• 제목/요약/키워드: Compression Rate

검색결과 1,628건 처리시간 0.033초

압축력을 병용한 하악골 신장술 (MANDIBULAR DISTRACTION OSTEOGENESIS WITH COMPRESSION FORCE - BONE DENSITY, HISTOLOGICAL FINDINGS AND TMJ RESPONSE)

  • 황영섭;허준;김욱규;박성진;황대석;김용덕;정인교;김규천
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제28권6호
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    • pp.531-548
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    • 2006
  • The purpose of this study was to investigate the biomechanical, histologic findings of distracted regenerate and TMJ response in modified distraction osteogenesis (DO) technique combined with compression force as biomechanical stimulation method which has been suggested in 2002, and developed thereafter by authors. This study was performed with two experiments. First experiment was designed to explore the optimal ratio of compression force versus distraction force for the new DO technique. Second experiment was planned to evaluate the reaction of TMJ tissue, especially condyle, disc after application of the DO technique with compression force. Total 52 New Zealand adult male-rabbits with 3.0kg body weight were used for the study. For the first study, 30 adult male-rabbits underwent osteotomy at one side of mandibular body and a external distraction device was applied on each rabbit with same manner. In the control group of 10 rabbits, final 8 mm of distraction with 1 mm rate per day was done with conventional DO technique after 5 latency days. For the experimental group of 20 rabbits, a compression force with 1 mm rate per day was added to the distracted mandible on 3-latency day after over-distraction (over-lengthening). As the amount of the rate of compression versus distraction, experimental subgroup I (10 rabbits) was set up as 2 mm compression versus 10 mm distraction (1/5) and experimental subgroup II (10 rabbits) was set up as 3 mm compression versus 11 mm distraction (about 1/3). All 30 rabbits were set up to obtain final 8 mm distraction and sacrificed on postoperative 55 day to analysis on biomechanical, and histologic findings of the bone regenerates. For second study, 22 adult male-rabbits were used to evaluate TMJ response after the DO method application with compression force. In the control group, 10 rabbits was used to be performed with conventional DO method, on the other hand, in a experimental group of 10 rabbits, 10 mm distraction with 2 mm compression (1/5 ratio) was done. The remaining 2 rabbits served as the normal control group. Histomorphologic examinations on both condyle, histological studies on condyle, disc were done at 1, 2, 3, 4, 7 weeks after distraction force application. The results were as follows: 1. On the bone density findings, the experimental group II (force ratio - 1/3) showed higher bone density than the other experimental group (force ratio - 1/5) and control group (control group - $0,2906\;g/cm^2$, experimental group I - $0.2961\;g/cm^2$, experimental group II - $0.3328\;g/cm^2$). 2. In the histologic findings, more rapid bone maturation like as wide lamellar bone site, more trabeculae formation was observed in two experimental groups compared to the conventional DO control group. 3. In morphologic findings of condyle, there were no differences of size and architecture in the condyle in the control and experimental groups. 4. In histologic findings of condyles, there were thicker fiberous and proliferative layers in experimental group than those of control group until 2 weeks after distraction with compression force. But, no differences were seen between two groups on 3, 4, 7 weeks after compression. 5. In histologic findings of disc, more collagen contents in extracellular matrix, more regular fiber bundles, and less elastin fibers were seen in experimental group than control group until 2 weeks after distraction with compression. But, no differences were seen between two groups on 3, 4, 7 weeks after distraction with compression. From this study, we could identify that the new distraction osteogenesis technique with compression stimulation might improve the quality of bone regeneration. The no remarkable differences on TMJ response between control and experimental groups were seen and TMJ tissues were recovered similarly to normal TMJ condition after 3 weeks.

의료영상을 이용한 다양한 압축방법의 구현 및 압축율 비교.분석 (Various Image Compression using Medical Image and Analysis for Compression Ratio)

  • 추은형;김현규;박무훈
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2002년도 춘계종합학술대회
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    • pp.185-188
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    • 2002
  • 컴퓨터의 발달과 네트워크 환경의 개선으로 많은 병원에서는 의료영상을 처리하여 저장하고 전송하는 시스템인 의료영상 저장전송시스템(PACS)을 도입·확대 보급하고 있다. PACS의 도입으로 대용량의 의료 영상을 저장하고 전송하는 문제가 대두되어, 그 해결 방안으로 디지털 영상처리에 사용되고 있는 다양한 영상처리 기법과 압축방법들이 의료영상에 적용되고 있다. 본 논문에서는 의료영상에 다양한 압축방법들을 적용하여 무손실 압축방법으로는 RLC, 손실 압축으로는 DCT를 이용한 JPEG를 DICOM 표준에서 지원하는 방식으로 구현하였다. 또한 현재 영상압축 및 영상처리에 이용되고 있는 Wavelet 변환 방식을 도입하여 의료 영상을 압축하였으며, 의료영상에 적용된 압축방법들의 압축율을 비교·분석하였다.

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급속압축팽창기를 이용한 DME의 HCCI 연소 (HCCI Combustion of DME in a Rapid Compression and Expansion Machine)

  • 성용하;정길성;최병철;임명택
    • 한국자동차공학회논문집
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    • 제15권2호
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    • pp.8-14
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    • 2007
  • Compression ignition of homogeneous charges in IC engines indicates possibilities of achieving the high efficiency of DI diesel engines with low level of NOx and particulate emissions. The objectives of this study are to further understand the characteristics of the HCCI(Homogeneous charge compression ignition) combustion and to find ways of extending the rich HCCI operation limit in an engine-like environment. DME fuel is supplied either in the form of premixture with air or directly injected in the combustion chamber of a rapid compression and expansion machine under the conditions of various equivalence ratio and injection timing. The cylinder pressure is measured and the rate of heat release is computed from the measured pressure for the analysis of the combustion characteristics. The experimental data show that the RCEM can operate without knock on mixtures of higher equivalence ratio, when DME is directly injected in the combustion chamber than introduced as a fraction of a perfect or nearly perfect premixture. Very early fuel injection timings usually employed in HCCI operation are seen to have only insignificant effects in control of ignition timing.

Angio-$Seal^{TM}$ $Evolution^{TM}$ versus Manual Compression for Common Femoral Artery Puncture in Neurovascular Diagnostic Angiography: A Prospective, Non-Randomized Study

  • Chung, Joon-Ho;Lee, Dong-Woo;Kwon, Ok-Sim;Kim, Bum-Soo;Shin, Yong-Sam
    • Journal of Korean Neurosurgical Society
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    • 제49권3호
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    • pp.153-156
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    • 2011
  • Objective : This prospective, non-randomized study compared the safety and efficacy of the Angio-$Seal^{TM}$ $Evolution^{TM}$ to that of manual compression for common femoral artery punctures in neurovascular diagnostic angiography. Methods : From June 2009 to September 2009, we performed 169 diagnostic trans-femoral cerebral angiographies, using either the Angio-$Seal^{TM}$ $Evolution^{TM}$ or manual compression to achieve hemostasis. We included 60 patients in this study, 30 in each group. We defined minor complications as those requiring no further treatment such as hematoma size less than 6 cm and bruise size less than 25 cm. Major complications were those requiring surgery of the femoral artery pseudoaneurysm and/or the second line increase of hospital stay even without further treatment. Results : Mean time to hemostasis was $0.42{\pm}0.04$ minutes for the angioseal and $15.83{\pm}1.63$ minutes for manual compression (p<0.001). Overall complication rate did not differ between the 2 groups. After the patients were fully mobile, at 24 hours, the rate of onset of new complication differed significantly between the 2 groups (p=0.032). In the angioseal group, 5 (16.7%) of the 30 patients experienced the onset of a new complication after 24 hours, including 3 (60.0%) of the 5 who experienced major complications. Conclusion : The Angio-$Seal^{TM}$ $Evolution^{TM}$ is effective at decreasing mean time to hemostasis, like other closing devices. However, it may not be effective at producing early ambulation and discharge, compared to manual compression, because delayed complications may occur significantly after 24 hours.

개선된 LZW 사전 관리 기법에 기반한 효과적인 Hyper-Text 문서 압축 방안 (Hyper-Text Compression Method Based on LZW Dictionary Entry Management)

  • 신광철;한상용
    • 정보처리학회논문지A
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    • 제9A권3호
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    • pp.311-316
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    • 2002
  • LZW 알고리즘은 사전(dictionary) 방식의 압축 알고리즘인 LZ78의 변형된 형태로써 높은 압축률을 제공하기 때문에 많은 상업용 압축 프로그램에서 사용되고 있다. LZW의 핵심은 가장 빈번하게 사용되는 문자열을 사전에 저장하면서, 저장된 것과 동일한 입력 데이터의 문자열을 해당 사전 인덱스로 대체하는 것이다. 본 논문에서는 자주 사용되지 않는 사전의 엔트리를 찾기 위해 카운터를 이용하는 새로운 사전 관리 방법을 제안한다. 또한 하이퍼텍스트 문서를 효율적으로 압축하기 위해 태그와 같은 자주 사용되는 용어들을 코드화하여 사전에 저장한 후 압축을 시도하는 방안을 제안한다. 실험결과 기존의 V.42bis와 UNIX의 compress에 비해 상대적으로 일반문서는 3∼8%, HTML 문서는 23∼24%의 향상된 압축효과를 보여준다.

수종별 벌채부산물의 압축 변형 특성 (Compressive Deformation Characteristics of Logging Residues by Tree Species)

  • 오재헌;최윤성;김대현
    • 한국산림과학회지
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    • 제104권2호
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    • pp.198-205
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    • 2015
  • 본 연구에서는, 수종별 벌채부산물의 압축 변형 특성을 규명함으로써 벌채부산물을 압축할 수 있는 장비의 개발을 위한 기초자료로 사용하고자 하였다. 만능재료시험기(Universial Testing Machine)를 이용한 압축재하 시험장치로 벌채부산물의 3회 반복 압축-변형 특성시험을 통해 수종별 벌채부산물의 목표밀도 압축에 필요한 소요압축력을 구하였다. 리기다소나무(Pinus rigida), 잣나무(Pinus koraiensis), 신갈나무(Quercus mongolica)의 반복 압축 시 응력-변형률 자료를 기반으로 지수함수 형태로 모델화한 것의 물리적 특성 값을 분석한 결과, 목표밀도 $350kg/m^3$$400kg/m^3$ 모두 벌채부산물 기계적 성질에 따른 응력계수는 압축횟수가 늘어나면서 줄어드는 경향을 나타냈으며, 반대로 변형율 계수는 늘어나는 경향을 나타냈다. 모델화를 통해 압축횟수가 증가할수록 압축에 요구되는 소요응력은 줄어들고, 변형율 변화에 비해 응력증가가 커지는 특성이 있으므로, 적절한 초기 압축력이 벌채부산물의 목표밀도 달성에 중요한 변수임을 확인할 수 있었다.

The Effect Analysis of Compression Method on KOMPSAT Image Chain

  • Yong, Sang-Soon;Ra, Sung-Woong
    • 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.

일반인의 심폐소생술 교육에 대한 사전 교육 평가의 영향 (Effect of pre-educational evaluation on CPR education of the General population)

  • 양현모;김경용
    • 한국융합학회논문지
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    • 제12권7호
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    • pp.105-111
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    • 2021
  • 본 연구의 목적은 사전 평가 수행 여부가 심폐소생술 수행 능력 결과에 미치는 영향을 확인하 는 것이다. 사전 평가그룹(PTG)의 경우 교육 전 1분 동안 사전 평가를 수행하였으며 사전 평가를 수행하지 않은 그룹(NPTG)은 정규교육만을 진행하였다. 두 그룹 모두 교육 후 1분 동안 술기 평가를 수행하였다. PTG의 사전 및 사후 평가를 비교한 결과, 가슴 압박의 깊이, 속도, 압박 후 이완에서 통계적으로 유의하게 변화하였다. 두 그룹의 교육 후 가슴 압박 수행 결과에서는 가슴압박 속도에서만 통계적으로 유의한 차이가 있었다. 교육 후 자심감 결과에서는 두 그룹 모두 통계적으로 유의한 차이가 있었다. 훈련 전에 실시한 사전 평가는 가슴 압박의 결과뿐만 아니라 자신감 향상에도 좋은 영향을 미치는 것으로 판단된다. 따라서 일반인을 대상으로 하는 심폐소생술 교육의 집중도를 높이기 위해서는 교육 전 평가 등의 추가적인 프로그램 개발이 필요하다고 판단된다.

Edge Adaptive Hierarchical Interpolation for Lossless and Progressive Image Transmission

  • Biadgie, Yenewondim;Wee, Young-Chul;Choi, Jung-Ju
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제5권11호
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    • pp.2068-2086
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    • 2011
  • Based on the quincunx sub-sampling grid, the New Interleaved Hierarchical INTerpolation (NIHINT) method is recognized as a superior pyramid data structure for the lossless and progressive coding of natural images. In this paper, we propose a new image interpolation algorithm, Edge Adaptive Hierarchical INTerpolation (EAHINT), for a further reduction in the entropy of interpolation errors. We compute the local variance of the causal context to model the strength of a local edge around a target pixel and then apply three statistical decision rules to classify the local edge into a strong edge, a weak edge, or a medium edge. According to these local edge types, we apply an interpolation method to the target pixel using a one-directional interpolator for a strong edge, a multi-directional adaptive weighting interpolator for a medium edge, or a non-directional static weighting linear interpolator for a weak edge. Experimental results show that the proposed algorithm achieves a better compression bit rate than the NIHINT method for lossless image coding. It is shown that the compression bit rate is much better for images that are rich in directional edges and textures. Our algorithm also shows better rate-distortion performance and visual quality for progressive image transmission.

DME 예혼합 압축 착화 엔진에서 밸브 양정과 개폐시기가 내부 배기가스 재순환과 연소에 미치는 영향 (Effect of Valve Lift and Timing on Internal Exhaust Gas Recirculation and Combustion in DME Homogeneous Charge Compression Ignition Engine)

  • 장진영;배충식
    • 한국자동차공학회논문집
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    • 제17권4호
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    • pp.93-100
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    • 2009
  • Intake/exhaust valve timing and exhaust cam lift were changed to control the internal exhaust gas recirculation (IEGR) and combustion phase of homogeneous charge compression ignition (HCCI) engine. To measure the IEGR rate, in-cylinder gas was sampled during from intake valve close to before ignition start. The lower exhaust cam made shorter valve event than higher exhaust cam and made IEGR increase because of trapping the exhaust gas. IEGR rate was more affected by exhaust valve timing than intake valve timing and increased as exhaust valve timing advanced. In-cylinder pressure was increased near top dead center due to early close of exhaust valve. Ignition timing was more affected by intake valve timing than exhaust valve timing in case of exhaust valve lift 8.4 mm, while ignition timing was affected by both intake and exhaust valve timing in case of exhaust valve 2.5 mm. Burn duration with exhaust valve lift 2.5 mm was longer than other case due to higher IEGR rate. The fuel conversion efficiency with higher exhaust valve lift was higher than that with lower exhaust valve lift. The late exhaust and intake maximum open point (MOP) made the fuel conversion efficiency improve.