Analysis of telecommuting behavior and impacts on travel demand and the environment

The discussion of whether, and to what extent, telecommuting can curb congestion in urban areas has spanned more than three decades. This study develops an integrated framework to provide the empirical evidence of the potential impacts of home-based telecommuting on travel behavior, network congestion, and air quality. In the first step, we estimate a telecommuting adoption model using a zero-inflated hierarchical ordered probit model to determine the factors associated with workers’ propensity to adopt telecommuting. Second, we implement the estimated model in the POLARIS activity-based framework to simulate the potential changes in workers’ activity-travel patterns and network congestion. Third, the MOVES mobile source emission simulator and Autonomie vehicle energy simulator are used to estimate the potential changes in vehicular emissions and fuel use in the network as a result of this policy. Different policy adoption scenarios are then tested in the proposed integrated platform. We found that compared to the current baseline situation where almost 12% of workers in Chicago region have flexible working time schedule, in the case when 50% of workers have flexible working time, telecommuting can reduce total daily vehicle miles traveled (VMT) and vehicle hours traveled (VHT) up to 0.69% and 2.09%, respectively. Considering the same comparison settings, this policy has the potential to reduce greenhouse gas and particulate matter emissions by up to 0.71% and 1.14%, respectively. In summary, our results endorse the fact that telecommuting policy has the potential to reduce network congestion and vehicular emissions specifically during rush hours.     

交通可达性与城市经济活动的空间特征分析：以北京市为例

借助开源大数据平台，提出交通可达性及城市经济活动数据采集策略，利用全局常参数和局部变参数回归模型研究北京市六环区域内两者的空间特征.相比于全局模型，局部模型能够较好地刻画交通可达性与城市经济活动间的空间异质性特征.结果表明，私人交通可达性呈现以天安门为中心径向递减的多圈层结构，公共交通呈现轨道交通沿线区域高的特点.交通可达性与经济活动匹配度具有空间非平稳性，空间分离和匹配现象并存.西北部、中部区域空间匹配特征显著，东北部、东部区域次之，西南区域空间分离现象最为严重.丰台及良乡等分离区域，宜重视道路及轨道线网等基础设施建设工作；未来科学城等私人交通匹配，公共交通分离的区域，可考虑修建轨道线路，并增加公交运营服务水平；中关村科学城、北京经济技术开发区等匹配区域，以调整交通运营管理政策为主.     

Application of Lagrangian relaxation approach to α-reliable path finding in stochastic networks with correlated link travel times

This study investigates the important problem of determining a reliable path in a stochastic network with correlated link travel times. First, the distribution of path travel time is quantified by using trip records from GPS probe vehicles. Second, the spatial correlation of link travel time is explicitly considered by using a correlation coefficient matrix, which is incorporated into the α-reliable path problem by Cholesky decomposition. Third, the Lagrangian relaxation based framework is used to handle the α-reliable path problem, by which the intractable problem with a non-linear and non-additive structure can be decomposed into several easy-to-solve problems. Finally, the path-finding performance of this approach is tested on a real-world network. The results show that 15 iterations of calculation can yield a small relative gap between upper and lower bounds of the optimal solution and the average running time is about 5 s for most OD settings. The applicability of α-reliable path finding is validated by a case study.     

Fully autonomous vehicles: analyzing transportation network performance and operating scenarios in the Greater Toronto Area,Canada

Fully autonomous vehicles (AVs) have the potential to considerably change urban mobility in the future. This study simulates potential AV operating scenarios in the Greater Toronto Area (GTA), Canada, and assesses transportation system performance on a regional level. For each scenario, the base capacities of certain types of road links are modified to simulate the theoretical increase in throughput enabled by AV driving behavior. Another scenario examines driverless parking operations in downtown Toronto. Simulation results indicate that the increased attractiveness of freeways relative to other routes leads to slightly increased average travel distance as vehicles divert to access higher capacity road links. Average travel time is found to decrease by up to one-fifth at the 90% AV market penetration level. Concurrently, localized increases in congestion suggest that proactive transportation planning will be needed to mitigate negative consequences of AV adoption, especially in relation to induced demand for personal automobile travel.     

Reconfigurable Communication Processor： A New Approach for Network Processor

As the traditional RISC ASIC/ASSP approach for network processor design can not meet the today‘s requirements, this paper described an alternate approach, Reconfigurable Processing Architecture, to boost the performance to ASIC level while reserve the programmability of the traditional RISC based system. This paper covers both the hardware architecture and the software development environment architecture.     

定时/计数初值求取公式的修正

本文推导了定时/计数初值求取公式,指出利用求补公式计算定时/计数初值的错误。     

CD_3 McAb联合rhIL-2激活的骨髓对白血病细胞杀伤净化作用的研究

目的　探讨CD3单克隆抗体 (CD3McAb)联合重组人白细胞介素 2 (rhIL 2 )激活的骨髓对白血病细胞的杀伤及净化作用。方法　用MTT法检测激活骨髓的细胞毒作用 ;半固体集落培养法观察激活骨髓CFU GM水平和对白血病细胞的净化作用 ;采用间接荧光法测定激活骨髓的免疫标记。结果　CD3McAb与rhIL 2联合激活的骨髓对白血病细胞株K5 6 2、HL 6 0均有明显的杀伤净化作用 ,且优于rhIL 2或CD3McAb单用组 (P <0 .0 5或P <0 .0 1)。rhIL 2和 (或 )CD3McAb对激活骨髓的CFU GM水平无明显影响。CD3McAb +rhIL 2激活的骨髓 ,与活化前及rhIL 2或CD3McAb组相比 ,CD3+ 、CD8+ 、CD1 9+ 、CD2 5+ 、CD38+ 、CD56+ 细胞显著升高。结论　CD3McAb能增强rhIL 2激活的骨髓对白血病细胞的杀伤及净化作用     

血清CPK、LDH、GOT和LAP活性对急性颅脑损伤的诊断价值

对８０例急性颅脑损伤患者血清ＣＰＫ、ＬＤＨ、ＧＯＴ和ＬＡＰ活性进行了测定。结果显示，急性颅脑损伤后血清ＣＰＫ和ＬＤＨ活性显著升高（Ｐ＜０．０５），而血清ＧＯＴ和ＬＡＰＩ活性升高不明显（Ｐ＞０．０５），至于血清酶活性对判断急性颅脑损伤的脑损伤程度和患者预后的价值有待继续探讨。     

A New Fine Damping Method for Solid ESG Rotor

Introduction The spin axis of ESG rotor will move alongclosed trajectories periodically after spin up, thetrajectories enclose either the maximum or theminimum principal axis of inertia depending on theinitial conditions, which is classical polhode mo-tion[1-4]. It is necessary to damp the polhode mo-tion to ensure that the spin axis is aligned with therotor maximum principal axis of inertia for ESGsignal readout. Passive damping and active damp-ing are two common schemes to fulfill this pro…     

多相位信号控制交叉口行人相位设置方法

运用相位组合技术，对行人相位与机动车相位的各种可能的组合进行了研究，提出了二次过街条件下行人相位的设计方法。与传统行人相位设计方法的对比分析表明这种行人相位设计方法缩短了行人过街最短绿灯时间，降低了过街人均延误。