• 천문학회보
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• 제39권2호
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• pp.62.1-62.1
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• 2014

Metallicity distribution of globular clusters (GCs) provides an important clue for star formation history of their host galaxy. With an assumption that GCs are generally old, GC colors have been used as a proxy of GC metallicities. Bimodal GC color distributions observed in most large galaxies have, for decades, been interpreted as bimodal metallicity distributions, indicating the presence of two populations within a galaxy. However, the conventional view has been challenged by a new theory that non-linear GC color-metallicity relations (CMRs) can cause a bimodal color distribution even from a single-peaked metallicity distribution. Using the photometric and spectroscopic data of NGC 5128 GCs in combination with stellar population simulation models, we examine the effect of non-linearity in GC CMRs on the transformation of GC color distributions into metallicity distributions. Although, in some colors, offsets are present between observations and models in the CMRs, their overall shape agrees well for various colors. After the offsets are corrected, the observed spectroscopic metallicity distribution is well reproduced via modeled CMRs from various color distributions having different morphologies. On the other hand, the linearly converted metallicity distributions from GC colors show a significant discrepancy with the observed spectroscopic metallicity distribution. We discuss the implications of our results.

• 대한원격탐사학회지
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• 제35권6_1호
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• pp.987-997
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• 2019

최근 무인항공기(UAV)의 발전과 관심이 높아지면서 UAV의 수요가 급증하고 있다. 전통적인 방식의 인공위성 및 항공영상에 비해 적은 운용비용으로 효과적인 자료 취득이 가능하여 다양한 연구(환경, 지리정보, 해양관측, 원격탐사)에 활용되고 있다. 다만, 배터리 용량 및 관제시스템과 기체의 거리 제한에 따라 전통적인 원격탐사 방법인 위성과 항공기를 이용한 방법에 비해 좁은 면적만을 획득한다는 단점이 있다. 하지만 원거리 원격관제가 가능하다면 원격탐사 분야에서의 UAV의 활용 가능성은 더 높아질 수 있으며 이에 UAV와 관제 시스템의 거리에 상관없이 관제할 수 있는 통신 네트워크 시스템이 필요하다. 전통적인 방식의 무선장치(RF 2.4 GHz, 915 MHz, 433 MHz)로 UAV와 Ground Control System(GCS)가 송수신 할 수 있는 거리는 약 2 km 내외로 제한적이다. 하지만 구축되어 있는 Long-Term Evolution(LTE) 통신망 기반의 제어방식을 적용하면 Radio Frequency(RF) 통신망의 단점을 보완할 수 있어 기존 산업과 융합하여 보다 큰 효과를 이룰 수 있다. 본 연구에서는 LTE 통신방식을 통해 GCS 기준 최대 직선거리 6.1 km, 촬영 면적 2.2 ㎢, 총 비행 거리 41.75 km의 비행을 수행하였다. 또한, LTE 통신의 무선 기지국 현황을 통해 통신 두절 가능성에 대해서도 분석하였다.

• Fibers and Polymers
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• 제7권4호
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• pp.389-397
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• 2006

The beneficial effects of graduated compression stockings (GCS) in prophylaxis and treatment of venous disorders of human lower extremity have been recognized. However, their pressure functional performances are variable and unstable in practical applications, and the exact mechanisms of action remain controversial. Direct surface pressure measurements and indirect material properties testing are not enough for fully understanding the interaction between stocking and leg. A three dimensional (3D) biomechanical mathematical model for numerically simulating the interaction between leg and GCS in dynamic wear was developed based on the actual geometry of the female leg obtained from 3D reconstruction of MR images and the real size and mechanical properties of the compression stocking prototype. The biomechanical solid leg model consists of bones and soft tissues, and an orthotropic shell model is built for the stocking hose. The dynamic putting-on process is simulated by defining the contact of finite relative sliding between the two objects. The surface pressure magnitude and distribution along the different height levels of the leg and stress profiles of stockings were simulated. As well, their dynamic alterations with time processing were quantitatively analyzed. Through validation, the simulated results showed a reasonable agreement with the experimental measurements, and the simulated pressure gradient distribution from the ankle to the thigh (100:67:30) accorded with the advised criterion by the European committee for standardization. The developed model can be used to predict and visualize the dynamic pressure and stress performances exerted by compression stocking in wear, and to optimize the material mechanical properties in stocking design, thus, helping us understand mechanisms of compression action and improving medical functions of GCS.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.61-61
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• 2003

We have cloned the CGR1 gene encoding glutathione reductase (GR) which catalyzes the reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH) from Candida albicans. The cgr1/cgr1 mutants were not viable when CaMAL2 promoter repressed the CGR1 expression. The growth of the mutants could be partially overcome by thiol compounds such as GSH, dithiothreitol, cysteine, N-acetylcysteine and GSSG. Interestingly, C. albicans with CGR1 overexpressed showed defective hyphal growth on solid medium and attenuated virulence. We have also cloned the GCS1 gene encoding ${\gamma}$-glutamylcysteine synthetase which catalyzes the first step of glutathione biosynthesis. The gcs1/gcs1 mutants were nonviable in minimal defined medium. The growth of the mutants could be resumed by supplementing with GSH, GSSG and ${\gamma}$-glutamylcysteine in the medium. The mutants had increased intracellular D-erythroascorbic acid level up to 2.25-fold when transferred to GSH-free medium. When the mutants were depleted of GSH, they showed typical markers of apoptosis. In conclusion, these results suggest that glutathione is an essential metabolite, and involved in hyphal growth, virulence and apoptosis in C. albicans.

• Journal of Platform Technology
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• 제10권4호
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• pp.56-61
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• 2022

제4차 산업혁명을 통하여 발견된 다양한 융합기술은 산업에 스며들고 있다. 드론은 융합기술을 기반으로 건설, 교통, 국방 등의 산업에서 활용되고 있다. 회전익 드론 조종은 눈으로 보며 동작시키는 가시권에서부터 GCS를 활용한 원격지 비 가시권까지 다양한 범위에서 활용되고 있다. 산업용 드론을 운영하는 관계자를 분류하면 드론을 직접 활용하는 일반 조종자, 드론 조종자를 양성하는 교관, 드론의 상태를 점검하고 장기간 활용할 수 있게 하는 정비사 등이 있다. 드론 GCS의 화면은 어떠한 형태로 나타나느냐에 따라서 사용자의 빠른 대응, 또는 핵심적인 데이터를 획득할 수 있다. 이에 따라 본 연구에서는 미션플래너 GCS를 대상으로 GUI 특성을 분석하여 사용자에 따른 화면 구성방안을 설계하였다.

• 생명과학회지
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• 제12권3호
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• pp.317-324
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• 2002

흰쥐 발정주기와 난소절제에 따른 질의 GCs, ER-$\alpha$, c-fos 및 c-jun 변화를 조직화학적 및 면역조직화학적으로 관찰하였다. 질상피는 발정사이기와 발정전기로 이어 지는 점액세포화과정에서 현저한 GCs의 양적 증가를 관찰할 수 있으며 발정사이기의 SBA, 발정전기와 발정기의 Con A와 같이 발정주기에 따른 특이적 GCs가 관찰되었다. 난소절제시에는 매우 위축된 표면층 평평세포에서만 미량의 GCs가 관찰되었다. 질에서 ER-$\alpha$, c-fos, c-jun등은 주로 핵에서 반응을 나타내는데, ER- $\alpha$는 상피세포 중 바닥층에서 주로 관찰되며, 반응세포수로 보아 발정주기에 따른 변화는 없었으나 버팀질세포에서는 발정사이기부터 발정기사이에 가장 많이 관찰되었다. c-fos는 상피의 바닥층과 중간층세포 그리고 버팀질세포에서 발정전기와 발정기사이에 가장 많이 관찰되며 c-jun은 발정기의 상피 바닥층에서 가장 많이 관찰되나 버팀질세포에서는 발정기에만 관찰되었다. 난소절제시 ER-$\alpha$, c-fos, c-jun모두 상피의 적은 세포에서만 관찰되며 버팀질 세포에서는 관찰되지 않았다. 이상의 결과로 보아 발정주기와 난소절제에 따라 특이적인 GCs분포를 보일 뿐 아니라 ER-$\alpha$, c-fos, c-jun 같은 단백질의 상이한 분포를 보여 주고 있어 이들이 질상피세포의 증식과 분화에 관여함을 알 수 있다.

• Journal of Korean Neurosurgical Society
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• 제30권2호
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• pp.207-210
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• 2001

Objective : The prognosis of spontaneous intracerebral hemorrhage often depends on initial neurologic condition, size and location of hemorrhage and associated intraventricular hemorrhage. However, age of patient, coagulation state and other associated vascular diseases may also play a role when present. In recent years, the geriatric population has been increasing. The age distribution of the patients with intracerebral hemorrhages also has been increased, accordingly. However, such patients, especially when associated with poor initial conditions often tend to be managed rather conservatively. The authors analyzed retrospectively on forty-five patients with spontaneous intracerebral hemorrhage over the seventies with poor initial condition to find out whether there exists a difference of outcome between surgery and non-surgery group. Material and Method : A total of 45 patients over seventies with spontaneous intracerebral hemorrhage with Glasgow Coma Scale(GCS) 4-8 treated over last six years were included. The validity of surgical management for these patients as well as clinical variables which might have been operated on the outcome of these patients were evaluated. The Glasgow Outcome Scale(GOS) after three months was used for comparison of outcome. Results : In surgical group(19 cases), mean age was 74.5 years old, mean hematoma volume 67.2ml and mean GCS score 5.7 points. In nonsurgical group(26 cases), mean age was 79.3 years old, mean hematoma volume 32.1ml, and mean GCS score 6.8 points. Mortality rate in surgical group was 47.4%(9 patients), including 2 cases of post-operative rebleeding, while that in nonsurgical group was 46.2%. However, when patients with initial GCS 4-6 points and over 30ml in hematoma volume were regrouped, mortality rate in surgical group was 46.2%, whereas mortality rate in nonsurgical group was 66.7%. Conclusion : It is concluded that the mortality rate is much low in surgery group with initial GCS less than 6 points and hematoma volume over 30cc. There was no significant difference of outcome in patients with basal ganglia and thalamic hemorrhage. However, surgical treatment lowered the mortality and morbidity rate in patients with subcortical and cerebellar hemorrhage.

• 한국정보전자통신기술학회논문지
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• 제15권6호
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• pp.457-462
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• 2022

최근 드론을 엔터테인먼트 도구로 이용하는 문화생활이 다양하게 만들어지고 있고, 이를 실현하기 위해 비행 금지 구역을 침범할 정도로 성능이 좋은 드론을 이용하는 사용자가 많아지고 있다. 만족도가 높은 엔터테인먼트 활동을 위한 드론은 체공 시간도 길어야 하고 장거리 비행도 가능해야 하는데, 이것이 종종 비행 금지구역을 침범하거나 또는 원하지 않는 비행 충돌 문제가 발생하여 큰 피해가 날 수 있다. 본 연구에서는 이러한 문제를 해결하기 위하여 GCS(Ground Control System)로 비행 금지구역을 설정하고, 임계속도 10km/h 이하로 비행할 경우 비행 금지구역으로부터 10m 떨어진 임계거리 안으로 들어오지 않게 하여 안전하게 드론을 조종하게 하고, 임계속도 이상으로 비행해서 임계거리 안으로 진입할 경우 드론이 GCS 제어에 의해 self-drop 하도록 하여 비행 금지구역 안으로 들가지 못하도록 하는 방법을 제안하였다. 제안한 방법으로 특정 실험 지역에서 총 44번의 반복실험을 한 결과 한두번 제한구역을 넘어간 경우를 제외하고는 드론이 안전하게 self-drop한 결과를 얻었으며 제안한 방법으로 드론을 제어할 경우 비행 금지구역으로 넘어가는 것을 막을 수 있는 적절한 방법임을 확인할 수 있었다.

• 천문학회보
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• 제38권2호
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• pp.62.2-62.2
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• 2013

Recent spectroscopic observations have provided evidence for complex chemical evolution by supernovae and/or asymptotic giant branch (AGB) stars in the two metal-poor globular clusters (GCs) NGC2419 and M15. In particular, the horizontal branches (HBs) of these metal-poor GCs are very extended in the Hertzsprung-Russell diagram. The origin of these peculiar features, as well as that for the Sandage period-shift effect observed in these clusters, are yet to be understood. Here we show, by constructing population models including the Nitrogen enhanced subpopulation, that the second generation populations in these clusters would be enhanced not only in Helium, but also in Nitrogen. This working hypothesis can simultaneously explain the observed extended feature on the HB and the period-shift of RR Lyrae variables.

• Asian-Australasian Journal of Animal Sciences
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• 제33권6호
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• pp.879-887
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• 2020

Objective: Numerous studies have indicated that the apoptosis and proliferation of granulosa cells (GCs) are closely related to the normal growth and development of follicles and ovaries. Previous evidence has suggested that miR-126-3p might get involved in the apoptosis and proliferation of GCs, and phosphatidylinositol 3-kinase regulatory subunit 2 (PIK3R2) gene has been predicted as one target of miR-126-3p. However, the molecular regulation of miR-126-3p on PIK3R2 and the effects of PIK3R2 on porcine GCs apoptosis and proliferation remain virtually unexplored. Methods: In this study, using porcine GCs as a cellular model, luciferase report assay, mutation and deletion were applied to verify the targeting relationship between miR-126-3p and PIK3R2. Annexin-V/PI staining and 5-ethynyl-2'-deoxyuridine assay were applied to explore the effect of PIK3R2 on GCs apoptosis and proliferation, respectively. Real-time quantitative polymerase chain reaction and Western Blot were applied to explore the regulation of miR-126-3p on PIK3R2 expression. Results: We found that miR-126-3p targeted at PIK3R2 and inhibited its mRNA and protein expression. Knockdown of PIK3R2 significantly inhibited the apoptosis and promoted the proliferation of porcine GCs, and significantly down-regulated the mRNA expression of several key genes of PI3K pathway such as insulin-like growth factor 1 receptor (IGF1R), insulin receptor (INSR), pyruvate dehydrogenase kinase 1 (PDK1), and serine/threonine kinase 1 (AKT1). Conclusion: MiR-126-3p might target and inhibit the mRNA and protein expressions of PIK3R2, thereby inhibiting GC apoptosis and promoting GC proliferation by down-regulating several key genes of the PI3K pathway, IGF1R, INSR, PDK1, and AKT1. These findings would provide great insight into further exploring the molecular regulation of miR-126-3p and PIK3R2 on the functions of GCs during the folliculogenesis in female mammals.