Songhwa Chae

Volunteer Matching Web Platform

Developed a web-based platform for matching university students with volunteer opportunities.

Tech Stack

Java, Spring Boot, MySQL, JavaScript, jQuery

Responsibilities

• Designed and implemented RESTful APIs for user and matching functionalities
• Developed frontend features for user interaction and data display
• Designed database schema and wrote optimized SQL queries

Key Contributions

• Built end-to-end matching workflow between users and volunteer programs
• Structured API and database interaction for efficient data handling
• Improved data consistency through input validation and backend logic

Impact

• Enabled efficient volunteer matching process for university users
• Improved usability and data reliability of the platform

Legacy System Modernization (Flash to Web Application)

Migrated a legacy Flash-based learning system into a modern web application without access to the original source code by reverse-engineering client-server communication.

Tech Stack

Java, Spring Boot, Tibero, AngularJS, XML, Wireshark

Responsibilities

• Reverse-engineered existing Flash application behavior by analyzing network traffic
• Captured and inspected request/response packets using Wireshark to identify APIs and data structures
• Reconstructed backend communication logic and redesigned it into RESTful APIs
• Converted Flash-based functionalities into web-based features using JavaScript and jQuery
• Refactored and restructured system architecture for improved maintainability

Key Contributions

• Successfully rebuilt system functionality without original source code by analyzing network-level communication
• Identified hidden API endpoints, request patterns, and data formats through packet inspection
• Reimplemented core features with a modern, scalable web architecture
• Reduced technical debt by replacing tightly coupled legacy logic with modular backend services

Impact

• Eliminated dependency on deprecated Flash technology
• Enabled continued service operation despite lack of original source code
• Improved system maintainability, scalability, and extensibility
• Enhanced accessibility by transitioning to a browser-based platform compatible with modern environments

Campus Mobile Payment System (SU-Pay)

Developed a campus-wide mobile payment system (SU-Pay) that allows students to use scholarship-based points earned from extracurricular activities as digital currency at on-campus stores. Integrated into the university’s official mobile app, this system was the first of its kind among universities in Korea.

Tech Stack

Java, Spring Boot, Spring Batch, JavaScript, Angular JS, MySQL

Responsibilities

• RESTful API Design & Core Logic Development: Architected and implemented scalable REST APIs to handle seamless data communication across the payment ecosystem.
• Third-Party Auth Integration (Danal): Integrated Danal’s identity verification API to ensure robust security and mandatory real-time user authentication for financial transactions.
• Batch Processing Engine Engineering: Designed and developed a Spring Batch-based engine to analyze Extracurricular Program completion data and automate high-volume point distribution.
• Full-Stack Feature Implementation: Developed end-to-end marketing-related logic, such as event-based point accumulation, along with interactive frontend interfaces using JavaScript and jQuery.

Key Contributions

• Systematized Identity Verification: Established a secure and reliable verification process for payments and cash-out services by successfully integrating professional external authentication modules.
• Automation of Manual Workflows: Replaced labor-intensive manual point distribution with an automated batch system, significantly reducing administrative overhead and eliminating human error.
• Data Integrity & Transaction Management: Enforced strict transaction management strategies within the reward logic to prevent duplicate payments and ensure 100% data consistency.
• End-to-End User Flow Optimization: Directly implemented the entire flow from event participation to real-time point confirmation, enhancing overall service engagement and user satisfaction.

Impact

• Enhanced Security & Trust: Achieved high reliability in financial operations by meeting the rigorous security requirements for digital currency services through verified identity protocols.
• Operational Efficiency: Drastically improved processing speed and accuracy for campus-wide rewards, allowing the administration to focus on strategic tasks rather than manual data entry.
• Service Scalability: Built a modular architecture that successfully bridged the gap between the payment system and the Extracurricular Promotion System, proving the platform's extensibility for future campus services.

Media

• Sahmyook University News
• Promotional Posting on the University's Website

Kookmin University Integrated Mobile Platform (ON Kookmin)

A comprehensive 'One-Step' campus solution integrating academic administration, community features, and automated data synchronization.

Tech Stack

Java, Spring Boot, MySQL, AngularJS

Responsibilities

• Academic Data Synchronization Engine Design: Architected and developed a high-volume data synchronization engine using Spring Batch to bridge the gap between the university’s legacy academic databases and the mobile service database.
• Core Service API & Database Schema Design: Designed the backend architecture and RESTful APIs for mission-critical features, including personalized student schedulers (timetables) and real-time course bulletin boards.
• Database Table Automation: Engineered automated logic for dynamic database table creation and management to ensure system scalability and reduce manual DDL (Data Definition Language) overhead.
• Full-Stack Feature Development: Developed responsive frontend interfaces and administrative dashboards using a hybrid tech stack of AngularJS, jQuery, and Bootstrap.

Key Contributions

• Massive Notification & Email Engine: Built a robust automated notification system using Spring Batch to handle bulk email distribution to tens of thousands of students with real-time delivery status tracking.
• Optimized Resource Management: Implemented PagingItemReader and chunk-oriented processing in batch jobs to maintain 100% data integrity while minimizing memory footprints during peak load.
• Complex Logic Modeling: Successfully translated intricate academic regulations (course schedules, prerequisites, and attendance rules) into efficient database models and backend business logic.
• Infrastructure Reliability: Established "Restartability" in batch processes, allowing the system to resume from the point of failure in case of network or SMTP timeouts during bulk operations.

Impact

• Enhanced Information Accessibility: Improved the student experience by consolidating fragmented academic services (schedules, attendance, and communication) into a single, reliable mobile entry point.
• Dramatic Operational Efficiency: Reduced manual administrative tasks by automating data updates and table management, allowing the IT team to focus on feature enhancements rather than routine maintenance.
• Scalable Architecture: Delivered a modular and automated backend structure that successfully supported a high-traffic environment with tens of thousands of active users.
• Modernization of Academic Services: Transitioned traditional paper-based or web-only notifications into a modern, mobile-first notification system, increasing student engagement.

Link

• Google Playstore
• App Store