1. INTRODUCTION COMPUTATIONAL MODELS

2. 2 What is Computer Science Sciences deal with building and studying models of real world objects /systems. What is a model? A partial description of the components and the properties of a given object/system.

3. 3 Street map - a model of a city graph - a model of the map

4. 4 Computational models Computer science deals with computational models Computational model: given the description of some properties we can compute other properties. Example: Given the graph representation of a map, we can compute driving directions.

5. 5 Implementation of computational models Description of the object Description of the computational process the computer program A device that will perform the process on the object's description - the computer Programming languages: languages used to build computational descriptions of properties and processes

6. 6 Program components Description of the object Properties, memory locations, variables. Variable declaration: data types Declaration part of a program

7. 7 Program components Description of the process A computational process manipulates data. Each manipulation is presented in a program as an executable statement. Executable part : The collection of all such statements

8. 8 Program views Declaration / execution: what the computer does Functions - what tasks are performed and how they are related – structure charts, UML Program control flow: how the operations are sequenced – flowcharts

9. 9 EXAMPLE Vending Machine Processes Process customer input Perform expected output actions Calculate deposited money Refuse service Identify product Dispense product Calculate and dispense change if needed not enough $ is deposited product not available

10. 10 Studying computer science CmSc 150 - Basics and a programming language CmSc 155 - Methods to describe objects CmSc 250 - Methods to design computational processes (algorithms) CmSc 180 - Properties of models CmSc 315 - Properties of programming languages Supporting environments: CmSc 265 - Computer organization CmSc 330 - Digital systems CmSc 335 - Operating systems CmSc 340 - Networks

11. 11 Studying computer science CmSc 360 - How to design efficient algorithms CmSc 365 - The limits: What is computable CmSc 300, 375 - How to put it all together CmSc 370 - Computer Security CIS 260 - Various programming languages Applications: CIS 255, 355 - Databases CIS 270 -Web Development CmSc 310 - Artificial Intelligence