• Journal of the Korean earth science society
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• v.42 no.4
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• pp.445-458
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• 2021

Gravity Recovery and Climate Experiment (GRACE) gravimeter satellites observed the Earth gravity field with unprecedented accuracy since 2002. After the termination of GRACE mission, GRACE Follow-on (GFO) satellites successively observe global gravity field, but there is missing period between GRACE and GFO about one year. Many previous studies estimated terrestrial water storage (TWS) changes using hydrological models, vertical displacements from global navigation satellite system observations, altimetry, and satellite laser ranging for a continuity of GRACE and GFO data. Recently, in order to predict TWS changes, various machine learning methods are developed such as artificial neural network and multi-linear regression. Previous studies used hydrological and climate data simultaneously as input data of the learning process. Further, they excluded linear trends in input data and GRACE/GFO data because the trend components obtained from GRACE/GFO data were assumed to be the same for other periods. However, hydrological models include high uncertainties, and observational period of GRACE/GFO is not long enough to estimate reliable TWS trends. In this study, we used convolutional neural networks (CNN) method incorporating only climate data set (temperature, evaporation, and precipitation) to predict TWS variations in the missing period of GRACE/GFO. We also make CNN model learn the linear trend of GRACE/GFO data. In most river basins considered in this study, our CNN model successfully predicts seasonal and long-term variations of TWS change.

• 대한생식의학회:학술대회논문집
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• 2001.06a
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• pp.80.1-80.1
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• 2001

• Korean Journal of Remote Sensing
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• v.22 no.4
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• pp.255-264
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• 2006

GRACE (Gravity Recovery and Climate Experiment) is the first dedicated gravity mapping mission. Its primary measurements are the distance changes between two co-orbiting low earth satellites. GRACE is a joint development by NASA and German DLR and was launched in March 2002. GRACE improves the Earth gravity model accuracy by nearly two factor of magnitude over pre-launch models. After brief description of the GRACE primary instrument, inter-satellite ranging system, its flight status and preliminary performance evaluation is presented. Ranging system error models, which were not included in the pre-launch performance model and design specifications, are identified through analyzing the flight data. Base on this analysis, future research topics on the GRACE instrument performance analysis are discussed.

• Journal of the Korean earth science society
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• v.35 no.7
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• pp.537-542
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• 2014

The Gravity Recovery and Climate Experiment (GRACE) has observed the Earth's mass redistribution mainly caused by the variations of groundwater, ice sheet, and sea level since its launch in April 2002. The global gravity model estimated by the GRACE observation is corrected by barometric pressure, and thus represents the change of Earth mass on the Earth's surface and below Earth's surface excluding air mass. However, the total air mass varies due to the water exchange between the Earth's surface and the atmosphere. As a result, the nominal GRACE gravity model should include the Earth's gravity spectrum associated with the total air mass variations, degree 0 and order 0 coefficients of spherical harmonics ($C_{00}$). Because the water vapor content varies mainly on a seasonal time scale, a change of $C_{00}$ (${\delta}C_{00}$) is particularly important to seasonal variations of sea level, and mass balance between northern and southern hemisphere. This result implies that ${\delta}C_{00}$ coefficients should be accounted for the examination of continental scale mass change possibly associated with the climate variations.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.109-112
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• 2006

2002년 발사 된 GRACE (Gravity Recovery and Climate Experiment)는 미국과 독일 합작으로 개발된 지구중력장 측정 전용 위성으로 동일한 궤도를 비행하는 두 개의 위성 사이 거리 변화를 측정하여 지구 중력장을 추정하는 사업이다. GRACE 위성의 핵심 관측기인 위성간 거리측정기의 원리에 대해 소개하고, 운용 현황 및 성능에 대해 소개하였다. 발사 전 성능 분석 단계에서 고려되지 못했던 거리측정기 오차 요인에 대해 분석하고, 향후 연구 방향을 제시하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.5
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• pp.513-518
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• 2008

The research of global-scale mass redistribution and it changed by Earth gravity filed variation observations, including Earth's oblateness $J_2$(also called low degree spherical harmonic coefficient $C_{20}$), is in continuous progress. Recently, the comparative analysis of geodetic observation SLR can be made by the development of GRACE and other time-variable gravity measurements. In this study, $C_{20}$ time series changes in the value of comparative analysis was got by GRACE monthly Gravity filed model (CSR RL04) for the period April 2002 to May 2008. And comparative analysis the harmonic coefficients of $C_{20}$ was obtained from SLR observations. Signal analysis for two time-series data was made by wavelet transform, CWT(continuous wavelet transform), XWT(cross wavelet transform) and WTC(wavelet coherence) methods. The results indicate that GRACE and SLR values for $C_{20}$ had both decreasing trend, as well as SLR data represent the annual frequencies, and GRACE was semiannual variations. In addition, the results of GRACE and SLR had a strong correlation with the XWT and WTC in an annual cycle.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.265-277
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• 2019

Changes in the amount, intensity, frequency, and type of precipitation, in conjunction with global warming and climate change, critically impact groundwater recharge and associated groundwater level fluctuations. Monthly gravity levels by the Gravity Recovery and Climate Experiment (GRACE) are acquired to monitor total water storage changes at regional and global scales. However, there are inherent difficulties in quantitatively relating the GRACE observations to groundwater level data due to the difficulties in spatially representing groundwater levels. Here three local interpolation methods (kriging, inverse distance weighted, and natural neighbor) were implemented to estimate the areal distribution of groundwater recharge changes in South Korea during the 2002-2016 period. The interpolated monthly groundwater recharge changes are compared with the GRACE-derived groundwater storage changes. There is a weak decrease in the groundwater recharge changes over time in both the GRACE observations and groundwater measurements, with the rate of groundwater recharge change exhibiting mean and median values of -0.01 and -0.02 cm/month, respectively.

• Journal of Fashion Business
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• v.9 no.4
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• pp.30-43
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• 2005

The purpose of this study is to examine the ladylike style of Grace Kelly focusing on her costume design of 1950s movie and star image, and to understand how she became a fashion icon today. Her city elegant look was usually composed of A line or H line suits and dresses, pearl jewelry, gloves, handbags and her classic ladylike attitude. Kelly's luxury casual look epitomized a relaxed elegance based on the American sporting image including the Hermes "Kelly" bag. Her sexual elegant look showed the combination of freshness, ladylike virtue and underlying sex appeal. Her self-confident, ladylike style appeals to modern fashionable women who likes to be elegant but also sexy.

• Journal of English Language & Literature
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• v.54 no.4
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• pp.511-530
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• 2008

In "A Good Man Is Hard to Find," Flannery O'Connor describes a striking journey of a family, in which all the members dramatically get killed. Through the tragic death of Bailey's family, O'Connor evokes the reader to think about life and the life after death. Growing up in the communities of Catholicism and Protestantism, O'Connor herself had agonized with the same question between the two types of Christian belief throughout her life. In the story, O'Connor embodies her anguish with the major characters and questions the reader about the meaning of Christian salvation. More specifically, Bailey's family represent the people who get lost in life. They live without any direction and purpose. Red Sammy and his wife, on the other hand, provide travellers with rest, food, and the necessaries. The Tower is a shelter of travellers in life; however, it is not everlasting but temporary. The Misfit, exemplifying religious stragglers, has been completely frustrated with the variance of Christian salvation theories, and no longer practices the religion but knows enough to justify his cruel behaviors. Finally, the grandmother is the manipulator and opportunist of the religion. All those characters are fragments of human characters and their life - obscene and transitory. In the story, there is little God's grace on the surface even though the writer claims "all my stories are about the action of grace." Nonetheless, the reader should be able to identify with those characters because they are the mirror images of themselves. While visualizing the characters, O'Connor wants the reader to have a moment to think about the "Righteousness," and ultimately to seek out God's grace that she essentially wishes to show the reader. Instead of showing God's grace directly, O'Connor ultimately leads the reader to consider about God and the grace as she/he reads the work.

• Archives of Plastic Surgery
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• v.42 no.2
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• pp.126-130
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• 2015

Lipofilling is a reconstructive and aesthetic technique that has recently grown in popularity and is increasingly being used in breast surgery. Previous concerns had been raised regarding its safety when used for remodelling and reconstruction of the breast; however, these concerns have since been dismissed. Over the subsequent two decades, little evidence has been found to support these early theoretical concerns, and growing numbers of proponents of the procedure are confident in its safety. Many developments and refinements in the technique have taken place in recent years, and several studies have been published regarding the safety of lipofilling in the breast. We reviewed the current literature regarding the use of different lipofilling techniques as well as the current evidence regarding the oncological safety of the procedure in patients seeking aesthetic breast enhancement and in patients requiring reconstruction after treatment for breast cancer.