• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.406-408
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• 1996

This paper describes the BLDC motor which is applicated for a top front loading domestic washing machine. This motor is adopted direct drive washing machine without gear-belt-pulley system. Because gear box is removed, machine volume and noise are reduced. Moreover mechanical troubles in gear box are removed. Realization of variable speed region through of PWM control and high speed is able to efficient washing and spinning.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.2
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• pp.1-8
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• 2010

In order to determine the possibility of using NDGPS signals for flight operations, in-flight measurements of signals transmitted from various ground reference stations(RS) were conducted along the air routes of South Korea. Signal strength and signal to noise ratio(SNR) data were collected along domestic flight routes and recorded with time. By using three-dimensional geographical position data of the aircraft, signal strength data of en-route position were calculated and used to obtain scatter-plot of signal strength. These results were used to outline the effective coverage and field strength hemispheres of the selected DGPS signals.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.40-43
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• 2003

An electric propulsion system integrated with the ship service distribution system offers the naval architect considerable flexibility, and often the choice of a more affordable ship to acquire and operate as compared to a segregated mechanical drive option. United States of America navy announced in 2000 that they selected the electric propulsion system on next generation warship. Specially there is excellent advantages in superconductivity motors which can have higher efficiency, less vibration and noise, smaller dimensions compared with the conventional motors. The 5 MW HTS motor for warship test of electric propulsion was developed and tested. Also it was contracted between AMSC and United States of America navy to develop a 36.5 MW HTS motor in 3 years since March 3, 2003. This paper deals with the technical development tendency of HTS motors in foreign countries as well as in domestic, and it is focused on the application of HIS motors to the electrical propulsion system.

• Journal of the Korean Society for Railway
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• v.2 no.3
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• pp.54-60
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• 1999

In this paper, design and construction process for the standardized electric motor car according to standard specification is described. Aluminum extrusion profiles and power and control system made domestically are used in the electric motor car. Also, plug-sliding door system for noise reduction and automatic train control system are developed and applied. Through the development of the electric motor car, most electric and control systems can be substituted by domestic standard systems, and safety and reliability of electric motor cars can be secured.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.10
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• pp.10-20
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• 1994

This paper presents a CATV SMS (Status Monitoring System) using HDLC (High Level Data Link Contorl) protocol and the system implementation.The system specifications were derived from the analysis of technical status and requirement of the domestic CATV industry. For the interoperability with a global network management system in the future, HDLC protocol was adopted in the system. The system performance was improved by using the communication controller chip and the large data buffer. For reducting the communication problems induced by accumulated noise in up-stream data channels, the system was designed that the different communication channel can be assigned to each proper mass of terminal. The operating software was designed with menu driven user interface and have various functions for the convenience of users. The test result of the implemented system at the experimental network showed good performance and suitability for a coaxial CATV Status Monitoring System.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.699-702
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• 2005

This study evaluates the properties of porous concrete for pavement according to content of silica fume and steel fiber. The results of the test indicate that in every condition, the void ratio and the coefficient of water permeability of porous concrete for pavement satisfy both the domestic standards and proposition values. Among the properties of strength, the compressive strength satisfies the standards in the specification of KNHC as for every factor of mixture but in the case of the flexural strength, more than $0.6vol.\%$ of steel fiber satisfied the JCI proposition values. The case when silica fume and steel fiber are used simultaneously presents the strongest durability and Noise Reduction Coefficient is 0.48 to prove that it possesses almost $50\%$ sound absorption.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.144-149
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• 2000

Porous cement concrete was developed to prevent hydroplaning of airway pavement or to reduce noise emission in highway. In has been introduced in domestic since early 1980' and applied to a pedestrian road or bike way. The concrete, however, has problems such as lack of optimized mix design, low strength and deterioration, etc. The purpose of this study is to manufacture porous cement concrete using blast-furnace slag to enhance mechanical properties. The results of this study are as follows; the compressive strength range is 102∼247kgf/㎠, the tensile strength range is 16∼70kgf/㎠, the bending strength range is 43∼70kgf/㎠, and the coefficient permeability range is 6.79 ×10-2∼1.17∼10-1cm/sec. To develope high-performance porous concrete, further studies are needed on optimum mixture of fineness modulus and admixture.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.5
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• pp.58-67
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• 1994

In this paper, It was designed the 2.8GHz local oscillator which convert 14.5 14.8GHz uplink frequency to 11.7 12.0GHz downlink frequency by the receiving mixer on the communication satellite transponder according to the rating of domestic satellite. Mukunghwa 1. To prevent the variation of the communication channel bandwidth, it needs a high stability and low phase noise characteristics. So we designed to get the target frequencey by multipling the output signal from the crystal oscillator. We got the simplicity of the circuit by manufacturing the X4 multiplier with transistor which is ordinarily used as a device of a below X3 multiplier for the efficiency.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.468-475
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• 2000

An air spring was accepted for rail vehicle secondary suspension to reduce and absorb tile vibration and the noise. The air spring for the electric railway was developed with domestic technology, which consisted of a cord reinforced rubber bellows, a upper plate, a lower plate and a stopper rubber spring The fatigue test was conducted in laboratory by using servo hydraulic fatigue testing system to verify the durability. And to guarantee the adaptation of this air spring, the ride comfort and the air pressure variation were measured in train test on Boondang line.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1262-1270
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• 2010

The next generation domestic high speed railway system is a power dispersed type and uses vector control method for motor speed control. Nowadays, inverter driven induction motor system is widely used. However, recently PMSM drives are deeply considered as a alternative candidate instead of an induction motor driven system due to their advantages in efficiency, noise reduction and maintenance. In this paper, the maximum torque control approach is presented for the IPMSM drives with reluctance torque. The applied control method uses maximum torque control per ampere technique. Simulation programs based on Matlab/Simulink are developed. Finally the designed system is verified by simulation and their characteristics are analyzed by the simulation results.