Business Process Simulation for Operational Decision Support

Transcription

1 Businss Procss Simultion for Oprtionl Dcision Support M. T. Wynn 1, M. Dums 1, C. J. Fidg 1, A. H. M. tr Hofstd 1, nd W. M. P. vn dr Alst 1,2 1 Fculty of Informtion Tchnology, Qunslnd Univrsity of Tchnology, GPO Box 2434, Brisbn QLD 4001, Austrli. {m.wynn,m.dums,c.fidg,.trhofstd}@qut.du.u 2 Dpt. of Mthmtics nd Computr Scinc, Eindhovn Univrsity of Tchnology, PO Box 513, NL-5600 MB Eindhovn, Th Nthrlnds. w.m.p.v.d.lst@tu.nl Abstrct. Contmporry businss procss simultion nvironmnts r grd towrds dsign-tim nlysis, rthr thn oprtionl dcision support ovr lrdy dployd nd running procsss. In prticulr, simultion xprimnts in xisting procss simultion nvironmnts strt from n mpty xcution stt. W invstigt th rquirmnts for procss simultion nvironmnt tht llows simultion xprimnts to strt from n intrmdit xcution stt. W propos n rchitctur ddrssing ths rquirmnts nd dmonstrt it through cs study conductd using th YAWL workflow ngin nd CPN simultion tools. 1 Introduction Businss procss simultion nbls th nlysis of businss procss modls with rspct to prformnc mtrics such s throughput tim, cost or rsourc utiliztion. A numbr of businss procss modlling tools support simultion to vrying dgrs [7]. Howvr, this tool support is lrgly grd towrds priori, i.., dsign tim, comprison of cndidt businss procss modls. Accordingly, thy ssum tht simultion xprimnts r run from n mpty initil stt, for vry lrg numbr of css, to giv nlysts insight into th vrg, long-trm bnfits of procss improvmnt options. This contrsts mrkdly with th rquirmnts of oprtionl dcision support, whr th gol is to vlut short-trm options for djusting n lrdy dployd businss procss in rspons to contxtul chngs or unforsn circumstncs. In this sitution, th currnt systm stt nd rcnt vnt history cnnot b ignord, nd th mphsis is on undrstnding th short-trm implictions of mking chng to th systm. Anothr shortcoming of contmporry procss simultion tools with rspct to oprtionl dcision support is th inbility to st diffrnt compltion horizons for simultion xprimnts. Th focus of trditionl simultion xprimnts is to idntify vrg long-trm bhviour, ovr wid vrity of contxtul scnrios. By contrst, oprtionl dcision mking introducs th nd to mk

2 short-trm dcisions, bsd on th currnt stt nd spcific rcnt history. To do this w nd th bility to limit th simultion s forwrd-looking horizon, to nbl rpid vlution of th consquncs of vrious dcisions. A typicl xmpl is th nd to dtrmin if rdploying rsourcs will limint tmporry bcklog of unprocssd jobs within givn tim frm. Simultion horizons of intrst includ bsolut tims (.g., 30 Jun 9pm), tim durtions (.g., 5 hours from now), th numbr of jobs compltd (.g., 200 th cs), nd th numbr of rsourcs consumd (.g., whn 80% of mploys r busy). In this ppr w dfin th rquirmnts for n oprtionl procss simultion nvironmnt which ddrsss ths issus, nd dscrib suitbl toolst rchitctur. To dmonstrt th fsibility of th concpt, w lso dscrib th outcoms of proof-of-concpt cs study prformd using xisting, off-th-shlf tools, th YAWL workflow ngin nd th CPN simultion tools. 2 Prvious nd rltd work Businss procss simultion involvs dvloping n ccurt simultion modl which rflcts th bhviour of procss, including th dt nd rsourc prspctivs, nd thn prforming simultion xprimnts to bttr undrstnd th ffcts of running tht procss [13]. In gnrl, businss procss simultion modl consists of thr componnts: bsic modl building blocks (.g., ntitis, rsourcs, ctivitis, nd connctors); ctivity modlling constructs (.g., brnch, ssmbl, btch, gt, split nd join); nd dvncd modlling functions (.g., ttributs, xprssions, rsourc schduls, intrruptions, usr dfind distributions) [13]. Businss procss simultion is rgrdd s n invlubl tool for procss modlling du to its bility to prform quntittiv modlling (.g., cost-bnfit nlysis nd fsibility of ltrntiv dsigns) s wll s stochstic modlling (.g., xtrnl fctors nd snsitivity nlysis) [4]. Simultion hs bn usd for th nlysis nd dsign of systms in diffrnt ppliction rs [13], dcision support tool for businss procss rnginring [6] nd for improving orchstrtion of supply chin businss procsss [12]. Simultion functionlity is providd by mny businss procss modlling tools bsd on nottions such s EPCs or BPMN. Ths tools offr usr intrfcs to spcify bsic simultion prmtrs such s rrivl rt, tsk xcution tim, cost, nd rsourc vilbility. Thy llow usrs to run simultion xprimnts nd to xtrct sttisticl rsults such s vrg cycl tim nd totl cost. Procss simultion cn lso b prformd using mor gnrl clss of simultion tchniqus known s discrt vnt simultion [13]. Evn though simultion is wll-known for its bility to ssist in long-trm plnning nd strtgic dcision mking, it hs not to dt bn considrd minstrm tchniqu for oprtionl dcision mking du to th difficulty of obtining rl-tim dt in th timly mnnr to st up th simultion xprimnts [8]. Nvrthlss, numbr for rcnt dvlopmnts point out how spcts of th problm cn b hndld, nd form th bsis of our pproch.

3 A novl us of discrt vnt simultion, clos to our own ims, is shortintrvl schduling of shop floor control systm whr th bility of th simultion to look hd t th xpctd prformnc of th systm in th nr futur, givn its currnt sttus, is usd to provid rl-tim rsponss to dynmic sttus chngs [3, 11]. W im to gnrlis this spcific cpbility to rbitrry businss modls. Mor significntly, Rijrs t l. [8], introducd th concpt of short-trm simultion. Thy wnt on to xprimnt with short-trm simultions from currnt systm stt to nlys th trnsint bhviour of th systm, rthr thn its stdy-stt bhviour [9]. A similr rsourc-orintd pproch is providd by th propritry Stffwr prdiction ngin 1. Our gol is to dsign such short-trm nlysis rchitctur in th contxt of widly-usd, off-th-shlf workflow tools, nd without th spcific focus on rsourcing. To do this, w hv xprimntd with combintion of th YAWL workflow ngin [1] nd th CPN Tools simultor [2]. A numbr of prvious such xprimnts hv informd our work. For instnc, Gottschlk t l. [5] usd YAWL subst to gnrt CPN modls, nd Vrbk t l. [14], intgrtd th ExSpct simultor with Protos 7.0 to provid modlling nd simultion fcilitis in on tool. Also, Rozint t l. [10] showd how vnt logs producd by CPN modls cn b mind to discovr th oprtionl chrctristics of th modl. Our im is to combin both ths notions, i.., crting simultion modls from workflow procsss nd fding bck simultion rsults to clibrt th modl, but with prticulr mphsis on incorporting obsrvd bhviours from th rl, oprtionl systm into th prdictiv simultion. 3 Rquirmnts for oprtionl procss simultion In this sction w us simpl xmpl to motivt th rquirmnts for oprtionl dcision support. Considr th crdit crd ppliction procss xprssd s workflow modl in Figur 1. Th procss strts whn n pplicnt submits n ppliction. Whn n ppliction is rcivd, crdit clrk chcks whthr th ppliction is complt. If th ppliction is found to b incomplt, th clrk rqusts dditionl informtion nd wits until th informtion is rcivd bfor procding. For complt ppliction, th clrk prforms furthr chcks to vlidt th pplicnt s incom nd crdit history. Th vlidtd ppliction is thn pssd on to mngr to mk th dcision. Th mngr dcids ithr to ccpt or rjct n ppliction. For n ccptd ppliction, crdit crd is producd nd dlivrd to th pplicnt. For rjctd ppliction, th pplicnt is givn timfrm to rqust rviw of th dcision. If rviw rqust is not rcivd, th procss nds. A typicl qustion for th crdit ppliction procss might b How long will it tk to procss crdit crd ppliction? Using convntionl tools for businss procss simultion, it is possibl to nswr this qustion with n vrg durtion, ssuming som typicl knowldg rgrding th vilbl rsourcs 1

4 Rciv info Rqust info Rciv crdit crd ppliction Chck for compltnss Prform chcks Mk dcision Notify ccptnc Dlivr crdit crd Notify rjction Tim out Rciv rviw rqust Fig. 1. Workflow modl of crdit crd ppliction procss nd xpctd xcution tims for th involvd ctivitis. Howvr, if th businss procss is lrdy oprtionl, nd it is supportd by workflow mngmnt systm, th sm qustion cn b skd for obsrvd, spcific stts of xcution. For instnc, w could sk ourslvs, how long will it tk to complt procssing prticulr ppliction, providd tht ll documnttion is complt nd th ppliction is now rdy for mngr to mk th dcision? Most importntly, this cn b don using th ctul stt of th systm s rsourcs, such s th numbr of clrks lrdy occupid with othr pplictions. Whil prforming short-trm systm prdictions, w nd to dfin whn simultion xprimnt should stop, i.., th compltion horizon. This cn b dfind s bound on vrious spcts of simultion, such s nd tims nd durtions, s wll s th numbr of cs compltions nd t vrious rsourc utilistion rts. For th crdit crd ppliction xmpl, som intrsting compltion horizons includ: 12 or 24 hours durtion from now; th tim t which th dly for dcision mking is ovr 3 dys; th point t which 1000 pplictions hv bn procssd, tc. Oprtionl dcision mkrs sking to djust th crdit crd procss following spiks in dmnd, or dlys cusd by unxpctd vnts, would bnfit from bing bl to prform simultions with diffrnt horizons. Considr for xmpl th cs whr th compny runs highly succssful promotion cmpign nd rcivs unxpctdly lrg numbrs of crdit pplictions. As rsult, th compny now hs bcklog of pplictions (.g., 100 pplictions) witing to b procssd. In this cs, th vrg tim (.g., fiv dys) to procss crdit crd ppliction cnnot b gurntd with th currnt numbr of stff mmbrs (3 clrks nd 1 mngr). At this stg, it is dsirbl to obtin mor rlistic input dt to dtrmin th cycl tim by tking into considrtion th currnt numbr of pplictions in th quu, nd othr obsrvbl proprtis of th liv systm. Undrstnding this cn ld to mor ffctiv rsourc plnning for th mngr. Givn th currnt stt of systm, th following qustions might b of intrst to mngr: 1. Wht is th cycl tim to procss n ppliction t this currnt lod? 2. Is it possibl for ll pplictions in th quu to b procssd ftr crtin durtion (.g., in 12 hours)?

5 3. Wht r th consquncs of dding fiv dditionl clrks nd two mngrs to ssist in procssing? Non of ths qustions cn b nswrd with prcision using th vrg rsults producd by convntionl simultion from n mpty stt. Ovrll, thrfor, th rquirmnts for n oprtionl procss simultion toolkit r: 1. Th bility to strt simultion from non-mpty stt, using dt obtind from th oprtionl systm s ctul bhviour. 2. Th bility to spcify (multipl) brkpoints in simultion xprimnt bsd on diffrnt critri such s th numbr of css compltd, th tim horizon, or bsd on conditions ncountrd in th simultd nvironmnt (.g., quu or rsourc utiliztion dropping blow prst lvls). 3. Th bility to utomticlly xtrct nd procss historicl xcution dt, nd in prticulr rcnt dt, in ordr to clibrt th simultion modl. 4 Architctur for oprtionl procss simultion In this sction, w first propos th gnric rchitctur for simultion nd thn discuss th vrious procss componnts to rlis this rchitctur. 4.1 Gnric rchitctur Figur 2 shows dt flow digrm of th proposd rchitctur s tool chin to support oprtionl procss simultion. Th procss modlling nd nlytics phs of th tool chin is concrnd with dvloping sttful simultion modl whil th procss simultion phs focuss on running vrious simultion xprimnts nd providing simultion rports s wll s dtild simultion logs for us s input into (r)dsign of th simultion modl. Th digrm shows stpby-stp trnsltion of simultion tmplt: first by nriching th tmplt with historicl dt to driv th vrious simultion prmtrs nd scond by including th strting stt to dvlop sttful simultion modl. Th rsulting sttful simultion modl is thn usd to run vrious simultion xprimnts. Th xtrnl input from obsrvd rl-world logs plys crucil rol in this rchitctur nd it is nvisiond tht numbr of xtrction functions will b usd to driv th historicl dt nd th strting stt from ths logs. Th rchitctur lso supports th us (nd convrsion) of simultion logs to driv historicl dt nd strting stt. Th min dt objcts (dpictd s hxgons) nd ctivitis (dpictd s rctngls) comprising th rchitctur in Fig. 2 r s follows. Simultion tmplt A simultion tmplt includs th rprsnttion of control, dt, nd rsourc rquirmnts of businss procss (procss dfinition) s wll s ncssry stup informtion for simultion xprimnts. To run simultion xprimnts, simultion tmplt dfins vrious input nd output prmtrs, brkpoints for compltion horizons nd drivtion functions. At

6 Procss Modlling & Anlytics [YAWL] Procss Simultion [CPN Tools] Simultion tmplt Instntit Simultion modl Add stt Sttful simultion modl Run simultion Historicl dt Strting stt Convrt stt Brkpoint stt Simultion log Convrt log Extrct history Extrct stt Obsrvd logs Fig. 2. Architctur of th oprtionl procss simultion toolkit minimum, simultion tmplt nds to spcify th following stup informtion: rrivl rts of css, rsourc clndr, simultion prmtrs (Ky Prformc Indictors), compltion horizons (brkpoints) nd simultion rport rquirmnts (monitors). Furthrmor, vrious prmtrs in th tmplt r lso nrichd with informtion on how to gnrt th dt usd in th simultion (stimtd or drivd). In our proposd rchitctur such prmtrs cn b spcifid ithr by ntring stimtions or by spcifying vrious drivtion functions ovr th obsrvd nd simultd log fils. For xmpl, th cs rrivl rt prmtr is typiclly spcifid ovr Poisson distribution. Similrly, th vrg xcution tim of tsk is spcifid using mn nd stndrd dvition. Abstrct dt typs for cs rrivl rts nd xcution tims in simultion tmplt cn b spcifid s follows: ArrivlRt : (ArrivlRtFunction HistoriclDt ArrivlRtFunction) ExcutionTim : Tsk (TimFunction HistoriclDt TimFunction) Instntition This ctivity tks simultion tmplt with drivtion functions nd historicl dt from th logs to gnrt simultion modl. It is ssntil tht log dt contins rlvnt informtion tht cn b usd for givn drivd prmtr. Obviously, th rquirmnts for logs could vry dpnding on givn prmtr nd th drivtion function usd. Th logs dt cn b bsd ithr on obsrvtions from running procss ngin or from prior simultion logs. Historicl dt Historicl dt to instntit simultion tmplt could b xtrctd from th xcution logs of procss ngin or from prvious simultion runs. For instnc, if n vrg xcution tim of tsk is to b drivd using log dt to clcult th mn nd stndrd dvition, th log should contin informtion bout whn ll instncs of givn tsk r xcutd nd compltd. If drivtion function is lso bsd on rsourcs (i.., th tim it tks to xcut tsk by mngr), thn th log should contin informtion bout rsourc utilistion in ddition to tim. Convrsions nd djustmnts might b ncssry if log dt is incomptibl with th rquirmnts in th tmplt.

7 Ths convrsions tk plc during th Extrct history ctivity for obsrvd logs nd th Convrt log ctivity for simultion logs. Th ncssry bstrct dt typ for log to driv cs rrivl rt nd xcution tims is s follows: Css : Cs CrtionTim CnclltionTim CompltionTim CompltdTsks : Cs Tsk StrtTim EndTim Rsourc Obsrvd logs nd Simultion logs Whil th obsrvd logs rprsnt th dt nd mtrics from xcuting procss ngins, th simultion logs provid th informtion from prior simultion runs. Both typs of historicl dt r usful in dtrmining pproprit vlus for simultion prmtrs. Simultion modl Aftr nsuring tht ll drivbl simultion prmtrs hv bn instntitd with historicl dt, simultion modl is gnrtd. It is now possibl to us this simultion modl to run simultions from th initil stt. Adding stt This ctivity tks simultion modl nd givn stt to st th strting stt of simultion xprimnt. If simultion xprimnt is to b strtd from scrtch (n mpty stt), miniml trnsformtion is rquird to includ rsourc scnrio for simultion xprimnt. On th othr hnd, if simultion xprimnt is to b strtd from givn stt, currnt stt informtion is ddd to obtin sttful simultion modl. In css whr som of th tsks r lrdy running for crtin mount of tim in th simultion s strting stt, w propos to us trunctd probbility distribution so tht th durtion rndomly ssignd to n ctiv tsk during th simultion is lwys grtr thn th mount of tim for which th tsk hs lrdy bn running. Strting stt Th stt informtion cn b drivd from historicl logs nd lso from prior simultion runs. At minimum, th logs usd to driv stt should contin informtion on ctiv css, rsourc vilbility nd ctiv nd nbld tsks informtion. Inconsistncis r possibl btwn givn modl nd th dt obtind from th logs nd convrsions might b ncssry. Th following bstrct dttyps for logs cptur th minimum informtion rquirmnts to gnrt n initil simultion stt: ActivCss : Cs CrtionTim ActivTsks : Cs Tsk StrtTim Rsourc EnbldTsks : Cs Tsk RsourcAvilbility : Rsourc Rol LogTim : Tim Importntly, this llows us to injct obsrvd chrctristics of th systm into th simultion. For instnc, lt s ssum simultion modl my spcify th (initil) vilbility of thr stff mmbrs, whrs th obsrvd logs show thr r ctully fiv stff mmbrs currntly ssignd to this procss.

8 Brkpoint stt Cpturing th full stt of th simultion modl t th nd of simultion xprimnt provids n opportunity to us th brkpoint stt s th initil stt for nothr simultion, thus fcilitting th conduct of simultion xprimnts with diffrnt brkpoints. Sttful simultion modl A sttful modl is obtind by nriching simultion modl with strting stt informtion for simultion runs. Mor thn on sttful simultion modl cn b dvlopd whr ch on rprsnts th stt t crtin point in tim. Th LogTim prmtr from th stt is usd to st th strting tim of th simultion xprimnts. Running th simultion Simultion xprimnts cn now b strtd using sttful modl nd stoppd t vrious compltion horizons. In ddition to th gnrtion of simultion rports for nlysis, th rchitctur mks provision for th gnrtion of both brkpoint stts nd simultion logs. This dt cn thn b usd s input for ltr simultion runs ftr ncssry convrsions. 4.2 A prcticl instntition of th rchitctur It is possibl to rlis th proposd simultion rchitctur in numbr of wys using suitbl procss ditor, procss ngin (with logging functionlity) nd simultion tool tht is flxibl nough to support our rquirmnts. For our rsrch, w r using th YAWL workflow nvironmnt for both modlling nd nlytics componnts nd th simultion cpbilitis within CPN Tools for procss simultion, s shown by th prtition in Fig. 2. Th YAWL workflow nvironmnt ws chosn bcus of its forml foundtion in Ptri nts, its xprssivnss in providing support for workflow pttrns, its sy-to-us grphicl ditor tht hs th bility to gnrt xcutbl procss modls, nd its xtnsiv logging function for procss xcution. Thr r lso mppings vilbl btwn vrious businss procss modlling nottions (EPC, BPMN, BPEL) nd Ptri nts. Furthrmor, th YAWL workflow lngug is supportd by n opn-sourc implmnttion 2. Th YAWL ditor is n idl cndidt for th procss modlling componnt in th rchitctur s th usr cn spcify control, dt nd rsourc rquirmnts of businss procss using nturl grphicl nottion nd thn xport th procss dfinition s n XML fil rdy for xcution in th ngin. Vrious vrifiction functionlitis r lso vilbl in th ditor to nsur th corrctnss of th procss modl bfor xcution. Th YAWL ditor cn b sily xtndd to cptur vrious stup prmtrs for simultion tmplt. Th logging modul in th YAWL ngin cn b usd to rcord th sttistics of vrious css (such s th strt nd nd tims, th rsourc, whthr th tsk is cnclld or compltd, tc). Ths logs provid sufficint informtion to gnrt sttful simultion modls. Th currnt YAWL implmnttion dos not provid simultion functionlity. Howvr, it is rthr strightforwrd to trnsform YAWL modls into 2

9 Colourd Ptri Nts (CPNs) [2], modulo som rstrictions, nd to xploit th simultion cpbilitis of CPN Tools 3. Colourd Ptri nts cn b usd to modl Ptri nts with tim constrints nd hirrchy. In contrst to contmporry BPM simultion tools, CPN Tools cn b customisd to support our rquirmnts, i.., th bility to strt simultion xprimnts from givn stt nd th spcifiction of diffrnt compltion horizons using brkpoints. It is possibl to incorport th log dt by spcifying drivtion ruls using ML functions. Rthr thn modlling th businss procss dirctly in CPN Tools (i.., modlling th procss s on or mor Colourd Ptri nts), our rrngmnt voids th nd for dtild knowldg of Ptri nts, which would mk CPN Tools unsuitbl for businss procss dsignrs. For ths rsons, w combin us of YAWL for modlling nd xcution of businss procsss with CPN Tools for BPM simultion, to lvrg thir strngths in thir rspctiv rs. 5 Proof of concpt To vlidt th simultion rchitctur, w dvlopd sttful simultion modl for th crdit crd ppliction procss from Sction 3 nd prformd simultion xprimnts using th CPN Tools. Th crdit crd ppliction workflow procss from Fig. 1 ws (mnully) trnsltd into corrsponding hirrchicl nd timd colord Ptri nt s dpictd in Fig. 3. Th trnsltions r similr to th Gottschlk t l. s pproch [5] whr YAWL condition is mppd to CPN plc nd YAWL tsk to CPN substitution trnsition (s th Mk dcision tsk Fig. 4). As th crdit crd procss dos not contin tsks with complx split nd join bhviours, w lctd to mp most YAWL tsks to CPN trnsitions dirctly for simplicity. Th Environmnt subpg controls th rrivl of css. Tokns in th rsourc plc indicts th numbr of mploys vilbl to xcut th tsks (.g., clrks nd mngrs). Excution tims for tsks wr spcifid using ML functions nd tim dly ws ttchd to th tsk (.g.,@ + gtexct im(mn = 7200, stdd = 3600)). In Fig. 4, th XOR-split bhviour of th tsk is modlld s two trnsitions tht shr th sm input plc (busy). Th strt trnsition for th Mk dcision tsk hs nothr input from th rsourc plc with gurd to tht only mngr cn crry out this tsk ([#rol() = mgr]). To dtrmin th fsibility of th proposd rchitctur, w tstd out th rsourc plnning scnrio s discussd in sction 3. For tsting purposs, th sttful simultion modl is popultd with th following dt. cs rrivl rt of 1 ppliction pr hour following Poisson distribution; 100 ctiv css s th strting stt whr 80 crdit crd pplictions r in th rdy plc, 15 in th complt chck plc, 3 in th rciv plc, 1 in th ccpt plc nd 1 in th busy plc of th Mk dcision tsk; brkpoint monitors with 12-hour nd 24-hour tim horizons nd mrking siz monitors to obsrv th two plcs of intrst, th rdy plc nd th complt chck plc; 3

10 nvironmnt Environmnt strt stdd=68400}) Rciv ppliction Rciv info rdy rsourc EMP Chck compltnss Chck compltnss [#rol()=clrk] Prform chck complt chck rqust Rqust info Mk dcision Mk dcision rjct ccpt Notify Notify witrviw snd Rciv rviw Tim out Dlivr @ nd Fig. 3. CPN modl of crdit crd ppliction procss complt chcks In [#rol()=mgr] Strt rsourc I/O EMP busy BUSY (,) (,) Don rjct Don ccpt rjct Out ccpt Out Fig. 4. CPN subpg for mking crdit crd dcision

11 xcution tims (smpl mn nd stndrd dvition) for ch tsk; nd two rsourc vilbility scnrios, nmly 5 clrks nd 1 mngr, nd 10 clrks nd 3 mngrs. Multipl simultion runs r crrid out using th strting stt with 100 ctiv css, two diffrnt tim horizons (12 hours nd 24 hours) nd with two diffrnt rsourc scnrios. Th rsults (s Tbl 1) show tht whn procssing th pplictions with 5 clrks nd 1 mngr, on vrg (with 95% probbility) btwn 48 to 55 pplictions r still in th quu in th rdy (R) plc nd btwn 17 to 28 in th complt chck (C) ftr 12 hours nd it bcoms (R) nd (C) ftr 2 24 hours. On th othr hnd, th quu is rducd to 12-20(R) nd 3-9 (C) ftr 12 hours, nd 10-17(R) nd 0-2(C) whn 10 clrks nd 3 mngrs r vilbl. This scnrio illustrts th possibilitis opnd by oprtionl procss simultion, in trms of bing bl to prform wht-if nlysis bsd on th currnt sitution nd to diffrnt compltion horizons. Tbl 1. Summry of simultion rsults Rsourc vilbility Durtion (12 hours) Durtion (24 hours) 5 clrks nd 1 mngr (R) nd (C) (R) nd (C) 10 clrks nd 3 mngrs (R) nd 3-9 (C) 10-17(R) nd 0-2 (C) In this proof-of-concpt dmonstrtion w wr spcificlly intrstd in vlidting th fsibility of insrting non-mpty strting stt nd multipl compltion horizons into simultion xprimnts. For instnc, w ssumd n rrivl rt of 1 ppliction pr hour instd of driving th ctul rrivl rt for ths obsrvtions. Nvrthlss, w hv confirmd tht th YAWL ngin logs contin sufficint dt to instntit th simultion tmplt nd to dd stt. Th sm gos for th rsourc vilbility sttistics nd th currnt stt. In th nxt stg, w pln to implmnt th ncssry xtrction nd convrsion functions to driv simultion prmtrs nd strting stts utomticlly from logs. 6 Conclusion nd futur work To produc ccurt short-trm prdictions workflow simultion nvironmnt must strt its nlysis in stt tht incorports th ctul, obsrvd proprtis of th oprtionl systm, including its rcnt history. In this ppr w hv dmonstrtd th fsibility of building such simultion nvironmnt using offth-shlf workflow modlling nd systm simultion tools. A gnrl dsign for such systm ws dfind in trms of its ssntil cpbilitis nd (mnul) fsibility study ws conductd using th YAWL nd CPN Tools toolkits. Currntly w r implmnting th vrious gluing componnts ndd to utomt th trnsformtion of mind log vlus to produc simultion inputs. Acknowldgmnt This rsrch ws fundd by th Austrlin Rsrch Council grnt DP ,

12 Rfrncs 1. W.M.P. vn dr Alst nd A.H.M tr Hofstd. YAWL: Yt Anothr Workflow Lngug. Informtion Systms, 30(4): , Jun M. Budouin-Lfon, W. Mcky, P. Andrsn, P. Jnck, M. Jnsn, H. Lssn, K.Lund, K.Mortnsn, S. Munck, A. Rtzr, K. Rvn, S. Christnsn, nd K. Jnsn. A Tool for Editing nd Simulting Colourd Ptri Nts. In ETAPS 2001, volum 2031 of LNCS, pgs , Gnov, Itly, April Springr-Vrlg. 3. G. Drk, J. Smith, nd B. Ptrs. Simultion s plnning nd schduling tool for flxibl mnufcturing systms. In Procdings of th 27th confrnc on Wintr simultion, pgs , G. Giglis, R. Pul, nd G. Doukidis. Simultion for intr- nd intr-orgnistionl businss procss modlling. In Procdings of th 28th confrnc on Wintr simultion, pgs , F. Gottschlk, W.M.P. vn dr Alst, M.H. Jnsn-Vullrs, nd H.M.V. Vrbk. Protos2CPN: Using Colord Ptri Nts for Configuring nd Tsting Businss Procsss. In Workshop nd Tutoril on Prcticl Us of Colourd Ptri Nts nd th CPN Tools, Arhus, Dnmrk, Octobr Publishd onlin t: 6. V. Hlupic nd S. Robinson. Businss procss modlling nd nlysis using discrtvnt simultion. In Procdings of confrnc on Wintr simultion, volum 2, pgs , M. Jnsn-Vullrs nd M. Ntjs. Businss procss simultion tool survy. In Workshop nd Tutoril on Prcticl Us of Colourd Ptri Nts nd th CPN Tools, Arhus, Dnmrk, Octobr Publishd onlin t: u.dk/cpnts/workshop06/. 8. H.A. Rijrs nd W.M.P. vn dr Alst. Short-trm simultion: bridging th gp btwn oprtionl control nd strtgic dcision mking. In Procdings of th IASTED Confrnc on Modling nd Simultion, pgs , Phildlphi, USA, Hjo A. Rijrs. Dsign nd Control of Workflow Procsss. Springr-Vrlg Nw York, Inc., Scucus, USA, A. Rozint, R. Mns, nd W.M.P. vn dr Alst. Mining CPN Modls: Discovring Procss Modls with Dt from Evnt Logs. In Workshop nd Tutoril on Prcticl Us of Colourd Ptri Nts nd th CPN Tools, Arhus, Dnmrk, Octobr Publishd onlin t: J. Smith, R. Wysk, D. Sturrock, S. Rmswmy, G. Smith, nd S. Joshi. Discrt vnt simultion for shop floor control. In Procdings of confrnc on Wintr simultion, volum 2, pgs , Lk Bun Vist, FL, Dcmbr T.W. Twoldbrhn, A. Vrbrck, nd S. Msnjil. Simulting procss orchstrtions in businss ntworks: cs using BPEL4WS. In Procdings of th 7th intrntionl confrnc on Elctronic commrc, pgs , Nw York, USA, ACM Prss. 13. Krim Tumy. Businss procss simultion. In Procdings of th 28th confrnc on Wintr simultion, pgs 93 98, H.M.V Vrbk, M. vn Httm, H. Rijrs, nd W. Munk. Protos 7.0: Simultion md ccssibl. In Procdings of ATPN 2005, volum 3536 of LNCS, pgs Springr, 2005.