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CTL.SC4x – Technology and Systems
Key Concepts Document
This document contains the Key Concepts for the SC4x course.
These are meant to complement, not replace, the lesson videos and slides. They are intended to
be references for you to use going forward and are based on the assumption that you have
learned the concepts and completed the practice problems.
This draft was created by Dr. Alexis Bateman in the spring of 2017.
This is a draft of the material, so please post any suggestions, corrections, or recommendations
to the Discussion Forum under the topic thread “Key Concept Documents Improvements.”
Thanks,
Chris Caplice, Eva Ponce and the SC4x Teaching Community
Spring 2017 v1
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
1
Table of Contents
IntroductiontoDataManagement.......................................................................................................4
DataManagement..................................................................................................................................4
QueryingtheData...................................................................................................................................5
DataModeling.....................................................................................................................................7
RelationalModels....................................................................................................................................7
DesigningDataModels...........................................................................................................................8
RelationshipsandCardinality..................................................................................................................8
Keys.........................................................................................................................................................9
DatabaseNormalization.....................................................................................................................11
ObjectivesofNormalization..................................................................................................................11
Summaryoffivenormalforms..............................................................................................................12
ClientServerArchitecture......................................................................................................................13
DatabaseQueries...............................................................................................................................14
StructuredQueryLanguage...................................................................................................................14
CreatingDatabasesandTables.............................................................................................................16
DatabaseConditional,Grouping,andJoins........................................................................................18
DatabaseConditionalClauses...............................................................................................................18
SortingandSamplingData....................................................................................................................19
JoiningMultipleTables..........................................................................................................................21
IntroductiontoMachineLearning......................................................................................................23
OverviewofMachineLearningAlgorithms...........................................................................................23
ModelQuality........................................................................................................................................24
MachineLearningAlgorithms............................................................................................................26
Dimensionalityreduction.......................................................................................................................26
Principalcomponentanalysis(PCA)......................................................................................................26
Clustering..............................................................................................................................................27
Classifications........................................................................................................................................27
Comparingpredictoraccuracy..............................................................................................................29
Sensitivityandspecificity.......................................................................................................................29
SupplyChainSystems-ERP................................................................................................................31
SupplyChainITSystems........................................................................................................................31
EnterpriseResourcePlanning................................................................................................................31
ERPCommunication..............................................................................................................................33
TheValueofERPforSCM......................................................................................................................34
SupplyChainSystems-SupplyChainModules...................................................................................36
AdvancedPlanningSystems..................................................................................................................37
TransportationManagementSystems(TMS)........................................................................................38
ManufacturingExecutionSystems........................................................................................................41
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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2
SupplyChainSystems-SoftwareSelection&Implementation...........................................................42
Architecture...........................................................................................................................................42
CloudComputing...................................................................................................................................42
SoftwareVendorSelection....................................................................................................................45
Implementation.....................................................................................................................................46
TechnologyTrends.............................................................................................................................48
Trend:AutonomousVehicles.................................................................................................................48
Trend:DeliveryDrones..........................................................................................................................48
Trend:MobileComputing......................................................................................................................49
AdditiveManufacturing........................................................................................................................49
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
3
Introduction to Data Management
Summary
Supplychainsaremovingatever-fasterrateswithtechnologyandsystemssupportingthis
movement.Datamanagementplaysacriticalroleinenablingsupplychainstomoveatthe
speedandprecisiontheydotoday,andtheneedforadvanceddatamanagementwillonly
continue.
Inrecentyearstherehasbeenanexplosionofinformationandthisisespeciallytrueinsupply
chains.AfewexamplesintroducedincludeAmazon’smassivesupplychainsselling480million
uniqueitemsto244millioncustomerswhileUPSisdelivering20millionpackagesto8.4million
deliverypoints.Thisinformationiscomingfrommultiplesources,inadditiontosensors,the
“internetofthings”,andregulationsrequiringincreasingamountsofinformation.
Allofthisinformationiscommonlyreferredtoasthe“BigData”challenge.Dataisdrivingour
modernworld,buthowcanwebesureofitanduseitmosteffectively?Aswewillreview–
dataismessy,itrequirescleaningandprogramming.Dataisfrequentlytrappedinsiloes
comingfromdifferentsources,whichmakesworkingwithitmorechallenging.Inaddition,data
isbigandgettingevenbiggerdaily.Thetoolswehaveallbecomecomfortablewith
(spreadsheets)cannolongerhandlethatamountofdata,sowemustusedifferenttoolsto
enablegreateranalysis.
Tobetterunderstandtheroleofdataandhowtomanageit,thefollowingsummariescoveran
introductiontodatamanagement,datamodeling,anddatanormalization–togetusstartedon
asolidgroundwithhandlinglargedatasets–anabsoluteessentialinsupplychain
management.
Data Management
Indatamanagementsupplychainmanagerswillbefacedwithimmensecomplexity.This
complexityisinfluencedbythevolume(howmuch),velocity(pace),variety(spread),and
veracity(accuracy).Eachofthesecomponentswillinfluencehowdataistreatedandusedin
thesupplychain.
Thereareseveralreoccurringissuesthatsupplychainmanagersmustbeawareofastheyare
workingwithdata:
• Isthedataclean?
• Isthedatacomplete?
• Whatassumptionsareyoumakingaboutthedata?
• Aretheresultsmakingsense?HowcanIcheck?
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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4
Cleaningdataisoneofthemostimportant;yettimeconsumingprocessesindataanalysis.It
cangreatlyinfluencetheoutcomeofanalysisifnotcompletedproperly.Therefore–SC
professionalsshouldalwaysplanenoughtimeforbasicdatachecks(meaningifyougetgarbage
in,youwillgetgarbageout).
Thereareseveraltypicalchecksyoushouldalwayslookfor:
• Invalidvalues-negative,text,toosmall,toobig,missing
• Mismatchesbetweenrelateddatasets-#ofrows,#ofcols
• Duplication–uniqueidentifiers
• Humanerror–wrongdates,invalidassumptions
• Alwaysexploretheoutliers–theyarethemostinteresting!
Whencleaningdata,youshouldbeorganized.Thismeansyoumustmakesuretoversionthe
documentsyouareworkingwithandkeeptrackofdatachanges.
Querying the Data
Onceyouhaveacleanandorganizedsetofdata,queryingthedatacanmakedataextremely
powerful.Queryingdatareferstotheactionofretrievingdatafromyourdatabase.Becausea
databasecanbesolarge–weonlywanttoqueryfordatathatfitsacertaincriteria.
Thereareseveralbasicoptionsthatcanhelpyougetsomequickanswersinbigdatasets,such
asusingPivotTables:
• TherearedatasummarizationtoolsfoundinLibreOffice,GoogleSheets,andExcel
• Theyautomaticallysort,count,totaloraveragethedatastoredinonetableor
spreadsheet,displayingtheresultsinasecondtableshowingthesummarizeddata.
• Veryusefulintabulatingandcross-tabulatingdata
No more spreadsheets!
Unfortunately,aswedivedeeperintothebigdatachallenge,wefindthatspreadsheetscanno
longerserviceallofourneeds.Wehavethechoiceofworkingwithstructuredorunstructured
data.Adatabaseisastructuredwayofstoringdata.Youcanimposerules,constraintsand
relationshipsonit.Furthermoreitallowsfor:
• Abstraction:Separatesdatausefromhowandwherethedataisstored.Thisallows
systemstogrowandmakesthemeasiertodevelopandmaintainthroughmodularity.
• Performance:Databasemaybetunedforhighperformanceforthetaskthatneedsto
bedone(manyreads,manywrites,concurrency)
Spreadsheetsareunstructureddata.Youhaveadatadumpintoonspreadsheetandyouneed
tobeabletodolotsofdifferentthings.Spreadsheetswillalwaysbegreatforalimitedsetof
analysissuchasinformal,causal,andone-offanalysisandprototyping.Unfortunatelytheyare
nolongersuitedforrepeatable,auditable,orhighperformanceproduction.Unstructureddata
commonlyhasproblemswith:redundancy,clarity,consistency,security,andscalability.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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5
Learning Objectives
•
•
•
•
Understandtheimportanceofdatainsupplychainmanagement.
Reviewtheimportanceofhighqualityandcleandatabases.
Recognizethepowerofqueryingdata.
Differentiatebetweenunstructuredandstructureddataandtheneedfortoolsbeyond
spreadsheets.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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6
Data Modeling
Summary
Nowthatwehavebeenintroducedtodatamanagementandtheissueofbigdata,wenow
deepdriveintodatamodelingwherewelearnhowtoworkwithdatabases.Datamodelingis
thefirststepindatabasedesignandprogrammingtocreateamodelforhowdatarelatesto
eachotherwithinadatabase.Datamodelingistheprocessoftransitioningalogicalmodelinto
aphysicalschema.
Tounderstandtheprocessofdatamodeling,wereviewseveralcomponentsincluding
relationaldatabases,dataorganization,datamodelsfordesigningdatabases,andwhat
constitutesagooddatamodel.Adatamodelconsistsofseveralpartsincluding:entitiesand
attributes,primarykeys,foreignkeys,andrelationshipsandcardinality.
Relational Models
Therelationalmodelisanapproachtomanagingdatathatusesstructureandlanguagewhere
alldataisgroupedintorelations.Arelationalmodelprovidesamethodforspecifyingdataand
queries.Itisbasedonfirst-orderpredicatelogic,whichwasdescribedbyEdgarF.Coddin1969.
Thislogicdefinesthatalldataisrepresentedintermsoftuples,groupedintorelations.There
areseveraldefinitionstobefamiliarwithaswereviewedpreviouslywithrelationalmodels:
• Entity:object,conceptorevent
• Attribute(column):acharacteristicofanentity
• Recordortuple(row):thespecificcharacteristicsorattributevaluesforoneexampleof
anentity
• Entry:thevalueofanattributeforaspecificrecord
• Table:acollectionofrecords
• Database:acollectionoftables
Tables and Attributes
Datainrelationaltablesareorganizedintotables,whichrepresententities.Singletableswithin
adatabasecanbeseenassimilartoaspreadsheet.However,weusedifferentwordstoreferto
“rows”and“columns”.Attributesarethecharacteristicsofanentity.
Tables
• Tablesrepresententities,whichareusuallypluralnouns
• Tablesareoftennamedaswhattheyrepresent(typicallypluralnouns,withoutspaces):
e.g.Companies,Customers,Vehicles,Orders,etc.
Attributes
• Characteristicsofanentity(table),typicallynouns
• Examplesintheformof:Table(Attr1,Attr2,...AttrN),Vehicles(VIN,Color,Make,
Model,Mileage)
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
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7
EntityTypesandEntityoccurrence:anentityisanyobjectinthesystemwewanttomodeland
store.Anentityoccurrenceisauniquelyidentifiableobjectbelongingtoanentitytype.
Designing Data Models
Thereareseveralstepstodesigningadatabasetostoreandanalyzedata.
1. Developadatamodelthatdescribesthedatainthedatabaseandhowtoaccessit
2. Datamodeldefinestablesandattributesinthedatabase(eachimportantconcept/noun
inthedataisdefinedasatableinthedatabase)
Datamodelshelpspecifyeachentityinatableinastandardizedway.Theyallowtheuserto
imposerules,constraintsandrelationshipsonthedatathatisstored.Italsoallowsusersto
understandbusinessrulesandprocessandanalyzedata.
Rules for a Relational Data Model
Thereareseveralrulesforrelationaldatamodel:
• Actsasaschematicforbuildingthedatabase
• Eachattribute(column)hasauniquenamewithinatable
• Allentriesorvaluesintheattributeareexamplesofthatattribute
• Eachrecord(row)isuniqueinagooddatabase
• Orderingofrecordsandattributesisunimportant
Whatmakesagoodrelationaldatamodel?Agoodrelationalmodelshouldbecompletewithall
thenecessarydatarepresented.Thereshouldbenoredundancy.Businessrulesshouldbe
effectivelyenforced.Modelsshouldalsobereusablefordifferentapplications.Andfinally,it
shouldbeflexibleandbeabletocopewithchangestobusinessrulesordatarequirements.
Relationships and Cardinality
Whenwebegintoworkwiththedata–wehavetounderstandhowdatarelatestoeachother
anddatauniquenessoftheattributes.Someofthiscanbemanagedthroughentitytypesand
attributes.Relationships+cardinality=businessrules.
Entity and Attributes
Anentityisaperson,place,thing,orconceptthatcanbedescribedbydifferentdata.Each
entityismadeofanumberofattributes.Entitytypesshouldbedescribedaspartofthedata
modelingprocess,thiswillhelpwiththedocumentationanddeterminationofbusinessrules.
Howtodrawandentity-relationshipdiagram:
AnERDisagraphicalrepresentationofaninformationsystemthatvisualizestherelationship
betweentheentitieswithinthatsystem.
• ERDorentity-relationshipdiagramisaschematicofthedatabase
• Entitiesaredrawnasboxes
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
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8
•
•
Relationshipsbetweenentitiesareindicatedbylinesbetweentheseentities
Cardinalitydescribestheexpectednumberofrelatedoccurrencesbetweenthetwo
entitiesinarelationshipandisshownusingcrow'sfootnotation(seefiguresbelow)
Cardinality–crow’sfootnotation
GeneralMeanings Mandatoryvs.Optional
DomainValidationEntities:Alsoknownaspicklistsorvalidationlists.Domainvalidation
entitiesareusedtostandardizedatainadatabase,theyrestrictentriestoasetofspecified
values.Theyaretableswithasingleattributethatenforcesvaluesofattributeinrelated
table(s).
Keys
Primarykeysareattributesusedtouniquelyidentifyarecordwhileforeignkeysareattributes
storedinadependententity,whichshowhowrecordsinthedependententityarerelatedto
anindependententity.
Primarykey:oneormoreattributesthatuniquelyidentifyarecord.Theattributehasbe
uniquelysuited.
ForeignKey:Primarykeyoftheindependentorparententitytypeismaintainedasanon-key
attributeintherelated,dependentorchildentitytype,thisisknownastheforeignkey
Compositekey:isaprimarykeythatconsistsofmorethanoneattribute,ex:charterairline,
everyflighthasadifferentnumber.
ManytoManyRelationships:Amanytomanyrelationshipreferstoarelationshipbetween
tablesinadatabasewhenaparententitycontainsseveralchildentitytypesinthesecond
table.ex-Vehiclecanbedrivenbymanydrivers,driverscandrivemanyvehicles.Inthiscasean
associativetable(entity),akajunctiontableisappropriatewheretheprimarykeyofparentis
usedinprimarykeyofchild.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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9
Referential integrity
Referentialintegritymaintainsthevalidityofforeignkeyswhentheprimarykeyintheparent
tablechanges.Everyforeignkeyeithermatchesaprimarykey(orisnull).
Cascaderules:chooseamongdeleteoptions
• Cascaderestrict:Rowsintheprimarykeytablecan’tbedeletedunlessallcorresponding
rowsintheforeignkeytableshavebeendeleted
• Cascadedelete:Whenrowsintheprimarykeytablearedeleted,associatedrowsin
foreignkeytablesarealsodeleted
Learning Objectives
•
•
•
•
•
•
Thedatamodeldescribesthedatathatisstoredinthedatabaseandhowtoaccessit.
Datamodelsenableuserstounderstandbusinessrulesandeffectivelyprocessand
analyzedata.
Understandthatbusinessrulesareimposedonthedatabasethroughrelationshipsand
cardinality.
Recognizethatdatamodelsmayvaryforagivendatasetasbusinesslogicevolves.
Rememberthatthedatamodelingprocessmayrevealinconsistenciesorerrorsinthe
data,whichwillhavetobecorrectedbeforeimportingintoadatabase.
Selectionofentitiesandassociatedattributesfromaflatfileisnotalwaysobvious.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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10
Database Normalization
Summary
Databasenormalization,ornormalization,isanimportantstepindatabasemanagement.
Normalizationisintrinsictorelationaldatabasesandistheprocessoforganizingattributesinto
relations(ortables).Thisprocessisvitalinreducingdataredundancyandimprovingdata
integrity.Inaddition,normalizationhelpsorganizeinformationaroundspecifictopicsthatcan
beusedtodigestthemassiveamountofinformationindatabasesintosomethingdigestible.
WhenSCprofessionalsarepresentedwithlargeamountsofrawdata,thatrawdatamaybe
storedinasingletable,containingredundantinformationorinformationaboutseveral
differentconcepts.Thedatacanbeseparatedintotablesandnormalizedtoallowforbetter
datahandlingandcomprehension.Togettothisplace,updatingadatamodelcanbedone
collaborativelyduringmeetingsanddiscussionstodefinethebusinessrules.Duringupdates,
normalizationpreventsmistakesanddatainconsistencies.Normalizationhelpsprevent
redundancy,confusion,improperkeys,wastedstorage,andincorrectoroutdateddata.
Objectives of Normalization
1. Tofreethecollectionof[tables]fromundesirableinsertion,updateanddeletion
dependencies.
2. Toreducetheneedforrestructuringthecollectionof[tables],asnewtypesofdataare
introduced,andthusincreasethelifespanofapplicationprograms.
3. Tomaketherelationalmodelmoreinformativetousers.
4. Tomakethecollectionof[tables]neutraltothequerystatistics,wherethesestatistics
areliabletochangeastimegoesby.
**Rememberourrelationalmodeldefinitions
• Entity:object,conceptorevent
• Attribute(column):acharacteristicofanentity
• Recordortuple(row):thespecificcharacteristicsorattributevaluesforoneexampleof
anentity
• Entry:thevalueofanattributeforaspecificrecord
• Table:acollectionofrecords
• Database:acollectionoftables
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
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11
Summary of five normal forms
1. Allrowsinatablemustcontainthesamenumberofattributes;nosub-lists,no
repeatedattributes.
2. Allnon-keyfieldsmustbeafunctionofthekey.
3. Allnon-keyfieldsmustnotbeafunctionofothernon-keyfields.
4. Arowmustnotcontaintwoormoreindependentmulti-valuedfactsaboutanentity.
5. Arecordcannotbereconstructedfromseveralsmallerrecordtypes.
Normal Forms
FirstNormalForm–thebasicobjectiveofthefirstnormalform(definedbyCodd)istopermit
datatobequeriedandmanipulated,groundedinfirstorderlogic.Allrowsinatablemust
containthesamenumberofattributes;nosub-lists,norepeatedattributes,identifyeachsetof
relateddatawithaprimarykey.Firstnormalformcanmakedatabasesrobusttochangeand
easiertouseinlargeorganizations.
SecondNormalForms–mustfirstbeinfirstnormalform,allnon-keyfieldsmustbeafunction
oftheprimarykey;onlystorefactsdirectlyrelatedtotheprimarykeyineachrow.
ThirdNormalForm-mustfirstbeinsecondnormalform.Alltheattributesinatableare
determinedonlybythecandidatekeysofthetableandnotbyanynon-primeattributes.Third
normalformwasdesignedtoimprovedatabaseprocessingwhileminimizingstoragecosts.
FourthNormalForm-mustfirstbeinthirdnormalform.Arowshouldnotcontaintwoormore
independent,multi-valuedfactsaboutanentity.Fourthnormalformbeginstoaddressseveral
issueswhenthereisuncertaintyinhowtomaintaintherows.Whentherearetwounrelated
factsaboutanentity,theseshouldbestoredinseparatetables.
FifthNormalForm-mustfirstbeinfourthnormalform.Arecordcannotbereconstructed
fromseveralsmallerrecordtypes.Sizeofthissingletableincreasesmultiplicatively,whilethe
normalizedtablesincreaseadditively.Mucheasiertowritethebusinessrulesfromthethree
tablesinthefifthnormalform,rulesaremoreexplicit.Supplychainstendtohavefifthnormal
formissues.
Normalization Implementation Details
Normalizationensuresthateachfactisstoredinoneandonlyoneplace,toensuredata
remainsconsistent.Normalizingthedatamodelisatechnicalexercise.Itdoesnotchange
businessrules!However,throughtheprocessofmeetingsanddecisionsitmayhelptherules
befurtherdefinedthroughreview.Careindatanormalizationisneededtopreservedata
quality.Therearetimeswhennormalizationisnotanoption–thishappenswhenthereare
large,readonlydatabasesforreportgenerationofdatawarehouses.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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12
Client-servermodel
Client Server Architecture
Client Server Model
Clientscanconnecttoserverstoaccessaspecificserviceusingastandardizedprotocol,see
•  Clientscanconnecttoserverstoaccessaspecificservice
figurebelow.
usingastandardizedprotocol
Web
Applica9on
Client
DatabaseUser
InterfaceClient
MySQL
Database
Server
Analy9cs
Client
46
Database Servers
Databasesarehostedonaserverandnotusuallyaccessiblethroughafilesystemordirectory
structure.Themainoptionsforhostingadatabasesis:onasingleserver,inadatabasecluster,
orasacloudservice.Allofthesesystemsaredesignedtoabstracttheimplementationdetails.
Aclienthassoftwarethatallowsittoconnectandcommunicatewiththedatabaseserverusing
astandardizedprotocol.Therearemanydifferentuserinterfacesformanydatabases.
DatabasescanbeaccessedremotelyorontheInternet.
Learning Objectives
•
•
•
•
•
Identifyandunderstanddatabasenormalization.
Reviewwhywenormalizeourdatamodels.
Understandthestep-by-stepprocessofdatanormalizationandforms.
Learnandapplyhowwenormalizearelationaldatamodel.
Recognizethedrawbacksofnormalization.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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13
Database Queries
Summary
Aswecontinueourdiscussionofdatabasemanagement,wediveintotheissueofdatabase
queries.Theabilitytomakeeffectivequeriesinalargedatabaseenablesustoharnessthe
powerofbigdatasets.SQL(StructuredQueryLanguage)isalanguageandcontainsthe
commandsweusetocreate,manage,andqueryrelationaldatabases.Asinalltechnologyand
systemsapplications,thereareamultitudeofvendorswhoofferSQLvariations,butingeneral
theyhaveacommonsetofdatatypesandcommands.SQLisportableacrossoperatingsystems
andingeneral,portableamongvendors.Havingcoveredthecommonlyuseddatatypesin
previouslessons,inthisnextsectionwewillcoververycommonlyusedqueries.
Structured Query Language
SQLisusedtoquery,insert,update,andmodifydata.UnlikeJava,VisualBasic,orC++,SQLis
notacompleteprogramminglanguage;itisasub-languageofapproximately30statement
types.Itisgenerallyembeddedinanotherlanguageortooltoenabledatabaseaccess.Afew
definitionsweneedtobeawareofasweexploreSQLare:
• Datadefinition:Operationstobuildtablesandviews(virtualtables)
• Datamanipulation:INSERT,DELETE,UPDATEorretrieve(SELECT)data
• Dataintegrity:Referentialintegrityandtransactionsenforceprimaryandforeignkeys
• Accesscontrol:Securityformultipletypesofusers
• Datasharing:Databaseaccessedbyconcurrentusers
AfewissuestomakenoteofasyouworkwithSQListhatithasseveralinconsistencies.For
example,NULLscanbeproblematicandwewillexplorethatlater.Inaddition,whenworking
withSQLitisimportanttorecognizethatitoperationsondeclarativelanguage,notprocedural
language.Thismeansthatyouwritethecommandinsuchawaythatdescribeswhatyouwant
todo,notHOWyouwanttodoit.Itisleftuptotheapplicationtofigureitout.
Variations among SQL Implementation
BecausedifferentdatabasesuseSQL,therecanbevariationinhowSQLisimplemented.The
variationsinclude:
• Errorcodes
• Datatypessupported(dates/times,currency,string/textvariations)
• Whethercasematters(upper,lowercase)
• Systemtables(thestructureofthedatabaseitself)
• Programminginterface(novendorfollowsthestandard)
• Reportandquerygenerationtools
• Implementer-definedvariationswithinthestandard
• Databaseinitialization,openingandconnection
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14
Aswehavealreadylearned,adatatypedefineswhatkindofvalueacolumncancontain.
However,becausethereisvariationacrossdatabases–wewillusethedatatypesforMySQL
forthepurposeofthisdiscussion.MySQLhasthreemaindatatypes:numeric,strings(text),
anddates/times.Seethefollowingfigures:
CoreMySQLDataTypes-Numeric
CoreMySQLDataTypes– Numeric
NumericType
Description
INT
Astandardinteger
BIGINT
Alargeinteger
DECIMAL
Afixed-pointnumber
FLOAT
Asingle-precision,floating-pointnumber
DOUBLE
Adouble-precision,floating-point number
BIT
Abitfield
CoreMySQLDataTypes– Strings(Text)
CoreMySQLDataTypes–Strings(Text)
String Type
Description
CHAR
Afixed-length,non-binarystring(character)
VARCHAR
Avariable-length,non-binarystring
NCHAR
Sameasabove +UnicodeSupport
NVARCHAR
Sameasabove +UnicodeSupport
BINARY
Afixed-length,binarystring
VARBINARY
Avariable-length,binarystring
TINYBLOB
AverysmallBLOB(binarylargeobject)
BLOB
AsmallBLOB
TEXT
Asmall,non-binarystring
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7
8
15
CoreMySQLDataTypes– Dates/Times
CoreMySQLDataTypes–Dates/Times
Date /TimeType Description
DATE
Adatevaluein'CCYY-MM-DD' format
TIME
Atimevaluein'hh:mm:ss' format
DATETIME
Date/Timein'CCYY-MM-DDhh:mm:ss’format
TIMESTAMP
Timestampin'CCYY-MM-DDhh:mm:ss’format
YEAR
AyearvalueinCCYYorYYformat
Creating Databases and Tables
Togetstarted,wewillneedtoknowhowtocreatedatabasesandtables.WhileMySQLcanbe
anintimidatingprogram,butonceyoumastersomeofthebasics,youwillbeabletowork
effectivelywithlargedatasets.
• TocreateaDatabase,weusetheCREATEDATABASEcommand
9
• Onceyouhavecreatedthedatabase,youwillnowapplytheUSEcommandtotellthe
systemwhichdatabasetouse
Onceyouhavecreatedadatabase,youwillwanttocreatetableswithinthelargerdatabase:
• NewtablesaredeclaredusingtheCREATETABLEcommand
• Wecanalsosetthenameanddatatypeofeachattribute
• Whencreatingnewtables,wecanspecifyprimarykeysandforeignkeyrelationships
• WecanalsodecidewhetherornotNULLoremptyvaluesareallowed
Inserting Data into a new Database
Onceyouhavecreatedanewdatabase,youarereadytoinsertdata.Thedatamodelwillacta
guidetoloaddataintoanewdatabase.Ifthedatabasebuildswell,itmaymeanthatyouhave
foundtherealbusinessrules.Or,ifyouhavesomeerrors,youmayhavetherealbusinessrules,
butthedatamaybemessy.Finally,ifitbuildswithmanyerrors–thismaybethecasethatthe
businessrulesarenotaccurateandareclosertowhattheywantorthinktheyhave,notwhat
theyuse.Inmanycases,itisusefultogetsampledataandbrowseitduringtheprocessof
buildingthemodel.
SQL Select Queries
SQLSELECTqueryisusedtofetchthedatafromadatabasetable,whichreturnsdatainthe
formofaresulttable.SELECTreturnsasetofattributesinaquery.Inmostapplications,SELECT
isthemostcommonlyuseddatamanipulationlanguagecommand.SELECTstatementsare
constructedfromaseriesclausestogetrecordsfromoneormoretablesorviews.
Clausesmustbeinorder;onlySELECTandFROMarerequired:
• SELECTattributes/columns
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•
•
•
•
•
•
•
INTOnewtable
FROMtableorview
WHEREspecificrecordsorajoiniscreated
GROUPBYgroupingconditions(attributes)
HAVINGgroup-property(specificrecords)
ORDERBYorderingcriterionASC|DESC
DISTINCTreturndistinctvalues
WildcardsinSQL
Mostdatabaseimplementationsofferadditionalregularexpressions–wildcards.Awildcard
charactercanbeusedtosubstituteforanyothercharacter(s)inastring.Regularexpressions
canbeusedtofindrecords,whichmatchcomplexstringpatterns.Forinstance,MySQLhas:
• [list]matchanysinglecharacterinlist,e.g.[a-f]
• [^list]matchanysinglecharacternotinlist,e.g.[^h-m]
Editing a Table
Insomecasesyouwillbefacedwiththeneedtoeditatable.Inthiscaseyouwillusethe
following:
• INSERTisusedtoaddanewrecordtoatablethatcontainsspecificvaluesforasetof
attributesinthattable
• TheUPDATEkeywordisusedtomodifyaspecificvalueorsetofvaluesforasetof
recordsinatable
• DELETEisusedtoremoverecordsfromatablethatmeetaspecificcondition
Learning Objectives
•
•
•
•
•
•
•
BecomemorefamiliarwithSQL.
RecognizedifferentimplementationsofSQLhavedifferencesofwhichtobeaware.
Reviewthedifferentdatatypes.
Learnhowtocreatenewdatabasesandtables.
UnderstandhowtouseaSELECTquery.
Befamiliarwithwildcardsandwhentousethem.
Reviewhowtoeditatable.
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17
Database Conditional, Grouping, and Joins
Summary
Inthenextsectionweexaminehowtodealwithdatabaseconditional,grouping,andjoins.As
wegetfurtherintoSQL,wewillneedtorefineourapproachtomakeouractionsmore
effective.Forexample,wewillneedtonarrowthesetofrecordsthatgetreturnedfroma
query.Wewillalsoneedtomakestatisticalqueriesacrossdifferentgroupingsorrecords.In
addition,wewillneedtosampleororderouroutputresults.Anotherchallengewillinclude
integratingdatafromothersourceswithinourdatabase.Thefollowingreviewwillcoverthese
challengesandothersaswecontinuetoworkwithSQL.
Database Conditional Clauses
Aconditionalclauseisapartofaquerythatrestrictsrowsmatchedbycertainconditions.You
cannarrowSELECTstatementswithconditionalclausessuchasWHEREIN,ortheBETWEEN
keyword.WHEREINstatementsareusedtoidentifyrecordsinatablewithanattribute
matchingavaluefromaspecifiedsetofvalues.TheBETWEENkeywordsareusedtoidentify
recordsthathavevaluesforaparticularattributethatfallwithinaspecifiedrange
WHEREIN:WHEREattributeINisusedtoselectrowsthataresatisfiedbyasetofWHERE
conditionsonthesameattribute.Example:
SELECT*
FROMOffices
WHEREStateIN('CO','UT','TX');
isequivalentto:
SELECT*
FROMOffices
WHEREState='CO'ORState='UT'
ORState='TX'
BETWEENKeyword:Selectrecordswheretheattributevalueisbetweentwonumbersusing
BETWEEN,rangeisinclusiveandalsoworkswithtimeanddatedata.
Null Values
Nullvaluesaretreateddifferentlyfromothervalues;theyareusedasaplaceholderfor
unknownorinapplicablevalues.Ifvaluesareemptyormissing,theyarestoredasNULL.Afew
issuestobeawareofforNULLvalues:
• NULLvaluesevaluatetoNOTTRUEinallcases
• CheckforNULLSusingISandISNOT
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•
WhenaspecificattributemaycontainNULLormissingvalues,specialcaremustbe
takenwhenusingconditionalclauses
Grouping Data and Statistical Functions
OnceyouareabitmorecomfortableworkingwithSQL,youcanstarttoexploresomeofthe
statisticalfunctionsthatareincludedinmanyimplementationsofSQL.Thesefunctionscan
operateonagroupofrecords.UsingtheGROUPBYclausewillreturnasinglevalueforeach
groupofrecords.TofurtherrestricttheoutputoftheGROUPBYclausetoresultswithcertain
conditions,usetheHAVINGkeywords(analogoustotheWHEREclause).
AggregateStatisticalFunctionsinSQL
Commonlyusedfunctionsinclude:
Moreadvancedstatisticalfunctionscanbecreatedusingthebasicstatisticalfunctionsbuiltinto
SQLsuchascalculatingtheweightedaverageorgettingthez-scorevaluesbycombining
differentfunctions.
Sorting and Sampling Data
Youwillalsobefacedwiththeneedtosortandsamplethedata.Severalclauseswillhelpyou
willthatincludingORDERBY,LIMIT,andRAND.
ORDERBY:TheORDERBYclausespecifiesthattheresultsfromaqueryshouldbereturnedin
ascendingordescendingorder
LIMITthenumberofreturnedrecords:ALIMITclauserestrictsthenumberofrecordsthat
wouldbereturnedtoasubset,whichcanbeconvenientforinspectionorefficiency
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Randomlyselectandorderrecords:TheRAND()functioncanbeusedtogeneraterandom
valuesintheoutputortorandomlysampleorrandomlyordertheresultsofaquery.For
instance:
Reordertheentiretable:
SELECT*
FROMtable
ORDERBYRAND();
Randomlyselectasinglerecord:
SELECT*
FROMtable
ORDERBYRAND()
LIMIT1;
Generatearandomnumberintheoutputresults:
SELECTid,RAND()
FROMtable;
Creating New Tables and Aliases
ASKeyword(Aliases):TheASkeywordcreatesanaliasforanattributeorresultofafunction
thatisreturnedinaquery
CREATETABLEAS:UseCREATETABLEwithAStocreateanewtableinthedatabaseusinga
selectquery.Itmatchescolumnsanddatatypesbasedontheresultsintheselectstatement.
ResultsfromaquerycanbeinsertedintoanewtableusingtheCREATETABLEwiththeAS
keyword.Asseeninthefollowing:
CREATETABLEnew_table
AS( SELECTcolumn_name(s)
FROMold_table);
SELECTINTO:ResultsfromaquerycanbeinsertedintoanexistingtableusingaSELECTINTO
clauseifthetablewiththeappropriatestructurealreadyexists.Taketheresultsofaselect
statementandputtheminanexistingtableordatabase:
SELECTcolumn_name(s)
INTOnewtable[INexternaldb]
FROMtable1;
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Joining Multiple Tables
Therelationaldatabasemodelallowsusjoinmultipletablestobuildnewandunanticipated
relationships.Thecolumnsinajoinmustbeofmatchingtypesandalsomustrepresentthe
sameconceptintwodifferenttables.Thiscanhelpustocontextualizeorintegrateatablein
ourdatabasewithdatafromanexternalsource.
Wewanttolearnhowtotakedatafromdifferenttablesandcombineittogether.Thismay
includedatafromotherdatasourcesthatcomplementourown,suchasdemographic
informationforazipcodeorpricestructureforshippingzonesforacarrier.Theprocessof
mergingtwoseparatetablesiscalled“joining”.Joinsmaybedoneonanycolumnsintwo
tables,aslongasthemergeoperationmakeslogicalsense.Seebelowforavisual
representationofjoining:
Joins-visually
Twotableswithshared
field/data
SELECT *
FROM tb1, tb2;
SELECT *
FROM tb1, tb2
WHERE tb1.bg = tb2.bg;
SELECT grey, pink
FROM tb1, tb2
WHERE tb1.bg = tb2.bg; ColumnsinaJOIN
• Theydon’tneedtobekeys,thoughtheyusuallyare
• Joincolumnsmusthavecompatibledatatypes
• Joincolumnisusuallykeycolumn:Eitherprimaryorforeign
• NULLswillneverjoin
36
Types of Joins and Views
Joinfrom3Tables:Joiningthreetablestogetherjustinvolvesoneadditionaljoinbetweentwo
alreadyjoinedtablesandathirdtable.
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JoinTypes
Differenttypesofjoinscanbeusedtomergetwotablestogetherthatalwaysincludeeveryrow
inthelefttable,righttable,orinbothtables.ThefollowingaredifferenttypesofJOIN:
• INNERJOIN:returnsonlytherecordswithmatchingkeys(joinscommoncolumnvalues)
• LEFTJOIN:returnsallrowsfromLEFT(first)table,whetherornottheymatcharecordin
thesecondtable
• RIGHTJOIN:returnsallrowsfromRIGHT(second)table,whetherornottheymatcha
recordinthefirsttable
• OUTERJOIN:Returnsallrowsfrombothtables,whetherornottheymatch(Microsoft
SQL,notMySQL)
• InMySQL,JOINandINNERJOINareequivalent
Views
Viewsarevirtualtablesthatdonotchangetheunderlyingdatabutcanbehelpfultogenerate
reportsandsimplifycomplicatedqueries.Theyarevirtualtablesthatpresentdataina
denormalizedformtousers.Theydonocreateseparatecopiesofthedata(theyreferencethe
dataintheunderlyingtables).Thedatabasestoresadefinitionofaviewandthedatais
updatedeachtimetheVIEWisinvoked.
ThereareseveraladvantagestoVIEWS.Userqueriesaresimpleronviewsconstructedfor
them.Theyoffersalayerofsecuritythatcanrestrictaccesstodatainviewsforusers.Theyalso
providegreaterindependence,meaningthattheuserorprogramisnotaffectedbysmall
changesinunderlyingtables.
Learning Objectives
•
•
•
•
•
•
•
•
•
•
LearnhowtoworkwithSELECTforconditionalclauses.
RecognizetheroleanduseofNULLvalues.
ReviewhowtogroupdatawiththeGROUPBYclause.
IntroducetheexistenceofstatisticalfunctionsinallSQLfunctions.
Recognizehowtoapplyaggregatestatisticalfunctions.
ReviewsortingandsamplingtechniquessuchasORDERBY,LIMITandRAND.
LearnhowtocreatenewtablesandaliasesusingtheASkeyword.
Becomingfamiliarwithjoiningmultipletables.
RecognizethetypesofJOINs.
IdentifywhenandhowtouseVIEWs.
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22
Introduction to Machine Learning
Summary
Inthislessonweexploremachinelearning.Thisincludesidentifyingwhenweneedmachine
learninginsteadofothertechniquessuchasregression.Webreakdownthedifferentclassesof
machinelearningalgorithms.Inaddition,weidentifyhowtousemachine-learningapproaches
tomakeinferencesaboutnewdata.
Review of Regression
Linearregressionusesthevalueofoneormorevariablestomakeapredictionaboutthevalue
ofanoutcomevariable.Inputvariablesarecalledindependentvariablesandtheoutput
variableisknownasthedependentvariable.
• Linearregressionoutputincludescoefficientsforeachindependentvariable.
o Thisisameasureofhowmuchanindependentvariablecontributestothe
predictionofthedependentvariable.
o Theoutputalsoincludesmetricstobeabletoassesshowthemodelfitsthe
data.Thebetterfitofthemodel,thebetteryouareabletomakeaccurate
predictionsaboutnewdata.
• Usingcoefficientscalculatedfromhistoricdata,aregressionmodelcanbeusedtomake
predictionsaboutthevalueoftheoutcomevariablefornewrecords.
Overview of Machine Learning Algorithms
Machinelearningalgorithmsareprimarilyusetomakepredictionsorlearnaboutnew,
unlabeleddata.Thereareseveralclassesofalgorithms:
• Classification:assigningrecordstopre-defineddiscretegroups
• Clustering:splittingrecordsintodiscretegroupsbasedonsimilarity;groupsarenot
knownapriori
• Regression:predictingvalueofacontinuousordiscretevariable
• Associatelearning:observingwhichvaluesappeartogetherfrequently
Supervised vs. Unsupervised Machine Learning
Supervisedlearningusesoutcomevariables,knownaslabels,foreachrecordtoidentify
patternsintheinputvariablesorfeaturesrelatedtotheoutcomevariable.
• Correctanswer,labelisknowninthetrainingdata
• Labelisappliedbyapersonoralreadyexists
• Labeleddataareusedtotrainanalgorithmusingfeedback
• Applyortestthetrainedmodelonnew,unseendatatopredictthelabel
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Supervisedlearningworkflow
Supervisedlearningworkflow
LearningFlow
Training
Training
RawData
Labels
RawData
Labels
Algorithm
(Training)
Algorithm
(Training)
Model
Model
EvaluaBon
MakingPredicBons
MakingPredicBons
Unlabeled
Data
Unlabeled
Data
Model
Model
PredicBon
PredicBon
Unsupervisedlearningworkflow
LearningFlow
EvaluaBon
16
Inunsupervisedlearning,theoutcomevariablevaluesareunknown,therefore
RawData
relationshipsamongtheinputvariablesareusedtoidentifypatternsofclustersof
records.
16
• Findspreviouslyunknownpatternsinthedatawithoutlabelsorguidance
Algorithm
• Notraining/testing/validatingprocessbecausecorrectanswerisunknown
Model
Model Quality
Machinelearningmodelsshouldbetrainedonanunbiasedsetofdatathatis
Produc<on
representativeofthevarianceintheoveralldataset.Biasquantifiesthelackof
abilityofamodeltocaptureunderlyingtrendinthedata.Morecomplexmodels
decreasebiasbuttendtoincreasevariance.Variancequantifiesamodel’ssensitivitytosmall
changesintheunderlyingdataset.
• Ideallywantlowbiasandlowvariance,butthereisatradeoffbetweenthetwo
quantities
• Ifthereisabiasinthetrainingdataoriftoomanyfeaturesareincludedinamodel,the
modelisatriskofbeingoverfit.Inoverfitmodels,thecoefficients,knownas
parameters,willnotbegeneralizableenoughtomakegoodpredictionsfornewrecords.
• Alargeandrepresentativesampleofthelabeleddatashouldbeusedtotrainthe
model,theremainderisusedfortesting.
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24
Overfitting vs underfitting
•
•
Underfitting–modelistoosimple,highbiasandlowvariance
Overfitting–modelistoocomplex,lowbiasandhighvariance
o Overfittingisamorecommonpitfall
o Temptingtomakemodelsfitbetterbyaddingmorefeatures
o Resultsinamodelthatisincapableofgeneralizingbeyondthetrainingdata
Learning Objectives
•
•
•
•
•
Beintroducedtomachinelearning
Becomefamiliarwithdifferenttypesofmachinelearningalgorithms
Beabletodifferentiatesupervisedandunsupervisedlearningandtheirprocesses
Recognizemodelqualityandthetradeoffsbetweenbiasandvariance
Learnhowtoidentifywhenamodelisoverorunderfit
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25
Machine Learning Algorithms
Summary
Inthislessonwearegoingtodivedeeperintomachinelearningalgorithms.Eachmodelhas
differentpropertiesandisbestfordifferenttypesoftasks.Wereviewhowtocomparethem
withperformancemetrics.Weneedtobeabletogrouprecordstogetherwithoutlabelsto
informpredictionusingunsupervisedclassification.Inaddition,wereviewcapabilityto
confidentlyreducethenumberoffeaturesincludedinananalysiswithoutlosinginformation.
Thelessonalsointroduceshowtocomparepredictoraccuracyandtestforsensitivityand
specificity.
Dimensionality reduction
Dimensionalityreductionisatermforreducingfeaturesincludedinanalysis.Itisoftenneeded
foranalysiswithmanyfeatures.Tryingtoreducedimensionalityrandomlyormanuallyleadsto
poorresults
• Resultsneedtobeinterpretedbyhumans,shouldbetractable
• Increasingthenumberoffeaturesincludedincreasestherequiredsamplesize
• Featuresshouldnotbeincludedordiscardedfromanalysisbasedoninstinct
o Dimensionalityreductiontechniquesshouldbeemployed,suchasprincipal
componentanalysis.
• Summarystatisticsareameansofdimensionalityreduction
Principal component analysis (PCA)
PCAisamathematicalapproachtoreducedimensionalityforanalysisorvisualization.It
exploitscorrelationstotransformthedatasuchthatthefirstfewdimensionorfeaturescontain
amajorityoftheinformationofvarianceinthedataset.PCAdetermineswhichvariablesare
mostinformativebasedonthedistributionofdataandcalculatesthemostinformative
combinationsofexistingvariableswithinthedataset.PCAworkswellfordatasetswithhigh
dimensionality.
• Noinformationislost,firstfewcomponentsholdmuchoftheinformation
• Samepremiseaslinearregressionexceptwithoutadependentvariable
o Linearregressionsolutionisthefirstprincipalcomponent
o Disregardingtheinformationdescribingtheprincipalcomponent,PCAcalculates
thesecondmostinformativecomponent,thenthethird,andsoon
• Linearcombinationsformasetofvariablesthatcanbeusedtoviewthedata–new
axes
• Componentsarerankedbyimportance,soallbutthefirstfewcanbediscarded,leaving
onlythemostimportantinformationwithveryfewcomponents
• Thecoefficientsinthetablegivetheproportionofeachoftheoriginalvariablesthat
wentintoeachcomponent
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26
•
•
Relativesigns+/-indicatethattwovariablesarepositivelynegativelycorrelatedinthat
particularcomponent
Thecomponentsaredifficulttointerpretusingonlythecoefficientvalues,plottingoften
improvesunderstanding
PC1=(a*var1+b*var2+c*var3+…)
PC2=(d*var1+e*var2+f*var3+…)
PC3=(g*var1+h*var2+i*var3+…)
Clustering
Anotherwayofthinkingaboutdimensionalityreductionishowcloseeachpointistoother
points.Theideaistoseparatedatapointsintoanumberofclustersthathavelessdistance
betweenthepointsinternallythantootherclusters.Clusteringcanbehelpfultoidentifygroups
ofrecordsthathavesimilarcharacteristicstooneanother.Whendataisunlabeled,clustering
canbeusedtogrouprecordstogetherfordeeperinspection.Upondeeperinspectionofthe
recordsineachcluster,userscanunderstandthepatternsthatleadtorecordsbeinggrouped
together,andalsoidentifyreasonsforrecordsbeinggroupedseparately.
K-means clustering
k-meansclusteringstartswithselectingthenumberofclusters,k.kcluster-centersareplaced
randomlyinthedataspaceandthenthefollowingstagesareperformedrepeatedlyuntil
convergence.K-meansdoesnotdeterminetheappropriatenumberofclusters,thisissetbythe
userbasedonintuitionorpreviousknowledgeofthedataThealgorithmcanterminatewith
multiplesolutionsdependingoninitialrandompositionsofcluster-centersandsomesolutions
arebetterthanothers.
• Datapointsareclassifiedbythecentertowhichtheyarenearest
• Thecentroidofeachclusteriscalculated
• Centersareupdatedtothecentroidlocation
Classifications
•
•
•
•
ClusteringandPCAallowuserstoseepatternsinthedata,whichisthebestthatcanbe
donebecausetherearenolabelstoguidetheanalysis
Withsupervisedlearning,thelabelisincludedinthelearningprocess:
o Unsupervised:whatfeaturesaremostimportantorinteresting?
o Supervised:whatfeaturesaremostinformativeaboutthedifferencesbetween
thesegroups?
Classificationmethods:eachrecordfallsintosomecategoryorclass,predictthe
categoryofanewrecordbasedonvaluesofotherfeaturesintherecord
Regressionmethods:onevariabledependsonsomeorallofothers,predictthevalueof
thedependentvariablebasedonthevaluesoftheindependentvariables
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Classification Trees
Classificationtreessplitdatatofindoptimalvaluesforfeatures,usedtosplitdatabyclass.Tree
diagramsshowtheclassmakeupofeachnode,andtherelativenumberofdatapointsthat
reacheachnode
• Treepruning
o Treepruningremovesrulesassociatedwithoverfittingfromthetree
o Thenewtreemissesafewpointsclassifiedcorrectly,butcontainsonlymeaningful
rules,moregeneralizabletonewdata
Naïve Bayes classifier
•
•
•
TheNaïveBayesalgorithmconsidersthevalueofeachfeatureindependently,foreach
record,andcomputestheprobabilitythatarecordfallsintoeachcategory
Next,theprobabilitiesassociatedwitheachfeaturearecombinedforeachclass
accordingtoBayes'ruletodeterminethemostlikelycategoryforeachnewrecord
Almostcompletelyimmunetooverfitting-Individualpointshaveminimalinfluence;
Veryfewassumptionsaremadeaboutthedata
Random forest
Randomforestisanensembleclassifierthatusesmultipledifferentclassificationtrees.Trees
aregeneratedusingrandomsamplesofrecordsintheoriginaltrainingset.Accuracyand
informationaboutvariableimportanceisprovidedwiththeresult.
• Nopruningnecessary
• Treescanbegrownuntileachnodecontainsveryfewobservations
• Betterpredictionthanclassification
• Noparametertuningnecessary
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28
Comparing predictor accuracy
Cross - validation
•
•
•
Modelsshouldbegoodatmakingclassificationsofunlabeleddata,notdescribingdata
thatisalreadyclassified.
Randomlydividedataintoatrainingsetandatestset
o Hidetestsetwhilebuildingthetree
o Hidetrainingsetwhilecalculatingaccuracy
o Computedaccuracyrepresentsaccuracyonunseendata
Techniquesareavailabletodothismultipletimes,ensuringeachrecordisinthetestset
exactlyonce,e.g.k-folds
Comparing models
•
•
Severalstandardmeasuresofperformanceexist,canrunmultiplemodelsandcompare
metrics:
o Accuracy
o Precision
o Recall
o Andmore
Applicationdriveswhichperformancemetricsaremostimportantforagiventask
Sensitivity and specificity
Sensitivityandspecificityarestatisticalmeasuresoftheperformanceofaclassificationtest.
Sensitivitymeasurestheproportionofpositivesareidentified.Specificitymeasuresthe
proportionofnegativesthatareidentified.Seeexamplebelow:
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29
The ROC Curve
•
•
•
•
TheReceiverOperatingCharacteristic(ROC)curveplotsthetruepositiverate
(Sensitivity)versusthefalsepositiverate(100-Specificity)fordifferentcut-offpoints
Eachpointonthecurverepresentsapairofsensitivity/specificityvaluescorresponding
toaparticulardecisionthreshold
Atestwithperfectdiscrimination(nooverlapinthetwodistributions)hasanROCcurve
thatpassesthroughtheupperleftcorner(100%sensitivity,100%specificity)
TheclosertheROCcurveistotheupperleftcorner,thehighertheoverallaccuracyof
thetest
Learning Objectives
•
•
•
•
•
•
Befurtherintroducedtomachinelearningalgorithmsandhowtoworkwiththem
Becomefamiliarwithdimensionalityreductionandwhenandhowtouseit
Recognizewhentouseclusteringasanapproachtodimensionalityreduction
Reviewdifferentclassificationmethodssuchasclassificationtressandrandomforest
Learnhowtocomparepredictoraccuracy
Becomefamiliarwithsensitivityandspecificityasindicatorsofabinaryclassification
test
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30
Supply Chain Systems - ERP
Summary
Inthisnextsegment,weexploresupplychainITsystems.Becausesupplychainsareessentially
madeupofthreeflows:information,material,andmoney–ITsystemssupporttheinformation
flow.Forexample,inasupermarket,theyhavetodealwithdifferenttypesofsupplychaindata
suchassupplierinventory,facilitymanagementandpayroll,sales,andexpiredandobsolete
inventory.Therearemanydailytransactionsinasupermarketthatneedtobecapturedand
ensuredforconsistencyandtimeliness.Thatinformationneedstobesomehowtranslatedinto
usableinformationforbusinessdecisions,andthentheseobjectivesneedtobeefficiently
achieved.Theamountofinformationfortransactionsperweekinasinglesupermarketcan
numberinthemillions.Thisisforasinglestore.
Onanenterpriselevel,companiesneedsystemsthathelpthemmanageandorganizethis
informationforuse.Whilesupplychainsarealwaysportrayedasneatandlinearsystems,the
realityismuchdifferent,aswehavelearnedoverthepreviouscourses.Flowsmoveupand
downthechainandthroughmanypartnersuntiltheyreachtheirfinaldestination.Supply
chainsneedITsystemsbecausewhileteamsmaysitindifferentfunctionalunitstheyfrequently
needtoshareinformation.Inaddition,manydifferentfirmsinteractinthesupplychain,they
needsystemstocarrythatinformationbetweenthem,thishelpsde-silothesupplychain.
Thereneedstobecoordinationacrossfunctions,whichistheessenceofsupplychain
managementandcanbefacilitatedwithsystemslikeEnterpriseResourcePlanning(ERP).
Supply Chain IT Systems
SupplychainsneedITsystemsbecausetheyarelarge,complexandinvolvemanyplayers.They
oftenbecomeintertwinedandindividualactorsimpactothers.Decision-makingisbasedon
commondataandinteractionwithotherfunctionsinafirm.AndsupplychainsneedITsystems
becausesupplychainsrequirecommunicationforsomanyinteractionsB2B,B2C,M2M,etc.
(B2B=businesstobusiness,B2C=BusinesstoConsumer,M2M=machinetomachine)
EnterpriseResourcePlanning(ERP)systemsserveasageneralledgerandcentraldatabasefor
allfirmactivity.ThenextareSupplyChainPlanningSystems.Thesesystemsareprimarilyfor
productionplanningandscheduling,demandplanningandproductlifecyclemanagement.The
lastareforSupplyChainExecution;whicharetransportationandwarehousemanagement
systemsandmanufacturingsystems.ThefirstwewilltackleareEnterpriseResourcePlanning
systems.
Enterprise Resource Planning
InthefollowingsectionwecoverwhyfirmsuseERPs;thecorefunctionsofERPs;dataneeded;
communicationsofthesystems;andstrategicbenefitsofanERP.MostfirmshaveanERP
becausemanyfunctionsinafirmsuchassales,inventory,production,finance,distribution,and
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humanresourceshavesiloeddatabases.WithacentralizedERP,thesedatabasescanmore
easilybeexchangedandshared.
BenefitsofERPallowenterprisestoorganizeprocessesanddatastructure,integrate
informationintounifiedrepository,makedataavailableformanyusers,eliminateredundant
systemsanddata,reducenon-valueaddedtasks,standardizeprocessdesigns,aswellasbe
moreflexible.TherearesignificantdrawbackstousingERP,theseinclude:significant
implementationtimeandmaintenancethatcomeatacost,dataerrorsripplethroughsystems,
competitiveadvantagecanbedampened,firmrelianceonasinglevendor,shortageof
personnelwithtechnicalknowledgeofsystem,andhighimpactofdowntimeofsaidsystem.
ERP Core Functions
MostERPSystemssharethesamecorefunctions.Theytietogetherandautomateenterprisewidebasicbusinessprocesses:
CustomerManagementisthefacetoconsumersandservesthefollowingfunctions:
• enablesorderentry,orderpromising,openorderstatus
• allowsmarketingtosetpricingschemes,promotions,anddiscounts
• providesreal-timeprofitabilityanalysis,and
• permitsorderconfiguration,customerdeliveryschedules,customerreturns,tax
management,currencyconversion,etc.
Manufacturingisthefacetoproductionandservesthefollowingfunctions:
• includesMRPprocessing,manufacturingorderrelease,WIPmanagement,cost
reporting,shopfloorcontroletc.,
• providesrealtimelinkageofdemandtosupplymanagementenablingrealtime
Available-to-Promise(ATP)&Capable-to-Promise(CTP),and
• servesasprimaryinterfaceto“bolt-on”advancedplanningandschedulingoptimization
modules.
Procurementisthefacetosuppliersandservesthefollowingfunctions:
• integratesprocurementwithsuppliermanagement,
• facilitatespurchaseorderprocessing,deliveryscheduling,openordertracking,
receiving,inspection,andsupplierperformancereporting,and
• createsrequestsforquotation(RFQ)
• managesnegotiationandpricingcapabilities.
Logisticsisthefacetointernalandexternalsupplychainandservesthefollowingfunctions:
• runstheinternalsupplychainforenterprise,
• providesconnectivitytoremotetradingpartners(3PLs,carriers,etc.),
• handlesdistributionchannelconfiguration,warehouseactivitymanagement,channel
replenishment,planning,distributionordermanagement,etc.,and
• servesasprimaryinterfaceto“bolt-on”warehouseandtransportationmanagement
systems(WMSandTMS).
ProductDataisthefacetoallmaterialandservesthefollowingfunctions:
• describesproductsenterprisemakesand/ordistributes,
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containsproprietarydataoncosts,sources,engineeringdetails,dimensions,weight,
packaging,etc.,
• interfaceswithinventory,manufacturing,andproductlifecyclemanagement,and
• sometimesincludedinpartnercollaborationsinordertocompresstimetomarketof
newproducts.
FinanceisthefacetotheCFOandservesthefollowingfunctions:
• strongsuitofmostERPs(butalsoadoubleedgedsword!),
• providesreal-timereportingofalltransactionsresultingfrominventorymovement,
accountsreceivable,accountspayable,taxes,foreigncurrencyconversions,andany
otherjournalentries,and
• supportsdetailedreportingandbudgetingcapabilities.
•
ERP Data
TherearethreetypesofERPData:
Organizationdata:representsandcapturesthestructureofanenterprise.
Masterdata:representsentities(customers,vendors)withprocesses.Itisthemostcommonly
used.Butbecausespecificprocessesusematerialsdifferentlyandspecificdataneedsdifferby
processes–thisaddstocomplexityofmasterdataneeds.Materialtypescanbeindifferent
statesandcanbegroupeddifferentlybasedonfirmneeds.
Transactiondata:reflectstheoutcomeofexecutingprocesssteps.Itcomesinorganizational,
masterandsituationaldata.Transactiondocumentsincludepurchaseorders,invoices,etc.
ERP Communication
Business-to-Business(B2B):Commercetransactionsbetweenmanufacturers,wholesalers,
retailers.Eachbusinessrepresentsalinkinthesupplychain.
Business-to-Consumer(B2C):Saletransactionsbetweenfirmsandend-consumers.Thevolume
ofB2BtransactionsismuchgreaterthanB2C.
AcceleratingandvalidatingB2BandB2Ctransactions:ForB2Bthisisachievedthrough
ElectronicDataInterchange(EDI).ForB2Cthisisachievedthroughawebsiteandemail.
ElectronicDataInterchange(EDI):“Thecomputer-to-computerinterchangeofstrictly
formattedmessagesthatrepresentdocumentsotherthanmonetaryinstruments.”Thereisno
humaninterventionintheprocess.
ERPsystemscan“communicate”viaEDI,sharingnearreal-timeinformation.Seefigurebelow.
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ERPCommunica-on
§  B2BEDIexample:
PurchaseOrder
OrderConfirma-on
SAP
Data
Format
OrderCancella-on
BusinessX
Gateway
ETA
OrderCancella-on
BusinessY
Gateway
Oracle
Data
Format
ASN
OrderReceipt
§  ERPsystemscan“communicate”viaEDI,sharingnearreal--meinforma-on.
The§  Value
of ERP for SCM
ThedataisusuallytranslatedandvalidatedtobeimportedintoanERPsystem.
TherearethreeimportantvaluesofERPforsupplychainmanagement:reductionofthe
§  AnyinfofilecanbesharedgivenappropriateERPfieldstocaptureanddisplayits
bullwhipeffect,enablingwidespreadanalytics,andextendingtheenterprise.
content.
§  Whatotherinfowouldbusinesseswanttoshare?
Reducing the Impact of Bullwhip Effect
MIT Center for
OneofthekeyvaluesofanERPsystemisreducingorpreventingtheBullwhipEffect.The
24
Transportation & Logistics AdaptedfromOmarElwakil(2016)
BullwhipEffectisphenomenonwhereinformationdistortionleadstoincreasingorder
fluctuationsintheupstreamsupplychain(forecast-drivensupplychains).Itisdrivenbyseveral
behavioralcauseslikeoverreactiontobacklogsandlackoftransparency.Therearealsomany
operationalerrorssuchasforecastingerrors,lead-timevariability,andpromotions.
ERPcanreducetheimpactoftheBullwhipEffectbyextendingvisibilitydownstreamto
customerdemandandupstreamtoparticipantsenablingcollaborationandinformation
sharing.Italsofacilitatespointofsalecapturingandhelpsreducebatchsizeanddemand
variabilitythroughsmallerandmorefrequentorders.
Enabling Analytics
ERPsystemsplayakeyroleinenablinganalytics.Theyareprimarilyretrospective,serveasthe
ledgerofthefirm,andprovidetheCFOwithfinancialsnapshots.Theyalsoenableotherforms
ofanalyticsforBusinessIntelligence(BI):whichtransformsrawdataintomeaningful
informationtoimprovebusinessdecision-making.Thesecanbedescriptive,predictive,and
prescriptive.
Extending Enterprise
WhileERPsystemsareprimarilyusedinintra-firmprocessmanagementtoconnectvarious
departmentsandprovideaccesstodata,theyalsoserveanextendingfunctionforbetter
connectionwithpartners.ERPsserveavalueinconnectingEndtoEndSupplyChainswith
betterconnectionsacrossSCparticipants,providingsharedunderstanding,reducing
coordinationandmonitoringcosts,andrespondingquicklytomarketfeedback.
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Learning Objectives
•
•
•
•
•
•
IntroductiontosupplychainITsystems,theirvalue,application,andconstraints.
ReviewERP,itssetupfunctionality,andapplications.
RecognizecorefunctionsofERP.
BefamiliarwithdatahouseinERPsystems.
Reviewhowthatdataisusedtofacilitatecommunication.
UnderstandsomeofthevalueofERPsystemsforsupplychains.
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Supply Chain Systems - Supply Chain
Modules
Summary
InthisnextsegmentwereviewdifferentsupplychainmodulesasasubsetofsupplychainIT
systems.TounderstandwherewearenowwithsupplychainITsystemsweneedtoreviewthe
evolutionofsupplychaintools.Wejourneyfromthe1960-70’swiththeBillofMaterials
Processor,mainframesbaseddatabasesystems,andmaterialrequirementsplanning(MRP)to
the1980’swiththesecondcomingofMRPthataddedfinanceandmarketing,Just-In-Time
manufacturingmethodology,expansiontootherfunctions,andtheprecursortotheERP
systemsoftoday.Inthe1990s,mostMRPsystemswereabsorbedintoERPsuites;therewas
theintroductionofAdvancePlanningSystems(APS),andwideradoptionofERPsystems.Inthe
2000s,manyofthesesystemsadoptedweb-basedinterfaces,improvedcommunication,and
adoptedsharedorcloudbasedsolutions.Therewasalsoamajorconsolidationofsupplychain
softwarevendorsandexpansionofERPsystemstoincludeSCM.
Nowasweexplorehowtofurtherextendtheenterpriseanditsabilitytoadequatelymanage
itsinformationonitsownandtogetherwithothercompanies,manyfirmsuseaseriesofIT
modules.ThesesystemsaresometimesapartofERP,maybestandaloneapplications,orcan
bepartofalargersupplychainecosystem.Wewillreviewtwomainfunctionalitiesincluding
AdvancePlanningSystems(APS)andExecutionApplications.AdvancedPlanningSystems(APS)
arelongrange,optimizationbaseddecisionsupporttoolswhileexecutionapplicationsinclude
WarehouseManagementSystems(WMS),TransportationManagementSystems(TMS),and
ManufacturingExecutionSystems(MES).
Planning vs. Execution
Althoughplanningmodulesseektoenablefutureplanningandenablingefficientprocesses,
thereisoftenagapbetweentheplanningandexecutiontasks.Thefigurebelowillustratesthis
Planning vs. Execution
gap.
Consists of a continuum of tasks, but . . .
ROA
Impact
Supply
Chain
Strategy/
Network
Design
Execution
Tasks
Tactical
Transportation
Transportation
Modeling
Shipment
Procurement
Consolidation
& Carrier
Selection
Planning Tasks
Fleet
Routing/
Scheduling
. . . there is a gap!
MIT Center for
Transportation & Logistics
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Questions, Approaches, and Technologies Change based on timeframe
Questionscanbestrategicsuchas:“WhatcarriersshouldIpartnerwithandhow?”“How
shouldIflowmyproducts?”ortheycanbetacticalsuchas:“HowcanIquicklysecureratesfor
anewDC/plant/lane?”“Whatlanesarehavingperformanceproblems?”oroperational:
“WhichcarriershouldItenderthisloadto?”“HowcanIcollaborativelysourcethisweeks’
loads?”
Thetimeframealsodrivestheapproach.Forinstanceinthestrategicface–acompanywillbe
establishingaplanandstrategy,haveeventbasedenablementandcompletenon-routine
analysis.Inanoperationaltimeframetheywillbeexecutingthestrategicplan,operateon
transactionbasedrulesandprocesses,andhaveautomatedactions.
Andtechnologiesalsoalignwithtimeframes.Forinstance,strategictimelinewillallowfor
analysisenginestoolslikeoptimization,simulationanddataanalysisandcommunicationvia
theweb,fileexchangeandremoteaccess.Thetacticaltimelineallowsforthesameanalysis
andcommunicationtechnologieswhiletheoperationaltimelineallowsforcommunicationbut
alsoworkflowsoftwaresuchascompliancetracking,rules,andtransactionprocessing.
Advanced Planning Systems
Wenowtakeacloserlookatadvancedplanningsystemsthatareprimarilyusedasdecision
supportsystems.Theytypicallyincludefunctionalityfornetworkdesign,demandplanning,
productionplanning,productionscheduling,distributionplanning,andtransportationplanning.
AdvancedPlanningSystemsutilizelargescalemixedintegerlinearprograms(MILPs)and
sometimessimulation.
Planning Horizons
AdvancePlanningSystemshelpwithplanninghorizons.Thefollowingprovidearoughguideline
buteachfirmdiffersanditisuniquetospecificindustries.:
• 3monthsout–MasterProductionSchedule(MRP,DRP)
o <4weeksout-FrozenMPS
o 5to8weeksout–SlushMPS–somechangesallowed(+-10%)
o >8weeksout–WaterMPS–morechangesareallowed(+-30%)
• 3-18monthsout–AggregatedPlanning
• >18monthsout–LongRangePlanning–NetworkDesign,etc.
Flow
Inputs(fromERPorothersystems):Currentcosts,manufacturingandstoragecapacities,
consensusforecast,salesorders,productionstatus,purchaseorders,andinventorypolicy
recommendations,etc.
DecisionProcess:Largescaleoptimization(MILP)acrossmultiplefacilitiesandtimehorizonsin
asingleplanningrun;unconstrained,constrained,andoptimalplans
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Outputs:Demandforecastandplanformeetingdemand;afeasibleproductionplanforfuture
periodstoincludeallocationofproductiontoplants;allocationoforderstosuppliers;
identificationofbottlenecks;RootCauseAnalysis.
Transportation Management Systems (TMS)
TMSissoftwarethatfacilitatesprocurementoftransportationservices,short-termplanning
andoptimizationoftransportationactivities,assets,andresources,andexecutionof
transportationplans(Gonzalez2009).Itisoftengeographicandmodespecific.Thecore
functionsofTMSare:transportationprocurement;modeandcarrierselection;carrier
communication;routingguidegenerationandmaintenance;fleetmanagement;audit,
payment,andclaims;appointmentscheduling;yardmanagement;androuteplanning.
Transportation Execution
TheTMSservesastheinterfacetothecarrierswhileconnectingtheOrderManagement
System(OMS),PaymentSystems,andtheERP.Itsmainobjectiveisto:moveproductsfrom
initialorigintofinaldestinationcosteffectivelywhilemeetingthelevelofservicestandardsand
executingtheplanusingtheprocuredcarriers.Thisisbrokendowninphasesbelow:
PLAN:CreateShipmentsfromOrders
EXECUTE:SelectandtendertoCarriers
MONITOR:VisibilityofthestatusofShipments
RECONCILE:AuditinvoicesandpayforTransportation
TherearemanyconsiderationstobemadeinTMSsuchas:
§ Howdoordersdrop?BatchedvsContinuous?
§ Howmuchtimeisallowedbetweendropandmust-ship?Weeks?Days?Hours?
Minutes?
§ Whatpercentageoforderschangeafterrelease?
§ Howdotheychange?Quantity?Mix?Destinations?Timing?
§ Whatisthelengthofhaul?
§ Howmanyordersare“inplay”atanytime?
Therearealsokeydecisionslikecarrierselectionandloadbuilding.
TMS Carrier Communication & Selection
UsefulEDITransactionSets
• 204–MotorCarrierLoadTender:Usedbyshipperstotenderanofferforashipmentto
afulltruckloadmotorcarrier.Itmaybeusedforcreating,updatingorreplacing,or
cancelingashipment.
• 990-ResponsetoaLoadTender:Usedbymotorcarrierstoindicatewhetheritwillpick
upashipmentofferedbytheshipper
• 214-TransportationCarrierShipmentStatusMessage:Usedbycarrierstoprovide
shippersandconsigneeswiththestatusoftheirshipments.
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Carrier Selection
Exampleofcarrierselection
Carrier C
Continuous Move
Primary
Carrier A
Spot
Carrier A
Carrier E
Spot
Carrier B
Carrier B
Carrier B
Carrier B
Types of Capacity
Dedicated
Primary - Contracted Carrier
Dedicated Fleet
Continuous Move
Spot Carrier
Carrier D
Spot
15
MIT Center for
Transportation & Logistics
LinkingApproaches
Approaches Must Be Linked
Tier III
Spot execution –
highly variable
Tier II
How do I select
each carrier?
Increased flexibility
in execution
Dynamic
Tier I
Uses strategic
routing guide
Flexible Assmt
Dynamic Carrier
Selection
Dynamic Pricing
in Private
Exchange
III IV
I
Static
Strategic
Lane Assmt
Contract
II
Strategic
Lane Assmt
w/ Tier Pricing
Dynamic
How do I price each load?
MIT Center for
Transportation & Logistics
26
Warehouse Management Systems & Automation
WMSisasoftwaresystemthatfacilitatesallaspectsofoperationswithinawarehouseor
distributioncenterandintegrateswithothersystems.Itisnotthesameasinventory
managementsystems;WMScomplementsIMS.ExamplesofthebenefitsofaWMSinclude:
real-timestockvisibilityandtraceability,improvedlaborproductivity,andimprovedcustomer
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service.Someofthesebenefitsarecloselytiedtoautomationofmaterialhandlingand
paperlessdeviceinterfaces.
ExamplesofWarehouseAutomationinclude:
Automaticidentificationtechnologies:Barcodesandbarcodescanners,radiofrequencytags
(RFID)andantennae,smartcardsandmagneticstripes,visionsystems.
Automaticcommunicationtechnologies:Radiofrequencydatacommunications,synthesized
voice,virtualdisplays,picktolight/voicesystems
Automatedmaterialhandlingtechnologies:Carousels,conveyors/robotics,flowracks,AS/AR
Systems
WMS Software Components
OrderProcessing
• Orderchecking&batching
• Allocation
• Auto-replenishment
Receiving
• ASNplanning
• Inboundtracking
• Deliveryappointmentscheduling
• POverification
• Returnsprocessing
Put-Away
• Palletizing
• Zoningandslotting
• Random/directedputaway
• Routingforputaway&replenishment
Picking
• Batch/Wave/Zone/Directedpicking
• Carton/palletselect
• Assembly/kitting
• Pick-to-light/voice
Shipping
• Palletsequencing&Loadplanning
• Palletlayering
• Trailermanagement
LaborManagement
• Individual/teamperformancemgmt
• Laborscheduling
• Timestandards
EquipmentSupport
• Interfacetoautomatedequipment
• Equipmentmaintenance
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Manufacturing Execution Systems
MESisasoftwaresystemthatmanagesandmonitorsallwork-in-process(WIP)inthe
productionprocess.ItisintegratedwiththeERPtomanagetheexecutionofreleaseof
productionorderstofinishedgoodsdelivery,triggersupplychainreplenishments,andenhance
producttraceabilitythroughmanufacturing.
ThefunctionalityofaMESinclude:
• Machinescheduling
• Processmanagement
• Documentcontrol
• Labormanagement
• Inventorymanagement
• Product(WIP)tracking
• Performanceanalysis
• Labormanagement
• Qualitymanagement
• Productionreporting
Learning Objectives
•
•
•
•
•
Becomefamiliarwithsystemsthatarecommoninsupplychainsthatextendthe
enterprise.
DifferentiatebetweenAdvancedPlanningSystemsandExecutionSystems.
Recognizethegapsinplanningvs.executionandthetimeframesembeddedinboth.
ReviewAdvancedPlanningSystems,theiruseandapplication.
BecomefamiliarwiththemainexecutionsystemsinSCsuchasTMS,WMS,andMES.
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Supply Chain Systems - Software Selection
& Implementation
Summary
Aswehavejourneyedthroughvarioustypesofsupplychainsystems,wewillnowcoverthe
processofsoftwareselectionandimplementation.Asfirmsareintheprocessofselectingtheir
supplychainsystemstheywillneedtobeawareofvariousfactorsthatwillguidetheirdecision
ofwhethertoselectthesystemornot.Sowenowdiscusstheprocessofsoftwareselection
andevaluationcriteria.Whileselectingtheappropriatesoftwaresystemcanbechallenging,
implementationisfarmoredifficult.Theprocessofimplementationcanbelongandcostly,
usingadditionalresources.Inthislesson,wecovergeneralguidelinesonwhattobeprepared
forwhenimplementingsoftwaresystems.
Architecture
Evolution of Architecture
Tounderstandwheresupplychainsystemsstandnow,itishelpfultounderstandtheevolution
ofthearchitecturestartinginthe1970’s.Thefollowingarethevariousformsofarchitecturefor
thelastfiftyyears:
• Mainframe(1970s)
• PersonalComputers(mid-1980s)
• Client-Server(late80stoearly90s)
• WideWebandWeb2.0(mid-90stopresent)
• CloudorPost-PC(todayandbeyond)
Todaythereareavarietyofsoftwaresystemsavailabletobusinesses.Intermsofarchitectural
format,theycanchoosebetween“OnLocation”or“OnPremise”–meaningthatthefirmshost
thesoftwareintheirownfacilitiesorontheirhardwareandwithintheirownfirewall.However,
companiesareincreasinglyoptingforcloudcomputingoptions.Thismeansthattheyhave
severaldeploymentmodelsavailabletothem.
Cloud Computing
Ascloudcomputingbecomesincreasinglymorepopular,thereareavarietyofofferingsthat
canbetailoredtofirmneeds.TheyareInfrastructureasaService(IaaS),PlatformasaService
(Paas),andSoftwareasaService(Saas).Wediscusseachformataswellasbenefitsbelow:
InfrastructureasaService(IaaS):Inthisformat,thethirdpartyprovidesthefirmwiththe
computinginfrastructure,physicalorvirtualmachinesandotherresources.Firmownsand
managesthesoftwareapplication.Thebenefitsofthisare:
• Noneedtoinvestinyourownhardware
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•
•
Infrastructurescalesondemandtosupportdynamicworkloads
Flexible,innovativeservicesavailableondemand
PlatformasaService(PaaS):Inthisformat,thethirdpartyprovidesfirmcomputingplatforms
toincludeoperatingsystem,database,webserveretc.Firmownsandmanagesthesoftware
application.Thebenefitsofthisare:
• Developapplicationsandgettomarketfaster
• Deploynewwebapplicationstothecloudinminutes
• Reducecomplexitywithmiddlewareasaservice
SoftwareasaService(SaaS):Inthiscase,thethirdpartyprovidesfirmwithaccesstothe
applicationsoftwareandhandlesinstallation,setup,maintenance,andrunning.Firmis
chargedbyuse.Benefitsinclude:
• Youcansignupandrapidlystartusinginnovativebusinessapps
• Appsanddataareaccessiblefromanyconnectedcomputer
• Nodataislostifyourcomputerbreaks,asdataisinthecloud
• Theserviceisabletodynamicallyscaletousageneeds
Whiletherearemanybenefitstocloudcomputing,therearewidespreaddisadvantagesof
cloudcomputingthatincludebutarenotlimitedto:vendoroutages,unrestrictedgovernment
access,security&privacyrisks,andkeydataandprocessesrequirenetworkaccess.
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Software Selection Sources
Therearedifferentsourcesofsoftwarethatfirmsneedtobeawareof.Theseincludea
customizedin-housesystemdesignedforabusiness,anERPexpandedsystemwithadditional
bellsandwhistlestailoredforacompany,bestofbreedsolutions(ofmarketsolutions),and
bestofbreedplatforms.Thesearediscussedinfurtherdetailinthechartbelow:
ProsandConsforSo3wareSources
Source
Customized
In-House
System
ERP
Expanded
Systems
Advantages
Disadvantages
•  Bestfittothefirmanditsprocesses.
•  Excep7onallydifficultand7me
consumingtodevelop
•  Mostexpensivetotalcostofownership
•  Difficulttomaintain
•  Canresultin“inwardlooking”solu7on
•  Rela7velyfastimplementa7on
•  Lessexpensivethanin-house
customiza7on
•  EfficientfromITperspec7ve
•  EasiertoupgradewithERP
enhancements
•  Tendstobeinflexibleintermsof
process
•  Couldrequirechangeinbusiness
processes
•  Notguaranteedtobebestsolu7on
approach
BestofBreed •  Bestperformingmarketsolu7onforeach •  Difficulttointegratedifferentsystems
Solu7ons
func7on
•  Canhaveslowperformance
•  Requirestheuseofmiddleware
betweentheapplica7ons
•  Upgradingindividualcomponentscan
causerippleeffectproblems
BestofBreed •  Verygood,ifnotbest,solu7onforeach •  Requirestheuseofmiddleware
Plaborms
func7onwitheasierintegra7onbetween
betweentheapplica7ons
individualmodules
MIT Center for
Transportation & Logistics
Outsourcing
14
Thereisalsotheoptionofoutsourcingsomeofthesesystemstodifferentproviders.For
instance,inlogistics,3PLsorThirdPartyLogisticsProviders,serveasanorganizationthatcan
runthesoftwareaswellasperformallofthebusinessprocesses.Havinga3PLrunyourlogistics
eliminatestheneedforhardwareandsoftware.3PLscanpossiblyreplacepersonnelwithinthe
firm.Theuseof3PLsismostcommonwithsmallerfirms.
Themainreasonstooutsourcearetoreducecapitalexpenditureforsoftwareandhardware.It
mayalsoreducecostsasaresultofpartner’seconomiesofscale;theyoftenhavetheabilityto
doitfasterandbetteraswellasbemoreflexibileandagile.Itmayalsobeanopportunityto
increaselevelsofserviceatreasonablecosts.Firmcanfocusoncorebusinessandbringin
expertisethatisnotaffordablein-house.Therearemyriadotherreasonstooutsource,but
therearealsomanynotto,discussedbelow.
Atthetopofthereasonsnottooutsourcearesecurityandprivacyconcerns;someoneelsehas
accesstothefirm’sdata.Therearealsoworriesofvendordependencyandlock-in.Thefirm
maylosein-houseexpertisetoacorefunction.Therearealsohigh-migrationcostsaswellas
concernsoveravailability,performance,andreliability.Thereareadditionalreasonsnotto
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outsource.Firmsneedtoweightheprosandconsofoutsourcingmatchedwithbusiness
objectivestodecidewhichissuitableforthem.
Software Vendor Selection
Intheend,afirmmustselectitsvendor.Somefirmsthrowadartonthewall,andthatisits
choice.Othershaveanorganizedandformalizedfashiontoselectavendorandingeneralit
goesasfollows:
1. FormaProjectTeam(Internaland/orExternal)&Objectives
2. UnderstandtheBusinessandNeeds:reviewcurrentbusinessprocesses,prioritize
needs/functionality,createRequestforInformation(RFI)
3. CreateInitialShortListofPotentialSolutions&Vendors
4. In-depthReviewofShortListedVendors:havevendorsconductrealisticproduct
demonstrations,referencesfromcurrentusers.
5. CreateandDistributefinalRequestforProposal(RFP)
6. MaketheDecision:negotiatecontract,price,andservicelevelagreements(SLAs)and
establishanimplementationplanplan
Whilecostisoneoftheprimaryfactorsindecision-making,therearemanyothercriteriathat
needtobeevaluatedontopofcost.Theyare:
• Functionality–doesthesystemfeaturesfitthefirm’sprocessesandneeds?
• EaseofUse–howfastistheinitiallearningcurveandon-goinguse?
• Performance–whataretheprocessingspeeds?
• Scalability–howwellcanthesystemexpandandgrowwiththefirm?
• Interoperability–howwelldoesthesystemintegratewithothersystems?
• Extendibility–howeasilycanthesystembeextendedorcustomized?
• Stability–howreliableisthesystemintermsofbugsandup-time?
• Security–howwelldoesthesystemrestrictaccess,controlconfidentialdata,and
preventcyberhacking?
• Support–howisthequalityofthevendorintermsofimplementation,support,
training,thoughtleadershipetc.?
• VendorViability–howisthevendor’sfinancialstrengthandwillingnesstosupply
updatesandenhancements?Willtheybeherein3years??
Becausethereareavarietyofcriteriathatfirmswillbeevaluatingvendorson,ascorecardisa
popularwaytocapturefinancialandnon-financialattributes.Thecriteriacanbescoredasrank,
ratings,andgrades.Scorecardstendtobeverydetailedandcanevenbebrokendownby
specificfeatures.Theselectioncanbemadebetweenvendorsorbetweenalternativehosting
platforms.
Total Cost of Ownership
SoftwareLicense:Directcostofthesoftwaresystemitself–assumingownership.
Maintenance:Ongoingannualcoststoguaranteeupgradesandbugfixes.
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Platform/Hardware:Costofneededhardwaretorunthenewsoftware.
Training:Costoftraininginitialandongoingpersonnel
Implementation:Costofgettingthesystemtogolive!Thesevarywidelybetweensystemsand
firms.
Customization:Costofmodifyingthesystemitselftofitthefirm’sprocesses.NothinginSCMis
usedstraightoutofthebox(vanilla).
SystemIntegration
Costofinterfacingthissystemwithothermodulesandmodifyingexistingsystemstofit
Implementation
Whileselectingavendorcanbedifficultandtimeconsuming,theactualprocessof
implementationcantakeanevenmoresignificantamountoftimeandconsumealotof
resources.Thereareafewdifferentapproachestoimplementation.TheyincludeDirect(orBig
Bang),Parallel,Pilot,andPhased(orRolling).Eachofthesehasitsownpositivesandnegatives,
buttheapproachmustsuittheneedsofthebusiness.
Movingfromanoldmul7-modulesystemtoanewmul7-modulesystem.
Implementa7onApproaches
#Modules #Loca7ons Comments
Converted Converted
Direct
or
BigBang
All
All
•  Switchfromtheoldtonewsystemoccursononeday
•  Painofswitchconcentratedforen7refirm
•  Fastestimplementa7on7me,buthighestrisk
•  Post-implementa7onproduc7vitydrop
•  Highpoten7alforsystemwidefailuresduetoinsufficienttes7ng/training
Parallel
All/Some
All/Some
•  Oldandnewsystemskeptonfortes7ngperiod
•  Lowestriskoffailure,buthighestcostandlongestimplementa7on7me
•  Employeesdodoubleentrywork
Pilot
All
One
Phased
or
Rolling
One
All
•  Fullimplementa7onofallmodulesatoneloca7on
•  Iden7fybugsorissuesthatarecorrectedpriortolargerrollout
•  Containsanypoten7alfailurefrominfec7ngallloca7ons
•  Testsindividualmodulesandintegra7onsimultaneously
•  Implementa7onofonemoduleata7meacrossthenetwork
•  Longerimplementa7ondura7onthandirect,butwithlowerrisk
•  Usershavemore7me&learnastheygo-nodipinperformancea3er
•  Learnandfixasyougo–beserprocessforlaterimplementa7ons
•  Lossofmanagerialfocusover7meandacon7nuousstateofchange
•  Poten7alformissingdataduringtransi7onalimplementa7onperiod
•  Mightrequiretemporarybridgesfromoldtonewsystemsduringtransi7on
MIT Center for
Transportation & Logistics
27
Thereareafewbestpracticestokeepinmindwhengoingaboutimplementation.They
include:
1. Secureseniorexecutivecommitment:abilitytogatheranduseresources,empower
team.
2. Forminterdisciplinaryteam(s)
3. Createaclearandspecificscopedocument
4. Buildextensivetestingintotheprojectplan(youcan’ttesttoomuch)
5. Includeextensiveusertrainingintotheprojectplan
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Learning Objectives
•
•
•
•
•
•
Recognizeselectingasoftwarevendorisanintertwineddecisionbetweenarchitecture
andsource.
UnderstandtradeoffsbetweenOn-PremiseandCloudbasedsystems.
KnowthedifferencesbetweenIn-House,BestofBreed,ERPExtensions,andOutsourced
formsofsoftwaresystems.
Reviewtheselectionprocess,recognizingtherearemultipleattributes,andthetotal
costofownershipiscomplex.
Understandthechallengeofimplementationandthevariousapproachesto
implementingsystemswithinafirm.
Reviewbestpracticesofimplementation.
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MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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47
Technology Trends
Summary
Asfuture(orcurrent)supplychainprofessionals,youwillbeconstantlyfacedwithtechnology
trendsthatwillinfluenceyourworkandfutureplanning.Manyofthetoolswehavearmedyou
witharetriedandtruemethodsandmaynotchange.Others,suchasvarioussystemsand
technologieswillchangecontinuously.Itisimportanttobeawareofafewemerging
technologytrendsweseetoday(asof2016).Wewillintroduceyoutoafewoftheseinthe
nextlesson.Eachsectionwillcoverwhatthetrendis,itsstatus,andpotentialimpact.
Trend: Autonomous Vehicles
Autonomoustrucksaretrucksandothervehiclesthatcanoperatewithminimal(orno)human
interaction.TherearevariouslevelsofAutomationfromNone(0)allthewayuptoLimitedSelfDrivingAutomation(Level3).Thestatusasoftodayisthatautonomousdeliveryhasalready
happened.ThefirstpaidautonomousdeliveryoccurredinColoradoinOctoberof2016;Otto
deliveredafullTLofbeer.TherehavebeensignificantinvestmentsintechnologysuchasUber
acquiringOttoin2016for$680M.IntelacquiredMobileyein2017for$15B.Thedirectimpact
ishuge:asingledayrangeoftruckscoulddoubletoabout1000miles.Itcouldlowerfuelcosts
duetolowerspeeds.
Approach
§ Networkmodelingwithnewtransportcharacteristics
§ Truckingindustrystrategy(Porters5ForcesModel)
Trend: Delivery Drones
Youhavealmostdefinitelyheardofdeliverydronesasthefutureofdelivery.DeliveryDrones
areanunmannedaircraftthatcannavigateautonomously,withoutdirecthumancontroloris
guidedremotely.Itwasusedinmilitaryoperationsstartingin2000.DroneDeliverieshave
alreadyhappenedsuchasonDec.72016,AmazonPrimedeliveredanAmazonFireTVanda
bagofpopcornbydronetoamannearCambridge,UK.Flirteyand7-Elevendeliveredachicken
sandwich,donuts,candy,SlurpeesandhotcoffeeviadroneinJuly2016inRenoNV.
Directimpactsincludetheabilitytosendsmallloadstoremotelocationsquickly.Itexpands
deliverycapabilitiesusingopenairwithoutusingexistinginfrastructure.Itwillessentiallyserve
asanewtransportationmodeforveryfastreplenishmentofverysmallshipmentsizeovera
closedistance.
AnalysisApproach
§ Networkmodelingwithnewtransportcharacteristics
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§
Demandplanning–newserviceoffering
Trend: Mobile Computing
Thenextmajortechnologytrendismobilecomputing.Itisatechnologythatallows
transmissionofdata,voiceandvideoviaacomputeroranyotherwirelessenableddevice
withouthavingtobeconnectedtoafixedphysicallink.Todaymobilecomputinghasgrown18
foldoverthepastfiveyearsofuse.Thereare8billionmobiledevices(including325million
wearabledevices)currentlyinuse.Smartphoneusagegrewin38%in2016,buttheyareonly
usedasphones3%ofthetime.
Immediatedirectimpactsareobvious.Weuseitconstantly.Anyonewithasmartphoneisable
toaccessdataandsystemsfromanywhereatanytime.Forsupplychains,itmeansnew
paradigmsofshippingandretailsupplychainssuchasOmnichannel.
AnalysisApproach
§ Demandplanningmodels–impactoflocationandsignalsforbetterforecasting
§ Inventorymodeling–changingstockingpointsandfunctions
§ Transportationmodeling–deliveryformorediverselocations
§ Warehousing–changingthefunctionoffacilities
Additive Manufacturing
Thefinaltrendwewilltalkaboutinthislessonisadditivemanufacturing.Thereareofcourse
manyothersthatyouwillcrossinyourpathasasupplychainprofessional;thesearejustafew
toshowwhatiscomingdownthelinecurrently.Additivemanufacturingistheprocessof
makingaphysicalobjectfromathree-dimensionaldigitalmodel,typicallybylayingdownmany
thinlayersofamaterialinsuccession.Asof2016additivemanufacturinggrew26%to$5.16B.
Therearemanydifferentprocessesthatincludebutarenotlimitedto:materialextrusion,
materialjetting,binderjetting,sheetlamination.Materialsincludepolymers,composites,
metals,ceramics,paper,andmore.Ithasexpandedbeyondhobbyandprototypinguses.A
primaryexampleisGEacquiringSwedenbasedArcamandGermanybasedSLMsolutionsfor
$1.4Bin2016.
Learning Objectives
•
•
•
•
Technologyisalwayschanging!
Assupplychainprofessionalsyouwillbecontinuouslyfacedwithnewtechnologytrends
anddecidingwhatisviable.
Beintroducedtocriticalthinkingabouttechnologytrends,theirpotentialdirectand
indirectimpacts,andtimelines.
Reviewcurrenttechnologytrends.
V1 Spring 2017・CTL.SC4x – Technology and Systems・MITx MicroMasters in Supply Chain Management
MIT Center for Transportation & Logistics・Cambridge, MA 02142 USA ・[email protected]
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49