• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.885-895
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• 1994

In this paper, we propose the one-Ampere conductor method which is able to calculate the flux distribution conceptually and easily, and the improved winding method which suppresses space harmonics of magnetormotive force and enhances the coefficient of utilization of primary iron core in tubular linear induction motor. We carry out no-load test to verify effectiveness of proposed method and analyze characteristics by finite element method. As a result, performances are improved and propriety of primary iron core is enhanced comparing with conventional model.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.147-154
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• 2000

This paper proposes an overmodulation strategy for space-vector PWM(SVPWM). The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation region. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. The practical implementation is simple and it is applied to improve an output voltage of SVPWM controlled AC Motor in the steady-state. The characteristic of the proposed strategy is confirmed by simulations and experiments for a V/F control of a induction motor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.527-533
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• 1998

An optimized PWM switching strategy for an induction motor voltage control is developed and demonstrated. Space vector modulation in voltage source inverter offers improved DC-bus utilization and reduced commutation losses, and has been therefor recognizedas the perfered PWM method, especially in the case of digital implementation. Three-phase invertor voltage control by space vector modulation consists of switching between the two active and one zero voltage vector by using the proposed optimal PWM algorithm. The prefered switching sequence is defined as a function of the modulation index and period of a carrier wave. The sequence is selected by suing the inverter switching losses and the current ripple as the criteria. For low and medium power application, the experimental results indicate that good dynamic response and reduced harmonic distortion can be achieved by increasing switching frequency.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2989-2994
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• 2008

The shopping center in underground passage for efficient space utilization is increased in urban area. This study describes operation characteristics of HVAC systems with ventilation and individual heating and cooling unit for shopping center in underground passage. In order to compare energy saving, thermal environment and installation space, etc., an integrated simulator with heat production and distribution system was designed and constructed. Energy delivery efficiency is improved over 20%, and energy saving of the hybrid system is calculated as over 30% compared to conventional all air type in the case of heating. And also the results showed that humidity decreased about $5{\sim}6%$, also characteristics of thermal control is improved over 34%.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.76-81
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• 2007

The shopping center in underground passage increased for efficient space utilization in urban area. This study describes operation characteristics of all air type and hybrid type with local ventilation and fan coil unit fixed to ceiling. In order to compare energy saving, thermal environment and installation space, etc., integrated simulator with heat production and indoor distribution system is designed and constructed. Energy saving of the hybrid system is calculated as over 30% compared to conventional all air type. And also the results showed that humidity decreased about 6%, also indoor thermal distribution is improved as temperature variation of around $1^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.801-807
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• 2008

Recently, CV, CN-CV and CNCV-W cable are used for HVDC transmission and distribution cable. However, XLPE which is used as insulation layer of power cable has thermosetting properties. It is very difficult to recycling. In this paper, we prepared HDPE/EVA film, which the blending ratio are 80:20, 70:30, 60:40, 50;50 respectively for the purpose of recycling. Main factor such as electric field distribution and its resistivity in insulation system affected on insulation performance and reliability for HVDC applications. Therefore, electric field distribution formed by space charge and characteristics of volume resistivity was currently investigated. We suggest the possibility of utilization for HVDC insulation layer from the results.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.243-248
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• 2002

The International Space Station (ISS) offers research opportunities for researchers in the field of remote sensing to conduct world-class activities in Low Earth Orbit. ISS provides the facilities to place and operate research experiments in a variety of fields, providing investigators opportunities to perform research and Earth observation. This paper is intended to give the reader an introduction to the ISS utilization and the capabilities for remote sensing research that are being implemented through the development of research facilities. We hope that reader will consider what kind of payloads could be developed to take advantage of facilities, and will consider proposing remote sensing research on the ISS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.4
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• pp.335-342
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• 2021

By using HLS when developing a communication system FPGA, HDL code can be automatically generated from a little modified C/C++ source code used for performance verification, which has the advantage of shortening the development period. In this paper, a method of designing a telemetry standard 106-17 LDPC decoder in C language is proposed using Xilinx's Vivado HLS, and by synthesizing Spartan-7 and Kintex-7 as target devices, throughput and FPGA utilization rate was compared.

• Journal of Environmental Science International
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• v.32 no.2
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• pp.89-97
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• 2023

The purpose of this study is to examine the possibilities of use as a factor of the water landscape in modern urban spaces such as parks and, apartments, through a case study of the concept, functions, and culture of moats in the East and West from ancient times to the Middle Ages. This study aimed to examine the concept, origin, and function of the moat as a theoretical consideration. Asian castles with moats, including those in Korea, China and Japan, and Western castles with moats in Britain, France, Belgium, and Germany were investigated and analyzed. By reflecting on these cultures and the functions of the moat in modern urban spaces and converting the environment damaged due to industrialization and urbanization into an eco-friendly and environment symbiotic city the quality of life can be improved, and sustainable development can be achieved. This study was conducted through a literature survey and field investigation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.157-159
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• 2023

In order to promote the historicity of Eoryongdo Lighthouse, which was designated as a lighthouse cultural heritage in August 2023, and to utilize it as a water-friendly space, the facilities were improved to maintain the function of the lighthouse smoothly, and the buildings were reinforced to utilize it as a water-friendly space. We want to inform the public of the historical value of the lighthouse and make every effort to ensure maritime traffic safety, which is the original role of the lighthouse.