To realize a better automatic train driving operation control strategy for urban rail trains,an automatic train driving method with improved DQN algorithm(classical deep reinforcement learning algorithm)is proposed as...To realize a better automatic train driving operation control strategy for urban rail trains,an automatic train driving method with improved DQN algorithm(classical deep reinforcement learning algorithm)is proposed as a research object.Firstly,the train control model is established by considering the train operation requirements.Secondly,the dueling network and DDQN ideas are introduced to prevent the value function overestimation problem.Finally,the priority experience playback and“restricted speed arrival time”are used to reduce the useless experience utilization.The experiments are carried out to verify the train operation strategy method by simulating the actual line conditions.From the experimental results,the train operation meets the ATO requirements,the energy consumption is 15.75%more energy-efficient than the actual operation,and the algorithm convergence speed is improved by about 37%.The improved DQN method not only enhances the efficiency of the algorithm but also forms a more effective operation strategy than the actual operation,thereby contributing meaningfully to the advancement of automatic train operation intelligence.展开更多
Square confined concrete arch is increasingly used in deep soft rock roadway support because of its advantages of high strength and construction convenience.However,the design of confined concrete arch in underground ...Square confined concrete arch is increasingly used in deep soft rock roadway support because of its advantages of high strength and construction convenience.However,the design of confined concrete arch in underground engineering still remains in experience-based method and lacks quantitative analysis.As a connecting component between arch sections,the connection joints have an important influence on the internal force distribution and failure mechanism of support arch.Therefore,a reasonable design of arch joints is the premise of rational support design.Taking Liangjia Coal Mine,a typical deep soft rock mine in China,as research background,this paper fully compared the most widely used joint types of confined concrete arch as analytical objects:flange joints and casing joints.The main failure modes of these two kinds of joints under bending moment are defined.Laboratory and numerical tests are carried out to study the mechanical characteristics of joints.Based on the M-θ curve,the influence law of different design parameters is analyzed,and the design principles of joints are proposed.The research results could provide a theoretical basis for the design and application of confined concrete arch in related projects.展开更多
Rather than maintaining the classic teaching approach, a growing number of schools use the blended learning system in higher education. The traditional method of teaching focuses on the result of students' progres...Rather than maintaining the classic teaching approach, a growing number of schools use the blended learning system in higher education. The traditional method of teaching focuses on the result of students' progress. However, many student activities are recorded by an online programming learning platform at present. In this paper, we focus on student behavior when completing an online open-ended programming task. First, we conduct statistical analysis to examine student behavior on the basis of test times and completed time. By combining these two factors, we then classify student behavior into four types by using k-means algorithm. The results are useful for teachers to enhance their understanding of student learning and for students to know their learning style in depth. The findings are also valuable to re-design the learning platform.展开更多
In the field of Chinese higher education,gender is still a significant issue,as is a general ignorance of gender discrimination against women.Issues related to gender can be observed throughout the process of educatio...In the field of Chinese higher education,gender is still a significant issue,as is a general ignorance of gender discrimination against women.Issues related to gender can be observed throughout the process of education:at the time of entering an institution,during the educational process and as an outcome of education.The following seven aspects of sexual discrimination occur in Chinese higher education system:(1)Fewer opportunities for women in higher education than for men;(2)within disciplines and specializations there exists the phenomena of gender segregation and diffluence;(3)considerable gender difference exists in the distribution of school resources;(4)teaching materials and teaching content are gender discriminatory;(5)within higher education institutions,student organizations have a degree of gender imbalance;(6)campus culture has a hidden agenda of gender discrimination;and(7)employment prospects for women tend to be unequal and discriminatory.展开更多
文摘To realize a better automatic train driving operation control strategy for urban rail trains,an automatic train driving method with improved DQN algorithm(classical deep reinforcement learning algorithm)is proposed as a research object.Firstly,the train control model is established by considering the train operation requirements.Secondly,the dueling network and DDQN ideas are introduced to prevent the value function overestimation problem.Finally,the priority experience playback and“restricted speed arrival time”are used to reduce the useless experience utilization.The experiments are carried out to verify the train operation strategy method by simulating the actual line conditions.From the experimental results,the train operation meets the ATO requirements,the energy consumption is 15.75%more energy-efficient than the actual operation,and the algorithm convergence speed is improved by about 37%.The improved DQN method not only enhances the efficiency of the algorithm but also forms a more effective operation strategy than the actual operation,thereby contributing meaningfully to the advancement of automatic train operation intelligence.
基金This study was funded by The Natural Science Foundation of Shandong Province,China(Nos.ZR2017QEE013,2017GGX30101,2018GGX109001)The Young Scholars Program of Shandong University(2018WLJH76)The Research Fund of The State Key Laboratory of Coal Resources and safe Mining,CUMT(SKLCRSM18KF012).
文摘Square confined concrete arch is increasingly used in deep soft rock roadway support because of its advantages of high strength and construction convenience.However,the design of confined concrete arch in underground engineering still remains in experience-based method and lacks quantitative analysis.As a connecting component between arch sections,the connection joints have an important influence on the internal force distribution and failure mechanism of support arch.Therefore,a reasonable design of arch joints is the premise of rational support design.Taking Liangjia Coal Mine,a typical deep soft rock mine in China,as research background,this paper fully compared the most widely used joint types of confined concrete arch as analytical objects:flange joints and casing joints.The main failure modes of these two kinds of joints under bending moment are defined.Laboratory and numerical tests are carried out to study the mechanical characteristics of joints.Based on the M-θ curve,the influence law of different design parameters is analyzed,and the design principles of joints are proposed.The research results could provide a theoretical basis for the design and application of confined concrete arch in related projects.
基金supported by the National Grand R&D Plan (Grant No.2016YFB1000805)National Natural Science Foundation of China (Grant No.61702534,61432020,61472430,61502512)
文摘Rather than maintaining the classic teaching approach, a growing number of schools use the blended learning system in higher education. The traditional method of teaching focuses on the result of students' progress. However, many student activities are recorded by an online programming learning platform at present. In this paper, we focus on student behavior when completing an online open-ended programming task. First, we conduct statistical analysis to examine student behavior on the basis of test times and completed time. By combining these two factors, we then classify student behavior into four types by using k-means algorithm. The results are useful for teachers to enhance their understanding of student learning and for students to know their learning style in depth. The findings are also valuable to re-design the learning platform.
文摘In the field of Chinese higher education,gender is still a significant issue,as is a general ignorance of gender discrimination against women.Issues related to gender can be observed throughout the process of education:at the time of entering an institution,during the educational process and as an outcome of education.The following seven aspects of sexual discrimination occur in Chinese higher education system:(1)Fewer opportunities for women in higher education than for men;(2)within disciplines and specializations there exists the phenomena of gender segregation and diffluence;(3)considerable gender difference exists in the distribution of school resources;(4)teaching materials and teaching content are gender discriminatory;(5)within higher education institutions,student organizations have a degree of gender imbalance;(6)campus culture has a hidden agenda of gender discrimination;and(7)employment prospects for women tend to be unequal and discriminatory.
