Giovanni Cortese

Model-driven Composition of Context-aware Web Services Using ContextUML and Aspects

Service oriented architectures (SOAs) are constantly gaining ground for the provision of business to business as well as user-centric services, mainly in the form of Web services technology. SOAs enable service providers to design and deploy new,composite service offerings out of existing component services. In order to match end-user expectations with respect to personalization and ease of use, these services should be designed in a manner that allows them to exhibit a certain level of context-awareness which is a basic element towards a richer end-user experience. However, in the majority of such services, context-handling is still tightly coupled with the core functionality of the service, resulting in a design which is difficult to implement and maintain. The paper proposes the decoupling of core service logic from context-related functionality by adopting a model-driven approach based on a modified version of the ContextUML metamodel. Core service logic and context handling are treated as separate concerns at the modeling level as well as in the resulting source code where aspect oriented programming (AOP) encapsulates context-dependent behavior in discrete code modules. The design of a restaurant finder service is used to portray the modified ContextUML metamodel and the service modeling process which is covered in full. Respective code snippets belonging to the executable version of the service (part of work in progress) are also provided, illustrating the transition from model to code and the resulting separation of concerns.

SMS: Simplifying Mobile Services - for Users and Service Providers

To date, mobile services have failed to match the explosive growth of the World Wide Web. This, we argue, is because current services are difficult to use, design and deploy. In this paper we describe a concept for a new class of services, addressing these issues. We call these services Simple Mobile Services (SMS). SMS will be simple for users to find, use, and trust; similarly they will be simple for providers to develop and deploy. Like the Web, they will provide technology and operator-independent end-to-end connectivity. But unlike conventional Web-based services they will target specific locations of interest to specific classes of mobile user with specific needs. We propose a design methodology and a set of related tools for the creation of SMS - based on the Model Driven Architecture (MDA) approach. We show how this methodology can support the design and deployment of SMS by service providers with limited technical expertise.

Flexible Java real-time profile for business-critical systems

Despite Javas initial promise of providing a reliable and cost-effective platform-independent environment, the language appears to be unfavourable in the area of distributed soft real-time systems. To address this issue, the language environment must provide not only a well-defined specification or subset, but also a complete environment with appropriate analysis tools. This paper describes an architecturally neutral real-time framework, which is proposed by the HIJA (High-Integrity Java Applications) project, for distributed soft real-time systems with analysis tools. The framework includes, among other features, a proper language profile, QoS (Quality of Service) and resource management, component-based system development and RMI based communication.

A Novel Approach to Adaptive Content-based Subscription Management in DHT-based Overlay Networks

Content-based Publish/Subscribe (CBPS) interaction paradigm is suitable for a variety of large scale dynamic applications: News delivery, stock quoting, air and metropolitan traffic control, on-line games, dissemination of multimedia contents, dissemination of auction bids, services and resources discovery, remote control of critical infrastructures and management of large scale systems. In contrast to their flexibility and expressiveness scalable CBPS systems are difficult to implement and the proposed solutions are not again mature. In this paper we propose a novel adaptive content-based subscription management system, relying on a Distributed Hash Table routing infrastructure. We define a model for the event space guaranteeing the expressiveness for any application domain. Also we provide mechanism to dynamically identify groups of users with similar preferences (multicast group). Two different approaches for multicast group identification are proposed and discussed: A dummy regular Grid partitioning of the event space and a more complex clustering of users preferences. When system evolves (e.g. joining and leaving of publisher and subscriber and/or nodes failure) multicast groups are reconfigured to maintain the desired level of system efficiency. System adaptation is supported by a scalable and dynamic application-level multicast infrastructure, and by a run time performance measurement mechanism. The paper gives a formal description of our solution and the main design guidelines. Also we discuss advantages and disadvantages of our proposal, compared with the existing solutions.

Challenges in communications research beyond the VICOM project

The VICOM (Virtual Immersive COMmunications) project is a three-year project funded by the Italian Ministry of Instruction University and Research aiming at investigating innovative communication paradigms. The project represents a wide coordinated effort focused on integration of immersive and wireless technologies in view of the fourth generation of mobile communications. The main goal of the project consists of the design of a wideband system architecture for immersive services and of its validation through two distributed large test-beds. Starting from VICOM ongoing experiences some future challenges and objectives for the future situated and autonomic communications technologies are envisaged in the paper.

Building Customizable Frameworks for the Telecommunications Domain: A Comparison of Approaches

Based on the experience of development of industrial application frameworks for the telecommunications domain, we compare different approaches and techniques for achieving software reuse. In particular, we describe an assessment we performed on two application frameworks for the telecommunications domain developed in Sodalia. The assessment had the objective of collecting evidence on the benefits and implications of different techniques which can be adopted for achieving large-grain reuse in product line development.

Architectures For Context Aware Services

In this paper, we describe our application framework (Multi-Site Navigator) for delivering context-aware services. The application framework is based on our middleware solution, named context Data Manager (XDM), using DHTs technologies as underlying substrate for integrating different contextual data generators or sensors.