Can agents measure up? A comparative study of an agent-based and on-line optimization approach for a drayage problem with uncertainty

Experiments studying the behavior of agent-based methods over varying levels of uncertainty in comparison to traditional optimization methods are generally absent from the literature. In this paper we apply two structurally distinct solution approaches, an on-line optimization and an agent-based approach, to a drayage problem with time windows under two types of uncertainty. Both solution approaches are able to respond to dynamic events. The on-line optimization approach utilizes a mixed integer program to obtain a feasible route at 30-s intervals. The second solution approach deploys agents that engage in auctions to satisfy their own objectives based on the information they perceive and maintain locally. Our results reveal that the agent-based system can outperform the on-line optimization when service time duration is highly uncertain. The on-line optimization approach, on the other hand, performs competitively with the agent-based system under conditions of job-arrival uncertainty. When both moderate service time and job-arrival uncertainties are combined, the agent system outperforms the on-line optimization; however, in the case of extremely high combined uncertainty, the on-line optimization outperforms the agent-based approach.     

散装水泥半挂车罐体改进的可行性

通过对散装水泥半挂车罐体原始结构的有限元分析，提出了原始的四仓结构在使用过程中存在的问题。为解决这一问题，将罐体由原始的四仓结构改为三仓结构。     

“伯克”级驱逐舰反导能力分析

美国海军的“伯克”级驱逐舰拥有强大的对地攻击能力,卓越的防空和对舰作战能力。本文剖析了“伯克”级驱逐舰的反导作战思想,对其探测跟踪能力,作战反应能力以及打击平台,区域防空,点防御和电子战等方面的能力进行详细的讨论,从而找出其反导作战存在的薄弱点,为反舰导弹突防研究提供参考。     

铁路货物运输速度和逾期率的调查与分析

市场经济对铁路货物运输的时效性有较高的要求,根据1999年对铁路货物运输状态调查抽样的数据,从管内和直通运输,运价里程,品类及运价号四个方面对铁路货物运输时效性服务水平进行分析评价,针对存在的问题提出了扩大开行快运列车,强化运输组织,加强作用管理,加快信息化进程等对策以提高铁路货物运输的时效性服务水平。     

泥水盾构主机推进速度与泥浆系统能力的匹配

通过分析泥浆系统流量与盾构掘进进度关系,对泥水盾构主机推进速度与泥浆系统能力的匹配进行了阐述,为盾构采购用户提供一些参考。     

Untangling process complexity in logistics delivery services with unpredictable service sequences: a mixed-method study of chemical tanker port calls

We explore the complexity issue relevant to a logistics service process characterized by unpredictable service stages and service sequences in the context of chemical tankers’ call in the Port of Houston. The operational dimensions of uncertainty and conflict surrounding process complexity are examined through a mixed-methods approach using both qualitative and quantitative data collected from the Port of Houston. We propose a taxonomy to classify several uncertainty and conflict factors emerged from our qualitative analysis, including structural conflict, structural uncertainty, infrastructural conflict, and infrastructural uncertainty. The case study findings are validated and triangulated by a quantitative analysis which quantifies the time and cost impacts of unproductive chemical tanker movement on port-call service performance. We contribute to the complexity theory by introducing four dimensions of process complexity to the stream of process-oriented logistics service research. These four complexity dimensions can be used by managers to untangle their process complexity. Our pseudo-service-stage based mapping technique will also be valuable for managers to visualize their service processes with unpredictable service sequences. Finally, we call for future research on synchronization across operational processes between service stages.     

地铁信号与屏蔽门联动控制系统分析

结合广州地铁详细地介绍了地铁信号与屏蔽门联动控制系统的组成、功能，分析了其原理和联动的安全性、可靠性，井指出了在实际运行中的重要性。     

论迟延交付的概念

通过法律逻辑的基本知识,分析我国《海商法》中未引进的“汉堡规则”中关于迟延交付的另一种情况——未在合理时间内交付,以减少理解上的分歧。     

DCY100型动力平板运输车

动力平板板运输车是造船厂钢结构船体分段在工序之间转运的主要设备，本文介绍了该车结构特点、主要技术参数、控制方式及应用范围。     

带有斜井的小断面隧道混凝土运输方案

系统介绍了中江人民渠引水隧道第2合同段二次衬砌混凝土运送方案，该方案主要利用小竖井投送混凝土解决了带有斜井的小断面隧道混凝土运送难题。同时阐述了混凝土运送方案的确定、实施过程以及方案实施的评价等。