1. Types of users
1. Anyone
1. Anyone may use the search features of the system.
2. Anyone may look at an auction's information.
2. Members
1. Only members may bid or place items for sale.
2. All members must register with the system.
3. Members must supply their name and a valid e-mail address.
4. After registering, the system will create an account for the member.
1. A password will be mailed to the e-mail address specified.
5. Members must log in to bid or place an item for sale.
6. Members who forget their password can have it re-mailed to them.
2. Auctions
1. An auction involves an item, a seller, and zero or more bidders.
2. Items and sellers
1. Sellers put up items for auction
2. The item must include a name, a closing time, and a minimum bid.
3. The item may include a description and a picture.
4. Sellers may have any number of auctions active at one time.
3. Bids and bidders
1. Any member may bid in any auction.
2. Bids may be placed at any time before the closing time.
3. A bid must be at least the minimum bid, and higher than any bid so far.
4. Ending an auction.
1. No matter how an auction ends, it is immediately removed from the list of active auctions.
2. If no bids are placed before the closing time, the auction is closed unsuccessfully and the seller notified by e-mail.
3. If at least one legal bid has been placed before the closing time, the auction is closed successfully. The winning bidder and the seller are both mailed each other's contact information and the winning bid.
4. The seller may cancel the auction up to 24 hours before the closing time. All bidders on this auction will be mailed a notice of the cancellation.
3. Searching
1. Any user may search through active auctions by keyword.
2. All active auctions with name or description containing the keyword are presented to the user.
1. The auctions are sorted by closing time in chronological order.
2. The user may click a link to go directly to the auction.

Create a use case diagram for this system.

1. Carefully interpret/explain this model.

   

2. How can this model be improved?

3. Build a new model that allows for people to be members of an organization. (Note: The organization should have one address and everybody associated with that organization should have that address. The organization may have a central phone number and email address and everybody associated with the organization may have one as well.)

1. There is a major problem with this state diagram. What is it?

2. How would you fix this problem? (You may modify the above diagram or draw a new one.)

Implement the Drawing class in either Eiffel, C#, C++, Java, or Smalltalk. (Note: You may work at a computer when answering this question. That is, you may edit, compile, and execute your code before you "submit" it.)

1. Identify two hazards that may arise in this system.

2. For each hazard, suggest a defensive requirement that will reduce its probability.

    public static int calculate(int x, int y)
    {
       int        a, b;

       do
       {
          a = 1;
       
          if (x > y)
          {
             a = 2;
          }

          x++;     
          b = x * a;
       }
       while (b <= 0);
       
       return b;         
    }
    

Develop a set of test cases that will test every path through this method.

    // Details omitted

     a = in.nextInt();
     b = in.nextInt();
     c = a/b;
    

where the nextInt() method will return the next integer value in the input stream associated with in.

1. Identify one fault in this fragment.

2. Identify one failure that would be caused by this fault.

3. A symptom is a characteristic of a failure that helps you recognize that a failure has occurred. Identify a symptom for this failure.

4. Give one condition that will cause a fault in this fragment to result in a failure.

    Year          Cost
      1         3,000,000
      2         2,700,000
      3         1,200,000
      4         5,100,000
      5         8,000,000
    

    Year          Cost
      1         1,500,000
      2         1,500,000
      3         1,000,000
      4         2,400,000
      5           500,000
      6         1,500,000
      7         1,500,000
      8         2,100,000
      9         6,000,000
     10         2,000,000
    

Calculate the present value of each of these two cost streams assuming a discount rate (i.e., interest rate) of 7 percent and that all costs are incurred at the end of the year.

               Time
    Task     Required      Dependencies
      1          6              
      2          5              1
      3          2              1
      4          6              1
      5          4              2,3
      6          1              4
      7          2              4
      8          4              4
      9          3              2
     10          4              5,6
     11          1              7,8
     12          4              9,10
     13          2              6,11
     14          1              12,13
    

1. Construct an activity network.

2. Identify the critical path.

3. Explain why delays in activities that do not lie on the critical path do not necessarily cause slippage in the overall schedule. Provide an example.