Size: px
Start display at page:

Download ""

Transcription

1 AmyP.Felty1,DouglasJ.Howe1,andFrankA.Stomp2 ProtocolVericationinNuprl? whileretainingexistingadvantagesofthesystem,anddescribesapplicationoftheprovertoverifyingthescicachecoherenceprotocol.the interactivetheoremproveramoreeectivetoolforprotocolverication vericationisbased,inpart,onformalmathematicsimportedfromanothertheorem-provingsystem,exploitingaconnectionweimplemented Abstract.ThispaperpresentsworkdirectedtowardmakingtheNuprl signicantbecausenuprl'spowerfulconstructivetypetheorybuysmuch eectivelyappliedbythesystem'sautomatedreasoningfacilities.thisis annotationschemefornuprl'slogicthatallowstypeinformationtobe betweennuprlandhol.wehavedesignedandimplementedatype 1Introduction ofitsexpressivepowerandexibilityatthecostofgivingupthemore manageablekindsoftypesystemfoundinotherlogics. ofitsmaindistinguishingcharacteristicsisitshighlyexpressiveformallogic,a constructivetypetheorywhoseclassicalvarianthasexpressivepowerequivalent toconventionalsettheory(zfc)[12,6]. Nuprl[2]isaninteractivetheorem-provingsysteminthelineageofLCF.One shallowandrepresentationallysimple. tobeasubstantialadvantageinavarietyofdomains,butlittleworkhasbeen specicallydirectedtowardeectivenessforthekindoflarge-scalepracticalapplicationswherethebulkoftheformalmathematicsishighlycomplicated,but Nuprlhasbeenextensivelyapplied,anditsexpressivepowerhasbeenshown ofnuprltoprovesafetypropertiesofthescicachecoherenceprotocol[8]. Modelcheckingsystemsthathavebeenappliedtotheprotocolsuerfromstate ofthescaleofalgorithmswhichcanbecurrentlyhandledbymechanizedtools. Thispaperdescribesourworkinthisdirection,andfeaturesanapplication explosionatasmallnumberofprocessors,thoughevensosomebugshavebeen found[11].asecondreasonforchoosingitisthataproofmethodandsupported WechoseSCIasanexamplepartlybecauseitscomplexityisrepresentative compromisingexistingadvantagesofthesystemby,e.g.,addingrestrictionsto thelogic.therearethreepartstothiswork. invariantshavealreadybeenworkedout[3].?inproceedingsofthetenthinternationalconferenceoncomputer-aidedverication,june1998. OurworkhasbeentoimproveNuprlforthesekindsofapplicationswithout

2 andmodels.buildingitistime-consuming,andislargelyduplicationofeort sincethesebasicfactstendtobesimilaracrosssystems.toavoiddoingthis quiresagreatdealofbasicformalmathematicsaboutelementarydatastructures ourselves,weimportsomebasicmathematicsfromhol[5],asystemthathas, Importedmathematics.Vericationusinganinteractivetheorem-proverre- applicationtoamoderatelydicultprobleminmetamathematics.ourwork, thoughjustarststep,establishesthatsharingmathematicscanbeusefulin forsoftware/hardwareverication.thepaper[7]givesthebasicdesignofthe connectionbetweenholandnuprl,and[4]givesanextensiontoitandan overtheyears,accumulatedalargecorpusofmathematicsofthekinduseful software/hardwareverication. ditionalaspectsoftypesystems.inparticular,thetypetheory'sexibilityisin largepartduetothefactthattermsareuntypedinthesensethatonecannotdeterminefromthesyntaxofanexpressionwhat,ifany,typeitisamemberof.in thisway,nuprlissimilartosettheory,withtypesbeinganalogoustosets.this TypeAnnotation.Nuprlbuysitsexpressivepoweratthecostofsometra- isaproblemforautomationfortworeasons.first,itisoftenimportantforterms tocomewiththeirtypes;forexample,intermrewriting,typeinformationcan enableausefulformofconditionalrewriting.second,typingpropertiesrequire proof,so,forexample,everytimealemmaisinstantiated,theinstantiatingobjectsmustbeprovedtohavetherighttypes.wehavedesignedandimplemented anannotationschemewheretermsaredecoratedwithtypesinsuchawaythat tunately,theimplementationwasn'tcompleteduntilpart-waythroughthesci typescan(almostalways)beecientlymaintainedduringinference,butnonew of10speedupintermrewriting(themainworkhorseinnuprlproofs).unfor- syntacticrestrictionsareplacedonthelogic.wehaveobtainedroughlyafactor toimplementasuiteofautomatedreasonersspecializedtothismodel. kindofembeddingofaunity-likelanguage.weusednuprl'stacticmechanism eort,soagooddealofworkwasdonewithoutitsbenet. OnemightaskwhynotjustuseHOL(forexample)?Theansweristhatwe Tacticsupport.Werepresenttheprotocolanditsspecicationusingafamiliar areaimingtomakenuprlaneectivetoolforawiderangeofformalproblems relatedtoprotocolverication.forexample,wewanttobeabletoreasonabout expressivepowercanbeagreatadvantage.ofcourse,thereareverication abstractionandrenementmethods(see[1]foranexample),anareawhere restrictionsthataecttherstkind. tasks,suchascheckingthattheatomicstatetransitionsofasystempreservea eectivenessofbasicinferencemechanisms,suchastermrewriting,iscrucial. property,whereexpressivepowermaybelessimportantandwherethespeedand applicationforthisfactinthisparticularcase,itisnoteworthythatconstructivityhasnotgottenintheway.itmaybepossibletoengineerconstructiveproofs simulationsoftheprotocolandproduceinterestingdataaboutthecurrentstate. ofprotocolsfromwhichonecansynthesize,forexample,programsthattrack Ourproofiscompletelyconstructive(bychoice).Whilewedon'tseemuch Onegoalofourworkistoenhancethesecondkindofreasoningwithoutimposing 2

3 paper.detailsofthecompletedformalizationwillbeavailableonthewebat completion.adescriptionofwhatremainstobedoneisincludedlaterinthe provementswemadetonuprl.theproofisnotyetnished,thoughitisnearing IntherestofthepaperwedescribetheSCIcorrectnessproofandtheim- ThissectiongivesanoverviewoftheSCIcachecoherenceprotocolanditsformalizationinNuprl.Beforeproceedingtotheoverview,wegiveabriefdescription ofnuprl.formalmathematicsinnuprlisorganizedinasinglelibrary,whichis displayforms,theorems,commentsorobjectscontainingmlcode.denitions termsandpreviouslydenedoperators.displayformsprovidenotationsforde- brokenintolessimulatingatheorystructure.libraryobjectscanbedenitions, 2SCICacheCoherenceanditsFormalizationinNuprl usesstructureeditors.theoremshavetreestructuredproofs,possiblyincomplete.eachnodehasasequent,andrepresentsaninferencestep.thestepis nedandprimitiveoperators.thesenotationsneednotbeparsablesincenuprl derivedfromthatoflcf,asishol's. someexampletypes:n2n:bn!bn, justiedeitherbyaprimitiverule,orbyatactic.nuprl'snotionoftacticis denenewoperators,possiblywithbindingstructure,intermsofexistingnuprl fx2nlistjx6=nilg;n2n:bn;(x;y):zn+==(x1y2=y1x2): Nuprl'stypetheoryhasarichsetoftypeconstructors.Thefollowingare numbersrepresentedaspairsofintegerswiththeusualequivalencerelation. ann-arybit-vectortoann-arybit-vector.thesecondisthetypeofnonempty Therstofthesecanbethoughtofasthetypeoffunctionsmappingannand isann-arybit-vector,andthelastisaquotienttyperepresentingtherational listofnaturalnumbers,thethirdisthecollectionofpairs(n;b)suchthatb 2.1SCICacheCoherence thatprotocol.adetaileddescriptionofourmodelcanbefoundin[3]. presentaveryhigh-leveldescriptionofourmodelofthecachecoherencepartof multiprocessorsinasharedmemorymodel[8].duetothespacelimitationswe TheSCIprotocolisanIEEEstandardforspecifyingcommunicationbetween trackof,forinstance,itsviewofthecache(cvp),knowledgeofwhetherornotits forthelinkedlist.insteadeachprocessorphasasetoflocalvariableswhichkeeps arise.theprotocolisdistributed;thereisnoglobalcacheorglobaldatastructure canbethoughtofasprioritizingprocessorssothatreadandwriteconictsdonot Processorswhichtrytoaccessthestoreformadoublylinkedlist.Thislist thelinkedlist,ifany.allcommunicationisviapoint-to-pointmessagepassing. Sinceaverylargenumberofprocessorscouldbeonthenetwork,ahugeamount viewisvalid(csp),anditscurrentsuccessor(succp)andpredecessor(predp)on 3

4 formalizingprovesthecorrectnessforanarbitrarynitenumberofprocessors.) IEEEstandardspeciesanupperboundof64,000processors.Theproofweare ofconcurrencyispresent,complicatingtheunderstandingoftheprotocol.(the lowingisanactionexecutedbythememorycontrollerm. Theprotocolisspeciedasasetofguardedactions.Forexample,thefol- buf[m]?readcachefreshq(p)! ifstatusm=gonethenbuf[p]!readcachefreshr(m;headm;cvm;gone) Here,theguardindicatesthatthisactioncanbeexecutediftherstmessage elsebuf[p]!readcachefreshr(m;headm;cvm;ok); inbuf[m](m'smessagebuer)hastypereadcachefreshqwhichindicatesthat headm:=p;ifstatusm=homethenstatusm:=fresh senttop.(argumentokindicatesthatnoprocessorsareonthelistwhichhave toprocessorp,ifsomeprocessoronthelisthadissuedawritequery(indicatedby theargumentgone).otherwise,responsereadcachefreshr(m;headm;cvm;ok)is processorpwantstoread.themessageisremovedfromthequeue(received)and requestedtomodifythestore.)localvariablestatusmisusedbymtorecord thebodyisexecuted.amessagereadcachefreshr(m;headm;cvm;gone)issent whethersomeprocessorisonthelistwhichhasissuedawritequery itsvalue isthengone;orwhetherprocessorsonthelisthaveissuedreadqueriesonly bebooleanconditions. containassignments,conditionals,andsends.inadditiontoreceives,guardscan itsvalueisthenfresh;orifnosuchquerieshavebeenissuedandhencethelist bymtorecordtheheadofthelist.asshownbythisexample,bodiescan isempty itsvalueisthenhome.finally,localvariableheadmismaintained aboveand17foreachprocessor.communicationisvia14typesofmessages, processorthatisalreadyonthedoublylinkedlistbecauseitisreading,andone madeupof7pairsofquery(q)andresponse(r)messages.inadditiontothe aboveaction,memoryhastwoactionsrespondingtowriterequests,onefroma Theprotocolisrepresentedas21actions:4formemoryincludingtheone fromaprocessorthatisnotyetonthelist.italsohasanactionrespondingtoa processorthatwantstogoothelist.the17actionsforeachprocessorinclude onereadrequest,twowriterequests,actionsforrequestingtogoonthelistor togoothelist(forexample,afterithas\accessed"thestore),anactionfor Severalroundsofmessagesmustbeexchangedbeforeaprocessorisonthelist Thishighdegreeofcommunicationisamaincomplicatingfactorintheprotocol. aswellasactionsthatrespondtoeachkindofrequestfromanotherprocessor. anddecidedthatitisindeedgoingtodoso,actionsformodifyingthecache, purgingothersothelistwhenithasbeengivenpermissiontowritethestore modiedandconstitutesanabstractionofthestructurewhicharisesduringan actualcomputation.avariablestatuspkeepstrackofaprocessorp'sstatewith respecttothelistandcantakeononeof8possiblevalues. withsuccpandpredpproperlyset.thus,thedoublylinkedlistisconstantly 4

5 2.2FormalizationinNuprl Ourformalizationofcorrectnessfollowscloselytheproofin[3].Ourembedding Wedeneastateasapairwheretherstcomponentistheusualmappingfrom ofthesemanticsofstatetransitionsystemsinnuprlisfairlystraightforward. identierstovalues.thesecondcomponentisahistoryvariablethatrecords dardnuprllibraries. execution.thishistoryvariableisimportantforreasoningabouttheprogram's givenbelow.booleans(b),atoms,integers(z),andlistsaredenedinthestan- thesequenceofmessagesthathavebeensentandreceivedduringtheentire PId=={k:Z k0} communicationbehavior.thenuprldenitionsofthecomponentsofstateare Forsimplicity,thevaluesofallidentiers(id)areassumedtobeintegers.The id==atompid mesg==zzlist state==(id!z)hist hist_el==bpidzmesg rstcomponentofanidentierisitsname(typeatom)andthesecondisthe ==hist_ellist processidentier(typepid)towhichthevariablebelongs.therstcomponent encodesthearguments. encodedasintegersastherstcomponentofamessage.thesecondcomponent ofahistoryelement(hist_el)isabooleanvalueindicatingwhetherthemessage isasend(tt)orareceive(ff).theremainingcomponentsarethesender, receiver,andmessage(typemesg).messagetypessuchasreadcachefreshqare x:=e==s.<y.if(x=y)then(es)else(ys),s.h> com==state!state wegivethedenitionoftheassignmentcommand. Expressionsandcommandsaredenedasfunctionsonstate.Asanexample, uationdenedas(es)and(ys)mapsidentierstovaluesandisdenedas Nuprl'sdisplayformsareusedtodene:=andasinxoperators.Thedot rstcomponentofthestate.thesendcommandupdatesthesecondcomponent commandsaredenedsimilarly.notethattheassignmentstatementupdatesthe (s.1y)(where.1denotestheprojectionoftherstelementofapair).other isusedforevaluationinastateandisoverloaded.hereesisexpressionevalementtothefrontofthehistory,butismorecomplicatedbecauseitcomputes thiselementfromthecontentsofthecurrenthistoryh.itusesanoperation arerepresentedinreverseorder.)thereceivecommandalsoaddsahistoryel- componentandthenewmessageasitslastcomponent.(historiesandbuers bysimplyaddingahistoryelementtothefrontofthehistorywithttasitsrst queue(p;h)whichltersoutthosehistoryelementsthatcontainmessagesthat projectedout. Inthiscase,themessagecomponentsoftheelementsoflistqueue(p;s.2)are havebeensentandnotyetreceivedbyprocessp.itthenchoosesthelast(oldest) ofaprocesspinstates,denoted(buf[p])s,isalsocomputedusingqueue. elementandcreatesanewcopywhoserstcomponentisff.themessagebuer conditionwhichisapredicateonstate(oftypestate!p1wherep1isthe Aprogramisdenedasapaircontainingalistofcommandsandaninitial 5

6 typeofnuprlpropositions).inourmodel,acommandisenabledifitchangesthe statewhenapplied.thuscommandswhoseguardsaretruebutdonotchange thestateareconsidereddisabled.atraceisdenedintheusualwayasafunction fromnaturalnumberstostatessuchthatforanyn,thereisanaction(enabled ornot)suchthatwhenappliedtostatenresultsinstaten+1. cache,thenmemoryistheowner.otherwise,theownerroughlycorrespondsto distributednatureoftheprotocol.ifnoprocessorhasrequestedtowritetothe temporallogicformulas.therst,forexample,expressesthatthereisalwaysa uniquecacheowner.thenotionofcacheownerisfairlycomplexbecauseofthe ThecorrectnessoftheSCIcachecoherenceprotocolisstatedasvelinear Inordertoshowthatthisuniquenesspropertyandtheotherfourproperties theprocessorpwhosevariablecsphasvaluedirty.however,therearevarious hold,weproveaseriesofcomplexinvariantsfromwhichthesepropertiesfollow. todirtyortosomethingelsemakingitorsomeotherprocessortheuniqueowner. alwaysamessageinsomeprocessor'sbuerthatwillcauseittosetitsvalueofcsp caseswhere0ormorethan1processorhasthisvalue.insuchcasesthereisa Theseinvariantsareexpressedas14lemmas(spanningseveralpagesin[3]), eachwithseveralinterdependentclauses.therearealsomanyauxiliaryconcepts thatappearintheinvariants.forexample,thereare6predicatesonprocessors indicatingtheirdegreeofprogressingettingonorothedoublylinkedlist.the mostcomplexconceptisafunctioncalledrankwhosevaluereectshowclosea processistogettingpermissiontowrite. smallerexample.themodeltheyusedwasextractedfromtheccodedescribing employsexplicitstateenumeration,toanalyzescicachecoherence.theirlargest oneaddressandtwodatavalues,andtheyreportedndingseveralerrorsusinga exampleincludedthreeprocessorswithonecachelineeach,onememorywith Inrelatedwork,SternandDill[11]useMur,avericationsystemthat theprotocolin[8],whereasourmodelhasbeenconstructedfromtheinformal Englishexplanation.Byabstractingatthislevel,inconsistenciesinthelowerleveldescriptionwereremoved.Ourmodelalsodiersfromtheirs(andfrom thesciprotocolstandard)inthatwehaveassumedthatmessagessentfrom cache.theotherisessentiallythesameasaninvariantinoneofoursupporting anddillcheckforcertainsafetyproperties,twoofwhichareformulatedas propertiesstatingthatprocessorsinacertainstatehaveaconsistentviewofthe invariants.oneoftheirinvariantscorrespondstooneofourvecorrectness oneprocessortoanotherprocessorarealwaysreceivedintheordersent.stern lemmasstatingatwhatpointaprocessorisattheheadofthelinkedlist. notbeapplicabletosci. seemssimpler,andalsoitseemsthattheabstractionmethodtheyemploymay BecausetheprotocolusesdirectoriesinsteadofthedistributedlistofSCI,it In[10],ParkandDillusePVStoverifytheFLASHcachecoherenceprotocol. 6

7 marizehowitwasusedinourproof. 3ImportedMathematics InthissectionwedescribetheconnectionbetweenHOLandNuprl,andsum- 3.1TheImportationMechanism sharable,includingtheoriesofbasicdatatypes,andalsoagooddealofthe Webelievethatmuchofthemathematicsusedinpracticalvericationishighly level.anholtheoryconsistsofsometypeandindividualconstants,some mathematicsrelatedtosoftwaremodelingandsemanticconnectionstoexternal tools.wehavetakenarststeptowardthiskindofsharingbyborrowingsome axioms(usuallydenitional)constrainingtheconstants,andasetoftheorems ofthemathematicsweneededforourvericationfromhol. theory,oneinterpretsthetypeconstantswithnuprltypesandthetermconstants followingfromtheaxioms(andtheaxiomsofancestortheories).toimporta ImportationofmathematicsfromHOLintoNuprlisdoneatthetheory isdone,thetheoremscanthenallbeacceptedimmediatelyasnuprltheorems. mustbeprovenexplicitly. withmembersoftheappropriatetypes,andthenprovestheaxioms.whenthis TypecheckingisundecidableinNuprl,sothewell-typednessofinterpretingterms mathematics,consideranexamplefromlisttheory.thefollowingisarawimportofaholtheoremstatingthatanon-emptylistisacons.becausenuprl erquantiesoverthetypesofall(small)non-emptytypes(thisquantieris currentlyhasasingleatnamespace,thenamesofallimportedconstantshave an\h"prependedtoavoidconictswithnuprlobjects.theoutermostquanti- 8'a:S"(hall(l:hlist('a). theoremsintothedesiredformispossible,andislargelyautomatable. uselessfordirectapplicationinnuprlproofs.itturnsoutthatmassagingthe Toillustratewhatkindoftransformationsareneededondirectlyimported TheoremsdirectlyimportedfromHOLareusuallyofaformthatmakesthem implicitinhol). portedconstants.thetransformed,\nuprl-friendly"theoremgeneratedfrom Apartfromtheoutermostquantier,thelogicalconnectivesthemselvesareim- himplies(hnot(hnulll)) theaboveis (hequal(hcons(hhdl)(htll))l))) theseconnectivesusebooleanlogicdenedwithinnuprl.thebooleanconnectivesarerewritteninthesecondtheoremtonuprl'snormallogicalconnectives, whicharedenedusingapropositions-as-typescorrespondence.theoperator ThelogicalconnectivesinHOLareallboolean-valuedfunctions,possiblytaking functionalarguments,asinthecaseofthequantiers.theinterpretationsof 8'a:S.8l:'aList.:mt(l))hd(l)::tl(l)=l. 7

8 importedlisttypeisinterpretedasnuprl'slisttype,andtheimportedtailfunctionisinterpretedasnuprl'stailfunction.notehoweverthathtlisapplied,asa "intheimportedtheoremcoercesabooleanintoanuprlproposition.the function,toitsargument,whilethenuprltlisadenedoperatorwithasingle importedtheorem.eachoftheimportedconstantsinthetheoremactuallyhas operand(nuprlalsohasanoperatorforfunctionapplication,ofcourse).we atleastonetypeargument.intherewrittentheorem,therearenohiddentype arguments(thenuprloperationsare\implicitlypolymorphic"). haveusedanotationaldevicetosuppresstypeargumentsinthe(pre-rewrite) list.inhol,thisisatotalfunctiononlists.whenweimportitintonuprl, not.sincehhdispolymorphic,givenanarbitrarytypeandtheemptylistasan argument,itmustchoosesomearbitrarymemberofthetypeasoutput.thus wemustprovethattheinterpretationreturnsavalueoneverylist,emptyor Themostinterestingpointinthistranslationisthefunctionforheadofa wemustgivehhdanoncomputabledenitioninnuprl.however,wecanprove givesusaconditionalrewritewhichgoesthroughforthisexampletheorem. 3.2HOLMathUsedintheSCIVerication thatthisfunctionisthesameasnuprl'shdwhenthelistisnon-empty.this oftheoremsaboutlists.listsareimportantintwocentralareasoftheproof. sophisticatedlistmanipulationsince,asmentioned,theyarecomputedfromthe ThemainsourceofHOLtheoremsusedintheSCIvericationisalargebody First,thedenitionandproofofpropertiesaboutthecontentsofbuersrequire thatbut_last_el((buf[p])s)isthecontentsofp'sbuerafterpreceivesa itsbuerbecomesm::((buf[p])s)where::istheconsoperator.theproof isstraightforwardtoprovethatwhenamessagemissenttoprocesspinstates, messageissignicantlymorecomplex.theoperatorbut_last_elisdenedin historycomponentofastate.forexample,fromthedenitionofbuer,itfairly anhollibraryintermsofthelastnoperator(theoperationwhichextractsthe reasoningabouttheseoperators.theexistingholtheoremsabouttheseanda lastnelementsofalist)whichisalsodenedinhol.thesnocoperator,which useofthismachineryisessentialforalargeproofsuchasthesciverication. providespowerfulautomationfortheapplicationofrewritelemmasandgood varietyofotheroperatorsweredirectlyusableinthisandotherproofs. historiesandbuers.avarietyofothertheoremsabouthistoriesandbuers Weprovedandmakeextensiveuseofnumerousotherrewritelemmasinvolving Theabovetwotheoremsareexamplesoflemmasusedasrewriterules.Nuprl havealsobeenprovedandusedassupportforotherkindsofrewritelemmas. q'sbuer,orthereis0or1rmessagesinp'sbuer,butnotboth.ourrewrite QmessageforwhichaprocessoriswaitingforthecorrespondingRmessage. Thismeansthatthereiseither0or1Qmessagesfromaprocessorpinsome oneoutstandingmessage.inparticular,foranyq/rpair,thereisatmostone Oneinvariant(partofLemma9[3])statesthatanyprocessorhasatmost 8

9 notionofrank.rankroughlycorrespondstotheorderinwhichprocessorshave lemmasalongwithvariousotherlistoperatorsandpropertiesfromholplaya requestedtoreadorwritetothecache.itisonlydenedforactiveprocessors, centralroleinprovingthisfact. importantpropertyisthefactthatforanyprocessor,itsrankdoesnotincrease. apropertyofprocessorsthatareonor\mostlyon"thedoublylinkedlist.an Thesecondareaoftheproofinwhichlistsareimportantisindeningthe Thispropertyinsuresthatthelistdoesnotcontaincircularities.Aslongasa eachactiveprocessorintheresultinglist.therstoccurrencecorrespondstoa processstaysactive(andafewotherpropertieshold)itsrankwilldecreaseuntil processor'smostrecentrequest.weproveavarietyoflemmasdescribinghowa hasreceived,projectingoutthesender,andkeepingonlytherstoccurrenceof isdenedbylteringfromthehistoryallreadandwriterequeststhatmemory itbecomes0atwhichpointitisallowedtowriteifithasrequestedtodoso.rank 4ATypeAnnotationSchemeforNuprl processor'srankchangeswithchangesinthestate.theselemmasarealsoused asrewriterulesinprovinginvariants. meetsthefollowinggoals. Ourtypeannotationschemeisawayofattachingtypeexpressions,whichwe callannotations,toall(oronlysome)ofthesubtermsofaterm.ourscheme 2.IfatermtisintroducedintoaproofasamemberofatypeT,andtoccurssomewhereinthecurrentgoalwithacompatibleannotation,thenthe themaretreatedasbeforebynuprl'stactics. 1.Annotationsareoptional.Termsthatdonothaveannotationsattachedto requirementtoprovet2tiseliminated. 4.Therearenoheuristicsintheschemeperse.Althoughtypeinferenceand 3.Annotationsjustifyrewriting,sothatasubtermwithanannotationAcanbe checkingarehighlyheuristicinnuprl,thisisindependentoftheannotation scheme.annotationsfortermsaregeneratedbyexaminingtheresultsof replacedbyanequalterm(quamemberofa)withoutfurtherjustication. 5.Annotationscanbeeectivelymaintained.Inprincipal,itispossiblefor intheinductionruleneedstoreannotated(orleftwithoutannotations). annotationstobelostduringinference.forexample,thegeneralizedterm applyingnuprl'sexistingmachinery. 6.Therearenoglobaltables.Weretainthetree-structuringofproofs,with annotationsarealmostneverlostduringequationalrewriting. However,suchinferencestepsformatinyfractioninpractice.Forexample, 7.Soundnessdependsonlyonaxedsetofprimitiveinferencerulesthatall dependency-directedbacktracking,andselectivereplayofsubproofs. proofsmustreduceto. independenceofproofbranches,thatallowsus,amongotherthings,todo 8.Theschemeisalmostentirelyinvisibletousers. 9

10 PVSusesatypingdisciplinethatachievesmostofthegoalsabove,butitwould assubtypes,(alimitedformof)dependenttypes,andundecidabletypechecking. onlybeapplicabletoaninsucientlysmallsubtheoryofnuprl.somecomplicatingaspectsofnuprl,whicharen'tpresentinpvs,are:universepolymorphism; ThetypetheoryofthePVSsystem[9]hassomesimilaritiestoNuprl,such isenlargedwhenitsdomainisshrunk;andgeneraldependenttypes.inaddition, thepvsschemedoesnotaddress7above. inonetypeandnotintheother;contravariantsubtyping,whereafunctiontype type-indexedequality,sothattwotermsmaybothbeintwotypes,butbeequal theform notypesareassociatedwiththevariablesinthissyntax.anannotatedtermhas eachoperandxi:ei,eachofthevariablesinthesequencexibindsinei.notethat Nuprltermshavetheform(x1:e1;:::;xn:en)whereisanoperatorandin notationsoftheterm,andcanbethoughtofastheexpectedtypesforthe operands,andbistheannotationtypeoftheterm.informally,ei:[i]aican wheretheeiarealsoannotatedterms.theexpressions[i]aiarethesuban- (:::;xi:ei:[i]ai;:::):b refertothevariablesinxi,andcancontain,forexample,assertionsoftheform bethoughtofasmeaningthatunderassumptioni,eihastypeai.theican x2t.examplesofannotatedtermsarefact((3:z):[true]n):n,wherefact, NandZarefactorial,thenaturalnumbersandtheintegersrespectively,and if(b:b;e1:[b]a;e2:[:b]a):a. wheretheoperande:aisitselfanannotatedterm,werequire,rst,thatfor subannotationsandtothesubannotationsofanimmediatelysurroundingterm. andsowerequireonlyrespectforequality.forexample,in((e:a):[]a0):b; Wechosetheminimalrequirementthatsupportsrewritingasdescribedabove, Oneofthekeypointsishowtheannotationtypeofatermrelatestoits presenceofbindingvariablesisstraightforward. ifx=e2athenx=e2a0.thegeneralizationofthisrequirementtothe allx2a0,ifx=e2a0then(x)=(e)2b,and,second,thatforallx2a, undecidable,andmustbeproven.onepossibilitywouldbetogenerate\type byputtingtogetherappropriateprimitiveinferencerules,andneedanopportunitytoassembleproofsofannotationvalidityatthesametimeastheproofs checkingconditions"aspvsdoes,whicharesideconditionsgeneratedwhenever anewtermisintroduced.thisisnotworkablefornuprlbecausetacticswork AswithordinarytypinginNuprl,thevalidityofanannotationofatermis terms,itisnaturaltomodifyrewritingtotakeanannotatedterm,andproduce arecorrect.wethereforehavetwokindsofannotations:onekindwecanassume anewterm,anequalityproof,andalsoaproofthatthenewterm'sannotations andproducingarewrittentermalongwithaproofofequality.forannotated justifyingthemaininference.rewritingworks,forexample,bytakingaterm ofthesemanticsofsequents.afullreportisinpreparation. arevalidduringthecourseofaproof,andtheothermustbeprovedtobevalid. Theannotationschemeisjustiedsemantically,andrequiresare-interpretation 10

11 Thedenitionbelowencodestheformula2Pfromlineartemporallogicand 5TheCorrectnessProofinNuprl iscentralinprovinginvariants.astatesisinanexecutionofprogramprg, inv(prg;s.i[s])==8s:state.in_exec(prg;s))i[s] Inaproofofthismagnitude,itwasessentialtoprovideahighdegreeofautomation.Ourautomationfallsroughlyintotwocategories:tacticsthatdecompose Boththedecompositionpropertiesandrewritetheoremsincludegeneraltheo- reasoningmodularly,andpropertiesexpressingequalityandequivalencethatcan beusedbynuprl'srewritingmachinerysuchasthosementionedinsect.3.2. remsandtheoremsspecictosci.therewritesformessagebuersdiscussedin Sect.3.2,forexample,arenotspecictoSCI,whilethenotionofrankis.The decompositiontacticsrelyonlemmasthatwehaveproven,suchasonestating eachactionoftheprogramandtoshowthattheinitialconditionholdsinthe whichdecomposereasoninginto21cases,oneforeachmemoryactionandone initialstate.fromthisgenerallemma,weproveddecompositionlemmasforsci thattoshowthatinv(prg;s.i[s])holds,itsucestoconsideronecasefor denotedin_exec(s;prg),ifsoccursinsometraceofprg. receive,andassignmentstatements.rewritingoperatesonthesesimpliedcases. generationoftheirstatements aswellasavarietyofotherpropertiesspecic composeconditionalstatementsintocasessothateachcasecontainsonlysend, AlthoughthesedecompositionpropertiesarespecictoSCI,weautomatedthe foreachprocessoractionforsomearbitraryprocessorp.wechosetofurtherde- tosci fromthedenitionsoftheactions.theirproofswereoftenlargely automaticalso.wealsoautomatedtheapplicationofmanyoftheselemmasby writingtacticswhichapplythemandsolvevarioussubgoalsautomatically. arefairlysimpleandexpresspropertiesaboutthevaluesthatvariousvariables cantakeonduringexecution.forexample,weprove: Ofthe14lemmasexpressinginvariants,therst8(roughly2.5pagesin[3]) HereP(n)denotesthesetofprocessorsinvolvedintheprotocol,withprocess identiers1;:::;n. readcachefreshr(p;r;cv;arg)2buf[p]) The9thlemmacontainsvestatementswhichtogetherexpresstheproperty [p=m^q2p(n)^(r=nil_r2p(n))^(arg=ok_arg=gone)]: ofoutstandingmessagesdescribedinsect.3.2aswellaseightstatementsexpressingwhichkindofoutstandingmessageaprocessorphasdependingonthe valueofstatusp.lemmas10and11expressavarietyofpropertiesoftheform proofssimilartothosefortheotherinvariants.lemma12expressessomebasic 2(PWQ)(whereWistheweakuntiloperator).Weprovedageneraldecompositiontheoremforformulasofthisformwhichmakesthestructureofthese mustbeprovenasinvariants.whiletheinvariantsuptothispointarelarge anddetailed,theyarefairlystraightforwardtoprove.themaindicultyinthe (whichisslightlydierentbutequivalenttotheonegivenin[3])andtwowhich propertiesaboutrankincludingtwowhichfollowdirectlyfromthedenition 11

12 proofisfoundinthe13thand14thlemmas.lemma13has17clausesandone protocol. thecomplexinvariantsaboutrankthatarerequiredtoprovecorrectnessofthe assumptionwhichlatergetsdischargedandlemma14has7clauses.theystate example,wehaveproventheinvariant: thetwopropertiesoflemma12thatfollowfromthedenitionofrank.wehave alsoproven5andnearlycompleted2moreofthe17clausesoflemma13.for TheproofsupthroughandincludingLemma11arecompleted,aswellas velopedalloftherewritelemmasabouttherankfunctionandallotherauxilliary wherevisitingprocessorsareasubsetoftheactiveones.indoingso,wehavede- predicatesthatweneedtocompletetheremainderoflemmas12,13,and14. purgeq(q)2buf[p])(visiting(p)^rank(q)=rank(p)+1) propertiesfollowfromtheseinvariantswillbedetailedbutstraightforward. Thereasoningneededtocompletetheproofbyshowingthatthedesiredsafety wehadtoaddandprovesomeadditionalclauses.oneisaninvariantexplicitly assertionswehadformulated,althoughtheyaretrue.toprovetheseconjuncts, errorsintheprotocol.however,wehavefoundtwoerrorsintheproof.twoof theconjunctsoftherstclauseoflemma13couldnotbeprovedusingthe Becausewestartedfromaproofofcorrectness[3],wedidnotexpecttond statingthattwoparticularmessagessentfromoneprocessortoanotherare receivedintheordersent. References 1.C.-T.ChouandD.Peled.Verifyingamodel-checkingalgorithm.InToolsand 2.R.L.Constable,etal.ImplementingMathematicswiththeNuprlProofDevelopmentSystem.Prentice-Hall,EnglewoodClis,NewJersey,1986. NotesinComputerScience,pages241{257.Springer-Verlag,1996. AlgorithmsfortheConstructionandAnalysisofSystems,volume1055ofLecture 4.A.P.FeltyandD.J.Howe.HybridinteractivetheoremprovingusingNuprland 3.A.FeltyandF.Stomp.Acorrectnessproofofacachecoherenceprotocol ceedingsofthe11thannualconferenceoncomputerassurance,1996. Availableatwww.cs.bell-labs.com/felty/sci/.AnearlierversionappearsinPro- 5.M.J.C.GordonandT.F.Melham.IntroductiontoHOL:ATheoremProving 6.D.J.Howe.Oncomputationalopen-endednessinMartin-Lof'stypetheory.In EnvironmentforHigherOrderLogic.CambridgeUniversityPress, ofLectureNotesinComputerScience,pages351{365.Springer-Verlag,1997. HOL.InFourteenthInternationalConferenceonAutomatedDeduction,volume 7.D.J.Howe.ImportingmathematicsfromHOLintoNuprl.InTheoremProving ProceedingsoftheSixthAnnualSymposiumonLogicinComputerScience,pages 8.IEEE-P Nov90-doc197-iii.PartIIIA:SCICoherenceOverview,1990.UnapprovedDraft.ApprovedstandardisdescribedinIEEEStd \The 267{281.Springer-Verlag, {172.IEEEComputerSociety,1991. ScalableCoherentInterface". inhigherorderlogics,volume1125oflecturenotesincomputerscience,pages 12

13 10.S.ParkandD.L.Dill.VericationofFLASHcachecoherenceprotocolbyaggregationofdistributedtransactions.In8thACMSymposiumonParallelAlgorithms InCorrectHardwareDesignandVericationMethods,1995. AspectsofComputerSoftware,volume1281ofLectureNotesinComputerScience. 9.S.OwreandN.Shankar.TheformalsemanticsofPVS.Technicalreport,SRI, 11.U.SternandD.L.Dill.AutomaticvericationoftheSCIcachecoherenceprotocol. August B.Werner.Setsintypes,typesinsets.InInternationalSymposiumonTheoretical andarchitectures,1996. Springer-Verlag,

Reprintofapaperpresentedatthe8thACMSymposiumonOperatingSystem Principles,PacicGrove,California,14{16December1981.(ACMOperating DesignandVericationofSecureSystems SystemsReviewVol.15No.5pp.12-21) ComputerScienceLaboratory

More information

FromDependableComputingforCriticalApplications{5,Champaign,IL,September1995,pp.139{157;Volume10of theseriesindependablecomputingandfaulttolerantsystemspublishedbyieeecomputersocietypress. ByzantineAgreementwithAuthentication:Observationsand

More information

Application. Generic Conference Control (T.124) Multipoint Communications Service (T.122/T.125) Network Specific Transport Protocols (T.

Application. Generic Conference Control (T.124) Multipoint Communications Service (T.122/T.125) Network Specific Transport Protocols (T. ATRANSPORT-INDEPENDENTCOMPONENTFORA GROUPANDSESSIONMANAGEMENTSERVICEIN GROUPCOMMUNICATIONSPLATFORMS ComputerEngineeringandNetworksLaboratory(TIK) ErikWilde,MuraliNanduri,BernhardPlattner SwissFederalInstituteofTechnology(ETHZurich)

More information

KeyEscrowinMutuallyMistrustingDomains?

KeyEscrowinMutuallyMistrustingDomains? KeyEscrowinMutuallyMistrustingDomains? Abstract.Inthispaperwepresentakeyescrowsystemwhichmeets L.Chen,D.GollmannandC.J.Mitchell possiblerequirementsforinternationalkeyescrow,wheredierentdomainsmaynottrusteachother.inthissystemmultiplethirdparties,

More information

timeout StoR!msg0 RtoS?ack0

timeout StoR!msg0 RtoS?ack0 c1997kluweracademicpublishers,boston.manufacturedinthenetherlands. FormalMethodsinSystemDesign,,?{??(1997) SymbolicVericationofCommunication ProtocolswithInniteStateSpacesusingQDDs queues.itiswell-knownthatmostinterestingvericationproblems,suchasdeadlockdetection,

More information

InclusionConstraintsover MartinMuller1,JoachimNiehren1andAndreasPodelski2 Non-emptySetsofTrees? UniversitatdesSaarlandes,66041Saarbrucken,Germany ImStadtwald,66123Saarbrucken,Germany 2Max-Planck-InstitutfurInformatik,

More information

1. What are the three types of business organizations? Define them

1. What are the three types of business organizations? Define them Written Exam Ticket 1 1. What is Finance? What do financial managers try to maximize, and what is their second objective? 2. How do you compare cash flows at different points in time? 3. Write the formulas

More information

Last not not Last Last Next! Next! Line Line Forms Forms Here Here Last In, First Out Last In, First Out not Last Next! Call stack: Worst line ever!

Last not not Last Last Next! Next! Line Line Forms Forms Here Here Last In, First Out Last In, First Out not Last Next! Call stack: Worst line ever! ECE 551 C++ Programming, Data structures, and Algorithms Abstract Data Type: Stack Last In First Out (LIFO) 1 2 2 1 4 3 1 3 4 Stacks in Programming Worst line ever! 5 3 1 5 Stacks are not useful for waiting

More information

AccountView. Single Sign-On Guide

AccountView. Single Sign-On Guide AccountView Single Sign-On Guide 2014 Morningstar. All Rights Reserved. AccountView Version: 1.4 Document Version: 2 Document Issue Date: March 09, 2013 Technical Support: (866) 856-4951 Telephone: (781)

More information

2Proofbymathematicalinductionplaysacrucialroleinthevericationofprogramtrans-

2Proofbymathematicalinductionplaysacrucialroleinthevericationofprogramtrans- SubmissiontoJ.FunctionalProgrammingSpecialIssueonTheoremProving&FunctionalProgramming AutomaticVericationofFunctionswith DepartmentofComputing&ElectricalEngineering, AccumulatingParameters UniversityofEdinburgh,80SouthBridge,

More information

Binary Heaps * * * * * * * / / \ / \ / \ / \ / \ * * * * * * * * * * * / / \ / \ / / \ / \ * * * * * * * * * *

Binary Heaps * * * * * * * / / \ / \ / \ / \ / \ * * * * * * * * * * * / / \ / \ / / \ / \ * * * * * * * * * * Binary Heaps A binary heap is another data structure. It implements a priority queue. Priority Queue has the following operations: isempty add (with priority) remove (highest priority) peek (at highest

More information

DATA STRUCTURE - STACK

DATA STRUCTURE - STACK DATA STRUCTURE - STACK http://www.tutorialspoint.com/data_structures_algorithms/stack_algorithm.htm Copyright tutorialspoint.com A stack is an abstract data type ADT, commonly used in most programming

More information

Data Structures and Algorithms Lists

Data Structures and Algorithms Lists Data Structures and Algorithms Lists Chris Brooks Department of Computer Science University of San Francisco Department of Computer Science University of San Francisco p.1/19 5-0: Abstract Data Types An

More information

W10 HOW TO TEST YOUR NEW.NET APPLICATIONS. Dan Koloski Empirix Software BIO PRESENTATION. May 19, 2004 1:45PM

W10 HOW TO TEST YOUR NEW.NET APPLICATIONS. Dan Koloski Empirix Software BIO PRESENTATION. May 19, 2004 1:45PM BIO PRESENTATION W10 May 19, 2004 1:45PM HOW TO TEST YOUR NEW.NET APPLICATIONS Dan Koloski Empirix Software International Conference On Software Testing Analysis and Review May 17-21, 2004 Orlando, Florida

More information

H.Bowman@ukc.ac.uk,G.Faconti@cnuce.cnr.itandM.Massink@guest.cnuce.cnr.it

H.Bowman@ukc.ac.uk,G.Faconti@cnuce.cnr.itandM.Massink@guest.cnuce.cnr.it 3Dept.ofComputerScience,U.ofYork,Heslington,York,YO15DD,UK SpecicationandVericationofMedia 1ComputingLab.,U.ofKent,Canterbury,Kent,CT27NF,UK HowardBowman1,GiorgioP.Faconti2andMiekeMassink3 2CNR-IstitutoCNUCE,ViaS.Maria36,56126-Pisa-Italy

More information

DATA STRUCTURE - QUEUE

DATA STRUCTURE - QUEUE DATA STRUCTURE - QUEUE http://www.tutorialspoint.com/data_structures_algorithms/dsa_queue.htm Copyright tutorialspoint.com Queue is an abstract data structure, somewhat similar to stack. In contrast to

More information

SERVICES PRICE LIST - COMMERCIAL Sysorex Government Services, Inc.

SERVICES PRICE LIST - COMMERCIAL Sysorex Government Services, Inc. SERVICES - COMMERCIAL Sysorex Government Services, Inc. ITEM NUMBER LABOR TYPE DESCRIPTION PT00201 PT00202 Junior System Staff System equivalent working knowledge of System ing $ 109.63 experience or equivalent,

More information

Sorting revisited. Build the binary search tree: O(n^2) Traverse the binary tree: O(n) Total: O(n^2) + O(n) = O(n^2)

Sorting revisited. Build the binary search tree: O(n^2) Traverse the binary tree: O(n) Total: O(n^2) + O(n) = O(n^2) Sorting revisited How did we use a binary search tree to sort an array of elements? Tree Sort Algorithm Given: An array of elements to sort 1. Build a binary search tree out of the elements 2. Traverse

More information

TESTING WITH JUNIT. Lab 3 : Testing

TESTING WITH JUNIT. Lab 3 : Testing TESTING WITH JUNIT Lab 3 : Testing Overview Testing with JUnit JUnit Basics Sample Test Case How To Write a Test Case Running Tests with JUnit JUnit plug-in for NetBeans Running Tests in NetBeans Testing

More information

Montgomery G.I. Bill Selected Reserve (Chapter 1606)

Montgomery G.I. Bill Selected Reserve (Chapter 1606) Montgomery G.I. Bill Selected Reserve (Chapter 1606) What is Chapter 1606 GI Bill? Montgomery G.I. Bill Selected Reserve (Chapter 1606) Monthly educational stipend for service members who are currently

More information

Abstract Data Type. EECS 281: Data Structures and Algorithms. The Foundation: Data Structures and Abstract Data Types

Abstract Data Type. EECS 281: Data Structures and Algorithms. The Foundation: Data Structures and Abstract Data Types EECS 281: Data Structures and Algorithms The Foundation: Data Structures and Abstract Data Types Computer science is the science of abstraction. Abstract Data Type Abstraction of a data structure on that

More information

3.Processstatemonitoring

3.Processstatemonitoring Chapter14 Processmonitoringandvisualisation O.SimulaandJ.Kangas HelsinkiUniversityofTechnology,LaboratoryofComputerandInformation usingself-organizingmaps Science,Rakentajanaukio2C,02150Espoo,Finland,Fax:358(0)4513277,

More information

fromformalvericationtoautomatictesting? ValidationofSynchronousReactiveSystems: fnicolas.halbwachs,pascal.raymondg@imag.fr NicolasHalbwachs,PascalRaymond thevalidationofreactivesystemsdescribedinthesynchronousdata-ow

More information

COSC 3351 Software Design. Architectural Design (II) Edgar Gabriel. Spring 2008. Virtual Machine

COSC 3351 Software Design. Architectural Design (II) Edgar Gabriel. Spring 2008. Virtual Machine COSC 3351 Software Design Architectural Design (II) Spring 2008 Virtual Machine A software system of virtual machine architecture usually consists of 4 components: Program component: stores the program

More information

Classes and Pointers: Some Peculiarities (cont d.)

Classes and Pointers: Some Peculiarities (cont d.) Classes and Pointers: Some Peculiarities (cont d.) Assignment operator Built-in assignment operators for classes with pointer member variables may lead to shallow copying of data FIGURE 3-22 Objects objectone

More information

SBM2302 Advanced Supply Chain Management 2

SBM2302 Advanced Supply Chain Management 2 SBM2302 Advanced Supply Chain Management 2 UOS CODE SBM2302 SUMMARY UOS NAME Advanced Supply Chain Management CREDIT POINTS 6 STATUS Elective Supply Chain Management (SCM) is strategically important and

More information

REQUEST FOR RE=iCORDS ITION AUTHORITY

REQUEST FOR RE=iCORDS ITION AUTHORITY REQUEST FOR RE=iCORDS ITION AUTHORITY JOB (See instructions on separate page) -/11 - ~ l/ / - tj/ - / J J To: NATIONAL ARCHIVES and RECORDS ADMINISTRATION W DC 20408 (NWM) /tj-;) 7-- 00 NOTIFICATION TO

More information

Get me off Your Fucking Mailing List

Get me off Your Fucking Mailing List Get me off Your Fucking Mailing List David Mazières and Eddie Kohler New York University University of California, Los Angeles http://www.mailavenger.org/ Abstract off off off mailing 1 Introduction off

More information

Electronic Circuits for Mechatronics ELCT609 Lecture 7: MOS-FET Transistor

Electronic Circuits for Mechatronics ELCT609 Lecture 7: MOS-FET Transistor Electronic Circuits for Mechatronics ELCT609 Lecture 7: MOS-FET Transistor Assistant Professor Office: C3.315 E-mail: eman.azab@guc.edu.eg 1 Introduction Why we call it Transistor? The name came as an

More information

A framework for distributed digital object services

A framework for distributed digital object services International Journal on Digital Libraries (2006) 6(2): 115 123 DOI 10.1007/s00799-005-0128-x REGULAR PAPER Robert Kahn Robert Wilensky A framework for distributed digital object services Published online:

More information

Online. 2011-2012: Implement in Spring 2012 2012-2013 2013-2014

Online. 2011-2012: Implement in Spring 2012 2012-2013 2013-2014 Major Program: CISS Graduate - Masters in Information Systems & Security Mission of the Department: The Department of Computer Information Systems & Security (CISS) is dedicated to providing students,

More information

Outline. Computer Science 331. Stack ADT. Definition of a Stack ADT. Stacks. Parenthesis Matching. Mike Jacobson

Outline. Computer Science 331. Stack ADT. Definition of a Stack ADT. Stacks. Parenthesis Matching. Mike Jacobson Outline Computer Science 1 Stacks Mike Jacobson Department of Computer Science University of Calgary Lecture #12 1 2 Applications Array-Based Linked List-Based 4 Additional Information Mike Jacobson (University

More information

AdvancedNetworkManagementFunctionalities throughtheuseofmobilesoftwareagents 1DipartimentodiMatematica,UniversitadiMessina C.daPapardo-SalitaSperone,98166Messina-Italy AntonioPuliato1,OrazioTomarchio2

More information

2015-10-22 19:22:59 Report Generated: 10/22/2015 20:03 UTC. CPU Intel Xeon E5-2670 v2 2.50GHz Connections 1 Mean Jitter 10/22/15 1

2015-10-22 19:22:59 Report Generated: 10/22/2015 20:03 UTC. CPU Intel Xeon E5-2670 v2 2.50GHz Connections 1 Mean Jitter 10/22/15 1 2015-10-22 19:22:59 Report Generated: 10/22/2015 20:03 UTC Page 1 of 10 Provider Amazon Web Services Test Protocol TCP Mean Bandwidth Service Amazon EC2 Direction Up Median Bandwidth Region us-west-2 Duration

More information

Admissions Protocol and Procedures

Admissions Protocol and Procedures Admissions Protocol and Procedures NewFriendsAdmissions WewelcomeinquiriesfromfamiliesinterestedinCamphillCommunitiesCalifornia. CamphillCommunitiesCaliforniaisanot7for7profit501(c)3organizationandispartof

More information

ENUM successes failures - alternatives. 18/4/2012 ENUM success, failures, alternatives 1

ENUM successes failures - alternatives. 18/4/2012 ENUM success, failures, alternatives 1 ENUM successes failures - alternatives 18/4/2012 ENUM success, failures, alternatives 1 ENUM ecosystem components 18/4/2012 Ändern über "Ansicht" / "Kopf- und Fusszeile" 2 ENUM ecosystem components II

More information

Measuring Universal Intelligence By: Tyler Staudinger

Measuring Universal Intelligence By: Tyler Staudinger [1] Measuring Universal Intelligence By: Tyler Staudinger Overview How Do we Define Intelligence? Current Tests of Machine Intelligence The Ideal Test for Intelligence Components of an Intelligence Test

More information

Data Management Plan Template Guidelines

Data Management Plan Template Guidelines Data Management Plan Template Guidelines This sample plan is provided to assist grant applicants in creating a data management plan, if required by the agency receiving the proposal. A data management

More information

Queues and Stacks. Atul Prakash Downey: Chapter 15 and 16

Queues and Stacks. Atul Prakash Downey: Chapter 15 and 16 Queues and Stacks Atul Prakash Downey: Chapter 15 and 16 Queues Queues occur in real life a lot. Queues at checkout Queues in banks In software systems: Queue of requests at a web servers Properties of

More information

Two-Level Metadata Management for Data Deduplication System

Two-Level Metadata Management for Data Deduplication System Two-Level Metadata Management for Data Deduplication System Jin San Kong 1, Min Ja Kim 2, Wan Yeon Lee 3.,Young Woong Ko 1 1 Dept. of Computer Engineering, Hallym University Chuncheon, Korea { kongjs,

More information

SysAid Remote Discovery Tool

SysAid Remote Discovery Tool SysAid Remote Discovery Tool SysAid Release 7 Document Updated: 27-Apr-10 SysAid Remote Discovery Tool The SysAid server comes with a built-in discovery service that performs various network discovery

More information

Performance Comparison of SCTP and TCP over Linux Platform

Performance Comparison of SCTP and TCP over Linux Platform Performance Comparison of SCTP and TCP over Linux Platform Jong-Shik Ha, Sang-Tae Kim, and Seok J. Koh Department of Computer Science, Kyungpook National University, Korea {mugal1, saintpaul1978, sjkoh}@cs.knu.ac.kr

More information

Situational Awareness at Internet Scale: Detection of Extremely Rare Crisis Periods

Situational Awareness at Internet Scale: Detection of Extremely Rare Crisis Periods Situational Awareness at Internet Scale: Detection of Extremely Rare Crisis Periods 2008 Sandia Workshop on Data Mining and Data Analysis David Cieslak, dcieslak@cse.nd.edu, http://www.nd.edu/~dcieslak/,

More information

1.04 1.02 0.98 0.96 0.94 0.92 0.9

1.04 1.02 0.98 0.96 0.94 0.92 0.9 ANewExtensionoftheKalmanFiltertoNonlinear SimonJ.JulierSystems TheRoboticsResearchGroup,DepartmentofEngineeringScience,TheUniversityofOxford Oxford,OX13PJ,UK,Phone:+44-1865-282180,Fax:+44-1865-273908 siju@robots.ox.ac.ukuhlmann@robots.ox.ac.uk

More information

ISO/IEC 9126 in practice: what do we need to know?

ISO/IEC 9126 in practice: what do we need to know? ISO/IEC 9126 in practice: what do we need to know? P. Botella, X. Burgués, J.P. Carvallo, X. Franch, G. Grau, J. Marco, C. Quer Abstract ISO/IEC 9126 is currently one of the most widespread quality standards.

More information

Smart Integration of Wireless Temperature Monitoring System with Building Automation System

Smart Integration of Wireless Temperature Monitoring System with Building Automation System Smart Integration of Wireless Temperature Monitoring System with Building Automation System Case Study Area of engagement Solution to integrate wireless temperature monitoring system with BMS (Building

More information

Appendix B Checklist for the Empirical Cycle

Appendix B Checklist for the Empirical Cycle Appendix B Checklist for the Empirical Cycle This checklist can be used to design your research, write a report about it (internal report, published paper, or thesis), and read a research report written

More information

Quality of Service Routing Network and Performance Evaluation*

Quality of Service Routing Network and Performance Evaluation* Quality of Service Routing Network and Performance Evaluation* Shen Lin, Cui Yong, Xu Ming-wei, and Xu Ke Department of Computer Science, Tsinghua University, Beijing, P.R.China, 100084 {shenlin, cy, xmw,

More information

Recursion. Definition: o A procedure or function that calls itself, directly or indirectly, is said to be recursive.

Recursion. Definition: o A procedure or function that calls itself, directly or indirectly, is said to be recursive. Recursion Definition: o A procedure or function that calls itself, directly or indirectly, is said to be recursive. Why recursion? o For many problems, the recursion solution is more natural than the alternative

More information

AUTOMATIC PROTOCOL CREATION FOR INFORMATION SECURITY SYSTEM

AUTOMATIC PROTOCOL CREATION FOR INFORMATION SECURITY SYSTEM AUTOMATIC PROTOCOL CREATION FOR INFORMATION SECURITY SYSTEM Mr. Arjun Kumar arjunsingh@abes.ac.in ABES Engineering College, Ghaziabad Master of Computer Application ABSTRACT Now a days, security is very

More information

Computer Science 483/580 Concurrent Programming Midterm Exam February 23, 2009

Computer Science 483/580 Concurrent Programming Midterm Exam February 23, 2009 Computer Science 483/580 Concurrent Programming Midterm Exam February 23, 2009 Your name There are 6 pages to this exam printed front and back. Please make sure that you have all the pages now. The exam

More information

TIBCO ActiveMatrix BPM Integration with Content Management Systems Software Release 2.2.0 September 2013

TIBCO ActiveMatrix BPM Integration with Content Management Systems Software Release 2.2.0 September 2013 TIBCO ActiveMatrix BPM Integration with Content Management Systems Software Release 2.2.0 September 2013 Two-Second Advantage Important Information SOME TIBCO SOFTWARE EMBEDS OR BUNDLES OTHER TIBCO SOFTWARE.

More information

FSPAMFPI06 Complete reports for mortgage and/or financial planning clients

FSPAMFPI06 Complete reports for mortgage and/or financial planning clients Complete reports for mortgage and/or financial planning clients Overview You must be able to accurately complete reports of a complex nature, and take a proactive approach to the preparation of valuations

More information

Identity based Authentication in Session Initiation. Session Initiation Protocol

Identity based Authentication in Session Initiation. Session Initiation Protocol Identity based Authentication in Session Initiation by Harsh Kupwade Southern Methodist University Dean Willis Softarmor LLC Thomas M. Chen Swansea University Nhut Nguyen Samsung Telecommunications 1 Session

More information

Time has something to tell us about Network Address Translation

Time has something to tell us about Network Address Translation Time has something to tell us about Network Address Translation Elie Bursztein Abstract In this paper we introduce a new technique to count the number of hosts behind a NAT. This technique based on TCP

More information

Agent-Oriented Software Engineering PORTO Methodology AIAD 2013/2014. António Castro and Eugénio Oliveira

Agent-Oriented Software Engineering PORTO Methodology AIAD 2013/2014. António Castro and Eugénio Oliveira Agent-Oriented Software Engineering PORTO Methodology AIAD 2013/2014 António Castro and Eugénio Oliveira NIAD&R Distributed Artificial Intelligence and Robotics Group 1 Contents What is AOSE? Main Existing

More information

St S a t ck a ck nd Qu Q eue 1

St S a t ck a ck nd Qu Q eue 1 Stack and Queue 1 Stack Data structure with Last-In First-Out (LIFO) behavior In Out C B A B C 2 Typical Operations Pop on Stack Push isempty: determines if the stack has no elements isfull: determines

More information

Research and Implementation of Single Sign-On Mechanism for ASP Pattern *

Research and Implementation of Single Sign-On Mechanism for ASP Pattern * Research and Implementation of Single Sign-On Mechanism for ASP Pattern * Bo Li, Sheng Ge, Tian-yu Wo, and Dian-fu Ma Computer Institute, BeiHang University, PO Box 9-32 Beijing 100083 Abstract Software

More information

Analysis of a Search Algorithm

Analysis of a Search Algorithm CSE 326 Lecture 4: Lists and Stacks 1. Agfgd 2. Dgsdsfd 3. Hdffdsf 4. Sdfgsfdg 5. Tefsdgass We will review: Analysis: Searching a sorted array (from last time) List ADT: Insert, Delete, Find, First, Kth,

More information

Oracle Health Sciences Network Patient Recruiter Cloud Service Services Description Version: 2.0 Effective Date: 01-April-2013

Oracle Health Sciences Network Patient Recruiter Cloud Service Services Description Version: 2.0 Effective Date: 01-April-2013 Oracle Health Sciences Network Patient Recruiter Cloud Service Services Description Version: 2.0 Effective Date: 01-April-2013 Oracle Health Sciences Network Patient Recruiter Cloud Service - Services

More information

An Application Framework for Open Application Development and Distribution in Pervasive Display Networks

An Application Framework for Open Application Development and Distribution in Pervasive Display Networks An Application Framework for Open Application Development and Distribution in Pervasive Display Networks (Short Paper) Constantin Taivan and Rui José University of Minho, Department of Information Systems,

More information

HW3: Programming with stacks

HW3: Programming with stacks HW3: Programming with stacks Due: 12PM, Noon Thursday, September 18 Total: 20pts You may do this assignment with one other student. A team of two members must practice pair programming. Pair programming

More information

TheworkreportedinthispaperhasbeenfundedinpartbytheCooperativeResearchCentresProgramthroughtheDepartmentofthePrimeMinisterandCabinetoftheCommonwealth

TheworkreportedinthispaperhasbeenfundedinpartbytheCooperativeResearchCentresProgramthroughtheDepartmentofthePrimeMinisterandCabinetoftheCommonwealth InternationalJournalofCooperativeInformationSystems fcworldscienticpublishingcompany DepartmentofComputerScienceandElectricalEngineering ShaziaW.Sadiq,OliveraMarjanovic,MariaE.Orlowska TheUniversityofQueensland,QLD4072Australia

More information

Reducing Certificate Revocation Cost using NPKI

Reducing Certificate Revocation Cost using NPKI Reducing Certificate Revocation Cost using NPKI Albert Levi and Çetin Kaya Koç Oregon State University, Electrical and Computer Engineering Dept., Information Security Lab, Corvallis, Oregon, USA levi@ece.orst.edu

More information

Programming with Data Structures

Programming with Data Structures Programming with Data Structures CMPSCI 187 Spring 2016 Please find a seat Try to sit close to the center (the room will be pretty full!) Turn off or silence your mobile phone Turn off your other internet-enabled

More information

2.3 Product Manual Models: 400, 500, 500 R, and 1000

2.3 Product Manual Models: 400, 500, 500 R, and 1000 MiraLinkCorporation 2.3ProductManual Models:400,500,500 R,and1000 2006MiraLinkCorporation AllRightsReserved. MiraLink andintellibuffer aretrademarksofthemiralinkcorporation. DocumentID:2.0.7 LicenseAgreement

More information

Renementandvericationofconcurrentsystemsspecied TechnischeUniversitatBerlin,FBInformatik,FGSoftwaretechnik, GraemeSmithandJohnDerricky inobject-zandcsp ycomputinglaboratory,universityofkent,canterbury,ct27nf,uk.

More information

Paillier Threshold Encryption Toolbox

Paillier Threshold Encryption Toolbox Paillier Threshold Encryption Toolbox October 23, 2010 1 Introduction Following a desire for secure (encrypted) multiparty computation, the University of Texas at Dallas Data Security and Privacy Lab created

More information

Queues Outline and Required Reading: Queues ( 4.2 except 4.2.4) COSC 2011, Fall 2003, Section A Instructor: N. Vlajic

Queues Outline and Required Reading: Queues ( 4.2 except 4.2.4) COSC 2011, Fall 2003, Section A Instructor: N. Vlajic Queues Outline and Required Reading: Queues ( 4. except 4..4) COSC, Fall 3, Section A Instructor: N. Vlajic Queue ADT Queue linear data structure organized according to first-in/first-out (FIFO) principle!

More information

User Setup for SQL Security

User Setup for SQL Security User Setup for SQL Security This section describes SQL security needed for MoversSuite and Microsoft Dynamics GP users. SQL Security for MoversSuite Users MoversSuite integrates with Windows Authentication

More information

IS ACADEMIC OPEN SOURCE SOFTWARE DEPENDABLE?

IS ACADEMIC OPEN SOURCE SOFTWARE DEPENDABLE? IS ACADEMIC OPEN SOURCE SOFTWARE DEPENDABLE? Shigeru Chiba Tokyo Institute of Technology, W8-50, Ohkayama 2-12-1, Meguro-ku, Tokyo 152-8552, Japan chiba@acm.org Abstract Keywords: I have been developing

More information

A Blueprint for Universal Trust Management Services

A Blueprint for Universal Trust Management Services A Blueprint for Universal Trust Management Services Tomasz Kaszuba Krzysztof Rzadca Adam Wierzbicki Grzegorz Wierzowiecki Polish-Japanese Institute of Information Technology Warsaw, Poland adamw@pjwstk.edu.pl

More information

How to set up as VPN Network

How to set up as VPN Network How to set up as VPN Network 1 Network and Sharing Firstly open the network and sharing centre by opening control panel and selecting Network and Sharing Center. If Network and Sharing cannot be found

More information

ISSUES IN RULE BASED KNOWLEDGE DISCOVERING PROCESS

ISSUES IN RULE BASED KNOWLEDGE DISCOVERING PROCESS Advances and Applications in Statistical Sciences Proceedings of The IV Meeting on Dynamics of Social and Economic Systems Volume 2, Issue 2, 2010, Pages 303-314 2010 Mili Publications ISSUES IN RULE BASED

More information

1. Systematic literature review

1. Systematic literature review 1. Systematic literature review Details about population, intervention, outcomes, databases searched, search strings, inclusion exclusion criteria are presented here. The aim of systematic literature review

More information

For background on the purpose and positioning of the role, see the Job Description Suggested ECVET credit points: <20

For background on the purpose and positioning of the role, see the Job Description Suggested ECVET credit points: <20 The IT Security Co-ordinator Qualification For background on the purpose and positioning of the role, see the Job Description Suggested ECVET credit points:

More information

MPR 1 Use a performance management system to monitor achievement of organizational objectives.

MPR 1 Use a performance management system to monitor achievement of organizational objectives. MPR 1 Use a performance management system to monitor achievement of organizational objectives. Reference: PHAB Standards and Measures 1.5, Standard 9.1 Indicator 1.1 Staff at all organizational levels

More information

A secure email login system using virtual password

A secure email login system using virtual password A secure email login system using virtual password Bhavin Tanti 1,Nishant Doshi 2 1 9seriesSoftwares, Ahmedabad,Gujarat,India 1 {bhavintanti@gmail.com} 2 SVNIT, Surat,Gujarat,India 2 {doshinikki2004@gmail.com}

More information

Print Manager Plus 2010 How to Migrate your Database to a New SQL or Print Server

Print Manager Plus 2010 How to Migrate your Database to a New SQL or Print Server 1) Make a Copy of the Existing PMP SQL Database Files. 2) Upgrade PMP by running the installer on the old server 3) Install SQL 2005 or 2008 SQL server on the New Server (you may also use the PMP 2010

More information

A Probabilistic Quantum Key Transfer Protocol

A Probabilistic Quantum Key Transfer Protocol A Probabilistic Quantum Key Transfer Protocol Abhishek Parakh Nebraska University Center for Information Assurance University of Nebraska at Omaha Omaha, NE 6818 Email: aparakh@unomaha.edu August 9, 01

More information

CFAS1.3 Use databases to support sales activities

CFAS1.3 Use databases to support sales activities Overview This unit is all about how you use databases to store, analyse and provide information that is useful to the sales process. The unit covers the full process of designing, setting up, populating,

More information

Software Defined Active Queue Management

Software Defined Active Queue Management Software Defined Active Queue Management Future Networks 2014 Sebastian Meier sebastian.meier@ikr.uni-stuttgart.de 2014-09-26 Universität Stuttgart Institute of Communication Networks and Computer Engineering

More information

A Real-Time Cloud Based Model for Mass Email Delivery

A Real-Time Cloud Based Model for Mass Email Delivery A Real-Time Cloud Based Model for Mass Email Delivery Nyirabahizi Assouma, Mauricio Gomez, Seung-Bae Yang, and Eui-Nam Huh Department of Computer Engineering Kyung Hee University Suwon, South Korea {assouma,mgomez,johnhuh}@khu.ac.kr,

More information

Self Insured / Large Deductible Compensator

Self Insured / Large Deductible Compensator Self Insured / Large Deductible Compensator May 2013 Self Insured / Large Deductible This document provides guidance on the set up options in the Claims Portal available to self insured organisations or

More information

The Authentication and Processing Performance of Session Initiation Protocol (SIP) Based Multi-party Secure Closed Conference System

The Authentication and Processing Performance of Session Initiation Protocol (SIP) Based Multi-party Secure Closed Conference System The Authentication and Processing Performance of Session Initiation Protocol () Based Multi-party Secure Closed Conference System Jongkyung Kim 1, Hyuncheol Kim 1, Seongjin Ahn 2, and Jinwook Chung 1 1

More information

Slinger Jansen Visting: University College London Home institution: UtrechtUniversity. i.e., the processes of:

Slinger Jansen Visting: University College London Home institution: UtrechtUniversity. i.e., the processes of: Programme Introduction to Software and Configuration Updating CCU Model description Enterprise Information Systems for Software Vendors: bringing the vendor and customer closer together An enterprise information

More information

Master of Science Business Information Systems. Agile Processes Combining Business Processes and Business Rules

Master of Science Business Information Systems. Agile Processes Combining Business Processes and Business Rules Master of Science Business Information Systems Agile Processes Combining Business Processes and Business Rules Knowledge and Processes knowledge about processes: workflow roles process logic used at design

More information

NormalizingIncompleteDatabases

NormalizingIncompleteDatabases NormalizingIncompleteDatabases Abstract 600MountainAvenue,MurrayHill,NJ07974USA E-mail:libkin@research.att.com AT&TBellLaboratories LeonidLibkin Databasesareoftenincompletebecauseofthepresence ofdisjunctiveinformation,duetoconicts,partialknowledgeandotherreasons.queriesagainstsuchdatabaseswithnullvalues[akg91,il84],isdisjunctiveinforticsofsuchdatabasesandprovenormalizationtheorems

More information

Research and Design of Heterogeneous Data Exchange System in E-Government Based on XML

Research and Design of Heterogeneous Data Exchange System in E-Government Based on XML Research and Design of Heterogeneous Data Exchange System in E-Government Based on XML Huaiwen He, Yi Zheng, and Yihong Yang School of Computer, University of Electronic Science and Technology of China,

More information

Object-Oriented Type Inference

Object-Oriented Type Inference Object-Oriented Type Inference Jens Palsberg and Michael I Schwartzbach palsberg@daimiaaudk and mis@daimiaaudk Computer Science Department, Aarhus University Ny Munkegade, DK-8000 Århus C, Denmark Abstract

More information

Characterization and Modeling of Packet Loss of a VoIP Communication

Characterization and Modeling of Packet Loss of a VoIP Communication Characterization and Modeling of Packet Loss of a VoIP Communication L. Estrada, D. Torres, H. Toral Abstract In this work, a characterization and modeling of packet loss of a Voice over Internet Protocol

More information

Internet Single Sign-On Systems

Internet Single Sign-On Systems Internet Single Sign-On Systems Radovan SEMANČÍK nlight, s.r.o. Súľovská 34, 812 05 Bratislava, Slovak Republic semancik@nlight.sk Abstract. This document describes the requirements and general principles

More information

Quosal Form Designer Training Documentation

Quosal Form Designer Training Documentation Chapter 4 Advanced Form Design Concepts There is a huge amount of customization that can be done with the Report Designer, and basic quote forms only scratch the surface. Learning how to use the advanced

More information

A Comprehensive Study on Cloud Computing Standardization

A Comprehensive Study on Cloud Computing Standardization A Comprehensive Study on Cloud Computing Standardization Dr. Mukesh Chandra Negi Project Manager, Tech Mahindra Ltd, Noida, India ABSTRACT: Standard is a trust between standardization body, buyers and

More information

Accounting for Government Grants

Accounting for Government Grants 124 Accounting Standard (AS) 12 Accounting for Government Grants Contents INTRODUCTION Paragraphs 1-3 Definitions 3 EXPLANATION 4-12 Accounting Treatment of Government Grants 5-11 Capital Approach versus

More information

FINRMFS9 Facilitate Business Continuity Planning and disaster recovery for a financial services organisation

FINRMFS9 Facilitate Business Continuity Planning and disaster recovery for a financial services organisation Facilitate Business Continuity Planning and disaster recovery for a Overview This unit is suitable for those working in risk management roles who have responsibility for facilitating business continuity

More information

SCADA System Security, Complexity, and Security Proof

SCADA System Security, Complexity, and Security Proof SCADA System Security, Complexity, and Security Proof Reda Shbib, Shikun Zhou, Khalil Alkadhimi School of Engineering, University of Portsmouth, Portsmouth, UK {reda.shbib,shikun.zhou,khalil.alkadhimi}@port.ac.uk

More information

A Secure Internet Service for Delivering Documents for the Blind

A Secure Internet Service for Delivering Documents for the Blind A Secure Internet Service for Delivering Documents for the Blind Benoit Guillon 1, Dominique Burger 1, and Bruno Marmol 2 1 Université Pierre et Marie Curie B23, INSERM U483, 75252 Paris Cedex, France

More information

Continuous Quality Improvement Process Tailored for the School Nutrition Environment

Continuous Quality Improvement Process Tailored for the School Nutrition Environment National Food Service Management Institute The University of Mississippi Continuous Quality Improvement Process Tailored for the School Nutrition Environment Applied Research Division The University of

More information

VoIP Usage. 2010 Connected Tennessee. All Rights Reserved. Do Not Copy Without Written Permission.

VoIP Usage. 2010 Connected Tennessee. All Rights Reserved. Do Not Copy Without Written Permission. VoIP Usage 2010 Connected Tennessee. All Rights Reserved. Do Not Copy Without Written Permission. 83 Businesses that Report Using Voice over Internet Protocol (VoIP) Only a small percentage (6%) of Tennessee

More information