• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.2
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• pp.82-87
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• 1985

The performance comparison method against ground clutter, when the trasnfer function of MTI filter or integrator is given, is considered for the MTI signal processors using a constant PRF. The MTI signal processors are modelled as the transversal filters, and the ground clutter power density spectrum as Gaussian type and the performance of the MTI signal processors are compared by calculating the MTI improvent factors. The MTI imrpovement factors versus normalized spectral width is depicted as examples for the MTI filters, the integrator using Hanning weighting function and the cascading of the two.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.144-147
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• 1985

In electricity industry, the improvement of load factor by flattening of load has been considered to be more important than any other tasks and has received wide concern and interest. Especially while annual peak load had occured early evening in winter during past decades, but we found the trend has changed so that annual peak load occured during the daytime in summer since1981 The useful practicing methods of this load management ale as follows; 1. Inducing of midnight load by thermal storage water heating 2. Seasonal differential rates. 3. Revising the peak load priceing (Time-of -use) It seems hard to expect that load research can be carried out in a short time, and we all have to exert outselves continuously to provide efficient load management method without wasting resources.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.34-39
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• 2004

Fluorescent lamp operated at high frequency by the electronic ballast provide ballasts like unnoticed flicker effect and higher luminous efficiency. This paper presents analysis of Half-Bridge type resonant inverter for Fluorescent lamp drive for stable characteristic and life improvement of lamp operated at high frequency. Also, it has described an electronic ballast design with the capability of high PF (Power Factor) and low THD (Total Harmonic Distortion). The validity of designed electronic ballast circuit is confirmed by simulation and experimental results. The Designed electronic ballast is implemented successfully on 32W Fluorescent lamp system.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.728-730
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• 1993

This paper describes a simple but effective V/F control method for energy saving of a special-purpose Induction motor driven by PWM inverter. The proposed method is based on efficiency control with no speed sensor that the V/F patterns could be changed to load variations. The experimental results shows great improvement of both efficiency and power factor and usefulness of the method.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.37-47
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• 2012

Engaged number in the construction industry is 45 percentage level against to manufacturing industry. And Induction -factor of Production is much the same to mfg. field, Value added Induction-factor is more higher than manufacturing industry, therefore we research again about workers' inferior working & personal life condition in our society in order to they feel happiness their life with pride for the job construction occupation. So construction companies & government will be contribute to strengthen their phase & to achieve more higher level of construction working culture for elevate competitive power. We have to prepare the basis to turn to the qualitative construction businesses by break away from only the amount of work volume in company with the system of workers' self-conceit on the ground of professional education/training, qualification system, social insurance benefits, working condition improvement, stable job. Our nations does not feel well-being senses, only 25 class level in the 30 countries of OECD. We draw the questions at issue with slough off old customs in order to qualitative improvement for profession & self-contentment of construction workers, and present the useful plan to contribute to international competitiveness with our construction firms in the globalize construction field under Government's & company's policy.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.2
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• pp.128-137
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• 1999

Recently the pelionnance of CO2 arc welding machine has been advanced significantly through the adoption of i invelter circuit topology. which made it possible to improve welding perfonnances such as spatter generation and bead s state. But the conventional inverter arc welding machine generates constant output voltage which cause much spatter g generation dUling short-circuit and arc start time because it is unable to control output current instantaneously. So this p paper representes wavefCnm controlled inverter arc welding machine which control the wavefonn of welding current and t thus to suppress the spatter generation. And the system designed in this paper is the digital controller using single chip m microprocessor of 80C196KC. As a result of perfonnance test for this system, the spatter generation is reduced and s shOlt-circuit time period is stabilized compared to conventional one. And more by using switched mode rectifier for A AC/DC power convelter. unity power factor is maintained and low order halmonic spectrum is supressed.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.128-137
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• 2000

A study has been made to investigate the effects of hot isostatic pressing(HIPing) on the microstructure and high temperature fatigue lives of the IN738LC, Ni-base superalloy used in turbine blades, with emphasis on the elimination of casting microporosity and fatigue damage through HIP treatments. Microstructure was observed using OM, SEM and the fatigue life was investigated with rotate bending fatigue tester. The results show that the fatigue lives of properly HIP-processed specimens could be extended be extended by a factor of about sixty. In contrast, no comparable life improvement was achieved with heat treatment only. The repetitive HIP treatment was shown to be very effective as a means of rejuvenating the fatigue life of intentionally fatigue-damaged IN738LC by restoration of the initial alloy microstructure and additional removal of fine casting defects which remained in the HIP-processed material.

• Journal of Korea Port Economic Association
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• v.27 no.2
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• pp.111-136
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• 2011

This article aims to reveal the relative influences to the Brand Power and Performance of Factors that comprise the port brand assets in order to control and manage the ports. And also this Paper want to suggest the useful strategies and implications for the improvement of Brand Power by comparing the level of brand competitiveness of Incheon Port with those of other Korean ports that are in competitive relation. In this research we can find out that the components of port brand asset are awareness level, image, service quality, and satisfaction of relation. And among those 4 factors, recognition level and satisfaction of relation are very significant relation factors for the loyalty in Incheon Port. In comparison study between Incheon and Pyungtack Ports, satisfaction of relation is revealed as especially significant factor for the customers that show highly effective management performances and we can find that, in Busan Port, image and service quality are significant as well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.640-646
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• 2017

A GEN TEST of the auxiliary power unit of a T-50 series aircraft is performed as part of the operational test of its emergency power system on the ground before flight. At this time, the auxiliary power unit should be automatically turned off via the response signal of the ECU when power is not normally supplied to the emergency power system. If the correct operation of the emergency power system cannot be confirmed on the ground, it is not possible to proceed with the flight. This kind of defect is a major factor causing the operation rate of the aircraft to be decreased. The defect code identified by the ECU was confirmed as a defect in the inverter. However, the same defect was found after replacing the inverter. This report presents an improved method of identifying the cause of the defect by analyzing the response characteristics of the ECU and emergency power system and allows the ECU to be recognized as the cause of the defect if the inverter does not generate a voltage within a certain time. Also, the application of the improved method confirmed that it can satisfy the output request time of the emergency power system and effectively prevent the auto-shutdown of the auxiliary power unit.

• Journal of Climate Change Research
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• v.4 no.4
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• pp.349-358
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• 2013

In this study, the newest technology available to reduce GHG emissions, which can be applicable in energy industries of the future that has large reduction obligations by energy target management and large intensity of GHG emissions, has been investigated by searching the technical characteristics of each technology. The newest technology to reduce GHG emissions in the field of power generation and energy can be mainly classified into the improvement of efficiency, CCS, and gas combined-cycle technology. In order to improve the reliability of the GHG emission factor obtained from the investigation process, it has been compared to the technology-specific GHG emission factor derived from the estimated amount of emissions. Then the GHG abatement measures, using the derived estimation of factor, by using the newest technology to reduce GHG emissions have been predicted. As a result, the GHG reduction rate by technology of CCS development has been expected to be the largest more than 30%, and the abatement rate by technology of coal gasified fuel cell and pressurized fluidized-bed thermal power generation has been showed more than 20%. If the effective introduction of the newest technology and the study of its characteristics is continued, and properly applied for future GHG emissions, it can be prospected that the national GHG reduction targets can be achieved in cost-efficient way.