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

Managing complex applications over heterogeneous clouds is one of the emerging problems in the cloud era. The OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) aims at solving this problem by providing a language to describe and manage complex cloud applications in a portable and vendor-agnostic way. TOSCA permits to define an application as an orchestration of components, whose types can specify states, requirements, capabilities and management operations — but not how they interact with each other.

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Modelling and Analysing Cloud Application Management

Although very simple and elegant, Linda-style coordination models lack the notion of time, and are therefore not able to precisely model real-life coordination applications, featuring time-outs and soft real-time constraints. This paper aims at introducing time in these models. To that end, we consider two notions of time, relative time and absolute time, and, for each notion, two types of features. On the one hand, with respect to relative time, we describe two extensions: (i) a delay mechanism to postpone the execution of communication primitives, and (ii) explicit deadlines on the validity of tuples and on the duration of suspension of communication operations. On the other hand, for absolute time, we introduce: (iii) a wait primitive capable of waiting till an absolute point of time, and (iv) time intervals, both on tuples in the data store and on communication operations.

The resulting four coordination models are analyzed and compared both from the semantics viewpoint and from the implementation viewpoint. Moreover, a few programming examples suggest their practical interest.

On Timed Coordination Languages

ToscaMart: A method for adapting and reusing cloud applications

Predictive Analysis to Support Fog Application Deployment

The ability to describe and verify the concurrent behaviour of interacting components is a key aspect in the development of large component-based software systems. We propose a simple interface description language which allows software designers to easily specify the interaction pattern of a component that will have to interact with other components. A set of interaction patterns forms a context which may evolve either because of interactions occurring within the context, or because a new component joins the context. The main interest of the overall setting is that it supports the efficient verification — both statically and dynamically — of interesting properties of open interacting systems.

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Antonio Brogi

Papers

Modelling and Analysing Cloud Application Management

On Timed Coordination Languages

ToscaMart: A method for adapting and reusing cloud applications

Predictive Analysis to Support Fog Application Deployment

Coordinating interaction patterns