My research area is human-computer interaction(HCI). Particularly, I see a possibility of applying human sensory communication characteristics to human computer interface. For a long time in KAIST and ETRI, I have paid attention to human interface device (HID) providing haptic feedback information to user. It seemed to be successful since I received Ph.D. degree from the investigation and I have proposed several new items such as KAT series and Ubi-Pen series. I made a lot of efforts for not only designing mechanisms and devices but also finding psychophysical correlations. But now, I try to touch much more fundamental issue, that is, ‘brain’ for purer research rather than just development. Now, I work in MIT and collaborate with Touch Lab researchers.

 
Human-Computer Interface

 KAT(KAIST Artificial Touch) Series

This series are tactile feedback mouse series those have been studied from 2004 to 2007. The key idea of the tactile mouse is embedding a pin-arrayed tactile display into a conventional mouse. There have been many trials and errors during developing this. Additionally, we have continuously proposed new version of the tactile feedback mouse step by step. The final version has functions of pin-array stimulation, thermal feedback, shear motion and force feedback. Please check my publication list for details. For a movie clip, click here. This research led me to the best paper award at the 2005 Next Generation PC International Conference.

 Ubi-Pen Series

From 2006 I have designed stylus type haptic interfaces interacting with a touch screen. There are two kinds of haptic styli termed Ubi-Pen. The type I has functions of providing vibration, impact, texture and sound and it is a stand alone system including own battery and wireless communication module. The type II does not include the texture display module but it is a miniaturized version for usability. We implemented a new interaction scheme on the Windows graphical user interface based on pointer movement haptic feedback events such as clicking, drag, drop, moving and etc. In addition, a simple interactive digital sketchbook has been implemented, which is providing haptic and auditory feedback while drawing and touching objects. We also implemented a tactile image display method on a touch screen with the wUbi-Pen and a simple fitting puzzle utilizing haptic feedback events. Please check my publication list for details. For a movie clip, click here or here. Hopefully, this system will be commercialized by a mobile device company sooner or later. This research led me the best paper award at the 2007 Korea HCI Conference.

 
Brain-Computer/Machine Interface

MEG based Brain-Machine Interface

In 2008, I just start brain computer/machine interface research. Previous brain-computer researches have been mainly focused brainwave like EEG. They have seemed successful but they usually produce binary response for several channels. For more accurate analysis of brain activity, I pay attention to MEG(Magnetoencephalography). MEG is an imaging technique used to measure the magnetic fields caused by electrical activity in the brain via extremely sensitive devices such as Super-conducting QUantum Interference Device(SQUID). I am trying to measure brain activities during human motion and this will be applied to continuous motion control of machines such as robots or computers. This approach led me to the encouragement prize at the 2007 Korea Next Generation Computing Contest. Please check my publication list for details.

 
Psychophysical Study on Sensory Perception

 Compact Broadband Tactile Display

Haptics study should be done with psychological analysis as well as design of a system. Haptics is a perfect interdisciplinary research area. Especially, we have to know how a human feels tactile stimuli in advance before developing any haptic interface. In tactile display area, human perception study becomes much more important. So, I have developed a compact broadband tactile display as a test-bed. For a movie clip, click here. And I observed human spatial acuities, elements of perceived roughness, vibrational threshold and sensation levels. Please check my publication list for details. The subjects for my experiments were visually impaired people, children and old people as well as young and healthy people.

 
Medical Applications

 Realistic Medical Simulators with Haptic Feedback

Interactive medical simulator was the main topic of my M.S. Thesis. From 2000 to 2001, I have tried to develop a spine biopsy simulator with 3D visual feedback and force feedback. I suggested a tissue penetrating model for the realistic simulation of needle insertion. For a movie clip, click here. This research led me to the best student paper award at the 2000 Korean Biological and Medical Engineering Spring Conference.

From 2006 to 2007, adding tactile feedback function to force feedback simulator has been investigate. A small tactile display with 5x6 pin array was attached to the PHANToM and we proposed a methodology to simulate palpation process to detect doubtable portion inside the human body. Please check my publication list for details.

Standardization

In these days, there are several products providing haptic feedback to users. For example, Nintendo’s WII, Sony’s PlayStation II and Samsung’s haptic phone adopt haptic feedback function. However, there is no international standard for haptic interface or interaction. I am a member representing Korea in ISO/TC159/SC4. In Korea, I have submitted several standard documents for TTA. And I am collaborating with national bodies at the ISO meeting for developing ISO 9241-900 series. I am a co-editor of ISO 9240-910. In 2007, I received the Award of the Minister of Information and Communication in outstanding paper contest for standardization of Information and communication.