Production Control - Operations research and Operations management - Production & Industrial Engineering Previous Year Questions

1

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

Which one of the following is an indispensable part of Just-in-Time manufacturing of multiple products on a line?

A

Outbound quality inspection

B

Lot sizing

C

Safety stocks

D

Set up time reduction

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2

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

The moving average method is to be used for forecasting demand based on \( m \) periods of data. Two values of \( m \) are tried, \( m_1 \) and \( m_2 \) with \( m_1 > m_2 \), to get two different forecasts, denoted by \( F(t) \) and \( G(t) \).
P – \( F(t) \) has less variability than \( G(t) \)
Q – Forecast error of \( F(t) \) is less than that of \( G(t) \)
Which of the above statements are true?

A

Only P

B

Only Q

C

Both P and Q

D

Neither P nor Q

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3

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

The moving average method is to be used for forecasting demand based on m periods of data. Two values of m are tried, m_1 and m_2 with m_1 > m_2, to get two different forecasts, denoted by F(t) and G(t).
P – F(t) has less variability than G(t)
Q – Forecast error of F(t) is less than that of G(t)
Which of the above statements are true?

A

Only P

B

Only Q

C

Both P and Q

D

Neither P nor Q

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4

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

Item P is made from components Q and R. Item Q, in turn, is made from S and T. The lead times for items P, Q, R, S, and T are 2, 3, 10, 5, and 6 weeks, respectively. The lead time (in weeks) needed to respond to a customer order for item P is

A

10

B

11

C

12

D

26

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5

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

Four jobs have to be sequenced on a single facility, with the objective of minimizing the maximum tardiness \(= \max_j |\text{Completion time}_j - \text{Due date}_j|\). The jobs have due dates and processing times as follows.

Job	Due date (day number)	Processing time (days)
P	5	2
Q	6	10
R	3	3
S	7	4

The last job that should be taken up is

A

P

B

Q

C

R

D

S

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6

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

A manufacturing system with a production rate \(p\) units/day experiences a demand rate of \(d\) units/day where \(p > d\). Let \(Q\) be the maximum production quantity per period. When the total production in a period reaches \(Q\) units, the production is stopped and restarted only when inventory becomes zero. In such a scenario, the maximum cycle inventory is

A

\(Q \cdot p \cdot (p - d)\)

B

\(\frac{Q}{(p - d)} p\)

C

\(\frac{Q}{p} (p - d)\)

D

\(\frac{p(p - d)}{Q}\)

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7

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

The minimum WIP level that allows the line to operate under maximum capacity is

A

1.7

B

4.0

C

6.8

D

8.6

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8

2007 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2007

Statement for Linked Answer Questions 78 & 79:
Consider an unbalanced serial assembly line consisting of three workstations that produces a single part. The part visits each workstation exactly once. The number of parallel machines at each workstation and the processing time at a machine is shown below:

Workstation	Number of machines	Processing time (minutes)
1	1	2
2	2	5
3	6	10

What is the capacity (in parts/minute) of the above assembly line?

A

0.1

B

0.4

C

0.5

D

0.6

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9

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

In inventory cost structure, set up cost is a part of replenishment cost when it

A

has taken place externally

B

is dependent on supply conditions

C

is independent of supply conditions

D

has taken place internally

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10

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

The process of tracing through the MRP records and all levels in the product structure to identify how changes in the records of one component will affect the records of other components is known as

A

product explosion

B

lead time offsetting

C

updating

D

pegging

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11

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

When P is the rate of production, D is the demand rate and t is the duration of production, the actual inventory built up during production period in the EPQ model is

A

Zero

B

(P+D)t

C

Pt

D

(P-D)t

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12

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

Six jobs are received for processing and their processing times and delivery dates are given below:

Job Sequence	Production Time (days)	Delivery Date (days)
P	2	4
Q	5	18
R	3	8
S	4	4
T	6	20
U	4	24

Using FCFS dispatching rule, the average lateness is

A

2.0

B

1.5

C

1.0

D

0.5

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13

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

Daily demand of a product is normally distributed with a mean of 50 units and a standard deviation of 5. Supply conditions are virtually certain with a lead time of 6 days. If a 95 percent service level is desired, the reorder point ($z_{0.95}=1.645$) is

A

340 units

B

320 units

C

300 units

D

280 units

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14

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

Statement for Linked Answer Questions 84 and 85:
A company forecasts the demand for a product to be 400 units per month for each of the next three months. The actual demand, however, turned out to be 400, 550 and 580 units respectively for those three months.
The forecast error bias is

A

-330 units

B

-110 units

C

110 units

D

330 units

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15

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

Statement for Linked Answer Questions 84 and 85:
A company forecasts the demand for a product to be 400 units per month for each of the next three months. The actual demand, however, turned out to be 400, 550 and 580 units respectively for those three months.
The forecasting technique used has a tendency to

A

under forecast with 21.56% bias

B

over forecast with 21.56% bias

C

under forecast with 64.70% bias

D

over forecast with 64.70% bias

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16

2008 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2008

The forecasting technique used has a tendency to

A

under forecast with 21.56% bias

B

over forecast with 21.56% bias

C

under forecast with 64.70% bias

D

over forecast with 64.70% bias

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17

2009 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2009

Which of the following forecasting models explicitly accounts for seasonality of demand ?

A

Simple moving average model

B

Simple exponential smoothing model

C

Holt’s model

D

Winter’s model

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18

2009 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2009

A grocery store faces a demand of 50 units of soap per day. The store orders soap periodically. It costs Rs.100 to initiate a purchase order. It costs Rs. 0.04 per soap per day to store the soap. The lead time between placing and receiving the order is 4 days. The optimal inventory policy for ordering soap is to

A

order 500 units of soap whenever inventory level drops to 200 units

B

order 500 units of soap whenever inventory level drops to 100 units

C

order 1000 units of soap whenever inventory level drops to 200 units

D

order 1000 units of soap whenever inventory level drops to 100 units

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19

2009 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2009

The optimal sequence of jobs that will minimize makespan (total time required to complete all jobs) is

A

I - II - III - IV

B

III - II - I - IV

C

IV - III - I - II

D

III - I - IV - II

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20

2009 · Production & Industrial Engineering · Operations research and Operations management · Production Control

Production & Industrial Engineering (PI) 2009

When the jobs are processed based on the optimal sequence that minimizes makespan, the total idle time (in min) on Machine N is

A

1

B

3

C

4

D

6

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