• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.351-358
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• 2018

In this study, we propose a method of suppressing the leakage noise signal of motor assembly through the test. The motor assembly is mounted on outside of the aircraft to rotate an antenna and must satisfy RE102 requirement on MIL-STD-461F in terms of electromagnetic interference. It is confirmed by RE102 test result hat the leakage noise signal of the equipment occurs due to external influx through the power and control cable and rotation of the motor. And it is ascertained that the part where internal/external physical shielding is difficult to rotate is the leakage path. To reduce the leakage noise signal, the electrical ground reinforcement and the electric shielding structure considering the operation of the equipment is applied and it is verified that the requirement is satisfied. Finally, we verified that required specification are met by applying circular corrugated choke with interlocking shapes and conductive grease to the noise leakage path.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.515-519
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• 1997

The purpose of this study is to reduce the fast neutron fluence at the reactor pressure vessel(RPV) and to provide a basis for plant-life extension. In this study, different neutron absorbers were employed in the core outer assemblies of Kori Unit 1 Cycle 14. The modified assemblies were used to calculate fast neutron fluence at the RPV and to evaluate reduction of outer assembly power and total power in core. By comparison with the case of no suppression fixture, the fast neutron fluence of a case with two rows stainless steel around the assembly with natural uranium pins is decreased by 85.8%. It is noted that the modification of outer assembly is more efficient than the previous low leakage loading pattern (LLLP) applied to Kori Unit 1. Also, compared fast neutron fluence in Cycle 1 with Cycle 14, fast neutron fluence at the RPV between Cycle 1 and Cycle 14 is not significantly different. It is found that LLLP applied to the Kori Unit 1 has not contributed to fast neutron fluence reduction at the RPV.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.2 s.332
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• pp.31-40
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• 2005

The Multi-Threshold CMOS (MTCMOS) technology provides a solution to the high performance and low power design requirements of mobile computing applications. In this paper, we (i) motivate the post-mask-tooling performance enhancement technique combined with the MTCMOS leakage current suppression technology, and (ii) develop a practical MTCMOS ASIC design methodology which fine-tunes and integrates best-in-class techniques and commercially available tools to fix the new design issues related to the MTCMOS technology. Towards validating the proposed techniques, a Personal Digital Assistant (PDA) processor has been implemented using the methodology, and a 0.18um Process. The fabricated PDA processor operates at 333MHz which has been improved about $23\%$ at no additional cost of redesign and masks, and consumes about 2uW of standby mode leakage power which could have been three orders of magnitude larger if the MTCMOS technology was not applied.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.1
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• pp.31-40
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• 2014

This paper describes an optimal configuration for multi-central inverters in a medium-voltage (MV) grid, which is suitable for large-scale photovoltaic (PV) power plants. We theoretically analyze a proposed common-mode equivalent model for problems associated with multi-central transformerless-type three-phase full bridge(3-FB) PV inverters employing two-winding MV transformers. We propose a synchronized PWM control strategy to effectively reduce the common-mode voltages that may simultaneously occur. In addition, we propose that the existing 3-FB topology may also have the configuration of a multi-central inverter with a two-winding MV transformer by making a simple circuit modification. Simulation and experimental results of three 350kW PV inverters in a multi-central configuration verify the effectiveness of the proposed synchronization control strategy. The modified transformerless-type 3-FB topology for a multi-central PV inverter configuration is verified using an experimental prototype of a 100kW PV inverter.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.47-52
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• 2006

This paper proposes a novel low-power $32bit\times32bit$ multiplier for deep submicron technologies beyond 130nm. As technology becomes small, static power due to leakage current significantly increases, and it becomes comparable to dynamic power. Recently, shutdown method based on MTCMOS is widely used to reduce both dynamic and static power. However, it suffers from severe power line noise when restoring whole large-size functional block. Therefore, the proposed multiplier mitigates this noise by shutting down and waking up sequentially along with pipeline stage. Fabricated chip measurement results in $0.35{\mu}m$ technology and gate-transition-level simulation results in 130nm and 90nm technologies show that it consumes $66{\mu}W,\;13{\mu}W,\;and\;6{\mu}W$ in idle mode, respectively, and it reduces power consumption to $0.04%\sim0.08%$ of active mode. As technology becomes small, power reduction efficiency degrades in the conventional clock gating scheme, but the proposed multiplier does not.

• Fire Science and Engineering
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• v.24 no.4
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• pp.116-122
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• 2010

The fire protection system of nuclear power plants shall be designed, constructed and operated, through a defense-in depth criterion to suppress the leakage of radioactivity to the outside and to allow the safety shutdown function when a fire occurs. In order to achieve these purposes, most of countries abroad operating the nuclear power plants keep up the integrated regulations, however we have two guidelines, the fire protection service act and the nuclear energy act, as mandatory requirements to apply to the fire protection systems in nuclear power plants. It has shown that USA, Canada and Japan which have long experience in operating nuclear power plants have regulations integrated technically for fire protection system of nuclear power plants. It is proposed that the things once verified the risk analysis of the fire hazard by the nuclear law in the design for fire suppression system in plants should be authorized by the fire protection service act as an exception.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.839-846
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• 2007

In this paper, the first attempt to design a novel structure of dual-band feedforward linear power amplifier(FFW LPA) was presented. Up to now, primary technical difficulty has been the extension of the conventional signal canceller to the dual-band operation. Therefore, we propose the design technique of the dual-band equal group delayed carrier canceller, the dual-band equal group delayed intermodulation distortion(IMD) canceller and the dual-band FFW LPA. The operation frequency bands of the implemented dual-band FFW LPA are digital cellular($f_0=880$ MHz) and IMT-2000($f_0=2.14$ GHz) band, which are separated about 1.26 GHz. With the high power amplifier of 120 W PEP for commercial base-station application, IMD cancellation loop shows 20.45 dB and 25.04 dB loop suppression at each band of operation for 100 MHz. From the adjacent channel leakage ratio(ACLR) measurement with CDMA IS-95A 4FA and WCDMA 4FA signal, we obtained 16.52 dB improvement at the average output power of 41.5 dBm for digital cellular band, and 18.59 dB improvement at the average output power of 40 dBm for IMT-2000 band simultaneously.

• Fire Science and Engineering
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• v.30 no.6
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• pp.48-56
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• 2016

A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.681-689
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• 2010

We will demonstrate a novel topology for the feedforward amplifier. This amplifier does not use a delay element thus providing an efficiency enhancement and a size reduction by employing a distributed element negative group delay circuit. The insertion loss of the delay element in the conventional feedforward amplifier seriously degrades the efficiency. Usually, a high power co-axial cable or a delay line filter is utilized for a low loss, but the insertion loss, cost and size of the delay element still acts as a bottleneck. The proposed negative group delay circuit removes the necessity of the delay element required for a broadband signal suppression loop. With the fabricated 2-stage distributed element negative group delay circuit with -9 ns of total group delay, a 0.2 dB of insertion loss, and a 30 MHz of bandwidth for a wideband code division multiple access downlink band, the feedforward amplifier with the proposed topology experimentally achieved a 19.4 % power added efficiency and a -53.2 dBc adjacent channel leakage ratio with a 44 dBm average output power.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.1009-1014
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• 2012

This paper has proposed a 2,500 MHz ~ 2,570 MHz 0.13-${\mu}m$ CMOS RF front-end transmitter for LTE-Advanced systems. The proposed RF front-end transmitter is composed of a quadrature up-conversion mixer and a driver amplifier. The measurement results show the maximum output power level is +6 dBm and the suppression ratio for the image sideband and LO leakage are better than -40 dBc respectively. The fabricated chip consumes 36 mA from a 1.2 V supply voltage.