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Klaim (a Kernel Language for Agents Interaction and Mobility) [1] is an experimental programming language specifically designed for programming mobile agents that supports a programming paradigm where both processes and data can be moved across different computing environments. The language relies on the use of explicit localities, and on allocation environments that associate logical localities to...
Experience gained from IBM’s Aglets project has led us to the conclusion that Java is far from being a language ideal for agent development. We discovered significant deficiencies in Java related to agent mobility, messaging, and security. Most importantly, we recognized that the Java programming language and Java-based agent frameworks do not provide a sufficient set of high-level abstraction mechanisms...
CO-OPN/2 is a formal language allowing the modelling of object-oriented software systems. A CO-OPN/2 model is composed of three kinds of entities, modelling three different parts of the global description, by three different formal semantics: COIL is the part of CO-OPN/2 allowing the model components and their coordination.
Adding the dimension of mobility to the engineering of complex software systems extends the scope of coordination. Since a mobile agent can roam a collection of different execution environments, physically distributed and possibly heterogeneous, interacting with both local resources and other mobile agents, both topology and security strictly relate to coordination. In this context, we propose an...
Colleague awareness tools are applications that allow a person to advertise their online presence and availability to others, as well as seeing the presence and availability of others on a network or internet. These tools typically provide two related services to users. We call these services presence notication and instant messaging.
Connectors are the glue for combining components and are a critical aspect of software architecture design. Providing a framework similar in spirit to that of the periodic table of chemical elements, this work strives to obtain a set of high level canonical properties that can describe all possible connectors and al- low operations to be defined over them. Connector factorization obtains a new connector...
Shared space coordination models such as Linda are ill-suited for structuring applications composed of erroneous or insecure components. This paper presents the Secure Object Space model. In this model, a data element can he locked with a key and is only visible to a process that presents a matching key to unlock the element. We give a precise semantics for Secure Object Space operations and discuss...
This paper addresses the opportunities for, and effects of, incorporating object attributes in Linda-like tuple-space systems. The focus is on exploring how the coordination attributes are affected by this enhancement, and investigating in what ways the classical Linda model needs to be modified. Particular emphasis is placed on the potential practical gains to be expected in both performance and...
New formal languages have been proposed for the specification of mobility aspects of systems and for understanding the recent devised technologies for mobile computing. In this paper we introduce MobiS, a specification language based on a tuple-spaces based model which species coordination bymultiset rewriting. We show how MobiS can be exibly used to specify architectures containing mobile...
Nowadays, the need for developing more and more complex applications with distributed capabilities has promoted the development of coordination models. The goal of these models is to express the synchronized interaction among the different components of a distributed application. Whilst the Concurrent Object Oriented Programming (COOP) paradigm has revealed special adaptation to the modeling of distributed...
Gamma is a language based on multiset rewriting aimed at separating coordination from computation. The “pipelining” technique turns a producer-consumer-type Gamma program with sequential composition into a parallel one, preventing the data from erroneously “flowing back” from the consumer to the producer. The resulting parallel composition offers more freedom to coordinate the computation and to choose...
The powerful abstraction mechanisms of functional programming languages provide the means to develop domain-specific programming languages within the language itself. Typically, this is realised by designing a set of combinators (higher-order reusable programs) for an application area, and by constructing individual applications by combining and coordinating individual combinators. This paper is concerned...
We propose to extend the synchronous language Esterel by coordination primitives and by an asynchronous parallel composition operation on the level of modules. This is to program reactive systems such that subsystems may proceed at their own speed without enforcing a global knowledge of time. We intend is to stick with the synchronous language paradigm as close as possible since we aim for properties...
We introduce Oikos_adtl, a specification language for distributed systems based on asynchronous communication via remot writings. The language is designed to support the composition of specifications. It allows expressing the global properties of a system in terms of the local properties of the components of coordination templates. Oikos-adtl is based on an asynchronous, distributed, temporal logic,...
A number of different coordination models for specifying inter-process communication and synchronisation rely on a notion of shared dataspace. Many of these models are extensions of the Linda coordination model, which includes operations for adding, deleting and testing the presence/absence of data in a shared dataspace. We compare the expressive power of three classes of coordination models...
We discuss three software architectures for coordination. All architectures are based on agents. Each agent has a local dataspace that contains shared distributed replicated data. The three architectures differ in the way agents communicate: either through an unordered broadcast, through an atomic broadcast, or through a synchronization among all agents. We first show how to represent both data-driven...
We describe a hierarchical model for coordination of concurrent activities based on grouping actors into casts and coordinating casts by actors that are designated directors. The hierarchical model provides a simple, intuitive basis for actor communication and coordination. Casts serve as abstraction units for naming, migration, synchronization and load balancing. Messengers are actors used to send...
Active networking aims at minimizing the functionality that is built into a data network: Programmable nodes inside the network enable the deployment of new services at run-time. In a bottom-up approach we presume a network void from any functionality and study the problem of deploying and providing a basic, externally defined and non-trivial distributed service. As a test case we use the robust election...
In this paper we describe the concept of mobile co-ordination, a general purpose approach to overcoming failure of agents when using distributed tuple spaces. We demonstrate why mobile co-ordination is better than using existing techniques such as transactions, how mobile co-ordination can provide extra functionality in the form of agent wills, and how the framework to provide this can be implemented...
A scheme has been developed that enables a Java program to be migrated across computers while preserving its execution state, such as the values of local variables and the dynamic extents of try-and-catch blocks. This scheme provides the programmer with exible control of migration, including transparent migration. It is based on source-code-level transformation. The translator takes as input code...
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