This document discusses duty cycle concepts in reliability engineering. It begins with definitions of time-based and stress-condition-based duty cycles. Time-based duty cycle is the proportion of time a system is active, while stress-condition-based duty cycle considers the level of stress applied. The document then discusses how duty cycle manifests differently across various industries and how it is used to calculate reliability, with duty cycle affecting mission time, failure mechanisms, and characteristic life. Examples are provided for hard disk drives to illustrate the effects of duty cycle on acceleration factors and mean time to failure.
Commonly used maintenance strategies vary from simple ones such as Corrective Maintenance (CM), which is performed upon system failure, to Preventive Maintenance (PM) where maintenance actions are taken at scheduled time intervals. Both strategies, however, have limitations. Recent advances in sensors, control systems, software engineering, and communication technology have prompted manufacturers to move towards the condition monitoring of system health. Maintenance is performed based on the observed system condition, which is referred to as Condition-Based Maintenance (CBM). This presentation gives a comprehensive introduction to CBM, and introduces a method for CBM scheduling for systems with multiple failure modes. It is observed in some applications that the hazard rate corresponding to each failure mode depends on both time and system state. The system state stochastically degrades, and the degradation rate is often a function of time and the degradation level at that particular time. A maintenance alarm is used to signal when the degradation reaches a threshold value. A new joint model is developed for the stochastically dependent time-to-maintenance due to system degradation and time-to-failure of different failure modes. The model is then utilized to obtain the optimum threshold value that maximizes the system’s availability over its life cycle, or, minimizes the long-run cost per unit time. A illustrative example, using real-life data from a reliability test of communication systems, is provided to demonstrate the application of the approach.
This document discusses duty cycle concepts in reliability engineering. It begins with definitions of time-based and stress-condition-based duty cycles. Time-based duty cycle is the proportion of time a system is active, while stress-condition-based duty cycle considers the level of stress applied. The document then discusses how duty cycle manifests differently across various industries and how it is used to calculate reliability, with duty cycle affecting mission time, failure mechanisms, and characteristic life. Examples are provided for hard disk drives to illustrate the effects of duty cycle on acceleration factors and mean time to failure.
Commonly used maintenance strategies vary from simple ones such as Corrective Maintenance (CM), which is performed upon system failure, to Preventive Maintenance (PM) where maintenance actions are taken at scheduled time intervals. Both strategies, however, have limitations. Recent advances in sensors, control systems, software engineering, and communication technology have prompted manufacturers to move towards the condition monitoring of system health. Maintenance is performed based on the observed system condition, which is referred to as Condition-Based Maintenance (CBM). This presentation gives a comprehensive introduction to CBM, and introduces a method for CBM scheduling for systems with multiple failure modes. It is observed in some applications that the hazard rate corresponding to each failure mode depends on both time and system state. The system state stochastically degrades, and the degradation rate is often a function of time and the degradation level at that particular time. A maintenance alarm is used to signal when the degradation reaches a threshold value. A new joint model is developed for the stochastically dependent time-to-maintenance due to system degradation and time-to-failure of different failure modes. The model is then utilized to obtain the optimum threshold value that maximizes the system’s availability over its life cycle, or, minimizes the long-run cost per unit time. A illustrative example, using real-life data from a reliability test of communication systems, is provided to demonstrate the application of the approach.
52. Open Data 應用-資料新聞學
資料新聞學是可利用 Data 或 Open
Data,經由 Open Source 或統計軟
體做數據分析,報導更實際的新聞
與事實來幫助社會。
資料新聞學是指,透過對大量資料
集進行分析與篩檢後,來產出新聞
報導(故事)的一種新聞處理程序。
(wiki)
53. Open data 成果之一 萌典
» 收錄十六萬筆國語、兩萬筆台語條目,不需網路連線即可檢閱。
» 有網路連線時可播放國語常用條目、台語條目名稱的真人發音。
» 定義裡的每個字詞都可以輕按連到說明。
54. Open data 成果之一 萌典
萌典(Web)
https://www.moedict.tw/
萌典(Android)
https://play.google.com/store/apps/details?id=org.audrey
t.dict.moe
萌典(iOS)
https://itunes.apple.com/tw/app/meng-dian/id599429224
反查來源:教育部國語辭典:
http://dict.revised.moe.edu.tw/cgi-
bin/newDict/dict.sh?idx=dict.idx&fld=1&imgFont=1&cat&con
d=%5E%B5%DE%24&x=32&y=40