Fiber Optics Illustrated Dictionary - Part 57 ppt

Kao, Charles K.1933- A Chinese engineer and significant pioneer in fiber optic communications, Kao studied in Britain and became head of the opti-cal communication program at ITT's Stan

Fiber Optics Illustrated Dictionary

Kalman filter The discrete Kalman filter (DKF)

at-tempts to estimate the state of a

discrete-time-con-trolled process The extended Kalman filter (EKF)

handles nonlinear situations by linearizing (e.g., with

partial derivatives) about the current mean and

co-variance

The Kalman filter is now an important aspect of

so-nar and radar tracking, guidance, and navigation

sys-tems It has also been used in satellite orbit

calcula-tions for various space missions Recently, fiber

op-tic gyroscopes (FOGs) in combination with Kalman

filters, have been used in mobile robot systems The

Kalman filter fuses the FOG sensor data with the

ro-bot odometer to provide more accurate dead

reckon-ing than is possible through traditional odometric

systems in accessible price ranges

Kangaroo NetworkA commercial

hardware/soft-ware product from SpartacuslFibronics designed to

enable ffiM mainframes to intercommunicate with

other networks using TCPIIP

Kangaroo Working GroupAworking group on

tele-communications and the information society that

works with the European Internet Foundation

look-ing into issues associated with creatlook-ing a level

play-ing field in terms of Internet use and access in

Eu-rope, ensuring a balance between private industry and

government The Kangaroo Group has been actively

involved in conferences since the mid-1980s and has

actively debated Internet regulations and barriers to

the use of cyberspace

Kao, Charles K.(1933- ) A Chinese engineer and

significant pioneer in fiber optic communications,

Kao studied in Britain and became head of the

opti-cal communication program at ITT's Standard

Tele-communications Laboratories, Harlow, U.K., in

De-cember 1964 Along with G Hockham, Kao

cham-pioned the idea ofsingle-mode optical fiber

transmis-sion systems and coauthored "Dielectric-Fiber

Sur-face Waveguides for Optical Frequencies" inProc.

IEEE(1966) He followed this up with work on the

structure of fiber communications and subsystems

Kao and Hockham were correct in proposing that loss

in fiber signals was due to impurities in the

transmis-sion medium rather than inherent limitations in the

glass itself

During the period 1987-1996, Kao taught and

be-came president of the Chinese University of Hong

Kong He became a Trustee for the S.K Vee

Medi-cal Foundation in 1990 and is chairman ofTranstech

Services Ltd He has received many honors from

en-gineering societies See Hyde,J.Franklin; Kapani,

Narinder; Keck, Donald

Kapani, Narinder Singh(ca 1930- ) A prolific

In-dian inventor, Kapani has been awarded more than

150 patents for various instruments and laser

tech-nologies In 1954, inNature, Kapani and Hopkins

described a means to clad optical fibers to keep the

light within the waveguide This was an important

milestone in optical technologies, greatly extending

the distance over which signals could travel through

a fiber waveguide The following year, Kapani

developed a way to fabricate high-quality fiber

filaments and coined the termfibre optics.By2000, Kapani had founded a series of companies, includ-ing K2 Optronics for concentratinclud-ing on fiber optic communication devices See Hansell, Clarence; Kao, Charles

Kapor, Mitchell "Mitch"(1950- ) The instigator of several historic high profile computer-related orga-nizations, Mitch Kapor founded Lotus Development Corporation in 1982, and was the designer ofthe well-known Lotus 1-2-3 spreadsheet software In 1990, he cofounded the Electronic Frontier Foundation (EFF),

a nonprofit civil liberties organization Kapor has chaired the Massachusetts Commission on Computer Technology and Law and served on the board of the Computer Science and Technology arm of the Na-tional Research Council, and the NaNa-tional Informa-tion Infrastructure Advisory Council

Karbowiak, Antoni E.Aresearcher at Standard Tele-communications Laboratories in a group established

by Alec Reeves in 1962 Karbowiak and his collabo-rators conducted pioneer work with optical fibers as potential transmission technologies at a time when most scientists considered the lossiness of (uncladded) fiber to be too great to be of any practi-cal value He became a collaborator with a young, talented Chinese engineer, Charles K Kao, who is now considered a significant pioneer in fiber optics

In 1964, Karbowiak left STL to chair the electrical engineering department at the University of New South Wales See Kao, Charles K.; Snitzer, Elias Karnaugh mapA two-dimensional truth lookup table organized to facilitate combination and reduc-tion of Boolean expressions This is useful in digital logic circuit design See Boolean expression Karn's algorithmA mathematical formula for im-proving network round-trip time estimations It grew out of packet radio network algorithms but now is more widely applied In layered network architec-tures, the algorithm helps the transport layer proto-cols distinguish among round-trip time samples It is used in Transmission Control Protocol (TCP) imple-mentations to separate various types of return trans-missions and to establish whether or not to ignore re-transmitted signals.Itis also applied to backofftim-ers in Point-to-Point (PPP) tunneling networks See ATM, Jacobson's algorithm, Point-to-Point Tunnel-ing Protocol

Kawakami, ShojiroA Japanese researcher who has contributed articles about many aspects of fiber op-tic technology, but who is chiefly known for his de-velopment of graded-index fiber and of a "photonic crystal" that acts like a prism in that it can separate optical signals with different wavelengths The tech-nology was developed by Shojiro (Tohoku Univer-sity) and further developed in conjunction with Opto-electronics Laboratories, and NEC, in 1997 This in-vention has potential as part ofadd/drop multiplexer components in dense-wavelength transmission sys-tems, as envisioned by NEC • Kawakami was recognized as a Fellow of the IEEE Society for his contributions to fiber optics,in1997 See Hicks, John; photonic crystal; Yablonovitch, Eli

reader, Kay was inspired by the work of Seymour

Papert at MIT in the 1960s Kay was committed to

the idea that computers should be easy, fun, and

ac-cessible, and began developing what was to become

the Smal1talk object-oriented programming language

He became a group leader at Xerox PARC in the early

1970s, a period when tremendous innovation in mi-

crocomputer technology and user interfaces was

stimulated at the lab

Kazarinov, Rudolf F A Russian physicist and

en-gineer, Kazarinov originally carried out research at

the IOFFE Physico-Technical Institute in St

Peters-burg He then came to theu.s. to conduct research

at the Bell Laboratories Photonics Circuits Research

Department Kazarinov made significant pioneer

theoretical contributions to semiconductor laser

tech-nologies beginning in the early 1960s His

contribu-tions include the double-heterostructure laser,

distrib-uted-feedback (DFB) laser, and intersubband lasers

He also coauthored a number of patents, including

hybrid lasers for optical communications, with Greg

Blonder, Charles Henry, et al

In 1998, Kazarinov was coawarded the prestigious

Rank Prize in optoelectronics for his involvement in

the 1994 development of the quantum-cascade (QC)

laser, along with Federico Capasso See Capasso,

Federico; laser history

Kbps kilobits per second; 1000 bits per second.Itis

sometimes written Kbits/s

KBps kilobytes per second, 1000 bytes per second

It is sometimes writtenKbytes/s.

KDC See key distribution center

KDD 1 Knowledge Discovery in Databases A

branch of artificial intelligence applied to database

query, search, and retrieval 2 Kokusai Denshin

Denwa Company, Ltd A Japanese supplier of

inter-national telecom services, equipment, and facilities

KDDI Corp Japan's second-largest communications

carrier, descended from Kokusai Denshin Denwa

Kabushiki Kaisha (KDD), which was founded in

1953 In April 2001, KDDI announced Java support

for its mobile phone services through its CLDC- and

MIDP-conforming application interface called

KDDI-P

KDD R&D Laboratories, Inc is the research and

de-velopment division It was founded when KDD was

detached from the Nippon Telegraph and Telephone

Public Corporation and moved into a new research

facility for conducting research in international

com-munications in 1960.Itbecame independent ofKDD

in 1998 and was remerged, along with other firms,

in 2000 to become KDDI's R&D division The R&D

lab has developed TDMA technology for satellite

communications, submarine fiber optic cables, G3

facsimile coding technologies, magneto-optical discs,

and data compression and transmission technologies

KDD Fiber Labs, Inc., a KDDI Group Corporation,

develops fiber optics technologies, including WDM

optical amplification and various types of light

sources

KDKA KDKA originated as amateur callsign 8XK,

historically significant Westinghouse Electric radio broadcasting station in Pittsburgh, Pennsylvania that used radio waves to report returns ofthe Harding-Cox Presidential race to the American public, on Novem-ber 2, 1920 This was about 14 years after the earli-est experimental broadcasts and a week after receiv-ing its own official broadcastreceiv-ing license By the fol-lowing year, KDKA was making regular public broadcasts and radio broadcasting was booming, with more than 500 broadcasting stations sprouting up around the country KDKA was still broadcasting under the same callsign more than 80 years later See CFCF; Herrold, Doc; radio history

KEA See Key Exchange Algorithm

Kearney System KS A parts numbering scheme developed for Western Electric telecommunications equipment, named after the town in New Jersey where the plant was located The KS system has gen-erally been superseded with vendor-specific and in-dustry standard codes, although Kearney numbers are still found on some pieces of equipment I

Keck, DonaldB.(1940- ) Keck studied at Michi-gan State University, graduating in 1967 and went to work as a senior research scientist at Coming Glass Works in 1968, becoming involved in fiber-related projects with Robert Hall He subsequently served as director of the Applied Physics division and VP of Optics and Photonics and then became VP and direc-tor of the Optical Physics Technology group Along with Maurer and Schultz, Keck was awarded the National Medal ofTechnology in 2000 for mak-ing low-loss optical transmission fiber a practical re-ality

keepalive interval The period of time between keepalive messages The amount of time depends upon the type ofnetwork and the type ofactivity tak-ing place For example, for a computer process, the interval might be measured in nanoseconds, whereas for a user activity, it might be measured in minutes See keepalive message, keepalive signal

keepalive message Messaging between network de-vices that indicates that a virtual circuit between the two is still active (alive) See keepalive interval, keepalive signal

keepalive signal A network signal transmitted dur-ing times of idleness to keep the circuit from initiat-ing a time-out sequence and terminatinitiat-ing the connec-tion due to lack of activity See keepalive interval, keepalive message

Kelvin balance, ampere balance Ahistorical instru-ment for measuring the absolute value of an electrical current, named after its inventor, William Thompson (Lord Kelvin) It is essentially a galvanometer that measures the force produced by the magnetic field associated with the passage ofcurrent through a con-ductive medium

In one of its historical fabrications, the instrument resembled a small reel-to-reel tape recorder, with two low, flat spools coiled with wires connected to one another in series positioned a few inches apart Apiv-oting beam balance enabled a set of rings to move

Fiber Optics Illustrated Dictionary

freely between the coils A finely incremented

ruler-like gauge stretched the length of the instrument, in

front of the coils, from the outer edge of one to the

other The whole thing was generally encased within

a protective brass and glass enclosure The instrument

was sold with a set ofweights The current to be

mea-sured passed through the wire coils to create an

at-tractive force referenced against a known weight

Two ampere balances were designated as legal

stan-dard instruments in 1894

Kelvin effect When an electric current passes through

a single homogeneous but unequally heated

conduc-tor, heat is absorbed or released This effect is named

after William Thompson (Lord Kelvin)

Kelvin scale A temperature scale proposed by

Will-iam Thompson (Lord Kelvin), based on the efficiency

ofa reversible machine Zero is designated as the

tem-perature of the sink of the machine working

effi-ciently, that is, complete conversion ofheat into work,

a situation possible only at absolute zero on a gas

tem-perature scale Zero degrees Kelvin (0 K) can also

be expressed as -273.15 degrees Celsius (-273 I5°C)

or -459.67 degrees Fahrenheit (-459.67°F)

Kelvin, Lord William Thomson (1824-1907) A

Scottish physicist and mathematician who made

sig-nificant contributions to the field of

thermodynam-ics, and applied his theories to the dynamics and age

of the earth and the universe He utilized the field

concept to explain electromagnetism and its

propa-gation The concept of an all-pervasive "ether" was

still prevalent at the time, so he explained a number

of his observations within this context He also

de-veloped the siphon recorder, a number of types of

voltmeters, and an ampere balance, and was involved

in laying the transatlantic telegraph cable The Kelvin

scale and Kelvin effect are named after him

Kenbak-l A discrete logic microcomputer designed

by JohnV.Blankenbaker, introduced in 1971 as the

Kenbak-I Digital Computer It featured 256 bytes of

memory, three programming registers, and five

ad-dressing modes The controlling switches were on the

front panel of the machine It was advertised in the

September 1971 issue ofScientific American, 3 years

prior to the introduction of the Altair, for only $750

One of the earliest microcomputers, the Kenbak-I

was apparently ahead ofits time Unfortunately, only

40 machines sold over the next 2 years, and the

Cali-fornia-based Kenbak Corporation missed a

signifi-cant business window by a narrow margin One year

after the company closed, the Altair computer kit

caught the attention of hobbyist readers ofPopular

Electronics magazine and sold over 10,000 units.

See Altair, Arkay CT-650, Heathkit EC-I, Intel

MCS-4, Micral, Simon, Sphere System

Kendall effect Distortion in a facsimile record,

caused by faulty modulation of the sideband to

car-rier ratio of the signal

Kennelly, Arthur Edwin (1861-1939) A

British-born American mathematician and engineer who

studied mathematical aspects of electrical circuitry

He also studied the properties of the Earth's

atmo-sphere and its effects on radio waves and suggested that

an ionized layer above the Earth could reflect radio waves, an idea soon after independently published by Oliver Heaviside

Kennelly-Heaviside layer In 1902, A Kennelly and

O Heaviside proposed, independently ofeach other, that an ionized layer surrounding the Earth could serve as a reflecting medium that would hold radia-tion within it This led to the discovery of a number

of regions surrounding Earth and utilization of the characteristics of some of these layers in long-dis-tance wave transmission It also led, in the 1920s, to confirming experiments in which radio signals were bounced off this reflecting layer See Heaviside, Ol-iver; ionosphere; Kennelly, Arthur

Kepler, Johannes (1571-1630) A physicist and

as-tronomer from Swabia (now Austria) who studied the planets and endeavored to mathematically describe planetary motion.In1604, he publishedAstronomiae pars Optica describing light travel, shadows, the

functioning ofthe eye, and other concepts fundamen-tal to modem optics He also made important studies

in optics related to better studying the planets In

1611, he publishedDioptrice which described the

properties oflenses, including inversion and magni-fication, and a new form of telescope now known as the astronomical telescope.Ke~lermay have been the first to use the term "satellite' to describe orbiting moons

Kerberos authentication An authentication system

developed through the MIT Project Athena effort Kerberos is a client/server security mechanism based upon symmetric key cryptography Each user of the Kerberos system is assigned a nonsecret uniqueill

and selects a secret password The secret password

is provided to the Kerberos system and is not intended

to be divulged by either party The user then uses the password to request access from the system The iden-tity of the user is verified by generating a random number and presenting a problem that can likely be solved only by the authentic user, thus providing ac-cess to a message on the system The symmetric na-ture of the system is in the use of the same encryp-tion and decrypencryp-tion key For security purposes, long, randomly selected strings work best with this system

of cryptography; otherwise it may be vulnerable to password-guessing attacks

Kermit Project A nonprofit, self-supporting project

at Columbia University for the support of the Ker-mit Protocol and the development ofKerrnit-related technologies The project also includes information

on documentation, licensing, and technical support for users of the Columbia implementation ofKermit See Kermit Protocol

http://www.columbia.edu/kerrnit/

Kermit Protocol A packet-oriented,

platform-inde-pendent file transfer protocol developed at Colum-bia University in 1981 Hundreds of Kermit imple-mentations support the 7-bit and 8-bit transfer oftext and binary files They are commonly used over asyn-chronous, serially connected local area networks (LANs) and phone lines Kermit is flexible and con-figurable

is checked and acknowledged as it is transferred, but

it is reliable, widespread, and well supported,

espe-cially in academic institutions; when all other

proto-cols fail, it's often the one which will get the file

trans-fer done There are numerous terminal emulators

based on Kermit, with VT52 and VT100 versions

being common Telnet, an important protocol for

re-motely connecting to a network host, has also been

implemented with Kermit

Kermit is a workhorse, but its use in its original form

has declined Most local area networks and the

In-ternet now use other network connection and file

transfer mechanisms such as ATM, Ethernet, and FTP,

but traditional Kermit is still useful for phone links

and small networks interconnected with basic serial

connections

Updated versions of Kermit may greatly extend its

useful life Internet Kermit Service is a file transfer

service described by da Cruz and Altman at

Colum-bia University based on a combination of the widely

used Telnet Protocol and Kermit Protocol It supports

both anonymous and authenticated access Kermit

over Telnet enables the traversal of firewalls and a

number of security options By providing some

ad-vantages over File Transfer Protocol (FTP), this

Ker-mit configuration is a practical option for distributed

networks, including the Internet The registered

lANA port for Kermit connections is 1649

Kermit is an open freely distributable protocol, so it

can be used for software applications development,

but Columbia's implementation of the Kermit

proto-col is copyrighted See FTP, Kermit Project,

XMo-dem, YMoXMo-dem, ZModem See RFC 2839, RFC 2840

kernel I Line within a conductor along which the

current-resulting magnetic intensity is zero 2 Low

level of an operating system at which processes and

resources (such as memory and drivers) are created,

allocated, and managed Functions and operations at

the kernel level form a bridge between hardware and

software resources and are mostly or completely

transparent to the user

Kerr cellAdevice used to modulate light in

conjunc-tion with polarizers The cell contains electrodes to

direct the necessary electric field for inducing the

Kerr electro-optical effect and the material being

in-fluenced by the combination of the field and a beam

ofpolarized light Photodetectors may be used in

con-junction with the Kerr cell to determine if or when

the effect occurs Kerr cells have been used in the

fabrication of high-speed optical shutters

Kerr effectThere are actually two Kerr effects named

after John Kerr, so it is best to specify the one of

rel-evance For simplicity of reference, they are

some-times abbreviated as electro-optical Kerr effect (EKE)

and magneto-optical Kerr effect (MOKE), especially

in the field of microscopy See scanning near-field

magneto-optical microscope

Kerr electro-optical effectA phenomenon

discov-ered by John Kerr in 1875 It is an electro-optical

ef-fect in which certain substances become double

re-fracting (birefringent) in the presence of strong

elec-come double refracting in smaller electric fields In other words, a single incident ray oflight is refracted

as two, with the two rays oscillating in mutually per-pendicular planes Isotropic liquids or gas, for ex-ample, show the Kerr effect and become optically anisotropic when subjected to a consistent electric field perpendicular to a beam of light

To account for the effect, it is theorized that the ap-plication ofthe electro-optical energy causes a reori-entation ofa material's molecular structure Since the effect is not universal across materials and levels of electromagnetic influence, it is often studied with cer-tain parameters held within controlled limits, such as the constancy ofthe electric field and the wavelengths

of light

Since the Kerr effect can be induced through con-trolled conditions and occurs quickly, various re-searchers have suggested that it may have practical applications in troubleshooting optical transmissions

or in increasing bandwidth in optical communications systems See Kerr cell, Pockels effect

Kerr magneto-optical effectThe change in a light beam from plane polarized to elliptically polarized when it is reflected from the reflective surface of an electromagnet The degree ofrotation is directly pro-portional to the degree ofmagnetization ofthe reflec-tive material The transmissive aspects of this effect were first observed and described by Michael Fara-day in the 1840s and researched further by John Kerr three decades later as to its reflective properties Be-cause of their relationship, the Faraday and Kerr ef-fects are often described together

This magneto-optical effect is useful for studying magnetic effects in superlattices and giant magneto-resistive (GMR) effects GMR technology was dis-covered in the late 1980s and has since developed into

a new, highly sensitive sensor design for disk drives The effect can also be put into practical use for mea-suring current in power lines using a polarized laser

to measure the degree ofrotation See Faraday effect, giant magneto-resistance

Kerr, John(1824-1907) A Scottish-born physicist best known for discovering and describing the Kerr electro-optical effect Kerr carried out research un-der the direction ofWilliam Thompson (Lord Kelvin) See Kerr electro-optical effect

keV Abbreviation for kiloelectronvolt

KevlarThe DuPont tradename for a strong, synthetic multipurpose material that is, ounce-per-ounce, about five times as strong as steel.Inthe 1960s, a new liq-uid crystal polymer fiber was invented by Stephanie Kwolek; Kevlar is the commercial embodiment of this fiber Kwolek also invented Nomex, a fiber used

in electrical insulation

Kevlar is used in applications where strong, light, flexible materials are needed, such as bulletproof vests and protective sheathings for sensitive or electrically active materials Kevlar tape and Kevlar strength members are used in fiber optic cables A water-resistant sheath is often fitted over the Kevlar

or Kevlar-impregnated inner layers for further

Fiber Optics Illustrated Dictionary

protection from the elements (typically PVC or

poly-ethylene) Kevlar is sometimes mixed with building

materials to increase strength and resilience in the

event ofindustrial vibrations or earthquakes Carbon

steel or ceramic cutters are generally used to cut the

Kevlar components that serve as strength members

in fiber optic cables

key n 1 Asmall, physical security device, often made

of metal, inserted into a matching lock receptacle to

lock/unlock or activate/inactivate an object or

struc-ture It's usually the shape that allows a lock to be

opened or closed, but more recent data-compatible

keys may have magnetic stripes rather than physical

indentations 2.Inan image, the overall tone or value

of the image, often used to adjust camera settings to balance the amount of light or to screen out certain colors or light intensities (e.g., chroma key) 3 A switch for opening or closing a circuit 4.Ina data-base, an organizational means to locate desired in-formation without searching the entire content ofthe database 5 On keyboards, keypads, phone pads, etc.,

a small, roughly cubic, raised, movable, input attach-ment intended to be depressed, usually by a finger,

to make a selection 6 The modem equivalent of the switch on an old phone

key, telegraph A signaling device allowing the in-put of code, usually Morse code, and transmits it to the communications channel The key superseded the Key Encryption - Basic Concepts

key agreement An encryption key establishment mechanism that is common to asymmetric

cryptographic exchanges but may also be used in symmetric exchanges In key agreement, a pair of entities, wishing to engage in a secured

communication without prior arrangement, make use of public data (e.g., a public key) to negotiate a common key value unique to their

communication (i.e., not known or used by other entities) When a Diffie-Hellman technique is used, key agreement is arranged without the need to transfer the key See Diffie-Hellman

key center A trusted, centralized distribution point (e.g., separate server machine)

capable of administering the use of key-encrypting "master" keys to encrypt and distribute session keys for secured communications

key confirmation The process of ensuring that participants in a key-secured communication

are legitimate by detennining whether they do indeed possess a shared symmetric key

key distribution center Insymmetric digital cryptography, a key center that provides encryption!

decryption keys to two or more entities that wish to engage in a secured communication through an agreed-upon ,key distribution protocol These keys are often session-related

key escrow A security system component in which part or all of a cryptographic key is

entrusted to a third party to hold "in escrow." The key "bank" or authority is responsible for storing and releasing the keys to a party involved in a communication, provided that party submits proper authorization The authorized recipient can then use the key to decrypt a message

There has been considerable debate over the use of escrow authorities On the one hand, some individuals feel no one should have any part of a communication other than the sending and receiving parties On the other hand, some believe it is necessary to have a third party that can be served a warrant to hand over information critical to the maintenance of national security and the carrying out of law enforcement activities It is also critical, for the system to work, for the authority to be highly reliable, accountable, and secure See key generation, key recovery

key establishment The processes of key generation, storage, and distribution that together

enable a secured key-related communication association to be established key exchange The transmission or recording of a software key with another party, or

swapping among two or more parties See encryption, PGP, key generation key generation The process of creating a software key for security uses Once this has been

done, it is expedient to keep track of information related to keys (location, password, etc.) so that key generation does not have to be done again

Portable devices for generating a key are sometimes used in conjunction with keyless security locks on building premises

key encryption Apersonal or public identifier

in-tended to establish the owner or recipient of a secure

encoded message Key-related negotiations may be

symmetric or asymmetric and may be based upon

public keys, private keys, or a combination of both

Key encryption may be based upon a long-term

es-crow system or upon short-term session-based

com-munications

A public key cryptographic scheme consists ofa

pub-lic key provided openly to anyone who wishes to send

an encrypted message, and aprivate key used by the

recipient to de-encrypt the received message The

Key Encryption chart provides a summary of some

of the basic concepts See certification, Clipper Chip,

cryptography, encryption, Pretty Good Privacy

asymmetric key encryption algorithm similar to the Diffie-Hellman algorithm, that utilizes1024-bit keys

KEA was originally developed by the National Se-curity Agency (NSA) as a classified seSe-curity mecha-nism whose status was changed in June 1998 See Clipper Chip, Diffie-Hellman, key encryption, SKIP-JACK

Key Contact Aservice ofBritish Telecom that com-prises an11th phone number (nonmobile) in addition

to the key numbers kept by a business subscriber in BT's Friends&Family Key Numbers service See key numbers

key illuminationThe lighting of a key on a keypad

or keyboard to signal its status or facilitate its loca-tion The keys may be illuminated to indicate that they

Key Encryption - Basic Concepts, cont

key length The number of symbols, usually expressed in bits or bytes, used in

representing an encryption key In general, the longer the key length, the greater the possible number of ways in which thedatamay be

scrambled to ensure that it cannot be easily decrypted by an unauthorized party

key Iifetimellifespan The time span or expiry date associated with an established

cryptographic key The expiry period or lifespan may be determined in advance by an issuing authority, especially in session-related key assignments, or may be dynamically determined The key lifetime is also determined in part by users If a user loses or forgets or misplaces a key, its effective lifetime has ended even if the capability to use it still exists Some key cryptography systems will explicitly include a parameter that determines the lifespan of a key (e.g., until the session is terminated) The capability to terminate a key is importantinsituations where key assignments must be reused in a dynamic resource-conscious system (e.g., session-related keys) or where the key users may cease to have authority (e.g., terminated employees)

key management protocol A protocol developed to facilitate establishment of a key-administered

transmission between entities wishing to secure the communication through key encryption

key recovery The process of determining the value of a cryptographic key that has

been used to perform an encryption operation Key recovery is a hotly debated political topic since law enforcement agencies have desired and

at times secured the legal and technological capability to recover keys for decrypting secured communications A key "escrow" system that included portions of keys (to facilitate key recovery) was at one time intended to be associated with software products exported out of the

U S Key recovery by governmental agencies was repeatedly proposed and defeated during the 1990s Key encapsulation is a means of storing information about a cryptographic key by encrypting it with another key

so that only authorized recovery agents may decrypt and retrieve the stored key See key escrow

key space The universe or space from which cryptographic key values may be

taken.Itis the total number of distinct transformations which may be supported by a cryptographic scheme, in other words, the realm of possible variations possible

key update The updating or derivation of a new key from an existing key Also

called rekey

···'.·.?···.•···.~·.• I I · · · •.

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::~-Fiber Optics Illustrated Dictionary

are active (or pending), as in a multiline phone

sys-tem, or to enable them to be seen in low-light

condi-tions (e.g., a burglar alarm keypad) Steady

illumi-nation or various flashing speeds and patterns may

be used to indicate the line or device status

key map A table that translates keyboard input

val-ues from one configuration to another, commonly

used in computer software to transcribe the alphabets

of a number oflanguages This is useful for

transla-tion, alternate typing keyboard setups (e.g.,

Dvorak), graphics, and music applications

key numbers Telecommunications numbers of

par-ticular interest, such as the phone numbers of

fre-quently called family and close friends or business

associates British Telecom (BT) has a key numbers

service that can be managed on the Web The Web

portal enables customers to set up and manage the

Friends&Family Key Numbers list associated with

their phone accounts This service is without charge

for residential and business customers for up to ten

numbers and may include up to two mobile numbers

Itis likely that this type of Web access to

telecom-munications services will increase, just as online

banking is increasing, due to its 24-hour availability

and update convenience; the user doesn't have to wait

to call service representatives during business hours

key performance indicator KPI A statistic intended

to indicate effectiveness in specified key aspects

which are typically industry-specific.Inthe

telecom-munications industry KPIs may comprise the

fre-quency or duration ofcalls, revenue per call, purchase

trends, etc KPIs are used to plan budgets, inventory,

and investment, financing, and growth strategies

Key Performance Indicator KPI A commercial

database to track mobile operators' key performance

indicators such as minutes ofuse, chum, average

rev-enue per user, and acquisition costs The system was

first released by EMC, a U.K firm, in April 2000,

and is incorporated into EMC World Cellular

Infor-mation Services The system computes average

sta-tistics for each KPI for regions and reporting periods

key pulsing KP A system for sending multifrequency

signals from a pushbutton key telephone through a

phone circuit to establish a connection It is

some-times called key sending.Inolder, manually operated

toll stations, pulsing was sometimes used by

opera-tors instead ofdialing Dial-operated pulse phones are

on the decline, with touchtone phones replacing them

key service unit, key system unit KSU The

inter-nal electronics and logic that enable the selection of

lines and other options in a key telephone system

This may be a small cabinet installed in a closet or

some other area where the lines are not cluttering up

the environment or causing an obstruction See key

telephone system

key station Master station from which broadcasts

originate

key telephone system, key system KTS Amultiline

telephone system in which individual phones have

multiple keys or buttons that the user presses to

se-lect the line over which she or he wishes to

commu-nicate.Inlarger multiline key systems, there may be

a main console through which the calls are channeled This is not the same as a private branch system, in which a separate switching system is associated with the phones.Inthe key system, which is used in many small offices, the switching and selection of lines is done manually by the user Some larger offices with private branch exchanges will use a hybrid system which also incorporates one or more key systems, sometimes in individual departments New key sys-tems commonly feature programmable function keys and LED status displays See key service unit, pri-vate branch exchange

keyboard Ahardware peripheral interface device for detecting and transmitting user input to a computer-ized system through keys with assigned functional values Descended from typewriter keyboards and typically arranged according to the historic

"QWERTY" typewriter layout which, ironically, was designed to slow down typing in order to prevent key jamming on old manual typewriters

A variety of keyboard layouts and shapes are avail-able for various computer systems, some with better ergonomics than those which typically come with the system See keypad; keyboard, touch-sensitive keyboard buffer Recent input is typically stored in temporary memory in order to prevent loss or cor-ruption in the event that the system was not yet ready

to respond at the time that the keys were pressed keyboarding Striking keys on a computer or other digital keyboard This is distinct from typing in that typing is generally intended to immediately translate the keystroke into an image on a printing surface Keyboarding, on the other hand, enables the key-stroke to be stored and manipulated for a variety of purposes, including word processing, chatting, sig-nalin~, or printing at a later time It is possible to

"type' on a computer keyboard with a software pro-gram designed to immediately send the key to a print-ing device, but this is rarely used due to the greater convenience of editing the keyboard strokes before printing (or sending them electronically without print-ing)

keying A means of modulating a signal This can be done in a number of ways, by varying the amplitude, frequency, or phase of a signal See amplitude shift keying, frequency shift keying, Gaussian minimum shift keying, quadrature phase shift keying, phase shift keying

keypad A key-based physical interface for various calculators, dedicated word processors, security sys-tems, and computing devices It is usually a compact group of functionally related keys, often consisting

of numbers aligned in rows and columns to facilitate finger access A larger grouping, as on computers or typewriters, is usually called akeyboard.

On a calculator, the keypad is generally configured

as three or four columns by five or six rows, depend-ing upon how many extra function keys (memory, clear, print, etc.) are integrated into the key pad lay-out Many security entry devices and alarm systems are managed through a keypad with nine or twelve keys for entering numeric codes or alphanumeric

may trigger other mechanisms (e.g., a security

cam-era) if used or if suspicious codes are entered See

keyboard, numeric keypad

keysheetAnadministrative plan for phone extensions

that tracks and illustrates the connections and features

assigned to that phone Keysheets are practical in

in-stitutional environments with many extensions,

par-ticularly if the extension phones have different

capa-bilities and dialing privileges A keysheet is even

more important for keeping track if the phones are

also individually programmable or if they are

relo-cated on a regular basis

Software exists for developing keysheet connection

plans, diagrams, and overlays Electronic forms are

now also commonly used for individual members of

departments to list the phones, faxes, and modems

for inclusion in a keysheet database

keystoningA visual aberration which occurs when

an image is projected on a surface off-plane, that is,

on a surface which is at an angle to the plane of the

surface of the projecting lens Thus, if a rectangular

image from a film or slide projector, for example,

were projected on a movable screen which was

crooked, the image would be wide on one side and

narrow on the other See barrel distortion

kHzabbrev.kilohertz, 1000 hertz See hertz

kiddie camA video camera installed to monitor the

activities ofchildren, often over a network These are

common in household nurseries and increasingly

common in daycare facilities Some of these cams

have been interfaced with the Internet to enable

par-ents and caregivers to remotely monitor the

activi-ties of children For the safety and privacy of

chil-dren being monitored by Web-based kiddie cams,

some kiddie cam services require a password to login

to the remote viewing site

Unfortunately, the kiddie cam moniker is also used

by some sites to promote pornographic images ofgirls

and boys who have been covertly photographed or

who are too young to understand how their image is

being used This type of exploitation is generally

il-legal, but the sites promoting child pornography

man-age to stay online long enough for the imman-ages to be

downloaded and shared among thousands or millions

of Internet users

KIFSee Knowledge Interchange Format

Kilby, Jack St Clair(1923- ) An American

inven-tor and Texas Instruments Incorporated (TI)

em-ployee who was involved in designing the first

inte-grated circuit chip, shortly after joining TI The

de-velopment catapulted the miniaturization and speed

of electronics into a new level of evolution Kilby's

first IC was introduced in September 1958, shortly

before Fairchild engineers developed historic ICs that

were, for some time, considered to be the fIrst (the

patent was awarded to Noyce even as Kilby's

appli-cation was still being assessed) Texas Instruments

has named the Kilby Center, a silicon manufacturing

research facility, in his honor

Kilby is also responsible for providing miniaturized

electronics that supported the portable calculator

to be small and sparing on power consumption.In

October 2000, Kilby's contributions were acknowl-edged with a Nobel Prize in physics jointly with two other scientists See integrated circuit; Noyce, Rob-ert; transistor

KiidaU, Gary(1942-1994) American educator and pioneer software developer Kildall developed CP/M (Control Program/Monitor) over a number of years, beginningin1973, with contributions from his stu-dents, when he was a professor of computer science

at a California naval school Kildall developed CP/M into a popular, widely used, text-oriented, 8-bit op-erating system in the late 1970s

Kildalllater founded InterGalactic Digital Research, which became Digital Research (DR), to market his software products Digital Research developed GEM,

an early graphical user operating system which pre-dated functional versions of Windows DR also cre-ated DR-DOS, which was competitive with MS-DOS, and claimed by many to be superior

Kildall is also known for developing PLIM prior to CP/M, the first programming language for the his-toric Intel 4004 chip, and for co-authoring a floppy controller interface in 1973 with John Torode

In the ensuing years, Gary Kildalliost one political battle after another with the rapidly expanding Micro-soft, and Digital Research never flourished as one might expect for a company so often in the forefront

of technology Digital Research had a history ofcre-ating good products, but was overshadowed by its larger, more aggressive competitor At one point DR won a lawsuit against Microsoft, butitmay have been

a case oftoo little too late; at that point Microsoft had

so much momentum, it was unlikely Kildall and DR could regain their market share Kildall is acknowl-edged as the original developer of many significant technologies for the microcomputer industry, but unfortunate circumstances cut short his life at 52 See CP/M; Gates, William

kill 1 Remove or delete, as a word, line, or file

2 Abruptly or prematurely terminate a process or broadcast

kill file 1.Anemail or newsgroup filter that sends messages from particular people, or on particular top-ics, to the "bit bucket," that is, they are shuffled off

to a file that never gets read, or is deleted unread 2

A list of users banned or otherwise controlled from access to remote terminals or online chat seIVices See kill command

killcommandA software control command avail-able to operators on various chat systems to discon-nect a disruptive member from the site Common rea-sons for killing a user include racial, cultural, or reli-gious slurs, violation of chat rules, illegal activities,

or excessive profanity On Internet Relay Chat (IRC) there is a general set of guidelines and a code of eti-quette to guide channel operators in the appropriate use of the IRC /kill command

killmessage1 A textual message transmitted by an operator to a user in a computer-based "chat room"

who is in the process ofbeing removed from the chat

"' '.".•••• "g~l" : • " ' ::~~ :1

Fiber Optics Illustrated Dictionary

area This is an option on most systems for operators

to inform the user as to why he or she is being

re-moved See kill command 2 A software command

sent to stop a process This may be on a single-user

system, a network, or a specialized system such as a

Iransaction system based on digital data cards A kill

message can halt a process that has hung or gotten

out of conlrol, without taking down the operating

system; it can stop suspect activities (e.g., possible

hacking) on a network with remote terminals, or it

can stop the use of a suspected stolen or lost ATM

card 3.Anintroductory message played over a

tele-phone connection when the user has called a local or

long-distance pay-per-call service It may include

consumer protection information or specifics about

restrictions or potential call costs Calls that may

ex-ceed charges of a specified amount may be required

to include a kill message in the first few seconds of

the call to allow the caller to hang up before charges

accrue

In spite of mandatory preambles and kill messages,

there were complaints to and by the Federal Trade

Commission (FTC) in the mid-1990s that telephone

service vendors were abusing so-called toll-free

1-800 numbers in a variety of ways, including

for-warding 1-800 calls to 1-900 numbers or otherwise

manipulating the system to rack up charges on the

callers' phone bills

KILLmessage I A software message that causes a

client/server connection to be closed by the related

server for a variety of reasons, depending upon the

system For example, in Internet Relay Chat, it may

be automatically invoked when duplicate nickname

entries are detected; both entries are removed with

the expectation that only a single nickname will

re-appear This maintains global uniqueness The KILL

message may be available to operators but ideally

should be handled by servers See RFC 1459

kilo- (abbrev - k or K) Prefix for one thousand

(1000), orJOl 10 kilograms= 10,000 grams when

used for weights and measures When used in the

con-text of computer data, more commonly it is

capital-ized, as in Kbps (kilobits per second), and represents

1024 See k, K

kilocharacter One thousand characters See

kilosegment

kilosegment One thousand segments, with each

seg-ment consisting of up to 64 characters It is used as a

billing measure in some systems, such as X.25

kilovolt-ampere kVA Aunit ofapparent power This

is a general measure of power consumption for

nonresistive devices such as certain types oflighting

and computer components

kilowatt kW An SI unit ofpower required to do work

at the rate of 1000 joules per second See joule,

kilo-watt-hour, watt

kilowatt-hour kW-hr A unit of the energy used to

perform work as measured over a I-hour unit of time

One thousand watt-hours, or 3.6 million joules This

has practical applications as a description of the

effi-ciency of different types of fuel, which can be

ex-pressed and compared in terms of kilowatt-hours

kinescope I Acathode-ray tube (CRT) in which elec-trical signals, as from a television receiver, are dis-played to a screen 2 An early term for amotion

pic-ture, and probably the inspiration for the term cinemascope In Britain, the term cinematograph was used to indicate a motion picture or motion picture camera

kinetograph A device patented in 1889 by Thomas Edison for photographing motion picture sequences See kinetoscope

kinetoscope A device patented in 1893 by Thomas Edison for viewing a sequence of pictures, based upon the work of earlier experimenters going back

as far as 1883 The loop of film images was illumi-nated from behind and viewed through a rapidly ro-tating shutter, thus creating a smallmotion picture

film See kinetograph

King, Jan The young engineer who coordinated a number of significant amateur radio telecommunica-tions satellite projects, starting with Australis-OS-CAR 5 and continuing with the AMSAT satellites King has written articles and technical reports on some of these activities, many of them for the QST journal See AMSAT, OSCAR

Kingsbury Commitment An important event on December 13, 1913 in which the U.S Attorney Gen-eral, James McReynolds, informed AT&T of viola-tions of the Sherman Antitrust Act of 1890 AT&T voluntarily gave up controlling interest in the West-ern Union Telegraph Company, and agreed tostop buying up the independent telephone companies without first obtaining approval from the Interstate Commerce Commission (ICC) AT&T further agreed

to provide independent phone companies with access

to the long-distance network

The Kingsbury Commitment derives its name from NathanC.Kingsbury, the AT&T vice president who was appointed by Theodore Vail to correspond with the Attorney General.Itis sometimes colloquially called the Kingsbury compromise See Modified Fi-nal Judgment

Kirchhoff, Gustav Robert (1824-1887) A German physicist who conducted pioneer work in spectros-copy and followed up on Ohm's work by providing further information and a more advanced theory of the flow of electricity through conductors He also made adjustments to Huygen and Fresnel's descrip-tion ofthe behavior ofwavefronts by introducing the obliquity factor See Huygen's integral, Kirchhoff's laws

Kirchhoff's laws Laws for the flow of current first described in 1848 by G.R Kirchhoff:

I The current flowing to a given point (node)

in a circuit is equalto the current flowing away from that point

2 Inany closed path in a circuit, the algebraic sum of the voltage drops equals the algebraic sum of the eleclromotive forces in that path KIS See Knowbot Information Service

KISS Keep It Simple Stupid Atongue-in-cheek, but all-too-relevant design and management philosophy

whose success is, in part, due to the relative absence

of bells and whistles The early Apple Macintosh

computers held to this philosophy as well,

develop-ing a one-button mouse when many others were

us-ing mice with two or three buttons, and maintainus-ing

standards for the operating system that enabled new

users to quickly figure out how to use it

KISS methodA system-independent architecture

related to information systems modeling, which is

described in terms ofobject-oriented concepts by its

author, Gerald Kristen KISS concepts are presented

in a series of stages, and the model and presentation

are sufficiently different from other works in the field

of object-oriented(00)programming that it has not

excited a lot ofinterest in the00programmers'

com-munity

KittyhawkAline ofvery small-sized (less than 2 x 3

in.) 20- and 40-MByte, 44-pin IDE hard drives

dis-tributed by Hewlett Packard for use in palmtop text

and PDA computers

KLAS-TVAnearly commercial adopter of

all-digi-tal advanced television (ATV) technology KLAS-TV

is a Las Vegas CBC affiliated owned by Landmark

Communications, Inc., a privately held media

com-pany Advanced television technologies were

re-searched in the early 1990s by the Advisory

Com-mittee on Advanced Television Service (ACATS),

with digital technologies coming in late in the

pro-cess, but then becoming the central focus ofACATS

evaluations The ACATS Final Report was presented

in 1995, paving the way for broadcast stations in

North America to begin to implement higher quality,

standardized digital television services KLAS-TV

was the first broadcaster in the Las Vegas region to

offer end-to-end digital technology and

transmis-sions, in April 2000 Prior to offering digital

sub-scriber services, KLAS-TV delivered digital

pro-gramming 2 years in a row to the National

Associa-tion of Broadcasters (NAB) annual trade show at a

Las Vegas convention center, establishing themselves

as one of the pioneer commercial providers of

all-digital broadcast programming

System components for KLAS-TV equipment were

developed and provided by Harris Broadcast

Com-munications, who also provided the radio frequency

Test Bed used in the ACATS evaluation ofprototype

digital broadcast systems See Advisory Committee

on Advanced Television Service, Harris Broadcast

Communications

Kleinrock, Leonard(1934- ) In 1976, authored

Queueing Systems Volume II - Computer

ac-ceptance ofpacket-switching technology

Kleist, Ewald Christian vonSee von Kleist, Ewald

Christian

kludge, kluge Patchwork, improvised, or makeshift

hardware or software, which can result from (1) time

or material constraints, (2) sloppy workmanship, lack

of foresight, (3) communication problems between

decision-makers and implementors, or (4) staff

changes or design changes during a projecl

with software that tends to be sluggish from lack of structure and optimization, while well-conceived, but time-constrained proj ects are more often called

"quick-and-dirty." Even well-begun projects can be-come kludgy after awhile, in which case engineers will generally advise, "Time for a ground-up rewrite!"

Klystron, klystronFrom the Greek "klyzo." Ahigh-vacuum electron tube that uses electric fields to cause the "bunching" ofelectrons into a well-focused beam

The beam's kinetic energy is converted and ampli-fied into ultra-high frequency radio waves (micro-waves) Klystron was established as a trademark and

as such is spelled with a capital letter, though the term

is now also used generically for the historic line of Klystron tubes Klystrons were used widely as oscil-lators and applied to radar transmitters until they were superseded for some applications by cavity magne-trons Current commercial tubes are long-life, reli-able, remanufacturable components

Klystron Electron-Tube Inventors '

Top: The Klystron and its inventors at Stanford in

1939 Clockwisefrom the left are Sigurd Varian, David Webster, William Hansen, John Woodyard (a gradu-ate student), and Russell Varian Small Klystrons were used for radar, navigation, and communications ap-plications [Copyright 1939 and 1951 Stanford News Service archives; used with permission.]

The Klystron evolved from pioneer versions of the magnetron which were developed in the 1920s

Russell H Varian and Sigurd F Varian respectively designed and constructed the first Klystron prototype

at Stanford, beginning in 1937, in collaboration with William Hansen The July 1937 notes of Russell Varian describe the "Rumbatron Oscillator or Ampli-fier" and input from William Hansen regarding a

"spherical rumbatron with one core reaching to the center." The rumbatron moniker was based upon Hansen's previous work on cavity resonators The Varians combined this with principles of velocity modulation to create the Klystron, publicly an-nounced in 1939