• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.74-80
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• 2011

In this study, a variety of welding experiments were carried out to optimize root-pass welding process using GMA process. Based on the experimental results, optimal welding conditions were selected after analyzing correlation between welding parameters and back-bead geometry. Then, effectiveness of empirical models developed was compared and analyzed, and optimized empirical models were finally developed for predicting back-bead by analyzing the main effect of each factor which affects back-bead geometry and their influence on interaction. Also, functions proper for expressing the surface of back-bead were selected using diverse quadratic functions, and back-bead geometry was visualized using empirical models developed and quadratic functions.

• Journal of Life Science
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• v.11 no.2
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• pp.111-120
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• 2001

The pathological aspects of purified ricin from the seeds of the castor oil plant, Ricinus communis, were examined, using light and transmission electron microscopy. ICR mice were exposed to ricin by peritoneal injection with 100 ng/1 $m\ell$ PBS(pH 7.0) mouse and histological observations on the liver, spleen, thymus, lung and heart were carried out at intervals up to 48 h after exposures. All the organs examined were damaged by ricin. Among the organs, the spleen and thymus; immune organs were the most sensitive to ricin, whereas the effect delayed in the liver, lung and heart. Furthermore, the immune cells in each organ were the most sensitive to ricin. Accordingly, the effect of ricin on the organs seems to be affected by the immune cells existed in each organ, In each organ, the immune cells showed apoptotic changes, while the capillary endothelial and parenchymal cells showed necrotic changes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.4
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• pp.113-122
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• 2004

A new diagnosis method for FPGA interconnects is developed. The proposed method diagnoses all the fault types for FPGA interconnects. It is also applied to all the modem FPGA devices like Xilinx Virtex FPGAS. Most of all, it takes shorter time to diagnose all the faults than previous diagnosis methods.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.247-251
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• 2015

In this study, electroglottographic spectral tilt (EST) was investigated for characterization of vocal cords vibration. EST was analyzed from the power spectrum of electroglottographic signals by dividing frequency analysis range as full range (0~4 octave), low range (0~2 octave), and high range (2~4 octave). EST of all ranges in female were greater than those in male. In female and male groups, EST of high range was higher than that of low range. This result suggests that EST has at least two components and dividing frequency range in analysis of EST is effective for investigating characteristics of vocal cords vibration.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.269-272
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• 2003

A low phase noise frequency synthesizer at X-Band which employs the subharmonic injection locking was designed and tested. The frequency synthesizer consists of two oscillators - master and slave : A 1.75GHz master oscillator made of PLL synthesizer produces 6th harmonic at 10.5GHz, which excites the following 10.5GHz slave oscillator. The realized frequency synthesizer has a 4.5dBm of output power, and a phase noise of -108dBc/Hz at the 100kHz offset frequency.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.11-21
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• 2017

In this study, bacterial growth was assessed by flow cytometry analysis of fluorescent probes-stained bacteria. Flow cytometry has many advantages of rapid analytical time, a low standard deviation, and highly sensitive detection of live and Dead E.coli over colony forming assay. When untreated bacteria were stained by using Thiazole Orange (TO) and Propidium Iodide (PI), double staining had a short analytical time as compared with that of single staining while its error rate was similar to that of single staining. Through double staining experiments, it was determined that optimal concentrations for TO and PI staining were 420 nM and $9.6{\mu}M$, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.311-316
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• 2007

This paper proposes the algorithm which estimates moment of the inertia and friction coefficient of friction for high performance speed control of electric motor. The proposed algorithm finds the moment of inertia and friction coefficient of friction by observing the speed error signal generated by the speed observer and using Recursive Least-Mean-Square method(RLS). By feedbacking the estimated inertia and estimated coefficient of friction to speed controller and full order speed observer, then the errors of the inertia and coefficient of friction and speed due to the inaccurate initial value are decreased. Inertia and coefficient of friction converge to the actual value within several times of speed changing. Simulation and actual experiment results are given to demonstrate the effectiveness of the proposed parameter estimator.

• Review of KIISC
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• v.19 no.1
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• pp.103-114
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• 2009

SNS (Social Network Service) 사이트는 사용자의 개인정보를 비롯하여 친구 정보, 설치된 응용정보 등으로 구성되는 아이덴티티를 친구 관계를 맺고 있는 다른 사용자에게 제공하고 있다. 따라서 SNS를 통해 공유되는 아이덴티티는 개방과 공유를 중심으로 하는 웹2.0 환경에서 어떻게 관리되고 운용되느냐에 따라 SNS 사용자들에게 이득이 되거나 피해로 다가올 수 있다. 본 고에서는 앞으로 사용이 증가할 것으로 예상되는 SNS 서비스에서 웹 2.0의 아이덴티티를 공유함으로써 사용자의 편리성과 업무 효율성을 제고할 수 있는 대표적인 서비스 시나리오에 대해 연구하고 구축된 Mockup SNS 사이트에서 구현한 사례를 제시한다. 그리고 사용자의 아이덴티티 이용이 아이덴티티 소유자에 의해 통제될 수 있는 지원체계 마련의 필요성과 프라이버시 보호 측면에서의 고려사항에 대해 논의한다.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.4
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• pp.125-138
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• 2012

Health care that is considered to be one of the major factors for the quality of life is nowadays receiving a great deal of attention, and thus there is a growing need in Korea to identify the efficiency of national medical service and enhance the competitiveness. Although there exist studies on the medical service efficiency about general hospitals and local hospitals, they mostly deal with the efficiency problems from a domestic and regional perspective. In response, this paper analyzes the competitive efficiency of national medical service with respect to 16 OECD countries, by exploiting Data Envelopment Analysis (DEA) and Malmquist Productivity Index (MPI). Building on the DEA and MPI analysis results, this paper identifies the competitive position of Korean national medical service and suggests implications for the medical service improvement.

• Journal of Environmental Science International
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• v.27 no.3
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• pp.227-231
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• 2018

We studied the warming effect induced by Photovoltaic(PV) power plants in rural areas during summer daytime using a simple analytical urban meteorological model. This analysis was based on observed meteorological elements and the capacity of the PV power plant was 10 MWp. The major axis length of the PV power plant was assumed to be 1km. Data of the necessary meteorological elements were obtained from a special meteorological observation campaign established for a over a PV power plant. We assumed that the wind flowed along the major axis of the PV power plant(1 km). As a result, the air temperature on the downwind side of the PV power plant was estimated to invrease by about $0.47^{\circ}C$.