China's opening up has brought about the chances and the risks to the import trade at the same time.The thesis puts the focus on four kinds of risks in the import practice.They are respectively about policy change...China's opening up has brought about the chances and the risks to the import trade at the same time.The thesis puts the focus on four kinds of risks in the import practice.They are respectively about policy change,customers'operating capacity and credit status,exchange rate fluctuation and contract currency and contract terms.The impacts of those risks on the developing import trade in China are profound and lasting.展开更多
Objective To analyze the 2022 multiple-country monkeypox outbreak and assess its importation risk into China.Methods Data was from United States Centers for Disease Control and Prevention.We described the global epide...Objective To analyze the 2022 multiple-country monkeypox outbreak and assess its importation risk into China.Methods Data was from United States Centers for Disease Control and Prevention.We described the global epidemic and calculated concentration index to measure economic-related inequality.Importation risk into China was evaluated and ranked by using risk matrix method and Borda count method,respectively.Results As of July 29,2022,of 79 countries or territories,39(49.37%,39/79),17(21.52%,17/79),6(7.59%,6/79),12(15.19%,12/79),and 5(6.33%,5/79)country or territories identified cases<10,10-,51-,101-,and>1,000.There were economic-related health disparities exist in the distribution of cases(the concentration index=0.42,P=0.027),and the inequality disadvantageous to the rich(pro-poor).There were 12(15.38%,12/78),15(19.23%,15/78),6(7.69%,6/78),and 45(57.69%,45/78)countries or territories with extremely high,high,moderate,and low importation risk.United States and France ranked first with the highest Borda points of 156,and counts of zero.Conclusion Of 78 countries or territories,the key attention need be paid to the United States and France,relatively.As the epidemic progresses,preparing prevention and control measures to further reduce importation risk was crucial.展开更多
Objective To analyze the global epidemic status of the Ebola virus disease(EVD) and assess the importation risk into China.Methods Data from World Health Organization reports were used. We described the global epidemi...Objective To analyze the global epidemic status of the Ebola virus disease(EVD) and assess the importation risk into China.Methods Data from World Health Organization reports were used. We described the global epidemic status of EVD from 1976–2021, and assessed and ranked the importation risk of EVD from the diseaseoutbreaking countries into China using the risk matrix and Borda count methods, respectively.Results From 1976–2021, EVD mainly occurred in western and central Africa, with the highest cumulative number of cases(14,124 cases) in Sierra Leone, and the highest cumulative fatality rate(85%) in the Congo. Outbreaks of EVD have occurred in the Democratic Republic of the Congo and Guinea since 2018. The importation risk into China varies across countries with outbreaks of disease.The Democratic Republic of the Congo had an extremely high risk(23 Borda points), followed by Guinea and Liberia. Countries with a moderate importation risk were Nigeria, Uganda, Congo, Sierra Leone,Mali, and Gabon, while countries with a low importation risk included Sudan, Senegal, and Co te d’Ivoire.Conclusion China is under the risk of EVD importation with the globalization and severe epidemic status of EVD. Key attention need to be paid to the Democratic Republic of the Congo, Guinea, and Liberia. Therefore, it is necessary to prevent and prepare in advance for importation risk in China.展开更多
In order to reduce the calculation of the failure probability in the complex mechanical system reliability risk evaluation,and to implement importance analysis of system components effectively,the system fault tree wa...In order to reduce the calculation of the failure probability in the complex mechanical system reliability risk evaluation,and to implement importance analysis of system components effectively,the system fault tree was converted into five different Bayesian network models. The Bayesian network with the minimum conditional probability table specification and the highest computation efficiency was selected as the optimal network. The two heuristics were used to optimize the Bayesian network. The fault diagnosis and causal reasoning of the system were implemented by using the selected Bayesian network. The calculation methods of Fussel-Vesely( FV),risk reduction worth( RRW),Birnbaum measure( BM) and risk achievement worth( RAW) importances were presented. A certain engine was taken as an application example to illustrate the proposed method. The results show that not only the correlation of the relevant variables in the system can be accurately expressed and the calculation complexity can be reduced,but also the relatively weak link in the system can be located accurately.展开更多
Background The 2022-2023 mpox(monkeypox)outbreak has spread rapidly across multiple countries in the non-endemic region,mainly among men who have sex with men(MSM).In this study,we aimed to evaluate mpox's importa...Background The 2022-2023 mpox(monkeypox)outbreak has spread rapidly across multiple countries in the non-endemic region,mainly among men who have sex with men(MSM).In this study,we aimed to evaluate mpox's importation risk,border screening effectiveness and the risk of local outbreak in Chinese mainland.Methods We estimated the risk of mpox importation in Chinese mainland from April 14 to September 11,2022 using the number of reported mpox cases during this multi-country outbreak from Global.health and the international air-travel data from Official Aviation Guide.We constructed a probabilistic model to simulate the effectiveness of a border screening scenario during the mpox outbreak and a hypothetical scenario with less stringent quarantine requirement.And we further evaluated the mpox outbreak potential given that undetected mpox infections were introduced into men who have sex with men,considering different transmissibility,population immunity and population activity.Results We found that the reduced international air-travel volume and stringent border entry policy decreased about 94% and 69% mpox importations respectively.Under the quarantine policy,15-19% of imported infections would remain undetected.Once a case of mpox is introduced into active MSM population with almost no population immunity,the risk of triggering local transmission is estimated at 42%,and would rise to>95% with over six cases.Conclusions Our study demonstrates that the reduced international air-travel volume and stringent border entry policy during the COvID-19 pandemic reduced mpox importations prominently.However,the risk could be sub-stantially higher with the recovery of air-travel volume to pre-pandemic level.Mpox could emerge as a public health threat for Chinese mainland given its large MSM community.展开更多
随着电力系统的数字化和智能化发展,配变重过载预测成为了实现智能状态检修的关键技术之一。配变过载时空因子在现实场景中通常呈偏置分布。其中,部分高风险罕见(high risk and rare,HRR)因子一旦出现,将对变压器造成无法逆转的伤害。为...随着电力系统的数字化和智能化发展,配变重过载预测成为了实现智能状态检修的关键技术之一。配变过载时空因子在现实场景中通常呈偏置分布。其中,部分高风险罕见(high risk and rare,HRR)因子一旦出现,将对变压器造成无法逆转的伤害。为此,该文提出一种基于提高关联规则关键重要性(improved association rules‐criticality importance,IAR‐CI)模型的配变过载预测方法。首先,考虑内部与外部因素,收集多个数据源并建立配变运行状态数据库,且通过ICA识别与配变重过载强关联的罕见高危时段与HRR;其次,基于关键性重要度(criticality importance,CI)度量计算,设计一种因子权重计算方法,准确衡量因子的风险权重;最后,应用TBFP‐Growth算法,增强模型的运行效率。采用中国南方某地区电网数据进行算例仿真。研究表明,该方法能够提升配变重过载的预测性能,有助于后续巡检、检测策略的合理统筹和科学规划,可在降低电力设备运维检修成本的同时提高供电的可靠性。展开更多
文摘China's opening up has brought about the chances and the risks to the import trade at the same time.The thesis puts the focus on four kinds of risks in the import practice.They are respectively about policy change,customers'operating capacity and credit status,exchange rate fluctuation and contract currency and contract terms.The impacts of those risks on the developing import trade in China are profound and lasting.
基金partly supported by the National Natural Science Foundation of China[grant numbers 72122001,71934002]the National Key Research and Development Project of China[grant number 2021ZD0114101,2021ZD0114104,2021ZD0114105]+2 种基金National Statistical Science Research Project[grant numbers 2021LY038]the Fundamental Research Funds for the Central Universities supported by Global Center for Infectious Disease and Policy Research&Global Health and Infectious Diseases Group,of Peking University[grant number 202204]National Science and Technology Project on Development Assistance for Technology,Developing China-ASEAN Public Health Research and Development Collaborating Center[grant number KY202101004]
文摘Objective To analyze the 2022 multiple-country monkeypox outbreak and assess its importation risk into China.Methods Data was from United States Centers for Disease Control and Prevention.We described the global epidemic and calculated concentration index to measure economic-related inequality.Importation risk into China was evaluated and ranked by using risk matrix method and Borda count method,respectively.Results As of July 29,2022,of 79 countries or territories,39(49.37%,39/79),17(21.52%,17/79),6(7.59%,6/79),12(15.19%,12/79),and 5(6.33%,5/79)country or territories identified cases<10,10-,51-,101-,and>1,000.There were economic-related health disparities exist in the distribution of cases(the concentration index=0.42,P=0.027),and the inequality disadvantageous to the rich(pro-poor).There were 12(15.38%,12/78),15(19.23%,15/78),6(7.69%,6/78),and 45(57.69%,45/78)countries or territories with extremely high,high,moderate,and low importation risk.United States and France ranked first with the highest Borda points of 156,and counts of zero.Conclusion Of 78 countries or territories,the key attention need be paid to the United States and France,relatively.As the epidemic progresses,preparing prevention and control measures to further reduce importation risk was crucial.
基金funded by the National Natural Science Foundation of China[Grant No.71934002,Grant No.72122001]。
文摘Objective To analyze the global epidemic status of the Ebola virus disease(EVD) and assess the importation risk into China.Methods Data from World Health Organization reports were used. We described the global epidemic status of EVD from 1976–2021, and assessed and ranked the importation risk of EVD from the diseaseoutbreaking countries into China using the risk matrix and Borda count methods, respectively.Results From 1976–2021, EVD mainly occurred in western and central Africa, with the highest cumulative number of cases(14,124 cases) in Sierra Leone, and the highest cumulative fatality rate(85%) in the Congo. Outbreaks of EVD have occurred in the Democratic Republic of the Congo and Guinea since 2018. The importation risk into China varies across countries with outbreaks of disease.The Democratic Republic of the Congo had an extremely high risk(23 Borda points), followed by Guinea and Liberia. Countries with a moderate importation risk were Nigeria, Uganda, Congo, Sierra Leone,Mali, and Gabon, while countries with a low importation risk included Sudan, Senegal, and Co te d’Ivoire.Conclusion China is under the risk of EVD importation with the globalization and severe epidemic status of EVD. Key attention need to be paid to the Democratic Republic of the Congo, Guinea, and Liberia. Therefore, it is necessary to prevent and prepare in advance for importation risk in China.
基金National Natural Science Foundations of China(Nos.61164009,61463021)the Science Foundation of Education Commission of Jiangxi Province,China(No.GJJ14420)+1 种基金the Young Scientists Object Program of Jiangxi Province,China(No.20144BCB23037)the Graduate Innovation Foundation of Jiangxi Province,China(No.YC2014-S364)
文摘In order to reduce the calculation of the failure probability in the complex mechanical system reliability risk evaluation,and to implement importance analysis of system components effectively,the system fault tree was converted into five different Bayesian network models. The Bayesian network with the minimum conditional probability table specification and the highest computation efficiency was selected as the optimal network. The two heuristics were used to optimize the Bayesian network. The fault diagnosis and causal reasoning of the system were implemented by using the selected Bayesian network. The calculation methods of Fussel-Vesely( FV),risk reduction worth( RRW),Birnbaum measure( BM) and risk achievement worth( RAW) importances were presented. A certain engine was taken as an application example to illustrate the proposed method. The results show that not only the correlation of the relevant variables in the system can be accurately expressed and the calculation complexity can be reduced,but also the relatively weak link in the system can be located accurately.
基金This study was supported by grants from Key Program of the National Natural Science Foundation of China(82130093).
文摘Background The 2022-2023 mpox(monkeypox)outbreak has spread rapidly across multiple countries in the non-endemic region,mainly among men who have sex with men(MSM).In this study,we aimed to evaluate mpox's importation risk,border screening effectiveness and the risk of local outbreak in Chinese mainland.Methods We estimated the risk of mpox importation in Chinese mainland from April 14 to September 11,2022 using the number of reported mpox cases during this multi-country outbreak from Global.health and the international air-travel data from Official Aviation Guide.We constructed a probabilistic model to simulate the effectiveness of a border screening scenario during the mpox outbreak and a hypothetical scenario with less stringent quarantine requirement.And we further evaluated the mpox outbreak potential given that undetected mpox infections were introduced into men who have sex with men,considering different transmissibility,population immunity and population activity.Results We found that the reduced international air-travel volume and stringent border entry policy decreased about 94% and 69% mpox importations respectively.Under the quarantine policy,15-19% of imported infections would remain undetected.Once a case of mpox is introduced into active MSM population with almost no population immunity,the risk of triggering local transmission is estimated at 42%,and would rise to>95% with over six cases.Conclusions Our study demonstrates that the reduced international air-travel volume and stringent border entry policy during the COvID-19 pandemic reduced mpox importations prominently.However,the risk could be sub-stantially higher with the recovery of air-travel volume to pre-pandemic level.Mpox could emerge as a public health threat for Chinese mainland given its large MSM community.
文摘随着中国金融市场的高水平开放,中国应对外部输入性风险的压力将进一步上升。探索中国金融市场所面临的输入性风险动态变化并构建预警体系具有重要意义。本文运用时变参数向量自回归模型(TVP-VAR)和深度神经网络模型SCInet(Sample Convolution and Interaction Network),对我国金融市场输入性风险进行测度和前瞻性预警。研究发现:(1)TVP-VAR模型能有效识别极端风险事件发生前的风险积累,极端风险事件时期输入性风险水平会显著提高;(2)通过与主要发达国家(或地区)和发展中国家的输入性风险对比,发现发达经济体的输入性风险波动幅度较小,通过研究各国(地区)对我国的输入性风险,发现香港地区对我国内地的风险输入水平最高,以美国为主的发达国家和以印度为主的发展中国家也向我国输送了大量风险;(3)相比于其他机器学习和神经网络模型,SCInet模型具有最优的预警性能,在输入性风险异常波动前能提前预警。本研究或可为个人规避风险、企业可持续发展、国家金融稳定提供参考和帮助。
文摘随着电力系统的数字化和智能化发展,配变重过载预测成为了实现智能状态检修的关键技术之一。配变过载时空因子在现实场景中通常呈偏置分布。其中,部分高风险罕见(high risk and rare,HRR)因子一旦出现,将对变压器造成无法逆转的伤害。为此,该文提出一种基于提高关联规则关键重要性(improved association rules‐criticality importance,IAR‐CI)模型的配变过载预测方法。首先,考虑内部与外部因素,收集多个数据源并建立配变运行状态数据库,且通过ICA识别与配变重过载强关联的罕见高危时段与HRR;其次,基于关键性重要度(criticality importance,CI)度量计算,设计一种因子权重计算方法,准确衡量因子的风险权重;最后,应用TBFP‐Growth算法,增强模型的运行效率。采用中国南方某地区电网数据进行算例仿真。研究表明,该方法能够提升配变重过载的预测性能,有助于后续巡检、检测策略的合理统筹和科学规划,可在降低电力设备运维检修成本的同时提高供电的可靠性。
