• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.649-655
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• 2015

In this paper, we propose a defogging algorithm for a single image. Dark channel prior (DCP), which is a well-known defogging algorithm, can cause halo artifacts on boundary regions, low-contrast defogging images, and requires a large computational time. To solve these problems, we use histogram information with DCP on transmission estimation regions and a multi-resolution method. Local histogram information can reduce the low-contrast problem on a defogging image, and the multi-resolution method with edge information can reduce the total computational time and halo artifacts. We validate the proposed method by performing experiments on fog images, and we confirm that the proposed algorithm is more efficient and superior than conventional algorithms.

• Journal of Korean Library and Information Science Society
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• v.53 no.2
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• pp.137-163
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• 2022

The purpose of this study is to develop the public library programs that support the needs of multicultural families by examining the details of their information needs, focusing on the children's education issues of multicultural families. For this purpose, the data on experiences and needs related to the education of multicultural families' children were collected through in-depth interviews with married immigrant women. The study found the following six types of children's education-related needs of multicultural families: 1) Lack of understanding about the educational system and situation of Korean schools, 2) Their children's needs for language and learning 3) Their children's Bilingual education 4) Educational information for the role of parents, 5) Prejudice and discrimination against their children at school 6) Supporting library awareness and experience of mulitcultural families. Based on these needs, the following programs were suggested: 1) Parent role program for children's education, 2) Children's learning program, 3) Children's language education program, 4) Multicultural understanding education, 5) Library user education and guidance.

• Journal of Elementary Mathematics Education in Korea
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• v.6 no.1
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• pp.41-58
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• 2002

This study examines effects of small group cooperative learning on areas of mathematics such as number and calculation, figure, and measurement, and changes of attitude-interest in math in elementary schools. Seventy eight second graders from Jinhae City were divided into the experimental group and the control group. The experimental group was subdivided into small groups of four students who belonged in different levels of math performance. The subdivision was renewed whenever each area was covered. An examination paper which had been developed by Ministry of Education & Human Resources Development and Kyeongsangnamdo Office of Education was given to the subjects. Also, a questionnaire was developed and given to the participants. The results show that, in general, the small group cooperative learning had good effects on the students' ability to solve math problems and, in articular, greater effects on the ability of low-level students. It is revealed that the interaction between the students in small groups affected their attitudes toward and interest in mathematics in a positive way, but did not make perceivable changes in self-confidence of the young Learners.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.117-124
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• 2004

Various multimedia systems have been developed and their application areas widely proliferate. Thus, the interoperability is getting important among various networks and devices. The video transcoding is a technology to solve this interoperability problem among various coding standards. Transcoding can be defined as the conversion of one compressed coded data to another. In this paper, MPEG-2 to MPEG-4 transcoder in the spatial domain is compared with that in the DCT domain. The transcoder is very useful when a video sequence that is originally encoded for digital TV, DVD or satellite broadcasting is served in mobile environment. In order to compare two transcoders, all modules except motion compensation and down sampling are implemented identically. In addition, both transcoders do not search for motion vector. Instead, the decoded information is reused to the encoder. The experimental results show that the transcoder in the spatial domain is usually better than that in the DCT domain with respect to PSNR (Peak Signal-to-Noise Ratio), bitrate and execution time.

• Journal of The Korean Association For Science Education
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• v.29 no.8
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• pp.910-922
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• 2009

The purpose of the study was to investigate the professional level of the Korean non-physics major middle-school science teachers in 'force and motion' content knowledge. For the study, nine science teachers who majored in chemistry, biology, or earth science were sampled from middle-schools in a big city in Korea. The physics concept test-tool (subjective type), which the authors developed, were administered, and then followed by in-depth interviews. The research findings are as follows: Firstly, non-physics major science teachers' correct answer rate in physics knowledge test of secondary school level was not so high that they may have difficulty in teaching correct concepts in physics to middle-school students. Secondly, some teachers show that they can not apply some physics concepts from one to another situation. That means that they may have difficulty in teaching physics conceptual application in various situations to students.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1288-1289
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• 2011

세계가 점차적으로 "전화(電化)"됨에 따라 전기 에너지의 효과적인 분배와 사용이 급격히 중요하게 되었다. 일반 도체를 통한 전류의 흐름은 도체의 저항에 의해 줄열을 발생시켜 전기 에너지의 손실을 일으키고 결국은 에너지와 경제적 자원의 낭비를 초래하게 된다. 초전도체의 저항은 직류 전류에서는 0, 교류 전류에서는 거의 0이기 때문에 초전도체를 이용하면 전력 소자 및 기기의 부피와 무게를 현저히 줄일 수 있는 반면에 모든 전기 시스템의 효율을 향상시킬 수 있고, 에너지 사용의 절감에 따라 환경 문제에 도움을 줄 수 있다. 사고 전류 제한기의 설계에 있어서, 권선형태에 따른 솔레노이드 마그네트와 팬케이크 마그네트를 설계, 제작하여 자장 특성 및 한류 특성을 비교 하였다. 2세대 고온 초전도 선재로 불리는 YBCO 박막형 초전도 선재를 이용하여 동작 전류 증대를 위한 다병렬 솔레노이드 마그네트와 다병렬 팬케이크 마그네트를 제작하였다. 이를 이용하여 440 V/ 630 A급 초전도 사고 전류 제한기와 2 kA 급 대전류 통전 사고 전류 제한 모듈을 설계, 제작하여 단락 특성 시험을 수행하였다. 한편, 자장 응용 기기에 적용 가능한 더블 팬케이크 마그네트를 제 2 세대 초전도선재를 이용하여 설계, 시작하였다. 2세대 선재는 1세대 선재에 비하여 20 T 이상의 외부 자장에 대한 특성이 우수하여 고자장 마그네트 시스템에 더욱 적합하다. 이에 초전도 마그네트 보호를 위한 상전도 영역 전파 실험을 수행하여 CC 선재의 안정도를 측정하였다. 또한 영구전류모드 운전과 플럭스 펌프를 통한 전류 충전에 대한 연구도 병행하였다.

• Annual Conference of KIPS
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• 2009.11a
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• pp.385-386
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• 2009

활성 윤곽선 모델은 스네이크 모델이라고도 하며 영상에서 물체의 경계를 검출하기위한 효과적인 방법으로 사용되고 있다. 본 논문에서는 초기 윤곽선 문제와 효과적인 경계선 검출을 위해 다해상도 기반의 유전자 알고리즘을 이용한 활성 윤곽선 모델을 제안한다. 입력영상의 해상도를 영상 피마리드 기법으로 저해상도로 축소시키고 초기 윤곽선을 설정한다. 설정된 윤곽선상의 연속된 두 좌표를 유전인자로 선택하고, 유전 연산자를 적용하여 물체의 경계를 찾아간다. 경계가 검출된 저해상도 영상을 단계적으로 확대하여, 보간될 영역의 국부적 활성 윤곽선 에너지를 계산하여 최소 에너지를 갖는 위치에 새로운 윤곽선 좌표를 삽입하여 경계를 형성한다. 제안된 방법은 초기 윤곽선의 위치에 상관없이 경계선을 검출했으며, 형태가 복잡한 물체의 경우에도 효과적으로 경계선을 검출하고 계산 복잡도를 감소시켰다.

• Journal of Korean Elementary Science Education
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• v.43 no.1
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• pp.18-34
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• 2024

This study aimed to examine the effects of a science-learning program based on data visualization on the science inquiry and creative problem-solving abilities of elementary school science-gifted students. Accordingly, this research developed a data visualization science-learning program using Tableau, which had twelve sessions. The subjects encompassed 61 students in three gifted classes taught by the researcher. The scientific inquiry ability test and creative problem-solving ability test modified to suit the environment and situation were given to the subjects before and after the treatment. The results confirmed that science learning based on data visualization had no significant impact on basic science inquiry skills. Among the subdomains, significant results were obtained only in the reasoning subdomain. Moreover, integrative inquiry ability was significantly affected, unlike basic inquiry abilities. Among the five subdomains, significant differences were observed in three subdomains (data conversion, data interpretation, and variable control). However, concerning the generation of hypotheses and the control of variables, students exhibited confusion regarding the process of variable control and the exact concept of hypothesis development. This study also evaluated the effects of the program's application on creative problem-solving abilities and found a significant impact. Additionally, it was significantly different in all four subdomains. The results were interpreted to be owing to the students' mastery of Tableau's features, collaborative learning through discussion and debate, and the thematic impact of the data visualization program emphasizing procedural thinking. Finally, this study presented implications for science learning based on data visualization and the future direction of education.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.1-6
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• 2005

The ability to predict radar return from flying vehicles becomes a critical technology issue in the development of stealth configurations. Toward developing a CEM code based on Maxwell's equations for analysis of RCS reduction schemes, an explicit upwind scheme suitable for multidisciplinary design is presented. The DFFT algorithm is utilized to convert the time-domain field values to the frequency-domain. A Green's function based on near field-to-far field transformation is also employed to calculate the bistatic RCS. To verify the numerical calculation the two-dimensional field around a perfectly conducting cylinder is considered. Finally results are obtained for the scattering electromagnetic field around an airfoil in order to illustrate the feasibility of applying CFD based methods to CEM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8A
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• pp.822-828
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• 2002

Optical flow estimation based on multi constraint approaches is frequently used for recognition of moving objects. However, the use have been confined because of OF estimation time as well as error problem. This paper shows a new method form effectively extracting movement information using the multi-constraint base approaches with sobel edge detection. The moving objects anr extraced in the input image sequence using edge detection and segmentation. Edge detection and difference of the two input image sequence gives us the moving objects in the images. The process of thresholding removes the moving objects detected due to noise. After thresholding the real moving objects, we applied the Combinatorial Hough Transform (CHT) and voting accumulation to find the optimal constraint lines for optical flow estimation. The moving objects found in the two consecutive images by using edge detection and segmentation greatly reduces the time for comutation of CHT. The voting based CHT avoids the errors associated with least squares methods. Calculation of a large number of points along the constraint line is also avoided by using the transformed slope-intercept parameter domain. The simulation results show that the proposed method is very effective for extracting optical flow vectors and hence recognizing moving objects in the images.