PERENCANAAN & PENGENDALIAN PRODUKSI TIN 4113

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1 PERENCANAAN & PENGENDALIAN PRODUKSI TIN 4113

2 Peremua 3 Oule: Meode Peramala: Expoeal Smoohg (Sgle) Double Expoeal Smoohg Wer s Mehod for Seasoal Problems Error Forecas MAD, MSE, MAPE, MFE aau Bas Referes: Elsayed, A. Elsayed. Aalss ad Corol of Produco Sysem, Prece Hall Ieraoal, Terse, Rchard J., Prcples of Iveory ad Maerals Maageme, Prece-Hall, Pujawa, Demad Forecasg Lecure Noe, IE-ITS, 2011.

3 Expoeal Smoohg New Forecas = α (curre observao of demad) + (1-α) (las forecas) Or F = α(d -1 ) + (1-α)F -1 Ad F -1 = α(d -2 ) + (1-α)F -2, ds Sehgga pada model, semua daa hsors erwakl pada forecas erakhr dega bobo yag semak kecl (uuk daa yag semak lama)

4 Expoeal Smoohg Iclude all pas observaos Wegh rece observaos much more heavly ha very old observaos: wegh Decreasg wegh gve o older observaos 0 1 ( 1 ) ( 1 ) ( 1 ) 2 3 oday

5 Expoeal Smoohg Noes: Oly 2 values (D ad F -1 ) are requred, compared wh for movg average Parameer deermed emprcally (whaever works bes) Rule of humb: < 0.5 = 0.1 o = 0.3 Forecas for k perods o fuure s: F k F

6 Persamaa MA da ES Sama-sama megasumska demad bersfa saoary Keduaya ergaug pada 1 la parameer, N pada MA da α pada ES. Kalau ada red, kedua-duaya erlamba dalam merespo Keduaya aka meghaslka dsrbus error yag sama apabla α = 2 / (N+1)

7 Perbedaa MA da ES MA megakomodaska lebh bayak daa ES haya meympa dua daa: forecas erakhr da acual demad erakhr, sedag MA meympa N daa demad erakhr

8 Double Expoeal Smoohg Wha happes whe here s a defe red? A redy clohg bouque has had he followg sales over he pas 6 mohs: Demad Acual Forecas Moh

9 Double Expoeal Smoohg Ideas behd smoohg wh red: ``De-red'' me-seres by separag seres from red effecs Smooh seres usual maer usg Smooh red forecass usual maer usg Smooh he seres forecas S S D ( 1)( S 1 T 1) Smooh he red forecas T T ( S S 1 ) (1 ) T 1 Forecas k perods o fuure F +k wh base ad red F k S kt

10 Laha Soal (a = 0,1; b = 0,1; X1 = 40; T1 = 0) Perode Demad Level Tred Forecas

11 Expoeal Smoohg w/ Tred ad Seasoaly Apabla ka memlk daa yag megadug pola red maupu seasoaly, ka megguaka model. Prspya, daa ddekomposs mejad 3 baga: Daa dasar Kompoe red Ideks musma Masg-masg kemuda dforecas ersedr dega expoeal smoohg, kemuda dgabug kembal

12 Expoeal Smoohg w/ Tred ad Seasoaly Smooh he seres forecas S D S (1 )(S 1 T 1) C m Smooh he red forecas T T (S S 1 ) (1 ) T 1 Smooh he seasoaly forecas C C D S (1 ) C m

13 Expoeal Smoohg w/ Tred ad Seasoaly Forecas F wh red ad seasoaly F k (S 1 kt 1 ) C km

14 Forecas Errors e = F -p, -D Measures of forecas errors: 100% / ) (1/ ) (1/ ) (1/ x D e MAPE e MSE e MAD

15 Mea Forecas Error (MFE or Bas) MFE 1 1 ( D F ) Wa MFE o be as close o zero as possble -- mmum bas A large posve (egave) MFE meas ha he forecas s udershoog (overshoog) he acual observaos Noe ha zero MFE does o mply ha forecass are perfec (o error) -- oly ha mea s o arge Also called forecas BIAS

16 Trackg Sgals Trackg Sgal. Guaya adalah memoor apakah forecas ka bas (cederug ak / uru secara kosse) 1 1 (Acual demad- - Forecas demad) MAD Aleraf laya, guaka MFE (lebh mudah).

17 Forecas Mejad Lebh Peg Jka Barag harus ada dulu sebelum pelagga membuuhka (producg he produc before here s a defe demad) I adalah kosep saga medasar dar MTS Perusahaa yag memproduks barag aas dasar MTO dak erlalu ergaug pada ramala Lead me pegadaa / produks pajag (lebh pajag dar waku uggu pelagga) Idusr mobl bsa memperpedek lead me sampa yag bsa doleras oleh pelagga dega megubah ssemya mejad assembly o order (ATO)

18 Peremua 4 - Persapa Tugas Baca: Ssem Persedaa Meode Q Meode P

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