가성소다(NaOH) 용액을 이용한 선상 이산화탄소 포집 장치의 선박 검증시험

이광현,노형주,이민우,손원경,정재열,김태홍,남병탁,김재익 대한조선학회 2024 大韓造船學會 論文集 Vol.61 No.1

Hi Air Korea and Hanwha ocean are currently developing an Onboard Carbon dioxide Capture System (OCCS) to absorb CO2 emitted from ship's engine using a sodium hydroxide(NaOH) solution, and converting the resulting salt into a solid form through a chemical reaction with calcium oxide (CaO). The system process involves the following steps; 1)The reaction of CO2 gas absorption in water, 2)The reaction between carbonic acid (H2CO3) and NaOH solution to produce carbonate or bicarbonate, and 3)The reaction between carbonate or bicarbonate and CaO to form calcium carbonate (CaCO3). And ultimately, the solid material, CaCO3, is separated and discharged using a separator. The OCCS has been installed on an ship and the test results have confirmed significant reduction effects of CO2 in the ship's exhaust gas. A portion of the exhaust gas emitted from the engine was transferred to the OCCS using a blower. The flow rate of the transferred gas ranged from 800 to 1384 ㎥/hr, and the CO2 concentration in the exhaust gas was 5.1 vol% for VLSFO, 3.7 vol% for LNG and a 12 wt% NaOH solution was used. The results showed a CO2 capture efficiency of approximately 42.5 to 64.1 vol% and the CO2 capture rate approximately 48.4 to 52.2kg/hr. Additionally, to assess the impact of the discharged CaCO3on the marine ecosystem, we conducted “marine ecotoxicity test” and performed Computational Fluid Dynamics (CFD) analysis to evaluate the dispersion and dilution of the discharged effluent.

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.

구강암종 세포주에서 은행잎 추출물(EGb 761)의 세포고사 효과

이광현,권순호,서형석,김경수,윤주헌,이주환 대한이비인후과학회 2005 대한이비인후과학회지 두경부외과학 Vol.48 No.3

Background and Objectives:To examine the chemopreventive efects of Ginkgo biloba extract (EGb 761) on oral cavity cancer, we investigated the apoptosis of oral cavity cancer cells by EGb 761 and the apoptotic pathway involved. Materials and Method:SCC 1483 cancer cell line derived from a human retromolar trigone carcinoma was used. Inhibition of proliferation was examined by proliferation assay. Apoptosis was measured and confirmed by flow cytometry, DNA fragmentation asay and Western blotting with PARP antibodies. The involvement of the caspase cascade was investigated by co-treating with the caspase inhibitor, z-VAD-fmk. Results:The inhibition of SCC 1483 cells was noted from 250 μg/ml of EGb 761. Apoptosis was observed after 24 hours of incubation with 250 μg/ml EGb 761 and it occured in a time-dependent manner. Apoptosis was confirmed by DNA fragmentation and PARP cleavage. Co-treatment with z-VAD-fmk inhibited apoptosis and PARP cleavage by EGb 761. Conclusions:EGb 761 induces the apoptosis of SC 1483 cells and the caspase cascade is involved in this apoptosis. Therefore, EGb 761 may be used as a chemopreventive agent in oral cavity cancer. Further studies are required on the clinical use of EGb 761.

재형상 비행제어기 구현을 위한 가변 가중치 의사역행렬 조종배분 알고리즘

이광현,방효충 한국항공우주학회 2007 한국항공우주학회 학술발표회 논문집 Vol.- No.-

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.

지능망에서의 이동 에이전트를 이용한 과부하제어 메커니즘에 관한 연구

이광현,박승균,박주희,오영환 한국통신학회 2002 韓國通信學會論文誌 Vol.27 No.7

전통적인 지능망 부하제어에서 개별적인 SCP(Service Control Point) 보호가 주요 관점이었다면, 본 논문에서는 지능망 전체 네트워크 자원 활용의 최적화를 통한 부하제어를 주요 관점으로 하였다. 이는 이동 에이전트 기술의 이용으로 가능해 지는데 이동 에이전트는 실행환경이 구현된 모든 시스템으로의 이동이 가능하고 독자적으로 작업 수행이 가능한 소프트웨어이다. 본 논문에서는 이동 에이전트를 이용한 과부하 제어 메커니즘과 이동절차를 제안하였다. 제안한 이동 에이전트를 이용한 과부하 제어 메커니즘은 이동 에이전트를 이용해 서비스 특성에 따른 지능망 과부하를 제어할 수 있고 이동 절차는 지능망 부하 변화에 따른 이동 에이전트의 이동 방법이다. 시뮬레이션결과 제안한 메커니즘은 기존 Call Gapping메커니즘보다 SCP 부하율과 시도 호 실패 수에서 우수한 성능을 보였으며 SCP과부하 시 SS NO.7 네트워크 트래픽의 감소를 가져왔다. In traditional approaches to IN load control, there has been a focus on the protection of individual SCPs. On the other hand, the load control of network level can be achieved by using a mobile agent technology, which is a software element responsible for moving from one system to another and performing their task. In this thesis, we propose an mobile agent mechanism and two mobile agent migration procedures and analyze the performance of the Call Gapping mechanism and the mobile agent mechanism. The mobile agent mechanism showed that the SCP load control rate and attempt the number of attempted call failure were better than those of Call Gapping mechanism. Also, the amount of SS NO.7 traffics was reduced in the case of an overload condition.

저전력 설계를 위한 면적 절약형 곱셈기 구조에 관한 연구 ( A Hardware Reduced Multiplier for Low Power Design )

이광현,임종석 대한전자공학회 1998 대한전자공학회 학술대회 Vol.1998 No.11

한국인의 소르빈산 및 안식향산 섭취수준 평가

이광현,김애영,최성희,임호수,최재천,김미혜,김소희,하상도 한국식품위생안전성학회 2013 한국식품위생안전성학회지 Vol.28 No.4

In this study, sorbic acids and benzoic acids frequently used in foods retailed in Korea were monitored and their estimated daily intakes were assessed for a purpose to ensure food additives safety management. The estimated daily intakes were calculated by categorizing the assessment items into the national average, by gender, by age and the high intake (95th) groups based on concentrations of preservatives in foods as well as national health and nutrition survey data. The calculations were then compared with the ADI of the JECFA and the possibility of risk to be imposed on the people was examined. The results indicated that the estimated daily average intakes of preservatives were 221.60 μg/kg·bw/day of sorbic acids and 27.30 μg/kg·bw/day of benzoic acids. Compared to the ADI, the intake levels were 0.89 and 0.55% respectively, which were in a safe range. The estimated daily intakes of sorbic acids and benzoic acids in the high intake group (95th) were 1140.27 μg/kg·bw/day and 194.95 μg/kg·bw/day, which were 4.56% and 3.90% of the ADI (%) respectively, indicating that the intake levels of sorbic acids and benzoic acids in the high intake group were within a safe range. As for gender difference, the amount of benzoic acids intake was slightly larger in men than in women. However, gender differences were not observed in terms of the intake of sorbic acids. In terms of the levels of intake by age, the rates were found to be in the range of 0.52-2.10% for sorbic acids and 0.15-1.23% for benzoic acids. Therefore, the levels of sorbic acids and benzoic acids intakes were found not to exceed the ADI in all groups, and thus were within the safe ranges. 본 연구는 식품첨가물의 안전관리확보를 위해 국내 식품 중 사용빈도가 높은 소르빈산류 및 안식향산류를 대상으로 모니터링을 한 후 일일추정섭취량을 평가하였다. 일일추정섭취량은 식품 중 보존료의 농도와 국민건강·영양조사 자료를 이용하여 국민평균, 성별·연령별 상위섭취자(95th) 그룹으로 분류하여 산출하였고, 이를 JECFA에서제시한 ADI와 비교하여 국민의 섭취 수준을 확인하였다. 그 결과 분석된 보존료의 국민평균 일일추정섭취량은 소르빈산류 221.60 μg/kg·bw/day, 안식향산류 27.30 μg/kg·bw/day로 산출되었으며, ADI 대비 각각 0.89, 0.55% 로섭취수준은 안전한 것으로 확인되었다. 상위섭취자(95th)의소르빈산류 일일추정섭취량은 1140.27 μg/kg·bw/day로ADI 대비 4.56%, 안식향산류 일일추정섭취량은 194.95 μg/kg·bw/day로 ADI 대비 3.90% 수준으로 소르빈산류 및안식향산류의 상위섭취자 섭취수준도 안전한 것으로 평가되었다. 성별에 따른 차이는 안식향산류의 경우 남자가 여자보다 조금 높았으나 소르빈산류는 성별에 따른 차이를보이지 않았다. 연령별 섭취수준은 소르빈산류 0.52~2.01%,안식향산류 0.15~1.23% 로 평가되었다. 따라서 모든 그룹에서 소르빈산류 및 안식향산류의 섭취수준은 ADI를 초과하지 않아 안전한 것으로 평가되었다.

DCF내의 여러 모드를 이용한 새로운 Tunable Fiber-Optic Microwave Filter

이광현,최우영,최상수,오경환 한국통신학회 2002 한국통신학회 기타 간행물 Vol.2002 No.10

카올린나이트로부터 중기공성 ${\gamma}-Al_2O_3$의 제조 및 특성

이광현,고형신,김윤섭,Lee, Gwang-Hyeon,Go, Hyeong-Sin,Kim, Yun-Seop 한국재료학회 2000 한국재료학회지 Vol.10 No.12

국내산 kaolinite를 소성한 다음 실리카를 선택적으로 추출하여 중기공성 ${\gamma}-Al_2O_3$를 제조하였다. $1000^{\circ}C$에서 24시간 소성된 kaolinite는 소량의 무정형 실리카와 ${\gamma}-Al_2O_3$으로 이루어진 스피넬 상의 미세구조로 전이되었음을 확인하였다. 다공성 ${\gamma}-Al_2O_3$는 $25~90^{\circ}C$의 반응온도, 0.5~4h의 추출시간 및 1~8M의 KOH 농도범위에서 무정형 실리카를 선택적으로 용해하여 제조할 수 있었다. $90^{\circ}C$, 1시간 및 4M의 KOH 농도조건에서 얻어진 ${\gamma}-Al_2O_3$는 약 $40~80{\AA}$ 정도의 매우 좁은 하나의 기공크기 분포를 가지고 있었으며, mesopore의 기공이 많이 생성되었다. 비표면적은 $250\textrm{m}^2/g$이고, 총 기공부피는 $0.654\textrm{cm}^3/g$로 나타났다. Mesoporous ${\gamma}-Al_2O_3$ has been prepared by selective leaching of silica from calcined domestic kaolinite. From XRD and TG-DTA data, it was found that the microstructure of a spinel phase, consisting of ${\gamma}-Al_2O_3$ containing a small mount of amorphous silica, was obtained by calcining kaolinite samples at around $1000^{\circ}C$ for 24h. Porous ${\gamma}-Al_2O_3$ was prepared by selectively dissolving the amorphous silica in KOH solutions of 1~4M at temperatures of $25~90^{\circ}C$ for leaching time of 0.5~4h. In the case of the ${\gamma}-Al_2O_3$ obtained upon KOH treatment of 4M at $90^{\circ}C$ for 1h, it showed a very narrow unimodal pore size distribution, and also formed much mesopore at a diameter of around $40~80{\AA}$. The specific surface area was $250\textrm{m}^2/g$ and the total pore volume was $0.654\textrm{cm}^3/g$.