• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.277-284
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• 2001

Recently, with development of mechanics of materials, as pursuing the high speed of the ships, a demanding of composite construction which satisfies high strength and low weight at the same time is iner casing. A sandwich element is a type of composite construction, which is composed of thin, strong, stiff and relatively high density faces and a think, light, and weaker core material. As 2nd moment is increased by faces is separated from the neutral axis farther, a sandwich element is most effective light structural form. In this paper, the make a comparative study Aluminum Honeycomb Sandwich Panel(AHSP) and Aluminum Pyramid Sandwich Panel(APSP).

• Structural Engineering and Mechanics
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• 제50권4호
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• pp.471-486
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• 2014

The number of explosive attacks on civilian structures has recently increased. Protection of structure subjected to blast load remains quite sophisticated to predict. The use of the pyramid cover system (PCS) to strengthen sandwich structures against a blast terror has great interests from engineering experts in structural retrofitting. The sandwich steel structure performance under the impact of blast wave effect is highlighted. A 3-D numerical model is proposed to study the PCS layer to strengthen sandwich steel structures using finite element analysis (FEA). Hexagonal core sandwich (XCS) steel panels are used to study structural retrofitting using the PCS layer. Field blast test is conducted. The study presents a comparison between the results obtained by both the field blast test and the FEA to validate the accuracy of the 3-D finite element model. The effects are expressed in terms of displacement-time history of the sandwich steel panels and pressure-time history effect on the sandwich steel panels as the explosive wave propagates. The results obtained by the field blast test have a good agreement with those obtained by the numerical model. The PCS layer improves the sandwich steel panel performance under impact of detonating different TNT explosive charges.

• Journal of Contemporary Eastern Asia
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• 제23권1호
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• pp.58-82
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• 2024

Former South Korean President Moon Jae-in implemented a project called the Peace Initiative, which prioritized a "peaceful and prosperous Korean Peninsula" as the core national agenda and involved using a peace-based frame instead of a unification approach to address inter-Korean relations from a different perspective. This initiative was evaluated in this study using a revised version of the pyramid model to assess the input-output-result process underlying the project and determine whether it generated results that differed from those achieved by the previous administration. To these ends, this research compared Moon's key presidential speeches with those of his predecessor, Park Geun-hye, as input, news commentaries and responses from major players as output, and the trend of perceptional and attitudinal changes in public opinion as results. Although Moon failed to accomplish significant policy effects on inter-Korean relations because of geopolitical challenges and the transfer of power to the conservative party, the analysis revealed that the input, output, and partial results of inter-Korean dialogue reflect some progress.

• 디지털융복합연구
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• 제18권9호
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• pp.265-275
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• 2020

손상부담은 우리사회에서 매우 심각한 것으로 널리 인식되고 있다. 그럼에도 불구하고 손상감시에 필요한 데이터가 충분하지 않다. 이 연구의 목적은 손상감시를 위해 핵심 데이터를 선택하고 보완하는 것이다. 이를 위해 본 연구에서는 통계품질 6가지 차원에 따라 '사망원인통계', '건강보험통계', '퇴원손상조사'에 대한 품질평가보고서 등의 문헌을 분석 하였다. 분석결과는 '사망원인통계'와 '건강보험통계'가 손상감시를 위한 핵심데이터로서 유용성이 있다는 것이다. 그러나 '건강보험통계'에는 손상외인에 대한 데이터가 부족하다는 단점이 있다. 단점을 보완하기 위해, 본 연구에서는 국민건강보험 의료비 청구 시 의료기관이 손상외인을 의무적으로 신고하도록 하는 제도를 제안한다. 이 제도의 결과로서 우리는 '손상 피라미드 구축', '국민연금과의 데이터 연계', '손상 데이터의 시의성 향상'을 기대할 수 있다. 그리고 이 제도 실현을 위한 후속 연구를 기대한다.

• 한국자기공명학회논문지
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• 제14권2호
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• pp.55-75
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• 2010

An ion-exchanged reaction of $MnCl_2$ with Al-incorporated solid core/mesoporous shell silica (AlSCMS) followed by calcinations generated manganese species, where average oxidation state of manganese ion is 3+, in the mesoporous materials. Dehydration results in the formation of $Mn^{2+}$ ion species, which can be characterized by electron spin resonance (ESR). The chemical environments of the manganese centers in Mn-AlSCMS were investigated by diffuse reflectance, UV-VIS and ESR spectroscopic methods. Upon drying at 323 K, part of manganese is oxidized to higher oxidation state ($Mn^{3+}$ and $Mn^{4+}$) and further increase in (average) oxidation state takes place upon calcinations at 823 K. It was found that the manganese species on the wall of the Mn-AlSCMS were transformed to tetrahedral $Mn^{3+}$ or $Mn^{4+}$ and further changed to square pyramid by additional coordination to water molecules upon hydration. The oxidized $Mn^{3+}$ or $Mn^{4+}$ species on the surfaces were reversibly reduced to $Mn^{2+}$ or $Mn^{3+}$ species or lower valances by thermal process. Mn(II) species I with a well resolved sextet was observed in calcined, hydrated Mn-AlSCMS, while Mn (II) species II with g = 5.1 and 3.2 observed in dehydrated Mn-AlSCMS. Both species I and II are considered to be non-framework Mn(II).

• 제어로봇시스템학회논문지
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• 제16권12호
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• pp.1233-1240
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• 2010

In the flat panel display and semiconductor industries, the visual alignment system is considered as a core technology which determines the productivity of a manufacturing line. It consists of the vision system to extract the centroids of alignment marks and the stage control system to compensate the alignment error. In this paper, we develop a Kalman filter algorithm to estimate the alignment mark postures and propose a coarse-fine alignment control method which utilizes both original fine images and reduced coarse ones in the visual feedback. The error compensation trajectory for the distributed joint servos of the alignment stage is generated in terms of the inverse kinematic solution for the misalignment in task space. In constructing the estimation algorithm, the equation of motion for the alignment marks is given by using the forward kinematics of alignment stage. Secondly, the measurements for the alignment mark centroids are obtained from the reduced images by applying the geometric template matching. As a result, the proposed Kalman filter based coarse-fine alignment control method enables a considerable reduction of alignment time.

• 융합신호처리학회논문지
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• 제2권4호
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• pp.31-37
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• 2001

버스 전용차선 번호판 인식 시스템은 차량 검출 및 영상 획득 , 번호판 영역 추출 개별문자 추출, 문자인식 및 데이터 전송의 5가지 핵심부분으로 구성된다. 이 중에서도 번호판 추출의 정확성은 전체 시스템 인식률에 지대한 영향을 줄 수 있는 부분이며 다양한 날씨 및 주위 환경 변화에서도 정확한 추출을 요구한다. 본 논문에서는 검출 시간의 단축을 위해 획득된 영상을 피라미드 구조로 만든 후 번호판 템플릿의 영역을 이진화하고 번호판의 분포를 가지는 후보영역을 추출한다. 추출된 후보 영역 중 번호판 문자 분포의 특성을 이용한 검증과정을 통해 최종영역을 추출하는 방법을 제안한다. 제안된 방법을 버스 전용차선 도로에서 획득한 영상에 적용한 결과 다양한 날씨와 주위 환경변화에서도 번호판 영역이 정확이 추출됨을 확인하였다.

• Smart Structures and Systems
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• 제29권1호
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• pp.195-206
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• 2022

Crack detection is essential for inspection of existing structures and crack segmentation based on deep learning is a significant solution. However, datasets are usually one of the key issues. When building a new dataset for deep learning, laborious and time-consuming annotation of a large number of crack images is an obstacle. The aim of this study is to develop an approach that can automatically select a small portion of the most informative crack images from a large pool in order to annotate them, not to label all crack images. An active learning method with difficulty learning mechanism for crack segmentation tasks is proposed. Experiments are carried out on a crack image dataset of a steel box girder, which contains 500 images of 320×320 size for training, 100 for validation, and 190 for testing. In active learning experiments, the 500 images for training are acted as unlabeled image. The acquisition function in our method is compared with traditional acquisition functions, i.e., Query-By-Committee (QBC), Entropy, and Core-set. Further, comparisons are made on four common segmentation networks: U-Net, DeepLabV3, Feature Pyramid Network (FPN), and PSPNet. The results show that when training occurs with 200 (40%) of the most informative crack images that are selected by our method, the four segmentation networks can achieve 92%-95% of the obtained performance when training takes place with 500 (100%) crack images. The acquisition function in our method shows more accurate measurements of informativeness for unlabeled crack images compared to the four traditional acquisition functions at most active learning stages. Our method can select the most informative images for annotation from many unlabeled crack images automatically and accurately. Additionally, the dataset built after selecting 40% of all crack images can support crack segmentation networks that perform more than 92% when all the images are used.

• 지역연구
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• 제15권2호
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• pp.131-153
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• 1999

Since 1980's there have been two trends that obviously developed in the would -- economics globalization and urban internationalization. China, with is reform and opening-up policy and rapid economic growth, keeps pace with these two trends. The term "International City" has no putative standard or definition. If we make an analogue of urban functional hierarchy in the world with a pyramid, the International Citiesa are the few elites on its top. The highest level international cities can be called "World City" or "Global City". In today's new international division of labor, they are diversified leading cities with control capacity on a world scale, like New York, London, and Tokyo. The secondary international cities are either diversified cities with influence and regulative functions on multinational scale or specialized cities on politics, economics, culture, or other aspects with worldwide impact. Judged by different criteria, there is no city that is qualified as International City with the exception of Hong Kong, which was returned to the P.R. of China in 1997. Nevertheless, Some favorable conditions for the development of the international city still exist in China. This country is already the sixth largest economic entity in the world, and the second largest economic entity in the world, and the second largest one if GNP estimated by ppp. Furthermore its import and export value make up for 40% of its GNP, indicating that China is repidly merging into global economy. In this 1, 2 billion-population country, the difference of economic levels between urban and rural, coastal and inland regions is so big that a few metropolises in the coastal region have the possibilities and potentials to develop into international cities regardless of rather low GNP per capita of the whole country. This article will focus on analysis from several perspectives, such as the proportion of foreign trade values in GDP, the proportion of imports and exports by foreign funded enterprises in total foreign trade value; distribution of the 500 largest foreign-funded enterprises; distribution of the 500 enterprises with largest import and export values; distrigbution of foreign computer and telecom companies with offices in China; the number of outward flights per week and the international tourists; the value of foreign capital used in cities and so on. From this analysis, it is predicted that Chinese international cities will surely emergy from the eastern coastal regions and they must be the core cities of metropolitan interlocking regions that have been formed or in the process of forming. Those international cities will arise from south to north in turn : Hong Kong-Guangzhu, Shanghai, Beijing-Tianjin, and perhaps the last one is Dalian-Shenyang. The other side of this issue is that there is a long way for the coming international cities in China except Hong Kong. At least China and these core cities must continually devote to (1) improve the regional composition of foreign capital sources. (2) improve the composition of export commodities. (3) improve the investment environment (including hard and soft environment) to attract more transnational corporations to settle. (4) deepen the reform of state-owned enterprises and establish Chinese own transnational corporations to enter the world market.ons to enter the world market.

• 한국과학교육학회지
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• 제33권5호
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• pp.1041-1054
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• 2013

본 연구의 목적은 여러 학문에서 다루는 개념과 다양한 현상을 포괄하여 설명할 수 있는 원리가 되는 Big idea를 중심으로 교육과정에 기반을 둔 통합과학 교육과정(standard based integrated science curriculum) 틀을 설계하는 것이다. Big idea에 대한 학습을 통하여 학생들은 개별적인 사실 및 이론을 통합할 수 있을 뿐 아니라 영역 특정적인 지식들에 대한 총체적인 이해를 도모할 수 있다. 이를 위하여 2009 개정 과학과 교육과정에 제시된 초 중등학교 과학의 내용 영역을 분석하여 필수학습요소를 추출하였다. 필수학습요소들을 분석하고 범주화하는 과정을 거쳐 통합의 중심이 되는 네 개의 Big idea인 '다양성', '구조', '상호작용', '변화'를 선정하였다. 지식 피라미드를 이용하여 각각의 Big idea에 속하는 내용지식과 이들을 포괄할 수 있는 학문 내 개념, 간학문적 개념들을 위계적으로 나타내었다. 또한 Big idea를 중심으로 교육과정을 설계할 때 방향을 제시할 수 있는 본질적 질문들을 각각의 Big idea마다 제시하였다. 개발한 통합과학 교육과정 틀을 이용하여 교육 현장에 적용할 수 있는 방법을 구체화한 예시 모듈을 개발하였다.