측창 및 온실 폭이 자연환기 성능에 미치는 영향

이현우,우영회,이종원,Hyun Woo Lee,Young Hoe Woo,Jong Won Lee 국립한국농수산대학교 교육개발센터 2023 현장농업연구지 = Journal of practical agricultural resear Vol.25 No.1

In summer, the natural ventilation performance for varying greenhouse width is very important in the glasshouses for year round cultivation. The effect of the side openings and greenhouse width on natural ventilation performance was analyzed by simulation. The necessary ventilation rate with different solar radiation transmittance increased significantly when the outside temperature grows higher. The necessary ventilation rate of 40% transmittance was about half of that of 90% transmittance. In consequence, shading effect on temperature control in greenhouse is significant in summer. When the total area of the openings for ventilation is constant, the maximum ventilation rate happens when the area of roof openings is equal to the area of side openings. This maximum ventilation rate is about 3 times of that of the greenhouse with roof openings and without side openings. Therefore, the side openings are advantageous to improve the natural ventilation in greenhouses. As the greenhouse width increases, the influence of side openings on the ventilation rate is becoming smaller. If the natural ventilation rate of the greenhouse with roof and side openings is to become double of that of the roof openings only, the width should be narrower than 38.4m for the Venlo type and 64m for Wide span type.

관상동맥우회 이식편으로서의 우위대망동맥의 조직학적 특징

이현우,송현,유동곤,임한중,이재원,송명근,Lee, Hyun-Woo,Song, Hyun,Yoo, Dong-Gon,Lim, Han-Jung,Lee, Jae-Won,Song, Meong-Gun 대한흉부심장혈관외과학회 1999 Journal of Chest Surgery (J Chest Surg) Vol.32 No.10

Long term patency of arterial graft has been better than venous graft and redo coronary artery bypass grafting has been increasing, therefore, there has been an increasing need for alternative arterial grafts except internal thoracic artery(ITA). Material and Method: Right gastroepiploic arteries(RGEA) were harvested from 100 patients who had received gastrectomy for gastric cancer or ulcer. ITAs were obtained from 10 patients undergoing coronary artery bypass grafting. The length of RGEA was measured from the pyloric ring. Items of the morphometric and histologic study at the pyloric ring and sites of the 10cm and 20cm RGEA from the pyloric ring were luminal diameter, intimal thickness, medial thickness, wall thickness, degree of intimal hyperplasia, intimal thickness, medial thickness, wall thickness, degree of intimal hyperplasia, intimal thickness index, medial thickness index, and the number of discontinuities of the internal elastic lamina. Similar items were applied to the proximal site of ITAs. Result: The length of RGEA was 23${\pm}$2.7cm(range 17∼31cm). Comparing the 20cm RGEA with ITA, intimal thickness, medial thickness, wall thickness, and degree of intimal hyperplasia did not show any difference(p>0.05). However, 20cm RGEA was greater than ITA at the luminal diameter, intimal thickness index, and the number thickness and wall thickness in each site of the RGEA(pyloric ring, 10cm, 20cm) decreased from the pyloric ring to the distal sites(p<0.05). The degree of intimal hyperplasia and the number of discontinuities of the internal elastic lamina did not show any difference between the pyloric ring and 10cm, however, those of 20cm were smaller than these sites(p<0.05). RGEA had more number of discontinuities of the internal elastic lamina and rich smooth muscle cells in the media than ITA. Conclusion: The length and diameter of RGEA is good enough to reach most of the coronary arteries. Moreover, long term patency of RGEA may be improved, if anastomosed in the distal site.

석재가공용 다이아몬드 톱의 제조 및 특성

이현우,전우용,이오연,설경원,Lee Hyun-Woo,Jeon Woo-yong,Lee Oh-yeon,Seol Kyeong-won 한국분말야금학회 2004 한국분말재료학회지 (KPMI) Vol.11 No.5

The purpose of the present study is to determine an optimum composition using cheaper powders keeping with high performance of hard rock cutting diamond saw blade. With 50Fe-20(Cu . Sn)-30Co specimen, a part of Co was replaced by Ni(5%, 10%, and 15%, respectively). These specimens were hot pressed and sintered for predetermined time at various temperature. Sintering is performed by two different methods of temperature controlled method and specimen dimension controlled method. In order to determine the property of the sintered diamond saw blade, 3 point bending tester, X-ray diffractometer, and SEM were used. As the Co in the bond alloy was replaced by Ni, the hardness of the specimen increased. Thus the 50Fe-20(CuㆍSn)-15Co-15Ni specimen showed the maximum hardness of 104(HRB). The results of 3 point bending test showed that flexure strength decreased along with increase in Ni content. This is attributed to the formation of intermetallic compound(Ni$_{x}$Sn) determined by X-ray diffraction. The fracture surface after 3 point bending test showed that diamond was fractured in the specimen containing 0%, 5%, and 10%Ni, and the fracture occurred at the interface between diamond and matrix in the specimen containing 15%Ni. The cutting ability test showed that the abrasive property was not changed in the specimen containing 0%, 5%, and 10%Ni. The optimum composition determined in this study is 50Fe-20(CuㆍSn)-20Co-10Ni.

서초동(서울시 서초구)의 거미상

김주필(Joo Pil Kim),정혜리(Hye ri Jeong),김대희(Dae Hee Kim),박동우(Dong Woo Park),서재웅(Jae Woong Seo),이현우(Hyun woo Lee) 한국거미연구소 2017 한국거미 Vol.33 No.1

2016년 3월 31일부터 7월 31일까지 서울특별시 서초구 서초동에 위치한 서울고등학교 교정 일대를 서울고등학교 환경생물부 부원들이 채집 조사한 결과 20과 43속 53종의 거미가 조사 연구되어 이에 보고하는 바이다. From March 31st to July 31st in 2016, members of an environmental biology club at Seoul High School located in Seocho-gu, Seoul, Dae-Hee Kim, Dong-Woo Park, Jae-Woong Seo and Hyun-woo Lee, collected 20 families 43 genera 53 species of spiders and report the result of the study here.

한국어 특성과 CRFs를 이용한 자동 띄어쓰기 시스템

이현우,차정원,Lee, Hyun-Woo,Cha, Jeong-Won 대한음성학회 2008 말소리 Vol.65 No.-

In this work, we propose an automatic word spacing system for Korean using conditional random fields (CRFs) with Korean features. We map a word spacing problem into a classification problem in our work. We build a basic system which uses CRFs and Eumjeol bigram. After then, we analyze the result of inner-test. We extend a basic system added by some Korean features which are Josa, Eomi and two head Eumjeols of word extracting from lexicon. From the results of experiment, we can see that the proposed method is better than previous methods. Additionally the proposed method will be able to use mobile and speech applications because of very small size of model.

연구논문 : 와이블과정을 응용한 신뢰성 성장 모형에서의 MTBF 추정

이현우,김재주,박성현 ( Hyun Woo Lee,Jae Joo Kim,S . H . Park ) 한국품질경영학회 1998 한국품질경영학회 학술대회 Vol.1998 No.12

연구논문 : 시간에 종속되는 스트렝스 - 스트레스 모형연구 - 스트렝스가 변하는 경우 -

이현우,김재주 ( Hyun Woo Lee,Jae Joo Kim ) 한국품질경영학회 1996 품질경영학회지 Vol.24 No.3

이열 하악관(Bifid Mandibular Canal): 방사선적 소견과 임상적 의의 -증례보고-

이현우,김여갑,이백수,권용대,최병준,김영란,Lee, Hyun-Woo,Kim, Yeo-Gab,Lee, Baek-Soo,kwon, Yong-Dae,Choi, Byung-Jun,Kim, Young-Ran 대한치과마취과학회 2009 Journal of Dental Anesthesia and Pain Medicine Vol.9 No.1

When performing the inferior alveolar nerve block anesthesia, surgeon often faced a difficulty of the surgical operation due to the incomplete anesthesia. One of the reason is the variety of mandibular canal anatomy. Up to now, there are some reports of index cases about bifid mandibular canal among mandibular canal anatomic variation, and some classification is applied according to anatomical location and configuration. When surgical operation is performed involving mandible such as dantal implant treatment, extraction of an impacted third molar, sagittal split ramus osteotomy, etc, the position of mandibular canal should be considered. Bifid mandibular canal clinically causes troublesome cases of anesthesia when inferior alvelor nerve block, especially is performed extraction of an impacted third molar. Therefore, It is important for clinicians to recognize the presence of bifid canals on radiographys. Nowadays, the position of mandibular canal can be measured precisely by using Dental CT. It is not found by panorama image but is found by Dental CT sometimes. Among the patients, which take panorama and Dental CT simultaneously, for tooth extraction of lower impacted third molar in our department, we report the case that did not identifying in panorama but identifying it in Dental CT.

고속 공중 무선랜 시스템을 위한 효율적인 연결 요청 제어방법의 성능분석

이현우,김세한,류원,윤종호,Lee Hyun woo,Kim Se han,Ryu Won,Yoon Chong ho 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.3a

본 논문은 무선랜 기술을 활용한 초고속 무선인터넷 서비스에서 사용자 단말의 최대 성능을 얻기 위해 효과적으로 AP를 선택하고 연결을 설정하는 방식에 관한 것이다. IEEE 802.11에 기반한 공중 무선랜 환경에서 AP의 탐색과정을 수동형과 능동형으로 분류하고, 본 논문에서는 수동형 AP탐색 과정은 무선랜 접속장치(AP:Access Points) MAC계층에서 단말에 미디어 접근정보를 방송으로 알려주는 비콘(Beacon)프레임을 이용하고, 능동형 AP 탐색과정에서는 AP의 조사응답(Probe Response) 메시지 프레임을 이용하여 무선랜 단말에게 현재 AP에 연결(association)되어 있는 단말 갯수와 처리중인 트래픽량을 알려주는 방식을 제안한다. 단말에서는 RSSI, AP에 연결된 단말의 갯수와 처리하는 트래픽량의 정보를 종합적으로 검토하여 효율면에서 가장 유리한 AP를 선택하여 연결을 설정하면 다수의 사용자가 동시에 사용하는 핫스팟 환경에서도 최대성능을 얻을 수 있으며, 사업자입장에서는 사용자의 분산으로 자원과 망 관리 효율 면에서 상당한 효과가 있음을 시뮬레이션을 통하여 검증하였다. This paper generally relates to the field of wireless local area networks(WLANs), and more particularly, to AP selection and association methods for the performance of a station. In these days, IEEE 802.11 Wireless LAN network is widely deployed and used as an emerging service to connect high-speed Internet in the public wireless environment. But, if there are many users in hot spot area, they suffer a severe decrease of performance. Thus it needs an association and access control mechanism especially when it is used in the public environment. In this paper, we suggest a selection and association method using Beacon or Probe Response frames based IEEE 802.11. Station selects AP using the information of the capacity area in a Beacon or a Probe Response frame. According to the present paper, an association method for a public WLAN service, which includes a WLAN user terminal and an AP for relaying WLAN communications to and from the user terminal, includes the steps of the user terminal asking the AP's states for access to a radio channel; and the station selects and associates with the AP According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

건축물 설계변수의 상관관계 분석을 통한 CO₂ 배출저감 방안

이현우,채민수,Lee, Hyun-Woo,Chae, Min-Su 한국태양에너지학회 2011 한국태양에너지학회 논문집 Vol.31 No.1

This study proposes a $CO_2$ emission reduction method through correlation analysis of a sample building. First, energy saving factors of heating, cooling, lighting were determined for the correlation analysis and $CO_2$ emission contribution rate of the design parameters have been analyzed. Then optimal combination of each design parameter has been drawn. Heat transfer coefficient of walls and windows, air permeability, windows area ratio, and shading devices were selected as applicable energy saving factors of the sample building. Also computer simulation was conducted using experimental design by Orthogonal Arrays of the statistical method. And the contribution rate was estimated by Analysis of Variance-ANOVA. As a result, the $CO_2$ emission in heating was reduced to 51.9%; in cooling to 16.8%; and in lighting to 2% compared to the existing building. The majority of the reduction was presented by heating energy.