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

Event-Condition-Action (ECA) languages are an intuitive and powerful paradigm for programming reactive systems. Usually, important features for an ECA language are reactive and reasoning capabilities, the possibility to express complex actions and events, and a declarative semantics. In this paper, we introduce ERA, an ECA language based on, and extending the framework of logic programs updates that, together with these features, also exhibits capabilities to integrate external updates and perform self updates to its knowledge (data and classical rules) and behaviour (reactive rules).

An event-condition-action logic programming language

Service aggregation is one of the main issues in the emerging area of service-oriented computing. The aim of this paper is to contribute to the long-term objective of lifting service aggregation from manual hand-crafting to a semi-automated engineered process. We present a methodology which, given a set of service contracts, tries to construct an aggregation of such services. Service contracts include a description of the service behaviour (expressed by a YAWL workflow), as well as an (ontology-annotated) signature. The core aggregation process basically performs a control-flow and an (ontology-aware) data-flow analysis of a set of YAWL workflows to build the contract of an aggregated service.

/pdf/towards-semi-automated-workflow-based-aggregation-of-web-3082l6fda5.pdf

Towards semi-automated workflow-based aggregation of web services

Docker containers run from Docker images, which can be distributed through so-called Docker registries. The currently available support for searching images in registries is however limited. Available registries (e.g., Docker Hub) only permit searching images "by name", i.e. by specifying a term occurring in the image name, in the image description or in the name of the user that created such image. In this paper we try to enhance the support for discovering Docker images by introducing DockerFinder, a microservice-based prototype that permits searching for images based on multiple attributes, e.g., image name, image size, or supported software distributions. DockerFinder crawls images from a remote Docker registry, it automatically analyses such images to produce multi-attribute descriptions to be stored in a local repository, and it permits searching for images by querying the local repository.

DockerFinder: Multi-attribute Search of Docker Images

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 based on shared dataspaces. The first class relies on Linda's communication primitives, while a second class relies on the more general notion of multi-set rewriting (e.g., like Bauhaus Linda or Gamma). Finally, we consider a third class of models featuring communication transactions that consist of sequences of Linda-like operations to be executed atomically (e.g., like in Shared Prolog or PoliS).

Antonio Brogi

Papers

An event-condition-action logic programming language

Towards semi-automated workflow-based aggregation of web services

DockerFinder: Multi-attribute Search of Docker Images

On the Expressiveness of Coordination Models

TosKer: A synergy between TOSCA and Docker for orchestrating multicomponent applications