What is Software Engineering?

• Software engineering is the application of scientific and practical knowledge to invent, design, build, maintain, and improve structures and processes.
• Software consists of integrated programs and a carefully organized set of instructions and code.
• Software engineering is a branch of engineering focused on the evolution of software products.
• Software engineering employs scientific principles, techniques, and procedures systematically.
• Software engineering focuses on creating reliable and effective software.

Why Software Engineering is Necessary

• Software Engineering is necessary because
• To manage large scale software projects
• To achieve greater scalability
• To manage costs effectively while still producing necessary software
• To manage the dynamic nature of software to better adapt to a changing world
• To achieve better quality management
• The increasing rate of progress in meeting user needs.
• High programmability involves systematic approaches, especially when making extensive software
• Adaptability becomes manageable with a scientific basis, making scaling easier.
• Hardware costs decrease, but software costs remain high without good processes.
• Ever-changing environments require continuous updates, thus dynamic nature.
• Quality management requires better procedures for developing better quality software.

Characteristics of a Software Engineer

• Systematic methods and computer fundamentals are key.
• Programming, communication, and teamwork skills are essential.
• Motivation and discipline are important personal qualities.

Importance of Software Engineering

• Software engineering reduces complexity.
• Large software systems are complex, and software engineering breaks them into smaller problems.
• Each problem is solved independently and integrated at the end.
• Software engineering minimizes cost by providing systematic methods for estimating budgets and controlling costs.
• Large-scale software development requires numerous resources, including labor, licenses, and hardware.
• Software engineering decreases time by planning and managing deadlines efficiently.
• Delivering projects on time is a major challenge, and calendar conflicts are common, particularly in implementation.
• Software engineering handles large projects by providing methods for managing complex projects effectively.
• Large projects require planning, management, and testing.
• Software reliability indicates the probability that software will operate without failure over time.
• Software engineering provides models for measuring and evaluating software quality.
• Effectiveness involves achieving desired results efficiently, including communication, technology use, and resources.
• Effectiveness leads to satisfied customers and high-quality work

Software Engineering vs. Computer Science

• Software engineering focuses on applying engineering processes to design, create, and maintain software.
• Computer science focuses on theory and fundamentals, applying abstract and concrete knowledge.

Job outlooks for software engineers

• Software developer: High compensation and skill acquisition with a median salary of $105,811.
• Data scientist: High demand and competitive salary, diverse applications, with salary ranges from $128,248 to $156,569.
• Cybersecurity analyst: High demand, lucrative salaries, and transferable skills with a median salary of $96,735.
• Software engineering is a systematic approach to software development of systematic applications.
• Software Engineer applys the principles of software engineering to design, develop, maintain, test, and evaluate computer software.
• Programmers do not necessarily utilise engineering education or techniques.
• Software engineering is a systematic, disciplined, quantifiable approach to software development, operation, and maintenance.
• Air traffic control systems monitor aircraft in real time, detect collisions, and optimize routes.
• Air traffic control systems are essential for air transport safety and efficiency.

Application of Software Engineering in Air Traffic Control

• Monitor all aircraft positions and alert controllers to potential collisions in real time.

• System architecture: A distributed architecture allows data servers, user interfaces, and communication systems to work together.

• Abstraction: The system is divided into modules for easier management.

• Scalability: The system is designed to scale horizontally by adding more servers as flight numbers increase.

• Programming languages such as Java or C++ are used to develop system components.

• Distributed databases store and process large data volumes in real time.

• Secure communication protocols ensure data integrity and confidentiality.

• Load tests ensure the system handles peak air traffic, and failure tests ensure continued function after component failure.

• Regular updates fix bugs and add features, while continuous monitoring maintains system stability.

• Systematic: Development follows clear steps, including requirements, design, implementation, testing, and maintenance.

• Disciplined: Strict quality and safety standards are followed.

• Quantifiable: System performance is continuously measured and monitored.

• Design should not be confused with programming or requirements engineering.

• Requirements specify what a system should do, while design specifies how it will be built.

• Analysis involves understanding requirements.

• Design organizes and structures the final solution.

• Construction builds a system that satisfies the requirements.

• Drawing involves platform and requirement information with Design inputs

• Architectural design, Interface design, Component design with Design activities to make Database design and System architecture, Database specification, Interface specification and Component specification as Design outputs

Software Architecture

• Software engineering architecture is the high-level structure of a software system and the discipline to create structures.
• Structure: elements, visible properties, and relationships.
• Manner: structures fulfill requirements and behaviors.
• Modularity: Dividing the system into independent modules makes maintenance and development easier.
• Abstraction: Simplifies complexity by hiding unnecessary details, showing only the essentials.
• Reuse: Use existing components to avoid "reinventing the wheel."
• System design represents the link between specification and design.
• Architectural design is an early, critical phase that identifies main components and their communications.

Abstraction Types

• Architecture in the small: Focuses on individual programs (e.g., modules).
• Architecture in the big picture: Focuses on complex enterprise systems (e.g., integration of systems).
• Architecture is represented via Simple, informal block diagrams showing entities and relationships
• The diagrams can lack semantics or fail to show relationships between entities
• Architecture can be represented by Architectural Models.

Software Architecture Model Types

• Monolithic Architecture: Centralized components and functionalities in a single application.
• Layered Architecture: System divided into distinct layers with hierarchical communication.
• Microservices: System composed of small, independent services communicating through APIs.
• Modularity: Facilitates development and maintenance of isolated components.
• Scalability: Allows adding resources as needed.
• Flexibility: Facilitates changes and adaptations.
• Component reuse: Saves time by reusing functionality.
• Maintainability: Easier to fix bugs and implement updates.
• High-level view is useful for communicating with system stakeholders and planning projects because it is not cluttered with details
• Stakeholders can understand an abstract view of the system.
• Provides a complete system model showing components, interfaces, and connections.

Architectural Decisions

• Generic Architecture: Use reusable models like MVC or Microservices.
• System distribution: Determine how components will be distributed.
• Architectural styles: Choose the most suitable style (e.g., layered, service-oriented).
• System structuring: Decide how to organize modules (e.g., functionalities or layers).
• Control strategy: Manage control flow (e.g., centralized vs. decentralized).

Architectural Reuse

• Systems in the same domain often share similar architectures reflecting domain concepts.
• Application product lines build on variants tailored to customer needs.
• The architecture of a system can be designed around proven patterns, using the essence of an architecture via instantiation.
• Locate critical operations and minimize communications, and use large components.
• Security is improved through a layered architecture with critical resources in the inner layers.
• Locate critical features in a small number of subsystems.
• Availability is enhanced with redundant components and fault tolerance mechanisms.
• Use Replaceable components with fine grained
• Various views and perspectives aid in designing and documenting.
• Models can describe architectural notations to expose each viewpoint.

Architecture Patterns

• Patterns offer solutions to recurring problems identified from experience.
• The original proposal came from Christopher Alexander's work.
• A pattern includes context, problem, and solution.
• Standards represent, share, and reuse knowledge.
• Architectural patterns are stylized descriptions of tested design practices.
• Standards should clarify when they are useful.

Model-View-Controller (MVC)

• MVC separates presentation and interaction from system data.

MVC Components

• Model: Manages system data and operations.
• View: Defines how data is presented to the user.
• Controller: Manages user interaction.
• Use MVC when there are multiple ways to view and interact with data or when interaction/presentation requirements are unknown.
• MVC allows data independence and supports multiple representations with shared updates.
• Extra code and complexity may be involved in MVC with simple data models and interactions.