期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
基于概念的文档评价模型 被引量:4
1
作者 罗三定 冯元勇 +1 位作者 沈德耀 贾维嘉 《计算机工程》 CAS CSCD 北大核心 2002年第8期79-80,283,共3页
理解文档的内容和查询的真实意图是提高搜索引擎智能水平的一种有效途径。提出了一种以分析概念及其关系为基础来理解文档、揣摩查询意图的模型。在该模型中,结合用户背景知识构造一个用户概念库,将文档及查询要求转化为概念集,并适当... 理解文档的内容和查询的真实意图是提高搜索引擎智能水平的一种有效途径。提出了一种以分析概念及其关系为基础来理解文档、揣摩查询意图的模型。在该模型中,结合用户背景知识构造一个用户概念库,将文档及查询要求转化为概念集,并适当扩充查询要求概念集,最后将两概念集转化为特征向量,计算其相似度,作为文档的评价值。文中详细给出了概念库及必需的概念运算的数学模型。 展开更多
关键词 概念 文档评价模型 搜索引擎 概念库 INTERNET
下载PDF
The Development of a Geographic Information System (GIS) to Document Research in an Everglades Physical Model
2
作者 S. Aich T.W. Dreschel +1 位作者 E.A. Cline F.H. Sklar 《Journal of Environmental Science and Engineering》 2011年第3期289-302,共14页
The Loxahatchee Impoundment Landscape Assessment (LILA) facility is a unique physical model of the Everglades ecosystem. LILA has a closed-loop water delivery system and consists of four 0.08 square kilometer (-8 h... The Loxahatchee Impoundment Landscape Assessment (LILA) facility is a unique physical model of the Everglades ecosystem. LILA has a closed-loop water delivery system and consists of four 0.08 square kilometer (-8 ha) macrocosms, created to be replicates of one another and of the Everglades landscape. Built in 2003, LILA's purpose is to provide scientists with an opportunity to design and implement research concerning Everglades restoration techniques in an accessible, controlled and replicated Everglades environment. Key Everglades habitats were sculpted within LILA: tree islands, ridges, sloughs and alligator holes. Water levels and flows in each macrocosm are controlled independently, so that researchers can study the effects of hydrology on Everglades landscape and ecology. Studies have focused upon measuring survival and growth of native trees planted on the tree islands; measuring surface water and ground water movement and chemistry; studying wading bird feeding and the movement of prey species (crayfish); and measuring erosion and accretion on tree islands and ridges. We developed a Geographic Information System (GIS) data set to identify, characterize, and spatially reference the features of LILA and document research activities. This development included mapping the boundaries of the landscape features, creating a theoretical Digital Elevation Model (DEM) and describing the research projects being carried out. The creation of this GIS data set enhances the ability to schedule and coordinate research, assist scientists in the visualization and spatial representation of their research, and provide a resource for the storage, analysis and synthesis of valuable scientific information. 展开更多
关键词 CERP EVERGLADES everglades forever act GIS LILA ridge and slough tree island.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部