031.quan ly thoi gian

Qun l d n Cng ngh thng tinThs. Phm Tho

3.1. Qun l thi gian

Mc tiu phn ny:

Hiu Hiu Hiu Hiu

c c c c

tm quan trng ca qun l thi gian cc Quy trnh qun l thi gian cch thc c lng thi gian d n. cc phng php qun l thi gian:

PERT (Program Evaluation and Review Technique) Nhn t hiu lc ton cc (Global Effective Factor GEF) S Gannt CPM (Critical Path Method)

Cch dng phn mm trong qun l thi gian

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Phm Tho

9/27/2011

3.1. Qun l thi gian

Ni dung gm cc phn:

Vn c lng Tm quan trng ca qun l thi gian Cc quy trnh qun l thi gian

Xc nh cc hot ng Sp xp th t cc hot ng c lng thi gian cho mi hot ng

PERT (Program Evaluation and Review Technique) GEF Nhn t hiu lc ton cc (Global Effective Factor) CPM (Critical Path Method)

Pht trin lch biu iu khin lch biu

S dng MP qun l thi gianPhm Tho 9/27/2011

3

3.1.1.c lng

c im ca c lng. Mt s kh khn khi c lng Mt s lu Cc k thut c lng

c lng phi khoa hc S PERT (Xt n phn sau) c lng s dng nhn t hiu lc ton cc (phn sau)

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Phm Tho

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3.1.1.c lng

c im ca c lng.

Sau khi hon thnh Cu trc phn cng cng vic WBS, Qun l d n cn chuyn sang giai on c lng thi gian cn hon thnh cho tng cng vic . c lng thi gian kh hn xy dng bng cng vic c lng thi gian cho mi cng vic nh mc thp nht trong WBS ri t c lng cho tng d n. c lng thi gian s l c s nh gi tin ca qu trnh thc hin d n c lng cng cn xc nh cng vic quan trng, cng vic no phi lm trc cng vic no

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Phm Tho

9/27/2011

3.1.1.c lng

Mt s kh khn khi c lng

6

Thiu thng tin, thiu tri thc Khng lng trc c nhng phc tp k thut Khng lng trc c thun li hay kh khn ca nhn vin khi thc hin d n Sau khi c lng C th c nhiu kn ng gp thay i Sc p ca cp trn Thiu thi gian cn nhc v tnh ton Thiu thi gian gp g trao i vi cc thnh vin, vi khch hang Hn hp v kinh ph Mt s bn tham gia khng cung cp thong tin lin quan (hoc che du) Pht biu ban u khng r rng v mc ch, mc tiu, kt qu. Bng WBS xy dng khng tt.Phm Tho 9/27/2011

3.1.1.c lng

Mt s lu khi c lng

Trc khi c lng, cn xem li WBS xem vit y , r rng, chi tit hay cha? Vi cc cng vic gn ging nhau Cn c lng thi gian tng i ging nhau. Khng bao gi c th c c c lng chnh xc hon ton Vic c lng mang tnh ch quan

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Phm Tho

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3.1.1.c lng

Cc k thut c lng

c lng phi khoa hc S PERT (Xt n phn sau) c lng s dng nhn t hiu lc ton cc (phn sau)

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3.1.2.Tm quan trng ca qun l thi gian

Thi gian trung bnh thc hin d n

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Phm Tho

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Kt thc ng hn

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Kt thc ng hn l mt trong nhng thch thc ln trong qun l d n. Thi gian qu hn trung bnh l 164% nm 1994 gim xung cn 84% nm 2004 Thi gian c linh hot b nht. Cc vn lch biu l l do chnh dn n xung t trong d n, c bit l trong na sau ca d n

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3.1.3.Quy trnh qun l thi gian d n

Qun l thi gian d n gm nhng qui trnh bo m hon tt d n ng hn. Nhng qui trnh ny gm:

Xc nh cc hot ng Sp th t cc hot ng c lng thi gian cho mi hot ng Pht trin lch biu iu khin lch biu

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Phm Tho

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Xc nh cc hot ng

Lch biu d n bt ngun t ti liu khi ng d n

Bn tuyn b d n c cha ngy bt u v kt thc, cng vi thng tin v ngn sch Tuyn b phm vi v WBS gip xc nh cn phi lm nhng g

Xc nh hot ng i hi pht trin WBS chi tit hn cng vi nhng li gii thch hiu c tt c nhng vic cn lm, nhm c c cc c lng ph hp vi thc t

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Phm Tho

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Sp xp th t cc hot ng

Xem xt cc hot ng v xc nh quan h ph thuc Ph thuc bt buc: c hu do bn cht cng vic. Ph thuc xc nh bi nhm d n. Ph thuc lin quan gia cc hot ng bn trong d n v bn ngoi d n Dng Phng php CPM (Critical Path Method) xc nh cc quan h ph thuc.

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c lng thi gian cho mi hot ng

c lng thi gian cho mi hot ng, ty theo hng tip cn s c cc c lng khc nhau. Critical Path Method - CPM: thi gian mi cng vic l thi gian xc nh, cho php thc hin c cng vic . PERT: tnh thi gian mong mun (k vng) ca thi gian thun li (lc quan), thi gian khng thun li (bi quan) v thi gian trung bnh thc hin c cng vic . Lp Bng phn tch CPM (PERT) v xc nh ng ti hn (biu din bng s GANTT) v xc nh thi gian hon thnh c d n.Phm Tho 9/27/2011

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Pht trin lch biu

To c Lch biu ph hp. Kim tra lch biu so vi thc t S dng k hoch phng h bt trc Khng lp k hoch cho mi ngi lm vic 100% kh nng vo mi thi im T chc cc bui hp tin vi cc bn lin quan. Phi r rng, trung thc khi bn v cc vn lin quan n lch biu

iu khin lch biu

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3.1.4.PERT (Program Evaluation and Review Technique)

Cch thc tnh cho mi cng vic

c lng PERT cho bi cng thc:

Trong ,

ET: Thi gian mong i OP: Thi gian thun li (lc quan) nht ML (Most Likely): c lng kh d nht PS: Thi gian khng thun li (bi quan) nht

17

Sau khi tnh xong, c th cn phi iu chnh ET, gi tr iu chnh vo khong 7-10% (C th dng chung cho tt c hoc ring tng cng vic) Gi tr tnh c c th cn phi i ra ngy cng/gi cngPhm Tho 9/27/2011


u im

Nhc im

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V d lp v xc nh.

Bng d thi gian thc hin cc chc nng ca mt d n phn mm nh sau (thi gian tnh bng ngy)Nhim v OP ML PS

Xc nh yu cuPhn tch Thit k Lp trnh Kim th Ci t o to

84 4 16 3 2 3

3015 19 50 10 7 7

4025 24 80 14 10 9

Nghim thuTng19

242

8146Phm Tho

122149/27/2011


V d lp v xc nh (tip)

Tnh ETTnh ETNhim v Xc nh yu cu Phn tch Thit k OP 8 4 4 ML 30 15 19 PS 40 25 24 ET 28.0 14.8 17.3

Lp trnhKim th Ci t

163 2

5010 7

8014 10

49.39.5 6.7

o toNghim thu Tng20

32 42

78 146Phm Tho

912 214

6.77.7 140.0

9/27/2011


V d lp v xc nh (tip)

Tnh ET sau iu chnhTnh ET iu chnhNhim v Xc nh yu cu Phn tch Thit k Lp trnh Kim th Ci t o to Nghim thu Tng ET 28.0 14.8 17.3 49.3 9.5 6.7 6.7 7.7 140.0Phm Tho

% iu chnh 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10

ET iu chnh 30.8 16.3 19.1 54.3 10.5 7.3 7.3 8.4 154.09/27/2011

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3.1.5.Nhn t hiu lc ton cc (Global Effective Factor GEF)

Lit k danh sch cc yu t khim khuyt ca ngun lc d n (%), v d:Yu t Tinh thn thp Mc k nng khng tho ng Thiu quen thuc vi d n T l 15% 5% 10%

Trang b khng thch hpKm c t Tng khim khuyt

5%10% 45%

Tnh tng cc gi tr khim khuyt Tnh GEF = Ly 100-Tng gi tr khim khuyt T gi tr c lng khi lng thi gian ban u hon thnh nhim v chia cho GEF22 Phm Tho 9/27/2011

3.1.5.Nhn t hiu lc ton cc (Global Effective Factor GEF) (tip)

Kt qu

Tnh tng cc gi tr khim khuyt GEF = Ly 100-Tng gi tr khim khuytTheo v d trn GEF = 55% T gi tr c lng khi lng thi gian ban u hon thnh nhim v chia cho GEF

G/s tng thi gian thc hin ban u 154 gi Gi tr mi sau iu chnh c tnh n yu t khim khuyt l 280 gi

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Phm Tho

9/27/2011

3.1.5.Nhn t hiu lc ton cc (Global Effective Factor GEF) (tip)

Kt qu

Tnh tng cc gi tr khim khuyt GEF = Ly 100-Tng gi tr khim khuytTheo v d trn GEF = 55% T gi tr c lng khi lng thi gian ban u hon thnh nhim v chia cho GEF

G/s tng thi gian thc hin ban u 150 gi Gi tr mi sau iu chnh c tnh n yu t khim khuyt l 273 gi

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Phm Tho

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3.1.6.S Gannt

M t

S ny ch ra lc bt u v kt thc ca nhim v Mi nhim v c v nh mt s thanh Trc quan, d hiu

V d

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3.1.7.Phng php CPM (Critical Path Method)

Gii thiu Cc bc Mt s lu khi lp V d tnh ton

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Gii thiu

CPM ra i nm 1957 bi DuPon im thun li: Cung cp s mng cho d n Ch ra thi gian hon thnh d n S mng ca mt d n bao gm cc nt lin h vi nhau bng cc mi tn hoc cc cung. Ta quy c, mi cng vic c m t bi mt mi tn v mi nt biu din mt thi im m cc cng vic bt u hoc kt thc, mi nt c gi l mt s kin.

Mt s mng bao gm cc cng vic v cc s kin.Mi tn ch ra quan h gia cc cng vic, phng v chiu di khng c nghaPhm Tho 9/27/2011

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Gii thiu

V d s mngA

1

2

B

3

C 2 cng vic A v B S kin 1: Bt u cng vic A S kin 2: Kt thc cng vic A v bt u cng vic B S kin 3: Kt thc cng vic B

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Cc bc

Bc 0: Lp s mcBc 1: Lp s mng

Bc 2: Tnh ng ti hnBc 3: Tnh chi ph rt ngn trn mt n v thi gian cho mi cng vic trn mng Bc 4: Chn cng vic trn ng ti hn vi chi ph rt ngn nh nht. Rt ngn ti a cng vic ny.

Bc 5: Kim tra chc chn ng ti hn rt ngn vn l ngti hn.o

Nu ng ti hn vn cn l ng di nht trong mng, ktthc. Tri li, Tm ng ti hn mi sau quay li bc 4Phm Tho 9/27/2011

o29


Mt s lu khi lp

V s mng:

Bt u t cng vic khng ph thuc vo cng vic no c Thm vo ct cc cng vic ch ph thuc vo cng vic th nht Tip theo l cc cng vic ch ph thuc vo cc ct va them vo Tip tc cho ti khi khng cn cng vic no na Quy tc sau c th tng qut li cc trn:

Trc khi mt cng vic bt u, cc cng vic i trc n phi kt thc Mi tn ch ra trnh t gia cc cng vic Mt s mng ch c mt im bt u v kt thc Hai s kin ch c th ni vi nhau bng mt cng vicPhm Tho 9/27/2011

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Mt s lu khi lp

Cng vic gi: C 2 trng hp phi s dng cng vic gi

TH1: Trng hp cc cng vic ph thuc nhau dng sau:Cng vic A B C D

Ph thuc vo A A B,C

Nu khng dung cng vic gi, ta v nh sau:

1

A

B

D

2

C

3

4

Vi phm quy tc 2 s kin ch ni vi nhau bng 1 cng vic Ta cn a vo cng vic giPhm Tho 9/27/2011

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Mt s lu khi lp

TH1(Tip)

Nu s dng cng vic gi, ta v li nh sau:3B X

1

A

2

C

D

4

5

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Phm Tho

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Mt s lu khi lp

Cng vic gi (tip):

TH2: Trng hp cc cng vic ph thuc nhau dng sau:Cng vic Ph thuc vo

DE

-

FG

D,ED

Nu khng dng cng vic gi, ta v nh sau:1D F

4 3E G

233

D

59/27/2011

Phm Tho


Mt s lu khi lp

TH2 (Tip)

Vi phm quy tc 2 s kin ch ni vi nhau bng 1 cng vic Ta cn a vo cng vic gi Nu s dng cng vic gi, ta v li nh sau:

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3.1.7.Phng php CPM Tnh ton

2. Lp bng tnh

Cch lp bng phn tchPHN TCH CPMThi gian ES LS EF LF LS-ES

Hot ng

hon thnhThi gian hon thnh: Trong ES(Earliest Start):Thi gian sm nht mt cng vic c th bt u EF(Earliest Finish):Thi gian sm nht mt cng vic c th kt thc LS(Last Start):Thi gian mun nht mt cng vic c th bt u35

Tng chi ph:

LF(Last Finish):Thi gian mun nhtPhm Tho mt cng vic c th kt thc 9/27/2011


2. Lp bng tnh

Cch lp bng phn tch (Tiep)PHN TCH CPM Hot ng Thi gian hon thnh Tnh EF ES LS EF LF LS-ES

EF = ES + thi gian hon thnhTnh LS

LS = LF - thi gian hon thnhThi gian hon thnh cng trnh: Max {EF tt c cc cng vic} Tng chi ph = Tng tt c cc chi ph ca mi cng vic

Ch :

ES ca cng vic nc 0 bng 0ES ca mt cng vic = max {EF ca mi cng vic trc tip trc}

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LF ca cng vic cui cng = thi gian hon thnh cng trnh Phm Tho 9/27/2011 LF ca mt cng vic trc tip = min {LS cng vic i sau}

Thuc hanh: CPM: Xt d n c 13 cng vic nh sauCng vic A B C D E F G H I J K L M TGBT:Thi gian bnh thng TGRN: Thi gian rt ngn 37 n v tnh Thi gian: Tun TGBT 6 10 10 12 4 2 9 5 8 2 10 3 9 TGRG 4 7 8 11 3 1 6 3 6 1 7 1 6 CPBT 200 500 450 750 150 70 800 170 560 300 720 90 620 CPRN Cng vic trc 210 650 500 780 A,B 160 B 75 C 900 C 200 B,E 600 B,E,C,F 345 B,E,H 750 A,B,D 100 B,E,C,H,I,J 650 C,G CPBT:Chi ph bnh thng CPRN: Chi ph rt ngn Phm Tho Chi ph: Triu ng 9/27/2011


1. Lp s mng

Gii thiu

Phn hoch cc cng vic theo tng MC v xc nh cc cng vic phi lm ngay trc cho mi cng vic. Cc cng vic trong ton b cng trnh c phn hoch theo tng MC theo nguyn tc:

Cc cng vic trong cng MC khng c quan h trc sau vi nhau v c cng vic trc nm mt MC trc Trong mi ct cc cng vic khng c vic trc hp thnh mt MC (c du - )

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a. Xc nh cc MC

Ta c cc MC: Mc N0 l tp hp cc hot ng khng c cng vic trc. Mc N1 l tp hp cc hot ng c cng vic trc l N0 Mc Ni l tp hp cc hot ng c cng vic trc l Ni-1

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N0 N1 N2 N3 N4

= = = = =

{A,B,C} {D,E,F,G} {H,I,K,M} {J} {L}

Phm Tho

9/27/2011

CPM: Xc nh cc MCCng vic Cng vic Cng vic Cng vic Cng vic Cng vic

trcA B C D E F G

trc

trc

trc

trc

A,B B C C

-

-

-

-

HI

B,EB,E,C,F

EE,F

-

-

-

JK

B,E,HA,B,D

EHD

H-

-

-

LM40

B,E,C,H,I,JC,G

E,H,I,JG

H,I,JPhm Tho -

J-

9/27/2011 -


b. Biu din s mng

Chn biu din cng vic l cung. Mi nh biu din mt s kin la ni chm dt mt cng vic trc v bt u mt cng vic tip theo Cc cng vic c xp c xp t tri sang phi, c ghi thi gian thc hin. Nu mt cng vic c hai cng vic trc tip cng mt NC th phi ni hai cng vic bng mt cng vic o, c thi gian thc hin bng 0. V d, D c hai cng vic trc trc tip A, B cng nc nn ni A, B bng mt cng vic o (mi tn chm) t tn C V d I c hai cng vic trc tip trc E,F cng cp t tn GPhm Tho 9/27/2011

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b. Biu din s mng

V s mng

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2. Lp bng tnh

Cch lp bng phn tchPHN TCH CPMThi gian ES LS EF LF LS-ES

Hot ng

hon thnhThi gian hon thnh: Trong ES(Earliest Start):Thi gian sm nht mt cng vic c th bt u EF(Earliest Finish):Thi gian sm nht mt cng vic c th kt thc LS(Last Start):Thi gian mun nht mt cng vic c th bt u43

Tng chi ph:

LF(Last Finish):Thi gian mun nhtPhm Tho mt cng vic c th kt thc 9/27/2011


2. Lp bng tnh

Cch lp bng phn tch (Tip)PHN TCH CPM Hot ng Thi gian hon thnh Tnh EF ES LS EF LF LS-ES

EF = ES + thi gian hon thnhTnh LS

LS = LF - thi gian hon thnhThi gian hon thnh cng trnh: Max {EF tt c cc cng vic} Tng chi ph = Tng tt c cc chi ph ca mi cng vic

Ch :

ES ca cng vic nc 0 bng 0ES ca mt cng vic = max {EF ca mi cng vic trc tip trc}

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LF ca cng vic cui cng = thi gian hon thnh cng trnh Phm Tho 9/27/2011 LF ca mt cng vic trc tip = min {LS cng vic i sau}

031.quan ly thoi gian

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