• Journal of the Microelectronics and Packaging Society
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• v.13 no.3 s.40
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• pp.27-32
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• 2006

The occurrence frequency of lightning and surge from the weather accident is increasing recently, which the damage scale have been enlarged every year. A protection system development to solve these problems have been risen to a multinational concern field. In this paper, a novel protection system is proposed to restrain lightning and various surges which happen in electricity and communication equipment. The proposed protection system is designed to the structure to restrain the rise of the earth potential which is become to the problem of conventional protection system. The secondary damage as a result does not happen. The practicality of the developed surge protection system is proved through various accident occurrence simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1078-1085
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• 2006

In earthing technologies, the intrusion of the surge wave can be protected when the earthing resistance is as low as several ohms. However, the cost fer realizing such a low resistance is quite high. Therefore it is important to determine appropriate target value of the earthing resistance to install cost-effective grounding system. In this work, we have proposed an optimization method of the earthing resistance according to the various environmental parameters by using a numerical simulator We have also developed new catalyst composed of water-soluble alkaline elements and activated carbon and investigated its electrical characteristics for enhancement of the earthing qualities.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.5
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• pp.257-262
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• 2006

To evaluate the change in protective levels of zinc oxide (ZnO) varistors after the surge absorption, this paper investigated the effects of the number of injection and amplitude of lightning surges on the life of ZnO varistors for low voltages. Leakage currents flowing through ZnO varistors subjected to the $8/20{\mu}s$ impulse currents under 60 Hz AC voltages were measured. The surge simulator system ECAT that can generate $8/20{\mu}s$ impulse currents with a peak short-circuit of 5 $[kA_p]$ was used. The ZnO varistor leakage current increases with exposure to impulse current, and the number of injection of $8/20{\mu}s$ impulse currents to breakdown was inversely proportional to the amplitude of the test current. Behaviors of ZnO varistor leakage currents were strongly dependent on the number of injection and amplitude of $8/20{\mu}s$ impulse currents. ZnO varistors degrade gradually when subjected to impulse current, and the resistive leakage current flowing through ZnO varistors subjected to the $8/20{\mu}s$ impulse currents under 60 Hz AC voltages was significantly increased after a certain number of injection that is dependent on the amplitude of the test impulse current. As a result, the life of ZnO varistors mainly depends on the amplitude and occurrence frequency of lightning surges.

• The Journal of the Convergence on Culture Technology
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• v.1 no.1
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• pp.73-77
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• 2015

Existing sports simulators on the market focus on the motion of platform or reality expression using basic visual contents, and are limited to entertainment products. Therefore, the stimulus on 5 senses is not good enough to be applied on high virtual reality. Moreover, there are not enough professional contents to be applied to an educational sports simulator. In this paper, we developed a sport platform by separating the multi axis based common platform module and the sports application module. We designed the common platform which has 4 degrees of freedom such as surge, sway, heave and yaw motion. This platform has the purpose of stabilizing motion and minimizing interference. The changeable sport module which is attached to the common module has 2 degrees of freedom such as roll and pitch, so that it can be applied to the various fields of 2 degrees of freedom virtual reality sports such as horse riding and yacht.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.8
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• pp.33-44
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• 2000

The lightning with high voltage and current can enter the basestations for mobile communication through their antenna. The device which can protect the basestation against the lightning, is surge arrestor. In this paper, the concept, kind, operating mechanism, design and fabrication of surge arrestor were studied. Based on the studied data, variable surge arrestors were designed for the current mobile communication service like a cellular, GSM and PCS and the next generation mobile communication like a IMT-2000. Computer simulation for the prediction of their characteristics and inner structure optimization for the improvement of their electrical characteristics were carried with high frequency 3D structure simulator. Quarter wave short stub surge arrestors for IMT-2000 were fabricated with their final design and then the measurement of electrical characteristics and the lightning test were executed. As a results of measurement, we obtained below 1.05 of VSWR, -0.035 dB of insertion loss, -150 dBc of intermodulation and 7∼ll V of residual voltage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.60-67
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• 2006

This paper presents the protection effect of surge protective devices(SPDs) according to the conditions of installations. To propose the effective protection measures of information and communication equipments against lightning surges, actual-sized experiments in relation to the protection effects on the positions of installations of SPDs, the length of branch circuit, the wiring methods, and the materials of conduit, were conducted. The effective method of protecting information and communication equipments from lightning surges is to install SPDs in the vicinity of input terminals of each electronic equipments to be protected. The wiring method of connecting an SPD minimizing the length of leads is desirable when point-to-point wiring is to be used.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.338-341
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• 2006

This paper presents the leakage current characteristics of ZnO varistors exposed to the $8/20{\mu}s$ lightning impulse currents as functions of the number of injection and amplitude of impulse currents. The surge simulator system ECAT that can generate $8/20{\mu}s$ impulse currents with a peak short-circuit of $5[kA_p]$ was used. Leakage currents flowing through ZnO varistors subjected to the $8/20{\mu}s$ impulse currents were measured under 60 Hz AC voltages. The trend curves of resistive leakage current of ZnO varistors were analytically calculated.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.88-97
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• 1993

Electrostatic Discharge(ESD) is one of the major reliability, issues for today's VLSI production. Since the gate oxide with a thickness of 100~300$\AA$ is vulnerable to several thousand volt of ESD surge, it is necessary to control the ESD events and design an efficient protection circuit. In this paper, physical mechanism of the catastrophic ESD damage is investigated by transient analysis based upon Human Body Model(HBM). Using two-dimensional electrothermal simulator, we study the failure mechanism of the output protection devices by ESD and discuss the design issues for the optimun protection network.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.228-238
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• 2017

The CALEB10 is a multi-legged biomimetic underwater robot. In the last research, we developed a swimming pattern named ESPG (Extended Swimming Pattern Generator) by observing diving beetle's swimming actions and experimented with a positive buoyancy state in which CALEB10 floats on the water. In this paper, however, we have experimented with CALEB10 in a neutral buoyancy state where it is completely immersed in water for pitch motion control experiment. And we found that CALEB10 was unstably swimming in the pitch direction in the neutral buoyancy state and analyzed that the reason was due to the weight proportion of the legs. In this paper, we propose a pitch motion control method to mimic the pitch motion of diving beetles and to solve the problem of CALEB10 unstably swimming in the pitch direction. To control the pitch motion, we use the method of controlling additional joints while swimming with the ESPG. The method of obtaining propulsive force by the motion of the leg has a problem of giving propulsive force in the reverse direction when swimming in the surge direction, but this new control method has an advantage that a propulsive moment generated by a swimming action only on a target pitch value. To demonstrate validity this new control method, we designed a dynamics-based simulator environment. And the control performance to the target pitch value was verified through simulation and underwater experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3623-3627
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• 2012

The modern society has become full-fledged entry into the information age since spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4GHz band which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 5GHz band came to be interested. In this paper, we studied the design and fabrication of u-slot microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, u-slot microstrip patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer.