Today component- and service-based technologies play a central role in many aspects of enterprise computing. However, although the technologies used to define, implement, and assemble components have improved signific...
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ISBN:
(纸本)076952558X
Today component- and service-based technologies play a central role in many aspects of enterprise computing. However, although the technologies used to define, implement, and assemble components have improved significantly over recent years, techniques for verifying systems created from them have changed very little. The correctness and reliability of component-based systems are still usually checked using the traditional testing techniques that were in use before components and services became widespread, and the associated costs and overheads still remain high. This paper presents an approach that addresses this problem by making the system verification process more component-oriented. Based on the notion of built-in tests (BIT)-tests that are packaged and distributed with prefabricated, off-the-shelf components-the approach partially automates the testing process, thereby reducing the level of effort needed to establish the acceptability of the system. The approach consists of a method that defines how components should be written to support and make use of run-time tests, and a resource-aware infrastructure that arranges for tests to be executed when they have a minimal impact on the delivery of system services. After providing an introduction to the principles behind component-based verification and explaining the main features of the approach and its supporting infrastructure, we show by means of a case study how it can reduce system verification effort.
As quality of service (QoS)-enabled component middleware technologies gain widespread acceptance to build distributedreal-time and embedded (DRE) systems, it becomes necessary for these technologies to support real-t...
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As quality of service (QoS)-enabled component middleware technologies gain widespread acceptance to build distributedreal-time and embedded (DRE) systems, it becomes necessary for these technologies to support real-time publish/subscribe services, which is a key requirement of a large class of DRE systems. To date there have been very limited systematic studies evaluating different approaches to integrating real-time publish/subscribe services in QoS-enabled component middleware. This paper makes two contributions in addressing these key research questions. First, we evaluate the pros and cons of three different design alternatives for integrating publish/subscribe services within QoS-enabled component middleware. Second, we empirically evaluate the performance of our container-based design and compare it with mature object-orientedreal-time publish/subscribe implementations. Our studies reveal that both the performance and scalability of our design and implementation are comparable to its object-oriented counterpart, which provides a key guidance to the suitability of component technologies for DRE systems.
Although distributedreal-time (RT) systems are intrinsically complex to develop and maintain, the use of certain object-oriented (OO) technologies such as CORBA and CORBA-RT facilitates those tasks. This is the main ...
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Although distributedreal-time (RT) systems are intrinsically complex to develop and maintain, the use of certain object-oriented (OO) technologies such as CORBA and CORBA-RT facilitates those tasks. This is the main reason why these technologies are becoming increasingly popular. Moreover, CORBA is complemented with additional services that solve specific requirements for some applications, so developers may concentrate on the application functionality. Following this approach, this paper presents a new service that allows the synchronous scheduling of different activities in a distributed RT system in a simple and flexible way. This paper also explains how this service can be used for optimizing that access to shared resources in a distributed system and presents several experimental data that show the service performance
COTS simulation packages (CSPs) have proved popular in an industrial setting with a number of software vendors. In contrast, options for re-using existing models seem more limited. Re-use of simulation component model...
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Recently, new trends in application development for distributed platforms, such as the composable services model, attempt to provide more flexibility in system design, deployment and execution. Such trends, and partic...
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Recently, new trends in application development for distributed platforms, such as the composable services model, attempt to provide more flexibility in system design, deployment and execution. Such trends, and particularly the referred composable services model, can also be beneficial in real-timedistributed embedded systems, also providing a means to support more adaptive behaviors, reacting to the execution environment or coping with system reconfiguration. This paper explores a relatively new direction, which is the extension of the service-based model to dynamic, i.e. at run-time, composition in real-timedistributed environments, in order to support the level of flexibility and adaptibility referred above. The paper proposes an architecture to support such dynamic service composition that is based on the flexible time triggered communication paradigm (FTT).To achieve the desired goal, we also redefine the concepts of service and service-based application in the concept of the FTT paradigm. Finally, we show experimental results obtained with a prototype implementation of the proposed architecture that confirm its feasibility and good temporal behavior
In service-based systems, services from various providers can be integrated following specific workflows to achieve users' goals. These workflows are often executed and coordinated by software agents, which invoke...
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In service-based systems, services from various providers can be integrated following specific workflows to achieve users' goals. These workflows are often executed and coordinated by software agents, which invoke appropriate services based on situation changes. These agents need to be deployed on underlying platforms with respect to various requirements, such as access permission of agents, real-time requirements of workflows, and reliability of the overall system. Deploying these agents manually is often error-prone and time-consuming. Furthermore, agents need to migrate from hosts to hosts at runtime to satisfy deployment requirements. Hence, an automated agent deployment mechanism is needed. In this paper, an approach to automated agent deployment in service-base systems is presented. In this approach, the deployment requirements are represented as deployment policies, and techniques are developed for generating agent deployment plans by solving the constraints specified in deployment policies, and for generating executable code for runtime agent deployment and migration.
This paper provides three contributions to the study of quality of service (QoS) configuration in component-based DRE systems. First, we describe the challenges associated with mapping the platform-independent QoS pol...
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This paper provides three contributions to the study of quality of service (QoS) configuration in component-based DRE systems. First, we describe the challenges associated with mapping the platform-independent QoS policies of an application into platform-dependent values of QoS parameters used to configure the behavior of QoS-enabled component middleware. Second, we describe a novel approach that uses model-transformation to map these QoS policies onto component middleware QoS configuration parameters. Third, we demonstrate the use of model-checking to verify the properties of the transformation and automate the synthesis of configuration parameters required to tune the QoS-enabled component middleware. Our results indicate that model-transformation and model-checking provide significant benefits with respect to automation, reusability, verifiability, and scalability of the QoS mapping process compared with conventional middleware configuration techniques
In object-orientedreal-timecomputing scenarios, particularly where Corba is used in embedded systems with resource constraints, developers and system architects often utilize Corba object references as authorization...
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In object-orientedreal-timecomputing scenarios, particularly where Corba is used in embedded systems with resource constraints, developers and system architects often utilize Corba object references as authorization tokens. This paper investigates the security of this method in principle, and it presents the results of the analysis of the work and computing effort necessary for a potential attacker to fabricate Corba object references to existing objects for the purpose of illegitimately gaining access to these objects at the instance of seven widely used Corba products
service discovery is a critical task in distributedcomputing architectures for finding a particular service instance. Semantic annotations of services help to enrich the service discovery process. Semantic registries...
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ISBN:
(纸本)159593717X
service discovery is a critical task in distributedcomputing architectures for finding a particular service instance. Semantic annotations of services help to enrich the service discovery process. Semantic registries are an important component for the discovery of services and they allow for semantic interoperability through ontology-based query formulation and dynamic mapping of terminologies between system domains. This paper evaluates two semantic registries - OWLJessKB implementation and instanceStore - to determine the suitability of these with regards to the performance of loading ontologies, the query response time and the overall scalability for use in mathematical services. Copyright 2007 ACM.
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