Browsing by Author "Huang, Heng"

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A circuit simulation technique for congested network traffic assignment problem
(2007)
Cho, Hsun-Jung
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Huang, Heng
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
The relation between electrical circuit and traffic network has been proposed by Sasaki and Inouye, but they proposed link cost function is a linear function which cannot present the congestion situation. Cho and Huang extended the link cost function to a nonlinear function which can explain the congested network. In this paper, we proposed a foremost and novel approach to solve the traffic assignment problem (TAP) by simulating the electrical circuit network which consists of nonlinear link cost function models. Comparing with the solutions of Frank-Wolfe algorithm, the simulation results are nearly identical. Thus, the simulation of a network circuit model can be applied to solve network traffic assignment problems. Finally, two examples are proposed, and the results confirmed that electrical circuit simulation is workable in solving congested network traffic assignment problems.
A circuit simulation technique for network assignment problem
(2005)
Cho, Hsun-Jung
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Lee, Tsu-Tian
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Huang, Heng
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
In this paper, under the network user equilibrium principle (Wardrop, 1952), a method to use the analogous electric circuit to simulate network traffic assignment, and to measure the current flow and voltage of the electric circuit to present the result of traffic assignment is proposed. The basic ideas are using the resistance and constant voltage source combines the analogous electric circuit and using the current source presents the net traffic flow. Also, the nonlinear link cost function is approximated by the piecewise function. Finally, an example shows that an electric circuit simulating the network traffic assignment is workable.
Estimating Individual Vehicle Speed by FMCW Radar Detector
(2009)
Cho, Hsun-Jung
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Huang, Heng
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
For a side-looking frequency-modulated continuous wave (FMCW) radar detector, the information of vehicle speed can not be obtained by Doppler frequency directly. This is due to the detector is perpendicular to marching direction vehicle, therefore, Doppler shift of the beat signal is unapparent. Consequently, the length of detection zone, vehicle length, and the on-time duration of vehicle are three parameters in estimating individual vehicle speed by FMCW radar detectors. Among these parameters, vehicle length and detector on-time can be acquired by time-frequency signal analysis and statistical pattern recognition techniques. Therefore, how to determine the length of detection zone is the remaining problem. In this study, a method of estimating the length of detection zone based on antenna pattern and radar equation is proposed. According to the antenna pattern, the antenna gain is a function of angles in azimuth (phi), and elevation (theta) planes, such as G(phi, theta). For each point on the road surface, based on the radar equation, the relative received power can be calculated as long as the position and angle of the detector are given. After setting a threshold value of the relative received power, the length of detection zone on each lane can be determined. In field test, a side-looking 10.5 GHz FMCW radar is used to detect vehicles and the antenna pattern is given. The radar detector is installed at 6 meters height and the angle of depression is nearly 20 degrees. Based on the method described above and set the threshold value equal to 0.0015, then the length of detection zone on each lane can be obtained. According to the length of detection zone, vehicle length, and the on-time duration, the speed of each vehicle can be estimated. Moreover, the accuracy of lane 1 and lane 2 are 84.46% and 83.48% respectively.
Method for identification of traffic lane boundary
(2010-06-24)
Jou, Yow-Jen
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Cho, Hsun-Jung
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Chen, Yu-Kuang
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Huang, Heng
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Hsu, Chia-Chun
The invention provides a method for identification of traffic lane boundary. Firstly the microwave signal is received, and the noise reduction is treated for the microwave signal. Then the frequency domain information is employed to calculate the legal set of closed interval, in order to form the frequency span information. Finally, the probability density function model is employed to calculate the frequency span information in order to identify the traffic lane boundary.