Will the Semantic Web Change Education ?

To say that the Web has affected many societies and cultures is to understate its impact along several dimensions. The Web is a technology which not only affects, but in some sense encompasses societies, cultures, and certainly institutions. Higher education -at least in the cluster of ways in which it is practiced in the US, the EU, and Japan -is one such bundle of social institutions affected and encompassed by the Web. While it is possible to overstate or mis-state the Web's effect, whether on higher education or on other institutional clusters, the encompassing reach of the technology, used in every country on Earth by literally tens of millions of users, makes it clear that the Web truly has a revolutionary effect. However, exploring what the Web has affected and continues to effect is a necessary element of any accurate estimation of how the newly emerging Semantic Web may, in its turn, effect societies, cultures, and institutional clusters like higher education. C o m m e n t a r i e s : All JIME articles are published with links to a commentaries area, which includes part of the article’s original review debate. Readers are invited to make use of this resource, and to add their own commentaries. The authors, reviewers, and anyone else who has ‘subscribed’ to this article via the website will receive e-mail copies of your postings. C l a rk, K., Parsia, B. and He n d l e r, J. (2004). Will the Semantic Web Change Education? Journal of In t e r a c t i ve Media in Education, 2004 (3) [ w w w j i m e . o p e n . a c . u k / 2 0 0 4 / 3 ] Published 21 May 2004 ISSN: 1365-893X Kendall Clark, Bijan Parsia, and Jim He n d l e r, Ma ryland In f romation and Ne t w o rk Dy n a m i c s L a b o ra t o ry, Un i versity of Ma ryland, http://www. m i n d l a b. u m d . e d u Page 1 1 . Hypertext: Beyond Te x t T h e re are many models of hypertext, each of which has various richnesses and a f f o rdances and degrees of expre s s i v i t y. The Web's hypertext model is a re l a t i ve l y i m p overished one, especially as compared with models which include bidire c t i o n a l links, re s o u rce versioning, default genre and document stru c t u res, guided paths t h rough re s o u rces, re s o u rce and re s o u rc e p a rt annotations, and so on. [The De x t e r Hy p e rtext Re f e rence Mo d e l1; Go p h e r2; Xanadu3; Se rving Information to the We b with Hy p e r G4] Despite, or some would argue because of, the Web's simple model, it has had a greater impact than any of the more expre s s i ve technologies that p roceeded it. The primary reason that the Web has been so much more widely accepted is that it was designed to allow two key capabilities: openness and scalability. The first re s u l t e d f rom a conscious design decision that one should be able to link to other people's re s o u rces without any need for permission, and that one could make a re s o u rc e a vailable on one's own server in such a way that others could link to it. The second is achieved by the Web's capability to take advantage of a network effect: If I cre a t e something, and you create something, we can point to each other's re s o u rces, rather than having to duplicate re s o u rces. This is the Web in the World Wide Web -and the network effect is where most of the power comes from -it is often easier to c reate content (with pointers) on the Web than to duplicate that information e l s ew h e re. Thus, the one of the fundamental design goals of the Web was to use a re l a t i vely impoverished hypertext model that was open and scalable, rather than to use or develop a more expre s s i ve hypertext model that was more re s t r i c t i ve . 1 . 1 Academic Practice One way to judge the impact of the Web on higher education is by judging the distance between text and hypertext, particularly with re g a rd to academic practice. Historically the various printed page technologies and the unive r s i t y, as well as the re s e a rch library, have been co-evolving, interdependent institutions. Will the Semantic Web Change Ed u c a t i o n ? C l a rk, Parsia & Hendler (2004) 1 h t t p : / / c i t e s e e r. n j . n e c . c o m / h a l a s z 9 4 d e x t e r. h t m l 2 h t t p : / / w w w. z vo n . o r g / t m R F C / R F C 1 4 3 6 / Ou t p u t / 3 h t t p : / / w w w. x a n a d u . c o m . a u . / 4 h t t p : / / w w w. i g d . f h g . d e / a rc h i ve / 1 9 9 5 _ w w w 9 5 / p ro c e e d i n g s / p a p e r s / 1 0 5 / h g w 3 . h t m l Journal of In t e r a c t i ve Media in Education, 2004 (3) Page 2 Will the Semantic Web Change Ed u c a t i o n ? C l a rk, Parsia & Hendler (2004) Because text is, in one sense, a static cultural artifact, dynamic cultural institutions, like the modern university-situated re s e a rch library, we re developed, out of pre existing institutions, of course, in order to nurt u re -that is, to organize, categorize , p re s e rve -texts. Texts can point, in a variety of ways, to other texts, a point often made by various post-structuralist theorists who talk of intertextuality as a fundamental cultural force. (See, for example, the work of Roland Ba rt h e s5.) In some ways intertextuality is the precursor of modern, digital hypertext and hypermedia. And, more to the point in this context, there are various kinds of scholarly apparatus designed to create links between scholarly texts; in the modern era, the footnote and endnote are the primary means. But since these links are conceptual, rather than implementational, the unive r s i t y needs an institution that serves as a nurturing re p o s i t o ry of all such re l e vant texts, such that enacting or activating these conceptual links becomes a matter of physically manipulating -locating, paging through, reading -other texts. Many fields of academic inquiry in the modern re s e a rch university today are still centered aro u n d these practices, which are largely unchanged over the past two or three centuries. In many fields a common scholarly practice is to enter an area of study by finding a text which serves as a guide, and then by following all of its various links to other texts, to journal articles, to conference proceedings, and the like. In order to make that a realistic practice, such that it could underwrite and support other scholarly practices which together form academic, inquiring communities, the u n i versity took on the role of a cultural and scholarly re p o s i t o ry of texts, together with various attendant practices: information space organizational schemes (Dewe y Decimal, Library of Congress, etc.); scholarly re s o u rce sharing schemes (inter-library loan); pre s e rvation of non-scholarly but otherwise formal or official texts (for example, federal government and other public interest arc h i ves). These social practices are constrained by the technologies (printed books, libraries, c a rd catalogs, footnotes, endnotes, indexes) which make them possible and call them f o rth; likewise, these technologies are constrained in that they are used in t h e s e s o c i a l practices and not in others. A parallel sort of relation between social practices, embedded in communities of inquiry, and technologies has been developing for as long as the Web has had a presence in higher education. We should expect, there f o re , that the Web may make possible different modes of scholarly practice and discourse, including different modes of publication, citation, and information organization, because it is based on a technology -distributed, decentralized hypertext -with a d i f f e rent set of affordances than printed text. 5 h t t p : / / we . g o t . n e t / ~ t u t t l e Journal of In t e r a c t i ve Media in Education, 2004 (3) Page 3 Will the Semantic Web Change Ed u c a t i o n ? C l a rk, Parsia & Hendler (2004) 6 h t t p : / / c i t e s e e r. n j . n e c . c o m / Journal of In t e r a c t i ve Media in Education, 2004 (3) Page 4 Indeed, this is exactly what we see happening on the We b. Some of the emerging practices include less costly forms of academic publication, including We b o n l y journals, virtual conferences, purely ad hoc, geographically distributed study and affinity groups, distance education, preprint paper and re s e a rch sharing patterns, personal scholarly publishing, the diminishment of journal and press editors as arbiters of academic standards and taste. (In addition, collaboration on the We b, and the reach of the Internet technology that supports it, has led to a proliferation of other collaboration technologies like Internet Relay Chats and Instant Me s s e n g e r Se rvices, but we do not address their effect in this paper.) Let's consider for a moment a ve ry concrete example. The foot or endnote is a significant element of scholarly discourse. But the Web's hypertext model actually contains no concept which is strictly equivalent to the printed page, at the foot of which one might add a note. One of the discursive differences the move fro m footnotes to hypertext links makes possible is a more indirect scholarly style of e x p ression. In a scholarly text, replete with footnotes, one directly expresses the linkage between the present text and another one. These direct expressions run fro m the concise -a bare footnote, "See also", "Cf." -to the verbose -"As the influential C . P. Sn ow argued in his landmark essay, ..." -but in each case the linkage is only peripherally related to the text itself. The linkage itself cannot be easily associated with an arbitrary sequence of text, as it can in a Web publication. Thus, rather than creating concise or verbose linkage markers, scholarly discourse on the hypertextual Web is able to interleave and interwe a ve such linkages within the main text itself. We can -arbitrarily or elegantly -make any text, within a scholarly h y p e rtext, link to any other Web re s o u rce (or even to named parts, or fragments, of other Web re s o u rces). That difference in technology,


Hypertext: Beyond Te x t
T h e re are many models of hypertext, each of which has various richnesses and a f f o rdances and degrees of expre s s i v i t y.The Web's hypertext model is a re l a t i ve l y i m p overished one, especially as compared with models which include bidire c t i o n a l links, re s o u rce versioning, default genre and document stru c t u res, guided paths t h rough re s o u rces, re s o u rce and re s o u rc e -p a rt annotations, and so on.[The De x t e r Hy p e rtext Re f e rence Mo d e l 1 ; Go p h e r 2 ; Xanadu 3 ; Se rving Information to the We b with Hy p e r -G 4 ] Despite, or some would argue because of, the Web's simple model, it has had a greater impact than any of the more expre s s i ve technologies that p roceeded it.
The primary reason that the Web has been so much more widely accepted is that it was designed to allow two key capabilities: openness and scalability.The first re s u l t e d f rom a conscious design decision that one should be able to link to other people's re s o u rces without any need for permission, and that one could make a re s o u rc e a vailable on one's own server in such a way that others could link to it.The second is achieved by the Web's capability to take advantage of a network effect: If I cre a t e something, and you create something, we can point to each other's re s o u rces, rather than having to duplicate re s o u rces.This is the Web in the World Wide Web --and the network effect is where most of the power comes from --it is often easier to c reate content (with pointers) on the Web than to duplicate that information e l s ew h e re.Thus, the one of the fundamental design goals of the Web was to use a re l a t i vely impoverished hypertext model that was open and scalable, rather than to use or develop a more expre s s i ve hypertext model that was more re s t r i c t i ve .

. Academic Practice
One way to judge the impact of the Web on higher education is by judging the distance between text and hypertext, particularly with re g a rd to academic practice.Historically the various printed page technologies and the unive r s i t y, as well as the re s e a rch library, have been co-evolving, interdependent institutions.

Will the Semantic Web Change Ed u c a t i o n ?
C l a rk, Parsia & Hendler (2004) 1 h t t p : / / c i t e s e e r. n j .n e c .c o m / h a l a s z 9 4 d e x t e r. h t m l 2 h t t p : / / w w w. z vo n .o r g / t m R F C / R F C 1 4 3 6 / Ou t p u t / 3 h t t p : / / w w w. x a n a d u .c o m .a u ./ 4 h t t p : / / w w w. i g d .f h g .d e / a rc h i ve / 1 9 9 5 _ w w w 9 5 / p ro c e e d i n g s / p a p e r s / 1 0 5 / h g w 3 .h t m l Because text is, in one sense, a static cultural artifact, dynamic cultural institutions, like the modern university-situated re s e a rch library, we re developed, out of preexisting institutions, of course, in order to nurt u re --that is, to organize, categorize , p re s e rve --texts.Texts can point, in a variety of ways, to other texts, a point often made by various post-structuralist theorists who talk of intertextuality as a fundamental cultural force.(See, for example, the work of Roland Ba rt h e s5 .)In some ways intertextuality is the precursor of modern, digital hypertext and hypermedia.And, more to the point in this context, there are various kinds of scholarly apparatus designed to create links between scholarly texts; in the modern era, the footnote and endnote are the primary means.
But since these links are conceptual, rather than implementational, the unive r s i t y needs an institution that serves as a nurturing re p o s i t o ry of all such re l e vant texts, such that enacting or activating these conceptual links becomes a matter of physically manipulating --locating, paging through, reading --other texts.Many fields of academic inquiry in the modern re s e a rch university today are still centered aro u n d these practices, which are largely unchanged over the past two or three centuries.In many fields a common scholarly practice is to enter an area of study by finding a text which serves as a guide, and then by following all of its various links to other texts, to journal articles, to conference proceedings, and the like.
In order to make that a realistic practice, such that it could underwrite and support other scholarly practices which together form academic, inquiring communities, the u n i versity took on the role of a cultural and scholarly re p o s i t o ry of texts, together with various attendant practices: information space organizational schemes (Dewe y Decimal, Library of Congress, etc.); scholarly re s o u rce sharing schemes (inter-library loan); pre s e rvation of non-scholarly but otherwise formal or official texts (for example, federal government and other public interest arc h i ves).
These social practices are constrained by the technologies (printed books, libraries, c a rd catalogs, footnotes, endnotes, indexes) which make them possible and call them f o rth; likewise, these technologies are constrained in that they are used in t h e s e s o c i a l practices and not in others.A parallel sort of relation between social practices, embedded in communities of inquiry, and technologies has been developing for as long as the Web has had a presence in higher education.We should expect, there f o re , that the Web may make possible different modes of scholarly practice and discourse, including different modes of publication, citation, and information organization, because it is based on a technology --distributed, decentralized hypertext --with a d i f f e rent set of affordances than printed text.C l a rk, Parsia & Hendler (2004) modest keyword metadata services as well.Thus, without any additional effort on the p a rt of re s e a rchers and scholars --beyond, that is, publishing papers on the Web --C i t e Seer turns the re s e a rch literature of a scientific field into a kind of hypert e x t , t h rough which scholars and other interested parties may wander in the pursuit and s u p p o rt of their own re s e a rch interests and projects.
A second example is the arXiv.orge-Print arc h i ve7 , a site which arc h i ves scholarly a rticles in physics, mathematics, nonlinear sciences, computer science, and quantit a t i ve biology.The focus of arXiv.org is to make papers in these quickly moving fields a vailable as quickly and as easily as possible, in advance of, but not as a substitute f o r, the costly and time-consuming process of peer re v i ew.T h e re is little doubt that peer re v i ew, in some form, is absolutely essential to pro g ress in fields of academic i n q u i ry.But, as it is most often practiced in many fields today, peer re v i ew is essentially unchanged since the post-WWII generation, it can hinder fields undergoing rapid or exploratory advances., and it may be re c o n f i g u red to more ideally fit contemporary realities (See P. Ginsparg, Winners and Losers in the Gl o b a l Re s e a rch Vi l l a g e8 ).By providing an initial clearing house for (primarily) physics and mathematics papers --which are ve ry often submitted simultaneously to both a r X i v.org and to a peer-re v i ewed journal --arXiv.orgsupplements existing academic practice by providing a ubiquitously reachable arc h i ve of re l e vant materials.
For the general audience, the Web has replaced the encyclopedia as the entry point (and more) into arbitrary topics of inquiry.Aside from classic re f e rence materials -e n c yclopedias, dictionaries, and scholarly paper indexes --republished on (and enhanced for) the We b, and even aside from standard scholarly material --art i c l e s , monographs, proceedings --published or republished on the We b, there are massive s of interconnected l i g h t we i g h t c o m m e n t a ry, both individual and collaborative, fre e l y a vailable, often easy to find, and typically trivial to create.Lecture notes, class notes, email exchanges, presentation slides, syllabi and reading lists, study questions and a n s wers --all of these we re once primarily shared only via direct personal contact, with only a small fraction of this marginalia of academic life published in collections and treatises.As the Web becomes a primary medium of academic and pedagogic interaction, all that was once ephemeral, parochial, and largely hidden becomes more permanent and universally ava i l a b l e .

. 2 Pedagogic Practice
Aside from a trickled down effect from the ongoing transformation of academic practice, the Web has directly changed education, most obviously in the way classes a re organized and taught.T h e re are innumerable classes a b o u t the We b, from simple " h ow to browse the Web and write HTML" to complex Web-based information design.Many schools now teach advanced web search techniques, as opposed to physical library search methods, to junior high school students.T h e re are also classes which use the Web to disseminate course material and collect assignments.
In t e re s t i n g l y, classes about the Web are not a subset of classes that at least minimally use the We b.T h e re are classes which significantly incorporate the We b, e.g., where course materials and assignments aren't merely transmitted by the We b, but are enduring, ongoing Web sites, or where significant class discussion occurs in We b based or reflected fora.And, finally, there are classes which are conducted entirely on the Web without the requisite for physical presence.As with many technological re volutions, in the early days of the We b, any class which wanted to make significant use of the Web had to also be a class about the We b, at least to the extent of p roviding minimal sufficient training in browsing and publishing Web pages.As We b literacy spreads, this portion of general-topic Web-using classes has been reduced to dealing with idiosyncratic Web applications used by the class (say, a custom discussion board or Wi k i Wi k i Web) and tips on finding subject-specific good information on the We b.
The transition from academic communities focused on text to academic communities also focused on hypertext has matured and borne real fruit (re f e rence).We suggest that with the next transition, from hypertext to knowledge re p resentation on the Semantic We b, that new social practices and institutions are likely to appear.

. Semantic Web Changes
If the Semantic Web means anything, it means changing the Web's infrastru c t u re such that information exchanges between computers alone become as ubiquitous, c h e a p, and easy as exchanges between humans, mediated by the We b, are alre a d y.
One vital goal, howe ve r, is to make inter-machine exchanges possible without doing permanent damage to the ecology of the Web: inter-machine exchanges are not meant to replace or supplant inter-human ones, merely to supplement them.

Will the Semantic Web Change Ed u c a t i o n ?
C l a rk, Parsia & Hendler ( 2004)

. 1 Beyond Hypertext
So far we ' ve argued that the Web's hypertext model, though expre s s i ve l y i m p overished in comparison to other hypertext models, has been widely successful in and across a great many parts of society, including higher education.The differe n c e s b e t ween text and hypertext have called forth and made possible intere s t i n g d i f f e rences in the way academic communities constitute themselves and enact their scholarly practices.
The success of the Web suggests, howe ve r, that the network effect is more import a n t than the expressivity of the hypertext model.In some sense the fact that millions of people are engaged in a wide diversity of interesting projects and activities using the Web ove rwhelms the fact that the Web's hypertext model is re l a t i vely inexpre s s i ve.It is rather astonishing to explore the rich webs of signification and linkage which have been created on the Web with only the low l y, unidirectional link.The algorithm which powers Google, Page Rank, is based on the unidirectional link, as well as some assumptions, which turn out to be mostly correct, about popularity and re l e va n c e .
That is, we end up getting a lot of power out of a re l a t i vely inexpre s s i ve hypert e x t model, with its untyped, unidirectional link, and the network effect.
Thus, as we begin to see some of the building blocks of the Semantic Web put into place, we anticipate that there will be new practices and institutions that are called f o rth by these new technologies (just as these new technologies are themselves being called forth by a different set of practices and institutions).As we ' ve focused so far on the transition from text to hypertext, we'll now take up the transition fro m h y p e rtext to hypertextual knowledge re p resentation or h y p e rk re p.

. 1 . 1 RDF as a Foundational, Enabling Te c h n o l o g y
T h e re are at least two technologies, in addition to the existing Web infrastucture i t s e l f, which are key to the Semantic Web: RDF9 and OW L 1 0 .RDF, the Re s o u rc e Description Format, which is an XML vo c a b u l a ry, is an assertional know l e d g e re p resentation language, allowing anyone to say anything about anything.How does it accomplish this?The first point to make is that RDF is based on a formally specified semantics, grounded in model theory.How might you go about encoding some bits of knowledge such that Semantic We b agents could interpret them.Let's begin by rewriting our simple sentence in a longer but slightly more literal form: "There is a book that is titled 'The Two Cu l t u re s . . .' and its author is 'C.P. Sn ow'".Mo re awkward, more wooden, and more verbose, but this version of our sentence is semantically equivalent.
How might we encode this strange set of sentences in RDF?That is, how might we encode it as a set of three-tuples of the form (subject, predicate, object)?First we will g i ve the encoding, then we will explain it: What have we done here?First, we ' ve said that the web re s o u rc e , h t t p : / / w w w. c p s n ow.o r g / t w o -c u l t u res is (or, more accurately, re p resents a thing which is) a book.The term form "xxx:yyy" is a kind of abbreviation, known as an XML qualified name or "qname".It means that we ' re using a term from an existing vo c a b u l a ry or set of terms, rather than making up our own.The RDF specifications f rom the W3 Consortium, specify that "rdf:type" is a term which means, ro u g h l y, "is-a".You can read that first triple as, ro u g h l y, "the web re s o u rc e , h t t p : / / w w w. c p s n ow.o r g / t w o -c u l t u res, is of the type cpss:book".Perhaps the CP Sn ow Society doesn't know or approve of existing sets of terms which define "book", so it's defined its own, using the prefix "cpss".
The second triple can be read as saying that "there is a web re s o u rc e , h t t p : / / w w w. c p s n ow.o r g / c p s n ow, which is or re p resents the entity which is the author of another web re s o u rce, http://www.c p n s ow.o r g / t w o -c u l t u res".We know this second web re s o u rce, the one in the object position in the second triple, is a book, because that was the assertion made in the first triple.Putting these together, we ' ve now said that there is a book, identified by such-and-such a web re s o u rce, which was authore d by some entity, identified in turn by such-and-such a web re s o u rce.L a s t l y, the two final triples says that there is a web re s o u rce, which we now know to be a book, that has the title "The Two Cu l t u res..." and a specific date.Rather than making up our own terminology for date and title, we use the we l l -k n own D u b l i n C o re meta-data standard using its common qname prefix "dc:" to denote it.
That's not so difficult.We ' ve expressed a helpful bit of knowledge, and we ' ve done so in a way that can be easily turned into a format that Semantic Web agents can understand --a format backed by a rigorous, formal semantics.Now, suppose we want to say a bit more?Suppose we want to say a bit more about C.P. Sn ow, the natural person, himself?We can start to see a bit of the promised power of the Semantic Web by taking this question a little furt h e r.
Even though all of the web re s o u rces discussed so far are mythical, there is a good chance that you have been assuming a particular thing about them, namely, that if t h e re we re such re s o u rces on the We b, what you would find when you used your we b b rowser to visit them would be some HTML.That's a perfectly re a s o n a b l e assumption, given the past 10 or so years of history and experience with the We b.You can read the first triple as saying, ro u g h l y, that "there is a web re s o u rc e , h t t p : / / w w w. c p s n ow.o r g / c p s n ow, which re p resents a natural person".In this case we ' re using the term foaf:Person, which means we ' re using the term "Person" drawn f rom a vo c a b u l a ry called "Friend of a Friend", a common way to re p re s e n t information about natural persons on the Semantic We b.Next, "there is a we b re s o u rce, which re p resents a natural person, that is named 'C.P. Sn ow'"; third, "there is a web re s o u rce, which re p resents a natural person of the male gender".
Note the network effect is once again present!The CP Sn ow society let the Du b l i n C o re folks define facts about publication metadata and let the Friend of a Fr i e n d vo c a b u l a ry define facts about people.DC and FOA F, in turn, may link to other documents that re p resent other types of information and so on and so forth.In s t e a d of eve ry document making up its own re p resentaion, they are linked into a Web of semantic re p re s e n t a t i o n .
One may quickly see, or so we think, that if a great many affinity groups within higher education --study groups, learned societies, scholarly conferences and colloquiums, departments, colleges, seminars, groups of students, groups of students and a faculty member, and so on --develop in the next five years even one hundre d t h as many RDF re s o u rces as they have created HTML re s o u rces in the past five ye a r s , then the Semantic Web will become a thing ve ry rich in knowledge, that is, in k n owledge discoverable and consumable by machines and agents.

. 1 . Adding a Web Ontology Language (OW L )
OWL is a newly developed ontology language for the We b.An ontology language is a means by which one can formally describe a knowledge domain, with the goal of

Will the Semantic Web Change Ed u c a t i o n ?
C l a rk, Parsia & Hendler (2004) enabling computers to provide various kinds of reasoning services about that domain, and about the knowledge described by an ontology for that domain.In our curre n t , technical usage, an ontology is a formal specification of a knowledge domain: what individuals and classes of individuals there are in that domain, the re l a t i o n s h i p s which obtain between these individuals and classes, their proper and apparent part s , and so on.Thus, using OWL one can formally specify a knowledge domain, describing its most salient features and constituents, and then use that formal specification to make assertions about what there is in that domain.You can feed all of that to a computer which will reason about the domain and its knowledge for you.And, h e re's the most tantalizing bit, you can do all of this on, in, and with the We b, in both interesting and powe rful ways.
Two brief points: First, we all spend some amount of our brain power --almost e n t i rely without consciously knowing that this is what we are doing --dealing with informal, implicit ontologies.In order to act meaningfully at all within part i c u l a r social contexts, we need to have understood something roughly like an ontology of that context.In any situation or context there will be features which we attend to, because they just are the salient features of that context, and an even larger number of things about the situation which we do not attend to, which we cannot even call f e a t u res, because they are the background noise against which salience emerges.Second, unlike humans, computers can only provide reasoning services over a k n owledge domain because the domain and the knowledge have been formally and r i g o rously specified in advance and because some human has implemented va r i o u s reasoning algorithms in a way which that computer can apply.
From these two points we may be able to conclude that ord i n a ry people, with the right support and motivation, can learn to use the formal tools of computerize d ontology languages, like OWL, to re p resent the things which they already know in a way which computers can then reason about, as a supplement and aid to human i n t e rests.It's worth noting that the alternative, expecting the computer to understand and reason with human concepts and language, is far beyond the curre n t s t a t e -o f -t h e -a rt, if achievable at all.
So far nothing we have said about ontology languages and reasoning systems is specific to OWL as an ontology language for the We b.Howe ve r, OWL has been specifically crafted out of its Webbish fore runners, particularly SHOE 1 1 a n d D A M L + O I L 1 2 , to take advantage of some of the interesting things about the We b.OWL is intended to be an ontology language that has the following features: it should operate at the scale of the Web; it should be distributed across many systems, a l l owing people to share ontologies and parts of ontologies; it should be compatible with the Web's ways of achieving accessibility and internationalization; and it should be, re l a t i ve to most prior knowledge re p resentation systems, easy to get started with, n o n -p ro p r i e t a ry, and open.In short, OWL was based on the same principles we mentioned about the Web itself much earlier in this discourse --openness and scalability to allow a network effect.
Insofar as OWL accomplishes or will accomplish these goals, it will do so by virt u e of the fact that it was designed by a collection of Know l e d g e R re p resenation and We b e x p e rts, with the explicit goal of making a formal knowledge re p resentation (KR) language work on the world's first globally distributed hypermedia system.This is a re l a t i vely new thing to aim at in the history of KR systems.In some ways, the OW L Wo rking Group (WG) is among the most ambitious of the W3C's many WGs.It is often said of W3C WGs that they are not meant to do new work, that is, to do new re s e a rch into some field; rather, they are meant to standard i ze and specify things which are already known in such a way that makes open computing possible and p ro p r i e t a ry vendor lock-in improbable.In the case of the OWL WG, howe ve r, this general rule was broken.While OWL has precursors, the most important of which is DAML+OIL, it took a non-trivial amount of real, new technical work to make OW L into a practical ontology language for the We b.
Despite our enthusiasm for OWL, we have to temper it with a dose of realism.OW L can be and probably is eve rything good which people have said about it; if so, that in and of itself will not mean that the Semantic Web visions will be widely achieve d .Whether or not the Semantic Web ever happens, in as robust and important a sense as the original Web happened, depends on a complex set of factors and their interactions, only some of which are under anyone's direct control.
Having OWL means a few things are no longer true.First, it is no longer true that the Semantic Web can be dismissively written off as a bit of magical, wishful thinking on the part of some Utopian-leaning technologists.OWL provides a real foundation, rooted in the rich re s e a rch and engineering tradition of KR and DL, for the Se m a n t i c We b.Second, it is no longer true that RDF and RDF Schemas are the obv i o u s choices for a certain class of Web applications.OWL will soon be considered in some cases a better choice than RDF alone; it is more expre s s i ve and, in the OWL Fu l l variant, upw a rdly compatible with RDF.
To see how OWL can be used, we return to our earlier example.ow and expect an OWL system to correctly infer which work s we ' ve already described fall into which class.The C.P. Sn ow society can build upon these concepts to express the distinction between works and articles solely written by Sn ow and collaborative works (e.g., by defining Wo rk s By On l y Sn ow as a subclass of Wo rk s By C P Sn ow where there is only one author, and CollaborationsWi t h Sn ow as the subclass of Wo rk s By C P Sn ow where there is at least one author who isn't snow).While helpful for organizing the C.P. Sn ow society's Web site, such an ontology only becomes interesting, and only become a true We b o n t o l o g y, when it is published on the Web for all and sundry to examine, use, extend, or dispute, along with the facts ( e x p ressed in RDF) the ontology is meant to organize.Anyone, anywhere on the We b could then take the facts and impose an alternative or rival organization upon them, or take both the facts and the ontology and refine the ontology to greater detail.In this way, the Semantic Web enables non-coordiated (and even non-cooperative ) collaboration about a domain of discourse, one in which the c o n c e p t u a l w o rk is aided and abetted by programs.Not only will our Web Agents find and aggre g a t e information from the Web (and without fragile and error prone "scraping" of HTML pages), but they will be able to give some initial guidance about whether cert a i n a g g regations make sense.

. Everyone is a Hyperkrep Hacker?
Traditional knowledge re p resentation oriented development, say, for expert systems, has re q u i red a strong division of labor between, at least, the domain expert and the k n owledge engineer.Even when these two roles are performed by the same person, k n owledge engineering re q u i res a skill set that is not common, and is generally c o n s i d e red difficult to master.Even if the ontology is developed and deploye d , adding new information or interpreting claims made by the system can be difficult.
In the Semantic Web vision, there is the expectation that hordes of developers, we b

Will the Semantic Web Change Ed u c a t i o n ?
C l a rk, Parsia & Hendler (2004) masters, page authors, and even casual users will be creating and consuming Se m a n t i c Web data.Eve ryone will be hyperk rep hacker, able to casually create a mix of hypermedia and knowledge re p resentation that fits in to the global hyperk rep system.
Why do we think that it's even possible, much less likely, that eve ryone can become a hyperk rep hacker?T h e re was a time, not so long ago, when things like hypert e x t , m a rkup languages, and relational database systems we re considered too complex for most programmers or technically-sophisticated people.But these technologies, and the concepts they express, have become the building block of the Web as we know it t o d a y.Today more people than anyone eve ry imagined build complex web sites and applications using XML, SQL, and a lightweight, high-level programming language.
Why did so many people learn to use such complex technologies?Because they we re highly motivated by and committed to the success of the We b.T h e re's no reason to b e l i e ve that this same kind of thing won't happen for the Semantic We b.Logic p rogramming, knowledge re p resentation, and ontology modeling sound like ve ry intimidating, complex tools and techniques.And in some ways they are; but no more so, or so we believe, than the technologies powering the first generation of the We b.
For classes, the sitution will be must the same as for the We b.Early adoptors will be faced with the tasks of teaching the (Semantic) Web as well as teaching their subject m a t t e r.As the Semantic Web becomes more pre valent, as people start getting RDF classes in high school, as more people explore putting up their own Semantic We b pages, it will become ve ry difficult n o t to use the Semantic Web in teaching, learning, re s e a rch, and related activities and practices.

. 3 Semantics, Ontologies, and Education
So what impact may all this RDF and OWL have on the educational enterprise?Ju s t as it was impossible to predict which features of the Web would have what impacts on institutions of higher learning, it is difficult to guess where the impacts of the Semantic Web will be most deeply felt in academia.Howe ve r, one area where it seems fair to guess about the impact is in the area of the continued evolution of electro n i c publishing, continuing the trends we discussed earlier.
Using ontologies, in the next few years, we expect that tools for publishing will automatically help users to include machine-readable markup in the papers they p roduce.W h e reas current tools using XML (Extensible Ma rkup Language) can allow a user to assert that some part of a document is about an 'experiment', the new languages will let the author express that the experiment uses certain chemicals and reagents; that the system used invo l ved some particular organic matter; that the experiment produced gels with certain DNA information on them (and that the images of these gels are located in particular places on the web); and other domainspecific concepts expressed based on an OWL ontology (early versions of such tools a re already becoming available.) Papers that include this new markup language will be found by new and better searc h engines, and users will thus be able to issue significantly more precise queries.Mo re i m p o rt a n t l y, experimental results will themselves be published on the we b, outside of the context of a re s e a rch paper.So a scientist could design and run an experiment, and create an emerging web page containing the information that he or she wants to s h a re with trusted colleagues.Finding out about experiments and studies in pro g re s s will be easy, and work will be able to be modified as a result of interaction with peers, with less need to wait for formal publication.Just as preprints challenge established journal publishing approaches, these new 'papers in pro g ress' will change the culture of publishing (and of the pursuit of science).
Ad d i t i o n a l l y, the added expressivity of the Semantic We b, coupled with search and q u e ry tools already under development, will allow changes in non-scientific fields as well.For example a number of historians could each annotate the same document to e x p ress differences of opinion about its comment, creating communities of d e c o n s t ruction.Filtering mechanisms could provide capabilities for seeing annotations by some particular colleague, by all colleagues, by colleagues from a specific institution, etc. Non-historians could see these annotations and explore the m a rked up documents in other ways --perhaps exploring them semiotically or eve n using pseudo-sciences like handwriting analysis or horoscopic analysis of the dates of publication (re m e m b e r, it's the We b, eve ryone can play!)Thus, it is not unreasonable to assume that in the long run, the Semantic Web will facilitate the development of methods for helping users to understand and to re c re a t e in new contexs the content and knowledge produced by those in other disciplines.
On the Semantic We b, one will be able to produce machine-readable content that will provide, say, automated translation between the output of a data collection study (say the cancer risk assessment tables published by the EPA) and the input of a datamining package developed for some scientific pursuit (perhaps genomic databases).Mechanisms used in one field or discipline become available and linked, in real time, for others, creating a network effect in academic knowledge itself.The ve ry notion of a journal of medicine separate from a journal of bioinformatics, separate from the Indeed, this is exactly what we see happening on the We b.Some of the emerging practices include less costly forms of academic publication, including We b -o n l y journals, virtual conferences, purely ad hoc, geographically distributed study and affinity groups, distance education, preprint paper and re s e a rch sharing patterns, personal scholarly publishing, the diminishment of journal and press editors as arbiters of academic standards and taste.(In addition, collaboration on the We b, and the reach of the Internet technology that supports it, has led to a proliferation of other collaboration technologies like Internet Relay Chats and Instant Me s s e n g e r Se rvices, but we do not address their effect in this paper.) Journal ofIn t e r a c t i ve Media inEducation, 2004 (3)Page 4 The main idea behind RDF is that knowledge can be re p resented as a graph of d i rected, labeled arcs; one makes assertions about a thing by means of associating subjects and objects by way of predicates.Put the other way around, RDF graphs are full of things called "triples", which are three-tuples, or assertions, containing subject, predicate, and object terms.What makes RDF particularly useful in the context of the Web and the Semantic Web is that the value of these terms --subject, p redicate, object --may each be a URI."URI" stands for Un i versal Re s o u rc e Identifier; it is the term most commonly used for what was formerly called a URL or Un i versal Re s o u rce Locator.
Let's take a concrete, if contrived and simplistic example.You are a philosopher of science and a member of the (mythical, as far as we know) C.P. Sn ow So c i e t y.T h e society maintains a presence on the Web at http://www.c p s n ow.org/, which includes a few notable resources: a page about C.P. Snow himself, http://www.cpsnow.org/cpsnow/,and a page about his famous little book, The Two C u l t u res and the Scientific Re vo l u t i o n, h t t p : / / w w w. c p s n ow.o r g / t w o -c u l t u res.Imagine, furt h e r, that you would like to re p resent some knowledge; for example, "C.P. Sn ow wrote a book called The Tw o Cu l t u res and the Scientific Re vo l u t i o n" .
Suppose the C.P. Sn ow Society wants to organize its bibliographic information already encoded in R D F. To take a simple example, they would like to distinguish between works by Sn ow and works a b o u t him.In OWL, we can express these concepts using class e x p ressions, in part i c u l a r, re s t r i c t i o n s on the various pro p e rties a work has.Fo r example, the class of work by C.P. Sn ow is just the set of work which have h t t p : / / w w w. c p s n ow.o r g / c p s n ow (the person designated by this URI) as their d c : a u t h o r, while the class of works by C.P. Sn ow is just the set of works which have h t t p : / / w w w. c p s n ow.o r g / c p s n ow as (one of ) their dc:subject(s).We can easily expre s s these definitions in OWL, give names to these concepts (e.