高速铁路列车间隔时间的计算方法

与普速铁路按固定闭塞方式组织列车追踪运行的控车模式不同,高速铁路由于装备了CTCS-2/3级列控系统和调度集中设备,故采取以车载信号作为行车凭证、按一次连续速度模式曲线监控高速列车运行的控车模式.基于高速铁路的这一控车特点,综合考虑列车的长度、运行速度、常用制动距离、安全防护距离、车站作业时间和闭塞分区长度等影响因素,借鉴普速铁路列车间隔时间的计算方法,给出高速铁路列车间隔时间(4种追踪间隔时间和7种车站间隔时间)的定义及其计算方法,为制定规范和统一的高速铁路列车间隔时间计算办法提供理论依据.     

基于元胞自动机的高速铁路列车群追踪运行仿真模型

为分析高速铁路列车在追踪间隔缩小时的运行状态,根据准移动闭塞系统原理,设置列车区间运行和车站运行的演化规则,建立准移动闭塞条件下基于元胞自动机的列车群追踪运行仿真模型。利用元胞自动机对京沪高速铁路线路"上海虹桥—南京南"运行图中追踪运行的10列车进行建模仿真,分析仿真结果验证到达间隔时间是制约追踪间隔的瓶颈,并得出后行列车满足追踪间隔4 min或3 min的情况下,其运行速度不受前行列车的干扰。     

Locating emergency vehicles with an approximate queuing model and a meta-heuristic solution approach

In this paper, the location of emergency service (ES) vehicles is studied on fully connected networks. Queuing theory is utilized to obtain the performance metrics of the system. An approximate queuing model the (AQM) is proposed. For the AQM, different service rate formulations are constructed. These formulations are tested with a simulation study for different approximation levels. A mathematical model is proposed to minimize the mean response time of ES systems based on AQM. In the model, multiple vehicles are allowed at a single location. The objective function of the model has no closed form expression. A genetic algorithm is constructed to solve the model. With the help of the genetic algorithm, the effect of assigning multiple vehicles on the mean response time is reported.     

预应力锚索抗滑桩结构在处治滑坡中的应用

文章结合鹰阳关-莲塘二级公路K54+800处滑坡采用预应力锚索结构施工实践,介绍了预应力锚索抗滑桩结构在滑坡处治中的注意事项及使用效果.     

带扰动观测器的船舶轨迹跟踪自适应动态面滑模控制

针对遭受未知外部环境扰动的三自由度全驱动船舶轨迹跟踪控制问题,设计一种带扰动观测器的自适应动态面滑模控制方法。该方法构造扰动观测器估计未知扰动,并对控制量进行前馈补偿,采用σ修正泄漏项的自适应律估计扰动观测误差的界以提高控制精度,结合动态面技术解决传统反演法的微分爆炸问题,并选取李雅普诺夫函数证明该控制器可保证闭环系统内所有信号的一致最终有界性。基于一艘供给船舶进行仿真试验,结果表明,所设计的控制器输出合理有效且跟踪精度高,在工程实际中具有一定的参考价值。     

Evaluation of pedestrian crosswalk level of service (LOS) in perspective of type of land-use

In India pedestrians usually cross the road at mid-block crosswalks due to ease of access to their destination or the development of adjacent land use types such as shopping, business areas, school and residential areas. The behaviour of pedestrian will change with respect to different land use type and this change in behaviour of pedestrian further reflects change in perceived level of service (LOS). So, it is important to evaluate the quality of service of such crossing facilities with respect to different land-use type under mixed traffic conditions. In this framework, pedestrian perceived LOS were collected with respect to different land-use type such as shopping, residential and business areas. The ordered probit (OP) model was developed by using NLOGIT software package, with number of vehicles encountered, road crossing difficulty as well as safety considered as primary factors along with pedestrian individual factors (gender and age), land-use type and roadway geometry. From the model results, it has been concluded that perceived safety, crossing difficulty, land-use condition, number of vehicles encountered, median width and number of lanes have significant effect on pedestrian perceived LOS at unprotected (un-signalized) mid-block crosswalks in mixed traffic scenario. The inferences of these results highlights the importance of land use planning in designing a new set of pedestrian access facilities for unprotected mid-block crosswalks under mixed traffic conditions. Also the study results would be useful for evaluating pedestrian accessibility taking into account different land-use type and planning required degree of segregation with vehicular movement at unprotected mid-block crosswalk locations.     

变步长BP网络优化导航雷达跟踪滤波系统的研究

本文提出了采用变步长ＢＰ网络实时处理导航雷达目标跟踪滤波数据。其原理是在ＢＰ算法中加入变动量因子,用Ｎ层变步长寻优进行前馈神经网络的学习。该算法能够根据输入时间序列的特点自适应调整网络优化步长,对匀速和变加速运动目标的稳定跟踪精度分别在７．５ ｍ 和１１ ｍ 以内,而对急转弯的目标抖动２～４ 次就能及时跟踪上     

Daily rhythms of suburban commuters’ movements in the Tallinn metropolitan area: Case study with mobile positioning data

The objective of this study is to analyse the diurnal rhythms of city life and its spatial differences in Tallinn, using mobile telephone positioning data. The positioning experiment was carried out in April 2006 over an 8-day period and 15-min intervals, with a random sample of 277 respondents living in new residential areas outside the city of Tallinn.The investigation of the space–time movements and daily distances of respondents showed that the majority of respondents had a similar temporal rhythm related to work, school, services and leisure in the city. Because of the different timing of those activities, the mobile positioning data made it possible to map functional differences in the city. The advantages and disadvantages of mobile positioning data in mapping urban life are discussed in the final section of the study.     

21世纪世界新秩序——几种基本理论模式述评

在人类进入21世纪之后，世界需要建立什么样的新秩序才能更好地服务于人类社会?这个问题激发了政治家和思想家们的极大兴趣，他们提出了各种各样的“理论”和“模式”。其中，较具代表性的有：“地球村”模式，世界政府模式，“和平区”与“动乱区”模式，“三大经济区”模式，“明冲突”模式，“单极霸权”或“单极主导下的多极合作”模式，两极或多极均势模式，等等。这些模式各以其独特的视角，试图勾勒出后冷战时代世界新秩序的“地图”。     

Orders of Automorphism Groups of the p~6 Groups of Family Φ_(24)

Using the metabelian property, regularity, p-commutativity and some properties of congruence, this paper gave the orders of automorphism groups of family Φ24, which are the groups of order p6 determined by Rodney James, where p denotes an odd prime.