2023 석사 논문상 후보자 : 최수진(Soojin Choi)

최수진(Soojin Choi) 한국컴퓨터그래픽스학회 2023 한국컴퓨터그래픽스학회 학술대회 Vol.2023 No.7

Thrust enhancement via gel-type liquid confinement of laser ablation of solid metal propellant

Choi, Soojin,Han, Tae-hee,Gojani, Ardian B.,Yoh, Jack J. Springer-Verlag 2010 APPLIED PHYSICS A MATERIALS SCIENCE AND PROCESSING Vol.98 No.1

Feasibility of Robot-Assisted Gait Training with an End-Effector Type Device for Various Neurologic Disorders

Choi Soojin,Kim Seong Woo,Jeon Ha Ra,Lee June Sung,Kim Dong Yeong,이장우 대한뇌신경재활학회 2020 뇌신경재활 Vol.13 No.1

Robots are being used to assist the recovery of walking ability for patients with neurologic disorders. This study aimed to evaluate the feasibility and functional improvement of training with robot-assisted gait training (RAGT) using the Morning Walk®, an end-effector type robot using footplates and saddle seat support. A total of 189 individuals (65.1% men, 34.9% women; mean age, 53.2 years; age range: 5–87 years) with brain lesions, spinal cord injuries, Parkinson’s disease, peripheral neuropathies, and pediatric patients were involved in this retrospectively registered clinical trial. Each participant performed 30 minutes of RAGT, five times a week, for a total of 24 sessions. Failure was defined as an inability to complete all 24 sessions, and the reasons for discontinuation were analyzed. Parameters of Medical Research Council scales and Functional Ambulation Categories were analyzed before and after RAGT training. Among the 189 patients, 22 (11.6%) failed to complete the RAGT. The reasons included decreased cooperation, musculoskeletal pain, saddle seat discomfort, excessive body-weight support, joint spasticity or restricted joint motion, urinary incontinence from an indwelling urinary catheter, and fatigue. Comparison between the pre- and post-training motor and ambulatory functions showed significant improvement. The result of the study indicates that the Morning Walk® is feasible and safe and useful for functional improvement in patients with various neurologic disorders

Accuracy Enhancement of Raman Spectroscopy Using Complementary Laser-Induced Breakdown Spectroscopy (LIBS) with Geologically Mixed Samples

Choi, Soojin,Kim, Dongyoung,Yang, Junho,Yoh, Jack J. Society for Applied Spectroscopy 2017 Applied spectroscopy Vol.71 No.4

<P>Quantitative Raman analysis was carried out with geologically mixed samples that have various matrices. In order to compensate the matrix effect in Raman shift, laser-induced breakdown spectroscopy (LIBS) analysis was performed. Raman spectroscopy revealed the geological materials contained in the mixed samples. However, the analysis of a mixture containing different matrices was inaccurate due to the weak signal of the Raman shift, interference, and the strong matrix effect. On the other hand, the LIBS quantitative analysis of atomic carbon and calcium in mixed samples showed high accuracy. In the case of the calcite and gypsum mixture, the coefficient of determination of atomic carbon using LIBS was 0.99, while the signal using Raman was less than 0.9. Therefore, the geological composition of the mixed samples is first obtained using Raman and the LIBS-based quantitative analysis is then applied to the Raman outcome in order to construct highly accurate univariate calibration curves. The study also focuses on a method to overcome matrix effects through the two complementary spectroscopic techniques of Raman spectroscopy and LIBS.</P>

Comparison of Outcomes after Wavefront-optimized and Topography-guided Transepithelial Photorefractive Keratectomy

SooJin Kim,Sungjin Na,Sangkyung Choi,Sung-Ho Choi 대한안과학회 2024 Korean Journal of Ophthalmology Vol.38 No.4

Dynamic characteristics of a flagellar motor protein analyzed using an elastic network model

Choi, Moon-ki,Jo, Soojin,Lee, Byung Ho,Kim, Min Hyeok,Choi, Jae Boong,Kim, Kyunghoon,Kim, Moon Ki Elsevier 2017 Journal of molecular graphics & modelling Vol.78 No.-

<P><B>Abstract</B></P> <P>At the base of a flagellar motor, its rotational direction and speed are regulated by the interaction between rotor and stator proteins. A switching event occurs when the cytoplasmic rotor protein, called C-ring, changes its conformation in response to binding of the CheY signal protein. The C-ring structure consists of FliG, FliM, and FliN proteins and its conformational changes in FliM and FliG including Helix<SUB>MC</SUB> play an important role in switching the motor direction. Therefore, clarifying their dynamic properties as well as conformational changes is a key to understanding the switching mechanism of the motor protein. In this study, to elucidate dynamic characteristics of the C-ring structure, both harmonic (intrinsic vibration) and anharmonic (transition pathway) analyses are conducted by using the symmetry-constrained elastic network model. As a result, the first three normal modes successfully capture the essence of transition pathway from wild type to CW-biased state. Their cumulative square overlap value reaches up to 0.842. Remarkably, it is also noted from the transition pathway that the cascade of interactions from the signal protein to FliM to FliG, highlighted by the major mode shapes from the first three normal modes, induces the reorientation (∼100° rotation of FliG<SUB>C5</SUB>) of FliG C-terminal that directly interacts with the stator protein. Presumably, the rotational direction of the motor protein is switched by this substantial change in the stator-rotor interaction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dynamic characteristics of cytoplasmic ring are investigated using normal mode analysis based on elastic network model. </LI> <LI> Transition of FliG protein from wild type to CW-biased provides insights into the structural change switching event. </LI> <LI> Structural dynamics of motor protein implies that the reorientation of important domains makes rotation of motor effective. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Internet use as a Leisure Pastime : Older Adults' Subjective Well-Being and its Correlates

Soojin Choi,Xinran Y. Lehto 한국관광학회 2009 International Journal of Tourism Sciences Vol.9 No.3

This study examines older adult's subjective well-being (SWB) as a measure of Quality of Life (QOL) and its relationship with other SWB correlates. It investigates whether the Internet plays a significant role in assessing the life quality of older adults. It is proposed that spending time online helps fulfill leisure, interaction with the outer world, and socializing needs of older adults, and thereby promotes physical and mental health in older age. The interplay of these factors was tested through a structural equation model using secondary data of a nationally representative sample of older individuals over 50 years old in the U.S. The results show that older adults' interactional activities on the Internet through information seeking and communication have positive associations with all three SWB correlates and consequently exert impacts on their subjective health and subjective well-being. While considerable research has examined the structure of SWB, or the impact of leisure activities and social interaction on SWB, this study expands the SWB framework by including not only leisure and social interaction variables but also the Internet influences on them.

Chorea Hyperglycemia Basal Ganglia Syndrome in a Young Patient with Type 1 Diabetes Mellitus: a Case Report

Choi Soojin,Rhee Seung Yeon,김형섭 대한뇌신경재활학회 2020 뇌신경재활 Vol.13 No.2

Chorea hyperglycemia basal ganglia (CHBG) syndrome is an uncommon manifestation of diabetes seen in patients with poor glycemic control. It is characterized by sudden onset of chorea with characteristic hyperintensities of the basal ganglia on brain magnetic resonance imaging. We report a case of a 31-year-old female patient with a history of type 1 diabetes mellitus, renal failure, and hypertension, who presented with acute symptoms of chorea involving both the upper and lower limbs with facial and cervical dystonia. Magnetic resonance imaging revealed bilateral hyperintensities of the globus pallidus and putamen. Control of blood glucose levels led to resolution of the choreic movements. In addition, follow-up magnetic resonance imaging studies revealed improvement in the hyperintensities of the basal ganglia bilaterally.

Cost-Effective Scalable Synthesis of Mesoporous Germanium Particles <i>via</i> a Redox-Transmetalation Reaction for High-Performance Energy Storage Devices

Choi, Sinho,Kim, Jieun,Choi, Nam-Soon,Kim, Min Gyu,Park, Soojin American Chemical Society 2015 ACS NANO Vol.9 No.2

<P>Nanostructured germanium is a promising material for high-performance energy storage devices. However, synthesizing it in a cost-effective and simple manner on a large scale remains a significant challenge. Herein, we report a redox-transmetalation reaction-based route for the large-scale synthesis of mesoporous germanium particles from germanium oxide at temperatures of 420–600 °C. We could confirm that a unique redox-transmetalation reaction occurs between Zn<SUP>0</SUP> and Ge<SUP>4+</SUP> at approximately 420 °C using temperature-dependent <I>in situ</I> X-ray absorption fine structure analysis. This reaction has several advantages, which include (i) the successful synthesis of germanium particles at a low temperature (∼450 °C), (ii) the accommodation of large volume changes, owing to the mesoporous structure of the germanium particles, and (iii) the ability to synthesize the particles in a cost-effective and scalable manner, as inexpensive metal oxides are used as the starting materials. The optimized mesoporous germanium anode exhibits a reversible capacity of ∼1400 mA h g<SUP>–1</SUP> after 300 cycles at a rate of 0.5 C (corresponding to the capacity retention of 99.5%), as well as stable cycling in a full cell containing a LiCoO<SUB>2</SUB> cathode with a high energy density (charge capacity = 286.62 mA h cm<SUP>–3</SUP>).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-2/acsnano.5b00389/production/images/medium/nn-2015-00389h_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b00389'>ACS Electronic Supporting Info</A></P>

터치스크린의 버튼 색과 입력 시간에 따른 행동유도성 연구

최수진(SooJin Choi),박영경(YungKyung Park) 한국색채학회 2020 한국색채학회 학술대회 Vol.2020 No.11

사용자의 행동을 유도한다는 뜻의 아포던스(Affordance)는 디자인에서 사용성 개선을 위한 도구로 쓰이며, 특히 색채의 행동 유도성은 직관적인 행동을 도와준다. 직관적이고 신속한 행동을 유도해야 하는 터치스크린 환경에서 사용성을 높이기 위해 본 연구는 터치스크린의 버튼 색에 따른 입력 시간을 측정하여 ‘신속하게 누르게 만드는’ 버튼 색을 도출해내고자 하였다. PCCS에서 추출한 18개의 색 가운데 빈도수가 높은 버튼 색과 신속하게 눌린 버튼 색을 비교하는 방식으로 사용성을 측정하였다. 응답 결과, 가장 빈도수가 높게 선택된 버튼은 Light, Vivid톤으로 톤의 영향이 두드러지게 나타난 반면, 가장 시간이 단축된 버튼은 Blue, White, Black으로 주로 무채색이 신속하게 눌렸다. 버튼 색의 빈도수와 입력 시간을 비교해보면, 공통점으로 고명도 White는 빈도수뿐 만 아니라 입력 시간에서도 매우 높은 행동 유도성을 보였다. 차이점은 빈도수의 경우 톤의 영향이 컸지만, 입력 시간의 경우 색상에 대한 영향이 나타났으며 저명도의 색이 상대적으로 빠른 행동 유도성을 보였다. 두 측정 간의 차이를 보였으므로 터치스크린의 사용성 연구를 위해 입력 시간에 대한 측정이 유의미함을 확인하였다.