无线传感器网络路由协议研究

网络数据传输离不开路由协议,但是,传统的无线AdHoc网络路由协议却不能适用于无线传感器网络。本文结合工作实际详细分析了几种路由协议或设计新的路由协议,使网络具备更好的可伸缩性和更强的适应网络拓扑变化的能力。     

Evaluating the assumption of independent turning probabilities

Several urban traffic models make the convenient assumption that turning probabilities are independent, meaning that the probability of turning right (or left or going straight through) at the downstream intersection is the same for all travelers on that roadway, regardless of their origin or destination. In reality most travelers make turns according to planned routes from origins to destinations. The research reported here identifies and quantifies the deviations that result from this assumption of independent turning probabilities.An analysis of this type requires a set of reasonably realistic “original” route flows, which were obtained by a static user-equilibrium traffic assignment and an entropy maximization condition for most likely route flows. These flows are compared with those route flows resulting from the Assumption of Independent Turning Probabilities (ITP). A small subnetwork of 3 km by 5 km in Tucson, Arizona, was chosen as a case study. An overall “typical ratio” of 2.2 between original route flows and ITP route flows was obtained. Aggregating route flows to origin–destination flows led to an overall “typical ratio” of 1.7. Such deviations are particularly high for routes that go back-and-forth, reaching a ratio of more than 3 in certain time periods. Substantial deviations for origins and destinations that are on the same border of the subnetwork are also observed in the analyses. In addition, under the ITP assumption, morning rush hour traffic peaking is the same in all directions, while in the original flows some directions do not exhibit a peak in the morning rush hour period. Overall, the conclusion of the paper is that the assumption of independent turning probabilities leads to substantial deviations both at the route level and at the origin–destination level, even for such a small network of the case study. These deviations are particularly detrimental when a network is being modeled and studied for route-based measures of effectiveness such as the number and types of routes passing a point – for monitoring specified vehicles and/or managing detouring strategies.     

京福国道主干线福建省境内西段路线方案技术经济论证

从技术可行性与经济合理性两个方面，对京福国道主干线福建省境内西段路线方案进行分析论证，克服了公路路线规划中通常只进行技术可行性论证的缺陷，为从事道路规划提供一条创新思路。     

生态影响综合评价方法在公路选线中的应用

针对高速公路建设项目的特点,从指标选取入手,采取定量分析的手段,对比研究了两条线路工程建设对生态环境的影响程度。结果表明,用植被覆盖率、生物量、滞洪能力、土壤变化、农田占用、水土流失量等6项指标来定量分析生态影响程度效果较好,采用综合生态影响评价指数法确定线路的舍取是可行的。     

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公路运输路径问题已被证明是高维非线性完全问题,实际中还会增加非流通图约束,使求解更复杂,研究价值较高.鉴于传统遗传算法在求解过程中容易出现早熟收敛、冗余迭代的缺陷,在初始种群生成、交叉变异及搜索操作方面提出改进,设计混沌遗传算法.采用遍历城市顺序的染色体编码,结合随机法与贪心法生成较优初始种群,避免出现大量非可行染色体,提高了后续的遗传效率.接着,执行优先保留交叉和平移变异操作,依次引入局部邻域搜索以及混沌搜索以加快算法收敛,还给出最优解的非连通公路约束满足判据.最后,实验结果验证了新算法的有效性,不但取得了较优解,而且子代种群离散程度较小,收敛性更好.     

高速铁路兰州至张掖三四线越岭隧道选线研究

结合高速铁路兰州至张掖三四线乌鞘岭越岭地形地貌、不良地质、自然保护区等控制因素及相邻既有铁路情况,按照高速铁路"短、直、快"的选线原则之外,从工程地质、环保、经济、安全、工期等方面对地质条件复杂的乌鞘岭越岭方案进行研究,经多方案分析研究,沿既有铁路越岭隧道并行敷设,不但可满足高速铁路选线原则,还可以充分利用既有隧道斜井、竣工地质勘察资料及施工措施经验,解决乌鞘岭工程地质复杂选线问题。     

计算机联锁中非进路调车的软件设计与实现

本文主要讨论了怎样用计算机联锁软件来实现非进路调车作业。     

基于全寿命周期成本理论的山区高速公路路线方案比选

修建山区高速公路规模大、技术要求高、施工环境复杂、投资风险大。此文引入全寿命周期成本理论,针对某山区高速公路某区段在可行性研究阶段提出的A、B两种线路走向方案,进行全寿命周期成本影响因素分析,全寿命周期（30年分析期）费用计算、比较与分析,结果表明,A方案优于B方案,故采用A方案。     

城市轨道交通ATP车载设备测试用例生成方法

根据对城市轨道交通ATP车载设备功能的分析,搭建了模拟车辆外部接口的城市轨道交通ATP车载设备测试环境,确定了测试ATP车载设备的10个安全输入参数和7个非安全输入参数。基于输入参数建立了可变强度覆盖矩阵,并利用回溯搜索算法优化出由20个用例组成的ATP车载设备测试用例集。测试结果表明,给出的测试用例只有穷举测试法的1%,而测试的有效性达90%以上,能够对ATP车载设备功能进行高效和可靠的测试,并大大降低了测试成本,从而验证了ATP车载设备测试用例生成方法的有效性。     

基于单机的搜索优化及实现

搜索引擎已经成为人们获取信息的主要工具.然而基于单机的搜索,尤其是对于特定文件的搜索,其搜索速度不能另人满意.基于此原因,利用Delphi开发工具,开发了一个微型的基于单机的搜索软件,针对特定搜索,进行优化处理,提升搜索速度,满足人们的特定需要.