Glossary

abacus:

an ancient counting device that probably originated in Babylon around 2,400 B.C.E.

acuity:

sharpness or keenness, especially when used to describe vision

address bus:

a collection of electrical signals used to transmit the address of a memory location or input/output port in a computer

aerodynamics:

the science and engineering of systems that are capable of flight

agents:

systems (software programs and/or computing machines) that can act on behalf of another, or on behalf of a human

aggregate:

a numerical summation of multiple individual scores

ailerons:

control surfaces on the trailing edges of the wings of an aircraft— used to manage roll control

ALGOL:

a language developed by the ALGOL committee for scientific applications—acronym for ALGOrithmic Language

algorithm:

a rule or procedure used to solve a mathematical problem—most often described as a sequence of steps

all-points-addressable mode:

a technique for organizing graphics devices where all points (pixels) on the screen are individually accessible to a running program

alpha beta pruning:

a technique that under certain conditions offers an optimal way to search through data structures called "trees"

alphanumeric:

a character set which is the union of the set of alphabetic characters and the set of single digit numbers

ambient:

pertaining to the surrounding atmosphere or environment

ambiguity:

the quality of doubtfulness or uncertainty; often subject to multiple interpretations

amortized:

phasing out something in until it is gradually extinguished, like a mortgage loan

amplitude:

the size or magnitude of an electrical signal

analog:

a quantity (often an electrical signal) that is continuous in time and amplitude

analogous:

a relationship of logical similarity between two or more objects

analytic simulation:

modeling of systems by using mathematical equations (often differential equations) and programming a computer with them to simulate the behavior of the real system

Analytical Engine:

Charles Babbage's vision of a programmable mechanical computer

animatronics:

the animation (movement) of something by the use of electronic motors, drives, and controls

anthropomorphic:

having human form, or generally resembling human appearance

anti-aliasing:

introducing shades of gray or other intermediate shades around an image to make the edge appear to be smoother

applet:

a program component that requires extra support at run time from a browser or run-time environment in order to execute

approximation:

an estimate

arc tangent:

the circular trigonometric function that is the inverse of the tangent function; values range from -Π/2 to Π/2

artificial intelligence (AI):

a branch of computer science dealing with creating computer hardware and software to mimic the way people think and perform practical tasks

ASCII:

an acronym that stands for American Standard Code for Information Interchange; assigns a unique 8-bit binary number to every letter of the alphabet, the digits (0 to 9), and most keyboard symbols

assembler:

a program that translates human-readable assembly language programs to machine-readable instructions

assembly language:

the natural language of a central processing unit (CPU); often classed as a low-level language

asynchronous:

events that have no systematic relationship to one another in time

attenuation:

the reduction in magnitude (size or amplitude) of a signal that makes a signal weaker

authentication:

the act of ensuring that an object or entity is what it is intended to be

automata theory:

the analytical (mathematical) treatment and study of automated systems

automaton:

an object or being that has a behavior that can be modeled or explained completely by using automata theory

autonomous:

self governing, or being able to exist independently

autonomy:

the capability of acting in a self-governing manner; being able to exist independently or with some degree of independence

axioms:

statements that are taken to be true, the foundation of a theory

Bakelite:

an insulating material used in synthetic goods, including plastics and resins

ballistics:

the science and engineering of the motion of projectiles of various types, including bullets, bombs, and rockets

bandwidth:

a measure of the frequency component of a signal or the capacity of a communication channel to carry signals

bar code:

a graphical number representation system where alphanumeric characters are represented by vertical black and white lines of varying width

base-2:

a number system in which each place represents a power of 2 larger than the place to its right (binary)

base-8:

a number system in which each place represents a power of 8 larger than the place to its right (octal)

base-10:

a number system in which each place represents a power of 10 larger than the place to its right (decimal)

base-16:

a number system in which each place represents a power of 16 larger than the place to its right (hexadecimal)

batch processing:

an approach to computer utilization that queues noninteractive programs and runs them one after another

Bayesian networks:

structures that describe systems in which there is a degree of uncertainty; used in automated decision making

Bernoulli numbers:

the sums of powers of consecutive integers; named after Swiss mathematician Jacques Bernoulli (1654-1705)

binary:

existing in only two states, such as "on" or "off," "one" or "zero"

binary code:

a representation of information that permits only two states, such as "on" or "off," "one" or "zero"

binary coded decimal (BCD):

an ANSI/ISO standard encoding of the digits 0 to 9 using 4 binary bits; the encoding only uses 10 of the available 16 4-bit combinations

binary digit:

a single bit, 1 or 0

binary number system:

a number system in which each place represents a power of 2 larger than the place on its right (base-2)

binary system:

a machine or abstraction that uses binary codes

binomial theorem:

a theorem giving the procedure by which a binomial expression may be raised to any power without using successive multiplications

bit:

a single binary digit, 1 or 0—a contraction of Binary digIT; the smallest unit for storing data in a computer

bit mapped display:

a computer display that uses a table of binary bits in memory to represent the image that is projected onto the screen

bit maps:

images comprised of bit descriptions of the image, in black and white or color, such that the colors can be represented by the two values of a binary bit

bit rate:

the rate at which binary bits can be processed or transferred per unit time, in a system (often a computer communications system)

bit serial mode:

a method of transferring binary bits one after another in a sequence or serial stream

bitstream:

a serialized collection of bits; usually used in transfer of bits from one system to another

Boolean algebra:

a system developed by George Boole that deals with the theorems of undefined symbols and axioms concerning those symbols

Boolean logic:

a system, developed by George Boole, which treats abstract objects (such as sets or classes) as algebraic quantities; Boole applied his mathematical system to the study of classical logic

Boolean operators:

fundamental logical operations (for example "and" and "or") expressed in a mathematical form

broadband access:

a term given to denote high bandwidth services

browsers:

programs that permits a user to view and navigate through documents, most often hypertext documents

bugs:

errors in program source code

bus:

a group of related signals that form an interconnecting pathway between two or more electronic devices

bus topology:

a particular arrangement of buses that constitutes a designed set of pathways for information transfer within a computer

byte:

a group of eight binary digits; represents a single character of text

C:

a programming language developed for the UNIX operating system; it is designed to run on most machines and with most operating systems

cache:

a small sample of a larger set of objects, stored in a way that makes them accessible

calculus:

a method of dealing mathematically with variables that may be changing continuously with respect to each other

Callback modems:

security techniques that collect telephone numbers from authorized users on calls and then dial the users to establish the connections

capacitates:

fundamental electrical components used for storing electrical charges

capacitor:

a fundamental electrical component used for storing an electrical charge

carpal tunnel syndrome:

a repetitive stress injury that can lead to pain, numbness, tingling, and loss of muscle control in the hands and wrists

cartography:

map making

cathode ray tube (CRT):

a glass enclosure that projects images by directing a beam of electrons onto the back of a screen

cellular automata:

a collection or array of objects that are programmed identically to interact with one another

cellular neural networks (CNN):

a neural network topology that uses multidimensional array structures comprised of cells that work together in localized groups

central processing unit (CPU):

the part of a computer that performs computations and controls and coordinates other parts of the computer

certificate:

a unique electronic document that is used to assist authentication

chaos theory:

a branch of mathematics dealing with differential equations having solutions which are very sensitive to initial conditions

checksum:

a number that is derived from adding together parts of an electronic message before it is dispatched; it can be used at the receiver to check against message corruption

chromatic dispersion:

the natural distortion of pulses of light as they move through an optical network; it results in data corruption

cipher:

a code or encryption method

client:

a program or computer often managed by a human user, that makes requests to another computer for information

client/server technology:

computer systems that are structured using clients (usually human driven computers) to access information stored (often remotely) on other computers known as servers

coaxial cable:

a cable with an inner conducting core, a dielectric material and an outer sheath that is designed for high frequency signal transmission

cognitive:

pertaining to the concepts of knowing or perceiving

collocation:

the act of placing elements or objects in a specific order

commodity:

raw material or service marketed prior to being used

compiled:

a program that is translated from human-readable code to binary code that a central processing unit (CPU) can understand

compiled executable code:

the binary code that a central processing unit (CPU) can understand; the product of the compilation process

compilers:

programs that translate human-readable high-level computer languages to machine-readable code

computer-aided design (CAD):

the use of computers to replace traditional drawing instruments and tools for engineering or architectural design

computer-assisted tomography:

the use of computers in assisting with the management of X-ray images

computer peripheral:

a device that is connected to a computer to support its operation; for example, a keyboard or a disk drive unit

concatenates:

the joining together of two elements or objects; for example, words are formed by concatenating letters

concentric circles:

circles that have coincident centers

conceptualization:

a creative process that is directed at envisaging a structure or collection of relationships within components of a complex system

concurrency control:

the management and coordination of several actions that occur simultaneously; for example, several computer programs running at once

concurrent:

pertaining to simultaneous activities, for example simultaneous execution of many computer programs

configuration files:

special disk files containing information that can be used to tell running programs about system settings

cookie:

a small text file that a web site can place on a computer's hard drive to collect information about a user's browsing activities or to activate an online shopping cart to keep track of purchases

copyrights:

the legal rules and regulations concerning the copying and redistribution of documents

cosine:

a trigonometric function of an angle, defined as the ratio of the length of the adjacent side of a right-angled triangle divided by the length of its hypotenuse

counterfeiting:

the act of knowingly producing non-genuine objects, especially in relation to currency

crawls:

severe weather warnings that are broadcast on the bottom of TV screens

cross-platform:

pertaining to a program that can run on many different computer types (often called hardware platforms)

CRT:

the acronym for cathode ray tube, which is a glass enclosure that projects images by directing a beam of electrons onto the back of a screen

cryptanalysis:

the act of attempting to discover the algorithm used to encrypt a message

cryptanalyst:

a person or agent who attempts to discover the algorithm used to encrypt a message

cryptography:

the science of understanding codes and ciphers and their application

cryptosystem:

a system or mechanism that is used to automate the processes of encryption and decryption

cuneiform:

in the shape of a wedge

cybercafe:

a shop, cafe, or meeting place where users can rent a computer for a short time to access the Internet

cybernetics:

a unified approach to understanding the behavior of machines and animals developed by Norbert Wiener (1894-1964)

cycloids:

pertaining to circles, in either a static way or in a way that involves movement

dark fiber:

a fiber optic network that exists but is not actively in service, hence the darkness

data mining:

a technique of automatically obtaining information from databases that is normally hidden or not obvious

data partitioning:

a technique applied to databases (but not restricted to them) which organizes data objects into related groups

data reduction technique:

an approach to simplifying data, e.g. summarization

data warehousing:

to implement an informational database used to store shared data

de facto:

as is

de jure:

strictly according to the law

debug:

the act of trying to trace, identify, and then remove errors in program source code

decimal system:

a number system in which each place represents a power of 10 larger than the place to its right (base-10)

decision trees:

classifiers in which a sequence of tests are made to decide the class label to assign to an unknown data item; the sequence of tests can be visualized as having a tree structure

deformations:

mechanical systems where a structure is physically misshapen, e.g., dented

degrade:

to reduce quality or performance of a system

delimiters:

special symbols that mark the beginnings and/or endings of other groups of symbols (for example to mark out comments in program source code)

demographics:

the study of the statistical data pertaining to a population

densities:

measures of the density of a material; defined as the mass of a sample of material, divided by its volume

deregulation:

the lowering of restrictions, rules, or regulations pertaining to an activity or operation (often commercial)

die:

the silicon chip that is the heart of integrated circuit fabrication; the die is encased in a ceramic or plastic package to make the completed integrated circuit (IC)

dielectric:

a material that exhibits insulating properties, as opposed to conducting properties

Difference Engine:

a mechanical calculator designed by Charles Babbage that automated the production of mathematical tables by using the method of differences

differential analyzer:

a computer constructed in the early 1930s by Vannevar Bush at Massachusetts Institute of Technology (MIT); it solved differential equations by mechanical integration

digital:

a quantity that can exist only at distinct levels, not having values in between these levels (for example, binary)

digital certificates:

certificates used in authentication that contain encrypted digital identification information

digital divide:

imaginary line separating those who can access digital information from those who cannot

digital library:

distributed access to collections of digital information

digital signature:

identifier used to authenticate the sender of an electronic message or the signer of an electronic document

digital subscriber line (DSL):

a technology that permits high-speed voice and data communications over public telephone networks; it requires the use of a DSL modem

digital subscriber loop (DSL):

the enabling of high-speed digital data transfer over standard telephone cables and systems in conjunction with normal telephone speech data

digital watermarks:

special data structures permanently embedded into a program or other file type, which contain information about the author and the program

digitizes:

converts analog information into a digital form for processing by a computer

diode:

a semiconductor device that forces current flow in a conductor to be in one direction only, also known as a rectifier

diode tube:

an obsolete form of diode that was made of metal elements in a sealed and evacuated glass tube

direction buttons:

buttons on a program with a graphical user interface that provide a way of navigating through information or documents

discrete:

composed of distinct elements

disintermediation:

a change in business practice whereby consumers elect to cut out intermediary agencies and deal directly with a provider or vendor

distance learning:

the form of education where the instructor and students are separated by either location or time (or both), usually mediated by some electronic communication mechanism

distributed denial of service (DDoS):

an attack in which large numbers of messages are directed to send network traffic to a target computer, overloading it or its network connection; typically, the attacking computers have been subverted

distributed systems:

computer systems comprised of many individual computers that are interconnected and act in concert to complete operations

documentation:

literature in a human-readable form that is referred to in support of using a computer or computer system

domain:

a region in which a particular element or object exists or has influence; (math) the inputs to a function or relation

doping:

a step used in the production of semiconductor materials where charged particles are embedded into the device so as to tailor its operational characteristics

dot.com:

a common term used to describe an Internet-based commercial company or organization

dragged:

to have been moved by the application of an external pulling force; quite often occurring in graphical user interfaces when objects are moved with a mouse

DRAM:

the acronym for Dynamic Random Access Memory; high density, low cost and low speed memory devices used in most computer systems

driver:

a special program that manages the sequential execution of several other programs; a part of an operating system that handles input/output devices

drop-down menu:

a menu on a program with a graphical user interface that produces a vertical list of items when activated

dumb terminal:

a keyboard and screen connected to a distant computer without any processing capability

duplex:

simultaneous two-directional communication over a single communication channel

dynamic:

changing; possessing volatility

dynamic links:

logical connections between two objects that can be modified if the objects themselves move or change state

e-books:

short for electronic books; books available for downloading onto an e-book reader

EBCDIC:

the acronym for Extended Binary Coded Decimal Interchange Code, which assigns a unique 8-bit binary number to every letter of the alphabet, the digits (0-9), and most keyboard symbols

egress:

to move out of an object, system, or environment

electromagnetic:

a piece of metal that becomes magnetic only when electricity is applied to it; in general, the more electricity applied to metal, the stronger its magnetism

electromagnetic relays:

switches that have a high current carrying capacity, which are opened and closed by an electromagnet

electromagnetic spectrum:

a range of frequencies over which electromagnetic radiation can be generated, transmitted, and received

embedded computers:

computers that do not have human user orientated I/O devices; they are directly contained within other machines

embedded systems:

another term for "embedded computers"; computers that do not have human user orientated input/output devices; they are directly contained within other machines

emoticons:

symbols or key combinations used in electronic correspondence to convey emotions

enciphered:

encrypted or encoded; a mathematical process that disguises the content of messages transmitted

encryption:

also known as encoding; a mathematical process that disguises the content of messages transmitted

end-effector:

the end piece of a robotic arm that can receive various types of grippers and tools

end users:

computer users

enterprise information system:

a system of client and server computers that can be used to manage all of the tasks required to manage and run a large organization

entropy:

a measure of the state of disorder or randomness in a system

ephemeris:

a record showing positions of astronomical objects and artificial satellites in a time-ordered sequence

ergonomic:

being of suitable geometry and structure to permit effective or optimal human user interaction with machines

esoteric:

relating to a specialized field of endeavor that is characterized by its restricted size

ether:

a highly volatile liquid solvent; also, the far regions of outer space

ethernets:

a networking technology for mini and microcomputer systems consisting of network interface cards and interconnecting coaxial cables; invented in the 1970s by Xerox Corporation

Euclidean geometry:

the study of points, lines, angles, polygons, and curves confined to a plane

expert system:

a computer system that uses a collection of rules to exhibit behavior which mimics the behavior of a human expert in some area

fiber optics:

transmission technology using long, thin strands of glass fiber; internal reflections in the fiber assure that light entering one end is transmitted to the other end with only small losses in intensity; used widely in transmitting digital information

field searching:

a strategy in which a search is limited to a particular field; in a search engine, a search may be limited to a particular domain name or date, narrowing the scope of searchable items and helping to eliminate the chance of retrieving irrelevant data

file transfer protocol (FTP):

a communications protocol used to transfer files

filter queries:

queries used to select subsets from a data collection, e.g., all documents with a creation date later than 01/01/2000

firewall:

a special purpose network computer or software that is used to ensure that no access is permitted to a sub-network unless authenticated and authorized

firing tables:

precalculated tables that can give an artillery gunner the correct allowances for wind conditions and distance by dictating the elevation and deflection of a gun

floating point operations:

numerical operations involving real numbers where in achieving a result, the number of digits to the left or right of the decimal point can change

flowcharts:

techniques for graphically describing the sequencing and structure of program source code

fluid dynamics:

the science and engineering of the motion of gases and liquids

Freedom of Information Act (FOIA):

permits individuals to gain access to records and documents that are in the possession of the government

freon:

hydrocarbon-based gases used as refrigerants and as pressurants in aerosols

frequency bands:

ranges of signal frequencies that are of particular interest in a given application

frequency modulation:

a technique whereby a signal is transformed so that it is represented by another signal with a frequency that varies in a way related to the original signal

full-text indexing:

a search engine feature in which every word in a document, significant or insignificant, is indexed and retrievable through a search

fuzzy logic:

models human reasoning by permitting elements to have partial membership to a set; derived from fuzzy set theory

gallium arsenide:

a chemical used in the production of semiconductor devices; chemical symbol GaAs

gates:

fundamental building blocks of digital and computer-based electric circuits that perform logical operations; for example logical AND, logical OR

Gaussian classifiers:

classifiers constructed on the assumption that the feature values of data will follow a Gaussian distribution

gbps:

acronym for gigabits per second; a binary data transfer rate that corresponds to a thousand million (billion, or 109) bits per second

geometric:

relating to the principles of geometry, a branch of mathematics related to the properties and relationships of points, lines, angles, surfaces, planes, and solids

germanium:

a chemical often used as a high performance semiconductor material; chemical symbol Ge

GIF animation:

a technique using Graphic Interchange Format where many images are overlaid on one another and cycled through a sequence to produce an animation

GIF image:

the acronym for Graphic Interchange Format where a static image is represented by binary bits in a data file

gigabit networking:

the construction and use of a computer network that is capable of transferring information at rates in the gigahertz range

gigabytes:

units of measure equivalent to a thousand million (billion, or 109) bytes

gigahertz (GHz):

a unit or measure of frequency, equivalent to a thousand million (billion, or 109) hertz, or cycles per second

Global Positioning System (GPS):

a method of locating a point on the Earth's surface that uses received signals transmitted from satellites to calculate position accurately

granularity:

a description of the level of precision that can be achieved in making measurements of a quantity; for example coarse granularity means inexpensive but imprecise measurements

graphical user interface (GUI):

an interface that allows computers to be operated through pictures (icons) and mouse-clicks, rather than through text and typing

groupware:

a software technology common in client/server systems whereby many users can access and process data at the same time

gyros:

a contraction of gyroscopes; a mechanical device that uses one or more spinning discs which resist changes to their position in space

half tones:

black and white dots of certain sizes, which provide a perception of shades of gray

ham radio:

a legal (or licensed) amateur radio

haptic:

pertaining to the sense of touch

Harvard Cyclotron:

a specialized machine (cyclotron) developed in 1948 at Harvard University; it is used to carry out experiments in sub-atomic physics and medicine

head-mounted displays (HMD):

helmets worn by a virtual reality (VR) participant that include speakers and screens for each eye, which display three- dimensional images

hertz (Hz):

a unit of measurement of frequency, equal to one cycle per second; named in honor of German physicist Heinrich Hertz (1857-1894)

heuristic:

a procedure that serves to guide investigation but that has not been proven

hexadecimal:

a number system in which each place represents a power of 16 larger than the place to its right (base-16)

high-bandwidth:

a communication channel that permits many signals of differing frequencies to be transmitted simultaneously

high precision/high recall:

a phenomenon that occurs during a search when all the relevant documents are retrieved with no unwanted ones

high precision/low recall:

a phenomenon that occurs when a search yields a small set of hits; although each one may be highly relevant to the search topic, some relevant documents are missed

high-speed data links:

digital communications systems that permit digital data to be reliably transferred at high speed

hoaxes:

false claims or assertions, sometimes made unlawfully in order to extort money

holistic:

looking at the entire system, rather than just its parts

hydraulic:

motion being powered by a pressurized liquid (such as water or oil), supplied through tubes or pipes

hydrologic:

relating to water

hyperlinks:

connections between electronic documents that permit automatic browsing transfer at the point of the link

Hypertext Markup Language (HTML):

an encoding scheme for text data that uses special tags in the text to signify properties to the viewing program (browser) like links to other documents or document parts

Hypertext Transfer Protocol (HTTP):

a simple connectionless communications protocol developed for the electronic transfer (serving) of HTML documents

I/O:

the acronym for input/output; used to describe devices that can accept input data to a computer and to other devices that can produce output

I/O devices:

devices that can accept "input" data to a computer and to other devices that can produce "output"

icon:

a small image that is used to signify a program or operation to a user

illiquid:

lacking in liquid assets; or something that is not easily transferable into currency

ImmersaDesks:

large 4 x 5 foot screens that allow for stereoscopic visualization; the 3-D computer graphics create the illusion of a virtual environment

ImmersaWalls:

large-scale, flat screen visualization environments that include passive and active multi-projector displays of 3-D images

immersive:

involved in something totally

in-band:

pertaining to elements or objects that are within the limits of a certain local area network (LAN)

inference:

a suggestion or implication of something based on other known related facts and conclusions

information theory:

a branch of mathematics and engineering that deals with the encoding, transmission, reception, and decoding of information

infrared (IR) waves:

radiation in a band of the electromagnetic spectrum within the infrared range

infrastructure:

the foundation or permanent installation necessary for a structure or system to operate

ingot:

a formed block of metal (often cast) used to facilitate bulk handling and transportation

ingress:

the act of entering a system or object

init method:

a special function in an object oriented program that is automatically called to initialize the elements of an object when it is created

input/output (I/O):

used to describe devices that can accept input data to a computer and to other devices that can produce output

intangible:

a concept to which it is difficult to apply any form of analysis; something which is not perceived by the sense of touch

integrated circuit:

a circuit with the transistors, resistors, and other circuit elements etched into the surface of a single chip of semiconducting material, usually silicon

integrated modem:

a modem device that is built into a computer, rather than being attached as a separate peripheral

intellectual property:

the acknowledgement that an individual's creativity and innovation can be owned in the same way as physical property

interconnectivity:

the ability of more than one physical computer to operate with one or more other physical computers; interconnectivity is usually accomplished by means of network wiring, cable, or telephone lines

interface:

a boundary or border between two or more objects or systems; also a point of access

Internet Protocol (IP):

a method of organizing information transfer between computers; the IP was specifically designed to offer low-level support to Transmission Control Protocol (TCP)

Internet Service Provider (ISP):

a commercial enterprise which offers paying subscribers access to the Internet (usually via modem) for a fee

interpolation:

estimating data values between known points but the values in between are not and are therefore estimated

intranet:

an interconnected network of computers that operates like the Internet, but is restricted in size to a company or organization

ionosphere:

a region of the upper atmosphere (above about 60,000 meters or 196,850 feet) where the air molecules are affected by the sun's radiation and influence electromagnetic wave propagation

isosceles triangle:

a triangle that has two sides of equivalent length (and therefore two angles of the same size)

iterative:

a procedure that involves repetitive operations before being completed

Jacquard's Loom:

a weaving loom, developed by Joseph-Marie Jacquard (1752-1834), controlled by punched cards; identified as one of the earliest examples of programming automation

Java applets:

applets written in the Java programming language and executed with the support of a Java Virtual Machine (JVM) or a Java enabled browser

joysticks:

the main controlling levers of small aircraft; models of these can be connected to computers to facilitate playing interactive games

JPEG (Joint Photographic Experts Group):

organization that developed a standard for encoding image data in a compressed format to save space

k-nearest neighbors:

a classifier that assigns a class label for an unknown data item by looking at the class labels of the nearest items in the training data

Kbps:

a measure of digital data transfer per unit time—one thousand (kilo, K) bits per second

keywords:

words that are significant in some context or topic (often used in searching)

kilohertz (kHz):

a unit or measure of frequency, equivalent to a thousand (or 103) hertz, or cycles per second

kinematics:

a branch of physics and mechanical engineering that involves the study of moving bodies and particles

kinetics:

a branch of physics or chemistry concerned with the rate of change in chemical or physical systems

labeled data:

a data item whose class assignment is known independent of the classifier being constructed

lambda calculus:

important in the development of programming languages, a specialized logic using substitutions that was developed by Alonzo Church (1903-1995)

LEDs:

the acronym for Light Emitting Diode; a diode that emits light when passing a current and used as an indicating lamp

lexical analyzer:

a portion of a compiler that is responsible for checking the program source code produced by a programmer for proper words and symbols

Library of Congress Classification:

the scheme by which the Library of Congress organizes classes of books and documents

light emitting diode (LED):

a discrete electronic component that emits visible light when permitting current to flow in a certain direction; often used as an indicating lamp

linear:

pertaining to a type of system that has a relationship between its outputs and its inputs that can be graphed as a straight line

Linux operating system:

an open source UNIX operating system that was originally created by Linus Torvalds in the early 1990s

liquid crystal display (LCD):

a type of crystal that changes its level of transparency when subjected to an electric current; used as an output device on a computer

local area network (LAN):

a high-speed computer network that is designed for users who are located near each other

logarithm:

the power to which a certain number called the base is to be raised to produce a particular number

logic:

a branch of philosophy and mathematics that uses provable rules to apply deductive reasoning

lossy:

a nonreversible way of compressing digital images; making images take up less space by permanently removing parts that cannot be easily seen anyway

low precision/high recall:

a phenomenon that occurs during a search when a large set of results are retrieved, including many relevant and irrelevant documents

lumens:

a unit of measure of light intensity

magnetic tape:

a way of storing programs and data from computers; tapes are generally slow and prone to deterioration over time but are inexpensive

mainframe:

large computer used by businesses and government agencies to process massive amounts of data; generally faster and more powerful than desktop computers but usually requiring specialized software

malicious code:

program instructions that are intended to carry out malicious or hostile actions; e.g., deleting a user's files

mammogram:

an X-ray image of the breast, used to detect signs of possible cancer

Manhattan Project:

the U.S. project designed to create the world's first atomic bomb

mass spectrometers:

instruments that can identify elemental particles in a sample by examining the frequencies of the particles that comprise the sample

mass spectrometry:

the process of identifying the compounds or elemental particles within a substance

megahertz (MHz):

a unit or measure of frequency, equivalent to a million (or 106) hertz, or cycles per second

memex:

a device that can be used to store personal information, notes, and records that permits managed access at high speed; a hypothetical creation of Vannevar Bush

menu label:

the text or icon on a menu item in a program with a graphical user interface

metadata:

data about data, such as the date and time created

meteorologists:

people who have studied the science of weather and weather forecasting

metropolitan area network (MAN):

a high-speed interconnected network of computers spanning entire cities

microampere:

a unit of measure of electrical current that is one-millionth (10-6) amperes

microchip:

a common term for a semiconductor integrated circuit device

microcomputer:

a computer that is small enough to be used and managed by one person alone; often called a personal computer

microprocessor:

the principle element in a computer; the component that understands how to carry out operations under the direction of the running program (CPU)

millisecond:

a time measurement indicating one-thousandth (or 10-3) of a second

milliwatt:

a power measurement indicating one-thousandth (or 10-3) of a watt

minicomputers:

computers midway in size between a desktop computer and a mainframe computer; most modern desktops are much more powerful than the older minicomputers

minimax algorithm:

an approach to developing an optimal solution to a game or contest where two opposing systems are aiming at mutually exclusive goals

Minitel:

network used in France that preceded the Internet, connecting most French homes, businesses, cultural organizations, and government offices

mnemonic:

a device or process that aids one's memory

modalities:

classifications of the truth of a logical proposition or statement, or characteristics of an object or entity

modem:

the contraction of MOdulator DEModulator; a device which converts digital signals into signals suitable for transmission over analog channels, like telephone lines

modulation:

a technique whereby signals are translated to analog so that the resultant signal can be more easily transmitted and received by other elements in a communication system

modules:

a generic term that is applied to small elements or components that can be used in combination to build an operational system

molecular modeling:

a technique that uses high performance computer graphics to represent the structure of chemical compounds

motherboard:

the part of the computer that holds vital hardware, such as the processors, memory, expansion slots, and circuitry

MPEG (Motion Picture Coding Experts Group):

an encoding scheme for data files that contain motion pictures—it is lossy in the same way as JPEG (Joint Photographic Experts Group) encoding

multiplexes:

operations in ATM communications whereby data cells are blended into one continuous stream at the transmitter and then separated again at the receiver

multiplexor:

a complex device that acts as a multi-way switch for analog or digital signals

multitasking:

the ability of a computer system to execute more than one program at the same time; also known as multiprogramming

mylar:

a synthetic film, invented by the DuPont corporation, used in photographic printing and production processes, as well as disks and tapes

nanocomputing:

the science and engineering of building mechanical machines at the atomic level

nanometers:

one-thousand-millionth (one billionth, or 10-9) of a meter

nanosecond:

one-thousand-millionth (one billionth, or 10-9) of a second

nanotechnology:

the design and construction of machines at the atomic or molecular level

narrowband:

a general term in communication systems pertaining to a signal that has a small collection of differing frequency components (as opposed to broadband which has many frequency components)

National Computer Security Center (NCSC):

a branch of the National Security Agency responsible for evaluating secure computing systems; the Trusted Computer Systems Evaluation Criteria (TCSEC) were developed by the NCSC

Network Control Protocol (NCP):

a host-to-host protocol originally developed in the early 1970s to support the Internet, which was then a research project

network packet switching:

the act of routing and transferring packets (or small sections) of a carrier signal that conveys digital information

neural modeling:

the mathematical study and the construction of elements that mimic the behavior of the brain cell (neuron)

neural networks:

pattern recognition systems whose structure and operation are loosely inspired by analogy to neurons in the human brain

Newtonian view:

an approach to the study of mechanics that obeys the rules of Newtonian physics, as opposed to relativistic mechanics; named after Sir Isaac Newton (1642-1727)

nonlinear:

a system that has relationships between outputs and inputs which cannot be expressed in the form of a straight line

O-rings:

37-foot rubber circles (rings) that seal the joints between the space shuttle's rocket booster segments

OEM:

the acronym for Original Equipment Manufacturer; a manufacturer of computer components

offline:

the mode of operation of a computer that applies when it is completely disconnected from other computers and peripherals (like printers)

Open Systems Interconnections (OSI):

a communications standard developed by the International Organization for Standardization (ISO) to facilitate compatible network systems

operands:

when a computer is executing instructions in a program, the elements on which it performs the instructions are known as the operands

operating system:

a set of programs which control all the hardware of a computer and provide user and device input/output functions

optical character recognition:

the science and engineering of creating programs that can recognize and interpret printed characters

optical computing:

a proposed computing technology which would operate on particles of light, rather than electric currents

optophone:

a system that uses artificial intelligence techniques to convert images of text into audible sound

orthogonal:

elements or objects that are perpendicular to one another; in a logical sense this means that changes in one have no effect on the other

oscillator:

an electronic component that produces a precise waveform of a fixed known frequency; this can be used as a time base (clock) signal to other devices

oscilloscopes:

measuring instruments for electrical circuitry; connected to circuits under test using probes on leads and having small screens that display the signal waveforms

out-of-band:

pertaining to elements or objects that are external to the limits of a certain local area network (LAN)

overhead:

the expense or cost involved in carrying out a particular operation

packet-switched network:

a network based on digital communications systems whereby packets of data are dispatched to receivers based on addresses that they contain

packet-switching:

an operation used in digital communications systems whereby packets (collections) of data are dispatched to receivers based on addresses contained in the packets

packets:

collections of digital data elements that are part of a complete message or signal; packets contain their destination addresses to enable reassembly of the message or signal

paradigm:

an example, pattern, or way of thinking

parallel debugging:

specialized approaches to locating and correcting errors in computer programs that are to be executed on parallel computing machine architectures

parallel processing:

the presence of more than one central processing unit (CPU) in a computer, which enables the true execution of more than one program

parametric:

modeling a system using variables or parameters that can be observed to change as the system operates

parity:

a method of introducing error checking on binary data by adding a redundant bit and using that to enable consistency checks

pattern recognition:

a process used by some artificial-intelligence systems to identify a variety of patterns, including visual patterns, information patterns buried in a noisy signal, and word patterns imbedded in text

PDF:

the acronym for Portable Document Format, developed by Adobe Corporation to facilitate the storage and transfer of electronic documents

peer-to-peer services:

the ways in which computers on the same logical level can interoperate in a structured network hierarchy

permutations:

significant changes or rearrangement

personal area networking:

the interconnectivity of personal productivity devices like computers, mobile telephones, and personal organizers

personal digital assistants (PDA):

small-scale hand-held computers that can be used in place of diaries and appointment books

phosphor:

a coating applied to the back of a glass screen on a cathode ray tube (CRT) that emits light when a beam of electrons strikes its surface

photolithography:

the process of transferring an image from a film to a metal surface for etching, often used in the production of printed circuit boards

photonic switching:

the technology that is centered on routing and managing optical packets of digital data

photons:

the smallest fundamental units of electromagnetic radiation in the visible spectrum—light

photosensitive:

describes any material that will change its properties in some way if subjected to visible light, such as photographic film

picoseconds:

one-millionth of a millionth of a second (one-trillionth, or 10-12)

piezoelectric crystal:

an electronic component that when subjected to a current will produce a waveform signal at a precise rate, which can then be used as a clock signal in a computer

PIN (personal identification number):

a password, usually numeric, used in conjunction with a cryptographic token, smart card, or bank card, to ensure that only an authorized user can activate an account governed by the token or card

ping sweeps:

technique that identifies properties belonging to a server computer, by sending it collections of "ping" packets and examining the responses from the server

piracy:

the unlawful copying and redistribution of computer software, ignoring the copyright and ownership rights of the publisher

pixel:

a single picture element on a video screen; one of the individual dots making up a picture on a video screen or digital image

pixilation:

the process of generating animation, frame by frame

plug-in:

a term used to describe the way that hardware and software modules can be added to a computer system, if they possess interfaces that have been built to a documented standard

pneumatic:

powered by pressurized air, supplied through tubes or pipes

polarity:

the positive ( ) or negative ( ) state of an object, which dictates how it will react to forces such as magnetism or electricity

polarizer:

a translucent sheet that permits only plane-polarized light to pass through, blocking all other light

polygon:

a many-sided, closed, geometrical figure

polynomial:

an expression with more than one term

polypeptide:

the product of many amino acid molecules bonded together

population inversion:

used in quantum mechanics to describe when the number of atoms at higher energy levels is greater than the number at lower energy levels—a condition needed for photons (light) to be emitted

port:

logical input/output points on computers that exist in a network

port scans:

operations whereby ports are probed so that information about their status can be collected

potentiometer:

an element in an electrical circuit that resists current flow (a resistor) but the value of the resistance can be mechanically adjusted (a variable resistor)

predicate calculus:

a branch of logic that uses individuals and predicates, or elements and classes, and the existential and universal quantifiers, all and some, to represent statements

privatized:

to convert a service traditionally offered by a government or public agency into a service provided by a private corporation or other private entity

progenitor:

the direct parent of something or someone

propositional calculus:

a branch of logic that uses expressions such as "If ... then ..." to make statements and deductions

proprietary:

a process or technology developed and owned by an individual or company, and not published openly

proprietary software:

software created by an individual or company that is sold under a license that dictates use and distribution

protocol:

an agreed understanding for the sub-operations that make up a transaction, usually found in the specification of inter-computer communications

prototype:

a working model or experimental investigation of proposed systems under development

pseudocode:

a language-neutral, structural description of the algorithms that are to be used in a program

public key information:

certain status and identification information that pertains to a particular public key (i.e., a key available for public use in encryption)

public key infrastructure (PKI):

the supporting programs and protocols that act together to enable public key encryption/decryption

punched card:

a paper card with punched holes which give instructions to a computer in order to encode program instructions and data

quadtrees:

data structures resembling trees, which have four branches at every node (rather than two as with a binary tree); used in the construction of complex databases

quality-of-service (QoS):

a set of performance criteria that a system is designed to guarantee and support as a minimum

quantification:

to quantify (or measure) something

quantum-dot cellular automata (QCA):

the theory of automata as applied to quantum dot architectures, which are a proposed approach for the development of computers at nanotechnology scales

quantum mechanical:

something influenced by the set of rules that govern the energy and wave behavior of subatomic particles on the scale of sizes that are comparable to the particles themselves

queue:

the ordering of elements or objects such that they are processed in turn; first-in, first-out

radar:

the acronym for RAdio Direction And Ranging; a technique developed in the 1930s that uses frequency shifts in reflected radio waves to measure distance and speed of a target

radio telescopes:

telescopes used for astronomical observation that operate on collecting electromagnetic radiation in frequency bands above the visible spectrum

random access memory (RAM):

a type of memory device that supports the nonpermanent storage of programs and data; so called because various locations can be accessed in any order (as if at random), rather than in a sequence (like a tape memory device)

raster:

a line traced out by a beam of electrons as they strike a cathode ray tube (CRT)

raster scan pattern:

a sequence of raster lines drawn on a cathode ray tube such that an image or text can be made to appear

read only memory (ROM):

a type of memory device that supports permanent storage of programs

real-time:

a system, often computer based, that ensures the rates at which it inputs, processes, and outputs information meet the timing requirements of another system

recursive:

operations expressed and implemented in a way that requires them to invoke themselves

relational database:

a collection of records that permits logical and business relationships to be developed between themselves and their contents

relay contact systems:

systems constructed to carry out logic functions, implemented in relays (electromechanical switches) rather than semiconductor devices

resistors:

electrical components that slow the flow of current

retinal scan:

a scan of the retina of the eye, which contains a unique pattern for each individual, in order to identify (or authenticate) someone

robotics:

the science and engineering of building electromechanical machines that aim to serve as replacements for human laborers

routers:

network devices that direct packets to the next network device or to the final destination

routing:

the operation that involves collecting and forwarding packets of information by way of address

satellite:

an object that orbits a planet

scalar:

a quantity that has magnitude (size) only; there is no associated direction or bearing

scalar processor:

a processor designed for high-speed computation of scalar values

schematic:

a diagrammatic representation of a system, showing logical structure without regard to physical constraints

scripting languages:

modern high-level programming languages that are interpreted rather than compiled; they are usually cross-platform and support rapid application development

Secure Sockets Layer (SSL):

a technology that supports encryption, authentication, and other facilities and is built into standard UNIX communication protocols (sockets over TCP/IP)

semantics:

the study of how words acquire meaning and how those meanings change over time

semiconductor:

solid material that possesses electrical conductivity characteristics that are similar to those of metals under certain conditions, but can also exhibit insulating qualities under other conditions

semiconductor diode laser:

a diode that emits electromagnetic radiation at wavelengths above about 630 nanometers, creating a laser beam for industrial applications

sensors:

devices that can record and transmit data regarding the altitude, flight path, attitude, etc., so that they can enter into the system's calculations

sequentially:

operations occurring in order, one after another

server:

a computer that does not deal directly with human users, but instead handles requests from other computers for services to be performed

SGML:

the acronym for Standard Generalized Markup Language, an international standard for structuring electronic documents

shadow mask:

a metal sheet behind the glass screen of a cathode ray tube (CRT) that ensures the correct color phosphor elements are struck by the electron beams

shareware:

a software distribution technique, whereby the author shares copies of his programs at no cost, in the expectation that users will later pay a fee of some sort

Sherman Antitrust Act:

the act of the U.S. Congress in 1890 that is the foundation for all American anti-monopoly laws

signaling protocols:

protocols used in the management of integrated data networks that convey a mix of audio, video, and data packets

SIGs:

short for "Special Interest Group," SIGs concentrate their energies on specific categories of computer science, such as programming languages or computer architecture

silica:

silicon oxide; found in sand and some forms of rock

silicon:

a chemical element with symbol Si; the most abundant element in the Earth's crust and the most commonly used semiconductor material

silicon chip:

a common term for a semiconductor integrated circuit device

Silicon Valley:

an area in California near San Francisco, which has been the home location of many of the most significant information technology orientated companies and universities

silver halide:

a photosensitive product that has been used in traditional cameras to record an image

simplex:

uni-directional communication over a single communication channel

simputers:

simple to use computers that take on the functionality of personal computers, but are mobile and act as personal assistants and information organizers

sine wave:

a wave traced by a point on the circumference of a circle when the point starts at height zero (amplitude zero) and goes through one full revolution

single-chip:

a computer system that is constructed so that it contains just one integrated circuit device

slide rule:

invented by Scotsman John Napier (1550-1617), it permits the mechanical automation of calculations using logarithms

smart card:

a credit-card style card that has a microcomputer embedded within it; it carries more information to assist the owner or user

smart devices:

devices and appliances that host an embedded computer system that offers greater control and flexibility

smart matter:

materials, machines, and systems whose physical properties depend on the computing that is embedded within them

social informatics:

a field of study that centers on the social aspects of computing technology

softlifting:

the act of stealing software, usually for personal use (piracy)

software-defined networks (SDNs):

the same as virtual private networks (VPNs), where the subscriber can set up and maintain a communications system using management software, on a public network

sonar:

the science and engineering of sound propagation in water

SONET:

the acronym for Synchronous Optical NETwork, a published standard for networks based on fiber optic communications technology

sound card:

a plug-in card for a computer that contains hardware devices for sound processing, conversion, and generation

source code:

the human-readable programs that are compiled or interpreted so that they can be executed by a computing machine

speech recognition:

the science and engineering of decoding and interpreting audible speech, usually using a computer system

spider:

a computer program that travels the Internet to locate web documents and FTP resources, then indexes the documents in a database, which are then searched using software that the search engine provides

spreadsheet:

an accounting or business tool that details numerical data in columns for tabulation purposes

static:

without movement; stationary

stellar:

pertaining to the stars

subnet:

a logical section of a large network that simplifies the management of machine addresses

supercomputer:

a very high performance computer, usually comprised of many processors and used for modeling and simulation of complex phenomena, like meteorology

superconductivity:

the property of a material to pass an electric current with almost no losses; most metals are superconductive only at temperatures near absolute zero

swap files:

files used by an operating system to support a virtual memory system, in which the user appears to have access to more memory than is physically available

syllogistic statements:

the essential tenets of western philosophical thought, based on hypotheses and categories

synchronization:

the time domain ordering of events; often applied when events repeatedly occur simultaneously

synchronized:

events occurring at specific points in time with respect to one another

synchronous:

synchronized behavior

synergistic:

relating to synergism, which is the phenomenon whereby the action of a group of elements is greater than their individual actions

syntactic analyzer:

a part of a compiler that scans program source code ensuring that the code meets essential language rules with regard to structure or organization

syntax:

a set of rules that a computing language incorporates regarding structure, punctuation, and formatting

tangible:

of a nature that is real, as opposed to something that is imaginary or abstract

task partitioning:

the act of dividing up work to be done so that it can be separated into distinct tasks, processes, or phases

taxonomy:

the classification of elements or objects based on their characteristics

TCP:

the acronym for Transmission Control Protocol; a fundamental protocol used in the networks that support the Internet (ARPANET)

TCP/IP networks:

interconnected computer networks that use Transmission Control Protocol/Internet Protocol

TCP/IP protocol suite:

Transmission Control Protocol/Internet Protocol; a range of functions that can be used to facilitate applications working on the Internet

telegraph:

a communication channel that uses cables to convey encoded low bandwidth electrical signals

telemedicine:

the technology that permits remote diagnosis and treatment of patients by a medical practitioner; usually interactive bi-directional audio and video signals

telemetry:

the science of taking measurements of something and transmitting the data to a distant receiver

teleoperation:

any operation that can be carried out remotely by a communications system that enables interactive audio and video signals

teletype:

a machine that sends and receives telephonic signals

terabyte:

one million million (one trillion, or 1012) bytes

thermal ignition:

the combustion of a substance caused by heating it to the point that its particles have enough energy to commence burning without an externally applied flame

thermodynamic:

relating to heat energy

three-body problem:

an intractable problem in mechanics that involves the attempts to predict the behavior of three bodies under gravitational effects

thumbnail:

an image which is a scaled down copy of a much larger image; used to assist in the management of a large catalog of images

time lapse mode:

to show a sequence of events occurring at a higher than natural speed so it looks like it is happening rapidly rather than in real time

title bar:

the top horizontal border of a rectangular region owned by a program running in a graphical user interface (GUI); it usually contains the program name and can be used to move the region around

tomography:

the process of capturing and analyzing X-ray images

T1 digital circuitry:

a type of digital network technology that can handle separate voice and/or digital communications lines

topographic:

pertaining to the features of a terrain or surface

topology:

a method of describing the structure of a system that emphasizes its logical nature rather than its physical characteristics

trademark rights:

a trademark is a name, symbol, or phrase that identifies a trading organization and is owned by that organization

trafficking:

transporting and selling; especially with regard to illegal merchandise

training data:

data used in the creation of a classifier

transaction processing:

operations between client and server computers that are made up of many small exchanges that must all be completed for the transaction to proceed

transducers:

devices that sense a physical quantity, such as temperature or pressure, and convert that measurement into an electrical signal

transistor:

a contraction of TRANSfer resISTOR; a semiconductor device, invented by John Bardeen, Walter Brattain, and William Shockley, which has three terminals; can be used for switching and amplifying electrical signals

translational bridges:

special network devices that convert low-level protocols from one type to another

Transmission Control Protocol (TCP):

a stream-orientated protocol that uses Internet Protocol (IP); it is responsible for splitting data into packets, transferring it, and reassembling it at the receiver

transmutation:

the act of converting one thing into another

trigonometry:

a branch of mathematics founded upon the geometry of triangles

triodes:

nearly obsolete electronic devices constructed of sealed glass tubes containing metal elements in a vacuum; triodes were used to control electrical signals

Trojan horse:

potentially destructive computer program that masquerades as something benign; named after the wooden horse employed by the Acheans to conquer Troy

tunneling:

a way of handling different communication protocols, by taking packets of a foreign protocol and changing them so that they appear to be a locally known type

Turing machine:

a proposed type of computing machine that takes inputs off paper tape and then moves through a sequence of states under the control of an algorithm; identified by Alan Turing (1912-1954)

1200-baud:

a measure of data transmission; in this case the rate of 1200 symbols (usually bits) per second

twisted pair:

an inexpensive, medium bandwidth communication channel commonly used in local area networks

ubiquitous:

to be commonly available everywhere

ultrasonic:

the transmission and reception of sound waves that are at frequencies higher than those audible to humans

Uniform Resource Locator (URL):

a reference to a document or a document container using the Hypertext Transfer Protocol (HTTP); consists of a hostname and path to the document

Universal Product Code (UPC):

the first barcode standard developed in 1973 and adopted widely since

UNIX:

operating system that was originally developed at Bell Laboratories in the early 1970s

uplinks:

connections from a client machine to a large network; frequently used when information is being sent to a communications satellite

vacuum tube:

an electronic device constructed of a sealed glass tube containing metal elements in a vacuum; used to control electrical signals

valence:

a measure of the reactive nature of a chemical element or compound in relation to hydrogen

variable:

a symbol, such as a string of letters, which may assume any one of a set of values known as the domain

vector graphics:

graphics output systems whereby pairs of coordinates are passed to the graphics controller, which are interpreted as end points of vectors to be drawn on the screen

vector processing:

an approach to computing machine architecture that involves the manipulation of vectors (sequences of numbers) in single steps, rather than one number at a time

vector supercomputer:

a highly optimized computing machine that provides high performance using a vector processing architecture

velocities:

vector quantities that have a magnitude or speed and a direction

Venn diagrams:

diagrams used to demonstrate the relationships between sets of objects, named after John Venn, a British logician

venture capitalists:

persons or agencies that speculate by providing financial resources to enable product development, in the expectation of larger returns with product maturity

video capture cards:

plug-in cards for a computer that accepts video input from devices like televisions and video cameras, allowing the user to record video data onto the computer

video compression algorithms:

special algorithms applied to remove certain unnecessary parts of video images in an attempt to reduce their storage size

virtual channel connection:

an abstraction of a physical connection between two or more elements (or computers); the complex details of the physical connection are hidden

virtual circuit:

like a virtual channel connection, a virtual circuit appears to be a direct path between two elements, but is actually a managed collection of physical connections

Virtual Private Networks (VPNs):

a commercial approach to network management where privately owned voice and data networks are set up on public network infrastructure

virtual reality (VR):

the use of elaborate input/output devices to create the illusion that the user is in a different environment

virtualization:

as if it were real; making something seem real, e.g. a virtual environment

visible speech:

a set of symbols, comprising an alphabet, that "spell" sounds instead of words

visualization:

a technique whereby complex systems are portrayed in a meaningful way using sophisticated computer graphics systems; e.g., chemical molecules

volatile:

subject to rapid change; describes the character of data when current no longer flows to a device (that is, electrical power is switched off)

waveform:

an abstraction used in the physical sciences to model energy transmission in the form of longitudinal or transverse waves

web surfers:

people who "surf" (search) the Internet frequently

wide area network (WAN):

an interconnected network of computers that spans upward from several buildings to whole cities or entire countries and across countries

wireless lavaliere microphones:

small microphones worn around the speakers' necks, which attach to their shirts

wireless local area network (WLAN):

an interconnected network of computers that uses radio and/or infrared communication channels, rather than cables

workstations:

computers (usually within a network) that interact directly with human users (much the same as "client computers")

xerography:

a printing process that uses electrostatic elements derived from a photographic image to deposit the ink

XML:

the acronym for eXtensible Markup Language; a method of applying structure to data so that documents can be represented