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  • 301.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Tore
    Wickramanayake, Anura
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Project: Improved measurements of mining induced ground deformations using GPS and SAR techniques2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The LKAB SAR project is implemented to measure the subsidence and terrain deformation around the Kiruna iron ore mine and in the Kiruna city area. The LKAB SAR project has two components. One is the monitoring component in which MDA (main contractor) provides the SAR deformation maps to LKAB and the second is the technology transfer component in where MDA provides theoretical and practical knowledge to LKAB so that LKAB can produce deformation maps by their own. And Cranfield University and Luleå University of technology will carryout the LKAB SAR research. During the SAR project it is expected to use “DInSAR” and “CTM” techniques to measure the deformations. By using DInSAR and CTM techniques, LKAB can achieve the required accuracy levels during the summer season but it is likely that the quality and quantity of the measurements will largely differ during winter season (due to the thick snow cover). Similarly, areas which have thick forest cover will prevent radar waves reaching the ground and because of that it is likely the quality and quantity of the measurements will decrease in such areas during the mid summer period. Therefore LKAB is planning to carry out a research program to improve the SAR measurements.

  • 302.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lundgren, Urban
    Luleå University of Technology.
    Nemeth, Robert
    Luleå University of Technology.
    Electromagnetic shielding capabilities of conductive thermoplastic materials and three measurement methods for evaluation2002Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report summarizes the work to compare 12 conductive thermoplastics using three measurement methods. The 12 thermoplastic materials were chosen to observe the influence of variation of base polymer, variation of additives, different mechanical properties and processing and mouldability properties. Test samples were manufactured to be useful in fixtures for far field insertion loss measurements, and to load a coaxial transmission line. Boxes were made to make an enclosure for an electric field source, this arrangement was used for simple application-like near field insertion loss measurements. With all three methods data was obtained in the frequency range from 100 MHz to 1000 MHz for- far field shielding effectiveness- near field shielding effectiveness- complex permeability- complex permittivityResults were obtained showing that variations in the manufacturing process where extra heated thermoplastics or yeast additive was tested, did not improve the shielding efficiency for the particular compounds that was used. The mesurements indicates that a higher amount of additive improves both the near field SE and the far field SE. Measured far field SE is in good agreement with the numerical simulations based on the measured material data.

  • 303.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Monsefi, F.
    Optimization of PEEC based electromagnetic modeling code using grid computing2006Ingår i: EMC Europe 2006 Barcelona: [International Symposium on Electromagnetic Compatibility ; September 4 - 8, 2006, Barcelona, Spain] / [ed] Ferran Silva, Barcelona: Universidad Politécnica de Cataluña , 2006Konferensbidrag (Refereegranskat)
  • 304.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Niska, Stefan
    PEEC based formulation suitable for electromagnetic analysis of railway structures2004Ingår i: EMC Europe 2004: International Symposium on Electromagnetic Compatibility; September 6 - 10, 2004, Technische Universiteit, Eindhoven, the Netherlands / [ed] A. P. J. van Deursen, Eindhoven: Technische Universiteit Eindhoven, 2004Konferensbidrag (Refereegranskat)
  • 305.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Safavi, Sohrab
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Project: Full-wave electromagnetic modeling with active circuit elements2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Syftet med doktorandprojektet är att utveckla en programvara som kan lösa kretsekvationer för passiva och aktiva komponenter samtidigt som elektromagnetiska problem beskrivna mha ekvivalenta kretsar (Eng. PEEC) löses. Projektet bygger vidare på programvara som tagits fram på EISLAB under de senaste 10 åren och som nu används i flertalet projekt med regionala, nationella och internationella parter. I feb. 2011 har doktoranden en första implementation av en fungerande PEEC-lösare som stödjer aktiva komponenter i form av transistorer (BJTs) och dioder. Nästa steg är att utöka stödet för olika transistormodeller, förna implementationen och inkorporera den i den existerande MultiPEEC-programvaran som utvecklas i ett parallellt projekt.

  • 306.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wisten, Åke
    Experimental investigation of the current distribution in the couplings of moving trains2009Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, nr 1, s. 311-318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transport of iron ore from the Swedish mining areas to the harbors is carried out by electric trains. In 2003, there was a dramatic increase in the number of bearings discarded due to electric current corrosion. No evident reason to this increase could be found and a project was initiated measuring electrical currents in engines and couplings as well as position and velocity of the train in an attempt to find countermeasures to the excess currents in the bearings. The RMS-magnitudes of the currents have been recorded and compared for different positions on the train, for different train configurations, and at different driving conditions. The results showed substantial electrical currents going through the couplings and much higher currents in modern trains with 30 tons axle load compared to old trains with 25 tons axle load.

  • 307.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wisten, Åke
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Project: Electromagnetic compatibility issues in the Swedish railway system2011Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 308.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Intelligent industrial Processes: Big data devices2014Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A versatile and competitive process industry is important for both Sweden's and Europe's future status as new players are emerging. To secure our position, constant improvement and development of industrial processes are required in order to increase productivity while reducing the pressures on the climate and the environment. One key area is ProcessIT (or Process industrial automation) in which several Swedish companies are world leaders in its development, delivery and application.The interest for new technologies such as Internet of Things (IoT), Cyber-Physical Systems (CPS), Big data, and Cloud computing have been increasing rapidly the last years. There have been a number of predictions from some of the world's largest companies in the business of computer communication, such as Cisco, Intel, Ericsson, etc. where the number of Internet connected devices will reach somewhere between 30 and 50 billion devices by the year 2030. This will include traditional devices such as computers and laptops, tablets, smart phones as well as new types of devices such as resource-constrained sensor and actuator platforms.

  • 309.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Low-power design methodologies for embedded internet systems2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Embedded systems are resource-constrained special-purpose computers, capable of both sensing and controlling the environment they are placed in. An embedded system usually consists of both hardware and software. The hardware can be composed of sensors, actuators, processors, memory storage devices, communication peripherals, and power supplies. The software typically includes an operating system, device drivers, and an application-specific algorithm for controlling the system's behavior. A special class of embedded systems is comprised by systems that can communicate using standard Internet protocols. Such systems, called Embedded Internet Systems (EIS), are capable of transmitting sensor data directly to the Internet without using specialized gateways. Sensor nodes (nodes in a sensor network) are an example of specialized embedded systems. Sensor nodes with wireless communication capabilities can form a wireless network of sensors. Two types of such networks are usually distinguished - Wireless Sensor Networks (WSN) and Personal Area Networks (PAN). Wireless sensor networks may consist of hundreds or even thousands of sensor nodes; they can be used in industrial applications and deployed in hazardous environments, such as battlefields, volcanos, and forest fires. Personal area networks, on the other hand, are normally composed of a relatively small number of devices, which minimizes requirement on scalability. PAN devices use general-purpose technologies and standard protocols, such as Wi-Fi and Bluetooth, and they are designed for applications such as video and audio streaming, web browsing, and file transfer. Today's research on WSN technology is focused on creating power-efficient large-scale networks using highly specialized protocols and technologies; they are usually intended for scientific, military, and industrial usage scenarios. Research on PAN technology targets consumer needs, where two important requirements are interoperability, through the use of general-purpose technologies and protocols, and usability, often achieved by supporting dynamic address allocation and well-known service discovery protocols. When sensor nodes are used in personal area networks, they should have both features normally characteristic of WSN nodes and those more typical of PAN nodes. A sensor network based on general-purpose technologies should be power-efficient while at the same time enabling interoperability with consumer devices. By using consumer devices, such as mobile phones, and widely available access networks, such as GPRS and UMTS cellular networks, such sensor nodes can achieve worldwide mobility. This is in contrast to traditional wireless sensor networks where the focus is on achieving efficient communication within the network using highly specialized protocols and technologies. This thesis investigates the feasibility of using Embedded Internet Systems as wirelessly networked sensor nodes using standard protocols and commercial off-the-shelf (COTS) components. The focus is on reducing sensor nodes' power consumption while still allowing interoperability with standard consumer devices, such as mobile phones, PDAs, and computers. In other words, the goal is to merge WSN and PAN technologies to produce a new type of wirelessly networked sensor nodes with an operational lifetime in the range of months to years, which communicate using well-known protocols, such as Bluetooth and TCP/IP. Bluetooth was chosen since it is by far the most wide-spread protocol supported by existing consumer devices, and we call the resulting sensor networks Bluetooth Sensor Networks (BSN). BSN nodes are EIS devices used in the context of sensor networks, and the main motivation for this type of sensor networks is to allow sensors, such as GPS, pulse oximeters, and thermometers, to be used in conjunction with standard consumer devices and applications. The work presented in this thesis has resulted in a system architecture which supports sensor networks consisting of EIS devices with a lifetime of several years, energy scavenging capabilities, and user-oriented low-power operation. The use of TCP/IP and Bluetooth enables interoperability with existing infrastructures, such as the Internet, and mobility, when Bluetooth-enabled mobile phones are used as gateways to cellular networks. It has also be demonstrated that it is feasible to utilize Bluetooth and TCP/IP on resource-constrained networked sensor nodes, while still enabling system operational lifetimes in the range of months to years and using a total system volume of less than 10 cm3 .

  • 310.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Almqvist, Andreas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Projekt: Y-programmet2011Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 311.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Towards road surface monitoring: experiments and technical challenges2009Ingår i: 2009 IEEE control applications (CCA) & intelligent control (ISIC): St. Petersburg, Russia, 8 - 10 July 2009 ; [18th IEEE International Conference on Control Applications (CCA) and 24th IEEE International Symposium on Intelligent Control (ISIC) ; part of the 3rd IEEE Multi-Conference on Systems and Control (MSC 2009)], Piscataway, NJ: IEEE Communications Society, 2009, s. 655-659Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper discusses results from real-life tests with intelligent road marking units (RMU), placed on the surface of a highway in northern Sweden, to monitor passing vehicles and road properties, as well as making the information available through a wireless sensor network. Wireless sensor networks are starting to gain interest in the area of cooperative safety and efficiency in transport as they can contribute to the reduction of accidents and emissions as well as enhanced driver experiences. Intelligent road markings are another key element for the creation of intelligent transport systems, complementing road side units, devices placed near a road equipped with high-performance computational platforms and long range communication capabilities. This paper shows that RMUs are feasible from the perspectives of low-power consumption, durability, and sensing performance.

  • 312.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Project: I2Mine2013Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 313.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Derhamy, Hasan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Salčič, Zoran A.
    Department of Electrical and Computer Engineering, University of Auckland.
    Wang, Kevin
    Department of Electrical and Computer Engineering, University of Auckland.
    Towards Industrial Internet of Things: An Efficient and Interoperable Communication Framework2015Ingår i: 2015 IEEE International Conference on Industrial Technology, ICIT 2015: Seville, Spain, 17-19 Mars 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 2198-2204Konferensbidrag (Refereegranskat)
    Abstract [en]

    Interoperability between shop floor devices and upper layer systems is a key challenge for enabling Internet of Things in industrial applications. Standardized protocols such as IPv6, CoAP, and XML can be used to address this issue. Widely used XML-based technologies such as SenML, EEML, OPC-UA as well as others rely on XML to be able to support a wide range of sensor and actuator applications. However, this approach results in high communication overhead due to the verbose nature of plain text messages encoded in XML. When devices are communicating using 6LoWPAN over IEEE 802.15.4, it is important to keep the messages small enough to fit into one MAC-layer frame to avoid fragmentation and hence conserving bandwidth and transmission energy. One possible solution is to integrate differential binary delta-encoding with a service-based framework based on CoAP, SenML and EXI. The proposed efficient communication approach for service-based architecture can compress a series of events up to 90-95%. The proposed framework is a holistic approach for enabling distributed monitoring and control applications and a move towards realizing the vision of Services of Things.

  • 314.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Kyusakov, Rumen
    Project: Architecture for Service-Oriented Process – Monitoring and Control2011Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 315.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Raayatinezhad, Asma
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kyusakov, Rumen
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A SOA-based framework for integration of intelligent rock bolts with internet of things2013Ingår i: Proceedings of the IEEE International Conference on Industrial Technology: ICIT 2013, Cape Town, South Africa 25 February 2013 - 28 February 2013, Piscataway, NJ: IEEE Communications Society, 2013, s. 1962-1967Konferensbidrag (Refereegranskat)
    Abstract [en]

    The mining industry is seeing a bright future with a high demand for minerals and relatively high material prices. Much of this is driven by the rapid industrial expansion in countries such as China and others. However, even though the mining business seems promising, there are some important issues that must be addressed in order to maintain a cost-effective and competitive edge. Worker and environment safety, working conditions, are very important issues. Another issue is attracting skilled personal to work in the deep mines of the future.Today, the mining industry has problems hiring personnel, due to hazardous working environments and re-locating to the distant regions. If the workers’ safety could be increased, attracting skilled personnel would become one less problem. Rock bolts and shot-crete are in use today to reinforce tunnel walls, and expensive measurement devices are used in order to monitor seismic activity and rock stress. However, by not having real-time monitoring of rock bolts makes it difficult to monitor them. A better approach would be to make rock bolts intelligent and have them measure stress and seismic activity. Furthermore, by connecting the rock bolts to a network, real-time monitoring of them is made feasible. In this paper, we propose the merger of the Internet of Things (IoT) approach with traditional rock bolts, thereby allowing online monitoring of rock bolt status. This enables an increased possibility to enhance work safety by being able to detect anomalies on the rock earlier, thereby giving workers and machinery an earlier alarm to evacuate hazardous locations in the mine.

  • 316.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Thompson, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Cheng, Yi-Bing
    Monash University, Melbourne, VIC.
    Chen, Peter
    National Cheng Kung University.
    Low-cost PCB integration of dye-sensitised solar cells for WSAN applications2012Ingår i: International Journal On Advances in Systems and Measurements, ISSN 1942-261x, Vol. 5, nr 1-2, s. 45-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Internet of Things is envisioned to drastically chance the way sensor data from physical phenomena can be utilized by users on the Internet. However, one concern in deploying and maintaining a large number of sensor nodes is that replacing spent batteries will not be feasible. One solution to this issue may involve utilising energy harvesting technologies, e.g. solar, heat, or vibration, withsolar being the most promising for general applications. However, using solar panels is currently a relatively expensive approach as they require a time-consuming and therefore costly assembly process. As an alternative, this paper suggests a new approach to powering networked sensors: the direct integration of a solar cell onto a sensor nodes printed circuit board. This approach eliminates the need for manual assembly and the use of expensive connectors.

  • 317.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Thompson, Simon J.
    Monash University, Melbourne, VIC.
    Cheng, Yi-Bing
    Monash University, Melbourne, VIC.
    PCB Integration of dye-sensitised solar cells for low-cost networked embedded systems2011Ingår i: SENSORCOMM, 2011, s. 215-222Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wireless sensor networks are envisioned to make a large impact on how sensor data from physical phenomena can be utilized by millions of users on the Internet. However, one concern in deploying a large number of real-world physical sensors is that replacing spent batteries might not be feasible. One solution to this issue may involve energy harvesting technology, e.g. solar panels. Solar panels are currently relatively expensive because they require a time-consuming and therefore costly assembly process. As an alternative, this paper suggests a new approach to powering networked sensors: the direct integration of a solar cell onto the sensor nodes printed circuit board. This approach eliminates the need for manual assembly and the use of expensive connectors. This article presents test results and a feasibility analysis of the direct integration of a dye-sensitised solar cell onto a circuit board. Preliminary results indicate that this approach is feasible for networked sensors. The aim of this work is to develop a method for the assembly of complete systems, consisting of a printed circuit board, components, and power supply, using a single production process. The first steps towards this aim have been taken, and the authors believe that the proposed approach may be one enabling technology for future large-scale, low-cost wireless sensor networks.

  • 318.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kyusakov, Rumen
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Martinsson, Pär-Erik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    An internet of things approach for intelligent monitoring of conveyor belt rollers2013Ingår i: 10th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies 2013, CM 2013 and MFPT 2013, 2013, Vol. 2, s. 1096-1104Konferensbidrag (Refereegranskat)
  • 319.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A bluetooth-based sensor node for low-power ad hoc networks2008Ingår i: Journal of Computers, ISSN 1796-203X, E-ISSN 1796-203X, Vol. 3, nr 5, s. 1-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    TCP/IP has recently taken promising steps toward being a viable communication architecture for networked sensor nodes. Furthermore, the use of Bluetooth can enable a wide range of new applications, and in this article, an overview of the performance and characteristics of a networked sensor node based on TCP/IP and Bluetooth is presented. The number of Bluetooth-enabled consumer devices on the market is increasing, which gives Bluetooth an advantage compared to other radio technologies from an interoperability point of view. However, this excellent ability to communicate introduces disadvantages since neither TCP/IP nor Bluetooth were designed with resource-constrained sensor nodes in mind. We, however, argue that the constraints imposed by general purpose protocols and technologies can be greatly reduced by exploiting characteristics of the communication scheme in use and efficient and extensive use of available low-power modes. Furthermore, we claim that a Bluetooth-enabled networked sensor node can achieve an operating lifetime in the range of years using a total volume of less than 10 cm3. The Mulle Embedded Internet System (EIS), along with its advanced power management architecture, is presented as a case-study to support the claims.

  • 320.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Thompson, Simon J.
    Monash University, Melbourne, VIC.
    Cheng, Yi-Bing
    Monash University, Melbourne, VIC.
    A power management architecture for sensor nodes2007Ingår i: IEEE Wireless Communications & Networking Conference: WCNC 2007 ; 11 - 15 March 2007, [Hong Kong], Piscataway, NJ: IEEE Communications Society, 2007, s. 3008-3013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wireless sensor nodes are a versatile, generalpurpose technology capable of measuring, monitoring and controlling their environment. Even though sensor nodes are becoming ever smaller and more power efficient, there is one area that is not yet fully addressed; Power Supply Units (PSUs). Standard solutions that are efficient enough for electronic devices with higher power consumption than sensor nodes, such as mobile phones or PDAs, may prove to be ill suited for the extreme low-power and size requirements often found on wireless sensor nodes. In this paper, a system-level design of a Power Management Architecture (PMA) is presented. The PMA is an integration of PSU hardware and various software components, and is capable of supplying a sensor node with energy from multiple sources, as well as providing status information from the PSU. The heart of the architecture is a context- and power-aware Task manager, which controls when the nodes low-power modes are activated, and is highly integrated with PSU hardware as well as other software components in the system. Its main responsibility is to schedule when energy consuming tasks can be dispatched. Depending on the task priority and system configuration, a task can be either dispatched, discarded or delayed. This approach ensures that only critical tasks will be allowed to use the battery, and that the system will be powered by renewable energy when performing other non-critical tasks.

  • 321.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lundberg, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Time synchronous bluetooth sensor networks2006Ingår i: IEEE Consumer Communications and Networking Conference: CCNC 2006, Piscataway, NJ: IEEE Communications Society, 2006, s. 336-340Konferensbidrag (Refereegranskat)
    Abstract [en]

    Bluetooth-equipped wireless sensor nodes can be quickly integrated in small home networks. These networks can be utilized e.g. for surveillance, home monitoring and automation. Accurate time is an important factor for time-stamping of sensor data, encryption/authentication and it can also to used to implement time synchronous schemes for low power radio communication. We argue that IP-based time synchronization, such as various flavors of the NTP protocol, can be used with Bluetooth networks. This in combination with an activation schedule allows an efficient trade-off between energy consumption and communication delay, and provides easy integration with available infrastructure. The proposed approach in this paper is well suited for smaller wireless home networks, typically singlehop networks with access points that are always available. Our approach is verified by experiments performed on a COTS-based platform using Bluetooth.

  • 322.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Punal, Pablo
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Mäkitaavola, Henrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nilsson, Joakim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Gebart, Joakim
    Eistec AB.
    A Feasibility Study of SOA-enabled Networked Rock Bolts2014Ingår i: Proceedings of 2014 IEEE 19th International Conference on Emerging Technologies & Factory Automation (ETFA 2014): Barcelona, Spain, 16-19 Sept. 2014, Piscataway, NJ: IEEE Communications Society, 2014, s. 1-8, artikel-id 7005072Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of rock bolts in the mining industry is a widely used approach for increasing mine stability. However, when compared to the automation industry, where the use of sensors and real-time monitoring of processes have evolved rapidly, the use rock bolts have not changed a lot during the last 100 years. What is missing are technologies for keeping installed rock bolts under real-time and online monitoring. One problem is that rock bolts can become damaged by seismic activities or movements within the rock, and thus lose their load bearing capacity. If that happens, the outer shell of a tunnel’s walls or ceiling can collapse, with disaster as a result. Therefore, there is a clear need for online and real-time monitoring solutions for strain and thereby stress, as well as seismic activity. In this paper, the current state of art in research around intelligent rock bolts is presented. An intelligent rock bolt is the combination of a traditional rock bolt with an Internet of Things device, i.e. a rock bolt with embedded sensors, actuators, processing capabilities and wireless communication. In the proposed architecture, every rock bolt has its own IPv6 address and can establish a wireless mesh network in an ad-hoc manner. Bymeasuring strain and seismic activity and exposing the sensors in the form of services, large gains in terms of safety and efficiently can be achieved. A number of mining related activities such as stress on the rock bolt can be detected, falling rocks and the presence of mobile machinery can be observed. Since the network is based on standard communication protocols such as IPv6, it is vital to add security mechanisms to prevent eavesdropping and tampering of data traffic. By utilizing the real-time monitoring capabilities of a network of Internet-connected intelligent rock bolt, it is possible to drastically improve monitoring of mining activities and thereby providing workers with a safer working environment.

  • 323.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Johanson, Mathias
    Alkit Communications AB.
    An ad-hoc bluetooth sensor network for automotive testing2008Ingår i: 2008 Consumer Communications and Networking Conference: [IEEE CCNC 2008] ; Las Vegas, Nevada, 10 - 12 January 2008, Piscataway, NJ: IEEE Communications Society, 2008, s. 179-180Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, the feasibility of using a sensor network for automotive testing is investigated. Testing is becoming ever more important for the car industry, where the demands for quicker time-to-market and shortened development cycles are increasing. Car testing is time consuming, and is often performed in remote rural areas. Traditional methods include wiring up a vehicle with sensors connected to a data logging device. We envision that the use of wireless sensors can drastically decrease the time required to perform a set of test cases. A sensor network based on Bluetooth was used to validate our design approach. The network supports real-time monitoring of sensor data, and precludes the need of manually configuring each sensor node. Preliminary tests indicates that the proposed design is well suited for vehicle testing, due to its inherent support for ad-hoc networking and auto configuration of services.

  • 324.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Zhong, Chen
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A heterogeneous sensor network architecture for highly mobile users2011Ingår i: Proceedings of the Sixth International Conference on Wireless Communication and Sensor Networks: WCSN-2010 : December 15-19, 2010 / [ed] M.D. Tiwari; M. Radhakrishna, Piscataway, N.J: IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wireless sensor networks and personal area networks are two relatively new and emerging technologies, capable of addressing a large number of applications such as home automation, medical monitoring, and sports monitoring. This article presents a new sensor network architecture suitable for emerging applications that require a highly mobile group of persons, such as fire fighters or assault teams, to be monitored in real-time. The architecture combines features from WSN, such as mesh routing and efficient communication, with the benefits of using a PAN architecture communicating with standardized Bluetooth profiles and the TCP/IP protocol suite. The use of Bluetooth enables the proposed architecture to use a user's mobile phone in order to achieve Internet connectivity, and IEEE 802.15.4 to create an internal mesh network. This dual-radio approach is necessary since today's mobile phones lack support for radio technologies traditionally utilized by WSNs. Performed tests indicate that the approach can support dependable delivery of sensor data to the Internet from a group of highly mobile users.

  • 325.
    Emruli, Blerim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Simple principles of cognitive computation with distributed representations2012Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Brains and computers represent and process sensory information in different ways. Bridgingthat gap is essential for managing and exploiting the deluge of unprocessed andcomplex data in modern information systems. The development of brain-like computersthat learn from experience and process information in a non-numeric cognitive way willopen up new possibilities in the design and operation of both sensor and informationcommunication systems.This thesis presents a set of simple computational principles with cognitive qualities,which can enable computers to learn interesting relationships in large amounts of datastreaming from complex and changing real-world environments. More specifically, thiswork focuses on the construction of a computational model for analogical mapping andthe development of a method for semantic analysis with high-dimensional arrays.A key function of cognitive systems is the ability to make analogies. A computationalmodel of analogical mapping that learns to generalize from experience is presented in thisthesis. This model is based on high-dimensional random distributed representations anda sparse distributed associative memory. The model has a one-shot learning process andan ability to recall distinct mappings. After learning a few similar mapping examplesthe model generalizes and performs analogical mapping of novel inputs. As a majorimprovement over related models, the proposed model uses associative memory to learnmultiple analogical mappings in a coherent way.Random Indexing (RI) is a brain-inspired dimension reduction method that was developedfor natural language processing to identify semantic relationships in text. Ageneralized mathematical formulation of RI is presented, which enables N-way RandomIndexing (NRI) of multidimensional arrays. NRI is an approximate, incremental, scalable,and lightweight dimension reduction method for large non-sparse arrays. In addition, itprovides low and predictable storage requirements, and also enables the range of arrayindices to be further extended without modification of the data representation. Numericalsimulations of two-way and ordinary one-way RI are presented that illustrate whenthe approach is feasible. In conclusion, it is suggested that NRI can be used as a tool tomanage and exploit Big Data, for instance in data mining, information retrieval, socialnetwork analysis, and other machine learning applications.

  • 326.
    Emruli, Blerim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ubiquitous Cognitive Computing: A Vector Symbolic Approach2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    A wide range of physical things are currently being integrated with the infrastructure of cyberspace in a process that is creating the so-called Internet of Things. It is expected that Internet-connected devices will vastly outnumber people on the planet in the near future. Such devices need to be easily deployed and integrated, otherwise the resulting systems will be too costly to configure and maintain. This is challenging to accomplish using conventional technology, especially when dealing with complex or heterogeneous systems consisting of diverse components that implement functionality and standards in different ways. In addition, artificial systems that interact with humans, the environment and one-another need to deal with complex and imprecise information, which is difficult to represent in a flexible and standardized manner using conventional methods.This thesis investigates the use of cognitive computing principles that offer new ways to represent information and design such devices and systems. The core idea underpinning the work presented herein is that functioning systems can potentially emerge autonomously by learning from user interactions and the environment provided that each component of the system conforms to a set of general information-coding and communication rules.The proposed learning approach uses vector-based representations of information, which are common in models of cognition and semantic spaces. Vector symbolic architectures (VSAs) are a class of biology-inspired models that represent and manipulate structured representations of information, which can be used to model high-level cognitive processes such as analogy-making. Analogy-making is a central element of cognition that enables animals to identify and manage new information by generalizing past experiences, possibly from a few learned examples.The work presented herein is based on a VSA and a binary associative memory model known as sparse distributed memory. The thesis outlines a learning architecture for the automated configuration and interoperation of devices operating in heterogeneous and ubiquitous environments. To this end, the sparse distributed memory model is extended with a VSA-based analogy-making mechanism that enables generalization from a few learned examples, thereby facilitating rapid learning. The thesis also presents a generalization of random indexing, which is an incremental and lightweight feature extraction method for streaming data that is commonly used to generate vector representations of semantic spaces.The impact of this thesis is twofold. First, the appended papers extend previous theoretical and empirical work on vector-based cognitive models, in particular for analogy-making and learning. Second, a new approach for designing the next generation of ubiquitous cognitive systems is outlined, which in principle can enable heterogeneous devices and systems to autonomously learn how to interoperate.

  • 327.
    Emruli, Blerim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Gayler, Ross W.
    La Trobe University.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Analogical mapping and inference with binary spatter codes and sparse distributed memory2013Ingår i: The 2013 International Joint Conference on Neural Networks (IJCNN): Dallas, Texas 4-9 Aug 2013, Piscataway, NJ: IEEE Communications Society, 2013, s. 1-8Konferensbidrag (Refereegranskat)
    Abstract [en]

    Analogy-making is a key function of human cognition. Therefore, the development of computational models of analogy that automatically learn from examples can lead to significant advances in cognitive systems. Analogies require complex, relational representations of learned structures, which is challenging for both symbolic and neurally inspired models. Vector symbolic architectures (VSAs) are a class of connectionist models for the representation and manipulation of compositional structures, which can be used to model analogy. We study a novel VSA network for the analogical mapping of compositional structures, which integrates an associative memory known as sparse distributed memory (SDM). The SDM enables non-commutative binding of compositional structures, which makes it possible to predict novel patterns in sequences. To demonstrate this property we apply the network to a commonly used intelligence test called Raven’s Progressive Matrices. We present results of simulation experiments for the Raven’s task and calculate the probability of prediction error at 95% confidence level. We find that non-commutative binding requires sparse activation of the SDM and that 10–20% concept-specific activation of neurons is optimal. The optimal dimensionality of the binary distributed representations of the VSA is of the order 10^4, which is comparable with former results and the average synapse count of neurons in the cerebral cortex.

  • 328.
    Emruli, Blerim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Analogical mapping with sparse distributed memory: a simple model that learns to generalize from examples2014Ingår i: Cognitive Computation, ISSN 1866-9956, E-ISSN 1866-9964, Vol. 6, nr 1, s. 74-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a computational model for the analogical mapping of compositional structures that com- bines two existing ideas known as holistic mapping vec- tors and sparse distributed memory. The model enables integration of structural and semantic constraints when learning mappings of the type x_i → y_i and computing analogies x_j → y_j for novel inputs x_j. The model has a one-shot learning process, is randomly initialized and has three exogenous parameters: the dimensionality D of representations, the memory size S and the prob- ability χ for activation of the memory. After learning three examples the model generalizes correctly to novel examples. We find minima in the probability of generalization error for certain values of χ, S and the number of different mapping examples learned. These results indicate that the optimal size of the memory scales with the number of different mapping examples learned and that the sparseness of the memory is important. The optimal dimensionality of binary representations is of the order 10^4, which is consistent with a known analytical estimate and the synapse count for most cortical neurons. We demonstrate that the model can learn analogical mappings of generic two-place relationships and we calculate the error probabilities for recall and generalization.

  • 329.
    Emruli, Blerim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Vector space architecture for emergent interoperability of systems by learning from demonstration2015Ingår i: Biologically Inspired Cognitive Architectures, ISSN 2212-683X, E-ISSN 2212-6848, Vol. 11, s. 53-64Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rapid integration of physical systems with cyberspace infrastructure, the so-called Internet of Things, is likely to have a significant effect on how people interact with the physical environment and design information and communication systems. Internet-connected systems are expected to vastly outnumber people on the planet in the near future, leading to grand challenges in software engineering and automation in application domains involving complex and evolving systems. Several decades of artificial intelligence research suggests that conventional approaches to making such systems interoperable using handcrafted "semantic" descriptions of services and information are difficult to apply. In this paper we outline a bioinspired learning approach to creating interoperable systems, which does not require handcrafted semantic descriptions and rules. Instead, the idea is that a functioning system (of systems) can emerge from an initial pseudorandom state through learning from examples, provided that each component conforms to a set of information coding rules. We combine a binary vector symbolic architecture (VSA) with an associative memory known as sparse distributed memory (SDM) to model context-dependent prediction by learning from examples. We present simulation results demonstrating that the proposed architecture can enable system interoperability by learning, for example by human demonstration.

  • 330.
    Emruli, Blerim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Vector space architecture for emergent interoperability of systems by learning from demonstration2014Ingår i: Biologically Inspired Cognitive Architectures, ISSN 2212-683X, E-ISSN 2212-6848, Vol. 9, s. 33-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rapid integration of physical systems with cyberspace infrastructure, the so-called Internet of Things, is likely to have a significant effect on how people interact with the physical environment and design information and communication systems. Internet-connected systems are expected to vastly outnumber people on the planet in the near future, leading to grand challenges in software engineering and automation in application domains involving complex and evolving systems. Several decades of artificial intelligence research suggests that conventional approaches to making such systems interoperable using handcrafted "semantic" descriptions of services and information are difficult to apply. In this paper we outline a bioinspired learning approach to creating interoperable systems, which does not require handcrafted semantic descriptions and rules. Instead, the idea is that a functioning system (of systems) can emerge from an initial pseudorandom state through learning from examples, provided that each component conforms to a set of information coding rules. We combine a binary vector symbolic architecture (VSA) with an associative memory known as sparse distributed memory (SDM) to model context-dependent prediction by learning from examples. We present simulation results demonstrating that the proposed architecture can enable system interoperability by learning, for example by human demonstration.

  • 331.
    Enmark, Anita
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Datorbaserad styrning: utveckling av datorbaserat styrsystem till hydraulisk belastningsutrustning1987Rapport (Övrigt vetenskapligt)
  • 332.
    Enohnyaket, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Electromagnetic characterization of power electronic systems2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Propelled by increased global awareness and demand for clean energy systems, there is a growing trend in transportation, utility, industrial, and residential applications towards the utilisation of power electronic systems with enhanced power ow controllability and eciency. Examples of power electronics applications include terminal converters in high-voltage direct Current (HVDC) transmission; exible AC transmission systems (FACTS); and converters to interface alternative energy systems such as wind turbines to the grid, variable-speed motor drives in pump systems, vehicular propulsion systems, air-conditioners, and refrigerators.The basic functionality of power electronic components is achieved by switching high voltages and currents. Recent advancements in semiconductor technology have significantly improved the current and voltage handling capabilities and the switching frequencies of power electronic devices. However, this rapid switching of high currents and voltages in turn generates electromagnetic disturbances that could distort the functionality of the power electronic equipment and other devices in the vicinity. Electromagnetic compatibility (EMC) regulations and functionality requirements impose restrictions on the design of power electronic systems. To design robust power electronic systems, a thorough understanding of the related electromagnetic issues is required.This thesis focuses on the EMC characterisation of power electronic systems and contains two major phases.In the first phase, the high frequency characterisation of air-core reactors was considered. Air-core reactors are typically used in power systems for current limiting, ltering, shunting, and neutral grounding applications. It is of interest to understand the behaviour of air-core reactors in the presence of high frequency signals, especially from switching operations in the power electronic components. Using the partial element equivalent circuit (PEEC) approach, air-core reactor models, helpful in design and electromagnetic analysis, were created. The PEEC models were able to predict the current and voltage distributions and the eventual electromagnetic emissions at different frequencies. The second phase involved the characterisation of electromagnetic emissions from PWM drives using both modeling and measurement. A case study was performed on a prototype hybrid electric vehicle (HEV). Typically, emissions from PWM drives are expected at harmonics of the PWM switching frequency (fc) and harmonics of the fundamental frequency (f0) of the phase voltages. In this study, it was established that space vector PWM drives generate low-frequency pulsating (LFP) emissions at a frequency of 6f0. The switching of voltage vectors generates common mode current spikes because of the presence of stray capacitances and inductances. The spikes superpose across sector boundaries, forming spikes of double or triple amplitude that constitute the LFP emissions. The amplitudes of these ulsations were shown to be dependent on the drive parameters, such as the load, the speed, and the voltage slew rates. These common mode emissions enhance the emissions at harmonics of the switching frequency, create low-frequency emissions, and when injected into an electric motor, could cause torque pulsations and speed uctuations that may degrade drive functionality. Measurements from an HEV prototype show the LFP emissions, and theoretical models were developed to characterise them.

  • 333.
    Enohnyaket, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Evaluating the partial inductance routines in the LTU-PEEC solver2008Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The accuracy of partial inductance calculations is a strong determining factor in PEEC simulations. Errors in partial inductance routines lead to non-physical solutions. The sign of partial inductances depends on the assumed current directions in the conductor segments. The current flow in the structure under analysis is represented by the connectivity matrix (Cm). The signs of the entries in the Cm matrix can be chosen such that the final results from the PEEC simulations are independent of the initial current assumptions. This approach has been tested on a simple geometry. The numerical integration routines have been looked and it was seen that the existing numerical integration routines are only good for flat surfaces. In fact, the errors in the self terms approach 100% for structures with some thickness.

  • 334.
    Enohnyaket, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Generation of very low frequency beat waves from power converters2009Ingår i: 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009, Piscataway, NJ: IEEE Communications Society, 2009, s. 1025-1031Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the course of investigation of the EMI emissions from DC/AC power converters controlling synchronous machines in a hybrid electric vehicle (HEV), very low frequency beat waves were picked up in the common mode currents on the AC link. The beat wave patterns have maxima which could be more than ten percent of the phase current amplitude and at frequencies several orders lower than the switching frequency of the converters. These high currents create strong low frequency magnetic fields in the vicinity. The beat waves could potentially perturb the rotor motion and eventually distort the smooth functionality of electric machines if undamped. PSpice models show that PWM switching of converter input voltage, generates common mode current spikes (transients) due to stray capacitances, and the spikes eventually beat up. This paper presents measurements on a HEV showing beat waves, and an experimental verification of the phenomenon using an H-bridge and a DC motor.

  • 335.
    Enohnyaket, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    PEEC modeling and verification for broadband analysis of air-core reactors2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    There is an increasing utilization of modern Power Electronic (PE) devices in power systems, in for example, harmonic filters, reactive power compensation, and current limiting applications. The operational frequencies and switching rates of the PE devices now cover up to the megahertz range. As a consequence, an understanding of the functionality of static components like transformers, inductors (reactors), and capacitors in the presence of these high frequency signals are challenging issues. Present standards and legislation on EMC also put more constraints on the design of these power components. The focus of this work is the creation of high frequency electromagnetic models for power electronic components, with emphasis on air-core reactors. Attempts to model air-core reactors include lumped models, which typically consists of a series of mutually coupled lumped section, neglecting internal couplings within each section. This approach is limited to low frequencies where the voltage distribution along the turns in each section can be considered linear. For higher frequencies (several MHz), a more distributed model accounting for the electromagnetic couplings is inevitable. The Partial Element Equivalent Circuit (PEEC) modeling approach is suitable for mixed circuit and electromagnetic problems. It is based on the integral forms of Maxwell's equations upon which an equivalent circuit based model is developed. In this study, a broadband model for air-core reactors is created using the PEEC approach. Each reactor turn is represented by a finite number of interconnected bars or volume cells. From the volume cells equivalent circuit parameters, mainly the partial inductances, the coefficients of potential, and the resistances are evaluated using analytical routines. The electromagnetic coupling between the cells is represented by mutual partial inductances and the mutual coefficients of potential. The parameters are assembled into matrix equations, whose solution gives the current and voltage distribution in the model windings. The current distribution is post-processed to obtain the field distribution in the vicinity of the reactor. The PEEC reactor model was validated by comparing model results with measurements done on a laboratory air-core reactors and showed good agreement in both time and frequency domain. The time complexity for the PEEC simulation is greater compared to the corresponding lumped models, but the PEEC models give a better characterization at high frequencies. Using the frequency response from the PEEC model, smaller RLC resonance circuits replicating the same behaviour, can be synthesized. These reduced circuits can be easily included in system simulations as lumped components along side other power components. The PEEC model could also be helpful in design and diagnosis work for air-core reactors. Though the focus is on air-core reactors, the model could be enhanced to characterize other devices like power transformers.

  • 336.
    Enohnyaket, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    State of the art report on EMC characterization of hybrid drive systems2009Rapport (Övrigt vetenskapligt)
  • 337.
    Enohnyaket, Mathias
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Analysis of air-core reactors from DC to very high frequencies using PEEC models2009Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, nr 2, s. 719-729Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Faced with the challenges of increasing operational frequencies and switching rates of modern power electronics devices used in power systems, there is need for high frequency models (up to a few megahertz) for power components like reactors, capacitors banks and transformers. This paper presents the application of PEEC theory forthe creation of high frequency, electromagnetic models for air-core reactors. The electromagnetic field couplings are separated in mutual partial inductances and mutual coefficients of potential giving a correct solution from DC to a maximum frequency determined by the meshing. The PEEC models are validated by comparing simulation results, for both time and frequency domain analysis, against measurements and other established modeling methods, and show good agreement. The model created by PEEC theory, could be helpful in the design and diagnostics of air-core reactors and other power system components.

  • 338. Enohnyaket, Mathias
    et al.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    High frequency models for air-core reactors using 3D equivalent circuit theory2006Ingår i: Proceedings of Nordic Distribution and Asset Management Conference: NORDAC 2006, 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents recent advancements in creating high frequency model for air-core reactors using partial element equivalent circuit (PEEC) theory. By meshing each turn into rectangular bars, PEEC theory can be applied and the reactors can be studied in detail. Measurements results are compared to PEEC model results for the frequency domain while time domain results are presented solely for the models. It is shown that the time complexity for modeling a realistic reactor is acceptable on a regular workstation.

  • 339. Enohnyaket, Mathias
    et al.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    PEEC models for air-core reactors modeling skin and proximity effects2007Ingår i: 2007 IEEE Power Electronics Specialists Conference: [PESC 07] ; Orlando, Florida, 17 - 21 June 2007, Piscataway, NJ: IEEE Communications Society, 2007, s. 3034-3038Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a partial element equivalent circuit (PEEC) model for air-core reactors modeling skin and proximity effects at higher frequencies using the volume filament approach. Modeling results are compared to measurements in both time domain and frequency domain, and show good agreement.

  • 340. Enohnyaket, Mathias
    et al.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Three dimensional high frequency models for air-core reactors based on partial element equivalent circuit theory2006Ingår i: EMC Europe 2006 Barcelona: [International Symposium on Electromagnetic Compatibility ; September 4 - 8, 2006, Barcelona, Spain] / [ed] Ferran Silva, Barcelona: Universidad Politécnica de Cataluña , 2006Konferensbidrag (Refereegranskat)
  • 341. Enohnyaket, Mathias
    et al.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Characteristic signature of electromagnetic emissions from power converters2009Ingår i: 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009, Piscataway, NJ: IEEE Communications Society, 2009, s. 1036-1042Konferensbidrag (Refereegranskat)
    Abstract [en]

    Switching operations in power converters controlling electric machines in a hybrid drive train constitute a major source of electromagnetic related disturbances. The emissions from power converters seem to have a characteristic pattern or signature and can be picked up at different locations in the vehicle. This study aims at investigating the signature of emissions from power converters using an H-bridge driving a dc motor. PSpice model of the motor and drive circuit was made and current, voltage, and field measurements were performed on a constructed prototype. Current transients and oscillations generated during voltage transitions have been investigated using the PSpice model. A correlation between the common mode currents and the magnetic field emissions was observed.

  • 342.
    Enohnyaket, Mathias
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Parameter characterization of low frequency pulsating emissions from space vector PWM drives2011Ingår i: Proceedings of 2010 IEEE Vehicle Power and Propulsion Conference, VPPC 2010: Lille; 1 September 2010 - 3 September 2010, Piscataway, NJ: IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Power converters in hybrid electric drives constitute a major source of electromagnetic disturbances. Recent studies have established that the space vector PWM scheme commonly employed in drive systems, generates low frequency pulsating (LFP) emissions, at a frequency of 6f0, where f0 is the fundamental frequency the phase voltages. The switching of voltage vectors generates common mode current (icm) spikes due to the presence of stray capacitances and inductances. Across sector boundaries, the icm spikes superpose forming spikes of double or tipple amplitude which constitute the LFP emissions. These pulsating emissions could pose EMC issues, and functionality issues like torque pulsations and speed fluctuations that could affect the reliability of the drive. This paper investigates the effects of drive speed, load, and converter slew rates, on the amplitude of the LFP emissions, using theoretical models.

  • 343.
    Enohnyaket, Mathias
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Wisten, Åke
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Electromagnetic fields from air-core reactors using equivalent circuit theory2007Ingår i: EMB07 - the fourth Swedish conference on computational electromagnetics: methods and applications / [ed] Anders Karlsson; Gerhard Kristensson; Daniel Sjöberg, 2007, s. 69-74Konferensbidrag (Refereegranskat)
  • 344.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Embedded real-time software using TinyTimber: reactive objects in C2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Embedded systems are often operating under hard real-time constraints. Such systems are naturally described as time-bound reactions to external events, a point of view made manifest in the high-level programming and systems modeling language Timber. In this licensiate thesis we demonstrate how the Timber semantics for parallel reactive objects translates to embedded real-time programming in C. This is accomplished through the use of a minimalistic Timber Run-Time system, TinyTimber. The TinyTimber kernel ensures state integrity, and performs scheduling of events based on given time-bounds in compliance with the Timber semantics. In this way, we avoid the volatile task of explicitly coding parallelism in terms of traditional processes/threads/semaphores/monitors, and side-step the delicate task to encode time-bounds into process/thread priorities. Moreover, a simulation environment is developed that enables the behaviour of a heterogeous distributed system, consisting of both the hardware and the Timber based embedded software to be observed under a model of the environment. Furthermore, pedagogic issues of reactive objects have been studied in the context of higher education. First results indicate that the use of TinyTimber give students an increased ability to understand and solve embedded programming assignments. Finally, the TinyTimber kernel implementation is discussed. Performance metrics are given for a number of representative platforms, showing the applicability of TinyTimber to small embedded systems. A comparison to a traditional system tick driven, thread based, real-time kernel shows that TinyTimber provides tighter timing and a simpler (yet comprehensive) API. In conclution we find that the use of Reactive Objects in C, realized through TinyTimber is a viable alternative for Embedded Real-Time Programming.

  • 345.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Enabling Reactive Design of Robust Real-Time Embedded Systems2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 346.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    SRP-DM scheduling of component-based embedded real-time software2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Model and component based design is an established means for the development of large software systems, and is starting to get momentum in the realm of embedded software development. In case of safety critical (dependable systems) it is crucial that the underlying model and its realization captures the requirements on the timely behavior of the system, and that these requirements can be preserved and validated throughout the design process (from specification to actual code execution). To this end, we base the presented work on the notion of Concurrent Reactive Objects (CRO) and their abstraction into Reactive Components.In many cases, the execution platform puts firm resource limitations on available memory and speed of computations that must be taken into consideration for the validation of the system.In this paper, we focus on code synthesis from the model, and we show how specified timing requirements are preserved and translated into scheduling information. In particular, we present how ceiling levels for Stack Resources Policy (SRP) scheduling and analysis can be extracted from the model. Additionally, to support schedulability analysis, we detail algorithms that for a CRO model derives periods (minimum inter-arrival times) and offsets of tasks/jobs. Moreover, the design of a micro-kernel supporting cooperative hardware- and software-scheduling of CRO based systems under Deadline Monotonic SRP is presented.

  • 347.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Häggström, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kruglyak, Andrey
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Real-time for the masses: Step 1: programming API and static priority SRP kernel primitives2013Ingår i: 2013 8th IEEE International Symposium on Industrial and Embedded Systems (SIES 2013): 19-21 June 2013, Porto, Portugal, Piscataway, NJ: IEEE Communications Society, 2013, s. 110-113Konferensbidrag (Refereegranskat)
    Abstract [en]

    Lightweight Real-Time Operating Systems have gained widespread use in implementing embedded software on lightweight nodes. However, bare metal solutions are chosen, e.g., when the reactive (interrupt-driven) paradigm better matches the programmer’s intent, when the OS features are not needed, or when the OS overhead is deemed too large. Moreover, other approaches are used when real-time guarantees are required. Establishing real-time and resource guarantees typically requires expert knowledge in the field, as no turn-key solutions are available to the masses.In this paper we set out to bridge the gap between bare metal solutions and traditional Real-Time OS paradigms. Our goal is to meet the intuition of the programmer and at the same time provide a resource-efficient (w.r.t. CPU and memory) implementation with established properties, such as bounded memory usage and guaranteed response times. We outline a roadmap for Real-Time For the Masses (RTFM) and report on the first step: an intuitive, platform-independent programming API backed by an efficient Stack Resource Policy-based scheduler and a tool for kernel configuration and basic resource and timing analysis.

  • 348.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A comprehensive approach to design of embedded real-time software for controlling mechanical systems2007Ingår i: Asia Pacific Automotive Engineering Conference Technical Papers, Society of Automotive Engineers, Incorporated , 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a comprehensive approach to design of embedded real-time software for electrically controlled mechanical systems in automotive applications. As a case study, we implement a Gear change and Clutch controller for a Formula SAE car. This includes a generic communication interface and protocol for CAN bus communication, I/O interfaces for A/D conversion and PWM output, together with a PID controller for clutch actuation. Under our framework, the embedded software is developed using Timber, a programming language and formalism that provides executable models for embedded real-time systems. The case study shows how a complete control system can be straightforwardly modeled, simulated and transformed into executable code. The system has been realized and tested onto a lightweight, 8-bit AVR-5, embedded platform. Compared to the raw C code design flow, the proposed framework has in our case study showed increased efficiency with respect to development time. We boldly conclude that our Timber based framework offers true "work with the work".

  • 349.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A distributed engine management system for formula SAE2007Ingår i: Electronic Engine Controls: [held during the SAE 2007 world congress, April 16 - 19, 2007, Cobo Center, Detroit, MI, USA], Warrendale, Pa: Society of Automotive Engineers, Incorporated , 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper a distributed system for engine management is presented. The system is in use on the 2006 and 2005 Formula SAE cars from Luleå University of Technology. The purpose of building such a system from scratch is to have a comprehensive, predictable and easily extendable platform, giving the possibility to add extra features even at the racetrack. This allows the system to serve as a research platform for embedded real-time systems and vehicle dynamics. Another motivation is to get low weight on the complete system, and to integrate the electronics in such a way that the total cabling required will be minimal. The initial requirements are that the system should implement launch control, traction control, electric gear shift and clutch control. To control the engine the system must implement sequential fuel injection, direct fire ignition and closed loop lambda control. Moreover to remotely tune and monitor the system parameters in real-time - even on the racetrack, the system should facilitate wireless communication. To achieve these goals a system consisting of five units communicating over a standard automotive bus (CAN1) was developed. In this paper we will describe the systems functionality and the units developed.

  • 350.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nybacka, Mikael
    Larsson, Tobias
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Using Timber in a multi-body design environment to develop reliable embedded software2008Ingår i: Intelligent vehicle iniative (IVI) technology controls and navigation systems, 2008: [held during the SAE 2008 world congress, held April 14 - 17, 2008 in Detroit, Michigan, USA], Warrendale, Pa.: Society of Automotive Engineers, Incorporated , 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    A major challenge for the automotive industry is to reduce the development time while meeting quality assessments for their products. This calls for new design methodologies and tools that scale with the increasing amount and complexity of embedded systems in today's vehicles.In this paper we undertake an approach to embedded software design based on executable models expressed in the high-level modelling paradigm of Timber. In this paper we extend previous work on Timber with a multi-paradigm design environment, aiming to bridge the gap between engineering disciplines by multi-body co-simulation of vehicle dynamics, embedded electronics, and embedded executable models. Its feasibility is demonstrated on a case study of a typical automotive application (traction control), and its potential advantages are discussed, as highlighted below:shorter time to market through concurrent, co-operative distributed engineering, andreduced cost through adequate system design and dimensioning, andimproved efficiency of the design process through migration and reuse of executable software components, andreduced need for hardware testing, by specification verification on the executable model early in the design process, andimproved quality, by opening up for formal methods for verification.

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