• Korean Journal of Pharmacognosy
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• v.51 no.2
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• pp.115-121
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• 2020

Caenorhabditis elegans model system was used to investigate the antioxidant activity of methanol extract of Mallotus japonicus twigs. The ethyl acetate soluble fraction of the M. japonicus methanol extract showed the best DPPH radical scavenging activity. The ethyl acetate fraction was measured for the activity of superoxide dismutase (SOD), catalase, and oxidative stress tolerance by using C. elegans along with reactive oxygen species (ROS) level. In addition, to confirm that the regulation of the stress response gene is responsible for the increased stress tolerance of C. elegans treated by the ethyl acetate fraction, SOD-3 expression was measured using a transgenic strain. As a result, the ethyl acetate fraction increased SOD and catalase activity, and decreased ROS accumulation in a dose-dependent manner. In addition, the ethyl acetate fraction-treated CF1553 worm showed higher SOD-3::GFP intensity than the control worm.

• Journal of Mechanical Science and Technology
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• v.20 no.2
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• pp.234-241
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• 2006

A functional external fixator system for bone deformity near the joints using worm gear was developed for curing the angle difference in fracture bones while the lengthening bar was developed for curing the differences in length, also in fracture bones. Both experiments and FE analysis were performed to compare the elastic stiffness in several loading modes and to improve the functional external fixator system for bone deformity near joints. The FE model using compressive and bending FE analysis was applied due to the angle differentiations. The results indicate that compressive stiffness value in the experiment was 175.43N/mm, bending stiffness value in the experiment was 259.74 N/mm, compressive stiffness value in the FEA was 188.67 N/mm, and bending stiffness value in the FEA was 285.71 N/mm. Errors between experiments and FEA were less than $10\%$ in both the 'compressive stiffness and the bending stiffness. The maximum stress (157 MPa) applied to the angle of the clamp was lower than the yield stress (176.4 MPa) of SUS316L. The degree of stiffness in both axial compression and bending of the new fixator are about 2 times greater than other products, with the exception of EBI (2003).

• Korean Journal of Pharmacognosy
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• v.52 no.4
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• pp.251-256
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• 2021

Oat, the seeds of Avena sativa L. (Gramineae), is an important dietary staple for people in many countries. Previous studies reported that A. sativa had various pharmacological effects such as anti-inflammatory, antitumor, neurotonic, and antispasmodic activities. In this study, Caenorhabditis elegans model system was used to investigate the antioxidant activity of methanol extract of oat. The ethyl acetate soluble fraction of the oat methanol extract showed the best DPPH radical scavenging activity. The ethyl acetate fraction was measured for the activity of superoxide dismutase (SOD), catalase, and oxidative stress tolerance by using C. elegans along with reactive oxygen species (ROS) level. In addition, to confirm that the regulation of the stress response gene is responsible for the increased stress tolerance of C. elegans treated by the ethyl acetate fraction, SOD-3 expression was measured using GFP-expressing transgenic worm. As a result, the ethyl acetate fraction increased SOD and catalase activities, and decreased ROS accumulation in a dose-dependent manner. In addition, the ethyl acetate fraction-treated CF1553 worm showed higher SOD-3::GFP intensity compared to the control.

• Korean Journal of Pharmacognosy
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• v.53 no.4
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• pp.207-212
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• 2022

Through the Caenorhabditis elegans model system, the antioxidant activity of methanol extract of Ixeis dentata was investigated. The ethyl acetate soluble fraction of the I. dentata methanol extract showed the best DPPH radical scavenging activity. The ethyl acetate fraction was measured for the activity of superoxide dismutase (SOD), catalase, and oxidative stress tolerance by using C. elegans along with reactive oxygen species (ROS) level. In addition, to confirm that the regulation of the stress response gene is responsible for the increased stress tolerance of C. elegans treated by the ethyl acetate fraction, SOD-3 expression was measured using a transgenic strain (CF1553). As a result, the ethyl acetate fraction increased SOD and catalase activity, and decreased ROS accumulation in a dose-dependent manner. In addition, the ethyl acetate fraction-treated CF1553 worm showed higher SOD-3::GFP intensity than the control worm.

• Korean Journal of Pharmacognosy
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• v.53 no.2
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• pp.96-101
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• 2022

Caenorhabditis elegans model system was used to investigate the antioxidant activity of methanol extract of Melampyrum roseum (Scrophulariaceae). The ethyl acetate soluble fraction of the M. roseum methanol extract showed the best DPPH radical scavenging activity. The ethyl acetate fraction was measured for the activity of superoxide dismutase (SOD), catalase, and oxidative stress tolerance by using C. elegans along with reactive oxygen species (ROS) level. In addition, to confirm that the regulation of the stress response gene is responsible for the increased stress tolerance of C. elegans treated by the ethyl acetate fraction, SOD-3 expression was measured using a transgenic strain. As a result, the ethyl acetate fraction increased SOD and catalase activity, and decreased ROS accumulation in a dose-dependent manner. In addition, the ethyl acetate fraction-treated CF1553 worm showed higher SOD-3::GFP intensity than the control worm.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10a
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• pp.114-115
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• 2007

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.125-130
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• 2012

The nematode Caenorhabditis elegans is a widely used model organism in biological research. Thanks to the availability of well-established knowledge about its neural connectivity, a wide range of studies have been attempted to uncover the relationship between behaviors and the responsible neurons. In our research, the adaptive behavior of C. elegans in solid environments with different surface rigidities is investigated, where the worm adapts to different mechanical stiffnesses by modulating its crawling waveform. The amplitude and wavelength of the crawling waveform decrease as the environment becomes more rigid. Interestingly, the mechanosensation-defective mutant shows different responses to the surface rigidity compared to those of the wild-type worm. To explain the adaptation process in mechanically different environments, we suggest a plausible neural circuit model.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.995-1006
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• 2011

A time series can be decomposed into simple components with a multiscale method. Empirical mode decomposition(EMD) is a recently invented multiscale method in Huang et al. (1998). It is natural to apply a classical prediction method such a vector autoregressive(AR) model to the obtained simple components instead of the original time series; in addition, a prediction procedure combining a classical prediction model to EMD and Hilbert spectrum is proposed in Kim et al. (2008). In this paper, we suggest to adopt principal component analysis(PCA) to the prediction procedure that enables the efficient selection of input variables among obtained components by EMD. We discuss the utility of adopting PCA in the prediction procedure based on EMD and Hilbert spectrum and analyze the daily worm account data by the proposed PCA adopted prediction method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2186-2203
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• 2020

Security administrators of companies and organizations need to come up with proper countermeasures against cyber-attacks considering infrastructures and security policies in their possession. In order to develop and verify such countermeasures, the administrators should be able to reenact both cyber-attacks and defenses. Simulations can be useful for the reenactment by overcoming its limitations including high risk and cost. If the administrators are able to design various scenarios of cyber-attacks and to develop simulation models from their viewpoints, they can simulate desired situations and observe the results more easily. It is challenging to simulate cyber-security issues, because there is lack of theoretical basis for modeling a wide range of the security field as well as pre-defined basic components used to model cyber-attacks. In this paper, we propose a modeling method for cyber-security simulations by developing a basic component and a composite model, called Abstracted Cyber-Security Unit Model (ACSUM) and Abstracted Cyber-security SIMulation model (ACSIM), respectively. The proposed models are based on DEVS(Discrete Event systems Specification) formalism, a modeling theory for discrete event simulations. We develop attack scenarios by sequencing attack behaviors using ACSUMs and then model ACSIMs by combining and abstracting the ACSUMs from a security perspective. The concepts of ACSUM and ACSIM enable the security administrators to simulate numerous cyber-security issues from their viewpoints. As a case study, we model a worm scenario using ACSUM and simulate three types of simulation models based on ACSIM from a different security perspective.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.878-884
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• 2005

This paper presents an algorithm for the precision motion control based on the dynamic characteristics of piezoelectric actuators in the inchworm. The dynamic characteristics are identified by the frequency domain modeling technique using the experimental data. For the motion control, the hysteresis behavior is compensated by the inverse hysteresis model. The dynamic stiffness of an inchworm is generally low compared to its driving condition, so mechanical vibration may degenerate the motion accuracy of the inchworm. The Sliding mode controller and the Kalman filter are designed for motion control of the inch-worm.