Decreased Maximal Tongue Protrusion Length May Predict the Presence of Dysphagia in Stroke Patients

Hyunchul Cho,Jeong Se Noh,Junwon Park,Changwook Park,No Dam Park,Jun Young Ahn,Ji Woong Park,최윤희,천성민 대한재활의학회 2021 Annals of Rehabilitation Medicine Vol.45 No.6

Objective To investigate the relationship between maximal tongue protrusion length (MTPL) and dysphagia in post-stroke patients.Methods Free tongue length (FTL) was measured using the quick tongue-tie assessment tool and MTPL was measured using a transparent plastic ruler in 47 post-stroke patients. The MTPL-to-FTL (RMF) ratio was calculated. Swallowing function in all patients was evaluated via videofluoroscopic swallowing study (VFSS), Penetration-Aspiration Scale (PAS), Functional Oral Intake Scale (FOIS), and Videofluoroscopic Dysphagia Scale (VDS).Results The MTPL and RMF values were significantly higher in the non-aspirator group than in the aspirator group (MTPL, p=0.0049; RMF, p<0.001). MTPL and RMF showed significant correlations with PAS, FOIS and VDS scores. The cut-off value in RMF for the prediction of aspiration was 1.56, with a sensitivity of 84% and a specificity of 86%.Conclusion There is a relationship between MTPL and dysphagia in post-stroke patients. MTPL and RMF can be useful for detecting aspiration in post-stroke patients.

Wireless Biomimetic Swimming Mini-Robots Using Electro-Magnetic Actuation (EMA) System

Hyunchul Choi,Semi Jeong,Cheong Lee,Gwangjun Go,Kiduk Kwon,Seong Young Ko,Jong-Oh Park,Sukho Park 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10

For the actuation of mini-robots, various types of electromagnetic based actuation (EMA) methods were proposed. Compared with conventional actuation system using electric motor, EMA system has many advantages for the wireless actuation of mini-robots. This paper introduces our proposed biomimetic swimming mini-robots such as tadpole robot and jellyfish robot. The developed biomimetic swimming mini-robots could be driven by an external alternating magnet field using three pairs of Helmholtz coils. The swimming mini-robots consist of a buoyant swimming mini-robot body, permanent magnets, and fins. Especially, the tadpole swimming mini-robot has a single fin which is directly linked to the permanent magnet and the jellyfish swimming mini-robot has multiple fins which have a permanent magnet at the end of fins. The external alternating magnetic field from three pairs of Helmholtz coils could generate the propulsion and steering force of the tadpole mini-robot and the jellyfish mini-robot in 2- and 3-dimensional (D) space.

Electromagnetic induction energy harvester for high-speed railroad applications

Park, Hyunchul,Kim, Jaehoon SPRINGER 2016 INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND Vol.3 No.1

Biomimetic Swimming Mini-Robots Using Electro-Magnetic Actuation (EMA) System

Hyunchul Choi,Semi Jeong,Cheong Lee,Youngho Ko,Seong Young Ko,Jong-Oh Park,Sukho Park 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

For the actuation of mini-robots, electromagnetic based actuation (EMA) methods were proposed. EMA system has many advantages for the wireless actuation of mini-robots. This paper introduces our proposed biomimetic swimming mini-robots such as tadpole robot and jellyfish robot. The biomimetic swimming mini-robots could be driven by an external alternating magnet field using three pairs of Helmholtz coils. The swimming mini-robots consist of a buoyant robot body, permanent magnets, and fins. Especially, the tadpole mini-robot has a single fin which is directly linked to the permanent magnet and the jellyfish mini-robot has multiple fins which have a permanent magnet at the end of fin. The external alternating magnetic field from three pairs of Helmholtz coils could generate the propulsion and steering force of the tadpole mini-robot and the jellyfish mini-robot in 2- and 3-dimensional (-D) space. Firstly, we demonstrated the fabrications of the EMA coil system and the mini-robots. Secondly, we summarized the locomotive algorithms of the mini-robots using EMA. Thirdly, we setup the control system for the EMA driven mini-robots, which consists of EMA coils, dual cameras, controller, power amplifier, and conventional joystick. Through various experiments, we evaluated the locomotion algorithms the swimming mini-robots using EMA system. Finally, we demonstrated the performances of the swimming mini-robots in 2-D and 3-D space.

<i>In Operando</i> Monitoring of the Pore Dynamics in Ordered Mesoporous Electrode Materials by Small Angle X-ray Scattering

Park, Gwi Ok,Yoon, Jeongbae,Park, Eunjun,Park, Su Bin,Kim, Hyunchul,Kim, Kyoung Ho,Jin, Xing,Shin, Tae Joo,Kim, Hansu,Yoon, Won-Sub,Kim, Ji Man American Chemical Society 2015 ACS NANO Vol.9 No.5

<P>To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an <I>in operando</I> probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angel X-ray scattering (SAXS) technique. <I>In operando</I> SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteries.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-5/acsnano.5b01378/production/images/medium/nn-2015-013783_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b01378'>ACS Electronic Supporting Info</A></P>

In situ synchrotron wide-angle X-ray scattering study on rapid lithiation of graphite anode via direct contact method for Li-ion capacitors

Park, Hyunchul,Kim, Minho,Xu, Fan,Jung, Cheolsoo,Hong, Soon Man,Koo, Chong Min Elsevier 2015 Journal of Power Sources Vol.283 No.-

<P><B>Abstract</B></P> <P>Lithium pre-doping of graphite anode is a key process to achieve high energy density lithium-ion capacitor. In this study, in situ synchrotron wide-angle X-ray scattering examinations directly revealed that the direct contact (DC) method, simply achieved through direct physical contact between graphite electrode and sacrificial lithium metal in electrolyte, provides much faster phase transformation from stage 1ʹ to stage 1 than conventional electronic charger (EC) and external short circuit (ESC) methods at the same doping time level. The observations indicate that DC method achieves faster pre-lithiation rate of graphite electrode than EC and ESC processes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase transformation of graphite was characterized by in situ X-ray scattering. </LI> <LI> Direct contact between graphite and lithium metal leads fast lithiation. </LI> <LI> The direct contact method is a robust pre-doping process without any safety issues. </LI> <LI> The study provides an alternative pre-doping method for Li-ion capacitors. </LI> </UL> </P>

High-Intensity Focused Ultrasound for the Treatment of Wrinkles and Skin Laxity in Seven Different Facial Areas

( Hyunchul Park ),( Eunjin Kim ),( Jeongeun Kim ),( Youngsuck Ro ),( Jooyeon Ko ) 대한피부과학회 2015 Annals of Dermatology Vol.27 No.6

Background: High-intensity focused ultrasound (HIFU) treatment has recently emerged in response to the increasing demand for noninvasive procedures for skin lifting and tightening. Objective: This study was aimed at evaluating the clinical efficacy of and patient satisfaction with HIFU treatment for wrinkles and laxity in seven different areas of the face in Asian skin. Methods: Twenty Korean patients with facial wrinkle and laxity were analyzed after a single session of HIFU treatment. Two independent, blinded clinicians evaluated the clinical improvement in seven areas of the face by comparison of standardized photographs obtained before, and at 3 and 6 months after treatment. Assessment of subjective satisfaction and adverse effects of treatment were done by using questionnaires. Results: The physicians` evaluation and patients` satisfaction with the clinical effects of HIFU in each area were similar regardless of the number of treatment shots. The jawline, cheek, and perioral areas were the sites where HIFU was most effective, in decreasing order. The adverse effects included erythema and swelling in six cases, and purpura and bruising in two cases. However, the adverse effects were mild and transient. Conclusion: HIFU could be a safe, effective, and noninvasive procedure that can be used to improve facial wrinkles and skin laxity in Asian skin. It is particularly effective for clinical improvement in the jawline, cheek, and perioral areas. (Ann Dermatol 27(6) 688∼693, 2015)

Formation of highly ordered discrete wrinkle array on PDMS surface via stenciling process

Hyunchul Park,Soon Man Hong,Jun Pyo Hong,Chong Min Koo 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

3-D Locomotive and Drilling Microrobot Using Novel Stationary EMA System

Hyunchul Choi,Kyoungrae Cha,Semi Jeong,Jong-oh Park,Sukho Park IEEE 2013 IEEE/ASME transactions on mechatronics Vol.18 No.3

<P>For 3-D locomotion and drilling of a microrobot, we proposed an electromagnetic actuation (EMA) system consisting of three pairs of stationary Helmholtz coils, a pair of stationary Maxwell coils, and a pair of rotating Maxwell coils in the previous research . However, this system could have limited medical applications because of the pair of rotational Maxwell coils. In this paper, we propose a new EMA system with three pairs of stationary Helmholtz coils, a pair of stationary Maxwell coils, and a new locomotive mechanism for the same 3-D locomotion and drilling of the microrobot as achieved by the previously proposed EMA system. For the performance evaluation of the proposed EMA system, we perform a 3-D locomotion and drilling test in a blood vessel phantom. In addition, the two EMA systems are compared to show that the newly proposed EMA system has 440% wider working space and 49% less power consumption than the previous EMA system.</P>

PANDA와 VNC에 기반한 U-Kiosk 구현

석현철(Hyunchul Seok),박기웅(Ki-Woong Park),임상석(Sang Seok Lim),박규호(Kyu Ho Park) 한국정보과학회 2006 한국정보과학회 학술발표논문집 Vol.33 No.2A

휴대용 단말기의 보급과 인터넷 및 무선 네트워크의 발달로 사용자들이 사용하는 개별 장치들이 보편화되어 있으며, 이들을 서로 유기적으로 엮은 서비스가 등장하고 있다. 본 논문에서는 이러한 서비스의 한 종류로 U-Kiosk의 개념을 소개한다. U-Kiosk는 Kiosk 단말장치나 공용 PC를 사용자 개인의 PC처럼 사용할 수 있도록 하는 서비스로서 유무선 네트워크를 이용하여 개인의 모바일 장치나 개인 PC로 접속을 하여 이들의 리소스를 직접 제어할 수 있는 기능을 제공한다. 이것을 실현하기 위한 방안으로 본 논문에서는 공용 PC에서 개인 PC의 바탕화면 설정을 포함해 모든 자원을 직접 사용할 수 있도록 하는 부분을 구현하고 설명을 하였으며, 인증 과정에서 사용자의 개입을 최소한으로 줄이는 방법에 대해서 소개한다. 이를 위하여 초소형 보안 단말기의 PANDA를 사용하였으며, Zigbee 통신을 사용하여 사용자의 위치정보를 파악하여 자동으로 인증을 하도록 하는 Transient Authentication의 개념을 도입하였다. 두 컴퓨터 간의 원격 접속을 위해서는 VNC를 이용하여 구현하였으며, 사용자가 공용 PC로부터 일정 거리 안에 있을 경우, 자동으로 원격 접속이 이루어지고, 공용 PC로부터 멀어질 경우 자동으로 접속이 종료되도록 구현하였다. 이를 기반으로 제안하는 U-Kiosk의 개념에 맞는 테스트 베드를 구축 하였다. 이는 UFC Project의 일부로서 차후 완벽한 인증 인프라를 구축하여 보다 안정적이고 사용하기 편리한 U-Kiosk의 구현에 초석이 될 것이다.