城市路口交通信号单点控制的仿真设计与实现

针对目前城市交通路口车辆拥堵延误现象,路口交通控制方案现场变更的不便与繁琐,采用了适合我国城市单交叉口交通信号控制的方法,设计了交通信号单点控制的仿真系统,利用该仿真系统,可以在控制方案正式下达路口前,通过计算机进行仿真模拟设计并进行评估,将评估符合要求的方案进行实施,仿真结果和实际应用验证了其可行性和有效性。     

基于混沌算法的不对称交通信号模糊控制系统设计

为了改善具有潮汐特性交叉口的交通信号控制,有效降低车辆延误,提出一种混沌算法优化的不对称交通信号模糊控制方法。利用混沌算法的特点优化了模糊控制规则,避免了搜索过程陷入局部最优;为检验该控制方法的性能,采用交叉口车辆平均延误为性能评价指标,并且对控制方法进行了仿真实验。结果表明,经过混沌算法优化的模糊控制器对不对称交通信号的控制能有效减小车辆平均延误,提高路口高峰时段通行能力。     

基于GA-BP神经网络的交叉口短时交通流预测研究

现阶段影响交叉口车辆运行效率的因素主要分为两个方面:其一为受交通信号影响,即实际交通流与交叉口所反应出来的交通信号并不匹配;其二为时间间隔过长,目前短时交通流的普遍预测时长多集中为5-15分钟,过长的时间间隔无法提供有效的信号控制,很容易对最终的数据结果造成不良影响。为提升交叉口短时交通流预测的准确性和实效性,利用科学合理的方式方法对其进行改进有着重要的价值和意义。本文主要对GA-BP神经网络的交叉口短时交通流预测进行研究和分析。     

基于多传感器信息融合的单交叉口信号控制

本文介绍了基于多传感器信息融合技术的单交叉口信号控制方法。首先利用多传感器系统对交通流量进行采集，然后用加权平均的数据融合算法将交通流量数据进行处理，得到更可靠的数据，最后将这些数据作为确定交通信号控制参数的依据，运用公式算出控制参数。进而实现了对单交叉口信号的控制。相对于传统的基于单一传感器信号控制而言，谈方法具有信息的完整性、统一性、多样性和容错性等优点。     

关于城市单交叉口交通信号控制方法的探讨

本文对目前城市交通状况进行了介绍并提出发展城市交通控制的必要性，阐述了目前城市单交叉口交通信号所采用的几种控制方法并分析其特点和不足，探讨了城市单交叉口交通信号控制方法的发展趋势。     

VISSIM和TSIS在交叉口拥挤改善设计中的应用对比

以一个实际交叉口为例,分别从交叉口交通组织和交叉口的信号配时两个方面给出解决交叉口拥挤问题的最优方案,并分别利用VISSIM和TSIS两种仿真软件来对改善后的交叉口运行进行仿真,通过对比两个软件的仿真效果,最终获得最优的交叉口改造方案。     

城市道路T型信号交叉口微观仿真研究

城市道路交叉口是城市道路系统中的重要的组成部分,交叉口的拥堵现象会影响交通的有效运行,提高交叉路口的通行能力对城市的交通有重要意义。利用VISSIM仿真软件对辽宁省鞍山市园林路——二一九路的T型交叉口的高峰交通量、信号配时进行模拟仿真,对仿真结果进行分析,提出优化方案。通过对比优化前后的行车延误、排队长度,验证了优化方案的有效性。优化后的配时方案缓解了交通压力,可以为城市信号交叉口的优化和通行能力的提高提供有效的参考。     

基于交通调查数据的信号优化效果评价研究

交通信号优化是城市交通管理中的一项重要工作,为定量化评估信号控制的优化效果、辅助优化信号控制方案以进一步提升路口的通行能力,基于交通调查的数据建立一套评价信号优化效果的指标体系,体系从路口、路段两个层面对机动车和行人分别构建指标,并重点阐述了各个指标如何利用调查数据计算获得以及各个指标代表的数值意义,最后通过案例验证说明了该评价方法的可行性与有效性。     

西宁市城市道路交叉口信号控制分区研究

依据调查所得的西宁市城市道路交叉口历史交通流量,在简化西宁市城市道路网络图的基础上,提出了信号控制分区的改进型模型和方法,最终得到了西宁市核心区信号控制分7区、8区、9区、10区的方案,为西宁市道路交叉口信号分区控制提供参考。     

一种基于深度学习的道路交叉口车辆排队长度检测方法

<正>随着智能交通系统的逐渐成熟,现在的交通信号控制机可以根据交叉口的实时车流量等交通数据优化信号灯配时,以减少拥堵、降低碳排放。在交通参数中,排队长度表示在交叉口排队的车辆所占道路的长度,不仅可以表征实时交通状态,同时也是评估交叉口拥堵的重要指标。但是排队事件涉及车辆多,车辆运动状态复杂,因此对排队长度的检测一直是该领域的研究热点。利用道路监控视频信息对交叉口排队长度进行检测具有重要的理论意义和实用价值。     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

To serve and promote science development via innovation

CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

Tracing the origin and early radiation of birds——Paleornithologist ZHOU Zhonghe

With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Our Own Devices: Heterotopic Communication, Discourse, and Culture in the Information Society 1

The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests.