Comparison of workflow software products

Transcription

1 Internatona Conference on Computer Systems and Technooges - CompSysTech 2006 Comparson of worfow software products Krasmra Stoova,Todor Stoov Abstract: Ths research addresses probems, reated to the assessment of software products, used for the desgn and expotaton of worfow management systems The attenton s drawn towards the assessment and comparson of such software suts The ac of drect quanttatve evauatons of the products nssts to assess and compare the products The probem soved s the mnmzaton of the subectve nfuence of the experts n ther persona evauaton fndngs An dea to overcome ths probem s to appy a common evauaton scheme, whch s based on obectve requrements towards the products Key words: web servces, worfow systems, automaton, busness processes INTRODUCTION To mpement automaton technques and contro methods n the busness processes t s necessary to appy modeng technques for the non-technca and organzatona systems and to extend the functonates of the nformatona computer drven systems n the organzatons Over the ast decade there has been ncreasng nterest n nformaton systems that are used to support, contro, and/or montor busness processes Typca exampes of systems drven by mpct or expct process modes are Wor Fow anagement Systems (WfS), Enterprse Resource Pannng (ERP) systems and Customer Reatonshp anagement (CR) systems These systems can be confgured to support specfc busness processes Severa anguages have been proposed to support process-orentaton n the context of web servces (BPEL4WS /Busness Process Executon Language for Web Servces/, BPL /Busness Process odeng Language/, WSCI, etc) The support of IB, crosoft, HP and SAP for a anguage e BPEL4WS [1] renforces the fact that process-awareness has become one of the cornerstones of nformaton systems deveopment Exstng anguages and toos focus on contro-fow and combne ths focus wth mature support for data n the form of XL and database technoogy As a resut, contro-fow and data-fow are we addressed n anguages and systems: BPEL4WS [1], XPDL (XL Processng Descrpton Language) [2] The technooges n scope are those defned by standardzaton bodes and ntatves as BPI (Busness Process anagement Intatve) [3], ebxl (Eectronc Busness usng extensbe arup Language) [4], OASIS [5], WfC [2] and W3C [6] A smart technoogy anayss and comparson s requred to mae the rght technoogca decsons, and n partcuar from two ey aspects that mpact the entre fecyce of any ebusness deveopment: the choce of a choreography and orchestraton anguage These two anguages are centra to the specfcaton and executon of a worfows: Choreography s concerned wth goba, mutparty, peer-to-peer coaboratons where busness enttes nteract n ong-ved statefu and coordnated fashon regardess of any programmng mode or supportng patform used Choreography anguages (eg BPSS /Busness Process Specfcaton Schema/, WS-CDL /Web Servces Choreography Descrpton Language/, etc) cannot be drecty executed and have to be transated to an orchestraton anguage n order to be executed Orchestraton focuses on the behavour of a snge busness entty - t s a hub and spoe mode where a controer resdng at a snge ocaton ocay enforces the progress of a process by foowng ts defnton Orchestraton anguages (eg BPL, BPEL /Busness Process Executon Language/, XPDL, BPELJ, PDL, etc) are executabe anguages and defne a runtme envronment for ther executon

2 Internatona Conference on Computer Systems and Technooges - CompSysTech 2006 Choreography and orchestraton express the operatona semantcs of busness enttes nvoved n dstrbuted servces and compement each other Choreographes transate goba worfows between busness enttes whe orchestratons transate oca worfows to a busness entty Goba worfows concern the exchange of messages between peers wthout any centrazed contro Loca worfows can be ether externa or nterna to a gven entty Externa oca worfows defne the pubc externa behavour of a snge entty and dffer between entty s roes Interna worfows are hdden from the outsde and they mpement externa worfows Worfows can be organzed herarchcay n a way that a partcuar actvty of a worfow coud tsef be reazed by a more specfc worfow Choreography and orchestraton anguages can be ether graphca (eg BPN, UL /Unfed odeng Language/, etc) or textua (BPSS, WS-CDL, BPL, BPEL, etc) Aternatve anguages exst for both choreography and orchestraton Some can be used for both, athough ther centre of gravty woud be ether around choreography or around orchestraton Orchestraton anguages are typcay hgh-eve specazed programmng anguages athough some anguages or anguage extensons go much coser to genera-purpose programmng anguages e JSR207 and PDL that factates the programmng of busness worfows drecty n Java, or BPELJ that aows ntegratng Java code (snppets) drecty n BPELJ code Athough they can be ntay cassfed, these anguages refer to dfferent concepts accordng to ther own creators They are named for nstance executon anguage, modeng anguage, defnton anguage, descrpton anguage, etc Understandng the exact dfferences between a these anguages, ther precse scope, ther appcabty to any proect and evauatng whch w emerge, s not an easy tas Choosng the rght anguage(s) s not the ony chaenge as many other technooges are aso nvoved For nstance, the format of the messages (usuay based on XL) exchanged between the worfow engnes offers aso a choce between varous specfcatons, eg UBL, BPS, RosettaNet nterfaces, OAGIS nterfaces, etc Another exampe s the choce between communcaton protocos used between worfow engnes, that can fuf very dfferent roes, eg SOAP, whch s a synchronous access protoco based on XL, ASAP (asynchronous protoco but over SOAP), BTP (transacton protoco supportng atomc operatons and runnng over SOAP), or Wf-XL (specazed protoco but over ASAP and provdng management of worfow engnes), etc The paper contans an anayss concernng the choce of software products, supportng worfow functonates A speca emphass s done on the comparson of exstng Open Source software supportng the dfferent technooges ethodoogy for comparson of the worfow software products A sut of 134 software products are dentfed, concernng the worfow management doman [7] These products address dfferent area of system appcatons (scentfc systems, busness systems) and they have dfferent eve of maturty, functonaty, usabty The evauaton process has to tace a methodoogca probem whch orgns from the fact that dfferent experts assess dfferent products The quafcaton of the experts, ther experence, the varety of the worfow software products, and the ac of common evauaton methodoogy a these factors can strongy nfuence the resuts of the product evauaton A second methodoogca probem arses for the evauaton fndngs how to quantfy the evauaton resuts to generate a common scae for products comparson Ths scae s necessary to support the decson mang process for fndng good quaty and prospectve software products The paper presents a methodoogy for evauaton and comparson of the software products The theoretca bacground s founded on consderaton to mnmze the nose

3 Internatona Conference on Computer Systems and Technooges - CompSysTech 2006 nfuences, whch tae pace n a contro and management systems The forma consderatons are gven beow The foowng notatons are used: A assessment rate of software product, =1,N; N number of tested and evauated products; ε - evauaton error, performed by expert durng evauaton of product, =1,N; number of experts, evauatng the software products; ε - error, whch orgns from the methodoogca approach, apped for the assessment of the worfow software products The dea case w be when the expert dentfy the quaty of the software product ust as ts dea assessment vaue A Unfortunatey, the bacground of the expert nfuences the evauaton fndngs by hs error of ncompetence ε An addton nose nfuence ε comes from the methodoogy apped for the product assessment Hence the rea evauaton vaues about the quaty of the product s: RA A + ε + = ε (1) The evauaton methodoogy has to mnmze the nfuence of ε by means that the worng estmatons RA have to tend towards the rea vaue of the product quaty A Because the nose ε are not measurabe, durng the evauaton process they have to be ept mnma f ths s possbe The evauaton methodoogy s based on a common standard, concernng the quaty of software products Thus the standardzaton approach targets the mnmzaton of the expert subectve nfuence to the evauaton fndngs The evauaton methodoogy provdes a common evauaton bacground for a experts Thus the nose ε whch arses from the methodoogca evauaton scheme w be equa to a evauaton fndngs accordng to (1) The next mprovement comes from the forma descrpton (1) The dea s not to use the absoute vaues of the rea assessment RA, but to mae a reatve comparson between the evauated products It means that f product s assessed accordng to (1), hence the product w have anaogca assessment RA : RA = A + ε + ε But for mang a quaty assessments of the products, the dfference Δ, = RA RA has to be consdered The beneft of usng Δ, nstead of RA and RA comes from the dfference: Δ = RA RA = A + ε + ε ( A + ε + ε ) = A A + ( ε ε ), Thus havng the dfferences between the products,,, t foows: Δ = A A + ( ε ε ), Δ = A A + ( ε ε ) (2),, If Δ, > Δ, t can be strongy confrmed that the software product s more quafed than product Ths resut s nfuenced by the errors of the expert evauatons ε, ε, ε However, assumng that durng the evauatons the expert quafcaton rses, then the errors vansh: m ε ( t) 0, = 1, N, = 1, N (3) t An advantage of the cassfcaton scheme (2), based on reatve assessments Δ,, comes from the fact that the error ε, orgnated from the evauaton scheme, dsappears Ths

4 Internatona Conference on Computer Systems and Technooges - CompSysTech 2006 s mportant havng n mnd that absoute evauaton scheme s dffcut to desgn Addtona beneft of the scheme (2) n comparson wth the assessment scheme (1) comes for the expert evauaton bacground For the scheme (1) the fna evauaton RA s drecty nfuenced by the expert ncompetence ε For the scheme (2) the fna evauaton Δ, s nfuenced by the subtracton of the two ncompetences ε It means that f the ncompetence of the evauator s the same for the dfferent products, the ntegra error ε ε vansh, whch s benefca for the evauaton process For the case when two experts and m have to assess dfferent products, the m evauaton scheme Δ, s nfuenced by the ncompetence of the both expertsε But these nds of ncompetence are subtracted for the overa evauaton to Δ, Thus, for the fna evauaton ratng Δ, accordng to scheme (2), the ncompetence of the evauators nfuence sower the fna resut when the errors are from the same sgn, n comparson to the absoute evauaton scheme, resdng on (1) Consequenty, the reatve assessment of the products, foowng (2), has three genera benefts: - the error ε from the evauaton methodoogy s suppressed; - the evauaton fndngs are nfuenced by the dfference of the evauator s ncompetence, not from ther absoute vaues; - for the experts, accordng to ther rea wor durng the test of the software products, the absoute ncompetence vansh: m ε ( t) 0, = 1, N, = 1, t - Foowng these theoretca fndngs for the assessment of the software products, the evauaton can be performed n the foowng order: - Desgn of a common evauaton tempate for the assessment of the quaty of the software products; - To derve approprate quatatve scheme for the quaty of the products Partcuary, a quantfcaton scheme has to be apped for the estmaton of the reatve assessments RA, =1,N for each product The resuts of these estmatons have been presented as pe- chart dagrams; The common evauaton tempate for assessng the software product can be desgned based on ISO/IEC 9126 standard for the quaty of the software product The tempate has to contan the evauaton categores: 1Genera categores (G): Worfow software overvew wth sub-categores G11 Worfow software presentaton G12 Worfow software descrpton G13 Category of the software product G14 Supported nterfaces G15 Supported standards Confrmng standards and exchange formats 2 Functona categores (F): Prncpe functons F1 odeng process defnton F2 Smuaton, debug F3 Executon worfow engne F4 Worfow cent appcaton F5 Integraton wth other worfow engnes Supported standards F6 Admnstraton and montorng FA Auxary functons: statstcs, regstraton, country area nformaton, hep functonates 3 Reabty 4 Usabty

5 Internatona Conference on Computer Systems and Technooges - CompSysTech Effcency 6 antanabty 7 Portabty 8 Externa metrcs The dfferent categores can be addtonay decomposed to gve hnts to the evauators by means to decrease the vaues of the ncompetence ε Evauaton Fndngs The evauatons are dvded nto sx genera crtera, reated to the man software quaty categores: functonaty, reabty, usabty, effcency, mantanabty and portabty The evauatons of the functonates of the products have quatatve nature They expan and summary the standardzaton bacground of the product, ts features to cooperate wth other software products, the possbty to mode, smuate, manage and admnster the worfow management processes The evauaton fndngs are resut from nstaaton, confguraton and tra test The evauaton s gven by drect test wth the product An ntegra evauaton has been performed by gvng expert ranng for every software quaty subcrtera Four-eve scae has been chosen: wee, good, strong, can t assess/not appcabe, whch formaze the expert opnon for the approprate quaty subcrtera A partcuar evauaton fndng for the man quaty crtera functonaty s presented n fg1 for the worfow product Actve BPEL Engne Actve BPEL Engne Characterstcs can t score wea good strong ISO/IEC 9126 assess resut Functonaty 20% 20% 60% 4,8 Reabty 75% 25% 4,5 Usabty 50% 12,5% 37,5% 2,75 Effcency 67% 33% 2,68 antanabty 60% 20% 20% 3,6 Portabty 20% 60% 20% 4,4 Fg1 Evauaton fndngs for the product Actve BPEL Engne

6 Internatona Conference on Computer Systems and Technooges - CompSysTech 2006 CONCLUSIONS The methodooges used for the evauaton of software products and nformaton resources are strongy nfuenced by subectve reasons These nfuences orgn from the evauaton methodoogy, the choce of the crtera, the ncompetence of the experts, the users expectatons of the software products To mnmze these subectve nfuences, the paper gves preferences to a standardzaton approach performng a comparson of the products accordng to the recommendatons of the standard ISO/IEC9126 for assessng the quaty of the software product Usng the man categorzaton scheme for quaty assessment of the software product, an evauaton tempate s deveoped Thus, usng a common evauaton scheme, the evauatons mnmze the drawbac that dfferent evauators have to evauate dfferent software products The common evauaton scheme and the derved tempate are prerequstes for mnmzng the evauaton errors A comparatve evauaton scheme s deveoped It aows mnmzaton of the evauaton errors, orgnatng from the methodoogca drawbacs of the evauaton scheme and from the persona ncompetence of the dfferent evauators A reatve assessment and comparson s wored out The quaty of the products are assessed by absoute evauaton, mared e RA Pe-chart dagrams refect these quaty assessments The evauaton was used for the deveopment of the FP6 proect: Vrtua Internet Servce Provder (VISP), funded by the European Commsson REFERENCES [1] Andrews T, F Curbera, H Dhoaa, Y Goand, J Ken, F Leymann, K Lu, D Roer, D Smth, S Thatte, I Trcovc, and S Weerawarana, Busness Process Executon Language for Web Servces Verson 11, 2003 Technca report, Accessed at BPELv11-ay052003Fnapdf [2] WfC, Worfow Process Defnton Interface XL Process Defnton Language Technca Report Document Number WFC-TC-1025, Worfow anagement Coaton, 2002, [3] Usng BPN to ode a BPEL Process; Stefan A Whte; arch 2005 [4 [5] OASIS: Web Servces Busness Process Executon Language; Commttee Draft; Verson 20; December 2005; avaabe at: Dec htm [6] W3C: Web Servces Addressng; W3C ember Submsson; August 2004; avaabe at: [7] Proect FP VISP D22 Worfow software anayss and comparson, February 2006 ABOUT THE AUTHOR AssocProf Krasmra Stoova, DSc,PhD, Insttute of Computer and Communcaton Systems, Bugaran Academy of Scences, Phone: , Е-ma: stoova@hsccsbasbg Prof Todor Stoov, DSc, PhD, Insttute of Computer and Communcaton Systems, Bugaran Academy of Scences, Phone: , Е-ma: todor@hsccsbasbg