• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.67-76
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• 1989

Although the standard 2-CR network filter, one of the filters used for measuring surface roughness, is being used widely in the field of industry it possesses a weak point of causing Phase-distortion when the wavelength is passing through. Phase-corrected filter is used for eliminating these phase-distortion and the difference of phase characteristics between these two filters is thought to have considerable amount of effect on the surface roughness value. Moveover, the definition on this is as yet unclear. Therefore, the Rt and Rz value, obtained when the wavelength are passed through the standard and phase-corrected filters from the same random machine-processed surface, and its standard deviation are compared and experimented in this paper. Also, the ratio of relative bearing curve complying to the phase characteristics of these two filters are acquired. As a result, the use of phese-corrected filter is appropriate in experiments where the form of wavelength is important, and the standard deviation on the same experimented values appeared greater with when using the standard filter. The rate of relative bearing curve became greater as .lambda.$_{c}$, the cut-off value of filter, became smaller.r.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.224-227
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• 2016

This paper proposes a design of W-band mm-wave wideband monopulse comparator using waveguide structure for applications. The main idea of proposed design is to combine a self-compensating phase shifter on $90^{\circ}$ hybrid for wideband $180^{\circ}$ hybrid. Using multiple conventional phase shifters, because of their narrow-band characteristics, tends to restrict working bandwidth of system including antennas. Proposed comparator could relieve the problem since it applies the self-compensating phase shifter. The comparator has waveguide structure so it shows excellent characteristic in loss. It also show wideband characteristic in amplitude and phase response between ports.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.261-265
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• 2005

This paper describes the DC-DC Converter for Ancillary Power Supply in Hybrid Electric Vehicle. DC-DC Converter is used for charging 12V auxiliary battery supplying electric power to head ramp, audio, ECU etc in automobiles. used DC-DC Converter Topology is PS-ZVS FB(Phase Shifted Zero Voltage Switching Full-Bridge) to reduce switching loss and EMI noise induced by high frequency operating condition. And For easy compensation and stable system response characteristic, current mode control method including slope compensation is employed. Constant current / constant voltage charging control method guarantee stable electric charging of auxiliary battery. Simulation toll PSIM6.0 is used for initial circuit parameter settings and H/W debuging. Thermal problems of Switching components in DC-DC Converter is improved by using Thermo Tracer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2261-2266
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• 2009

A novel adaptive phase calibration method is proposed for nonlinear amplifiers. Based on the adaptive process of simple phase vector calculations, the AM/PM distortion can be significantly reduced for various input power. The performance of the proposed method is evaluated for up to 80 % improvements in AM/PM distortions, compared with the distortion of a conventional amplifier. Moreover, by means of an additional envelope-compensation technique, the improvement of the adjacent channel power ratio (ACPR) is presented.

• Knowledge Management Research
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• v.22 no.3
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• pp.1-16
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• 2021

For the effective responsiveness toward Management Evaluation System of Public Institutions and continuous development as a public corporation, internal performance management is essential. In this study, the effect of employees' perceptions on the effectiveness and acceptability of the internal performance evaluation system on organizational commitment was tested, and we attempted to find implications for efficient performance management. For this purpose, we obtained valid responses from 208 members of A corporation and the hypotheses were verified through multiple regression analysis. As a result of the analysis, 'performance evaluation effectiveness' and 'performance evaluation acceptability' for internal performance evaluation had positive effects on 'organizational commitment'; however, the effect of 'differential performance compensation' on 'organizational commitment' was not significant. Also, among the control variables, 'age' and 'job group' were found to have a negative (-) effect on 'organizational commitment'. To derive more generalized conclusion, other researches using bigger samples are needed.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.58-71
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• 2019

The purpose of this study is to explore the multi-dimensionality and the differences of the career success that is revealed by the employee's perception. In order to fulfill the research purpose, LDA topic modeling has applied to extract latent topics of career success from 126 Korean employees' open-end survey questionnaires. The extracted latent topics are social recognition, continuing service within an organization, expertise, financial rewards, and pursuing personal meaning. The occurrence probability of each topic was different by individual characteristics such as gender, education, position. Study findings showed there is multi-dimensionality in career success, and there are differences of topic occurrence probability by demographic characteristics. Additionally, this study showed how to apply the recently developed machine learning approach in order to reduce the researcher's bias by adapting the LDA topic modeling to the qualitative open-ended survey data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6247-6253
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• 2015

This paper presents the transient-response improved LDO regulator based on parallel error amplifiers. The proposed LDO regulator consists of an error amplifier (E/A1) which has a high gain and narrow bandwidth and a second amplifier (E/A2) which has low gain and wide bandwidth. These amplifiers are in parallel structure. Also, to improve the transient-response properties and slew-rate, some circuit block is added. Using pole-splitting technique, an external capacitor is reduced in a small on-chip size which is suitable for mobile devices. The proposed LDO has been designed and simulated using a Megna/Hynix $0.18{\mu}m$ CMOS parameters. Chip layout size is $500{\mu}m{\times}150{\mu}m$. Simulation results show 2.5 V output voltage and 100 mA load current in an input condition of 2.7 V ~ 3.3 V. Regulation Characteristic presents voltage variation of 26.1 mV and settling time of 510 ns from 100mA to 0 mA. Also, the proposed circuit has been shown voltage variation of 42.8 mV and settling time of 408 ns from 0 mA to 100 mA.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.528-531
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• 2007

This paper presents development of a 4-inch WVCA OCB (Optical Compensated Bend)-mode display panel. The developed panel has a built-in circuit of the LTPS (low temperature poly-Si)-integrated gate driver circuit with the function of black data insertion. The function of black data insertion makes it possible to realize rapid response time of 4ms and wide viewing angle of $160^{\circ}$. We also applied the RGBW pixel structure for the brighter image with relatively low power consumption. The developed panel showed improved optical efficiency and driving capability of stable image quality for OCB mode. We developed high efficiency OCB-mode panel with built-in integrated gate driver circuit using LTPS on panel without any external driver IC.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.97-102
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• 1995

A questionare survey was performed to investigate the citizen's attitude concerning waste treatment facilities. Most people recognized the seriousness of the waste treatment problem and think that more composting facilities should be built. People dislike most the landfill facility, followed by the nightsoil treatment facility, the incineration facility and the composting facility. Most people answered that the disirable distance from their house to the treatment facility should be farther than 4km for the landfill facility, farther than 2km for incineration and composting facilities and farther than 1km for the wastewater treatment plant. Most people want moving cost+land price+inconvience suffering cost (amount equal to the land prize+building prize) for their retrieval. About 30% of people answered that they will not accept any waste treatment facility even though it is perfect.

• The Journal of the Acoustical Society of Korea
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• v.8 no.4
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• pp.29-38
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• 1989

Detection of an underwater target by acoustic wave raises various difficulties due to unpredictable noise interference which originates from clutter, reverberation, and variations of medium characteristics with time and location. The SNR and the range resolution of conventional SONAR systems using a matched filter are generally poor, since the latter is optimum only in the additive white noise case. Furthermore, it cannot compensate for variations of the detection level which are responsible for the resultant detection errors. In this paper, the unpredictable interferences are compensated for by using an adaptive filter. It recursively estimates the channel impulse response based on the received echo signal. In the low noise environments, the estimated impulse response is close to the true one, providing a good range resolution, and a matched filter is used subsequently for the purpose of detection. It is shown through computer simulation that good performance can be achieved via the two steps of filtering. Also, the detection level remains unchanged without any additional provisions. Finally, we present the characteristics of the employed adaptive filter parameters.