Software Engineering

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Software Engineering

• Dr. Mohamed Fayad, Associate Professor
• Department of Computer Science Engineering
• University of Nebraska, Lincoln
• Ferguson Hall, P.O. Box 880115
• Lincoln, NE 68588-0115
• http//www.cse.unl.edu/fayad

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Lesson 1 Introduction
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Lesson Objectives

• Understand what software engineering is
• and why it is important
• Know the answer to key questions which
• provide an introduction to software
• engineering
• Understand ethical and professional issues
• which are important for software engineers

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What is software?

• Computer programs and associated documentation.
• Software products that may be developed for a
  particular customer or may be developed for a
  general market.

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What is software engineering?

• Software engineering is an engineering discipline
  which is concerned with all aspects of software
  production.
• Engineering discipline
• All aspects of software production
• software development aspects
• Software project management
• The development of tools, methods, and theories
  to support software production

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Software Engineering vs. Computer Science

• Computer Science is concerned with theory and
  fundamentals
• Software engineering is concerned with the
  practicalities of developing and delivering
  useful software products.

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Software Process

• Software process is a set of activities Whose
  goal is the development or evolution of software
• These activities are mostly carried by software
  engineers.
• There are three level of software process
• Macro-development process covers monthly to
  yearly activities, such as waterfall model,
  spiral model, or UML which consists of analysis,
  design, coding, and testing.
• Mini-development process covers a daily to
  weekly activities of a small team of developers,
  such all the activities within one phase of the
  development.
• Micro-development process covers the daily
  activities of an individual developer, such as
  inspecting a part of a document.

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Software Process Models

• Software engineering life cycles or phased
  software development models, such as
• Waterfall model
• Prototyping
• Spiral Model
• Automatic Programming
• Reuse Models
• Incremental Model
• Fountain Model

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Waterfall Model
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Prototyping
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Spiral Model
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AUTOMATIC PROGRAMMING
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REUSABLE MODULES
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OTI-93F-0014
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INCREMENTAL MODEL
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FOUNTAIN MODEL
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Further
Maintenance
Acceptance
Development
into Library
Program
Use
Further
System
Maintenance
Development
Testing
Testing
Coding
Coding
Design
Module
Software
Design
Requirements
Specification
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Module
Requirements
Specification
Analysis
Henderson-Sellers90
Real-World Systems
Real-World Entity
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The Cost of Software Engineering

• Req. Analysis 40
• Design 20
• Coding 10
• Testing 30

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Software Engineering Methods

• Software engineering methods are structured
  approaches to software development which include
  system models, notations, rules, recommendations,
  design heuristics, and process guidance
• Examples
• Structured Analysis (SA) DeMarco 78
• Object-Oriented Methods, such as OMT Rambaugh,
  et al., 91, and UML Booch, Rambaugh, Jacobson
  99

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Method Components
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Computer-Aided Software Engineering

• Software tools which are intended to provide
  automated support for software development.
• CASE tools are often used for method support.
• There are two types of CASE tools
• Upper-CASE tools support analysis design
• Lower-CASE tools support implementation testing

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Essential Attribute of Good Software

• The software should deliver the required
  functionality and performance to the user and
  should be maintainable, dependable, and usable.
• Maintainability
• Dependability
• Efficiency
• Usability

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Challenges Facing Software Engineering

• 1. Software size has outpaced development
  methods.
• The Delivery Challenge
• 2. Large software teams are difficult to
  coordinate.
• The Managerial Challenge
• 3. Interoperability of multiple systems is
  difficult to test.
• The Heterogeneity Challenge
• 4. Upgradeable and maintainable systems are
  difficult to develop.
• The Legacy Challenge
• 5. Engineering "high-reliability" software is not
  well understood.
• The Engineering Challenge
• 6. Upgrades are often expensive due to regression
  testing.
• The Business Challenge

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Discussion Questions

• T/F
• Software design is part of the software life
  cycle.
• Software design is part of the software
  maintenance cycle.
• Define
• Automatic Programming and Fountain Model
• What are the differences between a software
  process model and a software process?
• Identify other problems and challenges that
  software engineering is likely to face in the
  21st century

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Questions for the Next Lecture

• Define the following terms
• Methodologies and Paradigm.
• Method and Process
• Model and View
• Technique and Tool
• Environment
• Heuristics
• What are the essential properties of modeling?
• What are the essential properties of process?
• What are the differences between a method and a
  process?
• What are the differences between a model and a
  view?

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Tasks for Next Lecture

• Task 1 Problem Statement for individual
  assignments are needed (see sample problems on
  the course web site). This is due on the second
  week of the semester.
• Task 2 Think About a problem statement for your
  team Project (see sample problems on the course
  web site). This is due on the third week of the
  semester.
• Task 3 Identify the team members of your team.
  E Mail me their names, e-mails, phone numbers.
• Task 4 Read Chapter 1 Transition to OOSD
• Please note that problem statements must be
  submitted electronically as MS Word format.

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