As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by g...As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.展开更多
Population movement is an important phenomenon in China in recent years. Its mechanism is: (1) thrust of more people and less land in the eastern region of China; (2) attraction of dual economy in the western region o...Population movement is an important phenomenon in China in recent years. Its mechanism is: (1) thrust of more people and less land in the eastern region of China; (2) attraction of dual economy in the western region of China; (3) national policy on preferential wages and grains for the western region. Population movement has an important effect on the change of regional division pattern in China: by the medium of the moving people, there forms another regional division pattern, i.e. rural industry system based on rural town industry; (2) there forms another profit mechanism compensated from the western region to the eastern region. It not only wins more profit in the eastern region, but also changes dual economy in the western region. Therefore, We should make choice of a comprehensible and encouraging attitude on population movement; a special government organization for general survey of the moving people should be set up at once.展开更多
A three-dimensional semicircle cold model of COREX melter gasifier(MG)was established,and the effects of coke charging pattern on burden movement were investigated by adopting this model.The burden flow pattern of pac...A three-dimensional semicircle cold model of COREX melter gasifier(MG)was established,and the effects of coke charging pattern on burden movement were investigated by adopting this model.The burden flow pattern of packed bed was measured with different coke charging amounts,coke charging positions,and coke sizes.The results show that the solid flow pattern presents a change from straight line type to reverse U type and finally to W type in MG with traditional coke charging,while the burden flow pattern experiences the change from straight line type to W type with platform and finally W type under center coke charging,and the solid flow pattern presents a change from straight line type to W type with platform and finally W type under intermediate coke charging.The difference demonstrates that coke charging pattern affects the uniform descending in MG to some degree.The burden in the coke charging zone keeps a straight line descending.No matter what kind of coke charging pattern is adopted,the burden residence time is shortened with the increase in coke charging amount,and the vertex of deadman decreases obviously,which is conducive to the renewal of the deadman.The appropriate coke charging amount and coke size should be well controlled at 8.7%and 5 mm,respectively.The results are useful not only in developing further understanding of solid flow in MG but also in verifying different mathematical models,particularly the coupled discrete element method with computational fluid dynamics simulation which has been increasingly used in the literature.展开更多
Our previous study suggested that the subcutaneous muscle displacement caused by joint movements might alter muscle activation patterns and thus affect the classification performance.To further analyze the effect of j...Our previous study suggested that the subcutaneous muscle displacement caused by joint movements might alter muscle activation patterns and thus affect the classification performance.To further analyze the effect of joint movements on the online performance of Electromyography(EMG)Pattern Recognition(PR),this study assessed online classification performance with and without joint movements.EMG signals were recorded from the dominant forearm of 10 able-bodied subjects under two motion scenarios:Hand and Wrist Joints Unconstrained(HAWJU)and Constrained(HAWJC).Sixth-order autoregressive coefficients and four time-domain features were extracted from EMG signals.Linear Discriminant Analysis(LDA)models were trained to perform an online performance evaluation of the limb motions.The experimental results showed that the four online performance metrics:Motion Selection Time(MST),Motion Completion Time(MCT),Motion Completion Rate(MCR),and Online Classification Accuracy(ONCA)were 0.35 s,1.44 s,97.40%,and 82.61%for HAWJU and 0.37 s,1.47 s,89.70%,and 73.57%for HAWJC,respectively.The outcomes of this study indicated that subcutaneous muscle displacement due to joint movements has a positive effect on online classification performance.The absence of joint movements may be a physiological factor contributing to the poor online performance of the EMG-PR of transradial amputees.This study can provide a new perspective for improving the online performance of EMG-PR for transradial amputees.展开更多
Electromyography(EMG)pattern recognition has been widely employed for prosthesis control.Several studies demonstrated that amputees had poorer performances of EMG pattern recognition when compared to able-bodied indiv...Electromyography(EMG)pattern recognition has been widely employed for prosthesis control.Several studies demonstrated that amputees had poorer performances of EMG pattern recognition when compared to able-bodied individuals.Several factors,such as the muscle weakness and atrophy of residual limbs,the length of residual limbs,and the decrease of the affected side's motor cortex,had been studied to improve the performance of amputees.However,there was no study on the factor that the absence of joint movements for amputees.This study aimed to investigate whether the hand and wrist joint movements had effects on the EMG pattern recognition.Ten able-bodied subjects were tested for 11 hand and wrist gestures with two different gesture modalities:hand and wrist joints unconstrained(HAWJU)and constrained(HAWJC).Time-domain(TD)features and Linear Discriminant Analysis(LDA)were employed to compare the classification performance of the two modalities.Compared to HAWJU,HAWJC significantly reduced the average Classification Accuracy(CA)across all subjects from 95.53 to 85.52%.The experimental results demonstrated that the hand and wrist joint movements had significant effects on EMG pattern recognition.The outcomes provided a new perspective to study the factors affecting EMG pattern recognition.展开更多
This study focuses on addressing ventilation and dust removal challenges during the construction of small-section tunnels using drilling and blasting techniques.Specifically,the research examines the shale gas gatheri...This study focuses on addressing ventilation and dust removal challenges during the construction of small-section tunnels using drilling and blasting techniques.Specifically,the research examines the shale gas gathering and transmission trunk line project in the Weiyuan and Luzhou blocks.To gain deeper insights into dust migration patterns,numerical simulations were conducted.The study further analyzed dust migration behavior in small-section tunnels and large steep-sloped shafts,taking into account various factors such as ventilation distance,tunnel slope,and section size.The results indicate that optimal ventilation occurs at distances of 15 and 13 m.Additionally,dust concentration was notably lower when the tunnel slope was 0°,suggesting that a flat slope is more advantageous for construction projects where the outlet wind speed remains constant.Moreover,as the tunnel’s cross-sectional size increases,dust concentration decreases significantly,further underscoring the benefits of larger tunnel sections in mitigating dust accumulation.展开更多
In this paper,multi_quadric equations interpolation is used to establish a widely covered and valuable speed field model,with which the crustal movement image is obtained.
The objective of this work is to investigate the influence of smoke movement during mine fires on miner evacuation behaviors. A three-dimensional computational fluid dynamics method was conducted to reconstruct the la...The objective of this work is to investigate the influence of smoke movement during mine fires on miner evacuation behaviors. A three-dimensional computational fluid dynamics method was conducted to reconstruct the lane- way conveyor belt fire scenes under two ventilating conditions. The parameters, including temperature-time histories, soot density, carbon monoxide and heat release rate, were simulated to characterize the mine fires at various ventilating speeds. A miner evacuation model affected by fire smoke movement was advanced to describe the miner evacuation behaviors, which can be divided into three stages. Based on the evacuation model coupled with the mine fire smoke movement, the available safety evacuation time for miners involved in coal mine fire located in different sites was estimated. Two evacuation patterns were advanced according to the ventilating speeds combined with the model of miner evacuation behaviors. The results show that the miners located between the inlet-air end and the air door in lane 1 should be evacuated to the inlet-air end and other miners involved in coal mine fire could choose the air door as the escaping destination, when the ventilation speed is greater than 3 m/s. Accordingly, the research can be used as references for the mine safety administration authorities to design the safety evacuation.展开更多
The rhythmic movement is a spontaneous behavior due to the central pattern generator （CPG）. At present, the CPG model only shows the spontaneous behavior, but does not refer to the instruction regulation role of the...The rhythmic movement is a spontaneous behavior due to the central pattern generator （CPG）. At present, the CPG model only shows the spontaneous behavior, but does not refer to the instruction regulation role of the cerebral cortex. In this paper, a modified model based on the Matsuoka neural oscillator theory is presented to better show the regulation role of the cerebral cortex signal to the CPG neuronal network. The complex interaction between the input signal and other parameters in the CPG network is established, making all parameters of the CPG vary with the input signal. In this way, the effect of the input signal to the CPG network is enhanced so that the CPG network can express the self-regulation movement state instead of being limited to the spontaneous behavior, and thus the regulation role of the cerebral cortex signal can be reflected. Numerical simulation shows that the modified model can generate various movement forms with different modes, frequencies, and interchanges between them. It is revealed in theories that the cerebral cortex signal can regulate the mode and frequency of the gait in the ~ourse of the gait movement.展开更多
Articulated movements are fundamental in many human and robotic tasks.While humans can learn and generalise arbitrarily long sequences of movements,and particularly can optimise them to ft the constraints and features...Articulated movements are fundamental in many human and robotic tasks.While humans can learn and generalise arbitrarily long sequences of movements,and particularly can optimise them to ft the constraints and features of their body,robots are often programmed to execute point-to-point precise but fxed patterns.This study proposes a new approach to interpreting and reproducing articulated and complex trajectories as a set of known robot-based primitives.Instead of achieving accurate reproductions,the proposed approach aims at interpreting data in an agent-centred fashion,according to an agent s primitive movements.The method improves the accuracy of a reproduction with an incremental process that seeks frst a rough approximation by capturing the most essential features of a demonstrated trajectory.Observing the discrepancy between the demonstrated and reproduced trajectories,the process then proceeds with incremental decompositions and new searches in sub-optimal parts of the trajectory.The aim is to achieve an agent-centred interpretation and progressive learning that fts in the frst place the robots capability,as opposed to a data-centred decomposition analysis.Tests on both geometric and human generated trajectories reveal that the use of own primitives results in remarkable robustness and generalisation properties of the method.In particular,because trajectories are understood and abstracted by means of agent-optimised primitives,the method has two main features： 1） Reproduced trajectories are general and represent an abstraction of the data.2） The algorithm is capable of reconstructing highly noisy or corrupted data without pre-processing thanks to an implicit and emergent noise suppression and feature detection.This study suggests a novel bio-inspired approach to interpreting,learning and reproducing articulated movements and trajectories.Possible applications include drawing,writing,movement generation,object manipulation,and other tasks where the performance requires human-like interpretation and generalisation capabilities.展开更多
Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper ...Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper puts forward the prediction method using the dynamic seismicity pattern with dynamic implications. This method considers the formation and evolution of the seismic gap on the basis of plate movement and structural characteristics. Through analysis of 26 cases of earthquakes of MS≥5.0 occurring in East China and South China, this paper obtains the relationship between the main shock with seismic gap and active fault's location, as well as the relationship between the seismic gap and location and strike of active faults. Meanwhile, this paper provides a dynamic explanation of the differences in the formation and evolution patterns of the seismic gap between the two regions, thus providing the physical basis for and reducing the uncertainty of predicting earthquakes using the seismic gap method.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11232005 and11472104)the Doctoral Fund of Ministry of Education of China(No.20120074110020)
文摘As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.
文摘Population movement is an important phenomenon in China in recent years. Its mechanism is: (1) thrust of more people and less land in the eastern region of China; (2) attraction of dual economy in the western region of China; (3) national policy on preferential wages and grains for the western region. Population movement has an important effect on the change of regional division pattern in China: by the medium of the moving people, there forms another regional division pattern, i.e. rural industry system based on rural town industry; (2) there forms another profit mechanism compensated from the western region to the eastern region. It not only wins more profit in the eastern region, but also changes dual economy in the western region. Therefore, We should make choice of a comprehensible and encouraging attitude on population movement; a special government organization for general survey of the moving people should be set up at once.
基金This project was supported by Scientific Research Fund of Hebei College of Industry and Technology and also supported by the Natural Science Foundation of Hebei Province(E2017417008).
文摘A three-dimensional semicircle cold model of COREX melter gasifier(MG)was established,and the effects of coke charging pattern on burden movement were investigated by adopting this model.The burden flow pattern of packed bed was measured with different coke charging amounts,coke charging positions,and coke sizes.The results show that the solid flow pattern presents a change from straight line type to reverse U type and finally to W type in MG with traditional coke charging,while the burden flow pattern experiences the change from straight line type to W type with platform and finally W type under center coke charging,and the solid flow pattern presents a change from straight line type to W type with platform and finally W type under intermediate coke charging.The difference demonstrates that coke charging pattern affects the uniform descending in MG to some degree.The burden in the coke charging zone keeps a straight line descending.No matter what kind of coke charging pattern is adopted,the burden residence time is shortened with the increase in coke charging amount,and the vertex of deadman decreases obviously,which is conducive to the renewal of the deadman.The appropriate coke charging amount and coke size should be well controlled at 8.7%and 5 mm,respectively.The results are useful not only in developing further understanding of solid flow in MG but also in verifying different mathematical models,particularly the coupled discrete element method with computational fluid dynamics simulation which has been increasingly used in the literature.
基金The authors thank all volunteers who participated in the study.This work was supported by National Natural Science Foundation of China(Grant No.52005364,52122501)This work was also supported by the Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education(Tianjin University).
文摘Our previous study suggested that the subcutaneous muscle displacement caused by joint movements might alter muscle activation patterns and thus affect the classification performance.To further analyze the effect of joint movements on the online performance of Electromyography(EMG)Pattern Recognition(PR),this study assessed online classification performance with and without joint movements.EMG signals were recorded from the dominant forearm of 10 able-bodied subjects under two motion scenarios:Hand and Wrist Joints Unconstrained(HAWJU)and Constrained(HAWJC).Sixth-order autoregressive coefficients and four time-domain features were extracted from EMG signals.Linear Discriminant Analysis(LDA)models were trained to perform an online performance evaluation of the limb motions.The experimental results showed that the four online performance metrics:Motion Selection Time(MST),Motion Completion Time(MCT),Motion Completion Rate(MCR),and Online Classification Accuracy(ONCA)were 0.35 s,1.44 s,97.40%,and 82.61%for HAWJU and 0.37 s,1.47 s,89.70%,and 73.57%for HAWJC,respectively.The outcomes of this study indicated that subcutaneous muscle displacement due to joint movements has a positive effect on online classification performance.The absence of joint movements may be a physiological factor contributing to the poor online performance of the EMG-PR of transradial amputees.This study can provide a new perspective for improving the online performance of EMG-PR for transradial amputees.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.52005364,52122501)the State Key Laboratory of Mechanical System and Vibration(Grant No.MSV202012)This work was also supported by the Key Laboratory of Mechanism Theory and Equipment Design of the Ministry of Education(Tianjin University).
文摘Electromyography(EMG)pattern recognition has been widely employed for prosthesis control.Several studies demonstrated that amputees had poorer performances of EMG pattern recognition when compared to able-bodied individuals.Several factors,such as the muscle weakness and atrophy of residual limbs,the length of residual limbs,and the decrease of the affected side's motor cortex,had been studied to improve the performance of amputees.However,there was no study on the factor that the absence of joint movements for amputees.This study aimed to investigate whether the hand and wrist joint movements had effects on the EMG pattern recognition.Ten able-bodied subjects were tested for 11 hand and wrist gestures with two different gesture modalities:hand and wrist joints unconstrained(HAWJU)and constrained(HAWJC).Time-domain(TD)features and Linear Discriminant Analysis(LDA)were employed to compare the classification performance of the two modalities.Compared to HAWJU,HAWJC significantly reduced the average Classification Accuracy(CA)across all subjects from 95.53 to 85.52%.The experimental results demonstrated that the hand and wrist joint movements had significant effects on EMG pattern recognition.The outcomes provided a new perspective to study the factors affecting EMG pattern recognition.
基金supported by the National Natural Science Foundation of China under the Youth Project(Grant No.52204087)Additional support was provided by the Science and Technology Research Program of the Chongqing Municipal Education Commission(Grant No.KJQN202200746).
文摘This study focuses on addressing ventilation and dust removal challenges during the construction of small-section tunnels using drilling and blasting techniques.Specifically,the research examines the shale gas gathering and transmission trunk line project in the Weiyuan and Luzhou blocks.To gain deeper insights into dust migration patterns,numerical simulations were conducted.The study further analyzed dust migration behavior in small-section tunnels and large steep-sloped shafts,taking into account various factors such as ventilation distance,tunnel slope,and section size.The results indicate that optimal ventilation occurs at distances of 15 and 13 m.Additionally,dust concentration was notably lower when the tunnel slope was 0°,suggesting that a flat slope is more advantageous for construction projects where the outlet wind speed remains constant.Moreover,as the tunnel’s cross-sectional size increases,dust concentration decreases significantly,further underscoring the benefits of larger tunnel sections in mitigating dust accumulation.
文摘In this paper,multi_quadric equations interpolation is used to establish a widely covered and valuable speed field model,with which the crustal movement image is obtained.
基金National Natural Science Foundation of China （51274205）, the Doctoral Program Foundation of Ministry of Education the New Teacher Project （20070290022） and the Open Project of China University of Mining and Technology Resources and Mine Safety State Key Laboratory （S KLCRSM 10KFB 13）.
文摘The objective of this work is to investigate the influence of smoke movement during mine fires on miner evacuation behaviors. A three-dimensional computational fluid dynamics method was conducted to reconstruct the lane- way conveyor belt fire scenes under two ventilating conditions. The parameters, including temperature-time histories, soot density, carbon monoxide and heat release rate, were simulated to characterize the mine fires at various ventilating speeds. A miner evacuation model affected by fire smoke movement was advanced to describe the miner evacuation behaviors, which can be divided into three stages. Based on the evacuation model coupled with the mine fire smoke movement, the available safety evacuation time for miners involved in coal mine fire located in different sites was estimated. Two evacuation patterns were advanced according to the ventilating speeds combined with the model of miner evacuation behaviors. The results show that the miners located between the inlet-air end and the air door in lane 1 should be evacuated to the inlet-air end and other miners involved in coal mine fire could choose the air door as the escaping destination, when the ventilation speed is greater than 3 m/s. Accordingly, the research can be used as references for the mine safety administration authorities to design the safety evacuation.
基金supported by the National Natural Science Foundation of China (Nos.10872068 and 10672057)the Fundamental Research Fund for the Central Universities
文摘The rhythmic movement is a spontaneous behavior due to the central pattern generator （CPG）. At present, the CPG model only shows the spontaneous behavior, but does not refer to the instruction regulation role of the cerebral cortex. In this paper, a modified model based on the Matsuoka neural oscillator theory is presented to better show the regulation role of the cerebral cortex signal to the CPG neuronal network. The complex interaction between the input signal and other parameters in the CPG network is established, making all parameters of the CPG vary with the input signal. In this way, the effect of the input signal to the CPG network is enhanced so that the CPG network can express the self-regulation movement state instead of being limited to the spontaneous behavior, and thus the regulation role of the cerebral cortex signal can be reflected. Numerical simulation shows that the modified model can generate various movement forms with different modes, frequencies, and interchanges between them. It is revealed in theories that the cerebral cortex signal can regulate the mode and frequency of the gait in the ~ourse of the gait movement.
基金supported by European Community s Seventh Framework Programme FP7/2007-2013,Challenge 2,Cognitive Systems,Interaction,Robotics(No.248311AMARSi)
文摘Articulated movements are fundamental in many human and robotic tasks.While humans can learn and generalise arbitrarily long sequences of movements,and particularly can optimise them to ft the constraints and features of their body,robots are often programmed to execute point-to-point precise but fxed patterns.This study proposes a new approach to interpreting and reproducing articulated and complex trajectories as a set of known robot-based primitives.Instead of achieving accurate reproductions,the proposed approach aims at interpreting data in an agent-centred fashion,according to an agent s primitive movements.The method improves the accuracy of a reproduction with an incremental process that seeks frst a rough approximation by capturing the most essential features of a demonstrated trajectory.Observing the discrepancy between the demonstrated and reproduced trajectories,the process then proceeds with incremental decompositions and new searches in sub-optimal parts of the trajectory.The aim is to achieve an agent-centred interpretation and progressive learning that fts in the frst place the robots capability,as opposed to a data-centred decomposition analysis.Tests on both geometric and human generated trajectories reveal that the use of own primitives results in remarkable robustness and generalisation properties of the method.In particular,because trajectories are understood and abstracted by means of agent-optimised primitives,the method has two main features： 1） Reproduced trajectories are general and represent an abstraction of the data.2） The algorithm is capable of reconstructing highly noisy or corrupted data without pre-processing thanks to an implicit and emergent noise suppression and feature detection.This study suggests a novel bio-inspired approach to interpreting,learning and reproducing articulated movements and trajectories.Possible applications include drawing,writing,movement generation,object manipulation,and other tasks where the performance requires human-like interpretation and generalisation capabilities.
基金supported by the National Science and Technology Program of China Earthquake Administration (No. 2006BAC01B02-01-05)Anhui Provincial Science and Technique Foundation (No. 08010302204)Joint Earthquake Science Fundation (A08077)
文摘Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper puts forward the prediction method using the dynamic seismicity pattern with dynamic implications. This method considers the formation and evolution of the seismic gap on the basis of plate movement and structural characteristics. Through analysis of 26 cases of earthquakes of MS≥5.0 occurring in East China and South China, this paper obtains the relationship between the main shock with seismic gap and active fault's location, as well as the relationship between the seismic gap and location and strike of active faults. Meanwhile, this paper provides a dynamic explanation of the differences in the formation and evolution patterns of the seismic gap between the two regions, thus providing the physical basis for and reducing the uncertainty of predicting earthquakes using the seismic gap method.
