Land use changes are regarded as landscape pattern change driven by many interactive natural and social-economic factors. Different combination of physical geographical elements induced the difference of spatio-tempor...Land use changes are regarded as landscape pattern change driven by many interactive natural and social-economic factors. Different combination of physical geographical elements induced the difference of spatio-temporal pattern of land use change. There are four physical geographical regions in Mongolian Autonomou County of Qian Gorlos of Jilin Province. Based on spatial analysis and statistical analysis, we conclude that the primary pattern of land use and the tendency of land use changes are all different in four physical geographical regions. During 1987 – 1996, the dominant land use change processes were from grassland or forest to arableland, from unused land to paddy and grassland to unused land. Though land use change is mainly affected by social and economic condition in short period, the composite characters of physical geographical elements controls land use dynamic process. The relationship between land use dynamic process and the character of physical geographical units differ in different regions. Possible human impacts on land use change are explored with application of buffer areas of series distance along main roads and radius around main settlements. A few models are built to describe the relationship between land use spatial change rates and distance to road and settlements. According to our result, the relationship with the proximity to roads was a negative liner function, with the change rate decreasing rapidly when moving away from roads. Within a distance of less 7.5km from main traffic lines, land use changes occur red more. The bulk of grassland was apt to be opened up for cultivation around the settlements and the transformation from dryland to paddy occurred within the distance of 1km away from settlements.展开更多
It is great important to the health development of urban agglomeration to correctly understand the formation and development law of regional structure of urban agglomeration.Employing the analysis methods like fractal...It is great important to the health development of urban agglomeration to correctly understand the formation and development law of regional structure of urban agglomeration.Employing the analysis methods like fractal theory and quantitative statistics,coupling with the use of remote sensing images and other spatial data,this article discusses the urban agglomeration of oasis on the northern slope of the Tianshan Mountains in an arid area,and conducts the researches on its city scale,spatial distribution and individual form from 1990 to 2005.The result shows that it has loose hierarchical scale structure and polarization trend of population distribution while its hierarchical scale structure tends to mature.Under the influence of natural conditions,the spatial layout of urban agglomeration of oasis has macro characteristics that suggest cities distributed along oasis edges(dense or sparse),spatially expand along rivers,and cluster around traffic branches.The connectivity among the cities is high and shows an internal organization form of a banding distribution.The whole spatial shape of the internal structure of cities presents a "dumbbell" form,with mononuclear phenomenon receding and multi-nuclear appearing gradually.Individual cities spatially expand along rivers,portraying a long strip appearance.It indicates that the urban agglomeration of oasis shows regular and close structure but with a tendency to be complicated form and the loose structure.In the development of urban agglomeration,the authors recommend that the development of the city with good economic development conditions should be strengthened,and more attention be put into regional planning.展开更多
A new kind of region pair grey difference classifier was proposed. The regions in pairs associated to form a feature were not necessarily directly-connected, but were selected dedicatedly to the grey transition betwee...A new kind of region pair grey difference classifier was proposed. The regions in pairs associated to form a feature were not necessarily directly-connected, but were selected dedicatedly to the grey transition between regions coinciding with the face pattern structure. Fifteen brighter and darker region pairs were chosen to form the region pair grey difference features with high discriminant capabilities. Instead of using both false acceptance rate and false rejection rate, the mutual information was used as a unified metric for evaluating the classifying performance. The parameters of specified positions, areas and grey difference bias for each single region pair feature were selected by an optimization processing aiming at maximizing the mutual information between the region pair feature and classifying distribution, respectively. An additional region-based feature depicting the correlation between global region grey intensity patterns was also proposed. Compared with the result of Viola-like approach using over 2 000 features, the proposed approach can achieve similar error rates with only 16 features and 1/6 implementation time on controlled illumination images.展开更多
The purpose of this study is to identify the determinants of adoption of sawah technology in Ashanti region of Ghana. It identifies those independent variables that explain adoption and can also facilitate further dis...The purpose of this study is to identify the determinants of adoption of sawah technology in Ashanti region of Ghana. It identifies those independent variables that explain adoption and can also facilitate further dissemination and adoption of sawah technology. Sawah refers to leveled rice field surrounded by banks with inlet and outlet for irrigation and drainage. This study uses data from 108 farmers randomly selected from 198 sawah farmers in the study area. Regression analysis showed that age, educational level and year of experience in rice production were the personal factors that determined the adoption of sawah technology among the respondents. The result further showed that contact with extension agents, attendance in previous sawah trainings, land tenure arrangement, yield from sawah farm and attributes of sawah technology determined adoption. This study suggested that adoption of sawah technology should be targeted at young, educated and experienced farmers. Also, security of land must be ascertained by farmers in order to enhance adoption, continuous and sustained use of sawah technology.展开更多
Experiments and analyses are carried out for GEO and joint GEO/IGSO precise orbit determination using data recorded by China's regional tracking network.Results show that joint GEO/IGSO orbit determination effecti...Experiments and analyses are carried out for GEO and joint GEO/IGSO precise orbit determination using data recorded by China's regional tracking network.Results show that joint GEO/IGSO orbit determination effectively solves the problem of poor observation geometry for GEO satellites.The laser radial evaluation thus confirms that precision is as good as less than 0.1 m.In the case of joint orbit determination,solving the empirical acceleration can reduce errors introduced by the imprecise solar radiation pressure model used for Chinese satellites.This method also improves the accuracy of orbit prediction in the radial direction.The ephemeris accuracy is thus improved and the ephemeris can provide a better service to users with navigation and positioning requirements.展开更多
基金the auspices of the Knowledge Innovation Project of the Chinese Academy of sciences (KZCXI - Y - 02)the Key Ninth Five-Year P
文摘Land use changes are regarded as landscape pattern change driven by many interactive natural and social-economic factors. Different combination of physical geographical elements induced the difference of spatio-temporal pattern of land use change. There are four physical geographical regions in Mongolian Autonomou County of Qian Gorlos of Jilin Province. Based on spatial analysis and statistical analysis, we conclude that the primary pattern of land use and the tendency of land use changes are all different in four physical geographical regions. During 1987 – 1996, the dominant land use change processes were from grassland or forest to arableland, from unused land to paddy and grassland to unused land. Though land use change is mainly affected by social and economic condition in short period, the composite characters of physical geographical elements controls land use dynamic process. The relationship between land use dynamic process and the character of physical geographical units differ in different regions. Possible human impacts on land use change are explored with application of buffer areas of series distance along main roads and radius around main settlements. A few models are built to describe the relationship between land use spatial change rates and distance to road and settlements. According to our result, the relationship with the proximity to roads was a negative liner function, with the change rate decreasing rapidly when moving away from roads. Within a distance of less 7.5km from main traffic lines, land use changes occur red more. The bulk of grassland was apt to be opened up for cultivation around the settlements and the transformation from dryland to paddy occurred within the distance of 1km away from settlements.
基金Under the auspices of Project of Xinjiang Development and Reform Commission (No 0743611)Western Doctor Plan of Chinese Academy of Sciences (No XBBS 200805)
文摘It is great important to the health development of urban agglomeration to correctly understand the formation and development law of regional structure of urban agglomeration.Employing the analysis methods like fractal theory and quantitative statistics,coupling with the use of remote sensing images and other spatial data,this article discusses the urban agglomeration of oasis on the northern slope of the Tianshan Mountains in an arid area,and conducts the researches on its city scale,spatial distribution and individual form from 1990 to 2005.The result shows that it has loose hierarchical scale structure and polarization trend of population distribution while its hierarchical scale structure tends to mature.Under the influence of natural conditions,the spatial layout of urban agglomeration of oasis has macro characteristics that suggest cities distributed along oasis edges(dense or sparse),spatially expand along rivers,and cluster around traffic branches.The connectivity among the cities is high and shows an internal organization form of a banding distribution.The whole spatial shape of the internal structure of cities presents a "dumbbell" form,with mononuclear phenomenon receding and multi-nuclear appearing gradually.Individual cities spatially expand along rivers,portraying a long strip appearance.It indicates that the urban agglomeration of oasis shows regular and close structure but with a tendency to be complicated form and the loose structure.In the development of urban agglomeration,the authors recommend that the development of the city with good economic development conditions should be strengthened,and more attention be put into regional planning.
基金Supported by the Joint Research Funds of Dalian University of Technology and Shenyang Automation Institute,Chinese Academy of Sciences
文摘A new kind of region pair grey difference classifier was proposed. The regions in pairs associated to form a feature were not necessarily directly-connected, but were selected dedicatedly to the grey transition between regions coinciding with the face pattern structure. Fifteen brighter and darker region pairs were chosen to form the region pair grey difference features with high discriminant capabilities. Instead of using both false acceptance rate and false rejection rate, the mutual information was used as a unified metric for evaluating the classifying performance. The parameters of specified positions, areas and grey difference bias for each single region pair feature were selected by an optimization processing aiming at maximizing the mutual information between the region pair feature and classifying distribution, respectively. An additional region-based feature depicting the correlation between global region grey intensity patterns was also proposed. Compared with the result of Viola-like approach using over 2 000 features, the proposed approach can achieve similar error rates with only 16 features and 1/6 implementation time on controlled illumination images.
文摘The purpose of this study is to identify the determinants of adoption of sawah technology in Ashanti region of Ghana. It identifies those independent variables that explain adoption and can also facilitate further dissemination and adoption of sawah technology. Sawah refers to leveled rice field surrounded by banks with inlet and outlet for irrigation and drainage. This study uses data from 108 farmers randomly selected from 198 sawah farmers in the study area. Regression analysis showed that age, educational level and year of experience in rice production were the personal factors that determined the adoption of sawah technology among the respondents. The result further showed that contact with extension agents, attendance in previous sawah trainings, land tenure arrangement, yield from sawah farm and attributes of sawah technology determined adoption. This study suggested that adoption of sawah technology should be targeted at young, educated and experienced farmers. Also, security of land must be ascertained by farmers in order to enhance adoption, continuous and sustained use of sawah technology.
基金supported by the National Natural Science Foundation of China (Grant No.41074020)
文摘Experiments and analyses are carried out for GEO and joint GEO/IGSO precise orbit determination using data recorded by China's regional tracking network.Results show that joint GEO/IGSO orbit determination effectively solves the problem of poor observation geometry for GEO satellites.The laser radial evaluation thus confirms that precision is as good as less than 0.1 m.In the case of joint orbit determination,solving the empirical acceleration can reduce errors introduced by the imprecise solar radiation pressure model used for Chinese satellites.This method also improves the accuracy of orbit prediction in the radial direction.The ephemeris accuracy is thus improved and the ephemeris can provide a better service to users with navigation and positioning requirements.
