• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.43-51
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• 2008

In this paper, we are implemented low-power structure for Inter prediction, Intra prediction, Deblocking filter, Transform and Quantization blocks in H.264/AVC Encoder. The proposed Inter/Intra prediction blocks are shown 60.2% cell area reduction by adder reduction through Distributed Arithmetic, 44.3% add operation reduction using MUX for hardware share in Deblocking filter block. Furthermore we applied CSD and CSS process to reduce the cell area instead of multipliers that take a lot of area. The FPGA(Field Programmable Gate Array) and ARM Process based H.264/AVC encoder is implemented using proposed low power IPs. The proposed structure Platforms are implemented to interlock with FPGA and ARM processors. H.264/AVC Encoder implementation using Platforms shows that proposed low-power IPs can use H.264/AVC Encoder SoC effectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1380-1393
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• 2010

This paper presents a design, fabrication and the test results of planar active electronically scanned array(AESA) radar prototype for airborne fighter applications using transmit/receive(T/R) module hybrid technology. LIG Nex1 developed a AESA radar prototype to obtain key technologies for airborne fighter's radar. The AESA radar prototype consists of a radiating array, T/R modules, a RF manifold, distributed power supplies, beam controllers, compact receivers with ADC(Analog-to-Digital Converter), a liquid-cooling unit, and an appropriate structure. The AESA antenna has a 590 mm-diameter, active-element area capable of containing 536 T/R modules. Each module is located to provide a triangle grid with $14.7\;mm{\times}19.5\;mm$ spacing among T/R modules. The array dissipates 1,554 watts, with a DC input of 2,310 watts when operated at the maximum transmit duty factor. The AESA radar prototype was tested on near-field chamber and the results become equal in expected beam pattern, providing the accurate and flexible control of antenna beam steering and beam shaping.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.485-493
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• 2007

Introduction: Although several types of calcium-phosphate coumpound have been frequently applied to osseous defects at maxillofacial area for many years, there is a controversy about its efficiency on bone conductivity comprared to xenograft bone substitute. Alloplastic carbonapatite has been introduced to improve disadvantages of hydroxyapatite and to mimic natural bone containing carbon elements. However, a preclinical study about its efficiency of osteoconductivity has not been reported. This study was performed to evaluate the early osteoconductive potential of synthetic carbonapatite with multiple pores relative to anorganic bovine xenograft. Materials and methods: Total 5 beagle dogs were used for maxillary augmentation model. The control (anorganic bovine xenograft) and experimental groups (synthetic carbonapatite) were randomly distributed in the mouth split design. After bone graft, all animals were sacrificed 4 weeks after surgery. Histological specimens with Masson Trichrome staining were made and histomorphometrically analysed with image analyser. The statistical analysis was performed using paired t-test. Results: In both groups, all animals had no complications. The experimental group showed relatively much new bone formation around and along the bone substitutes, whereas it was clearly reduced in the control group. The ratios of new bone area to total area, to material area and to the residual area excluding materials were higher in the experimental group ($0.13{\pm}0.03,\;0.40{\pm}0.13,\;0.20{\pm}0.06$ respectively) than in the control group ($0.01{\pm}0.01,\;0.03{\pm}0.02,\;0.03{\pm}0.03$, respectively). And the differences between both groups were statistically significant (p<0.001, <0.01, <0.01, respectively), while the ratio of material area to total area in two groups was not significant. Conclusion: Carbonapatite showed a high osteoconductivity in the early stage of bone healing compared to bovine derived anorganic bone substitute. This study suggests that this bone materials can be applied as a reliable bone substitute in the clinical treatment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.4
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• pp.275-282
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• 2017

In this paper, using a pattern transformation triggered by deformation, we propose a porous structure that exhibits the characteristic of negative Poisson's ratio in both tension and compression. Due to the lack of torque for rotational motion of ligaments, the existing porous structure of circular holes shows positive Poisson's ratio under tension loading. Also, the porous structure of elliptic holes has a drawback of low durability due to stress concentration. Thus, we design curved ligaments to increase the rotational torque under tension and to alleviate the stress concentration such that strain energy is uniformly distributed in the whole structure. The developed structure possesses better stiffness and durability than the existing structures. It also exhibits the negative Poisson ratio in both compression and tension of 10% nominal strain. Through nonlinear finite element analysis, the performance of developed structure is compared with the existing structure of elliptic holes. The developed structure turns out to be significantly improved in terms of stiffness and durability.

• Journal of Industrial Convergence
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• v.18 no.2
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• pp.37-44
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• 2020

This paper of descriptive-correlative design determined the effects of health perception, need of exercise and self-efficacy on the frequency of exercise among diabetic patients. A total of 86 questionnaires were retrieved from these groups of diabetic patients, who regularly visits endocrinology clinics and accomplished voluntarily the major instrument distributed from two university hospitals in A city, during June to July, 2018. The result was a significant positive relationship that existed between health perception (r=.215, p=.043) and self-efficacy (r=.440, p<.001) with frequency of exercise respectively. Regression analysis revealed that the factor affecting the frequency of exercise is self efficacy (β=.440, p<.001) which illustrated to have a significant effect in the model's explanatory power at 18.4%(F=20.836, p<.001) results. This suggests that diabetic patients with a high positive health perception increase self-efficacy, their self-efficacy will help increase the frequency of exercise if further developed. Therefore, if an intervention program is developed to improve the health perception and self-efficacy education program for diabetics, it will help improve the frequency of exercise, namely diabetes management exercise.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.4
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• pp.345-352
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• 2008

Purpose: This study was performed to evaluate the stress distribution in the bone and the displacement distribution of the miniscrew under orthopedic force with two different types of miniplate design as skeletal anchorage for orthopedic treatment. Materials and methods: Finite element models were made for 6-hole miniplate (0.8mm in thickness), which were designed in two different shapes-one is curvilinear shaped (C plate, Jeil Medical Co., Korea) and another, Y shaped (Y plate), fixed with 3 pieces of miniscrew 2mm-diameter and 6mm-long respectively. A traction force of 4 N was applied in $0^{\circ}$, $30^{\circ}$ and $60^{\circ}$ to imaginary axis connecting two unfixed distalmost holes of the miniplate. Results: The maximum von Mises stress in the bone was much greater in the cortical portion rather than in the cancellous portion. C plate showed greater maximum von Mises stress in the cortical bone than Y plate. The maximum displacement of the miniscrew was greater in C plate than Y plate. The more increased the angle of the applied orthopedic force, the greater maximum von Mises stress in the bone and maximum displacement of the miniscrew. It was observed that in C plate, the von Mises stress in the bone and displacement of the miniscrew were distributed around the distalmost screw-fixed area. Conclusions: The results suggest that Y plate should have the advantage over C plate and in the placement of the miniplate, its imaginary axis should be placed as parallel as possible to the direction of orthopedic force to obtain its primary stability.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.187-191
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• 1994

A mixed forest community in Tokyusan was studied to determine the adequate plot area of tree stratum for investigating forest community structure. Nineteen nested plots were set up in the studied forest community, and species-area curve and performance curve were established. According to species-area curve, the minimum plot area where a given percentage increase in plot area produced less than the same percentage increase in number of species was 500$m^2$. The minimum plot area where a given percentage increase in plot area produced less than the half of the percentage increase in number of species was 1,000$m^2$. According to performance curve of the importance values of the major species, the minimum plot area where the importance value of the major species was distinguished from each other was 900$m^2$, and the minimum plot area was 500$m^2$ except for a big tree of Pinus densiflora distributed unexpectedly. According to performance curve of species diversity, the minimum plot area was 400$m^2$. Similarity indices between plot area above 900$m^2$ and total plot area were more than 90% and similarity indices between plot area above 400$m^2$ and total plot area were more than 85%. It may be as a conclusion that minimum plot area was generally about 500$m^2$ and in case of requiring more accuracy, minimum plot area was about 1,000$m^2$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.216-227
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• 2004

A new cavitating model by using bubble size distribution based on bubbles-mass has been proposed. Both liquid and vapor phases are treated with Eulerian framework as a mixture containing minute cavitating bubbles. In addition vapor phase consists of various sizes of vapor bubbles, which are distributed to classes based on their mass. The bubble number-density for each class was solved by considering the change of the bubble-mass due to phase change as well as generation of new bubbles due to heterogeneous nucleation. In this method, the bubble-mass is treated as an independent variable, and the other dependent variables are solved in spatial coordinates and bubble-mass coordinate. Firstly, we employed this method to calculate bubble nucleation and growth in stationary super-heated liquid nitrogen, and bubble collapse in stationary sub-cooled one. In the case of bubble growth in super-heated liquid, bubble number-density of the smallest class based on its mass is increased due to the nucleation. These new bubbles grow with time, and the bubbles shift to larger class. Therefore void fraction of each class is increased due to the growth in the whole class. On the other hand, in the case of bubble collapse in sub-cooled liquid, the existing bubbles are contracted, and then they shift to smaller class. It finally becomes extinct at the smallest one. Secondly, the present method is applied to a cavitating flow around NACA00l5 foil. Liquid nitrogen and liquid oxygen are employed as working fluids. Cavitation number, $\sigma$, is fixed at 0.15, inlet velocities are changed at 5, 10, 20 and 50m/s. Inlet temperatures are 90K in case of liquid nitrogen, and 90K and 1l0K in case of liquid oxygen. 110K of oxygen is corresponding to the 90K of nitrogen because of the same relative temperature to the critical one, $T_{r}$=$T/T_c^{+}$. Cavitating flow around the NACA0015 foils was properly analyzed by using bubble size distribution. Finally, the method is applied to a cavitating flow in an inducer of the LE-7A hydrogen turbo-pump. This inducer has 3 spiral foils. However, for simplicity, 2D calculation was carried out in an unrolled channel at 0.9R cross-section. The channel moves against the fluid at a peripheral velocity corresponding to the inducer revolutions. Total inlet pressure, $Pt_{in}$, is set at l00KPa, because cavitation is not generated at a design point, $Pt_{in}$=260KPa. The bubbles occur upstream of the foils and collapse between them. Cavitating flow in the inducer was successfully predicted by using the bubble size distribution.

• Journal of Korea Water Resources Association
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• v.35 no.2
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• pp.221-229
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• 2002

For the efficient design of baffled Powdered activated carbon(PAC) contractor, which has been widely used in water treatment plant(WTP) against the algae-related odor problems, a CFD(computational fluid dynamics) program was applied. In order to verify the performance of FLOW-3D program, the previously reported results of tracer tests from a pilot-scale PAC contractor(working volume of 288 liters) were compared to those from FLOW 3D. The results of FLOW-3D simulation were very similar to those from tracer tests conducted with the Pilot-scale PAC contactor. On the other hand, the hydrodynamic characteristics of baffled contractor in the P-WTP were simulated by using FLOW-3D. Simulation results on the distribution of PAC particles showed that there are some stagnant parts in the back side of baffles in which PAC Particles are not present. These stagnant parts might decrease the adsorption capacity of PAC particles. When the baffles were changed to maze-type intra-basin baffling, PAC particles were evenly distributed and the amount of stagnant parts reduced. In conclusion, it is anticipated that FLOW-3D simulation could be a viab1e tool for analyzing the hydrodynamic characteristics of structures used in drinking water treatment plant.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.65-73
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• 2012

Recently climate change and increase of surface runoff caused the urban flooding. Traditional way of dealing with urban flooding has been to increase the sewer capacity or construction of pumping stations, however, it is practically almost impossible because of time, money and traffic problems. Multipurpose DRMS (Decentralized Rainwater Management System) is a new paradigm proposed and recommended by NEMA (National Emergency Management Agency) for both flood control and water conservation. Suwon City has already enacted the ordinance on sound water cycle management by DRMS. In this study, a flood prone area in Suwon is selected and analysis of DRMS has been made using XP-SWMM for different scenarios of RT installation with same total rainwater tank volume and location. Installing one rainwater tank of 3,000$m^3$ can reduce the peak flow rate by 15.5%. Installing six rainwater tanks of 500$m^3$ volume in the area can reduce the peak flow rate by 28%. Three tanks which is concentrated in the middle region can reduce peak rate more than evenly distributed tanks. The method and results found from this study can be used for the design and performance prediction of DRMS at a flood prone area by supplementing the existing sewer system without increase of the sewer capacity.