Urban Open Platform for Borderless Smart Cities

Abstract

As a network of connected sensors to transform data into knowledge, Urban Platforms have been rooted in several smart city projects. However, this has often resulted in them being no more than IoT dashboards. More recently, there has been an increased interest in supporting the data governance and distributed architecture of Urban Platforms in order to adjust these with the administrative structure in a specific city. In addition, Urban Platforms also deal with data roaming between different stakeholders including other cities, different government levels, companies and citizens. Nevertheless, the first deployments have led to an inflexible "smart cities in a box" approach that does not help with building digital skills and causes vendor lock-in to products that do not scale. There is a need to start with simple and widespread urban services through a collaborative joint cross-border, hands-on effort. In order to meet the level of interoperability, international standards should be adopted. The aim of an Urban Open Platform (UOP), introduced in this paper, is to support not only data acquisition but also various types of data processing: data is aggregated, processed , manipulated and extended within the city context. Conceptually, special attention has been put on scalability, roaming and reliability in urban environments. This article introduces the UOP uniquely in the cross-border data exchange context of two European capital cities, Helsinki and Tallinn, and validates it with 10 real-life urban use cases.

Full text

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Appl.Sci.2022,12,700.https://doi.org/10.3390/app12020700www.mdpi.com/journal/applsci
Article
UrbanOpenPlatformforBorderlessSmartCities
Ralf‐MartinSoe
1
,TimoRuohomäki
2
andHenryPatzig
1,
*
1
FinEstCentreforSmartCities,TallinnUniversityofTechnology,Ehitajatetee5,19086Tallinn,Estonia;
ralf‐martin.soe@taltech.ee
2
ForumViriumHelsinki,Unioninkatu24,00130Helsinki,Finland;timo.ruohomaki@forumvirium.fi
*Correspondence:henry.patzig@taltech.ee
Abstract:Asanetworkofconnectedsensorstotransformdataintoknowledge,UrbanPlatforms
havebeenrootedinseveralsmartcityprojects.However,thishasoftenresultedinthembeingno
morethanIoTdashboards.Morerecently,therehasbeenanincreasedinterestinsupportingthe
datagovernanceanddistributedarchitectureofUrbanPlatformsinordertoadjustthesewiththe
administrativestructureinaspecificcity.Inaddition,UrbanPlatformsalsodealwithdataroaming
betweendifferentstakeholdersincludingothercities,differentgovernmentlevels,companiesand
citizens.Nevertheless,thefirstdeploymentshaveledtoaninflexible“smartcitiesinabox”ap‐
proachthatdoesnothelpwithbuildingdigitalskillsandcausesvendorlock‐intoproductsthatdo
notscale.Thereisaneedtostartwithsimpleandwidespreadurbanservicesthroughacollaborative
jointcross‐border,hands‐oneffort.Inordertomeetthelevelofinteroperability,internationalstand‐
ardsshouldbeadopted.TheaimofanUrbanOpenPlatform(UOP),introducedinthispaper,isto
supportnotonlydataacquisitionbutalsovarioustypesofdataprocessing:dataisaggregated,pro‐
cessed,manipulatedandextendedwithinthecitycontext.Conceptually,specialattentionhasbeen
putonscalability,roamingandreliabilityinurbanenvironments.ThisarticleintroducestheUOP
uniquelyinthecross‐borderdataexchangecontextoftwoEuropeancapitalcities,Helsinkiand
Tallinn,andvalidatesitwith10real‐lifeurbanusecases.
Keywords:smartcity;dataplatform;dataanalytics;dataproduct;digitaltwin;datamesh

1.Introduction
Thispaperismotivatedbythechallengethatthecapabilitiestocollectanduseurban
datasourcesarelow,whileatthesametimethevolumeofdataisconstantlyincreasing.
Thisalsoappliestotechnicalcompetencesfordataprocessinganddataanalysis.Thisis
accordingtoasurveyconductedwithEstonianmunicipalities(https://taltech.ee/en/finest‐
centre‐for‐smart‐cities#p34631,accessedon6January2022)inaEuropeancountrywith
oneofthemostadvanceddigitalpublicservices,accordingtothepan‐EuropeanDESI
Index,whichprobablypointstotheglobalnatureofthischallenge.Inthislight,wehave
investigatedwhichdatacollectionandanalysistoolscitiescouldusetodealwiththis
problem,startingwithusecasesinEstoniaandFinland.Inaddition,theissueismuch
morecomplexwhenwestartanalysingcross‐bordercitiesandtheirdataexchange,call‐
ingforresearch‐basedsolutions.Therefore,themaincontributionofthispaperisanat‐
tempttobringthelevelofanalysisfromthesingle‐cityUrbanPlatformtothemultiple‐
citieslevel.
Data,includingthemeansofprocessingit,isnotanewphenomenonforcities—this
hasbeenatthecentralofurbangovernancesincetheindustrialrevolutionbeganinthe
19thcentury[1].Therefore,thekeyquestionishowitischanginginthecontextofdigital
technologiesthatareredrawingthebordersbetweencities,countriesandcompanies;at
leastthevirtualborders.Thispaperinvestigateshowdatacanbeexchanged,bothwithin
onecityandalsoacrosscitiesandtheirstakeholders.Digitaltechnologybreakthroughs
suchasFacebook,Skype,GoogleandLinkedInhaveclearlychangedtheunderstanding
Citation:Soe,R.‐M.;Ruohomäki,T.;
Patzig,H.UrbanOpenPlatformfor
BorderlessSmartCities.Appl.Sci.
2022,12,700.https://doi.org/10.3390/
app12020700
AcademicEditors:GianniPantaleo
andPierfrancescoBellini
Received:11November2021
Accepted:4January2022
Published:11January2022
Publisher’sNote:MDPIstaysneu‐
tralwithregardtojurisdictional
claimsinpublishedmapsandinstitu‐
tionalaffiliations.

Copyright:©2022bytheauthors.Li‐
censeeMDPI,Basel,Switzerland.
Thisarticleisanopenaccessarticle
distributedunderthetermsandcon‐
ditionsoftheCreativeCommonsAt‐
tribution(CCBY)license(https://cre‐
ativecommons.org/licenses/by/4.0/).

Appl.Sci.2022,12,7002of14
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oftheworldmap:ifoneisonline,therearenoborders,atleastinonlinecommunications
services.Ontheotherhand,thepictureisdifferentifzoomedintourbanlevelswhereeach
departmentineachmunicipalitytailorsitsownelectronicservices.Localservicesareof‐
tendevelopedinisolationwithminimalattemptstoco‐designtheservicesjointlywith
otherkeystakeholders(othercities,differentgovernmentlevels,companies,citizens,etc.).
Furthermore,digitalurbanservicesareoftendevelopedandanalysedfromthe“closed‐
borders”perspective,disregarding,forexample,everydaycommutersfromotherregions
andthefactthat,atleasttechnologically,servicesanddatacanbescaledoverinstitutional
borders[2].
AccordingtoEickeretal.[3],anUrbanPlatform(UP)isakeysoftwareinfrastructure
forurbanplanningandmaintenance,designedtohandleandanalyselargedatasetsfrom
differentdomains.Theauthorsarguethatthemaindrivershouldbetohelpcitiesfollow
zerocarbonstrategiesviatheinclusionofallmajorsectorsofCO2generation.Similarly,
Hernándezetal.[4]seetheendgoalofthedigitalisationofcitiesistobecomemoreenvi‐
ronmentallyfriendly,whichasaprocesscanbeachievedviatheOpenStandardizedUr‐
banPlatformwiththemainfunctionalitiesofdataingestion,analyticsandservices.Badidi
&Maheswaran[5]andChengetal.[6]putthedeploymentofsensorsasbeingmorecentral
inUrbanPlatforms’applications,withtheendgoaltoimprovethequalityoflife.The
widergoalistoenablethetransitionofcitiestomoresustainablesystems(lessCO2,more
energyefficient,moreenvironmentallyfriendly,etc.—allbetterforthecitizen).Neverthe‐
less,therearestillstructuralobstaclessuchasopennessandinteroperabilityinthoseUr‐
banPlatforms.TheissueisbroughtoutbyLee,Mackenzie,Smith,&Box[7],whomapped
100urbandatapracticesthatcontributeto“platformurbanism”bynotingaconcerndy‐
namicofcityadministratorstobe”lockedin”tospecificcorporateproductsandinterests.
Inaddition,Badidi&Maheswaran[5]arguethatdatainteroperabilityandintegrationis
themostchallengingsmartcityproblem.
Ingeneral,theliteratureonbigdataclassifiessourcesunderthreebroadcategories:
opportunisticsensing,purposelysensingandcrowdsensing[8].Opportunisticsensing
leveragesdatarunningonexistingsystems,suchasatelecommunicationnetwork,but
canbeusedtobetterunderstanddifferentsystems.Inotherwords,dataiscollectedfor
onepurposeandusedforanother.Thisapproachtodatacollectionismadepossible
largelybythefactthatmobilephoneshavebecomeubiquitous(www.itu.int/ITU‐
D/ict/material/Telecom09_flyer.pdf,accesson06January2022)—citizensreplacetheneed
forpurpose‐builtsensors,contributingreal‐timedatathroughtheirportabledevices.
Othertypicaldataprovidersincludecreditcardcompaniesrecordingusertransactions,
taxifleetsreportingvehicleGPSs,etc.Incontrasttoopportunisticsensing,purposely
senseddatasetsarederivedfromadhocsensornetworksconfiguredtostudyaspecific
phenomenon.Thankstoadvancesinmicroelectronicssensors,computationsarebecom‐
ingincreasinglyaffordableanddistributed,aphenomenonoftenreferredtoas“smart
dust”.Hence,networksofremotesensingagentscannowbeembeddedinthecityfabric
toextractlargeamountsofinformation.Thisdataischannelledintocentralcontrolsta‐
tionswhereitisaggregated,analysedandusedtomakedecisionsonhowthemonitored
terrainshouldberegulatedandactuated.Here,theresultingdatasetstendtobemore
uniform,withthestateduseandactualend‐usescenariosbetteralignedtodecodevarious
flowswithinthecity.
Ineverycity,thecompletestorycannotbetoldbyfiguresanddataalone.Toade‐
quatelyassessasituation,thevoiceofthecitizenmustbeheard.Eachurbanitecanbe
thoughtofasahumansensor,capableofreportingontheirexperienceofthecitythrough
content‐sharingplatformssuchasFlickr,Twitter,FacebookorWikipedia[9].Theseac‐
tionsofferauniqueviewofhowcitizensnavigatetheirenvironment,bringingclarityto
pointsofattractionorspontaneousmigration.Thisapproachdescribesthethirddata
sourceknownascrowdsensing.Thecrowdbecomesadistributednetworkofsensorsthat
allowsunderstandingthedynamicpatternsofthecityandtheexperiencesofitscitizens

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ataquasi‐real‐timerate.Intheabsenceorfailureoftop‐downsensornetworks,thisgrass‐
rootsapproachtosensingleveragesthemillionsofnewlycyber‐connectedcitizenstoco‐
ordinatehumanactivityonanunprecedentedscale.Integratedcitiesperformwithunpar‐
alleledefficiency(whetherresources,transportationorinfrastructure),enabledbydigi‐
tallycontrolledcircuitryandvirtualoperatingsystems,ultimatelytransformingurban
spaceintoanopenlivinglab.
However,thequestionremainstowhatextentUrbanPlatformsattractparticipation
ofcitizensintheprovisionofbetterservices.Inonestudy,citizene‐participationwaspos‐
itivelyassociatedwiththeclearancerateofurbanservicerequests,althoughtheeffectsize
ofparticipatoryserviceperformancevariesbetweendifferenttypesofcityservices—there
wasmoreinvolvementincomplexproblemscomparedtosimpleroutineservices[10].
Importantly,UrbanPlatformscanalsobeindependentfromthedirectroleofthecitygov‐
ernment.Velsberg,Westergren,&Jonsson[11]focusontheconceptof“smartness”inthe
contextofserviceprovision,reflectingtheambitionofthepublicsectortobecomemore
agileandresilientwhenapplyingnoveltechnologiessuchastheInternetofThings—also
centraltoUrbanPlatforms.
TheInternetofThings(IoT)isaconceptforconnectingvarioussensorstotheInternet
usingbigdataanalytics[12]withapplicationsinsmartcities[13];itcan,atleasttheoreti‐
cally,improvetheurbanservicesandreduceresourcesconsumption[14].Therearealso
papersthattakeamorecriticalorrealisticapproachbyclaimingthatbuildinglarge‐scale
smartcityIoTplatformsremainsempiricallychallenging[15],inadditiontochallengesof
howtosolvetheprivacyrightsofresidents[16].
AccordingtoBarns[17],platformsplayagrowingstrategicroleinthedailylivesof
citiesviamatchmakingbetweensubjects,whetherformobility,accommodation,shop‐
pingandevendating,makingtheseplatformswiderdataecosystemsofusers,producers
andconsumers.Nevertheless,thereisalackofresearchinunderstandingtheoperational
modeloftheUrbanPlatformthathasdifferentgoalsthatalsocanbeinconflict,e.g.,city
internaloperationandserviceversuspublishingpublicdata[18].
Thisrestofthispaperisstructuredasfollows:Section2providesanoverviewofthe
visionandarchitectureofUrbanPlatforms,viaintroducingtheconceptoftheUrbanOpen
Platform;Section3appliesthistotheusecaseofthecitiesofTallinnandHelsinki;and
Section4wrapsupwithdiscussionandconclusions.
2.UrbanOpenPlatform:VisionandArchitecture
2.1.TheVisionofUrbanOpenPlatform
ThevisionoftheUrbanOpenPlatform(initiallydevelopedbyCarloRattiAssociati,
underthelabelofUrbanOperatingSystemin2016fortheH2020projectFinEstTwins)is
quitesimple.Deployinganetworkofsensorsthatcancapturereal‐timedatafromamyr‐
iadofoccurrencesinthecityandconnectingsuchsensorstoanurbaninformationsystem
helpstobetteranalyseandtransformsuchdataintoknowledge(seeFigure1).Asaresult,
newtypesofurbanefficiencies,productsandservicesforcitydwellerscanbecreated.In
turn,userscanaccessanopen‐accessdigitalservicesdeliveryplatformviaasmartphone
orlaptopallthewayuptodigitallyenhancedinfrastructuressuchasresponsivepublic
spaces,intelligenttransportsystemsorsmartenergyinfrastructure.Thecitybecomesa
permanentplatformforinteraction,providingauniquemixofservicestoeachuser.Fur‐
thermore,bygivingusersthecapabilitytodeveloptheirownsolutionsandservices,a
moreinclusiveandbottom‐upmodelofbothsocialandeconomicdevelopmentwillbe
createdwhilejumpstartinglocaldynamics.
Organisationsthatdesignsystemstendtoreflecttheorganisationalstructureinthe
architecture[19].Inadiverseorganisationsuchasacity,thishascausedchallengesin
boththeenterpriseandthedataarchitecture.Commondatawarehouseshavehadalim‐
itedscope,suchassupportingfinancialandHRfunctions,whiletheoperationalsystems

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remainontheirown.Whendataplatformshavebeencreatedtosupportadvancedana‐
lyticsandbusinessintelligence,theoverallenterprisearchitecturehasbeensplitintotwo
mainfunctions:anoperationalplane(operationalsystems,oftenlegacy)andanalytical
plane(datawarehouses,datalakes,BI).Thelinkbetweenthetwoplaneshastypically
beenanETLprocessdefinedforeachdatapipe.Thelargertheorganisation,themore
challengingthisapproachhasbeentogovernandmaintain.Thevastamountofdatacom‐
inginfromIoTandautomationsystemshasalsoraisedtheconcernwhetheritisfeasible
tostoreeverythingonacentraldatalake.
AnUrbanOpenPlatformshiftsthefocusfromcentricdataplatformstowardscross‐
organisationalcapabilitiesandempoweringdomainspecialistswithdataacquisitionand
manipulationfunctions.Citiescannotforeseeafuturewherehundredsofdataengineers
wouldbeemployedtomanagethenewdatapipelinesrequiredforsituationalawareness.
TheplatformisacollectionofcomponentswithconnectorsandAPIsthatcanbe“wired”
togetherindifferentwaystomeetthevariousandevolvingdataintegrationandcontext
enhancementneeds.Thesetasksshouldnotrequireprogrammingexperiencebutbeavail‐
ablefordomainspecialistsasauser‐friendly,self‐serviceplatform.Thedivisionsandde‐
partmentsofthecitiescancontinuemaintainingtheirowndatamartsandlakes,butpol‐
icymanagementandadvanceddatacatalogueswithdiscoveryoptionsmakeitpossible
toadoptthelayersofdatagovernancebothattheunitandenterpriselevels.Thedata
analyticsintheoperationalplanearesupportedbystreamprocessingcapabilitiesand
datavirtualisation.Withthisapproach,itismorefeasibletoanalyselargeamountsof
data,suchasthecurrentstateofcitystreetlights,withouthavingtocreateamassivetime‐
seriesdatastore.Forthistobeachievable,thefollowingpropertiesmustbeinherentto
thesystem:

Figure1.TheUrbanOpenPlatform.
Architecture:Thedatamanagementlayerprovidesstandardisationandastorage
functionfortheplatform,facilitatingtheanalysisoflong‐termsensordata.TheUOP
wouldbetheprimaryconductorofvariousdatastreamsusedbythevariousdigitalser‐
vicesbetweentwocities.

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Integratingdatastreams:Ubiquitoussensorsandsensornetworkssuchasbuilding
automationsystemsareincreasinglyprovidingdatasourcesofdifferentcontents,formats
andqualities.Integratingdiversedatasourcesallowsdevelopingapplicationsthatwould
notbepossiblebyusingasinglesensornetwork.Whenintegratingdatafromheteroge‐
neoussources,syntactic,schematicandsemanticdiversitiesofthedataschemasarechal‐
lengingproblems.ThepastworkonIoTplatformshasevolvedintogenericcapabilities
supportingreal‐timestreamandeventprocessing.ThroughanUOP,datafromdiverse
sourcesistranslatedintoacommonlanguage,APIsandvisualinterface.Thecapabilities
shiftthefocusfromrawdataacquisitiontowardsreusable,high‐qualitydataproducts.
Dataprocessingfunctionality:TheUOPwillofferbusinesses,citizensandgovern‐
mentssituationalawarenesswiththeabilitytocombinereal‐timedatafromacrosssome
datastreamstocreateanup‐to‐the‐minutepictureofurbanmaterialflowsanddynamics.
Inaddition,carryingdatafromproviderstoconsumers,theUrbanOpenPlatformwill
allowclientstoquicklyprocess,manipulateandvisualisethedataofdatastreams.With
thehelpofopenAPIs,applicationscanalsobepublishedandsharedamongusers.
Scalabilityandflexibility:Agiledevelopmentprocesseshavedramaticallychanged
thewaytechnologyisbeingimplemented.Shortercyclesallowsocietytoconstantlyadapt
tochangeornewconditions.Whenapplicationsandservicesaredevelopedinanagile
fashion,thearchitectureshouldbeevolvingaswell.Fordetal.[20]seethearchitectureas
aconstanteffortthatcanreactbothtochangingrequirementsbutalsotofeedbackfrom
programming.TheUOPwillbedesignedtomeetcurrentneedswithoutcompromising
theabilityoffuturegenerationstomeettheirs.Atthemoment,wecanassumethereare
hundredsofdatastreams,andwithindividualscontributing,thisnumbereasilyrisesinto
thethousands.Takingintoaccounttheoverallinputloadandthenumberofpotential
clients,aquickapproximationindicatesthatwecouldeasilyreachonemillionmessages
persecond.AnUrbanOpenPlatformwillbedesignedtoinitiallydealwithasmallload
but,atthesametime,itwillneedtobedesignedtoscaletohundredsofmachinesto
accommodatetheadditionalload.
Inhabitantsasactors:Trulysmartcitieswillemergeasinhabitantsandtheirmany
electronicdeviceswillberecruitedasreal‐timesensorsofdailylife,agentsforsensingand
reportingtheirindividualexperience.Offeringareal‐timeviewofhowhuman,material,
digitalandfinancialresourcestravelthroughthelandscapeoftheirdailyliveswillper‐
ceptuallyexpandeachcitizen’ssphereofresponsibilityfromthedomesticspacetothe
spaceofthecity,withthecitybecomingthesmartmeterofallthesefactors.Inadigitally
augmentedsmartcity,civiczonescanbetransformedintoresponsiveenvironments
throughtechnologicalmediation.Thiswouldchangethepassiveinhabitantsofthecityto
activeparticipantsofspatialscenariosandthepublicspacesfromareasoftransittourban
destinations.
2.2.UrbanOperatingSystemasaDataPlatform
InrelationtoUrbanPlatforms,therehasbeengrowinginterestinbettersupporting
thedatagovernanceanddistributedarchitecturetobestfittheneedsofhowcitiesoperate
organisation‐wise.Citiesareoftenseenasasingleentitywithasinglevoice,butthisis
notthecaseintermsoftheICTtoolsandplatformsthatcitiesoperateon.Thedepartments
andunitshavehadalotofindependenceintheirchoicesofsystems.Onecoreelementof
theUOPisitsabilitytohandlelegacydatasourcesandavarietyofdataformats.How‐
ever,thedataintegrationcapabilityisastandardrequirementonanydataplatformand
doesnotdependonnewinnovation.Forexample,theextract‐transform‐load(ETL)isa
processthathasbeenaroundsincetheearly1970s.Whatismoredifficulttotackle,how‐
ever,isthegovernance,ownershipandroutesofthedatabetweenthecitydepartments,
platformsandsystemswithmultiplestakeholders.
ThepublishingofopendataonUrbanPlatformshasalsobroughtinproductthink‐
ing,i.e.,seeinganddevelopingtheurbandataasaproduct[21].Ingeneral,datasetsfit
wellwiththedefinitionofproduct:anythingthatcanbeofferedtoamarketforattention,

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acquisition,useorconsumptionthatmightsatisfyawantorneed[22].Dataproductsare
ownedbyproductownerswhomayhaveawiderinterestindefiningthe“features”of
theproduct,includingdataquality,context,documentationindatacatalogues,etc.Data
productisseenasaresultofvalue‐drivenanalysisthatgeneratesaddedvaluefromthe
underlyingdata(https://www.oreilly.com/radar/what‐is‐data‐science,accessedon12
June2018)andiswellalignedwithservicedesignconcepts.Thekeymechanismofvalue
creationistocreateinsightsoutofdatausinganalyticalmethods.
Somerecenttermsintroducedindataplatformdiscussionaredatameshanddatapipe‐
lines.DatameshwasintroducedasaconceptbytechnologyconsultantZhamakDehghani
(https://martinfowler.com/articles/data‐monolith‐to‐mesh.html,accessedon7January
2022).Herkeymessagewasthatdataplatformsbasedonthecentraldatalakearchitecture
havecommonfailuremodesthathavepreventedthemfrombeingscaledupandwidely
used.Hersuggestionwastoconsiderdatadomainswithahigherpriority,toapplyplat‐
formthinkingtocreateself‐servicedatainfrastructureandtotreatthedataasaproduct.
2.3.TheUOP’sWorkingConcept
TheUOP’sworkingconceptappliedinthispaperisbasedonthepreviousworkof
theEuropeanInnovationPartnershiponSmartCitiesandCommunities(EIP–SCC).EIP–
SCChasdefinedsixActionClustersasitskeypriorityareas,including“IntegratedInfra‐
structuresandOpenData”.AgeneralobservationisthatUrbanPlatformsareaprerequi‐
sitetosupportfasttake‐upofsmartsolutionsincitiestoallowmanystakeholderstopar‐
ticipate.ItisalsoexpectedthatUrbanPlatformswouldhaveakeyroleintheintegration
ofthird‐partyvendorsolutions.
TheUrbanPlatformvisionofEIP–SCCisthatby2025,300millionEUcitizenswill
beservedbyplatformswithintheircitiesand,intheshortterm,acceleratetheadoption
ofUrbanPlatformsthroughaneasy‐to‐implementtemplateapproachandcross‐sector
collaboration.Meanwhile,thecloudplatformswillhavepickedupandthepublicsector
willhavestartedtomovetheirservicesintoAWS,GoogleorMicrosoftAzurecloudser‐
vices.
UrbanPlatformsareexpectedtoformacorebuildingblockbywhichcitiesbetter
managethecurrentexplosioninthevolumeofcitydataandmoreeasilysharethisdata
betweencityservicesinordertoprovidemeaningfulservicestotheirresidents.Itshould
benotedthoughthattheUPisnotasingleITsystemorserver.Itisacollectionofsmart
cityservicesthatcommunicateinternallyandexternallywithharmonisedAPIs.Theplat‐
formshouldbedistributedanddecoupledforvariousreasons.Thecityorganisational
complexitydoesnotsupporttheideaofasingle‐owner,single‐administrativeplatform
buttheoperationalmodelsshouldbebasedonagovernancemodelthattakesthisinto
account.
TheUrbanPlatforminitiativewassupportedbylaunchingamemorandumofun‐
derstandingthathad85signatories,includingbothcity‐andsmart‐city‐relatedvendors.
In2016,itwasestimatedthattheUPswerefragmented,haduncertaintiesonthedemand
sideandwerelackinginteroperabilityandcommonstandardsfromthesupplierside.At
themoment,thereisstillworkrequiredonalltheseareas.
TheUrbanPlatformconcepthasevolvedthroughseveralHorizon2020andEuro‐
peanRegionalDevelopmentFund(ERDF)‐fundedprojectssuchasbIoTope,mySMART‐
Life,Select4CitiesandSynchroniCity.Inmanyoftheprojects,theusageofUrbanPlat‐
formshasfocusedonbeinganIoTplatformwithdashboards.Thesupportofspatialdata
andlarge‐scaledatautilisationhavebeensomewhatlimitedandmanyofthepilotswere
experimentalplatformproductsthatwerenotreadynorintendedtobeinfull‐scalepro‐
ductionuse.Thelimitedvisionofthescopealsomissedtheopportunitytosupportcities
insomeoftheirnewdata‐relatedresponsibilities,suchasmaintainingInfrastructurefor
SpatialInformationinEurope(INSPIRE)–compliantdataservicesandprovidingsupport
forSustainableEnergyandClimateActionPlan(SECAP)–reporting.TheUrbanPlatform
shouldalsonotbeseenasamonolithic,singleservicebutasadistributedanddecoupled

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collectionofservicesthatcancomplementcities’existingdataplatforms.InbothHelsinki
andTallinn,akeyquestionishowcantheUrbanPlatformbuildontopoftheMicrosoft
Azuredatalakesanddatawarehousesthatbothcitieshavealreadyinvestedin.
2.4.UOPArchitecture
WhiletheUrbanOpenPlatformisanimplementationoftheEspressopreferencear‐
chitecture,basedontheH2020ESPRESSOproject,someareashaveevolvedoverthe
years.TheEspressoarchitecturewasseentodrivetowardsamonolithic,independenten‐
tityapproach,yetthemarkettrendsaremovingtowardsserverless,microserviceandna‐
noservicearchitecture.Themoderncloudarchitecturemakesithardertodescribetheen‐
tityasalayeredcapabilitymatrix.Eventhetypical“hamburgermodel”ofIoTplatforms
withsouthbound,datalakeandnorthboundismisleadinginmanyways,especiallyin
event‐drivenarchitecturethatIoTplatformsoftenare.Theplatformisexpectedtosupport
notonlydataacquisitionbutalsovarioustypesofdataprocessing.Dataisaggregated,
processed,manipulatedandextendedwithcontext.Bydefault,anydatacanhaveaspatial
reference—notonlyasorigindefinedwithcoordinatesbutalsowiththeabstractcity
modelfeatureasanorigin.Inaddition,real‐timedatacomesinmanyforms.Compared
tootherimplementationsofanurbandataplatform,theUOPplatformisnotexpectedto
directlysupportIoTsensorconnections.Itisassumedthatnowadayspracticallyalllarge‐
scaleinstallationswouldconnecttotheplatformthroughgatewaysthatthesensorscon‐
nectwithautomationfieldbusnetworkssuchasBACnetinbuildingautomation.
Theplannedhigh‐levelarchitectureoftheUrbanOpenPlatform,illustratedinFigure
2,followstheconventionsofpreviousprojectssuchasH2020ESPRESSO,H2020Synchro‐
niCityandH2020mySMARTLife.Specialattentionhasbeenputonscalabilityandrelia‐
bilityinlarge‐scaleproductionenvironments.ThenewdatastrategiesfromHelsinkiand
Tallinnhavecontributedtotheplanningandexistingenterprisearchitectureandpro‐
videdguidelinesonrelevantexistingtechnologiesandservicestoadoptandengage.In
bothcities,thecentraldataplatformsarebasedonMicrosoftAzure,whichnowisalsothe
basisoftheUrbanOpenPlatform.

Figure2.Componentdiagramforusecasebuildingautomationsystems.
Theopennessanddistributednatureoftheplatformcomesfromcomponentsbeing
definedforspecificfunctionality.Asanexample,thedatafusionstagecanbeimple‐
mentedasanETLprocess,adataintegrationtaskcreatedwithApacheCamel,datavirtu‐
alisationproductorsoftwarerobotics.ThebrokeringstageintheUOPisbasedonApache
Kafka,butitcouldbereplacedwithRabbitMQorcommercialbrokerorESBproducts.An
essentialfeatureoftheUOPconceptisthatthedatacataloguesanddataprocessingfunc‐
tionsareconnectedwiththebrokerandrouterstageandnotonthedatalake.Withthis

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approach,dataisprocessedwhileinmotion.Thisapproachsupportsreal‐timeanalytics
andvisualisationandsituationalawareness,butalsothedistributednatureoftheplat‐
formsincetherecanbeseveraldatabases,datamartsandlakesinsteadofonecentraldata
warehouseaccordingtotheneedsofeachbusinesscase.
Thismodularapproachalsoallowscitiestochoosevendorsandproductsthatthey
alreadyoperatewith.Theroleofopensourceisalsoaquestionthatrequiresfeasibility
analysis.IfthecityisalreadyoperatingonMicrosoftAzureorRedHatOpenStack,the
addedvalueofintroducingnewproductsdevelopedaspartofaninnovationprojectcan
bequestionableandthematurityofsuchproductscanevencauseadditionalrisks.
Duetothespatialnatureofpublicsectordataandthedigitaltwins,theprimaryAPI
fortheUOPwillbetheOGCAPIFeatures.
3.CaseStudyofTallinnandHelsinki
Thispaperappliesaqualitativecasestudymethodwheredataiscollectedfrompri‐
marysources(researchandinnovationprojectdeliverables,conductedbyauthorsthem‐
selves)andsecondarysources(previousresearchandinnovationdeliverables,suchasre‐
searchpapersandprojectreports).AcoremethodistovalidatetheproposedUOPcon‐
ceptempiricallywithreal‐lifeandreal‐timesensingusecasesimplementedinthecityof
Helsinki,withthepotentialtobereplicatedinTallinnandothercitiesglobally.
TallinnandHelsinki(twonorthernEuropecapitals)wereselectedforthefollowing
reasons:proximity(thetwocitiesarejust80kmapartbysea),high‐levelcommutingfre‐
quency(therewere8millionpassengersbetweenTallinnandHelsinkipre‐COVID‐19,
whereasEstonia’sentirepopulationisjust1.3million)anddigitalisation.(Finlandhasa
verystrongdigitalindustry,stronglyrootingfromNokia.Estonia,ontheotherhand,is
highlyappreciatedbecauseofitselectronicgovernment.)Economically,thecitiesarenot
the“inthesameleague”.Estoniaisapost‐Sovietcountrystilltryingtocatchupwhereas
Finlandisawell‐developedwesterncountry,makingthecitiesmoreheterogeneouswith
abiggerpotentialforascale‐up.
3.1.DataExchangePlatformfortheCross‐BorderRegion
Localgovernmentsaremoreandmoreexpectedtobeparticipatory,horizontaland
collaborativewiththehelpofdigitaltechnologies.Forexample,Lee&Lee[23]criticise
theprovider’sviewpointinprovisionofurbanserviceswhereorganisationstructuresare
constructedfortheconvenienceofadministration,insteadofcitizen,thusmakingtheser‐
viceprovisionvertical(e.g.,departmentsofmobilityandenvironmentandtheirdatabases
arefullydisconnected).Therefore,TallinnandHelsinki(andEstoniaandFinland,respec‐
tively)provideaninterestingcase,astheirpublicsectordatabasesareinterconnected(in
thecaseofEstonia)orthereareplanstoconnectthem(inthecaseofFinland),which
makesinterandintracitydataexchangepossible.Itshouldbenotedthatachievingthis
assumesachangeinorganisations’managementpracticesandlegalset‐ups.Whileprac‐
ticallycomplex,especiallywhenconsideringsocialandpoliticalresistancetochange,itis
notimpossible.
Thoughinitiatedtop‐down,Estoniaasacountryisaninterestingexampleofthehor‐
izontalexchangeofdata,asthereisclosetofullinteroperabilitybetweenpublicsector
databasesviathedata‐exchangelayerX‐Road,bothwithindepartmentsinonecityand
acrossallnationalcities.Forexample,thenationalpopulationregistry(whichstemsfrom
thepopulationregistryofTallinn)isfullyintegratedwithallcitiesandothergovernment
actorsinEstonia.Therefore,citiescannotkeeptheirownpopulationregistries,asthereis
onelivedatabaseforallresidentsinEstonia,andeverymunicipalitymustintegratetheir
servicesbasedonthiscentralregistry(e.g.,registrationofnewordepartingresidents).It
isimportanttonotethatX‐Roadisnotextraordinarybecauseofitstechnologicalfeatures
(thereareplentyofsimilar‐logicenterpriseservicebusplatformsavailable)butmainly
becauseitisacaseofsuccessfulimplementation,bothorganisationallyandlegally.Essen‐
tially,itisarule‐basedapproach,andalltheserulesneedtobedefined(e.g.,whocan

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makeinquiriestothepopulationandtheotherthousanddatabasesandhow).Inthisper‐
spective,X‐Roadisusedasalighthousesolutionthroughoutthearticle,indicatinghow
thetwincities(HelsinkiandTallinn)couldconceptuallybenefitfromit[2,24]).TheX‐
RoadplatformisshowninFigure3.Briefly,inEstonia,over3000governmentsector(in‐
cludingallcities)databasesareinterlinkedviatheInternetusingthetransportlayer.
InspiredbyX‐Road(http://epl.delfi.ee/news/eesti/soome‐votab‐kasutusele‐meie‐x‐
tee‐susteemi?id=67359844,accessedon6January2022(inEstonian)),Finlandisalsoim‐
plementingitsdataexchangelayer,withbothcountriesagreeingtodevelopafederated
solution.In2017,thisresultedintheformationofajointorganisation,TheNordicInstitute
forInteroperabilitySolutions,whichhasthemissiontodevelopfederatede‐governance
solutionsconnectingEstonianX‐RoadtechnologywithitsFinnishcounterpart(Palve‐
luväylä).Thefirstpilotsbasedonthesefederatedtwo‐countrydataexchangelayersare
liveandfocusontheexchangeofbusinessandpopulationdata(seespecificusecases:
PopulationRegistryandBusinessregistry).Inaddition,therearealsousecaseofsolutions
thatworkonlyinonecity/country,e.g.,SmartMetersinEstoniaandEnvironmentalSer‐
vicesinHelsinki.

Figure3.TheX‐Roadplatform.Source:EstonianInformationSystemAuthority.
Ifthefederationofdataexchangelayersbetweentwocountries(seeFigure4)was
fullyimplemented,thiswouldofferanexperimentalsettingforajointcross‐bordere‐ser‐
vicebetweenthetwocapitals(italsoappliestoallcitiesinEstoniaandFinland).Cur‐
rently,thetwocitiesstilloperateasdigitalislandsbutthefederationofdataexchange
platformscouldeffectivelyleadtojointdigitalservicesbasedonreal‐timedatarequests
fromurbanandgovernmentaldatabases,hencealsobenefitingthecommutersandmacro‐
regions.Continuingwiththeexampleofpopulationregistry,apersonmovingfromTal‐
linntoFinlandcouldautomaticallymeanerasingresidencestatusinTallinnandtransfer‐
ringittoHelsinki.Again,theimplementationoffederateddataexchangelayersisnot
onlyatechnologicalchallenge,butthemainassumptionisthatthisispoliticallydesirable
(multiplepartiesagreeonhowdatacanbeexchangedandaremotivatedtodoso,thatis,
createnovelinstitutions).

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
Figure4.Federationofdataplatforms.Source:EstonianInformationSystemAuthority.
Thenextstepforsmartcitiescouldbetheintegrationofvarioussensordatabyim‐
plementinganopenandinteroperableplatformforconnectedsensorsorarangeofenti‐
ties.Thatis,inadditionto“citizen‐based”databases,therecouldbeinterconnectedregis‐
tries,bothpublicandprivate,forentitiessuchasunitymeters(gas,electricity,water),
vehicles(cars,buses,trains,etc.),homeappliances,heating,lightingandwastemanage‐
mentsystems,weatherforecastdata,etc.InEstonia,thereisafirststeptowardsthis,
namelytheEstfeedplatform,whichconnectscloseto600,000electricityusers,withmost
end‐usersabletotracetheirenergyconsumptionviaconnectedmetersovertheInternet
[25].Thisplatform,runningonX‐Road,linksdatasourcesandapplicationsandprovides
auserinterfaceforcustomerstoseeandmanagetheirenergyconsumptiondataand
rights.Forperfectlyfederatedsmartcities,suchafederationcouldbethenextstep,after
havingintegratedthepublicregistries.
3.2.AISolutionsfortheCross‐BorderRegion
Conceptually,federateddataplatformscouldautomateprocessesradicallywiththe
applicationofartificialintelligence.Theterm“Kratt”(magicalcreatureinoldEstonian
mythology,atreasurebearer)wasintroducedinEstoniainreferencetopracticalapplica‐
tionsbasedonartificialintelligencetechnologies(inthenarrowmeaningofartificialin‐
telligence)performingaspecificfunction.ForthevisonofKratttobecomereality,several
technologicalchallengesneedtoberesolvedasmentionedinKratt’svisionpaper
(https://www.kratid.ee/visionpaper,accessedon6January2022).Inthecontextofthispa‐
per,mostrelevantareissueswithinteroperability.Atthisstage,itisnotevenclearwhat
willbethenecessaryinteroperabilityframework.Securedataexchangeprotocolandgov‐
ernancewillbenecessarytojointheAIapplicationsandvirtualassistants’functionto‐
getherandtransparentlybetweengovernmentagencies,betweenprivateandpublicsec‐
torsandalsoacrossborders.Therearealsolegacyissuesasthedevelopmenthastobe
builttakingintoaccounttheexistingEstoniangovernmentalinteroperabilityframework
andX‐Roaddataexchangefoundations.
Anotheraspectthatneedstobedevelopedisaso‐calleddigitaltwinofpeople.Itis
importanttonotethatthistwinwouldnotduplicateallofpeople’sdatabutratherwould
holddataonconsents,interactionsandotherpreferencesforpublicservicesthatpeople
havemadeasthebasisformachine‐to‐machineinteractionandqueries.Thefutureofdig‐
italgovernmentthatisinteroperablewillbesubjecttoconstantchangeasbotsoragents
willbeaddedanditerated.So,theunderlyingdatasetsandITsystemshavetobeflexible
andreadyforconstantfurtherdevelopment.Thatvisioninmind,itwouldmakesenseto

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startwithamicroservice‐basedset‐upofITsystemstoensureflexibilityofdevelopment
andfast‐scalingcapability.Evenmoreimportantisthedevelopmentofadataexchange
basedonamessagingroomset‐up,whichcouldbecomeanadditiontotheEstoniancur‐
rentX‐Roadbaseddataexchange.AtthisstageitisunclearwhetherX‐Road’ssynchro‐
nousconnectionsaresufficienttosupportparallelworkingofmanyAIapplicationsat
once.
Estoniahasmadeanexcellentefforttomakedifferentdatasetsopenlyavailableto
encouragethedevelopmentofcommercialornon‐profitdigitalsolutions,conductre‐
searchormakedata‐drivendecisions.Asof1April2021,therewere793datasetsavailable
ontheEstonianopendataportal(https://avaandmed.eesti.ee/,accessedon6January
2022).ForthesuccessfuldevelopmentofKrattAI,theavailabilityandqualityofopendata
willplayasignificantrole.Itisunclearhowmuchdataisrequiredtotrainthemachine
learningalgorithm,butdependingonthecomplexityoftheproblem,itisrealisticthat
thousandsofdatapointsmaybeneeded.Inthecaseofmachinelearning,itisaprerequi‐
sitethatthetrainingdataisnotbiasedtowardscertaindecisions,isofhighqualityand
completeandismarkedaccordingly.WiththeUOP,valueinthecontextofthedatawill
beimproved.Nodataisperfectbutifitcomeswithinstructionsaboutusability,itcanstill
addvalue.
InFinland,theconceptAurorahasmanycommondenominatorswithKratt’sinitia‐
tiveinEstonia.Thereexistsaninteresttocollaboratebetweenthesetwodevelopments—
atleastexchangingideasandexperiences,butalso,ifpossible,developingjointtechnical
solutions.ThatwouldcreatethepotentialforinteroperabilitybetweenEstonianandFinn‐
ishnationalAIbasede‐services.Thus,thevirtualassistantswouldoperateacrossborders
andhelptocreateEstonianandFinnishcommondigitalspace.Estonia–Finlandunited
digitalspaceisalreadyoneofEstonia’sdigitalpolicyprioritiesandwouldcontinueinthis
wayevenintimesofAI,especiallyinthecontextthatFinlandandEstonia’sdataexchange
layerswereconnectedtooneanotherinFebruary2018.Additionally,in2019,thenational
businessregistersandtaxboardsinEstoniaandFinlandweremovingtowardscoopera‐
tionthatwouldallowtheagenciestoexchangedatainamoreaccurateandefficientway
byusingX‐RoadTrustFederation.InEuropeanenergycooperation,digitalsolutionsare
beingdevelopedtobuildsmartgridsandtoenabletheeffectiveuseofrenewableenergy.
Newcross‐borderservicesarebeingdevelopedinboththepublicandprivatesectors
(https://sites.utu.fi/bre/estonia‐and‐finland‐digital‐forerunners‐in‐cross‐border‐coopera‐
tion/,accessedon6January2022).
3.3.HelsinkiReal‐LifeUOPUseCasesintheBetaStage
TheworkingconceptoftheUOPisdemonstratedviareal‐lifeusecasesthathave
beenselectedtosupportthecurrentinterestsofthecities.Thebetastageusecaseshave
beendevelopedbasedonrealdatafromtheHelsinkicityoperationsandhavebeense‐
lectedbasedontheavailabilityofdatafromvarioussensors.Itshouldbenotedthatnot
allthedataisopen.Inthenextstage,datasourcesfromTallinnareplannedtobedefined
andutilisedasfeasible.Inthebetastage,nodashboards,applicationsandserviceshave
beencreatedtoutilisethedata.
TheconductedcaseshelptovalidatetheUOPworkingconceptandalsohelpthefirst
pilotcitytohavemorestructuredaccesstodifferentsensordatainthevariedfieldsof
governance,energy,mobilityandbuiltenvironment.
4.DiscussionandConclusions
ThispaperintroducedavisionoftheUrbanOpenPlatformthatgoesbeyondtypical
IoTplatformswithadashboard.TheUOPasaconceptalsoinvolvesagovernanceaspect
ofdataplatforms,ascitiesasinstitutionsareverycomplexwhere“one‐size‐fits‐all”solu‐
tionsdonotautomaticallyapply.Inaddition,wealsobringtothediscussionthefree
roamingofdatabetweenkeystakeholdersofacitythatcanbeothercities,companies,
universities,governmentagencies,etc.Conceptually,anUOPcanexchangedataacross

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differentstakeholders,similartohowX‐Roaddataexchangelayerworksinthecaseof
Estonia.However,freeurbandataroaminginnotasimpletaskbutatruewickedproblem
whereoperational,technical,legalandalsoethicalchallengesneedtobesolved.Inaddi‐
tion,citieswithoutstrongdatagovernancepoliciestendtobealsolockedintospecific
contractsandvendors.Moreoftenthannot,citieshaveaccessbarrierstothedataowned
bydifferentcitydepartmentsthemselves.Forexample,publictransportusageorcity
streetconstructiondataisoftennotaccessibletocitycivilservantsinrealtime,even
withinonecity.Therefore,weneedtostartwithsmallstepstomakedataroamingpossi‐
ble.
InthecaseoftheUOP,weanalysedthedata‐roamingpotentialbetweentwonearby
butheterogeneousEuropeancities,HelsinkiandTallinn.First,wemappedservicesthat
arecurrentlyavailablebetweenthetwocitiesduetothesimilaritiesofdataexchangelay‐
ersandthepotentialtofederatethem.Forexample,populationregistriesandbusiness
registriescanexchangedatainrealtimeandthereisavalidconsentprocedureforthisvia
federatedX‐Roads.However,inordertotesttheconceptwithreal‐lifesensordatabased
ontheinterestsandusecasesofthecityofHelsinkiinthebetastage.Therefore,theUOP
asaconceptwasvalidatedviaintegrationof10usecasesthatpullreal‐timedatafrom
varioussensorsinthecityenvironment.This,simplyput,showcasesthatthedifferent
institutionalbarrierscanbeovercomeforbetterdataroaminginthecaseofIoT.
SmartcityisoftenlinkedtotheInternetofThingsandsensors[26,27],whereasplat‐
formshavebeendevelopedthatenabletoconnectdifferentthematicaldatabases[28],alt‐
houghtheseconceptsoftendonotcommunicateandsyncwitheachother.Inthisper‐
spective,severalauthors[26,27]aimtodevelopjointprotocolsandarchitectureforlinking
varioussensorstotheInternet.Thisprovidestheabilitytoremotelymanagedevicesbased
onreal‐timedatacomingfromsensors[27]thathavebecomecontributorsoflarge
amountsofdata[29,30].Veryoften,citiesareclaimedtobesmartcitieswhentheyopen
upmoredata,includingdatafromwirelesssensornetworks[30].Nevertheless,thecity
innovatorsshouldnotonlyfocusonICTdataorinfrastructurebutonhowtocreatevalue
forcitizens.Conceptually,thecombinationofpowerfulandsmallmicroprocessors,smart
mobiledevices,low‐costsensing,dataanalytics,cloudtechnologiesandadvancedcon‐
nectivitysetsaconceptualframeworkforautomaticallyconnectingentities[31].
Furthermore,averyimportantlessonlearntisthatasuccessfulsmartcityimplemen‐
tationisalessspecificsoftwareproductorvendorspecificbutaddressesactualurban
challenges.Therefore,varioussoftwaresolutionsforIoTinsmartcities,suchasKaftaor
FMEETappliedinourusecases,shouldbetakenasapotentialtoolboxthatisopenfor
othersolutions.Ingeneral,wehaveseenfrompreviousresearchthatclosedIoTplatforms
tendnottomainstream,probablyduetotechnologicalandoperationallock‐ins.There‐
fore,morefocusshouldbeputondistributedconcepts,suchasX‐Roadanddatamesh.
Forfutureempiricalresearch,morefocuscouldbeputonhowcross‐bordercitiescan
offerjointservicesviaanUOP.ThecitiesofTallinnandHelsinkiareverydifferenteco‐
nomicallyand,therefore,ajointplatformforsmartcityservicescaneffectivelyserveasa
knowledgetransfermechanismfromamoreadvancedregion(Helsinki)toadeveloping
region(Tallinn).Astrongcommonelementofbothcitiesistheirstrongdigitalinfrastruc‐
tureandpotentialforinteroperabilityofservices.
Thekeypointtounderstandawinningsmartcityistounderstandthatthisisnota
one‐citynorone‐countrygame[8].Nomatterhowbigacity(Tokyo,SaoPaulo,etc.)is,
anylocalgovernmentistoosmalltocreatearealecosystemofcutting‐edgeagileand
adaptivegovernancesolutions(predictiveanalytics,InternetofThingsandbigdatatech‐
nologies).Thefirstdeploymentshaveledtoinflexible“smartcitiesinabox”or“smart
countriesinabox”whichareageingfast,andfromwhichsolutionsdonotscaleelse‐
where.Thereisaneedtostartfromsimpleandwidespreadurbanservicesthroughacol‐
laborativejointcross‐border,hands‐oneffort.Standardisationisalsothekeytocross‐bor‐
derurbanservices.Therealthreatisthatiflocalmunicipalitiesdonotmanagetoinnovate
fromthebottomupjointlywithneighbouringcities(bothnationalandinternational),then

Appl.Sci.2022,12,70013of14
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allcross‐bordersolutionwillbeenforcedtop‐downoraggressivelylinkedtoglobalbusi‐
nessvendors.
AuthorContributions:Conceptualization,R.‐M.S.,T.R.,andH.P.methodology,R.‐M.S.andT.R.;
writing—originaldraftpreparation,R.‐M.S.,T.R,andH.P.;writing—reviewandediting,R.‐M.S.,
T.R.,andH.P.;visualization,T.R.Allauthorshavereadandagreedtothepublishedversionofthe
manuscript.
Funding:ThisresearchhasbeensupportedbytheEuropeanCommissionthroughtheH2020project
FinestTwins(grantNo.856602).
InstitutionalReviewBoardStatement:Notapplicable.
InformedConsentStatement:Notapplicable.
ConflictsofInterest:Theauthorsdeclarenoconflictofinterest.
References
1. Infranca,J.J.;Miller,S.R.UrbanDataandthePlatformCity.InTheCambridgeHandbookoftheLawoftheSharingEconomy;Cam‐
bridgeUniversityPress:Cambridge,UK,2018;pp.192–202.https://doi.org/10.1017/9781108255882.015.
2. Soe,R.‐M.SmartTwinCitiesviaUrbanOperatingSystem.InProceedingsofthe10thInternationalConferenceonTheoryand
PracticeofElectronicGovernance,ICEGOV’17,NewDelhi,India,7–9March2017;pp.391–400.
https://doi.org/10.1145/3047273.3047322.
3. Eicker,U.;Weiler,V.;Schumacher,J.;Braun,R.Onthedesignofanurbandataandmodelingplatformanditsapplicationto
urbandistrictanalyses.EnergyBuild.2020,217,109954.https://doi.org/10.1016/j.enbuild.2020.109954.
4. Hernández,J.L.;García,R.;Schonowski,J.;Atlan,D.;Chanson,G.;Ruohomäki,T.InteroperableOpenSpecificationsFrame‐
workfortheImplementationofStandardizedUrbanPlatforms.Sensors2020,20,2402.https://doi.org/10.3390/s20082402.
5. Badidi,E.;Maheswaran,M.Towardsaplatformforurbandatamanagement,integrationandprocessing.InProceedingsofthe
3rdInternationalConferenceonInternetofThings,BigDataandSecurity—IoTBDS2018,Funchal,Madeira,Portugal,19–21
March2018;pp.299–306.https://doi.org/10.5220/0006789602990306.
6. Cheng,B.;Longo,S.;Cirillo,F.;Bauer,M.;Kovacs,E.BuildingaBigDataPlatformforSmartCities:ExperienceandLessons
fromSantander.InProceedingsoftheIEEE2015InternationalCongressonBigData,NewYork,NY,USA,27June–2July2015,
pp.592–599.https://doi.org/10.1109/BigDataCongress.2015.91.
7. Lee,A.;Mackenzie,A.;Smith,G.J.D.;Box,P.MappingPlatformUrbanism:ChartingtheNuanceofthePlatformPivot.Urban
Plan.2020,5,116–128.https://doi.org/10.17645/UP.V5I1.2545.
8. Soe,R.‐M.FINESTTwins:Platformforcross‐bordersmartcitysolutions.InProceedingsofthe18thAnnualInternationalCon‐
ferenceonDigitalGovernmentResearch,StatenIsland,NY,USA,7–9June2017;pp.352–357.
https://doi.org/10.1145/3085228.3085287.
9. Ratti,C.;Nabian,N.VirtualSpace,TheCitytoCome.InInnovationPerspectivesforthe21stCentury;BBVA:Bilbao,Spain,2010;
pp.383–397.
10. Allen,B.;Tamindael,L.E.;Bickerton,S.H.;Cho,W.Doescitizencoproductionleadtobetterurbanservicesinsmartcitiespro‐
jects?Anempiricalstudyone‐participationinamobilebigdataplatform.Gov.Inf.Q.2020,37,101412.
https://doi.org/10.1016/j.giq.2019.101412.
11. Velsberg,O.;Westergren,U.H.;Jonsson,K.Exploringsmartnessinpublicsectorinnovation‐creatingsmartpublicserviceswith
theInternetofThings.Eur.J.Inf.Syst.2020,29,350–368.https://doi.org/10.1080/0960085X.2020.1761272.
12. Bibri,S.E.TheIoTforsmartsustainablecitiesofthefuture:Ananalyticalframeworkforsensor‐basedbigdataapplicationsfor
environmentalsustainability.Sustain.CitiesSoc.2018,38,230–253.https://doi.org/10.1016/j.scs.2017.12.034.
13. Mohanty,S.P.;Choppali,U.;Kougianos,E.Everythingyouwantedtoknowaboutsmartcities:TheInternetofthingsisthe
backbone.IEEEConsum.Electron.Mag.2016,5,60–70.https://doi.org/10.1109/mce.2016.2556879.
14. Khajenasiri,I.;Estebsari,A.;Verhelst,M.;Gielen,G.AReviewonInternetofThingsSolutionsforIntelligentEnergyControlin
BuildingsforSmartCityApplications.EnergyProcedia2017,111,770–779.https://doi.org/10.1016/j.egypro.2017.03.239.
15. Krylovskiy,A.;Jahn,M.;Patti,E.DesigningaSmartCityInternetofThingsPlatformwithMicroserviceArchitecture.InPro‐
ceedingsofthe3rdInternationalConferenceonFutureInternetofThingsandCloud,FiCloud2015,Rome,Italy,24–26August
2015;pp.25–30.https://doi.org/10.1109/FiCloud.2015.55.
16. Talari,S.;Shafie‐Khah,M.;Siano,P.;Loia,V.;Tommasetti,A.;Catalão,J.P.S.Areviewofsmartcitiesbasedontheinternetof
thingsconcept.Energies2017,10,1–23.https://doi.org/10.3390/en10040421.
17. Barns,S.Re‐engineeringtheCity:PlatformEcosystemsandtheCaptureofUrbanBigData.Front.Sustain.Cities2020,2,1–8.
https://doi.org/10.3389/frsc.2020.00032.
18. Khan,F.H.AnExploratoryResearchonUrbanDataPlatformBusinessandOperationalModel:AchievingCircularEconomy
ofDatawithSupplyChainMechanism.Master’sThesis,ÅboAkademiUniversity,Turku,Finaland,2018.Availableonline:
https://www.doria.fi/handle/10024/165066(accessedon6January2022).

Appl.Sci.2022,12,70014of14

19. Conway,M.E.Howdocommitteesinvent?Datamation1968,14,28–31.
20. Ford,N.;Parsons,R.;Kua,P.BuildingEvolutionaryArchitectures;O’ʹReilly:Newton,MA,USA,2017;ISBN978‐1‐491‐98636‐3.
21. Meierhofer,J.;Stadelmann,T.;Cieliebak,M.DataProducts.InAppliedDataScience;BraschlerM.,StadelmannT.,StockingerK.,
Eds.;Springer:Cham,Switzerland,2019.https://doi.org/10.1007/978‐3‐030‐11821‐1_4.
22. Kotler,P.;Armstrong,G.PrinciplesofMarketing,10thed.;PrenticeHallCollegeDivision:Hoboken,NJ,USA,2004.
23. Lee,J.;Lee,H.Developingandvalidatingacitizen‐centrictypologyforsmartcityservices.Gov.Inf.Q.2014,31,SUPPL.1,S93–
S105.doi:10.1016/j.giq.2014.01.010.
24. Soe,R.‐M.;Drechsler,W.Agilelocalgovernments:Experimentationbeforeimplementation.Gov.Inf.Q.2018,35,323–335,doi:
10.1016/j.giq.2017.11.010.
25. Soe,R.‐M.Data‐BasedEnergyProvisionforSmartCities.InCommunicationsinComputerandInformationScience;Springer:Berlin,
Germany,2017;Volume745,pp.319–328.https://doi.org/10.1007/978‐3‐319‐69784‐0_27.
26. Petrolo,R.;Loscrì,V.;Mitton,N.Towardsasmartcitybasedoncloudofthings,asurveyonthesmartcityvisionandparadigms.
Trans.Emerg.Telecommun.Technol.2017,28,e2931.https://doi.org/10.1002/ett.2931.
27. KimT.H.;Ramos,C.;Mohammed,S.SmartCityandIoT.FutureGener.Comput.Syst.2017,76,159–162.
https://doi.org/10.1016/j.future.2017.03.034.
28. Hashem,I.A.T.;Chang,V.;Anuar,N.B.;Adewole,K.;Yaqoob,I.;Gani,A.;Ahmed,E.;Chiroma,H.Theroleofbigdatainsmart
city.Int.J.Inf.Manag.2016,36,748–758.https://doi.org/10.1016/j.ijinfomgt.2016.05.002.
29. Gaur,A.;Scotney,B.;Parr,G.;McClean,S.SmartcityarchitectureanditsapplicationsbasedonIoT.ProcediaComput.Sci.2015,
52,1089–1094.https://doi.org/10.1016/j.procs.2015.05.122.
30. Santos,H.;Furtado,V.;Pinheiro,P.;McGuinness,D.L.ContextualDataCollectionforSmartCities.arXiv2017,arXiv:1704.01802.
Availableonline:http://arxiv.org/abs/1704.01802(accessedon6January2022).
31. Hammoudeh,M.;Arioua,M.SensorsandActuatorsinSmartCities.J.Sens.ActuatorNetw.2018,7,8.
https://doi.org/10.3390/jsan7010008.