• Molecules and Cells
• /
• v.37 no.1
• /
• pp.31-35
• /
• 2014

Induced pluripotent stem cells (iPSCs) are capable of unlimited self-renewal and can give rise to all three germ layers, thereby providing a new platform with which to study mammalian development and epigenetic reprogramming. However, iPSC generation may result in subtle epigenetic variations, such as the aberrant methylation of the Dlk1-Dio3 locus, among the clones, and this heterogeneity constitutes a major drawback to harnessing the full potential of iPSCs. Vitamin C has recently emerged as a safeguard to ensure the normal imprinting of the Dlk1-Dio3 locus during reprogramming. Here, we show that vitamin C exerts its effect in a manner that is independent of the reprogramming kinetics. Moreover, we demonstrate that reprogramming cells under 2i conditions leads to the early upregulation of Prdm14, which in turn results in a highly homogeneous population of authentic pluripotent colonies and prevents the abnormal silencing of the Dlk1-Dio3 locus.

• Journal of Nutrition and Health
• /
• v.23 no.6
• /
• pp.451-458
• /
• 1990

Lean and obese male spontaneously hypertensive(SHR/Mcc-cp) rats were fed a ground rat chow diet with or without 0.001% estrone added from 6 to 18 weeks of age. Urine samples were collected weekly with 24 hour fasting. Both control lean and obese rats showed significantly higher urinary protein than their estrone treated counterparts. Treatment with 0.001% estrone diet was found to reduced the proteinuria in the maturing lean and obese SHR/Mcc-cp rats. Peaks in urinary protein level were noted at 16 weeks of age in both lean and obese control rats. Both control and estrone treated lean rats showed higher proteinuria than the obese rats. Therefore, obesity does not appear to be a contributing factor to the proteinuria in young male SHR/Mcc-cp rats.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2019.05a
• /
• pp.451-454
• /
• 2019

In this paper, we propose a verifiable image transformation networks to transform face sketch to photo and vice versa. Face sketch-photo is very popular in computer vision applications. It has been used in some specific official departments such as law enforcement and digital entertainment. There are several existing face sketch-photo synthesizing methods that use feed-forward convolution neural networks; however, it is hard to assure whether the results of the methods are well mapped by depending only on loss values or accuracy results alone. In our approach, we use two Resnet encoder-decoder networks as image transformation networks. One is for sketch-photo and another is for photo-sketch. They depend on each other to verify their output results during training. For example, using photo-sketch transformation networks to verify the photo result of sketch-photo by inputting the result to the photo-sketch transformation networks and find loss between the reversed transformed result with ground-truth sketch. Likely, we can verify the sketch result as well in a reverse way. Our networks contain two loss functions such as sketch-photo loss and photo-sketch loss for the basic transformation stages and the other two-loss functions such as sketch-photo verification loss and photo-sketch verification loss for the verification stages. Our experiment results on CUFS dataset achieve reasonable results compared with the state-of-the-art approaches.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.12
• /
• pp.2239-2246
• /
• 2008

Engine control/performance model for helicopter simulator if one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the engine designers/manufacturers. The approaches in this study were to develop the basic model bated on the available resources and to tune and verify it based on the ground/flight test results. The maintenance manuals of TB3-117 which is installed in KA-327 were reviewed and the components to be simulated for the engine control model were categorized and modeled. Piece-wise linear modeling method was used for the engine performance model. The engine performance data in the engine maintenance manuals were incorporated into the engine steady state performance tablet, which were incorporated with the transfer functions for the dynamic performance. Engine control/performance model was compared and tuned with the round/flight test results. It was verified that the fidelity of the model was within the tolerances in FAA AC120-63.

• Korean Journal of Remote Sensing
• /
• v.24 no.3
• /
• pp.223-233
• /
• 2008

In the mid 90's, the U.S. government released images acquired by the first generation of photo reconnaissance satellite missions between 1960 and 1972. The Declassified Intelligent Satellite Photographs (DISP) from the Corona mission are of high quality with an astounding ground resolution of about 2 m. The KH-4A panoramic camera system employed a scan angle of $70^{\circ}$ that produces film strips with a dimension of $55\;mm\;{\times}\;757\;mm$. Since GPS/INS did not exist at the time of data acquisition, the exterior orientation must be established in the traditional way by using control information and the interior orientation of the camera. Detailed information about the camera is not available, however. For reconstructing points in object space from DISP imagery to an accuracy that is comparable to high resolution (a few meters), a precise camera model is essential. This paper is concerned with the derivation of a rigorous mathematical model for the KH-4A/B panoramic camera. The proposed model is compared with generic sensor models, such as affine transformation and rational functions. The paper concludes with experimental results concerning the precision of reconstructed points in object space. The rigorous mathematical panoramic camera model for the KH-4A camera system is based on extended collinearity equations assuming that the satellite trajectory during one scan is smooth and the attitude remains unchanged. As a result, the collinearity equations express the perspective center as a function of the scan time. With the known satellite velocity this will translate into a shift along-track. Therefore, the exterior orientation contains seven parameters to be estimated. The reconstruction of object points can now be performed with the exterior orientation parameters, either by intersecting bundle rays with a known surface or by using the stereoscopic KH-4A arrangement with fore and aft cameras mounted an angle of $30^{\circ}$.

• Korean Journal of Social Welfare Studies
• /
• no.39
• /
• pp.147-165
• /
• 2008

This Study analysis two features of social citizenship in the period of rights revolution. Discousive arguments are derived from different reinterpretations of social citizenship of Marshall. Some insist that main idea of welfare state is rights of social citizenship and the other insist that social rights is realized after doing duty. Especially the latter emphasis work obligation in which individual responsibility and duty, these discussion underlie wokrfare policy. This reserch examine two contrary discourses based on Marshall's theory, and make a close inquiry into correct interpretation about Marshall. New rights, the Conservative party and New Labour seek for ground on Marshall's citizenship theory, but these are distortion on it. Marshall insisted that citizenship constituted rights and duties but he claimed that discharge of a duty isn't precondition of the exercise of the right.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.311-316
• /
• 2017

기후변화는 물 관리 측면에서 많은 변화를 일으키는 것으로 보고되고 있다. 주로 강우의 패턴을 변화시키며, 가용수자원의 지역적 편중을 심화시킨다. 기후변화에 적응하며 안정적이고 균등한 용수확보를 위해서는 홍수와 가뭄을 고려한 연속적인 물 순환 해석기술이 필요하다. 강우유출분석은 강우사상에 대한 수문순환과정을 통해 유출량을 산출하는 것으로, 주로 직접유출과 중간유출이 이에 해당된다. 강우발생 이후 무강우기간에 대해서는 기저시간 이후에 발생되는 유출량의 정량적 산출이 필요하다. 기저유출은 강우 발생 시점에 급격히 발생하기보다는 선행강우에 따른 유역 내 지하수위 분포와 대수층의 특성, 하천수위에 따라 다양한 패턴으로 나타나기 때문에 지하수대의 수리학적 성분들을 반영할 수 있어야 한다. 이를 위해서는 강우유출모의 시 지표유출량 산정과 지하수유동해석을 통한 기저유출량 산정이 동시에 이루어져야 한다. 최근 국내외에서는 다양한 형태의 수문모형과 MODFLOW를 연계한 장기유출분석에 대한 연구가 활발하게 진행되고 있다. 본 연구에서 활용한 K-DRUM(K-water Distribution Runoff Model)은 K-water에서 자체 개발한 물리적 기반의 분포형 강우유출모형으로 강우유출, 유사, 기초수질항목에 대한 3차원 분석이 가능하다. 본 모형의 A층(표층)은 지표유출을 고려한 운동파법이 적용되었고, B층과 C층(중간층), D층(지하수층)은 선형저류법이 적용되었다. MODFLOW(A Modular Three-Dimensional Finite-Difference Ground Water Flow Model)는 1980년대 USGS(United State Geolog ical Survey)에서 개발된 가장 범용적으로 사용되는 지하수유동모형이며, 모듈화 된 구조를 갖고 있어 다양한 패키지 중 필요로 하는 기능을 독립적으로 모의할 수 있는 장점이 있다. 본 연구에서는 향후 기후변화에 따른 강우의 불확실성에 대비한 유역의 장기 물순환 해석을 위해 강우유출모형인 K-DRUM과 지하수유동모형인 MODFLOW를 연계하고자한다. 연계방법은 K-DRUM에서 계산된 D층으로 침루되는 양을 MODFLOW의 함양량으로 적용하고, MODFLOW에서 산출된 기저유량을 K-DRUM의 하천유출에 적용하는 것이다. 본 연구의 성과를 갈수기 유출해석에 적용하면 정확성을 크게 향상시킬 수 있을 것으로 판단된다.

• Steel and Composite Structures
• /
• v.13 no.6
• /
• pp.501-519
• /
• 2012

As an alternative to current conventional force-based assessment methods, the energy-based seismic performance of a code-designed 20-storey high-rise steel building is evaluated in this paper. Using 3D nonlinear dynamic time-history method with consideration of additional material damping effect, the influences of different restoring force models and P-${\Delta}/{\delta}$ effects on energy components are investigated. By combining equivalent viscous damping and hysteretic damping ratios of the structure subjected to strong ground motions, a new damping model, which is amplitude-dependent, is discussed in detail. According to the analytical results, all energy components are affected to various extents by P-${\Delta}/{\delta}$ effects and a difference of less than 10% is observed; the energy values of the structure without consideration of P-${\Delta}/{\delta}$ effects are larger, while the restoring force models have a minor effect on seismic input energy with a difference of less than 5%, but they have a certain effect on both viscous damping energy and hysteretic energy with a difference of about 5~15%. The paper shows that the use of the hysteretic energy at its ultimate state as a seismic design parameter has more advantages than seismic input energy since it presents a more stable value. The total damping ratio of a structure consists of viscous damping ratio and hysteretic damping ratio and it is found that the equivalent viscous damping ratio is a constant for the structure, while the equivalent hysteretic damping ratio approximately increases linearly with structural response in elasto-plastic stage.

• Journal of the Korean Magnetics Society
• /
• v.17 no.3
• /
• pp.114-119
• /
• 2007

The single crystal $Nd_3Se_4$ with the $bcc-Th_3P_4$ type structure is grown and the temperature dependent magnetic susceptibilities are measured between 4 K and 300 K. The experimental data are compared with the theoretically calculated susceptibilities which depend on the splitting energies of the $Nd^{3+}$ ground state under the crystal field effect. We find that the magnetic susceptibility of the $Nd^{3+}$ ion in $Nd_3Se_4$ is not affected by the crystal field effect. The spontaneous magnetization curve below $T_c\;=\;53\;K$ of $Nd_3Se_4$ corresponds to the Brillouin function of $Nd_3Se_4$ with J=9/2.

• Geomechanics and Engineering
• /
• v.17 no.6
• /
• pp.507-513
• /
• 2019

Reinforced soil and Expanded Polystyrenes (EPS) mixture (RSEM) is a geomaterial which has many merits, such as light weight, wide strength range, easy for construction, and economic feasibility. It has been widely applied to improve soft ground, solve bridge head jump, fill cavity in pipeline and widen highway. Reutilizing dredged sediment to produce RSEM as earthfill can not only consume a large amount of waste sediment but also significantly reduce the construction cost. Therefore, there is an urgent need understand the basic stress-strain characteristics of reinforced dredged sediment-EPS mixture (RDSEM). A series of cyclic triaxial tests were then carried out on the RDSEM and control clay. The effects of cement content, EPS beads content and confining pressure on the cyclic stress-strain behaviour of RDSEM were analyzed. It is found that the three stages of dynamic stress-strain relationship of ordinary soil, vibration compaction stage, vibration shear stage and vibration failure stage are also applicative for RDSEM. The cyclic stress-strain curves of RDSEM are lower than that of control clay in the vibration compaction stage because of its high moisture content. The slopes of backbone curves of RDSEMs in the vibration shear stage are larger than that of control clay, indicating that the existence of EPS beads provides plastic resistance. With the increase of cement content, the cyclic stress-strain relationship tends to be steeper. Increasing cement content and confining pressure could improve the cyclic strength and cyclic stiffness of RDSEM.