Case 17-2 Remembering September 11

Adeline Jonasson lost two close friends in the collapse of the World Trade Center on September 11, 2001. Both had been vibrant young women who left grieving husbands and children behind. What terrible losses. Even now, many years later, not a day goes by that she doesnt think of these friends and feel the anger yet again over those senseless deaths. She still feels a real sense of mission to do something about it. What a relief it had been to be offered a top managerial position in the Transportation Security Administration. After being told that the job would

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involve heading a task force on airport security, Adeline had not hesitated a moment in accepting the position. She had greatly enjoyed her career as a management science consultant in the airline industry. It was very satisfying to help several airline companies save many millions of dollars. However, she now felt a greater calling. She would be able to use her expertise in management science to help save lives. There was no way to bring her friends back, but at least she could do everything possible to prevent this from happening again.

Adeline is indeed in the right spot to carry out her mission. Shortly after the tragic events of September 11, 2001, the United States Congress enacted emergency legislation to give the Department of Transportation primary responsibility for providing security at over 400 major U.S. airports. The Transportation Security Administration was then created within the Department of Transportation to carry out this responsibility. One assignment given to Adelines task force is to investigate what advanced security technology should be developed and used at airport checkpoints to maximize the effectiveness with which passengers can be screened within budget constraints.

Even prior to 2001, airline passengers had become familiar with the two basic types of systems used to check each passenger at a security checkpoint. One is a portal that can detect concealed weapons as the passenger walks through. The other is a screening system that scans the passengers carry-on luggage. Various proposals have been made for advanced security technology that would improve these two systems. Adelines task force now needs to make recommendations on which direction to go for the next generation of these systems.

The task force has been told that the functional requirement for the new portal system is that it must be able to detect even one ounce of explosives and hazardous liquids as well as metallic weapons being concealed by a passenger. The technology needed to do this includes quadrupole resonance(closely related to magnetic resonance technology used by the medical industry) and magnetic sensors. There are various ways to design the portal with this technology that would satisfactorily meet the functional requirement. However, the designs would differ greatly in the frequency with which false alarms would occur as well as in the purchase cost and maintenance cost for the portal. The frequency of false alarms is a key consideration since it substantially affects the efficiency with which the passengers can be processed. Even more importantly, a high frequency of false alarms greatly decreases the alertness of the security personnel for detecting the relatively rare terrorists who are actually concealing destructive devices.

The most basic version of the portal system that satisfactorily meets the functional requirement has an estimated purchase price of $ 90,000 and, on the average, would incur an annual maintenance cost of $15,000. The drawback of this version is that it would generate a false alarm for approximately 10 percent of the passengers. This false alarm rate can be reduced by using more expensive versions of the system. Each additional $15,000 in the cost of the portal system would lower the false alarm rate 1 percent and also would increase the annual maintenance cost by $1,500. The most expensive version would cost $210,000, so it would have a false alarm rate of only 2 percent of the customers as well as an annual maintenance cost of $27,000.

Regarding the new screening system for carry-on luggage, the functional requirement is that it must clearly reveal suspicious objects as small as the smallest Swiss army knife. The technology needed to do this combines X- ray imaging, a thermal neutron scanner, and computer tomography imaging (which compares the density and other physical properties of any suspicious objects with known high-risk materials). It is estimated that the most basic version that satisfactorily meets this functional requirement would cost $60,000 plus an annual maintenance cost of $9,000. As with the most basic portal system, the drawback of this version is that it doesnt sufficiently discriminate between suspicious objects that actually are destructive devices and those that are harmless. Thus, this version would generate false alarms for approximately 6 percent of the customers. In addition to wasting time and delaying passengers, such a high false

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alarm rate would make it very difficult for the screening operator to pay sufficient attention when the far more unusual true alarms occur. However, more expensive versions of the screening system would be considerably more discriminating. In particular, each additional $30,000 in the cost of the system would enable a reduction of 1 percent in the false alarm rate, while also increasing the annual maintenance cost by $ 1,200. Thus, the most expensive version, costing $150,000, would decrease the false alarm rate to 3 percent and incur an annual maintenance cost of $12,600.

The task force has been given two budgetary guidelines.

First budgetary guideline: Plan on a total expenditure of $250,000 for both the portal system and the screening system for carry-on luggage at each security checkpoint.

Second budgetary guideline: Plan on holding down the average total maintenance costs for the two systems at each security checkpoint to no more than $30,000.

These budgetary guidelines prohibit using the most expensive versions of both the portal system and the screening system for carry-on baggage. Therefore, the task force needs to determine which financially feasible combination of versions for the two systems will maximize the effectiveness with which passengers can be screened. Doing this requires first obtaining input from the top management of the Transportation Security Administration regarding what the measure of effectiveness should be and then what managements goals and priorities are for achieving substantial effectiveness and meeting the budgetary guidelines.

Fortunately, Adeline already has had extensive discussions with top management to obtain its guidance on these matters. These discussions led to the adoption of a clear policy that was approved all the way up to the Secretary of Transportation (who also informed the chairpersons of the congressional oversight committees of this action). The policy establishes the following order of priorities.

Priority 1: The functional requirement for each of the two new systems must be met. (This is satisfied by all the versions under consideration by the task force.)?

Priority 2: The total false alarm rate for both systems should not exceed 0.1 per passenger.

Priority 3: Meet the first budgetary guideline.

Priority 4: Meet the second budgetary guideline.

Now that it has obtained all the needed managerial input, the task force is ready to begin its analysis.

Identify the two decisions to be made and define a decision variable for each one.

Describe why this problem is a preemptive goal-programming problem by giving quantitative expressions for each of the goals in terms of the decision variables defined in part a.

Draw a single two-dimensional graph where the two axes correspond to the decision variables defined in part a. Consider each of the goals in order of priority and use the quantitative expression obtained in part b for this goal to draw a plot on the graph that displays the values of the decision variables that fully satisfy this goal. After completing this for all the goals, use the graph to determine the optimal solution for this preemptive goal-programming problem.

Use preemptive goal programming to formulate and solve this problem on a spreadsheet.

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If it is possible to fully satisfy all the goals except the lowest priority goal, one can quickly solve a preemptive goal-programming problem by formulating and solving a linear programming model that includes all the goals except the last one as constraints and then uses the objective function to strive toward the lowest priority goal. Formulate and solve such a linear programming model for this problem on a spreadsheet. What would be the interpretation for the preemptive goal-programming problem if this linear programming model had no feasible solutions?

Perform some what-if analysis by determining how far the total false alarm rate per passenger can be reduced (perhaps even below the goal) by ignoring the second budgetary guideline but fully meeting the first one.

What additional what-if analysis do you feel should be performed in order to provide top management with the information needed to make a sound judgment decision about the best trade-off between (1) the total false alarm rate per passenger, (2) the total expenditure for the two new security systems per security checkpoint, and (3) the total annual maintenance cost for these two systems per security checkpoint?