Common Web Language

W3C Incubator Group Report 31 March 2008

This version:

http://www.w3.org/2005/Incubator/cwl/XGR-cwl-20080331/

Latest version:

http://www.w3.org/2005/Incubator/cwl/XGR-cwl/

Previous version:

This is the first public report.

Editor:

Hiroshi Uchida

Authors:

Hiroshi Uchida, Institute of Semantic Computing

Toshio Yokoi, Institute of Semantic Computing

Meiying Zhu, Institute of Semantic Computing

Nobuo Saito, Keio University

Vahan Avetisyan, UNL Armenian Language Centery

Contributors:

Hiroshi Yasuhara, Institute of Semantic Computing

Also see Acknowledgements

Copyright © 2008 W3C^® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.

Abstract

This is a report of the W3C Common Web Language Incubator Group (CWL-XG) as specified in the Deliverrables of its charter.

In this report we define the Common Web Language (CWL) Specifications and introduce various forms of representation of CWL and its platform to work with CWL.

Specifically the report:

• defines, the CWL Archtecture,
• presents the CWL specification,
• discusses the merit to have various forms of representation,
• describes, how to use CWL using CWL platform
• proposes, the use for CWL for multilingualism of web.

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of Final Incubator Group Reports is available. See also the W3C technical reports index at http://www.w3.org/TR/.

This document was developed by the W3C Common Web Language Incubator Group, part of the W3C Incubator Activity.

Publication of this document by W3C as part of the W3C Incubator Activity indicates no endorsement of its content by W3C, nor that W3C has, is, or will be allocating any resources to the issues addressed by it. Participation in Incubator Groups and publication of Incubator Group Reports at the W3C site are benefits of W3C Membership.

Incubator Groups have as a goal to produce work that can be implemented on a Royalty Free basis, as defined in the W3C Patent Policy. Participants in this Incubator Group have made no statements about whether they will offer licenses according to the licensing requirements of the W3C Patent Policy for portions of this Incubator Group Report that are subsequently incorporated in a W3C Recommendation.

1. Introduction

The CWL, a common web language for humans and computers, must solve the following two big problems exist in the present web world. One is the language barriers in the web, and another is lacking of machine understandability for the contents in the web.

Language barrier:

Currently almost all web pages are written in English. It is convenient for English speaking people but it is not for non-English speaking people, and those people are the majority in the world. Those people cannot get information easily, because it is not written in their mother tongue. Recently machine translation facilities are equipped in the web, but it is not the solutions. Machine translation has a problem of quality and coverage of languages.

Machine Understandability:

HTML tags give information on structure of web documents, but they do not give semantic information on each words nor sentences in documents. It means HTM tags information is insufficient to intellectually utilize contents of web pages. The RDF and OWL have a framework to give semantic information but they do not have standard vocabulary to describe web contents.

1.1 Objective of CWL

Objectives of CWL is for exchanging information through the web and also for enabling computers to process information semantically. The CWL allows people to describe contents and meta-data of web pages written in natural languages and also allows realizing a language barrier free world in the web and it will also enable computers to extract semantic information and knowledge from web pages accurately.

1.2 Requirement for CWL

The requirements for CWL to achieve the above objectives are the followings.

1. To be independent from any natural languages and shall enable users to develop conversion systems between CWL and each natural language easily.
2. Different from natural languages, CWL is a unambiguous formal language playing the same role of natural languages for humans.
3. Concepts included in any natural language can be the vocaburary of CWL.
4. Surface structure and semantic structure of original document must be expressed in CWL.

2. CWL Architecture

The CWL is a graph language of semantic hyper directed graph, a node represents a concept, an arc represents a relation between nodes and a node can be annotated by attributes. This CWL can be expressed in three languages UNL, CDL and RDF/OWL. The same information in CWL can be described in each language but in different manner. The CWL.unl is a language based on UNL. The CWL.cdl is a language based on the CDL. The CWL.rdf is a language based on RDF/OWL.

Three different types of representations of CWL allow different way of treatment of the same information described. The CWL.unl is for multilingualism, The CWL.cdl has compatibility with semantic computing systems for semantic computing, The CWL.rdf is for working with various data navigation and aggregation systems (like SPARQL).

Compatibility among expressions in UNL (CWL.unl), CDL (CWL.cdl), and RDF is guaranteed. Followings are the expression of each representation for the sentence `I purchased a computer yesterday.'.

CWL.unl expression

{unl} //Table Form of UNL expression
agt(purchase(icl>buy(agt>person,obj>thing)).@entry.@past), I)
obj(purchase(icl>buy(agt>person,obj>thing)).@entry.@past),computer(icl>machine))
tim(purchase(icl>buy(agt>person,obj>thing)).@entry.@pst), yesterday(icl>day))
{/unl}

CWL.cdl expression

{#S Situation;
  {#A Event tmp='past';
    {#A1 purchase (icl>buy(agt>person,obj>thing) ;}
    {#A2 I ral='def';}
    {#A3 computer(icl>machine) ral='def';}
    {#A4 yesterday(icl>day) ral='def';}
    [#A1 cdd.nl#agt #A2]
    [#A1 cdd.nl#obj #A3]
    [#A1 cdd.nl#tim #A4]
  }
}

CWL.rdf expression

RDF// N-Triples representation: Subject Property Object"."
#S rdf:type Situation.
#A rdf:type Event.
#S hasComplexEntity #A.
#A hasElementalEntity #A1.
#A hasElementalEntity #A2.
#A hasElementalEntity #A3.
#A hasElementalEntity #A4.
#A1 rdf:type purchase(icl>buy(agt>person,obj>thing).
#A2 I rdf:type I.
#A2 I ral 'def'.
#A3 rdf:type computer(icl>machine).
#A3 ral 'def'.
#A4 rdf:type yesterday(icl>day).
#A4 ral 'def'.
#A1 agt #A2.
#A1 obj #A3.
#A1 tim #A4.
#A tmp 'past'.

2.1 CWL

The CWL is designed to be used to describe meta-data and contents of web pages for breaking language barriers and enable computers to process web information semantically. The CWL is a graph language of extended semantic hyper directed graph, a node represents a concept, an arc represents a relation between nodes and a node can be annotated by attributes. Every node including nodes in hyper nodes can have relation with any other nodes.

A concept can be expressed in any kind of a morpheme, a word, a phrase, a clause or a sentence of any language and a Universal Word developed by the UNDL Foundation. A concept (character strings) express the meaning/concept that a a morpheme, a word, a phrase, a clause or a sentence can express in each language.

The meaning of a concept in CWL depend on the context. It means the meaning of a concept in CWL is restricted by relations with other concepts linked with arcs going in and out.

The following is a CWL.unl graph representation for the sentence `Long ago, in the city of Babylon, people begun to build a huge tower, which seemed about to reach the heavens.'

begin.entry.past-- tim->long ago
    --plc->city.def
    --agt->people.def
    --obj->build.past--obj-> tower<- aoj--huge<- seem.past
                     --obj->reach.bigin.soon--obj->tower
                     --gol->heaven.def.pl

Compatibility among expressions in UNL (CWL.unl), CDL (CWL.cdl), and RDF is guaranteed. Followings are the expression of each representation for the sentence `I purchased a computer yesterday.'.

{cwl.unl}
tim(begin.@entry.@past,long ago)
mod(city.@def,Babylon)
plc(begin.@entry.@past,city.@def)
agt(begin.@entry.@past,people.@def)
obj(begin.@entry.@past,build.@past)
agt(build,people.@def)
obj(build,tower)
aoj(huge,tower)
aoj(seem.@past,tower)
obj(seem.@past,reach.@begin.@soon)
obj(reach.@begin.@soon,tower)
gol(reach.@begin.@soon,heaven.@def.@pl)
{/cwl.unl}

Relations constitute syntax of the CWL. They expresses objectivity together with UWs by describing how concepts(UW) constitutes a sentence related each other. We adopt the relation set of the UNL relation set for the basis of the relation set of CWL. Psudo relations will be added as the need arises.

There are 41 relations, such as "agt", "aoj", "bas", "ben", "cag", "cao", "cnt", "cob", "con", "coo", "dur", "equ", "fmt", "frm", "gol", "icl", "ins", "int", "iof", "man", "met", "mod", "nam", "nxt", "obj", "or", "per", "plc", "plf", "plt", "pof", "pos", "ptn", "pur", "qua", "ref", "rsn", "scn", "seq", "shd", "src", "tim", "tmf", "tmt", "to", and "via".

Attributes describe mainly subjectivity. We also adopt the attribute set of the UNL attribute set as a basis of the attribute set of the CWL. Attributes will be added as the need arises. Attributes are categorized into following 7 groups.at this moment.

Times with respect to the writer

@past, @present, @future

Writer's view on aspects of event

@begin, @complete, @continue, @custom, @end, @experience, @progress, @repeat, @state

Writer's view of emphasis, focus and topic

@contrast, @emphasis, @entry, @qfocus, @theme, @title, @topic

Writer's attitudes

@affirmative, @confirmation, @exclamation, @humility, @imperative, @interrogative, @invitation, @polite, @request, @respect, @vocative

Writer's feelings and judgments

@ability, @get-benefit, @give-benefit, @conclusion, @consequence, @sufficient, @consent, @dissent, @grant, @grant-not, @although, @discontented, @expectation, @wish, @insistence, @intention, @want, @will, @need, @obligation, @obligation-not, @should, @unavoidable, @certain, @inevitable, @may, @possible, @probable, @rare, @unreal, @admire, @blame, @contempt, @regret, @surprised, @troublesome

Writer's view of reference

@generic, @def, @indef, @not, @ordinal

Describing logical characters and properties of concepts

@transitive, @symmetric, @identifiable, @disjointed

Modifying attribute on aspect

@just, @soon, @yet, @not

Attribute for Convention

@passive, @pl, @angle_bracket, @brace, @double_parenthesis,@double_quote, @parenthesis, @single_quote, @square_bracket

2.1.1 Vocabulary of CWL

A concept can be expressed in any kind of a morpheme, a word, a phrase, a clause or a sentence of any language and a Universal Word developed by the UNDL Foundation. A concept (character strings) express the meaning/concept that a morpheme, a word, a phrase, a clause or a sentence can express in each language.

The CWL vocaburary is defined as the CWL ontology. Every concept must be defined in the CWL ontroly. The CWL ontology gives the linguistic knowledge of the CWL. The following hierarchy of concepts is a part of the top ontology.

concept
    nominal copncept
        thing
            abstract thing
                attribute
                    quality
                    feature
                event
                    action
                        mental action
                        physical action
                        process
                    phenomenon
                        mental phenomenon
                        physical phenomenon
                        change
                        process
                information
                    statement
                    description
                quantity
                rule
                state*
                    condition
                    mental state
                    physical state
                    situation
                way
                    arrangement
                    behavior
                    manner
                    method
            attributive thing
                group
                    group(icl>volitional thing)
                    set
            concrete thing
                living thing
                    human
                    animal
                    plant
                natural world
                substance
                ...
            functional thing
                facilities
                symbol
                tool
                ...
            volitional thing
                animal
                group
                human
                ...
            place
                area
                relative place
                ...
            time
                period
                ...
    predicative concept
        do
            act
            express
                state
            get
                obtain
            give
                provide
            make
                produce
            take
            change
            move
            put
            mentally do
            physically do
            do(agt>thing)
            do(agt>thing,obj>thing)
            ...
            treat
            deal
            perform
        occur
            become
            happen
                change
                move
                mentally happen
                physically happen
                ...
            occur(obj>thing)
            occur(gol>thing,obj>thing)
            ...
        be
            be(aoj>thing,obj>thing)
            be(aoj>thing)
            ...
    attributive concept
        (qua<thing)    :quantifier
        (mod<thing)    :modifier
        ...
    adverbial concept
        (qua>quantifier)
        (man<predicative concept)
            how

The CWL ontology also defineds every possible relations between concepts.

2.1.2 Relations

There are many factors to be considered in choosing an inventory of relations between concepts. Different factors taken into account in choosing the relations lead to different sets of the relations. We aopt the relation set of the UNL. The UNL relations are selected basically according to the following principles:

Principles of Relation

PRINCIPLE 1 : NECESSARY CONDITION

When a concept has relations between more than one other concepts, each relation label should be set so as to be able to identify each relation on the premise that there is enough knowledge about the concept of each concept expressed.

PRINCIPLE 2 : SUFFICIENT CONDITION

When there are relations between concepts, each relation label should be set so as to be able to understand the role of each concept only by referring to the relation label.

Relation
    predicative relation
        agt(agent)
        aoj(thing with attribute)
          cag(co-agent)
          cao(co-thing with attribute)
          ptn(partner)
          ben(beneficiary)
          cob(affected co-thing)
          obj(affected thing)
          opl(affected place)
          ins(instrument)
          met(method or means)
          man(manner)
          plc(place)
          plf(initial place)
          plt(final place)
          scn(scene)
          gol(goal, final state)
          src(source, initial state)
          via(intermediate place or state)
          dur(duration)
          tim(time)
          tmf(initial time)
          tmt(final time)
    inter-concept relation
          and(conjunction)
          or(disjunction, alternative)
          fmt(range/from-to)
          frm(origin)
          to(destination)
          equ(equivalent)
          icl(included/a kind of)
          iof(an instance of)
    inter-event relation
        con(condition)
          coo(co-occurrence)
          pur(purpose or objective)
          rsn(reason)
          seq(sequence)
    qualification relation
          bas(basis for expressing a standard)
          cnt(content, namely)
          man(manner)
          mod(modification)
          nam(name)
          per(proportion, rate or distribution)
          pof(part-of)
          pos(possessor)
          qua(quantity)

Definitions of Relations

The following are the relations defined according to the above principles. A relation label is represented as strings of 3 characters or less

(1) agt (agent)

Agt defines a thing (an agent) in focus that initiates an action. It can be a relation between:

do--agt->thing
action--agt->thing

An agent initiate an action indicated by "do" or "action" and is thought of as having a direct role in making the action happen.

Examples and readings

(2) and (conjunction)

And defines a partner to have conjunctive relation. It can be a relation between:

and(concept, concept)

A conjunction is defined as the relation between a concept, and another concept.

Examples and readings

(3) aoj (thing with attribute)

Aoj defines a thing that is in a state or has an attribute. It can be a relation between:

be--aoj->thing
thing--aoj->thing

Examples and readings

(4) bas (standard (basis) of comparison)

Bas defines a thing used as the basis (standard) of comparison. It can be a relation between:

be--bas->thing
do--bas-> thing
how--bas->thing

Examples and readings

(5)ben (beneficiary)

Ben defines an indirectly related beneficiary or victim of an event or state. It can be a relation between:

predicative concept--ben->thing

Examples and readings

(6) cag (co-agent)

Cag defines a thing not in focus that initiates an implicit event that is done in parallel. It can be a relation between:

do--cag->thing

Examples and readings

(7) cao (co-thing with attribute)

Cao defines a thing not in focus that is in a parallel state. It can be a relation between:

be--cao->thing
thing--cao->thing

Examples and readings

(8) cnt (content)

Cnt defines or show the content of a concept. It can be a relation between:

concept--cnt->concept

Examples and readings

(9) cob (affected co-thing)

Cob defines a thing that is directly affected by an implicit event done in parallel or an implicit state in parallel.

predicative concept--cob->thing

Examples and readings

(10) con (condition)

Con defines a non-focused event or state that conditions a focused event or state.

predicative concept--con->concept

Examples and readings

(11) coo (co-occurrence)

Coo defines a co-occurrent event or state for a focused event or state.

predicative concept--coo->predicative concept

Examples and readings

(12) dur (duration)

Dur defines a period of time during which an event occurs or a state exists.

predicative concept--dur->predicative concept
predicative concept--dur->event
predicative concept--dur->period
predicative concept--dur->state

Examples and readings

(13) equ (equivalent)

Equ defines an equivalent concept.

concept--equ->concept

Examples and readings

(14) fmt (range: from-to)

Fmt defines a range between two things.

thing--fmt->thing

Examples and readings

(15) frm (origin)

Frm defines an initial state of a thing or a thing initially associated with the focused thing.

thing--frm->thing
thing->frm->be

Examples and readings

(16) gol (goal: final state)

Gol defines a final state of object or a thing finally associated with the object of an event.

be--gol->thing
do--gol->thing
do--gol->be
occur--gol->thing
occur--gol->be

Examples and readings

(17) icl (included/a kind of)

Icl defines an upper concept or a more general concept.

concept--icl->concept

Examples and readings

(18) ins (instrument)

Ins defines an instrument to carry out an event.

do--ins->concrete thing

Examples and readings

(19) int(intersection)

Int defines an intersection between concepts. a partner to take an intersection

concept--int->concept

(20) iof (an instance of)

Iof defines a class concept that an instance belongs to.

concept--iof->concept

Examples and readings

(21) man (manner)

Man defines a way to carry out an event or the characteristics of a state.

predicative concept--man->how

Examples and readings

(22) met (method or means)

Met defines a means to carry out an event.

do--met->abstract thing
do--met->do

Examples and readings

(23) mod (modification)

Mod defines a thing that restricts a focused thing.

thing--mod->thing
thing--mod->attributive concept

Examples and readings

(24) nam (name)

Nam defines a name of a thing.

thing--nam->thing

Examples and readings

(25) obj (affected thing)

Obj defines a thing in focus that is directly affected by an event or state.

predicative concept--obj->thing

Examples and readings

(26) opl (object place)

Opl defines a place in focus affected by an event.

do--opl->thing
occur--opl->thing

Examples and readings

(27) or (disjunction)

Or defines a disjunctive relation between two concepts.

concept--or->concept

Examples and readings

(28) per (proportion, rate or distribution)

Per defines a basis or unit of proportion, rate or distribution.

thing--per->thing

Examples and readings

(29) plc (place)

Plc defines a place where an event occurs, or a state that is true, or a thing that exists.

predicative concept--plc->place
thing--plc->place

Examples and readings

(30) plf (initial place)

Plf defines a place where an event begins or a state that becomes true.

predicative concept--plf->thing

Examples and readings

(31)plt (final place)

Plt defines a place where an event ends or a state that becomes false.

predicative concept--plt->thing

Examples and readings

(32) pof (part-of)

Pof defines a concept of which a focused thing is a part.

thing--pof->thing

Examples and readings

(33) pos (possessor)

Pos defines the possessor of a thing.

thing--pos->volitional thing

Examples and readings

(34) ptn (partner)

Ptn defines an indispensable non-focused initiator of an action

do--ptn->thing

Examples and readings

(35) pur (purpose or objective)

Pur defines the purpose or objective of an agent of an event or a purpose of a thing that exists.

do--pur->do
do--pur->thing
thing--pur->concept

Examples and readings

(36) qua (quantity)

Qua defines the quantity of a thing or unit.

thing--qua->quantity

Examples and readings

(37) rsn (reason)

Rsn defines a reason why an event or a state happens.

predicative concept--rsn->predicative concept
predicative concept--rsn->thing

Examples and readings

(38) scn (scene)

Scn defines a scene where an event occurs, or state is true, or a thing exists.

predicative concept--scn->thing
thing--scn->thing

Examples and readings

(39) seq (sequence)

Seq defines a prior event or state of a focused event or state.

predicative concept--seq->predicative concept

Examples and readings

(40) src (source: initial state)

Src defines the initial state of an object or thing initially associated with the object of an event.

do--src->thing
do--src->be
occur--src->thing
occur--src->be

Examples and readings

(41) tim (time)

Tim defines the time an event occurs or a state is true.

predicative concept--tim->time
thing--tim->time

Examples and readings

(42) tmf (initial time)

Tmf defines the time an event starts or a state becomes true.

predicative concept--tmf->time
thing--tmf->time

Examples and readings

(43)tmt (final time)

Tmt defines a time an event ends or a state becomes false.

predicative concept--tmt->time
thing--tmt->time

Examples and readings

(44) to (destination)

To defines a final state of a thing or a final thing (destination) associated with the focused thing.

thing--to->thing

Examples and readings

(45) via (intermediate place or state)

Via defines an intermediate place or state of an event.

do--via->thing
occur--via->thing

Examples and readings

2.1.3 Attributes

Attributes are mainly for the purpose to describe the subjectivity information of sentences. We adopt the attributes set of the UNL. They show what is said from the speaker's point of view: how the speaker views what is said. This includes phenomena technically called "speech acts", "propositional attitudes", "truth values", etc. Attributes are also used to express the range of concepts such as the concept indicate generic type of concept and so forth. This time, we newly introduce attributes to express logical expressions in order to strengthen the expressibility of the CWL.

Relations and concepts are used to describe the objectivity information of sentences. Attributes modify concepts including hyper node (compound concepts) to indicate subjectivity information such as about how the speaker views these states-of-affairs and his attitudes toward them and to indicate the property of the concepts.

Attributes are divided into the following groups:

• Describing logic characters / properties of concepts
• Times with respect to the speaker
• Speaker's view on aspects of event
• Speaker's view of reference to concepts
• Speaker's view of emphasis, focus and topic
• Speaker's attitudes
• Speaker's feelings and judgments

Attribute:
    attribute of concept
        attribute of nominal concept
        attribute of predicative concept
            aspect (view on aspects of event)
                begin          :beginning of an event or a state
                complete       :finishing/completion of a (whole) event
                continue       :continuation of an event
                custom         :customary or repetitious action
                end            :end/termination of an event or a state
                experience     :experience
                progress       :an event is in progress
                repeat         :repetition of an event
                state          :final state or the existence of the
                                object on which an action has been taken
            time (with respect to speaker)
                past           :happened in the past
                present        :happening at present
                future         :will happen in future
            view of emphasis, focus and topic
                contrast       :contrasted concept
                emphasis       :emphasized concept
                entry          :entry or main UW of a sentence or a scope
                qfocus         :focused concept of a question
                theme          :instantiates an object from a different class
                title          :title
                topic          :topic
            attitudes(modality)
                affirmative    :affirmation
                confirmation   :confirmation
                exclamation    :exclamation
                humility       :in a humility manner
                imperative     :imperative
                interrogative  :interrogation
                invitation     :inducement
                polite         :polite way
                request        :request
                respect        :respectful way
                vocative       :vocative
            feelings and judgments
                ability        :ability, capability of doing something
                get-benefit    :speaker's feeling of receiving
                                benefits through the fact or result of
                                something (to be) done by somebody else
                give-benefit   :speaker's feeling of giving benefits
                                by doing something for somebody else
                conclusion     :logical conclusion due to a certain condition
                consequence    :logical consequence
                sufficient     :sufficient condition
                consent        :consent feeling of the speaker about something
                dissent        :dissent feeling of the speaker about something
                grant          :to give/get consent/permission to do something
                grant-not      :not to give consent to do something
                although       :something follows against [contrary
                                to] or beyond expectation
                discontented   :discontented feeling of the speaker
                                about something
                expectation    :expectation of something
                wish           :wishful feeling, to wish something is
                                true or has happened
                insistence     :strong determination to do something
                intention      :intention about something or to do something
                want           :desire to do something
                will           :determination to do something
                need           :necessity to do something
                obligation     :obligation to do something according
                                to (quasi-) law, contract, or …
                obligation-not :obligation not to do something, forbid
                                to do something according to (quasi-)
                                law, contract or …
                should         :to do something as a matter of course
                unavoidable    :unavoidable feeling of the speaker
                                about doing something
                certain        :certainty that something is true or happens
                inevitable     :logical inevitability that something
                                is true or happens
                may            :practical possibility that something
                                is true or happens
                possible       :logical possibility that something is
                                true or happens
                probable       :(practical) probability that something
                                is true or happens 
                rare           :rare logical possibility that
                                something is true or happens
                unreal         :unreality that something is true or happens
                admire         :admiring feeling about something
                blame          :blameful feeling about something
                contempt       :contemptuous feeling about something
                regret         :regretful feeling about something
                surprised      :surprised feeling about something
                troublesome    :troublesome feeling about occurrence
                                of something
            logicality
                transitive     :has transitivity
                symmetric      :has symmetricity
                identifiable   :can identify the subject
                disjointed     :all element concept have no common
                                instance all connected concept do not
                                share instances
            view of reference
                generic        :generic concept
                def            :already referred
                indef          :non-specific class
                not            :complement set
                ordinal        :ordinal number
            modifying attribute on aspect
                just           :expresses an event or a state that has
                                just begun or ended/completed
                soon           :expresses an event or a state that is
                                about to begin or end/completed
                yet            :expresses an event or a state that has
                                not yet started or ended/completed,
                                together with not

2.1.3.1 Time with respect to the Speaker

Where does the speaker situate his description in time, taking his moment of speaking as a point of reference? A time before he spoke? After? At approximately the same time? This is the information that defines "narrative time" as past, present or future. These Attributes are attached to the main predicate.

Although in many languages this information is signaled by tense markings on verbs, the concept is not tense, but "time with respect to the speaker:. The clearest example is the simple present tense in English, which is not interpreted as the present time, but as "independently of specific times".

Consider the example:

The earth is round.

This sentence is true in the past, present and future, independently of the speaker's time, so although the tense is "present" it is not interpreted as the present time.

2.1.3.2 The Speaker's View of Aspect

A speaker can emphasize or focus on part of an event or treat it as a whole unit. This is closely linked to how the speaker places the event in time. These Attributes are attached to the main predicate.

The speaker can focus on the beginning "begin" of the event, looking forward to it "begin.soon", or backward to it "begin.just".

He can also focus on the end "end" or completion "complete" of the event, looking forward to it "end.soon" or "complete.soon", or backward to it "end.just" or "complete.just".

He can focus on the middle "progress" or continuation "continue" of the event.

The speaker can choose to focus on the lasting effects or final state of the event "state" or on the event as a repeating unit "repeat", experience "experience" or custom "custom".

He can also focus on the incompleteness or the fact that it has not yet happened, by using "yet".

These attributes are used to modify the attributes above, to express a variety of aspects of natural languages.

2.1.3.3 Reference to the range of a concept

Whether an expression refers to a single individual, a small group or a whole set is often not clear. The expression "the lion" is not sufficiently explicit for us to know whether the speaker means "one particular lion" or "all lions". Consider the following examples:

The lion is a feline mammal.
The lion is eating an antelope.

In the first example, it seems reasonable to suppose that the speaker understood "the lion" as "all lions", whereas in the second example as "one particular lion".

The following Attributes are used to make explicit what the speaker's view of reference seems to be.

These attributes are usually attached to UWs that denote things.

2.1.3.4 The Speaker's View of Emphasis, Focus and Topic

The speaker can choose to focus or emphasize parts of a sentence to show how important he thinks they are in the situation described. This is often related to sentence structure.

One concept marked with "entry" is essential for each CWL expression or in a compound concept.

2.1.3.5 The Speaker's Attitudes

The speaker can also express, directly or indirectly, what his attitudes or emotions are towards what is being said or whom it is being said to. This includes respect and politeness towards the listener and surprise toward what is being said.

2.1.3.6 The Speaker's Feelings, Judgement and Viewpoint

These attributes express the speaker's feelings or how the speaker views or judges what is said.

This sort of subjective information is very much dependent on the type of language. It should be possible to express every kind of subjective information from all languages. Thus, the development of the attributes is open to the developers of each language, who can introduce a new attribute when no current attribute expresses its meaning. The new attribute must be also introduced in the same way.

The following attributes are used to clarify the speaker's viewpoint information.

• Ability

  ability	Ability, capability of doing something ex) The child can 't walk yet. ex) He can speak English but he can't write it very well.

• Beneficialty

  get-benefit	Speaker's feeling of receiving benefits through the fact or result of something (to be) done by somebody else ex) I'll have my secretary type the letter. *In Japanese the auxiliary verb of `~te morau' is used to express the getting benefits feeling. For instance it is frequently used in a sentence in the sense of `to have somebody do something' in Japanese.
  give-benefit	Speaker's feeling of giving benefits by doing something for somebody else ex) Be kind to old people. *In Japanese the auxiliary verb of `~te ageru' is used to express the giving benefits feeling. For instance it is frequently used in a sentence in the sense of `Be kind to old people' in Japanese.

• Conclusion

  conclusion	Logical conclusion due to a certain condition ex) He is her husband; she is his wife.
  consequence	Logical consequence ex) He was angry, wherefore I left him alone.

• Condition

  sufficient	Sufficient condition ex) only have to

• Consent and dissent

  consent	Consent feeling of the speaker about something
  dissent	Dissent feeling of the speaker about something ex) But that's not true.
  grant	To give/get consent/permission to do something ex) Can I smoke in here? ex) You may borrow my car if you like.
  grant-not	Not to give consent to do something ex) You {mustn't/are not allowed to/may not} borrow my car.

• Expectation

  although	Something follows against [contrary to] or beyond expectation ex) Although he didn't speak, I felt a certain warmth in his manner.
  discontented	Discontented feeling of the speaker about something ex) (I'll tip you 10 pence.) But that's not enough!
  expectation	Expectation of something ex) Children ought to be able to read by the age of 7. ex) If you leave now, you should get there by five o'clock.
  wish	Wishful feeling, to wish something is true or has happened ex) If only I could remember his name! (~I do wish I could remember his name!) ex) You might have just let me know.

• Intention

  insistence	Strong determination to do something ex) He will do it, whatever you say.
  intention	Intention about something or to do something ex) He shall get this money. (Speaker's intention) ex) We shall let you know our decision.
  want	Desire to do something ex) I want to go France.
  will	Determination to do something ex) I'll write as soon as I can. ex) We won't stay longer than two hours.

• Necessity and obligation

  need	Necessity to do something ex) You need to finish this work today. ex) I must be going now. ex) I always have to work hard.
  obligation	Obligation to do something according to (quasi-) law, contract, or … ex) The vendor shall maintain the equipment in good repair. ex) You must come by nine.
  obligation-not	Obligation not to do something, forbid to do something according to (quasi-) law, contract or … ex) Cars must not park in front of the entrance. ex) No smoking
  should	To do something as a matter of course ex) You should do as he says. ex) You ought to start at once.
  unavoidable	Unavoidable feeling of the speaker about doing something ex) I could not help speaking the truth.

• Possibility

  certain	Certainty that something is true or happens ex) If Peter had the money, he would have bought a car. ex) They should be home by now.
  inevitable	Logical inevitability that something is true or happens ex) All living things must die.
  may	Practical possibility that something is true or happens ex) It may be true. ex) It could be.
  possible	Logical possibility that something is true or happens ex) Anybody can make mistakes. ex) If Peter had the money, he would buy a car.
  probable	(Practical) probability that something is true or happens ex) That would be his mother. ex) He must be lying.
  rare	Rare logical possibility that something is true or happens ex) If such a thing should happen, what shall we do? ex) If I should fail, I will [would] try again.
  unreal	Unreality that something is true or happens ex) If we had enough money, we could buy a car. ex) If Peter had the money, he could buy a car.

• Emotion

  admire	Admiring feeling of the speaker about something
  blame	Blameful feeling of the speaker about something ex) A sailor, and afraid of the sea!
  contempt	Contemptuous feeling of the speaker about something ex) You never could do it *In Japanese the postpositional particles of `nado', `nanka' or `nante' as in `kimi nado niha..' can be used to express the contemptuous feeling of the speaker about the target, mainly in a negative sentence
  regret	Regretful feeling of the speaker about something ex) It's a pity that he should miss such a golden opportunity.
  surprised	Surprised feeling of the speaker about something ex) (He has succeeded!) But that's great!
  troublesome	Troublesome feeling of the speaker about the occurrence of something ex) My house was [I had my house] broken into.@troublesome yesterday. *There is a troublesome feeling of the speaker when using a passive form of the verb in this case in Japanese.

2.1.3.7 Convention

Typical CWL structures can be expressed by attributes to avoid the complexity of enconverting and deconverting. What marks are used for enclosing a word or phrase can also be expressed by attributes. The attributes for indicating enclosure must be attached to the scope node of the enclosed phrase if it consists of a (set of) binary relation(s) of CWL.

2.2 CWL platform

As we do not have any system for CWL at this moment, we need to use the UNL system for input CWL and output what is expressed in CWL in natural languages. We basically use the UNL system as a platform of CWL.

The CWL platform consists of CWL Editor, CWL converter and the UNL System consisting of Enconverter (which convert natural languages into UNL), Deconverter (which convert UNL into natural languages).

Since compatibility of the three types of expression of CWL.unl, CWL.cdl, CWL.rdf, The UNL system together with conversion system allow people to make web pages in CWL.unl, CWL.cdl, CWL.rdf and also allow people to see those web pages in their mother tongues.

Beside the UNL system, we provided conversion system (CWL converter) among CWL.unl, CWL.cdl and CWL.rdf. And also we provide necessary vocabulary for CWL based on the UNLKB which provides semantic background of Universal Words of UNL. Knowledge on words (CWL ontology) of each language is stored in UNLKB (CWL.unl), CDD.nl (CWL.cdl) and OWL (CWL.rdf).

3. CWL.unl

The UNL is an acronym for `Universal Networking Language'.  The CWL.unl is a prepsentation of CWL in UNL. The UNL including UNLKB and UWs was developed under United Nations University / Institutes of Advanced Sturdy in 1996, and research and development were transferred to the UNDL Foundation in 2001.(http://www.undl.org/unlsys/uw/unlkb.htm)

3.1 UNL

The UNL expresses information or knowledge in the form of semantic network with hyper-node. UNL semantic network is made up of a set of binary relations, each binary relation is composed of a relation and two UWs that hold the relation. A binary relation of UNL is expressed in the following format:

<relation> (  <uw1>, <uw2> )

In <relation>, one of the relations defined in the UNL Specifications is described. In <uw1> and <uw2>, the two UWs that have the relation given by <relation> are described. Semantic network of UNL expression is a directed graph by means of the binary relations with direction. The three elements of each binary relation have the following interrelationship:

<uw1> – <relation> → <uw2>

Such a binary relation is interpreted as that:

the UW given in <uw2> plays the role indicated by the relation given in <relation> held by the UW given in <uw1>; whereas the UW given in <uw1> holds the relation given in <relation> with the UW given in <uw2>.

A UNL expression is a hyper semantic network. That is, each node of the graph, <uw1> and <uw2> of a binary relation, can be replaced with a semantic network. Such a node consists of a semantic network of a UNL expression and is called a `scope'. A scope can be connected with other UWs or scopes. The UNL expressions in a scope is distinguished from others by assigning an ID to the <relations> of the set of binary relations that belong to the scope.

The general description format of binary relations for a hyper-node of UNL expression is the following:

<relation> : <scope-id> ( <node1>, <node2> )

Where,

• <scope-id> is the ID for distinguishing a scope.
• <scope-id> is not necessary to specify when a binary relation does not belong to any scope.
• <node1> and <node2> can be a UW or a <scope node>.
• A <scope node> is given in the format of `:<scope-id>'.

3.1.1 UNL Document

UNL expressions are provided in the format of UNL documents. A UNL document is a text file that includes the original sentences, UNL document tags, UNL expressions and etc.

A UNL document is enclosed with tags `[D:<dinf>]' and `[/D]'. Within these tags, each paragraph is enclosed with a pair of tags `[P:<p_num>]' and `[/P]', and each sentence is enclosed with a pair of tags `[S:<s_num>]' and `[/S]'. Inside a sentence, the source text is enclosed with `{org:<l_tag>}' and `{/org}', its UNL expression is enclosed with `{unl:<uinf>}' and `{/unl}'. Sentences of target languages can also be stored in the UNL document. Each target sentence is enclosed with a pair of language tags `{<l_tag>}' and `{</l_tag>}' following the UNL expression of each sentence.

Description format of a UNL document is the following:

The tags used in a UNL document are the following:

See the following section about <UNL expression>.

3.1.2 UNL Expression

A UNL expression of a sentence is identified with the following tags: {unl} and {/unl}.

Any component, such as a word, phrase and, of course, a sentence of a natural language can be represented with UNL expressions. A UNL expression therefore consists of a UW or a (set of) binary relation(s). In UNL documents, a UNL expression for a sentence is enclosed by the tags {unl} and {/unl} inside [S] and [/S]. If a UNL expression consists of a UW, this UW should be enclosed further by the tags [W] and [/W]. If necessary, the whole sentence can also be expressed as a scope. In this case, the Compound UW-ID of the scope should be enclosed by [W] and [/W].

There are two forms for expressing UNL expressions, one is the table form and the other is the list form. The table form is made up of a set of binary relations, and each binary relation is expressed by connecting the two related UWs directly. And the list form is divided into two parts: a list of UWs corresponding IDs and a list of binary relations described by the IDs. The table form of a UNL expression is more readable than the list form, but the list form of a UNL expression is more compact than the table form. These two forms are convertible with each other.

3.1.2.1 The table form of UNL expression

• A UNL expression consists of a set of binary relations:

  {unl}
  <binary relation>
  ...
  {/unl}
  

• A UNL expression consists of a UW:

  {unl}
  [W]
  <UW><attribute list>
  [/W]
  {/unl}
  

• A UNL expression consists of a scope:

  {unl}
  [W]
  ":" <compound UW-ID><attribute list>
  [/W]
  <binary relation>
  ...
  {/unl}
  

Each tag and binary relation should end with a return code: `0x0a'.

Syntax of binary relation

Description format of a binary relation of the table form is the following:

Compound UW-ID

A UNL expression can include more than one scope. Compound UW-IDs are for identifying each concept specified by compound UWs (scopes) in a UNL expression. A scope is a group of binary relations that can be referred to as a UW by indicating its compound UW-ID in the format of `:<Compound UW-ID>'. A node described in this way in the UNL expression network that refers to a scope is called a `Scope Node'. For details about the scope please refer to `3.2 Compound UWs'.

UW-ID

UW-IDs are for identifying each concept specified by UWs in a UNL expression. If a UW appears in a UNL expression more than once and means different concepts (things or events), a unique UW-ID must be given to each concept of the UWs.

The following shows an example of UNL expressions of the sentence `I can hear a dog barking outside':

{unl}
agt(hear(icl>perceive(agt>person,obj>thing)).@entry,    I)
obj(hear(icl>perceive(agt>person,obj>thing)).@entry,    :01)
agt:01(bark(agt>dog).@entry,    dog(icl>canine))
plc:01(bark(agt>dog).@entry,    outside(icl>place))
{/unl}

In above UNL expression, `agt', `obj' and `plc' are relation labels, `I', `bark(agt>dog)', `dog(icl>canine)', `hear(icl>perceive(agt>person,obj>thing))' and `outside(icl>place)' are UWs. `a dog barking outside' is expressed by a scope, and `01' is given as the compound UW-ID to the scope. `:01' appears in the position of a UW is the scope node to refer to the scope. Binary relations indicated by the Compound UW-ID define the contents of the scope.

3.1.2.2 The list form of UNL expression

The list form of a UNL expression consists of a set of UWs and a set of encoded binary relations (expressed by UW-IDs) of a sentence. In case a whole sentence is treated as a scope, the Compound UW-ID of the scope for the sentence can be included in the UW list between [W] and [/W].

{unl}
[W]
{<UW> | {`:'<compound UW-ID>}}[<attribute list>]":" <UW-ID>
…
[/W]
[R]
<binary relation by UW-IDs>
…
[/R]
{/unl}

The tags used above have the following meanings.

Each tag, encoded binary relation and UW should end with a return code: `0x0a'.

UW List

UWs of a UNL expression must be listed between [W] and [/W] with different (unique) UW-IDs for different concepts. This means that the same UW expression but expressing different concepts (instances) must be given different UW-IDs. A scope must be defined again in the UW list.

Syntax of an encoded binary relation

For instance, the following shows an example of the list form of a UNL expression of the sentence `I can hear a dog barking outside'.

{unl}
[W]
I:01
hear(icl>perceive(agt>person,obj>thing)).@entry:02
dog(icl>canine):03
bark(agt>dog).@entry:04
outside(icl>place):05
:01:06
[/W]
[R]
02aoj01
02obj06
04agt:0103
04plc:0105
[/R]
{/unl}

In the above example, between [W] and [/W], UWs 'I', 'hear(icl>perceive(agt>thing,obj>thing))', 'dog(icl>canine)', 'bark(agt>dog),' 'outside(icl>place)' and the scope node `:01' are given a UW-ID from 01 to 06 respectively.

Between [R] and [/R], binary relations are described using the UW-IDs defined in the UW list. For example, `02obj06' in the second line shows that the concept identified by UW-ID 06 is the 'obj' of the concept identified by UW-ID 02. UW-ID 06 means the concept of scope 01, and UW-ID 02 means the concept of 'hear(icl>perceive(agt>thing,obj>thing))'.

Binary relations `04agt:0103' and `04plc:0105' express the UNL expression of scope 01. This is indicated by the CompoundUW-ID `01' described following the relations 'agt' and 'plc'.

qua [":"<Compound UW-ID>] "(" {<UW1>|":" <Compound UW-ID>} "," {<UW2>|":"<Compound UW-ID>} ")"

3.4.1 UWs

3.4.1.1 Syntax of UW

A UW is made up of a character string (an English-language word) followed by a list of constraints. The meaning and function of each of these parts is described in the next section, on Interpretation.

The following is the syntax of description of UWs:

3.4.1.2 Interpretation

Headword

The headword is an English word/compound word/phrase/sentence that is interpreted as a label for a set of concepts: the set made up of all the concepts that may correspond to that in English. A Basic UW (with no restrictions or constraint list) denotes this set. Each Restricted UW denotes a subset of this set that is defined by its constraint list. Extra UWs denote new sets of concepts that do not have English-language labels.

Thus, the headword serves to organize concepts and make it easier to remember which is which.

Constraints or Restrictions

The constraint list restricts the interpretation of a UW to a subset or to a specific concept included within the Basic UW, thus the term `Restricted UWs'. The Basic UW `drink', without a constraint list, includes the concepts of `putting liquids in the mouth', `liquids that are put in the mouth', `liquids with alcohol', `absorb' and others. The Restricted UW 'drink(agt>thing,obj>liquid)' denotes the subset of these concepts that includes `putting liquids in the mouth', which in turn corresponds to verbs such as `drink', `gulp', `chug' and `slurp' in English.

A restriction of a UW is made up of a pair of a relation and a pre-defined UW (or part expression of a pre-defined UW) that holds the relation with this UW. If more than one restrictions are necessary, a comma `,' should be used between restrictions.  A Restricted UW is defined through a Master Definition (for details please refer to UW Manual). In a Master Definition, full expressions of pre-defined UWs must be described in the restrictions, whereas as for a UW, if and only if the uniqueness can be kept, part of the pre-defined UWs (its headword or part restrictions) can be used in the restrictions.  Relation labels used in the constraint list must be defined in the UNL specifications and should be sorted in alphabetical order if more than one restrictions are used.

In order to define the meaning of a UW more accurately, for instance, a subset concept of UW is always defined under an upper UW that has the closest but more general meaning. This is implemented by linking the UW to be defined with the upper UW using 'icl' relation.  For example, UW 'provide(icl>give(agt>thing,gol>thing,obj>thing))' is defined as a subset concept of UW 'give(agt>thing,gol>thing,obj>thing)'.  However if the headword of the upper UW is either of `be', `do', `occur' and `uw', such a headword is not necessary to remain in the restrictions of lower UWs as the each set of restrictions of these upper UWs is set enough to restrict their lower UWs.  For example, from Master Definition 'drink({icl>do(}agt>thing,obj>liquid{)})' a UW 'drink(agt>thing,obj>liquid)' and a binary relation 'icl(drink(agt>thing,obj>liquid), do(agt>thing,obj>liquid))' are generated. The part related to the headword `do' is removed from its lower UW expression and the binary relation that will be described in the UNLKB shows that 'drink(agt>thing,obj>liquid)' is a subset concept of 'do(agt>thing,obj>liquid)'.  For details of description of UW please refer to UW manual.

3.4.1.3 Types of UW

A UW is a character string and most of the UWs are basically made up of an English expression with restrictions. A UW can express various levels' concepts depending on the restrictions and can be used to express a more specific or particular concept or an instance by giving attributes and IDs or restrictions from other UNL expressions. The UWs are divided into four types:

• Basic UWs, which are bare headwords with no constraint list, for example:

  go
  take
  house
  state
  

• Restricted UWs, which are headwords with a constraint list, for example:

  state(icl>express(agt>thing,gol>person,obj>thing))
  state(icl>country)
  state(icl>region)
  state(icl>abstract thing)
  state(icl>government)
  

• Extra UWs, which are a special type of Restricted UW, for example:

  ikebana(icl>flower arrangement)
  samba(icl>dance)
  souffle(icl>food)
  

• Temporary UWs, which are not necessary to define, for example:

  1234
  xyz
  

Basic UWs

Basic UWs are character strings that correspond to English words. Such a basic UW denotes all the concepts that may correspond to those in English.  However a basic UW is not used if the English expression is ambiguous.  Such a basic UW is usually used as the headwords of Restricted UWs for its various specific concepts.  A basic UW is used if the English expression has no ambiguity.

Restricted UWs

Restricted UWs are by far the most important. A Restricted UW is made up of a headword (English expression) with restrictions. It is necessary when the English expression of headword has broader sense (more meanings) than the concept aimed to define. The restrictions restrict the range of the concept that an English expression represents. Each Restricted UW made from an English expression represents a more specific or particular concept, or a subset of the concepts of the English expression.

For example, following are the Restricted UWs made from the English word `state':

• state((icl>express(agt>thing,gol>person,obj>thing)) is a more specific concept that denotes an action in which humans express something.
• state(icl>country) is a more specific sense of `state' that denotes a country.
• state(icl>region) is a more specific sense of `state' that denotes a region of a country.
• state(icl>abstract thing) is a more specific sense of `state' that denotes a kind of condition that persons or things are in. This UW is defined as a more general concept that can be referred to when defining other synonymous UWs, such as `situation' or `condition'.
• state(icl>government) is a more specific sense of `state' that denotes a kind of government.

The information in parentheses is the constraint list and it describes some conceptual restrictions; this is why they are called Restricted UWs. Informally, the restrictions mean `restrict your attention to this particular sense of the word'.

Extra UWs

Extra UWs denote concepts that are not found in English and therefore have to be introduced as extra categories. Foreign-language words are used as headwords using English (Alphabetical) characters.

For example, following are the examples of Extra UWs:

• ikebana(icl>flower arrangement) is `a kind of flower arrangement' for the meaning of `something you do with flowers',
• samba(icl>dance) is `a kind of dance', and
• souffle(icl>food) is `a kind of food'.

To the extent that these concepts exist for English speakers, they are expressed with foreign-language loanwords and do not always appear in English dictionaries. So they simply have to be added to be able to use these specific concepts in the UNL system. The restrictions give the idea of what kind of concept is associated with these Extra UWs and the constraints provide the binary relations between this concept and other, more general, concepts already defined. Needless to say, an Extra UW is also defined through a Master Definition, and a pre-defined UW or its part expression must be used in the restrictions of an Extra UW.

Temporary UWs

A number or an address of email that has to be used as it is not necessary to define. They can appear in a UNL document and are treated as temporary UWs.

ex) 1234
    xyz

3.4.2 Compound UWs : Scopes

Compound UWs are a set of binary relations that are grouped together to express a complex concept. A sentence itself is considered as a compound UW. Compound UWs denote complex concepts that are to be interpreted/understood as a whole so that one can talk about their parts all at the same time. A compound UW is expressed by a scope in UNL expressions. A scope makes it possible when a compound UW is necessary to be connected with other UWs.

Consider the following example:

[Women who wear big hats in movie theaters] should be asked [to leave].

The part of the sentence within square brackets is what should be asked. Only when they are grouped together and considered as a whole unit can the correct interpretation be obtained.

Attributes can be attached to them to express negation, speaker attitudes, etc., which are usually interpreted as modifying the main UW (attached with @entry) and its coordinate UWs within the compound UW (scope).

3.4.2.1 The way to define a Compound UW

A Compound UW is defined by placing a Compound UW-ID immediately after the Relation Label in all of the binary relations that are to be grouped together. Thus, in the example below, `:01' indicates all of the elements that are to be grouped together to define Compound UW number 01.

agt:01(wear(aoj>thing,obj>hat), woman(icl>person).@pl)
obj:01(wear(aoj>thing,obj>hat), hat(icl>wear))
aoj:01(big(aoj>thing), hat(icl>wear))
plc:01(wear(aoj>thing,obj>hat), theater(icl>facilities))
mod:01(theater(icl>facilities), movie(icl>art))
agt:01(leave(agt>thing,obj>place).@entry, woman(icl>person).@pl)

After this group has been defined, wherever the Compound UW-ID is, for instance `01' in the above example, it can be used to cite the Compound UW. The way to cite a Compound UW is explained in the next section.

A Compound UW is considered as a sentence or sub-sentence, so in the definition of a Compound UW one entry node marked by @entry is necessary.

3.4.2.2 The way to cite a (Compound) UW

Once defined, a Compound UW can be cited or referred to by simply using the Compound UW-ID as an UW.  The method is to indicate the Compound UW-ID following a colon `:'. The reference to a Compound UW is also called a Scope Node.  The Scope Node has the following syntax:

To complete the UNL expression of `[Women who wear big hats in movie theaters] should be asked [to leave]', the following are necessary:

obj(ask(agt>thing,gol>person,obj>uw).@should.@entry, :01)
gol(ask(agt>thing,gol>person,obj>uw).@should.@entry, woman(icl>person).@pl.@topic)

'obj(ask(agt>thing,gol>person,obj>uw).@should.@entry, :01)' shows that Scope 01 is the obj of `ask'.

':01' shows the scope node. It is interpreted as the whole set of binary relations defined above. It means that `:01' should be understood as comprising all of these binary relations.  Compound UWs can be cited within other Compound UWs.

3.5 UNL Knowledge Base (UNLKB)

The UNLKB is a semantic network comprising every directed binary relation between UWs. All the binary relations of the UNL KB are in the following format: 'relation(UW1, UW2)=c', where 'c' is the degree of certainty, which has the value 0 (impossible) or 1 to 128 (certain). This binary relation means `UW1 takes UW2 as the relation in certainty value c', or `UW2 plays the role specified by relation for UW1 in certainty value c'.

The UNLKB Defines Concepts of UWs

The UNLKB provides concepts and UW of the concepts. A UW (Universal Word) is a label for a concept. Concepts labelled by UWs are defined by describing the set of possible relations that each concept can have with other concepts.  Definitions of possible relations with other concepts describe behaviours of concepts in terms of other concepts. This behaviour is the property of a concept in the sense that the descriptions of behaviour characterize the concept and provide enough information to understand the semantic structure of the sentence.

The UNLKB Provides Linguistic Knowledge of Concepts

The behaviour of a concept is considered as linguistic knowledge on the concept. This knowledge is used to provide semantic structure of sentences of natural languages. For example, an `author' is a `person', which can take various actions that a person can take such as a person can writes something and something can be a book, and so forth. This level of knowledge is necessary to provide semantic background of natural language sentences. Further knowledge, for example real world knowledge and so forth, will be established based on this linguistic knowledge using the UWs.

UW System

In the UNL KB, all UWs are linked with each other through 'icl',(subclass) 'iof'(element/instance), or 'equ' relations. 'Icl' links a UW of a subclass concept to a super-class concept UW; 'iof' links a UW expressing an instance to a UW of a class concept; The UWs related to each other through 'icl', 'iof' and 'equ' relations make up a hierarchy of UWs. This hierarchy of UWs is the UW system. This UW system allows having multiple super-class concepts. Accordingly, the UW system is a lattice type of network.

The hierarchy of the UW system is constructed by taking the property inheritance and replacement by super-class concept mechanisms into consideration. In UW system, lower UWs inherit the properties of upper UWs; and upper UWs can replace lower UWs to convey a more general sense in the specific context of the lower UWs. All these inheritance and replacement are carried out through the relations 'icl', 'iof' and 'equ'.

In the UNL KB, all possible relations, such as 'agt', 'obj', etc, that an UW can have with others are defined for each. Every possible relation is defined between the two most general UWs of the two categories (of lower UWs) that can have the relation. Utilizing the property inheritance mechanism of the UW system possible relations of lower concepts are deductively inferred and this inference mechanism can reduce the number or binary relations.

Replacement of lower UWs by upper UWs can cause problems by introducing ambiguities if the upper UWs are not close in meaning to the lower UWs. To avoid this, the upper UWs must be the closest UWs among all of the more general UWs . In other word, every UW must be positioned under the closest upper UWs.

The UNLKB defines the syntax and semantics of the language UNL. In the UNL System, UNLKB is used in sentence analysis for disambiguation and in sentence generation for finding more general concepts when encountering unknown concept to the language. The UNLKB also is used to verify UNL expressions since it provide syntax and semantics of UNL.

4. CWL.cdl

The CWL.cdl is a representation of CWL in CDL.nl. The CDL.nl is appropriate for logical treatment of contents together with information in multimedia. The UNL is appropriate for communication beyond language barriers. RDF/OWL is appropriate for dealing with meta data of web pages and has already many applications actually working.

Design Principles

Concept Description Language (CDL) is a language that describes a wide variety of representation media and content, as well as conceptualization of their meaning, in a common format. CDL is a simple extension of the basic principles of XML and is able to inherit stored data tagged with XML.

In contrast to XML, which annotates the document structure (syntactic structure) of content, CDL describes the concept structure (semantic structure) of content. This paper begins with the characteristics of CDL compared to those of XML.

Specifications design for XML is summarized as follows.

1. Tags (document tags) are embedded into content and annotate the document structure. There is basically one type of tag.
2. The document structure model has a nesting tree structure.
3. Tag definitions are attached to annotated content and are mutually referred by name space function.
4. There is style sheet that converts tagged document structure into visual presentation which is easy to understand for humans.

The followings are the key concepts of the CDL specification.

1. Labels (concept labels) are used to describe the concept structure separate from content. Labels are divided largely into entity concept labels and relation concept labels.
2. The concept structure model is a hyper network structure.
3. Label definitions are compiled in CDD (concept definition dictionary) separate from all content targeted for description. The semantic relations between concepts described with labels and the internal structure of the concepts are defined in the CDD. The CDD represents the ontology of the concepts.
4. There is a grounding mechanism that converts the concept structure into content that is easy to understand for humans.

It is possible to set up partially a mechanism compliant to CDL for XML. This mechanism is realized by RDF/OWL in the Semantic Web. The following are its key characteristics in RDF/OWL specifications design.

1. `Properties' are described.
2. The properties (meta data) of the resources (including content) are described. Description is in the form of a set of triples, each of which consists of subject (resource), property and property value, in frame-like nesting format.
3. Vocabulary for description is organized in ontology. The framework for describing ontology is the RDF Schema, and OWL is the language for describing definitions.

In comparison, the following are the key CDL specifications.

1. `Structures' are described.
2. The concept structure of the entire content is described. The network format consisting of node and arc, each of which is entity concept and the relation concept (and its degenerate form of attribute and attribute value) is created. Furthermore, complex concept type (hyper node and hyper arc) and elemental concept type are created for each concept.
3. Vocabulary for description is organized in the CDDs. The framework for describing vocabulary definitions (ontology) and meta vocabulary to be described are defined a priori in the CDD of CDL.core. The CDD is the concept ontology with Entity, Relation and Attribute as top-level concepts, and the CDD itself is a complex entity.

In contrast to RDF/OWL which was designed in bottom-up design from XML for metadata description, CDL was designed in top-down approach from the basic perspective on concept structure for the purpose of content concept description. For this reason, CDL is consistent, simple and clear in specifications. In CDL implementation, RDF/OWL implementation specifications and XML implementation specifications are prepared.

In CDL, CDL.xxx for various representation media and the various content formats have to be set up, based on CDL.core, which provides the meta-concepts for describing concept definitions. The respective concept vocabularies are defined in their corresponding CDD (CDD.xxx). For natural language media, concept shared with natural language is defined as CDD.nl. Concepts necessary for the conceptualization of meanings representing terms, phrases, sentences and text in natural language are defined. CDLs corresponding to each language, such as Japanese, English, and Chinese, are created as CDL.jpn, CDL.eng, CDL.chi, etc., and CDDs defining concepts for each language are prepared. Furthermore, CDD corresponding to everyday language, CDD for specialized areas and communities, and CDD for controlled language, etc., are created to prepare CDL that corresponds to a variety of language usage.

In addition, CDLs can also be made for mathematical equations, programming languages, video image, music sound, etc., in the form of CDL.math, CDL.prog, CDL.movie, CDL.music, etc. CDDs therefore consist of concepts inherent to each representation media and concepts borrowed from natural language.

In CDL, maintaining continuity with XML is important. This is because the document structure (syntactic structure) serves as a guide for the concept structure (semantic structure) and it is necessary to appropriately preserve the huge amount of content that is XML-tagged. The schemes prepared for appropriate coordination between CDL and XML are following. There are two schemes.

1. Integration of description and annotation
   The description function is able to include annotation function. CDL is capable of continuous adaptation from annotation to description, such as all annotation, partly annotation and partly description, and all description.
2. Implementation specifications on XML
   In addition to implementation specifications on RDF/OWL, implementation specifications directly on XML will be investigated.

4.1 CDL.core

4.1.1 Model and Syntax Specifications

Model and Syntax determine how concepts or conceptualization are to be modeled and what kind of data format or grammar will be set up to express the model. In order words, it determines the common form of expression for all CDL family languages. Therefore, CDL.core follows this notation format.

First, the basic categories for the model of conceptualization are determined as follows.

Concept
    Entity
        ElementalEntity
        ComplexEntity
    Relation
        ElementalRelation
        ComplexRelation
    Attribute

Concepts and concept descriptions are modeled in the following network structure, namely:

1. Entities that are to make up the concepts become nodes, and the relations between entities become arcs in the network structure.
2. The nodes and arcs are elemental concepts without structure (ElementalEntity and ElementalRelation) or complex concepts with structure (ComplexEntity and ComplexRelation). Complex concepts correspond to hyper-nodes or hyper-arcs, creating a congestion model for concept structures.
3. Complex concepts classify two types of model for conceptualization in accordance with how relations are connected. In other words, if a relation is connected with the complex concept as a whole, the model determines the whole as a single concept. If a relation is connected with a concept inside the complex concept, the model determines the concept as a concept modified by the complex concept.
4. Attribute-value pairs are added to the concept description to create model for localized property descriptions of the concept. An attribute is a degenerated Element Relation, and its value is a degenerated Element Entity.

Text Notation

As method for network structure notation for concepts, graph notation with diagram and text notation with symbolic text are made available. Text notation syntax, specifically basic syntax, is shown below. The following four meta symbols are used to describe grammar.

ConceptDescription ::= EntityDescription

EntityDescription ::= ElementalEntityDescription | ComplexEntityDescription
ElementalEntityDescription ::=
    {RealizationLabel  DefinitionLabel  AttributeValuePair… ;}
ComplexEntityDescription ::=
    {RealizationLabel  DefinitionLabel  AttributeValuePair… ;
        EntityDescription… RelationDescription… Arc…}

RelationDescription ::=
    ElementalRelationDescription | CompexRelationDescription
ElementalRelationDescription ::=
    {RealizationLabel  DefinitionLabel  AttributeValuePair… ;}
CompexRelationDescription ::=
    {RealizationLabel  DefinitionLabel  AttributeValuePair… ;}
        From To EntityDescription…EntityDescription… Arc…}

AttributeValuePair ::= Attribute =Value
Arc ::= [EntityRealizationLabel-from RelationRealizationLabel EntityRealizationLabel-to]

RealizationLabel ::= #ArbitraryCharacterString
DefinitionLabel ::= DefinitionLabelDefinedInCDD
Attribute ::= AttributeDefinedInCDD
Value ::= ValueDefinedInCDD

In both entity and relation, concept description is unified, simple and clear. The difference between elemental concept and complex concept is whether there is a structure description after the delimiter (;). The ComplexRelationDescription includes special ElementalEntity (From and To) to match the inside and the outside of an arc.The reason of the use of "{" and "}" is to perceive element set in structure description as bag (set). Therefore, concept description in structure description will be identified uniquely with realization label. Scope can be set on the realization label according to nested structure of concept description. The scope on the realization lablel is set in open scope and closed scope modes. Open scope is default. Description examples hereafter are shown in open scope. The arcs are in triples with direction from left to right.

There are elemental concept description and complex concept description in concept description. One definition is used in various realizations. Concept description requires localized Attribute-Value pair. These are easy to understand for entity concept but require explanation for relation concept. To understand the explanation, the description in the next and subsequent chapters is necessary. However, it will be summarized below.

1. Complex Relation: Relation concept including RDF/OWL is not intended to have structure. However, any relation does not necessarily remain primitive or uniform, and various levels of relations are used. In such a case, a scheme to describe macro relation with micro relation is extremely useful. For example, description of <employer> and <employee> relation with internal structure describing "someone employs someone" and "someone is employed by someone" is useful.
2. Usefulness of Attribute-Value pair in relation concept: A scheme Attribute-Value pair that describes the modality of relation completeness (necessity or possibility, variety such as whether it is established constantly or wha