Class Notes (808,131)
GMS 401 (277)
Lecture

# 4S notes.docx

4 Pages
158 Views

School
Ryerson University
Department
Global Management Studies
Course
GMS 401
Professor
Kirk Bailey
Semester
Fall

Description
4S Reliability: probability that an item will function as intended  if something functions as intended 90% of the time p=.90  if something fails 10% of the time p=.10  functions+fails must = 1.0 ex: 3 components with reliabilities of .7 .4 and .3  Overall reliability is .7*.4*.3=.084  Therefore one or more fail .916 of the time (1-.084) Improving Reliability:  Use better components  Use better manufacturing techniques  Use REDUNDANT backup components (cheaper and more expensive) Ex: spare tire on car Reliability with redundant backup:  Reliability=.85 failure=.15  Backup with 100% reliability = .85+.15*.85=.9775 (failure*success+success=reliability with redundant backup)  .85=item works, .15=item fails, resulting in .9775 improvement with backup Ex: A system of 3 components with reliabilities .90, .85, .70(.90*.85*.70 = .5355) only one can be backed up  .90 component, leaving the .85 and the .70 alone  (.90 + .10*.90) *.85*.70 = .5891  .85 component, leaving the .90 and the .70 alone  .90 * (.85 + .15*.85) * .70 = .6158  .70 component, leaving the .90 and the .85 alone  .90*.85*(.70 + .30*.70) = .6962  Therefore, backup .60 component More space for backups:  Backup weakest component followed by the next weakest one  If the strongest one is backed up it would not result in much improvement in reliability as those components are more likely to NOT fail Failure rates over time  All components fail over time due to repeated usage  As components wear out, they form patterns 
More Less

Related notes for GMS 401

OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Join to view

OR

By registering, I agree to the Terms and Privacy Policies
Just a few more details

So we can recommend you notes for your school.