• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.6
• /
• pp.1003-1010
• /
• 2020

This paper investigates the achievable data rate for the single-user decoding(SUD) receiver, which does not perform successive interference cancellation(SIC), in contrast to the conventional SIC non-orthogonal multiple access(NOMA) scheme. First, the closed-form expression for the achievable data rate of SUD NOMA with correlated information sources(CIS) is derived, for the stronger channel user. Then it is shown that for the stronger channel user, the achievable data rate of SUD NOMA with independent information sources(IIS) is generally inferior to that of conventional SIC NOMA with IIS. However, for especially highly CIS, we show that the achievable data rate of SUD NOMA is greatly superior to that of conventional SIC NOMA. In addition, to verify the impact of CIS on the achievable data rate of SUD, the extensive comparisons of the achievable data rates for the SUD receiver and the SIC receiver are compared for various correlation coefficients.

• Journal of the Korea Computer Graphics Society
• /
• v.28 no.2
• /
• pp.21-28
• /
• 2022

ASTC is one of the standard texture formats supported in OpenGL ES 3.2 and Vulkan 1.0 (and later versions), and it has been increasingly used on mobile platforms (Android and iOS). ASTC's most important feature is the block size configuration, thereby providing a trade-off between compression quality and rates. With the higher number of textures, however, it is difficult to manually determine the optimal block sizes of each texture. To solve the problem, we present a new approach based on PSNR values to automatically determine the ASTC block size. A brute-force approach, which compresses a texture on all block sizes and compares the PSNR values of the compressed textures, can increase the compression time by up to 14 times. In contrast, our three-step approach minimizes the compression-time overhead. According to our experiments on a texture set including 64 various textures, our method determined the block sizes from 4×4 to 12×12 and reduced the size of compressed files by 68%.

• Journal of Broadcast Engineering
• /
• v.28 no.1
• /
• pp.100-108
• /
• 2023

In hybrid block-based video coding, transform coding converts spatial domain residual signals into frequency domain data and concentrates energy in a low frequency band to achieve a high compression efficiency in entropy coding. The state-of-the-art video coding standard, VVC(Versatile Video Coding), uses DCT-2(Discrete Cosine Transform type 2), DST-7(Discrete Sine Transform type 7), and DCT-8(Discrete Cosine Transform type 8) for primary transform. In this paper, considering that DCT-2, DST-7, and DCT-8 are all linear transformations, we propose an inverse transform that reduces the number of multiplications in the inverse transform by using the linearity of the linear transform. The proposed inverse transform method reduced encoding time and decoding time by an average 26%, 15% in AI and 4%, 10% in RA without the increase of bitrate compared to VTM-8.2.

• The KIPS Transactions:PartB
• /
• v.9B no.6
• /
• pp.745-752
• /
• 2002

The purpose of the paper is to enable a format transcoding between a heterogeneous compression format in a real time, and to enhance the compression ratio using characteristics of the compressed frame. In this paper, for the heterogeneous format transcoding, we tried to transcode from MPEG2 having a lower compression ratio to H.263 having a higher compression ratio. After analyzing MPEG 2 bit stream and H.263 bit stream of the same original video, we found that the number of intra coded macro blocks in MPEG 2 data is much higher than the number of the intra coded macro blocks in H.263 data. In the process of P frame generation, a intra coded macro block is generated when a motion estimation value representing the similarity between the previous frame and current frame does not meet a threshold. Especially the intra coded macro block has a great impact on the compression ratio. Hence the paper, we tried to minimize the number of intra coded macro blocks in H.263 data stream which is transcoded from MPEG 2 in a compressed domain. For the purpose, we propose a guided search method for transcoding the INTRA coded block into INTER coded block using the information about motion vectors surrounding the intra macro block in order to minimize the complexity of the motion estimation process. The experimental results show that the transcoding of MPEG 2 into H.263 can be done in a real time successfully.

• 한국공간정보시스템학회:학술대회논문집
• /
• 2003.11a
• /
• pp.78-83
• /
• 2003

OGC(Open GIS Consortium, Inc.)에서 2000년에 XML의 지리정보 처리를 위한 GML 1.0이 제안된 이후 최근 GML 3.0이 발표되기까지 국제적으로는 다양한 GIS 응용분야에서 GML을 현실 문제에 이용하고자 하는 시도가 이루어지고 있다. 현재 우리나라에서도 국가 GIS(NGIS)에서 GML을 도입하여 국내 표준안으로 추진하고자 다양한 기반연구가 진행되고 있다. 본 연구는 중요한 GIS 응용중의 하나인 지질자원 정보 분야에서 GML을 활용하기 위한 기반연구로서 우리나라의 표준 지질도(또는 수치지질정보)와 기타 지질자원 정보 인프라 구축에 적용될 수 있는 다양한 지구과학자료를 대상으로 하였다. 따라서 본 연구에서는 지질자원 분야에서의 GML 응용을 위한 기반 데이터 모델과 이를 처리하기 위한 아키텍처를 UML 기법으로 설명하고, 이를 바탕으로 시험 구현된 운용환경에서 실제 대상 지역을 선정하여, 연구지역에 대한 지질자원 정보의 GML 적용 사례를 제시하고자 한다. 이를 위한 연구 내용으로는 수치 지질도를 XML-GML의 기본 스키마구조에 따라 엔코딩한 뒤, 주제정보의 표현을 위한 XSLT, SVG 파일 변환 처리 등을 수행하였다. 결론적으로 본 연구는 지질자원 분야의 정보화 인프라 구축을 목적으로 하는 기초 시험연구로 수행되었는 바, 우리나라에서는 2001년 이후 GIS 수치 주제도로서 수치 지질도의 보급이 활성화되면서, 이 정보를 제작/공급하는 기관이나 업무에 사용하는 기관 등에서 GML 기반으로 데이터를 제작하거나 운용이 가능할 것으로 생각된다. 또한, 다른 분야에서 GIS 주제정보를 다루는 경우에도 GML을 주제정보와 연계하여 현실 문제에 적용이 가능한 창조 모델로 이용될 수 있을 것으로 생각된다.}94,\;29.4{\pm}30.3,\;45.1{\pm}44$로 Mel 10군과 Mel 30군이 유의적인 감소를 보였으나(p<0.05) 이들 두 군 간의 차이는 나타나지 않았다. 이상의 결과로, 랫트에서 복강수술 후 melatonin 10mg/kg투여가 복강 내 유착 방지에 효과적이라고 생각된다.-1}{\cdot}yr^{-1}$로서 두 생태계에 축적되었다.여한 3,5,7군에서 PUFA 함량이 증가한 반면, SFA 함량은 감소하여 P/S 비율, n-3P/n-6P 비율은 증가하는 경향이었으며 이는 간장의 인지질, 콜레스테롤 에스테르, 총 지질의 지방산조성에서도 같은 경향을 볼 수 있었다.X>$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 대부분을 차지하였다. 야생 돌복숭아 과육 중의 지방산 조성은 포화지방산이 16.74%, 단불포화지방산 17.51% 및 다불포화지방산이 65.73%의 함유 비율을 보였는데, 이 중 다불포화지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 지질 구성 총 지방산의 대부분을 차지하는 함유 비율을 나타내었다.했다. 하강하는 약 4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실

• Geophysics and Geophysical Exploration
• /
• v.3 no.2
• /
• pp.53-60
• /
• 2000

The server/client systems using the web protocol and distribution computing environment by network was applied to the MT data processing based on the Java technology. Using this network based system, users can get consistent and stable results because the system has standard analysing methods and has been tested from many users through the internet. Users can check the MT data processing at any time and get results during exploration to reduce the exploration time and money. The pure/enterprised Java technology provides facilities to develop the network based MT data processing system. Web based socket communication and RMI technology are tested respectively to produce the effective and practical client application. Intrinsically, the interpretation of MT data performing the inversion and data process requires heavy computational ability. Therefore we adopt the MPI parallel processing technique to fit the desire of in situ users and expect the effectiveness for the control and upgrade of programing codes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.4A
• /
• pp.336-344
• /
• 2005

Discrete Wavelet Transform(DWT) is the oncoming generation of compression technique that has been selected for MPEG4 and JEPG2000, because it has no blocking effects and efficiently determines frequency property of temporary time. In this paper, we propose an efficient bit-serial architecture for the low-power and low-complexity DWT filter, employing two-channel QMF(Qudracture Mirror Filter) PR(Perfect Reconstruction) lattice filter. The filter consists of four lattices(filter length=8) and we determine the quantization bit for the coefficients by the fixed-length PSNR(peak-signal-to-noise ratio) analysis and propose the architecture of the bit-serial multiplier with the fixed coefficient. The CSD encoding for the coefficients is adopted to minimize the number of non-zero bits, thus reduces the hardware complexity. The proposed folded 1D DWT architecture processes the other resolution levels during idle periods by decimations and its efficient scheduling is proposed. The proposed architecture requires only flip-flops and full-adders. The proposed architecture has been designed and verified by VerilogHDL and synthesized by Synopsys Design Compiler with a Hynix 0.35$\mu$m STD cell library. The maximum operating frequency is 200MHz and the throughput is 175Mbps with 16 clock latencies.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.5
• /
• pp.56-65
• /
• 2009

Stereoscopic images consist of the left image and the right image. Thus, stereoscopic images have much amounts of data than single image. Then an efficient image compression technique is needed, the DPCM-based predicted coding compression technique is used in most video coding standards. Motion and disparity estimation are needed to realize the predicted coding compression technique. Their performing algorithm is block matching algorithm used in most video coding standards. Full search algorithm is a base algorithm of block matching algorithm which finds an optimal block to compare the base block with every other block in the search area. This algorithm presents the best efficiency for finding optimal blocks, but it has very large computational loads. In this paper, we have proposed fast disparity estimation algorithm using motion and disparity vector information of the prior frame in stereo image coding. We can realize fast disparity vector estimation in order to reduce search area by taking advantage of global disparity vector and to decrease computational loads by limiting search points using motion vectors and disparity vectors of prior frame. Experimental results show that the proposed algorithm has better performance in the simple image sequence than complex image sequence. We conclude that the fast disparity vector estimation is possible in simple image sequences by reducing computational complexities.

• The KIPS Transactions:PartB
• /
• v.9B no.5
• /
• pp.571-578
• /
• 2002

In this paper, we propose a video sequence coding scheme called AMV (Auxiliary Motion Vector) to minimize error propagation caused by transmission errors over the Internet. Unlike the conventional coding schemes the AMY coder, for a macroblock in a frame, selects two best matching blocks among several preceding frames. The best matching block, called a primary block, is used for motion compensation of the destination macroblock. The other block, called an auxiliary block, replaces the primary block in case of its loss at the decoder. When a primary block is corrupted or lost during transmission, the decoder can efficiently and simply suppress error propagation to the subsequent frames by replacing the block with an auxiliary block. This scheme has an advantage of reducing both the number and the impact of error propagations. We implemented the proposed coder by modifying H.263 standard coding and evaluated the performance of our proposed scheme in the simulation. The simulation results show that AMV coder is more efficient than the H.263 baseline coder at the high packet loss rate.

• Journal of agriculture & life science
• /
• v.45 no.6
• /
• pp.265-278
• /
• 2011

Effects of the open level of the side window were studied to control the temperature and relative humidity in the fog cooling greenhouse. The greenhouse was cooled by air atomizing spray nozzles of the air and water two-fluid process. The control process includes the measuring of environmental variables, setting and coding of the water balance equations and heat balance in greenhouse, calculating of the roof window open and spray water, and operating of the motor and pump. The target temperature and relative humidity were set at $28^{\circ}C$, 75%, respectively. The three modes of the side window open level were 0%, 50% and 100%. The average dry bulb temperatures of the inside air were 28.2, 27.2 and $26.3^{\circ}C$, respectively and their standard deviation was ranged from $0.4^{\circ}C$to $0.8^{\circ}C$. Also the relative humidity of the 0% mode was the best controlled one with the average of 76.3% and the standard deviation of 2.1%.