1. Gary MarsdenSlide 1University of Cape Town Human-Computer Interaction - 10 Mobile Interaction Gary Marsden ( gaz@cs.uct.ac.za ) July 2002

2. Gary MarsdenSlide 2University of Cape Town Next big thing  Mobile computing is about more than making computers smaller (not Pocket PC)  Completely new applications and interactions become possible

3. Gary MarsdenSlide 3University of Cape Town A Little Philosophy

4. Gary MarsdenSlide 4University of Cape Town What are we talking about

5. Gary MarsdenSlide 5University of Cape Town Devices  First thing to note is that these are consumer devices –they must work –they must be useful (not for their own sake) –think watches more than PC  Dancing bears will not cut it –Death of WAP –All cell-phone companies now reporting loss and/or zero growth

6. Gary MarsdenSlide 6University of Cape Town Physical considerations  Mobile devices have smaller screens and keyboards –Computing power is less of an issue  However, –never left behind –can ‘know’ things location heart rate Officially called “context” – research team in UK

7. Gary MarsdenSlide 7University of Cape Town No mouse, no keyboard, no hope?  New innovations –Voice recognition –Invisible keyboard  All very well, but technology based  Can we do any better with the technology we have?

8. Gary MarsdenSlide 8University of Cape Town HCI knowledge  All current cellphone interaction is based on menus  Can you recite your menu structure?

9. Gary MarsdenSlide 9University of Cape Town Actual structure - I Phone Book Search Add Entry Erase Edit Send Entry Options Type of View Memory Status Speed dials Messages Inbox Outbox Write Message Settings Message centre number Message sent as Message validity Common Delivery report Reply via same centre Info Service Off Topics index Topics Select Add Edit Erase Language On Voice mailbox number Call Register Missed Calls Received calls Dialled numbers Erase recent call lists Show call duration Last call All calls Received calls Dialled Clear Timer Show call costs Last call All calls Clear Counter Call cost settings Call cost limit Show costs in

10. Gary MarsdenSlide 10University of Cape Town Actual structure - II Settings Call Settings Auto redial Speed dialling Call waiting option Own number sending Phone Settings Language Cell info display Welcome note Network selection Security settings PIN code request Fixed dialling Closed user group Security level Change access codes Change PIN code Change PIN2 code Change security code Restore factory settings Call Divert Divert all Divert when busy Divert when not answered Divert when phone off Cancel all diverts Games Memory Snake Logic Calculator Clock Alarm Settings Hide Set time Time format Tones Incoming alert Ring tone Volume Message alert Keypad tones Warning and game tones

11. Gary MarsdenSlide 11University of Cape Town Rules of menu design  Classifications typically achieve only 50% success  Alphabetic arrangements support “identity mapping” – expert behaviour

12. Gary MarsdenSlide 12University of Cape Town Current designs  Typical handset – Nokia 5110 – uses classification  Is it good? –Avg: 8.2 –Max: 14 –Total: 110 Number of key presses

13. Gary MarsdenSlide 13University of Cape Town Is this a problem?  Yes!  Orange CSP in UK contacted us because –Couldn’t market vertical services –Spending a fortune on customer support lines  Stories echoed by others such as US-West –big problem with elderly –(surprise success for WAP)

14. Gary MarsdenSlide 14University of Cape Town How to improve  Depth vs breadth –Breadth works better –Actually concave is the best (don’t waste time with branch nodes) –Most handsets follow this  All research conducted on large screen –a single line display is disastrous (3 times slower than a 3 line display) –10 options: Short term memory of 7 +/- 2

15. Gary MarsdenSlide 15University of Cape Town Alternative design  Menus are not optimal for small screens  Could use other data structures  E.g. linear list –Total: 74 –Average: 37  –Max: 74   E.g. Binary tree –Total: 148  –Average: 5.4 –Max: 7

16. Gary MarsdenSlide 16University of Cape Town Lower level - input  It is more likely that mobile devices will be used for data access than intensive data entry –there are exceptions, but these are vertical market (e.g. Psion)  Input solutions include –voice (limited) –handwriting (graffiti) –predictive (T9) –“portable” keyboard

17. Gary MarsdenSlide 17University of Cape Town Output – screen size  There is not much we can do about keyboard size – Fitt’s law and ergonomics dictate  How does screen size affect usability?

18. Gary MarsdenSlide 18University of Cape Town Is height important  Yes, but width is more so  Full width screen (640) read 25% more quickly than 210 –not happy with horizontal scroll  Optimal height is 4 lines – increasing to 20 only gives 9% speed increase in reading

19. Gary MarsdenSlide 19University of Cape Town Comprehension rates  Study conducted by Dillon using a 3500 word text on 20 line displays and 60 line displays –no difference in comprehension (summary of main points) –small screen users, however, perceived that they were worse off  This was for linear text  Things more interesting with hyper-text

20. Gary MarsdenSlide 20University of Cape Town Web studies  Previous work carried out on terminals in the 80’s which had small screens –Seems to say the short, wide screens should work  We were set problem by Reuters for accessing Web information  Conducted experiment on real Web site –used standard PC’s, one dropped to 640x480 15x75 compared to 11x65 on Psion and WinCE –set tasks to find information

21. Gary MarsdenSlide 21University of Cape Town Screen shots

22. Gary MarsdenSlide 22University of Cape Town Experiment results  Small screen (640x480) experiment showed –ss users twice as likely to make mistakes in comprehension –both groups followed same amount of links –80% of ss users started by using the search feature: twice as likely to search as ls users –ls users had longer path lengths – more exploratory –ss users did a lot more scrolling, but only down and to the right  Design lessons –??

23. Gary MarsdenSlide 23University of Cape Town New interfaces to m-applications  Given those design criteria, what should mobile web applications look like?  WebTwig –35% quicker –Greater satisfaction

24. Gary MarsdenSlide 24University of Cape Town Technologies  WebTwig is only one approach  Technologies change all the time  E.g. could use handheld to find pages for off-line reading –then use BlueTooth to beam them to TV or printer  Do not be technology focused, however –Learn from WAP!

25. Gary MarsdenSlide 25University of Cape Town Summary  Don’t get locked in to new technology for its own sake  Use evaluation –Expert –User models –Actual humans