Sparse measurements challenge fault location in distribution networks.This paper proposes a method for asymmetric ground fault location in distribution networks with limited measurements.A virtual injected current vec...Sparse measurements challenge fault location in distribution networks.This paper proposes a method for asymmetric ground fault location in distribution networks with limited measurements.A virtual injected current vector is formulated to estimate the fault line,which can be reconstructed from voltage sags measured at a few buses using compressive sensing(CS).The relationship between the virtual injected current ratio(VICR)and fault position is deduced from circuit analysis to pinpoint the fault.Furthermore,a two-stage recovery strategy is proposed for improving reconstruction accuracy of the current vector,where two different sensing matrixes are utilized to improve the incoherence.The proposed method is validated in IEEE 34 node test feeder.Simulation results show asymmetric ground fault type,resistance,fault position and access of distributed generators(DGs)do not significantly influence performance of our method.In addition,it works effectively under various scenarios of noisy measurement and line parameter error.Validations on 134 node test feeders prove the proposed method is also suitable for systems with more complex structure.展开更多
Counseling people,particularly those in the military engaged in group living,who are in quarantine during the COVID-19 pandemic is a challenge.Therefore,supporting the people in quarantine who are experiencing psy-cho...Counseling people,particularly those in the military engaged in group living,who are in quarantine during the COVID-19 pandemic is a challenge.Therefore,supporting the people in quarantine who are experiencing psy-chological and interpersonal problems has become a new challenge in military mental health.This study’s primary concern was how to overcome the problems caused by physical quarantine.The study subject was a virtual coun-seling network and its operating experience during the quarantine period in Taiwan amidst the global COVID-19 pandemic.For soldiers who mainly live in groups,this study discussed how the virtual counseling network combined with the existing military support group to determine what influence the network had on peo-ple in quarantine.This study found that this group exhibited four types of experiences:togetherness,empathy,confidence,and belonging and cohesion.Such experiences are beneficial for group healing through mutual sup-port and companionship.Collective cohesion and psychological healing can be achieved through a virtual com-munity.This is worthy of attention,particularly in the pandemic or post-pandemic era.Physical isolation has become a fact of life,and such isolation is not just isolation from disease but also between regional boundaries.Counseling and support systems in virtual space or the operation of virtual teams must be considered for the future.展开更多
Mental fatigue is a complex state that results from prolonged cognitive activity. Symptoms of mental fatigue can include change in mood, motivation, and temporary deterioration of various cognitive functions involved ...Mental fatigue is a complex state that results from prolonged cognitive activity. Symptoms of mental fatigue can include change in mood, motivation, and temporary deterioration of various cognitive functions involved in goal-directed behavior. Extensive research has been done to develop methods for recognizing physiological and psychophysiological signs of mental fatigue. This has allowed the development of many AI-based models to classify different levels of fatigue, using data extracted from eye-tracking device, EEG, or ECG. In this paper, we present an experimental protocol which aims to both generate/measure mental fatigue and provide effective strategies for recuperation via VR sessions paired with EEG and eye tracking devices. This paper first provides a comprehensive state-of-the-art of mental fatigue predictive factors, measurement methods, and recuperation strategies. Then the paper presents an experimental protocol resulting from the state-of-the-art to 1) generate and measure mental fatigue and 2) evaluate the effectiveness of virtual therapy for fatigue recuperation, using a virtual reality (VR) simulated environment. In our work, we successfully generated mental fatigue through completion of cognitive tasks in a virtual simulated environment. Participants showed significant decline in pupil diameter and theta/alpha score during the various cognitive tasks. We trained an RBF SVM classifier from Electroencephalogram (EEG) data classifying mental fatigue with 95% accuracy on the test set. Finally, our results show that the time allocated for virtual therapy did not improve pupil diameter in post-relaxation period. Further research on the impact of relaxation therapy on relaxation therapy should allocate time closer to the standard recovery time of 60 min.展开更多
基金supported in part by Key-Area Research and Development Program of Guangdong Province(No.2020B010166004)State Key Program of National Natural Science Foundation of China under Grant(No.U1866210)Natural Science Foundation of Guangdong Province(No.2022A1515011587).
文摘Sparse measurements challenge fault location in distribution networks.This paper proposes a method for asymmetric ground fault location in distribution networks with limited measurements.A virtual injected current vector is formulated to estimate the fault line,which can be reconstructed from voltage sags measured at a few buses using compressive sensing(CS).The relationship between the virtual injected current ratio(VICR)and fault position is deduced from circuit analysis to pinpoint the fault.Furthermore,a two-stage recovery strategy is proposed for improving reconstruction accuracy of the current vector,where two different sensing matrixes are utilized to improve the incoherence.The proposed method is validated in IEEE 34 node test feeder.Simulation results show asymmetric ground fault type,resistance,fault position and access of distributed generators(DGs)do not significantly influence performance of our method.In addition,it works effectively under various scenarios of noisy measurement and line parameter error.Validations on 134 node test feeders prove the proposed method is also suitable for systems with more complex structure.
文摘Counseling people,particularly those in the military engaged in group living,who are in quarantine during the COVID-19 pandemic is a challenge.Therefore,supporting the people in quarantine who are experiencing psy-chological and interpersonal problems has become a new challenge in military mental health.This study’s primary concern was how to overcome the problems caused by physical quarantine.The study subject was a virtual coun-seling network and its operating experience during the quarantine period in Taiwan amidst the global COVID-19 pandemic.For soldiers who mainly live in groups,this study discussed how the virtual counseling network combined with the existing military support group to determine what influence the network had on peo-ple in quarantine.This study found that this group exhibited four types of experiences:togetherness,empathy,confidence,and belonging and cohesion.Such experiences are beneficial for group healing through mutual sup-port and companionship.Collective cohesion and psychological healing can be achieved through a virtual com-munity.This is worthy of attention,particularly in the pandemic or post-pandemic era.Physical isolation has become a fact of life,and such isolation is not just isolation from disease but also between regional boundaries.Counseling and support systems in virtual space or the operation of virtual teams must be considered for the future.
文摘Mental fatigue is a complex state that results from prolonged cognitive activity. Symptoms of mental fatigue can include change in mood, motivation, and temporary deterioration of various cognitive functions involved in goal-directed behavior. Extensive research has been done to develop methods for recognizing physiological and psychophysiological signs of mental fatigue. This has allowed the development of many AI-based models to classify different levels of fatigue, using data extracted from eye-tracking device, EEG, or ECG. In this paper, we present an experimental protocol which aims to both generate/measure mental fatigue and provide effective strategies for recuperation via VR sessions paired with EEG and eye tracking devices. This paper first provides a comprehensive state-of-the-art of mental fatigue predictive factors, measurement methods, and recuperation strategies. Then the paper presents an experimental protocol resulting from the state-of-the-art to 1) generate and measure mental fatigue and 2) evaluate the effectiveness of virtual therapy for fatigue recuperation, using a virtual reality (VR) simulated environment. In our work, we successfully generated mental fatigue through completion of cognitive tasks in a virtual simulated environment. Participants showed significant decline in pupil diameter and theta/alpha score during the various cognitive tasks. We trained an RBF SVM classifier from Electroencephalogram (EEG) data classifying mental fatigue with 95% accuracy on the test set. Finally, our results show that the time allocated for virtual therapy did not improve pupil diameter in post-relaxation period. Further research on the impact of relaxation therapy on relaxation therapy should allocate time closer to the standard recovery time of 60 min.
