Social Context of Computing.pdf

Operational Definition of Context “Context is any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and the application themselves....

Operational Definition of Context “Context is any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and the application themselves.” [Dey and Abowd, 2000] Observations -From point of view of developer Active Badges Application: help operator forward calls to researcher at appropriate location Entity Characteristic Info (context) Researcher Badge ID/Name, location, ?Time of the workday (morning, lunch, dinner)? Room Presence of a phone Museum Audio Guide Example Application: digital museum guide Entity Characteristic Info (context) Museum Patron (user) Museum Audio Guide Example Application: digital museum guide Entity Characteristic Info (context) Museum Education, age, spoken Patron (user) language, location in museum, previously viewed artifacts Exhibit What area of museum Mobile battery life Interface Context Categories Recall Dey’s goal: operational definition for use by designers and developers Once you have entities, want to identify frequently useful contexts Primary Categories ◦ Answer basic questions like who, what, when, where ◦ Index into more detailed secondary categories Secondary Categories ◦ More specific details that may be relevant Primary Categories Identity: every entity has a unique id Location: position, spatial relationships (latitude/longitude, with friends, near a Starbucks, in the library) Activity: what’s happening in the situation (touring a museum, reading a book) Time: current time, duration of event, temporal ordering Secondary Categories Indexed by primary category Phone number, address, social network, etc.. E.g. identity -> email address, phone number, etc.. Context-Aware Applications “A system is context-aware if it uses context to provide relevant information and/or services to the user, where relevancy depends on the user’s task.” Context-Aware Features 1. Presentation of information and services Tour guide, Active Badges 2. Automatic execution of services Smart homes (turn off lights, adjust temperature) 3. Tagging of context to information for later retrieval Digital camera meta-data (time, location) Context Toolkit [Salber et al, 1999] Active Badges Implications of Representable Context Context is: ◦ Form of information that can be encoded ◦ Delineable: in advance define what contexts are relevant for the application ◦ Stable: determination of relevance of potential context in an activity can be made once, reused ◦ Separable from activity  Example Application Structures in Information Spaces User places items in a two dimensional space, interact directly with data System suggests relationships, user may work off those suggestions Suggested by Application  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Understanding Ethical and Social Issues Related to Systems Ethics Principles of right and wrong that individuals, acting as free moral agents, use to make choices to guide their behavior Information systems and ethics Information systems raise new ethical questions because they create opportunities for: Intense social change, threatening existing distributions of power, money, rights, and obligations New kinds of crime  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Understanding Ethical and Social Issues Related to Systems A model for thinking about ethical, social, and political issues Society as a calm pond IT as a rock dropped in pond, creating ripples of new situations not covered by old rules Social and political institutions cannot respond overnight to these ripples — it may take years to develop etiquette, expectations, laws Requires understanding of ethics to make choices in legally gray areas  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Understanding Ethical and Social Issues Related to Systems Five moral dimensions of information age Major issues raised by information systems include: Information rights and obligations Property rights and obligations Accountability and control System quality Quality of life  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Understanding Ethical and Social Issues Related to Systems Four key technology trends that raise ethical issues Computing power doubles every 18 months Increased reliance on, and vulnerability to, computer systems Data storage costs rapidly declining Multiplying databases on individuals Data analysis advances Greater ability to find detailed personal information on individuals Profiling and nonobvious relationship awareness (NORA) Networking advances and the Internet Enables moving and accessing large quantities of personal data  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Ethics in an Information Society Basic concepts form the underpinning of an ethical analysis of information systems and those who manage them Responsibility: Accepting the potential costs, duties, and obligations for decisions Accountability: Mechanisms for identifying responsible parties Liability: Permits individuals (and firms) to recover damages done to them Due process: Laws are well known and understood, with an ability to appeal to higher authorities  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Ethics in an Information Society Ethical analysis: A five-step process 1. Identify and clearly describe the facts 2. Define the conflict or dilemma and identify the higher- order values involved 3. Identify the stakeholders 4. Identify the options that you can reasonably take 5. Identify the potential consequences of your options  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems Ethics in an Information Society Professional codes of conduct Promulgated by associations of professionals E.g. AMA, ABA, AITP, ACM Promises by professions to regulate themselves in the general interest of society Real-world ethical dilemmas One set of interests pitted against another E.g., Right of company to maximize productivity of workers vs. workers right to use Internet for short personal tasks  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems The Moral Dimensions of Information Systems Information rights and obligations Privacy Claim of individuals to be left alone, free from surveillance or interference from other individuals, organizations, or the state. Ability to control information about yourself In U.S., privacy protected by: First Amendment (freedom of speech) Fourth Amendment (unreasonable search and seizure) Additional federal statues Privacy Act of 1974  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems The Moral Dimensions of Information Systems Internet Challenges to Privacy: Cookies Tiny files downloaded by Web site to visitor’s hard drive Identify visitor’s browser and track visits to site Allow Web sites to develop profiles on visitors Web bugs Tiny graphics embedded in e-mail messages and Web pages Designed to monitor who is reading a message and transmitting that information to another computer on the Internet Spyware Surreptitiously installed on user’s computer May transmit user’s keystrokes or display unwanted ads  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems The Moral Dimensions of Information Systems Technical solutions The Platform for Privacy Preferences (P3P) Allows Web sites to communicate privacy policies to visitor’s Web browser – user User specifies privacy levels desired in browser settings E.g., “medium” level accepts cookies from first-party host sites that have opt-in or opt-out policies but rejects third- party cookies that use personally identifiable information without an opt-in policy.  The Moral Dimensions of Information Systems System Quality: Data Quality and System Errors What is an acceptable, technologically feasible level of system quality? Flawless software is economically unfeasible Three principal sources of poor system performance: Software bugs, errors Hardware or facility failures Poor input data quality (most common source of business system failure)  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems The Moral Dimensions of Information Systems Quality of Life: Negative social consequences of systems Balancing power: Although computing power is decentralizing, key decision-making power remains centralized Rapidity of change: Businesses may not have enough time to respond to global competition Maintaining boundaries: Computing and Internet use lengthens the work-day, infringes on family, personal time Dependence and vulnerability: Public and private organizations ever more dependent on computer systems  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems The Moral Dimensions of Information Systems Computer crime and abuse Computer crime: Commission of illegal acts through use of compute or against a computer system – computer may be object or instrument of crime Computer abuse: Unethical acts, not illegal Spam: High costs for businesses in dealing with spam Employment: Reengineering work resulting in lost jobs  Management Information Systems Chapter 4 Ethical and Social Issues in Information Systems The Moral Dimensions of Information Systems Health risks: Repetitive stress injury (RSI) Largest source is computer keyboards Carpal Tunnel Syndrome (CTS) Computer vision syndrome (CVS) Technostress Role of radiation, screen emissions, low-level electromagnetic fields Printing image made from small dots ◦ allows any character set or graphic to be printed, critical features: ◦ resolution ◦ size and spacing of the dots ◦ measured in dots per inch (dpi) ◦ speed ◦ usually measured in pages per minute ◦ cost!! Types of dot-based printers dot-matrix printers ◦ use inked ribbon (like a typewriter ◦ line of pins that can strike the ribbon, dotting the paper. ◦ typical resolution 80-120 dpi ink-jet and bubble-jet printers ◦ tiny blobs of ink sent from print head to paper ◦ typically 300 dpi or better. laser printer ◦ like photocopier: dots of electrostatic charge deposited on drum, which picks up toner (black powder form of ink) rolled onto paper which is then fixed with heat ◦ typically 600 dpi or better. Printing in the workplace shop tills ◦ dot matrix ◦ same print head used for several paper rolls ◦ may also print cheques thermal printers ◦ special heat-sensitive paper ◦ paper heated by pins makes a dot ◦ poor quality, but simple & low maintenance ◦ used in some fax machines Fonts Font – the particular style of text Courier font Helvetica font Palatino font Times Roman font §´ (special symbol) Size of a font measured in points (1 pt about 1/72”) (vaguely) related to its height This is ten point Helvetica This is twelve point This is fourteen point This is eighteen point and this is twenty-four point Fonts (ctd) Pitch ◦ fixed-pitch – every character has the same width e.g. Courier ◦ variable-pitched – some characters wider e.g. Times Roman – compare the ‘i’ and the “m” Serif or Sans-serif ◦ sans-serif – square-ended strokes e.g. Helvetica ◦ serif – with splayed ends (such as) e.g. Times Roman or Palatino Readability of text lowercase easy to read shape of words ◦ UPPERCASE better for individual letters and non-words ◦ e.g. flight numbers: BA793 vs. ba793 serif fonts helps your eye on long lines of printed text ◦ but sans serif often better on screen ◦ Page Description Languages Pages very complex ◦ different fonts, bitmaps, lines, digitised photos, etc. Can convert it all into a bitmap and send to the printer … but often huge ! Alternatively Use a page description language ◦ sends a description of the page can be sent, ◦ instructions for curves, lines, text in different styles, etc. ◦ like a programming language for printing! PostScript is the most common Screen and page WYSIWYG ◦ what you see is what you get ◦ aim of word processing, etc. but … ◦ screen: 72 dpi, landscape image ◦ print: 600+ dpi, portrait can try to make them similar but never quite the same so … need different designs, graphics etc, for screen and print Scanners Take paper and convert it into a bitmap Two sorts of scanner ◦ flat-bed: paper placed on a glass plate, whole page converted into bitmap ◦ hand-held: scanner passed over paper, digitising strip typically 3-4” wide Shines light at paper and note intensity of reflection ◦ colour or greyscale Typical resolutions from 600–2400 dpi Scanners (ctd) Used in ◦ desktop publishing for incorporating photographs and other images ◦ document storage and retrieval systems, doing away with paper storage + special scanners for slides and photographic negatives Optical character recognition OCR converts bitmap back into text different fonts ◦ create problems for simple “template matching” algorithms ◦ more complex systems segment text, decompose it into lines and arcs, and decipher characters that way page format ◦ columns, pictures, headers and footers memory SHORT TERM AND LONG TERM SPEED, CAPACITY, COMPRESSION FORMATS, ACCESS Short-term Memory - RAM Random access memory (RAM) on silicon chips ◦ 100 nano-second access time ◦ usually volatile (lose information if power turned off) ◦ data transferred at around 100 Mbytes/sec ◦ Some non-volatile RAM used to store basic set-up information Typical desktop computers: 64 to 256 Mbytes RAM Long-term Memory - disks magnetic disks floppy disks store around 1.4 Mbytes ◦ hard disks typically 40 Gbytes to 100s of Gbytes ◦ access time ~10ms, transfer rate 100kbytes/s optical disks use lasers to read and sometimes write ◦ more robust that magnetic media ◦ CD-ROM ◦ - same technology as home audio, ~ 600 Gbytes DVD - for AV applications, or very large files ◦ Blurring boundaries PDAs ◦ often use RAM for their main memory Flash-Memory ◦ used in PDAs, cameras etc. ◦ silicon based but persistent ◦ plug-in USB devices for data transfer speed and capacity what do the numbers mean? some sizes (all uncompressed) … ◦ this book, text only ~ 320,000 words, 2Mb ◦ the Bible ~ 4.5 Mbytes ◦ scanned page ~ 128 Mbytes ◦ (11x8 inches, 1200 dpi, 8bit greyscale) ◦ digital photo ~ 10 Mbytes ◦ (2–4 mega pixels, 24 bit colour) ◦ video ~ 10 Mbytes per second ◦ (512x512, 12 bit colour, 25 frames per sec) virtual memory Problem: ◦ running lots of programs + each program large ◦ not enough RAM Solution - Virtual memory : ◦ store some programs temporarily on disk ◦ makes RAM appear bigger But … swopping ◦ program on disk needs to run again ◦ copied from disk to RAM ◦ slows t h i n g s d o w n Compression reduce amount of storage required lossless ◦ recover exact text or image – e.g. GIF, ZIP ◦ look for commonalities: ◦ text: AAAAAAAAAABBBBBCCCCCCCC 10A5B8C ◦ video: compare successive frames and store change lossy ◦ recover something like original – e.g. JPEG, MP3 ◦ exploit perception ◦ JPEG: lose rapid changes and some colour ◦ MP3: reduce accuracy of drowned out notes Storage formats - text ASCII - 7-bit binary code for to each letter and character UTF-8 - 8-bit encoding of 16 bit character set RTF (rich text format) - text plus formatting and layout information SGML (standardized generalised markup language) - documents regarded as structured objects XML (extended markup language) - simpler version of SGML for web applications Storage formats - media Images: ◦ many storage formats : (PostScript, GIFF, JPEG, TIFF, PICT, etc.) ◦ plus different compression techniques (to reduce their storage requirements) Audio/Video ◦ again lots of formats : (QuickTime, MPEG, WAV, etc.) ◦ compression even more important ◦ also ‘streaming’ formats for network delivery methods of access large information store ◦ long time to search => use index ◦ what you index -> what you can access simple index needs exact match forgiving systems: ◦ Xerox “do what I mean” (DWIM) ◦ SOUNDEX – McCloud ~ MacCleod access without structure … ◦ free text indexing (all the words in a document) ◦ needs lots of space!! processing and networks FINITE SPEED (BUT ALSO MOORE ’S LAW) LIMITS OF INTERACTION NETWORKED COMPUTING Finite processing speed Designers tend to assume fast processors, and make interfaces more and more complicated But problems occur, because processing cannot keep up with all the tasks it needs to do ◦ cursor overshooting because system has buffered keypresses ◦ icon wars - user clicks on icon, nothing happens, clicks on another, then system responds and windows fly everywhere Also problems if system is too fast - e.g. help screens may scroll through text much too rapidly to be read  Moore’s law computers get faster and faster! 1965 … Gordon Moore, co-founder of Intel, noticed a pattern ◦ processor speed doubles every 18 months ◦ PC … 1987: 1.5 Mhz, 2002: 1.5 GHz ◦ similar pattern for memory but doubles every 12 months!! ◦ hard disk … 1991: 20Mbyte : 2002: 30 Gbyte ◦ baby born today record all sound and vision ◦ by 70 all life’s memories stored in a grain of dust! ◦ /e3/online/moores-law/ the myth of the infinitely fast machine implicit assumption … no delays an infinitely fast machine what is good design for real machines? good example … the telephone : ◦ type keys too fast ◦ hear tones as numbers sent down the line ◦ actually an accident of implementation ◦ emulate in deisgn Limitations on interactive performance Computation bound ◦ Computation takes ages, causing frustration for the user Storage channel bound ◦ Bottleneck in transference of data from disk to memory Graphics bound ◦ Common bottleneck: updating displays requires a lot of effort - sometimes helped by adding a graphics co-processor optimised to take on the burden Network capacity ◦ Many computers networked - shared resources and files, access to printers etc. - but interactive performance can be reduced by slow network speed Networked computing Networks allow access to … ◦ large memory and processing ◦ other people (groupware, email) ◦ shared resources – esp. the web Issues ◦ network delays – slow feedback ◦ conflicts - many people update data ◦ unpredictability The internet history … ◦ 1969: DARPANET US DoD, 4 sites ◦ 1971: 23; 1984: 1000; 1989: 10000 common language (protocols): ◦ TCP – Transmission Control protocol ◦ lower level, packets (like letters) between machines ◦ IP – Internet Protocol ◦ reliable channel (like phone call) between programs on machines ◦ email, HTTP, all build on top of these