Lecture 1 :Introduction to System Simulation

Hanna Lestari, ST, M.Eng

Teknik Industri UDINUS - 2015

Pendekatan SistemMemusatkan perhatian pada keseluruhan (whole) sistem dan interaksinya. Bersifat komprehensif, holistik, dan lintas disiplinBerawal dari existing design, bagaimanafuture design?

SIMULASI SISTEMSIMULASI KOMPUTER

Method for understanding, representing, and solving complex interdependent problems using computer model (Nancy Roberts et.al., 1983).Consists of :

Basic Concept of System SimulationDeveloping a Computer Simulation ModelAnalyzing 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 SistemModel & Manfaat

Problem Situation

MODEL

IMPLEMENTASI

Performance measure

•Menggambarkan (to describe)•Menjelaskan (to explain)•Memperkirakan (to estimate), •memproyeksikan (to predict)

karakteristik (struktur) dan atau perilaku (fungsi) suatu sistem (natural or man made)

Representasi suatu sistem nyata (situasi nyata): problem situation•Abstraksi•Simplifikasi

SIMULASI SISTEMManfaat

Study a complex systemExperiments with a new designPredict system responseTo verify analytic solutionTo evaluate new policies, procedures, requirementsAs pedagogical device or trainingVisualize a plan/scenariosAnalyzing financial or economic aspects

interdependency

randomness

complex

SIMULASI SKILL

Perlu Training !

Tantangan :

Analysis Tools

SimulationHand calculationSpreadsheetOperation Research

Prescriptive : LP, DPDescriptive : Queuing Theory

Specific Tool (Computerized)

Simulation Tools

Bahasa pemrogramanFortran,Basic dll

Aplikasi sangat luas, skilpemrograman tinggi, energi pemodelterkuras pada program

Bahasa SimulationSiman, 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 sekaligusfleksibilitas aplikasi.(promodel=simulation technology)

Steps To Simulation Study

system

model

Concept

Plan The Study

Define system

Build Model

Run Experiment

Analyze Output

Struktur model tergantung pada software simulasi yang digunakan !

SIMULASI

IDENTIFIKASI MASALAH

KARAKTERISASI SISTEM

FORMULASI MODEL

ANALISIS MODEL

ESTIMASI PARAMETER & SOLUSI

IMPLEMENTASI

SIMULASI

VALIDASI MODEL

System Modeling Steps

Prinsip PemodelanStart Simple

Single server Shop-floorFactorySupply-Chain

Prinsip PemodelanStart Simple

Single Objects Multi-objectsSingle-variables Multi-variablesLinear Non-linearDeterministics stochasticsProcess ManagementBlack box white boxClosed Open

Pendekatan

Event-OrientedContoh: Discrete-Event Simulation (DES)

Process-OrientedContoh : Transfer FunctionBanyak digunakan untuk continuous process

Hybrid : Event-Process ApproachSebagian besar software menggabungkan dua pendekatan tersebut

Plan the Study :Simulation Objectives ?

Analisis kapasitas Throughput rateProduct mix

Analisis Performansi Throughput rateCycle timesUtilizationWIP

Optimasi SistemObjective functionsConstraints

Studi komparasiOld designNew design

Analisis SensitivitasPessimisticMost likelyOptimistic

Visualization

Define System (1)

Ada 3 poin :

Objek

Interaksi

Tujuan/Objectiveobjek & interaksinya

Output Performance

Sistem : Engineering, sosial, politik, biologi, ekonomi?

Define System (2)

Entity inControlResources

Activity

Entity out

sistem

Sistem terdiri dari : Entitas, Aktivitas, Resources & Control

Sistem : Discrete vs Continuous , Sistem : Deterministic Vs Stochastic

Conceptual ModelAlgoritmaFlow ChartBlock DiagramEntity Flow DiagramCausal-Loop DiagramData flow diagram

PRINSIP SIMULASI :

Ambil ESSENSI bukan SUBSTANSI !

Black Box Model

MODEL

Decision (Controllable)

Parameter (Uncontrollable)

Performance Measure

Consequancesvariables

Optimization Techniques

Change variables

feedback

Aplikasi PemodelanClassification Examples

Business FunctionApplication DisciplineIndustryOrganizational LevelMathemathicsRepresantationUncertainty

Finance, Marketing, Cost Accounting, OperationsScience, Engineering, EconomicsMilitary, Transportation, Telecom, NonprofitStrategic, Tactical, OperationalLinear Equations, Nonlinear EquationsSpreedsheet, Custom Software,PaperDeterministics, Probabilistics

Case Study (Murty)No Case Study Jenis Model

Deterministik/Stochastic123456789101112

A Weigh LiftingB Alloy SelectionC Optimal ProductionD Rocket LaunchE Word PopulationF River PollutionG Weather ChangesH Thermal power StationI Component ReliabilityJ Speed of AeroplanesK Supermarket OperationL Demand for Soft drinks

DSDDDDSDSSSS

Aplikasi SimulasiQueuing analysisCapacity planningCycle time reductionStaff & Resources planningBottleneck analysisQuality improvementCost reductionSupply-chain planning

Inventory controlProductivity improvementLayout analysisLine balancingBatch size optimizationProduction schedulingResources schedulingMaintenance scheduling