• Title/Summary/Keyword: Compression Rate

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

  • Hwang, Young-Seob;Heo, June;Kim, Uk-Kyu;Park, Seong-Jin;Hwang, Dae-Seok;Kim, Yong-Deok;Chung, In-Kyo;Kim, Kyu-Cheon
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.28 no.6
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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.

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

  • 추은형;김현규;박무훈
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.05a
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    • pp.185-188
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    • 2002
  • With improved network system and development of computer technology, a lot of hospitals are equipping PACS that deals with process and transmission of the medical images. Owing to equipment of PACS the problems on transmission and storage of the medical images were treated. The way to solve the problems is to use various image processing techniques and compression methods This paper describes RLC in lossless image compression method, JPEG using DCT in loss image compression applied to medical images as way implementing DICOM standard. Now the medical images were compressed with Wavelet transform method have been taken advantage of image process. And compression rate of each compression methods was analyzed.

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

  • Sung, Yong-Ha;Jung, Kil-Sung;Choi, Byung-Chul;Lim, Myung-Taeck
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.2
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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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    • v.49 no.3
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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.

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

  • Sin, Gwang-Cheol;Han, Sang-Yong
    • The KIPS Transactions:PartA
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    • v.9A no.3
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    • pp.311-316
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    • 2002
  • LZW is a popular variant of LZ78 to compress text documents. LZW yields a high compression rate and is widely used by many commercial programs. Its core idea is to assign most probably used character group an entry in a dictionary. If a group of character which is already positioned in a dictionary appears in the streaming data, then an index of a dictionary is replaced in the position of character group. In this paper, we propose a new efficient method to find least used entries in a dictionary using counter. We also achieve higher compression rate by preassigning widely used tags in hyper-text documents. Experimental results show that the proposed method is more effective than V.42bis and Unix compression method. It gives 3∼8% better in the standard Calgary Corpus and 23∼24% better in HTML documents.

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

  • Oh, Jae Heun;Choi, Yun Sung;Kim, Dae Hyun
    • Journal of Korean Society of Forest Science
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    • v.104 no.2
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    • pp.198-205
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    • 2015
  • The aim of this study was to provide the basic design parameters for developing logging residue compression machines by investigating compressive deformation characteristics of different types of logging residues. To achieve these objectives, Pinus rigida, Pinus koraensis and Quercus mongolica were selected as specimens, and compression-deformation tests by UTM(universial testing machine) were conducted. The experimental dataset were used to set up the model based on the compression-deformation ratio in the form of exponential function. The results showed that stress coefficient in terms of mechanical properties of logging residues was decreased, whereas strain coefficient tended to be increased as the number of compression increased at target density of $350kg/m^3$ and $400kg/m^3$. The model presented that the required stress was decreased as the number of compression increased, and the stress growth rate was swelled compared to the change of the deformation rate. Therefore, it showed that proper initial compression force was a significant variable in order to achieve the target density of logging residue.

The Effect Analysis of Compression Method on KOMPSAT Image Chain

  • Yong, Sang-Soon;Ra, Sung-Woong
    • Korean Journal of Remote Sensing
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    • v.23 no.5
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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.

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

  • Yang, Hyun-Mo;Kim, Gyoung-Yong
    • Journal of the Korea Convergence Society
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    • v.12 no.7
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    • pp.105-111
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    • 2021
  • The purpose of this study is to determine how the pre-test performed before training affects the results of CPR performance. In the case of the pre-test group(PTG), a pre-evaluation was performed for 1 minute before training, and the group that did not perform the pre-test(NPTG) performed only regular education. In both groups, skill test was performed for 1 minute after training. As a result of comparing the pre and post-test of PTG, there were statistically significant changes in chest compression depth, rate, and compression recoil. There was a statistically significant difference only in the chest compression rate in the chest compression performance results of the two groups after training. There was a statistically significant difference in the results of confidence after training in both groups. It is judged that the pre-test conducted before training has a good influence not only on the results of chest compression, but also on confidence improvement. Therefore, it is judged that it is necessary to develop additional programs such as pre-education test in order to increase the concentration of CPR education for the general population.

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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    • v.5 no.11
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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.

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

  • Jang, Jin-Young;Bae, Choong-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.4
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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.