Human Computer Interaction Overview

Human Computer Interaction (HCI)

• Study of designing computers that best serve users.
• Closely related to User Experience (UX) design, which focuses on user satisfaction.

Technology

• Dexta haptic gloves: Mimic touch sensations in virtual reality.
• Pre-touch sensing: Predicts user actions on smartphones.
• PaperID: Digitizes paper into a touchscreen for Internet of Things (IoT) connectivity.
• Virtual reality (VR): Creates immersive simulated environments.
• Self-driving cars: Autonomous vehicles that navigate without human input.
• Touch screen technology: Interactive display technology operated by touch.

Human Capabilities

• Abilities influenced by emotions and competency.
• Visual angle: Indicates the portion of view an object occupies.
• Visual acuity: The ability to perceive detail, limited by distance.
• Size constancy: Perception of familiar objects as constant size.
• Brightness: Subjective reaction to light levels.
• Color: Composed of hue, intensity, and saturation.
• Optical illusions: Perceptual distortions due to visual system compensations.
• Saccades: Rapid eye movements between fixation points.
• Fixations: Strong interest in something or someone.

Human Language

• Syntax: Arrangement of words to form well-formed sentences.
• Semantics: Concerned with meaning and implication.
• Pragmatics: Focuses on conversational implicature.

Human Senses

• Outer ear: protects inner ear and amplifies sound.
• Middle ear: transmits sound waves as vibrations to the inner ear.
• Inner ear: chemical transmitters are released and cause impulses in the auditory nerve.
• Pitch: Sound frequency.
• Loudness: Sound amplitude.
• Timbre: Type or quality of sound.
• Auditory system: Filters sounds and can attend to sounds over background noise.
• Thermoreceptors: Receptors that sense heat and cold.
• Nociceptors: Receptors that sense pain.
• Mechanoreceptors: Receptors that sense pressure or tension.

Human Memory and Reasoning

• Reaction time: Time taken to respond to a stimulus.
• Movement time: Dependent on age, fitness, etc.
• Time taken to respond to stimulus: reaction time + movement time.
• Sensory Memory (Sensory Buffer): Buffers for stimuli received through senses.
  • Iconic Memory: Visual stimuli.
  • Echoic Memory: Aural stimuli.
  • Haptic Memory: Tactile memory.
• Short-term Memory: Acts as a scratch pad for temporary recall with rapid access (70 ms) and rapid decay (200 ms).
• Long-term Memory: Serves as a repository for all knowledge with slow access, slow decay, and a huge/unlimited capacity.
  • Episodic memory: Serial memory of events.
  • Semantic memory: Structured memory of facts, concepts, and skills.
• Decay: Information is lost gradually but very slowly.
• Retroactive interference: New information replaces old information.
• Proactive inhibition: Old information interferes with new information.
• Inductive reasoning: Assuming; can or cannot be true.
• Deductive reasoning: Derive logically necessary conclusions from given premises; logical/reasonable thinking.
• Abductive reasoning: Can lead to false explanations.
• Gestalt theory: Problem-solving form both productive and reproductive.
• Problem space theory: Problem-solving involves generating states using legal operators.

Human Errors

• Slips: Right intention, but failed to do it right.
• Mistakes: Wrong intention, misinterpreted.

Text Input Devices

• Keyboards: Most common text input device.
  • QWERTY layout: Standardized layout.
  • Dvorak layout: Common letters under dominant fingers.
  • Maltron left-handed keyboard: Specialized keyboard designed for left-handed users to reduce fatigue and improve typing efficiency.
  • Chord keyboards: Keyboards with only a few keys (four or five) where letters are typed as combinations of keypresses. Ideal for portable applications and fast typing once trained.
• T9 entry: Text input on phone keypads using numeric keys with multiple presses to input letters. Includes predictive text capabilities.
• Handwriting recognition: The input of text into a computer using a pen and a digitizing tablet. Requires natural interaction and overcomes technical challenges like interpreting different handwriting styles.
• Speech recognition: Technology that allows spoken words to be converted into text. Most successful with limited vocabularies and single users.

Pointing Devices

• Mouse: A handheld pointing device. Requires physical space and provides relative movement to control the screen cursor.
  • Mechanical mouse detection: Detects mouse motion where a ball on the underside of the mouse turns as it is moved, rotating orthogonal potentiometers to track movement.
  • Optical mouse detection: Detects mouse motion using a light-emitting diode on the underside of the mouse, detecting alterations in reflected light intensity for relative motion calculation.
• Touchpad: A small touch-sensitive tablet mainly used in laptop computers where strokes move the mouse pointer. Requires good acceleration settings for different stroke speeds.
• Trackball: A pointing device where a ball is rotated inside a static housing to move the cursor. Provides fast and accurate control, often used in gaming.
• Joystick: An indirect input device for controlling movement in games or 3D navigation. Pressure on the stick determines velocity, and buttons are used for selection.

Touch Input Devices

• Touch-sensitive screen: A display that detects the presence of a finger or stylus, allowing direct interaction. May suffer from imprecision and finger marks.
• Stylus: A pen-like pointer used for drawing directly on touch-sensitive surfaces. Commonly found in PDAs and tablet PCs.
• Digitizing tablet: A device similar to a mouse with crosshairs, used on special surfaces for accurate digitization.
• Eyegaze: An interface controlled by eye gaze direction, often used for evaluation. Requires high accuracy with potential for hands-free control.
• Cursor keys: The four keys (up, down, left, right) on a keyboard for basic motion tasks. Lack a standardized layout and are slow.

Displays

• Bitmap displays: Screens composed of a vast number of colored dots.
  • Resolution: Indicates the number of pixels.
  • Color depth: Determines the range of colors available per pixel.
• Anti-aliasing: A technique to soften edges and reduce jagged lines in digital images. Improves visual quality by using shades of line color.

Display Related Issues

• Cataracts: High incidence in VDU operators.
• Reproductive disorders: Concern over miscarriages and birth defects.

Display Technologies

• Liquid Crystal Displays (LCDs): Light passes through polarized plates, changes color with voltage.
• Random Scan: Draws lines directly, no jaggies, rarely used.
• Direct View Storage Tube (DVST): Similar to random scan but persistent, no flicker.
• Plasma Displays: Wide-screen technology, used in video walls.
• Projected Displays: Uses RGB lights or LCD projectors.
• Situated Displays: Located in public places, display or interactive.
• Digital Paper: Thin flexible sheets updated electronically.

Virtual Reality (VR)

• Virtual Reality (VR): Interacting in 3D space, using helmets and gloves.
• 3D Displays: Ordinary screens with a 3D effect, use stereoscopic vision.
• VR Headsets: Small screens for each eye, creating a 3D effect.
• VR Motion Sickness: Caued by conflicting cues, motivates technology improvements.
• Simulators and VR Caves: Projected scenes, realistic environment with physical controls.

Input/Output Devices

• Sounds: Used for error indications and confirmation of actions.
• Haptic Devices: Provide touch and feel feedback in games and simulations.
• BMW iDrive: Control menus with haptic feedback for easier selection.

Output Devices

• Printing: Image made from small dots.
  • Critical features: Resolution and speed.
• Dot-Based Printers: Include dot-matrix, ink-jet, bubble-jet, and laser printers.
• Fonts: Particular styles of text.
  • Measured in points.
• Readability of Text: Lowercase for easy reading, uppercase for individual letters.
• Serif Fonts: Helps readability in long printed text lines.
• Page Description Languages (PDLs): Converts complex pages into bitmaps for printing.
  • PostScript: Uses instructions for curves, lines, text in different styles, etc., similar to a programming language for printing.
• WYSIWYG: Acronym for “what you see is what you get,” representing the aim of word processing where the on-screen display matches the printed output.

Digital Documents

• Scanners: Devices that convert paper documents into digital images.
  • Flat-bed scanners: For whole-page scanning.
  • Hand-held scanners: For digitizing strips.
• Optical Character Recognition (OCR): Converts a bitmap image of text back into editable text. Involves segmenting text; decomposing it into lines and arcs, and deciphering characters.
• Paper-based interaction: Using paper as both output and input. Technologies like OCR, scanning, and glyphs are used for identification and control applications.

Computer Memory

• Short-term Memory (RAM): Random access memory (RAM) is a type of short-term memory stored on silicon chips with an access time of 100 nanoseconds and a data transfer rate of around 100 Mbytes/sec.
• Long-term Memory (disks): Refers to storage on magnetic disks.
  • Floppy disks: Store around 1.4 Mbytes.
  • Hard disks: Typically range from 40 Gbytes to hundreds of Gbytes.
• Flash-Memory: A type of memory used in devices like PDAs and cameras. It is silicon-based and persistent, often used for data transfer via plug-in USB devices.
• Compression: The process of reducing the amount of storage required.
  • Lossless compression: Recovers exact data.
  • Lossy compression: Recovers something similar to the original.

Storage Formats

• Text: Includes formats like ASCII, UTF-8, RTF, SGML, and XML, each serving different purposes in storing text with varying encoding and layout information.
• Media: Refers to the various formats for storing images and audio/video files.
  • Image formats: PostScript, GIF, JPEG, TIFF.
  • Audio/video formats: QuickTime, MPEG, WAV.

Computer Performance and Limitations

• Finite Processing Speed: The limitation imposed by the finite speed of processing. Can lead to issues like cursor overshooting, icon wars, and rapid scrolling through help screens.
• Moore's Law: The observation that processor speed doubles approximately every 18 months, leading to faster computers over time.
• Networked Computing: Enables access to large memory and processing capabilities, shared resources, and other people. Can face issues like network delays, conflicts, and unpredictability.

The Internet

• A brief history of the internet's growth, starting from DARPANET in 1969 to its widespread adoption. Common protocols like TCP and IP are used for communication.

Computer Systems

• INPUT DEVICES: Hardware used to provide data to a computer for interaction and control, allowing the entry of raw data for processing.
• OUTPUT DEVICES: Convert information into human-readable form, including text, graphics, tangible outputs, audio, or video.
• TEXT ENTRY DEVICES: Devices like mouse, joystick, touchpad, stylus pen, and keyboard for entering text and commands into a computer system.