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
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
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
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
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.
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.