• International Journal of Advanced Culture Technology
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• v.5 no.2
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• pp.90-97
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• 2017

The Internet of Things(IoT) market is expected to grow from 15.5billion to 75.4 billion by 2015-2025. As the number of IoT devices increases, the amount of data that is sent to the cloud is increasing. Today's Cloud Computing models are not suited to handle the vast amount of data generated by IoT devices. In this paper, we propose a Cooperation Coordinator System that reduces server load and improved real-time processing capability under specific circumstances by using Band-Cloud. The cooperation coordinator system dynamically forms the cloud when cooperation is needed between mobile devices located near. It is called Band-Cloud. Band-Cloud provides services entrusted by Central Cloud. This paper describes the proposed system and shows the cooperation process using the Android-based mobile devices and Wi-Fi Direct technology. Such a system can be applied to cases where real-time processing is required in a narrow area such as a hospital ward or a school classroom.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.120-124
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• 2010

Monometallic, bimetallic and trimetallic particles consisting of different weight compositions of Pt-Pd-Rh over pure alumina wash coats have been synthesized and their catalytic performance on methane conversion was studied from 150 to $600^{\circ}C$. Different catalyst formulations with variable Pt, Pd and Rh contents for bimetallic and trimetallic systems were tried and $Pt_{(1.5)}Rh_{(0.3)}/Al_2O_3$ and $Pt_{(1.0)}Pd_{(1.0)}Rh_{(0.3)}/Al_2O_3$ shows low $T_{50}$ and $T_{90}$ temperatures. Bimetallic and trimetallic particle synergism acts as three way catalysts and therefore, all the catalysts show 100% methane conversion. The effect of supports such as $ZrO_2$ and $TiO_2$ on methane combustion was investigated; from $T_{50}$ and $T_{90}$ results both $Al_2O_3$ and $ZrO_2$ are suitable supports for low temperature methane combustion.

• Structural Engineering and Mechanics
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• v.47 no.1
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• pp.75-98
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• 2013

This study focuses on shear strengthening performance of simply supported reinforced concrete (RC) T-beams bonded by glass fibre reinforced polymer (GFRP) strips in different configuration, orientations and transverse steel reinforcement in different spacing. Eighteen RC T-beams of 2.5 m span are tested. Nine beams are used as control beam. The stirrups are provided in three different spacing such as without stirrups and with stirrups at a spacing of 200 mm and 300 mm. Another nine beams are used as strengthened beams. GFRP strips are bonded in shear zone in U-shape and side shape with two types of orientation of the strip at $45^{\circ}$ and $90^{\circ}$ to the longitudinal axis of the beam for each type of stirrup spacing. The experimental result indicates that the beam strengthened with GFRP strips at $45^{\circ}$ orientation to the longitudinal axis of the beam are much more effective than $90^{\circ}$ orientation. Also as transverse steel increases, the effectiveness of the GFRP strips decreases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1064-1069
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• 2007

This paper proposes the highly miniaturized active $90^{\circ} power combiner for application to MMIC. Conventional passive $90^{\circ} power combiners can't be integrated on MMIC because of their very larger size. Therefore, the highly miniaturized $90^{\circ} power combiners are required for a development of highly integrated MMIC. For this paper, the highly miniaturized active $90^{\circ} power combiner employing InGaP/GaAs HBT was fabricated on GaAs substrate for application to highly integrated MMIC. A size of fabricated active $90^{\circ} power combiner was $2.42{\times}1.05$ mm, which was 2.2 % of conventional passive $90^{\circ} power combiner. The fabricated active $90^{\circ} power combiner showed a gain characteristic about 10 dB and a good phase-difference coupling characteristic of $-92.6^{\circ} than conventional passive $90^{\circ} power combiner at 2.4 GHz. The highly miniaturized active $90^{\circ} power combiner exhibited good RF performances comparable to conventional passive $90^{\circ} power combiners. This work is the first report of an active $90^{\circ} power combiner.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.147-155
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• 2009

The buckling and failure of filament wound thick composite cylinders under external hydrostatic pressure were investigated by the finite element analysis and test. ACOS, MSC.NASTRAN, and MSC.MARC were used for finite element analysis. T700 carbon-epoxy filament wound composite cylinders were fabricated to have winding angles of $[\pm30/90]_{FW}$, $[\pm45/90]_{FW}$, $[\pm60]_{FW}$, $[\pm60/90]_{FW}$, and tested to verify the finite element analysis. Among the softwares, ACOS predicted buckling load the best with about 1.7~14.3% deviation from test. Analysis and test shows cylinders do not recover the initial buckling pressure after buckling and directly lead to final failure.

• Journal of Gastric Cancer
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• v.12 no.4
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• pp.223-231
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• 2012

Purpose: Clinical staging of gastric cancer appears to be important more and more for tailored therapy. This study aimed to verify the accuracy of clinical T staging in a low-volume institute. Materials and Methods: We retrospectively reviewed prospectively collected data of gastric cancer patients who underwent resection. A total of 268 patients of gastric cancer were enrolled from March 2004 to June 2012. These demographics, tumor characteristics, and clinical stages were analyzed for identification of diagnostic value of clinical T staging. Results: The predictive values for pT1 of endoscopy and computed tomography were 90.0% and 89.4%, respectively. In detail, the predictive values of endoscopy for pT1a, pT1b, and pT2 or more were 87%, 58.5%, and 90.6%, respectively. The predictive values of computed tomography for pT1a, pT1b, and pT2 or more were 68.8%, 73.9%, and 84.4%, respectively. The factors leading to underestimation of pT2 or more lesions by gastroscopy were the middle third location, the size greater than 2 cm, and younger age. Those for overestimation of pT1 lesion by computed tomography were male, age more than 70 years, elevated type, and size greater than 3 cm. Conclusions: Diagnostic accuracy of early gastric cancer was 90%, which is comparable to those of high volume center. In patients with early gastric cancer, limited gastrectomy or minimal invasive surgery can be safely introduced at a low volume center also. However, the surgeon of low-volume institute should consider the accuracy of clinical staging before extending the indication of limited treatment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.579-587
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• 1998

In this study, fatigue behavior of the optical fiber sensor embedded in composite laminate was investigated. Static tensile and fatigue tests were performed for three types of laminated composite specimens with embedded optical fiber sensor in the neutral plane ; [0/sub 6//OF/0/sub 6/]/sub T/, [0/sub 2//90/sub 4//OF/90/sub 4//0/sub 2/]/sub T/ and [0/sub 3//90/sub 3//OF/90/sub 3//0/sub 3/]/sub T/. The fracture of the embedded optical fiber sensor was detected by the intensity drop off of laser signal transmitted through the optical fiber sensors embedded within laminated composite specimen. The maximum fatigue stress applied to laminated specimen was compared with the average tensile stress at which the fracture of the embedded optical fiber within the laminate occurred under static tensile loading. From the experiments, firstly it is observed that the decrease in the life of optical fiber sensors embedded within unidirectional-ply laminate by the fatigue loading is relatively small compared to that of cross-ply laminate. Secondly, the optical fiber embedded in unidirectional-ply laminate is fractured by the fatigue damage due to the growth of internal defects of optical fiber, however the optical fiber embedded in cross-ply laminate is fractured by the growth of transverse matrix crack.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.970-976
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• 2013

An evaluation of the organic matter removal efficiency showed high removal efficiencies of 91.1~96.3% and 91.4~97.5% for TCODcr and TBOD5, respectively, for 9hr or longer of HRT. However, the removal efficiencies decreased to 86.9~90.5% and 88.0~90.9%, respectively for 6hr of HRT. $NH_3$-N showed a high removal efficiency of 95% or higher for 9hr or longer of HRT. The total nitrogen removal efficiency was 67.6~76.7% for 9~12hr of HRT, and it decreased to 50% for 6hr of HRT, which seems to be due to the insufficient carbon source required for denitrification. The T-P removal efficiency was 32% on average. To comply with the legal standards, a chemical phosphorus removal process is needed after the reactor.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.441-447
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• 2014

The purpose of this study was to explore differences of spinal stabilization muscle strength between groups classified by BMI for industrial workers. Fifty subjects participated in this study were divided to obesity group(BMI over $25kg/m^2$) and non obesity group(BMI under $25kg/m^2$). Independent t-test was applied for analysis. The results showed the following. There were significant differences in $0^{\circ}$ Forward on sagittal plane, in both $90^{\circ}$ Left, $90^{\circ}$ Right on coronal plane, in $45^{\circ}$ Left Tilt, $45^{\circ}$ Right Tilt on diagonal plane between groups. Last, There were significant differences in an amount of soft lean muscle and an amount of skeletal muscle between groups. These results shows that spinal stabilization muscle strength program for the obese should be considered in sagittal plane, coronal plane, and diagonal plane.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.243-250
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• 2020

The purpose of this study is to find out the possibility of applying microwave-hypochlorous acid leaching to effectively leaching Au in hydrothermal minerals on board. The comparative leaching experiment were confirmed that the leaching rate of Au with(T1)/with out(T2) of microwave nitric acid leaching. In addition, the leaching rate of Au on the conventional leaching by mechanical agitation(T3) and microwave leaching was compared. The result of microwave nitric acid leaching(solid-liquid ratio; 10%, leaching temperature; 90 ℃, leaching time; 20 min) confined that the metal leaching rate was high in the order of As>Pb>Cu>Fe>Zn, and the content of Au in the leaching residue was increased from 33.77 g/ton to 60.02 g/ton. As a result of the comparative leaching experiment using a chloride solvent, the dissolution rate of Au was high in the order of T1(61.10%)>T3(53.30%)>T2(17.30%). Therefore, chloride, which can be manufactured using seawater and that can be recycled by collecting chlorine gas generated in the leaching process, is expected to be an optimal solvent for Au leaching. In addition, the application of microwaves is believed to be effective in terms of time, efficiency and energy.