• Journal of the Society of Naval Architects of Korea
• /
• v.36 no.2
• /
• pp.40-49
• /
• 1999

A Finite Volume Method for the two-dimensional incompressible, two-fluids Navies-Stokes equation and level-set scheme are used to analyse the interface of two fluids, free-surface flow. The numerical characteristics and the applicability of level-set scheme are brief1y investigated and appraised by solving oscillating small surface wave in a water tank and dam break problems. In the numerical results, a method for improving the convergence of the solution is presented.

• Journal of Korean Home Economics Education Association
• /
• v.2 no.1
• /
• pp.101-110
• /
• 1990

The purpose of this study is to survey the learner’s need achievement, interest and practical level of the learning objectives according to the teacher’s teaching method in home economics of middle school(Dietary Life Unit), to examine the differences according to the local situation, and to get some information to improve the teaching method. This study surveyed the eight units of dietary life with 459 students in the rural community (224 students) and Seoul(235 Students). The collected data were analyzed by T-test, F-test. To sum up this study are as follows: 1. When the need, achievement, interest and practical level of unit “food”are compared the students of seoul with those of rural community, the student of Seoul show high in “The use of Processed Foodstuffs” and low in “Cooking the Processed Foodstuffs.”The student of rural community show in “A kind of Cooking Method”and low in “Environment and Food Life”. 2. The need, achievement, interest, practical level of the whole unit in rural community is higher than those is Seoul. 3. According to teaching method, comparison Seoul with rural community is revealed as follows. Seoul region is revealed significance to discovery learning in “Cooking Foodstuffs(The achievement and interest level) and ”Environment and Food Life”(interest level). Rural community is revealed significance to discussion learning in “The constituent and Food Life”(The need level, interest level). Rural community is revealed significance to explanation learning in “Environment and Food Life”(The achievement level).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.8 no.2
• /
• pp.140-146
• /
• 2015

We have studied an efficient threshold level for desired target detection in radar system in the paper. A desired target searching detection method detects desired target according to changing for false alarm probability. This time, false alarm probability is close relation to threshold level. Low threshold level can improve detection for desired target, but detect noise signal. Therefor, This method is not good one. In this paper, we propose efficient threshold level method in order to estimation for desired target. Through simulation, we are analysis and performance to compare general method with proposal method. We show that proposed method is more good proof than general method.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.2
• /
• pp.161-174
• /
• 2014

The methodology report '2006 IPCC Guidelines for National Greenhouse Gas Inventories' shows higher tier method can be a good practice, which uses country-specific or plant-specific data when calculating greenhouse gas emissions by country. We review the methodology report to present principles of using plant-level data and also examine examples of using plant-level data in chemical and metal industry in 20 countries for the purpose of quality improvement of national greenhouse gas inventories. We propose that Korea consider utilizing plant-level data, as reported according to 'Greenhouse gas and Energy Target Management Scheme', in the following order as a preference. First, the data can be utilized for quality control of Korea's own parameters, when Tier 2 method is adopted and bottom-up approach is not applicable. Second, both plant-level data and IPCC default data can be used together, combining Tier 1 method with Tier 3 method. Third, we can also use acquired plant-level data and country specific parameters, combining Tier 2 method with Tier 3 method. Fourth, if the plant-level data involves all categories of emissions and the data is proven to be representative, we can apply Tier 3 method. In this case, we still need to examine the data to check its reliability by a consistent framework, including appropriate quality control.

• Journal of Korean Society for Quality Management
• /
• v.45 no.2
• /
• pp.293-306
• /
• 2017

Purpose: In this study, an optimal design level of influencing factors on semiconductor polishing process was determined to minimize flexion of both sides on wafers. Methods: First, significant interactions are determined by the stepwise regression method. ANOVA analysis on SN ratio and mean of dependent variable are performed to draw mean adjustment factors. In addition, the optimal levels of mean adjustment factors are decided by comparing means of each level of mean adjustment factors. Results: As a result of ANOVA, a mean adjustment factor was determined as a width of formed flexion on the plate. The mean of the difference has the nearest to 0 in the case when the width of formed flexion has level 2 (4mm). Conclusion: Optimal design levels of semiconductor polishing process are determined as follows; (i) load applied to the wafer carrier has a level 1 (3psi), (ii) load applied to the wafer has a level 1(3psi), (iii) the amount of slurry supplied during polishing has a level 3 (300 co/min), (iv) the width of formed flexion on the plate has level 2 (4mm).

• Journal of Korean Society of Transportation
• /
• v.18 no.3
• /
• pp.101-112
• /
• 2000

The Purpose of this Paper was to revise the method of USHCM and to establish new method for level of service analysis on two-lane rural highways. For this Purpose, total delay rate was selected as new MOE for level of service, replacing the present Percent time delay. This result showed that total delay rate was more effective for considering the effects of traffic flows, auxiliary lane, and vertical tirade. The application of total delay rate could resolve the Problems in the USHCM method, such as too wide ranges for level of service D and E, and the use of different Procedures for level of service analysis of general terrain segment and specific grade Procedures. The research results are as follows First, a new method for level of service analysis on two-lane rural highways was developed using the total delay rate. Second, a new classification for level of service was developed and a consistent method applicable for general terrain segment and specific tirade Procedures was developed. Third, the desired speed on two-lane rural highways was determined as 85km/h.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.2
• /
• pp.105-110
• /
• 2008

This paper presents a control method to maintain stable mold level for unsteady bulging in high speed casting. The stabilizing mold level is an important factor to get high quality products. But, for various reasons, there are several disturbance factors which make mold level unstable. Bulging is one of disturbance factors and considered for the current stage of study. We design a disturbance observer to attenuate the effect of bulging which is periodic mold level disturbance. Since the period of bulging varies with the casting speed, the parameters of disturbance observer are changed by the casting speed. Simulation is illustrated to demonstrate stable performance of the proposed method in comparison with a previous method in a variable operating frequency.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.72.2-72.2
• /
• 2019

The hydroxyl radical (OH) sky emission lines arise from the Earth's mesosphere, and they serve as a major source of the sky background in the infrared. With IGRINS, the observed line strength show non-negligible variation even within a few minutes of time scale, making its subtraction difficult. Toward the aim better sky subtraction in the IGRINS pipeline, we present 1) improved identification of sky lines in H and K band and 2) improved method of subtracting sky background. Using the recent line list of Brooke et al. (2015), we have detected ~500 OH doublets from upper vibrational level between 2 and 9 and maximum upper J level of 25. In particular, we found that a significant fraction of unidentified lines reported by Oliva et al. (2015) are indeed OH lines resulting from transitions between different F levels. With the extended line identification, we present an improved method of sky subtraction. The method, based on the method of Noll et al. (2014), empirically accounts non-LTE level population of OH molecules.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.4
• /
• pp.586-593
• /
• 2010

In this paper, I have proposed that the 1st and 2nd AC-DC transformation methods using multi-level pulsating currents and selection switches. Through making the rectified voltage of the proposed AC-DC translation which is similar to reference voltage by selecting from multi-level pulsating currents, the proposed translation has dramatically reduced the ripple voltage. I have compared the performance of the DC voltage, the ripple voltage and the peak to peak voltage of the proposed method with the conventional method. The simulation results show that the proposed 2nd method has the better performance than the 1st method in the point of average DC voltage drop and peak to peak voltage increase.

• Journal of Elementary Mathematics Education in Korea
• /
• v.13 no.2
• /
• pp.193-210
• /
• 2009

This research were to develop and apply an educational program for 6th grade students in mathematics by using level orientated teaching method and to make an analysis of their effects on students' mathematics learning achievements and mathematical disposition. Those purposes is following: First, we develop the level orientated teaching method that fits to the low level and high level students and analyze the effect on students' mathematics learning achievements. Second, we analyze the effect on students' mathematical disposition by using level orientated teaching method. The biggest problem of applying level orientated teaching method is that all the groups should do the meaningful activity while just one group is on process. So we tried to keep the proposition that level orientated teaching method should be helpful to both high and low level students. The duration of the research was about 8 weeks from march 2 to may 22 and the level orientated mathematics program consists in lesson 1 "a fraction and a decimal" to lesson 3 "The range of numbers". The results of this study are as follows : First, there was significant effect to the students, develop level orientated mathematics program and using that program. Second, there was an affirmative effect to the students about mathematical disposition using level orientated mathematics program. To sum up conclusion of this study, the level orientated mathematics program has an affirmative effect on mathematics learning achievements and mathematical disposition. We expect further research about level orientated teaching method and use effective level orientated teaching method widely.