Service-orientedcomputing (SOC) provides a flexible framework in which applications may be built up from services, often distributed across a network. One of the promises of SOC is that of Dynamic Binding where abstr...
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ISBN:
(纸本)9781479921133
Service-orientedcomputing (SOC) provides a flexible framework in which applications may be built up from services, often distributed across a network. One of the promises of SOC is that of Dynamic Binding where abstract consumer requests are bound to concrete service instances at runtime, thereby offering a high level of flexibility and adaptability. Existing research has so far focused mostly on the design and implementation of dynamic binding operations and there is little research into a comprehensive evaluation of dynamic binding systems, especially in terms of system failure and dependability. In this paper, we present a novel, extensible evaluation framework that allows for the testing and assessment of a Dynamic Binding System (DBS). Based on a fault model specially built for DBS's, we are able to insert selectively the types of fault that would affect a DBS and observe its behavior. By treating the DBS as a black box and distributing the components of the evaluation framework we are not restricted to the implementing technologies of the DBS, nor do we need to be co-located in the same environment as the DBS under test. We present the results of a series of experiments, with a focus on the interactions between a real-life DBS and the services it employs. the results on the NECTISE Software Demonstrator (NSD) system show that our proposed method and testing framework is able to trigger abnormal behavior of the NSD due to interaction faults and generate important information for improving both dependability and performance of the system under test.
In the recent years we have witnessed a proliferation of distributed stream processing systems that need to operate efficiently, even when data bursts occur. Examples include road traffic networks, processing of finan...
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ISBN:
(纸本)9781479921133
In the recent years we have witnessed a proliferation of distributed stream processing systems that need to operate efficiently, even when data bursts occur. Examples include road traffic networks, processing of financial feeds, network monitoring and real-time sensor data analysis systems. An important challenge in managing these systems is effective resource management and meeting the QoS demands of the stream processing applications under different workload conditions, even under bursts. In this paper we present our approach that aims to predict the execution times of the distributed stream processing applications by taking into account the effects of the bursts and what is the typical workload of the stream processing system. Our approach builds application data rate patterns at run-time and predicts the effect of the burst on the performance of the applications, to identify whether there is a need to react on the onset of a burst. Our detailed experimental results over our Synergy middleware illustrate that our approach is practical, depicts good performance and has low resource overhead.
this work is motivated by the needs to synchronize task executions where tasks might use semaphores to protect their critical sections and run over accelerators. In particular, the Priority Ceiling Protocol is extende...
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ISBN:
(纸本)9781479944309
this work is motivated by the needs to synchronize task executions where tasks might use semaphores to protect their critical sections and run over accelerators. In particular, the Priority Ceiling Protocol is extended to manage priority inversion caused by accelerator usages. By recognizing the difference between an accelerator and a semaphore, higher-priority tasks are less likely blocked by lower-priority tasks, due to their requests for an accelerator. In particular, blocking that will not contribute to any deadlock and/or chained blocking is allowed in a managed way, with an objective to maximize the utilization of accelerators. A series of experiments is then conducted to derive insights to task synchronization when accelerators might be used.
In distributedreal-time systems, when resource cannot meet workload demand, some jobs have to be removed from further execution. the decision as to which job to remove directly influences the system computation effic...
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ISBN:
(纸本)9781479921133
In distributedreal-time systems, when resource cannot meet workload demand, some jobs have to be removed from further execution. the decision as to which job to remove directly influences the system computation efficiency, i.e., the ratio between computation contributed to successful completions of real-time jobs and total computation contributed to the execution of jobs that may or may not be completed. the paper presents two job removal policies which aim at maximizing system's computation efficiency for distributedreal-time applications where the applications' end-to-end deadlines must be guaranteed. Experiments based on benchmark applications generated by TGFF [1] are conducted and compared with recent work in the literature. the results show clear benefits of the developed approaches - they can achieve as much as 2 0 % computation efficiency improvement.
Embedded control systems such as automotive form large-scale distributed ones which consist of numerous CPUs and devices, including plants and various hardware components. the complexity of such systems has increased ...
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ISBN:
(纸本)9781479944309
Embedded control systems such as automotive form large-scale distributed ones which consist of numerous CPUs and devices, including plants and various hardware components. the complexity of such systems has increased for sophisticated control using numerous types of sensor data. Meanwhile, market pressures lead to reducing development periods for the large-scale distributed embedded control systems. A model-based design becomes popular to solve the above problems, especially automotive industries. In this paper, we describe a wide-area distributed integrated test environment based on the model-based design. the key features are communication middleware to enable wide-area distributed test with integrating the programs in widely distributed sites and control program execution with models of multiple abstraction levels in the model-based design. Furthermore, we developed a model agent simulation. Instead of a plant model that might be located and simulated by MATLAB/Simulink in a remote site, a model agent behaves like the model in a local computer. the model agent simulation significantly reduces the test execution time in a prototype evaluation.
the paper proposes an approach to solve the situation. In our approach, we have developed a middleware component to connect several middleware implementing these object-oriented standard specifications for home comput...
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ISBN:
(纸本)0769515584
the paper proposes an approach to solve the situation. In our approach, we have developed a middleware component to connect several middleware implementing these object-oriented standard specifications for home computing. Actually, our middleware component makes it possible to connect home appliances adopting HAVi, Jini, or UPnP. therefore, various home appliances can communicate with each other.
Fault-tolerant real-time scheduling algorithm is one of the most important means to ensure the timeliness and high availability characteristics of fault-tolerant real-time systems. Existing scheduling models for perio...
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ISBN:
(纸本)9781479921133
Fault-tolerant real-time scheduling algorithm is one of the most important means to ensure the timeliness and high availability characteristics of fault-tolerant real-time systems. Existing scheduling models for periodic real-time task in heterogeneous platforms typically require the number of processors in the systems to be determined in advance;hence prohibit the scalability and the performance of distributed systems. the algorithms based on these models also require a large number of schedubility tests which lead to long execution time. To address these problems, we propose a primary and backup replica partition based fault-tolerant scheduling algorithm (PBPFT) based on a scalable scheduling model using heterogeneity that does not have to determine the scale of the distributed system in advance. the PBPFT approach also takes advantage of backup copy overlapping and phasing delay techniques to minimize system redundancy, and adopts the processor grouping technique to simplify algorithm complexity. Comprehensive experiments are conducted, and the results validate high resource utilization and commendable performance of our proposed approach.
this paper describes an extension to the component-based programming model to support real-time dynamic guarantee for distributed applications. the extended model aims to include an acceptance tests to component-based...
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ISBN:
(纸本)9780769527659
this paper describes an extension to the component-based programming model to support real-time dynamic guarantee for distributed applications. the extended model aims to include an acceptance tests to component-based servers at bind time. We present the mapping of our model to the CORBA component Model, the architecture to support the dynamic guarantee in component-based middleware, the implementation of this architecture in CIAO (component Integrated ACE ORB) and the result of experiments run to evaluate the cost of the mechanisms used.
For distributedreal-time systems, adequate profiling tools are exceedingly rare. the sheer variety and low-level nature of these systems impede the adoption of standard, general-purpose tools for performance analysis...
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ISBN:
(纸本)076952561X
For distributedreal-time systems, adequate profiling tools are exceedingly rare. the sheer variety and low-level nature of these systems impede the adoption of standard, general-purpose tools for performance analysis and visualization. Although much research has been devoted to profiling parallel clusters and supercomputers, the literature virtually ignores the real-time domain. Correspondingly, a handful of commercial tools is available for profiling realtime software, but they invariably make a single-node assumption and are unable to cope withdistributed environments. We examine the state of performance analysis and discuss why profilers are conspicuously absent in the field of distributedreal-time systems. We then explore how developers of these systems could benefit from graphical profiling tools with automatic instrumentation and data collection. Toward that end, we demonstrate the prototype of a performance visualization tool called "Bacara," the second addition to our suite of tools for Visual Analysis of distributedreal-time systems, or VADR (va'dar).
Cyber-physical systems increasingly rely on distributedcomputing platforms where sensing, computing, actuation, and communication resources are shared by a multitude of applications. Such 9;cyber-physical cloud co...
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ISBN:
(纸本)9781479944309
Cyber-physical systems increasingly rely on distributedcomputing platforms where sensing, computing, actuation, and communication resources are shared by a multitude of applications. Such 'cyber-physical cloud computing platforms' present novel challenges because the system is built from mobile embedded devices, is inherently distributed, and typically suffers from highly fluctuating connectivity among the modules. Architecting software for these systems raises many challenges not present in traditional cloud computing. Effective management of constrained resources and application isolation without adversely affecting performance are necessary. Autonomous fault management and real-time performance requirements must be met in a verifiable manner. It is also both critical and challenging to support multiple end-users whose diverse software applications have changing demands for computational and communication resources, while operating on different levels and in separate domains of security. the solution presented in this paper is based on a layered architecture consisting of a novel operating system, a middleware layer, and component-structured applications. the component model facilitates the construction of software applications from modular and reusable components that are deployed in the distributed system and interact only through well-defined mechanisms. the complexity of creating applications and performing system integration is mitigated through the use of a domain-specific model-driven development process that relies on a domain-specific modeling language and its accompanying graphical modeling tools, software generators for synthesizing infrastructure code, and the extensive use of model-based analysis for verification and validation.
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