Combining Experimentation and Theory: A Hommage to Abe Mamdani

423 Pages·2012·9.79 MB·English

by  Ebrahim H. Mamdani

EnricTrillas,PieroP.Bonissone,LuisMagdalena,andJanuszKacprzyk(Eds.)
CombiningExperimentationandTheory
Studiesin Fuzziness andSoft Computing,Volume271
Editor-in-Chief
Prof.JanuszKacprzyk
SystemsResearchInstitute
PolishAcademyofSciences
ul.Newelska6
01-447Warsaw
Poland
E-mail:[email protected]
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ISBN978-3-642-16894-9 ISBN978-3-642-24665-4
Enric Trillas, Piero P. Bonissone,
Luis Magdalena, and Janusz Kacprzyk (Eds.)
Combining Experimentation
and Theory
A Homage to Abe Mamdani
ABC
Editors
Prof.EnricTrillas Prof.LuisMagdalena
EuropeanCentreforSoftComputing EuropeanCentreforSoftComputing
EdificiodeInvestigación EdificiodeInvestigación
CalleGonzaloGutiérrezQuirósS/N CalleGonzaloGutiérrezQuirósS/N
33600Mieres,Asturias 33600Mieres,Asturias
Spain Spain
Email:[email protected] Email:[email protected]
Dr.PieroP.Bonissone Prof.JanuszKacprzyk
ChiefScientist SystemsResearchInstitute
CoolidgeFellow PolishAcademyofSciences
GEGlobalResearch Ul.Newelska6
SoftwareSciencesandAnalytics 01-447Warsaw
OneResearchCircleK1-4A10A Poland
Niskayuna,NY12309 Email:[email protected]
USA
Email:[email protected]
ISBN978-3-642-24665-4 e-ISBN978-3-642-24666-1
DOI10.1007/978-3-642-24666-1
StudiesinFuzzinessandSoftComputing ISSN1434-9922
LibraryofCongressControlNumber:2011939331
(cid:2)c 2012Springer-VerlagBerlinHeidelberg
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ProfessorEbrahimH. “Abe”Mamdani(1942 –2010)
Introductory Words
AnunexpectedpassingawayofProfessorEbrahimA.Mamdaniwasabigshockfor
allhisfriendsandcolleagues,nottomentionhiscloserelatives.Nobodyexpected
suchasuddenendfromanapparentlysimplesurgicalinterventioninaleg.Asudden
endthatremovedanypossibilityofofferingAbeMamdania well-deservedpublic
tribute, in which he surely would have addressed the audience with his views on
scientificandtechnologicalresearch.Thefuzzycommunityaroundtheworldisin-
debtedtoAbeMamdani,whointroducedFuzzyControlasanengineeringmethod.
Since January2010,severalobituarieson his memoryhave been carriedoutin
congresses, web pages of scientific societies, and journals; many others will fol-
low.Nevertheless,the editorsofthisbookfeltthenecessity ofofferinga different
kindofposthumoushomage,betterfittingAbe’spersonalwayofdoingthings.The
maingoalwastocollectandpresentasetofideasthat,afterreflection,couldcre-
atesomeenlighteningcontroversy,lookingforwardsinsteadofbackwards.Forthis
reason,theeditorsdecidedtopublishabookinwhichresearchersacquaintedwith
Mamdani,personallyorthroughhiswork,wouldpresentoriginalpapersespecially
written for the occasion and, in some way, related to his work. The homage this
booktriestorepresentanditsunderlyinggoalwillbefulfilledifsomeofthepapers
initwillpromptafertilescientificdebateontheissuescoveredinthebook.
Mamdani’sownlife andvitalexperience,notforgettinga successfulbutforced
changeinhisfieldofresearchaftertheUKGovernmentregrettablysuppressedthe
funding to Fuzzy Control, are not only very illustrative of his never surrendering
attitude,buta goodexampleforeverybody.His subtlesense ofhumor,hisjoyfor
life, and his will to critically help people, were remarkable characteristics deeply
appreciatedforallthosethatbenefitedfromhisfriendship.
ThefoureditorsaredeeplygratefultoMrs.VirginiaAnneMamdani,forherkind
permissionto publishthecorrespondencebetweenProfessorMamdaniandoneof
them. This private correspondencestarted after a talk delivered by Mamdani to a
groupofMaster’sstudentsattheEuropeanCentreforSoftComputing,andfinished
fewweeksbeforeheenteredinthehospital.Unfortunately,suchconversationswill
remainunfinishedforeverbut,althoughpartially,theyreflectprettywellMamdani’s
thought.
VIII IntroductoryWords
ThefoureditorsalsoacknowledgethecontributionofProfessorLotfiA.Zadeh
to the book with the lovely ‘Foreword’that follows, and thank all the authors for
theireffortsincontributingtothebook.
EnricTrillas
PieroP.Bonissone
LuisMagdalena
JanuszKacprzyk
Foreword
Abe Mamdani was a highly visible figure in the academic world of science and
technology.Hisprematurepassingawaywasadeeplossforallwhoknewhimand
admiredhisdirectness, intellectandarticulate personality.CombiningExperimen-
tationandTheory/anHomagetoAbeMamdaniisacollectionofpapersco-edited
byEnricTrillas,PieroBonissone,LuisMagdalenaandJanuszKacprzyk,andpub-
lished by Springer.In additionto beingan homageto Mamdani,the volumeis an
importantcontributiontotheliteratureoffuzzylogicanditsapplications,especially
in the realm of fuzzy control—a realm whose genesis owes so much to Mamdani
andhisstudents.
Theageoffuzzycontrolbeganin1975withthepublicationoftheseminalpaper
by Mamdani and Assilian “An Experiment in Linguistic Synthesis with a Fuzzy
LogicController”InternationalJournalofMan-MachineStudies7(1):1-13(1975).
Thepapersinthisvolumeareaneloquenttestimonytotheenormousimpactofthe
ideaspresentedin thatpaper.Today,the conceptualframeworkoffuzzycontrolis
employedinaverywiderangeofapplicationsextendingfromhouseholdappliances
anddigitalcamerastobiomedicalinstrumentationandfrauddetectionsystems.
Thedebutoffuzzycontrolwasnotmetwithapprobationbythecontrolsystems
community.Aleadingfigureincontroltheory,ProfessorRobertBitmead,wrotein
a1993lettertotheeditoroftheIEEEControlSystemsMagazine:
My conclusion from these experiences is that the CSS and AACC have been
remiss in their attention to scholarly detail in the scrutiny of the sessions and
papers admitted to our own conferences. A quick scan of the recent Transac-
tionsIndex1981-1991showsthatfuzzycontrolappearsveryinfrequentlyinour
archivaljournalbutinfeststheCDCandACCtremendously.Beforewecriticize
othersfortheiracquiescenceinfuzzytravesties,wehadbetterlooktosettingour
ownhouseinorder.Instraighteningoutourownaffairs,however,weshouldbe
carefulnottodisaffectthosereputablepeopleworkingonFLC,neuralnetwork
control, expert systems, and so on. In marked contrast to CSS, the European
CommunityControlAssociation,initsveryfirstnewsletterofJune1992,com-
pletelydismissesanyassociationwithFLC.Theypublishedthreeveryscathing
X Foreword
articlesbySaundersMacLane,ErwinSchrdinger(whichisabitsilly)andPierre
Bernhard.
InfairnesstoProfessorBitmead,inalettertomedatedFebruary1,2010hewrites
“While I am polemic in the letter and I was initially skeptical about Fuzzy Logic
Control, you will see fromthe letter that I am really an advocate for the area and
foritsapplicationsandtheory.”Itisasoberingfactthatreflectingtheskepticismof
thecontrolsystemsestablishment,thegovernmentagencyinUKwhichsupported
Mamdani’sworkdecidedtoterminateitssupportatatimewhenfuzzycontrolwas
initsearlystagesofdevelopment.
What explains the critical and sometimes hostile reaction of some of the lead-
ingmembersofthecontroltheoryestablishmenttotheideaswhichunderliefuzzy
control?Abitofhistoryisinorder.
When I wrote my first paper on fuzzy sets in 1965, my expectation was that
theprincipalapplicationsoffuzzysettheorywouldbeintherealmofbranchesof
science in which human judgment,perceptionsand emotionsplay a primaryrole.
However,beinga system theorist, it did nottake me long to realize that fuzzy set
theory had the potential for important applications in the realms of hard sciences
and engineering.In 1971,I wrote a paper entitled “Toward a theoryof fuzzy sys-
tems,”andin1972apaperentitled“ARationaleforFuzzyControl.”Ina1973paper
entitled“Outlineofanewapproachtotheanalysisofcomplexsystemsanddecision
processes,”twobasicconcepts,theconceptofalinguisticvariableandtheconcept
ofafuzzyif-thenrulewereintroduced.Thesetwoconceptsservedasspringboards
forfuzzycontrol.
Theinitialreactiontotheconceptofalinguisticvariablewasevenmoreskeptical
andhostilethanthereactiontofuzzycontrol.ThisiswhatRudiKalman,abrilliant
systems scientist and a student in my courses at Columbia University, had to say
afterlisteningtomyfirstplenarylectureontheconceptofalinguisticvariableata
conferenceinFrancein1972:
I would like to comment briefly on Professor Zadeh’s presentation. His pro-
posals could be severely, ferociously, even brutally criticized from a technical
pointofview.Thiswouldbeoutofplacehere.Butabluntquestionremains:Is
ProfessorZadehpresentingimportantideasorisheindulginginwishfulthink-
ing?NodoubtProfessorZadeh’senthusiasmforfuzzinesshasbeenreinforcedby
theprevailingclimateintheU.S.—oneofunprecedentedpermissiveness.‘Fuzzi-
fication’isakindofscientificpermissiveness;ittendstoresultinsociallyappeal-
ingslogansunaccompaniedbythedisciplineofhardscientificworkandpatient
observation.
Toadegree,thehostilereactiontofuzzycontrolandothertheoriestowhichfuzzy
is attached is rooted in the fact that fuzzy is a word with pejorative connotation.
But a more substantivereasonis thatthere is a deep-seatedtraditionin science of
accordingmuchmorerespecttonumbersthantowords,largelybecausewordsare
lessprecisethannumbers.Thequestionis:Ifwordsarelessprecisethannumbers,
whyusewords?Theanswerissimplebutnotquiteobvious:precisioncarriesacost.
Foreword XI
Akeyideawhichunderliesfuzzycontrolisthefollowing.Ifthereisatolerancefor
imprecision—whichisfrequentlythecaseintherealworld—thentheuseofwords
makesitpossibletoexploitthistolerance,leadingtoreducedcostandgreatersim-
plicity.Inaddition,theuseofwordsopensthedoortoreplicationoftheremarkable
human capability to make intelligent decisions in an environment of uncertainty
and imprecision, without any measurements and any computations. It is this key
ideathatthecriticsoffuzzycontrolhavefailedtorecognize.
A case in pointis Professor Yamakawa’sstabilization of an invertedpendulum
throughtheuseoffuzzycontrol.Aninvertedpendulummaybestabilizedthrough
applicationofclassicalcontroltheory,startingwithformulatingthenonlineardiffer-
entialequationswhichdescribetheinvertedpendulum.WhatProfessorYamakawa
showedin1989isthataninvertedpendulummaybestabilizedthroughtheuse of
abouttenfuzzyif-thenrules—ruleswhichaten-year-oldchildcanformulatewith-
outanyneedforfamiliaritywithcontroltheory.Additionally,ProfessorYamakawa
showedthatthesamerulesarecapableofstabilizinganinvertedpendulumtowhich
acageisattachedatthetopwithamouserunninginsidethecage.Writingdifferen-
tialequationsofmotionforaninvertedpendulumwithamouseontopisbeyondthe
reachofclassicalcontrol.A remarkabledemonstrationofthepoweroffuzzycon-
trolwasmadeinChinabyChinesecontrolengineersLiHongxing,MiaoZhihong
andWangJia-Yin.Theystabilizedafour-stageinvertedpendulumthroughtheuse
offuzzycontrol.
Another case in point is the problem of automation of driving a car. Humans
candriveacarinCalcutta—acitywithchaotictrafficinwhichtherearefewtraffic
lightsandfewtrafficcontrols.Ifaclassicalcontroltheoristwereaskedtoautomate
drivinginCalcutta,thenhe/shewouldfindclassicalcontrol-andespeciallyoptimal
control—tobe of little orno use. The problemmaynotbe solvedin ourlifetimes
butifandwhenitis,itwillnecessarilyemployfuzzycontrol.
The seminal work of Mamdani and Assilian was a major achievement—an
achievementwhichopenedthedoortowide-rangingapplicationsoffuzzycontrol.
Whatiscertainisthatincomingyearsfuzzycontrolwillbegaininginrecognition
andacceptance.AbeMamdanipassed awaybutthelegacyofhispioneeringwork
withSedrakAssilianwillcontinuetogrowinvisibilityandimportance.
Berkeley,California LotfiA.Zadeh