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Service quality standards is represented by SLA (Service Level Agreement). One way to improve the SLA is to minimize service downtime. This downtime is called with TTR (Time to Repair) which is an FMS (Fault Management System) performance indicator. The lower TTR values, the better the FMS performance. This research discuss the performance improvement by evaluating FMS business process, determine...
Fault trees constitute one of the essential formalisms for static safety analysis of various industrial systems. Dynamic fault trees (DFT) enrich the formalism by time-dependent behavior, e.g., repairs or functional dependencies. Analysis of DFT is so far limited to substantially smaller models than those required for, e.g., nuclear power plants. We propose a fault tree formalism that combines both...
Based on the inertial navigation system of gyro accelerometer “running” accident, DFTA method, through the analysis of the model is established in this paper, static subtree and dynamic subtree analysis for gyro accelerometer “embrace” the accident model and probability of accident. The results found in gyro accelerometer “embrace” the main cause of the accident, used to guide practice, reduce the...
In safety risk research of complex dynamic systems, many methods of improved dynamic system probability risk assessment (PRA) can not be applied widely in the field of engineering because of their limitation; therefore this paper introduces dynamical PRA conception. It studies the expanding of ESD on the base of existing event sequence diagram (ESD) to overcome the deficiency of symbol expressing...
Reliability analysis of phased mission system (PMS) is much more complex, because of the s-dependence across the phases for a given component and the dynamic system structure and configuration which usually requires a distinct model for each phase. After reviewing the modeling method of PMS, the problem of state explosion is put forward. Then the PMS modeling method based on interactive Markov chain...
This paper examines multi-platform phased missions, which involves a number of platforms working together to achieve a common objective. A simulation model for multi-platform phased mission system reliability analysis is proposed. The model simulates the fault processes of various platforms within mission life by using a modularized multi-platform phased mission system model. With the Monte Carlo...
As one of key projects of China at present, the safety of the civil aircraft is a major issue first considered in design and development. Fault-tolerant systems with redundancy are used more often for the design of modern advanced large aircraft. It is a new research area for the safety analysis technology which is not perfect in China. A novel approach to Safety Analysis of Civil Aircraft based on...
Sub systems of complex system or platforms under network centric warfare (NCW) condition are required to work collaboratively in order to achieve an overall mission objective. It is very difficult to model and analyze the reliability of this kind of multiplatform phased mission system (PMS). At first, this paper sums up the characters of multiplatform PMS, and then put forward the method of mission...
The manual development of system reliability models such as fault trees could be costly and error prone in practice. In this paper, we focus on the problems of some traditional dynamic fault trees and present our static solutions to represent dynamic relations such as functional and sequential dependencies. The implementation of a tool for the automatic synthesis of our static fault trees from SysML...
Traditional approaches to handling functional dependence in systems with imperfect fault coverage are based on Markov models, which are inefficient due to the well-known state space explosion problem. Also, the Markov-based methods typically assume exponential time-to-failure distributions for the system components. In this paper we propose a new combinatorial approach to handling functional dependence...
Businesses today are becoming increasingly dependent on information technology (IT) to meet business-critical demands. The more available a computer system is, the more value it can provide to its users. In many cases high availability (HA) requirement becomes as critical as high performance. Cluster computing has been attracting more and more attention from both the industrial and the academic world...
There is a need to quantify system properties methodically. Dependability and security models have evolved nearly independently. Therefore, it is crucial to develop a classification of dependability and security models which can meet the requirement of professionals in both fault-tolerant computing and security community. In this paper, we present a new classification of dependability and security...
The fault tree analysis is a logically structured process that can help identify potential causes of system failure before the failures actually occur. However, traditional fault tree model often suffer from a lack of enough probabilistic basic events to check the consistency of the logic relationship among all events through linkage with gates. Even failures in system operation may have been experienced...
Ring-standby is a type of structure that has been used in complex systems with high reliability requirement. This paper presents a Monte Carlo based reliability evaluation method for this type of structure. The analysis results obtained from this method are compared with those from Markov and Dynamic Fault Tree (DFT) approaches. It is shown that the Monte Carlo simulation can yield additional useful...
System reliability modeling is one of the most important reliability modeling methods for satellite system. Based on the reliability characteristics of satellite system, we used reliability block diagram, fault tree, dynamic fault tree, Markov, and Monte Carlo modeling methods to build reliability models and summarize logic relationships of all kinds of modeling methods, the principle of choosing...
Non deterministic Repairable Fault Trees (NdRFT) are a recently proposed modeling formalism for the study of optimal repair strategies: they are based on the widely adopted Fault Tree formalism, but in addition to the failure modes, NdRFTs allow to define possible repair actions. In a previous pa per the formalism has been introduced together with an analysis method and a tool allowing to automatically...
Special protection systems (SPS) are sometimes perceived by the electric power industry as attractive alternatives to constructing new transmission facilities for maintaining system stability and security. One of the main concerns in the design of SPS is to assure whether the system could fit with the reliability requirements specification. Currently, there are only a few literatures that discuss...
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