物件導向軟體之架構(Object-Oriented Software Construction)探討

[서평]「Component Software」 - Beyond Object-Oriented Programming -

A new class of models, formalisms and mechanisms has recently evolved for describing concurrent and distributed computations based on the concept of ``coordination''''. The purpose of a coordination model and associated language is to provide a means of integrating a number of possibly heterogeneous components together, by interfacing with each component in such a way that the collective set forms a single application that can execute on and take advantage of parallel and distributed systems. In this chapter we initially define and present in sufficient detail the fundamental concepts of what constitutes a coordination model or language. We then go on to classify these models and languages as either ``data-driven'''' or ``control-driven'''' (also called ``process-'''' or ``task-oriented''''). Next, the main existing coordination models and languages are described in sufficient detail to let the reader appreciate their features and put them into perspective with respect to each other. The chapter ends with a discussion comparing the various models and some conclusions.

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Coordination models and languages

A super-peer is a node in a peer-to-peer network that operates both as a server to a set of clients, and as an equal in a network of super-peers. Super-peer networks strike a balance between the efficiency of centralized search, and the autonomy, load balancing and robustness to attacks provided by distributed search. Furthermore, they take advantage of the heterogeneity of capabilities (e.g., bandwidth, processing power) across peers, which recent studies have shown to be enormous. Hence, new and old P2P systems like KaZaA and Gnutella are adopting super-peers in their design. Despite their growing popularity, the behavior of super-peer networks is not well understood. For example, what are the potential drawbacks of super-peer networks? How can super-peers be made more reliable? How many clients should a super-peer take on to maximize efficiency? we examine super-peer networks in detail, gaming an understanding of their fundamental characteristics and performance tradeoffs. We also present practical guidelines and a general procedure for the design of an efficient super-peer network.

Designing an Super-Peer Network

All one needs to know about fog computing and related edge computing paradigms: A complete survey

This paper aims at offering an insightful synthesis of different compositional semantics for logic program composition which have been developed in the literature. In particular, we will analyse the notions of program equivalence, compositionality, and full abstraction for logic programs. We will show how the notion of supported interpretation provides a unifying compositional model-theoretic characterisation both of positive programs and of programs containing negation.

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On the Semantics of Logic Program Composition

The implementation of a distributed model for logic programming based on multiple-headed clauses

Continuous reasoning has proven effective in incrementally analysing changes in application codebases within Continuous Integration/Continuous Deployment (CI/CD) software release pipelines. In this article, we present a novel declarative continuous reasoning approach to support the management of multi-service applications over the Cloud-IoT continuum, in particular when infrastructure variations impede meeting application's hardware, software, IoT or network QoS requirements. We show how such an approach brings considerable speed-ups compared to non-incremental reasoning.

Continuous Reasoning for Managing Next-Gen Distributed Applications.

Recent technology advances are pushing towards a full integration of low-capacity networked devices in pervasive embedded P2P systems. One of the challenges of such integration is to allow low-capacity devices both to invoke and to provide services, while featuring enhanced service discovery mechanisms that are necessary to automate service invocation in pervasive environments. In this paper we present a two-tiered approach to enabling enhanced service discovery in embedded P2P systems. We first present a super-peer based overlay network featuring a matching capability aware routing of messages, and saving the resource consumption of low-capacity devices while keeping the overall network traffic low. We then present a service discovery protocol that exploits such underlying overlay network to suitably distribute service contracts on devices capable of analysing them, thus enabling enhanced service discovery even in nets mainly formed by low-capacity devices. Finally, we discuss some experimental results that confirm the viability of the proposed approach.

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A Two-Tiered Approach to Enabling Enhanced Service Discovery in Embedded Peer-to-Peer Systems

The paper proposes a theoretical study of a coordination language embodying Linda's asynchronous communication primitives with a refined matching mechanism based on pairs composed of attribute names associated with their values. Computations in this language are described by means of an operational semantics, reporting the whole traces of executions. The non-compositionality of this intuitive operational semantics motivates the design of a compositional and fully abstract denotational semantics.

Antonio Brogi

Papers

On the Semantics of Logic Program Composition

The implementation of a distributed model for logic programming based on multiple-headed clauses

Continuous Reasoning for Managing Next-Gen Distributed Applications.

A Two-Tiered Approach to Enabling Enhanced Service Discovery in Embedded Peer-to-Peer Systems

Fully Abstract Semantics for a Coordination Model with Asynchronous Communication and Enhanced Matching