• 한국정보통신학회논문지
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• 제6권6호
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• pp.863-872
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• 2002

Real-time(RT) object-oriented(00) distributed computing is a form of RT distributed computing realized with a distributed computer system structured in the form of an object network. Several approached proposed in recent years for extending the conventional object structuring scheme to suit RT applications, are briefly reviewed. Then the approach named the TMO(Time-triggered Message-triggered Object) structuring scheme was formulated with the goal of instigating a quantum productivity jump in the design of distributed time triggered simulation. The TMO scheme is intended to facilitate the pursuit of a new paradigm in designing distributed time triggered simulation which is to realize real-time computing with a common and general design style that does not alienate the main-stream computing industry and yet to allow system engineers to confidently produce certifiable distributed time triggered simulation for safety-critical applications. The TMO structuring scheme is a syntactically simple but semantically powerful extension of the conventional object structuring approached and as such, its support tools can be based on various well-established 00 programming languages such as C++ and on ubiquitous commercial RT operating system kernels. The Scheme enables a great reduction of the designers efforts in guaranteeing timely service capabilities of application systems.

• 한국정보통신학회논문지
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• 제17권3호
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• pp.540-545
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• 2013

Fractional 푸리에변환(Fractional Fourier Transform : FRFT)은 기존의 푸리에 변환의 일반화된 형태로서, 양자역학분야에서 처음 소개되었다. FRFT가 가지는 시간-주파수 영역에서의 단순하면서도 유용한 특성으로 인하여, 지금까지 소나 및 레이더 신호처리 분야에서 많은 연구결과들이 발표되었으며, 푸리에 변환을 활용한 기존의 방법보다 우수한 연구결과를 보여 왔다. 본 논문에서는 LFM(Linear Frequency Modulation)신호들이 겹쳐져 수신되었을 경우에 이들 신호들을 검출하고 분리하기 위해 FRFT를 이용하였다. 실험결과 수신된 LFM 신호들을 FRFT 영역에서 효율적으로 검출하고 분리가 가능함을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.2134-2143
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• 2018

This work introduces a fault diagnosis method for transformer based on self-powered radio frequency identification (RFID) sensor tag and improved Hilbert-Huang transform (HHT). Consisted by RFID tag chip, power management circuit, MCU and accelerometer, the developed RFID sensor tag is used to acquire and wirelessly transmit the vibration signal. A customized power management including solar panel, low dropout (LDO) voltage regulator, supercapacitor and corresponding charging circuit is presented to guarantee constant DC power for the sensor tag. An improved band restricted empirical mode decomposition (BREMD) which is optimized by quantum-behaved particle swarm optimization (QPSO) algorithm is proposed to deal with the raw vibration signal. Compared with traditional methods, this improved BREMD method shows great superiority in reducing mode aliasing. Then, a promising fault diagnosis approach on the basis of Hilbert marginal spectrum variations is brought up. The measured results show that the presented power management circuit can generate 2.5V DC voltage for the rest of the sensor tag. The developed sensor tag can achieve a reliable communication distance of 17.8m in the test environment. Furthermore, the measurement results indicate the promising performance of fault diagnosis for transformer.

• 한국전기전자재료학회논문지
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• 제30권8호
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• pp.508-513
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• 2017

Ultraviolet (UV) photodetectors are used in various industries and fields of research, including optical communication, flame sensing, missile plume detection, astronomical studies, biological sensors, and environmental research. However, general UV detectors that employ Schottky junction diodes and p-n junctions have high fabrication cost and low quantum efficiency. In this study, we investigated the characteristics of materials used to manufacture UV photodetectors in a low-cost solution process that requires easy fabrication of flexible substrates. We fabricated p-type NiO and n-type ZnO substrates with wide band gap by the sol-gel method and compared the characteristics of substrates prepared under different spin-coating and heat-treatment conditions.

• Nuclear Engineering and Technology
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• 제41권9호
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• pp.1157-1170
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• 2009

A variety of Generation III/III+ reactor designs featuring enhanced safety and improved economics are being proposed by nuclear power industries around the world to solve the future energy supply shortfall. Nanofluid coolants showing an improved thermal performance are being considered as a new key technology to secure nuclear safety and economics. However, it should be noted that there is a lack of comprehensible design works to apply nanofluids to Generation III+ reactor designs. In this work, the review of accident scenarios that consider expected nanofluid mechanisms is carried out to seek detailed application spots. The Axiomatic Design (AD) theory is then applied to systemize the design of nanofluid-engineered nuclear safety systems such as Emergency Core Cooling System (ECCS) and External Reactor Vessel Cooling System (ERVCS). The various couplings between Gen-III/III+ nuclear safety features and nanofluids are investigated and they try to be reduced from the perspective of the AD in terms of prevention/mitigation of severe accidents. This study contributes to the establishment of a standard communication protocol in the design of nanofluid-engineered nuclear safety systems.

• Journal of information and communication convergence engineering
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• 제17권2호
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• pp.161-165
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• 2019

In this study, zinc tin oxide (ZTO) thin-film transistors are researched to observe the correlation between the barrier potential and electrical properties. Although much research has been conducted on the electronic radiation from Schottky contacts in semiconductor devices, research on electronic radiation that occurs at voltages above the threshold voltage is lacking. Furthermore, the current phenomena occurring below the threshold voltage need to be studied. Bidirectional transistors exhibit current flows below the threshold voltage, and studying the characteristics of these currents can help understand the problems associated with leakage current. A factor that affects the stability of bidirectional transistors is the potential barrier to the Schottky contact. It has been confirmed that Schottky contacts increase the efficiency of the element in semiconductor devices, by cutting off the leakage current, and that the recombination at the PN junction is closely related to the Schottky contacts. The bidirectional characteristics of the transistors are controlled by the space-charge limiting currents generated by the barrier potentials of the SiOC insulated film. Space-charge limiting currents caused by the tunneling phenomenon or quantum effect are new conduction mechanisms in semiconductors, and are different from the leakage current.

• Journal of Radiation Protection and Research
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• 제46권2호
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• pp.80-82
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• 2021

Dr. Haruyuki Ogino, a member of the Japan Health Physics Society (JHPS), was awarded the 2021 Bo Lindell Medal by the International Commission on Radiological Protection (ICRP). To commemorate this, the "Joint JHPS-KARP-ARPS program for young radiation protection (RP) scientists to discuss the future of RP" was organized via a web meeting system. First, Dr. Ogino gave a lecture, and then young researchers selected from each academic society made presentations on the future of RP. After the presentations by the three researchers, a free talk was held-young researcher groups of each country being active is a great opportunity to collaborate and exchange information. It was emphasized that the low awareness of knowledge related to radiation has been common to all of the participating countries. Thus, it is necessary to utilize communication via web technology, as done for this program, effectively. One of the biggest advantages for Asia and Oceania is that we do not have a significant time difference. The round-table discussion was concluded by expressing the hope of active exchange and development of young researchers in the future.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.220-223
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• 2008

A camera system for the satellite application performs the mission of observation by measuring radiated light energy from the target on the earth. As a development stage of the system, the signal level analysis by estimating the number of electron collected in a pixel of an applied CCD is a basic tool for the performance analysis like SNR as well as the data path design of focal plane electronic. In this paper, two methods are presented for the calculation of the number of electrons for signal level analysis. One method is a quantitative assessment based on the CCD characteristics and design parameters of optical module of the system itself in which optical module works for concentrating the light energy onto the focal plane where CCD is located to convert light energy into electrical signal. The other method compares the design\ parameters of the system such as quantum efficiency, focal length and the aperture size of the optics in comparison with existing camera system in orbit. By this way, relative count of electrons to the existing camera system is estimated. The number of electrons, as signal level of the camera system, calculated by described methods is used to design input circuits of AD converter for interfacing the image signal coming from the CCD module in the focal plane electronics. This number is also used for the analysis of the signal level of the CCD output which is critical parameter to design data path between CCD and A/D converter. The FPE(Focal Plane Electronics) designer should decide whether the dividing-circuit is necessary or not between them from the analysis. If it is necessary, the optimized dividing factor of the level should be implemented. This paper describes the analysis of the electron count of a camera system for a satellite application and then of the signal level for the interface design between CCD and A/D converter using two methods. One is a quantitative assessment based on the design parameters of the camera system, the other method compares the design parameters in comparison with those of the existing camera system in orbit for relative counting of the electrons and the signal level estimation. Chapter 2 describes the radiometry of the camera system of a satellite application to show equations for electron counting, Chapter 3 describes a camera system briefly to explain the data flow of imagery information from CCD and Chapter 4 explains the two methods for the analysis of the number of electrons and the signal level. Then conclusion is made in chapter 5.

• 한국융합학회논문지
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• 제12권12호
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• pp.1-18
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• 2021

ICT(Information Communication Technology)는 우리나라 경제 성장의 주요 동력이다. 우리나라는 세계 최고수준의 ICT 경쟁력을 보유하고 있으며, 이 경쟁력을 유지하기 위해 다수의 정책을 시행하고 있다. 성공적인 정책 시행을 위해서는 ICT 동향을 정확하게 파악하는 것이 중요하다. 따라서 본 연구에서는 빈도수 분석, 네트워크 분석, 기술 유형화를 기반으로 ICT 분야 핵심 기술 18개의 동향을 분석한다. 특히, 논문 분석을 통해 기술별 과학적 발전 정도를, 특허 분석을 통해 상용화의 정도를 알아본다. 그리고 두 분석 결과를 토대로 문서의 유형별로 나타난 동향을 비교 분석한다. 분석 결과, 인공지능과 가상현실은 과학적 발전을 지나 상용화가 활발히 이루어지는 동시에 연구도 이루어지고 있어 지속적인 발전이 기대되는 기술이며, 로봇, 블록체인, 차세대이동통신은 상용화 시작 단계로 시장의 현황 및 니즈 발굴이 필요하다. 반면, 양자컴퓨터, 체내삽입형디바이스는 아직 기초 연구 단계이며, 현 연구 상황에 대해 파악하고 앞으로의 지원 방향이 결정될 필요가 있다. 본 연구에서 수행된 ICT 동향 분석 결과는 ICT 분야 핵심 기술의 현황을 정확하게 이해하고 우리나라 정책의 향후 방향을 결정하는 기준으로 활용 가능할 것이다.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.677-682
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• 2015

본 논문에서는 일반적인 광시스템에서 항상 존재하는 잡음 및 외부로부터 더해지는 잡음이 광시스템의 수신기의 성능에 미치는 영향에 대하여 고찰하였다. 광전송시스템에서 광검출기가 1 이하의 양자효율을 갖는 경우를 고려하여 온-오프 키잉 전송시에 수신기의 수신 감도를 계산하였다. m이 50이상인 경우 표준에러확률을 유지하기 위한 광시스템의 수신기 감도가 300이하로 계산되어 m가 적은 경우에 비해서 저출력 시스템을 구성할 수 있음을 확인할 수 있었다. 그러나 이러한 값도 실제 시스템에서는 큰 부담이 되는 값이므로 보다 저출력 광원을 사용하는 경우를 고려하여 수신단에 전치증폭기를 설치한 경우에 대해서도 고려하였는데, 그림 3에서 보이는 바와 같이 보다 적은 출력을 갖는 광원을 사용해도 무방하다는 결과를 얻을 수 있었다.