基于土地利用/覆盖的甘肃省景观生态风险时空变化特征

甘肃省景观类型丰富多样,在中国西部地区的生态安全中起关键性作用,也为当地发展提供着重要的物质基础和生态服务。由于气候变化和人类不合理活动的影响,甘肃省部分地区生态环境的安全与稳定遭到严峻挑战。本研究基于欧洲航空局全球土地利用/覆盖数据（CCI-LC）,利用动态度、转移矩阵方法分析了2005-2019年甘肃省土地利用/覆盖变化特征;通过构建景观生态风险指数并运用空间自相关分析法分析了景观生态风险的空间分布特征。结果显示：1)2005-2019年间,裸地面积减少最多,变化率1.88%,耕地次之,变化率2.31%;草地面积增加最多,变化率1.83%,建设用地次之,变化率191.08%。2）所有土地利用/覆盖类型中,建设用地的动态度最高且在整个研究时期内变化速率都保持在较高水平,综合动态度最大的时期为2010-2019年。3）土地利用/覆盖转移矩阵主要表现为耕地、林地、草地、裸地之间的转入与转出以及其他土地类型向建设用地的转入。4)2019年整体的生态风险值较2005年明显上升。其中低风险区和较低风险区面积最多,转化最频繁;中等风险区、较高风险区和高风险区面积虽然较少,但都存在不同程度的增长。...     

The Research on the Construction of Concentrative Residence and Ecological Human Habitat Environment in the Rural Area of Rapidly Urbanizing Region

Under the background of the new rural construction in China, it is an important scientific question and an urgent social task to construct the harmonious society and to achieve the sustainable regional development on how to construct concentrative residence and manage the human habitat environment in the fast industrializing and typically urbanizing area. This paper analyzed the problems in the construction of the human habitat envi- ronment in the rural area of southern Jiangsu, discussed the methodologies of planning and design for rural con- centrative residence, researched the human habitat environment improvement technologies, and put forward the resolution of the recycling community for the rural inhabitation, which aimed at demonstrating the practicing in rapidly urbanizing regions.     

A Caculation Method of Portfolio Investment under the Risk Mininiz

According to the security investment theory of Markowitz,this paper presents aCaculation method of portfolio investment under the risk minimization,and some mathematic expres-sions of the efficient frontier for portfolio investment are conducted.Based on these,the efficientfrontier is proved as a parabola,and a practical caculation process is given.     

Monitoring and Assessment of Tie on the Caiyuanba Yangtze Bridge

The monitoring and assessment scheme of the Caiyuanba Yangtze Bridge is present by sensitivity analysis. The mechanics character of the six ties is studied by numerical simulation, and then the sensor location and selection are discussed considering the technique of sensor and construction situation. The trend of the displacement at the sensor location is analyzed according to different damage level of ties, the pattern associating with several displacements which are sensitive to damage at ties is bring forward to improve assessment reliability. The result can assist implement of structural health monitoring system to the same type as this bridge.     

Conditional Value-at-Risk and Its Use in Credit Risk Measurement of Banks

Credit risk, the major risk of bank, is more and more intense during the period of economic restructuring in China. In view of the flaw of present risk measurement system, Conditional Value-at-Risk is used for the credit risk measurement which is better than Value-at-Risk. This paper creates the model ,while gives the method and procedure for solving it. So CVaRof credit combination is produced, which is just the early warning value of credit risk. At last, it is concluded that the CVaRrisk measurement is too difficult to use widely at present in china, then some advice is provided.     

Risk Decision-making Method of Slope Resistant Engineering

Considering the character of slope resistant engineering invest benefit, in line with security and economy balmaced, combining initial investment and anticipated hazard loss, disaster resistant engineering should be satisfied with the criterion of minimum cost. Decision tree model is adopted as analyzing means, and risk decision-making of slope design is carried out. Project input-output radio adopting dynamic analysis can reflect project investment benefit more accurately. At last this paper analyzes some questions in process of slope resistant engineering with benefits enumerate.     

Correlation and Arithmetic of Operational Risk Measurement Basing on Loss Distribution Approach

Based on the principles of operational risk measurement provided by Basel II,the paper discusses the problem of operational risk correlations among different business lines / risk types.The correlation coefficients between the aggregate losses among different business lines / risk types are calculated.Copula arithmetic is put forward to compute correlation coefficients matrix of aggregate losses.Besides,the result is used to calculate the capital requirement of operational risk.     

Power Frequency Electric Field Caused by EHV Lines and Its Effect

Mathematical model of power frequency electric field is established based on Charge Simulation Method(CSM) to analyze power frequency electric field caused by EHV lines with overhead ground wires and its effect, which are entering the megalopolis. Calculative method on the electric field under the transmission lines is analyzed and validated. According to the criterion of environmental evaluation, the distributing characteristic of electric field is summarized, in case of various arrangement manners of lines. At last, some advice and methods of eliminating electric field under the transmission lines entering the megalopolis is proposed with regard to protecting environment.     

Study on Landscape Planning of Mourtcainous City

:In accordance with the problems, occurred in the mountainous city's construction, especially the crises such as the destruction of ecological and humanistic environment, the loss of traditional culture and characteristics and the disorder of urban structure, this paper discusses the distinctive landscape characteristic of mountainous city thoroughly.     

Contracts of risk sharing of the enterprise, the employee and the dealer

The output of the enterprise changes with the change of natural states, therefore it brings relatively great risk to enterprise. The enterprise hopes to reduce the same kind of risk through more contracts than one kind of contract of risk sharing. This paper presents a new method to disperse the same kind of risk in two kinds of ways. Basing on principal-agent theory, through the optimum contract of risk sharing, the Pareto-optimum solving is solved-the optimum contract of risk sharing. The employee shares some risks through the optimum contract of risk sharing between the enterprise and the employee-when the output is high, the employee's income increases; when the output is low, the income decreases. In order to reduce the risk of the enterprise further, the dealer also shares the risk. To maximize the utility of the enterprise, the Pareto optimum solving is given-another optimum contract of risk. The dealer offers following contract of risk sharing to the enterprise-when the output is high, the dealer receives the repayment; when the output is low, the enterprise is compensated. The enterprise, the employee and the dealer share the risk together, thus the risk of the enterprise is reduced to relatively great degree.