HUMAN-COMPUTER INTERACTION (HCI) & WEB DESIGN Revision- 1.0 ]
Iqbal Chowdhury 22 Bloomdale Street. Laguna Belair 2 , Santa Rosa City, Laguna Email : Iqbal.Chowdhury.firstname.lastname@example.org , Handphone: (0917) 554 6549
Contents. Fundamentals. The Human. The Computer. Interactions. Interaction design. Design rules. Implementation support. Evaluation technique. Universal design 10.User support systems
What is HCI? ■ Human-Computer Interaction (HCI) is afield of study on the design of computer technology and, in particular, the interaction between humans (the users) and computers. It encompasses multiple disciplines, such as computer science, cognitive science, and human-factors engineering.
Definition On a Human-Computer Interaction (HCI) , human is the user but not necessarily mean an individual, it can be a single, a group of users or a sequence of group of users By computer, it mean any technology ranging from desktop or portable to large scale computer, a process control system or an embedded system By interaction, it mean any communication between a user and computer, be it director indirect.
Why we need to understand human Interacting with technology is cognitive Human cognition process is involved when interacting with system, like attention, perception, recognition, memory, learning , reasoning, problem solving and decision making Human capabilities are limited Provide knowledge about what user can and cannot be expected to do Identifies and explain the root cause of the problems users encounter Supply theories, modelling , guidance and methods for improved interactive systems.
Input-output channels A person’s interaction with the outside world occurs through information being received and sent input and output. ■ In an interaction with computer, a user receives information from the output of computer, user’s output becomes computer’s input and vice versa Input inhuman occurs through senses (sight, hearing, touch, taste and smell) and output through control of the effectors (limb, eyes, fingers, head and vocal system).
Role and limitation of primary senses Vision – Human vision is a highly complex activity with a range of physical and perceptual limitations. It is primary source of the information Visual perception – a) perception of size and depth b) perceiving brightness (measured in luminance) c) perceiving color.
Limitations of visual processing Visual processing involves the transformation and interpretation of a complete image, from the light that is thrown onto the retina. If you look at the dot, which side of the alphabets are more easy to read Is this a ambiguous shape?
Design focus Optical illusions highlight the differences between the way things are and the way we perceive them and in interface design we need to be aware that we will not always perceive things exactly as they are. The way that objects are composed together will affect the way we perceive them, and we do not perceive geometric shapes exactly as they are drawn. Optical illusions also affect page symmetry. We tend to seethe center of a page as being a little above the actual center – so if a page is arranged symmetrically around the actual center, we will see it as too lowdown. In graphic design this is known as optical center. Reading a) Adult read approximately 250 words a minute. b) Words can be recognized as quickly as single characters. c) Familiar words are recognized using shaped) Fonts size 9 – 12 are easiest to read. e) Line length between 2.3-5.2 inches are equally legible. f) A negative contrast (dark characters in light screen) provides higher luminance.
Input-output channels Hearing- Secondary to sight. It provides enormous amount of information. Such as source and direction of sound. It is the vibration in the air of sound waves. Ear a) Human ear can hear frequencies from Hz to 15kHz. b) It can distinguish frequency changes of 1.5Hz. c) Different frequencies trigger activity in neurons indifferent parts of the auditory system. d) The auditory system performs some filtering of the sounds received, allowing us to ignore background noise and concentrate on important information. e) Sound could be used more extensively in interface design, to convey information about the system state. Touch - Although this sense is often viewed as less important than sight or hearing, imagine life without it. Touch provides us with vital information about our environment. It tells us when we touch something hot or cold, and can therefore act as a warning. It also provides us with feedback when we attempt to lift an object.
Input-output channels Human memory Sensory memories (Iconic) (Echoic) (Haptic) Short term memory or Working memory Long term memory Attention Rehearsal