• Journal of Biomedical Engineering Research
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• v.40 no.3
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• pp.116-124
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• 2019

The rehabilitation training robots for treating the upper limbs of stroke patients were mainly focused on the upper proximal treatment of it, but recently studies of the distal parts of the upper limbs for rehabilitation of the hand is making some progress even though it is still a small number so far. In this paper, we present the hand robot for the rehabilitation training of stroke patients that is the fingertip contact-typed mechanism, and it has also equipped with the wrist rehabilitation unit to be worked like human hand that enables any movements through mutual cooperation by fingers while picking up or grasping objects. The robot that is presented for this purpose supports the movement of fingers with 5-DoF and the wrist with 3-DoF that moves independently, and operates with a structure that allows the joints of the wrist and fingers to be collaborated organically together to each other. Also, hereby the simulation and evaluation test on its robot mechanism are performed to ensure that fingers with 5-DoF and the wrist with 3-DoF of the serial kinematical mechanism are designed to comply with or exceed ROM for ADL.

• Broadcasting and Media Magazine
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• v.23 no.4
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• pp.58-66
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• 2018

점점 현실화 되는 가상의 환경 내에서 자유롭게 시점을 선택하여 볼 수 있고 전방위 공간 내 몰입형 경험을 제공하는 VR(Virtual Reality) 미디어는 자연스러운 사실감을 제공함과 동시에 공간과 시간의 제약을 극복할 수 있는 실감미디어로 인식되고 있다. 이렇듯 VR 미디어의 출현은 한정된 시점에서의 입체감 및 고화질의 서비스를 제공하는 방식을 벗어나 전방위 시점에서 몰입형 서비스를 제공할 수 있는 발판이 되었으며, 이를 방송 및 통신환경에서 제공하기 위한 기술 개발 및 표준화에 대한 노력이 진행되고 있다. VR미디어는 사용자의 움직임 자유도 지원범위에 따라 3DoF(Degrees of Freedom) 및 6DoF 360VR로 분류되어 단계별 표준화가 추진 중에 있으나, 본 고에서는 3DoF VR 미디어를 중심으로 이를 서비스하기 위한 각 표준화 단체의 동향을 살펴본다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.479.1-479.1
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• 2006

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.259-260
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• 2019

MPEG-I Visual group is actively working on enhancing immersive experiences with up to six degree of freedom (6DoF). In virtual space of 3DoF+, which is defined as an extension of 360 video with limited changes of the view position in a sitting position, looking at the scene from another viewpoint (another position in space) requires rendering additional viewpoints using multiple videos taken at the different locations at the same time. In the MPEG-I Visual workgroup, methods of efficient coding and transmission of 3DoF+ video are being studied, and they released Test Model for Immersive Media (TMIV) recently. This paper presents the enhanced clustering method which can pack the patches into atlas efficiently in TMIV. The experimental results show that the proposed method achieves significant BD-rate reduction in terms of various end-to-end evaluation methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.96-99
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• 2000

We fabricated electroluminescent(EL) devices which have a blended single emitting layer containing poly(N-vinylcarbazole)[PVK] and poly(3-dodecylthiophene)[P3DoDT]. The molar ratio between P3DoDT and PVK changed with 1:0, 2:1 and 1:1. To improve the external quantum efficiency of EL devices, we applied insulating layer, LiF layer, between polymer emitting layer and Al electrode. All of the devices emit orange-red light and its can be explained that the energy transfer occurs from PVK to P3DoDT. In the voltage-current and voltage-light power characteristics of devices applied LiF layer, current and light power drastically increased with increasing applied voltage. In the consequence of the result, the external quantum efficiency of the devices that have a molar ratio 1:1 with LiF layer was 35 times larger than that of the device without LiF layer at 6V.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.250-252
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• 2018

최근 차세대 미디어 중 하나로 가상의 공간내에서 현실적인 경험과 환경을 사용자에게 제공해 줄 수 있는 몰입형 미디어가 각광받고 있다. 이러한 가상현실 세계를 제공할 수 있는 VR미디어의 등장은 몰입형 미디어가 점차적으로 추구하는 실감서비스의 발전 형태를 단적으로 보여주고 있으며 사용자의 움직임에 따라 보다 자연스러운 현실감 및 몰입감을 지원하는 노력이 지속적으로 연구되고 있다. 이러한 추세를 반영하듯, MPEG은 최대 6DoF 사용자 움직임을 지원함과 동시에 고해상도의 VR 해상도를 제공하는 몰입형 미디어 요소기술 개발을 위하여 MPEG-I(Immersive) 표준화를 진행 중에 있다. 본 논문은 종래 3DoF 움직임(회전운동)을 지원함과 동시에 병진운동에 따라 360VR영상 내 가상시점을 매핑함으로써 보다 자연스러운 몰입감을 제공할 수 있는 6DoF지원 360VR 테스트 플랫폼을 제안한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.83-89
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• 2016

In this paper, we apply the complementation principle of five prime substances to reduce the phase interference. The transmitter and receiver match the concepts of co-operative and conflict to the direct and indirect signals. The result shows we investigate the proposed network topology such as 5 prime substances (5 user networks). The key observation is that optimal symmetric degree of freedom (DoF) can be achieved for 5 user network with different channel coherence times by adaptively selecting the interference alignment scheme via controlling the alignment feasibility of the transmitted signals. Theoretical results demonstrate the effectiveness of the proposed 5 user networks are well matched to the wireless mobile channel environment to achieve the symmetric DoF for different channel coherence times which ensures that the proposed networks are applicable for dense wireless network applications. Modulo 3 functionality in 5 user network topology makes it easier for the transmitter cooperation to achieve the DoF of 2/3 with the help of the interference alignment schemes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.4
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• pp.95-106
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• 2017

In this paper, we investigate the conventional topological interference management (TIM) with proposed network topology such as 8 trigram (8 user networks). The key observation is that optimal symmetric degree of freedom (DoF) can be achieved for 8 user network with different channel coherence times by adaptively selecting the interference alignment scheme via controlling the alignment feasibility of the transmitted signals. However, this yields a very complex problem, for which we use the combination of different schemes such as interference avoidance and repetition coding. In addition to the above schemes, we propose a triangular transmit cooperation (TTC) algorithm for 8 user networks to achieve the optimal symmetric DoF. And We apply the principle of complementarity of 8 trigram to remove the interferences, and correspond the concepts of win-win and conflict to direct and indirect signals of transmit and receive respectively. We find that the principle of complementarity comes out from the trigram of I Ching. That is, we apply the relation of confrontation and coexistence to 8 transmitters and receivers, and get the results of symmetric DoF of 4/3.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.166-168
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• 2020

MPEG 비디오 그룹은 MPEG-I 표준의 일부로 포인트 클라우드(Point Cloud) 압축을 위한 비디오 기반 포인트 클라우드 부호화(V-PCC)와 몰입형(immersive) 비디오 압축을 위한 MPEG Immersive Video(MIV) 표준을 개발하고 있다. 최근에는 포인트 클라우드 및 몰입형 비디오와 같은 체적형(volumetric) 비디오를 모두 압축할 수 있도록 V-PCC 와 MIV 를 통합한 V3C(Visual Volumetric Video-based Coding) 표준화를 진행하고 있다. 본 논문에서는 V3C 코덱을 사용한 3DoF+(3 Degree of Freedom plus) 비디오 부호화 방안을 분석한다. 또한 V3C 코덱의 2D 코덱으로 기존 HEVC 대신 VVC 를 사용할 경우의 부호화 성능 향상을 분석한다.

• Journal of Broadcast Engineering
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• v.24 no.7
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• pp.1209-1220
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• 2019

The demand for virtual reality (VR) is rapidly increasing. Providing the immersive experience requires much operation and many data to transmit. For example, a 360-degree video (360 video) with at least 4K resolution is needed to offer an immersive experience to users. Moreover, the MPEG-I group defined three degrees of freedom plus (3DoF+), and it requires the transmission of multiview 360 videos simultaneoulsy. This could be a burden for the VR streaming system. Accordingly, in this work, a bitrate-saving method using projection conversion is introduced, along with experimental results for streaming 3DoF+ 360 video. The results show that projection conversion of 360 video with 360lib shows a Bjontegaard delta bitrate gain of as much as 11.4%.