Component-based Systems Research Articles

Component-interaction automata as a verification-oriented component-based system specification

In the paper, we present a new approach to component interaction specification and verification process which combines the advantages of both architecture description languages (ADLs) at the beginning of the process, and a general formal verification-oriented model connected to verification tools at the end. After examining current general formal models with respect to their suitability for description of component-based systems, we propose a new verification-oriented model, Component-Interaction automata , and discuss its features. The model is designed to preserve all the interaction properties to provide a rich base for further verification, and allows the system behaviour to be configurable according to the architecture description (bindings among components) and other specifics (type of communication used in the synchronization of components).

A component-based specification approach for embedded systems using FDTs

This paper presents a framework for specification and testing of component-based embedded systems using formal description techniques (FDTs). We deal with embedded systems from the point of view of communication and thus we propose a communication model for them. We further explain the meaning of component-based embedded systems and how these can be specified using FDTs. FDTs such as Estelle and SDL are based on EFSMs (Extended finite State Machines) and have been widely used in the automation of the development process of protocols and communicating systems, i.e. for specification, analysis and validation purposes. The main goal of this work is to demonstrate the reusability of FDTs for component-based systems.

Assume-guarantee testing

Verification techniques for component-based systems should ideally be able to predict properties of the assembled system through analysis of individual components before assembly. This work introduces such a modular technique in the context of testing. Assume-guarantee testing relies on the (automated) decomposition of key system-level requirements into local component requirements at design time. Developers can verify the local requirements by checking components in isolation; failed checks may indicate violations of system requirements, while valid traces from different components compose via the assume-guarantee proof rule to potentially provide system coverage. These local requirements also form the foundation of a technique for efficient predictive testing of assembled systems: given a correct system run, this technique can predict violations by alternative system runs without constructing those runs. We discuss the application of our approach to testing a multi-threaded NASA application, where we treat threads as components.

Specification and design of component-based coordination systems by integrating coordination patterns

Rewriting logic has been revealed as a powerful tool to represent concurrent and state-transitions aspects in a declarative way, providing an adequate environment to specify and execute system representations. Moreover, rewriting logic is reflective, allowing for the definition of operations that transform, combine and manipulate specification modules by making use of the logic itself. Taking advantage of these capabilities, this paper presents a set of tools based on the rewriting logic language Maude to express the specifications of component-based systems with important coordination constraints, where coordination aspects are treated as separate components from functional ones. This representation allows for the testing of the system behavior from the early stages in the development process by executing the specifications. In addition, the development of basic coordination patterns using UML is presented to describe the coordination relationships between components in any system, providing a standard notation that complements the tools of the proposal.

Application of enterprise modelling technique for specifying a component-based system

The adoption of a set of enterprise modelling diagrams as a formal representation of the processes involved in developing a system based on a component-based approach is described in this paper. Illustration is given on how the information, resources, and events within the systems and the activities involved are abstracted, captured, and represented using a Computer Integrated Manufacturing Open System Architecture (CIMOSA)-based method. Such representation of the engineering processes is useful as it: (a) provides support for analysis of the system based on the component-based approach; (b) promotes understanding of the system implemented using the component-based approach; (c) enables better management of the complexities involved in describing the system; and (d) can potentially support system design.

Extracting Components from Object-Oriented System: A Transformational Approach

The increasing complexity and shorter life cycle of software have made it necessary to reuse software. Object-oriented development has not facilitated extensive reuse of software and it has become difficult to manage and understand modern object-oriented systems which have become very extensive and complex. However, components, compared with objects, provide more advanced means of structuring, describing and developing systems, because they are more coarse grained and have more domain-specific aspects than objects. In addition, they are also suited to a current distributed environment due to their reusability, maintainability and granularity. In this paper, we present a process of extracting components from object-oriented systems. We define some static metrics and guidelines that can be applied to transform object-oriented systems into component-based systems. Our process consists of two parts. First, basic components are created based on composition and inheritance relationships between classes. Second, the intermediate system is refined into a component-based system with our proposed static metrics and guidelines.

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.

SimQPN—A tool and methodology for analyzing queueing Petri net models by means of simulation

The queueing Petri net (QPN) paradigm provides a number of benefits over conventional modeling paradigms such as queueing networks and generalized stochastic Petri nets. Using queueing Petri nets (QPNs), one can integrate both hardware and software aspects of system behavior into the same model. This lends itself very well to modeling distributed component-based systems, such as modern e-business applications. However, currently available tools and techniques for QPN analysis suffer the state space explosion problem, imposing a limit on the size of the models that are tractable. In this paper, we present SimQPN—a simulation tool for QPNs that provides an alternative approach to analyze QPN models, circumventing the state space explosion problem. In doing this, we propose a methodology for analyzing QPN models by means of discrete event simulation. The methodology shows how to simulate QPN models and analyze the output data from simulation runs. We validate our approach by applying it to study several different QPN models, ranging from simple models to models of realistic systems. The performance of point and interval estimators implemented in SimQPN is subjected to a rigorous experimental analysis.

A systematic approach for structuring exception handling in robust component-based software

Component-based development (CBD) is recognized today as the standard paradigm for structuring large software systems. However, the most popular component models and component-based development processes provide little guidance on how to systematically incorporate exception handling into component-based systems. The problem of how to employ language-level exception handling mechanisms to introduce redundancy in componentbased systems is recognized by CBD practitioners as very difficult and often not adequately solved. As a consequence, the implementation of the redundant exceptional behaviour causes a negative impact, instead of a positive one, on system and maintainability. In this paper, we propose an approach for the construction of dependable component-based systems that integrates two complementary strategies: (i) a global exception handling strategy for inter-component composition and (ii) a local exception handling strategy for dealing with errors in reusable components. A case study illustrates the application of our approach to a real software system.

Member-Friendly Communication Is Goal of APA Computer Project

Back to table of contents Previous article Next article Association NewsFull AccessMember-Friendly Communication Is Goal of APA Computer ProjectMark MoranMark MoranSearch for more papers by this authorPublished Online:18 Mar 2005https://doi.org/10.1176/pn.40.6.00400002APA has embarked on a sweeping effort to integrate all of the disparate information systems used by various areas of the Association into one core system.That may sound like news in which only techno geeks would be interested, but the end result of the five-year, $3.5 million Project FUSION will be a more member-friendly APA.“Project FUSION is not just an information technology project,” said William Bruce, director of information technology at APA. “It's about positive change for the entire Association. It will provide an improved membership experience and new tools and applications for district branches, and will simplify staff operations by integrating multiple functions into one core processing system.”So, for instance, the database used by the Membership Department to manage member profiles and the database used by the Department of Association Governance to manage committee memberships will be integrated. These will then be linked to an APA Web site where members can access the information.System to Save Time, MoneyBruce said one tangible member benefit envisioned by Project FUSION is that members will be able to go online and manage their information profiles; in time, they may be able to pay their member dues online and subscribe to APA publications.Robert Hsiung, M.D., chair of APA's Ad Hoc Work Group on Information Systems, emphasized that Project FUSION will result in a better-functioning APA, inside and out. The work group provided overall guidance for the project.“The main goal is to have APA be more coordinated,” Hsiung told Psychiatric News.He likened the benefits of Project FUSION to those promised by the electronic medical record: coordination of services, improved efficiency, and lower cost. “Ultimately, it could help to make APA a more cost-efficient organization,” he said.Currently many APA offices have data stored in systems that are not linked.“For members, the first result of coordinating all this disparate data will be to make APA less confusing. If a member moves, for instance, he or she should have to change his or her address only once, and the whole system should know the new address,” he said.Likewise, from the Association's perspective, the integration will improve efficiency: when a member moves to a new district branch, that member's information will be readily accessible to the new DB through a specially designed Web interface.Disparate Systems, Disparate FunctionsBruce explained that APA's current information systems evolved“ helter skelter,” beginning in about 1990, when many of the Association's functions were still carried out manually. One by one, departments developed separate systems for specific functions. There was no long-term vision for making the systems work together and serve the Association's broader member needs.The result, he said, has been a hydra-head of 43 systems: 10 specialized applications used by management, three by Association Governance, six by American Psychiatric Publishing Inc. (APPI), seven by the Annual Meetings Office, five by the Division of Education and Career Development, and seven by other areas. The APA Web site adds five separate applications.“Technology is everywhere but is poorly organized, and the systems were implemented to mimic earlier manual processes,” Bruce said.Seeking from the initial planning stages to find a product that would be“ ready made” and require little customization, APA turned to the TIMSS Association Management System, marketed by TMA Resources of Vienna, Va.According to the TMA Resources Web site, TIMSS is a multitiered, component-based system designed to anticipate member-specific needs. Built-in flexibility allows customers to modify the system without the cost of custom scripting or programming.The TIMSS product has been used by professional societies such as the American Institute of Architects, American Urological Association, American Symphony Orchestra League, and North American Radiological Society.Bruce told Psychiatric News that the membership and governance systems will be the first to be integrated, with integration completed by the end of this summer. The second phase of integration, tentatively slated to be completed by the end of 2006, will involve systems used by the Division of Education and Career Development, Division of Advocacy, and the Office of HIV/AIDS Psychiatry. The final phase of integration will involve the systems used by APPI, American Psychiatric Foundation, and Annual Meetings Office.The new system is expected to be implemented and fully accessible by mid-2007.APA members can follow the progress of the project in the quarterlyFusion Focusnewsletter. The December issue, posted at<http://psych.org/members/newsletters/fusion/FUSIONFocus1—3.pdf>, is the most recent. More information is also available from William Bruce at (703) 907-7828. Information about TMA Resources and the TIMSS product is posted online at<www.tmaresources.com>.▪ ISSUES NewArchived

A component-based control system for agile manufacturing

Increasing complexity and interdependency in manufacturing enterprises requires an agile manufacturing paradigm. This paper considers the characteristics that a component-based control system needs to embody to support agility in this context. The concept of a component that incorporates automation hardware, software, control services, and manufacturing-related services into a basic modular unit is reported. A component encapsulates low-level, real-time implementation and component-specific knowledge, which are abstracted and exposed as standard interfaces to enable it to be integrated into a manufacturing system as a common, reusable building block. The concept and control of the component is outlined in this paper and the methodology for the implementation of a component-based control system is illustrated. Finally, the implementation of the component-based concept at Johann A. Krause Maschinenfabrik GmbH, a major manufacturer of automotive assembly automation systems, is described.

A Common Criteria Based Approach for COTS Component Selection.

Component-based software engineering (CBSE) endeavors to enable software developers to develop quality software systems with less time and resources than traditional development approaches. Software components must be identified and evaluated in order to determine if they provide required functionality for systems being developed. Consideration of security requirements for component selection is of interest. This research considers how the Common Criteria (CC), an internationally recognized standard for security requirements definition and security assessment of IT systems, can be applied towards the development of component-based systems. A CCbased COTS component selection process is proposed which integrates activities of the CC for security requirements specification and evaluation. Research questions are presented for the evaluation of the process to establish its value for COTS component selection as well as to identify areas for improvement.

Design, implementation, and performance of an automatic configuration service for distributed component systems

Component technology promotes code reuse by enabling the construction of complex applications by assembling off-the-shelf components. However, components depend on certain characteristics of the environment in which they execute. They depend on other software components and on hardware resources. In existing component architectures, the application developer is left with the task of resolving those dependencies, i.e. making sure that each component has access to all the resources it needs and that all the required components are loaded. Nevertheless, according to encapsulation principles, developers should not be aware of the component internals. Thus, it may be difficult to find out what a component really needs. In complex systems, such as the ones found in modern distributed environments, this manual approach to dependency management can lead to disastrous results. Current systems rely heavily on manual configuration by users and system administrators. This is tolerable now, when users have to manage a few computers. But, in the near future, people will have to deal with thousands of computing devices and it will no longer be acceptable to require the user to configure each of them. This paper presents the results of our 6 year research (from 1998 to 2003) in the area of automatic configuration, describing an integrated architecture for managing dependencies in distributed component-based systems. The architecture supports automatic configuration and dynamic resource management in distributed heterogeneous environments. We describe a concrete implementation of this architecture, present experimental results, and compare our approach to other works in the area. Copyright © 2005 John Wiley & Sons, Ltd.

Exception handling in the development of dependable component-based systems

Exception handling is a structuring technique that facilitates the design of software systems by encapsulating the process of error recovery. In this paper, we present a systematic approach for incorporating exceptional behaviour in the development of component-based software. The premise of our approach is that components alone do not provide the appropriate means to deal with exceptional behaviour in an effective manner, hence the need to consider the notion of collaborations for capturing the interactive behaviour between components when error recovery involves more than one component. The feasibility of the approach is demonstrated in terms of the mining control system case study. Copyright © 2004 John Wiley & Sons, Ltd.

Assessing the scalability of component-based frameworks

This paper proposes an approach to scalability analysis of component-based systems. A theoretical model of the orchestrated behavior of a system's components is developed and potential bottlenecks are identified. The model is derived by performing an analysis of the average number of messages that each involved entity has to deal with, i.e. receive, elaborate and possibly forward. By appropriately setting the various model parameters, it is possible to evaluate a system's behavior in a number of different scenarios. The model itself is based upon a queuing network paradigm, whereby each component is associated with a "service centre" characterized by specific values of both the message arrival rate and the service time: based on such values, the utilization coefficient of the service centers is computed and the potential bottlenecks are identified. The queuing network model is also exploited to evaluate the performance of the overall system under various configurations. The proposed approach is introduced and developed by taking the CADENUS system as a running example. CADENUS is a component-based framework designed and developed within a recent IST project, whose main goal resides in the provisioning of Premium IP services by means of an effective application of the so-called mediation paradigm.

A software approach to integrated machine vision

The importance of image capturing and illumination notwithstanding - the evaluation software as the &apos;byte-cast representation&apos; of the inspection strategy is the heart of every vision system. A particular problem of evaluation software is that its development takes place through continuous interaction with external constraints like the characteristics of the test pieces, imaging and illumination conditions. In the development of image processing software, as in other areas of software technology, two trends can be observed in the attempt to cope with these problems: i) rapid prototyping ii) component-based development. An integrated image processing system gives to the application engineer the performance of dedicated libraries, combined with the comfortable graphical environment of rapid prototyping tools and the extensibility of component-based systems.

A novel approach for component-based fault-tolerant software development

With the recent advancements in component-based software engineering, there is an increasing trend in developing applications for highly reliable and critical systems using pre-validated and reusable software components. As these applications are inherently complex and component-interactions are not straightforward, there is an immediate need for a methodology that could aid in composition of these reusable components ensuring the correctness of the composed software system. In this paper, we illustrate how the concepts of category theory can be utilized to develop component-based fault-tolerant software systems that encompass software components capable of tolerating particular types of faults. Our proposed framework for the development of a composite fault-tolerant program and verification of its overall correctness has been realized through a mechanized formal tool.

A systematic approach for structuring exception handling in robust component-based software

Abstract Component-based development (CBD) is recognized today as the standard paradigm for structuring large software systems. However, the most popular component models and component-based development processes provide little guidance on how to systematically incorporate exception handling into component-based systems. The problem of how to employ language-level exception handling mechanisms to introduce redundancy in componentbased systems is recognized by CBD practitioners as very difficult and often not adequately solved. As a consequence, the implementation of the redundant exceptional behaviour causes a negative impact, instead of a positive one, on system and maintainability. In this paper, we propose an approach for the construction of dependable component-based systems that integrates two complementary strategies: (i) a global exception handling strategy for inter-component composition and (ii) a local exception handling strategy for dealing with errors in reusable components. A case study illustrates the application of our approach to a real software system.

CONSTRAINT PROPAGATION AND PROGRESSIVE VERIFICATION FOR COMPONENT-BASED PROCESS MODEL

System assembly is one of the major issues in engineering complex component-based systems. This is especially true when heterogeneous, COTS and GOTS distributed systems, typical in industrial applications, are involved. The goal of system assembly is not only to make constituent components work together, but also to ensure that the components as a whole behave consistently and guarantee certain end-to-end properties. Despite recent advances, there is a lack of understanding about software composability, as well as theory and techniques for checking and verifying component-based systems. A theory of software system constraints about components, their environment and about system as a whole is the necessary foundation toward solid understanding of the composability of component-based systems. In this paper, we present a systematic approach for constraint specification and constraint propagation in concert with design refinement with a novel technique to ensure consistency between system-wide and component constraints in a design composition process of component-based systems. The consistent constraint propagation is used in our approach to drive progressive verification of the design. It allows us to verify overall design composition without interference of internal details of component designs. Verification is done separately at architectural and component levels without having to compose results of component analyses. A component can be safely replaced with alternative design without re-verifying the overall system composition so long as the replacement conforms to the corresponding interface and component constraint(s).

Component-Based Approach in the Development of a Knowledge-Based Planning Support System. Part 2: The Model and Knowledge Management Systems of KBPSS

In part 1 of our paper on the architecture of a component-based knowledge-based planning support system (KBPSS), we briefly introduced the ModelObjects model-management component and the KBSAgents knowledge-management component of the system. In this part we further examine the issues of model management and knowledge development in the ModelObjects and KBSAgents components. Model generalization and representation of ModelObjects are defined according to object-oriented methods and techniques. These procedures allow users to understand how planning models are processed in the system environment; and how the models in the system libraries can be reused to build more flexible domain models based on the users' problem definition and the interaction with the system interface. The model-retrieval and model-execution functions in ModelObjects can be further enhanced by KBSAgents from which model knowledge is constructed and managed; and models can be easily retrieved and selected on the basis of the user's request and the input to the system. To support model and model-knowledge development in KBSAgents, a frame-type object-oriented model-knowledge representation scheme is defined and constructed in the system. We discuss knowledge-based model selection by developing an Intelligent Model Selection System, an application subsystem in KBPSS which combines the functions of ModelObjects and KBSAgents and can be applied to assist users to select appropriate models from the model library for their problems. Throughout the paper, spatial interaction models are used as an example to illustrate the procedures and processes proposed in the system.