Early exiting has shown significant potential in accelerating the inference of pre-trained language models(PLMs)by allowing easy samples to exit from shallow layers.However,existing early exiting methods primarily rel...Early exiting has shown significant potential in accelerating the inference of pre-trained language models(PLMs)by allowing easy samples to exit from shallow layers.However,existing early exiting methods primarily rely on local information from individual samples to estimate prediction uncertainty for making exiting decisions,overlooking the global information provided by the sample population.This impacts the estimation of prediction uncertainty,compromising the reliability of exiting de-cisions.To remedy this,inspired by principal component analysis(PCA),the authors define a residual score to capture the deviation of features from the principal space of the sample population,providing a global perspective for estimating prediction uncertainty.Building on this,a two-stage exiting strategy is proposed that integrates global information from residual scores with local information from energy scores at both the decision and feature levels.This strategy incorporates three-way decisions to enable more reliable exiting decisions for boundary region samples by delaying judgement.Extensive experiments on the GLUE benchmark validate that the method achieves an average speed-up ratio of 2.17×across all tasks with minimal per-formance degradation.Additionally,it surpasses the state-of-the-art E-LANG by 11%in model acceleration,along with a performance improvement of 0.6 points,demonstrating a better performance-efficiency trade-off.展开更多
Given the explosive growth in video content generation,there is a rising demand for efficient and scalable video recognition.Deep learning has shown its remarkable performance in video analytics,by applying 2D or 3D C...Given the explosive growth in video content generation,there is a rising demand for efficient and scalable video recognition.Deep learning has shown its remarkable performance in video analytics,by applying 2D or 3D Convolutional Neural Networks(CNNs)across multiple video frames.However,high data quantities,intensive computational costs,and various performance requirements restrict the deployment and application of these video-oriented models on resource-constrained edge devices,e.g.,Internet-of-Things(IoT)and mobile devices.To tackle this issue,we propose a joint optimization system RSEE by adaptive Resolution Selection(RS)and conditional Early Exiting(EE)to facilitate efficient video recognition based on 2D CNN backbones.Given a video frame,RSEE firstly determines what input resolution is to be used for processing by the dynamic resolution selector,then sends the resolution-adjusted frame into the backbone network to extract features,and finally determines whether to stop further processing based on the accumulated features of current video at the early-exiting gate.Extensive experiments conducted on benchmark datasets indicate that RSEE remarkably outperforms current state-of-the-art solutions in terms of computational cost(by up to 84.72%on UCF101 and 78.93%on HMDB51)and inference speed(up to 3.18×on UCF101 and 3.50×on HMDB51),while still preserving competitive recognition accuracy(up to 7.81%on UCF1017.21%on HMDB51).Furthermore,the superiority of RSEE on resource-constrained edge devices is validated on the NVIDIA Jetson Nano,with processing speeds controlled by hyperparameters ranging from about 12 to 60 Frame-Per-Second(FPS)that well enable real-time analysis.展开更多
Roundabouts are becoming a preferred form of intersection control type due to their safety and capacity benefits. Yield control at roundabout entries inherently reduces fuel consumption and emissions when compared to ...Roundabouts are becoming a preferred form of intersection control type due to their safety and capacity benefits. Yield control at roundabout entries inherently reduces fuel consumption and emissions when compared to other conventional intersection types. However, these benefits can be limited by poor driver behavior and judgment when entering the roundabout. This research addresses the nature of gap distributions and use of turn indicators by exiting vehicles at three single-lane roundabouts in Vermont, New York, and Alaska. Presented here is a comparison of vehicle headways measured at two different locations in each roundabout. Rejected headways are analyzed in the context of priority abstaining events when entering drivers yield to vehicles exiting on the same leg of the roundabout suggesting that ＂true＂ critical gaps are being overestimated. Results indicate that exiting vehicles, particularly those that do not use their turn indicators when departing from the major-stream of traffic have an influence on the entry decision of drivers on the same approach. This behavior is of particular concern for intersection efficiency （i.e., delay） and sustainability （i.e., excess fuel consumption and emissions）. Results prompt the consideration of more consistent guidance on and enforcement of turn indicator use during roundabout negotiations.展开更多
This study investigates the hydrodynamic process of a cylinder ejected from the water’s surface through high-speed camera experiments.Using digital image processing methods,the images obtained through experiments are...This study investigates the hydrodynamic process of a cylinder ejected from the water’s surface through high-speed camera experiments.Using digital image processing methods,the images obtained through experiments are processed and analyzed.Although the dynamics of rising buoyant cylinders have been thoroughly investigated,the pop-up height of the cylinders has not been extensively explored.Statistical analysis of the kinematic and dynamic data of cylinders is conducted.Research has shown that after the cylinder rises,it pops out of the water’s surface.Within the experimental range,the pop-up height of the cylinder is related to the release depth.Furthermore,the pop-up height and release depth of the cylinder vary linearly under vertical release conditions.Under horizontal release conditions,the relationship between pop-up height and release depth shows irregular changes mainly because of the unstable shedding of the wake vortex.展开更多
The paper addresses the impacts of political exits on capital structure policies,through studying the impact of the Brexit deal on the UK's companies listed at FTSE 100 as a practical case.The study is divided int...The paper addresses the impacts of political exits on capital structure policies,through studying the impact of the Brexit deal on the UK's companies listed at FTSE 100 as a practical case.The study is divided into two periods:the first before the Brexit deal(2010-2015)and the second after the referendum until Brexit(2016-2021).Data were collected from the annual reports of the UK companies and the FTSE 100 database.Moreover,capital structure policies were studied by analyzing the determinants such as long-term debt over total equity,profitability,tangibility,liquidity,propensity to pay dividends,size,and political factor-Brexit.The results show that there is a direct relationship between political exits and capital structure.Also,the results show that the financial ratios are different between the two periods(before and after Brexit),where it seems that the capital structure variables were affected starting from the referendum period,political negotiations between the two parties,and then Brexit(2016-2021).In addition,the correlation matrix shows that long-term debt over total equity has a negative correlation with profitability,liquidity,and political factors,where it seems that long-term debt over total equity has a positive correlation with tangibility,size,and paying dividends.Moreover,the results show that political shocks were affecting the FTSE 100 performance starting from 2016 until 2021.The study could be useful for financial and economic academics.Moreover,the study could be helpful for EU members and the UK government,taking into consideration the interests of the UK and EU where any future policies or laws will affect the financial and economic sectors of the two parties.展开更多
In order to better predict the traffic states on freeways and make management decisions,a hybrid model of support vector machine(SVM)and K-nearest neighbor(KNN)is proposed for shortterm freeway exiting volume predicti...In order to better predict the traffic states on freeways and make management decisions,a hybrid model of support vector machine(SVM)and K-nearest neighbor(KNN)is proposed for shortterm freeway exiting volume prediction.First,a historical data set is built by using the freeway toll data.The abnormal toll records,such as records that have same entry and exit station,illogical time record and abnormal travel speed,are excluded by data quality control.Based on the historical dataset,it is found that the exiting volume has periodical variation over time which provides the basis of the short-term prediction.Then,the historical data set is cross-classified into twelves groups based on the day of week and time of day.The prediction has been done for each group.Finally,the prediction is accomplished by the hybrid-model of SVM and KNN.The exiting volumes of previous time periods are used as the feature vector for KNN and SVM.Besides,a dynamic weight is adopted for the prediction of current time period based on the latest prediction accuracy of KNN and SVM.The model results indicate that the proposed algorithm is feasible and accurate.The Mean Absolute Percentage Error is under 10%.When comparing with the results of single KNN or SVM method,the results show that the combination of KNN and SVM can improve the reliability of the prediction significantly.The proposed method can be implemented in the on-line application of exiting volume prediction,which is able to consider different vehicle types.展开更多
Using the approach of D. Landriault et al. and B. Li and X. Zhou, for a one-dimensional time-homogeneous diffusion process X and constants c 〈 a 〈 b 〈 d, we find expressions of double Laplace transforms of the form...Using the approach of D. Landriault et al. and B. Li and X. Zhou, for a one-dimensional time-homogeneous diffusion process X and constants c 〈 a 〈 b 〈 d, we find expressions of double Laplace transforms of the form Ex[e--θTd--λ∫o Td1a 〈Xs〈b ds; Td 〈 Tc], where Tx denotes the first passage time of level x. As applications, we find explicit Laplace transforms of the corresponding occupation time and occupation density for the Brownian motion with two-valued drift and that of occupation time for the skew Ornstein- Uhlenbeck process, respectively. Some known results are also recovered.展开更多
The main challenge in AI governance today is striking a balance between controlling AI dangers and fostering AI innovation.Regulators in a number of nations have progressively extended the regulatory sandbox,which was...The main challenge in AI governance today is striking a balance between controlling AI dangers and fostering AI innovation.Regulators in a number of nations have progressively extended the regulatory sandbox,which was first implemented in the banking sector,to AI governance in an effort to reduce the conflict between regulation and innovation.The AI regulatory sandbox is a new and feasible route for AI governance in China that not only helps to manage the risks of technology application but also prevents inhibiting AI innovation.It keeps inventors'trial-and-error tolerance space inside the regulatory purview while offering a controlled setting for the development and testing of novel AI that hasn't yet been put on the market.By providing full-cycle governance of AI with the principles of agility and inclusive prudence,the regulatory sandbox offers an alternative to the conventional top-down hard regulation,expost regulation,and tight regulation.However,the current system also has inherent limitations and practical obstacles that need to be overcome by a more rational and effective approach.To achieve its positive impact on AI governance,the AI regulatory sandbox system should build and improve the access and exit mechanism,the coordination mechanism between the sandbox and personal information protection,and the mechanisms of exemption,disclosure,and communication.展开更多
This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elim...This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power supply.This method effectively reduces the residual grounding current.To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was designed.An online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection locations.Furthermore,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time.Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults.Compared to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.展开更多
Experiments are conducted on the evacuation rate of pedestrians through exits with queued evacuation pattern and random evacuation pattern. The experimental results show that the flow rate of pedestrians is larger wit...Experiments are conducted on the evacuation rate of pedestrians through exits with queued evacuation pattern and random evacuation pattern. The experimental results show that the flow rate of pedestrians is larger with the random evacuation pattern than with the queued evacuation pattern. Therefore, the exit width calculated based on the minimum evacuation clear width for every 100 persons, which is on the assumption that the pedestrians pass through the exit in one queue or several queues, is conservative. The number of people crossing the exit simultaneously is greater in the random evacuation experiments than in the queued evacuation experiments, and the time interval between the front row and rear row of people is shortened in large-exit conditions when pedestrians evacuate randomly. The difference between the flow rate with a queued evacuation pattern and the flow rate with a random evacuation pattern is related to the surplus width of the exit, which is greater than the total width of all accommodated people streams. Two dimensionless quantities are defined to explore this relationship. It is found that the difference in flow rate between the two evacuation patterns is stable at a low level when the surplus width of the exit is no more than 45% of the width of a single pedestrian stream. There is a great difference between the flow rate with the queued evacuation pattern and the flow rate with the random evacuation pattern in a scenario with a larger surplus width of the exit. Meanwhile, the pedestrians crowd extraordinarily at the exit in these conditions as well, since the number of pedestrians who want to evacuate through exit simultaneously greatly exceeds the accommodated level. Therefore, the surplus width of exit should be limited especially in the narrow exit condition, and the relationship between the two dimensionless quantities mentioned above could provide the basis to some extent.展开更多
Heat and mass transfer of a circular-shaped porous moist object inside a two-dimensional triangle cavity is investigated by using finite element method.The porous object is considered to be a moist food sample,located...Heat and mass transfer of a circular-shaped porous moist object inside a two-dimensional triangle cavity is investigated by using finite element method.The porous object is considered to be a moist food sample,located in the middle of the cavity with inlet and outlet ports with different configurations of inlet/outlet ports.Convective drying performance is numerically assessed for different values of Reynolds numbers(between 50 and 250),dry air inlet temperature(between 40 and 80℃)and different locations of the port.It is observed that changing the port locations has significant impacts on the flow recirculaitons inside the triangular chamber while convective drying performance is highly affected.The moisture content reduces with longer time and for higher Reynolds number(Re)values.Case P4 where inlet and outlet ports are in the middle of the walls provides the most effective configuration in terms of convective drying performance while the worst case is seen for P1 case where inlet and outlet are closer to the corners of the chamber.There is a 192% difference between the moisture reduction of these two cases at Re=250,T=80℃ and t=120 min.展开更多
Ensuring adequate access to truck parking is critical to the safe and efficient movement of freight traffic. There are strict federal guidelines for commercial truck driver rest periods. Rest areas and private truck s...Ensuring adequate access to truck parking is critical to the safe and efficient movement of freight traffic. There are strict federal guidelines for commercial truck driver rest periods. Rest areas and private truck stops are the only places for the trucks to stop legally and safely. In locations without sufficient parking areas, trucks often park on interstate ramps, which create safety risks for other interstate motorists. Historically, agencies have employed costly and time intensive manual counting methods, camera surveillance, and driver surveys to assess truck parking. Connected truck data, available in near real-time, offers an efficient alternative to practitioners to assess truck parking patterns and identify areas where there may be insufficient safe parking spaces. This paper presents a case study of interstate I-70 in east central Indiana and documents the observed spatiotemporal impacts of a rest area closure on truck parking on nearby interstate ramps. Results showed that there was a 28% increase in parking on ramps during the rest area closure. Analysis also found that ramps closest to the rest area were most impacted by the closure, seeing a rise in truck parking sessions as high as 2.7 times. Parking duration on the ramps during rest area closure also increased drastically. Although it was expected that this would result in increased parking by trucks on adjacent ramps, this before, during, after scenario provided an ideal scenario to evaluate the robustness of these techniques to assess changing parking characteristics of long-haul commercial trucks. The data analytics and visualization tools presented in this study are scalable nationwide and will aid stakeholders in informed data-driven decision making when allocating resources towards improving the nations commercial vehicle parking infrastructure.展开更多
There has been widespread cooperation and intervention by the international community in the reconstruction of post-conflict countries,and maintaining security and stability and assistance for economic recovery and de...There has been widespread cooperation and intervention by the international community in the reconstruction of post-conflict countries,and maintaining security and stability and assistance for economic recovery and development have been positioned as two indispensable wheels(Security-Development Nexus)in the rebuilding process of unstable countries.One of the most typical examples of the international community's involvement in post-conflict state-building was its support for Afghanistan after 2002.However,despite its efforts over 20 years,the Taliban seized all of Afghanistan in 2021,resulting in the collapse of 20 years of international community support for the building of a democratic state.This paper attempts to recapitulate the international community’s ambitious 20-year Security and Development efforts in Afghanistan,where the resulting failure lies and what lessons can be learned.The key points are:(1)the limitations of the UN’s role and the fact that it had continued to provide assistance without a clear“exit strategy”,(2)the security circle and the development circle had different objectives,and their collaboration was not effectively conducted,(3)the failure to include Taliban in the initial political process of the new state.展开更多
Tunnels are vital in connecting crucial transportation hubs as transportation infrastructure evolves.Variations in tunnel design standards and driving conditions across different levels directly impact driver visual p...Tunnels are vital in connecting crucial transportation hubs as transportation infrastructure evolves.Variations in tunnel design standards and driving conditions across different levels directly impact driver visual perception and traffic safety.This study employs a Gaussian hybrid clustering machine learning model to explore driver gaze patterns in highway tunnels and exits.By utilizing contour coefficients,the optimal number of classification clusters is determined.Analysis of driver visual behavior across tunnel levels,focusing on gaze point distribution,gaze duration,and sweep speed,was conducted.Findings indicate freeway tunnel exits exhibit three distinct fixation point categories aligning with Gaussian distribution,while highway tunnels display four such characteristics.Notably,in both tunnel types,65%of driver gaze is concentrated on the near area ahead of their lane.Differences emerge in highway tunnels due to oncoming traffic,leading to 13.47%more fixation points and 0.9%increased fixation time in the right lane compared to regular highway tunnel conditions.Moreover,scanning speeds predominantly fall within the 0.25-0.3 range,accounting for 75.47%and 31.14%of the total sweep speed.展开更多
EXIT(EXtrinsic Information Transfer)图分析方法可以看作密度进化技术的一种简化,具有实现简单的优点,并且在不同的信道、调制方案以及检测器中都可以使用。在详细阐述了EXIT图分析方法的基础上,给出了基于EXIT图的正则LDPC码的门限...EXIT(EXtrinsic Information Transfer)图分析方法可以看作密度进化技术的一种简化,具有实现简单的优点,并且在不同的信道、调制方案以及检测器中都可以使用。在详细阐述了EXIT图分析方法的基础上,给出了基于EXIT图的正则LDPC码的门限判决算法,进一步通过计算机仿真分别给出了变量节点译码器和校验节点译码器的EXIT曲线,以及不同的信道信噪比下(3,6)正则LDPC码EXIT图的变化规律,直观地对迭代译码过程中的互信息变化进行了描述分析。展开更多
基金supported by the National Natural Science Foundation of China(No.62376198)the National Key Research and Development Program of China(No.2022YFB3104700)the Shanghai Baiyulan Pujiang Project(No.08002360429).
文摘Early exiting has shown significant potential in accelerating the inference of pre-trained language models(PLMs)by allowing easy samples to exit from shallow layers.However,existing early exiting methods primarily rely on local information from individual samples to estimate prediction uncertainty for making exiting decisions,overlooking the global information provided by the sample population.This impacts the estimation of prediction uncertainty,compromising the reliability of exiting de-cisions.To remedy this,inspired by principal component analysis(PCA),the authors define a residual score to capture the deviation of features from the principal space of the sample population,providing a global perspective for estimating prediction uncertainty.Building on this,a two-stage exiting strategy is proposed that integrates global information from residual scores with local information from energy scores at both the decision and feature levels.This strategy incorporates three-way decisions to enable more reliable exiting decisions for boundary region samples by delaying judgement.Extensive experiments on the GLUE benchmark validate that the method achieves an average speed-up ratio of 2.17×across all tasks with minimal per-formance degradation.Additionally,it surpasses the state-of-the-art E-LANG by 11%in model acceleration,along with a performance improvement of 0.6 points,demonstrating a better performance-efficiency trade-off.
基金supported by the National Science Foundation of China(No.62172031)the Beijing Municipal Natural Science Foundation(No.L191019).
文摘Given the explosive growth in video content generation,there is a rising demand for efficient and scalable video recognition.Deep learning has shown its remarkable performance in video analytics,by applying 2D or 3D Convolutional Neural Networks(CNNs)across multiple video frames.However,high data quantities,intensive computational costs,and various performance requirements restrict the deployment and application of these video-oriented models on resource-constrained edge devices,e.g.,Internet-of-Things(IoT)and mobile devices.To tackle this issue,we propose a joint optimization system RSEE by adaptive Resolution Selection(RS)and conditional Early Exiting(EE)to facilitate efficient video recognition based on 2D CNN backbones.Given a video frame,RSEE firstly determines what input resolution is to be used for processing by the dynamic resolution selector,then sends the resolution-adjusted frame into the backbone network to extract features,and finally determines whether to stop further processing based on the accumulated features of current video at the early-exiting gate.Extensive experiments conducted on benchmark datasets indicate that RSEE remarkably outperforms current state-of-the-art solutions in terms of computational cost(by up to 84.72%on UCF101 and 78.93%on HMDB51)and inference speed(up to 3.18×on UCF101 and 3.50×on HMDB51),while still preserving competitive recognition accuracy(up to 7.81%on UCF1017.21%on HMDB51).Furthermore,the superiority of RSEE on resource-constrained edge devices is validated on the NVIDIA Jetson Nano,with processing speeds controlled by hyperparameters ranging from about 12 to 60 Frame-Per-Second(FPS)that well enable real-time analysis.
文摘Roundabouts are becoming a preferred form of intersection control type due to their safety and capacity benefits. Yield control at roundabout entries inherently reduces fuel consumption and emissions when compared to other conventional intersection types. However, these benefits can be limited by poor driver behavior and judgment when entering the roundabout. This research addresses the nature of gap distributions and use of turn indicators by exiting vehicles at three single-lane roundabouts in Vermont, New York, and Alaska. Presented here is a comparison of vehicle headways measured at two different locations in each roundabout. Rejected headways are analyzed in the context of priority abstaining events when entering drivers yield to vehicles exiting on the same leg of the roundabout suggesting that ＂true＂ critical gaps are being overestimated. Results indicate that exiting vehicles, particularly those that do not use their turn indicators when departing from the major-stream of traffic have an influence on the entry decision of drivers on the same approach. This behavior is of particular concern for intersection efficiency （i.e., delay） and sustainability （i.e., excess fuel consumption and emissions）. Results prompt the consideration of more consistent guidance on and enforcement of turn indicator use during roundabout negotiations.
基金supported in part by the National Natural Science Foundation of China under Grant No.41706108the Science and Technology Commission of Shanghai Municipality Project 20dz1206600+2 种基金the Natural Science Foundation of Shanghai under Grant No.20ZR1424800the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University under Grant No.SL2022ZD106the Natural Science Foundation of Chongqing under Grant No.cstc2021jcyj-msxmX0650.
文摘This study investigates the hydrodynamic process of a cylinder ejected from the water’s surface through high-speed camera experiments.Using digital image processing methods,the images obtained through experiments are processed and analyzed.Although the dynamics of rising buoyant cylinders have been thoroughly investigated,the pop-up height of the cylinders has not been extensively explored.Statistical analysis of the kinematic and dynamic data of cylinders is conducted.Research has shown that after the cylinder rises,it pops out of the water’s surface.Within the experimental range,the pop-up height of the cylinder is related to the release depth.Furthermore,the pop-up height and release depth of the cylinder vary linearly under vertical release conditions.Under horizontal release conditions,the relationship between pop-up height and release depth shows irregular changes mainly because of the unstable shedding of the wake vortex.
文摘The paper addresses the impacts of political exits on capital structure policies,through studying the impact of the Brexit deal on the UK's companies listed at FTSE 100 as a practical case.The study is divided into two periods:the first before the Brexit deal(2010-2015)and the second after the referendum until Brexit(2016-2021).Data were collected from the annual reports of the UK companies and the FTSE 100 database.Moreover,capital structure policies were studied by analyzing the determinants such as long-term debt over total equity,profitability,tangibility,liquidity,propensity to pay dividends,size,and political factor-Brexit.The results show that there is a direct relationship between political exits and capital structure.Also,the results show that the financial ratios are different between the two periods(before and after Brexit),where it seems that the capital structure variables were affected starting from the referendum period,political negotiations between the two parties,and then Brexit(2016-2021).In addition,the correlation matrix shows that long-term debt over total equity has a negative correlation with profitability,liquidity,and political factors,where it seems that long-term debt over total equity has a positive correlation with tangibility,size,and paying dividends.Moreover,the results show that political shocks were affecting the FTSE 100 performance starting from 2016 until 2021.The study could be useful for financial and economic academics.Moreover,the study could be helpful for EU members and the UK government,taking into consideration the interests of the UK and EU where any future policies or laws will affect the financial and economic sectors of the two parties.
文摘In order to better predict the traffic states on freeways and make management decisions,a hybrid model of support vector machine(SVM)and K-nearest neighbor(KNN)is proposed for shortterm freeway exiting volume prediction.First,a historical data set is built by using the freeway toll data.The abnormal toll records,such as records that have same entry and exit station,illogical time record and abnormal travel speed,are excluded by data quality control.Based on the historical dataset,it is found that the exiting volume has periodical variation over time which provides the basis of the short-term prediction.Then,the historical data set is cross-classified into twelves groups based on the day of week and time of day.The prediction has been done for each group.Finally,the prediction is accomplished by the hybrid-model of SVM and KNN.The exiting volumes of previous time periods are used as the feature vector for KNN and SVM.Besides,a dynamic weight is adopted for the prediction of current time period based on the latest prediction accuracy of KNN and SVM.The model results indicate that the proposed algorithm is feasible and accurate.The Mean Absolute Percentage Error is under 10%.When comparing with the results of single KNN or SVM method,the results show that the combination of KNN and SVM can improve the reliability of the prediction significantly.The proposed method can be implemented in the on-line application of exiting volume prediction,which is able to consider different vehicle types.
基金Acknowledgements The authors thank the anonymous referees for helpful comments. Yingqiu Li＇s work was supported by the National Natural Science Foundation of China （Grant No. 11171044） und the Natural Science Foundation of Hunan Province （Grant No. llJ32001） Suxin Wang＇s work was supported by the Natural Sciences and Engineering Research Council of Canada.
文摘Using the approach of D. Landriault et al. and B. Li and X. Zhou, for a one-dimensional time-homogeneous diffusion process X and constants c 〈 a 〈 b 〈 d, we find expressions of double Laplace transforms of the form Ex[e--θTd--λ∫o Td1a 〈Xs〈b ds; Td 〈 Tc], where Tx denotes the first passage time of level x. As applications, we find explicit Laplace transforms of the corresponding occupation time and occupation density for the Brownian motion with two-valued drift and that of occupation time for the skew Ornstein- Uhlenbeck process, respectively. Some known results are also recovered.
文摘The main challenge in AI governance today is striking a balance between controlling AI dangers and fostering AI innovation.Regulators in a number of nations have progressively extended the regulatory sandbox,which was first implemented in the banking sector,to AI governance in an effort to reduce the conflict between regulation and innovation.The AI regulatory sandbox is a new and feasible route for AI governance in China that not only helps to manage the risks of technology application but also prevents inhibiting AI innovation.It keeps inventors'trial-and-error tolerance space inside the regulatory purview while offering a controlled setting for the development and testing of novel AI that hasn't yet been put on the market.By providing full-cycle governance of AI with the principles of agility and inclusive prudence,the regulatory sandbox offers an alternative to the conventional top-down hard regulation,expost regulation,and tight regulation.However,the current system also has inherent limitations and practical obstacles that need to be overcome by a more rational and effective approach.To achieve its positive impact on AI governance,the AI regulatory sandbox system should build and improve the access and exit mechanism,the coordination mechanism between the sandbox and personal information protection,and the mechanisms of exemption,disclosure,and communication.
基金the Natural Science Foundation of Fujian,China(No.2021J01633).
文摘This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power supply.This method effectively reduces the residual grounding current.To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was designed.An online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection locations.Furthermore,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time.Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults.Compared to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.
基金Project supported by the Special Funds for Basic Operating Expenses of the Centre University of China (Grant No.23ZYJS006)。
文摘Experiments are conducted on the evacuation rate of pedestrians through exits with queued evacuation pattern and random evacuation pattern. The experimental results show that the flow rate of pedestrians is larger with the random evacuation pattern than with the queued evacuation pattern. Therefore, the exit width calculated based on the minimum evacuation clear width for every 100 persons, which is on the assumption that the pedestrians pass through the exit in one queue or several queues, is conservative. The number of people crossing the exit simultaneously is greater in the random evacuation experiments than in the queued evacuation experiments, and the time interval between the front row and rear row of people is shortened in large-exit conditions when pedestrians evacuate randomly. The difference between the flow rate with a queued evacuation pattern and the flow rate with a random evacuation pattern is related to the surplus width of the exit, which is greater than the total width of all accommodated people streams. Two dimensionless quantities are defined to explore this relationship. It is found that the difference in flow rate between the two evacuation patterns is stable at a low level when the surplus width of the exit is no more than 45% of the width of a single pedestrian stream. There is a great difference between the flow rate with the queued evacuation pattern and the flow rate with the random evacuation pattern in a scenario with a larger surplus width of the exit. Meanwhile, the pedestrians crowd extraordinarily at the exit in these conditions as well, since the number of pedestrians who want to evacuate through exit simultaneously greatly exceeds the accommodated level. Therefore, the surplus width of exit should be limited especially in the narrow exit condition, and the relationship between the two dimensionless quantities mentioned above could provide the basis to some extent.
文摘Heat and mass transfer of a circular-shaped porous moist object inside a two-dimensional triangle cavity is investigated by using finite element method.The porous object is considered to be a moist food sample,located in the middle of the cavity with inlet and outlet ports with different configurations of inlet/outlet ports.Convective drying performance is numerically assessed for different values of Reynolds numbers(between 50 and 250),dry air inlet temperature(between 40 and 80℃)and different locations of the port.It is observed that changing the port locations has significant impacts on the flow recirculaitons inside the triangular chamber while convective drying performance is highly affected.The moisture content reduces with longer time and for higher Reynolds number(Re)values.Case P4 where inlet and outlet ports are in the middle of the walls provides the most effective configuration in terms of convective drying performance while the worst case is seen for P1 case where inlet and outlet are closer to the corners of the chamber.There is a 192% difference between the moisture reduction of these two cases at Re=250,T=80℃ and t=120 min.
文摘Ensuring adequate access to truck parking is critical to the safe and efficient movement of freight traffic. There are strict federal guidelines for commercial truck driver rest periods. Rest areas and private truck stops are the only places for the trucks to stop legally and safely. In locations without sufficient parking areas, trucks often park on interstate ramps, which create safety risks for other interstate motorists. Historically, agencies have employed costly and time intensive manual counting methods, camera surveillance, and driver surveys to assess truck parking. Connected truck data, available in near real-time, offers an efficient alternative to practitioners to assess truck parking patterns and identify areas where there may be insufficient safe parking spaces. This paper presents a case study of interstate I-70 in east central Indiana and documents the observed spatiotemporal impacts of a rest area closure on truck parking on nearby interstate ramps. Results showed that there was a 28% increase in parking on ramps during the rest area closure. Analysis also found that ramps closest to the rest area were most impacted by the closure, seeing a rise in truck parking sessions as high as 2.7 times. Parking duration on the ramps during rest area closure also increased drastically. Although it was expected that this would result in increased parking by trucks on adjacent ramps, this before, during, after scenario provided an ideal scenario to evaluate the robustness of these techniques to assess changing parking characteristics of long-haul commercial trucks. The data analytics and visualization tools presented in this study are scalable nationwide and will aid stakeholders in informed data-driven decision making when allocating resources towards improving the nations commercial vehicle parking infrastructure.
文摘There has been widespread cooperation and intervention by the international community in the reconstruction of post-conflict countries,and maintaining security and stability and assistance for economic recovery and development have been positioned as two indispensable wheels(Security-Development Nexus)in the rebuilding process of unstable countries.One of the most typical examples of the international community's involvement in post-conflict state-building was its support for Afghanistan after 2002.However,despite its efforts over 20 years,the Taliban seized all of Afghanistan in 2021,resulting in the collapse of 20 years of international community support for the building of a democratic state.This paper attempts to recapitulate the international community’s ambitious 20-year Security and Development efforts in Afghanistan,where the resulting failure lies and what lessons can be learned.The key points are:(1)the limitations of the UN’s role and the fact that it had continued to provide assistance without a clear“exit strategy”,(2)the security circle and the development circle had different objectives,and their collaboration was not effectively conducted,(3)the failure to include Taliban in the initial political process of the new state.
基金supported by the National Natural Science Foundation of China(52302437)the Cangzhou Science and Technology Plan Project(213101011)+1 种基金the Science and Technology Program Projects of Shandong Provincial Department of Transportation(2024B28)the Doctoral Scientific Research Start-up Foundation of Shandong University of Technology(422049).
文摘Tunnels are vital in connecting crucial transportation hubs as transportation infrastructure evolves.Variations in tunnel design standards and driving conditions across different levels directly impact driver visual perception and traffic safety.This study employs a Gaussian hybrid clustering machine learning model to explore driver gaze patterns in highway tunnels and exits.By utilizing contour coefficients,the optimal number of classification clusters is determined.Analysis of driver visual behavior across tunnel levels,focusing on gaze point distribution,gaze duration,and sweep speed,was conducted.Findings indicate freeway tunnel exits exhibit three distinct fixation point categories aligning with Gaussian distribution,while highway tunnels display four such characteristics.Notably,in both tunnel types,65%of driver gaze is concentrated on the near area ahead of their lane.Differences emerge in highway tunnels due to oncoming traffic,leading to 13.47%more fixation points and 0.9%increased fixation time in the right lane compared to regular highway tunnel conditions.Moreover,scanning speeds predominantly fall within the 0.25-0.3 range,accounting for 75.47%and 31.14%of the total sweep speed.
文摘EXIT(EXtrinsic Information Transfer)图分析方法可以看作密度进化技术的一种简化,具有实现简单的优点,并且在不同的信道、调制方案以及检测器中都可以使用。在详细阐述了EXIT图分析方法的基础上,给出了基于EXIT图的正则LDPC码的门限判决算法,进一步通过计算机仿真分别给出了变量节点译码器和校验节点译码器的EXIT曲线,以及不同的信道信噪比下(3,6)正则LDPC码EXIT图的变化规律,直观地对迭代译码过程中的互信息变化进行了描述分析。
