适应用户兴趣变化的协同过滤增量更新机制

高维、稀疏的用户-项目评分矩阵对基于项目的协同过滤推荐算法造成严峻的可扩展性问题.传统的解决方法是离线计算项目相似性并保存在系统中以供算法调用,但是不能充分利用最新评分数据以体现用户兴趣的变化.针对上述问题,提出了适合在线应用的协同过滤项目相似性增量更新机制,使得推荐系统在当前用户提交项目评分之后,能够实时完成相应项目与其他项目之间的相似性数据更新,从而推荐系统可以基于最新的项目相似性数据进行推荐处理,以适应用户兴趣的变化.实验结果表明,本文提出的项目相似性增量更新机制能够有效提高基于项目的协同过滤算法可扩展性.     

基于聚类协同过滤的个性化推荐系统

个性化推荐系统被越来越多地应用到各类网站中,以解决信息增长带来的信息迷失和信息过栽问题,而协同过滤算法是个性化推荐系统的重要算法之一,但是传统的协同过滤算法存在数据稀疏、冷启动等问题,为了解决这些问题,在综合WEB日志挖掘和聚类两个因素基础上,提出基于WEB日志和聚类的协同过滤算法,并将该算法与传统的协同过滤算法进行分析比较,验证了该算法能够提高推荐的精确度和实时性．     

Social network data to alleviate cold-start in recommender system: A systematic review

Recommender Systems are currently highly relevant for helping users deal with the information overload they suffer from the large volume of data on the web, and automatically suggest the most appropriate items that meet users needs. However, in cases in which a user is new to Recommender System, the system cannot recommend items that are relevant to her/him because of lack of previous information about the user and/or the user-item rating history that helps to determine the users preferences. This problem is known as cold-start, which remains open because it does not have a final solution. Social networks have been employed as a good source of information to determine users preferences to mitigate the cold-start problem. This paper presents the results of a Systematic Literature Review on Collaborative Filtering-based Recommender System that uses social network data to mitigate the cold-start problem. This Systematic Literature Review compiled the papers published between 2011–2017, to select the most recent studies in the area. Each selected paper was evaluated and classified according to the depth which social networks used to mitigate the cold-start problem. The final results show that there are several publications that use the information of the social networks within the Recommender System; however, few research papers currently use this data to mitigate the cold-start problem.     

Nearest-biclusters collaborative filtering based on constant and coherent values

Collaborative Filtering (CF) Systems have been studied extensively for more than a decade to confront the “information overload” problem. Nearest-neighbor CF is based either on similarities between users or between items, to form a neighborhood of users or items, respectively. Recent research has tried to combine the two aforementioned approaches to improve effectiveness. Traditional clustering approaches (k-means or hierarchical clustering) has been also used to speed up the recommendation process. In this paper, we use biclustering to disclose this duality between users and items, by grouping them in both dimensions simultaneously. We propose a novel nearest-biclusters algorithm, which uses a new similarity measure that achieves partial matching of users’ preferences. We apply nearest-biclusters in combination with two different types of biclustering algorithms—Bimax and xMotif—for constant and coherent biclustering, respectively. Extensive performance evaluation results in three real-life data sets are provided, which show that the proposed method improves substantially the performance of the CF process.

软骨细胞图像的分割和测量

在软骨细胞自动分割计量系统的分割部分中，用Ostu法初步分割图像后，对轻度粘连细胞采用了形态滤波处理，利用细胞核信息进一步细化分割粘连较多的细胞，获得了较好的效果。     

Improving mobile learning with enhanced Shih＇s model of mobile learning

More recent motivational research focuses on the identification of effective techniques for enhancing instructional design and meeting the needs of diverse student populations （Wlodkowski R. J., 1981）. Learning-motivation researchers are applying some of the same theories and concepts found to be effective in industry to the development of motivational models that enhance the teaching-learning environment. One of such models is the Attention Relevance Confidence Satisfaction （ARCS） model of motivational design developed by John M. Keller （Small Ruth V., 2007）. The continuous improvement in handheld devices technologies has led to a new learning paradigm called mobile learning which involves the delivery of learning contents to learners utilizing mobile computing devices. Handheld devices, however, have constraints which limit their use for effective learning. Towards improving the effectiveness of mobile learning is a new mobile learning model proposed by Shih on which instructional designs for mobile learning can be based to facilitate mobile learning design and to achieve better mobile learning outcomes （Yushin E. Shih ＆ Dennis Mills, 2007）. Shih＇s model is based on Graphical User Interface （GUI）. This paper presents an enhanced Shih＇s model for effective mobile learning outcome in a university environment by making provision for instructional design to include online library search for both e-books and audio books using collaborative filtering algorithm to aid the search and posting and reading of testimonials about positive mobile learning outcomes so as to encourage other mobile learners. It also incorporates the use of Voice User Interface （VUI） to access the learning portal in order to overcome mobile devices interface limitations in addition to Graphical User Interface （GUI） proposed by Shih, so as to cater for the learning needs of the blind and the visually impaired.     

自适应回声消除器的设计与实现

介绍了回声消除器的基本结构、回声路径的脉冲响应以及语音信号的特点,分析输入信号为白噪声、有色噪声和语音的情况下自适应算法的性能,在此基础上应用一种参数筛选更新归一化最小均方差(NLMS)算法以及基于互相关的双边对话侦测算法,并提供详细仿真结果。     

基于CC的单输入三输出双二阶滤波结构

提出了一种电流模式多功能滤波结构。这种结构仅使用５个ＣＣ器件，３个接地电阻和两个接地电容。选择三具输出端中的一个或它们的组合即可实现五种基本的二阶滤波功能，元件灵敏度很低。比Ｓｅｎａｎｉ提出的结构简单。     

Contextual feature selection for text classification

We present a simple approach for the classification of “noisy” documents using bigrams and named entities. The approach combines conventional feature selection with a contextual approach to filter out passages around selected features. Originally designed for call for tender documents, the method can be useful for other web collections that also contain non-topical contents. Experiments are conducted on our in-house collection as well as on the 4-Universities data set, Reuters 21578 and 20 Newsgroups. We find a significant improvement on our collection and the 4-Universities data set (10.9% and 4.1%, respectively). Although the best results are obtained by combining bigrams and named entities, the impact of the latter is not found to be significant.     

网络安全之防火墙技术

网络防火墙技术在网络信息安全中的地位日趋重要，根据网络防火墙的分类及特点，分析常用防火墙的实现方法。