• 한국전기전자재료학회논문지
• /
• 제30권8호
• /
• pp.508-513
• /
• 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
• /
• 제41권9호
• /
• pp.1157-1170
• /
• 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
• /
• 제17권2호
• /
• pp.161-165
• /
• 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
• /
• 제46권2호
• /
• pp.80-82
• /
• 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
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.220-223
• /
• 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
• /
• 제12권12호
• /
• pp.1-18
• /
• 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
• /
• 제16권1호
• /
• pp.677-682
• /
• 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.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.226-226
• /
• 2013

Si is a dominant solar material, which is the second most abundant element in the earth giving a benefit in the aspect in cost with low toxicity. However, the inherent limit of Si has an indirect band gap of 1.1 eV resulting in the limited optical absorption. Therefore, a critical issue has been raised to increase the utilization of the incident light into the Si absorber. The enhancement of light absorption is a crucial to improve the performances and thus relieves the cost burden of Si photovoltaics. For the optical aspect, an efficient design of a front surface, where the incident light comes in, has been intensively investigated to improve the performance of photon absorption. Lambertian light trapping can be attained when the light active surface is ideally rough to increase the optical length by about 50 compared to a planar substrate. This suggests that an efficient design may reduce thickness of the Si absorber from the conventional 100~300 ${\mu}m$ to less than 3 ${\mu}m$. Theoretically, a hole-array structure satisfies an equivalent efficiency of c-Si with only one-twelfth mass and one-sixth thickness. Various approaches have been applied to improve the incident light utilization in a Si absorber using textured structures, periodic gratings, photonic crystals, and nanorod arrays. We have designed hole and pillar structured Si absorbers. Four-different Si absorbers have been simultaneously fabricated on an identical Si wafer with hole arrays or pillar arrays at a fixed depth of 2 ${\mu}m$. We have found that the significant enhanced solar cell performances both for the hole arrayed and pillar arrayed Si absorbers compared to that of a planar Si wafer resulting from the effective improvement in the quantum efficiencies.

• 한국통신학회논문지
• /
• 제41권4호
• /
• pp.489-498
• /
• 2016

정보복제 및 도/감청이 기술적으로 불가능한 양자통신의 출현에도 불구하고, 일부 해커들의 부적절한 동기와 목적에 의한 사이버테러(cyber-terror)는 지속적으로 시도될 것으로 예상된다. 따라서 해킹의 주체인 해커들의 심리적 관점에 대한 연구의 중요성과 필요성이 더욱 커지고 있다. 본 연구는 Beebe & Clark(2006)의 연구를 보완하여, 탈선적 해킹에 관련된 해커들의 주요한 심리적 독립변수가 무엇인지 탐색하고, 그에 따른 해킹의도와 실제 해킹경험을 종속변수로 측정하였다. 본 연구의 결과로서, 해킹의도와 해커들의 타입을 구분해서 예측할 수 있는 모델을 도출하였으며, 이 결과는 향상된 사이버 보안을 위한 인적 관리에 응용할 수 있음을 제안하였다.

• 한국정보통신학회논문지
• /
• 제6권2호
• /
• pp.159-168
• /
• 2002

실시간 객체지향 분산 컴퓨팅은 객체 네트워크 형태에서 분산된 컴퓨터 시스템 구조와 관련 된 실시간 분산 컴퓨팅의 한가지 형태이다. 최근에 실시간 응용분야에 적합한 기존의 객체지향 시스템 구조를 확장한 몇 가지 의 구조가 제안되었다. 실시간 시뮬레이션 프로그램의 하나인 시간 및 메시지 트리거 객체지향 프로그램밍이 분산된 시간 트리거 시뮬레이션으로 설계될 수 있으며, 일반적이고 보편적인 설계 타입으로서 사용되고, 하나 의 실시간 시뮬레이션 패러다임으로 제안하였다. 실시간 객체지향 프로그램밍은 안전을 중요시하게 여기는 응용분야에 적용할 수 있으며, 실시간 운영체제 시스템 커널로서 객체지향 프로그램밍 언어인 비쥬얼 C++언어로 작성되었다. 응용 시스템에서 실시간 서비스를 보장하기 위한 설계자들의 노력을 현저하게 줄일 수 있는 장점을 가지고 있다.