As carrier aircraft sortie frequency and flight deck operational density increase,autonomous dispatch trajectory planning for carrier-based vehicles demands efficient,safe,and kinematically feasible solutions.This pap...As carrier aircraft sortie frequency and flight deck operational density increase,autonomous dispatch trajectory planning for carrier-based vehicles demands efficient,safe,and kinematically feasible solutions.This paper presents an Iterative Safe Dispatch Corridor(iSDC)framework,addressing the suboptimality of the traditional SDC method caused by static corridor construction and redundant obstacle exploration.First,a Kinodynamic-Informed-Bidirectional Rapidly-exploring Random Tree Star(KIBRRT^(*))algorithm is proposed for the front-end coarse planning.By integrating bidirectional tree expansion,goal-biased elliptical sampling,and artificial potential field guidance,it reduces unnecessary exploration near concave obstacles and generates kinematically admissible paths.Secondly,the traditional SDC is implemented in an iterative manner,and the obtained trajectory in the current iteration is fed into the next iteration for corridor generation,thus progressively improving the quality of withincorridor constraints.For tractors,a reverse-motion penalty function is incorporated into the back-end optimizer to prioritize forward driving,aligning with mechanical constraints and human operational preferences.Numerical validations on the data of Gerald R.Ford-class carrier demonstrate that the KIBRRT^(*)reduces average computational time by 75%and expansion nodes by 25%compared to conventional RRT^(*)algorithms.Meanwhile,the iSDC framework yields more time-efficient trajectories for both carrier aircraft and tractors,with the dispatch time reduced by 31.3%and tractor reverse motion proportion decreased by 23.4%relative to traditional SDC.The presented framework offers a scalable solution for autonomous dispatch in confined and safety-critical environment,and an illustrative animation is available at bilibili.com/video/BV1tZ7Zz6Eyz.Moreover,the framework can be easily extended to three-dimension scenarios,and thus applicable for trajectory planning of aerial and underwater vehicles.展开更多
The Hainan FTP is a game changer,and those who seize the opportunities it offers early will be in an advantageous position As it provides a vital new model for China’s international trade and logistics,the Hainan Fre...The Hainan FTP is a game changer,and those who seize the opportunities it offers early will be in an advantageous position As it provides a vital new model for China’s international trade and logistics,the Hainan Free Trade Port(FTP)stands out among similar opening-up initiatives.展开更多
Generating dynamically feasible trajectory for fixed-wing Unmanned Aerial Vehicles(UAVs)in dense obstacle environments remains computationally intractable.This paper proposes a Safe Flight Corridor constrained Sequent...Generating dynamically feasible trajectory for fixed-wing Unmanned Aerial Vehicles(UAVs)in dense obstacle environments remains computationally intractable.This paper proposes a Safe Flight Corridor constrained Sequential Convex Programming(SFC-SCP)to improve the computation efficiency and reliability of trajectory generation.SFC-SCP combines the front-end convex polyhedron SFC construction and back-end SCP-based trajectory optimization.A Sparse A^(*)Search(SAS)driven SFC construction method is designed to efficiently generate polyhedron SFC according to the geometric relation among obstacles and collision-free waypoints.Via transforming the nonconvex obstacle-avoidance constraints to linear inequality constraints,SFC can mitigate infeasibility of trajectory planning and reduce computation complexity.Then,SCP casts the nonlinear trajectory optimization subject to SFC into convex programming subproblems to decrease the problem complexity.In addition,a convex optimizer based on interior point method is customized,where the search direction is calculated via successive elimination to further improve efficiency.Simulation experiments on dense obstacle scenarios show that SFC-SCP can generate dynamically feasible safe trajectory rapidly.Comparative studies with state-of-the-art SCP-based methods demonstrate the efficiency and reliability merits of SFC-SCP.Besides,the customized convex optimizer outperforms off-the-shelf optimizers in terms of computation time.展开更多
Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the ...Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.展开更多
Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. Thi...Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. This is done by examining the acetabular placement in instances of hip dislocation after total hip arthroplasty (THA). Methodology: The authors searched 2653 patient records from 2015 to 2022 looking for patients who had total hip arthroplasty at our facility. For the analysis, 23 patients were culled from 64 individuals who exhibited post-THA dislocations, employing a stringent exclusion criterion, and the resultant acetabular angulation and anteversion were quantified utilizing PEEKMED software (Peek Health S.A., Portugal) upon radiographic evidence. Results: Within the operational timeframe, from the cohort of 2653 subjects, 64 presented with at least a singular incident of displacement. Post-exclusion criterion enforcement, 23 patients were eligible for inclusion. Of these, 10 patients conformed to the safe zone demarcated by Lewinnek for both inclination and anteversion angles, while 13 exhibited deviations from the prescribed anteversion and/or inclination benchmarks. Conclusion: Analysis of the 23 patients reveals that 13 did not confirm to be in the safe zone parameters for anteversion and/or inclination, whereas 10 were within the safe zone as per Lewinnek’s guidelines. This investigative review, corroborated by extant literature, suggests that the isolated consideration of the Lewinnek safe zone does not suffice as a solitary protective factor. It further posits that additional variables are equally critical as acetabular positioning and mandate individual assessment.展开更多
Grasping is one of the most fundamental operations in modern robotics applications.While deep rein-forcement learning(DRL)has demonstrated strong potential in robotics,there is too much emphasis on maximizing the cumu...Grasping is one of the most fundamental operations in modern robotics applications.While deep rein-forcement learning(DRL)has demonstrated strong potential in robotics,there is too much emphasis on maximizing the cumulative reward in executing tasks,and the potential safety risks are often ignored.In this paper,an optimization method based on safe reinforcement learning(Safe RL)is proposed to address the robotic grasping problem under safety constraints.Specifically,considering the obstacle avoidance constraints of the system,the grasping problem of the manipulator is modeled as a Constrained Markov Decision Process(CMDP).The Lagrange multiplier and a dynamic weighted mechanism are introduced into the Proximal Policy Optimization(PPO)framework,leading to the development of the dynamic weighted Lagrange PPO(DWL-PPO)algorithm.The behavior of violating safety constraints is punished while the policy is optimized in this proposed method.In addition,the orientation control of the end-effector is included in the reward function,and a compound reward function adapted to changes in pose is designed.Ultimately,the efficacy and advantages of the suggested method are proved by extensive training and testing in the Pybullet simulator.The results of grasping experiments reveal that the recommended approach provides superior safety and efficiency compared with other advanced RL methods and achieves a good trade-off between model learning and risk aversion.展开更多
With the increasingly turbulent political situation and the outbreak of public health events without warning,it will not only affect people’s physical health,but also affect the global financial market,causing the ma...With the increasingly turbulent political situation and the outbreak of public health events without warning,it will not only affect people’s physical health,but also affect the global financial market,causing the market to fall into a huge crisis,thus leading to a continued decline in the worldwide economy.During periods of financial market turmoil,many investors fall into panic and urgently need a“haven”to protect their assets.With the rise of the digital economy,gold no longer seems to be the only safe-haven option.Bitcoin has gradually entered the investors’field of vision.Some investors believe that Bitcoin can become an emerging safe-haven asset that is as important as or surpasses gold.Based on an analysis of the safe-haven properties of Bitcoin and gold during major political and historical events and public health events,this article will clarify which of the two is more suitable as a reliable contemporary safe-haven asset and provide advice to investors.展开更多
Urbanization develops with the goal of establishing improved and more sustainable habitats for residents.Environmental and social performance must be simultaneously monitored to ascertain whether regions are progressi...Urbanization develops with the goal of establishing improved and more sustainable habitats for residents.Environmental and social performance must be simultaneously monitored to ascertain whether regions are progressing towards or deviating from the safe and just space(SJS)in urbanization.Despite relevant studies,the absence of indicators that bridge ecological preservation and human well-beings renders dual monitoring challenging.This study bridged the gap by exploring the interactions between urbanization,ecosystem services(ESs),and basic water,energy,and food(WEF)needs within the SJS framework across China and its provinces.By quantifying the minimum and actual demands for freshwater withdrawal,carbon emissions,phosphorus emissions,and land use,as well as the supply of ESs into unified biophysical indicators,we found that:(1)China can meet the basic WEF needs for all from 2000 to 2020,but only water and land provisioning ESs can operate within the SJS.Carbon emissions surpassed the sequestration capacity in 2010,while phosphorus purification ES has consistently been unsafe.(2)The SJS performance in terms of ecological and social fulfilment exhibited scale differences and undergone changes with urbanization.Overall,no province in China can consistently operate within all SJSs.(3)In the process of urbanization,improvements in ecological protection and production practices in most provinces expanded the size of SJS,but the continuous increase in total demand failed to steer regions toward safer spaces.Our framework emphasized the common but differentiated pathways that regions at varying stages of urbanization navigate to achieve safety and justice.It also provides an applicable solution for regions aiming to pursue urban growth while maintaining ecological conservation and social justice,ultimately achieving sustainable development.展开更多
Objective:To explore the application effect of bundle management in the safe nursing of patients with autoimmune encephalitis.Methods:Seventy-five patients with autoimmune encephalitis who met the inclusion criteria i...Objective:To explore the application effect of bundle management in the safe nursing of patients with autoimmune encephalitis.Methods:Seventy-five patients with autoimmune encephalitis who met the inclusion criteria in our hospital from January 2024 to June 2024 were randomly divided into two groups:an observation group of 39 patients and a control group of 36 patients.The control group received routine nursing care,while the observation group implemented a bundle management strategy based on routine nursing care.Safety nursing outcomes,clinical symptom improvement time,hospital stay,and neurologic function recovery were observed in both groups.Results:The incidence of adverse events in the observation group was 12.82%,significantly lower than the 33.33%in the control group,with a statistically significant difference(P<0.05).There was no statistically significant difference in restraint usage and ICU transfer rates between the two groups(P>0.05).The clinical symptom improvement time,hospital stay,and neurologic function recovery in the observation group were significantly better than those in the control group,with a statistically significant difference(P<0.05).Conclusion:Through the bundle management model,effective connections can be ensured in various aspects of treatment and rehabilitation for patients with autoimmune encephalitis,providing patients with comprehensive and multi-level nursing services and improving their overall satisfaction and treatment effectiveness.展开更多
Objective:Nurses must follow safe injection practices to prevent healthcare-associated infections(HAIs).This study aimed to identify the risk factors for safe injection practice among nurses in general hospitals.Metho...Objective:Nurses must follow safe injection practices to prevent healthcare-associated infections(HAIs).This study aimed to identify the risk factors for safe injection practice among nurses in general hospitals.Methods:This cross-sectional study included 215 nurses employed in Korean general hospitals.Data were collected from September 22 to October 9,2023.Multiple linear regression analysis was performed using SPSS Statistics 27.0.Results:The regression analysis revealed that a higher level of patient safety priority in the patient safety culture perception,increased knowledge of safe injection practices,and fewer working hours per week were associated with improved performance of safe injection practices among general hospital nurses.Conclusions:To enhance the performance of general hospital nurses in safe injection practice,it is necessary to establish a patient safety culture so that nurses recognize patient safety as a top priority.Additionally,an effective educational program is needed to increase the practical knowledge of safe injection practices,along with a supportive working environment that ensures appropriate working hours to prevent patient safety incidents.展开更多
Safe and just operating spaces(SJOS)are influenced by complex cross-scale interactions and cascading effects spanning global,regional,and local landscape scales.However,existing SJOS research has often focused on sing...Safe and just operating spaces(SJOS)are influenced by complex cross-scale interactions and cascading effects spanning global,regional,and local landscape scales.However,existing SJOS research has often focused on single-scale assessments,overlooking the impacts of multiscale interactions and within-region heterogeneity on urban SJOS.To address this gap,we developed a cross-scale framework for assessing urban SJOS,explicitly incorporating top-down influences from upper-level constraints and bottom-up effects from lower-level heterogeneity.This approach was applied to China's five major metropolises to examine the states and cross-scale dynamics influencing urban SJOS between 1990 and 2020.Our findings reveal that the SJOS of China's metropolises were primarily influenced by factors at national and local landscape scales,with weaker influences from the global and continental scales.A persistent trade-off between social justice and environmental safety was identified across spatiotemporal scales.For instance,Chongqing in southwestern China lagged behind the eastern four metropolises in social performance but exhibited stronger environmental safety due to its extensive natural landscapes,which mitigated the anthropogenic impacts of urban centers.Regional issues,such as the overshoot of PM_(2.5)and ecological footprints(EF),were primarily driven by the bottom-up accumulation of localized pressures,while the overshoot of CO_(2)was attributed to national policy constraints and the universal exceedance of safe thresholds across scales.Addressing urban sustainability requires avoiding adverse cascading effects from other levels by emphasizing landscape heterogeneity within metropolises and fostering coordinated collaboration across scales,particularly at the regional landscape and national levels.展开更多
Semi-supervised clustering techniques attempt to improve clustering accuracy by utilizing a limited number of labeled data for guidance.This method effectively integrates prior knowledge using pre-labeled data.While s...Semi-supervised clustering techniques attempt to improve clustering accuracy by utilizing a limited number of labeled data for guidance.This method effectively integrates prior knowledge using pre-labeled data.While semi-supervised fuzzy clustering(SSFC)methods leverage limited labeled data to enhance accuracy,they remain highly susceptible to inappropriate or mislabeled prior knowledge,especially in noisy or overlapping datasets where cluster boundaries are ambiguous.To enhance the effectiveness of clustering algorithms,it is essential to leverage labeled data while ensuring the safety of the previous knowledge.Existing solutions,such as the Trusted Safe Semi-Supervised Fuzzy Clustering Method(TS3FCM),struggle with random centroid initialization,fixed neighbor radius formulas,and handling outliers or noise at cluster overlaps.A new framework called Active Safe Semi-Supervised Fuzzy Clustering with Pairwise Constraints Based on Cluster Boundary(AS3FCPC)is proposed in this paper to deal with these problems.It does this by combining pairwise constraints and active learning.AS3FCPC uses active learning to query only the most informative data instances close to the cluster boundaries.It also uses pairwise constraints to enforce the cluster structure,which makes the system more accurate and robust.Extensive test results on diverse datasets,including challenging noisy and overlapping scenarios,demonstrate that AS3FCPC consistently achieves superior performance compared to state-of-the-art methods like TS3FCM and other baselines,especially when the data is noisy and overlaps.This significant improvement underscores AS3FCPC’s potential for reliable and accurate semisupervised fuzzy clustering in complex,real-world applications,particularly by effectively managing mislabeled data and ambiguous cluster boundaries.展开更多
Investing in cryptocurrencies is progressively becoming a norm;however,these assets are excessively volatile and often decrease or increase in value instantly.Thus,rational investors holding cryptocurrencies for exten...Investing in cryptocurrencies is progressively becoming a norm;however,these assets are excessively volatile and often decrease or increase in value instantly.Thus,rational investors holding cryptocurrencies for extended periods firmly search for assets that can diversify their risk,preferably with assets other than cryptocurrencies.In this study,we consider the two most studied cryptocurrencies with the highest capitalization and trading volume/value,namely Bitcoin and Ethereum.Specifically,we examine whether high-performing leading US tech stocks(Facebook,Amazon,Apple,Netflix,Google[FAANG])can provide any diversification benefits to cryptocurrency investors.To do so,we employ dynamic conditional correlation(DCC),asymmetric DCC,time-varying parameter vector autoregression-based connectedness measures,dynamic correlation-based hedge and safe-haven regression analyses,portfolio optimization and hedging strategies,time-and frequency-based wavelet coherence,and high-frequency 10-min intraday data from January 1,2018 to January 31,2023.We find that FAANG stocks can be considered(at least weak)safe havens for Bitcoin and Ethereum during the sample period.Our subperiod analyses reveal that the safehaven role of FAANG stocks,specifically for Bitcoin,has noticeably increased.While the safe-haven property of Facebook is the most promising,for Netflix it is blurred between a weak–safe-haven and a hedge.Our findings may help investors,policymakers,and academicians to invest in cryptocurrencies,formulate relevant investment guidelines,and extend the literature on cryptocurrencies,respectively.展开更多
IN the Shanghai Jewish Refugees Museum,a beautiful handbag is waiting for its owner in a display cabinet.The handbag belongs to a Jewish couple.When they sought refuge in Shanghai during World War II,they pawned the h...IN the Shanghai Jewish Refugees Museum,a beautiful handbag is waiting for its owner in a display cabinet.The handbag belongs to a Jewish couple.When they sought refuge in Shanghai during World War II,they pawned the handbag to Jin Wenzhen’s grandfather in exchange for their child’s medical expenses.He lent the couple the cash equivalent of one month’s revenue from his rice shop,but then never saw them again.展开更多
Against the backdrop of the global push for environmental protection and the reduction of plastic pollution,the research and development of alternatives to daily disposable plastic products such as straws have become ...Against the backdrop of the global push for environmental protection and the reduction of plastic pollution,the research and development of alternatives to daily disposable plastic products such as straws have become a hot topic in the environmental protection field.Traditional plastic straws are difficult to degrade,imposing a severe burden on the environment.Meanwhile,existing alternatives like paper straws and PLA(polylactic acid)straws also have numerous drawbacks.展开更多
Low visibility conditions,particularly those caused by fog,significantly affect road safety and reduce drivers’ability to see ahead clearly.The conventional approaches used to address this problem primarily rely on i...Low visibility conditions,particularly those caused by fog,significantly affect road safety and reduce drivers’ability to see ahead clearly.The conventional approaches used to address this problem primarily rely on instrument-based and fixed-threshold-based theoretical frameworks,which face challenges in adaptability and demonstrate lower performance under varying environmental conditions.To overcome these challenges,we propose a real-time visibility estimation model that leverages roadside CCTV cameras to monitor and identify visibility levels under different weather conditions.The proposedmethod begins by identifying specific regions of interest(ROI)in the CCTVimages and focuses on extracting specific features such as the number of lines and contours detected within these regions.These features are then provided as an input to the proposed hierarchical clusteringmodel,which classifies them into different visibility levels without the need for predefined rules and threshold values.In the proposed approach,we used two different distance similaritymetrics,namely dynamic time warping(DTW)and Euclidean distance,alongside the proposed hierarchical clustering model and noted its performance in terms of numerous evaluation measures.The proposed model achieved an average accuracy of 97.81%,precision of 91.31%,recall of 91.25%,and F1-score of 91.27% using theDTWdistancemetric.We also conducted experiments for other deep learning(DL)-based models used in the literature and compared their performances with the proposed model.The experimental results demonstrate that the proposedmodel ismore adaptable and consistent compared to themethods used in the literature.The proposedmethod provides drivers real-time and accurate visibility information and enhances road safety during low visibility conditions.展开更多
With the civilization and modernization of human society,occupational health has emerged as a fundamental goal of social justice,as highlighted in the United Nations'Sustainable Development Goals(SDGs)since 2016.S...With the civilization and modernization of human society,occupational health has emerged as a fundamental goal of social justice,as highlighted in the United Nations'Sustainable Development Goals(SDGs)since 2016.Specifically,"SDG Goal 1:No Poverty","SDG 3:Good Health and Well-being",and"SDG 8:Decent Work and Economic Growth",are interconnected with other SDGs to support the pursuit of occupational health.展开更多
基金support of the National Key Research and Development Plan(Grant No.2021YFB3302501)the financial support of the National Science Foundation of China(Grant No.12161076)the financial support of the Fundamental Research Funds for the Central Universities(Grant No.DUT24LAB129).
文摘As carrier aircraft sortie frequency and flight deck operational density increase,autonomous dispatch trajectory planning for carrier-based vehicles demands efficient,safe,and kinematically feasible solutions.This paper presents an Iterative Safe Dispatch Corridor(iSDC)framework,addressing the suboptimality of the traditional SDC method caused by static corridor construction and redundant obstacle exploration.First,a Kinodynamic-Informed-Bidirectional Rapidly-exploring Random Tree Star(KIBRRT^(*))algorithm is proposed for the front-end coarse planning.By integrating bidirectional tree expansion,goal-biased elliptical sampling,and artificial potential field guidance,it reduces unnecessary exploration near concave obstacles and generates kinematically admissible paths.Secondly,the traditional SDC is implemented in an iterative manner,and the obtained trajectory in the current iteration is fed into the next iteration for corridor generation,thus progressively improving the quality of withincorridor constraints.For tractors,a reverse-motion penalty function is incorporated into the back-end optimizer to prioritize forward driving,aligning with mechanical constraints and human operational preferences.Numerical validations on the data of Gerald R.Ford-class carrier demonstrate that the KIBRRT^(*)reduces average computational time by 75%and expansion nodes by 25%compared to conventional RRT^(*)algorithms.Meanwhile,the iSDC framework yields more time-efficient trajectories for both carrier aircraft and tractors,with the dispatch time reduced by 31.3%and tractor reverse motion proportion decreased by 23.4%relative to traditional SDC.The presented framework offers a scalable solution for autonomous dispatch in confined and safety-critical environment,and an illustrative animation is available at bilibili.com/video/BV1tZ7Zz6Eyz.Moreover,the framework can be easily extended to three-dimension scenarios,and thus applicable for trajectory planning of aerial and underwater vehicles.
文摘The Hainan FTP is a game changer,and those who seize the opportunities it offers early will be in an advantageous position As it provides a vital new model for China’s international trade and logistics,the Hainan Free Trade Port(FTP)stands out among similar opening-up initiatives.
基金supported by the National Natural Science Foundation of China(No.62203256)。
文摘Generating dynamically feasible trajectory for fixed-wing Unmanned Aerial Vehicles(UAVs)in dense obstacle environments remains computationally intractable.This paper proposes a Safe Flight Corridor constrained Sequential Convex Programming(SFC-SCP)to improve the computation efficiency and reliability of trajectory generation.SFC-SCP combines the front-end convex polyhedron SFC construction and back-end SCP-based trajectory optimization.A Sparse A^(*)Search(SAS)driven SFC construction method is designed to efficiently generate polyhedron SFC according to the geometric relation among obstacles and collision-free waypoints.Via transforming the nonconvex obstacle-avoidance constraints to linear inequality constraints,SFC can mitigate infeasibility of trajectory planning and reduce computation complexity.Then,SCP casts the nonlinear trajectory optimization subject to SFC into convex programming subproblems to decrease the problem complexity.In addition,a convex optimizer based on interior point method is customized,where the search direction is calculated via successive elimination to further improve efficiency.Simulation experiments on dense obstacle scenarios show that SFC-SCP can generate dynamically feasible safe trajectory rapidly.Comparative studies with state-of-the-art SCP-based methods demonstrate the efficiency and reliability merits of SFC-SCP.Besides,the customized convex optimizer outperforms off-the-shelf optimizers in terms of computation time.
基金jointly funded by the guangxi Science and Technology Base and Talent Project(AD23026104)the Key Research and Development Program Project in Guangxi(AB23026121)。
文摘Due to the influence of karst cave development and route selection,the location relationship between concealed karst cave and tunnel is more random.In order to explore the influence rule of karst cave location on the minimum safe thickness of water-proof rock mass,a simplified calculation model of water-proof rock mass thickness when the karst cave is located at any location around the tunnel is established,and the influence of multiple factors on the overall stability of water-proof rock mass is considered.Based on the cusp catastrophe theory,the analytical expressions for the safety thickness of waterproof rock mass are derived.Based on the finite difference principle,the analytical expressions of the safety thickness of water-proof rock mass are verified.In order to improve the application range of the analytical formula derived in this paper,the analytical formula is optimized based on the instability principle differences between the simplified calculation model and the elastic compressive bar.The research results show that the necessary condition solution is more applicable and much safer than the sufficient condition solution.Tectonic stress,rock beam length and karst cave water pressure are significantly positively correlated with the safe thickness of the waterproof rock mass.The calculated results of the semioptimized formula and the unoptimized formula are constant values,independent of the karst cave location.While the calculated results of the fully optimized formula are variable values,correlated with the karst cave location,the thickness of the waterproof rock mass gradually decreases as the karst cave location moves from the top of the tunnel to the bottom of the tunnel.The unoptimized formula does not consider the influence of the lateral force of the rock beam,and is not suitable for the working condition with large lateral force,the calculation results of the semi-optimized formula and the fully optimized formula are not very different and are biased to safety,so it can be given priority.
文摘Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. This is done by examining the acetabular placement in instances of hip dislocation after total hip arthroplasty (THA). Methodology: The authors searched 2653 patient records from 2015 to 2022 looking for patients who had total hip arthroplasty at our facility. For the analysis, 23 patients were culled from 64 individuals who exhibited post-THA dislocations, employing a stringent exclusion criterion, and the resultant acetabular angulation and anteversion were quantified utilizing PEEKMED software (Peek Health S.A., Portugal) upon radiographic evidence. Results: Within the operational timeframe, from the cohort of 2653 subjects, 64 presented with at least a singular incident of displacement. Post-exclusion criterion enforcement, 23 patients were eligible for inclusion. Of these, 10 patients conformed to the safe zone demarcated by Lewinnek for both inclination and anteversion angles, while 13 exhibited deviations from the prescribed anteversion and/or inclination benchmarks. Conclusion: Analysis of the 23 patients reveals that 13 did not confirm to be in the safe zone parameters for anteversion and/or inclination, whereas 10 were within the safe zone as per Lewinnek’s guidelines. This investigative review, corroborated by extant literature, suggests that the isolated consideration of the Lewinnek safe zone does not suffice as a solitary protective factor. It further posits that additional variables are equally critical as acetabular positioning and mandate individual assessment.
文摘Grasping is one of the most fundamental operations in modern robotics applications.While deep rein-forcement learning(DRL)has demonstrated strong potential in robotics,there is too much emphasis on maximizing the cumulative reward in executing tasks,and the potential safety risks are often ignored.In this paper,an optimization method based on safe reinforcement learning(Safe RL)is proposed to address the robotic grasping problem under safety constraints.Specifically,considering the obstacle avoidance constraints of the system,the grasping problem of the manipulator is modeled as a Constrained Markov Decision Process(CMDP).The Lagrange multiplier and a dynamic weighted mechanism are introduced into the Proximal Policy Optimization(PPO)framework,leading to the development of the dynamic weighted Lagrange PPO(DWL-PPO)algorithm.The behavior of violating safety constraints is punished while the policy is optimized in this proposed method.In addition,the orientation control of the end-effector is included in the reward function,and a compound reward function adapted to changes in pose is designed.Ultimately,the efficacy and advantages of the suggested method are proved by extensive training and testing in the Pybullet simulator.The results of grasping experiments reveal that the recommended approach provides superior safety and efficiency compared with other advanced RL methods and achieves a good trade-off between model learning and risk aversion.
文摘With the increasingly turbulent political situation and the outbreak of public health events without warning,it will not only affect people’s physical health,but also affect the global financial market,causing the market to fall into a huge crisis,thus leading to a continued decline in the worldwide economy.During periods of financial market turmoil,many investors fall into panic and urgently need a“haven”to protect their assets.With the rise of the digital economy,gold no longer seems to be the only safe-haven option.Bitcoin has gradually entered the investors’field of vision.Some investors believe that Bitcoin can become an emerging safe-haven asset that is as important as or surpasses gold.Based on an analysis of the safe-haven properties of Bitcoin and gold during major political and historical events and public health events,this article will clarify which of the two is more suitable as a reliable contemporary safe-haven asset and provide advice to investors.
基金supported by Postdoctoral Fellowship Program of CPSF(Grant No.GZB20240816)China Postdoctoral Science Foundation(Grant No.2024M753474)+3 种基金National Natural Science Foundation of China(Grant No.72404267)National Social Science Fund(Grant No.23BGLI88)National Key Research and Development Program of China(Grant No.2017YFC0405805–04)Major program of the National Social Science Fund(Grant No.19ZDA084).
文摘Urbanization develops with the goal of establishing improved and more sustainable habitats for residents.Environmental and social performance must be simultaneously monitored to ascertain whether regions are progressing towards or deviating from the safe and just space(SJS)in urbanization.Despite relevant studies,the absence of indicators that bridge ecological preservation and human well-beings renders dual monitoring challenging.This study bridged the gap by exploring the interactions between urbanization,ecosystem services(ESs),and basic water,energy,and food(WEF)needs within the SJS framework across China and its provinces.By quantifying the minimum and actual demands for freshwater withdrawal,carbon emissions,phosphorus emissions,and land use,as well as the supply of ESs into unified biophysical indicators,we found that:(1)China can meet the basic WEF needs for all from 2000 to 2020,but only water and land provisioning ESs can operate within the SJS.Carbon emissions surpassed the sequestration capacity in 2010,while phosphorus purification ES has consistently been unsafe.(2)The SJS performance in terms of ecological and social fulfilment exhibited scale differences and undergone changes with urbanization.Overall,no province in China can consistently operate within all SJSs.(3)In the process of urbanization,improvements in ecological protection and production practices in most provinces expanded the size of SJS,but the continuous increase in total demand failed to steer regions toward safer spaces.Our framework emphasized the common but differentiated pathways that regions at varying stages of urbanization navigate to achieve safety and justice.It also provides an applicable solution for regions aiming to pursue urban growth while maintaining ecological conservation and social justice,ultimately achieving sustainable development.
文摘Objective:To explore the application effect of bundle management in the safe nursing of patients with autoimmune encephalitis.Methods:Seventy-five patients with autoimmune encephalitis who met the inclusion criteria in our hospital from January 2024 to June 2024 were randomly divided into two groups:an observation group of 39 patients and a control group of 36 patients.The control group received routine nursing care,while the observation group implemented a bundle management strategy based on routine nursing care.Safety nursing outcomes,clinical symptom improvement time,hospital stay,and neurologic function recovery were observed in both groups.Results:The incidence of adverse events in the observation group was 12.82%,significantly lower than the 33.33%in the control group,with a statistically significant difference(P<0.05).There was no statistically significant difference in restraint usage and ICU transfer rates between the two groups(P>0.05).The clinical symptom improvement time,hospital stay,and neurologic function recovery in the observation group were significantly better than those in the control group,with a statistically significant difference(P<0.05).Conclusion:Through the bundle management model,effective connections can be ensured in various aspects of treatment and rehabilitation for patients with autoimmune encephalitis,providing patients with comprehensive and multi-level nursing services and improving their overall satisfaction and treatment effectiveness.
文摘Objective:Nurses must follow safe injection practices to prevent healthcare-associated infections(HAIs).This study aimed to identify the risk factors for safe injection practice among nurses in general hospitals.Methods:This cross-sectional study included 215 nurses employed in Korean general hospitals.Data were collected from September 22 to October 9,2023.Multiple linear regression analysis was performed using SPSS Statistics 27.0.Results:The regression analysis revealed that a higher level of patient safety priority in the patient safety culture perception,increased knowledge of safe injection practices,and fewer working hours per week were associated with improved performance of safe injection practices among general hospital nurses.Conclusions:To enhance the performance of general hospital nurses in safe injection practice,it is necessary to establish a patient safety culture so that nurses recognize patient safety as a top priority.Additionally,an effective educational program is needed to increase the practical knowledge of safe injection practices,along with a supportive working environment that ensures appropriate working hours to prevent patient safety incidents.
基金supported by the National Natural Science Foundation of China(Grant No.42101296)the Natural Science Foundation of Chongqing(Grant No.CSTB2023NSCQ-MSX0041)Chongqing Municipal Training Program of Innovation and Entrepreneurship Project(Grants No.S202410635155 and X202410635116)。
文摘Safe and just operating spaces(SJOS)are influenced by complex cross-scale interactions and cascading effects spanning global,regional,and local landscape scales.However,existing SJOS research has often focused on single-scale assessments,overlooking the impacts of multiscale interactions and within-region heterogeneity on urban SJOS.To address this gap,we developed a cross-scale framework for assessing urban SJOS,explicitly incorporating top-down influences from upper-level constraints and bottom-up effects from lower-level heterogeneity.This approach was applied to China's five major metropolises to examine the states and cross-scale dynamics influencing urban SJOS between 1990 and 2020.Our findings reveal that the SJOS of China's metropolises were primarily influenced by factors at national and local landscape scales,with weaker influences from the global and continental scales.A persistent trade-off between social justice and environmental safety was identified across spatiotemporal scales.For instance,Chongqing in southwestern China lagged behind the eastern four metropolises in social performance but exhibited stronger environmental safety due to its extensive natural landscapes,which mitigated the anthropogenic impacts of urban centers.Regional issues,such as the overshoot of PM_(2.5)and ecological footprints(EF),were primarily driven by the bottom-up accumulation of localized pressures,while the overshoot of CO_(2)was attributed to national policy constraints and the universal exceedance of safe thresholds across scales.Addressing urban sustainability requires avoiding adverse cascading effects from other levels by emphasizing landscape heterogeneity within metropolises and fostering coordinated collaboration across scales,particularly at the regional landscape and national levels.
文摘Semi-supervised clustering techniques attempt to improve clustering accuracy by utilizing a limited number of labeled data for guidance.This method effectively integrates prior knowledge using pre-labeled data.While semi-supervised fuzzy clustering(SSFC)methods leverage limited labeled data to enhance accuracy,they remain highly susceptible to inappropriate or mislabeled prior knowledge,especially in noisy or overlapping datasets where cluster boundaries are ambiguous.To enhance the effectiveness of clustering algorithms,it is essential to leverage labeled data while ensuring the safety of the previous knowledge.Existing solutions,such as the Trusted Safe Semi-Supervised Fuzzy Clustering Method(TS3FCM),struggle with random centroid initialization,fixed neighbor radius formulas,and handling outliers or noise at cluster overlaps.A new framework called Active Safe Semi-Supervised Fuzzy Clustering with Pairwise Constraints Based on Cluster Boundary(AS3FCPC)is proposed in this paper to deal with these problems.It does this by combining pairwise constraints and active learning.AS3FCPC uses active learning to query only the most informative data instances close to the cluster boundaries.It also uses pairwise constraints to enforce the cluster structure,which makes the system more accurate and robust.Extensive test results on diverse datasets,including challenging noisy and overlapping scenarios,demonstrate that AS3FCPC consistently achieves superior performance compared to state-of-the-art methods like TS3FCM and other baselines,especially when the data is noisy and overlaps.This significant improvement underscores AS3FCPC’s potential for reliable and accurate semisupervised fuzzy clustering in complex,real-world applications,particularly by effectively managing mislabeled data and ambiguous cluster boundaries.
文摘Investing in cryptocurrencies is progressively becoming a norm;however,these assets are excessively volatile and often decrease or increase in value instantly.Thus,rational investors holding cryptocurrencies for extended periods firmly search for assets that can diversify their risk,preferably with assets other than cryptocurrencies.In this study,we consider the two most studied cryptocurrencies with the highest capitalization and trading volume/value,namely Bitcoin and Ethereum.Specifically,we examine whether high-performing leading US tech stocks(Facebook,Amazon,Apple,Netflix,Google[FAANG])can provide any diversification benefits to cryptocurrency investors.To do so,we employ dynamic conditional correlation(DCC),asymmetric DCC,time-varying parameter vector autoregression-based connectedness measures,dynamic correlation-based hedge and safe-haven regression analyses,portfolio optimization and hedging strategies,time-and frequency-based wavelet coherence,and high-frequency 10-min intraday data from January 1,2018 to January 31,2023.We find that FAANG stocks can be considered(at least weak)safe havens for Bitcoin and Ethereum during the sample period.Our subperiod analyses reveal that the safehaven role of FAANG stocks,specifically for Bitcoin,has noticeably increased.While the safe-haven property of Facebook is the most promising,for Netflix it is blurred between a weak–safe-haven and a hedge.Our findings may help investors,policymakers,and academicians to invest in cryptocurrencies,formulate relevant investment guidelines,and extend the literature on cryptocurrencies,respectively.
文摘IN the Shanghai Jewish Refugees Museum,a beautiful handbag is waiting for its owner in a display cabinet.The handbag belongs to a Jewish couple.When they sought refuge in Shanghai during World War II,they pawned the handbag to Jin Wenzhen’s grandfather in exchange for their child’s medical expenses.He lent the couple the cash equivalent of one month’s revenue from his rice shop,but then never saw them again.
文摘Against the backdrop of the global push for environmental protection and the reduction of plastic pollution,the research and development of alternatives to daily disposable plastic products such as straws have become a hot topic in the environmental protection field.Traditional plastic straws are difficult to degrade,imposing a severe burden on the environment.Meanwhile,existing alternatives like paper straws and PLA(polylactic acid)straws also have numerous drawbacks.
文摘Low visibility conditions,particularly those caused by fog,significantly affect road safety and reduce drivers’ability to see ahead clearly.The conventional approaches used to address this problem primarily rely on instrument-based and fixed-threshold-based theoretical frameworks,which face challenges in adaptability and demonstrate lower performance under varying environmental conditions.To overcome these challenges,we propose a real-time visibility estimation model that leverages roadside CCTV cameras to monitor and identify visibility levels under different weather conditions.The proposedmethod begins by identifying specific regions of interest(ROI)in the CCTVimages and focuses on extracting specific features such as the number of lines and contours detected within these regions.These features are then provided as an input to the proposed hierarchical clusteringmodel,which classifies them into different visibility levels without the need for predefined rules and threshold values.In the proposed approach,we used two different distance similaritymetrics,namely dynamic time warping(DTW)and Euclidean distance,alongside the proposed hierarchical clustering model and noted its performance in terms of numerous evaluation measures.The proposed model achieved an average accuracy of 97.81%,precision of 91.31%,recall of 91.25%,and F1-score of 91.27% using theDTWdistancemetric.We also conducted experiments for other deep learning(DL)-based models used in the literature and compared their performances with the proposed model.The experimental results demonstrate that the proposedmodel ismore adaptable and consistent compared to themethods used in the literature.The proposedmethod provides drivers real-time and accurate visibility information and enhances road safety during low visibility conditions.
文摘With the civilization and modernization of human society,occupational health has emerged as a fundamental goal of social justice,as highlighted in the United Nations'Sustainable Development Goals(SDGs)since 2016.Specifically,"SDG Goal 1:No Poverty","SDG 3:Good Health and Well-being",and"SDG 8:Decent Work and Economic Growth",are interconnected with other SDGs to support the pursuit of occupational health.
