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

Lobo, Afonso Augusto Paula; Barbosa, Agostinho; Guimarães, Tiago André Saraiva; Lopes, João; Peixoto, Hugo; Santos, Manuel

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.

Full text

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