보현산과 일본 Shigaraki 전천 카메라 화상의 대기 파동 비교

양태용,김정한,정종균,원영인,이방용,Shiokawa, K.,김용하 한국우주과학회 2007 한국우주과학회보 Vol.16 No.1

Fuzzy 계획법의 해법일반화에 관한 연구

梁泰瑢,金顯俊 한국경영과학회 1986 한국경영과학회지 Vol.11 No.1

In this study, the fuzzy programming is extended to handle various types of membership functions by transformation of the complicated fuzzy programming problems into the equivalent crisp linear programming problems with single objective. It is well-known that the fuzzy programming problem with linear membership function (i.e., ramp type) can be easily transformed into a linear programming problem by introducing one dummy variable to minimize the worst unwanted deviation. However, until recently not many researches have been done to handle various general type of complicated linear membership functions which might be more realistic than ramp-or triangular-type functions. In order to handle these complicated membership functions, the goal dividing concept, which is based on the fuzzy set operation (i.e., intersection and union operations), has been prepared. The linear model obtained using the goal dividing concept is more efficient and simple than the previous models [4, 8]. In addition, this result can be easily applied to any nonlinear membership functions by piecewise approximation since the membership function is continuous and monotone increasing or decreasing.

Characteristics of mid-latitude field-aligned irregularities observed with VHF coherent scatter ionospheric radar over Korea

양태용,곽영실,길효섭,박영득,Yang, Tae-Yong,Kwak, Young-Sil,Kil, Hyosub,Park, Young-Deuk 한국천문학회 2012 天文學會報 Vol.37 No.2

The 40.8-MHz VHF coherent scatter ionospheric radar, located in South Korea (Gyeryong, $36.18^{\circ}N$, $127.14^{\circ}E$), has been operating since December 2009 to investigate ionosphere E- and F-region field-aligned irregularities (FAIs) of mid-latitude. During the observation, we found E- and F-region FAIs appeared frequently: continuous echoes during the post-sunrise period and Quasi-Periodic (QP) echoes at nighttime for E region ; strong post-sunset and pre-sunrise FAIs for F region. The characteristics of E- and F-region FAIs are presented in terms of seasonal and local time variations of occurrence during December 2009 to August 2012. In addition, to investigate the correlation with geomagnetic activity to FAIs occurrence, we compared K-index variations to local time occurrence. It is worth to note our occurrence result since long term observation over several years in the mid-latitude has not yet been carried out.

제한된 자원하에서의 프로젝트 스케쥴링을 위한 발견적 해법

양태용,송주석 한국경영과학회 1987 한국경영과학회 학술대회논문집 Vol.1987-1 No.-

대학의 Entrepreneurship(기업가정신)교육 현황과 특징에 관한 연구

양태용,김인수 대한산업공학회 2006 대한산업공학회 춘계학술대회논문집 Vol.2006 No.5

Corporate Transparency and Firm Performance: Evidence from Venture Firms Listed on the Korean Stock Market

양태용,김영환,이정우 한국증권학회 2013 Asia-Pacific Journal of Financial Studies Vol.42 No.4

This study proposes a new corporate transparency index comprising four sub-indices: financial, governance, operational, and social transparency. Using our index, we examine the effects of corporate transparency on firm value and the profitability of 162 Korean venture firms. Results show that corporate transparency is positively associated with firm profitability. Financial transparency is positively related to firm profitability and negatively associated with firm value. Firms with a greater level of governance transparency have a higher firm value and a lower return on assets. Operational transparency is negatively related to firm value. Social transparency is positively associated with firm value and profit.

Statistical Comparison of Gravity Wave Characteristics Obtained from Airglow All-Sky Observation at Mt. Bohyun, Korea and Shigaraki, Japan

양태용,곽영실,김용하 한국우주과학회 2015 Journal of Astronomy and Space Sciences Vol.32 No.4

Previously, all-sky airglow images observed at Shigaraki (34.9° N, 136.1° E), Japan, during 2004 and 2005 were analyzed in relation to those observed at Mt. Bohyun (36.2° N, 128.9° E) for a comparison of their gravity wave characteristics (Kim et al. 2010). By applying the same selection criteria of waves and cloud coverages as in the case of Mt. Bohyun all-sky images, we derived apparent wavelengths, periods, phase velocities, and monthly occurrence rates of gravity waves at Shigaraki in this study. The distributions of wavelengths, periods, and speeds derived for Shigaraki were found to be roughly similar to those for Mt. Bohyun. However, the overall occurrence rates of gravity waves at Shigaraki were 36% and 34% for OI 557.7 nm and OH Meinel band airglow layers, respectively, which were significantly higher than those at Mt. Bohyun. The monthly occurrence rates did not show minima near equinox months, unlike those for Mt. Bohyun. Furthermore, the seasonal preferential directions that were clearly apparent for Mt. Bohyun were not seen in the wave propagation trends for Shigaraki. These differences between the two sites imply different origins of the gravity waves near the Korean peninsula and the Japanese islands. The gravity waves over the Japanese islands may originate from sources at various altitudes; therefore, wind filtering may not be effective in causing any seasonal preferential directions in the waves in the airglow layers. Our analysis of the Shigaraki data supports recent theoretical studies, according to which gravity waves can be generated from in situ sources, such as mesosphere wind shear or secondary wave formation, in the mesosphere.

알레르기 비염환자에서 레이저 하비갑개성형술과 Coblation 하비갑개성형술의 수술 효과 비교

양태용,황인국,정윤건,장태영 대한비과학회 2009 Journal of rhinology Vol.16 No.2

Background and Objectives:There are many operative methods for allergic rhinitis such as partial or total turbinectomy, submucosal resection. Laser- assisted conchotomy (LACON) and coblation-assisted partial turbinoplasty (CAPT) are recently being commonly performed for minimal invasive surgery. The aim of this study is to compare the subjective and objective results in the groups of patients with allergic rhinitis who underwent LACON or CAPT after long term follow up. Materials and Methods: From January 2006 to January 2007, 64 patients with allergic rhinitis refractory to medical therapy who underwent LACON or CAPT were enrolled in this study. 28 patients had LACON therapy and 36 patients underwent CAPT randomly. The symptom of allergy, duration of crust formation, and nasal patency in acoustic rhinometry were analyzed in months 3, 6, 9, 12 after surgery. Results:With the Visual Analogue Scale (VAS), the patients who received LACON all reported significant differences in allergic symptoms. However, patients who received CAPT reported significant differences only in nasal obstruction and rhinorrhea. There were no significant differences in both groups in regard to nasal patency change (nasal volume, ㎤) and duration of crust formation. Conclusion:As LACON is effective on all symptoms and CAPT is effective only on nasal obstruction and rhinorrhea, the procedures can be performed respectively, depending on the symptoms of patients. Background and Objectives:There are many operative methods for allergic rhinitis such as partial or total turbinectomy, submucosal resection. Laser- assisted conchotomy (LACON) and coblation-assisted partial turbinoplasty (CAPT) are recently being commonly performed for minimal invasive surgery. The aim of this study is to compare the subjective and objective results in the groups of patients with allergic rhinitis who underwent LACON or CAPT after long term follow up. Materials and Methods: From January 2006 to January 2007, 64 patients with allergic rhinitis refractory to medical therapy who underwent LACON or CAPT were enrolled in this study. 28 patients had LACON therapy and 36 patients underwent CAPT randomly. The symptom of allergy, duration of crust formation, and nasal patency in acoustic rhinometry were analyzed in months 3, 6, 9, 12 after surgery. Results:With the Visual Analogue Scale (VAS), the patients who received LACON all reported significant differences in allergic symptoms. However, patients who received CAPT reported significant differences only in nasal obstruction and rhinorrhea. There were no significant differences in both groups in regard to nasal patency change (nasal volume, ㎤) and duration of crust formation. Conclusion:As LACON is effective on all symptoms and CAPT is effective only on nasal obstruction and rhinorrhea, the procedures can be performed respectively, depending on the symptoms of patients.

보현산과 일본 전천 카메라 화상에 나타난 대기 파동의 통계적 특성

양태용,김정한,정종균,원영인,이방용,김용하 한국우주과학회 2006 한국우주과학회보 Vol.15 No.2

중위도 고층대기/전리층 불균일 현상 연구를 위한 VHF 간섭 산란 레이더 설치 및 초기 관측 결과 소개

양태용,곽영실,황정아,이재진,최성환,최호성,조경석,박영득,김연한 한국우주과학회 2010 한국우주과학회보 Vol.19 No.1

한국천문연구원은 우주환경예보센터(Korean Space Weather Prediction Center) 구축사업의 일환으로 고층대기/전리층의 불균일 현상을 관측할 수 있는 VHF 간섭 산란 레이더를 대한민국 공군과 협의를 통해 충남 계룡 (36.18ºN, 127.14ºE)에 설치하였다. 이 레이더는 2007년 ‘우주환경예보를 위한 중·저위도 고층대기 관측시스템 설계를 위한 기초연구’를 통해 선정되어 2009년 설치가 완료되었으며 12월 말부터 정상 관측을 수행하고 있다. 5 소자의 총 24기의 안테나가 12x2의 배열을 이루어 최대 출력 24kW, 단일 주파수 40.8MHz로 전리층 E층과 F층을 관측하여 중위도 고층대기의 불균일 현상을 관측하고 있다. 앞으로 천문연구원의 전천카메라, 자력계, 신틸레이션 모니터와 더불어 중위도 지역의 고층대기와 우주환경예보에 대해 지속적인 관찰 및 연구가 가능하다. 이 발표에서는 우리나라의 첫 고층대기/전리층 관측 VHF 레이더의 설치 과정과 현재까지 계룡 관측소에서 관측한 중위도 전리층의 레이더 초기 관측 자료를 소개하고자 한다.