传统的货位优化方法没有充分利用库存量单位(Stock keeping units,SKUs)之间的相关性关系。以一种存在相关性需求的'波次分区拣货、整体补货'的周期性环境为对象,以最小化最大的分区拣货时间为目标建立货位优化的数学模型,提出...传统的货位优化方法没有充分利用库存量单位(Stock keeping units,SKUs)之间的相关性关系。以一种存在相关性需求的'波次分区拣货、整体补货'的周期性环境为对象,以最小化最大的分区拣货时间为目标建立货位优化的数学模型,提出相关性强度的概念和计算方法,设计出基于相关性的货位指派算法(Storage allocation based on correlations,SABC)和不考虑相关性的随机货位指派算法(Storage allocation based on random,SABR)算法,SABC算法以体积—订单指数(Cube per order index,COI)法则的解为初始解,通过定量化的'相关性位置交换策略'将相关性强的'SKUs对'指派到相近的货位中来提高拣货效率。测试结果表明:SABC算法具有较好的收敛性,其收敛速度明显优于SABR算法,求解质量比COI法平均改进约7.6%～25.1%,比SABR算法平均改进约1.36%～14.50%;需求相关性强度越高,拣货效率提升潜力越大。展开更多
Pure position permutation image encryption algorithms, commonly used as image encryption investigated in this work are unfortunately frail under known-text attack. In view of the weakness of pure position permutation ...Pure position permutation image encryption algorithms, commonly used as image encryption investigated in this work are unfortunately frail under known-text attack. In view of the weakness of pure position permutation algorithm,we put forward an effective decryption algorithm for all pure-position permutation algorithms. First, a summary of the pure position permutation image encryption algorithms is given by introducing the concept of ergodic matrices. Then, by using probability theory and algebraic principles, the decryption probability of pure-position permutation algorithms is verified theoretically; and then, by defining the operation system of fuzzy ergodic matrices, we improve a specific decryption al-gorithm. Finally, some simulation results are shown.展开更多
文摘传统的货位优化方法没有充分利用库存量单位(Stock keeping units,SKUs)之间的相关性关系。以一种存在相关性需求的'波次分区拣货、整体补货'的周期性环境为对象,以最小化最大的分区拣货时间为目标建立货位优化的数学模型,提出相关性强度的概念和计算方法,设计出基于相关性的货位指派算法(Storage allocation based on correlations,SABC)和不考虑相关性的随机货位指派算法(Storage allocation based on random,SABR)算法,SABC算法以体积—订单指数(Cube per order index,COI)法则的解为初始解,通过定量化的'相关性位置交换策略'将相关性强的'SKUs对'指派到相近的货位中来提高拣货效率。测试结果表明:SABC算法具有较好的收敛性,其收敛速度明显优于SABR算法,求解质量比COI法平均改进约7.6%～25.1%,比SABR算法平均改进约1.36%～14.50%;需求相关性强度越高,拣货效率提升潜力越大。
基金Project supported by the National Natural Science Foundation
of China (Nos. 60302012+2 种基金 60202002) and the Youth Scientific
Research Foundation of Ningbo (No. 2003A61006) China
文摘Pure position permutation image encryption algorithms, commonly used as image encryption investigated in this work are unfortunately frail under known-text attack. In view of the weakness of pure position permutation algorithm,we put forward an effective decryption algorithm for all pure-position permutation algorithms. First, a summary of the pure position permutation image encryption algorithms is given by introducing the concept of ergodic matrices. Then, by using probability theory and algebraic principles, the decryption probability of pure-position permutation algorithms is verified theoretically; and then, by defining the operation system of fuzzy ergodic matrices, we improve a specific decryption al-gorithm. Finally, some simulation results are shown.
