The company called Office Repair was started as a sideline business to supplement the income from an existing office-supply store.

Office Repair provides equipment repair from 8 AM to 5 PM, Monday through Friday. Customers can select from various types of contracts for service on four different types of equipment: Type 1, Type 2, Type 3, and Type 4. Each contract offers two possible types of service that can be purchased: Premium and Basic.

Premium service: This provides for a three-hour response time, guaranteeing that service will be started within three hours of the time that the service call is received. This three-hour time period does not include any time during which services are not normally provided. For example, if a service call is received at 4 PM on Friday, the company has until 10 AM on Monday to respond. The response time is measured from the time that the call is received until the repairperson arrives, not when the service is completed.

Basic service: This provides a 24-hour response time service is guaranteed to start within the next day, not including the weekend or holidays. Thus, for a call received at 4 PM on Friday, the company has until 4 PM on Monday to respond.

Currently, there are two classes of service personnel available to take service calls: Class A and Class B. Class A service personnel are qualified to service only the Type 1 and Type 2 equipment. Class B service personnel can service all four types of equipment. Current standard costs for service personnel are $200 TL per hour for Class B and $120 TL per hour for Class A.

All requests for service are made to a central dispatching center. If a qualified service person is currently available, the individual is called using cell-phone technology and is assigned the service call. The service person travels to the customer site and performs the service. When the service is complete, the service person calls dispatch and informs them that the job is finished and requests the next service-call assignment.

All service personnel are available from 8 AM until 5 PM. During that time, they are allocated a one-hour lunch break. They never interrupt a service call for lunch, but take their one-hour break between service calls. However, they try to schedule their lunch break between 11:30 AM and 1:30 PM.

Service personnel are never dispatched to a call after 4:30 PM, but are allowed to use that time to complete paperwork. If any basic services are in progress at 5 PM, the service personnel are allowed to work on those calls until they are completed or until 5:30 PM, whichever comes first. No basic service is provided after 5:30 PM. If a service call is interrupted, the service person will return at 8 AM the next workday to complete the service. Premium service calls that are in progress at 5 PM are always completed. All service

time that occurs after 5 PM requires the payment of overtime, a 75% additional cost.

Very few service calls, 1.5%, require a return visit. These calls must be made by the same service person and must be scheduled on the next workday.

Average service calls per hour for each equipment type are included in the following table.

Time Period	Type 1	Type 2	Type 3	Type	4
8 AM - 9 AM	7	8	5	2
9 AM - 10 AM	12	11	6	3
10 AM - 11 AM	10	8	5	4
11 AM-NOON	7	9	4	3
NOON - 1 PM	5	6	3	2
1 PM - 2 PM	4	4	3	1
2 PM - 3 PM	5	3	2	1
3 PM - 4 PM	4	3	2	1
4 PM - 5 PM	3	2	1	1

The percentage of basic and premium contracts is given next.

Service Type	Type 1	Type 2	Type 3	Type 4
Basic Premium	35 65	30 70	25 75	15 85

The travel time, independent of type or service personnel, is estimated to have a mean of about 30 minutes. Typically, it takes at least 10 minutes, and only under extreme conditions does it take more than 45 minutes. About 70% of the time, the traveling is done with a car, which incurs additional cost to the company with an average rate of 20 TL per hour.

A limited amount of service-time data (by equipment type) are included in the data files (named Type1.dst, Type2.dst, Type3.dst, and Type4.dst) for your use.

Performance measures

Customers are satisfied if the time guarantee set forth in their contracts is met. Although it’s not always possible to meet the time guarantees, the company would like to achieve about 85% customer satisfaction rate at the minimum.

The company is looking for a staffing recommendation in order to provide the required customer satisfaction at minimum operating cost. The company also welcomes your recommendations on how to dispatch our service personnel that would improve the overall performance of the operation.

Overall, the performance measures are customer satisfaction rate and operation cost.

Report Format

-Submit a report which includes the details of your work for the following tasks:

a) Structure of the model: State all the entities, attributes, resources, system states, queues, events, activities, and delays of the system.

b) Perform input analysis for the service times using the data in the files provided. You will use the results of your analysis as inputs to your ARENA model.