Interaction Of The Developer And The Models example essay topic

As simulation is increasingly applied to more complex applications, exploiting efficiencies in model design and model execution becomes a challenging task. Thus the creation of modeling charts, tools, and diagrams... 18 March 2003 A system is understood to be an entity which maintains its existence through the interaction of its parts. A model is a simplified representation of the real system intended to promote the development of understanding. Whether a model is a good model or not depends on the extent to which it promotes the development of understanding. Since all models are simplifications of reality there is always a trade-off as to what level of detail is included in the model.

If too little detail is included in the model one runs the risk of missing relevant interactions and the resultant model does not promote understanding. If too much detail is included in the model the model may become overly complicated and actually preclude the development of understanding. A simulation generally refers to a computerization of the developed model which is run over time to study the implications of the defined interactions of the parts of the system. Simulations are generally iterative in there development. One develops a model, simulates it, learns from the simulation, revises the model, and continues the iterations until an adequate level of understanding is developed. Modeling and Simulation is a discipline; it is also very much an art form.

One can learn about driving a car from reading a book. To really learn to drive a car one must become actively engaged with a car. Modeling and Simulation follows much the same reality. You can learn much about modeling and simulation from reading books and talking with other people. Skill and talent in developing models and performing simulations is only developed through the building of models and running simulations. It's very much a learn as you go process.

From the interaction of the developer and the models emerges an understanding of what makes sense and what doesn't. After some consideration regarding a meaningful means for putting System, Model, and Simulation in an appropriate perspective I arrived at the following distinction. System: A system exists and operates in time and space. Model: A model is a simplified representation of a system at some particular point in time or space intended to promote understanding of the real system.

Simulation: A simulation is the manipulation of a model in such a way that it operates on time or space to compress it, thus enabling one to perceive the interactions that would not otherwise be apparent because of their separation in time or space. Model Types: Effective IDEFO models help to organize the analysis of a system and to promote good communication between the analyst and the customer. IDEFO is useful in establishing the scope of an analysis, especially for a functional analysis. As a communication tool, IDEFO enhances domain expert involvement and consensus decision-making through simplified graphical devices. As an analysis tool, IDEFO assists the modeler in identifying what functions are performed, what is needed to perform those functions, what the current system does right, and what the current system does wrong.

Thus, IDEFO models are often created as one of the first tasks of a system development effort. Behavior Diagrams define the local behavior of an object class. The aim of this design step is to find out whether there exist dependencies between the actions. For instance, an action may only be executed after another action has occurred or there are states in which specific actions can not be performed. We model the behavior of sequential objects (i. e., instances of object classes) by a state-transition diagram. Corresponding to the birth and death actions there are initial and final states.

Other states have to be identified by a name, possibly such that the name gives some intuition about the meaning of the state. Data Flow Diagramming is a means of representing a system at any level of detail with a graphic network of symbols showing data flows, data stores, data processes, and data sources / destinations. The purpose of data flow diagrams is to provide a semantic bridge between users and systems developers. The diagrams are: o graphical, eliminating thousands of words; o logical representations, modeling WHAT a system does, rather than physical models showing HOW it does it; o hierarchical, showing systems at any level of detail; and o jargon less, allowing user understanding and reviewing. The goal of data flow diagramming is to have a commonly understood model of a system. The diagrams are the basis of structured systems analysis.

Data flow diagrams are supported by other techniques of structured systems analysis such as data structure diagrams, data dictionaries, and procedure-representing techniques such as decision tables, decision trees, and structured English. Data flow diagrams have the objective of avoiding the cost of: o user / developer misunderstanding of a system, resulting in a need to redo systems or in not using the system. o having to start documentation from scratch when the physical system changes since the logical system, WHAT gets done, often remains the same when technology changes. o systems inefficiencies because a system gets "computerized" before it gets "systematized". o being unable to evaluate system project boundaries or degree of automation, resulting in a project of inappropriate scope. Conclusion The field of modeling is a fascinating one. Simulations have played important roles in numerous areas for a long time. Expect to see them combine with intelligent technology to produce exciting applications for the economies and the industries of the future.