共查询到18条相似文献,搜索用时 156 毫秒
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全国水利一张图建设与应用 总被引:1,自引:0,他引:1
针对信息化分建专用的建设模式带来的"技术标准缺乏、设施利用低效、数据共享困难、业务应用割据、信息更新滞后和安全体系薄弱"等一系列问题,结合各类水利业务对地图应用需求迫切的实际,以及水利信息系统纷纷围绕电子地图展开建设和应用的现状,以统一地图服务为依托建设支撑和服务于各类水利业务应用的基础信息平台,完成技术标准体系建立、基础设施云建设、多源水利数据整合、应用支撑服务开发、信息更新机制创建和安全保障体系构建等工作,建成全国水利一张图,并在多个重大水利信息化工程建设和各级水利部门广泛应用,根据使用过程中的反馈意见持续优化完善,推进信息技术与水利业务深度融合。 相似文献
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水利信息化技术标准是水利政务和业务活动过程中应遵守的技术标准和行为规范,其体系完备性和标准适用性至关重要。在借鉴使用水利对象管理水利数据基础上,立足水利数据为核心,考察水利数据生命周期各重要环节,形成包括分类编码、传输交换、数据存储、图示表达、产品服务、建设管理和运行维护等7大类组成的水利信息化技术标准体系框架及其标准组成,是实现信息共享、保障应用协同、开展智能化应用的基础和保障。并对标准及其体系应实现的目标、标准范畴、标准分类及其体系构成等进行初步探索和研究。 相似文献
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文章在介绍Oracle数据库服务及相关体系软件结构的基础上,给出了利用Oracle数据仓库建立水利普查数据展现系统的实现技术,解决了因为原始数据库数据量庞大,数据关系复杂,导致数据查询速度慢等性能问题,并从多方面清晰、简洁、直观地展现水利普查数据. 相似文献
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孔丽云 《数字社区&智能家居》2014,(12):8087-8090
数据完整性是确保数据库数据安全的重要研究内容。通过DML触发器技术实现数据完整性控制,可有效防止由于对数据进行频繁的更新操作从而导致数据丢失或无效扩散。该文通过论述DML触发器的实现机制,并结合具体的开发实例,分析DML触发器在强制数据参照完整性、级联更新与删除、实现用户定义业务规则、更新不可更新视图等方面的应用基本步骤及设计技巧,反映了触发器应用在提高系统性能、简化数据库操作、维护数据完整性、有效性、增强数据库安全性、提高开发效率等方面的强大功能。 相似文献
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基于网络的地理信息系统研究 总被引:17,自引:2,他引:17
基于网络的地理信息系统是近年来地理信息系统发展的方向之一。文中介绍了国家基础设施(NII)和国家空间数据基础设施(NSDI),分析了信息高速公路(ISH)与地理信息系统之间的关系。提出网络地理信息系统的组织方式及网络地理信息系统的模型。 相似文献
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Efficient updating of discovered high-utility itemsets for transaction deletion in dynamic databases
《Advanced Engineering Informatics》2015,29(1):16-27
Most algorithms related to association rule mining are designed to discover frequent itemsets from a binary database. Other factors such as profit, cost, or quantity are not concerned in binary databases. Utility mining was thus proposed to measure the utility values of purchased items for finding high-utility itemsets from a static database. In real-world applications, transactions are changed whether insertion or deletion in a dynamic database. An existing maintenance approach for handling high-utility itemsets in dynamic databases with transaction deletion must rescan the database when necessary. In this paper, an efficient algorithm, called PRE-HUI-DEL, for updating high-utility itemsets based on the pre-large concept for transaction deletion is proposed. The pre-large concept is used to partition transaction-weighted utilization itemsets into three sets with nine cases according to whether they have large (high), pre-large, or small transaction-weighted utilization in the original database and in the deleted transactions. Specific procedures are then applied to each case for maintaining and updating the discovered high-utility itemsets. Experimental results show that the proposed PRE-HUI-DEL algorithm outperforms a batch two-phase algorithm and a FUP2-based algorithm in maintaining high-utility itemsets. 相似文献
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Is Sampling Useful in Data Mining? A Case in the Maintenance of Discovered Association Rules 总被引:4,自引:0,他引:4
By nature, sampling is an appealing technique for data mining, because approximate solutions in most cases may already be
of great satisfaction to the need of the users. We attempt to use sampling techniques to address the problem of maintaining
discovered association rules. Some studies have been done on the problem of maintaining the discovered association rules when
updates are made to the database. All proposed methods must examine not only the changed part but also the unchanged part
in the original database, which is very large, and hence take much time. Worse yet, if the updates on the rules are performed
frequently on the database but the underlying rule set has not changed much, then the effort could be mostly wasted. In this
paper, we devise an algorithm which employs sampling techniques to estimate the difference between the association rules in
a database before and after the database is updated. The estimated difference can be used to determine whether we should update
the mined association rules or not. If the estimated difference is small, then the rules in the original database is still
a good approximation to those in the updated database. Hence, we do not have to spend the resources to update the rules. We
can accumulate more updates before actually updating the rules, thereby avoiding the overheads of updating the rules too frequently.
Experimental results show that our algorithm is very efficient and highly accurate. 相似文献
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用基于元数据库的工作流调度数据仓库的更新 总被引:2,自引:2,他引:0
提出了一种新的解决方案,即通过基于元数据库的工作方法来调度、管理这个更新过程,从而减少了人工干预,提高了处理的自动化程度和效率 相似文献
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A query language, named Soil Data Language (SDL), for retrieving information from a Soil. Data Bank, is part of the ARSIS (A Relational Soil Information System) system, currently being developed in Greece. The interpreter of the language accepts input programs, expressed as SDL commands, and outputs the requested information. This paper describes design principles employed during the coding of the interpreter of the language. The derived program can be modified to cover eventual alterations to the specifications of language or the content and structure of the data bank. The study may be seen as an initiative to the design of Generalized Soil and Land Information Systems that primarily are concerned with the easy adaptation to a variety of National processing requirements. 相似文献