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  • 201.
    Bengtsson, Matilda
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Color adjustment of digital images of clothes for truthful rendering2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    E-commerce is a growing market for selling gods and digital images are often used to display the product. However, there is a problem when the color of the object does not match the reality. This can lead to a dissatisfaction of the customer and a return of the product. Returned goods causes a significant loss in revenue for the suppliers. One reason for untruthful rendering of colors in images is due to different temperatures, or colors, of the illumination sources lighting the scene and the object. This effect can be reduced by a method called white balance. In this thesis, an algorithm based on the technique in Hsu et al. was implemented for a more truthful rendering of images of clothes and toys used in e-commerce. The algorithm removes unwanted color casts induced in the image from two different illumination sources. The thesis also marks important details missing in aforementioned paper as well as some drawbacks of the proposed technique, such as high processing time.

  • 202.
    Bengtsson, Ola
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Baerveldt, Albert-Jan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Localization in changing environments - Estimation of a covariance matrix for the IDC algorithm2001In: Proceedings 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems. Expanding the Societal Role of Robotics in the the Next Millennium (Cat. No.01CH37180): Volume 4 of 4, Piscataway, N.J.: IEEE, 2001, p. 1931-1937Conference paper (Refereed)
    Abstract [en]

    Previously we have presented a new scan-matching algorithm, based on the IDC - Iterative Dual Correspondence- algorithm, which showed a good localization performance even in the case of severe changes in the environment. The Problem of the IDC-algorithm is that there is no good way to estimate the covariance matrix of the position estimate, which prohibits an effective fusion with other position estimates from other sensors, e.g by means of the Kalman filter. In this paper we present a new way to estimate the covariance matrix, by estimating the Hessian matrix of the error function that is minimized by the IDC scan-matching algorithm. Simulation results show that the estimated covariance matrix correspond well to the real one.

  • 203.
    Bengtsson, Ola
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Baerveldt, Albert-Jan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Localization in changing environments by matching laser range scans1999In: 1999 Third European Workshop on Advanced Mobile Robots (Eurobot'99).: Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 1999, p. 169-176Conference paper (Refereed)
    Abstract [en]

    We present a novel scan matching algorithm, IDC-S, Iterative Dual Correspondence-Sector, that matches range scans. The algorithm is based on the known Iterative Dual Correspondence, IDC, algorithm which has shown good performance in real environments. The improvement is that IDC-S is able to deal with relatively large changes in the environment. It divides the scan in several sectors, detects and removes those sectors that are changed and matches the scans only using unchanged sectors. IDC-S and other variants of IDC are extensively simulated and evaluated. The simulations show that IDC-S is very robust and can locate in many different kind of environments. We also show that it is possible to effectively combine the existing IDC algorithms with IDC-S, thus obtaining an algorithm that performs very well both in rectilinear as well as nonrectilinear environments, even when changed as much as 65%. © 1999 IEEE.

  • 204.
    Bengtsson, Ola
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Baerveldt, Albert-Jan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Robot localization based on scan-matching - estimating the covariance matrix for the IDC algorithm2003In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 44, no 1, p. 29-40Article in journal (Refereed)
    Abstract [en]

    We have previously presented a new scan-matching algorithm based on the IDC (iterative dual correspondence) algorithm, which showed a good localization performance even in environments with severe changes. The problem of the IDC algorithm is that there is no good way to estimate a covariance matrix of the position estimate, which prohibits an effective fusion with other position estimates of other sensors. This paper presents two new ways to estimate the covariance matrix. The first estimates the covariance matrix from the Hessian matrix of the error function minimized by the scan-matching algorithm. The second one, which is an off-line method, estimates the covariance matrix of a specific scan, from a specific position by simulating and matching scans around the position. Simulation results show that the covariance matrix provided by the off-line method fully corresponds with the real one. Some preliminary tests on real data indicate that the off-line method gives a good quality value of a specific scan position, which is of great value in map building.

  • 205.
    Bentes, João
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Service platform for continuous delivery of assisted living systems2016In: Middleware Doctoral Symposium'16: Proceedings of the Doctoral Symposium of the 17th International Middleware Conference, New York: Association for Computing Machinery (ACM), 2016, article id 6Conference paper (Refereed)
    Abstract [en]

    A smart home has potential to support independent living of elderly people in their preferred living environments. However, smart home systems do not fully address the aims of Ambient assisted living (AAL), mainly due to limited support outside the home. This need of continuous delivery of assistance for elderly people on the go require technology which extends the home into the society. This ongoing work proposes to identify the architectural requirements for a service platform being able to continuously deliver assistive services at home and beyond. © 2016 Copyright held by the owner/author(s). Publication rights licensed to ACM.

  • 206.
    Bentes, João
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Khandelwal, Siddhartha
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Carlsson, Hampus
    Halmstad University, School of Information Technology.
    Kärrman, Marcus
    Halmstad University, School of Information Technology.
    Svensson, Tim
    Halmstad University, School of Information Technology.
    Wickström, Nicholas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Novel System Architecture for Online Gait Analysis2017Conference paper (Refereed)
    Abstract [en]

    Although wearable devices can be used to perform continuous gait analysis in daily life, existing platforms only support short-term analysis in quasi-controlled environments. This paper proposes a novel system architecture that is designed for long-term, online gait analysis in free-living environments. Various aspects related to the feasibility and scalability of the proposed system are presented.

  • 207.
    Beohar, Harsh
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Cuijpers, Pieter
    Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Avoiding Diamonds in Desynchronisation2014In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 91, no PART A, p. 45-69Article in journal (Refereed)
    Abstract [en]

    The design of concurrent systems often assumes synchronous communication between different parts of a system. When system components are physically apart, this assumption becomes inappropriate. Desynchronisation is a technique that aims to implement a synchronous design in an asynchronous manner by placing buffers between the components of the synchronous design. When queues are used as buffers, the so-called 'diamond property' (among others) ensures correct operation of the desynchronised design. However, this property is difficult to establish in practice. In this paper, we give sufficient and necessary conditions under which a concrete synchronous design (i.e., without the unobservable action) is equivalent to an asynchronous design and formally prove that the diamond property is no longer needed for desynchronisation when half-duplex queues are used as a communication buffer. Furthermore, we discuss how the half-duplex condition can be further relaxed when the diamond property can be partially guaranteed. To illustrate how this theory may be applied, we desynchronise the synchronous systems that are synthesised using supervisory control theory. © 2013 Elsevier B.V.

  • 208.
    Beohar, Harsh
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    A Pre-congruence Format for XY-simulation2015In: Fundamentals of Software Engineering: 6th International Conference, FSEN 2015 Tehran, Iran, April 22–24, 2015, Revised Selected Papers / [ed] Mehdi Dastani & Marjan Sirjani, Cham: Springer, 2015, Vol. 9392, p. 215-229Conference paper (Refereed)
    Abstract [en]

    XY-simulation is a generalization of bisimulation that is parameterized with two subsets of actions. XY-simulation is known in the literature under different names such as modal refinement, partial bisimulation, and alternating simulation. In this paper, we propose a precongruence rule format for XY-simulation. The format allows for checking compositionality of XY-simulation for an arbitrary language with structural operational semantics, by performing very simple checks on the syntactic shape of the rules. We apply our format to derive concrete compositionality results for different notions of behavioral pre-order with respect to different process calculi in the literature. © IFIP International Federation for Information Processing 2015

  • 209.
    Beohar, Harsh
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Input-output conformance testing based on featured transition systems2014In: Proceedings of the 29th Annual ACM Symposium on Applied Computing, Association for Computing Machinery (ACM), 2014, p. 1272-1278Conference paper (Refereed)
    Abstract [en]

    We extend the theory of input-output conformance testing to the setting of software product lines. In particular, we allow for input-output featured transition systems to be used as the basis for generating test suites and test cases. We introduce refinement operators both at the level of models and at the level of test suites that allow for projecting them into a specific product configuration (or a product sub-line). We show that the two sorts of refinement are consistent and lead to the same set of test-cases. © Copyright 2014 ACM

  • 210.
    Beohar, Harsh
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Input–output conformance testing for software product lines2016In: The Journal of logical and algebraic methods in programming, ISSN 2352-2208, E-ISSN 2352-2216, Vol. 85, no 6, p. 1131-1153Article in journal (Refereed)
    Abstract [en]

    We extend the theory of input-output conformance (IOCO) testing to accommodate behavioral models of software product lines (SPLs). We present the notions of residual and spinal testing. These notions allow for structuring the test process for SPLs by taking variability into account and extracting separate test suites for common and specific features of an SPL. The introduced notions of residual and spinal test suites allow for focusing on the newly introduced behavior and avoiding unnecessary re-test of the old one. Residual test suites are very conservative in that they require retesting the old behavior that can reach to new behavior. However, spinal test suites more aggressively prune the old tests and only focus on those test sequences that are necessary in reaching the new behavior. We show that residual testing is complete but does not usually lead to much reduction in the test-suite. In contrast, spinal testing is not necessarily complete but does reduce the test-suite. We give sufficient conditions on the implementation to guarantee completeness of spinal testing. Finally, we specify and analyze an example regarding the Ceiling Speed Monitoring Function from the European Train Control System. (C) 2016 The Author(s). Published by Elsevier Inc.

  • 211.
    Beohar, Harsh
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Spinal test suites for software product lines2014In: Proceedings: Ninth Workshop on Model-Based Testing (MBT 2014) / [ed] Alexander K. Petrenko, Holger Schlingloff, Sydney: Open Publishing Association , 2014, Vol. 141, p. 44-55Conference paper (Refereed)
    Abstract [en]

    A major challenge in testing software product lines is efficiency. In particular, testing a product line should take less effort than testing each and every product individually. We address this issue in the context of input-output conformance testing, which is a formal theory of model-based testing. We extend the notion of conformance testing on input-output featured transition systems with the novel concept of spinal test suites. We show how this concept dispenses with retesting the common behavior among different, but similar, products of a software product line. © H. Beohar & M.R. Mousavi.

  • 212.
    Beohar, Harsh
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Varshosaz, Mahsa
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Basic behavioral models for software product lines: Expressiveness and testing pre-orders2016In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 123, p. 42-60Article in journal (Refereed)
    Abstract [en]

    In order to provide a rigorous foundation for Software Product Lines (SPLs), several fundamental approaches have been proposed to their formal behavioral modeling. In this paper, we provide a structured overview of those formalisms based on labeled transition systems and compare their expressiveness in terms of the set of products they can specify. Moreover, we define the notion of tests for each of these formalisms and show that our notions of testing precisely capture product derivation, i.e., all valid products will pass the set of test cases of the product line and each invalid product fails at least one test case of the product line. © 2015 The Authors.

  • 213.
    Berbineau, Marion
    et al.
    IFSTTAR, Villeneuve d’Ascq, France.
    Jonsson, MagnusHalmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).Bonnin, Jean-MarieTelecom Bretagne, Cesson Sévigné, France.Cherkaoui, SoumayaUniversité de Sherbrooke, Canada.Aguado, MarinaUniversity of the Basque Country, Bilbao, Spain.Rico Garcia, CristinaDLR, German Aerospace Center, Oberpfaffenhofen-Wessling, Germany.Ghannoum, HassanSNCF, Paris, France.Mehmood, RashidUniversity of Huddersfield, UK.Vinel, AlexeyTampere University of Technology, Finland.
    Communication Technologies for Vehicles: 5th International Workshop, Nets4Cars/Nets4Trains 2013, Villeneuve d' Ascq, France, May 14-15, 2013, Proceedings2013Conference proceedings (editor) (Refereed)
  • 214.
    Beremark, Mikael
    et al.
    Halmstad University, School of Information Technology.
    Fryland, John
    Halmstad University, School of Information Technology.
    A Comparison of Intrusion Detection Systems in Home Networks2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The security in home networks is a growing concern, not in the least due to the increase in connected devices with the Internet of Things (IoT). Different types of Intrusion Detection Systems (IDS’s) exists with various system requirements. This thesis will research and compare two of these, Bro and Snort IDS in order to determine their functionality in a low resource environment such as a Raspberry Pi. In order to measure functionality and performance, several experiments have been conducted such as penetration testing and thorough installation and configuration experiments.

  • 215.
    Berg, Alexander
    et al.
    Lund University, Lund, Sweden.
    Yazdi, Sadegh
    Technical University of Denmark, Lyngby, Denmark.
    Nowzari, Ali
    Lund University, Lund, Sweden.
    Storm, Kristian
    Lund University, Lund, Sweden.
    Jain, Vishal
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Lund University, Lund, Sweden.
    Vainorius, Neimantas
    Lund University, Lund, Sweden.
    Samuelson, Lars
    Lund University, Lund, Sweden.
    Wagner, Jakob B.
    Technical University of Denmark, Lyngby, Denmark.
    Borgström, Magnus T.
    Lund University, Lund, Sweden.
    Radial Nanowire Light-Emitting Diodes in the (AlxGa1-x)yIn1-yP Material System2016In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 16, no 1, p. 656-662Article in journal (Refereed)
    Abstract [en]

    Nanowires have the potential to play an important role for next-generation light-emitting diodes. In this work, we present a growth scheme for radial nanowire quantum-well structures in the AlGaInP material system using a GaInP nanowire core as a template for radial growth with GaInP as the active layer for emission and AlGaInP as charge carrier barriers. The different layers were analyzed by X-ray diffraction to ensure lattice-matched radial structures. Furthermore, we evaluated the material composition and heterojunction interface sharpness by scanning transmission electron microscopy energy dispersive X-ray spectroscopy. The electro-optical properties were investigated by injection luminescence measurements. The presented results can be a valuable track toward radial nanowire light-emitting diodes in the AlGaInP material system in the red/orange/yellow color spectrum. © 2015 American Chemical Society.

  • 216.
    Berg, Martin
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Smart jewellery: measuring the unknown2016Conference paper (Refereed)
    Abstract [en]

    Self-tracking devices and apps often measure and provide interpretations of personal data in a rather straightforward way, for instance by visualising the speed and distance of a run or the quality of sleep during a night. There is however a growing number of devices that take the data analysis further by providing insights and algorithmic advices about domains of our lives that are otherwise thought of as difficult to grasp. This paper explores two devices of this kind, namely the Moodmetric and the ŌURA which are two recently released smart rings with associated mobile apps that claim to measure emotions and rest, promote happiness and help users to perform better. Whereas several studies have shed light over how users engage with self-tracking apps and devices, little attention has been paid to how these technologies stem from dreams, hopes and imaginaries of designers and developers. This paper approaches self-tracking from a producer perspective in order to frame how users and their everyday lives are imagined by designers and how these assumptions are built into the technologies. Empirically, the paper is based on a content analysis of blog posts, marketing materials and user guides from the ŌURA and Moodmetric companies along with video interviews with company representatives as well as recordings of their public appearances. Engaging with the field of software studies as well as the emerging field of self-tracking studies, this paper aims at providing a basis for further design oriented studies of self-tracking.

  • 217.
    Berg, Martin
    et al.
    Malmö University, Malmö, Sweden.
    Fors, Vaike
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Workshops as Nodes of Knowledge Co-production: Beyond Ideas of Automagical Synergies2017In: Theoretical Scholarship and Applied Practice / [ed] Sarah Pink, Vaike Fors & Tom O'Dell, New York: Berghahn Books, 2017, p. 53-72Chapter in book (Refereed)
  • 218.
    Berg, Martin
    et al.
    Malmö universitet, Malmö, Sverige.
    Fors, VaikeHalmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).Willim, RobertLunds universitet, Lund, Sverige.
    Samverkansformer: Nya vägar för humaniora och samhällsvetenskap2018Collection (editor) (Other academic)
  • 219.
    Berg, Stina
    et al.
    Halmstad University, School of Information Technology.
    Lilja Sjökrans, Elisabet
    Halmstad University, School of Information Technology.
    Load Imbalance Detection for an Induction Motor: - A Comparative Study of Machine Learning Algorithms2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2016 the average industry downtime cost was estimated to $260.000 every hour, and with Swedish industries being an important part of the national economy it would be desirable to reduce the amount of unplanned downtime to a minimum. There are currently many different solutions for system supervision for monitoring system health but none which analyse data with machine learning in an industrial gateway.

     

    The aim for this thesis is to test, compare and evaluate three different algorithms to find a classifier suitable for a gateway environment. The evaluated algorithms were Random Forest, K-Nearest Neighbour and Linear Discriminant Analysis. Load imbalance detection was used as a case study for evaluating these algorithms. The gateway received data from a Modbus ATV32 frequency converter, which measured specific features from an induction motor. The imbalance was created with loads that were attached on a fly-wheel at different angles to simulate different imbalances. The classifiers were compared on their accuracy, memory usage, CPU usage and execution time. The result was evaluated with tables, confusion matrices and AUC- ROC curves.  Although all algorithms performed well LDA was best based on the criteria set.

  • 220. Bergenhem, Carl
    et al.
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    A pipelined fiber-ribbon ring network with heterogeneous real-time support2006In: ARTES - A network for Real-Time research and graduate Education in Sweden 1997-2006 / [ed] Hansson, H., Uppsala: Uppsala university : Department of Information Technology , 2006, p. 23-Conference paper (Refereed)
    Abstract [en]

    The paper presents results of simulations done with the CCR-EDF (Control Channel based Ring network with EDF scheduling) pipelined ring network together with a case study of system area networks for radar signal processing. The topology of the network is a pipelined unidirectional fibre-ribbon ring that supports several simultaneous transmissions in non-overlapping segments. Access to the network is divided into slots. In each slot the node that has the highest priority message is permitted to transmit. This feature of the medium access protocol gives the network the functionality for earliest deadline first scheduling. Different classes of traffic are supported for the user. These are guaranteed logical real-time channels (LRTC), best effort (BE) channels and non real-time (NRT) traffic. The case study used is from an airborne radar signal processing (RSP) application. Results of the simulations indicate that the CCR-EDF network works well with the RSP application studied.

  • 221.
    Bergenhem, Carl
    et al.
    SP - Technical Research Institute of Sweden Department of Electronics, Borås, Sweden.
    Jonsson, Magnus
    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).
    Two Protocols with Heterogeneous Real-Time Services for High-Performance Embedded Networks2012Report (Other academic)
    Abstract [en]

    High-performance embedded networks are found in computer systems that perform applications such as radar signal processing and multimedia rendering. The system can be composed of multiple computer nodes that are interconnected with the network. Properties of the network such as latency and speed affect the performance of the entire system. A node´s access to the network is controlled by a medium access protocol. This protocol decides e.g. real-time properties and services that the network will offer its users, i.e. the nodes. Two such network protocols with heterogeneous real-time services are presented. The protocols offer different communication services and services for parallel and distributed real-time processing. The latter services include barrier synchronisation, global reduction and short message service. A network topology of a unidirectional pipelined optical fibre-ribbon ring is assumed for both presented protocols. In such a network several simultaneous transmissions in non-overlapping segments are possible. Both protocols are aimed for applications that require a high-performance embedded network such as radar signal processing and multimedia. In these applications the system can be organised as multiple interconnected computation nodes that co-operate in parallel to achieve higher performance. The computing performance of the whole system is greatly affected by the choice of network. Computing nodes in a system for radar signal processing should be tightly coupled, i.e., communications cost, such as latency, between nodes should be small. This is possible if a suitable network with an efficient protocol is used. The target applications have heterogeneous real-time requirements for communication in that different classes of data-traffic exist. The traffic can be classified according to its requirements. The proposed protocols partition data-traffic into three classes with distinctly different qualities. These classes are: traffic with hard real-time demands, such as mission critical commands; traffic with soft real-time demands, such as application data (a deadline miss here only leads to decreased performance); and traffic with no real-time constraints at all. The protocols are analysed and performance is tested through simulation with different data-traffic patterns.

  • 222.
    Berger, Christian
    et al.
    University of Gothenburg, Gothenburg, Sweden.
    Mousavi, Mohammad RezaHalmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Cyber Physical Systems. Design, Modeling, and Evaluation: 5th International Workshop, CyPhy 2015, Amsterdam, The Netherlands, October 8, 2015, Proceedings2015Collection (editor) (Refereed)
  • 223.
    Bergman, Lars
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Using multicoloured halftone screens for offset print quality monitoring2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the newspaper printing industry, offset is the dominating printing method and the use of multicolour printing has increased rapidly in newspapers during the last decade. The offset printing process relies on the assumption that an uniform film of ink of right thickness is transferred onto the printing areas. The quality of reproduction of colour images in offset printing is dependent on a number of parameters in a chain of steps and in the end it is the amount and the distribution of ink deposited on the substrate that create the sensation and thus the perceived colours. We identify three control points in the offset printing process and present methods for assessing the printing process quality in two of these points:

    • Methods for determining if the printing plates carry the correct image

    • Methods for determining the amount of ink deposited onto the newsprint

    A new concept of colour impression is introduced as a measure of the amount of ink deposited on the newsprint. Two factors contribute to values of the colour impression, the halftone dot-size and ink density. Colour impression values are determined on gray-bars using a CCD-camera based system. Colour impression values can also be determined in an area containing an arbitrary combination of cyan magenta and yellow inks. The correct amount of ink is known either from a reference print or from prepress information. Thus, the deviation of the amount of ink can be determined that can be used as control value by a press operator or as input to a control system.

    How a closed loop controller can be designed based on the colour impression values is also shown.

    It is demonstrated that the methods developed can be used for off-line print quality monitoring and ink feed control, or preferably in an online system in a newspaper printing press.

  • 224.
    Bergman, Lars
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Verikas, Antanas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Intelligent Monitoring of the Offset Printing Process2004In: Proceedings of the IASTED International Conference on Neural Networks and Computational Intelligence, ACTA Press, 2004, p. 173-178Conference paper (Refereed)
    Abstract [en]

    In this paper, we present a neural networks and image analysis based approach to assessing colour deviations in an offset printing process from direct measurements on halftone multicoloured pictures--there are no measuring areas printed solely to assess the deviations. A committee of neural networks is trained to assess the ink proportions in a small image area. From only one measurement the trained committee is capable of estimating the actual amount of printing inks dispersed on paper in the measuring area. To match the measured image area of the printed picture with the corresponding area of the original image, when comparing the actual ink proportions with the targeted ones, properties of the 2-D Fourier transform are exploited.

  • 225.
    Bergman, Lars
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Verikas, Antanas
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bacauskiene, M.
    Department of Applied Electronics, Kaunas University of Technology.
    Unsupervised colour image segmentation applied to printing quality assessment2005In: Image and Vision Computing, ISSN 0262-8856, E-ISSN 1872-8138, Vol. 23, no 4, p. 417-425Article in journal (Refereed)
    Abstract [en]

    We present an option for colour image segmentation applied to printing quality assessment in offset lithographic printing by measuring an average ink dot size in halftone pictures. The segmentation is accomplished in two stages through classification of image pixels. In the first stage, rough image segmentation is performed. The results of the first segmentation stage are then utilized to collect a balanced training data set for learning refined parameters of the decision rules. The developed software is successfully used in a printing shop to assess the ink dot size on paper and printing plates.

  • 226.
    Bergman, Lars
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Verikas, Antanas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Kindberg, J.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Olsson, J.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Sjögren, B.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Modelling and Control of the Web-Fed Offset Newspaper Printing Press2003In: Proceedings of the Technical Association of the Graphic Arts, TAGA, Technical Association of the Graphic (TAGA) , 2003, p. 27-29Conference paper (Refereed)
    Abstract [en]

    We present an approach to modelling and controlling the web-fed offset printing process. An image processing and artificial neural networks based device is used to measure the printing process output - the observable variables. The observable variables are measured on halftone areas and integrate information about both ink densities and dot sizes. From only one measurement the device is capable of estimating the actual relative amount of each cyan, magenta, yellow, and black ink dispersed on paper in the measuring area. We build and test linear and non-linear printing press models using the measured variables andother parameters characterising the press. The observable variables measured and the press model developed are then further used by a control unit for generating control signals - signals for controlling the ink keys - to compensate for colour deviation. The experimental investigations performed have shown that the non-linear model developed is accurate enough to be used in a control loop for controlling the printing process. The control accuracy - the tracking accuracy of the desired ink level - obtained from the controller was higher than that observed when controlling the press by the operator.

  • 227.
    Bergquist, Magnus
    et al.
    Gothenburg University, Sweden.
    Ihlström Eriksson, Carina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Ljungberg, Jan
    Gothenburg University, Sweden.
    Åkesson, Maria
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Combining Actor Network Theory and Genre Theory to Understand the Evolution of Digital Genres2008In: Proceedings of JAIS Theory Development Workshop, Amsterdam: Sprouts Alliance , 2008, p. 36-Conference paper (Refereed)
    Abstract [en]

    In this paper we argue that a combination of Actor-Network Theory (ANT) and Genre Theory can constitute a theoretical framework for understanding how digital genres evolve. Genre theory states that genres evolve over time through reciprocal interaction between institutionalized practices and individual action; that they develop from actors’ responses to recurrent situations, and are shaped around characteristics as content, form, functionality and purpose. Genres emerge out of practice and at the same time they shape that practice. While genre theory can describe the characteristics of a genre, it cannot handle the process of how a genre is formed and what powers and forces are involved in this shaping process. In order to address this problem, several authors have incorporated structuration theory into genre analysis. However, structuration theory can only catch these constitutional processes of genre in a very broad manner. As a genre is evolving and stabilizing over time in interplay with different actors, it goes beyond what is possible to explain only by means of structuration theory. Instead, ANT could work as a tool to capture the process of how a genre takes form in negotiations with different stakeholders. In this paper we discuss how genre theory and ANT can be combined in a framework for analyzing emerging genres. We apply this theoretical framework on an e-newspaper project that embodies a new genre in the making. We will here show how evolving genre characteristics are developed, formed and stabilized in a negotiation and struggle between the involved actors when they translate their interests in ways that finally are resulting in a new genre.

  • 228.
    Bergquist, Magnus
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Ljungberg, Jan
    University of Gothenburg, Gothenburg, Sweden.
    Remneland, Björn
    University of Gothenburg, Gothenburg, Sweden.
    Rolandsson, Bertil
    University of Gothenburg, Gothenburg, Sweden.
    From e-government to e-governance: social media and public authorities legitimacy work2017In: Proceedings of the 25th European Conference on Information Systems (ECIS), 2017, p. 858-872Conference paper (Refereed)
    Abstract [en]

    Social media increasingly condition how public authorities build legitimacy when engaging with citizens. In this paper we report on a study of the increasing use of and exposure to social media and social networking platforms in two Swedish public authorities, the Social Insurance Agency (SIA) and the police force. Although formally grounded on the same civic principles, the two authorities have significantly different approaches to social media as a way to generate internal and external legitimacy. SIA has mainly implemented an e-government approach to rationalize services to become more efficient and customer oriented, by using social media as one of several media channels. The police force, however, adopted an e-governance approach to build legitimacy through interaction and reflexive discussion between government and citizens as a way to create transparency and nuance citizens’ attitude towards the police force. Building on a two-dimensional public government/governance framework, we reflect on how the two studied authorities’ social media practices shape and are shaped by different governing practices in their legitimacy work.

  • 229.
    Bergvall-Kåreborn, Birgitta
    et al.
    Luleå University of Technology, Luleå, Sweden.
    Ihlström Eriksson, Carina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Melander Wikman, Anita
    Luleå University of Technology, Luleå, Sweden.
    Ståhlbröst, Anna
    Luleå University of Technology, Luleå, Sweden.
    A Model for Reflective Participatory Design - The Role of Participation, Voice and Space2015In: AMCIS 2015 Proceedings, AIS Electronic Library (AISeL) , 2015Conference paper (Refereed)
    Abstract [en]

    This paper aims to contribute to the participatory tradition in health informatics by presenting a model for reflective participatory design emerging from qualitative fieldwork in a participatory project aimed to improve the health and wellbeing of older people in the northern periphery regions of Europe, through new mobile services. The model brings together two established processes in novel ways: systems development and user participation. Within each process three concepts are presented to facilitate discussion and reflection at the concept level, the process level and the integrated process level.

  • 230.
    Bergvall-Kåreborn, Birgitta
    et al.
    Luleå University of Technology, Luleå, Sweden.
    Ihlström Eriksson, Carina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Ståhlbröst, Anna
    Luleå University of Technology, Luleå, Sweden.
    Places and Spaces - Their Influence on Innovation Milieus and Innovation Processes2015In: Proceedings of the 2015 ISPIM Conference in Budapest, June 14-17, International Society for Professional Innovation Management (ISPIM) , 2015Conference paper (Refereed)
    Abstract [en]

    Intensified and matured use of internet-based technologies aimed to facilitate development and innovation are increasingly characterized by a mixture of physical and digital locations; commonly referred to as places and spaces. The aim of this paper was therefore to identify different types of places and spaces central for the innovation milieus and processes of Living Lab projects, illustrate their impact on both process and results, and develop guidelines for space that can be designed in order to facilitate value-driven and democratized innovation. Based on a literature review and a cross case analyses different aspects of space, relevant for Innovation and Living Lab studies, have been identified: 1) local-global; 2) physical and digital, and 3) private-public. In the paper we focus on these concepts as tools for understanding present day innovation and we examples of how digital technology has influenced placement and permeability in relation to place and space.

  • 231.
    Bergvall-Kåreborn, Birgitta
    et al.
    Luleå University of Technology, Luleå, Sweden.
    Ihlström Eriksson, Carina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Ståhlbröst, Anna
    Luleå University of Technology, Luleå, Sweden.
    Places and Spaces within Living Labs2015In: Technology Innovation Management Review, ISSN 1927-0321, E-ISSN 1927-0321, Vol. 5, no 12, p. 37-47Article in journal (Refereed)
    Abstract [en]

    In this article, we propose the concepts of places and spaces as conceptual tools to facilitate the organization of innovation activities within living labs. We have taken a pragmatic perspective on these concepts regarding how they are integrated in design situations, and how different types of places and spaces can facilitate or hinder innovation. We have found that, by applying openness, realism, and influence in the different spaces of our living lab milieus, they have transformed into many different places depending on the stakeholders involved, the methods chosen, and the facilitation of activities. Hence, by understanding this line of reasoning, living lab managers can make more informed decisions and plans for innovation activities.

  • 232.
    Bergvall-Kåreborn, Birgitta
    et al.
    Luleå University of Technology.
    Ihlström Eriksson, Carina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Ståhlbröst, Anna
    Luleå University of Technology.
    Svensson, Jesper
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    A Milieu for Innovation: Defining Living Labs2009In: Stimulating recovery: the role of innovation management : proceedings of the 2nd ISPIM Innovation Symposium, New York City, USA, 6-9 December 2009 / [ed] K.R.E. Huizingh et al, New York: ISPIM , 2009, p. 12-Conference paper (Refereed)
    Abstract [en]

    A new trend of user involvement in open innovation processes has emerged. Concurring with this trend the Living Lab concept has been re-vitalized. This concept has attracted attention lately, but there exist no coherent view. In this paper we discuss and define the concept and propose five key components and five key principles for Living Labs based on experiences from over 30 development and research projects within two Living Labs, Botnia Living Lab and Halmstad Living Lab. The key components are: ICT & Infrastructure; Management; Partners & Users; Research; and Approach. The key principles are: Openness; Influence; Realism; Value; and Sustainability. Our proposed definition of a Living Lab is: A Living Lab is a user-centric innovation milieu built on every-day practice and research, with an approach that facilitates user influence in open and distributed innovation processes engaging all relevant partners in real-life contexts, aiming to create sustainable values.

  • 233.
    Bernard, Florian
    et al.
    MPI Informatics, Saarland Informatics Campus, Saarbrücken, Germany.
    Thunberg, Johan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Goncalves, Jorge
    LCSB, University of Luxembourg, Esch-sur-Alzette, Luxembourg.
    Theobalt, Christian
    MPI Informatics, Saarland Informatics Campus, Saarbrücken, Germany.
    Synchronisation of partial multi-matchings via non-negative factorisations2019In: Pattern Recognition, ISSN 0031-3203, E-ISSN 1873-5142, Vol. 92, p. 146-155Article in journal (Refereed)
    Abstract [en]

    In this work we study permutation synchronisation for the challenging case of partial permutations, which plays an important role for the problem of matching multiple objects (e.g. images or shapes). The term synchronisation refers to the property that the set of pairwise matchings is cycle-consistent, i.e. in the full matching case all compositions of pairwise matchings over cycles must be equal to the identity. Motivated by clustering and matrix factorisation perspectives of cycle-consistency, we derive an algo- rithm to tackle the permutation synchronisation problem based on non-negative factorisations. In order to deal with the inherent non-convexity of the permutation synchronisation problem, we use an initialisation procedure based on a novel rotation scheme applied to the solution of the spectral relaxation. Moreover, this rotation scheme facilitates a convenient Euclidean projection to obtain a binary solution after solving our relaxed problem. In contrast to state-of-the-art methods, our approach is guaranteed to produce cycle-consistent results. We experimentally demonstrate the efficacy of our method and show that it achieves better results compared to existing methods. © 2019 Elsevier Ltd

  • 234.
    Bhanu, Bir
    et al.
    University of California at Riverside, USA.
    Ratha, Nalini K.
    IBM T.J. Watson Research Center, USA.
    Kumar, Vijay
    Carnegie Mellon University, USA.
    Chellappa, Rama
    University of Maryland.
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Guest Editorial: Special Issue on Human Detection and Recognition2007In: IEEE Transactions on Information Forensics and Security, ISSN 1556-6013, E-ISSN 1556-6021, Vol. 2, no 3 part 2, p. 489-490Article in journal (Refereed)
    Abstract [en]

    The 12 regular papers and three correspondences in this special issue focus on human detection and recognition. The papers represent gait, face (3-D, 2-D, video), iris, palmprint, cardiac sounds, and vulnerability of biometrics and protection against the spoof attacks.

  • 235.
    Biba, Panagiota
    Halmstad University, School of Information Technology.
    New waviness measurement system using RGB LED lights2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Due to the rapid technological developments in the car industry and the high quality demands of customers, manufacturers and researchers focus on the reduction of surface roughness making use of various surface topography measurement systems. This master thesis focuses on development of a waviness measurement system (WMS) at Volvo Cars where light from different heights and angles illuminates the surface of an extended object in order to acquire images with different intensities due to shadowing effect and reflection. With this, surface irregularities and imperfections can be detected both in polished and unpolished surfaces for improving the car panels in the manufacturing process.  The initial WMS idea was to illuminate the surface at different heights from the four corners of a dark room using 20 flash lights and a camera positioned exactly on the top of the surface in the middle of the room. The first light goes on and the image is acquired. This procedure continues for all flash lights in 19s.The acquired images were evaluated by Matlab application. With the new WMS system flash lights are replaced by 32 RGB COB LED lights using the DMX512 protocol to communicate with them. The system runs in 9s which is half the time of the old WMS system. New LabView and Matlab codes were adjusted to the new parameters and devices. In the end, measurements were taken with different surfaces, exposure times and color lights. Details of the new devices and software are analyzed in this thesis.  

  • 236.
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Fingerprint features2009In: Encyclopedia of biometrics / [ed] Stan Z. Li, New York: Springer-Verlag New York, 2009, p. 465-473Chapter in book (Other academic)
  • 237.
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Multiple experts2009In: Encyclopedia of biometrics / [ed] Stan Z. Li & Anil Jain, Springer, 2009, p. 986-993Chapter in book (Other academic)
  • 238.
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Vision with Direction: A Systematic Introduction to Image Processing and Computer Vision2006Book (Refereed)
    Abstract [en]

    Presents a systematic, mathematically rigorous examination of modern signal processing concepts used in computer vision and image analysis. This book is illustrated with 4-color graphics and applications, including biometric person authentication, texture analysis, optical character recognition, motion estimation and tracking.

  • 239.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Tomas
    TietoEnator ArosTech AB, Linköping.
    Symmetry derivatives of Gaussians illustrated by cross tracking2001Report (Other academic)
    Abstract [en]

    We propose a family of complex differential operators, symmetry derivatives, for pattern recognition in images. We present three theorems on their properties as applied to Gaussians. These show that all orders of symmetry derivatives of Gaussians yield compact expressions obtained by replacing the original differential polynomial with an ordinary polynomial. Just like Gaussians, the symmetry derivatives of Gaussians are (form) invariant to Fourier transform, that is they are rescaled versions of the original. As a result, the symmetry derivatives of Gaussians are closed under the convolution operator, i.e. they map on a member of the family when convolved with each other. Since Gaussians are utilized extensively in image processing, the revealed properties have practical consequences, e.g. when designing filters and filtering schemes that are unbiased w.r.t. orientation (isotropic). A use of these results is illustrated by an application: tracking the cross markers in long image sequences from vehicle crash tests. The implementation and the results of this application are discussed in terms of the theorems presented, along with conclusions.

  • 240.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Tomas
    TietoEnator ArosTech, Linköping, Sweden.
    Nilsson, Kenneth
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Orientation fields filtering by derivatives of a Gaussian2003In: Proceedings of the 13th Scandinavian Conference on Image Analysis (SCIA 2003), Halmstad, Sweden, Date: jun 29-jul 02, 2003, Berlin: Springer Berlin/Heidelberg, 2003, Vol. LNCS-2749, p. 19-27Conference paper (Other academic)
    Abstract [en]

    We suggest a set of complex differential operators, symmetry derivatives, that can be used for matching and pattern recognition. We present results on the invariance properties of these. These show that all orders of symmetry derivatives of Gaussians yield a remarkable invariance : they are obtained by replacing the original differential polynomial with the same polynomial but using ordinary scalars. Moreover, these functions are closed under convolution and they are invariant to the Fourier transform. The revealed properties have practical consequences for local orientation based feature extraction. This is shown by two applications: i) tracking markers in vehicle tests ii) alignment of fingerprints.

  • 241.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Tomas
    TietoEnator AB, Storg. 3, 58223 Linköping, Sweden.
    Nilsson, Kenneth
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Recognition by symmetry derivatives and the generalized structure tensor2004In: IEEE Transaction on Pattern Analysis and Machine Intelligence, ISSN 0162-8828, E-ISSN 1939-3539, Vol. 26, no 12, p. 1590-1605Article in journal (Refereed)
    Abstract [en]

    We suggest a set of complex differential operators that can be used to produce and filter dense orientation (tensor) fields for feature extraction, matching, and pattern recognition. We present results on the invariance properties of these operators, that we call symmetry derivatives. These show that, in contrast to ordinary derivatives, all orders of symmetry derivatives of Gaussians yield a remarkable invariance: they are obtained by replacing the original differential polynomial with the same polynomial, but using ordinary coordinates x and y corresponding to partial derivatives. Moreover, the symmetry derivatives of Gaussians are closed under the convolution operator and they are invariant to the Fourier transform. The equivalent of the structure tensor, representing and extracting orientations of curve patterns, had previously been shown to hold in harmonic coordinates in a nearly identical manner. As a result, positions, orientations, and certainties of intricate patterns, e.g., spirals, crosses, parabolic shapes, can be modeled by use of symmetry derivatives of Gaussians with greater analytical precision as well as computational efficiency. Since Gaussians and their derivatives are utilized extensively in image processing, the revealed properties have practical consequences for local orientation based feature extraction. The usefulness of these results is demonstrated by two applications:

    1. tracking cross markers in long image sequences from vehicle crash tests and
    2. alignment of noisy fingerprints.
  • 242.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Choy, Kwok
    Halmstad University.
    Olsson, Henrik
    Halmstad University.
    Evidence on skill differences of women and men concerning face recognition2001In: Audio- and video-based biometric person authentication: Third International Conference, AVBPA 2001, Halmstad, Sweden, June 6-8, 2001 : proceedings / [ed] Josef Bigun, Fabrizio Smeraldi, (eds.), Berlin: Springer, 2001, p. 44-51Conference paper (Other academic)
    Abstract [en]

    We present a cognitive study regarding face recognition skills of women and men. The results reveal that there are in the average sizable skill differences between women and men in human face recognition. The women had higher correct answer frequencies then men in all face recognition questions they answered. In difficult questions, those which had fewer correct answers than other questions, the performance of the best skilled women were remarkably higher than the best skilled men. The lack of caricature type information (high spatial frequencies) hampers the recognition task significantly more than the lack of silhouette and shading (low spatial frequencies) information, according to our findings. Furthermore, the results confirmed the previous findings that hair style and facial expressions degrades the face recognition performance of humans significantly. The reported results concern 1838 individuals and the study was effectuated by means of Internet.

  • 243.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Choy, Kwok-wai
    Olsson, Henrik
    Evidence on skill differences of women and men concerning face recognition2001Report (Other academic)
    Abstract [en]

    We present a cognitive study regarding face recognition skills of women and men. The results reveal that there are in the average sizable skill differences between women and men in human face recognition. The women had higher correct answer frequencies then men in all face recognition questions they answered. In difficult questions, those which had fewer correct answers than other questions, the performance of the best skilled women were remarkably higher than the best skilled men. The lack of caricature type information (high spatial frequencies) hampers the recognition task significantly more than the lack of silhouette and shading (low spatial frequencies) information, according to our findings. Furthermore, the results confirmed the previous findings that hair style and facial expressions degrades the face recognition performance of humans significantly. The reported results concern 1838 individuals and the study was effectuated by means of Internet.

  • 244.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Fierrez-Aguilar, J.
    Universidad Politecnica de Madrid, Spain.
    Ortega-Garcia, J.
    Universidad Politecnica de Madrid, Spain.
    Gonzalez-Rodriguez, J.
    Universidad Politecnica de Madrid, Spain.
    Combining Biometric Evidence for Person Authentication2005In: Advanced Studies in Biometrics: Summer School on Biometrics, Alghero, Italy, June 2-6, 2003 / [ed] Tistarelli, Massimo; Bigun, Josef; Grosso, Enrico, Berlin: Springer Berlin/Heidelberg, 2005, p. 1-18Conference paper (Other academic)
    Abstract [en]

    Humans are excellent experts in person recognition and yet they do not perform excessively well in recognizing others only based on one modality such as single facial image. Experimental evidence of this fact is reported concluding that even human authentication relies on multimodal signal analysis. The elements of automatic multimodal authentication along with system models are then presented. These include the machine experts as well as machine supervisors. In particular, fingerprint and speech based systems will serve as illustration. A signal adaptive supervisor based on the input biometric signal quality is evaluated.

  • 245.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Fiérrez-Aguilar, Julián
    Universidad Autonoma de Madrid, Biometric Recognition Group - ATVS, Madrid, Spain.
    Ortega-García, Javier
    Universidad Autonoma de Madrid, Biometric Recognition Group - ATVS, Madrid, Spain.
    González-Rodríguez, Joaquín
    Universidad Autonoma de Madrid, Biometric Recognition Group - ATVS, Madrid, Spain.
    Multimodal biometric authentication using quality signals in mobile communications2003In: Proceedings - 12th International Conference on Image Analysis and Processing, ICIAP 2003, Los Alamitos, USA: IEEE Computer Society, 2003, p. 2-11Conference paper (Other academic)
    Abstract [en]

    The elements of multimodal authentication along with system models are presented. These include the machine experts as well as machine supervisors. In particular fingerprint and speech based systems will serve as illustration of a mobile authentication application. A novel signal adaptive supervisor, based on the input biometric signal quality is evaluated. Experimental results on data collected from mobile telephones are reported demonstrating the benefits of the proposed scheme. © 2003 IEEE.

  • 246.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Fronthaler, Hartwig
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Kollreider, Klaus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Assuring liveness in biometric identity authentication by real-time face tracking2004In: CIHSPS 2004: proceedings of the 2004 IEEE International Conference on Computational Intelligence for Homeland Security and Personal Safety : S. Giuliano, Venice, Italy, 21-22 July 2004 / [ed] IEEE, Piscataway, N.J.: IEEE Press, 2004, p. 104-111Conference paper (Refereed)
    Abstract [en]

    A system that combines real-time face tracking as well as the localization of facial landmarks in order to improve the authenticity of fingerprint recognition is introduced. The intended purpose of this application is to assist in securing public areas and individuals, in addition to enforce that the collected sensor data in a multi modal person authentication system originate front present persons, i.e. the system is not under a so called play back attack. Facial features are extracted with the help of Gabor filters and classified by SVM experts. For real-time performance, selected points from a retinotopic grid are used to form regional face models. Additionally only a subset of the Gabor decomposition is used for different face regions. The second modality presented is texture-based fingerprint recognition, exploiting linear symmetry. Experimental results on the proposed system are presented.

  • 247.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Gustavsson, TomasChalmers University of Technology, Department of Signals and Systems, Gothenburg, Sweden.
    Image analysis: 13th Scandinavian Conference, SCIA 2003, Halmstad, Sweden, June 29-July 2, 2003, Proceedings2003Conference proceedings (editor) (Other academic)
    Abstract [en]

    This book constitutes the refeered proceedings of the 13th Scandinavian Conference on Image Analysis, SCIA 2003, held in Halmstad, Sweden in June/July 2003.The 148 revised full papers presented together with 6 invited contributions were carefully reviewed and selected for presentation. The papers are organized in topical sections on feature extraction, depth and surface, shape analysis, coding and representation, motion analysis, medical image processing, color analysis, texture analysis, indexing and categorization, and segmentation and spatial grouping.

  • 248.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Karlsson, Stefan M.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Histogram of directions by the structure tensor2011In: Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies, New York, NY: Association for Computing Machinery (ACM), 2011Conference paper (Refereed)
    Abstract [en]

    Many low-level features, as well as varying methods of extraction and interpretation rely on directionality analysis (for example the Hough transform, Gabor filters, SIFT descriptors and the structure tensor). The theory of the gradient based structure tensor (a.k.a. the second moment matrix) is a very well suited theoretical platform in which to analyze and explain the similarities and connections (indeed often equivalence) of supposedly different methods and features that deal with image directionality. Of special interest to this study is the SIFT descriptors (histogram of oriented gradients, HOGs). Our analysis of interrelationships of prominent directionality analysis tools offers the possibility of computation of HOGs without binning, in an algorithm of comparative time complexity.

  • 249.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Malmqvist, Kerstin
    Proceedings: Symposium on image analysis, Halmstad March 7-8, 20002000Conference proceedings (editor) (Other academic)
  • 250.
    Bigun, Josef
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Mikaelyan, Anna
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Dense frequency maps by Structure Tensor and logarithmic scale space: application to forensic fingerprintsManuscript (preprint) (Other academic)
    Abstract [en]

    Increasingly, reliable absolute frequency and orientation maps are needed, e.g. for image enhancement. Less studied is however the mutual dependence of both maps, and how to estimate them when none is known initially. We introduce a logarithmic scale space generated by the trace of Structure Tensor to study the relationship. The scale space is non-linear and absolute frequency estimation is reduced to an orientation estimation in it. We show that this offers significant advantages, including construction of efficient estimation methods, using Structure Tensor yielding dense maps of absolute frequency as well as orientation. In fingerprints, both maps can successively improve each other, combined in an image enhancement scheme via Gabor filtering. We verify that the suggested method compares favorably with state of the art, using forensic fingerprints recognition as test bed, and using test images where the ground truth is known. Furthermore, we suggest a novel continuous ridge counting method, relying only on dense absolute frequency and orientation maps, without ridge detection, thinning, etc. We present new evidence that the neighborhoods of the absolute frequency map are useful attributes of minutiae. In experiments, we use public data sets to support the conclusions.

2345678 201 - 250 of 2013
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