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1.
目前比较成熟的安全模型大部分是访问控制策略模型,用于描述与维护系统中数据的保密性和完整性。基于角色的访问控制（RBAC）借鉴了人们熟知的用户组、权限组以及职责分离的概念和应用,以角色为中心的权限管理更符合公司和企业的实际管理方式,所以RBAC模型的研究和应用发展得非常快。通过给用户分配恰当的角色,使角色拥有一定的权限成为访问控制的主体,可以提高管理效率。介绍了基于角色的出租车管理系统的部分设计;阐述了模块设计与应用和数据库的设计理念;成功地实现了对不同角色的安全访问控制,有效地解决了安全访问控制问题。 相似文献
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共词分析法是科学计量学中最常用的方法之一。论文以共词分析法为工具,将CNKI数据库中有关竞争情报的研究文献作为分析对象,通过对这些文献高频关键词的共现分析,利用聚类分析与多维尺度分析方法以可视化方式来揭示目前国内竞争情报研究的演进态势。 相似文献
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对高校重点学科网络资源管理的现实意义进行了分析,阐述了应用清华同方专业信息资源建设与管理系统（TPI）建设高校重点学科网络资源导航数据库的步骤和方法,为数字图书馆资源管理提供了一套解决方案。 相似文献
4.
《International Journal of Information Management》2017,37(5):357-366
Mobile agent technology has been used in various applications including e-commerce, information processing, distributed network management, and database access. Information search and retrieval can be conducted by mobile agents in a decentralized system. As compared with the client/server model, the mobile agent approach has an advantage of saving network bandwidth and offering flexibility in information search and retrieval. In this paper, we present a model for mobile agents to select the most reputable information host to search and retrieve information. We use opinion-based belief structure to represent, aggregate and calculate the reputation of an information host. Since reputation is a multi-faced concept, our approach first allows the users to rank each information host's quality of service based on a set of evaluation categories. Then, a comprehensive, final reputation of the host is obtained by aggregating those specific category reputations. To recognize the subjective nature of a reputation, the transferable belief model is used to represent and rank the category reputation. Experiments are conducted using the Aglets technology to illustrate mobile agent migration. 相似文献
5.
以太网接入是实现宽带接入的主要方法之一.一个完整的宽带接人交换机软件系统应该包括交换机驱动程序、配置界面、应用程序和网络管理等部分.在接入交换设备中采用VLAN技术能够有效的利用带宽和增加数据的安全性.首先说明了接人交换机的体系结构,然后给出了交换机软件系统的整体框架,并着重讨论了宽带交换机软件系统各主要功能模块的设计与实现. 相似文献
6.
This paper evaluates the content of Google Scholar and seven other databases (Academic Search Elite, AgeLine, ArticleFirst, GEOBASE, POPLINE, Social Sciences Abstracts, and Social Sciences Citation Index) within the multidisciplinary subject area of later-life migration. Each database is evaluated with reference to a set of 155 core articles selected in advance—the most important studies of later-life migration published from 1990 to 2000. Of the eight databases, Google Scholar indexes the greatest number of core articles (93%) and provides the most uniform publisher and date coverage. It covers 27% more core articles than the second-ranked database (SSCI) and 2.4 times as many as the lowest-ranked database (GEOBASE). At the same time, a substantial proportion of the citations provided by Google Scholar are incomplete (32%) or presented without abstracts (33%). 相似文献
7.
本文就泵站无人值守的安防系统建设，提供了一个完善的设计方案，通过将电子围栏、视频监控、门禁管理、灯光照明、语音驱赶、声光报警等系统融合设计在一个安防系统中，通过远程管理的方式，最终满足了泵站无人值守的需要。 相似文献
8.
SQL注入攻击是一种利用客户端输入构建特殊SQL查询语句进行数据库攻击的攻击方式。开发一种三层架构的信息系统,可检测和过滤用户的非法输入,在数据层使用SP（Store Produce）存储过程进行数据存取,以更有效地防范SQL注入攻击,提升系统安全性能。 相似文献
9.
知识资本传承问题越来越受到知识型企业的关注,文章结合SECI模型和洋葱模型为企业的知识资本传承提供了一个合理的传承途径。潜移默化,建立员工知识沟通渠道;外部明示,对企业进行可行性分析并建立数据库系统;汇总组合,营造知识分享环境,内部升华,定期座谈交流。通过上述方法可以为企业知识资本传承提供一个明确的方向,合理的解决企业知识资本传承问题。 相似文献
10.
Following a general discussion on the philosophy and design of information systems, with particular attention to the definition, needs and psychology of the ultimate user of systems providing on-line access to biomedical information, the role of the documentalist, the differences between document retrieval and true information retrieval and the operational characteristics of on-line systems which affect their cost and hence their design and acceptability, the authors make some tentative predictions as to the future demand for such information retrieval services and their probable organizational form. A brief report is then presented on the principal findings and conclusions of a user's study of the Excerpta Medica system, the key features and history of which are briefly described. Based on the conclusions of this study, particularly as regards the complexity of the average search question, the role of the search formulators in determining the results of computer searching, the importance of secondary concepts for retrieval and the optimal level of specificity of a computer thesaurus, some of the changes in the Excerpta Medica system which are in the planning stage and will be incorporated into the system's Mark II version are outlined, as are the principal features of the two systems currently offering on-line access to the Excerpta Medica database in Western Germany and the U.S.A. Finally, attention is given to the planned partial hierarchic structuring of the Excerpta Medica thesaurus (Malimet), a project which is to be based largely on frequency counts of the existing database and the elimination of over-specific terms by posting under broader concepts. The results of some of the initial steps in this direction (i.e. frequency counts of portions of the database and the structuring of some of the terms used in the cancer field) are presented by way of illustration. 相似文献
11.
基于文献计量方法, 针对中国知网(CNKI)学术文献网络出版总库收录的门禁系统研究论文,分别从论文年代分布、著者及机构、关键词、期刊、学科类别、研究层次、被引频次7个方面对门禁系统的文献进行了统计分析,从一个层面揭示了国内门禁系统科学研究的情况。 相似文献
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13.
网络文献代理是近些年来才出现的一种新的文献获取方式,它突破了数据库网站或数据库订阅机构原有访问权限的限制,使得研究人员能够自主地、方便地查找自己所需的文献资料,本文通过对网络文献代理现象产生的背景、操作流程和发展现状的介绍,分析了网络文献代理这种新的文献获取途径的特点和优势,在此基础上进一步分析了网络文献代理目前存在的多种问题,提出了初步的应对策略。总之,网络文献代理有着现实的社会需求,对科研活动中文献的获取有较大的帮助,在今后很长一段时间内,网络文献代理现象将可能长期存在,但在其使用过程中需要相关部门加以规范和引导,努力避免严重侵权等行为的发生。 相似文献
14.
集群数据库内容管理系统的设计与实现 总被引：1，自引：0，他引：1
通过分析现有内容管理系统的不足,提出基于集群数据库的内容管理解决方案。采用基于RUP的UML建模方法、PHP、XML、AJAX等开发技术,构建一套以集群数据库为基础的统一内容管理系统,解决数据库、字段及目录的灵活定制和不同数字资源的分库管理问题,实现非结构化与半结构化数字资源的规范化采集、有效管理与充分利用。 相似文献
15.
A Comparison Between the Provision of Information to Engineering Designers in the UK and the USA 总被引：1，自引：0，他引：1
Understanding the information accessing activities of engineering designers has been a topic of considerable interest both to industrialists and researchers alike in forming the basic requirements and specification for document management systems, engineering database management systems and information delivery systems. As part of this effort studies have been undertaken to establish how the designers themselves access and distribute this information. However, such studies have been specific to the host country in which the research was originated and comparisons with the wider design community across the world have not possible to establish or quantify. This paper will present the salient findings and observations of a global comparison between engineering designers working within the UK and USA. It is based on two questionnaire surveys, one undertaken in each of the two countries, where over 300 designers were questioned. Thus, it is anticipated that this paper would serve to enhance the management of information and the associated information delivery systems on a world-wide basis. 相似文献
16.
本文以信息资源管理为主题收集了CNKI数据库近五年所刊载的研究论文,以论文的关键词为研究对象,对关键词进行词频统计,获得高频关键词,建立高频关键词矩阵,运用SPSS、Ucient软件,结合聚类分析和多维尺度分析两种多元统计方法,绘制出我国2007-2011年信息资源管理研究领域的研究热点与前沿的知识图谱,研究发现信息资源、图书馆、信息服务、知识管理仍是信息资源研究核心,而以信息技术为主的虚拟环境下的数字图书馆、电子政务、电子商务的信息资源管理将成为研究趋势。 相似文献
17.
VB是最流行的数据库应用程序开发工具之一,对VB中数据库访问技术进行了讨论,重点介绍了ADO对象模型编程方式访问数据库技术。 相似文献
18.
科研管理工作是高校工作的一个重要内容,现在高校越来越重视科研,导致科研项目繁多,增加了科研管理部门的工作量。针对这一现象,设计了高校科研管理系统,介绍了基于Web Services的B／S结构的关键技术,重点阐述了系统架构设计、功能设计以及实现方法。通过运用先进技术和工具对高校科研管理工作进行分析和抽象,将其信息化和规范化,降低开发成本,提高系统开发效率,对基于Web Services的系统开发提供了一种借鉴模式。 相似文献
19.
文章提出了将小波函数引入神经网络预测模型,对一个具有非线性、时变性、大滞后性特点的地铁站台内的CO2含量进行预测控制。而小波神经网络系统结合了小波分析和传统神经网络的优点,且可不断吸收环境新信息,有良好的函数学习能力和推广能力。最后实现了对具有大干扰性、大滞后性和不确定随机干扰因素的CO2含量进行了精确预测。 相似文献
20.
We study the behavior of single linear polyelectrolytes condensed by trivalent salt under the action of electric fields through computer simulations. The chain is unfolded when the strength of the electric field is stronger than a critical value. This critical electric field follows a scaling law against chain length, and the exponent of the scaling law is −0.77(1), smaller than the theoretical prediction, −3ν∕2 [R. R. Netz, Phys. Rev. Lett. 90, 128104 (2003)], and the one obtained by simulations in tetravalent salt solutions, −0.453(3) [P.-Y. Hsiao and K.-M. Wu, J. Phys. Chem. B 112, 13177 (2008)]. It demonstrates that the scaling exponent depends sensitively on the salt valence. Hence, it is easier to unfold chains condensed by multivalent salt of a smaller valence. Moreover, the absolute value of chain electrophoretic mobility increases drastically when the chain is unfolded in an electric field. The fact that the mobility depends on electric field and on chain length provides a plausible way to impart chain-length dependence in free-solution electrophoresis via chain unfolding transition induced by electric fields. Finally, we show that, in addition to an elongated structure, a condensed chain can be unfolded into a U-shaped structure. The formation of this structure in our study is purely a result of the electric polarization, not of the elastohydrodynamics dominated in sedimentation of polymers. 相似文献