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  • 251.
    Bordag, Ljudmila A.
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Chmakova, A. Y.
    Fakultät Mathematik, Naturwissenschaften und Informatik, Brandenburgische Technische Universität Cottbus, Cottbus, Germany.
    Explicit solutions for a nonlinear model of financial derivatives2007Inngår i: International Journal of Theoretical and Applied Finance, ISSN 0219-0249, Vol. 10, nr 1, s. 1-21Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 252.
    Bordag, Ljudmila A.
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Frey, Rüdiger
    Leipzig University, Department of Mathematics.
    Pricing options in illiquid markets: symmetry reductions and exact solutions2008Inngår i: Nonlinear Models in Mathematical Finance: New Research Trends in Option Pricing / [ed] Matthias Ehrhardt, New York: Nova Science Publishers, Inc., 2008, s. 103-130Kapittel i bok, del av antologi (Annet vitenskapelig)
    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.

  • 253.
    Bordag, Ljudmila A.
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Matveev, Sergey K.
    St. Petersburger State University.
    Berechnungen der Gleichgewichtslage der Welle unterpräzisierten geometrischen Voraussetzungen der Druckfluidströmung in LHS 7502009Rapport (Annet vitenskapelig)
  • 254.
    Bordag, Ljudmila A.
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Matveev, Sergey K.
    St. Petersburg State University.
    Erste  Berechnungen der Druckfluidströmung2008Rapport (Annet vitenskapelig)
  • 255.
    Bordag, Ljudmila A.
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Matveev, Sergey K.
    St. Petersburg State University.
    Präzisierte Berechnungender Druckfluidströmung in LHS 7502008Rapport (Annet vitenskapelig)
  • 256.
    Bordag, Ljudmila A.
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Mikaelyan, Anna
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Models of self-financing hedging strategies in illiquid markets: Symmetry reductions and exact solutions2011Inngår i: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, Vol. 96, nr 1-3, s. 191-207Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 257.
    Bordag, Michael
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Interaction of a charge with a thin plasma sheet2007Inngår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 76, nr 6, s. 065011-Artikkel i tidsskrift (Fagfellevurdert)
    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).

  • 258.
    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
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (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 forces2006Inngår i: Proceedings of the 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Piscataway, United States: IEEE Press, 2006, s. 620-622, artikkel-id 4135031Konferansepaper (Fagfellevurdert)
    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.

  • 259.
    Bordag, Michael
    et al.
    Univ Leipzig, Vor Hospitaltore 1, D-04103 Leipzig, Germany..
    Nikolaev, Vladimir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Analytic corrections to the electromagnetic casimir interaction between a sphere and a plate at shortdistances2010Inngår i: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 25, nr 11, s. 2171-2176Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For the vacuum interaction of a sphere 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 In epsilon and e(ln epsilon)(2). We compare this result with the available findings of numerical and experimental approaches.

  • 260.
    Bordag, Michael
    et al.
    Leipzig University, Vor Dem Hospitaltore 1, D-04103 Leipzig, Germany.
    Nikolaev, Vladimir
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Analytic corrections to the electromagnetic casimir interaction between a sphere and a plate at shortdistances2010Inngår i: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 25, nr 11, s. 2171-2176Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 261.
    Bordag, Michael
    et al.
    Leipzig University, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany.
    Nikolaev, Vladimir
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Beyond proximity force approximation in the casimir effect2009Inngår i: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 24, nr 8-9, s. 1743-1747Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 262.
    Bordag, Michael
    et al.
    Institute for Theoretical Physics, Leipzig University, Leipzig, Germany.
    Nikolaev, Vladimir
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Casimir force for a sphere in front of a plane beyond proximity force approximation2008Inngår i: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 41, nr 16, s. 164002-Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 263.
    Bordag, Michael
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Nikolaev, Vladimir
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (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 geometry2010Inngår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 81, nr 6, s. Article number 065011-Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 264.
    Bordag, Michael
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Nikolaev, Vladimir
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    The vacuum energy for two cylinders with one increasing in size2009Inngår i: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 42, nr 41, s. 415203-Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 265.
    Bordag, Michael
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (CAMP).
    Ribayrol, Aline
    Lund University.
    Conache, Gabriela
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (CAMP).
    Fröberg, Linus E.
    Lund University.
    Gray, Struan
    Lund University.
    Samuelson, Lars
    Lund University.
    Montelius, Lars
    Lund University.
    Pettersson, Håkan
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (CAMP).
    Shear stress measurements on InAs nanowires by AFM manipulation2007Inngår i: Small, ISSN 1613-6810, Vol. 3, nr 8, s. 1398-1401Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 266.
    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
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (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 Conditions2011Inngår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 11, nr 9, s. 3935-3940Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 267.
    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
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (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 Conditions2011Konferansepaper (Fagfellevurdert)
  • 268.
    Bosshard, Pascal Fabian
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Investigation of Trajectory Optimization for Multiple Car-Like Vehicles2015Rapport (Annet vitenskapelig)
  • 269.
    Bouguelia, Mohamed-Rafik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Gonzalez, Ramon
    Robotic Mobility Group, Massachusetts Institute of Technology, Cambridge, USA.
    Iagnemma, Karl
    Robotic Mobility Group, Massachusetts Institute of Technology, Cambridge, USA.
    Byttner, Stefan
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Unsupervised classification of slip events for planetary exploration rovers2017Inngår i: Journal of terramechanics, ISSN 0022-4898, E-ISSN 1879-1204, Vol. 73, s. 95-106Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 270.
    Bouguelia, Mohamed-Rafik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Karlsson, Alexander
    University of Skövde, Skövde, Sweden.
    Pashami, Sepideh
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Holst, Anders
    Swedish Institute of Computer Science, Kista, Sweden.
    Mode tracking using multiple data streams2018Inngår i: Information Fusion, ISSN 1566-2535, E-ISSN 1872-6305, Vol. 43, s. 33-46Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 271.
    Bouguelia, Mohamed-Rafik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Payberah, Amir H.
    Swedish Institute of Computer Science, Stockholm, Sweden.
    An adaptive algorithm for anomaly and novelty detection in evolving data streams2018Inngår i: Data mining and knowledge discovery, ISSN 1384-5810, E-ISSN 1573-756X, Vol. 32, nr 6, s. 1597-1633Artikkel i tidsskrift (Fagfellevurdert)
    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)

  • 272.
    Bouguelia, Mohamed-Rafik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Santosh, K. C.
    The University of South Dakota, Vermillion, South Dakota, USA.
    Verikas, Antanas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Agreeing to disagree: active learning with noisy labels without crowdsourcing2018Inngår i: International Journal of Machine Learning and Cybernetics, ISSN 1868-8071, E-ISSN 1868-808X, Vol. 9, nr 8, s. 1307-1319Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 273.
    Bouguelia, Mohamed-Rafik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Pashami, Sepideh
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Multi-Task Representation Learning2017Inngår i: 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, s. 53-59Konferansepaper (Fagfellevurdert)
    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.

  • 274.
    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
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    An autonomous robotic system for load transportation2009Inngår i: IEEE Conference on Emerging Technologies & Factory Automation, 2009. ETFA 2009, Piscataway, N.J.: IEEE Press, 2009, s. 1-4Konferansepaper (Fagfellevurdert)
    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.

  • 275.
    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
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    MALTA: A System of Multiple Autonomous Trucks for Load Transportation2009Inngår i: 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, s. 91-96Konferansepaper (Fagfellevurdert)
    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.

  • 276.
    Brauner, Paul
    et al.
    Rice University, Houston, United States.
    Taha, Walid
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Globally Parallel, Locally Sequential: A Preliminary Proposal for Acumen Objects2010Inngår i: POOSC'10, Proceedings of the 9th Workshop on Parallel/High-Performance Object-Oriented Scientific Computing, New York, NY: ACM Press, 2010Konferansepaper (Fagfellevurdert)
    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.

  • 277.
    Brorsson, Sofia
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Gelzinis, Adas
    Kaunas University of Technology, Kaunas, Lithuania.
    Tonkonogi, Michail
    Dalarna University, Falun, Sweden.
    Verikas, Antanas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Differences in the muscle activities in the forearm muscles in healthy men and women2012Inngår i: Proceedings of the XIXth Congress of the International Society of Electrophysiology & Kinesiology / [ed] Kylie Tucker et al., Brisbane, Australia, 2012, s. 437-437Konferansepaper (Fagfellevurdert)
    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. 

  • 278.
    Bruneau, Julien
    et al.
    INRIA, Bordeaux, France.
    Consel, Charles
    INRIA, Bordeaux, France.
    O’Malley, Marcia K.
    Rice University, Houston, TX, United States.
    Taha, Walid
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Rice University, Houston, TX, United States.
    Hannourah, Wail Masry
    HVAC Consultant, Cairo, Egypt.
    Preliminary results in virtual testing for smart buildings2012Inngår i: Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, ISSN 1867-8211, E-ISSN 1867-822X, Vol. 73, s. 347-349Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 279.
    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
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Hannourah, Wail Masry
    HVAC Consultant Cairo, Cairo, Egypt.
    Virtual Testing for Smart Buildings2012Inngår i: 2012 Eighth International Conference on Intelligent Environments / [ed] Randall Bilof, Piscataway, N.J.: IEEE Press, 2012, s. 282-289, artikkel-id 6258534Konferansepaper (Fagfellevurdert)
    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.

  • 280.
    Brunnegård, Oliver
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Wikestad, Daniel
    Högskolan i Halmstad, Akademin för informationsteknologi, 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 poäng / 30 hpOppgave
    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.

  • 281.
    Bukina, Elena
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Efficient Numerical Solution of PIDEs in Option Pricing2011Independent thesis Advanced level (degree of Master (One Year)), 15 poäng / 22,5 hpOppgave
  • 282.
    Burnos, Sergey
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE). Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Ngow, ChaSing
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE). Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    SVI estimation of the implied volatility by Kalman filter.2010Independent thesis Advanced level (degree of Master (One Year)), 15 poäng / 22,5 hpOppgave
    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.

  • 283.
    Bygstad, Bendik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Människa och Informationsteknologi (MI-lab). University of Oslo, Oslo, Norway.
    Bergquist, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Människa och Informationsteknologi (MI-lab).
    Horizontal Affordances for Patient Centred Care in Hospitals2018Inngår i: Proceedings of the 51st Hawaii International Conference on System Sciences, 2018, s. 3170-3179Konferansepaper (Fagfellevurdert)
    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.

  • 284.
    Byttner, Stefan
    Högskolan i Halmstad, Akademin för informationsteknologi, 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 position2003Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 285.
    Byttner, Stefan
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Real-time control of an SI engine using ion current based algorithms2005Doktoravhandling, monografi (Annet vitenskapelig)
    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.

  • 286.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Holmberg, Ulf
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Closed-loop control of EGR using ion currents2008Inngår i: Proceedings of the 27th IASTED International Conference on Modelling, Identification, and Control, MIC / [ed] L. Bruzzone, Anaheim: ACTA Press, 2008, s. 7-Konferansepaper (Fagfellevurdert)
    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.

  • 287.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Holmberg, Ulf
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Ion Current Based Control of Combustion Variability2003Konferansepaper (Annet vitenskapelig)
  • 288.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Holmberg, Ulf
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Wickström, Nicholas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    An ion current algorithm for fast determination of high combustion variability2004Konferansepaper (Fagfellevurdert)
    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.

  • 289.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Holmberg, Ulf
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Wickström, Nicholas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Using Multiple Cylinder Ion Measurements for Improved Estimation of Combustion Variability2005Inngår i: Proceedings of the SAE 2005 World Congress & Exhibition, Warrendale, PA: SAE Inc. , 2005Konferansepaper (Fagfellevurdert)
    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.

  • 290.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Prytz, Rune
    Volvo Group Trucks Technology, Gothenburg, Sweden.
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    A field test with self-organized modeling for knowledge discovery in a fleet of city buses2013Inngår i: 2013 IEEE International Conference on Mechatronics and Automation (ICMA 2013) / [ed] Shuxiang Guo, Piscataway, NJ: IEEE Press, 2013, s. 896-901, artikkel-id 6618034Konferansepaper (Fagfellevurdert)
    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.

  • 291.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Svensson, Magnus
    Volvo Technology, SE-405 08 Göteborg, Sweden.
    Consensus self-organized models for fault detection (COSMO)2011Inngår i: Engineering applications of artificial intelligence, ISSN 0952-1976, E-ISSN 1873-6769, Vol. 24, nr 5, s. 833-839Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Methods for equipment monitoring are traditionally constructed from specific sensors and/or knowledge collected prior to implementation on the equipment. A different approach is presented here that builds up knowledge over time by exploratory search among the signals available on the internal field-bus system and comparing the observed signal relationships among a group of equipment that perform similar tasks. The approach is developed for the purpose of increasing vehicle uptime, and is therefore demonstrated in the case of a city bus and a heavy duty truck. However, it also works fine for smaller mechatronic systems like computer hard-drives. The approach builds on an onboard self-organized search for models that capture relations among signal values on the vehicles’ data buses, combined with a limited bandwidth telematics gateway and an off-line server application where the parameters of the self-organized models are compared. The presented approach represents a new look at error detection in commercial mechatronic systems, where the normal behavior of a system is actually found under real operating conditions, rather than the behavior observed in a number of laboratory tests or test-drives prior to production of the system. The approach has potential to be the basis for a self-discovering system for general purpose fault detection and diagnostics.

  • 292.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Laboratoriet för intelligenta system.
    Rögnvaldsson, Thorsteinn
    AASS, Örebro University, 701 82 Örebro, Sweden.
    Svensson, Magnus
    Volvo Technology, SE-405 08 Göteborg, Sweden.
    Finding the odd-one-out in fleets of mechatronic systems using embedded intelligent agents2010Inngår i: Embedded reasoning: intelligence in embedded systems : papers from the AAAI Spring Symposium, Menlo Park, California: AAAI Press, 2010, s. 17-19Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With the introduction of low-cost wireless communication many new applications have been made possible; applications where systems can collaboratively learn and get wiser without human supervision. One potential application is automated monitoring for fault isolation in mobile mechatronic systems such as commercial vehicles. The paper proposes an agent design that is based on uploading software agents to a fleet of mechatronic systems. Each agent searches for interesting state representations of a system and reports them to a central server application. The states from the fleet of systems can then be used to form a consensus from which it can be possible to detect deviations and even locating a fault.

  • 293.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Svensson, Magnus
    Volvo Technology, Göteborg, Sweden.
    Modeling for Vehicle Fleet Remote Diagnostics2007Inngår i: Proceedings of SAE 2007 Commercial Vehicle Engineering Congress, Warrendale, PA: SAE Inc. , 2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Quality and up-time management of vehicles is today receiving much attention from vehicle manufacturers. One of the reasons is that there is a desire to avoiding on-road failures to addressing potential issues during routine maintenance intervals or at times more convenient to the operator. Forthcoming telematic platforms and advanced diagnostic algorithms can enable the possibility to proactively handle problems and minimize stops. The platforms bring the possibility of increasing knowledge of fault characteristics and making diagnostic decisions by using a population of vehicles. However, this requires real-time diagnostic algorithms that process data both onboard and offboard at a central server. The paper presents a self organizing approach for failure and deviation detection on a fleet of vehicles. The approach builds on using parametric models for encoding the characteristical relations between different sensor readings for a vehicle sub-system or component. The models are low-dimensional representations of the operating characteristics of a sub-system or component and are possible to transfer over a limited wireless communication channel. The approach is demonstrated on simulated data of an electronically controlled suspension system for detecting a slow valve and a leaking bellow.

  • 294.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Svensson, Magnus
    Volvo Technology, 405 08 Göteborg, Sweden.
    Self-organized Modeling for Vehicle Fleet Based Fault Detection2008Inngår i: Proceedings of the SAE World Congress & Exhibition, Warrendale, PA: SAE Inc. , 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Operators of fleets of vehicles desire the best possible availability and usage of their vehicles. This means the preference is that maintenance of a vehicle is scheduled with as long intervals as possible. However, it is then important to be able to detect if a component in a specific vehicle is not functioning properly earlier than expected (due to e.g. manufacturing variations). This paper proposes a telematic based fault detection scheme for enabling fault detection for diagnostics by using a population of vehicles. The basic idea is that it is possible to create low-dimensional representations of a sub-system or component in a vehicle, where the representation (or model parameters) of a vehicle can be monitored for changes compared to the model parameters observed in a fleet of vehicles. If a model in a vehicle is found to deviate compared to a group of models from a fleet of vehicles, then the vehicle is judged to need diagnostics for that component (assuming the deviation in the model cannot be attributed to e.g. a different driver behavior). The representation should be low-dimensional so it is possible to have it transferred over a limited wireless communication channel to a communications center where the comparison is made. The algorithm is shown to be able to detect leakage on simulated data from a cooling system, work is currently in progress for detecting other types of faults.

  • 295.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Svensson, Magnus
    Volvo Technology, SE-405 08 Göteborg, Sweden.
    Bitar, George
    Volvo Technology of America, 7825 National Service Rd., Greensboro, NC 27409, United States.
    Chominsky, Wesley
    Volvo Trucks North America, 7900 National Service Rd., Greensboro, NC 27409, United States.
    Networked vehicles for automated fault detection2009Inngår i: 2009 IEEE International Symposium on Circuits and Systems: circuits and systems for human centric smart living technologies, conference program, Taipei International Convention Center, Taipei, Taiwan, May 24-May 27, 2009 / [ed] Guo li Chenggong da xue, Piscataway, N.J.: IEEE Press, 2009, s. 1213-1216Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Creating fault detection software for complex mechatronic systems (e.g. modern vehicles) is costly both in terms of engineer time and hardware resources. With the availability of wireless communication in vehicles, information can be transmitted from vehicles to allow historical or fleet comparisons. New networked applications can be created that, e.g., monitor if the behavior of a certain system in a vehicle deviates compared to the system behavior observed in a fleet. This allows a new approach to fault detection that can help reduce development costs of fault detection software and create vehicle individual service planning. The COSMO (consensus self-organized modeling) methodology described in this paper creates a compact representation of the data observed for a subsystem or component in a vehicle. A representation that can be sent to a server in a backoffice and compared to similar representations for other vehicles. The backoffice server can collect representations from a single vehicle over time or from a fleet of vehicles to define a norm of the vehicle condition. The vehicle condition can then be monitored, looking for deviations from the norm. The method is demonstrated for measurements made on a real truck driven in varied conditions with ten different generated faults. The proposed method is able to detect all cases without prior information on what a fault looks like or which signals to use.

  • 296.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Wickström, Nicholas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Estimation of combustion variability using in-cylinder ionization measurements2001Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper investigates the use of the ionization current to estimate the Coefficient of Variation for the Indicated Mean Effective Pressure, COV(IMEP), which is a common variable for combustion stability in a spark-ignited engine. Stable combustion in this definition implies that the variance of the produced work, measured over a number of consecutive combustion cycles, is small compared to the mean of the produced work. The COV(IMEP) is varied experimentally either by increasing EGR flow or by changing the air-fuel ratio, in both a laboratory setting (engine in dynamometer) and in an on-road setting. The experiments show a positive correlation between COV(Ion integral), the Coefficient of Variation for the integrated Ion Current, and COV(IMEP), when measured under low load on an engine in a dynamometer, but not under high load conditions. On-road experiments show a positive correlation, but only in the EGR and the lean burn case. An approach based on individual cycle classification for real-time estimation of combustion stability is discussed. © Copyright 2001 Society of Automotive Engineers, Inc.

  • 297.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Wickström, Nicholas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Strategies for handling the fuel additive problem in neural network based ion current interpretation2001Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With the introduction of unleaded gasoline, special fuel agents have appeared on the market for lubricating and cleaning the valve seats. These fuel agents often contain alkali metals that have a significant impact on the ion current signal, thus affecting strategies that use the ion current for engine control and diagnosis, e.g., for estimating the location of the pressure peak. This paper introduces a method for making neural network algorithms robust to expected disturbances in the input signal and demonstrates how well this method applies to the case of disturbances to the ion current signal due to fuel additives containing sodium. The performance of the neural estimators is compared to a Gaussian fit algorithm, which they outperform. It is also shown that using a fuel additive significantly improves the estimation of the location of the pressure peak. © 2001 Society of Automotive Engineers, Inc.

  • 298.
    Byttner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligenta system (IS-lab).
    Svensson, Magnus
    Volvo Technology, 405 08 Göteborg, Sweden.
    Vachkov, Gancho
    Reliability-based Information Systems Engineering, Kagawa University, 761-0396 Kagawa, Japan.
    Incremental classification of process data for anomaly detection based on similarity analysis2011Inngår i: EAIS 2011: 2011 IEEE Workshop on Evolving and Adaptive Intelligent Systems : April 11-15, 2011, Paris, France, Piscataway, N.J.: IEEE Press, 2011, s. 108-115Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Performance evaluation and anomaly detection in complex systems are time consuming tasks based on analyzing, similarity analysis and classification of many different data sets from real operations. This paper presents an original computational technology for unsupervised incremental classification of large data sets by using a specially introduced similarity analysis method. First of all the so called compressed data models are obtained from the original large data sets by a newly proposed sequential clustering algorithm. Then the datasets are compared by pairs not directly, but by using their respective compressed data models. The evaluation of the pairs is done by a special similarity analysis method that uses the so called Intelligent Sensors (Agents) and data potentials. Finally a classification decision is generated by using a predefined threshold of similarity. The applicability of the proposed computational scheme for anomaly detection, based on many available large data sets is demonstrated on an example of 18 synthetic data sets. Suggestions for further improvements of the whole computation technology and a better applicability are also discussed in the paper.

  • 299.
    Bååth, Lars
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Maskinteknisk produktframtagning (MTEK), Fotonik och mikrovågsteknik.
    Nilsson, Emil
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Method and device for multidimensional imaging2007Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    PROBLEM TO BE SOLVED: To provide a method and system using transmission of an electromagnetic signal in order to determine the positions of reflection points by detecting the signals reflected at the reflection points in space. ; SOLUTION: The present invention provides a method, antenna, and system for defining the positions of the reflection points using microwave. The electromagnetic signal is generated at a determined frequency, and is transmitted by an antenna unit. The antenna unit comprises a transmitting antenna, and many receiving antennas that are separated at a known interval in the direction perpendicular to the main visual axis and are designed to receive a part of the reflected wave of the transmitted wave. A phase comparing means is connected to the transmitting antenna and receiving antennas, and a control unit connected to the phase comparing means can calculate an angle to the reflection points and calculate the distances to the reflection points. ; COPYRIGHT: (C)2007,JPO&INPIT

  • 300.
    Bååth, Lars
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Maskinteknisk produktframtagning (MTEK), Fotonik och mikrovågsteknik.
    Nilsson, Emil
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Multi-dimensional imaging method and apparatus2007Patent (Annet (populærvitenskap, debatt, mm))
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