Question? Leave a message!

Simulation Software

Simulation Software
Dr.MasonHanks Profile Pic
Published Date:23-07-2017
Website URL
Chapter 4 Simulation Software Banks, Carson, Nelson & Nicol Discrete-Event System Simulation„„„„„„„„„ ………… „„ Outline Outline and and Purpose Purpose Discuss the history of simulation software. Discuss features and attributes of simulation software, organized into three categories: General General-purpose purpose p programming rogramming languages languages, Flexible and familiar. Well suited for learning DES principles and techniques e.g., C, C++, and Java. Simulation programming language, TM ® ® e.g., GPSS/H , SIMAN V and SLAM II . Simulation environment Good for building models quickly Provide built-in features (e.g., queue structures) Graphics and animation provided E E.g g.:: Arena Arena, Automod Automod,… 2History History o of f S Simulation imulation Software Software 3…………… „„„ History History o of f S Simulation imulation Software Software 1995 - 60 The Period of Search Search for unifying concepts and the development of reusable routines to facilitate simulation. Mostly conducted in FORTRAN 1961 - 75 The Advent Appearance of the forerunners of simulation programming languages languages (SPLs (SPLs.) ) The first process interaction SPL, GPSS was developed at IBM 1966 - 70 The Formative Period Concepts were reviewed and refined to promote a more consistent representation of each language’s worldview Sources: Nance (1995) and panel discussion at the 1992 Winter Simulation conference (Wilson, 1992). 4……………………… „„„ History History o of f S Simulation imulation Software Software 1971 - 78 The Expansion Period Major Major advances advances in in GPSS GPSS came came from from outside outside IBM IBM GPSS/NORDEN, a pioneering effort that offered an interactive, visual online environment (in Norden Systems.) GASP added support for the activity-scanning worldview and event- scheduling scheduling w worldview orldview (at (at P Purdue.) urdue.) 1979 - 86 The Period of Consolidation and Regeneration Beginnings of PSLs written for, or adapted to, desktop computers and microcomputers. Two Two m major ajor descendants descendants o of f G GASP ASP appeared: appeared: SLAM SLAM II II and and SIMAN SIMAN (provide multiple modeling perspectives and combined modeling capabilities). 1987 – Now The Period of Integrated Environments G Growth th of f SPL SPLs on th the personall computter and d t th he emergence off simulation environments with graphical user interfaces, animation and other visualization tools. Recent advancements have been made in web-based simulation. Sources: Nance (1995) and panel discussion at the 5 1992 Winter Simulation conference (Wilson, 1992).…………… „ Selection Selection of of Simulation Simulation Software Software Advice when evaluating and selecting simulation soft ftware: Consider the accuracy and level of detail obtainable, ease of learning, vendor support, and applicability to your applications. Execution speed is important. Beware of advertising claims and demonstrations. Ask Ask tthe he vendor vendor to to solve solve a a small small v version ersion of of your your problem. problem. 6„„„„„ Selection Selection simulation simulation Software Software Model building feature Runtime environment Animation of lay yout features Output features Vendor supp pport and p product documentation 7„„„„„„„„„„„„„ Model Model building building feature feature Modeling world-view IInputt d datta anallysiis capabilit bility Graphical model building Conditional routing Simulation programming Syntax Input Input flexibility flexibility Modeling conciseness Randomness Si Specialliized d componentts and d ttempllattes User-built objects Interface with general programming language 8„„„„ Runtime Runtime environment environment Execution Speed Model size; number of variables and attributes Interactive debugger Model status and statistics 9„„„„„„„„„„„„ Animation Animation of of layout layout features features Type of animation It Import ddrawiing andd ob bjjectts ffilile Dimension Movement Quality of motion Libraries of common objects Navigation Navigation Views Display step SSl electtb ablle ob bjjectts Hardware requirments 10… „„„„„„ Output Output features features Op ptimization Standardized Report Statistical Statistical A Analysis nalysis Business Graphic File Export Database 11„„„„„„„ Vendor Vendor support support and and product product documentation documentation Training Documentation Help sy ystem Tutorials Supp pport Upgrades, maintenance Track Track report report 12……… „ Selection Selection of of Simulation Simulation Software Software Advice when evaluating and selecting simulation soft ftware: Beware of “checklists” with “yes” and “no” as the entries, e.g. many packages claim to have a conveyor entity, however, implementations have considerable variation and level of fidelity. Determine whether the simulation package and language are sufficiently powerful to avoid having to write logic in any external language. Beware of “no programming required,” unless either the package is a near-perfect fit to your problem domain, or programming is possible with the supplied blocks, nodes, or process-flow diagram. 13………………… „„ An An Example Example Simulation Simulation The checkout counter: a typical single-server queue The simulation will run until 1000 customers have been served. Interarrival times of customers Exp(4.5 min). Service times are ((p appprox.) ) Normal( (3.2 min, 0.6 min) ). When the cashier is busy, a queue forms with no customers turned away. Manual Manual simulation simulation in in Examples Examples 3 3..3 3 and and 3 3..4 4.. Two events: the arrival and departure events (logic illustrated in Figures 3.5 and 3.6.) This example is used to illustrate simulations in Java, GPSS/H and SSF in the following slides. 14Global Global View View     Customer being served   Arriving customer (in server)   Server   Customers are waiting Departing customer System to be served (in queue) 15Event Event-scheduling/time scheduling/time-advance advance algorithm algorithm 16…… „„„„„ Simulation Simulation in in Java Java Java is widely used programming language that has bbd een used exttensiivelly iin siimullattiion. It does not provide any facilities directly aimed at aiding the the simulation simulation analyst. analyst. The runtime library provides a random-number generator. It supports modular construction of large models. Simulation libraries such as SSG alleviate the development burden. Provides Provides access access to to standardized standardized s simulation imulation ffunctionality unctionality and and hide hide low-level scheduling minutiae. 17„„„„„„„„„„„„„ …… „ Simulation Simulation in in Java Java Discrete-event simulation model written in Java contains the following following :: Basic components: System state Entities and attributes Sets Events Activities Delay ys Common components (when organizing model in a modular fashion by using methods): Clock Initialization Initialization m method ethod Min-time event method Event methods Random-variate generators Main program Report generator. 18„ Simulation in in Java: Java: The overall structure of Java simulation simulation is: is: 19„ Single-Server Queue Example : Si Simullati tion iin J Java The overall structure structure of of Java Java simulation structure of the grocery checkout counttl er example: 20