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WSNs (wireless sensor networks) consist of thousands of tiny nodes having the capability of sensing, computation, and wireless communications. Unfortunately these devices are limited energy devices, that is means we must save energy as much as possible, to increase network life time as long as possible. In this paper we introduce NEER--normalized energy efficient routing protocol that increases network life time through switching between AODV protocol that depends on request-reply routing, and MRPC that depends on residual battery in routing. 相似文献
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丁贤 《数字社区&智能家居》2011,(13)
作为企业级数据仓库的路径图,元数据在企业级数据仓库的建设中起着重要的作用。设计一个描述能力强、内容完善的元数据,是有效实现企业级数据仓库功能的重要环节。该文通过对双向体系元数据管理系统的研究,给出了一个企业级数据仓库的元数据管理的解决方案。该方案能够支持从企业级数据仓库子系统抽取元数据存储到元数据管理系统,同时也支持向数据仓库子系统提供其所需的元数据信息,解决诸多企业级数据仓库的运行管理问题,大大减少了企业级数据仓库的管理难度、保证了元数据的准确性、使得各子系统能高效地通信和稳定运行。 相似文献
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FEI Chun TANG Xue-fei 《中国电子科技》2005,3(3):218-221
The e-learning has attracted a popular attention as a kind of teaching mode. It links up teachers and learners at different places by offering study contents and intercommunications on the network. Teacher and learner are the two main roles in E-learning. Teachers or other trainers produce their own contents of courses through certain tools and manage these contents by the learning management system (LMS), and then learner can choose and study. These contents of courses are transmitted betwe… 相似文献
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知识管理系统的首要问题是知识建模,知识模型直接影响着整个系统知识的获取、共享、重用和推理。文章运用领域本体思想对锻造知识进行分类、总结,提出一种基于本体元模型驱动的锻造知识管理模型,初步构建了锻造知识领域本体,采用框架概念图表示锻造知识。文章还结合锻造工艺知识,给出了本体元模型驱动和概念图框架知识表示模型在锻造知识管理中的具体应用,并提出一种适合于本体元模型的推理方法,并将该方法用于锻造工艺知识推理。本体元模型驱动的知识库构建方法在组织锻造知识时,具有构建速度快、良好的互操作和知识共享等优点。 相似文献
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为解决水文信息共享问题,本文从分析水文数据本身固有的特性出发,建立了基于空问数据仓库的具有多层维度和度量属性的水文信息共事数据模型,结合面向对象的思想,提出水文信息单元,并探计了以之建立水文信息数据仓库的方案及其信息共享后的安全性问题. 相似文献
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This paper describes the system design and the components of a web-based multimedia interactive Telelearning system (MITS) with emphasis on metadata and media content management mechanisms. Metadata model is defined and exploited in designing the overall architecture to support courseware creating, management, delivery, and learner performance evaluation. Multimedia document architecture is used to describe the media contents which represent the course material. Metadata and media contents are generated, stored, and utilized to facilitate the search and on-demand presentation of learning objects. Learner preference, performance and progress information is maintained by profile database to make courseware presentation adaptable and more interactive. The system provides a multimedia interactive learning environment with easy-to-search and highly reusable learning objects. 相似文献