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A Decision-Making Tool for a Regional Network of Clinical Laboratories. Ali Erdem Banak Berk Torun Ladin Uğur. Main Outline. Introduction Process Problem Definition Project Scope Literature Review Directed Graph Mathematical Model Sensitivity Analysis DSS Implementation
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A Decision-Making Tool for a RegionalNetwork of ClinicalLaboratories Ali Erdem Banak Berk Torun Ladin Uğur
MainOutline • Introduction • Process • Problem Definition • Project Scope • LiteratureReview • DirectedGraph • Mathematical Model • SensitivityAnalysis • DSS Implementation • Program Architecture • DSS Utilization • Conclusions • HealthcareResearch in Turkey
Introduction • AndalusianHealthService (AHA) is thegovernmentrunhealthcaresystemforautonomouscommunity of Andalusia
Providesuniversalhealthcare service tomorethan 8 millionpeople • As of 1 January 2007 employs 83,132 professionals, 20,810 of them in primary care and 62,322 in specialized care • Has laboratoriesallaroundtheregionunderthe name RNCL
Process • RNCL collectsbiologicalsamplesfromanylab in itsnetwork • Samplesareanalyzed in RNCL’sownlabsoroutsourcedto a privatelab • Resultsare sent backtothelab in whichtheywerecollected • In 2008, AHA decidedtorun a projecttoefficientlyallocatetheirresources
Problem Definition • Lack of planningprocedureinfluencesthechoice of theprocessinglab • Excessiveshippingcostsbecause of theindividualcontracts • Althoughlabs can handlelargerworkloads, theyprefersendingtheteststotheirpreferredhospitals
Scope of the Project • A newreference model toincreasecooperationbetweenlaboratories • A newplanningproceduretobetterutilizeRNCL’slaboratoriesandreducethenumber of outsourcedtests
Regardless of time needed, DSS must be abletouseinput data toresolvedifferentscenarios • Itmust be abletoanalyzetheworkloadandflowassignments • Itmust be abletocomparescenarios
LiteratureReview • EkşioğluandJin (2006) CrossFacilityProductionandTransportationPlanning Problem withPerishableInventory • Ekşioğlu et al (2007) A LagrangeanHeuristicForIntegratedProductionandTransportationPlanningProblems in a Dynamic, Multi-Item, TwoLayerSupplyChain
AndreattaandLulli (2008) A Multi-Period TSP withStochasticRegularandUrgentDemands • OswaldandStirn (2008) A VehicleRoutingAlgorithmfortheDistribution of FreshVegetablesandSimilarPerishableFood • AmbrossinoandSciomachen (2007)A FoodDistribution Network Problem: A CaseStudy
DirectedGraph • SC: ServingCenter • OC: OutsourcingCenter • POE: Point of Extraction • DTP: Demand Transfer Point Arcslongerthan 250 km areexcludedfromthe model forsamplestability
Mathematical Model • Problem is modelled as multicommodity minimum costflow problem. • Decisionvariablesare link selectionandflowassignment. • Discountfactorsareattachedtotheflow in eachconnection. • 488 verticesand 2477 arcsforAndalusia • 6 differenttypes of samples
Objectivefunctionincludes;shipping, transhipment, processing, outsourcing, penaltycostfor not achieving minimum workloadandpenaltyforexcesstranshipment.
Wehavepenaltycostsforexcesstranshipmentsandlowusage of RNCL laboratories.
Per-unitshipmentcostalongeach link is a discretefunction of theflowalongthat link since it is possibletohave a betterper-unitpricefor a largerbatch. • Firmsofferthesame set of discountfactorforeach link. • Eachrange has lowerbound, upperboundanddiscountfactor.
Constraints • A1 is similartoequalizing C(0k)’s to 0 • A2 regulatesdemand. • A3 is thecapacityconstraint. • A4 is theflowbalanceequation.
A5 is transhipmentbalance. • A6 and A7 is trafficbounds. • A8 forces us touse 1 carrier in a specificrange. • A9 relatesflowvariables.
A9 relatesflowvariables. • A10 decidesdiscountfactors.
Aftergettingthesolution plan fromthe model, AGA (averagegeographicalaccessibility) is found in ordertoestimateexpectedquality of service (QoS) whichindicatesthethenumber of transhipmentseach test needstoreachthelaboratory.
Sensitivity Analysis • Sensitivityanalysisaboutdifferentscenarioswillprovideinsights. • Design of experiments (DOE) is used. • 3 type of parameters. • Parametersrelatedtooptimizationtool (Stop time) • Model parameters (penaltycosts) • Network topology (Size andcomplexity)
4 responsesaremeasured • Value of objectivefunction • AGA indicator • Total outsourcingcost • Gaptothe optimal solution • Singlefactoranalysis of variance, single-degree-of-freedom ANOVA andanalysis of meanstechnique is used
ConclusionsFrom Analysis • Allparametershavesignificanteffect on theresponses; exceptthethresholdfortriggeringthepenaltycost of excesstranshipment. • Network size is themostinfluentialparameter. • Outsourcingleveldoes not depend on network size. • Quality of service is affectedbyalltheparametersexceptthethresholdfortriggeringthepenaltycost of excesstranshipment.
DSS ToolImplementation • A collaborativeprojectwaslaunched in conjuctionwithnew RNCL planningapproach • Objectivewastodevelop a plan formostresourceconsuming service: provision of laboratories
RNCL authoritiesprovided data andsharedbusinessrules • Theyalsoincreasedawarenesstoeliminateanyresistanceto DSS by RNCL staff.
Program Architecture • An optimization engine coded in AMPL • Inputsaretakenby engine from RNCL database • DSS is web-based • Graphicaluserinterface is embeddedforuser-friendliness • Via GUI differentscenarios can be tested
Resultingroutesaredisplayed on GoogleMaps API • Optimal routes can be savedforfuturecomparisons
DSS Utilization • In 2009, RNCL usedthe DSS todecidewhichsubset of newfacilitiestoactivatefromallalternatives • Costsfellfrom 8 million € to 0,2 million € in 2008-2009 period, primarilyduetoreducedoutsourcing
Conclusions • Recommendedorganizationalchangeswere • A newreference model • Centralizedmanagement of logistics • A huge problem with 47000 variables, 14300 of themarebinaryand 36000 constraints • Solutionsareapproximatedtoreducecomputation time (limitedwith 1800 seconds), upto %10 awayfrom optimum
HealthcareResearch in Turkey • Yücel, E., Salman F. S., Örmeci E. L., Gel, E. S. , Gel A., “Logistics of ClinicalTesting: BicriteriaHeuristics for Routing and Scheduling of Specimen Collection,” 2011. (Research in Progress)
ClinicalSpecimenCollection Problem (CSCP) • Bicriteria problem • Primary: Thenumber of specimencollected is maximizedthrough a MIP model constrainedby an upperbound • Secondary: Total transportationcost is minimizedwithMyopicTourBuildingHeuristicand Tabu SearchHeuristicconstrainedby a lowerbound • Bothlevelsare NP-hard