Component-based System Architecture Research Articles

Component-Based Systems Reconfigurations Using Graph Transformations with GROOVE

Component-based systems permit standardisation and re-usability of code through the use of components. The architecture of component-based systems can be modified thanks to dynamic reconfigurations, which contribute to systems’ (self-)adaptation by adding or removing components without incurring any system downtime. In this context, the present article describes a formal model for dynamic reconfigurations of component-based systems. It provides a way of expressing runtime reconfigurations of a system and proving their correctness according to a static invariant for consistency constraints and/or a user-provided post-condition. Guarded reconfigurations allow us to build reconfigurations based on primitive reconfiguration operations using sequences of reconfigurations and the alternative and the repetitive constructs, while preserving configuration consistency. A practical contribution consists of the implementation of a component-based model using the GROOVE graph transformation tool. This implementation is illustrated on a cloud-based multi-tier application hosting environment managed as a component-based system. In addition, after enriching the model with interpreted configurations and reconfigurations in a consistency compatible manner, component systems’ implementations are related to their specifications by a simulation relation.

Fundamentals of safety management: The Offshore Helicopter Transportation System Model

A precondition for a holistic, systemic and systematic management of offshore helicopter operations’ safety is an in-depth understanding of the corresponding system. This is essential because the components and the interactions between these components largely shape system and human performance, with the potential to create safety hazards and risks. However, current techniques of system component description in aviation are poorly specified, which contributes to a silo approach to hazard identification and risk analysis, poor safety management and missed safety targets. This paper addresses this shortcoming by developing a novel process to characterise the component-based system architecture of commercial air operations and implementing the process to create the Offshore Helicopter Transportation System Model. The paper discusses the theoretical justifications for generating such a system model and the shortcomings of the techniques currently recommended. In order to redress these, the process combines two task analysis techniques to derive an unbiased seminal system model, which is then compared to relevant models in the safety literature to ensure completeness. The process and resulting system model are validated by carefully selected subject matter experts during training sessions in high-fidelity flight simulators. The process can be applied to describe, by means of a system model, the activities of other industries in the aviation domain. Moreover, the model derived provides, for the first time, the necessary anchoring for future safety analyses in offshore helicopter operations.

Component-based Systems Reconfigurations Using Graph Grammars

Dynamic reconfigurations can modify the architecture of component-based systems without incurring any system downtime. In this context, the main contribution of the present article is the establishment of correctness results proving component-based systems reconfigurations using graph grammars. New guarded reconfigurations allow us to build reconfigurations based on primitive reconfiguration operations using sequences of reconfigurations and the alternative and the repetitive constructs, while preserving configuration consistency. A practical contribution consists of the implementation of a component-based model using the GROOVE graph transformation tool. Then, after enriching the model with interpreted configurations and reconfigurations in a consistency compatible manner, a simulation relation is exploited to validate component systems’ implementations. This sound implementation is illustrated on a cloud-based multitier application hosting environment managed as a component-based system.

A flexible and scalable component-based system architecture for video surveillance as a service, running on infrastructure as a service

There are many proposals for moving traditional video surveillance systems into the cloud, commonly known as Video Surveillance as a Service (VSaaS). Most systems use Hadoop technology for storing ...

Assembling Components using SysML with Non-Functional Requirements

Non-functional requirements of component based systems are important as their functional requirements, therefore they must be considered in components assembly. These properties are beforehand specified with SysML requirement diagrams. We specify component based system architecture with SysML block definition diagram, and component behaviors with sequence diagrams. We propose to specify formally component interfaces with interface automata, obtained from requirement and sequence diagrams. In this formalism, transitions are annotated with costs to specify non-functional property. The compatibility between components is performed by synchronizing their interface automata. The approach is explained with the example of the electric car CyCab, where the costs are associated to energy consumption of component actions. Our approach verifies whether, a set of components, when composed according to the system architecture, achieve their tasks by respecting their non-functional requirements.

RELIABILITY MODEL FOR COMPONENT-BASED SYSTEMS IN COSMIC (A CASE STUDY)

Software component technology has a substantial impact on modern IT evolution. The benefits of this technology, such as reusability, complexity management, time and effort reduction, and increased productivity, have been key drivers of its adoption by industry. One of the main issues in building component-based systems is the reliability of the composed functionality of the assembled components. This paper proposes a reliability assessment model based on the architectural configuration of a component-based system and the reliability of the individual components, which is usage- or testing-independent. The goal of this research is to improve the reliability assessment process for large software component-based systems over time, and to compare alternative component-based system design solutions prior to implementation. The novelty of the proposed reliability assessment model lies in the evaluation of the component reliability from its behavior specifications, and of the system reliability from its topology; the reliability assessment is performed in the context of the implementation-independent ISO/IEC 19761:2003 International Standard on the COSMIC method chosen to provide the component's behavior specifications. In essence, each component of the system is modeled by a discrete time Markov chain behavior based on its behavior specifications with extended-state machines. Then, a probabilistic analysis by means of Markov chains is performed to analyze any uncertainty in the component's behavior. Our hypothesis states that the less uncertainty there is in the component's behavior, the greater the reliability of the component. The system reliability assessment is derived from a typical component-based system architecture with composite reliability structures, which may include the composition of the serial reliability structures, the parallel reliability structures and the p-out-of-n reliability structures. The approach of assessing component-based system reliability in the COSMIC context is illustrated with the railroad crossing case study.

Runtime recovery and manipulation of software architecture of component-based systems

Recently, more attention is paid to the researches and practices on how to use software architecture in software maintenance and evolution to reduce their complexity and cost. The key in such architecture-based maintenance and evolution is to recover software architecture from existing systems. Almost all studies on architecture recovery focus on analyzing the source code and other documents. Such recovered software architecture can hardly capture runtime states and behaviors of the system. At the same time, current work pays little attention on how to change the system directly via manipulating the recovered software architecture. This paper presents a novel approach to recovering software architecture from component based systems at runtime and changing the runtime systems via manipulating the recovered software architecture. Containing much more details than the designed software architecture, the recovered software architecture can accurately and thoroughly describe the actual states and behaviors of the runtime system. It can be described formally with the extension of traditional architecture description language, which enables the recovered software architecture to absorb the semantics embedded in the designed software architecture. The recovered software architecture can be represented as multiple views so as to help different users to control the complexity from different concerns. Based on the reflective ability of the component framework, the recovered software architecture is up-to-date at any time and changes made on it will immediately lead to the corresponding changes in the runtime system. The approach presented in this paper is demonstrated on PKUAS, a reflective J2EE (Java 2 Platform Enterprise Edition) application server, and the performance is also evaluated.

Ugatze Interopérabilité entre composants dirigée par les modèles

Exposed work relates to the engineering of heterogeneous distributed systems based on the re-use of components. Those are high level software components considered as autonomous in term of run-time. Our research field deals with several research domains: distributed systems, reuse, interoperability, components, model driven engineering. In this article, our proposal is a component metamodel, called Ugatze, allowing to reuse legacy components We present the conceptual level allowing to build component based system architectures, and the annotation level and its extra functional properties. A reuse process exploits those levels, building a conceptual model and exploiting annotation properties in order to perform an automatic integration. This process is supported by a model driven CASE tool. This article describes the metamodel, the process and the tool defined by the way of meta modelling standards.

APPLYING THE 3C MODEL TO GROUPWARE DEVELOPMENT

This paper introduces an approach based on the 3C (communication, coordination and cooperation) collaboration model to the development of collaborative systems. The 3C model is studied by means of a detailed analysis of each of its three elements, followed by a case study of a learningware application and the methodology of a web-based course, both designed based on this model. Moreover, this paper describes a component-based system architecture following this 3C approach.