The need for reputation assessment is particularly strong in peer-to-peer (P2P) systems because the peers’ personal site autonomy is amplified by the inherent technological decentralization of the environment. However, the decentralization notion makes the problem of designing a P2P-based reputation assessment substantially harder in P2P networks than in centralized settings. Existing reputation systems tackle the reputation assessment process in an ad hoc manner. There is no systematic and coherent way to derive measures and analyze the current reputation systems. In this paper, we propose a reputation assessment process and use it to classify the existing reputation systems. Simulation experiments are conducted and focused on the different methods in selecting the recommendation sources and collecting the recommendations. These two phases can contribute significantly to the overall performance owing to precision, recall, and communication cost.

Building ontologies in a collaborative and increasingly community-driven fashion has become a central paradigm of modern ontology engineering. This understanding of ontologies and ontology engineering processes is the result of intensive theoretical and empirical research within the Semantic Web community, supported by technology developments such as Web 2.0. Over 6 years after the publication of the first methodology for collaborative ontology engineering, it is generally acknowledged that, in order to be useful, but also economically feasible, ontologies should be developed and maintained in a community-driven manner, with the help of fully-fledged environments providing dedicated support for collaboration and user participation. Wikis, and similar communication and collaboration platforms enabling ontology stakeholders to exchange ideas and discuss modeling decisions are probably the most important technological components of such environments. In addition, process-driven methodologies assist the ontology engineering team throughout the ontology life cycle, and provide empirically grounded best practices and guidelines for optimizing ontology development results in real-world projects. The goal of this article is to analyze the state of the art in the field of collaborative ontology engineering. We will survey several of the most outstanding methodologies, methods and techniques that have emerged in the last years, and present the most popular development environments, which can be utilized to carry out, or facilitate specific activities within the methodologies. A discussion of the open issues identified concludes the survey and provides a roadmap for future research and development in this lively and promising field.

The Web search has special characteristics against the desktop search when realized from mobile devices. To establish an improvement within this paradigm, an option is to take into account the context from which the search is developed. To conceptualize the mobile context, we propose the use of ontologies, which will include the device characteristics, environmental conditions and user preferences, among other term conceptualizations. This context definition would be used to determinate the behavior of a word recommendation when searching from mobile devices. As an essential process of creating this context ontology, we have made a real user's evaluation of the ontology terms by means of a survey. This paper shows a brief introduction to the project and focuses mainly on the results obtained in this concept's evaluation.

Video streaming over mobile wireless networks is getting popular in recent years. High video quality relies on large bandwidth provisioning, however, it decreases the number of supported users in wireless networks. Thus, effective bandwidth utilization becomes a crucial issue in wireless network as the bandwidth resource in wireless environment is precious and limited. The NGN quality of service mechanisms should be designed to reduce the impact of traffic burstiness on buffer management. For this reason, we propose an active dropping mechanism to deal with the effective bandwidth utilization in this paper. We use scalable video coding extension of H.264/AVC standard to provide different video quality for users of different levels. In the proposed dropping mechanism, when the network loading exceeds the threshold, the dropping mechanism starts to drop data of the enhancement layers for users of low service level. The dropping probability alters according to the change in network loading. With the dropping mechanism, the base station increases the system capability and users are able to obtain better service quality when the system is under heavy loading. We also design several methods to adjust the threshold value dynamically. By using the proposed mechanism, better quality can be provided when the network is in congestion.

As Web Services and the Semantic Web become more important, enabling technologies such as Web service ontologies will grow larger. At the same time, use of mobile devices to access Web services has doubled in the last year. The ability of these resource-constrained devices to download and reason across ontologies to support service discovery are severely limited. Since concrete agents typically only needs a subset of what is described in a Web service ontology to complete their task, a reduced ontology can be created. Measuring the quality of a reduced ontology, in both knowledge content and performance, is a nontrivial task. Expert analysis of the ontologies is time-consuming and unreliable. We propose two measures of knowledge content and performance. Mean average recall (MAR) with respect to the original ontology compares the data returned from a series of queries related to a particular concept of interest. Mean average performance (MAP) compares the download and reasoning speedup of the reduced ontology with respect to the original ontology. Neither of these values can be computed easily, therefore we propose a set of ontology metrics to predict these values. In this paper, we develop two prediction models for MAR and MAP based on these metrics. These models are based on analysis of 23 ontologies from five domains. To compute MAR, a specific set of queries for each domain was applied to each candidate reduced ontology along with the original ontology. To compute MAP, a simulated mobile device will download and process of each ontology along with the original ontology. We believe this model allows a speedy selection of a reduced ontology that contains the knowledge content and performance speedup needed by a mobile device for service discovery.

Agile software development (ASD) has emerged as a result of consolidated values proposed under the lightweight methods of software engineering. Despite bearing some criticisms, the initial deployment and results observed in the practice environment represents its increasing domination over the traditional software development practices. Any ASD method, in particular, requires knowledge-intensive practices and typically employs multi-disciplinary expert team working extended periods of time for weeks on a nearly continuous basis. A huge amount of tacit knowledge creation and exchange happens in the entire process over the project lifecycle, which attracts the attention of research in the domain of knowledge management (KM). In this paper, first, we have mapped the agile values and agile principles, and in its support, we have argued upon and the need for integrated KM infrastructure and proposed a KM model that can be employed within the organization. We have also developed a conceptual framework for knowledge sharing and learning for the individual practitioners for the sustainability of agile team. We attempt to create an organizational learning framework for knowledge creation and exchange among the involved entities in a collaborative practice environment.

Traditional Route Search aims at finding the path that goes through geographical entities that are relevant to the provided search terms from the start point to the end point. Without constraints, traditional Route Search visiting multiple locations is unreliable because locations may close after a specified time. In this paper, time constraint (operating hours of each location) is drawn into Route Search query in order to make the query more realistic. Two methods are proposed in this paper, namely Route Search for fixed locations (RFix) and Route Search for flexible locations (RFlex). These two queries are different from the existing Route Search query because (1) the end point is not pre-defined and (2) time constraint is involved. Our two proposal queries consider whether the locations are specifically pre-defined by the user or only the location types are specified. In each method, two propositions are presented for pruning expansion branches, which highly improves the performance. Our experiments verified the applicability of RFix and RFlex to solve Route Search queries with time constraint queries.

Information services facilitate users to exploit applications over the network and access them from the remote system at the client side. In this paper, we describe the design and development of information services for novelty mining, which allows users to access the novel yet relevant information of a given topic. Several methodologies regarding novelty mining such as novelty scoring, novelty threshold, novelty feedback, and document-to-sentence technique are described. In addition to Web services, mobile information services are also described. Modelling and implementing information services for novelty mining are especially useful for users to reduce their information overload. We describe the challenging issue of decomposing the complex novelty mining application into several smaller and simpler modules, which are later implemented as services on the Web as well as mobile devices. After deploying our information services for novelty mining, test cases are provided to demonstrate the system. Our information services for novelty mining are confirmed to be helpful in increasing the efficiency of enterprise users in gathering novel information from incoming text. By studying the design and development of information services for novelty mining, we can benefit other developers in investigating effective techniques for developing enterprise services for other real-world applications.

Lack of sufficient semantic description in the content of Web services makes it difficult to find and compose suitable Web services during analysis, search, and matching processes. Semantic Web Services are Web services that have been enhanced with formal semantic description, which provides well-defined meaning. Due to insertion of semantics, meeting user demands will be made possible through logical deductions achieving resolutions automatically. We have developed an inference-based semantic business process composition agent (SCA) that employs inference techniques. The semantic composition agent system is responsible for the synthesis of new services from existing ones in a semi-automatic fashion. SCA System composes available Web Ontology Language for Web services atomic processes utilizing Revised Armstrong's Axioms (RAAs) in inferring functional dependencies. RAAs are embedded in the knowledge base ontologies of SCA System. Experiments show that the proposed SCA System produces process sequences as a composition plan that satisfies user's requirement for a complex task. The novelty of the SCA System is that for the first time Armstrong's Axioms are revised and used for semantic-based planning and inferencing of Web services.

This paper discusses a goal-based approach for the engineering of capacity-driven Web services. In this approach, goals are established to first, define the roles that these Web services will play in implementing business applications, second, frame the requirements that will be put on these Web services, and third, identify the processes in terms of business logics that these Web services will carry out. Because of the nature of capacity-driven Web services compared with regular (i.e. mono-capacity) Web services, their engineering in terms of design, development, and deployment takes place in a different way. A Web service that is empowered with several capacities, which are basically separate groups of operations to execute, has to choose one capacity for triggering at run-time. To this end, the Web service takes into account different types of requirements like data and privacy that are put on each capacity that empowers this Web service.