• Title/Summary/Keyword: critical points

검색결과 871건 처리시간 0.024초

치과위생사의 치과용 아말감 수은에 대한 지식 및 행위 (Dental Hygienists' Knowledge on Dental Amalgam Mercury and Its Treatment Practice)

  • 신경희;양지연;권호근;신동천
    • Environmental Analysis Health and Toxicology
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    • 제22권3호
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    • pp.247-254
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    • 2007
  • This study was performed with the questionnaire survey on mercury knowledge and mercury exposure avoidance behavior, which was conducted among 1076 dental personnel in September, 2004. As for the factors effecting the mercury knowledge, it seems that they are closely related with the personnel's educational backgrounds, and their understandings of causing environmental hazardousness in the dental offices. And also, the factors effecting the behavior of mercury exposure avoidance are strongly connected with the knowledge points on mercury, the knowledge of air states in the dental clinic offices, the use of pincettes and gloves in squeezing, and rubber dam and gloves in mulling, the experience of environmental education on mercury, etc. In the survey, the higher points in mercury knowledge is closely related with the higher points in the behavior of mercury exposure avoidance. Nevertheless, the very fact that the lower points in the behavior among personnel takes on the aspect of the relatively higher points in knowledge on mercury may be understood that the generally acquired knowledge on mercury cannot be the critical factor of the behavior of mercury exposure avoidance.

Test for Discontinuities in Nonparametric Regression

  • Park, Dong-Ryeon
    • Communications for Statistical Applications and Methods
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    • 제15권5호
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    • pp.709-717
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    • 2008
  • The difference of two one-sided kernel estimators is usually used to detect the location of the discontinuity points of regression function. The large absolute value of the statistic imply discontinuity of regression function, so we may use the difference of two one-sided kernel estimators as the test statistic for testing null hypothesis of a smooth regression function. The problem is, however, we only know the asymptotic distribution of the test statistic under $H_0$ and we hardly expect the good performance of test if we rely solely on the asymptotic distribution for determining the critical points. In this paper, we show that if we adjust the bias of test statistic properly, the asymptotic rules hold for even small sample size situation.

Drive Point Dynamic Stiffness(DPDS)분석을 통한 Road noise 개선 (Road noise improvement using Drive Point Dynamic Stiffness(DPDS) estimation)

  • 이상윤;김영호;이근수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 추계학술대회논문집
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    • pp.612-616
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    • 2007
  • This paper describes a procedure to improve road noise using DPDS estimation. We can estimate a body local stiffness at chassis mounting point where the path of road input vibration by DPDS with experiment and FE simulation. DPDS result from FE model has a good correlation with experiment data. FE model DPDS shows weak points among chassis mounting points. Body panel thickness and shape were changed to meet DPDS target. Improved DPDS of critical points makes a road noise level lower.

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MORSE INDEX OF COMPACT MINIMAL SURFACES

  • Hong, Suk Ho;Park, Ki Sung
    • Korean Journal of Mathematics
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    • 제6권1호
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    • pp.77-85
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    • 1998
  • In this paper we study the Hessian at critical points of energy function on Teichm$\ddot{u}$ller space T(R) and apply it to the index of minimal surfaces.

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Amplitude Dependency of Damping in Buildings and Critical Tip Drift Ratio

  • Tamura, Yukio
    • 국제초고층학회논문집
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    • 제1권1호
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    • pp.1-13
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    • 2012
  • The importance of appropriate use of damping evaluation techniques and points to note for accurate evaluation of damping are first discussed. Then, the variation of damping ratio with amplitude is discussed, especially in the amplitude range relevant to wind-resistant design of buildings, i.e. within the elastic limit. The general belief is that damping increases with amplitude, but it is emphasized that there is no evidence of increasing damping ratio in the very high amplitude range within the elastic limit of main frames, unless there is damage to secondary members or architectural finishings. The damping ratio rather decreases with amplitude from a certain tip drift ratio defined as "critical tip drift ratio," after all friction surfaces between primary/structural and secondary/non-structural members have been mobilized.

중점개발연구개발사업의 추진전략의 설계 및 현화에 관한 연구 (A Study on the Design of Implemental Strategy and Present States of Critical Technology-21 Research Program)

  • 이상엽;류영수
    • 기술경영경제학회:학술대회논문집
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    • 기술경영경제학회 2000년도 제17회 하계학술발표회 논문집
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    • pp.243-263
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    • 2000
  • Several strategic system are prepared and designed for the critical technology-21, which is a kind of national R&D program and is based on the $\ulcorner$Special Act for Innovation of Science and Technology$\lrcorner$from early of 1998. Various valuables in social-technological, political-technological and econo- technological points and a new R&D planning method, "scenario method, " are considered and tried for overcoming the socio-economical difficulties of country and strategies of this program which is become a implementation skeleton of critical technology-21 are summarized as a implemental model of national R&D program. And present states, sub-projects of same research program are analyzed by type of research group and valuables.

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실린더형 패드와 평판 시험편간 프레팅 피로의 접촉폭 크기효과에 관한 평가 (Estimation on a Contact Size Effect in Fretting Fatigue Between Cylindrical Pad and Flat Specimen)

  • 김진광;조상봉
    • 한국정밀공학회지
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    • 제25권6호
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    • pp.116-125
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    • 2008
  • In general, fretting is a contact damage process due to micro-slip associated with small amplitude oscillatory movement between two surfaces in contact. Previous studies in fretting fatigue have observed a contact size effect related to contact width. The volume-averaging method of theoretically predicted contact stress fields was required to emulate experimental trends and to predict the observed contact size effects. This contact size effect is captured by the mean values of stresses and strains at the element integration points of FE model and two critical plane models (SWT, FS) in the present paper. It is shown that crack nucleation and fretting fatigue life can be predicted by the FE-based critical plane models.