Human Computer Interaction

Transcription

1 Human Computer Interaction Chapter #1. HCI: is discipline concerned with study, design, construction and implementation of human centric interactive computer systems. Usability goals & measures Usability Goals: 1. Effectiveness. 2. Efficiency. 3. Satisfaction. Usability Measures: 1. Time to learn. 2. Speed of performance. 3. Rate of errors by users. 4. Retention over time. 5. Subjective satisfaction. Life-critical systems: Air traffic control, nuclear reactors, power utilities, police & fire dispatch systems, medical equipment. High costs, reliability and effectiveness are expected. Industrial and commercial uses: Banking, insurance, order entry, inventory management, reservation, billing, and point-of-sales systems. Ease of learning is important to reduce training costs. Speed of performance is important because of the number of transactions. Home, and entertainment applications: personal computer applications, include clients, search engines, cell phones, digital cameras, and music players. Ease of learning, low error rates, and subjective satisfaction are paramount due to use is often discretionary and competition fierce Exploratory, creative, and collaborative systems: web browsing, search engines, artist toolkits, architectural design, software development, music composition, and scientific modeling systems. Collaborative work. Social-technical systems: complex systems that involve many people over long-time periods. Voting, health support, identity verification, crime reporting. Ease of learning for novices and feedback to build trust. 1

2 Human cognitive processes: Long-term and semantic memory Short-term and working memory Problem solving and reasoning Decision making and risk assessment Language communication. Search, imagery, and sensory memory Learning and skill development. Cultural and international diversity Characters, numerals, special characters Date and time formats Numeric and currency formats Weights and measures Telephone numbers and addresses Users with Disabilities The flexibility of desktop, web, and mobile devices make it possible for designers to provide special services to users who have disabilities. Older Adult Users Understanding the human factors of aging can help designers to create user interfaces that facilitate access by older adult users. Children Another lively community of users is children, whose uses emphasize entertainment and education. When they become teenagers, they may become highly proficient users who often help their parents or other adults. HCI Goals Influencing academic and industrial researchers. providing tools, techniques, and knowledge for commercial Designers. Raising the computer consciousness of the public. 2

3 Chapter #2. Guidelines A guidelines document helps by developing a shared language and then promoting consistency among multiple designers in terminology usage, appearance, and action sequences. Guidelines for Navigating the interface Use thumbnails to preview large images. Ensure that embedded links are descriptive. Use unique and descriptive headings. Use check boxes for binary choices. Accessibility guidelines Text alternatives. Provide text alternatives for any non-text content. Time-based media. Provide alternatives for time-based media (movies or animations). Distinguishable. Make it easier for users to see and hear content. Predictable. Make web pages appear and operate in predictable ways. Getting the user's attention Intensity. Use two levels only, with limited use of high intensity to draw attention. Marking. Underline the item, enclose it in a box, point to it with an arrow. Size. Use up to four sizes, with larger sizes attracting more attention. Choice of fonts. Use up to three fonts. Color. Use up to four standard colors, with additional colors reserved for occasional use. Principles: more fundamental widely applicable and enduring, need more clarification. Fundamental principles: 1- Determine user s skill levels, 2- Identify the tasks. Determine user s skill levels Novice or first-time users. Knowledgeable intermittent users. Expert frequent users. Identify the tasks: choose the interaction styles Direct Manipulation Menu selection Form fill-in Command language Natural language 3

4 Theories: Well substantiated explanation of some aspect of phenomenon. o Descriptive theories: Developing consistent terminology o Explanatory theories: Describing sequence of activities o Prescriptive theories: Giving designers clear guidance for choices o Predictive theories: Enable designers to compare proposed designs for execution time or error rates. Theories are according to Perceptual, Cognitive, & Motor Skills Motor skill performance theories: are well established and accurate for predicting key stroking or pointing times. Perceptual theories: have been successful in predicting reading times for free text, lists, formatted displays, and other visual or auditory tasks. Cognitive theories: involving short term, working, and long-term memory, are central to problem solving and play a key role in understanding productivity as a function of response time. Design-by-Levels The conceptual level is the user's "mental model" of the interactive system. The semantic level describes the meanings conveyed by the user's input and by the computer's output display. The syntactic level defines how the user actions that convey semantics are assembled into complete sentences that instruct the computer to perform certain tasks. The lexical level deals with device dependencies and with the precise mechanisms by which users specify the syntax. Consistency Consistency theory: Important goal for designers, used for objects and actions/commands, color, layout, icons fonts, etc... If objects and actions was orderly describable by few rules, users will be able to learn and retain them easily. 4

5 Chapter #3. Direct manipulation Visibility of objects and actions of interest, Rapid, reversible, incremental actions, and replacement of typed commands by pointing action. Examples: - o Office Automation o Spatial Data Management System Geographic applications, seems natural to give a spatial representation in the form of a map that provides a familiar model of reality. o Video Games o Computer Aided Design Computer-Aided Design (CAD) systems for automobiles, electronic circuitry, aircraft, or mechanical engineering. Computer-Aided Manufacturing (CAM) Process Knowledge System provides the manager of an oil refinery, paper mill, or power-utility plant. Teleoperation: indicates operation of a system or machine at a distance. Telemedicine (medical care): physicians examine patients, remotely and surgeons carry out operations across continents. Telepathology: pathologist examines tissue samples or body fluids under a remotely located microscope. Virtual colonoscopy: Allow patient to undergo a CT scan as opposed to a more invasive procedure, the physician can then interactively navigate through a 3D model Robotic surgery: Alternative to conventional surgery that enables a smaller incision and more accurate and precise surgical movements. Military: o Commonly used by the military and by civilian space projects o Operations using unmanned aircraft o Teleoperated missile firing aircraft Complicating factors in the architecture of remote environments: Time delays. Incomplete feedback. Unanticipated interferences. 5

6 Chapter #4. Virtual reality: is a high-end user-computer interface that involves real-time simulation and interaction through multiple sensory channels. Has four Elements: 1- Virtual World: An imaginary space. 2- Immersion: Having a sense of presence within an environment. 3- Sensory feedback. 4- Interactivity. VR systems types Immersive VR (Artificial Reality) Telepresence Augmented reality Desktop reality. Artificial reality and CAVE The CAVE: a room with several walls of high resolution rear projected displays with three-dimensional audio. Advantages: - 1- A wide surrounding field of view. 2- Ability to provide a shared experience to a small group. Telepresence: is a computer-generated environment consisting of interactive simulations and computer graphics in which a human experiences presence in a remote location. Augmented reality: Enables users to see the real world with an overlay of additional information. Desktop virtual reality: Also called fish tank virtual environments, both references are to standard "looking-at" display. Technologies for Successful virtual environments Visual Display Head position sensing Hand-position sensing Force feedback & Haptics Sound input and output Cooperative and competitive virtual reality 6

7 Chapter #5. Speech and auditory interfaces: have five technologies Speech store and forward. Discrete word recognition. Continuous speech recognition. Voice Information system. Speech generation. obstacles to speech recognition Increased cognitive load compared to pointing. Interference from noisy environment. Unstable recognition. obstacles to speech output Slow. Ephemeral. Difficulty in searching. Discrete word recognition. Recognize individual words spoken by a specific person; can work with 90- to 98% reliability for 10 to 10,000 word vocabularies. Continuous-speech recognition Challenges: o Difficulty in recognizing boundaries between spoken words o Normal speech patterns blur boundaries o Diverse accents o Variable speaking rates o Disruptive background noise o Challenging emotional intonation Applications: o Enable users to dictate letters and compose reports verbally for automatic transcription. o Enable automatic scanning and retrieval from radio or television programs, court proceedings, lectures, or telephone calls for specific words or topics. Examples: o IBM ViaVoice speech-dictation system o Dragon - NaturallySpeaking Medical system 7

8 Voice Information System Interactive Voice Response (IVR): can provide good customer service at low cost. Telephone based speech systems enable storing and forwarding of spoken messages with user commands entered with keyboards. (e.g.: WhatsApp). Audio books have been successful allow users to control the pace, while conveying the curator s enthusiasm or author s emotions. Speech generation used in Automobile Navigation System, Internet services, Utility Control rooms and Children's games. Applications for Blind: o Text-to-speech utilities like the built-in Microsoft Windows Narrator. o Screen readers like Freedom Scientific s JAWS. Speech synthesis is technologically feasible. Algorithms are used to generate the sound (speech synthesis) and the intonation may sound robot-like and distracting. Web-based voice applications. Displays Small and Large: The display has many important characteristics, including: o Physical dimensions (usually the diagonal dimension and depth) o Resolution (the number of pixels available) o Number of available colors, color correctness o Luminance, contrast, and glare o Power consumption o Refresh rates (sufficient to allow animation and video) o Cost o Reliability Display technology Raster-scan cathode-ray tube (CRT): electron beam sweeping out lines of dots to form letters Liquid-crystal displays (LCDs): Thin film, light weight, low electricity consumption Plasma Displays: Flat profile, consume more electricity Light-emitting diodes (LEDs): Used in large public displays, curved displays Organic Light-emitting diodes (OLEDs) 8

9 o Durable & energy efficient o Laid on flexible plastic or metallic foil o Used with wearable or roll-able displays Electronic ink technology: Paper-like resolution Tiny Projectors Micro vision Pico projectors: Project color images on the wall from mobile devices Braille displays: for the blind users Large Displays o Large Informational Wall Displays Applications: Military command operations Utility Management Emergency response o Interactive Wall Displays Simpler digital whiteboard systems, such as the SMART Board, provide a large touch-sensitive screen on which a computer image is projected. the functionality is identical the desktop machine, using users' fingers as pointing devices. o Multiple desktop displays Users sitting at their desks and connect computers to have a larger number of windows and documents visible at the same time and reached by the mouse. Heads-up display: Project information on the partially silvered windscreen of an airplane or car. Helmet mounted display: A helmet/head mounted display (HMD) moves the image with the user. Mobile device displays: Optimize for repetitive tasks, Web browsing difficult, Okay for linear reading. 9

10 Chapter #6. Collaboration VS Social media Characteristics Collaboration Social Media 2 to 2000 People 20 to People Work related, goal directed playful, process Oriented Time limited, milestone Open ended Selected Partners Unknown Partners Assign task and review work. Act independently Examples:- Goals of Collaboration Focused partnerships Lecture or demo Conference Structured work processes Meeting and decision support Electronic commerce Tele-democracy: allows small organizations, professional groups, and city, state, or national governments to conduct online town-hall meetings, to expose officials to produce consensus through online conferences, debates, and votes. Online communities: groups of people widely distributed graphically, across time zones. These people come online to discuss, share information, socialize, or play games. Collaboratories Telepresence 10

11 Time/space matrix model of group-supported work Asynchronous distributed interfaces: Different place, different time Electronic mail ( ): The atomic unit of collaboration for users is the message. List Servers: a popular community structure is a listserver, to which individuals must subscribe to receive notices of new messages. ex:- LISTSERV. Yahoo! Google Groups: focused electronic discussions by group of people. o In large discussion groups, most users read and do not post; they are silent members who are known as lurkers. Blogs: are open electronic documents or diaries that are owned by their creators, but readers can contribute comments. o Blogs can focus on any topic; popular themes include politics, music, popular literature, travel film critiques, and personal diaries. Wikis: are collaborative web pages that are open for anyone to add or revise content, unless they are limited to members who must supply a password. o Wikipedia is a collaborative encyclopedia developed by people from over 40 countries and in over 250 different languages. o Wikinomics has Three conditions: 1- The cost for contribution is low 2- Tasks are easily broken into manageable pieces 3- The cost of integration and quality control is low 11

12 Microblogging: people use this to talk about their life as it happens, in short bursts. E.g. Twitter, Tumblr. Online Communities for Distance Education: supplements to face-to-face classes because they stimulate lively educational experiences. Synchronous distributed interfaces: Different place, same time Shared screens allow teachers and trainers to present web seminars (webinars or webcasts) from their homes with audio accompaniment and video windows while thousands watch their slides and demonstrations from anywhere that they can find an Internet connection. Chat, instant messaging, and texting Instant massage(im): Popular alternative to open chat rooms, in part because membership can be tightly controlled. E.g. Facebook, Microsoft, and Yahoo! Audio and videoconferencing o Standard telephones, cell phones for audio conferencing. o Videoconferencing platforms: Polycom, Sony, TANDBERG and HP Holo. Face-to-face interfaces: Same place, same time Teams of people often work together in the same room and use complex shared technology Electronic Meeting rooms, Control rooms and Public Spaces: o Shared display from lecturer workstation o Brainstorming, voting, and ranking o File sharing o Shared workspace o Group activities o SMART Board o Public spaces facilitate sharing Electronic classrooms o Teaching Learning theaters face-to-face collaboration. o Changes teaching style. o Small group collaborative-learning experiences. 12

13 Chapter #7. Quality of Service QoS can be measured in terms of telephone call quality, lost connections, customer satisfaction, connection time, cost, and other factors. Models of response-time impacts Response time: number of seconds from the moment users initiate an activity until the computer presents results. User think time: The number of seconds the user thinks before entering the next action. HCI designers must consider: o complex interaction of technical feasibility o costs o task complexity o user expectations o speed of task performance o error rates o error handling procedures Rapid task performance, low error rates, and high satisfaction can come from: o Knowledge of the objects and actions necessary for the problem-solving task. o Solution plan can be carried out without delays. o Distractions are eliminated. o Feedback given. o Errors avoided or easily handled. Other conjectures in choosing the optimum interaction speed o Novices perform better with slower response time o With little penalty for an error, users prefer to work more quickly o Users prefer rapid action, when task is familiar and easily comprehended o If users have experienced rapid performance previously, they will expect in future situations 13

14 Expectations and attitudes Previous experiences. Individual personality differences. Task differences. User productivity Repetitive tasks o Nature of the task has a strong influence on whether changes in response time alter user productivity o Shorter response time means users responds more quickly, but decisions may not be optimal o reduced response time lead to more productivity o slower response time lead to more accuracy Frustrating experiences Sources of user frustration with contemporary user interfaces include: o User frustration originated from interface complexity, network disruptions, and malicious interferences o When hard-to-use computers can affect workplace productivity, users' moods, and interactions with other coworkers. o Interruptions appear to be troubling to users o Memory as an indication of where frustration occurs while using technologies such as operating systems, web browsers, text editors, clients, mobile devices, digital video recorders, and others o User frustration with mobile devices over the years o has become the source of frustrating "spam" o Another frustrating problem for users is the prevalence of malicious viruses. The top causes of frustration reported were: o page layout causing confusing screen-reader feedback; o conflict between the screen reader and the application; o poorly designed/unlabeled forms; o no alternative text for pictures; and o a three-way tie between misleading links, inaccessible PDFs, and screen-reader crashes. 14

15 Chapter #8. Information visualization: the use of interactive visual representations of abstract data to amplify cognition. The abstract characteristic of the data is what distinguishes information visualization from scientific visualization. Information visualization: categorical variables and the discovery of patterns, trends, clusters, outliers, and gaps Scientific visualization: continuous variables, volumes and surfaces visual data mining: is emerging area of data mining. visual-information seeking mantra: as information visualization matures, guidelines, principles, and theories will emerge for this area. the seven data types of information visualization. 1-1D linear data: Linear data types are one-dimensional; include source code, text, dictionaries, and alphabetical lists of names. 2-2D map data: Planar data include geographic maps, floor plans, and newspaper layouts. 3-3D world data: Real-world objects, such as molecules, the human body, and buildings, have volume and complex relationships with other items. 4- Multidimensional data: Most relational- and statistical-database contents can be conveniently manipulated as multidimensional data, in which items with n attributes become points in a dimensional space. 5- Temporal data: Time series are very common e.g. weather data. 6- Tree data: Hierarchies or tree structures are collections of items in which each item has a link to one parent item. 7- Network data: items can be linked to an arbitrary number of other items in a network. The seven basic tasks 1. Overview task - users can gain an overview of the entire collection 2. Zoom task - users can zoom in on items of interest 3. Filter task - users can filter out uninteresting items 4. Details-on-demand task - users can select an item to get details 5. Relate task - users can relate items within the collection 6. History task - users can keep a history of actions to support undo, replay, and progressive refinement 7. Extract task - users can allow extraction of sub-collections and of the query parameters 15

16 Challenges for Information Visualization Importing and cleaning data. Combining visual representations with textual labels. Finding related information. Viewing large volumes of data. Integrating data mining. Integrating with analytical reasoning techniques. Collaborating with others. Achieving universal usability. Evaluation. 16