최소 통계법과 Short-Term 예측계수 코드북을 이용한 Non-Stationary/Mixed 배경잡음 추정 기법

이명석,노명훈,박성주,이석필,김무영,Lee, Myeong-Seok,Noh, Myung-Hoon,Park, Sung-Joo,Lee, Seok-Pil,Kim, Moo-Young 한국음향학회 2010 韓國音響學會誌 Vol.29 No.3

본 논문에서는 배경잡음에 강인한 잡음제거 알고리즘 설계를 위해서 minimum statistics (MS) 기법을 codebook driven short-term predictor parameter estimation (CDSTP) 기법에 접목하는 방법을 제안한다. MS는 stationary 배경잡음에는 강인하지만, non-stationary 배경잡음에는 상대적으로 취약하다. CDSTP는 non-stationary 배경잡음에 강인한 특성을 보이지만, 코드북에 없는 배경잡음 환경에는 취약하다. 따라서 non-stationary 배경잡음에 강인한 CDSTP 방법과 별도의 코드북 학습 과정이 필요 없는 MS를 결합해서 다양한 배경잡음에 강인한 알고리즘을 제안한다. 제안방법은 MS나 CDSTP 방법에 비해서 전체적으로 향상된 perceptual evaluation of speech quality (PESQ) 성능을 나타냈으며, 특히 stationary 배경잡음과 non-stationary 배경잡음이 섞여 있는 mixed 배경잡음 환경에서 강인한 특성을 보였다. In this work, the minimum statistics (MS) algorithm is combined with the codebook driven short-term predictor parameter estimation (CDSTP) to design a speech enhancement algorithm that is robust against various background noise environments. The MS algorithm functions well for the stationary noise but relatively not for the non-stationary noise. The CDSTP works efficiently for the non-stationary noise, but not for the noise that was not considered in the training stage. Thus, we propose to combine CDSTP and MS. Compared with the single use of MS and CDSTP, the proposed method produces better perceptual evaluation of speech quality (PESQ) score, and especially works excellent for the mixed background noise between stationary and non-stationary noises.

Cross-flow filtration에 의한 Bifidobacterium longum의 고농도 배양

이명석,박연희,Lee, Myong-Suk,Park, Yun-Hee 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.43 No.1

Bifidobacterium longum을 고농도 배양하기 위하여 최적 생육 조건을 조사하고 cross-flow filtration으로 생육 저해 대사산물인 lactic acid와 acetic acid를 제거하면서 균체 순환 배양을 사용하였다. 회분 배양에서는 탄소원으로 glucose를 50 g/l 농도로 사용하고 초기 pH 6.5인 경우 생육이 가장 높았다. B. longum을 cross-flow filtration으로 12시간 배양한 결과, 희석속도 $0.31h^{-1}$에서 최대 균체농도에 도달하여 16.4g/l의 건조균체량을 얻었으며 이로써 회분 배양시 보다 약 4배 높은 균체를 생산하였다. The conditions for production of high cell density of Bifidobacterium longum were investigated and the cross-flow filtration system was used to remove the inhibitory metabolites, lactic acid and acetic acid. The maximum cell growth was observed with glucose as carbon source at the concentration of 50 g/l at $37^{\circ}C$ with the initial pH 6.5. When B. longum was cultured in a cross-flow filtration system, the maximum cell growth was observed at a dilution rate(D) of $0.31\;h^{-1}$ and the dry cell weight was 16.4 g/l($3.5{\times}10^{10}\;cell/ml$), which was about four times higher than that obtained in the batch culture with pH control.

연출이 대면하는 텍스트, 그 텍스트성

이명석,Lee, Myeong-Seok 대한출판문화협회 2007 출판저널 Vol.375 No.-

다목적 헬기용 DIRCM의 시뮬레이션 기반 장착위치 선정 연구

이명석,신백천,허장욱,김미정,Lee, Myeong Seok,Shin, Baek Cheon,Hur, Jang Wook,Kim, Mi Jeong 한국시스템엔지니어링학회 2019 시스템엔지니어링학술지 Vol.15 No.1

DIRCM is a device that deception missiles by directing the light source to missile seeker with infra-red laser based turret. The effectiveness of the device is affected by changes of the turret's Field of View (FoV), and also influence of the interference devices determines the effect of the DIRCM's effectiveness. Therefore finding mounting location for DIRCM is critical parameter for the DIRCM's effectiveness. so we applied stiffness review, interference analysis, FoV analysis and simulation analysis method to Multi-purpose helicopter for the find DIRCM location. As a result, in case of 1 DIRCM mounted at helicopters bottom shows 30~40% survivability. case of 2 DIRCM mounted at both side shows 70~80% survivability.

전동기 시스템의 미지외란 및 전류 관측기 설계

이명석,정경모,공경철,Lee, Myoungseok,Jung, Kyungmo,Kong, Kyoungchul 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.7

DOB (Disturbance Observer) is an useful control method for estimating the disturbance applied to dynamic systems. Disturbance observer can be used to implement a robust control system to generate a control input for rejecting the disturbance, and it can be also used to estimate the disturbance to obtain information. The system that uses disturbance estimation is investigated for high performance control such as automatic door systems, walking robot and electric power steering system in vehicles. In this paper, a novel disturbance observer which is called disturbance and current observer for estimating load torque in the motor system is proposed. The difference between the DOB for disturbance rejection and DCOB is mathematically verified. Current and angular velocity are required for estimating the load torque of the motor in DOB. However, the DCOB can estimate load torque and current without current sensor. DCOB is designed based on modeling of the motor system. Appropriate Q-filter is selected and the applicability of DCOB is verified by simulation. The estimated disturbance and current of the electric motor can be verified without current sensor, as experiments of the actual motor system.

가변 전압기와 역기전력 차동방식을 이용한 센서리스 BLDC 전동기 드라이버 설계

이명석,공경철,Lee, Myoungseok,Kong, Kyoungchul 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.10

A sensorless motor control scheme with conventional back-Electro Motive Force (EMF) sensing based on zero crossing point (ZCP) detection has been widely used in various applications. However, there are several problems with the conventional method for effectively driving sensorless brushless motors. For example, a phase mismatch of 30 degrees occurs between the ZCP and commutation time. Additionally, most of the motor speed/current controls are achieved based on a pulse width modulation (PWM) method, which generates significant noise that distracts the back-EMF sensing. Due to the PWM switching, the ZCP is not deterministic, and thus the efficiency of the motor is reduced because the phase transition points become uncertain. Moreover, the motor driving performance is degraded at a low speed range due to the effect of PWM noise. To solve these problems, an improved back-EMF detection method based on a differential line method is proposed in this paper. In addition, the proposed sensorless BLDC driver addresses the problems by using a variable voltage driver generated from a buck converter. The variable voltage driver does not generate the PWM switching noise. Consequently, the proposed sensorless motor driver improves 1) the signal-to-noise ratio of back-EMF, 2) the operation range of a BLDC motor, and 3) the torque characteristics. The proposed sensorless motor driver is verified through simulations and experiments.

여드름균(Cutibacterium acnes)에 대한 해조류 추출물의 항균효과

이명석 ( Myeong Seok Lee ),임미진 ( Mi-jin Yim ),이정민 ( Jeong Min Lee ),이대성 ( Dae-sung Lee ),김영목 ( Mog-young Kim ),엄성환 ( Sung-hwan Eom ) 한국수산과학회(구 한국수산학회) 2021 한국수산과학회지 Vol.54 No.1

The study was aimed at developing an alternative therapeutic agent against acne vulgaris, one of the most common skin diseases, to meet the continuing demand for new therapies. Acne vulgaris is often associated with the acne-causing bacteria such as Cutibacterium acnes. To investigate the safety of agents against acne vulgaris, we evaluated the potential antibacterial activities of edible seaweeds against C. acnes in Korea. Forty-one edible seaweeds, including the brown, green, and red varieties, were selected for the antibacterial test. In comparison with other seaweeds, 70% ethanolic extracts of brown seaweeds, such as Cladophora wrightiana var. minor, Eisenia bicyclis, Ecklonia cava, Ishige foliacea, Ishige okamurae, Sargassum filicinum, and Sargassum miyabei Yendo, exhibited potential antibacterial activity against C. acnes with minimum inhibitory concentrations ranging between 64 and 128 μg/mL. To investigate the active anti-acne agents and to enhance our understanding of the antibacterial activities against C. acnes, further solvent-fractionation experiments are warranted. The findings imply that brown seaweeds can be a potential source of natural agents against acne vulgaris.

생태학적 신학의 발전에 대한 탐구와 선교적 적용

이명석 ( Lee Myeong Seok ) 한국복음주의선교신학회 2020 복음과 선교 Vol.50 No.-

20세기 후반 전 세계적으로 환경문제가 대두되고 생태위기가 고조되면서 새로운 신학적인 주제로서 생태학적인 관점으로 창조세계 전반을 포괄하고자 하는 전환이 서서히 일어나기 시작했다. 생태신학(ecotheology)은 이러한 환경생태 문제와 사회경제적인 변화의 현실 속에서 하나님께서 창조하신 세상을 새롭게 해석하고자 하는 해석학적 틀로서 등장하였다. 생태신학은 생태와 종교와의 관계와 인간사회가 자연과의 관계 속에서 변화되는 것을 연구하는 신학이다. 다르게 표현하면 생태신학은 하나님과 인간 그리고 우주와의 관계에 대해 적정한 신학적인 기초를 놓는 데 그 목적이 있다. 이 글은 세계적으로 생태계 전체의 생존을 위협하는 환경문제와 생태위기 속에서 생태신학이 태동하게 된 역사적 배경과 그 전개 과정을 비판적으로 탐구한다. 그리고 그러한 생태신학을 한국교회가 선교적으로 적용할 방법을 모색하는 데 그 목적이 있다. 이 글에서 필자는 먼저 서구 사회에서 생태신학이 태동하게 된 배경과 과정 그리고 신학적 한계에 대해서 비판적으로 조사하고자 한다. 또한 한국의 독특한 정치와 경제 상황에서 신학적으로 생명에 대한 관심이 발전하게 된 과정을 살펴보고 이를 통해 한국교회가 지향하고자 하는 생명선교의 선교적인 의미를 알아본다. 아울러 현재의 전 지구적인 환경생태 위기에서 남방교회들이 선교적으로 협력할 수 있는 방안에 대해서 살펴본다. 이러한 조사를 바탕으로 한국 교회의 생태신학적 선교의 적용이 세계교회에 어떻게 공헌할 수 있는지에 대해서 제안하고자 한다. By the end of the 20th century, increased in the global environmental and ecological crises brought about social and economic changes worldwide. This attracted a number of theological responses and debate. An ecotheology, contextual in character and expression, emerged to create an awareness on the environmental/ecological challenges and preserve God’s creation. Taking the contemporary context as its starting point, theologians raise a wide range of cultural and theological concerns as they studied the relationship between ecology and religion and seek transformation in the way human societies function in relation to the rest of the natural world. Their main concern was to establish the theological basis for a proper relationship between God, humanity and the cosmos. This paper explores the development of ecotheological thought from historical and cultural contexts, in the ecological and climatic conditions of the time and further suggests its implications in Christian missions. For this purpose, the paper examines the western ecotheological approaches to the environmental/ecological crises and also evaluate the development of ecotheological thought in Korea, by highlighting the life-giving components. With this insight, the researcher suggests some implications for Christian missions that engage 21st century Korean Christians to be better equipped in missional task towards a more sustainable and harmonious living relationship between humans and all life forms in nature.

협력적 거버넌스와 정부의 역할 -사회적 기업 사례를 중심으로

이명석 ( Myung Suk Lee ),배재현 ( Jae Hyun Bae ),양세진 ( Se Jin Yang ) 한국정책학회 2009 韓國政策學會報 Vol.18 No.4

공격헬기 개발을 위한 무장 비행시험 탄약발수 최적화 연구

이명석(Myeong-Seok Lee),허장욱(Jang-Wook Hur) 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.8

헬기와 같은 항공기의 신규 개발에는 시제품 설계 및 제작과 함께 많은 시간동안 비행시험을 통한 안전성 검증이 요구된다. 비행시험을 수행하는 시험평가 단계는 시스템의 개발에 있어 성공을 좌우하는 중요한 과정이며, 특히, 공격헬기 개발을 위해서는 무장분야 비행시험을 통한 안전성 검증이 매우 중요하다. 이러한 공격헬기의 개발에 있어서 무장분야 비행시험 관련 시험평가 기간 및 비용은 비행시험의 소요탄약 발수와 밀접한 관계가 있다. 따라서, 본 논문에서는 미 군사 규격인 ADS-44-HDBK와 유사 사례로 AH-1 헬기의 분석을 통해 공격헬기 개발 간 무장분야 비행시험에 요구되는 탄약소요량을 제시하였다. AH-1 헬기의 사례 분석을 통해 중복 사격시험 배제 및 형상차이를 고려하여 탄약 요구량 산출이 가능하며, 기관총 장착 형상의 경우 사격시험 관련 탄약이 약 10,500R 요구되고, 로켓 장착 형상의 경우 사격시험 관련 탄약이 약 324R 요구된다. 또한, 무장통합벤치를 적절하게 사용을 한다면 무장분야 비행시험간 발생 가능한 위험요소 식별하여 미연에 배제함으로써 무장분야 비행시험의 효율적 추진이 예상된다. Developments in aircraft require safety verification through flight testing for many hours with prototype design and production. The test evaluation step of performing flight tests was an important process that determines the success in the development of the system. In particular, safety development through flight tests in the armed flight test is important for the development of attack helicopters. In the development of attack helicopters, the evaluation period and cost related to the armed flight test are closely related to the required ammunition requirement. Therefore, this paper presents the amount of ammunition required for the military flight test between attack helicopter developments through an analysis of the AH-1 helicopter in a similar case and ADS-44-HDBK of military specification. The AH-1 can be used to calculate the ammunition demand by considering the exclusion of redundant firing tests and configuration differences. In the case of the machine gun-equipped configuration, approximately 10,500R was required, and approximately 324R was required in the case of a rocket-mounted configuration. In addition, if the armed integrated bench is used properly, it is expected to promote efficiently the flight test in the armed flight by identifying the possible risk factors with armed flight tests and excluding them.