Lighting:
Advanced lighting such as HDR environment lighting, shadowing, global illumination and subsurface scattering is my main research topic. "A GPU-Based Light Hierarchy for Real-Time Approximate Illumination" and "An Effcient Shadow Texture Algorithm with Shadow Maps" are related academic papers of mine. 
  Currently, I'm developing a real-time lighting engine such as the Enlighten, as a personal project.

Appearance Modeling:
Another research topic is appearance modeling, which develops new models and algorithms to represent appearance of real materials such as human and creature skin, and rusty metal. "Real-Time Subsurface Scattering using Shadow Maps" will be appeared in ShaderX7.

Next-Generation 3D Graphics with GPUs:
I'm also interested in next-generation 3D graphics systems with GPU programming such as Gelato and Unreal Engine. My "Pyramidal Displacement Mapping (PDM)" is a cool technique for such systems. I'm currently developing a next-generation 3D engine at INNOACE Co., Ltd.