Conceptual Modeling and Dependency Graph Analysis

Lecture 11 of SE602 Software Re-Engineering explores conceptual dependency modeling and graph-theoretic analyses in legacy software audits. A software system can be modeled as a directed graph where nodes represent computational entities (methods, classes, modules) and edges represent dependencies (function calls, inheritance, variable access, module imports). Students study Dependency Structure Matrices (DSM), learning how to arrange architectural layers to expose undesirable cyclic dependencies and tangled cross-module coupling. The lecture demonstrates Tarjan strongly connected components algorithm for detecting dependency cycles, explaining why circular package dependencies severely degrade software testability, modular comprehension, and deployability in mission-critical applications. Comprehensive coverage of standard academic benchmarks ensures learners communicate with technical precision across software engineering disciplines. Detailed analysis of code smell topologies highlights the imperative of eradicating duplicate logic, long methods, and bloated god classes. Test harness construction including characterization testing and regression suites are contrasted with traditional unit testing strategies. Students evaluate the trade-offs between big-bang system rewrites and progressive evolutionary refactoring in mission-critical environments. The lesson explores cognitive program comprehension models, top-down hypothesis validation, and mental mappings of complex legacy architectures. Practical code illustrations demonstrate safe code transformations, automated refactoring preconditions, and behavioral equivalence preservation. Scholars analyze Chidamber-Kemerer object-oriented metrics including WMC, CBO, and RFC to quantify the architectural impact of refactoring. Cloud migration pathways including rehosting, replatforming, and cloud-native refactoring are examined as extensions of legacy modernization. The relationship between technical debt accumulation, architectural degradation, and long-term enterprise software viability is reinforced. In this lecture, students examine formal methodologies, structural transformations, and analytical metrics of software re-engineering systems. Through detailed theoretical breakdowns, the lesson explores software evolution dynamics, legacy system preservation, and maintainability enhancement. Special emphasis is placed on reverse engineering workflows, abstract syntax tree construction, and program dependency representations. Mastering these foundational software re-engineering paradigms empowers software engineers to systematically revitalize enterprise legacy platforms. Analytical exercises and architectural traces help students prepare thoroughly for Virtual University midterm and final term examinations.