유한요소해석을 통하여，지중 매설된 GFRP 관로의 거동과 좌굴안정성을 분석하였 다. GFRP 관로에 토압과 차량하 중과 같은 외압만이 작용하는 경우와，외압과 함께 수압이 내압으로 작용하는 경우에 대해 해 석을 수행하였으며，해석 대상 관로는 현재 생산되는 GFRP 관로로 한정 하고，응력과 변위，좌굴강도를 검토하였다. 또한，관로 연결 플 랜지 의 웅력집중 현상을 저감하기 위하여 형상을 개 선시 킨 플 랜지 에 대해 해석을 수챙하였다. 연결부 목 부위의 최대 웅력을 검토하기 위한 캔틸레버 모델과，지중 매설시의 모델 두 가지 에 대해 해석을 수행하여 웅력을 검토하였다. 해석 결과 지중 매설된 GFRP 관로에 외압이 작용하는 경우와 좌굴에 대해서는 안전하였으며，개선된 플랜지의 웅력 집중도 상당히 저감되었음을 확인 할 수 있었다.

Preliminary time-series observations for short-period variability survey (SPVS) were carried out using a 155mm refractor and a 2k×3k CCD camera at Bohyunsan Optical Astronomy Observatory. We found 21 new variable stars in the 90′×60′ test field region : 9 eclipsing binary stars, 5δ Scuti type stars, a γ Doradus type star, and 6 long period variables. The observing field center is R.A. 05 h00m00s, DEC. 50∘00′00" (J2000.0). The period and amplitude ranges for the short-period variables, i.e., δ Scuti stars, were 0.052day - 0.107day and 0.012mag - 0.064mag, respectively.

Time-series observations were carried out using a 155mm refractor and a 2k×3k CCD camera at Bohyunsan Optical Astronomy Observatory. We found 38 new variable stars in the 2.3°×2.4° region around the Cepheid variable TU Cas: 22 eclipsing binary stars, 11 δ Scuti type stars and an RR Lyrae star, and 4 unclassified variables.

We have been performing a wide-field photometric monitoring program, named SPVS (Short-Period Variability Survey), at the Bohyunsan Optical Astronomy Observatory (BOAO). The observation system consists of a small refracting telescope (D = 155 mm, f = 1050 mm) and a 2k×3k CCD Camera. The field of view is 1.0°×1.5°. Detection limit is about V = 13 for short-period small amplitude variables such as δ Scuti-type pulsating stars, and about V = 15 for long-period large amplitude variables such as eclipsing binaries and RR Lyrae stars. The instrument is designed to be remote-controlled through internet. The primary purpose of this project is to search for variable objects in bright Galactic open clusters. We present results of test observations conducted towards NGC 7092.

Observation environment of the Bohyunsan Optical Astronomy Observatory(BOAO) has been examined using various statistical data including real observation times versus allocated times and seeing statistics. The data have been collected from the observation logs of the 1.8m telescope in the period 1998 - 2004. New criteria have been set up to calculate a more realistic observation efficiency of the observatory. The new statistical analysis based on the new criteria gives the overall observation efficiency of BOAO as 38.6%, that is equivalent to 115.8 observable nights out of 300 allocatable nights. The seeing statistics shows that the mean seeing measured at the focal images is 2".3. The present study of the observation environment of BOAO suggests that differential photometry and spectroscopy should be preferred modes of observation to maximize the productivity of BOAO.

Through time-series CCD photometry using a 130mm refractor of Busan Science Academy, we found a new δ Scuti type variable star, esc 03665-00576. We performed following observations using a 1.8m telescope of Bohyunsan Optical Astronomy Observatory. Three frequencies have been derived by multiple-frequency analysis, which are 10.968, 7.156 and 15.182cycle day−1, respectively. V-amplitude of esc 03665-00576 is ΔV= 0.04.

Through time-series CCD photometry using a 155mm refractor, we found a new δ Scuti type variable star, HD 235428, near a known bright δ Scuti type star, DQ Cep. We performed follow-up observations using a 61cm telescope at Sobaeksan Optical Astronomy Observatory. Four frequencies have been derived by multiple-frequency analysis, which are 15.804, 5.498, 15.351 and 24.516cycle day−1 , respectively. V-amplitude of HD 235428 is ΔV = 0.026.

The characteristics of the BOES (Bohyunsan Observatory Echelle Spectrograph) CCD camera is presented. In order to get optimum gain and readout noise of the CCD, we examine the variation of the gain and readout noise by changing the value of output drain voltage of the CCD and measuring the gain using transfer curve, which is defined as the plot of variance versus mean exposure level of a homogeneous light onto the CCD surface. The gain and readout noises are optimised to be 0.5e −/ADU and 3e−, which is good for highest signal-to-noise ratio and contrast for the low light level characteristics of the BOES. We also measure the dark count of the CCD by getting five dark images with 3600 seconds exposure time. The mean dark count from median stacked dark images is essentially zero. A table of positions of defected pixels is also presented.

The objective of the study is to suggest planning directions for practical use and to find the conditions of tourist attractions in rural villages founded on city-dweller's preference. Both a questionnaire and a field survey were used for the study. Selected were four villages such as Oryan-ri, gachun-ri, Junggi-ri, and Gyochon-ri. The results of the study are as follows: City-dweller's valued on natural environment resources in rural tourism and felt uncomfortable to accommodations. The scoring system reflecting functions of six resources showed that common problems encountered in rural tourism were lacks of people's organization, and human exchange mind, and tourism-related leasure places and facilities. Based upon the results, some measures to develop villages were suggested.

Shortening the lasing wavelength(particularly below infrared ; the visible region) of laser diodes is very attractive because it can provide a wide range of applications in the fields of optical information, measurement, sensor, the development of medical instrument, and optical communication through plastic fibers. According to the recent researches on the field, InGaAsP/GaAs was suggested as a material for red-light laser. In this study, in order to grow InGaAsP/GaAs epitaxial layer on InGaAsP/GaAs by LPE, we used GaP and InP two phase solution technique for 670nm and 780 nm region, respectively. Through the X-ray diffraction measurement for the epitaxial layer grown from the experiments, we found that the lattice mismatch of In0.46Ga0.54As0.07P0.93/GaAs and In0.19Ga0.81As0.62P0.38/GaAs was about +0.3% and +0.1%, respectively.