Software Engineering Fundamentals

Introduction to Software Engineering

• Software Engineering 10th Edition by Ian Sommerville can be used as a textbook

Course Outline

• Software Engineering Fundamentals
• Software Process Models
• Requirements Engineering
• System Modeling
• Architectural Design
• User Interface Design
• Agile Software Development
• Software Testing

Course Assessment

• Final Exam: 40 marks
• Midterm Exam: 25 marks
• Quizzes: 15 marks
• Project: 20 marks
• The total marks for this course is 100.

Computer Science Career Path

• Careers include Software Analyst (System Analyst), Software Designer, Software Developer (Programmer) and Quality Engineer (Software Tester)
• Many positions/titles exist in Cyber Security, Artificial Intelligence, etc.

Software Engineering

• The economies of all developed nations are dependent on software.
• More and more systems are software controlled.
• Software engineering is an engineering discipline that is concerned with all aspects of software production.

Software Costs

• Software costs often dominate computer system costs.
• With PCs, software costs are often greater than the hardware cost.
• Software costs more to maintain than it does to develop.
• Software engineering is concerned with cost-effective software development.

Software Project Failure

• Increasing system complexity and demands that change drive even more complex systems that require new capabilities.
• Failure to use software engineering methods leads to expensive, less reliable software.

FAQ

• Software constitutes computer programs and associated documentation.
• Fundamental software engineering activities include software specification, development, validation and evolution.
• Computer science focuses on theory and fundamentals; software engineering focuses on the practicalities of developing and delivering useful software.
• System engineering includes all aspects of computer-based systems development, including hardware, software, and process engineering.
• Key challenges facing software engineering are coping with increasing diversity and demands for reduced delivery times, and developing trustworthy software.
• Development costs comprise about 60% of software costs, and testing accounts for 40%. Custom software sees evolution costs that exceed development costs.
• No software engineering technique is the best, as different techniques are appropriate for different types of systems

Software Products

• Generic products are stand-alone systems marketed and sold to any customer.
• Examples of generic products are PC software such as graphics programs, project management tools; CAD software.
• Customized products are commissioned by specific customers to meet their own needs.
• Examples of customized products include embedded control systems, air traffic control software, and traffic monitoring systems.

Product Specification

• For generic products, the software developer owns the software specification and decides on software changes.
• The customer owns the software specification and decides on changes to customized software products.

Essential Attributes of Good Software

• Maintainability: Software evolves to meet changing customer needs.
• Dependability and security: Software should not cause physical or economic damage in the event of system failure, Malicious users should not be able to access or damage the system. Dependability incudes reliability, security and safety.
• Efficiency: Software should not make wasteful use of system resources
• Acceptability: Software must be understandable, usable and compatible with other systems.

Software Engineering Definition

• Software engineering is an engineering discipline concerned with all aspects of software production from the early stages of system specification through maintenance.

Importance of Software Engineering

• Society relies more and more on advanced software systems.
• Software engineering methods and techniques help produce reliable and trustworthy systems economically and quickly.
• It is usually cheaper in the long run to use software engineering methods.
• The majority of costs for most systems are the costs of changing the software after it has gone into use.

Software Process Activities

• Software specification is where customers and engineers define the software to be produced with constraints on its operation.
• Software development is where the software is designed and programmed.
• Software validation is where the software is checked to ensure that it is what the customer requires.
• Software evolution is where the software is modified to reflect changing customer and market requirements.

Software Engineering Diversity

• There are many different types of software system
• There is no universal set of software techniques that is applicable to the different types of software system.
• The software engineering methods and tools used depend on the type of application being developed, the requirements of the customer, and the background of the development team.

Application Types

• Stand-alone applications run on local computers with all necessary functionality without needing a network.
• Interactive transaction-based applications execute on a remote computer and are accessed by users from their own PCs.
• Embedded control systems control and manage hardware devices, and are probably more numerous than any other type of system.
• Batch processing systems refers to business systems designed to process data in large batches and create outputs.
• Entertainment systems refers to systems primarily for personal use intended to entertain the user.
• Systems for modelling and simulation refers to systems developed by scientists and engineers to model physical processes or situations.
• Data collection systems collect data from their environment using a set of sensors and send that data to other systems for processing.
• Systems of systems are composed of a number of other software systems.

Software Engineering Challenges

• Key challenges include Heterogeneity, delivery and trust:
• Heterogeneity concerns building software that can cope with heterogeneous platforms and execution environments.
• Delivery involves developing techniques for faster software delivery.
• Trust involves developing methods that demonstrate software can be trusted by its users.

Systems Development Life Cycle (SDLC)

• A traditional methodology for developing, maintaining, and replacing information systems.
• An orderly set of activities conducted and planned for each development project.
• Each phase has specific outcomes and deliverables that feed important information to other phases.
• SDLC phases include Planning, Analysis, Design, Implementation, Maintenance
• Outputs include software, documentation, and training for users.

SDLC Planning Phase

• Purpose: To determine why an information system should be built (need) and how the project team will build it (plan).
• Consists of two steps: Project Initiation and Project Management
• Project Initiation defines the business needs and how the system create a business value and includes a Feasibility Analysis (Technical, Economic, and Organizational)
• Project Management: Involves the project manager creating a work plan and staffing the project.

SDLC Analysis Phase

• Focuses on who will use the system, what the system will do, and where and when it will be used.
• Sub-phases include Requirements Determination and Requirements Structuring
• Requirements Determination consists of a careful study of organization current procedures and the information systems used to perform organizational tasks.
• Requirements Structuring focuses on relationships between requirements and eliminating redundancy

SDLC Design Phase

• Converts the recommended solution to system specifications
• Defines how the system will operate regarding hardware, software, network, user interface, forms, reports, programs, databases, and files.
• Includes Logical design by describing functional features independently of a specific computer platform
• Includes Physical design by transforming logical specifications to technology-specific details.

SDLC Implementation Phase

• Involves coding, validating, installing, and supporting the information system.

SDLC Maintenance Phase

• Systematically repairs and improves the information system
• Maintenance is not a separate phase but a repetition of other life cycle phases.

Computer-Aided Software Engineering (CASE)

• CASE tools support various SDLC activities.
• They assist in multiple phases of the SDLC: project identification and selection, initiation and planning, analysis, design, implementation, and maintenance.
• Product and tool integration are made possible via an integrated and standard database called a repository.
• Example products: Oracle Designer, Rational Rose
• Diagramming tools: Enable graphical representation of system process, data, and control structures.
• Computer display and report generators: Help prototype how systems "look and feel.”
• Analysis tools: Automatically check for incomplete, inconsistent, or incorrect specifications in diagrams, forms, and reports.
• Central repository: Enables integrated storage of specifications, diagrams, reports, and project management information.
• Documentation generators: Produce technical and user documentation in standard formats.
• Code generators: Enable the automatic generation of program and database definition code directly from design documents, diagrams, forms, and reports.