• 대한원격탐사학회지
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• 제36권5_3호
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• pp.1067-1076
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• 2020

In this paper, an unsupervised saliency guided change detection method using UAV and aerial imagery is proposed. Regions that are more different from other areas are salient, which make them more distinct. The existence of the substantial difference between two images makes saliency proper for guiding the change detection process. Change Vector Analysis (CVA), which has the capability of extracting of overall magnitude and direction of change from multi-spectral and temporal remote sensing data, is used for generating an initial difference image. Combined with an unsupervised CVA and the saliency, Principal Component Analysis(PCA), which is possible to implemented as the guide for change detection method, is proposed for UAV and aerial images. By implementing the saliency generation on the difference map extracted via the CVA, potentially changed areas obtained, and by thresholding the saliency map, most of the interest areas correctly extracted. Finally, the PCA method is implemented to extract features, and K-means clustering is applied to detect changed and unchanged map on the extracted areas. This proposed method is applied to the image sets over the flooded and typhoon-damaged area and is resulted in 95 percent better than the PCA approach compared with manually extracted ground truth for all the data sets. Finally, we compared our approach with the PCA K-means method to show the effectiveness of the method.

• 대한기계학회논문집
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• 제17권6호
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• pp.1547-1555
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• 1993

본 연구에서는 원관외벽에 일정 열유속이 가해지는 스터링 사이클용 가열기 튜브내부로 열전달이 일어나는 경우 원관내부의 유체온도의 시간적 변화를 측정하여 왕복유동에서의 열전달 특성을 규명하고자 하였다. 본 실험에서 사용한 물리적 모델 을 Fig.1에 나타내었으며, 스터링기기에서와 같이 원관의 양끝에서 2개의 피스톤이 90˚의 위상차를 가지면서 왕복운동하도록 설정하였다. 이와같은 왕복유동에서 일정 열유속이 주어진 경우 진동수, 체적 치환비, 원관내부의 평균압력이 온도 및 열전달 특성에 미치는 영향을 실험적으로 규명하였다. 그리고 원관내부 작동 유체의 영향을 규명하기 위해 스터링기기에서 작동유체로 많이 사용되는 헬륨 뿐아니라 공기도 사용 하여 그 결과를 비교하였다.

• 한국항해학회지
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• 제20권1호
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• pp.59-79
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• 1996

Waterfront redevelopment is an element in the process of inner-city regeneration now widespread in many ports of the world. Academic interest in the processes involved has yielded a literature biased towards specific locations rather than towards the analysis of processes and issues. The redevelopment of urban waterfronts does not, of course, occur exclusively in port cities but is found as a continuous process in most places where settlement and water are juxtaposed, whether or not commercial port activity is or was present. Port cities, however, as a result of the concentration and juxtaposition of urban and maritime influences, generally present the major issues involved in waterfront redevelopment most clearly. In this context, the general aim is to explore Korean dimensions of waterfront redevelopment in a range of port cities in a context of inner-urban renewal; and a specific objective is to examine the views of decision-makers in Korean port cities on the processes involved by a questionnaire method. The focus is on comparative strategies, and in particular upon the factors affecting the balance between social goals and commercial interests. To test the response of four categories of decision-makers in Korean port cities on a number of issues perceived as underpinning the processes involved in waterfront redevelopment, four catergories of respondents-port authority representatives(PO), urban planners(UP), port specialists(PS) and city-government official(GO)-were asked to fill in a questionnaire form. In three out of ten cases, the overall result broadly confirmed the a priori expectation; in six cases the confirmation was partial; and in one other the view of respondent was generally contrary to those anticipated. In many, but by no means all, cases there was substantial agreement between the four categories of respondents, but the range of scores was generally much wider than expected.

• Steel and Composite Structures
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• 제35권4호
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• pp.579-598
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• 2020

Consideration of the panel zone (PZ) deformations in the analysis of steel moment frames (SMFs) has a substantial effect on structural response. One way to include the PZ effect on the structural response is Krawinkler's PZ model, which is one of the best and conventional models. However, modeling of Krawinkler's PZ model has its complexity, and finding an alternative procedure for PZ modeling is of interest. In this study, an efficient model is proposed to simplify Krawinkler's PZ model into an Adjusted Rigid-End Zone (AREZ). In this way, the rigid-end-zone dimensions of the beam and column elements are defined through an appropriate rigid-end-zone factor. The dimensions of this region depend on the PZ stiffness, beam(s) and columns' specifications, and connection joint configuration. Thus, to obtain a relationship for the AREZ model, which yields the dimensions of the rigid-end zone, the story drift of an SMF with Krawinkler's PZ model is equalized with the story drift of the same structure with the AREZ model. Then, the degree of accuracy of the resulting relationship is examined in several connections of generic SMFs. Also, in order to demonstrate the applicability of the proposed model in SMFs, several SMFs ranging from 3- to 30-story representing low- to high-rise buildings are examined through linear static and dynamic time history analysis. Furthermore, non-linear dynamic analyses of three SMFs conducted to validate the degree of accuracy of the proposed model in the non-linear analysis of SMFs. Analytical results show that there is considerable conformity between inter-story drift ratio (IDR) results of the SMFs with Krawinkler's PZ model and those of the centerline SMFs with AREZ.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.2018-2025
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• 2019

This study systematically compared two hybrid deterministic/Monte Carlo transport codes, ADVANTG/MCNP and MAVRIC, in solving a difficult shielding problem for a real-world spent fuel storage cask. Both hybrid codes were developed based on the consistent adjoint driven importance sampling (CADIS) methodology but with different implementations. The dose rate distributions on the cask surface were of primary interest and their predicted results were compared with each other and with a straightforward MCNP calculation as a baseline case. Forward-Weighted CADIS was applied for optimization toward uniform statistical uncertainties for all tallies on the cask surface. Both ADVANTG/MCNP and MAVRIC achieved substantial improvements in overall computational efficiencies, especially for gamma-ray transport. Compared with the continuous-energy ADVANTG/MCNP calculations, the coarse-group MAVRIC calculations underestimated the neutron dose rates on the cask's side surface by an approximate factor of two and slightly overestimated the dose rates on the cask's top and side surfaces for fuel gamma and hardware gamma sources because of the impact of multigroup approximation. The fine-group MAVRIC calculations improved to a certain extent and the addition of continuous-energy treatment to the Monte Carlo code in the latest MAVRIC sequence greatly reduced these discrepancies. For the two continuous-energy calculations of ADVANTG/MCNP and MAVRIC, a remaining difference of approximately 30% between the neutron dose rates on the cask's side surface resulted from inconsistent use of thermal scattering treatment of hydrogen in concrete.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.99.1-99.1
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• 2012

The thin-film photovoltaic absorbers (CdTe and $Cu(In,Ga)Se_2$) can achieve solar conversion efficiencies of up to 20% and are now commercially available, but the presence of toxic (Cd,Se) and expensive elemental components (In, Te) is a real issue as the demand for photovoltaics rapidly increases. To overcome these limitations, there has been substantial interest in developing viable alternative materials, such as $Cu_2ZnSnS_4$ (CZTS) is an emerging solar absorber that is structurally similar to CIGS, but contains only earth abundant, non-toxic elements and has a near optimal direct band gap energy of 1.4 - 1.6 eV and a large absorption coefficient of ~104 $cm^{-1}$. The CZTS absorber layers are grown and investigated by various fabrication methods, such as thermal evaporation, e-beam evaporation with a post sulfurization, sputtering, non-vacuum sol-gel, pulsed laser, spray-pyrolysis method and electrodeposition technique. In the present work, we report an alternative aqueous chemical approach based on chemical bath deposition (CBD) method for large area deposition of CZTS thin films. Samples produced by our method were analyzed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, absorbance and photoluminescence. The results show that this inexpensive and relatively benign process produces thin films of CZTS exhibiting uniform composition, kesterite crystal structure, and some factors like triethanolamine, ammonia, temperature which strongly affect on the morphology of CZTS film.

• 디지털콘텐츠학회 논문지
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• 제19권7호
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• pp.1225-1235
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• 2018

본 연구에서는 신체활동 모니터링이 가능한 스마트 의류와 연동되는 스마트 피트니스 콘텐츠와 관련하여 실용성을 갖춘 소비자 맞춤형 스마트 콘텐츠 개발 기획 연구의 일환으로, 타겟소비자의 잠재적 수요를 반영한 셀프트레이닝 지원용 스마트 피트니스 콘텐츠 개발의 구체적인 구현방향을 탐색하였다. 그 결과, 스마트 피트니스 콘텐츠에 대한 잠재적 수요는 시간 경과의 순서에 따라 '운동시작 전'의 단계에서는 '사용 접근성', '흥미유도', '다각적 스토리라인'의 범주어가 도출되었고, '운동수행 중'의 단계에서는 '실시간 음성코칭', '정확한 운동자세 모니터링', '개인 맞춤형 운동처방'이 도출되었다.'운동 직후'의 단계에서는 '실질적 보상제도', '등급제도', '체형변화 모니터링', '일상생활 모니터링'이 도출되었고, '다음 운동으로 연결'의 단계에서는 '동기유발', '높은 지속성' 이 도출되었다.

• 정보관리학회지
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• 제2권1호
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• pp.70-95
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• 1985

본 연구의 목적은 다음의 두 가설을 규명하기 위함이다. 첫째, 온라인 서비스의 특성은 근본적으로는 정보축적 매체의 변형에 따른 참고봉사의 자동화 연장이므로 전통적인 도서관 환경에 온라인 정보검색 서비스를 도입할 경우 궁극적으로 봉사업무를 실행하는 곳은 참고업무 부분이 된다. 따라서 데이터베이스 검색 서비스는 재래식 참고봉사를 보충하고 개선시키면서 완전히 통합될 때에 참고업무 전반에 걸쳐 변화를 줄 것이다. 둘째, 인쇄 출판물 자료속에서 탐색 제한을 받던 참고질문이 데이터베이스 검색 서비스로 가능해 지면, 서비스의 질적 향상과 함께 참고사서의 능률을 증대시킬 것이다. 또한 참고사서에 대한 이미지 향상과 전문직에 대한 인식 고취는 도서관 이용자를 증가시킬 것이다. 이러한 영향을 밝히기 위하여 "DIALOG" 데이터베이스 검색 서비스를 제공하고 있는 4개 전문도서관의 실태를 조사, 분석하여 참고하였다.

• 한국사회복지학
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• 제61권2호
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• pp.371-389
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• 2009

실종아동문제는 한 가정의 문제로 끝나는 것이 아니라 사회문제로 발전할 수 있다는 데에 그 심각성이 있다. 하지만 실종아동문제에 대한 사회적 관심은 초보적인 수준에 머무르고 있다. 본 연구의 목적은 실종아동문제에 대한 사회적 관심을 불러일으키기 위해 아동실종의 사회경제적 비용을 추계하는 것이다. 전체적으로 1명의 장기실종아동이 발생하였을 경우, 약 5억 7천만원 정도의 비용이 발생하였다. 직접비용은 약 6,532만원으로 전체의 11.5%였으며 간접비용은 약 5억원으로 전체의 88.5%였다. 이는 실종을 예방하는 것이 가장 중요하지만, 실종 이후에는 단기간 내 찾기가 매우 중요함을 보여주고 있다. 본 연구결과를 통해 실종으로 인한 사회경제적 비용이 계산되어 실종에 대한 국민의 관심을 유발할 수 있고 예방에 대한 적정 투자비용에 관하여 자료를 추산할 수 있으며, 결과적으로 실종 예방에 대한 적극적인 국가적 투자를 유인할 수 있을 것이다.

• 한국컴퓨터정보학회논문지
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• 제22권1호
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• pp.123-134
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• 2017

The ability to use information technology has become increasingly important as technological advances continue to sweep through the computing world, and education for improving computational thinking has become globally instituted. In South Korea, informatics subjects have been modified in the 2015 curriculum and are now compulsory in primary and secondary education. However, despite substantial financial investment and numerous studies promoting informatics education, there continues to be a serious lack of pre-service teachers capable of teaching computational thinking. This study investigated pre-service teacher programming education using App Inventor, their perceptions of App Inventor, and how use of the program affected teacher problem-solving abilities and self-efficacy. In the pre-test, the control group and experimental group showed no statistically significant difference; however, the post-test revealed that the two groups showed statistically significant differences in problem-solving skills and self-efficacy. The participants initially showed interest in using App Inventor; however, after practice-teaching and project-based learning, the participants demonstrated a growing negativity toward the program when they made errors and the functional limits of App Inventor became apparent. Although most participants stated that they would not use App Inventor in their classes, the positive statistically significant differences in problem-solving skills and self-efficacy indicate that this study could be utilized as a basis for building a teaching-learning program using App Inventor and creating an educational plan for teaching computational thinking.