• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.857-860
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• 2006

It is important to diminish noise source of an electric motor used in appliances. We studied on the noise reduction of BLDC motor to drive a fan. Especially, this study was focused on detent torque caused by interaction between a permanent magnet of rotor and groove in stator. This source and rotating system brought about a resonance. This paper showed that the higher harmonic component of this torque had a main factor to lessen noise. So, we had designed new magnets with shape like a peanut and pseudo-sinusoidal flux density for low-noise BLDC motor in refrigerator.

• Journal of the Optical Society of Korea
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• 제3권2호
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• pp.80-85
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• 1999

We propose and demonstrate a new scheme for suppression of output distortion in an open-loop gyroscope employing an erbium-doped fiber amplifier/source (FAS). In addition to the main modulation for the rotation rate measurement, a small auxiliary modulation at a different frequency is used to extract an error signal, which is necessary for keeping the quasi-dc component of the feedback signal power at a constant level for varying rotation rate. By active tracking of the optimum modulation condition using this two-frequency modulation scheme, we obtain stable gyro output with suppressed distortion as well as stable FAS characteristics. We also calculate the distortion in the gyro response due to the feedback effect, from which we estimate the FAS gyro output distortion due to the residual ac feedback effect when the dc feedback effect is removed by the proposed scheme. The measured residual deviation agrees reasonably with the estimation.

• 산업경영시스템학회지
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• 제30권3호
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• pp.127-134
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• 2007

Predicting fatigue life of rubber components is an important issue in design procedure for industrial trucks to assure the durability and reliability. Main considerations in designing rubber components against fatigue failure are the compounding technology, shape design, and manufacturing process. Among them the rubber compounding technology is one of the most critical factor to determine more than 50% of component's quality. This paper presents how to improve the durability and reliability of industrial rubber mount during its design, development and prototype testing. The data presented illustrates explicitly the prediction of reliability growth in the product development cycle. The application of these techniques is a part of the product assurance function that plays an important role in rubber components reliability improvement.

• 설비공학논문집
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• 제16권9호
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• pp.804-810
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• 2004

This paper reports the characteristics of the three dimensional turbulent flow by numerical method in the 180 degree bends with increasing cross-sectional area. Calculated pressure and velocity, Reynolds stress distributions are compared to the experimental data. Turbulence model employed are low Reynolds number $textsc{k}$-$\varepsilon$ model and algebraic stress model(ASM). The results show that the main vortex generated from the inlet part of the bend maintained to outlet of the bend and vortices are continually developed at the inner wall region. The distribution of turbulent kinetic energy along the bend are increase up to 120$^{\circ}$ because of increment of cross-sectional area. Secondary flow strength of the flow is lower about 60% than that of square duct flow.

• Journal of Ginseng Research
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• 제16권2호
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• pp.105-110
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• 1992

Polysaccharide contents in Panax ginseng roots were evaluated by a spectrophotometry, utilizing the complex formation of ginseng polysaccharide with alcian blue dye in 50 mM ammonium biphos-phate, pH 4.2. The polysaccharide content in red ginseng was about three times higher than that in fresh ginseng when both were extracted with water, and increased about two times when red ginseng was extracted with an alkaline solution. The determination of polysaccharide in various parts of ginseng revealed that main roots contained the component more than fine roots. Fresh ginseng sections stained by the dye showed polysaccharide mainly was found in cortex and combium but not in epidermis.

• Journal of Ginseng Research
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• 제16권3호
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• pp.217-221
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• 1992

Total polysaccharide contents in Panax ginseng roots were evaluated by a spectrophotometry, utilizing the complex formation of ginseng polysaccharide with alcian blue dye in 50 mM ammonium biphosphate, pH 4.2. The total polysaccharide content in red ginseng was about three times higher than that in fresh ginseng when both were extracted with water, and was increased about two times when red ginseng was extracted with an alkaline solution. The determination of total polysaccharide in various parts of ginseng revealed that main roots contained the component more than fine roots. Fresh ginseng sections stained by the dye showed polysaccharide mainly found in cortex and cambium but not in epidermis. Pattern-analysis on total and acidic polysaccharides from fresh and red ginsengs exhibited that the chemical compositions of the polysaccharides extracted from both ginsengs quite differed from each other.

• 동력기계공학회지
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• 제14권6호
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• pp.61-66
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• 2010

Engineering asset management (EAM) requires the accurate assessment of current and the prediction of future asset health condition. Suitable mathematical models that are capable of predicting time-to-failure and the probability of failure in future time are essential. In general reliability models, lifetime of component and system is estimated using failure time data. This paper deals with the reliability assessment of elevators using life of main components. Especially this work is concerned with the stochastic nature of life of elevator components. First, we investigate the Weibull statistical analysis of lifetime data for the components. The final goal is to establish the mathematical model for reliability assessment. This work provides more perspectives to future research in the fields of reliability and maintainability.

• 동력기계공학회지
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• 제22권1호
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• pp.87-93
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• 2018

Specimens were machined out from hot-rolled AZ31 magnesium alloy, and deformed at 623K with rolling reduction of 30%. After hot rolling, specimens were annealed at various range of temperature and time. In this study, static recrystallization was occurred during heat treatment, however, variation of main component and intensity of texture was not revealed. The results of microstructure observation, damping capacity test and dislocation mechanism indicated that increasing of damping capacity was caused by grain growth. It means that grain size is effective factor to damping capacity.

• 한국CDE학회논문집
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• 제12권4호
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• pp.274-282
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• 2007

In this paper, a method of constructing a rectangular net from unorganized point cloud data is presented. In the method an implicit surface that fits the given point data is generated by using principal component analysis(PCA) and adaptive domain decomposition method(ADDM). Then a complete and quality rectangular net can be obtained by extracting voxel data from the implicit surface and projecting exterior faces of extracted voxels onto the implicit surface. The main advantage of the proposed method is that a quality rectangular net can be extracted from randomly scattered 3D points only without any further information. Furthermore the results of this works can be used to obtain many useful information including a slicing data, a solid STL model and a NURBS surface model in many areas involved in treatment of large amount of point data by proper processing of implicit surface and rectangular net generated previously.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.603-606
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• 2015

The post-production of smart farming defines the stage that the final products are delivered from producer to consumers via market on ICT network. It deals with the process of product packaging and distribution from producer to consumer with marketing strategy. This focus on reference model for post-production service including specialization, centralization of product delivery, and just-in-time delivery, and marketing system on the network. It defines a significant function component on post-production stage. The producer plays a significant role in economy being one of the main contributors to the many customers. This articles suggest the effective product distribution service which requires delivering the right product, in the right quantity, in the right condition, to the right place, at the right time, for the right cost, and encompassing global marketing based on ICT network, will be provided[1].