加强领导落实责任认真做好青藏铁路建设用地管理工作

铁路建设用地验收交接的技术性、专业性、政策性较强,涉及面广。青藏铁路公司建设管理部采取“结合实际、突出重点、全面指导、整体推进”的做法,加强与地方政府土地管理部门的联系,参加建设用地的征用和施工用地的管理工作;主动与建设单位沟通,共商建设用地管理的对策;统一竣工资料的标准,保证竣工资料的齐全、规范;牢固树立为运输生产服务的理念,依法、规范、科学地管理铁路建设用地,保证建设用地交接完整、准确、规范地进行。     

船舶液力耦合器的人工神经网络的数学建模

从船舶动力装置动态建模与仿真的实际需求，引出了其主要部件之一的液力耦合器数学建模在稳／动态特性研究中的重要性，以及利用其试验曲线(输入特性形式)作为数据源去构建准稳态数学模型的困难之处：寻找一种通用的数学表达形式，以实现①液力耦合器在额定工况及其附近的试验曲线的内插与外廷；②过渡工况液力耦合器数学模型的设计(如液力耦合器接合和脱开过程其滑差从100％向额定滑差值方向的变化)。本文介绍了人工神经网络方法在液力耦合器动态建模中的应用。文章先介绍了其数学建模的思路和要点：①选择人工神经网络算法(包括传递函数)与结构(人工神经网络隐含层数目和神经元个数)；②提高人工神经网络泛化能力的措施；③利用专业知识扩充人工神经网络训练用的数据样本。然后叙述了其数学模型在某船舶动力装置稳态、动态特性计算机仿真研究中的某些有意义的结果：①正常航行(四机双桨)稳态工况时各车令下液力耦合器的滑差；②不同螺旋桨螺距下的液力耦合器接合过程的滑差变化；③怠速→前进五的急加速过程的滑差变化。     

Japanese perspective of driver information systems

A perspective view of of Japanese R&D activities of Driver Information Systems is given from the standpoint of developing joint projects by public and private sectors. First, a brief history of the R&D activities is illustrated from above mentioned standpoint. Then, two major projects, AMTICS and RACS, and the social backgrounds of these projects are explained. In order to give a clear idea of both projects some technical details are treated.Based on the history and the present status of the developments, the basic design conceptions of Japanese Driver Information Systems are explained and several factors or reasons which have influenced to the design conception are discussed. Then, the promoting systems of the R&D activities are generally explained and present status of the projects and future problems in developing more advanced systems are also handled. A brief discussion on the establishment of international standard is also mentioned as a final comment.     

Using longitudinal methods for analysis of a short-term transportation demonstration project

This paper documents an application of panel, or longitudinal data collection in the evaluation of a TSM (Transportation Systems Management) demonstration project. The project was a four-week demonstration of staggered work hours in downtown Honolulu during February–March 1988. The 4 wave panel survey elicited commuting experiences of approximately 2,000 downtown employees at two week intervals before and during the project. The sample involved both employees who participated in the project by shifting their work hours, and those who did not. The panel survey was augmented by floating-car observations of travel times on major routes into downtown Honolulu on the same four dates.The purpose of the analysis was to determine whether employee commute times were affected, and if so, how these changes were distributed among various employee segments. Two methods were used. First, travel time changes were estimated using paired t-tests. Second, regression equations were used to estimate project time savings as a function of trip length, route, and location of residence. Results show that travel time savings due to the project were typically small, less than ten percent. Nonparticipants experienced greater savings than participants, and some segments of participants experienced longer travel times during the project. The panel method proved to be an effective way to measure project travel time impacts and shows that the method is appropriate in short time applications.Presented at the Annual Meeting of Transportation Research Board, January 7–11. 1990, Washington, D.C.     

高应变法确定大直径混凝土管桩的承载力

在缺少大直径混凝土管桩静载试验的情况下,现在普遍采用了动测试桩的方法确定大管桩承载力。文中提出采用CASE法和CAPWAPC法相互比较来确定大管桩承载力的方法。     

提高牵引变电所故障测距装置精确度的对策

指出牵引变电所故障测距装置的精确度是动态变化的,应根据接触网、变电所设备及装置运行情况的变化及时调整故障测距整定值,以提高其精确度,提出电气化铁道复线并联供电时避免线路互感影响牵引变电所故障测距装置精确度的简便方法即复线单线化。     

引航员与船长间信息交流方式研究

引航员与船长之间在引航过程中的信息交流是至关重要的,它是达到安全引航的必要手段之一。以前,引航员上驾驶台后利用短暂的车、舵命令来了解船舶性能,与船长交流很少。事实上,他们之间各怀特长,引而不发,这给应急状态时的协同操作带来安全隐患。为使引航工作的安全更有保障,目前上海港引航管理站推出《船长/引航员信息交流卡》突出强调了信息交流在引航工作中的重要性。     

Aggregate expenditure elasticity for transport and communication in Australia

For the purpose of estimating Engel elasticity, one needs to find the best functional form among various alternatives. In this paper, a new function, which is called the double semi-log Engel function turns out to be the best functional form for the transport and communication items in Australia on the basis of the distance function (D²) criterion, and the non-nested hypothesis testing procedure. This function is then used to estimate total expenditure elasticity, and the percentage change in consumer demand due to changes in total expenditure and total expenditure inequalities; using the 1975–76 Household Expenditure Survey data. The results of the analyses demonstrate that transport and communication is a necessary item in Australia on the basis of two criteria, viz., its elasticity is not significantly greater than unity, and the percentage change in demand increases with a decrease of the total expenditure inequality [emphasised by Iyengar (I960)]. Policy implication of the analyses has also been discussed.     

强夯法在排水固结加固后地基工程中的应用

通过对地面变形、孔隙水压力的监测,分析了强夯施工时地基的有效变形率随夯击次数的变化规律及夯点的分布情况,以及强夯作用下土体中孔隙水压力的增长和消散规律,从而进一步找到了孔压增量与夯点距离的关系、孔隙水压力与深度的关系,及孔隙水压力的消散过程。并通过试夯验证和确定设计技术参数,施工后检验结果表明采用该法处理排水固结后地基对消除粗粒料过大的孔隙比、提高地基承载力、减少残余沉降和差异沉降都有极大的作用。