1. In the Model Human, what are the three processors that are involved in GUI tasks?
2. Fitt's law can be stated as follows: \[ T = a + b \cdot \log(D/S + 0.5) \]

   where \(T\) is the time to acquire a target, \(D\) is the distance to the target, and \(S\) is the size of the target. Explain the significance of Fitts's law.

1. Identify all of the activities in this diagram.
2. Identify all of the object/data nodes in this diagram.
3. Identify all of the actions in this diagram.
4. Identify all of the decision nodes in this diagram.
5. Identify all of the fork nodes in this diagram.
6. Identify all of the join nodes in this diagram.
7. Identify a control flow in this diagram.
8. Identify a data flow in this diagram.
9. Can "Pick Order" and "Create Invoice" occur at the same time?
10. Can "Record Order" and "Ship" occur at the same time?

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.

Use Case: 
     PayForProductWithCard

Actors: 
     User, Bank, Cashier

Trigger: 
     User inserts Card

Precondition:
     The Cashier has taken the product from the User
     and entered the price of the product into the System.

Basic Flow:

     1.  The System reads information off of the Card

     2.  The System prompts the User to enter the type of Card
         (presenting the options "Credit" and "Debit" and "Cancel").

     3.  The System displays the amount of the payment 
         (in dollars and cents).

     4.  The System prompts the User to approve the payment (presenting
         the options "Yes" and "No").

     5.  If the User approves the payment a transaction is sent to the
         Bank and the Cashier is notified to give the product to the User.

Extensions:

     5a. If the User does not approve the payment, the Cashier
         is notified to keep the product and the System is reset.

Identify all of the problems in this use case description and write an improved version.

/**
 * The requirements of a Playable in a song
 */
public interface Playable
{
    /**
     * Play this Playable
     */
    public abstract void play();
}
  

/**
 * A single Note in a song
 */
public class Note implements Playable
{
    // Details omitted


    /**
     * Explicit Value Constructor
     *
     * @param pitch    The pitch ('A','B','C','D','E','F', 'G' or 'R')
     * @param sharp    true for a sharp and false for a natural
     * @param octave   The octave (relative to middle C)
     * @param duration 1 for whole notes, 2 for half notes, etc...
     * @param dotted   Whether the note is dotted
     */
    public Note(char pitch,   boolean sharp, int octave, 
                int duration, boolean dotted)
    {
       // Details Omitted
       
    }


    /**
     * Play this Note
     */
    public void play()
    {
       // Details omitted
    }
}
  

/**
 * A Chord in a song
 */
public class Chord implements Playable
{
    // Details omitted


    /**
     * Explicit Value Constructor
     *
     * @param notes   The Note objects in the Chord
     */
    public Chord(List<Note> notes)
    {
       // Details Omitted
       
    }


    /**
     * Play this Note
     */
    public void play()
    {
       // Details omitted
    }
    
}
  

create a Lyric class that specializes the Note and adds a void setSyllable(String s) method and a String getSyllable() method. Remember to include an appropriate constructor.

1. What kind of UML diagram would you use to describe the static structure of such a system?
2. What kind of UML diagram would you use to describe the dynamic behavior of such a system?
3. How should you verify such a system? (Note: You must discuss both unit testing and system testing. You may also need to discuss other aspects of verification.)