Construction and algebraic characterizations of a planar four-index transportation problem equivalent to a circularization network flow problem

In this study, a circularization network flow problem with m?+?n?+?2 nodes and (m?+?1)(n?+?1) arcs is described as a planar four-index transportation problem of order 1?×?m?×?n?×?1. Construction and several algebraic characterizations of the planar four-index transportation problem of order 1?×?m?×?n?×?1 are investigated using the generalized inverse and singular value decomposition of its coefficient matrix. The results are compared with some results we obtained on the transportation problem with m sources and n destinations. It is shown that these problems can be solved in terms of eigenvectors of the matrices J _m and J _n , where J _m is a m?×?m matrix whose entries are 1.     

城市群快速轨道客运系统建设策略分析

城市群空间的形成要求借助于区域或城市间的完善的交通网络体系,许多城市群建立以大容量的快速轨道客运系统为骨干,地面辅以常规多类型公共交通网络为补充的多层次、多元化、立体化的客运交通方式相互协调的综合客运交通体系,并以此城市群综合客运交通体系为城市交通发展的基本战略。本文在此主要研究我国城市群快速轨道交通规划中的建设策略。     

江西经济发展走势对运输需求的分析与预测

区域经济的发展是运输需求的源泉。新世纪以来,江西经济进入了持续稳定发展的快车道,极大地促进了运输需求的持续增长,运输线路长度不断延长,全社会运输量不断增加。随着江西经济社会快速发展,城镇化进程的加快,资源环境约束压力的加大,运输需求结构提升,对运输需求提出了更高的要求,运输需求多样化、个性化、机动化、快速化和网络化的趋势更加显著。     

Influence of back angle on the quality of sleep in seats

Nocturnal sleep was assessed electroencephalographically in 9 males aged between 29 and 48 (mean 36·5) years in bed and in three seats with back angles to the vertical of 49·5° (sleeperette), 37·0° (reclining seat) and 17·5° (armchair).

Sleep in the sleeperette did not differ from that in bed, but in the reclining seat the duration of sleep was reduced and the amount of awake activity was increased. Sleep in the armchair was markedly worse than in any of the other three conditions. Total sleep time was shorter and awake activity was increased with more awakenings. Sleep efficiency was also reduced.

It would appear that adequate sleep may be obtained in seats as long as the back angle with the vertical approaches 40°.     

习家口油田集输系统清洁生产工艺改造

习家口油田单井管线腐蚀严重,经常发生管线穿口事故。由于伴生气量少,翻斗计量工艺无法运行。针对这种情况采用流量计计井口计量和树杖状串联常温集输工艺,降低了能耗,避免了运输油过程中的烃类气体的排放,减少了环境污染。据统计,习家口油田年减少烃类气体挥发100万方左右,生产运行费用大幅降低,取得了较好的经济效益。     

Stores clustering using a data mining approach for distributing automotive spare-parts to reduce transportation costs

Clustering of retail stores in a distribution network with specific geographical limits plays an important and effective role in distribution and transportation costs reduction. In this paper, the relevant data and information for an established automotive spare-parts distribution and after-sales services company (ISACO) for a 3-year period have been analyzed. With respect to the diversity and lot size of the available information such as stores location, order, goods, transportation vehicles and road and traffic information, three effecting factors with specific weights have been defined for the similarity function: 1. Euclidean distance, 2. Lot size 3. Order concurrency. Based on these three factors, the similarity function has been examined through 5 steps using the Association Rules principles, where the clustering of the stores is performed using k-means algorithm and similar stores are allocated to the clusters. These steps include: 1. Similarity function based on the Euclidean distances, 2. Similarity function based on the order concurrency, 3. Similarity function based on the combination of the order concurrency and lot size, 4. Similarity function based on the combination of these three factors and 5. Improved similarity function. The above mentioned clustering operation for each 5 cases addressed in data mining have been carried out using R software and the improved combinational function has been chosen as the optimal clustering function. Then, trend of each retail store have been analyzed using the improved combinational function and along with determining the priority of the depot center establishment for every cluster, the appropriate distribution policies have been formulated for every cluster. The obtained results of this study indicate a significant cost reduction (32%) in automotive spare-parts distribution and transportation costs.     

A fuzzy assessment framework to select among transportation investment projects in Turkey

Selecting the best transportation investment project (TIP) is often a difficult task, since many social, environmental and economic criteria have to be considered simultaneously. Evaluating a set of different projects, especially the best set of alternatives, portfolios, is even more complex. Pursuing the goal of selecting the best TIP portfolio, we propose a fuzzy assessment method to aid the selection process of a multi-criterion project by utilizing the concept of entropy and interval normalization procedure in a fuzzy analytic hierarchy process (F-AHP). Then, regarding this informative phase, we propose a fuzzy linear programming model to select the best TIP portfolio under uncertain cost pressure. A real case study is conducted to illustrate the efficiency of the proposed method.     

基于GSM GPS短消息的车载移动终端的设计与实现

为了解决对城市车辆进行实时监督和统一管理的问题,基于GPS全球定位系统和GSM数字蜂窝网,以性价比较高的AVR微控制器开发设计了GPS车载移动终端设备.终端通过GPS获取当前位置和时间信息,并以短消息的形式通过GSM网络发往监控中心,在中心的电子地图上实时地显示出来.同时监控中心的控制指令,如跟踪监听,遥控设置等,通过GSM网络发往车辆上的终端设备,从而实现了系统的交互运作.终端功耗低,体积小,操作简单,便于在系统升级和维护.     

出租车管理系统与交通公共信息平台数据交换方式研究

本文以上海大众交通（集团）有限公司提供的出租车GPS数据为基础,通过对源数据进行过滤和处理,满足了交通公共信息平台数据应用要求,实现了交通管理和建设所需要数据的提取,提高了交通资源的利用率.     

煤柱(Coal Log)在水力输送管道内的流动性状

煤柱水力输送管道（CoalLogPipeline）是目前正在美国进行研究和开发的一种最新型的管道输煤技术．本文就这种管道输煤技术的水力学原理，即压制成圆柱形的煤柱在管道中的流动性状进行分析讨论．这些流动性状包括管道煤柱流的区域划分，煤柱的起动速度和悬浮机理，以及沿管道的压力损失．通过分析导出的有关的水力学计算公式简单易行，可为煤柱水力输送管道的设计提供基本的设计参数．