• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2262-2275
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• 2022

The Korea Atomic Energy Research Institute (KAERI) studied the sodium-water reaction (SWR) minimized steam generator for the safety of the sodium-cooled fast reactor (SFR), and selected the copper bonded steam generator (CBSG) as the optimal concept. This paper introduces the conceptual design of the CBSG and the development of the CBSG sizing analyzer (CBSGSA). The CBSG consists of multiple heat transfer modules with a crossflow heat transfer configuration where sodium flows horizontally and water flows vertically. The heat transfer modules are stacked along a vertical direction to achieve the targeted large heat transfer capacity. The CBSGSA code was developed for the thermal-hydraulic analysis of the CBSG in a multi-pass crossflow heat transfer configuration. Finally, we conducted a preliminary sizing and rating analysis of the CBSG for the trans-uranium (TRU) core system using the CBSGSA code proposed by KAERI.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.707-714
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• 2022

Versatile Video Coding (VVC) is the most recent video coding standard, which had been developed by Joint Video Expert Team (JVET). It can improve significant coding performance compared to the previous standard, namely High Efficiency Video Coding (HEVC). Although VVC can achieve the powerful coding performance, it requires the tremendous computational complexity of VVC encoder. Especially, affine motion compensation (AMC) was adopted the block-based 4-parameter or 6-parameter affine prediction to overcome the limit of translational motion model while VVC require the cost of higher encoding complexity. In this paper, we proposed the early termination of AMC that determines whether the affine motion estimation for AMC is performed or not. Experimental results showed that the proposed method reduced the encoding complexity of affine motion estimation (AME) up to 16% compared to the VVC Test Model 17 (VTM17).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.497-499
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• 2020

포인트 클라우드는 다수의 3D 포인터를 사용한 3D 데이터의 표현 방식 중 하나이며, 멀티미디어 획득 및 처리 기술의 발전에 따라 다양한 분야에서 주목하고 있는 기술이다. 특히 포인트 클라우드는 3D 데이터를 정밀하게 수집하고 표현할 수 있는 장점을 가진다. 하지만 포인트 클라우드는 방대한 양의 데이터를 가지고 있어 효율적인 압축이 필수적이다. 이에 따라 국제 표준화 단체인 Moving Picture Experts Group에서는 포인트 클라우드 데이터의 효율적인 압축을 위하여 Video based Point Cloud Compression(V-PCC)와 Geometry based Point Cloud Coding에 대한 표준을 제정하고 있다. 이 중 V-PCC는 기존 High Efficiency Video Coding(HEVC) 표준을 활용하여 포인트 클라우드를 압축하여 활용성이 높다는 장점이 있다. 본 논문에서는 V-PCC에 사용하는 HEVC 코덱을 2020년 7월 표준화 완료될 예정인 Versatile Video Coding으로 대체하여 V-PCC의 압축 성능을 더 개선할 수 있음을 보인다.

• YAKHAK HOEJI
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• v.57 no.5
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• pp.357-361
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• 2013

A formal synthesis of Lespedezol $A_1$ has been accomplished. The key feature of this synthesis involves an efficient and powerful palladium-catalyzed cross coupling reaction of diazocarbonyl compound with bis(benzyloxy)phenylboronic acid for the key 3-aryl-chromen-4-one intermediate, which was difficult to be prepared by Suzuki coupling reaction in the previous study. The versatile and efficient synthetic procedure would facilitate synthesis of pterocarpenes and their derivatives.

• The Magazine of the IEIE
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• v.23 no.7
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• pp.37-43
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• 1996

DVD(Digital Versatile Disk)는 CD(Compact Disk)에 비해 약 9배의 저장용량(4.7GByte)을 갖는 디스크로 멀티미디어 시대를 위한 최적의 기록 매채로 그 중요성이 부각되고 있다. Player의 용도 또한 가전 영역인 audio/video system과 computer영역인 DVD-ROM모두에 적용될뿐만 아니라 기존의 모든 CD도 호환되도록 하고 있어 DVD판매 시장이 매우 크게 형성될 것으로 예측하고 있다. 여기에서는 DVD요소 기술과 동향 및 전망, 규격 내용, 그리고 DVD의 시장 동향에 관하여 기술하고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.270-271
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• 2018

본 논문에서는 새로이 시작된 비디오 압축 표준인 VVC(Versatile Video Coding)의 인-루프(in-loop) 필터링을 위한 CNN 구조를 제안한다. 제안하는 CNN 구조는 복호화된 영상을 입력으로 하고 원본 영상과 복호화된 영상의 오차를 손실함수로 사용하여 학습을 진행한다. 또한, 비디오 부호화에서의 다양한 크기의 CU(Coding Unit)를 고려한 다양한 크기의 컨볼루션 필터를 사용하여 특징을 추출하는 구조에 기반하고 있다. 실험을 통하여 제안한 CNN 기반의 필터링이 VVC 의 시험모델인 VTM(VVC Test Model)의 인-루프 필터링의 성능을 개선할 수 있음을 확인하였다.

• Fiber Technology and Industry
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• v.2 no.3
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• pp.376-395
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• 1998

• Optical Science and Technology
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• v.1 no.2
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• pp.17-22
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• 1997

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.250-259
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• 2019

Ophthalmic Laser System is widely used in Selective Laser Trabeculoplasty of Open Angle Glaucoma and Ocular Hypertension. Versatile ophthalmic laser system is a medical device with technology that checks the condition of the treatment area by irradiating a continuous laser pulse on the treatment area, and monitoring the microbubble reaction caused by the temperature increase of the melanosome through the ultrasonic signal and the optical signal sensor. It performs selective laser treatment without damaging the photoreceptor by controlling the wavelength of the laser when microbubbles are detected. This study aims to suggest a guideline for evaluating safety, performance and clinical effectiveness of Versatile Ophthalmic Laser System in accordance with the growing technology. International Standards, Regulations, and Clinical Trial Protocols were investigated and analyzed for this study. As a result of this study, the safety, performance and clinical effectiveness test guideline for Versatile Ophthalmic Laser System were proposed. This guideline will ensure the safety and efficacy of Medical device, and furthermore it is expected to be able to promote the development of technology development by supporting a clinical trial plan.

• Korean Journal of Remote Sensing
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• v.28 no.6
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• pp.693-704
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• 2012

Space-born remote sensing camera systems tend to be developed to have very high performances. They are developed to provide extremely small ground sample distance, wide swath width, and good MTF (Modulation Transfer Function) at the expense of big volume, massive weight, and big power consumption. Therefore, the camera system occupies relatively big portion of the satellite bus from the point of mass and volume. However, the camera systems for lunar exploration don't need to have such high performances. Instead, it should be versatile for various usages under various operating environments. It should be light and small and should consume small power. In order to be used for national program of lunar exploration, electro-optical versatile camera system, called MAEPLE (Multi-Application Electro-Optical Payload for Lunar Exploration), has been designed after the derivation of camera system requirements. A ground model of the camera system has been manufactured to identify and secure relevant key technologies. The ground model was mounted on an aircraft and checked if the basic design concept would be valid and versatile functions implemented on the camera system would worked properly. In this paper, results of design and functional test performed with the field campaigns and air-born imaging are introduced.