Research

Cloth animation with impulse based collision response (2012)

This is part of the development of my physics-based computer graphics simulation library, named Ditto. Once it gets to a release-ready point, I will likely make Ditto available on SourceForge or similar.

In this project, cloths are simulated with Finite Volume Method. Collisions with rigid body and self/other cloth objects are solved robustly with velocity impulses.

Demo: Full

Demo: High Resolution Test

Simulation of elastic solids with efficient self-collision handling (2011)

Developed a highly efficient hybrid Eulerian/Lagrangian approach for self-collision and body collisions.

It is proved that with the help of a Navier-Stokes solver, the solid can avoid a large amount of collisions without using any expensive collision detection/ response function calls. Simulation results show that with our method, self collisions can be solved in real time for a large amount of simulations.

This is my Thesis my a MS in CS degree. PDF available upon request.

Demo: Blowing

FEM Simulation of Elastic Objects (2011)

Major applications: Special Effects for movies, realistic graphics for 3D animations & games Finite Element Method for solving Possion equations. Numerical methods.

I worked with Craig Schroeder and developed an extremely robust penalty force based method for self collision.

2D_Demo

Video Contour Tracking Software Development (Spring 2011)

Image segmentation is one of the most popular topics in computer vision. Active contours is one of the most popular techniques in image segmentation.

Here we developed a software that could be used to track object contour in a video precisely. This tool has many applications in biology and medical imaging.

Artificial Life (Winter 2011)

We built an artificial millepede with perception systems completely from scratch, using OpenGL and C++. The 3D Bio-Mechanical model is built with Spring-Damper system and Rigid-Body dynamics. Under different initial states, the motion pattern of the millepedes legs will magically converge to a wavelike pattern. The perception is built with virtual antennas so that the millepede could avoid obstacles and search for food. Genetic algorithm is used in the simulation of millepede evolution. The species group get optimized through auto-optimization of leg moving pattern and the evolving of gene sequences.

Here we developed a software that could be used to track object contour in a video precisely. This tool has many applications in biology and medical imaging.

Simulating sensors and steering behaviors of Braitenberg vehicles (Winter 2011)

I have simulated a Braitenberg vehicle (an agent that can autonomously move around) in a 3d virtual world. It has primitive sensors(measuring some stimulus at a point) and wheels(each driven by its own motor) that function as actuators or effectors.

I have integrated the agent simualtion system into the library that I'm developing. The APIs can be easily used for simulating more complicated behaviors such as artificial animals or human beings.

Mass - Spring - Damper System Simulator

In artificial Millepede project, spring damper is specially created for the body sections of a millepede. I realize that I am going to use mass-spring-damper system quite often in the future. For convenience, I wrote a templete for this system so that I could use it to design any deformable model.

Ray-Tracer for photorealistic graphics generation (Winter 2011)

Ray tracing is a technique for generating an image by tracing the path of light through pixels in an image plane and simulating the effects of its encounters with virtual objects. The technique is capable of producing a very high degree of visual realism, usually higher than that of typical scanline rendering methods, but at a greater computational cost. It is capable of simulating a wide variety of optical effects, such as reflection and refraction, scattering, and chromatic aberration.

Computer Animation: Self - Controlling Little Car (2011)

This animation is to demonstrate a car going straight, steeling around and jump over a river under gravity simulation. The sky, ground and the car are taxture mapped objects. The car-like vehicle is modeled with automobile kinetics method. Therefore, given the following parameters: wheel rotation angle, wheel rotation speed, e.t.c., it will automaticly generate the future position for the car.

This animation is also a basic demo for a primitive Braitenberg Vehicles. By adding artificial intelligence system to the car, it could intelligently avoid obstacles and look for targets.

demo

Hunting Serial Crimials With Georaphic Profiling Method (Spring 2010)

Serial killers is an very interesting topic to study in statistics, criminology and psychology. Scientific methods for hunting serial criminals are developing very fast. Sometimes computer programs work better than cops!

Our approaches are:
(1) Statistical Scheme: We examinate both Rossmo and O'Leary 's empirical distribution law. And use maximum likelood method to get the best parameters.
(2) Random Walk simulation: We propose this scheme independently. We feel this kinetic model could better simulate the criminal's activity.

Mapping Mayhem: On the Road of Hunting Serial Criminals

Plasma Physics - Relativity - Inertia Confinement Fusion (2010)

Imagine what will happen if Inertia Confinement Fusion (ICF) succeeds one day: The whole world will no longer face any energy problem at all! Various research projects are being done for this gole all over the world. In order to detect the temperature and density of plasmas in the little hot fusion target, a technique called Thomson Scattering could be widely used.

Relativistic correction of $(v/c)^{2}$ to the collective Thomson scattering Jian Zheng, Chenfanfu Jiang, Bin Zhao | November 11, 2010 |American Physical Society (APS meeting). Abstract ID: BAPS.2010.DPP.UP9.10 http://meetings.aps.org/Meeting/DPP10/Event/131636

Collective Thomson scattering with inclusion of relativistic correction of (v=c)2 is theoretically investigated. The correction is rather small when inferring plasma parameters from the spectra off thermal electron plasma waves in the plasmas. Since the full formula of the corrected result is rather complicated, a simplified one is derived for the sake of practical use, which agrees well with the un-simplified one.