Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records cover...Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of -21.2mm/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.展开更多
Multi-objective optimization of urban bus network can help improve operation efficiency of the transit system and develop strategies for reducing urban traffic congestion in China. The work used cumulative prospect th...Multi-objective optimization of urban bus network can help improve operation efficiency of the transit system and develop strategies for reducing urban traffic congestion in China. The work used cumulative prospect theory, currently the most influential model for decision under uncertainty,to optimize urban bus network. To achieve the research objective, the work developed the theoretical framework of urban bus network optimization, including optimization principle, optimization objectives and constraints. Furthermore, optimization objectives could comprehensively reflect expectations of passengers and bus companies from the dimension of time, space and value. It is more scientific and reasonable compared with only one stakeholder or dimension alone in the previous studies. In addition,the technique for order preference by similarity to ideal solution(TOPSIS) was used to determine the positive and negative ideal alternative. The correlations between the optimization alternatives and the ideal alternatives were estimated by grey relational analysis simultaneously. The cumulative prospect theory(CPT) was used to determine the best alternative by comparing comprehensive prospect value of every alternative, accurately describing decision-making behavior compared with expected utility theory in actual life. Finally, Case of Xi'an showed that the method can better adjust the bus network,and the optimization solution is more reasonable to meet the actual needs.展开更多
文摘Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of -21.2mm/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.
基金supported by China’s National Key Basic Research Program under Grant No.2012CB725400China’s National Natural Science Fund Key Research Program under Grant No.51338003+2 种基金Key Cultivating Plan of Xi’an University of Architecture and Technology for Discipline Construction under Grant No.XK201213Talents Training Fund Program of Xi’an University of Architecture and Technology for Cultivating Discipline Construction under Grant No.XK201101Youth Talent Fund of Xi’an University of Architecture and Technology under Grant No.DB01138
文摘Multi-objective optimization of urban bus network can help improve operation efficiency of the transit system and develop strategies for reducing urban traffic congestion in China. The work used cumulative prospect theory, currently the most influential model for decision under uncertainty,to optimize urban bus network. To achieve the research objective, the work developed the theoretical framework of urban bus network optimization, including optimization principle, optimization objectives and constraints. Furthermore, optimization objectives could comprehensively reflect expectations of passengers and bus companies from the dimension of time, space and value. It is more scientific and reasonable compared with only one stakeholder or dimension alone in the previous studies. In addition,the technique for order preference by similarity to ideal solution(TOPSIS) was used to determine the positive and negative ideal alternative. The correlations between the optimization alternatives and the ideal alternatives were estimated by grey relational analysis simultaneously. The cumulative prospect theory(CPT) was used to determine the best alternative by comparing comprehensive prospect value of every alternative, accurately describing decision-making behavior compared with expected utility theory in actual life. Finally, Case of Xi'an showed that the method can better adjust the bus network,and the optimization solution is more reasonable to meet the actual needs.
