• 대한조선학회논문집
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• 제33권1호
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• pp.9-18
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• 1996

본 논문은 불균일한 선미 유동장에서 작동하는 프로펠러의 성능 해석을 위한 포텐셜을 기저로 한 판요소법을 기술하고 있다. 본 방법은 법선 다이폴과 쏘오스를 프로펠러의 날개, 허브, 그리고 후류면에 분포하였고, 비정상 유동의 해석 방법으로는 시간 전진법에 의한 방법을 취함으로써 다이폴의 세기를 미지수로 하는 적분방정식을 얻고, 이산화하여 수치적으로 계산하였다. 2차원 날개에 대한 수치해석을 수행하여 해석해와 비교함으로써 시간간격에 대한 수렴성을 확보하였다. 또한, DTRC 4118 프로펠러에 대하여 조화반류하에서 작동하는 프로펠러의 비정상 성능을 해석하여 실험치와 비교함으로써 시간영역에서 프로펠러의 비정상 성능해석이 가능함을 보였다.

• 문화기술의 융합
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• 제6권2호
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• pp.91-98
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• 2020

본 연구는 '트리즈' 이론 중에서도 기술 분야만이 아닌 광범위한 분야에 적용 가능한 'OTSM-TRIZ' 이론을 통하여 창의성 교육이 이루어지도록 하는 모델을 제시하는 에듀테인먼트 창작방법 연구를 목적으로 한다. 이를 위해 본 연구에서는 민담 이야기를 통해 문제가 제시되고 문제 해결에 이르는 과정 속에서 부닥치는 모순을 분석해가며 표준해결에 이르기까지 창의적 사고가 증진되는 모델을 제안하였고, 민담 이야기의 콘텐츠 창작에 있어서는 인지교육에 효과가 높은 애니메이션 기법을 활용하여 스토리텔링 하도록 구상하였다. 이것은 나아가 OTSM-TRIZ의 다양한 활용을 위한 후속담론을 파생시킬 수 있으며 또한 인문학적 상상력과 문화원형을 결합한 새롭고 흥미로운 콘텐츠 창작 방법론을 구축하는데도 일조할 것으로 사료된다.

• 한국전산유체공학회지
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• 제14권4호
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• pp.13-22
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• 2009

A two-phase (gas and liquid) flow analysis solver, named CUPID, has been developed for a realistic simulation of transient two-phase flows in light water nuclear reactor components. In the CUPID solver, a two-fluid three-field model is adopted and the governing equations are solved on unstructured grids for flow analyses in complicated geometries. For the numerical solution scheme, the semi-implicit method of the RELAP5 code, which has been proved to be very stable and accurate for most practical applications of nuclear thermal hydraulics, was used with some modifications for an application to unstructured non-staggered grids. This paper is concerned with the effects of interpolation schemes on the simulation of two-phase flows. In order to stabilize a numerical solution and assure a high numerical accuracy, the second-order upwind scheme is implemented into the CUPID code in the present paper. Some numerical tests have been performed with the implemented scheme and the comparison results between the second-order and first-order upwind schemes are introduced in the present paper. The comparison results among the two interpolation schemes and either the exact solutions or the mesh convergence studies showed the reduced numerical diffusion with the second-order scheme.

• 설비공학논문집
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• 제5권3호
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• pp.187-197
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• 1993

In this study, the numerical analysis and experiments of the hot water storage using the thermal stratification techniques were carried out. The CPU time for a typical run of the the thermal stratification up to 900 seconds took one week for a $81{\times}31$ mesh size and 10 days for a $118{\times}31$ mesh size, respectively, for a cylindrical shape of the storage. In the initial stage, the numerical results were in favorable agreement with the experimental results, but it showed that the temperature gradients in the storage decreased gradually with time. It was also found that the increase of ${\delta}t$ decreased the convergent speed due to the intensive fluctuation of the velocity field in every iteration. The increase of numbers of grids is projected to forecast a more accurate result, but it made the computing time longer and woul slow down convergence. At the experiments of the flow visualization, it was confirmed that the thermal stratification was apparently built up due to the installation of diffuser at the lower part of the storage. Thus, the thermal performance of the storage could be improved by installing the diffusers at the inlet and outlet.

• Applied Science and Convergence Technology
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• 제23권3호
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• pp.134-138
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• 2014

One-dimensional nanostructures such as nanowires have been extensively investigated as a promising type of material for applications of nanoscale technology. The fabrication of single-nanowire devices are consequently important and interesting. This study introduced a feasible method for growing CuO nanowires on Cu foils. The nanowires had diameters of 10~150 nm and lengths of more than $7{\mu}m$ and were grown by means of thermal oxidation in a vacuum. They were entirely and uniformly grown over the Cu foil surfaces and could be extracted and dispersed in an ethanol solution for further purposes. In addition, a simple fabrication method for realizing device functionality from a single CuO nanowire was reported. Fabricated devices were carefully checked by field-emission scanning electron microscopy (SEM). The probability of the realization of a single-CuO-nanowire device relative to that of all other types was estimated to be around 25%. Finally, the I-V characteristics of the devices were analyzed.

• 패션비즈니스
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• 제14권6호
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• pp.70-83
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• 2010

With the rapid development of science and technology and the increased preference by consumers for high-function products, many products are being developed through the fusion of technologies in different industries. Among such fusion technologies, digital clothing which combines clothing with computer functions is being examined as a new growth item. The objectives of this study are to examine the concept, history, development, and market of intelligent clothing, in order to discuss future directions for the development of digital clothing technology. intelligent clothing (wearable computers) originated in the 1960s from the concept of separating computing equipment and attaching it to the body. This technology was studied intensively from the early 1980s and to the early 1990s. In the late 1990s, studies on wearable computers began to develop intelligent/digital clothing that was more comfortable and beneficial to users. Depending on the user and purpose, intelligent/digital clothing is now being developed and used in diverse industrial areas that include sports, medicine, military, entertainment, daily life, and business. Many experts forecast a huge growth potential for the digital textile/clothing market, and predict the fastest market growth in the field of healthcare/medicine. There exists a need to find solutions for many related technological, economic, and social issues for the steady dissemination and advancement of intelligent/digital clothing in various industries. Further, research should be continued on effective fusion technologies that reflect human sensitivity and that increase user convenience and benefits.

• 창의정보문화연구
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• 제7권1호
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• pp.11-19
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• 2021

인공지능 국가전략이 발표되면서 인공지능의 교육에 대한 다양한 정책들이 제안되고 있고 교사를 대상으로 하는 인공지능융합교육도 활발히 추진되고 있다. 또한 인공지능 스피커는 각 가정에 판매 및 보급이 되고 있는 실정이고, 인공지능 스피커의 교육적 활용 현장연구들이 시작되고 있다. 이 연구에서는 인공지능 윤리에서 인공지능 스피커가 발생시킬 논란이 될 문제들을 살펴보고, 가정이나 학교에서 인공지능 스피커가 활용될 때 발생할 수 있는 윤리적 딜레마를 도출해보고자 한다. 이 딜레마는 인공지능 스피커에 대한 집단별 도덕적 판단력 수준 측정 MCT(Moral Competence Test)에 활용할 수 있을 것이다.

• 전자통신동향분석
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• 제37권5호
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• pp.11-21
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• 2022

GaN (Gallium-Nitride) is a promising candidate material in various radio frequency applications due to its inherent properties including wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. Notably, AlGaN/GaN heterostructure field effect transistor exhibits high operating voltage and high power-density/power at high frequency. In next-generation radar systems, GaN power transistors and monolithic microwave integrated circuits (MMICs) are significant components of transmitting and receiving modules. In this paper, we introduce technological trends for C-/X-/Ku-band GaN MMICs including power amplifiers, low noise amplifiers and switch MMICs, focusing on the status of GaN MMIC fabrication technology and GaN foundry service. Additionally, we review the research for the localization of C-/X-/Ku-band GaN MMICs using in-house GaN transistor and MMIC fabrication technology. We also discuss the results of C-/X-/Ku-band GaN MMICs developed at Defense Materials and Components Convergence Research Department in ETRI.

• Geomechanics and Engineering
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• 제31권4호
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• pp.353-364
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• 2022

This study presents a hybrid algorithm for classifying the rock joints, where the improved artificial bee colony (IABC) and the fuzzy C-means (FCM) clustering algorithms are incorporated to take advantage of the artificial bee colony (ABC) algorithm by tuning the FCM clustering algorithm to obtain the more reasonable and stable result. A coefficient is proposed to reduce the amount of blind random searches and speed up convergence, thus achieving the goals of optimizing and improving the ABC algorithm. The results from the IABC algorithm are used as initial parameters in FCM to avoid falling to the local optimum in the local search, thus obtaining stable classifying results. Two validity indices are adopted to verify the rationality and practicability of the IABC-FCM algorithm in classifying the rock joints, and the optimal amount of joint sets is obtained based on the two validity indices. Two illustrative examples, i.e., the simulated rock joints data and the field-survey rock joints data, are used in the verification to check the feasibility and practicability in rock engineering for the proposed algorithm. The results show that the IABC-FCM algorithm could be applicable in classifying the rock joint sets.

• International journal of advanced smart convergence
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• 제13권2호
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• pp.205-213
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• 2024

This study uses a large language model (LLM) to identify Aristotle's rhetorical principles (ethos, pathos, and logos) in COVID-19 information on Naver Knowledge-iN, South Korea's leading question-and-answer community. The research analyzed the differences of these rhetorical elements in the most upvoted answers with random answers. A total of 193 answer pairs were randomly selected, with 135 pairs for training and 58 for testing. These answers were then coded in line with the rhetorical principles to refine GPT 3.5-based models. The models achieved F1 scores of .88 (ethos), .81 (pathos), and .69 (logos). Subsequent analysis of 128 new answer pairs revealed that logos, particularly factual information and logical reasoning, was more frequently used in the most upvoted answers than the random answers, whereas there were no differences in ethos and pathos between the answer groups. The results suggest that health information consumers value information including logos while ethos and pathos were not associated with consumers' preference for health information. By utilizing an LLM for the analysis of persuasive content, which has been typically conducted manually with much labor and time, this study not only demonstrates the feasibility of using an LLM for latent content but also contributes to expanding the horizon in the field of AI text extraction.