• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.665-670
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• 2004

This paper reviews the latest studies of the expander cycle Air Turbo Ramjet engine (ATREX) conducted in JAXA. First, a system analysis including the vehicle and trajectory was conducted to optimize the engine cycle and turbo-machine configuration. We selected the precooled turbo-jet cycle for a prototype engine using the near term technologies. Second, a system ground-firing test was conducted to verify a defrosting system for the precooler. Methanol injection with its particles atomization could compensate 80 % of pressure loss caused by the frost. Thirdly, a feasibility of carbon/carbon composites for the engine components was investigated by making complex shapes such as a heat exchanger and a plug nozzle. Basic technologies on the gas leakage, the junction and bonding were also studied. The end of the paper, some basic studies such as wind tunnel tests of a new type air inlet and a plug nozzle are described.

• 전자통신동향분석
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• 제39권5호
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• pp.1-11
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• 2024

Recent advancements in artificial intelligence (AI) across diverse sectors have been widely supported by developments in AI semiconductors, with NVIDIA graphics processing units leading the market. However, concerns over market diversity and high energy consumption of AI workloads have prompted the development of next-generation AI semiconductors toward improving performance and energy efficiency. We discuss the latest trends in AI semiconductor and compiler technologies, both domestically and internationally. Key local companies, such as SAPEON, Rebellions, and Furiosa AI, and overseas giants, such as Google, Meta, and Tesla, are innovating in this field. Moreover, compiler technologies, such as MLIR, TVM, and XLA, are crucial for optimizing the performance of AI solutions across hardware platforms. Such developments are essential for enhancing AI applications and demand active research. This study offers insights into the current and future landscape of AI semiconductors and compilers, and it provides a foundation for future technological strategies in the AI industry.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.7-11
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• 2017

This paper describes a design concept of NPC1 power stack for 1500VDC megawatt level solar inverter. This stack uses three latest half-bridge IGBT modules with highest power density and operation junction temperature, which enable realization of power level beyond 1MW without paralleling. Critical design concept on loop inductance is explained. Dynamic characteristics are verified by double-pulse test. Thermal characteristics and output power limits are verified by thermal test. Temperature-sensitive component on PCB as output power constraint is identified. Different PCB repositioning solutions are tested to give the overall output power thermal derating curves, which enable output power of 1.15MW at $T_A=55^{\circ}C$ with $15^{\circ}C$ thermal margin. The power stack characteristic and performance change under different thermal environment is further analyzed.

• 한국콘텐츠학회논문지
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• 제18권10호
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• pp.443-452
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• 2018

최근 들어 지식재산권의 확보는 기업의 기술 경쟁력 확보를 위해 점점 더 중요하게 되었다. 특히 특허는 기업의 핵심 기술 및 요소 기술을 포함하고 있기 때문에 특허 분석을 통한 기업 가치 측정 및 경쟁 기술 분야 분석 등의 연구가 활발히 진행되고 있다. 국제특허분류(IPC)를 기반으로 다양한 특허 분석 연구가 진행되었으나, IPC는 최신의 기술 분야를 포함하고 있지 않으며 기술의 상세 분류가 충분하지 않아 기술 분류 정확도가 낮아진다. 이를 보완하기 위해 최신의 기술 분야를 포함하고 상세한 기술 분류를 위한 선진특허분류(CPC)가 개발되었으나 이러한 특징을 고려한 특허 분석 연구가 아직 미흡하다. 본 논문에서는 CPC의 상세 분류체계를 이용하여 특허에 포함된 기술 분류 분석 모델을 제안한다. CPC의 상세 분류체계간의 연관관계 중요도 및 효율성을 고려하여 출원인의 특허를 분석하여 핵심 기술 분류 추출을 통해 기존 IPC 기반의 방법보다 상세하고 정확한 분석이 가능하다. 기존의 IPC 기반의 특허 분석 방법과 비교 평가를 통해 제안 모델이 출원인의 핵심 기술 분류를 분석함에 있어 더 좋은 성능을 보임을 확인하였다.

• International Journal of Computer Science & Network Security
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• 제22권9호
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• pp.43-50
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• 2022

For high-quality education of the modern generation of students, forms of organizing the educational process and the latest methods of obtaining knowledge that differ from traditional ones are necessary. The importance of multimedia teaching tools is shown, which are promising and highly effective tools that allow the teacher not only to present an array of information in a larger volume than traditional sources of information, but also to include text, graphs, diagrams, sound, animation, video, etc. in a visually integrated form. Approaches to the classification of multimedia learning tools are revealed. Special features, advantages of multimedia, expediency of use and their disadvantages are highlighted. A comprehensive analysis of the capabilities of multimedia teaching tools gave grounds for identifying the didactic functions that they perform. Several areas of multimedia application are described. Multimedia technologies make it possible to implement several basic methods of pedagogical activity, which are traditionally divided into active and passive principles of student interaction with the computer, which are revealed in the article. Important conditions for the implementation of multimedia technologies in the educational process are indicated. The feasibility of using multimedia in education is illustrated by examples. Of particular importance in education are game forms of learning, in the implementation of which educational elements based on media material play an important role. The influence of the game on the development of attention by means of works of media culture, which are very diverse in form and character, is shown. The importance of the role of multimedia in student education is indicated. In the educational process of multimedia students, a number of educational functions are implemented, which are presented in the article. Recommendations for using multimedia are given.

• 농촌계획
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• 제21권4호
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• pp.187-196
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• 2015

Among the factors of living environment, the one that is the most closely related with our living is the building. It is one of the biggest reasons for energy consumption as it forms 36% of the total energy consumption. Technologies equipped with excellent energy performance can hardly be applied to rural areas that are relatively poorer. Still, 89.8% rural residents are living in detached houses, and backward houses increase their financial burden and result in reduced insulation performance. Accordingly, this study is going to review the latest research written after 2000 dealing with rural houses and their insulation. The purpose of this study is to analyze the factors of insulation and how to improve insulation performance, conduct field research to find out how to apply low energy technologies applicable to houses with the subjects of experimental houses, the passive houses located in Jecheon City, Hongcheon Saldun zero energy houses, and energy independence villages, and find out how to perform follow-up research on insulation for rural houses. According to the findings, the latest research on insulation for rural houses is mostly focused on walls as well as windows and doors. Also, as ways to improve insulation performance, it suggests us to use high performance insulators, introduce new regeneration energy technology, and secure hermeticity. In addition, through field research, this author could find out low energy technologies applicable to houses such as solar energy facilities and heat recovery systems. Advanced research on insulation for rural houses has been focused on how to use materials or new regeneration energy, so follow-up research will have to consider the types of farming area or the residents' mode of living.

• 한국인터넷방송통신학회논문지
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• 제18권5호
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• pp.1-8
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• 2018

최근 사이버 공격은 진보된 기술을 활용하여 방어 기술의 발전 속도보다 빠르게 고도화되고 있어 그 위험수위가 갈수록 높아지고 있다. 이에 대응하기 위해 학계는 물론 산업계에서도 다양한 방법을 적용한 보안 기술을 개발하고 있으며 이를 기반으로 한 보안 시스템들이 적용되고 있다. 본 논문에서는 세대별로 진화하는 공격들을 살펴보고 이에 대응하여 발전하는 네트워크 보안 관련 현황을 소개한다. 특히, 네트워크 보안 시스템 중 최근까지 가장 큰 비중을 차지하고 있는 UTM과 관련하여 상용 제품을 중심으로 해외 및 국내 기술의 동향과 성능 및 기능에 관한 비교 분석을 수행하였다. 또한 차세대 네트워크 기술의 등장으로 인한 네트워크 인프라 변화에 대한 향후 전망에 대해 논의하고자 한다.

• 마이크로전자및패키징학회지
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• 제30권3호
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• pp.11-19
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• 2023

최근 Chat GPT와 같은 인공지능 (Artificial Intelligence, AI) 기술의 급격한 발전에 따라 AI 반도체의 중요성이 강조되고 있다. AI 기술은 빅데이터 처리, 딥 러닝, 알고리즘 등의 요구사항으로 인해 대용량 데이터를 빠르게 처리할 수 있는 능력을 필요로 한다. 그러나 AI 반도체는 대규모 데이터를 처리하는 과정에서 과도한 전력 소비와 데이터 병목현상 문제가 발생한다. 반도체 전공정의 초미세공정이 물리적 한계에 도달함에 따라, AI 반도체의 연산을 위한 최신 패키징 기술이 요구되는 추세이다. 본 고에서는 AI 반도체에 적용가능한 인터포저, TSV, 범핑, Chiplet, 하이브리드 본딩 패키징 기술에 대해서 기술하였다. 이러한 기술들은 AI 반도체의 전력 효율과 연산 속도를 향상시키는데 기여할 것으로 기대된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.248-249
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• 2019

In the nuclear industry, in order to keep pace with the 4th industrial revolution era, they are trying to improve the construction and maintenance ability by utilizing the technologies such as digital twin and VR/AR from the construction stage. However, the nuclear 3D CAD model, which is used as the base in the latest technology, is heavy due to a large number of facilities per unit space compared to other industrial companies, and it is difficult to directly incorporate the latest technology into the results of CAD programs for design purposes. In this study, in order to improve usability, we tried to lighten the 3D model. First, we analyze the existing nuclear power plant 3D model and draw out the problems and features. Secondly, we derived the factors to consider when we make the 3D CAD models lightweight.

• BMB Reports
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• 제40권2호
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• pp.135-141
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• 2007

Conjugation of the methyl group at the fifth carbon of cytosines within the palindromic dinucleotide 5'-CpG-3' sequence (DNA methylation) is the best studied epigenetic mechanism, which acts together with other epigenetic entities: histone modification, chromatin remodeling and microRNAs to shape the chromatin structure of DNA according to its functional state. The cancer genome is frequently characterized by hypermethylation of specific genes concurrently with an overall decrease in the level of 5-methyl cytosine, the pathological implication of which to the cancerous state has been well established. While the latest genome-wide technologies have been applied to classify and interpret the epigenetic layer of gene regulation in the physiological and disease states, the epigenetic testing has also been seriously explored in clinical practice for early detection, refining tumor staging and predicting disease recurrence. This critique reviews the latest research findings on the use of DNA methylation in cancer diagnosis, prognosis and staging/classification.