GLUE-based uncertainty assessment of SURR model in Imjin River basin

Trinh, Ha Linh Sejong University 2016 국내석사

The uncertainty in hydrological model can be caused by various sources, such as the model input data, non-optimal model parameters and model structures. For regional studies, the model parameters and uncertainty of input data are acknowledged as the two important sources of uncertainty. Particularly the Imjin river basin has the unique geographical characteristics with river cross operation between North and South of Korea. The insufficient metro-hydrological information in the northern region may lead to significant errors on the flow simulations. In the calibration and verification processes applied on the SURR (Sejong University Rainfall - Runoff) for rainfall - runoff simulations, it was found that the SURR simulated flows in the northern region of Imjin basin (Gunnam station) had the least accuracy as compared to the other two stations located in the southern area (Jeonkok and Jeogseong station) for all events (2007, 2008, 2009, 2010). This was due to the less precise calibrated parameters and the insufficient information of weather data in this station. Therefore the objective of the dissertation is to quantify the uncertainty of flow simulation based on GLUE (Generalized Likelihood Uncertainty Estimation) method model for the model parameter and precipitation input data in Imjin basin. To examine the uncertainty on streamflow simulation, two indexes are used: (i) p-factor, the ratio of the number of observations fall inside the uncertainty interval, and (ii) r-factor, the width of uncertainty interval. The results showed that the uncertainties of the simulated flow in the northern station are always high for both parameter and input uncertainty estimations. This was caused by the variations of two parameters, ALPHABF and SURLAG in the Gunnam station were significant larger than those of the southern stations. Meanwhile, the interpolated rainfalls in this area were also less accuracy due to the extremely far distance to the observed rain gauges in southern area. This reason explains why the input uncertainty in the northern area of Imjin basin always higher than the southern area. In addition, the dissertation also stated that the parameter uncertainty in streamflow was also influenced by the different periods of the hydrograph. The peak flows had higher uncertainty than the flows at the beginning or the end of each event.

One-dimensional flux power spectrum and cosmology with the SDSS-IV eBOSS lyman-α forest

이영배 Sejong University 2019 국내석사

As a unique tracer of the high-redshift cosmic web complementary to lower-z probes, the Lyman-α (Lyα) forest represents a powerful cosmological tool especially sensitive to the dark sector, via significant attenuation effects on the matter and flux power spectra at small scales. Among all Lyα forest observables, the small-scale one-dimensional flux power spectrum (P 1D F ) plays a key role, being highly sensitive to a wide range of cosmological and astrophysical parameters, neutrino masses, and the nature of dark matter. Hence, there is considerable interest in obtaining estimates of P 1D F from highquality data. To this end, we present here novel detailed measurements of P 1D F spanning the redshift interval 2.2 < z < 4.4, from the Data Release 14 (DR14) of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), part of the Sloan Digital Sky Survey IV (SDSS-IV). In particular, we carefully quantify and subtract all the contaminations induced by metals and pipeline noise, along with additional systematics caused for instance by the presence of Damped Lyman-α Systems (DLAs). We then confront our P 1D F measurements with state-of-the-art hydrodynamical simulations from the ‘Sejong Suite’, and find excellent agreement. Our new estimates of the small-scale eBOSS DR14 line-of-sight flux power spectra open the door for obtaining competitive cosmological constraints on neutrino masses, warm dark matter, and dark radiation – exploiting high-redshift quasars. Our study also provides a more solid understanding of the sensitivity and constraining power of the Lyα forest to the dark sector, and on the high-z small-scale clustering.

Improving the short-range flood forecasting capability of a coupled meteorological and hydrological model

Nguyen, Hoang Minh Sejong University 2019 국내박사

Flooding is one of the most serious and frequently occurring natural disasters in many regions around the world. In particular, given climate change, the impacts of flooding increase over time. To mitigate the damages caused by floods, flood forecasting is required to support water resource managers. Unfortunately, the accuracy of such forecasts remains limited because of the uncertainties that arise from various sources. These uncertainties may result in ineffective mitigation of flood damages. The coupling of meteorological and hydrological models is one of the most common methods for predicting streamflow. In this method, the capability of the streamflow predictions depends strongly on the performance of numerical weather prediction (NWP) model. However, the outputs of NWP models, especially quantitative precipitation forecasts (QPFs), are usually only somewhat skillful. This leads to the requirements for increasing the skills of QPFs. The improvements in QPFs are not required only in term of qualitative and quantitative skills but they also must involve the increase in probabilistic skill that is very valuable for the warnings of heavy rainfall and flooding. Because deterministic forecast may not really useful in the probabilistic forecast, ensemble predictions, which could address this problem, are thus becoming increasingly common and widely applied. Ensemble predictions allow analyzing qualitative and quantitative skills by using ensemble mean and probabilistic skill by considering all of their members. Ensemble QPFs can be derived from multiple runs of NWP model and statistically post-processing deterministic forecasts. By dint of the quick operation in ensemble streamflow prediction and non-requirement of high computational resources, the latter has been a subject of interest in several previous studies. However, the methods proposed in previous studies often require a large amount of historical forecast data for estimating parameter set. Hence, they are not suitable for applying to deterministic NWP models that have been launched operationally for a short time. Besides, these methods were only applied to medium-range (3-15 days) forecasts with accumulated rainfall in several hours or seasonal forecasts with daily rainfall totals. The applications for short-range (12-72 hours) forecasts with hourly rainfall have not been considered because hourly rainfall has a more greatly skewed distribution and higher intermittency of precipitation. Even though a method that could address these issues was proposed in a study, its effectiveness was not high due to the strong dependence of generated ensemble predictions on deterministic forecasts. Therefore, this study was conducted to propose a method, which could address the limitations of previous studies, for improving the capability of short-range rainfall and flood forecasts using a coupled meteorological and hydrological model. Three individual approaches including ensemble generation, blending, hydrological correction and real-time correction (Kalman filter technique) are developed and applied. To generate the ensemble precipitation prediction from single-valued rainfall forecast, the qualitative and quantitative skills are firstly evaluated at previous time step window and are then used to define the perturbation weights of QPF issued at current time by looking up a table. Ensemble QPF, which is generated as a kind of Monte-Carlo simulation, is highly dependent on the performance of deterministic NWP model because its members oscillate around the deterministic rainfall forecast. A blending technique is applied to mitigate this dependence by taking the advantages of radar-based rainfall prediction which is the best forecast for very short-range (6 hours ahead). This technique only reduces the rainfall intensity errors without considering the spatial rainfall errors (mis-location and extent) that have considerable contributions in the accuracy of rainfall and flood forecasts. Thus, a rainfall correction method that may involve the spatial rainfall errors is proposed. Target basin is located into different zones to account for the errors inside the basin and contiguous areas. Forecast errors in each zone basin are evaluated at previous time step window and then displaced to the target basin by performing a hydrological correction. Next, the forecast errors are continuously predicted and updated in real-time by using a Kalman filter technique and are then used to verify the rainfall forecast of each ensemble member; this process is called Kalman correction. Finally, each ensemble member is forced in turn as input for a rainfall - runoff model to obtain ensemble streamflow prediction. To validate the performance of the proposed method, it was applied to improve the capability of short-range rainfall and flood forecasts for the two flood events that occurred in 2013 and 2016 on the Yeongwol watershed using a coupled Local Data Assimilation and Prediction system (LDAPS) and Sejong University Rainfall - Runoff (SURR) model. Ensemble precipitation predictions were generated from the rainfall forecasts of the deterministic LDAPS model and were then blended with the McGill algorithm for precipitation nowcasting by Lagrangian extrapolation (MAPLE) rainfall predictions to produce hybrid rainfall forecasts. These hybrids continued to be verified by applying the rainfall correction method that involves the forecast errors caused by mis-location and extent. Eventually, each ensemble member of the verified hybrids was used to driver the SURR model to obtain the ensemble streamflow predictions on the watershed. The performance of the method was evaluated in term of qualitative (Proportion Correct (PC), Critical Success Index (CSI), Bias ratio, and False Alarm Ratio(FAR)), quantitative (Root Mean Square Error (RMSE), Mean Error (ME), Mean Absolute Error (MAE), Correlation Coefficient (CC), Model Efficient (NSE), and Absolute Relative in Volume (AREV)), and probabilistic (Brier score) skills. The results showed that the capability of rainfall and flood forecasts using the coupled model was improved sustainably step by step and exhibited the best skills after applying the final step that is Kalman correction. For rainfall forecast, the values of PC, CSI, and Bias averaged over total lead time were improved dramatically by 59%, 60%, and 106%, respectively, for flood event in 2013; 39%, 40%, and 257%, respectively, for flood event in 2016, whereas the improvements in RMSE, ME, MAE, and CC were 32%, 74%, 16%, and 32%, respectively, for flood event in 2013; 15%, 97%, 8%, and 33%, respectively, for flood event in 2016. The probabilistic skill increased dramatically with values of Brier score decreasing by 48% and 37% for flood events in 2013 and 2016, respectively. For flood forecasting, the improvements in RMSE, NSE, AREV, and ME were 30%, 63%, 24%, and 103%, respectively, in 2013; 42%, 42%, 53%, and 134%, respectively, in 2016. The success of this case study proved the viability of the methodology proposed in this study. A notable point is the application of the linear Kalman filter technique for correcting the rainfall forecast of each ensemble member, which may not produce the highest effectiveness of the rainfall correction method. Further study would be conducted to investigate the performance of non-linear ensemble Kalman filter technique for improving the effectiveness of the method.

Development and evaluation of a single-use multi cell culture system

박범석 Sejong University 2018 국내석사

A variety of biopharmaceuticals such as antibodies, proteins, and gene/cell therapeutics have been developed in recent decades and demands for them have increased dramatically every year. To meet such demands, it is essential to cultivate cells that produce biopharmaceuticals in large-scale bioreactors and it is very important to optimize culture conditions for massive production of biopharmaceuticals. Scaling down technology, using multi- and small size (less than 100 mL) bioreactors, has been an effective tool for applying DoE (Design of Experiment) and QbD (Quality by Design) for process optimization of large scale cell cultures. In this study, a newly developed single-use multi-bioreactor system that can control the pH, DO, and culture temperature of each bioreactor which is expandable to 24 bioreactors in a multi bioreactor culture system is introduced. Also, the evaluation of biological and physical performances of this single-use multi cell culture system are explored. Through these evaluations and development researches, we suggested direction of development of a single-use multi cell culture system. Ultimately, this research implies that this cell culture system newly being developed will be a practical and efficient device in the bioprocess industry. 과거부터 현재까지 바이오 의약품의 수요는 지속적으로 증가하고 있으며, 이를 충족하기 위해서는 세포의 대량 배양 혹은 이를 통한 바이오 의약품의 대량생산이 필요하게 된다. 이를 위해서는 바이오리액터 활용한 바이오공정 개발을 통해 바이오 의약품의 생산성을 증대 시키기 위한 조건을 확립 해야 한다. 그렇지만 초기 배양 공정 개발에서 사용되는 L 급의 벤치 스케일 바이오리액터는 수 많은 배양 조건을 최적화 하기에는 경제적인 면과 시간적인 면에서 불리 할 수 밖에 없다. 이러한 상황에서 최근에는 scaledown 모델인 mL 급의 바이오리액터 시스템의 활용이 주목을 받고 있으며, 이러한 시스템은 기존 바이오리액터의 세포의 배양 환경을 유지하는 기능을 그대로 갖고 있기 때문에 최적의 공정 조건 확립에 용이하며 경제적인면과 시간적인 면에서 큰 이점을 갖고 있다고 할 수 있다. 본 연구에서는 이러한 scale-down 모델인 일회용 멀티 세포 배양 시스템의 개발을 위한 물리적 및 생물학적 평가와 개발 연구를 수행하였다. 첫번째로, 일회용 멀티 세포 배양 시스템의 배양 용기인 Mini-bioreactor의 물리적 특성과 세포배양능을 평가하였다. KLa 와 Mixing time을 상업 용 배양 용기와의 비교를 통해서 세포 배양을 위한 RPM 조건을 선정할 수 있었고, 선정된 배양 조건에서 회분 식 배양과 유가 식 배양을 통해 세포 배양능을 상업 용 배양 용기 및 배양기와 비교 분석하였다. 결과적으로, 상업용 제품과 동등 내지 우수한 세포 배양 능 및 항체 생산성을 확인할 수 있었다. 두번째로, 세포 배양액의 pH 와 DO 값을 측정하기 위한 패치 형 광학센서의 특성 및 안정성을 SDR 시스템을 이용하여 평가하였다. 이를 위해 다양한 상업 용 및 In-house 배지를 이용하였으며, 결과적으로, 광학 리더기 의 excitation light는 영향이 없었으나, 시간이 지남에 따라 광학 센서의 안정성이 다소 떨어지는 것을 확인 할 수 있었고, 특정 색소의 경우에는 이 러한 광학 시스템에 부정적인 영향을 끼친다는 것을 확인 할 수 있었다. 세번째로, 세포 배양액의 pH 값의 유지를 위한 pH 조절 시스템을 개발하기 위해, pH 조절 탱크 내부의 다양한 구성 방식과 분출 원리 및 최적 조건을 확립하고 재평가를 함으로써, 염기 용액을 배양 용기 내부로 소량 분출할 수 있는 pH 조절 시스템을 고안하였다. 결과적으로, 이와 같은 평가 및 개발 연구를 통해, 원활한 세포 배양 기능을 갖춘 일회용 멀티 세포 배양 시스템의 개발을 위한 방향성을 제시할 수 있었으며, 궁극적으로 본 연구는 이러한 세포 배양 시스템이 바이오 제약 산업에서 실용적인 배양 장치가 될 수 있음을 시사한다.

Topology, size and shape optimization of structures using isogeometric analysis

Lieu, Xuan Qui Sejong University 2018 국내박사

This dissertation is concerned with topology, size and shape optimization of structures based on isogeometric analysis (IGA). For topology one, a novel isogeometric multi-resolution scheme within the framework of the Solid Isotropic Material with Penalization approach (SIMP) approach is proposed to perform single material topology optimization. This isogeometric multi-resolution topology optimization (MTOP) produces higher-resolution designs with a lower computational cost over the conventional topology optimization (without MTOP) by using coarser analysis meshes. Furthermore, optimized designs include highly discrete solutions in terms of solid and void materials by applying a refined sensitivity filter without using any black and white projection filters. Various benchmark test problems including plane stress, compliant mechanism inverter, and 2-dimensional heat conduction are examined to demonstrate the effectiveness and robustness of the present method. Subsequently, the present method is first integrated into the alternating active-phase algorithm to implement multi-material topology optimization for 2D plane stress problems. Additionally, this thesis also suggests a novel effective methodology for modeling and optimizing the material distribution (size) of ceramic-metal functionally graded (FG) plates subjected to the thermomechanical load. In this approach, ceramic volume fraction design variables at control points whose coordinates are located along the plate thickness by Greville abscissae are used to describe the material distribution using the B-spline basis functions. A non-uniform rational B-splines (NURBS)-based isogeometric finite element model associated with the third-order shear deformation theory (TSDT) is utilized for the static analysis of the FG plates. A recently develop ed non-gradient-based algorithm which is the so-called adaptive hybrid evolutionary firefly algorithm (AHEFA) is employed to solve compliance minimization problems under volume constraints. This algorithm speeds up the convergence of optimization process and enhances the accuracy of optimal solution. For size and shape optimization, an effective and robust methodology for modeling and simultaneously optimizing the layer thicknesses (shape) and the ceramic volume fraction distribution (size) of the FG sandwich plates under free vibration is developed. The multi-patch B-spline basis functions separately defined in each of the layer thicknesses are used to represent the ceramic volume fraction distribution via a set of control points whose coordinates are given in each layer thickness according to Greville abscissae. TSDT-based IGA is utilized for the plate free vibration analysis, and the AHEFA is utilized as an optimizer. Two types of optimization problems of the FG sandwich plates, including (i) the first natural frequency maximization with volume constraints, and (ii) mass minimization with frequency constraints, are presented to illustrate the effectiveness and reliability of the proposed method.

Research and application technique on scattering-based remote sensing in a variety of spectral bands

권영주 Sejong University 2019 국내박사

원격 탐사 기법은 수문학, 지질학, 생태학 등 많은 지구과학 연구 분야에 사용되어 왔다. 특히 위성을 이용한 원격 탐사 기법은 동일한 정밀도로 넓은 영역을 관측할 수 있다는 장점이 있다. 이 학위 논문에서는 다양한 원격탐사 기법 중 산란 특성을 원격탐사 활용 기술을 제시하고자 한다. 산란 기반 원격 탐사 기술을 사용한 활용 기술로 육상 강수 알고리즘, 토양 수분 산출 알고리즘 및 black ice 탐지알고리즘을 개발했다. 강우량은 한반도의 생명과 재산에 영향을 미치는 주요한 자연 재해이다. 본 학위논문에서는 GCOM (Global Change Observation Mission)-W1 위성의 Advanced microwave Scanning Radiometer 2 (AMSR-2) 센서를 이용하여 36.5와 89.0 GHz 채널의 편광 보정 온도 (PCT)와 산란 지수 (SI) 자료를 활용하여 한반도 남부에 최적화된 위성 기반 육상 강수 산출 알고리즘을 개발했다. 강수량 산출을 위한 AMSR-2 계수는 2012-2015년 7월 1일부터 8월 30일까지 동안의 관측자료를 사용했다. AMSR-2 관측자료와 지상 AWS 강우 측정 사이에는 약 25 분의 시간 지연이 있음을 발견했다. 강우 산출 알고리즘은 2016년 7월 1일부터 8월 30일까지 여름철 AWS 강수량 관측 자료로 검증했다. 개발된 알고리즘은 ASMR-2 (L2) 강수 산출물 자료와 비교했을 때, 36.5 GHz PCT 기반 산출 기법이 가장 좋은 결과를 보였다(bias = 2.09 mm h-1, RMSE = 7.29 mm h-1). MODIS 가시/적외선 채널 반사도에서 얻은 NDVI와 LST를 기반으로 TVDI를 계산하고, 이로부터 토양수분을 추정하는 알고리즘을 개발했다. 고도 효과를 고려한 LST를 사용하면 보다 현실적인 TVDI를 계산할 수 있다는 사실을 발견했다. 계산된 TVDI는 GLDAPS의 토양 수분 자료와 비교하여 얻은 변환 방정식을 사용하여 지표 토양 수분을 계산했다. MODIS 기반 토양 수분 산출 알고리즘은 일본의 정지 위성인 Himawari-8/AHI에 적용했다. 정지 궤도 위성은 수동 마이크로파 위성 데이터보다 높은 공간 분해능 자료를 생산한다는 장점이 있다. 가시/적외 채널의 한계인 구름 및 대기 조건의 영향은 높은 시간 해상도 자료를 활용하여 최소화할 수 있다. Himawari-8/AHI 관측에 적용된 토양 수분 알고리즘은 정지 인공위성을 기반 토양 수분 산출의 가능성 확인할 수 있었다. 마지막으로 본 학위논문에서는 GPS 반사 신호를 이용한 효율적인 블랙아이스 검출 시스템과 기법을 제안했다. GPS 반사파 신호를 측정하기 위한 GPS 탐지 시스템을 구축했다. 이 시스템은 GPS L1 대역의 RHCP 및 LHCP의 편광 신호를 측정하기 위해 2개의 GPS 안테나와 3개의 수신기로 구성된 장비로 하도록 설계되었다. 다른 장소에서 수행된 2번의 GPS 반사파 측정 현장 관측 실험을 수행했다. GPS 수신기 모듈을 이용한 실험을 통해, 아스팔트와 얼음 표면 사이의 반사파 강도의 차이가 확인되었다. 또한 도로 표면의 블랙아이스 탐지를 위한 방법론적으로 NPRI라는 지수를 제시했다. 현장 실험 관측 자료는 45°와 55° 사이의 위성 고도각에 대해 NPRI 값이 -0.1보다 큰 아스팔트 도로에서 블랙아이스를 검출할 수 있었다. 날씨 정보를 함께 수집하면 블랙아이스 추정에 활용한다면 정확도가 향상될 것으로 기대한다. Remote sensing has used in numerous Earth Science research field such as hydrology, ecology, meteorology, oceanography, glaciology, geology. Remote sensing using satellites provides continuous measurement with a much wider surface area on a regular basis. In this paper, we try to present application technology utilizing the scattering characteristics among the various remote sensing techniques. Using the scattering-based remote sensing technique, we developed retrieval algorithms for precipitation over land, soil moisture and black ice detection. Heavy summer rainfall is a primary natural disaster affecting lives and properties in the Korean Peninsula. The rain fall from the convective system can lead to dangerous social and economic losses. This study presents a satellite-based rainfall rate retrieval algorithm for the South Korea combining polarization-corrected temperature (PCT) and scattering index (SI) data from the 36.5 and 89.0 GHz channels of the Advanced microwave Scanning Radiometer 2 (AMSR-2) onboard the Global Change Observation Mission (GCOM)-W1 satellite. The coefficients for the algorithm were obtained from spatial and temporal collocation data from the AMSR-2 and ground-based automatic weather station rain gauges from 1 July - 30 August during the years, 2012-2015. There were time delays of about 25 minutes between the AMSR-2 observations and the ground rain gauge measurements. A new linearly-combined rainfall retrieval algorithm focused on heavy rain for the PCT and SI was validated using ground-based rainfall observations for the South Korea from 1 July - 30 August, 2016. The validation presented PCT and SI methods showed slightly improved results for rainfall > 5 mm h−1 compared to the current ASMR-2 level 2 data. The best bias and root mean square error (RMSE) for the PCT method at AMSR-2 36.5 GHz were 2.09 mm h−1 and 7.29 mm h−1, respectively, while the current official AMSR-2 rainfall rates show a larger bias and RMSE (4.80 and 9.35 mm h−1, respectively). This study provides a scattering-based over-land rainfall retrieval algorithm for South Korea affected by stationary front rain and typhoons with the advantages of the previous PCT and SI methods to be applied to a variety of spaceborne passive microwave radiometers. We developed the soil moisture retrieval algorithm using TVDI calculated using the NDVI and LST obtained from the surface reflectivity of the MODIS. A more realistic TVDI was calculated using the surface temperature considering the elevation effect. The TVDI can be calculated the surface soil moisture using the conversion equation obtained by comparing with the soil moisture data of GLDAPS. MODIS-based soil moisture retrieval algorithm was applied to geostationary satellite Himawari-8. Geostationary satellites have the advantage of higher spatial resolution data than passive microwave satellite data. Using the high temporal resolution characteristics, geostationary satellites can minimize the influence of cloud and atmospheric conditions which is general limitation of satellite data at visible/infrared channel. The soil moisture algorithm applied to the Himawari-8/AHI observations confirmed the promising soil moisture estimation based on geostationary satellites. We propose an efficient black-ice detection system and technique using GPS reflected signals. The GPS black ice detection system consists of GPS antenna and receiver to measure the power of GPS L1 band signal strengths. The GPS receiver system was designed to measure the signal power of RHCP and LHCP from direct and reflected signals using two GPS antennas. The field experiments of GPS reflection measurements at two different sites were performed. Two observations were carried out using the GPS receiver module and the difference of reflected wave intensity between asphalt and ice surface was confirmed. Methodologically, we present a NPRI to determine the presence of black ice on road surfaces. Consequently, the field experiments in two different sites results in the successful black ice detection on asphalt roads with NPRI value greater than -0.1 for the elevation angle between 45° and 55°. We expect that estimation accuracy of the technique will be improve if we collect weather information together.

Size dependent characteristics and ginsenosides bioconversion efficacy of red ginseng powder

김영은 Sejong University 2018 국내박사

인삼 (Panax ginseng C.A. Meyer)은 우리나라 및 아시아에서 가장 일반적으로 사용되는 전통 한약재이다. 시중에서 판매되는 인삼은 수삼, 백삼 그리고 홍삼으로 분류된다. 홍삼은 수삼을 98 ~ 100 ℃에서 2 ~ 4 시간 동안 쪄서 건조시켜 제조한다. 홍삼은 고유한 진세노사이드 프로파일을 가지고 있으며, 진세노사이드는 온도, pH, 효소 및 미생물의 반응에 의해 탈글리콜화 되고, 이렇게 생성되어지는 진세노사이드의 약용 가치가 있다는 연구결과들을 다수 확인할 수 있다. 홍삼이 함유하고 있는 진세노사이드는 인체에서 대부분 흡수되지 않아, 다른 형태의 진세노사이드로 전환되어야 하는 진세노사이드 Rb1, Rb2, Rc 및 Rd를 함유한다. 체내 흡수가 용이하고, 생체이용율이 높은 진세노사이드 Rg3, Rg5, Rk1, Rh1, F2, compound K 및 PPD와 같은 진세노사이드는 Rb1, Rb2, Rc 및 Rd와 같은 기질 사포닌으로부터 위산, 효소 및 미생물에 의해 전환되어 생성된다. 최근 초미세 분쇄 기술에 대한 관심 및 연구가 많아지고 있다. 초미세분쇄 기술은 비표면적을 최대화하여 용해도 및 분산성을 향상시키는 것이특징이며, 재료의 물리적 손상과 화학적 변형을 최소화하면서 손상을 최소화 할 수 있다는 장점을 가졌다. 본 연구에서는 홍삼분말의 입자크기가 진세노사이드의 생체 및 효소전환에 미치는 영향을 조사하기 위해 먼저 홍삼분말의 사이즈를 다르게 제조하였다. 일반적인 분쇄공정을 거쳐 제조되어진 홍삼분말 (CRP, Coarse red ginseng powder), 그리고, 초미세분말 제조장비를 이용하여 1차 제조되어진 미세홍삼 분말 (FRP, Fine red ginseng powder) 이후 3단계의 초미세 공정을 거쳐 제조되어진 3가지 사이즈 (32 μm, 23 μm, 20 μm)의 초미세 홍삼분말 (URP, red ginseng powder)과 같은 5가지의 사이즈가 다른 홍삼 분말을 준비했다. 준비된 홍삼분말CRP, FRP 및 URPs의 평균 입자 크기는 각각 509.799 μm, 93.848 μm, 32.814 μm, 23.164 μm, and 20.814 μm 이었고, Uniformity 값은 0.5 ~ 0.8 범위 이내였다. 진세노사이드의 전환 등에 가장 크게 영향을 줄 것이라고 판단되는 비표면적 값은 각각 0.031 ± 0.001, 0.202 ± 0.001, 0.412 ± 0.003, 0.471 ± 0.002, and 0.513 ± 0.002 m2/g이었다. 이 결과를 토대로 입자가 작아질수록 비표면적이 커짐을 확인 할 수 있었다. 비표면적이 넓어질수록 체내흡수 및 기능성이 증가한다는 가설 확인을 위해 DPPH 라디컬 소거능을 확인해본 결과 사이즈가 비표면적이 넓어질수록 항산화 효능이 커짐을 확인할 수 있었다. 인삼 및 홍삼을 이용하여 제조되어진 초미세 분말은 대부분 추출물의 수율 향상 및 용해도 증진에 대한 연구에 이용되며, 체내흡수율 및 효능에 대한 연구는 추출물을 이용한 것이 대부분이다. 하여 본 연구에서는 제조되어진 5가지 홍삼분말을 이용하여, 체내흡수가 용이한 형태의 진세노사이드로의 전환율을 검증하는 연구를 수행하였다. 먼저 in vitro 위장관 조건에서의 진세노사이드 전환율 확인을 위해 사이즈가 다른 홍삼분말을 물에 넣은 후 37 ℃의 항온 배양기에서 펩신 용액과 리파아제, 담즙 추출물 및 팬 크레아틴 혼합물을 첨가 하였다. 반응시간 동안 Rg3, Rg5, Rk1 및 PPD와 같이 생성되는 진세노사이드는 시간에 따라 증가하였고, 기질 화합물 (ginsenoside Rg1, Re, Rb1, Rb2, Rc 및 Rd)은 감소하였다. 홍삼 분말의 사이즈가 작아질수록 증가 된 비표면적은 위장관 상태에서 빠르게 기질 화합물을 전환시켜 체내흡수가 용이한 형태의 진세노사이드를 생성하였다. URP-23과 URP-20 이 FRP 보다 많은 기질 ginsenosides를 전환시킨 이유는 2 단계 분쇄에 의해 얻어진 URPs가 작은 입자의 형성과 그에 따른 비표면적의 증가로 인해 FRP보다 빠른 방출력을 가졌기 때문이라고 생각된다. 그리고 종양의 형성을 차단하고 암세포의 침입을 억제함으로써 암의 발생 및 전이를 예방한다고 보고되어졌고, 진세노사이드 Rb1, Rb2, Rc 및 Rd의 주요 대사 산물인 진세노사이드 F2와CK의 생성에 관해 연구하였다. CK는 홍삼 뿌리에서는 발견되지 않지만, 대장에서 효소의 작용에 의해 진세노사이드 Rb1, Rb2, Rc 및 Rd가 CK로 전환되어 우수한 생체 이용률을 갖는다. 진세노사이드F2와 CK의 효소 전환은 pH 4.3과 55 ± 1 ℃에서 cytolase PCL 5를 사용하여 수행되었다. 홍삼 분말의 입자 크기가 작을수록 진세노사이드 F2와 CK의 전환율이 증가함을 확인할 수 있었다. 이처럼, 홍삼 분말의 입자 크기가 작아짐에 따라 체내대사 중에 항산화 효과가 증가함을 확인 할 수 있었으며, 생체 및 효소 처리를 통한 대사에서 체내흡수가 용이한 형태의 진세노사이드의 양이 증가 하는 등의 결과는 홍삼 분말의 입자 크기를 줄이는 것이 인체에서의 진세노사이드의 생체 이용률 향상에 크게 기여 함을 시사한다. Red ginseng contains ginsenoside Rg1, Re, Rb1, Rb2, Rc, and Rd which are hardly absorbed in the human body but are converted to other forms of ginsenosides. Bioavailable ginsenosides such as Rg2, Rg3, Rg5, Rk1, F2, compound K, PPT and PPD are produced through bioconversion from substrate ginsenosides such as Rg1, Re, Rb1, Rb2, Rc, and Rd by gastric juices, enzymes, and microorganisms. In this study, the effects of particle sizes of red ginseng powder on its ginsenoside bioconversion under simulated gastrointestinal conditions or enzymatic treatment were investigated in order to improve the bioavailability of red ginseng powders. Specially, the ultrafine milling technique that has the advantage of maintaining the physicochemical properties of plant materials and increasing the extraction yield and solubility, was applied to prepare red ginseng powders with five different particle sizes such as coarse red ginseng powder (CRP), fine red ginseng powder (FRP), and ultrafine red ginseng powders of three different sizes (URP-32, 23, 20). The average particle sizes of CRP, FRP, URP-32, URP-23 and URP-20 were determined to be 509.799, 93.848, 32.814, 23.164, and 20.814 μm, respectively. The uniformity value ranges of CRP, FRP, URP-32, URP-23 and URP-20 were in a range of 0.555-0.815. For bioconversion tests under simulated gastrointestinal conditions, red ginseng powders were dissolved in water, pepsin solution and a mixture of lipase, bile extract, and pancreatin was added to the solutions, followed by the incubation at 37°C. During the bioconversion tests, the levels of the substrate compounds (ginsenoside Rg1, Re, Rb1, Rb2, Rc, and Rd) decreased while those of the product compounds such as Rg3, Rg5, Rk1, and PPD increased over time. The total conversion rates of substrate ginsenosides under the simulated gastrointestinal conditions were 31.19%, 40.19%, and 45.79% for FRP, URP-23, and URP-20, respectively. The DPPH radical scavenging activities of CRP, FRP, URP-32, URP-23 and URP-20 were 0.32%, 0.90%, 1.43%, 1.72%, and 2.25%, respectively. The antioxidant effect of FRP, URP-23, and URP-20 increased as the particle sizes of the red ginseng powders decreased. Compound K, a major metabolite of ginsenosides Rb1, Rb2, Rc, and Rd, has been recognized to prevent the development and the metastasis of cancer by blocking the formation of tumors and suppressing the invasion of cancerous cells. Specific surface area determination supported this observation. When the specific surface areas of red ginseng powders were larger, substrate ginsenosides were more rapidly bioconverted under the gastric condition. The bioconversion of substrate ginsenosides into ginsenoside F2 and compound K was implemented using cytolase PCL 5 at pH 4.3 and 55 ± 1°C. The contents of ginsenoside F2 and compound K after enzymatic treatment were 11.22 mg/g, 10.25 mg/g, and 5.06 mg/g in the case of URP-23, URP-20, and FRP, respectively. The rates of enzymatic conversion into ginsenoside F2 and compound K increased as the particle sizes of the red ginseng powders decreased. Based on the results, two types of bioconversion, one under simulated gastrointestinal conditions and the other through enzymatic treatment of product ginsenosides increased as the particle sizes of the red ginseng powders decreased. These findings suggest that the reduced particle size of red ginseng powder can contribute significantly to the enhancement of the bioavailability of ginsenosides in the human body.

Women in Thai and Korean dramas : the portrayals and viewers' perceptions of female characters

Pushsapavardhana, Nuntipa Sejong University 2018 국내박사

대중매체에 묘사된 여성상은 시청자, 드라마 프로듀서 및 여타 사회구성원들 사이에서 상당한 논란을 일으켜 왔다. 남녀평등주의의 여파에도 불구하고 태국의 대중매체 및 여타 국가의 대중매체, 특히 드라마 속의 여성에 대한 비교연구만으로는 충분치 않다. 2006년에서 2015년 사이에 태국과 한국 드라마에 비쳐진 여성상을 분석한 두 차례의 연구를 통해 문학에 기여할 목적으로 시도한 본 연구에서는 태국과 한국 드라마 간의 유사점과 차이점을 검토하였고, 태국 여성시청자들의 여성 등장인물에 대한 인식을 조사하였다. 정량적 분석을 위해 태국과 한국 드라마 848회에서 총 200명의 여성 등장인물을 선정하여, 이 등장인물들이 비교적 유사한 인구통계적 특징을 가졌음을 확인했다. 하지만 여성들의 신체적 외모, 성격적 특성, 성적 역할 및 사회적 상호관계에서 유의한 차이가 있음을 발견했다. 추세분석 결과, 한국 드라마에서는 신체적 외모, 성적 역할 및 사회적 상호관계에 대한 현대적 정형의 묘사에 있어 상당한 변화를 보였지만, 태국 드라마에서는 동일한 묘사를 보이는 통계적 등식은 없었다. 또한 여성의 성격적 특성에 대한 묘사변화의 통계적인 증거는 없었다. 22세에서 58세 사이의 태국 여성시청자 30명을 대상으로 한 5개 표적집단 토의에 대한 정성적인 분석 결과, 시청자의 대다수가 학사학위를 취득했고 기업부문에 종사하고 있는 것으로 나타났다. 드라마 속의 여성 등장인물에 대한 이들의 인식은 네 가지 범주로 나뉘었다. 우선, 등장인물에 대한 태도 및 묘사의 영향에 대한 인식을 포함한 시청자들의 반응에 있어 문화적 차이의 인정, 개인적 경험 및 여성에 대한 묘사 등의 세 가지 요소가 중요한 것으로 확인되었다. 다음으로, 시청자들은 자신들의 인식형성을 위해 정보를 비교, 판단 및 탐구하는 세 가지 전략을 채택하였다. 그러한 전략은 사회적 가치, 자아가치, 개인적 경험, 드라마 등장인물의 유형, 드라마 시청자 층, 등장인물의 묘사 및 참여자의 연령 등과 같은 내, 외적 조건에 영향을 받았다. 마지막으로, 세 가지 유형의 인식이 확인되었다. 태국과 한국 드라마에 반영된 현실이 핵심적인 인식이었지만, 여성의 진화와 여성 묘사의 긍정적이고 부정적인 영향에 대한 인식 또한 중요하였다. The portrayal of women in the media has generated significant debate among the viewers, the drama producers, and other members of the society. Even in the wake of feminism, studies regarding the comparison of women in Thai media and other thee media of countries, especially dramas, are insufficient. The current study attempted to contribute to the literature by conducting two studies that analyzed the portrayals of women in Thai and Korean dramas between 2006 and 2015, examined the similarities and the differences between Thai and Korean dramas, and investigated the perceptions female characters among Thai female viewers. A total of 200 female characters from 848 episodes of Thai and Korean dramas were selected for the quantitative study and it was found that these characters had relatively similar demographic characteristics. However, the significant differences in the portrayals of women’s physical appearances, personality traits, gender roles, and social interaction were found. The results from trend analysis revealed a significant shift, in Korean dramas, in the portrayals of modern stereotypes of women’s physical appearances, gender roles, and social interactions, but there was no statistical equation to show the same portrayals in Thai dramas. Furthermore, there was no statistical evidence of a shift in the depictions of women’s personality traits. The results from a qualitative examination of five focus group discussions among 30 Thai female viewers aged 22 to 58 years revealed that the majority of them had attained a bachelor’s degree and worked in the business sector. Their perceptions of the female characters in the dramas fell into four categories. First, three factors, the acknowledgment of cultural differences, individual experiences, and the portrayals of women, were found significant in the viewers’ responses including attitudes towards the characters and the recognition of the effects of the portrayals. Then, three strategies for comparing, determining, and seeking information were employed by the viewers to form their perceptions. The strategies were influenced by the internal and external conditions such as social values, self-value, personal experiences, types of drama characters, drama viewership, the portrayals of the characters, and participant’s age. Finally, three types of the perceptions were found. The reality reflected in Thai and Korean dramas was the core perception, but the evolution of women and the awareness of positive and negative effects of the portrayals of women were also important.

Redox behavior of some selected metals in room temperature ionic liquids

Dilasari, Bonita Sejong University 2016 국내박사

Room temperature ionic liquid (RTIL) is a salt, consisting of large asymmetric cation and complex anion, which is stable in liquid phase below 100°C. Properties of RTILs are solely dependent on their constituent cation and anion. In terms of electrochemistry, the most significant properties of RTILs that should be considered are viscosity, conductivity, and electrochemical stability window. Electrochemical stability window, which refers to a potential range where cation and anion are neither reduced nor oxidized, of RTILs is typically wider than aqueous electrolytes. This feature enables electrodeposition of metals with large negative reduction potential such as aluminum, zinc, magnesium, and lithium, which are otherwise unable to be recovered in aqueous solvents. In battery application, replacing conventional organic solvents with nonvolatile and nonflammable RTILs would help to improve battery safety. This dissertation focuses on the electrochemical reactions of metal electrodes in RTILs, including electrodeposition and corrosion. Three different topics regarding the oxidation and reduction reactions of some selected metals in RTILs are discussed in this dissertation. The effect of RTIL structures on the electrodeposition/dissolution behavior of lithium is investigated in the first topic. The second topic is about the oxidation and reduction reversibility of zinc anode and the effect of water addition in RTIL-based zinc-air battery application. In the third topic, the corrosion susceptibility of some selected metals is evaluated in a protic RTIL containing available proton on cation, and compared with aprotic one with a similar structure. RTIL structure is confirmed to affect the electrodeposition/dissolution potential of lithium. The largest portion of lithium metal in deposits is obtained from a sample electrodeposited in RTIL with the widest electrochemical stability window, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMPyr] [NTf2]). In regard to the application of RTILs as an electrolyte for zinc-air battery, zinc electrode shows reversible oxidation-reduction reactions in [BMPyr] [NTf2]. However, the presence of water gives a significant effect on the redox reactions of zinc electrode. Protic RTIL (1-butylpyrrolidinium bis(trifluoromethylsulfonyl)imide) is confirmed to show a narrower electrochemical stability window compared to that of aprotic RTIL ([BMPyr] [NTf2]) of similar structure and is more reactive towards metals. Lower corrosion potentials and higher corrosion current densities are observed in the protic RTIL.

Identification and characterization of cell surface major vault protein (csMVP) in circulating tumor cells (CTCs) derived from liver cancer patients

이현민 Sejong University 2018 국내박사

Circulating tumor cells (CTCs) in peripheral blood play a major role in the initiation of hepatocellular carcinoma (HCC) metastasis and recurrence even after curative treatments. Major vault protein (MVP) is upregulated during malignant progression and drug resistance in various cancer cells. MVP has been known as a cytonuclear protein, but we found that MVP is expressed on the surface of HCC cells but not on the surface of normal hepatocytes. MVP knockdown decreases HCC cell growth and increases cell death, and treatment with anti-MVP antibodies (α-MVPs) recognizing cell surface MVP (csMVP) inhibits HCC cell proliferation, suggesting that csMVP contributes to HCC cell proliferation. The expression of csMVP is induced under stressful environments, and cell sorting revealed that csMVP (+) HCC cells have a higher clonogenic survival than csMVP (-) HCC cells. Treatment with α-MVP inhibits clonogenic survival and invasive and migratory potential of HCC cells, suggesting that csMVP contributes to cell survival, invasion and migration. csMVP-associated signaling also supports for the role of csMVP in the survival and metastasis of HCC cells. csMVP (+) CTCs are detected in HCC patients (approximately 88%) but not in healthy donors, and the number of csMVP (+) CTCs is further increased in cancer patients with liver metastases. csMVP is only detected in CTCs with mesenchymal phenotype or intermediate phenotype with neither epithelial nor mesenchymal markers. The results suggest that csMVP is a novel surface marker on CTCs with nonepithelial phenotype and promotes cancer progression through improving survival of CTCs in HCCs. 암 환자의 혈액에 존재하는 순환종양세포(Circulating tumor cells, CTCs)은 간암의 초기 전이나 재발에 중요한 역할을 한다. Major vault protein (MVP)는 다양한 암세포에서 악성으로 진행되고, 약물의 저항성 유발시 발현이 증가한다. MVP는 현재까지 세포질과 핵 단백질로 알려져 있었으나, 본 논문에서는 정상 간세포의 표면에는 발현하지 않으나, 다양한 간암세포 표면에서 발현하는 MVP를 동정 및 특성을 분석하였다. MVP를 결핍시킨 간암세포에서 세포 주기(Cell cycle)이 G2/M기에 정지되어 간암세포의 증식이 크게 감소되고, 세포 사멸도 크게 증가하였다. 세포 표면 MVP 항체를 처리해 본 결과 역시 간암세포의 증식이 억제되었다. 이러한 결과는 csMVP가 간암세포의 증식에 관여한다는 것을 알 수 있었다. csMVP(+) 간암세포와 csMVP(-) 간암세포를 분리하여 clonogenic survival을 분석한 결과 csMVP(+) 간암세포의 생존율이 csMVP(-) 간암세포의 생존율 보다 높게 나타났다. 동일 실험을 MVP항체를 처리한 것과 처리하지 않은 것으로 진행하였을 때 MVP항체를 처리한 군에서 생존율이 크게 떨어지는 것을 확인 하였으며, Migration과 Invasion 역시 크게 감소하는 것을 확인 할 수 있었다. 이러한 결과를 토대로 csMVP가 간암세포의 생존과 Migration 및 Invasion에 크게 관여하는 것을 알 수 있었다. 이러한 결과를 토대로, csMVP는 종양형성과 전이에 있어서 중요한 역할을 하고 있으며 FAK/mTOR 신호를 통해 간암의 성장과 전이를 조절 하는 것이라 생각된다. csMVP는 간암환자 혈액에 존재하는 CTC는 검출하지만, 정상인의 혈액세포에는 발현하지 않는다. 또한 타장기에서 간으로 전이된 암환자의 혈액에서 csMVP(+)-CTCs의 수가 크게 증가함을 알 수 있었다. 추가적으로, 이러한 csMVP(+)-CTCs가 중간엽성 (mesenchymal) 표현형을 보이는 것을 확인 할 수 있었다. 이러한 결과는 csMVP가 중요한 비상피성 표현형을 갖는 CTCs의 마커이며, 또한 csMVP(+)-CTCs는 암의 진행 및 생존에 있어서 중요한 역할을 할 것이라 제안 할 수 있겠다.