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관심영역 암호화 시 발생하는 H.264 영상의 비트레이트 오버헤드 최소화 방법 연구
손동열(Dongyeol Son),김지민(Jimin Kim),지청민(Cheongmin Ji),김강석(Kangseok Kim),김기형(Kihyung Kim),홍만표(Manpyo Hong) 한국정보보호학회 2018 정보보호학회논문지 Vol.28 No.2
H.264/AVC-MPEG의 JM v10.2 코드 기반에서 QCIF (176x144) 해상도를 가지는 News 샘플 영상을 사용하여 실험을 하였다. 암호화를 하게 될 관심영역(Region of Interest, ROI)이 H.264 표준의 움직임 예측 및 보상의 특성상 연속적으로 각 프레임마다 불필요하게 참조하여 드리프트를 발생시켰다. 드리프트를 완화하기 위해 암호화가 된 I픽처를 특정 주기로 재삽입하는 최신 관련연구의 방법은 추가 연산량 증가로 이어져 영상 전체의 비트레이트 오버헤드가 증가하는 요인이 된다. 따라서 움직임 예측 및 보상 단계에서 각 프레임마다 암호화가 될 관심영역에서의 Block과 Frame의 참조 탐색 범위를 제한하고, 암호화가 되지 않을 비관심영역에서의 참조 탐색 범위는 정상적인 인코딩 효율을 유지하기 위해 제한하지 않는다. 이와 같이 특정 참조 탐색 범위가 제한된 영상 인코딩을 한 후, 영상 속 개인정보 보호를 위해 얼굴과 같이 개인 식별이 가능한 관심영역에 대해 RC4 비트스트림 암호화 하는 방법을 제안한다. 그리고 동일한 환경의 조건에서 암호화되지 않은 원본 영상과 최신 관련연구 방법과 본 연구의 제안 방법을 각각 구현한 후, 실험 결과들을 비교 · 분석하였다. 최신 관련연구 방법과 다르게 제안방법을 통해 시간상 드리프트를 완화하면서, 제안방법이 적용된 영상 전체의 비트레이트 오버헤드가 원본 영상보다 2.35% 증가되고 최신 관련연구 방법보다 14.93% 감소되었다. 이와 같이 향상된 결과는 본 연구의 실험을 통해 입증하였다. This paper has experimented using News sample video with QCIF (176x144) resolution in JM v10.2 code of H.264/AVC-MPEG. The region of interest (ROI) to be encrypted occurred the drift by unnecessarily referring to each frame continuously in accordance with the characteristics of the motion prediction and compensation of the H.264 standard. In order to mitigate the drift, the latest related research method of re-inserting encrypted I-picture into a certain period leads to an increase in the amount of additional computation that becomes the factor increasing the bit-rate overhead of the entire video. Therefore, the reference search range of the block and the frame in the ROI to be encrypted is restricted in the motion prediction and compensation for each frame, and the reference search range in the non-ROI not to be encrypted is not restricted to maintain the normal encoding efficiency. In this way, after encoding the video with restricted reference search range, this article proposes a method of RC4 bit-stream encryption for the ROI such as the face to be able to identify in order to protect personal information in the video. Also, it is compared and analyzed the experimental results after implementing the unencrypted original video, the latest related research method, and the proposed method in the condition of the same environment. In contrast to the latest related research method, the bit-rate overhead of the proposed method is 2.35% higher than that of the original video and 14.93% lower than that of the latest related method, while mitigating temporal drift through the proposed method. These improved results have verified by experiments of this study.
유동열(Dongyeol Yoo),김재완(Jaewan Kim),조광수(Kwangsoo Cho),범현균(Hyenkyun Beom),권오성(Osung Kwon) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This study describes a numerical simulation technique using finite element method for improvement of US NCAP side impact performance. The side impact analyses were conducted to reduce the injury value of occupant using LS-DYNA. In order to improve side impact performance, the base model was correlated with test results and a many of cases design study were carried out. These were modified front and rear door structure and door trim pad that were affected to dummy injury by direct contact under side impact. In this study, by changing of door structure and door trim pad shape, optimal design for reducing dummy injury value was obtained.
이동열(Dongyeol Lee),방현욱(Hyunwook Bang),김태훈(Taehun Kim) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
Recently, various convenience devices which are named ADAS (advanced drive assist system) are growing trend in the automotive industry. LKAS (lane keeping assist system) is assist system for drivers using forward camera, it has a direct effect on safety. Nowadays robust design validation/verification is very important point because considering quality problems. In this paper, we proposed novel method to validate LKAS initial camera calibration which is validated vehicle test in lab. Test results show that proposed method has advantages not only cross validation regardless of vehicle test but also robustness validation through low/high voltage. It also has better efficient of time and space for validation than vehicle test.
유동열(Dongyeol Yoo),김재완(Jaewan Kim),범현균(Hyenkyun Beom),권오성(Osung Kwon) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_3
This study was described a numerical simulation technique utilizing finite element mothod for the KNCAP side impact. The side impact analyses were conducted to reduce the injury value of occupant using LS-DYNA. In order to improve side impact performance, the base model was correlated with test results and for five cases design study were carried out. These were modified side body structure and driver seat that was affected to dummy behavior by direct contact under side impact. In this study, by reinforcement of body and seat stiffness. optimal design for reducing dummy injury value was obtained.
정동열(Dongyeol Chung),이동규(Donggyu Lee),백종현(Jonh-Hyeon Peck),김정열(Jeong-Yeol Kim),강채동(Chaedong Kang) 대한설비공학회 2022 대한설비공학회 학술발표대회논문집 Vol.2022 No.11
The improvement of the useful energy through the conversion of electric power into thermal energy(P2H) became one of the important issues. Among them, a method to reduce supercooling is being sought as a means to effectively store ice as a ice thermal energy storage system. This study investigated the relationship between the degree of supercooling and the particles through a cooling experiment of pure water containing additives (silica powder, kaolin powder) to understand the effect on the release of supercooling. The sample was constructed by putting each different additives (silica or kaolin) in a test tube and connecting a K-type thermocouple. The sample thus prepared was cooled through a low-temperature thermostat. As a result, it was confirmed that the particle type affects the degree of supercooling.
자동 이득제어 루프를 이용한 CMOS RF 전력 검출기
이동열(Dongyeol Lee),김종선(Jongsun Kim) 대한전자공학회 2014 전자공학회논문지 Vol.51 No.11
본 논문에서는 자동 이득 제어 회로를 이용한 와이드 다이나믹 레인지 RF root-mean-square (RMS) 전력 검출기를 소개한다. 제안하는 자동 이득 제어는 voltage gain amplifier (VGA), RMS 변환 블록, 이득 조절 블록으로 구성되어 있다. VGA는 dB-linear한 이득 관계를 갖는 캐스코드 VGA를 사용하였다. 제안하는 RMS 변환은 입력 신호 전 파장의 제곱 변환을 이용하여 RMS에 비례하는 DC 전압을 출력한다. 제안하는 RMS 전력 검출기는 500MHz에서 5GHz에서 작동하며 검출 범위는 0dBm에서 ?70dBm 이상의 신호를 ?4.53 mV/dBm의 비율로 검출한다. 제안하는 RMS 전력 검출기는 TSMC 65nm 공정을 사용하여 설계되었으며 1.2V에서 5mW의 전력소비를 갖는다. 칩 레이아웃 면적은 0.0097mm²이다. This paper presents a wide dynamic range radio-frequency (RF) root-mean-square (RMS) power detector using an automatic gain control (AGC) loop. The AGC loop consists of a variable gain amplifier (VGA), RMS conversion block and gain control block. The VGA exploits dB-linear gain characteristic of the cascade VGA. The proposed circuit utilizes full-wave squaring and generates a DC voltage proportional to the RMS of an input RF signal. The proposed RMS power detector operates from 500MHz to 5GHz. The detecting input signal range is from 0 dBm to -70 dBm or more with a conversion gain of -4.53 mV/dBm. The proposed RMS power detector is designed in a 65-nm 1.2-V CMOS process, and dissipates a power of 5 mW. The total active area is 0.0097mm².