In a frequency-division multiple access satellite communication (SATCOM) system, how to effectively reduce the non-linearity of high-power amplifier to improve the transponder power utility and system capacity, which ...
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In a frequency-division multiple access satellite communication (SATCOM) system, how to effectively reduce the non-linearity of high-power amplifier to improve the transponder power utility and system capacity, which is the key goal of link supportability analysis, is a challenging and essential step in system design. In this study, the authors creatively model the link supportability analysis problem as a min-max optimisation for a digital channelised SATCOM system, and propose an effective variableneighbourhoodsearch (VNS) algorithm for the established optimisation. By minimising the maximum of carrier powers output from the satellite transponder, the established min-max optimisation model aims at reducing the difference among carrier powers in the satellite transponder as much as possible to avoid carrier power being irregular so that the authors can optimally set the transponder's operating point to improve the transponder power utility, and minimise each terminal's uplink effective isotropic radiated power (EIRP) so that as many links as possible could be supported in the system and thus the system capacity could be enhanced. Practical examples are also presented to verify the proposed approach's superior performance in improving a digital channelised SATCOM system's transponder power utility and the system capacity.
In this paper, a two-level algorithm is proposed to solve the distribution network reconfiguration with an objective of minimum power loss. In the first level reconfiguration, switches of maximum power loss reduction ...
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In this paper, a two-level algorithm is proposed to solve the distribution network reconfiguration with an objective of minimum power loss. In the first level reconfiguration, switches of maximum power loss reduction are disconnected by the branch exchange (BE) algorithm. Based on the results, neighbourhoods of disconnected switches are constructed by the deterministic transform method in the second level. The variableneighbourhoodsearch (VNS) algorithm keeps searching the neighbourhoods to obtain a better solution with a lower power loss. Simulations are carried out on IEEE33 and PG&69 distribution networks to verify the superiority of the proposed algorithm. The obtained results are compared with the other methods available in the paper. It can be concluded that the presented method has both high stability and rapidity.
The efficient operation of container ports relies on the coordination of operational problems including berth allocation and container internal transportation routing. Yard layout designs with diagonal cross lanes may...
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The efficient operation of container ports relies on the coordination of operational problems including berth allocation and container internal transportation routing. Yard layout designs with diagonal cross lanes may bring more opportunities for future container terminals, and this opportunity requires further evaluation of operational performance improvements. This study analyses the application possibility of flying-V layout and fishbone layout in container yards by investigating the berth and yard scheduling problem. In detail, we introduce the two layouts first, and model the berth and yard scheduling problem as a mixed-integer linear programming model. The model optimizes performance indicators including travel distance and berthing delay. We develop a neighbourhoodsearchalgorithm to solve the problem and verify the effectiveness and efficiency by numerical experiments. The proposed model and algorithm provide a framework for the evaluation of yard layouts. Sensitivity analysis reveals the relationship between the angle of diagonal cross lanes and total travel distance and discusses the influence of the width-depth ratio. The comparative experiments investigate different performance indicators and show that the diagonal yard layouts have proven to be efficient.
The real time characteristic is a critical property of cyber-physical systems and the transmission tardiness introduced by the computer system can lead to a significant performance degradation. In order to improve the...
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The real time characteristic is a critical property of cyber-physical systems and the transmission tardiness introduced by the computer system can lead to a significant performance degradation. In order to improve the real-time performance, data aggregation is always employed during data transmission. This paper studies a hybrid two-stage batch scheduling problem in which a set of receiving sensors are assigned to collect the data at the first stage and an aggregation sensor is employed to receive the data from receiving sensors, fuse and transmit the data to the destination at the second stage. Two objectives, which are minimising the number of tardy tasks and the total transmission tardiness, are studied. Some analytical properties are proved and some algorithms are proposed to solve the problem. Extensive numerical experiments are conducted to test the performances of the proposed algorithms.
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