18111881
Worst-Case Response Time Analysis for OSEK/VDX Compliant Real-Time Distributed Control Systems
Temporal behaviors prediction is very critical for real-time control systems. This paper presents a method to analysis the worst-case response time of OSEK/VDX compliant hard real-time distributed control systems. OSEK/VDX is an industry standard for an open-ended architecture for distributed control units in vehicles. Traditional time analysis methods based on the fixed priority preemptive scheduling model do not account for the problems occur in practical systems. Based on the current time analysis technologies, we propose an accurate time analysis method considering the practical effects of resource access synchronization, mixed preemptive and non-preemptive scheduling, as well as the overheads of OSEK OS. Furthermore, we also propose a scheme to efficiently integrate time analysis tools into the current development process for electronic control units in vehicles.
5460989
End-To-End Worst-Case Response Time Analysis for Hard Real-Time Distributed Systems
The verification of end-to-end response time for distributed hard real-time systems is quite necessary for safety-critical applications. Although current time analysis techniques can precisely analyze the response time, the performance is not quite satisfying, especially for large size distributed systems. This paper presents a novel end-to-end worst-case response time analysis approach for hard real-time distributed systems. This technique is based on the critical instant analysis and the canonical form transformation. It extends the traditional holistic analysis technique by exploiting the precedence relations between tasks on both different processors and the same processor. Simulation results have shown that this algorithm can achieve accurate results and offers good performance for systems with wide range of CPU utilizations and task set size, and therefore is applicable to schedulability analysis of complex distributed systems.
28662296
A Service Oriented Implementation of Distributed Status Monitoring and Fault Diagnosis Systems
The service-oriented architecture (SOA) can greatly improve the collaboration of devices in a distributed environment. With this architecture, human can be liberated from the burdensome configuration and management of distributed systems, especially when the nodes of the systems are dynamically changed. In this paper, we present a method to implement service-oriented distributed systems in industry. As a case study, we present a service-oriented Status Monitoring and Fault Diagnosis Systems (SMFDS) for large equipment. Our work is based on the UPnP (Universal Plug and Play) technology. Through abstracting the interfaces of devices and providing service middleware in an independent thread or process, the SOA can be easily implemented on an existing system with the least modifications. This characteristic is very useful when upgrading an existing system, for cost and risk consideration.
9201590
A Reliable OS Kernel for Smart Sensors
17996623
Fault tolerant scheduling for fixed-priority tasks with preemption threshold
Fixed-priority with preemption threshold (FPPT) is an important form of real-time scheduling algorithm, which fills the gap between fixed-priority preemptive (FPP) and fixed-priority non-preemptive (FPNP). However, this scheduling scheme together with the requirements of fault tolerance makes the prediction of a real-time system's behaviors more difficult than traditional scheduling scheme. The major contribution of this work is twofold. First, we present an appropriate schedulability analysis, based on response time analysis, for supporting fault-tolerant FPPT scheduling in hard real-time systems. The error-recovery techniques are considered to be used to carry out fault tolerance. Second, we propose the optimal priority assignment algorithm which can be used, together with the schedulability analysis, to improve system fault resilience.
206594316
An OSEK COM Compliant Communication Model for Smart Vehicle Environment
Smart Vehicle Environment (SVE) is an important application of the idea of smart spaces. This paper presents Smart Vehicle Multi-Agent System (SVMAS) to achieve the goal of SVE and put forwards a commutation model for SVMAS based on SmartOSEK COM [1] to support data exchange. The paper also presents an approach to encapsulate the message to transport by CAN bus, and bring forward a simulator model for SVMAS. Finally the paper gives an example of the communication model which implements a dialogue between two agents and analyzes the performance. The contribution of our work is threefold. First, we adopt Knowledge Query and Manipulation Language (KQML) to describe the communication in vehicles. Second, we develop SmartOSEK COM to implement communication in vehicles. Third, we define the ACLcan protocol to transform the message from SmartOSEK COM to CAN frame.
5365763
An extended approach to improving the semantic interoperation among reuse epositories
Software reuse is widely believed as a feasible way to improve both the productivity and quality of software development. The developers must be capable to acquire enough desired components before developing with reuse. Many Internet-enabled reuse repositories exist to provide access to reusable resources. It is necessary to eliminate the semantic gaps of the repositories to enable users to access resources from multiple repositories via a single representation view. In some sense, the only usable information to mine the semantics of the terms representing the resources is the mutual components stored in the repositories. In this paper, the extended improved relevancy matching and ranking (EIRMR) method is proposed to enhance the semantic interoperability of reuse repositories, based on our previous work (IRMR) and the mutual components in the third-party repositories. Experimental results on the data sets from the real repositories demonstrated an improvement in terms of searching effectiveness.
15780361
The Real-Time Networked Data Gathering Systems Based on EtherCAT
Distributed control systems have been growing explosively and the Fieldbus technology has been widely employed for networked data gathering system. However, few Field-bus is real time down to the I(Input)/O(Output) level and most of them have a large number of sub-systems. In this paper we introduce a novel high-speed industry Ethernet bus known as EtherCAT into data gathering system. A networked data gathering system based on EtherCAT is achieved and the experimental results indicate the system can perform well in real-time data transmission.
13024197
Joint Performance Improvement and Error Tolerance for Memory Design Based on Soft Indexing
Memory design is facing the dual challenges of performance improvement and error tolerance due to a combination of technology scaling and higher levels of integration. To address these challenges, we propose a new memory microarchitecture referred to as the soft indexing. The proposed technique allocates memory resources in a self-adaptive manner in accordance with runtime program variations, thereby achieving efficient memory access and effective error protection in a coherent manner. Statistical analysis shows 10times improvement in error detection capability over the existing error-control techniques. The benefits of the proposed technique are also experimentally demonstrated using the SPEC CPU2000 benchmarks. Simulation results show 94.9% average error-control coverage on the 23 benchmarks, with average of 23.2% reduction in memory miss rates as compared to the conventional techniques.
27036823
A new method in multi-issue negotiation
In this paper we describe a mechanism for automated negotiation in which artificial agents can deal with a multiissue negotiation in a one-to-many way based on some strategies. The negotiation process are governed dynamically by some strategies that emphasize on the diverse processing methods under the considering of different commodity attributes, including dynamic delayed evaluation and response to the received offers, generation of offer group with the same utility. Our analysis shows that the mechanism ensures that bargaining agents could reach a better agreement automatically. We also implement a prototype system to verify the advantages of our mechanism
3919925
Calculation of Loss Probability in a Finite Size Partitioned Buffer for Quantitative Assured Service
This paper proposes an approximate yet accurate approach to calculate the loss probabilities in a finite size partitioned buffer system for the achievement of a quantitative assured service in differentiated services networks. The input is modeled as a fractional Brownian motion (FBM) process including J classes of traffic with different packet loss requirements. A first-in first- out buffer partitioned with J-1 thresholds is used to provide J loss priorities. Heuristic expressions of the loss probabilities for all the J classes are derived, and validated by computer simulations. The proposed loss calculation technique is then extended to a general input process by using the recently proposed traffic substitution technique, where both long-range dependent and short-range dependent input sources are equivalent to a properly parameterized FBM. We also apply the loss calculation to admission control, where the partition thresholds are optimally configured for quality of service guarantee and maximal resource utilization. Computer simulation results demonstrate that resource allocation based on the accurate finite buffer loss analysis results in much more efficient resource utilization than that based on the classic large-buffer overflow approximation.