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A Singular Perturbation-Like Approach to EDFA Gain Control Based on Observer Techniques
Seong-Ho Song,Dong Eui Chang,Kwang Y. Lee,Ho-Chan Kim 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4
In this paper, we propose a singular perturbation-like approach to EDFA gain controller design and analysis. Considering a three-level model of EDFA, a gain controller containing a state observer and a channel add/drop estimator is designed based on a singular perturbation - like concept. The proposed design methodology is shown to be effective and advantageous not only in theoretically verifying the asymptotic stability of systems with multi-time scales such as EDFA but also in designing an asymptotic estimator for channel add/drops which does not satisfy the matching condition.
Effects of the Misspecification of Cointegrating Ranks in Seasonal Models
Seong, Byeong-Chan,Cho, Sin-Sup,Ahn, Sung-K.,Hwang, S.Y. The Korean Statistical Society 2008 응용통계연구 Vol.21 No.5
We investigate the effects of the misspecification of cointegrating(CI) ranks at other frequencies on the inference of seasonal models at the frequency of interest; our study includes tests for CI ranks and estimation of CI vectors. Earlier studies focused mostly on a single frequency corresponding to one seasonal root at a time, ignoring possible cointegration at the remaining frequencies. We investigate the effects of the mis-specification, especially in finite samples, by adopting Gaussian reduced rank(GRR) estimation by Ahn and Reinsel (1994) that considers cointegration at all frequencies of seasonal unit roots simultaneously. It is observed that the identification of the seasonal CI rank at the frequency of interest is sensitive to the mis-prespecification of the CI ranks at other frequencies, mainly when the CI ranks at the remaining frequencies are underspecified.
A Singular Perturbation-Like Approach to EDFA Gain Control Based on Observer Techniques
Song, Seong-Ho,Chang, Dong Eui,Lee, Kwang Y.,Kim, Ho-Chan The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4
In this paper, we propose a singular perturbation-like approach to EDFA gain controller design and analysis. Considering a three-level model of EDFA, a gain controller containing a state observer and a channel add/drop estimator is designed based on a singular perturbation - like concept. The proposed design methodology is shown to be effective and advantageous not only in theoretically verifying the asymptotic stability of systems with multi-time scales such as EDFA but also in designing an asymptotic estimator for channel add/drops which does not satisfy the matching condition.
Lee, Jae-Keun,Kim, Seong-Chan,Benjamin Y.H. Liu The Korean Society for Energy 1996 에너지공학 Vol.5 No.2
Typical size distribution of emission particulates is bi-modal in shape with particles in the fine mode (< 2.0 $\mu\textrm{m}$) and the coarse mode. An experimental study of pressure drop across the industrial gas cleaning filters has been conducted using particle mixture of fine alumina and coarse Arizona dusts with a rotating aerosol disperser to generate the bi-modal test aerosol. Pressure drop increased linearly with increasing mass loading. The pressure drop was found to be strongly dependent upon the mass ratio of fine to coarse particles. The smaller the mass ratio of fine to coarse particles and the higher face velocity are, the faster pressure drop rises. The fine particles and the greater inertia of the particle moving fast would cause a denser cake formation on the filter surface, resulting in a greater specific resistance to the gas flow.
Kang, Ye S.,Ryu, Chan S.,Jun, Sae R.,Jang, Si H.,Park, Jun W.,Song, Hye Y.,Sarkar, Tapash K.,Kim, Seong H.,Lee, Won S. Elsevier 2018 BIOSYSTEMS ENGINEERING Vol.176 No.-
<P>Classification of crop species is an actively studied topic in remote sensing using multispectral image sensors. Unfortunately, the spectral bands available in the multispectral imagery are broad and limited in number to classify the crop species. In this paper, we propose optimal spectral bands to classify Allium (garlic and onion) and Brassicaceae (Chinese cabbage and radish) by using higher-dimensional data from hyperspectral imagery. A decision-tree classifier was used to determine the optimal method to use the high-dimensional data. The high-dimensional data were analysed for all growth stages and considering bandwidths with different full width at half maximum (FWHM) values at 25, 40, 50 and 80 nm. The spectral bands selected for Allium were differentiated into green, blue, and NIR bands for each growth stage. The results show that Allium can be classified clearly as overall accuracy (OA) 1 and kappa coefficient 1 for all FWHM based on March 22 data. For each April 19 and May 12 data, the decision-tree classifier with each 80 nm FWHM and 50 nm FWHM yielded a better classification accuracy of more than OA 0.921 and kappa coefficient 0.839 than other FWHM. The spectral bands selected for Brassicaceae were found to be similar to blue band for all growth stages. Brassicaceae was classified clearly for all FWHM based on October 27 data. Also, Brassicaceae was classified clearly for 25 nm FWHM based on November 25 data and OA, kappa coefficient for 40 nm FWHM and 50 nm FWHM are high as 0.974, 0.947 respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We propose commercial band pass filters to identify Allium and Brassicaceae. </LI> <LI> Decision-tree classifier based on hyperspectral data selects the spectral filters. </LI> <LI> Hyperspectral data analysed depending on growth stages and different filter bandwidth. </LI> <LI> Allium is efficiently classified in Green, Blue and NIR bands for each growth stage. </LI> <LI> Brassicaceae is classified in Blue bands throughout all growth stages. </LI> </UL> </P>
정인범 ( In Beom Jeong ),이태희 ( Tae Hee Lee ),임성민 ( Seong Min Lim ),류기현 ( Ki Hyun Ryu ),김용석 ( Yong Seok Kim ),김선문 ( Sun Moon Kim ),임의혁 ( Euyi Hyeog Im ),허규찬 ( Kyu Chan Huh ),최용우 ( Young Woo Choi ),강영우 ( Y 대한소화기학회 2011 대한소화기학회지 Vol.58 No.6
Background/Aims: The endoscopic findings and clinical relevance of portal hypertensive colopathy are not well described in Korea. We aimed to do a retrospective study of mucosal changes in the colon of patients with liver cirrhosis and to find their association with clinical characteristics. Methods: We reviewed the clinical data and endoscopic findings of 48 patients with liver cirrhosis and 48 patients, matched for age and sex, with irritable bowel disease (IBS) who underwent colonoscopy over a 5 year span. Results: Patients with liver cirrhosis were more likely to have colitis-like lesions and vascular abnormalities than IBS patients. Low platelet count (p=0.005) and severe esophageal varices (p=0.011) were associated with portal hypertensive colopathy, whereas the etiologies and severity of cirrhosis were not associated with these findings. Conclusions: Portal hypertensive colopathy can be defined with colitis-like lesions or vascular lesions. These lesions are more frequently present in patients with more severe esophageal varices and thrombocytopenia. (Korean J Gastroenterol 2011;58:332-337)
보건직 여성공무원의 인유두종바이러스 감염에 대한 인식 및 지식조사
조동휴 ( Dong Hyu Cho ),김은경 ( Eun Kyung Kim ),이동현 ( Dong Hyun Lee ),최원구 ( Won Ku Choi ),임은지 ( Eun Ji Lim ),김종현 ( Jong Hyun Kim ),이정헌 ( Jeong Heon Lee ),조성남 ( Seong Nam Cho ),오병찬 ( Byung Chan Oh ),정영주 ( Y 대한산부인과학회 2010 Obstetrics & Gynecology Science Vol.53 No.5
목적: 보건직 여성공무원의 인유두종바이러스 감염에 대한 인식도와 지식도를 알아보기 위해 본 연구를 실시하였다. 연구 방법: 2007년 4월부터 6월까지 전라북도 보건직에 종사하는 공무원 여성 총 991명에게 인터넷을 통한 설문을 실시하였다. 사용된 설문은 일차적으로 대상자의 일반적 특성을 묻는 11문항, human papillomavirus (HPV) 감염에 대한 지식을 묻는 9문항으로 구성되었다. 결과: 완전하게 설문답변을 한 546명 중 인유두종바이러스에 대해 들어 본 적이 있다고 답한 여성은 145명 (37.6%)이었다. 인유두종바이러스 감염과 관련된 인식도는 기혼여성, 성경험이 있었던 여성, 과거 자궁경부암 검사상 이상이 있었던 경우, 성병기왕력이 있었던 경우, 정기적으로 1년에 한 번씩 자궁경부암 검진을 받고 있는 경우에 유의하게 높았다. HPV 감염에 대해 들어 본 적이 있다고 답한 여성에 있어서, HPV 감염에 대한 지식을 묻는 문항 정답률의 총 평균은 56.3%였다. 70% 이상 높은 정답률을 보인 질문은 4문항이었다. `HPV는 자궁경부암을 일으키는 주된 원인이다` 124명 (88.6%), `HPV는 성교를 통해 감염되는 질환이다` 111명 (79.3%), `피임약을 통해 HPV 감염을 예방할 수 없다` 107명 (76.4%), `남자가 HPV를 옮길수 있다` 100명 (71.4%). 정답률이 50% 미만은 3문항이었다. `HPV는 크게 고위험군과 저위험군 2가지로 나뉘어져 있다` 62명(44.3%), `HPV 감염은 평생 지속된다` 41명 (29.3%), `콘돔으로 HPV 감염을 예방할 수 있다` 18명 (12.9%). 결론: 보건직 여성공무원의 HPV 감염에 대한 인식도와 지식도는 낮은 편이었다. 따라서 여성들의 HPV 감염에 대한 인식 및지식 정도를 높이기 위해서는 매스미디어를 통한 더 많은 교육과 홍보가 필요하다. Objective: To assess the level and accuracy of understanding of human papillomavirus (HPV) infection among female public health personnel in Chonbuk province. Methods: Nine hundred ninety-one female public health personnel were asked to complete a questionnaire assessing HPV awareness and specific knowledge about the virus. The questionnaire contained 11 demographic informations and nine true-false questions on knowledge about HPV infection. Results: Questionnaires were completed by 546 women, of whom 145 (37.6%) had heard of HPV. Married women (P=0.019), those with a history of candida, genital warts (P<0.001), or an abnormal smear result (P=0.001), annually visitor for a Pap smear (P=0.023) were more likely to have heard of human papilloma virus. Medical doctor (38.6%) was the most common source of hearing of HPV. Overall percentage of knowledge among those who had heard of HPV was 56.3%. Responses indicated than more than 70% had up-to-date knowledge about several issues: HPV is the main cause of cervical cancer, HPV is sexually transmitted, The pill protects against HPV, and Men can carry HPV. Fewer than 50% knowledge of HPV infection were as follows: HPV viruses are divided to low-risk and high-risk type, HPV infections persist forever, condoms protect against HPV. Conclusion: In this well educated samples, awareness of HPV infection was poor. And also, knowledge about HPV infection was relatively low. We recommend that more educational effort is needed for improving women`s knowledge and awareness of HPV infection.