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        검색결과 219

        81.
        2013.04 구독 인증기관·개인회원 무료
        Benthic macroinvertebrates were collected using the Surber sampler from streams in forest areas in Southern Korea in spring and summer. Self-Organizing Map (SOM) was utilized to reveal community patterns in response to natural and anthropogenic variability in different seasons. The gradient was mainly observed according to degree of pollution and altitude. Subsequently, community compositions reflected seasonality in less-polluted area, showing difference in functional feeding groups. Gatherer-collectors and filterer-collectors were abundantly collected in spring whereas scrapers and predators were sampled in a majority in late summer. Representative species groups were identified in different seasons. persistence in communities in response to natural and anthropogenic variability.
        82.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대기 및 해양의 대규모 환경에서 열대저기압 발생의 잠재적 빈도는 잠재생성지수(GPI; Genesis Potential Index)를 이용하여 예측할 수 있다. 본 연구에서는 18개의 CMIP5 기후모델을 이용하여 GPI의 연진동 및 경년변동성이 분석되었다. 비교를 위하여 재분석자료로부터 계산된 GPI의 연진동이 재조명되었다. 특히 CMIP5 기후모델과 재분석자료에 의한 GPI가 비교되었고, 그 차이에 대한 가능한 해석이 논의되었다. ENSO (El Nino and Southern Oscillation)는 열대 저기압 발생 및 경로에 영향을 주는 열대 기후현상이다. 잠재생성지수가 네 개의 대규모 매개변수의 함수임을 이용함으로써 열대저기압발생에 대한 역학적 해석이 제시되었다. 본 연구에서는 엘니뇨 혹은 라니냐 해에 GPI 편차를 논의하였고, 그 편차에 가장 영향을 많이 주는 인자를 찾았다. 또한 여러 대규모 인자를 활용하여 북태평양지역 열대저기압 발생에 대하여 가능한 기작을 논의하였다.
        4,500원
        83.
        2012.10 구독 인증기관 무료, 개인회원 유료
        When it comes to designing a product or a process, the robust parameter design (RPD) methodology devised by Taguchi is recognized as a way to produce products or processes with less variability, while the specifications of products or processes are met, so that the ratio of nonconforming products can be as minimized as possible. Nevertheless, as a matter of fact, there have been many pros and cons concerning the RPD method, mainly because of the use of signal to noise ratio as the measure of quality characteristic. Meanwhile, the variability analysis method has been highly recommended as an alternative of the RPD in the literature. In this paper, it is demonstrated that RPD can also be implemented within the framework of the variability analysis, which is sounder in the statistical sense. In light of an example of RPD approach, the modeling and estimation procedure is discussed in some detail with a view to a comparison of the two methods.
        4,200원
        84.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문의 목적은 불안과 우울 상태를 평가하는데 널리 사용되고 있는 주관적 설문 평가지(Beck의 우울척도, 상태-특성불안척도)의 지표 값과 심박 변이도의 파라미터 간의 상호-상관관계를 통계적으로 분석하여, 주관적 설문평가지의 지표 값을 대신 할 수 있는 심박 변이도 파라미터를 선정하기 위함이다. 그리고 심박 변이도 측정 시, 휴식 및 업무 상태를 인위적으로 유도하였고 각 유도된 상태에서의 심박 변이도를 이용하여 추출된 생리학적 특징값들과 주관적 설문 평가지의 지표 값의 상관관계를 통계적으로 분석하여 주관적 감성지표를 대체 할 수 있는 객관화된 정량적 지표를 도출하고자 한다. 본 논문의 결과로부터 얻을 수 있는 사실은 심박 변이도의 비 정규화 파라미터가 상태불안척도와 우울척도보다 특성불안척도와 더욱 높은 상관관계를 나타냈다는 점이다. 반면, 업무 상태와 휴식 상태의 비율인 정규화 파라미터 m_RRI(MeanRR interval), SDNN(Standard deviation of all NN intervals), LF(Low-Frequency), LF/HF(LF/HF ratio)는 특성불안척도, 우울척도보다 상태불안척도와 더 높은 상관관계를 나타냈다. 이 중, LF/HF는 상태불안뿐만 아니라, 특성불안을 반영할 수 있는 정량적인 생리학적 파라미터로 나타났다.
        4,000원
        89.
        2011.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigates variation in article use by Korean secondary school students of English. The study shows how two different tasks affect variation with respect to article types (a, the, and zero), proficiency level and the semantic feature, specificity. One task, a wide domain task, focused on grammar in general and the narrow domain task focused on articles. The statistical results showed that the subjects performed significantly better on the narrow domain task than on the wide domain task. The subjects showed significant differences among the three articles in the wide domain task, while they did not in the narrow domain task. The subjects performed significantly better with non-specific DPs (Determiner Phrases) than with specific DPs in the wide domain task, but reversed results were revealed in the narrow domain task. The present study presents some finding that grammatical domain plays a role as a variable for variability and shows that different tasks on the same research topic may produce different findings.
        5,400원
        91.
        2010.11 구독 인증기관·개인회원 무료
        해수면 관측치에서 평균해면과 조위를 제거한 것을 비조석해면변위라 한다. 비조석해면변위는 기압, 바람, 해수밀도 변화 등에 의해 만들어 진다. 연안이 나 항구에서 선박이 접안할 때나 낚시, 바다갈라짐 등 레저활동과 관광할 때, 조위는 예측이 가능하지만 비조석해면변위는 예측하기 어려워 안전를 위협할 수 있다. 한국연안의 비조석해면변위의 시공간적인 변동과 그 주요 요인을 알아 보고자 한다.
        95.
        2009.12 구독 인증기관 무료, 개인회원 유료
        Objectives: This research is about the reliability of pulse wave analyzer and heart rate variability analyzer which are often used in the oriental medical clinics. Materials and Methods: Pulse wave analyzer and heart rate variability analyzer's reliability were compared with other devices-bioelectrical impedance analyzer, thermographer and transcranial sonography-. For each device, they were measured three times in a row. Here are the results of measuring intraclass correlation coefficients between first and second, and the ones between first and third. Results: 1. For pulse wave analyzer, seven items are higher than 0.7 in intraclass correlation coefficients, fourteen items are higher than 0.5 and eleven items are higher than 0.5. 2. Heart rate variability analyzer show that an item is higher than 0.9 and two are higher than 0.7. three items are higher than 0.5 and four are lower than 0.5. 3. For bioelectrical impedance analyzer, thermographer and transcranial sonography, nineteen items are higher than 0.9 and two are higher than 0.7. Conclusion: Pulse wave analyzer and heart rate variability analyzer showed low test-retest reliability compared to the one of bioelectrical impedance analyzer, thermographer and transcranial sonography. But both of analyzer's reliability are more than midium quality. Diagnosis trough these analyzers have a utility value. More research will be needed. 
        4,200원
        97.
        2008.12 구독 인증기관 무료, 개인회원 유료
        This study was carried out to analyze any possible changes in the heart rate variability(HRV) of white-collar workers of a manufacturing firm based in Chollabuk-do Province when they are stressed due to their daily job performance and thereby to help them seek a more effective method of the management of their health and help them form more desirable habits of living by finding out how seriously his or her stresses from his or her job performance affect their quality of life(QOL). As a process of the above-mentioned manufacturer's plan to do an Oriental health examination on its white-collar workers, each of the workers of the firm was given a copy of questionaires. The questionaires carried questions regarding each of the workers' general characteristics, clinical history, health-related lifestyle and the QOL and each of the workers was asked to provide his answers to the questions listed on the questionaire. The examination progressed to measure any possible changes in the HRV of an individual worker. Among all of the questionaires filled out and collected from the workers, a total of 423 data were used as the data of the research except those that had answers which were not appropriate for the purpose of the research. The analysis of each of the workers' health related quality of life(HRQOL) showed that the younger, the lower the standard of education is, each of the subjects was found to tend to show a relatively higher QOL if only he is healthy. With regard to the worker's habits of living, those who exercise on a regular basis and who get a good sleep were also found to have a comparatively higher QOL With reference to the HRV, young workers, those who have spouses, those with a high level of academic background, those with a short work experience were found to tend to have a relatively higher HRV. As regards each worker's habits of living, those who do exercise on a regular basis were found to have a comparatively higher index of HRV. RMSSD was found to have an impact on workers' general health, on the other hand TP was found to have an impact on workers' role of emotion. This result was based on findings through analyzing interrelation between HRV and QOL that stresses have an impact on the QOL. Taking a look at the above results, it was learned that individual worker's efforts to promote his or her health, along with establish desirable habits of living, these two qualities are important methods to improve the quality of life. In addition, control of stresses is necessary to improve the QOL, which is possible through emotional stabilization.
        5,800원
        99.
        2008.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 역학적 특성이 우수하여 다양한 구조에 적용되고 있는 복합적층판에 대한 추계론적 유한요소해석 정식화를 제안한다. 정식화의 제시는 추계론적 수치해석기법 중 그 정확도가 매우 높은 것으로 알려져 있는 가중적분법에 기초하였다. 공간적 불확실성을 가지는 인수로는 두 재료축에 대한 탄성계수와 면내 전단탄성계수가 고려되었다. 이들 재료인수들은 독립적인 추계장함수로 모델링 되었으며, 이들 추계장이 구조거동에 미치는 영향은 지수함수형태의 자기 및 상호상관함수를 적용하여 산정하였다. 수치예제를 통하여 복합적층판이 등방성 및 이방성의 재료에 의한 판 구조에 비하여 거동의 변동계수가 낮음을 보여주었으며, 제안된 해석법의 검증을 위하여 몬테카를로 해석을 동시에 수행하고 그 결과를 상호 비교하였다.
        4,200원
        100.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because performance assessment such as a composition test introduces a range of factors that may influence the chances of success for a candidate on the test, those in charge of monitoring quality control for performance assessment programs need to gather information that will help them determine whether all aspects of the programs are working as intended. In the present study, generalizability theory (Brennan, 1992) was employed to examine the relative effects of various sources of variability on students" performance on an essay writing test and also to investigate the reliability of the assigned scores. The results showed that due to the largest effect associated with the students" writing ability and negligible effects associated with facets of measurement such as scoring criteria and ratings, the generalizability coefficient estimated for the writing test was high, suggesting that the test is a reliable measure of what it purports to measure, the students" writing ability.
        6,000원
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