In this paper, traffic environment quality assessment is achieved by applying fuzzy mathematics methods. Set up an assessment system, determine assessment criterion, formulate membership function, make program designs...In this paper, traffic environment quality assessment is achieved by applying fuzzy mathematics methods. Set up an assessment system, determine assessment criterion, formulate membership function, make program designs and conduct example analysis. The evaluation result is consistent with the real case. So that the method of the fuzzy evaluation is a good one for the environment quality assessment.展开更多
The accidental release of a flammable gas on a road can result in a vapour cloud explosion (VCE). Such VCEs generate a blast wave that propagates away from the explosion, potentially damaging nearby structures. The TN...The accidental release of a flammable gas on a road can result in a vapour cloud explosion (VCE). Such VCEs generate a blast wave that propagates away from the explosion, potentially damaging nearby structures. The TNO Multi-Energy Method is commonly used for a simplified estimate of the blast load resulting from a VCE. The method characterises the severity and duration of the blast wave using a case-specific strength class and combustion energy (which the method relates to the gas volume of the equivalent blast source). However, no specific guidelines for estimating the strength class in urban roads or related settings (such as carparks) are currently available in the literature. This makes implementing the method in such scenarios challenging and imprecise. The authors’ work used computational fluid dynamics (CFD) to evaluate multiple gas explosion scenarios and proposed recommendations for determining the strength class and gas volume at the blast source. These scenarios comprised a group of vehicles engulfed by a stoichiometric propane-air cloud. It was concluded that the strength class could be reasonably estimated based on the number of vehicles in the transverse direction. Furthermore, the guidance for estimating the gas volume at the equivalent blast source was based on the critical gas volume, after which no further enhancement of overpressure was obtained. The recommendations were implemented in several scenarios and compared with corresponding CFD analyses. The results showed very good agreement for predicting impulse. Predicting overpressure was affected by the inherent asymmetry of the scenarios, although it was possible to achieve acceptable and conservative results.展开更多
With the development of socio-economic conditions,comprehensive improvements in residential environments,and evolving family values among the elderly,mobility issues for senior citizens have become a prominent social ...With the development of socio-economic conditions,comprehensive improvements in residential environments,and evolving family values among the elderly,mobility issues for senior citizens have become a prominent social concern in China.Aging urban districts characterized by concentrated elderly populations exhibit significant environmental challenges and urgently need age-friendly infrastructure updates.This study conducted a comprehensive review of domestic and international literature related to the age-friendly renovation of the non-motorized traffic environment and systematically analyzed research trends and existing gaps.Furthermore,it investigated the pedestrian spaces in Tianjin’s aging urban districts and delineated multifaceted spatial challenges.Simultaneously,in-depth demographic analysis of the aging population in Tianjin’s four central urban districts informed the strategic selection of nine sub-districts—comprising the two sub-districts with the highest aging population rates in each district,along with Wanxing sub-district,which hosts the city’s largest elderly population.Through random interviews with 40 senior residents in those sub-districts,the multi-level environmental needs of elderly individuals in these aging urban neighborhoods were comprehensively explored and categorized.Ultimately,by comparing the environmental needs of the elderly population with the current urban landscape,this study accurately identified the key elements for the age-appropriate renewal of the non-motorized traffic environment.Furthermore,targeted strategic intervention plans that address the issue of infrastructure adaptation in aging urban areas are proposed.展开更多
By analyzing and comparing the existing methods for the division of urban economic region, this paper supplemented and developed the breaking point theory. In this model, put forward for the first time using ＂the spa...By analyzing and comparing the existing methods for the division of urban economic region, this paper supplemented and developed the breaking point theory. In this model, put forward for the first time using ＂the space-time distance＂ to replace ＂the space- linear distance＂ and ＂the city comprehensiveness quality- fuzzy comprehensive assessment Index＂ to ＂the urban population or GDP＇. Set up the algorithm of including ＂the space- time distance＂ and the city radiation scope changed with the changes of traffic conditions. Thus has realized ＂dynamically＂ tracing of the city radiation scope influenced by the traffic conditions. Taking Yichang city as an example, the paper analyzed the city function localization in the times of new traffic environments. Because China＇s cities are at the times of the traffic great changes, therefore, the method and the main conclusions of this paper have some methodology guiding sense to the majority cities of deffernt country to re-position.展开更多
Environmental stress model is proposed as an effective tool to the analysis and evaluation of navigational safety in ports and waterways. Marine traffic simulations are carried out in a virtual port area with various ...Environmental stress model is proposed as an effective tool to the analysis and evaluation of navigational safety in ports and waterways. Marine traffic simulations are carried out in a virtual port area with various arrangements and conditions. Calculations of stress values and traffic volume criteria are illustrated. The simulation results provide a valuable hint for safety management of vessel traffic. The model provides quantitative information and helps administrators in decision making to achieve desired safety level and improve the efficiency of vessel traffic in ports and waterways.展开更多
为了有效缓解空中航路网络中大规模航空器集群排放引发的环境问题,研究提出一种基于聚合网络交通流的空中交通绿色优化方法。以航空器集群聚合形成的网络交通流为研究对象,构建空中航路网络交通流动力学模型,用以描述管制干预下网络交...为了有效缓解空中航路网络中大规模航空器集群排放引发的环境问题,研究提出一种基于聚合网络交通流的空中交通绿色优化方法。以航空器集群聚合形成的网络交通流为研究对象,构建空中航路网络交通流动力学模型,用以描述管制干预下网络交通流的动态演化行为。在此基础上,以最小化航空排放所致的全球绝对温变潜力(Absolute Global Temperature Potential, AGTP)为目标,构建空中航路网络交通流绿色优化模型。该模型的维度与大规模航空器集群数量无关,而取决于有限的空域单元数量,显著降低了建模维度。此外,为了进一步削减计算复杂度,通过引入辅助变量约束的方法,将原本的非线性规划问题转化为混合整数线性规划(Mixed-Integer Linear Programming, MILP)问题,并借助Cplex进行求解。最后,以华东区域5个高空管制扇区构成的航路网络为实例,对所提方法开展验证。实例分析结果显示:网络交通流动力学模型能够较好地描述空中交通的动态演化行为,平均推演误差为4.55%;网络交通流绿色管控模型可有效降低航空排放的环境影响,在25 a、50 a、100 a的时间影响尺度下,AGTP分别降低38.73%、47.62%、47.65%。展开更多
文摘In this paper, traffic environment quality assessment is achieved by applying fuzzy mathematics methods. Set up an assessment system, determine assessment criterion, formulate membership function, make program designs and conduct example analysis. The evaluation result is consistent with the real case. So that the method of the fuzzy evaluation is a good one for the environment quality assessment.
文摘The accidental release of a flammable gas on a road can result in a vapour cloud explosion (VCE). Such VCEs generate a blast wave that propagates away from the explosion, potentially damaging nearby structures. The TNO Multi-Energy Method is commonly used for a simplified estimate of the blast load resulting from a VCE. The method characterises the severity and duration of the blast wave using a case-specific strength class and combustion energy (which the method relates to the gas volume of the equivalent blast source). However, no specific guidelines for estimating the strength class in urban roads or related settings (such as carparks) are currently available in the literature. This makes implementing the method in such scenarios challenging and imprecise. The authors’ work used computational fluid dynamics (CFD) to evaluate multiple gas explosion scenarios and proposed recommendations for determining the strength class and gas volume at the blast source. These scenarios comprised a group of vehicles engulfed by a stoichiometric propane-air cloud. It was concluded that the strength class could be reasonably estimated based on the number of vehicles in the transverse direction. Furthermore, the guidance for estimating the gas volume at the equivalent blast source was based on the critical gas volume, after which no further enhancement of overpressure was obtained. The recommendations were implemented in several scenarios and compared with corresponding CFD analyses. The results showed very good agreement for predicting impulse. Predicting overpressure was affected by the inherent asymmetry of the scenarios, although it was possible to achieve acceptable and conservative results.
文摘With the development of socio-economic conditions,comprehensive improvements in residential environments,and evolving family values among the elderly,mobility issues for senior citizens have become a prominent social concern in China.Aging urban districts characterized by concentrated elderly populations exhibit significant environmental challenges and urgently need age-friendly infrastructure updates.This study conducted a comprehensive review of domestic and international literature related to the age-friendly renovation of the non-motorized traffic environment and systematically analyzed research trends and existing gaps.Furthermore,it investigated the pedestrian spaces in Tianjin’s aging urban districts and delineated multifaceted spatial challenges.Simultaneously,in-depth demographic analysis of the aging population in Tianjin’s four central urban districts informed the strategic selection of nine sub-districts—comprising the two sub-districts with the highest aging population rates in each district,along with Wanxing sub-district,which hosts the city’s largest elderly population.Through random interviews with 40 senior residents in those sub-districts,the multi-level environmental needs of elderly individuals in these aging urban neighborhoods were comprehensively explored and categorized.Ultimately,by comparing the environmental needs of the elderly population with the current urban landscape,this study accurately identified the key elements for the age-appropriate renewal of the non-motorized traffic environment.Furthermore,targeted strategic intervention plans that address the issue of infrastructure adaptation in aging urban areas are proposed.
文摘By analyzing and comparing the existing methods for the division of urban economic region, this paper supplemented and developed the breaking point theory. In this model, put forward for the first time using ＂the space-time distance＂ to replace ＂the space- linear distance＂ and ＂the city comprehensiveness quality- fuzzy comprehensive assessment Index＂ to ＂the urban population or GDP＇. Set up the algorithm of including ＂the space- time distance＂ and the city radiation scope changed with the changes of traffic conditions. Thus has realized ＂dynamically＂ tracing of the city radiation scope influenced by the traffic conditions. Taking Yichang city as an example, the paper analyzed the city function localization in the times of new traffic environments. Because China＇s cities are at the times of the traffic great changes, therefore, the method and the main conclusions of this paper have some methodology guiding sense to the majority cities of deffernt country to re-position.
文摘Environmental stress model is proposed as an effective tool to the analysis and evaluation of navigational safety in ports and waterways. Marine traffic simulations are carried out in a virtual port area with various arrangements and conditions. Calculations of stress values and traffic volume criteria are illustrated. The simulation results provide a valuable hint for safety management of vessel traffic. The model provides quantitative information and helps administrators in decision making to achieve desired safety level and improve the efficiency of vessel traffic in ports and waterways.
文摘为了有效缓解空中航路网络中大规模航空器集群排放引发的环境问题,研究提出一种基于聚合网络交通流的空中交通绿色优化方法。以航空器集群聚合形成的网络交通流为研究对象,构建空中航路网络交通流动力学模型,用以描述管制干预下网络交通流的动态演化行为。在此基础上,以最小化航空排放所致的全球绝对温变潜力(Absolute Global Temperature Potential, AGTP)为目标,构建空中航路网络交通流绿色优化模型。该模型的维度与大规模航空器集群数量无关,而取决于有限的空域单元数量,显著降低了建模维度。此外,为了进一步削减计算复杂度,通过引入辅助变量约束的方法,将原本的非线性规划问题转化为混合整数线性规划(Mixed-Integer Linear Programming, MILP)问题,并借助Cplex进行求解。最后,以华东区域5个高空管制扇区构成的航路网络为实例,对所提方法开展验证。实例分析结果显示:网络交通流动力学模型能够较好地描述空中交通的动态演化行为,平均推演误差为4.55%;网络交通流绿色管控模型可有效降低航空排放的环境影响,在25 a、50 a、100 a的时间影响尺度下,AGTP分别降低38.73%、47.62%、47.65%。
