적응적 프레임 레벨 H.264 비트율 제어

박상현,Park, Sang-Hyun 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.8

본 논문에서는 저전송률 환경에서 영상의 품질을 향상 시키고 전체 영상의 품질 변화를 감소시키는 프레임 레벨 비트율 제어 알고리즘을 제안한다. 제안된 알고리즘에서는 한 GOP에 할당된 비 트량을 버퍼 상태와 전송률뿐만 아니라 각 프레임의 특성에 맞게 적절하게 분배함으로써 전체 영상의 품질을 향상시킨다. H.264 비디오 압축 표준은 다양한 압축 모드 및 최적화 방법을 사용하여 압축률을 향상 시키지만 복잡한 인코더 구조는 정확한 영상 압축 제어를 어렵게 한다. 본 논문에서는 먼저 압축된 영상의 특성을 분석하여 저전송률에 맞는 예측 모델을 제시하고, 이를 이용하여 목표 왜곡 값을 설정하고 목표 왜곡 값에 맞는 비트량을 할당한다. 제안하는 알고리즘과 기존 알고리즘간의 비교 실험은 제안하는 알고리즘이 PSNR 성능에서 기존의 알고리즘 보다 우수함을 보여준다. This paper propose a new frame level rate control algorithm for improving video quality and decreasing quality variation of an entire video sequence in a very low bit rate environment. In the proposed scheme, the allocated bits to a GOP are distributed to each frame properly according to the frame characteristics as well as the buffer status and the channel bandwidth. The H.264 standard uses various coding modes and optimization methods to improve the compression performance, which makes it difficult to control the generated traffic accurately. In this paper, proper prediction models for low bit rate environments are lust proposed, and a target distortion is determined using the models. According to the target distortion, the bit budget is allocated to each frame. It is shown by experimental results that the new algorithm can generate the PSNR performance better than that of the existing rate control algorithm.

비정질실리콘 태양전지에 대한 장시간 성능예측: 확장지수함수 모형 및 컴퓨터 모의실험

박상현,유종훈,Park, S.H.,Lyou, Jong-H. 한국진공학회 2012 Applied Science and Convergence Technology Vol.21 No.4

태양광에 노출되어있는 동안 비정질실리콘 태양전지에서 일어나는 장시간 성능변화에 대해서 연구하였다. 그리고 결함밀도의 운동학 모형을 통해서 태양광으로 인한 태양전지 성능변화를 예측하였다. 특히, 전하운반자 수명이 결함밀도에 의해서 크게 영향을 받기 때문에 비정질실리콘 태양전지의 광유도 성능감소(light-induced degradation)가 확장지수함수 완화법칙(stretched-exponential relaxation)을 따르는 결함밀도에 의해서 물리적으로 설명된다. 그리고 확장지수함수 완화법칙과AMPS-1D 컴퓨터 프로그램의 모의실험에 의해서 비정질실리콘 태양전지의 광유도 성능감소를 계산했고, 모의실험의 결과를 옥외에 설치한 태양전지의 측정데이터에 비교하였다. 본 연구는 상온에서 다음과 같은 특성을 갖는 전형적인 비정질실리콘pin 태양전지에 대해서 모의실험을 진행했다: 두께${\approx}$300 nm, 내부전위${\approx}$1.05 V, 초기 결함밀도${\approx}5{\times}10^{15}cm^{-3}$, 초기 단락전류${\approx}15.8mA/cm^2$, 초기 채우기비율${\approx}0.691$, 초기 개방전압${\approx}0.865V$, 초기 변환효율${\approx}9.50%$. We study for long-term performance of amorphous silicon solar cells under light exposure. The performance is predicted with a kinetic model in which the carrier lifetimes are determined by the defect density. In particular, the kinetic model is described by the stretched-exponential relaxation of defects to reach equilibrium. In this report, we simulate the light-induced degradation of the amorphous silicon solar cells with the kinetic model and AMPS-1D computer program. And data measured for outdoor performances of various solar cells are compared with the simulated results. This study focuses on examining the light-induced degradation for the following amorphous silicon pin solar cells: thickness${\approx}$300 nm, built-in potential${\approx}$1.05 V, defect density (at t=0)${\approx}5{\times}10^{15}cm^{-3}$, short-circuit current density (at t=0)${\approx}15.8mA/cm^2$, fill factor (at t=0)${\approx}0.691$, open-circuit voltage (at t=0)${\approx}0.865V$, conversion efficiency (at t=0)${\approx}9.50%$.

Publish/Subscribe 모델 기반 RPC 미들웨어 설계와 구현

박상현,최준성,국광호,Park, Sanghyun,Choi, Junesung,Kook, Kwangho 한국전기전자학회 2015 전기전자학회논문지 Vol.19 No.3

다양한 형태의 미들웨어가 레거시 시스템과 신규 시스템의 통합을 위해 고안되었다. 미들웨어의 대표적인 형태로는 RPC(Remote Procedure Call), MOM(Message Oriented Middleware), TM(Transaction processing Monitor) 등이 있다. MOM 방식의 대표적인 모델인 PS(Publish/Subscribe)는 시스템의 결합도(coupling)가 낮고 낮은 결합도로 인해 높은 확장성(Scalability)를 얻을 수 있다는 장점이 있으나 한편으로는 응집도(cohesiveness) 또한 낮아진다는 단점이 있다. 이에 비해 RPC 방식은 응집도가 높으나 결합도 역시 높다는 단점이 있다. 본 논문에서는 RPC와 PS의 단점을 서로 상쇄시킬 수 있는 하이브리드 모델의 설계와 구현 방안을 제안한다. Various types of middle-ware were created for integration between legacy systems and newly built systems. RPC(Remote Procedure Call), MOM(Message Oriented Middle-ware) and TM(Transaction processing Monitor) are the typical types of middle-ware. One of the most known MOM type middle-ware is PS(Publish/Subscribe). PS enables to create a system which has low coupling and high scalability. But PS based systems also have low cohesiveness. On the contrary, RPC has high cohesiveness but also has high coupling. This paper proposed design and implementation of hybrid model which offset disadvantages of RPC and PS.

간척의 자취 - 강화섬

박상현,Park Sang-hyun 한국관개배수위원회 1995 한국관개배수논문집 Vol.2 No.2

Digital Design of DWPT Technique on FPGA for Power System Harmonics Estimation

Baraskar Savita,Tiwari Vinay K. 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.6

Real-time detection and quick amplitude estimation of power system harmonics are signifi cant issues among various power quality indices in the electrical power distribution system. In this paper digital design of the discrete wavelet packet transform (DWPT) technique is presented for accurate and fast amplitude estimation of power system harmonics in real-time applications. The DWPT technique provides a uniform frequency bandwidth of the power supply waveform at the output end. Consequently, the input signal's frequency spectrum is evenly divided into eight equal frequency bands that give accurate amplitude estimation of the harmonics by the proposed technique. Generally, the DWPT technique gives the output in the form of coeffi cients, so the proposed digital architecture incorporates arrangements for giving root mean square values directly. The DWPT based wavelet decomposition tree has been developed with the help of MAC-based wavelet fi lters that gives an advantage in saving the number of multipliers compared with the polyphase structure on the FPGA board. Also, the downsampling operation performed at each decomposition level reduces the wavelet coeffi cients by half which minimizes the computations involved in it. The digital design of the proposed DWPT technique has been implemented on the Xilinx Artix-7 FPGA AC-701 board with Xilinx System Generator (XSG)/Vivado design suite 18.3. Thereafter, standard experimental test signals have been generated on the MATLAB/Simulink software platform to validate the robustness and accuracy of the proposed digital hardware under various experimental test conditions, proving their applicability in real-time estimation of power system harmonics.

고유값 분석을 이용한 효과적인 후판의 직선 검출

박상현,김종호,강의성,Park, Sang-Hyun,Kim, Jong-Ho,Kang, Eui-Sung 한국정보통신학회 2011 한국정보통신학회논문지 Vol.15 No.7

본 논문에서는 후판 영상에서 직선 패턴을 검출하는 간단하면서도 정확한 알고리즘을 제안한다. 후판의 직선 검출은 후판 영상으로부터 후판에 관련된 정보를 분석하거나 인식할 때 기본적으로 사용되는 핵심적인 알고리즘이다. 제안하는 알고리즘에서는 마스크를 이용하여 전체 영상을 탐색하면서 에지 영상을 분석한다. 먼저 마스크에 위치한 에지 패턴의 픽셀들에 대한 공분산 행렬을 계산하고 공분산 행렬의 고유값과 에지 패턴의 통계적 기하학적인 특성 사이의 관계를 분석하여 직선 에지를 검출한다. 직선 패턴이 중복된 에지 영상에 대해서는 모든 직선을 정확하게 검출하기 위하여 먼저 각 직선 패턴을 전체 영상에서 분리한 후 고유값을 계산한다. 또한 에지를 구성하는 픽셀의 수와 에지의 방향 정보를 이용하여 불필요한 직선 에지들을 제거함으로써 후판의 직선 에지를 정확하게 검출하도록 한다. 다양한 후판 영상에 대해서 실험을 수행한 결과는 제안하는 알고리즘이 고유값을 이용한 기존 알고리즘 보다 우수함을 보여준다. In this paper, a simple and robust algorithm is proposed for detecting straight line segments in a steel plate image. Line detection from a steel plate image is a fundamental task for analyzing and understanding of the image. The proposed algorithm is based on small eigenvalue analysis. The proposed approach scans an input edge image from the top left comer to the bottom right comer with a moving mask. A covariance matrix of a set of edge pixels over a connected region within the mask is determined and then the statistical and geometrical properties of the small eigenvalue of the matrix are explored for the purpose of straight line detection. Before calculating the eigenvalue, each line segment is separated from the edge image where several line segments are overlapped to increase the accuracy of the line detection. Additionally, unnecessary line segments are eliminated by the number of pixels and the directional information of the detected line edges. The respects of the experiments emphasize that the proposed algorithm outperforms the existing algorithm which uses small eigenvalue analysis.

서암저수지 둑높이기 사업에 따른 지속가능한 지역 발전과 환경 보전 효과 연구

박상현,이근숙,Park, Sang Hyun,Lee, Geun Suk 한국관개배수위원회 2012 한국관개배수논문집 Vol.19 No.1

In recent years, there have been a lot of severe flood and drought disasters and the rural environment have been worsened due to rapid industrialization and urbanization in the river basins of Korea. To prevent such disasters and to improve environment in the era of climate change, Korean Government carried out 110 projects to heighten irrigation dam in the rural area. The study has been carried out to evaluate the heightening work of the irrigation dam for the supply of reserved water and to derive optimal scheme to allocate the water resource for irrigation, domestic demand and environmental conservation as well as to contribute for the rural development in sustainable way. The study is focused on the Seoam Irrigation Dam which has been constructed in 2005 to be connected with the new Gami Reservoir which has been constructed since 2010. In addition, it was studied the contribution effect of the reservoirs for the adjacent comprehensive rural development projects which have been executed by local government. In the study, the principles and visions of sustainable development which have been derived by International Commission on Irrigation and Drainage is applied to estimate the sustainability of the irrigation dams in line with the adjacent comprehensive rural development projects. The project is estimated that the water resource in the reservoirs shall be used integratedly in cooperation with various stakeholders not only to conserve water environment but also to increase productivity of agricultural goods and ecological tour in the rural area.

IPA분석을 통한 미취학 아동 급식의 급식서비스 품질특성 및 급식운영 평가 - 한국·중국·일본의 미취학 아동을 자녀로 둔 부모를 대상으로 -

박상현,주나미,Park, Sanghyun,Joo, Nami 한국식품영양학회 2015 韓國食品營養學會誌 Vol.28 No.1

This study was targeted on the Korean, Chinese, and Japanese parents of preschoolers to investigate the importance and satisfaction of foodservice quality and the importance and performance of foodservice management of the preschool foodservice establishments. The present study conducted a survey on 390 randomly chosen parents of preschoolers (130 Korean, 130 Chinese, and 130 Japanese). Respondents' importance-satisfaction of foodservice quality characteristics and their importance-performance of foodservice management were measured. In order to test for differences between the groups, paired t-test, one way ANOVA, and IPA (Importance-Performance Analysis) were performed. The results were as follows. The importance of foodservice quality was significantly higher than the satisfaction on all items, according to the parents of Korea, China, and Japan. The importance of foodservice quality was higher in Korean parents than in Chinese and Japanese parents. According to ISA results with foodservice quality characteristics, the characteristics with relatively low satisfaction but high importance (II quadrant) was 'Diversity of menu' in both Korean and Chinese parents, and 'Sanitation of tables and chairs' in both Korean and Japanese parents. The importance of foodservice management was significantly higher than performance on all items in Korean, Chinese and Japanese parents. The performance of foodservice management was higher in Chinese than in Japanese and Korean parents. According to IPA results with foodservice management, the management with relatively low performance but high importance (II quadrant) was 'Preparation' in Korean parents, and 'Facility and equipment' in Japanese parents. Therefore, the items with relatively low satisfaction (performance) and high importance should be well-managed.

21세기에도 자본주의는 지속될 것인가?

박상현,Park, Sang-Hyeon 대한출판문화협회 2001 출판저널 Vol.310 No.-

부산교통공사 기술연구원 연구개발 현황

박상현,Park, Sang-Hyeon 한국철도학회 2015 철도저널 Vol.18 No.4