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Josep Carmona Boudewijn van Dongen Andreas Solti Matthias Weidlich Conformance Checking Relating Processes and Models Conformance Checking Josep Carmona • Boudewijn van Dongen (cid:129) Andreas Solti (cid:129) Matthias Weidlich Conformance Checking Relating Processes and Models 123 JosepCarmona BoudewijnvanDongen DepartmentofComputerScience DeptofMathematicsandComputerScience UniversitatPolite`cnicadeCatalunya TechnischeUniversiteitEindhoven Barcelona,Spain Eindhoven,TheNetherlands AndreasSolti MatthiasWeidlich InstituteforInformationBusiness DepartmentofComputerScience ViennaUniversityofEconomics Humboldt-Universita¨tzuBerlin andBusiness Berlin,Germany Vienna,Austria ISBN978-3-319-99413-0 ISBN978-3-319-99414-7 (eBook) https://doi.org/10.1007/978-3-319-99414-7 LibraryofCongressControlNumber:2018956267 ©SpringerNatureSwitzerlandAG2018 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped. Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant protectivelawsandregulationsandthereforefreeforgeneraluse. Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthisbook arebelievedtobetrueandaccurateatthedateofpublication.Neitherthepublishernortheauthorsor theeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinorforany errorsoromissionsthatmayhavebeenmade.Thepublisherremainsneutralwithregardtojurisdictional claimsinpublishedmapsandinstitutionalaffiliations. ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSwitzerlandAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Foreword Conformance checking is an important—but also challenging—topic in process mining. Most people who see process mining for the first time are dazzled by theprocessdiscoverycapabilitiesoftoday’sprocessminingtools.However,when people really start to use process mining, more detailed questions emerge, and it is no longer sufficient to look at fancy process diagrams composed of boxes and arrows.Initially,onlyacademictoolslikeProMsupportedconformancechecking. However,inthelasttwoyears,alsocommercialtoolsstartedtosupportconformance checking,andthisisagreatdevelopment.Moreover,itiswonderfulthatthereisnow thisbookdedicatedtoconformancecheckingwrittenbymydearcolleaguesJosep Carmona,BoudewijnvanDongen,AndreasSolti,andMatthiasWeidlich.Thebook nicely complements my earlier Springer book “Process Mining: Data Science in Action” by diving deep into the topic of conformance checking and giving it the attentionitneeds. Process mining relates event data and process models and bridges the gap between data science and process science. It is a very natural, and seemingly obvious, combination of forces. Most organizations have a continuous desire to improvetheir processesand with the availability of data it makessense to do this in an evidence-based manner. On the one hand, it aligns well with the current excitement about Big data, machine learning, and artificial intelligence. On the other hand, the techniques used are very different as demonstrated in this book. We already had two “AI Winters” (1974–1980and 1987–1993),and I’m sure the third one is not far away. Therefore, it is important to see that process mining is verydifferentandalsoveryconcrete(asopposedtosomeofthehypedAItopics). When people see process miningfor the first time, they wonderwhy they did not hearaboutthisbefore.Thisbookwillhopefullycontributetoabetterpositioningof thetopic. ProcessminingresearchatEindhovenUniversityofTechnologystartedin1999. The focus in the first year was on process discovery, and algorithms like the α- miner and the heuristic miner were developed. We started to systematically work on conformance checking in 2004 in the context of Anne Rozinat’s PhD thesis. Beforethis,weonlycompared“footprintmatrices”andimplementedadhocfitness v vi Foreword functions in the context of genetic algorithms. Anne’s seminal work resulted in the token-based replay techniques also described in this book. Conformance was expressed in terms of missing and remaining tokens. Several other notions were developedinthisperiod(e.g.,variantsofwhatistodaycalledprecision)andtoken- basedreplaybecamethestandard,notonlyforconformancechecking,butalsofor decisionminingandperformanceanalysis.However,asalreadypointedoutinAnne Rozinat’s PhD thesis, token-based replay has several limitations. The next major breakthroughwas realized in the contextof Arya Adriansyah’sPhD work (2009– 2013). He developed the seminal notion of alignments which is one of the main topicsinthisbook.Alignmentsprovidea“closestpath”throughtheprocessmodel. It can be turned into a shortest-path problem by creating a kind of synchronous productbetweentheeventlogandtheprocessmodel. PartIIofthisbookusesalignmentsasa centralnotionandtakesa “deepdive” into the world of conformance checking (including linear algebraic techniques, heuristic search, and decompositions). The different chapters demonstrate that conformance checking is very different from traditional model-based process analysis(e.g.,simulationand otherbusiness processmanagementtechniques)and data-centric analysis techniques such as machine learning and data mining. The confrontation between event data (i.e., recorded behaviour) and process models (hand-made or discovered automatically) triggers many interesting and highly relevantquestions. Part III of the book zooms in on the applications of process mining and corresponding tools. Aligning recorded behaviour and modelled behaviour is relevant in any domain where event data are collected, including logistics, manu- facturing, finance, healthcare, customer relationship management, e-learning, and e-government. Moreover, decision mining and bottleneck analysis depend on it. For example, the profession of auditors will dramatically change because of conformancechecking.Undoubtedly,conformancecheckingwillbeinthetoolbox of futuregenerationsof analysts,consultants,managers,processowners,software engineers,etc. How about the future of conformance checking? What lies ahead? There is broad consensus among process mining experts that conformance checking will become more important. This providestwo main challenges: (1) How to improve the performance of conformance checking when models and logs get bigger? (2) How to balance between precision and deliberate vagueness? Compared to state-of-the-art discovery techniques, conformance checking techniques tend to be time-consuming. It is not always required to compute optimal alignments and there is room for approximations or alternative conformance notions. Existing conformance approaches also require formal models. However, this is in stark contrast with the informal models generated by commercials tools. When there is not enough evidence in the data, one should not show very strict and “binary” process-model constructs. However, if there is enough evidence in the data, one shouldnotuseprocess-modelconstructswithoutclearsemantics.Someofthetools resolve this by having two types of process models: one for discovery and one for conformance checking. Obviously, this is only a temporary solution. Process Foreword vii miningtoolsneedtosupporthybridprocessmodelsthatareprecisewhenpossible and vague when needed. Such models should also take into account probabilities of process paths. These challenges show that conformance checking continues to providewonderfulopportunitiesforresearchers. IwouldliketocongratulateJosep,Boudewijn,Andreas,andMatthiaswithdoing anexcellentjobinjoiningthestate-of-the-artapproachesinasinglebook.Thebook willbeareferenceforpeopleinterestedintheintricaterelationshipbetweenmodels andreality.Enjoyreading! RWTHAachenUniversity Prof.Dr.Ir.WilvanderAalst Aachen,Germany March2018 Preface A model is an artefact to represent a specific concept. It maps properties of the conceptinto some abstractrepresentation,drivenbythe purposeof the model.As such, models represent a universal means to capture concepts in a wide range of domains:Inarchitecture,amodelmayrepresenttheoutlineofabuildingstructure; in engineering, a model may capture the mechanics of a pump; and in computer science, a model of a processor may correspond to the hardware supporting a particularsysteminfrastructure.Regardlessofthespecificconceptthatiscaptured, amodelalwayshasapragmaticfeature.Itiscreatedforaspecificpurpose,itmay bethedesignorconstructionoftheconceptoritsanalysisandexploration. Inthisbook,weconsidermodelsofprocesses.Aprocessisasetofactivitiesthat areexecutedinacoordinatedmannertoachieveacertaingoal.Itisveryhardtonot encounteraprocessinmostofthethingswedoinourdailylife:takingthecarto gotowork,extractingmoneyfromanATM,orderinggoodsusinganonlineshop,or visitingthedoctor—allareexamplesofprocesses.Eachoftheminvolvesactivities, whereastheabilitytoreachaspecificgoaldependsontheireffectivecoordination. Processmodelsareavaluablesourceofinformation.Theymaybetheresultofa significanteffortinformalisingacomplexprocess.Thisformalisationencompasses the decision which properties of a process should be mapped into the model. For processes,this decisionprimarilyrelatesto the choice ofthe activitiesto consider andthepossiblewaysinwhichtheycanbeexecuted.However,furtherinformation may be considered, such as the involved actors, the data used or generated, or the timing of the activities. Modelling a real process can only be done if some abstraction is applied. To escape from unnecessary details and retain the essence of the process, only some process properties are mapped to a model. Hence, by definition,modellingincurssomelossofinformation. Yet,thefactthatnotallinformationaboutaprocesscanbecapturedinamodel isnottheonlyreasonthataddstotheuncertaintyintherelationbetweenaprocess modeland the processitself. A modelmay also have been formalised incorrectly, simply became outdated with respect to the process, or describe behaviour that deviatesfromtheactualprocess.Inthepast,thisuncertaintyintherelationbetween aprocessandamodelthereofhasbeenacriticalproblem,whichwashardtodetect. ix x Preface Themassiveavailabilityofdata, however,haschangedthissituationdramatically. Nowadays, systems record the footprints left by executions of the process, which enable data-driven analysis. Therefore, the recorded behaviour of a process, as manifested in so-called event logs, is now available as an important source of information. Conformancecheckingrelatesmodelledandrecordedbehaviourofaprocessto each other. It provides techniques and methods to compare and analyse observed instancesofaprocessinthepresenceofamodel,independentoftheoriginofthat model.Conformancecheckingthereforeaimsatansweringquestions,suchas: (cid:129) Istheprocessbeingexecutedasitisdocumentedinamodel? (cid:129) Isthemodelofaprocessstillup-to-date? (cid:129) Havetherebeenviolationsofrulesintherecordedinstancesofaprocess? (cid:129) Howmuchflexibilityisallowedintheexecutionofaprocess? Theaimofthisbookistointroducereaderstothefieldofconformancecheckingas awholeandoutlinethefoundationsoftherelationbetweenmodelledandrecorded behaviour.Thebookstrivesforanoverviewoftheessentialtechniquesandmethods in this field on the intuitive level as well as an understanding through a precise formalisationoffundamentalnotionsofconformancechecking. Structure ofThisBook Thisbookisstructuredinthreeparts,eachbeingguidedbyadifferentquestionand thereforeadifferentapproachtothefieldofconformancechecking: Part I: What are the main ideas behind conformance checking? Readers shall benefitfromthefirstpartofthebookasaconciseandcomprehensiveoverviewof theessentialideastorelatemodelledandrecordedbehaviourtoeachother.Thispart servesasareferencetoassesshowconformancecheckingeffortscouldbeapplied in particular domains. Outlining these ideas on the intuitive level, this first part is of interest to students, academics, and practitionersalike, who have a technical background,butarenewtothefieldofconformancechecking. Part II: What are the state-of-the-art methods for conformance checking? The second part of the book aims at providing readers with detailed insights into algorithms for conformance checking. This includes the most commonly used formalnotionsforconformancecheckingandtheirinstantiationforspecificanalysis questions. This part aims at enabling readers to initiate research in conformance checking.Whileallbasicdefinitionsaregivenexplicitly,readersbenefitfromprior knowledgeinformalismsforprocessmodelling,suchasPetrinets. PartIII:Whatarethe applicationsthatbuildontopofconformancechecking? The third part of the book presents applications that help to make sense of conformancecheckingresults, therebyprovidinganecessarynextstep to increase the value of a process model. Specifically, such applications help to interpret the Preface xi results of conformance checking and incorporate them through enhancement and repairtechniques.Thisincludesremarksonconformancecheckingsoftware. TeachingUsingThisBook In the light of the above structure, three itineraries are suggested when using the bookasareferenceforteaching: (cid:129) Chapters1–4and12:Thesechaptersgiveageneraldescriptionofconformance checking,includingremarksontoolsupport,fromapracticalperspective. (cid:129) Chapters5–9:Thispartgivesanalgorithmicviewonhowtorelatemodelledand recordedbehaviour,focusingonformalfoundationsofconformancechecking. (cid:129) Chapters1–6and10–12:Anend-to-endviewonconformancecheckingandits applications,coveringformalfoundationsonthebasiclevel. Thechaptersofthebookincorporatematerialinthefollowingform: (cid:129) Each chapter contains teaching material in the form of exercises to allow for effectivelearningofthetheoreticalconceptsintroduced. (cid:129) For those chapters amenable for tool practising, a section namedIn the Lab is included,whichintroducestoolsand/ordatasetsforexploringthecontentsofthe chapteronrealdata. Websiteofthebook Check out the website for teaching materials for the book. Throughout thebook,youfindlinkstosupportlab sessionsforspecificchapters. http://www.conformancechecking.com/CC_book Barcelona,Spain JosepCarmona Eindhoven,TheNetherlands BoudewijnvanDongen Vienna,Austria AndreasSolti Berlin,Germany MatthiasWeidlich