• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.319-323
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• 1996

A new steel-making process, strip-casting, is introduced. The strip-casting is a new technique making the thin steel strip from the molten steel directly without resorting to repetitive reheating and hot-rolling required in a conventional steel-making method. This paper derives the mathematical model of strip caster, proposes a control strategy for stable startup operation and a fuzzy decision making rule for automatic control mode change in strip-casting process.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.427-427
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• 2012

Ferroelectric-gate field effect transistor based memory using a nanowire as a conducting channel offers exceptional advantages over conventional memory devices, like small cell size, low-voltage operation, low power consumption, fast programming/erase speed and non-volatility. We successfully fabricated ferroelectric nonvolatile memory devices using both n-type and p-type Si nanowires coated with organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] via a low temperature fabrication process. The devices performance was carefully characterized in terms of their electrical transport, retention time and endurance test. Our p-type Si NW ferroelectric memory devices exhibit excellent memory characteristics with a large modulation in channel conductance between ON and OFF states exceeding $10^5$; long retention time of over $5{\times}10^4$ sec and high endurance of over 105 programming cycles while maintaining ON/OFF ratio higher $10^3$. This result offers a viable way to fabricate a high performance high-density nonvolatile memory device using a low temperature fabrication processing technique, which makes it suitable for flexible electronics.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.3
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• pp.246-254
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• 2018

In this study, we developed a thermoelectric generation system for coastal fishing boats that allows for a high-density arrangement of thermoelectric modules, verified the improvement in performance by conducting comparative analysis between field test results and results from previous studies. The developed thermoelectric generation system was installed in a 3-ton gill-netter to analyze the engine revolutions per minute and energy production per day for each fishing process over a period of 20 days. From the experimental results, the maximum electric energy generated was 207.1 Wh, the minimum was 53.93 Wh and the average electric energy was 129.98 Wh. In accordance with the increasing of the engine r.p.m., the maximum electric production was 183 W at 1,500 r.p.m. It was approximately 80.5% of designed capacity, 227.2 W. Considering the result in the earlier research was 50.7% of designed capacity, 115.8 W. It was improved by 30% compared to the earlier one. The fishing operation was classified as departure, fishing and arrival. From the result on production analysis of electric energy, the composition of energy was 63% in fishing, 19.5% in departure and 17.5% in arrival. The electric energy production per unit hour was 42.8% in arrival, 32.9% in departure and 24.3% in fishing.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4514-4521
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• 2022

In this study, the effects of heat and radiation on the degradation behaviour of fluoroelastomer under simulated normal operation and a severe accident environment were investigated using sequential testing of gamma irradiation and thermal degradation. Tensile properties and Shore A hardness were measured, and thermogravimetric analysis was used to evaluate the degradation behaviour of fluoroelastomer. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the structural changes of the fluoroelastomer. Heat and radiation generated in nuclear power plant break and deform the chemical bonds, and fluoroelastomer exposed to these environments have decreased C-H and functional groups that contain oxygen and double bonds such as C-O, C=O and C=C were generated. These functional groups were formed by auto oxidation by reacting free radicals generated from the cleaved bond with oxygen in the atmosphere. In this auto oxidation reaction, crosslinks were generated where bonded to each other, and the mobility of molecules was decreased, and as a result, the fluoroelastomer was hardened. This hardening behaviour occurred more significantly in the severe accident environment than in the normal operation condition, and it was found that thermal stability decreased with the generation of unstable structures by crosslinking.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.43-47
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• 1999

In this paper, we describe the configuration of the KITSAT-3 image data receiving, archiving, processing and distribution system in operation. Following the low-cost and software-based design concept, the whole system is composed of three PCs : two for data receiving, archiving and processing which provide a full dual-redundant configuration and one for image catalog browsing which can be accessed by public users. Except that receiving and archiving PCs have serial data ingest boards plugged in, they are configured by general peripherals. This basic and simple hardware configuration made it possible to show that a very low cost system can support a full ground operation for the utilization of high-resolution satellite image data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.4
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• pp.727-732
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• 2017

This paper describes the dynamic characteristics depending on installation condition between a pantograph and an OCL (Overhead Contact Line) on a new high speed line in Korea. The current collection performance between the pantograph and the OCL was tested during train operation from Suseo to Jije stations. The current collection performance is evaluated based on the duration of an arc by using an arcing measurement system. The system consists of an optical sensor for measuring the duration of an arc and a camera for monitoring current collection performance. An arcing duration is defined as a percentage of arcing in international standards. This test aims to analyze the locations of repetitive arcing depending on installation conditions of OCLs on a new high speed line in order to use the result as reference data for correct construction and maintenance.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.478-489
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• 2013

The controllability and stability of power systems can be increased by Flexible AC Transmission Devices (FACTs). One of the FACTs devices is Interline Power-Flow Controller (IPFC) by which the voltage stability, dynamic stability and transient stability of power systems can be improved. In the present paper, the convenient operation and control of IPFC for transient stability improvement are considered. Considering that the system's Lyapunov energy function is a relevant tool to study the stability affair. IPFC energy function optimization has been used in order to access the maximum of transient stability margin. In order to control IPFC, a Brain Emotional Learning Based Intelligent Controller (BELBIC) and PI controller have been used. The utilization of the new controller is based on the emotion-processing mechanism in the brain and is essentially an action selection, which is based on sensory inputs and emotional cues. This intelligent control is based on the limbic system of the mammalian brain. Simulation confirms the ability of BELBIC controller compared with conventional PI controller. The designing results have been studied by the simulation of a single-machine system with infinite bus (SMIB) and another standard 9-buses system (Anderson and Fouad, 1977).

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.2
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• pp.113-120
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• 2016

The necessity of maritime sector for continuous management, accurate and update location information such as seabed shape and location, research on airborne LiDAR bathymetry surveying techniques are accelerating. Airborne LiDAR systems consist of a scanner and GPS/INS. The location accuracy of 3D point data obtained by a LiDAR system is determined by external orientation parameters. However, there are problems in the synchronization between sensors should be performed due to a variety of sensor combinations and arrangement. To solve this issue, system calibration should be conducted. Therefore, this study evaluates the system verification methods, processes, and operation techniques.

• Journal of Semiconductor Engineering
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• v.1 no.1
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• pp.38-45
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• 2020

With the recent emergence of foldable electronic devices, interest in flexible organic memory is significantly growing. There are three types of flexible organic memory that have been researched so far: floating-gate (FG) memory, ferroelectric field-effect-transistor (FeFET) memory, and resistive memory. Herein, performance parameters and operation mechanisms of each type of memory device are introduced, along with a brief summarization of recent research progress in flexible organic memory.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.spc
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• pp.1-8
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• 2023

To investigate the national science and technology policy direction in the field of construction machinery, an analysis was conducted on projects selected as national research and development (R&D) initiatives by the government. Assuming that the project titles contain key keywords, text mining was employed to substantiate this assumption. Project information data spanning nine years from 2014 to 2022 was collected through the National Science & Technology Information Service (NTIS). To observe changes over time, the years were divided into three-year sections. To analyze research trends efficiently, keywords were categorized into groups: 'equipment,' 'smart,' and 'eco-friendly.' Based on the collected data, keyword frequency analysis, N-gram analysis, and topic modeling were performed. The research findings indicate that domestic government R&D in the construction machinery field primarily focuses on smart-related research and development. Specifically, investments in monitoring systems and autonomous operation technologies are increasing. This study holds significance in analyzing objective research trends through the utilization of big data analysis techniques and is expected to contribute to future research and development planning, strategic formulation, and project management.