• 한국전자파학회논문지
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• 제22권4호
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• pp.453-461
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• 2011

방송 대역의 한정된 주파수 자원을 보다 효율적으로 사용하고, 지상파 방송의 난시청 지역 해소와 방송 품질 향상을 위해 중계기의 중요성은 계속적으로 증가하고 있다. 그러나 OFDM 시스템의 T-DMB 동일 채널 중계기는 전송된 신호의 일부가 궤환되어 다시 수신 안테나에 입력되는 궤환 간섭 신호가 발생하고, 위상 잡음(phase noise)으로 인한 ICI(Inter Carrier Interference)가 증가하여 등화기에 심각한 영향을 미친다. 그러므로 본 논문에서는 상관도를 적용한 LMS(Least Mean Square)를 이용하여 궤환 간섭 신호를 제거한다. 또한, 전력 증폭기(high power amplifier)의 백-오프 특성과 위상 잡음에 의해 발생하는 ICI를 제거할 수 있는 효과적인 등화 알고리듬을 제시한다. 시뮬레이션 결과를 통하여 back-off=9 dB 상태에서 위상 잡음 -20 dBc의 경우 위상 잡음을 보상하여 SNR=14 dB 이하에서 BER=$10^{-4}$의 성능을 만족할 수 있다.

• 수산경영론집
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• 제24권2호
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• pp.1-16
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• 1993

Because of the radical changes in the domestic and foreign economic circumstances Koreaa fisheries is confronted with difficulties. Along the end of the UR marine products of other nations are rushing into Korea. Also migration of labor to other industries and rise of wage level in Korean fisheries deteriorate managerial conditions. But in Korea which has little natural resourses fisheries is still more important. That is \circled1 creating job opportunites \circled2 increase of income \circled3 supply of foodstuffs and animal protein \circled4 acquisition of foreign currency \circled5 enlargement of domestic market for industrial products \circled6 development of other interrelated industries \circled7 rational use of domestic resourses \circled8 diversification of population and production activites \circled9 contribution to balanced growth of national economy by the developing regional economy. These roles of fisheries in national economy mentioned above are to be excuted forward. In spite of the radical change in the economic circumstances at the end of the UR fisheries if crucial in Korea as a industry. For this our fisheries is to be made to compete with foreign fisheries. Through the cheap price and high quality our fisheries must be came to compete with foreign fisheries and meet the people's needs for marine products. For this it is necessary to maintain high productivity and competitive power. Now with the exception of a portion of the deep - sea fishing, our fisheries is generally paltry, Especially inshore fishery which is the main stock in our fisheries is very paltry and so productivity and competetive power are very low. So to develop our fisheries which has s comparative disadvantage active polices that follows below are to be promoted on a large scale. \circled1 improvement of structure \circled2 augmentation of productivity in fishing ground by making fisheries resourses \circled3 enlargement of finantial and monetary assistance \circled4 effective administration of fisheries cooperative union \circled5 activation of R&D etc These polices which need to be scientific and comprehensive are very valuable. Especially without making fishieries resources we cannot expect economy of scale, promotion of productivity and development of fisheries. And we do also endeavour to gather the results of the study and investigation about fisheries domestic and foreign and do ceaselessly put these to practical use systimatically.

• Journal of Biosystems Engineering
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• 제9권2호
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• pp.65-73
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• 1984

While most of researches on the performance of high temperature grain dryer have dealt mainly with improving dryer capacity and drying speed during the last twenty years, energy efficiency, in fact, has not been emphasized. Current fuel supplies and energy cost have shifted the emphasis to reducing the energy consumption for grain drying while maintaining dryer capacity and grain quality. Since the energy input for drying is relatively large, the recovery and reuse of at least part of the exhaust energy can significantly reduce the total energy consumption in existing drying systems. Unilization of exhaust heat in grain dryer either through direct recycling or by a thermal coupling in heat exchanger have been subject of a number of investigators. However, very seldom research in Korea has been done in this area. Three drying tests(non-recycling, 0.22 recycle ratio, and 0.76 recycle ratio)were performed to investigate the thermal efficiency and heat loss factors of continuous flow type dryer, and to analyze the effect of recycle ratio (weight of exhaust air recycled/total weight of input air) on the energy requriements for rough rice drying. The test results showed that when the exhaust air was not recycled, the energy lost from furnace was 15.3 percent of input fuel energy, and latent and sensible heat of exhaust air were 61.4 percent and 11.2 percent respectively. The heat which was required in raising grain temperature and stored in dryer was relatively small. As the recycle ratio of exhaust air was increased, the drying rate was suddenly decreased, and thermal efficiency of the kerosene burner was also decreased. Drying test with 0.76 recycle ratio resulted in 12.4% increase in fuel consumption, and 38.4% increase in electric power consumption as compared to the non-recycled drying test. Drying test of 0.22 recycle ratio resulted in 6.8% saving in total energy consumption, 8.0% reduction in fuel consumption, and 2.5% increase in electric power consumption as compared to the non-recycled drying test.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.632-636
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• 2006

기지국 및 중계기를 통한 다양한 무선 통신 서비스 및 통화품질 개선을 위해서는 사용 환경과 계절 및 시간대에 따른 전파의 특성과 차량 및 고객의 유동 특성 등을 감안한 기지국 안테나의 셀 영역 제어가 필요하다. 본 논문은 사용 환경 조건에 따라 특정 방향으로 지향 이득을 제어하여 빔 스캔 특성을 얻을 수 있는 이중 대역 기지국 안테나 시스템을 제안하고 이를 구현하였다. 제작된 안테나의 방사부는 5.8GHz 대역의 ITS용 $1\times3$ Sub-Array 2개와 2.3GHz 대역의 WiBro용으로 Single 방사소자 2개로 구성된다. 각각은 ITS용 13dBi, WiBro용 12dBi의 이득을 얻었다. RF Mdodule은 스위치, 증폭기, PAD, 3-Bit 위상천이기, Power Divider로 구성했다. 위상은 $45^{\circ},\;90^{\circ},\;180^{\circ}$의 3-Bit 위상 천이기를 사용함으로써, 빔 스캔 범위는 ITS용으로 $0^{\circ}$에서 최대 $19^{\circ}$까지, WiBro용으로 $0^{\circ}$에서 최대 $45^{\circ}$까지 전자식 제어가 가능하도록 설계하였고, 제작 측정하여 설계치와 비교 분석하였다.

• 한국ITS학회 논문지
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• 제11권5호
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• pp.89-96
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• 2012

본 논문에서는 인터디지털 헤어핀 공진기를 이용하여 UTIS (도시 교통 정보 시스템)에 사용 가능한 저 위상잡음 발진기를 설계 및 제작하였다. 인터디지털 헤어핀 공진기는 기존의 소형화된 헤어핀 공진기에 인터디지털을 접목시켜 공진기의 물리적인 크기를 기존 대비 약 70%로 축소시켰고, 고조파 특성을 향상시켰다. 또한 132 의 높은 Q 값은 저 위상잡음 발진기 설계에 적합하다. UTIS 용 저 위상잡음 발진기는 5.75 GHz에서 출력 12 dBm 의 전력과 100 kHz offset 에서 -100.8 dBc/Hz 의 낮은 위상잡음을 얻었다. 이는 기존의 헤어핀을 이용한 발진기에 비해 12 dB 정도의 개선을 보여준다.

• 방송공학회논문지
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• 제15권6호
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• pp.757-767
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• 2010

본 논문은 3차원 TV 시청에 있어서, 2차원에서와 같은 색감을 최대한 제공하기 위한 방법을 연구하였다. 이를 위하여 입력 RGB 색상 막대(color bar) 영상을 기준으로 2차원과 3차원 재생시 재현되는 RGB 강도의 입출력 관계를 모델링하였으며, 이를 근거로 2차원 대비 보정되어야 할 3차원 색상 사상표(mapping table)를 생성하였다. 생성된 사상표를 기존 3차원 TV 시스템의 출력부에 추가하여, 일반 2차원 재생시에는 입력 영상을 우회(bypass)하도록 하고, 3차원 재생시 색상 보정 과정을 수행하도록 하여 3차원 재생시에도 2차원에서 느낄 수 있는 색감을 재현할 수 있도록 하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.355-360
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• 2002

ElectroSlag Strip Overlaying (ESSO) process has been around since 1970. ESSO process had limited acceptance due to a few problems associated with the use of this process in its very early stage. Limited knowledge and, most significantly, poor quality of the equipment and welding flux gave the ESSO process a bad name. However, this process is well accepted today and used in North America, Europe and Japan. The ESSO process provides low dilution overlays at high deposition rates, excellent and consistent deposit chemistry with excellent surface quality, and virtually no defects. Capitan has taken this process one step further through extensive research and development of the process itself as well as the equipment. The improvement brought to the process warranted the issuance in May 2000 of an US patent. This study demonstrates the feasibility of this process with immediate positive production results. The main achievements of this work are as follows: $\textbullet$ Development of six various strip-flux combinations on three different base materials: carbon steel, $\frac{1}{4}$ Cr/.5 Mo and 2 $\frac{1}{4}$ Cr/l Mo, fully tested with: penetrant, ultrasound, bends, hardness, overlay chemistry, corrosion and hydrogen disbonding. $\textbullet$ 12" dia. 90 hot formed elbows from straight pipe electroslag overlayed with "1 layer" and "2 layer" Alloy 625 $\textbullet$ a very unique development of miniaturized overlaying equipment able to perform overlay in pipe with diameters as low as 10" (254 mm). This development has large applications in the field of offshore, petrochemical, refining, pulp and paper and power generation industries. The aftermath of this development was its immediate acceptance by major end users with the completion of four projects of overlayed pipe in the USA and Far East Asia.

• 한국음향학회지
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• 제39권2호
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• pp.113-119
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• 2020

자동차에서의 모터 사용 증가로 자동차 실내 음질(sound quality) 향상을 위해 모터 소음이 주요 관심사이다. 본 연구의 목적은 부하변화에 따른 모터 소음 성능을 나타낼 수 있는 인자를 제안하는 것이다. 이를 위하여, 파워스펙트럼과 라우드니스가 소음 성능을 나타내는데 적합하지 않음을 확인하였고, 브러쉬 마찰 성분과 관련된 부분라우드니스(PN_B)와 토크 리플 성분과 관련된 부분라우드니스(PN_R)가 소음 성능을 나타내는 인자로 파악되었다. 그리고 PN_B와 PN_R를 이용하여 부하에 따른 모터 소음의 변화 특성을 나타내기 위한 방법으로 모터 소음 성능 곡선을 제안하였다. 이 곡선은 소음 제어, 모터 선정 및 시스템 개선을 위한 가이드로 활용될 것으로 기대된다.

• 한국응급구조학회지
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• 제15권2호
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• pp.27-42
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• 2011

Purpose: This study intended to improve quality of prehospital emergency care for trauma patients by figuring out its current situations and problems based on run-sheets and questionnaires of 119 emergency medical technicians (EMTs). Methods: This study conducted a research of 425 trauma patients transferred to the 3rd hospital in G-city by 119 ambulances from July 1, 2008 to June 30, 2009. We aslo utilized 114 copies with questionnaires of 119 EMTs working in J-province. The data were analyzed with SPSS 18.0. Results: There were 425 trauma patients including 272 men and 137 patients with traffic accident. When it comes to types of 119 EMTs who delivered cares to patients, there were 206 (48.5%) advanced EMTs, 101 (23.8%) basic EMTs, 50 (11.8%) nurses and 43 (10.2%) rescue education receivers. The most frequent measured vital sign was pulse rate (54.1%). Regarding assessment of systolic blood pressure, pulse rate and respiration rate, there were some significant differences in accordance with type of 119 EMTs. Among the 317 patients evaluated 'emergency' in field, 137 patients returned to their home. Prehospital emergency cares accounted for 861, around 2.0 treatments per a patient. In view of questionnaire, the 74.6% of 119 EMTs hoped supplement of man power for proper prehospital care to trauma patients. Conclusion: This study suggested that it is necessary to develop detailed guidelines for trauma patients so as to improve quality of trauma patient evaluation and prehospital care. Furthermore, improvement of emergency care systems will reduce mortality of trauma patients and lead to their good outcome.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2002년도 춘계 국제 학술대회
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• pp.23-25
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• 2002

This study was conducted to understand characteristics of wastewater which is discharged from small-scale dyehouse located in Seoul downtown area and to Find the appliable treatment method on the spot. The results of this study were summarized as followings. 1. The method which is used at present is mostly flocculation by coagulant or fenton oxidation. But the treatment efficiency of them are not good. 2. The results of fenton oxidation experiment demonstrated that treatment efficiency of COD was limited, which showed the need of the additional process or the improvement of existing treatment method, while the color was reduced considerably in optimal condition. 3. The optimal condition of fenton oxidation are as followings. -Feasible pH was in the 3∼4 regardless of the kinds of iron ions, But the fluctuation of treatment efficiency with the change of pH was small - The mass ratio of H$_2$O/CODcr was used to evaluate the parameter of H$_2$O$_2$ The optimal range of this was in 0.7∼1,3 and it was observed that the ratio got higher as the quality got worse. -For iron ion, FeCl$_2$4H$_2$O turned out to be more effective for removal of color compared with was compared FeSO$_4$7H$_2$Oin. the mass ratio of Fe/H$_2$O$_2$ of 2.3∼2.8 for of FeSO$_4$7H$_2$O and 1.6∼1.8 for FeCl$_2$4H$_2$O resulted in good treatment efficiencies. 4. With adsorption process applied before fenton oxidation in order to treat the high concentration wastewater, the treatment efficiency increased by 61％ in CODcr, 55％ in color. and if the power activated carbon is injected in more than 2500mg/$\ell$, the wastewater can be treated within the effluent quality criteria.