Career Profile

Hello! I’m passionate about privacy-preserving data sharing and solving real-world optimization problems such as in distributed systems or ML systems. I’m currently pursuing a Master’s degree in Information Technology at Carnegie Mellon University, and I’m looking for a full-time software engineer position starting in December 2023.

Experiences

Research Assistant

May 2023 - August 2023
Carnegie Mellon University, Pittsburgh, PA
  • Collaborating with Professor Fanti to evaluate deep generative models for time-series data generation and long-range forecasting

Software Engineer

Jan 2021 – July 2022
Samsung Research, Seoul, South Korea
  • Built AWS-based Microservice Architecture with Kubernetes(k8s) and enabled Infra as Code(IaC) by Terraform
  • Designed and implemented active-passive multi-region infrastructure for the reliability of large-scale cloud services
  • Designed and built a web dashboard for developers to manage isolated k8s clusters based on React/Backstage
  • Designed and developed RESTful backend services using PostgreSQL, AWS DynamoDB, Golang, and Typescript
  • Earned Certified Kubernetes Administrator(CKA) and operated AWS EKS clusters for cloud-based applications

Software Engineer & Internship

July 2019 – Dec 2020
IoTeX, Start-up in Silicon Valley, CA
  • Drove a slashing project from design to implementation to mitigate Nothing-At-Stake attack in Proof-of-Stake systems, and released it to Mainnet; thereby enhanced the consensus security of open sourced IoTeX blockchain
  • Improved the performance of log searching API by introducing bloom filter indexer for a long range query
  • Developed smart contracts to enable a transaction privacy in blockchain using zkSNARKs and token economy, so-called cyclone protocol and managed the product from frontend to backend, leading to production
  • Implemented and published an academic paper regarding an extensible and modular PoS staking architecture in IoTeX blockchain

Projects

Usable Privacy Enhancing Technologies (PETs); Differential Privacy - Conducted a study evaluating the usability of randomized respone technique for privacy-preserving sensitive data sharing; Accepted at SOUPS poster/workshop 2023
Asynchronous Federated Learning with DAG-based Blockchain in Edge Computing - Led a 5-person team at Seoul National University blockchain academy, authoring a survey paper on integrating asynchronous federated learning (FL) and directed acyclic graph-based blockchain for edge computing
The Impact of Blockchain on Open Banking System - Surveyed the impact of blockchain on financial industry in terms of payment data utilization, and won a Grand Prize in the 8th Fin-Tech Idea and Paper Competition at Korea Internet Security Agency (KISA)

Open Source Contributions

IoTeX Blockchain Core Protocol Development - Contributed to the development of IoTeX blockchain core protocol, including the implementation of slashing, staking and consensus in GoLang
Transaction Privacy Protocol in Blockchain using zkSNARKs - Contributed to the smart contract development of transaction privacy protocol in blockchain using zkSNARKs and token economy, so-called cyclone protocol

Publications

  • Asynchronous federated learning with directed acyclic graph-based blockchain in Edge computing: Overview, design, and challenge
  • S. Ko, K. Lee, H. Cho, Y. Hwang, and H. Jang
    Expert Systems with Applications, 2023
  • EMS: An Extensible and Modular Staking Architecture for Proof-of-Stake Systems
  • S. Ko, X. Fan, Z. Zhong, Q. Chai
    IEEE The 2nd International Conference on Blockchain Computing and Applications (2020)

    Skills & Proficiency

    Golang

    Python

    C & C++

    Javascript & Typescript

    Solidity

    Terraform

    Docker & Kubernetes

    SQL & NoSQL

    AWS & GCP