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  • 201.
    Asproth, Viveca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Ring, Andreas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Simulation of accessibility in Crisis Management2011Ingår i: CASYS'11: Tenth International Conference on Computing Anticipatory Systems / [ed] Daniel M. Dubois, Liége: CHAOS , 2011Konferensbidrag (Refereegranskat)
  • 202.
    Asproth, Viveca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Ring, Andreas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Borglund, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Accessibility in Crisis Management2011Ingår i: European Sociological Association Research Network 22 Sociology of Risk and Uncertainty RISK, UNCERTAINTY AND POLICY Midterm Conference 2011: Abstract book, 2011Konferensbidrag (Refereegranskat)
  • 203. Aubry-Fortuna, V.
    et al.
    Perrossier, J.L.
    Mamor, M.
    Meyer, F.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bodnar, S.
    Regolini, J.L.
    What is the role of the metal on the Fermi-level position at the interface with IV-IV compounds?1997Ingår i: Microelectronic Engineering, ISSN 0167-9317, Vol. 37/38, nr 1, s. 573-579Artikel i tidskrift (Refereegranskat)
  • 204. Aunet, S.
    et al.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Abdalla, Suliman
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Berg, Y.
    Reconfigurable Subthreshold CMOS Perceptron2004Ingår i: IEEE International Joint Conference on Neural Networks 2004, 2004Konferensbidrag (Refereegranskat)
  • 205. Aunet, Snorre
    et al.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    200 mV Full Adder Based on a Reconfigurable CMOS Perceptron2004Ingår i: Proceedings of IEEE International Conference on Signals and Electronic Systems, 2004Konferensbidrag (Refereegranskat)
  • 206. Aunet, Snorre
    et al.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Lande, Tor-Sverre
    Yngvar, Berg
    Multifunction Subthreshold Gate used for a Low Power Full Adder2004Ingår i: Proceedings of the IEEE Norchip Conference, 2004Konferensbidrag (Refereegranskat)
  • 207. Aunet, Snorre
    et al.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Norseng, Per Andreas
    Berg, Yngvar
    Real-time reconfigurable subthreshold CMOS perceptron2008Ingår i: IEEE Transactions on Neural Networks, ISSN 1045-9227, E-ISSN 1941-0093, Vol. 19, nr 4, s. 645-657Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a new, real-time reconfigurable perceptron circuit element is presented. A six-transistor version used as a threshold gate, having a fan-in of three, producing adequate outputs for threshold of T = 1, 2 and 3 is demonstrated by chip measurements. Subthreshold operation for supply voltages in the range of 100-350 mV is shown. The circuit performs competitively with a standard static complimentary metal-oxide-semiconductor (CMOS) implementation when maximum speed and energy delay product are taken into account, when used in a ring oscillator. Functionality per transistor is, to our knowledge, the highest reported for a variety of comparable circuits not based on floating gate techniques. Statistical simulations predict probabilities for making working circuits under mismatch and process variations. The simulations, in 120-nm CMOS, also support discussions regarding lower limits to supply voltage and redundancy. A brief discussion on bow the circuit may be exploited as a basic building block for future defect tolerant mixed signal circuits, as well as neural networks, exploiting redundancy, is included.

     

  • 208.
    Auzel, Francois
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    A condition in Ln-doped materials for flat optical gain2007Ingår i: Spectroscopy Letters, ISSN 0038-7010, E-ISSN 1532-2289, Vol. 40, nr 2, s. 197-207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fundamental conditions that rule gain flatness in Er-doped glass optical amplifiers are investigated using few parameters obtained by drastic simplifications for level positions and widths. The obtained general gain flatness condition for rare-earth-doped glasses contains two parts: a general one valid in any material and a slight modulation of it valid only for glasses when "0-0" transitions are involved. Essentially, the electron-phonon coupling for the considered materials has to be larger than 2/3. In order to exemplify these conditions, they are calculated for fluoride and silicate glasses, which are known to display respectively flat and non-flat gain behavior.

  • 209.
    Auzel, Francois
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Balda, R.
    Universidad del Pais Vasco, Bilbao, Spain.
    Fernadez, J.
    Universidad del Pais Vasco, Bilbao, Spain.
    Homogeneous line width of rare-earth-doped glasses for levels in a Stark level ladder: A new simple rule2007Ingår i: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 122, nr 1-2, s. 453-455Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Concentrating on higher Stark states in multiplet ladders of lanthanide-doped glasses, we show that at 10 K, the homogeneous widths along Stark ladders vary quasi-linearly with the energy position in the ladder.

    Assuming that the mechanisms creating the homogeneous widths are first-order processes, either direct processes or two-phonon nonradiative transitions, the observed behavior is simply explained by the fact that energy separations between Stark levels for usual glasses are less, i.e., not far from kT(D), the Debye energy. This in turn provides quasi-equal phonon transition probabilities between individual Stark states. A simple theoretical relationship is derived and compared with experiments.

  • 210.
    Auzel, Francois
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Baldacchini, Giuseppe
    ENEA, Department of Advanced Physical Technologies, Rome, Italy.
    Photon trapping in ruby and lanthanide-doped materials: Recollections and revival2007Ingår i: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 125, nr 1-2, s. 25-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    After some recollections of phonon and photon trapping in ruby, a critical review of this effect of renewed interest in trivalent lanthanide-doped materials is presented showing that the two independent derivations taking their roots in the work of Milne for gases and of Birks for organic scintillators are practically described by an analogous phenomenological equation when re-absorption is weak. The problem of obtaining "extrinsic" quantum efficiency larger than one is briefly discussed.

  • 211. Axelson, Lennart
    et al.
    Malmberg, Åke
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Expertsystem: En förstudie och en prototyp1991Rapport (Övrigt vetenskapligt)
  • 212.
    Axelsson, Anna Karin
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Scharpff, Jessica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    That´s the spirit we want in this company!: En kvalitativ studie om betydelsen av Kommunikativt Ledarskap för Employer Branding på Saab Group.2012Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Att attrahera topptalanger till sin organisation och skapa en trivsam och utmanande arbetsmiljö är något som har blivit allt viktigare. Den nya generationens medarbetare har helt andra prioriteringar när det kommer till att välja arbetsplats. Det handlar inte längre om vad den arbetssökande har att erbjuda organisationen, utan snarare tvärtom ställer sig många frågan, vad har organisationen att erbjuda mig?

    För att möta dessa behov måste organisationerna se till att ha en strategi för att attrahera och behålla medarbetarna. Strategin om Employer Branding handlar om att skapa ett starkt varumärke som arbetsgivare och se till att organisationen blir attraktiv och drar till sig medarbetare med rätt kompetens. Vår studie kommer att diskutera hur det kommunikativa ledarskapet kan underlätta i arbetet med Employer Branding.

    Vi har genomfört vår studie hos Saab Group och har använt oss av en kvalitativ metod för att söka svar på vårt syfte.

    Syftet med vår studie är att undersöka betydelsen av chefernas kommunikation på Saab Group och om en tillämpning av ett kommunikativt ledarskap kan stärka deras Employer Brand.

    Här följer de tre frågeställningar som vi har haft som utgångspunkt genomgående i studien.

    • • •

    Vad tycker Saabs medarbetare är viktigast i vad som utgör ett bra ledarskap? Hur kan chefernas kommunikation påverka trivseln på arbetsplatsen?

    På vilket sätt är kommunikativt ledarskap en viktig byggsten i ett starkt Employer Brand?

    Vi inledde studien med att intervjua Saab Groups internkommunikationschef och Employer Brandingchef i syfte att skapa oss en uppfattning om hur företaget arbetar med kommunikation, ledarskap och Employer Branding i dagsläget. Vidare genomförde vi fokusgrupper med totalt 20 medarbetare från tre olika affärsområden inom Saab Group.

    Resultatet av vår studie visar att ledarskapet är oerhört viktigt för hela uppfattningen om Saab Group. Det visar sig att det kommunikativa ledarskapet står för vad respondenterna anser är tillfredställande kommunikation, vilket gör att de trivs och känner sig trygga på arbetet. Resultatet har även visat att ledarna är totalt avgörande i utfallet med Employer Branding då de ska sätta ramverket och ta hänsyn till alla de viktiga delar som utgör ett starkt Employer Brand. Vår studie föreslår att genom en tillämpning av kommunikativt ledarskap kan Saab Group stärka sitt Employer Brand.

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  • 213.
    Axling, Ida
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Skog, Mikaela
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Digitala citat: Hur sociala medier används i dagstidningar2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Teknikens utveckling utgör en stor del av mediernas framåtskridande. Ny teknik möjliggör nya arbetssätt. Framväxten av internet har inneburit nya möjligheter för människor att socialisera med varandra. Sociala medier, som bloggar och Facebook, har också lett till nya förutsättningar för att sprida och hitta information.

    Att journalister har börjat använda sociala medier som källor i nyhetsrapporteringen innebär en förändring i hur källor värderas. Eftersom vem som helst har tillgång till sociala medier kan användandet av dem missbrukas, vilket gör det svårt att veta vem som egentligen ligger bakom informationen, något som är viktigt för nyhetsrapporteringens trovärdighet.

    Syftet med den här studien var att undersöka hur sociala medier används som källor i Sveriges fyra rikstäckande morgon- och kvällstidningar; Dagens Nyheter, Svenska Dagbladet, Aftonbladet och Expressen. Den syftade också till att ta reda på hur vanligt förekommande det är, vilket socialt medie som syns mest i tidningarna, vilken status källan har och vilken typ av nyheter dessa källor används till.

    För att besvara frågeställningarna gjordes en kvantitativ innehållsanalys. Under 14 dagar räknades antalet artiklar som innehöll sociala medier som källor och jämfördes med antalet artiklar som inte gjorde det. Undersökningen hade också kvalitativa inslag. För varje artikel där sociala medier använts, har ett antal frågor besvarats för att kartlägga hur källorna presenterades.

    Resultatet av undersökningen visar att sociala medier används som källor oftare i kvällstidningarna än i morgontidningarna, men att det förekommer i alla de fyra undersökta tidningarna. Politiker och anonyma källor citeras mest frekvent. Det vanligaste sociala mediet är bloggar, följt av Facebook.

    Gemensamt för alla fyra tidningarna är att sociala medier oftast återfinns i nyhetsdelen. De förekommer även som källor i kultur- och nöjesnyheterna, men under undersökningsperioden hittades sådana källor inte i sporten. I ungefär hälften av fallen kompletterades informationen från sociala medier med andra typer av källor. Lika ofta fanns källan med på bild i anslutning till artikeln.

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  • 214.
    Axroth, Maria
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Sedin, Malin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Före och efter monopolet: En studie om Apotekets strategiska kommunikationföre och efter monopolavregleringen2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Sedan Sverige gick med i EU har landets konkurrenspolitik blivit allt mer betydande.Konkurrens ökar tillväxten och kostnadseffektiviteten vilket främjar konsumenterna.Flertalet marknader i Sverige har monopolavreglerats, så som inrikesflyg-, el-,järnvägs-, post- och telekommunikationsmarknaden. År 2006 bestämde den svenskaregeringen att även avreglera apoteksmonopolet och sedan första juli år 2009 råder detkonkurrens på apoteksmarknaden. På en marknad i konkurrens måste organisationerarbeta annorlunda med sin strategiska kommunikation och syftet med denna studie äratt undersöka hur Apotekets kommunikativa strategier har påverkats dåorganisationen har gått från en monopolsituation till konkurrens.

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  • 215.
    Badel, X
    et al.
    KTH.
    Galeckas, A
    Linnros, Jan
    KTH.
    Kleimann, Pascal
    KTH.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Petersson, Sture
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Improvement of an X-ray imaging detector based on a scintillating guides screen2002Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 487, nr 1-2, s. 129-135Artikel i tidskrift (Refereegranskat)
  • 216. Badel, X.
    et al.
    Linnros, J.
    Kleimann, P.
    Norlin, Börje
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Koskiahde, E.
    Valpas, K.
    Nenonen, S.
    Petersson, Sture
    Department of Microelectronics, Roy. Inst. of Technology of Sweden, Kista.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Metallized and Oxidized Silicon Macropore Arrays Filled with a Scintillator for CCD-based X-ray Imaging Detectors2004Ingår i: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 51, nr 3 Part 3, s. 1001-1005Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silicon Charge Coupled Devices (CCD)covered with a scintillating film are now available on the market for use in digital medical imaging. However, these devices could still be improved in terms of sensitivity and especially spatial resolution by coating the CCD with an array of scintillating waveguides. In this work, we fabricated such waveguides by first etching pores in silicon, then performing metallization or oxidation of the pore walls and finally filling the pores with CsI(Tl). The resulting structures were observed using SEM and tested under X-ray exposure. The detector performances were also compared with simulations, indicating that the optimal pore depth for metallized macropore arrays is about 80 um while it is around 350 um for oxidized ones. This result, together with the roughness of the metal coating, explains why lower performances were measured experimentally with the metallized macropores. Indeed, our macropore arrays had depths in the range of 210-390 um, which is favorable to oxidized structures.

  • 217.
    Badel, X
    et al.
    KTH.
    Norlin, Börje
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Kleimann, P
    Université Claude Bernard Lyon-I, France.
    Williams, L
    Applied Scintillation Technology, United Kingdom.
    Moody, S.J.
    Applied Scintillation Technology, United Kingdom.
    Tyrrell, G.C.
    Applied Scintillation Technology, United Kingdom.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Linnros, J
    KTH.
    Performance of Scintillating Waveguides for CCD-based X-ray Detectors2006Ingår i: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 53, nr 1, s. 3-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Scintillating films are usually used to improve the sensitivity of CCD-based X-ray imaging detectors. For an optimal spatial resolution and detection efficiency, a tradeoff has to be made on the film thickness. However, these scintillating layers can also be structured to provide a pixellated screen. In this paper, the study of CsI(Tl)-filled pore arrays is reported. The pores are first etched in silicon, then oxidized and finally filled with CsI(Tl) to form scintillating waveguides. The dependence of the detector sensitivity on pore depth, varied from 40 to 400 µm here, follows rather well theoretical predictions. Most of the detectors produced in this work have a detective quantum efficiency of the incoming X-ray photons of about 25%; however, one detector shows that higher efficiency can be achieved. The comparison of its efficiency to a 1-mm thick CsI(Tl) crystal indicates that light collection efficiency in the guides may approach what is theoretically possible. Imaging capabilities of the detectors are demonstrated.

  • 218.
    Bader, Sebastian
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Enabling autonomous envionmental measurement systems with low-power wireless sensor networks2011Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Wireless Sensor Networks appear as a technology, which provides the basisfor a broad field of applications, drawing interest in various areas. On theone hand, they appear to allow the next step in computer networks, buildinglarge collections of simple objects, exchanging information with respect totheir environment or their own state. On the other hand, their ability tosense and communicate without a fixed physical infrastructure makes theman attractive technology to be used for measurement systems.Although the interest inWireless Sensor Network research is increasing,and new concepts and applications are being demonstrated, several fundamentalissues remain unsolved. While many of these issues do not requireto be solved for proof-of-concept designs, they are important issues to beaddressed when referring to the long-term operation of these systems. Oneof these issues is the system’s lifetime, which relates to the lifetime of thenodes, upon which the system is composed.This thesis focuses on node lifetime extension based on energy management.While some constraints and results might hold true from a moregeneral perspective, the main application target involves environmental measurementsystems based onWireless Sensor Networks. Lifetime extensionpossibilities, which are the result of application characteristics, by (i) reducingenergy consumption and (ii) utilizing energy harvesting are to be presented.For energy consumption, we show howprecise task scheduling due to nodesynchronization, combined with methods such as duty cycling and powerdomains, can optimize the overall energy use. With reference to the energysupply, the focus lies on solar-based solutions with special attentionplaced on their feasibility at locations with limited solar radiation. Furtherdimensioning of these systems is addressed.It will be shown, that for the presented application scenarios, near-perpetualnode lifetime can be obtained. This is achieved by focusing on efficient resourceusage and by means of a carefully designed energy supply.

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    Bader_Enabling autonomous envionmental measurement systems with low-power wireless sensor networks_2011
  • 219.
    Bader, Sebastian
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Anneken, Mathias
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Goldbeck, Manuel
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    SAQnet: Experiences from the Design of an Air Pollution Monitoring System Based on Off-the-Shelf Equipment2011Ingår i: Proceedings of the 2011 7th International Conference on Intelligent Sensors, Sensor Networks and Information Processing, ISSNIP 2011, IEEE conference proceedings, 2011, s. 223-228Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nowadays, air pollution is monitored with accurate, but large-sized measurement stations, leading to an overall limited number of monitored locations. Combining these stations, with a higher number of less accurate stations can provide additional information, such as with regards to pollutant distributions. In this paper we present the design, implementation and initial results of such stations based on Wireless Sensor Network technology. For the implementation of the network purely off-the-shelf equipment was chosen, which allows us to analyze the current status of commercially available Wireless Sensor Network technology. While the system was fully implemented and demonstrated operationally, the experiences found during the project showed a limited matureness with regards to the off-the-shelf equipment and uncovered flaws in typical assumptions underlying Wireless Sensor Network research. © 2011 IEEE.

  • 220.
    Bader, Sebastian
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Adaptive synchronization for duty-cycling in environmental wireless sensor networks2009Ingår i: ISSNIP 2009 - Proceedings of 2009 5th International Conference on Intelligent Sensors, Sensor Networks and Information Processing, IEEE conference proceedings, 2009, s. 49-54Konferensbidrag (Refereegranskat)
    Abstract [en]

    In wireless sensor networks, as energy limited systems, communication is a costly activity. For this reason duty cycling approaches are commonly used, because they can limit the overall power consumption of a sensor node tremendously by shutting down communication sub-circuits whenever they are not used. However, for efficient power reduction nodes have to know the exact times when they are supposed to communicate in the network. Synchronization can be used to accomplish this and comes with additional features such as the possibility of cooperative sampling at a given time. In this paper we propose a synchronization protocol that introduces low overhead due to broadcast master-node synchronization, while still accomplishing synchronization accuracies in the order of 100 μs. The protocol is intended for periodic data collection applications that are common tasks in environmental monitoring systems. Since changes in environmental conditions can have a large effect on the synchronization behavior, we further present a temperature compensation algorithm for the proposed synchronization protocol that allows stable usage of synchronization in a wide range of temperatures. Measurement results are taken from implementing the protocol on sensor node platforms and show the real world performance of the presented methods.

  • 221.
    Bader, Sebastian
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Durable Solar Energy Harvesting from Limited Ambient Energy Income2011Ingår i: International Journal on Advances in Networks and Services, ISSN 1942-2644, Vol. 4, nr 1&2, s. 66-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Typical wireless sensor network applications inthe domain of environmental monitoring require or profitfrom extended system lifetime. However, restrictions in sensornode resources, especially due to the usage of capacity limitedbatteries, forbid these desired lifetimes to be reached. Asopposed to batteries, energy harvesting from ambient energysources enables for near-perpetual supply of sensor nodes, asthe utilized energy source is inexhaustible. Nevertheless, thesupply from ambient energy sources is rate-limited, whereinthis supply-rate is mainly defined by the system deploymentlocation. On the other hand, the attached sensor node hasa consumption-rate, which has to be supplied to guaranteecontinuous node operation. In this paper, we address thematching of supply-rate and consumption-rate in solar energyharvesting systems at locations with limited insolation. Thefocus lies on the reduction of harvester energy overhead, whichin low-duty cycled system easily reaches similar or higherconsumption levels than the load it supplies. We suggest andpresent two harvester architectures [1], that have their maindesign consideration on simplicity. The individual modulesof the architectures are tested and verified in laboratorymeasurements and we evaluate the fully implemented systemsin an outdoor deployment. Based on the laboratory results,implementation choices for the architecture modules have beenmade. Whereas both harvesting architectures continuouslysupplied the attached load during the deployment period, wewere able to compare their behavior with each other andpresent individual advantages and drawbacks

  • 222.
    Bader, Sebastian
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Enabling battery-less wireless sensor operation using solar energy harvesting at locations with limited solar radiation2010Ingår i: Proceedings - 4th International Conference on Sensor Technologies and Applications, SENSORCOMM 2010, IEEE conference proceedings, 2010, s. 602-608Konferensbidrag (Refereegranskat)
    Abstract [en]

    Environmental monitoring applications demand wireless sensor networks to operate over a long period of time. Although energy consumption of these systems has been tremendously reduced, lifetime of sensor nodes is still limited by the capacity and lifetime of batteries used as energy sources. Energy harvesting, and in outdoor deployments particular, solar energy harvesting becomes a suitable way of powering wireless sensor nodes as their power consumption decreases. In this paper we address the feasibility of battery-less operation of wireless sensor nodes using solar energy harvesting at locations where the amount of solar radiation is severely limited and seasonal variations are large. We present two circuit architectures optimized for low energy leakage and evaluate their performance based on data gathered in a deployment during winter in Sundsvall, Sweden. We show that both architectures allow operation of sensor nodes even in the darkest period of the year. Furthermore comparisons between the two architecture designs are provided. © 2010 IEEE.

  • 223.
    Bader, Sebastian
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Brunig, M.
    Autonomous Systems Laboratory, ICT Centre, CSIRO, Brisbane, Australia.
    Challenges for RF two-way time-of-flight ranging in wireless sensor networks2012Ingår i: Proceedings - Conference on Local Computer Networks, LCN, IEEE conference proceedings, 2012, s. 908-916Konferensbidrag (Refereegranskat)
    Abstract [en]

    In applications where a priori determination of location is infeasible, node localization schemes are desirable, which allow the node to estimate its location during network operation. The majority of these schemes are based on ranging between node pairs, which should ideally be performed without adding cost or size to the sensor node. Two-way time-of-flight schemes can fulfill this desire, by utilizing the measurement of the time-of-flight of electromagnetic waves to determine the distance between two sensor nodes. In this paper, we present the implementation and analysis of such a ranging scheme. Because a small error in time measurement can result in a large distance estimation error, the focus of this work lies on the determination and analysis of influencing factors, which limit the accuracy of round-trip-time measurements. We analyze two main contributing factors to the accuracy of the ranging scheme, namely the radio transceiver clock quantization and the link quality during round-trip-time measurement. These effects and their impact on the overall ranging error have been investigated by means of simulation and experimentation. Initial ranging errors as large as 24 m RMS were observed, which could be reduced to errors between 5 and 8 m RMS by utilizing compensation techniques.

  • 224.
    Bader, Sebastian
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Schölzel, Torsten
    Solar Watt AG, Germany.
    Oelmann, Bengt
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    A Method for Dimensioning Micro-Scale Solar Energy HarvestingSystems Based on Energy Level Simulations2010Ingår i: Proceedings - IEEE/IFIP International Conference on Embedded and Ubiquitous Computing, EUC 2010, IEEE conference proceedings, 2010, s. 372-379Konferensbidrag (Refereegranskat)
    Abstract [en]

    Solar energy harvesting gains more and more attention in the field of wireless sensor networks. In situations, where these sensor systems are deployed outdoors, powering sensor nodes by solar energy becomes a suitable alternative to the traditional way of battery power supplies. Since solar energy, opposed to batteries, can be considered as an inexhaustible energy source, scavenging this source allows longer system lifetimes and brings wireless sensor networks closer to be an autonomous system with perpetual lifetime. Despite the possibility of designing and constructing these harvesting system, dimensioning becomes a crucial task to fit implemented components to application and load system demands. In this paper we present a way of dimensioning solar harvesting systems based on simulation. Method and implementation of component and system models are described on the basis of an example architecture that has been used in prior work. Furthermore we evaluate the model in comparison to deployment of the same architecture and show the suitability of using the simulation as a support to optimize choices for system parameters

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  • 225. Bakowski, M
    et al.
    Gustafsson, U
    Lindefelt, Ulf
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Simulation of SiC high power devices1997Ingår i: Physica Status Solidi A, ISSN 0031-8965, Vol. 162, nr 1, s. 421-440Artikel i tidskrift (Refereegranskat)
  • 226. Ballabriga, R.
    et al.
    Blaj, G.
    Campbell, M.
    Fiederle, M.
    Greiffenberg, D.
    Heijne, E. H. M.
    Llopart, X.
    Plackett, R.
    Procz, S.
    Tlustos, L.
    Turecek, D.
    Wong, Winnie
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Characterization of the Medipix3 pixel readout chip2011Ingår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 6, nr 1Artikel i tidskrift (Refereegranskat)
  • 227. Ballabriga, R
    et al.
    Campbell, M
    Heijne, E H M
    Llopart Cudié, Xavier
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Tlustos, L
    The Medipix3 prototype, a pixel readout chip working in single photon counting mode with improved spectrometric performance2006Ingår i: procedings of Nuclear Science Symposium IEEE 2006, Ocotber 2006, San Diego USA, 2006Konferensbidrag (Refereegranskat)
  • 228. Ballabriga, R.
    et al.
    Campbell, M.
    Heijne, E.
    Llopart, X.
    Tlustos, L.
    Wong, Winnie
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Medipix3: A 64 k pixel detector readout chip working in single photon counting mode with improved spectrometric performance2011Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 633, nr SUPPL. 1, s. S15-S18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Medipix3 is a 256×256 channel hybrid pixel detector readout chip working in a single photon counting mode with a new inter-pixel architecture, which aims to improve the energy resolution in pixelated detectors by mitigating the effects of charge sharing between channels. Charges are summed in all 2×2 pixel clusters on the chip and a given hit is allocated locally to the pixel summing circuit with the biggest total charge on an event-by-event basis. Each pixel contains also two 12-bit binary counters with programmable depth and overflow control. The chip is configurable such that either the dimensions of each detector pixel match those of one readout pixel or detector pixels are four times greater in area than the readout pixels. In the latter case, event-by-event summing is still possible between the larger pixels. Each pixel has around 1600 transistors and the analog static power consumption is below 15 μW in the charge summing mode and 9 μW in the single pixel mode. The chip has been built in an 8-metal 0.13 μm CMOS technology. This paper describes the chip from the pixel to the periphery and first electrical results are summarized.

  • 229.
    Banck, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nyström, Christina Amcoff
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Free the User and Liberate the Designer2001Ingår i: IRIS 24: proceedings of the 24th Information Systems Research Seminar in Scandinavia : Ulvik, Norway, 11-14 August 2001, Bergen: University of Bergen , 2001, s. 693-710Konferensbidrag (Refereegranskat)
    Abstract [en]

    The authors have chosen to apply different aspects of design to a model for a first (preparatory) design of information systems. We will describe important aspects and standpoints, and suggest a first model including a Meta method and a virtual toolbox. Initially we focus on the identification of suitable criteria for a general design of systems development, aspects of design for the first model (starting point model) and the early steps/phases in the development of information systems. We also briefly discuss the model and the Meta method on Intranet in terms of further development.

  • 230.
    Banck, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nyström, Christina Amcoff
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Intranet - a tool for power and control or a possibility to increase the quality of work2002Ingår i: Promote IT 2002: Second Conference for the Promotion of Research in IT at New Universities and University Colleges in Sweden 22-24 April, 2002 Billingehus, Skövde Sweden, 2002, s. 223-234Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we briefly present research related to Intranets in order to define topics of interest. The presented research mainly focuses on: intranet implementation, initiative, stakeholders, roles, and other organizational questions. We also present an umbrella project – VICQ (Viable Intranet for Creativity and Quality), related to the research in progress. This umbrella project intends to focus on questions concerning the use of intranets, philosophy of mangers, philosophy of technology, aspects of design. Some future part projects are identified and described as well as a planned pilot study. In the pilot study we will investigate a number of intranets. The result will be an analysis and a description of three different groups (managers, IS-services, users) view of their intranet. We shall use this analyze to specify questions for further work.

  • 231.
    Banck, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nyström, Christina Amcoff
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Intranet - Ongoing Research and Future Directions2005Ingår i: Advances in Applied Systems Research: Vol. I: Cognitive Models/Intranet/ 3D Object Retrieval/Steganographic Applications/ E-Commerce, Ontario, Canada: IIAS , 2005, s. 9-18Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    In this paper we briefly present ongoing research related to Intranets in order to define shortcomings and needs for further research. An Intranet often mirrors the organization’s and the managers’ view of employees. An Intranet is more a tool to support the organization in common than to solve separate tasks. We outline the ‘map of the world of research of intranets’ where knowledge management, organization theory, design and informatics are the main cornerstones that overlap each other. There are different kinds of approaches depending on the Intranet researchers’ choice of problem domain. One approach is Intranet development in a broad sense as the problem domain. Other researchers have knowledge management as the problem domain and consider Intranet as one way to handle KM. Researchers, who have chosen Intranet as the secondary problem domain, might have their theoretical starting points in other disciplines/spheres of interest. Examples of these disciplines might be organization theory, social science and knowledge. Ongoing research on Intranet mainly focuses on different aspects of implementation, initiative, development processes, knowledge management and roles. There are lacks due to the number of empirical studies. The use of Intranets is poorly investigated and questions about aspects that influence the understanding and use of an Intranet are being raised.

  • 232.
    Banck, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nyström, Christina Amcoff
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Intranet Use: A Study in Five Swedish Organisations2003Ingår i: Promote IT 2003: 5-7 may,2003, Gotland University, Sweden, Visby: Gotland University , 2003Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a study of intranet in five Swedish organisations The purpose with the study was to investigate in what way different aspects influences the use and understanding of intranet. The method used was an explorative approach, based on two interview guides. The first interview guide was directed to managers and IS representatives, dealt with background aspects of the intranets as well as data about the businesses and their intranets. The second interview guide directed to all kind of users covered aspects about use of intranet and in what way users could influence the content of intranet and the understanding of intranet. The persons interviewed represented end-users, managers and members of the IS-staffs. The interviews were carried out from May to November 2002. The results showed that the intranets in the study were poor matured and the main use mode was publishing. The underlying philosophy of the intranets seemed to be more that the users were informing themselves instead of inform others Furthermore, the use and understanding of intranet differed between end-users vs. managers and the IS-staff. Finally, we have identified important aspects to be considered when investigating use of intranets in further research. These aspects are strategies, context, further development process, competence, and the intranets belonging to the organisation as well as the culture of the organisation.

  • 233.
    Banck, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nyström, Christina Amcoff
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Intranet Use: A Study of Five Swedish Organizations2005Ingår i: Journal of Organizational Transformation and Social Change, ISSN 1477-9633, Vol. 2, nr 2, s. 153-180Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a study carried out 2002, concerning the Intranet in five Swedish organizations. The purpose is to investigate in what way different aspects influence the use and understanding of an Intranet. An explorative approach is used, based on two interview guides. The first guide is aimed at managers and IS representatives and covers background aspects of the Intranets, as well as data about the businesses and their Intranets. The second guide is directed to all kinds of users and covers aspects of the use of Intranet and in what way users can influence the content and understanding of the Intranet. The persons interviewed represent end-users, managers and members of the IS staff. Results show that the Intranets in the study are poorly matured and that the main use mode is ‘publishing’. The underlying philosophy of the Intranets seems to be self-information rather than informing others. Furthermore, the use and understanding of Intranet differs between end-users, managers and IS –staff, according to trust and ideas of responsibilities. Finally, important aspects to be considered when investigating the use of Intranets in further research are identified. These aspects are strategies, social context, further development process, competence and the Intranets’ organizational affiliation as well as the culture of the organization.

  • 234.
    Banck, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nyström, Christina Amcoff
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Intranätanvändning - en studie i fem svenska organisationer2003Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Syftet med den enskilda studien var: att inom VICQ-projektets ram, stärka kunskapen om den faktiska användningen av intranät (användningen förklarad via upplevelser av strategi och syfte, initiativ, införande, utveckling) och härvid särskilt belysa olika personalkategoriers uppfattning om intranätet, att utifrån resultatet av ovanstående, identifiera och precisera ytterligare frågeställningar relaterat till vår utgångspunkt (utgångsmodellen) inför kommande studier

  • 235.
    Bao, Zhixian
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Data acquisition of pressure and heart beat rate using TinyOS for e-health care application2012Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The objective of the presented report focuses on the data acquisition of pressure and heart beat rates from external sensors over the TinyOS 2.x platform. This sensing application may be used in the e-health care field in order to sample the data information. The designed test-bed consists of several hardware devices, containing an MIB520CB USB interface board, two MICAz motes, an MDA300CA data acquisition board and external sensors for the pressure and heart beat rate. The programming language is NesC,which is used to build applications under the TinyOS 2.x environment. Data information is sampled from the external sensors, and this is then realized by the mote via the on-board ADC channel. The values are then transferred from one mote to another over radio communication. Finally, the expected results are transmitted to the PC by using serial communication. The report also discusses the sensing outcomes in order to determine the practical usage of the sensor devices. This project represents a common sensing application in wireless sensor networks, demonstrating a small case within the e-health care monitoring system. In order to meet the specific demands and to save resources, the wireless sensor networks are widely used in various applications. The designed test-bed could be also deployed as a part of larger-scale wireless sensor networks in order to achieve the requirements in relation to the sensing data information for further detailed use in future work.

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    fulltext
  • 236.
    Barac, Filip
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Gidlund, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier. ABB Corporate Research, Sweden.
    Åkerberg, Johan
    ABB Corporate Research, Sweden.
    A Lightweight Routing Protocol for Industrial Wireless Sensor and Actuator Networks2011Ingår i: Proceedings of IECON 2011 - 37th Annual Conference on IEEE Industrial Electronics Society, Melbourne, Australia: IEEE Industrial Electronics Society , 2011, s. 2980-2985Konferensbidrag (Refereegranskat)
    Abstract [en]

    The applications of Industrial Wireless Sensor and Actuator Networks (IWSAN) are time-critical and subject to strict requirements in terms of end-to-end delay and reliability of data delivery. A notable shortcoming of the existing wireless industrial communication standards is the existence of overcomplicated routing protocols, whose adequacy for the intended applications is questionable [1]. This paper evaluates the potentials of flooding as a data dissemination technique in IWSANs. The concept of flooding is recycled by introducing minimal modifications to its generic form and compared with a number of existing WSN protocols, in a variety of scenarios. The simulation results of all scenarios observed show that our lightweight approach is able to meet stringent performance requirements for networks of considerable sizes. Furthermore, it is shown that this solution significantly outperforms a number of conventional WSN routing protocols in all categories of interest.

  • 237.
    Barac, Filip
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Yu, Kan
    Mälardalen University College, Sweden.
    Gidlund, Mikael
    ABB AB, Corporate Research, Sweden.
    Åkerberg, Johan
    ABB AB, Corporate Research, Sweden.
    Björkman, Mats
    Mälardalen University College, Sweden.
    Towards Reliable and Lightweight Communication in Industrial Wireless Sensor Networks2012Ingår i: Procedings of the IEEE 10th International Conference on Industrial Informatics, INDIN 2012, IEEE conference proceedings, 2012, s. 1218-1224Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we address the issues of timeliness and transmission reliability of existing industrial communication standards. We combine a Forward Error Correction coding scheme on the Medium Access Control layer with a lightweight routing protocol to form an IEEE 802.15.4-conformable solution, which can be implemented into already existing hardware without violating the standard. After laying the theoretical foundations, we conduct a performance evaluation of the proposed solution. The results show a substantial gain in reliability and reduced latency, compared to the uncoded transmissions, as well as common Wireless Sensor Network routing protocols.

  • 238. Barbier, C.
    et al.
    Larsson, P. -L
    Östlund, S.
    Eklund, Johan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Folding of printed papers: Experiments and numerical analysis2003Konferensbidrag (Refereegranskat)
    Abstract [en]

    Folding of digital prints has been investigated experimentally in order to determine the influence from different features on the residual tensile strength of the folded paper. In particular, the effect of toner-layer, paper-fibre orientation and pre-creasing is investigated and the experimental results are supplemented with numerical ones based on the finite element method. The results indicate that creasing, and to a less extent also fibre orientation, is the most important factor influencing the residual tensile strength after folding.

  • 239. Barkowsky, M
    et al.
    Brunnström, Kjell
    Acreo ICT Swedish AB.
    Ebrahimi, T
    Karam, L
    Lebreton, P
    Le Callet, P
    Perkis, A
    Raake, A
    Subedar, M
    Wang, Kun
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Xing, L
    You, J
    Subjective and Objective Visual Quality Assessment in the Context of stereoscopic 3DTV2013Ingår i: 3DTV System with Depth-Image-Based Rendering / [ed] Yu, L., Tanimoto, M., and Zhu, C., Springer, 2013, s. 413-437Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Subjective and objective visual quality assessment in the context of stereoscopic three-dimensional TV (3D-TV) is still in the nascent stage and needs to consider the effect of the added depth dimension. As a matter of fact, quality assessment of 3D-TV cannot be considered as a trivial extension of two-dimensional (2D) cases. Furthermore, it may also introduce negative effects not experienced in 2D, e.g., discomfort or nausea. Based on efforts initiated within the cost action ICT 1003 QUALINET, this chapter discusses current challenges in relation to subjective and objective visual quality assessment for stereo-based 3D-TV. Two case studies are presented to illustrate the current state of the art and some of the remaining challenges. © Springer Science+Business Media New York 2013. All rights are reserved.

  • 240. Barkowsky, M.
    et al.
    Wang, Kun
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Cousseau, R.
    Brunnstrom, K.
    Olsson, Roger
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Le Callet, P.
    Subjective quality assessment of error concealment strategies for 3DTV in the presence of asymmetric transmission errors2010Ingår i: Proceedings of 2010 IEEE 18th International Packet Video Workshop (PV, 2010, s. 193-200Konferensbidrag (Refereegranskat)
    Abstract [en]

    The transmission of 3DTV sequences over packet based networks may result in degradations of the video quality due to packet loss. In the conventional 2D case, several different strategies are known for extrapolating the missing information and thus concealing the error. In 3D however, the residual error after concealment of one view might leads to binocular rivalry with the correctly received second view. In this paper, three simple alternatives are presented: frame freezing, a reduced playback speed, and displaying only a single view for both eyes, thus effectively switching to 2D presentation. In a subjective experiment the performance in terms of quality of experience of the three methods is evaluated for different packet loss scenarios. Error-free encoded videos at different bit rates have been included as anchor conditions. The subjective experiment method contains special precautions for measuring the Quality of Experience (QoE) for 3D content and also contains an indicator for visual discomfort. The results indicate that switching to 2D is currently the best choice but difficulties with visual discomfort should be expected even for this method.

  • 241.
    Barkowsky, Marcus
    et al.
    Université de Nantes, France.
    Tourancheau, Sylvain
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Brunnström, Kjell
    NetLab: IPTV, Video and Display Quality, Acreo AB, 16440 Kista, Sweden.
    Wang, Kun
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Andrén, Börje
    NetLab: IPTV, Video and Display Quality, Acreo AB, 16440 Kista, Sweden.
    Crosstalk Measurements of Shutter Glasses 3D Displays2011Ingår i: 49th Annual SID Symposium, Seminar, and Exhibition 2011, Display Week 2011, Wiley-Blackwell, 2011, s. 812-815Konferensbidrag (Refereegranskat)
    Abstract [en]

    Crosstalk is probably one of the main perceptual factors contributing to perceived image quality and visual comfort. The Video Quality Experts Group (VQEG) within their 3D video quality project is specifying a practical measurement procedure that will produce consistent results across laboratories. This paper is part of that effort. Two different method of measuring cross talk on shutter glasses stereo displays have been studied. One is based on time average luminance measurements and the other on temporal measurements. The results show that crosstalk is roughly 0.5% but that there are differences in the crosstalk between the two eyes in the shutter glasses.

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    Barkowsky2011_Crosstalk_Measurements_of_Shutter_Glasses_3D-Displays
  • 242. Becker, J.
    et al.
    Bianco, L.
    Gottlicher, P.
    Graafsma, Heinz
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Hirsemann, H.
    Jack, S.
    Klyuev, A.
    Marras, A.
    Trunk, U.
    Klanner, R.
    Schwandt, J.
    Zhang, J.
    Dinapoli, R.
    Greiffenberg, D.
    Henrich, B.
    Mozzanica, A.
    Schmitt, B.
    Shi, X.
    Gronewald, M.
    Kruger, H.
    Architecture and design of the AGIPD detector for the European XFEL2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    AGIPD is a hybrid pixel detector developed by DESY, PSI, the University of Bonn and the University of Hamburg. The detector is targeted for use at the European XFEL, a source with unique properties: a bunch train of 2700 pulses with > 1012 photons of 12 keV each, only 100 fs long and with a 220 ns spacing, is repeated at a 10Hz rate. This puts up very demanding requirements: dynamic range has to cover the detection of single photons and extend up to > 104 photons/pixel in the same image, and as many images, as possible have to be recorded in the pixel to be read out between pulse trains. The high photon flux impinging on the detector also calls for a very radiation hard design of sensor and ASIC. The detector will consist of 16 Sensor modules arranged around a central hole for the direct beam. Each made of a single sensor bump-bonded to 2 × 8 readout chips of 64 × 64 pixels in a grid of 200 μm pitch. Each pixel of these ASICs contains a charge sensitive preamplifier featuring adaptive gain switching, changing sensitivity in three ranges, and a buffer to provide correlated double sampling (in the highest sensitivity mode). Most of the pixel area, albeit, is used for an analogue memory to record 352 frames. It is operated in random-access mode: data containing bad frames can be overwritten and the memory can be used in the most efficient way. The readout between two bunch trains is arranged via 4 ports: Data from pixels of one row is read in parallel and serialised by 4 multiplexers at the end of the pixel columns and driven off-chip as differential signals. The operation of the ASIC is controlled via a three-line serial interface, using a command based protocol. It is also used to configure the chip's operational parameters and internal timings. © 2012 IEEE.

  • 243.
    Becker, J.
    et al.
    Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany.
    Pennicard, D.
    Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany.
    Graafsma, Heinz
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    The detector simulation toolkit HORUS2012Ingår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 7, nr 10, s. Art. no. C10009-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent years, X-ray detectors used and developed at synchrotron sources and Free Electron Lasers (FELs) have become increasing powerful and versatile. However, as the capabilities of modern X-ray cameras grew so did their complexity and therefore their response functions are far from trivial. Since understanding the detecting system and its behavior is vital for any physical experiment, the need for dedicated powerful simulation tools arose. The HPAD Output Response fUnction Simulator (HORUS) was originally developed to analyze the performance implications of certain design choices for the Adaptive Gain Integrating Pixel Detector (AGIPD) and over the years grew to a more universal detector simulation toolkit covering the relevant physics in the energy range from below 1 keV to a few hundred keV. HORUS has already been used to study possible improvements of the AGIPD for X-ray Photon Correlation Spectroscopy (XPCS) at the European XFEL and its performance at low beam energies. It is currently being used to study the optimum detector layout for Coherent Diffration Imaging (CDI) at the European XFEL. Simulations of the charge summing mode of the Medipix3 chip have been essential for the improvements of the charge summing mode in the Medipix3 RX chip. HORUS is universal enough to support arbitrary hybrid pixel detector systems (within limitations). To date, the following detector systems are predefined within HORUS: The AGIPD, the Large Pixel Detector (LPD), the Cornell-Stanford Pixel Array Detector (CSPAD), the Mixed-Mode (MMPAD) and KEKPAD, and the Medipix2, Medipix3 and Medipix3 RX chips. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

  • 244.
    Bejugam, Santosh
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Tremor quantification and parameter extraction2011Självständigt arbete på avancerad nivå (masterexamen), 80 poäng / 120 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Tremor is a neuro degenerative disease causing involuntary musclemovements in human limbs. There are many types of tremor that arecaused due to the damage of nerve cells that surrounds thalamus of thefront brain chamber. It is hard to distinguish or classify the tremors asthere are many reasons behind the formation of specific category, soevery tremor type is named behind its frequency type. Propermedication for the cure by physician is possible only when the disease isidentified.Because of the argument given in the above paragraph, there is a needof a device or a technique to analyze the tremor and for extracting theparameters associated with the signal. These extracted parameters canbe used to classify the tremor for onward identification of the disease.There are various diagnostic and treatment monitoring equipment areavailable for many neuromuscular diseases. This thesis is concernedwith the tremor analysis for the purpose of recognizing certain otherneurological disorders. A recording and analysis system for human’stremor is developed.The analysis was performed based on frequency and amplitudeparameters of the tremor. The Fast Fourier Transform (FFT) and higherorderspectra were used to extract frequency parameters (e.g., peakamplitude, fundamental frequency of tremor, etc). In order to diagnosesubjects’ condition, classification was implemented by statisticalsignificant tests (t‐test).

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  • 245. Bellotti, E
    et al.
    Farahmand, M
    Goano, M
    Ghilliano, E
    Garetto, C
    Ghione, G
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Brennan, K.F.
    Ruden, P.P.
    Simulation of carrier transport in wide band gap semiconductors2001Ingår i: International Journal of High Speed Electronics and Systems, ISSN 0129-1564, Vol. 11, nr 2, s. 525-584Artikel i tidskrift (Refereegranskat)
  • 246. Bellotti, E
    et al.
    Farahmand, M
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Brennan, KF
    Ruden, PP
    Shul, Randy J
    Monte Carlo based calculation of transport parameters for wide band gap device simulation2001Ingår i: Materials Research Society symposia proceedings, Warrendale: Materials Research Society , 2001, , s. T6241-T6246s. T6241-T6246Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present Monte Carlo based calculations of transport parameters useful in the simulation of III-nitride and SiC based devices. The calculations are performed using a full band ensemble Monte Carlo model that includes numerical formulations of the phonon scattering rates and impact ionization transition rates. Calculations are made for the wurtzite and zincblende phases of GaN, the wurtzite phase of InN, and the 3C (cubic) and 4H phases of SiC. The basic transport parameters determined are saturation drift velocity, and the ionization coefficients as a function of applied electric field. Results from the various materials are finally compared.

  • 247. Bellotti, E.
    et al.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Brennan, K.F.
    Ruden, P.P.
    Ensemble Monte Carlo calculation of hole transport in bulk 3C-SiC1999Ingår i: Journal of Applied Physics, ISSN 0021-8979, Vol. 85, nr 6, s. 3211-3217Artikel i tidskrift (Refereegranskat)
  • 248. Bellotti, E.
    et al.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Brennan, K.F.
    Ruden, P.P.
    Trew, R.
    Monte Carlo calculation of hole initiated impact ionization in 4H phase SiC2000Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 87, nr 8, s. 3864-3871Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article, we present a comprehensive, full band theoretical study of the high field, hole transport properties of the 4H phase of silicon carbide (4H-SiC). The calculations are performed using a full band ensemble Monte Carlo simulation that includes numerically tabulated impact ionization rates, and phonon and ionized impurity scattering rates. In addition, the simulation includes a mechanism, interband tunneling, by which the holes can move between bands in the proximity of band intersection points, It is found that there exists a significant anisotropy in the calculated steady-state hole drift velocity for fields applied parallel and perpendicular to the c-axis direction. Good agreement with experimental measurements of the hole initiated impact ionization coefficient for fields applied along the c axis is obtained, provided that interband tunneling in the proximity of band intersections is included in the model. If interband tunneling is not included, the calculated ionization coefficients are orders of magnitude lower than the experimental measurements. © 2000 American Institute of Physics.

  • 249.
    Bengone, Oliver
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Eriksson, O
    Fransson, J
    Turek, I
    Kudrnovsky, J
    Drchal, V
    Electronic structure and transport properties of CrAs/GaAs/CrAs trilayers from first principles theory2004Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 70, nr 3, s. 035302-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a theoretical study of the transport properties of a CrAs/GaAs/CrAs trilayer. The theory was based on a first principles method for calculating the electronic structure, in combination with a Kubo-Landauer approach for calculating the transport properties in a current perpendicular to the plane geometry. We have also investigated the electronic structure and the magnetic properties of this trilayer, with special focus on electronic and magnetic properties at the CrAs/GaAs interface. Finally, we have studied the effects of chemical disorder on the transport properties, in particular the influence of As antisites at both the Cr and Ga sites.

  • 250.
    Bengone, Oliver
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Eriksson, O
    Mirbt, S
    Turek, I
    Kudrnovsky, J
    Drchal, V
    Origin of the negative giant magnetoresistance effect in Co1-xCrx/Cu/Co (111) trilayers2004Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 69, nr 9, s. 092406-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a theoretical study on Co1-xCrx/Cu/Co (111) trilayers, where a transition from positive to negative giant magnetoresistance effect has been observed experimentally, with increasing thickness of the alloyed layer. The theory, based on a recently implemented conductance calculation, reproduces quantitatively this observation, and the effect is found to be caused by alloying effects, due to a virtual bound Cr d state in the majority spin channel of the Co-Cr layer.

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