285 research outputs found

    Special cases of online parallel job scheduling

    Get PDF
    In this paper we consider the online scheduling of jobs, which require processing on a number of machines simultaneously. These jobs are presented to a decision maker one by one, where the next job becomes known as soon as the current job is scheduled. The objective is to minimize the makespan. For the problem with three machines we give a 2.8-competitive algorithm, improving upon the 3-competitive greedy algorithm. For the special case with arbitrary number of machines, where the jobs appear in non-increasing order of machine requirement, we give a 2.4815-competitive algorithm, improving the 2.75-competitive greedy algorithm

    Run-time adaptation of a reconfigurable mobile UMTS receiver

    Get PDF
    UMTS receivers are mobile devices, which should have a low energy consumption and operates in a frequently changing environment. The idea of this paper is to adapt the amount of signal processing for the reception within an UMTS mobile to this changing environment. In this way the amount of signal processing can be decreased for a good channel to decrease the energy consumption and for a bad channel the signal processing can be increased to guarantee a minimum Quality of Service for the signal. Due to space limitation, this paper only describes the approach. For full details see [1]

    Run-time Mapping of Applications to a Heterogeneous SoC

    Get PDF
    This paper presents an iterative hierarchical approach to map an application to a parallel heterogeneous SoC architecture at run-time. The application is modeled as a set of communicating processes. The optimization objective is to minimize the energy consumption of the SoC, while still providing the required Quality of Service. This approach is flexible, scalable and the performance looks promisin

    BER estimation for wireless links using BPSK/QPSK modulation

    Get PDF
    This paper introduces a method that computes an estimation of the bit error rate (BER) based on the RAKE receiver soft output only. For this method no knowledge is needed about the channel characteristics nor the precise external conditions. Simulations show that the mean error of the estimation is below 2%, with only a small variance. Also an estimation of the BER for a different spreading factor or a different number of RAKE finger can be made. Implementation issues for a practical use of the method are discussed

    Energy-efficient wireless communication for mobile multimedia terminals

    Get PDF
    This paper presents a control system that adapts a WCDMA receiver at run-time to minimize the energy consumption while providing an adequate Quality of Service (QoS). The adaptation is done at run-time, because of the dynamic environment of a mobile receiver. Simulations show that run-time adaptation to the environment decreases the energy consumption of a receiver and also improves other QoS parameters, such as a higher throughput and a lower frame error rate

    Algorithms for balancing demand-side load and micro-generation in Islanded Operation

    Get PDF
    Micro-generators are devices installed in houses pro-\ud ducing electricity at kilowatt level. These appliances can\ud increase energy efficiency significantly, especially when\ud their runtime is optimized. During power outages micro-\ud generators can supply critical systems and decrease dis-\ud comfort.\ud In this paper a model of the domestic electricity infras-\ud tructure of a house is derived and first versions of algo-\ud rithms for load/generation balancing during a power cut\ud are developed. In this context a microCHP device, produc-\ud ing heat and electricity at the same time with a high effi-\ud ciency, is used as micro-generator.\ud The model and the algorithms are incorporated in a sim-\ud ulator, which is used to study the effect of the algorithms for\ud load/generation balancing. The results show that with some\ud extra hardware all appliances in a house can be supplied,\ud however not always at the preferred time.\u

    BER estimation for HiperLAN/2

    Get PDF
    This paper presents a method to estimate the bit error rate (BER) of the wireless channel based on statistical analysis of the soft output of the receiver only. In HiperLAN/2 several modulation schemes can be used. The system should select the most suitable modulation scheme dependent on the quality of the wireless link and the Quality of Service requirements of the user. Our BER estimation method can be used to estimate the current quality of the wireless link and the quality when another modulation mode is considered. With this information, it is possible to select the most suitable modulation scheme for the current situation

    Clustering clinical departments for wards to achieve a prespecified blocking probability

    Get PDF
    When the number of available beds in a hospital is limited and fixed, it can be beneficial to cluster several clinical departments such that the probability of not being able to admit a patient is acceptably small. The clusters are then assigned to the available wards such that enough beds are available to guarantee a blocking probability below a prespecified value. We first give an exact formulation of the problem to be able to achieve optimal solutions. To reduce computation times, we also introduce two heuristic solution methods. The first heuristic is similar to the exact solution method, however, the number of beds needed is approximated by a linear function. The second heuristic uses a local search approach to determine the assignment of clinical departments to clusters and a restricted version of the exact solution method to determine the assignment of clusters to wards

    Using heat demand prediction to optimise Virtual Power Plant production capacity

    Get PDF
    In the coming decade a strong trend towards distributed electricity generation (microgeneration) is expected. Micro-generators are small appliances that generate electricity (and heat) at the kilowatt level, which allows them to be installed in households. By combining a group of micro-generators, a Virtual Power Plant can be formed. The electricity market/network requires a VPP control system to be fast, scalable and reliable. It should be able to adjust the production quickly, handle in the order of millions of micro-generators and it should ensure the required production is really produced by the fleet of microgenerators. When using micro Combined Heat and Power microgenerators, the electricity production is determined by heat demand. In this paper we propose a VPP control system design using learning systems to maximise the economical benefits of the microCHP appliances. Furthermore, ways to test our design are\ud described

    Soft output bit error rate estimation for WCDMA

    Get PDF
    This paper introduces a method that computes an estimation of the bit error rate (BER) based on the RAKE receiver soft output only. For this method no knowledge is needed about the channel characteristics nor the precise external conditions. Simulations show that the mean error of the estimation is below 2%, with only a small variance. Implementation issues for a practical use of the method are discussed
    corecore