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  • 16701.
    Ukhov, Ivan
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Marculescu, Diana
    Department of Electrical and Computer Engineering, Carnegie Mellon University, USA.
    Eles, Petru Ion
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Peng, Zebo
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Fine-Grained Long-Range Prediction of Resource Usage in Computer Clusters2017Report (Other academic)
    Abstract [en]

    In order to facilitate the development of intelligent resource managers of computer clusters, we investigate the utility of the state-of-the-art neural networks for the purpose of fine-grained long-range prediction of the resource usage in one such cluster. We consider a large data set of real-life traces and describe in detail our workflow, starting from making the data accessible for learning and finishing by predicting the resource usage of individual tasks multiple steps ahead. The experimental results indicate that such fine-grained traces as the ones considered possess a certain structure, and that this structure can be extracted by advanced machine-learning techniques and subsequently utilized for making informed predictions.

  • 16702.
    Ukhov, Ivan
    et al.
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Villani, Mattias
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Eles, Petru
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Peng, Zebo
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Statistical Analysis of Process Variation Based on Indirect Measurements for Electronic System Design2014In: 2014 19TH ASIA AND SOUTH PACIFIC DESIGN AUTOMATION CONFERENCE (ASP-DAC), New York: IEEE conference proceedings, 2014, p. 436-442Conference paper (Refereed)
    Abstract [en]

    We present a framework for the analysis of process variation across semiconductor wafers. The framework is capable of quantifying the primary parameters affected by process variation, e.g., the effective channel length, which is in contrast with the former techniques wherein only secondary parameters were considered, e.g., the leakage current. Instead of taking direct measurements of the quantity of interest, we employ Bayesian inference to draw conclusions based on indirect observations, e.g., on temperature. The proposed approach has low costs since no deployment of expensive test structures might be needed or only a small subset of the test equipments already deployed for other purposes might need to be activated. The experimental results present an assessment of our framework for a wide range of configurations.

  • 16703.
    Ukus, Buket
    et al.
    Blekinge Institute of Technology, Department of Software Engineering and Computer Science.
    Tejle, Kaarina
    Blekinge Institute of Technology, Department of Software Engineering and Computer Science.
    Application Service Provider: A viable solution seen from the customer's point of view?2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    An Application Service Provider (ASP) is a company that offers individuals or enterprises access over the Internet to applications and related services that would otherwise have to be located in their own personal or enterprise computers. The simplest way to understand the ASP concept is to think of it as "application-renting". However, the customer always owns the data. The primary purpose of this thesis is to see what kind of demands there is on an ASP solution from the customers? side. The secondary purpose is to see if the customers could consider an ASP solution if their demands were met. We have also given an explanation of the ASP concept and what factors, within the data security context, makes the solution acceptable among customers. The method we have used to find a result to our hypothesis and research questions, is that we have collected different text materials and conducted interviews. The interviewed companies where four ASP suppliers and four future possible ASP customers. The result of our investigation showed that a majority of the interviewed persons could consider an ASP solution. The result could however not be estimated and applied for the entire company, because of the variety of knowledge between the different departments. The ASP industry is clearly in the stage of maturity within the IT business, but it seems like the psychological barrier may be the strongest factor that can diminish the success of ASP.

  • 16704.
    Ul Islam, Raihan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Andersson, Karl
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Hossain, Mohammad Shahadat
    University of Chittagong, Bangladesh.
    Heterogeneous Wireless Sensor Networks Using CoAP and SMS to Predict Natural Disasters2017In: Proceedings of the 2017 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS): The 8th IEEE INFOCOM International Workshop on Mobility Management in the Networks of the Future World (MobiWorld'17),, Piscataway, NJ: IEEE Communications Society, 2017, p. 30-35Conference paper (Refereed)
    Abstract [en]

    Even in the 21 st century human is still handicapped with natural disaster. Flood is one of the most catastrophic natural disasters. Early warnings help people to take necessary steps to save human lives and properties. Sensors can be used to provide more accurate early warnings due to possibilities of capturing more detail data of surrounding nature. Recent advantages in protocol standardization and cost effectiveness of sensors it is possible to easily deploy and manage sensors in large scale. In this paper, a heterogeneous wireless sensor network is proposed and evaluated to predict natural disaster like flood. In this network CoAP is used as a unified application layer protocol for exchanging sensor data. Therefore, CoAP over SMS protocol is used for exchanging sensor data. Furthermore, the effectiveness of the heterogeneous wireless sensor network for predicting natural disaster is presented in this paper.

  • 16705.
    Ul-Abdin, Zain
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Programming of Coarse-Grained Reconfigurable Architectures2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Coarse-grained reconfigurable architectures, which offer massive parallelism coupled with the capability of undergoing run-time reconfiguration, are gaining attention in order to meet not only the increased computational demands of high-performance embedded systems, but also to fulfill the need of adaptability to functional requirements of the application. This thesis focuses on the programming aspects of such coarse-grained reconfigurable computing devices, including the relevant computation models that are capable of exposing different kinds of parallelism inherent in the application and the ability of these models to capture the adaptability requirements of the application. The thesis suggests the occam-pi language for programming of a broad class of coarse-grained reconfigurable architectures as an intermediate language; we call it intermediate, since we believe that the applicationprogramming is best done in a high-level domain-specific language. The salient properties of the occam-pi language are explicit concurrency with built-in mechanisms for interprocessorcommunication, provision for expressing dynamic parallelism, support for the expression of dynamic reconfigurations, and placement attributes. To evaluate the programming approach, a compiler framework was extended to support the language extensions in the occam-pi language, and backends were developed to target two different coarse-grained reconfigurable architectures. XPP and Ambric. The results on XPP reveal that the occam-pi based implementations produce comparable throughput to those of NML programs, while programming at a much higher level of abstraction than that of NML. Similarly the two occam-pi implementations of autofocus criterion calculation targeted to the Ambric platform outperform the CPU implementation by factors of 11-23. Thus, the results of the implemented case-studies suggest that the occam-pi language based approach simplifies the development of applications employing run-time reconfigurable devices without compromising the performance benefits.

  • 16706.
    Ul-Abdin, Zain
    et al.
    Halmstad Univ, Ctr Res Embedded Syst CERES, Halmstad, Sweden..
    Yang, Albert Mingkun
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    A Radar Signal Processing Case Study for Dataflow Programming of Manycores2017In: Journal of Signal Processing Systems, ISSN 1939-8018, E-ISSN 1939-8115, Vol. 87, no 1, p. 49-62Article in journal (Refereed)
    Abstract [en]

    The successful realization of next generation radar systems have high performance demands on the signal processing chain. Among these are advanced Active Electronically Scanned Array (AESA) radars in which complex calculations are to be performed on huge sets of data in real-time. Manycore architectures are designed to provide flexibility and high performance essential for such streaming applications. This paper deals with the implementation of compute-intensive parts of AESA radar signal processing chain in a high-level dataflow language; CAL. We evaluate the approach by targeting a commercial manycore architecture, Epiphany, and present our findings in terms of performance and productivity gains achieved in this case study. The comparison of the performance results with the reference sequential implementations executing on a state-of-the-art embedded processor show that we are able to achieve a speedup of 1.6x to 4.4x by using only 10 cores of Epiphany.

  • 16707.
    Ulfsson, Hugo
    KTH, School of Computer Science and Communication (CSC).
    Predicting Airbnb user's desired travel destinations2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to go through how to predict user’s intentions with machine learning and describe our thought process when working on the different stages of solving this type of problem. This will be done by solving Airbnb’s Kaggle problem where they wanted Kaggle users to predict where their users were most likely going to travel to based on data from their website. We go through the different choices we made while cleaning and prepairing the provided datasets and the reasoning behind these. The prediction is made using XGBoost and its boosted decision tree algorithm with several different approaches to how we go about preparing the data for training. Finally we upload the results for validation on the Kaggle challenge page and we discuss the strengths and weaknesses behind every approach and discuss what more could have been done to further improve the result.

  • 16708.
    Ulhagen, Victor
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Data visualization on Android2011Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The project discussed in this thesis was initiated by the Swedish IT company Ninetech in an effort to simplify maintenance of the company's server farm. The proposed method of simplifying maintenance was to create an Android application capable of visualizing key elements of the server farm. Since the internal information that the application should expose is of a classied nature, the whole system needs to be secured to prevent unauthorized access. This thesis describes the development of an Android application as well as a server application handling the communication between the Android application and the server farm information service.

  • 16709. Uličný, Matej
    Methods for Increasing Robustness of Deep Convolutional Neural Networks2015Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Recent discoveries uncovered flaws in machine learning algorithms such as deep neural networks. Deep neural networks seem vulnerable to small amounts of non-random noise, created by exploiting the input to output mapping of the network. Applying this noise to an input image drastically decreases classication performance. Such image is referred to as an adversarial example. The purpose of this thesis is to examine how known regularization/robustness methods perform on adversarial examples. The robustness methods: dropout, low-pass filtering, denoising autoencoder, adversarial training and committees have been implemented, combined and tested. For the well-known benchmark, the MNIST (Mixed National Institute of Standards and Technology) dataset, the best combination of robustness methods has been found. Emerged from the results of the experiments, ensemble of models trained on adversarial examples is considered to be the best approach for MNIST. Harmfulness of the adversarial noise and some robustness experiments are demonstrated on CIFAR10 (The Canadian Institute for Advanced Research) dataset as well. Apart from robustness tests, the thesis describes experiments with human classification performance on noisy images and the comparison with performance of deep neural network.

  • 16710.
    Uličný, Matej
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Lundström, Jens
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Byttner, Stefan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Robustness of Deep Convolutional Neural Networks for Image Recognition2016In: Intelligent Computing Systems: First International Symposium, ISICS 2016, Mérida, México, March 16-18, 2016, Proceedings / [ed] Anabel Martin-Gonzalez, Victor Uc-Cetina, Cham: Springer, 2016, Vol. 597, p. 16-30Conference paper (Refereed)
    Abstract [en]

    Recent research has found deep neural networks to be vulnerable, by means of prediction error, to images corrupted by small amounts of non-random noise. These images, known as adversarial examples are created by exploiting the input to output mapping of the network. For the MNIST database, we observe in this paper how well the known regularization/robustness methods improve generalization performance of deep neural networks when classifying adversarial examples and examples perturbed with random noise. We conduct a comparison of these methods with our proposed robustness method, an ensemble of models trained on adversarial examples, able to clearly reduce prediction error. Apart from robustness experiments, human classification accuracy for adversarial examples and examples perturbed with random noise is measured. Obtained human classification accuracy is compared to the accuracy of deep neural networks measured in the same experimental settings. The results indicate, human performance does not suffer from neural network adversarial noise.

  • 16711.
    Ullah, Farooq Kifayat
    Blekinge Institute of Technology, School of Engineering.
    New Generation of Vibration Experiments Remotely Controlled Over the Internet:Development of Labview based Spectrum Analyzer and Interface.2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This thesis is part of the on going work at BTH (Blekinge Technical University) to develop a remote lab for Sound and Vibration Experiments. The aim of this undertaking is to develop a Spectrum Analyzer that can simultaneously take inputs from 10 sensors and be able to measure the Power Spectral Density, Cross correlation, Frequency Response Functions (FRF) and coherence. The Interface and analysis algorithms are developed inLabview programming language. The thesis starts by introducing the overall aim of the project and its scope, the place of this particular thesis in the whole picture and the algorithms used for analysis are introduced. In the second part of the thesis the development of the software is explained and the main aim is to thoroughly document the software. This part of the thesis explains Labview programming concepts in detail to make it easier for other students who want to undertake theses to continue this work and who may not have experience of Labview programming.Two versions of the spectrum analyzer were developed. The third part explains theexperimental set up and results obtained and compares measurements to those obtained using other spectrum analyzers. An accurate Spectrum Analyzer Virtual Instrument has been developed and tested during this thesis project and it can be used as a component of the proposed Sound and vibration analysis laboratory and also for general Spectral Analysis tasks.

  • 16712.
    Ullah, Ikram
    KTH, School of Computer Science and Communication (CSC), Computational Biology, CB. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Probabilistic Models for Species Tree Inference and Orthology Analysis2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A phylogenetic tree is used to model gene evolution and species evolution using molecular sequence data. For artifactual and biological reasons, a gene tree may differ from a species tree, a phenomenon known as gene tree-species tree incongruence. Assuming the presence of one or more evolutionary events, e.g., gene duplication, gene loss, and lateral gene transfer (LGT), the incongruence may be explained using a reconciliation of a gene tree inside a species tree. Such information has biological utilities, e.g., inference of orthologous relationship between genes.

    In this thesis, we present probabilistic models and methods for orthology analysis and species tree inference, while accounting for evolutionary factors such as gene duplication, gene loss, and sequence evolution. Furthermore, we use a probabilistic LGT-aware model for inferring gene trees having temporal information for duplication and LGT events.

    In the first project, we present a Bayesian method, called DLRSOrthology, for estimating orthology probabilities using the DLRS model: a probabilistic model integrating gene evolution, a relaxed molecular clock for substitution rates, and sequence evolution. We devise a dynamic programming algorithm for efficiently summing orthology probabilities over all reconciliations of a gene tree inside a species tree. Furthermore, we present heuristics based on receiver operating characteristics (ROC) curve to estimate suitable thresholds for deciding orthology events. Our method, as demonstrated by synthetic and biological results, outperforms existing probabilistic approaches in accuracy and is robust to incomplete taxon sampling artifacts.

    In the second project, we present a probabilistic method, based on a mixture model, for species tree inference. The method employs a two-phase approach, where in the first phase, a structural expectation maximization algorithm, based on a mixture model, is used to reconstruct a maximum likelihood set of candidate species trees. In the second phase, in order to select the best species tree, each of the candidate species tree is evaluated using PrIME-DLRS: a method based on the DLRS model. The method is accurate, efficient, and scalable when compared to a recent probabilistic species tree inference method called PHYLDOG. We observe that, in most cases, the analysis constituted only by the first phase may also be used for selecting the target species tree, yielding a fast and accurate method for larger datasets.

    Finally, we devise a probabilistic method based on the DLTRS model: an extension of the DLRS model to include LGT events, for sampling reconciliations of a gene tree inside a species tree. The method enables us to estimate gene trees having temporal information for duplication and LGT events. To the best of our knowledge, this is the first probabilistic method that takes gene sequence data directly into account for sampling reconciliations that contains information about LGT events. Based on the synthetic data analysis, we believe that the method has the potential to identify LGT highways.

  • 16713.
    Ullah, Ikram
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ayaz, Muhammad
    Blekinge Institute of Technology, School of Computing.
    Investigation of Customer-Driven Innovation2013Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Context:- Software companies have changed their strategies from “innovating for customers” and “innovating with customers” to innovating “by customers” which is also known as customer-driven innovation. Actually, companies move toward customer-driven innovation programs because they need to collect as many ideas as possible from suitable customers to ensure their global competitiveness and set the stage for profitable growth. As customer-driven innovation is comparatively a new trend, the objective of our research is to explore its status in the new era of software development. Objectives:- The main aim of our study is to investigate customer-driven innovation in the modern era of software development. It also explores the motives, benefits, communication channels and barriers between customers and software companies to cooperate with each other. Methods:- Systematic Literature Review (SLR) and industrial interviews are two basic types of data collection methods which are utilized to accomplish the objectives of our study. Then qualitative data analysis software is used to perform thematic analysis (Grounded Theory) in order to draw conclusions and highlight useful information from the collected data. Results:- Based on the SLR and interviews result the conclusion was made that there are different types of motives and benefits for company and customer to cooperate with each other during idea generation stage of product and service innovations. We identified various types of activities and communication channels in the context of customer-driven innovation. In addition, we identified different types of barriers that can limit the cooperation between company and customers. Conclusions:- The comparison between theory and practice explored most important motive and benefit for company and customers to cooperate with each other during ideation process of product and service innovation. It also identified most significant activities and communication channels for idea generation in the context of customer-driven innovation. In addition, we identified most common barriers which prevent company and customers to cooperate with each other during ideation process.

  • 16714. Ullah, Ikram
    et al.
    Sjöstrand, Joel
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Stockholm University, Science for Life Laboratory (SciLifeLab).
    Andersson, Peter
    Sennblad, Bengt
    Lagergren, Jens
    Integrating Sequence Evolution into Probabilistic Orthology Analysis2015In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 64, no 6, p. 969-982Article in journal (Refereed)
    Abstract [en]

    Orthology analysis, that is, finding out whether a pair of homologous genes are orthologs - stemming from a speciation - or paralogs - stemming from a gene duplication - is of central importance in computational biology, genome annotation, and phylogenetic inference. In particular, an orthologous relationship makes functional equivalence of the two genes highly likely. A major approach to orthology analysis is to reconcile a gene tree to the corresponding species tree, (most commonly performed using the most parsimonious reconciliation, MPR). However, most such phylogenetic orthology methods infer the gene tree without considering the constraints implied by the species tree and, perhaps even more importantly, only allow the gene sequences to influence the orthology analysis through the a priori reconstructed gene tree. We propose a sound, comprehensive Bayesian Markov chain Monte Carlo-based method, DLRSOrthology, to compute orthology probabilities. It efficiently sums over the possible gene trees and jointly takes into account the current gene tree, all possible reconciliations to the species tree, and the, typically strong, signal conveyed by the sequences. We compare our method with PrIME-GEM, a probabilistic orthology approach built on a probabilistic duplication-loss model, and MRBAYESMPR, a probabilistic orthology approach that is based on conventional Bayesian inference coupled with MPR. We find that DLRSOrthology outperforms these competing approaches on synthetic data as well as on biological data sets and is robust to incomplete taxon sampling artifacts.

  • 16715.
    ULLAH, IRSHAD
    et al.
    Blekinge Institute of Technology, School of Computing.
    REHMAN, SHOAIB UR
    Blekinge Institute of Technology, School of Computing.
    Analysis of Black Hole Attack on MANETs Using Different MANET Routing Protocols2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Wireless networks are gaining popularity to its peak today, as the users want wireless connectivity irrespective of their geographic position. There is an increasing threat of attacks on the Mobile Ad-hoc Networks (MANET). Black hole attack is one of the security threat in which the traffic is redirected to such a node that actually does not exist in the network. It’s an analogy to the black hole in the universe in which things disappear. The node presents itself in such a way to the node that it can attack other nodes and networks knowing that it has the shortest path. MANETs must have a secure way for transmission and communication which is quite challenging and vital issue. In order to provide secure communication and transmission, researcher worked specifically on the security issues in MANETs, and many secure routing protocols and security measures within the networks were proposed. Previously the works done on security issues in MANET were based on reactive routing protocol like Ad-Hoc On Demand Distance Vector (AODV). Different kinds of attacks were studied, and their effects were elaborated by stating how these attacks disrupt the performance of MANET. The scope of this thesis is to study the effects of Black hole attack in MANET using both Proactive routing protocol i.e. Optimized Link State Routing (OLSR) and Reactive routing protocol Ad-Hoc On Demand Distance Vector (AODV). Comparative analysis of Black Hole attack for both protocols is taken into account. The impact of Black Hole attack on the performance of MANET is evaluated finding out which protocol is more vulnerable to the attack and how much is the impact of the attack on both protocols. The measurements were taken in the light of throughput, end-to-end delay and network load. Simulation is done in Optimized Network Engineering Tool (OPNET).

  • 16716.
    Ullah, Malik Imran
    et al.
    Blekinge Institute of Technology, School of Computing.
    Zaidi, Waqar Ali
    Blekinge Institute of Technology, School of Computing.
    Quality Assurance Activities in Agile: Philosophy to Practice2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Quality assurance activities, in software development, are the backbone of whole project. These activities are not only responsible of product quality, but also for process quality. In conventional software development QA is a separate group of QA experts. As the trends of software development moved towards agile development, QA activities also got changed. In agile development most of these activities are performed by developers. Close people collaboration, onsite customer and Test Driven Development are the approaches in agile development to achieve better product quality. In this thesis we have presented the philosophical as well as practical angle QA in agile development. Mindset of agile development revolves around product quality but there is much work to be done to impart quality of process in agile development to get it standardized and more organized. QA activities remain centric and focused to testing. Practices like SPI and following some standards are lacking in agile methodologies. In this thesis we have proposed to inject an extra layer of QA in agile projects. Purpose of injecting and extra layer, is to use the knowledge of QA experts to achieve quality in development process that will result in higher level of product quality.

  • 16717.
    Ullah, Malik Zaka
    Blekinge Institute of Technology, School of Computing.
    An Analysis of Bluetooth Technology,Features,Future and Security2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In this thesis I present my analysis on various aspects of Bluetooth wireless technology. The Bluetooth technology is relatively new as compared to other technologies and there is huge potential of its growth and practical application. Therefore during in this thesis I try to analysis the current status of this technology and issue which are related to this technology. The first section introduces Bluetooth technology, in which I discussed the architecture of Bluetooth and different terminologies of Bluetooth. In the same section I presented the comparison of Bluetooth with other communication technologies. The main questions I hope to answer in this thesis and also discuss the methodology I employed. The subsequent sections discuss the core technical features and issues of security and interoperability of Bluetooth. In these sections I identify the key aspects of Bluetooth that make it standout from other wireless technologies and point out certain shortcomings of this technology. During this I went through different aspect of Bluetooth technology. Subsequently I present my analysis of the market player’s and user’s perspectives and identify the main drivers and barriers of Bluetooth from a business point of view. Towards the end of this thesis I discuss how this technology can be used to provide some attractive solutions. I demonstrate my ideas by discussing how certain services can be used in future in different scenarios. In my proposed solution I discussed the possibilities and advantages of using Bluetooth technology in university campus to perform different routine tasks and this will beneficial for the university both student and teachers. Keywords: Personal Area Networks, Asynchronous connection Link, Ultra Wide Band, Special Interest group, Bluetooth Technology

  • 16718.
    Ullah, Muhammad
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ahmad, Waqar
    Blekinge Institute of Technology, School of Computing.
    Evaluation of Routing Protocols in Wireless Sensor Networks2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The evolution of wireless communication and circuit technology has enabled the development of an infrastructure consists of sensing, computation and communication units that makes administrator capable to observe and react to a phenomena in a particular environment. The building block of such an infrastructure is comprised of hundreds or thousands of small, low cost, multifunctional devices which have the ability to sense compute and communicate using short range transceivers known as sensor nodes. The interconnection of these nodes forming a network called wireless sensor network (WSN). The low cost, ease of deployment, ad hoc and multifunctional nature has exposed WSNs an attractive choice for numerous applications. The application domain of WSNs varies from environmental monitoring, to health care applications, to military operation, to transportation, to security applications, to weather forecasting, to real time tracking, to fire detection and so on. By considering its application areas WSN can be argue as a traditional wired or wireless network. But in reality, these networks are comprised of battery operated tiny nodes with limitations in their computation capabilities, memory, bandwidth, and hardware resulting in resource constrained WSN. The resource constrained nature of WSN impels various challenges in its design and operations degrading its performance. On the other hand, varying numbers of applications having different constraints in their nature makes it further challenging for such resources constrained networks to attain application expectations. These challenges can be seen at different layer of WSNs starting from physical layer up to application layer. At routing layer, routing protocols are mainly concerned with WSN operation. The presence of these challenges affects the performance of routing protocols resulting in overall WSN performance degradation. The aim of this study is to identify the performance challenges of WSN and analyze their impact on the performance of routing protocols. For this purpose a thorough literature study is performed to identify the issues affecting the routing protocols performance. Then to validate the impact of identified challenges from literature, an empirical study has been conducted by simulating different routing protocols, taking into consideration these challenges and results are shown. On the basis of achieved results from empirical study and literature review recommendations are made for better selection of protocol regarding to application nature in the presence of considered challenges.

  • 16719.
    Ullah, Muhammad
    et al.
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Wac, Katarzyna
    Blekinge Institute of Technology, School of Computing.
    On the ambiguity of Quality of Service and Quality of Experience requirements for eHealth services2012Conference paper (Refereed)
    Abstract [en]

    The use of end-to-end communication systems as a medium of delivery for electronic healthcare (eHealth) services is considered to be uncertain, with respect to its reliability leading to hesitation in acceptance of such services. There exist different influential dimensions that pose stringent requirements on end-to-end communication systems, influence user perception and might hinder user acceptance. The later is referred to as Qualityof Experience (QoE), which among others depends on the Quality of Service (QoS) of the end-to-end communication system. QoE is considered as a key component determining user acceptance. This paper identifies and analyzes characteristics of a set of eHealth services and the influential dimensions resulting in different QoS requirements and potential impact of QoS on QoE. It highlights the role of QoS and QoE for acceptance of these services. The issue of non-uniform views regarding QoS parameter specifications and related requirements, clinically acceptable thresholds and their qualitative representation in eHealth literature is reviewed and presented.

  • 16720.
    Ullberg, Johan
    et al.
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Johnson, Pontus
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Empirical assessment of the accuracy of an interoperability prediction language2016In: Information Systems Frontiers, ISSN 1387-3326, E-ISSN 1572-9419, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Interoperability, defined as the satisfaction of a communication need between two or more actors, is an important aspect in many phases of an enterprise’s development. Mastering the field of interoperability is a daunting task so aid in predicting interoperability can be of great benefit. Formalisms capable of such predictions of future information system architectures are however sparse, and when employed, it is essential that the prediction is accurate. In this paper, a previously proposed interoperability modelling and prediction language is subjected to case testing and evaluated toward interoperability predictions made by practitioners and experts in the field. The results show that although there are some areas not currently covered by the framework, in general, it performs better than the intended users, and would thereby provide additional support in various development and design contexts.

  • 16721.
    Ullberg, Jonas
    Örebro University, School of Science and Technology.
    2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Public demand for intelligent services in their home environments can be expected to grow in the near future once the required technology becomes more widely available and mature. Many intelligent home services cannot be provided in a purely reactive fashion though since they require contextual knowledge about the environment and most importantly the activities the residents are engaged in at any given time. This poses a problem since information about a human’s behavior is not easily accessible and has to be recognized from aggregated sensor data in most cases. Numerous activity recognition techniqueshave been studied in the literature. In this thesis we focus on one such technique which takes a temporal reasoning approach to activity recognition, namely recognizing activities by planning for them with a temporal planner. OMPS is an example of such a planner that has been used in previous work to recognize activities of humans in domestic environments. An important requirement for monitoring activities in a real world application is the ability to do so continuously and reliably. Two shortcomings in the previous approach hindered OMPS’s capability to meet this requirement, namely maintaining the performance of the activity recognition over long monitoring horizons, and ensuring future temporal consistency of recognized activities. This thesis will define the two problems, detail their solutions, and finally evaluate the modified system with the corresponding changes implemented.

  • 16722.
    Ullberg, Jonas
    et al.
    Örebro University, School of Science and Technology.
    Coradeschi, Silvia
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    On-line ADL recognition with prior knowledge2010In: STAIRS 2010: proceedings of the fifth Starting AI Researchers' Symposium / [ed] Thomas Ågotnes, Amsterdam: IOS Press, 2010, p. 354-366Conference paper (Refereed)
    Abstract [en]

    This paper addresses the problem of recognizing activities of daily living. The novelty lies in the use of an existing knowledge base (ConceptNet) to introduce prior knowledge into the system in order to reduce the amount of learning required to deploy the system in a real environment. The use of household objects is central in the recognition of activities that are being performed, and we attach semantic meaning to both the objects and activities that are being recognized. The paper describes a framework which is specifically geared towards realizing activity recognition systems which leverage prior knowledge. A preliminary implementation of a neural network based recognition system built on this framework is shown, and the added value of prior knowledge is evaluated through the use of various data sets.

  • 16723.
    Ullberg, Jonas
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    A customizable approach for monitoring activities of elderly users in their homes2014In: Activity Monitoring by Multiple Distributed Sensing: Second International Workshop, AMMDS 2014, Stockholm, Sweden, August 24, 2014, Revised Selected Papers / [ed] Mazzeo, Pier Luigi and Spagnolo, Paolo and Moeslund, Thomas B., Cham: Springer International Publishing , 2014, p. 13-25Conference paper (Refereed)
    Abstract [en]

    This paper presents an implemented context recognition system that enables caregivers to query and visualize daily activities of elderly who live in their own homes. The system currently serves several homes across Europe and provides caregivers with the ability to correlate activities with specific health indicators. The system also allows to define conditions under which alarms should be raised.

  • 16724.
    Ullberg, Jonas
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Towards continuous activity monitoring with temporal constraints2009Conference paper (Refereed)
    Abstract [en]

    This paper focuses on a temporal reasoning approach for human activity recognition. Specifically, we show how search and temporal propagation are used to enable long term and continuous activity recognition. Two specific issues are addressed, namely maintaining performance over long monitoring horizons and ensuring future temporal consistency of recognized activities. We propose a complete search algorithm for activity recognition which addresses these issues, in which an admissible pruning technique allows improved performance. We show a sufficient condition for guaranteeing future admissibility, and experimental results which test the limits and practical applicability of the system are presented.

  • 16725.
    Ullberg, Jonas
    et al.
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Propagating temporal constraints on sets of intervals2012In: ICAPS Workshop on Planning and Scheduling with Timelines, 2012, p. 25-32Conference paper (Refereed)
    Abstract [en]

    In this paper we propose a method of propagating quantitative Allen interval constraints on sets of intervals defined by polygons in a two dimensional space. The method is used to solve the problem of inferring timelines of human activities from timelines representing traces of sensor data. The main advantage of this method over others is that it allows a more general description of the events that the intervals are taken to reflect during inference. This paper deals with the algorithmic issues underlying the timeline recognition process. In this context, we compare the performance of our method to that of a state of the art approach based on classical temporal constraint reasoning techniques (Dousson and Maigat, 2007).

  • 16726.
    Ulvesand, Andreas
    et al.
    KTH, School of Computer Science and Communication (CSC).
    Eriksson, Daniel
    KTH, School of Computer Science and Communication (CSC).
    Native Code on Android – A performance comparison of Java and native C on Android.2011Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report evaluates possible performance differences between Java and native C on the operating system Android, by developing tests and analyzing the execution. The ambition is that each test should evaluate the performance of a certain task, such as memory access or arithmetic operations of different data types. The results were in some cases unexpected and show that the executed implementations were faster on C compared to Java on one of the test devices, but not the other. The conclusion partly opposes earlier research and this is probably partly due to the fact that the Java Virtual Machine has been improved vastly in the latest versions of Android.

  • 16727.
    Ulvö, Fredrik
    University of Skövde, School of Humanities and Informatics.
    Systemlösningsmigrationer till öppen källkod: En analys av utförda migrationsprojekt i offentliga förvaltningar sett utifrån ett riskperspektiv2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den här studien bidrar till attöka kunskapen inom området systemlösningsmigrationer genomatt ta reda på vad som går att lära av tidigare genomförda migrationsprojekt. Studien genomförs genom att utföra fallstudier på avrapporterade migrationsprojekt som har utfört en migration från att använda proprietära systemlösningar till att använda systemlösningar baserade på öppen källkod. Efter en urvalsprocess kvarstod tre migrationsprojekt aktuella för analys utifrån ett riskperspektiv. Det var migrationsprojektet LiMux i Tyskland,ett projekt inom det franska gendarmeriet och ett projekt som utfördes bland skolorna i Bolzanoprovinsen i Italien.

    Resultatet av studien visar bland annat att alla tre migrationsprojekten upplevde risken att inte kunna ta egna IT-beslut före den utförda migrationen. Detta berodde på att de före migrationen använde sig av proprietära systemlösningar, vilka de upplevt varit orsaken till detta. Den här risken säger de sig nu ha kunnat undvika genom att använda systemlösningar baserade på öppen källkod. De risker som förvaltningarna upplevt efter utförd migration kan sammanfattas med att det är risker som medför kortsiktiga problem för förvaltningarna. De räknar med att riskerna kommer att minska och problem kommer att lösas allt eftersom tiden går. Till exempel upplevde de att de har varit tvungna att anlita extern support för att lösa tekniska frågor relaterade till den nya systemlösningen. De säger dock att de i framtiden räknar med att själva ansvara för supporten när personalens kompetens har höjts inom förvaltningarna.

    Studien visar också att en modell, BRW Migration Model for desktop OSS, kan användas för att minska riskerna vid en migrationsprocess. Detta görs genom att följa de nio steg som modellen beskriver som viktiga för en lyckad migrationsprocess.

  • 16728. Umbert, M.
    et al.
    Bonada, J.
    Goto, M.
    Nakano, T.
    Sundberg, Johan
    Uppsala University, Sweden.
    Expression control in singing voice synthesis: Features, approaches, evaluation, and challenges2015In: IEEE signal processing magazine (Print), ISSN 1053-5888, E-ISSN 1558-0792, Vol. 32, no 6, p. 55-73Article in journal (Refereed)
    Abstract [en]

    In the context of singing voice synthesis, expression control manipulates a set of voice features related to a particular emotion, style, or singer. Also known as performance modeling, it has been approached from different perspectives and for different purposes, and different projects have shown a wide extent of applicability. The aim of this article is to provide an overview of approaches to expression control in singing voice synthesis. We introduce some musical applications that use singing voice synthesis techniques to justify the need for an accurate control of expression. Then, expression is defined and related to speech and instrument performance modeling. Next, we present the commonly studied set of voice parameters that can change perceptual aspects of synthesized voices. After that, we provide an up-to-date classification, comparison, and description of a selection of approaches to expression control. Then, we describe how these approaches are currently evaluated and discuss the benefits of building a common evaluation framework and adopting perceptually-motivated objective measures. Finally, we discuss the challenges that we currently foresee.

  • 16729.
    Umefjord, Göran
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Hamberg, Katarina
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Malker, Hans
    Mid-Sweden Research and Development Centre, County Council of Va¨ sternorrland, Sundsvall, Sweden.
    Petersson, Göran
    Health Institute, Department of Health and Behavioural Science, University of Kalmar, Sweden.
    The use of an internet-based ask the doctor service involving family physicians: evaluation by a web survey2006In: Family Practice, ISSN 0263-2136, E-ISSN 1460-2229, Vol. 23, no 2, p. 159-166Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Internet consultation without a previous relationship between the doctor and the enquirer seems to be increasing in popularity. However, little is known about the advantages, disadvantages or other differences compared with regular health care when using this kind of service. OBJECTIVE: To investigate how an Internet-based Ask the Doctor service out with any pre-existing doctor-patient relationship was used and evaluated by the enquirers. METHODS: We recruited to a web-based survey users of the non-commercial Swedish Internet-based Ask the Doctor service run by family physicians. The survey was conducted between November 2001 and January 2002. Questions included both multiple choice and free text formats, and the results were analysed quantitatively and qualitatively. RESULTS: The survey was completed by 1223 participants. It was mainly women who submitted questions to the service (29% men, 71% women) and also who participated in the survey (26% men, 74% women). Most participants (77%) wrote their question at home, and 80% asked on their own behalf. Almost half of the enquiries (45%) concerned a medical matter that had not been evaluated by a medical professional before. After reading the answer, 43% of the participants indicated that they would not pursue their question further having received sufficient information in the answer provided. The service was appreciated for its convenience and flexibility, but also for reasons to do with the mode of communication such as the ability to reflect on the written answer without having to hurry and to read it more than once. CONCLUSION: In the present study, we found that an Internet-based Ask the Doctor service run by family physicians on the whole was evaluated positively by the participants both in terms of the answers and the service. Internet-based consultation may act as a complement to regular health care. In future studies, the cost-effectiveness, patient security, responsibilities of the Internet doctor and the role of Ask the Doctor services compared with regular health care should be evaluated.

  • 16730.
    Umefjord, Göran
    et al.
    Nyland Health Center, Biskopsgatan 1, SE-870 52 Nyland, Sweden.
    Petersson, Göran
    Department of Otorhinolaryngology, Lund University, Sweden.
    Hamberg, Katarina
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Reasons for consulting a doctor on the Internet: Web survey of users of an Ask the Doctor service2003In: Journal of Medical Internet Research, ISSN 1438-8871, E-ISSN 1438-8871, Vol. 5, no 4, p. e26-Article in journal (Other academic)
    Abstract [en]

    BACKGROUND: In 1998 the Swedish noncommercial public health service Infomedica opened an Ask the Doctor service on its Internet portal. At no charge, anyone with Internet access can use this service to ask questions about personal health-related and disease-related matters. OBJECTIVE: To study why individuals choose to consult previously-unknown doctors on the Internet. METHODS: Between November 1, 2001, and January 31, 2002 a Web survey of the 3622 Ask the Doctor service users, 1036 men (29%) and 2586 (71%) women, was conducted. We excluded 186 queries from users. The results are based on quantitative and qualitative analysis of the answers to the question "Why did you choose to ask a question at Infomedica's 'Ask the Doctor' service?" RESULTS: 1223 surveys were completed (response rate 36 %). Of the participants in the survey 322 (26%) were male and 901 (74%) female. As major reasons for choosing to consult previously-unknown doctors on the Internet participants indicated: convenience (52%), anonymity (36%), "doctors too busy" (21%), difficult to find time to visit a doctor (16%), difficulty to get an appointment (13%), feeling uncomfortable when seeing a doctor (9%), and not being able to afford a doctors' visit (3%). Further motives elicited through a qualitative analysis of free-text answers were: seeking a second opinion, discontent with previous doctors and a wish for a primary evaluation of a medical problem, asking embarrassing or sensitive questions, seeking information on behalf of relatives, preferring written communication, and (from responses by expatriates, travelers, and others) living far away from regular health care. CONCLUSIONS: We found that that an Internet based Ask the Doctor service is primarily consulted because it is convenient, but it may also be of value for individuals with needs that regular health care services have not been able to meet.

  • 16731. Unat, Didem
    et al.
    Dubey, Anshu
    Hoefler, Torsten
    Shalf, John
    Abraham, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical & Computational Biophysics.
    Bianco, Mauro
    Chamberlain, Bradford L.
    Cledat, Romain
    Edwards, H. Carter
    Finkel, Hal
    Fuerlinger, Karl
    Hannig, Frank
    Jeannot, Emmanuel
    Kamil, Amir
    Keasler, Jeff
    Kelly, Paul H. J.
    Leung, Vitus
    Ltaief, Hatem
    Maruyama, Naoya
    Newburn, Chris J.
    Pericas, Miquel
    Trends in Data Locality Abstractions for HPC Systems2017In: IEEE Transactions on Parallel and Distributed Systems, ISSN 1045-9219, E-ISSN 1558-2183, Vol. 28, no 10, p. 3007-3020Article in journal (Refereed)
    Abstract [en]

    The cost of data movement has always been an important concern in high performance computing (HPC) systems. It has now become the dominant factor in terms of both energy consumption and performance. Support for expression of data locality has been explored in the past, but those efforts have had only modest success in being adopted in HPC applications for various reasons. them However, with the increasing complexity of the memory hierarchy and higher parallelism in emerging HPC systems, locality management has acquired a new urgency. Developers can no longer limit themselves to low-level solutions and ignore the potential for productivity and performance portability obtained by using locality abstractions. Fortunately, the trend emerging in recent literature on the topic alleviates many of the concerns that got in the way of their adoption by application developers. Data locality abstractions are available in the forms of libraries, data structures, languages and runtime systems; a common theme is increasing productivity without sacrificing performance. This paper examines these trends and identifies commonalities that can combine various locality concepts to develop a comprehensive approach to expressing and managing data locality on future large-scale high-performance computing systems.

  • 16732.
    Unnikrishnan, Vishnu
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Design of VCO-based ADCs2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today's complex electronic systems with billions of transistors on a single die are enabled by the aggressive scaling down of the device feature size at an exponential rate as predicted by the Moore's law. Digital circuits benefit from technology scaling to become faster, more energy efficient as well as more area efficient as the feature size is scaled down. Moreover, digital design also benefits from mature CAD tools that simplify the design and cross-technology porting of complex systems, leveraging on a cell-based design methodology. On the other hand, the design of analog circuits is getting increasingly difficult as the feature size scales down into the deep nanometer regime due to a variety of reasons like shrinking voltage headroom, reducing intrinsic gain of the devices, increasing noise coupling between circuit nodes due to shorter distances etc. Furthermore, analog circuits are still largely designed with a full custom design ow that makes their design and porting tedious, slow, and expensive. In this context, it is attractive to consider realizing analog/mixed-signal circuits using standard digital components. This leads to scaling-friendly mixed-signal blocks that can be designed and ported using the existing CAD framework available for digital design. The concept is already being applied to mixed-signal components like frequency synthesizers where all-digital architectures are synthesized using standard cells as basic components. This can be extended to other mixed-signal blocks like digital-to-analog and analog to- digital converters as well, where the latter is of particular interest in this thesis.

    A voltage-controlled oscillator (VCO)-based analog-to-digital converter (ADC) is an attractive architecture to achieve all-digital analog-to digital conversion due to favorable properties like shaping of the quantization error, inherent anti-alias filtering etc. Here a VCO operates as a signal integrator as well as a quantizer. A converter employing a ring oscillator as the VCO lends itself to an all-digital implementation.

    In this dissertation, we explore the design of VCO-based ADCs synthesized using digital standard cells with the long-term goal of achieving high performance data converters built from low accuracy switch components. In a first step, an ADC is designed using vendor supplied standard cells and fabricated in a 65 nm CMOS process. The converter delivers an 8-bit ENOB over a 25 MHz bandwidth while consuming 3.3 mW of power resulting in an energy efficiency of 235 fJ/step (Walden FoM). Then we utilize standard digital CAD tools to synthesize converter designs that are fully described using a hardware description language. A polynomial-based digital post-processing scheme is proposed to correct for the VCO nonlinearity. In addition, pulse modulation schemes like delta modulation and asynchronous sigma-delta modulation are used as a signal pre-coding scheme, in an attempt to reduce the impact of VCO nonlinearity on converter performance. In order to investigate the scaling benefits of all-digital data conversion, a VCO-based converter is designed in a 28 nm CMOS process. The design delivers a 13.4-bit ENOB over a 5 MHz bandwidth achieving an energy efficiency of 4.3 fJ/step according to post-synthesis schematic simulation, indicating that such converters have the potential of achieving good performance in deeply scaled processes by exploiting scaling benefits. Furthermore, large conversion errors caused by non-ideal sampling of the oscillator phase are studied. An encoding scheme employing ones counters is proposed to code the sampled ring oscillator output into a number, which is resilient to a class of sampling induced errors modeled by temporal reordering of the transitions in the ring. The proposed encoding reduces the largest error caused by random reordering of up to six subsequent bits in the sampled signal from 31 to 2 LSBs. Finally, the impact of process, voltage, and temperature (PVT) variations on the performance while operating the converter from a subthreshold supply is investigated. PVT-adaptive solutions are suggested as a means to achieve energy-efficient operation over a wide range of PVT conditions.

  • 16733.
    Uppgard, Tomas
    et al.
    KTH.
    Jonsson, A.
    KTH.
    Appelgren, Ester
    KTH.
    The Swedish newspaper industry's changing business strategies for multi-channel publishing 1995-20042004In: EADOPTION AND THE KNOWLEDGE ECONOMY: ISSUES, APPLICATIONS, CASE STUDIES, PTS 1 AND 2, AMSTERDAM: I O S PRESS , 2004, Vol. 1, p. 499-506Conference paper (Refereed)
    Abstract [en]

    The Swedish newspaper industry has gone through five major phases of multi channel business strategy from 1995 - 2004. The strategies have changed from "experimental learning" to "demands for profitability". Today's challenge is to understand the complex relationships between the different channels. Synergies can be achieved both for content delivery and advertising. During the spring of 2004, Swedish media have reported about several developments where the online advertising players gain ground at the expense of advertising in printed media. As a consequence of this development, major media companies in Sweden take considerable action to compete in this newborn online market. Other important challenges to handle over the years to come are; development of premium pay services, online classified advertising partnerships, display advertising packages in several channels and creation of an organization designed to promote change.

  • 16734.
    Uppman, Hannes
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Computational Complexity of the Minimum Cost Homomorphism Problem on Three-element Domains2014Conference paper (Refereed)
    Abstract [en]

    In this paper we study the computational complexity of the extended minimum cost homomorphism problem (Min-Cost-Hom) as a function of a constraint language, i.e. a set of constraint relations and cost functions that are allowed to appear in instances. A wide range of natural combinatorial optimisation problems can be expressed as extended Min-Cost-Homs and a classification of their complexity would be highly desirable, both from a direct, applied point of view as well as from a theoretical perspective.

    The extended Min-Cost-Hom can be understood either as a flexible optimisation version of the constraint satisfaction problem (CSP) or a restriction of the (general-valued) valued constraint satisfaction problem (VCSP). Other optimisation versions of CSPs such as the minimum solution problem (Min-Sol) and the minimum ones problem (Min-Ones) are special cases of the extended Min-Cost-Hom.

    The study of VCSPs has recently seen remarkable progress. A complete classification for the complexity of finite-valued languages on arbitrary finite domains has been obtained Thapper and Živný [STOC’13]. However, understanding the complexity of languages that are not finitevalued appears to be more difficult. The extended Min-Cost-Hom allows us to study problematic languages of this type without having to deal with with the full generality of the VCSP. A recent classification for the complexity of three-element Min-Sol, Uppman [ICALP’13], takes a step in this direction. In this paper we generalise this result considerably by determining the complexity of three-element extended Min-Cost-Hom.

  • 16735.
    Uppman, Hannes
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Max-Sur-CSP on Two Elements2012In: Principles and Practice of Constraint Programming: 18th International Conference, CP 2012, Québec City, QC, Canada, October 8-12, 2012. Proceedings / [ed] Michela Milano, Springer Berlin Heidelberg , 2012, p. 38-54Conference paper (Refereed)
    Abstract [en]

    Max-Sur-CSP is the following optimisation problem: given a set of constraints, find a surjective mapping of the variables to domain values that satisfies as many of the constraints as possible. Many natural problems, e.g. Minimum k-Cut (which has many different applications in a variety of fields) and Minimum Distance (which is an important problem in coding theory), can be expressed as Max-Sur-CSPs. We study Max-Sur-CSP on the two-element domain and determine the computational complexity for all constraint languages (families of allowed constraints). Our results show that the problem is solvable in polynomial time if the constraint language belongs to one of three classes, and NP-hard otherwise. An important part of our proof is a polynomial-time algorithm for enumerating all near-optimal solutions to a generalised minimum cut problem. This algorithm may be of independent interest.

  • 16736.
    Uppman, Hannes
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    On Some Combinatorial Optimization Problems: Algorithms and Complexity2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is about the computational complexity of several classes of combinatorial optimization problems, all related to the constraint satisfaction problems.

    A constraint language consists of a domain and a set of relations on the domain. For each such language there is a constraint satisfaction problem (CSP). In this problem we are given a set of variables and a collection of constraints, each of which is constraining some variables with a relation in the language. The goal is to determine if domain values can be assigned to the variables in a way that satisfies all constraints. An important question is for which constraint languages the corresponding CSP can be solved in polynomial time. We study this kind of question for optimization problems related to the CSPs.

    The main focus is on extended minimum cost homomorphism problems. These are optimization versions of CSPs where instances come with an objective function given by a weighted sum of unary cost functions, and where the goal is not only to determine if a solution exists, but to find one of minimum cost. We prove a complete classification of the complexity for these problems on three-element domains. We also obtain a classification for the so-called conservative case.

    Another class of combinatorial optimization problems are the surjective maximum CSPs. These problems are variants of CSPs where a non-negative weight is attached to each constraint, and the objective is to find a surjective mapping of the variables to values that maximizes the weighted sum of satisfied constraints. The surjectivity requirement causes these problems to behave quite different from for example the minimum cost homomorphism problems, and many powerful techniques are not applicable. We prove a dichotomy for the complexity of the problems in this class on two-element domains. An essential ingredient in the proof is an algorithm that solves a generalized version of the minimum cut problem. This algorithm might be of independent interest.

    In a final part we study properties of NP-hard optimization problems. This is done with the aid of restricted forms of polynomial-time reductions that for example preserves solvability in sub-exponential time. Two classes of optimization problems similar to those discussed above are considered, and for both we obtain what may be called an easiest NP-hard problem. We also establish some connections to the exponential time hypothesis.

  • 16737.
    Uppman, Hannes
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    The Complexity of Three-Element Min-Sol and Conservative Min-Cost-Hom2013In: Automata, Languages, and Programming: 40th International Colloquium, ICALP 2013, Riga, Latvia, July 8-12, 2013, Proceedings, Part I / [ed] Fedor V. Fomin, Rūsiņš Freivalds, Marta Kwiatkowska, David Peleg, Springer Berlin/Heidelberg, 2013, p. 804-815Conference paper (Refereed)
    Abstract [en]

    Thapper and Živný [STOC’13] recently classified the complexity of VCSP for all finite-valued constraint languages. However, the complexity of VCSPs for constraint languages that are not finite-valued remains poorly understood. In this paper we study the complexity of two such VCSPs, namely Min-Cost-Hom and Min-Sol. We obtain a full classification for the complexity of Min-Sol on domains that contain at most three elements and for the complexity of conservative Min-Cost-Hom on arbitrary finite domains. Our results answer a question raised by Takhanov [STACS’10, COCOON’10].

  • 16738.
    Uppsäll, Caroline
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, Department of Computer Science and Engineering.
    How to Incorporate Security Requirements into the ArchWiz Tool2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis have two tasks: one is to help in the development of the ArchWiztool at ABB and the other is to find a way of how to formalise security related architecturalresponsibilities in a general way so that they can be incorporated in the tool. This thesis report focuses on thesoftware quality attribute security.The ArchWiz tool is developed at ABB Corporate Research in Västerås. The scopeof the tool is to serve as a software architecture guidance and knowledge tool for all softwarearchitecture professionals within ABB. The ArchWiz tool is a way of helping the architects of ABB to matchtheir product requirements with a list of general reusable requirements. The matched productrequirements can then use the reusable requirement's architectural solutions, which are also presentedin the tool. The tool focuses on usability, security and safety in this first version but it isconstructed so that the user can add their own general requirements regarding any quality.The architecture design phase in the development of a software system is a keypart in the development process, it gives the first design decisions and gives informationon if the system will have potential to meet its key requirements. Security is a software quality thathas grown in importance for the architectural design of the system. There exist a number of potentialthreats and attacks that might breach the security of the software and these threats needs to beprotected against. The ArchWiz project closed in December 2009 and at that time the tool was notfinished. A good foundation and a GUI framework for further implementations were developed but toget a fully functioning tool more implementations need to be made. Security is one of thequality attributes, which the ArchWiz is supposed to support. Suggestions on how to formalise securityresponsibilities in the tool have in this thesis been created and analysed. However, the suggestionsneed to be in incorporated in the tool and tested through users tests with the ABB architects.With the user tests as basis, the best suggestion can be selected.

  • 16739.
    ur Rehman, Shafiq
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    iFeeling: vibrotactile rendering of human emotions on mobile phones2010In: Mobile multimedia processing: fundamentals, methods, and applications, Springer, 2010, p. 1-20Conference paper (Refereed)
    Abstract [en]

    Today, the mobile phone technology is mature enough to enable us to effectively interact with mobile phones using our three major senses namely, vision, hearing and touch. Similar to the camera, which adds interest and utility to mobile experience, the vibration motor in a mobile phone could give us a new possibility to improve interactivity and usability of mobile phones. In this chapter, we show that by carefully controlling vibration patterns, more than 1-bit information can be rendered with a vibration motor. We demonstrate how to turn a mobile phone into a social interface for the blind so that they can sense emotional information of others. The technical details are given on how to extract emotional information, design vibrotactile coding schemes, render vibrotactile patterns, as well as how to carry out user tests to evaluate its usability. Experimental studies and users tests have shown that we do get and interpret more than one bit emotional information. This shows a potential to enrich mobile phones communication among the users through the touch channel.

  • 16740.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Expressing emotions through vibration for perception and control2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis addresses a challenging problem: “how to let the visually impaired ‘see’ others emotions”. We, human beings, are heavily dependent on facial expressions to express ourselves. A smile shows that the person you are talking to is pleased, amused, relieved etc. People use emotional information from facial expressions to switch between conversation topics and to determine attitudes of individuals. Missing emotional information from facial expressions and head gestures makes the visually impaired extremely difficult to interact with others in social events. To enhance the visually impaired’s social interactive ability, in this thesis we have been working on the scientific topic of ‘expressing human emotions through vibrotactile patterns’.

    It is quite challenging to deliver human emotions through touch since our touch channel is very limited. We first investigated how to render emotions through a vibrator. We developed a real time “lipless” tracking system to extract dynamic emotions from the mouth and employed mobile phones as a platform for the visually impaired to perceive primary emotion types. Later on, we extended the system to render more general dynamic media signals: for example, render live football games through vibration in the mobile for improving mobile user communication and entertainment experience. To display more natural emotions (i.e. emotion type plus emotion intensity), we developed the technology to enable the visually impaired to directly interpret human emotions. This was achieved by use of machine vision techniques and vibrotactile display. The display is comprised of a ‘vibration actuators matrix’ mounted on the back of a chair and the actuators are sequentially activated to provide dynamic emotional information. The research focus has been on finding a global, analytical, and semantic representation for facial expressions to replace state of the art facial action coding systems (FACS) approach. We proposed to use the manifold of facial expressions to characterize dynamic emotions. The basic emotional expressions with increasing intensity become curves on the manifold extended from the center. The blends of emotions lie between those curves, which could be defined analytically by the positions of the main curves. The manifold is the “Braille Code” of emotions.

    The developed methodology and technology has been extended for building assistive wheelchair systems to aid a specific group of disabled people, cerebral palsy or stroke patients (i.e. lacking fine motor control skills), who don’t have ability to access and control the wheelchair with conventional means, such as joystick or chin stick. The solution is to extract the manifold of the head or the tongue gestures for controlling the wheelchair. The manifold is rendered by a 2D vibration array to provide user of the wheelchair with action information from gestures and system status information, which is very important in enhancing usability of such an assistive system. Current research work not only provides a foundation stone for vibrotactile rendering system based on object localization but also a concrete step to a new dimension of human-machine interaction.

  • 16741.
    Urdén, Ulf
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    A Comparison of Three Computer System Simulators2004Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    This thesis is a comparative study of three computer system simulators. These computer programs are commonly used to test the efficiency and feasibility of new computer architectures, as well for debugging and testing software. With this study, we evaluate the fundamental differences of three simulators: SimICS, SimpleScalar and ML-RSIM. A comprehensive study of simulation techniques is presented, and each evaluated simulator is classified using those premises. Quantification the performance differences using a benchmark suite is made. The results show that the most feature-rich of the simulators also seems to have the highest performance in the group.

  • 16742.
    Urhed, Casper
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Mossberg, Robert
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Grafit: Webbapplikation för datapresentation2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Graphical presentation of data stored in databases is commonly achieved with desktop software which requires the data to be transferred from the database to the local machine and then processed with software. This method requires knowledge in database-related languages and tools such as SQL, and is thus demanding or inaccessible to users without a certain level of education or experience in these languages and tools. The goal of this study is to create an application that eliminates the need for advanced competence in such languages and tools to make it possible for a broader subset of users to graphically present data stored in databases. To achieve this goal, a web application has been developed that features a simple GUI for connecting to a remote database and creating charts from the data stored there. The application generates queries to the databases according to the user’s input in the GUI. For security and convenience the application has been developed with a role-based access control system.

  • 16743.
    Urkia Kortabarria, Mikel
    University of Skövde, School of Humanities and Informatics. Mondragon Unibertsitatea.
    Web Service Performance on Heterogeneous Systems: A performance comparison between J2EE and .NET on heterogeneous systems2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At the moment, two main web platforms have the monopoly of web service business; NET and J2EE have been competitors in this area for many years. Within last years, a technological advance has occurred with the appearance of Mono, an open source project that allows NET technologies to be taken into operating systems other than Microsoft Windows. This opens an information gap that needs to be solved with a new and actualised performance analysis.

    This thesis work identifies the performance characteristics of the web platforms on heterogeneous systems. The aim of this study is to investigate different performance characteristics of .NET and J2EE web services in heterogeneous systems. The student systems are Windows 7 and Ubuntu Linux.

    A set of web services is built following different service structures, which are then exposed to some quantitative and qualitative test following predefined criteria. The results demonstrate that both .NET and J2EE are suitable web platforms under different circumstances, based mostly on the communication protocol and operating system. This work identifies the best combination of web platform and operating system for each of the web service structures, which can vary for each company.

  • 16744.
    Urmi, Jaak
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    A machine independent LISP compiler and its implications for ideal hardware1978Doctoral thesis, monograph (Other academic)
    Abstract [en]

    A LISP compiler is constructed without any a priori assumptions about the target machine. In parallel with the compiler a LISP oriented instruction set is developed. The instruction set can be seen as either an intermediarylanguage for a traditional computer oras the instruction set for a special purpose LISP machine. The code produced by the compiler is evaluated with regard to its static and dynamic properties. Finally some architectural aspects on LISP oriented hardware are discussed. The notion of segments with different word lengths, under program control, is developed and a proposed implementation of this is described.    

  • 16745.
    Ur-Rehman, Shoaib
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ullah, Irshan
    Blekinge Institute of Technology, School of Computing.
    Analysis of Black Hole attack on MANETs Using different MANET routing protocol2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    ABSTRACT Wireless networks are gaining popularity day by day, as users want wireless connectivity irrespective of their geographic position. There is an increasing threat of malicious nodes attacks on the Mobile Ad-hoc Networks (MANET). Black hole attack is one of the security threat in which the traffic is redirected to such a node that actually does not exist in the network. It’s an analogy to the black hole in the universe in which things disappear. MANETs must have a secure way for transmission and communication which is quite challenging and vital issue. In order to provide secure communication and transmission, researcher worked specifically on the security issues in MANETs, and many secure routing protocols and security measures within the networks were proposed. The scope of this thesis is to study the effects of Black hole attack in MANET using both Proactive routing protocol i.e. Optimized Link State Routing (OLSR) and Reactive routing protocol Ad-Hoc on Demand Distance Vector (AODV). Comparative analysis of Black Hole attack for both protocols is taken into account. The impact of Black Hole attack on the performance of MANET is evaluated finding out which protocol is more vulnerable to the attack and how much is the impact of the attack on both protocols. The measurements were taken in the light of throughput, end-to-end delay and network load. Simulation is done in Optimized Network Engineering Tool (OPNET). Previously the works done on security issues in MANET were based on reactive routing protocol like Ad-Hoc on Demand Distance Vector (AODV). Different kinds of attacks were studied, and their effects were elaborated by stating how these attacks disrupt the performance of MANET.

  • 16746.
    Uttermalm, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Audio streaming on top of 802.11n in an IoT context: An implementation along with a literature study of wireless IoT standards2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things (IoT) is a concept that revolves around ordinary devices that are connected to the internet for extended control and ease of use. Altran, a company dealing in high technology and innovation consultancy, predicts a large growth in business opportunities in the IoT area in the coming years, and therefore wants to invest in knowledge about the Internet of Things. Altran wanted a report that described popular wireless IoT communication technologies along with a proposal for a general IoT communication platform or base that could be used to implement many of these technologies. Additionally, an audio streaming application were to be implemented on the proposed platform to validate its credibility. The project resulted in a report on 6 different wireless IoT technologies: Z-wave, ZigBee, Thread, Bluetooth, 802.11n, and 802.11ah. A hardware and software base was proposed that could implement 4 of 6 of these technologies. This base was the Raspberry Pi 2 along with the Raspbian Jessie operating system. Finally an audio streaming system that could stream data to a set of smart Speaker nodes over wireless links based on IEEE 802.11n was implemented on the proposed base.

  • 16747.
    Uusitalo, Tim
    Blekinge Institute of Technology, School of Computing.
    A first approach in applying Artificial Potential Fields in Car Games2011Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    In car racing simulation games, finishing first is the main goal. To reach that goal, it is required to go around a racing track, competing against other cars aiming for the same goal. Implementing a bot for doing so may have its difficulties, although using a technique called multi-agent systems combined with artificial potential field, let- ting the agents take care of subtasks like keeping the car on the track, minimize how much the car turns in a curvature and basics in navigation around the track, has showed that artificial potential fields very well fit the problem of driving a car in simulated car racing in a competitive way.

  • 16748.
    Uvman, Oliver
    Linköping University, Department of Computer and Information Science, Human-Centered systems.
    Evaluating the Leap Motion Device for Music Visualization2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    An experiment was carried out, attempting to ascertain whether the Leap Motion Controller can be a useful input device for dynamically controlling graphic visualizations, e.g. by artists who use video and interactive visual arts to enhance music performances. The Leap Motion Controller was found to be too unreliable to be used as the primary controller in a professional visual arts performance.

  • 16749.
    Vaara, Elsa
    et al.
    Mobile Life, Swedish Institute of Computer Science.
    Höök, Kristina
    Stockholm University .
    Tholander, Jakob
    Stockholm University .
    Mirroring Bodily Reactions Over Time2009In: Extended Abstracts on Human Factors in Computing System., ACM Digital Library, 2009, p. 4471-4476Conference paper (Refereed)
    Abstract [en]

    The Affective Health system is a mobile lifestyle application that aims to empower people to reflect on their lives and lifestyles. The system logs a mixture of biosensor-data and other contextually oriented data and transforms these to a colorful, animated expression on their mobiles. It is intended to create a mirror and thereby empower users to see activity patterns and relate these to their experiences of stress. People’s different cultural backgrounds and their different physiological and psychological composition give them different perceptions and associations of time. We explore the time dimension of our system through working through a set of different designs that organize events as time going linearly forward, in a circular movement or relating to geographical places. Here we discuss the process of designing a mobile interface for presenting temporal data in a way that allows multiple and subjective interpretation. 

  • 16750.
    Vadi-Dris, David
    et al.
    Örebro University, School of Science and Technology.
    Pasma, Miika
    Örebro University, School of Science and Technology.
    Game Entry to Swedish Game Awards: "Winds of Kahlara"2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a report that describes the implementation of a computer technical examination project at Örebro University. More specifically it is about how two students have developed a computer game as an entry for Swedish Game Awards, a competition for games developed without interaction from commercial companies. The game, titled “Winds of Kahlara”, is written for PC and lets the participants compete against each other over a network in a 3D environment. The graphical theme is fantasy and the players utilize among other things magical attacks to kill their opponents. The development itself has taken more than a year since the complexity of the game has required extensive technical research and graphical designing.

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