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  • 2801.
    Jiang, Yuning
    et al.
    University of Skövde, School of Informatics. University of Skövde, Informatics Research Environment.
    Atif, Yacine
    University of Skövde, School of Informatics. University of Skövde, Informatics Research Environment.
    An Approach to Discover and Assess Vulnerability Severity Automatically in Cyber-Physical Systems2020In: Proceedings of the 13th International Conference on Security of Information and Networks: November 4-6, 2020, virtual, Istanbul, Turkey / [ed] Berna Örs, Atilla Elçi, New York, NY, USA: Association for Computing Machinery (ACM), 2020, article id 9Conference paper (Refereed)
    Abstract [en]

    Current vulnerability scoring mechanisms in complex cyber-physical systems (CPSs) face challenges induced by the proliferation of both component versions and recurring scoring-mechanism versions. Different data-repository sources like National Vulnerability Database (NVD), vendor websites as well as third party security tool analysers (e.g. ICS CERT and VulDB) may provide conflicting severity scores. We propose a machine-learning pipeline mechanism to compute vulnerability severity scores automatically. This method also discovers score correlations from established sources to infer and enhance the severity consistency of reported vulnerabilities. To evaluate our approach, we show through a CPS-based case study how our proposed scoring system automatically synthesises accurate scores for some vulnerability instances, to support remediation decision-making processes. In this case study, we also analyse the characteristics of CPS vulnerability instances. 

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  • 2802.
    Jiang, Yuning
    et al.
    University of Skövde, Informatics Research Environment. University of Skövde, School of Informatics.
    Jeusfeld, Manfred A.
    University of Skövde, School of Informatics. University of Skövde, Informatics Research Environment.
    Ding, Jianguo
    University of Skövde, School of Informatics. University of Skövde, Informatics Research Environment.
    Evaluating the Data Inconsistency of Open-Source Vulnerability Repositories2021In: ARES 2021: The 16th International Conference on Availability, Reliability and Security, Association for Computing Machinery (ACM), 2021, p. 1-10, article id 86Conference paper (Refereed)
    Abstract [en]

    Modern security practices promote quantitative methods to provide prioritisation insights and support predictive analysis, which is supported by open-source cybersecurity databases such as the Common Vulnerabilities and Exposures (CVE), the National Vulnerability Database (NVD), CERT, and vendor websites. These public repositories provide a way to standardise and share up-to-date vulnerability information, with the purpose to enhance cybersecurity awareness. However, data quality issues of these vulnerability repositories may lead to incorrect prioritisation and misemployment of resources. In this paper, we aim to empirically analyse the data quality impact of vulnerability repositories for actual information technology (IT) and operating technology (OT) systems, especially on data inconsistency. Our case study shows that data inconsistency may misdirect investment of cybersecurity resources. Instead, correlated vulnerability repositories and trustworthiness data verification bring substantial benefits for vulnerability management. 

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  • 2803.
    Jiang, Yuning
    et al.
    Högskolan i Skövde, Forskningsmiljön Informationsteknologi.
    Jeusfeld, Manfred A.
    Högskolan i Skövde, Institutionen för informationsteknologi.
    Ding, Jianguo
    Högskolan i Skövde, Institutionen för informationsteknologi.
    Evaluating the Data Inconsistency of Open-Source Vulnerability Repositories2021In: ARES 2021: The 16th International Conference on Availability, Reliability and Security, Association for Computing Machinery (ACM) , 2021, p. 1-10, article id 86Conference paper (Refereed)
    Abstract [en]

    Modern security practices promote quantitative methods to provide prioritisation insights and support predictive analysis, which is supported by open-source cybersecurity databases such as the Common Vulnerabilities and Exposures (CVE), the National Vulnerability Database (NVD), CERT, and vendor websites. These public repositories provide a way to standardise and share up-to-date vulnerability information, with the purpose to enhance cybersecurity awareness. However, data quality issues of these vulnerability repositories may lead to incorrect prioritisation and misemployment of resources. In this paper, we aim to empirically analyse the data quality impact of vulnerability repositories for actual information technology (IT) and operating technology (OT) systems, especially on data inconsistency. Our case study shows that data inconsistency may misdirect investment of cybersecurity resources. Instead, correlated vulnerability repositories and trustworthiness data verification bring substantial benefits for vulnerability management. 

  • 2804.
    Jiang, Zuoying
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Predicting Service Metrics from Device Statistics in a Container-Based Environment2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Service assurance is critical for high-demand services running on telecom clouds. While service performance metrics may not always be available in real time to telecom operators or service providers, service performance prediction becomes an important building block for such a system. However, it is generally hard to achieve. 

    In this master thesis, we propose a machine-learning based method that enables performance prediction for services running in virtualized environments with Docker containers. This method is service agnostic and the prediction models built by this method use only device statistics collected from the server machine and from the containers hosted on it to predict the values of the service-level metrics experienced on the client side. 

    The evaluation results from the testbed, which runs a Video-on-Demand service using containerized servers, show that such a method can accurately predict different service-level metrics under various scenarios and, by applying suitable preprocessing techniques, the performance of the prediction models can be further improved. 

    In this thesis, we also show the design of a proof-of-concept of a Real-Time Analytics Engine that uses online learning methods to predict the service-level metrics in real time in a container-based environment.

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  • 2805. Jidrot, Rune
    et al.
    Perumal, Gnanapalaniselvi
    Workload Characterization and Performance Evaluation of a Blockchain Implementation for Managing Federated Cloud Resources - Assuming a Peer-to-peer Energy Management Use Case2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Blockchain technology has become an appealing concept in Distributed Systems because it enables a distributed storage of information, replacing a central database [1]. In addition, Blockchains promise to address inherent and difficult issues in distributed systems such as a) proving the provenance of information, i.e., the documentation where pieces of data comes from (including their the processing), and b) that the information has not been changed, i.e., the integrity of the information has not been corrupted. The data in a Blockchain is said to be immutable.

    In this thesis, we apply Blockchain technology as a concept in Distributed Systems for securely collecting and storing data from distributed cloud resources that must be intact over a longer amount of time, such as the amount of consumed cloud resources characterized by CPU load or energy usage. In particular, this work considers a peer-to-peer energy use case where virtual energy resources are monitored.

    The focus of this thesis is on a) how a Blockchain for a distributed Cloud monitoring can be implemented, b) how the workload can be characterized and c) how the Blockchain system’s performance can be observed and what performance can be achieved. Therefore, the work defines an initial system model, provide an implementation, and carries out experiments in order to understand the impact of the design factors and the system input to the capabilities and performance of the system. The results of the experiments, the workload characterization and performance analysis, are analysed by statistical means and provided as graphs.

    The choices of system models, Blockchain technology (Hyperledger Fabric), and other parameters, are based on the literature review. The experimental implementation is, in turn, based on the selected system model, where we want to experimentally identify limitations and bottlenecks of the performance.

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  • 2806.
    Jimenez, Lara Lorna
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Decentralized Location-aware Orchestration of Containerized Microservice Applications: Enabling Distributed Intelligence at the Edge2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Services that operate on public, private, or hybrid clouds, should always be available and reachable to their end-users or clients. However, a shift in the demand for current and future services has led to new requirements on network infrastructure, service orchestration, and Quality-of-Service (QoS). Services related to, for example, online-gaming, video-streaming, smart cities, smart homes, connected cars, or other Internet-of-Things (IoT) powered use cases are data-intensive and often have real-time and locality requirements. These have pushed for a new computing paradigm, Edge computing, based on moving some intelligence from the cloud to the edge of the network to minimize latency and data transfer. This situation has set new challenges for cloud providers, telecommunications operators, and content providers. This thesis addresses two issues in this problem area that call for distinct approaches and solutions. Both issues share the common objectives of improving energy-efficiency and mitigating network congestion by minimizing data transfer to boost service performance, particularly concerning latency, a prevalent QoS metric. The first issue is related to the demand for a highly scalable orchestrator that can manage a geographically distributed infrastructure to deploy services efficiently at clouds, edges, or a combination of these. We present an orchestrator using process containers as the virtualization technology for efficient infrastructure deployment in the cloud and at the edge. The work focuses on a Proof-of-Concept design and analysis of a scalable and resilient decentralized orchestrator for containerized applications, and a scalable monitoring solution for containerized processes. The proposed orchestrator deals with the complexity of managing a geographically dispersed and heterogeneous infrastructure to efficiently deploy and manage applications that operate across different geographical locations — thus facilitating the pursuit of bringing some of the intelligence from the cloud to the edge, in a way that is transparent to the applications. The results show this orchestrator’s ability to scale to 20 000 nodes and to deploy 30 000 applications in parallel. The resource search algorithm employed and the impact of location awareness on the orchestrator’s deployment capabilities were also analyzed and deemed favorable. The second issue is related to enabling fast real-time predictions and minimizing data transfer for data-intensive scenarios by deploying machine learning models at devices to decrease the need for the processing of data by upper tiers and to decrease prediction latency. Many IoT or edge devices are typically resource-scarce, such as FPGAs, ASICs, or low-level microcontrollers. Limited devices make running well-known machine learning algorithms that are either too complex or too resource-consuming unfeasible. Consequently, we explore developing innovative supervised machine learning algorithms to efficiently run in settings demanding low power and resource consumption, and realtime responses. The classifiers proposed are computationally inexpensive, suitable for parallel processing, and have a small memory footprint. Therefore, they are a viable choice for pervasive systems with one or a combination of these limitations, as they facilitate increasing battery life and achieving reduced predictive latency. An implementation of one of the developed classifiers deployed to an off-the-shelf FPGA resulted in a predictive throughput of 57.1 million classifications per second, or one classification every 17.485 ns.

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  • 2807.
    Jimenez, Raúl
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Knutsson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    CTracker: a Distributed BitTorrent Tracker Based on Chimera2008In: Collaboration and the Knowledge Economy: Issues, Applications, Case Studies / [ed] Paul Cunningham and Miriam Cunningham, Amsterdam: IOS Press , 2008, p. 941-947Conference paper (Refereed)
    Abstract [en]

    There are three major open issues in the BitTorrent peer discovery system, which are not solved by any of the currently deployed solutions. These issues seriously threaten BitTorrent's scalability, especially when considering that mainstream content distributors could start using BitTorrent for distributing content to millions of users simultaneously in the near future.

    In this paper these issues are addressed by proposing a topology-aware distributed tracking system as a replacement for both centralized and Kademlia-based trackers.

    An experiment measuring most popular open BitTorrent trackers is also presented. It shows that centralized trackers are not topology aware. We conclude that an ideal topology-aware tracker would return peers whose latency to the requester peer is significantly lower than of a centralized tracker.

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  • 2808.
    Jin, Junchen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Adaptive Group-Based Signal Control Using Reinforcement Learning with Eligibility Traces2015In: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, IEEE conference proceedings, 2015, p. 2412-2417Conference paper (Refereed)
    Abstract [en]

    Group-based signal controllers are widely deployed on urban networks in the Nordic countries. However, group-based signal controls are usually implemented with rather simple timing logics, e.g. vehicle actuated timing. In addition, group-based signal control systems with pre-defined signal parameter settings show relatively poor performances in a dynamically changed traffic environment. This study, therefore, presents an adaptive group-based signal control system capable of changing control strategies with respect to non-stationary traffic demands. In this study, signal groups are formulated as individual agents. The signal group agent learns from traffic environments and makes intelligent timing decisions according to the perceived system states. Reinforcement learning with multiple-step backups is applied as the learning algorithm. Agents on-line update their knowledge based on a sequence of states during the learning process rather than purely on the basis of single previous state. The proposed signal control system is integrated into a software-in-the-loop simulation (SILS) framework for evaluation purpose. In the testbed experiments, the proposed adaptive group-based control system is compared to a benchmark signal control system, the well-established group-based fixed-time control system. The simulation results demonstrate that learning-based and adaptive group-based signal control system owns its advantage in dealing with dynamic traffic environments in terms of improving traffic mobility efficiency.

  • 2809.
    Jin, Junchen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Implementation and Optimization of Group-based Signal Control in Traffic Simulation2014In: 2014 IEEE 17TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC), 2014, p. 2517-2522Conference paper (Refereed)
    Abstract [en]

    Over the past decades, group-based control has become one of the most popular signal technologies being applied in many cities around the world. LHOVRA control is one of such group-based controls widely employed in Scandinavian countries. While several previous studies showed that group-based control outperforms stage-based control in many aspects, implementation and evaluation of signal controllers are complicated in a real application. In addition, little effort has been put in optimizing such group-based controllers in traffic management practice. This study implements generic group-based control in an object-oriented software framework, while a software-in-the-loop simulation is developed to integrate the signal controller with an open-source traffic simulator, SUMO. Also, stochastic optimization is applied to generate optimal signal parameters according to different settings of objective. In particular, part of the study is to improve the computational performance of the optimization process by parallelized simulation runs. Test-based experiments are finally carried out to evaluate traffic and optimize its impact on a small traffic network in Stockholm.

  • 2810.
    Jin, Yi
    et al.
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Cai, Jiawei
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Xu, Jiawei
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Huan, Yuxiang
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems. Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China.
    Yan, Yulong
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Huang, Bin
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Guo, Yongliang
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Zheng, Lirong
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Zou, Zhuo
    Fudan Univ, Sch Informat Sci & Technol, State Key Lab ASIC & Syst, Shanghai, Peoples R China..
    Self-aware distributed deep learning framework for heterogeneous IoT edge devices2021In: Future generations computer systems, ISSN 0167-739X, E-ISSN 1872-7115, Vol. 125, p. 908-920Article in journal (Refereed)
    Abstract [en]

    Implementing artificial intelligence (AI) in the Internet of Things (IoT) involves a move from the cloud to the heterogeneous and low-power edge, following an urgent demand for deploying complex training tasks in a distributed and reliable manner. This work proposes a self-aware distributed deep learning (DDL) framework for IoT applications, which is applicable to heterogeneous edge devices aiming to improve adaptivity and amortize the training cost. The self-aware design including the dynamic self-organizing approach and the self-healing method enhances the system reliability and resilience. Three typical edge devices are adopted with cross-platform Docker deployment: Personal Computers (PC) for general computing devices, Raspberry Pi 4Bs (Rpi) for resource-constrained edge devices, and Jetson Nanos (Jts) for AI-enabled edge devices. Benchmarked with ResNet-32 on CIFAR-10, the training efficiency of tested distributed clusters is increased by 8.44x compared to the standalone Rpi. The cluster with 11 heterogeneous edge devices achieves a training efficiency of 200.4 images/s and an accuracy of 92.45%. Results prove that the self-organizing approach functions well with dynamic changes like devices being removed or added. The self-healing method is evaluated with various stabilities, cluster scales, and breakdown cases, testifying that the reliability can be largely enhanced for extensively distributed deployments. The proposed DDL framework shows excellent performance for training implementation with heterogeneous edge devices in IoT applications with high-degree scalability and reliability.

  • 2811.
    Jingili, Nuru
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Oyelere, Solomon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Ojwang, Frank
    Faculty of Social Sciences, University of Lapland, 96300 Rovaniemi, Finland.
    Agbo, Friday Joseph
    School of Computing, University of Eastern Finland, 80100 Joensuu, Finland; School of Computing and Data Science, Willamette University, Salem, OR 97301, USA.
    Nyström, Markus B. T.
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Virtual Reality for Addressing Depression and Anxiety: A Bibliometric Analysis2023In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 20, no 9, article id 5621Article in journal (Refereed)
    Abstract [en]

    Virtual reality is an emerging field in mental health and has gained widespread acceptance due to its potential to treat various disorders, such as anxiety and depression. This paper presents a bibliometric analysis of virtual reality (VR) use in addressing depression and anxiety from 1995 to 2022. The study analysed 1872 documents using the Scopus database, identifying the field’s most relevant journals and authors. The results indicate that using VR for addressing anxiety and depression is a multidisciplinary field with a wide variety of research topics, leading to significant collaborative research in this area. The Annual Review of Cybertherapy and Telemedicine was identified as the most relevant journal, while Behavior Research and Therapy was found to be the most cited journal. The analysis of keywords suggests that there is more research on using VR for anxiety and related disorders than for depression. Riva G. was identified as the top author in producing research outputs on VR-AD, and the University of Washington emerged as the leading institution in scientific outputs on VR-AD. Thematic and intellectual analyses helped identify the main themes within the research domain, providing valuable insight into the current and future directions of the field.

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  • 2812.
    Jiràsek, Adam
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rizziy, Arthur
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Libm3l and lsipdx - Utilities for inter-process data transfer and synchronization2014In: 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014, American Institute of Aeronautics and Astronautics Inc. , 2014Conference paper (Refereed)
    Abstract [en]

    This paper describes two Open Source Software libraries which are currently under development - libm3l and lsipdx. The libm3l library is a utility enabling storage of the basic data types in a linked list and their transfer through the TCP/IP socket. The linked list can be transferred as a whole or just its part. The second utility, the lsipdx library, is a utility which enables transfer of the data among a number of processes and their synchronization. The libraries are therefore suitable candidate for data exchange and synchronization of a number of solvers in the multidisciplinary analysis. Both libraries are written in the ANSI-C programming language and are available to the public under GNU Lesser GPL, LGPL, license through the github site.

  • 2813.
    Joakim, Carlsson
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    CloudMAC Frame Prioritization: QoS and routing of IEEE802.11 frames in a Opendaylight controlled network2015Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Wireless networks are common in large organisations that can cover multiple floors and buildings. Wireless networks become expensive as they grow and more control and coordination is needed to operate and management them. This thesis describes how CloudMAC, a software defined networking solution (SDN), were implemented in OpenDaylight Hydrogen, a SDN controller. CloudMAC reduces complexity in large wireless local area networks. CloudMAC splits access points (AP) into, a physical (accesses the wireless medium) and a logical (handles the processing of data) part. These two part are then placed in different locations in a wired network. The parts are connected by making tunnels through the network. Some of the communications in wireless networks are time sensitive. Such time sensitive communication is easily disturbed during congestion. To improve CloudMAC, quality of service (QoS) was implemented. QoS was used both in the wired network and in accessing the wireless medium. Evaluations shows how to evaluate queues utilization and performance. 

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  • 2814. Joel, Hermansson
    et al.
    Victor, Magnusson
    Evaluation of heat sensors in public places: As an aid to the pandemic of Covid-192021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The restrictions that have been introduced with the Covid-19 pandemic has led to stores having less customers and stores shutting down. There is a need to track people's occupancy in public places so there could be more people in those places but still following the restrictions. This study evaluates and compares three different heat sensors to see if they could be used for this. The three heat sensors that have been used in this study are both low-cost and low-resolution sensors. The choice of low-resolution heat sensors is important to not intrude on people's privacy. In this study, there were three different experiments performed on all the three sensors. The experiments were done to see how sunlight could affect the sensors, what advantages, and disadvantages there are by placing the sensors in different positions, and how good the sensors are at separating people. The collected results gave a good basis to answer the research questions and better understand the sensors chosen in this research. The results also showed that the sensors can be used as an aid against a pandemic when restrictions must be kept. In the discussion we talk about how the sensors performed in different experiments and how they performed against each other. Our chosen method is also discussed and what we think were good and what went wrong so others do not repeat our mistakes. The paper ends with our conclusions and suggestions for future work.

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  • 2815.
    Joel, Jaldemark
    Halmstad University, School of Information Technology.
    Remote control of frequency inverter2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Emotron has a frequency inverter on the market that different industries uses in their factories. In case of errors they need to send out service to the factories in order to examine the inverter and find the error. They now want a solution that makes it possible for them to give support without leaving the office by connecting their devices to the cloud which eliminates the need to send out staff to industries. Emotron gave this task to HMS and has been possible with their product Anybus wiress bolt. By connecting the Anybus wireless bolt to the inverter it was possible to communicate with the cloud, MicrosoftAzure, where a static webb application is hosted. The application is made to look like the terminal on the inverter and has similiar structures and functionality. Through the application users can communicate withthe inverter by means of controlling the connected motor, reading registers and also write to certain registers. These registers contain different measurement and option parameters. The purpose of this thesis was to create a Proof-of-Concept solution using the Anybus wireless bolt. The thesis has shown of industries can use Anybus wireless bolt and the tag engine to make it possible to create a link between machines and the ever- growing cloud and is also the first part of a bigger project.

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  • 2816.
    Johansson, Alfred
    Jönköping University, School of Engineering, JTH, Computer Science and Informatics.
    Ensemble approach to code smell identification: Evaluating ensemble machine learning techniques to identify code smells within a software system2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for automated methods for identifying refactoring items is prelevent in many software projects today. Symptoms of refactoring needs is the concept of code smells within a software system. Recent studies have used single model machine learning to combat this issue. This study aims to test the possibility of improving machine learning code smell detection using ensemble methods. Therefore identifying the strongest ensemble model in the context of code smells and the relative sensitivity of the strongest perfoming ensemble identified. The ensemble models performance was studied by performing experiments using WekaNose to create datasets of code smells and Weka to train and test the models on the dataset. The datasets created was based on Qualitas Corpus curated java project. Each tested ensemble method was then compared to all the other ensembles, using f-measure, accuracy and AUC ROC scores. The tested ensemble methods were stacking, voting, bagging and boosting. The models to implement the ensemble methods with were models that previous studies had identified as strongest performer for code smell identification. The models where Jrip, J48, Naive Bayes and SMO.

    The findings showed, that compared to previous studies, bagging J48 improved results by 0.5%. And that the nominally implemented baggin of J48 in Weka follows best practices and the model where impacted negatively. However, due to the complexity of stacking and voting ensembles further work is needed regarding stacking and voting ensemble models in the context of code smell identification.

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  • 2817.
    Johansson, Alfred
    University of Skövde, School of Informatics.
    HTTP Load Balancing Performance Evaluation of HAProxy, NGINX, Traefik and Envoy with the Round-Robin Algorithm2022Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Operating a popular website is a challenging task. Users not only expect services to always be available, but also good performance in the form of fast response times. To achieve high availability and avoid performance problems which can be linked to user satisfaction and financial losses, the ability to balance web server traffic between servers is an important aspect.

    This study is aimed to evaluate performance aspects of popular open-source load balancing software working at the HTTP layer. The study includes the well-known load balancers HAProxy and NGINX but also Traefik and Envoy which have become popular more recently by offering native integration with container orchestrators. To find performance differences, an experiment was designed with two load scenarios using Apache JMeter to measure the throughput of requests and response times with a varying number of simulated users.

    The experiment was able to consistently show performance differences between the software in both scenarios. It was found that HAProxy overall had the best performance in both scenarios and could handle test cases with 1000 users where the other load balancers began generating a large proportion of failed connections significantly better. NGINX was the slowest when considering all test cases from both scenarios. Averaging results from both load scenarios excluding tests at the highest, 1000 users, concurrency level, Traefik performed 24% better, Envoy 27% better and HAProxy 36% better compared to NGINX.

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  • 2818.
    Johansson, Anders
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Global Industrial Development, Scania CV AB, Södertälje.
    Money talks while volume and value should run the show: An evaluation of financial parameters for decision making duringmanufacturing system acquisition2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Market economic values have for the last decades been given an increasing role with the establishment of financial institutes and global organisations with a capitalistic focus as a consequence. As a counter reaction, the concept of sustainable development has emerged complementing the economic focus with environmental and social aspects. However, there are still challenges on how to make balanced decisions based on all three view points and consequently the decision makers still primarily reside to the established tangible financial data. Within the industrial setting there is no difference. The manufacturing system design is based on multiple criteria and requirements, but commonly the final investment decision is primarily based on what can be financially justified. Longterm solutions probably lies in combining the tangible economy with the less tangible soft values that cannot be valued in monetary means. Therefore, to find this sweet spot, the purpose of this research is to in-depth investigate the world of economy, but from an engineers' point of view. A financial analysis is done to understand the economical components and how these are related to the manufacturing system. Furthermore, to connect cost with contributed value of the manufacturing system, a holistic business value chain analysis is done to ensure that less tangible aspects can be understood and utilised. The result of this research, highlights for example that sales volume has a larger impact on the manufacturing profitability, than that of the initial investment cost. Therefore, manufacturing systems should also be evaluated on the bases of how well it can meet the volatility in market demands. Another result presented is a portfolio of new graphical representation used as a support tool for investment decisions. Furthermore, to be able to invest in manufacturing systems that contribute to a more competitive company, the wider business value with manufacturing is discussed.

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  • 2819.
    Johansson, Anders
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Global Industrial Development, Scania CV AB, Södertälje.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Production Systems.
    Pejryd, Lars
    School of Science and Technology, Örebro University.
    Manufacturing System Design for Business Value, a Holistic Design Approach2016In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 50, p. 659-664Article in journal (Refereed)
    Abstract [en]

    When designing and developing manufacturing systems, many aspects need to be considered. Typically, the manufacturing design objectives are specified to achieve certain operational requirements around quality, capacity, cost etc. They are also specified withthe intention to ensure efficient processes related to manufacturing, such as maintenance, logistics, not to mention the main process of manufacturing the actual part. This study proposes that a wider company perspective should be considered during manufacturing system design, to achieve a greater business value. The manufacturing system should be designed to create value to other core business processes, such as product development, marketing, sales and services. This paper also presents examples on value perspectives to consider and how this approach can be implemented.

  • 2820.
    Johansson, Anders
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Global Industrial Development, Scania CV AB, Södertälje.
    Pejryd, Lars
    School of Science and Technology, Örebro University.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Production Systems.
    Production support model to manage market demand volatility risks2016In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 57C, p. 664-668Article in journal (Refereed)
    Abstract [en]

    In the investment selection process during the design of new manufacturing systems, both the technical attributes and the expected financial performance need to be evaluated. To manage the financial risks with market volatility, it is important to understand the composition of fixed and variable cost factors in relation to the expected volume interval. The support model developed in this paper will in a simple and intuitive way visualise the effect on production cost due to changes in market demands. It can also be used to evaluate the volume sensitivity of existing manufacturing systems, even compare systems making different products.

  • 2821.
    Johansson, Ann
    Högskolan Väst.
    Confusions in Writing Use Cases2004In: Proceedings of the 2nd International Conference on Information Technology for Application (ICITA 2004), 2004Conference paper (Refereed)
    Abstract [en]

    Use cases are often very powerful and are popular to use when defining functional requirements for a system. UML supports the use of use cases in object-oriented systems development. However it is not always clear for systems developers on how to use use cases. It can be very confusing in knowing what to include or how to structure use cases. In this study a weather station system has been analysed with an object-oriented approach. Some problems occurred on how to structure scenarios and use cases. Problems also arose on what to describe in the use cases. The problems were analysed and assessed in this paper. The paper points out that the need for guidelines is of great importance.

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  • 2822.
    Johansson, Anna-Lena
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    Logic program synthesis using schema instantiation in an interactive environment1995Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The research presented herein proposes a method of program synthesis based on a recursive program schema and performed with an explicit incremental plan as the core of the synthesis. A partial prototype has been built in order to be able to actually perform syntheses according to the method. The presentation of the method is accompanied by examples of performed syntheses.

    The program schemata proposed are simple and based directly on the inductive definition of a data structure which is a basis for the program. The replacement rule for instantiating the schemata is also simple. The simple schema and the simple rule should make the method easy to understand.

    In situations when program sentences in a program are similar, meaning that there are similarities in their derivations, we would like, if feasible, to avoid constructing all the corresponding derivations. A method to decide when a definition yields analogous sentences and which also produces a substitution defining the analogy is presented. As a result we can replace a derivation by a substitution, making the onus of synthesis easier. The method has been implemented as a part of the system for interactive synthesis support.

    The synthesised programs are discussed with three logical concerns in mind as follows: partial correctness, completeness and totality. The synthesised normal programs are always logical consequences of the specification. Whenever the programs and their goals are definite the programs are always partially correct. From a study of the synthesis emerges a sufficient condition for programs that use negation to be partially correct and for definite or normal programs to be complete. Sufficient conditions for the derived relation to be total can be used to show that the program is defined for every element of the recursive set.

  • 2823.
    Johansson, Annie
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Att utvärdera en digital affärsidé2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete belyser tre olika organisationsteorier, PESTLE, Porter´s five forces och SWOT. En genomgång görs kring vad de olika teorierna innebär, hur de kan bidra till att förstå en organisations omvärld och dess styrkor och svagheter vilket i sin tur ger indikationer på vad man bör ha med i beräkningen när man tar strategiska beslut i en befintlig eller nystartad organisation. Teorierna används i detta fall som ett sätt att utvärdera en digital affärsidé, vad man bör ha i åtanke samt att lyfta fram dess styrkor och svagheter. På så vis har en tydlig bild skapats kring hur man kan använda sig utav de valda teorierna.

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  • 2824.
    Johansson, Anthon
    Linköping University, Department of Computer and Information Science, Human-Centered systems.
    How can Atlassian products be modified to reduce the average time usage for common tasks2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Software tools such as Build systems and project management tools are sometimes notwell designed when it comes to usability. This paper investigates the possibility of creatingcustom solutions for the three Atlassian products Jira, Confluence, and BitBucket, in orderto increase the efficiency when performing common tasks at the Atlassian administration atSaab AB. It was discovered that the main issue was performing reoccurring project-accesspermission audits, which was a very repetitive task with many manual steps involved.The solution to the issue was a Python script that, through the use of the Atlassian RESTAPI, could collect all the necessary information automatically and present it in a readablesummarized view. The amount of manual steps was significantly decreased to just a fewsteps which made a huge difference for the Atlassian administrators at Saab AB.

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  • 2825.
    Johansson, Anton
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Stenzelius, Kalle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Portning av ett Linuxbaserat system2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The project is about embedded systems in self-driving vehicles which is a growing andcurrent area. This is important as the automation of vehicles can make different sectorssuch as the mining and logistics industry more effective. This work relates to the topicas it aims to improve part of the self-driving software stack by replacing Ubuntu with aless resource-intensive Linux based system. The main goal of this work is to implementand document improvements. The work contains a research part where advantages anddisadvantages are compared against each other, followed by an implementation thatiteratively solved one problem at a time.The result became instructions and documentation describing the choices madefor a less resource demanding Linux based system. It also includes instructions anddocumentation for two different application that are part of the software stack.

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  • 2826.
    Johansson, Bjarne
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. ABB Process Automation, Process Control Platform, Västerås, Sweden.
    Rågberger, Mats
    ABB Process Automation, Process Control Platform, Västerås, Sweden.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Priority Based Ethernet Handling in Real-Time End System with Ethernet Controller Filtering2022In: IECON 2022 – 48th Annual Conference of the IEEE Industrial Electronics Society, 2022Conference paper (Refereed)
    Abstract [en]

    This work addresses the impact of best-effort traffic on network-dependent real-time functions in distributed control systems. Motivated by the increased Ethernet use in real-time dependent domains, such as the automation industry, a growth driven by Industry 4.0, interconnectivity desires, and data thirst. Ethernet allows different network-based functions to converge on one physical network infrastructure. In the automation domain, converged networks imply that functions with different criticality and real-time requirements coexist and share the same physical resources. The IEEE 60802 Time-Sensitive Networking profile for Industrial Automation targets the automation industry and addresses Ethernet network determinism on converged networks. However, the profile is still in the draft stage at the time of writing this paper. Meanwhile, Ethernet already provides attributes utilized by network equipment to prioritize time-critical communication. This paper shows that Ethernet Controller filtering with prioritized processing is a prominent solution for preserving real-time guarantees while supporting best-effort traffic. A solution capable of eliminating all best-effort traffic interference in the real-time application is exemplified and evaluated on a VxWorks system.

  • 2827.
    Johansson, Bjarne
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rågberger, Mats
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Heartbeat Bully: Failure Detection and Redundancy Role Selection for Network-Centric Controller2020In: IECON Proceedings (Industrial Electronics Conference), 2020, p. 2126-2133, article id 9254494Conference paper (Refereed)
  • 2828.
    Johansson, Björn
    et al.
    Department of Informatics, School of Economics and Management, Lund University .
    Bergkvist, Linda
    Karlstad University, Faculty of Economic Sciences, Communication and IT (discontinued), Department of Information Systems and Project Management.
    Management of Information Systems Outsourcing: Evaluation of Lessons Learned from a Boundary Spanning Perspective2012In: Electronic Journal of Information Systems Evaluation, E-ISSN 1566-6379, Vol. 15, no 1, p. 63-73Article in journal (Refereed)
    Abstract [en]

    Even if outsourcing is a well-researched phenomenon, it can be stated that evaluation studies on IS outsourcing relationships are scarce. From a description of two IS outsourcing relationship cases, a set of lessons learned are presented. A boundary spanning perspective is then used when evaluating these lessons learned in the client-supplier outsourcing relationships and thereby adding a “new” theoretical perspective on outsourcing relationships. The evaluation is concluded in a set of propositions that present the boundary spanning perspective of the lessons learned. The aim of these propositions is to act as both a guiding tool for how to further develop boundary spanning roles in outsourcing relationships and to act as a base for future research on outsourcing relationships.

  • 2829.
    Johansson, Christoffer
    et al.
    Linköping University, Department of Computer and Information Science.
    Lesicki, Dawid
    Linköping University, Department of Computer and Information Science.
    Undersökning av energiförbrukningen i låssystem2019Independent thesis Basic level (university diploma), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Genom att använda en vanlig smartphone kan hanteringen av nycklar till elektroniska dörrlås förenklas avsevärt. Phonirohar använt denna teknik till att förbättra arbetsvillkoren och rutinerna hos flertalet hemtjänstföretag över hela Skandinavien. Under en långtid har Phoniro samlat in data över hur deras kunder använder dessa elektroniska lås för att kunna hjälpa till att förbättra företagens rutiner. Den data som samlats in vill Phoniro även analysera för att kunna förbättra livstiden hos de batterier som används för att driva dörrlåsen. Denna rapport syftar till att genomföra en grundläggande analys av denna data för att kunna analysera hur olika låsinställningar påverkar energikonsumtionen och hur man kan minimera denna. Initialt i arbetet sker en genomgång av olika metoder och algoritmer för att analysera stora mängder data. De algoritmer som ansågs vara lämpliga för arbetet valdes sedan ut för att testat. De algoritmer som uppvisade ett bra resultat valdes för analys av erhållen data. De utvalda algoritmerna användes till att analysera den given data genomklassificering, klusterindelning och regression. Resultatet av denna analys påvisade att det inte var möjligt att tydligt visa vilka parametrar som gav den lägsta energiförbrukningen eller hur den påverkas av olika inställningar.

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  • 2830.
    Johansson, Cristina
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Multiobjective Optimization for Safety and Reliability Trade-off: Applications on Early Phases of Aircraft Systems Design2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A strategic issue for any industrial company is to conceive safe and reliable systems while performing all systems’ intended functions at a minimum cost. System safety and reliability are fundamental to system design and involve a quantitative assessment prior to system development. Aircraft design is a multifaceted process that involves several different disciplines, system safety and reliability among them, to obtain o holistic approach of a complex product. During the last decades, the idea of trade-off between safety or reliability goals against other characteristics has become more prominent. Furthermore, while predictions of system performance can be made in early design phases with credible precision, within reasonable tolerances, reliability and system safety are seldom predicted with high accuracy and confidence. Making the right design decisions in the early design phase is vital to the success of a project. Nowadays, it is essential within the design of new products, to increase awareness (knowledge) early in the design phases and keep the design decisions (freedom) open as long as possible, and with that also keep down the allocated costs.

    This thesis presents MOSART (Multiobjective Optimization for Safety and Reliability Trade-off), a method promoting a systematic approach regarding trade-offs between system safety and reliability goals against other contradictory targets, such as weight and cost, in early design phases.

    A theoretical framework and context are presented in the first part of the thesis, including system safety and reliability methods and optimization techniques. The second and third parts are dedicated to contributions and papers, where seven papers are included. These papers approach different aspects of MOSART, from the basic idea to the implementation and usage of the method in the conceptual phase of aircraft systems design. Several aspects regarding the choice of system safety and reliability methods in early design phases are also included in the papers, e.g. evaluation of applicability of reliability methods in early design phases, considerations around the usage of these methods within the MOSART framework and a proposal of a guideline for how to choose the right reliability method. All the examples used in the papers are chosen from basic aircraft sub-systems.

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  • 2831.
    Johansson, Cristina
    et al.
    Mendeley, Bröderna Ugglasgatan, Linköping, Sweden.
    Derelöv, Micael
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    How to use an Optimization-based Method Capable of Balancing Safety, Reliability, and Weight in an Aircraft Design Process2017In: Nuclear engineering and technology : an international journal of the Korean Nuclear Society, ISSN 1738-5733, E-ISSN 2234-358X, Vol. 49, p. 404-410Article in journal (Refereed)
    Abstract [en]

    In order to help decision-makers in the early design phase to improve and make more cost-efficient system safety and reliability baselines of aircraft design concepts, a method (Multi-objective Optimization for Safety and Reliability Trade-off) that is able to handle trade-offs such as system safety, system reliability, and other characteristics, for instance weight and cost, is used. Multi-objective Optimization for Safety and Reliability Trade-off has been developed and implemented at SAAB Aeronautics. The aim of this paper is to demonstrate how the implemented method might work to aid the selection of optimal design alternatives. The method is a three-step method: step 1 involves the modelling of each considered target, step 2 is optimization, and step 3 is the visualization and selection of results (results processing). The analysis is performed within Architecture Design and Preliminary Design steps, according to the company’s Product Development Process. The lessons learned regarding the use of the implemented trade-off method in the three cases are presented. The results are a handful of solutions, a basis to aid in the selection of a design alternative. While the implementation of the trade-off method is performed for companies, there is nothing to prevent adapting this method, with minimal modifications, for use in other industrial applications.

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  • 2832.
    Johansson, Cristina
    et al.
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Derelöv, Micael
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Bergström, B.
    SAAB Aeronautics, Linköping, Sweden.
    Nilsson-Sundén, H.
    SAAB Aeronautics, Linköping, Sweden.
    An Industrial Implementation of an Optimization Based Method for Balancing Safety, Reliability and Weight of Aircraft Systems2017In: Risk, Reliability and Safety: Innovating Theory and Practice: Proceedings of ESREL 2016 (Glasgow, Scotland, 25-29 September 2016) / [ed] Lesley Walls, Matthew Revie and Tim Bedford, CRC Press, 2017, p. 1707-1713Conference paper (Refereed)
    Abstract [en]

    The aim of this paper is to show how a method able of trade-offs such as system safety, reliability, weight and cost can be practically implemented in industry (SAAB Aeronautics). The scope is to facilitate the decision-making on the optimal design in early design phases. The method consists of several steps guiding the user to model each objective, verify and validate the models, perform optimization and finally visualize and select the results. Within the practical implementation of this method, several challenges are addressed and solved. For example, one challenge is to implement the trade-off method using the existing programs. Another challenge is the user friendliness of the implementation. In order to solve these challenges, the analysis is started and performed in Matlab. A Graphical User Interface guides the user to select the analysis to perform, budgets/requirements for each objective and parameters with influence on end-result. Data regarding the safety and reliability objectives, exported from Reliability Workbench program to Excel, is imported to Matlab, where the analysis is performed. The results are extracted into an Excel file, where the user can work further on visualization and selection. Two small examples are used to demonstrate this practical implementation of the trade-off method. Lessons learned are presented, strengths, limitations and development potential.

  • 2833.
    Johansson, Daniel
    Royal Institute of Technology ; Musiclink Hultsfred.
    An automated system for analyzing music usage and metadata exchange on digital music services2009In: eChallenges e-2009 Conference Proceedings / [ed] Paul Cunningham & Miriam Cunningham, International Information Management Corporation Limited, 2009, p. 1-9Conference paper (Refereed)
    Abstract [en]

    The study investigated music usage on several online services over a period of sixteen months with the purpose of identifying listening behaviours among fans and differences between music genres online. The research was conducted with the Music Intelligence Mashup System, a platform for automatically collecting data from online services. The study identifies large discrepancies between genres as well as a number of interesting findings on listening behaviours for particular artists. The paper also presents several suggestions for how the music industry could develop new business models in the digital environment.

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  • 2834.
    Johansson, David
    University of Skövde, School of Informatics.
    Applicability analysis of computation double entendre humor recognition with machine learning methods2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
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  • 2835. Johansson, E.
    et al.
    Gahlin, C.
    Borg, Anton
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Crime Hotspots: An Evaluation of the KDE Spatial Mapping Technique2015In: Proceedings - 2015 European Intelligence and Security Informatics Conference, EISIC 2015 / [ed] Brynielsson J.,Yap M.H., IEEE Computer Society, 2015, p. 69-74Conference paper (Refereed)
    Abstract [en]

    Residential burglaries are increasing. By visualizing patterns as spatial hotspots, law-enforcement agents can get a better understanding of crime distributions and trends. Two aspects are investigated, first, measuring the accuracy and performance of the KDE algorithm using small data sets. Secondly, investigation of the amount of crime data needed to compute accurate and reliable hotspots. The Prediction Accuracy Index is used to effectively measure the accuracy of the algorithm. The data from three geographical areas in Sweden, including Stockholm, Gothenburg and Malmö are analyzed and evaluated over a one year. The results suggest that the usage of the KDE algorithm to predict residential burglaries performs well overall when having access to enough crimes, but is capable with small data sets as well

  • 2836. Johansson, Fredrik
    Attacking the Manufacturing Execution System: Leveraging a Programmable Logic Controller on the Shop Floor2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background. Automation in production has become a necessity for producing companies to keep up with the demand created by their customers. One way to automate a process is to use a piece of hardware called a programmable logic controller (PLC). A PLC is a small computer capable of being programmed to process a set of inputs, from e.g. sensors, and create outputs, to e.g. actuators, from that. This eliminates the risk of human errors while at the same time speeding up the production rate of the now near identical products. To improve the automation process on the shop floor and the production process in general a special software system is used. This system is known as the manufacturing execution system (MES), and it is connected to the PLCs and other devices on the shop floor. The MES have different functionalities and one of these is that it can manage instructions. Theses instructions can be aimed to both employees and devices such as the PLCs. Would the MES suffer from an error, e.g. in the instructions sent to the shop floor, the company could suffer from a negative impact both economical and in reputation. Since the PLC is a computer and it is connected to the MES it might be possible to attack the system using the PLC as leverage. Objectives. Examine if it is possible to attack the MES using a PLC as the attack origin. Methods. A literature study was performed to see what types of attacks and vulnerabilities that has been disclosed related to PLCs between 2010 and 2018. Secondly a practical experiment was done, trying to perform attacks targeting the MES. Results. The results are that there are many different types of attacks and vulnerabilities that has been found related to PLCs and the attacks done in the practical experiment failed to induce negative effects in the MES used. Conclusions. The conclusion of the thesis is that two identified PLC attack techniques seems likely to be used to attack the MES layer. The methodology that was used to attack the MES layer in the practical experiment failed to affect the MES in a negative way. However, it was possible to affect the log file of the MES in one of the test cases. So, it does not rule out that other MES types are not vulnerable or that the two PLC attacks identified will not work to affect the MES.

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  • 2837.
    Johansson, Fredrik
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Microscopic Simulation of Pedestrian Traffic2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There has recently been a renewed interest in planning for pedestrian traffic, primarily in connection to public transport interchange stations, since these are important for public transport to constitute an attractive alternative to car usage. This thesis concerns microscopic simulation of pedestrian traffic, which is a promising tool for analyzing and predicting the traffic situation in a given pedestrian facility; particularly powerful when the traffic is congested. Important applications of microscopic simulation include comparison of possible infrastructure designs such as proposed interchange stations, and evaluations of various traffic management solutions, for example information systems.

    The purpose of this thesis is to advance the capabilities of pedestrian microsimulation toward a level at which it can be reliably applied for quantitative analysis by practitioners in the field. The work is based on an established microscopic model of pedestrian dynamics, the Social Force Model (sfm), and the advances are made in a number of different areas.

    To be able to evaluate and compare simulated traffic situations suitable performance measures are needed. A set of local performance measures are proposed that quantifies the local delay rate density and estimates the discomfort perceived by the pedestrians.

    The sfm is extended to include waiting pedestrians through the introduction of a waiting model, demonstrated to be stable and free from oscillations. The inclusion of waiting pedestrians in the model is critical for accurate modelling of public transport interchange stations, where large groups of waiting pedestrians may hinder passing pedestrians if the design of the station is poor.

    The relaxation time of the adaptation to the preferred velocity is an important parameter in force based models of pedestrian traffic since it affects several behaviors of the simulated pedestrians, two of which are linear acceleration and turning movements. A comparison of observations of accelerating pedestrians reported in the literature and new observations of turning pedestrians indicates that no value of the relaxation time can give model behavior consistent with both sets of observations. This indicates that modifications of the model is needed to accurately reproduce the observed behavior.

    An important input to simulations is the preferred speed of the simulated pedestrians. The common assumption that the preferred speed distribution at a location does not vary during the day is tested through observations of pedestrian traffic at Stockholm Central Station. The results demonstrate that the preferred speeds are lower in the afternoon than in the morning, implying that the preferred speed should be treated as a source of uncertainty when applying pedestrian microsimulation.

    Finally, a sensitivity analysis of a simulation of the lower hall of Stockholm Central Station is performed to find the most important sources of uncertainty in the model predictions, given the available data. The results indicate that the uncertainty related to calibration is the largest of the considered potential error sources.

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  • 2838.
    Johansson, Fredrik
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Johansson, Jörgen
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Johansson, Marcus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    IDS för alla: Intrångsdetekteringssystem för hemmaanvändare2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I dagens IT-samhälle är säkerhet en viktig aspekt. Ett sätt att nå högre säkerhet är att bygga upp säkerheten i lager. I hemmanätverk är två vanliga lager antivirus och brandvägg.

    Den här kandidatuppsatsen undersöker om ett intrångsdetekteringsystem (IDS) är ett bra komplement till säkerheten i ett hemmanätverk.För att hålla systemet så attraktivt som möjligt för hemmanätverket fokuserar man på att hålla priset nere och konfigurationen enkel. Vi valde enkorts-datorn (Raspberry Pi) med programvaran IPFire, som är open-source, där IDS:en Snort ingår och IPFire har ett enkelt gränssnitt för konfiguration.För att mäta hur effektivt systemet fungerar, mäts det hur många hot Snort upptäcker. Mätningar gjordes också för att undersöka om systemet orsakade prestandaförluster i hemmanätverket.Av resultaten drogs slutsatsen att systemet är ett bra komplement till säkerheten i ett hemmanätverk. Det gick inte att säkerställa någon prestandaförlust på nätverket förens vid en uppkoppling på 100 mbit och däröver.

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  • 2839.
    Johansson, Gustav
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Persson, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Photograph labeling application: An Android application for labeling and uploading of photographs2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The project’s goal was to solve a technical problem for Elonservice in Värmland, wheretheir technicians have the need for an upload solution for labeled photographs in connectionwith warranty claims. The solution to the problem was to develop an Android applicationthat label photographs and then automatically uploads them to a selected storage service.The end result of the project is a working Android application. Users can take photographsthrough the application and is then forced to name them in a correct manner. Theapplication automatically handles the uploading of photographs and deletion of uploadedphotographs. In addition to this there is also a gallery where all photographs are displayedwith their upload state and the opportunity to see all photos in full screen. The applicationhas future development possibilities such as more options for storage services , labelingalternative to photographs and a more attractive design.

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  • 2840.
    Johansson, Jacob
    Linköping University, Department of Computer and Information Science.
    Implementation and evaluationof the ACE DTLS framework: Reducing the authentication workload of a constrained device2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    IoT-devices are becoming more advanced and powerful than ever, and the applicationpotential is increasing rapidly. It is starting to become normal to have IoT-devices takingover mundane jobs such as controlling the climate at home, or monitoring e.g the water us-age of a household. These devices are usually constrained to be as cheap and primitive asthe task allows. Most of the time, they are only used to send collected data which only re-quires a one way secure channel. However, in order to apply updates or manage the deviceremotely, the communication has to be secured both ways. There are multiple suggestionson how a two way secure channel can be established while still operating on a constraineddevice. Each security specializes in its own area e.g privacy, scalability, or simplicity. Thispaper will describe how to implement the ACE-DTLS framework and analyze the perfor-mance with respect to energy consumption and security. While ACE-DTLS is quite simpleto implement without having to understand the complex math of a key exchange, it comeswith the cost of a high overhead in order to establish a secure two way connection. It mightnot be the best suited framework for small amount of data transfers available.

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  • 2841.
    Johansson, Jonatan
    University of Skövde, School of Informatics.
    COUNTERMEASURES AGAINST COORDINATED CYBER-ATTACKS TOWARDS POWER GRID SYSTEMS: A systematic literature study2019Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    A study on countermeasures against coordinated cyber-attacks (CCA) towards power grid systems has been carried out. A coordinated cyber-attack is a cyber-based attack where multiple attackers use multiple attack-mechanisms towards multiple targets in a coordinated fashion. The coordination is based on that the different attack-mechanisms help each other in attacking the target. A CCA is made up of different stages where each stage consists of a number of attack-mechanisms and together have a certain purpose. The different stages are used to systematically advance towards its goal, which is to compromise the operation of internal systems or to steal confidential data. For example, the first stage may be used to locate entry points at the target system, and a second stage may be used to locate vulnerable hosts by sniffing ongoing network activity to further itself towards its attack goal.     Power grids that are used to generate, transmit, and distribute electricity over large geographical areas are connected to the Internet. Within these environments, commercial IT systems have been adopted to control their electrical equipment, which poses cybersecurity risks to the power grid.     Intrusion Detection Systems (IDS) are designed provide internal network protection in case of intruders. However, state-of-the-art IDSs has been found to have certain limitations in protecting against multi-stage and slow attacks. The inadequacy of state-of-the-art IDSs for protecting against CCAs motivates the need to identify alternate countermeasures that can mitigate CCAs, when the target is a power grid system. The method of choice to address this problem in this study is a systematic literature study where 48 countermeasures were identified and assessed to which extent they are suitable to mitigate CCAs. Results suggest to follow three approaches, namely to preemptively identify technical vulnerabilities in the local system, to distribute intrusion detection hosts across a larger network for better situational awareness, and to implement new types of IDS technologies. Countermeasures with references to specific publications are also provided. The study contributes to how security operators of power grids can fulfil the requirement on cybersecurity as demanded by the NIS directive of the European Union regarding protection against CCAs.

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  • 2842.
    Johansson, Magnus
    et al.
    Stockholms universitet, Institutionen för data- och systemvetenskap.
    Verhagen, Harko
    Stockholms universitet, Institutionen för data- och systemvetenskap.
    Massively multiple online role playing games as normative multiagent systems2009In: Normative Multi-Agent Systems, Guido Boella, Pablo Noriega, Gabriella Pigozzi, and Harko Verhagen , 2009Conference paper (Other academic)
  • 2843.
    Johansson, Marcus
    Halmstad University, School of Information Technology.
    SQLite Carving och Analys: En jämförelse av metoder2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    SQLite filer används av ett flertal olika program för att spara viktig information.Information som kan vara viktig för forensiska utredningar, behovet att kunnaåterskapa SQLite filer är då ett växande bekymmer. Problemet med att återskapa SQLitefiler är att, till skillnad från andra filer så har SQLite filer inget definerat slut eller någonmarkör som visar var filen slutar. Detta arbete presenterar en ny metod att bestämmaslutet på SQLite filer och jämför denna metod mot den metod som används idag tillmesta del för att återskapa SQLite filer. För att jämföra dessa metoder utvecklades tvåprogram stpextr och blkextr. Blkextr är den metod som utvecklades under detta arbete.Stpextr visade sig vara snabbare och använda mindre arbetsminne än blkextr. Men ivissa sammanhang så kommer information gå förlorad när stpextr körs till skillnad från blkextr.

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  • 2844.
    Johansson, Marcus
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Olsson, Lukas
    Mälardalen University, School of Innovation, Design and Engineering.
    Comparative evaluation of virtualization technologies in the cloud2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The cloud has over the years become a staple of the IT industry, not only for storage purposes, but for services, platforms and infrastructures. A key component of the cloud is virtualization and the fluidity it makes possible, allowing resources to be utilized more efficiently and services to be relocated more easily when needed. Virtual machine technology, consisting of a hypervisor managing several guest systems has been the method for achieving this virtualization, but container technology, a lightweight virtualization method running directly on the host without a classic hypervisor, has been making headway in recent years. This report investigates the differences between VM’s (Virtual Machines) and containers, comparing the two in relevant areas. The software chosen for this comparison are KVM as VM hypervisor, and Docker as container platform, both run on Linux as the underlying host system. The work conducted for this report compares efficiency in common use areas through experimental evidence, and also evaluates differences in design through study of relevant literature. The results are then discussed and weighed to provide a conclusion.

    The results of this work shows that Docker has the capability to potentially take over the role as the main virtualization technology in the coming years, providing some of its current shortcomings are addressed and improved upon.

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  • 2845.
    Johansson, Mathias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Artificial Intelligence.
    Lindberg, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Artificial Intelligence.
    Importance sampling in deep learning: A broad investigation on importance sampling performance2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Available computing resources play a large part in enabling the training of modern deep neural networks to complete complex computer vision tasks. Improving the efficiency with which this computational power is utilized is highly important for enterprises to improve their networks rapidly.

    The first few training iterations over the data set often result in substantial gradients from seeing the samples and quick improvements in the network. At later stages, most of the training time is spent on samples that produce tiny gradient updates and are already properly handled. To make neural network training more efficient, researchers have used methods that give more attention to the samples that still produce relatively large gradient updates for the network. The methods used are called ''Importance Sampling''. When used, it reduces the variance in sampling and concentrates the training on the more informative examples.

    This thesis contributes to the studies on importance sampling by investigating its effectiveness in different contexts. In comparison to other studies, we more extensively examine image classification by exploring different network architectures over a wide range of parameter counts. Similar to earlier studies, we apply several ways of doing importance sampling across several datasets. While most previous research on importance sampling strategies applies it to image classification, our research aims at generalizing the results by applying it to object detection problems on top of image classification.

    Our research on image classification tasks conclusively suggests that importance sampling can speed up the training of deep neural networks. When performance in convergence is the vital metric, our importance sampling methods show mixed results. For the object detection tasks, preliminary experiments have been conducted. However, the findings lack enough data to demonstrate the effectiveness of importance sampling in object detection conclusively.

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  • 2846.
    Johansson, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Mobilitet och säkerhet i ett litet företag2019Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report describes a simple implementation of an IT-strategy in a small company involving the areas of mobility, security and backup. As well as keeping in mind what kind of needs the company has in terms of number of employees and getting a cost-effective and user friendly solution. The goal is to implement a way to access an office computer securely from any network. This was achieved by evaluating different solutions that uses VPN, RPD and VNC technologies. Improving the overall security on different devices and planning a redundant backup solution that uses encryption standards such as AES.


  • 2847.
    Johansson, Oscar
    Linköping University, Department of Computer and Information Science.
    Weight Estimation and Evaluation of User Suggestions in Mobile Browsing2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study investigates the suggestion system of a mobile browser. The goal of a suggestion system is to assist the user by presenting relevant suggestions in an ordered list. By weighting the different types of suggestions presented to the user, such as history, bookmarks etc., it is investigated how this affects the performance of the suggestion sys- tem. The performance is measured using the position, error and Mean Reciprocal Rank of the chosen suggestion as well as the number of written characters. It is also measured if the user chose to not use the suggestion system, by searching or entering the entire URL. The weights were estimated using a Genetic Algorithm. The evaluation was done by performing an A/B test, were the control group used an unweighted system and the test group used the weights estimated by the genetic algorithm. The results from the A/B test were statistically analyzed using BEST and Bootstrap. The results showed an improvement of position, number of written characters, MMR and the error. There was no change in how much the user used the suggestion system. The thesis concluded that there is a correlation between the position of the desired suggestion and when the user stops typing, and that weighting types is a way to improve said position. The thesis also concludes that there is a need for future work in regards to evaluation of the optimization algorithm and error measurement.

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  • 2848.
    Johansson, Oscar
    et al.
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM), Department of Computer Science.
    Forsman, Max
    Shared computer systems and groupware development: Escaping the personal computer paradigm2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For the majority of the computers existence, we humans have interacted with them in a similar way, usually with a strict one-to-one relationship between user and machine. This is reflected by the design of most computers, operating systems and user applications on the market today, which are typically intended to only be operated by a single user. When computers are used for teamwork and cooperation, this design philosophy can be restricting and problematic. This paper investigates the development of shared software intended for multiple users and the impact of the single user bias in this context. A prototype software system was developed in order to evaluate different development methods for shared applications and discover potential challenges and limitations with this kind of software. It was found that the development of applications for multiple users can be severely limited by the target operating system and hardware platform. The authors conclude that new platforms are required to develop shared software more efficiently. These platforms should be tailored to provide robust support for multiple concurrent users. This work was carried out together with SAAB Air Traffic Management in Växjö, Sweden and is a bachelor's thesis in computer engineering at Linnaeus University.

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    Shared computer systems and groupware development
  • 2849.
    Johansson, Pierre Eric Christian
    et al.
    Volvo Group Trucks Operations.
    Malmsköld, Lennart
    University West, Department of Engineering Science, Division of Production Systems.
    Fast-Berglund, Åsa
    Chalmers University of Technology, Göteborg, Sweden.
    Moestam, Lena
    Volvo, Gothenburg, Sweden.
    Challenges of handling assembly information in global manufacturing companies2019In: Journal of Manufacturing Technology Management, ISSN 1741-038X, E-ISSN 1758-7786, Vol. 31, no 5, p. 955-976Article in journal (Refereed)
    Abstract [en]

    Purpose

    The purpose of this paper is to describe challenges the manufacturing industry is currently facing when developing future assembly information systems. More specific, this paper focuses on the handling of assembly information from manufacturing engineering to the shop floor operators.

    Design/methodology/approach

    Multiple case studies have been conducted within one case company between 2014 and 2017. To broaden the perspective, interviews with additionally 17 large and global manufacturing companies and 3 industry experts have been held. Semi-structured interviews have been the main data collection method alongside observations and web questionnaires.

    Findings

    Six focus areas have been defined which address important challenges in the manufacturing industry. For manual assembly intense manufacturing company, challenges such as IT challenges, process challenges, assembly process disturbances, information availability, technology and process control, and assembly work instructions have been identified and hinder implementation of Industry 4.0 (I4.0).

    Originality/value

    This longitudinal study provides a current state analysis of the challenges the manufacturing industry is facing when handling assembly information. Despite the vast amount of initiatives within I4.0 and digitalization, this paper argues that the manufacturing industry needs to address the six defined focus areas to become more flexible and prepared for the transition toward a digitalized manufacturing industry.

  • 2850.
    Johansson, Robin
    Mälardalen University, School of Innovation, Design and Engineering.
    NSGA-II DESIGN FOR FEATURE SELECTION IN EEG CLASSIFICATION RELATED TO MOTOR IMAGERY2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Feature selection is an important step regarding Electroencephalogram (EEG) classification, for a Brain-Computer Interface (BCI) systems, related to Motor Imagery (MI), due to large amount of features, and few samples. This makes the classification process computationally expensive, and limits the BCI systems real-time applicability. One solution to this problem, is to introduce a feature selection step, to reduce the number of features before classification. The problem that needs to be solved, is that by reducing the number of features, the classification accuracy suffers. Many studies propose Genetic Algorithms (GA), as solutions for feature selection problems, with Non-Dominated Sorting Genetic Algorithm II (NSGA-II) being one of the most widely used GAs in this regard. There are many different configurations applicable to GAs, specifically different combinations of individual representations, breeding operators, and objective functions. This study evaluates different combinations of representations, selection, and crossover operators, to see how different combinations perform regarding accuracy, and feature reduction, for EEG classification relating to MI. In total, 24 NSGA-II combinations were evaluated, combined with three different objective functions, on six subjects. Results shows that the breeding operators have little impact on both the average accuracy, and feature reduction. However, the individual representation, and objective function does, with a hierarchical, and an integer-based representation, achieved the most promising results regarding representations, while Pearson’s Correlation Feature Selection, combined with k-Nearest Neighbors, or Feature Reduction, obtained the most significant results regarding objective functions. These combinations were evaluated with five classifiers, where Linear Discriminant Analysis, Support Vector Machine (linear kernel), and Artificial Neural Network produced the highest, and most consistent accuracies. These results can help future studies develop their GAs, and selecting classifiers, regarding feature selection, in EEG-based MI classification, for BCI systems.

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    NSGA-II DESIGN FOR FEATURE SELECTION IN EEG CLASSIFICATION RELATED TO MOTOR IMAGERY
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