Computer Interaction Quiz

Introduction

• Understanding human-computer interaction requires understanding both humans and computers.
• The current lecture focuses on how the computer's input-output devices and interface style affect interaction.
• Interactions with computers involve transferring information back and forth between the user and the computer .

A typical computer system

• A typical computer setup includes a computer box, keyboard, mouse, and screen.
• Hardware configurations vary, including desktops, laptops, and PDAs.
• These devices impact the interface's characteristics.

The Computer

• A computer system consists of various elements that influence its interaction.
• Key elements include input devices (text entry and pointing), output devices (screens, digital paper), virtual reality devices, physical interaction devices, memory (RAM and permanent media), processing speed, and networks.

Text Entry Devices

• Keyboards (QWERTY, Chord keyboards)
• Phone pads and T9 entry
• Handwriting recognition
• Speech recognition

Keyboards

• Keyboards are the most common text input devices.
• Experienced users can type rapidly using keyboards.
• Key presses send character codes to the computer.
• Keyboards are typically connected by cable but can be wireless.

The QWERTY keyboard

• The QWERTY keyboard layout is fixed, but non-alphanumeric keys may vary.
• Different national arrangements exist, such as AZERTY.

Alternative keyboard layouts

• Alphabetic (keys in alphabetical order)
• Dvorak (common letters under dominant fingers)
• Dvorak is biased toward the right hand for optimized typing efficiency
• 10-15% improvement in speed and reduction in fatigue
• QWERTY remains dominant due to user base.

Chord keyboards

• Chord keyboards use fewer keys pressed simultaneously to create letters.
• They are compact and easier to learn.
• They can achieve fast typing speeds but lack mainstream adoption.
• Microwriter is an example.

Phone pad and T9 entry

• Use numeric keys for multiple presses to type letters.
• Examples for numbers include:
  • 2-abc, 3-def, 4-ghi, 5-jkl
  • 6-mno, 7-pqrs, 8-tuv, 9-wxyz

Handwriting recognition

• Handwriting is a common text entry method, but translation to digital text is challenging.
• Technology struggles with accuracy due to individual variations in handwriting
• Effective recognition involves capturing letter strokes, not just shapes
• Online recognition is typically more effective than analyzing static paper handwriting

Speech recognition

• Speech recognition is a promising text entry method.
• Its appeal lies in its intuitive interaction.
• Challenges involve understanding natural language, vagueness, interruptions, and individual speech patterns.
• System training is required to handle various accents and emotional states.
• Specific areas like telephone systems, accessibility, and hands-occupied tasks utilize speech technology.

Numeric keypads

• Used for quick number entry (calculators, PCs, ATMs).
• Telephones and ATMs use numeric keyboards with different layouts.

Positioning, Pointing And Drawing

• Pointing devices are crucial in modern computing, especially in CAD.
• These devices allow for precise screen positioning and selection.
• Common pointing devices include mice, touchpads, trackballs, joysticks, touchscreens, tablets, eye gaze systems, and cursors.
• Drawing accuracy varies depending on the device.

The Mouse

• The mouse is a standard pointing device.
• It moves a pointer (the cursor) on the screen.
• Mouse movement controls the cursor.
• The mouse has several buttons, typically 1 to 3, for making selections, initiating operations, etc.

Touchpad

• Touchpads are touch-sensitive tablets.
• Typically 2-3 inches square.
• Used extensively in portable laptops, replacing the mouse.
• Operated by stroking a finger or stylus over the surface.
• Often simulate a trackball .

Trackball and thumbwheel

• The trackball is similar to an inverted mouse.
• A weighted ball rotates to move the cursor.
• They are compact.
• Less suitable for drawing compared to a mouse.
• Trackballs and thumbwheels are inexpensive but have slow or limited movement.

Joystick and keyboard nipple

• A joystick is an indirect input device with a stick or grip.
• Its movements control the screen cursor's corresponding actions.
• Typically used in computer games.

Touch-sensitive screens

• Touchscreens offer direct interaction and no separate pointing device.
• Technologies include interrupting light beams, detecting capacitance changes, and ultrasonic reflections.

Stylus and light pen

• Stylus: small pen-like pointer drawn directly on the screen; detects input with various methods.
• May use touch-sensitive surface or magnetic detection.
• Light pen: now rarely used; detects the light from a screen to determine their location.

Digitizing tablet

• A specialized device for freehand drawing.
• May be used as a mouse substitute or text input using OCR.

Eyegaze

• Eyegaze systems use special glasses or built-in sensors to control the computer via eye movement.
• Detects eye to determine intended direction of action
• Fast and accurate but costly.

Cursor keys

• Four keys (up, down, left, right) on the keyboard.
• Basic cursor movement for text editing.
• Can be used for various tasks.
• Not standardized in layout; inverted "T" is common.

Discrete Positioning Control

• Used in phones, TV controls, etc.
• Cursor pads, mini joysticks, discrete left-right/up-down movement used for menu selections.

Display Devices

• Bitmap screens (CRT & LCD)
• Large displays and situated displays
• Digital paper.

Bitmap Displays

• Most computer displays use a bitmap, a grid of colored dots (pixels).
• Resolution and color depth impact visibility.
• Screen size and bits per pixel define color and resolution possibilities.

Bitmap Displays Cont..

• Resolution and the number of colors affect display quality.
• Lower resolutions on a high-resolution device lead to stretched screens.
• LCD screens have a pixel density and use a black border to resolve issues of lower resolution.

Health hints

• Avoid sitting too close to the screen.
• Use larger fonts.
• Take breaks from extended screen work.
• Work in a well-lit area to avoid strain.
• Be extra careful if pregnant.

Liquid crystal displays

• LCDs are smaller, lighter, and have no radiation concerns.
• Used in various devices (PDAs, portables, notebooks, digital watches, mobile phones, HiFi controls).
• Technology involves a transparent top plate, a polarized bottom plate, and light passing through the crystal.
• Voltage changes the crystal's polarization, resulting in different colors.
• Light reflected to the eye; not emitted, results in less eye strain.

Large displays

• Large displays use various technologies.
• Gas plasma is commonly used in displays with a 16:9 aspect ratio.
• Suitable for lectures, meetings, and public displays to share information.

Digital paper

• A newer "display" technology, still emerging.
• Thin flexible materials that are written electronically.
• Maintains information outside of an electrical supply.
• Aim is to make programmable sheets to be used as a printout.

Physical Controls and Sensors

• Includes touch, feel, sound, and smell.
• Physical controls are device-specific controls, like buttons or knobs.
• Bio-sensing are sensors used to detect various environmental changes and user actions.

Sound output

• Auditory signals accompany screen displays for feedback.
• Beeps, clanks, and whistles from keyboards, and telephone keypads provide essential feedback.

Touch, feel, and smell

• Haptic devices enhance interaction and simulation of tactile sensations.
• Texture perception and smell triggers still are being explored for better immersion.

Physical controls

• Dedicated control panels are designed for specific functions.
• Microwave ovens are commonly used as examples of physical controls.
• These controls' design is for ease of use and cleanliness.

Environment and bio-sensing

• Sensors are routinely used to control functions based on presence, movement, or location.
• These include elements that control water flow in washrooms or automatic doors.

Paper: Printing And Scanning

• Print technology (fonts, page description languages like WYSIWYG)
• Scanning and Optical Character Recognition (OCR) allow converting physical documents to digital formats.

Printing

• Dot-based technologies use dots to create printed images.
• Resolution is measured in dots per inch (dpi).
• Key factors include resolution, dot size and spacing, printing speed(ppm), and costs.

Types of Printers

• Inkjet printers (ideal for home and small offices, used for photo printing and general versatility)
• Laser printers (common in offices, used for high-speed, high-volume prints, primarily text)
• Dot matrix printers (used in specialized tasks for multipart forms, receipts, etc.)

Fonts

• Fonts are a text's particular style.
• Font sizes are measured in points.
• Common font types include Courier, Helvetica, Palatino, and Times Roman.
• Character width (fixed pitch or variable pitch).
• Serif or sans serif font styles affect readability.

Readability of text

• Lowercase letters are easier to read than uppercase ones.
• Font shape and size affect readability.
• Serif fonts generally work well for printed text, while sans serif fonts are often better for displaying text.

Page Description Languages

• PDLs are used to program and describe the layout, design and formatting of documents.
• They are essential for document creation, ensuring consistent appearance across various devices.
• Examples include PostScript, PDF, HTML/XHTML, and PCL.

Scanners

• Scanners transform physical objects such as documents, photos, and artwork into digital images.
• Two main types: flatbed and handheld.
• Flatbed are generally best for larger documents, while handheld are ideal for scanning smaller documents in a portable manner.

Applications of Scanners

• Applications include document management, archiving, graphic design, medical imaging, and education.

Memory

• Short-term memory is RAM (random access memory); often measured in gigabytes.
• Long-term memory utilizes magnetic and optical disks for persistent data storage.
• Key factors include speed, capacity, and formats.

Short-term Memory - RAM

• RAM is volatile memory; data is lost when the power is off.
• Ideal for active processes requiring quick access.
• Typically measured in gigabytes (GB) or terabytes (TB)

Long-term Memory - disks

• Persistent storage (data remains when the computer is off).
• Magnetic disks (HDDs) provide large capacity.
• Optical disks (CDs, DVDs, Blu-rays) are durable and portable.

Speed and capacity

• Speed refers to data transfer rate of storage devices.
• Capacity refers to the data storage capacity of storage devices.

Compression

• Compression reduces file size to improve storage space and transmission speed.
• Lossless compression preserves all information; lossy compression discards some data.

Storage formats - text

• Text formats range from plain text to complex formatted structures.
• Plain Text (.txt), Rich Text Format (.rtf), HyperText Markup Language (.html), and Portable Document Format (.pdf) are common text formats.

Storage formats - media

• Image formats include JPEG/JPG, PNG, and GIF.
• Audio formats include MP3 and WAV.
• Video formats include AVI and MP4.

Processing and Networks

• Finite processing speed impacts UI design.
• Networked computing enables sharing resources and facilitates communications.

Finite processing speed

• Processing speed influences user interactions (e.g., delays in actions).
• Two common faults relate to slow and fast processing.
• Slow processing causes delays; fast processing can lead to erratic behaviors and multiple clicks occurring at once.

Networked computing

• Networked computing connects multiple computers and devices enabling communication and collaborative activities.

The internet

• The internet is a global network.
• Its components include protocols such as HTTP, HTTPS, TCP/IP, FTP, SMTP, and DNS.

Test your knowledge on the fundamental concepts of human-computer interaction. This quiz covers the primary goals of interacting with computers, components of a computer setup, and the influence of input and output devices. Challenge yourself with questions about virtual reality and hardware configurations.