Signal Processing

Cycle Atlanta: Seeing Like a Bike

The Cycle Atlanta project aims at creating sensor systems that allow a bike to "see" its environment and collect data as a participatory effort so that we can help the City of Atlanta to make informed decisions about biking infrastructures. Specifically, a sensor box equipped with sonars, lidars, PM sensors, gas sensors, gyroscope, accelerometer, and others was developed to detect environmental factors that can give rise to cyclists' stress level. I participated in this project as a Data Science for Social Good (Atlanta's DSSG) Summer fellow in 2017.

MapReduce Framework for Swarm Robot Systems

This was a part of research projects conducted under the Basic Research Laboratory Grant from Ministry of Education, Science, and Technology in South Korea. This project is two folds: (1) simulating an application of swarm robot systems; (2) designing a software framework for the swarm robot systems to reduce the complexity of developing applications while minimizing the amount of transmitted data by adopting MapReduce paradigm. The video above is a simulation of a swarm robot system application that searches for red pillars (foraging).

Wireless Price Display System

This project was my final team project for "Electrical Engineering Laboratory 3" class in 2004 (when I was junior in college). The goal was to make a wireless system that substitutes price tags with electrical displays in grocery stores. The base station manages a list of products in the database, and it sends out price information to receiver units. Receiver units are simple character displays having unique IDs. When any products' prices change, the system can easily update new prices on these displays. 

Development of a VoIP Testing Program

Skype's SILK codec was tested as an exploratory project to see if there was an opportunity to integrate real-time audio communication with smart TVs. This project was conducted as an internship project in LG Electronics' LCD TV Research Lab in 2010. Siwon Yang (currently, a developer at Hyundai Mobis) and I implemented a VoIP testing program on Linux using C and SLIK codec APIs. The video is a demo of the testing program.

Large-scale News Image Analysis with MapReduce-based LSH and VisualRank

Hao Li (Ph.D. student from CS) and I conducted a big-data analysis project using the MapReduce framework (Hadoop) for the final project of INFM718G (Data-Intensive Computing with MapReduce, by Dr. Jimmy Lin). Targeting all the news images in April 2013, we tried to rank news images based on the importance and popularity level of each news image. To do that, we extracted image features using SIFT (Scale-invariant feature transform) and constructed a graph of images using LSH (Locality-sensitive Hashing) as a means to approximate the similarity of images.

Human-Robot Interaction via Sound

This prototype was an intermediate result of a robot-human interaction project conducted at Torooc Inc., a start-up company where I was a co-founder and Director of Software Development, in 2011. I first designed microphone amplifier circuits using transistors and amplifier chips, respectively. Then, I connected three microphones to Texas Instruments' Stellaris LM4F embedded board. On top of that, I implemented a Time-Difference of Arrival (TDOA) algorithm in C language.