Batch picking in narrow-aisle order picking systems with consideration for picker blocking

This paper develops strategies to control picker blocking that challenge the traditional assumptions regarding the tradeoffs between wide- and narrow-aisle order picking systems. We propose an integrated batching and sequencing procedure called the indexed batching model (IBM), with the objective of minimizing the total retrieval time (the sum of travel time, pick time and congestion delays). The IBM differs from traditional batching formulations by assigning orders to indexed batches, whereby each batch corresponds to a position in the batch release sequence. We develop a mixed integer programming solution for exact control, and demonstrate a simulated annealing procedure to solve large practical problems. Our results indicate that the proposed approach achieves a 5–15% reduction in the total retrieval time primarily by reducing picker blocking. We conclude that the IBM is particularly effective in narrow-aisle picking systems.     

Optimal quoting of delivery time by a third party logistics provider: The impact of shipment consolidation and temporal pricing schemes

Increased competition in business environments requires that firms provide not only quality but also timely service with minimal cost. Offering a delivery-time guarantee may increase the demand for a product or service, or allow the firm to charge a price premium. This paper investigates the effects of different pricing schemes for a Third Party Logistics (3PL) provider. The 3PL tenders a consolidated load to a carrier that line-hauls over a certain origin–destination lane. In a price- and time-sensitive logistics market, we derive the optimal quotations that should be made for price and delivery-time, with the objective of maximizing the profit rate of the 3PL provider. We propose four easy-to-use temporal pricing schemes, and derive the corresponding optimal length of shipment consolidation cycles and the prices. Depending on the logistics market parameters, we show that charging according to an order’s time of arrival is not necessarily the best pricing scheme. Various managerial insights and numerical examples with sensitivity analysis are provided.     

关系的分解

主要讨论关系的分解问题,我们从与序结构交叉的角度,建立了关系的分解理论。     

On RF-pairs, Bäcklund transformations and linearization of nonlinear equations

Some classes of nonlinear equations of mathematical physics are described that admit order reduction through the use of a hydrodynamic-type transformation, where the unknown function is taken as a new independent variable and an appropriate partial derivative is taken as the new dependent variable. RF-pairs and associated Bäcklund transformations are constructed for evolution equations of general form. The results obtained are used for order reduction of hydrodynamic equations (Navier-Stokes and boundary layer) and constructing exact solutions to these equations. A generalized Calogero equation and a number of other new linearizable nonlinear differential equations of the second, third and forth orders are considered. Some integro-differential equations are analyzed.     

Characterization through distributional properties of dual generalized order statistics

Distributional properties of two non-adjacent dual generalized order statistics have been used to characterize distributions. Further, one sided contraction and dilation for the dual generalized order statistics are discussed and then the results are deduced for generalized order statistics, order statistics, lower record statistics, upper record statistics and adjacent dual generalized order statistics.     

基于AC~2R模型的高校科研绩效评估及有效排序研究

分析高校科研绩效不仅要考虑其产出总量,更应考虑产出效率,本文基于AC2R模型对江苏18所高校的科研绩效进行评估分析,提出了一种前沿面投影绩效排序的方法对高校进行再排名,从而得出有效决策单元的排序,结果证明了方法的有效性。     

电流变液成链过程的一种序参量描述

A simple long-range-order parameterPis defined for describing the process of formation of chains in the electric field direction. The free energy of the system is taken to be the sum of the internal energy, the electrostatic interaction and configuration entropy as a function o P. Calculated results indicate that the critical parameter is a function of electric field, temperature, misfit dielectric coefficients and concentration of particles.     

一类广义AHP判断下的保序性问题

本讨论了一类基于两组元素比较的广义AHP判断下所用排序方法的保序性,并提出了一种特殊的广义判断阵,四四比较判断矩阵,供实际操作时参考。