• 정보처리학회논문지A
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• 제15A권5호
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• pp.269-274
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• 2008

최근 임베디드 시스템의 고성능화에 따라 고해상도의 디스플레이를 채용하고 대용량 멀티미디어 데이터응용 등 다기능을 갖춘 임베디드 프로세서가 다수 발표되고 있다. 이러한 응용 중 실시간 오디오 스트리밍 같은 시간 제한적 응용을 다루어야 하는 모바일 시스템의 경우, 전력, 메모리 용량등 여러 자원이 부족한 상황에 놓이게 된다. 본 논문은 스크래치 패드 메모리에 대하여 활용도를 높이고 저전력을 구현하기 위하여 압축 기법을 스크래치 패드 메모리의 데이터 영역에 구현하였다. 무선 통신과 실시간 오디오 스트리밍에 사용하는 GDM1202 프로세서에 제안한 방법을 구현하여 측정한 결과, 압축으로 얻어진 스크래치 패드의 영역에 코드와 데이터를 추가하여 할당함으로써 13.3% 에너지 절감을 얻을 수 있었으며, 기존의 방법과 동등한 프로그램 수행 성능을 나타냈다.

• 한국정보과학회논문지:시스템및이론
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• 제27권2호
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• pp.117-122
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• 2000

프랙탈 영상 압축은 영상의 일부 영역이 같은 영상의 다른 영역과 거의 유사한 모양을 하고 있다는 자기유사성에 기초하고 있다. 이 압축 방법은 높은 압축률과 빠른 복원력을 제공하지만 매우 긴 압축 시간을 갖는다. 압축 시간을 줄이기 위해 가장 많은 시간이 소요되는 레인지 블록과 도메인 블록간의 비교 탐색 과정을 줄이려는 시도가 꾸준히 이루어져 왔다. 이 연구들은 크게 탐색할 도메인 영역에 제한을 가하는 방법과 도메인 블록의 탐색 순서를 주어진 조건을 만족하는 최초의 도메인을 찾는 방법으로 나누어 볼 수 있다. 그러나 대부분의 프랙탈 영상 압축 기법은 아직도 많은 압축 시간을 필요로 하고 있다. 본 연구에서는 영상 압축 시간을 획기적으로 줄이기 위해 레인지 블록간의 유사성을 이용하여 몇 개의 레인지 플록에 대해서만 도메인 탐색을 시도하는 새로운 방법을 제안한다. 이를 위해 모든 레인지 블록은 각각의 모양을 바탕으로 몇 개의 유사 그룹으로 분류되며, 각 그룹의 대표 블록에 대해서만 도메인 탐색을 실행하게 된다. 또한 이 방법을 다른 프랙탈 영상 압축 기법의 사전 작업으로 활용한다면 더욱 큰 효과를 보게 될 것이다.

• 한국인쇄학회지
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• 제20권1호
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• pp.28-44
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• 2002

Wavelet transformation in image compression is to offer higher image compressibility and high-quality by quantization and entropy encoding. More image quality is good that reconstructed image by wavelet calculation than acquire cosine transform. Therefore, wavelet itself is function if it is wavelet's feature, in this function, do processing applying difference scale and resolution. That is, this is not that fixed resolution has been decided like existent compression way, when it regulated scale, damage goes in pixel and picture looks like break without giving damage entirely in reflex even if magnify or curtail Decoding. Therefore, this paper is in Image that using new wavelet application compression way research that see applies comparing In each image noted this time compressing step by step with circle image compression efficiency recognize. Also, estimated quality pass through by printing of compressed image, investigated compression ratio of most suitable that get print of high quality and elevation of transmission speed.

• 한국통신학회논문지
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• 제25권6B호
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• pp.1028-1040
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• 2000

Since image data has large data amount, proper image compression is necessary to transmit and store the data efficiently. Image compression brings about bit rate reduction but results in some artifacts. This artifacts are blocking artifacts, mosquito noise, which are observed in DCT based compression image, and ringing artifacts, which is perceived around the edges in wavelet based compression image. In this paper, we propose directional postprocessing technique which improved the decoded image quality using the fact that human vision is sensible to ringing artifacts around the edges of image. First we detect the edge direction in each block. Next we perform directional postprocessing according to detected edge direction. Proposed method is that the edge direction is block. Next performed directional postprocessing according to detected edge direction. If the correlation coefficients are equivalent to each directions, postprocessing is not performed. So, time of the postproces ing brings about shorten.

• ETRI Journal
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• 제32권1호
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• pp.163-165
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• 2010

A trend in 3D mesh compression is codec design with low computational complexity which preserves the input vertex and face order. However, this added information increases the complexity. We present a fast 3D mesh compression method that compresses the redundant shared vertex information between neighboring faces using simple first-order differential coding followed by fast entropy coding with a fixed length prefix. Our algorithm is feasible for low complexity designs and maintains the order, which is now part of the MPEG-4 scalable complexity 3D mesh compression standard. The proposed algorithm is 30 times faster than MPEG-4 3D mesh coding extension.

• 한국콘텐츠학회논문지
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• 제5권4호
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• pp.188-196
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• 2005

본 논문에서는 테스트 시간과 전력소모를 감축할 수 있는 새로운 테스트 데이터 압축 및 저전력 스캔 테스트 방법을 제안하였다. 제안된 방법은 수정된 스캔 셀 재배열과 하이브리드 적응적 부호화 방법을 사용하여 scan-in전력과 테스트 데이터 량을 줄였으며 하이브리드 테스트 데이터 압축방법은 Golomb Code와 런길이(run-length) 코드를 테스트 데이터내의 런(run) 길이에 따라서 적응적으로 적용하는 방법이다. 또한 scan-in 전력소모를 최소화하기 위해서 스캔 벡터내의 열 해밍거리를 이용하였다. ISCAS89 벤치마크 회로에 적용하여 실험한 결과, 모든 경우에 있어서 테스트 데이터 및 전력소모를 효율적으로 감소시켰으며 압축률은 17%-26%, 평균 전력소모는 8%-22%, 최고전력소모는 13%-60% 정도의 향상률을 보였다.

• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.33-35
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• 2016

This paper proposes a method utilizing image compression and transmission method for image segmentation in order to reduce the time required in the process of analyzing the image information that has in the image compression process. Many studies of existing with respect to the image segmentation are being studied as a way to split a lot of a particular part in the image. We divide full image into the N equal parts. And it is compressed using the field coding. This will reduce the time-consuming than using the conventional method.

• 대한원격탐사학회지
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• 제23권5호
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• pp.431-437
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• 2007

Multi-Spectral Camera(MSC) on the KOMPSAT-2 satellite was developed and launched as a main payload to provide 1m of GSD(Ground Sampling Distance) for one(1) channel panchromatic imaging and 4m of GSD for four(4) channel multi-spectral imaging at 685km altitude covering l5km of swath width. Since the compression on MSC image chain was required to overcome the mismatch between input data rate and output date rate JPEG-like method was selected and analyzed to check the influence on the performance. In normal operation the MSC data is being acquired and transmitted with lossy compression ratio to cover whole image channel and full swath width in real-time. In the other hand the MSC performance have carefully been handled to avoid or minimize any degradation so that it was analyzed and restored in KGS(KOMPSAT Ground Station) during LEOP(Launch and Early Operation Phase). While KOMPSAT-2 had been developed, new compression method based upon wavelet for space application was introduced and available for next satellite. The study on improvement of image chain including new compression method is asked for next KOMPSAT which requires better GSD and larger swath width In this paper, satellite image chain which consists of on-board image chain and on-ground image chain including general MSC description is briefly described. The performance influences on the image chain between two on-board compression methods which are or will be used for KOMPSAT are analyzed. The differences on performance between two methods are compared and the better solution for the performance improvement of image chain on KOMPSAT is suggested.

• Journal of Advanced Marine Engineering and Technology
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• 제29권2호
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• pp.185-193
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• 2005

The present study composed a diesel-atkinson cycle of high expansion as a method of achieving high efficiency in diesel cycle engines. It also interpreted the cycle engine thermodynamically analysis to determine the possibility of the improvement of thermal efficiency and clarified the characteristics of several factors . According to the result of theoretical analysis, heat efficiency was highest when expansion-compression ratio Reど:1. In addition. diesel engines with high apparent compression ratio had higher expansion-compression ratio than otto engines and consequently their effect of high expansion was high. which in turn enhanced thermal efficiency. When the atkinson cycle was implemented in a real diesel engine by applying the miller cycle through the variation of the closing time of the intake valve, the effective compression ratio and the quantify of intake air decreased and as a result, the effect of high expansion was not observed. Accordingly. the atkinson cycle can be implemented when the quantity of intake air is compensated by supercharge and the effective compression ratio is maintained at its initial level through the reduction of the clearance volume. In this case. heat efficiency increased by $4.1\%$ at the same expansion-compression ratio when the apparent compression ratio was 20 and the fuel cut off ratio was 2. As explained above, when the atkinson cycle was used for diesel cycle. heat efficiency was improved. In order to realize high expansion through retarding the intake value closing time, the engine needs to be equipped with variable valve timing equipment, variable compression ratio equipment and supercharged Pressure equipment. Then a diesel-atkinson cycle engine is realized.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 가을 학술발표회 논문집
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• pp.147-158
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• 2001

In general, two methods have been used to predict settlement of soft ground. One method is Terzaghi's one dimensional consolidation theory which gives time-settlement relationship using the standard consolidation test results. The other is forecasting method of ground settlement to be occured in the future using in-situ monitoring data. The above both methods have some defects in application manner or in itself especially in very deep and soft clayey ground. In view of the lessons and experiences of soft ground improvement projects, several techniques were proposed for more accurate theorectical calculation of consolidation settlement as follows ; ① Subdivision of soft ground, ② Consideration of secondary compression, ③ Using the modified compression index, etc. And also, revised hyperbolic fitting method was suggested to minimize the error of predicted future settlement. In addition, revised De-Beer equation of immediate settlement of loose sandy soil was proposed to overcome the tendency to show too small settlement calculation results by original De-Deer equation. And also, considering the various effects of settlement delay in the improved ground by vertical drains, time-settlement caculation equation(Onoue method) was revised to match the tendency of settlement delay by using the characteristics of discharge capacity decreases of vertical drain with time elapse by the pattern of hyperbolic equation.