Software Engineering - chp0- introduction

MedTech

Software EngineeringMain Notions, Lifecycle

Dr. L i l ia SFAXIw w w.l i l iasfaxi .w ix.co m/ l i l iasfaxi

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MedTech – Mediterranean Institute of TechnologySoftware Engineering

MedTech

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Speaker Disclosure

• Dr. Lilia Sfaxi• Associate Professor in INSAT• Researcher in LIP2 Laboratory, MASTER team

• PHD in Computer Science from the University of Grenoble and Science Faculty of Tunis

• Software Engineering Degree from INSAT, University of Carthage

Dr. L i l ia SFAXI w w w.l i l iasfaxi .w ix.co m/ l i l iasfaxi

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Software Engineering

MedTech

Speaker Disclosure

• Research Field : Big Data Area• Big Data & Decisional Systems

• Big Data Systems’ Methodology

• Teaching : Main Focus on New Technologies• Big Data • Business Intelligence

• Mobile Applications• Service-based Architectures (SOA, WOA, Microservices, API

Management…)


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MedTech

Speaker Disclosure

• Certifications• ITIL (Information Technology Infrastructure Library) V1

• IBM Mobile Application Specialist (Worklight)

• IBM Big Data Specialist (BigInsight)

• Other Activities• IBM trainer in Mobile Development

• Tra ining of educators in Rabat, Esprit University, Supcom/Isetcom

• Tra ining of students in INSAT, Esprit University, V irtual University of Tunis

• Teacher in the Virtual University of Tunis (UVT) • Mobile Application Development (Android) for 2nd year Professional Master in

Open Source Software (MP2L)


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Speaker Disclosure


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136,189

108

9,474

90

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Summary of the Course

• Software Engineering: An introduction• Importance of Software Development• Definitions

• Software + Engineering• Software Engineering

• Attributes of a good Software• Key Challenges

• SDLC: Software Development Lifecycle• Definition and Actors• Steps

• Requirements Analysis• Design• Implementation• Testing• Release


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SOFTWARE ENGINEERING: AN INTRODUCTIONSoftware Engineer ing


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Importance of Software

• Software is everywhere!

• The economies of all developed nations are dependent on software

• Software costs often dominate system costs

• Software costs more to maintain than to develop!


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Software Engineering: An Introduction

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Definitions: Software

• Computer Programs + Associated Documentation

• Can target:• A particular customer: bespoke/customized software• The general market: generic software

• Software products are:• Intangible

• Complex

• Flexible


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Definitions: Software Engineering

• Engineering• Action of defining and sequencing necessary tasks for the

creation of a new product or service

• Software Engineering• Engineering discipline concerned with all aspects of software

production• Captures the customers’ business needs and specify the

blueprints for the system, so that programmers can implement it


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Software Engineering is the application of a systematic, disciplined, quantifiable approach to the

development, operation and maintenance of software

IEEE’90


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Software Engineers must:• Adopt a systematic and organized approach to their work• Use appropriate tools and techniques

… depending on:• The problem to be solved

• The development constraints• The available resources

... with a given budget

... before a given deadline

... while changes occur!


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A good software …

• delivers the required functionality and performance to the user

• is maintainable : evolves to meet changing needs

• is dependable : must be trustworthy and secure• is usable by its users• is efficient : should not make wasteful use of system

resources• is reusable: can be reused in another form or for other

purposes


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Skills of a Software Engineer

• A software engineer is not (only) a developer!• “ It is not enough to do your best: you must KNOW what to do, THEN do your

best” W. Edwards Deming

• Aside from the technical skills, a software engineer must have other skills :• Communication• Feedback

• Motivation

• Analytical

• Planning

• Risk assessment


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Key Challenges

• Need to master both the technical and business problems

• Software is formal, while the real world is informal• Coping with legacy systems

• Old valuable systems must be maintained, not systematically replaced

• Increasing diversity• Consider the set of mixed and heterogeneous hardware and software

involved in the same system

• Increasing demands for reduced delivery time

• Ethical Responsibility!


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Key Challenges: Ethical Responsibility

• Behaving in a honest and ethically responsible way in order to be respected

• Respect of the confidentiality of the client’s information

• Competence: avoid to misrepresent your competence by accepting a task you cannot do

• Intellectual Property rights: respect of patents, of copyrights• Computer misuse: the employer’s computer must be properly used

• Whether the misuse is trivia l (like game playing) or extremely serious (like the dissemination of viruses)

• See the ACM/IEEE Code of Ethics!


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SDLC: SOFTWARE DEVELOPMENT LIFECYCLESoftware Engineer ing


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SDLC : Definition and Actors

• SDLC: Process of creating and altering systems, and the models and methodologies that people use to develop these systems

• Actors: Mainly (but not only)


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SDLC: Software Development Lifecycle

Customer

Developer

Tester

Designer

Team

Project Manager

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SDLC : Steps


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RequirementsAnalysis

Design

ImplementationTesting

Release

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Step 1 : Requirement Analysis

• Work closely with the customer• Customer can be

• a client,

• your employer,

• or yourself

• Focus on the “What”, not the “How”

• End Result: Functional Specification

• Reviewed by:• Customer, Designer


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R.A.

Design

CodeTest

Release

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Step 2 : Design

• Focus on the “How”• Break the problem into smaller pieces

• Components

• End Result: Design Specification

• Reviewed by:• Designer, Developer


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R.A.

Design

CodeTest

Release

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Step 3 : Implementation

• Write the code according to design• In some cases (oddly) the shortest phase!

• End Result: Executable* Application

• Reviewed by:• Designer, Developer, Tester

* or not…


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R.A.

Design

CodeTest

Release

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Step 4 : Testing

• Verify the code works according to the functional specification

• Look for corner cases

• End Result: Test Plan, A program that works *

• Reviewed by:• Designer, Developer, Tester

* hopefully…


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R.A.

Design

CodeTest

Release

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Step 5 : Release

• Close to the customers (again)

• Validate their expectations• Get feedback for

• Next version

• Maintenance

• End Result: A happy customer and lots of $$$


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R.A.

Design

CodeTest

Release

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SDLC Challenges


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References


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• L. Bonilla, Introduction to Software Engineer ing, Mentorpick.com, 2009

• Mr. Jackman's Computer Programming Class, Software Development L ifecycle , https://www.youtube.com /watch?v=9STHYg7igIQ , consulted the 22nd sept. 2016

• Recommanded Readings• I. Sommerville, Software Engineering (6th edition), Addison Wesley

Publishing Company , 2000

• H Gomaa, Software Modeling and Design: UML, Use Cases, Patterns and Software Architectures