基于通信的列车控制系统移动数据通信关键问题的探讨

首先分析了基于通信的列车控制(Communication Based Train Control,CBTC)系统移动数据通信的现状、特点、要求;然后分析了无线数据平台使用的技术:直接序列扩频、全双工、时分复用多址、码分复用多址、差错控制、移动性管理、数据通信协议;最后分析了CBTC信息内容和数据安全传输方法。     

Post-disaster evacuation and temporary resettlement considering panic and panic spread

After a disaster, a huge number of homeless victims should be evacuated to temporary resettlement sites. However, because the number of temporary shelters is insufficient, as are shelter building capabilities, victims must be evacuated and resettled in batches. The perceived psychological penalty to victims may increase due to heightened panic when waiting for evacuation and resettlement, whereas psychological interventions can decrease the magnitude of this panic. Based on the susceptible–infective-removal model, panic spread among homeless victims and other disaster-affected people is modeled, while considering the effects of psychological interventions on panic spread. A function is derived to compute the increase in the number of victims to be evacuated due to panic spread. A novel mixed-integer linear program is constructed for multi-step evacuation and temporary resettlement under minimization of panic-induced psychological penalty cost, psychological intervention cost, and costs associated with transportation and building shelters. The model is solved by aggregating objectives into a single objective by assigning weights to these objectives. With Wenchuan County as the test case, the epicenter of the 2008 Sichuan earthquake, the influence and the sensitivity of parameters, tradeoff among costs, and the effects of various functions of panic strength on psychological penalty and monetary costs are assessed using six experimental scenarios. Analytical results reveal the complexity and managerial insights gained by applying the proposed method to post-disaster evacuation and temporary resettlement.     

Pro／E软件在钣金结构件放样图中的应用

以实际使用的海德箱体不锈钢304钣金结构件生产制造过程中利用Pro/E软件进行钣金放样的实例,说明了Pro/E软件钣金放样实践过程,克服传统钣金结构件设计质量不稳定、浪费材料的缺陷,达到了准确、快速、方便、高效钣金放样的目的。     

瞬态瑞雷面波法检测路面强度的应用研究

针对目前水泥混凝土路面强度检测的缺陷,提出了利用瞬态瑞雷面波法无损检测路面强度的基本原 理和方法。通过工程试验实例验证:瞬态瑞雷面波法能较好地实现对水泥混凝土路面强度的无损检测,且检测方法 简单、可靠,具有较高的工程实用价值。     

管道焊接展开曲线的计算机辅助设计

针对管道铺设及桥梁施工过程中大直径管道间的焊接问题,应用CAD手段进行分析计算,给出了管道相贯处工程展开曲线,为工程施工提供理论依据.     

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分析了主城对卫星城市经济扩散作用与热传导现象的相似性，引入了经济扩散通量的概念．参照热传导的傅立叶定律，建立了主城对卫星城市基于交通通道的经济扩散模型．模型表明主城对卫星城市的经济扩散通量与其间交通通道的通过能力及两城市间的产业梯度呈正比．提出卫星城市规划应以经济扩散通量为依据，首先选择经济扩散通量大的城镇为卫星城市，对经济扩散通量小而与主城产业梯度高的周边城镇，可以通过交通通道建设来培育其向卫星城市发展．实例证明模型合理、实用．     

新旧路面联结层沥青与集料洒布量的试验研究

针对沥青路面整治工程中新旧路面因层间联结失效而出现的推移、拥包、网裂和翻浆等早期损坏的问题,通过室内组合试件的剪切试验和渗水试验确定3种沥青胶结料和集料洒布量为试验指标.结果表明,90#基质沥青、SBS改性沥青和改性乳化沥青联结层的抗剪强度与洒布量呈单峰抛物线关系,确定了沥青胶结料和集料的最佳洒布量.同时3种沥青胶结料联结层均不透水,能有效地阻止路面渗水侵蚀旧路面,从而减少沥青路面的水损害.因此,采用90#基质沥青、SBS改性沥青和改性乳化沥青作为沥青路面整治工程中新旧路面联结层将会显著提高路面的使用性能.     

山区桥梁扩大基础施工中的问题及处理

通过对山区桥梁扩大基础施工中常见问题的分析,提出相应的解决方法,对于同类工程具有一定的指导意义。     

亳州枢纽互通区的桥梁设计

亳州枢纽互通是安徽省主干线交叉的重要节点,通过介绍该区桥梁的设计方法和设计思路,其结果可为同类桥梁的设计提供一定的参考.     

Code-aided interference suppression in direct sequence spread spectrum systems with eigenvector sign spreading code

For direct sequence spread spectrum (DSSS) communication systems suffering interference, it is known that code-aided interference suppression technique outperforms all of the previous linear or nonlinear methods. In this paper, we proposed an improved code-aided technique which can improve the system performance greatly by using the eigenvector sign (EVS) spreading sequence which depends on the statistical characteristics of the interference and the thermal noise. Foundation item: the National Natural Science Foundation of China (No. 60772100)