Using soil data of the Second National Field Survey,the soil fertility of wetland ecosystem of Dongting Lake was evaluated by using the technology of GIS and method of fuzzy evaluation.Integrated with the wetland actu...Using soil data of the Second National Field Survey,the soil fertility of wetland ecosystem of Dongting Lake was evaluated by using the technology of GIS and method of fuzzy evaluation.Integrated with the wetland actuality of Dongting Lake and particularity of paddy,seven factors (including soil organic matter,total nitrogen,total phosphorus,total potassium,available phosphorus,available potassium,and pH value),closely related with soil fertility,were chosen to establish the index system of synthetical evaluation.Based on the effect degree of each selected index on soil fertility,a judgment matrix was built,and the weight coefficient was determined by the method of correlation coefficient.Finally,under the support of the spatial analysis module of GIS (Geographic Information System),the spatial distribution properties of soil fertility in wetland ecosystem of Dongting Lake were studied.The results show that the soil fertility of Dongting Lake wetland ecosystem is not very good,and the area of type III and type IV achieves 69.8%.As a result,many countermeasures should be taken to improve the soil fertility.As for the spatial properties,the soil fertility level of central and west Dongting Lake is much higher than that of north and south part.The soil fertility of paddy field surpasses that of red soil,and the contents of soil organic matter and total nitrogen in paddy field are large.展开更多
The aim of this study is to identify the variables affecting land value. Examined land was selected from the village in Vientiane capital city Laos. Data was collected from 100 villages in center of Vientiane capital ...The aim of this study is to identify the variables affecting land value. Examined land was selected from the village in Vientiane capital city Laos. Data was collected from 100 villages in center of Vientiane capital city by using survey methods. A hedonic price analysis was conducted to determine the marginal return to different land characteristics using an econometric model corrected for correlation. Parcel characteristics such as distance to public park, village income, distance of population, number of the school within 500 meters buffer, distance to the temple, distance to the major market and distance to the business center （CBD）. Arc GIS 9.2 was applied to calculate the distance of the factors, after that SPSS 15.0 was used to calculate the land price characteristic based on hedonic price model. The results showed that the distance to the center of population was the main factor influencing to the land price, and followed by school and village income. Map of the land price before and after hedonic price analysis were produced. The land price valuation approaches based on hedonic price model for Vientiane capital city were developed and land price map were predicted. Hedonic price model and GIS were very useful for this research, and finally the policy of the land valuation based on GIS was developed.展开更多
Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evalu...Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evaluation index system during the foundation operating period. Such methods as analytic hierarchy process （AHP） , Delphi method and fuzzy comprehensive evaluation method are adopted to make the quantitative analysis on the risk factors and establish the risk judgment model. According to the actual engineering of Taizhou Bridge, the paper evaluates the risk of the foundation during the operating period at the condition of deep overlying stratum. The evaluation results can provide the reference for the risk management of the bridge foundation durin~ the ooerating period.展开更多
基金Projects(40971170,51039001) supported by the National Natural Science Foundation of ChinaProject(2007AA10Z222) supported by the National High Technology Research and Development Program of China
文摘Using soil data of the Second National Field Survey,the soil fertility of wetland ecosystem of Dongting Lake was evaluated by using the technology of GIS and method of fuzzy evaluation.Integrated with the wetland actuality of Dongting Lake and particularity of paddy,seven factors (including soil organic matter,total nitrogen,total phosphorus,total potassium,available phosphorus,available potassium,and pH value),closely related with soil fertility,were chosen to establish the index system of synthetical evaluation.Based on the effect degree of each selected index on soil fertility,a judgment matrix was built,and the weight coefficient was determined by the method of correlation coefficient.Finally,under the support of the spatial analysis module of GIS (Geographic Information System),the spatial distribution properties of soil fertility in wetland ecosystem of Dongting Lake were studied.The results show that the soil fertility of Dongting Lake wetland ecosystem is not very good,and the area of type III and type IV achieves 69.8%.As a result,many countermeasures should be taken to improve the soil fertility.As for the spatial properties,the soil fertility level of central and west Dongting Lake is much higher than that of north and south part.The soil fertility of paddy field surpasses that of red soil,and the contents of soil organic matter and total nitrogen in paddy field are large.
文摘The aim of this study is to identify the variables affecting land value. Examined land was selected from the village in Vientiane capital city Laos. Data was collected from 100 villages in center of Vientiane capital city by using survey methods. A hedonic price analysis was conducted to determine the marginal return to different land characteristics using an econometric model corrected for correlation. Parcel characteristics such as distance to public park, village income, distance of population, number of the school within 500 meters buffer, distance to the temple, distance to the major market and distance to the business center （CBD）. Arc GIS 9.2 was applied to calculate the distance of the factors, after that SPSS 15.0 was used to calculate the land price characteristic based on hedonic price model. The results showed that the distance to the center of population was the main factor influencing to the land price, and followed by school and village income. Map of the land price before and after hedonic price analysis were produced. The land price valuation approaches based on hedonic price model for Vientiane capital city were developed and land price map were predicted. Hedonic price model and GIS were very useful for this research, and finally the policy of the land valuation based on GIS was developed.
基金National Science and Technology Support Program of China(No.2009BAG15B02)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-180)
文摘Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evaluation index system during the foundation operating period. Such methods as analytic hierarchy process （AHP） , Delphi method and fuzzy comprehensive evaluation method are adopted to make the quantitative analysis on the risk factors and establish the risk judgment model. According to the actual engineering of Taizhou Bridge, the paper evaluates the risk of the foundation during the operating period at the condition of deep overlying stratum. The evaluation results can provide the reference for the risk management of the bridge foundation durin~ the ooerating period.
