• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.72-72
• /
• 2018

A dynamic fatigue characteristic of dental implant system has been evaluated with applying single axial compressive shear loading based on the ISO 14801 standard. For the advanced dynamic fatigue test, multi-directional force and motion needed to be accompanied for more information of mechanical properties as based on mastication in oral environment. In this study, we have prepared loading and motion protocol for the multi-directional fatigue test of dental implant system with single (Apical/Occlusal; AO), and additional mastication motion (Lingual/Facial; LF, Mesial/Distal; MD). As following the prepared protocol (with modification of ISO 14801), fatigue test was conducted to verify the worst case results for the development of highly stabilized dental implant system. Mechanical testing was performed using an universal testing machine (MTS Bionix 858, MN, USA) for static compression and single directional loading fatigue, while the multi-directional loading was performed with joint simulator (ADL-Force 5, MA, USA) under load control. Basically, all mechanical test was performed according to the ISO 14801:2016 standard. Static compression test was performed to identify the maximum fracture force with loading speed of 1.0 mm/min. A dynamic fatigue test was performed with 40 % value of maximum fracture force and 5 Hz loading frequency. A single directional fatigue test was performed with only apical/occlusal (AO) force application, while multi directional fatigue tests were applied $2^{\circ}$ of facial/lingual (FL) or mesial/distal (MD) movement. Fatigue failure cycles were entirely different between applying single-directional loading and multi-directional loading. As a comparison of these loading factor, the failure cycle was around 5 times lower than single-directional loading while applied multi-directional loading. Also, the displacement change with accumulated multi-directional fatigue cycles was higher than that of single directional cycles.

• Journal of the Institute of Convergence Signal Processing
• /
• v.8 no.3
• /
• pp.192-198
• /
• 2007

In this paper, a new method to reduce the size of ROM in the direct digital frequency synthesizer(DDFS) is proposed. The new ROM compression method can reduce the ROM size by using the two ROM. The quantized value of sine is stored by the quantized-ROM(Q-ROM) and the differential ROM(D-ROM). To reduce the ROM size, we use the differential quantization technique with this two ROM. First, we quantize the quarter sine wave with the $2^L$ address and store the quantized value at the Q-ROM. Second, after the $2^L$ address are equally divided into $2^M$ sampling intervals, the sampling value is quantized. And the D-ROM store only the difference between this quantized value and the Q-ROM. So the total size of the ROM in the proposed DDFS is significantly reduced compared to the original ROM. The ROM compression ratio of 67.5% is achieved by this method. Also, the power consumption is affected mostly by this ROM reduction.

• Journal of the Korean Geotechnical Society
• /
• v.28 no.1
• /
• pp.17-27
• /
• 2012

Since geologic data are often sampled at sparse locations, it is important not only to predict attribute values at unsampled locations but also to assess the uncertainty attached to the prediction. In this study the assessment of the local uncertainty of prediction for the thickness of the consolidation layer was performed by using the indicator approach. A conditional cumulative distribution function (ccdf) was first modeled, and then E-type estimates and the conditional variance were computed for the spatial distribution of the thickness of the consolidation layer. These results could be used to estimate the spatial distribution of secondary compression and to assess the local uncertainty of secondary compression for Songdo New City.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.12C
• /
• pp.721-726
• /
• 2011

The compression performance of HEVC (high efficiency video coding) is improved 40%, compared to H.264/AVC. Since the existing 3D video CODEC is based on H.264/AVC or MPEG-2, we can improve the compression performance when we use the proposed stereoscopic video coding method based on HEVC. Since the stereoscopic video has the temporal and inter-view correlations, the videos of the left and right cameras encode together to improve the performance. Especially, we implemented the proposed technique using HM(HEVC test model) 3.4. To compare the performance of the proposed method, we only compare the right view video which is coded using the inter-view prediction. The proposed method which is considered inter-view correlation is improved the performance which BDBR reduce about 36.24% and BDPSNR increase approximately 1.19 dB compared to the separated-coding method.

• Polymer(Korea)
• /
• v.31 no.5
• /
• pp.410-416
• /
• 2007

Monodisperse polymer particles were prepared via one- step seeded polymerization using PMMA as seed particles, and HDDA, triEGDMA or EGDMA as crosslinking monomer. For the study, the effects of 1) the ratio of the absorbed monomer to the seed polymer particles (swelling ratio), 2) the characteristics of crosslinking monomer, 3) electroless Ni plating, and 4) electroless Au Plating on the variation of mechanical properties of polymer particles, such as recovery rate, K-values, breaking strength and breaking displacement were investigated by using MCT (micro compression test). It was observed that swelling ratio of polymer particles influenced only on breaking strength of polymer Particles, while electroless plating did on recovery rate, K-values ($K_{10}\;and\;K_{20}$) and breaking strength of electroless plated polymer particles. However, breaking displacement and K-values ($K_{30}{\sim}K_{50}$) were more or less insensitive to electroless plating.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.12
• /
• pp.842-849
• /
• 2007

For a $CO_2$ two-stage twin rotary compressor used for heat pump water heater system, changes of $CO_2$ solubility in PAG oil were investigated along the gas passages from the first stage suction to final discharge. Only slight changes in solubility took place in suction chambers for both of the first and second stages, but for compression chambers, solubility variation ranged from 0.115 to 0.136, and from 0.133 to 0.182, respectively for the first and second stages. Calculation of gas flashing in parts of leakage oil flows and of oil contained in control volumes due to solubility changes was conducted and included in gas pressure calculation. For the second stage, gas flashing amounts to around $5%\sim6%$ for most leakage flows. Cooling capacity, compressor input, and COP obtained by calculation were well compared to the experimental results. Effects of operation speed on the compressor performance was also studied: as the shaft speed increased, adiabatic efficiency decreased rapidly due to increased over-compression loss.

• Journal of Chest Surgery
• /
• v.36 no.5
• /
• pp.363-366
• /
• 2003

Background: Left ventricular rupture after acute myocardial infarction is a serious complication with high mortality. Emergency operation is usually the only available treatment. A 76-year-old female with persistent chest pain and syncopal attacks was admitted. Transthoracic echocardiography showed the pericardial effusion and generalized hypokinesia of the inferolateral wall of left ventricle. Coronary angiography revealed a total occlusion of the first diagonal branch. After percutaneous transluminal coronary angioplasty with coronary stent and insertion of intraaortic balloon pump, emergency operation was performed. Under cardiopulmonary bypass and cardiac arrest with cold blood cardioplegia, coronary artery bypass graft with saphenous vein, pericardial patch covering on the rupture area with 6-0 polypropylene running sutures, and fibrin glue compression under the patch were performed. We present a case of left ventricular (free wall) rupture after acute myocardial infarction.

• Journal of the Korean GEO-environmental Society
• /
• v.9 no.3
• /
• pp.29-34
• /
• 2008

A large diameter sampler was developed to take undisturbed samples from not only soft ground but also sandy and weathered ground. The large diameter sampler which was developed in Korea Institute of Construction Technology(KICT-type large diameter sampler) was manufactured based on the principle of triple core barrel sampling. A specially designed cutting device was used to cut and contain various kinds of samples in the sampler during a sampling and retrieval procedure. By adjusting the stiffness of the spring located at the top of the sampler, the distance between the cutting shoe and auger can be controlled in accordance with the ground condition. In order to investigate the applicability of the developed sampler and compare the quality of the samples taken by the sampler with that by the traditional thin-walled tube sampler, samples were taken at various sites according to the ground condition. And a series of laboratory tests such as the unconfined compress ion test, triaxial compression test, oedometer test, large diameter Rowe cell consolidation test (D: 150 mm) were performed. The test results showed that the samples by the KICT-type large diameter sampler show higher quality than the samples by the thin-walled tube sampler. And the validity and applicability of the developed KICT-type large diameter sampler was confirmed accordingly.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.438-440
• /
• 2018

Cardiac arrest is a series of conditions that occur when the heart is stopped, regardless of the cause. Cardiac arrest due to heart disease is included in the cause of death in korea every year and is unpredictable. One of the only ways to save a patient's life when a cardiac arrest is cardiopulmonary resuscitation is to maintain circulation through this procedure. The visual information is transmitted to the brain through the optic nerve. Among them, the mittor can see its movement and its shape, and it can be used for correction and analysis. Therefore compared the quality of chest compressions with visual information using mirrors. There was a significant difference in the mean depth of chest compressions($48.93{\pm}6.76$, $53.86{\pm}4.56$, <0.001), and there was also a difference in compression to relaxation ratio($0.87{\pm}0.13$, $0.96{\pm}0.10$, <0.002). There was also a significant difference in attitude awareness($4.93{\pm}0.85$, $8.14{\pm}1.38$, <0.001).

• The Transactions of the Korea Information Processing Society
• /
• v.1 no.4
• /
• pp.541-550
• /
• 1994

A true color image is needed many data on the occasion of the transmission and storage. Therefore, we want to describe color image by a minority data without unreasonableness at eyesight. In this paper, it is presented 256 colormap construction method in RGB, YIQ/YUV space and common colormap expression method at merge between colormaps by reason of dissimilar original color image to display at a monitor for each other colormap at the same time. In comparison with processed result in RGB, YIQ/YUV space, it was measured by PSNR, standard variation, and edge preservation rate using sobel operator. Process time is 3second in colormap construction and 2second in merge between colormaps. In the PSNR value, RGB space has higher 0.15, 0.34 on an average than YIQ and YUV spae. Standard variation has lower in 0.15, 0.41 on an average than Yiq and YUV space. But in the data compression, YIQ/YUV space have about 1/3 compression efficiency than RGB space by reason of use to only 4bit of 8bit in color component.