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  • 201.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ben Henda, Noomene
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Mayr, Richard
    Decisive Markov Chains2007In: Logical Methods in Computer Science, ISSN 1860-5974, E-ISSN 1860-5974, Vol. 3, no 4, p. 1-32Article in journal (Refereed)
    Abstract [en]

    We consider qualitative and quantitative verification problems for infinite-state Markov chains. We call a Markov chain decisive w.r.t. a given set of target states F if it almost certainly eventually reaches either F or a state from which F can no longer be reached. While all finite Markov chains are trivially decisive (for every set F), this also holds for many classes of infinite Markov chains. Infinite Markov chains which contain a finite attractor are decisive w.r.t. every set F. In particular, this holds for probabilistic lossy channel systems (PLCS). Furthermore, all globally coarse Markov chains are decisive. This class includes probabilistic vector addition systems (PVASS) and probabilistic noisy Turing machines (PNTM). We consider both safety and liveness problems for decisive Markov chains, i.e., the probabilities that a given set of states F is eventually reached or reached infinitely often, respectively. 1. We express the qualitative problems in abstract terms for decisive Markov chains, and show an almost complete picture of its decidability for PLCS, PVASS and PNTM. 2. We also show that the path enumeration algorithm of Iyer and Narasimha terminates for decisive Markov chains and can thus be used to solve the approximate quantitative safety problem. A modified variant of this algorithm solves the approximate quantitative liveness problem. 3. Finally, we show that the exact probability of (repeatedly) reaching F cannot be effectively expressed (in a uniform way) in Tarski-algebra for either PLCS, PVASS or (P)NTM.

  • 202.
    Abdulla, Parosh
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DoCS.
    Ben Henda, Noomene
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DoCS.
    Mayr, Richard
    Sandberg, Sven
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datalogi.
    Eager Markov Chains: Eager Markov Chains2006In: Proceedings of the fourth international symposium on Automated Technology for Verification and Analysis (ATVA), 2006, p. 24-38Conference paper (Refereed)
    Abstract [en]

    We consider infinite-state discrete Markov chains which are eager:

    the probability of avoiding a defined set of final states for more than n steps is bounded by some exponentially decreasing function f(n).

    We prove that eager Markov chains include those induced by Probabilistic Lossy Channel Systems, Probabilistic Vector Addition Systems with States, and Noisy Turing Machines, and that the bounding function f(n) can be effectively constructed for them.

    Furthermore, we study the problem of computing the expected reward (or cost) of runs until reaching the final states, where rewards are assigned to individual runs by computable reward functions.

    For eager Markov chains, an effective path exploration scheme,

    based on forward reachability analysis, can be used to approximate the expected reward up-to an arbitrarily small error.

  • 203.
    Abdulla, Parosh
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DoCS.
    Ben Henda, Noomene
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DoCS.
    Mayr, Richard
    Sandberg, Sven
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datalogi.
    Limiting Behavior of Markov Chains with Eager Attractors2006In: Third International Conference on the Quantitative Evaluation of Systems (QEST), 2006, p. 253-262Conference paper (Refereed)
  • 204.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ciobanu, Radu
    Univ Edinburgh, Edinburgh, Midlothian, Scotland..
    Mayr, Richard
    Univ Edinburgh, Edinburgh, Midlothian, Scotland..
    Sangnier, Arnaud
    Univ Paris Diderot, CNRS, LIAFA, Sorbonne Paris Cite, Paris, France..
    Sproston, Jeremy
    Univ Turin, Turin, Italy..
    Qualitative Analysis of VASS-Induced MDPs2016In: Foundations Of Software Science And Computation Structures (FOSSACS 2016) / [ed] Jacobs, B Loding, C, 2016, p. 319-334Conference paper (Refereed)
    Abstract [en]

    We consider infinite-state Markov decision processes (MDPs) that are induced by extensions of vector addition systems with states (VASS). Verification conditions for these MDPs are described by reachability and Buchi objectives w.r.t. given sets of control-states. We study the decidability of some qualitative versions of these objectives, i.e., the decidability of whether such objectives can be achieved surely, almostsurely, or limit-surely. While most such problems are undecidable in general, some are decidable for large subclasses in which either only the controller or only the random environment can change the counter values (while the other side can only change control-states).

  • 205.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Delzanno, Giorgio
    Rezine, Ahmed
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Parameterized Verification of Infinite-state Processes with Global Conditions2007In: Computer Aided Verification, Proceedings / [ed] Damm W, Hermanns H, 2007, p. 145-157Conference paper (Refereed)
    Abstract [en]

    We present a simple and effective approximated backward reachability algorithm for parameterized systems with existentially and universally quantified global conditions. The individual processes operate on unbounded local variables ranging over the natural numbers. In addition, processes may communicate via broadcast, rendez-vous and shared variables. We apply the algorithm to verify mutual exclusion for complex protocols such as Lamport's bakery algorithm both with and without atomicity conditions, a distributed version of the bakery algorithm, and Ricart-Agrawala's distributed mutual exclusion algorithm.

  • 206.
    Abdulla, Parosh
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Deneux, Johann
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Mahata, Pritha
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Multi-Clock Timed Networks2004In: LICS'2004, 18th IEEE Int. Symp. on Logic in Computer Science, 2004Conference paper (Refereed)
  • 207.
    Abdulla, Parosh
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Deneux, Johann
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Mahata, Pritha
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Open, Closed and Robust Timed Networks.2004In: CONCUR 2004 -- Concurrency Theory: 15th International Conference, London, UK, August 31 - September 3, 2004, Proceedings, 2004, p. 529-Conference paper (Refereed)
  • 208.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Haziza, Frédéric
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Holík, Lukás
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Brno Univ Technol, Brno, Czech Republic..
    Jonsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rezine, Ahmed
    Linköping Univ, Linköping, Sweden..
    An integrated specification and verification technique for highly concurrent data structures for highly concurrent data structures2017In: International Journal on Software Tools for Technology Transfer (STTT), ISSN 1433-2779, E-ISSN 1433-2787, Vol. 19, no 5, p. 549-563Article in journal (Refereed)
    Abstract [en]

    We present a technique for automatically verifying safety properties of concurrent programs, in particular programs that rely on subtle dependencies of local states of different threads, such as lock-free implementations of stacks and queues in an environment without garbage collection. Our technique addresses the joint challenges of infinite-state specifications, an unbounded number of threads, and an unbounded heap managed by explicit memory allocation. Our technique builds on the automata-theoretic approach to model checking, in which a specification is given by an automaton that observes the execution of a program and accepts executions that violate the intended specification. We extend this approach by allowing specifications to be given by a class of infinite-state automata. We show how such automata can be used to specify queues, stacks, and other data structures, by extending a data-independence argument. For verification, we develop a shape analysis, which tracks correlations between pairs of threads, and a novel abstraction to make the analysis practical. We have implemented our method and used it to verify programs, some of which have not been verified by any other automatic method before.

  • 209.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Iyer, Purushothaman
    Nylén, Aletta
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    SAT-solving the Coverability Problem for Unbounded Petri Nets2004In: Formal methods in system design, ISSN 0925-9856, E-ISSN 1572-8102, Vol. 24, no 1, p. 25-43Article in journal (Refereed)
  • 210.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Jonsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Nilsson, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    d'Orso, Julien
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Saksena, Mayank
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Regular model checking for LTL(MSO)2012In: International Journal on Software Tools for Technology Transfer (STTT), ISSN 1385-4879, E-ISSN 1571-8115, Vol. 14, no 2, p. 223-241Article in journal (Refereed)
    Abstract [en]

    Regular model checking is a form of symbolic model checking for parameterized and infinite-state systems whose states can be represented as words of arbitrary length over a finite alphabet, in which regular sets of words are used to represent sets of states. We present LTL(MSO), a combination of the logics MSO and LTL as a natural logic for expressing temporal properties to be verified in regular model checking. In other words, LTL(MSO) is a natural specification language for both the system and the property under consideration. LTL(MSO) is a two-dimensional modal logic, where MSO is used for specifying properties of system states and transitions, and LTL is used for specifying temporal properties.  In addition, the first-order quantification in MSO can be used to express properties parameterized on a position or process.  We give a technique for model checking LTL(MSO), which is adapted from the automata-theoretic approach: a formula is translated to a Buechi regular transition system with a regular set of accepting states, and regular model checking techniques are used to search for models. We have implemented the technique, and show its application to a number of parameterized algorithms from the literature.

  • 211.
    Abdulla, Parosh
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Mahata, Pritha
    Datorteknik.
    Mayr, Richard
    Decidability of Zenoness, Token Liveness, and Boundedness for Dense-Timed Petri Nets.2004In: FSTTCS' 04: 24th Conference on Foundations of Software Technology and Theoretical Computer Science, 2004Conference paper (Refereed)
  • 212.
    Abdulla, Parosh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ouaknine, Joel
    Quaas, Karin
    Worrell, James
    Zone-Based Universality Analysis for Single-Clock Timed Automata2007In: International Symposium on Fundamentals of Software Engineering, Proceedings / [ed] Arbab F; Sirjani M, 2007, p. 98-112Conference paper (Refereed)
    Abstract [en]

    During the last years, timed automata have become a popular model for describing the behaviour of real-time systems. In particular, there has been much research on problems such as language inclusion and universality. It is well-known that the universality problem is undecidable for the class of timed automata with two or more clocks. Recently, it was shown that the problem becomes decidable if the automata are restricted to operate on a single clock variable. However, existing algorithms use a region-based constraint system and suffer from constraint explosion even for small examples. In this paper, we present a zone-based algorithm for solving the universality problem for single-clock timed automata. We apply the theory of better quasi-orderings, a refinement of the theory of well quasi-orderings, to prove termination of the algorithm. We have implemented a prototype based on our method, and checked universality for a number of timed automata. Comparisons with a region-based prototype confirm that zones are a more succinct representation, and hence allow a much more efficient implementation of the universality algorithm.

  • 213.
    Abdullah, Jakaria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Mohaqeqi, Morteza
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Yi, Wang
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Synthesis of Ada code from graph-based task models2017In: Proc. 32nd ACM Symposium on Applied Computing, New York: ACM Press, 2017, p. 1467-1472Conference paper (Refereed)
  • 214.
    Abdullah Jan, Mirza
    et al.
    Linköping University, Department of Electrical Engineering.
    Ahsan, Mahmododfateh
    Linköping University, Department of Electrical Engineering.
    Multi-View Video Transmission over the Internet2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    3D television using multiple views rendering is receiving increasing interest. In this technology a number of video sequences are transmitted simultaneously and provides a larger view of the scene or stereoscopic viewing experience. With two views stereoscopic rendition is possible. Nowadays 3D displays are available that are capable of displaying several views simultaneously and the user is able to see different views by moving his head.

    The thesis work aims at implementing a demonstration system with a number of simultaneous views. The system will include two cameras, computers at both the transmitting and receiving end and a multi-view display. Besides setting up the hardware, the main task is to implement software so that the transmission can be done over an IP-network.

    This thesis report includes an overview and experiences of similar published systems, the implementation of real time video, its compression, encoding, and transmission over the internet with the help of socket programming and finally the multi-view display in 3D format.  This report also describes the design considerations more precisely regarding the video coding and network protocols.

  • 215. Abdullah, Matin
    et al.
    Feig, Michael
    Pettitt, Montgomery
    Johnsson, Lennart
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for High Performance Computing, PDC.
    SimDB: A Problem Solving Environment for Molecular Dynamics Simulation and Analysis2000Conference paper (Refereed)
    Abstract [en]

    The design of a software environment, SimDB, for molecular dynamics simulation and analysis is presented as an example of virtual laboratories enabled by high-speed networks connecting substantial computing and storage resources with more modest local compuation and visualization resources available to research groups. SimDB includes large-scale, dynamic, distributed data repositories. The simulated data sets, trajectories, are usually interpreted through reduced data sets, processed data sets, calculated by analysis functions. Both trajectory data and processed data are saved, but in differnt data bases, with processed data bases having several smaller objects for each trajectory. A browser based user interface with a well defined API allows for a wide array of analysis functions. Analysis functions are executed only if the requested analysis result is not available. The ability to incorporate user defined functions is a critical feature of SimDB.

  • 216.
    Abdullah, Nazri
    et al.
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS.
    Håkansson, Anne
    KTH, School of Information and Communication Technology (ICT), Software and Computer systems, SCS.
    Moradian, E.
    Blockchain based approach to enhance big data authentication in distributed environment2017In: 2017 Ninth International Conference on Ubiquitous and Future Networks (ICUFN), IEEE Computer Society, 2017, p. 887-892Conference paper (Refereed)
    Abstract [en]

    Existing authentication protocols for Big Data system such as Apache Hadoop is based on Kerberos. In the Kerberos protocol, there are numerous security issues that have remained unsolved; replay attacks, DDoS and single point of failure are some examples. These indicate potential security vulnerabilities and Big Data risks in using Hadoop. This paper presents drawbacks of Kerberos implementations and identifies authentication requirements that can enhance the security of Big Data in distributed environments. The enhancement proposed is based on the rising technology of blockchain that overcomes shortcomings of Kerberos.

  • 217.
    Abdullah, Syed Md Jakaria
    Mälardalen University, School of Innovation, Design and Engineering.
    Virtual Clustered-based Multiprocessor Scheduling in Linux Kernel2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recent advancements of multiprocessor architectures have led to increasing use of multiprocessors in real-time embedded systems. The two most popular real-time scheduling approaches in multiprocessors are global and partitioned scheduling. Cluster based multiprocessor scheduling can be seen as a hybrid approach combining benefits of both partitioned and global scheduling. Virtual clustering further enhances it by providing dynamic cluster resource allocation duringrun-time and applying hierarchical scheduling to ensure temporal isolation between different software components. Over the years, the study of virtual clustered-based multiprocessor scheduling has been limited to theoretical analysis. In this thesis, we implemented a Virtual-Clustered Hierarchical Scheduling Framework (VC-HSF) in Linux without modifying the base Linux kernel. This work includes complete design, implementation and experimentation of this framework in a multiprocessor platform. Our main contributions are twofold: (i) to the best of our knowledge, our work is the first implementation of any virtual-clustered real-time multiprocessor scheduling in an operating system, (ii) our design and implementation gives practical insights about challenges of implementing any virtual-clustered algorithms for real-time scheduling.

  • 218.
    Abdullah, Syed Md Jakaria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Lampka, Kai
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Yi, Wang
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Improving performance by monitoring while maintaining worst-case guarantees2016In: Proc. 19th Conference on Design, Automation and Test in Europe, Piscataway, NJ: IEEE, 2016, p. 257-260Conference paper (Refereed)
  • 219.
    Abdullahi, Abdille
    Växjö University, Faculty of Mathematics/Science/Technology, School of Mathematics and Systems Engineering.
    Component-based Software development2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Component-based Software development is a promising way to improve quality, time to market and handle the increasing complexity of software management. However, The component-based development is still a process with many problems, it is not well de_ned either from theoretical or practical point of view. This thesis gives a brief overview of Component-Based Software development and starts with brief historical evolution followed by a general explanation of the method. A detailed discussion of the underlying principles like components, component framework and compent system architecture are then presented. Some real world component stadards such as .net framework, CORBA CCM and EJB are given in detail. Finally, simple fille-sharing-program based on Apache's Avalon framework and another one based on .net framework are developed as a case study.

  • 220. Abdulle, A.
    et al.
    Engquist, Björn
    Mathematics Department, University of Texas at Austin.
    Finite element heterogeneous multiscale methods with near optimal computational complexity2007In: Multiscale Modeling & simulation, ISSN 1540-3459, E-ISSN 1540-3467, Vol. 6, no 4, p. 1059-1084Article in journal (Refereed)
    Abstract [en]

    This paper is concerned with a numerical method for multiscale elliptic problems. Using the framework of the heterogeneous multiscale methods (HMM), we propose a micro-macro approach which combines the finite element method (FEM) for the macroscopic solver and the pseudospectral method for the microsolver. Unlike the micro-macromethods based on the standard FEM proposed so far, in the HMM we obtain, for periodic homogenization problems, a method that (slow) variable.

  • 221.
    Abdulrazak Kadhim, Duaa
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Improving Electronic Health Records for Non-Swedish Speaking Refugees: A Qualitative Case Study2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Information and communication technology is used in healthcare in Sweden to improve health quality. Electronic Health Records are one of the technologies in healthcare which can increase a patient’s involvement in his/her healthcare and decision-making related to it. The patient can discuss the treatments, analyses and medical information stored in Electronic Health Records. The aim in this study is to investigate how the Electronics Health Records can be improved to motivate refugees in Sweden who cannot speak Swedish. This research is a qualitative interpretive case study. The methods used in this study are observation and interviews. Thematic analysis was used for data analysis. The findings show that refugees don’t receive information or instructions about how to use electronic health records properly. The language is the biggest hurdle to use electronic health records for refugee patients without knowing Swedish language. The findings further show that the electronic health records can be improved by adding sound or translated medical information in the diagnosis part of the electronic health record. This research might contribute to the healthcare process of any country in the world which has refugees and they use electronic health records.

     

  • 222.
    Abedan Kondori, Farid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Yousefi, Shahrouz
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Head operated electric wheelchair2014In: IEEE Southwest Symposium on Image Analysis and Interpretation (SSIAI 2014), IEEE , 2014, p. 53-56Conference paper (Refereed)
    Abstract [en]

    Currently, the most common way to control an electric wheelchair is to use joystick. However, there are some individuals unable to operate joystick-driven electric wheelchairs due to sever physical disabilities, like quadriplegia patients. This paper proposes a novel head pose estimation method to assist such patients. Head motion parameters are employed to control and drive an electric wheelchair. We introduce a direct method for estimating user head motion, based on a sequence of range images captured by Kinect. In this work, we derive new version of the optical flow constraint equation for range images. We show how the new equation can be used to estimate head motion directly. Experimental results reveal that the proposed system works with high accuracy in real-time. We also show simulation results for navigating the electric wheelchair by recovering user head motion.

  • 223.
    Abedin, Md Reaz Ashraful
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bensch, Suna
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hellström, Thomas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Self-supervised language grounding by active sensing combined with Internet acquired images and text2017In: Proceedings of the Fourth International Workshop on Recognition and Action for Scene Understanding (REACTS2017) / [ed] Jorge Dias George Azzopardi, Rebeca Marf, Málaga: REACTS , 2017, p. 71-83Conference paper (Refereed)
    Abstract [en]

    For natural and efficient verbal communication between a robot and humans, the robot should be able to learn names and appearances of new objects it encounters. In this paper we present a solution combining active sensing of images with text based and image based search on the Internet. The approach allows the robot to learn both object name and how to recognise similar objects in the future, all self-supervised without human assistance. One part of the solution is a novel iterative method to determine the object name using image classi- fication, acquisition of images from additional viewpoints, and Internet search. In this paper, the algorithmic part of the proposed solution is presented together with evaluations using manually acquired camera images, while Internet data was acquired through direct and reverse image search with Google, Bing, and Yandex. Classification with multi-classSVM and with five different features settings were evaluated. With five object classes, the best performing classifier used a combination of Pyramid of Histogram of Visual Words (PHOW) and Pyramid of Histogram of Oriented Gradient (PHOG) features, and reached a precision of 80% and a recall of 78%.

  • 224.
    Abedin, Md. Zainal
    et al.
    University of Science and Technology Chittagong.
    Chowdhury, Abu Sayeed
    University of Science and Technology Chittagong.
    Hossain, Mohammad Shahadat
    University of Chittagong, Bangladesh.
    Andersson, Karl
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Karim, Razuan
    University of Science and Technology Chittagong.
    An Interoperable IP based WSN for Smart Irrigation Systems2017Conference paper (Refereed)
    Abstract [en]

    Wireless Sensor Networks (WSN) have been highly developed which can be used in agriculture to enable optimal irrigation scheduling. Since there is an absence of widely used available methods to support effective agriculture practice in different weather conditions, WSN technology can be used to optimise irrigation in the crop fields. This paper presents architecture of an irrigation system by incorporating interoperable IP based WSN, which uses the protocol stacks and standard of the Internet of Things paradigm. The performance of fundamental issues of this network is emulated in Tmote Sky for 6LoWPAN over IEEE 802.15.4 radio link using the Contiki OS and the Cooja simulator. The simulated results of the performance of the WSN architecture presents the Round Trip Time (RTT) as well as the packet loss of different packet size. In addition, the average power consumption and the radio duty cycle of the sensors are studied. This will facilitate the deployment of a scalable and interoperable multi hop WSN, positioning of border router and to manage power consumption of the sensors.

  • 225.
    Abedin, Md. Zainal
    et al.
    University of Science and Technology, Chittagong.
    Paul, Sukanta
    University of Science and Technology, Chittagong.
    Akhter, Sharmin
    University of Science and Technology, Chittagong.
    Siddiquee, Kazy Noor E Alam
    University of Science and Technology, Chittagong.
    Hossain, Mohammad Shahadat
    University of Chittagong, Bangladesh.
    Andersson, Karl
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Selection of Energy Efficient Routing Protocol for Irrigation Enabled by Wireless Sensor Networks2017In: Proceedings of 2017 IEEE 42nd Conference on Local Computer Networks Workshops, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 75-81Conference paper (Refereed)
    Abstract [en]

    Wireless Sensor Networks (WSNs) are playing remarkable contribution in real time decision making by actuating the surroundings of environment. As a consequence, the contemporary agriculture is now using WSNs technology for better crop production, such as irrigation scheduling based on moisture level data sensed by the sensors. Since WSNs are deployed in constraints environments, the life time of sensors is very crucial for normal operation of the networks. In this regard routing protocol is a prime factor for the prolonged life time of sensors. This research focuses the performances analysis of some clustering based routing protocols to select the best routing protocol. Four algorithms are considered, namely Low Energy Adaptive Clustering Hierarchy (LEACH), Threshold Sensitive Energy Efficient sensor Network (TEEN), Stable Election Protocol (SEP) and Energy Aware Multi Hop Multi Path (EAMMH). The simulation is carried out in Matlab framework by using the mathematical models of those algortihms in heterogeneous environment. The performance metrics which are considered are stability period, network lifetime, number of dead nodes per round, number of cluster heads (CH) per round, throughput and average residual energy of node. The experimental results illustrate that TEEN provides greater stable region and lifetime than the others while SEP ensures more througput.

  • 226.
    Abedini, M.
    et al.
    Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran.
    Ahmadzadeh, Farzaneh
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Noorossana, R.
    Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran.
    Customer credit scoring using a hybrid data mining approach2016In: Kybernetes, ISSN 0368-492X, E-ISSN 1758-7883, Vol. 45, no 10, p. 1576-1588Article in journal (Refereed)
    Abstract [en]

    Purpose: A crucial decision in financial services is how to classify credit or loan applicants into good and bad applicants. The purpose of this paper is to propose a four-stage hybrid data mining approach to support the decision-making process. Design/methodology/approach: The approach is inspired by the bagging ensemble learning method and proposes a new voting method, namely two-level majority voting in the last stage. First some training subsets are generated. Then some different base classifiers are tuned and afterward some ensemble methods are applied to strengthen tuned classifiers. Finally, two-level majority voting schemes help the approach to achieve more accuracy. Findings: A comparison of results shows the proposed model outperforms powerful single classifiers such as multilayer perceptron (MLP), support vector machine, logistic regression (LR). In addition, it is more accurate than ensemble learning methods such as bagging-LR or rotation forest (RF)-MLP. The model outperforms single classifiers in terms of type I and II errors; it is close to some ensemble approaches such as bagging-LR and RF-MLP but fails to outperform them in terms of type I and II errors. Moreover, majority voting in the final stage provides more reliable results. Practical implications: The study concludes the approach would be beneficial for banks, credit card companies and other credit provider organisations. Originality/value: A novel four stages hybrid approach inspired by bagging ensemble method proposed. Moreover the two-level majority voting in two different schemes in the last stage provides more accuracy. An integrated evaluation criterion for classification errors provides an enhanced insight for error comparisons.

  • 227.
    Abefelt, Fredrik
    KTH, School of Information and Communication Technology (ICT).
    Synchronized audio playback over WIFI and Ethernet: A proof of concept multi-room audio playback system2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to develop an audio playback system, which can perform synchronized audio playback on multiple devices. Two different approaches for developing the system has been investigated, one using an already existing off the self product, and the other using an open source framework.

    The system developed is a proof-of-concept that can perform synchronized playback five devices, connected by Wi-Fi or Ethernet. The system developed can use Bluetooth devices or common media players as the sound source for the system.

  • 228. Abel, John H.
    et al.
    Drawert, Brian
    Hellander, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computational Science.
    Petzold, Linda R.
    GillesPy: A Python package for stochastic model building and simulation2016In: IEEE Life Sciences Letters, E-ISSN 2332-7685, Vol. 2, p. 35-38Article in journal (Refereed)
  • 229. Abela, D
    et al.
    Ritchie, H
    Ababneh, D
    Gavin, C
    Nilsson, Mats F
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Niazi, M Khalid Khan
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis.
    Carlsson, K
    Webster, WS
    The effect of drugs with ion channel-blocking activity on the early embryonic rat heart2010In: Birth defects research. Part B. Developmental and reproductice toxicology, ISSN 1542-9733, E-ISSN 1542-9741, Vol. 89, no 5, p. 429-440Article in journal (Refereed)
    Abstract [en]

    This study investigated the effects of a range of pharmaceutical drugs with ion channel-blocking activity on the heart of gestation day 13 rat embryos in vitro. The general hypothesis was that the blockade of the IKr/hERG channel, that is highly important for the normal functioning of the embryonic rat heart, would cause bradycardia and arrhythmia. Concomitant blockade of other channels was expected to modify the effects of hERG blockade. Fourteen drugs with varying degrees of specificity and affinity toward potassium, sodium, and calcium channels were tested over a range of concentrations. The rat embryos were maintained for 2 hr in culture, 1 hr to acclimatize, and 1 hr to test the effect of the drug. All the drugs caused a concentration-dependent bradycardia except nifedipine, which primarily caused a negative inotropic effect eventually stopping the heart. A number of drugs induced arrhythmias and these appeared to be related to either sodium channel blockade, which resulted in a double atrial beat for each ventricular beat, or IKr/hERG blockade, which caused irregular atrial and ventricular beats. However, it is difficult to make a precise prediction of the effect of a drug on the embryonic heart just by looking at the polypharmacological action on ion channels. The results indicate that the use of the tested drugs during pregnancy could potentially damage the embryo by causing periods of hypoxia. In general, the effects on the embryonic heart were only seen at concentrations greater than those likely to occur with normal therapeutic dosing.

  • 230.
    Abelli, Björn
    University of Borås, School of Business and IT.
    Directing and Enacting the Information System2007In: Advances in Information Systems Development - New Methods and Practice for the Networked Society. / [ed] W Wojtkowski, W. G. Wojtkowski, J. Zupancic, G. Magyar, G. Knapp, Springer US , 2007, p. 13-23Chapter in book (Other academic)
  • 231.
    Abelli, Björn
    Mälardalen University, School of Business.
    Directing and Enacting the Information System2006In: Advances in Information Systems Development: New Methods and Practice for the Networked Society, Volume 2, Issue PART 2, 2006, p. 13-23Conference paper (Refereed)
  • 232.
    Abelli, Björn
    Mälardalen University, School of Business.
    Enacting the e-Society2006In: Proceedings of the IADIS International Conference e-Society 2006, 2006, p. 285-298Conference paper (Refereed)
  • 233.
    Abelli, Björn
    University of Borås, School of Business and IT.
    On Stage! Playwriting, Directing and Enacting the Informing Processes2007Doctoral thesis, monograph (Other academic)
  • 234.
    Abelli, Björn
    Mälardalen University, School of Business.
    Programmeringens grunder - med exempel i C#2004Book (Other (popular science, discussion, etc.))
    Abstract [en]

    Detta är en lärobok i grundläggande programmering. Den fokuserar på att lära ut det som är gemensamt för de flesta programmeringsspråk – de grundläggande elementen och programkonstruktionerna och hur dessa relaterar till varandra, oberoende av språket. Vilket språk programmet skrivs i måste vara underordnat den uppgift programmet skall lösa. Boken går därför igenom grunderna i strukturerad programmering och visar otaliga exempel i såväl flödesdiagram, strukturdiagram, pseudokod som i källkod. I slutet av boken finns kapitel som går igenom grunderna även i objektorienterad programmering.

    Boken tonar ner inlärningen av ett specifikt programmeringsspråk, men i slutändan måste program ändå skrivas i något språk. Exemplen är skrivna i C# som har slagit igenom som ett praktiskt programmeringsspråk på mycket kort tid och redan börjat göra sitt intåg i högskolekurser i programmering.

    I första hand är boken avsedd för nybörjare i programmering på högskolenivå, som vill lära sig programmeringens grunder.

  • 235.
    Abelli, Björn
    et al.
    Mälardalen University, School of Business.
    Révay, Péter
    Mälardalen University, School of Business.
    To Be or Not To Be Computer Based2004In: Proceedings of microCAD 2004, 2004, p. 1-8Conference paper (Refereed)
  • 236.
    Abenius, Erik
    KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
    Time-Domain Inverse Electromagnetic Scattering using FDTD and Gradient-based Minimization2004Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    The thesis addresses time-domain inverse electromagneticscattering for determining unknown characteristics of an objectfrom observations of the scattered .eld. Applications includenon-destructive characterization of media and optimization ofmaterial properties, for example the design of radar absorbingmaterials.A nother interesting application is the parameteroptimization of subcell models to avoid detailed modeling ofcomplex geometries.

    The inverse problem is formulated as an optimal controlproblem where the cost function to be minimized is thedi.erence between the estimated and observed .elds, and thecontrol parameters are the unknown object characteristics. Theproblem is solved in a deterministic gradient-basedoptimization algorithm using a parallel 2D FDTD scheme for thedirect problem.This approach is computationally intensive sincethe direct problem needs to be solved in every optimizationiteration in order to compute an estimated .eld.H ighlyaccurate analytical gradients are computed from the adjointformulation.In addition to giving better accuracy than .nitedi.erences, the analytical gradients also have the advantage ofonly requiring one direct and one adjoint problem to be solvedregardless of the number of parameters.

    When absorbing boundary conditions are used to truncate thecomputational domain, the equations are non-reversible and theentire time-history of the direct solution needs to be storedfor the gradient computation.Ho wever, using an additionaldirect simulation and a restart procedure it is possible tokeep the storage at an acceptable level.

    The inverse method has been successfully applied to a widerange of industrial problems within the European project,IMPACT (Inverse Methods for Wave Propagation Applications inTime-Domain).T he results presented here includecharacterization of layered dispersive media, determination ofparameters in subcell models for thin sheets and narrow slotsand optimization problems where the observed .eld is given bydesign objectives.

  • 237. Abenius, Erik
    et al.
    Andersson, Ulf
    Edelvik, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Eriksson, Lasse
    Ledfelt, Gunnar
    Hybrid time domain solvers for the Maxwell equations in 2D2002In: International Journal for Numerical Methods in Engineering, ISSN 0029-5981, E-ISSN 1097-0207, Vol. 53, p. 2185-2199Article in journal (Refereed)
  • 238.
    Abenius, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Edelvik, Fredrik
    Thin Sheet Modeling Using Shell Elements in the Finite-Element Time-Domain Method2006In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 54, p. 28-34Article in journal (Refereed)
  • 239.
    Abenius, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Johansson, Christer
    A General Approach for Time-Domain Simulation of Waveguides in 3D2004In: Proc. EMB 04, Computational Electromagnetics: Methods and Applications, Göteborg, Sweden: Department of Electromagnetics, Chalmers University of Technology , 2004, p. 220-226Conference paper (Other academic)
  • 240.
    Abenius, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Johansson, Christer
    Modeling of inhomogeneous waveguides using hybrid methods2005Manuscript (preprint) (Other academic)
  • 241.
    Abenius, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Strand, Bo
    Solving inverse electromagnetic problems using FDTD and gradient-based minimization2006In: International Journal for Numerical Methods in Engineering, ISSN 0029-5981, E-ISSN 1097-0207, Vol. 68, p. 650-673Article in journal (Refereed)
  • 242. Abenius, Erik
    et al.
    Strand, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Alestra, Stephane
    Inverse Electromagnetic Scattering Using the Finite-Difference Time-Domain Method2000In: Proc. Millennium Conference on Antennas and Propagation, Noordwijk, The Netherlands: ESA Publications , 2000, p. 4-Conference paper (Refereed)
  • 243.
    Abensour Sellström, Gabriel
    et al.
    KTH, School of Computer Science and Communication (CSC).
    Runefelt Tõnisson, Meidi
    KTH, School of Computer Science and Communication (CSC).
    Analysis of Voting Algorithms: a comparative study of the Single Transferable Vote.2012Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A voting system is defined as a procedure through which political power is distributed among candidates - from the ballot box to the parliament. This essay specifically seeks to contrast the Single Transferable Vote system with two other voting algorithms (Modified Sainte-Laguë and First-Past-The-Post), by constructing Java implementations of the algorithms and running example data through them. Thus, the suitability of a possible real-life implementation of the Single Transferable Vote method in a Swedish parliament context is evaluated. Furthermore, an alternative version of the original STV method which has been modified to fit these conditions is suggested. The effects of such an implementation on election outcomes are not entirely conclusive, and the conclusion is that more research is needed before a definite evaluation can be made.

  • 244. Aberer, André
    et al.
    Stamatakis, Alexis
    Ronquist, Fredrik
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    An efficient independence sampler for updating branches in Bayesian Markov chain Monte Carlo sampling of phylogenetic trees2016In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 65, no 1, p. 161-176Article in journal (Refereed)
  • 245. Aberer, Karl
    et al.
    Onana Alima, Luc
    RISE, Swedish ICT, SICS.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS.
    Girdzijauskas, Sarunas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hauswirth, Manfred
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    The essence of P2P: A reference architecture for overlay networks2005Conference paper (Refereed)
    Abstract [en]

    The success of the P2P idea has created a huge diversity of approaches, among which overlay networks, for example, Gnutella, Kazaa, Chord, Pastry, Tapestry, P-Grid, or DKS, have received specific attention from both developers and researchers. A wide variety of algorithms, data structures, and architectures have been proposed. The terminologies and abstractions used, however, have become quite inconsistent since the P2P paradigm has attracted people from many different communities, e.g., networking, databases, distributed systems, graph theory, complexity theory, biology, etc. In this paper we propose a reference model for overlay networks which is capable of modeling different approaches in this domain in a generic manner. It is intended to allow researchers and users to assess the properties of concrete systems, to establish a common vocabulary for scientific discussion, to facilitate the qualitative comparison of the systems, and to serve as the basis for defining a standardized API to make overlay networks interoperable.

  • 246. Abeywardena, D.
    et al.
    Wang, Zhan
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Dissanayake, G.
    Waslander, S. L.
    Kodagoda, S.
    Model-aided state estimation for quadrotor micro air vehicles amidst wind disturbances2014Conference paper (Refereed)
    Abstract [en]

    This paper extends the recently developed Model-Aided Visual-Inertial Fusion (MA-VIF) technique for quadrotor Micro Air Vehicles (MAV) to deal with wind disturbances. The wind effects are explicitly modelled in the quadrotor dynamic equations excluding the unobservable wind velocity component. This is achieved by a nonlinear observability of the dynamic system with wind effects. We show that using the developed model, the vehicle pose and two components of the wind velocity vector can be simultaneously estimated with a monocular camera and an inertial measurement unit. We also show that the MA-VIF is reasonably tolerant to wind disturbances, even without explicit modelling of wind effects and explain the reasons for this behaviour. Experimental results using a Vicon motion capture system are presented to demonstrate the effectiveness of the proposed method and validate our claims.

  • 247. Abeywickrama, S.
    et al.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Faculty of Electrical Engineering and Computing, Dept. of Telecommunications, Croatia.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Nag, A.
    Wong, E.
    Dual-homing based protection for enhanced network availability and resource efficiency2014In: Asia Communications and Photonics Conference, ACP, 2014Conference paper (Refereed)
    Abstract [en]

    An approach to enhance core network survivability by utilizing dual-homing capabilities of the access network. Results reveal significant improvements in core network resource utilization and connection availability, suggesting benefits to network operators and service providers.

  • 248.
    Abghari, Shahrooz
    et al.
    Blekinge Institute of Technology, School of Computing.
    Kazemi, Samira
    Blekinge Institute of Technology, School of Computing.
    Open Data for Anomaly Detection in Maritime Surveillance2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Context: Maritime Surveillance (MS) has received increased attention from a civilian perspective in recent years. Anomaly detection (AD) is one of the many techniques available for improving the safety and security in the MS domain. Maritime authorities utilize various confidential data sources for monitoring the maritime activities; however, a paradigm shift on the Internet has created new sources of data for MS. These newly identified data sources, which provide publicly accessible data, are the open data sources. Taking advantage of the open data sources in addition to the traditional sources of data in the AD process will increase the accuracy of the MS systems. Objectives: The goal is to investigate the potential open data as a complementary resource for AD in the MS domain. To achieve this goal, the first step is to identify the applicable open data sources for AD. Then, a framework for AD based on the integration of open and closed data sources is proposed. Finally, according to the proposed framework, an AD system with the ability of using open data sources is developed and the accuracy of the system and the validity of its results are evaluated. Methods: In order to measure the system accuracy, an experiment is performed by means of a two stage random sampling on the vessel traffic data and the number of true/false positive and negative alarms in the system is verified. To evaluate the validity of the system results, the system is used for a period of time by the subject matter experts from the Swedish Coastguard. The experts check the detected anomalies against the available data at the Coastguard in order to obtain the number of true and false alarms. Results: The experimental outcomes indicate that the accuracy of the system is 99%. In addition, the Coastguard validation results show that among the evaluated anomalies, 64.47% are true alarms, 26.32% are false and 9.21% belong to the vessels that remain unchecked due to the lack of corresponding data in the Coastguard data sources. Conclusions: This thesis concludes that using open data as a complementary resource for detecting anomalous behavior in the MS domain is not only feasible but also will improve the efficiency of the surveillance systems by increasing the accuracy and covering some unseen aspects of maritime activities.

  • 249.
    Abheeshta, Putta
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Comparative Analysis of Software Development Practices across Software Organisations: India and Sweden2016Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context. System Development Methodologies (SDM’s) have been an area of intensive research in the field of software engineering. Different software organisations adopt different development methodologies and use different development practices. The frequency of usage of development practices and acceptance factors for adoption of development methodology are crucial for software organisations. The factors of acceptance and development practices differ across geographical locations. Many challenges have been presented in the literature with respect to the mismatch of the development practices across organisations while collaborating across organisations in distributed development. There is no considerable amount of research done in context of differences across development practices and acceptance factors for adoption of a particular development methodology. Objectives. The primary objectives of the research are to find out a) differences in (i) practice usage (ii) acceptance factors such as organisational, social and cultural b) explore the reasons for the differences and also investigate consequences of such differences while collaborating, across organisations located in India and Sweden. Methods. A literature review was conducted by searching in scientific databases for identifying common agile and plan-driven development practices and acceptance theories for development methodologies. Survey was conducted across organisations located in India and Sweden to find out the usage frequency of development practices and acceptance factors. Ten interviews were conducted to investigate, reasons for differences and consequences of differences from the software practitioners from organisations located in India and Sweden. Literature evidences were used to support the results collected from interviews. Results. From the survey, organisations in India have adopted a higher frequency of plan driven practices when compared to Sweden and agile practices were adopted at higher frequency in Sweden when compared to India. The number of organisations adopting "pure agile" methodologies have been significantly higher in Sweden. There was significant differences were found across the acceptance factors such as cultural, organisational, image and career factors between India and Sweden. The factors such as cultural, social, human, business and organisational factors are responsible for such differences across development practices and acceptance factors. Challenges related to communication, coordination and control were found due to the differences, while collaborating between Indian and Sweden sites. Conclusions. The study signifies the importance of identifying the frequency of development practices and also the acceptance factors responsible for adoption of development methodologies in the software organisations. The mismatch between these practices will led to various challenges. The study draws insights into various non-technical factors such as cultural, human, organisational, business and social while collaborating between organisations. Variations across these factors will lead to many coordination, communication and control issues. Keywords: Development Practices, Agile Development, Plan Driven Development, Acceptance Factors, Global Software Development.

  • 250. Abiala, Kristina
    et al.
    Hernwall, Patrik
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Tweens konstruerar identitet online – flickors och pojkars erfarenheter av sociala medier2013In: Pedagogisk forskning i Sverige, ISSN 1401-6788, E-ISSN 2001-3345, Vol. 18, no 1-2Article in journal (Refereed)
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