A schema-based P2P network to enable publish-subscribe for multimedia content in open hypermedia systems

Open Hypermedia Systems (OHS) aim to provide efficient dissemination, adaptation and integration of hyperlinked multimedia resources. Content available in Peer-to-Peer (P2P) networks could add significant value to OHS provided that challenges for efficient discovery and prompt delivery of rich and up-to-date content are successfully addressed. This paper proposes an architecture that enables the operation of OHS over a P2P overlay network of OHS servers based on semantic annotation of (a) peer OHS servers and of (b) multimedia resources that can be obtained through the link services of the OHS. The architecture provides efficient resource discovery. Semantic query-based subscriptions over this P2P network can enable access to up-to-date content, while caching at certain peers enables prompt delivery of multimedia content. Advanced query resolution techniques are employed to match different parts of subscription queries (subqueries). These subscriptions can be shared among different interested peers, thus increasing the efficiency of multimedia content dissemination

Inter-destination Multimedia Synchronization: A Contemporary Survey

The advent of social networking applications, media streaming technologies, and synchronous communications has created an evolution towards dynamic shared media experiences. In this new model, geographically distributed groups of users can be immersed in a common virtual networked environment in which they can interact and collaborate in real- time within the context of simultaneous media content consumption. In this environment, intra-stream and inter-stream synchronization techniques are used inside the consumers’ playout devices, while synchronization of media streams across multiple separated locations is required. This synchronization is nown as multipoint, group or Inter-Destination Multimedia Synchronization (IDMS) and is needed in many applications such as social TV and synchronous e-learning. This survey paper discusses intraand inter-stream synchronization issues, but it mainly focuses on the most well-known IDMS techniques that can be used in emerging distributed multimedia applications. In addition, it provides some research directions for future work

The Advent of Semantic Web in Tourism Information Systems

The tourism industry depends on complex value creation chains involving a large number of participants that change frequently and rapidly. In addition, the products of tourism industry are complex and they will perish if they are not sold in time. For these reasons, the ideal tourism information systems require a lot of flexibility of underlying systems. Moreover, they comprise accurate access to any tourism service that provide, and they are usable by corporate and private customers alike. The management and interoperation of semantically diverse tourism information systems are facilitated by Semantic Web technology that provides methods and standards, which allow accurate access to information as well as flexibility to comply with needs of tourism information system users and administrators. This paper considers state-of-the art issues (ontologies, semantic modelling and querying, semantic portals and semantic-based e-markets) concerning the exploitation of the semantic web technologies and applications in tourism information systems

The Advent of Semantic Web in Tourism Information Systems

The tourism industry depends on complex value creation chains involving a large number of participants that change frequently and rapidly. In addition, the products of tourism industry are complex and they will perish if they are not sold in time. For these reasons, the ideal tourism information systems require a lot of flexibility of underlying systems. Moreover, they comprise accurate access to any tourism service that provide, and they are usable by corporate and private customers alike. The management and interoperation of semantically diverse tourism information systems are facilitated by Semantic Web technology that provides methods and standards, which allow accurate access to information as well as flexibility to comply with needs of tourism information system users and administrators. This paper considers state-of-the art issues (ontologies, semantic modelling and querying, semantic portals and semantic-based e-markets) concerning the exploitation of the semantic web technologies and applications in tourism information systems

Low Cost Inferential Forecasting and Tourism Demand in Accommodation Industry

This paper establishes a low cost inferential model that allows reliable time series forecasts. The model provides a naive unique computationally straightforward approach based on widely-used additive models. It refers to the decomposition of every time series value in “random” components, which are compounded to constitute a “Fibonacci type” predictor random variable. The expected value of this predictor gives a forecast of a future time series value. The standard deviation of the predictor serves to construct a prediction interval at a predefined confidence level. The major features of our model are: forecasting accuracy, simplicity of the implementation technique, generic usefulness, and extremely low cost effort. These features enable our model to be adopted by tourism practitioners on various types of forecasting demands. In this paper, we present an application study to forecast tourism demand that exists in the Greek accommodation industry (i.e. in Greece and in the broad region of Athens). In the application study, two independent approaches have been adopted. In the first approach we implemented our model, and in the second approach we implemented the well-known Box-Jenkins method

On the price of stability of some simple graph-based hedonic games

We consider graph-based hedonic games such as simple symmetric fractional hedonic games and social distance games, where a group of utility maximizing players have hedonic preferences over the players’ set, and wish to be partitioned into clusters so that they are grouped together with players they prefer. The players are nodes in a connected graph and their preferences are defined so that shorter graph distance implies higher preference. We are interested in Nash equilibria of such games, where no player has an incentive to unilaterally deviate to another cluster, and we focus on the notion of the price of stability. We present new and improved bounds on the price of stability for several graph classes, as well as for a slightly modified utility function

Code Quality Evaluation Methodology Using The ISO/IEC 9126 Standard

This work proposes a methodology for source code quality and static behaviour evaluation of a software system, based on the standard ISO/IEC-9126. It uses elements automatically derived from source code enhanced with expert knowledge in the form of quality characteristic rankings, allowing software engineers to assign weights to source code attributes. It is flexible in terms of the set of metrics and source code attributes employed, even in terms of the ISO/IEC-9126 characteristics to be assessed. We applied the methodology to two case studies, involving five open source and one proprietary system. Results demonstrated that the methodology can capture software quality trends and express expert perceptions concerning system quality in a quantitative and systematic manner.Comment: 20 pages, 14 figure