99/11/12. When to use it Fig. 1. Fault Tree Analysis in problem solving.

報告：林淇玫老師：洪政煌99/11/12

When to use it

看出錯誤之連環效應找解決之道識別系統風險識別風險如何評估容錯

When to use it

Fig. 1. Fault Tree Analysis in problem solving

Fault Tree Analysis

A graphical tool for representing the relationships among a variety of expected and unexpected events that may contribute to a particular type of system failure.

How to understand it

了解錯誤產生阻止錯誤連環效應發生 (a) an 'and' combination (b) an 'or''

combination. 錯誤架構→階級制度

Fig. 2. Logical And and Or in Fault Tree Analysis


inhibit gate, 預防錯誤產生，除非條件符合 (AND)

Two failure event box: combination events and basic events

basic events ： real root events or may simply not be developed further.

Classic Fault Tree Gates

Name of GateClassic FTA

SymbolDescription

ANDThe output event occurs if all input events occur.

ORThe output event occurs if at least one of the input events occurs.

Voting OR (k-out-of-n)

The output event occurs if k or more of the input events occur.

Classic Fault Tree Gates

Name of GateClassic FTA

SymbolDescription

Inhibit

The input event occurs if all input events occur and an additional conditional event

Priority ANDThe output event occurs if all input events occur in a specific sequence.

XORThe output event occurs if exactly one input event occurs.

Traditional Fault Tree Event Symbols

Primary Event BlockClassic FTA

SymbolDescription

Basic EventA basic initiating fault (or failure event).

External Event (House Event)

An event that is normally expected to occur.

Undeveloped Event

An event which is no further developed. It is a basic event that does not need further resolution.

Conditioning EventA specific condition or restriction that can apply to any gate.


典型降低錯誤發生的方法是建立重複的條件

例子→容錯 FTA 是處理容錯問題有用的工具

How to do it

FTA Procedure

Define the undesired event to study Obtain an understanding of the

system Construct the fault tree Evaluate the fault tree Control the hazards identified

examples

A hospital team An airplane parts manufacturer

References

http://en.wikipedia.org/wiki/Fault_tree_analysis#Analysis(WEB)

Fault Tree Analysis (FTA) Risk Analysis Example-Acupuncture Needles(PDF)

Fault Tree Analysis(PDF) 失效模式及效應分析

Failure Mode & Effects Analysis(PPT) http://syque.com/quality_tools/toolbook/

FTA/fta.htm(WEB) http://www.weibull.com/basics/fault-tre

e/index.htm(WEB)

99/11/12. When to use it Fig. 1. Fault Tree Analysis in problem solving.

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