• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.229-235
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• 2007

The KTX, which have opened the revenue service in April 2004, is operating in Kyoung-Bu high-speed line and electrified conventional Ho-Nam line, and the more the electrification are enlarged, the more the requirement of operating of high speed train would be increased. In this paper, the result of test run and evaluation on the suitability of operating high speed train in electrified conventional line between Dae-jeon and East Dae-gu was reviewed. Evaluation and analysis was executed in specific categories, such as operation & running performance of the train considering vibration characteristics based on UIC 518, ride comfort and current collection, and response sensitivity of ATS device for signalling from track facility. The result of this running test was evaluated and considered as a good practice for revenue operation of high speed train in electrified conventional line between Dae-jeon and Dae-gu.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.10-13
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• 2003

6.6㎸rms/200Arms DC reactor type superconducting fault current limiter (SFCL) has been developed. This paper deals with the manufacture and short-circuit test of the SFCL. DC reactor was the HTS solenoid coil whose inductance was 84mH. AC/DC power converter was performed as the dual-mode operation. The short-term run(1 sec) and short-circuit test of this SFCL was performed successfully. The experimental results have a similar tendency to the simulation results. In short-circuit test, at 2 cycles after the fault, fault current limitation rate was about 30％.

• 한국농공학회지
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• 제26권4호
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• pp.52-65
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• 1984

In general precise estimation of hourly of daily distribution of the long-term run-off should be very important in a design of source of irrigation. However, there have not been a satisfying method for forecasting of stationar'y long-term run-off in Korea. Solving this problem, this study introduces unit-hydrograph method frequently used in short-term run-off analysis into the long-term run-off analysis, of which model basin was selected to be Sumgin-river catchment area. In the estimation of effective rainfall, conventional method neglects the Soil moisture condition of catchment area, but in this study, the initial discharge (qb) occurred just before rising phase of the hydrograph was selected as the index of a basin soil moisture condition and then introduced as 3rd variable in the analysis of the reationship between cumulative rainfall and cumulative loss of rainfall, which built a new type of separation method of effective rainfall. In next step, in order to normalize significant potential error included in hydrological data, especially in vast catchment area, Snyder's correlation method was applied. A key to solution in this study is multiple correlation method or multiple regressional analysis, which is primarily based on the method of least squres and which is solved by the form of systems of linear equations. And for verification of the change of characteristics of unit hydrograph according to the variation of a various kind of hydrological charateristics (for example, precipitation, tree cover, soil condition, etc),seasonal unit hydrograph models of dry season(autumn, winter), semi-dry season (spring), rainy season (summer) were made respectively. The results obtained in this study were summarized as follows; 1.During the test period of 1966-1971, effective rainfall was estimated for the total 114 run-off hydrograph. From this estimation results, relative error of estimation to the ovservation value was 6%, -which is mush smaller than 12% of the error of conventional method. 2.During the test period, daily distribution of long-term run-off discharge was estimated by the unit hydrograph model. From this estimation results, relative error of estimation by the application of standard unit hydrograph model was 12%. When estimating by each seasonal unit bydrograph model, the relative error was 14% during dry season 10% during semi-dry season and 7% during rainy season, which is much smaller than 37% of conventional method. Summing up the analysis results obtained above, it is convinced that qb-index method of this study for the estimation of effective rainfall be preciser than any other method developed before. Because even recently no method has been developed for the estimation of daily distribution of long-term run-off dicharge, therefore estimation value by unit hydrograph model was only compared with that due to kaziyama method which estimates monthly run-off discharge. However this method due to this study turns out to have high accuracy. If specially mentioned from the results of this study, there is no need to use each seasonal unit hydrograph model separately except the case of semi-dry season. The author hopes to analyze the latter case in future sudies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.848-850
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• 2002

Single phase induction motor is directly used usual source, it can be a source of an appliance such as mechanical fan, refrigerator, washing machine, etc. Especially capacitor-run single phase induction motor is suitable to make more inexpensive and high efficient products because it is more high efficiency, and good to start than other single phase induction motors. Generally, voltage and current of capacitor-run single phase induction motor transfer to the part of positive phase and negative phase based on two motor theory. In this paper, we simulate the torque characteristics to capacitance variation from single phase induction motor's equivalent circuit. Through the test using the real motor, we compare and investigate the maximum torque of run state related with capacitance and the adequacy of the converted model.

• 인지과학
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• 제3권2호
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• pp.249-270
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• 1992

본 논문은 입력 문자에 대한 특징 추출을 위하여 최대 길이 투영(MRLP:Maximum Run Length Project)방법을 제안한다. 제안된 최대길이 투영 방법은 잡음에 강하며 필요한 정보를 가능한 정확하고 효율적으로 추출하는데 유용하다.한글문자는 그 양이 방대하고 그 구조가 복잡하며 몬자들 사이에 밀접한 유사성이 있다.따라서 본 논문에서는 추출된 특징들에 대한 퍼지추론을 적용하여 유형 분류율의 향상을 도모하였다.사용 빈도수가 높은 인쇄체 한글 문자 917자에 대하여 실험한 결과 98.58%의 분류율을 얻었다.

• 동아시아경상학회지
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• 제4권4호
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• pp.21-23
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• 2016

There are so much oil and gas reserves in Iran. Therefore extraction from these reserves and sell extracted oil and gas in international markets causes to high oil income for Iran. Especially in some years which oil price increases, our oil income was too high. In this paper, we want to reveal that, high oil income is not cause to rise of nonoil export. For this aim, we use from data of 1971-2013 and with Johansen co-integration test and Error Correction Model (ECM) extract short run and long run relations. Results of estimation reveal that in Iran high oil income is not cause to many non oil exports in long run and short run. Therefore, we should allocate oil income to import industrial machines and reallocate them to agriculture and industrial sectors which causes to raise national production which will cause to high non oil export. Then, in this condition, our needy exchanges are provided from non oil export and our dependence to oil income will be declined.

• 대한조선학회지
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• 제8권1호
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• pp.29-40
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• 1971

In order to study the problem on form factor of hull form, towing test of a full ship model was carried out for different initial trims under both full and half load conditions. The results were fully discussed on the mutual relations among initial trim, mean sinkage and trim change in run, and form factor. There exists optimum initial trim in regard to form factor. Mean sinkage and trim change in run can be expressed in a uninominal approximation in the form of $k_i{\cdot}{F_n}^{2.2}$. The coefficients of this approxmation are related linearly with the initial trim. Form factor changes according to Froude number. It is considered that the trim change in run is a main reason of the fact.

• 대한토목학회논문집
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• 제34권3호
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• pp.723-728
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• 2014

세굴방지를 위하여 설치하는 해안구조물의 쇄파효과를 검증하기 위하여 수리조파실험이 실시된다. 하지만 수리조파실험을 실시하기 위해서 사용되는 실험 장치와 해안구조물의 제작에 많은 비용과 시간이 소요된다. 수치해석모델과 수리조파실험의 해석결과를 비교하여 검증하면, 수치모델을 활용하여 쇄파효과를 예측할 수 있고 실험 장치와 해안구조물 제작에 소요되는 비용과 시간을 절약할 수 있다. 본 연구에서는 다면체 사석 구조물을 대상으로 수치해석결과와 수리조파실험 결과의 처오름 및 처내림 높이 비교분석을 수행하였고 해석적 모의 조파실험 모델링 기법을 검증하였다. 또한, 사용한 수치해석 접근 방법을 활용하여 사석의 부피비와 마찰면적을 변화시켜 쇄파효과를 예측하였다.

• Restorative Dentistry and Endodontics
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• 제47권3호
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• pp.32.1-32.11
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• 2022

Objectives: This study aimed to evaluate the influence of inorganic composition and filler particle morphology on the mechanical properties of different self-adhesive resin cements (SARCs). Materials and Methods: Three SARCs including RelyX Unicem-2 (RUN), Maxcem Elite (MAX), and Calibra Universal (CAL) were tested. Rectangular bar-shaped specimens were prepared for flexural strength (FS) and flexural modulus (FM) and determined by a 3-point bending test. The Knoop microhardness (KHN) and top/bottom microhardness ratio (%KHN) were conducted on the top and bottom faces of disc-shaped samples. Sorption (Wsp) and solubility (Wsl) were evaluated after 24 hours of water immersion. Filler morphology was analyzed by scanning electron microscopy and X-ray energy dispersive spectroscopy (EDS). FS, FM, %KHN, Wsp, Wsl, and EDS results were submitted to 1-way analysis of variance and Tukey's post-hoc test, and KHN also to paired t-test (α = 0.05). Results: SARC-CAL presented the highest FS value, and SARC-RUN presented the highest FM. SARC-MAX and RUN showed the lowest Wsp and Wsl values. KHN values decreased from top to bottom and the SARCs did not differ statistically. Also, all resin cements presented carbon, aluminum, and silica in their composition. SARC-MAX and RUN showed irregular and splintered particles while CAL presented small and regular size particles. Conclusions: A higher mechanical strength can be achieved by a reduced spread in grit size and the filler morphology can influence the KHN, as well as photoinitiators in the composition. Wsp and Wsl can be correlated with ions diffusion of inorganic particles.

• 동아시아경상학회지
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• 제6권3호
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• pp.24-36
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• 2018

Purpose - From establishing China-Japan diplomatic relations in 1972, the relations between two states has improved a lot, from which makes the government and the people reap much benefit. Owing to this reason, this paper aims at exploiting the impact of exchange rate volatility of RMB on China's foreign direct investment to Japan. Research design and methodology - The quarterly time series data from 2003 to 2016 will be employed to conduct an empirical analysis under the vector error correction model. Meanwhile, a menu of estimated methods such the Johansen co-integration test and the Granger Causality test will be also used to explore the impact of exchange rate volatility of RMB on China's foreign direct investment to Japan. Results - The empirical analysis results exhibit that the real exchange rate has a positive effect on China's foreign direct investment to Japan in the long run. Conversely, the real exchange rate volatility of RMB, the trade openness and the real GDP have a negative effect on China's foreign direct investment to Japan in the long run. However, in the short run, the China's foreign direct investment to Japan, the real exchange rate, the trade openness and the real GDP in period have a negative effect on China's foreign direct investment to Japan in period. Oppositely, the real exchange rate volatility of RMB in period has a positive effect on China's foreign direct investment to Japan in period. Conclusions - From the empirical evidences in this paper provided, it can be concluded that an increase in the exchange rate volatility of RMB can result in a decrease in the China's foreign direct investment to Japan in the long run. However, an increase in the exchange rate volatility of RMB can lead to an increase in the China's foreign direct investment to Japan in the short run. Therefore, the China's government should have a best control of the real exchange rate volatility of RMB so as to improve China's foreign direct investment to Japan.