$,'UNIVERSITITEKNOLOGIP ETRONAS

COURSE

DATE

TIME

GAB4O13 - OPERATIONS MANAGEMENT

22nd MAY 2O1O (SATURDAY)

14.30 PM - 17.30 PM (3 hours)

INSTRUCTIONS TO CANDIDATES

1.

2.

3.

4.

5.

Answer ALL questions from the Question Booklet.

Begin EACH answer on a new page in the Answer Booklet.

lndicate clearly answers that are cancelled, if any.

Where applicable, show clearly steps taken in arriving at the solutions and

indicate ALL assumptions.

Do not open this Question Booklet until instructed.

ii.

There are ELEVEN (11) pages in this euestion Booklet

including the cover page and appendix.

Graph papers will be provided.

Universiti Teknologi pETRoNAs

Note :

The time-series model and the causal model are

used in quantitative forecasting approaches. Using

examples, demonstrate the use of each model in

demand for consumer products.

GAB 4013

commonly

appropriate

forecasting

[4 marks]

HomeNeeds Sdn. Bhd. supplies

community. Sales of refrigerators

shown in TABLE Qlb.

refrigerators to the local

over a 10-month period is

TABLE Q1 b

Month Actual Demand

(Units)

January

February

March

April

May

June

July

August

September

October

20

21

28

37

25

29

36

22

25

28

Using exponential smoothing with a = 0.5 and the

forecast for January is 20 units, determine the forecasts

from February through to October.I+t-( --v" [5 marks]

Calculate the mean absolute deviation (MAD). How is the

MAD used when comparing forecast obtained for 2

different values of smoothing constant?

2

[6 marks]

GAB 4013

HomeNeeds Sdn. Bhd. also wants to forecast the demand for air

itioners. Actual demand data collected from sales seems to

an increasing trend as shown in TABLE Q1c.

TABLE QlcMonth Actual Demand

(Units)

August

September

October

19 Lo

23

27

lf the forecast and trend for August was 20 units and 3 units

respectively, and smoothing constants, G = 0.2 and f = 0.4,

calculate the smoothed forecast including smoothed trend for

the months of October and November.

[5 marks]

Fr =), I

1r'-4'

1Y*1t'il

3

2

GAB 401 3

e Explain the components of a linear progrimming (Lp) problem.

\.. Describe wl/o (2) examples on industrial applications of Lp.

' t4 marksl

b. consider the following LP problem of maximizing profit for

products P and Q. Unit profit for products P and e are RM7 and

RM5 respectively.

Objective function: Maximize 7P + 5Q

Subject to: 4P + 3q <240

2P+Q<100

Sketch the graph and indicate the feasible region.

[4 marks]

Calculate the maximum profit that could be obtained from

the products P and Q.

[2 marks]

4

l.- -( llbb

,, | 6ru GAB 4013

c. A company manufactures two models of bathtubs, model A and

model B. Both models require blending of a certain amount of

steel and zinc. 25000 kg of stJel and 6000 kg of zinc are

available for this purpose. Each model A requires a mixture of

125 kg of steel and 20 kg of zinc, and yields a profit of RMg0.

Each model B requires a mixture of 100 kg of steel and 30 kg of

zinc, and yields a profit of RM70. t." ! I r >,g *,10.

loo\ + |'g .(tlo-i. Determine the LP problem formulations.

[5 marks]

ii. Using the LP graphical method, determine the best

production mix of bathtubs.

[5 marks]

Sl.e( +1'nr t

i tt-\I'-+ --

I r-s1l'-I

\

lz,t a,?

)J 6vo

lz!- {1 t ":

3.

e^4 bv 0- t $^*Stt

GAB 4013

AzmiAuto sdn. Bhd. uses 10,000 imported gear assembries each year

(250 working days) in its assembly line. The cost to place and receive

each order is RM50.00 and the demand is constant.

Using the basic Economic Order Quantity (EOO) Model,

determine the economic order quantity and calculate the totar

inventory costs. Annual holding cost is RM2.00 per unit.

[4 marks]

The company is considering making the gear assemblies in-

plant so that dependency on overseas suppliers can be

reduced. The production process is capable of making 60 units

per day. Using the Production Order Quantity Model, determine

the optimum production quantity and the total inventory costs.

[6 marks]

The company has received a discount schedule from a supplier

as shown in TABLE Q3c. Using Quantity Discount Model,

determine the best order quantity and the corresponding total

costs. Annual holding cost is 20 percent of the unit price.

;- u;^

| -. ,{/,U

I tlt/1" i I/a

b.

c.

Irr t ,,lIl- ,' l'- ')

TABLE Q3c

No. Discount QuantityUnit Price

RM

1 O to 749 10.00

2 750 to 799 9.50

3 800 and over 8.90

c

-1 \e

'\ ,,.-t-t L-

[10 marks]

7"/J)/

6

(j

4.

GAB 4013

Maju sdn. Bhd. is a manufacturing company that produces precision

components. Twelve samples, each containing five parts, were takenfrom a process that produces steel rods. The length of each rod in thesamples was determined. The sample means and ranges were

determined and recorded as shown in TABLE e4.Ll ._.

A_ ,

TABLE Q4

Sample Sample Mean (in) Range (in)

1 ,/10.002 0.011 / v2 ,/ 10.002 0.014 /, +3 / 9.991 a.007/ ,,1,4 ,/10.006 0.022 / .l'5 /g.ggt 0.013"/ i6 ,/g.ggg 0.012 ,/ n7 ,/10.001 0.009 ,/-',LB ,/10.005 0.013,/ tfI ,/ Lg95 0.004 ,/ l,10 10.001 0.011

'1.11 10.001 0.0',14 r.12 10.006 0.009 .r

/1 c-oo6 - Q 0.l3B--,1upper and lower control limits for the control

[6 marks]

b( te overall means for the control chart.

[4 marks]

the control chart.

0 0\1r

Drawt\\

q \ What can you deduce about\\-chart? Justify your answer.

the process

[6 marks]

from the control

{ ,{

J-,t/I /t/,/22

7

[4 marks]

GAB 4013

Power Tools Sdn. Bhd. uses soldering equipment in its

production line. The temperature controller of the soldering

equipment has four in-series sensitive integrated circuits

controlling the temperature. The four integrated circuits have

re I i a b i I ity va I ue s gl l?.90, 0,-99. 9 €l a!l! -9.

9 1 respective ty.

b_.t&r[l--L^l:. -^,-.^* -%

It was discovered that the resulting overall reliabirity of the

soldering equipment is inadequate to meet the production line

requirements. To improve the reliability of the soldering

equipment, the supplier has recommended that a redundancy

circuit with reliability of 0.90 be installed to each of the existing

circuits. Determine the reliability of the soldering equipment if

the recommendation is adopted.

[6 marks]

Three units of the improved soldering equipment are going to be

used in a parallel configuration at the company's production line.

Evaluate whether the parallel configuration of the improved

soldering equlpllgltt is able to meet the reliability requirement of

not less than 0.98.

[5 marks]

a5.

b

B

c

GAB 4013

Power Tools sdn. Bhd. employs in-house maintenance staff to

undertake maintenance of the soldering equipment but isconsidering to contract out the maintenance work to the supplier

of the soldering equipment. The contract service will cost power

Tools Sdn. Bhd. RM500 per month.

The supplier has guaranteed that not more than one breakdown

would occur per month should Power Tools Sdn. Bhd. agree to

the maintenance contract. The breakdown data of the soldering

equipments for the last twelve months are as shown in

TABLE QSc. Each breakdown would cost Power Tools Sdn.

Bhd. RM1000.

Evaluate the cost advantage or disadvantage to Power Tools

Sdn. Bhd. when the maintenance service is contracted to the

supplier.

[9 marks]

END OF PAPER -

I

TABLE Q5c

No of

Breakdowns

Number of Months That

Breakdowns Occurred

0

1

2

3

2

4

4

2