• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.72.1-72
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• 2003

Generally, plants defend themselves against pathogens by structural and biochemical reactions. Defense structures act as physical barriers and inhibit the pathogen from gaining entrance and spreading through the plant. Xanthomonas axonopodis pv glycines, the causal pathogen of bacterial pustule of soybean, causes hypersensitive response (HR). When pepper fruits were inoculated with X. axonopodis pv. glycines, in situ, time-series defense-related structural changes occurred in the inoculated sites. Early responses were programmed cell death (PCD), characterized by condensation and vacuolization of the cytoplasm, condensation of nuclear materials, and fragmentation of the nuclear DNA, which were observed by transmission electron microscopy. Nuclear fragmentation was proven by TUNEL method under confocal laser scanning microscopy and DNA laddering through eletrophoresis. At later stages, plant responses were cell elongation and cell division, forming a periderm-like boundary layer that demarcated healthy tissues from the inoculation sites. Using several stains such as toluidine blue, sudan IV, annexin V, and phloroglucinol-HCl, defense-related materials and structural changes were also examined.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.380-385
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• 2020

Over the past decade, small robots have been of particular interest in the engineering field. Among the various types of small robots, biomimetic robots, which mimic animals and insects, have been developed for special activities in areas where humans cannot physically access. The optimal motion of a walking robot can be determined by the characteristics of the traversed surface (e.g., roughness, curvature, slope, materials, etc.). This study proposes three types of piezoelectric structures using different driving mechanisms, depending on the application range of the small walking robots. Dynamic modeling using computer-aided engineering optimized the shape of the robot to maximize its moving characteristics, and the results were also verified through its fabrication and experimentation. Three types of robots, named by their actuator shapes as I, π, & T-shape, were proposed regarding application for small scale ambulatory robots to different terrain conditions. Among these, the T-shaped robots were shown to have a wide range of speeds (from 2 mm/s up to 255 mm/s) and good carrying capacity (up to 10 g at 50 mm/s) through driving experiments. Based on this study, we proposed possible application areas for the three types of walking robot actuators.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.2
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• pp.147-158
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• 2020

Korea Ministry of National Defense has directed the state-of-the-art technology Forces troops structures that can respond to security threats in all directions through the Defense Innovation 2.0, which aims to reorganize the personnel and organizations in response to population decline. An implement of effective analysis to maintain combat power is necessary due to possible restrictions on combat power, especially in division of mobilization where reserve manpower is operated frequently. In this study, the normal operations of the reserve officers were investigated, the direct effects of the combat forces of the reserve officers was analyzed using ARENA modeling, and the budget required to operate the innovation and indirect effects of employment of veterans were studied. The result of the simulation proved to be effective in demonstrating unit combat power when the reserve officer was in full-time operations and economic benefits were also significant in terms of efficiency of defense budget management.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.449-457
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• 2016

Cylindrical array sensor of a surface ship to detect an enemy is normally installed in the sonar dome. Reflected signals by some structures inside the sonar dome make unwanted signals. To minimize unwanted signals, acoustic baffles are used. Acoustic baffles are hard to install and replace, so the durability of acoustic baffles is an important design parameter. To verify the durability of acoustic baffle, accelerated aging tests according to temperature and pressure were performed. Acoustic baffle specimens were made and they are tested the visual and the performance (echo reduction and transmission loss) inspection before and after aging. After the inspection, the effect of accelerated aging of the acoustic baffles were discussed.

• Journal of electromagnetic engineering and science
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• v.9 no.1
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• pp.1-6
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• 2009

An effective method is proposed to suppress the second-order beams(SOBs) that result from the cross-polarized fields of 2D edge slot arrays. By rearranging the conventional sequence of stacking waveguides, the SOBs are shown to be considerably reduced and the 9 dB suppression is obtained. The optimal sequence is obtained from the genetic and exhaustive searches and its effects are verified using near-field measurements as well as theoretical estimation. Since the proposed method requires no additional polarizing structures such as baffles, it is very easy and cost-effective to implement.

• International Journal of Control, Automation, and Systems
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• v.4 no.5
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• pp.559-566
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• 2006

In the real system application, the interacting multiple model (IMM) based algorithm requires less computing resources as well as a good performance with respect to the various target maneuverings. And it further requires an easy design procedure in terms of its structures and parameters. To solve these problems, a fuzzy interacting multiple model (FIMM) algorithm, which is based on the basis sub-models defined by considering the maneuvering property and the time-varying mode transition probabilities designed by using the mode probabilities as inputs of a fuzzy decision maker, is proposed. To verify the performance of the proposed algorithm, airborne target tracking is performed. Simulation results show that the FIMM algorithm solves all problems in the real system application of the IMM based algorithm.

• Steel and Composite Structures
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• v.17 no.2
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• pp.185-198
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• 2014

Carbon-manganese steel A42 (French standards) is used in steam generator pipes of nuclear center and subject to low cycle fatigue (LCF) loads. In order to obtain the material LCF behavior, the tests are implemented in a hydraulic fatigue machine. The LCF plastic deformation and cyclic stress in macroscope have been influenced by the accumulated low cycle fatigue damage. The constitutive kinematic and isotropic hardening modeling is modified with coupling fatigue damage to describe the fatigue behavior. The improved model seems to be good agreement with the test results.

• Structural Engineering and Mechanics
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• v.13 no.2
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• pp.135-154
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• 2002

This paper presents the convected material frame approach to study the nonlinear behavior of inelastic frame structures. The convected material frame approach is a modification of the co-rotational approximation by incorporating an adaptive convected material frame in the basic definition of the displacement vector and strain tensor. In the formulation, each discrete element is associated with a local coordinate system that rotates and translates with the element. For each load increment, the corresponding strain-displacement and nodal force-stress relationships are defined in the updated local coordinates, and based on the updated element geometry. The rigid body motion and deformation displacements are decoupled for each increment. This modified approach incorporates the geometrical nonlinearities through the continuous updating of the material frame geometry. A generalized nonlinear function is used to derive the inelastic constitutive relation and the kinematic hardening is considered. The equation of motion is integrated by an explicit procedure and it involves only vector assemblage and vector storage in the analysis by assuming a lumped mass matrix of diagonal form. Several numerical examples are demonstrated in close agreement with the solutions obtained by the ANSYS code. Numerical studies show that the proposed approach is capable of investigating large deflection of inelastic planar structures and providing an excellent numerical performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.7
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• pp.467-472
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• 2015

Thermal batteries are primary power sources for military applications requiring high reliability, robustness and long storage life. Conventional electrodes for thermal batteries are prepared by compacting powder mixtures into pellets. Separator is composed of halide mixture, such as LiCl-KCl eutectic salt, blended with MgO to immobilize the molten salt. In order to increase the power density and energy density, the resistance of electrolyte should be reduced because the resistance of electrolyte is predominant in thermal batteries. In this study, wetting behaviors and impregnation weight of molten salts as well as the micro structures of ceramic felt were investigated to be applicable to thin electrolyte. Discharge performances of single cell with the ceramic separator impregnated by molten salt were evaluated also. Zirconia felt with high porosity and large pore outperformed alumina felt in wetting characteristics and molten salt impregnation as well as discharge performances. Based on the results of this study, ceramic felt separator impregnated with molten salt have revealed as an alternative of conventional thick MgO based separator with no conspicuous sign of thermal runaway by short circuit.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.444-449
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• 2020

I proposed small ambulatory robot actuators using piezoelectric benders. In order to make the motion of the biomimetic robot legs similar to the movements of the cockroaches or similar insects, two pairs of legs in the diagonal direction in the four leg structures are required to make the same movement. And elliptical displacement is realized by taking into account horizontal and vertical displacement of multimode oscillations and driving them by electrical signals with differences step by step, for example of 90° the T-shaped robot actuator showed wide range of speed (From 2 mm/sec. up to 266 mm/sec.) and ability of transportation (up to 10 g with 50 mm/s). Locomotive performance of the robot was competitive to the preceding robots, and moreover, the modular type actuators of a segmented myriapods robot could be added and removed for different tasks or performances.