• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.465-466
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• 2017

신재생 에너지를 포함한 마이크로그리드가 활성화 되면서 한 장소에 DC 전력과 AC 전력이 혼재하여 서로 연관이 되는 경우가 빈번히 발생하고 있다. 이 경우 PMS(Power management system) 측에서 AC 전력뿐만 아니라 DC 전력에 대한 정보요구가 증대되고 있다. 따라서 본 연구에서는 AC 전력 및 DC 전력을 동시에 계측할 수 있는 마이크로 그리드용 원격 전력계측기를 개발하여 그 성능을 검증하였다. 또한 전력계 사용 시 결선방식과 전류 상을 자동으로 인식하는 방식을 제안하여 일반인도 쉽게 전력계측을 할 수 있는 알고리즘을 제안하였다.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1659-1660
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• 2006

After end of the 20th environmental problem was became issue. So about mercury free lighting sources are being studied very much. In this paper, a mercury and electrode free bulb was designed. in this bulb was injected mixed of Xe, Ne and Kr Gases. and then the bulb was discharged by 13.56MHz RF Power after spectrum, color coordinates and brightness were measured by spectrum meter CS-1000. Measured results were compared and analyzed, also analysis was able to do a characteristic of a gas defensive fight in proportion to a mixing ratio. Therefore the most of high brightness which was 4500cd/m2 was gained in 1:1 ratio of Xe:Ne at 60W input power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.499-502
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• 2004

In order to detect of insulation problems an early, transformer has to be performed the several tests. The ac current and tan6 of transformer winding insulation were investigated by Schering bridge. Partial discharge(PD) tests are used to evaluate the insulation condition of transformer. The moisture content measurement was conducted using RVM(recovery voltage meter). The RVM test can show that the problem is affecting the paper insulation of transformer. The value of moisture content was 2.3% in main transformer. The insulations of four transformers were judged to be in good condition.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2018-2023
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• 2003

An experiment is conducted for measuring the performance of an air tool, which is operated at 100,000 RPM at the unloaded state with the low torque. An experimental apparatus is developed as the power absorption type dynamometer. Inlet static pressure, flow rate, RPM and force are measured simultaneously. Torque, output power and specific output power are obtained. Those experimental results are compared with the experimental results obtained on a commercial dynamometer. However, no commercial dynamometers are available for measuring the torque above 30,000RPM. In order to use the commercial dynamometer, a reduction gear is applied to the shaft of dynamometer. Torque and power obtained on the commercial dynamometer show 50% lower than those obtained on a power absorption type dynamometer, because the inertia force is added to the air tool rotor for the braking system. Moreover, the starting RPM on the commercial dynamometer is less than 40,000RPM. From the compared results, they show that the power absorption type dynamometer should be applied for measuring the performance of an air tool operating at low torque and high RPM.

• The Journal of Korean Physical Therapy
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• v.23 no.3
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• pp.37-42
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• 2011

Purpose: The principal objective of this study was to evaluate the power output of ultrasound in Korean clinics and compare the value with Korean and global standards. Methods: A total of 69 units were measured for ultrasound power output. The normal range of power output level was ${\pm}30%$ of the output set according to KFDA standards. Device model, manufacturer, ERA, and BNR were obtained via simple questionnaires. A portable ultrasound power meter was used for output measurement. Results: 37 machines, with reported ERA values, were assessed for power output per unit area. Of these machines, 13 (37.14%) were considered to be compliant with US FDA standards at 0.5, 1.0, 1.5, $20W/cm^2$ and 18 (51.43%) were considered within KFDA standards. The remainder of the machines were outside the standard error and evidenced irregular output levels, even though most of them were the same model. Conclusion: Appropriate ultrasound intensity is incredibly important for safety and effective use. Therefore, the KFDA standards regarding ultrasound may require revision in light of global standards, including BNR and ERA additionally, attention should be paid to regular calibration for safe use in clinical practice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.951-962
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• 1992

The layout of electrical power distribution networks never involved communications aspects. As a result their transmission properties severly complicate the use as data links. Futhermore bandwidth as well as transmission power is restricted. Nevertheless, power distribution net works represent a most attractive medium for digital communication purposes due to an ever increasing demand, e.g., for environment management of buildings, office automation, and remote meter reading or security monitoring. In this paper, a power line modem which is capable of transmitting and receiving data at 1200 bps using OOK-BASK through 220V AC power lines is implemented. The receiver includes noncoherent detector and performs soft decision. The OLM circuits can be simplified by use of microprocessor. The PLM also satisfies CENELEC, European standards, and can be applied to home automation system.

• Journal of the Korea Society of Computer and Information
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• v.14 no.8
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• pp.89-96
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• 2009

In the future energy environment, a power information system will meet the real-time capability to process the emergency events, unexpected blackouts or over-load, and the high performance to provide the consumer service events such as remote meter reading. In addition to, it must have facility which is able to process a large information occurred on system effectively. In this paper, we developed a distributed power information system based on event with metadata processing technique which was both load balancing and decreased hot spot using XML that was efficient for information exchange. In order to experiment, we made a reduced future power system with controling power device using wireless communications and we could do experiments through it.

• Journal of Information Processing Systems
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• v.5 no.4
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• pp.221-228
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• 2009

Due to low cost, low-power, and scalability, ZigBee is considered an efficient wireless AMR infrastructure. However, these characteristics of ZigBee can make the devices more vulnerable to unexpected error environments. In this paper, a fault-tolerant wireless AMR network (FWAMR) is proposed, which is designed to improve the robustness of the conventional ZigBee-based AMR systems by coping well with dynamic error environments. The experimental results demonstrate that the FWAMR is considerably fault-tolerant compared with the conventional ZigBee-based AMR network.

• Journal of the Korean Society for Railway
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• v.2 no.1
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• pp.56-66
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• 1999

This purpose of this paper is to perform the readhesion control algorithm of the urban railway traction. A study on readhesion control algorithm is done for the adhesion system. This system has all characteristics of the voltage source converter by a process ability to regenerate power. The traction motor is controlled by IGBT inverter. The test equipment composes traction motor, torque-meter, clutch, and a tubular type of interia mass.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.448-452
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• 2002

We report the number of calibration and test for acoustic field which were conducted in KRISS between the year of 1990 and 2001. The items contain sound level meter and calibrator for calibration and sound absorption coefficient, transmission loss, sound pressure level of siren, sound pressure level and power of acoustic instrument and relative accessories for test. The data show that the number of them have been increased continuously.