Caching is a promising solution for the cloud radio access network (Cloud-RAN) to mitigate the traffic load problem in the fronthaul links. Multiuser downlink beamforming plays an important role in efficient utilisati...
详细信息
Caching is a promising solution for the cloud radio access network (Cloud-RAN) to mitigate the traffic load problem in the fronthaul links. Multiuser downlink beamforming plays an important role in efficient utilisation of spectrum and transmission power while satisfying the user's quality of service requirements. When the number of users exceeds the serving capacity of the network, certain users will have to be dropped or rescheduled. This is normally achieved by appropriate admission control mechanisms. Introducing local storage or cache at the remote radio heads where some popular contents are cached, the authors propose beamforming and admission control techniques for cache-enabled Cloud-RAN in the downlink. This minimises the total network cost including power and fronthaul cost while admitting as many users as possible. They formulate this multi-objectiveoptimisationproblem as a single objective optimisation problem. The original problem, which is a mixed-integer non-linear programme, is first converted to the mixed-integer second-order cone programming form. The branch and bound algorithm is then used to determine the optimal and suboptimal solutions. A simulation study has been conducted to assess the performance of both methods.
This study proposes a novel methodology that employs fuzzified binary real coded artificial bee colony (ABC) algorithm for solving multi-objective unit commitment problem. On solving unit commitment problem, the propo...
详细信息
This study proposes a novel methodology that employs fuzzified binary real coded artificial bee colony (ABC) algorithm for solving multi-objective unit commitment problem. On solving unit commitment problem, the proposed binary coded ABC algorithm finds the ON/OFF status of the generating units whereas the economic dispatch is solved using the real coded ABC. Here, three conflicting functions such as fuel cost, emission and reliability level of the system are considered. These functions are formulated as a single objective optimisation problem using the fuzzy set theory. Also, the fuzzy membership design variables are tuned using real coded ABC thereby requirement of expertise for setting these variables are eliminated. The proposed method is validated on six unit system, IEEE 30 bus system, ten unit system, 40 unit system and IEEE RTS 24 bus system. The effectiveness of the proposed technique is demonstrated by comparing its performance with other methods reported in the literature.
This study proposes a multi-stage restoration strategy to solve the service restoration problem in distribution systems considering the uncertainty of outage duration. Furthermore, it also proposes a restoration index...
详细信息
This study proposes a multi-stage restoration strategy to solve the service restoration problem in distribution systems considering the uncertainty of outage duration. Furthermore, it also proposes a restoration index defined in terms of (i) priority of the load restored, (ii) number of switching operations, and (iii) estimated likelihood of the restoration solution to assist the utility in enhanced decision-making. Service restoration is formulated as a single objective optimisation problem considering the maximising of the restoration index as the only objective. A decentralised multi-agent system method is developed to solve the service restoration problem considering controlled islanding of distributed generators. The uncertainty of outage duration is estimated using the maximum entropy principle-based on the cause of the fault. Exhaustive case studies are implemented on a small 38 bus and a large 119 bus test distribution system to demonstrate the effectiveness of the proposed multi-stage restoration strategy to restore the system under outage duration uncertainty.
暂无评论