In modern distributed systems, service consumers are faced with pools of service providers that offer similar functionalities. This reality renders the selection of web services a challenging task. One popular solution is to base the selection decisions on the web services’ non-functional requirements depicted by a variety of QoS metrics. In this paper, we present a new approach for solving the web service selection problem; a QoS-aware trust model that leverages the correlation information among various QoS metrics. This model, based on the probability theory, estimates the trustworthiness of web services by exploiting two statistical distributions, namely, Dirichlet and generalized Dirichlet. These distributions represent the outcomes of multiple correlated QoS metrics. The former distribution is employed when the QoS metrics are positively correlated while the latter handles negatively correlated metrics. We also propose an algorithm to aggregate reputation feedback that propagate among the interacting web services. This algorithm deals with malicious feedback and various strategic behavior commonly performed by web services. Experimental results endorse the advantageous capability of our trust model and reputation algorithm compared to the state-of-the-art.

Wikipedia may be the best‐developed attempt thus far to gather all human knowledge in one place. Its accomplishments in this regard have made it a point of inquiry for researchers from different fields of knowledge. A decade of research has thrown light on many aspects of the Wikipedia community, its processes, and its content. However, due to the variety of fields inquiring about Wikipedia and the limited synthesis of the extensive research, there is little consensus on many aspects of Wikipedia's content as an encyclopedic collection of human knowledge. This study addresses the issue by systematically reviewing 110 peer‐reviewed publications on Wikipedia content, summarizing the current findings, and highlighting the major research trends. Two major streams of research are identified: the quality of Wikipedia content (including comprehensiveness, currency, readability, and reliability) and the size of Wikipedia. Moreover, we present the key research trends in terms of the domains of inquiry, research design, data source, and data gathering methods. This review synthesizes scholarly understanding of Wikipedia content and paves the way for future studies.

Hundreds of scholarly studies have investigated various aspects of Wikipedia. Although a number of literature reviews have provided overviews of this vast body of research, none has specifically focused on the readers of Wikipedia and issues concerning its readership. In this systematic literature review, we review 99 studies to synthesize current knowledge regarding the readership of Wikipedia and provide an analysis of research methods employed. The scholarly research has found that Wikipedia is popular not only for lighter topics such as entertainment but also for more serious topics such as health and legal information. Scholars, librarians, and students are common users, and Wikipedia provides a unique opportunity for educating students in digital literacy. We conclude with a summary of key findings, implications for researchers, and implications for the Wikipedia community.

Service oriented computing is being increasingly exploited in the architecture of current web applications. The interactions among the deployed web services are becoming vital to accomplish heterogeneous and compound business goals. Service selection and composition are two common tasks which are highly influenced by the quality of these interactions. Thus, assigning web services QoS-based trust scores that are incrementally updated, provides a means to assist both tasks. Then, services with higher trust scores are more likely to be selected than those with smaller ones. They are, additionally, more prone to be incorporated as part of composite services. In this paper, we propose a probabilistic approach based on Bayesian networks (BN) to learn the composition structure of composite services and compute QoS-based trust scores in an online setting. The learning of the BN structure and parameters is based on modeling the QoS, which is represented by the BN's variables, using a multinomial generalized Dirichlet distribution (MGDD). The effectiveness of our approaches is empirically assessed using real and synthetic data. Our experimental results show that MGDD provides a flexible and accurate representation of the QoS. They also prove the capability of the BN approach to learn the composition structure, and further the responsibility of the constituent services in the quality of the composite service even when their QoS is partially observed.

Software architectures of large-scale systems are perceptibly shifting towards employing open and distributed computing. Service Oriented Computing (SOC) is a typical example of such environment in which the quality of interactions amongst software agents is a critical concern. Agent-based web services in open and distributed architectures need to interact with each other to achieve their goals and fulfill complex user requests. Two common tasks are influenced by the quality of interactions among web services: the selection and composition. Thus, to ensure the maximum gain in both tasks, it is essential for each agent-based web service to maintain a model of its environment. This model then provides a means for a web service to predict the quality of future interactions with its peers. In this paper, we formulate this model as a machine learning problem which we analyze by modeling the trustworthiness of web services using probabilistic models. We propose two approaches for trust learning of single and composed services; Bayesian Networks and Mixture of Multinomial Dirichlet Distributions (MMDD). The effectiveness of our approaches is empirically assessed using a simulation study. Our results show that representing the quality of a web service by Multinomial Dirichlet Distribution (MDD) provides high flexibility and accuracy in modeling trust. They also show that using our approaches to estimate trust enhances web services selection and composition.