Exam 13: Simulation Modeling

The wider the variation among results produced by using different sets of random numbers,the longer we need to run the simulation to obtain reliable results.

List the major disadvantages of simulation techniques.

The process of comparing a model to the real system that it represents to make sure it is accurate is called

One of the major advantages of simulation is "time compression," i.e. ,the ability to study in a relatively short period,activities that would,in reality,take place over a period of days,months,or even years.

To "simulate" is to try to duplicate the features,appearance,and characteristics of a real system.

The demand for refrigerators at an appliance store adheres to the following probability distribution: The store orders 4 refrigerators per day to have in stock to meet demand.They are trying to maintain low inventory levels.The holding cost is $5/unit/day.The ordering cost is $20 per order.The lost sale cost is $10/unit.A simulation is to be developed to estimate the average daily inventory cost over 5 days.The table below shows the random numbers to be used for refrigerator demand and lead time on orders: Assuming that beginning inventory is equal to 5 with no prior orders in transit,what is the overall average daily cost of inventory for the 5 days?

Explain what is meant by operational gaming and give one example.

Simulation models are designed to generate optimal solutions,which can then be applied to real-world situations.

Table 13-3 A pharmacy is considering hiring another pharmacist to better serve customers.To help analyze this situation,records are kept to determine how many customers will arrive in any 10-minute interval.Based on 100 ten-minute intervals,the following probability distribution has been developed and random numbers assigned to each event. -According to Table 13-3,the number of arrivals in any 10-minute period is between 6 and 10,inclusive.Suppose the next three random numbers were 20,50,and 79,and these were used to simulate arrivals in the next three 10-minute intervals.How many customers would have arrived during this 30-minute time period?

Validation relates to building the right model.

When establishing a probability distribution based on historical outcomes,the relative frequency for each possible outcome of a variable is found by dividing the frequency of each outcome by the total number of observations.

Which of the following variables are probabilistic in an inventory model that requires simulation?

One disadvantage of simulation is that it does not allow for "what-if?" types of questions.

Describe the conditions when simulation is useful for queuing analysis.

Which of the following represents the primary reason simulation cannot be used for the classic EOQ model?

Table 13-5 -According to Table 13-5,which presents a summary of the Monte Carlo output from a simulation of 200 runs,there are 5 possible values for the variable of concern.If this variable represents the number of machine breakdowns during a day,what is the probability that the number of breakdowns is 2 or fewer?

The time between arrivals at a drive-through window of a fast-food restaurant follows the distribution given below.The service time distribution is also given in the table below.Use the random numbers provided to simulate the activity of the first five arrivals.Assume that the window opens at 11:00 a.m.and the first arrival after this is based on the first interarrival time generated. Random numbers for arrivals: 14,74,27,03 Random numbers for service times: 88,32,36,24 What times does the fourth customer leave the system?

A major advantage of using simulation techniques is to be able to study the interactive effect of individual components/variables.

Table 13-3 A pharmacy is considering hiring another pharmacist to better serve customers.To help analyze this situation,records are kept to determine how many customers will arrive in any 10-minute interval.Based on 100 ten-minute intervals,the following probability distribution has been developed and random numbers assigned to each event. -According to Table 13-3,the number of arrivals in any 10-minute period is between 6 and 10 inclusive.Suppose the next 3 random numbers were 02,81,and 18.These numbers are used to simulate arrivals into the pharmacy.What would the average number of arrivals per 10-minute period be based on this set of occurrences?

If,in a simple queuing or waiting line problem,we wish to know the maximum likely waiting time,or the maximum likely length of the line,we must use a simulation model.