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능동소나 linear frequency modulation 신호의 fractional Fourier transform 분석에 기반한 표적의 거리 추정
형성웅,박명호,황수복,배건성,Hyung, Sungwoong,Park, Myungho,Hwang, Soobok,Bae, Keunsung 한국음향학회 2016 韓國音響學會誌 Vol.35 No.1
Fractional 푸리에 변환(Fractional Fourier Transform : FrFT)은 기존의 푸리에 변환의 일반화된 형태로서, 변환차수 ${\alpha}$에 따라 임의의 시간-주파수 영역에서의 신호해석이 가능하다. FrFT는 특히 LFM(Linear Frequency Modulation) 신호의 분석에 있어 잡음에 강한 특성으로 인해 많은 장점을 가진다. 본 논문에서는 능동소나에서 표적에 맞고 반향된 수신신호의 FrFT 스펙트럼으로부터 표적과의 거리를 추정하는 새로운 방법을 제안하였다. 합성한 표적 신호를 통해 제안한 방법의 타당성을 검증하였으며, 실제 수중 실험을 통해 얻은 잡음 및 잔향 환경에서의 신호에서도 신뢰성 있는 표적과의 거리 추정이 가능함을 확인하였다. As a generalized form of the conventional Fourier transform, fractional Fourier transform (FrFT) can analyze a signal at intermediate domain between time and frequency domains with a transform order ${\alpha}$. Especially, FrFT has a number of advantages in the analysis of LFM (Linear Frequency Modulation) signals due to its robustness to noise. In this paper, we have proposed a new method to detect and estimate the distance of the target from the FrFT spectrum of the received echo signal. Experimental results have validated the proposed method, and shown that reliable target distance could be estimated in noise and reverberation environments.
주성웅 ( Seong Woong Joo ),신종대 ( Jong Dae Shin ),신동경 ( Dong Kyung Shin ),홍성훈 ( Seong Hun Hong ),기준성 ( Jun Sung Ki ),황진일 ( Jin Ii Hwang ),유병돈 ( Byung Don You ) 대한금속재료학회(구 대한금속학회) 2012 대한금속·재료학회지 Vol.50 No.10
The reduction behavior of low level oxides such as (T.Fe), (MnO) and (P2O5) in molten EAF slag was investigated using commercial reductants. In an air atmosphere, the slag volume increased and the reduction rate of the slag was very low due to the oxidation loss of reductants by oxygen in the air. The reduction rate of the slag was also low when a commercial reductant was used alone in an Ar gas atmosphere. The reason is probably because the material transfer through the interface between the slag and reductant is difficult due to the formation of high melting point oxide. When reductants were mixed with burnt lime in order to form low melting point reaction products, the reduction rate of the slag increased up to the range of 45-70%. By using the mixtures of reductants and burnt lime so as to form a low melting point slag at the reaction end, the reduction rate of the slag was improved up to 60-85%.
Casein kinase 2 is a critical determinant of the balance of Th17 and Treg cell differentiation
장성웅,황수석,김형수,이경오,김민경,이원용,김기완,이갑열 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-
Th17 cells promote inflammatory reactions, whereas regulatory T (Treg) cells inhibit them. Thus, the Th17/Treg cell balance is critically important in inflammatory diseases. However, the molecular mechanisms underlying this balance are unclear. Here, we demonstrate that casein kinase 2 (CK2) is a critical determinant of the Th17/Treg cell balance. Both the inhibition of CK2 with a specific pharmacological inhibitor, CX-4945, and its small hairpin RNA (shRNA)-mediated knockdown suppressed Th17 cell differentiation but reciprocally induced Treg cell differentiation in vitro. Moreover, CX-4945 ameliorated the symptoms of experimental autoimmune encephalomyelitis and reduced Th17 cell infiltration into the central nervous system. Mechanistically, CX-4945 inhibited the IL-6/STAT3 and Akt/mTOR signaling pathways. Thus, CK2 has a crucial role in regulating the Th17/Treg balance.
박문수,이경희,황성웅 한국농촌경제연구원 2012 농촌경제 Vol.35 No.1
The purpose of this study is to identify the price transmission mechanism in livestock markets in Korea as well as the market, in the marketing hierarchy, that has played important role in price discovery. To this end, this study used a time series analysis based on contemporaneous causal relationship, while taking into account the prices of substitutes as well. It showed that the retail price in beef markets and the wholesale prices in pork markets are most important in price discovery. When a short-term impact occurs, the producer price explains most of forecast error variance in beef and the wholesale price explains most of it in pork. We expect that the result of the study would contribute to understanding price trends and forecasting livestock prices.