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  • 51.
    Allahgholi, A.
    et al.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Becker, J.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Bianco, L.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Delfs, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Dinapoli, R.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Fretwurst, E.
    University of Bonn, Bonn, Germany.
    Göttlicher, P.
    University of Hamburg, Hamburg, Germany.
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media. Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Greiffenberg, D.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Gronewald, M.
    University of Bonn, Bonn, Germany.
    Hirsemann, H.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Jack, S.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Klanner, R.
    University of Bonn, Bonn, Germany.
    Klyuev, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Krüger, H.
    University of Bonn, Bonn, Germany.
    Marras, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Mezza, D.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Mozzanica, A.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Schmitt, B.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Schwandt, J.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Sheviakov, I.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Shi, X.
    Paul-Scherrer-Institut PSI, Villigen, Switzerland.
    Xia, Q.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Zhang, J.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Zimmer, M.
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    AGIPD, the electronics for a high speed X-ray imager at the Eu-XFEL2014In: Proceedings of Science, Proceedings of Science (PoS) , 2014, article id 253Conference paper (Refereed)
    Abstract [en]

    The AGIPD (Adaptive Gain Integrated Pixel Detector) X-ray imaging camera will be operated at the X-ray Free Electron Laser, Eu-XFEL, under construction in Hamburg, Germany. Key parameters are 1 million 200 μm square pixels, single 12.4 keV photon detection and a dynamic range to 10 000/pixel/image. The developed sensors, ASICs, PCB-electronics and FPGA firmware acquire individual images per bunch at 27 000 bunches/s, packed into 10 bunch-trains/s with a bunch separation of 222 ns. Bunch-trains are handled by 352 analogue storage cells within each pixel of the ASIC and written during the 0.6msec train delivery. Therefore AGIPD can store 3520 images/s from the delivered 27 000 bunches/s. Random addressing provides reusability of each cell after an image has been declared as low-quality, so that good images can be selected. Digitization is performed between trains (99.4 msec). In the paper all functional blocks are introduced. The details concentrate on the DAQ-chain PCB-electronics and the slow control. A dense area of 1024 ADC-channels, each with a pickup-noise filtering and sampling of up to 50 MS/s/ADC and a serial output of 700 Mbit/s/ADC. FPGAs operate the ASICs synchronized to the bunch structure and collect the bit streams from 64 ADCs/FPGA. Pre-sorted data is transmitted on 10 GbE links out of the camera head using the time between trains. The control and monitoring of the camera with 600 A current consumption is based on a micro-controller and I2C bus with an addressing architecture allowing many devices and identical modules. The high currents require planned return paths at the system level. First experimental experience with the constructed components will be presented.

  • 52.
    Allahgholi, A.
    et al.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Becker, J.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Bianco, L.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Delfs, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Dinapoli, R.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Goettlicher, P.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Graafsma, Heinz
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany.;Mid Sweden Univ, S-85170 Sundsvall, Sweden.
    Greiffenberg, D.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Hirsemann, H.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Jack, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Klanner, R.
    Univ Hamburg, D-20148 Hamburg, Germany..
    Klyuev, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Krueger, H.
    Univ Bonn, D-53012 Bonn, Germany..
    Lange, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Marras, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Mezza, D.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Mozzanica, A.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Rah, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Xia, Q.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Schmitt, B.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Schwandt, J.
    Univ Hamburg, D-20148 Hamburg, Germany.
    Sheviakov, I.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Shi, X.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Smoljanin, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Trunk, U.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Zhang, J.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Zimmer, M.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    AGIPD, a high dynamic range fast detector for the European XFEL2015In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 10, no 1, article id C01023Article in journal (Refereed)
    Abstract [en]

    AGIPD-(Adaptive Gain Integrating Pixel Detector) is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-Scherrer-Institut (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 10(4) 12.5keV photons, achieved by the use of the dynamic gain switching technique using 3 possible gains of the charge sensitive preamplifier. In order to store the image data, the ASIC incorporates 352 analog memory cells per pixel, allowing also to store 3 voltage levels corresponding to the selected gain. It is operated in random-access mode at 4.5MHz frame rate. The data acquisition is done during the 99.4ms between the bunch trains. The AGIPD has a pixel area of 200 x 200 m m(2) and a 500 m m thick silicon sensor is used. The architecture principles were proven in different experiments and the ASIC characterization was done with a series of development prototypes. The mechanical concept was developed in the close contact with the XFEL beamline scientists and is now being manufactured. A first single module system was successfully tested at APS.

  • 53.
    Allahgholi, A.
    et al.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Becker, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Bianco, L.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Delfs, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Gottlicher, P.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Graafsma, Heinz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Hirsemann, H.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Jack, S.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Klyuev, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Lange, S.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Marras, A.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Sheviakov, I.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Trunk, U.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Xia, Q.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Zhang, J.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Zimmer, M.
    Center for Free-Electron Laser Science, DESY, Hamburg, Germany .
    Dinapoli, R.
    PSI, Villigen, Switzerland .
    Greiffenberg, D.
    PSI, Villigen, Switzerland .
    Mezza, D.
    PSI, Villigen, Switzerland .
    Mozzanica, A.
    PSI, Villigen, Switzerland .
    Schmitt, B.
    PSI, Villigen, Switzerland .
    Shi, X.
    PSI, Villigen, Switzerland .
    Klanner, R.
    University of Hamburg, Germany .
    Schwandt, J.
    University of Hamburg, Germany .
    Gronewald, M.
    University of Bonn, Germany .
    Kruger, H.
    University of Bonn, Germany .
    Rah, S.
    Pohang Accelerator Laboratory, Pohang, South Korea .
    AGIPD 1.0: The high-speed high dynamic range readout ASIC for the adaptive gain integrating pixel detector at the European XFEL2016In: 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014, Institute of Electrical and Electronics Engineers (IEEE), 2016, article id 7431038Conference paper (Refereed)
    Abstract [en]

    AGIPD is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-Scherrer-Institute (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 104 × 12.4 keV photons, achieved by the use of dynamic gain switching, auto-selecting one of 3 gains of the charge sensitive pre-amplifier. To cope with the unique features of the European XFEL source, image data is stored in 352 analogue memory cells per pixel. The selected gain is stored in the same way and depth, encoded as one of 3 voltage levels. These memories are operated in random-access mode at 4.5MHz frame rate. Data is read out on a row-by-row basis via multiplexers to the DAQ system for digitisation during the 99.4ms gap between the bunch trains of the European XFEL. The AGIPD 1.0 ASIC features 64×64 pixels with a pixel area of 200×200 μm2. It is bump-bonded to a 500 μm thick silicon sensor. The principles of the chip architecture were proven in different experiments and the ASIC characterization was performed with a series of development prototypes. The mechanical concept of the detector system was developed in close contact with the XFEL beamline scientists to ensure a seamless integration into the beamline setup and is currently being manufactured. The first single module system was successfully tested at APS1 the high dynamic range allows imaging of the direct synchrotron beam along with single photon sensitivity and burst imaging of 352 subsequent frames synchronized to the source.

  • 54.
    Allison, Robert S.
    et al.
    York University, Centre for Vision Research, Toronto, Canada.
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology. RISE AB (Acreo).
    Chandler, Damon M.
    Shizuoka University, Hamamatsu, Shizuoka, Japan.
    Colett, Hannah R.
    Intel Corp., Santa Clara, California, United States.
    Corriveau, Philip J.
    Intel Corp., Santa Clara, California, United States.
    Daly, Scott
    Dolby Laboratories Inc., Sunnyvale, California, United States.
    Goel, James
    Qualcomm Technologies, Inc., Display Video Processing Group, Markham, Canada.
    Long, Juliana Y.
    Intel Corp., Santa Clara, California, United States.
    Wilcox, Laurie M.
    York University, Centre for Vision Research, Toronto, Canada.
    Yaacob, Yusizwan M.
    Shizuoka University, Hamamatsu, Shizuoka, Japan.
    Yang, Shun-nan
    Pacific University, Forest Grove, Oregon, United States.
    Zhang, Yi
    Xi’an Jiaotong University, School of Electronic and Information Engineering, Xi’an, China.
    Perspectives on the definition of visually lossless quality for mobile and large format displays2018In: Journal of Electronic Imaging (JEI), ISSN 1017-9909, E-ISSN 1560-229X, Vol. 27, no 5, p. 1-23, article id 053035Article in journal (Refereed)
    Abstract [en]

    Advances in imaging and display engineering have given rise to new and improved image and videoapplications that aim to maximize visual quality under given resource constraints (e.g., power, bandwidth).Because the human visual system is an imperfect sensor, the images/videos can be represented in a mathematicallylossy fashion but with enough fidelity that the losses are visually imperceptible—commonly termed“visually lossless.” Although a great deal of research has focused on gaining a better understanding ofthe limits of human vision when viewing natural images/video, a universally or even largely accepted definitionof visually lossless remains elusive. Differences in testing methodologies, research objectives, and targetapplications have led to multiple ad-hoc definitions that are often difficult to compare to or otherwise employ inother settings. We present a compendium of technical experiments relating to both vision science and visualquality testing that together explore the research and business perspectives of visually lossless image quality,as well as review recent scientific advances. Together, the studies presented in this paper suggest that a singledefinition of visually lossless quality might not be appropriate; rather, a better goal would be to establish varyinglevels of visually lossless quality that can be quantified in terms of the testing paradigm.

  • 55.
    Aloisi, Alessandro
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. University of Bologna (Italy).
    Enabling communication between Wireless Sensor Networks and The Internet-of-Things: A CoAP communication stack2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis focuses on enabling the communication between Wireless Sensor Networks and Internet-of-Things applications.  In order to achieve this goal, the first step has been to investigate the concept of the Internet-of-Things and then to understand how this scenario could be used to interconnect multiple Wireless Sensor Networks in order to develop context-aware applications which could handle sensor data coming from this type of network. 

    The second step was to design and implement a communication stack which enabled Wireless Sensor Networks to communicate with an Internet-of-Things platform. The CoAP protocol has been used as application protocol for the communication with the Wireless Sensor Networks. The solution has been developed in Java programming language and extended the sensor and actuator layer of the Sensible Things platform. 

    The third step of this thesis has been to investigate in which real world applications the developed solution could have been used. Next a Proof of Concept application has been implemented in order to simulate a simple fire detection system, where multiple Wireless Sensor Networks collaborate to send their temperature data to a control center. The last step was to evaluate the whole system, specifically the responsiveness and the overhead introduced by the developed communication stack.

  • 56.
    Alqaysi, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Evaluating Coverage Effectiveness of Multi-Camera Domes Placement for Volumetric Surveillance2017In: ICDSC 2017 Proceedings of the 11th International Conference on Distributed Smart Cameras, New York, NY, USA: Association for Computing Machinery (ACM), 2017, Vol. F132201, p. 49-54Conference paper (Refereed)
    Abstract [en]

    Multi-camera dome is composed of a number of cameras arranged to monitor a half sphere of the sky. Designing a network of multi-camera domes can be used to monitor flying activities in open large area, such as birds' activities in wind parks. In this paper, we present a method for evaluating the coverage effectiveness of the multi-camera domes placement in such areas. We used GPS trajectories of free flying birds over an area of 9 km2 to analyze coverage effectiveness of randomly placed domes. The analysis is based on three criteria namely, detection, positioning and the maximum resolution captured. The developed method can be used to evaluate results of designing and optimizing dome placement algorithms for volumetric monitoring systems in order to achieve maximum coverage.

  • 57.
    Alqaysi, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Design Exploration of Multi-Camera Dome2019In: ICDSC 2019 Proceedings of the 13th International Conference on Distributed Smart Cameras, New York, NY: ACM Digital Library, 2019, article id Article No. 7aConference paper (Refereed)
    Abstract [en]

    Visual monitoring systems employ distributed smart cameras toeffectively cover a given area satisfying specific objectives. Thechoice of camera sensors and lenses and their deployment affectsdesign cost, accuracy of the monitoring system and the ability toposition objects within the monitored area. Design cost can bereduced by investigating deployment topology such as groupingcameras together to form a dome at a node and optimize it formonitoring constraints. The constraints may include coverage area,number of cameras that can be integrated in a node and pixelresolution at a given distance. This paper presents a method foroptimizing the design cost of multi-camera dome by analyzing tradeoffsbetween monitoring constraints. The proposed method can beused to reduce monitoring cost while fulfilling design objectives.Results show how to increase coverage area for a given cost byrelaxing requirements on design constraints. Multi-camera domescan be used in sky monitoring applications such as monitoring windparks and remote air-traffic control of airports where all-round fieldof view about a point is required to monitor.

  • 58.
    Ambatipudi, Radhika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    High Frequency (MHz) Planar Transformers for Next Generation Switch Mode Power Supplies2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Increasing the power density of power electronic converters while reducing or maintaining the same cost, offers a higher potential to meet the current trend inrelation to various power electronic applications. High power density converters can be achieved by increasing the switching frequency, due to which the bulkiest parts, such as transformer, inductors and the capacitor's size in the convertercircuit can be drastically reduced. In this regard, highly integrated planar magnetics are considered as an effective approach compared to the conventional wire wound transformers in modern switch mode power supplies (SMPS). However, as the operating frequency of the transformers increase from several hundred kHz to MHz, numerous problems arise such as skin and proximity effects due to the induced eddy currents in the windings, leakage inductance and unbalanced magnetic flux distribution. In addition to this, the core losses whichare functional dependent on frequency gets elevated as the operating frequency increases. Therefore, this thesis provides an insight towards the problems related to the high frequency magnetics and proposes a solution with regards to different aspects in relation to designing high power density, energy efficient transformers.The first part of the thesis concentrates on the investigation of high power density and highly energy efficient coreless printed circuit board (PCB) step-down transformers useful for stringent height DC-DC converter applications, where the core losses are being completely eliminated. These transformers also maintain the advantages offered by existing core based transformers such as, high coupling coefficient, sufficient input impedance, high energy efficiency and wide frequencyband width with the assistance of a resonant technique. In this regard, several coreless PCB step down transformers of different turn’s ratio for power transfer applications have been designed and evaluated. The designed multilayered coreless PCB transformers for telecom and PoE applications of 8,15 and 30W show that the volume reduction of approximately 40 - 90% is possible when compared to its existing core based counterparts while maintaining the energy efficiency of the transformers in the range of 90 - 97%. The estimation of EMI emissions from the designed transformers for the given power transfer application proves that the amount of radiated EMI from a multilayered transformer is lessthan that of the two layered transformer because of the decreased radius for thesame amount of inductance.The design guidelines for the multilayered coreless PCB step-down transformer for the given power transfer application has been proposed. The designed transformer of 10mm radius has been characterized up to the power level of 50Wand possesses a record power density of 107W/cm3 with a peak energy efficiency of 96%. In addition to this, the design guidelines of the signal transformer fordriving the high side MOSFET in double ended converter topologies have been proposed. The measured power consumption of the high side gate drive circuitvitogether with the designed signal transformer is 0.37W. Both these signal andpower transformers have been successfully implemented in a resonant converter topology in the switching frequency range of 2.4 – 2.75MHz for the maximum load power of 34.5W resulting in the peak energy efficiency of converter as 86.5%.This thesis also investigates the indirect effect of the dielectric laminate on the magnetic field intensity and current density distribution in the planar power transformers with the assistance of finite element analysis (FEA). The significanceof the high frequency dielectric laminate compared to FR-4 laminate in terms of energy efficiency of planar power transformers in MHz frequency region is also explored.The investigations were also conducted on different winding strategies such as conventional solid winding and the parallel winding strategies, which play an important role in the design and development of a high frequency transformer and suggested a better choice in the case of transformers operating in the MHz frequency region.In the second part of the thesis, a novel planar power transformer with hybrid core structure has been designed and evaluated in the MHz frequency region. The design guidelines of the energy efficient high frequency planar power transformerfor the given power transfer application have been proposed. The designed corebased planar transformer has been characterized up to the power level of 50W and possess a power density of 47W/cm3 with maximum energy efficiency of 97%. This transformer has been evaluated successfully in the resonant converter topology within the switching frequency range of 3 – 4.5MHz. The peak energy efficiency ofthe converter is reported to be 92% and the converter has been tested for the maximum power level of 45W, which is suitable for consumer applications such as laptop adapters. In addition to this, a record power density transformer has been designed with a custom made pot core and has been characterized in thefrequency range of 1 - 10MHz. The power density of this custom core transformer operating at 6.78MHz frequency is 67W/cm3 and with the peak energy efficiency of 98%.In conclusion, the research in this dissertation proposed a solution for obtaining high power density converters by designing the highly integrated, high frequency(1 - 10MHz) coreless and core based planar magnetics with energy efficiencies inthe range of 92 - 97%. This solution together with the latest semiconductor GaN/SiC switching devices provides an excellent choice to meet the requirements of the next generation ultra flat low profile switch mode power supplies (SMPS).

  • 59.
    Ambatipudi, Radhika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Multilayered Coreless Printed Circuit Board (PCB) Step-down Transformers for High Frequency Switch Mode Power Supplies (SMPS)2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Power Supply Unit (PSU) plays a vital role in almost all electronic equipment. The continuous efforts applied to the improvement of semiconductor devices such as MOSFETS, diodes, controllers and MOSFET drivers have led to the increased switching speeds of power supplies. By increasing the switching frequency of the converter, the size of passive elements such as inductors, transformers and capacitors can be reduced. Hence, the high frequency transformer has become the backbone in isolated AC/DC and DC/DC converters. The main features of transformers are to provide isolation for safety purpose, multiple outputs such as in telecom applications, to build step down/step up converters and so on. The core based transformers, when operated at higher frequencies, do have limitations such as core losses which are proportional to the operating frequency. Even though the core materials are available in a few MHz frequency regions, because of the copper losses in the windings of the transformers those which are commercially available were limited from a few hundred kHz to 1MHz. The skin and proximity effects because of induced eddy currents act as major drawbacks while operating these transformers at higher frequencies. Therefore, it is necessary to mitigate these core losses, skin and proximity effects while operating the transformers at very high frequencies. This can be achieved by eliminating the magnetic cores of transformers and by introducing a proper winding structure.

    A new multi-layered coreless printed circuit board (PCB) step down transformer for power transfer applications has been designed and this maintains the advantages offered by existing core based transformers such as, high voltage gain, high coupling coefficient, sufficient input impedance and high energy efficiency with the assistance of a resonant technique. In addition, different winding structures have been studied and analysed for higher step down ratios in order to reduce copper losses in the windings and to achieve a higher coupling coefficient. The advantage of increasing the layer for the given power transfer application in terms of the coupling coefficient, resistance and energy efficiency has been reported. The maximum energy efficiency of the designed three layered transformers was found to be within the range of 90%-97% for power transfer applications operated in a few MHz frequency regions. The designed multi-layered coreless PCB transformers for given power applications of 8, 15 and 30W show that the volume reduction of approximately 40-90% is possible when compared to its existing core based counterparts. The estimation of EMI emissions from the designed transformers proves that the amount of radiated EMI from a three layered transformer is less than that of the two layered transformer because of the decreased radius for the same amount of inductance.

    Multi-layered coreless PCB gate drive transformers were designed for signal transfer applications and have successfully driven the double ended topologies such as the half bridge, the two switch flyback converter and resonant converters with low gate drive power consumption of about half a watt. The performance characteristics of these transformers have also been evaluated using the high frequency magnetic material made up of NiZn and operated in the 2-4MHz frequency region.

    These multi-layered coreless PCB power and signal transformers together with the latest semiconductor switching devices such as SiC and GaN MOSFETs and the SiC schottky diode are an excellent choice for the next generation compact SMPS.

  • 60.
    Ambatipudi, Radhika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Comparison of Two Layered and Three Layered Coreless Printed Circuit Board Step-Down Power Transformers2011In: 2011 INTERNATIONAL CONFERENCE ON INSTRUMENTATION, MEASUREMENT, CIRCUITS AND SYSTEMS (ICIMCS 2011), VOL 2: FUTURE COMMUNICATION AND NETWORKING, Shenzhen: IEEE conference proceedings, 2011, p. 59-62Conference paper (Refereed)
    Abstract [en]

    In this paper the comparative results of two layered and three layered coreless Printed Circuit Board (PCB) step down 2:1 power transformers operating in MHz frequency were addressed. The  two different step down transformers approximately having same self inductances, one in two layer and the other in three layer were designed and evaluated for the given power transfer application. The performance characteristics of these transformers under similar conditions were measured and the comparative parameters of these transformers in terms of their resistances, self, leakage, mutual inductances, and coupling coefficient are analyzed. For the given output power, the measured energy efficiency of the three layered transformer is improved by 3% and the area is reduced by 32% compared to two layered transformer. The efficiency of the three layered transformer is 94.5% approximately for an output power level of 25W at an operating frequency of 2.5MHz

  • 61.
    Ambatipudi, Radhika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Coreless Printed Circuit Board (PCB) StepdownTransformers for DC-DC ConverterApplications2010In: PROCEEDINGS OF WORLD ACADEMY OF SCIENCE, ENGINEERING AND TECHNOLOGY, ISSUE 70, OCTOBER 2010, ISSN:1307-6892, France: World Academy of Science Engineering and Technology , 2010, p. 380-389Conference paper (Refereed)
    Abstract [en]

    In this paper, multilayered coreless printed circuit board (PCB) step-down power transformers for DC-DC converter applications have been designed, manufactured and evaluated. A set of two different circular spiral step-down transformers were fabricated in the four layered PCB. These transformers have been modelled with the assistance of high frequency equivalent circuit and characterized with both sinusoidal and square wave excitation. This paper provides the comparative results of these two different transformers in te rms of their resistances, self, leakage, mutual inductances, coupling coefficient and also their energy efficiencies. The operating regions for optimal performance of these transformers for power transfer applications are determined. These transformers were tested for the output power levels of about 30 Watts within the input voltage range of 12-50 Vrms. The energy efficiency for these step down transformers is observed to be in the range of 90%-97% in MHz frequency region.

  • 62.
    Ambatipudi, Radhika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Effect of Air Gap on the Performance of Hybrid Planar Power Transformer in High Frequency (MHz) Switch Mode Power Supplies (SMPS)2012In: Proceedings of INDUCTICA 2012, Coil Winding, Insulation and Electrical Manufacturing International Conference and Exhibition (CWIEME), Berlin, Germany 26-28 June 2012, 2012Conference paper (Refereed)
    Abstract [en]

    A half bridge transformer with novel winding strategy was designed and tested up to the output power level of 50W with a maximum energy efficiency of 98% in 1-6 MHz frequency region. In this paper, the effect of air gap on the performance of the designed transformer for high frequency (MHz) Switch Mode Power Supplies (SMPS) was studied and analyzed. The air gap of the transformer was varied from 0 – 2mm and the effect on self, leakage, mutual inductances, coupling coefficient and power transfer capability was recorded in 1 - 6MHz. The parameters of the transformer with different air gaps were extracted using network analyzer. The transformer was excited with sinusoidal voltages using power amplifier and the performance characteristics such as input impedance, power transfer capability and hence the energy efficiency was measured. At a particular operating frequency of 3MHz, the maximum power transferred for the given excitation voltage with 0mm air gap was found to be 22W whereas it is only 8W with the 2mm air gap . The measured energy efficiency of the transformer at 3MHz with 0mm and 2mm air gap was found to be 93% and 79% respectively. With this study, for the given power transfer application, at a particular high frequency operation of converter, an optimum air gap without sacrificing the energy efficiency and core saturation was proposed

  • 63.
    Ambatipudi, Radhika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Effect of Dielectric Material on the Performance of Planar Power Transformers in MHz Frequency Region2012In: Proceedings of INDUCTICA 2012, Coil Winding, Insulation and Electrical Manufacturing International Conference and Exhibition (CWIEME), Berlin, Germany 26-28 June 2012, 2012Conference paper (Refereed)
    Abstract [en]

    In this paper, the effect of two different dielectric materials in planar printed circuit board (PCB) transformers applicable for power transfer applications in MHz frequency region is discussed. The 2-D model of the planar transformer was developed and the effect of the dielectric material on the magnetic field and the current distribution in the transformer was analyzed. Based on the FEA analysis, the power transformers of two different dielectric materials were designed, manufactured and characterized by using ‘S’ parameters obtained from network analyzer in order to determine the performance of dielectrics at high frequencies. The electrical parameters such as inductances, capacitances and resistances of the transformers were obtained and the changes in these parameters with the variation of the dielectric material were analyzed in the MHz frequency. This paper discusses the effect of dielectric material on the magnetic field distribution and the current density which results in the variation of the coupling coefficient and the eddy current losses of the transformer. By changing the dielectric material from a traditional FR-4 to a Rogers, the coupling coefficient was improved by a maximum of 5% and the copper losses of transformer were also decreased in the MHz frequency region. The power gain/energy efficiency obtained from the network analyzer with a resonant capacitor is verified with those obtained using a power amplifier and the simulations. An overall energy efficiency improvement of about 2-5% was achieved with a Rogers’s material in MHz frequency region compared to traditional FR-4 laminate.

     

  • 64.
    Ambatipudi, Radhika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    High Performance Planar Power Transformer with High Power Density in MHz Frequency Region for Next Generation Switch Mode Power Supplies2013In: 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference And Exposition (APEC 2013), IEEE conference proceedings, 2013, p. 2139-2143Conference paper (Refereed)
    Abstract [en]

    The authors report the utilization of the core based transformer for power transfer applications with high power density and high energy efficiency in the MHz frequency region. A custom made POT core center tapped transformer of 4:1:1 turn’s ratio using novel winding strategy with the core diameter of 16mm is designed and evaluated. The designed transformer has been characterized using sinusoidal excitation for a given output power in the frequency range of 1 – 10MHz and determined the operating frequency region of the transformer. The power tests of the transformer has been carried out up to the power level of 62W at an operating frequency of 6.78MHz with a peak energy efficiency of 98.5% resulting in the record power density of ~1100W/in3. The designed transformer has been characterized using class E isolated DC-DC converter topology at an output power of approximately 18W. The simulated energy efficiency of the converter is 88.5% under the full load condition. This work provides the significant step for the development of next generation high power density isolated converters (both AC/DC and DC/DC) in MHz frequency region

  • 65.
    Ambatipudi, Radhika
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Radiated Emissions of Multilayered Coreless Printed Circuit Board Step-Down Power Transformers in Switch Mode Power Supplies2011In: 8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia 2011, IEEE conference proceedings, 2011, p. 960-965Conference paper (Refereed)
    Abstract [en]

    This paper addressesradiatedEMI issues in Coreless PCB step-down transformers used for power transfer applications. In case of SMPS circuits, since the waveforms are not sinusoidal in nature, most of theradiatedemissionsare not only from fundamental frequency component but also from harmonic contents. According to antenna theory,radiatedEMI for three different power transformers of different radii were estimated for fundamental frequency of 2MHz to 300MHz. The computations were made for both sinusoidal and square wave excitations and at a load power of 20W. The calculatedradiatedpower obtained for simulated waveforms and for practical measured current waveforms are in good agreement with each other up to certain bandwidth. These computational results confirm thatradiatedpower can be reduced in three layered 2:1 transformer compared to two layered 2:1 transformer. Also theradiatedemissionsare negligible in case of sinusoidal excitations compared to square wave excitations. © 2011 IEEE.

  • 66.
    Amir, Yousaf Muhammad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    High Precision Laser Scanning of Metallic Surfaces2017In: International Journal of Optics, ISSN 1687-9384, E-ISSN 1687-9392, article id 4134205Article in journal (Refereed)
    Abstract [en]

    Speckle noise, dynamic range of light intensity, and spurious reflections are major challenges when laser scanners are used for 3D surface acquisition. In this work, a series of image processing operations, that is, Spatial Compound Imaging, High Dynamic Range Extension, Gray Level Transformation, and Most Similar Nearest Neighbor are proposed to overcome the challenges coming from the target surface. A prototype scanner for metallic surfaces is designed to explore combinations of these image processing operations. The main goal is to find the combination of operations thatwill lead to the highest possible robustness andmeasurement precision at the lowest possible computational load. Inspection of metallic tools where the surface of its edge must be measured at micrometer precision is our test case. Precision of heights measured without using the proposed image processing is firstly analyzed to be +/- 7.6 mu m at 68% confidence level. The best achieved height precision was +/- 4.2 mu m. This improvement comes at 24 times longer processing time and five times longer scanning time. Dynamic range extension of the image capture improves robustness since the numbers of saturated or underexposed pixels are substantially reduced. Using a high dynamic range (HDR) camera offers a compromise between processing time, robustness, and precision.

  • 67.
    Amoura, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Nätverksemulatorer: Nätverksemulering i utbildningssyfte2015Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This is a project that deals with network emulators for training purposes, where everything is based on open-source applications. The goal of this project was to evaluate GNS3 and CORE emulators and answer the question, if and how they can be used in educational purposes for students and teachers. The study begins by briefly describing the various emulators available through open-source, where it was chosen to focus on the following network emulators IMUNES: Marionnet, Mininet, NetKit, GNS3 and CORE. The evaluation was conducted using a form, and GNS3 and CORE emulators run on a Linux-based operating systems to test all functions and various applications available within the tools. The results showed that both emulators work great to make use of open-source applications that can emulate router functions to emulate network topologies with different routing protocols such as RIP, OSPF and BGP. The evaluation also showed that both emulators are excellent tools to be used by people with minimal knowledge in programming, because of its user-friendly interface that helps one to build complex topologies using drag-and-drop functionality only. The conclusion of the study is that both emulators work well for educational purposes to develop network technology, router protocols and Linux skills for students, as well as to create a virtual environment to develop their skills with which they also can experiment with their skills. To install the network emulators GNS3 and CORE and related applications took about 30 minutes per tool, as well as taking GNS3 23 MB and Core 10MB hard disk space to be installed without any accessory applications.

    Why these two tools work well for training purposes is that both emulators has integrated support for a large numbers of applications and the use of simple user interface to emulate network environments. In addition, the tools are completely free to all students and teachers, therefore everyone have the same opportunities to access them. The report recommendation is to use the emulator CORE precisely because the utility has so many features integrated within itself, and it is such a simple tool to use.

  • 68.
    An, Siwen
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Norlin, Börje
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Comparison of Elemental Analysis Techniques for Fly Ash from Municipal Solid Waste Incineration using X-rays and Electron Beams2019In: IOP Conference Series: Earth and Environmental Science, Institute of Physics (IOP), 2019, Vol. 337, no 1, article id 012007Conference paper (Refereed)
    Abstract [en]

    With the rapid expansion of the waste incineration business both in Europe and globally, there is a growing need for the elemental analysis for fly ash from municipal solid waste incineration. In this work, samples of washed and unwashed ash from municipal solid waste incineration in Sundsvall are evaluated. Qualitative analysis and semi-quantitative analysis are used to compare two elemental analysis methods, scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) measurement. Both methods are used to retrieve the difference in elemental composition between washed and unwashed fly ash. SEM-EDS accurately detects light elements from well-prepared samples in a vacuum environment, while, for online measurements, XRF is a potential method that analyses hazardous metal content in the fly ash. 

  • 69.
    Andersson, Henrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Development of Process Technology for Photon Radiation Measurement Applications2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents work related to new types of photo detectors and their applications. The focus has been on the development of process technology and methods by means of experimentation and measurements. The overall aim has been to develop and improve photon radiation measurement applications which are possible to manufacture using standard Si processing technology.

    A new type of position sensitive detector that has switching possibilities based on the MOS principle has been fabricated and characterized. The influence of mechanical stress on the linearity of position sensitive detectors has been investigated. The results show that mechanical stress arising, for example, by the mounting of detectors in capsules can have an impact on device performance. Under normal circumstances these effects are rather small, but are considered to be worthwhile taking into account.

    Electroless deposition of Nickel including various dopants in porous silicon was performed to manufacture electrical contacts for this interesting material. After heat treatment it was confirmed by X-ray diffraction that Nickel silicide had been formed and I-V measurements show that different contacts exhibit Ohmic and rectifying behaviour.

    Spectrometers are used extensively in the process and food industry to measure both the chemical content and the amount of substances used during manufacturing. These instruments are often rather bulky and costly, though the trend is towards smaller and more portable equipment. A spectrometer based on an array of Fabry-Perot interferometers mounted close to an array detector is shown to be a viable option for the manufacture of a very compact device. Such a device has minimal intermediate optics and it may be possible, in the future, for it to be developed and completely integrated with a detector array into a single unit.

  • 70.
    Andersson, Henrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Position Sensitive Detectors: Device Technology and Applications in Spectroscopy2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the development, processing and characterization of position sensitive detectors and, in addition, to the development of compact and cost effective spectrometers.

    Position sensitive detectors are used to measure, with great accuracy and speed, the position of a light spot incident on the surface. Their main use is for triangulation, displacement and vibration measurements.

    A type of position sensitive detector based on the MOS principle and using optically transparent indium tin oxide as a gate contact has been developed. This type of detector utilizes the MOS principle where an induced channel forms beneath the gate oxide in the surface of the Silicon substrate.

    One and two dimensional detectors have both been fabricated and characterized. The first measurements showed that the linearity did not fulfil expectations and it was suspected that stress induced by the gate contact could be the reason for the seemingly high nonlinearity.

    Further investigations into both the p-n junction and the MOS type position sensitive detectors lead to the conclusion that the indium tin oxide gate is responsible for inducing a substantial stress in the surface of the detector, thus giving rise to increased position nonlinearity. The heat treatment step which was conducted was determined to be critical as either a too short or too long heat treatment resulted in stress in the gate and channel leading to position nonlinearity. If a correctly timed heat treatment is performed then the detector’s linearity is in parity with the best commercial position sensitive detectors.

    In addition, the development of very small, compact and cost effective spectrometers has been performed with the aim of constructing devices for use in the process industry. The development of a wedge shaped array of Fabry-Perot interferometers that can be mounted directly on top of a detector makes it possible to construct a very compact spectrometer using the minimum amount of optics. This wedge interferometer has been evaluated by means of array pixel detectors and position sensitive detectors for both the infrared and the visible wavelength ranges.

    When used with a position sensitive detector it is necessary to use a slit to record the intensity of the interferogram for many points over the detector, equivalent to pixels on an array detector. Usually the use of moving parts in a spectrometer will impose the use of high precision scanning mechanisms and calibration. By using a position sensitive detector for the interferogram readout both the position and the intensity are known for every measurement point and thus the demands placed on the scanning system are minimized.

  • 71.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Processing and Characterization of a MOS Type Tetra Lateral Position Sensitive Detector with Indium Tin Oxide Gate Contact2008In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 8, no 9-10, p. 1704-1709Article in journal (Refereed)
    Abstract [en]

    A 2-D tetra lateral position sensitive detector (PSD) based on the metal-oxide-semiconductor (MOS) principle has been manufactured and characterized. The active area of the device is 5 nun x 5 mm and the intention is to use the central 4 nun x 4 nun for low nonlinearity measurements. The gate contact is made of indium tin oxide (ITO) that is a degenerate electrically conducting semiconductor, which, in addition, is also transparent in the visible part of the spectrum. The use of a MOS structure results in a processing with no necessity to use implantation or diffusion in order to make the resistive p-layer as in a conventional p-n junction lateral effect PSD. Position measurements show good linearity in the middle 4 nun x 4 mm area. Within the middle 2.1 mm x 2.1 mm, the nonlinearity is within 1.7% of the active area with a position detection error of maximum 60 mu m. Measured MOS IV characteristics are compared to a level 3 spice model fit and show good agreement. The threshold voltage is determined to be -0.03 V. Responsivity measurements show a high sensitivity in the visible spectral region.

  • 72.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bylund, Nicklas
    CTRR, AB Sandvik Coromant.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Analysis and improvement of the position nonlinearity caused by a residual stress in MOS-type position-sensitive detectors with indium tin oxide gate contact2008In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 23, no 7, p. 1-10Article in journal (Refereed)
    Abstract [en]

    In this paper, lateral effect position-sensitive detectors based on the MOS principle have been fabricated in lengths of 15 mm, 45 mm and 60 mm. The gate contact covering the active area consists of indium tin oxide which is a degenerate semiconductor transparent in the visible spectral range. Characterization and analysis have both been performed especially withparticular focus on the nonlinearity believed to be caused by stray stress induced in the inversion channel originating in the indium tin oxide gate contact. Stress in the channel will change the resistance in a non-uniform manner because of the piezoresistance effect, thus causing a nonlinearity in the position determination. It has been shown that the heat treatmentgreatly influences the linearity of the position-sensitive detectors. A heat treatment performed correctly results in 60 mm and 15 mm detectors with nonlinearity within ±0.1% and 45 mm detectors with nonlinearity within ±0.15% over 60% of the active length. This is an improvement over the previous results with this type of MOS position-sensitive detector. By performing a correctly timed heat treatment this PSD type has the potential to be used incommon position-sensing applications.

  • 73.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hammarling, Krister
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sidén, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Modified EAS Tag Used as a Resistive Sensor Platform2012In: MDPI Electronics, ISSN 2079-9292, Vol. 1, no 2, p. 32-46Article in journal (Refereed)
    Abstract [en]

    In this article, a modified design of an RF Radio Frequency Electronic ArticleSurveillance (EAS) tag, used as a sensor platform, is manufactured and characterized. EAStags are passive devices consisting of a capacitor and coil, tuned to a resonance frequencyreadable by the detector equipment, in this case 8.2 MHz. They were originally used todetect whether merchandise was being moved through the detection gates at shop exits, inwhich case an alarm was triggered. If the capacitance is divided in two and a resistivesensor device inserted in between, the resonant Inductor-Capacitor (LC) circuit becomes anInductor-Capacitor-Capacitor-Resistor LCCR circuit and can be used as a sensor tag. Ahigh sensor resistance means that one capacitor is decoupled, leading to one resonancefrequency, while a low resistance will couple both capacitances into the circuit, resulting ina lower resonance frequency. Different types of resistive sensors exist that are able todetect properties such as pressure, moisture, light and temperature. The tag is manufacturedin Aluminum foil on a polyetylentereftalat (PET) substrate, resulting in a cost effectiveRF-platform for various resistive sensors. Two types of tags are designed andmanufactured, one with parallel plate capacitors and the other with interdigital capacitors.To test the tags, a resistive tilt sensor is mounted and the tags are characterized using anetwork analyzer. It is shown that for high resistance, the tags have a resonance frequencyof more than 10 MHz while for low values the frequency approaches 8.2 MHz.

  • 74.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Gao, Jinlan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lidenmark, Cecilia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sidén, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Unander, Tomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Dewire AB, Sundsvall 85185, Sweden.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Investigation of Humidity Sensor Effect in Silver Nanoparticle Ink Sensors Printed on Paper2014In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 14, no 3, p. Art. no. 6615915-Article in journal (Refereed)
    Abstract [en]

    Thin inkjet-printed tracks of silver nanoparticles have previously been observed to show a non-reversible decrease in resistance when exposed to a high degree of relative humidity and thus providing sensor functionality with a memory effect. This paper provides a more in-depth explanation of the observed humidity sensor effect that originates from inkjet-printed silver nanoparticle sensors on a paper substrate. It is shown that the geometry of the sensor has a large effect on the sensor's initial resistance, and therefore also on the sensor's resistive dynamic range. The importance of the sensor geometry is believed to be due to the amount of solvent from the ink interacting with the coating of the paper substrate, which in turn enables the diffusion of salts from the paper coating into the ink and thus affecting the silver ink.

  • 75.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Lundgren, Anders
    SiTek Electro Opt, S-43330 Partille, Sweden.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Principle of FT Spectrometer based on a Lateral Effect Position Sensitive Detector and Multi Channel Fabry-Perot Interferometer2009In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 42, no 5, p. 668-671Article in journal (Refereed)
    Abstract [en]

    The principle of a new type of multi channel Fourier-Transform spectrometer based on a multi channel wedge Fabry-Perot interferometer using a one dimensional lateral effect Position Sensitive Detector and a scanning slit for interferogram readout have been shown. The design of this spectrometer is very compact and the readout electronics very simple. The drawback of using a scanning slit system is minimized by the use of a position sensitive detector where the position is inherently known for each measurement. Experiments show that the position can be resolved with high accuracy and the summation of the two photocurrents gives the interferogram after scanning the slit between the wedge interferometer and the position sensitive detector. The spectral resolution obtained with a 25mm wedge interferometer together with a 45mm position sensitive detector and a 25µm slit is about 5nm around 600nm wavelength range, which is close to the theoretically anticipated resolution. The evaluated spectrometer setup show promising results and could be used in applications where compact and low cost spectrometers are required.

  • 76.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Broadband Parameters of Compact FT Spectrometer based on Fabry-Perot Interferometer Integrated with detector2008Conference paper (Refereed)
  • 77.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Evaluation of an Integrated Fourier-Transform Spectrometer Utilizing a Lateral Effect Position Sensitive Detector with a Multi-Channel Fabry-Perot Interferometer2008In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 19, no 4, p. 045306-Article in journal (Refereed)
    Abstract [en]

    The basis of this paper is the evaluation of an integrated multi-channel Fourier-transform (FT) spectrometer based on a multi-channel wedge Fabry-Perot interferometer and a one-dimensional lateral effect position sensitive detector (PSD). The use of a PSD for an interferogram readout allows for a simple scanning mechanism with no requirement for any position reference. The use of a wedge-shaped interferometer makes it possible to integrate it directly onto the PSD surface, thus producing a very compact spectrometer. The capabilities of the spectrometer are demonstrated by absorption spectral measurements using a reference sample. In addition, spectral measurements on 532 nm DPSS and 632.8 nm He-Ne lasers are presented. The resolution of the spectrometer is approximately 5 nm. The evaluated spectrometer set-up can be used in applications where compact and low cost spectrometers are required, such as in process control and in education. Further, it is shown that there are deteriorations in very high accuracy position measurements, which are caused by changes in incident light intensity. A model describing the above-mentioned nonlinearities was developed based on analysing the equivalent circuit for PSDs and parameters such as leakage current and serial resistance. Additionally, a method is proposed to assist in the reduction of the nonlinearity caused by this effect.

  • 78.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Mattsson, Claes
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Lundgren, Anders
    SiTek Electro Optics.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    The effect of mechanical stress on lateral-effect position sensitive detector characteristics2006In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 563, no 1, p. 150-154Article in journal (Refereed)
    Abstract [en]

    Position-sensitive detectors (PSDs) are widely used in noncontact measurement systems. In order to minimize the size of such systems, interest has increased in mounting the PSD chip directly onto printed circuit boards (PCBs). Stress may be induced in the PSD because of the large differences in thermal expansion coefficients, as well as the long-term geometrical stability of the chip packaging. Mechanical stress has previously been shown to have an effect on the performance of semiconductors. The accuracy, or linearity, of a lateral effect PSD is largely dependent on the homogeneity of the resistive layer. Variations of the resistivity over the active area of the PSD will result in an uneven distribution of photo-generated current, and hence an error in the readout position. In this work experiments were performed to investigate the influence of anisotropic mechanical stress in terms of nonlinearity. PSD chips of 60×3 mm active area were subjected, respectively, to different amounts of compressive and tensile stress to determine the influence on the linearity.

  • 79.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Sidén, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Skerved, Vincent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Li, Xiaotian
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Gyllner, Linnea
    Iniss Triab AB, S-16250 Vällingby.
    Soldering Surface Mount Components onto Inkjet Printed Conductors on Paper Substrate using Industrial Processes2016In: IEEE Transactions on Components, Packaging, and Manufacturing Technology, ISSN 2156-3950, E-ISSN 2156-3985, Vol. 6, no 3, p. 478-485, article id 7422029Article in journal (Refereed)
    Abstract [en]

    This paper describes mounting of standard surface mount component packages on a paper substrate using an industrial solder process with a low-temperature solder. The use of paper as a substrate for printed flexible electronics is becoming more and more widespread as an alternative to the more commonly used plastic substrates, such as polyethylene and polyimide. Paper has the benefits of being environmentally friendly, recyclable, and renewable, as well as inexpensive. It is shown that it is possible to mount standard surface mount device components on paper substrates using low-temperature solder in an industrial soldering process. The contact resistances obtained are mostly low, although the yield of functioning contacts is low. The reason is cracking of the substrate coating layer that goes through the printed silver tracks. It was observed that the cracks appear mostly close to the contact pads, the most likely cause is thermal mismatch between the coating layer and solder and also thermal expansion of the photo paper resin coating. The smallest component package size, 0201, resulted in the highest yield of >80% with decreasing yield for larger package sizes.

  • 80.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Lundgren, A.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Processing and characterization of a position sensitive lateral-effect metal oxide semiconductor detector2004In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 531, no 1-2, p. 140-146Article in journal (Refereed)
    Abstract [en]

    Position sensingdetectors (PSDs) are useful in many applications, such as vibration, displacement, and triangulation measurements. In this paper we present a lateral-effect metal oxide semiconductor PSD with switchingcapability fabricated by our group. The detector can be switched off by the application of 0V on the substrate and 0.2V on the gate. A linear current-position behaviour is exhibited by the detector at a substrate bias of both 5 and 10V with the gate at 0V. There is no effect on the linearity when the substrate voltage is changed from 5 to 10V. The non-linearity is within 0.2% at a distance of 71.5mm from origin for 5, 10 and 15mm device length.

  • 81.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Electroless deposition and silicidation of Ni contacts into p-type Porous Silicon2008In: Journal of porous materials, ISSN 1380-2224, E-ISSN 1573-4854, Vol. 15, no 3, p. 335-341Article in journal (Refereed)
    Abstract [en]

    Porous Silicon (PS) has attracted much attention since the discovery of its photo luminescent behavior. It has also been used for various other applications such as electroluminescent light emitting-diodes (LEDs), photodetectors and solar cells. For such devices, it is important to make good metallic Ohmic contacts to the PS in order to maximize the efficiency. In order to produce buried contacts, barrier layers, Schottky devices, etc. in PS, it is advantageous to deposit metal that covers not only the surface of the porous layer, but also the inside walls and the bottom of the pores. In this work experiments were performed to examine the morphology and properties of electroless deposition of Nickel into p-type PS and subsequent formation of Nickel silicide after heat treatment. Circular PS samples of 6 mm diameter were produced by anodizing p-type Silicon wafers for 15 min and were subsequently plated with Ni using three different plating baths. The pores are on average 20 µm deep and 4 µm wide. Two samples of each type were heat treated in an nitrogen atmosphere for one hour at 400 and 600°C respectively to produce Nickel silicide. Reference samples were made by means of electron beam evaporation of Ni. SEM micrographs show that the best pore coverage was achieved using the Ni plating bath containing hypophosphite. I–V characterization shows that different rectifying and Ohmic contacts can be formed between electroless deposited Ni and PS depending on the conditions of the heat treatment. XRD and EDX characterizations show that both the NiSi and Ni2Si phases exist in the sample at the same time.

  • 82.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Örtegren, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Evaluation of InkAid surface treatment to enhance print quality of ANP silver nano-particle ink on plastic substrates2010In: Large Area, Organic & Printed Electronics (LOPE-C) 2010, Frankfurt, 2010, p. 241-245Conference paper (Refereed)
  • 83.
    Andersson, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    3D Video Playback: A modular cross-platform GPU-based approach for flexible multi-view 3D video rendering2010Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The evolution of depth‐perception visualization technologies, emerging format standardization work and research within the field of multi‐view 3D video and imagery addresses the need for flexible 3D video visualization. The wide variety of available 3D‐display types and visualization techniques for multi‐view video, as well as the high throughput requirements for high definition video, addresses the need for a real‐time 3D video playback solution that takes advantage of hardware accelerated graphics, while providing a high degree of flexibility through format configuration and cross‐platform interoperability. A modular component based software solution based on FFmpeg for video demultiplexing and video decoding is proposed,using OpenGL and GLUT for hardware accelerated graphics and POSIX threads for increased CPU utilization. The solution has been verified to have sufficient throughput in order to display 1080p video at the native video frame rate on the experimental system, which is considered as a standard high‐end desktop PC only using commercial hardware. In order to evaluate the performance of the proposed solution a number of throughput evaluation metrics have been introduced measuring average frame rate as a function of: video bit rate, video resolution and number of views. The results obtained have indicated that the GPU constitutes the primary bottleneck in a multi‐view lenticular rendering system and that multi‐view rendering performance is degraded as the number of views is increased. This is a result of the current GPU square matrix texture cache architectures, resulting in texture lookup access times according to random memory access patterns when the number of views is high. The proposed solution has been identified in order to provide low CPU efficiency, i.e. low CPU hardware utilization and it is recommended to increase performance by investigating the gains of scalable multithreading techniques. It is also recommended to investigate the gains of introducing video frame buffering in video memory or to move more calculations to the CPU in order to increase GPU performance.

  • 84.
    Andersson, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Parallel Simulation: Parallel computing for high performance LTE radio network simulations2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Radio access technologies for cellular mobile networks are continuously being evolved to meet the future demands for higher data rates, and lower end‐to‐end delays. In the research and development of LTE, radio network simulations play an essential role. The evolution of parallel processing hardware makes it desirable to exploit the potential gains of parallelizing LTE radio network simulations using multithreading techniques in contrast to distributing experiments over processors as independent simulation job processes. There is a hypothesis that parallel speedup gain diminishes when running many parallel simulation jobs concurrently on the same machine due to the increased memory requirements. A proposed multithreaded prototype of the Ericsson LTE simulator has been constructed, encapsulating scheduling, execution and synchronization of asynchronous physical layer computations. In order to provide implementation transparency, an algorithm has been proposed to sort and synchronize log events enabling a sequential logging model on top of non‐deterministic execution. In order to evaluate and compare multithreading techniques to parallel simulation job distribution, a large number of experiments have been carried out for four very diverse simulation scenarios. The evaluation of the results from these experiments involved analysis of average measured execution times and comparison with ideal estimates derived from Amdahl’s law in order to analyze overhead. It has been shown that the proposed multithreaded task‐oriented framework provides a convenient way to execute LTE physical layer models asynchronously on multi‐core processors, still providing deterministic results that are equivalent to the results of a sequential simulator. However, it has been indicated that distributing parallel independent jobs over processors is currently more efficient than multithreading techniques, even though the achieved speedup is far from ideal. This conclusion is based on the observation that the overhead caused by increased memory requirements, memory access and system bus congestion is currently smaller than the thread management and synchronization overhead of the proposed multithreaded Java prototype.

  • 85.
    Andersson, Karl
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Intelligent control system for street lighting2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Street lighting is an important aspect of infrastructure in terms of both safety and comfort, but it also consumes a lot of energy. Unused light is a waste of energy, and without any form of control of the street lighting, this problem will continue to increase along with the expansion of road networks. The aim of this thesis is to propose an intelligent control system for street lighting that can adapt to the velocity of individual road users, to investigate if this could provide ways to improve the efficiency of street lighting. Previous control approaches include systems based on ambient light intensity or presence of road users, but no studies were found in which illumination adapts to the velocity of road users. The project involves three main steps, including a literature review, a system implementation and evaluation. In the proposed system, street lights cooperate to detect road users and calculate their velocities in order to adapt the illumination and make it follow their movement. It can be concluded from the evaluation results that the velocity readings help further optimize the illumination control in comparison to systems that do not consider velocity. The velocity readings make it possible to only illuminate the roadway in the direction of travel, while also adapting the distance of illumination to the recorded speed. The proposed control scheme is considered a viable solution for reducing the amount of unused light, consequently reducing the energy consumption of street lighting.

  • 86.
    Andersson, Karl
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    PLC Lab Station: An Implementation of External Monitoring and Control Using OPC2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The PLC is frequently used when implementing automated control, which is animportant part of many modern industries. This thesis has been carried out incollaboration with ÅF Consult in Sundsvall, who were in need of a PLC labstation for educational purposes. The overall aim of this thesis has been todesign and construct such a lab station and also to implement a solution forexternal monitoring and control possibilities. The methodology of this projecthas included a literary study, followed by the implementation of the actualsolutions and finally an evaluation of the project. The finished lab stationincludes a conveyor belt and a robotic arm controlled using two PLCs. Theconveyor belt is designed to be able to store, transport, differentiate and sortsmall cubes of various materials, and the robotic arm is designed as a pick-andplacedevice that can move the cubes between different positions on the labstation. The monitoring and control solution is set up using an OPC clientserverconnection on a PC and it provides a graphical user interface where thelab station can be monitored and controlled externally. The lab station offersdiverse functionality, but due to some inconsistency in the included equipmentit is not entirely reliable. The external monitoring and control solution alsoprovides good functionality, but the time frame of the project resulted in a lessextensive implementation than originally intended. The overall solutions are,however, considered to offer a functional and proper platform for educationalpurposes.

  • 87.
    Andresen, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Skillnader i upphandling mellan EBR och AMA2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today's Swedish power grid has a major need for renovation and upgrading, which gives a big investment requirement over the next few years. This makes it important to find new entrepreneurs in addition to those already available today. Find a way to become more attractive and interesting for these entrepreneurs. This report highlights two methods that outsourcer have to relate to. First method is Electrical Building Rationalization (EBR) and the other method is general material and work description (AMA). The system of EBR is a secure system based on long-term statistics from installations, renovations and maintenance. There the advantages of standardized components are that they are cost-effective and create a quality of work performed. AMA is a reference tool for building projects from scratch. It's freer in its structure when planning a facility. One does not need relate to more strict approach. This report looks at the differences in EBR / AMA and looks at what are good changes to attract new actors in the market. What can be changed in the future and at the same time affecting projecting design and procurement documentation.

  • 88.
    Andrén, B.
    et al.
    NetLab: Visual Media Quality, Acreo Swedish ICT AB, SE-16440 Kista, Sweden .
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. NetLab: Visual Media Quality, Acreo Swedish ICT AB, SE-16440 Kista, Sweden .
    Wang, Kun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. NetLab: Visual Media Quality, Acreo Swedish ICT AB, SE-16440 Kista, Sweden .
    Readability of displays in bright outdoor surroundings2014In: SID Symposium Digest of Technical Papers, 2014, Vol. 45, no 1, p. 1100-1103Conference paper (Refereed)
    Abstract [en]

    Readability of displays in bright outdoor surroundings is a problem for many types of visual displays. The wide range of lighting conditions that these displays should be able to operate in, makes the design of the test set-up very challenging. Mobile displays of today usually have LCDs with LED backlight or OLEDs, which gives the possibility to control the light levels from very low luminance or even zero luminance to very high luminance levels with good contrast and color rendering. There are many displays that can show high luminance (>1000 cd/m2) and with that are considered or claimed to have daylight or sunlight readability. However, these statements are rarely supported by scientific tests with test subjects. This paper will discuss and analyze the conditions for performing such experiments. Experimental results that the visual acuity is negatively affected by strong illuminance are presented.

  • 89. Andrén, Börje
    et al.
    Wang, Kun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Brunnström, Kjell
    Characterizations of 3D TV: Active vs passive2012In: SID Symposium Digest of Technical Papers 2012, Blackwell Publishing Ltd , 2012, p. 137-140Conference paper (Refereed)
    Abstract [en]

    Two different techniques are dominating the 3D TV market today i.e. active shutter glasses and passive film patterned retarder. Both the techniques have their pros and cons. In this paper we compare these two types of 3D TV3D TV by evaluating them with respect to some important visual ergonomic parameters such as angle dependent cross talk, luminance levels, flicker and resolution.

  • 90.
    Anjum, Mahnoor
    et al.
    National University of Sciences and Technology (NUST), Pakistan.
    Khan, Muhammad Abdullah
    National University of Sciences and Technology (NUST), Pakistan.
    Hassan, Syed Ali
    National University of Sciences and Technology (NUST), Pakistan.
    Mahmood, Aamir
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Gidlund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Analysis of RSSI Fingerprinting in LoRa Networks2019In: 2019 15th International Wireless Communications & Mobile Computing Conference (IWCMC), IEEE, 2019, p. 1178-1183Conference paper (Refereed)
    Abstract [en]

    Localization has gained great attention in recent years, where different technologies have been utilized to achieve high positioning accuracy. Fingerprinting is a common technique for indoor positioning using short-range radio frequency (RF) technologies such as Bluetooth Low Energy (BLE). In this paper, we investigate the suitability of LoRa (Long Range) technology to implement a positioning system using received signal strength indicator (RSSI) fingerprinting. We test in real line-of-sight (LOS) and non-LOS (NLOS) environments to determine appropriate LoRa packet specifications for an accurate RSSI-to-distance mapping function. To further improve the positioning accuracy, we consider the environmental context. Extensive experiments are conducted to examine the performance of LoRa at different spreading factors. We analyze the path loss exponent and the standard deviation of shadowing in each environment

  • 91.
    Ansari, Rafay Iqbal
    et al.
    Frederick University, Nicosia, Cyprus.
    Pervaiz, Haris
    Lancaster University, UK.
    Chrysostomou, Chrysostomos
    Frederick University, Nicosia, Cyprus.
    Hassan, Syed Ali
    National University of Sciences and Technology (NUST), Pakistan.
    Mahmood, Aamir
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Gidlund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Control-Data Separation Architecture for Dual-Band mmWave Networks: A New Dimension to Spectrum Management2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 34925-34937, article id 8663278Article in journal (Refereed)
    Abstract [en]

    The exponential growth in global mobile data traffic, especially with regards to the massive deployment of devices envisioned for the fifth generation (5G) mobile networks, has given impetus to exploring new spectrum opportunities to support the new traffic demands. The millimeter wave (mmWave) frequency band is considered as a potential candidate for alleviating the spectrum scarcity. Moreover, the concept of multi-tier networks has gained popularity, especially for dense network environments. In this article, we deviate from the conventional multi-tier networks and employ the concept of control-data separation architecture (CDSA), which comprises of a control base station (CBS) overlaying the data base station (DBS). We assume that the CBS operates on the sub-6 GHz single band, while the DBS possesses a dual-band mmWave capability, i.e., 26 GHz unlicensed band and 60 GHz licensed band. We formulate a multi-objective optimization (MOO) problem, which jointly optimizes conflicting objectives: the spectral efficiency (SE) and the energy efficiency (EE). The unique aspect of this work includes the analysis of a joint radio resource allocation algorithm based on Lagrangian Dual Decomposition (LDD) and we compare the proposed algorithm with the maximal-rate (maxRx), dynamic sub-carrier allocation (DSA) and joint power and rate adaptation (JPRA) algorithms to show the performance gains achieved by the proposed algorithm.

  • 92.
    Anwar, Qaiser
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Imran, Muhammad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Intelligence Partitioning as a Method for Architectural Exploration of Wireless Sensor Node2016In: Proceedings of the International Conference on Computational Science and Computational Intelligence (CSCI), 2016., IEEE Press, 2016, p. 935-940, article id 7881473Conference paper (Refereed)
    Abstract [en]

    Embedded systems with integrated sensing, processing and wireless communication are driving future connectivity concepts such as Wireless Sensor Networks (WSNs) and Internet of Things (IoTs). Because of resource limitations, there still exists a number of challenges such as low latency and energy consumption to realize these concepts to full potential. To address and understand these challenges, we have developed and employed an intelligence partitioning method which generates different implementation alternatives by distributing processing load across multiple nodes. The task-to-node mapping has exponential complexity which is hard to compute for a large scale system. Regarding this, our method provides recommendation to handle and minimize such complexity for a large system. Experiments on a use-case concludes that the proposed method is able to identify unfavourable architecture solutions in which forward and backword communication paths exists in task-to-node mapping. These solution can be avoided for further architectural exploration, thus limiting the space for architecture exploration of a sensor node.

  • 93.
    Anwar, Qaiser
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Malik, Abdul Waheed
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Design of coded reference labels for indoor optical navigation using monocular camera2013In: 2013 International Conference on Indoor Positioning and Indoor Navigation, IPIN 2013, IEEE Computer Society, 2013, p. Art. no. 6817925-Conference paper (Refereed)
    Abstract [en]

    We present a machine vision based indoor navigation system. The paper describes a pose estimation of machine vision system by recognizing rotationally independent optimized color reference labels combined with a geometrical camera calibration model, which determines a set of camera parameters. A reference label carries one byte of information, which can be uniquely designed for various values. More than four reference labels are used in the image to calculate the localization coordinates of the system. An algorithm in Matlab has been developed so that a machine vision system can recognize N number of labels at any given orientation. In addition, a one channel color technique is applied in segmentation process, due to this technique the number of segmented image components is reduced significantly, limiting the memory storage requirement and processing time. The algorithm for pose estimation is based on direct linear transformation (DLT) method with a set of control reference labels in relation to the camera calibration model. From the experiments we concluded that the pose of the machine vision system can be calculated with relatively high precision, in the calibrated environment of reference labels. © 2013 IEEE.

  • 94.
    Appelsved, Ivan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Dosimetry of ionizing radiation with an artificial neural network: With an unsorted, sequential input2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis the verification of a neural network’s proficiency at labeling ionizing radiation particles from the unsorted output of a timepix3 camera is attempted. Focus is put on labeling single particles in separate data sequences with slightly preprocessed input data. Preprocessing of input data is done to simplify the patterns that should be recognized. Two major choices were available for this project, Elman-network and Jordan-network. A more complicated type was not an option because of the longer time needed to implement them. The network type chosen was Elman because of freedom in context size. The neural network is created and trained with the TensorFlow API in python with labeled data that was not created by hand. The network recognized the length difference between gamma particles and alpha particles. Beta particles were not considered by the network. It is concluded that the Elman-style network is not proficient in labeling the sequences, which were considered short enough and to have simple enough input data. A more modern network type is therefore likely required to solve this problem.

  • 95.
    Aranda, Jesus Javier Lechuga
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bader, Sebastian
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    An Apparatus For The Performance Estimation Of Pressure Fluctuation Energy Harvesters2018In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 67, no 11, p. 2705-2713Article in journal (Refereed)
    Abstract [en]

    Hydraulic pressure fluctuation energy harvesters are promising alternatives to power up wireless sensor nodes in hydraulic systems. The characterization of these harvesters under dynamic and band-limited pressure signals is imperative for the research and development of novel concepts. To generate and control these signals in a hydraulic medium, a versatile apparatus capable of reproducing pressure signals is proposed. In this paper, a comprehensive discussion of the design considerations for this apparatus and its performance is given. The suggested setup enables the investigation of devices tailored for the harvesting of energy in conventional hydraulic systems. To mimic these systems, static pressures can be tuned up to 300 bar, and the pressure amplitudes with a maximum of 28 Bar at 40 Hz and 0.5 bar at 1000 Hz can be generated. In addition, pressure signals found in commercial hydraulic systems can be reproduced with good accuracy. This apparatus proves to be an accessible, robust, and versatile experimental setup to create environments for the complete performance estimation of pressure fluctuation energy harvesters. 

  • 96.
    Aranda, Jesus Javier Lechuga
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bader, Sebastian
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Force Transmission Interfaces for Pressure Fluctuation Energy Harvesters2018In: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society, IEEE, 2018, p. 4230-4235, article id 8591058Conference paper (Refereed)
    Abstract [en]

    Wireless sensor nodes in state of the art fluid power systems used in monitoring and maintenance prediction demand long lasting power sources that do not rely on batteries. Energy harvesting is a promising technology that can provide the required energy to power wireless sensors. Pressure fluctuation energy harvesters can be employed in conventional hydraulic systems to convert the acoustic pressure fluctuation to electrical power. Present studies have explored the overall efficiency of these devices while experimentally describing losses in piezoelectric and circuit interfaces, nevertheless there is no study on the fluid to mechanical force transmission efficiency. In this paper we investigate the pressure to force transmission rate of two types of fluid to mechanical interfaces: a flat metal plate and a conventional hydraulic piston. The interfaces are investigated in conditions similar to those found in conventional hydraulic systems. The study shows that flat plate exhibit good force transmission for low pressure applications with a constant rate across frequencies, while exhibiting a decrease in force transmission at higher pressures. On the other hand the piston exhibit a more robust pressure design, with a constant force transmission rate at all pressures but with a dampening of force at higher frequencies. It is shown that small differences in force transmission ratios can have a considerable impact on the power generation.

  • 97.
    Aranda, Jesus Javier Lechuga
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bader, Sebastian
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fluid coupling interfaces for hydraulic pressure energy harvesters2017In: 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), IEEE, 2017, p. 1556-1562, article id 8014240Conference paper (Refereed)
    Abstract [en]

    The need for wireless sensor networks that can run for long times without the need of battery replacement has risen the need for energy harvesters. Industrial environments have plenty of energy sources that can be harvested; pressure fluctuations are a high energy density source that can be harvested using piezoelectric devices. Present devices have introduced flat metallic plates as the main force transmission elements for hydraulic fluctuations energy harvesters. In this paper, we analyze the force transmission efficiency of flat plates when used as the primary fluid coupling interface in hydraulic energy harvesters. Previous work has been focused on the optimization of circuit matching and pressure ripple amplification. In this work, we offer a look into the efficiencies of flat plates in different configurations and pressure loads. The analysis shows that despite the reasonable force transmission efficiency of flat plates in low-pressure environments, the overall efficiency of hydraulic energy harvesters can be improved if instead of flat plates, conventional hydraulic actuators, such as piston cylinders, could be used. 

  • 98.
    Arvidsson, Bertil
    et al.
    Fiberson AB.
    Jason, Johan
    Fiberson AB.
    Alexandersson, Robert
    Ericsson AB.
    Aspects of OTDR Measurements in a Cable Factory2009In: 9th OFMC Conference Digest, 2009, p. 113-117Conference paper (Other academic)
    Abstract [en]

    We will present OTDR-use in an optical cable factory with different types of applications. Doing this we will also present important instrument features and properties in an objective approach. The main reason for this work is to find a simplified use of the OTDR as regards to calibration and attenuation described in IEC 61746. One additional tool, which supports the approach, is to perform random round robin measurements between the fibre supplier and the cable factory.  Therefore, the two relevant topics will be: length calibration and attenuation measurement accuracy. In addition length accuracy will be discussed. This will then be followed by conclusions, which can be summarized as follows: The simplified OTDR-technique is well suited for use in a cable factory and in doing so both time and cost will be saved.

  • 99.
    Aryefyev, Maksym
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    NAT traversal techniques for MediaSense open source platform2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis project concerns NAT traversal techniques and their application to P2P networking with regard to MediaSense platform. Since MediaSense open source platform, developed by Mid Sweden University, utilizes the benefits of P2P networking, it also suffers from the drawbacks provided by NAT. The issue of NAT traversal is not trivial due to the fact that the behavior of NAT devices is not standardized and vendors are free to provide their own implementations. The common knowledge is, that at least four main types of NATs exist, differing in the filtering and mapping algorithms employed. NAT traversal techniques vary accordingly. No single technique can handle all the cases. Most of the techniques can handle up to three main types of NAT. The last type is usually used in large corporate networks and is called the Symmetric NAT. The most viable, and basically the only available technique for its traversal, is data relaying. This thesis builds a NAT traversal module for the MediaSense platform. The main purpose of this module is to provide seamless NAT traversal capabilities to the platform. The module does this in several steps: UPnP enabled device discovery, NAT type determination and data relaying via the proxy. Firstly the module attempts to discover the presence of a UPnP enabled Internet Gateway Device on the network. If such a device is present on the network, a port mapping can be created, making the node located behind NAT accessible from the public Internet. If a UPnP enabled device was not found, the module will try to determine the type of NAT used. Based on the type of NAT used, the module can transit to either the proxy mode or request assistance of the STUN server to keep the created mapping alive. The resulting chapters provide the reader with the output produced by each step, conclusions the author has made while working on this project and some general ideas on future work within the subject.

  • 100.
    Ascorti, Leonardo
    et al.
    Pepperl+Fuchs, Sulbiate, Italy.
    Savazzi, Stefano
    Institute of Electronics, Computer and Telecommunication Engineering, Milano, Italy.
    Soatti, Gloria
    Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy.
    Nicoli, Monica
    Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy.
    Sisinni, Emiliano
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. University of Brescia, Brescia, Italy.
    Galimberti, Stefano
    Pepperl+Fuchs, Sulbiate, Italy.
    A Wireless Cloud Network Platform for Industrial Process Automation: Critical Data Publishing and Distributed Sensing2017In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 66, no 4, p. 592-603, article id 7851047Article in journal (Refereed)
    Abstract [en]

    Wireless technologies combined with advanced computing are changing industrial communications. Industrial wireless networks can improve the monitoring and the control of the entire system by jointly exploiting massively interacting communication and distributed computing paradigms. In this paper, we develop a wireless cloud platform for supporting critical data publishing and distributed sensing of the surrounding environment. The cloud system is designed as a self-contained network that interacts with devices exploiting the time synchronized channel hopping protocol (TSCH), supported by WirelessHART (IEC 62591). The cloud platform augments industry-standard networking functions as it handles the delivery (or publishing) of latency and throughput-critical data by implementing a cooperative-multihop forwarding scheme. In addition, it supports distributed sensing functions through consensus-based algorithms. Experimental activities are presented to show the feasibility of the approach in two real industrial plant sites representative of typical indoor and outdoor environments. Validation of cooperative forwarding schemes shows substantial improvements compared with standard industrial solutions. Distributed sensing functions are developed to enable the autonomous identification of recurring cochannel interference patterns.

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