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Human Computer Interaction 3rd Homework

1. Distinguish between 'principles', 'design rules', and 'standards'

Design principles are a generally and widely applicable guideline and low in authority. However, Design rules tend to give precise recommendations about specific design aspects.

The method to distinguish between principles and rules depends on how many ways it is interpreted. For example, 'Use captions to clarify and give support to the image.'¹⁾. It can only be interpreted one way, therefore it's design rule. However, 'Be balanced.'²⁾. It can be interpreted many ways, such as making 'symmetrical balance' or 'asymmetrical balance'. So it's design principle.

Standards tend to be imposed by a particular organization such as ISO³⁾, IEEE⁴⁾. Quite often, they are mandatory and may legally enforced. For example, WIPI⁵⁾ is a mobile platform standard. If mobile company want to sell the phone in Korea, they must load the WIPI in their product.

2. Explain Simplex One model

To understand UCSD, We first need to understand the people who will use our systems. One way to do is the user modelling. There are many kinds of user modelling concepts, Broadbent's Maltese Cross, Barnard's Interacting Cognitive Subsystems, Anderson's ACT series of models, SOAR and Simplex One.

Those things are not good that it's hard to learn, everytime Designer make a new theory of the users or it's past its sell-by date. However, Simplex One is not. It provide a powerful framework for complex theories and an overall depiction for designers without requiring full theories.

Simplex One's objective is to understand better the key design issues in regard of the psychology of users. It has five modules of cognition, Perception(Input), Response(output), Abstract working memory(short-term memory), Long-term memory and Execution functions. These are each partially independent and acting as von Neumann machine. It provides a simple, yet elegant, framework for interactive system designers.

Simplex One

● Perception (input)

It is ability to take in new information from the senses, to analyse and store that information and to relate currently held information to it.

● Response (output)

It is ability to select, organize, time and implement appropriate responses.

● Abstract working memory (short-term memory)

It is to take, hold and process task-relevant memories while they are needed to support action. It's a limited capacity, time-limited system.

● Long-term memory

It is a storehouse to save the co-occurrence of key events and symbols.

It has two categories, episodic memory and semantic memory.

Episodic memory is events that person have experienced and memory about the anecdote. For example, "Last Tuesday, I've been to Ubicomp conference with my schoolmate. I heard some topics security, design and ubiquitous." There are 4(or 5) discrete facts in this memory.

Semantic memory is conceptual knowledge memories. It's about various kinds of vocabularies, linguistic concepts and general worldly affairs. For instance, "Ubicomp is a shortened word Ubiquitous computing.".⁷⁾

Above the picture, there is a table that man works and a shelf that man arrange the tools and stuffs. The table is like a short-term memory and the shelf is a long-term memory. The table has limited area, but easy to work there. The shelf has a lot of area to save things, but if you work with tools in the shelf, then you should draw out it to the table.

● Execution functions

Each module can take input from any other module via executive function.

3. Explain Nielsen's heuristics

All principles can be used as heuristics. The search is a search for potential usabillity problems with a design. And they are normally used as a checklist for a design. There are several sets of heuristics. 'Norman's seven principles', 'Schneiderman's eight golden rules', 'Tognazzini's interaction design principles' and 'Nielsen's heruistics'.

In Nielsen's heruistics, there are ten rules.⁹⁾

● Visibility of system status

The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

For example, Download status window.

10)

If users download the file on the internet, browser create the download window. In this window, downloading file name, remained time, total file size, downloaded file size, current download speed and progress bar. Therefore users easily know that how many time does it wait, Is the internet speed is good or bad, etc.

● Match between system and the real world

The system should speak the user's language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.

For instance, the sandglass in Windows animation mouse pointer.

In real world, sandglass is counting time or waiting time to do other things. For example, people count the time where they in a sauna bath. And in Windows, when users order the operation such as click the icon or button, mouse pointer is changed to sandglass. Then users easily know that they should wait.

● User control and freedom

Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue.

For example, there are default button.

If users mistake to change the mouse operation, they have problems and what is wrong. That time click the default restoration button is helpful. If users click that button, all the things are changed to status when users use the system at the first time. I think it is same concept with Undo.

● Consistency and standards

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

For example, there is many homepage's main page logo in top left side.

I search the word HCI in NAVER¹¹⁾, Google¹²⁾, Daum¹³⁾, empas¹⁴⁾, YAHOO¹⁵⁾, and altavista¹⁶⁾. And If I want to back to these main page, I click the logo in top-left side. Almost (maybe overall) homepage have their logo that is linked their main page in same place. Therefore although users visit the new homepage, users easily know that how to go to its main page.

● Error prevention

Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

● Recognition rather than recall

Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.

● Flexibility and efficiency of use

Accelerators -- unseen by the novice user -- may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.

For example, searching using Google.

17)

18)

In Google search, there is one input box in search page. But if users want to more exact result, they can use advanced search page. There is many input box and options.

● Aesthetic and minimalist design

Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility.

For example, NAVER SE serach.

19)

20)

If users want to search the internet using NAVER, they go to naver main page. However, there are so many things including AD banner, login box, news, etc that users don't want to see and rarely needed. Therefore, NAVER set the page for using web search. It's very simple like Google main page and users can search the internet.

● Help users recognize, diagnose, and recover from errors

Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.

For example, error message window.

21)

²²⁾

When computer have problem or error, there is error message in blue screen. There is little useful information in Windows 95, 98 and ME's blue screen. But in Windows XP blue screen became more information. Therefore, If users see the error message, they search the error code such as "0x000000BE" on the internet and can fix the problem.

● Help and documentation

Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.

Reference

Serengul Smith-Atakan, <Human-Computer Interaction>, THOMSON, 2006, pp.28~45

김희철, <인간과 컴퓨터의 상호작용:인컴학을 향하여>, SciTech, 2006, pp.296~302

Professor Chang Wook Ahn, 5th_Lecture(Sep_19).pdf

한덕웅 외 15인, <인간의 마음과 행동>, 박영사, 2004

http://www.writedesignonline.com/resources/design/rules/layout.html

http://www.digital-web.com/articles/principles_of_design

http://ko.wikipedia.org/wiki/WIPI

http://www.useit.com/papers/heuristic/

http://en.wikipedia.org/wiki/Heuristic_evaluation

1) http://www.writedesignonline.com/resources/design/rules/layout.html

2) http://www.digital-web.com/articles/principles_of_design