矩阵方程AX=B的自反解与反自反解及最佳逼近

给定两个广义反射矩阵P,Q,通常对于矩阵方程AX=B关于P,Q的自反解和反自反解的研究大多是通过矩阵分解或广义奇异值分解来进行的。采用广义逆,建立该方程存在自反解和反自反解的充要条件以及解的一般表达式,并研究与之相关的矩阵最佳逼近问题。     

交互式识别在SAR图像目标识别中的应用

由于SAR成像机理、强斑点噪声等特点及受分辨率影响，导致SAR图像不直观，特别是对复杂形体小目标的解译相当困难．基于此，文中提供了基于“3S”技术的交互式识别，该方法利用构像方程原理，在“3S”技术（GPS，RS，GIS）和图像数据库的支持下，借助直观的光学图像来识别SAR图上的小目标，以及一些难以判读的大型目标，取得了比较好的识别效果．     

改善矮主墩连续刚构结构受力的措施及可行性探讨

提出并分析改善矮主墩连续刚构结构受力的措施,以计算实例对比分析了各种措施的实施效果,探讨不同措施的实施可行性。     

杭州湾大桥北航道桥结构优化研究

应用三维空间有限元模型,进行斜拉桥结构优化设计。利用有限元法进行结构分析,求出优化所需的状态变量,挠度、应力和频率。综合考虑设计变量、状态变量和目标函数的联系,应用混合罚函数建立优化模型。运用一阶优化计算方法和引入灵敏度分析进行算法优化,使结构在应力、变形和频率等约束条件下达到最小造价。以通用有限元软件ANSYS作为平台,编制相应程序,综合考虑斜拉桥结构静力性能和动力性能,用两种不同方案对杭州湾大桥北航道桥主桥进行结构优化设计,使全桥造价分别降低9 1%和5 5%。     

Structural safety assessment of a pontoon-type VLFS considering damage to the breakwater

 A structural safety assessment of a pontoon-type very large floating structure (VLFS) surrounded by a gravity-type breakwater was carried out for extreme wave conditions by considering the damage to the breakwater. Bending and shear collapses are considered to be a failure mode of the floating structure, while overturning damages the breakwater. The probability of the breakwater overturning, and the transmitted wave height before and after damage to the breakwater, are evaluated using design formulae for port and harbor facilities in Japan. The ultimate bending and shear strengths of the floating structure are calculated by the idealized structural unit method (ISUM) and FEM, respectively. The calculated failure probability for the floating structure is compared with the specified target safety level. It was found that the floating structure under consideration is most likely to fail by bending in transverse waves, and that the corresponding failure probability satisfies the target level. Received: September 12, 2002 / Accepted: October 4, 2002 Acknowledgment. The authors are grateful to Dr. Shigeo Ohmatsu, National Maritime Research Institute, Japan, for allowing us to use the program of hydroelastic response analysis. Address correspondence to: M. Fujikubo (e-mail: fujikubo@naoe.hiroshima-u.ac.jp) Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Arthit Jpn 2002;190:337–345)     

A stated preference examination of time of travel choice for a recreational trip

A stated preference experiment was performed in Calgary in Canada to examine how people are influenced in the selection of a departure time for a hypothetical trip to see a movie. A total of 635 complete observations were obtained. In each observation the respondent was presented with a set of possible departure time scenarios and asked to indicate the order of preference for these scenarios. Each scenario was described by specifying the automobile travel time, the expected arrival time relative to the movie start time, the parking cost, the probability of being at least ten minutes late for the movie and the length of time the movie had been running. This forced the respondent to trade off between conditions regarding these attributes. Age, gender and frequency of movie attendance were also recorded. The observations thus obtained were used to estimate the parameter values for a range of alternative utility functions in logit models representing this choice behaviour. The results indicate that all of the attributes included have significant effects on departure time choice in the situation being considered. They also indicate that travellers are prepared to arrive roughly two minutes early for each minute of travel time saved; that the money value of driving time for trips to recreational activities is about half that for trips to work; that one additional percent in the probability of arriving late is equivalent to roughly 0.20 Canadian dollars or 1.93 minutes drive time; and that there is a preference for a non-zero expected early arrival time regardless of the associated probability of arriving late. Some of these results are novel and others are consistent with findings for work trips in work done by others, which is seen to add credence to the approach being used here.     

海上蒸发波导下的电波传播衰减测量方案设计

介绍电磁波单程传播衰减理论，以及传播衰减和雷达作用距离之间的关系，在分析雷达作用距离对大气波导高度的敏感性基础上，设计雷达电磁波传播衰减特性的测量方案。     

高速铁路综合调度系统体系结构的研究

利用计算机最新发展技术,结合高速铁路运输特点,从系统的角度提出基于三层C S体系结构的高速铁路综合调度系统结构模型和体系结构,采用消息中间件技术,构成高速铁路综合调度系统的关键业务平台,实现系统各主要业务的集成,充分利用既有信息系统的成功经验及软件复用技术,构成一个完整、统一、标准的高速铁路综合调度系统。依据本研究结果所设计的高速铁路综合调度系统仿真试验系统已经建成。     

帆板航速预测计算模型探讨

在帆板运动平衡方程的基础上建立帆板的航速预测,依据最小阻力、最大推力原理求得各条航线上的最大船速,介绍帆板航速预测的计算方法,为帆板航速预测与航线选择的进一步研究做准备。