• Journal of Welding and Joining
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• v.23 no.1
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• pp.48-54
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• 2005

Laser keyhole welding is investigated using a three-dimensional Gaussian heat source, and the heat source parameters such as the keyhole depth, welding efficiency and power density distribution factor are determined in a systematic way. For partial penetration, the keyhole depth is same as the penetration and is predicted using the experimental data. The welding efficiency is calculated using the ray-tracing method and the power density distribution factor is determined from the bead shape. Full penetration is classified into the transition, normal and excessive modes depending on the degree of keyhole opening. Thermal analysis of the bead-on-plate welds is conducted using the Gaussian heat source, and the calculated weld geometries show reasonably good agreements with the experimental results.

• Journal of IKEEE
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• v.15 no.2
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• pp.129-133
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• 2011

A spread spectrum clock generation is an efficient way to reduce electro-magnetic interference (EMI) radiation in modern mixed signal chip systems. The proposed circuit generates the spread spectrum clock by directly injecting the modulation voltage into the voltage-controlled oscillator (VCO) current source for SATA II. The resulting 33KHz modulation profile has a Hersey-Kiss shape with a rounded peak. The chip has been fabricated using $0.18{\mu}m$ CMOS process and test results show that the proposed circuit achieves 0.509% (5090ppm) down spreading at 1.5GHz and peak power reduction of 10dB. The active chip area is 0.36mm ${\times}$ 0.49mm and the chip consumes 30mW power at 1.5GHz.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.54-62
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• 2013

A numerical analysis is performed to evaluate mass flow balance in the heat exchanger for the dehumidifier. To improve the mass flow balance for maximum heat transfer performance, inlet, outlet and baffle are changed. Mass flow balance is evaluated by non-uniformity of flow which is the same concept with the standard deviation. Usually, there will occur many paths between the inlet and the outlet, however, it will follow shortest and low resistance ways. The uniform distribution of flow is numerically analyzed for several types of heat exchangers. Making the shortest way between the inlet and the outlet is most important factor. Two types of heat exchangers are installed in the dehumidifier and 4 cases of Type A heat exchangers and 3 cases of Type B heat exchangers are evaluated and optimized. The result of this research is applied to design heat exchanger for commercial dehumidifiers.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.895-905
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• 2014

Recently the trade show is a massive marketing effort of a particular industry and introduces new products to potential customers, as well as the ability to elevate the brand's image and corporate identity. It is increasing its importance as a venue of communication. In these changes, the exhibition is required to have the emotional approach to enhance the dynamic and creative image of companies. Therefore, the product itself as well as the importance of various visual contents of the exhibition is increasing positive effect of the image and marketing on their products. In this sense, this study analyzes video contents of the exhibition that was held in Amsterdam, the Netherlands, Europe's largest display show 'ISE (Integrated Systems Europe)' in 2013, focusing on the domestic company, Samsung, LG Electronics and other four foreign companies. The analysis is based on the Herbert Zettl's applied media aesthetics related to the video contents, through which we can find the way to the development of exhibition video contents making for Trade show.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.15-26
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• 1997

There were a dramatic change in technical aspect in Korean detergent industry for past 5${\sim}$6 years. we, detergent industries, have been trying to find out a new way of production and better goods on environment as well as men to decrease domestic wastes and water pollution. In addition, increasing expense for transportation, storage and displaying give us another difficulties. Compact detergents are best method to solve this problems. Detergent ingredients, formulations and process were concentrated to the development of compact detergents. Now, I'll introduce about the recent trends in technical aspect and near future's prospects in Korean detergent industry.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.1
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• pp.34-40
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• 2006

Many producers put sampling inspection policy into the way of their convenience. Examples of the convenience are irregular lot size and too small sample size. Because they don't use a standard sampling inspection policy, they can not guarantee the quality level of their products. In this study, we developed a user-centered design program which can calculate the AOQL of their products to their buyers in the case of irregular lot size and too small sample size. Also this program propose a linear inspection cost by Hald's model.

• Korean Journal of Acupuncture
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• v.25 no.4
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• pp.147-166
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• 2008

Objective : This study is achieved to know the way that we can use metabolomics for the scientific research of Korean medicine. Results : We elucidate that metabolomics can be contributed to four ways for objectification of Korean medicine 1. Diagnosis of BeunJungLonChi(辯證論治). 2. Application toward Personalized medicine. 3. Quantification of Herbal medicine. 4. Evaluation of efficacy/safety for Korean medicine formulation Conclusion : Metabolomics opens up a new opportunity to reinvestigate Korean medicine from holistic perspective. Furthermore, Metabolomics is expected to provide effective method in research of acupuncture and meridian.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.759-762
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• 2012

This paper is for EPC(Evolved Packet Core) network to share the load balance by IMSI(International Mobile Subscriber Identity) prefix in MME(Mobility Management Entity). For the telecommunication, it needs to choose the anchoring gateway to use the specific gateway to avoid the traffic load to support the efficient telecommunication service. We propose the way to choose the effective gateway to avoid the traffic load in order for good qualify service. We compare the load between the gateways which are the general gateway and the specific gateway used by proposed concept.

• KIEE International Transactions on Power Engineering
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• v.11A no.4
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• pp.21-26
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• 2001

As competition is introduced in the electricity supply industry, congestion becomes a more important issue. Congestion in a transmission network occurs due to an operating condition that causes limit violations on the transmission capacities. Congestion leads to inefficient use of the system, or causes additional costs (Congestion cost). One way to reduce this inefficiency or congestion cost is to control the transmission flow through the installation of UPFC (Unified Power Flow Controller). This paper also deals with an optimal siting of the UPFC for reducing congestion cost by using shadow prices. A performance index for an optimal siting is defined as a combination of line flow sensitivities and shadow prices. The proposed algorithm is applied to the sample system with a condition, which is concerning the quadratic cost functions. Test results show that the siting of the UPFC is optimal to minimize the congestion cost by the proposed algorithm.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.325-331
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• 2015

Skin is exposed to sunlight or artificial indoor light on a daily. The reached solar light on the earth surface consist of 50% visible light and 45% infrared (IR) except for ultra violet (UV). The negative effects of UV including UVB and UVA have been steadily investigated within the last decades. However, little is known about the effects of visible or IR light. In this study, we irradiated human dermal fibroblasts using light emitting diode (LED) to investigate the optimal parameter for enhancing cell growth and collagen synthesis. We found that red of 630 nm and green of 520 nm enhance the cell proliferation, but irradiation with purple and blue light exerts toxic effects. To examine the response of irradiation time and light intensity on the fibroblasts, cells were exposed to red or green light with intensities from 0.05 to $0.75mW/cm^2$. Procollagen secretion was increased of 1.4 fold by 10 min irradiation, while 30 min treatment decreased the collagen synthesis of dermal fibroblasts. Treatment with red of $0.3mW/cm^2$ and green of 0.15 and $0.3mW/cm^2$ resulted in enhancement of collagen mRNA. Lastly, we investigated the combinatorial effect of red and green light on dermal fibroblasts. The sequential irradiation of red and green light is an efficient way for the purpose of the increase in the number of fibroblasts than single light treatment. On the other hand, the exposure of red light alone was more effective method for enhancing of collagen secretion. Our study showed that specific light parameters accelerated cell proliferation, gene expression and collagen secretion on human dermal fibroblasts. In conclusion, we demonstrate that light exposure with specific parameter has beneficial effects on the function of dermal fibroblasts, and suggests the possibility of its cosmetically and clinical application.