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  • 251.
    Soleiman, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datorteknik.
    Battery-free Visible Light Sensing2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis, we show that it is possible to design a battery-free light sensing system that can sense and communicate hand gestures while operating fully on harvested power from indoor light. We present two main innovations that push our system to tens of microwatts of power to enable battery-free operation. First, we introduce a novel visible light sensing system that can track variations in light intensity by using a solar cell as a sensor. Solar cells are unlike photodiodes optimized for energy yield in the visible light region and hence do not require any power hungry active components such as an operational amplifier. Furthermore, solar cells can operate under more diverse light conditions as they are not susceptible to saturation under bright light. Second, we devise two ultra-low power communication mechanisms based on radio frequency backscatter to transmit sensor readings at various resolutions without the need of any energy-expensive computational blocks.  We design two battery-free and self-powered hardware prototypes that are based on these two innovations. Our first design utilizes an on-board comparator based circuit to perform a 1-bit digitization of changes in light readings, consuming only sub-microwatt of power for digitization. For our second prototype, we design an analog backscatter mechanism that can map raw sensor readings directly to backscatter transmissions. We demonstrate the feasibility of our designs when sensing significant changes in light intensity caused by shadows from hand gestures, and reconstruct these at a receiving device. Our results demonstrate the ability to sense and communicate various hand gestures at a peak power of 20 microwatts when performing 1-bit digitization, and a mean power of 60 microwatts when performing analog backscatter. Both designs represent orders of magnitude improvement in terms of power consumption over state-of-the-art visible light sensing systems.

    Fulltekst (pdf)
    fulltext
  • 252.
    Spiliopoulos, Vasileios
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Bagdia, Akash
    Hansson, Andreas
    Aldworth, Peter
    Kaxiras, Stefanos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Introducing DVFS-Management in a Full-System Simulator2013Inngår i: Proc. 21st International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, IEEE Computer Society, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Dynamic Voltage and Frequency Scaling (DVFS) is an essential part of controlling the power consumption of any computer system, ranging from mobile phones to servers. DVFS efficiency relies on hardware-software co-optimization, thus using existing hardware cannot reveal the full optimization potential beyond the current implementation’s characteristics. To explore the vast design space for DVFS efficiency, that straddles software and hardware, a simulation infrastructure must provide features that are not readily available today, for example: software controllable clock and voltage domains, support for the OS and the frequency scaling module of it, and an online power estimation methodology. As the main contribution,this work enables DVFS studies in a full-system simulator. We extend the gem5 simulator to support full-system DVFS modeling. By doing so, we enable energy-efficiency experiments to be performed in gem5 and we showcase such studies. Finally, we show that both existing and novel frequency governors for Linux and Android can be effortlessly integrated in the framework, and we evaluate the efficiency of different DVFS schemes.

  • 253.
    Spiliopoulos, Vasileios
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Sembrant, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Kaxiras, Stefanos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Power-Sleuth: A Tool for Investigating your Program's Power Behavior2012Inngår i: International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS'12), 2012, s. 241-250Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modern processors support aggressive power saving techniques to reduce energy consumption. However, traditional profiling techniques have mainly focused on performance, which does not accurately reflect the power behavior of applications. For example, the longest running function is not always the most energy-hungry function. Thus software developers cannot always take full advantage of these power-saving features.

    We present \powersleuth, a power/performance estimation tool which is able to provide a full description of an application's behavior for any frequency from a single profiling run. The tool combines three techniques: a power and a performance estimation model with a program phase detection technique to deliver accurate, per-phase, per-frequency analysis.

    Our evaluation (against real power measurements) shows that we can accurately predict power and performance across different frequencies with average errors of 3.5% and 3.9% respectively.

  • 254.
    Sun, Jinghao
    et al.
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China.;Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Guan, Nan
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Wang, Yang
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    He, Qingqiang
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Real-Time Scheduling and Analysis of OpenMP Task Systems with Tied Tasks2017Inngår i: 2017 IEEE Real-Time Systems Symposium (RTSS), IEEE, 2017, s. 92-103Konferansepaper (Fagfellevurdert)
    Abstract [en]

    OpenMP is a promising framework for developing parallel real-time software on multi-cores. Although similar to the DAG task model, OpenMP task systems are significantly more difficult to analyze due to constraints posed by the OpenMP specification. An important feature in OpenMP is tied tasks, which must execute on the same thread during the whole life cycle. Although tied tasks enjoy benefits in simplicity and efficiency, it was considered to be not suitable to real-time systems due to its complex behavior. In this paper, we study the real-time scheduling and analysis of OpenMP task systems with tied tasks. First, we show that under the existing scheduling algorithms in OpenMP, tied tasks indeed may lead to extremely bad timing behaviors where the parallel workload is sequentially executed completely. To solve this problem, we proposed a new scheduling algorithm and developed two response time bounds for it, with different trade-off between simplicity and analysis precision. Experiments with both randomly generated OpenMP task systems and realistic OpenMP programs show that the response time bounds obtained by our approach for tied task systems are very close to that of untied tasks.

  • 255.
    Sundqvist, Albin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Guidelines to Convert Legacy Applications into Docker Container Services2020Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In the past people would buy a program on a disc and install it ontheir local computer or server. Today, cloud computation allows usersto access their applications over the Internet while also providingthem with greater computational speed and storage possibilities. Butmoving existing legacy application into a cloud environment can bedifficult. The goals of this master thesis is to create guidelinesthat describe how the move should be executed, and evaluate thebenefits of moving legacy applications into a containerizedenvironment using Docker and Kubernetes.The work for developing the guidelines was divided into iterations toincrementally build better understanding and allow step-by-stepdevelopment of the method, discovering and focusing on a few newthings each iteration and by doing research in that area. Twoapplications were used and apart from this, research about generalpractices also helped develop the method.Research was conducted to find out what key aspects to consider, andwhat problems and risks to be aware of, from a general stand pointwhen moving an application to a cloud environment. The results aregeneral guidelines on how to move a legacy application intoKubernetes, the advantages it has and which parameters correlate tothese advantages.

    Fulltekst (pdf)
    fulltext
  • 256.
    Sveinsson, Ólafur Björgvin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Measurement setup for High Power Impulse Magnetron Sputtering2011Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Recently material physics group at Science Institute of University of Iceland has been using reactive sputtering to grow thin films used in various research projects at the institute. These films have been grown using dc sputtering which has been proven a very successful method. High power impulse magnetron sputtering or HiPIMS is an new pulsed power sputtering method where shorter but high power pulses are used to sputter over lower steady power.

    The project resulted in a functional system capable of growing thin films using HiPIMS. Thin films grown with high power pulses have a higher film density and other more preferable properties compared to films grown using direct current magnetron sputtering.

    Fulltekst (pdf)
    fulltext
  • 257.
    Svetoft, John
    Högskolan på Gotland, Institutionen för speldesign, teknik och lärande.
    Super-modular Textures: Comparisons in Practical Applications2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The purpose of this thesis is to compare the products of two different work flows in a practical environment. The work flows in question are those of building environments using super-modular textures versus the more conventional method of unique textures. The tests will try to establish whether or not the theory of the super-modular work flow holds up in practice, i.e. if the result is actually as optimized has the theory outlines. The data of interest is gathered through tests in the Unreal Development Kit, which is a free version of the commercial Unreal engine. Results are compiled into graphs in order to give a clear overview of the differences between the two products. The results show that in the context of the tests performed the super-modular workflow allocates less memory than what can be achieved using uniquely mapped assets and that the average draw calls remain the same regardless of method.

    Fulltekst (pdf)
    Super-modular Textures: Comparisons in Practical Applications
  • 258.
    Tachihara, S
    et al.
    Tokyo University of Science.
    Yamaguchi, T
    Tokyo University of Science.
    Ishiura, N
    Harada, T
    DINOMAIS, M
    RICHARD, P
    NGUYEN, S
    Bachelder, Steven
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för speldesign.
    Hayashi, Masaki
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för speldesign.
    Nakajima, Masayuki
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för speldesign.
    FORS, U
    Characterization of engagement changes during VR based rehabilitation: A preliminary study2016Konferansepaper (Annet vitenskapelig)
  • 259.
    Takeuchi, Kohei
    et al.
    Osaka Institute of Technology.
    Hayashi, Masaki
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för speldesign.
    Hirayama, Makoto
    Osaka Institute of Technology.
    An Immersive Virtual Museum Using a Head Mounted Display2019Inngår i: The 6th IIEEJ International Conference on Image Electronics and Visual Computing (IEVC 2019), 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For realistic and comfortable museum experiences, a virtual museum which can be viewed with a head mounted display is developed. Based on an original screen-based virtual museum, virtual reality functions related to a head mounted display are implemented. Unity Game Engine and Oculus Systems are used for the implementation. Four aspects of "Freedom of operation", "Immersion", "Comfort of play", and "Picture quality" are examined to clarify which type of virtual museum would be suitable for any specific user's needs. As a result, a good evaluation was obtained for "Immersion".

  • 260.
    Takeuchi, Kohei
    et al.
    Osaka Inst Technol, Fac Informat Sci & Technol, Osaka, Japan.
    Hayashi, Masaki
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för speldesign.
    Hirayama, Makoto J.
    Osaka Inst Technol, Fac Informat Sci & Technol, Osaka, Japan.
    Development of VR museum and a comparison with the screen-based virtual musuem2019Inngår i: INTERNATIONAL WORKSHOP ON ADVANCED IMAGE TECHNOLOGY (IWAIT) 2019 / [ed] Kemao, Q Hayase, K Lau, PY Lie, WN Lee, YL Srisuk, S Yu, L, SPIE-INT SOC OPTICAL ENGINEERING , 2019, artikkel-id 110491BKonferansepaper (Fagfellevurdert)
    Abstract [en]

    We have been researching and developing virtual museums that can enable a user to appreciate artworks with much reality and less stress as if one is experiencing in actual museums. For this time, as a method to further increase the reality of the virtual museum, we developed a virtual museum using Head Mounted Display. We used Oculus Rift and Unity Game Engine to develop this VR museum. We also performed a comparison of the developed VR museum and the screen-based virtual museum in order to maximize the user experience of the virtual museum. Four aspects of "Freedom of operation". "Immersion", "Comfort of play", and "Picture quality" are examined to clarify which type of virtual museum would be suitable for any specific user's needs.

  • 261.
    tariq, tariq
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media, Informationssystem.
    GUI Application for measuring instrument.: Noise measurement system.2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The always growing demands on the electronics design of modern electron microscopes cause increased requirements to the measurement tasks in the electronics development of these systems. In this thesis, we report the findings of designing noise measurements setup in Carl-Zeiss, Oberkochen. The aim of this thesis was to explore the design setup for noise measurement and to provide an interface which help us analyze these measurements using C# and agilent multimeter. This was achieved by the construction and evaluation of a prototype for a noise measurment application. For this purpose Design Science Research (DSR) was conducted, situated in the domain of noise measurement research. The results consist of a set of design principles expressing key aspects needed to address when designing noise measurement functionality. The artifacts derived from the development and evaluation process each one constitutes an example of how to design for noise measurement functionality of this kind.

    Fulltekst (pdf)
    MasterThesis_UsmanTariq
  • 262.
    Theodoro, Thainan S.
    et al.
    Federal University of Juiz de Fora, Department of Electrical Engineering, Brazil.
    Tomim, Marcelo A.
    Federal University of Juiz de Fora, Department of Electrical Engineering, Brazil.
    Barbosa, Pedro G.
    Federal University of Juiz de Fora, Department of Electrical Engineering, Brazil.
    Lima, Antonio C.S.
    Federal University of Rio de Janeiro, Department of Electrical Engineering, Brazil.
    de Santiago Ochoa, Juan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    A Hybrid Simulation Tool for Distributed Generation Integration Studies2018Inngår i: 2018 Power Systems Computation Conference (PSCC) / [ed] IEEE, Dublin, Ireland: IEEE conference proceedings, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work presents a hybrid simulation tool thatcombines fast analysis of quasi-static time series or transient stability programs and electromagnetic transients ones to evaluatethe dynamic behaviour of electric power systems with distributedgeneration sources. The interaction between the two programs isperformed by means of controllable current and voltage sources,which are used to interface external and detailed systems. Thedouble second order generalized integrator (DSOGI) is used toextract the positive-sequence phasor from the detailed systemto the external one. A local network server controls the datacommunication between the two simulation environments bymeans of the TCP/IP protocol. In the present paper, the proposedtool is used to simulate the integration of a wind power plant,based on a doubly-fed induction generator (DFIG), into a 29-bus electrical network. Results and computational timings arethen compared with the ones obtained with an electromagnetictransients program, which demonstrate the accuracy and speedof the proposed strategy.

  • 263.
    Tobias, Eklund
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för informatik och media.
    Spehar, Joakim
    CPlanner: Kursplaneringsprototyp med Design Science och Scrum2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Utveckling av planeringssystem är ett komplext designproblem som kräver både en hög grad av flexibilitet men även struktur. I samband med planering är det ett flertal aktörer, aktiviteter och resurser som måste beaktas. Kunnandet när det gäller planering finns ofta koncentrerad till ett fåtal nyckelpersoner. Det är därför ingen tillfällighet att många företag, organisationer och även universitet idag bedriver sin planering i beprövade enanvändarsystem som Excel fast att det finns starkt behov för standardiserat fleranvändarsystem. Uppsala universitet är inget undantag trots dess storlek med över 40 000 studenter, 6 200 anställda, 130 utbildningsprogram och 2000 fristående kurser. Kursplaneringen bedrivs med hjälp av enanvändarsystem där man är beroende av ett antal nyckelpersoner för att planeringen skall fungera. Uppsatsens syfte är att undersöka och belysa den problematik som finns i samband med utveckling av planeringssystem genom att utveckla en prototyp för ett kursplaneringssystem. Den forskningsstrategi som används är Design Science och den utvecklingsmetodik som används är Scrum. Prototypen har utvärderats regelbundet under utvecklingen genom formativ utvärdering. Uppsatsens kunskapsbidrag utgörs av metodkunskap som visar hur Scrum och Design Science kan kombineras samt modellkunskap som visar den grundläggande strukturen för ett kursplaneringssystem.

    Fulltekst (pdf)
    fulltext
  • 264.
    Tsuruta, Naoya
    et al.
    Tokyo Univ Technol, Sch Media Sci, Tokyo, Japan.
    Teraoka, Takehiro
    Tokyo Univ Technol, Sch Media Sci, Tokyo, Japan.
    Kondo, Kunio
    Tokyo Univ Technol, Sch Media Sci, Tokyo, Japan.
    Hayashi, Masaki
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Institutionen för speldesign.
    TV Show Template for Text Generated TV2018Inngår i: 2018 International Workshop on Advanced Image Technology (IWAIT), IEEE , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The technique which converts text-based document into a TV show like computer graphics animation has been developed. However, writing a scripting language requires a variety of knowledge on TV shows such as speech timing, camera angle, lighting and so on. In this paper, we propose TV show template that contains animation settings imitating a particular type of TV show and semi-automatic animation generation using it.

  • 265.
    Varshney, Ambuj
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Enabling Sustainable Networked Embedded Systems2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Networked Embedded Systems (NES) are small energy-constrained devices typically with sensors, radio and some form of energy storage. The past several years have seen a rapid growth of applications of NES, with several predictions stating billions of devices deployed in the near future. As NES are deployed at large scale, a growing challenge is to support NES for long periods of time without negatively impacting their physical or the radio environment, i.e., in a sustainable manner. In this dissertation, we identify intertwined challenges that affect the sustainability of NES systems: co-existence on the shared wireless spectrum; energy consumption; and the cost of the deployment and maintenance. We identify research directions to overcome these challenges and address them through the six research papers.

    Firstly, NES have to co-exist with other wireless devices that operate on the shared wireless spectrum. A growing number of devices contending for the spectrum is challenging and leads to increased interference among them. To enable NES to co-exist with other wireless devices, we investigate the use of electronically steerable directional antennas (ESD). ESD antennas allow software-based control of the direction of maximum antenna gain on a per-packet basis and can operate within the severe energy constraints of NES. In the dissertation, we demonstrate that ESD antennas allow solutions that outperform the state-of-the-art in sensing and communication in wireless sensor networks while supporting operations on a single wireless channel reducing the contention on the shared wireless spectrum.

    Secondly, we explore the emerging area of visible light sensing and communication to avoid the crowded radio frequency spectrum. Visible light can be an alternative or a complement to radio frequency for sensing and communication. We make two contributions in the dissertation to make the visible light communication a viable option for NES. We design a novel visible light sensing architecture that supports sensing and communication at tens of microwatts of power. An ultra-low power consumption can make visible light sensing systems pervasive. Our second contribution brings high-speed visible light communication to energy-constrained NES. We design a novel visible light receiver that adapts to the dynamics of changing light conditions, and the energy constraints of the host device while supporting a throughput comparable to radio frequency standards for NES. Through our contribution, we take a significant step to enable visible light-based sustainable NES.

    Finally, replacing batteries on sensor nodes significantly affects the sustainability of NES. Battery-free sensors that harvest small amounts of energy from the ambient environment have a great potential to enable pervasive deployment of NES. To support wide-area deployments of battery-free sensors, we develop an ultra-low power and long-range communication mechanism. We demonstrate the ability to communicate to distances as long as a few kilometres while consuming tens of microwatts at the sensor device. Our contributions pave the way for a wide-area deployment of battery-free sustainable NES.

    Through the contributions made in the dissertation, we take a significant step towards the broader goal of sustainable NES. The work included in the dissertation significantly improves the state-of-the-art in NES, in some case by orders of magnitude.

    Delarbeid
    1. Directional Transmissions and Receptions for High-throughput Bulk Forwarding in Wireless Sensor Networks
    Åpne denne publikasjonen i ny fane eller vindu >>Directional Transmissions and Receptions for High-throughput Bulk Forwarding in Wireless Sensor Networks
    2015 (engelsk)Inngår i: Proceedings of the 13th ACM Conference on Embedded Networked Sensor Systems, 2015, s. 351-364Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    We present DPT: a wireless sensor network protocol for bulk traffic that uniquely leverages electronically switchable directional (ESD) antennas. Bulk traffic is found in several scenarios and supporting protocols based on standard antenna technology abound. ESD antennas may improve performance in these scenarios; for example, by reducing channel contention as the antenna can steer the radiated energy only towards the intended receivers, and by extending the communication range at no additional energy cost. The corresponding protocol support, however, is largely missing. DPT addresses precisely this issue. First, while the network is quiescent, we collect link metrics across all possible antenna configurations. We use this information to formulate a constraint satisfaction problem (CSP) that allows us to find two multi-hop disjoint paths connecting source and sink, along with the corresponding antenna configurations. Domain-specific heuristics we conceive ameliorate the processing demands in solving the CSP, improving scalability. Second, the routing configuration we obtain is injected back into the network. During the actual bulk transfer, the source funnels data through the two paths by quickly alternating between them. Packet forwarding occurs deterministically at every hop. This allows the source to implicitly "clock" the entire pipeline, sparing the need of proactively synchronizing the transmissions across the two paths. Our results, obtained in a real testbed using 802.15.4-compliant radios and custom ESD antennas we built, indicate that DPT approaches the maximum throughput supported by the link layer, peaking at 214 kbit/s in the settings we test.

    Emneord
    Directional antennas; Bulk data transmissions; Wireless sensor networks; Electronically controlled antennas
    HSV kategori
    Forskningsprogram
    Datavetenskap med inriktning mot datorkommunikation
    Identifikatorer
    urn:nbn:se:uu:diva-266348 (URN)10.1145/2809695.2809720 (DOI)000380612400028 ()9781450336314 (ISBN)
    Konferanse
    The 13th ACM Conference on Embedded Networked Sensor Systems (SenSys 2015), November 1-4, 2015, Seoul, South Korea
    Tilgjengelig fra: 2015-11-08 Laget: 2015-11-08 Sist oppdatert: 2018-03-16bibliografisk kontrollert
    2. dRTI: Directional Radio Tomographic Imaging
    Åpne denne publikasjonen i ny fane eller vindu >>dRTI: Directional Radio Tomographic Imaging
    Vise andre…
    2015 (engelsk)Inngår i: Proceedings of the 14th International Conference on Information Processing in Sensor Networks, 2015, s. 166-177Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Radio tomographic imaging (RTI) enables device free localisation of people and objects in many challenging environments and situations. Its basic principle is to detect the changes in the statistics of radio signals due to the radio link obstruction by people or objects. However, the localisation accuracy of RTI suffers from complicated multipath propagation behaviours in radio links. We propose to use inexpensive and energy efficient electronically switched directional (ESD) antennas to improve the quality of radio link behaviour observations, and therefore, the localisation accuracy of RTI. We implement a directional RTI (dRTI) system to understand how directional antennas can be used to improve RTI localisation accuracy. We also study the impact of the choice of antenna directions on the localisation accuracy of dRTI and propose methods to effectively choose informative antenna directions to improve localisation accuracy while reducing overhead. Furthermore, we analyse radio link obstruction performance in both theory and simulation, as well as false positives and false negatives of the obstruction measurements to show the superiority of the directional communication for RTI. We evaluate the performance of dRTI in diverse indoor environments and show that dRTI significantly outperforms the existing RTI localisation methods based on omni-directional antennas.

    Serie
    IPSN ’15
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-252426 (URN)10.1145/2737095.2737118 (DOI)
    Konferanse
    ACM/IEEE IPSN 2015
    Tilgjengelig fra: 2015-05-06 Laget: 2015-05-06 Sist oppdatert: 2018-03-16
    3. LoRea: A backscatter architecture that achieves a long communication range
    Åpne denne publikasjonen i ny fane eller vindu >>LoRea: A backscatter architecture that achieves a long communication range
    Vise andre…
    2017 (engelsk)Inngår i: Proc. 15th ACM Conference on Embedded Network Sensor Systems, New York: ACM Press, 2017Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    There is the long-standing assumption that radio communication in the range of hundreds of meters needs to consume mWs of power at the transmitting device. In this paper, we demonstrate that this is not necessarily the case for some devices equipped with backscatter radios. We present LoRea an architecture consisting of a tag, a reader and multiple carrier generators that overcomes the power, cost and range limitations of existing systems such as Computational Radio Frequency Identification (CRFID). LoRea achieves this by: First, generating narrow-band backscatter transmissions that improve receiver sensitivity. Second, mitigating self-interference without the complex designs employed on RFID readers by keeping carrier signal and backscattered signal apart in frequency. Finally, decoupling carrier generation from the reader and using devices such as WiFi routers and sensor nodes as a source of the carrier signal. An off-the-shelf implementation of LoRea costs 70 USD, a drastic reduction in price considering commercial RFID readers cost 2000 USD. LoRea's range scales with the carrier strength, and proximity to the carrier source and achieves a maximum range of 3.4 km when the tag is located at 1m distance from a 28 dBm carrier source while consuming 70 mu W at the tag. When the tag is equidistant from the carrier source and the receiver, we can communicate upto 75m, a significant improvement over existing RFID readers.

    sted, utgiver, år, opplag, sider
    New York: ACM Press, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-335566 (URN)10.1145/3131672.3131691 (DOI)000462783500018 ()978-1-4503-5459-2 (ISBN)
    Konferanse
    SenSys 2017, November 5–8, Delft, The Netherlands
    Tilgjengelig fra: 2017-11-05 Laget: 2017-12-06 Sist oppdatert: 2019-08-28bibliografisk kontrollert
    4. Towards wide-area backscatter networks
    Åpne denne publikasjonen i ny fane eller vindu >>Towards wide-area backscatter networks
    2017 (engelsk)Inngår i: Proc. 4th ACM Workshop on Hot Topics in Wireless, New York: ACM Press, 2017, s. 49-53Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    New York: ACM Press, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-335565 (URN)10.1145/3127882.3127888 (DOI)978-1-4503-5140-9 (ISBN)
    Konferanse
    HotWireless 2017, October 16, Snowbird, UT
    Tilgjengelig fra: 2017-10-16 Laget: 2017-12-06 Sist oppdatert: 2020-03-28
    5. Battery-free Visible Light Sensing
    Åpne denne publikasjonen i ny fane eller vindu >>Battery-free Visible Light Sensing
    2017 (engelsk)Inngår i: Proc. 4th ACM Workshop on Visible Light Communication Systems, New York: ACM Press, 2017, s. 3-8Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    New York: ACM Press, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-335564 (URN)10.1145/3129881.3129890 (DOI)978-1-4503-5142-3 (ISBN)
    Konferanse
    VLCS 2017, October 16, Snowbird, UT
    Tilgjengelig fra: 2017-10-16 Laget: 2017-12-06 Sist oppdatert: 2018-03-16bibliografisk kontrollert
    6. Visible Light Communication for Wearable Computing
    Åpne denne publikasjonen i ny fane eller vindu >>Visible Light Communication for Wearable Computing
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Visible Light Communication (VLC) is emerging as a means to network computing devices that ameliorates many hurdles of radio-frequency (RF) communications, for example, the limited available spectrum. Enabling VLC in wearable computing, however, is challenging because mobility induces unpredictable drastic changes in light conditions, for example, due to reflective surfaces and obstacles casting shadows.We experimentally demonstrate that such changes are so extreme that no single design of a VLC receiver can provide efficient performance across the board. The diversity found in current wearable devices complicates matters. Based on these observations, we present three different designs of VLC receivers that i) are individual orders of magnitude more efficient than the state-of-the-art in a subset of the possible conditions, and ii) can be combined in a single unit that dynamically switches to the best performing receiver based on the light conditions.Our evaluation indicates that dynamic switching incurs minimal overhead, that we can obtain throughput in the order of MBit/s, and at energy costs lower than many RF devices.

    HSV kategori
    Forskningsprogram
    Datavetenskap med inriktning mot datorkommunikation
    Identifikatorer
    urn:nbn:se:uu:diva-346820 (URN)
    Tilgjengelig fra: 2018-03-21 Laget: 2018-03-21 Sist oppdatert: 2018-03-23
    Fulltekst (pdf)
    fulltext
  • 266.
    Varshney, Ambuj
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Mottola, Luca
    SICS Swedish ICT, Sweden and Politecnico di Milano, Italy.
    Carlsson, Mats
    SICS Swedish ICT, Sweden.
    Voigt, Thiemo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Directional Transmissions and Receptions for High-throughput Bulk Forwarding in Wireless Sensor Networks2015Inngår i: Proceedings of the 13th ACM Conference on Embedded Networked Sensor Systems, 2015, s. 351-364Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present DPT: a wireless sensor network protocol for bulk traffic that uniquely leverages electronically switchable directional (ESD) antennas. Bulk traffic is found in several scenarios and supporting protocols based on standard antenna technology abound. ESD antennas may improve performance in these scenarios; for example, by reducing channel contention as the antenna can steer the radiated energy only towards the intended receivers, and by extending the communication range at no additional energy cost. The corresponding protocol support, however, is largely missing. DPT addresses precisely this issue. First, while the network is quiescent, we collect link metrics across all possible antenna configurations. We use this information to formulate a constraint satisfaction problem (CSP) that allows us to find two multi-hop disjoint paths connecting source and sink, along with the corresponding antenna configurations. Domain-specific heuristics we conceive ameliorate the processing demands in solving the CSP, improving scalability. Second, the routing configuration we obtain is injected back into the network. During the actual bulk transfer, the source funnels data through the two paths by quickly alternating between them. Packet forwarding occurs deterministically at every hop. This allows the source to implicitly "clock" the entire pipeline, sparing the need of proactively synchronizing the transmissions across the two paths. Our results, obtained in a real testbed using 802.15.4-compliant radios and custom ESD antennas we built, indicate that DPT approaches the maximum throughput supported by the link layer, peaking at 214 kbit/s in the settings we test.

    Fulltekst (pdf)
    fulltext
  • 267.
    Varshney, Ambuj
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Mottola, Luca
    SICS Swedish ICT, Sweden and Politecnico di Milano, Italy.
    Voigt, Thiemo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Coordination of Wireless Sensor Networks using Visible Light2015Inngår i: SenSys '15 Proceedings of the 13th ACM Conference on Embedded Networked Sensor Systems, 2015, s. 421-422Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Wireless sensor networks are often deployed indoors where artificial lighting is present. Indoor lighting is increasingly being composed of Light Emitting Diodes (LEDs) that offer the ability to precisely control the intensity and the frequency of the light carrier. This can be used to coordinate wireless sensor networks (WSN). The periodic variations in the light intensity can synchronise the clocks on the sensor nodes, while the ability to modulate the light carrier enables the transmission of control information like channel assignment or transmission schedules.We present Guidelight, a simple mechanism that uses controlled fluctuations in the light intensity to coordinate sensor nodes. Guidelight can wake-up or time synchronise sensor nodes or even send small bits of control information to them. All of these have separate dedicated solutions in WSN. Guidelight aims to provide a single solution to all these problems. Our initial experiments demonstrate the ability of Guidelight to trigger sensor nodes. We demonstrate Guidelight is able to trigger sensor nodes selectively at a mean error of 21 μ s.

  • 268.
    Voigt, Thiemo
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Hewage, Kasun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Alm, Per
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Logopedi.
    Smartphone Support for Persons Who Stutter2014Inngår i: Proc. 13th International Symposium on Information Processing in Sensor Networks, Piscataway, NJ: IEEE Press, 2014, s. 293-294Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Stuttering is a very complex speech disorder that affects around 0.7% of adults while around 5% of the population have stuttered at some point. A large percentage of the affected people tend to speak more fluently when their own speech is played back to their ear with some type of alteration. While this has been done with special devices, smartphones can be used for this purpose. We report on our initial experiences on building such an application and demonstrate problems with delay caused by the lack of real-time support for audio playback in the Android operating system. We also discuss ideas for future work to improve app support for people who stutter.

  • 269.
    Wajima, Koji
    et al.
    Tokyo University of Science.
    Hayashi, Masaki
    Högskolan på Gotland, Institutionen för speldesign, teknik och lärande.
    Hurukawa, Toshihiro
    Tokyo University of Science.
    On reusable CG object for MMD in T2V2013Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Production of Computer Graphics (CG) by individuals has become active. CG movie production free tool called MMD (MikuMikuDance) is famous for its volunteers to produce CG character animations. Videos that have been produced in MMD are very popular among the fans of the character. Many people want to create their own animations, however, the production tool requires highly technical skill, and therefore, there is a big barrier for such individual people to create animations with the MMD. On the other hand, T2V (Text-To-Vision) is proposed to provide the easy-to-use production tool of character animation for the people who do not have much skill of making animations. Considering reuse of CG object of MMD in T2V to allow users to make animation in the easy way, we can expect the further development of content sharing sites. In this paper, we compare the CG formats of each of the MMD and T2V then we have had a test rendering to validate our method. We then clarify the issue of CG object reuse of MMD and T2V for the future applications.

    Fulltekst (pdf)
    fulltext
  • 270.
    Wang, Xiaojie
    et al.
    NeuSoft Corp, Shenyang, Liaoning, Peoples R China; Dalian Univ Technol, Sch Software, Dalian, Peoples R China.
    Ning, Zhaolong
    Dalian Univ Technol, Sch Software, Dalian, Peoples R China; Kyushu Univ, Fukuoka, Fukuoka, Japan.
    Hu, Xiping
    Chinese Acad Sci, Shenzhen Inst Adv Technol, Beijing, Peoples R China.
    Ngai, Edith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Imperial Coll London, London, England.
    Wang, Lei
    Dalian Univ Technol, Sch Software, Dalian, Peoples R China; Bell Labs Res China, Shanghai, Peoples R China; Samsung, Seoul, South Korea; Washington State Univ, Vancouver, WA USA.
    Hu, Bin
    Lanzhou Univ, Sch Informat Sci & Engn, Lanzhou, Gansu, Peoples R China; Tsinghua Univ, Beijing, Peoples R China; Swiss Fed Inst Technol, Zurich, Switzerland; ACM China, Beijing, Peoples R China.
    Kwok, Ricky
    Univ Hong Kong, Hong Kong, Hong Kong, Peoples R China; HKIE, Hong Kong, Hong Kong, Peoples R China; IET, Hong Kong, Hong Kong, Peoples R China.
    A City-Wide Real-Time Traffic Management System: Enabling Crowdsensing in Social Internet of Vehicles2018Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 56, nr 9, s. 19-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As an emerging platform based on ITS, SIoV is promising for applications of traffic management and road safety in smart cities. However, the end-to-end delay is large in store-carry-and-forward-based vehicular networks, which has become the main obstacle for the implementation of large-scale SIoV. With the extensive applications of mobile devices, crowdsensing is promising to enable real-time content dissemination in a city-wide traffic management system. This article first provides an overview of several promising research areas for traffic management in SIoV. Given the significance of traffic management in urban areas, we investigate a crowdsensing-based framework to provide timely response for traffic management in heterogeneous SIoV. The participant vehicles based on D2D communications integrate trajectory and topology information to dynamically regulate their social behaviors according to network conditions. A real-world taxi trajectory analysis-based performance evaluation is provided to demonstrate the effectiveness of the designed framework. Furthermore, we discuss several future research challenges before concluding our work.

    Fulltekst (pdf)
    fulltext
  • 271.
    Wang, Yang
    et al.
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Guan, Nan
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Sun, Jinghao
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Lv, Mingsong
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    He, Qingqiang
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    He, Tianzhang
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Benchmarking OpenMP Programs for Real-Time Scheduling2017Inngår i: 2017 IEEE 23Rd International Conference On Embedded And Real-Time Computing Systems And Applications (RTSCA), IEEE Computer Society, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-time systems are shifting from single-core to multi-core processors. Software must be parallelized to fully utilize the computation power of multi-core architecture. OpenMP is a popular parallel programming framework in general and high-performance computing, and recently has drawn a lot of interests in embedded and real-time computing. Much recent work has been done on real-time scheduling of OpenMP-based parallel workload. However, these studies conduct evaluations with randomly generated task systems, which cannot well represent the structure features of OpenMP workload. This paper presents a benchmark suite, ompTGB, to support research on real-time scheduling of OpenMP-based parallel tasks. ompTGB does not only collect realistic OpenMP programs, but also models them into task graphs so that the real-time scheduling researchers can easily understand and use them. We also present a new response time bound for a subset of OpenMP programs and use it to demonstrate the usage of ompTGB.

  • 272.
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Towards Customizable CPS: Composability, Efficiency and Predictability2017Inngår i: Formal Methods and Software Engineering / [ed] Duan, Z Ong, L, Springer, 2017, s. 3-15Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today, many industrial products are defined by software, and therefore customizable by installing new applications on demand - their functionalities are implemented by software and can be modified and extended by software updates. This trend towards customizable products is extending into all domains of IT, including Cyber-Physical Systems (CPS) such as cars, robotics, and medical devices. However, these systems are often highly safety-critical. The current state-of-practice allows hardly any modifications once safety-critical systems are put in operation. This is due to the lack of techniques to preserve crucial safety conditions for the modified system, which severely restricts the benefits of software. This work aims at new paradigms and technologies for the design and safe software updates of CPS at operation-time - subject to stringent timing constraints, dynamic workloads, and limited resources on complex computing platforms. Essentially there are three key challenges: Composability, Resource-Efficiency and Predictability to enable modular, incremental and safe software updates over system life-time in use. We present research directions to address these challenges: (1) Open architectures and implementation schemes for building composable systems, (2) Fundamental issues in real-time scheduling aiming at a theory of multi-resource (inc. multiprocessor) scheduling, and (3) New-generation techniques and tools for fully separated verification of timing and functional properties of real-time systems with significantly improved efficiency and scalability. The tools shall support not only verification, but also code generation tailored for both co-simulation (interfaced) with existing design tools such as Open Modelica (for modeling and simulation of physical components), and deployment on given computing platforms.

  • 273.
    Wei, Bo
    et al.
    University of New South Wales, Sydney, Australia and CSIRO, Brisbane, Australia and SICS, Stockholm, Sweden.
    Varshney, Ambuj
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Patwari, Neal
    University of Utah, Salt Lake City and Xandem Technology, Salt Lake City.
    Hu, Wen
    University of New South Wales, Sydney, Australia and CSIRO, Brisbane, Australia and SICS, Stockholm, Sweden.
    Voigt, Thiemo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Chou, Chun Tung
    University of New South Wales, Sydney, Australia.
    dRTI: Directional Radio Tomographic Imaging2015Inngår i: Proceedings of the 14th International Conference on Information Processing in Sensor Networks, 2015, s. 166-177Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Radio tomographic imaging (RTI) enables device free localisation of people and objects in many challenging environments and situations. Its basic principle is to detect the changes in the statistics of radio signals due to the radio link obstruction by people or objects. However, the localisation accuracy of RTI suffers from complicated multipath propagation behaviours in radio links. We propose to use inexpensive and energy efficient electronically switched directional (ESD) antennas to improve the quality of radio link behaviour observations, and therefore, the localisation accuracy of RTI. We implement a directional RTI (dRTI) system to understand how directional antennas can be used to improve RTI localisation accuracy. We also study the impact of the choice of antenna directions on the localisation accuracy of dRTI and propose methods to effectively choose informative antenna directions to improve localisation accuracy while reducing overhead. Furthermore, we analyse radio link obstruction performance in both theory and simulation, as well as false positives and false negatives of the obstruction measurements to show the superiority of the directional communication for RTI. We evaluate the performance of dRTI in diverse indoor environments and show that dRTI significantly outperforms the existing RTI localisation methods based on omni-directional antennas.

  • 274.
    Yang, Yu
    et al.
    Royal Inst Technol KTH, Stockholm, Sweden.
    Stathis, Dimitrios
    Royal Inst Technol KTH, Stockholm, Sweden.
    Sharma, Prashant
    Royal Inst Technol KTH, Stockholm, Sweden.
    Paul, Kolin
    Indian Inst Technol Delhi, Delhi, India.
    Hemani, Ahmed
    Royal Inst Technol KTH, Stockholm, Sweden.
    Grabherr, Manfred
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk biokemi och mikrobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär evolution.
    Ahmad, Rafi
    Inland Norway Univ Appl Sci, Hamar, Norway.
    RiBoSOM: Rapid Bacterial Genome Identification Using Self-Organizing Map implemented on the Synchoros SiLago Platform2018Inngår i: 2018 International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS XVIII), Association for Computing Machinery (ACM), 2018, s. 105-114Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Artificial Neural Networks have been applied to many traditional machine learning applications in image and speech processing. More recently, ANNs have caught attention of the bioinformatics community for their ability to not only speed up by not having to assemble genomes but also work with imperfect data set with duplications. ANNs for bioinformatics also have the added attraction of better scaling for massive parallelism compared to traditional bioinformatics algorithms. In this paper, we have adapted Self-organizing Maps for rapid identification of bacterial genomes called BioSOM. BioSOM has been implemented on a design of two coarse grain reconfigurable fabrics customized for dense linear algebra and streaming scratchpad memory respectively. These fabrics are implemented in a novel synchoros VLSI design style that enables composition by abutment. The synchoricity empowers rapid and accurate synthesis from Matlab models to create near ASIC like efficient solution. This platform, called SiLago (Silicon Lego) is benchmarked against a GPU implementation. The SiLago mentation of BioSOMs in four different dimensions, 128, 256, 512 and 1024 Neurons, were trained for two E Coli strains of bacteria with 40K training vectors. The results of SiLago implementation were benchmarked against a GPU GTX 1070 implementation in the CUDA framework. The comparison reveals 4 to 140x speed up and 4 to 5 orders of improvement in energy-delay product compared to implementation on GPU. This extreme efficiency comes with the added benefit of automated generation of GDSII level design from Matlab by using the Synchoros VLSI design style.

  • 275.
    Zafari, Afshin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Advances in Task-Based Parallel Programming for Distributed Memory Architectures2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    It has become common knowledge that parallel programming is needed for scientific applications, particularly for running large scale simulations. Different programming models are introduced for simplifying parallel programming, while enabling an application to use the full computational capacity of the hardware. In task-based programming, all the variables in the program are abstractly viewed as data. Parallelism is provided by partitioning the data. A task is a collection of operations performed on input data to generate output data. In distributed memory environments, the data is distributed over the computational nodes (or processes), and is communicated when a task needs remote data.

    This thesis discusses advanced techniques in distributed task-based parallel programming, implemented in the DuctTeip software library. DuctTeip uses MPI (Message Passing Interface) for asynchronous inter-process communication and Pthreads for shared memory parallelization within the processes. The data dependencies that determine which subsets of tasks can be executed in parallel are extracted from information about the data accesses (input or output) of the tasks. A versioning system is used internally to represent the task-data dependencies efficiently. A hierarchical partitioning of tasks and data allows for independent optimization of the size of computational tasks and the size of communicated data. A data listener technique is used to manage communication efficiently.

    DuctTeip provides an algorithm independent dynamic load balancing functionality. Redistributing tasks from busy processes to idle processes dynamically can provide an overall shorter execution time. A random search method with high probability of success is employed for locating idle/busy nodes.

    The advantage of the abstract view of tasks and data is exploited in a unified programming interface, which provides a standard for task-based frameworks to decouple framework development from application development. The interface can be used for collaboration between different frameworks in running an application program efficiently on different hardware.

    To evaluate the DuctTeip programming model, applications such as Cholesky factorization, a time-dependent PDE solver for the shallow water equations, and the fast multipole method have been implemented using DuctTeip. Experiments show that DuctTeip provides both scalability and performance. Comparisons with similar frameworks such as StarPU, OmpSs, and PaRSEC show competitive results.

    Delarbeid
    1. Programming models based on data versioning for dependency-aware task-based parallelisation
    Åpne denne publikasjonen i ny fane eller vindu >>Programming models based on data versioning for dependency-aware task-based parallelisation
    2012 (engelsk)Inngår i: Proc. 15th International Conference on Computational Science and Engineering, Los Alamitos, CA: IEEE Computer Society, 2012, s. 275-280Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Los Alamitos, CA: IEEE Computer Society, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-187446 (URN)10.1109/ICCSE.2012.45 (DOI)000317475000038 ()978-1-4673-5165-2 (ISBN)
    Konferanse
    CSE 2012
    Prosjekter
    eSSENCEUPMARC
    Tilgjengelig fra: 2013-01-24 Laget: 2012-12-06 Sist oppdatert: 2018-01-16bibliografisk kontrollert
    2. DuctTeip: An efficient programming model for distributed task-based parallel computing
    Åpne denne publikasjonen i ny fane eller vindu >>DuctTeip: An efficient programming model for distributed task-based parallel computing
    2019 (engelsk)Inngår i: Parallel Computing, ISSN 0167-8191, E-ISSN 1872-7336, Vol. 90, artikkel-id 102582Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-338832 (URN)10.1016/j.parco.2019.102582 (DOI)000501649400002 ()
    Prosjekter
    UPMARCeSSENCE
    Tilgjengelig fra: 2019-11-04 Laget: 2018-01-14 Sist oppdatert: 2020-01-24bibliografisk kontrollert
    3. TaskUniVerse: A Task-Based Unified Interface for Versatile Parallel Execution
    Åpne denne publikasjonen i ny fane eller vindu >>TaskUniVerse: A Task-Based Unified Interface for Versatile Parallel Execution
    2018 (engelsk)Inngår i: Parallel Processing and Applied Mathematics: Part I, Springer, 2018, s. 169-184Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Springer, 2018
    Serie
    Lecture Notes in Computer Science ; 10777
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-338836 (URN)10.1007/978-3-319-78024-5_16 (DOI)000458563300016 ()978-3-319-78023-8 (ISBN)
    Konferanse
    PPAM 2017
    Prosjekter
    eSSENCE
    Tilgjengelig fra: 2018-03-23 Laget: 2018-01-14 Sist oppdatert: 2019-03-14bibliografisk kontrollert
    4. Parallelization of hierarchical matrix algorithms for electromagnetic scattering problems
    Åpne denne publikasjonen i ny fane eller vindu >>Parallelization of hierarchical matrix algorithms for electromagnetic scattering problems
    Vise andre…
    2019 (engelsk)Inngår i: High-Performance Modelling and Simulation for Big Data Applications, Springer, 2019, s. 36-68Kapittel i bok, del av antologi (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Springer, 2019
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-338833 (URN)10.1007/978-3-030-16272-6_2 (DOI)978-3-030-16271-9 (ISBN)
    Prosjekter
    eSSENCE
    Tilgjengelig fra: 2019-03-26 Laget: 2018-01-14 Sist oppdatert: 2019-03-29bibliografisk kontrollert
    5. Distributed dynamic load balancing for task parallel programming
    Åpne denne publikasjonen i ny fane eller vindu >>Distributed dynamic load balancing for task parallel programming
    2018 (engelsk)Inngår i: Computing Research Repository, nr 1801.04582Artikkel i tidsskrift (Annet vitenskapelig) Submitted
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-338835 (URN)
    Prosjekter
    UPMARCeSSENCE
    Tilgjengelig fra: 2018-01-14 Laget: 2018-01-14 Sist oppdatert: 2018-04-18bibliografisk kontrollert
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  • 276.
    Zak, Edvard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    Including Smartphone End User Apps in the Context of the Company Contact Center2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Smartphones are becoming increasingly popular, with the result that customers prefer to carry out at least some customer services using an app on a mobile device. Among app users, smooth transfer to a live agent is seen as an important feature and this means that the company contact center need a solution to handle this as well as increasing numbers of interactions. The question this thesis tries to answer is "how can smartphone end user apps be included in the context of the company contact center"? To answer this question research was conducted regarding the possibilities of an Android smartphone, with the results of this research being used to define a use case, a state flow diagram and create a demonstration app. The thesis showed that it is possible to have an app as an online channel for customer service interactions. New possibilities in comparison to traditional telephony include that customer data such as topic, authentication, location and multimedia can be sent to the contact center before an actual interaction is started.

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