基于性能感知预测的云服务推荐模型

互联网上出现越来越多的云服务,面对种类繁多的云服务,如何准确地在众多云服务中把符合用户需求并且性能好价格低的服务推荐给用户成为云服务推荐的研究热点.现有的服务推荐方法往往只是根据当前云服务的历史性能记录为用户进行推荐,并没有充分考虑云服务的性能趋势.针对上述问题,本文提出了一种基于性能预测的服务推荐模型,该模型利用共轭梯度改进人工神经网络对云服务的性能进行预测,使用层次分析法对性能,价格等因素进行综合比较计算,最终为用户推荐最为合适的云服务.实验结果表明,使用改进神经网络对服务性能进行预测能够获得较高的准确度,层次分析法可以综合考虑服务的性能与价格,为用户推荐最为合适的云服务.     

基于用户空间位置评分云模型的Web服务协同过滤推荐算法

Web服务作为无形的产品,不具备真实环境下的空间地理位置坐标,针对服务推荐中无法衡量用户群体与Web服务之间的距离位置关系,造成用户相似度计算失衡,导致推荐不准确等问题,提出了基于用户空间位置评分云模型的Web服务协同过滤推荐算法.首先基于用户群体的行为数据量化Web服务的热度区域,通过空间位置量化评分描述用户对于Web服务的兴趣偏好;其次利用云模型来描述每个用户空间行为评分的整体特征,设计了云模型间相似贴近度的计算方法,基于该方法提出了一种用户差异程度系数评估算法,并作为调控系数优化了皮尔森相似度量;最后通过协同过滤找出用户感兴趣的Web服务.实验结果表明该算法使得用户行为偏好的区域划分更加精确,在推荐准确率上明显提高,为基于位置的Web服务推荐提供新颖的方案.     

Recommend trustworthy services using interval numbers of four parameters via cloud model for potential users

How to discover the trustworthy services is a challenge for potential users because of the deficiency of usage experiences and the information overload of QoE (quality of experience) evaluations from consumers. Aiming to the limitations of traditional interval numbers in measuring the trustworthiness of service, this paper proposed a novel service recommendation approach using the interval numbers of four parameters (INF) for potential users. In this approach, a trustworthiness cloud model was established to identify the eigenvalue of INF via backward cloud generator, and a new formula of INF possibility degree based on geometrical analysis was presented to ensure the high calculation precision. In order to select the highly valuable QoE evaluations, the similarity of client-side feature between potential user and consumers was calculated, and the multi-attributes trustworthiness values were aggregated into INF by the fuzzy analytic hierarchy process method. On the basis of ranking INF, the sort values of trustworthiness of candidate services were obtained, and the trustworthy services were chosen to recommend to potential user. The experiments based on a realworld dataset showed that it can improve the recommendation accuracy of trustworthy services compared to other approaches, which contributes to solving cold start and information overload problem in service recommendation.     

基于凸函数证据理论的关联感知云服务信任模型

针对大规模分布式云计算系统中的服务可信度辨别问题,提出一种基于凸函数证据理论的关联感知云服务信任模型。对云计算系统中云服务提供商、服务和用户之间的信任关系进行形式化描述,充分挖掘了同一服务商中的不同云服务之间的关联性,利用凸函数证据理论对有序命题的处理能力,构建了云计算系统中的可信服务推荐方法,根据用户需求为其提供合理可靠的云服务。与经典证据理论方法的对比结果表明,基于凸函数证据理论的关联感知云服务信任模型在保证有效性和健壮性的同时,充分利用了云计算系统中云服务之间的关联信息,能够根据用户的请求提供合理的云服务。     

Collaborative filtering based on collaborative tagging for enhancing the quality of recommendation

We propose a collaborative filtering method to provide an enhanced recommendation quality derived from user-created tags. Collaborative tagging is employed as an approach in order to grasp and filter users’ preferences for items. In addition, we explore several advantages of collaborative tagging for data sparseness and a cold-start user. These applications are notable challenges in collaborative filtering. We present empirical experiments using a real dataset from del.icio.us. Experimental results show that the proposed algorithm offers significant advantages both in terms of improving the recommendation quality for sparse data and in dealing with cold-start users as compared to existing work.     

基于云模型的项目评分预测推荐算法

针对用户评分数据的极端稀疏性和传统计算项目相似性方法存在的弊端,提出一种基于云模型的推荐算法,利用云模型计算项目间的相似度来预测用户对未评分项目的评分,再通过云模型计算用户间的相似度,得到目标用户的最近邻居。实验结果表明,该算法不仅能有效解决用户评分数据的稀疏性问题,还能提高推荐系统的推荐质量。     

一种融合个性化与多样性的人物标签推荐方法

针对人物标签推荐中多样性及推荐标签质量问题,该文提出了一种融合个性化与多样性的人物标签推荐方法。该方法使用主题模型对用户关注对象建模,通过聚类分析把具有相似言论的对象划分到同一类簇;然后对每个类簇的标签进行冗余处理,并选取代表性标签;最后对不同类簇中的标签融合排序,以获取Top-K个标签推荐给用户。实验结果表明,与已有推荐方法相比,该方法在反映用户兴趣爱好的同时,能显著提高标签推荐质量和推荐结果的多样性。     

一种新的数字图书馆云服务用户满意度模型

随着云计算技术的发展,数字图书馆云服务评价成为迫切需要解决的问题.基于层次分析法(AHP),设计一种新的用户满意度模型评估数字图书馆云服务;为了从评估者角度获得测评指标的相对重要程度,提出一种新的AHP算法判断矩阵构造方式.实例表明:1)用户满意度模型能准确定位评估人员迫切需要改进的数字图书馆云服务; 2)改进的AHP算法能够从评估人员角度获得测评指标的权重值,有助于提高用户满意度的准确性.     

An OWA‐Based Ranking Approach for University Books Recommendation

Generally the book recommendation approaches are personalized in nature, that is, they utilize the users’ purchasing behavior to recommend them the book similar to their preferences. The main problem with the personalized recommendation is its knowledge requirement about users’ past preferences. As a result, these techniques fail in producing appropriate recommendation for a new user whose preferences are not known. The personalized recommendation also needs extra space to store the users’ preferences. In this paper, a framework to recommend books to university students for their studies is presented. In order to answer which books are to be included in the syllabus, a specialized way of recommendation, where recommendations from experts of the subjects at different universities are considered, is presented. We have suggested a ranked recommendation approach for books, which employ Ordered Weighted Aggregation (OWA), a fuzzy‐based aggregation, to aggregate the several ranking of the top universities. On the one hand, it does not need user prior preferences, and on the other hand, it eases the complexities of personalized recommendation to huge number of users and replaces it with a single ranked recommendation. The experimental results are compared with the existing positional aggregation algorithm that demonstrates significant improvement in the results with respect to various performance metrics.     

三网融合下图书云服务个性化推荐

随着云计算技术的飞速发展,数字图书馆云平台 SaaS 层的图书应用服务数量将会快速增长,为图书用户选择个性化的云服务带来困难。通过建立偏好树,构建了三网融合环境下的图书用户模型和图书云服务模型。为了确定图书云服务对图书用户的推荐度,设计了服务选择算法。经过实验数据分析,该算法可以根据图书用户模型的偏好需求,为用户推荐匹配度较高的图书云服务。     

Policing as a Service in the Cloud

ABSTRACT

Security and privacy are fundamental concerns in cloud computing both in terms of legal complications and user trust. Cloud computing is a new computing paradigm, aiming to provide reliable, customized, and guaranteed computing dynamic environment for end users. However, the existing security and privacy issues in the cloud still present a strong barrier for users to adopt cloud computing solutions. This paper investigates the security and privacy challenges in cloud computing in order to explore methods that improve the users’ trust in the adaptation of the cloud. Policing as a Service can be offered by the cloud providers with the intention of empowering users to monitor and guard their assets in the cloud. This service is beneficial both to the cloud providers and the users. However, at first, the cloud providers may only be able to offer basic auditing services due to undeveloped tools and applications. Similar to other services delivered in the cloud, users can purchase this service to gain some control over their data. The subservices of the proposed service can be Privacy as a Service and Forensics as a Service. These services give users a sense of transparency and control over their data in the cloud while better security and privacy safeguards are sought.     

Cloud Service Recommendation Based on a Correlated QoS Ranking Prediction

Quality-of-Service (QoS) is an important concept for service selection and user satisfaction in cloud computing. So far, service recommendation in the cloud is done by means of QoS, ranking and rating techniques. The ranking methods perform much better, when compared with the rating methods. In view of the fact that the ranking methods directly predict QoS rankings as accurately as possible, in most of the ranking methods, an individual QoS value alone is employed to predict the cloud rank. In this paper, we propose a correlated QoS ranking algorithm along with a data smoothing technique and combined with QoS to predict a personalized ranking for service selection by an active user. Experiments are conducted employing a WSDream-QoS dataset, including 300 distributed users and 500 real world web services all over the world. Six different techniques of correlated QoS ranking schemes have been proposed and evaluated. The experimental results showed that this approach improves the accuracy of ranking prediction when compared to a ranking prediction framework using a single QoS parameter.     

基于市场机制的云服务管理研究

云计算以其几乎无限的计算能力、存储能力和带宽,成为很多企业和组织研究和使用的最佳选择。为了实现云服务的商业化,云市场的出现是必要的。由于云市场中出现的服务类型和数量日益增加,如何帮助用户选择合适的提供商是个很大的挑战。文中提出一个以云市场为基础的机制,并给出一个推荐系统来管理云服务。该管理机制一定程度上节省了用户和供应商选择交易对象的时间,并且能够很好地满足用户的服务要求和预算成本,提高了整个云市场的效率。     

混合云中的一个高效协调器

云计算提供了4种部署模型:公有云、私有云、社区云和混合云.通常,一个私有云中可用的资源是有限的,因此云用户不得不从公有云租用资源.这意味着云用户将会产生额外的费用.越来越多的企业选择混合云来部署它们的应用.在混合云中,为了实现用户的利益最大化,必须满足使用资源的费用最小化和用户的QoS,为此为混合云用户提供了一个既能最小化资源费用又能保证满足QoS的资源分配方法.实验结果表明,该算法在保持低操作成本的同时还满足了用户的QoS.     

Tag recommendation method in folksonomy based on user tagging status

A folksonomy consists of three basic entities, namely users, tags and resources. This kind of social tagging system is a good way to index information, facilitate searches and navigate resources. The main objective of this paper is to present a novel method to improve the quality of tag recommendation. According to the statistical analysis, we find that the total number of tags used by a user changes over time in a social tagging system. Thus, this paper introduces the concept of user tagging status, namely the growing status, the mature status and the dormant status. Then, the determining user tagging status algorithm is presented considering a user’s current tagging status to be one of the three tagging status at one point. Finally, three corresponding strategies are developed to compute the tag probability distribution based on the statistical language model in order to recommend tags most likely to be used by users. Experimental results show that the proposed method is better than the compared methods at the accuracy of tag recommendation.     

云计算环境下的弹性结构程序研究

针对云计算环境下云程序的弹性结构进行研究,结合Anytime算法、弹性计价模型和软件即服务层中的SLA计费架构,将总业务费用分为接入费用、使用费用和补偿费用进行计算,设计基于图像小波变换的弹性结构程序,给出程序的执行步骤和状态转换图。分析结果表明,该弹性结构程序能对程序迭代次数进行控制,较好满足用户需求。     

Semantic trajectory-based high utility item recommendation system

The topic on recommendation systems for mobile users has attracted a lot of attentions in recent years. However, most of the existing recommendation techniques were developed based only on geographic features of mobile users’ trajectories. In this paper, we propose a novel approach for recommending items for mobile users based on both the geographic and semantic features of users’ trajectories. The core idea of our recommendation system is based on a novel cluster-based location prediction strategy, namely TrajUtiRec, to improve items recommendation model. Our proposed cluster-based location prediction strategy evaluates the next location of a mobile user based on the frequent behaviors of similar users in the same cluster determined by analyzing users’ common behaviors in semantic trajectories. For each location, high utility itemset mining algorithm is performed for discovering high utility itemset. Accordingly, we can recommend the high utility itemset which is related to the location the user might visit. Through a comprehensive evaluation by experiments, our proposal is shown to deliver excellent performance.     

基于隐性反馈的自适应推荐系统研究

介绍个性化自适应推荐系统的整体架构与设计方法。阐述用户兴趣模型的建立,包括对用户个性化信息的收集、精炼处理、模糊语意处理、解模糊化及满意度计算。引入模糊自适应共振理论网络进行项目聚类分析,并进行推荐处理,实现自适应推荐服务。实验结果表明,系统对用户兴趣判断比较准确,能及时掌握用户兴趣偏移,推荐效果良好,且基本稳定。     

情景感知的物联网服务推荐方法研究

如何根据用户实时的情景高效地为其推荐最为合适的物联网服务,已经成为当前服务计算与物联网领域亟需解决的关键问题之一。针对这一问题,提出了一种基于情景感知的物联网服务推荐方法。首先基于改进的FolkRank算法生成当前用户可用的物联网服务列表;之后,依据用户当前关键的情景构建用户情景信息模型,根据用户的情景模型从服务列表中筛选出最能满足用户当前情景的物联网服务。实验结果表明,所提出的情景感知的物联网服务推荐方法是可行的与有效的。     

基于加权三部图的协同过滤推荐算法

针对基于用户的协同过滤算法推荐结果过度集中在热门物品,导致多样性和新颖性较低、覆盖率较小的问题,文中提出基于加权三部图的协同过滤推荐算法.在分析数据稀疏和附加信息较少的基础上引入标签信息,可同时反映用户兴趣和物品属性,利用用户、物品和标签三元关系构建三部图.通过三部图网络映射到单模网络的方法获得用户偏好度,构建用户偏好度加权的三部图模型.根据热传导方法在加权三部图上进行资源重分配,挖掘更多的相似关系,利用协同过滤框架预测评分并进行推荐.在真实数据集上的实验表明,文中算法可较好地挖掘长尾物品,实现个性化推荐.