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Better medical efficiency by means of hospital bed management optimization - a comparison of artificial intelligence techniques

Abstract

The combination of the phenomenon of overcrowding with inefficient management of resources is a major obstacle to the good performance of hospital units and consequently the degradation of the medical service provided. This paper provides an analysis to understand the correlation between poor bed allocation and hospital performance. The lack of an efficient resource planning among the various medical specialties can negatively impact the quality of service. Four different techniques were compared to realize which is better suited for optimizing the allocation of beds in Hospital units. Hill Climbing and the Genetic Algorithm stood out the others, the latter presenting greater consistency and a shorter computation time. When tested with real data from Centro Hospitalar do Tâmega e Sousa, attained a total of 0 wrongly allocated patients against 92 when compared with former methods. This translates into better patient service, reduced waiting time and staff workload, which means increased performance in all adjacent medical issues.

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Better medical efficiency by means of hospital bed management optimization - a comparison of artificial intelligence techniques

Author: Lobo, Afonso Augusto Paula; Barbosa, Agostinho; Guimarães, Tiago André Saraiva; Lopes, João; Peixoto, Hugo; Santos, Manuel
Publisher: Springer Nature
Year: 2023
DOI: 10.1007/978-3-031-49011-8_21
Source: https://repositorium.uminho.pt/bitstreams/8fc3a7b3-c417-4e7b-b348-e7b04a9aa64f/download
1
Be e Medical E iciency by means o Hospi al Bed
Managemen Op imiza ion – a Compa ison o A i icial
In elligence Techniques
A onso Lobo1, Agos inho Ba bosa2, Tiago Guima ães1, João Lopes1, Hugo Peixo o1,
Manuel Filipe San os1
1 Cen o ALGORITMI, Uni e si y o Minho, 4800-058 Guima ães, Po ugal
2 Cen o Hospi ala do Tâmega e Sousa, 4564-007, Pena iel, Po ugal
[email protected] , [email p o ec ed]
saude.p , [email p o ec ed],
[email p o ec ed], [email p o ec ed],
[email p o ec ed]
Abs ac . The combina ion o he phenomenon o o e c owding wi h ine icien
managemen o esou ces is a majo obs acle o he good pe o mance o hospi al
uni s and consequen ly he deg ada ion o he medical se ice p o ided. This
pape p o ides an analysis o unde s and he co ela ion be ween poo bed
alloca ion and hospi al pe o mance. The lack o an e icien esou ce planning
among he a ious medical special ies can nega i ely impac he quali y o
se ice. Fou di e en echniques we e compa ed o ealize which is be e sui ed
o op imizing he alloca ion o beds in Hospi al uni s. Hill Climbing and he
Gene ic Algo i hm s ood ou he o he s, he la e p esen ing g ea e consis ency
and a sho e compu a ion ime.
When es ed wi h eal da a om Cen o Hospi ala do Tâmega e Sousa, a ained
a o al o 0 w ongly alloca ed pa ien s agains 92 when compa ed wi h o me
me hods. This ansla es in o be e pa ien se ice, educed wai ing ime and s a
wo kload, which means inc eased pe o mance in all adjacen medical issues.
Keywo ds: A i icial In elligence, Mode n Op imiza ion, Hospi al Bed
Managemen , Medical E iciency.
1 INTRODUCTION
Nowadays, mo e and mo e da a ega ding hospi als and all he su ounding a ea in he heal h
sec o a e becoming a ailable o us. This means an inc easingly acili a ed use o a i icial
in elligence echniques o seek a signi ican imp o emen in he e iciency o hese se ices, om
componen op imiza ion o e icien managemen o esou ces in he hospi al uni s, con ibu ing
in a signi ican way o mone a y cos educ ion[1]
The app oach pe o med in his ype o p oblem is called p esc ip i e analysis. I is an
analysis wi h he pu pose o esponding o eal decisions ega ding he planning o esou ces in
he hospi al uni s as well as he alloca ion o ce ain medica ions depending on he con ex , always
aiming o each he bes possible solu ion [2]. This s udy is cen e ed on he de elopmen and
compa ison o Machine Lea ning Op imiza ion Algo i hms (MLOA), o in elligen and e icien
managemen o beds in he di e en special ies o a hospi al, co esponding in he bes possible
way o he needs o he hospi al as a whole.
The applica ion o hese algo i hms is becoming mo e and mo e ele an as we a e
wi nessing a global aging o he popula ion which causes he low o pa ien s o be g ea e and
he p essu e on heal h se ices o inc ease. The esul o his p essu e, wi hou p ope planning, is
an ine icien managemen and o ganiza ion o hospi al uni s, alling sho o hei needs and an
inc ease in ope a ing cos s [3].
Adop ing op imiza ion algo i hms o answe hese ques ions and ob ain he bes possible
planning has been one o he bes answe s o his ype o p oblem, ep esen ing an inc ease in
2
pe o mance in se ice deli e y and ope a ion o hospi al uni s [4].
In he ealiza ion o his p ojec as ollowed he app oaches o Design Science Resea ch.
2 BACKGROUND
2.1 Resou ces Planning in Hospi al Se ings
A good planning o esou ces in heal h ca e uni s o gua an ee an adequa e esponse and
pe o mance o hei needs is becoming inc easingly di icul and he e o e i becomes mo e
pe inen o ind ways o ob ain a be e use and op imiza ion o esou ces h ough success ul
planning and managemen .
The main obs acle o a good o ganiza ion and managemen o esou ces in a hospi al is
due o he cu en phenomenon o o e c owding coupled wi h an ine icien managemen o
esou ces, inc easingly accen ua ing he unde u iliza ion o hem, i.e. he low o pa ien s is oo
high o he esponse ha hospi als can gi e, educing he esponse capaci y and consequen
o e c owding [5].
Acco ding o a s udy conduc ed a he Uni e si y o Cali o nia, he main easons o his
O e c owding a e concen a ed in he high olume o pa ien s, he complexi y o ela ed medical
issues, delays in he p o ision o se ices and mainly in he poo managemen and alloca ion o
beds in hospi als being his ac o conside ed as he one ha ep esen s mo e weigh o he
p oblem in ques ion [6].
The inadequa e alloca ion o beds is due, besides he lack o a ailable beds, o an
ine icien managemen o esou ces which causes a nega i e di e en ial be ween he needs
p esen ed and he esponse capaci y. This means ha e en in scena ios whe e he esou ces can
mee he needs, occu s a subop imal use o hem esul ing in loss o pe o mance, causing delays
and cancella ion o admissions and su ge ies, ea ly ans e s o pa ien s and accumula ion o
cos s[7].
To his end, i is impo an o ind a o m o model o o ganiza ion based on wo main
a iables: he occupancy o beds and he o ecas ing o pa ien low, in o de o ob ain an e icien
managemen o esou ces ha allows he p ope unc ioning o hospi al ins i u ions being able o
p o ide adequa e ca e o hei pa ien s o ensu e a esponse capaci y app op ia e o he needs [5,
6].
2.2 Rela ed Wo k
The planning and managemen o esou ces in hospi al uni s ep esen a need and a pe inen
conce n in ou days. We a e he e o e wi nessing a sys ema ic a emp o ind he bes possible
solu ion ha allows us o espond e ec i ely o he p oblem o o e c owding using mo e e icien
managemen o means. The e a e se e al s udies p oposing solu ions and showing impo an
cha ac e is ics o be conside ed o achie e he desi ed success.
One way o p omo e e icien esou ce managemen in hospi als is he use o he Ma ko
model. The Ma ko model, o s a egy, is a ma hema ical queuing model in ending o p edic and
imp o e he wai ing ime o pa ien s o se ice. This app oach was he a ge o a s udy published
in Heal hca e Enginee ing, whe e he ocus was op imizing a model in o de o ob ain g ea e
e iciency in bed alloca ion. This model was based on se e al indica o s such as he a e age
numbe o pa ien s, bed u iliza ion a e, pa ien s op a e, and pa ien a e age wai ing ime.
Simula ions and se e al expe imen s conduc ed wi h his model showed a signi ican
imp o emen in esou ce alloca ion and o e all pa ien sa is ac ion [8].
I was made in 2022 a s udy wi h he in en o p edic ing pa ien Leng h O S ay (LOS)
h ough machine lea ning models and inpu da a ega ding medical eco ds and demog aphic
in o ma ion o pa ien s in he in e nal medicine special y o a hospi al in Po ugal. The au ho s
ollowed wo scena ios: one ha p edic s he LOS a he ime o admission; and ano he ha
upda es he p edic ion du ing he hospi aliza ion p ocess. They compa ed ou machine lea ning
algo i hms: decision ee, andom o es , k-nea es neighbo s and g adien boos ing. They ound
ha g adien boos ing pe o ms he bes , achie ing an accu acy o abou 96%. They also ound
ha including da a abou he pa ien 's heal h elec onic eco d, such as exams, lab esul s,
3
medica ions and su ge ies, imp o es he p edic i e capaci y o he model. They concluded ha
hei model can help heal h p o essionals plan and manage hospi al esou ces mo e e icien ly and
imp o e he quali y o ca e o pa ien s [9]
In 2020, In B azil in Minas Ge ais he use o op imiza ion algo i hms, mo e speci ically
a gene ic algo i hm, was also he a ge o s udy o imp o e he alloca ion o beds in hospi als in
he egion, p o ing, despi e an inc ease o 13% in ope a ing cos s, a educ ion up o 1/30 o he
e usal pa ien a e [10].
Following he applica ion o MLOA, mo e speci ically he gene ic algo i hm, a s udy was
conduc ed a Tous Hospi al in Teh a based on pa ien low da a, a s udy aimed a op imizing he
use o human esou ces in he hospi al in ques ion. The objec i e was o ind a solu ion ha
ep esen ed he minimum op imal numbe o s a equi ed o mee he needs o he hospi al, hus
leading o a educ ion in was e, ope a ing cos s and an inc ease in he e iciency and e ec i eness
o he se ice p o ided, h ough a be e dis ibu ion o s a hou s. In he applica ion o his
algo i hm, he i ness unc ion, a cons i uen unc ion o he algo i hm, whose pu pose is o
a ibu e a ce ain sco e o a ce ain solu ion o he p oblem, ook in o conside a ion pa ame e s
such as he employee's sala y, he numbe o pa ien s seen on a e age pe employee and he
a ailable wo k shi s. I was hen, a e 500 gene a ions, ound a solu ion o s a hou ly
alloca ion in which only 69 employees we e needed compa ed o he 108 ac i es in unc ion daily
in he hospi al, o gi e he same o be e esponse o he needs p esen ed [11].
When i comes o compa ing op imiza ion algo i hms wi h each o he , a s udy was
conduc ed a he Fukuoka Ins i u e in Japan, o e alua e he pe o mance o algo i hms such as
Hill Climbing, Simula ed Annealing and Gene ic Algo i hm o op imal alloca ion o ou e s in
o de o p omo e be e co e age and connec ion condi ions o Local A ea Ne wo ks. F om his
s udy esul ed an ad an age o Hill Climbing and Simula ed Annealing, showing o each he
desi ed esul s as e [12].
Following he pe o mance compa ison be ween he algo i hms, a s udy was conduc ed
in o de o unde s and he beha io o he Hill Climbing and Gene ic algo i hms o digi al
p edis o ion model sizing. F om his s udy i was concluded ha he gene ic algo i hm is
dependen on he inpu pa ame e s, and ha he la ge he popula ion size, he be e he esul s,
which also means a p opo ional inc ease in execu ion ime. The Hill Climbing algo i hm, on he
o he hand, does no depend on he inpu pa ame e s and can p esen i sel wi h a sho e execu ion
ime due o he inc ease in he popula ion size o he gene ic algo i hm. As o he pe o mance
compa ison ega ding he quali y o he solu ion ob ained, he gene ic algo i hm eached he
op imal solu ion mo e o en, while he hill climbing also p esen ed local op imal solu ions, i.e.,
solu ions close o he bes possible solu ion, bu no being so [13].
In he big pic u e we can obse e se e al di e en ways o y o achie e a mo e e icien
managemen o esou ces in hospi als. In mos o he s udies ega ding he alloca ion o beds and
esou ces in hospi al uni s, ac o s such as he Leng h O S ay (LOS) and he Occupa ion Ra e a e
highligh ed. The applica ion o MLOA o sol e his ype o p oblems has been s udied and i s
beha io is also obse ed, no only in alloca ion p oblems ela ed o he Hospi al indus y bu also
in he applica ion o se e al ypes o con ex s.
In his s udy he ocus will be on he applica ion o ou di e en machine lea ning
op imiza ion algo i hms wi h he objec i e o ob aining an op imal solu ion o he dis ibu ion o
beds by he di e en special ies o he hospi al, a oiding o e c owding. They will hen be
compa ed and concluded which one p esen s he g ea es impac and signi ican imp o emen in
he ma e o medical issues.
3 MATERIALS AND METHODS
3.1 Me hodologies
The documen was de eloped acco ding o he Design Science Resea ch me hodology, a
me hodology wi h he objec i e o c ea ing a amewo k o help sol e and in es iga e p oblems.
In his amewo k a i ac s ha gene a e new knowledge a e gene a ed and analyzed. This
me hodology is composed o six dis inc phases: P oblem Iden i ica ion and Mo i a ion(1),
De ining he Objec i es o he solu ion(2), Design and De elopmen (3), Demons a ion(4),
E alua ion(5) and Communica ion(6) [14].
4
3.2 Tools and Algo i hms
The de elopmen o his p ojec was all based on he Py hon language and i s espec i e lib a ies
(NumPy, Pandas, Ma plo lib, Ma h, Da eTime). The de elopmen pla o m was Google's Colab.
The algo i hms used a e Machine Lea ning Op imiza ion Algo i hms, highligh ing, Random
Sea ch, Hill Climbing, Simula ed Annealing, and Gene ic/E olu iona y Algo i hm.
3.3 Da a Se s
The da ase s used a e ela ed o pa ien low a he Cen o Hospi ala do Tâmega e Sousa (CHTS)
and i s espec i e special ies, o a pe iod co esponding o 4 yea s. This da ase con ained
in o ma ion such as, admissions, discha ges, espec i e days and imes, numbe o special y beds,
which pa ien s we e alloca ed o each special y and which pa ien s we e he esponsible o each
special y, and also con ained in o ma ion abou which days he pa ien was hospi alized in se ice,
in a pa icula special y
4 Expe imen s
The ollowing sec ion desc ibes he expe imen s in all hei phases.
4.1 P oblem Fo mula ion
The aim is o imp o e he misalloca ion o pa ien s in di e en special ies due o poo
managemen and planning o esou ces, speci ically beds. The ine iciency on managemen leads
o an unde u iliza ion o esou ces and a consequen inc ease in o e c owding. The p oposed
challenge was o ob ain an op imal solu ion o planning and dis ibu ing beds in he di e en
special ies o he hospi al, conside ing:
Max_bed - The o al numbe o beds in a hospi al;
Special ies – All he 36 special ies in he Hospi al;
Beds_needed – Numbe o beds needed on a ce ain day o each special y;
Bed_a ailable – Numbe o beds a ailable/emp y in each special y;
I is impo an o men ion ha he model solu ion o his p oblem would always ha e o comply
wi h wo es ic ions:
i) The sum o beds o be alloca ed in each special y on a gi en day, by he applied
algo i hm, should ne e exceed he maximum limi o a ailable beds o be used;
ii) The maximum numbe o beds o be alloca ed o a gi en special y should ne e
exceed he numbe o needs p esen ed, hus a oiding he unde use o esou ces.
4.2 Da a P o ided
The da ase p o ided o he s udy co esponded o he low o pa ien s in he CHTS o e a pe iod
o 4 yea s (2019-2022) and i had he ini ial dimension o 708492 ows x 15 columns. Table 1
shows he a ious sou ces p o ided and a b ie desc ip ion o hem.
Table 1. Da a Sou ces
Da a Sou ces
Desc ip ion
Admissions Inpa ien s
Da a ega ding he admission o pa ien s o he Hospi al,
hei special ies, da es, and imes.
5
Discha ges Inpa i en s
Da a iden ical o hose o pa ien ’s admission o he hospi al,
bu e e ing o he discha ges.
Pa i en s Alloca ion
Da a ega ding he special y whe e a ce ain pa ien was
alloca ed.
Special ies
A da a se ha con ained all he in o ma ion ega ding he
hospi al's special ies.
Beds
Real da a ega ding he numbe o beds exis ing in he
hospi al, in each special y, and abou he ype o bed in
ques ion.
I was possible o ob ain daily in o ma ion abou admissions, discha ges, pa ien ans e s and he
days on which hey we e unde admission o each special y. I was also possible o de e mine
ha he maximum numbe o beds a ailable in he hospi al was 551 beds.
4.3 Da a P epa a ion
In he da a p epa a ion phase o la e use in he op imiza ion models, all da a wi h cons uc ion
e o s o Null o NaN alues we e i s iden i ied. Nex , ele an da a o he analysis o bed
alloca ion, epea ed o edundan a ibu es we e iden i ied. To a be e impac unde s anding and
p oblem sol ing, an impo an ans o ma ion was pe o med dis inguishing wo classes o
inpa ien s:
• physical pa ien s - pa ien s physically admi ed o he se ice esponsible o hei
ea men ;
• esponsible pa ien s - pa ien s who a e physically hospi alized in se ices o he
han hose ha ea hem.
These wo classes co espond o co ec and inco ec bed dis ibu ion, espec i ely. A co ec bed
alloca ion ma ching he daily needs o each special y would maximize physical pa ien s and
minimize esponsible ones.
A e hese changes he da ase was ans o med in o a ime se ies, mo ing he da e
a ibu e o index and di ided in o 36 di e en sub-da ase s each co esponding o a speci ic
special y.
Is hen possible, o a gi en day, o know he low o pa ien s, wha he s a us o he
occupa ion o beds is and how many supplemen a y beds a e necessa y o supply he eal needs
o he special y.
4.4 Domain and Fi ness Func ion
Be o e applying MLOA algo i hms, i is necessa y o de ine: i) he solu ion space o he
p oblem; ii) how solu ions will be ep esen ed; iii) how o de ine he cons ain s; and i ) how o
e alua e he e iciency o he p esen ed solu ions. I is he e o e impe a i e o de ine he p oblem
domain and he objec i e unc ion.
The p oblem domain de ines how he solu ion se will be ep esen ed gi en he p oblem
cons ain s. The domain co esponds o he minimum and maximum numbe o beds a ailable in
each special y so ha he solu ion is always possible in he space o he p oblem since i doesn'
exceed he maximum numbe o beds needed o he day.
In o de o op imize he algo i hms' pe o mance and dec ease he p obabili y o
unde u iliza ion o esou ces, a "dynamic domain" was c ea ed depending on he day in ques ion.
Con a y o wha is usually unde s ood as a ixed a iable in he p oblem, in his p oblem he
domain may a y acco ding o he daily needs o he di e en special ies o he hospi al. In o he
wo ds, o each day, he domain could a y be ween 0 and he numbe o pa ien s unde he
esponsibili y o each special y.
The solu ion was ep esen ed in an a ay o 1 dimension, wi h 36 elemen s, each

6
co esponding o an in ege numbe o beds o alloca e in a gi en special y o he day in ques ion.
The i ness unc ion o objec i e unc ion has as i s main objec i e o e alua e a se o
solu ions. This unc ion assigns a ce ain sco e o he solu ion o be e alua ed aking in o a accoun
a se o condi ions speci ic o he con ex o he p oblem. The goal is o minimize o maximize he
sco e. P esen ed in Pseudocode 1, he i ness unc ion ies o maximize he numbe o co ec
bed assignmen s knowing he daily Speciali y while minimizing he numbe o emp y on unused
beds. This leads o maximizing he numbe o pa ien s co ec ly assigned o a bed, i.e. maximizing
physical pa ien s o a he han esponsible pa ien s.
1. Fi ness Func ion Pseudo Code
sa is ac ion = 0
solu ion = solu ion inpu
max_bed = 551
I sum(solu ion) > max beds hen
sa is ac ion = -100
Fo each special y in solu ion do
I beds_needed == beds in solu ion and beds a ailable == 0
hen
sa is ac ion += 2
Else i beds_needed == beds in solu ion and beds a ailable >
0 hen
sa is ac ion += 1
Else i beds_needed no equal o beds in solu ion:
sa is ac ion -= |beds_in_solu ion – beds_needed| *
0.1
End I
End Fo
Re u n sa is ac ion
4.5 Op imiza ion Techniques
Fo op imizing he alloca ion o beds o pa ien s, ou di e en Op imiza ion Algo i hms we e
compa ed in o de o unde s and which one would ep esen a be e pe o mance. The
con igu a ion o he algo i hms was adap ed o ake he da e in one o he pa ame e s, since i is
an inpu a iable in he i ness unc ion and essen ial o de ine he daily domain o he p oblem.
The algo i hms ha we e conside ed in his s udy a e p esen ed below.
• Random Sea ch (RS)
A me hod based on he andom sea ch o solu ions du ing a ce ain numbe o ounds.
No e ha he g ea e he numbe o ounds he mo e likely i is ha a be e solu ion will eme ge,
inc easing in he same way he compu a ion ime [15].
2. RS Pseudo Code
ound = 0
bes _sa is ac ion = 0
bes solu ion TO NULL
7
While ound < ounds
solu ion = andom solu ion be ween he domain alues
sa is ac ion = i ness unc ion(da e, solu ion)
I sa is ac ion > bes _sa is ac ion hen
bes _sa is ac ion = sa is ac ion
bes solu ion = solu ion
End I
ound ++
End While
Re u n bes solu ion
• Hill Climbing (HC)
Hill Climbing is a local sea ch algo i hm, based on inc emen s and dec emen s o he
gene a ed solu ions, called "neighbo s", s a ing wi h an ini ial andom o p e iously p o ided
solu ion wi hin he domain. In i s execu ion, each gene a ed neighbo is analyzed and e alua ed
h ough he i ness unc ion as o i s quali y, and i one o he neighbo s gene a ed in he i e a ion
p esen s a be e esul , i becomes he cu en solu ion. The algo i hm con inues un il he e is no
possibili y o imp o emen in he solu ions. This algo i hm ends o ind local op imal solu ions.
3. HC Pseudo Code
Gene a e an ini ial solu ion s0,
s = s0
sa is ac ion = i ness(da e, s)
While e mina ion c i e ia no me do
neighbo _solu ion = Gene a e_Neighbo (s, domain)
neighbo _sa is ac ion = i ness(da e,
neighbo _solu ion)
I neighbo _sa is ac ion > sa is ac ion hen
s = neighbo _solu ion
sa is ac ion = neighbo _sa is ac ion
End I
End While
Re u n s
• Simula ed Annealing (SA)
Simula ed Annealing is a he modynamic analogous me hod inspi ed by he me al cooling
p ocess. This algo i hm consis s in a sequence o i e a ions whe e a p og essi e dec ease o
empe a u e occu s, ini ializing i in a high alue whe e each change is accep ed, being his
accep ance p obabili y smalle and smalle as he empe a u e dec eases acco ding o a cooling
a e. The sea ch me hod is iden ical o he HC algo i hm based on he ans o ma ion o solu ions
h ough inc emen s o he p e ious solu ion, he big di e ence is ha h ough he accep ance o
no o he solu ions his app oach a oids ge ing s uck wi h local min o max.
4. SA Pseudo Code
Gene a e an ini ial solu ion s0,
s = s0
8
sa is ac ion0 = i ness(da e, s)
While empe a u e > 0.1 do
s1 = Gene a e(s0, domain)
sa is ac ion1 = i ness(da e, s1)
I Accep (sa is ac ion0, sa is ac ion1,
empe a u e) hen
sa is ac ion0 = sa is ac ion1
s0 = s1
End I
empe a u e = empe a u e * cooling
End While
Re u n s0
• Gene ic Algo i hm (GA)
The Gene ic Algo i hm is based on Cha les Da win's heo y o e olu ion. I ac s on a se o
possible solu ions called indi iduals o a popula ion. The algo i hm s a s wi h an ini ial
popula ion and ans o ma ions a e pe o med on each o he indi iduals h ough mu a ion o
c osso e , whose decision is based on a p e iously de ined p obabili y. The bes indi iduals a e
chosen acco ding o an eli ism numbe o gene a e he new popula ion. The algo i hm ends when
he desi ed numbe o popula ions/gene a ions is eached and he bes indi idual om he las
popula ion is eached.
I should be no ed ha , acco ding o se e al s udies such as he one ca ied ou a he
Uni e si y o Neuchâ el in Swi ze land, i was ound ha hese algo i hms show be e esul s
wi h la ge popula ions han wi h inc easing he max numbe o gene a ions [16].
5. GA Pseudo Code
Ini ialize popula ion
eli e = elis ism * Popula ion-Size
Fo i in ange numbe _gene a ions
i ness(da e, indi idual) o each indi idual
in popula ion
Selec he eli e wi h he bes esul
Inse eli e in o new_popula ion
While new popula ion-size < Popula ion-Size
IF p obabili y o mu a ion
Mu a e eli e indi idual - > new
indi idual
ELSE
C osso e eli e indi duals -> new
indi idual
Inse indi idual in o new popula ion
End While
End Fo
9
Re u n las gene a ion bes ind idual
4.6 E alua ion
In o de o e alua e he pe o mance o each model, 10 uns o each one we e pe o med. Fo each
we e sa ed he sco e ob ained and he compu a ion ime equi ed. Fo he expe imen all he models
we e execu ed wi h da a based on he da e o May 5, 2021, aking in o accoun ha he domain
co esponds o a a iable ha would change day a e day, depending on eal needs o he hospi al.
No di e ence was pe cei ed in he success a e whe he conside ing 1 o 50 days.
Table 2 p esen s he me ics used o e alua ing he echniques as well as a b ie desc ip ion.
Table 2. Me ics
Me ic
Desc ip ion
A e age Fi ness_Func ion Sco e
Mean o all he sco es ob ained in he 10 Execu ions
A e age Run Time
Mean o he execu ion imes
Model Sco e S anda d De ia ion
(STD)
STD o he sco es ob ained
In a pe ec scena io, he alloca ion o beds co esponds o he daily needs o hese special ies and
he numbe o unused beds ends o 0. The maximum sco e ob ained would be 2 poin s o each
one o he 36 special ies, i.e. 2x36, meaning a maximum sco e o 72 poin s. I is necessa y o ake
in o accoun ha o his sco e o be eached he hospi al is no in a s a e o o e /unde capaci y.
All he beds would be occupied and alloca ed o he special ies co ec ly, which is no obse ed
in abou 99% o he occu ences.
The STD o he un ime was no eco ded since i was insigni ican di e ences among
uns o he same algo i hm, wha could be he esul o he compu a ional condi ions in he
de elopmen en i onmen .
5 RESULTS AND DISCUSSION
5.1 Algo i hm Se ings
To un he algo i hms conside ed in his s udy i was necessa y o de ine hei ini ial inpu
pa ame e s excep o HC. In he able 3 a e p esen ed he alues used o he implemen a ion o
each echnique.
Table 3. Algo i hms’ Pa ame e s
Model
Pa ame e s
Random Sea ch
Rounds ->10000
Hill Climbing
None
Simula ed Annealing
Cooling Ra e -> 0.95
Tempe a u e -> 10000000000
Gene ic Algo i hm
Popula ion-size -> 400
Numbe _Gene a ions -> 25
P obabili y o Mu a ion -> 0.2
Eli ism -> 0.2