• Journal of Energy Engineering
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• v.17 no.1
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• pp.23-30
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• 2008

The neutron kinetic analysis methods for the molten-salt reactors are quite different from those for conventional solid-fuel reactors, which do not take into account the flowing-fuel-induced neutronics effects. Therefore, for dynamics and safety analyses of the molten-salt reactor systems, the conventional kinetics codes would not be appropriate to accurately predict its transient behaviors. A point-kinetics with flowing- fuel model has been used to assess the fluid-fuel reactor system safety, but recognized as not to be sufficient to simulate spatial distributions of delayed-neutron precursors and neutron populations during transients for given detail reactor models. In order to meet this requirement, AMBIKIND, a 2-group, 2-dimensional neutron kinetics code suitable for the molten-salt reactor systems was developed. This paper explains the code's theoretical and numerical descriptions and, as a part of its verification, includes some simulation results of MSRE stability experiments. Even though the present reactor model does not include the recirculation effect of the fuel-salt through the reactor system, the AMBIKIN2D code should be able to predict the power and phase shift at various power levels and reactivity insertions with better accuracy.

• Journal of Korea Multimedia Society
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• v.2 no.3
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• pp.231-242
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• 1999

Generally, either caption-based search method or content-based search methods is used to retrieve video information. However, each search method has its limitations. Caption-based search is apt to lose consistency as for user's subjects, and content-based search is hard to extract general means. To enhance efficiency and correctness as for complementing each other, we propose the Integrated Video Data Model(IVDM) which integrates the two search methods, to device the model, we analyze video data and construct the structure of video information hierarchically. IVDM supports caption-based search as assigning meta-data by analyzing thematic-unit in the higher level, and also supports content-based search as extracting feature data by analyzing the content of video data in the lower level. We design Object-Oriented database schema of news video, based-on the IVDM. And we provide 4-type of queries and query processing algorithm to retrieve news video information.

• Journal of the Korea Computer Graphics Society
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• v.18 no.1
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• pp.1-9
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• 2012

Video-based modeling / rendering developed to produce photo-realistic video contents have been one of the important research topics in computer graphics and computer visions. To smoothly combine original input video clips and 3D graphic models, geometrical information of light sources and cameras used to capture a scene in the real world is essentially required. In this paper, we present a simple technique to estimate the position and orientation of an optimal light source from the topology of objects and the silhouettes of shadows appeared in the original video clips. The technique supports functions to generate well matched shadows as well as to render the inserted models by applying the estimated light sources. Shadows are known as an important visual cue that empirically indicates the relative location of objects in the 3D space. Thus our method can enhance realism in the final composed videos through the proposed shadow generation and rendering algorithms in real-time.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.434-445
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• 2018

This study examined whether mobile OTT video service substitutes home TV by using 3 screen data of Nielson-KoreanClick. According to the 2SLS estimation results, when the time spent on mobile OTT video service increased by 1% p, the time spent watching home TV decreased by 12.4%. The results also showed that 1%p increase in the time spent using YouTube app and the mobile OTT video services provided by telecommunication company(Oksusu, Alleh TV, VideoPortal) reduced the time spent on watching terrestrial channels on TV by 16.2% and 23.9%, respectively. The displacement of mobile OTT video service on home TV will be accelerated in the near future. In order to resolve the issue of regulatory unfairness with pay TV services and to safeguard viewer's interests, discussions to establish regulation for OTT video services should be taken place more quickly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.72-80
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• 2018

With the ever increasing advances in computers and their computing power, computational fluid dynamics(CFD) has become an essential engineering tool in the design and analysis of engineering applications. Accordingly, many universities have developed and implemented a course on CFD for undergraduate students. On the other hand, many professors have used industrial examples supplied by computational analysis software companies as CFD examples. This makes many students think of CFD as difficult and confusing. This paper presents a simple CFD example used in the department of mechanical design engineering of Kangwon National University and shows its effectiveness. Most students answered that a simple CFD example is more comprehensive than an industrial example. Therefore, it is necessary to develop simple computational analysis problems in the engineering education field.

• The Journal of the Korea Contents Association
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• v.20 no.7
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• pp.185-194
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• 2020

This study aims to figure out how the brand experience design elements works in the Shortform video-based branding through case analysis. The sense, feel, think, act, relate experience of Shortform video brand are provided through the implementation of specific experience design elements in the process of the creators expressing personality through social media channels and communicating and interacting with consumers. As a result, LIZIQI's food videos provided a brand identity as an 'Eastern gourmet' to consumers through the audiovisual stimulation of food in video, the cognitive reinforcement which is combined of identities and products, and the behavioral participation by web sites·electronic media. In addition, a strong brand relationship was established by sharing emotional ties using human factors and responsibility through co-branding. This can be extended to various Shortform video contents-based branding cases, and it will suggest a useful approach to the brand building strategy through strategic brand experience design elements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.19-24
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• 2009

Structural Dynamics Modification (SDM) is a very effective technique to improve structure's dynamic characteristics by adding or removing auxiliary structures, changing material properties and shape of structure. Among those of SDM technique, the method to change shape of structure has been mostly relied on engineer's experience and trial-and-error process which are very time consuming. In order to develop a systematic method to change structure shape, surface grooving technique is studied and successfully applied to HDD cover model. To verify Surface Grooving Technique, fully embossed HDD cover model was optimized. And comparing with previous optimization result, the effectiveness of this surface grooving technique was checked. The shape of groove and 1 st natural frequency were converged to the same result of previous optimization.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.175-181
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• 2016

This paper introduces a heave compensation system for offshore crane when it gets unexpected disturbances and external force. The dynamic model consists of crane assumed to be the rigid body, hydraulic driven winch, elastic rope and payload. To keep the payload from moving up and down, PD control algorithm is applied. By using the control, the oscillating amplitude of the payload is reduced. Also by using the estimated values involved with time-delay, the relative motion of payload in heave direction is dramatically shortened. This paper shows using the control algorithm with estimated value having time-delay 0.1 second is enough to heave compensation system.

• The Journal of Korean Society for School & Community Health Education
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• v.13 no.2
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• pp.77-91
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• 2012

배경 및 목적: 성병 감염, 조기 성경험, 다수의 성관계 파트너 등과 같은 위험 성행동은 여성의 건강 전반을 위협하는 결과를 초래할 수 있다. 하지만, 이러한 심각성에 비하여, 미국의 청소년기 및 청년기 여성의 위험 성행동을 소수인종 집단별 특성을 고려한 연구는 부족한 실정이다. 그러므로 본 연구는 미국 소수인종 여성 청소년의 위험 성행동에 대한 실태를 조사하고자 한다. 방법: 본 연구는 2차 자료 분석의 결과물로써, 원자료인 미국의 National Longitudinal Study of Adolescent Health (Add Health)의 1기 (1995년)와 3기 (2001년)의 자료 중 여성 청소년의 자료를 바탕으로 분석되었다. 다양한 위험 성행동을 인종별로 분석함과 더불어 본 연구의 특징은 종단적 성병 감염 행태를 인종별로 분석한 점이다. 결과: 본 연구는 소수인종 여성의 위험 성행동에 관한 핵심적인 결과를 제시한다. 성병 감염, 조기 성경험, 다수의 성관계 파트너 등과 같은 위험 성행동의 분포는 흑인과 아시아계 여성이 타인종의 여성에 비하여 높은 위험해 쳐해 있는 것으로 나타났다. 본 연구의 흑인 여성들은 전반적인 성행동을 망라하여 고위험군으로 분류되고 있다. 아시아계 여성 역시 고위험 군으로 분류되는데, 특히, 청소년기에 성병에 한번 감염된 경험이 있는 아시아계 여성은 가장 위험한 성병 감염 행태를 보이고 있는 것으로 나타났다. 결론: 본 연구의 결과는 소수인종 여성의 위험 성행동이 백인보다 전반적으로 높은 편으로 나타나지만, 적절한 보건의료 서비스에서는 소외되는 현실을 지적하고 있다. 이러한 인종별 성건강의 불균형 문제해소를 위하여 청소년들에게 인종적 특성과 서비스 접근성의 고려가 절실히 필요하다고 사료된다.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.420-430
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• 2006

In this paper, we propose a flexible GGOP prediction structure to improve coding efficiency for multi-view video coding. In general, reference software used for MVC uses the fixed GGOP prediction structure. However, the performance of MVC depends on the base view and numbers of B-pictures between I-picture(or P-picture) and P-picture. In order to implement the flexible GGOP prediction structure, the location of base view is decided according to the global disparities among the adjacent sequences. Numbers of B-pictures between I-picture(or P-picture) and P-picture are decided by camera arrangement such as the baseline distance among the cameras. The proposed method shows better result than the reference software of MVC. The proposed prediction structure shows considerable reduction of coded bits by 7.1%.