목 적: 3D TV에서 2D 및 3D 영상 시청 전, 후 피로도와 시기능 변화를 피로도 설문지(Simulator Sickness Questionnaire)와 시기능 검사를 통해 비교 분석하였다. 방 법: 시기능의 이상이 없고 3D 입체영상 시청이 가능하며 양안 교정시력 0.8 이상인 23-29세(평균 연 령 25.3±1.6세)의 15명을 대상으로 하였다. 47인치 3D TV를 이용하여 2.5m 거리에서 30분 길이의 2D 및 3D 영화를 시청하였다. 시청 전, 후 피로도(5가지 범주, 28가지 항목의 설문) 및 시기능(원거리 및 근거리 사위, 폭주 근점, 상대조절력 등)을 검사하여 분석하였다. 결 과: 2D 및 3D 영상 시청 전, 후에 피로도 검사에서 2D 영상에서는 흐려 보임(p=0.019), 건조함 (p=0.023), 피로함(p=0.003)이 영상 시청 후 통계적으로 유의하게 증가하였고 3D영상에서는 피로함 (p=0.019), 어지러움(p=0.047)이 영상 시청 후 통계적으로 유의하게 증가하는 결과를 보였다. 총 28개의 항 목 중에 2D에서 3개 항목, 3D에서 2개 항목에서만 차이가 있었고, 그 점수 변화는 크지 않았다. 또한 시기 능 검사에서는 모든 항목에서 유의한 변화가 나타나지 않았다. 결 론: 2D 및 3D 영상 시청 전, 후에 피로감은 동일하게 측정되었다. 이는 3D 영상 전후 피로도가 증가했 다는 이전의 보고와 다른 결과이다. 이는 본 실험과 이전 보고들의 3D 시청 환경(3D 컨텐츠, 시청 거리, 3D 영상 표시 장치 등)이 다르기 때문으로 생각된다. 이는 또한 3D TV 시청 시 특정 조건에서는 피로감이 2D에 비교하여 심각하지 않을 수 있다는 것을 의미한다.

Densification behavior of nano-agglomerate powder during pressureless sintering of Fe-Ni nanopowder was investigated in terms of diffusion kinetics and microstructural development. To understand the role of agglomerate boundary for sintering process, densification kinetics of Fe-Ni nano-agglomerate powder with different agglomerate size was investigated. It was found that activation energy for densification was lower in the small-sized agglomerate powder. The increase in the volume fraction of inter-agglomerate boundary acting as high diffusion path might be responsible for the enhanced diffusion process.

We report on the formation and chemical leaching of non-equilibrium alloy produced by rod milling. X-ray diffractometry, transmission electron microscopy, differential scanning calorimetry, scanning electron microscopy, and vibrating sample magnetometry were used to characterize the as-milled and leached specimens. After 400 h, only the peak of the body-centered cubic type was present in the XRD pattern. The entire rod milling process could be divided into three different stages of milling: agglomeration, disintegration, and homogenization. The saturation magnetization, decreased with increased milling time, the of the powders before milling was about 113.8 emu/g, the after milling for 400 h was about 11.55 emu/g. Leaching of the Al in KOH of the Al at room temperature from the as-milled powders did not induce any significant change in the diffraction pattern. After the leached specimen had been annealed at for 1 hour, the nanoscale crystalline phases were transformed into the bcc Fe, cubic Co, and phases. On cooling the specimen from 85, the degree of magnetization increased slightly, then increased sharply at approximately 364.8, indicating that the bcc phase had been transformed to the Fe and Co phases.

We conducted a deep CCD observations in V band to obtain stellar density distribution and to determine the distances toward two molecular clouds with anomalous velocity in the Galactic anti-center region. Star count method based on the linear programming technique was applied to the CCD photometric data. We found two prominent peaks at distances of around 1.4 and 2.7 kpc. It is found that the first peak coincides well with stellar density enhancement of B8-A0 stars and the second one with the outer Perseus arm. The effect of the choice of the luminosity function is discussed. The stellar number density distribution is used to derive the distances to the molecular clouds and the visual extinctions caused by the clouds. We found that two molecular clouds are located almost at the same distance of about 1.1 ± 0.1 kpc, and the peak extinctions caused by the clouds are about 2.2 ± 0.3 mag in V band.

We present a code which identifies individual clouds in crowded region using IMFORT interface within Image Reduction and Analysis Facility (IRAF). We define a cloud as an object composed of all pixels in longitude, latitude, and velocity that are simply connected and that lie above some threshold temperature. The code searches the whole pixels of the data cube in efficient way to isolate individual clouds. Along with identification of clouds it is designed to estimate their mean values of longitudes, latitudes, and velocities. In addition, a function of generating individual images (or cube data) of identified clouds is added up. We also present identified individual clouds using a 12CO survey data cube of Galactic Anticenter Region (Lee et al. 1997) as a test example. We used a threshold temperature of 5σ 5σ rms noise level of the data With a higher threshold temperature, we isolated subclouds of a huge cloud identified originally. As the most important parameter to identify clouds is the threshold value, its effect to the size and velocity dispersion is discussed rigorously.

A long-term wind resource map was made to provide the key design data for the 2.5 GW Korean West-South Offshore Wind Project, and its reliability was validated. A one-way dynamic downscaling of the MERRA reanalysis meteorological data of the Yeongwang-Gochang offshore was carried out using WindSim, a Computational Fluid Dynamics based wind resource mapping software, to establish a 33-year time series wind resource map of 100 m x 100 m spatial resolution and 1-hour interval temporal resolution from 1979 to 2012. The simulated wind resource map was validated by comparison with wind measurement data from the HeMOSU offshore meteorological tower, the Wangdeungdo Island meteorological tower, and the Gochang transmission tower on the nearby coastline, and the uncertainty due to long-term variability was analyzed. The long-term variability of the wind power was investigated in inter-annual, monthly, and daily units while the short-term variability was examined as the pattern of the coefficient of variation in hourly units. The results showed that the inter-annual variability had a maximum wind index variance of 22.3% while the short-term variability, i.e., the annual standard deviation of the hourly average wind power, was 0.041±0.001, indicating steady variability.