The aim of transit-oriented development(TOD)is to create a livable urban environment by improving the integration between land-use and transportation systems.The capital city of Ethiopia,Addis Ababa,aims to promote a ...The aim of transit-oriented development(TOD)is to create a livable urban environment by improving the integration between land-use and transportation systems.The capital city of Ethiopia,Addis Ababa,aims to promote a sustainable transportation system by launching its first light rail transit(LRT)network to control the current pattern of increased congestion and the need for mass transport.Planning for TOD around existing transit stations helps achieve improved transit choice and encourages local economic development.Therefore,this article proposes a methodology to quantitatively measure the existing TOD in terms of a TOD index within the walkable distance of transit nodes by measuring the criteria that define TOD levels.The TOD index is calculated for areas of 22 stations on the East-West LRT line of Addis Ababa.Depending on the value of the TOD index,certain stations are identified to have a potential TOD but poor transit accessibility.With these results,the recommendation to improve TOD planning can become accurate for each station,depending on its relevant factors.Such results also help identify each station’s potential for TOD planning and its improvements toward future local developments.展开更多
Rapid transit(RT)systems are becoming increasingly attractive in the developing world as they improve transportation and mobility conditions in urban areas,reduce motorization impacts and offer high quality,yet cost e...Rapid transit(RT)systems are becoming increasingly attractive in the developing world as they improve transportation and mobility conditions in urban areas,reduce motorization impacts and offer high quality,yet cost effective services to travelers.Light rail transit(LRT)and bus rapid transit(BRT)are RT systems that combine high capacity with relatively low investment costs,and as such,they are preferred in developing countries over regular metro systems.This paper investigates traveler preferences over alternative,planned rapid transit options for the city of Multan,Pakistan.The analysis is based on a household information survey with over 2300 questionnaires completed via personal interviews.Intention to pay for improved PT services and choice between LRT and BRT systems are investigated,using appropriate econometric models.Findings of this study can assist in better understanding the factors and their effect on choice between BRT and LRT in developing countries.Results show that potential travelers,who prefer LRT are willing to pay more for better public transport services.On the other hand,commuters and elders express a taste towards BRT implementation.Based on model outputs policy makers can develop targeted marketing policies in order to promote BRT/LRT implementation andattract candidate travelers from different groups,improving the possibility that users would support a BRT or LRT project.展开更多
超宽带(Ultra Wide Band,UWB)室内定位系统的定位性能主要受信号非视距(None Line Of Sight,NLOS)传播影响。为此该文提出一种基于信道统计量(Channel Statistics Information,CSI)的信道NLOS状态检测法。该方法首先在IEEE802.15.4a信...超宽带(Ultra Wide Band,UWB)室内定位系统的定位性能主要受信号非视距(None Line Of Sight,NLOS)传播影响。为此该文提出一种基于信道统计量(Channel Statistics Information,CSI)的信道NLOS状态检测法。该方法首先在IEEE802.15.4a信道模型下对均方根时延扩展和平均超量延迟的概率分布函数进行建模,作为信道标准分布。再以信道瞬时分布与标准分布间的KL散度为检验统计量做似然比检验(Likelihood Ratio Test,LRT)来鉴别信道状态。同时提出一种基于LRT的定位算法LRT-Chan算法。该算法能有效利用受NLOS污染的测距数据提高定位精度。仿真结果表明:LRT信道状态检测法在全部UWB信道中都能获得较高检测准确率;在定位锚点(Anchor Node,AN)分布不理想的NLOS环境中LRT-Chan算法也能取得较高定位精度。展开更多
针对金融时间序列普遍存在自相关性、杠杆效应、尖峰厚尾等典型事实,运用基于杠杆效应的GARCH模型,构建铜期货市场收益序列具有典型事实的动态风险测度模型:VaR-AR(m)-EGARCH(p,q)和VaR-AR(m)-TGARCH(p,q),再通过上海期货交易所(SHFE)...针对金融时间序列普遍存在自相关性、杠杆效应、尖峰厚尾等典型事实,运用基于杠杆效应的GARCH模型,构建铜期货市场收益序列具有典型事实的动态风险测度模型:VaR-AR(m)-EGARCH(p,q)和VaR-AR(m)-TGARCH(p,q),再通过上海期货交易所(SHFE)铜期货对所建模型进行实证分析,并运用Back-testing中的LRT(Likelihood Ratio Test)方法,对铜期货市场风险测度模型准确性和可靠性进行实证检验。实证结果表明,基于非对称GARCH的铜期货市场动态风险度量模型,能够有效捕获铜期货市场的典型事实,同时还能够准确测度具有杠杆效应的铜期货市场的动态风险,也能加强对金融市场动态风险预测能力。展开更多
文摘The aim of transit-oriented development(TOD)is to create a livable urban environment by improving the integration between land-use and transportation systems.The capital city of Ethiopia,Addis Ababa,aims to promote a sustainable transportation system by launching its first light rail transit(LRT)network to control the current pattern of increased congestion and the need for mass transport.Planning for TOD around existing transit stations helps achieve improved transit choice and encourages local economic development.Therefore,this article proposes a methodology to quantitatively measure the existing TOD in terms of a TOD index within the walkable distance of transit nodes by measuring the criteria that define TOD levels.The TOD index is calculated for areas of 22 stations on the East-West LRT line of Addis Ababa.Depending on the value of the TOD index,certain stations are identified to have a potential TOD but poor transit accessibility.With these results,the recommendation to improve TOD planning can become accurate for each station,depending on its relevant factors.Such results also help identify each station’s potential for TOD planning and its improvements toward future local developments.
基金part of a consultancy project funded by the Government of Punjab and the Punjab Metrobus Authority(www.pma.punjab.gov.pk)。
文摘Rapid transit(RT)systems are becoming increasingly attractive in the developing world as they improve transportation and mobility conditions in urban areas,reduce motorization impacts and offer high quality,yet cost effective services to travelers.Light rail transit(LRT)and bus rapid transit(BRT)are RT systems that combine high capacity with relatively low investment costs,and as such,they are preferred in developing countries over regular metro systems.This paper investigates traveler preferences over alternative,planned rapid transit options for the city of Multan,Pakistan.The analysis is based on a household information survey with over 2300 questionnaires completed via personal interviews.Intention to pay for improved PT services and choice between LRT and BRT systems are investigated,using appropriate econometric models.Findings of this study can assist in better understanding the factors and their effect on choice between BRT and LRT in developing countries.Results show that potential travelers,who prefer LRT are willing to pay more for better public transport services.On the other hand,commuters and elders express a taste towards BRT implementation.Based on model outputs policy makers can develop targeted marketing policies in order to promote BRT/LRT implementation andattract candidate travelers from different groups,improving the possibility that users would support a BRT or LRT project.
文摘超宽带(Ultra Wide Band,UWB)室内定位系统的定位性能主要受信号非视距(None Line Of Sight,NLOS)传播影响。为此该文提出一种基于信道统计量(Channel Statistics Information,CSI)的信道NLOS状态检测法。该方法首先在IEEE802.15.4a信道模型下对均方根时延扩展和平均超量延迟的概率分布函数进行建模,作为信道标准分布。再以信道瞬时分布与标准分布间的KL散度为检验统计量做似然比检验(Likelihood Ratio Test,LRT)来鉴别信道状态。同时提出一种基于LRT的定位算法LRT-Chan算法。该算法能有效利用受NLOS污染的测距数据提高定位精度。仿真结果表明:LRT信道状态检测法在全部UWB信道中都能获得较高检测准确率;在定位锚点(Anchor Node,AN)分布不理想的NLOS环境中LRT-Chan算法也能取得较高定位精度。
文摘脉冲超宽带(impulse radio ultra wide band,IR-UWB)测距定位系统中,信号的非视距(non-line-of-sight,NLOS)传播检测及在定位算法中给予误差矫正是提升定位性能的主要方法。为此提出了一种基于信道统计量(channel statistic information,CSI)——峭度(kurtosis,K)和均方根时延扩展(root mean square delay spread,RMS)联合似然比检验(Likelihood ratio test,LRT)区分NLOS状态的算法。该算法首先对IEEE802.15.4a信道的K和RMS的概率分布进行建模,作为标准信道分布;然后对信道的瞬间分布和标准分布的KL散度做LRT检测信道状态。最后利用信道检测结果,提出了一种基于LRT的Taylor(LRT-Taylor)定位算法。仿真结果表明:K和RMS联合的LRT检测法鉴别所有UWB信道环境都有较高的准确率;在移动端(mobile terminal,MT)与锚点(anchor node,AN)间为较复杂的NLOS环境时,LRT-Taylor算法也能获得较高的定位精度。
文摘针对金融时间序列普遍存在自相关性、杠杆效应、尖峰厚尾等典型事实,运用基于杠杆效应的GARCH模型,构建铜期货市场收益序列具有典型事实的动态风险测度模型:VaR-AR(m)-EGARCH(p,q)和VaR-AR(m)-TGARCH(p,q),再通过上海期货交易所(SHFE)铜期货对所建模型进行实证分析,并运用Back-testing中的LRT(Likelihood Ratio Test)方法,对铜期货市场风险测度模型准确性和可靠性进行实证检验。实证结果表明,基于非对称GARCH的铜期货市场动态风险度量模型,能够有效捕获铜期货市场的典型事实,同时还能够准确测度具有杠杆效应的铜期货市场的动态风险,也能加强对金融市场动态风险预测能力。
