35136972
Exact Best-Case End-to-End Response Time Analysis for Hard Real-Time Distributed Systems
The prediction of best-case response time is quite necessary to guarantee control accuracy and stability of distributed hard real-time systems. Published time analysis techniques can precisely dealt with the precedence relations between tasks on different processors, but usually ignored or inaccurately estimated the effects from the precedence relations between tasks on the same processor. This leads to a pessimistic analysis. This paper presents an algorithm to analyze the best-case end-to-end response time for hard real-time distributed systems. This algorithm extends the traditional analysis technique by exploiting the precedence relations between tasks on both different processors and the same processor and achieves a more accurate analysis. Simulation results have shown that this algorithm can achieve more accurate results than existing methods.
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.
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.
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.
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.
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.
42393300
Synchronization between Two Different Hyperchaotic Dynamical Systems Using Nonlinear Control
This paper presents synchronization between two different hyperchaotic systems by nonlinear control laws. First, we introduced hyperchaotic Rossler system and hyperchaotic Chen system, and then synchronization problem between hyperchaotic Rossler system and hyperchaotic Chen system has been investigated. We consider the hyperchaotic Rossler system as the drive system and hyperchaotic Chen system as the response system. Last, Numerical simulations are shown to verify the results.
12761861
A Robust Closed-Loop Control Algorithm for Mean Arterial Blood Pressure Regulation
This paper presents an expert body sensor network (BSN) algorithm for autonomous control of mean arterial blood pressure using vasoactive drugs. A robust Proportional Integral Differential (PID) control algorithm based on a statistics model was designated. Extensive simulation results indicated that the light-weighted expert BSN system is robust enough against sensitivity variations and various artificial disturbances.
32146489
Cycle Period Analysis and Optimization of Timed Circuits
In this paper, a method is proposed to analyze the minimum average cycle period of the timed circuits. Timed Petri net is used to model timed circuits. Our method is focus on structural analysis of the Petri net model of the timed circuits, which is another way to reduce the state space of the analyzed model. Then an algorithm is proposed to optimize the performance of timed circuit by asynchronous retiming technique. The algorithm balances the asynchronous pipelines to gain the target cycle period while minimize the area at the same time. Experimental results demonstrate the computational feasibility and effectiveness of both approaches.
10422931
Chaos Control of Lorenz System Using Small Gain Theorem
This paper studies the problem of controlling chaos in Lorenz system. By dividing Lorenz system into two subsystems, the small gain theorem is used to design linear feedback controllers to make the equilibrium points of the controlled system globally asymptotically stable. Thus chaos in Lorenz system disappears under the controller.
33446676
Voronoi Tessellation Based Rapid Coverage Decision Algorithm for Wireless Sensor Networks
The coverage problem is a fundamental issue in the research of sensor network. A novel Voronoi tessellation based rapid coverage decision algorithm is proposed, in which the region of interest is partitioned into some square grids firstly, and then the complex area coverage problem is transformed into simple vertices coverage problem, on the basis of the good characteristics of Voronoi tessellation such as being able to divide the planner area into a set of simple geometric simplexes. Theoretical analysis and simulation results show that, the new algorithm can decrease the computation complexity of networks, especially for sensor networks with n different sensors, it can solve the coverage problem correctly for any given region of interest with time costs of O(nlogn) only.