The real-time Specification for Java (RTSJ) [10] is becoming a popular choice in the world of real-time programming. However, the complexities introduced by RTSJ bring the needs for an extensive framework comprising a...
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ISBN:
(纸本)9780769531328
The real-time Specification for Java (RTSJ) [10] is becoming a popular choice in the world of real-time programming. However, the complexities introduced by RTSJ bring the needs for an extensive framework comprising all the aspects of RTSJ development. As the first contribution of this paper, we present a real-timecomponent model directly fitting the needs of RTSJ. Our motivation is to clearly separate real-time and business concerns of applications. We further argue that the RTSJ concerns need to be considered at early stages of architecture design in order to mitigate the complexities of the implementation phase. Therefore, as our second contribution, we propose a design process introducing gradually RTSJ concepts into the architecture. We are thus able to alleviate the development of real-time systems and to tailor them for different real-time conditions. Finally, we demonstrate the feasibility of our solution on an example scenario.
serviceoriented architecture (SOA) is becoming established in computing as a means to integrate processing and data across organisations. This paper proposes that system-level integration can benefit from service ori...
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ISBN:
(纸本)9780769531328
serviceoriented architecture (SOA) is becoming established in computing as a means to integrate processing and data across organisations. This paper proposes that system-level integration can benefit from serviceoriented architectural descriptions and loose coupling between the problem domain requirements and different system solutions. The problem domain is exemplified as military capability, from the UK Ministry of Defence (MoD), in particular, Network Enabled Capability (NEC). Representations of military capability in the problem domain can be described in terms of processes. The processes are sequences of functions that can be described as services. Then different types of system solutions can implement the described services. Firstly, the paper presents an overview of conceptual SOA and in the context of military capability compares three levels of service integration: business services, systems services and computingservices. Secondly, the paper presents a framework for evaluating the performance and effectiveness of service integration to compare different solutions in delivering military capability.
Effective resource management for distributedreal-time embedded (DRE) systems is hard due to their unique characteristics, including (1) constraints in multiple resources and (2) highly fluctuating resource availabil...
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ISBN:
(纸本)9780769531328
Effective resource management for distributedreal-time embedded (DRE) systems is hard due to their unique characteristics, including (1) constraints in multiple resources and (2) highly fluctuating resource availability and input workload. DRE systems can benefit from a middleware framework that enables adaptive resource management algorithms to ensure application QoS requirements are met. This paper identifies key challenges in designing and extending resource allocation algorithms for DRE systems. We present an empirical study of bin-packing algorithms enhanced to meet these challenges. Our analysis identifies input application patterns that help generate appropriate heuristics for using these algorithms effectively in DRE systems.
This paper introduces ReDAC, a new algorithm for dynamic reconfiguration of multi-threaded applications. In order to achieve high reliability and availability, distributedcomponent software has to support dynamic rec...
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ISBN:
(纸本)9780769531328
This paper introduces ReDAC, a new algorithm for dynamic reconfiguration of multi-threaded applications. In order to achieve high reliability and availability, distributedcomponent software has to support dynamic reconfiguration. Typical examples include the application of hot-fixes to deal with security vulnerabilities. ReDAC can be implemented on top of the modern component-platforms Java and NET. We extend the statical term component, denoting a unit of deployment, to runtime by defining a capsule (runtimecomponent instance) to be a set of interconnected objects. This allows us to apply dynamic updates at the level of components during runtime without stopping whole applications. Using system-wide unique identifiers for threads (logical thread IDs), we can detect and also bring capsules into a reconfigurable state by selectively blocking threads, relying on data structures maintained by additional logic integrated into the capsules using aspect-oriented programming. An important contribution of this paper is that ReDAC supports the dynamic reconfiguration of distributed multi-threaded and re-entrant components with cyclic call dependencies.
Recently, the application domains where the development of systems with temporal guarantees is needed have increased. The majority of such domains are dynamic environments where the classical design approach is no lon...
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ISBN:
(纸本)9780769531328
Recently, the application domains where the development of systems with temporal guarantees is needed have increased. The majority of such domains are dynamic environments where the classical design approach is no longer applicable since it is too pessimistic. Thus, new challenges arise to adapt the current methodologies used in different architectural levels to these new environments. New directions and paradigms are needed to allow combining functional flexibility and dynamism with temporal predictability. The current work addresses these new challenges through the exploration of the applicability of concepts from the serviceoriented paradigm to distributedreal-time systems. We propose a concrete system model based on a holistic time-triggered-based approach for design and configuration. Based on this model, we analyse the architectural entities required for two different architectural design approaches: static, when no reconfigurations at run-time are admitted, and dynamic, when these reconfigurations are possible. An exhaustive composition algorithm is also proposed.
In this paper we describe our approach for developing a QoS-aware, dependable execution environment for large-scale distributed stream processing applications. distributed stream processing applications have strong ti...
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ISBN:
(纸本)9780769531328
In this paper we describe our approach for developing a QoS-aware, dependable execution environment for large-scale distributed stream processing applications. distributed stream processing applications have strong timeliness and security demands. In particular, we address the following challenges: (1) propose a real-time dependable execution model by extending the component-based execution model with real-time and dependability properties, and (2) develop QoS-aware application composition and adaptation techniques that employ resource management strategies and security policies when discovering and selecting application components. Our approach enables us to develop a distributed stream processing environment that is predictable, secure, flexible and adaptable.
Predictable deployment and configuration (D&C) of components in response to dynamic environmental changes or system mode changes is essential for ensuring open distributedreal-time and embedded (DRE) system real-...
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ISBN:
(纸本)9780769531328
Predictable deployment and configuration (D&C) of components in response to dynamic environmental changes or system mode changes is essential for ensuring open distributedreal-time and embedded (DRE) system real-time QoS. This paper provides three contributions to research on the predictability of D&C for component-based open DRE systems. First, we describe how the dependency relationships among different components and their criticality levels can cause deployment order inversion of tasks, which impedes deployment predictability. Second, we describe how to minimize D&C latency of mission-critical tasks with a multi-graph dependency tracing and graph recomposition algorithm called CaDAnCE. Third, we empirically evaluate the effectiveness of CaDAnCE on a representative open DRE system case study based on NASA Earth Science Enterprise's Magnetospheric Multi-Scale (MMS) mission system. Our results show that CaDAnCE avoids deployment order inversion while incurring negligible (<1%) performance overhead, thereby significantly improving D&C predictability.
The service-oriented architectural style is widely perceived today. However service orientation is a very general concept and its application in real-life situations is somewhat ambiguous. This is partially due to the...
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ISBN:
(纸本)9780769533735
The service-oriented architectural style is widely perceived today. However service orientation is a very general concept and its application in real-life situations is somewhat ambiguous. This is partially due to the fact that service-oriented principles are subject to interpretation rather than elements of the style. In this paper we propose a set of design metrics for service-oriented design. Based on an established metric for the coupling of component-based systems we introduce a complexity metric by the means of service coupling. We argue that service aggregators and the centralization of a system's control flow is appropriate to address a system's complexity. In order to approach an objective design that incorporates these principles, we introduce four metrics for the analysis of how a system handles its complexity with service-oriented means. Finally, we apply the presented metrics to an enterprise-scale real-life case study that we have conducted
As ITS technology evolves, very large volume of traffic data can be obtained in real-time. Traffic data are continuously produced and they can be considered as a kind of stream data. Currently, such traffic data are n...
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ISBN:
(纸本)9780769531328
As ITS technology evolves, very large volume of traffic data can be obtained in real-time. Traffic data are continuously produced and they can be considered as a kind of stream data. Currently, such traffic data are not maintained permanently because of the storage limitations of operational systems. Therefore, it was impossible to compare temporal historical patterns over long time periods. In this paper, we propose a traffic data management scheme, which can handle historical data as well as current data. The proposed scheme is based on the GALIS architecture, which is a cluster-based distributedcomputing system architecture that consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone. Some experimental results showing performance factors are also explained.
component Based Software Development (CBSD) has been established in the development of automotive real-time embedded applications at Bosch. CBSD together with Software Product Line (SPL) practice has improved software...
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ISBN:
(纸本)9780769531328
component Based Software Development (CBSD) has been established in the development of automotive real-time embedded applications at Bosch. CBSD together with Software Product Line (SPL) practice has improved software reuse, productivity, quality and complexity management, by raising the level of abstraction for software constructions and by sharing services. Although CBSD has contributed to the aforementioned improvement in the software development practice, the existing Bosch component model often requires software developers to take a close look at the implementation including models (e.g., ASCET-MD1) and even complex source code to understand software behavior and dependencies when reusing and adapting software components. This hinders the realization of the full benefits of CBSD, as the available information on the component level does not sufficiently describe important aspects of software behavior. This paper presents the concepts and case studies of 'signal flows' and 'mode dependent signal flows', which provide crucial software behavior information for realtime embedded systems at the component level.
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