UsingOntoBuilderforOntologyCreation.docx

UsingOntoBuilderforOntologyCreation.docx

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UsingOntoBuilderforOntologyCreation

UsingOntoBuilderforOntologyCreation

Author:

GiovanniModica

Date:

10/25/2018

1.BrowsingFeaturesofOntoBuilder

OntoBuilderwasdesignedtoworklikeawebbrowser.Figure1showstheOntoBuilderbrowserinterface.TonavigatetoapagesimplyentertheURLintotheaddressbar（e.g.）andpressenterorclickthe“Go”button.BydefaultOntoBuilderwillusetheHTTPprotocolwhennoprotocolisspecified,soaURLsuchaswillbeautomaticallychangedto.URLscanalsobeenteredbymeansofcommoncopy/pastecommandseitherbyrightclickingontheaddressbarorusingthehot-keysshortcuts;theseshortcutsarecompatiblewiththeMSWindowsstandards（e.g.crtl-Cforcopy,crtl-Vforpaste,etc.）.

Figure1.TheOntoBuilderbrowserinterface.

Oncethe“Go”buttonisclicked,theHTMLpageassociatedwiththeURLwillbedisplayedinthe“HTMLView”panel.OntoBuildermaintainsahistoryofvisitedURLs,whichcanbeaccessedusingacomboboxlistintheaddressbar.Theusercanusethebackwardsandforwardsbuttonsinthetoolboxtonavigatethehistory.Thenumberofentriesinthehistoryislimitedbyanoptioninthetooloptionsdialogasshowninfigure2.Thehistorycanbecleared（allentriesinthehistorywillbedeleted）byclickinginthe“ClearHistory”button.

Figure2.OntoBuilderbrowseroptions.

Othernavigationalaspectscanalsobesetinthe“Browser”optionstab.The“AutomaticMETAnavigation”optionisforpagescontainingredirectionMETAtagssuchasthefollowing:

BycheckingthisoptionOntoBuilderwillautomaticallyloadtheURLspecifiedintheURLattributefortheMETAtag.

TheconnectiontimeoutindicatestheamountoftimetowaitbeforeabandoningaURLconnection.Byspecifying-1sec.,OntoBuilderwillusethesystemdefaultconnectiontimeout.Thisoptionisveryusefulforslowconnectionlinks.

OntoBuildercanalsobedirectedtouseaProxyserverforInternetconnection.Byspecifyingaproxyhostandport,OntoBuilderwillretrieveHTMLpagesthroughtheproxyinsteadofadirectconnection（thedefault）.ThisoptionisveryusefulifrunningOntoBuilderbehindfirewalls.

OntoBuilderhassupportforHTMLcookies,howevercookiesdonotpersistoutsideOntoBuilderwizardsessions.Thismeansthatcookiesarepersistentwhileretrievinganontologyusingtheontologycreationwizard,butoncethewizardfinishestheontologygeneration,anycookieinformationwillbelost.

2.GeneratingOntologies

OncethewebpageforwhichwewanttoextracttheontologyfromisloadedinOntoBuilder,wecanlaunchthe“OntologyCreationWizard”byselectingtheappropriatesubmenucommandunderthe“Ontology”menu,orbyclickingtheappropriateiconintheapplicationtoolbox,orbyusingthehot-keycrtl-W.Inordertoshowhowthewizardworkswewillbuildamulti-page（bymulti-pageontologywemeananontologythatisspreadacrossmultiplepages）ontologyfortheAwebsite.Thefirststepofthewizardisshowninfigure3.

Figure3.Thefirststepoftheontologywizard.

TheontologytitledefaultstothetitleoftheHTMLpageandtheontologynamedefaultstothehostfromwheretheHTMLpageisretrieved.Byclickinginthe“Next:

buttonweopenthe“FormSelection”dialogasshowninfigure4.InthisdialogOntoBuilderwillshowalltheHTMLformsoftheHTMLalongwiththeirinputelements.Sinceonlyoneformcanbesubmittedatatimewhilebrowsingawebpage,theuserisrequiredtoselecttheformhe/shewantstosubmitfromtheformslistedunderthe“”nodeinthe“HTMLElements”panelontheupperleft.NoticethatthispanelshowsahierarchicalviewofalltheontologicalstructuresoftheHTMLpage.

Byclickingonanodeinthe“HTMLElements”panel,alltheattributes（defaultvalue,label,etc.）fortheelementrepresentedareshowninthe“Properties”panelinthelowerleft.IsworthnotingthatforHTMLframepages,theFORMelementswillbelocatedunderthe“”nodeinthe“HTMLElements”panel.

Figure4.The“FormSelection”wizarddialog

The“FormPreview”paneliswheretheuserwillentertherequiredvaluesforformsubmission.InordertodeterminewhattherequiredfieldsarewesuggestsimulatingtheprocessononeoftheInternetbrowserssuchasMSInternetExplorerorNetscapeNavigator.Figure5showstheminimumrequiredvaluesforourAexample.

Figure5.ThereservationprocessinA

ThesameprocessmustbesimulatedinOntoBuilder.Figure6showstheequivalentreservationinOntoBuilder.TheonlydifferenceisthatOntoBuilderdoesn’tsubmittheformbyclickingontheformsubmissionbutton,butinsteadbyclickingthe“Next”buttoninthewizard.

Figure6.ThereservationprocessinOntoBuilder

FailingtodothecorrectsimulationinOntoBuilderwillproduceunexpectedresults（mostofthetimesthewebsitewillreturnapageindicatingthatsomeinformationismissingorreturnanerrorpagewithabriefdescription）.Generallyspeaking,whenusingOntoBuildertoretrieveanontologyfromawebapplication,theusermustsimulatetheuserinteractionasifworkinginacommonbrowser.

Returningtoourexample,therestofthewizardformsarethesame,excepttheywillcontainnewformelementstobeaddedtothefinalontology.Therestoftheprocessisverystraightforwardsowewilljustmentionhowtogettotheend.Therearefourmorepages（i.e.threemorewizarddialogs）toretrievethewholeontology,andinallfourpagesthereisnorequiredfields,defaultvalueswillbeenough.Alltheuserisrequiredtodoistoselecttheappropriateformonthe“HTMLElements”panelandsimulatetheformsubmissionbyclickingonthe“Continue”buttonineachofthenextthreepages.ThelastpagewillallowtoactuallymakethecarreservationinAvis,asshowninfigure7.

Figure7.Laststepintheontologycreationwizard

Duringthewizardoperationtheusercanusethe“Back”buttontogothepreviouslysubmittedform,incaseamistakewasdetected.Oncefinished,thewizardwilldisplaythegeneratedontologyonthe“MainPanel”,asdepictedinfigure8.Thegeneratedontologycanbesavedindifferentformatsbytheappropriatecommandsinthe“File”menu.

Figure8.Thegeneratedontology

3.EnteringtheRightURLsinOntoBuilder

Sometimes,enteringthesameURLusinginacommonbrowserintoOntoBuilderisnotthemostappropriatethingtodo.DuetoOntoBuilderlimitedHTMLrenderingcapabilities,someURLsmaynotbecorrectlydisplayed（andthus,difficulttonavigate）.

Asanexample,considertheAwebsite.ByenteringinOntoBuilderwewillseethatitdoesabadjobinrenderingtheHTMLpage（seefigure9）.NoontologywillbegeneratedfromsuchURL.ItisworthnothingthatnotalwaysabadrenderingoftheHTMLpagemeansthatnousefulontologycouldbegenerated,sometimesOntoBuilderhastroublerenderingtheHTMLpagebutthesourcecodeofitisretrievedcorrectly.Isrecommendedtoruntheontologycreationwizardevenifabadrenderingoccurs,inmostcasesthewizardwillidentifytheformelementseveniftheHTMLrenderingdidn’twork.

Figure9.AnexampleofbadHTMLrenderinginOntoBuilder

Inthesecases,itisadvisedtouseanInternetbrowsertoactuallynavigatetothepagewhereontologicalstructuresmaybeidentified.InthecaseofA,byclickinginthe“Rates&Reservations”buttoninthemenuthebrowserwilldisplaythereservationformundertheURL.Figure10showshowthistimeOntoBuildercorrectlyidentifiestheformelementsinthepage.

Figure10.AnexampleofcorrectHTMLrenderinginOntoBuilder

ForHTMLpagescontainingframes,itmaybeusefulto“break”theframesusingtheURLintheframeset.Asanexample,theURLisaHTMLpagecontainingframes（seetheemptyspaceintheuppersectionofthepageinfigure10）anditssourceisthefollowing:

InthiscaseitmaybebettertoentertheURLforthemainFrameframe（i.e.inOntoBuilder,thus“breaking”theframe.AlthoughOntoBuilderisdesignedtosupportframes（foranexampleloadtheNationalCwebsitetoseethreelevelsofframescorrectlyhandledbyOntoBuilder）,wesuggesttofollowthepreviouspointswhendealingwithframes.

MostcommonInternetbrowserswillallowtoseethesourceofanHTMLpage.ByusingOntoBuilderyoucanenablethe“SourcePanel”tabtoseetheHTMLsourceoftheloadedpage.Forthis,checkthe“SourcePanel”checkboxinthe“View”taboftheOntoBuilderoptionsdialog.

Figure11.ViewoptionsforOntoBuilder

4.TroubleshootingOntologyGeneration

NotallthewebsitesrunassmoothlyastheAsite.Changesareyouwillnotgetacleanontologyatthefirstrun.ThisisduetothecomplexityofmostwebsitesdesignedusingtechnologiesnotsupportedbyOntoBuilder.AtthistimeOntoBuilderdoesn’tsupportanyscriptingatall.Currentwebsitesrelyonscriptingforvalidation,automaticfieldfilling,etc.AsanexampleconsiderapagethathastwofieldsPickupLocationandDropoffLocation,eachwithanassignedhiddenfield.ByusingscriptingthewebpageautomaticallyassignsthekeywordsameinthehiddenfieldfortheDropoffLocation,indicatingthatthedropofflocationwillbethesameofthepickuplocation.AllthisistransparenttotheuserandalsotoOntoBuilder.Ifth