• The Journal of Korean Academy of Prosthodontics
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• v.34 no.2
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• pp.373-383
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• 1996

In order to compare the accuracy of impression method using addition silicone putty impression material, metal master die was fabricated with 4 cylindrical abutments that were similar in shape to mandibular arch. Among the 4 abutments, two(A, D) with 8mm width and 7mm height were formed in the 2nd molar regions and the other two(B, C) with 6mm width and 7mm height were on the canine regions. Impressions were taken using one-step putty wash impression technique and two-step putty wash impression technique by three different types of impression materials(Perfect, Express, Exaflex). Upon measuring the distance between the abutments on the model by three dimensional measuring machine, the percent of devitaion of the materials were obtained, rendering the following results. The results obtained are as follows : 1. There was no significant difference in accuracy in regard with the impression method between one-step putty wash impression technique and two-step putty wash impression technique using addition silicone putty impression material. 2. There were no difference in accuracy among with three different addition silicone putty impression materials. 3. All the distances between abutments on improved stone models increased in comparison with those on the metal master model.

• Journal of Korean Society of Steel Construction
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• v.29 no.3
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• pp.193-204
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• 2017

Fatigue strength of temporary steels and painted structural steels corroded under outdoor atmospheric environments is not clear. In this study, fatigue tests were carried out on steel plates which were cut off from 7-year-old temporary structural member under subway construction environment and from 75-year-old Yeongdo bridge member under marine atmospheric environment. After removing corrosion production on the steel surface, 3-dimensional surface geometry of the corroded steel was measured at intervals of $1.0{\times}1.0mm$, and corrosion characteristics such as minimum, maximum and mean values of residual thicknesses were calculated. From the fatigue test and FEM analysis results, the relationship between corrosion characteristics and fatigue behavior was presented, and change in fatigue strength of the unpainted and painted steels corroded in outdoor environments was also presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4069-4074
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• 2010

Phase change of calcium carbontae crystals in crystallization of precipitated calcium carbonate was researched by adding additives such as ethylenediaminetetraacetic acid(EDTA), diethylenetriaminepentaacetic acid(DTPA), citric acid(CIT) and pyromellitic amid(PMA). At low temperature $20^{\circ}C$, calcite crystal was made. At high temperature $80^{\circ}C$, aragonite crystal was made without additives. At middle temperature $40^{\circ}C$ and $60^{\circ}C$, Aragonite crystal also made by adding EDTA, DTPA. The crystal growth of Aragonite was retarded by the presence of CIT, PMA and the single phase of calcite was made. It was found that additives were important factors to make the single phase of calcium carbonate.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.1
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• pp.30-41
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• 2007

The backbone molecular dynamics of the C-terminal part of the mouse Cdt1 protein (tCdt1, residues 420-557) was studied by high field NMR spectroscopy. The Secondary structure of this protein was suggested by analyzing of chemical shift of backbone atoms with programs TALOS and PECAN, together with NOE connectivities from 3D $^{15}N-HSQC-NOESY$ data. Measurement of dynamic parameters $T_1,\;T_2$ and NOE and limited proteolysis experiment provided information for domain organization of tCdt1(420-557). Analysis of the experimental data showed that the C-terminal part of the tCdt1 has well folded domain for residues 455-553. The residues 420-453 including ${\alpha}-helix$ (432-441) are flexible and probably belong to other functional domain in intact full length Cdt1 protein.

• Journal of Biosystems Engineering
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• v.34 no.1
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• pp.63-68
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• 2009

This study was carried out to determine necessary conditions for optimal ventilation of small windowless piglet house (5.2 (W) ${\times}$ 12.3 (L) ${\times}$ 2.3 (H) m) with negative tunnel ventilating system using CFD (Computational Fluid Dynamics) simulation. The weaning piglet house for this experiment was consisted of 4 rooms (520 (W) ${\times}$ 300 (L) cm), 3 fences (70 (H) cm), 1 air inlet (350 (W) ${\times}$ 2 (H) cm) and 1 exhaust fan (50 (D) cm), and simulated using CFD code, FLUENT. The simulation results for the original weaning piglet house showed ununiform ventilation for each room. Therefore, to uniformly ventilate all rooms, the heights of the air inlet and first fence were modified to 3 cm and 100 cm, respectively. The simulation result f3r the modified weaning piglet house showed uniform ventilation for all rooms and the optimum air inlet velocity of 1.4 m/s.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.722-733
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• 2006

In scalable streaming application, there are two important knobs to tune to effectively exploit the underlying network resource and to maximize the user perceivable quality of service(QoS): layer selection and packet scheduling. In this work, we propose Semantics Aware Packet Scheduling (SAPS) algorithm to address these issues. Using packet dependency graph, SAPS algorithm selects a layer to maximize QoS. We aim at minimizing distortion in selecting layers. In inter-frame coded video streaming, minimizing packet loss does not imply maximizing QoS. In determining the packet transmission schedule, we exploit the fact that significance of each packet loss is different dependent upon its frame type and the position within group of picture(GOP). In SAPS algorithm, each packet is assigned a weight called QoS Impact Factor Transmission schedule is derived based upon weighted smoothing. In simulation experiment, we observed that QOS actually improves when packet loss becomes worse. The simulation results show that the SAPS not only maximizes user perceivable QoS but also minimizes resource requirements.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.559-567
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• 2018

Objective : The aim of this study was to evaluate the effect for biodegradable screws containing bone morphogenetic protein-2 (BMP-2) in an osteoporotic rat model. Methods : Twenty-four female Wistar rat (250-300 g, 12 weeks of age) were randomized into four groups. Three groups underwent bilateral ovariectomy (OVX). Biodegradable screws with or without BMP-2 were inserted in the proximal tibia in two implantation groups. The extracted proximal metaphysis of the tibiae were scanned by exo-vivo micro-computed tomography. Evaluated parameters included bone mineral density (BMD), trabecular bone volume (BV/TV), trabecular number, trabecular thickness, and trabecular separation (Tb.Sp). The tibia samples were pathologically evaluated by staining with by Hematoxylin and Eosin, and trichrome. Results : Trabecular formation near screw insertion site was evident only in rats receiving BMP-2 screws. BMD and BV/TV significantly differed between controls and the OVX and OVX with screw groups. However, there were no significant differences between control and OVX with screw BMP groups. Tb.Sp significantly differed between control and OVX and OVX with screw groups (p<0.05), and between the OVX and OVX with screw BMP group (p<0.05), with no statistically significant difference between control and OVX with screw BMP groups. Over the 12 weeks after surgery, bone lamellae in direct contact with the screw developed more extensive and thicker trabecular bone around the implant in the OVX with screw BMP group compared to the OVX with screw group. Conclusion : Biodegradable screws containing BMP-2 improve nearby bone conditions and enhance ostoeintegration between the implant and the osteoporotic bone.

• Journal of the military operations research society of Korea
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• v.37 no.1
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• pp.119-128
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• 2011

This paper deals with a study on mission analysis considering the effectiveness measurement of UAV system operations. This mission analysis process is composed of 5 steps; (1) creation of a base model in MANA, (2) design of input parameter set using experiment design, (3) mapping input parameter set to the MANA scenario file, (4) data farming and model run in batch process, and (5) statistical analysis of the simulation result. In the result of this study, the effect of input parameter to the dependent parameter was shown to decrease in the order classification range, sweep width, height, speed, FOV(Field of view), and classification probability. The study also shows that the operational effectiveness of an improved scenario proposed can increase 10.2% from the base scenario.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12C
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• pp.1184-1193
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• 2006

Image interpolation has been widely used and studied in the various fields of image processing. There are many approaches of varying complexity and robustness. In this paper, a new distance weight is proposed for the conventional linear interpolation. In comparison with the conventional linear weight, the new distance weight uses a quadratic or cubic polynomial equation to reflect that the interpolated value should be influenced more by the value of closer pixels in an input image. In this paper, the new adaptive linear (NAL) interpolation, which considers patterns near the interpolated value, is also proposed. This algorithm requires a pattern weight, which is used to determine the ratio of reflection on local patterns, to obtain an interpolated image that exhibits better quality at various magnification factors (MF). In the computer simulation, not only did the NAL interpolation exhibit much lower computational complexity than conventional bicubic interpolation, it also improved peak signal-to-noise ratios (PSNR).

• Journal of Broadcast Engineering
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• v.12 no.5
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• pp.503-515
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• 2007

A new fast motion estimation algorithm is presented in this paper. The algorithm, named Enhanced Cross-Diamond Search (ECDS), is based on the Diamond Search (DS) algorithm. The DS algorithm, even though faster than the most well-known algorithms, was found not to be very robust in terms of objective and subjective qualities for several sequences and the algorithm searches unnecessary candidate blocks. We propose a novel ECDS algorithm using a small cross search as the initial step, and large/small DS patterns as subsequent steps for fast block motion estimation. Experimental results show that the ECDS is much more robust, provides a faster searching speed, and smaller distortions than other popular fast block-matching algorithms.