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  • 1.
    Abbaspour Asadollah, Sara
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Inam, Rafia
    Ericsson AB, Kista, Sweden.
    Hansson, Hans
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A Survey on Testing for Cyber Physical System2015In: Testing Software and Systems: 27th IFIP WG 6.1 International Conference, ICTSS 2015, Sharjah and Dubai, United Arab Emirates, November 23-25, 2015, Proceedings, 2015, p. 194-207Conference paper (Refereed)
    Abstract [en]

    Cyber Physical Systems (CPS) bridge the cyber-world of computing and communications with the physical world and require development of secure and reliable software. It asserts a big challenge not only on testing and verifying the correctness of all physical and cyber components of such big systems, but also on integration of these components. This paper develops a categorization of multiple levels of testing required to test CPS and makes a comparison of these levels with the levels of software testing based on the V-model. It presents a detailed state-of-the-art survey on the testing approaches performed on the CPS. Further, it provides challenges in CPS testing.

  • 2.
    Abbaspour, Sara
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fallah, Ali
    Amirkabir University of Technology, Tehran, Iran.
    Lindén, Maria
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Gholamhosseini, Hamid
    Auckland University of Technology, Auckland, New Zealand.
    A Novel Approach for Removing ECG Interferences from Surface EMG signals Using a Combined ANFIS and Wavelet2016In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 26, p. 52-59Article in journal (Refereed)
    Abstract [en]

    In recent years, the removal of electrocardiogram (ECG) interferences from electromyogram (EMG) signals has been given large consideration. Where the quality of EMG signal is of interest, it is important to remove ECG interferences from EMG signals. In this paper, an efficient method based on a combination of adaptive neuro-fuzzy inference system (ANFIS) and wavelet transform is proposed to effectively eliminate ECG interferences from surface EMG signals. The proposed approach is compared with other common methods such as high-pass filter, artificial neural network, adaptive noise canceller, wavelet transform, subtraction method and ANFIS. It is found that the performance of the proposed ANFIS-wavelet method is superior to the other methods with the signal to noise ratio and relative error of 14.97 dB and 0.02 respectively and a significantly higher correlation coefficient (p < 0.05).

  • 3.
    Alderisi, Giuliana
    et al.
    University of Catania, Catania, Italy.
    Girs, Svetlana
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lo Bello, Lucia
    University of Catania, Catania, Italy.
    Uhlemann, Elisabeth
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Björkman, Mats
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Probabilistic Scheduling and Adaptive Relaying for WirelessHART Networks2015In: 20th IEEE International Conference on Emerging Technologies and Factory Automation ETFA'15, 2015Conference paper (Refereed)
    Abstract [en]

    This paper deals with a way to probabilistically guarantee reliable packet delivery in WirelessHART based networks suitable for industrial control systems. We propose a new scheduling scheme, called Iterative Probabilistic Scheduling with Adaptive Relaying (IPS-AR), which consists of a static part (IPS) and a dynamic part (AR). IPS takes into account the channel characteristics and exploits relaying to achieve a minimum reliability threshold as requested by the supported industrial application. In the AR part, each relay node decides the packet to be sent based on online assessment of both the number of consecutive errors experienced by previous packets belonging to the same flow, as well as the number of copies of the packet currently available at the other relay nodes. This enables IPS-AR to achieve the desired reliability level while using the available re-sources in terms of time and bandwidth more efficiently.

  • 4.
    Avelin, Anders
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Widarsson, Björn
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dahlquist, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Lilja, Reijo
    VTT, Espoo, Finland.
    Time based data reconciliation and decision support for a CFB boiler2009In: IFAC Proceedings Volumes (IFAC-PapersOnline), 2009 / [ed] Yrjö Majanne, Tampere: Tampere University Press , 2009, p. 338-343Conference paper (Refereed)
    Abstract [en]

    This paper covers a method for operator decision support, where physical simulation models are used to connect different physical variables to each other. By comparing energy and material balances for a larger process area inconsistencies in single process parts and sensor measurements can be detected, by following the development between single measurements and values predicted from the simulations. This information then can be used as input to e.g. a BN, Bayesian Network, for decision support. The application has been for a CFB boiler at Mälarenergi AB. The simulators have been made in Modelica respectively a more advanced model in APROS.

  • 5.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dasari, Dakshina
    Research and Technology Centre, Robert Bosch, India.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Analyzing End-to-End Delays in Automotive Systems at Various Levels of Timing Information2016In: IEEE 4th International Workshop on Real-Time Computing and Distributed systems in Emerging Applications REACTION'16, Porto, Portugal, 2016Conference paper (Refereed)
    Abstract [en]

    Software design for automotive systems is highly complex due to the presence of strict data age constraints for event chains in addition to task specific requirements. These age constraints define the maximum time for the propagation of data through an event chain consisting of independently triggered tasks. Tasks in event chains can have different periods, introducing over- and under-sampling effects, which additionally aggravates their timing analysis. Furthermore, different functionality in these systems, is developed by different suppliers before the final system integration on the ECU. The software itself is developed in a hardware agnostic manner and this uncertainty and limited information at the early design phases may not allow effective analysis of end-to-end delays during that phase. In this paper, we present a method to compute end-to-end delays given the information available in the design phases, thereby enabling timing analysis throughout the development process. The presented methods are evaluated with extensive experiments where the decreasing pessimism with increasing system information is shown.

  • 6.
    Björkman, Patrik
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Odens Hedman, Lars
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of a collision avoidance system for a videoconferencing robot.2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The work presented in this paper is about the development of a collision avoidance systemfor a mobile telepresence robot developed by the company Gira technologies AB.The robot is designed to extend the length of time elderly can stay in their homes beforerequiring full-time staed care. The collision avoidance system is needed to help the userto avoid running in to objects or down a stairway. The design must be capable of beingimplemented at low cost, and should not look overtly "robotic" as this would not resultin an appealing industrial design.

    Herein, dierent techniques are presented and analyzed to nd the best suitable solutionfor the robot. In particular a lot of work is done in taking measurements to nd theright characteristics for the sensors according dierent mounting angles, dierent objectsand distances. A solution is chosen and calculations are made to nd the best positionsto place the sensors to get the best results.

    A complete solution is presented and implemented in the current system and testedto work as expected.

  • 7.
    Bonner, R.
    et al.
    Griffith University, AUSTRALIA .
    Sanzogni, L.
    Griffith University, AUSTRALIA .
    Vaccaro, J.
    The Open University, U.K .
    Solving the triangulation problem in real time with an imbedded neural network1996In: Proc. 8th International Conference on Artificial Intelligence Applications (EXPERSYS'96): Paris, 1996, 1996, p. 75-80Conference paper (Refereed)
  • 8.
    Bucaioni, Alessio
    Mälardalen University, School of Innovation, Design and Engineering.
    Bidirectionality in Model-Driven Engineering2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In Model-Driven Engineering bidirectional model transformations emerged as an important ingredient to cope with scenarios such as change propagation, synchronization and to keep consistent system views whenever changes occurring on some view have to be propagated over the others. However, bidirectional mappings open a number of intricate issues that have been only partially solved by research.

    This master thesis identifies a set of features characterizing bidirectional transformations and validates them against two existing approaches. In particular, a benchmark based on the UML2RDBMS transformation and consisting of two different configurations is implemented by means of two different approaches, such as Triple Graph Grammars and the Janus Transformation Language, for understanding bidirectional transformations with respect to the elicited features.

  • 9.
    Campillo, Javier
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    From Passive to Active Electric Distribution Networks2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Large penetration of distributed generation from variable renewable energy sources, increased consumption flexibility on the demand side and the electrification of transportation pose great challenges to existing and future electric distribution networks. This thesis studies the roles of several actors involved in electric distribution systems through electricity consumption data analysis and simulation models. Results show that real-time electricity pricing adoption in the residential sector offers economic benefits for end consumers. This occurs even without the adoption of demand-side management strategies, while real-time pricing also brings new opportunities for increasing consumption flexibility. This flexibility will play a critical role in the electrification of transportation, where scheduled charging will be required to allow large penetration of EVs without compromising the network's reliability and to minimize upgrades on the existing grid. All these issues add significant complexity to the existing infrastructure and conventional passive components are no longer sufficient to guarantee safe and reliable network operation. Active distribution networks are therefore required, and consequently robust and flexible modelling and simulation computational tools are needed for their optimal design and control. The modelling approach presented in this thesis offers a viable solution by using an equation-based object-oriented language that allows developing open source network component models that can be shared and used unambiguously across different simulation environments. 

  • 10.
    Campillo, Javier
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Vassileva, Iana
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Economic Impact of Dynamic Electricity Pricing Mechanisms Adoption fo rHouseholds in Sweden2013Conference paper (Refereed)
    Abstract [en]

    Global smart metering market growth has increased significantly over the past few years and the trend is expected to continue. Smart metering technology enables energy consumption feedback and the adoption of dynamic pricing mechanisms that encourages users to shift power consumption from peak-use times to lower-use times, in order to help balance the load in the power system. In Sweden particularly, the introduction of the new legislation and adoption of remote meters in 2009, in combination with more flexible pricing schemes, offer a great opportunity for users to reduce energy consumption during peak times, increase their energy efficiency and therefore reduce their overall cost. More recently, in 2012, Swedish energy providers started offering hourly spot-based electricity price to homeowners in order give them access to pricing mechanisms that are closer to the real cost of electricity supply. Additionally to hourly pricing, other dynamic pricing contracts are available for consumers all across the country; however, conventional agreements that use fixed-rates for electricity are still the most common. This paper analyzes the economic impact for consumers, if dynamic pricing, enabled through smart metering technologies, is adopted. To achieve this, electricity costs from a large group of households were calculated, using users’ hourly consumption data with both conventional fixed rates and real time pricing, in order to understand their impact on customers’ bills. Obtained results suggest that real time pricing has great savings potential, especially for years where summer rainfall and winter conditions are within average. However, in order to increase savings and have them consistent year after year, changes in user time-of-use consumption profile are required. Moreover, this research work leads to further analysis on dynamic pricing combined with demand response in order to optimize electricity costs.

  • 11.
    CANOVAS CAMINO, FRANCISCO
    Mälardalen University, School of Innovation, Design and Engineering.
    An Intelligent Portable Sensor System in Diagnosing Stress2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays stress is a frequent problem in the society. Stress level could be important in order torecognise health problems later.Electrocardiogram technics allows to supervise the heart condition and the detection ofanomalies about the patient.Sometimes data collection systems by sensors placed on the patient restrict his mobility.Therefore the elimination of wires is a good solution for this trouble. Then the Bluetooth protocol ischosen as way for transmitting and receiving data between stations. There are three ECG sensorsplaced on the right hand, the left hand and the right leg. It is possible to measure the heart signalwith this technique. Besides there is an extra sensor in order to measure the temperature of thepatient. Depending of the value of these parameters is possible to recognise stress levels. Allsensors are connected to a special box with a microcontroller which treats every signal. Thismodule has a Bluetooth part that transmitts wireless the new digital signal to the receiver. This onewill be a dongle connected to the computer by Serial Port.A program in the computer has been implemented in order to receive the Bluetooth Datasent from the box and saving the data in a file for subsequent activities.

  • 12.
    Casal, Alexander
    Mälardalen University, School of Innovation, Design and Engineering.
    Om Elbolags Hantering av Reaktiv Effekt och Elavbrott med avseende på Hushållskunder2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Elvabrott och reaktiv effekt är två faktorer som förorsakar stora överkostnader vid samtliga elbolag. Dessa kostnader överförs i sinom tid till kunderna.Samtidigt mer och mer regler och normer kräver större tillsynt för kundernas fördel. Kostnaderna bör optimeras och information bli tillgängligare. Installationen av de nya fjärravläsningssystemen öppnar nya möjligheter för att förbättra dessa processer.Syftet med detta arbete är att undersöka och analysera processer och procedurer i tre elbolag för att hantera reaktiv effekt hos privatkunder och elavbrott.Resultatet visar att elbolagen är mycket konservativa med sina processer och fortfarande finns utrymme för flera förbättringar. Reaktiv effekt tas inte i beaktande och underskattas ordentligt av elbolag hos vanliga hushåll. Trots detta några försök att börja arbeta med den har redan införts. Däremot reaktiv effekt hos stora konsumenter och industri är med i detta arbete endast som ett exempel därför att där finns det omfattande kontroller och kompenseringar. Fokus i vårt fall ligger på hushåll.Angående elavbrott finns väl bestämda mekanismer. Analysen visar att det finns möjlighet att förbättra dessa processer genom att utnyttja de nya fjärravläsningsmätarna, GIS- och GPS-system.Det presenteras några lösningar där det anses vara nödvändigt men inte i den stora hela. Målet är att undersöka och beskriva processer inför framtida arbeten.

  • 13.
    Causevic, Azra
    Mälardalen University, School of Innovation, Design and Engineering.
    Data Dependency Analysis in Industrial Systems2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Software in modern industrial systems may have complex data dependencies. As a result of this, it can be hard for system developers to understand the system’s behavior, if they cannot explicitly see these dependencies. This thesis addresses this problem, with an emphasis on dependencies among data in systems built using the IEC 61499 standard. An analysis method was developed, with which we are able to extract data dependency information from basic and composite function blocks. The first step of handling this problem is to investigate how the data dependencies occur in IEC 61499. The second step is to create a formal definition of IEC 61499 elements that were needed in order to formulate the analysis method. Next, we define a dependency matrix, in which we store the information regarding dependencies between input and output data ports. Later, we formulate the necessary algorithms for data dependency analysis in basic and composite function blocks. Finally, the last piece of the puzzle is to develop a plug-in for Framework for Distributed Industrial Automation and Control – Integrated Development Environment. This plug-in is used to show that the analysis method is efficient and that the proposed analysis is applicable to IEC 61499 systems.

  • 14.
    Dahlquist, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    HOW TO MAKE A REGION FOSSIL FUEL FREE – ENERGY CONSERVATION COMBINED WITH BIOGAS PRODUCTION FROM CROPS AND WASTE2010In: 5th International Ege Energy Symposium and Exhibition (IEESE-5), 27-30 June 2010, Pamukkale University, Denizli, Turkey / [ed] Ibrahim Dincer, 2010Conference paper (Refereed)
    Abstract [en]

    In Malardalen, Sweden a work is on-going to drive the region towards becoming fossil fuel free. To get rid of coal a decision has been made to build a waste combustion plant. The plant will have a fuel capacity of 200 MW thermal. There are also a number of biogas plants. One is recycling all the organic waste in the region, and combining with crop residues from the farmers. With planned expansions we will produce some 7 million Nm3/y, corresponding to some 9-10 MW HHV. This would make a total of some 500 GWh/y. Today the total consumption of fuels for vehicles is 2 TWh. With new technologies for cars and other vehicles we could take the consumption down to at least some 1 TWh/y. The methane then would cover 50% of the need. To this we add some 0.25 TWh extra electricity for cars used primarily in cities. Possibilities to reduce energy consumption and build renewable power like wind and solar power for both Sweden and EU27 is also discussed, where a special emphasis is made on possibilities to reduce energy consumption in process industries like metal, pulp and paper and cement. This includes increasing production efficiency by using on-line applications of simulation models. This also includes power plants. The conclusion is that it is possible to reach a balance in Malardalen region including Stockholm, and with a total of 3 million people, but also all Sweden.

  • 15.
    Dersten, Sara
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Finding critical architectural decisisons for autonomous vehicle product-lines2014In: The 40th Euromicro Conference on Software Engineering and Advanced Applications SEAA 2014, 2014Conference paper (Refereed)
  • 16.
    Fard, Ali
    Mälardalen University, Department of Computer Science and Electronics.
    Analysis and Design of Low-Phase-Noise Integrated Voltage-Controlled Oscillators for Wide-Band RF Front-Ends2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The explosive development of wireless communication services creates a demand for more flexible and cost-effective communication systems that offer higher data rates. The obvious trend towards small-size and ultra low power systems, in combination with the ever increasing number of applications integrated in a single portable device, tightens the design constraints at hardware and software level. The integration of current mobile systems with the third generation systems exemplifies and emphasizes the need of monolithic multi-band transceivers. A long term goal is a software defined radio, where several communication standards and applications are embedded and reconfigured by software. This motivates the need for highly flexible and reconfigurable analog radio frequency (RF) circuits that can be fully integrated in standard low-cost complementary metal-oxide-semiconductor (CMOS) technologies.

    In this thesis, the Voltage-Controlled Oscillator (VCO), one of the main challenging RF circuits within a transceiver, is investigated for today’s and future communication systems. The contributions from this work may be divided into two parts. The first part exploits the possibility and design related issues of wide-band reconfigurable integrated VCOs in CMOS technologies. Aspects such as frequency tuning, power dissipation and phase noise performance are studied and design oriented techniques for wide-band circuit solutions are proposed. For demonstration of these investigations several fully functional wide-band multi-GHz VCOs are implemented and characterized in a 0.18µm CMOS technology.

    The second part of the thesis concerns theoretical analysis of phase noise in VCOs. Due to the complex process of conversion from component noise to phase noise, computer aided methods or advanced circuit simulators are usually used for evaluation and prediction of phase noise. As a consequence, the fundamental properties of different noise sources and their impact on phase noise in commonly adopted VCO topologies have so far not been completely described. This in turn makes the optimization process of integrated VCOs a very complex task. To aid the design and to provide a deeper understanding of the phase noise mechanism, a new approach based on a linear time-variant model is proposed in this work. The theory allows for derivation of analytic expressions for phase noise, thereby, providing excellent insight on how to minimize and optimize phase noise in oscillators as a function of circuit related parameters. Moreover, it enables a fair performance comparison of different oscillator topologies in order to ascertain which structure is most suitable depending on the application of interest. The proposed method is verified with very good agreement against both advanced circuit simulations and measurements in CMOS and bipolar technologies. As a final contribution, using the knowledge gained from the theoretical analysis, a fully integrated 0.35µm CMOS VCO with superior phase noise performance and power dissipation is demonstrated.

  • 17.
    Folke, Mia
    Mälardalen University, Department of Computer Science and Electronics.
    Measurements of Respiratory Carbon Dioxide2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [sv]

    Koldioxid är en central parameter för metabolismen i alla levande varelser. Hos människan regleras koldioxidhalten främst genom andningen. Därför är det viktigt att kunna mäta och övervaka koldioxidhalten i fysiologiska applikationer så väl inom sportmedicin som inom vården, till exempel på intensivvårdsavdelningar. Dessa mätningar kräver adekvat mätutrustning.

    Syftet med denna avhandling är att kritiskt granska föreslagna metoder för övervakning av andningsaktiviteten, att föreslå och utveckla förbättringar, samt att föreslå och utveckla nya applikationer för mätning av koldioxidhalten i utandningsluften med hjälp av en elektroakustisk sensor.

    Mätning av koldioxid i utandningsluften har den fördelen över andra föreslagna metoder för andningsövervakning att den även ger information om förhållandet i arteriellt blod då partialtrycket för koldioxid i slutet av ett andetag är lika stort som i artärblod hos lungfriska personer.

    Den föreslagna tekniken bygger på en elektroakustisk sensor som kan registrera och mäta koldioxidhalten i utandningsluften om fukt- och temperaturvariationer utjämnas med hjälp av filter. Den elektroakustiska sensorn består av en ultraljudssändare och en reflektor placerade i varsin ände av ett perforerat rör. Den elektriska impedansen i sensorn representerar molekylvikten inne i sensorkaviteten. Molekylmassan har ett linjärt förhållande till koldioxidhalten så länge övriga gaser hålls konstanta.

    Det faktum att partialtrycket av koldioxid i slutet av ett andetag kan mätas med den elektroakustiska sensorn gör den användbar i flera kliniska situationer om andra gaser inte kan påverka mätningarna.

    Partialtrycket av koldioxid i slutet av ett andetag har visat sig vara användbar som en indikator för mjölksyratröskeln då personens individuella mjölksyratröskel infaller då partialtrycket av koldioxid i slutet av ett andetag börjar minska. Det ger en ny applikation inom sportmedicin. På det sättet är det möjligt för en idrottare att mäta variationerna i sin mjölksyratröskel, i sin egen sport på daglig basis, vilket kan användas för att optimera arbetsintensiteten under träning och tävling. Trots att det elektroakustiska sensorsystemet inte är selektivt för koldioxid och därför påverkas även av förändringar i syre i utandningsluften har det visat sig fungera i denna applikation.

  • 18.
    Forsberg, Mattias
    Mälardalen University, School of Innovation, Design and Engineering.
    Trådlös bränsletrycksövervakning2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    På bilar med insprutningsmotorer behövs oftast någon typ av justering av bränsletryck då olika typer av belastning behöver olika mycket bränsle. Mängden bränsle motorn får styrs till viss del av spridarnas öppentider samt storleken på spridarmunstyckena. Men öppentiderna kan inte vara hur långa som helst samt storleken på spridarmunstyckena kan inte vara allt för stor heller då man bara har en viss tid på sig att trycka in bränsle under insugstakten[1] samt att man inte vill trycka in allt för mycket bränsle heller beroende på belastningen på motorn. Just för den anledningen används oftasten bränsletrycksregulator för sänka bränsletrycket när belastningen är låg och höja bränsletrycket när belastningen är hög. De flesta bränsletrycksregulatorer som sitter som standard på bilar är inte justerbara utan har oftast bara ett fast arbetsområde som styrs med hjälp av vakuum. Börjar man ta ut mer effekt ur en motor kommer det att behövas mer bränsle och ett sätt att få in mer bränsle men ändå behålla spridare och bränslepump är att byta ut den fasta bränsletrycksregulatorn mot en justerbar vilket innebär att man kan ändra arbetsområdet för bränsletrycket och därigenom få in mer bränsle under samma öppentid på spridare, vilket kan behövas vid t.ex överladdning. Den här rapporten kommer gå igenom hur ett trådlöst övervakningssystem för kontroll av bränsletryck kan konstrueras.

  • 19.
    Foskolos, Georgios
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Lennerhag, Oscar
    Independent Insulation Group, Ludvika, Sweden.
    Ackeby, Susanne
    DNV-GL Energy, Göteborg, Sweden.
    Evaluation of conservation voltage reduction - a comparison based method2018In: 2018 53rd International Universities Power Engineering Conference (UPEC), Proceedings, IEEE, 2018, p. 1-5, article id 474Conference paper (Refereed)
    Abstract [en]

    Conservation voltage reduction (CVR) is based onthe premise that conserving energy by reducing voltage levels of the electrical system will lead to reduced electrical energy consumption. In this work a comparison-based method has been applied for assessing CVR effects in a distribution grid. The reference voltage on the secondary side of the primary substation was manually altered according to a predefined schedule during 6 months, that is, perform CVR on a substation and apply “normal” voltage to the same substation with a 2-week interval between the changes. Measurements (1 second RMS-values for voltages, active powers and reactive powers) and analysis were made at the 11 kV side of a 130/11 kV transformer of a primary substation, on outgoing feeders and at the 400 V side of 11/0.4 kV distribution transformers downstream of the primary substation as well as on downstream single rural and industrial customers. Active power at different reference voltage levels versus 24 hours divided into 10 minute intervals for reoccurring days of the week were plotted and analysed.

    This work confirms the difficulties in obtaining predictable loads over time and to accurately analyse the load composition on all grid levels. Each are needed in order to quantify the effects of CVR and by extension optimising the grid operations without violating the power quality.

  • 20.
    García Castaño, Javier
    Mälardalen University, Department of Computer Science and Electronics.
    Algorithms and Protocols Enhancing Mobility Support for Wireless Sensor Networks Based on Bluetooth and Zigbee2006Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Mobile communication systems are experiencing a huge growth. While traditional communication paradigms deal with fixed networks, mobility raises a new set of questions, techniques, and solutions. This work focuses on wireless sensor networks (WSNs) where each node is a mobile device. The main objectives of this thesis have been to develop algorithms and protocols enabling WSNs with a special interest in overcoming mobility support limitations of standards such as Bluetooth and Zigbee. The contributions of this work may be divided in four major parts related to mobility support. The first part describes the implementation of local positioning services in Bluetooth since local positioning is not supported in Bluetooth v1.1. The obtained results are used in later implemented handover algorithms in terms of deciding when to perform the handover. Moreover local positioning information may be used in further developed routing protocols. The second part deals with handover as a solution to overcome the getting out of range problem. Algorithms for handover have been implemented enabling mobility in Bluetooth infrastructure networks. The principal achievement in this part is the significant reduction of handover latency since sensor cost and quality of service are directly affected by this parameter. The third part solves the routing problems originated with handovers. The main contribution of this part is the impact of the Bluetooth scatternet formation and routing protocols, for multi-hop data transmissions, in the system quality of service. The final part is a comparison between Bluetooth and Zigbee in terms of mobility support. The main outcome of this comparison resides on the conclusions, which can be used as a technology election guide.

    The main scientific contribution relies on the implementation of a mobile WSN with Bluetooth v1.1 inside the scope of the ”Multi Monitoring Medical Chip (M3C) for Homecare Applications” European Union project (Sixth Framework Program (FP6) Reference: 508291) offering multi-hop routing support and improvements in handover latencies with aid of local positioning services.

  • 21.
    Gauffin, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering.
    Evaluation of Weak Relations in TracFeed2008Student thesis
    Abstract [en]

    This report is a master degree thesis in electronics that examines if weak relations can be used in TracFeed. TracFeed is a simulation tool designed to aid in the dimensioning of the power supply

    system for electrical railroads. The program was originally developed by Adtranz and is today further enhanced by Balfour Beatty Rail AB.

    When using weak relations there will be fewer truncations of the steps and therefore the response time will decrease. The purpose of this thesis is to study how much time that can be gained in

    different types of simulations and in which way the result is effected because of weak relations. The theoretical part explains the fundamentals concerning electrical trains and how trains are

    modelled in TracFeed. The calculation kernel used by TracFeed is called SIMPOW and it is described as well as the modelling language which is used to create the train models.

    Weak relations are tested in two simulations. The result from those simulations shows that if a displacement in simulated time of the output is acceptable and there are many trains active

    simultaneously weak relations are an interesting alternative.

  • 22.
    Ghaviha, Nima
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bohlin, Markus
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Optimal Control of a Battery Train Using Dynamic Programming2015Conference paper (Other academic)
    Abstract [en]

    Electric propulsion system in trains has the highest efficiency compared to other propulsion systems (i.e. steam and diesel). Still, electric trains are not used on all the routes, due to the high setup and maintenance cost of the catenary system. Energy storage technologies and the battery driven trains however, make it possible to have the electric trains on the non-electrified routes as well. High energy consumption of the electric trains, makes the energy management of such trains crucial to get the best use of the energy storage device. This paper suggests an algorithm for the optimal control of the catenary free operation of an electric train equipped with an onboard energy storage device. The algorithm is based on the discrete dynamic programming and Bellman’s backward approach. The objective function is to minimize the energy consumption, i.e. having the maximum battery level left at the end of the trip. The constraints are the trip time, battery capacity, local speed limits and limitations on the traction motor. Time is the independent variable and distance, velocity and battery level are the state variables. All of the four variables are discretized which results in some inaccuracy in the calculations, which is discussed in the paper. The train model and the algorithm are based on the equations of motion which makes the model adjustable for all sorts of electric trains and energy storage devices. Moreover, any type of electrical constraints such as the ones regarding the voltage output of the energy storage device or the power output can be enforced easily, due to the nature of the dynamic programming. 

  • 23.
    Ghaviha, Nima
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bohlin, Markus
    SICS - swedish institute of computer science, Sweden.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    AN ALGORITHM FOR OPTIMAL CONTROL OF AN ELECTRIC MULTIPLE UNIT2014In: Proceedings from The 55th Conference on Simulation and Modelling (SIMS 55),21-22 October, 2014. Aalborg, Denmark, Linköping: Linköping University Electronic Press, 2014Conference paper (Refereed)
    Abstract [en]

    This paper offers a solution for the optimal EMU train (Electric Multiple Unit) operation with the aim of minimizing the energy consumption. EMU is an electric train with traction motors in more than one carriage. The algorithm is based on dynamic programming and the Hamilton-Jacobi-Bellman equation. To model the train, real data has been used, which was provided by experts from Bombardier Transportation Västerås. To evaluate the model, some experiments have been done on the energy saving in exchange for the increase in the trip time. Moreover a simple accuracy factor is introduced to evaluate the accuracy of the model. The final goal is to use this approach as a base for a driver advisory system, therefore it is important to have the amount of calculations as minimum as possible. The paper also includes the studies done on the calculation time. The solution can be used for driverless trains as well as normal trains. It should be mentioned that this paper is a part of a research which is still in progress and the final model will also be used by Bombardier Transportation Västerås as an evaluation tool for the propulsions systems and trains.

  • 24.
    Ghaviha, Nima
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bohlin, Markus
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Optimal Control of an EMU Using Dynamic Programming and Tractive Effort as the Control Variable2015In: Proceedings of the 56th SIMS, Linköping University Electronic Press, Linköpings universitet, 2015, p. 377-382Conference paper (Refereed)
    Abstract [en]

    Problem of optimal train control with the aim of minimizing energy consumption is one of the old optimal control problems. During last decades different solutions have been suggested based on different optimization techniques, each including a certain number of constraints or different train configurations, one being the control on the tractive effort available from traction motor. The problem is previously solved using dynamic programming for trains with continuous tractive effort, in which velocity was assumed to be the control variable. The paper at hand presents a solution based on dynamic programming for solving the problem for trains with discrete tractive effort. In this approach, tractive effort is assumed to be the control variable. Moreover a short comparison is made between two approaches regarding accuracy and ease of application in a driver advisory system.

  • 25.
    Gunnarsson, Tommy
    Mälardalen University, Department of Computer Science and Electronics.
    MICROWAVE IMAGING OF BIOLOGICAL TISSUES: applied toward breast tumor detection2007Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Microwave imaging is an efficient diagnostic modality for non-invasively visualizing dielectric contrasts of non-metallic bodies. An increasing interest of this field has been observed during the last decades. Many application areas in biomedicine have been issued, recently the breast tumor detection application using microwave imaging.

    Many groups are working in the field at the moment for several reasons. Breast cancer is a major health problem globally for women, while it is the second most common cancer form for women causing 0.3 % of the yearly female death in Sweden. Medical imaging is considered as the most effective way of diagnostic breast tumors, where X-ray mammography is the dominating technique. However, this imaging modality still suffers from some limitations. Many women, mostly young ones, have radiographically dense breasts, which means that the breast tissues containing high rates of fibroglandular tissues. In this case the density is very similar to the breast tumor and the diagnosis is very difficult. In this case alternative modalities like Magnetic Resonance Imaging (MRI) with contrast enhancement and Ultrasound imaging are used, however those are not suitable for large scale screening program.Another limitation is the false-negative and false-positive rate using mammography, in general 5–15 % of the tumors are not detected and many cases have to go though a breast biopsy to verify a tumor diagnosis. At last the mammography using breast compression sometimes painful, and utilizing ionizing X-rays. The big potential in microwave imaging is the reported high contrast of complex permittivity between fibroglandular tissues and tumor tissues in breasts and that it is a non-ionizing method which probably will be rather inexpensive.

    The goal with this work is to develop a microwave imaging system able to reconstruct quantitative images of a female breast. In the frame of this goal this Licentiate thesis contains a brief review of the ongoing research in the field of microwave imaging of biological tissues, with the major focus on the breast tumor application. Both imaging algorithms and experimental setups are included. A feasibility study is performed to analyze what response levels could be expected, in signal properties, in a breast tumor detection application. Also, the usability of a 3D microwave propagation simulator, (QW3D), in the setup development is investigated. This is done by using a simple antenna setup with a breast phantom with different tumor positions. From those results it is clear that strong responses are obtained by a tumor presence and the diffracted responses gives strong information about inhomogeneities inside the breast. The second part of this Licentiate thesis is done in collaboration between Mälardalen University and Supélec. Using the existing planar 2.45 GHz microwave camera and the iterative non-linear Newton Kantorovich code, developed at Département de Recherches en Electromagnétisme (DRE) at Supélec, as a starting point, a new platform for both real-time qualitative imaging and quantitative images of inhomogeneous objects are investigated. The focusing is related to breast tumor detection. For the moment the tomographic performance of the planar camera is verified in simulations through a comparison with other setups. Good calibration is observed, but still experimental work concerning phantom development etc. is needed before experimental results on breast tumor detection may be obtained.

  • 26.
    Gustafsson, Thomas
    et al.
    Scania CV, Sweden.
    Skoglund, Mats
    SICS Swedish ICT, Sweden.
    Kobetski, Avenir
    SICS Swedish ICT, Sweden.
    Sundmark, Daniel
    SICS Swedish ICT, Sweden.
    Automotive System Testing by Independent Guarded Assertions2015In: 2015 IEEE 8th International Conference on Software Testing, Verification and Validation Workshops, ICSTW 2015 - Proceedings, 2015, Vol. Article number 7107474Conference paper (Refereed)
    Abstract [en]

    Testing is a key activity in industry to verify and validate products before they reach end customers. In hardwarein- the-loop system-level verification of automotive systems, testing is often performed using sequential execution of test scripts, each containing a mix of stimuli and assertions. In this paper, we propose and study an alternative approach for automated system-level testing automotive systems. In our approach, assertion-only test scripts and one (or several) stimulionly script(s), execute concurrently on the test driver. By separating the stimuli from the assertions, with each assertion independently determining when the system under test shall be verified, we seek to achieve three things: 1) tests that better represent real-world handling of the product, 2) reduced test execution time, and 3) increased defect detection. In addition to describing our proposed approach in detail, we provide experimental results from an industrial case study evaluating the approach in an automotive system test environment.

  • 27.
    Henriksson, Tommy
    Mälardalen University, School of Innovation, Design and Engineering.
    Comparison Between a 2.45 GHz Planar and Circular Scanners for Biomedical Applications2007In: International Conference on Electromagnetic Near-Field Characterization and  Imaging (ICONIC), St. Louis, MO, USA: International Conference on Electromagnetic Near-Field Characterization and Imaging (ICONIC) , 2007, , p. 6Conference paper (Other academic)
    Abstract [en]

    Microwave imaging is an efficient technique to non-invasively visualizing dielectricproperties of non-metallic bodies. One potential of the technique is the high contrast in dielectricproperties between biological tissues. In the 80’s, Supélec developed a 2.45 GHz planarmicrowave camera, in the 90’s the group developed algorithms for quantitative microwaveimaging. The purpose of this study is to investigate the capability of these existing materials, oran extended version of them, in terms of quantitative imaging of high-contrast inhomogeneousobject for application of breast cancer detection. A two-dimensional formalization is consideredto be followed up with future three-dimensional investigations.

  • 28.
    Henriksson, Tommy
    Mälardalen University, School of Innovation, Design and Engineering.
    CONTRIBUTION TO QUANTITATIVE MICROWAVE IMAGING TECHNIQUES FOR BIOMEDICAL APPLICATIONS2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This dissertation presents a contribution to quantitative microwave imaging for breast tumor detection. The study made in the frame of a joint supervision Ph.D. thesis between University Paris-SUD 11 (France) and Mälardalen University (Sweden), has been conducted through two experimental microwave imaging setups, the existing 2.45 GHz planar camera (France) and the multi-frequency flexible robotic system, (Sweden), under development. In this context a 2D scalar flexible numerical tool based on a Newton-Kantorovich (NK) scheme, has been developed.

    Quantitative microwave imaging is a three dimensional vectorial nonlinear inverse scattering problem, where the complex permittivity of an object is reconstructed from the measured scattered field, produced by the object. The NK scheme is used in order to deal with the nonlinearity and the ill-posed nature of this problem. A TM polarization and a two dimensional medium configuration have been considered in order to avoid its vectorial aspect. The solution is found iteratively by minimizing the square norm of the error with respect to the scattered field data. Consequently, the convergence of such iterative process requires, at least two conditions. First, an efficient calibration of the experimental system has to be associated to the minimization of model errors. Second, the mean square difference of the scattered field introduced by the presence of the tumor has to be large enough, according to the sensitivity of the imaging system.

    The existing planar camera associated to a flexible 2D scalar NK code, are considered as an experimental platform for quantitative breast imaging. A preliminary numerical study shows that the multi-view planar system is quite efficient for realistic breast tumor phantoms, according to its characteristics (frequency, planar geometry and water as a coupling medium), as long as realistic noisy data are considered. Furthermore, a multi-incidence planar system, more appropriate in term of antenna-array arrangement, is proposed and its concept is numerically validated.

    On the other hand, an experimental work which includes a new fluid-mixture for the realization of a narrow band cylindrical breast phantom, a deep investigation in the calibration process and model error minimization, is presented. This conducts to the first quantitative reconstruction of a realistic breast phantom by using multi-view data from the planar camera. Next, both the qualitative and quantitative reconstruction of 3D inclusions into the cylindrical breast phantom, by using data from all the retina, are shown and discussed. Finally, the extended work towards the flexible robotic system is presented.

  • 29.
    Henriksson, Tommy
    Mälardalen University, School of Innovation, Design and Engineering.
    Quantitative Imaging Using a 2.45 GHzPlanar Camera2007In: 5th World Congress on Industrial Process Tomography, Bergen, Norway, Bergen, Norway, 2007, , p. 8Conference paper (Other academic)
    Abstract [en]

    Microwave imaging is recognized as an efficient diagnostic modality for no invasively visualizingdielectric contrasts in non metallic bodies. The usefulness of this modality results from the existingcorrelation between dielectric properties and quantities of practical relevance for industrial orbiomedical applications. At the beginning of the 80’s, Supélec developed a 2.45 GHz planarmicrowave camera, in the 90’s the group developed algorithms for quantitative microwave imaging.The purpose of this study is to investigate the capability of these existing materials, or an extendedversion of it, in terms of quantitative imaging of high contrast inhomogeneous object for application ofbreast cancer detection.

  • 30.
    Henriksson, Tommy
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Joachimowicz, Nadine
    L2S/Supélec/Université Paris-SYD 11.
    Conessa, Christophe
    L2S/Supélec/Université Paris-SYD 11.
    Bolomey, Jean-Charles
    L2S/Supélec/Université Paris-SYD 11.
    Quantitative Microwave Imaging for Breast Cancer Detection Using a Planar 2.45 GHz System2010In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 59, no 10, p. 2691-2699Article in journal (Other academic)
    Abstract [en]

    Microwave imaging is recognized as a potentialcandidate for biomedical applications, such as breast tumordetection. In this context a planar microwave camera isinvestigated for quantitative imaging of inhomogeneous objects.Promising simulation results indicates that the planar geometryis suitable for quantitative imaging, as long as the signal to noiseratio is higher than 40 dB. Different calibration techniques arediscussed with several proposed model improvements and thefirst reconstructed quantitative image of an inhomogeneous 2Dobject is obtained by using experimental data from the camera.

  • 31.
    Henriksson, Tommy
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Joachimowicz, Nadine
    L2S/Supélec/Université Paris-SUD 11.
    Duchêne, Bernard
    L2S/Supélec/Université Paris-SUD 11.
    Bolomey, Jean-Charles
    L2S/Supélec/Université Paris-SUD 11.
    Breast Tumor Detection Ability Using aPlanar 2.45 GHz SystemManuscript (Other academic)
    Abstract [en]

    This paper deals with the breast tumor detectionability of a planar microwave imaging system. Indeed, microwaveimaging seems to have a significant potential in such a biomedicalapplication. By means of a numerical model based upon electricfield volume integral equations, we investigate the influence ofseveral parameters, such as the respective sizes of the breastand the tumor, the operating frequency and the electromagneticproperties of the different media, on the detection ability. Thelatter is estimated by comparing the scattered fields observed inthe presence and in the absence of tumor and by accounting forthe signal to noise ratio available with the experimental setupdeveloped at the laboratory.

  • 32.
    Henriksson, Tommy
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Joachimowicz, Nadine
    L2S/Supélec/Université Paris-SYD 11.
    Joisel, Alain
    L2S/Supélec/Université Paris-SYD 11.
    Conessa, Christophe
    L2S/Supélec/Université Paris-SYD 11.
    Diet, Antoine
    L2S/Supélec/Université Paris-SYD 11.
    Bolomey, Jean-Charles
    L2S/Supélec/Université Paris-SYD 11.
    Quantitative Microwave Breast Phantom Imaging Using a Planar 2.45 GHz System2008In: (Supélec), XXIX General Assembly of URSI, International Union of Radio Science, Chicago, MO, USA, August, 2008, Chicago, Illinois, USA: XXIX General Assembly of the International Union of Radio Science, URSI , 2008, , p. 4Conference paper (Other academic)
    Abstract [en]

    Breast cancer is a global health problem, needing cheep and effective alternative diagnosis methods in order to minimize the mortality. This experimental study is performed in the context of an ongoing collaborative project towards a future planar three-dimensional microwave breast mammography system. Herein the first quantitative image of an inhomogeneous breast tumor phantom, composed by different Triton X-100/water/salt mixtures, is obtained by using the existing planar 2.45 GHz microwave camera.

  • 33.
    Hilmersson, Anette
    Mälardalen University, School of Innovation, Design and Engineering.
    Multisensor Stress Monitoring For Non-Stationary Subjects2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Monitoring stress in real-time, in a non-laboratory environment can be benecial in several applications. One of these, which have been the motivation for this thesis, is to to perform this measurement during Attention decit hyperactivity disorder (ADHD) diagnosis. Monitoring several physiological responses to internal or external stimuli in a single soft-real-time system is nota solution widely used in an application like this. The thesis starts by studying several stress related responses in detail. Sensors for all of the responses are not implemented nor is it possible toimplement in to the desired system. After the study is was decided to implement two measurement modules. The first a Photo-plethysmogrophy (PPG) measurement module to measure heart rate and also estimate breathing. This module is prepared for estimating arterial blood oxygen levels but the calculation or verification have not been done. The second is Skin Conductance (SC) measurement module and in to both ofthese add a temperature sensor to measure the temperature of the skin. Time constraints limit the SC module to only be presented in theory. The PPG module on the other hand have been realisedin a prototype. This prototype performs the measurement in transmissive mode on the left earlobe, which leaves the hands free and it does not affect the hearing on that ear. The prototype giveout acceptable signal quality when good contact with the measurement site is achieved. The signalinterpretation, such as performing the signal analysis to count the beats per minute, is outside thescope of this thesis and will therefore not be presented but the signals can be seen in figures.

  • 34.
    Holmberg, Johnny
    Mälardalen University, Department of Electronics.
    On Design, Analysis, and Implementation of LDI/LDD Lattice Filters2002Doctoral thesis, monograph (Other scientific)
  • 35.
    Isaksson, Mathias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Knapik, Lukas
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of a Multi‐bus platform for automation testbed2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The task for this thesis was to develop, construct and evaluate a multi‐bus communication system,connected to a PC via USB and capable of communicating in CAN, I2C and SPI and develop drivers for itin National Instruments LabVIEW.In the beginning a study was made of the communication buses followed by an investigation of whattype of hardware that could accomplish this task. A microcontroller unit was selected andprogrammed in MikroElektronika MikroC Pro v.3.2 to act as the interface between the communicationbusses and PC. A PCB prototype of the system was constructed by using Eagle Cad software v.5.6.0. General drivers for this system where created in LabVIEW v.8.6.1 so the end‐user simply can createtheir own applications and control the compatible hardware depending on their type of purposes. Thesystem was tested on criteria’s such as: speed, power consumption, burst performance andtransmission length depending on which communication bus was used.

  • 36.
    Jankoski, Radoslav
    et al.
    Ss. Cyril and Methodius University, FEIT, Skopje, Macedonia .
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Arnautovski-Toseva, Vesna
    Ss. Cyril and Methodius University, FEIT, Skopje, Macedonia .
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Comparison of TL, Point-Matching and Hybrid Circuit Method Analysis of a Horizontal Dipole Antenna Immersed in Lossy Soil2016In: Engineering Mathematics I: Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering / [ed] Sergei Silvestrov, Milica Rančić, Heidelberg: Springer, 2016, p. 51-63Chapter in book (Refereed)
    Abstract [en]

    HF analysis of a horizontal dipole antenna buried in lossy ground has been performed in this paper. The soil is treated as a homogenous half-space of known electrical parameters. The authors compare the range of applicability of two forms of transmission line model , a hybrid circuit method, and a point-matching method in such analysis.

  • 37.
    Jansson, Hampus
    Mälardalen University, School of Business, Society and Engineering.
    SOLENERGI FÖR JORDBRUKSNÄRINGAR: Ekonomiska förutsättningar för jordbruksnäringar för installation av solcellsanläggningar2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this project is to analyze the economic parameters that affects the profits from a roof mounted solar cell installation for an agriculture company in Sweden. To analyze the different production type and the impact of the fraction self- used electricity is calculated with respect to the direction of the installation. The parameters that are affecting the profit are the yearly electricity production, the investment cost, the fraction self-used, the price of bought and sold electricity and any subsidies. The conclusion is that the type of production does not affect the self use as much and an installation facing south still have a higher self use due to the higher total electricity production. The most important factor for profit is the subsides, without subsidies the investment does not give a positive yield rate. In second place comes the orientation and the total investment cost. Two of the three companies studied would get 1-3% inflation compensated interest rate with 20% subsidies and the third, relatively located far up north, reached 1-2% inflation compensated interest rate with the same subsides. The lower interest rate comes from the lower yearly electricity production. Another 2 percentage interest rate can be added if the subsides of 40% is granted for all three of the studied companies. As complement to the already existent feeder cable a solar plant combined with a battery storage can support a new house on the property during summer. As a backup for a power outage, a solar plant and a battery costs more and does less than a tractor driven electric generator.

  • 38.
    Jansson, Magnus
    Mälardalen University, Department of Computer Science and Electronics.
    On Stabilization of Sensorless Synchronous Motor Drives and Traction Converters2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In this thesis we discuss and analyze aspects and methods for low-speed poeration, startup, and particularly rotational reversal for sensorless control of non-salient permanent-magnet synchronous motors (PMSMs), i.e., stabilization in the low-speed region. Furtermore, a speed and position estimation algorithm for speed-sensorless control of electrically excited synchronous machines (EESMs) with damper windings is developed. For EESM drives, an initial rotor position estimation algorithm is also developed. Regarding the PMSM drives, it is shown that the sensorless drive synchronizes from any initial rotor position, recovers from initial rotation in the wrong direction, and also reverses rotation without lockup or instability phenomena.

    The result regarding sensorless control and preformance in the low-speed region are simulated and experimentally verified, which indicates that the proposed estimator is effective. An additional subject in this thesis is control traction converters. One major problem is that trains with pulse-width-modulation (PWM) converters have active input impedance; thus the phase shift between the input current and voltage is greater than +90 degrees or less than -90 degrees for a certain ferquency region. This may result in poor damping and in worst case unstable operation. Here, it is shown that via sophisticated current control and improved feed-forward, one may stabilize the system with respect to passivity.

  • 39.
    Javor, Vesna
    et al.
    University of Nis, Faculty of Electronic Eng., Serbia.
    Lundengård, Karl
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Electrostatic discharge currents and their derivatives' approximation by piecewise power-exponential functions2018In: Turkish Journal of Electrical Engineering and Computer Sciences, ISSN 1300-0632, E-ISSN 1303-6203, Vol. 26, no 2, p. 1093-1102Article in journal (Refereed)
    Abstract [en]

    An analytically extended function based on power-exponential functions is used in this paper for approxi- mation of electrostatic discharge (ESD) currents and their derivatives. The Marquardt least-squares method (MLSM) is applied for obtaining nonlinear function parameters. IEC 61000-4-2 Standard ESD current is approximated, as well as some measured ESD currents' wave shapes. Power-exponential terms are extended at the local maxima and minima of the represented wave shape, so that this approximation is done from peak to peak. ESD current derivative is approxi- mated using the same procedure in order to obtain the continuous second order derivative of the current, as all piecewise functions are of differentiability class C1L . Currents and their derivatives are often measured in ESD experiments so that their analytical representation is needed for simulation of ESD phenomena, better definition of standard requirements, and computation of the transient fields and induced effects.

  • 40.
    Johansson, Joakim
    Mälardalen University, School of Business, Society and Engineering.
    Optimization of Section Points Locations in Electric Power Distribution Systems: Development of a Method for Improving the Reliability2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The power distribution system is the final link to transfer the electrical energy to the individual customers. It is distributed in a complex technical grid but is associated with the majority of all outages occurring. Improving its reliability is an efficient way to reduce the effects of outages.

    A common way of improving the reliability is by designing loop structures containing two connected feeders separated by a section point. The location of the section point will decide how the system structure is connected and its level of reliability. By finding the optimal location, an improved reliability may be accomplished.

    This Master’s thesis has developed a method of finding optimized section points locations in a primary distribution system in order to improve its reliability. A case study has been conducted in a part of Mälarenergi Elnät’s distribution system with the objective of developing an algorithm in MATLAB able to generate the optimal section points in the area. An analytical technique together with a method called Failure Modes and Effect Analysis (FMEA) as preparatory step, was used to simulate the impact of outages in various components based on historical data and literature reviews. Quantifying the impact was made by calculating the System Average Interruption Duration Index (SAIDI) and the Expected Cost (ECOST) which represented the reliability from a customer- and a socio-economic perspective.

    Using an optimization routine based on a Greedy algorithm an improvement of the reliability was made possible. The result of the case study showed a possible improvement of 28% on SAIDI and 41% on ECOST if optimizing the location of section points. It also indicated that loop structures containing mostly industry-, trade- and service-sectors may improve ECOST considerably by having a relocated section point.

    The analysis concluded that based on the considerable improvement the case study showed, a distribution system could be highly benefitted by optimizing the location of section points. The created algorithm may provide a helpful tool well representative for such a process in a cost-effective way. Applying it into a full size system was considered being possible but it would first require some additional improvements of reliability inputs and to resolve some fundamental issues like rated current in lines and geographical distances to substations. 

  • 41.
    Jonsson, Annika
    Mälardalen University, Department of Computer Science and Electronics.
    Pressure sore etiology - highlighted with optical measurements of the blood flow2006Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In line with the quality awareness of good prevention of pressure sores and in treatment of those sores already developed, evaluation of antidecubitus mattresses plays an important role. However, there are shortages in the evaluations performed today, since often interface pressure is the only parameter regarded. Since ischaemia in the tissue is the primary cause of pressure sore, the focus in this thesis is on blood flow measurements in tissue exposed external loading. To study the tissue blood flow would give a better and more direct indication on the mattress effectiveness in minimizing the negative effects on the tissue viability.

    The results presented in this thesis reveal that the superficial blood flow in areas prone to pressure sore development, is affected by increased skin temperature and external loading of the tissue. Both the effects from pressure and shear stress have been studied.

    Measurements of the tissue blood flow is interesting to relate to the two theories about at which tissue layer the pressure sores start to develop. To achieved more knowledge about the pressure sore etiology and also be able to non-invasively measure the tissue blood flow for evaluations of antidecubitus mattresses an optical sensor has been developed. The sensor combines the two optical methods, laser Doppler flowmetry and photoplethysmography. With the design of the sensor, measurements of the superficial skin blood flow and the deeper blood flow, even the muscle blood flow, can be performed. Measurement depths of 2 mm, 8 mm, and 20 mm into the tissue is assumed.

    Preliminary result from measurements performed with the optical sensor in four test subjects, revealed great individual differences in blood flow, but also different response to the same external loading at different measurement depths, in the same individual. This new optical sensor is likely to be of great value in future studies of pressure sore etiology and in future evaluations of antidecubitus mattresses.

  • 42.
    Kantsaporidis, Ioannis
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Al-Attar, Sadeq
    Mälardalen University, School of Innovation, Design and Engineering.
    Dynamics and electronics of a manually chargeable quadcopter for steady-state flight2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this thesis is to investigate how the onboard battery of a quadcopter can be charged through manual rotation of its motors, while understanding the resulting aerodynamical forces acting on the rotors during hover, as well as considering the changes in thrust capabilities when the electronic and structural design are altered. A theoretical approach using the momentum theory will present a general understanding of rotor performance whilst describing the correlation between rotor parameters, thrust and mechanical power. Furthermore, the idea of using the motors as generators are put under study to investigate their electrical output and utilize them to recharge the battery. This is done using the counter electromotive force equation, and a sequence of other equations that will present numerical data of actual manual work converted into electrical power. Resulting in the required time to manually recharge the quadcopter subsequently sustaining hover flight for three minutes. It is concluded in this report that manual recharging of the battery using the motors as generators is possible, as well as maintaining its flying ability in case of added weight. Although not deemed practical in commercial use, it is a new methodology with the intention to develop a sustainable quadcopter further expanding its practical applications in both aviation industry and human aid.

  • 43.
    Karlsson, Christer
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering.
    Dahlquist, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    New Methods for Adaptation to Degeneration in Process Models for Process Industries2009In: Chemical Product and Process Modeling, Vol. Vol. 4, no : Iss. 1, p. , Article 25.-Article in journal (Refereed)
    Abstract [en]

    The implementation of model-based control and diagnostics suffer strongly from the fact that models deteriorate as a function of process and sensor deterioration. Also, changes in the raw material (i.e. wood) may occur and often the process control is not addressing these variations in reality. It is thus vital for the model system to be robust in the sense that it is transparent and easy for the operator to maintain. Robustness is essential in many parts of the system, including measurement, process model validation, the ability of the model to adapt to changes in the process, optimization algorithms, and of course the model itself. In this paper, we first show three real-life applications of the utilization of models for diagnostics and control. Thereafter conditions for on-line adaptation of the models are discussed. The challenges when designing such a system are in achieving operator confidence, filtering of misleading measured data, adaptation of process parameters when the process parameters change, and combining validation of measurements and process models. These challenges are met by using a combination of physical and statistical models and methods based on them such as model predictive control (MPC) and parameter estimation. The model should be maintained by a qualified engineer who should be able to explain the system to the operator so that it is understood and confidence can be maintained.

  • 44.
    Karp, Jonas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Ek, Robert
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of a Handheld Night Vision System2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The task for this master thesis was to create a specification for a second prototype of Scandilumen´s handheld gated night vision system. Current prototype is analogue and is to be upgraded with a digital interface. The specification was to contain information about manufacturers and performance on critical components such as image intensifier tube, image sensor and display. Scandilumen have previous experience with CCD cameras and wanted to know if the CMOS technology were sensitive enough to work properly in gated systems where high sensitivity is critical. Different image processing techniques was analyzed to find out the possibility to enhance image quality with an FPGA built-in into the system. When the specification is implemented, Scandilumen will have a prototype up-to-date with a digital interface and real time image enhancement.

  • 45.
    Khamespanah, Ehsan
    et al.
    Univ Tehran, Sch ECE, Tehran, Iran.;Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.;Reykjavik Univ, CRESS, Reykjavik, Iceland..
    Sirjani, Marjan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.
    Mechitov, Kirill
    Univ Illinois, OSL, Champaign, IL USA..
    Agha, Gul
    Univ Illinois, OSL, Champaign, IL USA..
    Modeling and analyzing real-time wireless sensor and actuator networks using actors and model checking2018In: International Journal on Software Tools for Technology Transfer (STTT), ISSN 1433-2779, E-ISSN 1433-2787, Vol. 20, no 5, p. 547-561Article in journal (Refereed)
    Abstract [en]

    Programmers often use informal worst-case analysis and debugging to ensure that schedulers satisfy real-time requirements. Not only can this process be tedious and error-prone, it is inherently conservative and thus likely to lead to an inefficient use of resources. We propose to use model checking to find a schedule which optimizes the use of resources while satisfying real-time requirements. Specifically, we represent a Wireless sensor and actuator network (WSAN) as a collection of actors whose behaviors are specified using a Java-based actor language extended with operators for real-time scheduling and delay representation. We show how the abstraction mechanism and the compositionality of actors in the actor model may be used to incrementally build a model of a WSAN's behavior from node-level and network models. We demonstrate the approach with a case study of a distributed real-time data acquisition system for high-frequency sensing using Timed Rebeca modeling language and the Afra model checking tool.

  • 46.
    Kivinen, Jonne
    Mälardalen University, School of Innovation, Design and Engineering.
    Demonstrator av vinkelgivare2009Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Eskilstuna Elektronikpartner (EEPAB) is an electronics company located in Eskilstuna that produces angle sensors to, for instance, cranes mounted on truck beds.

    For EEPAB to be able to demonstrate their product on fairs in an interesting way, a demonstrator has been made. The demonstrator consists of a remote controlled excavator and an electronic unit which handles the analog signal from the sensor. The result, which is the angle of the sensor in degrees, is presented on two sevensegment displays that are placed on both sides of the excavator. The angle is also sent wirelessly from the electronic unit via Bluetooth to a PC. The battery of the excavator powers all of the hardware, making the demonstrator fully portable.

    This thesis report describes the various programfunctions and hardware, part by part, necessary for a complete and functioning demonstrator.

  • 47.
    Kus, Emre
    Mälardalen University, School of Innovation, Design and Engineering.
    Myoelectric Interface2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The intention of this thesis project report is to control a servo motor by using Electromyography(EMG) signals in the purpose of learning about bioamplifers and how ATMEL AVR Series microcontrollers work.

    EMG is the a test that is used to record the electrical activity of muscles. In order to fulfill our intention an EMG amplifier, an ADC converter and a servo motor controller is build to be used with the simple mechenical gripper where the control of the gripper is directly related with the amplitude of the EMG signals taken from the hand muscles. In the development and USART serial communication part is also added enabling to see the ADC results in computer.

  • 48.
    Landernäs, Krister
    Mälardalen University, Department of Computer Science and Electronics.
    Implementation of digital-serial LDI/LDD allpass filters2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In this thesis, digit-serial implementation of recursive digital filters is considered. The theories presented can be applied to any recursive digital filter, and in this thesis we study the lossless discrete integrator (LDI) allpass filter. A brief introduction regarding suppression of limit cycles at finite wordlength conditions is given, and an extended stability region, where the second-order LDI allpass filter is free from quantization limit cycles, is presented.

    The realization of digit-serial processing elements, i.e., digit-serial adders and multipliers, is studied. A new digit-serial hybrid adder (DSHA) is presented. The adder can be pipelined to the bit level with a short arithmetic critical path, which makes it well suited when implementing high-throughput recursive digital filters.

    Two digit-serial multipliers which can be pipelined to the bit level are considered. It is concluded that a digit-serial/parallelmultiplier based on shift-accumulation(DSAAM) is a good candidate when implementing recursive digital systems, mainly due to low latency. Furthermore, our study shows that low latency will lead to higher throughput and lower power consumption.

    Scheduling of recursive digit-serial algorithms is studied. It is concluded that implementation issues such as latency and arithmetic critical path are usually required before scheduling considerations can be made. Cyclic scheduling using digit-serial arithmetics is also considered. It is shown that digit-serial cyclic scheduling is very attractive for high-throughput implementations.

  • 49.
    Lundengård, Karl
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Application of the Marquardt Least Square Method to the Estimation of Pulse Function Parameters2014In: 10TH INTERNATIONAL CONFERENCE ON MATHEMATICAL PROBLEMS IN ENGINEERING, AEROSPACE AND SCIENCES: ICNPAA 2014Conference date: 15–18 July 2014 Location: Narvik, Norway ISBN: 978-0-7354-1276-7 Editor: Seenith Sivasundaram Volume number: 1637 Published: 10 december 2014, 2014, p. 637-646Conference paper (Refereed)
    Abstract [en]

    Application of the Marquardt least-squares method (MLSM) to the estimation of non-linear parameters of functionsused for representing various lightning current waveshapes is presented in this paper. Parameters are determined for the Pulse,Heidler’s and DEXP function representing the first positive, first and subsequent negative stroke currents as given in IEC62305-1 Standard Ed.2, and also for some other fast- and slow-decaying lightning current waveshapes. The results prove theability of the MLSM to be used for the estimation of parameters of the functions important in lightning discharge modeling.

  • 50.
    Lundengård, Karl
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Electrostatic Discharge Currents Representation using the Multi-Peaked Analytically Extended Function by Interpolation on a D-Optimal Design2017Conference paper (Refereed)
    Abstract [en]

    Multi-peaked analytically extended function (AEF), previously applied by the authors to modelling of lightning discharge currents, is used in this paper for representation of the electrostatic discharge (ESD) currents. The fitting to data is achieved by interpolation of certain data points. In order to minimize unstable behaviour, the exponents of the AEF are chosen from a certain arithmetic sequence and the interpolated points are chosen according to a D-optimal design. ESD currents’ modelling is illustrated through two examples: one corresponding to an approximation of the IEC Standard 61000-4-2 waveshape, and the other to representation of some measured ESD current. 

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