Steps in simulation study 1. - Clearly understand problem - Reformulation of the problem 2. - Which questions should be answered? - Is simulation appropriate? - Alternate sys designs,Costs? 3. -complexity - involve Model user 5. Program or SP 6. - Does the program performs, what the model describes? 7. –Is the model accurate representation of real system 8. - Which alternatives should be run? - Which paramters should be varied? - length of initialization period -length of simulation run - No. of replications to be made of each run Program documentation – how does the prog work - Progress documentation –project history - chronology of the work - keep project on course

Chapter 4 Simulation Software

Features needed in Programming most of the DESS models: 1.Generating random numbers. 2.Generating random variates. 3.Advancing the simulated time. 4.Determining next event from the event list and passing the control to appropriate block of code. 5.List operations 6.Collecting o/p statistics and reporting the results 7.Detecting error conditions.

Adv of simulation s/w over General purpose programming languages. 1. Decrease in prog. time and reduction in overall project cost. 2. Their basic modeling constructs are more akin to simulation than general purpose prog lang. 3. Simulation models are easier to modify and maintain 4. Provide better error detection.

Classification of Simulation Softwares: Simulation Languages Simulation Packages General Purpose SP Application Oriented SP

Selection simulation Software General capabilities H/W and S/W considerations Animation of layout features Customer support and product documentation Output reports and plots

General Capabilities 1. Modeling Flexibility: 2. Ease of Use ( & ease of learning): GUI -Modeling constructs neither too primitive nor too macro 3. Hierarchy: combine modeling constructs into a higher level construct. 4. Good debugging Aids: -Follow an entity through model -See the state changes -set attribute values. 5. Fast model execution speed: 6. User-friendly Model “Front-ends” 7.Run-time version of the software. 8. Ability to import and export the data.

9. Ability to invoke external routines 10. Ability to automatically simulate different scenarios that iterate on some model parameter. 11. Simulation package should be easily initialized in a nonempty and idle state. 12. Ability to save state of simulation at the end of the run. 13. Cost.: price + maintenance,upgradation, additional h/w and s/w cost.

II. H/W and S/W Requirements: III. Animation and Dynamic Graphics: Desirable features for animation: -high-resolution icons -library of icons, -smooth movement of icons, -speed up and slow down the animation -zoom in zoom out - import CAD drawings and Clip art -display dynamic graphics and statistics on screen

IV Statistical Capabilities A good random number generator A command for making independent runs of simulation model. o/p performance measures

V. Customer Support and Documentation 1.Training 2.Good technical support 3.Good documentation 4.Free demo disk 5.Free trial 6.Regular updates of s/w.

VI. O/P Reports and Graphics Standard Reports Custom reports Intermediate reports Histogram, bar charts etc. File Export Store results in DB.

Other simulation tools Arena Automod Autostat Extend Flexim Micro Saint Promodel SIMUL8 SMPL