• 대한기계학회논문집
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• 제18권4호
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• pp.1057-1063
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• 1994

An instantaneous frequency analysis is a technique to examine a signature for the rotating machinery if the signal has several transitions within a cycle. This paper discusses the conditions of existing negative frequency components in the instantaneous frequency. By using a signal consisted of two frequency components, the instantaneous frequency analysis is conducted while the amplitude ratio between two frequency components has been changed. The analysis shows that, depending on the amplitude ratio, the instantaneous frequencies have averaged, zero-valued, or negative components. It turns out that the negative-valued instantaneous frequencies, which have been regarded as the noise effect, are the consequence of the calculation process for the multisignal components. The criteria of existing the negative values in instantaneous frequencies is given in terms of the relative amplitude ratio and the frequency difference. Especially when the amplitude ratio approaches to 1, the instantaneous frequency fluctuates ${\pm}\infty$ in theory, which implies that instantaneous frequency has unstable region around the amplitude ratio, 1.Also, as the frequency difference between major signal components is increased, the region of existing negative instantaneous becomes broader. In an instantaneous frequency analysis, therefore, a narrow band analysis is suggested, with extreme care if the amplitude ratio approaches to 1. In this paper, a vibration signal monitored from a rotating machinery is also examined as an application example in order to show the existence of negative instantaneous frequencies components.

• 정보처리학회논문지D
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• 제13D권7호
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• pp.947-958
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• 2006

컴포넌트 확장성 및 재사용성을 향상시키기 위해서는 분석단계에서부터 가변적인 것들을 규칙기반으로 분석해서 컴포넌트로 식별할 필요가 있다. 본 논문에서는 시스템 외부 이벤트에 대해 트랜잭션 처리를 규칙기반으로 처리해야 하는 도메인 상에서 객체 기반의 중요 개념을 규칙기반으로 효과적으로 추출해 UML Components 개발 프로세스 상에서 가변적인 컴포넌트를 개발할 수 있는 규칙 기반 분석 패턴을 제시한다. 업무 지식이나 경험이 다른 많은 분석가들이 서브 시스템 많은 규칙 기반의 가변적인 복잡한 비즈니스 업무 분석 시 제안한 분석 패턴을 사용할 경우 분석 산출물의 일관성이나 가독성을 좋게 하며 또한 UML Components 방법론상에서 효과적으로 가변적인 비즈니스 컴포넌트들을 식별할 수 있다. 이러한 분석 패턴의 타당성을 증명하기 위해 본 논문에서는 가변적인 규칙기반으로 업무를 처리하는 은행 수신과 수출입 업무 도메인에 적용한 결과 패턴에서 제시한 중요 개념을 기반으로 거의 유사한 비즈니스 개념 모델을 도출할 수 있었으며 또한 이들 중요 개념을 기반으로 UML Components 개발 프로세스 상에서 가변적인 비즈니스 컴포넌트를 효과적으로 식별할 수 있었다.

• East Asian mathematical journal
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• 제34권4호
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• pp.451-462
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• 2018

This study analyzed the learning components of the web-based adaptive math learning programs in order to develop adaptive math learning program using artificial intelligence. The components of the web-based adaptive math learning program set for analysis are classified into learning process presentation, concept learning, problem presentation, problem solving process, and learning result processing then analyzed three programs. As a result of analysis, the typical characteristic of components is that it uses a method of repeatedly presenting the same type of problem in order to learn one concept.

• 한국지진공학회논문집
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• 제25권6호
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• pp.267-274
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• 2021

Seismic fragility analysis of a structure is generally performed for the expected critical component of a structure. The seismic fragility analysis assumes that all the components behave independently in a structural system. A bridge system consists of many inter-connected components. Thus, for an accurate evaluation of the seismic fragility of a bridge, the seismic fragility analysis requires the composition of probabilities considering the correlation between structural components. This study presented a procedure to obtain the seismic fragility curve of a bridge system, considering the correlation between bridge components. Seismic fragility analysis was performed on a PSC bridge that is considered as the central infrastructure. The analysis results showed that the probability of the seismic fragility curve of the bridge system was higher than that of each bridge component.

• KIEAE Journal
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• 제9권3호
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• pp.37-46
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• 2009

This study conducted an evaluation of the streetscape improvement project of the Gwangbok Street through analysis of visual and perceptual characteristics by comparing selected pictures of streetscape before and after the project. This work has conducted an analysis of the environmental factors which influence subjects' satisfaction degrees including physical street equipments and street view factors which are main contents of this project. Using a satisfaction analysis and factor analysis, each factor's significance was verified quantitatively. As a result of the analysis, physical components of the streetscape were classified into 4 types according to project's effectiveness and improvement priorities. These 4 types include (1) Components for maintenance because of higher satisfaction and higher importance, (2) Components for improvement because of lower satisfaction and higher importance, (3) Components for good business fruits because of higher satisfaction and lower importance, and (4) Components for unnecessity because of lower satisfaction and lower importance.

• 한국연초학회지
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• 제25권2호
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• pp.144-153
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• 2003

This study was carried out to determine the relationship between smoke components and sensory evaluation by changes tobacco leaf blending. Seven different cigarettes were made by adding different types of oriental, reconstituted and expanded tobacco leaves. 62 kinds of smoke components which were 6 of general components, 34 of semi-volatile and volatile components, 9 of acid components, and 13 of phenolic components were analyzed. Eight kinds of sensory item were evaluated and also electronic nose system data was collected. All smoke components and sensory characteristics of mainstream smoke were changed by the different blending. To determine the relationship between smoke components and sensory test, the correlation and regression analysis were carried out by using SPSS statistical program. Tar, pH, and CO showed a high correlation with sensory evaluation item. As tar related to hotness, CO have a high correlation with offensive aroma. Semi-volatile and volatile components of smoke related to sensory characteristics such as aroma, taste, irritation, hotness and smoothness. When propylene, l,3-butadiene, butane, isoprene, and 2-methylfuran showed a high correlation with aroma; methyl chloride, methanol, toluene, ethyl benzene showed a high correlation with irritation. Some acidic components and phenolic components of smoke also had a high relation to smoke volume. Especially the acidic components such as 2-furoic acid, 2-hydroxybutyric acid, phenylacetic acid and palmitic acid; the phenolic components such as 4-vinyl phenol, pyrocatechol, 3-methyl catechol, hydroquinone showed a high correlation with smoke volume. As using regression analysis, it was possible to estimate the results of sensory evaluation from the smoke analysis data. From the results of electronic nose system analysis, we can find the different pattern by adding expanded tobacco leaf.

• 한국치위생학회지
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• 제15권5호
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• pp.873-880
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• 2015

Objectives: The aim of the study was to investigate the attitude and influencing factors toward basic life support in the dental hygienists. Methods: A self-reported questionnaire was completed by 218 dental hygienists in Gwangju. The questionnaire consisted of the general characteristics of the subjects and attitude toward basic life support (BLS). The attitude included cognitive belief, behavioral components, and emotional components. The data were analyzed by independent t-test, one-way ANOVA and multiple regression analysis by using IBM SPSS 21.0 program. Results: The cognitive belief, behavioral component, and emotional components of attitude toward BLS had higher scores in those who were between 34-34 years old and had more than 10 years of career. Most of them worked in dental clinic and did not earn the BLS certificate. There were positive correlations between the cognitive belief, behavioral components, and emotional components toward BLS. By the regression analysis, cognitive belief toward BLS was positively associated with educational experience within a year, behavioral components, and emotional components. The behavioral components were associated with working between 5-10 years in dental clinic and the emotional components. Conclusions: The attitude toward BLS in the dental hygienists was low in cognitive belief, behavioral components, and emotional components. Therefore, BLS education must be expanded to the dental hygienists.

• 한국식품영양학회지
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• 제13권1호
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• pp.66-70
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• 2000

The volatile components of Korea ginger were compared by using different isolation methods, head-space sampling procedure(HSSP), simultaneous distillation extrction(SDE) and soild pahse micro-extractions(SPME). Sixty-one components were identified by GC-MSD in the extracts obtained from each extraction methods. However, the components identified showed a difference in their composition wit the extraction methods. In the extract by HSSP, fifty-five components including a high volatile compound such as acetaldehyde, ethylacetate, 2,3-butandione were detected, and thirty-one components were identified in the extract by SPME. While, the low volatile components such as elemol, zingiberenol and ${\beta}$-eudesmol were detected only in the extract by SDE method. The results suggest that SDE method is the best for the analysis of low volatile components, whereas HSSP is a proper method for the analysis of high volatile components from natural resources.

• 대한안전경영과학회지
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• 제3권2호
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• pp.113-121
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• 2001

Today, facilities are composed of many complex components or parts. Because of this characteristics, the frequency of failures is decreasing, but the strength of failures is increasing; therefore, the failure analysis about many complex components or parts was needed. In the former research about Fault Tree Analysis, failure data of similar facilities have been used for forecasting about target system or components, but in case that the system or components for forecasting failure is new or qualitative and quantitative data are given simultaneously, there are many difficulty in using Fault Tree Analysis with this incorrect failure data. Therefore, this paper deal with the Fault Tree Analysis method which be applied with Fuzzy theory in above case. In case that , therefore, if there is no the correct failure data, it is represented a system or components as qualitative variable. subsequently, it converted to the quantitative value using fuzzy theory, and the values used as the value for failure forecast.

• Nuclear Engineering and Technology
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• 제34권4호
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• pp.331-343
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• 2002

We performed an importance analysis of In-Service Testing (157) components for Ulchin Unit 3 using the integrated evaluation method for categorizing component safety significance developed in this study. The developed method is basically aimed at having a PSA expert perform an importance analysis using PSA and its related information. The importance analysis using the developed method is initiated by ranking the component importance using quantitative PSA information. The importance analysis of the IST components not modeled in the PSA is performed through the engineering judgment, based on the expertise of PSA, and the quantitative and qualitative information for the 157 components. The PSA scope for importance analysis includes not only Level 1 and 2 internal PSA but also Level 1 external and shutdown/low power operation PSA. The importance analysis results of valves show that 167 (26.55%) of the 629 IST valves are HSSCs and 462 (73.45%) are LSSCs. Those of pumps also show that 28 (70%)of the 40157 pumps are HSSCs and 12 (30%) are LSSCs.