CP317 Software Engineering Week 4-1: Low-Level Design

CP317 Software Engineering - Week 4-1: Low-Level Design (Part 1)

• Course: CP317 Software Engineering
• Week: 4-1
• Topic: Low-level design (detailed design)
• Instructor: Shaun Gao, Ph.D., P.Eng.
• Agenda Topics:
  • Review of week 3-2 topics (UML diagrams, race conditions, design principles of decomposition, cohesion, and coupling).
  • Low-level design concept and key tasks.
  • Detailed design creation, including interface design (internal and external), GUI design, internal component design, data design, and documentation.
  • Evaluating detailed design and managing implementation.
  • Summary of low-level design.

Review of Week 3-2 Topics

• UML Diagrams: Unified Modeling Language diagrams, including structure diagrams (class diagrams, component diagrams), behavior diagrams (use case diagrams, state transition diagrams, sequence diagrams).
• Design Principles: Decomposition, cohesion, and coupling are critical for both architecture design and detailed design.
• Race Conditions: A situation where several processes try to access and modify the same shared resource at the same time, potentially leading to inconsistent results.

Low-Level Design (Detailed Design)

• Concept: Detailed design is the process of refining and expanding the software architecture to a level that allows implementation. It provides detailed specifications of internal components, including data structures, algorithms, and processing.
• Key Tasks:
  • Understanding Architecture and Requirements: Thorough understanding of the system requirements and architecture is crucial for allocating components with the right responsibilities. This includes identifying cohesion and coupling properties within components.
  • Creating Detailed Design: Designing the interface (internal and external), GUI, data design, and internal component structure are key for efficient software implementation.
  • Interface Design (internal): Defines how components interact.
    • Methods: Shared memory, concurrency, message passing, Inter-process communication (IPC).
  • Interface Design (external): How the software interacts with external users, devices, or systems. Ex. GUI design, protocols like TCP/IP or serial (RS-232C), and microcontroller communication.
  • GUI design: Graphical User Interface to provide users with an interactive way to interact with a system.
  • Internal Component Design: Diagram showing internal component structure and behaviour including UML structure diagrams, class diagrams, component diagrams, UML behavior diagrams, use case diagrams, state transition diagrams, and sequence diagrams.
  • Data Design: Defining data structures and types relevant to the software's components and functions.
  • Data Structures: Arrays, stacks (LIFO), queues (FIFO), linked lists(singly and doubly).
  • Documenting Detailed Design: Creating a Software Design Document (SDD) detailing design decisions, specifications, and components.
  • Evaluating Detailed Design: Technical reviews to evaluate design for correctness, completeness, and efficiency using techniques like technical review meetings with time notice, input from technical expert, testing team, requirements validation.
  • Managing Implementation: Includes creating an implementation plan, defining a model, and delegating tasks.

Specific Design Topics

• Shared Memory / Concurrency: Techniques for sharing data between multiple parts of a program concurrently, which may cause race conditions.
• Graphical User Interface (GUI) design: This is one way for Users to interact with a system's software.
• ASCII: Describes coding for communicating between devices which uses a code table (ASCII table) for unambiguous and well-understood character exchange and representation.

Software Design Documents (SDD)

• Table of Contents Example: A typical SDD includes sections like Introduction, Software Architecture, Detailed Design, and Conclusion. Sections like Date of Issue, Scope, Issue organization, Authorship, and References are also important.

Additional Information

• .NET & Programming Technologies: .NET is one language used for programming and in different versions (e.g., .NET Core 3) including in different environments like Desktops, Web programming or cross-platform capabilities.
• Waterfall model: A structured approach to implementing software, following a linear sequential flow.
• Technical reviews: A procedure for evaluating detailed design through structured review, making sure specifications, implementation design and requirements are correct and complete.

Announcement

• Group Formation: 75% of students have formed groups.
• Test 1: A test covering weeks 1-4 will be held on Feb 3rd, requiring laptop completion.
• Location: LH3094