• 대한기계학회논문집B
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• 제34권6호
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• pp.569-577
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• 2010

다상 유체 시스템에 적용할 수 있는 다중스케일 입자 시뮬레이션 기법을 개발하였다. 거시 모델과 미시모델이 만나는 경계영역에서 세가지로 구별되는 기능을 수행하도록 하였다. 먼저, 기상과 액상을 분리하여 연결하기 위해 벽을 설정하였다. 또 경계영역을 근처에서 경계의 위치를 측정하고 이것에 벽의 각도와 위치가 연동하여 접촉각 값을 미시모델에서 거시모델로 전달하게 하였다. 마지막으로, 입자의 삽입과 제거를 통해 경계영역의 질량과 온도를 거시적 조건에 맞추도록 하였다. 이 알고리즘들을 적용한 완전습윤과 부분습윤시스템들은 좋은 결합 결과를 보였다.

• 환경영향평가
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• 제2권2호
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• pp.111-116
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• 1993

The EIA system was developed during ten odd years of introduction. On the other hand, the contentional development representing systematical fidelity does not match to it. I surveyed the problems of EIA on the point of environmental items with no legal standards. EIA is being executed only once on the planning stage. If the present EIA system has two times of execution, the quality of EIA will be much better. First, on the stage of deciding location of the project, EIA should be done. And next, detailed EIA should be done on the stage of executing the project. To describe the problems of EIA, I surveyed the legislations on the point of the former stages, investigation of present status and anticipation. And I tried a theoretical approach to EIA. The knowledge of things, the subject's standpoint and his valuation are all put together in the EIA. The knowledge of relationship between air and water pollutants and their impact on human is accumulated much. On the other hand, the knowledge of the compounded item, fauna-flora(natural ecology) is partial and causes many difficulties. I pointed out the absurdities of assessment technique dealing the standards and introduced assessment technique being applied to items with no physico-chemical standards such as wild lives.

• 한국정보과학회논문지:데이타베이스
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• 제28권2호
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• pp.253-265
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• 2001

본 논문은 이동 컴퓨팅 환경에서 연속 부분 질의의 효과적인 처리를 위한 캐시 관리 방안을 제안한다. 연속 부분 부합 질의란 질의의 결과가 클라이언트의 메모리에 일관성을 유지하면서 지속되는 부분 부합 질의이다. 기존의 이동 환경을 위한 캐시 관리 기법은 레코드 식별자를 기반으로 하는 방법들이다. 하지만, 부분 부합 질의는 데이터의 내용을 기반으로 탐색하는 질의이기 때문에 이러한 레코드 식별자를 기반으로 하는 방법들은 캐시 관리를 효율적으로 할 수 없다. 제안하는 캐시 관리 방안에서는, 이동 클라이언트의 캐시 상태를 프레디킷(predicate)으로 기술하고, 서버가 캐시 관리를 위해 클라이언트에게 방송하는 캐시 무효화 정보, 즉 Cache Invalidation Reports(CIR)을 프레디킷으로 구성한다. 이러한 프레디킷 표현을 사용하여, 일련의 캐시 관리 기법-억지 방법(the brute-force method), 빼기 방법(the subtraction method), 교차 방법(the intersection method)-들을 제안한다. 그리고, 제안하는 방법의 계산 복잡도를 계산한다.

• 제어로봇시스템학회논문지
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• 제3권5호
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• pp.520-525
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• 1997

This paper presents a fault detection and diagnosis methodology based on weighted symptom model and pattern matching between the coming fault propagation trend and the simulated one. In the first step, backward chaining is used to find the possible cause candidates for the faults. The weighted symptom model is used to generate those candidates. The weight is determined from dynamic simulation. Using WSM, the methodology can generate the cause candidates and rank them according to the probability. Second, the fault propagation trends identified from the partial or complete sequence of measurements are compared with the standard fault propagation trends stored a priori. A pattern matching algorithm based on a number of triangular episodes is used to effectively match those trends. The standard trends have been generated using dynamic simulation and stored a priori. The proposed methodology has been illustrated using two case studies, and the results showed satisfactory diagnostic resolution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3589-3605
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• 2018

In this paper, we investigate an individual channel estimation problem for multiple-input multiple-output (MIMO) two-way amplify-and-forward (AF) relay networks. To avoid self-interference during the estimation of the individual MIMO channels, a novel blind interference cancellation (BIC) approach is proposed based on an orthogonal preceding framework, where a pair of orthogonal precoding matrices is utilized at the source nodes. By designing an optimal decoding scheme, we propose to decompose the bidirectional transmission into a pair of unidirectional transmissions. Unlike most existing approaches, we make the practical assumption that the nonreciprocal MIMO channel and the mutual interference of multiple antennas are both taken into consideration. Under the precoding framework, we employ an orthogonal superimposed training strategy to obtain the individual MIMO channels. However, the AF strategy causes the noise at the terminal to be the sum of the local noise and the relay-propagated noise. To remove the relay-propagated noise during the estimation of the second-hop channel, a partial noise-nulling method is designed. We also derive a closed-form expression for the total mean square error (MSE) of the MIMO channel from which we compute the optimal power allocation. The simulation results demonstrate that the analytical and simulated curves match fully.

• 한국세라믹학회지
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• 제52권5호
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• pp.344-349
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• 2015

An interconnect is the key component of solid oxide fuel cells that electrically connects unit cells and separates fuel from oxidant in the adjoining cells. To improve their surface stability in high-temperature oxidizing environments, metallic interconnects are usually coated with conductive oxides. In this study, lanthanum nickelates ($LaNiO_3$) with a perovskite structure are synthesized and applied as protective coatings on a metallic interconnect (Crofer 22 APU). The partial substitution of Co, Cu, and Fe for Ni improves electrical conductivity as well as thermal expansion match with the Crofer interconnect. The protective perovskite layers are fabricated on the interconnects by a slurry coating process combined with optimized heat-treatment. The perovskite-coated interconnects show area-specific resistances as low as $16.5-37.5m{\Omega}{\cdot}cm^2$ at $800^{\circ}C$.

• 한국문헌정보학회지
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• 제21권
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• pp.249-290
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• 1991

Theoretical developments in the information retrieval have offered a number of alternatives to traditional Boolean retrieval. Probability theory and fuzzy set theory have played prominent roles here. Fuzzy set theory is an attempt to generalize traditional set theory by permitting partial membership in a set and this means recognizing different degrees to which a document can match a request. In this study, an experimentation of a document retrieval system using the fuzzy relation matrix of the keywords is described and the results are offered. The queries composed of keywords and Boolean operaters AND, OR, NOT were processed in the retrieval method, and the method was implemented on the PC of 32bit level (30 MHz) in an experimental system. The measurement of the recall ratio and precision ratio verified the effectiveness of the proposed fuzzy relation matrix of keywords and retrieval method. Compared to traditional crisp method in the same document database, the recall ratio increased $10\%$ high although the precision ratio decreased slightly. The problems, in this experiment, to be resolved are first, the design of the automatic data input and fuzzy indexing modules, through which the system . can have the ability of competition and usefulness. Second, devising a systematic procedure for assigning fuzzy weights to keywords in documents and in queries.

• 말소리와 음성과학
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• 제12권4호
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• pp.19-25
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• 2020

This study examined thirty-one Korean students' pronunciation of an English passage using a speech recognition application, Speechnotes, and two Canadian raters' evaluations of their speech according to the International English Language Testing System (IELTS) band criteria to assess the possibility of using the application as a teaching aid for pronunciation education. The results showed that the grand average percentage of correctly recognized words was 77.7%. From the moderate recognition rate, the pronunciation level of the participants was construed as intermediate and higher. The recognition rate varied depending on the composition of the content words and the function words in each given sentence. Frequency counts of unrecognized words by group level and word type revealed the typical pronunciation problems of the participants, including fricatives and nasals. The IELTS bands chosen by the two native raters for the rainbow passage had a moderately high correlation with each other. A moderate correlation was reported between the number of correctly recognized content words and the raters' bands, while an almost a negligible correlation was found between the function words and the raters' bands. From these results, the author concludes that the speech recognition application could constitute a partial aid for diagnosing each individual's or the group's pronunciation problems, but further studies are still needed to match human raters.

• 문화기술의 융합
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• 제7권3호
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• pp.599-604
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• 2021

AI 인공지능으로 각 분야가 융합된 시대에 디자인에서는 AI-CARE 기능의 디자인과 UI UX 디자인이 각광 받는 시기에 들어와 있다. 새로운 기능에 맞는 시각 효과는 형태 디자인의 적용과 색의 트랜드가 중요하다. 본 논문에서는 이를 활용하여 형태 트랜드의 정리와 적용에 관한 사례를 제시하고, 디자인 방향을 제시하고자 한다. 도입부에서는 최신 디자인 환경 요인을 분석하여 새로운 제안의 방향으로 연구하였다. 본문에서는 기능 디자인 형태를 분리하여 기획에서의 디자인 방향과 고려사항 대한 부분을 연구하였으며, 디자인 작업의 방향성을 제시하였다. 형태와 색채 부분의 단계에서 미니멀리즘과 유니버셜 디자인, 어포던스 디자인의 흐름에 맞는 계획서를 제안하였다. 사례 실습을 바탕으로 한 본론의 연구 방법은 부분별 디자인 작업에 특화된 형태와 색채에 관한 콘텐츠를 어떻게 고려할 것인가에 대한 고찰이며, 콘텐츠 이미지에서 새로운 영역의 UI UX 분야 그래픽 제작이 실현 가능하도록 제안하였다. 본 연구를 통해 AI CARE 베드 PART별로, 디자인 방향성과 타당성을 제안함으로써 형태와 색의 도출 방법의 디자인 방향성과 기획에 도달했다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.4111-4111
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• 2001

When a drug is prepared in a tablet, the active component represents only a small portion of the dosage form. The other components of the formulation include materials to assist in the dissolution, antioxidants, coloring agents and bulk fillers. The tablets are tested using approved testing methods usually involving separation and subsequent quantification of the active component. Tablets may also be tested by near-Infrared Reflectance spectrometry (NIRS). In the present study, based on NIRS and multivariate calibration methods, a novel and precise method is developed for direct determination of ascorbic acid in vitamin C tablet. Two different tablet formulations were powdered in three different sizes, 63-125 ${\mu}{\textrm}{m}$, and examined. Spectral region of 4750-4950 $cm^{-1}$ / was used and optimized for quantitative operations. Partial least squares (PLS) and multiple linear regression (MLR) methods were performed for this spectral region. The results of optimized PLS and MLR methods showed that reproducibility increase with decreasing grain size and standard error of calibration (SEP) of less than 1% w/w of ascorbic acid and a correlation coefficient of 0.998 can be achieved. The PLS method showed better results than MLR. Seven overdose and underdose samples (prepared in the laboratory to match marketed products) were tested by proposed and iodometric standard methods. A correlation between NIRS predicted ascorbic acid values and iodomet.ic values was calculated ($R^2$=0.9950). Finally, the direct analysis of individual intact tablets in their unit-dose packages (Blistering in aluminum and PVC foils) obtained from market were also carried out and a correlation coefficient of 0.9989 and SEP of 0.931% w/w of ascorbic acid were achieved.