基于受众画像的新型耦合社交网络谣言传播模型研究

[目的/意义] 移动互联网时代谣言传播模式发生了巨大的变化,一方面谣言的扩散已不再局限于孤立的线下人际关系网络或线上互联网,谣言在耦合网络之间的传播变得更加普遍。另一方面,以往通过概率方式研究谣言的传播存在很大的不准确性,受众的个体特征差异对谣言的传播起到了更重要的作用。本文针对上述现象进行了研究。[方法/过程] 以受众的年龄作为两种网络的耦合依据,提出基于受众年龄的新型谣言传播的耦合社交网络（ASCN）。从受众的认知能力、匿名程度、权威性等基本特征,以及受众的从众心理、记忆效应、好友的影响作用等心理特征方面对受众进行画像,构建多维度函数实现基于受众画像的谣言传播模型。[结果/结论] 基于ASCN对本文提出的模型进行模拟仿真。结果表明,ACSN能够真实地反应出当前网络环境下谣言传播呈现出的"线下引起线上共鸣"、"线上溢散线下"的特征;受众的基本特征和心理特征能够对谣言传播产生巨大的影响,能更好地反映社交网络中谣言的传播规律。     

基于向量空间模型的科技情报用户画像及场景化服务推送研究

[目的] 为了满足情报3.0时代用户对科技情报服务个性化与智能化的要求,采用用户画像方法挖掘科技情报用户情报需求与偏好。[方法] 以TAM理论的两个关键因素（感知有用性与易用性）为理论基础,通过挖掘科技情报用户行为日志数据以及问卷调查等方法深入挖掘科技情报用户在不同情境下的科技情报需求偏好以及搜索行为习惯,以专家访谈法为基础,基于VSM理论构建科技情报用户画像模型。[结果] 通过协同过滤算法对不同场景的科技情报用户进行服务推送。[结论] 运用标签云技术（Tagxedo技术）为处于不同场景的科技情报用户定制有针对性的个性化服务方案是情报3.0时代一种有效的智能化服务途径。     

SQL Server数据库的访问安全研究

在研究现有RBAC模型的理论和性质基础上,建立了改进的分布式异构数据库访问模型,并采取PKI和PMI相结合的应用方案,解决了访问主体的网络认证和访问控制的安全问题。这种方案既保证了信息的机密性,又能保证信息具有不可抵赖性。     

个性化元搜索引擎的研究

针对现有搜索引擎的局限性和当前用户的个性化需求,以用户兴趣模型为基础,对个性化元搜索引擎的基本原理和结构、方法及关键技术进行了研究,并在此基础上提出了用户个性化元搜索引擎的简单实现。     

Investigation of behavior and perception of digital library users: A cognitive style perspective

Cognitive style is an influential factor in users’ information seeking. The study presented in this paper examines how users’ cognitive styles affect their behavior and perception in digital libraries. Fifty participants took part in this study. Two dimensions of cognitive styles were considered: (a) Field Dependence/Independence; (2) Verbalizer/Imager. The results showed that Intermediate users and Verbalizers have not only more positive perception, but they also complete the tasks in effective ways. Implications for the design of personalized digital libraries are also discussed.     

Website usage metrics: A re-assessment of session data

Metrics derived from user visits or sessions provide a means of evaluating Websites and an important insight into online information seeking behaviour, the most important of them being the duration of sessions and the number of pages viewed in a session, a possible busyness indicator. However, the identification of session (termed often ‘sessionization’) is fraught with difficulty in that there is no way of determining from a transactional log file that a user has ended their session. No one logs out. Instead a session delimiter has to be applied and this is typically done on the basis of a standard period of inactivity. To date researchers have discussed the issue of a time out delimiter in terms of a single value and if a page view time exceeds the cut-off value the session is deemed to have ended. This approach assumes that page view time is a single distribution and that the cut-off value is one point on that distribution. The authors however argue that page time distribution is composed of a number of quite separate view time distributions because of the marked differences in view times between pages (abstract, contents page, full text). This implies that a number of timeout delimiters should be applied. Employing data from a study of the OhioLINK digital journal library, the authors demonstrate how the setting of a time out delimiter impacts on the estimate of page view time and the number of estimated session. Furthermore, they also show how a number of timeout delimiters might apply and they argue that this gives a better and more robust estimate of the number of sessions, session time and page view time compared to an application of a single timeout delimiter.     

Evaluating WordBars in exploratory Web search scenarios

Web searchers commonly have difficulties crafting queries to fulfill their information needs; even after they are able to craft a query, they often find it challenging to evaluate the results of their Web searches. Sources of these problems include the lack of support for constructing and refining queries, and the static nature of the list-based representations of Web search results. WordBars has been developed to assist users in their Web search and exploration tasks. This system provides a visual representation of the frequencies of the terms found in the first 100 document surrogates returned from an initial query, in the form of a histogram. Exploration of the search results is supported through term selection in the histogram, resulting in a re-sorting of the search results based on the use of the selected terms in the document surrogates. Terms from the histogram can be easily added or removed from the query, generating a new set of search results. Examples illustrate how WordBars can provide valuable support for query refinement and search results exploration, both when vague and specific initial queries are provided. User evaluations with both expert and intermediate Web searchers illustrate the benefits of the interactive exploration features of WordBars in terms of effectiveness as well as subjective measures. Although differences were found in the demographics of these two user groups, both were able to benefit from the features of WordBars.     

Zero,single, or multi? Genre of web pages through the users’ perspective

The goal of the study presented in this article is to investigate to what extent the classification of a web page by a single genre matches the users’ perspective. The extent of agreement on a single genre label for a web page can help understand whether there is a need for a different classification scheme that overrides the single-genre labelling. My hypothesis is that a single genre label does not account for the users’ perspective. In order to test this hypothesis, I submitted a restricted number of web pages (25 web pages) to a large number of web users (135 subjects) asking them to assign only a single genre label to each of the web pages. Users could choose from a list of 21 genre labels, or select one of the two ‘escape’ options, i.e. ‘Add a label’ and ‘I don’t know’. The rationale was to observe the level of agreement on a single genre label per web page, and draw some conclusions about the appropriateness of limiting the assignment to only a single label when doing genre classification of web pages. Results show that users largely disagree on the label to be assigned to a web page.     

Windows环境下的多线程技术

多线程随着Ｗｉｎｄｏｗｓ环境的使用逐渐受到软件开发人员的重视,工作者线程和用户界面线程是Ｗｉｎｄｏｗｓ环境下的ＭＦＣ支持线程 的两个不同类型,文章论述了利用Ｗｉｎｄｏｗｓ环境下的ＶｉｓｕａｌＣ＋＋４．１实现上述两类线程的方法。     

一类平面五次Hamilton向量场的全局相图

本文利用微分方程定性理论 ,讨论了一类具有Z2 -等变性质的平面五次Hamilton向量场的全局性质 ,得到了其全局相图