• 대한전자공학회논문지TE
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• 제42권1호
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• pp.35-40
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• 2005

최근 들어 이동 통신에서 이동하는 고객의 위치정보와 관련된 서비스가 중요하게 부각되고 있다. 이동 객체의 경우 갱신 연산이 많고 부하가 특정 지역에 집중되는 특징이 있다. 이러한 LBS 응용에서 시공간 영역질의는 중요한 부분이고, 질의 처리속도의 개선을 위해서 디스크 입출력 시간을 최대한 줄일 필요가 있다. 본 논문에서는 갱신연산을 최소화하기 위해 고안되어진 시공간 인덱스 구조로 비 균등 2단계 격자 인덱스 구조를 적용한다. 또한 질의 처리률 향상을 위해서 공간 관련성과 시간 관련성을 이용한 스케줄링 기법과 time zone 개념을 사용하여 시공간 개념이 결합된 질의 처리 기법을 제안한다. 다양한 질의 범위를 사용하여 실험한 결과 제안된 방법이 기존의 방법보다 우수함을 알 수 있었다.

• 대한수의학회지
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• 제30권4호
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• pp.473-478
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• 1990

This survey was conducted to observe the prevalence of blood parasites in slaughtered cattle included Korean native cattle, Charolias, Hereford, Aberdeenangus and Holstein breeds in the Western area of Kyeongnam. The results obtained are summarized as follows: 1. The prevalence of T sergenti was shown 71.8% as 395 heads of a total of 550 heads examined and from Jaunary to November the monthly prevalence of T sergenti was shown the range of 61.1% to 84% except 38.5% in December. The other blood parasites included Babesia and Anaplasma were not detected from the blood samples except Setaria spp microfilariae. 2. The distribution of parasitaemia levels of T sergenti in positive cattle was shown 93.9% in the range of 1~10/1000 rbc, 4.1% in 11~20, 1.3% in 21~30 and 0.8% above the range of 31. 3. The pervalence of T sergenti by breeds of slaughtered cattle was shown 71.2% in Korean native cattle, 72.7% in Charolias, 78.3% in Hereford and 81. 8% in others (Aberdeen-angus and Holstein) respectively. Also the parasitaemia levels in these cattle were shown higher levels in imported cattle included Charolias, Hereford, Aberdeen-angus and Holstein breeds comparing with Korean native cattle. 4. The prevalence of Setaria spp microfilariae in slaughtered cattle was shown 6.9% and by monthly prevalence of the parasite was shown higher in March, April and May compared with June, July, August and October. But in the winter season included January, February, November and December the parasite was not detected from the blood samples. 5. The distribution of parasitaemia levels of Setaria spp microfilariae per ml of blood was shown 65.8% in the range of 1~50, 13.2% in 51~100 and 10.5% in 101~200 and above the range of 201, respectively.

• 대한원격탐사학회지
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• 제34권4호
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• pp.661-670
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• 2018

This study aims to develop a methodology of convolutional neural networks (CNNs) to produce thematic maps from remote sensing data. Optimizing the image size for CNNs was studied, since the size of the image affects to accuracy, working as hyper-parameter. The selected study area is Mt. Ung, located in Dangjin-si, Chungcheongnam-do, South Korea, consisting of both coniferous forest and deciduous forest. Spatial structure analysis and the classification of forest type using CNNs was carried in the study area at a diverse range of scales. As a result of the spatial structure analysis, it was found that the local variance (LV) was high, in the range of 7.65 m to 18.87 m, meaning that the size of objects in the image is likely to be with in this range. As a result of the classification, the image measuring 15.81 m, belonging to the range with highest LV values, had the highest classification accuracy of 85.09%. Also, there was a positive correlation between LV and the accuracy in the range under 15.81 m, which was judged to be the optimal image size. Therefore, the trial and error selection of the optimum image size could be minimized by choosing the result of the spatial structure analysis as the starting point. This study estimated the optimal image size for CNNs using spatial structure analysis and found that this can be used to promote the application of deep-learning in remote sensing.

• 정보처리학회논문지D
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• 제11D권4호
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• pp.835-844
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• 2004

최근 들어 이동 통신 분야에서 이동하는 고객을 위한 위치 기반 서비스가 중요한 서비스로 부각되고 있다. 이동객체 응용의 경우 갱신 연산이 많고, 부하가 특정 지역에 집중되는 특징이 있다. 윈도우 나 원형 형태의 범위질의는 위치 기반 서비스에서 중요한 질의 중 하나이다. 이러한 범위질의에서는 부분 포함된 셀과 완전 포함된 셀을 구분해야할 필요가 있다. 또한 올바른 한정된 객체를 골라내기 위해 시간 영역을 고려할 필요성이 있다. 본 논문에서는 갱신연산을 최소화하기 위해 고안되어진 2번째 단계에 고정 그리드 구조를 적용한 2단계 인덱스 구조를 적용한다. VP 필터링과 윈도우 셀 필터링 기법을 이용한 공간 셀 필터링 기법과 Time Zone 개념을 사용하여 시공간 개념이 결합된 필터링 기법을 제안한다. 제안된 방법의 성능 측정을 위해서 다른 필터링 조합을 가지고 다양한 윈도우 질의와 원 질의에 대해서 실험 결과를 보인다.

• 한국추진공학회지
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• 제24권6호
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• pp.16-27
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• 2020

넓은 비행영역에서 스크램제트 엔진의 운용을 위해, 비행 조건의 변화에도 안정적인 성능을 나타내는 흡입구의 설계가 중요하다. 본 연구에서는 마하수 4~6, 받음각 -6도~6도의 넓은 비행영역에서 안정적인 성능을 얻기 위한 2D 고정형 흡입구의 설계 방법에 대한 연구를 수행하였다. 설계 방법 및 설계 주안점에 대해 제시한 후, 넓은 비행영역에서 높은 전압력 회복율과 유량 포획율을 갖는 흡입구를 설계함에 있어 가장 중요한 설계요소인 초기 압축각도와 비행 마하수 설계점에 따른 성능예측 및 분석을 수행하였다. 분석 결과를 바탕으로 넓은 비행영역에서 안정적인 성능을 나타내기 위한 두 가지 주요 설계요소의 선정기준을 제시하였다.

• 한국지형학회지
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• 제27권3호
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• pp.41-51
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• 2020

This study tried to reveal incision rate distribution of streams on the northern part of the Sobaek Mountain Range with OSL age dating and geomorphic analysis, and factors influencing on the distribution were also discussed. With results from the previous studies, a total of 10 sites from 7 streams in the study area showed the rates ranging from 0.220 m/ka to 0.297 m/ka. Namhan-gang and Geum-cheon indicated the highest and lowest rates, respectively. Both sides in the northern section in the study area showed similar rates, while the western side in the middle section and the eastern side in the southern section showed higher rates than the other sides. Higher rates were also found from the eastern and northern sides where the Range runs N-S and E-W directions, respectively. Certain relationships with altitude and distance from the divide can be recognized from the rates and may be attributed to active incision with altitude and location of the uplift axis near the present divide. The rates on granite and sedimentary rock were higher than those on metamorphic rock, indicating that bedrock type is one of the important factors influencing on stream incision. Tectonic movement seemed to play some roles in the rates, because areas with lineaments showed lower rates. This study suggests that incision rate distribution of streams on the northern part of the Sobaek Mountain Range reflects various local geomorphic and geologic conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.167-168
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• 2009

The noise sources in ship and offshore structure have an influence on adjacent receiving area through a partition between noise sources and receiving area. The partition in ship is usually made of stiffened plate. Sound transmission loss (STL) of the partition at high frequency could be improved by additional installation of insulation or wall panel. At low frequency, however, it is very difficult and needs an increase of plate thickness which causes a considerable weight increase of ship. In this paper, we have investigated the effect of the bulkhead boundary condition. From measurement result, we found that the bulkhead boundary condition can affect a lot in STL, especially at low frequency range. Finally, we get the 5dB increase in STL through the modification of boundary condition.

• ETRI Journal
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• 제31권5호
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• pp.601-603
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• 2009

This letter presents a high performance 2.4 GHz two-stage power amplifier (PA) operating in the temperature range from $-30^{\circ}C$ to $+85^{\circ}C$ for IEEE 802.11g, wireless local area network application. It is implemented in InGaP/GaAs hetero-junction bipolar transistor technology and has a bias circuit employing a temperature compensation technique for error vector magnitude (EVM) performance. The technique uses a resistor made with a base layer of HBT. The design improves EVM performance in cold temperatures by increasing current. The implemented PA has a dynamic EVM of less than 4%, a gain of over 26 dB, and a current less than 130 mA below the output power of 19 dBm across the temperature range from $-30^{\circ}C$ to $+85^{\circ}C$.

• 한국대기환경학회지
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• 제9권1호
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• pp.44-50
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• 1993

The suspended particulate matters had been collected by a cascade impactor having 9 size fragnated stages for 2 years (Dec. 1989 to Nov. 1991) in Kyung Hee University-Suwon Campus. The particulate matters were then collected on each stage by membrane filters. The weight concentration on each stage was estimated by a microbalance and further chemical element concentrations were determined by an XRF system. The study focused on developing of a receptor model using the TTFA (target transformation factor analysis) to apportion aerosol mass with the 30 ambient data sets. Each data set consists of the 8 size-ranged subdata sets characterized by 13 element variables. Even though a couple of sources could not be identified, three to five sources were extracted from each aerosol size-range, and then 9 statistical source profiles were generated. Finally, source contribution of particulate matters on each size-range could be estimated in Suwon area.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.338-345
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• 2000

In this study, applicability of PMT in domestic area and test procedure were studied. At six test holes of three construction sites in Pusan, PMT using Elastometer-200 type was done. The problems during test were investigated and the test results were analysed. Limit pressure, p$\sub$ι/ could be determined by p- Δv/v method. Using PMT results, marine soil in Pusan could be classified approximately. Net limit pressure value was in the range of 6.4 ∼ 22.5 kg/$\textrm{cm}^2$ in clay, 2.2 ∼ 30.0 kg/$\textrm{cm}^2$ in sand, 13.0 ∼ 58.0 kg/$\textrm{cm}^2$ in weathered soil and 47.0 ∼ 190.0 kg/$\textrm{cm}^2$ in weathered rock. Also, E$\sub$m//p$\sub$ι/ value was in the range of 2.4 ∼ 7.0 in clay, 2.6 ∼ 12.1 in sand, 6.8 ∼ 17.1 in weathered soil and 7.2 ∼ 29.6 in weathered rock.