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  • 451.
    Wolkerstorfer, Martin
    et al.
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Jaldén, Joakim
    ACCESS Linnaeus Center, Signal Processing Lab, KTH Royal Institute of Technology, Stockholm, Sweden.
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Column Generation for Discrete-Rate Multi-User and Multi-Carrier Power Control2012Inngår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 60, nr 9, s. 2712-2722Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We consider a constrained multi-carrier power allocation problem in interference-limited multi-user systems with a finite set of transmission rates. The Lagrange relaxation is a common technique for decomposing such problems into independently solvable per-subcarrier problems. Deviating from this approach our main contribution is the proposal of a novel spectrum management framework based on a Nonlinear Dantzig-Wolfe problem decomposition. It allows for suboptimal initialization and suboptimal power allocation methods with low complexity. While we show that the combinatorial per-subcarrier problems have polynomial complexity in the number of users, we find that such suboptimal methods are indispensable in large systems. Thus we give an overview of various basic dual heuristics and provide simulation results on a set of thousand digital subscriber line (DSL) networks which show the superior performance of our framework compared to previous power control algorithms. © 2012 IEEE.

  • 452.
    Wolkerstorfer, Martin
    et al.
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Jaldén, Joakim
    KTH, Stockholm, Sverige.
    Nordström, Tomas
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Low-Complexity Optimal Discrete-Rate Spectrum Balancing in Digital Subscriber Lines2013Inngår i: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 93, nr 1, s. 23-34Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Discrete-rate spectrum balancing in interference-limited multi-user and multi-carrier digital subscriber lines (DSL) is a large-scale, non-convex and combinatorial problem. Previously proposed algorithms for its (dual) optimal solution are only applicable for networks with few users, while the suboptimality of less complex bit-loading algorithms has not been adequately studied so far. We deploy constrained optimization techniques as well as problem-specific branch-and-bound and search-space reduction methods, which for the first time give a low-complexity guarantee of optimality in certain multi-user DSL networks of practical size. Simulation results precisely quantify the suboptimality of multi-user bit-loading schemes in a thousand ADSL2 scenarios under measured channel data.

  • 453.
    Wolkerstorfer, Martin
    et al.
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Comparative Simulation Study of Fast Heuristics for Power Control in Copper Broadband Networks2014Inngår i: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 104, nr November 2014, s. 437-449Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The data-rate in currently deployed multi-carrier digital subscriber line (DSL) communication systems is limited by the interference among copper lines. This interference can be alleviated by multi-user transmit power allocation. Problem decomposition results in a large number of per-subcarrier problems. Our objective is to solve these nonconvex integer per-subcarrier power control problems at low complexity. For this purpose we develop ten combinatorial heuristics and test them by simulation under a small complexity budget in scenarios with tens of DSL users, where optimal solutions are currently intractable. Simulation results lead us to the conclusion that simple randomized greedy heuristics extended by a specific local search perform well despite the stringent complexity restriction. This has implications on multi-user discrete resource allocation algorithms, as these can be designed to jointly optimize transmit power among users even in large-scale scenarios.

  • 454.
    Wolkerstorfer, Martin
    et al.
    FTW, Austria.
    Nordström, Tomas
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Krasniqi, Bujar
    Vienna University of Technology.
    Wrulich, Martin
    Vienna University of Technology.
    Mecklenbräuker, Christopher
    Vienna University of Technology.
    OFDM/OFDMA Subcarrier Allocation2011Inngår i: Cross Layer Designs in WLAN Systems / [ed] N. Zorba, C. Skianis and C. Verikoukis, Troubador Publishing Ltd, 2011, s. 161-192Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 455.
    Wolkerstorfer, Martin
    et al.
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Statovci, Driton
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Enabling Greener DSL Access Networks by their Stabilization with Artificial Noise and SNR Margin2013Inngår i: Cluster Computing, ISSN 1386-7857, E-ISSN 1573-7543, Vol. 16, nr 3, s. 407-419Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low-power modes (LPM) are a standardized means in asymmetric digital subscriber lines (ADSL) 2 for reducing the power consumption at the central office. However, the activation of LPMs is hampered by the operators’ concern for instability introduced by frequent transmit power changes. The injection of artificial noise (AN) has been proposed as a standard-compliant stabilization technique. We develop an analytical solution for setting the AN power spectrum. Based on this solution we jointly optimize the AN power spectrum and the signal-to-noise ratio (SNR) margin. Simulation results show the performance gain in terms of rate and energy compared to heuristic rules for setting the AN power spectrum. We propose and demonstrate three approaches for evaluating the performance of AN-enabled DSL systems, including (a) joint spectrum balancing, AN, and margin optimization, (b) single-user worst-case-stable optimization, and (c) worst-case-stable optimization based on sequential initialization. Simulation results confirm a strong dependency of the performance under AN on the selected SNR margins, and highlight the total AN power consumption as well as the residual energy savings under low-power modes stabilized by AN. © 2012 The Author(s).

  • 456.
    Wolkerstorfer, Martin
    et al.
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Statovci, Driton
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Energy-saving by Low-Power Modes in ADSL22012Inngår i: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 56, nr 10, s. 2468-2480Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The large number of broadband users and its forecast growth has recently triggered research on energy-efficiency in digital subscriber lines (DSLs). A promising technique are low-power modes (LPMs) as standardized in asymmetric DSL 2 (ADSL2) which let the DSL connection operate in downstream direction with reduced transmit rate and power. We study the problem of optimizing the LPM rate-level for energy-efficiency. A traffic-independent rate setting is proposed based on an analytical competitive framework. Also, a Markov chain based LPM model is derived which facilitates the fast numerical optimization of the LPM rate-level under realistic traffic models and system constraints. Simulation results under various traffic settings and DSL scenarios demonstrate energy savings by LPMs of around 30–40% of the ADSL2 transceiver’s power consumption. Furthermore, they provide insights on how to set the LPM rate-levels in practice for energy-efficient DSL operation. © 2012 Elsevier B.V. All rights reserved.

  • 457.
    Wolkerstorfer, Martin
    et al.
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Trautmann, Steffen
    Lantiq A GmbH, Villach, Austria.
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Putra, Bakti
    FTW Telecommunications Research Center Vienna, Vienna, Austria.
    Modeling and Optimization of Line-Driver Power Consumption in xDSL Systems2012Inngår i: EURASIP Journal on Advances in Signal Processing, ISSN 1687-6172, E-ISSN 1687-6180, Vol. 2012, artikkel-id 226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimization of the power spectrum alleviates the crosstalk noise in Digital Subscriber Lines (DSL) and thereby reduces their power consumption at present. In order to truly assess the DSL system power consumption, thispaper presents realistic line driver (LD) power consumption models. These are applicable to any DSL system andextend previous models by parameterizing various circuit-level non-idealities. Based on the model of a class-ABLD we analyze the multi-user power spectrum optimization problem and propose novel algorithms for its global or approximate solution. The thereby obtained simulation results support our claim that this problem can besimplified with negligible performance loss by neglecting the LD model. This motivates the usage of established spectral optimization algorithms, which are shown to significantly reduce the LD power consumption comparedto static spectrum management.

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  • 458.
    Xiang, Yang
    et al.
    Deakin University, Burwood VIC, Australia.
    Taha, Walid
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Wang, Hua
    University of Southern Queensland, Toowoomba QL, Australia.
    EUC 2011: Message from the program committee chairs2011Inngår i: Proceedings - 2011 IFIP 9th International Conference on Embedded and Ubiquitous Computing, EUC 2011, s. xiii-xiiiArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Presents the welcome message from the conference proceedings.

  • 459.
    Xu, Bingyu
    et al.
    Queen Mary University of London, London, United Kingdom.
    Chen, Yue
    Queen Mary University of London, London, United Kingdom.
    Requena Carrión, Jesús
    Queen Mary University of London, London, United Kingdom.
    Loo, Jonathan
    Middlesex University, London, United Kingdom.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Energy-aware Power Control in Energy Cooperation Aided Millimeter Wave Cellular Networks with Renewable Energy Resources2016Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5, s. 432-442Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Increased energy consumption becomes a major issue in 5G cellular networks, which inspires the network operators to deploy renewable energy sources. However, due to the fluctuating nature of renewable energy sources, the energy harvested by base stations (BSs) may not fit for their load conditions. The transmit power of the BS needs to be redesigned again. Hence, this paper considers power control in energy cooperation enabled millimeter wave (mmWave) networks, to alleviate the harvested energy imbalance problem and reduce the energy waste. Each BS is solely powered by renewable energy sources and the harvested energy is allowed to be transferred between BSs. Each BS needs to determine whether the energy should be stored in the battery or transferred to others at each time slot. In this work, power control is formulated as a stochastic optimization problem, aiming at maximizing the time average network utility while keeping the network stable. An online algorithm called Dynamic Energy-aware Power Allocation (DEPA) is proposed based on Lyapunov optimization, which does not need to acquire any statistical knowledge of channels and traffic arrivals. Simulation results show that compared with the power control scheme without energy cooperation, the proposed algorithm with energy cooperation can achieve higher network sum rate while reducing the delay and the required battery capacity.

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  • 460.
    Xypolitidis, Benard
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Shabani, Rudin
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Khanderparkar, Satej V.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Ul-Abdin, Zain
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Savas, Süleyman
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Towards Architectural Design Space Exploration for Heterogeneous Manycores2016Inngår i: Proceedings: 24th Euromicro International Conference on Parallel, Distributed, and Network-Based Processin: PDP 2016 / [ed] Yiannis Cotronis, Masoud Daneshtalab & George Angelos Papadopoulos, Piscataway, NJ: IEEE Computer Society, 2016, s. 805-810Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today many of the high performance embedded processors already contain multiple processor cores and we see heterogeneous manycore architectures being proposed. Therefore it is very desirable to have a fast way to explore various heterogeneous architectures through the use of an architectural design space exploration tool, giving the designer the option to explore design alternatives before the physical implementation. In this paper, we have extended Heracles, a design space exploration tool for (homogeneous) manycore architectures, to incorporate different types of processing cores, and thus allowus to model heterogeneity. Our tool, called the Heterogeneous Heracles System (HHS), can besides the already supported MIPS core also include OpenRISC cores. The new tool retains the possibility available in Heracles to perform register transfer level (RTL) simulations of each explored architecture in Verilog as well as synthesizing it to field-programmable gate arrays (FPGAs). To facilitate the exploration of heterogeneous architectures, we have also extended the graphical user interface (GUI) to support heterogeneity. This GUI provides options to configure the types of core, core settings, memory system and network topology. Some initial results on FPGA utilization are presented from synthesizing both homogeneous and heterogeneous manycore architectures, as well as some benchmark results from both simulated and synthesized architectures.

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  • 461.
    Yang Lin, Shih
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Englund, Cristofer
    Viktoria Swedish ICT, Gothenburg, Sweden.
    Chen, Lei
    Viktoria Swedish ICT, Gothenburg, Sweden.
    Poster: Adaptive Wavelength Adjustment (AWLA) for Cooperative Speed Harmonization2014Inngår i: 2014 IEEE Vehicular Networking Conference (VNC) / [ed] Falko Dressler, Onur Altintas, Suman Banerjee, Björn Scheuermann & David Eckhoff, Piscataway, NJ: IEEE Press, 2014, s. 113-114Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Traffic merge on express-ways creates bottlenecks for traffic flow that potentially lead to traffic jams, especially in dense traffic. Cooperative speed harmonization (CSH), where vehicles are grouped and associated to virtual speed waves for group-wise joining at intersections, is proven to be efficient for on-ramp traffic merge. Based on CSH and considering variations of traffic density from joining roads, an adaptive wavelength adjustment (AWLA) mechanism is proposed in this paper. AWLA extends CSH by dynamically adjusting the length of segments in virtual waves according to the traffic densities of the joining roads. Therefore, roads with denser traffic may have larger segments to carry more vehicles through the intersection, which may improve the overall performance. Simulation results have shown that AWLA can achieve lower CO2 emissions and shorter travel time compared to CSH with static segment settings.

  • 462.
    Yang, Mingkun
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Savas, Suleyman
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Ul-Abdin, Zain
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    A Communication Library for Mapping Dataflow Applications on Manycore Architectures2013Inngår i: Proceedings of the 6th Swedish Multicore Computing Workshop / [ed] Tomas Nordstrom & Zain-ul-Abdin, 2013, s. 65-68Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Dataflow programming is a promising paradigm for high performance embedded parallel computing. When mapping a dataflow program onto a manycore architecture a key component is the library to express the communication between the actors. In this paper we present a dataflow communication library supporting the CAL actor language. A first implementation of the communication library is created for Adapteva’s manycore architecture Epiphany that contains an onchip 2-D mesh network. Three different buffering methods, with and without direct memory access (DMA) transfer, have been implemented and evaluated. We have also made a preliminary study on the effect of mapping strategies of the actors onto the cores. The assessment of the library is based on a CAL implementation of a two dimensional inverse discrete cosine transform (2D-IDCT) and our own CAL-to-C compilation framework. As expected the results show that the most efficient actor to-core mapping strategy is to keep the communication to the nearest neighbor communication pattern as much as possible. Thus, the best way to place a pipelined sequence of computations like our 2D-IDCT is to place the actors into cores in a serpentine fashion. For this application we found that the simple receiver side buffer outperforms the more complicated buffering strategies that used DMA transfer.

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  • 463.
    Yu, Rong
    et al.
    Guangdong University of Technology, Guangzhou, China.
    Ding, Jiefei
    Guangdong University of Technology, Guangzhou, China.
    Zhong, Weifeng
    Guangdong University of Technology, Guangzhou, China.
    Zhang, Yan
    Simula Research Laboratory, Fornebu, Norway.
    Gjessing, Stein
    University of Oslo, Oslo, Norway.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Price-based Energy Control for V2G Networks in the Industrial Smart Grid2015Inngår i: Proceedings of the 2015 1st International Conference on Industrial Networks and Intelligent Systems: INISCom: Tokyo, Japan: March 2-4, 2015, Piscataway, NJ: IEEE, 2015, s. 107-112, artikkel-id 7157830Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The energy crisis and global warming call for a new industrial revolution in production and distribution of renewable energy. Distributed power generation will be well developed int he new smart electricity distribution grid, in which robust power distribution will be the key technology. In this paper, we presenta new vehicle-to-grid (V2G) network for energy transfer, in which distributed renewable energy helps the power grid balance demand and supply. Plug-in hybrid electric vehicles (PHEVs) will act as transporters of electricity for distributed renewable energy dispatching. We formulate and analyze the V2G network within the theoretical framework of complex network. We also employthe generalized synchronization method to study the dynamic behavior of V2G networks. Furthermore, we develop a new price-based energy control method to stimulate the PHEV’s behavior of charging and discharging. Simulation results indicate that the V2G network can achieve synchronization and each region is able to balance energy supply and demand through price-based control. © 2015 ICST.

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  • 464.
    Yu, Rong
    et al.
    Guangdong University of Technology, Guangzhou, China.
    Huang, Xumin
    Guangdong University of Technology, Guangzhou, China.
    Kang, Jiawen
    Guangdong University of Technology, Guangzhou, China.
    Yuen, Chau
    Singapore University of Technology and Design, Singapore, Singapore.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Gjessing, Stein
    Simula Research Laboratory & Department of Informatics, University of Oslo, Oslo, Norway.
    Zhang, Yan
    Simula Research Laboratory & Department of Informatics, University of Oslo, Oslo, Norway.
    An Optimal Replenishment Strategy in Energy Harvesting Wireless Networks with A Mobile Charger2015Inngår i: 11th EAI International Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness / [ed] Der-Jiunn Deng, Lei Shu, Chih-Cheng Tseng, Chun-Cheng Lin, Neeli R. Prasad & Tony Quek, Taipei: Institute for Computer Sciences (ICST) , 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Energy harvesting wireless network is an emerging paradigm where the wireless nodes harvest energy to increase their lifetime. Due to high potential for a large variety of applications, such networks have drawn considerable attention in both industry and academia. In this paper, we consider the energy replenishment problem when the wireless nodes not only harvest energy from the ambient environment but also may receive energy from a mobile charger. We propose an optimal energy replenishment strategy using stochastic inventory theory to derive the optimal amount of energy supplied by the mobile charger. The simulation results show that our proposed scheme not only optimizes the energy utilization, but also improves the economic benefit of the wireless nodes. Copyright © 2015–2015 ICST

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  • 465.
    Yu, Tianyi
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Edén, Jenny
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Englund, Cristofer
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Viktoria Swedish ICT, Gothenburg, Sweden.
    Larsson, Tony
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Traffic Situation Estimator for Adaptive Cruise Control2016Inngår i: 2016 IEEE 17th International Symposium on A World of Wireless, Mobile and Multimedia Networks (WoWMoM), Piscataway, NJ: IEEE, 2016, artikkel-id 7523567Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A traffic situation estimator capable of analyzing driving behavior utilizing an image analysis-based tracking module is presented. The behavior is analyzed by using a state machine driven counter to estimate the traffic rhythm and determine if the detected vehicles are approaching, getting away, have been overtaken or have overtaken the ego-vehicle. Depending on the result, the traffic situation estimator suggest different reactions, either to drive faster, slower or optionally suggest to overtake vehicles ahead to help the driver to follow the traffic rhythm which in turn will improve safety and energy efficiency. The proposed approach is implemented in a smart-phone and has shown good performance while testing the application on a two-lane highway. © 2016 IEEE.

  • 466.
    Zain-ul-Abdin,
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Åhlander, Anders
    Business Area Electronic Defence Systems, Saab AB, Gothenburg, Sweden.
    Svensson, Bertil
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Programming Real-time Autofocus on a Massively Parallel Reconfigurable Architecture using Occam-pi2011Inngår i: Proceedings of the 19th Annual IEEE International Symposium on Field-Programmable Custom Computing Machines (FCCM'2011), Los Alamitos, Calif.: IEEE Computer Society, 2011, s. 194-201Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recently we proposed occam-pi as a high-level language for programming massively parallel reconfigurable architectures. The design of occam-pi incorporates ideas from CSP and pi-calculus to facilitate expressing parallelism and reconfigurability. The feasability of this approach was illustratedby building three occam-pi implementations of DCT executing on an Ambric. However, because DCT is a simple and well studied algorithm it remained uncertain whether occam-pi would also be effective for programming novel, more complex algorithms.

    In this paper, we demonstrate the applicability of occam-pi for expressing various degrees of parallelism by implementinga significantly large case-study of focus criterion calculation inan autofocus algorithm on the Ambric architecture. Autofocus is a key component of synthetic aperture radar systems. Two implementations of focus criterion calculation were developedand evaluated on the basis of performance. The comparison of the performance results with a single threaded software implementation of the same algorithm show that the throughput of the two implementations are 11x and 23x higher than the sequential implementation despite a much lower (9x) clock frequency. The two designs are, respectively, 29x and 40x moreenergy efficient.

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  • 467.
    Zeng, Yingfu
    et al.
    Rice University, TX, United States.
    Bartha, Ferenc
    Rice University, TX, United States.
    Taha, Walid
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Compile-Time Extensions to Hybrid ODEs2017Inngår i: Electronic Proceedings in Theoretical Computer Science, ISSN 2075-2180, E-ISSN 2075-2180, s. 52-70Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reachability analysis for hybrid systems is an active area of development and has resulted in many promising prototype tools. Most of these tools allow users to express hybrid system as automata with a set of ordinary differential equations (ODEs) associated with each state, as well as rules for transitions between states. Significant effort goes into developing and verifying and correctly implementing those tools. As such, it is desirable to expand the scope of applicability tools of such as far as possible. With this goal, we show how compile-time transformations can be used to extend the basic hybrid ODE formalism traditionally supported in hybrid reachability tools such as SpaceEx or Flow*. The extension supports certain types of partial derivatives and equational constraints. These extensions allow users to express, among other things, the Euler-Lagrangian equation, and to capture practically relevant constraints that arise naturally in mechanical systems. Achieving this level of expressiveness requires using a binding time-analysis (BTA), program differentiation, symbolic Gaussian elimination, and abstract interpretation using interval analysis. Except for BTA, the other components are either readily available or can be easily added to most reachability tools. The paper therefore focuses on presenting both the declarative and algorithmic specifications for the BTA phase, and establishes the soundness of the algorithmic specifications with respect to the declarative one.

  • 468.
    Zeng, Yingfu
    et al.
    Rice University, Houston, USA.
    Chad, Rose
    Rice University, Houston, USA.
    Taha, Walid
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Rice University, Houston, USA.
    Duracz, Adam
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Atkinson, Kevin
    Rice University, Houston, USA.
    Philippsen, Roland
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Cartwright, Robert
    Rice University, Houston, USA.
    O'Malley, Marcia
    Rice University, Houston, USA.
    Modeling Electromechanical Aspects of Cyber-Physical Systems2016Inngår i: Journal of Software Engineering for Robotics, ISSN 2035-3928, E-ISSN 2035-3928, Vol. 7, nr 1, s. 100-119Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Model-based tools have the potential to significantly improve the process of developing novel cyber-physical systems (CPS). In this paper, we consider the question of what language features are needed to model such systems. We use a small, experimental hybrid systems modeling language to show how a number of basic and pervasive aspects of cyber-physical systems can be modeled concisely using the small set of language constructs. We then consider four, more complex, case studies from the domain of robotics. The first, a quadcopter, illustrates that these constructs can support the modeling of interesting systems. The second, a serial robot, provides a concrete example of why it is important to support static partial derivatives, namely, that it significantly improves the way models of rigid body dynamics can be expressed. The third, a linear solenoid actuator, illustrates the language’s ability to integrate multiphysics subsystems. The fourth and final, a compass gait biped, shows how a hybrid system with non-trivial dynamics is modeled. Through this analysis, the work establishes a strong connection between the engineering needs of the CPS domain and the language features that can address these needs. The study builds the case for why modeling languages can be improved by integrating several features, most notably, partial derivatives, differentiation without duplication, and support for equations. These features do not appear to be addressed in a satisfactory manner in mainstream modeling and simulation tools.

    Fulltekst (pdf)
    fulltext
  • 469.
    Zeng, Yingfu
    et al.
    Rice University, Houston, USA.
    Rose, Chad
    Rice University, Houston, USA.
    Brauner, Paul
    Rice University, Houston, USA.
    Taha, Walid
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Rice University, Houston, USA.
    Masood, Jawad
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Philippsen, Roland
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    O’Malley, Marcia
    Rice University, Houston, USA.
    Cartwright, Robert
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS). Rice University, Houston, USA.
    Modeling Basic Aspects of Cyber-Physical Systems, Part II2013Inngår i: Proceedings DSLRob 2013 / [ed] Christian Schlegel, Ulrik Pagh Schultz, Serge Stinckwich, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We consider the question of what language features are needed to effectively model cyber-physical systems (CPS). In previous work, we proposed a core language called Acumen as a way to study this question, and showed how several basic aspects of CPS can be modeled clearly in a language with a small set of constructs. This paper reports on the result of our analysis of two more complex case studies from the domain of rigid body dynamics. The first one, a quadcopter, illustrates that Acumen can support larger, more interesting systems than previously shown. The second one, a serial robot, provides a concrete example of why explicit support for static partial derivatives can significantly improve the expressivity of a CPS modeling language.

  • 470.
    Zeng, Yingfu
    et al.
    Rice University, Houston, TX, USA.
    Rose, Chad
    Rice University, Houston, TX, USA.
    Brauner, Paul
    Rice University, Houston, TX, USA.
    Taha, Walid
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Rice University, Houston, TX, USA.
    Masood, Jawad
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Philippsen, Roland
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    O'Malley, Marcia
    Rice University, Houston, TX, USA.
    Cartwright, Robert
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). Rice University, Houston, TX, USA.
    Modeling Basic Aspects of Cyber-Physical Systems, Part II (Extended Abstract)2014Inngår i: 2014 IEEE International Conference on High Performance Computing and Communications, 2014 IEEE 6th International Symposium on Cyberspace Safety and Security, 2014 IEEE 11th International Conference on Embedded Software and Systems (HPCC, CSS, ICESS) / [ed] Randall Bilof, Piscataway, NJ: IEEE Computer Society, 2014, s. 550-557Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We continue to consider the question of what language features are needed to effectively model cyber-physical systems (CPS). In previous work, we proposed using a core language as a way to study this question, and showed how several basic aspects of CPS can be modeled clearly in a language with a small set of constructs. This paper reports on the result of our analysis of two, more complex, case studies from the domain of rigid body dynamics. The first one, a quadcopter, illustrates that previously proposed core language can support larger, more interesting systems than previously shown. The second one, a serial robot, provides a concrete example of why we should add language support for static partial derivatives, namely that it would significantly improve the way models of rigid body dynamics can be expressed. © 2014 IEEE.

  • 471.
    Zhang, Hequn
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Wang, Rui
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Larsson, Tony
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Simulation of Region-based Geocast Routing Protocols2014Inngår i: 2014 International Conference on Connected Vehicles and Expo (ICCVE), Piscataway, NJ: IEEE Press, 2014, s. 723-730, artikkel-id 7297645Konferansepaper (Fagfellevurdert)
    Abstract [en]

    As one of the most important enablers of Intelligent Transportation System (ITS), Inter-Vehicle Communication (IVC) have been a hot research direction in nearly a decade. To improve vehicle safety and cooperative systems, most of ITS applications need efficient and stable Vehicular Ad hoc Networks (VANETs) among vehicles and infrastructures, which can be set up by Geocast routing protocols. Some of these applications require the protocols, known as region-based Geocast routing protocols, supporting to broadcast messages to vehicles within a specific geographic region. Since different protocols are appropriate for different purposes or occasions, it is significant to simulate protocols and evaluate their performances under a variety of scenarios. Therefore, this paper focuses on investigations of simulation environment configurations for some known Geocast routing protocols. According to the investigations, a region based Geocast routing simulator is designed and developed. To demonstrate the effectiveness and the reliability of this simulator, several protocols are simulated and the performances of them are presented. © 2014 IEEE

  • 472.
    Zhang, Ke
    et al.
    University of Electronic Science and Technology of China, Chengdu, China.
    Mao, Yuming
    University of Electronic Science and Technology of China, Chengdu, China.
    Leng, Supeng
    University of Electronic Science and Technology of China, Chengdu, China.
    Maharjan, Sabita
    Simula Research Laboratory, Fornebu, Norway & University of Oslo, Oslo, Norway.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Zhang, Yan
    University of Oslo, Oslo, Norway.
    Contract-theoretic Approach for Delay Constrained Offloading in Vehicular Edge Computing Networks2019Inngår i: Mobile Networks and Applications , ISSN 1383-469X, E-ISSN 1572-8153, Vol. 24, nr 3, s. 1003-1014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mobile Edge Computing (MEC) is a promising solution to improve vehicular services through offloading computation to cloud servers in close proximity to mobile vehicles. However, the self-interested nature together with the high mobility characteristic of the vehicles make the design of the computation offloading scheme a significant challenge. In this paper, we propose a new Vehicular Edge Computing (VEC) framework to model the computation offloading process of the mobile vehicles running on a bidirectional road. Based on this framework, we adopt a contract theoretic approach to design optimal offloading strategies for the VEC service provider, which maximize the revenue of the provider while enhancing the utilities of the vehicles. To further improve the utilization of the computing resources of the VEC servers, we incorporate task priority distinction as well as additional resource providing into the design of the offloading scheme, and propose an efficient VEC server selection and computing resource allocation algorithm. Numerical results indicate that our proposed schemes greatly enhance the revenue of the VEC provider, and concurrently improve the utilization of cloud computing resources. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

  • 473.
    Zhang, Ke
    et al.
    University of Electronic Science and Technology of China, Chengdu, China.
    Mao, Yuming
    University of Electronic Science and Technology of China, Chengdu, China.
    Leng, Supeng
    University of Electronic Science and Technology of China, Chengdu, China.
    Maharjan, Sabita
    Simula Research Laboratory, Oslo, Norway.
    Zhang, Yan
    Simula Research Laboratory, Oslo, Norway.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Incentive-Driven Energy Trading in the Smart Grid2016Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 4, s. 1243-1257, artikkel-id 7436757Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The smart grid is widely considered as an efficient and intelligent power system. With the aid of communication technologies, the smart grid can enhance the efficiency and reliability of the grid system through intelligent energy management. However, with the development of new energy sources, storage and transmission technologies together with the heterogeneous architecture of the grid network, several new features have been incorporated into the smart grid. These features make the energy trading more complex and pose a significant challenge on designing efficient trading schemes. Based on this motivation, in this paper, we present a comprehensive review of several typical economic incentive approaches adopted in the energy-trading control mechanisms. We focus on the technologies that address the challenges specific to the new features of the smart grid. Furthermore, we investigate the energy trading in a new cloud-based vehicle-to-vehicle energy exchange scenario. We propose an optimal contract-based electricity trading scheme, which efficiently increases the generated profit. © 2013 IEEE.

    Fulltekst (pdf)
    fulltext
  • 474.
    Zhang, Ke
    et al.
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Mao, Yuming
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Leng, Supeng
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Zhang, Yan
    Simula Research Laboratory, Oslo, Norway.
    Delay constrained offloading for Mobile Edge Computing in cloud-enabled vehicular networks2016Inngår i: Proceedings of 2016 8th International Workshop on Resilient Networks Design and Modeling (RNDM) / [ed] Magnus Jonsson, Jacek Rak, Arun Somani, Dimitri Papadimitriou & Alexey Vinel, Piscataway: IEEE Press, 2016, s. 288-294Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cloud-based vehicular networks is a new paradigm to improve the vehicular services through distributing computation tasks between remote clouds and local vehicular terminals. To further reduce the latency and the transmission cost of the computation offloading, we propose a cloud-based Mobile Edge Computing (MEC) offloading framework in vehicular networks. In the framework, efficient computation offloading strategies are designed through a contract theoretic approach. We obtain the optimal feasible contracts that maximize the benefit of the MEC service provider while enhancing the utilities of the vehicles. Furthermore, considering the resource limitation of the MEC server and the latency tolerance of the computation tasks, we propose a contract-based computation resource allocation scheme. Numerical results show that our proposed scheme greatly enhances the utility of the MEC service provider. ©2016 IEEE 

  • 475.
    Zhang, Ke
    et al.
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Mao, Yuming
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Leng, Supeng
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Zeng, Ming
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Xu, Liang
    School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, China.
    Jiang, Li
    Beijing University of Posts and Telecommunications, Beijing, China.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Optimal energy exchange schemes in smart grid networks: A contract theoretic approach2016Inngår i: 2016 IEEE/CIC International Conference on Communications in China (ICCC), Piscataway, NJ: IEEE, 2016, artikkel-id 7636834Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Vehicle-to-Grid (V2G) is a promising paradigm to alleviate energy supply and demand imbalance of the grid. To further improve the power transmission efficiency, in this paper, we propose a cloudlet-based Vehicle-to-Vehicle (V2V) energy exchange framework. In the framework, the Energy Switch Center (ESC) serves as a trading broker, which purchases electricity from discharging vehicles and then resells it to the charging ones without energy transmission on the grid. The energy trading process is modeled in a contract theoretic approach. We derive the optimal feasible contracts which maximize the profit of the ESC. Furthermore, we systematically study the practical scenario where both the charging demand and renewable energy supplement are random variables, and propose a practical optimal contract-based electricity purchase scheme. Simulation results show that the proposed scheme can efficiently increase the profit of the ESC than the other mechanisms. © 2016 IEEE.

  • 476.
    Zhang, Yan
    et al.
    Department of Informatics, University of Oslo, Oslo, Norway.
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Li, Minqiang
    Department of Information Management and Management Science, Tianjin University, Tianjin, China.
    Guest editorial special issue on industrial IoT systems and applications2017Inngår i: IEEE Systems Journal, ISSN 1932-8184, E-ISSN 1937-9234, Vol. 11, nr 3, s. 1337-1339, artikkel-id 8052330Artikkel i tidsskrift (Annet vitenskapelig)
  • 477.
    Zhang, Yan
    et al.
    School of Electrical and Electronics Engineering, Nanyang Technological University, Singapore, Singapore.
    Jonsson, MagnusHögskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).Li, MinqiangDepartment of Information Management and Management Science, College of Management and Economics, Tianjin University, Tianjin Shi, China.
    Special Issue on Industrial IoT Systems and Applications2017Collection/Antologi (Fagfellevurdert)
  • 478.
    Zheyuan, Liu
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Evaluation of platoon Application Enabled by Contemporary ETSI ITS-G5 Standards2015Independent thesis Advanced level (degree of Master (Two Years)), 80 poäng / 120 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 479.
    Zhuang, Weihua
    et al.
    University of Waterloo, Ontario, Canada.
    Jamalipour, Abbas
    University of Sydney, Sydney, New South Wales, Australia.
    Bai, Fan
    Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Emerging Technologies, Applications, and Standardizations for Connecting Vehicles: [From the Guest Editors]2015Inngår i: IEEE Vehicular Technology Magazine, ISSN 1556-6072, E-ISSN 1556-6080, Vol. 10, nr 4, s. 33-35Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The articles in this special section focus on the state of the art in the emerging technology for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications, the latest development in standardizations and regulations, and potential services and applications for vehicles on roads. © Copyright 2015 IEEE

  • 480.
    Zhuang, Weihua
    et al.
    Department of Electrical and Computer Engineering, University of Waterloo, ON, Canada.
    Jamalipour, Abbas
    University of Sydney, Sidney, Australia.
    Bai, Fan
    Caign, Universitarnegie Mellon University, University of Illinois at Urbana-Champy of Southern California, United States.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Emerging Technologies, Applications, and Standardizations for Connecting Vehicles (Part II)2017Inngår i: IEEE Vehicular Technology Magazine, ISSN 1556-6072, E-ISSN 1556-6080, Vol. 12, nr 2, s. 23-25Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 481.
    Åhlander, Anders
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Efficient parallell architectures for future radar signal processing2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The processing demands on future embedded radar signal processors may stretch to several trillions of floating-point operations per second (TFLOPS). This is an increase of two to three orders of magnitude realtive to the requirements of today. Still, the tight size and power constraints are unchanged. To meet this, new, highly parallel computer systems are needed. The systems should efficiently deliver very high performance as well as being general enough. Another challenge for future signal processors is the requirement for having huge working memories that are accessed in complicated patterns.

    This thesis analyses the challenges of two classes of radar signal processing applications, namely Space-Time Adaptive Processing (STAP), which represents performance-intensive applications, and Synthetic Aperture Radar (SAR) processing, which represents memory-intensive applications. In addition to the actual performance and memory aspects of the applications, the desire for low-effort application development and maintenance is taken into consideration.

    A multiple SIMD architecture is proposed for the STAP calculations. This architecture gives a combination of the high computational density in the SIMD processing modules with the overall flexibility provided on the system level. An embedded signal processing system based on the architecture is shown to be capable of TFLOPS class performance using standard CMOS VLSI technology available in the year 2001. The system is, for the given application domain, considered to have the same generality as commercial off-the-shelf (COTS) hardware, but has several years of time lead over COTS with regard to the computational performance.

    The studied SAR processing is characterized by operating on huge data sets and having varying, non-linear data access paths. For this, algorithm solutions and execution schemes in inerplay with a system parallelization approach are proposed. It is shown that it is possible to obtain efficient memory accesses, despite the omplicated memory access patterns. It is also shown that the computational burden from complex interpolation kernels can be reduced through extensive calculation reuse.

    Efficient engineering of complex applications in this context is discussed. The use of semi-transparent, platform-based development is demonstrated for STAP and SAR, and advocated for obtaining high engineering defficiency and long system sustainability, as well as high performance efficiency.

    The overall conclusion drawn from this work is that a solid knowledge of the application domain and its future requirements, in combination with an understanding of its interaction with computational architectures, potentially enables several years of lead time in the realization of new, advanced signal prodcessing products. The important requirements on programmability and sustainability must also be taken into account in order to achieve a viable signal processing solution.

  • 482.
    Åhlander, Anders
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Hellsten, H.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Lind, K.
    Saab Microwave Systems, Gothenburg, Sweden.
    Lindgren, J.
    Saab Microwave Systems, Gothenburg, Sweden.
    Svensson, Bertil
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Architectural challenges in memory-intensive, real-time image forming2007Inngår i: International Conference on Parallel Processing, 2007. ICPP 2007 / [ed] Li Jiandong, IEEE Press, 2007, s. 35-45Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The real-time image forming in future, high-end synthetic aperture radar systems is an example of an application that puts new demands on computer architectures. The initial question is whether it is at all possible to meet the demands with state-of-the-art technology or foreseeable new technology. It is therefore crucial to understand the computational flow, with its associated memory, bandwidth and processing demands. In this paper we analyse the application in order to, primarily, understand the algorithms and identify the challenges they present on a basic architectural level. The processing in the radar system is characterized by working on huge data sets, having complex memory access patterns, and doing real-time compensations for flight path errors. We propose algorithm solutions and execution schemes in interplay with a two-level (coarse-grain/fine-grain) system parallelization approach, and we provide approximate models on which the demands are quantified. In particular, we consider the choice of method for the performance-intensive data interpolations. This choice presents a trade-off problem between computational performance and size of working memory. The results of this "upstream" study will serve as a basis for further, more detailed architecture studies.

    Fulltekst (pdf)
    FULLTEXT01
  • 483.
    Åhlander, Anders
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Åström, Anders
    Airborne Radar Division, Ericsson Microwave Systems AB, Mölndal, Sweden.
    Svensson, Bertil
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Taveniku, Mikael
    XCube Communication, Westford, MA, USA.
    Meeting Engineer Efficiency Requirements in Highly Parallel Signal Processing by Using Platforms2005Inngår i: Proceedings of the 17th IASTED International Conference on Parallel and Distributed Computing and Systems: November 14-16, 2005, Phoenix, AZ, USA / [ed] S. Q. Zheng, Anaheim: ACTA Press, 2005, s. 693-700Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    One of the driving forces behind the development of new, highly parallel architectures is the need for embedded high-performance computing. The development of advanced applications on such architectures is, however, potentially connected to high costs. Cost-effective devel opment requires tools and processes that provide engineer efficiency, in this case tools and processes that help the developer master the application complexity. Related to engineer efficiency are the important concepts of system sustainability and flexibility. To address these issues, a platform approach can be taken. The platform should offer an understandable and stable development model, and at the same time give the possibility to take advantage of the rapid technology development, including the use of new parallel architectures. Thus it must support multiple hard ware targets, and the development model should decouple application development from mapping aspects. Two radar signal processing examples, one compute-intensive STAP and one data-intensive SAR, are used to illustrate the need. The GEPARD platform is presented as an example of our approach, and we argue that the described platform is a good fit for advanced signal processing development, facilitating the desired engineer efficiency, sustainability, and flexibility.

  • 484.
    Jonsson, Magnus ()
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Widén, Kristian ()
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL), Sustainability, Innovation and Management in Building (SIMB).
    Profile Area Smart Cities and Communities: 2019 Annual Report2020Annet (Annet (populærvitenskap, debatt, mm))
    Fulltekst (pdf)
    fulltext
78910 451 - 484 of 484
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