Promoting occupational safety and health in Hong Kong,Special Administrative Region of China is an important and ongoing mission. As the major organization with statutory responsibilities,the Occupational Safety and H...Promoting occupational safety and health in Hong Kong,Special Administrative Region of China is an important and ongoing mission. As the major organization with statutory responsibilities,the Occupational Safety and Health Council understand the importance to strengthen and cultivate our safety culture. It is widely believed that numbers of occupational related diseases and injuries could be prevented with the improvement of the awareness and attitudes of the employees and the public. Therefore,a comprehensive and in-depth study to monitor the occupational health and safety level and status of the community and working population is needed. Objectives: Our Council has developed the Occupational Safety Culture Index ( OSCI) to measure the current level of community and workplace safety and health awareness,knowledge and attitude. Benchmarking measures of the key safety performance indicators are to be derived thereof. Methods: A territory-wide random telephone survey was conducted to assess the community and employees'awareness,attitude and knowledge in 2008. A structured questionnaire was designed with the content validity and reliability assessed before the survey administration. A series of quality control approaches were also applied to assure the quality of the fieldwork and the reliability of the data. Results: 1,531 eligible participants'data were collected and computed into 2 types of composite indices,Occupational Safety Culture Index ( Community) ( OSCIC) and Occupational Safety Culture Index (Workplace) (OSCIW) . With the maximum score of index at 100,the overall score of OSCIC is 66. 9 and the OSCIW is 61. 3 in Hong Kong. Achievements: OSCI served as an effective management tool to measure the safety culture in Hong Kong. With a representative sample and high quality study control and validated assessment approaches,the OSCI and the sub-indices are reliable indicators to assess the effectiveness of safety culture enhancement strategy and the OSH intervention measures.展开更多
Of the 700,000 people in the United States who experience a new or recurrent stroke each year,more than 500,000 survive(American Stroke Association,2007)[1]. Occupational therapy practitioners are critical rehabilitat...Of the 700,000 people in the United States who experience a new or recurrent stroke each year,more than 500,000 survive(American Stroke Association,2007)[1]. Occupational therapy practitioners are critical rehabilitation professionals for stroke survivors.展开更多
An epidemiologic health survey was carried out among 314 workers in one of grain elevators in Shenyang.A medical and occupational questionnaire was administered by trained interviewers. Spirometry was performed on sit...An epidemiologic health survey was carried out among 314 workers in one of grain elevators in Shenyang.A medical and occupational questionnaire was administered by trained interviewers. Spirometry was performed on site. 61.47% of the grain workers complained of one or more respiratory symptoms during or after exposure to airborne grain dust.The prevalence of various symptoms was significantly higher among grain workers than control subjects. 15.6% of the grain workers had episodes of grain fever. The mean values of V<sub>max75</sub>, V<sub>max50</sub>, and V<sub>max25</sub> was significantly lower for grain workers than control subjects, suggesting that the group of grain workers had evidence of small airway dysfunction. Pulmonary function abnormalities were associated with increased duration of employment in the grain elevator,smoking was also associated with deterioration of respiratory function.展开更多
Driving involves long hours of physical work within c onfined compartment. Taxi drivers usually work with prolonged working hours, add itional stress may likely be induced on particular body limbs. Occupational heal t...Driving involves long hours of physical work within c onfined compartment. Taxi drivers usually work with prolonged working hours, add itional stress may likely be induced on particular body limbs. Occupational heal th may occur and working efficiency may potentially be affected resulting fr om fatigues, pains or diseases. These problems, however, could be remedied if mo re attention is paid on seating design, the workplace and driving postures adopt ed. Ergonomics design can provide better understanding of those concerned areas. A study was conducted to analyse occupational and health problems related to ta xi drivers. Through ergonomic evaluation of driver’s compartment, the authors m ake recommendations to improve health and safety aspects. Besides, the experienc e of gained from this study using ergonomic design can be extended to other occu pation or products.展开更多
Recent advances in on-board radar and missile capabilities,combined with individual payload limitations,have led to increased interest in the use of unmanned combat aerial vehicles(UCAVs)for cooperative occupation dur...Recent advances in on-board radar and missile capabilities,combined with individual payload limitations,have led to increased interest in the use of unmanned combat aerial vehicles(UCAVs)for cooperative occupation during beyond-visual-range(BVR)air combat.However,prior research on occupational decision-making in BVR air combat has mostly been limited to one-on-one scenarios.As such,this study presents a practical cooperative occupation decision-making methodology for use with multiple UCAVs.The weapon engagement zone(WEZ)and combat geometry were first used to develop an advantage function for situational assessment of one-on-one engagement.An encircling advantage function was then designed to represent the cooperation of UCAVs,thereby establishing a cooperative occupation model.The corresponding objective function was derived from the one-on-one engagement advantage function and the encircling advantage function.The resulting model exhibited similarities to a mixed-integer nonlinear programming(MINLP)problem.As such,an improved discrete particle swarm optimization(DPSO)algorithm was used to identify a solution.The occupation process was then converted into a formation switching task as part of the cooperative occupation model.A series of simulations were conducted to verify occupational solutions in varying situations,including two-on-two engagement.Simulated results showed these solutions varied with initial conditions and weighting coefficients.This occupation process,based on formation switching,effectively demonstrates the viability of the proposed technique.These cooperative occupation results could provide a theoretical framework for subsequent research in cooperative BVR air combat.展开更多
Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different...Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different traffic conditions were presented, based on the relationship between the three basic traffic flow parameters, speed, traffic flow and density. Secondly, the times at which the stopping and starting waves approach a loop detector were confirmed using the traffic wave models modified by a kinematic equation. Then, the threshold of occupancy, which characterizes the appearance of spillovers, was determined by the premise that the stopping and starting waves had the same speed. At last, the accuracy and usability of the new method were verified by VISSIM simulation, using the ratio of misjudgment as the evaluation index. The results show that the ratio of misjudgment of the new method is about 11.36% compared to 17.65% of the previous method.展开更多
The emergence of improvised explosive devices (IED) significantly extended the spectrum of possiblethreat mechanisms to military vehicles and their occupants. Especially buried high explosive (HE)charges lead to new a...The emergence of improvised explosive devices (IED) significantly extended the spectrum of possiblethreat mechanisms to military vehicles and their occupants. Especially buried high explosive (HE)charges lead to new and originally not investigated loading conditions during their detonation. It is theinteraction of the embedding geomaterial with the detonation products that leads to a strongly increasedglobal impulse transfer on the vehicle with following high accelerations on the vehicle occupant. Thispaper presents a comprehensive approach for the analysis of occupant loading. In a first step, we presentthe so called ring technology which allows the experimental determination of the locally resolvedspecific impulse distribution on a vehicle floor due to buried charge detonation. A complementarymethod is the use of scaled model vehicles that allows the determination of global vehicle loading parameterssuch as jump height or vehicle accelerations. Both techniques were used to study the influenceof burial conditions as burial depth, embedding material or water content on the impulse transfer ontothe vehicle. These experimental data are used to validate material models for the embedding sand orgravel materials. This validated material description is the basis for numerical simulation models used inthe assessment of occupant safety. In the last step, we present a simulation model for a generic militaryvehicle including a Hybrid III occupant dummy that is used for the determination of biomechanicaloccupant exposure levels. Typical occupant loadings are evaluated and correlated with burial conditionsas HE mass and global momentum transfer.展开更多
The formation control of multiple unmanned aerial vehicles(multi-UAVs)has always been a research hotspot.Based on the straight line trajectory,a multi-UAVs target point assignment algorithm based on the assignment pro...The formation control of multiple unmanned aerial vehicles(multi-UAVs)has always been a research hotspot.Based on the straight line trajectory,a multi-UAVs target point assignment algorithm based on the assignment probability is proposed to achieve the shortest overall formation path of multi-UAVs with low complexity and reduce the energy consumption.In order to avoid the collision between UAVs in the formation process,the concept of safety ball is introduced,and the collision detection based on continuous motion of two time slots and the lane occupation detection after motion is proposed to avoid collision between UAVs.Based on the idea of game theory,a method of UAV motion form setting based on the maximization of interests is proposed,including the maximization of self-interest and the maximization of formation interest is proposed,so that multi-UAVs can complete the formation task quickly and reasonably with the linear trajectory assigned in advance.Finally,through simulation verification,the multi-UAVs target assignment algorithm based on the assignment probability proposed in this paper can effectively reduce the total path length,and the UAV motion selection method based on the maximization interests can effectively complete the task formation.展开更多
Saponite has been widely used in a number of industrial fields because of the higher surface acidity and thermal stability when compared with other clay minerals (Alexander and Dubois, 2000; Casagrande et al., 2005). ...Saponite has been widely used in a number of industrial fields because of the higher surface acidity and thermal stability when compared with other clay minerals (Alexander and Dubois, 2000; Casagrande et al., 2005). Due to its limited natural resource, synthesis of saponite has attracted much attention during the last two decades (Vogels et al., 2005; Bisio et al., 2008). The main aim of this study is to investigate occupancy of Al ions and its effect on the structure of synthetic saponites.展开更多
Germany became a single country at midnight, October 2, ending 45 years of division. unification came a month after the four World War Ⅱ allies agreed in Moscow to end their occupation rights and
At 02:30 am Baghdad time on January 17, the U. S. and allied forces carried out 1000 sorties air and 100 ship-launcnea cruise missile strikes, blasting Iraqi targets to free Kuwait from Iraqi occupation. The attack be...At 02:30 am Baghdad time on January 17, the U. S. and allied forces carried out 1000 sorties air and 100 ship-launcnea cruise missile strikes, blasting Iraqi targets to free Kuwait from Iraqi occupation. The attack began less than 19 hours after the expiration of the UN-mandated deadline. From the following day to the end of the month, the U.S.-led allied air forces continued massive bombing&against targets in Iraq and occupied Kuwait. From展开更多
文摘Promoting occupational safety and health in Hong Kong,Special Administrative Region of China is an important and ongoing mission. As the major organization with statutory responsibilities,the Occupational Safety and Health Council understand the importance to strengthen and cultivate our safety culture. It is widely believed that numbers of occupational related diseases and injuries could be prevented with the improvement of the awareness and attitudes of the employees and the public. Therefore,a comprehensive and in-depth study to monitor the occupational health and safety level and status of the community and working population is needed. Objectives: Our Council has developed the Occupational Safety Culture Index ( OSCI) to measure the current level of community and workplace safety and health awareness,knowledge and attitude. Benchmarking measures of the key safety performance indicators are to be derived thereof. Methods: A territory-wide random telephone survey was conducted to assess the community and employees'awareness,attitude and knowledge in 2008. A structured questionnaire was designed with the content validity and reliability assessed before the survey administration. A series of quality control approaches were also applied to assure the quality of the fieldwork and the reliability of the data. Results: 1,531 eligible participants'data were collected and computed into 2 types of composite indices,Occupational Safety Culture Index ( Community) ( OSCIC) and Occupational Safety Culture Index (Workplace) (OSCIW) . With the maximum score of index at 100,the overall score of OSCIC is 66. 9 and the OSCIW is 61. 3 in Hong Kong. Achievements: OSCI served as an effective management tool to measure the safety culture in Hong Kong. With a representative sample and high quality study control and validated assessment approaches,the OSCI and the sub-indices are reliable indicators to assess the effectiveness of safety culture enhancement strategy and the OSH intervention measures.
文摘Of the 700,000 people in the United States who experience a new or recurrent stroke each year,more than 500,000 survive(American Stroke Association,2007)[1]. Occupational therapy practitioners are critical rehabilitation professionals for stroke survivors.
文摘An epidemiologic health survey was carried out among 314 workers in one of grain elevators in Shenyang.A medical and occupational questionnaire was administered by trained interviewers. Spirometry was performed on site. 61.47% of the grain workers complained of one or more respiratory symptoms during or after exposure to airborne grain dust.The prevalence of various symptoms was significantly higher among grain workers than control subjects. 15.6% of the grain workers had episodes of grain fever. The mean values of V<sub>max75</sub>, V<sub>max50</sub>, and V<sub>max25</sub> was significantly lower for grain workers than control subjects, suggesting that the group of grain workers had evidence of small airway dysfunction. Pulmonary function abnormalities were associated with increased duration of employment in the grain elevator,smoking was also associated with deterioration of respiratory function.
文摘Driving involves long hours of physical work within c onfined compartment. Taxi drivers usually work with prolonged working hours, add itional stress may likely be induced on particular body limbs. Occupational heal th may occur and working efficiency may potentially be affected resulting fr om fatigues, pains or diseases. These problems, however, could be remedied if mo re attention is paid on seating design, the workplace and driving postures adopt ed. Ergonomics design can provide better understanding of those concerned areas. A study was conducted to analyse occupational and health problems related to ta xi drivers. Through ergonomic evaluation of driver’s compartment, the authors m ake recommendations to improve health and safety aspects. Besides, the experienc e of gained from this study using ergonomic design can be extended to other occu pation or products.
基金supported by the National Natural Science Foundation of China(No.61573286)the Aeronautical Science Foundation of China(No.20180753006)+2 种基金the Fundamental Research Funds for the Central Universities(3102019ZDHKY07)the Natural Science Foundation of Shaanxi Province(2020JQ-218)the Shaanxi Province Key Laboratory of Flight Control and Simulation Technology。
文摘Recent advances in on-board radar and missile capabilities,combined with individual payload limitations,have led to increased interest in the use of unmanned combat aerial vehicles(UCAVs)for cooperative occupation during beyond-visual-range(BVR)air combat.However,prior research on occupational decision-making in BVR air combat has mostly been limited to one-on-one scenarios.As such,this study presents a practical cooperative occupation decision-making methodology for use with multiple UCAVs.The weapon engagement zone(WEZ)and combat geometry were first used to develop an advantage function for situational assessment of one-on-one engagement.An encircling advantage function was then designed to represent the cooperation of UCAVs,thereby establishing a cooperative occupation model.The corresponding objective function was derived from the one-on-one engagement advantage function and the encircling advantage function.The resulting model exhibited similarities to a mixed-integer nonlinear programming(MINLP)problem.As such,an improved discrete particle swarm optimization(DPSO)algorithm was used to identify a solution.The occupation process was then converted into a formation switching task as part of the cooperative occupation model.A series of simulations were conducted to verify occupational solutions in varying situations,including two-on-two engagement.Simulated results showed these solutions varied with initial conditions and weighting coefficients.This occupation process,based on formation switching,effectively demonstrates the viability of the proposed technique.These cooperative occupation results could provide a theoretical framework for subsequent research in cooperative BVR air combat.
基金Project(2011AA110304) supported by the National High Technology Research and Development Program of China
文摘Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different traffic conditions were presented, based on the relationship between the three basic traffic flow parameters, speed, traffic flow and density. Secondly, the times at which the stopping and starting waves approach a loop detector were confirmed using the traffic wave models modified by a kinematic equation. Then, the threshold of occupancy, which characterizes the appearance of spillovers, was determined by the premise that the stopping and starting waves had the same speed. At last, the accuracy and usability of the new method were verified by VISSIM simulation, using the ratio of misjudgment as the evaluation index. The results show that the ratio of misjudgment of the new method is about 11.36% compared to 17.65% of the previous method.
基金the German test range WTD-91 GF-440 in Meppen for funding this work
文摘The emergence of improvised explosive devices (IED) significantly extended the spectrum of possiblethreat mechanisms to military vehicles and their occupants. Especially buried high explosive (HE)charges lead to new and originally not investigated loading conditions during their detonation. It is theinteraction of the embedding geomaterial with the detonation products that leads to a strongly increasedglobal impulse transfer on the vehicle with following high accelerations on the vehicle occupant. Thispaper presents a comprehensive approach for the analysis of occupant loading. In a first step, we presentthe so called ring technology which allows the experimental determination of the locally resolvedspecific impulse distribution on a vehicle floor due to buried charge detonation. A complementarymethod is the use of scaled model vehicles that allows the determination of global vehicle loading parameterssuch as jump height or vehicle accelerations. Both techniques were used to study the influenceof burial conditions as burial depth, embedding material or water content on the impulse transfer ontothe vehicle. These experimental data are used to validate material models for the embedding sand orgravel materials. This validated material description is the basis for numerical simulation models used inthe assessment of occupant safety. In the last step, we present a simulation model for a generic militaryvehicle including a Hybrid III occupant dummy that is used for the determination of biomechanicaloccupant exposure levels. Typical occupant loadings are evaluated and correlated with burial conditionsas HE mass and global momentum transfer.
基金supported by the Basic Scientific Research Business Expenses of Central Universities(3072022QBZ0806)。
文摘The formation control of multiple unmanned aerial vehicles(multi-UAVs)has always been a research hotspot.Based on the straight line trajectory,a multi-UAVs target point assignment algorithm based on the assignment probability is proposed to achieve the shortest overall formation path of multi-UAVs with low complexity and reduce the energy consumption.In order to avoid the collision between UAVs in the formation process,the concept of safety ball is introduced,and the collision detection based on continuous motion of two time slots and the lane occupation detection after motion is proposed to avoid collision between UAVs.Based on the idea of game theory,a method of UAV motion form setting based on the maximization of interests is proposed,including the maximization of self-interest and the maximization of formation interest is proposed,so that multi-UAVs can complete the formation task quickly and reasonably with the linear trajectory assigned in advance.Finally,through simulation verification,the multi-UAVs target assignment algorithm based on the assignment probability proposed in this paper can effectively reduce the total path length,and the UAV motion selection method based on the maximization interests can effectively complete the task formation.
文摘Saponite has been widely used in a number of industrial fields because of the higher surface acidity and thermal stability when compared with other clay minerals (Alexander and Dubois, 2000; Casagrande et al., 2005). Due to its limited natural resource, synthesis of saponite has attracted much attention during the last two decades (Vogels et al., 2005; Bisio et al., 2008). The main aim of this study is to investigate occupancy of Al ions and its effect on the structure of synthetic saponites.
文摘Germany became a single country at midnight, October 2, ending 45 years of division. unification came a month after the four World War Ⅱ allies agreed in Moscow to end their occupation rights and
文摘At 02:30 am Baghdad time on January 17, the U. S. and allied forces carried out 1000 sorties air and 100 ship-launcnea cruise missile strikes, blasting Iraqi targets to free Kuwait from Iraqi occupation. The attack began less than 19 hours after the expiration of the UN-mandated deadline. From the following day to the end of the month, the U.S.-led allied air forces continued massive bombing&against targets in Iraq and occupied Kuwait. From
