The ARC Programming Model – Language Constructs for Coordination

Seminar on Coordination Models, …, 1996

Coordination technology addresses the construction of open, flexible systems from software agents in distributed systems. Most of the work on coordination technology so far has focused on the development of special coordination languages and environments that provide the basic mechanisms for realizing the coordination layer of a distributed application. Typically each new language proposes its own set of coordination abstractions that realizes a particular paradigm for realizing coordination. Coordination problems, however, are not always well-suited to a particular paradigm. Instead of proposing a new language, we are attempting to develop an open set of software components that realize various useful coordination abstractions. We are validating our approach by developing an experimental framework of coordination components in Java and applying them to a canonical set of sample applications. We present our initial analysis of the coordination domain, and give a few examples of simple applications using the developed coordination components.

2001

data resources: over time, a host whose CPU was pegged may become idle and one data source may be exhausted Writing distributed programs is difficult. To ease this while another comes online. Since the networ ~ infras task, we introduce a new programming abstraction. which we call a mobility attribute. Mobility attributes provide a syntax that describes the mobility semantics ofprogram tructure on which these systems run is also dynamic, with systems joining and crashing, these systems must also be extensible. They m·ust support host and resource discovery, components. Programmers attach mobility attributes to incorporate new hardware and robustly cope with changing program components to dynamically control the placement ofthese components within the network. Mobility attributes intercept component invocations and decide whether and where to move a component before the component executes. network conditions. To fully exploit this runtime environment, distributed programming models m...

Informatica (slovenia), 2008

This paper presents a framework to support Open Distributed and Embedded (ODE) application development based on the Actor-Role-Coordinator (ARC) model. The ARC model is a role-based coordination model developed to address three main concerns inherent in an ODE system: dynamicity, scalability, and stringent QoS requirements. It treats an ODE system as a composition of concurrent computation and coerced coordination. In particular, the ARC model uses concurrent objects that communicate with each other through asynchronous messages, i.e., actors, to model the concurrent computation of an ODE system, while the system's QoS requirements are mapped to coordination constraints. Coordination entities, i.e., roles and coordinators, impose coordination constraints on concurrent actors transparently through message interceptions and manipulations. In the ARC model, roles provide actor behavior abstractions for coordinators and coordinators are responsible for coordinating roles. In addition, a role also has local coordination responsibilities among actors belonging to that role. This coordination is called intra-role coordination which complements the inter-role coordination performed by the coordinators. In other words, under the ARC model, an ODE application is modeled by three orthogonal layers: computation, intrarole coordination and inter-role coordination. This separation not only improves software modularity and reusability, but also allows different levels of compositions. Our experiments show that the model scales well as the number of entities involved in the system increases, and that the performance overhead introduced by the external coordination layers is limited.

Lecture Notes in Computer Science, 2010

Lecture Notes in Computer Science, 2000

A rather recent approach in programming parallel and distributed systems is that of coordination models and languages. Coordination programming enjoys a number of advantages such as the ability to express different software architectures and abstract interaction protocols, supporting multilinguality, reusability and programming-in-the-large, etc. In this paper we show the potential of control-or event-driven coordination languages to be used as languages for expressing dynamically reconfigurable software architectures. We argue that control-driven coordination has similar goals and aims with reconfigurable environments and we illustrate how the former can achieve the functionality required by the latter.

The Ninth IEEE Workshop on Future Trends of Distributed Computing Systems, 2003. FTDCS 2003. Proceedings.

The implementation of distributed applications is an increasingly complex task. Not only the users require new and more complex functionalities but these have to be provided considering a large set of non-functional requirements such as high performance, fault-tolerance, timeliness, etc. Therefore, communication and coordination services, offered at the operating system or middleware level, assume a fundamental role in the development of efficient and robust software. This paper discusses the problem of designing and implementing the communication and coordination support for distributed applications. One way to implement these services is to rely on application-specific solutions, in an attempt to obtain the best performance possible. In this paper, we champion a different approach that consists in supporting adaptation, configuration and composition at all levels of the system development, namely: i) abstractions; ii) algorithms and; iii) implementations. Using different examples we show that this approach allows to obtain solutions that are generic, re-usable and efficient.

2005

must be non-intrusive and based on formal executable specification languages such as Behavioural IDL. Such languages and techniques should support automatic and dynamic adaptation, that is, the adaptation of a component just in the moment in which the component joins the context supported by automatic and transparent procedures. For that purpose Software Adaptation promotes the use of software adaptors-specific computational entities for solving these problems. The main goal of software adaptors is to guarantee that software components will interact in the right way not only at the signature level but also at the protocol, Quality of Service and semantic levels. These are the proceedings of the 2nd International Workshop on Coordination and Adaptation Issues for Software Entities (WCAT'05), affiliated with the 19th European Conference on Object-Oriented Programming (ECOOP'2005), held in Glasgow (United Kingdom) on July 25, 2005. These proceedings contain the 12 position papers selected for participating in the workshop. The topics of interest of WCAT'05 covered a broad number of fields where coordination and adaptation have an impact: models, requirements identification, interface specification, software architecture, extra-functional properties, documentation, automatic generation, frameworks, middleware and tools, and experience reports. The WCAT workshops series tries to provide a venue where researchers and practitioners on these topics can meet, exchange ideas and problems, identify some of the key issues related to coordination and adaptation, and explore together and disseminate possible solutions. Workshop Format To establish a first contact, all participants will make a short presentation of their positions (five minutes maximum, in order to save time for discussions during the day). Presentations will be followed by a round of questions and discussion on participants' positions. From these presentations, a list of open issues in the field must be identified and grouped. This will make clear which are participants' interests and will also serve to establish the goals of the workshop. Then, participants will be divided into smaller groups (about 4-5 persons each), attending to their interests, each one related to a topic on software coordination and adaptation. The task of each group will be to discuss about the assigned topic, to detect problems and its real causes and to point out solutions. Finally a plenary session will be held, in which each group will present their conclusions to the rest of the participants, followed by some discussion.

Fundamenta Informaticae, 2006

… of the 1998 ACM symposium on …, 1998