The fund budget of multipurpose transit smart card systems is studied by stochastic programming to assign limited funds to different applications reasonably. Under the constraints of a gross fund, models of chance-con...The fund budget of multipurpose transit smart card systems is studied by stochastic programming to assign limited funds to different applications reasonably. Under the constraints of a gross fund, models of chance-constrained and dependentchance for the fund budget of multipurpose transit smart card systems are established with application scale and social demand as random variables, respectively aiming to maximize earnings and satisfy the service requirements the furthest; and the genetic algorithm based on stochastic simulation is adopted for model solution. The calculation results show that the fund budget differs greatly with different system objectives which can cause the systems to have distinct expansibilities, and the application scales of some applications may not satisfy user demands with limited funds. The analysis results indicate that the forecast of application scales and application future demands should be done first, and then the system objective is determined according to the system mission, which can help reduce the risks of fund budgets.展开更多
The novel method to analyze metallic structure corrosion status was proposed in the presence of stray current in DC mass transit systems. Firstly, the characteristic parameter and the influence parameters for the corr...The novel method to analyze metallic structure corrosion status was proposed in the presence of stray current in DC mass transit systems. Firstly, the characteristic parameter and the influence parameters for the corrosion status were determined. Secondly, an experimental system was established for simulating the corrosion process within the stray current interference. Then, a predictive model for the corrosion status was built, using a support vector machine(SVM) method and experimental data. The data were divided into two sets, including training set and testing set. The training set was used to generate the SVM model and the testing set was used to evaluate the predictive performance of the SVM model. The results show that the relationship between the characteristic parameter and the influence parameters is nonlinear and the SVM model is suitable for predicting the corrosion status.展开更多
Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when int...Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when interacting with the physical world, hence exact equivalence is restrictive and not robust. Using Baire met- ric, a generalized framework of transition system approximation is proposed by developing the notions of approximate language equivalence and approximate singleton failures （SF） equivalence. The framework takes the traditional exact equivalence as a special case. The approximate language equivalence is coarser than the approximate Slc equivalence, just like the hierarchy of the exact ones. The main conclusion is that the two approximate equiva- lences satisfy the transitive property, consequently, they can be successively used in transition system approximation.展开更多
Strategic emerging industries represent the forefront of the new technological revolution and industrial transformation,serving as a critical domain for China to cultivate new growth drivers and establish competitive ...Strategic emerging industries represent the forefront of the new technological revolution and industrial transformation,serving as a critical domain for China to cultivate new growth drivers and establish competitive advantages.The development of these industries has become a major strategy for leading countries to attain competitive advantages in the new wave of economic and technological advancement.The ongoing energy revolution is driving the transition of traditional energy systems toward green and low-carbon models,while simultaneously fostering emerging industrial clusters such as new energy equipment manufacturing,energy storage,and energy internet.Energy companies are accelerating the deployment of innovative models that integrate new and traditional energy systems through technological and business model innovation.This study systematically analyzes the current status,trends,opportunities,and challenges faced by energy companies venturing into strategic emerging industries.The findings aim to guide energy companies in navigating the dual imperatives of energy transition and industrial upgrading,thereby contributing to sustainable development and global competitiveness.展开更多
Let （X, f ） be a topological dynamical system, where X is a nonempty compact and metrizable space with the metric d and f ：X →X is a continuous map. For any integer n≥2, denote the product space by X（n）=X ...Let （X, f ） be a topological dynamical system, where X is a nonempty compact and metrizable space with the metric d and f ：X →X is a continuous map. For any integer n≥2, denote the product space by X（n）=X · · · × X｜ {z }n times . We say a system （X, f ） is generally distributionally n-chaotic if there exists a residual set D ？X（n） such that for any point x=（x1, · · · , xn）∈D, lim inf k→∞#（{i：0≤i≤k-1, min{d（fi（xj）, fi（xl））：1≤j 6=l≤n}〈δ0}） k=0 for some real numberδ0〉0 and lim sup k→∞#（{i：0≤i≤k-1, max{d（fi（xj）, fi（xl））：1≤j 6=l≤n}〈δ}） k=1 for any real number δ 〉 0, where #（·） means the cardinality of a set. In this paper, we show that for each integer n ≥ 2, there exists a system （X,σ） which satisfies the following conditions： （1） （X,σ） is transitive;（2） （X,σ） is generally distributionally n-chaotic, but has no distributionally （n＋1）-tuples;（3） the topological entropy of （X,σ） is zero and it has an IT-tuple.展开更多
The floating population has become the main driver of urban population excessive growth in China＇s mega cities. Urban transit system （UTS） is a significant factor in population spatial distributions within urban ar...The floating population has become the main driver of urban population excessive growth in China＇s mega cities. Urban transit system （UTS） is a significant factor in population spatial distributions within urban areas, especially rapid and high-capacity transit systems. This paper analyzes the causal effects of the extension of expressways and subways between 2000 and 2010 in the Beijing Metropolitan Area （BMA）, focusing on the group differences between the local residents and the floating population. Due to the endogeneity of transportation improvements and population growth, Instrumental Variable （IV） regression model is applied to avoid this problem. The results show the local residents increased in the inner suburbs but decreased in the city center, while the floating population increased in the majority areas. IV regression results show that the extension of urban transit systems had statistically significant impacts on population growth across the BMA, The results also show that the extension of urban subway system had more effects on the floating population than the local residents across the BMA. It is mainly caused by the rather low fare of urban subway system. This implies that the excessive subsidy on urban subway system could result in ex- cessive floating population growth and residential differentiation, even residential segregation Hence, it is necessary to plan and design reasonable and scientific urban transit systems in order to advance reasonable population size and promote residential integration. Moreover, the regional analysis shows that the effects of urban transportation improvements on the local residents are not statistically significant in the inner suburbs. It implies that urban transportation improvements had limited effects on inducing people to move to suburban areas and controlling center city＇s population in Beijing. Therefore, it should be stressed the differenti- ated effects of urban transportation improvements on population distribution in the process of urban planning and population control.展开更多
Checking if the implementations conform to the requirement models is challenging. Most existing techniques for consistency checking either focus on requirement models（e.g., requirements consistency checking）, or on ...Checking if the implementations conform to the requirement models is challenging. Most existing techniques for consistency checking either focus on requirement models（e.g., requirements consistency checking）, or on the implementations（e.g., code-based testing） only. In this paper we propose an approach to checking behavioral consistency of implementations against requirement models directly to overcome these limitations. Our approach extracts two behavioral models represented by Labelled Transition Systems（LTS） from requirement models and implementations respectively, and checks the behavioral consistency between these two models based on behavioral simulation relation of LTS. The checking results of our approach provide evidence for behavioral inconsistency as well as inconsistent localization. A research prototype called BCCH and a case study are presented to give initial validation of this approach.展开更多
We experimentally demonstrate a Faraday laser at Rb 1529 nm transition by using a performance-improved Rb electrodeless-discharge-lamp-based excited-state Faraday anomalous dispersion optical filter as the frequency- ...We experimentally demonstrate a Faraday laser at Rb 1529 nm transition by using a performance-improved Rb electrodeless-discharge-lamp-based excited-state Faraday anomalous dispersion optical filter as the frequency- selective element. Neither the electrical locking scheme nor the additional frequency-stabilized pump laser are used. The frequency of the external-cavity diode laser is stabilized to the Rb 1529 nm transition, and the Allan deviation of the Faraday laser is measured by converting the optical intensity into frequency. The Faraday laser can be used as a frequency standard in the telecom C band for further research on metrology, microwave photonics, and optical communication systems.展开更多
Agrifood systems in China and Africa are subject to increasing pressures due to resource limitations,environmental degradation and climate change.Both regions confront challenges such as soil degradation,water scarcit...Agrifood systems in China and Africa are subject to increasing pressures due to resource limitations,environmental degradation and climate change.Both regions confront challenges such as soil degradation,water scarcity and biodiversity loss,while also experiencing the adverse impacts of climate change on agricultural productivity and food security.This paper examines these challenges and outlines strategic actions with a systems approach being taken in both regions to transform their agrifood systems.Key strategies include enhancing agricultural efficiency,strengthening resilience to climate-related shocks,and promoting sustainability through innovative practices.Also,the paper emphasizes the importance of China-Africa cooperation in climate-smart production,trade and market optimization,and sustainable diets.The role of China-Africa food policy network in supporting these efforts are also discussed.The paper concludes with a call for continued collaboration to facilitate the sustainable transformation of agrifood systems in developing countries,particularly in China and Africa,ensuring food security and resilience for the future.展开更多
One critical aspect of bus service quality that influences riders’attitudes is the availability of seating and/or space to board vehicles.Unfortunately,little attention has been given to short-term passenger occupanc...One critical aspect of bus service quality that influences riders’attitudes is the availability of seating and/or space to board vehicles.Unfortunately,little attention has been given to short-term passenger occupancy predictions on individual buses.This research examines the use of conventional linear regression models and a machine-learning(random forest)model to predict passenger occupancies on individual buses when they arrive at future stops using data available in real-time from bus operations(e.g.,Automatic Passenger Counter(APC)systems)and weather information.Overall,the linear model(LM)and the random forest(RF)model are found to provide close estimates.Three sets of models are developed in this work to model the current and future stop pairs:a next-stop-based model that only models the occupancy at the right next stop and two models that predict the occupancy at any future stop along the bus route(called OD-pair based models).The OD-pair based models are found to predict passenger occupancies more accurately at downstream stops,regardless of whether the LM or RF is used.Examination of the transferability reveals that models can provide reliable estimates of future data when trained with historical information if demand patterns are fairly stable.These models and insights can be used by transit agencies in improving the quality and breadth of information provided to transit system users and even be integrated directly into real-time end-user feeds.展开更多
基金The Key Technology R& D Program of Jiangsu Scienceand Technology Department(No.BE2006010)the Key Technology R& DProgram of Nanjing Science and Technology Bureau(No.200601001)Sci-ence and Technology Research Projects of Nanjing Metro Headquarters(No.8550143007).
文摘The fund budget of multipurpose transit smart card systems is studied by stochastic programming to assign limited funds to different applications reasonably. Under the constraints of a gross fund, models of chance-constrained and dependentchance for the fund budget of multipurpose transit smart card systems are established with application scale and social demand as random variables, respectively aiming to maximize earnings and satisfy the service requirements the furthest; and the genetic algorithm based on stochastic simulation is adopted for model solution. The calculation results show that the fund budget differs greatly with different system objectives which can cause the systems to have distinct expansibilities, and the application scales of some applications may not satisfy user demands with limited funds. The analysis results indicate that the forecast of application scales and application future demands should be done first, and then the system objective is determined according to the system mission, which can help reduce the risks of fund budgets.
基金Project(BE2010043) supported by the Technology Support Program of Jiangsu Province,ChinaProject(CXZZ13_0928) supported by the Graduate Education Innovation Project of Jiangsu Province,China
文摘The novel method to analyze metallic structure corrosion status was proposed in the presence of stray current in DC mass transit systems. Firstly, the characteristic parameter and the influence parameters for the corrosion status were determined. Secondly, an experimental system was established for simulating the corrosion process within the stray current interference. Then, a predictive model for the corrosion status was built, using a support vector machine(SVM) method and experimental data. The data were divided into two sets, including training set and testing set. The training set was used to generate the SVM model and the testing set was used to evaluate the predictive performance of the SVM model. The results show that the relationship between the characteristic parameter and the influence parameters is nonlinear and the SVM model is suitable for predicting the corrosion status.
基金supported by the National Natural Science Foundation of China(1137100311461006)+4 种基金the Natural Science Foundation of Guangxi(2011GXNSFA0181542012GXNSFGA060003)the Science and Technology Foundation of Guangxi(10169-1)the Scientific Research Project from Guangxi Education Department(201012MS274)Open Research Fund Program of Guangxi Key Laboratory of Hybrid Computation and IC Design Analysis(HCIC201301)
文摘Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when interacting with the physical world, hence exact equivalence is restrictive and not robust. Using Baire met- ric, a generalized framework of transition system approximation is proposed by developing the notions of approximate language equivalence and approximate singleton failures （SF） equivalence. The framework takes the traditional exact equivalence as a special case. The approximate language equivalence is coarser than the approximate Slc equivalence, just like the hierarchy of the exact ones. The main conclusion is that the two approximate equiva- lences satisfy the transitive property, consequently, they can be successively used in transition system approximation.
文摘Strategic emerging industries represent the forefront of the new technological revolution and industrial transformation,serving as a critical domain for China to cultivate new growth drivers and establish competitive advantages.The development of these industries has become a major strategy for leading countries to attain competitive advantages in the new wave of economic and technological advancement.The ongoing energy revolution is driving the transition of traditional energy systems toward green and low-carbon models,while simultaneously fostering emerging industrial clusters such as new energy equipment manufacturing,energy storage,and energy internet.Energy companies are accelerating the deployment of innovative models that integrate new and traditional energy systems through technological and business model innovation.This study systematically analyzes the current status,trends,opportunities,and challenges faced by energy companies venturing into strategic emerging industries.The findings aim to guide energy companies in navigating the dual imperatives of energy transition and industrial upgrading,thereby contributing to sustainable development and global competitiveness.
基金supported by the NNSF of China(11071084,11026095 and 11201157)FDYT of Guangdong Province(2012LYM 0133)
文摘Let （X, f ） be a topological dynamical system, where X is a nonempty compact and metrizable space with the metric d and f ：X →X is a continuous map. For any integer n≥2, denote the product space by X（n）=X · · · × X｜ {z }n times . We say a system （X, f ） is generally distributionally n-chaotic if there exists a residual set D ？X（n） such that for any point x=（x1, · · · , xn）∈D, lim inf k→∞#（{i：0≤i≤k-1, min{d（fi（xj）, fi（xl））：1≤j 6=l≤n}〈δ0}） k=0 for some real numberδ0〉0 and lim sup k→∞#（{i：0≤i≤k-1, max{d（fi（xj）, fi（xl））：1≤j 6=l≤n}〈δ}） k=1 for any real number δ 〉 0, where #（·） means the cardinality of a set. In this paper, we show that for each integer n ≥ 2, there exists a system （X,σ） which satisfies the following conditions： （1） （X,σ） is transitive;（2） （X,σ） is generally distributionally n-chaotic, but has no distributionally （n＋1）-tuples;（3） the topological entropy of （X,σ） is zero and it has an IT-tuple.
基金Key Project of National Natural Science Foundation of China, No.41230632, No.71433008 Doctoral Project of Tianjin Normal University, No.52XB 1621Acknowledgments We thank Prof. Michael J. White in Brown University for the comments and suggestions on this research. We also thank the Writing Center in Brown University, Joan and John Kenower for the language revision.
文摘The floating population has become the main driver of urban population excessive growth in China＇s mega cities. Urban transit system （UTS） is a significant factor in population spatial distributions within urban areas, especially rapid and high-capacity transit systems. This paper analyzes the causal effects of the extension of expressways and subways between 2000 and 2010 in the Beijing Metropolitan Area （BMA）, focusing on the group differences between the local residents and the floating population. Due to the endogeneity of transportation improvements and population growth, Instrumental Variable （IV） regression model is applied to avoid this problem. The results show the local residents increased in the inner suburbs but decreased in the city center, while the floating population increased in the majority areas. IV regression results show that the extension of urban transit systems had statistically significant impacts on population growth across the BMA, The results also show that the extension of urban subway system had more effects on the floating population than the local residents across the BMA. It is mainly caused by the rather low fare of urban subway system. This implies that the excessive subsidy on urban subway system could result in ex- cessive floating population growth and residential differentiation, even residential segregation Hence, it is necessary to plan and design reasonable and scientific urban transit systems in order to advance reasonable population size and promote residential integration. Moreover, the regional analysis shows that the effects of urban transportation improvements on the local residents are not statistically significant in the inner suburbs. It implies that urban transportation improvements had limited effects on inducing people to move to suburban areas and controlling center city＇s population in Beijing. Therefore, it should be stressed the differenti- ated effects of urban transportation improvements on population distribution in the process of urban planning and population control.
基金Supported by the National Natural Science Foundation of China(91118003,61003071)the Fundamental Research Funds for the Central Universities(3101046,201121102020006)the Special Funds for Shenzhen Strategic New Industry Development(JCYJ20120616135936123)
文摘Checking if the implementations conform to the requirement models is challenging. Most existing techniques for consistency checking either focus on requirement models（e.g., requirements consistency checking）, or on the implementations（e.g., code-based testing） only. In this paper we propose an approach to checking behavioral consistency of implementations against requirement models directly to overcome these limitations. Our approach extracts two behavioral models represented by Labelled Transition Systems（LTS） from requirement models and implementations respectively, and checks the behavioral consistency between these two models based on behavioral simulation relation of LTS. The checking results of our approach provide evidence for behavioral inconsistency as well as inconsistent localization. A research prototype called BCCH and a case study are presented to give initial validation of this approach.
基金supported by the National Natural Science Foundation of China under Grant No.91436210
文摘We experimentally demonstrate a Faraday laser at Rb 1529 nm transition by using a performance-improved Rb electrodeless-discharge-lamp-based excited-state Faraday anomalous dispersion optical filter as the frequency- selective element. Neither the electrical locking scheme nor the additional frequency-stabilized pump laser are used. The frequency of the external-cavity diode laser is stabilized to the Rb 1529 nm transition, and the Allan deviation of the Faraday laser is measured by converting the optical intensity into frequency. The Faraday laser can be used as a frequency standard in the telecom C band for further research on metrology, microwave photonics, and optical communication systems.
基金funded by the National Natural Science Foundation of China(42201285,72061147002 and 72103188)the Young Scholars Program of the Chinese Academy of Social Sciences(2025QQJH60)funded by Research Projects on China-Africa Cooperation of the Chinese Academy of Social Sciences(CAI-J2024-02).
文摘Agrifood systems in China and Africa are subject to increasing pressures due to resource limitations,environmental degradation and climate change.Both regions confront challenges such as soil degradation,water scarcity and biodiversity loss,while also experiencing the adverse impacts of climate change on agricultural productivity and food security.This paper examines these challenges and outlines strategic actions with a systems approach being taken in both regions to transform their agrifood systems.Key strategies include enhancing agricultural efficiency,strengthening resilience to climate-related shocks,and promoting sustainability through innovative practices.Also,the paper emphasizes the importance of China-Africa cooperation in climate-smart production,trade and market optimization,and sustainable diets.The role of China-Africa food policy network in supporting these efforts are also discussed.The paper concludes with a call for continued collaboration to facilitate the sustainable transformation of agrifood systems in developing countries,particularly in China and Africa,ensuring food security and resilience for the future.
文摘One critical aspect of bus service quality that influences riders’attitudes is the availability of seating and/or space to board vehicles.Unfortunately,little attention has been given to short-term passenger occupancy predictions on individual buses.This research examines the use of conventional linear regression models and a machine-learning(random forest)model to predict passenger occupancies on individual buses when they arrive at future stops using data available in real-time from bus operations(e.g.,Automatic Passenger Counter(APC)systems)and weather information.Overall,the linear model(LM)and the random forest(RF)model are found to provide close estimates.Three sets of models are developed in this work to model the current and future stop pairs:a next-stop-based model that only models the occupancy at the right next stop and two models that predict the occupancy at any future stop along the bus route(called OD-pair based models).The OD-pair based models are found to predict passenger occupancies more accurately at downstream stops,regardless of whether the LM or RF is used.Examination of the transferability reveals that models can provide reliable estimates of future data when trained with historical information if demand patterns are fairly stable.These models and insights can be used by transit agencies in improving the quality and breadth of information provided to transit system users and even be integrated directly into real-time end-user feeds.
