Page - 197 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 270 Figure7.Sensitivityanalysis resultsof thesub-criteria in theenvironmentgroup. Figure8.Sensitivityanalysis resultsof thesub-criteria in the technologygroup. Aboveall, electricvehiclechargingstationA3alwayssecures itsbest ranking,nomatterhowthe sub-criteriaweightschange. It canbeverifiedthat theoptimalEVCSsitingresultsusingGRA-VIKOR andcombinationweightingtechniques is robustandeffective. Thisstudycandistinguishthepriorities ofalternativesmoreeasily,andthushelpdecisionmakersevaluateandidentify thebestalternative andmore improvement items. 8.Conclusions Acomprehensive framework for selecting theoptimal site forEVCSs is studied in thispaper. Consideringtheconceptofextendedsustainability, experts’opinions,andindustrybackground, the finalevaluationsub-criteria foroptimalEVCSsitingaredeterminedbasedonFDM,whichconsistsof fourpillars: economy,society,environmentandtechnology. Toaddress the fuzzinessanduncertainty ofsubjective factorandhuman judgment,a fuzzyGRA-VIKORmethodisemployedtodetermine the optimalEVCSsite. It isworthmentioningthatGRAisusedtomeasure thedistancesof fuzzynumbers betweenalternatives to ideal solutions in thisstudy,whichcanefficientlyavoidthepriorityresultof fuzzynumbers,aswellasensureaconsistent ranking list forallalternatives.Moreover, inorder to provideascientificweightingsystem,thesub-criteriaweightsaredeterminedcombiningthesubjective weightsofexperts’opinionsaswellas theobjectiveweightsof theentropymethod,whichupdates the weightingprocessofconventional fuzzyVIKOR.Theevaluationresults showsthat thesub-criteriaC9 andC10affiliatedwith theenvironmentobtainmuchmoreattentionfromtheexpertsgroup,andthe alternativeA3 inTianjinNankaidistrict isdeterminedas theoptimalEVCSsite. Lastbutnot least, to test therobustnessandeffectivenessofdecisionresults, asensitivityanalysis ispresented,which showedthat thesitingresultsremainstablenomatterhowthevvalueandsub-criteriaweightschange. Moreover, it canalsobe foundthatC1,C3andC8are thesensitivesub-criteriawhichdramatically affect theoptimalEVCSsitingresult. Althoughthis studyrealizedtheoptimalsitingofEVCSsbyusingFDM,combinationweighting andfuzzyGRA-VIKORtechniques, limitationsmaystill existdueto thefact theevaluationcriteria will changealongwithobjectiveconditions.Moreover, fromamethodologicalperspective, itwould behelpful to test theproposedframeworkwithotherapproaches. Theresults fromtheseapproaches couldbecomparedwith theresults in thispaper,which isanoutline for the futureresearch. 197