Internet of Things (Iot): a Vision, Architectural Elements, and Future Directions

FutureGenerationComputerSystems29(2016)1645–1660

InternetofThings(IoT):Perimeter Access Control, Liquid Presence

Muhamad Yoga Santosoa

aDepartmentofCyber Police,TheUniversityof Youngsan,Ysangsan-si,South Korea

highlights

•Access control to restricted areas and detection of people in non-authorized areas.

•Liquid detection in data centers, warehouses and sensitive building grounds to prevent break downs and corrosion.

a r t i c lei n foabstract

Articlehistory:

Received 8 July 2016Received in revisedform 22 August2016

Accepted15September2016

Available online 29September2016

Keywords: Internet of Things

Perimeter Access Control

Liquid Presence

Keep access points to a minimum and make sure the boundary between public and private areas of your building is secure and clearly signed. Invest in good quality access controls such as magnetic swipe identification cards or 'proximity' cards which are readable from a short distance.

1.Introduction

Thenextwaveintheeraofcomputingwillbeoutsidetherealm ofthetraditionaldesktop.IntheInternetofThings(IoT)paradigm, manyoftheobjectsthatsurrounduswillbeonthenetworkinone formoranother.RadioFrequencyIDentification(RFID)andsensor networktechnologieswillrisetomeetthisnewchallenge,inwhich informationandcommunicationsystemsareinvisiblyembeddedin the environment around us. This results in the generation of enormous amounts of data which have to be stored, processed and presented in a seamless, efficient, and easily interpretable form.Thismodelwillconsistofservicesthatarecommoditiesand delivered in a manner similar to traditional commodities.Cloud

computing can provide the virtual infrastructure for such utility computingwhichintegratesmonitoringdevices,storagedevices, analyticstools,visualizationplatformsandclientdelivery.Thecost based model that Cloud computing offers will enableend-to-end serviceprovisioningforbusinessesanduserstoaccessapplications ondemandfromanywhere.

Smart connectivity with existing networks and context-aware computation using network resources is an indispensable partof IoT.WiththegrowingpresenceofWiFiand4G-LTEwirelessInter- netaccess,theevolutiontowardsubiquitousinformationandcom- municationnetworksisalreadyevident.However,fortheInternet ofThingsvisiontosuccessfullyemerge,thecomputingparadigm will need to go beyond traditional mobile computing scenarios that use smart phones and portables, and evolve into connect- ingeverydayexistingobjectsandembeddingintelligenceintoour environment. For technology to disappear from the conscious- ness of the user, the Internet of Things demands: (1) a shared understanding of the situation of its users and their appliances,

1646J.Gubbietal./FutureGenerationComputerSystems29(2013)1645–1660

(2)softwarearchitecturesandpervasivecommunicationnetworks toprocessandconveythecontextualinformationtowhereitisrel- evant,and(3)theanalyticstoolsintheInternetofThingsthataim forautonomousandsmartbehavior.Withthesethreefundamental groundsinplace,smartconnectivityandcontext-awarecomputa- tioncanbeaccomplished.

The term Internet of Things was first coined by Kevin Ashton in1999inthecontextofsupplychainmanagement[1].However, in the past decade, the definition has been more inclusive cover- ingwiderangeofapplicationslikehealthcare,utilities,transport, etc. [2]. Although the definition of ‘Things’ has changed as tech- nologyevolved,themaingoalofmakingacomputersenseinfor-mation without the aid of human intervention remains thesame. A radical evolution of the current Internet into a Network of in- terconnected objects that not only harvests information from the environment(sensing)andinteractswiththephysicalworld(actu- ation/command/control),butalsousesexistingInternetstandards toprovideservicesforinformationtransfer,analytics,applications,andcommunications.Fueledbytheprevalenceofdevicesenabled by open wireless technology such as Bluetooth,radiofrequencyidentification(RFID),Wi-Fi,andtelephonicdataservicesaswellas embeddedsensorandactuatornodes,IoThassteppedoutofitsin- fancyandisonthevergeoftransformingthecurrentstaticInternet intoafullyintegratedFutureInternet[3].TheInternetrevolution led to the interconnection between people at an unprecedented scaleandpace.Thenextrevolutionwillbetheinterconnectionbe- tweenobjectstocreateasmartenvironment.Onlyin2011didthe number of interconnected devices on the planet overtake the ac- tualnumberofpeople.Currentlythereare9billioninterconnected devices and it is expected to reach 24 billion devices by 2020. AccordingtotheGSMA,thisamountsto$1.3trillionrevenueop- portunities for mobile network operators alone spanningvertical segmentssuchashealth,automotive,utilitiesandconsumerelec- tronics.Aschematicoftheinterconnectionofobjectsisdepictedin Fig.1,wheretheapplicationdomainsarechosenbasedonthescale oftheimpactofthedatagenerated.Theusersspanfromindividual tonationallevelorganizationsaddressingwiderangingissues.

This paper presents the current trends in IoT research propelledbyapplicationsandtheneedforconvergenceinseveral interdisciplinarytechnologies.Specifically,inSection2,wepresent the overall IoT vision and the technologies that will achieve it followed by some common definitions in the area along with sometrendsandtaxonomyofIoTinSection3.Wediscussseveral applicationdomainsinIoTwithanewapproachindefiningthem in Section4and Section5provides our Cloud centric IoTvision.

A case study of data analytics on the Aneka/Azure cloud platform is given in Section6and we conclude with discussions on open challenges and future trends in Section7.

2.Ubiquitous computing in the nextdecade

The effort by researchers to create a human-to-human inter- face through technology in the late 1980s resulted in the creation oftheubiquitouscomputingdiscipline,whoseobjectiveistoem-bedtechnologyintothebackgroundofeverydaylife.Currently,we areinthepost-PCerawheresmartphonesandotherhandheldde- vicesarechangingourenvironmentbymakingitmoreinteractive aswellasinformative.MarkWeiser,theforefatherofUbiquitous Computing (ubicomp), defined a smart environment [4] as ‘‘the physicalworldthatisrichlyandinvisiblyinterwovenwithsensors,actuators,displays,andcomputationalelements,embeddedseam- lesslyintheeverydayobjectsofourlives,andconnectedthrough acontinuousnetwork’’.

The creation of the Internet has marked a foremost milestone towards achieving ubicomp’s vision which enables individual devices to communicate with any other device in the world. The

inter-networking reveals the potential of a seemingly endless amountofdistributedcomputingresourcesandstorageownedby variousowners.

In contrast to Weiser’s Calm computing approach, Rogers proposes a human centric ubicomp which makes use of human creativityinexploitingtheenvironmentandextendingtheircapa- bilities[5].Heproposesadomainspecificubicompsolutionwhen he says—‘‘In terms of who should benefit, it is useful to think of how ubicomp technologies can be developed not for the Sal’s of the world, but for particular domains that can be set up and cus- tomizedbyanindividualfirmororganization,suchasforagricul- turalproduction,environmentalrestorationorretailing’’.

Caceres and Friday [6] discuss the progress, opportunities and challenges during the 20 year anniversary of ubicomp. They discuss the building blocks of ubicomp and the characteristics of the system to adapt to the changing world. More importantly, they identify two critical technologies for growing the ubicomp infrastructure—Cloud Computing and the Internet of Things.

Theadvancementsandconvergenceofmicro-electro-mechan- ical systems (MEMS) technology, wireless communications, and digital electronics has resulted in the development of miniature devices having the ability to sense, compute, and communicate wirelesslyinshortdistances.Theseminiaturedevicescallednodes interconnect to form a wireless sensor networks (WSN) and find wide ranging applications in environmental monitoring, infras- tructuremonitoring,trafficmonitoring,retail,etc.[7].Thishasthe abilitytoprovideaubiquitoussensingcapabilitywhichiscritical inrealizingtheoverallvisionofubicompasoutlinedbyWeiser[4]. FortherealizationofacompleteIoTvision,efficient,secure,scal- ableandmarketorientedcomputingandstorageresourcingises- sential.Cloudcomputing[6]isthemostrecentparadigmtoemerge which promises reliable services delivered through next genera- tion data centers that are based on virtualized storage technolo- gies. This platform acts as a receiver of data from the ubiquitous sensors; as a computer to analyze and interpret the data; as well as providing the user with easy to understand web basedvisual- ization.Theubiquitoussensingandprocessingworksintheback- ground,hiddenfromtheuser.

This novel integrated Sensor–Actuator–Internet framework shallformthecoretechnologyaroundwhichasmartenvironment will be shaped: information generated will be shared across di- verseplatformsandapplications,todevelopacommonoperating picture (COP) of an environment, where control of certain unre- stricted‘Things’ismadepossible.Aswemovefromwww(static pagesweb)toweb2(socialnetworkingweb)toweb3(ubiquitous computingweb),theneedfordata-on-demandusingsophisticated intuitivequeriesincreases.Totakefulladvantageoftheavailable Internettechnology,thereisaneedtodeploylarge-scale,platform- independent,wirelesssensornetworkinfrastructurethatincludes datamanagementandprocessing,actuationandanalytics.Cloud computingpromiseshighreliability,scalabilityandautonomyto provideubiquitousaccess,dynamicresourcediscoveryandcom- posability required for the next generation Internet of Thingsap- plications. Consumers will be able to choose the service level by changingtheQualityofServiceparameters.

3.Definitions, trends andelements

3.1.Definitions

As identified by Atzori et al. [8], Internet of Things can be re- alized in three paradigms—internet-oriented (middleware), things oriented (sensors) and semantic-oriented (knowledge). Although this type of delineation is required due to the interdisciplinary na- ture of the subject, the usefulness of IoT can be unleashed only in an application domain where the three paradigms intersect.

The RFID group defines the Internet of Things as –

J.Gubbietal./FutureGenerationComputerSystems29(2013)1645–16601647

Fig. 1. Internet of Things schematic showing the end users and application areas based on data.

•The worldwide network of interconnected objects uniquely addressablebasedonstandardcommunicationprotocols.

AccordingtoClusterofEuropeanresearchprojectsontheInternet of Things [2]–

•‘Things’ are active participants in business, information and social processes where they are enabled to interact and com- municateamongthemselvesandwiththeenvironmentbyex- changingdataandinformationsensedabouttheenvironment,whilereactingautonomouslytothereal/physicalworldevents andinfluencingitbyrunningprocessesthattriggeractionsand createserviceswithorwithoutdirecthumanintervention.

According to Forrester [9], a smart environment –

•Uses information and communications technologies to make the critical infrastructure components and services of a city’sadministration,education,healthcare,publicsafety,real estate,transportationandutilitiesmoreaware,interactiveandefficient.

Inourdefinition,wemakethedefinitionmoreusercentricanddo not restrict it to any standard communication protocol. This will allowlong-lastingapplicationstobedevelopedanddeployedusingthe available state-of-the-art protocols at any given point intime. OurdefinitionoftheInternetofThingsforsmartenvironmentsis

–

•Interconnectionofsensingandactuatingdevicesprovidingthe ability to share information across platforms through a uni- fied framework, developing a common operating picture for enablinginnovativeapplications.Thisisachievedbyseamless ubiquitoussensing,dataanalyticsandinformationrepresenta- tionwithCloudcomputingastheunifyingframework.

3.2.Trends

Internet of Things has been identified as one oftheemergingtechnologiesinITasnotedinGartner’sITHypeCycle(seeFig.2).AHypeCycle[10]isawaytorepresenttheemergence,adoption,maturity,andimpactonapplicationsofspecifictechnologies.IthasbeenforecastedthatIoTwilltake5–10yearsformarketadoption.Thepopularityofdifferentparadigmsvarieswithtime.Thewebsearchpopularity,asmeasuredbytheGooglesearchtrendsduringthe last 10 years for the terms Internet of Things, WirelessSensor

NetworksandUbiquitousComputingareshowninFig.3[11].As itcanbeseen,sinceIoThascomeintoexistence,searchvolumeis consistently increasing with the falling trend for Wireless Sensor Networks.AsperGoogle’ssearchforecast(dottedlineinFig.3),this trendislikelytocontinueasotherenablingtechnologiesconverge toformagenuineInternetofThings.

3.3.IoTelements

We present a taxonomy that will aid in defining the compo- nents required for the Internet of Things from a high level per- spective. Specific taxonomies of each component can be found elsewhere [12–14]. There are three IoT components which enables seamless ubicomp: (a) Hardware—made up of sensors, actuators and embedded communication hardware (b) Middleware—on de- mand storage and computing tools for data analytics and (c) Presentation—novel easy to understand visualization and interpre- tation tools which can be widely accessed on different platforms and which can be designed for different applications. In this sec- tion, we discuss a few enabling technologies in these categories which will make up the three components stated above.

1648J.Gubbietal./FutureGenerationComputerSystems29(2013)1645–1660

Fig. 2. Gartner 2012 Hype Cycle of emerging technologies.

Source: Gartner Inc. [10].

Fig. 3. Google search trends since 2004 for terms Internet of Things, Wireless Sensor Networks, Ubiquitous Computing.

3.3.1.RadioFrequencyIdentification(RFID)

RFIDtechnologyisamajorbreakthroughintheembeddedcom-municationparadigmwhichenablesdesignofmicrochipsforwire-lessdatacommunication.Theyhelpintheautomaticidentification of anything they are attached to acting as an electronic barcode [15,16].ThepassiveRFIDtagsarenotbatterypoweredandtheyusethepowerofthereader’sinterrogationsignaltocommunicatethe IDtotheRFIDreader.Thishasresultedinmanyapplicationspar- ticularlyinretailandsupplychainmanagement.Theapplications can be found in transportation (replacement of tickets, registra- tion stickers) and access control applications as well.Thepassivetagsarecurrentlybeingusedinmanybankcardsandroadtolltags whichareamongthefirstglobaldeployments.ActiveRFIDreaders have their own battery supply and can instantiate the communi- cation. Of the several applications, the main application ofactive RFIDtagsisinportcontainers[16]formonitoringcargo.

3.3.2.Wireless Sensor Networks(WSN)

Recenttechnologicaladvancesinlowpowerintegratedcircuits and wireless communications have made available efficient,low

cost, low power miniature devices for use in remote sensing ap- plications. The combination of these factors has improved the vi- ability of utilizing a sensor network consisting of a large number of intelligent sensors, enabling the collection, processing, analysis and dissemination of valuable information, gathered in a variety of environments [7]. Active RFID is nearly the same as the lower endWSNnodeswithlimitedprocessingcapabilityandstorage.The scientific challenges that must be overcome in order to realize the enormous potential of WSNs are substantial and multidisciplinary in nature [7]. Sensor data are shared among sensor nodes and sent to a distributed or centralized system for analytics. The compo- nents that make up the WSN monitoring network include:

(a)WSN hardware—Typically a node (WSN core hardware) con- tains sensor interfaces, processing units, transceiver units and power supply. Almost always, they comprise of multiple A/D converters for sensor interfacing and more modern sensor nodes have the ability to communicate using one frequency band making them more versatile [7].

(b)WSNcommunicationstack—Thenodesareexpectedtobede- ployedinanad-hocmannerformostapplications.Designing

J.Gubbietal./FutureGenerationComputerSystems29(2013)1645–16601649

anappropriatetopology,routingandMAClayeriscriticalforthe scalability and longevity of the deployed network.Nodes inaWSNneedtocommunicateamongthemselvestotransmit data in single or multi-hop to a base station. Node dropouts, andconsequentdegradednetworklifetimes,arefrequent.The communicationstackatthesinknodeshouldbeabletointer- actwiththeoutsideworldthroughtheInternettoactasagate- waytotheWSNsubnetandtheInternet[17].

(c)WSNMiddleware—Amechanismtocombinecyberinfrastruc- turewithaServiceOrientedArchitecture(SOA)andsensornet- workstoprovideaccesstoheterogeneoussensorresourcesin a deployment independent manner [17]. This is based on the idea of isolating resources that can be used by several appli- cations. A platform-independent middleware for developing sensor applications is required, such as an Open Sensor Web Architecture(OSWA)[18].OSWAisbuiltuponauniformsetof operationsandstandarddatarepresentationsasdefinedinthe SensorWebEnablementMethod(SWE)bytheOpenGeospatialConsortium(OGC).

(d)Secure Data aggregation—An efficient and secure data aggre- gationmethodisrequiredforextendingthelifetimeofthenetwork as well as ensuring reliable data collected from sen- sors[18].NodefailuresareacommoncharacteristicofWSNs,the network topology should have the capability to heal it- self.Ensuringsecurityiscriticalasthesystemisautomatically linkedtoactuatorsandprotectingthesystemsfromintrudersbecomes veryimportant.

3.3.3.Addressingschemes

Theabilitytouniquelyidentify‘Things’iscriticalforthesuccess of IoT. This will not only allow us to uniquely identify billionsof devices but also to control remote devices through the Internet. The few most critical features of creating a unique address are: uniqueness,reliability,persistenceandscalability.

Everyelementthatisalreadyconnectedandthosethatarego- ingtobeconnected,mustbeidentifiedbytheiruniqueidentifica- tion,locationandfunctionalities.ThecurrentIPv4maysupportto anextentwhereagroupofcohabitingsensordevicescanbeidenti- fiedgeographically,butnotindividually.TheInternetMobilityat-tributesintheIPV6mayalleviatesomeofthedeviceidentification problems; however, the heterogeneous nature of wireless nodes, variabledatatypes,concurrentoperationsandconfluenceofdata fromdevicesexacerbatestheproblemfurther[19].

Persistent network functioning to channel thedatatrafficubiquitously and relentlessly is another aspect ofIoT.Although,theTCP/IPtakescareofthismechanismbyroutinginamorereliableandefficientway,fromsourcetodestination,theIoTfacesa bottleneck at the interface between the gatewayandwirelesssensordevices.Furthermore,thescalabilityofthedeviceaddressoftheexistingnetworkmustbesustainable.Theadditionofnetworksand devices must not hamper the performance ofthenetwork,the functioning of the devices, the reliability of the dataoverthenetworkortheeffectiveuseofthedevicesfromtheuserinterface.Toaddresstheseissues,theUniformResourceName(URN)sys- tem is considered fundamental for the development ofIoT.URNcreates replicas of the resources that can be accessedthroughtheURL. With large amounts of spatial data being gathered, itisof-ten quite important to take advantage of the benefitsofmetadatafor transferring the information from a database to theuserviathe Internet [20]. IPv6 also gives a very good option toaccesstheresourcesuniquelyandremotely.Anothercriticaldevelopmentinaddressing is the development of a lightweight IPv6 that willen-

able addressing home appliances uniquely.

Wirelesssensornetworks(consideringthemasbuildingblocks of IoT), which run on a different stack compared totheInternet,cannot possess IPv6 stack to address individually and hence a

subnet with a gateway having a URN will be required. With this in mind, we then need a layer for addressing sensor devices by therelevantgateway.Atthesubnetlevel,theURNforthesensor devicescouldbetheuniqueIDsratherthanhuman-friendlynames as in the www, and a lookup table at the gateway to addressthis device.Further,atthenodeleveleachsensorwillhaveaURN(as numbers) for sensors to be addressed by the gateway. The entire networknowformsawebofconnectivityfromusers(high-level) tosensors(low-level)thatisaddressable(throughURN),accessible (through URL) and controllable (throughURC).

3.3.4.Datastorageandanalytics

One of the most important outcomes of this emerging field is thecreationofanunprecedentedamountofdata.Storage,owner- shipandexpiryofthedatabecomecriticalissues.Theinternetcon- sumesupto5%ofthetotalenergygeneratedtodayandwiththese typesofdemands,itissuretogoupevenfurther.Hence,datacen- ters that run on harvested energy and are centralized willensure energyefficiencyaswellasreliability.Thedatahavetobestored andusedintelligentlyforsmartmonitoringandactuation.Itisim- portanttodevelopartificialintelligencealgorithmswhichcouldbe centralized or distributed based on the need. Novel fusion algo- rithms need to be developed to make sense of the data collected. State-of-the-art non-linear, temporal machine learning methods basedonevolutionaryalgorithms,geneticalgorithms,neuralnet- works,andotherartificialintelligencetechniquesarenecessaryto achieveautomateddecisionmaking.Thesesystemsshowcharac- teristicssuchasinteroperability,integrationandadaptivecommu- nications.Theyalsohaveamodulararchitecturebothintermsof hardwaresystemdesignaswellassoftwaredevelopmentandare usuallyverywell-suitedforIoTapplications.Moreimportantly,a centralized infrastructure to support storage and analytics is re- quired.ThisformstheIoTmiddlewarelayerandtherearenumer- ouschallengesinvolvedwhicharediscussedinfuturesections.As of2012,Cloudbasedstoragesolutionsarebecomingincreasingly popularandintheyearsahead,Cloudbasedanalyticsandvisual- izationplatformsareforeseen.

3.3.5.Visualization

VisualizationiscriticalforanIoTapplicationasthisallowsthe interactionoftheuserwiththeenvironment.Withrecentadvances intouchscreentechnologies,useofsmarttabletsandphoneshas becomeveryintuitive.ForalaypersontofullybenefitfromtheIoT revolution,attractiveandeasytounderstandvisualizationhasto becreated.Aswemovefrom2Dto3Dscreens,moreinformation canbeprovidedinmeaningfulwaysforconsumers.Thiswillalso enablepolicymakerstoconvertdataintoknowledge,whichiscrit- icalinfastdecisionmaking.Extractionofmeaningfulinformation from raw data is non-trivial. This encompasses both event detec- tionandvisualizationoftheassociatedrawandmodeleddata,with informationrepresentedaccordingtotheneedsoftheend-user.

4.Applications

Thereareseveralapplicationdomainswhichwillbeimpacted bytheemergingInternetofThings.Theapplicationscanbeclassi- fiedbasedonthetypeofnetworkavailability,coverage,scale,het- erogeneity, repeatability, user involvement and impact [21]. We categorizetheapplicationsintofourapplicationdomains:(1)Per- sonal and Home; (2) Enterprize; (3) Utilities; and (4) Mobile.This is depicted inFig. 1, which represents Personal and Home IoT at the scale of an individual or home, Enterprize IoT at the scale of a community, Utility IoT at a national or regional scale and Mo- bileIoTwhichisusuallyspreadacrossotherdomainsmainlydue to the nature of connectivity and scale. There is a hugecrossover

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inapplicationsandtheuseofdatabetweendomains.Forinstance, thePersonalandHomeIoTproduceselectricityusagedatainthe house and makes it available to the electricity (utility) company which can in turn optimize the supply and demand in theUtility IoT.Theinternetenablessharingofdatabetweendifferentservice providersinaseamlessmannercreatingmultiplebusinessoppor- tunities.Afewtypicalapplicationsineachdomainaregiven.

4.1.Personal andhome

Thesensorinformationcollectedisusedonlybytheindividuals who directly own the network. Usually WiFi is used as theback- bone enabling higher bandwidth data (video) transfer aswellashighersamplingrates(Sound).

Ubiquitoushealthcare[8]hasbeenenvisionedforthepasttwo decades. IoT gives a perfect platform to realize this vision using bodyareasensorsandIoTbackendtouploadthedatatoservers. Forinstance,aSmartphonecanbeusedforcommunicationalong withseveralinterfaceslikeBluetoothforinterfacingsensorsmea- suringphysiologicalparameters.Sofar,thereareseveralapplica- tionsavailableforAppleiOS,GoogleAndroidandWindowsPhoneoperatingsystemsthatmeasurevariousparameters.However,itis yet to be centralized in the cloud for general physicians to access thesame.

An extension of the personal body area network is creating a home monitoring system for elderly care, which allows the doctortomonitorpatientsandtheelderlyintheirhomesthereby reducing hospitalization costs through early intervention and treatment[22,23].

Control of home equipment such as air conditioners, refriger- ators, washing machines etc., will allow better home and energy management.ThiswillseeconsumersbecomeinvolvedintheIoT revolution in the same manner as the Internet revolution itself [24,25]. Social networking is set to undergo another transforma- tionwithbillionsofinterconnectedobjects[26,27].Aninteresting developmentwillbeusingaTwitterlikeconceptwhereindividual ‘Things’inthehousecanperiodicallytweetthereadingswhichcan be easily followed from anywhere creating a TweetOT. Although thisprovidesacommonframeworkusingcloudforinformationac- cess,anewsecurityparadigmwillberequiredforthistobefully realized[28].

4.2.Enterprize

We refer to the ‘Network of Things’ within a work environment as an enterprize based application. Information collected from such networks are used only by the owners and the data may be released selectively. Environmental monitoring is the first common application which is implemented to keep track of the number of occupants and manage the utilities within the building (e.g., HVAC,lighting).

Sensorshavealwaysbeenanintegralpartofthefactorysetup forsecurity,automation,climatecontrol,etc.Thiswilleventually be replaced by a wireless system giving the flexibility to make changestothesetupwheneverrequired.ThisisnothingbutanIoT subnetdedicatedtofactorymaintenance.

One of the major IoT application areas that is already draw- ing attention is Smart Environment IoT [21,28]. There areseveral testbedsbeingimplementedandmanymoreplannedinthecom- ingyears.SmartenvironmentincludessubsystemsasshowninTa-ble 1and the characteristics from a technological perspective are listedbriefly.Itshouldbenotedthateachofthesubdomainscover manyfocusgroupsandthedatawillbeshared.Theapplicationsor use-caseswithintheurbanenvironmentthatcanbenefitfromthe realization of a smart city WSN capability are shown inTable 2. These applications are grouped according to their impact areas.

Thisincludestheeffectoncitizensconsideringhealthandwellbe- ing issues; transport in light of its impact on mobility,productiv- ity,pollution;andservicesintermsofcriticalcommunityservices managedandprovidedbylocalgovernmenttocityinhabitants.

4.3.Utilities

Theinformationfromthenetworksinthisapplicationdomain isusuallyforserviceoptimizationratherthanconsumerconsump- tion.Itisalreadybeingusedbyutilitycompanies(smartmeterby electricitysupplycompanies)forresourcemanagementinorderto optimize cost vs. profit. These are made up of very extensivenet- works(usuallylaidoutbylargeorganizationonaregionalandna- tional scale) for monitoring critical utilities and efficientresource management. The backbone network used can vary betweencel- lular,WiFiandsatellitecommunication.

SmartgridandsmartmeteringisanotherpotentialIoTapplica- tionwhichisbeingimplementedaroundtheworld[38].Efficient energyconsumptioncanbeachievedbycontinuouslymonitoring every electricity point within a house and using this information tomodifythewayelectricityisconsumed.Thisinformationatthe cityscaleisusedformaintainingtheloadbalancewithinthegrid ensuringhighqualityofservice.

VideobasedIoT[39],whichintegratesimageprocessing,com- putervisionandnetworkingframeworks,willhelpdevelopanew challenging scientific research area at the intersection of video, infrared,microphoneandnetworktechnologies.Surveillance,the most widely used camera network applications, helps track tar- gets,identifysuspiciousactivities,detectleftluggageandmonitor unauthorizedaccess.Automaticbehavioranalysisandeventdetec- tion (as part of sophisticated video analytics) is in its infancyand breakthroughs are expected in the next decade as pointed out in the2012GartnerChart(referFig.2).

Water network monitoring and quality assurance of drinking waterisanothercriticalapplicationthatisbeingaddressedusing IoT. Sensors measuring critical water parameters are installed at important locations in order to ensure high supply quality. This avoids accidental contamination among storm waterdrains, drinking water and sewage disposal. The same network can be extended to monitor irrigation in agricultural land. The network is also extended for monitoring soil parameters which allows informeddecisionmakingconcerningagriculture[40].