基于DSP控制的SRD系统在船舶辅助动力系统中的应用研究

为提高内河航运船舶的机动性能和适航能力,以四相8/6极37kW开关磁阻电动机为研究对象,基于TMS320F2812DSP控制芯片,采用双闭环控制方式,以H桥型主电路作为功率变换器电路,设计了一套可用于船舶辅助动力装置的开关磁阻电机调速系统.实践表明,该系统具有工作可靠、控制灵活、运行效率高、容错能力强等特点,显著提高了...     

基于H．264／AVC标准的CABAC算法研究

文章首先对H．264／AVC标准进行了简要介绍,然后分析了H．264标准中所涉及到的关键技术：帧间预测、帧内预测、DCT变换以及熵编码技术等,重点对基于上下文自适应的二进制算术熵编码（CABAC）进行了研究。在CABAC上下文模型的建立,预编码,分析其概率模型估计及更新办法中对基于表格的二进制算术编码（利用查表方式）进行了重点研究,有效的降低算法复杂度。     

基于改进型遗传算法的舰艇航路规划研究

针对当前舰艇航路规划所要考虑的因素,运用遗传算法探讨舰艇的航路的优化设计问题。运用蚁群搜索的策略生成初始航线种群,并采用网格序号进行一维编码,通过构建适应度函数进行航线的选优工作。以电子海图作为平台,经过编程仿真试验得到了设定海区的最优航线。仿真结果表明,改进的遗传算法提高了搜索效率,得到了较为满意的结果,基本可以解决设定海区的航路规划问题。     

水面舰艇避雷针防护区域评估方法

在广泛研究国内外避雷针防护评估方法的基础上,提出适用于我国水面舰艇现状,并与当前单根避雷针评估一致性较好的雷电防护区域评估方法,为补充完善我国水面舰艇避雷针防护的评估方法体系奠定基础.     

船舶动力装置可组态智能故障诊断系统设计

旋转机械是许多船舶动力装置的核心设备,其设备状态与安全性直接关系到船舶航行的安全.为了保障船舶安全正常航行,针对当前船舶动力装置故障诊断系统的不足,研究开发了基于旋转机械监测诊断技术、数据库技术、网络技术以及组态式软件技术的船舶动力装置可组态智能故障诊断系统,介绍了该系统的体系结构、硬件结构、软件功能、网络技术及特点....     

基于排队论的大型舰船甲板弹射器数量研究

为明确大型舰船飞行甲板弹射器数量设计的理论依据,从调运指挥官的角度提出了"虚拟队列"概念,分析了其工作特点,对其工作模式进行了排队论建模.同时分析、建立了舰载机在弹射等待过程中的真实排队模型.忽略其它甲板因素的影响,基于排队论假设代入数值计算了不同弹射器数量对虚拟队列中舰载机的等待队长、系统等待耗时等关键指标的影响,使...     

Trial-and-error method for congestion pricing scheme under side-constrained probit-based stochastic user equilibrium conditions

A toll pattern that can restrict link flows on the tolled links to some predetermined thresholds is named as effective toll solution, which can be theoretically obtained by solving a side-constraint traffic assignment problem. Considering the practical implementation, this paper investigates availability of an engineering-oriented trial-and-error method for the effective toll pattern of cordon-based congestion pricing scheme, under side-constrained probit-based stochastic user equilibrium (SUE) conditions. The trial-and-error method merely requires the observed traffic counts on each entry of the cordon. A minimization model for the side-constrained probit-based SUE problem with elastic demand is first proposed and it is shown that the effective toll solution equals to the product of value of time and optimal Lagrangian multipliers with respect to the side constraints. Then, employing the Lagrangian dual formulation of the minimization method, this paper has built a convergent trial-and-error method. The trial-and-error method is finally tested by a numerical example developed from the cordon-based congestion pricing scheme in Singapore.     

An improved cellular automata model for heterogeneous work zone traffic

This paper aims to develop an improved cellular automata (ICA) model for simulating heterogeneous traffic in work zone. The proposed ICA model includes the forwarding rules to update longitudinal speeds and positions of work zone vehicles. The randomization probability parameter used by the ICA is formulated as a function of the activity length, the transition length and the volumes of different types of vehicles traveling across work zone. Compared to the existing cellular automata models, the ICA model possesses a novel and realistic lateral speed and position updating rule so that the simulation of vehicle’s lateral movement in work zone is close to the reality. The ICA model is calibrated and validated microscopically and macroscopically by using the real work zone data. Comparisons of field data and ICA for trajectories, speed and speed–flow relationship in work zone show very close agreement. Finally, the proposed ICA model is applied to estimate traffic delay occurred in work zone.     

汶川震后杨家山隧道断层塌方成因及其地质雷达预研究

受汶川地震的影响,经过断层带的公路隧道在施工时更容易出现大的塌方事故.为避免造成人员伤亡和经济损失,本文以广甘高速公路杨家山隧道右洞桩号K22+624段塌方为工程背景,采用现场地质描述分析、地质雷达探测,以及编写程序的正演模拟相结合,对汶川地震过后断层带对隧道塌方的影响进行研究.结果表明,在震后断层带的影响范围内,围岩整体特性发生突变,雷达波形图中会形成强烈的反射波信号,经过后期处理,能够得到较为清晰的波形异常图,从而推测出掌子面前方可能出现塌方的情况.文章最后对地质雷达探测加以正演模拟,可有效地指导整个隧道施工过程,并取得较好的经济收益.     

基于交通污染评价的道路立体交叉分解方法

根据交通污染评价的需要,对道路立体交叉的分解方法进行了研究.选取典型的左出左入式、左出右入式、右出左入式、右出右入式、环圈式左转匝道和斜线式、单(复)曲线式、反向曲线式、平行线式右转匝道,对常见的三路立体交叉和四路立体交叉分解方法进行了研究.以黑龙江省鹤大立交为例进行了实际分析.结果表明,该方法能够将常见的立交形式分解成为一个个的组成单元,进行交通污染评价时,可以先研究这些组成单元的污染情况,再将多个单元进行组合研究道路立交整体的污染情况.