• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2087-2092
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• 2005

Using disturbance observer (DOB) is effective in enhancing the performance of dynamic system in the presence of disturbances. Recently the definition of disturbance has been expanded to modeling uncertainty including parameter variation, internal disturbance. Various structures of DOB have been proposed to improve sensitivity of system for better disturbance rejection performance. However in the case of improvement of sensitivity function, it tends to bring poor transient response due to cross-coupling and phase lag. Furthermore it could be very sensitive to measurement noise due to increased peak of complementary sensitivity function. In this paper, a dual disturbance observer (Dual-DOB) is proposed to reduce the effect of such cross-coupling. It is possible for us to improve the sensitivity function with additional external DOB with hardly affecting complementary sensitivity function. Thus it is able to have robustness against measurement noise. Since we are able to design DOBs of internal and external loop independently, we could prevent transient response quality from degrading while improving the sensitivity function. The proposed Dual-DOB is applied to a commercial optical disk drive tracking servo system. The experimental result shows that the Dual-DOB is an effective method in rejecting the disturbance as well as improving the tracking performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.127-132
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• 2017

In this paper, we propose a controller gain based on model based design and implement the two-wheel inverted pendulum type robot using NXT Lego and RobotC language. Two-wheel inverted pendulum robot consists of NXT mindstorm, servo DC motor with encoder, gyro sensor, and accelerometer sensor. We measurement wheel angle using bulit-in encoder and calculate wheel angle speed using moving average method. Gyro measures body angular velocity and accelerometer measures body pitch angle. We calculate body angle with complementary filter using gyro and accelerometer sensor. The control gain is a weighted value for wheel angle, wheel angular velocity, body pitch angle, and body pich angular velocity, respectively. We experiment and observe the effect of two-wheel inverted pendulum with respect to change of control gains.

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.463-465
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• 2003

Four protostane-type triterpenes, alisol B 23-acetate (1a), alisol C 23-acetate (2a), alisol B(3a), and alisol A 24-acetate (4a), were isolated from the rhizome of Alismatis plantago-aquatica L. var. orientale Samuelson (Alismataceae) and eleven protostane derivatives (compounds 1-11) were obtained by selective modification from alisol B 23-acetate (1a). These compounds were investigated for their anti-complement activity against the classical pathway of the complement system. Alisol B (3a) and alisol A 24-acetate (4a) exhibited anti-complement activity with $IC_{50} values of 150 and 130 \mu$ M. Among the synthetic derivatives, the tetrahydroxylated protostane triterpene (9) showed moderate inhibitory activity with $IC_{50} value of 97.1 \mu$ M. Introduction of an aldehyde group at C-23 (10; $IC_{50} value, 47.7 \mu$ M) showed the most potent inhibitory effect on the complement system in vitro.

• The Mathematical Education
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• v.57 no.4
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• pp.371-391
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• 2018

The purpose of this study is to analyze manifestation examples and effects of group creativity in mathematical modeling and to discuss teaching and learning methods for group creativity. The following two points were examined from the theoretical background. First, we examined the possibility of group activity in mathematical modeling. Second, we examined the meaning and characteristics of group creativity. Six students in the second grade of high school participated in this study in two groups of three each. Mathematical modeling task was "What are your own strategies to prevent or cope with blackouts?". Unit of analysis was the observed types of interaction at each stage of mathematical modeling. Especially, it was confirmed that group creativity can be developed through repetitive occurrences of mutually complementary, conflict-based, metacognitive interactions. The conclusion is as follows. First, examples of mutually complementary interaction, conflict-based interaction, and metacognitive interaction were observed in the real-world inquiry and the factor-finding stage, the simplification stage, and the mathematical model derivation stage, respectively. And the positive effect of group creativity on mathematical modeling were confirmed. Second, example of non interaction was observed, and it was confirmed that there were limitations on students' interaction object and interaction participation, and teacher's failure on appropriate intervention. Third, as teaching learning methods for group creativity, we proposed students' role play and teachers' questioning in the direction of promoting interaction.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.118-124
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• 2020

An analytical method was developed for hypoxia-inducible factor (HIF) stabilizers based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) sample preparation and liquid chromatography-high resolution mass spectrometry analysis. HIF stabilizers potentially enhance the performance of athletes, and hence, they have been prohibited. However, the analysis of urinary HIF stabilizers is not easy owing to their unique structure and characteristics. Hence, we developed the QuEChERS preparation technique for a complementary method and optimized the pH, volume of extraction solvent, and number of extractions. We found that double extraction with 1% of formic acid in acetonitrile provided the highest recovery of HIF stabilizers. Moreover, the composition of the mobile phase was also optimized for better separation of molidustat and IOX4. The developed method was validated in terms of its precision, detection limit, matrix effect, and recovery for ISO accreditation. To the best of our knowledge, this is the first demonstration of the application of the QuEChERS method, which is suitable as a complementary analytical method, in antidoping.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1591-1594
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• 2006

In this work, we fabricated efficient white organic light emitting device (WOLED) by the stack of complementary fluorescent dye-doped layers, Effect of dye-doping ratio and thickness of each layers on WOLED efficiency and emission spectrum was investigated. Moreover, out-coupling efficiency enhancement using microlens array was analyzed for bottom and top-emitting device architecture, leading to higher light extraction properties.

• Vacuum Magazine
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• v.5 no.2
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• pp.18-22
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• 2018

wo dimensional (2D) van der Waals (vdW) nanosheet semiconductors have recently attracted much attention from researchers because of their potentials as active device materials toward future nano-electronics and -optoelectronics. This review mainly focuses on the features and applications of state-of-the-art vdW 2D material devices which use transition metal dichalcogenides, graphene, hexagonal boron nitride (h-BN), and black phosphorous: field effect transistors (FETs), complementary metal oxide semiconductor (CMOS) inverters, Schottky diode, and PN diode. In a closing remark, important remaining issues of 2D vdW devices are also introduced as requests for future electronics and photonics applications.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.1006-1010
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• 1997

The nature and analysis methods of complicated decay profiles found in forced Rayleigh scattering (FRS) have been investigated for the probe diffusion of methyl yellow in 2-propanol. The complementary shifted and ground state grating effect, which is known to be the origin of non-single exponential decays, was analyzed by non-linear regression fitting to a double exponential model function. We confirmed that the parameters were highly correlated so that it was difficult to extract a unique set of parameters in the presence of experimental noise. Nevertheless, a reasonable range of decay time constants could be estimated from the grating spacing dependence.

• The Korea Journal of Herbology
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• v.21 no.4
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• pp.159-170
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• 2006

Objectives : Anti-oxidation activities of Malvae Semen and Abutili Semen were compared and evaluated. Methods : We tested the anti-oxidant effect through in vitro experiment and in vivo experiment that induced oxidative stress using ethanol. Results : 1. In the anti-oxidative activities of Malvae Semen and Abutili Semen they had high effects in case of the scavenging activitie of DPPH and superoxide anion radical, and inhibitory effect of linoleic acid oxidation. 2. Malvae Semen had large quantities of phenolic compound than Abutili Semen, but the anti-oxidative activity of Malvae Semen was weaker than that of Abutili Semen. 3. The anti-oxidative effect of Abutili Semen was more strong than that of Malvae Semen in the rat stressed by ethanol. Conclusion : Anti-oxidation activities of Abutili Semen were stronger than those of Malvae Semen. Therefore, the complementary usage of Malvae Semen and Abutili Semen can be considered.

• Korean Journal of Medicinal Crop Science
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• v.18 no.6
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• pp.398-404
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• 2010

Complementary and alternative medicines are considered as a promising research field to develop new therapies for various allergic diseases. In this study, we investigated the anti-allergic effect of Agrimonia pilosa Ledeb (AP) by using passive cutaneous anaphylaxis in mice and its mechanism of action in mast cells. The extract of AP reversibly inhibited degranulation in RBL-2H3 cells and bone marrow-derived mast cells (BMMCs). AP also suppressed the passive cutaneous anaphylaxis inducing by IgE and antigen (Ag) in a dose-dependent manner. In the study to find its mechanism of action, AP inhibited the phosphorylation of Syk kinase, a pivotal protein which is regulated by Src-family kinase for activation of mast cells. In addition, AP also suppressed activation of Akt and Erk1/2 that are critical for the production of cytokines in mast cells. The results strongly suggest that AP exerts anti-allergic activity in vitro and in vivo through the inhibition of activation of Syk in mast cells.