1. Hierarchical Modeling

2.  Explain the 3 different types of model for which computer graphics is used for.  Differentiate the 2 different types of entity  Identify the 3 categories of model representation.

3.  Modeling: creation & manipulation of a system representation  Model: any single representation, which is graphical or descriptive.  Graphical or Geometric models are component parts of a system with entities such as lines, polygons, circles, etc.

4.  Graphics can be used to create and edit the model, to obtain values for its parameters, and to visualize its behavior and structure.  Among common types of models for which computer graphics is used are: (a) Organization model:  hierarchies representing institutional bureaucracies.  always have various directed-graph representation  such as organization chart.

5. (b) Quantitative models:  equations describing financial, sociological,  and mathematical systems.  often depicted by graphs or statistical plots.  graphical representation is charts, pie chart, line charts. (c) Geometric models:  collections of components with well-defined geometry &, interconnections between components,  including engineering and architectural structures.  always depicted by block diagrams.

6. “A model is a representation of some or all of the parts of a concrete or abstract entity” (a) Concrete Entity: something that physically exist, allow people to visualize and understand the structure and behavior of the entity; also provide a convenient vehicle for experimentation with; and prediction of the effects of inputs or change to the model e.g : cars, buildings, and circuit boards.

7. (b)Abstract Entity :  something that does not physically exist.  e.g : management structure in a company and social group.

8.  Models are cheap than. crashing a vehicles. building a model to test in wind tunnel.  Model are safer than. to really experience the nuclear-reactor plant malfunctions.. actual testing on passenger compartment during crashes.  What are the problems with model?. Incorrect model will not produce accurate or realistic results.. Incorrect inputs will not produce accurate or realistic results. (Garbage in, Garbage out.)

9.  Geometric or graphical model describes components with inherent geometrical properties.  Among the ingredients a geometric model may represent are:  1. Layout and shape of components (i.e., the geometric of the entity), and other attributes affecting the appearance of the components such as color.  2. Connectivity of components (i.e., structure of the entity)  3. Application-specific data values and properties associated with components, such as electrical characteristics.

10. Three-categories of model representation:  1. Data-based. constructed from a set of data stored (in table or linked list). e.g. the points generated by a digitizer from a model car.  2. Procedure-based.. uses algorithms to transform input into predicted output.. e.g. a weather simulations that calculate variations in temperature, pressure and rainfall over time.

11.  3.Mixed.. Useful models are rarely completely data-based or procedure-based..A combination of both is common..Two types: ((a). Data with procedures  Data: wire-frame model of a car produced from points generated from a digitizer.  Procedure: algorithms to calculate how the points and lines would react to a simulated impact.

12. ) (b).Procedures with Data.  Procedures: weather simulation algorithms  Data: the inputs to the simulation are real weather observations. The predicted output of the simulation is compared with the real weather observed to test the model.

13.  Information describing a model is usually provided as a combination of (a). geometric data (b). non-geometric data.

14.  (a). Geometric data  geometric information includes: 1. coordinate positions for locating the component parts 2. output primitives 3. attribute functions to define:  the structure of the parts  data for constructing connections between the parts.

15. (b). Non-geometric data  Non-geometric information includes  1. text labels  2. algorithms describing the operating characteristics of the model  3. rules for determining the relationship or connection.

16.  Models can be organized as hierarchy of symbols.  Symbols used to form a composite objects called modules.  Group of modules will form higher-level modules.  Symbols available in application modeling package are defined and structured according to the type of application the package has been designed

17.  A hierarchical model of a system can be created with structures by nesting the structures into one another to form a tree organization.