Pub Date : 2021-01-01DOI: 10.11908/J.ISSN.0253-374X.21158
yicheng Lu, Y. Zou, Kai Cheng, Lai Zheng, Selpi Selpi, Ting Zhu
A two-stage method of traffic conflict analysis was proposed based on risk region. By using the inD dataset, traffic conflicts were recognized with the calculation of time to risk region(tTTR), and then the degree of traffic conflict risk was judged by risk region duration. Compared with the method based on time-to-collision(tTTC), the proposed method can not only identify rear-end conflicts and crossing conflicts more effectively, but also characterize the degree of traffic conflict risk at different times.
{"title":"Analytical Method of Traffic Conflict at Urban Road Intersections Based on Risk Region","authors":"yicheng Lu, Y. Zou, Kai Cheng, Lai Zheng, Selpi Selpi, Ting Zhu","doi":"10.11908/J.ISSN.0253-374X.21158","DOIUrl":"https://doi.org/10.11908/J.ISSN.0253-374X.21158","url":null,"abstract":"A two-stage method of traffic conflict analysis was proposed based on risk region. By using the inD dataset, traffic conflicts were recognized with the calculation of time to risk region(tTTR), and then the degree of traffic conflict risk was judged by risk region duration. Compared with the method based on time-to-collision(tTTC), the proposed method can not only identify rear-end conflicts and crossing conflicts more effectively, but also characterize the degree of traffic conflict risk at different times.","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"27 1","pages":"941-948"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78141652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.11908/j.issn.0253-374x.2019.07.009
Jingqiu Guo, S. Fang, X. Qu, Yibing Wang, Yangzexi Liu
This paper aims to explore the impacts of connected and automated vehicles (CAV) on traffic flow efficiency based on in-depth microscopic simulation studies using cooperative gaming method. First, the Gipps car-following models were integrated into an improved cellular automata model to mimic the regular vehicle's driving behavior. Then, cooperative gaming method integrated with enhanced Q-learning was employed as the modeling platform for CAV, to strengthen the capability of the simulation system in realistically reproducing CAV lane changing and car following behavior. Finally, a 2-lane freeway stretch was applied to our simulations, and with extensive simulation studies we obtained some promising results. The study results suggest that the impacts of CAV are quite positive. The inclusion of CAV considerably improves traffic flow, mean speed, and traffic capacity. Such understanding is essential for research concerning CAV as well as the CAV implication for future traffic management and control.
{"title":"Characteristics of Mixed Traffic Flow in Two-lane Scenario Based on Cooperative Gaming Method","authors":"Jingqiu Guo, S. Fang, X. Qu, Yibing Wang, Yangzexi Liu","doi":"10.11908/j.issn.0253-374x.2019.07.009","DOIUrl":"https://doi.org/10.11908/j.issn.0253-374x.2019.07.009","url":null,"abstract":"This paper aims to explore the impacts of connected and automated vehicles (CAV) on traffic flow efficiency based on in-depth microscopic simulation studies using cooperative gaming method. First, the Gipps car-following models were integrated into an improved cellular automata model to mimic the regular vehicle's driving behavior. Then, cooperative gaming method integrated with enhanced Q-learning was employed as the modeling platform for CAV, to strengthen the capability of the simulation system in realistically reproducing CAV lane changing and car following behavior. Finally, a 2-lane freeway stretch was applied to our simulations, and with extensive simulation studies we obtained some promising results. The study results suggest that the impacts of CAV are quite positive. The inclusion of CAV considerably improves traffic flow, mean speed, and traffic capacity. Such understanding is essential for research concerning CAV as well as the CAV implication for future traffic management and control.","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"31 1","pages":"976-983"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82181682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-24DOI: 10.1201/9781315643274-175
Zhen Yang, Haifeng Han, Ziyi Xiong, Donglin Lei
Current code of tunnel design lacks specific criterion for judging horizontal alignment at entrance and exit zone of highway tunnel.After 3-second freezing of steer wheel,the deviation of the track from the desired path is proposed to evaluate the consistency of horizontal alignment at tunnel entrance and exit,and the control threshold is 0.2 m.The design conditions are classified into three groups and studied in detail.Spiral curve parameter is found to be a significant design index to guarantee the consistency.Then the equations for derivation calculation in different cases are deduced,and the indexes of the horizontal alignment at the tunnel entrance and exit zone are proposed for more flexible design.Based on the research results,an analysis is made of the consistency of the horizontal alignment of a tunnel of Longquan-Qingyuan expressway,and improvement is proposed.
{"title":"The consistency of horizontal alignment at tunnel entrance and exit zone","authors":"Zhen Yang, Haifeng Han, Ziyi Xiong, Donglin Lei","doi":"10.1201/9781315643274-175","DOIUrl":"https://doi.org/10.1201/9781315643274-175","url":null,"abstract":"Current code of tunnel design lacks specific criterion for judging horizontal alignment at entrance and exit zone of highway tunnel.After 3-second freezing of steer wheel,the deviation of the track from the desired path is proposed to evaluate the consistency of horizontal alignment at tunnel entrance and exit,and the control threshold is 0.2 m.The design conditions are classified into three groups and studied in detail.Spiral curve parameter is found to be a significant design index to guarantee the consistency.Then the equations for derivation calculation in different cases are deduced,and the indexes of the horizontal alignment at the tunnel entrance and exit zone are proposed for more flexible design.Based on the research results,an analysis is made of the consistency of the horizontal alignment of a tunnel of Longquan-Qingyuan expressway,and improvement is proposed.","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"51 1","pages":"1679-1689"},"PeriodicalIF":0.0,"publicationDate":"2016-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84748366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.11908/j.issn.0253-374x.2015.10.005
M. Jiang, C. Fu, J. He, Fangyuan Zhu
{"title":"Distinct element method simulation of bonded-type methane hydrate bearing sediments exploitation by thermal recovery-depressurization combined method","authors":"M. Jiang, C. Fu, J. He, Fangyuan Zhu","doi":"10.11908/j.issn.0253-374x.2015.10.005","DOIUrl":"https://doi.org/10.11908/j.issn.0253-374x.2015.10.005","url":null,"abstract":"","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"47 1","pages":"1480-1486"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79050826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3969/J.ISSN.0253-374X.2014.06.008
Jian Sun, Jie Sun
Based on dual-loop detector data and accident data collected on Shanghai expressway, the Bayesian networks (BN) model was adopted for the modeling and analysis of real-time traffic flow parameters and accident risk on expressways. Gaussian mixture model and the expectation-maximization algorithm which could effectively deal with the missing data were also used in the parameters estimation of BN model. Then real-time traffic safety risk was evaluated, and accident warning could be carried out in advance. Different combinations of dual-loop detector data and time segments before accidents were used to develop the optimal accident risk estimation model by BN. The results show that the BN model adopting the nearest detector data upstream and downstream of the accident site within 5 to 10 minutes before the accident performs the best and the accident prediction accuracy is up to 76.94%. At last, a comparative study was made of the classical accident risk estimation algorithms including naive Bayes classifier, K nearest neighbor and back propagation (BP) neural network as well as the existing real-time risk assessment studies. And the results show that the BN model obtains the best predictive results. Language: zh
{"title":"Proactive assessment of real-time traffic flow accident risk on urban expressway","authors":"Jian Sun, Jie Sun","doi":"10.3969/J.ISSN.0253-374X.2014.06.008","DOIUrl":"https://doi.org/10.3969/J.ISSN.0253-374X.2014.06.008","url":null,"abstract":"Based on dual-loop detector data and accident data collected on Shanghai expressway, the Bayesian networks (BN) model was adopted for the modeling and analysis of real-time traffic flow parameters and accident risk on expressways. Gaussian mixture model and the expectation-maximization algorithm which could effectively deal with the missing data were also used in the parameters estimation of BN model. Then real-time traffic safety risk was evaluated, and accident warning could be carried out in advance. Different combinations of dual-loop detector data and time segments before accidents were used to develop the optimal accident risk estimation model by BN. The results show that the BN model adopting the nearest detector data upstream and downstream of the accident site within 5 to 10 minutes before the accident performs the best and the accident prediction accuracy is up to 76.94%. At last, a comparative study was made of the classical accident risk estimation algorithms including naive Bayes classifier, K nearest neighbor and back propagation (BP) neural network as well as the existing real-time risk assessment studies. And the results show that the BN model obtains the best predictive results. Language: zh","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"52 1","pages":"873-879"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85686806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.11908/J.ISSN.0253-374X.2015.02.009
F. Jia, Jie Sun, Jian Sun
Based on accident data and detector data collected on two expressways in Shanghai, important variables for model construction were selected from the data of traffic flow within 5~10 min before the accident with random forest model. Then, the Bayesian network (BN) model based on the Gaussian mixture model and expected maximum algorithm was established for the analysis of real-time traffic flow state and accident risk. Meanwhile, the transferability of BN model was also assessed. The results show that BN model built with selected important variables is better than that with direct detection data, with the accident prediction accuracy rate of 82.78%. The results of the transferability show that the improved BN model is still better than the traditional model, though the accident prediction accuracy of BN model decreases.
{"title":"Key variables identification and proactive assessment of real-time traffic flow accident risk on urban expressway","authors":"F. Jia, Jie Sun, Jian Sun","doi":"10.11908/J.ISSN.0253-374X.2015.02.009","DOIUrl":"https://doi.org/10.11908/J.ISSN.0253-374X.2015.02.009","url":null,"abstract":"Based on accident data and detector data collected on two expressways in Shanghai, important variables for model construction were selected from the data of traffic flow within 5~10 min before the accident with random forest model. Then, the Bayesian network (BN) model based on the Gaussian mixture model and expected maximum algorithm was established for the analysis of real-time traffic flow state and accident risk. Meanwhile, the transferability of BN model was also assessed. The results show that BN model built with selected important variables is better than that with direct detection data, with the accident prediction accuracy rate of 82.78%. The results of the transferability show that the improved BN model is still better than the traditional model, though the accident prediction accuracy of BN model decreases.","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88643450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.11908/J.ISSN.0253-374X.2014.12.004
Jianfeng Chen, Junxiu Liu, J. Xue
{"title":"Centrifugal test on a reinforced soil wall with flexible/rigid facings","authors":"Jianfeng Chen, Junxiu Liu, J. Xue","doi":"10.11908/J.ISSN.0253-374X.2014.12.004","DOIUrl":"https://doi.org/10.11908/J.ISSN.0253-374X.2014.12.004","url":null,"abstract":"","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"14 1","pages":"1805-1811"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80879357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.3969/J.ISSN.0253-374X.2013.01.024
Hui Xie, Yingchun Tan, Guoqin Tai, Ran Liu
"Folds" may appear when the depth-image-based rendering(DIBR) technique is used to generate destination image.In order to remove the folds,an approach to determine the scan order of reference image by view judgment is proposed.First,the z coordinate of epipole is set as an infinitesimal,then the scan order of reference image rendering the left or the right view is determined by the new homogeneous coordinates of epipole.Accordingly,the scan order of reference image can be determined by the destination image which is left view or right view.Experimental results show that the proposed approach can eliminate folds with less complexity in contrast to the Z-buffer algorithm,and it is adaptable to virtual view rendering when the virtual viewpoint shifts horizontally.
{"title":"A DIBR View Judgment-based Fold-elimination Approach","authors":"Hui Xie, Yingchun Tan, Guoqin Tai, Ran Liu","doi":"10.3969/J.ISSN.0253-374X.2013.01.024","DOIUrl":"https://doi.org/10.3969/J.ISSN.0253-374X.2013.01.024","url":null,"abstract":"\"Folds\" may appear when the depth-image-based rendering(DIBR) technique is used to generate destination image.In order to remove the folds,an approach to determine the scan order of reference image by view judgment is proposed.First,the z coordinate of epipole is set as an infinitesimal,then the scan order of reference image rendering the left or the right view is determined by the new homogeneous coordinates of epipole.Accordingly,the scan order of reference image can be determined by the destination image which is left view or right view.Experimental results show that the proposed approach can eliminate folds with less complexity in contrast to the Z-buffer algorithm,and it is adaptable to virtual view rendering when the virtual viewpoint shifts horizontally.","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75707683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of temperature and stirring on biogas production by anaerobic fermentation with bagasse","authors":"Xinliang Gao, Shuiping Yan, Qingyao He, Chaoyang Fang","doi":"10.3969/J.ISSN.0253-374X.2012.S2.009","DOIUrl":"https://doi.org/10.3969/J.ISSN.0253-374X.2012.S2.009","url":null,"abstract":"","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"26 Pt 5 1","pages":"40-46"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78436122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance of CO2 absorption from biogas by using novel amino acid salts","authors":"Shuiping Yan, Jing'ao Chen, Qingyao He, Ping Ai, Wang Yuanyuan, Yan-lin Zhang","doi":"10.3969/J.ISSN.0253-374X.2012.S2.026","DOIUrl":"https://doi.org/10.3969/J.ISSN.0253-374X.2012.S2.026","url":null,"abstract":"","PeriodicalId":17444,"journal":{"name":"Journal of Tongji University","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76554353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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