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Changes of crop climate risk degree:a case study on cotton in Henan Province 被引量:2
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作者 QIAN Huaisui REN Yuyu LI Mingxia 《Journal of Geographical Sciences》 SCIE CSCD 2006年第3期355-362,共8页
The agricultural climate risk in the geographical transitional zones is very sensitive to climate change. Based on previous researches, this article established the cotton climate suitability model and the risk index ... The agricultural climate risk in the geographical transitional zones is very sensitive to climate change. Based on previous researches, this article established the cotton climate suitability model and the risk index to analyze the cotton climate risk degree in Henan Province. The result shows that, in the last 40 years, the cotton climate risk degree has a gradual increasing trend in which the precipitation plays a very important role, and the climate suitability and its deviation have different performances in the influence on the risk change in different phases; the increase rate of risk degree has significant regional and transitional characteristics, for example, from the eastern plain to the western mountains, the risk change rate becomes slower and slower, so the contrast between the central-southern Huang-Huai plain and the Funiu mountains is the most remarkable; and in the north-south direction, the contrast between the fast increase belt from the central-southern Huang-Huai plain to the middle Yellow River and the slow increase belt near the Yellow River is particularly remarkable, which is possibly the results of topographic and climatic transitional belt; and the risk change process also has obvious regional difference. For instance, abrupt change is an important characteristic in eastern Henan where this sudden change type has notable latitudinal difference, while in the western mountainous area it is very rare. Although the temperature change over the 40 years is still increasing in this area, the trend has reduced gradually since the end of the 1980s. 展开更多
关键词 climate risk degree COTTON climate change Henan Province
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Estimating the Degree of Earthquake Risk from Fault Characteristics
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作者 Hou Jianjun Bai Taixu Liang Haihua Han Mukang Department of Geology, Peking University, Beijing 100871 Ollier C. D. Center for Resource and Environmental Studies, Australia National University, Canberra ACT 0200, Australia 《Journal of Earth Science》 SCIE CAS CSCD 1998年第3期16-19,共4页
A theoretical model considering the relationship between fault characteristics and tectonic stress is proposed to quantify earthquake risk degree. The model is applied in practice to the fault along the southern margi... A theoretical model considering the relationship between fault characteristics and tectonic stress is proposed to quantify earthquake risk degree. The model is applied in practice to the fault along the southern margin of Weihe basin in Shaanxi Province, Northwestern China and fitted well with reality. 展开更多
关键词 earthquake risk degree fault movement probability fault unstable degree earthquake time approach degree.
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The risk evaluation of mine coal-dust explosion based on BP neural network 被引量:1
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作者 陈连军 程卫民 《Journal of Coal Science & Engineering(China)》 2007年第4期396-399,共4页
Introduced the theory of three types of hazardous sources, and it recognized and analysed such three types of hazardous sources as the factor of inherent hazardous source, factor of inducing hazardous source and facto... Introduced the theory of three types of hazardous sources, and it recognized and analysed such three types of hazardous sources as the factor of inherent hazardous source, factor of inducing hazardous source and factor of men, which affect the safety and reliability of coal-dust explosion risk system and then builds up the risk factor indices of coal-dust explosion according to analysis of conditions inducing the coal-dust explosion. It fixes the risk degree of coal-dust explosion risk system by analyzing loss probability and loss scope of risk system and by means of the probabilistic hazard evaluation method and risk matrix method, etc.. According to the feature of strong capability of nonlinear approximation of BP neural network, the paper designed the structure of BP neural network for the risk evaluation of the mine coal-dust explosion with BP neural network. And the weight of the network was finally determined by training the given samples so that the risk degree of samples to be measured could be exactly evaluated and the risk of mine coal-dust explosion could be alarmed in good time. 展开更多
关键词 coal dust explosion risk source risk degree neural network risk assessment
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3D Simulation of Storm Surge Disaster Based on Scenario Analysis
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作者 王晓玲 孙小沛 +3 位作者 张胜利 孙蕊蕊 李瑞金 朱泽彪 《Transactions of Tianjin University》 EI CAS 2016年第2期110-120,共11页
The occurrence of storm surge disaster is often accompanied with floodplain, overflow, dike breach and other complex phenomena, while current studies on storm surge flooding are more concentrated on the 1D/2D numerica... The occurrence of storm surge disaster is often accompanied with floodplain, overflow, dike breach and other complex phenomena, while current studies on storm surge flooding are more concentrated on the 1D/2D numerical simulation of single disaster scenario(floodplain, overflow or dike breach), ignoring the composite effects of various phenomena. Therefore, considering the uncertainty in the disaster process of storm surge, scenario analysis was firstly proposed to identify the composite disaster scenario including multiple phenomena by analyzing key driving forces, building scenario matrix and deducing situation logic. Secondly, by combining the advantages of k-ω and k-ε models in the wall treatment, a shear stress transmission k-ω model coupled with VOF was proposed to simulate the 3D flood routing for storm surge disaster. Thirdly, risk degree was introduced to make the risk analysis of storm surge disaster. Finally, based on the scenario analysis, four scenarios with different storm surge intensity(100-year and 200-year frequency) were identified in Tianjin Binhai New Area. Then, 3D numerical simulation and risk map were made for the case. 展开更多
关键词 SIMULATION storm surge disaster scenario analysis risk degree 3D SST k-ω turbulence model composite scenario
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The Quantitative Analysis on Leverage and its Effects
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作者 Yongkang Hu Hong Zhao 《Chinese Business Review》 2004年第6期79-81,65,共4页
Leverage of modem enterprise's financial management includes operating leverage and financial leverage. Both of them exist objectively, are not changeable with human's minds. They enlarge enterprise's benefit and r... Leverage of modem enterprise's financial management includes operating leverage and financial leverage. Both of them exist objectively, are not changeable with human's minds. They enlarge enterprise's benefit and risk, so they have both positive and negative effects. The degrees of them are measured as DOL and DFL. In financial management, the relationship between DOL and operating risk has regularity in quantity, and so does the relationship between DFL and financial risk. 展开更多
关键词 operating leverage financial leverage the effect of leverage operating risk financial risk degree of leverage
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Changes of citrus climate risk in subtropics of China 被引量:2
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作者 DUAN Hailai QIAN Huaisui +1 位作者 LI Mingxia DU Yaodong 《Journal of Geographical Sciences》 SCIE CSCD 2010年第6期818-832,共15页
Based on the citrus temperature, precipitation, sunlight and climate risk degree, the article divides subtropics of China into three types: the low risk region, the moderate risk region and the high risk region. The ... Based on the citrus temperature, precipitation, sunlight and climate risk degree, the article divides subtropics of China into three types: the low risk region, the moderate risk region and the high risk region. The citrus temperature risk increases with increasing latitude (except for the western mountainous area of subtropics of China). The citrus precipitation risk in the central part of subtropics of China is higher than that in the northern and western parts. The distributions of citrus sunlight risk are not consistent to those of the citrus precipitation risk. The citrus climate risk is mainly influenced by temperature. There is latitudinal zonal law for the distribution of the climate risk, that is, the climate risk increases with increasing latitude At the same time the climate risk in mountainous area is high and that in eastern plain area is low. There are differences in the temporal and spatial changes of the citrus climate. In recent 46 years, the citrus climate risk presents a gradual increasing trend in subtropics of China, especially it has been increasing fast since the 1980s. Because of the global warming, the low risk region in the eastern and southern parts has a gradual decreasing trend, however, the high risk region in the northern and western parts has an increasing trend and the high risk region has been extending eastward and southward. The article analyses the distribution of the citrus climate risk degree of reduction rates of 〉10%, 〉20% and 〉30% in subtropics of China, and studies their changes in different time periods. Results show that the risk is increasing from southeast to northwest. 展开更多
关键词 climate risk degree climate change climate risk dynamic assessment model climate suitability model CITRUS subtropics of China
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Prediction-based dynamic routing intelligent algorithm in power optical communication network
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作者 Guo Xuerang Li Feng +3 位作者 Zhu Bohan Zhang Zhijun Guo Qingrui Yang Huiting 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2022年第6期46-52,共7页
New energy power generation equipment has the characteristics of diurnal, perturbative, seasonal, and periodic power generation, which makes new power optical communication network(POCN) more dynamic and changeable. T... New energy power generation equipment has the characteristics of diurnal, perturbative, seasonal, and periodic power generation, which makes new power optical communication network(POCN) more dynamic and changeable. This is directly reflected in the dynamics of the link risk and service importance of the POCN. In this paper, aiming at the problem of the dynamic importance of service in POCN, and the resulting power optical communication network reliability decline problem, a new energy POCN dynamic routing intelligence algorithm based on service importance prediction is proposed. Based on the short-term power generation of new energy power station, the importance of each service and the risk degree of each link are predicted. Link weights are dynamically adjusted, and k-shortest path(KSP) algorithm is used to calculate route results. When network resources are insufficient, low-importance services can give way to prevent a large number of high-importance services from being blocked. Simulation results show that compared with the traditional KSP algorithm, the prediction-based dynamic routing intelligent(P-DRI) algorithm can reduce the service blocking probability by 55.59%, and reduce the average importance of blocking services by 44.77% at the cost of about 6.17% of the calculation delay. 展开更多
关键词 new power optical communication network(POCN) traffic diversion new energy power generation network risk degree
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