Title Simulation and Modeling Complete BCA Notes PDF.pdf ✅

www.ckundan.com.np 1 Unit I: Introduction to Modeling and Simulation - Simulation and Modeling System Concept: The term system is derived from the Greek word Systema, which means an organized relationship between functioning units or components. It is aggregation or association of objects joined in some regular manner/interactions or independence. The interaction/independence between the objects causes a change in the system. The system exists because it is designed to achieve one or more objectives. There are more than a hundred definitions of the word system, but most seem to have a common thread that suggests that a system is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective. Fig: A Factory System As shown in the above figure, two major components of the systems are the fabrication department making the parts and the assembly department producing the products. A purchasing department maintains a supply of raw materials and a shipping department dispatches the finished products. A production control department receives orders and assigns work to the other departments. Components of System: 1. Entity: An entity is an object of interest in a system. Example: In the factory system, departments, orders, parts, and products are the entities.
www.ckundan.com.np 2 2. Attribute: An attribute denotes the property of an entity. Example: Quantities for each order, type of part, or several machines in a Department are attributes of the factory system. 3. Activity: Any process causing changes in a system is called an activity. Example: Manufacturing process of the department. 4. State of the System: The state of a system is defined as the collection of variables necessary to describe a system at any time, relative to the objective of study. In other words, the state of the system means a description of all the entities, attributes and activities as they exist at one point in time. 5. Event: An event is defined as an instantaneous occurrence that may change the state of the system. System Entities Attributes Activities Events State Variables Bank Customers Balance, Credit Status Depositing, Withdrawal Arrival, Departure No. of busy tellers, No. of customers waiting Production Machines Speed, Capacity Welding, Stamping Breakdown Status of machine (busy, idle or down) Communication Messages Length, Destination Transmitting Arrival at destination Number waiting to be transmitted Other Examples of System: a. Traffic System b. Telephone System c. Supermarket System d. Transportation Operation System e. Hospital Facilities System and so on.

www.ckundan.com.np 4 System Activities: 1. Endogenous Vs. Exogenous Activity: The term endogenous is used to describe the activity that occurs within the system (activity occurs within an entity of system). And if there is only endogenous activity then the system is said to be a closed system. The term exogenous is used to describe the activity in an environment that affects the system. Hence system, where there is an exogenous activity, is called an open system. 2. Deterministic Vs. Stochastic Activity: If the outcome of the activity/system can be described in terms of the input (in terms of some mathematical function/formulae) then the activity is deterministic activity. When the effect of (outcome) of the activity vary over possible outcomes (can’t be predicted using some mathematical function) then the activity is called stochastic activity. The randomness of the stochastic activity is the part of the system environment because the exact outcome at any time is unknown. However, the random output can be measured and described in a probability distribution. Discrete and Continuous System: 1.Discrete System: Those systems whose state variable changes instantly at separate points in time is a discrete system. Example: Bank System. State variable: Number of customers. Conclusion: Due to these reasons in a bank, the number of customers may arrive only when a new customer arrives or leaves the bank. Here, the changes in the number of customers are in discrete time. Therefore, a bank can be taken as an example of a discrete system. Fig: Discrete System