1. Web ng ngha l g?Tim Berners-Lee: Web c ng ngha l s m rng ca WEB hin ti m trong thng tin c nh ngha r rng sao cho con ngi v my tnh c th cng lm vic vi nhau mt cch hiu qu hn. (c nh ngha my tnh x l c, tch hp DL ng; DL/tri thc c s dng li thng qua cc ng dng khc nhau) Theo nh ngha ca T chc World Wide Web (W3C): WebNN l mt cch nhn v cch thc t chc d liu: l tng v vic d liu trn Web c nh ngha v lin kt theo mt cch m n c th c s dng bi my tnh vi mc ch khng ch cho vic hin th m cn t ng ho, tch hp v s dng li d liu qua cc ng dng khc nhau.Phn bit WebNN vi Tr tu nhn to: TTNT l lm cho my tnh thng minh hn cn WebNN l lm cho ng dng thng minh hn (Biu din thng tin, DL theo cch no ng dng c th hiu c)Ti sao cn n WebNN: Vn chnh vi Web hin nay l ni dung web thiu ng ngha, dn n vic tm kim DL trn web ch yu da vo keyword v theo l:-Tm ra nhiu kt qutnh chnh xc thp-Khng c kt qu nu tm qu cht ch-Kq rt ph thuc vo s nhy cm ca t ng-Ngi s dng phi tn nhiu thi gian, cng sc x l kt qu tr v.Ni chung thao tc ch yu l thao tc trn ni dung thy c. Quan trng l my tnh khng hiu c ng ngha ca DL.2. Kin trc ca WebNN

Trong :-Unicode v URI: c s xy dng cc ti liu-XML+NS+XMLschema: Cng ngh xy dng ti liu bn cu trc-RDF v RDFs: m t siu DL trn WebNN-Ontology vocabulary: M t cc quan h cng nh cc khi nim trong min ng dng.-Logic: C s chun ha cc khi nim cho WebNN-Proof v Trust: L cc ng dng cao cp m WebNN mun t n cho Web hin ti.

Trong :-Unicode v URI: c s xy dng cc ti liu-XML: cng ngh xy dng ti liu bn cu trc.-RDF: Chun trao i siu DL WebNN-Ontology (RDFs, OWL) v ngn ng cc lut: M t cc quan h cng nh cc khi nim trong min ng dng v suy din ca chng.+SPARQL: ngn ng truy vn cho DL RDF v ontology-ng nht v logic: c s chun ha cc khi nim cho WebNN-Proof v Trust: L cc ng dng cao cp m WebNN mun t n ho web hin ti.-Tng trn cng: Giao din ngi dng v cc ng dng.Gii thch chi tit:T s kin trc ca Web ng ngha, ta thy c by tng kin trc. Trong , vi h thng Web hin ti (World Wide Web) l ang tng th hai.Unicode: l mt bng m chun chung c cc k t thng nht s giao tip trn tt c cc quc gia, p ng tnh nht qun ton cu ca web.URI (Uniform Resource Identifier): l k hiu nhn dng Web n gin. C th, n l mt xu ngn cho php nhn dng ti nguyn Web nh: vi cc xu bt u vi "http:" hoc "ftp:" m chng ta thng thy trn World Wide Web. Bt k mt ngi no cng c th to mt URI, v s hu chng v chng l mt cng ngh c s xy dng mt h thng Web ton cu. H thng World Wide Web c xy dng trn chng v bt k ci g m c mt URI th c coi l "trn Web".URL (Uniform Resource Locator): l mt dng c bit ca URI, c th n l mt a ch trn mng.(URI (Uniform Resource Identifier) c th hiu l mt chui nh danh ti nguyn trn mng. Mi mt ngun ti nguyn trn mng s c mt a ch duy nht xc nh n, chnh l URI. Mt dng thc quen thuc ca URI l URL (Uniform Resource Locator) c s dng nh danh mt a ch Web no trn Internet. Ni theo cch khc, URI l s m rng ca URL.)RDF (Resource Description Framework): Khung m t ti nguyn - RDF c W3C gii thiu cung cp mt c php chun to, thay i v s dng cc ch thch trong Web ng ngha. Mt mnh RDF l mt b ba c dng: [ch thuctnh itng]. Trong , ch l ti nguyn m c m t bng thuc tnh v i tng. Thuc tnh th hin mi quan h gia ch v i tng. Cn i tng y c th l mt ti nguyn hoc mt gi tr. Ba thnh phn trn trong RDF u l cc URI. RDFS (RDF schema): RDFS l mt ngn ng ontology n gin ca web ng ngha, c coi l mt ngn ng c s ca web ng ngha. RDFS l ngn ng m t b t vng trn cc b ba RDF. N cung cp cc cng vic sau:- nh ngha cc lp ti nguyn- nh ngha cc quan h gia cc lp- nh ngha cc loi thuc tnh m cc lp trn c- nh ngha cc mi quan h gia cc thuc tnh.Ontology Vocabulary: B t vng ontology c xy dng trn c s tng RDF v RDFS, cung cp biu din ng ngha mm do cho ti nguyn web v c kh nng h tr lp lun. xy dng c cc b t vng ny, ngi ta s dng cc ngn ng ontology biu din chng nh: RDFS, OIL, DAML, DAML+OIL, OWL, ... Cc ngn ng ny cung cp kh nng biu din v h tr lp lun khc nhau v chng da trn nn tng l cc ngn ng logic m t tng ng khc nhau.Tng Logic: Vic biu din cc ti nguyn di dng cc b t vng ontology c mc ch l my c th lp lun c. M c s lp lun ch yu da vo logic. Chnh v vy m cc ontology c nh x sang logic, c th l logic m t c th h tr lp lun. V logic m t c biu din ng ngha hnh thc (c trng ca l thuyt m hnh), v cung cp cc dch v lp lun, l c s h tr my c th lp lun v hiu ti nguyn.Tng Proof: Tng ny a ra cc lut suy lun. C th t cc thng tin c ta c th suy ra cc thng tin mi. V d: A l cha ca B, A l em trai C th khi ta c thng tin mi l C l bc ca B. c c cc suy lun ny th c s l FOL (First-Order-Logic). V tng ny hin nay cc nh nghin cu ang xy dng cc ngn ng lut cho n nh: SWRL, RuleML.Tng Trust: m bo tnh tin cy ca cc ng dng trn Web ng ngha. V d: c mt ngi bo x l xanh, mt ngi khc li ni x khng xanh, nh th Web ng ngha l khng ng tin cy? Cu tr li y c xem xt trong cc ng cnh. Mi ng dng trn web ng ngha s c mt ng cnh c th, chnh v th cc mnh trn c th nm trong cc ng cnh khc nhau khi ng ngha tng ng khc nhau nn cc mnh vn ng, ng tin cy trong ng cnh ca n. c c s chng minh v tin cy th cc lp lun c p dng l khng n iu v c cc c ch kim tra chng minh kt hp vi cng ngh ch k in t xc nhn tin cy. Cc ngn ng chng minh l ngn ng cho ta chng minh mt mnh l ng hay sai.3. RDF (Resource Description Framework): Khung m t t ti nguyn Khung m t ti nguyn (RDF) l mt ngn ng siu d liu biu din d liu trn Web v cung cp mt m hnh m t v to cc mi quan h gia cc ti nguyn. RDF nh ngha mt ngun ti nguyn (resource) nh mt i tng bt k c kh nng xc nh duy nht bi mt URI. Cc ngun ti nguyn c cc thuc tnh i km. Cc thuc tnh (predicate/property) c xc nh bi cc kiu thuc tnh v cc kiu thuc tnh c cc gi tr tng ng. Kiu thuc tnh biu din cc mi quan h ca cc gi tr c kt hp vi cc ti nguyn.M hnh d liu ca RDF l cc b ba (triple) gm: Ch-th (Subject): c xc nh bi URI c th. Thuc-tnh (Predicate): thuc tnh ca siu d liu, cng c xc nh bi mt URI. i-tng (Object): gi tr ca thuc tnh, c th l mt gi tr (literal) hoc mt URI.V d: D liu v tn h ca mt c nhn c m s (ID) xc nh

RDF m t siu d liu v cc ti nguyn trn Web. RDF da trn c php XML tuy nhin XML ch m t d liu, RDF cn c kh nng biu din ng ngha gia chng thng qua cc ti nguyn c nh danh bng URI. k ny chng ta s c mt ci nhn c th v bao qut hn v RDF.Thng tin v tri thc trn web ng ngha s dng lin kt URIs v RDF.Ging nh web ca vn bn, web ca d liu c xy dng da trn cc ti liu trn web. Tuy nhin, khng ging web ca vn bn, cc lin kt l quan trn vn bn biu din di dng HTML, web ca d liu lin kt cc thc th c t tn thng qua RDF. URIs xc nh cc loi i tng v khi nim.RDF chnh l nn tng trung tm ca web ng ngha. Trong khi XML cung cp c php m ha d liu th RDF m t siu d liu v cc ti nguyn trn Web. RDF da trn c php XML tuy nhin XML ch m t d liu, RDF cn c kh nng biu din ng ngha gia chng thng qua cc ti nguyn nh danh bng URI.*Nguyn l: Tim Berners- Lee tm tt 4 nguyn l nn tng cho hot ng ca d liu lin kt (Linked Data) trong bi bo Design Issues: Linked Data (2006):- S dng cc URIs xc nh, t tn cc thc th- S dng giao thc HTTP URI con ngi c th tm kim, duyt chng- Cung cp thng tin hu ch ( siu d liu, m t c cu trc) v cc thc th c t tn khi URI ca chng c duyt- Cha cc lin kt n cc URIs khc lin quan trong d liu va c duyt gip c th duyt cc thng tin khc lin quan.Hin ti c cc nh dng c php tun t ha ci t d liu lin kt, ch thch ng ngha nh RDF, RDFa, RDF/XML, N3, TurtleRDF - Resource Description Framework, nh dng d liu cho php m t thc th, ti nguyn v quan h ni ti gia chng bng b ba i tng thuc tnh gi tr ( subject predicate object).RDFa (RDF in attributes) b sung tp cc thuc tnh m rng cho XHTML nhng siu d liu trong vn bn web.

N3 (Notation3): c php phi XML ca RDF, c thit k d c hn so vi cc ch thch RDF/XML. Turtle (Terse RDF Triple Language) nh dng tun t ha cho cc th RDF, tp con ca N3. V d: M hnh RDF c ch thch bng XML chun3.1. M hnh RDF3.1.1. Namespace v Qualified name: Namespace l mt tp cc tn( name) , c nh danh bi cc URI, c s dng trong cc ti liu XML nh cc element type v attribute name.Mt namespace c khai bo s dng mt tp cc thuc tnh c c nh ngha. Tn ca mt thuc tnh phi c xmlns hay xmlns: nh l mt tip u ng.Cch khai bo mt namespace:NSAttName ::= PrefixedAttName | DefaultAttName PrefixedAttName ::= 'xmlns:' NCName DefaultAttName ::= 'xmlns' NCName ::= (Letter | '_') (NCNameChar)* NCNameChar ::= Letter | Digit | '.' | '-' | '_' | CombiningChar | ExtenderQualified name (QName) bao gm mt tip u ng c gn trc bi mt URI theo sau l du : v tn cc b. -Cch nh ngha mt QNameQName::= (Prefix ':')? LocalPartPrefix::= NCName LocalPart::= NCName-Cch dng QName i vi kiu d liu l elementSTag::= 'ETag::= '' EmptyElemTag::= ''3.1.2. B ba RDF (RDF triple)M hnh c bn ca RDF gm ba b phn sau: -Ti nguyn (Resources) l tt c nhng g c m t bng biu thc RDF-Thuc tnh (Properties) l c tnh hay quan h m t tnh cht ti nguyn-Pht biu (Statements) mi pht biu gm ba thnh phn sau +Subject (ch th): a ch hay v tr ti nguyn mun m t. +Predicate (thuc tnh): xc nh tnh cht ca ti nguyn. +Object (i tng): ni dung gn cho thuc tnh.Mi mt mnh (subject, predicate, object) cn gi l mt b ba (triple).

V d: Xt mnh 1 Le Van Son works for Semantic Groups

Mnh 2: Le Van Son was born in 1948

Mnh 3: Semantic Group is headquartered in Da Nang

Cc b ba lin kt vi nhau to thnh th RDF

Tp cc triple hp li to thnh th RDF (RDF Graph). Cc node trong th c th l cc subject v object trong triple v cc cung (arc) trong th l cc predicate. Nn mt triple cn c th c m t di dng node-arc-node. Hng ca th rt quan trng, cung ca th lun bt u t subject n object.3.1.3. Literal Literal c s dng biu din cc gi tr nh con s, ngy thng, chui... Bt c ci g c th biu din bi mt gi tri Literal cng c th c biu din di dng mt URI. Mt Literal c th l object ca mt pht biu nhng khng th l subject hay l predicate. Literal c hai kiu sau: plain literal hay l typed literal.-plain literal l mt chui c kt hp vi mt tag ty . Trong ngn ng t nhin ta c th gi n l mt kiu text.-typed literal hnh thnh bng cch kt hp mt chui vi nh danh URI biu dim kiu d liu c bit no n. Kt qu tr v l mt node trong th tng t nh kiu literal. Kiu gi tr c biu din bng typed literal s c nh x n kiu gi tr c bit m ta khai bo thng qua URI.3.1.4 Kiu d liu c cu trc v Blank node Hu ht cc d liu trn Web u lin quan n cc cu trc phc tp.Trong v d trn ngy ca trang web c to ra c khai bo bi thuc tnh exterms:creationdate, vi mt kiu d liu l plain literal. Cc mnh RDF (bao gm cc cung v node) sau s c biu din ra trong th vi node mi va to l subject. Xt th sau:

C th vit di dng tripple nh sau: exstaff:85740 exterms:address exaddressid:85740 . exaddressid:85740 exterms:street "1501 Grant Avenue" . exaddressid:85740 exterms:city "Bedford" . exaddressid:85740 exterms:state "Massachusetts" . exaddressid:85740 exterms:postalCode "01730" . Cch biu din thng tin c cu trc nh vy i hi phi c mt a ch URI exaddressid:85740 m t khi nim kt hp( a ch ca Mr Joe). Nhng khi nim nh th ny c th khng c s dng bi cc thnh phn khc trong th v chnh v vy nh danh ny khng cn thit. Chnh v vy ta nn dng mt node trng (blank node) biu din node ny.

V c th m t di dng tripple nh sau: exstaff:85740 exterms:address ??? . ??? exterms:street "1501 Grant Avenue" . ??? exterms:city "Bedford" . ??? exterms:state "Massachusetts" . ??? exterms:postalCode "01730" . ??? ch s hin din ca blank node. Trong trng hp th s dng nhiu blank node, phn bit cc blank node ta dng mt nh danh (blank node identifiers), c dng _:name, ch s hin din ca mt blank node. V d nh, trong v d ny nh danh _:joeaddress c s dng ch blank node (l a ch ca Mr Joe). Vit li tripple sau: exstaff:85740 exterms:address _:joeaddress . _:johnaddress exterms:street "1501 Grant Avenue" . _:johnaddress exterms:city "Bedford" . _:johnaddress exterms:state "Massachusetts" . _:johnaddress exterms:postalCode "01730" . 3.2. Cu trc RDF/XMLM hnh RDF th hin mt m hnh mc tru tng nh ngha metadata. C php RDF c dng to ra v trao i metadata. RDF da trn c php XML. C php c bn ca RDF c dng nh sau: [1] RDF ::= [''] description* [''] [2] description ::= '' propertyElt* '' [3] idAboutAttr ::= idAttr | aboutAttr [4] aboutAttr ::= 'about="' URI-reference '"' [5] idAttr ::= 'ID="' IDsymbol '"' [6] propertyElt ::= '' value ''| '' [7] propName ::= Qname [8] value ::= description | string [9] resourceAttr ::= 'resource="'tham chiu URI'"' [10] Qname ::= [ NSprefix ':' ] name [11] URI-reference ::= string, interpreted per [URI] [12] IDsymbol ::= (bt k ID no hp l no ca XML) [13] name ::= (bt k tn hp l no ca XML) [14] NSprefix ::= (bt k tip u ng namespace hp l no) [15] string ::= (bt k chui no) V d : Xt pht biu ex:index.html exterms:creation-date "August 16, 1999" . C php RDF/XML biu din cho pht biu trn nh sau:1. 2. 4. 5. August 16, 1999 6. 7. Trong : Dng 1: l khai bo XML, cho bit ni dung theo sau da trn c php XML v phin bn XML c dng.Dng 2 v 3: bt u vi th rdf:RDF , cho bit rng ni dung XML tip theo m t RDF. T kha ny xc nh ti liu ny c biu din di dng RDF. Tip theo l phn khai bo XML namespace c s dng trong ti liu, ty vo nhu cu v mc ch s dng m ta c th dng cc namespace khc nhau cho tng ti liu. Dng 4, 5, 6: m t nhng mnh RDF. m t bt k pht biu no dng RDF/XML c th dng rdf:Description, v rdf:about , y chnh l subject ca pht biu. Th bt u rdf:Description trong dng 4 cho bit bt u m t v mt resource, v tip tc nh danh resource ny dng thuc tnh rdf:about ch ra URI ca subject resource. Dng 5 cung cp 1 phn t thuc tnh, vi Qname exterms:creation-date nh l th ca n. Ni dung ca phn t thuc tnh ny l object ca statement, c gi tr l kiu plain literal August 19, 1999 . Dng 7: cho bit kt thc ca th rdf:RDF bt u dng 2 v cng l th kt thc ca ti liu RDF3.3. RDF Container m t tp hp ca nhiu i tng nh 1 quyn sch c vit bi nhiu tc gi, danh sch cc hc vin trong 1 kho hc, v.v... RDF cung cp nhiu kiu v nhiu thuc tnh tch hp sn gip m t c nhng tp nh vy, trong c kiu khai bo container, dng lu danh sch cc ti nguyn hoc cc kiu gi tr. Cc phn t ca 1 container c th l cc ti nguyn URI (c th l blank nodes) hay l cc gi tr literals. RDF nh ngha 3 loi i tng container: Bag, Sequence, v Alternative. - Bag l danh sch khng c th t ca cc ti nguyn hoc cc gi tr. Bag cho php nhng gi tr c th trng lp nhau. - Sequence l danh sch c th t ca cc ti nguyn hoc cc gi tr. Chng hn dng Sequence lu tr cc gi tr theo th t bng ch ci. Sequence cho php nhng gi tr c th trng lp nhau. - Alternative l mt danh sch cc ti nguyn hoc cc gi tr, c dng biu din cc gi tr la chn ca mt thuc tnh. V d: Xt pht biu sauBook with ISBN 978-0-596-15381-6 wrote by Toby Segaran, Colin Evans, Jamie Taylor" C m hnh RDF l

Ta biu din di dng c php RDF/XML nh sau:

3.4. RDF CollectionRDF Collection cho php khai bo mt tp hp ng, tng t mt danh sch, c phn t u (rdf:first), phn t k (rdf:rest) v phn t cui (rdf:nil). V d: Xt pht biu sau Book with ISBN 978-0-596-15381-6 wrote by Toby Segaran, Colin Evans, Jamie Taylor" C m hnh RDF l

RDF / XML cung cp mt cch nh ngha m t mt tp hp, bng cch s dng mt thuc tnh c attribute l rdf:parseType=Collection. Ta c th vit li v d trn mt cch ngn gn hn nh sau:

4. Ontology Thut ng Ontology bt ngun t trit hc, n c s dng nh tn ca mtlnh vc nghin cu v s tn ti ca t nhin, xc nh cc vt th trong t nhin v lm th no m t chng. Chng hn nh quan st th gii thc, xc nh cc i tng v sau nhm chng li thnh cc lp tru tng da trn thuc tnh chung.Tuy nhin, trong nhng nm gn y, Ontology tr thnh mt thut ng cbit n nhiu trong lnh vc khoa hc my tnh v c ngha khc xa so vi ngha ban u ca n. Ontology c xem nh l linh hn ca WebNN. Chng gip con ngi v my c th hp tc, cng nhau lm vic, gip my c th hiu v c kh nng x l thng tin hiu qu. Cc Ontology c pht trin trong lnh vc tr tu nhn to s dng li v chia x tri thc c thun tin hn. u nhng nm 1990, Ontology tr thnh mt ch nghin cu ph bin. Ontology c nghin cu bi mt s cng ng nghin cu tr tu nhn to, bao gm k s tri thc, x l ngn ng t nhin v biu din tri thc. Mt nh ngha chung cho ontology l: Ontology l mt c t hnh thc ca skhi nim ha v mt lnh vc ng dng c th. nh ngha ny nhn mnh hai im chnh: s khi nim ha (conceptualisation) l hnh thc v do cho php suy din bi my tnh; v mt ontology trn thc t c thit k cho mt min ng dng c th no . Cc ontology bao gm cc khi nim (cc lp - classes), cc quan h (cc thuc tnh - properties), cc th hin (instances) v cc tin (axioms).

Hnh V d v OntologyXt v d trn, ta c ba lp Employee, Country v Publication, trong lp Employee c 2 thc th LeVanSon v PhanHuyKhanh, c hai thc th ny c quan h ng nghip vi nhau. LeVanSon c thuc tnh l isCitizenOf thc th Vietnam, v thuc tnh hasWritten vi thc th NetworkProgramming.4.1.Cc thnh phn ontologyCc ontology hin nay u c nhiu im tng t v mt cu trc, bt k ngn ng c dng biu din. Hu ht cc ontology u m t cc i tng (thc th), lp (khi nim), thuc tnh v cc quan h.4.1.1 Thc thThc th (instance) l phn c bn ca mt ontology. Cc thc th trong mt ontology c th bao gm cc thc th ri rc nh con ngi, con vt, xe, nguyn t, hnh tinh, trang web, cng nh cc i tng tru tng nh con s v t.4.1.2 LpLp (class) l nhng nhm, b hoc tp hp cc i tng. Lp c th phn loi cc thc th, cc lp khc, hay mt t hp ca c hai. Mt lp c th cng gp nhiu lp hoc c gp vo lp khc; mt lp xp gp vo lp khc c gi l lp con (hay kiu con) ca lp gp (hay kiu cha). Quan h xp gp c dng to nn mt cu trc phn cp cc lp, thng thng c mt lp tng qut ln nht . Kt qu l tnh k tha ca cc thuc tnh t lp cha n lp con. Mt s v d ca lp:Person, lp ca tt c con ngi, hay cc i tng tru tng c th c m t bi cc tiu chun lm mt con ngi.Vehicle, lp ca tt c xe c, hay cc i tng tru tng c th c m t bi cc tiu chun lm mt chic xe.Car, lp ca tt c xe hi, hay cc i tng tru tng c th c m tbi cc tiu chun lm mt chic xe hi.Class, biu din lp tt c cc lp, hay cc i tng tru tng c th c m t bi cc tiu chun lm mt lp.Thing, biu din lp tt c mi th, hay cc i tng tru tng c th c m t bi cc tiu chun lm mt th g (v khng phi khng-l-g c).5.1.3 Thuc tnh Cc thc th trong mt ontology c th c m t bng cch lin h chng vi nhng th khc, thng l cc c im ring hay b phn gi l thuc tnh. Mt thuc tnh c th l mt lp hay mt c th. Kiu ca i tng v kiu ca thuc tnh xc nh kiu ca quan h gia chng. Mt quan h gia mt i tng v mt thuc tnh biu din mt s kin c th cho i tng m n c lin h. Cc ontology ch mang y ngha nu cc khi nim c lin h vi cc khi nim khc (cc khi nim u c thuc tnh). Nu khng ri vo trng hp ny, th hoc ta s c mt phn loi (nu cc quan h bao hm tn ti gia cckhi nim) hoc mt t in c kim sot. Nhng th ny u hu ch nhng khng c xem l ontology.4.1.4. Quan hCc thc th trong mt min ontology c quan h s cho bit cc thc th lin h vi thc th khc nh th no. Quan h l ca mt loi (hay lp) c th ny ch r trong ng cnh no thc th c lin h vi thc th khc trong ontology.Phn ln sc mnh ca ontology nm kh nng din t quan h. Tp hp cc quan h cng nhau m t ng ngha ca domain. Tp cc dng quan h c s dng (lp quan h) v cy phn loi th bc ca chng th hin sc mnh din t ca ngn ng dng biu din ontology.S xut hin ca quan h l lp con ca to ra mt cu trc phn cp th bc; dng cu trc cy ny (hay tng qut hn, l tp c th t tng phn) m t r rng cch thc cc i tng lin h vi nhau. Trong cu trc ny, mi i tng l con ca mt lp cha (Mt s ngn ng gii hn quan h l lp con ca trong phm vi mt cha cho mi nt, nhng a s th khng nh th).Mt dng quan h ph bin khc l quan h meronymy, gi l b phn ca, biu din lm th no cc i tng kt hp vi nhau to nn i tng tng hp.Nu a quan h meronymy vo ontology ny, ta s thy rng cu trc cy n gin v nh nhng trc s nhanh chng tr nn phc tp v cc k kh hiu. iu ny khng kh l gii; mt lp no c m t rng lun lun c mt thnh vin l b phn ca mt thnh vin thuc lp khc th lp ny cng c th c mt thnh vin l b phn ca lp th ba. Kt qu l cc lp c th l b phn ca nhiu hn mt lp. Cu trc ny c gi l th chu trnh c hng.Ngoi nhng quan h chun nh l lp con ca v c nh ngha l b phn ca, ontology thng cha thm mt s dng quan h lm trau chut hn ng ngha m chng m hnh ha. Ontology thng phn bit cc nhm quan h khc nhau. V d nhm cc quan h v:Quan h gia cc lpQuan h gia cc thc thQuan h gia mt thc th v mt lpQuan h gia mt i tng n v mt tp hpQuan h gia cc tp hp.Cc dng quan h i khi c th chuyn ngnh v do ch s dng lu tr cc dng s kin c th hoc tr li cho nhng loi cu hi c th. Nu nh ngha ca dng quan h c cha trong mt4.2. Vai tr cua ontogogyVi ngha v cu trc nh trn, Ontology tr thnh mt cng c quan trng trong lnh vc. Web ng ngha. C th k ra mt s li ch ca Ontology nh: chia s nhng hiu hiu bit chung v cc khi nim, cu trc thng tin gia con ngi hoc gia cc h thng phn mm: y l vai tr quan trng nht ca mt Ontology, khng nhng trong lnh vc Web ng ngha m cn trong nhiu ngnh v lnh vc khc. V phng din ny, c th hnh dung Ontology ging nh mt cun t in chuyn ngnh, cung cp v gii thch cc thut ng cho ngi khng c cng chuyn mn khi c yu cu. Khng ch c s dng bi con ngi, Ontology cn hu ch khi cn s hp tc gia cc h thng phn mm. Ly v d, Open Biological l b Ontology ni ting c pht trin bi trng i hc Stanford nhm cung cp cc thut ng mt cch y trong ngnh sinh vt hc. Ontology ny hin c tch hp vo mt s ng dng Web trn Internet. Sau , mt phn mm tra cu hoc dy sinh hc trn my tnh c th kt ni vi cc ng dng Web trn ly thng tin cho mc tiu ch gii. Cho php ti s dng tri thc: y l mt vn kh v l mc tiu nghin cu quan trng trong nhng nm gn y. N lin quan n bi ton trn hai hay nhiu Ontology thnh mt Ontology ln v y hn. Nhng vn y l tn cc khi nim c nh ngha trong cc Ontology ny c th ging nhau trong khi chng c dng m t cc loi vt hon ton khc nhau. Tuy nhin cng c th c trng hp ngc li, khi tn cc khi nim khc nhau nhng cng m t mt s vt. Ngoi ra, lm th no b sung cc quan h, thuc tnh c sn vo mt h thng mi cng lm cho vn tr nn phc tp. Cho php tri thc c lp vi ngn ng: y cng l vn lin quan n lnh vc ti s dng tri thc ni trn, tuy nhin bi ton ca n l lm th no mt h thng Ontology c th c dng bi cc ngn ng ca cc quc gia khc nhau m khng phi xy dng li. Gii php m Ontology mang li l cho php tn cc khi nim v quan h trong Ontology mi tham kho cc khi nim, nh ngha ca mt h thng Ontology chun thng c xy dng bng ting Anh. iu ny c th s ph v phn no ro cn v mt ngn ng khi m kt qu tm kim s khng b gn trong t kha v ngn ng m n s dng. Ngoi ra, Ontology c th s tr thnh hng i mi cho mt lnh vc quen thuc l dch ti liu t ng. C th ni nh vy, bi ng ngha cc t vng trong vn bn s c dch chnh xc hn khi c nh x vo ng ng cnh ca n. Cho php tri thc tr nn nht qun v tng minh: cc khi nim khc nhau trong mt hay nhiu lnh vc c th c th cng tn v gy nhp nhng v ng ngha, tuy nhin khi c a vo mt h thng Ontology th tn mi khi nim l duy nht. Mt gii php cho vn ny l Ontology s s dng cc tham kho URI lm nh danh tht s cho khi nim trong khi vn s dng cc nhn gi nh bn trn thun tin cho ngi dng. Cung cp mt phng tin cho cng vic m hnh ha: Ontology l mt tp cc khi nim phn cp c lin kt vi nhau bi cc quan h. C bn mi khi nim c th xem nh l mt lp, m i tng ca lp cng cc quan h gp phn to nn cu trc ca bi ton hay vn cn gii quyt. Cung cp mt phng tin cho vic suy lun: hin nay, mt s ngn ng Ontology tch hp lp Ontology suy lun (Ontology Inference Layer) bn trong cho mc ch suy lun logic trn tp quan h gia cc i tng trong h thng. 4.3. Xy Dng Ontology C nhiu phng php khc nhau xy dng mt Ontology, nhng nhn chung cc phng php u thc hin hai bc c bn l: xy dng cu trc lp phn cp v nh ngha cc thuc tnh cho lp. Trong thc t, vic pht trin mt Ontology m t min cn quan tm l mt cng vic khng n gin, ph thuc rt nhiu vo cng c s dng, tnh cht, quy m, s thng xuyn bin i ca min cng nh cc quan h phc tp trong . Nhng kh khn ny i hi cng vic xy dng Ontology phi l mt qu trnh lp i lp li, mi ln lp ci thin v tinh ch dn sn phm ch khng phi l mt quy trnh khung vi cc cng on tch ri nhau. Ngoi ra, cng vic xy dng Ontology cng cn phi tnh n kh nng m rng min quan tm trong tng lai, kh nng k tha cc h thng Ontology c sn, cng nh tnh linh ng Ontology c kh nng m t tt nht cc quan h phc tp trong th gii thc. Ni dung chng ny s cp n mt s nguyn tc c bn ca vic xy dng Ontology qua cc cc cng on c th sau y: Xc nh min quan tm v phm vi ca Ontology. Xem xt vic k tha cc Ontology c sn. Lit k cc thut ng quan trng trong Ontology. Xy dng cc lp v cu trc lp phn cp. nh ngha cc thuc tnh v quan h cho lp. nh ngha cc rng buc v thuc tnh v quan h ca lp. To cc thc th cho lp. Bc 1, Xc nh min quan tm v phm vi ca Ontology: Ging nh mi cng on c t khc, c t Ontology bt u bng vic tr li nhng cu hi mang tnh phn tch nhn din chnh xc cc yu cu. Thng thng, cc yu cu i vi mt h thng Ontology l m t min quan tm nhm phc v c s tri thc trong vic gii quyt nhng mc ch chuyn bit. Do , nhng cu hi ny thng l: Ontology cn m t min no? Ontology phc v cho mc ch chuyn bit g? C s tri thc trong Ontology s tr li nhng cu hi g? Ontology nhm vc v i tng no? Ai l ngi s xy dng, qun tr Ontology? Nhn chung, cu tr li cho cc cu hi dng ny c th s thng xuyn thay i trong sut qu trnh lp xy dng mt Ontology. Nht l khi c s thay i v mc ch hoc cn b sung tnh nng trong vic s dng c s tri thc. Tuy nhin, vic tr li chnh xc cc cu hi trn ti mi bc lp s gip gii hn phm vi thc s ca m hnh cn m t v d tr cc k thut s s dng trong qu trnh pht trin. Ly v d, nu d tr kh nng xy ra s khc bit v ngn ng gia ngi pht trin v ngi s dng th Ontology phi c b sung c ch nh x (mapping) qua li cc thut ng gia cc ngn ng khc nhau. Hoc gi s Ontology cn xy dng c chc nng x l ngn ng t nhin, ng dng dch ti liu t ng th cng cn thit phi c k thut xc nh t ng ngha chng hn.Sau khi pht tho phm vi Ontology da trn vic tr li nhng cu hi trn, ngi thit k s tr li cc cu hi mang tnh nh gi, qua tip tc tinh chnh li phm vi ca h thng cn xy dng. Cc cu hi dng ny thng da trn c s tri thc ca Ontology v c gi l cu hi kim chng kh nng (competency question): Ontology c thng tin tr li cho cc cu hi c quan tm trn c s tri thc hay khng? Cu tr li ca c s tri thc p ng c mc , yu cu no ca ngi s dng? Cc rng buc v quan h phc tp trong min quan tm c biu din hp l cha? Bc 2, Xem xt vic k tha cc Ontology c sn: y l mt cng on thng hay s dng gim thiu cng sc xy dng mt Ontology. Bng cch k tha cc Ontology tng t c sn, ngi xy dng c th thm hoc bt cc lp, quan h gia cc lp, thc th.. tinh chnh ty theo mc ch ca mnh. Ngoi ra, vic s dng li cc Ontology c sn cng rt quan trng khi cn s tng tc gia cc ng dng khc nhau. L do l cc ng dng s cn phi hiu cc lp, thc th, quan h.. ca nhau thun tin trong vic trao i hoc thng nht thng tin. Vn xy dng mt Ontology mi bng cch k tha cc h thng c sn lin quan n mt bi ton rt phc tp l trn (merging) cc Ontology. Nh ni trong mc trc, tn cc khi nim c nh ngha trong cc Ontology ny c th ging nhau trong khi chng c dng m t cc loi vt hon ton khc nhau. Trong khi , cng c th xy ra trng hp ngc li, khi tn cc khi nim khc nhau nhng cng m t mt s vt. V mt vn na l lm th no b sung cc quan h, thuc tnh c sn vo mt h thng mi. Tuy nhin, hu ht cc Ontology s dng trong ngnh khoa hc my tnh ni chung v Web ng ngha ni ring u c xy dng trn cc h thng xy dng v qun tr Ontology. C th k tn mt s cng c, chng hn: Sesame, Protg, Ontolingua, Chimaera, OntoEdit, OidEd.. Hin nay, a s cc phn mm ny u h tr chc nng t ng trn cc Ontology cng hoc thm ch khc nh dng vi nhau. Mc d vy, mc no , ngi xy dng cng cn phi kim tra li mt cch th cng, nhng y c l cng khng phi l mt cng vic phc tp. Hin c rt nhiu Ontology c chia s trn Web. C th k ra mt s Ontology ni ting nh: UNSPSC (www.unspsc.org) do Chng trnh pht trin ca Lin Hip Quc hp tc vi t chc Dun & Bradstreet nhm cung cp cc thut ng ca cc sn phm v dch v thng mi. Cc Ontology trong lnh vc thng mi khc nh: RosettaNet (www.rosettanet.org), DMOZ (www.dmoz.org), eClassOwl,.. Open Biological, BioPax trong lnh vc sinh vt hc, UMLS trong lnh vc mng ng ngha, GO (Gene Ontology), WordNet (i hc Princeton).. Bc 3, Lit k cc thut ng quan trng trong Ontology: y l bc rt ch hu, lm tin cho hai bc tip theo l xy dng cu trc lp phn cp v nh ngha cc thuc tnh cho lp. Cng on ny bt u bng vic lit k tt c cc thut ng xut hin trong min quan tm (c th ng ngha hoc chng nhau) nh tn khi nim, quan h, thuc tnh.. V d, cc thut ng xut hin trong v d Ontology v sinh vt trong chng trc l: ng vt, thc vt, cy ht kn, chim, th, cng sinh, cnh tranh.. Thng thng, cc thut ng l danh t s tr thnh cc lp, tnh t s tr thnh thuc tnh, cn ng t s l quan h gia cc lp. Bc 4, Xy dng cc lp v cu trc lp phn cp: Nh ni, y l mt trong hai bc quan trng nht ca cng vic xy dng mt Ontology. Nhim v ca bc ny l nh ngha cc lp t mt s thut ng lit k trong bc 3, sau xy dng cu trc lp phn cp theo quan h lp cha-lp con theo cc phng php phn loi cp trong chng 2. Lp v tr cng cao trong cu trc ny s c mc tng qut cng cao. V tr u tin thuc v lp gc, tip theo l cc lp trung gian, v cui cng l lp l. Lp l l lp khng th trin khai c na v ch c biu hin bng cc thc th. Quan h gia thc th ca lp con vi lp cha n trong m hnh phn cp ny l quan h is-a. Ngha l mt thc th ca lp con cng l-mt thc th Nhn chung, c nhiu hng tip cn khc nhau cho vn xy dng cu trc lp phn cp. C th k ra ba hng nh sau: Hng xy dng t trn xung (top-down): bt u bng cc lp c mc tng qut cao nht, sau trin khai dn n lp l. Hng xy dng t di ln (bottom-up): Ngc vi hng xy dng cu trc lp phn cp t trn xung, hng ny bt u bng vic xc nh cc lp c cho l c th nht, sau tng qut ha n khi c lp gc. Cch kt hp (combination): cch ny kt hp c hai hng xy dng trn. u tin chn cc lp ni bt nht trong min quan tm, sau tng qut ha v c th ha cho n khi c cu trc mong mun. Bc 5, nh ngha cc thuc tnh v quan h cho lp: Bn thn cc lp nhn c bc trn ch mi l nhng thut ng phn bit vi nhau bng tn gi. V c bn, chng cha phc v cho vic biu din tri thc. Mun nh vy, cc thuc tnh ca lp cn c nh ngha. Thuc tnh ca lp l cc thng tin bn trong ca lp, m t mt kha cnh no ca lp v c dng phn bit vi cc lp khc. Thuc tnh c chia lm nhiu loi khc nhau: V mt ngha, cc thuc tnh c th c chia lm hai loi: thuc tnh bn trong (intrinsic property) v thuc tnh bn ngoi (extrinsic property). Thuc tnh bn trong m t cc tnh cht ni ti bn trong s vt, v d: cht, lng, cu to.. Trong khi , thuc tnh bn ngoi m t phn biu hin ca s vt, v d: mu sc, hnh dng.. V mt gi tr, cc thuc tnh cng c chia lm hai loi: thuc tnh n (simple property) v thuc tnh phc (complex property). Thuc tnh n l cc gi tr n v d: chui, s.., cn thuc tnh phc c th cha hoc tham kho n mt i tng khc. Mt ch quan trng na trong bc ny l vic mt lp s k tha ton b cc thuc tnh ca tt c cc cha n. Do , cn phi xem xt mt thuc tnh c nh ngha cc lp thuc mc cao hn hay cha. Thuc tnh ch nn c nh ngha khi n l tnh cht ring ca lp ang xt m khng c biu hin cc lp cao hn. Bc 6, nh ngha cc rng buc v thuc tnh v quan h ca lp: Cc rng buc gii hn gi tr m mt thuc tnh c th nhn. Hai rng buc quan trng nht i vi mt thuc tnh l lng s (cardinality) v kiu (type). Rng buc lng s quy nh s gi tr m mt thuc tnh c th nhn. Hai gi tr thng thy ca rng buc ny l n tr (single) v a tr (multiple). Nhng mt s phn mm cn cho php nh ngha chnh xc khong gi tr ca lng s. Rng buc th hai l v kiu. V c bn, cc kiu m mt thuc tnh c th nhn l: chui, s, boolean, lit k v kiu thc th. Ring kiu thc th c lin quan n hai khi nim gi l: min (domain) v khong (range). Khi nim min c dng ch lp (hay cc lp) m mt thuc tnh thuc v. Trong khi , khong chnh l lp (hay cc lp) lm kiu cho gi tr thuc tnh kiu thc th. Ly v d, lp ng vt trong hnh 4.1 c thuc tnh loi thc n thuc kiu thc th (c cy, cn trng..). Lc ny, min ca loi thc n l ng vt, sinh vt.. Cn khong ca n chnh l lp c, cy,..Bc 7, To cc thc th cho lp: y l bc cui cng khp li mt vng lp xy dng Ontology. Cng vic chnh lc ny l to thc th cho mi lp v gn gi tr cho cc thuc tnh. Nhn chung, cc thc th s to nn ni dung ca mt c s tri thc v l vn c quan tm trong lnh vc Web ng ngha. 5. Ngn ng Ontology5.1. RDFschemaRDF: m t cc ngun ti nguyn bng cc lp, cc thuc tnh v cc gi tr, cung cp tnh lin thng gia cc ng dng.Tuy nhin, chng ta cn phi nh ngha cc lp v cc thuc tnh trong cc ng dng chuyn bit. lm c iu ny, chng ta s phi s dng mt phin bn m rng ca RDF, gi l RDFS hay RDF Schema.Ngn ng RDF ch gip cho thng tin c th hin dng b ba theo ng m hnh RDF ch thng tin vn cha th hin g v mt ng ngha. Bi vy, xy dng RDFS l iu cn thit hnh thnh nn ng ngha cho thng tin, l c s xy dng cc cng c tm kim ng ngha. RDFS v RDF c mi lin h tng i gn gi nn i lc ta gi ngn ng ny l RDF/RDFS. RDFs: Cho bit DL c m t trn RDF c din dch nh th no nh ngha t vng cho RDF T chc t vng di dng cy phn cp Kh nng khai bo tng minh cc quan h ng ngha gia cc vocabulary terms

Hnh 4.1 cho chng ta s phn bit gia RDFS vi RDF :

Trong hnh v chng ta thy, tng RDF ch biu din c thng tin dng b ba. n tng RDFS, thng tin c phn loi r rng. Chng hn nh Quan Thanh Tho c kiu l Lecturer v Lecturer l lp con ca Academic Staff v.vV d: Xt lc RDF sau Horse l subclass ca class Animal

Hnh Horse l subclass ca class AnimalTa s dng RDF Schema nh ngha, ch thch cc mi quan h:

Khi lp RDFS l ti nguyn RDF, ta c th dng rdfs:Class thay v dng rdf:Description v b qua thng tin trong rdf:type nh sau:

5.1.1 nh ngha lp (class)Cc ti nguyn trn Web c th chia thnh cc nhm gi l class. Cc thnh vin ca nhm c xem nh l th hin ca lp . Thng qua cc nh danh URI, cc ti nguyn c truy xut v c th c m t bng cc RDF properties. Thuc tnh rdf: type c s dng ch ra mt resource l mt th hin ca mt class. 5.1.2 nh ngha thuc tnh (property)RDF Schema cung cp mt b t vng m t lm th no m cc thuc tnh v lp c th c s dng cng nhau trong RDF. Thuc tnh quan trng nht c s dng trong trng hp ny l rdfs:range v rdfs:domain

Cch s dng rdfs:rangeThuc tnh rdfs:range dng ch gi tr ca mt thuc tnh l th hin ca mt lp. V d nh, nu cng ty example.org mun ch rng thuc tnh ex:author c gi tr l th hin ca lp ex:Person, ta s vit pht biu RDF nh sau: ex:Person rdf:type rdfs:Class . ex:author rdf:type rdf:Property . ex:author rdfs:range ex:Person . Pht biu ny ch rng ex:Person l mt lp, ex:author l mt thuc tnh, v thuc tnh ex:author c object l thc th ca lp ex:Person. Tuy nhin mt thuc tnh c th c nhiu rdfs:range, nh v d sau: ex:hasMother rdfs:range ex:Female . ex:hasMother rdfs:range ex:Person .Thuc tnh rdfs:range c th c s dng ch ra gi tr ca kiu typed literal ex:age rdf:type rdf:Property .ex:age rdfs:range xsd:integer .Cch s dng rdfs:domainThuc tnh rdfs:domain c s dng ch rng mt thuc tnh l thuc tnh ca mt lp no . V d nh, cng ty example.org mun thuc tnh ex:author l thuc tnh ca lp ex:Book , ta c pht biu sau:ex:Book rdf:type rdfs:Class . ex:author rdf:type rdf:Property . ex:author rdfs:domain ex:Book .V mt thuc tnh cng c nhiu thuc tnh rdfs:domain khcexterms:weight rdfs:domain ex:Book . exterms:weight rdfs:domain ex:MotorVehicle .5.1.3 Lut suy din ng ngha trong RDFSC 6 trng hp suy din theo cc cp loi lp, thuc tnh, lp con, thuc tnh con, min (domain), di (range)Trng hp 1: Suy din v loi ca lp (type) IF (c2, subClassOf, c1) AND (x, type, c2) THEN (x, type, c1)V d:IF (Man, subClassOf, Person)AND (Tom, type, Man)THEN (Tom, type, Person)Trng hp 2: Suy din v thuc tnh ca lp (Property) IF (p2, subPropertyOf, p1)AND (x, p2, y)THEN (x, p1, y) - V d:IF (author, subPropertyOf, creator)AND (Tom, author, Report2010)THEN (Tom, creator, Report2010)Trng hp 3: Suy din v lp con ca lp (subclassOf) IF (c2, subClassOf, c1)AND (c3, subClassOf, c2) THEN (c3, subClassOf, c1)- V d:IF (Person, subClassOf, Animal) AND (Man, subClassOf, Person) THEN (Man, subClassOf, Animal)Trng hp 4: Suy din v thuc tnh con ca thuc tnh (subPropertyOf) IF (p2, subPropertyOf, p1)AND (p3, subPropertyOf, p2) THEN (p3, subPropertyOf, p1)- V d:IF (parent, subPropertyOf, ancestor)AND (father, subPropertyOf, parent) THEN (father, subPropertyOf, ancestor) Trng hp 5: Suy din trong min (domain) IF (p1, domain, c1)AND (x, p1, y) THEN (x, type, c1) - V d:IF (author, domain, Human) AND (Tom, author, Report2010) THEN (Tom, type, Human)Trng hp 6: Suy din trong dy gii hn (range) IF (p1, range, c1)AND (x, p1, y) THEN (y, type, c1)- V d:IF (author, range, Document) AND (Tom, author, Report2010) THEN (Report, type, Document)5.4.1 V d v xy dng ontology vi RDFS Chng ta s dng c php c bn sau biu din cho mt pht biu (statement): {subject,predicate,object} Nu c nhiu hn mt thuc tnh cho mt ch th th: {subject, {predicate1, object1} {predicate2, object2} } Nu c nt trng (blank node) th biu din nh sau: {subject, predicate, {predicate-of-bnode,object-of-bnode} } Mt ti nguyn bt u bi du # chng hn #resource_1 th c ngha l ti nguyn c khai bo trong cng mt ti liu m chng ta ang xy dng ontology. Sau ny mun s dng ti nguyn th ta dng #resource _1 ch khng cn phi ly URI ca n cho phc tp, kh nhn. By gi chng ta s i vo xy dng mt Ontology n gin, Ontology ny s xy dng tm gn s nh hnh 4.1: {rdfs:Class {rdf:ID,"StaffMe{rdfs:Class}//Khai bo khng tng minh, ko nn dng {rdf:resource,http://www.semantic.vn/2009/01/rdf-schema#StaffMember"}}{rdfs:Class {rdf:about,"AcademicStaff"} {rdfs:subClassOf, "# StaffMember"} } {rdfs:Class {rdf:about,"Lecturer"} //Khai bo tng minh {rdfs:subClassOf, #AcademicStaff} } {rdfs:Class {rdf:ID,"Course"} {rdf:resource, http://www.semantic.vn/2009/01/rdf-schema#Course"} } {rdf:Property { rdf:ID,"phone"} {rdfs:domain, #staffMember} {rdfs:range ,"http://www.semantic.vn/2009/01/rdf-schema#Literal"} } {rdf:Property { rdf:ID,"ID"} {rdfs:domain, #staffMember} {rdfs:range ,"http://www.semantic.vn/2009/01/rdf-schema#Literal"}{rdf:Property { rdf:ID,"involve"} {rdfs:domain, #Course} {rdfs:range ,#AcademicStaff} } {rdf:Property { rdf:ID,"isTaughtBy"} {rdfs:domain, #Course} {rdfs:range ,#AcademicStaff} {rdf:subPropertyOf, involve} } T Ontology c xy dng nh trn ta c th v ra s phn cp cc ti nguyn nh sau : StaffMember Academic Staff Lecturer Course Nhn s ta thy c hai ti nguyn l StaffMember v Course. Cc lp AcademicStaff v Lecturer ch l tha k t StaffMember.5.2. OWL( Ontology Web LanguageOWL l ngn ng ontology kh mnh, n ra i sau RDFS nn bit k tha nhng li th ngn ng ny ng thi b sung thm nhiu yu t gip khc phc c nhng hn ch RDFS. OWL gip tng thm yu t logic cho thng tin v kh nng phn loi, rng buc cng nh lng s tng i mnh. Chng ta hy tm hiu s qua cc lp v thuc tnh ca OWL thy c nhng u im OWL so vi RDFS Classes Properties owl:AllDifferentowl:allValuesFrom owl:TransitiveProperty owl:Class owl:backwardCompatibleWith owl:inverseOf owl:DataRangeowl:cardinality owl:maxCardinality owl:DataTypeProperty owl:complementOf owl:minCardinality owl:DeprecatedPropertyowl:distinctMembers owl:oneOf owl:DeprecatedClass owl:differentFrom owl:onProperty owl:FunctionalProperty owl:disjointWith owl:priorVersion owl:InverseFunctionalProperty owl:equivalentClass owl:sameAs owl:Nothing owl:equivalentProperty owl:sameIndividualAs owl:ObjectProperty owl:hasValue owl:someValuesFrom owl:Ontology owl:imports owl:subClassOf owl:Restriction owl:incompatiblewith owl:unionOf owl:SymmetricProperty owl:intersectionOf owl:versionInfo Trong OWL c thm mt s thuc tnh h tr suy lun v rng buc. *H tr suy lun Tnh cht bt cu: Nu nh chng ta c mt lp thuc tnh contain v gn cho n thuc tnh owl: transitivePropertive th thuc tnh contain ny s c tnh cht bt cu. Gi s ta c thng tin A contain B v B contain C, th h thng s t suy lun ra mt thng tin khc l A contain C. V y l biu din thuc tnh contain trong OWL: {owl:TransitiveProperty {rdf:ID,"contain"} } Tnh cht o ngc: Nu A c thuc tnh hasParent l B, th suy ra B c thuc tnh hasChild l A. {owl:OjectProperty {Rdf:ID, hasChild} {owl:inverseOf, #hasParent} } *H tr rng buc Rng buc kiu: Gi s ta c lp Human, tha k t hai lp ny l Man v Woman. Ta mun mt i tng thuc lp Man th khng th thuc lp Woman v ngc li. {owl :Class {rdf :about, #Man} {owl :disjointWith, #Woman} } Ta mun mt ngi th ch c mt cha v mt m. Tc thuc tnh hasParent th lun gn s lng l 2. {owl :Restriction {owl :onProperty, #hasParent} {owl :cardinality, 2} } Trn y l mt vi v d m trong RDFS khng th lm c. R rng OWL c nhiu u im hn trong vic xy dng h thng ontology thng minh v c phn loi tt. Vi nhng c im , OWL ngy nay tr thnh ngn ng ontology chnh thc cho vic xy dng v pht trin cc h thng Semantic Web.C 3 loi OWL:-OWL y : khng gii hn vic cc t vng c xy dng nh th no.-OWL DL (Description Logic): s dng logic m t dn n cc suy lun-OWL Lite: dng n gin nht ci t OWL5.3 DAML + OIL DAML + OIL l kt qu t hai d n nghin cu c lp vi nhau l DAML (DARPA Agent Markup Language) v OIL (Ontology Inference Layer) nhm khc phc nhng hn ch v kiu d liu trong cc ngn ng Ontology trc l RDF, RDFS. DAML + OIL (gi tt l DAML) l ngn ng nh du cho cc ti nguyn trn Web, c h tr suy lun. Ngn ng ny c xy dng c k tha t cc chun ca W3C nh XML, RDF, RDFS,.. Mt s im ng ch ca ngn ng ny l: Cho php gii hn cc kiu d liu c nh ngha trong XML Schema hay bi ngi dng. Trong DAML, mt thuc tnh c th nhn gi tr trn nhiu khong khc nhau, to nn tnh uyn chuyn trong vic m t d liu. Cho php nh ngha thuc tnh unique xc nh cc i tng. Cho php m t cc quan h nh hon i v bc cu. DAML sau tip tc tr thnh nn tng cho mt ngn ng Ontology khc l OWL. DAML v c bn rt ging vi OWL (ngoi tr tn mt s t thut ng, c php c sa i), tuy nhin kh nng m t cc rng buc km hn. Theo thng k, c khong 5 triu pht biu DAML t hn 20,000 Website trn Internet vo nm 2002. 6. Cng C Xy Dng v Qun Tr Ontology 6.1 Gii thiu V mt l thuyt, ngi xy dng v qun tr Ontology c th khng cn cc cng c h tr, thay vo c th thc hin trc tip bng cc ngn ng. Tuy nhin, cch th hai s khng kh thi khi Ontology c kch thc ln v cu trc phc tp. Thm vo , vic xy dng v qun tr Ontology khng ch i hi vic to cu trc lp phn cp, nh ngha cc thuc tnh, rng buc.., m cn bao hm vic gii quyt cc bi ton lin quan trn n. C rt nhiu bi ton lin quan n mt h thng Ontology nh: Trn hai hay nhiu Ontology. Chun on v pht hin li. Kim tra tnh ng n v y . nh x qua li gia cc Ontology. Suy lun trn Ontology. Sao lu v phc hi mt Ontology. Xa, sa v tinh chnh cc thnh bn trong Ontology. Tch bit Ontology vi ngn ng s dng (DAML, OWL,..). Nhng kh khn trn khin cc cng c tr thnh mt thnh phn khng th thiu, quyt nh n cht lng ca mt h thng Ontology. Hin c rt nhiu cng c c kh nng h tr ngi thit k gii quyt nhng bi ton lin quan. C th k ra mt s nh: Sesame, Protg, Ontolingua, Chimaera, OntoEdit, OidEd.. Ni dung chng ny s cp n hai cng c l Protg v Chimaera. Cc cng c cn li s c cp trong phm vi ca mt bi vit khc. 6.2 Protg Protg l b phn mm m ngun m Java ni ting. Protg c nghin cu v pht trin t nm 1998 bi nhm nghin cu ca Mark Musen, H. Stanford nhm qun l cc thng tin trong lnh vc sinh y hc. y l d n c nhn c s quan tm v ti tr t rt nhiu t chc, trong c B Quc Phng M. M ngun Protg c th c tm thy ti website: http://smi-protege.stanford.edu/repos/protege/owl/trunk.Hin ti, Protg c phin bn 3.4. Phin bn Beta 4.0 ang c pht trin v th nghim song song bi s hp tc gia CO-ODE (Cooperative Ontologies Programme) v i hc Stanford. Cc u im ca Protg l: H tr y ba phin bn ca ngn ng OWL l OWL-Full, OWL-Lite v OWL-DL. Nh s dng m hnh hng i tng ca ngn ng Java, Protg t ra rt hiu qu trong vic m hnh cc lp, thc th, quan h.. Giao din thit k trc quan c tnh tng tc cao. Ngi s dng c th nh ngha cc thnh phn ca Ontology trc tip t cc form. Cho php biu din trc quan Ontology di dng cc s . Cho php xy dng Ontology t nhiu ngun khc nhau. Protg t ng lu mt bn tm ca Ontology. Nu c li pht sinh trong qu trnh thao tc th Ontology c s t ng c phc hi. Ngi thit k cng c th chuyn qua li gia hai bn Ontology ny bng chc nng Revert to a Previous Version v Active Current Version. Cung cp chc nng tm kim li, kim tra tnh nht qun v y ca Ontology. s dng, ngi thit k chn chc nng Run Ontology Test v Check Consistency. Cho php cc lp v thuc tnh ca Ontology ny c th c s dng trong mt Namespace khc m ch cn s dng cc URL tham kho. s dng, chn chc nng Move Resource to Namespace. H tr suy lun trc tip trn Ontology da trn Interface chun DL Implementation Group (DIG). H tr sinh m t ng. Protg cho php chuyn Ontology thnh m ngun RDF/XML, OWL, DIG, Java, EMF Java Interfaces, Java Schema Classes.. Cc m ny c th c nhng trc tip vo ng dng v l u vo cho cc thao tc trn Ontology khi cn. Cung cp y chun giao tip cho cc Plug-in. Tuy nhin, Protg cng th hin mt s hn ch nh khng cho php truy vn tng phn mt c s tri thc dn ti vic khng qun l hiu qu cc c s tri thc c kch thc ln, hoc cha h tr kt ni trc tip vi mt s h qun tr c s tri thc ph bin nh Sesame,..7. Cc dch v Web ng nghaCc dch v Web5 (Web Services - WS) cung cp mt nn tng cho kin trc phn mm mi c gi l Kin trc hng Dch v (Service-Oriented Architecture SOA). Kiu kin trc ny pht trin mt cch nhanh chng v tr thnh nh mt gii php cho nhng kh khn trong vic pht trin phn mm nh: phn mm s dng li, lp trnh phn tn v cc mi trng ng dng a dng. c bit, Ngn ng M t Cc dch v Web (WSDL) tip tc l mt phn quan trng ca WS c chuNn ha bi W3C.WS cho php chng ta truy cp cc ng dng lin quan, cho d vy cc qu trnh nh khm ph (discovery), bin tp (composition) v thc thi (execution) WS vn cn s h tr t s tng tc ca con ngi. y chnh l im m ta cn WebNN h tr WS vi cc ontology nh l cc gi tr gia tng (Hnh 4). Vic kt hp sc mnh ca WS v cc gi tr gia tng ca WebNN s cho mt nn tng c th cho cc ng dng doanh nghip.

Hin c rt nhiu hot ng din ra song song hin thc ha mc tiu ny. Chng trnh Cc Cng ngh cho X hi Thng tin (Information Society Technologies) ca y ban Chu u6 khi ng nhiu d n v WS s dng cc khi nim WebNN.Mt s cc vn thch thc cn c cc d n ny thc hin l: To lp cc ontology cho vic m t v phn loi WS; S tin cy v chng thc cc dch v web ng ngha (Semantic Web Services); Biu din tri thc cho cc dch v web ng ngha; Ng ngha cho s y thc dch v v kt hp tri thc.8. Cc ng dng ca Web ng ngha WebNN cho php cc ng dng lm cu ni gia nhng nhu cu ca ngi s dng v cc ti nguyn thng tin sn c. iu ny s thit lp mt c s cho vic pht trin cc ng dng. Trong thi gian gn y, cc tip cn WebNN tr nn n nh hn v cc thnh phn thit yu c cung cp theo cc chun. Bc tip theo s l ng dng cng ngh ang pht trin mnh ny vo cuc sng hng ngy ca chng ta.Mt s th nghim cc ng dng da trn ng ngha u tin c ci t thnh cng v rt nhiu cc ng dng na ang c pht trin. Do min ng dng rng ca WebNN, nn ta c th c c rt nhiu cc ca s dng ca WebNN cho cc lnh vc khc nhau. Hu ht cc nh nghin cu WebNN u c chung mt tho thun ngm vi nhau trnh nhc n nhng iu thuc v tr tu nhn to (TTNT). D rng WebNN c th ri vo mt vi vn ca TTNT nhng mt iu chc chn rng n khng phi l mt th h k tip ca TTNT. Chng ta khng th trng i WebNN s l cha kho cho mi vn . Mt gii php tt ca WebNN c c bi ngun gc chc chn ca n l mt ontology c thit k t m.Mt s ng dng mang tnh thch thc m chng c th lm thay i cch m chng ta s dng my tnh: Cc b nh C nhn Tng cng l mt ng c vin tim nng cho cc ng dng WebNN. c rt nhiu n lc ca cc nhm nghin cu, cc d n cho vn ny. Tch hp tri thc ca th gii vo my tnh desktop (semantic desktop) theo mt cch c th truy nhp d dng v hiu qu. Tch hp cc dch v web ng ngha vo cc ng dng thng c s dng (cc trnh th in t, cc trnh duyt web,...) cung cp nhiu hn tnh hot ng lin thng trn web cng nh gia cc ng dng. ng dng WebNN vo thng mi in t, c bit l cc nghin cu lin quan n Qun l tin trnh nghip v (Business Process Management) trong thng mai in t v B2B (business-to-business). y l mt trong nhng ng dng mi ca WebNN nhm lm giu ng ngha cho cc tin trnh nghip v trong mi trng cng tc doanh nghip.9. Ngn ng truy vn RDFProtocol And RDF Query Language (SPARQL) truy cp d liu RDFNh chng ta bit RDF l mt cch m t thng tin v cc ti nguyn Web mt cch linh ng . N c s dng m t nhiu loi thng tin v d nh thng tin v c nhn, v h thng mng ton cu, meta-data v multimedia nh music v hnh nh cng nh l cung cp mt phng tin tch hp cc ngun ti nguyn khc. Vi mt lng thng tin qu ln nh vy, lm th no d liu c th c truy vn nhanh chng v chnh xc? T chc W3C pht trin mt ngn ng chun truy vn d liu RDF vi vic cung cp nhiu chc nng cho cc developer v end users cch vit v thc thi mt cu truy vn . K ny m t ngn ng truy vn Protocol And RDF Query Language (SPARQL) truy cp d liu RDF c pht trin bi nhm RDF Data Access Working Group-mt phn trong hot ng ca Semantic Web.Mt RDF Graph l mt tp cc triple, mi triple bao gm b ba subject, predicate v object. Nhng triple ny c th n t nhiu ti nguyn khc nhau. V d nh: chng c th n t mt ti liu RDF, chng c th c suy ra t cc RDF triple khc hoc l chng c th l s m t RDF ca cc d liu c lu tr t cc nh dng khc nh XML hay l t mt c s d liu quan h. SPARQL l mt ngn ng truy cp thng tin t cc th RDF. N cung cp cc tnh nng sau: -Trch thng tin trong cc dng ca URI, cc blank node v cc plain hay typed literals. -Trch thng tin t cc th con. -Xy dng mt th RDF mi da trn thng tin trong th truy vn9.1. To mt cu truy vn n ginMt cu truy vn bao gm 2 mnh , mnh SELECT v mnh WHERE. Mnh SELECT nh danh cc bin m ng dng quan tm v mnh WHERE bao gm cc triple pattern. Mt triple pattern l mt RDF triple nhng mi thnh phn (subject, predicate hay object) u c th l mt bin truy vn. Mt basic graph pattern l mt tp cc triple pattern. Ngn ng SPARQL da trn nn tng so snh cc graph pattern. Graph pattern n gin nht l cc triple pattern. Kt qu ca cu truy vn l tt c cc gii php m mt cu truy vn c th ph hp vi th c truy vn. Mt cu truy vn c th c khng,mt hay nhiu kt qu.S dng cu truy vn sau ti trang web: http://dbpedia.org/sparql tm cc quc gia trong thm lc a c dn s ln hn 15 triu dn.PREFIX type: PREFIX prop: SELECT ?country_name ?populationWHERE {?country a type:LandlockedCountries ;rdfs:label ?country_name ;prop:populationEstimate ?population .FILTER (?population > 15000000 && langMatches(lang(?country_name), "EN")) .} ORDER BY DESC(?population)Ngn ng SPAQL ta c th chn la kiu bin tr v di dng XML hay l RDF.Kt qu ca php truy vn trn l:

9.2. C php ca cu truy vnCc gi tr c t trong du dng ch mt nh danh URI. Cc gi tr c t trong du ( ) l cc gi tr literal. Bin trong ngn ng truy vn c gi tr ton cc. Bin thng bt u vi k t ? hay k t $ ch mt bin. SPARQL cung cp mt c ch vit tt. Tip u ng (prefix) c th c nh ngha v mt QName s cung cp mt dng vit lm cho URI c th ngn gn.Sau y l mt cch vit tt cho triple patternPREFIX dc: SELECT ?titleWHERE { dc:title ?title }Ta c th s dng mt cch vit tt :PREFIX dc: PREFIX : SELECT $titleWHERE { :book1 dc:title $title }Blank nodeBlank node c th xut hin trong mt mu truy vn. N gi vai tr nh mt bin, d khng c cp trong kt qu ca cu truy vn hay bt k ni no trong graph pattern.Blank node trong cc cu truy vn khc vi vi cc blank node trong d liu, do blank node trong mt graph pattern khng tng ng vi mt blank node trong d liu thng qua mt nhn blank node.V d:- D liu@prefix foaf: ._:a foaf:name "Chuong Nguyen" ._:a foaf:mbox .- Truy vnPREFIX foaf: SELECT ?mboxWHERE{ ?x foaf:name "Chuong Nguyen" .?x foaf:mbox ?mbox }- Kt qumbox mailto:nvchuong2.0@gmail.comDanh sch predicate-ObjectCc triple pattern vi mt subject chung c th c vit sao cho subject ch c vit 1 ln, mi triple pattern s c cch nhau bi du ;?x foaf:name ?name ;foaf:mbox ?mbox .Cch vit trn tng t vi cch vit:?x foaf:name ?name .?x foaf:mbox ?mbox .