• Proceedings of the KWS Conference
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• 2002.10a
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• pp.816-825
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• 2002

During the manufacture of a ship, longitudinal deformation is produced by fillet welding on the BuiltUp beam used to improve the longitudinal strength of a ship. This deformation needs a correcting process separate from a manufacture process and decreases productivity and quality. This deformation is caused by welding moment, which is the value multiplied the shrinking force due to welding by the distance from the neutral axis on a cross section of Built-Up beam. This deformation can be offset by generating a moment which is the same magnitude with and is located in an opposite direction to the welding moment on web plate by induction heating. Accordingly, this study clarifies the creation mechanism of the longitudinal deformation on Built-Up beam with FEM analysis and presents the preventative method of this deformation by induction heating basing the mechanism and verifies its validity through analysis and experiments. The induction heating used here is performed by deciding its location and quantity with experiments and simple equations and by applying them to areal structure.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.516-518
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• 2005

This paper presents a distance protection algorithm a lied to the linked line for interconnecting wind farm with the utility. The capacity of wind farm is lower than utility system and its fault current level is very low. When a high resistance fault occurs in the linked line, it is difficult to detect accurate fault distance because of reactance effect. By using the characteristic of equivalent source impedance of induction generator which is compensated by capacitor bank and characteristic of the capacity of wind farm, this paper proposes improved distance protection algorithm applied to the linked line. A series of PSCAD/EMTDC simulation results have shown effectiveness of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1086-1091
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• 2005

This paper focuses on intelligent control of induction motor by hybrid system consisting of GA-PSO. Induction motor has been using in industrial area. However, it is challengeable on how we control effectively. From this point, an optimal solution using GA (Genetic Algorithm) and PSO (Particle Swarm Optimization) is introduced to intelligent control. In this case, it is possible to obtain local solution because chromosomes or individuals which have only a close affinity can convergent. To improve an optimal learning solution of control, This paper deal with applying PSO and Euclidian data distance to mutation procedure on GA's differentiation. Through this approaches, we can have global and local optimal solution together, and the faster and the exact optimal solution without any local solution. Four test functions are used for proof of this suggested algorithm.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.243-245
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• 2005

This paper presents a wired and wireless linked remote control system. Ethernet based network communication is used for long distance management and 2.4GHz RF network is adopted for the local area communication between the main network and the ballast. For the effective remote control and management including dimming using wired and wireless linked digital communication networks, control circuit of the ballast is implemented with fully digital circuit using MCU and EPLD. In this paper, the proper frame structure is proposed for the digital-remote lighting-control system and the detailed system configurations including fully digital controlled ballast for the induction lamp are described.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.215-218
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• 2007

In this paper, we have analyzed the effects from the change of separation distance between grounding equipment at end of telecommunication line and the inducting facilities in power inducting situation. In the result of measurement, we can see that as the separation distance between grounding equipment ant end of telecommunication line and the inducting facility become longer, the induced noise level and PIF level is decreased. From the another experiment results about the effect of changing the impedance size in both ends of telecommunication line, however, we already knew that as the ground impedance at either end of the telecommunication line become grower, the noise level is increased, and as the ground impedance at either end of the telecommunication line become smaller, the noise level is decreased. Hence we can not define the relationship exactly between separation distance from inducting facility to inducted facility and the induced noise level because when the grounding equipment is moved, its impedance size is changed too. In conclusion, changing the separation distance between grounding equipment at end of telecommunication line and the inducting facilities have not influence on the induced noise level.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.37-46
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• 1995

Along with the recent trend of complexity and long distance transmission in power system, dynamic analysis of stability considering the load characteristics is an important subject. In this paper, the influence of the induction motor loads on the power system voltage is investigated. The influence of the inductive load ratio and the inertia of induction motor on the voltage response of the power system are examined, and in the case of the high percentage of the induction motor load, induction motors in the power system can lead to transient voltage instability even under the system condition such as switching operation. The application of static condenser(SC) to prevent the transient voltage instability is introduced.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.104-111
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• 2004

In this paper, we propose a diagnosis algorithm to detect faults of induction motor using LDA First, after reducing the input dimension of a current value measured by experiment at each period using PCA method, we extract characteristic vectors for each fault using LDA Next, we analyze the driving condition of an induction motor using the Euclidean distance between a precalculated characteristic vector and an input vector. Finally, from the experiments under various noise conditions showing the properties of the LDA method, we obtained better results than the case of using the PCA method.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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• pp.334-344
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• 2022

In this study, we used underwater acoustics to analyze the spatial and temporal distribution characteristics of largehead hairtail (Trichiurus leptueus) based on the luminous thronging of metal halide fishing lamps and induction fishing lamps. As a result, the illuminating power was approximately 1.3 times higher using the metal halide fishing lamp whereas the density of hairtals by distance was approximately 1.9 times higher using the induction fishing lamp. Regarding water depth distribution, hairtails were detected depths of 25-30 m during August and at all water depths in November as assessed using fishing lamps.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.772-778
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• 2005

In this paper, we designed the cylindrical type light source that had a electromagnetic principle of inductively coupled plasma, and measured its electrical-optical properties. Using the principle of transformer, electrically equivalent circuit of cylindrical type light source was analyzed. According to the parameters of electromagnetic induction which were diameter of coil with $0.3\~1.2\;mm{\Phi}$, number of turns with $4\~12$ turns, distance with $40\~120$ mm and RF power with $10\~150$ W, the electrical and optical properties were measured. When diameter of coil was $0.3\;mm{\Phi}$, number of turns was 8 turns and distance was 40 mm, the highest brightness of 29,730 $cd/m^2$ was shown with RF power 150 W. The relationship between electromagnetic induction and plasma discharges was shown by mode transition from E-mode to H-mode.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.353-356
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• 2015

Due to high oil prices, environmental pollution, the study of electric vehicles have been actively promoted. Charger for the electric vehicle is being developed using wireless rather than cable options. In this paper, we got more efficiency from using a superconducting transmission coil compared to using a normal coil. We implemented a wireless power transmission system using a magnetic induction at a frequency of 63.1 kHz. For comparison, a transmitter was designed using a superconducting coil and a normal coil. In addition, a receiver used a normal coil to apply for electric vehicles. The applied voltage and current were12 V and 5 A. Efficiency at a distance of 40 ~ 80 mm was measured. As a result, the superconducting transmission coil had a higher efficiency than the normal transmission coil. However, the receiving coil should be normal conductor for stable operation considering that it was put in moving electric vehicle. The efficiency was increased to 44 % at a distance of 40 mm when the diameter of normal receiving coil was 120 mm.