Solving large multiple-depot multiple-vehicle-type bus scheduling problems in practice

We consider the multiple-depot multiple-vehicle-type scheduling problem (MDVSP) which arises in public transport bus companies and aims to assign buses to cover a given set of timetabled trips with consideration of practical requirements, such as multiple depots and vehicle types as well as depot capacities. An optimal schedule is characterized by minimal fleet size and minimal operational costs including costs for empty movements and waiting time. It is well-known that the MDVSP is NP-hard.Although progress has recently been made in solving large practical MDVSP to optimality with time-space network models, current optimization technology sets limits to the model size that can be solved. In order to approach very large practical instances we propose a two-phase method which produces close to optimal solutions. This modeling approach enables us to solve real-world problem instances with thousands of scheduled trips by direct application of standard optimization software. Furthermore, we introduce the concept of depot groups for the case that a bus may return in the evening into another depot than where it started in the morning.     

Fuzzy logic control of vehicle suspensions with dry friction nonlinearity

We design and investigate the performance of fuzzy logic-controlled (FLC) active suspensions on a nonlinear vehicle model with four degrees of freedom, without causing any degeneration in suspension working limits. Force actuators were mounted parallel to the suspensions. In this new approach, linear combinations of the vertical velocities of the suspension ends and accelerations of the points of connection of the suspension to the body have been used as input variables. The study clearly demonstrates the effectiveness of the fuzzy logic controller for active suspension systems. Suspension working space degeneration is the most important problem in various applications. Decreasing the amplitudes of vehicle body vibrations improves ride comfort. Body bounce and pitch motion of the vehicle are presented both in time domain when travelling over a ramp-step road profile and in frequency domain. The results are compared with those of uncontrolled systems. At the end of this study, the performance and the advantage of the suggested approach and the improvement in ride comfort are discussed.     

Image reconstruction of a buried perfectly conducting cylinder illuminated by transverse electric waves

This article presents a computational approach to the image reconstruction of a perfectly conducting cylinder illuminated by transverse electric waves. A perfectly conducting cylinder of unknown shape buried in one half‐space and scatters the incident wave from another half‐space where the scattered field is recorded. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations is derived, and the imaging problem is reformulated into an optimization problem. The steady state genetic algorithm is then employed to find out the global extreme solution of the cost function. Numerical results demonstrated that, even when the initial guess is far away from the exact one, good reconstruction can be obtained. In such a case, the gradient‐based methods often get trapped in a local extreme. In addition, the effect of different noise on the reconstruction is investigated. © 2006 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 261–265, 2005     

基于MEMS加速度传感器的双轴倾角计及其应用

利用MEMS加速度传感器设计了双轴倾角计,并采用单片机进行了线性化和温度补偿,倾斜角以模拟量和数字量2种形式输出。该倾角计体积小、重量轻、精度高,能够很好地满足MAV姿态控制及其他应用的倾角测量。     

常规控制和模糊PID控制在全垫升气垫船航向控制中的应用

本文详细的介绍了常规控制和模糊PID控制在全垫升气垫船的航向控制中的应用。气垫船是一种高性能船,其航向较常规船舶更难于控制。本文设计了常规PID控制和模糊PID控制器两种控制方法,并对气垫船的航向控制进行了仿真,从仿真结果可以看出,在气垫船受风力的作用下,模糊PID控制器在克服干扰方面具有比常规PID控制更好的效果。     

浅析电能供热方式发展方向

本文通过对电供热方式的分析和调研，认为电作为一种方便、洁净的能源，在供热领域有着很大的发展空间，伴随着峰谷电价政策的实施，必将进一步促进该领域科学技术突飞猛进的发展。特别是采用热泵和电热蓄能的供热方式以及冷热电联供方式，是电力资源用于供热的发展方向。     

模糊控制电火花加工系统的稳定性分析

本文针对电火花加工过程中具有明显的时变非线性的特点，在论述了模糊控制规律的实现方法基础上，应用模糊理论，推导了模糊逻辑关系及控制策略，设计了电火花加工系统的模糊逻辑控制器算法。并应用平衡态的概念和稳定性定理，从理论上阐述和分析了电火花加工伺服进给闭环模糊控制系统的稳定性。并通过实验验证了该方法的可行性及系统的稳定性。     

论加强建筑电气技术实践教学环节

建筑电气技术课程要求理论面广、实践性强，应根据课程特点结合行业规范化管理的要求、实际工程现场条件、现代化教学设备等各方面条件，适时调整教学计划，灵活多变地安排实践教学内容，加强实践教学环节，坚持“理论——实践——理论——实践”这一循环教学过程，提高实践教学的水平和质量。     

桥头软基路堤设计与施工必须注意的若干问题

桥头部基路堤施工关系到桥台与台背路堤间是否出现跳车现象的问题．从桥头软基路堤设计和施工的角度出发，提出桥台软基处治的施工研究，台背路堤料的选择，台背路堤填料的排水和施工方法，土工布摊铺方法，软基路堤沉陷观测和施工质量控制措施等软基路堤设计和施工必须注意的问题，对寻求解决桥头出现跳车现象具有指导作用．     

道路交通事故人-车-道路环境系统分析

本文通过对我国现阶段的道路交通事故的统计分析，提出了减少道路交通事故。必须从人-车-道路环境系统的各个环节进行人机分析，强调在整个系统中除解决人的驾驶适宜性和驾驶室的宜人性设计外，还着重强调了人-车-道路系统的协调性，并指出了目前尚未引起重视的道路设计．