheme to handle large deformations and topology changes accurately. A thorough evaluation of the proposed scheme on both real and simulated data is carried out. The results show that the proposed scheme improves upon the performance of the state-of-the-art methods and is able to accurately enhance the quality of low-resolution and highly noisy 3D reconstructions while being robust to large local deformations.

  • 44.
    Aguilar, Xavier
    et al.
    KTH, Centra, SeRC - Swedish e-Science Research Centre. KTH, Skolan för elektroteknik och datavetenskap (EECS), Beräkningsvetenskap och beräkningsteknik (CST).
    Jordan, H.
    Heller, T.
    Hirsch, A.
    Fahringer, T.
    Laure, Erwin
    KTH, Centra, SeRC - Swedish e-Science Research Centre. KTH, Skolan för elektroteknik och datavetenskap (EECS), Beräkningsvetenskap och beräkningsteknik (CST).
    An On-Line Performance Introspection Framework for Task-Based Runtime Systems2019Inngår i: 19th International Conference on Computational Science, ICCS 2019, Springer Verlag , 2019, s. 238-252Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The expected high levels of parallelism together with the heterogeneity and complexity of new computing systems pose many challenges to current software. New programming approaches and runtime systems that can simplify the development of parallel applications are needed. Task-based runtime systems have emerged as a good solution to cope with high levels of parallelism, while providing software portability, and easing program development. However, these runtime systems require real-time information on the state of the system to properly orchestrate program execution and optimise resource utilisation. In this paper, we present a lightweight monitoring infrastructure developed within the AllScale Runtime System, a task-based runtime system for extreme scale. This monitoring component provides real-time introspection capabilities that help the runtime scheduler in its decision-making process and adaptation, while introducing minimum overhead. In addition, the monitoring component provides several post-mortem reports as well as real-time data visualisation that can be of great help in the task of performance debugging.

  • 45. Aguilera, M.
    et al.
    Vanfretti, L.
    Gómez, Francisco José
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Experiences in power system multi-domain modeling and simulation with modelica & FMI: The case of gas power turbines and power systems2018Inngår i: 2018 Workshop on Modeling and Simulation of Cyber-Physical Energy Systems, MSCPES 2018 - Held as part of CPS Week, Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 1-6, artikkel-id 8405397Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The turbine-governor models that are currently used in studies of power systems include over-simplifications of turbomachinery elements. Due to the growing need to support intermittent energy resources with other energy sources like gas turbines, more detailed models including an explicit representation of the physical dynamics are attractive. In this paper, the advantages of the Modelica language and the FMI standard are considered to carry out modeling and multi-domain simulation of gas turbines with power grids, which can be used to evaluate scenarios of power variability. The work gathers preliminary results of the potential that FMUs offer to promote the exchange of turbine models by manufacturers and to conduct multi-domain simulations in several tools.

  • 46.
    Ahlberg, Carl Daniel
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Mauritz, Wera
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Modeling Far Ultraviolet Auroral Ovals at Ganymede2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Ganymede, one of Jupiters moons, differs from other moons in the Solar System as it has its own magnetic field. This rare property shapes the morphology on the existing far ultraviolet oxygen auroral ovals on the celestial body in the northern and southern hemisphere created by high energy electrons colliding into the atmosphere.With the help of the Hubble Space Telescope (HST) this phenomenon has been captured and analyzed multiple times during the past 20 years using the on-board Space Telescope Imaging Spectrograph (STIS). The ultimate goal of this project is recreating the far ultraviolet oxygen auroral emissions on Ganymede as a 3D computer model in MATLAB by using the data recovered from HST.The method used to reach this goal was to implement a model with main characteristics of the auroral ovals, project it onto a plane and then use a Cauchy distribution to filter the model. To compare the model with images from HST, a χ2-value was calculated for every pixel in each image. To further improvethe model the Nelder-Mead Simplex optimization method was applied.The project succeeded in such a way that the final model created views of the locations and the appearance of the bright spots that represent the auroral ovals around Ganymede with an accurate result in relation to the given data.

  • 47.
    Ahlberg, Sofie
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Human-in-the-Loop Control Synthesis for Multi-Agent Systems under Metric Interval Temporal Logic Specifications2019Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    With the increase of robotic presence in our homes and work environment, it has become imperative to consider human-in-the-loop systems when designing robotic controllers. This includes both a physical presence of humans as well as interaction on a decision and control level. One important aspect of this is to design controllers which are guaranteed to satisfy specified safety constraints. At the same time we must minimize the risk of not finding solutions, which would force the system to stop. This require some room for relaxation to be put on the specifications. Another aspect is to design the system to be adaptive to the human and its environment.

    In this thesis we approach the problem by considering control synthesis for multi-agent systems under hard and soft constraints, where the human has direct impact on how the soft constraint is violated. To handle the multi-agent structure we consider both a classical centralized automata based framework and a decentralized approach with collision avoidance. To handle soft constraints we introduce a novel metric; hybrid distance, which quantify the violation. The hybrid distance consists of two types of violation; continuous distance or missing deadlines, and discrete distance or spacial violation. These distances are weighed against each other with a weight constant we will denote as the human preference constant. For the human impact we consider two types of feedback; direct feedback on the violation in the form of determining the human preference constant, and direct control input through mixed-initiative control where the human preference constant is determined through an inverse reinforcement learning algorithm based on the suggested and followed paths. The methods are validated through simulations.

  • 48.
    Ahlgren, Lucas
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Marin Puentes, Angie Melissa
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Livsmedelshandel i webbutiker: En tillgänglighetsundersökning med WCAG 2.02018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Undersökningen ämnar utreda och utvärdera hur tillgängligheten är i svenska webbutiker för livsmedel. Detta med syftet att upplysa livsmedelsbranschen kring om hur tillgänglighet prioriteras idag, för att på så sätt bidra till att diskussionen kring ämnet blir mer aktiv. Undersökningen innefattade sju svenska livsmedelsbutiker på webben: Ica, Coop, Mat.se, Mathem.se, Willys, Hemköp och City Gross. I varje webbutik utvärderades tillgängligheten på tre webbsidor: startsidan, produktsidan för Arla 1 liter mellanmjölk samt kassan. Utgångspunkten för att utvärdera tillgängligheten på dessa webbsidor var webbstandarden WCAG 2.0, som är den rekommenderade standarden från W3C för att utvärdera tillgänglighet på webben. Undersökningen utfördes med hjälp av utvärderingsverktyg AChecker samt manuella utvärderingar. Resultatet visade att det skiljer mycket mellan olika webbutiker vad gällande tillgängligheten enligt tillgänglighetsstandarden WCAG 2.0. Gemensamt för alla webbutiker var att ingen av dessa uppfyllde den lägsta nivån för WCAG 2.0, nivå A. City Gross bröt mot flest riktlinjer medan Willys bröt mot minst antal riktlinjer i WCAG 2.0. Detta tyder på att tillgängligheten inte prioriteras i dessa webbutiker för livsmedel.

  • 49.
    Ahlholm, Vilma
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Hellberg, Louise
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Instagram och ekologisk hållbarhet: Hur påverkas användaren, ur ett miljöperspektiv, av ett flöde på Instagram?2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Instagram är ett socialt nätverk som är väldigt populärt i Sverige. Nätverket används för att dela information eller ta del av information i bildform från konton som användaren har valt att följa. Spridningen av information om klimatförändringarna behöver bli mer verkningsfull då människors miljöförstörande vanor är ett problem och måste ändras, men invanda beteendemönster kan vara svåra att bryta. Allmänheten behöver en knuff i rätt riktning för att leva mer klimatsmart och göra miljövänligare val.

    Studiens syftar till att, på ett kvalitativt sätt, undersöka hur ett flöde på Instagram kan påverka universitetsstudenter med fokus på klimatförändringar. Frågeställningen som uppsatsen utgår från är; Hur påverkas användaren, ur ett miljöperspektiv, av ett flöde på Instagram?

    Tillvägagångssättet för att undersöka detta innebar att deltagarna använde ett modifierat instagramkonto, och de metoderna som undersökningen använder är dagbok och individuella semistrukturerade intervjuer. Mönster i det insamlade materialet från dagböckerna och intervjuerna struktureras under olika teman och resultatet visar att studiens deltagare har påverkats på olika sätt. De har lärt sig nya saker, agerat efter tips och recept, handlat second hand, följt konton som sprider information om miljön från sitt egna instagramkonto samt haft klimatsituationen mer frekvent i huvudet. Alla dessa typer av handlingar har gemensamt att de inte är några stora livsomställningar, utan snarare enklare handlingar som är lätta att tillämpa i vardagen. Mer komplicerade handlingar, som att börja odla kryddor själv, väckte mer ett intresse och handlingen utfördes inte. Diskussionen tar upp orsakerna till de olika sätten som deltagarna har påverk och knyter an till teorier om socialt inflytande och nudging.

  • 50.
    Ahlström, Marcus
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Medieteknik och interaktionsdesign, MID.
    Broadening the Reading Experience on Mobile Devices using Tilt-based Input: An Explorative Design Study2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis is an explorative study aimed at the possibility of integrating tilt-based input to improve the reading experience on smartphones. Previous works from the early 2000s have been skeptical towards tilt-based navigation, deeming it unruly and imprecise. To investigate if today’s technology has unlocked new possibilities; two experimental reading methods were designed, created and tested iteratively on 20, respectively 18 participants. The first method is a reassessment of tilt-based auto-scrolling and the second is a novel approach comparable to tilt-based paging. Data from the reading sessions were collected quantitatively in tandem with qualitative data from post-session interviews. The results indicate good potential and a reading performance similar to the standard navigation method. The importance of accommodating people with different reading behaviours was also discussed.

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