• 한국지리정보학회지
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• 제3권4호
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• pp.63-72
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• 2000

본 연구의 목적은 GIS와 RS(Landsat TM, KOMPSAT EOC) 데이터를 이용한 AGNPS(Agricultural Nonpoint Source Pollution) 모형의 적용성을 판단하기 위한 것이다. AGNPS 모형은 잘 알려진 분포형 강우사상 모형으로써 이 모형은 밭의 시비수준과 축산농가의 오염 부하 수준을 적용할 수 있어 이를 효율적으로 관리할 수 있는 방법을 평가 할 수 있다. 본 연구의 대상 유역은 경기도 안성군 고산면(정동리, 야동리, 쌍령리)에 위치하고, 20개의 소규모 축산 농가가 산재해 있는 면적 $4.12km^2$ 내에 소유역이다. AGNPS 모형의 입력 데이터는 Arc/Info, GRASS, ER-Mapper, Idrisi를 사용하여 구축되었다. 모형의 보정 및 검증을 위해 사용된 강우 자료는 1시간 간격으로 관측된 1999년의 4개의 강우사상(5월 18일, 7월 29일, 9월 10일, 9월 20일)을 사용하였고, 수질 측정은 4개의 지점에서 측정된 실측자료를 사용하였다.

• Asia Marketing Journal
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• 제14권1호
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• pp.1-24
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• 2012

본 연구는 고객만족과 기업가치 성과간의 관계를 분석하는 것이 목적이다. 기업가치성과는 주가와 신용등급으로 나눌 수 있는데, 전자는 기업의 시장가치이고 후자는 자금조달비용이라 구분하여 사용되고 있다. 고객만족과 주가와의 관계는 비교적 오래전부터 연구되어 왔으나 신용등급과의 관계는 최근 들어 연구되기 시작하였다. 대표적으로 Anderson and Mansi(2009)의 연구에서는 양자가 긍정적으로 관련된 것으로 밝혀졌으나, 윤상운(2010)이 국내자료를 사용한 연구에서는 그 관계가 입증되지 못하였다. 일치하지 않는 두 연구의 결과에서 아이디어를 얻어 본 연구에서는 고객만족이 신용등급에 긍정적 영향을 미치는 것으로 보고 이를 검증하였다. 두 연구에서 사용한 모델을 참고로 하였고 특히 우리나라 실정에서는 정부지원이 중요한 변수임을 감안하여 이를 포함한 연구모형을 설정하여 검증한 결과 긍정적 관련성이 있는 것으로 나타났다. 추가분석에서 자산규모가 큰 기업보다 작은 기업에서, 제조업보다 서비스업에서 고객만족이 신용등급에 더 유의한 긍정적 영향을 미치는 것으로 나타났다.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.401-406
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• 2021

최근 들어, 음향 이벤트 검출을 위하여 CRNN(: Convolutional Recurrent Neural Network) 구조에 기반 한 평균-교사 모델이 대표적으로 사용되고 있다. 평균-교사 모델은 두 개의 병렬 형태의 CRNN을 가진 구조이며, 이들의 출력들의 일치성을 학습 기준으로 사용함으로서 약-전사 레이블(label)과 비-전사 레이블 음향 데이터에 대해서도 효과적인 학습이 가능하다. 본 연구에서는 최신의 평균-교사 모델에 로그-멜 스펙트럼에 대한 차분 특징을 추가적으로 사용함으로서 보다 나은 성능을 이루고자 하였다. DCASE 2018/2019 Challenge Task 4용 학습 및 테스트 데이터를 이용한 음향 이벤트 검출 실험에서 제안된 차분특징을 이용한 평균-교사모델은 기존의 방식에 비해서 최대 8.1%의 상대적 ER(: Error Rate)의 향상을 얻을 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.784-787
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• 2003

Electrorheological(ER) and magnetorheological(MR) fluid-based dampers are typically analyzed using Bingham-plastic shear model under quasi-steady fully developed flow conditions. A Herschel-Bulkley constitutive shear flow relationship is that the linear shear stress vs. strain rate behavior of Bingham model is replaced by a shear stress that is assumed to be proportional to a power law of shear rate. This power is called the flow behavior index. Depending on the value of the flow behavior index number, varying degrees of post-yield shear thickening or thinning behavior can be analyzed. But it is not practical to analyze the damping force in a flow mode damper using Herschel-Bulkley model because it is needed to solve a polynomial equation. A useful guide is suggested to analyze the damping force in a damper using the Herschel-Bulkley model.

• 한국조명전기설비학회지:조명전기설비
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• 제13권2호
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• pp.234-234
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• 1999

The aim of this paper is to suggest a design method of the optimal model following control system using genetic algorithm (GA). This control system is designed by applying GA with reference model to the optimal determination of weighting matrices Q, R that are given by LQ regulator problem. The method to do this is that all the diagonal elements of weighting matrices are optimized simultaneously by GA, in the search domain selected adequately. And we design the model following control system to boi1er-turbine equipment by the proposed method. The model following control system designed by this method has the better command tracking performance than that of the control system designed by the trial-and-error method. The effectiveness of this control system is verified by computer simulation.

• BMB Reports
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• 제51권9호
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• pp.450-455
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• 2018

Tamoxifen (TAM) is commonly used to treat estrogen receptor (ER)-positive breast cancer. Despite the remarkable benefits, resistance to TAM presents a serious therapeutic challenge. Since several HOX transcription factors have been proposed as strong candidates in the development of resistance to TAM therapy in breast cancer, we generated an in vitro model of acquired TAM resistance using ER-positive MCF7 breast cancer cells (MCF7-TAMR), and analyzed the expression pattern and epigenetic states of HOX genes. HOXB cluster genes were uniquely up-regulated in MCF7-TAMR cells. Survival analysis of in slico data showed the correlation of high expression of HOXB genes with poor response to TAM in ER-positive breast cancer patients treated with TAM. Gain- and loss-of-function experiments showed that the overexpression of multi HOXB genes in MCF7 renders cancer cells more resistant to TAM, whereas the knockdown restores TAM sensitivity. Furthermore, activation of HOXB genes in MCF7-TAMR was associated with histone modifications, particularly the gain of H3K9ac. These findings imply that the activation of HOXB genes mediate the development of TAM resistance, and represent a target for development of new strategies to prevent or reverse TAM resistance.

• Journal of Korean Dental Science
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• 제10권2호
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• pp.66-73
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• 2017

Purpose: To evaluate the effect of different-sized drill tips and laser irradiation times on the initial stability of orthodontic miniscrews placed in Er,Cr:YSGG-laser pre-drilled holes in an animal model. Materials and Methods: Laser pre-drilled holes were made in dog mandibular bone with an Er,Cr:YSGG laser using irradiation times of 5, 7, 9, 11, and 13 seconds, and tip diameters of 0.4 and 0.6 mm. The maximum diameter and depth of the pre-drilled holes was measured with micro computed tomography. The maximum insertion torque was measured during placement the miniscrew. Result: Laser pre-drilled holes were conical shaped. The maximum diameter of pre-drilled holes increased with longer laser irradiation times (P>0.05) and larger tip diameters (P<0.05). The depth of pre-drilled holes increased with longer laser irradiation times and larger tip diameters (P<0.05). When the 0.4 mm tip, but not the 0.6 mm tip, was used, the insertion torque decreased significantly with longer laser irradiation times (P<0.05). Conclusion: Tip diameter impacted insertion torque more than irradiation time. It takes at least 9 seconds using a 0.6 mm tip to create a 0.8 mm diameter and 1.0 mm depth hole in thick cortical bone.

• 한국음향학회지
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• 제30권2호
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• pp.63-72
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• 2011

본 논문은 반향음과 투과음을 감소시키기 위한 평판형 음향재료의 성능평가 장치를 제작하고 측정시스템을 구성하며 표준표적을 이용한 검증을 통해 신뢰성을 확보하는 데 목적이 있다. 반향음감소와 투과손실 측정은 신호간섭이 없도록 대형수조에서 실시되는 것이 일반적이지만, 본 논문에서는 신호간섭을 고려해야 하는 소형수조에서 최저 30 kHz까지 측정이 가능한 측정시스템을 구성하였다. 이를 위해 신호모의를 통해 신호간섭이 없는 최적의 기하학적 배치를 도출하였으며, 획득한 신호를 시간영역과 주파수영역의 총 네 가지 방법으로 ER과 TL을 도출하는 신호처리 알고리즘을 확립하였다. 마지막으로 대형수조에서의 전파손실 실측실험을 통해 측정시스템을 보정하고 알루미늄 판과 스티로폼을 표준표적으로 사용한 측정결과를 Brekhovskikh Layer Model과 비교하여 측정시스템 검증을 수행하였다.

• Biomolecules & Therapeutics
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• 제29권5호
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• pp.545-550
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• 2021

Chemotherapy-induced alopecia and hair loss can be stressful in patients with cancer. The hair grows back, but sometimes the hair tends to stay thin. Therefore, understanding mechanisms regulating hair regeneration may improve the management of chemotherapy-induced alopecia. Previous studies have revealed that chemotherapeutic agents induce a hair follicle vascular injury. As hair growth is associated with micro-vessel regeneration, we postulated that the stimulation of angiogenesis might enhance hair regeneration. In particular, mice treated with 5-fluorouracil (5-FU) showed delayed anagen initiation and reduced capillary density when compared with untreated controls, suggesting that the retardation of anagen initiation by 5-FU treatment may be attributed to the loss of perifollicular micro-vessels. We investigated whether the ETS transcription factor ETV2 (aka ER71), critical for vascular development and regeneration, can promote angiogenesis and hair regrowth in a 5-FU-induced alopecia mouse model. Tie2-Cre; Etv2 conditional knockout (CKO) mice, which lack Etv2 in endothelial cells, presented similar hair regrowth rates as the control mice after depilation. Following 5-FU treatment, Tie2-Cre; Etv2 CKO mice revealed a significant reduction in capillary density, anagen induction, and hair restoration when compared with controls. Mice receiving lentiviral Etv2 injection after 5-FU treatment showed significantly improved anagen induction and hair regrowth. Two-photon laser scanning microscopy revealed that enforced Etv2 expression restored normal vessel morphology after 5-FU mediated vessel injury. Our data suggest that vessel regeneration strategies may improve hair regrowth after chemotherapeutic treatment.

• Journal of Gastric Cancer
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• 제22권1호
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• pp.24-34
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• 2022

Purpose: Total gastrectomy (TG) with lymph node (LN) dissection is recommended for early gastric cancer (EGC) but is not indicated for endoscopic resection (ER). We aimed to identify patients who could avoid TG by establishing a scoring system for predicting lymph node metastasis (LNM) in proximal EGCs. Materials and Methods: Between January 2003 and December 2017, a total of 1,025 proximal EGC patients who underwent TG with LN dissection were enrolled. Patients who met the absolute ER criteria based on pathological examination were excluded. The pathological risk factors for LNM were determined using univariate and multivariate logistic regression analyses. A scoring system for predicting LNM was developed and applied to the validation group. Results: Of the 1,025 cases, 100 (9.8%) showed positive LNM. Multivariate analysis confirmed the following independent risk factors for LNM: tumor size >2 cm, submucosal invasion, lymphovascular invasion (LVI), and perineural invasion (PNI). A scoring system was created using the four aforementioned variables, and the areas under the receiver operating characteristic curves in both the training (0.85) and validation (0.84) groups indicated excellent discrimination. The probability of LNM in mucosal cancers without LVI or PNI, regardless of size, was <2.9%. Conclusions: Our scoring system involving four variables can predict the probability of LNM in proximal EGC and might be helpful in determining additional treatment plans after ER, functioning as a good indicator of the adequacy of treatments other than TG in high surgical risk patients.