Nicholas I. Benimoff

Michael J. Burns

Multimedia User Interfaces forTelecommunications Products and Services

The emergence ofmultimedia systems, which incorporate media types suchas text, graphics, audio, video, andanimation, has greatpotential to changehow people interact with systems andwith each other. As multimedia tech­nologies andtheir applications in telecommunications products and servicesevolve, some critical human factors challenges in designing these systemsare emerging. This paper describes how the use ofnew multimedia technol­ogies, complemented bythe proper application ofhuman factors design prin­ciples, canenhance the usability ofAT&T products and services. Examplesofthree types ofapplications - multimedia-based training, multimedia­based performance support, andmultimedia conferencing - highlight chal­lenges specific to the design ofmultimedia user interfaces.Introduction

"Multimedia is amajorpartofAT&Ts future, andwewill workveryhardtomake thathappen. " 1

-Robert E.Allen, AT&T Chairman

In the past severaldecades, telecommunica­tions and computertechnologies haveexpanded at a far greater rate than manycouldhaveimagined. Evolving telecommuni­cations capabilities haveled to changes inwhen,where,why, and howpeople communi­cate.Advances in computercapabilities havechanged manyaspectsofour workand per­sonallives,and will continue to do so.We areon the verge ofa revolution in whichtheboundaries oftelecommunications, comput­ing,publishing, entertainment, consumerelectronics, and information accessarebecoming blurred.A"mega-industry" is beingcreated,driven by the emergenceofnewtechnologies, the most important ofwhichismultimedia.

Multimedia systems incorporate avariety ofmediatypes, including voice, image,music, text, animation and graphics, real-timeand stored video, andfacsimiles. Atleast twoschools ofthought exist concerning thedefinition ofmultimedia systems.f Somebelieve that the inclusion ofmultiple media

types is enough to categorize a systemas"multimedia." In this paper, however, wearereferringto multimedia telecommunicationsproductsand servicesthat combine some orallofthese media in an interactive computingapplication.

This paper describesmultimedia sys­tems in which the user actively controlscom­munications. Specifically, the level ofcontrolis critical. Users ofmultimedia systemsshouldbe ableto do morethan start and stopan application. Their actions shouldtriggerdifferent systemresponses, based on a hostoffactors (e.g., prioruser actions or currentsystemcontext). The information that the sys­tem presents, and eventhe mediathroughwhichit is presented,will be influenced bythese factors.

Multimedia technologies and theirapplications in telecommunications productsand servicesare just beginning to evolve.Clearly, these technologies will changetheway people interactwithcomputer systems.Muchas graphical user interfaces revolution­izedhuman-computer interaction in the1980s, the maturation ofmultimedia technolo­gies will fundamentally alter human-computerinteraction paradigms in the 1990s, andbeyond. There will be more emphasis ondeveloping systemswithuser interfaces thatare interactive, dynamic, andengaging.

42 AT&T TECHNICALJOURNAL• MAY/JUNE 1993

In addition to changing howpeople interactwithcomputer systems, multimedia technologies maychangethe way people interactwitheach other.Video telephonyhas already hit the marketplace withproductsthat arecertain to affect person-to-person communication.' Onagranderscale,multimedia conferencing and multimediacomputer-supported cooperative work (cscw) systemsundoubtedly will change many meeting, workgroup,edu­cational, and other communication activities. (See Panellfor definitions ofabbreviations, acronyms, and terms.)

This paperfocuses on hownewmultimedia tech­nologies, combined withthe properapplication ofhumanfactors designprinciples, can improve AT&T's productsand services. We discussusability as it applies tomultimedia-based productsand services, and the designchallenges presentedby multimedia technologies. Exam­ples are culled from multimedia-based training, perfor­mance support, and conferencing.

Multimedia and UsabilityBrianShackel defines usability as "the capability

inhumanfunctional terms to be used easily (toa speci­fied level ofsubjective assessment) and effectively (toaspecified level ofperformance) by the specified range ofusers, given specified training and user support, to fulfillthe specified range oftasks,within the specified range ofenvironmental scenarios."! For a systemto be usable, itsusers shouldbe ableto:- Easily learn howto operate the system- Efficiently complete the task(s) they are performing

with the system- Interactwiththe systemwithout making errors- Enjoy interacting withthe system.

These goals apply to the user interface for anycomputer-based system, whether or not it employs multi­media technologies. We expectthat,whenused prop­erly, multimedia technologies will enhancethe usabilityofmany productsand services. Multimedia systemsshould create an intuitive environment that minimizestheeffort required to learn and use the system. Somestudies ofinteractive multimedia-based training suggestthatlearning occursfaster and that learnedmaterial isunderstood better and rememberedlongerthan it is withclassroom instruction.f

People process information usingtheir fivesenses, especially sight andhearingfor communicationtasks. Certain typesofinformation are better commu-

Panel 1. Abbreviations, Acronyms, and Terms

ac- alternating currentAM - amplitude modulationCAD/CAM - computer-aided design/computer-aided

manufacturingCD - compact diskCPS - Concept Presentation SystemCSCW - computer-supported cooperative workde- directcurrentEPS - electronic performance supportFM - frequency modulationNOET - AT&T Network Operations Education and

TrainingNSD - AT&T Network Systems DivisionVCR - video-cassette recorder

nicated through one medium than another. For example,full-motion video does a goodjobofdemonstrating com­plexmechanical procedures." In addition, multimedia­based products andservices, such as multimedia-basedcscw applications, can helpworkersbe moreefficient ina variety oftasks, including meetings, document prepara­tion, physical design, computer-aided design/computer­aidedmanufacturing (CAD/CAM), etc.,especially forthose inwidely separated locations.

Multimedia technologies often enhanceusabilityby supporting various inputdevices (e.g., voice, pens)that allow users to interactmore naturally with systems.Finally, multimedia systemspromise to be moreengag­ing,morefun to use.? Multimedia presentation canincreasethe expressiveness of, and the audience's senseofinvolvement with, the information presented.8

Although multimedia systemsmaybe "richer"than their single-media counterparts, they do not neces­sarily increaseusability. Studies ofmultimedia telecon­ferencing haveshown that the usefulness ofvideodependson the specific tasks that users perform duringthe call.9,10 Krautet al.8 suggestthat interaction with orthrough multimedia systemscreates a newtype ofcom­munication. The mostusablemultimedia systemsarethose whoseuser interfaces are designed consistentlywith, and take advantage of, this premise.

If the benefits ofmultimedia-based systems areto be fully realized, theymust be tailored to the needs,capabilities, andlimitations ofusers. Some critical chal­lenges in building these systemsrelateto humanfactors,becausetheyhavethe potential to changethe fundamen­tal natureofhumaninteraction with systemsandwithother people usingthese systems. Although multimediatechnologies clearly offer benefits, a variety ofusabilityissues should alsobe considered.

Multimedia Products and Services. Analysts in thetelecommunications industry agree that multimedia

AT&TTECHNICALJOURNAL. MAY/JUNE1993 43

Figure 1. Sample

screen from theAdvantage SM multi­

media training sys­tem. The presentationwindow, at the left,displays photographs,graphics, animation,and video. The textwindow, at the right,presents text thatcomplements the

audio narration. Func­tion buttons andother controls are atthe bottom of thescreen.

capabilities will be a cornerstone oftelecommunicationsnetwork and productdevelopment in the next decade. 11AT&T is committed to offering products and servicesthat allow people to communicate efficiently and expres­sively. Anopportunity now existsto provide useful newcapabilities basedon multimedia technologies; such asmultimedia conferencing; interactive information ser­vices; entertainment services; andeducation, training,and performance support.

For instance, the Rapport multimedia confer­encing system.P developed at AT&T Bell Laboratories,allows people inwidely separated locations to sharevoice, video, data, andother applications in real-time.AT&T is also cooperating with Pacific Bell, CaliforniaStateUniversity at Chico, and the Chico public schoolsystem to offer distance education, which allows studentsto "attend" a coursefrom a remotelocation usinga multi­media workstation. Eachstudentcanenroll in individuallypaced coursesand attendat his or her preferred timeandplace. The NCR 3331 Multimedia Learning Station deliversmultimedia-based education coursesinbusiness, retail,andmanufacturing environments. The AVP4000 video-

44 AT&TTECHNICALJOURNAL.MAY/JUNE1993

compression chipset, produced byAT&T Microelectron­ics,makespossible reliable andcost-efficient storageandtransmission ofmultimedia data. TheAT&T/EO Per­sonal Communicator 440 allows users to combinemultiple input (e.g., touchscreen,handwriting) andout­put media (e.g., audio, text,fax) to perform a wide vari­ety oftasks (e.g., recordnotes, accessbankrecords,place a phonecall). Even the AT&T VideoPhone 2500,TMthe world's first colorvideo telephone that operates overconventional copper telephone lines, is basedon multi­media technologies.

AT&T is incorporating humanfactors principlesintoits multimedia products and services to ensure theirusability. The sections that follow focus on examplesdrawn from multimedia-based training, performance sup­port,and conferencing. These examples illustrate thepotential that multimedia technologies haveto enhancethe usability ofmanyexisting products and services andtoengenderentirely new classesofproducts and services.

Multimedia-based training. Multimedia technologiesare revolutionizing howtraining simulations are used.Until recently, complex simulations wereprohibitively

Figure 2. Sample screen from the Rapport multi­media conferencing system. Individual atten­dees, conference status, and conference con­trols are displayed along the top. Two separate,shared applications - in this figure, a textdocument and a stored videotape segment ­are open for all attendees to view and manipu­late at their own workstations.

"ll'-J'ilAI"TfiiA1'/tiIu~~ l'h~ .1.",,,

~bIidI.~""'_<'4m,,,,·>I"·"""IJ/.'~ r",,~ "'-"i';::-,..:..~,!,Z~ :,':: ~.'.~:~ .~>·~;··v ~ •..fi/ ......~.~ P'''VO''', "~.::,:~~ :;;':," REf II",..,..,~.fb.rpptII1"..., r~ ....t.='~. ,,",;)-.::::, ': ::'.« »~~ <~I~:~

LI=l:~_'I~::. ""~",,,>r! .,. ,~<:~~~' II >'::~=.-~_.~... "':~l~:~-:'~:IM' ~~'.~~fl. "'II . ....'rN.' l , .,.., ."Il't'IO'l 'II

" .......... "w.••l1 '"''TIM''''' ,: •.",•.,\0...,.,,....... r', "4".,~. 1'00:''''11,[

.".,.. ;><>''t, ... ,(....",.,.1".'".·.I'''&JILf ;1l"''l''!'L:' 'llM"('I"'I(1': .. ~,_.~ '''' t-."

Ie""';- "'." "":<, r.. ·f;". ...." .~ ~,I ..nr :nr'lb U'ltl ...." •. -ce ,,/ •• ,Jt.',.,..

"'ulT;.r "I. 1IIl~·I~ &l ;1· ....~J(""f\\: ••. ,1 •

r,;',""·.aI~ f"""".,I ,. ,.~ -jocr ,,~. ,....1.

il!&Olh"'!!"':!eterfO!w:MI _."h .it ..•.. "~. 11:··. I! .. j I' I

!

'i-..J_ .._ ..~~~.==-.'"-_'"

d

l·idl.S1••. ".'.'.. Supporting Mulll·Phase (;",u~~urS tNt....~""l!~, .... ·t ~

,l!!lI~

If:d!2J

•i.-..J!J-.~,jd:.9.1'1£'.9.l.Jo:J.:Jr;:

expensive to develop and deliver. In only a few fields,suchas aviation and nuclearpower (where a single mis­take in the realworld mightbe catastrophic), has theexpense ofsimulations been justified. Oneofthe mostimportant benefits ofmultimedia technologies, therefore,isits ability to deliver low-cost, medium-fidelity simula­tions on desktop computers. While these desktop simula­tions maynotbe as realistic as a Boeing 747 flight simu­lator, they are realistic enoughto give studentsthe free­dom to experiment and to practice individual steps in asequence repeatedly untiltheyget them right.

Many jobsperformed byAT&T technicians lendthemselves naturally to training by simulation. For exam­ple, small, unattended buildings, called regen huts, arelocated approximately every30miles along a lightguideroute to regenerate the fiber-optic signal. Ateach regenhut, AT&T technicians perform an annual power reviewthat involves 23major steps that must be completed in aspecific order. Because the power review is performedonly oncea year per regen hut, evenexperienced techni­cians mayrun intoproblems. During the procedure, thetechnician must transferthe power in the regen hut fromnormal commercial ac power to backup de power. Thisprocedure puts technicians under stress, becausea mis­take canresult in the failure ofa segmentofthe fiber­optic network. Bypracticing with a simulation ofthe

annual power review before performing it, the techniciancanbecome familiar with each step in the procedure andhowthese steps fit together.

The AT&T Network Systems Division/NetworkOperations Education andTraining (NSD/NOE1) PowerTechnology Institute is producing a hardware andsoft­ware platform, called the Advantage'" multimedia train­ing system, to develop and deliver multimedia training.The firstcourseprovides multimedia-based demonstra­tions, practice simulations, and tests forthe annualpower review ofa regen hut. Figure 1 shows a screenfrom the annual power review courseon the Advantagemultimedia training system. FutureAdvantage courseswill teach studentsaboutpower-related equipment (suchas batteries, rectifiers, andtools) andother technologies(suchas alarms, outside plant, andlightguide). Photo­graphic images, audio, andanimation allplay centralrolesin the Advantage instruction and simulations.

Multimedia-based performance support. Trainingensures that workers have achieved a minimum level ofproficiency before attempting to perform a jobin the realworld. Butmany instructional technologists are adoptingthe view that training alone may not enable workers todo their jobseffectively and efficiently. Electronic perfor­mance support (EPS) integrates training, documentation,and on-line helpand delivers it to the workeras needed

AT&TTECHNICALJOURNAL.MAY/JUNE1993 45

at the worksite. It emphasizes performance, rather thanlearning, and is delivered to the workerwith minimalinterruption ofthe normal jobflow.

EPS systemsdo not necessarily include multi­media capabilities, but designers are finding that thesecapabilities maketheir systems moreeffective. Severalversions ofthe Concept Presentation System (cps),developed inAT&T Bell Laboratories, have supportedtechnicians who perform network management and pro­visioning activities or who diagnose and repairtroublesin switches.

cps functions with applications the workernor­mally uses to do the job. In the 5ESS® switch version, theworkercan"toggle" to cps bypressinga single key onhis or her workstation. The user receives instructionsfrom cps at several different levels, ranging from an over­view ofthe current procedure, through detailed step-by­step instructions, to a listing ofvalid entriesfor a specificfield on a recently changedscreen in the on-line system.cps presentsinformation usingtext,graphics, andmotion video, with accompanying narration. Assoonasthe user gets the information neededfrom cps, he or shecan toggle backto the on-line system, which remains inthe samestate it wasin before the user leftit to accesscPS. If moreperformance supportis requiredlater,theuser canreturn to cps.

Multimedia conferencing. Multimedia conferencingsystems, an important application ofmultimedia tech­nologies within AT&T, allow individuals at widely sepa­rated locations to perform meeting-related tasks andother activities as iftheywerein the sameroom. Theycan see one another, talkprivately with someone, pre­sentviewgraphs, share images, write on a blackboard,pointto itemson the blackboard, etc. Figure 2 showsa sample screenfor one such system- the Rapportmultimedia conferencing system- developed at AT&TBell Laboratories.

Multimedia conferencing provides advantagesovermore limited forms ofconferencing. For instance,by usingtechnologies that enable participants to see andhear one anotherat the sametime, and to use network­basedblackboards and other communication devices,multimedia conferences attemptto restore the "natural­ness"ofin-person communication to individuals commu­nicating electronically. Moreover, multimedia conferenc­ingcanincrease the productivity and efficiency ofmeet­ings. Participants havethe flexibility to presentor manip­ulate information usingwhichever media best suits their

46 AT&TTECHNICALJOURNAL.MAY/JUNE1993

needs. Theyhaveaccessto information sources, suchasinternal corporate databases, external public resourceslikethe Library ofCongress, and so on.Multimedia­basedmeetings can also produce tangible savings, suchas the costand timeassociated with travel.

Multimedia User Interface IssuesDesigning a successful multimedia user interface

is a challenging task,because muchofwhatpeople do"naturally" ineveryday life - seeingandunderstandingobjects andgestures, understanding eachother's speech,etc.- is a tremendous challenge forthe field ofcomput­ing.13Agooduser interface foran interactive applicationmustfit the user's motorskills.l! problem-solving strate­gies,15 andcognitive organization.l'' Userinterfacedesign for a single-media application is difficult; the pros­pectofdesigning for multiple media andthe need to inte­grate different typesofmedia makethe task ofdesigninguser interfaces evenharder.

Aswediscussed earlier, the application ofmulti­media technologies createsexciting opportunities fornewproducts and services. Butthesenew opportunitiesalso presentchallenges to the human factors specialist.These challenges, listedinTableI, are detailed in thesections that follow.

Appropriate Use of Media. Whattasks are bestservedbythe various media now at our disposal? Whatare the development and delivery cost tradeoffs ofdiffer­ent media types? Can weidentify the different typesofinformation delivery tasks andcommunication situationsandrecommend appropriate media?

User Control over Multimedia Environment. Towhatextent should users be allowed to customize theirown multimedia environments? Duringa multimediaconference, for example, should users be able to reposi­tionwindows that display other attendees? If these win­dows are moved, will allattendeesknow to whom eachofthem is speaking?

Information Navigation. How should informationbe organized in a multimedia systemto makeit easytouse? How can systemdesigners help users find theinformation they need? Donavigation devices usedinhypertext systems, such as information structuremaps,guides, default paths, andbacktracking, benefit multi­media systems?

Control of Time-Based Information. Bywhatmeansshould users control the presentation andflow oftime­basedinformation in the system? Areuser interface

Table I. Multimedia User Interface Challenges and Problems

Human factorschallenges

Appropriate use ofmedia

Usercontrol overmultimedia environment

Information navigation

Control oftime-based information

Tools formultimedia authors

Media fidelity

Social psychological andhumanbehavioral issuesUseracceptance ofmultimedia-based productsandservices

Typical problem

Which applications requirefull-motion video,still-image graphics, or animation?Should usersbe allowed to customize howmultimedia objects are arranged ontheir screens?Can users access the nextpiece ofinformation ina database?Is there a universal set ofon-screencontrols to start,stop, pause, resume,replay, etc.?How canmultimedia authorsdecreasethe timeit takesto.script, edit,andintegrate media objectsforan application?Whatare the minimal audio andvideorequirements forvarious applications?Which characteristics offace-to-face meetingsshould multimedia conferencing include? ...How cannon-computer-literate peoplebenefit from multimedia productsand services?

Problem-solvingstrategies

Iterative rapid prototypirtg

•Usability testing

•User-centered design

•Knowledge'gatheredfrom

many disciplines

metaphors, such as compactdisk (CD) audiocontrolsorvideo-cassette recorder (VCR) controls, the best ones? Istherea "universal" set ofcontrols, or do different tasksdemand different controls? What tradeoffs in controlfea­turesare necessary because offunctions not supportedbythe current levelofmultimedia technologies? Andmore generally, in the absence ofindustry-wide stan­dards, howcan we create user interfaces that are consis­tentin importantaspects withothers in the industry?

Tools for Multimedia Authors. What help can beprovided to the people whoare developing multimediasystems? What toolsfor ideagenerationand scriptwrit­ing can help them be more creative and productive? Arethere ways to shorten the time required to develop andedit mediaelements (individual graphics files, audiofiles, etc.)? How can mediaelementsbe most efficientlyassembled and integrated into a coherent application?

Media Fidelity. What types ofaudioand videoquality needs do users have,and howdo these needschange for different applications? Is en-quality audio

required, or would frequency modulated (FM) quality, oreven amplitude modulated (AM) quality, suffice? Is full­motion video, or evenfull-screen video, necessary? Whatlevelsofcolorrendition, contrast, imageresolution, andscreen refresh rate are necessary? What degree ofaudio-video asynchrony is perceptible, and at whatpointdoes it hinder usability? Ifa window in a multimedia con­ferencing environment provides person-to-person eyecontact, howcan we ensure that allimportant nonverbalinformation (e.g., head-shaking, facial expressions, etc.)is communicated while using as littlescreen spaceaspossible? Howimportantis full-duplex audio, and howdoes it affect systemusability?

Social Psychological and Human Behavioral Issues.

Howdo face-to-face meetingsdiffer fromelectronicallymediatedones? Whatare the importantqualities andby-products ofboth face-to-face and electronically medi­ated meetings, and howcan multimedia conferencingsystemsbe designed to maximize their advantages?What are the importantnonverbal feedbackmechanisms

AT&TTECHNICALJOURNAL. MAY/JUNE1993 47

people use in conversation? Howis the character ofameetingaffected by its multimedia nature? What assump­tions do participants make aboutwhat other participantsare doingand seeing, and what are the effects of theseassumptions? Howcan multimedia conferencing improvegroup dynamics and decision-making processes?

In summary, it is not sufficient merelyto providesystemswithmultimedia capabilities. Instead,we mustunderstandhowand whyindividuals will be using thesystem,and we must design the user interface accord­ingly, withthe set ofinteractiontechniques best suitedto the givenmedia.

Potential SolutionsAs the previoussection illustrates, there are

manyuser interface design issues that relate specificallyto multimedia systems. However, the prospectsfordesigningusable multimedia systems are not as over­whelming as this list might imply. Someofwhatweknowaboutgood design for graphicaluser interfaces can beapplied to multimedia user interfaces. Information struc­ture maps, guides, etc., shouldhelp the user navigatethrough information, whether text-based or multimediain nature.Sometimes, design decisions can be modeledon well-known user interfacemetaphors. For example,users seem to have littleproblemlearning,understand­ing,and controlling on-screen motionvideousing adesign that resembles a VCR remote controldevice.

We can also use results gathered fromwell-run empirical studies. For instance, increasingthe audioquality ofa multimedia phone callhas been showntohave a positive effecton users' perceptionsofthe call'svideo. 17 Phenomenasuch as this can be used to formu­late design decisionsthat improve usability whilemini­mizing resources.

Solutions for unsolved multimedia user interfacedesign issues will comefrom manysources. Methodolo­gies such as iterative rapidprototyping, usability testing,and user-centereddesign that havebeen provensuccess­ful in systems designwill continueto be critically impor­tant.18,19 Iterative rapidprototyping refers to buildingamodelofthe user interface, beforeformal developmentofthe system, that looks and behaves as the systemwillwhen it is completed. This prototype shows a system'sfunctionality and user interfaceand is iteratively updatedto reflectuser and projectteam feedback, new systemrequirements,etc. Usability testing, in a specially

48 AT&TTECHNICALJOURNAL.MAY/JUNE1993

designedlaboratory or, sometimes, at the user's worksite, can uncoverdesign flaws that projectteam mem­bers might miss. Basedon what is learned duringthisphase, design changes are made in the next iteration ofthe prototype, ensuring that the final system meets userneeds in an efficient, pleasingmanner. Iterative rapidprototyping and usability testing,whichworkhand-in­hand to improve the design ofanyuser interface, arecore methodologies ofuser-centered design.

Knowledge gathered fromother fields, suchas cognitive and social psychology, computerscience,graphicarts, broadcasting, and instructional technology,will alsohelp solve future problemsin multimedia userinterface design. Successful multimedia systemdevelop­ment requires diversity amongprojectteam members.The idealprojectdevelopment team includes memberswhohave most, if not all, of these skills.

ConclusionsIn the future, multimedia technologies will affect

the ways in whichpeopleinteractwithsystemsand witheach other.The inevitable development ofpowerfulmultimedia productsand services, and the broadbandnetworkinfrastructure to support them, will make multi­mediacommunications as ubiquitous as today'stele­phone or personalcomputer. John Sculley, Chairman ofApple Computer, Inc.,foresees a convergence ofprevi­ouslydiverse industries- computing, consumer elec­tronics, communications, broadcasting, and publishing- all integratedin hand-held devices that will be ubiqui­tous.20 Nicholas Negroponte, founderand directorof theMediaLaboratory at the MassachusettsInstituteofTechnology, envisions a future in whichmachineswillsee, hear, talk,and, in a sense, think, allto "know" andserve their human masters.s' The speedwithwhichthisfuture is realized depends on severalfactors, includingthe continueddevelopment ofbetter hardware (e.g.,computers, chips, transport equipment) and software(e.g., video compression and decompression algorithms,development tools). To be successful and ubiquitous,however, these productsand servicesmust be designedto fit users' needs. Howclosewe cometo achieving thiswill directly affect our ability to realize this vision.

AcknowledgmentsWe thank DougBrems,Jim Farber, BruceFetz,

Susan Fussell, KenRosen, and Bill Whittenfor

thoughtful reviews ofearlierdrafts ofthis manuscriptand forvaluable discussions on the rolesanduses ofmultimedia technologies. We also thank the AT&TNSD/NaETPower Technology Institute forpermissiontoinclude a screenfrom the Advantage multimedia train­ingsystem, shown in Figure1. Finally, wethank the Inte­grated Computer/Communication Systems ResearchDepartment ofAT&T Bell Laboratories forpermission toinclude the Rapport multimedia conferencing systemscreen shown in Figure2.

References1. A Ramirez, "The Vision ofRobertE. Allen," The New York Times,

January3,1993,Section 3,p. 6.2. T. Nolle, "Choosing a platform formultimedia," Datapro Multi­

media Solutions, McGraw Hill, Inc.,NewYork, June 1992, p. 1030.3. ]. S.Angiolillo, H.E. Blanchard, and E.W.Israelski, ''Video Tele­

phony," AT&TTechnical journal, Vol. 72,No.3, May/June 1993,pp.7-20.

4. B.Shackel, "The conceptofusability," Visual Display Terminals:Usability Issues andHealth Concerns, J. Bennettet al. (eds.),Prentice-Hall, Englewood Cliffs, NewJersey, 1984, pp. 45-87.

5. G.L. Adams, ''Whyinteractive?," Multimedia andVideodisc Moni­tor, Vol. 10,No.3, 1992, p. 20.

6. M.Webster,"Electronic Books," Multimedia Computing: CaseStudies from MITProject Athena, M.E. Hodgesand R. M.Sasnett(eds.),Addison-Wesley PublishingCompany, Inc.,Reading, Mas­sachusetts, 1993, pp. 139-150.

7. N.Negroponte, "Newqualitiesofcomputerinteractions," Proceed­ings oftheIEEEInternational Conference onCybernetics andSoci­ety, Tokyo-Kyoto, Japan,November 3-7, 1978, pp. 1402-1411.

8. R. Kraut, C. Egido, and]. Galegher, "Patterns ofcontactand com­munication in scientific research collaborations," Intellectual Team­work: Social andTechnological Foundations ofCooperative Work,Lawrence ErlbaumAssociates, Hillsdale, NewJersey, 1990,pp.149-171.

9. E. Williams, "Experimental comparisons offace-to-face and medi­ated communication: A review," Psychological Bulletin, Vol. 84,No.5, 1977, pp. 963-976.

10. C.Egido, "Teleconferencing as a technologyto supportcoopera­tivework: Its possibilities and limitations," Intellectual Teamwork:Social and Technological Foundations ofCooperative Work, J.Galegher, R. Kraut,and C.Egido (eds.),Lawrence ErlbaumAssoci­ates, Hillsdale, NewJersey, 1990, pp. 351-372.

11. ]. S. Mayo, "The Future ofTelecommunications," AT&TTechnol­ogy, Vol. 7, No.1, 1992, pp. 2-7.

12. S. R. Ahuja, J. R. Ensor,and S. E. Lucco, "Acomparison ofapplica­tionsharing mechanismsin real-time desktopconferencing sys­tems," Conference on Office Information Systems (SIGOIS Bulletin),Cambridge, Massachusetts, April 25-27, 1990, Vol. 11,Issues 2and3,pp. 238-248.

13. J. Grudin, "CSCW introduction," Communications ofthe ACM,Vol. 34,No. 12,1991, pp.30-35.

14. W.Buxton, "There's more to interaction than meets the eye:Someissues in manualinput," User Centered System Design,D.A.Norman and S.W.Draper (eds.),Lawrence Erlbaum Associ­ates, Hillsdale, NewJersey, 1986, pp.319-338.

15. ]. S. Brown, "Fromcognitive to socialergonomics and beyond,"User Centered System Design, D.A Normanand S.W. Draper(eds.),Lawrence Erlbaum Associates, Hillsdale, NewJersey, 1986,pp.457-486.

16. D.A Norman, "Cognitive engineering," User Centered SystemDesign, D.A Normanand S.W. Draper (eds.),Lawrence ErlbaumAssociates, Hillsdale, NewJersey, 1986, pp.31-61.

17. W.R. Neuman, A N. Crigler, and V.M. Bove, "Television Soundand Viewer Perceptions," Proceedingsofthe Joint IEEE/AudioEngineering Society Meetings, February1,1991, Detroit, Michigan.

18. M. C.Dayand S.]. Boyce, "Humanfactorsin human-computer sys­tems design," Advances in Computers, M.Yovits (ed.) ,Vol. 36,Aca­demicPress, Inc.,San Diego, California, 1993, pp.333-430.

19. R. E. Opaluch and Y. C.Tsao, 1993 "TenWaysto Improve UsabilityEngineering: Designing User Interfacesfor Ease ofUse," AT&TTechnicaljournal, Vol. 72,No.3, May/June 1993, pp.75-88.

20. J. Markoff, 1992 "Beyond the PC:Apple's promisedland," The NewYork Times, November 15,1992, Section 3,p. 1.

21. H. Brody, "Machine dreams:Aninterview withNicholas Negro­ponte," Technology Review, Vol. 95,No.1, 1992, pp. 33-40.

(Manuscript approved june 1993)

Nicholas I. Benimoff is a member of technical staff in theUser Interface Planning and Design Department at AT&T BellLaboratories in Holmdel, New Jersey, where he designs andevaluates user interfaces for multimedia conferencing sys­tems. Mr. Benimoff received an AB. from Clark University,Worcester, Massachusetts, and an M.A and Ph.D. fromColumbia University, New York, all in experimental psychol­ogy. He joined AT&T in 1985.Michael J. Burns is a member of technical staff in the UserInterface Planning and Design Department at AT&T BellLaboratories in Holmdel, New Jersey. He designs anddevelops multimedia- and hypermedia-based training and per­formance support systems. Mr. Burns received a B.A fromWashington & Lee University, Lexington, Virginia, and an M.A.and Ph.D. from the University of California, Los Angeles, all inpsychology. Mr. Burns joined AT&T in 1981, left in 1985 towork at the National Aeronautics and Space Administration(NASA) Johnson Space Center, and rejoined AT&T in 1986.

AT&TTECHNICALJOURNAL.MAY/JUNE1993 49