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  • 1.
    Abbas, Taimoor
    et al.
    Lund Univ, Elect & Informat Technol Dept, S-22100 Lund, Sweden..
    Sjöberg, Katrin
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Kåredal, Johan
    Lund Univ, Elect & Informat Technol Dept, S-22100 Lund, Sweden..
    Tufvesson, Fredrik
    Lund Univ, Elect & Informat Technol Dept, S-22100 Lund, Sweden..
    A Measurement Based Shadow Fading Model for Vehicle-to-Vehicle Network Simulations2015In: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, article id 190607Article in journal (Refereed)
    Abstract [en]

    The vehicle-to-vehicle (V2V) propagation channel has significant implications on the design and performance of novel communication protocols for vehicular ad hoc networks (VANETs). Extensive research efforts have been made to develop V2V channel models to be implemented in advanced VANET system simulators for performance evaluation. The impact of shadowing caused by other vehicles has, however, largely been neglected in most of the models, as well as in the system simulations. In this paper we present a shadow fading model targeting system simulations based on real measurements performed in urban and highway scenarios. The measurement data is separated into three categories, line-of-sight (LOS), obstructed line-of-sight (OLOS) by vehicles, and non-line-of-sight due to buildings, with the help of video information recorded during the measurements. It is observed that vehicles obstructing the LOS induce an additional average attenuation of about 10 dB in the received signal power. An approach to incorporate the LOS/OLOS model into existing VANET simulators is also provided. Finally, system level VANET simulation results are presented, showing the difference between the LOS/OLOS model and a channel model based on Nakagami-m fading.

  • 2.
    Abboud, Mohamad Moulham
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Simulation of 3ph induction motor in Matlab with VVVF starting method2016Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Nowadays, three-phase induction motors are widely used on industrial and other types of processes. Therefore, accurate knowledge of an induction motor performance is very essential to have an idea of its operation conditions. This study is a sequel of a previous one, where Direct and Soft starting methods of three-phase motors has been simulated and compared. As in the previous study, the theory behind this one is based on representing the real motor by aset of equations and values in Matlab, forming a corresponding idealistic motor in a way where all the physical effects are similar. The motor is started under three different frequencies in the VVVF method using supporting simulation of the current, torque, speed,efficiency and power factor curves. The results of the three starting methods are then discussed and compared.

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  • 3.
    Abdulrazzak, Shahm
    et al.
    Halmstad University, School of Information Technology.
    Mattsson, Tor
    Halmstad University, School of Information Technology.
    Java Auto Grader2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The process of grading code submissions in programming courses is time-consuming and error-prone. To address this issue, we propose a project that automates the testing and grading process for Java code submissions at Halmstad University. Our approach leverages property-based testing using the JUnit Quick-Check library to generate tests and test reports automatically.

     

    The tool we demonstrate in this project is designed to provide students with immediate feedback on their code submissions and reduce the workload for instructors. By automatically generating tests and test reports, our approach ensures that code submissions meet the required specifications and are free from common errors. The com.pholser library is utilized to implement the property-based testing approach.

     

    We believe that our project has the potential to improve the grading process for programming courses and provide a more efficient and effective way of assessing student code submissions. Our implementation can be easily extended to support other programming languages and can be integrated with existing learning management systems to provide a seamless experience for instructors and students alike.

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  • 4.
    Abika, Collins
    Halmstad University, School of Information Technology.
    Complaint system for Health Care Center Hjärtat2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today the IT support could be overwhelmed with loads of requests from the clients within the Health care center Hjärtat (Also known as HCCH) through email, which is an inefficient way to store and manage information of each complaint. Tracking down the list of requests is also an issue. For the goals to ensure the achievements of expanding to new clients, IT support needs a better alternative way to manage, store, and retrieve information. This thesis reports a prototype of a complaint management system implemented for the Healthcare center Helsingborg Hjärtat. The software architect pattern in this project is Model view control and applied on the Visual studio .Net core with the programming language of C-sharp and HTML. Test results showcase the prototype of the complaint management system as an administrator, and the result of the system handles the complaint cases well. The IT support experience keeps track of the complaints more efficiently sent from the client users.

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  • 5.
    Aboelwafa, Mariam M. N.
    et al.
    Electronics and Communications Engineering Department, American University in Cairo, New Cairo, Egypt.
    Seddik, Karim G.
    Electronics and Communications Engineering Department, American University in Cairo, New Cairo, Egypt.
    Eldefrawy, Mohamed Hamdy
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Gadallah, Yasser
    Electronics and Communications Engineering Department, American University in Cairo, New Cairo, Egypt.
    Gidlund, Mikael
    Department of Information Systems and Technology, Mid Sweden University, Sundsvall, Sweden.
    A Machine-Learning-Based Technique for False Data Injection Attacks Detection in Industrial IoT2020In: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 7, no 9, p. 8462-8471Article in journal (Refereed)
    Abstract [en]

    The accelerated move toward the adoption of the Industrial Internet-of-Things (IIoT) paradigm has resulted in numerous shortcomings as far as security is concerned. One of the IIoT affecting critical security threats is what is termed as the false data injection (FDI) attack. The FDI attacks aim to mislead the industrial platforms by falsifying their sensor measurements. FDI attacks have successfully overcome the classical threat detection approaches. In this article, we present a novel method of FDI attack detection using autoencoders (AEs). We exploit the sensor data correlation in time and space, which in turn can help identify the falsified data. Moreover, the falsified data are cleaned using the denoising AEs (DAEs). Performance evaluation proves the success of our technique in detecting FDI attacks. It also significantly outperforms a support vector machine (SVM)-based approach used for the same purpose. The DAE data cleaning algorithm is also shown to be very effective in recovering clean data from corrupted (attacked) data. © 2014 IEEE.

  • 6.
    Abramson, Norman
    et al.
    Department of Electrical Engineering, University of Hawaii, USA.
    Sacchi, Claudio
    Information Engineering and Computer Science Department, University of Trento, Italy.
    Bellalta, Boris
    Department of Information and Communication Technologies, Universitat Pompeu Fabra, Spain.
    Vinel, Alexey
    Saint-Petersburg Institute for Informatics and Automation, Russian Academy of Sciences, Russia.
    Multiple access communications in future-generation wireless networks2012In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, p. Art nr 45-Article in journal (Refereed)
  • 7.
    Abuella, Mohamed
    et al.
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Atoui, M. Amine
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Nowaczyk, Sławomir
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Johansson, Simon
    CetaSol AB, Gothenburg, Sweden.
    Faghani, Ethan
    CetaSol AB, Gothenburg, Sweden.
    Data-Driven Explainable Artificial Intelligence for Energy Efficiency in Short-Sea Shipping2023In: Machine Learning and Knowledge Discovery in Databases: Applied Data Science and Demo Track: European Conference, ECML PKDD 2023, Turin, Italy, September 18–22, 2023, Proceedings, Part VII / [ed] Gianmarco De Francisci Morales; Claudia Perlich; Natali Ruchansky; Nicolas Kourtellis; Elena Baralis; Francesco Bonchi, Cham: Springer, 2023, Vol. 14175, p. 226-241Conference paper (Refereed)
    Abstract [en]

    The maritime industry is under pressure to increase energy efficiency for climate change mitigation. Navigational data, combining vessel operational and environmental measurements from onboard instruments and external sources, are critical for achieving this goal. Short-sea shipping presents a unique challenge due to the significant influence of surrounding landscape characteristics. With high-resolution onboard data increasingly accessible through IoT devices, appropriate data representations and AI/ML analytical tools are needed for effective decision support. The aim of this study is to investigate the fuel consumption estimation model’s role in developing an energy efficiency decision support tool. ML models that lacking explainability may neglect important factors and essential constraints, such as the need to meet arrival time requirements. Onboard weather measurements are compared to external forecasts, and our findings demonstrate the necessity of eXplainable Artificial Intelligence (XAI) techniques for effective decision support. Real-world data from a short-sea passenger vessel in southern Sweden, consisting of 1754 voyages over 15 months (More of data description and code sources of this study can be found in the GitHub repository at https://github.com/MohamedAbuella/ST4EESSS), are used to support our conclusions.  © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

  • 8.
    Ackermann, Max
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Håkansson, Kevin
    Halmstad University, School of Business, Engineering and Science.
    Den generativa dämparen2020Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    It becomes more common with hybrid and electric vehicles around the world and in Sweden. These cars are becoming more and more effective with new sources of regenerative power such as the engine break. This prolongs the cars range which is making electric vehicles more and more competitive. So what is the next step when it comes to reusage of already used electricity? Is there more electric energy that we can reuse to help power the car? Each car has four dampers that absorbs momentum and converts it to thermal energy so that they can dampen its spring. If instead this movement would be turned into elektricenergy it could be stored to the battery or used by the car directly, just like the electric energy generated from the engine brake. The cars would be even more effective and get an even longer range. “Den generativa dämparen” will take advantage of this energy so it won’t go to waste. “Den generative dämparen” will dampen the springs momentum with induction charging. If this implementation succeeds in hybrid and electric cars big savings can be made. It’s estimated that Sweden, with this damper, can save 170 GWh each year in 2030.

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  • 9.
    Adekolu, Adekunle Matthew
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Khan, Hasan
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Neelam, Neelam
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Network Monitoring2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Managing a network is a very big functional area along with performance, devicemaintenance, security, performance, monitoring, troubleshooting, plan of changeand etc. Among all of these monitoring plays a vital role. It can cover a wide area ofnetwork management. Monitoring is the only way to find out whether the networkis functioning according to plan. In order to know what is happening in a network,how its functioning at any given time, a network should have a logging system. Nowa day this logging activity is done by Network monitoring tool. It lets user know thestatus of the network at any given time. This logging can give the user a wide viewwhat can't be seen in general. For example the statistics of a week or month, even ayear. Monitoring is a very important issue in an organization network which aroseover the time.In this project we are going to implement some well known network monitoringtools in a real world scenario and we will investigate how this monitoring tool canhelp network administrators to monitor a network . Moreover, what kind ofinformation we can extract from a network by these tools.The purpose of this project is to get an overall idea about the importance of networkmonitoring and what are the facts need to be considered while monitoring anetwork. There are lots of pros and cons in monitoring a network. So choosing theappropriate tool for monitoring is very important. Monitoring a network with theleast effects on network performance is the best solution in case of monitoring.The outcome from these monitoring tools is a wide range of useful data andintegration of these data produces the status of the network at any give time.Moreover these data will be logged to create a statistical report. Different users suchas a network admin and organization can use this information from differentperspectives to make a network more efficient for users.

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  • 10.
    Adnan Abdu, Jihad
    et al.
    Halmstad University, School of Information Technology.
    Lundström, Philip
    Halmstad University, School of Information Technology.
    Water Quality Device: Testing Through Electronic Measurements2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Water is the source of all life, but unfortunately, the water quality is getting only worse due to many factors like overuse, contamination, indifference and even by nature itself. By identifying the problem, we are one step closer to solving the problem, and that is why an intelligent water quality device is required to examine water and detect impurities within it. In this project, we are developing a device that uses an entirely new method to measure water quality. Even though the theory behind the device is very advanced, the device is still primitive in its functions and needs development to increase the usefulness and accuracy of the measurements!

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  • 11.
    Ads, Khaled
    Halmstad University, School of Information Technology.
    Field uniformity and isotropy investigation of Halmstad University's reverberation chamber: In collaboration with Halmstad University and Ericsson AB, Lund2020Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is the final module of the Master's program in Electronics Design at Halmstad University. The Master Thesis work is a part of an ongoing development of Halmstad University's reverberation chamber (RC), which is aimed at frequencies in the low GHz range. The development process has been passing in several phases. One phase is to design a mechanical stirrer system which was done by the work presented in another thesis work. The current phase, which is done by this thesis work, is to investigate electromagnetic field uniformity and isotropy while using tuned-mode (stepped stirrer). The frequency 2.4 GHz was chosen because, from one hand, it fits the capability of the assigned equipment for this thesis (spectrum analyzer, signal generator, antennas). On the other hand, it is the operating frequency of a wide range of WIFI and BlueTooth devices that need to be tested inside the RC to comply with the Electromagnetic Compatibility (EMC) standards. The measurement results verified, to a reasonable extent, the field uniformity and isotropy. The standard deviation of all measurements, taken from different eight positions with three different orientations of the receiving antenna, was 1.5dB. It is less than 3dB fulfilling the IEC 61000-4-21standards for frequencies above 400MGHz. Moreover, a quality factor degradation test was conducted, showing a 3.5 dB reduction of the received power when the chamber was loaded by organic material. The received power, while sweeping the bandwidth 800MHz-1.5GHz, was measured. These results indicate that at the resonance frequencies of the chamber, the received power is higher than that at non-resonance frequencies.

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  • 12.
    Aein, Mohamad Javad
    et al.
    Department for Computational Neuroscience at the Bernstein Center Göttingen (Inst. of Physics 3) & Leibniz Science Campus for Primate Cognition, Georg-August-Universität Göttingen, Göttingen, Germany.
    Aksoy, Eren
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Wörgötter, Florentin
    Department for Computational Neuroscience at the Bernstein Center Göttingen (Inst. of Physics 3) & Leibniz Science Campus for Primate Cognition, Georg-August-Universität Göttingen, Göttingen, Germany.
    Library of actions: Implementing a generic robot execution framework by using manipulation action semantics2019In: The international journal of robotics research, ISSN 0278-3649, E-ISSN 1741-3176, Vol. 38, no 8, p. 910-934Article in journal (Refereed)
    Abstract [en]

    Drive-thru-Internet is a scenario in cooperative intelligent transportation systems (C-ITSs), where a road-side unit (RSU) provides multimedia services to vehicles that pass by. Performance of the drive-thru-Internet depends on various factors, including data traffic intensity, vehicle traffic density, and radio-link quality within the coverage area of the RSU, and must be evaluated at the stage of system design in order to fulfill the quality-of-service requirements of the customers in C-ITS. In this paper, we present an analytical framework that models downlink traffic in a drive-thru-Internet scenario by means of a multidimensional Markov process: the packet arrivals in the RSU buffer constitute Poisson processes and the transmission times are exponentially distributed. Taking into account the state space explosion problem associated with multidimensional Markov processes, we use iterative perturbation techniques to calculate the stationary distribution of the Markov chain. Our numerical results reveal that the proposed approach yields accurate estimates of various performance metrics, such as the mean queue content and the mean packet delay for a wide range of workloads. © 2019 IEEE.

  • 13.
    Afram, Abboud
    et al.
    Halmstad University, School of Information Technology.
    Sarab Fard Sabet, Danial
    Halmstad University, School of Information Technology.
    Company Intranet2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many companies use intranets where only authorized personnel can share, create, and access news, events, and knowledge in a company. An intranet is a web application with dynamic content. It consists of various functions and features that facilitate the information management and knowledge flow within the company. The main goal of this project is to create and design an intranet demo that is adaptable and extendable by companies and organizations. The intranet contains various primary functions that users can interact with. The designed intranet is based on the EPiServer Content Management System framework and is programmed in back-end and front-end with the Visual Studio IDE tool. The back- end part is mainly programmed in C# language to create functions and logic such as the intranet structure and then linked to the front-end part where the HTML, CSS, and JavaScript library React is used to encode the front-end and get a user interface. The finalized intranet contains various primary functions where authorized employees have individual profiles with their status and contact information. Users can share corporate events and access corporate news.

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  • 14.
    Aftab, Mohammad Adnan
    Halmstad University, School of Business, Engineering and Science.
    Biofuel, An alternative source for jet fuel in Aviation2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The transport industry is one of the fastest growing industries with the sector playing a significant role in negative impact on global warming and pollution through the emission of greenhouse gases. Aviation in particular, has enjoyed growth especially in the few decades. New airlines and aircraft manufacturers are coming up with different innovations and technologies to ensure they make the best possible environmentally friendly aircraft. The new main area of focus has been on how to come up with fuel that will reduce the greenhouse gas-emissions. The stakeholders in the same effort include developed nations like the United States, United Kingdom, Russia, France, Germany, and Canada among others. Energy providers as well as jet fuel suppliers are also making efforts to conserve the environment. The purpose of this thesis is to explore the area of biofuel in aviation by looking into various stakeholders involved in the efforts of the transition from fossil fuel to biofuel. The conclusion of this thesis is that biofuels are viable options in the aviation industries since there have been positive results in the tests made. 

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  • 15.
    Afzal, Wahaj
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    A Rule-based approach for detection of spatial object relations in images2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Deep learning and Computer vision are becoming a part of everyday objects and machines. Involvement of artificial intelligence in human’s daily life open doors to new opportunities and research. This involvement provides the idea of improving upon the in-hand research of spatial relations and coming up with a more generic and robust algorithm that provides us with 2-D and 3-D spatial relations and uses RGB and RGB-D images which can help us with few complex relations such as ‘on’ or ‘in’ as well. Suggested methods are tested on the dataset with animated and real objects, where the number of objects varies in every image from at least 4 to at most 10 objects. The size and orientation of objects are also different in every image.  

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  • 16.
    Agelis, Sacki
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Reconfigurable Optical Interconnection Networks for High-Performance Embedded2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In embedded computer and communication system the capacity demand for interconnection networks is increasing continuously in order to achieve high-performance systems. Recent breakthroughs show that by using reconfigurability inside a single chip substantial performance gains can be added. However, in this thesis the focus is on system level reconfigurability (between chips or modules) and the performance gains that potentially can be achieved by having support for runtime reconfigurability on the system level.This thesis addresses the field of runtime system level reconfigurability with the use of optics in switches and routers for data- and telecommunications, and in multi-processor systems used for embedded signal processing. Several reconfigurable systems for switching and routing with support to adapt for asymmetric traffic patterns are proposed and compared to identify how design choices affect flexibility, performance etc. The proposed solutions are characterized by their multistage optical interconnection networks with reconfigurable shuffle patterns, where the reconfigurability is provided by micro-optical-electrical mechanical systems. More specifically, application-specific bottlenecks can be resolved by reconfiguring the interconnection network according to the current application demands. The benefits of the architectural solutions are confirmed by simulations that clearly show that the architectures can achieve high performance for both symmetric application characteristics and for several classes of asymmetric application characteristics. The final architectural solution is characterized by electronic packet-switches interconnected through an optical backplane, which is reconfigurable. Moreover, the thesis presents how several signal processing applications can be mapped to run concurrently in a time-shared scheme on a single reconfigurable multi-processor system that has high flexibility to adapt for the application currently at hand. The interconnection network is then adapted (reconfigured) according to the demands of the currently executed application in each time instance. The analysis shows that it is feasible to build such a system with today’s components.

  • 17.
    Agelis, Sacki
    et al.
    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).
    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).
    Reconfigurable optical interconnection system supporting concurrent application-specific parallel computing2005In: 17th Symposium on Computer Architecture and High Performance Computing: SBAC-PAD 2005 : proceedings : 24-27 October, 2005, Rio de Janeiro, PR, Brazil / [ed] Claudio L. Amorim, Washington, DC, USA: IEEE Computer Society, 2005, p. 44-51Conference paper (Refereed)
    Abstract [en]

    Application specific architectures are highly desirable in embedded parallel computing systems at the same time as designers strive for using one embedded parallel computing platform for several applications. If this can be achieved, the cost can be decreased in comparison to using several different embedded parallel computing systems. This paper presents a novel approach of running several high-performance applications concurrently on one single parallel computing system. By using a reconfigurable backplane interconnection system, the applications can be run efficiently with high network flexibility since the interconnect network can be adapted to fit the application that is being processed for the moment. More precisely, this paper investigates how the space time adaptive processing (STAP) radar algorithm and the stripmap synthetic aperture radar (SAR) algorithm can be mapped on a multi-cluster processing system with a reconfigurable optical interconnection system realized by a micro-optical-electrical mechanical system (MOEMS) crossbars. The paper describes the reconfigurable platform, the two algorithms and how they individually can be mapped on the targeted multiprocessor system. It is also described how these two applications can be mapped simultaneously on the optical reconfigurable platform. Implications and requirements on communication bandwidth and processor performance in different critical points of the two applications are presented. The results of the analysis show that an implementation is feasible with today's MOEMS technology, and that the two applications can be successfully run in a time-sharing scheme, both at the processing side and at the access for interconnection bandwidth.

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  • 18.
    Agelis, Sacki
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    System-Level Runtime Reconfigurablity - Optical Interconnection Networks for Switching Applications2004In: Proceedings of the International Conference on Engineering of Reconfigurable Systems and Algorithms, ERSA'04 / [ed] Toomas P Plaks & M Gokhale, Athens, USA: CSREA Press, 2004, p. 155-162Conference paper (Refereed)
    Abstract [en]

    The performance requirements on data and telecommunication switches and routers are continuously increasing and it is evident that new ideas and architectures must come to light to satisfy these new demands. In this paper, a runtime reconfigurable modular design approach is presented, using state-of-the-art microoptical-electrical mechanical system (MOEMS) components. The paper introduces a novel field of reconfigurability, where reconfiguration is made on the system level instead of, e.g. fine-granularity reconfigurable logic. Different reconfigurable system solutions with support to adapt for asymmetric traffic patterns are proposed and compared to see how design choices affect flexibility, performance etc. The proposed solutions are characterized by their multistage networks with reconfigurable shuffle patterns.

  • 19.
    Agelis, Sacki
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Visualizing the Potential of Reconfigurable Shuffle-Patterns in Optoelectronic Routers by the Use of MOEMS2004In: Proceedings of the IASTED International Conference Communication Systems and Networks / [ed] Salvador C.E.P., Calgary, Canada: ACTA Press, 2004, p. 148-154Conference paper (Refereed)
    Abstract [en]

    A reconfigurable high performance multistage router architecture is presented and simulated. The router backbone network is an optical shuffle exchange network that has the power of reconfigurability through the use of micro-optical-electrical mechanical systems (MOEMS). The router is subjected to different application classes. The application classes have different characteristics in terms of symmetric/asymmetric traffic properties. We compare our reconfigurable shuffle-pattern for all three application classes for the specified router architecture.

  • 20.
    Agnoletto, Daniel
    et al.
    Institute of Informatics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Pignaton de Freitas, Edison
    Institute of Informatics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Time slot transmission scheme with packet prioritization for Bluetooth low energy devices used in real-time applications2020In: International Journal of Wireless Information Networks, ISSN 1068-9605, E-ISSN 1572-8129, Vol. 27, no 4, p. 518-534Article in journal (Refereed)
    Abstract [en]

    Bluetooth Low Energy (BLE) is one of the most important technologies that feed the growing field of Internet of Things and Wireless Sensor Networks. Due to its flexibility and unique low power-consumption, an increasing number of industrial devices, household appliances and wearables are being designed using it. However, the real-time demands of these networks such as timing and Quality of Service are not fully covered by the protocol itself. To help improve and offer some control over these characteristics, this paper presents a time slot transmission scheme with packet prioritization. It is based on the division and allocation of the connection interval to two types of messages: real-time and ordinary. The goal is to offer the lowest packet loss and time guarantees for real-time messages, while providing acceptable throughput for ordinary ones. Since the probability of a BLE connection to close increases with the number of packets sent through it, the position where a real-time packet is being sent as well as the number of ordinary messages in a connection represent key factors. The use of the first and last slot for real-time packets with ordinary flow restricted to the space between them decreases the transmission delay uncertainty and allows probability tuning based on the number of ordinary messages. Simulations were performed using the proposed scheme and a reduction of more than 100 times in the delay variance was observed for real-time transmissions. Regarding reliability, around 5% of the packets were lost for a bit error rate of 10−3. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

  • 21.
    Ahlbäck, David
    Halmstad University, School of Business, Engineering and Science.
    KONCEPTANALYS OCH DRIFTFALLSOPTIMERING AV "FREEPOWER – SOLAR BOAT"2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report aims to analyse the concept of Bjurtech AB:s ongoing development project “Freepower - Solar Boat”. Main focuses are technical optimization and usability from an end user perspective. Bjurtechs idea is to build an electric-powered 5-meter boat charged by integrated photovoltaic cells. The project´s intended pilot market is Sri Lankas coastal fishing fleet. A version for the Scandinavian market is also under consideration and both concepts are analysed in this report. Initially a 4.5-meter prototype was built and tested to try the concept in practise. Methods used are computer simulations in Matlab based on data collected from trail runs with the prototype combined with weather data from Sri Lanka and Sweden. The data and simulations were then used to try to determine whether the concept works for the intended target markets, as well as how the assumed user profiles affect usability and technical deterioration such as battery life. The approach used was to try to determine how to maximize the availability of the system in regards to battery charge level over the whole year at the same time as maximizing distance and boat speed per day. The systems CO2 emissions were then compared to an equivalent petrol-powered boat with the same amount of running hours over 25 years. The main findings of the study are, provided 12 to 14.5 nautical miles is regarded as a sufficient daily distance at 3 to 3.7 knots boat speed, that the system can deliver a high level of availability all year around for fishing operations in Sri Lanka. Considering the demand for daily availability is not as high for the assumed recreational use in Scandinavian markets the system is deemed to perform at a satisfactory level at these latitudes as well. The CO2 comparison showed a significant emissions decrease in the case of year around operations in Sri Lanka. In Scandinavia a reduction is obtained if there are a sufficient amount of operating hours per year. An increase of the installed rated power, Wp, was found to be the most cost efficient way of improving overall performance and that the prototypes photovoltaics of 580 Wp should in both the Sri Lankan and Scandinavian case be increased to a minimum of 800 Wp. Finally it was concluded that user awareness of how system operation impacts battery life can be of significant importance for a positive environmental result and long technical lifetime.

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  • 22.
    Ahlbäck, Joel
    et al.
    Halmstad University, School of Information Technology.
    Jalking, Jesper
    Halmstad University, School of Information Technology.
    Logistikföretag i försörjningskedjan: Rekommendationer till logistikföretag i hanteringen av informationssäkerhet2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Information security is an important aspect when running a business. Before, information security has been separated to the business area of IT. But lately this issue has broadened and become an important part of business-activity. This has resulted in a growing interest among business leaders. Literature within the subject information security mainly focuses on how organizations maintain safe systems and protect themselves from cyber-attacks and information infringements. Existing literature identifies new security threats that have emerged after advances in internet technology, but little is known about how these threats can be managed. Researchers request research on how cooperation in supply chains poses risks to secure information management. Logistics companies provide customers with logistics services such as warehouse management, transport, order processing and packaging. Logistics companies are a central node in supply chains. They often participate in several supply chains in different industries. The extensive interconnection of companies poses a security risk. It also means that logistics companies can be seen as targets for cyber-attacks. The purpose of the study has therefore been to create an understanding of the challenges logistics companies face in managing information security in the supply chain.

     

    The research question has been answered by interviewing representatives from logistics organizations. The empirical data has undergone a thematic analysis. The results of the study show that the management of information security varies between companies. The study’s conclusions present recommendations. The recommendations describe how logistics companies can manage information security in the supply chain.

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  • 23.
    Ahlstrand, Roland
    Halmstad University, School of Business and Engineering (SET), Centre for Innovation, Entrepreneurship and Learning Research (CIEL), Regional Learning and Governance (RELL).
    Social responsibility in connection with business closures: A study of closures of Ericsson Telecom facilities in Norrköping and Linköping2010In: Economic and Industrial Democracy, ISSN 0143-831X, E-ISSN 1461-7099, Vol. 31, no 4, p. 537-555Article in journal (Refereed)
    Abstract [en]

    The present article analyses why and how Ericsson Telecom assumeda greater responsibility than was legally required when it dismissedmore than 23,000 employees in Sweden at the beginning of the21st century. The analysis starts from neoinstitutional theoryand is based on case studies of the company’s closuresin Norrköping and Linköping. The article focuses,in particular, on the interaction between Ericsson, the tradeunions, the County Administrative Board, the County Labour Board,the Public Employment Service, the Swedish Employment SecurityCouncil, the government and the respective municipalities. Itis shown that the greater responsibility taken by Ericsson wasbased on its desire to maintain legitimacy by taking into considerationprevailing societal expectations regarding the company’sbehaviour.

  • 24.
    Ahmadi, Lina
    Halmstad University, School of Information Technology.
    Green Driving Application: Eco Driving2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Eco-driving has acquired great importance in recent years because it is a way to reduce energy consumption that can be applied to any type of vehicle. However, for these rules to be applied requires a process of continuous learning and motivation. For this reason many eco-driving assistants have emerged.

    This paper presents Green Driving, a driver safety app for Android that detects inattentive driving behaviors and gives corresponding feedback to drivers, scoring their driving and alerting them in case their behaviors are unsafe.  It’s about changing a person’s driving behavior by providing some kind of advice to the driver.  I have worked on an algorithm that is meant to reduce the fuel consumption of users. The algorithm is deployed in an android application.

    This application “Green Driving” is aimed at users with cars. It is basically like an assistant, suggesting the user when he should make the right gear changes, when to increase/decrease speed and avoids hard braking and rapid acceleration and etc. It is in order to drive economically, ecologic and in turn save money and safety. This is a smart way of letting a user drive economically and ecologic since almost everyone has an Android smartphone now. 

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  • 25.
    Ahmed, Rizwan
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Abbas, Shahid
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Electrical and Optical Characteristics of InP Nanowires based p-i-n Photodetectors2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Photodetectors are a kind of semiconductor devices that convert incoming light to an electrical signal. Photodetectors are classified based on their different structure, fabrication technology, applications and different sensitivity. Infrared photodetectors are widely used in many applications such as night vision, thermal cameras, remote temperature sensing, and medical diagnosis etc.

     

    All detectors have material inside that is sensitive to incoming light. It will absorb the photons and, if the incoming photons have enough energy, electrons will be excited to higher energy levels and if these electrons are free to move, under the effect of an external electric field, a photocurrent is generated.

     

    In this project Fourier Transform Infrared (FT-IR) Spectroscopy is used to investigate a new kind of photodiodes that are based on self-assembled semiconductor nanowires (NWs) which are grown directly on the substrate without any epi-layer. The spectrally resolved photocurrent (at different applied biases) and IV curves (in darkness and illumination) for different temperatures have been studied respectively. Polarization effects (at low and high Temperatures) have been investigated.  The experiments are conducted for different samples with high concentration of NWs as well as with lower concentration of NWs in the temperature range from 78 K (-195ºC) to 300 (27ºC). These photodiodes are designed to work in near infrared (NIR) spectral range.

     

    The results show that the NW photodetectors indeed are promising devices with fairly high break down voltage, change of photocurrent spectra with polarized light, low and constant reverse saturation current (Is). The impact of different polarized light on photocurrent spectra has been investigated and an attempt has been made to clarify the observed double peak of InP photocurrent spectrum. Our investigations also include a comparison to a conventional planar InP p-i-n photodetector.

     

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  • 26.
    Ak, Abdullah Cihan
    et al.
    Istanbul Technical University, Istanbul, Turkey.
    Aksoy, Eren
    Halmstad University, School of Information Technology.
    Sariel, Sanem
    Istanbul Technical University, Istanbul, Turkey.
    Learning Failure Prevention Skills for Safe Robot Manipulation2023In: IEEE Robotics and Automation Letters, E-ISSN 2377-3766, Vol. 8, no 12, p. 7994-8001Article in journal (Refereed)
    Abstract [en]

    Robots are more capable of achieving manipulation tasks for everyday activities than before. However, the safety of manipulation skills that robots employ is still an open problem. Considering all possible failures during skill learning increases the complexity of the process and restrains learning an optimal policy. Nonetheless, safety-focused modularity in the acquisition of skills has not been adequately addressed in previous works. For that purpose, we reformulate skills as base and failure prevention skills, where base skills aim at completing tasks and failure prevention skills aim at reducing the risk of failures to occur. Then, we propose a modular and hierarchical method for safe robot manipulation by augmenting base skills by learning failure prevention skills with reinforcement learning and forming a skill library to address different safety risks. Furthermore, a skill selection policy that considers estimated risks is used for the robot to select the best control policy for safe manipulation. Our experiments show that the proposed method achieves the given goal while ensuring safety by preventing failures. We also show that with the proposed method, skill learning is feasible and our safe manipulation tools can be transferred to the real environment © 2023 IEEE

  • 27.
    Akbari, Maryam
    et al.
    Iran University of Science and Technology, Tehran, Iran.
    Mirzakuchaki, Sattar
    Iran University of Science and Technology, Tehran, Iran.
    Fazeli, Mahdi
    Halmstad University, School of Information Technology.
    Tarihi, Mohammad Reza
    Niroo Research Institute, Tehran, Iran.
    Pure Magnetic Memory-Based PUFs: A Secure and Lightweight Solution for IoT Devices2023In: Iranian Journal of Electrical and Electronic Engineering, ISSN 2383-3890, Vol. 19, no 4, article id 2944Article in journal (Refereed)
    Abstract [en]

    In light of the growing prevalence of Internet of Things (IoT) devices, it has become essential to incorporate cryptographic protection techniques for high-security applications. Since IoT devices are resource-constraints in terms of power and area, finding cost-effective ways to enhance their security is necessary. Physical unclonable function (PUF) is considered a trusted hardware security mechanism that generates true and intrinsic randomness by extracting the inherent process variations of circuits. In this paper, a novel pure magnetic memory-based PUF is presented. The fundamental building blocks of the proposed PUF design are magnetic devices, the so-called mCells. These magnetoresistive devices exclusively utilize Magnetic Tunnel Junction (MTJ) components. Using purely MTJ in the main memory and sense amplifier in the proposed PUF leads to high randomness, high reliability, low power, and ultra-compact occupation area. The Monte Carlo HSPICE simulation results demonstrate that the proposed PUF achieves a uniqueness of 49.89%, uniformity of 50.02 %, power consumption of 1.43 µW, and an area occupation of 0.01 µm2 per bit. © 2023, Iran University of Science and Technology. All rights reserved.

  • 28.
    Akbari, Maryam
    et al.
    Iran University of Science and Technology, Tehran, Iran.
    Mirzakuchaki, Sattar
    Iran University of Science and Technology, Tehran, Iran.
    Jamshidi, Vahid
    Shahid Bahonar University of Kerman, Kerman, Iran.
    Fazeli, Mahdi
    Halmstad University, School of Information Technology.
    Tarihi, Mohammad Reza
    Niroo Research Institute (NRI), Tehran, Iran.
    An Ultra-compact Pure Magnetic Arbiter PUF with High Reliability and Low Power Consumption2023In: IEEE transactions on nanotechnology, ISSN 1536-125X, E-ISSN 1941-0085, Vol. 22, p. 449-456Article in journal (Refereed)
    Abstract [en]

    Due to the rugged environmental factors in IoT applications and constrained on-chip resources, PUF, as a critical hardware primitive, is a promising solution for key storage, authentication, and ID generation. The existing CMOS-based Arbiter PUFs mainly suffer from low reliability and vulnerability against modeling attacks. In this paper, the proposed PUF utilizes mCell devices, a class of Magnetoresistive devices employing only Magnetic Tunnel Junction (MTJ) devices, as a building block. Also, a novel nonvolatile latch is proposed to act as an arbiter and generates the responses by comparing the current values instead of delays which leads to increased the reliability by subtracting the constant variation rates of MTJs under environmental variation without adding hardware overhead. The characteristics of MTJ like nonvolatility, stochastic switching, chaotic magnetization, low power consumption, and low occupied area have made the proposed PUF to a low power, highly reliable, high randomness and ultra-compact pure magnetic arbiter PUF. The Monte Carlo HSPICE simulation results reveal that the uniformity, uniqueness, bit-aliasing, power consumption, and area of the proposed PUF are 49.24 %, 49.87 %, 48.64 %, 10.771 μW and 0.106 μm2, respectively. In addition, the average BER across a wide temperature range (-50C 150C) and voltage range (0.05 V-0.1 V) is 0.08 % and 0.18 %, respectively. © IEEE

  • 29.
    Akinola, Azeez Paul
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    chong, zhang
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Tunnel comparison between Generic Routing Encapsulation (GRE) and IP Security (IPSec)2012Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Since the introduction of networks, they have been used amongst home users, companies and organizations and most damage on the network is due to inappropriate security configurations. To secure networks, a protocol suite can be used to encrypt and authenticate all IP packets of a session. Therefore, this report will include the advantages and possible solution of some techniques used to offer increased network security such as scalability and data confidentiality. Captures of traffic sent using the two security techniques, IPSec/VPN and GRE-Tunnel will be monitored. The objective behind this project is to configure a network with these two different tunneling techniques and compare the security and network performance. The report also describes the security problems encountered by networks such as the ignorance of network users, vulnerabilities and the security of the devices.IPSecis a standard security protocol solution for TCP/IP, and it provides security through authentication, encryption and data integrity. GRE encapsulates packets and create a logical hub-and spoke topology of virtual point-to-point connections. The Jperf-tool is used to measure network performance and show specific details while another tool, Wireshark is used to analyze the information captured during transmission of data sent using IPSEC and GRE. The comparison further finds that IPSec-tunnel technique makes data transfers very secure but causes network performance disadvantages in comparison to a GRE solution.

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  • 30.
    Akinola, Azeez Paul
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Zhang, Chong
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Evaluate Security on the Internet Cafe2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Internet security (Network security) is a big topic that is very important in our society communication system, but it is extremely dynamic and wide in scope. This is the reason that many companies and organizations invest heavily in a dedicated infrastructure security and highly trained specialists.The aim of security monitoring and preventing the network from cyber threats requires vigilance over the network equipment. The case study of this thesis is to provide the possible solution to the problems encountered by the namely network users such as: Internet Game Center (Centrum Halmstad, Sweden) and, the Blueville Internet Cafe (Ede, Nigeria).Our research and information collected over the telephone and a visit at the nearest office. We concluded that both companies mentioned above experienced similar cyber threats. The two companies have internal and external threats such as accessing the network via ssh by using it brute force attack, network war-driver, the installation of spyware, password sniffer, viruses, SQL injection and PHP attacks (web attacks) on the networks. The cyber threats virus and spyware are among the big internet threat to users, organization and companies.We carry out experiments in the lab to tests for threats such as brute force (ssh) attack, password sniffer and war-driver in the Wireless environment. From the results, we are able to the select WPA2 using 802.1x as the best possible way to limit and reduce the strength of cyber-attacks, and as a suggested solution to the namely café problems in our report. We also list different suggestion and solution to the cyber café attacks from our research papers and information gathers from different sources such as library, internet, seminar and textbooks.

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  • 31.
    Aksoy, Eren
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Baci, Saimir
    Volvo Technology AB, Volvo Group Trucks Technology, Vehicle Automation, Gothenburg, Sweden.
    Cavdar, Selcuk
    Volvo Technology AB, Volvo Group Trucks Technology, Vehicle Automation, Gothenburg, Sweden.
    SalsaNet: Fast Road and Vehicle Segmentationin LiDAR Point Clouds for Autonomous Driving2020In: IEEE Intelligent Vehicles Symposium: IV2020, Piscataway, N.J.: IEEE, 2020, p. 926-932Conference paper (Refereed)
    Abstract [en]

    In this paper, we introduce a deep encoder-decoder network, named SalsaNet, for efficient semantic segmentation of 3D LiDAR point clouds. SalsaNet segments the road, i.e. drivable free-space, and vehicles in the scene by employing the Bird-Eye-View (BEV) image projection of the point cloud. To overcome the lack of annotated point cloud data, in particular for the road segments, we introduce an auto-labeling process which transfers automatically generated labels from the camera to LiDAR. We also explore the role of imagelike projection of LiDAR data in semantic segmentation by comparing BEV with spherical-front-view projection and show that SalsaNet is projection-agnostic. We perform quantitative and qualitative evaluations on the KITTI dataset, which demonstrate that the proposed SalsaNet outperforms other state-of-the-art semantic segmentation networks in terms of accuracy and computation time. Our code and data are publicly available at https://gitlab.com/aksoyeren/salsanet.git. 

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  • 32.
    Akyol, Gamze
    et al.
    Artificial Intelligence and Robotics Laboratory, Faculty of Computer and Informatics Engineering, Istanbul Technical University, Maslak, Turkey.
    Sariel, Sanem
    Artificial Intelligence and Robotics Laboratory, Faculty of Computer and Informatics Engineering, Istanbul Technical University, Maslak, Turkey.
    Aksoy, Eren Erdal
    Halmstad University, School of Information Technology.
    A Variational Graph Autoencoder for Manipulation Action Recognition and Prediction2021Conference paper (Refereed)
    Abstract [en]

    Despite decades of research, understanding human manipulation activities is, and has always been, one of the most attractive and challenging research topics in computer vision and robotics. Recognition and prediction of observed human manipulation actions have their roots in the applications related to, for instance, human-robot interaction and robot learning from demonstration. The current research trend heavily relies on advanced convolutional neural networks to process the structured Euclidean data, such as RGB camera images. These networks, however, come with immense computational complexity to be able to process high dimensional raw data.

    Different from the related works, we here introduce a deep graph autoencoder to jointly learn recognition and prediction of manipulation tasks from symbolic scene graphs, instead of relying on the structured Euclidean data. Our network has a variational autoencoder structure with two branches: one for identifying the input graph type and one for predicting the future graphs. The input of the proposed network is a set of semantic graphs which store the spatial relations between subjects and objects in the scene. The network output is a label set representing the detected and predicted class types. We benchmark our new model against different state-of-the-art methods on two different datasets, MANIAC and MSRC-9, and show that our proposed model can achieve better performance. We also release our source code https://github.com/gamzeakyol/GNet.

  • 33.
    Al Hayani, Musab
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Modeling Bus Load on CAN2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The existence of high load and latency in the CAN bus network would indeed lead to a situation where a given message crosses its deadline; this situation would disturb the continuity of the required service as well as activating fault codes due to delay of message delivery, which might lead to system failure.

    The outcome and goal of this thesis is to research and formulate methods to determine and model busload and latencies, by determining parameters such as alpha and breakdown utilization, which are considered as indications to the start of network breakdown when a given message in a dataset start to introduce latency by crossing its deadline which are totally prohibited in critical real time communications.

    The final goal of this master thesis is to develop a TOOL for calculating, modeling, determining and visualizing worst case busload, throughput, networks’ breakdown points and worst case latency in Scania CAN bus networks which is based on the J1939 protocol.

    SCANLA (The developed CAN busload analyzer tool in this thesis) is running as an executable application and uses a Graphical User Interface as a human-computer interface (i.e., a way for humans to interact with the tool) that useswindows,icons and menus and which can be manipulated by a mouse.

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  • 34.
    Alabdallah, Abdallah
    Halmstad University, School of Information Technology.
    Machine Learning Survival Models: Performance and Explainability2023Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Survival analysis is an essential statistics and machine learning field in various critical applications like medical research and predictive maintenance. In these domains understanding models' predictions is paramount. While machine learning techniques are increasingly applied to enhance the predictive performance of survival models, they simultaneously sacrifice transparency and explainability. 

    Survival models, in contrast to regular machine learning models, predict functions rather than point estimates like regression and classification models. This creates a challenge regarding explaining such models using the known off-the-shelf machine learning explanation techniques, like Shapley Values, Counterfactual examples, and others.   

    Censoring is also a major issue in survival analysis where the target time variable is not fully observed for all subjects. Moreover, in predictive maintenance settings, recorded events do not always map to actual failures, where some components could be replaced because it is considered faulty or about to fail in the future based on an expert's opinion. Censoring and noisy labels create problems in terms of modeling and evaluation that require to be addressed during the development and evaluation of the survival models.

    Considering the challenges in survival modeling and the differences from regular machine learning models, this thesis aims to bridge this gap by facilitating the use of machine learning explanation methods to produce plausible and actionable explanations for survival models. It also aims to enhance survival modeling and evaluation revealing a better insight into the differences among the compared survival models.

    In this thesis, we propose two methods for explaining survival models which rely on discovering survival patterns in the model's predictions that group the studied subjects into significantly different survival groups. Each pattern reflects a specific survival behavior common to all the subjects in their respective group. We utilize these patterns to explain the predictions of the studied model in two ways. In the first, we employ a classification proxy model that can capture the relationship between the descriptive features of subjects and the learned survival patterns. Explaining such a proxy model using Shapley Values provides insights into the feature attribution of belonging to a specific survival pattern. In the second method, we addressed the "what if?" question by generating plausible and actionable counterfactual examples that would change the predicted pattern of the studied subject. Such counterfactual examples provide insights into actionable changes required to enhance the survivability of subjects.

    We also propose a variational-inference-based generative model for estimating the time-to-event distribution. The model relies on a regression-based loss function with the ability to handle censored cases. It also relies on sampling for estimating the conditional probability of event times. Moreover, we propose a decomposition of the C-index into a weighted harmonic average of two quantities, the concordance among the observed events and the concordance between observed and censored cases. These two quantities, weighted by a factor representing the balance between the two, can reveal differences between survival models previously unseen using only the total Concordance index. This can give insight into the performances of different models and their relation to the characteristics of the studied data.

    Finally, as part of enhancing survival modeling, we propose an algorithm that can correct erroneous event labels in predictive maintenance time-to-event data. we adopt an expectation-maximization-like approach utilizing a genetic algorithm to find better labels that would maximize the survival model's performance. Over iteration, the algorithm builds confidence about events' assignments which improves the search in the following iterations until convergence.

    We performed experiments on real and synthetic data showing that our proposed methods enhance the performance in survival modeling and can reveal the underlying factors contributing to the explainability of survival models' behavior and performance.

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  • 35.
    Alam, Ashraful
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Parallelization of the Estimation Algorithm of the 3D Structure Tensor2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work provides the implementation of 3D structure tensor on a Massively Parallel Processor Array (MPPA), Ambric 2045.

     

    The 3D structure tensor algorithm is often used in image processing applications to compute the optical flow or to detect local 3D structures and their directions. The 3D structure tensor algorithm (3D-STA) consists of three main parts: gradient, tensor and smoothing. This algorithm is computationally expensive due to many multiplications and additions which are required to calculate the gradient (edge), the tensor and to smooth every pixel of the image. This is why this algorithm is very slow to run on a single processor. Therefore, it is important to make it parallel for high performance computation.

     

    This thesis provides two parallel implementations of 3D-STA; namely coarse-grained parallelism and fine-grained parallelism. Ambric has 336 processors. Only 49 processors are used in coarse-grained implementation and 165 processors are used in fine-grained implementation. The performance of the two implementations is measured using a video stream input, consisting of a sequence of images of size 20x256x256. The performance of the coarse-grained parallelism implementation is 25 frames per second (fps) and the one of the fine-grained parallelism implementation is 100 fps. Thus the fine-grained version is four time faster than the coarse-grained one.

     

    Additionally, the results are compared with the result of the Matlab implementation, running on Intel(R) Core 2 duo @2.10 GHz processor and also compared with another parallel optical flow implementation, in terms of speed and efficiency. The coarse-grained implementation is 58 times faster than the Matlab implementation and it achieves approximately half of the performance of the other parallel optical flow implementation. On the other hand, the fine-grained implementation is 230 times faster than the Matlab implementation and more than twice as (100/43) fast as the other parallel optical flow implementation.

     

    These performance results are satisfactory and the results that our parallel implementations can be considered for real-time applications.

     

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  • 36.
    Alam, Ashraful
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Ul-Abdin, Zain
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Svensson, Bertil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Parallelization of the Estimation Algorithm of the 3D Structure Tensor2012In: 2012 International Conference on Reconfigurable Computing and FPGAs, ReConFig 2012 / [ed] Peter Athanas, René Cumplido & Eduardo de la Torre, Piscataway, N.J.: IEEE Press, 2012, article id 6416771Conference paper (Refereed)
    Abstract [en]

    The three dimensional structure tensor algorithm (3D-STA) is often used in image processing applications to compute the optical flow or to detect local 3D structures and their directions. This algorithm is computationally expensive due to many computations that are required to calculate the gradient, the tensor, and to smooth every pixel of the image frames. Therefore, it is important to parallelize the implementation to achieve high performance. In this paper we present two parallel implementations of 3D-STA; namely moderately parallelized and highly parallelized implementation, on a massively parallel reconfigurable array. Finally, we evaluate the performance of the generated code and results are compared with another optical flow implementation. The throughput achieved by the moderately parallelized implementation is approximately half of the throughput of the Optical flow implementation, whereas the highly parallelized implementation results in a 2x gain in throughput as compared to the optical flow implementation. © 2012 IEEE.

  • 37.
    Alavijeh, Soroush Zamani
    et al.
    McMaster University, Hamilton, Canada.
    Zarrinkalam, Fattane
    University of Guelph, Guelph, Canada.
    Noorian, Zeinab
    Toronto Metropolitan University, Toronto, Canada.
    Mehrpour, Anahita
    University of Lausanne, Lausanne, Switzerland.
    Etminani, Kobra
    Halmstad University, School of Information Technology.
    What users’ musical preference on Twitter reveals about psychological disorders2023In: Information Processing & Management, ISSN 0306-4573, E-ISSN 1873-5371, Vol. 60, no 3, article id 103269Article in journal (Refereed)
    Abstract [en]

    Previous research found a strong relation between the users’ psychological disorders and their language use in social media posts in terms of vocabulary selection, emotional expressions, and psychometric attributes. However, although studying the association between psychological disorders and musical preference is considered as rather an old tradition in the clinical analysis of health data, it is not explored through the lens of social media analytics. In this study, we investigate which attributes of the music posted on social media are associated with mental health conditions of Twitter users. We created a large-scale dataset of 1519 Twitter users with six self-reported psychological disorders (depression, bipolar, anxiety, panic, post-traumatic stress disorder, and borderline) and matched with 2480 control users. We then conduct an observational study to investigate the relationship between the users’ psychological disorders and their musical preference by analyzing lyrics of the music tracks that the users shared on Twitter from multiple dimensions including word usage, linguistic style, sentiment and emotion patterns, topical interests and underlying semantics. Our findings reveal descriptive differences on the linguistic and semantic features of music tracks of affected users compared to control individuals and among users from different psychological disorders. Additionally, we build a feature-based and an (explainable) deep learning-based binary classifiers trained on disorder and control users and demonstrate that lyrics of the music tracks of users on Twitter can be considered as complementary information to their published posts to improve the accuracy of the disorder detection task. Overall, we find that the music attributes of users on Twitter allow inferences about their mental health status. © 2023 Elsevier Ltd

  • 38.
    Albayrak, Aras
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Automatic Pose and Position Estimation by Using Spiral Codes2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis is about providing the implementation of synthesis, detection of spiral symbols and estimating the pan/tilt angle and position by using camera calibration. The focus is however on the latter, the estimation of parameters of localization.

    Spiral symbols are used to be able to give an object an identity as well as to locate it. Due to the spiral symbol´s characteristic shape, we can use the generalized structure tensor (GST) algorithm which is particularly efficient to detect different members of the spiral family. Once we detect spirals, we know the position and identity parameters of the spirals within an apriori known geometric configuration (on a sheet of paper). In turn, this information can be used to estimate the 3D-position and orientation of the object on which spirals are attached using a camera calibration method.

     

    This thesis provides an insight into how automatic detection of spirals attached on a sheet of paper, and from this, automatic deduction of position and pose parameters of the sheet, can be achieved by using a network camera. GST algorithm has an advantage of running the processes of detection of spirals efficiently w.r.t detection performance and computational resources because it uses a spiral image model well adapted to spiral spatial frequency characteristic. We report results on how detection is affected by zoom parameters of the network camera, as well as by the GST parameters; such as filter size. After all spirals centers are located and identified w.r.t. their twist/bending parameter, a flexible technique for camera calibration, proposed by Zhengyou Zhang implemented in Matlab within the present study, is performed. The performance of the position and pose estimation in 3D is reported.

    The main conclusion is, we have reasonable surface angle estimations for images which were taken by a WLAN network camera in different conditions such as different illumination and different distances. 

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  • 39.
    Albinsson, John
    et al.
    Lund Univ, Dept Biomed Engn, S-22100 Lund, Sweden..
    Brorsson, Sofia
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Rydén Ahlgren, Åsa
    Lund Univ, Dept Clin Sci, Clin Physiol & Nucl Med Unit, Malmo, Sweden..
    Cinthio, Magnus
    Lund Univ, Dept Biomed Engn, S-22100 Lund, Sweden..
    Improved tracking performance of lagrangian block-matching methodologies using block expansion in the time domain: In silico, phantom and invivo evaluations2014In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 40, no 10, p. 2508-2520Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate tracking performance when an extra reference block is added to a basic block-matching method, where the two reference blocks originate from two consecutive ultrasound frames. The use of an extra reference block was evaluated for two putative benefits: (i) an increase in tracking performance while maintaining the size of the reference blocks, evaluated using in silico and phantom cine loops; (ii) a reduction in the size of the reference blocks while maintaining the tracking performance, evaluated using in vivo cine loops of the common carotid artery where the longitudinal movement of the wall was estimated. The results indicated that tracking accuracy improved (mean - 48%, p<0.005 [in silico]; mean - 43%, p<0.01 [phantom]), and there was a reduction in size of the reference blocks while maintaining tracking performance (mean - 19%, p<0.01 [in vivo]). This novel method will facilitate further exploration of the longitudinal movement of the arterial wall. (C) 2014 World Federation for Ultrasound in Medicine & Biology.

  • 40.
    Alendal, Gunnar
    et al.
    NTNU, Gjøvik, Norway.
    Dyrkolbotn, Geir Olav
    NTNU, Gjøvik, Norway & Norwegian Defence Cyber Academy (NDCA), Jørstadmoen, Norway.
    Axelsson, Stefan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Forensics acquisition – Analysis and circumvention of samsung secure boot enforced common criteria mode2018In: Digital Investigation. The International Journal of Digital Forensics and Incident Response, ISSN 1742-2876, E-ISSN 1873-202X, Vol. 24, no Suppl., p. S60-S67Article in journal (Refereed)
    Abstract [en]

    The acquisition of data from mobile phones have been a mainstay of criminal digital forensics for a number of years now. However, this forensic acquisition is getting more and more difficult with the increasing security level and complexity of mobile phones (and other embedded devices). In addition, it is often difficult or impossible to get access to design specifications, documentation and source code. As a result, the forensic acquisition methods are also increasing in complexity, requiring an ever deeper understanding of the underlying technology and its security mechanisms. Forensic acquisition techniques are turning to more offensive solutions to bypass security mechanisms, through security vulnerabilities. Common Criteria mode is a security feature that increases the security level of Samsung devices, and thus make forensic acquisition more difficult for law enforcement. With no access to design documents or source code, we have reverse engineered how the Common Criteria mode is actually implemented and protected by Samsung's secure bootloader. We present how this security mode is enforced, security vulnerabilities therein, and how the discovered security vulnerabilities can be used to circumvent Common Criteria mode for further forensic acquisition. © 2018 The Author(s). Published by Elsevier Ltd on behalf of DFRWS.

  • 41.
    Alfakir, Omar
    et al.
    Halmstad University, School of Information Technology.
    Larsson, Viktor
    Halmstad University, School of Information Technology.
    Alonso-Fernandez, Fernando
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    A Cross-Platform Mobile Application for Ambulance CPR during Cardiac Arrests2021In: 2021 8th International Conference on Soft Computing & Machine Intelligence (ISCMI), Piscataway: IEEE, 2021, p. 120-124Conference paper (Refereed)
    Abstract [en]

    This paper describes the implementation of a cross-platform software application to aid ambulance paramedics during CPR (Cardio-Pulmonary Resuscitation). It must be able to work both on iOS and Android devices, which are the leading platforms in the mobile industry. The goal of the application is to guide paramedics in the different processes and expected medication to be administered during a cardiac arrest, a scenario that is usually stressful and fast-paced, thus prone to errors or distractions. The tool must provide timely reminders of the different actions to be performed during a cardiac arrest, and in an appropriate order, based on the results of the previous actions. A timer function will also control the duration of each step of the CPR procedure. The application is implemented in React Native which, using JavaScript as programming language, allows to deploy applications that can run both in iOS and Android native languages. Our solution could also serve as a record of events that could be transmitted (even in real-time) to the hospital without demanding explicit verbal communication of the procedures or medications administered to the patient during the ambulance trip. This would provide even higher efficiency in the process, and would allow automatic incorporation of the events to the medical record of the patient as well. © 2021 IEEE.

  • 42.
    Alfredsson, Anders
    Halmstad University, School of Information Technology.
    Cybersäkerhet på väg: Säker mjukvaruutveckling i fordonsindustrin2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Moderna vägfordon är i högre grad än tidigare styrda av mjukvara, och det är även vanligt att de har någon form av internetuppkoppling. För att fordonen ska kunna uppfylla de säkerhetskrav som ställs är det därför viktigt att mjukvaran är utvecklad på ett säkert sätt och under säkra former. Denna fallstudie undersöker med hjälp av strukturerade intervjuer hur några personer som arbetar med mjukvaruutveckling inom fordonsindustrin beskriver arbetet med säkerhet i utvecklingsprocessen. Resultatet visar att det finns en rad olika rutiner och riktlinjer som syftar till att skapa en säker produkt ur ett cybersäkerhetsperspektiv, men att det finns en tendens bland vissa utvecklare att förlita sig på processer och rutiner när det gäller att skapa en säker mjukvara.

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  • 43.
    Alhamarna, Ahmed
    et al.
    Halmstad University, School of Information Technology.
    Kjellgren, Simon
    Halmstad University, School of Information Technology.
    IDENTIFIERING AV ELEKTRONIKSKROT2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is the result of a survey carried out by two students at Halmstad University. The study was conducted at the request of the recycling company, with the purpose to explore opportunities for streamlining the screening pro- cess of electronic waste products. The question that was asked was if RFID could be used for identification of the scrap. The project members started their work to investigate if RFID was the best identification method where the advantages and disadvantages of various automated systems were com- pared. The conclusion drawn was that RFID could be a viable solution in the future, provided that manufacturers of electronics integrate RFID tags into their products. Given that increasingly more producers are using RFID to locate and identify their products during production and the falling price of passive tags, it is possible that labeling products with RFID tags could become a standard, both for more efficient logistics and a more efficient re- cycling process. 

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  • 44.
    Alharthi, Mohannad
    et al.
    School of Computing, Queen's University, Kingston, Ontario, Canada.
    Taha, Abd-Elhamid M.
    Electrical Engineering Department, Alfaisal University, Riyadh, Saudi Arabia.
    Vasilev, Viktor
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Atkinson, Kevin
    Department of Computer Science, Rice University, Houston, USA.
    An Acumen/NS-3 integration for modeling networked Cyber-Physical Systems2014Conference paper (Refereed)
    Abstract [en]

    Capturing physical phenomena such as node mobility or wave propagation is challenging in current network simulators, and is mostly achieved through crude abstractions. Despite being operationally efficient, such abstractions adversely affect simulation credibility. To realize more accurate modeling, we are currently developing a simulation environment integrating a hybrid modeling language into a mainstream network simulator. This paper gives a preliminary overview of our efforts. For illustration, an example simulation scenario with some basic mobility is described. © 2014 IEEE.

  • 45.
    Ali Hamad, Rebeen
    Halmstad University, School of Information Technology.
    Towards Reliable, Stable and Fast Learning for Smart Home Activity Recognition2022Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The current population age grows increasingly in industrialized societies and calls for more intelligent tools to monitor human activities.  The aims of these intelligent tools are often to support senior people in their homes, to keep track of their daily activities, and to early detect potential health problems to facilitate a long and independent life.  The recent advancements of smart environments using miniaturized sensors and wireless communications have facilitated unobtrusively human activity recognition.  

    Human activity recognition has been an active field of research due to its broad applications in different areas such as healthcare and smart home monitoring. This thesis project develops work on machine learning systems to improve the understanding of human activity patterns in smart home environments. One of the contributions of this research is to process and share information across multiple smart homes to reduce the learning time, reduce the need and effort to recollect the training data, as well as increase the accuracy for applications such as activity recognition. To achieve that, several contributions are presented to pave the way to transfer knowledge among smart homes that includes the following studies. Firstly, a method to align manifolds is proposed to facilitate transfer learning. Secondly, we propose a method to further improve the performance of activity recognition over the existing methods. Moreover, we explore imbalanced class problems in human activity recognition and propose a method to handle imbalanced human activities. The summary of these studies are provided below. 

    In our work, it is hypothesized that aligning learned low-dimensional  manifolds from disparate datasets could be used to transfer knowledge between different but related datasets. The t-distributed Stochastic Neighbor Embedding(t-SNE) is used to project the high-dimensional input dataset into low-dimensional manifolds. However, since t-SNE is a stochastic algorithm and  there is a large variance of t-SNE maps, a thorough analysis of the stability is required before applying  Transfer learning.  In response to this, an extension to Local Procrustes Analysis called Normalized Local Procrustes Analysis (NLPA) is proposed to non-linearly align manifolds by using locally linear mappings to test the stability of t-SNE low-dimensional manifolds. Experiments show that the disparity from using NLPA to align low-dimensional manifolds decreases by order of magnitude compared to the disparity obtained by Procrustes Analysis (PA). NLPA outperforms PA and provides much better alignments for the low-dimensional manifolds. This indicates that t-SNE low-dimensional manifolds are locally stable, which is the part of the contribution in this thesis.

    Human activity recognition in smart homes shows satisfying recognition results using existing methods. Often these methods process sensor readings that precede the evaluation time (where the decision is made) to evaluate and deliver real-time human activity recognition. However, there are several critical situations, such as diagnosing people with dementia where "preceding sensor activations" are not always sufficient to accurately recognize the resident's daily activities in each evaluated time. To improve performance, we propose a method that delays the recognition process to include some sensor activations that occur after the point in time where the decision needs to be made. For this, the proposed method uses multiple incremental fuzzy temporal windows to extract features from both preceding and some oncoming sensor activations. The proposed method is evaluated with two temporal deep learning models: one-dimensional convolutional neural network (1D CNN) and long short-term memory (LSTM) on a binary sensor dataset of real daily living activities.  The experimental evaluation shows that the proposed method achieves significantly better results than the previous state-of-the-art. 

    Further, one of the main problems of activity recognition in a smart home setting is that the frequency and duration of human activities are intrinsically imbalanced. The huge difference in the number of observations for the categories means that many machine learning algorithms focus on the classification of the majority examples due to their increased prior probability while ignoring or misclassifying minority examples. This thesis explores well-known class imbalance approaches (synthetic minority over-sampling technique, cost-sensitive learning and ensemble learning) applied to activity recognition data with two temporal data pre-processing for the deep learning models LSTM and 1D CNN. This thesis proposes a data level perspective combined with a temporal window technique to handle imbalanced human activities from smart homes in order to make the learning algorithms more sensitive to the minority class. The experimental results indicate that handling imbalanced human activities from the data-level outperforms algorithm level and improved the classification performance.

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  • 46.
    Ali Hamad, Rebeen
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Salguero Hidalgo, Alberto
    University of Cádiz, Cádiz, Spain.
    Bouguelia, Mohamed-Rafik
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Estevez, Macarena Espinilla
    University of Jaén, Jaén, Spain.
    Quero, Javier Medina
    University of Jaén, Jaén, Spain.
    Efficient Activity Recognition in Smart Homes Using Delayed Fuzzy Temporal Windows on Binary Sensors2020In: IEEE journal of biomedical and health informatics, ISSN 2168-2194, E-ISSN 2168-2208, Vol. 24, no 2, p. 387-395Article in journal (Refereed)
    Abstract [en]

    Human activity recognition has become an active research field over the past few years due to its wide application in various fields such as health-care, smart home monitoring, and surveillance. Existing approaches for activity recognition in smart homes have achieved promising results. Most of these approaches evaluate real-time recognition of activities using only sensor activations that precede the evaluation time (where the decision is made). However, in several critical situations, such as diagnosing people with dementia, “preceding sensor activations” are not always sufficient to accurately recognize the inhabitant's daily activities in each evaluated time. To improve performance, we propose a method that delays the recognition process in order to include some sensor activations that occur after the point in time where the decision needs to be made. For this, the proposed method uses multiple incremental fuzzy temporal windows to extract features from both preceding and some oncoming sensor activations. The proposed method is evaluated with two temporal deep learning models (convolutional neural network and long short-term memory), on a binary sensor dataset of real daily living activities. The experimental evaluation shows that the proposed method achieves significantly better results than the real-time approach, and that the representation with fuzzy temporal windows enhances performance within deep learning models. © Copyright 2020 IEEE

  • 47.
    Ali, Mustafa
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Abid, Hussain
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Wireless and Industrial Network2013Independent thesis Basic level (degree of Bachelor), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to implement the wireless network in a company withtwo different sites which is located in Riga and Malmo. The main task of this reportis to implement and configure wireless industrial network. This report is based oninformation we gathered from the ABC Company about their requirements for awireless network.Requirements of this ABC Company is focusing on their infrastructure planning,security and implementing them. Benefits and drawbacks of industrial wirelessnetwork will be described briefly in this report to get some idea how ABC Companywill face the problem when they will implement their wireless network.

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    Student thesis
  • 48.
    Al-imarah, Amena
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Stenberg, Elin
    Halmstad University, School of Business, Engineering and Science.
    Tillämpning av batterilager som energitjänsten lastutjämnare: En studie om batterilagring för en medelstor abonnent i Varberg Energis elnät2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis, is a study of battery energy storage and its use as energy source and smoothening of power fluctuation. Studies have been made as a systematic review and a quantitative study. The study has consisted of analysing the power characteristic from a supermarket in the city of Varberg during year 2015. The object has been to evaluate the energy storage and the power smoothing qualities. Therefore the battery energy storages characteristics have been evaluated in this systematic review. For the quantitative study, calculations of the energy storage sizes were made for two separate operation modes. The two different operation modes were named technical dimensioning and economic dimensioning. The function of the technical dimensioning was to smooth the power outlet from the grid, while the function of the economic dimensioning was to enable the supermarket to buy more energy during low-price hours. Based on monthly power characteristics, each dimensioning gave as a result two energy storage possibilities, one in medium and one in small size. The technical dimensioning resulted in battery energy storage of the sizes 617 kWh and 555kWh which is comparable to 7,1% and 5,8% of the daily energy usage of the supermarket. The economic dimensioning resulted in battery energy storage of the sizes 597 kWh and 233kWh which is comparable to 6,8% and 2,8% of the daily energy usage of the supermarket. For optimizing the economic savings, a variation of technical and economic operation mode are needed, depending on calculated power usage through the day and elspot prices. The study shows that a battery storage is difficult to finance. The calculated economic savings were estimated during ideal conditions and without power loss or loss in performance. As a conclusion from this study a battery storage may have a good payback if there are several energy services to be filled.

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  • 49.
    Aljoundi, Ahmad
    et al.
    Halmstad University, School of Information Technology.
    Abukarsh, Wael
    Halmstad University, School of Information Technology.
    Testrigg för att hantera NFC-taggar och QR-koder2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Automation of test processes is essential because manual tests are complicated and time-consuming. Automating the test processes makes the test work more efficient and increases quality. The work described in this diploma thesis was performed at Phoniro AB in Halmstad, and the purpose of the project is to identify and construct a fully automated solution for the scanning of NFC tags and QR codes. The report describes a design that meets the requirements and needs established for the development models used in the project. A mechanical test rig was constructed as a suitable solution, based on developed requirements during the project. Evaluation matrices were used to select the most suitable software and hardware platforms for the test rig based on the project needs. The test rig consists of a 3D-model, a circuit board, and a software component to program the test rig and integrate it with Phoniro’s test framework. The test rig developed is a prototype with excellent potential for future development.

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  • 50.
    Alkabani, Yousra
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Electrical & Computer Engineering Department, George Washington University, Washington, DC, USA.
    Miscuglio, Mario
    Electrical & Computer Engineering Department, George Washington University, Washington, DC, USA.
    Sorger, Volker J.
    Electrical & Computer Engineering Department, George Washington University, Washington, DC, USA.
    El-Ghazawi, Tarek
    Electrical & Computer Engineering Department, George Washington University, Washington, DC, USA.
    OE-CAM: A Hybrid Opto-Electronic Content Addressable Memory2020In: IEEE Photonics Journal, E-ISSN 1943-0655, Vol. 12, no 2, article id 6600114Article in journal (Refereed)
    Abstract [en]

    A content addressable memory (CAM) is a type of memory that implements a parallel search engine at its core. A CAM takes as an input a value and outputs the address where this value is stored in case of a match. CAMs are used in a wide range of applications including networking, cashing, neuromorphic associative memories, multimedia, and data analytics. Here, we introduce a novel opto-electronic CAM (OE-CAM) utilizing the integrated silicon photonic platform. In our approach, we explore the performance of an experimental OE-CAM and verify the efficiency of the device at 25 Gbit/s while maintaining the bit integrity under noise conditions. We show that OE-CAM enables a) two orders of magnitude faster search functionality resulting in b) a five orders of magnitude lower power-delay-product compared to CAMs implementations based on other emerging technologies. This remarkable performance potential is achieved by utilizing i) a high parallelism of wavelength-division-multiplexing in the optical domain, combined with ii) 10's of GHz-fast opto-electronic components, packaged in iii) integrated photonics for 10-100's ps-short communication delays. We further verify the upper optical input power limit of this OE-CAM to be given by parasitic nonlinearities inside the silicon waveguides, and the minimal detectable optical power at the back-end photoreceiver's responsivity given channel noise. Such energy-efficient and short-delay OE-CAMs could become a key component of functional photonic-augmented ASICS, co-processors, or smart sensors. © IEEE

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