Deeply-rooted in China’s popular culture,precious scrolls(Baojuan)are the golden material to display popular religious belief of the mass.Based on the rare texts sorted and annotated by Shang Lixin,Dutch Sinologist W...Deeply-rooted in China’s popular culture,precious scrolls(Baojuan)are the golden material to display popular religious belief of the mass.Based on the rare texts sorted and annotated by Shang Lixin,Dutch Sinologist Wilt L.Idema continues his journey of translating precious scrolls.Focused on the theme of devoted women Buddhist followers in Ming dynasty,he explores the ethical choices of married women in facing the betrayal of servants or concubines.His translations not only add important reading material to Western readers in the field of Chinese popular literature,but also set standard for the coming translators in rendering Chinese ballads.展开更多
A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The eq...A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The equations for working pro- file and pressure angle of the cam are derived based on the inverse model and the derivative of pitch curve of cams.An example is given and demonstrates that it is available to design the new mechanism using the derived expressions.展开更多
With the social media networks development quickly, the followers of the social media network' s behaviors have taken a lot of damagers and threats to national security, and made the nation into unstable situations, ...With the social media networks development quickly, the followers of the social media network' s behaviors have taken a lot of damagers and threats to national security, and made the nation into unstable situations, even subverted the national sovereignty .This paper analyzes the characters of the followers of the social media in the Ira, Tunisia, Egypt and Libya's turmoil, concludes constructive suggestions how to ensure national stability and harmonious development, has some positive effect to our national security.展开更多
There was an outpouring of grief across China on October 30 when fans of legendary wuxia (master of martial arts) novelist Jin Yong heard of his passing at age 94.
In this paper, we are concerned with bilevel programs with multiple followers. Three new solution concepts are introduced for a bilevel programming problem with multiple followers. First, one sufficient condition for ...In this paper, we are concerned with bilevel programs with multiple followers. Three new solution concepts are introduced for a bilevel programming problem with multiple followers. First, one sufficient condition for the existence of a Nash equilibrium reaction is presented and the continuity of the reaction set is discussed. Next, we show that a class of bilevel programs with multiple followers can be solved via solving a corresponding bilevel program with a single follower. Finally on the basis of a theorem proved via applying the Kuhn-Tucker conditions to the inner game problem, a branch and bound technique is developed for bilevel program with multiple followers. Two numerical examples are also given to illustrate the algorithm.展开更多
A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave attenuation.Rigid vegetation canopies with aligned and staggered configurations were tested under the co...A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave attenuation.Rigid vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged scenarios.Results show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current conditions.Moreover,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave conditions.For the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and current.The time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s conditions.With the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the canopy.The vegetation drag coefficients are obtained by a calibration approach.The empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.展开更多
This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the fe...This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.展开更多
The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlle...The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.展开更多
This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensi...This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.展开更多
Approximately 7%of the polyps resected endoscopically have an adenocarcinoma focus,with no previous endoscopic evidence of malignancy.This raises the question of whether endoscopic resection has been curative.Furtherm...Approximately 7%of the polyps resected endoscopically have an adenocarcinoma focus,with no previous endoscopic evidence of malignancy.This raises the question of whether endoscopic resection has been curative.Furthermore,there is no consensus on what the endoscopic and histological criteria for good prognosis are,the appropriate follow-up strategy and what are the long-term results.The aim of the retrospective study by Fábián et al was to evaluate the occurrence of local relapse or distant metastasis in those tumors that were resected endoscopically compared to those that underwent oncologic surgery.They concluded that,regardless of the treatment strategy chosen,there was a higher recurrence rate than described in the literature and that adherence to follow-up was poor.The management approach for an endoscopically benign polyp histologically confirmed as adenocarcinoma depends on the presence of any of the previously described poor prognostic histological factors.If none of these factors are present and the polyp has been completely resected en bloc(R0),active surveillance is considered appropriate as endoscopic resection is deemed curative.These results highlight,once again,the need for further multicentric clinical practice studies to obtain more evidence for the purpose of establishing appropriate treatment and follow-up strategies.展开更多
The SHRP2 Naturalistic Driving Study was used to evaluate the impact of various work zone and driver characteristics on back of queue safety critical events (crash, near-crash, or conflicts) The model included 43 SCE ...The SHRP2 Naturalistic Driving Study was used to evaluate the impact of various work zone and driver characteristics on back of queue safety critical events (crash, near-crash, or conflicts) The model included 43 SCE and 209 “normal” events which were used as controls. The traces included representing 209 unique drivers. A Mixed-Effects Logistic Regression model was developed with probability of a SCE as the response variable and driver and work zone characteristics as predictor variables. The final model indicated glances over 1 second away from the driving task and following closely increased risk of an SCE by 3.8 times and 2.9 times, respectively. Average speed was negatively correlated to crash risk. This is counterintuitive since in most cases, it is expected that higher speeds are related to back of queue crashes. However, most queues form under congested conditions. As a result, vehicles encountering a back of queue would be more likely to be traveling at lower speeds.展开更多
A team is assigned to accomplish a task in each infinitely-repeated period. The guide of the team and his followers are allowed to have asymmetric productivity; also the followers have either a hostile or favorable il...A team is assigned to accomplish a task in each infinitely-repeated period. The guide of the team and his followers are allowed to have asymmetric productivity; also the followers have either a hostile or favorable illusion toward the guide. Re- spective efforts and the followers' illusion are private information. At the end of each period, the output of the joint task emerges and the followers evaluate the guide. The analysis shows (1) that potential for an unreasonable evaluation suppresses the guide's effort down to an average level; (2) letting the followers inform the guide of their il- lusion in advance increases both sides' payoffs; (3) abolishing the evaluation reduces both sides' payoffs in general; and (4) however, if the magnitude of the followers' hos- tile illusion weighted by its relative probability is enormous, abolishing the evaluation increases the output and the guide's payoff.展开更多
Objective:Analyze the relationship between inoculating one case of the COVID-19 inactivated vaccine(Vero cell)and immune thrombocytopenic purpura to provide a reference for the standardized handling of adverse events ...Objective:Analyze the relationship between inoculating one case of the COVID-19 inactivated vaccine(Vero cell)and immune thrombocytopenic purpura to provide a reference for the standardized handling of adverse events following immunization.Methods:According to the"National Monitoring Program for Suspected Adverse Reactions to Vaccinations,"an on-site investigation,data collection and analysis,expert group diagnosis,and medical association assessment were conducted on a case of immune thrombocytopenic purpura in District A of Chongqing after vaccination with the inactivated COVID-19 vaccine.The assessment report was delivered to the three relevant parties,the case was reviewed,and the experience was summarized.Results:The investigation and diagnosis by the district-level vaccination abnormal reaction expert group concluded that the disease that occurred after vaccination with the COVID-19 inactivated vaccine was secondary immune thrombocytopenic purpura,an abnormal reaction to the vaccination.The medical damage was classified as Level II Grade B.The vaccine production enterprise raised objections to this conclusion.After re-assessment by the municipal-level medical association,the conclusion was consistent with that of the district-level medical association.The vaccine production enterprise did not raise any further objections.Conclusion:Through active collaboration among district and municipal-level medical associations,disease control institutions,and vaccination units,the recipients have been promptly and effectively treated,providing financial support for their subsequent treatment and safeguarding their rights.The investigation and disposal procedures for adverse events following immunization in Chongqing are clear,and the mechanism is sound.It is necessary to continue strengthening the monitoring of adverse events following immunization according to the existing plan and to ensure timely and standardized handling.Simultaneously,it is crucial to strengthen vaccine management and vaccination management.展开更多
This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance ...This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results.展开更多
This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with re...This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with respect to the inertial frame,while the path following error is not expected to violate the predefined boundaries.Differently from existing moving path following guidance laws,the proposed method removes complex geometric transformation by formulating the moving path following problem into a second-order time-varying control problem.A nominal moving path following guidance law is designed with disturbances and their derivatives estimated by high-order disturbance observers.To guarantee that the path following error will not exceed the prescribed bounds,a robust control barrier function is developed and incorporated into controller design with quadratic program based framework.The proposed method does not require the initial position of the UAV to be within predefined boundaries.And the safety margin concept makes error-constraint be respected even if in a noisy environment.The proposed guidance law is validated through numerical simulations of shipboard landing and hardware-in-theloop(HIL)experiments.展开更多
To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal po...To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal policy opti-mization(DPPO)algorithm,which is a modified actor-critic-based type of reinforcement learning algorithm,is adapted to improve the controller performance in repeated trials.The LSTM network structure is introduced to solve the strong temporal cor-relation USV control problem.In addition,a specially designed path dataset,including straight and curved paths,is established to simulate various sailing scenarios so that the reinforcement learning controller can obtain as much handling experience as possible.Extensive numerical simulation results demonstrate that the proposed method has better control performance under missions involving complex maneuvers than trained with limited scenarios and can potentially be applied in practice.展开更多
Objective:To access the level of knowledge,perceptions,and practice towards adverse events following immunization(AEFI)surveillance among vaccination workers in Zhejiang province,China.Methods:This was a cross-section...Objective:To access the level of knowledge,perceptions,and practice towards adverse events following immunization(AEFI)surveillance among vaccination workers in Zhejiang province,China.Methods:This was a cross-sectional survey involving 768 vaccination workers.Data were collected using self-administered questionnaires and analyzed by using SAS 9.3 software.Knowledge,perceptions,and practice on AEFI surveillance were summarized using frequency tables.The mean±SD value was used as the cut-off for defining good(values≥mean)and poor(values<mean)knowledge,perceptions or practice.Binary logistic regression analysis was used to determine sociodemographic variables associated with knowledge,perceptions,and practice towards AEFI.Results:The proportions of good knowledge,perceptions and practice on AEFI surveillance were 78.13%,57.81%and 66.15%,respectively.Having a higher education background,longer years of experience,previous training on AEFI and≥30 years of age were factors associated with good knowledge,perceptions and practice on AEFI surveillance among vaccination workers.Conclusions:Over half of the respondents had good knowledge,perceptions and practice on AEFI surveillance work.Interventions on improving the vaccination workers’knowledge,perceptions and practice on AEFI surveillance should be considered in order to develop a more effective surveillance system.展开更多
The single-file movement experiment offered a convenient way to investigate the one-dimensional leader–follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader–...The single-file movement experiment offered a convenient way to investigate the one-dimensional leader–follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader–follower behavior by introducing a time-dependent delayed speed correlation. A total of 118 German students from the fifth grade(aged11–12 years old) and the 11th grade(aged 17–18 years old) participated the single-file experiment. The characteristic delay time for each pedestrian was identified by optimising the time-dependent delayed speed correlation. The influences of the curvature of the experimental scenario, density, age, and gender on the delay time were statistically examined. The results suggested that to a large extent, the revealed characteristic delay time was a density-dependent variable, and none of the curvatures, the age and gender of the individual, and the age and gender of the leader had a significant influence on it. The findings from this study are variable resources to understand the leader–follower behavior among children pedestrians and to build related simulation models.展开更多
A review presents the state-of-the-art path-following control systems for maritime autonomous surface ships,where the special focus is placed on the guidance subsystem and control subsystem.The path following control ...A review presents the state-of-the-art path-following control systems for maritime autonomous surface ships,where the special focus is placed on the guidance subsystem and control subsystem.The path following control system is one of the basic requirements for autonomous ships since it guarantees that the ship can track the predefined path with small crosstrack errors.The path following problem is firstly defined,and the cross-track error dynamics are derived from the kinematic equations of marine surface ships.The classical guidance laws are introduced,and the governing equations are also presented in this paper.A review of the guidance laws and controllers for the maritime autonomous surface ships has been carried out based on relevant journal and conference papers.Several important properties and characteristics,such as control structure,guidance law,control method,stability,environmental disturbance and vessel dynamics,are defined for the comparative analysis.Finally,the summary and a discussion on the most used technologies for the path following control of marine autonomous surface ships are presented and highlighted.展开更多
Objective:To compare the reporting pattern of hearing loss and tinnitus across different vaccines brands used in Malaysia(BNT162b2,CoronaVac,ChAdOx1,Ad5.CoV2-S and BBIBP-CorV).Methods:This retrospective study included...Objective:To compare the reporting pattern of hearing loss and tinnitus across different vaccines brands used in Malaysia(BNT162b2,CoronaVac,ChAdOx1,Ad5.CoV2-S and BBIBP-CorV).Methods:This retrospective study included all reports of hearing loss and tinnitus occurring after COVID-19 vaccination that were received in the national pharmacovigilance database,QUEST,from February 24,2021 through July 31,2022.Reports given causality consistent or indeterminate were included.Results:There were 21 cases of hearing loss,with overall reporting rate of 0.29 cases per million doses.The rate was similar across BNT162b2,CoronaVac and ChAdOx1.For tinnitus,35 cases were reported,with the overall reporting rate of 0.49 cases per million doses,and the highest rate was reported for ChAdOx1.For both events,most cases aged 30 to 49 years.No gender disparity was observed.Both events were mainly reported to have occurred after the primary doses,with a median time-to-onset of two days.There were no statistically significant differences in the reporting patterns for both events across BNT162b2,CoronaVac and ChAdOx1 by age group,gender,race,and dose number.Conclusions:Despite the low reporting rates and insufficient evidence to confirm its relationship,hearing loss and tinnitus following vaccinations should not be ignored due to its disabling potential and impact on one’s quality of life.Continual reporting is encouraged for better signal characterization in the future.展开更多
基金Under a doctoral project endowed by Gansu Provincial Department of Education,China,in 2022(2022QB-164)an innovation project endowed by Gansu Provincial Department of Education,China,in 2023(2023B-208)+1 种基金a humanities and social sciences project endowed by Gansu Federation of Social Science,China,in 2022(22ZC53)a doctoral project endowed by Longdong University,China,in 2022(XYBYSK2201).
文摘Deeply-rooted in China’s popular culture,precious scrolls(Baojuan)are the golden material to display popular religious belief of the mass.Based on the rare texts sorted and annotated by Shang Lixin,Dutch Sinologist Wilt L.Idema continues his journey of translating precious scrolls.Focused on the theme of devoted women Buddhist followers in Ming dynasty,he explores the ethical choices of married women in facing the betrayal of servants or concubines.His translations not only add important reading material to Western readers in the field of Chinese popular literature,but also set standard for the coming translators in rendering Chinese ballads.
文摘A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The equations for working pro- file and pressure angle of the cam are derived based on the inverse model and the derivative of pitch curve of cams.An example is given and demonstrates that it is available to design the new mechanism using the derived expressions.
基金This paper is supported by the National Social Science Foundation Project--Research on Network Association and the Stability and Development of Ethnic Minority Area in China's Borderland--Take Yunnan Area as an example (No. 09CZZ011 ), and the Key Project of Educational Department of Yunnan Province--Research on the policemen working mode guided by intelligence (No. 2010Z089).
文摘With the social media networks development quickly, the followers of the social media network' s behaviors have taken a lot of damagers and threats to national security, and made the nation into unstable situations, even subverted the national sovereignty .This paper analyzes the characters of the followers of the social media in the Ira, Tunisia, Egypt and Libya's turmoil, concludes constructive suggestions how to ensure national stability and harmonious development, has some positive effect to our national security.
文摘There was an outpouring of grief across China on October 30 when fans of legendary wuxia (master of martial arts) novelist Jin Yong heard of his passing at age 94.
文摘In this paper, we are concerned with bilevel programs with multiple followers. Three new solution concepts are introduced for a bilevel programming problem with multiple followers. First, one sufficient condition for the existence of a Nash equilibrium reaction is presented and the continuity of the reaction set is discussed. Next, we show that a class of bilevel programs with multiple followers can be solved via solving a corresponding bilevel program with a single follower. Finally on the basis of a theorem proved via applying the Kuhn-Tucker conditions to the inner game problem, a branch and bound technique is developed for bilevel program with multiple followers. Two numerical examples are also given to illustrate the algorithm.
基金financially supported by the National Key Research and Development Program of China(2023YFC3208501)the National Natural Science Foundation of China(Grant Nos.U2340225,51979172)+2 种基金the Nanjing Hydraulic Research Institute Special Fund for Basic Scientific Research of Central Public Research Institutes(Y223002,Y220013)the CRSRI Open Research Program(Grant No.CKWV20221007/KY)the Post-Three Gorges Sediment Research Project of MWR(ProjectⅢ:Impact and Countermeasures of the Three Gorges Project on the Stability of the Shoal and Channel and Habitat of Yangtze River Estuary)。
文摘A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave attenuation.Rigid vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged scenarios.Results show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current conditions.Moreover,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave conditions.For the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and current.The time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s conditions.With the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the canopy.The vegetation drag coefficients are obtained by a calibration approach.The empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62173312 and 61803348in part by the National Major Scientific Instruments Development Project under Grant No.61927807+3 种基金in part by the Program for the Innovative Talents of Higher Education Institutions of ShanxiShanxi Province Science Foundation for Excellent Youthsin part by the Shanxi"1331 Project"Key Subjects Construction(1331KSC)in part by Graduate Innovation Project of Shanxi Province under Grant No.2021Y617。
文摘This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.
基金supported by the National Natural Science Foundation of China(62073019)。
文摘The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.
基金Project(WPUKFJJ2019-19)supported by the Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,ChinaProject(51974317)supported by the National Natural Science Foundation of China。
文摘This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.
文摘Approximately 7%of the polyps resected endoscopically have an adenocarcinoma focus,with no previous endoscopic evidence of malignancy.This raises the question of whether endoscopic resection has been curative.Furthermore,there is no consensus on what the endoscopic and histological criteria for good prognosis are,the appropriate follow-up strategy and what are the long-term results.The aim of the retrospective study by Fábián et al was to evaluate the occurrence of local relapse or distant metastasis in those tumors that were resected endoscopically compared to those that underwent oncologic surgery.They concluded that,regardless of the treatment strategy chosen,there was a higher recurrence rate than described in the literature and that adherence to follow-up was poor.The management approach for an endoscopically benign polyp histologically confirmed as adenocarcinoma depends on the presence of any of the previously described poor prognostic histological factors.If none of these factors are present and the polyp has been completely resected en bloc(R0),active surveillance is considered appropriate as endoscopic resection is deemed curative.These results highlight,once again,the need for further multicentric clinical practice studies to obtain more evidence for the purpose of establishing appropriate treatment and follow-up strategies.
文摘The SHRP2 Naturalistic Driving Study was used to evaluate the impact of various work zone and driver characteristics on back of queue safety critical events (crash, near-crash, or conflicts) The model included 43 SCE and 209 “normal” events which were used as controls. The traces included representing 209 unique drivers. A Mixed-Effects Logistic Regression model was developed with probability of a SCE as the response variable and driver and work zone characteristics as predictor variables. The final model indicated glances over 1 second away from the driving task and following closely increased risk of an SCE by 3.8 times and 2.9 times, respectively. Average speed was negatively correlated to crash risk. This is counterintuitive since in most cases, it is expected that higher speeds are related to back of queue crashes. However, most queues form under congested conditions. As a result, vehicles encountering a back of queue would be more likely to be traveling at lower speeds.
文摘A team is assigned to accomplish a task in each infinitely-repeated period. The guide of the team and his followers are allowed to have asymmetric productivity; also the followers have either a hostile or favorable illusion toward the guide. Re- spective efforts and the followers' illusion are private information. At the end of each period, the output of the joint task emerges and the followers evaluate the guide. The analysis shows (1) that potential for an unreasonable evaluation suppresses the guide's effort down to an average level; (2) letting the followers inform the guide of their il- lusion in advance increases both sides' payoffs; (3) abolishing the evaluation reduces both sides' payoffs in general; and (4) however, if the magnitude of the followers' hos- tile illusion weighted by its relative probability is enormous, abolishing the evaluation increases the output and the guide's payoff.
文摘Objective:Analyze the relationship between inoculating one case of the COVID-19 inactivated vaccine(Vero cell)and immune thrombocytopenic purpura to provide a reference for the standardized handling of adverse events following immunization.Methods:According to the"National Monitoring Program for Suspected Adverse Reactions to Vaccinations,"an on-site investigation,data collection and analysis,expert group diagnosis,and medical association assessment were conducted on a case of immune thrombocytopenic purpura in District A of Chongqing after vaccination with the inactivated COVID-19 vaccine.The assessment report was delivered to the three relevant parties,the case was reviewed,and the experience was summarized.Results:The investigation and diagnosis by the district-level vaccination abnormal reaction expert group concluded that the disease that occurred after vaccination with the COVID-19 inactivated vaccine was secondary immune thrombocytopenic purpura,an abnormal reaction to the vaccination.The medical damage was classified as Level II Grade B.The vaccine production enterprise raised objections to this conclusion.After re-assessment by the municipal-level medical association,the conclusion was consistent with that of the district-level medical association.The vaccine production enterprise did not raise any further objections.Conclusion:Through active collaboration among district and municipal-level medical associations,disease control institutions,and vaccination units,the recipients have been promptly and effectively treated,providing financial support for their subsequent treatment and safeguarding their rights.The investigation and disposal procedures for adverse events following immunization in Chongqing are clear,and the mechanism is sound.It is necessary to continue strengthening the monitoring of adverse events following immunization according to the existing plan and to ensure timely and standardized handling.Simultaneously,it is crucial to strengthen vaccine management and vaccination management.
基金supported in part by the National Natural Science Foundation of China(61825305,62171274,U1933125,U2241228,62273019)the Shanghai Science and Technology Major Project(2021SHZDZX)+2 种基金the National Natural Science Foundation of China through the Main Research Projecton Machine Behavior and Human-Machine Collaborated Decision Making Methodology(72192820)the Third Research Projecton Human Behavior in HumanMachine Collaboration(72192822)the China Postdoctoral Science Foundation(2022M710093)。
文摘This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results.
基金supported in part by the National Natural Science Foundations of China(62173016,62073019)the Fundamental Research Funds for the Central Universities(YWF-23-JC-04,YWF-23-JC-02)。
文摘This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with respect to the inertial frame,while the path following error is not expected to violate the predefined boundaries.Differently from existing moving path following guidance laws,the proposed method removes complex geometric transformation by formulating the moving path following problem into a second-order time-varying control problem.A nominal moving path following guidance law is designed with disturbances and their derivatives estimated by high-order disturbance observers.To guarantee that the path following error will not exceed the prescribed bounds,a robust control barrier function is developed and incorporated into controller design with quadratic program based framework.The proposed method does not require the initial position of the UAV to be within predefined boundaries.And the safety margin concept makes error-constraint be respected even if in a noisy environment.The proposed guidance law is validated through numerical simulations of shipboard landing and hardware-in-theloop(HIL)experiments.
基金supported by the National Natural Science Foundation(61601491)the Natural Science Foundation of Hubei Province(2018CFC865)the China Postdoctoral Science Foundation Funded Project(2016T45686).
文摘To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal policy opti-mization(DPPO)algorithm,which is a modified actor-critic-based type of reinforcement learning algorithm,is adapted to improve the controller performance in repeated trials.The LSTM network structure is introduced to solve the strong temporal cor-relation USV control problem.In addition,a specially designed path dataset,including straight and curved paths,is established to simulate various sailing scenarios so that the reinforcement learning controller can obtain as much handling experience as possible.Extensive numerical simulation results demonstrate that the proposed method has better control performance under missions involving complex maneuvers than trained with limited scenarios and can potentially be applied in practice.
基金funded by medical and health science and technology project of Zhejiang province (Grant number:2023KY633)
文摘Objective:To access the level of knowledge,perceptions,and practice towards adverse events following immunization(AEFI)surveillance among vaccination workers in Zhejiang province,China.Methods:This was a cross-sectional survey involving 768 vaccination workers.Data were collected using self-administered questionnaires and analyzed by using SAS 9.3 software.Knowledge,perceptions,and practice on AEFI surveillance were summarized using frequency tables.The mean±SD value was used as the cut-off for defining good(values≥mean)and poor(values<mean)knowledge,perceptions or practice.Binary logistic regression analysis was used to determine sociodemographic variables associated with knowledge,perceptions,and practice towards AEFI.Results:The proportions of good knowledge,perceptions and practice on AEFI surveillance were 78.13%,57.81%and 66.15%,respectively.Having a higher education background,longer years of experience,previous training on AEFI and≥30 years of age were factors associated with good knowledge,perceptions and practice on AEFI surveillance among vaccination workers.Conclusions:Over half of the respondents had good knowledge,perceptions and practice on AEFI surveillance work.Interventions on improving the vaccination workers’knowledge,perceptions and practice on AEFI surveillance should be considered in order to develop a more effective surveillance system.
基金supported by the National Natural Science Foundation of China (Grant Nos. 71901175, 71901060, and 72101276)。
文摘The single-file movement experiment offered a convenient way to investigate the one-dimensional leader–follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader–follower behavior by introducing a time-dependent delayed speed correlation. A total of 118 German students from the fifth grade(aged11–12 years old) and the 11th grade(aged 17–18 years old) participated the single-file experiment. The characteristic delay time for each pedestrian was identified by optimising the time-dependent delayed speed correlation. The influences of the curvature of the experimental scenario, density, age, and gender on the delay time were statistically examined. The results suggested that to a large extent, the revealed characteristic delay time was a density-dependent variable, and none of the curvatures, the age and gender of the individual, and the age and gender of the leader had a significant influence on it. The findings from this study are variable resources to understand the leader–follower behavior among children pedestrians and to build related simulation models.
文摘A review presents the state-of-the-art path-following control systems for maritime autonomous surface ships,where the special focus is placed on the guidance subsystem and control subsystem.The path following control system is one of the basic requirements for autonomous ships since it guarantees that the ship can track the predefined path with small crosstrack errors.The path following problem is firstly defined,and the cross-track error dynamics are derived from the kinematic equations of marine surface ships.The classical guidance laws are introduced,and the governing equations are also presented in this paper.A review of the guidance laws and controllers for the maritime autonomous surface ships has been carried out based on relevant journal and conference papers.Several important properties and characteristics,such as control structure,guidance law,control method,stability,environmental disturbance and vessel dynamics,are defined for the comparative analysis.Finally,the summary and a discussion on the most used technologies for the path following control of marine autonomous surface ships are presented and highlighted.
文摘Objective:To compare the reporting pattern of hearing loss and tinnitus across different vaccines brands used in Malaysia(BNT162b2,CoronaVac,ChAdOx1,Ad5.CoV2-S and BBIBP-CorV).Methods:This retrospective study included all reports of hearing loss and tinnitus occurring after COVID-19 vaccination that were received in the national pharmacovigilance database,QUEST,from February 24,2021 through July 31,2022.Reports given causality consistent or indeterminate were included.Results:There were 21 cases of hearing loss,with overall reporting rate of 0.29 cases per million doses.The rate was similar across BNT162b2,CoronaVac and ChAdOx1.For tinnitus,35 cases were reported,with the overall reporting rate of 0.49 cases per million doses,and the highest rate was reported for ChAdOx1.For both events,most cases aged 30 to 49 years.No gender disparity was observed.Both events were mainly reported to have occurred after the primary doses,with a median time-to-onset of two days.There were no statistically significant differences in the reporting patterns for both events across BNT162b2,CoronaVac and ChAdOx1 by age group,gender,race,and dose number.Conclusions:Despite the low reporting rates and insufficient evidence to confirm its relationship,hearing loss and tinnitus following vaccinations should not be ignored due to its disabling potential and impact on one’s quality of life.Continual reporting is encouraged for better signal characterization in the future.