• Journal of Astronomy and Space Sciences
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• 제24권4호
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• pp.315-326
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• 2007

최근에 제안된, 이웃하는 타원 궤도의 상대운동에 대한 몇 가지 양함수형 해를 분석하였다. 이 해를 이용한 상대운동 결과를 일반 선형화 운동 방정식의 해석적 해와 비교했다. 수치계산 결과를 위한 초기 조건은 Hill-Clohessy-Wiltshire(HCW) 운동방정식에 의한 해의 역함수로 구했다. 기준 궤도의 차이에도 불구하고 상대적으로 작은 이심률의 궤도 일 경우에는 타원 상대운동 궤도와 원 상대운동 궤도의 결과는 근접했다. 주위성의 궤도가 상대적으로 큰 이심률을 가질 경우에는, 기본 궤도로 원 궤도를 이용하는 HCW 운동방정식은 다른 타원 상대운동 궤도 방정식의 해보다 상대적으로 큰 오차를 갖는다.

• 한국임상약학회지
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• 제21권2호
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• pp.145-155
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• 2011

The objective of this study was to determine whether any pretreatment parameters were associated with pharmacological effect or toxicity parameters after vincristine administration and to describe a mathematical model, which explains the interpatient pharmacodynamic variability. The relationship between patient characteristics and vincristine dose and hematological toxicity were evaluated. 68 pediatric and adolescence patients and 107 adults with acute lymphoblastic leukemia were treated with vincristine $1.5mg/m^2/day$ IV and other anticancer drugs as scheduled. Complete blood counts and other blood test results were obtained. The input variables were age, gender, weight, lean body weight (LBW), height, body surface area, vincristine dose and total vincristine dose. The outcome measures were nadir values (white blood cells, absolute neutrophil counts, hemoglobin, and platelets); the absolute decrease, relative decrease, and survival fraction of blood cells. Polynomial regression analysis was carried out to determine the other significant covariates. The variability of $WBC_{nadir}$ was modeled with good precision and accuracy with a two-covariate model. This model should be validated and improved on with further clinical data. We believe that such pharmacodynamic modeling should be explored further to determine its performance and clinical relevance compared with modeling using pharmacokinetic parameter.

• 한국전자통신학회논문지
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• 제14권6호
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• pp.1069-1076
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• 2019

정보통신기술의 발달로 군의 무기체계가 네트워크로 연결되어 실시간으로 데이터를 주고받아 작전을 수행하는 네트워크 중심전으로 전장 환경이 크게 변하고 있는 추세이다. 네트워크 중심전의 핵심 시스템은 전술데이터 링크이며, 전술데이터링크 가입자는 유선, 무선, 위성 네트워크를 통해 실시간으로 전술정보를 주고받아 전장상황을 공유한다. 시간이 지날수록 전술데이터링크 시스템을 탑재한 군의 무기체계가 증가하고, 통신장비의 성능이 개선되는 상황에서 전술데이터링크를 통해 주고받는 데이터의 양도 증가할 수밖에 없다. 본 연구에서는 전술데이터링크의 데이터를 처리하는 데이터링크 처리기의 전술자료 송신 메커니즘을 개선하여 전술데이터링크 시스템의 전송속도 및 처리 용량을 향상시킬 수 있는 방법을 제안한다.

• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.589-593
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• 2014

AlNO multi-layer thin films on aluminum substrates were prepared by DC reactive magnetron sputtering method. $Al_2O_3$/AlNO(LMVF)/AlNO(HMVF)/Al/substrate of 4 multi-layer has been prepared in an Ar and ($N_2+O_2$) gas mixture, and $Al_2O_3$ of top layer is anti-reflection layer on double AlNO(LMVF)/AlNO(HMVF) layers and Al metal of infrared reflection layer. In this study, the roughness and surface properties of AlNO thin films were estimated by field emission scanning electron microscopy(FE-SEM). The grain size of AlNO thin films increased with increasing sputtering power. The composition of thin films has been systematically investigated using electron probe microanalysis(EPMA). The optical properties with wavelength spectrum were recorded by UV-Vis-NIR spectrophotometry at a range of 200~1,500 nm. The absorptance of AlNO films shows the increasing trend with swelling ($N_2+O_2$) gas mixture in HMVF and LMVF deposition. The excellent optical performance showed above 98% of absorptance in visible wavelength region.

• 한국산학기술학회논문지
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• 제20권11호
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• pp.217-223
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• 2019

복합 형상 부품 제작 및 제작 공정의 일체화 장점으로 3D 프린팅 기술의 적용 분야가 확대되고 있으며, 지속적인 연구 개발에 의해 다양한 기술방안들이 등장하고 있다. 대표적인 기술로는 파우더 형태의 소재 위에 레이저를 조사함으로써 원하는 영역을 소결 및 적층 제작하는 방식의 SLS 기술이 있으며, 고성능의 엔지니어링 플라스틱을 활용하여 실제 사용할 수 있는 부품을 제작하는 사례가 늘어나고 있다. 본 연구에서는 활용도가 높은 고분자 소재인 폴리아미드 12 소재 및 글라스 비드가 보강된 폴리아미드 12 소재를 대상으로 인장시편을 제작하여 시편 제작 방향 및 인장 시험 온도에 따른 특성 결과를 비교 분석하였다. 시편 제작방향은 작업 평면 기준으로 0°, 45°, 90° 로 구분하였으며, 인장시험온도는 -25℃, 25℃, 60℃로 조건을 구분하였다. 시험 결과로부터 제작 방향이 90°에 가까울수록 두 소재 모두 탄성률의 미세한 감소를 보였으며, 인장강도는 PA12보다 글라스 비드 보강 PA12가 제작방향에 대한 의존성을 명확하게 보였다. 또한 시험 온도 증가에 따라 탄성률 및 인장강도의 저하를 확인할 수 있었다.

• 정보과학회 논문지
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• 제41권12호
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• pp.1081-1089
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• 2014

문맥의존 철자오류의 교정 방법은 크게 규칙을 이용한 방법과 통계 정보에 기반을 둔 방법으로 나뉘며, 이중 통계적 오류 교정 방법을 중심으로 연구가 진행되었다. 통계적 오류 방법은 문맥의존 철자오류 문제를 어의 중의성 해소 문제로 간주한 방법으로서, 교정 대상 어휘와 대치 후보 어휘로 이루어진 교정 어휘 쌍을 문맥에 따라 분류하는 방법이다. 본 논문에서는 본 연구진의 기존 연구 결과인 교정 어휘 쌍을 이용한 확률 모델의 성능 향상을 위해 어절 n-gram 모델을 기존 모델에 결합하는 방법을 제안한다. 본 논문에서 제안하는 결합 모델은 각 모델을 통해 계산된 문장의 확률을 보간(interpolation)하는 방법과 각각의 모델을 차례대로 적용하는 방법이다. 본 논문에서 제안한 두 가지 결합 모델 모두 기존 모델이나 어절 n-gram만 이용한 모델보다 높은 정확도와 재현율을 보인다.

• 한국전기전자재료학회논문지
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• 제25권2호
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• pp.100-104
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• 2012

Fin-type SONOS (silicon-oxide-nitride-oxide-silicon) flash memory has emerged as novel devices having superior controls over short channel effects(SCE) than the conventional SONOS flash memory devices. However despite these advantages, these also exhibit undesirable characteristics such as corner effect. Usually, the corner effect deteriorates the performance by increasing the leakage current. In this paper, the corner effect of fin-type SONOS flash memory devices is investigate by 3D Process and device simulation and their electrical characteristics are compared to conventional SONOS devices. The corner effect has been observed in fin-type SONOS device. The reason why the memory characteristic in fin-type SONOS flash memory device is not improved, might be due to existing undesirable effect such as corner effect as well as the mutual interference of electric field in the fin-type structure as reported previously.

• 한국도로학회논문집
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• 제18권4호
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• pp.29-35
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• 2016

PURPOSES : The new waste management policy of South Korea encourages the recycling of waste materials. One material being recycled currently is tire-derived fuel (TDF) ash. TDF is composed of shredded scrap tires and is used as fuel in power plants and industrials plants, resulting in TDF ash, which has a chemical composition similar to that of the fly ash produced from coal. The purpose of this study was to evaluate the properties of an asphalt concrete mix that used TDF ash as the mineral filler. METHODS : The properties of the asphalt concrete were evaluated for different mineral filler types and contents using various measurement techniques. The fundamental physical properties of the asphalt concrete specimens such as their gradation and antistripping characteristics were measured in accordance with the KS F 3501 standard. The Marshall stability test was performed to measure the maximum load that could be supported by the specimens. The wheel tracking test was used to evaluate the rutting resistance. To investigate the moisture susceptibility of the specimens, dynamic immersion and tensile strength ratio (TSR) measurements were performed. RESULTS : The test results showed that the asphalt concrete containing TDF ash satisfied all the criteria listed in the Guide for Production and Construction of Asphalt Mixtures (Ministry of Land, Infrastructure and Transport, South Korea). In addition, TDF ash exhibited better performance than that of portland cement. The Marshall stability of the asphalt concrete with TDF ash was higher than 7500 N. Further, its dynamic stability was also higher than that listed in the guide. The results of the dynamic water immersion and the TSR showed that TDF ash shows better moisture resistance than does portland cement. CONCLUSIONS : TDF ash can be effectively recycled by being used as a mineral filler in asphalt, as it exhibits desirable physical properties. The optimal TDF ash content in asphalt concrete based on this study was determined to be 5%. In future works, the research team will compare the characteristics of asphalt concrete as function of the mineral filler types.

• Journal of Advanced Marine Engineering and Technology
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• 제39권2호
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• pp.179-186
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• 2015

In the indoor location estimation system, which has recently been actively studied, the received signal strength indicator contains a high level of noise when measuring the signal strength in the range between two nodes consisting of a receiver and a transceiver. To minimize the noise level, this paper proposes an improved adaptive smoothing filter that provides different exponential weights to the current value and previous averaged one of the data that were obtained from the nodes, because the characteristic signal attenuation of the received signal strength indicator generally has a log distribution. The proposed method can effectively decrease the noise level by using a feedback filter that can provide different weights according to the noise level of the obtained data and thus increase the accuracy in the distance and location without an additional filter such as the link quality indicator, which can verify the communication quality state to decrease the range errors in the indoor location recognition using ZigBee based on IEEE 802.15.4. For verifying the performance of the proposed improved adaptive smoothing filter, actual experiments are conducted in three indoor locations of different spatial sections. From the experimental results, it is verified that the proposed technique is superior to other techniques in range measurement.

• Journal of Biosystems Engineering
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• 제33권3호
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• pp.204-209
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• 2008

The power strength of electric wave of reader looked radiation forms from the gate type RFID system. The more distant from antennas, the weaker of power strength of electric wave. The power strength of electric wave with 3 antennas showed stronger than its with 2 antennas. With 2 antennas, the coefficient of correlation between the power strength of electric wave and response ability of tag was 0.665 (p=0.009), and it showed results at significance level. With 3 antennas, the coefficient of correlation was 0.711 (p=0.004), correlationship between the power strength of electric wave and the response ability of tag showed at significance high level. From the analysis result about tag reading performance on the gate type RFID system, the reading rate was good when tags were attached on a acrylic plate which were located in front of 3 or 4 antennas. As tags were getting away from antennas, the reading rate was decreased. The nearer from antennas, the higher the reading rate at the center. When tags were turned at right angles with antennas, the longer distant from antennas, the lower reading rates at the center, right and left locations. When the number of antennas and distance are constant, respectively, the significant difference of the tag reading rates according to the locations of left, right and center were not found.