• 방송공학회논문지
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• 제16권1호
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• pp.123-132
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• 2011

분산 비디오 부호화(Distributed Video Coding: DVC)는 계산 성능 및 전력이 제한된 환경에 적합한 초경량 비디오 부호화 기법으로 주목 받고 있으며, 부호화 성능을 개선하기 위한 많은 연구가 진행되고 있다. 본 논문에서는 DVC의 부호화 성능 개선을 위한 율-왜곡(Rate-Distortion) 기반의 영역별 선택적 블록 부호화 기법을 제안한다. 제안 기법은 복호기에서 보조정보를 얻는 과정에서 얻어지는 움직임 벡터가 부호기로 피드백 되는 경우, 이를 이용하여 움직임 보상 예측 신호를 구하고 율-왜곡 기반으로 블록 단위로 선택적 블록 부호화를 수행한다. 모의실험을 통하여 본 논문에서 제안한 움직임 정보 피드백을 이용한 율-왜곡 기반의 선택적 블록 부호화 기법이 기존의 DVC 부호화 기법에 비해 시퀀스에 따라 최대 약 2.2 dB의 PSNR 성능 향상을 확인하였다. 또한 율-왜곡을 고려하여 일부 영역만 부호화함으로써 기존 방식에 비해 부호화 복잡도를 줄일 수 있음을 보인다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1137-1140
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• 2014

선박의 전동기에 고장이 발생하면 대개 육상에서 수리 후 본선에 다시 재설치 되고 있으나 연결 단자의 기호 표시가 지워지거나 분명치 않을 때는 결선과정에서 전동기 권선의 극성 구별이 어려워진다. 이로 인해 Y-${\delta}$ 기동의 전동기에서 한 권선의 극성을 반대로 잘못 연결하는 경우 전원 투입과 동시에 과다한 전류가 흐르면서 재차 2차 고장으로 이어질 위험이 있다. 이러한 문제와 관련하여 본 논문은 고정자의 1상 권선에 미소 직류전류를 흘릴 때 나머지 권선들에서 유도되는 과도 기전력의 특성을 토대로 아날로그 멀티테스터를 이용한 고정자 권선의 극성 판별법을 제시하고 관련 특성을 분석한다. 또한, 이 같은 방식을 실제 전동기에 적용하여 단계적인 측정과정을 통해 단자연결의 이상여부를 현장에서 용이하게 판별할 수 있는지를 확인해 보기로 한다.

• 한국산업정보학회논문지
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• 제17권2호
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• pp.19-27
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• 2012

In railway tunnel environment, the reliability of a high-data-rate and real-time train-to-wayside communication should be maintained especially when high-speed train moves along the track. In China and Europe, the communication frequency around 900 MHz is widely used for railway applications. At this carrier frequency band, both of the solutions based on continuously laid leaky coaxial cable (LCX) and discretely installed base-station antennas (BSAs), are applied in tunnel radio coverage. Many available works have concentrated on the radio-wave propagation in tunnels by different kinds of prediction models. Most of them solve this problem as natural propagation in a relatively large hollow waveguide, by neglecting the transmitting/receiving (Tx/Rx) components. However, within such confined areas like railway tunnels especially loaded with train, the complex communication environment becomes an important factor that would affect the quality of the signal transmission. This paper will apply a full-wave numerical method to this case, for considering the BSA or LCX, train antennas and their interacted environments, such as the locomotive body, overhead line for power supply, locomotive pantograph, steel rails, ballastless track, tunnel walls, etc.. Involving finite-difference time-domain (FDTD) method and uni-axial anisotropic perfectly matched layer (UPML) technique, the entire wireless RF downlinks of BSA and LCX to tunnel space to train antenna are precisely modeled (so-called integrative modeling technique, IMT). When exciting the BSA and LCX separately, the field distributions of some cross-sections in a rectangular tunnel are presented. It can be found that the influence of the locomotive body and other tunnel environments is very significant. The field coverage on the locomotive roof plane where the train antennas mounted, seems more homogenous when the side-laying position of the BSA or LCX is much higher. Also, much smoother field coverage solution is achieved by choosing LCX for its characteristic of more homogenous electromagnetic wave radiation.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1675-1682
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• 2012

Aim: The study aim was to determine the frequency with which women decline clinicians' treatment recommendations and variations in this frequency by age, cancer and service descriptors. Design: The study included 36,775 women diagnosed with early invasive breast cancer in 1998-2005 and attending Australian and New Zealand breast surgeons. Rate ratios for declining treatment were examined by descriptor, using bilateral and multiple logistic regression analyses. Proportional hazards regression was used in exploratory analyses of associations with breast cancer death. Results: 3.4% of women declined a recommended treatment of some type, ranging from 2.6% for women under 40 years to 5.8% for those aged 80 years or more, and with parallel increases by age presenting for declining radiotherapy (p<0.001) and axillary surgery (p=0.006). Multiple regression confirmed that common predictors of declining various treatments included low surgeon case load, treatment outside major city centres, and older age. Histological features suggesting a favourable prognosis were often predictive of declining various treatments, although reverse findings also applied with women with positive nodal status being more likely to decline a mastectomy and those with larger tumours more likely to decline chemotherapy. While survival analyses lacked statistical power due to small numbers, higher risks of breast cancer death were suggested, after adjusting for age and conventional clinical risk factors, (1) for women not receiving breast surgery for unstated reasons (RR=2.29; p<0.001); and (2) although not approaching statistical significance $p{\geq}0.200$), for women declining radiotherapy (RR=1.22), a systemic therapy (RR1.11), and more specifically, chemotherapy (RR=1.41). Conclusions: Women have the right to choose their treatments but reasons for declining recommendations require further study to ensure that choices are well informed and clinical outcomes are optimized.

• 한국컴퓨터정보학회논문지
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• 제16권2호
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• pp.101-111
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• 2011

본 논문에서는 밀집된 무선센서네트워크에서 노드의 밀집도를 고려하고 에너지 효율적으로 동작하는 클러스터 기반의 새로운 MAC 프로토콜을 제안한다. 제안한 프로토콜은 인접노드의 밀집도가 높으면 발생하는 에너지 낭비 요인들을 줄이기 위해 클러스터 헤더가 인접 노드의 밀집도를 고려하도록 디자인 되었다. 클러스터 헤더가 인접노드의 밀집도를 파악하고 밀집도가 높을 경우 2개 이상의 티어로 분리하여 동작하도록 ACK 메시지를 수정하였다. 그리하여 같은 티어에 있는 노드들간의 통신을 하도록 구현하여 에너지 낭비요소를 줄이고 네트워크의 수명을 연장하였다. 본 논문에서는 NS-2 네트워크 시뮬레이터를 사용하여 기존의 MAC 프로토콜인 S-MAC과 비교하였으며, 패킷전송률, 처리량, 에너지 소모 부분에서 S-MAC보다 우수함을 보였다.

• Nuclear Engineering and Technology
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• 제38권6호
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• pp.585-590
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• 2006

This paper describes the results of an irradiation test and the specifications of the pneumatic transfer system (PTS) in the NAA #3 irradiation hole at the HANARO research reactor, which was reinstalled after some modifications of the operation mode at the end of 2004. The outer and inner diameters of the PE transfer tube are 34.1 and 27.5 mm, respectively. PE rabbit was used for sample irradiation. The $N_2$ gas pressure of the PTS lines was adjusted to 0.75 bar. The average sending time to the reactor was $8.5{\pm}0.3$ s and the average receiving time back to the receiver was $3.2{\pm}0.2$ s. The internal and external temperature of the irradiation tube was measured in a range of 50 to $80^{\circ}C$ for a 40 s to 80 s irradiation time, respectively. The optimum irradiation time was estimated to be less than 80 s. The thermal, epithermal and fast neutron flux at 30 MW thermal power were $1.42{\pm}0.01{\times}10^{14},\;1.51{\pm}0.04{\times}10^{13}$ and $9.48{\pm}0.69{\times}10^{11} n{\cdot}cm^{-2}{\codt}s^{1-}$, respectively. The cadmium ratio was approximately 9.40. The data obtained will be applied to supplement user information and for reactor management.

• 한국치위생학회지
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• 제15권4호
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• pp.743-750
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• 2015

Objectives: The purpose of the study is to examine the correlation and influencing factors among ethics position, self-esteem, and perception of patient medical information protection in the dental hygiene students. Methods: This is a cross sectional study using the structured questionnaire. A self-reported questionnaire was completed by 202 dental hygiene students using the stratified sampling method from September 1 to November 1, 2013. The questionnaire was modified and complemented from Ethics Position Questionnaire (EPQ). The questionnaire included EPQ, self-esteem, and perception of patient medical information protection. Data were analyzed by independent t-test, one way ANOVA, Duncan's multiple comparison analysis, Pearson's correlation analysis, and stepwise multiple regression analysis using IBM SPSS Statistics 21.0 program. Results: There was a positive correlation among all the variable including idealism position, self-esteem, and perception of patient medical information protection, The factors influencing on the perception of patient medical information protection were idealism position (${\beta}=0.271$, p<0.001) and self-esteem (${\beta}=0.248$, p<0.001). The corrected explanation power of the model was 15.1%. Conclusions: As the idealism position and self-esteem become higher, the perception of patient medical information protection gets higher. Therefore, this study suggests that it is needed to develop and vitalize implement the appropriate programs enhancing ethics consciousness, proper position, and self-esteem in the dental hygiene students receiving the education for their professionalism in the dental hygiene curricula.

• 농촌계획
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• 제11권2호
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• pp.51-57
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• 2005

It has been well known that soil erosion and sediments from alpine agricultural fields are causing severe water quality and turbidity problems in receiving waters. Also these result in the loss of money because farmers have to buy top soils to provide enough root zone in the following year. Thus, there have been needs to reduce soil erosion and sediment discharge into the stream networks. To accomplish this end, an effective erosion control plans should be developed based on scientific research, not by rule of thumb. The Universal Soil Loss Equation (USLE) has been widely used to estimate the soil erosion in many countries over the years. In this study, the USLE was used to estimate soil erosion potential under different cropping scenarios in HongCheon County, Kangwon. The soil erosion potential for continuous corn cropping was the highest compared with those from continuous potato find average cropping scenarios. This indicates the soil erosion plans need to be established considering cropping system in the field. The Unit Stream Power Erosion-Deposition (USPED) was applied for HongCheon County to estimate soil erosion and deposition areas. The USPED estimated results can be used to complement USLE results in developing effective erosion control plans.

• 지역연구
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• 제14권1호
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• pp.91-107
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• 1998

Waste disposal problem is one of the most important social welfare indicators in urban area, because the volume of waste generated from urban area is remarkable. So far most waste of Seoul has been disposed at landfills. However, this landifill disposal method is confronted with several difficulties in recent. As public concern on environmental problem increases and autonomy system is settled down, local community people of the landfills refuse to receive the waste produced other places any more. It brought reginal confliction problem between waste sending and receiving by refusing to accept waste from certain region. Furthermore, it is difficult to find another place to fill up the waste, while the existing landfiis is reached at the limit in the near future. In terms of environmental aspects landfill method is not the best way to dispose waste. It contaminates the soil and ground/underground water by leaking water containing many serious pollutants as well as offensive oder. In terms of equity, this waste disposal method is not fair. Environmental pollution causes damage to residence near to the landfills, while the waste produced other places. In order to satisfy the equity aspect, the waste generated a region should be disposed within the region. Incineration of Waste has been provided as the alternative. Government plans to construct waste incinerator in every anatomy, so the waste produced by local community is disposed within their local autonomous area. However, the location decision is not easy, since waste incinerator is one of the facilities to the community people. We can not apply the existing location models for this problem, because they show strong NIMBY phenomenon for the location. The location of waste incinerator should be determined very carefully with consideration of various location factors and criteria. This study proposes a methodology for determining the location of the waste incinerators by utilizing GIS, which is a power research tool for location decision where various geographical factors related. We drive the location factors which should be considered in the determination of waste incinerators. They involve environmental, socio-economic, and institutional factors. In first, we eliminate the area which is located within the environmental location criteria such as slope, fault line, distance to river, and then eliminate ares which is conflict with the social and institutional criteria.

• 한국통신학회논문지
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• 제29권2A호
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• pp.174-180
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• 2004

2000년에 개최된 세계전파통신회의(WRC)에서 1지역(유럽, 아랍 및 아프리카 지역) 및 3지역(아시아 및 오세아니아 지역)의 방송위성계획이 개정됨에 따라, 국제전기통신연합(ITU)에서는 방송위성계획과 관련된 전파규칙의 규제 절차와 공유 기준을 검토하기로 하였다. 따라서 본 연구에서는 우리나라의 방송위성망을 중심으로 위성방송 수신안테나 크기와 편파에 따른 방송위성망의 주파수(11/12GHz대역) 및 제도 공유 문제를 분석하였다. 분석 결과 향후 우리나라에서 동경113$^{\circ}$에 방송위성을 추가로 운용하게 되면 현재 운용중인 116$^{\circ}$의 위성방송에 심각한 간섭을 줄 수 있음을 알 수 있었다. 그러나 방송위성계획을 토대로 위성 간격을 6$^{\circ}$간격으로 유지할 경우 작은 안테나 (45cm) 사용에 의한 간섭은 크게 문제가 되지 않는다는 것을 알 수 있었다.