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  • 101.
    Aramrattana, Maytheewat
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Modelling and Simulation for Evaluation of Cooperative Intelligent Transport System Functions2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Future vehicles are expected to be equipped with wireless communication tech- nology, that enables them to be “connected” to each others and road infras- tructures. Complementing current autonomous vehicles and automated driving systems, the wireless communication allows the vehicles to interact, cooperate, and be aware of its surroundings beyond their own sensors’ range. Such sys- tems are often referred to as Cooperative Intelligent Transport Systems (C-ITS), which aims to provide extra safety, efficiency, and sustainability to transporta- tion systems. Several C-ITS applications are under development and will require thorough testing and evaluation before their deployment in the real-world. C- ITS depend on several sub-systems, which increase their complexity, and makes them difficult to evaluate.

    Simulations are often used to evaluate many different automotive appli- cations, including C-ITS. Although they have been used extensively, simulation tools dedicated to determine all aspects of C-ITS are rare, especially human fac- tors aspects, which are often ignored. The majority of the simulation tools for C-ITS rely heavily on different combinations of network and traffic simulators. The human factors issues have been covered in only a few C-ITS simulation tools, that involve a driving simulator. Therefore, in this thesis, a C-ITS simu- lation framework that combines driving, network, and traffic simulators is pre- sented. The simulation framework is able to evaluate C-ITS applications from three perspectives; a) human driver; b) wireless communication; and c) traffic systems.

    Cooperative Adaptive Cruise Control (CACC) and its applications are cho- sen as the first set of C-ITS functions to be evaluated. Example scenarios from CACC and platoon merging applications are presented, and used as test cases for the simulation framework, as well as to elaborate potential usages of it. Moreover, approaches, results, and challenges from composing the simulation framework are presented and discussed. The results shows the usefulness of the proposed simulation framework.

  • 102.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Detournay, J.
    Swedish National Transport Research Institute, Gothenburg, SE-402 78, Sweden.
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Frimodig, Viktor
    Halmstad University, School of Information Technology.
    Jansson, Oscar Uddman
    Swedish National Transport Research Institute, Gothenburg, SE-402 78, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mostowski, Wojciech
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Díez Rodríguez, Víctor
    Halmstad University, School of Information Technology.
    Rosenstatter, Thomas
    Halmstad University, School of Information Technology.
    Shahanoor, Golam
    Halmstad University, School of Information Technology.
    Team Halmstad Approach to Cooperative Driving in the Grand Cooperative Driving Challenge 20162018In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 19, no 4, p. 1248-1261Article in journal (Refereed)
    Abstract [en]

    This paper is an experience report of team Halmstad from the participation in a competition organised by the i-GAME project, the Grand Cooperative Driving Challenge 2016. The competition was held in Helmond, The Netherlands, during the last weekend of May 2016. We give an overview of our car’s control and communication system that was developed for the competition following the requirements and specifications of the i-GAME project. In particular, we describe our implementation of cooperative adaptive cruise control, our solution to the communication and logging requirements, as well as the high level decision making support. For the actual competition we did not manage to completely reach all of the goals set out by the organizers as well as ourselves. However, this did not prevent us from outperforming the competition. Moreover, the competition allowed us to collect data for further evaluation of our solutions to cooperative driving. Thus, we discuss what we believe were the strong points of our system, and discuss post-competition evaluation of the developments that were not fully integrated into our system during competition time. © 2000-2011 IEEE.

  • 103.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. RISE Viktoria, Göteborg, Sweden.
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Safety Analysis of Cooperative Adaptive Cruise Control in Vehicle Cut-in Situations2017In: Proceedings of 2017 4th International Symposium on Future Active Safety Technology towards Zero-Traffic-Accidents (FAST-zero), Society of Automotive Engineers of Japan , 2017, article id 20174621Conference paper (Refereed)
    Abstract [en]

    Cooperative adaptive cruise control (CACC) is a cooperative intelligent transport systems (C-ITS) function, which especially when used in platooning applications, possess many expected benefits including efficient road space utilization and reduced fuel consumption. Cut-in manoeuvres in platoons can potentially reduce those benefits, and are not desired from a safety point of view. Unfortunately, in realistic traffic scenarios, cut-in manoeuvres can be expected, especially from non-connected vehicles. In this paper two different controllers for platooning are explored, aiming at maintaining the safety of the platoon while a vehicle is cutting in from the adjacent lane. A realistic scenario, where a human driver performs the cut-in manoeuvre is used to demonstrate the effectiveness of the controllers. Safety analysis of CACC controllers using time to collision (TTC) under such situation is presented. The analysis using TTC indicate that, although potential risks are always high in CACC applications such as platooning due to the small inter-vehicular distances, dangerous TTC (TTC < 6 seconds) is not frequent. Future research directions are also discussed along with the results.

  • 104.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Göteborg, Sweden.
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. RISE Viktoria, Göteborg, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Göteborg, Sweden.
    Safety Evaluation of Highway Platooning Under a Cut-In Situation Using Simulation2018In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016Article in journal (Refereed)
    Abstract [en]

    Platooning refers to an application, where a group of connected and automated vehicles follow a lead vehicle autonomously, with short inter-vehicular distances. At merging points on highways such as on-ramp, platoons could encounter manually driven vehicles, which are merging on to the highways. In some situations, the manually driven vehicles could end up between the platooning vehicles. Such situations are expected and known as “cut-in” situations. This paper presents a simulation study of a cut-in situation, where a platoon of five vehicles encounter a manually driven vehicle at a merging point of a highway. The manually driven vehicle is driven by 37 test persons using a driving simulator. For the platooning vehicles, two longitudinal controllers with four gap settings between the platooning vehicles, i.e. 15 meters, 22.5 meters, 30 meters, and 42.5 meters, are evaluated. Results summarizing cut-in behaviours and how the participants perceived the situation are presented. Furthermore, the situation is assessed using safety indicators based on time-to-collision.

  • 105.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. RISE Viktoria, Gothenburg, Sweden.
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Simulation of Cut-In by Manually Driven Vehicles in Platooning Scenarios2017In: 2017 IEEE 20th International Conference on Intelligent Transportation Systems (ITSC), Piscataway, NJ: IEEE, 2017, p. 1-6Conference paper (Refereed)
    Abstract [en]

    In the near future, Cooperative Intelligent Transport System (C-ITS) applications are expected to be deployed. To support this, simulation is often used to design and evaluate the applications during the early development phases. Simulations of C-ITS scenarios often assume a fleet of homogeneous vehicles within the transportation system. In contrast, once C-ITS is deployed, the traffic scenarios will consist of a mixture of connected and non-connected vehicles, which, in addition, can be driven manually or automatically. Such mixed cases are rarely analysed, especially those where manually driven vehicles are involved. Therefore, this paper presents a C-ITS simulation framework, which incorporates a manually driven car through a driving simulator interacting with a traffic simulator, and a communication simulator, which together enable modelling and analysis of C-ITS applications and scenarios. Furthermore, example usages in the scenarios, where a manually driven vehicle cut-in to a platoon of Cooperative Adaptive Cruise Control (CACC) equipped vehicles are presented. © 2017 IEEE.

  • 106.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. Viktoria Swedish ICT, Gothenburg, Sweden.
    Dimensions of Cooperative Driving, ITS and Automation2015In: 2015 IEEE Intelligent Vehicles Symposium (IV), Piscataway, NJ: IEEE Press, 2015, p. 144-149Conference paper (Refereed)
    Abstract [en]

    Wireless technology supporting vehicle-to-vehicle (V2V), and vehicle-to-infrastructure (V2I) communication, allow vehicles and infrastructures to exchange information, and cooperate. Cooperation among the actors in an intelligent transport system (ITS) can introduce several benefits, for instance, increase safety, comfort, efficiency. Automation has also evolved in vehicle control and active safety functions. Combining cooperation and automation would enable more advanced functions such as automated highway merge and negotiating right-of-way in a cooperative intersection. However, the combination have influences on the structure of the overall transport systems as well as on its behaviour. In order to provide a common understanding of such systems, this paper presents an analysis of cooperative ITS (C-ITS) with regard to dimensions of cooperation. It also presents possible influence on driving behaviour and challenges in deployment and automation of C-ITS.

  • 107.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    A simulation framework for cooperative intelligent transport systems testing and evaluation2019In: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 61, p. 268-280Article in journal (Refereed)
    Abstract [en]

    Connected and automated driving in the context of cooperative intelligent transport systems (C-ITS) is an emerging area in transport systems research. Interaction and cooperation between actors in transport systems are now enabled by the connectivity by means of vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. To ensure the goals of C-ITS, which are safer and more efficient transport systems, testing and evaluation are required before deployment of C-ITS applications. Therefore, this paper presents a simulation framework—consisting of driving-, traffic-, and network-simulators—for testing and evaluation of C-ITS applications. Examples of cooperative adaptive cruise control (CACC) applications are presented, and are used as test cases for the simulation framework as well as to elaborate on potential use cases of it. Challenges from combining the simulators into one framework, and limitations are reported and discussed. Finally, the paper concludes with future development directions, and applications of the simulation framework in testing and evaluation of C-ITS. © 2017 Elsevier Ltd. All rights reserved.

  • 108.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Cooperative Driving Simulation2016In: Proceedings of the Driving Simulation Conference 2016, 2016, p. 123-132Conference paper (Refereed)
    Abstract [en]

    For a few decades, driving simulators have been supporting research and development of advanced driver assistance systems (ADAS). In the near future, connected vehicles are expected to be deployed. Driving simulators will need to support evaluation of cooperative driving applications within cooperative intelligent transportation systems (C-ITS) scenarios. C-ITS utilize vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. Simulation of the inter vehicle communication is often not supported in driving simulators. On the other hand, previous efforts have been made to connect network simulators and traffic simulators, to perform C-ITS simulations. Nevertheless, interactions between actors in the system is an essential aspect of C-ITS. Driving simulators can provide the opportunity to study interactions and reactions of human drivers to the system. This paper present simulation of a C-ITS scenario using a combination of driving, network, and traffic simulators. The architecture of the solution and important challenges of the integration are presented. A scenario from Grand Cooperative Driving Challenge (GCDC) 2016 is implemented in the simulator as an example use case. Lastly, potential usages and future developments are discussed.

  • 109.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Extended Driving Simulator for Evaluation of Cooperative Intelligent Transport Systems2016In: SIGSIM-PADS '16: Proceedings of the 2016 annual ACM Conference on SIGSIM Principles of Advanced Discrete Simulation, New York: ACM Digital Library, 2016, p. 255-278Conference paper (Refereed)
    Abstract [en]

    Vehicles in cooperative intelligent transport systems (C-ITS) often need to interact with each other in order to achieve their goals, safe and efficient transport services. Since human drivers are still expected to be involved in C-ITS, driving simulators are appropriate tools for evaluation of the C-ITS functions. However, driving simulators often simplify the interactions or influences from the ego vehicle on the traffic. Moreover, they normally do not support vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication, which is the main enabler for C-ITS. Therefore, to increase the C-ITS evaluation capability, a solution on how to extend a driving simulator with traffic and network simulators to handle cooperative systems is presented as a result of this paper. Evaluation of the result using two use cases is presented. And, the observed limitations and challenges of the solution are reported and discussed. © 2016 ACM, Inc.

  • 110.
    Aramrattana, Maytheewat
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Patel, Raj Haresh
    Communication Systems Department, EURECOM, Sophia-Antipolis, France.
    Englund, Cristofer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). RISE Viktoria, Gothenburg, Sweden.
    Härri, Jérôme
    Communication Systems Department, EURECOM, Sophia-Antipolis, France.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Bonnet, Christian
    Communication Systems Department, EURECOM, Sophia-Antipolis, France.
    Evaluating Model Mismatch Impacting CACC Controllers in Mixed2018In: 2018 IEEE Intelligent Vehicles Symposium (IV), IEEE, 2018, p. 1867-1872Conference paper (Refereed)
    Abstract [en]

    At early market penetration, automated vehicles will share the road with legacy vehicles. For a safe transportation system, automated vehicle controllers therefore need to estimate the behavior of the legacy vehicles. However, mismatches between the estimated and real human behaviors can lead to inefficient control inputs, and even collisions in the worst case. In this paper, we propose a framework for evaluating the impact of model mismatch by interfacing a controller under test with a driving simulator. As a proof- of-concept, an algorithm based on Model Predictive Control (MPC) is evaluated in a braking scenario. We show how model mismatch between estimated and real human behavior can lead to a decrease in avoided collisions by almost 46%, and an increase in discomfort by almost 91%. Model mismatch is therefore non-negligible and the proposed framework is a unique method to evaluate them. © 2018 IEEE.

  • 111.
    Arashlouzadeh, Amir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Surface Roughness Measurment: Multi-bandFrequency Shift Interferometer based onPolarization Measurement2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Optical measurement techniques have been gaining ground for their vast applications in industry and scientific purposes. These techniques are beneficial comparing to the mechanical methods. Non-intrusive, robust, high accuracy and small measurement volume are some of the advantages of the optical metrology. However, these approaches are expensive. Interferometry is one of the most prominent principles of these optical measurements. It employs the study of fringe patterns in order to model surface roughness with a high precision up to nano-meter scale. In this thesis, we mainly focus on the multi-band frequency shifting interferometry based on polarization measurement for 3D surface modeling. The system has advantages such as it is very accurate and there is no need of a phase unwrapping algorithm. Like the conventional phase shifting interferometry, four intensity images are recorded for the four polarization states correspondingly and then the images are processed by MATLAB and the final results are provided. In this technique the need for three cameras and offset correction between the cameras has been revised and optimized by using only one camera. In the first setup trial, a fiber optic switch has been used which does not lead to the desired results and then the switch has been removed and the corresponding images are satisfactory.

  • 112.
    Araujo, Hugo
    et al.
    Universidade Federal de Pernambuco, Recife, PE, Brazil.
    Carvalho, Gustavo
    Universidade Federal de Pernambuco, Recife, PE, Brazil.
    Mohaqeqi, Morteza
    Uppsala University, Uppsala, Sweden.
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). University of Leicester, Leicester, UK.
    Sampaio, Augusto
    Universidade Federal de Pernambuco, Recife, PE, Brazil.
    Sound conformance testing for cyber-physical systems: Theory and implementation2017In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 162, p. 35-54Article in journal (Refereed)
    Abstract [en]

    Conformance testing is a formal and structured approach to verifying system correctness. We propose a conformance testing algorithm for cyber-physical systems, based on the notion of hybrid conformance by Abbas and Fainekos. We show how the dynamics of system specification and the sampling rate play an essential role in making sound verdicts. We specify and prove error bounds that lead to sound test-suites for a given specification and a given sampling rate. We use reachability analysis to find such bounds and implement the proposed approach using the CORA toolbox in Matlab. We apply the implemented approach on a case study from the automotive domain. © 2017 The Author(s).

  • 113.
    Araujo, Hugo
    et al.
    Universidade Federal de Pernambuco, Recife, PE, Brazil.
    Carvalho, Gustavo
    Universidade Federal de Pernambuco, Recife, PE, Brazil.
    Sampaio, Augusto
    Universidade Federal de Pernambuco, Recife, PE, Brazil.
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Taromirad, Masoumeh
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    A Process for Sound Conformance Testing of Cyber-Physical Systems2017In: 2017 IEEE International Conference on Software Testing, Verification and Validation Workshops (ICSTW) / [ed] Randall Bilof, Los Alamitos, CA: IEEE Computer Society, 2017, p. 46-50, article id 7899032Conference paper (Refereed)
    Abstract [en]

    We present a process for sound conformance testing of cyber-physical systems, which involves functional but also non-functional aspects. The process starts with a hybrid model of cyber-physical systems in which the correct behavior of the system (at its interface level) is specified. Such a model captures both discrete behavior and evolution of continuous dynamics of the system in time. Since conformance testing inherently involves comparing continuous dynamics, the key parameters of the process are (1) the conformance bounds defining when two signals are sufficiently close to each other, and (2) the permitted error margin in the conformance analysis introduced by sampling of continuous signals. The final parameter of this process is (3) finding (and adjusting) the sampling rate of the dynamic behavior. In the specified process, we provide different alternatives for fixing the error margin of the conformance testing if the sampling rate is fixed, establishing the sampling rate if the error margin is fixed and finding conformance bounds once the sampling rate and the error margin are fixed. © 2017 IEEE.

  • 114.
    Aronsson, Erik
    Halmstad University, School of Information Technology.
    Biometric Authentication and Penetration of Smartphones2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study aims to examine the function and vulnerabilities of biometric systemsintegrated in smartphones, as well as techniques for circumventing the securityof these systems. These techniques are then used against a selection of smart-phones in order to gauge the resilience of their biometric security. The function,vulnerabilities, and techniques associated with these systems are compiled usinga literature study of published papers and books on the subject. The performedexperiments apply these techniques in the form of presentation attacks directed atthe fingerprint-, face- and iris recognition systems of the examined smartphones.The result of the experiments showed significant differences between the differentsmartphones, where some exhibited flawless security and others showed significantsecurity flaws. Both fingerprint and face recognition systems were successfullycircumvented, while none of the iris recognition systems were breached. No clearlink could be observed between the cost of the device and success rate of attacks,while only devices using the Android operating system were breached. The resultsundeniably showed that some smartphones are vulnerable to the employed tech-niques. It also showed that some of the tested devices had managed to implementmeasures to counteract the applied presentation attacks. The root cause of thevulnerabilities showcased in the experiment is due to the fact that biometric traitscan be copied and reproduced, highlighting a basic flaw of such systems.

  • 115.
    Aronsson, John
    et al.
    Halmstad University, School of Information Technology.
    Bolmér, Percy
    Halmstad University, School of Information Technology.
    Hur forensiska verktyg påverkar integriteten på mobiltelefoner2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The rising use of smartphones and other mobile devices in society today has resulted in a higher prevalence of these in crimes and crime investigations. The information in these devices must be extracted and the integrity of the extracted information assured. The goal of this project is to determine whether the two forensic software programs Xry and Encase tamper with the extracted data. To answer this, a literary study together with an interview and two experiments were performed. The result from the experiments determined that data changes occured between extractions. Further analysis explained the changes to be caused by the devices themselves, and as a consequence of rooting. The conclusion drawn from the result was that the softwares programs did not tamper with the material during the extraction-process.

  • 116.
    Arts, Thomas
    et al.
    Quviq AB, Gothenburg, Sweden.
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Automatic Consequence Analysis of Automotive Standards (AUTO-CAAS) [Position Paper]2015In: WASA '15: Proceedings of the First International Workshop on Automotive Software Architecture / [ed] Yanja Dajsuren, Harald Altinger & Miroslaw Staron, New York, NY: ACM Press, 2015, p. 35-38Conference paper (Refereed)
    Abstract [en]

    This paper provides some background and the roadmap of the AUTO-CAAS project, which is a 3-year project financed by the Swedish Knowledge Foundation and is ongoing as a joint project among three academic and industrial partners. The aim of the project is to exploit the formal models of the AUTOSAR standard, developed by the industrial partner of the project Quviq AB, in order to predict possible future failures in concrete implementations of components. To this end, the deviations from the formal specification will be exploited to generate test-cases that can push concrete components to the corners where such deviation will result in observable failures. The same information will also be used in the diagnosis of otherwise detected failures in order to pinpoint their root causes.

  • 117.
    Arunesh, Sanjana
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Padi Siva, Abhilash
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Robot Assisted Quiz Espying of Learner's: RAQUEL2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As robot technologies develop, many researchers have tried to use robots to support education. Studies have shown that robots can help students develop problem-solving abilities. Robotics technology is being increasingly integrated into the field of education largely due to the appealing image of robot’s young students have. With the rapid development of robotics, it has become feasible to use an educational robot for enhancing learning. This thesis explores the possibility of using robots as an educational tool for being quiz assistant in the class. Here we will be working with the humanoid-like robot and we will teach the robot to be a quiz assistant. The main purpose of this thesis is to have quizzes adapted to an individual knowledge of students in the class. By doing this a teacher can track a student’s performance individually while students will get the performance results as feedback using paper quizzes. When implemented fully, quizzes will be printed, distributed to students, collected from them, corrected, and students will be individually informed by email automatically and rapidly. Conceptually, this is a new approach to learning since frequent, paper-based quizzes become a learning tool in the service of active learning as opposed to their classical use, infrequently used control tool. The thesis scope is limited to contribute to individualization, distribution, and collection of the quizzes, leaving out the automatic correction. This is because for the latter there are already implemented solutions. With individualization, we mean identification of a student taking a certain quiz and conversely, deducing the identity of a student from a collected quiz. For this, we will use face detection and face recognition techniques. To this effect, an algorithm based on the technique Haar cascade by Viola and Jones [1]was used for face detection and Local Binary Pattern Histogram [from now on calledLBPH] method was used for face recognition [2]. This combination is shown to be, precise and maximally avoids illumination problems. The thesis also marks important details missing in the aforementioned paper as well as some drawbacks of the proposed technique. Our results show that RAQUEL system can perform face detection and recognition effectively by identifying and depending on the chosen interfacing strategy, then voicing identification details such as names, individual quiz number and seating row number of the students. Our system can not only be used to identify and bind a student identity to a certain quiz number, but also it can detail class/quiz attendance and keep track of in what order students gave back the quiz papers, helping to assure by biometric identification, that the automatically corrected quiz results are registered for correct student identity.

  • 118.
    Arvidsson, Fredrik
    et al.
    Department of Computer and Information Science, Linköping University.
    Ihlström, Carina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Lundberg, Jonas
    Department of Computer and Information Science, Linköping University.
    Visions of Future News - Consensus or Conflict?2002In: Proceedings of the 25th Information Systems Research Seminar in Scandinavia (IRIS), IRIS , 2002, p. 25-Conference paper (Refereed)
    Abstract [en]

    The move from print to multimedia will cause changes not only to the form of the news service but also the involved processes in the news organizations. The cooperative scenario building technique is used on a number of groups; end-users, management and media professionals to envisioning the news services of the future. We take the perspective of consensus and conflict to illustrate the identified visions. Firstly, we illuminate conflicts and consensus between the groups, regarding their visions and future use scenarios. Secondly, we show the implications of using the cooperative scenariobuilding technique in relation the consensus and conflict perspectives in cooperative design. We conclude that both consensus and conflicts could be found in the scenarios described in the paper and that the cooperative technique was suitable in this context.

  • 119.
    Arvidsson, Jacob
    et al.
    Halmstad University, School of Information Technology.
    Gustafsson, Johan
    Halmstad University, School of Information Technology.
    Upphandlingsprocessen av affärssystem och dess utmaningar: En studie om hur medelstora företag kan hantera utmaningar som uppstår i upphandlingsprocessen av affärssystem2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The acquisition of an Enterprise Resource Planning (ERP) involves a major investment,which often accounts for a large part of the company's total budget. It is close toimpossible to meet all the demands of companies on the system, which makes theprocurement process of Enterprise Resource Planning a complex and difficult process.In the previous research carried out, it is only taken into consideration how largecompanies handle the procurement process, which means that medium-sized companiesend up not accounted for. It is therefore important to investigate how the procurementprocess for medium-sized companies looks and the challenges that arise are dealt with.The result of this study shows both differences and similarities between medium andlarge companies in terms of procurement processes, its challenges and how companieschoose to handle them.

  • 120.
    Ashfaq, Awais
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Predicting clinical outcomes via machine learning on electronic health records2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The rising complexity in healthcare, exacerbated by an ageing population, results in ineffective decision-making leading to detrimental effects on care quality and escalates care costs. Consequently, there is a need for smart decision support systems that can empower clinician's to make better informed care decisions. Decisions, which are not only based on general clinical knowledge and personal experience, but also rest on personalised and precise insights about future patient outcomes. A promising approach is to leverage the ongoing digitization of healthcare that generates unprecedented amounts of clinical data stored in Electronic Health Records (EHRs) and couple it with modern Machine Learning (ML) toolset for clinical decision support, and simultaneously, expand the evidence base of medicine. As promising as it sounds, assimilating complete clinical data that provides a rich perspective of the patient's health state comes with a multitude of data-science challenges that impede efficient learning of ML models. This thesis primarily focuses on learning comprehensive patient representations from EHRs. The key challenges of heterogeneity and temporality in EHR data are addressed using human-derived features appended to contextual embeddings of clinical concepts and Long-Short-Term-Memory networks, respectively. The developed models are empirically evaluated in the context of predicting adverse clinical outcomes such as mortality or hospital readmissions. We also present evidence that, surprisingly, different ML models primarily designed for non-EHR analysis (like language processing and time-series prediction) can be combined and adapted into a single framework to efficiently represent EHR data and predict patient outcomes.

  • 121.
    Ashfaq, Awais
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. KTH Royal Institute of Technology, Stockholm, Sweden.
    Adler, Jonas
    KTH Royal Institute of Technology, Stockholm, Sweden & Elekta Instrument AB, Stockholm, Sweden.
    A modified fuzzy C means algorithm for shading correction in craniofacial CBCT images2017In: CMBEBIH 2017: Proceedings of the International Conference on Medical and Biological Engineering 2017 / [ed] Almir Badnjevic, Singapore: Springer, 2017, Vol. 62, p. 531-538Conference paper (Refereed)
    Abstract [en]

    CBCT images suffer from acute shading artifacts primarily due to scatter. Numerous image-domain correction algorithms have been proposed in the literature that use patient-specific planning CT images to estimate shading contributions in CBCT images. However, in the context of radiosurgery applications such as gamma knife, planning images are often acquired through MRI which impedes the use of polynomial fitting approaches for shading correction. We present a new shading correction approach that is independent of planning CT images. Our algorithm is based on the assumption that true CBCT images follow a uniform volumetric intensity distribution per material, and scatter perturbs this uniform texture by contributing cupping and shading artifacts in the image domain. The framework is a combination of fuzzy C-means coupled with a neighborhood regularization term and Otsu’s method. Experimental results on artificially simulated craniofacial CBCT images are provided to demonstrate the effectiveness of our algorithm. Spatial non-uniformity is reduced from 16% to 7% in soft tissue and from 44% to 8% in bone regions. With shading-correction, thresholding based segmentation accuracy for bone pixels is improved from 85% to 91% when compared to thresholding without shading-correction. The proposed algorithm is thus practical and qualifies as a plug and play extension into any CBCT reconstruction software for shading correction. © Springer Nature Singapore Pte Ltd. 2017.

  • 122.
    Ashfaq, Awais
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Lönn, Stefan
    Research and Development, Region Halland, Sweden.
    Nilsson, Håkan
    Economic Department, Region Halland, Sweden.
    Eriksson, Jonny
    Halland Hospital, Region Halland, Sweden.
    Kwatra, Japneet
    Brigham and Women’s Hospital, US.
    Yasin, Zayed
    Brigham and Women’s Hospital, US.
    Slutzman, Jonathan
    Massachusetts General Hospital, US.
    Wallenfeldt, Thomas
    CGI Group Inc. Consultants to Government and Industries, Sweden.
    Obermeyer, Ziad
    School of Public Health, University of California at Berkeley, US.
    Anderson, Philip
    Department of Emergency Medicine, Brigham & Women’s Hospital, Harvard Medical School, Boston, US..
    Lingman, Markus
    Halland Hospital, Region Halland, Sweden.
    Data Profile: Regional Healthcare Information Platform in Halland, Sweden2019In: International Journal of Epidemiology, ISSN 0300-5771, E-ISSN 1464-3685Article in journal (Refereed)
    Abstract [en]

    Accurate and comprehensive healthcare data coupled with modern analytical tools can play a vital role in enabling care providers to make better-informed decisions, leading to effective and cost-efficient care delivery. This paper describes a novel strategic healthcare analysis and research platform that encapsulates 360-degree pseudo-anonymized data covering clinical, operational capacity and financial data on over 500,000 patients treated since 2009 across all care delivery units in the county of Halland, Sweden. The over-arching goal is to develop a comprehensive healthcare data infrastructure that captures complete care processes at individual, organizational and population levels. These longitudinal linked healthcare data are a valuable tool for research in a broad range of areas including health economy and process development using real world evidence.

    Key messages

    Structured and standardized variables have been linked from different regional healthcare sources into a research information platform including all healthcare visits in the county of Halland in Sweden, from 2009 to date.

    Since 2015, the regional information platform integrates a cost component to each healthcare visit: thus being able to quantify patient level value, safety and cost efficiency across the continuum of care.

  • 123.
    Ashfaq, Awais
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. Halland Hospital, Region Halland, Halmstad, Sweden.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Machine learning in healthcare - a system’s perspective2019In: Proceedings of the ACM SIGKDD Workshop on Epidemiology meets Data Mining and Knowledge Discovery (epiDAMIK) / [ed] B. Aditya Prakash, Anil Vullikanti, Shweta Bansal, Adam Sadelik, Arlington, 2019, p. 14-17Conference paper (Refereed)
    Abstract [en]

    A consequence of the fragmented and siloed healthcare landscape is that patient care (and data) is split along multitude of different facilities and computer systems and enabling interoperability between these systems is hard. The lack interoperability not only hinders continuity of care and burdens providers, but also hinders effective application of Machine Learning (ML) algorithms. Thus, most current ML algorithms, designed to understand patient care and facilitate clinical decision-support, are trained on limited datasets. This approach is analogous to the Newtonian paradigm of Reductionism in which a system is broken down into elementary components and a description of the whole is formed by understanding those components individually. A key limitation of the reductionist approach is that it ignores the component-component interactions and dynamics within the system which are often of prime significance in understanding the overall behaviour of complex adaptive systems (CAS). Healthcare is a CAS.

    Though the application of ML on health data have shown incremental improvements for clinical decision support, ML has a much a broader potential to restructure care delivery as a whole and maximize care value. However, this ML potential remains largely untapped: primarily due to functional limitations of Electronic Health Records (EHR) and the inability to see the healthcare system as a whole. This viewpoint (i) articulates the healthcare as a complex system which has a biological and an organizational perspective, (ii) motivates with examples, the need of a system's approach when addressing healthcare challenges via ML and, (iii) emphasizes to unleash EHR functionality - while duly respecting all ethical and legal concerns - to reap full benefits of ML.

  • 124.
    Ashfaq, Awais
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. Halland Hospital, Region Halland, Sweden.
    Pinheiro Sant'Anna, Anita
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Lingman, Markus
    Halland Hospital, Region Halland, Sweden & Institute of Medicine, Dept. of Molecular and Clinical Medicine/Cardiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Readmission prediction using deep learning on electronic health records2019In: Journal of Biomedical Informatics, ISSN 1532-0464, E-ISSN 1532-0480, Vol. 97, article id 103256Article in journal (Refereed)
    Abstract [en]

    Unscheduled 30-day readmissions are a hallmark of Congestive Heart Failure (CHF) patients that pose significant health risks and escalate care cost. In order to reduce readmissions and curb the cost of care, it is important to initiate targeted intervention programs for patients at risk of readmission. This requires identifying high-risk patients at the time of discharge from hospital. Here, using real data from over 7,500 CHF patients hospitalized between 2012 and 2016 in Sweden, we built and tested a deep learning framework to predict 30-day unscheduled readmission. We present a cost-sensitive formulation of Long Short-Term Memory (LSTM) neural network using expert features and contextual embedding of clinical concepts. This study targets key elements of an Electronic Health Record (EHR) driven prediction model in a single framework: using both expert and machine derived features, incorporating sequential patterns and addressing the class imbalance problem. We show that the model with all key elements achieves a higher discrimination ability (AUC 0.77) compared to the rest. Additionally, we present a simple financial analysis to estimate annual savings if targeted interventions are offered to high risk patients. © 2019 The Authors

  • 125.
    Askfelt, Simone
    et al.
    Halmstad University, School of Information Technology.
    Arbenita, Osmani
    Halmstad University, School of Information Technology.
    Ekologiskt hållbar med Business Intelligence: Stöd från BI vid ekologiskt hållbart arbete2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Working ecologically sustainable is in some cases essential for a business to continue to be active on the market. There is a larger demand on businesses today to work ecologically sustainable. This has led to businesses reviewing the way they work in order to reduce their environmental impact. The demand on businesses to reduce their environmental impact has led to implementations of new systems with the purpose of supporting their ecological sustainability. A system that is able to support working with ecological sustainability is BI. With the support from BI, businesses can collect, store and analyze data and hence become more informed about how their processes affect the ecological sustainability. However, studies regarding the relationship between BI and ecological sustainability are few. In many cases businesses overview their work with ecological sustainability separate from remaining part of the business. The main purpose of the study is to identify and map how businesses work with ecological sustainability in practice with support from BI. This is mapped in order to finally compose and present proposals on how BI could strengthen the way businesses work with ecological sustainability. The empirical data for this study were collected through semi-structured interviews. The result of the study shows that manufacturing businesses do not take full support from BI regarding their work with ecological sustainability. The study presents proposals of how BI could strengthen businesses work with ecological sustainability

  • 126.
    Assabie Lake, Yaregal
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Multifont recognition System for Ethiopic Script2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, we present a general framework for multi-font, multi-size and multi-style Ethiopic character recognition system. We propose structural and syntactic techniques for recognition of Ethiopic characters where the graphically comnplex characters are represented by less complex primitive structures and their spatial interrelationships. For each Ethiopic character, the primitive structures and their spatial interrelationships form a unique set of patterns.

    The interrelationships of primitives are represented by a special tree structure which resembles a binary search tree in the sense that it groups child nodes as left and right, and keeps the spatial position of primitives in orderly manner. For a better computational efficiency, the primitive tree is converted into string pattern using in-order traversal, which generates a base of the alphabet that stores possibly occuring string patterns for each character. The recognition of characters is then achieved by matching the generated patterns with each pattern in a stored knowledge base of characters.

    Structural features are extracted using direction field tensor, which is also used for character segmentation. In general, the recognition system does not need size normalization, thinning or other preprocessing procedures. The only parameter that needs to be adjusted during the recognition process is the size of Gaussian window which should be chosen optimally in relation to font sizes. We also constructed an Ethiopic Document Image Database (EDIDB) from real life documents and the recognition system is tested with respect to variations in font type, size, style, document skewness and document type. Experimental results are reported.

  • 127.
    Assabie, Yaregal
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    A comprehensive Dataset for Ethiopic Handwriting Recognition2009In: Proceedings SSBA '09: Symposium on Image Analysis, Halmstad University, Halmstad, March 18-20, 2009 / [ed] Josef Bigun & Antanas Verikas, Halmstad: Halmstad University , 2009, p. 41-43Chapter in book (Other academic)
    Abstract [en]

    Ethiopic script is used by several languages in Ethiopia for writing. We present a comprehensive dataset of handwritten Ethiopic script called DEHR (Dataset for Ethiopic Handwriting Recognition) captured both offline and online. The offline dataset includes isolated characters, Ethiopian church documents and ordinary handwritten texts dealing with various real-life issues. The ordinary texts and isolated characters were freely written by several participants. The church documents are written in Geez and Amharic languages whereas the language for ordinary texts is Amharic only. The online dataset was collected by using two Digimemo devices of different sizes. For isolated characters and online dataset, all the 265 character samples used by Amharic language are included. The dataset is intended to set a benchmark for training and/or testing handwriting recognition, character and word segmentation, and text line detection. The dataset is can be accessed by contacting the authors or via http://www.hh.se/staff/josef/.

  • 128.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa, Ethiopia .
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    A Hybrid System for Robust Recognition of Ethiopic Script2007In: Ninth International Conference on Document Analysis and Recognition: proceedings : Curtiba, Paraná, Brazil, September 23-26, 2007 / [ed] IEEE Computer Society, Los Alamitos, Calif.: IEEE Computer Society, 2007, p. 556-560Conference paper (Refereed)
    Abstract [en]

    In real life, documents contain several font types, styles, and sizes. However, many character recognition systems show good results for specific type of documents and fail to produce satisfactory results for others. Over the past decades, various pattern recognition techniques have been applied with the aim to develop recognition systems insensitive to variations in the characteristics of documents. In this paper, we present a robust recognition system for Ethiopic script using a hybrid of classifiers. The complex structures of Ethiopic characters are structurally and syntactically analyzed, and represented as a pattern of simpler graphical units called primitives. The pattern is used for classification of characters using similarity-based matching and neural network classifier. The classification result is further refined by using template matching. A pair of directional filters is used for creating templates and extracting structural features. The recognition system is tested by real life documents and experimental results are reported.

  • 129.
    Assabie, Yaregal
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    A neural network approach for multifont and size-independent recognition of ethiopic characters2007In: Progress in pattern recognition / [ed] Singh, S, Singh, M, Springer London, 2007, p. 129-137Conference paper (Refereed)
    Abstract [en]

    Artificial neural networks are one of the most commonly used tools for character recognition problems, and usually they take gray values of 2D character images as inputs. In this paper, we propose a novel neural network classifier whose input is ID string patterns generated from the spatial relationships of primitive structures of Ethiopiccharacters. The spatial relationships of primitives are modeled by a special tree structure from which a unique set of string patterns are generated for each character. Training theneural network with string patterns of different font types and styles enables the classifier to handle variations in font types, sizes, and styles. We use a pair of directional filters forextracting primitives and their spatial relationships. The robustness of the proposed recognition system is tested by real life documents and experimental results are reported.

  • 130.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa, Ethiopia .
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Ethiopic Character Recognition Using Direction Field Tensor2006In: The 18th International Conference on Pattern Recognition: proceedings : 20-24 August, 2006, Hong Kong, Los Alamitos, Calif.: IEEE Computer Society, 2006, p. 284-287Conference paper (Refereed)
    Abstract [en]

    Many languages in Ethiopia use a unique alphabet called Ethiopic for writing. However, there is no OCR system developed to date. In an effort to develop automatic recognition of Ethiopic script, a novel system is designed by applying structural and syntactic techniques. The recognition system is developed by extracting primitive structural features and their spatial relationships. A special tree structure is used to represent the spatial relationship of primitive structures. For each character, a unique string pattern is generated from the tree and recognition is achieved by matching the string against a stored knowledge base of the alphabet. To implement the recognition system, we use direction field tensor as a tool for character segmentation, and extraction of structural features and their spatial relationships. Experimental results are reported.

  • 131.
    Assabie, Yaregal
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Ethiopic Document Image Database for Testing Character Recognition Systems2006Report (Other academic)
    Abstract [en]

    In this paper we describe the acquisition and content of a large database of Ethiopic documents for testing and evaluating character recognition systems. The Ethiopic Document Image Database (EDIDB) contains documents written in Amharic and Geez languages. The database was built from a variety of documents such as printouts, books, newspapers, and magazines. Documents written in various font types, sizes and styles were included in the database. Degraded and poor quality documents were also included in the database to represent the real life situation. A total of 1,204 pages were scanned at a resolution of 300 dpi and saved as grayscale images of JPEG format. We also describe an evaluation protocol for standardizing the comparison of recognition systems and their results. The database is made available to the research community through http://www.hh.se/staff/josef/.

  • 132.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa Ethiopia.
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    HMM-Based Handwritten Amharic Word Recognition with Feature Concatenation2009In: Proceedings of the International Conference on Document Analysis and Recognition, ICDAR, New York: IEEE Press, 2009, p. 961-965Conference paper (Refereed)
    Abstract [en]

    Amharic is the official language of Ethiopia and uses Ethiopic script for writing. In this paper, we present writer-independent HMM-based Amharic word recognition for offline handwritten text. The underlying units of the recognition system are a set of primitive strokes whose combinations form handwritten Ethiopic characters. For each character, possibly occurring sequences of primitive strokes and their spatial relationships, collectively termed as primitive structural features, are stored as feature list. Hidden Markov models for Amharic words are trained with such sequences of structural features of characters constituting words. The recognition phase does not require segmentation of characters but only requires text line detection and extraction of structural features in each text line. Text lines and primitive structural features are extracted by making use of direction field tensor. The performance of the recognition system is tested by a database of unconstrained handwritten documents collected from various sources.

  • 133.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa Ethiopia .
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Lexicon-based Offline Recognition of Amharic Words in Unconstrained Handwritten Text2008In: 19th International Conference on Pattern Recognition: (ICPR 2008) ; Tampa, Florida, USA 8-11 December 2008, New York: IEEE Computer Society, 2008, article id 4761145Conference paper (Refereed)
    Abstract [en]

    This paper describes an offline handwriting recognition system for Amharic words based on lexicon. The system computes direction fields of scanned handwritten documents, from which pseudo-characters are segmented. The pseudo-characters are organized based on their proximity and direction to form text lines. Words are then segmented by analyzing the relative gap between subsequent pseudocharacters in text lines. For each segmented word image, the structural characteristics of pseudo-characters are syntactically analyzed to predict a set of plausible characters forming the word. The most likelihood word is finally selected among candidates by matching against the lexicon. The system is tested by a database of unconstrained handwritten Amharic documents collected from various sources. The lexicon is prepared from words appearing in the collected database.

  • 134.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa, Ethiopia .
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Multifont size-resilient recognition system for Ethiopic script2007In: International Journal on Document Analysis and Recognition, ISSN 1433-2833, E-ISSN 1433-2825, Vol. 10, no 2, p. 85-100Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel framework for recognition of Ethiopic characters using structural and syntactic techniques. Graphically complex characters are represented by the spatial relationships of less complex primitives which form a unique set of patterns for each character. The spatial relationship is represented by a special tree structure which is also used to generate string patterns of primitives. Recognition is then achieved by matching the generated string pattern against each pattern in the alphabet knowledge-base built for this purpose. The recognition system tolerates variations on the parameters of characters like font type, size and style. Direction field tensor is used as a tool to extract structural features.

  • 135.
    Assabie, Yaregal
    et al.
    Department of Computer Science, Addis Ababa University, Ethiopia.
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent Systems´ laboratory.
    Offline handwritten Amharic word recognition2011In: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 32, no 8, p. 1089-1099Article in journal (Refereed)
    Abstract [en]

    This paper describes two approaches for Amharic word recognition in unconstrained handwritten text using HMMs. The first approach builds word models from concatenated features of constituent characters and in the second method HMMs of constituent characters are concatenated to form word model. In both cases, the features used for training and recognition are a set of primitive strokes and their spatial relationships. The recognition system does not require segmentation of characters but requires text line detection and extraction of structural features, which is done by making use of direction field tensor. The performance of the recognition system is tested by a dataset of unconstrained handwritten documents collected from various sources, and promising results are obtained. (C) 2011 Elsevier B.V. All rights reserved.

  • 136.
    Assabie, Yaregal
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Josef
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Offline Handwritten Amharic Word Recognition Using HMMs2009In: Proceedings SSBA '09: Symposium on Image Analysis, Halmstad University, Halmstad, March 18-20, 2009 / [ed] Josef Bigun & Antanas Verikas, Halmstad: Halmstad University , 2009, p. 89-92Chapter in book (Other academic)
    Abstract [en]

    This paper describes two appraches for Amharic word recognition in unconstrained handwritten text using HMMs. The first approach builds word models from concatenated features of constituent characters and in the second method HMMs of constituent characters are concatenated to form word model. In both cases, the features used for training and recognition are primitive strokes and their spatial relationships. The recognition system does not require segmentation of characters but requires text line detection and extraction of structural features, which is done by making use of direction field tensor. The performance of the recognition system is tested by DEHR dataset of unconstrained handwritten documents collected from various sources.

  • 137.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa, Ethiopia.
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Online Handwriting Recognition of Ethiopic Script2008In: Proceedings: Eleventh International Conference on Frontiers in Handwriting Recognition, Montréal, Québec - Canada, August 19-21, 2008 / [ed] Ching Y Suen, Montréal: CENPARMI, Concordia University , 2008, p. 153-158Conference paper (Refereed)
    Abstract [en]

    Online recognition of handwritten characters is gaining a renewed interest as it provides a natural way of data entry for a wide variety of handheld devices. In this paper, we present online handwriting recognition system for Ethiopic script based on the structural and syntactical analysis of the strokes forming characters. The complex structures of characters are represented by the spatio- temporal relationships of simple-shaped strokes called primitives. A special tree structure is used to model spatio- temporal relationships of the strokes. The tree generates a unique set of primitive stroke sequences for each character, and for recognition each stroke sequence is matched against a stored knowledge base. Characters are also classified based on their structural similarity to select a plausible set of characters for un unknown input, which improves recognition and processing time. We also present a dataset collected for training and testing online recognition systems for Ethiopic script. The dataset is prepared in accordance with the international standard UNIPEN format. The recognition system is tested with the collected dataset and experimental results are reported.

  • 138.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa, Ethiopia .
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Structural and Syntactic Techniques for Recognition of Ethiopic Characters2006In: Structural, syntactic, and statistical pattern recognition joint IAPR international workshops SSPR 2006 and SPR 2006, Hong Kong, China, August 17-19, 2006 : proceedings: Lecture Notes in Computer Sciences (Volume 4109/2006), Berlin: Springer Berlin/Heidelberg, 2006, p. 118-126Conference paper (Refereed)
    Abstract [en]

    OCR technology of Latin scripts is well advanced in comparison to other scripts. However, the available results from Latin are not always sufficient to directly adopt them for other scripts such as the Ethiopic script. In this paper, we propose a novel approach that uses structural and syntactic techniques for recognition of Ethiopic characters. We reveal that primitive structures and their spatial relationships form a unique set of patterns for each character. The relationships of primitives are represented by a special tree structure, which is also used to generate a pattern. A knowledge base of the alphabet that stores possibly occurring patterns for each character is built. Recognition is then achieved by matching the generated pattern against each pattern in the knowledge base. Structural features are extracted using direction field tensor. Experimental results are reported, and the recognition system is insensitive to variations on font types, sizes and styles.

  • 139.
    Assabie, Yaregal
    et al.
    Addis Ababa University, Department of Computer Science, Addis Ababa Ethiopia.
    Bigun, Josef
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Writer-independent Offline Recognition of Handwritten Ethiopic Characters2008In: Proceedings: Eleventh International Conference on Frontiers in Handwriting Recognition, Montréal, Québec - Canada, August 19-21, 2008 / [ed] Ching Y Suen, Montréal: CENPARMI, Concordia University , 2008, p. 652-657Conference paper (Refereed)
    Abstract [en]

    This paper presents writer-independent offline handwritten character recognition for Ethiopic script. The recognition is based on the characteristics of primitive strokes that make up characters. The spatial relationships of primitives whose combinations form complex structures of Ethiopic characters are used as a basis for recognition. Although this approach efficiently recognizes properly written characters, the recognition rate drops for characters where the spatial relationships of their primitives could not be drawn. This happens mostly when the connections between primitives are not properly written, which is a common case in handwriting. To complement the recognition, we classify characters based on the characteristics of their primitives, resulting in grouping of characters in a five-dimensional space. Once the type of characters is identified, recognition can be achieved with a minimal set of information from their spatial relationships. A comprehensive database is also developed to standardize the evaluation of research works on offline Ethiopic handwriting recognition systems. Our proposed system is tested is with the database and experimental results are reported.

  • 140.
    Assarsson, Fredrik
    et al.
    Halmstad University, School of Information Technology.
    Nilsson, Felix
    Halmstad University, School of Information Technology.
    Utredning av övertoners effekter på transformatorer2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is a study of how one of Halmstad Energi och Miljö Nät AB’s transformers is affected by current harmonics. The study is mostly about how much the transformer's nominal power must be derated. The study shows the theory of both what is harmonics, how harmonics affect transformers and calculation models for derating transformers. The methods used and compared for the transformer power write-down are factor K, which is described in SS-EN 50464-3 and K-factor, which is described in ANSI / IEEE C57.100.

    In order to realistically investigate how the different standards affect the transformer, three cases have been tested.

    • The mean effect of the harmonics over a month, based on collected measurement data.
    • The maximum effect of the harmonics over a month, based on collected measurement data.
    • The effects of harmonics if the harmonic levels increase in the future.

    The result of the study shows that in the cases based on measurement data the nominal power of the transformer should be reduced by about 6-17% for the K-factor method. For factor K, the figures are about 2.5-7.5%. However, the measurement data from all cases shows that the load rate of the tested transformer is far below the maximum impaired effect. If the amount of current harmonics would increase in the future, a write-down of 30% of the maximum effect is not unreasonable.

  • 141.
    Astviken, Sean
    Halmstad University, School of Information Technology.
    Moderna Hot och Risker:: IT-säkerhetsarkitektur för ett medelstort företag –utifrån ett perspektiv hos svenska sjukhus2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 142.
    Aujla, Gagangeet Singh
    et al.
    Thapar University, Patiala, India.
    Chaudhary, Rajat
    Thapar University, Patiala, India.
    Kumar, Neeraj
    Thapar University, Patiala, India.
    Rodrigues, Joel J. P. C.
    National Institute of Telecommunications (Inatel), Santa Rita do Sapucaí, Brazil; University of Beira Interior, Covilhã, Portugal; ITMO University, St. Petersburg, Russia; University of Fortaleza (Unifor), Fortaleza, Brazil.
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Data Offloading in 5G-Enabled Software-Defined Vehicular Networks: A Stackelberg-Game-Based Approach2017In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 55, no 8, p. 100-108Article in journal (Refereed)
    Abstract [en]

    Data offloading using vehicles is one of the most challenging tasks to perform due to the high mobility of vehicles. There are many solutions available for this purpose, but due to the inefficient management of data along with the control decisions, these solutions are not adequate to provide data offloading by making use of the available networks. Moreover, with the advent of 5G and related technologies, there is a need to cope with high speed and traffic congestion in the existing infrastructure used for data offloading. Hence, to make intelligent decisions for data offloading, an SDN-based scheme is presented in this article. In the proposed scheme, an SDNbased controller is designed that makes decisions for data offloading by using the priority manager and load balancer. Using these two managers in SDN-based controllers, traffic routing is managed efficiently even with an increase in the size of the network. Moreover, a single-leader multi-follower Stackelberg game for network selection is also used for data offloading. The proposed scheme is evaluated with respect to several parameters where its performance was found to be superior in comparison to the existing schemes. © Copyright 2017 IEEE

  • 143.
    Austli, Viktor
    et al.
    Halmstad University, School of Information Technology.
    Hernborg, Elin
    Halmstad University, School of Information Technology.
    Standardization of Bug Validation2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The usage of the Internet is widely implemented all over the world in a number of concepts. This generates a demand of establishing security as to sustain the integrity of data. In this thesis a service will be presented which can be used to identify various web vulnerabilities in order to regulate these and therefore prevent exploitation. As the world is today the increase of technical implementation provides with a growing amount of security flaws, this affect the organizations which may have to increase their resource financing in an effort to counter these. But what if a tremendous amount of work could be automated and avoid organizations having to spend an enormous amount of finances validating security flaws reported to them? What if these flaws could be validated in a more effective manner? With this tool being establish an individual will no longer require advanced technical knowledge in order to identify whether a web vulnerability is present or not but instead have an automated test perform the procedure for them.

  • 144.
    Axelsson, Andreas
    Halmstad University, School of Information Technology.
    Bluetoothsäkerhet, neglegerad eller (o)kunskap2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Under 2017 hittades sårbarheten Blueborne som gjorde att en person kunde ta sig in i mobiltelefoner eller datorer helt obemärkt genom att enheten endast ha igång bluetooth.

    Bluetoothsäkerheten behövs tas på minst lika stort allvar som alla andra enheter som tillexempel wifi eller annan trådlös utrustning som kan äventyra att information hamnar i orätta händer, för skulle felaktig information nå en person med ont uppsåt så skulle konsekvenserna vara förödande för privatpersoner eller för företag.

    Denna uppsats behandlar frågor genom att intervjua personer på företag och genom enkätundersökning, det har påvisats att majoriteten av företag har bristande kunskap eller saknar någonting som kan varna en användare eller administratör vid en attack. Diskussion kring attackers potentiella förödelse mot företag när det kommer kring information och drift och hur det går att skydda sig.

  • 145.
    Babich, M. V.
    et al.
    St. Petersburg Department of Steklov Mathematical Institute .
    Bordag, Ljudmila A.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Applied Mathematics and Physics (CAMP).
    Quasi periodic vortex structures in two-dimensional flows in an inviscid incompressible fluid2005In: Russian journal of mathematical physics, ISSN 1061-9208, E-ISSN 1555-6638, Vol. 12, no 2, p. 121-156Article in journal (Refereed)
    Abstract [en]

    We consider a two-dimensional steady motion of an inviscid incompressible fluid described by the equation &UDelta; u(x,y) = F(u(x,y)), where u(x,y) is the streamfunction, &UDelta; is the Laplace operator, and F((.)) an arbitrary function measuring the flow vorticity. Apparently, until now, the only way to treat an equation of the above type with nontrivial function F analytically is to use the algebro-geometric method for integrable equations. In particular, we investigate the Cosh-Laplace equation (ChL) &UDelta; u(x,y) = &PLUSMN; 4cosh(u(x,y)) by means of the special technique of finite-gap integration, which allows us to obtain real solutions of the ChL equation by using a Riemann surface with appropriate symmetry. We study the first nontrivial case corresponding to a Riemann surface of genus g = 3. The hydrodynamical interpretation of finite-gap solutions is meaningful, and we try to understand the fluid processes described by these solutions. To this end, we take a Riemann surface with additional symmetry properties. We present four five-parameter families of exact solutions. These solutions are given in terms of Jacobi elliptic functions, which enables us to directly investigate the relevant properties. We also find explicit formulas for the lines of singularity. It is of interest from the point of view of algebraic geometry that the structure of the theta divisor can be described.

  • 146.
    Bacauskiene, Marija
    et al.
    Department of Applied Electronics, Kaunas University of Technology, Studentu 50, LT-51368, Kaunas, Lithuania.
    Cibulskis, Vladas
    Department of Applied Electronics, Kaunas University of Technology, Studentu 50, LT-51368, Kaunas, Lithuania.
    Verikas, Antanas
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Selecting variables for neural network committees2006In: Advances in neural networks - ISNN 2006: third International Symposium on Neural Networks, Chengdu, China, May 28 - June 1, 2006 ; proceedings. I / [ed] Jun Wang, Berlin: Springer Berlin/Heidelberg, 2006, p. 837-842Conference paper (Refereed)
    Abstract [en]

    The aim of the variable selection is threefold: to reduce model complexity, to promote diversity of committee networks, and to find a trade-off between the accuracy and diversity of the networks. To achieve the goal, the steps of neural network training, aggregation, and elimination of irrelevant input variables are integrated based on the negative correlation learning [1] error function. Experimental tests performed on three real world problems have shown that statistically significant improvements in classification performance can be achieved from neural network committees trained according to the technique proposed.

  • 147.
    Bacauskiene, Marija
    et al.
    Kaunas University of Technology.
    Gelzinis, Adas
    Kaunas University of Technology.
    Kaseta, Marius
    Kaunas University of Medicine.
    Kovalenko, Marina
    Kaunas University of Technology.
    Pribuisiene, Ruta
    Kaunas University of Medicine.
    Uloza, Virgilijus
    Kaunas University of Medicine.
    Verikas, Antanas
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Intelligent systems (IS-lab).
    Multiple feature sets and genetic search based discrimination of pathological voices2007In: Proceedings of the International ConferenceModels and Analysis of Vocal Emissions for Biomedical Applications”, MAVEBA, 2007, p. 195-198Conference paper (Refereed)
  • 148.
    Bacauskiene, Marija
    et al.
    Department of Applied Electronics, Kaunas University of Technology LT-3031, Kaunas, Lithuania.
    Verikas, Antanas
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Selecting salient features for classification based on neural network committees2004In: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 25, no 16, p. 1879-1891Article in journal (Refereed)
    Abstract [en]

    Aggregating outputs of multiple classifiers into a committee decision is one of the most important techniques for improving classification accuracy. The issue of selecting an optimal subset of relevant features plays also an important role in successful design of a pattern recognition system. In this paper, we present a neural network based approach for identifying salient features for classification in neural network committees. Feature selection is based on two criteria, namely the reaction of the cross-validation data set classification error due to the removal of the individual features and the diversity of neural networks comprising the committee. The algorithm developed removed a large number of features from the original data sets without reducing the classification accuracy of the committees. The accuracy of the committees utilizing the reduced feature sets was higher than those exploiting all the original features.

  • 149.
    Bacauskiene, Marija
    et al.
    Department of Applied Electronics, Kaunas University of Technology, LT-3031, Kaunas, Lithuania.
    Verikas, Antanas
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    The Evidence Theory Based Post-Processing of Colour Images2004In: Informatica (Vilnius), ISSN 0868-4952, E-ISSN 1822-8844, Vol. 15, no 3, p. 315-328Article in journal (Refereed)
    Abstract [en]

    The problem of post-processing of a classified image is addressed from the point of view of the Dempster-Shafer theory of evidence. Each neighbour of a pixel being analyzed is considered as an item of evidence supporting particular hypotheses regarding the class label of that pixel. The strength of support is defined as a function of the degree of uncertainty in class label of the neighbour, and the distance between the neighbour and the pixel being considered. A post-processing window defines the neighbours. Basic belief masses are obtained for each of the neighbours and aggregated according to the rule of orthogonal sum. The final label of the pixel is chosen according to the maximum of the belief function.

  • 150.
    Bacauskiene, Marija
    et al.
    Department of Applied Electronics, Kaunas University of Technology, Lithuania .
    Verikas, Antanas
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Gelzinis, Adas
    Department of Applied Electronics, Kaunas University of Technology, Lithuania .
    Valincius, Donatas
    Department of Applied Electronics, Kaunas University of Technology, Lithuania .
    A feature selection technique for generation of classification committees and its application to categorization of laryngeal images2009In: Pattern Recognition, ISSN 0031-3203, E-ISSN 1873-5142, Vol. 42, no 5, p. 645-654Article in journal (Refereed)
    Abstract [en]

    This paper is concerned with a two phase procedure to select salient features (variables) for classification committees. Both filter and wrapper approaches to feature selection are combined in this work. In the first phase, definitely redundant features are eliminated based on the paired t-test. The test compares the saliency of the candidate and the noise features. In the second phase, the genetic search is employed. The search integrates the steps of training, aggregation of committee members, selection of hyper-parameters, and selection of salient features into the same learning process. A small number of genetic iterations needed to find a solution is the characteristic feature of the genetic search procedure developed. The experimental tests performed on five real-world problems have shown that significant improvements in Classification accuracy can be obtained in a small number of iterations if compared to the case of using all the features available.

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