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  • 251.
    Bocharova, Irina
    et al.
    St.-Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Kudryashov, Boris
    St.-Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Lyamin, Nikita
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Frick, Erik
    AstaZero Hällered, Sandhult, Sweden.
    Rabi, Maben
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Department of Electrical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
    Low Delay Inter-Packet Coding in Vehicular Networks2019In: Future Internet, ISSN 1999-5903, E-ISSN 1999-5903, Vol. 11, no 12, article id 212Article in journal (Refereed)
    Abstract [en]

    In Cooperative Intelligent Transportation Systems (C-ITSs), vehicles need to wirelessly connect with Roadside units (RSUs) over limited durations when such point-to-point connections are possible. One example of such communications is the downloading of maps to the C-ITS vehicles. Another example occurs in the testing of C-ITS vehicles, where the tested vehicles upload trajectory records to the roadside units. Because of real-time requirements, and limited bandwidths, data are sent as User Datagram Protocol (UDP) packets. We propose an inter-packet error control coding scheme that improves the recovery of data when some of these packets are lost; we argue that the coding scheme has to be one of convolutional coding. We measure performance through the session averaged probability of successfully delivering groups of packets. We analyze two classes of convolution codes and propose a low-complexity decoding procedure suitable for network applications. We conclude that Reed–Solomon convolutional codes perform better than Wyner–Ash codes at the cost of higher complexity. We show this by simulation on the memoryless binary erasure channel (BEC) and channels with memory, and through simulations of the IEEE 802.11p DSRC/ITS-G5 network at the C-ITS test track AstaZero.

  • 252.
    Bocharova, Irina
    et al.
    Department of Information Systems, St. Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & Institute of Computer Science, University of Tartu, Estonia.
    Kudryashov, Boris
    Department of Information Systems, St. Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & Institute of Computer Science, University of Tartu, Estonia.
    Rabi, Maben
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Lyamin, Nikita
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Dankers, Wouter
    Volvo GTT, Goteborg, Sweden.
    Frick, Erik
    AstaZero, Hällered, Sandhult, Sweden.
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Department of Electrical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
    Characterizing Packet Losses in Vehicular Networks2019In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 68, no 9, p. 8347-8358Article in journal (Refereed)
    Abstract [en]

    To enable testing and performance evaluation of new connected and autonomous driving functions, it is important to characterize packet losses caused by degradation in vehicular (V2X) communication channels. In this paper we suggest an approach to constructing packet loss models based on the socalled Pseudo-Markov chains (PMC). The PMC based model needs only short training sequences, has low computational complexity, and yet provides more precise approximations than known techniques. We show how to learn PMC models from either empirical records of packet receptions, or from analytical models of fluctuations in the received signal strength. In particular, we validate our approach by applying it on (i) V2X packet reception data collected from an active safety test run, which used the LTE network of the AstaZero automotive testing site in Sweden, and (ii) variants of the Rician fading channel models corresponding to two models of correlations of packet losses. We also show that initializing the Baum-Welch algorithm with a second order PMC model leads to a high accuracy model. © 2019 IEEE.

  • 253.
    Bocharova, Irina
    et al.
    ITMO University, Saint Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Kudryashov, Boris
    ITMO University, Saint Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Rabi, Maben
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Lyamin, Nikita
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Dankers, Wouter
    Volvo GTT, Göteborg, Sweden.
    Frick, Erik
    AstaZero, Hällered, Sweden.
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Modeling Packet Losses in Communication Networks2019In: 2019 IEEE International Symposium on Information Theory: Proceedings, 2019, p. 1012-1016Conference paper (Refereed)
    Abstract [en]

    An approach to constructing discrete models of packet losses suitable for a wide variety of communication network applications is studied. It is based on estimating parameters of probabilistic automata described via so-called pseudo-Markov chains. The new technique is applied both to approximating a discrete time analog process at the output of known channel models and to the experimental data stream. Comparison of models is performed by computing probabilities of more than m losses out of n transmitted packets (P (m, n)). It is shown that for the Rician fading channel with exponential correlation and correlation determined by a Bessel filter, the obtained rank-two and rank-three discrete modes, respectively, provide high accuracy coincidence of P (m, n) performances. The rank-three discrete model computed on the experimental data stream obtained from the LTE network provides significantly better approximation of P (≥ m, n) performance than that obtained by the Baum-Welch algorithm.

  • 254.
    Boeira, Felipe
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Federal University of Rio Grande do Sul, Porto Alegre, Brazil & Linköping University, Linköping, Sweden.
    Barcellos, Marinho P.
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Pignaton de Freitas, Edison
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Asplund, Mikael
    Linköping University, Linköping, Sweden.
    Effects of Colluding Sybil Nodes in Message Falsification Attacks for Vehicular Platooning2017In: 2017 IEEE Vehicular Networking Conference (VNC) / [ed] Onur Altintas, Claudio Casetti, Nicholas Kirsch, Renato Lo Cigno & Rui Meireles, 2017Conference paper (Refereed)
    Abstract [en]

    This paper studies the impact of vulnerabilities associated with the Sybil attack (through falsification of multiple identities) and message falsification in vehicular platooning. Platooning employs Inter-Vehicular Communication (IVC) to control a group of vehicles. It uses broadcast information such as acceleration, position, and velocity to operate a longitudinal control law. Cooperation among vehicles allows platoons to reduce fuel consumption and risks associated with driver mistakes. In spite of these benefits, the use of network communication to control vehicles exposes a relevant attack surface that can be exploited by malicious actors. To carry out this study, we evaluate five scenarios to quantify the potential impact of such attacks, identifying how platoons behave under varying Sybil attack conditions and what are the associated safety risks. This research also presents the use of location hijacking attack. In this attack, innocent vehicles that are not part of a platoon are used as a way to create trust bond between the false identities and the physical vehicles. We demonstrate that the ability to create false identities increases the effectiveness of message falsification attacks by making them easier to deploy and harder to detect in time.

  • 255.
    Boeira, Felipe
    et al.
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Barcellos, Marinho
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Pignaton de Freitas, Edison
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Asplund, Mikael
    Linköping University, Linköping, Sweden.
    On the impact of sybil attacks in cooperative driving scenarios2017In: 2017 IFIP Networking Conference (IFIP Networking) and Workshops, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    Platooning employs a set of technologies to manage how a group of vehicles operates, including radar, GPS and Inter-Vehicular Communication (IVC). It uses broadcasted information such as acceleration, position and velocity to operate vehicle members of the platoon. Cooperation among vehicles allows platoons to reduce fuel consumption and risks associated with driver mistakes. In spite of these benefits, the use of IVC to control vehicles exposes a relevant attack surface that can be exploited by malicious actors. In this paper we study the impact of vulnerabilities associated with the Sybil attack (through falsification of multiple identities) and message falsification in vehicular platooning. Simulation results show that this attack may impact the longitudinal control and compromise the entire platoon control. © Copyright 2018 IEEE

  • 256.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    On Option-Valuation in Illiquid Markets: Invariant Solutions to a Nonlinear Model2008In: Mathematical control theory and finance / [ed] Andrey Sarychev; et al, Berlin: Springer Berlin/Heidelberg, 2008, p. 71-94Conference paper (Other academic)
    Abstract [en]

    The present model describes a perfect hedging strategy for a large trader. In this case the hedging strategy affects the price of the underlying security. The feedback-effect leads to a nonlinear version of the Black-Scholes partial differential equation. Using Lie group theory we reduce in special cases the partial differential equation to some ordinary differential equations. The Lie group found for the model equation gives rise to invariant solutions. Families of exact invariant solutions for special values of parameters are described. © 2008 Springer-Verlag Berlin Heidelberg.

  • 257.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Pricing options in illiquid markets: optimal systems, symmetry reductions and exact solutions2010In: Lobachevskii Journal of Mathematics, ISSN 1995-0802, E-ISSN 1818-9962, Vol. 31, no 2, p. 90-99Article in journal (Refereed)
    Abstract [en]

    We study a class of nonlinear pricing models which involves the feedback effect from the dynamic hedging strategies on the price of asset introduced by  Sircar and Papanicolaou. We are first to study the case of a nonlinear demand function involved in the model. Using a Lie group analysis we investigate the symmetry properties of these nonlinear diffusion equations. We provide the optimal systems of subalgebras and the complete set of non-equivalent reductions of studied PDEs to ODEs. In most cases we obtain families of exact solutions or derive particular solutions to the equations.

  • 258.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Study of the risk-adjusted pricing methodology model with methods of geometrical analysis2011In: Stochastics: An International Journal of Probablitiy and Stochastic Processes, ISSN 1744-2508, E-ISSN 1744-2516, Vol. 83, no 4-6, p. 333-345Article in journal (Refereed)
    Abstract [en]

    Families of exact solutions are found to a nonlinear modification of the Black-Scholes equation. This risk-adjusted pricing methodology model (RAPM) incorporates both transaction costs and the risk from a volatile portfolio. Using the Lie group analysis we obtain the Lie algebra admitted by the RAPM equation. It gives us the possibility to describe an optimal system of subalgebras and the corresponding set of invariant solutions to the model. In this way we can describe the complete set of possible reductions of the nonlinear RAPM model. Reductions are given in the form of different second order ordinary differential equations. In all cases we provide exact solutions to these equations in an explicit or parametric form. Each of these solutions contains a reasonable set of parameters which allows one to approximate a wide class of boundary conditions. We discuss the properties of these reductions and the corresponding invariant solutions.

  • 259.
    Bordag, Ljudmila A.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Symmetry reductions and exact solutions for nonlinear diffusion equations2009In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 24, no 8/9, p. 1713-1716Article in journal (Refereed)
    Abstract [en]

    The symmetry properties of nonlinear diffusion equations are studied using a Lie group analysis. Reductions and families of exact solutions are found for some of these equations.

    © 2009 World Scientific Publishing Company.

  • 260.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Applied Mathematics and Physics (CAMP).
    Chkhetiani, O. G.
    Space Research Institute, Russian Academy of Sciences.
    Frohner, M.
    Brandenburgische Technische Universität Cottbus.
    Myrnyy, V.
    Brandenburgische Technische Universität Cottbus.
    Interaction of a rotational motion and an axial flow in small geometries for a Taylor-Couette problem2005In: Journal of Fluids and Structures, ISSN 0889-9746, E-ISSN 1095-8622, Vol. 20, no 5, p. 621-641Article in journal (Refereed)
    Abstract [en]

    We analyze the stability of a Taylor-Couette flow under the imposition of a weak axial flow in the case of a very short cylinder with a narrow annulus gap. We consider an incompressible viscous fluid contained in the narrow gap between two concentric short cylinders, in which the inner cylinder rotates with constant angular velocity. The caps of the cylinders have narrow tubes conically tapering to very narrow slits, allowing an axial flow along the surface of the inner cylinder. The approximated solution for the Taylor-Couette flow for short cylinders was found and used for the stability analysis instead of the precise but bulky solution. The sensitivity of the Taylor-Couette flow to small perturbations and to weak axial flow was studied. We demonstrate that perturbations coming from the axial flow cause the propagation of dispersive waves in the Taylor-Couette flow. While in long cylinders the presence of an axial flow leads to the breaking of axial symmetry, in small cylinders it leads to the breaking of mirror symmetry. The coexistence of a rotation and an axial flow requires that, in addition to the energy and the angular momentum of the flow, the helicity must also be studied. The approximated form for the helicity formula in the case of short cylinders was derived. We found that the axial flow stabilizes the Taylor-Couette flow. The supercritical flow includes a rich variety of vortical structures, including a symmetric pair of Taylor vortices, an anomalous single vortex and quasiperiodic oscillating vortices. Pattern formation was studied at large for rated ranges of azimuthal and axial Reynolds numbers. A region where three branches of different states occur was localized. Numerical simulations in 3-D and in the axisymmetrical case of the model flow are presented, which illustrate the instabilities analyzed.

  • 261.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Chmakova, A. Y.
    Fakultät Mathematik, Naturwissenschaften und Informatik, Brandenburgische Technische Universität Cottbus, Cottbus, Germany.
    Explicit solutions for a nonlinear model of financial derivatives2007In: International Journal of Theoretical and Applied Finance, ISSN 0219-0249, Vol. 10, no 1, p. 1-21Article in journal (Refereed)
    Abstract [en]

    Families of explicit solutions are found to a nonlinear Black-Scholes equation which incorporates the feedback-effect of a large trader in case of market illiquidity. The typical solution of these families will have a payoff which approximates a strangle. These solutions were used to test numerical schemes for solving a nonlinear Black-Scholes equation. © World Scientific Publishing Company.

  • 262.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Frey, Rüdiger
    Leipzig University, Department of Mathematics.
    Pricing options in illiquid markets: symmetry reductions and exact solutions2008In: Nonlinear Models in Mathematical Finance: New Research Trends in Option Pricing / [ed] Matthias Ehrhardt, New York: Nova Science Publishers, Inc., 2008, p. 103-130Chapter in book (Other academic)
    Abstract [en]

    The present paper is concerned with nonlinear Black Scholes equations arising in certain option pricing models with a large trader and/or transaction costs. In the first part we give an overview of existing option pricing models with frictions. While the financial setup differs between models, it turns out that in many of these models derivative prices can be characterized by fully nonlinear versions of the standard parabolic Black-ScholesPDE. In the second part of the paper we study a typical nonlinear Black-Scholes equation using methods from Lie group analysis. The equation possesses a rich symmetry group. By introducing invariant variables,  invariant solutions can therefore be characterized in terms of solutions to ordinary differential equations. Finally we discuss properties and applications of these solutions.

  • 263.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Matveev, Sergey K.
    St. Petersburger State University.
    Berechnungen der Gleichgewichtslage der Welle unterpräzisierten geometrischen Voraussetzungen der Druckfluidströmung in LHS 7502009Report (Other academic)
  • 264.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Matveev, Sergey K.
    St. Petersburg State University.
    Erste  Berechnungen der Druckfluidströmung2008Report (Other academic)
  • 265.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Matveev, Sergey K.
    St. Petersburg State University.
    Präzisierte Berechnungender Druckfluidströmung in LHS 7502008Report (Other academic)
  • 266.
    Bordag, Ljudmila A.
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Mikaelyan, Anna
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Models of self-financing hedging strategies in illiquid markets: Symmetry reductions and exact solutions2011In: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, Vol. 96, no 1-3, p. 191-207Article in journal (Refereed)
    Abstract [en]

    We study the general model of self-financing trading strategies inilliquid markets introduced by Schoenbucher and Wilmott, 2000.A hedging strategy in the framework of this model satisfies anonlinear partial differential equation (PDE) which contains somefunction g(alpha). This function is deep connected to anutility function.

    We describe the Lie symmetry algebra of this PDE and provide acomplete set of reductions of the PDE to ordinary differentialequations (ODEs). In addition we are able to describe all types offunctions g(alpha) for which the PDE admits an extended Liegroup. Two of three special type functions lead to modelsintroduced before by different authors, one is new. We clarify theconnection between these three special models and the generalmodel for trading strategies in illiquid markets. We study withthe Lie group analysis the new special case of the PDE describingthe self-financing strategies. In both, the general model and thenew special model, we provide the optimal systems of subalgebrasand study the complete set of reductions of the PDEs to differentODEs. In all cases we are able to provide explicit solutions tothe new special model. In one of the cases the solutions describepower derivative products.

  • 267.
    Bordag, Michael
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Interaction of a charge with a thin plasma sheet2007In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 76, no 6, p. 065011-Article in journal (Refereed)
    Abstract [en]

    The interaction of the electromagnetic field with a two-dimensional plasma sheet intended to describe the pi-electrons of a carbon nanotube or a C-60 molecule is investigated. By first integrating out the displacement field of the plasma or the electromagnetic field, different representations for quantities like the Casimir energy are derived which are shown to be consistent with one another. Starting from the covariant gauge for the electromagnetic field, it is shown that the matching conditions to which the presence of the plasma sheet can be reduced are different from the commonly used ones. The difference in the treatments does not show up in the Casimir force between two parallel sheets, but it is present in the Casimir-Polder force between a charge or a neutral atom and a sheet. At once, since the plasma sheet is a regularization of the conductor boundary conditions, this sheds light on the difference in physics found earlier in the realization of conductor boundary conditions as "thin" or "thick" boundary conditions in Phys. Rev. D 70, 085010 (2004).

  • 268.
    Bordag, Michael
    et al.
    Leipzig University, Institute for Theoretical Physics, Leipzig, Germany.
    Jede, Ralf
    Raith GmbH, Dortmund, Germany.
    Montelius, Lars
    Lunds University, Physics Department, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Riu, Jordi
    University Rovira i Vergili, Taragona, Spain.
    Schmucker, Ulrich
    University Rovira i Vergili, Taragona, Spain.
    Zubtsov, Michael
    Fraunhofer Institute for Factory Automation, Magdeburg, Germany.
    Parallel nano-assembly directed by short-range field forces2006In: Proceedings of the 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Piscataway, United States: IEEE Press, 2006, p. 620-622, article id 4135031Conference paper (Refereed)
    Abstract [en]

    We present the ECs Sixth Framework Programme PARNASS project, which stands for 'Parallel nano assembling directed by short-range field forces' and represents a radical innovative approach to fabricating large volumes of hybrid nano electronic devices. The project combines in a synergy the 'top-down' and 'bottom-up' methods addressing one of the challenging physical and engineering problems of the very high accuracy over a large area. An array of specially designed nano-scale force field sources has to be a key part of this innovative approach to large-scale nano manufacturing. © 2006 IEEE.

  • 269.
    Bordag, Michael
    et al.
    Leipzig University, Vor Dem Hospitaltore 1, Leipzig, Germany.
    Nikolaev, Vladimir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Analytic corrections to the electromagnetic casimir interaction between a sphere and a plate at shortdistances2010In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 25, no 11, p. 2171-2176Article in journal (Refereed)
    Abstract [en]

    For the vacuum interaction of asphere in front of a plane,both obeying conductor boundary conditions, we consider the approximation of small separation. We derive the next-to-leading order of the asymptotic expansion in the separation-to-radius ratio epsilon. This correction is of order epsilon. In opposite to the scalar cases it contains also contributions proportional to logarithms in first and second order, epsilon ln epsilon and epsilon(ln epsilon)(2). We compare this result with the available findings of numerical and experimental approaches.

  • 270.
    Bordag, Michael
    et al.
    Leipzig University, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany.
    Nikolaev, Vladimir
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Beyond proximity force approximation in the casimir effect2009In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 24, no 8-9, p. 1743-1747Article in journal (Refereed)
    Abstract [en]

    We compare the analytical and numerical results for the Casimir force for the configuration of a plane and a cylinder in front of a plane. While for Dirichlet boundary conditions on both, plane and sphere or cylinder, agreement is found, for Neumann boundary conditions on either the plane or one of the two, cylinder or sphere, disagreement is found. This holds, for a sphere, also for different boundary conditions on the interacting surfaces. From recent, new numerical results for the cylinder, a general appearance of logarithmic contributions beyond PFA can be predicted.

  • 271.
    Bordag, Michael
    et al.
    Institute for Theoretical Physics, Leipzig University, Leipzig, Germany.
    Nikolaev, Vladimir
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Casimir force for a sphere in front of a plane beyond proximity force approximation2008In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 41, no 16, p. 164002-Article in journal (Refereed)
    Abstract [en]

    For the configuration of a sphere in front of a plane, we calculate the first two terms of the asymptotic expansion for small separation of the Casimir force. We consider both Dirichlet and Neumann boundary conditions.

  • 272.
    Bordag, Michael
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Nikolaev, Vladimir
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    First analytic correction beyond the proximity force approximation in the Casimir effect for the electromagnetic field in sphere-plane geometry2010In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 81, no 6, p. Article number 065011-Article in journal (Refereed)
    Abstract [en]

    We consider the vacuum energy for a configuration of a sphere in front of a plane, both obeying the conductor boundary condition, at small separation. For the separation becoming small we derive the first next-to-leading order of the asymptotic expansion in the separation-to-radius ratio epsilon. This correction is of order epsilon. Opposite to the scalar cases it contains also contributions proportional to logarithms in first and second order, epsilon ln epsilon and epsilon(ln epsilon)(2). We compare this result with the available findings of numerical and experimental approaches.

  • 273.
    Bordag, Michael
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Nikolaev, Vladimir
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    The vacuum energy for two cylinders with one increasing in size2009In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 42, no 41, p. 415203-Article in journal (Refereed)
    Abstract [en]

    We consider the vacuum energy for the configuration of two cylinders and obtain its asymptotic expansion if the radius of one of these cylinders becomes large while the radius of the other one and their separation are kept fixed. We calculate explicitly the next-to-leading order correction to the vacuum energy for the radius of the other cylinder becoming large or small.

  • 274.
    Bordag, Michael
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Applied Mathematics and Physics (CAMP).
    Ribayrol, Aline
    Lund University.
    Conache, Gabriela
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Applied Mathematics and Physics (CAMP).
    Fröberg, Linus E.
    Lund University.
    Gray, Struan
    Lund University.
    Samuelson, Lars
    Lund University.
    Montelius, Lars
    Lund University.
    Pettersson, Håkan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Applied Mathematics and Physics (CAMP).
    Shear stress measurements on InAs nanowires by AFM manipulation2007In: Small, ISSN 1613-6810, Vol. 3, no 8, p. 1398-1401Article in journal (Refereed)
    Abstract [en]

    On an upward curve? The curvature of an elastically deformed nanowire pinned to a flat surface contains information about the maximum static friction force, and hence the shear stress, between the nanowire and the surface. Here, InAs nanowires are bent in a controlled manner using the tip of an atomic force microscope (see image). The shear stress can be obtained from a simple analysis according to the standard theory of elasticity.

  • 275.
    Borschel, Christian
    et al.
    Institute for Solid State Physics, Jena University, Max-Wien-Platz 1, 07743 Jena, Germany.
    Messing, Maria
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Borgström, Magnus T.
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Paschoal, Waldomiro
    Avd. f. Fasta tillståndets fysik, Lunds Universitet / Tillämpad matematik och fysik (MPE-lab), MPE-lab.
    Wallentin, Jesper
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Kumar, Sandeep
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Mergenthaler, Kilian
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Deppert, Knut
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Canali, C. M.
    Högskolan i Kalmar.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Samuelson, Lars
    Avd. f. Fasta tillståndets fysik, Lunds Universitet.
    Ronning, Carsten
    Institute for Solid State Physics, Jena University, Max-Wien-Platz 1, 07743 Jena, Germany.
    A New Route toward Semiconductor Nanospintronics: Highly Mn-Doped GaAs Nanowires Realized by Ion-Implantation under Dynamic Annealing Conditions2011In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 11, no 9, p. 3935-3940Article in journal (Refereed)
    Abstract [en]

    We report on highly Mn-doped GaAs nanowires (NWs) of high crystalline quality fabricated by ion beam implantation, a technique that allows doping concentrations beyond the equilibrium solubility limit. We studied two approaches for the preparation of Mn-doped GaAs NWs: First, ion implantation at room temperature with subsequent annealing resulted in polycrystalline NWs and phase segregation of MnAs and GaAs. The second approach was ion implantation at elevated temperatures. In this case, the single-crystallinity of the GaAs NWs was maintained, and crystalline, highly Mn-doped GaAs NWs were obtained. The electrical resistance of such NWs dropped with increasing temperature (activation energy about 70 meV). Corresponding magnetoresistance measurements showed a decrease at low temperatures, indicating paramagnetism. Our findings suggest possibilities for future applications where dense arrays of GaMnAs nanowires may be used as a new kind of magnetic material system.

  • 276.
    Borschel, Christian
    et al.
    Institute for Solid State Physics, University of Jena, Jena, Germany.
    Messing, Maria
    Lund University, Lund, Sweden.
    Mergenthaler, Kilian
    Lund University, Lund, Sweden.
    Borgström, Magnus T.
    Lund University, Lund, Sweden.
    Paschoal, Waldomiro
    Lund University, Lund, Sweden.
    Wallentin, Jesper
    Lund University, Lund, Sweden.
    Kumar, Sandeep
    Lund University, Lund, Sweden.
    Deppert, Knut
    Lund University, Lund, Sweden.
    Canali, Carlo
    Linnaeus University, Kalmar, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Samuelson, Lars
    Lund University, Lund, Sweden.
    Ronning, Carsten
    Institute for Solid State Physics, University of Jena, Jena, Germany.
    A New Route towards Semiconductor Nanospintronics: Highly Mn-Doped GaAs Nanowires Realized by Ion-Implantation under Dynamic Annealing Conditions2011Conference paper (Refereed)
  • 277.
    Bosshard, Pascal Fabian
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Investigation of Trajectory Optimization for Multiple Car-Like Vehicles2015Report (Other academic)
  • 278.
    Bouguelia, Mohamed-Rafik
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Gonzalez, Ramon
    Robotic Mobility Group, Massachusetts Institute of Technology, Cambridge, USA.
    Iagnemma, Karl
    Robotic Mobility Group, Massachusetts Institute of Technology, Cambridge, USA.
    Byttner, Stefan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Unsupervised classification of slip events for planetary exploration rovers2017In: Journal of terramechanics, ISSN 0022-4898, E-ISSN 1879-1204, Vol. 73, p. 95-106Article in journal (Refereed)
    Abstract [en]

    This paper introduces an unsupervised method for the classification of discrete rovers' slip events based on proprioceptive signals. In particular, the method is able to automatically discover and track various degrees of slip (i.e. low slip, moderate slip, high slip). The proposed method is based on aggregating the data over time, since high level concepts, such as high and low slip, are concepts that are dependent on longer time perspectives. Different features and subsets of the data have been identified leading to a proper clustering, interpreting those clusters as initial models of the prospective concepts. Bayesian tracking has been used in order to continuously improve the parameters of these models, based on the new data. Two real datasets are used to validate the proposed approach in comparison to other known unsupervised and supervised machine learning methods. The first dataset is collected by a single-wheel testbed available at MIT. The second dataset was collected by means of a planetary exploration rover in real off-road conditions. Experiments prove that the proposed method is more accurate (up to 86% of accuracy vs. 80% for K-means) in discovering various levels of slip while being fully unsupervised (no need for hand-labeled data for training). © 2017 ISTVS

  • 279.
    Bouguelia, Mohamed-Rafik
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Karlsson, Alexander
    University of Skövde, Skövde, Sweden.
    Pashami, Sepideh
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Holst, Anders
    Swedish Institute of Computer Science, Kista, Sweden.
    Mode tracking using multiple data streams2018In: Information Fusion, ISSN 1566-2535, E-ISSN 1872-6305, Vol. 43, p. 33-46Article in journal (Refereed)
    Abstract [en]

    Most existing work in information fusion focuses on combining information with well-defined meaning towards a concrete, pre-specified goal. In contradistinction, we instead aim for autonomous discovery of high-level knowledge from ubiquitous data streams. This paper introduces a method for recognition and tracking of hidden conceptual modes, which are essential to fully understand the operation of complex environments. We consider a scenario of analyzing usage of a fleet of city buses, where the objective is to automatically discover and track modes such as highway route, heavy traffic, or aggressive driver, based on available on-board signals. The method we propose is based on aggregating the data over time, since the high-level modes are only apparent in the longer perspective. We search through different features and subsets of the data, and identify those that lead to good clusterings, interpreting those clusters as initial, rough models of the prospective modes. We utilize Bayesian tracking in order to continuously improve the parameters of those models, based on the new data, while at the same time following how the modes evolve over time. Experiments with artificial data of varying degrees of complexity, as well as on real-world datasets, prove the effectiveness of the proposed method in accurately discovering the modes and in identifying which one best explains the current observations from multiple data streams. © 2017 Elsevier B.V. All rights reserved.

  • 280.
    Bouguelia, Mohamed-Rafik
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Payberah, Amir H.
    Swedish Institute of Computer Science, Stockholm, Sweden.
    An adaptive algorithm for anomaly and novelty detection in evolving data streams2018In: Data mining and knowledge discovery, ISSN 1384-5810, E-ISSN 1573-756X, Vol. 32, no 6, p. 1597-1633Article in journal (Refereed)
    Abstract [en]

    In the era of big data, considerable research focus is being put on designing efficient algorithms capable of learning and extracting high-level knowledge from ubiquitous data streams in an online fashion. While, most existing algorithms assume that data samples are drawn from a stationary distribution, several complex environments deal with data streams that are subject to change over time. Taking this aspect into consideration is an important step towards building truly aware and intelligent systems. In this paper, we propose GNG-A, an adaptive method for incremental unsupervised learning from evolving data streams experiencing various types of change. The proposed method maintains a continuously updated network (graph) of neurons by extending the Growing Neural Gas algorithm with three complementary mechanisms, allowing it to closely track both gradual and sudden changes in the data distribution. First, an adaptation mechanism handles local changes where the distribution is only non-stationary in some regions of the feature space. Second, an adaptive forgetting mechanism identifies and removes neurons that become irrelevant due to the evolving nature of the stream. Finally, a probabilistic evolution mechanism creates new neurons when there is a need to represent data in new regions of the feature space. The proposed method is demonstrated for anomaly and novelty detection in non-stationary environments. Results show that the method handles different data distributions and efficiently reacts to various types of change. © 2018 The Author(s)

  • 281.
    Bouguelia, Mohamed-Rafik
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Santosh, K. C.
    The University of South Dakota, Vermillion, South Dakota, USA.
    Verikas, Antanas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Agreeing to disagree: active learning with noisy labels without crowdsourcing2018In: International Journal of Machine Learning and Cybernetics, ISSN 1868-8071, E-ISSN 1868-808X, Vol. 9, no 8, p. 1307-1319Article in journal (Refereed)
    Abstract [en]

    We propose a new active learning method for classification, which handles label noise without relying on multiple oracles (i.e., crowdsourcing). We propose a strategy that selects (for labeling) instances with a high influence on the learned model. An instance x is said to have a high influence on the model h, if training h on x (with label y = h(x)) would result in a model that greatly disagrees with h on labeling other instances. Then, we propose another strategy that selects (for labeling) instances that are highly influenced by changes in the learned model. An instance x is said to be highly influenced, if training h with a set of instances would result in a committee of models that agree on a common label for x but disagree with h(x). We compare the two strategies and we show, on different publicly available datasets, that selecting instances according to the first strategy while eliminating noisy labels according to the second strategy, greatly improves the accuracy compared to several benchmarking methods, even when a significant amount of instances are mislabeled. © Springer-Verlag Berlin Heidelberg 2017

  • 282.
    Bouguelia, Mohamed-Rafik
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Pashami, Sepideh
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Multi-Task Representation Learning2017In: 30th Annual Workshop ofthe Swedish Artificial Intelligence Society SAIS 2017: May 15–16, 2017, Karlskrona, Sweden / [ed] Niklas Lavesson, Linköping: Linköping University Electronic Press, 2017, p. 53-59Conference paper (Refereed)
    Abstract [en]

    The majority of existing machine learning algorithms assume that training examples are already represented with sufficiently good features, in practice ones that are designed manually. This traditional way of preprocessing the data is not only tedious and time consuming, but also not sufficient to capture all the different aspects of the available information. With big data phenomenon, this issue is only going to grow, as the data is rarely collected and analyzed with a specific purpose in mind, and more often re-used for solving different problems. Moreover, the expert knowledge about the problem which allows them to come up with good representations does not necessarily generalize to other tasks. Therefore, much focus has been put on designing methods that can automatically learn features or representations of the data instead of learning from handcrafted features. However, a lot of this work used ad hoc methods and the theoretical understanding in this area is lacking.

  • 283.
    Bouguerra, Abdelbaki
    et al.
    Centre for Applied Autonomous Sensor Systems (AASS), Örebro University, Sweden.
    Andreasson, Henrik
    Centre for Applied Autonomous Sensor Systems (AASS), Örebro University, Sweden.
    Lilienthal, Achim J.
    Centre for Applied Autonomous Sensor Systems (AASS), Örebro University, Sweden.
    Åstrand, Björn
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    An autonomous robotic system for load transportation2009In: IEEE Conference on Emerging Technologies & Factory Automation, 2009. ETFA 2009, Piscataway, N.J.: IEEE Press, 2009, p. 1-4Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of an autonomous robotic system for material handling. The system is being developed by extending the functionalities of traditional AGVs to be able to operate reliably and safely in highly dynamic environments. Traditionally, the reliable functioning of AGVs relies on the availability of adequate infrastructure to support navigation. In the target environments of our system, such infrastructure is difficult to setup in an efficient way. Additionally, the location of objects to handle are unknown, which requires runtime object detection and tracking. Another requirement to be fulfilled by the system is the ability to generate trajectories dynamically, which is uncommon in industrial AGV systems. ©2009 IEEE.

  • 284.
    Bouguerra, Abdelbaki
    et al.
    Centre for Applied Autonomous Sensor Systems (AASS), Örebro University.
    Andreasson, Henrik
    Centre for Applied Autonomous Sensor Systems (AASS), Örebro University.
    Lilienthal, Achim J
    Centre for Applied Autonomous Sensor Systems (AASS), Örebro University.
    Åstrand, Björn
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    MALTA: A System of Multiple Autonomous Trucks for Load Transportation2009In: Proceedings of the 4th European Conference on Mobile Robots: ECMR’09, September 23 – 25, 2009 Mlini/Dubrovnik, Croatia / [ed] Ivan Petrovi´c Achim J. Lilienthal, Zagreb: KoREMA , 2009, p. 91-96Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of an autonomous robotic material handling system. The goal of the system is to extend the functionalities of traditional AGVs to operate in highly dynamic environments. Traditionally, the reliable functioning of AGVs relies on the availability of adequate infrastructure to support navigation. In the target environments of our system, such infrastructure is difficult to setup in an efficient way. Additionally, the location of objects to handle are unknown, which requires that the system be able to detect and track object positions at runtime. Another requirement of the system is to be able to generate trajectories dynamically, which is uncommon in industrial AGV systems.

  • 285.
    Brauner, Paul
    et al.
    Rice University, Houston, United States.
    Taha, Walid
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Globally Parallel, Locally Sequential: A Preliminary Proposal for Acumen Objects2010In: POOSC'10, Proceedings of the 9th Workshop on Parallel/High-Performance Object-Oriented Scientific Computing, New York, NY: ACM Press, 2010Conference paper (Refereed)
    Abstract [en]

    An important and resource-intensive class of computation codes consists of simulators for physical systems. Today, most simulation codes are written in general-purpose imperative languages such as C or FORTRAN. Unfortunately, such languages encourage the programmer to focus her attention on details of how the computation is performed, rather than on the system being modeled.

    This paper reports the design and implementation of a novel notion of an object for a physical modeling language called Acumen. A key idea underlying the language's design is encouraging a programming style that enables a "globally parallel, locally imperative" view of the world. The language is also being designed to preserve deterministic execution even when the underlying computation is performed on a highly parallel platform. Our main observation with the initial study is that extensive and continual experimental evaluation is crucial for keeping the language design process informed about bottlenecks for parallel execution.

  • 286.
    Brorsson, Sofia
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Gelzinis, Adas
    Kaunas University of Technology, Kaunas, Lithuania.
    Tonkonogi, Michail
    Dalarna University, Falun, Sweden.
    Verikas, Antanas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Differences in the muscle activities in the forearm muscles in healthy men and women2012In: Proceedings of the XIXth Congress of the International Society of Electrophysiology & Kinesiology / [ed] Kylie Tucker et al., Brisbane, Australia, 2012, p. 437-437Conference paper (Refereed)
    Abstract [en]

    Balance between flexor and extensor muscle activity is essential for optimal function. This has been demonstrated previously for the lower extremity, trunk and shoulder function, but information on the relationship in hand function is lacking. AIM: Was to evaluate whether there are qualitative differences in finger extension force(fef), grip force, force duration, force balance and the muscle activities in the forearm flexor and extensor muscles in healthy men and women in different ages. 

  • 287.
    Bruneau, Julien
    et al.
    INRIA, Bordeaux, France.
    Consel, Charles
    INRIA, Bordeaux, France.
    O’Malley, Marcia K.
    Rice University, Houston, TX, United States.
    Taha, Walid
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Rice University, Houston, TX, United States.
    Hannourah, Wail Masry
    HVAC Consultant, Cairo, Egypt.
    Preliminary results in virtual testing for smart buildings2012In: Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, ISSN 1867-8211, E-ISSN 1867-822X, Vol. 73, p. 347-349Article in journal (Refereed)
    Abstract [en]

    Smart buildings promise to revolutionize the way we live. Applications ranging from climate control to fire management can have significant impact on the quality and cost of these services. However, a smart building and any technology with direct effect on the safety of its occupants must undergo extensive testing. Virtual testing by means of computer simulation can significantly reduce the cost of testing and, as a result, accelerate the development of novel applications. Unfortunately, building physically-accurate simulation codes can be labor intensive. To address this problem, we propose a framework for rapid, physically-accurate virtual testing of smart building systems. The proposed framework supports analytical modeling and simulation of both a discrete distributed system as well as the physical environment that hosts it. © 2012 Springer-Verlag Berlin Heidelberg.

  • 288.
    Bruneau, Julien
    et al.
    INRIA Bordeaux Sud-Ouest Talence, Talence, France.
    Consel, Charles
    INRIA Bordeaux Sud-Ouest Talence, Talence, France.
    O’Malley, Marcia
    Rice University Houston, Houston, USA.
    Taha, Walid
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Hannourah, Wail Masry
    HVAC Consultant Cairo, Cairo, Egypt.
    Virtual Testing for Smart Buildings2012In: 2012 Eighth International Conference on Intelligent Environments / [ed] Randall Bilof, Piscataway, N.J.: IEEE Press, 2012, p. 282-289, article id 6258534Conference paper (Refereed)
    Abstract [en]

    Smart buildings promise to revolutionize the way we live. Applications ranging from climate control to fire management can have significant impact on the quality and cost of these services. However, smart buildings and any technology with direct effect on human safety and life mustundergo extensive testing. Virtual testing by means of computer simulation can significantly reduce the cost of testing and, as a result, accelerate the development of novel applications. Unfortunately, building physically-accurate simulation codes can be labor intensive.To address this problem, we propose a framework for rapid, physically-accurate virtual testing. The proposed framework supports analytical modeling of both a discrete distributed system as well as the physical environment that hosts it. The discrete models supported are accurate enough to allow the automatic generation of a dedicated programming framework that will help the developer in the implementation of these systems. The physical environment models supported are equational specifications that are accurate enough to produce running simulation codes. Combined, these two frameworks enable simulating both active systems and physical environments. These simulations can be used to monitor the behavior and gather statistics about the performance of an application in the context of precise virtual experiments. To illustrate the approach, we present models of Heating, Ventilating and Air-Conditioning (HVAC) systems. Using these models, we construct virtual experiments that illustrate how the approach can be used to optimize energy and cost of climate control for a building. © 2012 IEEE.

  • 289.
    Brunnegård, Oliver
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Wikestad, Daniel
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Visual SLAM using sparse maps based on feature points2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Visual Simultaneous Localisation And Mapping is a useful tool forcreating 3D environments with feature points. These visual systemscould be very valuable in autonomous vehicles to improve the localisation.Cameras being a fairly cheap sensor with the capabilityto gather a large amount of data. More efficient algorithms are stillneeded to better interpret the most valuable information. This paperanalyses how much a feature based map can be reduced without losingsignificant accuracy during localising.

    Semantic segmentation created by a deep neural network is used toclassify the features used to create the map, the map is reduced by removingcertain classes. The results show that feature based maps cansignificantly be reduced without losing accuracy. The use of classesresulted in promising results, large amounts of feature were removedbut the system could still localise accurately. Removing some classesgave the same results or even better in certain weather conditionscompared to localisation with a full-scale map.

  • 290.
    Bukina, Elena
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Efficient Numerical Solution of PIDEs in Option Pricing2011Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
  • 291.
    Burnos, Sergey
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Ngow, ChaSing
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE). Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    SVI estimation of the implied volatility by Kalman filter.2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    To understand and model the dynamics of the implied volatility smile is essential for trading, pricing and risk management portfolio. We suggest a  linear Kalman filter for updating of the Stochastic Volatility Inspired (SVI) model of the volatility. From a risk management perspective we generate the 1-day ahead forecast of profit and loss (P\&L) of option portfolios. We compare the estimation of the implied volatility using the SVI model with the cubic polynomial model. We find that the SVI Kalman filter has outperformed the  others.

  • 292.
    Bygstad, B.
    et al.
    Department of Informatics, University of Oslo, Gaustadalléen 23 B, Oslo, Norway.
    Øvrelid, E.
    Department of Informatics, University of Oslo, Gaustadalléen 23 B, Oslo, Norway.
    Lie, T.
    Østfold Hospital, Kalnesveien 300, Grålum, 1714, Norway.
    Bergquist, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Developing and Organizing an Analytics Capability for Patient Flow in a General Hospital2019In: Information Systems Frontiers, ISSN 1387-3326, E-ISSN 1572-9419Article in journal (Refereed)
    Abstract [en]

    Much of the information produced in hospitals is clinical, and stored for the purposes of documentation. In practice, most of it is never used. The potential of analytics is to reuse this information for other purposes. This is easier said than done, because of technical, semantic, legal and organizational hindrances. In particular, hospitals are not organized to leverage the value of big data. In this study we ask, how can we conceptualize analytics as an integrated part of hospital processes? And, how can we develop and organize an analytics capability in a large hospital? Our empirical evidence is a longitudinal study in a high-tech hospital in Norway, where we followed the development of an analytics capability, and assessed the organizational benefits. We offer two findings. First, we show how the analytics process interacts with the hospital logistics processes in a sense- and respond cycle. Second, we demonstrate how analytics capability is built on the institutionalized network of technology, an analytics team and the administrative and clinical decision makers. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

  • 293.
    Bygstad, Bendik
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab). University of Oslo, Oslo, Norway.
    Bergquist, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Horizontal Affordances for Patient Centred Care in Hospitals2018In: Proceedings of the 51st Hawaii International Conference on System Sciences, 2018, p. 3170-3179Conference paper (Refereed)
    Abstract [en]

    While it is generally accepted that patient centred care should be the guiding principle for the delivery of health services, it is not yet clear how this should be digitalised. What is clear, however, is that the current IT solutions are not satisfactory. In this research, we suggest the affordance construct as an analytical lens to understand how technological artefacts and human agency can generate action possibilities to support horizontal process innovation by asking: (i) which affordances enable digitalisation of patient centred healthcare, and (ii) how can these identified affordances be leveraged to innovate patient centred digital hospitals.

    Our empirical evidence is a comparative study of two hospitals in Sweden and Norway. Our theoretical contribution is the identification of six horizontal affordances for patient centred care. The practical contribution is that horizontal affordances emerge through configurations of human actors and lightweight IT solutions, loosely coupled to heavy weight systems.

  • 294.
    Byttner, Stefan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Chalmers University of Technology, Göteborg, Sweden.
    Algorithms for ion current based sensing of combustion variability and pressure peak position2003Licentiate thesis, comprehensive summary (Other academic)
  • 295.
    Byttner, Stefan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Real-time control of an SI engine using ion current based algorithms2005Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Reducing emissions and improving fuel efficiency in automobiles are today important issues. New sensor techniques are developed to extract detailed combustion information to enable closed loop engine control. This thesis is about a virtual sensor; measuring an ion current inside the cylinder by using the already existing spark plug, followed by signal processing for estimation of combustion parameters. First, the thesis aims to show that the ion current signal can be used for closed loop control of Exhaust Gas Recirculation (EGR). Use of EGR is very common in modern automobiles because of the potential reduction of NOx emissions and fuel consumption, but using too much EGR can have the reverse effect (e.g. increased fuel consumption and driveability problems). Algorithms for estimating combustion variability are proposed and a closed loop scheme for controlling an EGR valve is demonstrated for driving on the highway in a SAAB 9000. Estimation of the pressure peak position is treated for closed loop control of ignition timing. Such estimation can be performed with the ion current but may not work if a fuel additive is used. Different methods are compared and it is shown that using a fuel additive may even improve the estimation accuracy of the pressure peak position with about 25%. An algorithm is also proposed to estimate the pressure peak position even in presence of EGR. Strategies for transient control of the air-fuel ratio are also compared. Air-fuel ratio control is important because even small deviations from the stoichiometric value can result in significantly increased emissions. It is found that a neural network based controller had the best performance with approximately 23% lower RMS error than the adapted standard control module.

  • 296.
    Byttner, Stefan
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Holmberg, Ulf
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Closed-loop control of EGR using ion currents2008In: Proceedings of the 27th IASTED International Conference on Modelling, Identification, and Control, MIC / [ed] L. Bruzzone, Anaheim: ACTA Press, 2008, p. 7-Conference paper (Refereed)
    Abstract [en]

    Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition.

  • 297.
    Byttner, Stefan
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Holmberg, Ulf
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Ion Current Based Control of Combustion Variability2003Conference paper (Other academic)
  • 298.
    Byttner, Stefan
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Holmberg, Ulf
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Wickström, Nicholas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    An ion current algorithm for fast determination of high combustion variability2004Conference paper (Refereed)
    Abstract [en]

    It is desirable for an engine control system to maintain a stable combustion. A high combustion variability (typically measured by the relative variations in produced work, COV(IMEP)) can indicate the use of too much EGR or a too lean air-fuel mixture, which results in less engine efficiency(in terms of fuel and emissions) and reduced driveability. The coefficient of variation (COV) of the ion current integral has previously been shown in several papers to be correlated to the coefficient of variation of IMEP for various disturbances (e.g. AFR, EGR and fuel timing). This paper presents a cycle-to-cycle ion current based method of estimating the approximate category of IMEP (either normal burn, slow burn, partial burn or misfire) for the case of lean air-fuel ratio. The rate of appearance of the partial burn and misfire categories is then shown to be well correlated with the onset of high combustion variability(high COV(IMEP)). It is demonstrated that the detection of these categories can result in faster determination(prediction) of high variability compared to only using the COV(Ion integral). Copyright © 2004 SAE International.

  • 299.
    Byttner, Stefan
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Holmberg, Ulf
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Wickström, Nicholas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Using Multiple Cylinder Ion Measurements for Improved Estimation of Combustion Variability2005In: Proceedings of the SAE 2005 World Congress & Exhibition, Warrendale, PA: SAE Inc. , 2005Conference paper (Refereed)
    Abstract [en]

    Estimation of combustion variability can be performed by using ion currents measured at the spark plug. A scheme is here proposed that exploits the potential of using measurements from multiple cylinders to improve the estimation accuracy of combustion variability (measured by the coefficient of variation of IMEP). This is realised by dividing combustion variability into categories and having one classifier running for each cylinder with the ion current as input signal. The final estimate of combustion variability is then formed by a majority vote among the classifiers. This scheme is shown to improve estimation accuracy by up to 15% on measurements taken from highway driving in a production vehicle.

  • 300.
    Byttner, Stefan
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Prytz, Rune
    Volvo Group Trucks Technology, Gothenburg, Sweden.
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    A field test with self-organized modeling for knowledge discovery in a fleet of city buses2013In: 2013 IEEE International Conference on Mechatronics and Automation (ICMA 2013) / [ed] Shuxiang Guo, Piscataway, NJ: IEEE Press, 2013, p. 896-901, article id 6618034Conference paper (Refereed)
    Abstract [en]

    Fleets of commercial vehicles represent an excellent real life setting for ubiquitous knowledge discovery. There are many electronic control units onboard a modern bus or truck, with hundreds of signals being transmitted between them on the controller area network. The growing complexity of the vehicles has lead to a significant desire to have systems for fault detection, remote diagnostics and maintenance prediction. This paper aims to show that it is possible to discover useful diagnostic knowledge by a self-organized algorithm in the scenario of a fleet of city buses. The approach is demonstrated as a process consisting of two parts; Unsupervised modeling (where interesting features are discovered) and Guided search (where the previously found features are coupled to additional information sources). The modeling part searches for simple linear models in a group of vehicles, where interesting features are selected based on both non-randomness in relations and variability in the group. It is shown in an eight months long data collection study that this approach was able to discover features related to broken wheelspeed sensors. Strikingly, deviations in these features (for the vehicles with broken sensors) can be observed up to several months before a breakdown occur. This potentially allows for sufficient time to schedule the vehicle for maintenance and prepare the workshop with relevant components. © 2013 IEEE.

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