System Analysis System Analysis - Mr. Ahmad Al-Ghoul System Analysis and Design

Avicenna System Analysis and Design System Analysis2 Learning Objectives Use decision trees to analyze and describe processes Use decision trees to analyze and describe processes Choose appropriate process specification Analysis Technique Choose appropriate process specification Analysis Technique Describe the relationship between logical and physical models Describe the relationship between logical and physical models

Avicenna System Analysis and Design System Analysis3 Process Description Tools Decision Trees Decision Trees Decision Trees Decision Trees Graphical representation of the conditions, actions, and rules found in a decision table Graphical representation of the conditions, actions, and rules found in a decision table Whether to use a decision table or tree often is a matter of personal preference Whether to use a decision table or tree often is a matter of personal preference Employ tree structures which show conditions and actions within a problem Employ tree structures which show conditions and actions within a problem Decision Tree is read from left to right Decision Tree is read from left to right Root of tree -> name of process Root of tree -> name of process branches -> conditions branches -> conditions Leaves -> actions to be performed Leaves -> actions to be performed

Avicenna System Analysis and Design System Analysis4 Process Description Tools Drawing Decision Trees Drawing Decision Trees First, identify all conditions and actions and their order and timing (if they are critical). First, identify all conditions and actions and their order and timing (if they are critical). Second, begin building the tree from left to right while making sure you are complete in listing all possible alternatives before moving over to the right. Second, begin building the tree from left to right while making sure you are complete in listing all possible alternatives before moving over to the right.

Avicenna System Analysis and Design System Analysis5 Process Description Tools [1] This decision tree is based on the sales promotion policy described above $ This decision tree is based on the sales promotion policy described above $

Avicenna System Analysis and Design System Analysis6 Process Description Tools Decision Tree Advantages Decision Tree Advantages The order of checking conditions and executing actions is immediately noticeable. The order of checking conditions and executing actions is immediately noticeable. Conditions and actions of decision trees are found on some branches but not on others. Those conditions and actions that are critical are connected directly to other conditions and actions, whereas those conditions that do not matter are absent Conditions and actions of decision trees are found on some branches but not on others. Those conditions and actions that are critical are connected directly to other conditions and actions, whereas those conditions that do not matter are absent Compared to decision tables, decision trees are more readily understood by others in the organization. Compared to decision tables, decision trees are more readily understood by others in the organization.

Avicenna System Analysis and Design System Analysis7 Selecting a process specification Analysis Technique Use these guidelines: Use these guidelines: Use structured English when there are many repetitious actions or when communication to end users is important Use structured English when there are many repetitious actions or when communication to end users is important Use decision tables when complex combination of conditions, actions, and rules are found or you require a method that effectively avoids impossible situations, redundancies, and contradictions Use decision tables when complex combination of conditions, actions, and rules are found or you require a method that effectively avoids impossible situations, redundancies, and contradictions

Avicenna System Analysis and Design System Analysis8 Selecting a process specification Analysis Technique Use decision trees when the sequence of conditions and actions is critical or when not every condition is relevant to every action (the branches are different) Use decision trees when the sequence of conditions and actions is critical or when not every condition is relevant to every action (the branches are different)

Avicenna System Analysis and Design System Analysis9 Logical Versus Physical Models Sequence of Models Sequence of Models Many systems analysts create a physical model of the current system and then develop a logical model of the current system before tackling a logical model of the new system Many systems analysts create a physical model of the current system and then develop a logical model of the current system before tackling a logical model of the new system Performing that extra step allows them to understand the current system better Performing that extra step allows them to understand the current system better

Avicenna System Analysis and Design System Analysis10 Logical Versus Physical Models Four-Model Approach Four-Model Approach Four-Model Approach Four-Model Approach Develop a physical model of the current system, a logical model of the current system, a logical model of the new system, and a physical model of the new system Develop a physical model of the current system, a logical model of the current system, a logical model of the new system, and a physical model of the new system The only disadvantage of the four-model approach is the added time and cost The only disadvantage of the four-model approach is the added time and cost

Avicenna System Analysis and Design System Analysis11 Sequence Summary Decision trees consisting of nodes and branches Decision trees consisting of nodes and branches Decision trees are appropriate when actions must be accomplished on a certain sequence Decision trees are appropriate when actions must be accomplished on a certain sequence There is no requirement that the tree be symmetrical, so only those conditions and actions that are critical to the decisions at hand are found on a particular branch There is no requirement that the tree be symmetrical, so only those conditions and actions that are critical to the decisions at hand are found on a particular branch Structured analysis tools can be used to develop a logical model during one systems analysis phase, and a physical model during the systems design phase Structured analysis tools can be used to develop a logical model during one systems analysis phase, and a physical model during the systems design phase

Avicenna System Analysis and Design System Analysis12 Sequence Summary In this Sequence we have In this Sequence we have Defined and explained decision trees Defined and explained decision trees Explained where to use decision trees Explained where to use decision trees Explained how to draw decision trees Explained how to draw decision trees Described the advantages of decision trees Described the advantages of decision trees Explained the guidelines to select a process specification analysis technique Explained the guidelines to select a process specification analysis technique explained the relationship between logical and physical models explained the relationship between logical and physical models

Avicenna System Analysis and Design System Analysis13 Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt, Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt, Publisher: SHELLY CASHMAN SEWIES. Publisher: SHELLY CASHMAN SEWIES. [2] system analysis and design, sixth edition Authors: Kenneth E. Kendall and Julie E. Kendall Authors: Kenneth E. Kendall and Julie E. Kendall Publisher: Prentice Hall Publisher: Prentice Hall [3] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer, Joey F. George, Joseph S. Valacich Authors: Jeffrey A. Hoffer, Joey F. George, Joseph S. Valacich Publisher: prentice hall Publisher: prentice hall [4] System Analysis and Design, 3 rd Edition Authors: Dennis, Wixom, & Roth Authors: Dennis, Wixom, & Roth Publisher: John Wiley & sons Publisher: John Wiley & sons