Promoting accessibility by using metadata in the framework of a semantic-web driven CMS

·Abs ac : Fe nando Díaz del Río Robo ics and Compu e Technology o Rehabili a ion Lab. Uni e si y o Se ille (SPAIN) Tel: +34 95 4556144 Fax:+ 34 95 4556449 [email p o ec ed] An ón Ci i Robo ics and Compu e Technology o Rehabili a ion Lab. Uni e si y o Se ille (SPAIN) Tel: +34 95 4556470 Fax:+ 34 95 4556449 [email p o ec ed] Juan An onio P ie o Xime iX ne wo k hough s SL Tel: +34 91 3645475 [email p o ec ed] Web con en accessibili y o impai ed people has been mainly add essed by he Web Con en Accessibili y Guidelines (WCAG) de eloped by he Web Accessibili y Ini ia i e (WAI) o he W3C Conso ium. Those guidelines ha e p o ed o be good diagnos ic means o es ing accessibili y o di e en ypes o impai men s, as well as o guiding he de elopmen o accessible con en . A u he s ep would be o p omo e disco e y o ma e ial ha ing app op ia e accessibili y suppo , as well as he adjus men o con ol and display o esou ces o mee use accessibili y needs and p e e ences [5]. The las wo challenges ha e been add essed by he IMS Global Lea ning Conso ium in he IMS-AccessFo All (ACCMD) and he IMS Lea ne In o ma ion P o ile (ACCLIP) speci ica ions. Al hough IMS has app oached bo h goals in a lea ning amewo k, bo h accessibili y speci ica ions pay a special a en ion o impai ed use s’ needs. As a i s s ep, in his pape we su ey how a IMS accessibili y speci ica ions co e WCAG, and discuss he con enience o ex ending i o he whole WAI guidelines. Secondly, we a gue how accessibili y could be conside ed as a key issue o p omo ing eusabili y. We con inue explaining why using a seman ic amewo k (such as he MPEG-7 seman ic ool, RDF o OWL) o desc ibing ex ual and con ex ual in o ma ion in a s anda dized manne could p omo e bo h, accessibili y and eusabili y. Finally, we explain how some accessibili y issues ha e been al eady add essed by Xime iX’s ximDEX, a seman ic-web Con en Managemen Sys em (CMS). We conclude p oposing a plan o be e in eg a e he accessibili y speci ica ions and con ex ual desc ip ion ools in o ha CMS. Keywo ds: Me ada a, Accessibili y, Reusabili y, CMS, Dublin Co e, IEEE-LOM, IMS-AccessFo All, ACCMD, IMS-Lea ne -In o ma ion-P o ile, ACCLIP, Seman ic Web, MPEG-7, RDF, OWL. 1 In oduc ion In he ACCMD and ACCLIP speci ica ions, he e m disabili y has been e-de ined as a misma ch be ween he needs o he lea ne and he educa ion o e ed, i.e. he abili y o he lea ning en i onmen o adjus o he needs o all lea ne s [5]. Ne e heless, he needs and p e e ences o a use may a ise om he con ex o en i onmen he use is in, he ools P omo ing accessibili y by using me ada a in he amewo k o a seman ic-web d i en CMS Rocío Ga cía-Robles Robo ics and Compu e Technology o Rehabili a ion Lab. Uni e si y o Se ille (SPAIN) Tel: +34 95 4556144 Fax:+ 34 95 4556449 [email p o ec ed] Fe nando Díaz del Río Robo ics and Compu e Technology o Rehabili a ion Lab. Uni e si y o Se ille (SPAIN) Tel: +34 95 4556144 Fax:+ 34 95 4556449 [email p o ec ed] An ón Ci i Robo ics and Compu e Technology o Rehabili a ion Lab. Uni e si y o Se ille (SPAIN) Tel: +34 95 4556470 Fax:+ 34 95 4556449 [email p o ec ed] Juan An onio P ie o Xime iX ne wo k hough s SL Tel: +34 91 3645475 [email p o ec ed] DC-2005: P oc. In . Con . on Dublin Co e and Me ada a Applica ions 2005 ~71 ·This wo k has been pa ially suppo ed by he SIC (Se icio de In o má ica y Comunicaciones) o he Uni e si y o Se ille. a ailable (e.g., mobile de ices, assis i e echnologies such as B aille de ices, oice ecogni ion sys ems, o al e na i e keyboa ds, e c.), hei backg ound, o a disabili y in he adi ional sense [5]. Accessible sys ems adjus he use in e ace o he lea ning en i onmen , loca e needed esou ces and adjus he p ope ies o he esou ces o ma ch he needs and p e e ences o he use . The e o e, accessibili y no ion has been enla ged in he IMS scope, o add essing no only impai ed people needs, bu also o he use s’ (lea ne s’) p e e ences. On he o he hand, he e a e wo sides o he ma ch needed o add ess he use s’ needs and p e e ences. One speci ies wha he use needs o p e e s, and i is cu en ly desc ibed by he ACCLIP. [5] The o he labels esou ces using he same e ms, and i is cu en ly desc ibed by he ACCMD. Resou ce accessibili y desc ip ion is also being add essed by he DC-Accessibili y Elemen and IEEE-LOM, as i is u he explained in nex sub- sec ions. 1.1. The IMS AccessFo All In o ma ion Model The inal goal o his IMS speci ica ion is o p o ide unc ional in e ope abili y o suppo he subs i u ion o augmen a ion o one esou ce wi h ano he when his is equi ed o accessibili y pu poses, as p esc ibed in he use ’s p o ile (e.g., he addi ion o cap ion ex o a hea ing-impai ed con ex ), hus allowing in e ope a ing sys ems o wo k oge he o se e he needs o lea ne s wi h disabili ies and o he s who ha e ACCMD p o iles. The IMS o e all accessibili y da a model [6] consis s o he desc ip ion o one p ima y esou ce, and he desc ip ion o he ea u es o none, one o mo e esou ce(s) ha a e equi alen s o a pa icula p ima y esou ce. A p ima y esou ce is allowed o poin o ze o o mo e equi alen esou ces. An equi alen esou ce is allowed o poin o a single p ima y esou ce only. In his way, ci cula e e ences a e a oided and he ela ionship model is g ea ly simpli ied wi h no loss o unc ionali y. The p ima y esou ce me ada a desc ibes: -Access Modali y: I includes ou a ibu es such as hasVisual, hasAudi o y, hasTex , and hasTac ile, which a e boolean alues o indica e whe he o no he esou ce con ains isual, audi o y, ex ual o ac ile equi alen con en in o ma ion. -Adap abili y: How amenable he esou ce is o ans o m he display and whe he he me hod o con ol is lexible (display ans o mabili y and con ol lexibili y). -Equi alen : Whe he he e is a known equi alen al e na i e. I is a poin e o an equi alen esou ce (me a-da a) o he desc ibed esou ce o pa s he eo . The equi alen esou ce da a model con ains h ee elemen s ha a e con aine s o con en p esen ed in a di e en modali y: al e na i esToVisual (colou a oidance such as ed, o ange, ed/g een,…… o he use o maximum con as monoch ome); al e na i esToTex (e.g. g aphic al e na i e o sign language al e na i es o ex in he p ima y esou ce); al e na i esToAudi o y (cap ions, educed eading le el, educed speed, o he a ailabili y o sign languages al e na i es). The o he elemen a ibu es a e he lea ne Sca old, and he con en , bo h o hem di ec ly ela ed o he lea ning app oach o he IMS speci ica ions. Ne e heless, he o he h ee elemen s desc ibe he accessibili y equi emen s ela ed o impai men s, and he e o e a e ela ed o he WCAG de eloped by he W3C. To apply an accessibili y app oach acco ding o ACCMD, he no mal wo k low would be: A-Ask use , (a leas i s ime using a new applica ion), o his/he p e e ences. The mos likely way is h ough an in e ac i e o m (‘wiza d’) ha p esen s a numbe o ques ions o he use and, gi en esponses o he ques ions, gene a es he p o ile. The p o ile should be ac ed on each ime he use uses ha applica ion, and he implemen e s should ensu e ha hei in e ace makes i easy o ac hem o , o o modi y he p o iles by he use . B- When a use sea ches o con en , he use ’s p o ile should be aken in o accoun when displaying he sea ch esul s. The e o e, once esou ces ma ching he sea ch c i e ia a e ound, he me ada a o hese esou ces should be examined o de e mine i he esou ce ma ches he p e e ences in he use ’s p o ile. The esou ces should be anked acco ding o how well hey ma ch each p e e ence and any pa ial ma ches should be lagged as such. The usage elemen s in he use ’s p o ile should be used o ank he esou ces. Use s should be gi en he op ion o eques ing ha pa ial o non-ma ches be omi ed om he sea ch esul s. C-I he eques ed esou ce has no ACCMD, he sys em should wa n he use . I he eques ed esou ce has ACCMD, he sys em should ma ch he use p e e ences. This p ocess would be no mally au oma ed, bu bes p ac ice ecommends ha use con ol o e he au oma ion beha iou be an implemen a ion ea u e o he sys em 1.2. The DC Accessibili y Elemen The DC-Accessibili y Wo king g oup (DCA-WG) is p oducing a se o documen s ha could lead o he c ea ion o a new DC elemen o be called DC:Accessibili y. The desc ip ion o he e m should be simpli ied and some possible ex alues o he e m should be speci ied [9]. The unde lying in o ma ion model o he new e m could be closely ela ed o he ACCMD ha desc ibes people’s accessibili y needs and p e e ences. Bo h speci ica ions, o people and o esou ces, we e de eloped in collabo a ion wi h he IMS Global 72 DC-2005, Sep embe 12-15 - Mad id, Spain P ojec and hey a e main ained by ha body. To comple e he wo k, DC needs an applica ion p o ile o elemen se ha desc ibes people in which hei accessibili y needs can be included. The e o e, his app oach o accessibili y, as he one adop ed by he IMS, depends upon no jus accessible con en 1 (WCAG con o man ), bu also ha esponsibili y o accessible con en deli e y be aken by he se e . This is a shi om ea lie app oaches which depended solely on WCAG/ATAG/UAAG con o mance. I is consis en wi h o he wo ks ha aims o p o ide mo e de ice lexibili y o use s. Fu he in o ma ion on he DC:Accessibili y elemen could be published in he DCMI websi e2. 1.3. The IEEE LOM and CEN-ISSS The Eu opean S anda diza ion body, CEN-ISSS has s a ed a Lea ning Technology Wo kshop on Accessibili y P ope ies o Lea ning Resou ces (CEN-ISSS LTW APLR). The main objec i es o ha wo kshop a e [10]: -To demons a e o ma i e ways ha he IEEE LOM can be used o documen in o ma ion abou he accessibili y p ope ies o lea ning con en (lea ning objec s) in s anda d ways. - To de elop a basic ocabula y and amewo k a ound which so wa e endo s, ool p oduce s and con en au ho s can wo k in o de o p o ide a g ea e le el o in e ope abili y and applicabili y o ools. The esul s o ha on-going p ojec will be [10] -Accessibili y applica ion p o ile o he IEEE LOM o desc ibe accessibili y equi emen s (CWA); -Recommenda ions o u he wo k in he ligh o global accessibili y a chi ec u e and me a-da a de elopmen s and po en ials o use - ials. Pa o hose esul s will be [10]: -Me ada a Vocabula ies, con aining accessibili y ocabula ies o desc ip ion o accessibili y cha ac e is ics o lea ning esou ces. -IEEE LOM Applica ion P o ile and Binding, con aining he in o ma ion model o he Accessibili y applica ion p o ile o he IEEE LOM and he co esponding RDF Binding. -Accessibili y Con o mance Tes ing Plan, a con o mance es ing plan wi h he Accessibili y applica ion p o ile o he IEEE LOM. The ac i i y o he CEN-ISSS LTW APLR is being coo dina ed and ha monized wi h o he in e na ional s anda ds o ganiza ions such as IMS, ISO, DC and W3C/WAI [8]. The e is no single uni e sally accep ed axonomy o unc ional me ada a ha sui s he pu pose o con en adap a ion o he indi idual o accessibili y. I is he ecommenda ion o his g oup ha such a axonomy be de eloped and kep in a public me a-da a egis y o e ing mul ilingual and cul u al-con ex anspa ency and be e e enced o con en - ela ed alues [10]. A s ep owa ds his wo k is p o ided by he ex ensions o LOM, which include [10]: -Requi ed new ocabula y alues o Rela ion:Kind displayT ans o mabili y con olFlexibili y equi alen Resou ce al e na i eFo supplemen a yFo -New elemen wi hin Rela ion:Iden i ie Pa Ca alog En y The e o e, a e his b ie in oduc ion o he wo k unde de elopmen by he CEN-ISSS LTW APLR, we can conclude ha i is also a lea ning o ien ed accessibili y speci ica ion, whose main goal has been basically o adap he IMS ACCMD speci ica ion o he IEEE-LOM s anda d. The unde lying accessibili y in o ma ion model is exac ly he same, bu using di e en label names. Some issues s ill need e inemen because he wo k is s ill in p og ess. 2. The IMS accessibili y speci ica ions and he WCAG Web Con en Accessibili y Guidelines (WCAG) a e cu en ly a de ac o s anda d o check Web con en accessibili y o impai ed people. WCAG con ains an exhaus i e lis o checkpoin s o guidelines ha a page should ul ill i i is o be conside ed as accessible by e e ybody. The i s e sion [1] o ha lis (WCAG 1.0, 1999) was somewha echnology o applica ion dependen : many checkpoin s we e add essed o an h ml implemen a ion o pages. This ac was censu ed many imes by web communi y. Ne e heless he eedback and dissa is ac ion a ound e sion 1.0 has d i en WAI Wo king G oup o p oduce a mo e “ obus ” ( echnology independen ) WCAG 2.0 guidelines. Those a e cu en ly in p og ess, bu d a e sion [2] is clea enough o unde s and his end. Ano he p oblem s ill emains: au oma ic checking o accessibili y o a page is a challenge. Some ools ha e been de eloped o add ess ha issue, bu a web p og amme can mislead hose ools. Fo example, i a page includes an emp y ag as “al e na i e” desc ip ion o a non- ex ual elemen , mos o checking ools will assume ha al e na i e desc ip ion is co ec ly co e ed. In ac , ac ually, a CMS mus gua an ee ha all he p ope ies o e i y accessibili y o a desi ed le el a e p o ided ei he di ec ly om he con en c ea o (policy-1) o indi ec ly using ules o ex ac hem om he con ex o om p e ious elemen s o DC-2005: P oc. In . Con . on Dublin Co e and Me ada a Applica ions 2005 73 1Being c ea ed wi h good au ho ing ools o use wi h good use agen s (ATAG and UAAG complian ). 2Ne e heless, i is impo an o ema k ha due o he ac ha he e is a p oposal pending in he DCMI in ela ion o a possible accessibili y elemen , i can no assume ha he o icial publica ion is a p o o ma s ep. in o ma ion in he hie a chy (policy-2). The CMS p esen ed in his pape , ximDEX, has implemen ed bo h policies. On he o he hand, a u he s ep ollowing WAI G oup ini ia i e would be o p omo e disco e y o ma e ial ha ing app op ia e accessibili y suppo , as well as he adjus men o con ol and display o esou ces o mee use accessibili y needs and p e e ences [8], (as explained in sec ion 1.1 o he cu en documen ). This is pa ially add essed by he IMS ACCMD and ACCLIP speci ica ions. The unde lying In o ma ion Models o bo h o hem a e no exhaus i e, bu he add essed accessibili y issues a e sui ably s uc u ed in a hie a chically manne . So, al hough he concep o accessibili y is mainly aimed o he ield o elec onic lea ning in IMS speci ica ions, we conside i is jus a p omising s a ing poin . We sugges ha i is a key issue o ex end he IMS In o ma ion Models o including all WAI guidelines. Ne e heless, ha is no a i ial wo k, no an easy ask. Fi s o all, IMS de ines a model (ACCLIP) which desc ibes and eco ds use p e e ences, i.e. he use p o ile. This model is he base o la e adap page elemen s o he use . Then, his model should be augmen ed o ake in o conside a ion all he abili ies o e e y po en ial Web use (so ha i co e s all ea u es encoun e ed in WCAG guidelines). So e e y use and Web de ice (use agen in WAI e minology) will ha e o alue he pa ame e s o he use p o ile be o e displaying con en . Mo eo e , hose pa ame e s may be uned along he new accesses o eco d mo e exac ly he cha ac e is ics o he use . F om he con en display poin o iew, i will be necessa y o de ine he accessibili y p ope ies o each elemen o a page. Wi h espec o accessibili y, Web elemen s can be classi ied in o some ew g oups: ex ual, links, audio, ideo, pic u es, ables, cha s and ew mo e. Each one has di e en p ope ies ha will de ine i s accessibili y ea u es. Fo example, audio con en has wo impo an p ope ies: con aining ele an in o ma ion, o playing he ole o en e ainmen elemen s. On he second le el o he hie a chical p ope ies, he audio elemen s ha con ain ele an in o ma ion will ha e an impo an p ope y: being ex ual (e.g. ly ics o a song, cap ion o an audio con e ence,……). Then, an elemen wi h his las p ope y will inhe i he no mal ex ual p ope ies. Conside ing he p ope ies o all elemen s o a page, he use disabili ies and p e e ences and de ice ea u es, he b owse would display he page in o ma ion in he mos app op ia e manne . Ob iously, he e is oo much wo k o do in ela ion wi h he p e ious p oposal. The con e sion o WCAG 1.0 checkpoin s in o WCAG 2.0 guidelines has inc eased accessibili y abs ac ion, which can help as a i s s ep o model con en accessibili y p ope ies in a echnology independen way. Bu i is necessa y o go on. 2.1 O e iew on cu en ends in ela ion o he de elopmen o a comple e accessibili y speci ica ion IMS has al eady de eloped he accessibili y speci ica ions hey needed o lea ning and lea ne s pu poses. Bu IMS does no in end o do he ACCLIP and ACCMD comple ely o esemble he WCAG, as i can be in e ed by he ollowing s a emen : “Me a-da a o asse compliance o an accessibili y speci ica ion o s anda d is no wi hin he scope o his speci ica ion.” [5] Simul aneously, he DC Me ada a Ini ia i e (DCMI) is cu en ly wo king on he DC Accessibili y Elemen . DCMI usually ends o ge he minimum se o agging elemen s, while IMS usually de elops e y de ailed and huge speci ica ions, whose in o ma ion models a e usually e y hie a chical. Conce ning he wo k unde de elopmen by he CEN/ISSS in ela ion o he IEEE LOM speci ica ion, ha is also a ho izon al speci ica ion and axonomy o ien ed, as he DC Me ada a Se . IEEE LOM and IMS speci ica ions a e e y lea ning o ien ed, while DC is much mo e gene ic. Taking in o accoun all hese ac o s, i is mo e likely ha he DCMI and he CEN/ISSS a e in e es ed in enla ging i s speci ica ion o complying wi h he ACCMD han comple ing he ACCMD o co e ing he whole WCAG and o he WAI guidelines. Ne e heless, i would e y con enien o con inue enla ging and e ining he IMS accessibili y speci ica ions o co e all he WCAG, because IMS, DC and IEEE ha e ini ia ed he s anda diza ion p ocess which logically ollows he p e ious wo k unde aken by he W3C, bu no all he accessibili y guidelines a e add essed ye . 2.2 WCAG 1.0 s. WCAG 2.0 Al hough WCAG 2.0 a e nowadays only a wo king d a , i is impo an o ake in o accoun he main di e ences ela ed o e sion 1.0, be o e compa ing WCAG wi h he ACCMD. Some o he main di e ences be ween bo h a e he ollowing ones [8]: 1-WCAG 2.0 ep esen s b oad concep s ha apply o all Web-based con en . They a e no speci ic o HTML, XML, o any o he echnology s. e sion 1.0 which was highly echnology dependen . 2-Whe e WCAG 1.0 uses guidelines o g oup checkpoin s, WCAG 2.0 uses guidelines o g oup success c i e ia. Whe e WCAG 1.0 assigns a p io i y o a checkpoin , WCAG 2.0 ca ego izes a success c i e ion in o one o h ee le els. The e o e, newes e sion is mo e e icien ly o ganized. 3-WCAG 2.0 may adjus he p io i y o some checkpoin s. We conclude ha because WCAG 2.0 is mo e abs ac , i is easie o 74 DC-2005, Sep embe 12-15 - Mad id, Spain compa e i wi h he ACCMD, as we will see in nex sec ion. 2.3 IMS AccessFo All s. WCAG 2.0 Compa ing WCAG 2.0 Design Guidelines ( op laye ) wi h he ACCMD in o ma ion model, we can obse e ha WCAG p inciples 1, 2 and 4 a e pa ially co e ed: -P inciple 1: Con en mus be pe cei able. This means (1.1) he e mus be ex al e na i es o all non- ex con en ; (1.2) p o iding synch onized al e na i es o mul imedia (cap ions and audio desc ip ions); (1.3) ensu ing ha unc ionali y and s uc u e a e sepa able om p esen a ion. -P inciple 2: In e ace elemen s in he con en mus be ope able. This means (2.1) Making all unc ionali y ope able ia a keyboa d in e ace; (2.2) allowing use s o con ol ime limi s on hei eading o in e ac ion; (2.3) allowing use s o a oid con en ha could cause pho osensi i e epilep ic seizu es; (2.4) p o iding mechanisms o help use s ind con en , o ien hemsel es wi hin i , and na iga e h ough i . -P inciple 4: Con en mus be obus enough o wo k wi h cu en and u u e echnologies. This means (4.1) using echnologies acco ding o speci ica ion; (4.2) ensu ing ha use in e aces a e accessible o p o ide an accessible al e na i e(s). Mos o he abo e men ioned design p inciples a e only pa ially suppo ed by he ACCMD. Fo example, some o he unco e ed design p inciples a e lis ed below: -P inciple 1.4: Making i easy o dis inguish o eg ound in o ma ion om backg ound images o sounds. -P inciple 2.5: Helping use s a oid mis akes and make i easy o co ec hem. -P inciple 3: Con en and con ols mus be unde s andable. Tha means (3.1) ensu ing ha he meaning o con en can be de e mined; (3.2) o ganizing con en consis en ly om “page o page” and making in e ac i e componen s 5 beha e in p edic able ways. The a o emen ioned design p inciple 3 may be managed by using o he IMS speci ica ions such as IMS Simple Sequencing o IMS Lea ning Design, bu bo h o hem a e lea ning o ien ed. In ou opinion, one o he nex s eps would be inding he in o ma ion model ha ela es as much as possible he WCAG guidelines, by enla ging he cu en speci ica ion, and making i less dependen on he lea ning app oach. The e is also a need o de eloping ools o display con en in an accessible way. Fo example, he abo e men ioned p inciple 1.4 could be managed by using he sui able ools. Bu a he same ime, i would be in e es ing o ha e a me ada a elemen o desc ibing o a conc e e con en esou ce i he o eg ound in o ma ion is easily dis inguishable om backg ound image o sound, ( ha label could be illed up by a pe son, o au oma ically by a diagnos ic ool). 2.4 Tex ual In o ma ion is he linking o ma be ween accessible and no accessible con en Acco ding o he i s design p inciple o he WCAG 2.0 “con en mus be pe cei able”. This means (1.1) he e mus be ex al e na i es o all non- ex con en ; (1.2) p o iding synch onized al e na i es o mul imedia (cap ions and audio desc ip ions); (1.3) ensu ing ha unc ionali y and s uc u e a e sepa able om p esen a ion. I we analyze he implica ions o ha design p inciple, we can in e ha ex ual o ma ac s as a middlewa e o accessibili y pu poses. On one hand, isual in o ma ion needs ex ual desc ip ion in o de o be ansla ed o o he o ma s (e.g. audi i e, sign language). On he o he hand, in o ma ion in audio o ma also needs o be cap ioned as a p e ious s ep o i s ansla ion o o he accessible o ma s, o example o a hea ing-impai ed con ex . Some imes non- ex o ma can be cap ioned, bu some imes i mus be jus desc ibed, i.e. i mus be con ex ualized. The e o e, as we will explain in nex sec ion, he e should be p ope suppo o desc ibing ex ual and con ex ual in o ma ion. 3. A u he s ep: S anda diza ion on he desc ip ion o ex ual and con ex ual in o ma ion As explained in he p e ious sec ion, ex ual in o ma ion is he linking o ma be ween non- accessible and accessible con en . In ou opinion, accessibili y can be conside ed one key issue o p omo ing eusabili y (unde s ood as he capaci y o con en o be eused in in a and in e con ex ual scena ios). On one hand, he wide he po en ial use communi y is, including disabled people, he wide he chances o eusing con en . On he o he hand, as explained in p e ious sec ion, in o de o suppo accessibili y i is use ul o o ganize he in o ma ion in a ex ual o ma and, as a consequence, once he in o ma ion is in ha o ma i is easie o euse i u he on. The e o e, accessibili y me a-in o ma ion con ibu es o enla ging he eusabili y capaci y o con en . So, o make con en mo e accessible is also o make i mo e eusable. I is a powe ul ad an age i we ake in o accoun ha he human esou ces cu en ly needed o de eloping con en binding IMS, DC, IEEE and o he speci ica ions is eno mous. Due o ha eason, eusabili y could e en be conside ed a eal goal, be e han jus a desi able. I we hink in e ms o eusabili y, acco ding o [13], he e a e h ee key ac o s p omo ing i : (a) g anula i y ( he lowes he be e o eusabili y pu poses); (b) localiza ion (me ada a is mainly suppo ing ha aim); and (c) sel - con ained-ness, (unde s ood as he capaci y o con en o be con ex independen ). Conce ning he las ac o , DC-2005: P oc. In . Con . on Dublin Co e and Me ada a Applica ions 2005 75 de eloping neu al con en is agains he usual con en au ho ing wo k low, because human beings no mally con ex ualize when au ho ing con en . So, de- con ex ualiza ion and e-con ex ualiza ion a e eques ed s ages no mally when ying o euse con en . The e o e, we can conclude ha desc ibing con ex (no mally exp essed as ex ual in o ma ion), could p omo e con en eusabili y, as well as accessibili y. I could ac as a acili a o o inding con ex ual issues in a speci ic con en , in a p e ious s ep o he de-con ex ualiza ion and e- con ex ualiza ion o con en . Consequen ly, i could be in e es ing o desc ibe ex ual and con ex ual in o ma ion using a speci ica ion 3 , e.g. a seman ic amewo k. In o de o suppo con ex desc ip ion, se e al app oaches a e possible. I we wan o desc ibe small pieces o in o ma ion, e.g. ques ion i ems, a domain on ology suppo ed by OWL o RDF could be a solu ion. On he o he hand, i we wan o desc ibe highe g anula i y pieces o in o ma ion (bo h da a and p ocesses), o he ypes o na a i e o ien ed solu ions could be be e used. Indeed, he e a e some s anda d speci ica ions o he desc ip ion o con ex . In IMS lea ning o ien ed speci ica ions, as well as he DC Elemen Se and he IEEE LOM, con ex is cu en ly mainly desc ibed in e ms o domain ocabula ies used in he me ada a ags. The Desc ip ion and Tex elemen s o he DC Me ada a Se , IMS-Me ada a and he IEEE-LOM can also be used o ex ual desc ip ion. RDF and OWL a e also e y powe ul ools o desc ibing con ex in an on ological o ien ed manne . Ano he speci ica ion which may suppo he desc ip ion o con ex is he IMS-Lea ning Design (IMS-LD) [11]. I does i using an unde lying na a i e syn ax (exp essed in e ms o oles playing ac i i ies using esou ces). The main disad an age o using his speci ica ion o con ex desc ip ion is ha i is o ien ed o he pedagogical desc ip ion o lea ning expe iences. So, i can be e y good, o example o desc ibing a uni o lea ning o lea ning scena io, bu i could be no sui able o gene al pu poses. Ano he speci ica ion o con ex desc ip ion is he MPEG-7, [14] being much mo e gene ic han he IMS-LD. I suppo s he desc ip ion o bo h: he s uc u e ( ideo segmen s, mo ing egions, e c) and he seman ic. The MPEG-7 seman ic en i y ools desc ibe seman ic en i ies (such as na a i e wo lds, objec s, e en s, concep s, s a es, places and imes), as well as seman ic ela ionships be ween hem. In MPEG-7 e en s a e unde s ood as occasions when some hing happens. Objec s, people and places can popula e such occasions and he imes a which hey occu . Fu he mo e, hese en i ies can ha e p ope ies and s a es h ough which hey pass as wha is being desc ibed anspi es. Finally, he e is he wo ld in which all o his is going on, he backg ound, he o he e en s and o he en i ies, which p o ide con ex o he desc ip ion. [14] The main ad an age o using MPEG-7 would be o gi e seman ic s uc u e o he desc ip ion. Tha seman ic s uc u e could be e y use ul o suppo ing design p inciples 3 and 2.5 o he WCAG 2.0. Ano he addi ional ad an age o using MPEG-7 speci ica ion is ha i is a gene ic speci ica ion de eloped o desc ibing mul imedia con en and, as explained in p e ious sec ions, we a e discussing he con enience o desc ibing non- ex ual in o ma ion o accessibili y as well as o eusabili y pu poses. The e o e, we can conclude ha he main ad an age o he a o emen ioned explained solu ions (OWL/RDF, DC Elemen Se , IEEE-LOM, IMS- Me ada a4), is ha hey a e na u al language o ien ed, and p obably hey a e less cos ly in e ms o human and machine esou ces. IMS-LD and MPEG-7 a e mo e complex and na a i e o ien ed solu ions, bu maybe oo cos ly in p ac ice i hey a e used o desc ibing con ex . 4. XimDex: A Seman ic CMS The seman ic Con en Managemen Sys em ximDEX [3] is a isual amewo k de eloped by Xime iX o he c ea ion o web con en s unde he pa adigm o he Seman ic Web. The main ocus o he pla o m is he abs ac ion o con en s and se ices, o e ing a dis ibu ed and isual en i onmen o he anno a ion and pa ame e isa ion o elemen s o in o ma ion ha a e agg ega ed in o a hie a chy o documen s in a classic web po al app oach and in o nodes and ela ionships con o ming seman ic eposi o ies o in o ma ion o he managemen o Seman ic po als. Elemen s o in o ma ion ep esen ing con en s and se ices a e g ouped in o documen s ep esen ed ia a neu al seman ic o ma [4]. Du ing he anscoding (con e ing om one o ma o ano he ) s age [15, 16], a p o iling o hese elemen s o in o ma ion is made o c ea e inal exploi able o ma s. 4.1 Accessibili y buil in ximDEX E e y elemen o in o ma ion composing a documen o se ice has me ada a p o ided by he c ea o s and/o calcula ed om in e ences using he ins an aneous con ex o he elemen o in o ma ion (ances o ’s p ope ies o ins ance) in o de o p o ide addi ional unc ionali ies and o gua an ee he accomplishmen o a ge s (whe e accessibili y is 76 DC-2005, Sep embe 12-15 - Mad id, Spain 3A p o-s anda d speci ica ion. 4Excep o he IMS-LD, which has a na a i e app oach in he con ex o he desc ip ion o pedagogical scena ios. conside ed a main one). Tha explained ans o ma ion is encoded in o ules and empla es using he seman ic abs ac ion o he elemen s o in o ma ion, concep ually a a highe le el han he syn ac ic ans o ma ion p o ided by XSLT, allowing ximDEX o make assump ions and in e ences o gua an ee he co ec adap a ion o con en s conside ing accessibili y speci ica ions. 5. Conclusions We can conclude ha is a key issue o ex end he IMS speci ica ions o binding all WAI guidelines. The con e sion o WCAG 1.0 checkpoin s in o WCAG 2.0 guidelines has inc eased accessibili y abs ac ion, which can help as a i s s ep o model hose con en accessibili y p ope ies and lea ne p o ile in a echnology independen way. I is also in e es ing o keep in mind ha ex ual in o ma ion is he linking o ma be ween accessible and no accessible con en , ac ing as a middlewa e o accessibili y pu poses. Some imes in o ma ion in a non- ex o ma can be cap ioned, bu some imes i mus be jus desc ibed, i.e. i mus be con ex ualized. So, he e should be p ope suppo o desc ibing ex ual and con ex ual in o ma ion. One main bene i o ha app oach would be ha desc ibing con ex using s anda d seman ic speci ica ions, could p omo e con en eusabili y, as well as accessibili y. I could ac as a acili a o o inding con ex ual issues in a speci ic con en , in a p e ious s ep o he de-con ex ualiza ion and e-con ex ualiza ion o con en . The e o e, nex s eps in ximDEX, in o de o suppo seman ic desc ip ion o con ex , will be o use he seman ic con en managemen sys em ximDEX o es ing he bes solu ion be ween hose discussed in p e ious sec ion, p omo ing also he in e ope abili y wi h o he con en desc ip ion speci ica ions: -Using DC Me ada a Se and IMS Me ada a. -Using he MPEG-7 Seman ic Tool. - Applying an on ology o ien ed app oach desc ibed in RDF [17]. The Seman ic CMS ximDEX is al eady p epa ed o es ing ha solu ion ia he desc ip ion o he con ex o e e y elemen o in o ma ion h ough an on ology. Also, he p esen a ion laye can be managed ia a isualiza ion on ology. We will also es he easibili y o using ACCMD (o an ex ended speci ica ion de eloped by us o ying o co e WCAG). Re e ences 1. h p://www.w3.o g/TR/1999/WAI-WEBC ONTENT-19990505/ ull-checklis N. 2. h p://www.w3.o g/TR/2004/WD-WCAG 20- 20041119 3. h p://www.xime ix.com/p oduc os/ximD EX 4. J. A. P ie o, J. Villa , D. Gómez, M. Es ellés, “Seman ic Managemen o Web Con en s using ximDEX” (in Spanish), P oc. I Open Sou ce Wo ld Con e ence, Málaga, Spain, Feb. 2004. 5. IMS AccessFo All Me ada a O e iew, www.imsp ojec .o g 6. IMS AccessFo All In o ma ion Model, www.imsp ojec .o g 7. IMS AccessFo All Bes P ac ice and Implemen a ion Guide, www.imsp ojec .o g 8. Web Con en Accessibili y Guidelines 2.0 www.w3c.o g 9. Dublin Co e Me ada a Ini ia i e, dublinco e.o g 10. CEN-ISSS LTW APLR, www.cen-apl .o g 11. IMS Lea ning Design www.imsp ojec .o g 12. IMS Simple Sequencing, www.imsp ojec .o g 13. Duncan, C: G anula isa ion, Reusing online esou ces: A sus ainable app oach o e-lea ning, 2003, Chap e 2, ISBN: 0749439491 14. Manjuna h, B.S.(ed): In oduc ion o MPEG 7: Mul imedia Con en Desc ip ion Language, John Wiley & Sons, ISBN: 0471486787 15. R. Mohan, J. Smi h, C.-S. Li: Adap ing Mul imedia In e ne Con en Fo Uni e sal Access, IEEE T ansac ions on Mul imedia, Ma ch 1999, pp. 104-114. 16. Whi e Pape : IBM T anscoding Solu ion and Se ices 17. h p://www.w3.o g/RDF/ DC-2005: P oc. In . Con . on Dublin Co e and Me ada a Applica ions 2005 77