基于 MOPSO 算法的小型化复合结构槽螺旋天线设计

文中设计了一个复合结构的平面螺旋天线,并加载了贴片电阻和外圈铜环,使用多目标粒子群优化算法,利用Matlab软件实现了分布式协同优化仿真,达到了小型化的设计目的．仿真结果表明：在1.1～18 GHz频段内回波损耗小于－10 dB,在0.8～18 GHz频段内轴比小于3 dB．与传统的平面螺旋天线相比,该天线的直径仅为54 mm,且天线的电性能得到了提高．     

Urban transportation and the press: A survey of editorial opinion

The editorial opinions expressed in the news press can provide information on which issues are currently prominent concerns of the public, and on how public opinion may be aligned on those issues. A survey of all urban transportation-related editorials appearing in a sample of 155 U.S. newspapers during a period of 19 months in 1973–74 revealed that a number of issues related to transit financing, transit and highway investment, bicycles, and the transportation planning process were currently under debate in the urban press. This paper presents the survey's findings regarding the incidence and viewpoint of articles on these and other issues. Transit financing concerns clearly emerged as the most frequently discussed, and some agreement in editorial viewpoint was also found. The paper concludes with the authors' subjective observations on the scope and style of editorial discussion of urban transportation issues.This paper was prepared as background work for a recently-published essay on urban transportation problems (Kemp and Cheslow, 1976). The opinions expressed are those of the authors, and do not necessarily reflect the views of The Urban Institute or its sponsors.     

城市轨道交通降级运营中安全控制的缺失与对策——对上海轨道交通10号线“9·27”追尾事故的反思

对城市轨道交通线路发生设备故障降级运营时的安全控制方法做了全面的介绍。结合上海轨道交通10号线"9.27"追尾事故的发生,分析了城市轨道交通降级运营中安全控制的缺失和原因,并提出相应的改进对策。无论采用什么方法维持行车设备故障时的降级运营,确保行车安全都是运营管理人员必须要考虑的第一要素。很多时候越是简单的方法越能在实际工作中取得良好的效果,同时要加强多种贴近实际的应急演练。     

Multiclass fuzzy user equilibrium with endogenous membership functions and risk‐taking behaviors

Over the last decades, several approaches have been proposed in the literature to incorporate users' perceptions of travel costs, their bounded rationality, and risk‐taking behaviors into network equilibrium modeling for traffic assignment problem. While theoretically advanced, these models often suffer from high complexity and computational cost and often involve parameters that are difficult to estimate. This study proposes an alternative approach where users' imprecise perceptions of travel times are endogenously constructed as fuzzy sets based on the probability distributions of random link travel times. Two decision rules are proposed accordingly to account for users' heterogeneous risk‐taking behaviors, that is, optimistic and pessimistic rules. The proposed approach, namely, the multiclass fuzzy user equilibrium, can be formulated as a link‐based variational inequality model. The model can be solved efficiently, and parameters involved can be either easily estimated or treated as factors for calibration against observed traffic flow data. Numerical examples show that the proposed model can be solved efficiently even for a large‐scale network of Mashhad, Iran, with 2538 links and 7157 origin–destination pairs. The example also illustrates the calibration capability of the proposed model, highlighting that the model is able to produce much more accurate flow estimates compared with the Wardropian user equilibrium model. Copyright © 2016 John Wiley & Sons, Ltd.