CS 160: User Interfaces Fall, 2006 Midterm Exam Maneesh Agrawala October 16, 2006 Your name (please print): ______________________________________ This is a closed book, individual test. You are not allowed to use your notes, texts, or any electronic devices including laptop computers, calculators or cell phones. You have 75 minutes for this exam. There are a total of 125 points. Use your time accordingly. Before you begin, write your name on every page! You will lose 1 point if you do not do this. If you find a question ambiguous, document the ambiguity. Indicate the way you interpreted the question in a set of separate sentences next to the question. The questions on the exam are not intended to be ambiguous, but sometimes another meaning is interpreted by the examinee that we did not take into consideration.Page 2 of 10 Your Name:____________________ Q1: Short Answers (35 pts) We have seen several versions of the design cycle in this class. But they all have three main stages in common. Name the 3 main stages of the design cycle. (3 pts) According to Norman, in the context of interface design, what is a mapping? (2 pts) Give an example of interface for which the mapping is clear and one for which the mapping is unclear. (4 pts) In Norman’s action cycle he describes the gulfs of execution and evaluation. Briefly explain what the gulfs of execution and evaluation are and how they differ from one another (6 pts). (Hint: It may help to draw a figure of the action cycle)Page 3 of 10 Your Name:____________________ What is a mode? (2 pts) What is 1 problem that modes cause? (1 pt) What is a quasimode? Why is a quasimode more effective than a regular mode? (4 pts) Give an example of a quasimode. (1 pt) Describe 2 advantages of using a low-fidelity sketched storyboard over carefully designed high-fidelity images in the early stages of interface design. (4 pts) What is Fitts’ Law (Full credit for giving any valid mathematical expression of the law and an explanation of what it means. Partial credit for explanation only.)? (4 pts)Page 4 of 10 Your Name:____________________ What is the index of difficulty for a target that is 0.5 cm wide and 3 cm away from the pointer position? Describe two ways to decrease the index of difficulty for this task. (4 pts)Page 5 of 10 Your Name:____________________ Q2: Comparison of 3 Technologies (30 pts) Standard pens-and-paper, the Anoto digital pen system and Tablet PCs are three competing technologies that offer different advantages and disadvantages. Briefly describe 3 applications. 1) one that would work well with standard pens-and-paper, but not very well with the Anoto system or a Tablet PC, 2) one that would work best with the Anoto system, but not very well with standard pens-and-paper or a Tablet PC and 3) one that would work best with a Tablet PC, but not very will with standard pens-and-paper or the Anoto system. Explain why each application is well suited to one technology but not the other two.Page 6 of 10 Your Name:____________________ Q3: The Human Information Processor (30 pts) Label the 5 major parts of the human processor model as well as any associated sub-parts. (5 pts)Page 7 of 10 Your Name:____________________ Briefly explain what each of the 5 main parts of the human model processor does. (10 pts) The cycle time of perceptual processor is about 100 ms. What does this cycle time imply about perception of events that are closely spaced in time? What does this cycle time imply about feedback (5 pts) Explain what is the model useful for in HCI? (5 pts) Describe problems, failures or other aspects that may be missing from the model. (5 pts)Page 8 of 10 Your Name:____________________ Q4: KLM Analysis (30 pts) K: pressing a key or pressing and releasing a button = 0.2s P: pointing = 1.1s (without button press) H: Homing (switching device) = 0.4s M: Mentally prepare = 1.35s Rules 0: Insert M in front of all K’s and in front of all P’s selecting a command (not in front of P’s ending a command). 1: Remove M between fully anticipated operators 2: if a string of MKs belong to cognitive unit delete all M but first 3: if K is a redundant terminator then delete M in front of it 4a: if K terminates a constant string (command name) delete the M in front of it 4b: if K terminates a variable string (parameter) keep the M in front of it You are designing a web-based form for entering addresses and are considering two possible designs. In the first design the user types the two letter state code as shown in the figure below. Use the Keystroke Level Model to determine how long a user would take to enter the state code for California (CA). Assume that the user just finished typing the city name in a separate textbox and must use the mouse to move from textbox to textbox in the form. Figure 1: Entering two letter state code via typing. In your answer be sure to explain what action each KLM symbol (K, P, H, M) corresponds to. We will give partial credit for showing intermediate steps in your derivation of task completion time. (15 pts)Page 9 of 10 Your Name:____________________ In the second design the user chooses the state code from a drop-down menu with state codes arranged in alphabetical order. Again use KLM to determine how long a user would take to enter the state code for California (CA is the 5th state in alphabetical order). Assume that the user has just finished typing the city name in a separate textbox and must use the mouse to move from textbox to the drop-down menu. Also assume that once the drop-down list is has been expanded the user users the down arrow key to move down one entry at a time through the list. Figure 2: Entering 2 letter state code via drop-down menu. Before expanding the drop-down menu. Figure 3: Entering 2 letter state code via drop-down menu. Immediately after expanding the drop-down menu. In your answer be sure to explain what action each KLM symbol (K, P, H, M) corresponds to. We will give partial credit for showing intermediate steps in your derivation of task completion time. (15 pts) There is an extra credit question on the next page!Page 10 of 10 Your Name:____________________ Bonus Question (5 Extra Credit pts): Assuming all 50 states were equally likely to be chosen, how long would it take on average to use the second design to enter the state
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