ADMS
3351 Fall 2012
Assignment #1
Due at the start
of class
on Tuesday, 23 October 2012
(section B) or Thursday, 25 October 2012 (section A)
Instructions
(please read carefully)
You
may work on this assignment either individually or in pairs (but in the latter case only if you are both enrolled in the same section). If you decide to work with a partner,
one of you musttake
responsibility to send an e-mail to opsmgta@yorku.ca (for section A) or
opsmgtb@yorku.ca (for section B) not later than 5:00 pm on Monday, 15
October 2012, specifying both your full names and student numbers.
Unless I receive such an e-mail by the deadline â receipt of which will
be acknowledgedâ you will have to work on this assignment
individually.
In
either case, you are expected to work independently of other individuals
or pairs. Please review the Senate Policy on Academic Honesty. Penalties
for infractions such as copying of and/or sharing work with other
individuals/pairs will be enforced.Papers will be comparedand
scanned.
Assignments
are to be typed on the computer, except where otherwise specified.
Use 10 or 11 point font, with Times New Roman or Arial for the font type.
Your name(s) and student ID number(s) must be on every page of your
assignment. Pages are to be numbered in a â# of #â format (e.g., page 3 of
10, 7 of 9, etc.). Handwritten assignments will NOT be
accepted/marked.
A cover sheet (in MS Word
format) is posted on the course website â which must be filled in with the
relevant information. You must sign the cover
sheet.
One cover page for
the assignment should be included, not a cover page for each section.
You
may use any available application software (ASW) to determine answers to
the questions on this assignment, but you must cite the ASW used. The ASW
output should be printed out and included as part of the pages of
your assignment.
Assignments
should be organized by question. That means every piece of information for
that question is found in the same section of the report. If we have to
look for certain items while marking, the assignment is not properly
organized.
Assignments
may only be submitted in hard copy. Submission by e-mail is NOT
permitted under any circumstance. Assignments are due at the beginning
of the specified session â in the section in which you are officially
enrolled â as per the course outline. Late assignments will NOT
be accepted/marked.
ADMS 3351 Fall 2012 Page 2
of 6
Assignment
#1
Part
I [20 marks]
DEWEY, MAKEM
& HOWE CONSTRUCTION CO. (A)
Dewey,
Makem & Howe Construction Company [DMHC] builds 2000 ft2
homesâbased upon a standard designâon wooded, half-acre acre lots in a new
development in Peterborough. The major activities involved in producing a
standard home and activity time estimates are as follows.
Immediate
Activity Time
Activity
Description
Predecessors
Estimate (Days)
A
Complete
required documents
–
11
B
Prepare lot
–
8
C
Install
utilities
A, B
4
D
Dig footings
B
3
E
Pour
foundation
D
3
F
Rough plumbing
C, D
7
G
Pour slab
floor
E, F
2
H
Frame up house
G
17
I
Wire house
H
6
J
Frame up roof
H
4
K
Finish
plumbing
G
6
L
Shingle roof
I, K
5
M
Outside
insulation
H, K
3
N
Install
windows and outside doors
H
5
O
Install siding
M, N
6
P
Insulate walls
and ceilings
J, K, N
3
Q
Finish
exterior
L, O
18
R
Install
wallboard
P
5
S
Landscape lot
Q
5
T
Finish
interior
R
15
U
Insulate roof
I, R
6
Questions:
Draw an AON network diagram either by hand or
using some drawing facility on the computer if you prefer doing so. Your
diagram must clearly show all given activities and
precedence relationships â and must follow the conventions we discussed in
class for drawing project networks.
Determine
the earliest and latest start/finish times for each activity.
Which
activities are critical? Specify the critical path(s).
Indicate
[graphically, using double/bold arrows or a different color on each arc]
the critical path(s) on your network diagram.
What is the
expected project completion time for a standard home?
ADMS 3351 Fall 2012 Page 3
of 6
Assignment
#1
Which
activity or activities can be delayed the longest (and by how many days at
the most) without delaying completion of the entire project?
Part
II [25 marks]
DEWEY, MAKEM
& HOWE CONSTRUCTION CO. (B)
The
weather and building material delivery leadtimes are occasionally a problem, so
the DMHC Construction Project Manager has come up with optimistic, most likely,
and pessimistic time estimates of how long it actually takes to complete each
of the previously specified activities.
Activity
Activity Time
Estimates (Days)
Optimistic
Most Likely
Pessimistic
A
6
11
16
B
5
8
11
C
3
4
6
D
2
3
5
E
2
3
4
F
6
7
9
G
1
2
4
H
13
17
23
I
4
6
9
J
3
4
5
K
5
6
7
L
4
5
7
M
2
3
4
N
3
5
7
O
5
6
7
P
2
3
5
Q
12
18
24
R
4
5
6
S
4
5
8
T
12
15
21
U
5
6
8
Questions:
Assuming
a beta probability distribution, report the mean and standard deviation of
completion time for each activity?
Is
there any change in the critical path(s) as a result of the introduction
of three time estimates for each activity?
The Sales Manager wishes to
offer an incentive of 10% off the selling price of the standard home if
DMHC cannot complete the job in 77 working days or less. Will the
ADMS 3351 Fall 2012 Page 4
of 6
Assignment
#1
Sales
Manager’s proposed incentive be appropriate for DMHC to offer its customers?
Explain why or why not.
Suggest completion times (in
number of full working days; e.g., 77 working days) to the Sales Manager
such that he would have to âpayâ the incentive not more than
9% of the time, 5% of the time, or 1% of the time.
Part
III [20 marks]
YorkTek
wishes to assemble 220 units of an electronic product per hour, with 55 minutes
per hour that are actually productive. The following tasks, with corresponding
task times, are required to assemble each unit:
Tasks That
Time to
Immediately
Perform Task
Task
Precede
(minute)
A
–
0.25
B
A
0.08
C
B
0.12
D
B
0.17
E
C, D
0.06
F
E
0.05
G
E
0.09
H
E
0.11
I
F, G, H
0.16
J
I
0.08
Questions:
Draw
a diagram of the precedence relationships either by hand or using some
drawing facility on the computer if you prefer doing so.
Compute the
cycle time per unit in minutes.
Compute the
theoretical minimum number of workstations required.
Use the
longest-task-time heuristic to balance the production line.
Evaluate
the efficiency of your solution.
ADMS 3351 Fall 2012 Page 5
of 6
Assignment
#1
Part
IV [20 marks]
iSell,
Inc.
iSell,
which started out years ago as a telephone merchandising operation, has
developed into alarge e-business operation. Nonetheless, iSell
continues to accept orders by telephone (800 – PHONEIN) from customers all over
Canada. It currently has a total of 20 Telephone Sales Representatives
(TSRs) available during Saturday peak hours. When all TSRs are busy serving
customers, an incoming call is answered by a recorded message asking the caller
to hold his/her line, and giving the assurance that the call will be attended
to in the order it came in. Most customers, however, are usually not willing to
be put on hold for too long.
During
peak hours on Saturdays, customer calls come in at an average rate of 165 calls
every half hour, following a Poisson distribution. It takes a TSR an average of
3 minutes and 36 seconds to service a customer, with the service times being
observed to be follow a negative exponential distribution.
At
a recent operations meeting, iSell’s management team decided, in line
with its desire to provide customer service at the best possible level (without
placing undue strain on the companyâs telephone system), to seek to achieve the
following operational performance objectives:
more than 30 seconds waiting for a TSR. [2] The average number of customer
calls in the queue should not be more than 10.
[3] The total number of
customer calls in the system (both being attended to and on hold) exceeds 30
not more than 12% of the time.
Questions:
Are the 20 TSRs
adequate to handle customer calls during Saturday peak hours, based on all
three operational performance objectives? Explain your answer citing
appropriatefigures from your ASW printouts.
If
your answer to(A) is no,
how many TSRs should the company employ duringSaturday peak hours
to achieve the first two performance objectives? Justify the number
of TSRs you specify. [Bear in mind that employing more TSRs than are
required will cost the company more. Hence, you should specify the minimum
number of TSRs that would satisfy the policies.You must
also establish that any less TSRs than you choose to employ would
not satisfy those two policies.]
Fully
explain/establishwhether or not
objective (iii) is achieved with the number ofTSRs you
choose to employ. Explain your answer by using appropriate figures from
your ASW printouts.
ADMS 3351 Fall 2012 Page 6
of 6
Assignment
#1
Part
V [15 marks]
A
manufacturing firm produces a certain item to a fairly high degree of
precision. In the statistical process control for the item, five units are
randomly selected from the output every hour. In the attached file (24hrs.xls),
the measurements are recorded sequentially for the samples over the previous 24
hours of operation.
Create
(1) an x-bar chart and (2) an R chart from the given sample data using
3-sigma control limits. Make sure that you show your calculations of the
central line and the upper and lower control limits for each control
chart.
Comment
on whether or not the process is in control, based upon the patterns
presented in Exhibit 7.12 of our textbook.
