Computer Setup and Human-Computer Interaction

Introduction

• Human-computer interaction requires understanding both humans and computers.
• Previous lectures focused on human capabilities and behaviour.
• This lecture focuses on input-output devices and how technology influences interaction and interface style.
• Interaction involves transferring information between the user and computer.

A typical computer system

• A typical setup includes a computer box, keyboard, mouse, and color screen.
• Variations exist based on hardware configurations (desktops, laptops, PDAs).
• These devices influence the interface characteristics.

The Computer System

• A computer system comprises various elements, each affecting interaction.
• Input devices include text entry and pointing.
• Output devices include screens, digital paper, virtual reality (VR), and physical interaction.
• Memory involves RAM and permanent media, including capacity and access.
• Processing involves speed, networks and other components.

Text Entry Devices

• Keyboards (QWERTY et al.): most common text input device, allowing experienced users rapid entry.
• Keypresses cause character codes to be sent; typically connected by cable, but can be wireless.
• Chord keyboards use few keys for simultaneous pressing to represent letters.
• Phone pad and T9 entry utilizes numeric keys for multiple presses.
• Handwriting recognition: translates handwriting into digital text but is challenging due to accuracy and individual variations in handwriting style.
• Speech recognition: converting speech to text, a promising but limited method due to vagueness, imprecision of spoken langauge, accents and other variations.

Keyboards (Specific)

• QWERTY keyboard layout is fixed but non-alphanumeric keys vary.
• Other keyboards (e.g., AZERTY) use different letter arrangements for specific countries.
• Variations exist in bracket, backslash and other symbol placements between keyboard designs.

Alternative Keyboard Layouts

• Alphabetic keyboards arrange keys in alphabetical order but typically not faster for trained typists.
• Dvorak layout positions common letters under dominant fingers, potentially improving speed & reducing fatigue.
• However, QWERTY's widespread adoption prevents significant change.

Chord Keyboards

• Differ greatly from traditional keyboards, using few keys, pressing simultaneously to represent letters.
• Often more compact and easier to learn, achieving fast typing speeds.
• Suitable for one-handed use in confined spaces.

Phone Pad and T9 Entry

• Using numeric keys, with multiple presses to represent letters, characters.
• Allows surprisingly fast text entry given the method.

Handwriting Recognition

• Handwriting is a familiar method but conversion into digital text is challenging.
• Accuracy is affected by individual handwriting variations, and effective capture requires understanding how letters are drawn, not just their shape.

Speech Recognition

• Speech recognition is a promising method for text entry.
• Its appeal lies in the intuitive nature of interacting through speech.
• Challenges include vagueness, imprecision, and pauses in natural speech, and training is needed for unique speech patterns.

Numeric Keypads

• Used for quickly entering numbers (e.g., calculators, PC keyboards, ATMs).
• Telephones have numerical keypads with varying layouts from calculators, and PC keyboards.

Positioning, Pointing and Drawing

• Pointing devices (e.g., mouse, trackpad, trackball, joysticks, etc.) are essential in modern computing.
• Drawing and pointing use different skills compared to tools like pencils.

The Mouse

• The mouse is a major component for desktop computer systems, moving a pointer (cursor) on the screen.
• It features planar motion and buttons (selection/initiation).
• Sometimes located on desktops it takes a physical space.
• Footmouse devices offer a way for hands-free interaction with a cursor, but are not widely adopted.

Touchpad

• Touchpads are touch-sensitive tablets often used in laptops and notebooks.
• They operate by detecting finger movements and are similar to a simulated trackball.
• 'acceleration' settings are crucial for good usability.

Trackball and Thumbwheel

• Trackballs function like inverted mice (rotate a weighted ball to control the cursor).
• Compact, but less effective for drawing long movements compared to trackpads.
• Trackballs and thumbwheels vary in size and usability, and are especially useful in gaming or specialized applications.
• Thumbwheels often provide quick horizontal/vertical movement.

Joystick and Keyboard Nipple

• Joysticks are indirect input devices, taking up little space.
• Pressure on a stick corresponds to velocity and movement of cursor.
• Joysticks are often used in computer games and other applications involving aircraft/3D navigation

Touch-sensitive Screens (Touchscreens)

• Direct method for pointing and selecting objects on screen using touch (fingers or stylus).
• Operate through various technologies (e.g. light beams, capacitance).
• Fast and direct interaction is ideal for making menu selections & controlling a wide range of variables.

Stylus and Light Pen

• Stylus: small pen-like pointer use to draw/select on screen.
• Often functions with touch-sensitive displays and magnetic detection.
• Light Pen: now rarely used, uses light from the screen to detect location.
• Stylus/Light Pen are direct and easy to use in applications requiring drawing or precise selection.

Digitizing Tablet

• Specialized device used for freehand drawing, acting as a mouse alternative, especially for high-precision tasks.
• Supports text input with recognition software.

Eyegaze System

• Control the computer by detecting where the user looks.
• Typically uses special glasses or a head-mounted device.
• Fast and accurate but can be costly, typically used for selection instead of drawing due to the lack of smooth eye movement.

Cursor Keys

• Four directional keys on a keyboard.
• Very inexpensive but slow option for cursor movement.
• Common for text editing tasks.

Discrete Positioning Control

• Used in phones, TV remote controls, etc.
• Employ cursor pads or mini-joysticks for discrete directional movements.
• Primarily for menu selection.

Display Devices

• Bitmap screens (CRT & LCD): used for displays of vast numbers of coloured dots or pixels based on a grid.
• Large displays (e.g. LCD touch screen): large displays are now found in public places and businesses to view or interact simultaneously.

Bitmap Displays

• Practically all computer displays are based on bitmaps, showing vast numbers of coloured dots or pixels.
• The larger the number of bits per pixel, the more color or intensity possibilities.
• Resolution is important, and is measured in dpi(dots per inch). The relationship between screen resolution, image resolution, and output/input devices must be considered for optimal performance and user experience.

Bitmap Displays (Continued)

• Resolution and color are important measures for bitmap displays.
• Resolution is important measure of the displays and is useful for comparing and choosing output devices. It's also important for comparing and choosing the right output device.

Health Hints (Related to Computer Usage)

• Avoid sitting too close to the screen, using very small fonts, viewing the screen for extended periods without breaks, placing the screen in front of bright windows.
• Ensure proper posture and ergonomics while working on the computer.
• Excessive stress and potential pregnancy factors should also be considered when using computers or devices.

Liquid Crystal Displays (LCDs)

• Smaller, lighter, and free from radiation problems.
• Increasingly used in PDAs, laptops, and desktop devices, as well as smaller items such as digital watches, mobile phones, and HiFi controls.
• Use top and bottom plates, polarized lights, and polarisation to create different colours and display images.

Large Displays

• Several types of large displays exist (plasma, etc.).
• Behave like regular screens but are large, usually have HDTV wide-screen format.
• Employed for lectures, meetings, in public places where multi-viewers want to see or interact.

Digital Paper

• Emerging technology that is digital, yet has a paper-like feel.
• Thin, flexible materials function similarly to interactive computer screens, retaining information even without a power source.

Physical Controls and Sensors

• These devices use various senses like touch, sound, feel and smell to interact with a computer.
• Examples include: sound output, touch, feel, and smell.
• Sensors in public washrooms activate water when hands are placed under the tap.

Sound Output

• Auditory signals improve user experience and interaction.
• Beeps, clanks, and whistles provide system feedback.
• Key presses and commands often generate key-specific auditory feedback, making it an important part of interactive systems.

Touch, Feel and Smell

• In typical uses, these senses are rarely utilised, but computer games frequently employ input methods for these senses.
• Examples of haptic devices include joysticks and steering wheels (force feedback) enabling realistic simulations of actions.

Physical Controls

• Desktop computers often use generic keys for multiple functions.
• Dedicated control panels serve specialized devices/single uses, leading to specific design choices.
• Microwave ovens, as an example, utilize flat, easy-to-clean panels for enhanced user experience.

Environmental and Bio-sensing

• Sensors for tasks such as controlling public washroom water flow, automatically controlling lights, security tags, or environmental monitoring.
• Sensors measure various variables, including temperature, movement, location, and weight.

Paper: Printing and Scanning

• Print technology, Fonts and page description, WYSIWYG and OCR/scanning methods for printing.

Printing

• Popular printing techniques use dots to build images.
• Dot resolution, or dpi (dots per inch), is a critical measure to determine the clarity of a print.
• Print quality is also affected by dot size, printhead operations and offset printheads.
• Critical features of print technologies measure resolution, dot size/spacing, and print speed. Cost factors, like initial purchase price, maintenance, and operational, are also significant.

Types of Printers

• Inkjet printers are ideal for home or small office use.
• Laser printers are fast, effective for high-volume printing, and are common in offices.
• Dot matrix are used in specific tasks like printing or specialized forms.

Fonts

• Font refers to the stylistic characteristic of text.
• Common font styles include Courier, Helvetica, Palatino, and Times Roman, including their sizes, pitch, serifs and other specific characteristics.

Readability of Text

• Lowercase helps readability and word separation.
• Using numerals consistently in the same format.
• Font and character style are significant in readability, particularly for lines of lengthy text.

Page Description Languages (PDLs)

• Specialized programming languages for describing page layout, content, and appearance.
• Essential for desktop publishing, printing, and digital documents, guaranteeing consistent formatting and appearance across different devices.
• Common examples include PostScript, PDF, HTML, XHTML and PCL.

Scanners

• Scanners convert physical objects (documents, photos) into digital images for storage, sharing, or editing.
• Types include flatbed and handheld scanners.
• Flatbed scanners excel at handling different-sized documents, whereas handheld scanners are portable.

Application of Scanners

• Document management, archiving, graphic design, medical imaging, and educational use are all significant applications of scanners.

Memory

• Short-term memory (RAM) and long-term storage devices (e.g., magnetic & optical disks).
• Speed, capacity and compression techniques for memory.

Short-term Memory – RAM

• RAM (Random Access Memory) temporarily stores data required by the CPU and other processes.
• RAM is volatile, meaning it loses data when power is cut.
• Its high speed and capacity make it ideal for temporary data usage.
• Measured in gigabytes (GB) or terabytes (TB).

Long-term Memory – Disks

• Magnetic and optical disks offer persistent storage, retaining information even when the computer is off.
• Magnetic disks (hard drives), staple for decades, offer high capacity and cost effectiveness.

Speed and Capacity

• Speed refers to how quickly data can be read or written.
• Capacity is the amount of data that can be stored.
• Measured in gigabytes (GB) or Terabytes (TB).

Compression

• Reducing file size while maintaining or approximating the original information.
• Two categories: lossless (no data loss) and lossy (data approximation).

Storage Formats - Text

• Essential for representing, storing, and exchanging textual data between various platforms.
• Different formats include plain text, rich text formatting (RTF), markup language (HTML), and portable document format (PDF).

Storage Formats - Media (Images, Audio & Video)

• Common formats include JPEG, PNG, GIF, MP3, WAV, MP4, and AVI, covering image, audio and video data.

Processing and Networks

• Finite speed of computers, limits of interaction, and network computing.

Finite Processing Speed

• Speed influences user interface, causing slow processing issues.
• Problems like incorrect line drawing, inconsistent responsiveness and lag in text editors are common when handling large processing tasks.

Finite Processing Speed (Continued)

• Fast processing speed problems, like chaotic screen behavior or sudden swapping of multiple actions /programs.

Networked Computing

• Networking multiple computers or devices, enabling communication and task collaboration.
• Key benefits include sharing resources, enhancing communication, increasing scalability, and increasing flexibility.

The Internet

• Global network connecting multiple private, public, academic, business and government networks for information exchange, communication, and access to resources.

Internet Protocols

• Common protocols include HTTP (transferring web pages), HTTPS (secure web page transfers), TCP/IP (fundamental internet communications), FTP (transferring files), SMTP (sending email), and DNS (human-readable web addresses to numerical IP addresses).

Explore the fundamentals of computer setups and user interaction in this quiz. Understand the essential components like input devices and the significance of hardware configurations. Test your knowledge on the goals of human-computer interaction.