Module 7: CS System Design Artifacts in Research

Master how CS engineering modeling artifacts (Context Diagrams, Use Case Diagrams, Activity Diagrams, ERDs, and 3-Tier Architecture) serve as essential evidence in Chapter 4 of your research project.

Part 1: Modeling Diagrams in CS Research Reports

M7-Q01 [DRAFT & OUTLINE]

Explain the role of a Context Diagram versus a Use Case Diagram in a CS research report (e.g. Chapter 4 Analysis & Design). What does each diagram model? [6 Marks]

NUST Model Answer [6 Marks]:

Context Diagram (Current Baseline System): Models the proposed system or legacy process as a single central process entity surrounded by external entities (e.g., Student, Invigilator, Exam Dept) and external data flows. It defines the system boundary and baseline scope.
Use Case Diagram (Proposed Research System): Models internal system functional requirements from the user perspective, highlighting specific actors, system boundary, use cases (e.g., Tap NFC Card, Scan Fingerprint, Auto-Record Attendance), and «include» / «extend» relationships.

M7-Q02 [APPLY & SOLVE]

Draft an Activity Diagram logic flow for a Biometric Examination Identity Authentication System at exam entry. Include decision nodes and error branches. [6 Marks]

NUST Model Answer [6 Marks]:
Sequential Logic Flow:

[Start Node] → Student arrives at exam hall entrance.
[Action: Tap NFC Card] → Hardware NFC reader extracts student UID and fetches stored fingerprint template from local SQLite DB.
[Action: Scan Fingerprint] → Optical biometric sensor captures live minutiae template.
[Decision Node: Match?]
↳ IF NO (Mismatch / Unregistered) → Flag alarm, set status to ENTRY_DENIED, log incident, and route to Manual Invigilator Desk [End].
↳ IF YES (Authenticated) → Open physical turnstile gate, record timestamped ENTRY_VERIFIED in database [End].

M7-Q03 [CLASSIFY & GROUND]

Describe a 3-Tier System Architecture for a CS research prototype and explain why decoupling the Hardware, Application, and Data layers is necessary for scientific controlled evaluation. [6 Marks]

NUST Model Answer [6 Marks]:

The 3 Layers:

1. Hardware / Perception Layer: Physical sensors (NFC reader, fingerprint scanner, microcontrollers).
2. Application / Logic Layer: Matching engine, biometric comparison algorithm, web dashboard, and API client.
3. Data Layer: Relational database (SQLite/PostgreSQL) storing student records, minutiae templates, and logs.

Why Decoupling is Essential in Research:
Decoupling allows researchers to isolate variables during performance testing (e.g. testing the speed of a new fingerprint matching algorithm in Layer 2 without altering physical sensors in Layer 1 or database schemas in Layer 3).