August 13, 2015 1 August 13, 2015August 13, 2015August 13, 2015 Azusa, CA Sheldon X. Liang Ph. D. Software Engineering in CS at APU Azusa Pacific University,

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April 19, 2023April 19, 2023 Azusa, CAAzusa, CA

Sheldon X. Liang Ph. D.

Software Engineering Software Engineering in CS in CS at at APUAPU

Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/

CS 470 Software Engineering ICS 470 Software Engineering I

http://www.apu.edu/clas/computerscience/

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CS 470 (SE)CS 470 (SE)22


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(SE)(SE)22: System Engineering vs Software Engineering: System Engineering vs Software Engineering

What is a system What is systems engineering What is systems engineering process What we learn from systems engineering

Break down: Problem Definition (PRD)

Model&Interface: Problem Design (SDD)

Unit coding: Programming (SPP)

Put-together: Integration (SIP)

What we are going to do with DFD


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What is a systemComponents - A purposeful collection of inter-related components working together to achieve some common objective.

External Entities - A system may include software, mechanical, electrical and electronic hardware and be operated by people.

External Dependencies - System components are dependent on other system components

Collaboration - The properties and behavior of system components are inextricably intermingled

problem requirements definition: identification of data & operation


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What is systems engineering

Systems Engineering (SE) is an interdisciplinary field of engineering, that focuses on the development and organization of complex artificial systems.

Systems Engineering integrates other disciplines and specialty groups into a team effort, forming a structured development process that proceeds from concept to production to operation and disposal.

Systems Engineering considers both the business and the technical needs of all customers, with the goal of providing a quality product that meets the user needs

Structured development process: Analysis vs Synthesis


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(SE)(SE)22: System Engineering vs Software Engineering: System Engineering vs Software Engineering What is systems engineering process


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What we learn from systems engineering

Break down: Problem Definition (PRD)

Model&Interface: Problem Design (SDD)

Unit coding: Programming (SPP)

Put-together: Integration (SIP)


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VV

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VVFrom Conceptual to Complete

From break-down to put-together

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VRequirement Analysis

Functional Analysis/Allocation

Integration / Synthesis

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VRequirement Analysis

Functional Analysis

Functional Allocation

Problem Definition (PRD)-- Identify external entities-- identify major components -- identify links (dataflow)

Problem Design (SDD)-- functional allocation -- activities & interface-- identify further components -- identify links

PRD & SDD

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(SE)(SE)22: System Engineering vs Software Engineering: System Engineering vs Software Engineering What we’re going to do with DFD

VV

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V

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PRD:-- External Entities Customer Keypad Card Reader Control System Customer Display Printout Dispenser Cash Dispenser

-- Functional Level-0 Auto Teller System

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VPRD (Refined):-- External Entities-- Functional Level-1 Receive operator command Verify PIN from card Display customer options Prepare command Update display Prepare message Prepare printout Mange withdrawal

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VSDD (description):The CheckPIN procedure handles the verification of the customer's Personal Identification Number (PIN) using data retrieved from the card's magnetic strip. The procedure invites the customer to enter their PIN using the keypad. If this does not match the PIN stored on the card, a limited number of retries is permitted, after which the card is confiscated as a security precaution. If the correct PIN is entered, the Services procedure is called.

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VSDD (pseudo-code):PROCEDURE CheckPINCONSTANTS MAXPINS IS 3VARIABLES PINCounter IS NUMBERBEGIN read data from card set PINCounter to zero LOOP UNTIL PINCounter is equal to MAXPINS input PIN from customer keypad IF entered PIN matches card PIN THEN EXITLOOP ENDIF add 1 to PINCounter ENDLOOP IF PINCounter is equal to MAXPINS THEN confiscate customer's card ELSE CALL PROCEDURE Services ENDIFEND CheckPIN

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What we’re going to do with DFD

Problem Requirements Definition (PRD)

PRD0 = Major_Operation + ∑ External_entities

PRD* = ∑ Functional_allocation (tasks) + ∑ Dataflows

Software Design Document (SDD)

SDD = ∑ Functional_Description (strategic psuedo-code)

Software Project Plan

SPP = ∑ Scheduled Implementation (coding & testing plan)


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Data Pool

Op1 Fun2 Op3 Fun4

Program = DataStructure + Algorithm:/* Data Pool */ … …void Op1 (… …) {}int Fun2 (… …){}void Op3 (… …){}float Fun4 (… …){}

int main (){ … …}


Thank you very much!

Questions?

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August 13, 2015 1 August 13, 2015August 13, 2015August 13, 2015 Azusa, CA Sheldon X. Liang Ph. D. Software Engineering in CS at APU Azusa Pacific University,

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