© 2019 by Hangue Park

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Gait optimization using electrical nerve stimulation (2014 Jan - 2017 Jul)

H. Park et al., Biocas 16 (in press)

Insufficient sensory feedback and reduced muscle function in a lower limb caused by peripheral nerve injury, amputation, or other neuromuscular conditions lead to locomotor deficits including asymmetric walking. In this project, I am trying to improve impaired gait (e.g. prosthetic gait) by providing artificial sensory feedback, as a form of electrical stimulus, to cutaneous nerves innervating the foot. I developed a system that monitors gait metrics and applies appropriate electrical stimulus to peripheral sensory nerves of a cat to change gait metrics in the desired direction. Based on the preliminary results, the modulation of the cutaneous sensory feedback changes several gait parameters.

Intraoral tongue drive system (2010 May - 2013 Dec)

H. Park et al., ISSCC 12

H. Park et al., TBCAS 12

People with severe physical disabilities still depend on Sip’n’Puff, head-switch, and mouth-stick, having limited functionality and accessibility although they are intuitive, robust, and price competitive. An intraoral tongue drive system (iTDS) has been developed to help disabled people to issue complex commands in more convenient way, using their voluntary tongue motion. The iTDS wirelessly transmits the magnetic sensor data, which is converted to user-defined tongue commands in real time. The iTDS provides a good mechanical stability by being firmly fixed onto the teeth (sensors maintain their relative position to the tongue), and gives the user a certain degree of privacy.

H. Park et al., ISSCC 12

H. Park et al., TBCAS 12

H. Park et al., MTT 14

H. Park et al., Sensors 14

H. Park et al., AICSP 13

I have implemented the intraoral version of the TDS (iTDS) in the form of either a palatal dental retainer to be mounted on the upper jaw or an arch-shaped dental retainer to be mounted on the buccal shelf. To meet the limited size requirement, aggressive power duty cycling has been employed. Both forms of iTDS have been tested inside the mouth to control the mouse cursor and to drive the powered wheerchair. On top of these implementations and tests of the iTDS, I compared the performance of the wireless data link among the three ISM band frequencies (27 MHz, 433.9MHz, and 2.48 GHz).

J. Kim, H. Park et al., STM 13

J. Kim, H. Park et al., JRRD 14

J. Kim, H. Park et al., TNSRE 16

External version of the TDS (eTDS), the predecessor of the iTDS, has been tested with people with tetrapledgia. People showed a fast learning curve and the eTDS outperforms the sip-n-puff (the current biggest player in the market of powered wheerchair driving by people with tetrapledgia) by three times. I prepared necessary devices and equipment for the test and participated in the human experiment.

Wireless Capsule Endoscopy System (2006 Feb - 2008 Feb)

J. Ryu et al., MTT-S 07

S. Lee et al., TBME 12

H. Park et al., EuMC 08

H. Park et al., IEICE 08, 09

K. Kim et al., TBME 12

The capsule endoscopy has been developed to substitute the colonoscopy that is unpleasant and often causes pressure, bloating or cramping in spite of the sedation. The capsule is the size and shape of a pill and contains a tiny camera. After a patient swallows the capsule, it takes pictures of the inside of the gastrointestinal tract. In this project, I developed a receiver with a high sensitivity and a wide input dynamic range to maximize the communication distance while securing the data.

Saw-less receiver for Digital RF system (2008 Feb - 2010 Apr)

H. Park et al., IEICE 10

US20100215124-A1

US20100167676-A1, US8508292-B2

I worked at Samsung electronics and had a chance to develop a saw-less receiver for Digital RF system. With increasing needs of multi-band wireless chipset with limited power and area budget, the Digital RF receiver without saw filter and without frequency down-conversion has been a challenging but attractive topic. In this project, I participated in the system design and developed a blocker-canceling LNA and a tunable High-Q active band-pass filter, to reject unnecessary signals with a high selectivity.

Industrial personal digital assistance (2001 Aug - 2004 Aug)

I worked at Bluebird Soft, a young company of industrial PDA at that time, for three years in lieu of the mandatory korean military service. From my second year at Bluebird, I was a project leader for the circuit and system design of a product named BIP1100WL, which was sold to the three top department stores in Korea (Hyundai, Shinsegae, and Lotte). This product received the industrial design award from ministry of commerce, industry, and energy and propelled the company to become a leading industrial PDA maker in Korea.