exercises

21. hypertext, multimedia and the world-wide web

EXERCISE 21.1

Experiment with HyperCard or another hypertext system if you have access to one. As you work through the system, draw a map of the links and connections. Is it clear where you are and where you can get to at any point? If not, how could this be improved?

answer

This is an experimental exercise which requires access to a hypertext system. It can be used as the basis for a practical class, in which students analyze the effectiveness of the system.

Drawing the map has two purposes: one is to reinforce the overall structure of the hypertext; the other is to test the navigational support that is available. Whether it is sufficient will depend on the system under scrutiny, but possible improvements would be to provide an explicit map, escape buttons, explicit paths to core material. The system may of course incorporate such features.

 

EXERCISE 21.2

Do the same for this book's website and tell us what you think!

answer

open-ended investigation

 

EXERCISE 21.3

What factors are likely to delay the widespread use of video in interfaces? What applications could benefit most from its use?

answer

Some of the factors are the costs in terms of hardware and software for compression and decompression; the slow speed due to the high bandwidth; the overall cost of equipment (for example, camera, video, CD); the lack of design tools to exploit video; the lack of specialist skills amongst designers. Many applications have been suggested as candidates for the integration of video. Educational systems, games and help systems are liable to benefit since information can be passed more clearly and memorably and new dimensions added. Other areas such as virtual reality can use video together with graphics in the creation of their artificial worlds. CSCW systems can use video to provide a face-to-face communication link between distributed workers (see Chapters 14 and 19). However, although these appear to be areas where video has a promising future, its use needs to be carefully considered and its consequences investigated. It may be that it will not fulfil its initial promise.

 

EXERCISE 21.4

Using a graphics package such as Adobe Photoshop or Macromedia Fireworks, save different types of image (photographs, line drawings, text) in different formats (GIF, JPEG, PNG). Compare the file sizes of the different formats, experimenting with different compression ratios (where applicable), numbers of colours, etc.

answer

open-ended investigation

 

EXERCISE 21.5 [extra - not in book]

What are the benefits and limitations of the world wide web as a platform for the provision of groupware?

answer available for tutors only

Benefits: accessibility and availability, cross-platform, increasing familiarity, supports all necessary media.

Limitations: relatively low bandwidth, difficult to make assumptions about participants' resources, limited to standard-sized screens, difficult to support synchronous groupware

See chapter 21 links on the textbook web site, www.hcibook.com/e3/chaps/ch21/links/, for pointers to examples of WWW CSCW systems.

 

EXERCISE 21.6 [extra - not in book]

Chapter 2 of Human-Computer Interaction explores a number of traditional input and output devices. The pace of technological change means that such an exploration will always be incomplete. This exercise asks you to conduct a search on the Web to uncover information about novel (at least novel to you) input and output devices.

For each device (one input, one output) produce a short description of its function, web references for more information and, if possible, information on vendors for the product.

answer available for tutors only

open-ended research exercise

 

EXERCISE 21.7 [extra - not in book]

You have been asked to design a world wide web search engine for children. What technology and interaction style would be appropriate for the system?

If you want to extend this question into a small research exercise, visit the site Ask Jeeves Kids www.ajkids.com, and analyze its interface in terms of the interaction style you described. What is the purpose of the elements that make up the design? How might it differ if aimed at older people? If you can enlist the help of a child, evaluate the design of this or a similar site using an appropriate evaluation technique. What are the strengths of the interface? Do you detect any usability problems? If you do, what improvements could be made?

For links to resources on designing for children, see Gary Perlman's Kids and Computers page: www.hcibib.org/kids/

answer available for tutors only

Little choice of physical hardware as users have their own computers: keyboard, mouse, standard PC configuration.

Choices are in how to use it: interface style simple - possibly allowing selections from suggested lists, etc., minimise need to type in and especially remember words, large image icons for young children who may have trouble controlling the mouse. Lots of feedback and colour - even ... animated images! Remember also that some metaphors and icons that are perfectly recognisable for adults may not be so for children.

The second part of this exercise is open-ended.

 

EXERCISE 21.8 [extra - not in book]

Look up and study the Yale Style Manual info.med.yale.edu/caim/manual/contents.html, which draws on HCI research. Identify the usability principles upon which the web guidelines are based. If you have a web page or site, take time to analyze how it accords with (or violates) the guidelines. (You may not agree with all of them, but you should be able to offer a principled argument for any points of disagreement.) If you don't have your own web site, start looking from an HCI perspective at the sites you visit, using the guidelines to help you. Note examples of usable sites, and try drawing up your own 'top ten' guidelines for novice web designers.

answer available for tutors only

open-ended investigation

 

EXERCISE 21.9 [extra - not in book]

The web is constantly changing and evolving, at a speed that dates printed media even before it reaches the bookshops. In such an environment, the web is an invaluable resource to supplement books like Human-Computer Interaction.

Research the technologies that enable dynamic interfaces on the web. There are some starting points in the links for this cahpter textbook's web site www.hcibook.com/e3/chaps/ch21/links/. How might these technologies benefit users? Think about educational applications, working practices, business, leisure, etc.

answer available for tutors only

open-ended research exercise

 

EXERCISE 21.10 [extra - not in book]

The design of a multimedia system involves mapping the structure of information, and determining the links and potential pathways. Choose a subject you are interested in and know something about, and design a prototype multimedia system, (for now, focus on only a limited area of the subject). Jot down anything you can think of about the subject: facts, ideas, sources of information, people, places - the kinds of things you note down will depend on your particular subject.

Use your knowledge of task analysis, semantic networks and other knowledge representation models to help you visualize the structure of the information and the relationships between different aspects of it. Use diagrams, lists, or whatever you think appropriate to organize the material.

Decide what information to include (and what you should leave out). An understanding of the user's purposes and tasks when using the proposed system will be essential here.

You then need to apply this semantic knowledge to the detailed design. Where will your hotspots be? How will users navigate without getting 'lost in hyperspace'? Can you take advantage of the medium to ease information retrieval? (For example, unfamiliar words in a text can be linked directly to their definitions in a glossary - don't forget to provide a way of getting back to the text as well!). Does the subject matter lend itself to animation, so that the user can see things 'happening'?

As you explore the medium, new possibilities will suggest themselves; as with other systems, look at, and learn from, examples of good (and bad) practice (libraries often lend multimedia as well as books).

Consider appropriate evaluation techniques for your prototype, at what stage to use them (paper design, simulated screens, full working prototype) and whether you need to evaluate the system as a whole or focus on specific 'difficult' areas.

You can end the exercise at the design stage, or go on to implement your hypertext, as a web site, or, if you have the resources, as a multimedia application on CD.

answer available for tutors only

extended project

 

EXERCISE 21.11 [extra - not in book]

A web site designer has been asked to design a web-based hotel finder for Lancaster Tourist Board. Hotels are added to a database using an existing non-web interface, usually in batches at the end of the week. You do not need to consider this interface, but should consider the rate of update in your answer.

The first stage of the project will offer the users various fixed views of the hotels, by area, by price range etc. The user will choose a particular area or price band and will then see a screen as shown below.

The display has three areas (a) a heading (b) a list of hotels and (c) the details of one of the hotels. As the user selects different hotels in (b) the details in (c) are updated to reflect the chosen hotel.

Stage two will allow the user to specify queries based on criteria like price, facilities etc. and obtain similar custom search result screens.

Discuss the different architectural choices suitable for implementing this over the web. Distinguish those options that would be suitable for the first stage only and those that would be suitable for both. Include discussion of client/server side processing options for interactive elements.

answer available for tutors only

Some students may talk in terms of particular technologies (CGI etc.), others in more general terms (server-side processing). I'm interested in the overall architecture client/server trade-off, so either approach is acceptable.

  • They ought to take into account the slow rate of update here. For fixed view, periodically generating pages offline from a database would be a sensible approach and then using standard web server.
  • The hotel details could managed by web transaction as each hotel is clicked, or could use client side (Java or JavaScript) - I'm looking for mention of different rate of feedback for the user.
  • In stage 2 more dynamic database access is required, not because of the rate of update, which is still the same, but because of the more complex queries.
  • Students may use pictures like figure 21.14 and the better students may draw parallels with the Seeheim model.

 

EXERCISE 21.12 [extra - not in book]

List and briefly discuss two HCI challenges of Web2.0 and recent web technologies.

answer available for tutors only

May include issues of trust, privacy, increasing importance of experience, javascript meaning less standardised widgets.

Individual exercises

ex.21.1 (ans), ex.21.2 (ans), ex.21.3 (ans), ex.21.4 (ans), ex.21.5 (tut), ex.21.6 (open), ex.21.7 (tut), ex.21.8 (open), ex.21.9 (open), ex.21.10 (open), ex.21.11 (tut), ex.21.12 (tut)