Friday, December 13, 2013

Quality of Services (Human Computer Interaction)

With the huge development of World Wide Web there are one problem affected by graphics and network congestion effect which is response time. Time is so precious now for user because a lengthy or unexpected system response time can produce; Frustation, Annoyance and Eventual Anger.

In contrary if system is too fast then it can result in user less learning, reading with lower comprehension, making more ill-considered decisions and commiting more data-entry errors.

Models of Response-Time Impacts

Response time
The number of seconds it takes from the moment users initiate an activity until the computer presents results on the display

User think time
The number of seconds the user thinks before entering the next action

Introduction

Goals of Collaboration and Participation

People Collaborate because doing so is satisfying or productive. Collaboration can have purely emotionally rewarding purposes or specific task-related goals.

Understanding the processes and strategies of the participants facilitates analysis of these varied situations for collaborative interfaces :

Keyboard Layouts

QWERTY layout (1870 Christopher Latham Sholes)

Good mechanical design and a clever placement of the letters that slowed down the users enough that key jamming was infrequent.
Put frequently used letter pairs far apart, thereby increasing finger travel distances

Dvorak layout (1920)

Reduces finger travel distances by at least one order of magnitude
Acceptance has been slow despite the dedicated efforts of some devotees
It takes about 1 week of regular typing to make the switch, but most users have been unwilling to invest the effort

ABCDE style

26 letters of the alphabet laid out in alphabetical order nontypists will find it easier to locate the keys

Additional keyboard issues

IBM PC keyboard was widely criticized because of the placement of a few keys

backslash key where most typists expect SHIFT key
placement of several special characters near the ENTER key
Number pad layout
wrist and hand placement

Introduction

Menu is a way to present available instructions for users. Form fill-in is a mean for interactive system to ask data or information from users. Dialog box is a response from interactive system after users give intructions that need parameters, e.g. When users click Open icon

The primary goal for menu, form fill-in, and dialog-box designers is to create a sensible, comprehensible, memorable, and convenient organization relevant to the user's task

There are several type of menus :

Single menus
linear sequence menus
tree structure menus
cyclic and acyclic network menus

Introduction

The enthusiastic users report the following positive feelings:

Mastery of the interface
Competence in performing tasks
Ease in learning the system originally and in assimilating advanced features
Confidence in the capacity to retain mastery over time
Enjoyment in using the interface
Eagerness to show off the interface to novices
Desire to explore more powerful aspects

Pendahuluan

Seorang desainer yang terlibat dalam pembuatan suatu produk bisa saja membuat kesalahan tanpa menyadarinya. Sebelum digunakan produk harus diuji secara luas untuk menemukan error-error yang ada namun uji secara luas memakan biaya yang lumayan mahal oleh karena itu rencana evaluasi dibutuhkan.

Beberapa faktor yang menentukan rencana evaluasi (evaluation plan) :

Stage of design
Novelty of project
Number of expected users
Criticality of the interface (life-critical medical system vs museum exhibit support)
Costs of product & budget allocated for testing
Time available
Experience of the design and evaluation team

Managing Design Processes (Human Computer Interaction)

Organizational Design and Support Usability

Design is a creative activity whose aim is to establish the multi-faceted qualities of objects , processes, services and their system in whole life cycles. (ICSID - International Council of Societies of Industrial Design)

(Rosson and Carrol, 2002) method to characterize design is :

Design is a process
The design porcess is nonhierarchial.
The process is radically transformational
Design intrinsically involves the discovery of new goals.

Four Pillars of Design

User-interface Requirements
Guidelines Documents & process
User-Interface Software Tools
Expert Reviews & Usability Testing