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Unformatted text preview: Cheek sartins‘téaas ‘ activity is 100% complete. I A. Build Internet components - El. Modify roof 8. floor l FriAHgEé; rrt'ais is"; stagger ' atoms}; 12F}!nsflteiiintitties-_ ' iii.) ,,9:!t5fi9!’t'rromnsass i Whitetailin airapeciataa _ 5 rate Man Gets. r i A Program 3.7 Tracking Project Progress in Microsoft Project As shown in Program 3.7, the Gantt chart immediately reflects this updated information by drawing a thick line within each activity’s bar. The length of this line is proportional to the per— cent of that activity‘s work that has been completed. How do we know if we are on schedule? Notice that there is a vertical line shown on the ‘ Gantt chart corresponding to today’s date. Microsoft Project will automatically mOVe this line to correspond with the current date. If the project is on schedule, we should see all bars to the left of today’s line indicate that they have been completed. For example, Program 3.7 shows that activities A, B, and C are on schedule. In contrast, activities D, E, and F appear to be behind schedule. These activities need to be investigated further to determine the reason for the delay. This type of easy visual information is what makes such software so useful in practice for proj— ect management. Bar indicates Key Terms 87 Activity r: is'behind' schedule, as are. activities D and E. Thisis the i'dicater for today's date (Aug. 12). In addition to reading this section on Microsoft Project, we encourage you to load the soft- ware from the CD-ROM that may be ordered with your text and try these procedures. 3 . I . PERT, CPM, and other scheduling techniques have. proven to be valuable tools in controlling large and complex projects. With these tools, managers understand the status of each activity and know which activities are critical and which have , slack; in addition, they know where crashing makes the most sense. Projects are segmented into discrete activities, and spe— cific resources are identified. This allows project managers to respond aggressively to global competition. Effective project management also allows firms to create products and services Project organization (p. 59) Work breakdown structure (WBS) (p. 60) Gantt charts (p. 61) . Program evaluation and review technique (PERT) ( p. 63) Critical path method (CPM) ( p. 63) Critical path (1:. 63) Forward pass (p. 69) Slack time (p. 72 ) Activity-on—node (AON) (p. 63 } Activity-on—arrow (AOA) (p. 63) Dummy activity (p. 64) Critical path analysis (p. 68} Backward pass ([3. 71) for global markets. As with Microsoft Project illustrated in this chapter, a wide variety of software packages are available to help managers handle network modeling problems. PERT and CPM do not, however, solve all the project scheduling and management problems. Good management practices, clear responsibilities for tasks, and straightforward and timely reporting systems are also needed. It is important to remember that the models we described in this chapter are only tools to help managers make better decisions. Total slack (p. 73) Free slack (p. 73) Optimistic time (p. 74) -Pessimisticti1ne(p. 74) r 7 Most likely time ( p. 74) Crashing (p. 79) 88 Chapter3 ' Project Management _ --- using SoftWere to I Solve ‘Pre-ieet" Management Problems: _ In addition to the Microsoft Project sdftware just illustrated, both Excel and POM for Windows are available to readers of this text as project management tools. _' ' ' Egufing Excel 0M - * - ' - .. - .. . . . . . - Excel Oth a Project Scheduling module. Program 3.8 Uses the data l‘rornthe MiIWaukee Paper Manufacturing examplein this chapterr.-(s_ee-Examples 4 and 5). The PERT/(3PM analysis also handles activities with three time estimates. ' _ _ .. . . . 7.7. , . ._ P' Using POM for Windows . . . ._ _ POM for Window’s Project Scheduling module can also find the expected project completion time for a CPM and PERT network with either one or three time estimates. POM for Windows also performs proj-- ect crashing. For further details refer to AppendiX'IV. ' ‘ ' "1 lelw'aukee Paper 2 ‘1 a iProlent Mangement Precedenms: 5 Enter the task names, times, and the names- of precedences. Be careful that the precedence 1“ names match the task names. > Program 3.8 Excel OM's Use of Milwaukee Paper b gata'anamisassitm' ' - i Gan_ttCi13rt ‘ Manufactunng’s Data 67 tom 7‘ ' Inmedlate Presser i'nercuiumn) A ' from Examples 4 and 5 lime # Predz - B. ‘ 9__;B : ' mic i c . 1.1.20 ' ' 1,2,?E D 13;? a 14er - it)" F 1.5. 7 Early Early is iTask ,Start Flnish Start Finish Slack Tlnle ' ta Nomrilieal Acllvllv 081M}: 1.. H Late start is the late finish (from below)- m‘inus the task time. mm'oaanfipa ._. u; c: p hate finishes depend on the tasks that precede the given task. The late finish is the earliest of the dependencies. Early start is the maximum of the com .utations below. Solved Problem 3.1 construct an AON network based on the. following: Immediate . Activity Predecessor(s) A,-B _ C muow> Solved Problem-3.2 Insert a dummy activity and event to correct the following ADA network: ,i-Salvedt’mhlem .3'.3. 7. Calculate the critical path, project completion time T, andpmjeet variance 0%, based en the following AON network intermation: ' ' Activity. Time Variance es in? LS LF Slack A 2 § '0 2: o 2' o 3' 3’ 0 3 _1 “4. 1 c- ' 2 -% -2' 4 2 -4' 0 n' 4 ' '% _.3 . 7' :4 s 1 E" 4 :3 4 .' s 4 8 0 F 3' § "4 7 10 13 6 "' G_ 5 § 8' 13 s 13' o Solved Problem 3.4 7 ‘ To complete the wing assembly for an experimental aircraft, Jinn Gilberthas laid out the seven major activities involved; These activities have been -'1abeled A through G in the following table, whichals'o flecessors, Determine the expected time and. variance for each activity: _ Immediate "iéuetlvity a: m b Predecessors .- A 1 2 ', 3 - —._ B 2 3 ' 4 — ._ C 4 5 _‘ 6 - A D 8 9 10 - B h E 2 5 ' 8 ‘ C,.D " F 7 4 5 6.. D G; 1 2 3 E '__§hows_v their estimated completion times (in weeks) and immediate pree - 50W?!» - . Since we cannot have. me activities starting and ending at the same node, we add the followingdummy acti obtain the correct ADA network: rotation We conclude that the criticalipath'is 'Start—A—CI-E-Gfind: I Total project time =j T i 2 + 2 + 4+ 5):: . aid .. Janitor!» 7' ' .7 - _ Expected times and variances can be computed using Equations (36) . and.('3-7) presented on page. 7'4 in this chapter. The results are summa- rized in' the following tabiez. ' ' ' ' ' i Dummy activity (0 days) _ (512’ .= E Variances on the critical path =' 3+i+1~+—=——i,5 Solved Problems 89 vity and dummy/event to 219 .66 _6 6w . . . . I' 'Enpected Time. _ ' Activity .(in weeks) ' Variance .B I 3 E- C ‘5 r D V g 7 913 _ 57- .._. 1 . _ . ' = 1 .. G: -2. . 3 90 Chapter3 - ProjectManagement Solved Problem' 3.5 Referring to Solved Problem 3.4, now Jim Gilbert would like to determine the critical path for the entire wing assembly project as . _ well as the expected-completion time for the total project. In addi; Activity ES EF LS LF Slack tion, he would like to determine the earliest and latest start. and fin— ' ' " . . . .. I 2 I 7 hi f - 11 t t . ' 1s _ 111168 01 a ac 1v1 res 0 3 . .. 0 _ 3 A s _C 2 - 7 _-'7 12 '_D "3 12 '3 '12_ E F G W Activity Time Jalottiorb , . ' - The AON network. for Gilbert’s project is shown in Figure 3.18. Note that this project has multiple-activities (A andB) with no . . immediate predecessors, and multiple activities (F and G) with 12 17 ' 14 19 . ' no successors. Hence, in addition to a unique starting activity _ l7 19 . 17 '_ 19 , (Start), we have included a unique finishing activity (End) for the ' . Expected plject length = 19 Weeks protect. '. - ‘ - ' _ Variance of the-critical path '=1_333 Figure 3.18 showa the earliest and latest times for all act1v1t1es. ‘ Star)de deviation of the critical path-$1.155 weeks The results are also stunmarized 1n the followrng table: 12' .17' 12 ' '17 - The activitics'along the critical path are B,_D, E, and G, These activ- > Figure 73.18 Critical 'Path for Solved Problem 3.5 ' Starting Activity Dummy Ending ; Activity :50th Problem _3. 6 _ The following information has been computedlfrom a project: _ The normal curve appearsas follows: Expected total project time = T = 62 Weeks I _ Project variance (5;) = 81 What is the probability that the projectfiwill be completed 18 weeks before its expected completion date? _ Jammie - The desired completion date is 18 weeks before the expected completion date, 62 weeks. The desired completion date is 4-4 (or- 62 — 18) weeks: ' ' . of? = ,l'Project variance _ . Because the normal curve is symmetrical and table values are cal- _ Duo date— Expected completion date culated for positiVe values of Z, the area desired is equal to 1 —— (table ‘ Value); For z ; +2.0, mammal the-table is 97725. Thus, the area corresponding toa Z value of —-2.0 is .02275 (or 1 — 97725). Hence, the probability of completing the preject 18 Weeks before the expected completion date is approximately .023, or 2.3%. Z Active Model Exercise 9 1 Determine the least. cost of roducing the project completion date jam,” . by 3 months based ontho following information: I I r - The first step in this prob lem is to oomthto ES, EF,_ LS, LP, and r slaok fOr :3th activity: . 3 _' " __ '. ' Activit -' ES EF ‘ LS _ _ ' " 0 “_6 9r . . _ . .0 7 -' 0' r 7 '6 13 I 15 - 22 7' ‘ 13 -7 '. 113' 3 1 '22 13 . 22- The critical path consists of activities B. D, and E. .. . . _ ' " Next, crash coso’month must be computed foreach activity; - Normal Crash - - . --- . . - r 7 ~ Tilt-1o Time - -- - N01111:)! CraSh. ‘ Normal eras-h Cost.“ crash ” ‘ (months) . (months) Cost Cost .. Time —_ N 0111131 ' C05” Critical . ' " ' ‘_ ' 7 Activity Crash Time ' " COSt' Month " Path? 6 - "A .' [2 $400 .,: $200/Inonth No -' B' . . 2. 500' ' 250/m0n'th Yes . C " 7 1. . 300 300/month No D . '2 . I . 600 :__ BOO/month _ Yes E - i ' - 200' _ ZOO/month Yes Finally, we will select-th-at-aotivity-on the or-itieal path 'with the: smallest .crash costgi’month. This'is activity-E. Thus, we can reduce the total project oompletion date by 1 month for.‘ an additional cost of $200. We still hood to redone tho-projectoomplotion date? by 2 ' more months. This reduction can be achieved. at leastcost along tho; critical path by reducing activity B by— % months for an additional .;- I t - . r " '_ - I ‘ . r . . cost of $500. This solution is summarized intho'following table: I I Actinity ' .I ' Months Reduced '_ . .Cost- I E '. 1 . . - $200 .- _B- .7 _ -' " 2 ' "500 . I - ' ' ' Total: $700 l 1 two. Model Exercise . _ MilwaukeoPaper Manufacturing._ This Active Model alloWS you'to ovaluaté changes in important . ' 4.. ' - elements 011 the hospital .notwork we saw in_:this chapter, using your CID—ROM. Soc Active; Model-3.1.. !| - ' 'Ganstchart 4 Active Model 3.1 g " - 325:9“ 1; '- Project Management I 7" mutt}. “iii JUL. ...Er.°.°!=.°°.“° a. ' 3.. um": :-t, C' '. {1'13} J A“ 3‘: E) i“ I 9:“; :. 5 . Enos 2911713 1. t 1' F a .1 r a .. : (3' i‘ It “ tiff 5"" ' Prnlacl um: 15 ‘ it t ' F 7 _ __________________ W l 7 IE Chapter 3 - Project Management This graph contains a Gantt chart for the single time estimate Milwaukee Paper project. The critical activities appear in red in both the data table. and the Gantt chart. Noncritical activities appear in green in the Gantt chart, and the right side of these noncritical activities displays the amount of slack they have. You can use the scrollbars to change the times of the individual activities. For critical activities, when you change the times the project times will change. For noncriti'cal activities, if you increase the time, then they will eventually become critical. ' ' -' - ' - Questions 1. Both. A and H are critical activities. Describe the difference between what happens on graph when you increase vs. increasing H. ' ' - . 2. Activity F is not critical. By how many weeks can you increase activity F until it becomes critical? 3. Activity B is not critical. By how many Weeks can you increase 'activityB until it becomes critical? ' What happenswhen 13 becomes critical? : ' ' ‘ - ' 4. What happens when you increase-B by l more Week after it becomes critical? 5. Suppose that building codes change and as result activity B would have to be completed before activity C could be started. How wouldthis affect the project? 3 I ' ' _ _ _ 5 Before taking the selfitest, reform the learning objectives listed at the beginning- of the chapter and the key terms listed or the end of the chapter: . ' 9 Use. the key or the hack of the text to correct your answers. - Rostudy poges shat correspond to any questions you answered - incorrectly or material you feel uncertain- about. _ 1.. With respect toPERT arid CPM,.an Went: - 21) marks the start or completion of a task. h] is a task or subproject that must. be completed. c) is the amount of time. a task may be. delayed. without affectr ing any. other task in the network. . d) is the amount of time a task may be delayed without change ' ing the overall project Completion time. 2. With respect to PERT and .CPM, free slack: ' a) marks the start or completion of a, task. 1)) is a task or subproject that must be completed. (1) is the amount of time a task may be delayed without effect— ing any edict task in. the network. . d) is the amount of time a rash may he delayed without chaos-— ing the overall project completion time. 3. A dummy activity is required. when: a) the network contains two or more activities that have iden— . tical starting and ending events. 13) two or more activities have the same starting events. c) two or more activities how the same ending events. (I). all of the abQVe are true. ‘ _ 4. Critical path analysis is need to determine: a) the earliest activity start time. h) the lateSt activity start time. c) activity slack time. ' d) all of the above. 5. The critical path of a network is the: a), shortest time path through the netwdrk. b) path with the fewest activities. c) path with the most activities. ' d) longest time path through the network. 6. "(1) EF-WES. - a) the project will be delayed by '1 Week. . o) no other activity in the project is affected... . ' d) the expected time Would. be 5% weeks. 10.. - a). ' the. sum of the variances of all activities in the project. Slack time equals: 3). ES «r t. 1)) LS -— ES. c) Zero. If an activity with free- slack time of 2 weeks is delayed. by 1_ Week: ' - . b) the slack time of all activities that follow this activity is reduced by 1 week. d) the probability of completing the projeot on time decreases. I In PERT, if the. pessimistic time was 14 weeks. the optinfistic 1 time was .8 Weeks, and the most likely time was 11 Weeks; a) the variance would he 1 week. b) the variance Would be 11 weeks. .6) the eXpected time would be 6 Weeks. is). there is not enough information. The. crash cost per week: . a.) is the difference in costs divided by the dififcronce in times (crash and normal). 13) is considered to be linear in the range between normal and crash. . - c) needs to be determined so that the smallest cost values on the critical path may be considered for time reduction first. £1) all of the above. I ' PERT analysis. computes the variance of the total project corn— Pletioh time as ; ' . b.) the sum of the variances of all activities on the critical path. c) the sum of the variances of all activities not on the critical. . path. _ - . i g) "the. variance oflthefinal activity of the project. sea} trues": l g 55 first. com-r - 2:. :itical i ' . -. . amt-awh- - - Problems 93 “ ' " Visit our Companion Web site or use your. student CD-ROM/DVD to help With the material in this chapter. . ' On-Our Companion Web site, On Your Student CDnROM a On Your Student DVD _ www.prenhal1.comfl1eiher - Practice'Problems ' 0 Video Clips and Video Cases - Self—Study Quizzes ' -‘ ExcelOM - - Virtual Office Hours arsenal _ - Practice Problems j _ - Excel OM Data Files Problems ' - Virtual. Company Tour ' - Active Model Exercise - Internet Cases - POM for Windows - - PowerPoint Lecture ' . Microsoft Project'(upon request) Discos-si-o-n Questions 1. Give an example of a situation in which project management is needed. 2. Explain the purpose of project organization. 3. What are the three phases involved in the management of a large project? 4. What are some of the questions that can be answered with PERT and CPM? 5. Define work breakdown structure. How is it used? 6. What is the useof Gantt charts in project management? 7. What is the difference between an activity—on-arrow (AOA) network and an activity-on-node (AON) network? Which is pri- marily used in this chapter? . What is the significance of the critical path? 9. What would a project manager have to do to crash an activity? 10. Describe how expected activity times and variances can be computed in a PERT network. 11. Define early start, early finish, late finish, and late start times. W teal Di lemma. Two examples of massively mismanaged projects are TAURUS and the “Big Dig.” The first, formally called the London Stock Exchange Automation Project, cost $575 million before it was finally aban- doned. Although most IT projects have a reputation for cost over- runs, delays, and underperformance, TAURUS set a new standard. But even TAURUS paled next to the biggest, most expensive pub- lic works project in U.S.'history—Boston’s lS-year—long Central Artery/Tunnel Project. Called the Big Dig, this was perhaps the . B 3.1 The work breakdown structure for building a house (levels 1 and 2) is shown below: _ *Note: Pifmeans the problem may be solved with POM for Windows - and/or Excel OM. 12. Students are sometimes confused by the concept of critical path, and want to believe that it is the shortest path through a network. Convincingly explain why this is not so. 13. What are dummy activities? Why are they used in activity-011- arrow (AOA) project networks? 14. What are the three-time estimates used with PERT? 15. Would a project manager ever consider crashing a noncritical activity in a project network? Explain convincingly. 16. How is the variance of the total project computed in PERT? 17. Describe the meaning of slack, and discuss how it can be determined. 13. How can we determine'the probability that a project will be completed by a certain date? What assumptions are made in this computation? 19. Name some of the widely used project management software programs. poorest and most felonious caso of project mismanagement in decades. From a starting $2 billion budget to a final price tag of $15 billion, the Big Dig cost more than the Panama Canal, Hoover Dam, or Interstate 95, the 1,919-mi1e highway between Maine and Florida. Read about one of these two projects (or another of your choice) - and explain why it faced such problems. How and why do project managers allow such massive endeavors to fall into such a state? What do you think are the causes? a) Add two level—3 activities to each of the level-2 activities to pro vide more detail to the WBS. b) Select one of your level-3 activities and add two level-4 activi- ties below it. -- 3.2 Robert Mefford has decided to run for a seat as Congressman from the House of Representative district 34 in California. He views h'i'S' Siifion‘thTampa'i’gn"for’office as a majOr project and wishes to create a work breakdown structure (WBS) to help control the detailed scheduling. So far, he has developed the following pieces of the WBS: : 94 Chapters - Project Management 'Tm"”’mm‘*w’“mwwwm‘rmmmm ' 3.5 Using AOA, diagram the network described below for . Lew] Levelm No' Acnuty - _ _» . - Sarah McComb’s construction project. Calculate its critical path. 1 1'0 Develop pelmcal campmgn How long is the minimum duration of this network? 2 1 . 1 Fund-raising plan 3 l .11 ' - [WWV‘2wmMr-irfmwwm-fiflimwuynmfimq.“m... .nwu ..m,.,y-3.,. awn“. y—m. .me:..._ 7:77? W... 3 L12 _—~———~w———“——*— Tim; .. 3 1.13. _ ' 2. 1.2 Develop a position on major issues 3 1.2.1 _ _ __ 3 1.22 W. _ . _ 3 1.23 W. . .. . la»; 2 1.3 Staffing for campaign . _ i 3 1.31 3 1.32 M. . 7 3 133 ' o - 3.6 Shirley Hopkins is developing a program in leadership 3 L34 training for middleulev'el managers. Shirley has listed a number of 2 1.4 Paperwork compliafice for candidacy activities that must be completed before a training program of this 3 1'41 nature could be conducted. The activities, immediate predecessors, 3 1! 42 ' ' ' ' and times appear in the accompanying table: 2 1.5 Ethical planlissues m: 3 W I I .mmcdiaw Time Activity Predecessol'ls) (days) Help Mr. Mefford by providing details where the blank lines ' '_; " " " ' 2 appear. Are there any other major (level-2) activities to create? If so, B 5 add an ID no. 1.6 and insert them. C _ 1 D B 10 '- I - 3.3 Draw the activity-onmode (AON) project network E A, D 3 i _' ‘ associated with the following activities for Dave Carhart’s consult— F C 6 f ‘ ing company project. How long should it take Dave and his team to G E, F 8 1 complete this project? What are the critical path activities? _ 1 ‘ a) Develop an network for this problem. Activity Predecessofls) (days) b) Whatis the “meal Bath? , , i I W -- -- ' -- - ~ - - - c) What 15 the total project completlon time? - . f]: I d) What is the slack time for each individual activity? 93:! a; i C A 6 l ,4 D B 6 - - 3.7 Task time estimates for a production line setup project .i E B 4 at Robert Klassen’s Ontario factory are as follows: i i F C 4 W G D 6 i'rM-WirrrW'mmr-HE'Ct“aw"?mvar‘»werri'-'symrmrmmww'rfi'mffimflflmfl g H 8 . Immediate 21 TActivity Time (in hours) Predecessors g A 6.0 —H. j ' 3.4 Given the activities whose sequence is described by B 7.2 -- the following table, draw the appropriate activity-on-arrow (AOA) C 5.0 A . network diagram. D 60 B, C _ a) Which activities are on the critical path? E 4.5 B. C j _ b) What is the length of the critical path? P 7-7 r .W G E F .1 Immediate Time MM :1) Draw the project network using AON. _ A . — 5 b) Identify the critical path. ' B A 2 c) What is the expected project length? C A 4 d) Draw a Gantt chart for'the project. 5395 D B 5 E B 5 3 s Th ' ' ' ‘ - ' d F C 5 - - : e City Commissron of Nashvrlle has decrded to butl G E F, a botanical garden and picnic area in the heart of the city for the H 1') recreation of its cidz'ens'TTh'e precedence table for all the activities .1 G H 5 m required to construct this area successfully is given on page 95- Draw the Gantt chart for the whole construction activity. Table for 3.8 Problems 95 .. . . ' 'Innnediate - Code Activity Description _ (in hours) Predecessoflsj _ . A Planning Find location; determine resource requirements 20 None “B3 Putchasing Requisition of lumber and sand ' 60 - ' Planning ; C Excavation Digand grade -. _ '100 ' Planning _; - D Sawing Saw lumber into. appropriate sizes ' 30 Purchasing 1- -E' 7- Placement Position lumber in correct locations 3 , , .' j'. . “20 . _. _ ,...,.Sawing,.excarationw _ 'F_ - Assembly _ Nail lumber together - . . _'10. = . Placement G t - Infill . . Put sandin and under the equipment _ ' 20 - _. Assembly -H Outfiil Put around theequipment ' 10 - . ' Assembly I‘ I ' Decoration ' - he gardenflandsca . 30 ._ ' Infi11,outfill o t 3.9 Refer to the table in Problem 3.8. a) Draw the AON network for the construction activity. b) Draw the ADA network for the construction activity. - 3.10 The activities needed to build an experimental chem- ical contaminant tracking machine at Charlie Cook Corp. are listed in the following table. Construct an AON network for these activities. ‘ may we...” l....-.. _ WWWW“W{ r w - -- -'Immediate Immediate Activity _ Predccmsots) . Predecessor(s) B B . C . (2.1721 n... Dee-mm... “Ewan. - 3.11 Charlie Cook (see Problem 3.10) was able to deter- mine the activity times .for constructing his chemical contaminant tracking machine. Cook would like to determine ES, EF, LS, LF, and slack for "each activity. The total project completion time and the critical path should also be determined. Here are the activity times: . (Witt). ' 4 6 ' 3.12 The activities described by the following table are given for the Duplaga Corporation: ‘ Immediate I Activity ' 'Predecessor(s). Time I A —-‘ 9' B A _ 7 _c A 3 D B 6 B 9 F C 4‘ G 11F 5.. H D 5 WI G,H 3. a) Draw the appropriate AON PERT diagram for Ed Duplaga’s management team. b) Find the critical path. c) What is the project completion time? EX 0 3.13 A small renovation of a Hard Rock Cafe gift shop has six activities (in hours). For the following estimates of a, m, and b, calcu- late the expected time and the standard deviation for each activity: Activity 'e' ' In. .11- A . 11 -. 15 19_ B 27 at ' 41 _'18'--"1s-.'1s _ D. ' s' 13 - 19 E = -'17 1s 2.0: F' 1:6} -- 1:9. '- 22 Ba - o 3.14 McGee Carpet and Trim installs carpet in commercial offices. Andrea McGee has been very concerned with the amount of time it took to complete several recent jobs. Some of her workers are very unreliable. A list of activities and their optimistic comple- tion time, the most likely completion time, and the pessimistic com- pletion time (all in days) for a new contract are given in the follow- ing table: - .. :T‘F’i-e'ti‘w). 1 3 Immediate . Activity a - : jb ' 'Predecessorts) A 3 . .6 :. 8.. . F B _ 2 '4 ' ._4‘- - .~ :C 1 .2 [3 . —— D 6: 77 s c - a 2 _ 4 ti 13,13 is a 10 14 'A,-E G 1 - 2- - .4: A,E H - 3 6 .9 ; F I ._ . 10 .11 .12.. I o J 14 -16, . ‘20: c K __.s ' 10 _ H,1 a) Determine the expected completion time and variance for each activity. 7 b) Determine the total project completion time and the critical path for the project. c) Determine ES; EP;'I:;S, LF, and'sl'ack' for each activity; d) What is the probability that McGee Carpet and Trim will finish the project in 40 days or less? BK 96 Chapter3 ° ProjectManagement - ° 3.15 The following is a table of activities associated with a project at Bill Figg Enterprises, their durations and what activities each must precede: zscram-a:tum:n-i:w.:7izimrsmwr : aumvrmruwvrmme'v .mvm: '“‘:'rr*:ri9F.-4:' . . Activity Duration (weeks) Precc as A (start) ' B, C B E C F E F F (and) . . .. . . — a) Draw an AON diagram of the project, including activity durations. b) Define the critical path, listing all critical activities in chronolog- ical order. 0) What is the project duration (in weeks)? (1) What is the slack (in Weeks) associated with any and all noncrit— ical paths through the project? fig H 3.16 Assume that the activities in Problem 3.15 have the following costs to shorten: A, $300/week; B, $100iweek; C, $200lweek; E, MOO/week; and F, $4OOIWeek. Assume also that you can crash an activity down to 0 Weeks in duration and that every week you can shorten the project is worth $250 to you. What activities would you crash? What is the total crashing cost? - - - 3.17 Bill Fennema, president of Fennema Construction, has developed the tasks, durations, and predecessor relationships in the following table for building new motels. Draw the AON network and answer the questions that follow. ' ' Time Estimates (in weeks) Immediate Mast Activ‘ty Predecessoris) Optimistic Likely Pessimistic A ~--— 4 8 10 B A 2 8 24 ' C A 8 12 16 D. A 4 6 10 E B 1 2 3 F E, C 6 8 20 G E, C 2 3 4 H 2 2 2 I F 6 6 6 J D, G, H .4 6 12 K_ a I, J 2 2 3 a) What is the expected (estimated) time for activity C? b) What is the variance for activity C? c) Based on the calculation of estimated times, what is the criti— cal path? d) What is the estimated time of the critical path? e) What is the activity variance along the critical path? f) What is the probability of completion of the project before week 36? Pat” ' ' ' 3.18 What is the minimum cost of crashing the following project that James Walters manages at Ball State University by 4 days? riflewuewryvmmwmeme-vsweavertfivfiw'meaw5mLm-ymrmmwww-ymrmmwmemmcvxcmfl Normal Crash Time Time Normal Crash Immediate Activity (days) (days) Cost Cost Predecess0r(s) A s 5 s 900 $1,000 m j 13 s 6 300 400 e c j 4 ' 3 500 600 — _ D 5 ' 3 900 1,200 A a s 5 1,000 1.600 M E W - - 3.19 Three activities are candidates for crashing on a project network for a large computer installation (all are, of course, criti- cal). Activity details are in the following table: nfi'r'hWW“v;‘F€HWfiW?fimfi tmt’flflw.‘ :.'e'1"$.m‘“7‘¢‘:‘:=‘.':JL'-‘-V“:mflflflfl'fif T'c‘lfiw“=lwmlflrt#lf‘4 Normal Normal Crash Crash Activity Predccessor Time Cost 'I‘iine Cost A fl. was $6,000 edays $0500 B A 4days 1,200 Zday-s 3,000 . ._ BM, t. its-dart 4299.0 H 9,. a) What action would you take to reduce the critical path by 1 day? b) Assuming no other paths become critical, what action would you take to reduce the critical path one additional day? c) What is the total cost of the 2—day reduction? We” ' ' - 3.20 Development of a new deluxe version of a particular software product is being considered by Ravi Behara’s software house. The activities necessary for the completion of this project are listed in the following table: 1W:m~m:gevmme: areas- ewwaaezms-ramzwsw .e-mmyscmwv-mwmw m-wr'mcm-flmwaw-nfl Normal Crash A I'Time Time Namial Crash Immediate, Activity (weeks) (weeks) Cost Cost Predecessor(s) ' $2,600 f“ .— 2300 —— 500 —- 2,600 f A 1,200 B 4,200 C 2,000 / ‘ D,E a) What is the project completion date? b) What is the total cost required for completing this project on nor— mal time? c) If you wish to reduce the time required to complete this project by 1 week, which activity should be crashed, and how much will this increase the total cost? ‘0 “U7 WTth d) What is the maximum time that can be crashed? How much wouid costs increase? Bid 3.21 The estimated times and immediate predecessors for» the activities in a project at Caesar Douglas’s retinal scanning com" pany are given in the following table. Assume that the activity times are independent. post‘quiv:.~wr;:'v;:!“:y,ww1macaw-awwoommwzmwDmgyzrlanqmmwmwmmm m«me-smaruwm-wmm «rm-MW humediate Time (weigh? a Activity rrcdecessor A ._ B ..— C A D B a) Calculate the expected time and variance for each activity. b) What is the expected completion time of the critical path? What is the expected completion time of the other path in the network? c) What is the variance of the critical path? What is the variance of the other path in the network? d) If the time to complete path A—C is normally distributed, what is the probability that this path will be finished in 22 weeks or less? e) If the time to complete path BHD is normally distributed, what is the probability that this path will be finished in 22. weeks or less? 1") Explain why the probability that the critical path will be finished in 22 weeks or less is not necessarily the probability that the project will be finished in 22 weeks or less. m - M 3.22 Jack Kanet Manufacturing produces custom-built pol— lution control devices for medium-size steel mills. The most recent project undertaken by Jack requires 14 different activities. a) Jack’s managers would like to determine the total project com— pletion time (in days) and those activities that lie along the crit- ical path. The appropriate data are shown in the following table. b) What is the probability of being done in 53 days? 9) What date results in a 99% probability of completion? I Most - - Immediate Optimistic Likely Pessimistic v Activity Predecessofls) Time 'Ifiime _ Tittle, ' A F 4 a. 7 - B H l 2 3 C' A 6 6 6 __D_ A 5 s 11 13 ac 1 9 18 ...;.F‘. D 2 3 6 '_ G D 1 7 a - - H ' E, 4 4 G -_.I -G.H 1 6 S - J I 2 5 7 K I - s 9 11 L J 2 4 6 M K i, 2 3 - N L,M 6 8 10 PX Problems 97 0 - - 3.23 Dream Team Productions, a firm hired to coordinate the release of movie Paycheck (starring Uma Thurman and Ben Affleck), identified 16 activities to be completed before the release of the film. 7. a) How many weeks in advance of the film release should Dream Team haVe started its marketing campaign? What is the critical path? The tasks (in time units of weeks) are as follows: savanna-:21! “watch wmfixmemwwnwh 5:9 W'memamsa xmmwwm . - Most . Immediate Optimistic Like! “Pessimistic - Ac 'vity Predecesmrs Time ' Time Time A' w 1 2 . 4 - B _ a 3.5 .4 C 7— -- 10 -- V12 13 D 'w 4 5- 7 ‘- e ' '2 - 4 5 F .A 6 '- 7. 8 _ B a . 4'. 5.5., H c 5 ..7-.7 9' I c" 9.9 10 .12 :J. ' c _' 2 . 4. - 5-- K. . D - 2- _- 4_ 6 L I“ a . . 2 ' 4. 6 M .5 ' ' 6'. 6:5 - N iii, K. L 1 1.1 2 0 “-i_t._Mf . 5- 7 8._ .P . N W _ s '7_ 9.. m b) If activities and I were not necessary, what impact would this have on the? Critical path and the number of weeks needed to complete theimarketing campaign? P)! '- ' 3.24 Using PERT, I-Ian'ld'Benson was able to determine that the expected project completion time for the construction of a plea- sure yacht is 21" months, and the project variance is 4. a) What is the probability that the project will be completed in 17 months? i. I . b) What is the: probability that the project will be completed in 20 months? 98 Chapter3 - Project Management c) What is the probability that the project will be completed in 23 months? d) What is the probability that the project will he completed in 25 months? e) What is the due date that yields a 95% chance of completion? the o a - 3.25 Bolling Electronics manufactures DVD players for commercial use. W. Blaker Bolling, president of Bolling Electronics, is contemplating producing DVD players for home use. The activities necessary to build an experimental model and related data are given in the following table: rzv‘ifirtmmflmfimc“wmfirv "ti “iv 1%.; rarmwrvrmk‘e'wrw Fir-1:ens-rswsz‘mwmfim'rwrn crwvweemms Normal Crash Time Time Normal Crash Immediate Activity (weeks) (weeks) Cost (:5) Cost ($) Pmdecessor(s) A 3 2 'L000 L600 me E 2 I 2,000 2,700 — C. l i 300 300 —- _ .D_ 7 3 1 ,3 00 l ,600 A E 6 3 850 1,000 B F 2 1 £000 5,000 C G 4 2 1,500 2.000 D, E a) What is the project completion date? b) Crash this project to 10 Weeks at the least cost. c) Crash this project to 7 weeks (which is the maximum it can be crashed) at the least cost. Eli? - - - 3.26 The Maser is a new custom-designed sports car. An analysis of the task of building the Maser reveals the following list of relevant activities, their immediate predecessors, and their durationfi: gum»w,~g~v_w::n_:f- wmfimmwmsur-emmwnw:we“awncmre'emmwewvwrawm—"mmmaw 7mm}? Normal Time (clays) O 8 0-1. Job Immediate Letter Description Predecessofis) Start ' Design Order Special accessories Build frame Build doors Attach axles, wheels, gas tank Build body shell Build transmission and drivetrain Fit doors to body shell G Build engine Bench—test engine Assemble chassis F, Road-test chassis Paint body Install wiring Install interior Accept delivery of special aCcessories Mount body and accessories on chassis Road test car R Attach exterior trim S Finish T‘ 'fl-EHUG'WIP med Dwiwe=>| [Q J—HH mm Lo E 7.! toreOZEi-INHH ozszpaw a u‘i—xHMpi—tMLI—t Us 3 9 5'3 0 Cam -..._-_.____.. .-._._:.‘.’..-.. .m‘n: .c.:.rn'l r...<' 6Source: James A. D. Stoner and Charles Wankel, Management, 3rd ed. (Upper Saddle River, NJ: Prentice Hall): 195. a) Draw a network diagram for the project. in) Mark the critical path and state its length. c) If the Maser had to he completed 2 days earlier, would it help to: i) Buy preassembled transmissions and driven-ants? ii) Install robots to halve engine-building time? iii) Speed delivery of special accessories by 3 days? d) How might resources be borrowed from activities on the noncrit— ical path to speed activities on the critical path? paid” no 3.2.7 You are asked to manage the morning seminars at Miami’s South Beach Wine and Food Festival next year. There are three seminars, each requiring several tasks. You must begin by recruiting a committee of six people to help you. You must also recruit one assistant. This is task A and you expect it will take 12 hours. Then, you will concurrently work on developing ideas for each of the seminars. The business college dean, Bill Quain, says two of the seminars will be on “Dining in South Beach.” You know this won’t take you long. In fact, you plan to divide your committee into two groups to define the topic and then recruit a speaker. You think that these two groups, working concurrently, will take about 4 hours each to complete the task. The third seminar is more difficult. Dean Quain wants some thing on “Great Wines 1 Found in Cheap Restaurants.” You are going to work on this yourself, along wi‘Eh your most trusted assistant. This will be done at the same time as the planning for the other two seminars. It will probably take about 12 hours to complete. All three tasks must be completed before moving on to the next phase. The next phase (task B) will require only you and your assistant. You will write the material for the programs. This will take about 6 hours to complete. For task F, your assistant faxes the program material to four printers, asking them for bids (1 hour). You will use specifications that were developed last year. You receive the bids, make copies, and provide them to the committee members (3 hours). In tasks H and I, the committee again splits up into two groups. Each group reviews all four bids and rates them (4 hours). Then, in task J, the committee members all meet and discuss the bids (2 hours). They then vote on the winning bid. This takes an additional hour. After you and your assistant receive the vote, you both meet with the winning printer (task L), another hour. After the printer returns the proof, you and your assistant are required to have another 1—hour meeting with the printer to give your final approval. ’IWo members of the committee make final arrangements for the venue (5 hours). The printer takes 10 hours to print the programs. Finally, the three seminars are run, concurrently. Each of them takes 2 hours and requires two committee members to be present at each seminar. After it is all over, your entire committee, including you and your assistant, meet for a 1-hour debriefing. a) How long .does the project take? b) Which task has the most slack time? c) Which tasks have no slack time? d) What is the slack time for the critical path? e) How many different tasks are there in this project? i) Calculate how many hours you, your assistant, and the commit- tee spend on this project. g) You value your time, your assistant's time, and the time of your conunittee members at $25/hour. A consultant has bid $5,000 to take over the whole project (excluding the actual printing) and do all the work. Should you accept the bid? Ear ...
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