Lecture 1 : Introduction to System Simulation
Hanna Lestari, ST, M.Eng Teknik Industri UDINUS - 2015
Pendekatan Sistem z
z
z
Memusatkan perhatian pada keseluruhan (whole) sistem dan interaksinya. Bersifat komprehensif, holistik, dan lintas disiplin Berawal dari existing design, bagaimana future design?
SIMULASI SISTEM SIMULASI KOMPUTER
Method for understanding, representing, and solving complex interdependent problems using computer model (Nancy Roberts et.al., 1983). Consists of : Basic Concept of System Simulation Developing a Computer Simulation Model Analyzing of Outputs
Definisi : System Simulation Tiruan operasi suatu fasilitas atau proses dunia nyata (Kelton,1991) Teknik experimen dengan model sistem nyata untuk menentukan bagaimana sistem meresponse perubahan struktur, lingkungan, maupun asumsi-asumsi.(Bateman et al, 1997) Tiruan sistem dinamis menggunakan model komputer untuk tujuan evaluasi & perbaikan performansi (Harrel et al, 2003)
PERSONAL COMPUTER
Pemodelan Sistem Model & Manfaat Representasi suatu sistem nyata (situasi nyata): problem situation •Abstraksi •Simplifikasi
•Menggambarkan (to describe) •Menjelaskan (to explain) •Memperkirakan (to estimate), •memproyeksikan (to predict) karakteristik (struktur) dan atau perilaku (fungsi) suatu Performance measure sistem (natural or man made)
Problem Situation
MODEL
IMPLEMENTASI
SIMULASI SISTEM Manfaat z z z z z z z z
Study a complex system Experiments with a new design Predict system response To verify analytic solution To evaluate new policies, procedures, requirements As pedagogical device or training Visualize a plan/scenarios Analyzing financial or economic aspects Tantangan :
interdependency
SIMULASI ÆSKILL Perlu Training !
complex
randomness
Analysis Tools z z z z
z
Simulation Hand calculation Spreadsheet Operation Research ÆPrescriptive : LP, DP ÆDescriptive : Queuing Theory Specific Tool (Computerized)
Simulation Tools Bahasa pemrograman Fortran,Basic dll
Aplikasi sangat luas, skil pemrograman tinggi, energi pemodel terkuras pada program
Bahasa Simulation Siman, GPSS
Satu tingkat di atas bahasa pemrograman, masih banyak tuntutan pemrograman, untuk sistem aantrean dan aplikasi
Simulator
Untuk aplikasi spesifik, mudah digunakan, pemodelan cepat, aplikasi terbatas.
Integrasi bahasa simulasi & simulator
Menawarkan kemudahan sekaligus fleksibilitas aplikasi. (promodel=simulation technology)
Steps To Simulation Study Plan The Study Define system
Concept
Build Model Run Experiment
system
Analyze Output model SIMULASI
Struktur model tergantung pada software simulasi yang digunakan !
System Modeling Steps IDENTIFIKASI MASALAH
KARAKTERISASI SISTEM
FORMULASI MODEL
ANALISIS MODEL
SIMULASI
ESTIMASI PARAMETER & SOLUSI VALIDASI MODEL IMPLEMENTASI
Prinsip Pemodelan Start Simple z z z z
Single server Shop-floor Factory Supply-Chain
Prinsip Pemodelan Start Simple z z z z z z z
Single Objects Æ Multi-objects Single-variables ÆMulti-variables Linear Æ Non-linear Deterministics Æ stochastics Process Æ Management Black box Æ white box Closed Æ Open
Pendekatan z
Event-Oriented z
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Process-Oriented z z
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Contoh: Discrete-Event Simulation (DES) Contoh : Transfer Function Banyak digunakan untuk continuous process
Hybrid : Event-Process Approach z
Sebagian besar software menggabungkan dua pendekatan tersebut
Plan the Study : Simulation Objectives ? z
Analisis kapasitas
z
Throughput rate Product mix
z
Analisis Performansi Throughput rate Cycle times Utilization WIP
z
Optimasi Sistem Objective functions Constraints
Studi komparasi Old design New design
z
Analisis Sensitivitas Pessimistic Most likely Optimistic
z
Visualization
Define System (1) Sistem : Engineering, sosial, politik, biologi, ekonomi?
Ada 3 poin : ¾ Objek ¾ Interaksi ¾ Tujuan/Objective objek & interaksinya Output
Performance
Define System (2) Sistem terdiri dari : Entitas, Aktivitas, Resources & Control
Activity
Entity out
Entity in Resources
Control
sistem Sistem : Discrete vs Continuous
, Sistem : Deterministic Vs Stochastic
Conceptual Model z z z z z z
Algoritma Flow Chart Block Diagram Entity Flow Diagram Causal-Loop Diagram Data flow diagram
PRINSIP SIMULASI : Ambil ESSENSI bukan SUBSTANSI !
Black Box Model
Decision (Controllable)
Performance Measure
Parameter (Uncontrollable)
Consequances variables
Change variables
MODEL Optimization Techniques feedback
Aplikasi Pemodelan Classification
Examples
Business Function Application Discipline Industry Organizational Level Mathemathics Represantation Uncertainty
Finance, Marketing, Cost Accounting, Operations Science, Engineering, Economics Military, Transportation, Telecom, Nonprofit Strategic, Tactical, Operational Linear Equations, Nonlinear Equations Spreedsheet, Custom Software,Paper Deterministics, Probabilistics
Case Study (Murty) No
Case Study
1 2 3 4 5 6 7 8 9 10 11 12
A Weigh Lifting B Alloy Selection C Optimal Production D Rocket Launch E Word Population F River Pollution G Weather Changes H Thermal power Station I Component Reliability J Speed of Aeroplanes K Supermarket Operation L Demand for Soft drinks
Jenis Model Deterministik/Stochastic D S D D D D S D S S S S
Aplikasi Simulasi z z z z z z z z
Queuing analysis Capacity planning Cycle time reduction Staff & Resources planning Bottleneck analysis Quality improvement Cost reduction Supply-chain planning
z z z z z z z z
Inventory control Productivity improvement Layout analysis Line balancing Batch size optimization Production scheduling Resources scheduling Maintenance scheduling
