Systematic budget allocation for transportation construction projects: a case in Taiwan

It has always been a daunting task for any government to allocate the budgets for public infrastructure effectively so as to maximize the benefits of the limited resources. The most important contribution this paper makes is to conduct an empirical study of the budget allocations of the six region-based road system construction plans in northern Taiwan using the transportation budget allocation model devised in this paper. After reviewing the results, the experts consulted while preparing this paper believe that these results are both objective and able to meet the actual requirements. The competent authority also believes that they are better than those obtained using their original approach. In particular, the construction of this model takes into consideration the highest-level supervisors. To a certain degree, it caters for the practices in budget allocation so that the managers are able to assume the authority corresponding to their responsibility concerning management efficiency and final outcomes.     

Experimental study on a model azimuthing podded propulsor in ice

The objective of this study was to investigate the performance of a model azimuthing podded propulsor in ice-covered water. Model tests were carried out with two different depths of cut into the ice (15 and 35 mm), two different ice conditions (presawn and pack ice conditions), and four different azimuthing angles. The depth of cut is the maximum penetration depth of the propeller blade into the ice block. The 0.3-m-diameter model propeller was operated in a continuous ice milling condition. Ice loads were measured by several sensors which were installed in various positions on the model. Six one-axis pancake-style load cells on the top of the model measured the global loads and two six-component dynamometers were installed on the shaft to measure the shaft loads. One six-component dynamometer was attached to the one of the propeller blades inside the hub to measure the blade loads. The pod unit and propeller performance in ice are presented. Ice-related loads, which were obtained when the blade was inside the ice block, are introduced and discussed. During the propeller–ice interaction, a blade can experience the path generated by the previous blade, which is called the shadowing effect. The effects of shadowing, depth of cut, azimuthing angle, and advance coefficient on propulsor performance are presented and discussed.     

Investigation of ship waves in a narrow channel

This paper presents a discussion of the characteristics of ship waves in a narrow channel restricted by vertical walls, based on observed data and the results computed by a 2-D model. In the numerical model, the propagation of waves generated by a moving ship is simulated by solving 2-D depth-integrated Boussinesq equations. To get the boundary conditions at the location of the ship, the slender-ship approximation is employed. A field observation was carried out at a straight length of navigation channel. The ships targeted in the observations are two kinds of waterbuses with lengths of 28 and 24 m. The relative depth Froude number for the river current, an appropriate parameter for assessing the influence of the current on ship wave characteristics in a navigation channel, ranged from 0.47 to 0.76. The observed maximum wave height varied between 0.13 and 1.26 m. The maximum wave height of the wave train is sharply increased when the relative depth Froude number exceeds 0.6. The results computed by the present model agree fairly well with the observed data.     

弹道导弹防御战略及技术发展的研究

弹道导弹的作战效能已经得到了充分的证明,对弹道导弹的防御逐渐受到了各国的高度重视.通过对比分析了美国和俄罗斯的弹道导弹防御系统的发展战略及基本思路,介绍了美围的弹道导弹防御系统的技术发展趋势,结合我国的实际情况,阐述了发展弹道导弹防御系统的思路.     

Trip generation of vulnerable populations in three Canadian cities: a spatial ordered probit approach

This paper provides an analysis of trip generation of three vulnerable groups: single-parent families, low income households, and the elderly. It compares the mobility of these groups to that of the general population in three Canadian urban areas of Hamilton, Montreal and Toronto, based on data from large-sample metropolitan transport surveys. An ordered probit model with spatially expanded coefficients is used for the analysis. Spatial expansion shows that there are spatial mobility trends for elderly populations and low-income populations even after socio-economic attributes are accounted for. Such spatial differences are not generally found for single parent families. This novel spatial analysis provides clues as to where vulnerable populations may experience greater degrees of social exclusion. It provides information to help prioritize transportation infrastructure projects or other social programs to take into account the needs of vulnerable populations with the lowest levels of mobility.     

基于SPH方法的波浪对水平板冲击的数值模拟(英文)

A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely used in the free-surface hydrodynamic flows with good accuracy. The improvement includes the employment of a corrective function for enhancement of angular momentum conservation in a particle-based calculation and a new estimation method to predict the pressure on the horizontal deck. The simulation results show a good agreement with the experiment. The present numerical model can be used to study wave impact load on the horizontal deck.     

京津城际铁路电务系统维护工作的调研及建议

京津城际铁路的开通运营,对信号设备维护管理提出了全新的要求.只有不断探索、创新设备维护管理方式和方法,才能确保350 km/h高速列车的运行安全.     

无人机战术控制系统研究

介绍美国针对无人机技术提出的战术控制系统(Tactical Control System,TCS).从TCS的组成、系统结构和功能、当前的发展、取得的成果以及现有的缺点和今后进一步发展等方面进行了简单分析,为进一步研究舰载无人机舰面战术控制系统提供参考.     

如何自行安装C&C08交换机的Centrex系统

集中式用户交换机(Centrex),也叫虚拟小交换机,是局用程控交换机的一种软件业务,不仅具有用户交换机(PBX)的基本功能,如群内短号拨打、话务转接、用户权限修改和立即计费等,而且用户还可享受普通电话用户的各种权利和业务,其最大好处是节省了PBX设备及维护.     

路面基层厚度探地雷达检测效果分析

对用探地雷达进行公路路面基层厚度的检测，分别研究了不同因素对检测效果的影响，对不同铺筑阶段的基层厚度，采用不同的天线频率，对比了检测结果，并分析横向电磁波速度不均匀对厚度检测效果的影响，以及接触式天线的垂向颠簸对基层厚度检测精度的影响，为道路工程检测提供参考。