Reading assignment: Chapters 13, 10

Homework must be neat and readable.  At the top of every page you must include your name, the assignment number, and the due date.  Clearly indicate the question you are answering. You do not need to copy the entire question, but you must mark the question number and a brief description at the beginning of your answer for each question.

1. What interfaces does QuikPay have with external systems? Use the QuikPay External Systems diagram to help you answer this question. For each external interface, describe what must be transmitted across the interface. Name one or more standards could apply to each interface.
2. After working with stakeholders, systems engineeers for QuikPay have established that the reasonable worst availability, measured as percent of attempted transactions completed successfully, is 98%; the reasonable best is 99.9%; and the single-attribute utility function for availability is linear.  Two design options are being considered. Option #1 has estimated availability 98.5% and Option #2 has estimated availabiltiy 99.0%. Find the single-attribute utility for availability for Option #1. For Option #2.
3. The reasonable worst transaction error rate is 1 error per 1,000 transactions; the reasonable best is 1 error per 10,000 transactions.  Assume that the single-attribute utility funtion for transaction errors is a linear function of the logarithm of the error rate.  That is, the utility is a linear function of the logerr score, where logerr is defined as as the negative logarithm of the number of errors divided by the number of transactions. (For 1 error in 1,000 transactions, the logerror is 3, and for 1 error per 10,000 transactions, the logerror is 4.)  Option #1 has an estimated 1 error in 6,000 transactions, and Option #2 has an estimated 1 error in 3,200 transactions, respectively.  What is the single-attribute utility  for transaction errors for Option #1? For Option #2?
4. After interviewing stakeholders and the customer, it has been agreed that moving from 98% to 99.9% availability is about equal in value to moving from 1 error in 1,000 transactions to 2 errors in 3,500 transactions.  From this information, compute multiattribute utilities for Option #1 and Option #2. Which option is preferred according to this value model?

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