SE234: Human Computer Interaction Chapter 2-4

The Computer

• A computer system consists of various elements that affect interaction, including input devices, output devices, virtual reality, physical interaction, paper, memory, and processing.

Interacting with Computers

• To understand human-computer interaction, it's essential to understand what computers can do, including their devices, paper, sensors, memory, processing, and networks.

A Typical Computer System

• A typical computer system consists of an screen, keyboard, and mouse/trackpad, with variations such as desktop, laptop, and PDA.
• The devices used dictate the styles of interaction that the system supports.

Prevalence of Computers

• Computers are ubiquitous, with many devices in our homes and pockets, including PDAs, PCs, laptops, phones, cameras, TVs, and more.

Interactivity

• Long ago, computing was based on batch processing, but now most computing is interactive, with rapid feedback and user control.
• Interactivity allows users to do rather than think.

Richer Interaction

• Modern computing involves richer interaction, with sensors and devices everywhere.

Text Entry Devices

• Text entry devices include keyboards, chord keyboards, phone pads, and handwriting/speech recognition devices.

Keyboards

• Keyboards are the most common text input device, allowing rapid entry of text by experienced users.
• Keyboards have a standardized layout, such as QWERTY, but alternative designs are available.

QWERTY Layout

• The QWERTY layout is not optimal for typing, as it was designed to prevent typewriter jamming.
• Alternative designs, such as Dvorak, offer faster typing and reduced fatigue, but are not widely adopted due to the large social base of QWERTY typists.

Alternative Keyboard Layouts

• Alternative layouts, such as alphabetic and Dvorak, offer improved typing speed and reduced fatigue.
• Special keyboards, such as those designed for single-handed use or to reduce fatigue, are also available.

Chord Keyboards

• Chord keyboards have a few keys and use combinations of keypresses to type letters.
• They are compact, easy to learn, and fast, but may cause fatigue and face social resistance.

Phone Pad and T9 Entry

• Phone pads and T9 entry use numeric keys with multiple presses to type letters.
• T9 predictive entry uses a dictionary to guess the correct word, allowing fast typing.

Handwriting Recognition

• Handwriting recognition allows text input using a pen and a digitizing tablet.
• Technical problems include capturing useful information, segmenting joined up writing, and interpreting individual letters.
• Handwriting recognition is used in PDAs and tablet computers.