VisTA : an integrated vision Tri-architecture system

Sunwoo, Myung Hoon Graduate School of The University of Texas at Aust 1990 국내박사

The Fabrication, Actuation, and Application of Magnetically Actuated Self-Assembled Artificial Cilia

Sunwoo Sohn DGIST 2022 국내석사

Implantable sensors for measuring electrophysiological signal from adrenal gland

Sunwoo, Sunghyuk Sungkyunkwan university 2018 국내석사

We demonstrated an implantable sensor which can detect electrophysiological signal (EPS) from adrenal gland. The EPS from the adrenal gland has significant relationship with cellular activities of adrenal zona fasciculata (AZF) cells responding to cortisol release. Thus, we could expect cortisol level by EPS from adrenal gland. The implantable sensor that is electrophysiological probe was designed to have arrowheaded tip that can fixed in the adrenal gland. The probe also has soft nature with biocompatible, ultrathin (~7 μm), flexible polymeric materials on thick (~250 μm) and rigid implantation shuttle which can be removed by mechanical fracture when implanted. We fabricated the probe with photolithography process that commonly used for fabricating flexible neural implants. The probe and shuttle was aligned and implanted to the adrenal gland of anesthetized rat, then the shuttle part was removed so that the only thin, biocompatible part remained in the tissue. This minimal invasive implantation technique enabled biocompatible and longitudinal implantation with more than three months of probe lifetime in the body. We succeed to collect the action potential-like spike of AZF cells of living rat, respond to stress stimulation, for a long time. Moreover, we manipulated the release of cortisol hormone with the electric stimulation to living animal with various open-field tests.

Rainfall-runoff modeling using satellite and reanalysis soil moisture products

Sunwoo, Wooyeon 성균관대학교 수자원전문대학원 2021 국내박사

In this study, remotely sensed soil moisture products were used as input datasets to the rainfall-runoff mode and parameter optimization techniques were applied to improve accuracy of runoff estimation. In the first process, application of datasets was confirmed by indicating a high inverse correlation between remotely sensed soil moisture and the maximum potential retention of soil. After assessing the correlation between remotely sensed soil moisture and ground soil moisture and variability due to rainfall, input datasets including soil moisture were constructed. In the second process. In the second process, runoff was calculated by establishing the NRCS-CNsm model, which calculated the CN from satellite soil moisture in the Natural Resources Conservation Service Curve Number (NRCS-CN) model. Compared to conventional NRCS-CN, application of the satellites Surface Soil Moisture (SSM) and Surface Moisture Index (SWI) resulted in reduced estimation error of the runoff and improved accuracy. Thus, application of remotely sensed soil moisture can be seen as leading to improved accuracy of input data and runoff estimation. Furthermore, estimated runoff values from the PDMsm model, which applied reanalysis soil moisture and evapotranspiration products as input datasets from the Probability Distributed Model (PDM), have shown a slight improvement over existing model. However, when the rainfall was less than 20 mm, the error rate averaged 92%. PDMsm model tends to be sensitive to rainfall variability because it reflects soil moisture. It was also found useful for estimating low flow when optimizing parameters with the Partial Swarm Optimization (PSO). Finally, the Leave-One-Out Cross-Validation (LOOCV) and skill score techniques were applied to verify two proposed models to ungauged region. NRCS-CNsm showed no significant change, and PDMsm has increased accuracy 67.7% compared to existing model when crossing space. In this study, the proposed rainfall-runoff models showed improvement of accuracy for runoff estimation and availability of remotely sensed soil moisture. It can also be used to estimate the total runoff of ungauged region with continuous rainfall-runoff using historical data derived from remotely sensed datasets. 본 연구에서는 강우 유출 추정의 정확도 향상을 위해서 원격 토양수분을 강우 유출 모형의 입력 자료로 활용하고, 매개변수 최적화 기법을 유출 모형에 적용하여 유출을 산정하였다. 먼저, 원격 토양수분의 활용 가능성 평가를 통해 자료를 구성한 후, 강우유출 모형의 입력자료로 활용하여 유출을 추정하였다. 앞서 수립된 유출 모형을 미계측 유역에 적용하여 활용가능성을 검토하였다. 첫 번째 과정에서 원격 토양수분 자료와 토양의 최대잠재보유수량이 높은 역상관관계를 나타내 자료의 활용성을 확인하였고, 원격 토양수분과 지점 토양수분의 상관성, 강우에 따른 변동성을 평가한 후에 토양수분을 포함한 입력 자료를 구성하였다. 두 번째 과정에서는 Natural Resources Conservation Service Curve Number (NRCS-CN) 강우 유출 모형의 CN 을 위성 토양수분으로 계산한 NRCS-CNsm 모델을 수립하여 유출고를 산정하였다. 기존의 NRCS-CN 모델과 비교했을 때 위성의 지표토양수분(SSM)와 지표수분지수(SWI)를 적용한 경우에 유출고의 추정 오차가 감소하고 정확도가 개선되는 결과를 나타냈다. 따라서 원격 토양수분을 활용함으로써 강유유출 모형의 입력자료 및 유출고 산정 정확도 개선이 가능한 것을 확인할 수 있다. 또한 The probability distributed model (PDM)의 입력 자료로 재분석 토양수분과 증발산 자료를 활용한 PDMsm 모형으로 추정된 유출값을 기존 모델의 결과와 비교했을 때 미세한 정확도 개선을 나타냈으나, 강우량이 20 mm 미만일 때 평균 92%의 높은 오차감소율을 나타냈다. 따라서 본 연구에서 제안된 PDMsm 모형은 토양의 수분상태를 반영하기 때문에 강우의 변동성에 민감한 경향이 있으며, Partial swarm optimization 기법으로 매개변수 최적화를 했을 때 저유량 예측에 유용함을 확인하였다. 마지막으로 미계측 유역에 대한 적용성을 검토하기 위해 NRCS-CNsm, PDMsm 에 Leave-One-Out Cross-Validation (LOOCV)기법과 skill score 기법을 적용하였다. NRCS-CNsm 모델은 정확도에 큰 변화가 없었으며, PDMsm 의 경우, 공간 교차 시 예측 정확도가 기존 모델보다 67.7% 증가한 것으로 나타났으며, 강우-유출 이상치가 발생했을 때 유출을 과소 추정하고 활용도가 감소하는 것으로 나타나 이상치에 대한 전처리 과정, 또는 다른 방향의 개선이 필요하다. 하지만 본 연구를 통해 제안된 유출 추정 방법은 검증과정과 도출된 결과를 통해 원격 토양수분의 활용성과 유출량 산출의 정확도의 향상을 나타냈다. 또한 원격 방법으로 산출된 과거의 기상수문 데이터를 이용한 연속적인 강우 유출 모의로 미계측 유역의 총유출량을 추정하는데 활용될 수 있다.

(An)experimental study on the effect of the additives on soluble calmodulin levels in the medullary tissues of nephric organ of normal adult Guinea pig

Sunwoo, Kyung-Hee Kyung Hee Univ. 1988 국내석사

Quantitative Analysis of Tissue Clearing Based on Optical Coherence Tomography and Magnetic Resonance Imaging

Sunwoo Jung Graduate School of UNIST 2017 국내석사

In the past decades, many optical imaging modalities have played a key role to understand how neurons connect and mediate their function. Especially, deep brain imaging has been crucial in neural anatomy research by providing brain-wide structural information. Although the optical imaging renders the high resolution brain image, it has restriction to perform the deep brain imaging due to inherent scattering problem of light. To enhance the imaging depth, many optical imaging modalities have combined with serial sectioning. As name suggests, serial sectioning solves the penetration depth problem by successively sectioning the tissue and imaging the remained tissue. Although serial sectioning techniques enable us to visualize whole brain, these techniques still have remained challenging in terms of labor intensive technique as well as tissue damages due to physical sectioning. Therefore, it is very demanding the new approach for whole brain imaging while preserving the intact brain. In recent years, development of tissue clearing which renders biological sample transparent proposes a solution to solve the penetration depth issue. It reduces the problematic light scattering and thus extends the limited penetration depth by either matching the refractive index or removing the lipid. As mentioned above, many researchers have developed various optical clearing agents such as Scale, 3DISCO, SeeDB, CLARITY, and ClearT. Scale and CLARITY increase the imaging depth by removing the lipid which is scattering factor, whereas 3DISCO, SeeDB, and ClearT increase the imaging depth through the index matching. Because scattering is proportional to refractive index gap, index matching reduces the scattering. These clearing techniques open up the possibility of the deep brain imaging. With the help of this modern pioneering tissue clearing technique, fluorescence microscopy including confocal microscopy (CM), multi-photon microscopy (MPM), and single plane illumination microscopy (SPIM) now enables us to image brain much deeper than ever before. Although efforts to eliminate the problematic light scattering have been ongoing for past decades, previous research has rarely reported quantification of enhancement light penetration into the cleared brain. They have only focused on the capability of three-dimensional visualization; A few quantification studies end up in measurement of transmittance or depth profile. Limitation of these studies was not able to provide the analysis of tissue property change induced by tissue clearing and to compare the tissue clearing characteristics. That is, there have not been standardized techniques to measure the clearing efficiency of regional differences and to investigate the principle of various tissue clearing methods, despite its significant need for reliability and reproducibility. Here, we present optical coherence tomography (OCT) and magnetic resonance imaging (MRI) to quantitatively assess the tissue clearing technique. OCT can perform label-free, non-invasive optical imaging by using Michelson interferometer. Thanks to these strong characteristics, OCT is appropriate tool to validate increase of imaging depth through the analysis of A-line profile. Therefore, we quantitatively measured the effect of diverse clearing even each brain region by using OCT. On the other hands, MRI is also non-invasive imaging technique based on nuclear magnetic resonance (NMR). Because MRI signal is based on atomic characteristics, we can physically investigate the fundamental principle of tissue clearing by monitoring the tissue atomic properties change. Through this study, we can investigate the diverse tissue clearing characteristics and compare the existing clearing technique. Furthermore, we provide the standard to evaluate the various tissue clearing and it allows the choice of proper tissue clearing for experimental purpose. Therefore, this study is able to increase the reliability and reproducibility of experimental results.

Have you seen the wind?

Sunwoo, Ahjung Hankuk University of Foreign Studies Graduate Scho 1998 국내석사

(A) comparative study of freedom of the press in Korea, Taiwan, and the Philippines in the 1960s

Nam, Sunwoo [UMI] 2014 국내박사

(A) study on exploring people's affinity for solitude

Lee, Sunwoo UMI Dissertation Publishing 2013 국내박사

Security analysis on digital signature function implemented in electronic document software

Park, Sunwoo Sungkyunkwan University 2013 국내석사