Consider two dependent renewal risk models with constant interest rate. By using some methods in the risk theory, uniform asymptotics for finite-time ruin probability is derived in a non-compound risk model, where cla...Consider two dependent renewal risk models with constant interest rate. By using some methods in the risk theory, uniform asymptotics for finite-time ruin probability is derived in a non-compound risk model, where claim sizes are upper tail asymptotically independent random variables with dominatedly varying tails, claim inter-arrival times follow the widely lower orthant dependent structure, and the total amount of premiums is a nonnegative stochastic process. Based on the obtained result, using the method of analysis for the tail probability of random sums, a similar result in a more complex and reasonable compound risk model is also obtained, where individual claim sizes are specialized to be extended negatively dependent and accident inter-arrival times are still widely lower orthant dependent, and both the claim sizes and the claim number have dominatedly varying tails.展开更多
A set of model is established to optimize BSW Company’s component stock. By analyzing the company’s current part stock condition in terms of the occupation of capitals in the precondition of continuous production, i...A set of model is established to optimize BSW Company’s component stock. By analyzing the company’s current part stock condition in terms of the occupation of capitals in the precondition of continuous production, it describes how to control the purchase parameters of import parts. The model describes how to adjust slightly product output sequence and how to control the components’ purchase parameters: purchasing risk time and purchase order quantity. Then simulation is developed to illustrate the model.展开更多
This paper presents findings from an investigation of the large-scale construction solid waste （CSW） landslide that occurred at a landfill at Shenzhen, Guangdong, China, on December 20, 2015, and which killed 77 peo...This paper presents findings from an investigation of the large-scale construction solid waste （CSW） landslide that occurred at a landfill at Shenzhen, Guangdong, China, on December 20, 2015, and which killed 77 people and destroyed 33 houses. The landslide involved 2.73 - 106 m3 of CSW and affected an area about 1100 m in length and 630 m in maximum width, making it the largest landfill landslide in the world. The investigation of this disaster used a combination of unmanned aerial vehicle surveillance and multistage remote-sensing images to reveal the increasing volume of waste in the landfill and the shifting shape of the landfill slope for nearly two years before the landslide took place, beginning with the creation of the CSW landfill in March, 2014, that resulted in the uncertain conditions of the landfill＇s boundaries and the unstable state of the hydrologic performance. As a result, applying conventional stability analysis methods used for natural landslides to this case would be difficult. In order to analyze this disaster, we took a multistage modeling technique to analyze the varied characteristics of the land- fill slope＇s structure at various stages of CSW dumping and used the non-steady flow theory to explain the groundwater seepage problem. The investigation showed that the landfill could be divided into two units based on the moisture in the land： （1） a front uint, consisted of the landfill slope, which had low water content; and （2） a rear unit, consisted of fresh waste, which had a high water content. This struc- ture caused two effects-surface-water infiltration and consolidation seepage that triggered the landslide in the landfill. Surface-water infiltration induced a gradual increase in pore water pressure head, or piezometric head, in the front slope because the infiltrating position rose as the volume of waste placement increased. Consolidation seepage led to higher excess pore water pressures as the loading of waste increased. We also investigated the post-failure soil dynamics parameters of the landslide deposit using cone penetration, triaxial, and ring-shear tests in order to simulate the characteristics of a flowing slide with a long run-out due to the liquefaction effect. Finally, we conclude the paper with lessons from the tens of catastrophic landslides of municipal solid waste around the world and discuss how to better manage the geotechnical risks of urbanization.展开更多
Background Obstructive sleep apnea （OSA） is a common disease in patients with acute coronary syndrome （ACS） and associated with an increased risk of fatal and nonfatal cardiovascular events. However, most patients...Background Obstructive sleep apnea （OSA） is a common disease in patients with acute coronary syndrome （ACS） and associated with an increased risk of fatal and nonfatal cardiovascular events. However, most patients in previous study were treated with bare metal stents and the sample sizes were relatively low. The goal of this study was to evaluate the influence of OSA on the severity and prognosis of patients admitted for ACS. Methods In this prospective cohort study, we enrolled patients with ACS who were hospitalized for coronary angiogram/percutaneous coronary intervention and undergone polysomnography. We divided the patients into two groups： moderate to severe OSA group [apnea-hypopnea index （AHI） 〉 15 events/h] and control group （AHI ≤ 15 events/h）. They were followed up for up 32 months. Then, we compared the ACS severity and long-term major adverse cardiovascular events （MACE） in patients with different severity of OSA. Results Five hundred and twenty nine patients were included in the final analysis, with 76% of them being men and an average age of 59 ＋ 10 years. The overall mean AHI is 29 ± 19 events/h, 70.5% of them （373/529） being with moderate to severe OSA and 29.5% （156/529） assign into control group. Compared with controls, patients with moderate or severe OSA exhibited a higher prevalence of hypertension as well as higher body mass index, SYNTAX score, Epworth score and length of hospitalization. With a median follow-up duration of 30 months, accumulative rate of MACE was also higher in patients with moderate or severe OSA than that in the control group （8.6% vs. 3.2%, P = 0.028）. After adjusting for baseline confounders by cox regression model, moderate to severe OSA was an independent risk factor of long-term MACE （P = 0.047, HR = 1.618, 95% CI： 1.069-3.869）. Conclusions The results of this study demonstrate that moderate or severe OSA is correlated with disease severity and associated with worse long-term prognosis in ACS patients. The results raising the possibility that early diagnose and interventions of OSA could improve long-term outcomes in ACS patients.展开更多
Exploitation of coal seams in the Upper Silesian Coal Basin is conducted in complex and difficult conditions. These difficulties are connected with the occurrence of many natural mining hazards and limitations resulti...Exploitation of coal seams in the Upper Silesian Coal Basin is conducted in complex and difficult conditions. These difficulties are connected with the occurrence of many natural mining hazards and limitations resulting from the existing in this area surface infrastructure. One of the most important problems of Polish mining is the rock burst hazard and reliable evaluation of its condition. During long-years’ mining practice in Poland a comprehensive system of evaluation and control of this hazard was developed. In the paper the main aspects of rock burst hazard state evaluation will be presented, comprising: 1) rock mass inclination for rock bursts, i.e., rock strength properties investigation, comprehensive parametric evaluation of rock mass inclination for rock bursts, prognosis of seismic events induced by mining operations, methods of computer-aided modelling of stress and rock mass deformation parameters distribution, strategic rock mass classification under rock burst degrees; 2) immediate seismic and rock burst hazard state evaluation, i.e., low diameter test drilling method, seismologic and seismoacoustic method, comprehensive method of rock burst hazard state evaluation, non-standard methods of evaluation; 3) legal aspects of rock burst hazard state evaluation. Selected elements of the hazard state evaluation system are illustrated with specific practical examples of their application.展开更多
The new type of risk management is process management. First, the hazardsources are identified before coal mine accidents occur, and then the pre-control measureand information monitoring method based on classifying t...The new type of risk management is process management. First, the hazardsources are identified before coal mine accidents occur, and then the pre-control measureand information monitoring method based on classifying the hidden hazard sources aregiven. Lastly, the risk pre-alarm and risk control method are confirmed, the managementstandard and management measure are used to eliminate the hidden hazard sources. Inthis study, an evaluation system is built to evaluate the result of risk management.展开更多
In recent years, the academic and practical circles have paid so much attention to similar financial models because they generated a miracle in GOME （Gome Electrical Appliances Holding Limited） and SUNING （Suning A...In recent years, the academic and practical circles have paid so much attention to similar financial models because they generated a miracle in GOME （Gome Electrical Appliances Holding Limited） and SUNING （Suning Appliance Co., Ltd.） respectively. But what＇s the influence of such a model on corporate profitability and risk？ Are similar financial models free lunches？ To seek for the answers to the above questions, in this paper, we take Gree （GREE Electric Appliances, Inc. of Zhuhai）, Midea （Guangdong Midea Electric Appliances Co. Ltd. Stores） and GOME for examples to carry out a comprehensive and in depth financial analysis. The conclusions of this paper are： The company with similar financial characteristics has higher profitability and risk level; Only the companies which meet special requirements need or can implement such a model and the identification and control of hidden risk can guarantee its success.展开更多
This paper surnmarizes the historical experiences in venereal disease control in China during the 1950s.Venereal diseases had been all but eliminated in the whole country till 1964. However, along with the implementat...This paper surnmarizes the historical experiences in venereal disease control in China during the 1950s.Venereal diseases had been all but eliminated in the whole country till 1964. However, along with the implementation of open-door policy and economic reform in the 1980s, the social environment was changed to a great extent in this country. Sexually transmitted diseases (STDs) were reintreduced in the Chinese mainland and new foci of infection established themselves in some cities. During the recent 8 years the national STD case-reporting and sentinel surveillance systems have been set up. The results of surveillance show that the annual incidence of STD has been on the increase. The existing factors associated with the increasing incidence of STD mainly are ; population movement , increasing affiuence in a part of population,the availability of multiple sexual partners (including the prostitution)and asymptomatic STD increased.Finally, the strategies for STD control are discussed in detail.展开更多
Motion state of ship out of control in bridge area was analyzed.Motion procedure after losing control was divided into two steps.One is drift step within stopping period.The other is drift step without inertia,which i...Motion state of ship out of control in bridge area was analyzed.Motion procedure after losing control was divided into two steps.One is drift step within stopping period.The other is drift step without inertia,which is induced by wind and current.Mathematical model for motion of ship out of control,considering wind-induced drift,current-induced drift,stopping ability,etc.,was established.Dangerous collision areas for main pier and auxiliary piers were analyzed according to different calculation conditions.展开更多
Engineering project management refers to the management through the whole process of engineering construction, including quality, time project time limit, safety, cost, environmental protection, and innovation, etc. T...Engineering project management refers to the management through the whole process of engineering construction, including quality, time project time limit, safety, cost, environmental protection, and innovation, etc. The most important thing for construction enterprises to improve market competitiveness is to reduce enterprise costs by decreasing resource consumption in the construction, and control the consumptions within the project budget.展开更多
Overbuilding, i.e. capping or decking, of roads assigned for the transportation of dangerous goods in major cities is being considered more often in many countries including Sweden. This type of facility introduces a ...Overbuilding, i.e. capping or decking, of roads assigned for the transportation of dangerous goods in major cities is being considered more often in many countries including Sweden. This type of facility introduces a number of risks and challenges related to rare events, such as dangerous goods accidents in tunnels, with a potential to cause substantial damage, e.g. collapse of buildings on the over site development. Many argue that the major problem associated with risk evaluation of such risks is the lack of commonly agreed acceptance criteria and regulations. Approaching the problem from a scientific perspective suggests that the root cause of this problem has not been adequately identified. However, there are strong indications that it is because the nature of the risk is not adequately addressed in risk analysis. In this study, we have structured the problem and propose ways of making progress in the evaluation of risk exposure and risk control. It is concluded that several challenges are inherent in the risk management of decking over routes for the transport of dangerous goods, and that these must be addressed in order to be able to control the risk. One of the complicating factors is that it is practically and economically impossible to construct the overbuilding so that it can withstand the maximum permissible explosion load. The main conclusions of this study are that overbuilding of dangerous goods routes has the potential to lead to catastrophic events, that the transport of dangerous goods in the future is associated with considerable intrinsic uncertainties, and that the possibility of supervising and controlling the transport of goods is limited once the route is in use.展开更多
The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results...The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.展开更多
基金The National Natural Science Foundation of China(No.11001052,11171065,71171046)China Postdoctoral Science Foundation(No.2012M520964)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20131339)the Qing Lan Project of Jiangsu Province
文摘Consider two dependent renewal risk models with constant interest rate. By using some methods in the risk theory, uniform asymptotics for finite-time ruin probability is derived in a non-compound risk model, where claim sizes are upper tail asymptotically independent random variables with dominatedly varying tails, claim inter-arrival times follow the widely lower orthant dependent structure, and the total amount of premiums is a nonnegative stochastic process. Based on the obtained result, using the method of analysis for the tail probability of random sums, a similar result in a more complex and reasonable compound risk model is also obtained, where individual claim sizes are specialized to be extended negatively dependent and accident inter-arrival times are still widely lower orthant dependent, and both the claim sizes and the claim number have dominatedly varying tails.
文摘A set of model is established to optimize BSW Company’s component stock. By analyzing the company’s current part stock condition in terms of the occupation of capitals in the precondition of continuous production, it describes how to control the purchase parameters of import parts. The model describes how to adjust slightly product output sequence and how to control the components’ purchase parameters: purchasing risk time and purchase order quantity. Then simulation is developed to illustrate the model.
文摘This paper presents findings from an investigation of the large-scale construction solid waste （CSW） landslide that occurred at a landfill at Shenzhen, Guangdong, China, on December 20, 2015, and which killed 77 people and destroyed 33 houses. The landslide involved 2.73 - 106 m3 of CSW and affected an area about 1100 m in length and 630 m in maximum width, making it the largest landfill landslide in the world. The investigation of this disaster used a combination of unmanned aerial vehicle surveillance and multistage remote-sensing images to reveal the increasing volume of waste in the landfill and the shifting shape of the landfill slope for nearly two years before the landslide took place, beginning with the creation of the CSW landfill in March, 2014, that resulted in the uncertain conditions of the landfill＇s boundaries and the unstable state of the hydrologic performance. As a result, applying conventional stability analysis methods used for natural landslides to this case would be difficult. In order to analyze this disaster, we took a multistage modeling technique to analyze the varied characteristics of the land- fill slope＇s structure at various stages of CSW dumping and used the non-steady flow theory to explain the groundwater seepage problem. The investigation showed that the landfill could be divided into two units based on the moisture in the land： （1） a front uint, consisted of the landfill slope, which had low water content; and （2） a rear unit, consisted of fresh waste, which had a high water content. This struc- ture caused two effects-surface-water infiltration and consolidation seepage that triggered the landslide in the landfill. Surface-water infiltration induced a gradual increase in pore water pressure head, or piezometric head, in the front slope because the infiltrating position rose as the volume of waste placement increased. Consolidation seepage led to higher excess pore water pressures as the loading of waste increased. We also investigated the post-failure soil dynamics parameters of the landslide deposit using cone penetration, triaxial, and ring-shear tests in order to simulate the characteristics of a flowing slide with a long run-out due to the liquefaction effect. Finally, we conclude the paper with lessons from the tens of catastrophic landslides of municipal solid waste around the world and discuss how to better manage the geotechnical risks of urbanization.
文摘Background Obstructive sleep apnea （OSA） is a common disease in patients with acute coronary syndrome （ACS） and associated with an increased risk of fatal and nonfatal cardiovascular events. However, most patients in previous study were treated with bare metal stents and the sample sizes were relatively low. The goal of this study was to evaluate the influence of OSA on the severity and prognosis of patients admitted for ACS. Methods In this prospective cohort study, we enrolled patients with ACS who were hospitalized for coronary angiogram/percutaneous coronary intervention and undergone polysomnography. We divided the patients into two groups： moderate to severe OSA group [apnea-hypopnea index （AHI） 〉 15 events/h] and control group （AHI ≤ 15 events/h）. They were followed up for up 32 months. Then, we compared the ACS severity and long-term major adverse cardiovascular events （MACE） in patients with different severity of OSA. Results Five hundred and twenty nine patients were included in the final analysis, with 76% of them being men and an average age of 59 ＋ 10 years. The overall mean AHI is 29 ± 19 events/h, 70.5% of them （373/529） being with moderate to severe OSA and 29.5% （156/529） assign into control group. Compared with controls, patients with moderate or severe OSA exhibited a higher prevalence of hypertension as well as higher body mass index, SYNTAX score, Epworth score and length of hospitalization. With a median follow-up duration of 30 months, accumulative rate of MACE was also higher in patients with moderate or severe OSA than that in the control group （8.6% vs. 3.2%, P = 0.028）. After adjusting for baseline confounders by cox regression model, moderate to severe OSA was an independent risk factor of long-term MACE （P = 0.047, HR = 1.618, 95% CI： 1.069-3.869）. Conclusions The results of this study demonstrate that moderate or severe OSA is correlated with disease severity and associated with worse long-term prognosis in ACS patients. The results raising the possibility that early diagnose and interventions of OSA could improve long-term outcomes in ACS patients.
基金Project R0903003 supported by the Research-Development Project of Poland
文摘Exploitation of coal seams in the Upper Silesian Coal Basin is conducted in complex and difficult conditions. These difficulties are connected with the occurrence of many natural mining hazards and limitations resulting from the existing in this area surface infrastructure. One of the most important problems of Polish mining is the rock burst hazard and reliable evaluation of its condition. During long-years’ mining practice in Poland a comprehensive system of evaluation and control of this hazard was developed. In the paper the main aspects of rock burst hazard state evaluation will be presented, comprising: 1) rock mass inclination for rock bursts, i.e., rock strength properties investigation, comprehensive parametric evaluation of rock mass inclination for rock bursts, prognosis of seismic events induced by mining operations, methods of computer-aided modelling of stress and rock mass deformation parameters distribution, strategic rock mass classification under rock burst degrees; 2) immediate seismic and rock burst hazard state evaluation, i.e., low diameter test drilling method, seismologic and seismoacoustic method, comprehensive method of rock burst hazard state evaluation, non-standard methods of evaluation; 3) legal aspects of rock burst hazard state evaluation. Selected elements of the hazard state evaluation system are illustrated with specific practical examples of their application.
基金Supported by the National Natural Science Foundation of China(70533050)the Eleventh Five-year Science & Technology Support Plan of China(2006BAK03B0703)the Ministry of Education Humanities and Social Science (08JA630083)
文摘The new type of risk management is process management. First, the hazardsources are identified before coal mine accidents occur, and then the pre-control measureand information monitoring method based on classifying the hidden hazard sources aregiven. Lastly, the risk pre-alarm and risk control method are confirmed, the managementstandard and management measure are used to eliminate the hidden hazard sources. Inthis study, an evaluation system is built to evaluate the result of risk management.
文摘In recent years, the academic and practical circles have paid so much attention to similar financial models because they generated a miracle in GOME （Gome Electrical Appliances Holding Limited） and SUNING （Suning Appliance Co., Ltd.） respectively. But what＇s the influence of such a model on corporate profitability and risk？ Are similar financial models free lunches？ To seek for the answers to the above questions, in this paper, we take Gree （GREE Electric Appliances, Inc. of Zhuhai）, Midea （Guangdong Midea Electric Appliances Co. Ltd. Stores） and GOME for examples to carry out a comprehensive and in depth financial analysis. The conclusions of this paper are： The company with similar financial characteristics has higher profitability and risk level; Only the companies which meet special requirements need or can implement such a model and the identification and control of hidden risk can guarantee its success.
文摘This paper surnmarizes the historical experiences in venereal disease control in China during the 1950s.Venereal diseases had been all but eliminated in the whole country till 1964. However, along with the implementation of open-door policy and economic reform in the 1980s, the social environment was changed to a great extent in this country. Sexually transmitted diseases (STDs) were reintreduced in the Chinese mainland and new foci of infection established themselves in some cities. During the recent 8 years the national STD case-reporting and sentinel surveillance systems have been set up. The results of surveillance show that the annual incidence of STD has been on the increase. The existing factors associated with the increasing incidence of STD mainly are ; population movement , increasing affiuence in a part of population,the availability of multiple sexual partners (including the prostitution)and asymptomatic STD increased.Finally, the strategies for STD control are discussed in detail.
基金Supported by Disaster Reduction Foundation of Large Complex Project for Sutong Bridge(No.2006BAG04B06)
文摘Motion state of ship out of control in bridge area was analyzed.Motion procedure after losing control was divided into two steps.One is drift step within stopping period.The other is drift step without inertia,which is induced by wind and current.Mathematical model for motion of ship out of control,considering wind-induced drift,current-induced drift,stopping ability,etc.,was established.Dangerous collision areas for main pier and auxiliary piers were analyzed according to different calculation conditions.
文摘Engineering project management refers to the management through the whole process of engineering construction, including quality, time project time limit, safety, cost, environmental protection, and innovation, etc. The most important thing for construction enterprises to improve market competitiveness is to reduce enterprise costs by decreasing resource consumption in the construction, and control the consumptions within the project budget.
文摘Overbuilding, i.e. capping or decking, of roads assigned for the transportation of dangerous goods in major cities is being considered more often in many countries including Sweden. This type of facility introduces a number of risks and challenges related to rare events, such as dangerous goods accidents in tunnels, with a potential to cause substantial damage, e.g. collapse of buildings on the over site development. Many argue that the major problem associated with risk evaluation of such risks is the lack of commonly agreed acceptance criteria and regulations. Approaching the problem from a scientific perspective suggests that the root cause of this problem has not been adequately identified. However, there are strong indications that it is because the nature of the risk is not adequately addressed in risk analysis. In this study, we have structured the problem and propose ways of making progress in the evaluation of risk exposure and risk control. It is concluded that several challenges are inherent in the risk management of decking over routes for the transport of dangerous goods, and that these must be addressed in order to be able to control the risk. One of the complicating factors is that it is practically and economically impossible to construct the overbuilding so that it can withstand the maximum permissible explosion load. The main conclusions of this study are that overbuilding of dangerous goods routes has the potential to lead to catastrophic events, that the transport of dangerous goods in the future is associated with considerable intrinsic uncertainties, and that the possibility of supervising and controlling the transport of goods is limited once the route is in use.
基金Project (20507022) supported by the National Natural Science Foundation of ChinaProject (EREH050303) supported by the Foundation of Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health
文摘The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.
