Hybrid Peer-to-Peer （P2P） systems that construct overlay networks structured among superpeers have great potential in that they can give the benefits such as scalability, search speed and network traffic, taking adv...Hybrid Peer-to-Peer （P2P） systems that construct overlay networks structured among superpeers have great potential in that they can give the benefits such as scalability, search speed and network traffic, taking advantages of superpeer-based and the structured P2P systems. In this article, we enhance keyword search in hybrid P2P systems by constructing a tree-based index overlay among directory nodes that maintain indices, according to the load and popularity of a keyword. The mathematical analysis shows that the keyword search based on semi-structured P2P overlay can improve the search performance, reducing the message traffic and maintenance costs.展开更多
Groundwater levels are gradually declining in basins around the world due to anthropogenic and natural factors.Climate is not the only factor contributing to change in groundwater levels,population growth and economic...Groundwater levels are gradually declining in basins around the world due to anthropogenic and natural factors.Climate is not the only factor contributing to change in groundwater levels,population growth and economic progress are leading to increased water demand.Areas used for agricultural irrigation are expanding,necessitating the use of artificial groundwater recharge as a method to sustain pumping and enhance storage.The present study delineates potential locations of significant groundwater resources that already exist using a geostatistical approach as a method to identify potential groundwater recharge zones.The Multi-Influencing Factors(MIF)technique was applied to determine the relationship between different landscape and climatic factors that influence groundwater recharge.Factors include topography,climate,hydrogeology,population,economic change,and geology.Integration of these factors enabled the identification of potential locations of groundwater suitable for artificial recharge efforts based on weights derived through the MIF technique.We applied these weights to derive a groundwater recharge index(GRI)map.The map was delineated into three groundwater recharge zones classified by their potential areal coverage as a metric for recharge suitability,namely low,medium and high suitability,occupying areas of 8625 km2(30.06%),9082 km2(31.65%),and 10,989 km~2(38.29%),respectively.Our findings have important implications for designing sustainable groundwater development and land-use plans for the coming century.展开更多
In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the ...In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the Analytic Hierarchy Process(AHP)in combination with Geographic Information Systems(GIS)to evaluate the potential groundwater zones in the Gombora watershed within the Omo Gibe basin in Ethiopia.Combining these two tools provided a detailed map showing potential groundwater areas.These zones are determined based on various thematic maps containing information about geology,soil texture,lineament density,slope,land use,and drainage density.The AHP method combines these data layers by assigning weights to each layer based on its importance for groundwater recharge.These weighted layers are then overlaid using a GIS platform to produce a conclusive map of potential groundwater areas.The groundwater potential within the watershed was qualitatively divided into five categories with area coverages of very good(1.6%),good(7.4%),moderate(21.4%),poor(51.6%),and very poor(17.9%)of thewatershed area.The accuracy of the groundwater potential zones was evaluated using the receiver operating characteristic(ROC)curve and the area under the curve(AUC),producing good results(AUC=75.5%).This research has shown that integrating AHP with GIS can effectively pinpoint potential groundwater zones.Additionally,the findings could play a key role in determining suitable locations for new groundwater wells and supplying valuable insights to decision-makers to aid in planning and implementing sustainable strategies for managing groundwater resources in the watershed.展开更多
基金supported by the Korea Research Foundation Grant funded by the Korean Government(MOEHRD) under Grant No.KRF-2007-314-D00223.
文摘Hybrid Peer-to-Peer （P2P） systems that construct overlay networks structured among superpeers have great potential in that they can give the benefits such as scalability, search speed and network traffic, taking advantages of superpeer-based and the structured P2P systems. In this article, we enhance keyword search in hybrid P2P systems by constructing a tree-based index overlay among directory nodes that maintain indices, according to the load and popularity of a keyword. The mathematical analysis shows that the keyword search based on semi-structured P2P overlay can improve the search performance, reducing the message traffic and maintenance costs.
文摘Groundwater levels are gradually declining in basins around the world due to anthropogenic and natural factors.Climate is not the only factor contributing to change in groundwater levels,population growth and economic progress are leading to increased water demand.Areas used for agricultural irrigation are expanding,necessitating the use of artificial groundwater recharge as a method to sustain pumping and enhance storage.The present study delineates potential locations of significant groundwater resources that already exist using a geostatistical approach as a method to identify potential groundwater recharge zones.The Multi-Influencing Factors(MIF)technique was applied to determine the relationship between different landscape and climatic factors that influence groundwater recharge.Factors include topography,climate,hydrogeology,population,economic change,and geology.Integration of these factors enabled the identification of potential locations of groundwater suitable for artificial recharge efforts based on weights derived through the MIF technique.We applied these weights to derive a groundwater recharge index(GRI)map.The map was delineated into three groundwater recharge zones classified by their potential areal coverage as a metric for recharge suitability,namely low,medium and high suitability,occupying areas of 8625 km2(30.06%),9082 km2(31.65%),and 10,989 km~2(38.29%),respectively.Our findings have important implications for designing sustainable groundwater development and land-use plans for the coming century.
基金supported by the National Science Foundation-Hydrologic Science Program。
文摘In regions with unpredictable rainfall and limited water supply,it’s crucial to pinpoint areas with high potential for groundwater and find the best spots for groundwater resource development.This study utilizes the Analytic Hierarchy Process(AHP)in combination with Geographic Information Systems(GIS)to evaluate the potential groundwater zones in the Gombora watershed within the Omo Gibe basin in Ethiopia.Combining these two tools provided a detailed map showing potential groundwater areas.These zones are determined based on various thematic maps containing information about geology,soil texture,lineament density,slope,land use,and drainage density.The AHP method combines these data layers by assigning weights to each layer based on its importance for groundwater recharge.These weighted layers are then overlaid using a GIS platform to produce a conclusive map of potential groundwater areas.The groundwater potential within the watershed was qualitatively divided into five categories with area coverages of very good(1.6%),good(7.4%),moderate(21.4%),poor(51.6%),and very poor(17.9%)of thewatershed area.The accuracy of the groundwater potential zones was evaluated using the receiver operating characteristic(ROC)curve and the area under the curve(AUC),producing good results(AUC=75.5%).This research has shown that integrating AHP with GIS can effectively pinpoint potential groundwater zones.Additionally,the findings could play a key role in determining suitable locations for new groundwater wells and supplying valuable insights to decision-makers to aid in planning and implementing sustainable strategies for managing groundwater resources in the watershed.
