METODE SIMULASI Pertemuan 20 Matakuliah : J1186 - Analisis Kuantitatif Bisnis Tahun : 2009/2010 METODE SIMULASI Pertemuan 20

Framework Simulasi Monte Carlo Simulasi dan Persediaan Simulasi dan Masalah Antrian Aplikasi Model Simulasi Pengambilan Keputusan Berdasarkan Model Simulasi Bina Nusantara University

Batasan Simulasi Monte Carlo Apabila suatu persoalan sudah dapat diselesaikan atau dihitung jawabannya secara matematis dengan tuntas, maka hendaknya jangan menggunakan simulasi ini Apabila sebagaian persoalan tersebut dapat diselesaikan secara analitis dengan baik, maka penyelesaiannya lebih baik dilakukan secara terpisah. Sebagian secara analitis dan sebagian lagi simulasi Apabila mungkin dapat digunakan simulasi perbandingan Bina Nusantara University

Contoh Soal Harry’s Auto Tire sells all type of tires, but a apopular radial tire accounts for a large portion of Harrycost ’s overall sales. Recognizig that inventory costs can be quite siginificant with this product, Harry’s wishes to determine a policy for managing this inventory. To see what the demmand would like over a period of time, he wishes to simulate the daily demand for a number of days. Bina Nusantara University

Step – 1 Establishing Probability Distributions To establish a probabilty distribution for tires we assume that historical demand is a good indicator of future outcomes Often, managerial estimates based on judgment and experience are used to create a distribution. The distribution themselves can be either emperical or based on the commonly known normal, binomial, poisson or exponential patterns Bina Nusantara University

Step – 2 Building a Cummulative Probability Distribution for Each Variable Histrical Daily Demand for Radial Tires at Harry’s Auto Tire Demand for Tires Frequensy (days) 10 1 20 2 40 3 60 4 5 30 Total 200 Bina Nusantara University

Probability Demand Demand for Tires Frequensy (days) 10 /200 = 0.05 1 10 /200 = 0.05 1 20 / 200 = 0.10 2 40 / 200 = 0.20 3 60 / 200 = 0.30 4 5 30 / 200 = 0.15 Total 200 Bina Nusantara University

Step – 3 Setting Random Number Intervals Cummulative Probabilties for Radial Tires Daily Demand Probabality Cummulative Probability 0.05 1 0.10 0.15 2 0.20 0.35 3 0.30 0.65 4 0.85 5 1.00 Bina Nusantara University

Step – 4 Generating Random Numbers Daily Demand Probability Cummulative Probabilty Internal of Reandom Numbers 0.05 01 to 05 1 0.10 0.15 06 to 15 2 0.20 0.35 16 to 35 3 0.30 0.65 36 to 65 4 0.85 66 to 85 5 1.00 86 to 00 Assignment of random number interval for Harry’s Auto Tire Bina Nusantara University

Step – 5 Simulating the Experiment Bina Nusantara University

Simulated Daily Demand Day Random Number Simulated Daily Demand 1 52 3 2 37 82 4 69 5 98 6 96 7 33 8 50 9 88 10 90 39 = total 10 day demand 3.9 average daily demand Bina Nusantara University

Expected Daily Demand Σ Expected Daily Demand = = (Probability of i tires)x(demand of I tires) = (0.05) (0) + (0.10) (1) + (0.20) (2) + (0.30) (3) + (0.20) (4) + (0.15) (5) = 2.95 Tires 5 Σ i = 0 Bina Nusantara University