• 전기의세계
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• v.25 no.6
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• pp.69-73
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• 1976

Thd idle channel noise on FDM-microwave communication system is increasing because of the up-grade to wide-band loading. The thermal noise on receiver of microwave radio is measured according to their channel slot frequencies, low, meddle and high slots on the base band, from 60 channels to 960 channels. And suggested a consideration for system engineering, to reduce the thermal noise from radio microwave receivers, so as to improve signal to noise ratio.

• Journal of Aerospace System Engineering
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• v.4 no.1
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• pp.27-31
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• 2010

The scope of this paper is to analyze the safety aspects of the Ka-band payload system which are associated with testing, transportation, integration, handling and storage. According to ESA philosophy and the ECSS-Q-40A "Space Product Assurance - Safety", safety hazard analysis of Ka band payload was performed. In this paper, it is indicated the requirements to be satisfied for eliminating, reducing, or controlling the hazards and by showing how they have been implemented in the COMS design. And it shows the safety hazard analysis result which has performed the analysis according to ESA document and also shows the potential hazard cause, potential effects, hazard grade and criteria resolution of Ka band COPS.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.3
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• pp.227-233
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• 2023

In this paper, to substitute the existing TWTA(Travailing Wave Tube Amplifier) component in small radar system, we developed the Ku band SSPA(Solid-State Power Amplifier) based on the fabrication of power MMIC (Monolithic Microwave Integrated Circuit) chips. For the development of the 500 W SSPA, the 40 W-grade power MMIC was designed by ADS(Advanced Design System) at Keysight company with UMS GH015 library, and was processed by UMS foundry service. And 70 W main power modules were achieved the 2-way T-junction combiner method by using the 40 W-grade power MMICs. Finally, the 500 W SSPA was fabricated by the wave guide type power divider between the drive power amplifier and power modules, and power combiner with same type between power modules and output port. The electrical properties of this SSPA had 504 W output power, -58.11 dBc spurious, 1.74 °/us phase variation, and -143 dBm/Hz noise level.

• Journal of the Korean Institute of Educational Facilities
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• v.21 no.1
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• pp.23-32
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• 2014

Aim of this research is suggesting a satisfied studying space for lecturer, student and curriculum by abstraction of improvement plan which based on investigation and analysis of the space that teacher is using in lecturer and study support facility in school which managed in 'Department system'. This research focused on analyse of teacher's laboratory, teacher's room, and common room in middle and high school which managed and designed by 'Department system' and registered on 'Seoul office of education' and designed in management of department system between 2009 and 2012. With these process, a conclusion of this research is as in the following. Firstly, plan of teachers' private place which is efficient and stable is required through to get out of module which can cover subject band and grade band. Secondly, we have to focus on size of teachers' convenience facilities for convenience or official usage, movement radius, and improvement of working environments. Thirdly, 'Subject type teachers' laboratory' which organized by teachers who teach same subject is more efficient than 'Task type laboratory' which organized by teachers who working on same task for management of school. In fourth, 'Task type teachers' laboratory' arranged regardless with teachers' class room to teach, and it makes lack of connectivity between teacher and class room.

• School Mathematics
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• v.14 no.4
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• pp.531-552
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• 2012

In December of 2009, General Guidelines of Curriculum Revised in 2009 was announced and research on corresponding mathematics curriculum revision has been initiated from that period. Finally, in August 2011, Mathematics Curriculum Revised in 2009 was announced. Based on the examination the backgrounds and the basic directions of revision newly reformed mathematics curriculum should be applied in math class effectively and efficiently. According to this purpose, this paper first of all finds out what are the major points or difficulties to be caused by managing 'Mathematics Curriculum Revised in 2009' according to the change of 'General Guidelines of Curriculum Revised in 2009'. They are i) the implementation of grade band system, ii) management of differentiated class, and iii) increasing or decreasing of 20% in math class hour. According to those three points to be changed and reinforced newly in new curriculum, this paper investigates the alternatives and policy of dealing with smoothly and efficiently those issues while solving the difficulties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.33-37
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.66-70
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• 2001

The partial discharge testing is widely used in diagnostic measuring technology because it gives low stress to power equipment which is undertaken tests. Therefore it is very useful method compare to previous destructive methods and effective diagnosis method in power system that requires on-line/on-site diagnosis. But partial discharges have very complex characteristics of discharge pattern, so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated system is manufactured and HFPD occurred from those simulator is measured with broad-band antenna in real time, the degradation grade of system is analyzed through produced patterns in simulated target according to the AI/statistics processing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05a
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• pp.18-22
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• 2000

The partial discharge testing is widely used in insulation property measurement because it gives low stress to high voltage equipment which is undertaken tests. Therefore it is very useful method compare to previous destructive methods and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05a
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• pp.29-32
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• 2000

The partial discharge testing is widely used in insulation property measurement because it gives low stress to high voltage equipment which is undertaken tests. Therefore it is very useful method compare to previous destructive methods and effective diagnosis method in power transformer that requires on-line & on-site diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and PD/HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• School Mathematics
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• v.15 no.4
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• pp.759-783
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• 2013

Both curriculum and textbooks play an important role in the process of didactical transposition from mathematics as a science to school mathematics. The 2009 revised national curriculum for mathematics introduced the system of grade-band, so its achievement criteria for mathematical contents tend to be addressed more and less generally in the curriculum. We need to investigate whether the achievement criteria were applied meaningfully in elementary textbooks for mathematics. This study aims to recognize the connection between the curriculum and the textbooks and make a suggestion for composing the following curriculum and its textbooks. To do this, we analyzed the mathematics textbooks for 1~2 grades in relation to the mathematical contents as per reconstructed one of curriculum achievement criteria, the mathematical terms and symbols, and the mathematical processes -mathematical problem solving, mathematical reasoning, mathematical communication. Based this analysis, futhermore, this study includes some didactical discussions and implications for development of mathematics textbooks in 3~4 and 5~6 grade-bands.