• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.131-136
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• 2017

In this study, we design a controller that regulates the water leveling system which suffers from the disturbance. A number of control techniques have been reported which can reduce the amplitude of disturbance. But due to input-delay, these methods do not perform as expected. To overcome the problem, this paper introduces a filter and proposes a proportional and integral (PI) controller that combined with the filter (modifed PI controller). Moreover, we combine the controller with disturbance observer (DOB) that can estimate and eliminate disturbance. The proposed controller and combined the controller with DOB are tested using MATLAB.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.10
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• pp.1900-1907
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• 1992

This paper presents the vibration mode, natural frequencies and amplitudes of the circular plate due to the changes of the boundary conditions by varying free arc angles. The vibration mode, amplitudes and natural frequencies of the circular plate are obtained by time-average holographic interferometry and laser doppler vibrometer. The vibration modes of the circular plate with the mixed boundary conditions are found from the 1st mode to the 4th mode. The curve shapes of the natural frequency ratios obtained from this study are in a good agreement with other results obtained by numerical analysis. The displacement curves obtained from time average holographic interferometry and laser doppler vibrometer agree well in case of large amplitude, but show a little difference in case of small amplitude.

• Journal of The Korean Association For Science Education
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• v.36 no.3
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• pp.361-369
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• 2016

In this study, we investigated the characteristics of group discussion and classroom discussion in the scientific modeling of the particulate model of matter. 7th graders in Seoul participated in this study. We implemented science instructions based on the GEM cycle of scientific modeling. We analyzed the differences between group discussion and classroom discussion in three steps: exploring thoughts, comparing thoughts, and drawing conclusions. We also looked into the level of argumentations of the students in the modeling activities. The analysis of the results indicated that students generated a group model by extracting commonalities from each model of their group members, and then they evaluated and modified the group model by comparing the differences among the models in classroom discussion. The main step involved in group discussion was 'exploring thoughts', whereas in classroom discussion it was 'comparing thoughts'. Although the levels of argumentation among the students were generally low, most students participated with enthusiasm, as they expressed their interest and had positive perception in the modeling activities. As a result, the modeling activities were found to have positive influences on concept development. Some suggestions to implement the modeling activities in science teaching effectively were discussed.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.555-559
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• 2001

This research was conducted to estimate the chlorophyll contents of chrysanthemum leaves using SPAD-502 chlorophyll meter under different photoperiod and light intensity. Measurements were done at every third leaf intervals starting from the top of the stem to the bottom at harvest time. SPAD value was highest at 10 hours of photoperiods, followed by 13 and 16 hours of photoperiods. In particular, under short day condition, SPAD value was highest in the young leaves below the flower bud and decreased down the leaf profile. Under long day condition, SPAD value reached maximum at leaves between $15-27^{th}$ from the top and decreased to the minimum immediately below the flower bud (youngest leaf). These results may indicate that the younger leaves become strong source of supporting flowers in reproductive stage, while the younger leaves serve as sinks and older leaves support their development in vegetative stage. Changes of SPAD value at different levels of irradiance showed that highest SPAD value were observed at high irradiance and decreased with decreasing irradiance.

• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.76-82
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• 2002

This study investigated the effects of assigning cognitive roles, a method that may promote verbal interaction in knowledge-building processes, in small-group discussion for science concept learning. Two classes (62 students) of 7th-graders respectively received a concept learning instruction through small-group discussion with assigned cognitive roles (CR) asking to explain and contradict one's idea and to synthesize and conciliate group's idea, and a concept learning instruction through small-group discussion with no specific assigned roles (NSR), for 9 class periods. After the instructions, the tests of achievement, conceptions, the perceptions on science learning environments, and the perceptions toward small-group discussion were administered. ANCOVA results revealed that low-achievers in the NSR group performed significantly better than those in the CR group. Similar tendency was also found in the scores of the conceptions test. Two groups did not differ significantly in the perceptions on science learning environments and toward small-group discussion.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.51-59
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• 2009

This paper presents the design of continuous-time sigma-delta modulator for acoustic sensor. The feedforward structure without summing block is used to reduce power consumption of sigma-delta modulator. A high-linearity active-RC filter is used to improve resolution of sigma-delta modulator. Excess loop delay problem in conventional continuous-time sigma-delta modulators is solved by our proposed architecture. A low power, high resolution fourth-order continuous-time sigma-delta modulator with 1-bit quantization was realized in a 0.13-${\mu}m$ 1-Poly 8-metal CMOS technology, with a core area of $0.58\;mm^2$. Simulation results show that the modulator achieves 91.3-dB SNR over a 25-kHz signal bandwidth with an oversampling ratio of 64, while dissipating $290{\mu}W$ from a 3.3-V supply.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.72-78
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• 2003

In this study, the effects of grouping by extraversion and introversion in POE learning applied to elementary science class on students' achievement, the perception of learning environment and the attitude toward science instruction were investigated. Ninety-five 5th graders were assigned to the control group and the experimental groups, and taught about acid and base for 9 class hours. In the experimental groups, the homogeneous small group was composed of four introverts or four extroverts, and the heterogeneous small group was composed of two introverts and two extroverts. Two-way ANCOVA results revealed that the homogeneous group performed better than the control group in the application subtest of the achievement test. Significant difference in learning difficulty was found between the heterogeneous group and the control group. In the attitude toward science class, significant interaction effect was found between the instruction and the extraversion/introversion.

• 대한상한금궤의학회지
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• v.11 no.1
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• pp.35-46
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• 2019

Objective : The purpose of this study was to report the improvements of patients with globus pharyngeus treated with herbal medication from Shanghanlun. Methods : Each patient was diagnosed with Greater-yang disease 29th provision of Shanghanlun, and Gamchogungang-tang was used to treat. The result was evaluated by Glasgow-Edinburgh Throat Scale(GETS). Results : The GETS score decreased from 23 to 4 after 40 days of administration in case 1 and from 31 to 1 after 15 days of administration in case 2. Conclusions : Globus pharyngeus improved in each case. This case report suggests that '急' based on the 29th provision of Shanghanlun, can be a direct psychological cause of globus pharyngeus.

• 대한상한금궤의학회지
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• v.12 no.1
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• pp.183-198
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• 2020

Objective: The purpose of this study was to report improvement in patients with autism spectrum disorder (ASD) treated with herbal medication described in Shanghanlun. Methods: The patient was diagnosed with Lesser Yin disease based on the 315^th provision of Shanghanlun, and Baektonggajeodamjup-tang was used for treatment. The result was evaluated using the Korean-Childhood Autism Rating Scale (K-CARS). Results: The K-CARS score decreased from 32 to 15 after 7 months of treatment. Conclusions: Lesser Yin disease 315^th provision of Shanghanlun may be a provision describing ASD; in addition, Baektonggajeodamjup-tang may be an effective treatment for ASD.

• 대한상한금궤의학회지
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• v.13 no.1
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• pp.155-164
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• 2021

Objective: This study aimed to report the improvement of a patient with nummular eczema treated with Hoeyeok-tang based on Shanghanlun provisions. Methods: According to the disease pattern identification diagnostic system (DPIDS) based on the Shanghanlun provisions, the patient was diagnosed with lesser yin disease according to the 324^th provision. The patient was treated with Hoeyeok-tang for 90 days. The severity of pruritus decreased, and changes in symptoms were estimated by a visual analog scale, Scoring Atopic Dermatitis Index and the Validated Investigator Global Assessment for Atopic Dermatitis. Results: The patient's symptoms were improved. The severity of pruritus decreased and they recovered from abrasions. Conclusions: This study suggests that the 324^th provision of Shanghanlun refer directly to nummular eczema.