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Pricing Catastrophe Options with Credit Risk in a Regime-Switching Model
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作者 XU Yajuan WANG Guojing 《应用概率统计》 CSCD 北大核心 2024年第4期572-587,共16页
In this paper,we consider the price of catastrophe options with credit risk in a regime-switching model.We assume that the macroeconomic states are described by a continuous-time Markov chain with a finite state space... In this paper,we consider the price of catastrophe options with credit risk in a regime-switching model.We assume that the macroeconomic states are described by a continuous-time Markov chain with a finite state space.By using the measure change technique,we derive the price expressions of catastrophe put options.Moreover,we conduct some numerical analysis to demonstrate how the parameters of the model affect the price of the catastrophe put option. 展开更多
关键词 PRICING catastrophe option credit risk REGIME-SWITCHING measure change
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Hyper Catastrophe on 4-Dimensional Canards
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作者 Kiyoyuki Tchizawa Shuya Kanagawa 《Advances in Pure Mathematics》 2024年第4期196-203,共8页
When discovering the potential of canards flying in 4-dimensional slow-fast system with a bifurcation parameter, the key notion “symmetry” plays an important role. It is of one parameter on slow vector field. Then, ... When discovering the potential of canards flying in 4-dimensional slow-fast system with a bifurcation parameter, the key notion “symmetry” plays an important role. It is of one parameter on slow vector field. Then, it should be determined to introduce parameters to all slow/fast vectors. It is, however, there might be no way to explore for another potential in this system, because the geometrical structure is quite different from the system with one parameter. Even in this system, the “symmetry” is also useful to obtain the potentials classified by R. Thom. In this paper, via the coordinates changing, the possible way to explore for the potential will be shown. As it is analyzed on “hyper finite time line”, or done by using “non-standard analysis”, it is called “Hyper Catastrophe”. In the slow-fast system which includes a very small parameter , it is difficult to do precise analysis. Thus, it is useful to get the orbits as a singular limit. When trying to do simulations, it is also faced with difficulty due to singularity. Using very small time intervals corresponding small , we shall overcome the difficulty, because the difference equation on the small time interval adopts the standard differential equation. These small intervals are defined on hyper finite number N, which is nonstandard. As and the intervals are linked to use 1/N, the simulation should be done exactly. 展开更多
关键词 Canards Flying 4-Dimensional Slow-Fast System Hyper catastrophe
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The role of AFAP1-AS1 in mitotic catastrophe and metastasis of triple-negative breast cancer cells by activating the PLK1 signaling pathway 被引量:2
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作者 SHUIZHONG CEN XIAOJIE PENG +9 位作者 JIANWEN DENG HAIYUN JIN ZHINAN DENG XIAOHUA LIN DI ZHU MING JIN YANWEN ZHU PUSHENG ZHANG YUNFENG LUO HONGYAN HUANG 《Oncology Research》 SCIE 2023年第3期375-388,共14页
Triple-negative breast cancer(TNBC)is characterized by fast growth,high metastasis,high invasion,and a lack of therapeutic targets.Mitosis and metastasis of TNBC cells are two important biological behaviors in TNBC ma... Triple-negative breast cancer(TNBC)is characterized by fast growth,high metastasis,high invasion,and a lack of therapeutic targets.Mitosis and metastasis of TNBC cells are two important biological behaviors in TNBC malignant progression.It is well known that the long noncoding RNA AFAP1-AS1 plays a crucial role in various tumors,but whether AFAP1-AS1 is involved in the mitosis of TNBC cells remains unknown.In this study,we investigated the functional mechanism of AFAP1-AS1 in targeting Polo-like Kinase 1(PLK1)activation and participating in mitosis of TNBC cells.We detected the expression of AFAP1-AS1 in the TNBC patient cohort and primary cells by in situ hybridization(ISH),northern blot,fluorescent in situ hybridization(FISH)and cell nucleus/cytoplasm RNA fraction isolation.High AFAP1-AS1 expression was negatively correlated with overall survival(OS),disease-free survival(DFS),metastasis-free survival(MFS)and recurrence-free survival(RFS)in TNBC patients.We explored the function of AFAP1-AS1 by transwell,apoptosis,immunofluorescence(IF)and patient-derived xenograft(PDX)models in vitro and in vivo.We found that AFAP1-AS1 promoted TNBC primary cell survival by inhibiting mitotic catastrophe and increased TNBC primary cell growth,migration and invasion.Mechanistically,AFAP1-AS1 activated phosphorylation of the mitosis-associated kinase PLK1 protein.Elevated levels of AFAP1-AS1 in TNBC primary cells increased PLK1 pathway downstream gene expression,such as CDC25C,CDK1,BUB1 and TTK.More importantly,AFAP1-AS1 increased lung metastases in a mouse metastasis model.Taken together,AFAP1-AS1 functions as an oncogene that activates the PLK1 signaling pathway.AFAP1-AS1 could be used as a potential prognostic marker and therapeutic target for TNBC. 展开更多
关键词 TNBC AFAP1-AS1 Mitotic catastrophe METASTASIS PLK1
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Novel Early-Warning Model for Customer Churn of Credit Card Based on GSAIBAS-Cat Boost
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作者 Yaling Xu Congjun Rao +1 位作者 Xinping Xiao Fuyan Hu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第12期2715-2742,共28页
As the banking industry gradually steps into the digital era of Bank 4.0,business competition is becoming increasingly fierce,and banks are also facing the problem of massive customer churn.To better maintain their cu... As the banking industry gradually steps into the digital era of Bank 4.0,business competition is becoming increasingly fierce,and banks are also facing the problem of massive customer churn.To better maintain their customer resources,it is crucial for banks to accurately predict customers with a tendency to churn.Aiming at the typical binary classification problem like customer churn,this paper establishes an early-warning model for credit card customer churn.That is a dual search algorithm named GSAIBAS by incorporating Golden Sine Algorithm(GSA)and an Improved Beetle Antennae Search(IBAS)is proposed to optimize the parameters of the CatBoost algorithm,which forms the GSAIBAS-CatBoost model.Especially,considering that the BAS algorithm has simple parameters and is easy to fall into local optimum,the Sigmoid nonlinear convergence factor and the lane flight equation are introduced to adjust the fixed step size of beetle.Then this improved BAS algorithm with variable step size is fused with the GSA to form a GSAIBAS algorithm which can achieve dual optimization.Moreover,an empirical analysis is made according to the data set of credit card customers from Analyttica official platform.The empirical results show that the values of Area Under Curve(AUC)and recall of the proposedmodel in this paper reach 96.15%and 95.56%,respectively,which are significantly better than the other 9 common machine learning models.Compared with several existing optimization algorithms,GSAIBAS algorithm has higher precision in the parameter optimization for CatBoost.Combined with two other customer churn data sets on Kaggle data platform,it is further verified that the model proposed in this paper is also valid and feasible. 展开更多
关键词 Customer churn early-warning model IBAS GSAIBAS-CatBoost
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List of 85 typical catastrophic landslides from March 2004 to February 2024
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作者 Rui-chen Chen Yong-shuang Zhang 《China Geology》 CAS CSCD 2024年第2期369-370,共2页
Landslides are one of the most dangerous natural hazards that cause significant property damage and loss of life.Landslides often destroy farmland,villages,houses,factories,schools,roads and other facilities,injuring ... Landslides are one of the most dangerous natural hazards that cause significant property damage and loss of life.Landslides often destroy farmland,villages,houses,factories,schools,roads and other facilities,injuring humans and livestock.Sometimes,entire towns are devastated by landslides.Due to their pervasiveness,varied triggering factors,and sudden occurrence,landslides are currently one of the most challenging natural disasters to prevent and mitigate. 展开更多
关键词 stated FARMLAND catastrophIC
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Subarachnoid hemorrhage misdiagnosed as acute coronary syndrome leading to catastrophic neurologic injury: A case report
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作者 Jun-Ming Lin Xiao-Jun Yuan +2 位作者 Guang Li Xin-Rong Gan Wen-Hua Xu 《World Journal of Clinical Cases》 SCIE 2024年第1期148-156,共9页
BACKGROUND Elevated levels of cardiac troponin and abnormal electrocardiogram changes are the primary basis for clinical diagnosis of acute coronary syndrome(ACS).Troponin levels in ACS patients can often be more than... BACKGROUND Elevated levels of cardiac troponin and abnormal electrocardiogram changes are the primary basis for clinical diagnosis of acute coronary syndrome(ACS).Troponin levels in ACS patients can often be more than 50 times the upper reference limit.Some patients with subarachnoid hemorrhage(SAH)also show electrocardiogram abnormalities,myocardial damage,and elevated cardiac biomarkers.Unlike ACS patients,patients with SAH only have a slight increase in troponin,and the use of anticoagulants or antiplatelet drugs is prohibited.Because of the opposite treatment modalities,it is essential for clinicians to distinguish between SAH and ACS.CASE SUMMARY A 56-year-old female patient was admitted to the emergency department at night with a sudden onset of severe back pain.The final diagnosis was intraspinal hematoma in the thoracic spine.We performed an emergency thoracic spinal canal hematoma evacuation procedure with the assistance of a microscope.Intraoperatively,diffuse hematoma formation was found in the T7-T10 spinal canal,and no obvious spinal vascular malformation changes were observed.Postoperative head and spinal magnetic resonance imaging(MRI)showed a small amount of SAH in the skull,no obvious abnormalities in the cervical and thoracic spinal canals,and no abnormal signals in the lumbar spinal canal.Thoracoab-dominal aorta computed tomography angiography showed no vascular malfor-mation.Postoperative motor system examination showed Medical Research Council Scale grade 1/5 strength in both lower extremities,and the patient experienced decreased sensation below the T12 rib margin and reported a Visual Analog Scale score of 3.CONCLUSION Extremely elevated troponin levels(more than 50 times the normal range)are not unique to coronary artery disease.SAH can also result in extremely high troponin levels,and antiplatelet drugs are contraindicated in such cases.Emergency MRI can help in the early differential diagnosis,as a misdiagnosis of ACS can lead to catastrophic neurological damage in patients with spontaneous spinal SAH. 展开更多
关键词 Acute coronary syndrome Spontaneous spinal subdural hematoma MISDIAGNOSIS catastrophic neurological injury Case report
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Research progress of pain catastrophizing in patients with lumbar disc herniation
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作者 Ting Xiong Long-Fan Piao 《Frontiers of Nursing》 2024年第3期253-258,共6页
Pain catastrophization is one of the negative emotional factors and an important psychological factor associated with patients with lumbar disc herniation(LDH).Currently,the concept of pain catastrophization of LDH is... Pain catastrophization is one of the negative emotional factors and an important psychological factor associated with patients with lumbar disc herniation(LDH).Currently,the concept of pain catastrophization of LDH is relatively mature abroad;however,there are only few research studies on this in China.To understand the status quo of pain catastrophization(PC)in patients with LDH and its influencing factors,the intervention measures of PC and their efficacy were further analyzed.In the present paper,the research status of PC at home and abroad is briefly expounded,and the influencing factors and clinical intervention measures for PC are analyzed.This paper reviews the concept of PC,the assessment tools,influencing factors,and the relevant intervention measures.In order to evaluate the pain degree of patients,understand the incidence of pain in patients,and improve the cure rate and quality of life of patients,the basic situation of patients with pain disaster is summarized to provide reference for medical personnel. 展开更多
关键词 lumbar disc herniation MEASURE NURSING PAIN pain catastrophizing pain factor
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Construction of Early-warning Model for Plant Diseases and Pests Based on Improved Neural Network 被引量:2
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作者 曹志勇 邱靖 +1 位作者 曹志娟 杨毅 《Agricultural Science & Technology》 CAS 2009年第6期135-137,154,共4页
By studying principles and methods related to early-warning model of plant diseases and using PSO method, parameter optimization was conducted to backward propagation neural network, and a pre-warning model for plant ... By studying principles and methods related to early-warning model of plant diseases and using PSO method, parameter optimization was conducted to backward propagation neural network, and a pre-warning model for plant diseases based on particle swarm and neural network algorithm was established. The test results showed that the construction of early-warning model is effective and feasible, which will provide a via- ble model structure to establish the effective early-warning platform. 展开更多
关键词 Backward propagation neural network Particle swarm algorithm Plant diseases and pests early-warning model
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Mitotic Catastrophe的研究进展 被引量:2
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作者 张博 周平坤 《细胞生物学杂志》 CSCD 2007年第6期849-852,共4页
细胞死亡是多细胞生物生命过程中重要的生理或病理现象,可分为坏死和程序性细胞死亡,而后者根据死亡细胞的形态学和发生机制的不同又可分为凋亡、自吞噬和mitotic catastrophe,其中mitotic catastrophe是近年来才被揭示报道,是指细胞在... 细胞死亡是多细胞生物生命过程中重要的生理或病理现象,可分为坏死和程序性细胞死亡,而后者根据死亡细胞的形态学和发生机制的不同又可分为凋亡、自吞噬和mitotic catastrophe,其中mitotic catastrophe是近年来才被揭示报道,是指细胞在有丝分裂过程中死亡的现象,是一种发生在细胞有丝分裂期由于异常的细胞分裂而导致的细胞死亡,它常常伴随着细胞有丝分裂检查点的异常和基因或纺锤体结构的损伤而发生。现对mitotic catastrophe及相关的调控机制进行综述。 展开更多
关键词 MITOTIC catastrophe DNA损伤 细胞周期检查点 纺锤体
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CUSP CATASTROPHE MODEL OF INSTABILITY OF PILLAR IN ASYMMETRIC MINING 被引量:20
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作者 李江腾 曹平 《应用数学和力学》 EI CSCD 北大核心 2005年第8期1003-1008,共6页
关键词 矿柱 稳定性 势能 尖点突变 非对称开采
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CUSP CATASTROPHE MODEL OF INSTABILITY OF PILLAR IN ASYMMETRIC MINING 被引量:4
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作者 LI Jiang-teng(李江腾) CAO Ping(曹平) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2005年第8期1100-1106,共7页
A simplified mechanical model of pillar-hang wall was established in asymmetric mining and instability of the system was discussed by means of potential energy principle and cusp catastrophe theory. The necessary-suff... A simplified mechanical model of pillar-hang wall was established in asymmetric mining and instability of the system was discussed by means of potential energy principle and cusp catastrophe theory. The necessary-sufficient condition and the jump value of displacement of pillar and the released energy expressions were derived, which established foundation for quantifying of the instability of system. The results show that instability of the system is related to load and its stiffness distribution. The critical load increases with the increasing relative stiffness, and the system is more stable. On the contrary, the instability of system is likely to occur, and the released energy is larger in instability process, and the harm is more tremendous accordingly. Furthermore, an example was calculated, and the estimated results are in good agreement with the practical experience, which provide basis for mining order and arranging stope. 展开更多
关键词 PILLAR STABILITY potential energy cusp catastrophe asymmetric mining
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Assessment of Flood Catastrophe Risk for Grain Production at the Provincial Scale in China Based on the BMM Method 被引量:5
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作者 XU Lei ZHANG Qiao +1 位作者 ZHOU Ai-lian HUO Ran 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第12期2310-2320,共11页
Flood catastrophe risk assessment is imperative for the steady development of agriculture under the context of global climate change,and meanwhile,it is an urgent scientific issue need to be solved in agricultural ris... Flood catastrophe risk assessment is imperative for the steady development of agriculture under the context of global climate change,and meanwhile,it is an urgent scientific issue need to be solved in agricultural risk assessment discipline.This paper developed the methodology of flood catastrophe risk assessment,which can be shown as the standard process of crop loss calculation,Monte Carlo simulation,the generalized extreme value distribution(GEV) fitting,and risk evaluation.Data on crop loss were collected based on hectares covered by natural disasters,hectares affected by natural disasters,and hectares destroyed by natural disasters using the standard equation.Monte Carlo simulation based on appropriate distribution was used to expand sample size to overcome the insufficiency of crop loss data.Block maxima model(BMM) approach based on the extreme value theory was for modeling the generalized extreme value distribution(GEV) of flood catastrophe loss,and then flood catastrophe risk at the provincial scale in China was calculated.The Type III Extreme distribution(Weibull) has a weighted advantage of modeling flood catastrophe risk for grain production.The impact of flood catastrophe to grain production in China was significantly serious,and high or very high risk of flood catastrophe mainly concentrates on the central and eastern regions of China.Given the scenario of suffering once-in-a-century flood disaster,for majority of the major-producing provinces,the probability of 10% reduction of grain output is more than 90%.Especially,the probabilities of more than 15% decline in grain production reach up to 99.99,99.86,99.69,and 91.60% respectively in Anhui,Jilin,Liaoning,and Heilongjiang.Flood catastrophe assessment can provide multifaceted information about flood catastrophe risk that can help to guide management of flood catastrophe. 展开更多
关键词 flood catastrophe risk assessment block maxima model(BMM) provincial scale China
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Safety thickness analysis of tunnel floor in karst region based on catastrophe theory 被引量:14
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作者 YANG Xiao-li XIAO Hai-bo 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2364-2372,共9页
Based on the tunnel shape, span and depth, the previous elliptical plate model and clamped beam model were modified.The modified model was applied to different situations. For the elliptical plate model, the water eff... Based on the tunnel shape, span and depth, the previous elliptical plate model and clamped beam model were modified.The modified model was applied to different situations. For the elliptical plate model, the water effects were considered. For the clamped beam model, water and horizontal stress were considered. Corresponding potential functions and cusp catastrophe models of rock system were established based on the catastrophe theory. The expressions of critical safety thickness were derived with necessary and sufficient conditions. The method was applied to the practical engineering. Some parameters related to the stability were discussed. The results show that elastic modulus and thickness are advantageous to the floor stability, and that the load, span,horizontal stress and water are disadvantageous to the floor stability. 展开更多
关键词 KARST catastrophe theory safety thickness tunnel floor STABILITY WATER
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Application of cusp catastrophe theory to reliability analysis of slopes in open-pit mines 被引量:17
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作者 YANG Kun, WANG Tongxu, MA Zhitao Key Laboratory of Mine Disaster Prevention and Control, Shandong University of Science and Technology, Qingdao 266510, China 《Mining Science and Technology》 EI CAS 2010年第1期71-75,共5页
A method of slope reliability analysis was developed by imposing a state equation on the limit equilibrium theory, given the basis of a fixed safety factor technique. Among the many problems of reliability analysis, t... A method of slope reliability analysis was developed by imposing a state equation on the limit equilibrium theory, given the basis of a fixed safety factor technique. Among the many problems of reliability analysis, the most important problem is to find a performance function. We have created a new method of building a limit state equation for planar slip surfaces by applying the mathematical cusp catastrophe theory. This new technique overcomes the defects in the traditional rigid limit equilibrium theory and offers a new way for studying the reliability problem of planar slip surfaces. Consequently, we applied the technique to a case of an open-pit mine and compared our results with that of the traditional approach. From the results we conclude that both methods are essentially consistent, but the reliability index calculated by the traditional model is lower than that from the catastrophic model. The catastrophe model takes into consideration two possible situations of a slope being in the limit equilibrium condition, i.e., it may or may not slip. In the traditional method, however, a slope is definitely considered as slipping when it meets the condition of a limit equilibrium. We conclude that the catastrophe model has more actual and instructive importance compared to the traditional model. 展开更多
关键词 slope engineering UNCERTAINTY cusp catastrophe reliability analysis
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Catastrophe theory-based risk evaluation model for water and mud inrush and its application in karst tunnels 被引量:18
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作者 ZHU Jian-qun LI Tian-zheng 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第5期1587-1598,共12页
This paper presents a risk evaluation model of water and mud inrush for tunnel excavation in karst areas.The factors affecting the probabilities of water and mud inrush in karst tunnels are investigated to define the ... This paper presents a risk evaluation model of water and mud inrush for tunnel excavation in karst areas.The factors affecting the probabilities of water and mud inrush in karst tunnels are investigated to define the dangerousness of this geological disaster.The losses that are caused by water and mud inrush are taken into consideration to account for its harmfulness.Then a risk evaluation model based on the dangerousness-harmfulness evaluation indicator system is constructed,which is more convincing in comparison with the traditional methods.The catastrophe theory is used to evaluate the risk level of water and mud inrush and it has great advantage in handling problems involving discontinuous catastrophe processes.To validate the proposed approach,the Qiyueshan tunnel of Yichang-Wanzhou Railway is taken as an example in which four target segments are evaluated using the risk evaluation model.Finally,the evaluation results are compared with the excavation data,which shows that the risk levels predicted by the proposed approach are in good agreements with that observed in engineering.In conclusion,the catastrophe theory-based risk evaluation model is an efficient and effective approach for water and mud inrush in karst tunnels. 展开更多
关键词 risk evaluation model water and mud inrush catastrophe theory karst area TUNNELING
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PRICING CATASTROPHE OPTIONS WITH COUNTERPARTY CREDIT RISK IN A REDUCED FORM MODEL 被引量:2
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作者 徐亚娟 王过京 《Acta Mathematica Scientia》 SCIE CSCD 2018年第1期347-360,共14页
In this paper, we study the price of catastrophe Options with counterparty credit risk in a reduced form model. We assume that the loss process is generated by a doubly stochastic Poisson process, the share price proc... In this paper, we study the price of catastrophe Options with counterparty credit risk in a reduced form model. We assume that the loss process is generated by a doubly stochastic Poisson process, the share price process is modeled through a jump-diffusion process which is correlated to the loss process, the interest rate process and the default intensity process are modeled through the Vasicek model: We derive the closed form formulae for pricing catastrophe options in a reduced form model. Furthermore, we make some numerical analysis on the explicit formulae. 展开更多
关键词 PRICING catastrophe option counterparty risk measure change reduced form model
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China agricultural outlook for 2015–2024 based on China Agricultural Monitoring and Early-warning System(CAMES) 被引量:12
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作者 XU Shi-wei LI Gan-qiong LI Zhe-min 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第9期1889-1902,共14页
The primary goal of Chinese agricultural development is to guarantee national food security and supply of major agricultural products. Hence, the scientiifc work on agricultural monitoring and early warning as wel as ... The primary goal of Chinese agricultural development is to guarantee national food security and supply of major agricultural products. Hence, the scientiifc work on agricultural monitoring and early warning as wel as agricultural outlook must be strengthened. In this study, we develop the China Agricultural Monitoring and Early-warning System (CAMES) on the basis of a comparative study of domestic and international agricultural outlook models. The system is a dynamic and multi-market partial equilibrium model that integrates biological mechanisms with economic mechanisms. This system, which includes 11 categories of 953 kinds of agricultural products, could dynamical y project agricultural market supply and demand, assess food security, and conduct scenario analysis at different spatial levels, time scale levels, and macro-micro levels. Based on the CAMES, the production, consumption, and trade of the major agricultural products in China over the next decade are projected. The fol owing conclusions are drawn:i) The production of major agricultural products wil continue to grow steadily, mainly because of the increase in yield. i ) The growth of agricultural consumption wil be slightly higher than that of agricultural production. Meanwhile, a high self-sufifciency rate is expected for cereals such as rice, wheat, and maize, with the rate being stable at around 97%. i i) Agricultural trade wil continue to thrive. The growth of soybean and milk im-ports wil slow down, but the growth of traditional agricultural exports such as vegetables and fruits is expected to continue. 展开更多
关键词 agricultural outlook PROJECTION China Agricultural Monitoring and early-warning System(CAMES) agriculture of China
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A CATASTROPHE ANALYSIS ON THE STABILITY OF THE CRACK GROWTH IN THREE-POINT BENDING SPECIMENS 被引量:2
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作者 Wei Demin Fan Xuejun, Taiyuan Unversity of Technology, Taiyuan 030024 《Acta Mechanica Solida Sinica》 SCIE EI 1996年第2期179-183,共5页
This paper presents an attempt at the application of catastrophe theory to the stability analysis of J-controlled crack growth in three-point bending specimens. By introducing the solutions of J-integral in the comple... This paper presents an attempt at the application of catastrophe theory to the stability analysis of J-controlled crack growth in three-point bending specimens. By introducing the solutions of J-integral in the completely yielding state for the ideal plastic material, the critical condition of losing stability for the crack propagation in the specimen is obtained, based on the cusp catastrophe theory. The process of the crack growth from geometrical sense is described. 展开更多
关键词 crack growth STABILITY cusp catastrophe J-INTEGRAL three-point bending specimen
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Application of the catastrophe progression method in predicting coal and gas outburst 被引量:18
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作者 ZHANG Tian-jun REN Shu-xin +2 位作者 LI Shu-gang ZHANG Tian-cai XU Hong-jie 《Mining Science and Technology》 EI CAS 2009年第4期430-434,共5页
Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensi... Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines. 展开更多
关键词 standard transformation catastrophe progression method coal and gas outburst
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Deformation early-warning index for heightened gravity dam during impoundment period 被引量:10
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作者 Bo Chen Zi-shen Huang +1 位作者 Teng-fei Bao Zheng Zhu 《Water Science and Engineering》 EI CAS CSCD 2021年第1期54-64,共11页
The mechanical parameters of materials in a dam body and dam foundation tend to change when dams are reinforced in aging processes.It is important to use an early-warning index to reflect the safety status of dams,par... The mechanical parameters of materials in a dam body and dam foundation tend to change when dams are reinforced in aging processes.It is important to use an early-warning index to reflect the safety status of dams,particularly of heightened projects in the impoundment period.Herein,a new method for monitoring the safety status of heightened dams is proposed based on the deformation monitoring data of a dam structure,a statistical model,and finite-element numerical simulation.First,a fast optimization inversion method for estimation of dam mechanical parameters was developed,which used the water pressure component extracted from a statistical model,an improved inversion objective function,and a genetic optimization iterative algorithm.Then,a finite element model of a heightened concrete gravity dam was established,and the deformation behavior of the dam with rising water levels in the impoundment period was simulated.Subsequently,mechanical parameters of aged dam parts were calculated using the fast optimization inversion method with simulated deformation and the water pressure deformation component obtained by the statistical model under the same conditions of water pressure change.Finally,a new earlywarning index of dam deformation was constructed by means of the forward-simulated deformation and other components of the statistical model.The early-warning index is useful for forecasting dam deformation under different water levels,especially high water levels. 展开更多
关键词 Concrete gravity dam Parameter inverse analysis Structural health monitoring early-warning index Finite element simulation
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