• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.1D
• /
• pp.81-88
• /
• 2012

This present research was carried out by dividing two parts; field surveying and data processing, in order to analyze changed patterns of a shoreline. Firstly, the shoreline information measured by the precise GPS positioning during long duration was collected. Secondly, the algorithm for detecting an auto boundary with regards to the changed shoreline with multi-image data was developed. Then, a comparative research was conducted. Haeundae beach which is one of the most famous ones in Korea was selected as a test site. RTK-GPS surveying had been performed overall eight times from September 2005 to September 2009. The filed test by aerial Lidar was conducted twice on December 2006 and March 2009 respectively. As a result estimated from both sensors, there is a slight difference. The average length of shoreline analyzed by RTK-GPS is approximately 1,364.6 m, while one from aerial Lidar is about 1,402.5 m. In this investigation, the specific algorithm for detecting the shoreline detection was developed by Visual C++ MFC (Microsoft Foundation Class). The analysis result estimated by aerial photo and satellite image was 1,391.0 m. The level of reliability was 98.1% for auto boundary detection when it compared with real surveying data.

• Progress in Medical Physics
• /
• v.8 no.1
• /
• pp.53-67
• /
• 1997

General hospitals have being under the influence of various and specific environment of electromagnetic field. The factors are development of medical electric equipment and device with enlarged functional demands, in high power and multi-frequency. It has all of both faces, EMI(electromagnetic interference) and EMS(electromagnetic susceptibility). In additional, expansion of personal communication system(cellular phone) has many unreliable factor of using time and area, making noise of electromagnetic fields. We studied actual conditions of EMI in the medical site, where is numerous medical equipment, especially central operation room and ICU(intensive care unit), AKR(artificial kidney room : hemo-dialysis unit), etc. The influence, most of medical equipments made electromagnetic nosie has various factors in its band of frequency, harmonics and strength. In the experimental use of electro-surgical unit and cellular phone, noticeable and considerable noise of eletromagnetic fields were measured. All of that can make trouble and errors on the steadiness of bioelectrical devices. In conclusion, It is necessary to reconsiderations of reallocating EMI source vs. EMS factor, and set to definite forbiding area of using cellular phone. For maintenance of steady normal conditions, in spite of existing any other legal standards of safty level, it need considering all of alternative electromagnetic situations on a case-by-case basis.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2003.09a
• /
• pp.43-43
• /
• 2003

목적 : 남, 여 ADHD 환자에서 뇌 혈류상태의 차이점을 알아보기 위하여, 다른 정신과적 질환이 없는 ADHD 환자의 SPECT 뇌혈류 영상에 대하여 SPM을 통한 뇌 혈류상태의 차이점을 비교분석하였다. 대상 및 방법 : 남자 ADHD 환자군 51 명 (4-11세, 평균 9.0세)과 정상군 8명(6-17세, 평균, 9.6세) 그리고, 여자 ADHD 환자군 13명(6-12세 평균 9.0세)과 정상군 4 명(6-12세 평균 9.0세)의 SPECT영상을 비교분석하였다. 방사성의약품 $^{99m}$ Tc-ECD 0.33mCi/kg을 환자의 정맥내에 주사하고 30분후 잠을 재운상태에서 Multi SPECT3 camera를 이용하여 영상을 기록하였다. Matlab을 이용한 SPM program에서 남여별 ADHD환자의 뇌혈류지도 영상을 비교하였으며, BOLD(blood oxygenation level dependent effect) data plotting을 이용하여 혈류증가율과 감소율을 분석하였다. 결과 : 1) 남자 ADHD환자군의 혈류증가부위의 경우, P<0.02 에서 대상회전 (cingulate gyrus)이 나타나 P<0.05까지 한 부위에서만 나타났으며, 정상군에 비하여 15.61%의 혈류증가율을 나타내었다. 혈류감소부위로는 P<0.004에서 좌측 대뇌 도이랑 (insula gyrus), P<0.005에서 우측 대뇌 측두엽이랑, P<0.007에서는 우측 대뇌 전두엽아래이랑에서 각각 감소되었으며 P<0.01에서는 좌측 대뇌 전두엽 아래이랑에서도 나타났다. ADHD 환자군은 정상군에 비하여 각각의 클러스터에서 평균 14.97-15.28%의 혈류 감소율을 보였다. 뇌 혈류의 증가율과 감소율은 유의 수준변화에 영향을 받지 않았다. 2) 여자 ADHD환자의 혈류증가의 경우 P<0.003에서 소뇌 후엽 중앙부위, P<0.005에서는 좌측 대뇌 변연엽, P<0.009에서는 좌측 대뇌 측두엽 그리고 P<0.02에서는 소뇌 후엽을 비롯하여 9개부분에서 혈류증가 클러스터가 나타났으며, ADHD환자군은 정상군에 비하여 24.68-31.25%의 혈류증가율을 나타내었다. 혈류감소를 나타낸 부위로는 P<0.001에서 좌측 대뇌의 렌즈핵(lentiform nucleus), P<0.003에서 우측 대뇌의 렌즈핵 그리고 P<0.005에서 P<0.01까지 좌측 대뇌 측두엽중심에서 나타났다. 각각의 클러스터에서 평균 혈류감소율은 30.57-30.84%이었다. 결론 : 남여ADHD 환자의 혈류 증가와 감소부위는 서로 일치하지 않았으며 여자의 경우 혈류 증가와 감소율이 남자보다 더 크게 나타나, ADHD환자의 SPECT를 이용한 분석에서 남여환자를 동시에 분석하는 것 보다는 남여환자를 구분하여 실시하는 것이 더욱 정확한 진단정보를 제공할 수 있다고 판단된다.

• Journal of Energy Engineering
• /
• v.21 no.1
• /
• pp.26-32
• /
• 2012

This study has been performed Thermal Shock test for analyze the cause of Power drop in PV(Photovoltaic) Module. Thermal Shock test condition was performed with temperature range from $-40^{\circ}C{\sim}85^{\circ}C$. One cycle time is 30min. which are consist of low and high temperature 15min. each other. The test was performed with total 500cycles. EL, I-V were conducted every 100cycle up to 500cycles. Mono Cell resulted in 8% Power drop rates in Bare Cell and 9% in Solar Cell. In the case of Multi Cell resulted in 6% Power drop rates in Bare Cell and 13% in Solar Cell. After Thermal Shock test, Solar Cell's Power drop resulted from surface damages, but in the case of Bare Cell's Power drop had no surface damages. Therefore, Bare Cell's Power drop was confirmed as according to leakage current increase by analysis of Fill Factor after Thermal Shock test. Also, Solar Cell's Power drop rates are higher than that of Bare Cell because of surface damages and consuming electric power increase. From now on, it should be considered that analyzed the reasons of Fill Factor decrease and irregular Power drop in PV module and Cell level using cross section, various conditions and test methods.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.4
• /
• pp.284-291
• /
• 2017

There is no doubt that advances in UAV technology have improved military performance. However, these advances require humans to adapt to new and complex operational systems. UAV has been rapidly expanding to a variety of fields such as reconnaissance, transportation, communication and aerial photographing recently. Also, with the development of UAV automation technology, one operator is able to supervisory-control multiple-UAVs. However, as the number of assigned UAV increases, the amount of information increases and this results in the workload of the operator increasing and deterioration in controlling performance. Accordingly, there is a need for a model to determine the level of overload an operator may encounter with regard to multiple-UAV but nationally this kind of research is currently lacking. Therefore, this paper provides an experimental platform for evaluating workload index effectiveness integrating multiple-UAV operational environments, GCS, and eye-tracking system followed by a limited survey of domestic and international studies of multi-UAV overload studies.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.31 no.6_1
• /
• pp.455-461
• /
• 2013

Kompsat-3 is an optical high-resolution earth observation satellite launched in May 2012. The AEISS sensor of the Korean satellite provides 0.7m panchromatic and 2.8m multi-spectral images with 16.8km swath width from the sun-synchronous near-circular orbit of 685km altitude. Kompsat-3 is more advanced than Kompsat-2 and the improvements include better agility such as in-track stereo acquisition capability. This study investigated the characteristic of the epipolar curves of in-track Kompsat-3 stereo images. To this end we used the RPCs(Rational Polynomial Coefficients) to derive the epipolar curves over the entire image area and found out that the third order polynomial equation is required to model the curves. In addition, we could observe two different groups of curve patterns due to the dual CCDs of AEISS sensor. From the experiment we concluded that the third order polynomial-based RPCs update is required to minimize the sample direction image distortion. Finally we carried out the experiment on the epipolar resampling and the result showed the third order polynomial image transformation produced less than 0.7 pixels level of y-parallax.

• The Korean Journal of Applied Statistics
• /
• v.21 no.1
• /
• pp.141-149
• /
• 2008

Recently we frequently analyze multivariate data with quite large number of variables. In such data sets, virtually duplicated variables may exist simultaneously even though they are conceptually distinguishable. Duplicate variables may cause problems such as the distortion of principal axes in principal component analysis and factor analysis and the distortion of the distances between observations, i.e. the input for cluster analysis. Also in supervised learning or regression analysis, duplicated explanatory variables often cause the instability of fitted models. Since real data analyses are aimed often at multiple purposes, it is necessary to reduce the number of variables to a parsimonious level. The aim of this paper is to propose a practical algorithm for selection of a subset of variables from a given set of p input variables, by the criterion of minimum trace of partial variances of unselected variables unexplained by selected variables. The usefulness of proposed method is demonstrated in visualizing the relationship between selected and unselected variables, in building a predictive model with very large number of independent variables, and in reducing the number of variables and purging/merging categories in categorical data.

• Journal of Korea Water Resources Association
• /
• v.40 no.8
• /
• pp.601-615
• /
• 2007

A selective withdrawal method has been widely used to control the quality of water released from a stratified reservoir and to improve downstream ecosystem habitats. Recently, several existing reservoir withdrawal facilities have been modified to accommodate multi-level water intake capabilities in order to adapt the impact of long-term discharge of high turbidity flow. The purpose of this study was to assess the effect of selective withdrawal method on the control of downstream turbidity and its impact on water quality in Daecheong Reservoir. A laterally integrated two-dimensional hydrodynamic and eutrophication model, which was calibrated and validated in the previous studies, was applied to simulate the temporal variations of outflow turbidity with various hypothetical selective withdrawal scenarios. In addition, their impacts on the algal growth as well as water quality constituents were analyzed in three different spatial domains of the reservoir The results showed that the costly selective withdrawal method would provide very limited benefits for downstream turbidity control during two years of consecutive simulations for 2004-2005. In particular, an excessive withdrawal from the epilimnion zone for supplying upper layer clean water resulted in movement of turbidity plume that contained high phosphorus concentrations upward photic zone, and in turn increased algal growth in the lacustrine zone.

• Korean Journal of Health Education and Promotion
• /
• v.17 no.1
• /
• pp.61-79
• /
• 2000

This study to study and analyze the current state of infancy breast-feeding ＆ practice and related factors and to provide basic data for the effective practice of breast-feeding and breast-feeding percentage improvement. For the object, 474 mothers of the infants who were born between Jan. 1, 1998 and Dec. 31, 1998 were selected, and the survey period ＆ method were from Oct. 15, 1999 through Nov. 14, 1999 (1 month period) and telephone interview, respectively. To examine by month breast-feeding type, the average breast-feeding percentage in 1 month after a child's birth was 42.4%, but after 6 month it decreased to 23.0%. To see breast-feeding percentage by academic background, the breast-feeding of elementary school graduated mothers was 33.3%, which was highest, and it decreased as the academic background of mothers went better (p〈0.01). By employment state, the percentage for the mothers who were not employed was higher (24.6%) than that of those who were employed at the time, which was 8.0% (p〈0.001). There was no meaningful difference found in breast-feeding percentage by infant mothers age, delivery place, infant sex, child order in family, weight at the time of birth. To examine breast-feeding percentage by delivery method, natural delivery was 27.0% which was higher than 13.1% of Caesarean section (p〈0.01), and by breast-feeding experience before leaving the hospital, 35.6% of those who have breast-fed were breast-feeding while it was 16.4% for those who never did it while in the hospital (p〈0.001). After conducting logistics multi return analysis having breast-feeding percentage as a variable at the time of 6 months after babys birth, I found that infant mothers employment state, delivery method, and breast-feeding experience before leaving the hospital become meaningful variables. As unemployed mothers (p〈0.05), as chose natural delivery (p〈0.05), as experienced breast-feeding before leaving the hospital (p〈0.001), there was more tendency to do breast-feeding. Summing the above results, I would like to suggest the following to raise breast-feeding percentage. Firstly, systematic education about the importance and advantages of breast-feeding and correct breast-feeding method should be practised for women. Secondly, vacation before and after childbirth for working women should be practised and the support of systems for working womens breast-feeding such as installation of nursery in work place are needed. Thirdly, continuous publicity and education for natural delivery inducement is necessary, and for the ones who chose Caesarean section, recommendation of breast-feeding is also needed. Fourth, for breast-feeding within fastest time after delivery, rooming-in required and legal and systematic support is also needed. Lastly, in the governmental level, publicity for breast-feeding and breast-feeding recommending programs that promotes 10 rules for successful breast-feeding bringing-up, provided by UNISEF and WHO, are to be provided.

• Journal of the Korea Concrete Institute
• /
• v.17 no.1 s.85
• /
• pp.105-112
• /
• 2005

Stabilizing and rousing sludge water generated from washing truck mixer and batcher plant can resolve inconsistency in quality and improve strength, therefore it is essential to review how to utilize it. This research conducted experiments and studied on solids of sludge water to find out the types of stabilizing agents available in conditions of producing ready mixed concretes in Korea. The result showed that oxy carboxylic acid retarder dedicated for stabilizing sludge water was most effective in decreasing solid. However, the setting time of cement paste was retarded due to surplus reactants, but it did not impede application of ready mixed concretes. When we left the sludge water mixed with stabilizing agent, it has been noted that initial retard effect recovered to the level using just service water in 7${\~}$8 days and that it is effective to use stabilized sludge water in 2${\~}$3 days. On the other hand, saccharic type super retarding agent was also outstanding in applicability by showing similar effect. The sludge water stabilizing agents currently marketed depend on imports, therefore it is necessary to locally manufacture usable stabilizing agents and to review its usability with multi-dimensional view.