This paper examines safety impacts of a Pedestrian Countdown Signal (PCS) installed on a busy downtown intersection in San Diego, California. Crossing episodes of over 5000 pedestrians were videotaped and analyzed usi...This paper examines safety impacts of a Pedestrian Countdown Signal (PCS) installed on a busy downtown intersection in San Diego, California. Crossing episodes of over 5000 pedestrians were videotaped and analyzed using multivariate statistical methods. Details of timing of pedestrian crossing as well as information about vehicular traffic and signal timing were carefully coded for each pedestrian. Significant safety benefits of the PCS system were found on the long crossings over a street with high vehicular volumes: most pedestrians were able to effectively increase their walking speed to complete their crossing without committing the exit violation—even if they have already committed the entry violation. However, on the short crossing with light vehicular traffic, PCS was generally ineffective in preventing the entry violations from becoming exit violations. Over there, many pedestrians felt safe enough to walk over a short crossing with no apparent vehicular traffic in sight instead of waiting for a green signal. The length of crossing and volume of interfering vehicular traffic were consistently found the most significant variables affecting the crossing violation rates of different categories of pedestrians. Crossing violation rates were the highest for runners, bicyclists and older males. Crossing violation characteristics were found to be consistent over time.展开更多
After 13 years of negotiations,Chinais now counting down on the World TradeOrganization entry.Chinese Premier Zhu Rongji’s U.S.trip,called by many as an“ice-breaking”one,helped clean major hurdles to China’s
Countdown signals for motorized vehicles,which are intended to ensure safety on the road and regulate motor vehicle speed limits at road intersections,are still considered a relatively novel concept.These signals have...Countdown signals for motorized vehicles,which are intended to ensure safety on the road and regulate motor vehicle speed limits at road intersections,are still considered a relatively novel concept.These signals have been adopted by only a few countries,and the number of cities that use them is limited.This review aims to summarize the effects of countdown signals on traffic safety and efficiency and to determine the consistency and differences of existing research propositions on the matter.Based on the review,considerable research presents evidently different conclusions in the areas of driver red-light running and traffic safety.Particularly,some studies propose that countdown signals reinforce traffic safety,whereas others consider that such signals adversely affect traffic safety.Meanwhile,related literature provides varying conclusions on the aspect of traffic efficiency for vehicle headway.At present,the number of studies conducted regarding the driving behaviors of motorists toward countdown-signalized intersections is insufficient.Accordingly,such inadequate diversity in research causes difficulty in completely assessing the benefits and disadvantages of countdown signals.In this paper,an important future research direction on microcosmic driving psychological and physiological data combined with macro-driving behavior is proposed.展开更多
We propose a novel optical time-to-live （TTL） processing scheme using asymmetric Mech-Zehnder inter-ferometer （AMZI） and Fabry-Perot semiconductor optical amplifier （FP-SOA）. AMZI transfers M TTL pulses into M-1...We propose a novel optical time-to-live （TTL） processing scheme using asymmetric Mech-Zehnder inter-ferometer （AMZI） and Fabry-Perot semiconductor optical amplifier （FP-SOA）. AMZI transfers M TTL pulses into M-1 pulses and two residual pulses with 6-dB power difference. FP-SOA enhances the power difference between the M - 1 pulses to the residual pulses to more than 10 dB. A numerical model is established for verifying the feasibility of this scheme.展开更多
Preparation work for the 2022 Winter Olympic Games is right on schedule At a construction site for the Beijing 2022 Winter Olympic Games in Chongli District, Zhangjiakou City of Hebei Province in north China, about 3,...Preparation work for the 2022 Winter Olympic Games is right on schedule At a construction site for the Beijing 2022 Winter Olympic Games in Chongli District, Zhangjiakou City of Hebei Province in north China, about 3,000 workers are sweating as the final phase of the main buildings of a new complex goes into full swing.展开更多
The mainland NASDAQ-like market is meant to fuel emerging companies,but the risks are high after nearly a decade of delibera- tion,the growth enterprise market (GEM) on the mainland will soon be opened,providing a boo...The mainland NASDAQ-like market is meant to fuel emerging companies,but the risks are high after nearly a decade of delibera- tion,the growth enterprise market (GEM) on the mainland will soon be opened,providing a boon to the country’s start-up companies. Shang Fulin,Chairman of the China Securities Regulatory Committee (CSRC), vowed to push forward the debut of China’s growth board to establish a multi-layer capi- tal market.展开更多
December 13,2001: The BOCOG was established. February 4,2002: The State Council put forth the Regulations on the Protection of Olympic Symbols, which went into effect on April 1, 2002. July 12, 2002: The Beijing Olymp...December 13,2001: The BOCOG was established. February 4,2002: The State Council put forth the Regulations on the Protection of Olympic Symbols, which went into effect on April 1, 2002. July 12, 2002: The Beijing Olympic Action Plan formulated jointly by the Beijing Municipal Government and the BOCOG was promulgated, detailing the main tasks of the preparatory work for the Beijing 2008 Olympic Games. June 11, 2003: The BOCOG Sailing Committee (Qingdao) was set up in Qingdao.展开更多
Beijing Review photographer Wang Xiang attended the launch of the Tiangong-1 unmanned space lab module.Left:The module prepared for launch Bottom (left to right):A medical unit in attendance,and fuelling preparations ...Beijing Review photographer Wang Xiang attended the launch of the Tiangong-1 unmanned space lab module.Left:The module prepared for launch Bottom (left to right):A medical unit in attendance,and fuelling preparations Below:The Long March CZ-2F rocket that will carry展开更多
As the Olympic Games draw closer there are still issues that need to be resolved With a little more than a year before the launch of the Olympic Games in China, preparations seem to be pro- ceeding well. Stadiums are ...As the Olympic Games draw closer there are still issues that need to be resolved With a little more than a year before the launch of the Olympic Games in China, preparations seem to be pro- ceeding well. Stadiums are being built, volunteers are being展开更多
如果你是一名PS2《实况足球》的玩家的话，那么《实况8》中那首激情洋溢的开场音乐是否曾令你为之一震呢?如果之前你还不知道那首乐曲是什么名字的话，那么现在我告诉你吧，那正是选自EUROPE乐队1986年“the final countdown”专辑当中...如果你是一名PS2《实况足球》的玩家的话，那么《实况8》中那首激情洋溢的开场音乐是否曾令你为之一震呢?如果之前你还不知道那首乐曲是什么名字的话，那么现在我告诉你吧，那正是选自EUROPE乐队1986年“the final countdown”专辑当中的这首主打歌曲《the final countdown》。展开更多
文摘This paper examines safety impacts of a Pedestrian Countdown Signal (PCS) installed on a busy downtown intersection in San Diego, California. Crossing episodes of over 5000 pedestrians were videotaped and analyzed using multivariate statistical methods. Details of timing of pedestrian crossing as well as information about vehicular traffic and signal timing were carefully coded for each pedestrian. Significant safety benefits of the PCS system were found on the long crossings over a street with high vehicular volumes: most pedestrians were able to effectively increase their walking speed to complete their crossing without committing the exit violation—even if they have already committed the entry violation. However, on the short crossing with light vehicular traffic, PCS was generally ineffective in preventing the entry violations from becoming exit violations. Over there, many pedestrians felt safe enough to walk over a short crossing with no apparent vehicular traffic in sight instead of waiting for a green signal. The length of crossing and volume of interfering vehicular traffic were consistently found the most significant variables affecting the crossing violation rates of different categories of pedestrians. Crossing violation rates were the highest for runners, bicyclists and older males. Crossing violation characteristics were found to be consistent over time.
文摘After 13 years of negotiations,Chinais now counting down on the World TradeOrganization entry.Chinese Premier Zhu Rongji’s U.S.trip,called by many as an“ice-breaking”one,helped clean major hurdles to China’s
基金support provided by the Shandong Provincial Natural Science Foundation of China(ZR2020MG021 and ZR2022MF332)the Humanities and Social Science Planning Fund of Chinese Ministry of Education(18YJAZH067).
文摘Countdown signals for motorized vehicles,which are intended to ensure safety on the road and regulate motor vehicle speed limits at road intersections,are still considered a relatively novel concept.These signals have been adopted by only a few countries,and the number of cities that use them is limited.This review aims to summarize the effects of countdown signals on traffic safety and efficiency and to determine the consistency and differences of existing research propositions on the matter.Based on the review,considerable research presents evidently different conclusions in the areas of driver red-light running and traffic safety.Particularly,some studies propose that countdown signals reinforce traffic safety,whereas others consider that such signals adversely affect traffic safety.Meanwhile,related literature provides varying conclusions on the aspect of traffic efficiency for vehicle headway.At present,the number of studies conducted regarding the driving behaviors of motorists toward countdown-signalized intersections is insufficient.Accordingly,such inadequate diversity in research causes difficulty in completely assessing the benefits and disadvantages of countdown signals.In this paper,an important future research direction on microcosmic driving psychological and physiological data combined with macro-driving behavior is proposed.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 60572008.
文摘We propose a novel optical time-to-live （TTL） processing scheme using asymmetric Mech-Zehnder inter-ferometer （AMZI） and Fabry-Perot semiconductor optical amplifier （FP-SOA）. AMZI transfers M TTL pulses into M-1 pulses and two residual pulses with 6-dB power difference. FP-SOA enhances the power difference between the M - 1 pulses to the residual pulses to more than 10 dB. A numerical model is established for verifying the feasibility of this scheme.
文摘Preparation work for the 2022 Winter Olympic Games is right on schedule At a construction site for the Beijing 2022 Winter Olympic Games in Chongli District, Zhangjiakou City of Hebei Province in north China, about 3,000 workers are sweating as the final phase of the main buildings of a new complex goes into full swing.
文摘The mainland NASDAQ-like market is meant to fuel emerging companies,but the risks are high after nearly a decade of delibera- tion,the growth enterprise market (GEM) on the mainland will soon be opened,providing a boon to the country’s start-up companies. Shang Fulin,Chairman of the China Securities Regulatory Committee (CSRC), vowed to push forward the debut of China’s growth board to establish a multi-layer capi- tal market.
文摘December 13,2001: The BOCOG was established. February 4,2002: The State Council put forth the Regulations on the Protection of Olympic Symbols, which went into effect on April 1, 2002. July 12, 2002: The Beijing Olympic Action Plan formulated jointly by the Beijing Municipal Government and the BOCOG was promulgated, detailing the main tasks of the preparatory work for the Beijing 2008 Olympic Games. June 11, 2003: The BOCOG Sailing Committee (Qingdao) was set up in Qingdao.
文摘Beijing Review photographer Wang Xiang attended the launch of the Tiangong-1 unmanned space lab module.Left:The module prepared for launch Bottom (left to right):A medical unit in attendance,and fuelling preparations Below:The Long March CZ-2F rocket that will carry
文摘As the Olympic Games draw closer there are still issues that need to be resolved With a little more than a year before the launch of the Olympic Games in China, preparations seem to be pro- ceeding well. Stadiums are being built, volunteers are being
文摘如果你是一名PS2《实况足球》的玩家的话，那么《实况8》中那首激情洋溢的开场音乐是否曾令你为之一震呢?如果之前你还不知道那首乐曲是什么名字的话，那么现在我告诉你吧，那正是选自EUROPE乐队1986年“the final countdown”专辑当中的这首主打歌曲《the final countdown》。
