BOOKS OF RtfiDIfGS - PAHO/WHO

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The Location Set Covering Model FACILITY
A possiblc otitcome oí gradually tiilictiilng ihe miaxini¡ill tithme ! .)CTION
constriintis is tit;li, at some point. tile p Itailities will hecome insufficient
in nuirilbe lo t oer r all points of- dcialudl withiiil tlhc timec (onstraint.
'I'he logical questiou t lh:t follows is, given tile time standlaríJd,
wliat is tihe leais niumnber of facilities required? This question lcd to
ite aot"".uIl;tisim
and solution of thle loatiorn set covelilg probllnim by
1'l'cls ct ¡,1 . 1:121. A stateimelt o1 tev plr)blcm is:
Fiidl tihe iniaiiurnuin t¡iiiinLber of fatliieis ¡ aiad lihcir lou.lio.nas suct la :
eJt I i. i lt ul dIci¡i1anld Ia;is 'a .ciliti) witilsis / tsllC u Isits.
iterestiniigly. several specialistsL ins ciiie:rtiiy hicailil services have
also posed this prob¡em, aliloghtil tlhey were unaw:;rc of ihe tractablle
niathiematical strtucture uitndcrlyiuig it. liitmley [34] ga;vec i(t lolow.
i"g verb.,Il It'illltCW)a
' :
Hlow nmasiy amlbulaictes? Arc li'tre riotiligh? 'l;lii is Jal .ICeCil ¡ehI: zC.
ispons¢ timie? Usually iti a inctiopolilan arel. i¡ is 15 nmiúitsl .... II
a 15 misnute responxs tinei il deiimallded. how mi;otv a:inmulances are rc.
quirrd; wlrrc muull rley bc Iosi(ioiuilt ¡1 ptu iu ;,;.l( alsla Ct
thal tihis criterion is nicie
The saiime undamental questionis were asked by (:assid)y and Wilson
in thlicis stmldy of thie l.oinlot Anmbilalile Se:vitc [3.iJ:
llow maity velCiclc; 1.aulId .It Seivi£c hlavc asid luow siOUhild tIíh I.ll
llcet be divid; *..'Cca .irceclicr auibula.igcs amad ithe vaJ¡iou s¡izs of
sittiitig