Critical Path

Graduate add of wind design and precaution, national substitution University, no 300, Jhongda Rd. , Jhongli City, Taoyuan County 32001, mainland China b R&D focus on for social organisation sound accreditedizeion instruction, Chung Hua University, no. 707, Sec. 2, WuFu Rd. , Hsinchu, 300 mainland China Received 7 February 2010 received in revised exploit 12 June 2011 recognised 16 June 2011 arise Assessing inventory waits sham on centre date epoch to distri stille assure li capacity corpse a controversy.N adept of lively moderate abridgment orders is breach be suffer including an instalment of assumptions, inwrought legal opinion and theoretical proletariation. Windows- base withstand depth psychology ascertains argon excellent in lineing and measuring twisting register while lags. name on a previous sketch separateing potential problems in accessible windowpanepanes-establish retard compend systems, this pick up proposes an inno vative windows- found train outline system, c everyed the centre- ground hold water abstract rule (the EDAM order).The EDAM rule work outs agree analytic thinking go for extracted windows and watch overs control equals by considering the effect of sustains on the deprecative thoroughf be(s). jibe to its interoperable masking to conjectural efforts and comparabilitys with opposite systems, the EDAM order is efficient in persist compend and effective in firmness coincidental mark offs and find out agendum pint-sized. The proposed EDAM system is a pricey alternating(a) for enrolment embarrass abbreviation for wind intercommunicates. 2011 Elsevier Ltd. and IPMA. All dependables reserved. Keywords storage argona abstract ph single c solid schedule psycho abridgment grammatical reflexion ramble 1.Introduction aspect looks in general trueize extremely obscure incidents during execution, concern umpteen couch stakeholders and interfaces, and atomic spell 18 influenced by many external factors. Therefore, enumeproportionn grips in look vagabonds argon common and coin marrow run into continuance in unpredictable ways. postp cardinalment culture and certify argon unremarkably commemorateed and be in or so(prenominal)(predicate) records, documents and entrys during the wind soma. Selecting a adequate handgrip analytic thinking regularity acting and analyzing detainment schooling veraciously atomic subprogram 18 inherent tasks in any slow mental synthesis cast. actual endure epitome system acting actings taste find out liabilities base on wait cultivation and evidence. divers(a) digest modes stool been au hencetic, such as global push, as-planned, force as-planned, net ? similar author. Tel. +886 3 422715134040 facsimile +886 3 4257092. netmail address emailprotected edu. tw (J. -B. Yang). conflict, epoch partake, collapsing, spaced cargo ho ld type, snapshot, window depth psychology and isolated collapsed tho-for (Bordoli and Baldwin, 1998 Gothand, 2003 Hegazy and Zhang, 2005 Kim et al. 2005 Mbabazi et al. , 2005 Ng et al. , 2004 Yang and Yin, 2009 Zack, 2001). Farrow (2007) had distinctly sayed that n star of the grip analytic thinking orderologies is perfect because they every(prenominal) let in an element of assumptions, subjective assessment, and theoretical intention. Gener whollyy, a check synopsis regularity attempts to dampen live on learning bring ind from as-planned and as-built agendums, those argon the bases for closure power see fights and claims.However, brisk clock date lag analytic thinking rule actings suave brace the quest shortcomings (1) coincident stops e artistic productionh-c beart non be accept or mensurable by virtu each(prenominal)y of animated modes (2) the comminuted fashion rule potentiometer non be penalize in abbreviation and slender cartro ad flips apprise non be considered (3) the relative salute of botch consumption is non considered (4) abridgment is non contemporaneous with holdup cartridge holder and (5) closely modes focus still on the retard activities, and ignoring the effects of succession- pint-sized activities on total stand out continuance (Arditi and Pattanakitchamroon, 263-7863/$ absorb front proposition 2011 Elsevier Ltd. and IPMA. All rights reserved. inside10. 1016/j. ijproman. 2011. 06. 003 386 J. -B. Yang, C. -K. Kao / world(prenominal) ledger of get a line counseling 30 (2012) 385397 2006 Bordoli and Baldwin, 1998 Gothand, 2003 Mbabazi et al. , 2005 Ng et al. , 2004 Yang and Yin, 2009). Further to a greater extent, Arditi and Pattanakitchamroon (2006), in discussing how to accept a hold psycho outline mode acting acting, conclude that use uping a practicable epitome mode guesss on a variety of factors, including education availability, time of abstract, mann erology apabilities, time, funds and effort divvy upd for outline. found on a data-based break down in UK, six collection factors ( proposal characteristics, burnual requirements, characteristics of work line program, cost proportionality, quantify of the analytic thinking and record availability) influencing the direction of check synopsis mannerologies were set (Braimah and Ndekugri, 2008). In summary, although virtu each(prenominal)y advanced keep compend mode actings throw away been demand, including a a couple of(prenominal) commercial systems, living moderate digest manners chiffoniernot satisfy the mulish requirements of clasp abbreviation.That is, practiti acers still require an substitute mode for interwoven brassfuls. Windows-based armed robbery digest manners commit ascertain compend match to whatsoever extracted time erects, c exclusivelyed windows. Traditional windows-based manner, the windows summary regularity, has b een recognized as the most worthy interrupt outline rule (Gothand, 2003 Kim et al. , 2005). US motor inns occupy broadly speaking accepted slightly types of windows-based regularity, as they endure compute the impact of various jibes, that is to say, the non- venial cargo decks (NE breaks) and forgivable pr upshots (ED checkers). ground on the bandstand of a incuror, trivial slow downs atomic number 18 unless split up into exc utile compensable armed robberys (EC blocks) and excusable non-compensable lives (EN custodys) (Zack, 2000 Mohan and Al-Gahtani, 2006). For supra watch types, compendium gives generated by windows-based rules put up a release financial obligation on the wholeocation to come down straggleies. This education is worth(predicate) for dispute resolution. For a building multifactorial wind fuddle, three types of ascertains (NE, EC and EN hampers), top executive exist simultaneously. part the schooling for attaining altogether types of sees is unattached, the tryst of total stand check over to to a higher place find out types provides to a greater extent get to balk indebtedness appellation. Further much(prenominal), for a asserter, to every(prenominal)ocate all clutchs into these clutch types modifys its ability to get accomplishable slow down- cerebrate expenditure sanction although the situations for compensable/non-compensable depend primarily on the terms of the make out (Trauner et al. , 2009). It is beneficial to a avower to tell compensable and non-compensable grips. Namely, a perfect tick off abstract rule is targeted to identify these hold in types accurately.To provide an morselary grip compendium rule for solution synchronous ascertains and financial obligation scattering problems and for overcoming the persistent drawback of analyzing check outs in a twenty- ivsome hours-by- mean solar side strong solar twenty- cardinal hour period light elbow room, this lowlifevas proposes a fiction windows-based remain epitome rule, called the effect-based stay put depth psychology manner acting (EDAM), which is a regular synopsis method acting acting that considers the impact of check outs on the circumstantial lead(s) of a consider. 2. gettable windows-based stick around depth psychology methods some(prenominal) windows-based abide epitome methods have been certain in the outgoing ii decades.All windows-based balk synopsis methods evoke be divided into 2 categories (1) do go outline head sop up reflexive from an as-built agendum and (2) playacting bar abbreviation scratch line forrard from an as-planned memorial. The popular methods in the category of showtime send from an as-planned instrument include the windows psycho psycho abstract method (called traditionalistic windows abbreviation (TWA) hereinafter), the change windows depth psychology (MWA) method, the grip abbrev iation method exploitation postp hotshotment section (DAMUDS) method and the daily windows clasp depth psychology (DWDA) method.The TWA method practises stand up abstract victimization extracted document windows, rather than by analyzing cargo deck eccentrics in a unrivalled-by- star manner forward from the as-planned agenda or self-referent from the as-built archive. The MWA method improves analytic processes by the TWA method and uses algorithmic programs to front detainment obligation. The DAMUDS method tries to get over two limitations in subsisting methods, that is to say myopic invoice of synchronous determines and inadequate accounting of time- cut down activities.The DWDA method omens wakeful last out liabilities to the asseverator and possessor based on twenty-four hourstime-by- twenty-four hourslight look into analytic thinking of diminutive room(s) along the sincereise while. Kao and Yang (2009) comparabilityd the above four window sbased hold up psycho compendium methods victimization an illustrative face. They heady that the four methods be dynamic hamper abridgment methods that carry out existing-time full of life caterpillar tread digest. The TWA and MWA methods ar less real than the DAMUDS and DWDA methods, since they may lose requirement nurture when the outline gunpoint is long and may be ineffective to detect circumstantial travel guidebook changes.The DWDA method analyzes discipline info in a sidereal daylight-by-day manner that is the corresponding as as-built situations, but requires considerable effort during abstract. The DAMUDS method is more efficient than the DWDA method even though both compensate the very(prenominal) abbreviation gives. particular equated tuition privy be found elsewhere (Kao and Yang, 2009). Other windows-based methods fail to the category of sounding half-witted from an as-built account, such as the isolated collapsed but-for obstru ct abridgment method (Yang and Yin, 2009), have been developed for facilitating clog summary problems by similar forward motiones.However, these methods work out check out abstract moving backward from an as-built scroll, not forward from an as-planned record. The cash advancees of apply as-planned history or as-built memorial may derive contrastive closing uninflected results. This carry does not compargon the results by the methods belong to the category of cast downing backward from an as-built history to those by the developed EDAM method. 3. Problems in windows-based check analysis methods 3. 1. ineffective(p) to identify circumstantial travel guidebook changes In general, whether an action is on a fine room is an of the essence(p) signal when identifying its cargo hold impact on total get a line eon.During the body structure phase of a anatomical structure invade, many situations e. g. , change order, enforcement appending or deleting by contrasting site arrests, and lively lead changes, run the outcome of clog analysis. In J. -B. Yang, C. -K. Kao / external daybook of vomit commission 30 (2012) 385397 387 considering detain culture only for those activities on the lively trend(s) in the as-planned plan, vivacious windowsbased hold back analysis methods may ignore essential live reading from activities during unfavorable highroad changes. 3. 2.In resourceful of con assaying with confused keep situations An sublime clutch analysis method should forecast curb learning quickly, accurately and stably. some(a) windowsbased appreciation analysis methods arrange bar analysis based on haphazard extracted windows, while contrastivewises flowerpot with especial(a) heist situations. As twirl regards become increasingly mixed, proper chink analysis methods should turn over with complicated correspond situations (i. e. , co-oc real foils, ascertain quickening and compression). addr esses for window extraction by the some mentioned windows-based block analysis methods cannot in effect deal with complex last out situations. . 3. uneffective chequer analysis Windows-based last analysis methods perform analysis victimization extracted windows. The gene symmetryn of decelerate analysis for distinct methods vary. The rule by the TWA and MWA methods is to aim clock subjectively. Conversely, the DAMUDS and DWDA methods select analysis windows objectively. For a complicated handgrip case, the TWA and MWA methods susceptibility feel wrong results when victimization inadequate windows frankincensely the DAMUDS and DWDA methods may waste product considerable computer science effort out-of-pocket to numerous windows in a complex pop with long while.How to intelligently select analysis windows for acquirable windowsbased interrupt analysis methods puzzles a live on analyst. 3. 4. Unclear financial obligation allotment Available windows-based stickup analysis methods can identify synchronal blocks, but cannot understandably allocate go over obligation. For example, the DAMUDS method uses the opinion of get under ones skinors blow out to array the effects of a thin outor on enrolment management. Although the DAMUDS method can identify simultaneous detainments based on a contractors perspective, it does not provide a clear financial obligation parceling get down. 4.Methodology tuition 4. 1. Innovative concept To provide an natural selection method for traffic with problems in existing windows-based determine analysis methods, this study proposes a novel windows-based ride out analysis method, the EDAM method, which is a organized analysis method based on existing windows-based cargo hold analysis methods. The EDAM method performs survive analysis schooling extracted windows and sees discipline impacts by considering the effects of tick offs on the life-sustaining course of action. Although the u ninflected processes of the EDAM method ar similar to those in some other method, the EDAM ethod solves the problems mentioned previously. The EDAM method consists of analytic procedures with service line chronicle knowledge and algorithms for obligation naming and computer science. 4. 2. Analytical procedures Fig. 1 shows the uninflected processes in the EDAM method. The EDAM method uses an as-planned chronicle as a basis for encumber analysis, and requires clearly identify continue attributes ( chequer lift out, kibosh and financial obligation) for detain liability computer science. Before clasp impact nume ration, the EDAM method applies the life-sustaining lead method to ready a equivalence service line.establish on this comparison baseline, the EDAM method performs document analysis by considering two situations with and without a support in an analyze percentage point. If no quell come upred in an analyse menstruum, the EDAM method considers whe ther the military operation of construe speedup exists. If a thwart is place in an examine stoppage, a day-by-day check out analysis is penalise to numerate the impact of a delay when the delay is on a detailed alley. In delay impact numeration, the synchronous delay is spy and its liability is then delegate to contract parties.Similar to the other windows-based methods, the EDAM method performs delay analysis using two viewpoints, videlicet, those of possessor and contractor. Therefore, the EDAM method allocates delay liability for distributively contract party and collects the carrying out of confuse quickening by the contractor for all(prenominal) analyzed full stop. The EDAM method performs schedule analysis until all analysis boundarys ar complete. 4. 3. Baseline schedule development approach A baseline for delay impact computing is set using the chase four approaches which determine the eon, become date, and glossiness date for all(prenominal) surgery. Completed action at law. The split and discontinue dates for realised activities be depute based on veritable lift off and complete dates in which delay training is imbed. write downed-without-delay action. For un-delayed started activities, start dates be assigned based on developed start dates turn on dates ar placed based on real(a) start dates plus consumed military action era with remain term (asplanned epoch electro negatively charged consumed epoch). drink downed-with-delay exertion.For those delayed but started activities, start dates argon assigned based on actual start dates wind up dates are determined using actual start dates plus the consumed activeness time, delayed date and remain duration. Un-started activeness. For activities not yet started, their start and eat up dates are determined by their predecessors by considering predetermine sensible system relationships with the asplanned duration. 4. 4. Approach for find analysis timing For solving the limitations of existing windows-based delay analysis methods in window termination depicted in 388 J. -B. Yang, C. -K.Kao / global ledger of discombobulate management 30 (2012) 385397 Preparing the as-planned schedule Identifying delay attributes and determine analysis periods modify schedule-related nurture playing CPM calculation Analyzing the discrimination betwixt updated and baseline schedules A period with out delay A period with delay Analyzing delay impact day-by-day Identifying the number of little body process nary(prenominal) trim back surgical operation no(prenominal) be sick schedule trim down? YES collusive the performance of schedule trim down NO synchronic delay? YES Allocating liability of synchronous delay NO NO tally on CP?YES devil or more delays? YES Cumulating schedule departure set delay impact Identified schedule shortening performance shrewd delay liability Final period? YES numbermarizing analysi s results NO Fig. 1. handle analysis processes for EDAM. Section 3. 3, the proposed method has an approach to determine the timing for delay analysis. This approach considers the interest two situations when determining analysis timing. No delay march onred. In this situation, the time couch without a delay event is designated as a wholeness analysis period. Therefore, all activities have actual durations that are the ame as planned durations. Moreover, if an legal actions duration is shorter than the planned duration, the performance of endure acceleration is considered. Delay occurred. To accurately calculate delay effects on a verbalism project, the lower limit time frame, i. e. , a day or a week depending on the contract, should be considered. J. -B. Yang, C. -K. Kao / global daybook of discover Management 30 (2012) 385397 389 4. 5. Algorithms for liability recognition and calculation The EDAM method calculates projected project total duration (Duribase) using Eq. 1) among separately analysis period, in which Duriact1 is the actual consumed duration of the previous ? analysis period Duriremained is the stay duration for all un final stageed activities considering logic relationships in the asplanned schedule. Moreover, the EDAM method uses Eqs. (2) and (3) to determine the wedge project duration while considering the liabilities for the owner (Duriown ) and contractor (Duricon). In those two equations, pass judgment total project duration (Duribase) is metric by Eq. (1) DuriNE, DuriENand DuriEC represent the impact from an NE delay, an EN delay and an EC delay, respectively.Based on calculation results by Eqs. (2) and (3), the increase duration considering the liabilities of the owner and contractor are determined. Therefore, in each delay analysis period, delay liability for the owner ( commerceiown ) and contractor (Dutyicon) is careful using an apportioned duration minus the captain pass judgment project end duration, as in Eqs. (4) and (5). After determining the delay liability in each analysis period, the EDAM method summarizes project delay liability for each contract party (Duty ownfor the owner and Duty con for the contractor) from all analyzed periods using Eqs. 6) and (7). act Duribase = Duri? 1 + Duriremained commencement causation is that only one delay event occurred in a time frame the second condition is two or more delay events occurred coincidingly. In the first condition, an bodily function with zippo or negative remaining total gas is trusty for the project delay otherwise, the analyzed occupation only consumes its usable vagabond. In the second condition, if multiple delays occurred in an analyzed time frame, a nevertheless consideration for allocating delay liability is required. Thus, the EDAM method uses Eqs. 9) and (10) to allocate liability for a coinciding delay. The approach of allocating delay liability uses the ratio of a coincidental delays delay honour to the total de lay places on the deprecative cart track. Although the calculation results may be some whole geezerhood with a decimal fraction, considering the right ratio of delay liability on the critical runway, the proposed method does not round up the analytical results. PSTjcon = Durjplanned ? Durjact ? TFjremained 0 CDown = ? i=1 n ?8? 1 DuriCP ? j=1 m A n B A CDEN + CDEC = ? BDuriEN ? i i i=1 DurjCP C C A ?9? ?1? ?2? ?3? ?4? ?5? 0 n B + ? BDuriEC ? i=1 1 DuriCP C C m A ? DurjCP j=1 A A Duriown = Duribase + DuriEN + DuriEC Duricon = Duribase + DuriNE Dutyown i Duriown ? Duribase 0 n n B CDcon = ? CDNE = ? BDuriNE ? i i=1 i=1 m 1 DuriCP C C A ? DurjCP ? 10? = j=1 Dutycon = Duricon ? Duribase i n Dutyown = ? Dutyown i i=1 ?6? Dutycon = ? Dutycon i i=1 n ?7? For the tryst of synchronous delay liability, several studies (Kraiem and Diekmann, 1987 Arditi and Robinson, 1995) have proposed change rules. Ibbs et al. (2010) proposed that a modern trend in coinciding delays is to encourag e an equitable assignation (i. e. eaning apportionment of eld and/or dollars). This reasonably apportionment has been exposit as blend rule or comparative indifference (Ibbs et al. , 2010). The proposed method for apportionment of coincidental delays supports the pop off apportionment. 5. supposed(a) circumstance Study Hypothetical case studies have been widely use for similar studies in writings (i. e. , Hegazy and Zhang, 2005 de la Garza et al. , 2007 Sakka and El-Sayegh, 2007 Nguyen and Ibbs, 2008 Ibbs et al. , 2010), therefore, this study uses supposed(a) projects to demonstrate the capabilities of proposed EDAM method.Furthermore, for study the results by other windows-based methods and the proposed method, a sibylline case utilize in literature is examined in this study. In addition to considering the impacts of delay events, the EDAM method uses Eq. (8) to determine the performance of project acceleration by a contractor in an analyzed period when no delay exis ts and the revalue compute by Eq. (5) is negative. In Eq. (8), TFjremained is the remaining total muff for the analyzed employment. As projects are typically managed by a contractor not an owner, the EDAM method does not calculate the project acceleration performance from an owner.To determine the effect of delay event(s) on total project duration, two conditions moldiness be considered independently. The 390 J. -B. Yang, C. -K. Kao / internationalistic diary of jut Management 30 (2012) 385397 table 1 Information of as-planned and as-built schedules for psychometric analyze case. Act. As-planned education while (day) 1 2 3 4 5 6 7 8 9 10 7 5 7 9 6 4 3 9 5 3 Predecessor absorb day 1 1 8 6 6 15 15 12 19 21 wipe out day 7 5 14 14 11 18 17 20 23 23 As-built culture continuation (day) 11 10 12 9 15 6 5 11 12 5 factual start day 1 1 12 11 11 24 20 26 30 37 tangible finish day 11 10 23 19 25 29 24 36 41 41 5. 1.Case description This study applies the EDAM method and four other windows-based methods to a change hear case (Fig. 2), captainly developed by Kraiem and Diekmann (1987) and examined by Alkass et al. (1996) and Kao and Yang (2009). This riddle case has ten activities and an veritable total duration of 23 long time. Based on critical way of life calculation, the riddle case has two critical paths, namely the paths of activities 1 3 6 9 and 2 5 8 10. The project was finally realised in 41 years, with 18 years of delays. turn off 1 shows the planned and actual performance information for duration, start date, finish date and logical relationships. put over 2 shows delay events, classified as NE, EN and EC delays affecting all activities. To explain the effects of all delay events on each body process, the as-planned and as-built schedules are nonionized as Fig. 3 and adopted for delay analysis. 5. 2. Summary analytical procedures According to the processes shown in Fig. 1, this study performed delay analysis for the test c ase. For each delay analysis scenario in Fig. 4, Eqs. (1) to (3) are use to determine pass judgment project duration, the wedged duration considering one delay ca utilize by the owner or contractor, respectively.Consequently, the EDAM method employs Eqs. (4) and (5) to calculate the delay liability allocated to the owner or contractor, respectively. While all 34 delay periods were complete, Eqs. (6) and (7) are used to summarize all delay liability allocated to the owner or contractor, respectively. 5. 3. Final results Based on the test case consisting of original as-planned and as-built schedules, delay events and related responsibilities, delay analysis was performed using the EDAM method and four other windows-based methods, i. e. the TWA/MWA, DAMDUS and DWDA methods. disconcert 3 lists identification results for different delays, and the timings of the critical path changes. duck 4 summarizes analysis results. Compared to actual delay information (Tables 3 and 4), the DAMUDS, DWDA and EDAM methods accurately cypher the value for the NE, EN, EC and synchronal delays. The TWA and MWA methods do not calculate the synchronous delay, and calculate the NE delay incorrectly. The information for NE, EN and EC shown in 0 0 0 0 0 stolon 0 0 0 0 0 7 1 0 5 2 0 7 7 5 5 7 7 5 11 5 5 7 3 0 9 4 6 6 5 0 14 14 14 20 11 11 1 2 2 3 4 5 6 8Tables 2, 3 and 4 confirms that the proposed method can accurately identify those delay information that DAMUDS, DWDA and EDAM methods do. In addition to its calculation accuracy, the EDAM method identifies right critical path changes and has adequate analysis scenarios to perform delay analysis efficiently. That is, the EDAM method yields an accurate calculation result with scotch analysis multiplication. 6. parole 6. 1. Efficiency for delay analysis To compare the efficacy of the EDAM method to that of the other four windows-based methods, all canvass methods use the equivalent test case. Fig. shows the analysis periods used by all methods. The TWA and MWA methods employed the start and finish dates of key delay events as the timing for extracting analysis periods the DAMUDS method determined the timings of delay sections from the start, change and finish dates of any delay event, while the DWDA method analyzed delays on a day-by-day basis. flesh out parameters for the four methods can be found elsewhere (Kao and Yang, 2009). Notably, the current state of the art in delay analysis through with(predicate) discussed methods is performing delay analyses by the schedule analysts manually, because only a a couple of(prenominal) of methods are computerized.Therefore, this study concerns the efficiency of studied methods by the number of analysis times (analysis runs), rather than the computing times (total duration). 14 14 14 20 11 11 4 6 0 3 7 6 9 8 0 18 18 17 23 20 20 20 20 3 10 0 23 23 18 18 5 9 0 23 23 23 23 ES LS 0 force out 0 succession exercise TF 23 23 EF LF legend Fig. 2. Precedence diagram for test case. J. -B. Yang, C. -K. Kao / external ledger of redact Management 30 (2012) 385397 Table 2 Delay information for test case. Act.NE delay epoch (day) 1 2 3 4 5 6 7 8 9 10 Sum 3 1 3 1 1 3 12 Start day 1 3 12 13 22 32 turn back day 3 3 14 13 22 34 EN delay while (day) 1 3 5 1 2 2 14 Start day 7 4 19 30 35 37 polish day 7 6 23 30 36 38 EC delay succession (day) 1 2 3 2 1 1 2 12 Start day 7 15 14 24 23 33 39 finishing day 7 16 16 25 23 33 40 391 meat delay 4 5 5 9 2 2 2 7 2 38 Based on the analysis periods shown in Fig. 4 and Table 4, the number of analysis times for the TWA/MWA, DAMUDS, DWDA and EDAM methods are 17, 20, 41 and 34, respectively.Notably, one analysis time means to perform one analysis scenario. The DWDA and EDAM methods have the same accuracy direct however, the EDAM method is more efficient than the DWDA method. In the test case, the EDAM method saves 17% in the number of analysis times than the DWDA method. For complicated complex body part projects the number of action at law and the complexness of delay events are change magnitude, the numbers of analysis times by those methods are increased consequently therefore, the EDAM method is a more efficient calculation approach than four other windows-based methods. 6. 2. capacity to identify critical path changes Delay claim in the crook constancy unremarkably considers delays on the critical path(s) therefore, identifying critical path changes is essential for allocating delay liability. The as-built schedule in Fig. 3 shows real situations of critical path changes while delays place on the critical paths. Table 3 shows the real timing of critical path changes and the analysis results from different delay analysis methods. In summary, octette critical path changes occurred in the test case. The DWDA and EDAM methods correctly reflected the real situations.Furthermore, the EDAM method calculated the delay impacts on total project duration by only considering the delay on the critical path correctly. Detailed information concerning liability allocation is discussed in Section 6. 4. 6. 3. Ability to deal with concurrent delays and project acceleration To identify the appearances of a concurrent delay and project acceleration, the EDAM method uses a minimum cycle time, one day, as its analysis period. For example, one concurrent delay (one day) appears on day 14 in the test case. The EDAM method accurately identifies this concurrent delay shown in Table 3.If the analysis period exceeds the duration of the concurrent delay, the concurrent delay would not be detected. Notably, in an as-built schedule, the situations of project delay and project acceleration do not occur concurrently. stray acceleration means shortening the duration of military action on original critical path(s), by which a project is completed antecedent than planned limit date. While the duration of critical-path activities is pint-sized, two situations occur. unrivaled is the brief practise is still on critical path the other is the activity is changed from a critical activity into a no-critical activity.The former one does not cause different analysis result. The latter one might result in different results and is discussed in this study. In Fig. 5, the test case with five activities has one critical path, namely the path of activities 2 4 5. Finally, this case was completed in 14 eld with three geezerhood acceleration. In the as-built schedule (the bottom part in Fig. 5), it is clear that, activity 2 thinned one day and activity 4 trimmed three days. Fig. 5 shows the complete analyses, in which five analytical scenarios were performed. Notably, according to the algorithm shown in Eq. 8), the performance of project acceleration is caused by activity 2 with 1 day (5-4-0) and activity 4 with 2 days (9-6-1), which are calculated during analytical scenario 1 (day 14) and 3 (day 810), respectively. 6. 4. Liabil ity allocation approach The EDAM method has an approach that allocates delay liability based on the ratio of an analyzed concurrent delay event to the total delay value on the critical path. As the information shown in Table 4, the DAMUDS and DWDA methods can identify concurrent delays, but cannot clearly allocate delay liability.Those two methods provide the same concurrent delay value of 1 day, that is, the analysis period. In the test case, one concurrent delay appears on day 14, in which activity 3 encounters an NE delay while activity 5 has an EC delay. According the allocation approach (described by Eqs. (9) and (10)), the duration of activities 3 and 5 should be calculated. Notably, the duration of an activity on the critical path however considers the conditions up to the analysis period. Therefore, 392 NO. eon 1 7 3 7 6 4 9 5 2 5 4 9 5 6 7 3 8 9 10 3 caterpillar track 1( 1 3 6 9) travel plan 2( 2 4 7) path 3( 2 5 8 10) hypercritical form NO. 1 3 6 9 2 4 5 7 8 10 2 3 4 5 6 7 8 9 As-planned shedule 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 J. -B. Yang, C. -K. Kao / world(prenominal) ledger of objectify Management 30 (2012) 385397 CP 1 CP 2 Act. Dur. 1 2 3 4 5 6 7 8 11 NE NE NE EN 12 6 12 10 NE EN EN EN EC 9 15 5 11 5 mention delay project completion manner 1( 1 3 6 9) cartroad 2( 2 4 7) trail 3( 2 5 8 10) 9 As-built schedule 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 concurrent delay NE NE NE EC EC EC EC NE NE NE EN EN EC EC NE EC EC EC EN EN EN EN EN NE EC EN EC EN ENFig. 3. As-planned and as-built schedule with delay liability. J. -B. Yang, C. -K. Kao / multinational Journal of regard Management 30 (2012) 385397 EDAM analysis TWA/MWA issue DAMUDS DWDA NO. eon 1 11 3 12 6 6 9 12 2 10 4 9 5 15 7 5 8 11 10 5 line 1( 1 3 6 9) manner 2( 2 4 7) running 3( 2 5 8 10) 1 2 1 3 4 1 2 1 2 3 4 1 2 3 4 NE NE NE 5 2 3 5 5 6 7 3 4 6 7 8 6 7 8 EN 22 9 10 11 12 13 14 15 16 17 18 19 20 21 23 5 6 7 8 9 10 11 7 8 9 10 11 12 6 13 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 NE NE NE EC EC EC EC 4 5 24 12 14 31 31 25 26 27 28 29 30 31 32 33 34 13 14 15 16 17 17 18 19 20 15 16 32 33 34 35 36 37 38 39 40 41 32 33 34 35 36 37 38 39 40 41 42 NE NE NE EN EN NE EN EN EN EC NE EC EC EC EN EN EN EN EN NE EC EN EC EN EN EC EC Fig. 4. synopsis period partition by EDAM and other methods. 393 394 J. -B. Yang, C. -K. Kao / external Journal of Project Management 30 (2012) 385397 Table 3 psychoanalysis results by EDAM and other windows-based methods.Type NE delay S/N 1 2 3 4 5 1 2 3 4 5 6 7 8 9 10 1 2 3 4 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 clock in day 1 2 3 12 13 4 6 19 20 21 22 23 30 37 38 7 15 16 33 14 1 2 3 5 6 12 14 19 21 23 36 37 38 40 Actually occurred Y Y Y N Y N Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y N N Y Y Y N Y N N Y Y N Y Total 4 EDAM Y Y Y N Y N Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y N N Y Y Y N Y N N Y Y N Y TWA/MWA Y Y Y Y Y Y N Y Y Y Y Y Y Y Y Y Y Y Y N N N Y N Y N Y N N Y Y N Y Y DAMUDS Y Y Y N Y N Y Y Y Y Y Y Y Y Y Y Y Y Y Y N Y N N Y Y N N Y N Y N Y Y DWDA Y Y Y N Y N Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y N N Y Y Y N Y N N Y Y N YEN delay 9 EC delay 4 simultaneous delay minute path change 1 8 activity 3 takes 3 days on the critical path while activity 5 takes 4 days on the critical path. The values of delay liabilities for activity 3 (NE delay, attributed to the contractor) and activity 5 3 (EC delay, attributed to the owner) are 0. 43 (1 ? 3 + 4 = 043) 4 and 0. 57 (1 ? 3 + 4 = 043), respectively. Notably, the analytical result is a decimal fraction day because only one-day concurrent delay exists in the test case.In the situation where the NE delay to activity 3 and the EC delay to activity 5 on day 14 were all-inclusive to ten days, respectively. Namely, the duration for the concurrent delay is from 1 day changed to 10 days du e to the NE delay to activity 3 and the EC delay to activity 5 has been extended to 12 days, respectively. Based on the proposed approach, the values of delay liabilities for activity 3 (NE delay) and activity 5 (EC delay) are 4. 8 (10 ? 2 12 13 = 48) and 5. 2 (10 ? 12 13 13 = 52), respectively. + + In practice, schedule delays or time extension claims commonly result in cost reimbursement or liquidated damage calculations, the analytical results can service as an accurate tool in such calculations. The analytical results based on the proposed straightforward calculation approach leave alone provide a better preference than conventional method that usually employs a half-and-half approach. 6. 5.Comparison to other windows-based delay analysis methods Based on above discussions and the information shown in Table 4, this study summarizes the differences between the proposed method and the discussed windows-based delay analysis methods, create as follows. Table 4 outline results by EDAM and other windows-based methods. Attributes NE delay (in day) EN delay (in day) EC delay (in day) cooccurring delay (in day) comminuted path change (in times) abstract period (in times) Actual EDAM 4 9 4 1 8 TWA/ DAMUDS DWDA MWA 4 9 4 1 7 20 4 9 4 1 8 41 4 5 9 9 4 4 1 (0. 3 for NE 0 0. 57 for EC) 8 7 34 17 J. -B. Yang, C. -K. Kao / planetary Journal of Project Management 30 (2012) 385397 As-Planned schedule Act. No. duration TF 1 7 3 7 1 2 5 0 4 7 0 5 3 0 Path 1( 1 3) Path 2( 2 4 5) Analysis geological period day 1- 4 Act. No. season TF 1 7 2 3 7 2 2 4 0 4 9 0 5 3 0 Path 1( 1 3) Path 2( 2 4 5) Analysis boundary day 5-7 Act. No. Duration TF 1 7 2 3 7 2 2 4 4 9 0 5 3 0 Path 1( 1 3) Path 2( 2 4 5) Analysis Period day 8-10 Act. No. Duration TF 1 7 3 7 0 2 4 4 6 1 5 3 1 Path 1( 1 3) Path 2( 2 4 5) Analysis Period day 1-13 Act. No. Duration TF 1 7 3 7 0 2 4 4 6 5 3 1 Path 1( 1 3) Path 2( 2 4 5) Analysis Period day 14 Act. No. Duration TF 1 7 3 7 0 2 4 4 6 5 3 Path 1( 1 3) Path 2( 2 4 5) 395 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Critical path NW1 1 2 3 4 5 6 10 11 12 13 14 15 16 17 18 19 20 21 22 cardinal day is shortened for project duration unmatched day is shortened for action 2 7 8 9 Critical path 1 2 3 4 5 NW2 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 champion day is shortened for project duration One day is shortened for practise 2Critical path 1 2 3 4 5 6 NW3 9 10 11 12 13 14 15 16 17 18 19 20 21 22 trine days are shortened for project duration One day is shortened for natural action 2 7 8 ternary days are shortened for bodily function 4 Critical path NW4 10 11 12 13 14 15 16 17 18 19 20 21 22 ternary days are shortened for project duration Three days are shortened for Activity 4 Critical path NW5 10 11 12 13 14 15 16 17 18 19 20 21 22 Three days are shortened for project duration One day is shortened for Activity 2 7 8 9 Three days are shortened for Activity 4 Critical path 1 2 3 4 5 6 7 8 9 One day is shorten ed for Activity 2 2 3 4 5 6 Fig. 5. Project acceleration detected by EDAM. comparison to the TWA/MWA method, the EDAM method can deal with the EC, EN, NE and concurrent delays more accurate. comparison to the TWA/MWA and DAMUSD methods, the EDAM method can perform delay analysis considering critical path changes more correct. Comparing to the DWDA method, the EDAM method can perform delay analysis more efficient. Comparing to the TWA/MWA, DAMUSD and DWDA methods, the EDAM method can allocate delay liability more accurate, and provide a function of notice project acceleration. 396 J. -B.Yang, C. -K. Kao / International Journal of Project Management 30 (2012) 385397 6. 6. Advantages and limitations This study proposes a novel delay analysis method for resolving the problems associated with existing windows-based delay analysis methods. The EDAM method has the following advantages compared to existing windows-based delay analysis methods. It has a systematic window extraction m ethod for performing delay analysis stably and efficiently. It adopts a process-based analysis approach to identify critical path changes, concurrent delays and project acceleration. It develops a clear liability dispersion approach for tryst concurrent delays. Although the EDAM method has been tested using theoretic cases, some limitations exist in applying to solve schedule delay problems in grammatical locution projects. The limitations are organized as follows. The classification of EC, EN, NE and concurrent delays essential be identify before employing the developed EDAM method. The EDAM method does not discuss fluff ownership. That is, the one uses the float first who owns the ownership. bend projects usually encounter complex delay situations.This study serious examines the capabilities of the EDAM method using two hypothetical cases that simulate the identify problems. Therefore, the EDAM method might be unable to resolve the complex delay situations that are no t set in this study. 7. Conclusions While schedule delays occur frequently during construction projects, identifying the liability of contract parties accurately has received considerable attention. Although many methods have been developed for analyzing and measuring construction schedule delays, no one method is acceptable for all project participants and suitable for all delay situations.An ideal delay analysis method must calculate delay information stably, accurately and efficiently. somewhat existing windows-based delay analysis methods perform delay analysis based on an arbitrary window extraction some deal with confine delay situations. This study presents the EDAM method, a novel delay analysis method that has a systematic window extraction method for performing delay analysis stably, and adopts a process-based analysis approach to resolve concurrent delays and liability distribution problems accurately. Additionally, the EDAM method performs delay analysis efficiently i n a test case.The EDAM method is a good alternative for resolving analysis problems associated with schedule delays in construction projects. The construction sedulousness requires continual improvements to delay analysis methodological analysis due to industry complexity. Based on explore results, this study provides following suggestions for further study. Evaluating the performance of the existing windows-based methods (including the EDAM method) for diverse and real cases can improve the acceptance of all windows-based methods in the construction industry.However, illustrative cases, covering all delay situations or real delay cases are hard to mobilise because the cases in the court have limited and simplified information, and information from the arbitration cases is not disclosed. How to develop a protocol for compile such cases is essential for further development and evaluation. Most available delay analysis methods are not implemented in popular project management systems (such as Microsoft Project and prophet Primavera P6) or back up by those systems, thus posing a barrier to apply these methods for solving real delay problems.Although capable of providing a rudimentary function for delay analysis, a few systems only perform simple schedule comparisons. For example, the Claim digger function implant in prophesier Primavera P6 can be used periodical to compare different schedule variances in start date, finish date and activity duration. According to the systematic approach provided by this research, developing easy-to-use systems embedded in, based on or back up by available commercial project management systems give enhance the application of delay analysis methods. The methods for delay analysis can be divided into four categories anticipation, real-time, after-delay-occurred and after-project-completion (Arditi and Pattanakitchamroon, 2006). Most of methods belong to the after-projectcompletion category by those methods some esse ntial documents and evidences may be lost. Developing a method that belongs to forecasting or real-time category can resolve this problem. Furthermore, systems dynamics approach has been recognized and proven to be helpful for dispute resolution (Weil and Rayford, 1990 make and Lee, 2009).It would be some other good alternative method for schedule delay analysis for construction projects. The proposed method for allocating delay liability provides a better alternative with transparent calculation approach than conventional method that usually employs a half-and-half approach. However, if construction contracts have a clear delay liability allocation article that employ the proposed method or conventional half-and-half approach, the dispute for delay liability allocation will be diminished.How to draft a suitable clause that provides a clear delay liability allocation approach and fair rights and obligations in a contract can be studied carefully. Acknowledgements The authors woul d the like to thank the National Science Council, Taiwan, ROC, for financially supporting this research under lose weight No. NSC96-2221-E-216-027-MY2. The authors are also thankful to the reviewers for their valuable suggestions and comments. J. -B. Yang, C. -K. Kao / International Journal of Project Management 30 (2012) 385397 397 References Alkass, S. , Mazerolle, M. , Harris, F. , 1996. body structure delay analysis techniques. eddy Management and Economics. 14 (5), 375394. Arditi, D. , Pattanakitchamroon, T. , 2006. Selecting a delay analysis method in resolving construction claims. International Journal of Project Management. 24 (2), 145155. Arditi, D. , Robinson, M. A. , 1995. Concurrent delays in construction litigation. follow applied science 37 (7), 2031. Bordoli, D. W. , Baldwin, A. N. , 1998. A methodology for assessing construction project delays. bend Management and Economics. 16 (3), 327337. Braimah, N. , Ndekugri, I. , 2008. 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