Differential Evolution for Urban Transit Routing Problem

The urban transit routing problem (UTRP) involves the construction of route sets on existing road networks to cater for the transit demand efficiently. This is an NP-hard problem, where the generation of candidate route sets can lead to a number of potential routes being discarded on the grounds of infeasibility. This paper presents a new repair mechanism to complement the existing terminal repair and the make-small-change operators in dealing with the infeasibility of the candidate route set. When solving the UTRP, the general aim is to determine a set of transit route networks that achieves a minimum total cost for both the passenger and the operator. With this in mind, we propose a differential evolution (DE) algorithm for solving the UTRP with a specific objective of minimizing the average travel time of all served passengers. Computational experiments are performed on the basis of benchmark Mandl’s Swiss network. Computational results from the proposed repair mechanism are comparable with the existing repair mechanisms. Furthermore, the combined repair mechanisms of all three operators produced very promising results. In addition, the proposed DE algorithm outperformed most of the published results in the literature.

NEW RURAL SPACES: THE IMPACT OF RURAL INDUSTRIALIZATION ON RURAL-URBAN TRANSITION IN CHINA

Since the 1980s, rural-urban transition has been becoming one of the most important aspects in China’s fast transformation from traditional to modern modes. From the perspective of change of rural space, this paper examines the impact of rural industrialization on the rural-urban transition. After an introduction to the issue of rural-urban transition in rural-urban continuum, a historical overview of the transformations of China’s rural space in economic, social and geographical structure is presented. This is followed by an analysis of regiotal uneven development among provinces in rural industrialization and rural-urban transition. It is concluded that the fast industrialization of rural area has brought on many radical transformations of rural space in China, especially on the formation of new rural economic, social and geographical spaces and the uneven development of rural-urban trgnsition among the eastern, central and westem areas.

Parallel Multiple Tabu Search for Multiobjective Urban Transit Scheduling Problem

Urban Transit Scheduling Problem (UTSP) is concerned with determining reliable transit schedules for buses and drivers by considering the preferences of both passengers and operators based on the demand and the set of transit routes. This paper considered a UTSP which consisted of frequency setting, timetabling, and simultaneous bus and driver scheduling. A mixed integer multiobjective model was constructed to optimize the frequency of the routes by minimizing the number of buses, passenger’s waiting times and overcrowding. The model was further extended by incorporating timeslots in determining the frequencies during peak and off-peak hours throughout the time period. The timetabling problem studied two different scenarios which reflected the preferences of passengers and operators to assign the bus departure times at the first and last stop of a route. A set covering model was then adopted to minimize the number of buses and drivers simultaneously. A parallel tabu search algorithm was proposed to solve the problem by modifying the initialization process and incorporating intensification and diversification approaches to guide the search effectively from the different feasible domain in finding optimal solutions with lesser computational effort. Computational experiments were conducted on the well-known Mandl’s and Mumford’s benchmark networks to assess the effectiveness of the proposed algorithm. Competitive results are reported based on the performance metrics, as compared to other algorithms from the literature.

Greenhouse gas emission analysis and measurement for urban rail transit: A review of research progress and prospects

Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.

Function Analysis of Urban Rail Transit Smart Station

In order to make rail transit smart stations serve passengers better,the potential of smart stations should be optimized to reduce time cost,and relieve traffic congestion.In this paper,the construction of smart stations based on the management experience of a subway station and the benefits of smart stations were analyzed and discussed.The construction of smart stations,as well as the key technologies for the construction of smart stations,will aid in the automation and intelligent management of subway stations.

Exploring the differential impacts of urban transit system on the spatial distribution of local and floating population in Beijing

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.

Future 5G-Oriented System for Urban Rail Transit:Opportunities and Challenges

As a development direction of urban rail transit system,the train autonomous circumambulate system(TACS)can operate in a safer,more efficient,and more economical mode.However,most urban rail transit systems transmit signals through industrial,scientific,and medical(ISM)frequency bands or narrow frequency bands,which cannot meet the requirements of TACS.As a promising solution,the 5th generation(5G)mobile communication provides more services for the future urban rail transit systems,and covers the shortages of exiting communication technologies in terms of capacity and reliability.In this paper,we first briefly review the research status of current train control system and introduce its limitations.Next,we propose a novel network architecture,and present new technologies and requirements of the proposed architecture for TACS.Some potential challenges are then discussed to give insights for further research of TACS.

Optimization of train plan for urban rail transit in the multi-routing mode

The train plan of urban rail transit under multi-routing mode can be divided into three parts： train formation, train operation periods and corresponding train counts of each routing in each period. Based on the analysis of passen- ger＇s general travel expenses and operator＇s benefits, the constraints and objective functions are defined and the multiobjective optimization model for the train plan of urban rail transit is presented. Factors considered in the multi- objective optimization model include transport capacity, the requirements of traffic organization, corporation benefits, passenger demands, and passenger choice behavior under multi-train-routing mode. According to the characteristics of this model and practical planning experience, a three-phase solution was designed to gradually optimize the train formarion, train counts as well as operation periods. The instance of Changsha Metro Line 2 validates the feasibility and efficiency of this approach.

Industrial frequency single-phase AC traction power supply system for urban rail transit and its key technologies

To avoid stray current and maintain the benefit of no phase-split in the DC traction power supply system, an AC traction power supply system was proposed for the urban public transport such as metro and light rail transit. The proposed system consists of a main substation （MSS） and cable traction network （CTN）. The MSS includes a single-phase main traction transformer and a negative-se- quence compensation device, while the CTN includes double-core cables, traction transformers, overhead catenary system, rails, etc. Several key techniques for the proposed system were put forward and discussed, which can be summarized as （1） the power supply principle, equivalent circuit and transmission ability of the CTN, the cable-catenary matching technique, and the selection of catenary voltage level; （2） the segmentation technology and status identification method for traction power supply network, distributed and centralized protection schemes, etc.; （3） a power supply scheme for single-line MSS and a power supply scheme of MSS shared by two or more lines. The proposed industrial frequency single-phase AC traction power supply system shows an excellent technical performance, good economy, and high reliability, hence provides a new alternative for metro and urban rail transit power supply systems.

Landscape Design of Urban Rail Transit Complex Based on the Concept of Sustainable Development

On the basis of current development of urban rail transit complex in China,this paper proposed that it is necessary to build a complete landscape design system of urban traffic complex.Combined with the concept of sustainable urban landscape design,this paper explored landscape design of urban rail transit complex from the macroscopic,mesocopic and microscopic perspective,and analyzed many design cases to provide references for the sustainable landscape design of urban rail transit complex in China.

Importance Analysis of Urban Rail Transit Network Station Based on Passenger

Current urban rail transit has become a major mode of transportation, and passenger is an important factor of urban rail transport, so this article is based on passenger and the degree of the road network structure, calculating the point intensity of stations of urban rail transit, and then reaching a station importance by integrating many point intensities in a survey cycle time, and getting the station importance of urban rail transit network through concrete examples.

Research on Obstacle Detection Method of Urban Rail Transit Based on Multisensor Technology

With the rapid development of urban rail transit,passenger traffic is increasing,and obstacle violations are more frequent,and the safety of train operation under high-density traffic conditions is becoming more and more thought provoking.In order to monitor the train operating environment in real time,this paper first adopts multisensing technology based on machine vision and lidar,which is used to collect video images and ranging data of the track area in real time,and then it performs image preprocessing and division of regions of interest on the collected video.Then,the obstacles in the region of interest are detected to obtain the geometric characteristics and position information of the obstacles.Finally,according to the danger degree of obstacles,determine the degree of impact on the train operation,and use the signal system automatic response ormanual response mode to transmit the detection results to the corresponding train,so as to control the train operation.Through simulation analysis and experimental verification,the detection accuracy and control performance of the detection method are confirmed,which provides safety guarantee for the train operation.

Design of Integrated Monitoring and Early Warning System of Urban Rail Transit Train Running State

The monitoring and warning of urban rail transit is the core of operation management, and the breadth and depth of the monitoring range directly affect the quality of urban rail transit operation. For the current domestic monitoring system, most of the critical equipments and technologies are introduced from abroad;it is diseconomy, and also causes hidden danger. Realizing the localization of monitoring and early warning system is imperative. Based on the analysis of the present situation of urban rail transit operation safety at home and abroad, the paper proposes to use integrated technology to design basic framework of monitoring and warning system of urban rail train, and puts forward the critical technologies to realize the system. Compared with the existing monitoring system, the integrated monitoring system has the characteristics of wide monitoring range, clear division of labor, centralized management, coordination and integration operation and intelligent management, and embodies the concept of people-oriented. It has scientific significance for future construction of domestic Integrated Monitoring and Early Warning System (IMEWS) of urban rail transit.

The Research of Urban Rail Transit Sectional Passenger Flow Prediction Method

This paper studies the short-term prediction methods of sectional passenger flow, and selects BP neural network combined with the characteristics of sectional passenger flow itself. With a case study, we design three different schemes. We use Matlab to realize the prediction of the sectional passenger flow of the Beijing subway Line 2 and make comparative analysis. The empirical research shows that combining data characteristics of sectional passenger flow with the BP neural network have good prediction accuracy.

Integrated Layout and Transfer of Urban Rail Transit Hubs

This paper is engaged in the research of urban rail transit hub integration and transfer.Firstly,this paper focuses on the space division,the aggregation form of hub subsystems,the spatial layout of hub subsystems,and the design of integrated functions to achieve an integrated layout.In addition,this study also conducted a selection of transfer classification and transfer station layout of urban rail transit hubs,with the aims to promote the improvement of the functions of urban rail transit hubs,the rationality of transfers,and to improve the service quality of the hub system which meet the demand of the public travel.

Modified stochastic user-equilibrium assignment algorithm for urban rail transit under network operation

Based on the framework of method of successive averages(MSA), a modified stochastic user-equilibrium assignment algorithm was proposed, which can be used to calculate the passenger flow distribution of urban rail transit(URT) under network operation. In order to describe the congestion's impact to passengers' route choices, a generalized cost function with in-vehicle congestion was set up. Building on the k-th shortest path algorithm, a method for generating choice set with time constraint was embedded, considering the characteristics of network operation. A simple but efficient route choice model, which was derived from travel surveys for URT passengers in China, was introduced to perform the stochastic network loading at each iteration in the algorithm. Initial tests on the URT network in Shanghai City show that the methodology, with rational calculation time, promises to compute more precisely the passenger flow distribution of URT under network operation, compared with those practical algorithms used in today's China.

Rational scale of urban rail transit network based on system dynamics

Urban rail transit(URT) has been playing an important role in urban sustainable development with its advantages of high speed,large capacity,high efficiency and low pollution.Estimating URT network scale is the key to ensure the scientificity and feasibility of its construction.The existing studies on rational scale of URT network have not dealt with the interaction of supply and demand.This paper describes the establishment of a system dynamics model of rational URT network scale determination,considering the interaction between URT construction and city social economic development as well as the dynamic equilibrium of capital supply and traffic demand,and the verification of the model validity by applying it to the case of Wuhan City's URT construction.

National Standards for Urban Rail Transit

In this paper, we suggest the creation of passenger service standards for urban rail transit. We put forward standards suited for China's actual conditions, aimed at meeting an international level of service based on customer-oriented principles.