• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.6
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• pp.343-350
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• 2019

Objectives: The aims of this study were to determine the effectiveness of local compression in patients presenting to the emergency room with intraoral bleeding and to identify when complex haemostatic measures may be required. Materials and Methods: Five hundred forty patients who had experienced intraoral haemorrhage were retrospectively reviewed. The outcome variable was the haemostasis method used, i.e., simple (local compression with gauze) or complex (an alternative method after local compression has failed). Predictor variables were sex, age, American Society of Anesthesiologists (ASA) class, hepatic cirrhosis, bleeding disorder, use of antithrombotic agents, and site/cause of haemorrhage. Results: The mean patient age was 48.9±23.9 years, 53.5% were male, 42.8% were ASA class II or higher, and 23.7% were taking antithrombotic agents. Local compression was used most often (68.1%), followed by local haemostatic agents, sutures, systemic tranexamic acid or blood products, and electrocautery. The most common site of bleeding was the gingiva (91.7%), and the most common cause was tooth extraction (45.7%). Risk factors for needing a complex haemostasis method were use of antithrombotic agents (odds ratio 2.047, P=0.009) and minor oral surgery (excluding extraction and implant procedures; odds ratio 6.081, P=0.001). Conclusion: A haemostasis method other than local compression may be needed in patients taking antithrombotic agents or having undergone minor oral surgery.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.165-170
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• 1998

This paper presents a new prediction method RBP region-based prediction model where the context used for prediction contains regions instead of individual pixels. There is a meaningful property that RBP can partition a cartoon image into two distinctive types of regions, one containing full-color backgrounds and the other containing boundaries, edges and home-chromatic areas. With the development of computer techniques, synthetic images created with CG (computer graphics) becomes attactive. Like the demand on data compression, it is imperative to efficiently compress synthetic images such as cartoon animation generated with CG for storage of finite capacity and transmission of narrow bandwidth. This paper a lossy compression method to full-color regions and a lossless compression method to homo-chromatic and boundaries regions. Two criteria for partitioning are described, constant criterion and variable criterion. The latter criterion, in form of a linear function, gives the different threshold for classification in terms of contents of the image of interest. We carry out experiments by applying our method to a sequence of cartoon animation. We carry out experiments by applying our method to a sequence of cartoon animation. Compared with the available image compression standard MPEG-1, our method gives the superior results in both compression ratio and complexity.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.677-690
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• 1995

In this paper, we propose the high efficiency data compression capable of error control using block-sorting, move to front(MTF) and arithmetic code with variable length in to fixed out. First, the substring with is parsed into length N is shifted one by one symbol. The cyclic shifted rows are sorted in lexicographical order. Second, the MTF technique is applied to get the reference of locality in the sorted substring. Then the preprocessed sequence is coded using VF(variable to fixed) arithmetic code which can be limited the error propagation in one codeword. The key point is how to split the fixed length codeword in proportion to symbol probabilities in VF arithmetic code. We develop the new VF arithmetic coding that split completely the codeword set for arbitrary source alphabet. In addition to, an extended representation for symbol probability is designed by using recursive Gray conversion. The performance of proposed method is compared with other well-known source coding methods with respect to entropy, compression ratio and coding times.

• Journal of Biosystems Engineering
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• v.7 no.1
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• pp.53-61
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• 1982

As an attempt to reduce the consumption of petroleum resources and to improve the performance of a kerosene engine, a series of experiments was conducted using several kinds of ethanol-kerosene blends under the various compression ratios. The engine used in this study was a single-cylinder, four-cycle kerosene engine having a compression ratio of 4.5. To investigate the feasibility of ethanol-kerosene blends in the original engine, kerosene and blends of 5-percent, 10-percent, and 20-percent-ethanol, by volume, with kerosene were used. And to investigate the feasibility of improving the performance of the kerosene engine, a portion of the cylinder head was cut off to increase the compression ratio up to 5.0 by reducing the combustion chamber volume. Kerosene and blends of 30-percent and 40-percent-ethanol, by volume, with kerosene were used for the modified engine with an increased compression ratio. Variable speed tests at wide-open throttle were also conducted at five speed levels in the range of 1000 to 2200 rpm for each compression ratio and fuel type. Volumetric efficiency, engine torque, and brake specific fuel consumption were determined, and brake thermal efficiency based on the lower heating values of kerosene and ethanol was calculated. The results obtained in the study are summarized as follows: A. Test with the original engine: (1) No abnormal conditions were found when burning ethanol-kerosene blends in the original engine. (2) Volumetric efficiency increased with ethanol concentration in blends. When burning blends of 5-percent, 10-percent, and 20-percent ethanol, by volume, with kerosene, average volumetric efficiency increased 1.6 percent, 2.6 percent, and 4.1 percent respectively, than when burning kerosene. (3) Mean engine torque increased 5.2 percent for 5-percent-ethanol blend, 9.3 percent for 10-percent-ethanol blend, and 11.5 percent for 20-percent-ethanol blend than for kerosene. Increase in engine torque when using ethanol-kerosene blends was due to the improved combustion characteristics of ethanol as well as an increase in volumetric efficiency. (4) Up to ethanol concentration of 20 percent, mean brake specific fuel consumption was nearly constant inspite of the difference in heating value between ethanol and kerosene. (5) Brake thermal efficiency increased 0.3 percent for 5-percent-ethanol blend, 3.8 percent for 10-percent-ethanol blend, and 6.8 percent for 20-percent-ethanol blend than for kerosene. B. Test with the modified engine with an increased compression ratio: (1) When burning kerosene, mean volumetric efficiency, engine torque, and brake thermal efficiency were somewhat lower than for the original engine. (2) Engine torque increased 15.1 percent for 30-percent-ethanol blend and 18.4 percent for 40-percent-ethanol blend than for kerosene. (3) There was no significant difference in brake specific fuel consumption regardless of ethanol concentration in blends. (4) Brake thermal efficiency increased 15.0 percent for 30-percent-ethanol blend and 19. 5 percent for 40-percent-ethanol blend than for kerosene.

• Journal of Biomedical Engineering Research
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• v.17 no.1
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• pp.121-128
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• 1996

This paper presents the ECG data compression method referred the adaptive fractal interpolation algorithm. In the previous piecewise fractal interpolation(PFI) algorithm, the size of range is fixed So, the reconstruction error of the PFI algorithm is nonuniformly distributed in the part of the original ECG signal. In order to improve this problem, the adaptive fractal interpolation(AEI) algorithm uses the variable range. If the predetermined tolerance was not satisfied, the range would be subdivided into two equal size blocks. large ranges are used for encoding the smooth waveform to yield high compression efficiency, and the smaller ranges are U for encoding rapidly varying parts of the signal to preserve the signal quality. The suggested algorithm was evaluated using MIT/BIH arrhythmia database. The AEI algorithm was found to yield a relatively low reconstruction error for a given compression ratio than the PFI algorithm. In applications where a PRD of about 7.13% was acceptable, the ASI algorithm yielded compression ratio as high as 10.51, without any entropy coding of the parameters of the fractal code.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.35-40
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• 2001

The exact solution of strength of reinforced concrete RC columns subjected to axial compression combined with biaxial bending needs trial and adjustment procedure to find the depth and inclination of the neutral axis. Thus, approximate methods of analysis and design for biaxial bending are used in practice. Load contour interprets the relation of biaxial bending and equivalent uniaxial bending by u factor which is related to material properties and column shapes. The purpose of this study is to investigate the behavior of high strength RC columns subjected to the combined axial compression and biaxial bending. Fifteen test specimens with dimensions of 200mm$\times$200mm and 4-Dl3 longitudinal steel were examined. The variable of the test is compressive strength of concrete (350, 585, 650kgf/$cm^{2}$), compression load ratio (0.2$P_{o}}$, 0.35$P_{o}}$, 0.5$P_{o}}$), and inclination of loading ($\theta$=0, 22.5, $45^{\circ}$). Test results of coefficient $\alpha$ depending on the compressive strength of concrete are compared with ACI code.

• Geomechanics and Engineering
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• v.12 no.1
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• pp.127-138
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• 2017

A series of high-pressure isotropic compression tests were performed on four types of poorly graded silica sand that were artificially prepared based on representative grading curves and similar mineralogy composition of seabed sediment containing different fines contents existing in the Nankai Trough. The addition of fines steepens the initial compression path and increases the decrement of the void ratio after loading. The transitional behaviour of the poorly graded sand with a larger amount of fines content was identified. The slope of the normal compression line shows a slight decreasing tendency with the level of fines content. The bulk modulus of silica sand with fines was lower when compared with the published results of silica sand without fines. A small amount of particle crushing of the four types of poorly graded sand with variable fines content levels was noticed, and the results indicated that the degree of particle crushing tended to decrease as the fines content increased.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.125-131
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• 1989

This paper proposes a new ABTC (Adaptive Block Truncation Coding) algorithm which improves the BTC algorithm for image data compression. A new adaptive block truncation coding which adopts a selective coding scheme depending on the local characteristics of an image has been described. The characteristics of the ABTC algorithm can be summarized as high compression ratio and the algorithm simplicity. Using this algorithm, color images can be coded at a variable bit rate from 1.0 (bit/pel) to 2.56 (bit/pel) and high compression rate (1.3-105 bit/pel) can be achieved without conspicuous image degradation compared with original images.

• Proceedings of the KOSOMBE Conference
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• v.1994 no.12
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• pp.134-137
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• 1994

In this paper, we describe an approach to ECG data coding based on a fractal theory of iterated contractive transformations defined piecewise. The main characteristic of this approach is that it relies on the assumption that signal redundancy can be efficiently captured and exploited through piecewise self-transformability on a block-wise basis. The variable range size technique is employed to reduce the reconstruction error. Large ranges are used for encoding the smooth waveform to yield high compression efficiency, and the smaller ranges are used for encoding rapidly varying parts of the signal to preserve the signal quality. The suggested algorithm was evaluated using MIT/BIH arrhythmia database. A high compression ratio is achieved with a relatively low reconstruction error.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.371-376
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• 1998

In this study, the size effect of concrete members subjected to the axial load and bending moment is investigated using a series of C-shaped specimens of which test procedure is similar to those of Hognestad, Hanson, and McHenry's. Main test variable is a size ratio of the specimens(1:1/2:1/4) at the concrete compressive strength of 500kg/㎠. Test results show that the flexural compression strength at failure decreases as the size of specimen increases, that is, the size effect law is present. Model equation is derived using regression analyses with experimental data and it is compared with formulas for compressive strength of cylinders and shear strength of beams without stirrups. Size effects is distinct th following sequence; shear strength of beams without stirrups, compressive strength of C-shaped specimens, compressive strength of cylinders.