CEE
597

Risk
Analysis
and
Management
Midterm
2001
Test is open
book
and open notes.
You have 50 minutes to complete this 50 point exam. Show importanlt steps.
1.
(10 points) All this snow
makes
one want
to
get outside. But
Pun
can be dangerous! Consider snow
boarding at a resort with lifts, participating in a toboggan racing team, or playing hockey at a
neighborhood rink such as Cass park in Ithaca. Propose
3
different
quantitative criteria useful
for
colnparinag different aspects of these risks to par~cipants.
In
23 sentences indicate for each criteria
why it is importal~t what dimension
of
risk it emphasizes
in
the comparison, and what it neglects.
2.
(5 points)
In
1900 the death rate in the
US
from cancer was 107/100,000 and ranked
5th
among
the
major killers. However,
in
1990 the death rate from cancer was 1951 100,000 and it ranked
2nd
among
the
major killers!
In
a
short
paragraph, explain
WHY
this
is,
or
is nod
a
reason for alarm. What statistic
would you recornend calculating that would best clarify this issue? What would it show?
3.
(8
points) Consider
;a
system with two independent components
in
series. Assume cornponenl failures
are independent Poisson processes
with
failure rates of
0.01
/month and 0.021 month, respectively.
(a) How long will
this
system Past on average before it fails?
(b)
What is the probability the
system
operatesfor nt least
a
year?
(c) If the engineer decides this system is not sufficiently reliable and adds
a
third
componea~t
with exponential failure rate 0.031 month in parallel with these two, what then is the probabiliq the
expanded system operatesfor
at
least
a
y ~ a r ?
(d)
Draw a fault tree for the systern in (c).
4.
(7 points) Consider the system described by the
nelwor
k:
a)
What are all the mil~imal
cut sets?
b)
If
all elennents are 99.9% reliable, what approximately is the probabiliv the system i d s ?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '07
 Stedinger
 pts, Failure rate, Annualized failure rate

Click to edit the document details