• 한국분말재료학회지
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• 제23권2호
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• pp.126-131
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• 2016

The recent rise in applications of thermoelectric materials has attracted interest in studies toward the fabrication of thermoelectric materials using mass production techniques. In this study, we successfully fabricate n-type $Bi_2Te_{2.7}Se_{0.3}$ material by a combination of mass production powder metallurgy techniques, gas atomization, and spark plasma sintering. In addition, to examine the effects of hydrogen reduction in the microstructure, the thermoelectric and mechanical properties are measured and analyzed. Here, almost 60% of the oxygen content of the powder are eliminated after hydrogen reduction for 4 h at $360^{\circ}C$. Micrographs of the powder show that the reduced powder had a comparatively clean surface and larger grain sizes than unreduced powder. The density of the consolidated bulk using as-atomized powder and reduced atomized powder exceeds 99%. The thermoelectric power factor of the sample prepared by reduction of powder is 20% better than that of the sample prepared using unreduced powder.

• 대한전자공학회논문지TC
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• 제48권5호
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• pp.8-15
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• 2011

LTE-Advanced 시스템은 하향링크에서 1Gbps 상향링크에서 500Mbps 데이터 송신율을 목표로 한다. 이는 100MHz 이상의 스펙트럼 할당과 상향링크에서의 진보한 MIMO 안테나 기법에 의해 이루어진다. 본 논문은 LTE-A에서 정의하는 SC-FDMA 시스템 모델에서 LTE 하향링크의 코드북, SVD 코드북, EGT 코드북을 포함하는 상향링크 선부호화 기법을 분석한다. 마지막으로 SC-FDMA 기법에서도 발생하는 PAPR을 컴퓨터 시뮬레이션으로 분석하여, 비선형 전력 증폭기를 송신부에 고려한 채널 모델에서 동 이득 전송 기법이 다른 선 부호화 기법보다 우수함을 증명한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.781-786
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• 1991

This paper introduces a new methodology for multisensor data fusion. The method makes use of fuzzy techniques and possibility distribution as a fuzzy restriction which acts as an elastic constraint on the values that may be assigned to a variable. We propose a simple sensor fuzzy modeling method which can be used for cluster validity analysis. As a result, the feasibility of these multisensor data fusion modules is demonstrated by computer simulation applicable to the problem of object identification.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.655-657
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• 2002

The carbon nanotube emitters for field emission displays were fabricated by screen printing techniques. The pastes for screen printing are composed of organic binders, carbon nanotubes, and some additive materials. Then the pastes were printed on Cr-coated/Ag-printed soda-lime glass substrates. From the I-V characteristics, the turn-on field of SWNT was lower than that of MWNT. The decrease in the mesh size of screen masks resulted in decreasing the turn-on field and increasing the electron emission current. When the carbon nanotubes were mixed with glass frit, glass frit appeared to contribute to the vertically aligning of carbon nanotubes on glass.

• Nuclear Engineering and Technology
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• 제36권4호
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• pp.295-303
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• 2004

Software inspection is widely believed to be an effective method for software verification and validation (V&V). However, software inspection is labor-intensive and, since it uses little technology, software inspection is viewed upon as unsuitable for a more technology-oriented development environment. Nevertheless, software inspection is gaining in popularity. KAIST Nuclear I&C and Information Engineering Laboratory (NICIEL) has developed software management and inspection support tools, collectively named "SIS-RT. "SIS-RT is designed to partially automate the software inspection processes. SIS-RT supports the analyses of traceability between a given set of specification documents. To make SIS-RT compatible for documents written in Korean, certain techniques in natural language processing have been studied [9]. Among the techniques considered, case grammar is most suitable for analyses of the Korean language [3]. In this paper, we propose a methodology that uses a case grammar approach to analyze the traceability between documents written in Korean. A discussion regarding some examples of such an analysis will follow.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1012-1015
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• 2005

We have developed the technique of fabricating triode structure with simple stacking method using a polymer insulator that is suitable for large panel and the activation method after the fabrication. By the techniques, a test panel was manufactured and proves good emission property and uniformity.

• 한국가구학회지
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• 제20권5호
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• pp.431-439
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• 2009

When we look at the pattern techniques of wooden furniture in the 19th century Joeson Dynasty, we see that furniture patterns in the main living room were showy and colorful while furniture patterns in the library room, where noble men used to study, were natural and moderate, retaining the actual color of the material without any artificial coloring. Even the serial patterns in the Hwe-Jang technique, Which were used rarely, used moderate techniques. such as weaving in patterns with colorless woods - willow and black persimmon ets. - rather than using excessive techniques. However, considering the marquetry&intarsia technique of ceramic and the silver string intarsia technique of metal then current, wood work must also have been technically advanced. Korean modern wood furniture needs remedies to improve the standard of sound wood work techniques. This study shows that pattern unit production, composition techniques, and color effects etc. Using colored patterns bars, by improving the pattern composition techniques of Marquetry&Intarsia, can be substituted for the production logic of modern manufactured furniture.

• 항공우주시스템공학회지
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• 제10권3호
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• pp.63-69
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• 2016

The properties of composite materials, when compared to those of metallic materials, are highly variable due to many factors including the batch-to-batch variability of raw materials, the prepreg manufacturing process, material handling, part-fabrication techniques, ply-stacking sequences, environmental conditions, and test procedures. It is therefore necessary to apply reliable statistical-analysis techniques to obtain the design allowables of composite materials. A new composite-material qualification process has been developed by the Advanced General Aviation Transport Experiments (AGATE) consortium to yield the lamina-design allowables of composite materials according to standardized coupon-level tests and statistical techniques; moreover, the generated allowables database can be shared among multiple users without a repeating of the full qualification procedure by each user. In 2005, NASA established the National Center for Advanced Materials Performance (NCAMP) with the purpose of refining and enhancing the AGATE process to a self-sustaining level to serve the entire aerospace industry. In this paper, the statistical techniques and procedures for the generation of the allowables of aerospace composite materials will be discussed with a focus on the pooling-across-environments method.

• International journal of advanced smart convergence
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• 제13권2호
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• pp.48-60
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• 2024

With the exponential growth of satellite data utilization, machine learning has become pivotal in enhancing innovation and cybersecurity in satellite systems. This paper investigates the role of machine learning techniques in identifying and mitigating vulnerabilities and code smells within satellite software. We explore satellite system architecture and survey applications like vulnerability analysis, source code refactoring, and security flaw detection, emphasizing feature extraction methodologies such as Abstract Syntax Trees (AST) and Control Flow Graphs (CFG). We present practical examples of feature extraction and training models using machine learning techniques like Random Forests, Support Vector Machines, and Gradient Boosting. Additionally, we review open-access satellite datasets and address prevalent code smells through systematic refactoring solutions. By integrating continuous code review and refactoring into satellite software development, this research aims to improve maintainability, scalability, and cybersecurity, providing novel insights for the advancement of satellite software development and security. The value of this paper lies in its focus on addressing the identification of vulnerabilities and resolution of code smells in satellite software. In terms of the authors' contributions, we detail methods for applying machine learning to identify potential vulnerabilities and code smells in satellite software. Furthermore, the study presents techniques for feature extraction and model training, utilizing Abstract Syntax Trees (AST) and Control Flow Graphs (CFG) to extract relevant features for machine learning training. Regarding the results, we discuss the analysis of vulnerabilities, the identification of code smells, maintenance, and security enhancement through practical examples. This underscores the significant improvement in the maintainability and scalability of satellite software through continuous code review and refactoring.

• Journal of Advanced Marine Engineering and Technology
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• 제16권5호
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• pp.77-84
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• 1992

In the most of acoustic system with low flow rate and low pressure level, one-dimensional, linear modeling techniques are used very well. At low frequency, the tube is modeled as inertia element and cavity as capacitance element, and to extend the range of frequency normal mode oscillators are represented. Bond graph modelling techniques are proposed to predict TL (Transmission Loss) and time response which is impossible by transfer matrix in muffler system. A simple acoustic filter which consists of several tubes and cawities is analyzed in both time and frequency domain.