大型舰船电力系统新型综合保护的研究

根据大型舰船电力系统的独特特性,确定电流差动保护作为本系统的首要保护策略的基础上,提出了以舰船电力系统快速区域保护为基础,基于矩阵算法的故障后电力网络快速重构的新方法。在快速故障诊断与故障隔离后,快速故障重构算法将迅速对电力网络剩余部分进行功率平衡,减少故障对电力系统的冲击。     

统计分析中的矩阵方法

引入矩阵的对角均差概念，将计算双因素积指标的因素影响值转化为计算矩阵的对角均差。通过适当的变换，商指标、积和指标以及加权平均指标的因素影响值也都能用矩阵方法求解，从而使统计指标的因素分析方法在一定程度上得到了统一与简化。     

Evaluation,prioritization and selection of transportation investment projects in New York City

Over the last decade, a large number of high capital cost transportation projects have been proposed for the New York City Region. Many have resulted from addressing evolving capacity needs, changes in regional demographics and economics, meeting the improvements necessitated by operating century old subway systems and recognizing the impact of moving freight in a dense region. But the catalyst for bringing all of these projects to the attention of the public and all regional agencies was the tragedy of September 11, 2001. While these projects entail massive investments ($50–$60 billion), little analytical work has been carried out to measure the transportation and economic costs and benefits they entail and to categorize them accordingly. Competition among agencies to secure adequate resources to implement any of the desired projects makes such analysis necessary; yet there still remain political, vested economic interests and agency rivalry barriers to achieving this important planning objective. This paper reports the methodological approach taken by these authors for consistent and transparent project evaluation and then presents results from the ranking and prioritizing methodology. The policy underpinnings and implications of the analysis are discussed in a subsequent paper and thus only briefly touched upon here in the concluding section.     

科研软件与商用软件在长江干流航道GPS测量控制网数据处理中的结果分析

利用GPS静态观测组成的同步环,当采用高精度的科研软件与常用商用软件解算基线时,由于解算基线向量的数学模型不同,致使其方差阵不同,前者解算的方差阵结构完全、严密。在进行GPS网平差时,两种软件在同种情况下的平差结果也有所差别。本文利用长江中下游航道一特大型GPSC级测量控制网的观测数据,着重将两种软件解算的基线和网平差结果进行了比较分析,得出了一些有益的建议和结论。     

基于贝叶斯智能学习OD矩阵估计与网络拓扑优化研究

OD矩阵（Origin—Destination Matrix）是路网规划与评价的基础数据。以往OD矩阵数据是通过交通调查的方法获得，这往往耗费了大量的人力和物力。运用贝叶斯定理的先验分布原理，构造贝叶斯智能学习的网络拓扑结构，提出由各路段交通流量的观测值来推算估计以及预测OD矩阵的一种有效方法。利用此方法可以准确估计出OD矩阵数据，同时在优化网络拓扑中，能对未来交通量的分配进行预测。对比分析表明，此方法能有效地提高交通运输规划的效率以及交通评价准确性。     

摩托车整车降噪的前提与基础 ——噪声源识别

噪声源识别是整车降噪的前提与基础,对于噪声试验不合格的摩托车,采用以声阵列技术为核心的噪声源识别方法,可快速准确地找到主要噪声源,明确噪声超标的根本原因,为降噪工作的开展指出明确的技术方向。     

交通事故摄影图像的自标定三维重建及其实现方法

为避免测量过程中在现场设置标定参考点,研究了以基础矩阵估计为基础的交通事故摄影图像自标定模型,并分析了其实现过程。把便于递推实现的无限对称指数滤波器引入平均梯度矩阵计算,实现了图像特征点的检测;通过匹配强度系数计算,对两幅图像的特征点进行了匹配;分析了基础矩阵计算及不良匹配点剔除的最小中值二乘法;对通过本质矩阵分解标定摄影图像的实现过程进行了论述。通过实验对模型及其实现方法进行了验证。     

气动力矩阵和气动导数对桥梁颤振稳定性的影响

采用集中气动力矩阵和一致气动力矩阵2种不同形式的气动力矩阵,并利用4种不同截面的气动导数研究了气动力矩阵对颤振临界状态的影响;采用理想平板的气动导数研究了各气动导数对颤振临界状态的影响。结果表明:采用集中气动力矩阵可降低颤振临界风速,使结果偏于保守;各气动导数对量纲一的风速和颤振临界风速均有一定影响,而对颤振频率影响较小,从而进一步证实了采用流线型断面形式的桥梁,其颤振形态是弯扭耦合的经典颤振。     

Robust state feedback stabilization of articulated steer vehicles

In this work, a full-state feedback controller is designed to prevent the oscillatory instability or snaking behaviour of an articulated steer vehicle. To design the controller, first, a linearized model of the vehicle is developed and analyzed to identify the most important uncertain tire parameters with regard to the snaking mode. By using this linearized model, the equations of motion are represented in the form of a polytopic system, which depends affinely on the most important uncertain tire parameters. Then, by solving some linear matrix inequalities, both the Lyapunov and state feedback matrices for the robust stabilization of the vehicle are found. The performance of the resulting controller is evaluated by conducting several simulations based on the linearized model. To verify the results from the linearized model analysis, some simulations are also done by a virtual prototype of the vehicle in ADAMS. The results based on the linearized model are reasonably consistent with those from the simulations in ADAMS. They show that the controller can effectively stabilize the vehicle during the snaking mode in different driving conditions.     

车用球轴承涡轮增压器临界转速分析

阐述了增压器轴承—转子系统临界转速的计算分析方法,以某车用球轴承涡轮增压器为例,分别采用Riccati传递矩阵法和DyRoBeS有限元法计算了临界转速,并进行了试验验证。由两种计算方法所得到的1阶和2阶临界转速值与试验值比较,1阶相差5.59%与1.42%,2阶相差2.53%与8.40%。同时,计算分析了轴承刚度、轴承结构尺寸、涡轮材质等参数对增压器临界转速的影响,得到了相关曲线。