第二代完整稳性衡准的验证与改进研究

国际海事组织正在研究制定第二代完整稳性衡准,根据已经提出的参数横摇和纯稳性丧失的第一层薄弱性衡准建议方案,对我国5艘客滚船、5艘集装箱船、5艘油船和5艘散货船进行实船验证,对第一层薄弱性衡准的建议方案的适用性和合理性,提出必要的改进意见和建议,以完善新的国际完整稳性衡准规则。     

变速恒频发电中混合励磁发电机模拟双向电压调节器的设计

介绍一种应用于变速恒频发电系统中,“模拟双向调节”的混合励磁发电机的电压调节模式.该调压器为双向调节模式,满足了混合励磁发电机变速条件下可靠输出稳定电压的要求.设计了稳压器,验证了性能.     

制氢技术的机动应用研究与改进设计

阐述了电解水制氢技术在机动车上的应用研究与改进设计,详细介绍了系统组成、工作原理、主要性能参数、载车综合控制技术的研究设计和关键技术的解决、电解新技术的研究及新工艺的应用等.机动制氢技术已成功应用于我国"神舟"号系列航天飞行试验和"嫦娥一号"绕月工程的气象保障业务,及时检测"发射、回收窗口"的信息,为航天飞行试验提供可靠的气象参数.     

通信中间件技术在新一代CTC系统中的应用

新一代CTC系统综合了计算机技术、网络通信技术和现代控制技术,采用智能化分散自律设计原则.整个系统通常存在多种硬件系统平台,如工业控制机、工作站、小型机等,不同的操作系统及不同的网络协议和体系结构,如何把这些系统集成起来并开发新的应用是一个非常现实而困难的问题.为此,从安全性、可靠性、扩充性、易管理性、可用性和可移植性等综合因素考虑,提出了采取中间件的方式完成跨平台通信机制.     

Generating complete all-day activity plans with genetic algorithms

Activity-based demand generation contructs complete all-day activity plans for each member of a population, and derives transportation demand from the fact that consecutive activities at different locations need to be connected by travel. Besides many other advantages, activity-based demand generation also fits well into the paradigm of multi-agent simulation, where each traveler is kept as an individual throughout the whole modeling process. In this paper, we present a new approach to the problem, which uses genetic algorithms (GA). Our GA keeps, for each member of the population, several instances of possible all-day activity plans in memory. Those plans are modified by mutation and crossover, while bad instances are eventually discarded. Any GA needs a fitness function to evaluate the performance of each instance. For all-day activity plans, it makes sense to use a utility function to obtain such a fitness. In consequence, a significant part of the paper is spent discussing such a utility function. In addition, the paper shows the performance of the algorithm to a few selected problems, including very busy and rather non-busy days.     

Effect of land use on decisions of shopping tour generation: A case study of three traditional neighborhoods in WA

This study investigates the relationship between land use and shopping tour generation using an activity-based shopping model that captures the effects of land use patterns on household decisions of shopping tour frequency, tour scheduling and mode choice. The model was calibrated using travel data collected in three traditional neighborhoods located in the Puget Sound region, WA, and shopping travel patterns across seven common household structures were analyzed. The results reveal that land use patterns have virtually no impact on overall shopping tour frequency. However, land use does seem to be associated with decisions about the type of shopping tours undertaken. For example, households with poorer accessibility tend to make fewer one-stop shopping tours, and are more likely to combine shoppingtrips with other trips to form multi-stop shopping tours as a means of compensating for locational deficiencies. Finally, we also found that traditional neighborhood residents who live closer to the neighborhood commercial street, and thus, have greater accessibility, are more inclined to use non-auto modes for one-stop shopping tours.     

燃料电池控制系统自动代码生成

针对自行开发的软硬件平台,结合控制算法的Simulink模型设计了代码自动生成的方法,实现了基于Motorola PowerPC555单片机的电子控制单元和OSEK Turbo实时操作系统的燃料电池控制系统开发过程中的快速迭代,最终实现了快速控制原型开发。该控制系统经过10kW燃料电池发动机实验,取得了良好的控制效果。     

基于现场测试的道路压电俘能系统电学性能

为全面测评道路压电俘能系统在开放交通条件下的电学性能,采用16个自主研制的15 cm × 15 cm × 3 cm压电俘能装置并联,设计俘能模块布设点位,铺筑道路压电俘能系统现场测试段,基于随机开放交通条件下道路压电俘能系统开路电压波形信号响应特征,系统研究了现场不同荷载、不同车速工况下道路压电俘能系统电学输出规律,并...     

基于NURBS的船体曲面自适应三角网格剖分

针对面向曲面的三维船体性能计算和真实感图形显示问题,应用NURBS曲线、曲面理论,提出一种新颖的船体NURBS曲面三角形网格自动生成算法,运用四角编码方法和改进的曲面片平坦性检验方法,保证在递归分割船体NURBS曲面时,能够快速有效地分割出四边形网格,在曲面片的高度方向和边界处同时满足给定的精度要求,在此基础上,应用割角剖分算法将一个四边形网格剖分成两个或多个三角形网格。应用结果表明,应用该算法生成的三角形平面片能够较好地逼近船体曲面,避免出现网格间的裂缝,与二叉树、四叉树方法相比,四角编码方法明显节省了时间和空间,提高了算法效率。     

基于直流电网的异步发电系统控制策略

针对异步直流发电中变转速控制与变转矩控制相结合的新颖综合控制模式,介绍其发电系统的结构、变转速模式特性、转速寻优策略和转矩控制特性并给出具体方法。以柴油机组万有特性为着眼点,提出分级阶跃变转速策略和控制程序流程,通过Matlab/simulink搭建系统模型进行仿真试验以验证变速控制策略的正确性;以异步发电机和变换器为对象,提出基于直接转矩控制策略(DTC)的转矩控制模式,以实现单机直流电压的稳定;最终通过小比例试验验证转矩控制模式实现的可行性。