• Korean Journal of Remote Sensing
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• v.26 no.1
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• pp.59-64
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• 2010

The second satellite in ESA's Earth Explorer series, the Soil Moisture and Ocean Salinity (SMOS) mission was launched into orbit at November 1, 2009. The SMOS will play a key role in the monitoring of climate change on a global scale using the payload of L-band synthetic aperture radiometer. It is the first ever satellite designed both to map sea surface salinity and to monitor soil moisture on a global scale, and will provide the important data to study the water cycle among oceans, the atmosphere and land. To introduce the operation of the SMOS, this paper shows brief summary of appearance and current operation.

• Molecules and Cells
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• v.41 no.10
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• pp.889-899
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• 2018

Intrinsically disordered proteins (IDPs) are highly unorthodox proteins that do not form three-dimensional structures under physiological conditions. The discovery of IDPs has destroyed the classical structure-function paradigm in protein science, 3-D structure = function, because IDPs even without well-folded 3-D structures are still capable of performing important biological functions and furthermore are associated with fatal diseases such as cancers, neurodegenerative diseases and viral pandemics. Pre-structured motifs (PreSMos) refer to transient local secondary structural elements present in the target-unbound state of IDPs. During the last two decades PreSMos have been steadily acknowledged as the critical determinants for target binding in dozens of IDPs. To date, the PreSMo concept provides the most convincing structural rationale explaining the IDP-target binding behavior at an atomic resolution. Here we present a brief developmental history of PreSMos and describe their common characteristics. We also provide a list of newly discovered PreSMos along with their functional relevance.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.513-513
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• 2015

정확한 유역 토양수분 정보는 홍수 예측의 정도를 크게 향상시키므로 공간 토양수분 정보를 획득하기 위하여 선진국에서는 위성 영상을 활용하여 토양수분을 관측하고 있다. 본 연구에서는 유럽우주기구 ESA(European Space Agency)에서 운영하는 SMOS(Soil Moisture and Ocean Salinity) L-band 토양수분 관측치와 일본 우주항공 연구개발 기구 JAXA(Japan Aerospace Exploration Agency)에서 운영하는 GCOM-W1 위성의 AMSR2(Advanced Microwave Scanning Radiometer 2) C-band 토양수분 자료를 비교 분석하였다. SMOS 토양수분, AMSR2 토양수분을 기상청 농업관측관서의 지상 관측 토양수분 자료와 비교한 그래프는 다음과 같다(Fig. 1). 상대적으로 깊은 관측심으로 인한 장점을 가짐에도 불구하고 RFI로 인한 L-band 토양수분 자료의 시공간 관측율이 C-band 토양수분자료에 비하여 낮아 활용성이 낮다. AMSR2 자료는 여름철을 제외한 모든 계절에 과소 추정하는 단점을 보이며 실제적 활용을 위해 지상자료와의 편이보정 과정이 필수적이라 판단된다.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.356-366
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• 2020

The accuracy of satellite-observed sea surface salinity (SSS) was evaluated in comparison with in-situ salinity measurements from ARGO floats and buoys in the seas around the Korean Peninsula, the northwest Pacific, and the global ocean. Differences in satellite SSS and in-situ measurements (SSS errors) indicated characteristic dependences on geolocation, sea surface temperature (SST), and other oceanic and atmospheric conditions. Overall, the root-mean-square (rms) errors of non-averaged SMOS SSSs ranged from approximately 0.8-1.08 psu for each in-situ salinity dataset consisting of ARGO measurements and non-ARGO data from CTD and buoy measurements in both local seas and the ocean. All SMOS SSSs exhibited characteristic negative bias errors at a range of -0.50- -0.10 psu in the global ocean and the northwest Pacific, respectively. Both rms and bias errors increased to 1.07 psu and -0.17 psu, respectively, in the East Sea. An analysis of the SSS errors indicated dependence on the latitude, SST, and wind speed. The differences of SMOS-derived SSSs from in-situ salinity data tended to be amplified at high latitudes (40-60°N) and high sea water salinity. Wind speeds contributed to the underestimation of SMOS salinity with negative bias compared with in-situ salinity measurements. Continuous and extensive validation of satellite-observed salinity in the local seas around Korea should be further investigated for proper use.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.132-147
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• 2016

In this study the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) sensor onboard the Soil Moisture Ocean Salinity (SMOS) and Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor onboard the Global Change Observation Mission-Water (GCOM-W1) based soil moisture retrievals were revised to obtain better accuracy of soil moisture and higher data acquisition rate over East Asia. These satellite-based soil moisture products are revised against a reference land model data set, called Global Land Data Assimilation System (GLDAS), using Cumulative Distribution Function (CDF) matching and regression approach. Since MIRAS sensor is perturbed by radio frequency interferences (RFI), the worst part of soil moisture retrieval, East Asia, constantly have been undergoing loss of data acquisition rate. To overcome this limitation, the threshold of RFI, DQX, and composite days were suggested to increase data acquisition rate while maintaining appropriate data quality through comparison of land surface model data set. The revised MIRAS and AMSR2 products were compared with in-situ soil moisture and land model data set. The results showed that the revising process increased correlation coefficient values of SMOS and AMSR2 averagely 27% 11% and decreased the root mean square deviation (RMSD) decreased 61% and 57% as compared to in-situ data set. In addition, when the revised products' correlation coefficient values are calculated with model data set, about 80% and 90% of pixels' correlation coefficients of SMOS and AMSR2 increased and all pixels' RMSD decreased. Through our CDF-based revising processes, we propose the way of mutual supplementation of MIRAS and AMSR2 soil moisture retrievals.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.112-115
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• 2012

현재 전 세계적으로 물 부족 현상이 대두되는 가운데 그 양상은 더욱 심해지고 있다. 이러한 물 부족 현상의 악화됨에 따라 수자원 관리의 중요성이 부각되고 있다. 효율적인 수자원의 관리를 위해서는 근본적으로 물 순환 과정인 수문현상의 이해가 필요하다. 수문현상은 증발산, 강우, 침투, 유출 등의 일련의 과정을 말하는 것으로 이를 해석하기 위해서는 많은 수문 인자들의 정확한 관측이 필요하다. 특히 지표와 대기간의 에너지 및 물의 교환에 대한 중요한 요소인 토양수분은 수문현상의 해석을 위해 필수적인 인자이다. 따라서 수문현상의 정확한 해석을 위해서는 토양수분의 관측이 필요하며, 이에 대한 많은 관측이 이루어져 왔다. 최근에는 원격탐사의 기술의 발달로 토양수분의 관측에 대해 시공간적인 장점을 가지는 인공위성을 이용하고 있다. 토양수분관측에 있어서 많은 위성들이 이용되고 있으나 대다수의 경우 발사시점이 오래되었으며, 현재 2009년 ESA (European Space Agency) 의 지구관측 미션의 일환으로 발사된 SMOS (Soil Moisture and Ocean Salinity) 가 이용기간이 남아있다. 단, SMOS는 한국을 포함한 동아시아 및 유럽지역에 대해 RFI (Radio Frequency Interference) 의 전파방해로 우리나라의 경우 토양수분 Product의 직접적인 이용이 어려운 실정이다. 이에 본 연구에서는 SMOS의 Product인 밝기온도를 이용하여 복원알고리즘을 통해 토양수분을 복원하였다. 또한 복원된 알고리즘의 정확성을 평가하기 위해 한반도의 지점관측된 토양수분 데이터를 이용하여 본 알고리즘을 검증하였다.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.187-193
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• 2022

The accurate detection of environmental and biomarker gas species has attracted increasing attention due to their broad applications, such as air quality monitoring, disease diagnosis, and explosive chemicals detection. To accurately detect target gas species using chemiresistive gas sensors, using nanocatalysts on semiconducting metal oxides (SMOs) is considered the most promising approach. This review summarizes recent studies on methods for nanocatalysts functionalization on SMOs to achieve the highly selective gas sensors. To this end, we discuss various nanocatalyst decorated metal oxide-based chemiresistive gas sensors and provide an insight to construct highly accurate gas sensors.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.187-187
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• 2015

인공위성을 이용한 토양수분의 측정은, 범지구적인 물순환 분석에 있어서, 수문학적인 인자들의 시공간적인 변화를 예측, 분석하는데 있어 가장 효율적인 방법으로 제안되어왔다. 현재 국/내 외 적으로 사용하는 토양수분 위성은 Soil Moisture and Ocean Salinity (SMOS), Advanced SCATerometer (ASCAT)이 많이 사용되고 있으며, 더불어 일본에서 최근에 발사 된 Advanced Microwave Scanning Radiomter 2 (AMSR2) 센서를 통한 토양수분도 데이터도 적극 활용 되고 있다. 각 위성은 토양수분을 산출 하는 알고리즘, 파장대 그리고 위성 통과 시간 등이 각기 다르므로, 이러한 위성의 데이터를 사용하기 위해서는 지점 데이터와의 검증이 필수적으로 필요하게 된다. 이에따라 본 연구에서는 위성 데이터와 Global Land Data Assimilation System (GLDAS)와의 비교를 통해 각 위성데이터의 동아시아 지역에서의 효용성을 평가하였다. 동아시아의 건조한 지역에서는 SMOS가 가장 좋은 토양수분 데이터 결과를 보여주었으며, 다른 많은 지역에서는 ASCAT이 우세한 결과를 보여주었다. 하지만 한반도 지역의 특정 지역에서는 AMSR2의 토양수분 값이 ASCAT을 뛰어넘는 좋은 결과를 보여주는 결과가 도출되었다. 추가적으로, SMOS의 경우 Radio Frequency Interference (RFI)의 영향으로 한반도지역 토양수분을 측정하는 것에는 많은 무리가 있음을 알 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.94-103
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• 1997

It is necesary that analog buffer circuit should drive an external load in the VLSI design such as switched capacitor efilter (SCF), D/A converter, A/d converter, telecommunicatin circuit, etc. The conventional CMOS buffer circuit have many probvlems according as CMOS technique. Firstly, Capacity of large load ar enot able to opeate well. The problem can be solve to use class AB stages. But large load are operated a difficult, because an element of existing CMOS has a quadratic functional relation with inptu and outut voltage versus output current. Secondly, whole circuit of dynamic rang edecrease, because a range of inpt and output voltages go down according as increasing of intergration rate drop supply voltage. In this paper suggests that new differential CMOS line driver make out of operating an external of large load. In telecommunication's chip case transmission line could be a load. It is necessary that a load operate line driver. The proposal circuit is planned to hav ea high generation power rnage of voltage with preservin linearity. And circuit of capability is inspected through simulation program (HSPICE).

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.31.4-32
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• 2008

The microwave instruments are used many areas of the space remote sensing and space science applications. The imaging radar of synthetic aperture radar (SAR) is well known microwave radar sensor for earth surface and ocean research. Unlike radar, microwave radiometer is passive instrument and it measures the emission energy of target, i.e. brightness temperature BT, from earth surface and atmosphere. From measured BT, the geophysical data like cloud liquid water, water vapor, sea surface temperature, surface permittivity can be retrieved. In this paper, the radiometer characteristics, system configuration and principle of BT measurement are described. Also the radiometer instruments TRMM, GPM, SMOS for earth climate, and ocean salinity research are introduce. As first korean microwave payload on STSAT-2, the DREAM (Dual-channels Radiometer for Earth and Atmosphere Monitoring) is described the mission, system configuration and operation plan for life time of two years. The main issues of DREAM unlike other spaceborne radiometers, will be addressed. The calibration is the one of main issues of DREAM mission and how it contribute on the space borne radiometer. In conclusion, the radiometer instrument to space science application will be considered.