• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.199-203
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• 2009

The purpose of this research is to investigate how the indoor temperature has influence on occupants' attention abilities as a basis of productivity. To achieve the purpose, the experiment in chamber was conducted. In the experiment, temperature was controlled according to two levels ($20^{\circ}C$ or $23^{\circ}C$) and other of factors were controlled uniformly. Subjects were exposed to those two different thermal environments. Each participant was asked to mark their answers on the state of attention measurement sheets (FAIR and Trail making test), in two conditions. Total 60 times of experiments were conducted. The main results are as follows. First, subjects showed the better attention abilities in relation to Q score at $20^{\circ}C$. But on the other hand attention abilities in relation to C score were better at $23^{\circ}C$. Second, subjects showed the better attention abilities in relation to concentrate on one task at $20^{\circ}C$.

• Journal of Mechanical Science and Technology
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• v.14 no.2
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• pp.177-187
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• 2000

Dilution is an important factor which influences the properties of clad layer. In this paper the change of dilution during laser cladding and the control of dilution are simulated by a finite element method. The adaptive mesh method is adopted for the time-dependent finite element method computation so that the shape of melt pool can be well represented. The situation of the width control of melt pool is also simulated, which indicates that the dilution can be controlled if the width of melt pool is controlled. Computational results indicate that if a line energy (input energy per unit distance) remains constant the dilution will increase with time, especially at the beginning. Simulation results show that it is possible to control dilution in a certain range if the line energy decreases with time. Experiment of Nd: YAG laser cladding with wire feeding is performed. Experiment results coincide well with the FEM results.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.11 no.1
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• pp.157-166
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• 2007

Background: The change in the respiratory pattern has an influence on the change in the autonomic nervous system, which in turn has an influence on the EGG to measure a gastric activity. However, the study on the influence on the EGG parameters by respiratory control and on the correlation between the HRV and EGG through respiratory control has not been perform yet. Objective: It is to perform a series of experiments to find out how the EGG parameters are influenced by the controlled respiration and what correlation there may exist between the EGG and HRV to measure the change in the autonomic nervous system after controlled respiration. Methods: 1st Experiment: During a 15minutes' voluntary respiration, HRV was measured, and it was measured again during another 15 minutes' controlled respiration. 2nd Experiment: After an eight hours' fast, EGG was measured for a period of 30 minutes, and then after another 15 minutes' voluntary respiration, a test-meal was offered for 10 minutes and again EGG was measured. The next day, after an 8 hour's fast, EGG was measured for 30 minutes, and after a 15 minutes' controlled respiration and offered with a test-meal for 10 minutes and then EGG was measured again for 30 minutes. Results: 1. It was observed in all the channels that the power ratio increased more after controlled respiration than after voluntary respiration. No statistical significance, however, could be observed. 2. Through controlled respiration, the HF of HRV and the power ratio of EGG Channel 4 was negatively correlated, while the LF/HF of HRV and the power ratio of EGG channel 1 & 4 was positive correlated. Such correlations as mentioned above, however, could not be observed in HRV & EGG through voluntary respiration. Conclusions: 1. It was concluded that the increase in the power of gastric contractile after controlled respiration is bigger than the increase in the power of gastric contractile after voluntary respiration. 2. It was concluded that the gastric contractile power and sympathetic activity through controlled respiration was negatively correlated, while the gastric contractile power and parasympathetic activity through controlled respiration was positively correlated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.5
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• pp.397-401
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• 2003

This experiment was conducted to know the characteristics of kernel growth as affected by various temperature regimes during grain filling using the varieties Hwaseongbyeo, Ilpumbyeo and Chucheongbyeo. The rice plants tested were grown in the natural condition at 1/5000a Wagner pots until flowering. After flowering, the rice plants were moved to controlled temperature conditions in a phytotron. The minimum/maximum daily temperature in the phytotron was controlled by 12/18, 15/21, 18/24, 21/27, and 24/$30^{\circ}C$, respectively. The grain weights were measured every three days after treatment. The mean daily kernel growth rate during active grain filling period showed different responses among varieties under various temperature regimes. The kernel growth rate of Chucheongbyeo was seriously reduced as temperature regimes were decreased. However, that of Ilpumbyeo was not influenced so critically. Ilpumbyeo showed some advantages in grain filling under low temperature regimes compared to Chucheongbyeo. The lag phase in grain filling of Chucheongbyeo was the longest among tested varieties, followed by Hwaseongbyeo under daily mean temperature regime of $15^{\circ}C$. Kernel weight of Ilpumbyeo increased fast in early grain filling phase under low temperature. This characteristic may be favorable for grain filling in temperate zone where the daily mean temperature is drastically dropped during grain filling period. Regression analysis with kernel growth rate and temperature showed the estimated critical low temperature for grain filling among varieties were $9^{\circ}C$, $12^{\circ}C$, $13^{\circ}C$ in Ilpumbyeo, Hwaseongbyeo and Chucheongbyeo, respectively. Under moderate temperature the duration of grain filling of Ilpumbyeo was longer than that of Chucheongbyeo. However, Under low temperature that of Ilpumbyeo was more favorable than Chucheongbyeo.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.79-80
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• 2016

A discrete time domain analysis for the duty-cycle-controlled buck LED driver is performed in this paper. Based on the analysis, the design guidelines are derived. Experimental results are presented to confirm the design.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.142-145
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• 1998

The purpose of this study is to estimate lateral formwork pressure controlled by super-workable fresh concrete using prototype structrues such as, tall wall, retaining wall, and beam quantitativly. As a result of this experiment, a function which can be used to design a formwork system and to predict formwork pressure curve is formulated.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.466-470
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• 1991

In this paper, full bridge inverter with IGBT is proposed. By Controlling phase angle difference between 2 arms, PWM controlled high frequency link inverter has VVVF capability. For the simplicity, flexibility and compactness of control circuit, 16 bit single chip microcontroller 8797 BH is used and its characteristic is examined through experiment.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.68-69
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• 2011

Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between the two conduction modes. Especially, the time delay can provide an accurate LED current for the peak current controlled (PCC) buck converter with a wide input voltage. Experimental results are presented for the PCC buck LED driver with constant-frequency controller.

• Journal of Information Technology Services
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• v.14 no.1
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• pp.129-143
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• 2015

This study has two goals. The first goal is to investigate whether worked examples are effective in the ill-defined domain with on-line learning and the second goal is to find out which components (conceptual or procedural knowledge) of worked examples are effective factor at the given learning environment. We carried out three experiments in which Korean undergraduate or graduate students were working in three or four conditions of worked examples (CWE, PWE, CPWE, or the control group). While experiment 1 conducted in on-line learning environment did not find any effect and difference among groups and also any logical reason for those results, experiment 2 conducted in completely controlled laboratory setting with less knowledgeable students showed the clear difference among groups by the order CPWE, PWE, and CWE. Experiment 3 in which highly knowledgeable and motivated students were presented the same materials in more controlled on-line learning environment indicated the difference among groups by the order CWE, CPWE, and PWE. The results were discussed within the framework of cognitive load theory.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.13-18
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• 1998

In the flue curing process, the wet bulb temperature is usually controlled at a constant level. To improve the quality of flue cured leaves, we studied the effect of the cyclic change of wet bulb temperature at the yellowing stage of flue curing on physical properties of cured leaves. The wet bulb temperature was automatically controlled between preset high (38℃) and low point (35℃) every one hour cyclically. As a result, the acceleration of the increase in the physical properties of cured leaves were observed. The leaves cured by this method were more or less orange in color, better bodied, and less brittle compared with the leaves produced by conventional curing. However, the leaves cured by this method had a little sharpness and harshness. As to the physical properties, there was decreased in occurrence of flat leaves than that of conventional ones. On the other hand, in case of cyclic curing method, increase of price per kg reached to 2-3% compared with those of conventional ones.