共查询到20条相似文献,搜索用时 156 毫秒
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Visual Basic中的ADO事件编程 总被引:3,自引:0,他引:3
介绍了ADO编程模型,讨论了ADO中的事件模型,以及ADO事件在VB中的应用,给出了ADO事件的框架结构,讨论了ADO中的Will事件和它们之间的关系以及编程实现。 相似文献
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CORBA命名服务在TMN中的应用 总被引:1,自引:0,他引:1
首先讲述了命名服务运用于现代网管中的必然趋势,重点分析了命名服务的基本原理,在TMN中的技术实现,如何实现网管系统中的命名管理等,最后提出改进意见。 相似文献
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选择继承在多重继承中的应用技术 总被引:1,自引:0,他引:1
继承是解决软件可重用问题的有效途径,尤其是多重继承为解决软件可重用问题提供了灵活性。本文从软件可重用性观点出发,讨论了面向对象中的继承机制,就继承和多重继承实现中的不足,提出了选择继承机制,并作了较深入的讨论,最后给出了多重继承实现中的改进方法。 相似文献
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本文通过分析办公自动化建设和发展,归纳了办公自动化建设中的特点以及办公自动化在现阶段应用中的特定现象,总结了办公自动化系统在信息社会的重要性,展望了未来信息社会中的具有广阔发展空间和应用前景。 相似文献
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ODP系统的安全结构 总被引:3,自引:0,他引:3
在任何计算机环境中,安全性是非常重要的,特别是在计算机网络和开放式分布处理系统中更为重要,本文介绍了ODP系统中的安全结构,从扩充ISO/OSI环境中的安全结构,ODP环境中的安全服务与安全域这几个方面阐明了ODP环境中的安全结构。 相似文献
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软构件技术在信息系统开发中的应用研究 总被引:8,自引:0,他引:8
以高等院校教务管理系统的开发为背景,提出了一个基于软构件技术,适合于小型应用软件开发的过程模型和组织模型,介绍了基于主题文档的分析方法在高等院校教务管理中的应用,提出了一个基于原子文档关联矩阵发现系统中大粒度构件的方法,对系统中的构件进行了层次划分,给出了高等院校教务管理系统中的构件抽取实例,并探讨了利用构件组装应用软件的方法和过程。 相似文献
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本文主要介绍了变频调速在恒压供水系统中的应用,系统中采用了数字滤波技术和数字PID控制技术,有效的减小了系统中的干扰,提高了系统的稳定性。 相似文献
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阐述了分布式系统中的死锁问题,采用Petri网对分布式系统中的死锁进行分析,给出了几种解决死锁的模型,并分析了这些模型的优缺点,指出了分析和解决死锁的一般方法。 相似文献
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Abstract Information and Communication Technologies (ICT) are now widespread in Australian schools but with variation in how, where, when and how much they are used. Computers may be located in a computer laboratory, distributed throughout the school, or students may use their own laptop computers. IT may be a subject in its own right or ICT may be used across all areas of the curriculum. It is how ICT is used in the school setting that is important in providing students with the skills to be participate in a 'knowledge society'. This paper examines the ways in which information and communication technologies influence teaching and learning in five Australian schools. Data were gathered through observation, interviews and document analysis in schools operating at the elementary and secondary grades in relatively technology rich environments. Each of the schools participated in the Australian component of the Second Information Technology in Education Study – Module 2 (SITES-M2) of innovative pedagogical practices. Several of the studies were of specific projects where ICT was the key enabler of the learning programme. Others focused on an entire school's approach to ICT as an agent for changed approaches to learning. 相似文献
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以全国森林覆盖率最高的福建省为研究对象,利用2000~2017年夏季的MODIS EVI植被指数数据和气象与非气象因子进行协同分析,以揭示近17年福建植被的时空变化及其影响因子。结果表明:研究期内福建的EVI均值整体上升,从2000年的0.454上升至2017年的0.505,17 a间上升了11.2%,表明福建省的植被整体处于变好的状态,且在中部和西南部的变化最明显。相关分析表明,在研究期内,气象因子(气温和降水)对EVI变化的影响不显著,植被的变好主要为非气象因子的作用。EVI的提高主要得益于2003年福建省建设生态省后森林覆盖率的提高,并和2012年开始的水土流失治理有明显关系,这说明人类活动的积极作用对福建植被的变好起到了关键的作用。 相似文献
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关联规则挖掘技术研究进展* 总被引:5,自引:2,他引:3
为帮助人们深入研究关联规则挖掘技术,总结了关联规则的分类方法、评价方法以及相关技术的最新进展,特别是对关联规则的主要算法进行了详细的介绍,并探讨未来的发展方向。该研究比较系统全面,对将来进一步深入分析关联规则挖掘技术具有指导意义。 相似文献
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Abstract The term 'desktop publishing' has received much media coverage in recent months in both the commercial and educational press. School-based 'desktop publishing' packages are at the moment poor imitations of full-specification systems. This paper discusses the state of desktop publishing in education today and demonstrates the weaknesses of the systems available for use in the classroom. The skills required for desktop publishing are interrelated in a complex way and cannot be presented in a hierarchical fashion. A model of the functional processes involved is suggested in the paper and analysed in terms of the skills required. 相似文献
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Spatial heterogeneity in ecosystem functioning is a key component of ecological variability requiring special attention in the context of global change. A large history of human use has produced high physiognomic heterogeneity in Mediterranean ecosystems. However, the consequences for ecosystem functioning remain insufficiently understood. We analyzed spectral indicators of matter and energy fluxes in the land surface to classify the functional ecosystem heterogeneity in a Mediterranean region covering different management histories and protection types. We specifically analyzed the spatial variability in seasonal and annual patterns in the Normalized Difference Vegetation Index (NDVI), surface temperature (Ts) and albedo from five Landsat ETM images. Then we classified numerically this variability into ecosystem functional types (EFTs) and explored their seasonal dynamics in terms of photosynthetic radiation absorption and evapotranspiration. We identified eight main EFTs with ecologically relevant differences including contrasting dynamics in fPAR seasonality, great variation in incoming radiation reflection and differing evapotranspiration rates, particularly during the water-limitation period. Functional variability in natural vegetation mostly consisted in dissimilar annual rates of NDVI and albedo, whereas differences in seasonality were more evident in transformed areas. Similarly, the spatial distribution of EFTs was partly associated to protection, with two EFTs exclusive of protected areas and comparatively higher functional diversity in humanized areas. Landform effects on water availability in protected areas and human activities under different ecological settings were seemingly responsible for the large functional diversity of the region. We advocate for the explicit incorporation of multifunctional ecosystem heterogeneity in ecosystem management and monitoring designs. 相似文献
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《Ergonomics》2012,55(4):405-406
The extension force against resistance was recorded in 23 postures for 12 subjects to find explanations for the decrease in back strength in asymmetric postures. A reduction in muscle force in asymmetric postures was found up to 40%, but was strongly dependent on the plane in which asymmetry occurred, and on the posture to which it referred. A quantitative relationship between the forces exerted in different asymmetric postures is discussed, as a basis for formulating universal ergonomic guidelines for optimal working postures. The reduction in force in different asymmetric postures can be explained by length of the muscle, the activation of the muscle, and the moment angle of the muscle. 相似文献
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J.R. King 《Computers in Industry》1983,4(1):59-62
Manufacturing industry is going through a period of unprecedented change as a result of the developments in micro-electronic technology. This is bringing about a transformation not only in hardware, in the form of computer-aided manufacturing, but in the manner in which production is organised and controlled.It is in the latter connection that the present paper sets out to review current developments and future trends. In particular the machine readable bar-code is seen as a key element in extending computerised control to cover not only the machines, but tools, materials and parts and their movement in the development of fully integrated manufacturing systems.As the move towards automation gathers pace it is forecast that manufacturing industry will become more process industry like in form, with consequences for the way in which production is organised and controlled.Finally consideration is given to the manner in which these current developments in the field of production are giving rise to a structural alteration in industrial labour requirements in which, in the future, fewer people will be required but on highly enriched work tasks. 相似文献
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A new mining approach for uncertain databases using CUFP trees 总被引:1,自引:0,他引:1
Chun-Wei Lin 《Expert systems with applications》2012,39(4):4084-4093
In the past, many algorithms have been proposed to mine frequent itemsets from transactional databases, in which the presence or absence of items in transactions was certainly known. In some applications, items may also be uncertain in transactions with their existential probabilities ranging from 0 to 1 in the uncertain dataset. Apparently, the processing in uncertain datasets is quite different from those in certain datasets. The UF-tree algorithm was proposed to construct the UF-tree structure from an uncertain dataset and mine frequent itemsets from the tree. In the UF-tree construction process, however, only the same items with the same existential probabilities in transactions were merged together in the tree, thus causing many redundant nodes in the tree. In this paper, a new tree structure called the compressed uncertain frequent-pattern tree (CUFP tree) is designed to efficiently keep the related information in the mining process. In the CUFP tree, the same items will be merged in a branch of the tree even when the existential probabilities in transactions are not the same. A mining algorithm called the CUFP-mine algorithm is then proposed based on the tree structure to find uncertain frequent patterns. Experimental results show that the proposed approach has a better performance than UF-tree algorithm both in the execution time and in the number of tree nodes. 相似文献
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DTN网络中PRoPHET路由协议的改进 总被引:2,自引:0,他引:2
对DTN网络中PRoPHET路由协议进行了改进,在采用基于效用值来选择DTN路由下一跳的同时,充分利用了临时簇内的端到端的连接.另外,当网络中发生了DTN拥塞时,把拥塞节点上紧急程度低的信息转移到临时簇的周围其它节点,然后传输紧急程度高的信息到拥塞节点.仿真结果表明,与DTN网络中路由协议PRoPHET相比,改进后的路由方法提高了数据包的成功发送率,降低了平均发送延时. 相似文献