Paul Li: On the Move with Transit Research


September 2, 2004

ECE senior Paul Li is on the move conducting wireless research on security measures for transit systems for the Transportation Research Board (TRB). The busy Integrated M.S./B.S. Degree (IMB) student assists Yang Cai, a systems scientist in the School of Computer Science's Human-Computer Interaction Institute. Their project team includes ECE Professor and Center for Wireless and Broadband Networking Director Dan Stancil (Li took 18-758, Wireless Communications with him) and Mel Siegel from the Robotics Institute.

Li became involved in the study as part of a course assignment in Cai's class. They worked with Richard Shnyder from the Port Authority field testing prototypes and proposing new technical concepts. Let's connect with Li:

Paul Li

ECE Senior


Hong Kong

Why he chose ECE at CMU:

Because I heard that the ECE program in CMU is one of the best in the states and I am very interested in programming and computer hardware.

Research contributions:

At the beginning of the project, I helped Professor Cai to find the suitable equipment, e.g. cameras and wireless cards, for the project. After that, we captured real-time images from the Port Authority Transit (PAT) buses and I started the image processing.

I also wrote Java programs to transfer images between two laptops in an ad-hoc wireless network. They were used to analyze the distance and transfer rate when using different wireless antennas and wireless protocols.


The most challenging part was that I didn't have any experience with image processing. I used MATLAB as the tool and wrote a MATLAB script to detect the moving, human, part of the pictures. There are some techniques (e.g. optical flow) that I learned and used in the script to detect the moving parts. But since there are a lot of variations to light intensity, the result wasn't very accurate. Also, I didn't have a lot of experience with network programming in Java. Now, I am very comfortable doing all of these tasks.


The best thing about being involved in this project is that I can apply what I learned to a real application. Other than that, I also had a chance to try some of the latest network cameras, which are high resolution and wireless ready.

Research time:

Average 10-15 hours per week.

Classroom picks:

18-791, Digital Signal Processing I. There is a lot of math in this course, but it is really amazing. You can do a Fourier Transform on a signal input (e.g. voice), process the transformed signal (sample up/down, change the frequencies), convert it back, and obtain a meaningful signal.

18-396, Signals and Systems, is the pre-req of 18-791 and I enjoyed it as much as 18-791.

TA time:

I was a grader for 18-100, Introduction to Electrical and Computer Engineering, and a grader/lab assistant for 18-220, Fundamentals of Electrical Engineering.

Summer internship:

For GE Energy... My job was to write software to control steam turbines.

Career plans:

I want to be a software engineer or an electrical engineer.

On undergraduate research:

Being involved in a research project is a very good opportunity because it is a lot more fun to learn the application, rather than just the theory behind it.

Paul Li, conducting a field test for his research.

Human detection in a video clip.