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불규칙 잡음 신호가 첨가된 정현파의 주파수 추정에 관한 연구
강철호 光云大學校 1991 論文集 Vol.20 No.-
It is a very important theme in the signal processing areas to estimate the frequency of sinusoid in adaptive random noise. In this study interactive frequency estimator was suggested to get over the constraints of adaptive line enhancer by interactive filtering technique based on Burg algorithm useful for AR parameter estimation. The adaptive line enhancer, which is used to detect the extremely low-level sine waves in random noise, is combined with interactive frequency estimator to resolve the closed space sinusoids at low SNR(signal-to-noise ratio). In this case sinusoidal waves in random noise are detected and applied to the all-pole filter. Simulation results show that the performance of conventional frequency estimator has been improved in terms of background noise by means of adaptive filtering.
강철호 光云大學校 1985 論文集 Vol.14 No.-
A new method is proposed to reduce the image data by mixing two different images in image communication. This method is applied to the existing image coding system for data compression without any change. The magnitude and the phase of each image are computed by discrete Fourier transform(DFT) to combine the magnitude component of one image and the phase component of the other image. At the receiver the algorithms for signal reconstruction from phase or magnitude are used to recover original two images from one mixed image. In this paper the proposed method is proved to be reasonable through computer simulation of this procedure with two standard images.
보강 섬유의 배향각에 대한 확률밀도함수를 고려한 ECC내의 섬유 가교 모델
강철호,이방연,박승범,김윤용,Kang, Cheol-Ho,Lee, Bang-Yeun,Park, Seung-Bum,Kim, Yun-Yong 한국전산구조공학회 2009 한국전산구조공학회논문집 Vol.22 No.6
The fiber bridging model is the crucial factor to predict or analyze the tensile behavior of fiber reinforced cementitious composites. This paper presents the fiber bridging constitutive law considering the distribution of fiber inclined angle and the number of fibers in engineered cementitious composites. The distribution of fiber inclined angle and the number of fibers are measured and analyzed by the image processing technique. The fiber distribution are considerably different from those obtained by assuming two- or three-dimensional random distributions for the fiber inclined angle. The simulation of the uniaxial tension behavior was performed considering the distribution of fiber inclined angle and number of fibers measured by the sectional image analysis. The simulation results exhibit multiple cracking and strain hardening behavior that correspond well with test results. 섬유 가교 곡선은 섬유보강 시멘트 복합체의 인장 거동을 예측하고 분석하는데 중요한 요인이다. 이 연구의 목적은 ECC에서 섬유 배향각의 분포와 섬유 개수를 정량적으로 고려할 수 있는 섬유 가교 모델을 제시하는 것이다. 이를 위하여 먼저 섬유 배향각과 섬유 개수를 정량적으로 고려할 수 있는 섬유 가교 모델을 유도하였다. 섬유 배향각과 섬유 개수는 이미지 프로세싱 기법을 사용하여 계측하였다. 이미지 분석을 통하여 계측한 섬유 배향각에 대한 확률밀도함수와 섬유 개수는 섬유 배향각을 2차원이나 3차원에 무작위로 분포된 것으로 가정하는 것과 큰 차이를 보였다. 이는 타설방법이나 유동흐름에 따라 섬유 분포 특성이 영향을 받기 때문으로, 모델의 검증을 위해 정확한 섬유분포 특성을 파악할 필요가 있다. 따라서 이미지 프로세싱 방법으로 계측한 섬유 분포 특성을 근간으로 보강섬유의 배향각과 단면 내 섬유 개수를 고려하여 얻은 섬유 가교 곡선으로 1축 인장 거동을 모사하였다. 모사한 1축 인장 거동은 실험 결과와 유사하게 다중 균열과 변형률 경화 거동을 보이는 등 1축 인장 거동을 정확히 나타낼 수 있는 것으로 검증되었다.
오수과(吳茱菓)가 PTU로 유발된 갑상선기능저하증 Rat의 갑상선기능 및 조직학적 변화에 미치는 영향
강철호,송문구,강지석,이병철,안영민,두호경,안세영,Kang, Chul-Ho,Song, Moon-Koo,Kang, Ji-Suck,Lee, Byung-Cheol,Ahn, Young-Min,Doo, Ho-Kyung,Ahn, Se-Young 대한한방내과학회 2008 大韓韓方內科學會誌 Vol.29 No.4
Objective : Hypothyroidism is a syndrome characterized by symptoms such as cold intolerance, or weight gain. Because of side effects of Western medicine treatment, interest in oriental medicine has been increasing. In this study, we examined the therapeutic effects of Evodiae fructus and histological modification in hypothyroidism rat model induced by PTU(6-propyl, 2-thiouracil). Methods : After inducing hypothyroidism in the rats by PTU injections, we divided the rats into four groups, the Evodiae fructus 100 500, control, and $LT_4$ (levothyroxine) groups. After 2 weeks Evodiae fructus and $LT_4$ were administered, respectively. The weight was measured once a week. After sampling the blood for biochemical analysis to check the levels of $T_3$, $T_4$ and TSH, the thyroid tissue was removed, stained with H&E, and an image was obtained using an optical microscope. Results : Compared with normals, controls showed low $T_4$ and high TSH. The Evodiae fructus group showed a statistically meaningful $T_3$ increase to be dose related. But the levels of TSH showed no meaningful difference between the Evodiae fructus group and normals. About the biochemical tests(liver, kidney etc) and weight change, there was no meaningful difference between the Evodiae fructus group and controls. In the biopsy, the Evodiae fructus group showed thyroid tissue improvement compared to controls. Conclusions : These results show that Evodiae fructus stimulates the decreased functions of the thyroid, and also has thyroid cell protecting effects. The lab results also showed that Evodiae fructus is a safe substance that doesn't cause hepatotoxicity or nephrotoxicity. Therefore it is an effective substance in the treatment of hypothyroidism.