두 종류의 스펙트럼영역 빛간섭단층촬영기를 사용한 정상 한국인의 맥락막 두께 측정의 재현성

이광현,이성철,이승규.Kwang Hyun Lee. MD. Sung Chul Lee. MD. Christopher Seungkyu Lee. MD 대한안과학회 2013 대한안과학회지 Vol.54 No.9

Purpose: To investigate the reproducibility of choroidal thickness measurements in healthy Koreans using two spectral domain optical coherence tomography (SD-OCT) instruments: Zeiss Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA, USA) and Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). Methods: Images were obtained in 60 eyes of 30 healthy undilated volunteers without ocular pathology in a clinical setting. The choroid was imaged in all subjects using Cirrus HD 1-line raster and Spectralis enhanced depth imaging (EDI). The choroid was measured subfoveally, 1500 μm temporal, and 1500 μm nasal to the fovea. All measurements were performed by two independent observers. One-way analysis of variance (ANOVA), Pearson correlation, and Bland–Altman analysis were used to compare measurements. Results: The study group consisted of 15 males and 15 females. The mean age was 50.73 ± 15.09 years (range, 24-75 years). There was no significant difference in the mean choroidal thickness (p > 0.05) between systems for any location. The choroidal thickness measurements using two instruments (Cirrus vs. Spectralis) were also strongly correlated (p < 0.001). Conclusions: In the present study of healthy Korean adults, good reproducibility was observed between choroidal thickness measurements of images obtained from Cirrus and Spectralis.

수부에 발생한 지방종성 종양

이광현,이봉근,봉현종,Lee, Kwang-Hyun,Lee, Bong-Gun,Bong, Hyun-Jong 대한근골격종양학회 2008 대한골관절종양학회지 Vol.14 No.2

목적: 지방종성 종양은 수부에서 발생하는 경우는 드문 것으로 알려져 있다. 저자들은 수부에 발생한 지방종성 종양 11예를 수술적으로 치료하였기에 그 임상적 특성을 보고하고자 한다. 대상 및 방법: 1992년부터 2008년까지 수부종양으로 수술받았던 환자 중 조직학적으로 지방종성 종양으로 진단받은 환자를 선별하였으며 후향적으로 그 특성을 조사하였다. 의무기록 및 방사선학적 검사 그리고 수술전후 사진기록을 조사하였다. 재발여부는 전화면담을 통해 확인하였다. 결과: 11예 중 8예가 지방종이었으며 비전형 지방종(atypical lipoma)가 1예, 조갑하 혈관 지방종(subungal angiolipoma)가 1예, 섬유지방종(fibrolipoma)이 1예이었다. 발생부위로 수지에 발생한 경우가 4예이었으며 무지구근부 2예, 소지구근부 2예, 수장부 1예, 손목 2예이었다. 전례에서 수장부에 발생하였다. 증상으로 대부분 종물감을 호소하였으며, 통증이 동반된 경우는 2예, 감각이상을 호소한 경우가 1예 있었다. 통증이 있었던 2예 중 1예는 조갑하 혈관지방종이었고 1예는 수장부에 발생한 단순 지방종이었다. 비전형 지방종은 2 cm 가량의 주위조직을 포함한 광범위 절제를 시행하였고, 나머지 10예에서는 단순 절제를 시행하였다. 술 후 합병증으로 지방종의 크기가 5 cm이상으로 수술 후 수술부의 원위부에 감각저하 및 수술 절개부에 과감각을 호소하는 경우가 1예 있었고 기타 다른 합병증은 없었다. 전화면담이 가능했던 10예 중 재발은 없었다. 결론: 수부에 발생하는 지방종성 종양은 대개 종물감외에는 증상이 없으나 드물게 통증이 나타나는 경우가 있었다. 육안 소견은 비슷하나 조직의 성상은 다양하였다. 수술을 할 경우 합병증의 위험은 적으나 종괴가 클 경우 수술 중 신경손상의 위험이 있으므로 세심한 수술을 해야 할 것으로 사료된다. Purpose: Lipomatous tumor occurred in hand is very rare. There is a broad spectrum of lipomatous tumors including lipomas, variants of lipomas, lipomatosis, liposarcomas and so on. We report the clinical features of 11 cases of lipomatous tumor which occurred in hand. Materials and Methods: Between 1992 and 2008, 11 cases were histologically diagnosed as lipomatous tumor in hand. We reviewed all medical records and clinical photographs retrospectively and ascertained recurrence by telephone interview. Results: Eight cases were ordinary lipomas. Three cases were angiolipoma, fibrolipoma and atypical lipoma respectively. Four cases occurred in finger, two cases in thenar area, two cases in hypothenar area, one case in palm, two cases in wrist. All cases were situated on volar surface. All patients complained of palpable masses. One patient with subungal angiolipoma felt pain. There was no neurologic sign or vascular symptom preoperatively. In one case, postoperative complication (hypoesthesia in $5^{th}$ finger) was developed. There was no local recurrence. Conclusion: In our study, lipomatous tumors occurred in hand did not recur. Patients mainly complained of feeling of lump. Pain was uncommon symptom. Postoperative complication was rare if operation was performed carefully.

자동차 주행 환경에서의 음성 전달 명료도와 음성 인식 성능 비교

이광현,최대림,김영일,김봉완,이용주,Lee Kwang-Hyun,Choi Dae-Lim,Kim Young-Il,Kim Bong-Wan,Lee Yong-Ju 대한음성학회 2004 말소리 Vol.50 No.-

The normal transmission characteristics of sound are hardly obtained due to the various noises and structural factors in a running car environment. It is due to the channel distortion of the original source sound recorded by microphones, and it seriously degrades the performance of the speech recognition in real driving environments. In this paper we analyze the degree of intelligibility under the various sound distortion environments by channels according to driving speed with respect to speech transmission index(STI) and compare the STI with rates of speech recognition. We examine the correlation between measures of intelligibility depending on sound pick-up patterns and performance in speech recognition. Thereby we consider the optimal location of a microphone in single channel environment. In experimentation we find that high correlation is obtained between STI and rates of speech recognition.

Application in Ultrafiltration and Reverse Osmosis Module Set with Acrylic Wastewater Pretreated by Coagulation-Filtration-Neutralization Process

이광현,강병철,이종백,Lee, Kwang-Hyun,Kang, Byung-Chul,Lee, Jong-Baek The Membrane Society of Korea 2008 멤브레인 Vol.18 No.1

After membrane fouling factors in acrylic wastewater were minimized by pretreatment process accompanied with coagulation-filtration-neutralization, it was utilized in UF/RO process. After composing of ultrafiltration and reverse osmosis module set according to types and kinds of membrane, the separation characteristics were examined with the variation temperature and pressure using pretreated acrylic wastewater by membrane module sets. It was found that permeate flux of UF module in module set 4 was about two${\sim}$three times larger than that of UF module in module set 1. Final quantity of permeate from the module set 2 and module set 3 combined with tubular module was shown very good result. It was shown that the removal efficiency of TDS, T-N and COD was very low and was not dependent on the variation of temperature and pressure in all UF modules. The removal efficiency of TDS, T-N and COD was very excellent in RO module. Final water quality of acrylic wastewater was satisfied with effluent allowances limit and membrane module sets were ascertained to reuse wastewater. 아크릴 폐수를 응집-여과-중화의 전처리 공정에 적용하여 막오염 인자를 최소화 한 후 UF/RO 공정에 적용하였다. 막의 형태 및 종류에 따라 한외여과 및 역삼투 모듈을 조합을 이루어 전처리 수를 온도 및 압력변화에 따라 적용하여 분리 특성을 고찰하였다. 투과 플럭스는 모듈 set 1의 UF모듈보다 모듈 set 4의 UF모듈의 투과량이 약 $2{\sim}3$배 더 많이 배출됨을 확인하였다. 최종적인 투과량은 관형모듈과 조합을 이룬 모듈 set 2와 모듈 set 3이 좋은 결과를 나타내었다. 모든 UF 모듈에서 TDS, T-N 및 COD의 제거 효율은 온도 및 압력변화에 영향을 받지 않고 제거 효율 또한 낮음을 알 수 있었다. RO모듈에서 TDS, T-N 및 COD가 우수한 제거 효율을 보였다. 아크릴 폐수의 최종적인 수질결과는 공장폐수의 배출 허용기준을 만족하였고, 막모듈 조합은 폐수의 재활용 가능성을 확인할 수 있었다.

Zero-Configuration을 이용한 무구속 Holter 심전도 데이터 고속 전송 시스템에 관한 연구

이광현,임준우,김영길,Lee, Kwang-Hyun,Yim, Jun-Woo,Kim, Young-Kil 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.2

의료기술의 발달과 인구의 고령화 및 생활양식의 변화로 건강에 관한 관심이 높아지고 있으며, 특히 의료 분야에서 헬스케어에 관한 연구가 활발하게 이루어지고 있다. 이러한 헬스케어 서비스를 제공하기 위해서는 생체 정보 수집센서에 관한 기술, 생체 신호 저장 기술, 저장된 데이터의 전송/분석이 필요하다. 본 연구에서는 이러한 헬스케어 서비스를 제공하기 위해 먼저 사용자의 행동을 보장할 수 있도록 많은 데이터를 저장할 수 있는 무구속 장치를 제안하였다. 그리고 저장된 데이터를 단 시간에 전송할 수 있는 방법에 대하여 연구하고 누구나 활용이 편리하게 자동으로 전송할 수 있는 시스템을 구현한다. Researches of Healthcare have been fulfilled lively with an advanced age and change of lifestyles. Especially, medical field has focused on researches of Healthcare due to that reasons. The Healthcare service requires the foundation technologies, such as sensor aggregating, data saving and data transmitting/analysis. In this research, we proposed the unrestricted equipment which can save a lot of aggregated patient's medical data to guarantee the patient's movement in Healthcare service. Moreover, we research the method which can transmit the aggregated data as soon as possible. Also, we implemented the system which can transmit the patient's medical data automatically for convenient use.

근적외선 연속발진 레이저 조사에 의한 게르마늄 광학창 손상 연구

이광현,신완순,강응철,Lee, Kwang Hyun,Shin, Wan-Soon,Kang, Eung-Cheol 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.1

The damage in germanium (Ge) optical window irradiated by a near-infrared continuous wave (CW) laser was studied. Laser-induced heating and melting process were surveyed, and the specific laser power and the irradiance time to melt were estimated by numerical simulation. The experiments were also carried out to investigate the macro and micro structure change on Ge window. Results showed that the surface deformation was formed by melting and resolidification process, the damaged surface had a polycrystalline phase, and the transmittance as an optical performance factor in mid-infrared region was decreased. We confirmed that an abnormal polycrystalline phase and surface deformation effect such as hillock formation and roughness increase reduced the transmittance of Ge window and were the damage mechanism of CW laser induced damage on Ge window.

자동차 환경에서의 노이즈 DB 및 한국어 음성 DB 구축

이광현,김봉완,이용주,Lee Kwang-Hyun,Kim Bong-Wan,Lee Yong-Ju 대한음성학회 2003 말소리 Vol.48 No.-

Researches into robust recognition in noise environments, especially in car environments, are being carried out actively in speech community. In this paper we will report on three types of corpora that SiTEC (Speech Information TEchnology & industry promotion Center) has created for research into speech recognition in car noise environments. The first is the recordings of 900 Korean native speakers, distributed according to gender, age, and region, who uttered application words in car environments. The second is the collections of mixed noise in 3 car types by model while setting up various noise patterns which can be obtained with the car engine on or off, at different driving speed, and in different road conditions with windows open or closed. The third is the recordings of simulated speech by HATS (Head and Torso Simulator) in car environments with the internal and external noise factors added. These three types of recordings were all made through synchronized 8 channel microphones that are fixed in a car. The creation and applications of these corpora will be reported on in detail.

연속발진 레이저에 의한 공기 유동에 노출된 유리섬유 강화 플라스틱 손상효과

이광현,신완순,강응철,Lee, Kwang Hyun,Shin, Wan-Soon,Kang, Eung-Cheol 한국군사과학기술학회 2015 한국군사과학기술학회지 Vol.18 No.3

We analyzed the damage effect on Glass Fibre Reinforced Plastics(GFRP) under air flow by irradiation of continuous wave near-IR laser. Damage process and temporal temperature distribution were demonstrated and material characteristics were observed with laser intensity, surface flow speed and angle. Surface temperature on GFRP rapidly increased with laser intensity, and the damaged pattern was different with flow characteristics. In case of no flow, penetration on GFRP by burning and flame generation after laser irradiation was appeared at once. GFRP was penetrated by the heat generated from resin ignition. In case of laser irradiation under flow, a flame generated after burning extinguished at once by flow and penetration pattern on GFRP were differently shown with flow angle. From the results, we presented the damage process and its mechanism.

천연 제올라이트와 제올라이트 담체를 이용한 NH₄⁺-N 이온교환 특성 평가

이광현,박민석,주현종,Lee, Kwang Hyun,Park, Min Suk,Joo, Hyun Jong 한국물환경학회 2009 한국물환경학회지 Vol.25 No.5

The ammonium ion exchange characteristics of natural zeolite were investigated to remove ${NH_4}^+-N$. The effect of water temperature, particle size and competitive cation on the exchange capacity was examined. Ammonium ion exchange capacity tended to decrease when the temperature increased from $25^{\circ}C$ to $40^{\circ}C$. Exchange capacity was increased according to the particle size of natural zeolite comes to be small. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir isotherm model or by the Freundlich isotherm model. The ammonium ion exchange capacity ($q_m$) of zeolite carrier can be calculated $11.744mg-{NH_4}^+/g$-carrier. The ion exchange capacity of manufactured zeolite carrier was showed a similar tendency as ion exchange capacity of powder-sized natural zeolite. Therefore, zeolite carrier can be used for increasing of nitrogen removal efficiency in the wastewater treatment plants.

DLBCL 환자의 대사경로 정보를 이용한 생존예측

이광현,이선호,Lee, Kwang-Hyun,Lee, Sun-Ho 한국통계학회 2010 응용통계연구 Vol.23 No.4

마이크로어레이 실험 결과로부터 생존예측지표를 개발하는 일은 관찰 유전자수가 환자의 수보다 훨씬 많고 또 반응변수가 중도절단이 포함된 생존시간이기 때문에 어려운 작업이다. 또한 개별유전자 분석의 문제점이 대두되면서 동일한 대사기능을 수행하는 유전자들의 집합을 대상으로 분석하는 방법이 대두되고 있다. DLBCL 환자들의 마이크로어레이 유전자 발현 자료와 생존시간, 유전자들의 대사경로 정보를 바탕으로 생물학적 해석이 쉬운 생존예측지표를 찾고 그 정확성을 검정하는 pilot study를 실시하였다. 또한 유전자 걸러내기가 지표의 효율성에 미치는 영향력도 비교하여 보았다. Predicting survival from microarray data is not easy due to the problem of high dimensionality of data and the existence of censored observations. Also the limitation of individual gene analysis causes the shift of focus to the level of gene sets with functionally related genes. For developing a survival prediction model based on pathway information, the methods for selecting a supergene using principal component analysis and testing its significance for each pathway are discussed. Besides, the performance of gene filtering is compared.