A DMVOCC-MVDA （distributed multiversion optimistic concurrency control with multiversion dynamic adjustment） protocol was presented to process mobile distributed real-time transaction in mobile broadcast environment...A DMVOCC-MVDA （distributed multiversion optimistic concurrency control with multiversion dynamic adjustment） protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load （think time is ls） the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols.展开更多
随着高比例、大规模分布式光伏并网以及电动汽车的普及,如何发挥电动汽车灵活性、实现配电网分布式光伏与本地电动汽车负荷灵活性资源的友好协调是当前需要解决的重要问题。为此,提出了考虑电动汽车与分布式光伏协同的配电网集群划分与...随着高比例、大规模分布式光伏并网以及电动汽车的普及,如何发挥电动汽车灵活性、实现配电网分布式光伏与本地电动汽车负荷灵活性资源的友好协调是当前需要解决的重要问题。为此,提出了考虑电动汽车与分布式光伏协同的配电网集群划分与运行策略。首先,建立电动汽车可调充电功率灵活性聚合模型,提出基于Louvain算法的改进模块度指标配电网分布式集群划分方法;其次,基于历史数据信息生成电动汽车多时间尺度充电场景,提出考虑电动汽车充电灵活性的分布式集群协同优化模型;最后,采用同步交替方向乘子法(synchronous alternating direction multiplier method,SADMM)实现各集群优化模型的分布式求解。仿真结果表明,利用电动汽车充电灵活性参与配电网协同运行可有效提高分布式光伏利用率,并且在满足电动汽车用户充电需求的同时保证了配电网电压运行安全。展开更多
随着电动汽车的高速发展,越来越多的电动汽车接入配电网并与配电网进行互动。针对大规模电动汽车接入配电网带来的线路重过载现象,且考虑调度大规模电动汽车对配电网调控中心产生的通信压力,提出一种基于主从博弈的电动汽车参与城市电...随着电动汽车的高速发展,越来越多的电动汽车接入配电网并与配电网进行互动。针对大规模电动汽车接入配电网带来的线路重过载现象,且考虑调度大规模电动汽车对配电网调控中心产生的通信压力,提出一种基于主从博弈的电动汽车参与城市电网分层分区调控策略。首先提出了一种基于改进分区组合性的城市配电网分区方法,将负荷相似系数以及源荷匹配系数引入到分区参数中。基于分区结果,提出了分区控制下电动汽车双层博弈调度模型,上层模型为配电网调控中心在满足精细化削峰需求约束下的自身收益最大化,并制定了与下层电动汽车聚合商的交易电价;下层模型以聚合商内电动汽车用户用电成本最低为目标,合理安排电动汽车充放电计划,两者之间形成互动博弈并达到均衡解。最后,利用同步型交替方向乘子法(synchronous alternating direction methodofmultipliers,S-ADMM)算法实现了多区域的分布式并行求解,并基于南方某市266节点配电网进行仿真计算,验证了所提模型和方法的有效性。展开更多
基金Project(20030533011)supported by the National Research Foundation for the Doctoral Program of Higher Education of China
文摘A DMVOCC-MVDA （distributed multiversion optimistic concurrency control with multiversion dynamic adjustment） protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load （think time is ls） the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols.
文摘随着高比例、大规模分布式光伏并网以及电动汽车的普及,如何发挥电动汽车灵活性、实现配电网分布式光伏与本地电动汽车负荷灵活性资源的友好协调是当前需要解决的重要问题。为此,提出了考虑电动汽车与分布式光伏协同的配电网集群划分与运行策略。首先,建立电动汽车可调充电功率灵活性聚合模型,提出基于Louvain算法的改进模块度指标配电网分布式集群划分方法;其次,基于历史数据信息生成电动汽车多时间尺度充电场景,提出考虑电动汽车充电灵活性的分布式集群协同优化模型;最后,采用同步交替方向乘子法(synchronous alternating direction multiplier method,SADMM)实现各集群优化模型的分布式求解。仿真结果表明,利用电动汽车充电灵活性参与配电网协同运行可有效提高分布式光伏利用率,并且在满足电动汽车用户充电需求的同时保证了配电网电压运行安全。
文摘随着电动汽车的高速发展,越来越多的电动汽车接入配电网并与配电网进行互动。针对大规模电动汽车接入配电网带来的线路重过载现象,且考虑调度大规模电动汽车对配电网调控中心产生的通信压力,提出一种基于主从博弈的电动汽车参与城市电网分层分区调控策略。首先提出了一种基于改进分区组合性的城市配电网分区方法,将负荷相似系数以及源荷匹配系数引入到分区参数中。基于分区结果,提出了分区控制下电动汽车双层博弈调度模型,上层模型为配电网调控中心在满足精细化削峰需求约束下的自身收益最大化,并制定了与下层电动汽车聚合商的交易电价;下层模型以聚合商内电动汽车用户用电成本最低为目标,合理安排电动汽车充放电计划,两者之间形成互动博弈并达到均衡解。最后,利用同步型交替方向乘子法(synchronous alternating direction methodofmultipliers,S-ADMM)算法实现了多区域的分布式并行求解,并基于南方某市266节点配电网进行仿真计算,验证了所提模型和方法的有效性。
