Bøger af Gian P. Picco

Recent years have witnessed the appearance of new paradigms for designing distributed applications where the application components can be relocated - namically across the hosts of the network. This form of code mobility lays the foundation for a new generation of technologies, architectures, models, and - plications in which the location at which the code is executed comes under the control of the designer, rather than simply being a con?guration accident. Among the various ?avors of mobile code, the mobile agent paradigm has become particularly popular. Mobile agents are programs able to determine - tonomously their own migration to a di?erent host, and still retain their code and state (or at least a portion thereof). Thus, distributed computations do not necessarily unfold as a sequence of requests and replies between clients and - mote servers, rather they encompass one or more visits of one or more mobile agents to the nodes involved. Mobile code and mobile agents hold the potential to shape the next gene- tion of technologies and models for distributed computation. The ?rst steps of this process are already evident today: Web applets provide a case for the least sophisticated form of mobile code, Java-based distributed middleware makes - creasing use of mobile code, and the ?rst commercial applications using mobile agents are starting to appear.

This book constitutes the refereed proceedings of the two thematic workshops held jointly with Networking 2002: WEB Engineering and Peer-to-Peer C- puting. Networking 2002 was organized by the Italian National Research Council (CNR) and was sponsored by the IFIP working groups WG 6.2 (Network and Intern- work Architectures), WG 6.3 (Performance of Communication Systems), and WG 6.8 (Wireless Communications). The program of the conference covered ?ve days and included the main conference (three days), two tutorial days, and one day of thematic workshops. TheInternationalWorkshoponWebEngineeringwasdedicatedtothedisc- sionoftheprincipalissuesthatemergeinthedesignandimplementationoflar- scale, complex, Web-based systems. Scalability issues pose a number of ch- lenging problems to solve for both applications and the underlying web/network infrastructure. On one hand, web services and internet applications must take into account network performance and transport protocol design, to achieve - ceptable performance and robustness. On the other hand, emerging network and Web technologies are determined by the requirements of these applications. Fifteen papers were presented that illustrated the current state of the art in this area. In addition to the authors of these papers, the Workshop on Web Engine- ing was attended by about thirty participants, who contributed to the workshop by stimulating fruitful discussions at the end of each presentation. Thus, this workshop provided a excellent opportunity for researchers, from both industry and academia, to gather, exchange ideas, and discuss recent results in the dev- opment of Web-based systems and emerging Internet applications.