• Composites Research
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• v.12 no.4
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• pp.42-54
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• 1999

FMLC(Fiber-Metal Laminate Composites) is a new structural material combining thin metal laminate with adhesive fiber prepreg, it nearly include all the advantage of metallic materials, for example: good plasticity, impact resistance, processibility, light weight and excellent fatigue properties. This research studied the optimum design of the FMLC subject to various loading conditions using genetic algorithm. The finite element method based on the shear deformation theory was used for the analysis of FMLC. Tasi-Hill failure criterion and Miser yield criterion were taken as fitness functions of the fiber prepreg and the metal laminate, respectively. The design variables were fiber orientation angles. In genetic algorithm, the tournament selection and the uniform crossover method were used. The elitist model was also used to be effective evolution strategy and the creeping random search method was adopted in order to approach a solution with high accuracy. Optimization results were given for various loading conditions and compared with CFRP(Carbon Fiber Reinforced Plastic). The results show that the FMLC is more excellent than the CFRP in point and uniform loading conditions and it is more stable to unexpected loading because the deviation of failure index is smaller than that of CFRP.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.364-371
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• 2017

TPMS is a vehicle electric system that measures the air pressure of a tire, and informs the driver of current tire states. The TPMS sensor typically uses unidirectional communication for small size, light weight, and low power. The transmission period of the sensor indicates the service quality of monitoring the tire. In order to determine the optimal transmission period, frame collision probability and the life time of the sensor should be analyzed. In this paper, collision probability model using Venn diagram is designed in low power TPMS with the normal and warning mode. And the life time and a collision probability were analyzed with the ratio(n) of the normal mode to warning mode transmission period. As a result, $T_{nP}=31sec$ and $T_{wP}=2.4sec$ at 5 years, and $T_{nP}=71sec$ and $T_{wP}=2.5sec$ at 7 years.

• Environmental Engineering Research
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• v.16 no.2
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• pp.81-90
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• 2011

Different weight percentages of Ag, Pt, and Au doped nano $TiO_2$ were synthesized using the acetic acid hydrolyzed sol-gel method. The crystallite phase, surface morphology combined with elemental composition and light absorption properties of the doped nano $TiO_2$ were comprehensively examined using X-ray diffraction (XRD), $N_2$ sorption analysis, transmission electron microscopic (TEM), energy dispersive X-ray, and DRS UV-vis analysis. The doping of noble metals stabilized the anatase phase, without conversion to rutile phase. The formation of gold nano particles in Au doped nano $TiO_2$ was confirmed from the XRD patterns for gold. The specific surface area was found to be in the range 50 to 85 $m^2$/g. TEM images confirmed the formation a hexagonal plate like morphology of nano $TiO_2$. The photocatalytic activity of doped nano $TiO_2$ was evaluated using 4-chlorophenol as the model pollutant. Au doped (0.5 wt %) nano $TiO_2$ was found to exhibit higher photocatalytic activity than the other noble metal doped nano $TiO_2$, pure nano $TiO_2$ and commercial $TiO_2$ (Degussa P-25). This enhanced photocatalytic activity was due to the cathodic influence of gold in suppressing the electron-hole recombination during the reaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.672-680
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• 2017

A solar photovoltaic system is composed of a module mounting structure, supporting trunk, and a control unit that supplies generated electrical power to an external power grid or a load. The efficiency of the system depends on the incident solar light, so the mounting structure is installed to face the sun. However, because the sun always moves, systems that track the sun have better efficiency than fixed systems. The structure experiences wind pressure, snow load, seismic load, and structure weight. The wind pressure has the most serious effect on the structure. The pressure was obtained using finite element method for various gaps between modules and angles between the panel and the ground. The wind pressure is lowest when the gap is zero, and it increases with the inclination angle. Based on the results, a mounting structure module was designed.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.3
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• pp.181-189
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• 2001

The software components of embedded control systems get extremely complex as they are designed into distributed systems get extremely complex as they are designed into distributed systems consisting of a large number of inexpensive microcontrollers interconnected by low-bandwidth real-time networks such as the controller area network (CAN). While recently emerging middleware technologies such as CORBA and DCOM address the complexity of distributed programming, they cannot be directly applied to distributed control system design due to their excessive resource demand and inadequate communication models. In this paper, we propose a CORBA-based middleware design for CAN-based distributed embedded control systems. Our design goal is to minimize its resource need and make it support group communication without losing the IDL (interface definition language) level compliance to the OMG standards. To achieve this, we develop a transport protocol on the CAN and a group communication scheme based on the well-known publisher/subscriber model. The protocol effectively realizes subject-based addressing and supports anonymous publisher/subscriber communication. We also customize the method invocation and message passing protocol, referred to as the general inter-ORB protocol (GIOP), of CORBA so that CORBA method invocations are efficiently serviced on a low-bandwidth network such as the CAN. This customization includes packed data encoding and variable-length integer encoding for compact representation of IDL data types. We have implemented our CORBA-based middleware on the mArx real-time operating system we have developed at Seoul National University. Our experiments clearly demonstrate that it is feasible to use CORBA in developing distributed embedded control systems possessing severe resource limitations. Our design clearly demonstrates that it is feasible to use a CORBA-based middleware in developing distributed embedded systems on real-time networks possessing severe resource limitations.

• Journal of Ocean Engineering and Technology
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• v.19 no.4 s.65
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• pp.28-34
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• 2005

In the study application of volcanic scoria concrete to artificial reefs is investigated. Volcanic scoria is a natural volcanic product that shows light weight, mil/i-porous, and far-infrared irradiation characteristics. The properties of volcanic scoria concrete using Jeju scoria aggregate are evaluated by conducting a comprehensive series of tests on strength and void ratio. It is concluded that the volcanic scoria concrete has the sufficient strength of 4MPa-13MPa and adequate void ratio of $12\%-35\%$ to be accepted as artificial reef concrete. The field experiments are performed through observation by scuba diver's at the Seogwipo coast. Porous specimen and plane concrete specimen are prepared for comparison purposes. Seasonal changes of soft coral on the two series of test specimens were have been observed from Apr. 9, 2004 to Mar. 18, 2005. The soft coral is well grown on the porous specimen however there are no significant changes on the conventional plain concrete specimen. Thus it is concluded that the volcanic scoria concrete is highly suitable as artificial reef concrete.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.5
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• pp.1063-1072
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• 2009

Membranous nephropathy(MN) is the most common cause of adult nephrotic syndrome worldwide. But treatment of MN is not defined. This study was to evaluate the effects of Lonicerae Flos Extract(LFE) on the MN induced by cBSA in mice. Mice were divided into 4 groups. The first group named for 'Normal' was injected with a saline solution. The second group named 'Control' treated with cBSA(10 mg/kg i.p) only. The third group named 'LFE-250', treated with cBSA(10 mg/kg i.p) and LFE(250 mg/kg, p.o). The fourth group named 'LFE-500'treated with cBSA(10 mg/kg i.p) and LFE(500 mg/kg, p.o). After cBSA and LFE treatment for 4 weeks, we measured change of body weight, 24hrs proteinuria, serum albumin, total cholesterol, triglyceride, BUN, creatinine, TNF-$\alpha$, IL-6, IL-$1{\beta}$, IL-10, IFN-$\gamma$, IgA, IgM and IgG levels. The morphologic changes of renal glomeruli were also observed with a light microscope. The levels of 24 hrs proteinuria, total cholesterol, IgG , IgM, IgA, IL-6 were significantly decreased in both LFE groups. The level of triglyceride, IL-$1{\beta}$ was significantly decreased in LFE-500 group. The level of Albumin was significantly increased in LFE-250 group. The level of TNF-$\alpha$, IFN-$\gamma$ were significantly decreased in LFE-250 group. The mRNA expression of IL-$1{\beta}$ in splenocytes was consideraly decreased in LFE-500 group. In histological findings of kidney tissue, thickening of GBM decreased in both LFE groups. This study shows that the LFE might be effective for treatment of MN. More clinical data and studies are to be done for efficient application.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.47-52
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• 2011

This paper collect sleep environment data of bedroom to sleeping, and analyzing the relationship between conditions with obtained data and sleep. We provide the optimal sleep environment of individual by extracting the simulation model based on it. The experiments was using temperature/humidity sensor(SHT11) and ambient light sensors(GL5507). For extraction of tossing and turning, we use difference image method in motion extraction from video. In addition, the information of weight can affect to sleep, it was entered such as ratio of fatigue, drinking, empty stomach. As a result, we are able to extract the optimal sleep environment. The future, we will try to improve to help to lead more pleasant daily life providing proper indoor environment changes depending on the situation even a partial of organic ubiquitous living environments such as eating, work ete. as well as certain sleep circumstances.

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.117-126
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• 2010

Experiment on flexural analysis of RC beams strengthened with composite material panel is presented. Recently, the strengthening of reinforced concrete structures using advanced fiber reinforced plastic (FRP) composites, and in particular the behavior of FRP-reinforced concrete structure is topic that has become very popular because of good corrosion resistance and easy for site handling due to their light weight. In this study, an efficient computational analysis using ABAQUS to predict the ultimate moment capacity of reinforced concrete beams strengthened with FRP is presented. Test parameters in this study are the shape of fiber arrangement (LT, DB, DBT) and the number of carbon fiber sheets (2ply, 3ply). When comparing with results of the analytical model, results of the experiments show similar values. Furthermore, reinforced concrete beam with FRP obtains improved effects for ultimate strength.

• The Journal of Korean Medicine
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• v.30 no.4
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• pp.93-107
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• 2009

Objective: Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults. However, there is not a satisfactory treatment for MN. This study aimed to evaluate the effect of Houttuyniae Herba Extract (HHE) on MN induced by cationic bovine serum albumin (cBSA). Methods: Mice were divided into 4 groups. The first group, Normal, was injected with saline. The second group, Control, was treated with cBSA (10mg/kg i.p) only. The third group, HHE-250, was treated with cBSA (10mg/kg i.p) and HHE (250mg/kg, p.o). The fourth group, HHE-500, was treated with cBSA (10mg/kg i.p) and HHE (500mg/kg, p.o). After treatment for 4 weeks, we measured change of body weight, 24 hrs proteinuria, serum albumin, total cholesterol, triglyceride, BUN, creatinine, IgA, IgM, IgG, TNF-${\alpha}$, IL-1${\beta}$ levels and the mRNA expression of IFN-${\gamma}$, IL-6, and IL-10. The morphologic changes of renal glomeruli were also observed with a light microscope and an electron microscope. Results: The levels of 24 hrs proteinuria and serum triglyceride, BUN, IgG, TNF-${\alpha}$, IL-1${\beta}$ significantly decreased in both HHE groups, while the level of serum albumin significantly increased in both HHE groups. The mRNA expression of IFN-${\gamma}$ and IL-6 in splenocytes considerably increased in both HHE groups. The mRNA expression of IL-10 in splenocytes considerably decreased in both HHE groups. In histological findings of kidney tissue, thickening of GBM decreased in both HHE groups. Conclusions: This study shows that HHE might be effective for treatment of acute stage MN. More clinical data and studies are to be done for efficient application.