一类奇异积分算子与无界连续函数逼近

利用扩展乘数法建立了Мцракъян算子逼近全实轴上任意无界连续函数的收敛性定理,给出了具有一般性的结论,从而推广了前人的若干重要定理．     

基于开关函数的电压型四象限变流器及控制系统仿真

建立了基于开关函数的电压型四象限变流器数学模型,结合瞬态电流控制,搭建了整个基于开关函数的四象限变流器及控制系统的仿真模型,并在MATLAB环境下进行了稳态及动态的仿真,验证了瞬态电流控制是一种较好的控制等路.     

Dynamic modeling and control of taxi services in large-scale urban networks: A macroscopic approach

Taxis are increasingly becoming a prominent mobility mode in many major cities due to their accessibility and convenience. The growing number of taxi trips and the increasing contribution of taxis to traffic congestion are cause for concern when vacant taxis are not distributed optimally within the city and are unable to find unserved passengers effectively. A way of improving taxi operations is to deploy a taxi dispatch system that matches the vacant taxis and waiting passengers while considering the search friction dynamics. This paper presents a network-scale taxi dispatch model that takes into account the interrelated impact of normal traffic flows and taxi dynamics while optimizing for an effective dispatching system. The proposed model builds on the concept of the macroscopic fundamental diagram (MFD) to represent the dynamic evolution of traffic conditions. The model considers multiple taxi service firms operating in a heterogeneously congested city, where the city is assumed to be partitioned into multiple regions each represented with a well-defined MFD. A model predictive control approach is devised to control the taxi dispatch system. The results show that lack of the taxi dispatching system leads to severe accumulation of unserved taxi passengers and vacant taxis in different regions whereas the dispatch system improves the taxi service performance and reduces traffic congestion by regulating the network towards the undersaturated condition. The proposed framework demonstrates sound potential management schemes for emerging mobility solutions such as fleet of automated vehicles and demand-responsive transit services.     

铁路基础设施建设加载国防功能的思考

简述了铁路基础设施建设加载囯防功能在路网规划和设计前期工作中的工作要点,以及当前投资建设项目加载国防功能过程中存在的投资未单列、国防需求定性不定量、国防意识淡薄等突出问题,提出了调整或制定相关的经济政策、建立健全领导体制和工作机制等建议。     

Use of duration models for predicting vehicular delay at a US/Canadian border crossing

Delays caused by congestion at the US/Canadian border crossing between Washington state and British Columbia have underscored the need for some sort of intervention. One obvious congestion-mitigation measure would be to estimate delay times and then relay this information to motorists so that they could select among alternative border crossing sites, or delay their trips. This paper applies duration models to estimate vehicular delay and demonstrates the usefulness of such models as a basis for a fully automated motorist information system. The paper also explores the flexibility of duration models, in providing estimates of vehicle delay, by using alternate parametric forms and assessing prediction accuracy.     

关于负系数解析函数的一个子类

主要根据单位开圆盘内单叶解析函数的性质,讨论了负系数解析函数的一个子族G(λ,α)中函数属于G(λ,α)的必要条件、系数估计及畸变定理,同时也给出了此函数族的包含关系和凸性.     

随机-区间混合不确定性下FRP桁架桥多尺度可靠性分析

桁架结构是FRP材料在新建桥梁结构中应用的主要形式之一,然而由于缺乏设计规范、分析方法和数据信息等,FRP桥梁结构存在真实安全度模糊的问题.针对FRP桁架桥在细-宏观尺度参数均存在不确定性,且同时存在随机不确定性和由于概率信息缺乏而表达为非概率不确定性的问题,提出一种多尺度混合可靠性分析方法,该方法能够处理在概率和非概...     

公交枢纽内多线路车辆实时调度优化方法研究

公交枢纽内多线路车辆的实时调度能够提高换乘效率,特别对于已经进行了发车优化的公交线路而某些车辆到达出现延误的情况。根据线路的延迟到达时间和换乘客流量等因素建立了公交枢纽内多线路车辆的实时调度优化问题模型,提出了基于整个系统费用最小的优化目标函数,并运用随机扰动梯度近似算法对问题进行求解。最后结合算例分析了本文方法的应用。     

强奇异积分算子及其交换子在Hardy型空间上的有界性

当核K(x,y)在x=y附近满足较高的奇性时,得到强奇异Calderón-zygmund积分算子Tf(x)=∫K(x,y)f(y)dy的有界性及它与Lipschitz函数b∈Lipβ(Rn)生成的交换子[b,T]在某类Hardy型空间Hbpm,s(Rn)上的有界性。     

深海潜水器载人舱结构健康监测评估系统研究

深海载人潜水器是海洋资源勘探和开发的重要装备,其载人舱球壳是保证下潜人员安全及舱内设备正常工作的基础,为及时掌握载人舱球壳在长期使用过程中的安全状态,对其进行健康监测与实时评估十分必要.本文首先对4500m潜水器载人舱球壳进行受力分析;然后根据球壳特征和监测需求设计载人舱球壳健康监测评估系统;对钛合金蠕变对系统测量结果的影响进行了研究分析,研究结果表明在最大工作压力下蠕变对测量结果的影响小于1％;最后给出了结构安全性评估算法函数,并用球壳静水外压试验数据对结构评估算法进行验证.