Dong Honghui

Virtual speed sensors based algorithm for expressway traffic state estimation

The accurate estimation of expressway traffic state can provide decision-making for both travelers and traffic managers. The speed is one of the most representative parameter of the traffic state. So the expressway speed spatial distribution can be taken as the expressway traffic state equivalent. In this paper, an algorithm based on virtual speed sensors (VSS) is presented to estimate the expressway traffic state (the speed spatial distribution). To gain the spatial distribution of expressway traffic state, virtual speed sensors are defined between adjacent traffic flow sensors. Then, the speed data extracted from traffic flow sensors in time series are mapped to space series to design virtual speed sensors. Then the speed of virtual speed sensors can be calculated with the weight matrix which is related with the speed of virtual speed sensors and the speed data extracted from traffic flow sensors and the speed data extracted from traffic flow sensors in time series. Finally, the expressway traffic state (the speed spatial distribution) can be gained. The acquisition of average travel speed of the expressway is taken for application of this traffic state estimation algorithm. One typical expressway in Beijing is adopted for the experiment analysis. The results prove that this traffic state estimation approach based on VSS is feasible and can achieve a high accuracy.

Access Point Research in Rail Train Safety Monitoring Sensor Network

Rail train safety monitoring sensor network is an important screen of guaranteeing the train safe, efficient, and reliable operation, the access point and fusion point are data transmission confluence center of the train safety monitoring sensor network, so reasonable configuration to the access point and fusion point has great significance to ensure the train safety operation. In this paper, basis on the existing city rail train safety monitoring network research results, analyzed and researched the function structure and performance index of access point.

Regional traffic state estimation with a GPS-based method

Through vehicle-mounted GPS date and map-matching technique, vehicle GPS locating point was matched within the corresponding traffic region by using circle split method, and the issue of acquisition of region traffic state was resolved. In this paper, technique process of acquisition of region traffic state based on map matching was sketched firstly, then region matching method was deeply researched, circle split method was put forward to perform region matching, and speed distribution curve was obtained by calculation, thus feasibility of circle split method was verified.

Research on the passenger comfort evaluation system of urban rail transit

The development of economy brings changes to peoples lifestyle. The growing requirements for service quality puts forward new challenges to the operation and development of urban rail transit. Therefore, the research of train comfort degree has positive significance. The paper analyzes the main influencing factors of train comfort degree based on scientific methods of system evaluation, and a suitable evaluation method for each evaluation index of the system is determined. Then we use subjective survey, analytic hierarchy process (AHP) and correlation matrix evaluation method to determine the weight coefficient of each evaluation index. Finally, we present the mathematical model of the whole evaluation system using the centesimal system, realizing the overall evaluation of the train comfort degree.

A bandwidth allocation strategy for train-to-ground communication networks

This paper formulates the bandwidth allocation problem in train-to-ground wireless communication networks in operational process of trains. It is shown that the Nash Bargaining game provides an Asymmetric Nash Bargaining Solution which is fair to bandwidth allocation problems in different services. We proposed a bandwidth allocation model for train-to-ground communication system. It can effectively reflect allocation strategies for services with different bargaining power. We define a dynamic adaptive function of bargaining power in order to match utility functions under diverse bandwidths. Easily to implement as it is, an algorithm for bandwidth allocation is derived and then simulated. The simulation show that the proposed scheme has high rate of resource utilization, and is suitable for train-to-ground communication systems.This paper formulates the bandwidth allocation problem in train-to-ground wireless communication networks in operational process of trains. It is shown that the Nash Bargaining game provides an Asymmetric Nash Bargaining Solution which is fair to bandwidth allocation problems in different services. We proposed a bandwidth allocation model for train-to-ground communication system. It can effectively reflect allocation strategies for services with different bargaining power. We define a dynamic adaptive function of bargaining power in order to match utility functions under diverse bandwidths. Easily to implement as it is, an algorithm for bandwidth allocation is derived and then simulated. The simulation show that the proposed scheme has high rate of resource utilization, and is suitable for train-to-ground communication systems.

A route-choice method based on zone traffic signal coordination control

Traditional green band was focused on straight lines. However, the origin and destination of the main traffic flow in the road network are usually diagonal. Apparently, a straight green band cannot meet the traffic demand in this case. Therefore, it is necessary to study green band with turnings in the zone traffic signal coordination control. This article focuses on the method which could compute the optimal route for an extra traffic flow of commuters and set the green band in a square area of 4*3 intersections, given the basic information of road conditions, traffic volume, split setting, etc. In the simulation, this article uses the data from Huilongguan area in Beijing. Using the Synchro to simulate the road network, it distributes the traffic flow of commuters into four routes respectively and gets the reports of network performance after simulation of each situation. The reports shows that the optimal route, which performs better in the measure of effectiveness, such as delay per vehicle, stops delay per vehicle, speed, fuel combustion efficiency, width of green band, bandwidth efficiency, is exactly consistent with the results calculated by Rout-Choice model.

Design and analysis of a real-time quality evaluation index for expressways

Expressways are the important component to the urban road network. The traffic operation quality evaluation report can provide the traffic managers and users decision supports to alleviate the traffic congestion. This paper designs a new traffic loading degree index and calculation method based on time occupancy to evaluate the real time traffic operation quality. Based on huge amounts of traffic data detected from Beijing Expressways, the reference thresholds of the new index are determined to represent different traffic statuses. The experiment analysis using the data from 2nd Ring Road in Beijing illuminates the method of effectivity and practicability.

Slow traffic language design - a case study of Xizhimen subway station of Beijing

Explain the need for rail slow traffic language design, outlining its design principles, and taking Beijing Xizhimen subway station as an example to launch on-the-spot investigation, summarizing the designing defections of the Xizhimen subway station slow traffic language design. Combination of domestic and international rail traffic slow language design principles, and recommendations on Chinas track slow traffic language system design.

Algorithm of VMS site optimization in network based on comprehensive route impedance

Variable Message Sign is an important equipment for route guidance. Its location influences the redistribution of traffic flow in traffic network. The comprehensive route impedance consisting of section travel time and intersection delay reveals the state of road effectively. Route impedance is calculated by real traffic data of section travel time and intersection delay. The optimal goal is to make the value of utility function maximum. On the basis of comparing the objective function value, the final scheme is the scheme with maximum value of utility function. The real network between Xizhimen interchange and Fuxingmen interchange was applied in an instance. Using the algorithm of VMS site optimization based on comprehensive impedance, the result of the instance fits well to real situation and the trend of VMS construction in this area.