Abstracts of the ECOOP'96 Workshop on Mobile Object Systems


A Characterization of Mobility and State Distribution in Mobile Code Languages

Gianpaolo Cugola, Carlo Ghezzi, Gian Pietro Picco and Giovanni Vigna

The growing importance of telecommunication networks has stimulated research on a new generation of programming languages. Such languages view the network and its resources as a global environment in which computations take place. In particular, they support the notion of code mobility and state distribution. To understand, discuss, evaluate, and compare such languages, it is necessary to develop an abstract model that allows the meaning of mobility and state distribution to be defined precisely. The purpose of this paper is to provide such a model and to apply it to the analysis of a number of existing new languages.

Protected and Secure Mobile Object Computing in PLANET

Kazuhiko Kato, Kunihiko Toumura, Katsuya Matsubara, Susumu Aikawa, Jun Yoshida, Kenji Kono, Kenjiro Taura and Tatsurou Sekiguchi

Worldwide networks such as the Internet are becoming very popular, so distributed computing environments for such networks are in high demand. We think the design of such an environment should be based on a mobile-object computing model and are therefore designing a mobile-object system called Planet. One of the most significant issues in designing mobile object systems for world-wide networks is to provide the control needed to assure the protection and security of mobile objects and of computing resources. In this paper we describe our approach to this issue.

Mole - A Java Based Mobile Agent System

Markus Straßer, Joachim Baumann and Fritz Hohl

Mobile agents are active, autonomous objects, which are able to move between locations in a so-called agent system, a distributed abstraction layer providing security of the underlying systems on one hand and the concepts and mechanisms for mobility and communication on the other hand. In this paper, the mobility, the communication concepts and the architecture of Mole, an agent system developed at the University of Stuttgart, are presented.

Combining Mobile Agents with Persistent Systems: Opportunities and Challenges

Miguel Mira da Silva and Malcolm Atkinson

In the last three years we have been working with persistence and distribution, in particular migration of higher-level objects (such as procedures) between autonomous persistent programs. In this paper we introduce persistence and the suitability of Napier88, the persistent system we have used for our experiments, as an agent language. We then present a few examples of opportunities and many more challenges that exist in the combination of persistence with agents.

Secure Object Spaces

Jan Vitek

Mobile software agents are computational entities acting on the behalf of a user which may move from computer to computer over a heterogeneous network, draw on local resources, and interact with other agents. This extended abstract discusses agent communication and its implications for security.

Designing agents for archie and ftp sessions in Obliq

Cristian Ionitoiu

This extended abstract presents a solution based on mobile agents for archie/ftp sessions on Internet. Due to the increased rate of interactivity, which imposes relatively long connection periods, required by these services, their use is not appropriate for mobile stations. This solution provides mobile user access to these services while keeping a low rate of the connections.

A Type-Based Implementation of a Language With Distributed Scope

Dominic Duggan and Piotr Przybylski

The ML programming language has several features that make it desirable as a language for distributed application programming. It supports first-class closures, which are useful for distributed scope and mobile agents. Type inference removes much of the tedium of lower-level programming, without compromising reliability. Finally ML provides a powerful type system, including type polymorphism. A dialect of ML intended for distributed application programming is introduced. A distinguishing characteristic of this implementation is the use of run-time type information, motivated by several constructs in the language. This is intended to motivate the use of run-time types in implementations of polymorphic languages intended for distributed programming.