• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.55.1-55.12
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• 2020

Objectives: This study investigated the effects of physically damaged and resin-contaminated tips on radiant emittance, comparing them with new undamaged, non-contaminated tips using 3 pieces of spectrophotometric laboratory equipment. Materials and Methods: Nine tips with damage and/or resin contaminants from actual clinical situations were compared with a new tip without damage or contamination (control group). The radiant emittance was recorded using 3 spectrophotometric methods: a laboratory-grade thermopile, a laboratory-grade integrating sphere, and a portable light collector (checkMARC). Results: A significant difference between the laboratory-grade thermopile and the laboratory-grade integrating sphere was found when the radiant emittance values of the control or damaged/contaminated tips were investigated (p < 0.05), but both methods were comparable to checkMARC (p > 0.05). Regardless of the method used to quantify the light output, the mean radiant emittance values of the damaged/contaminated tips were significantly lower than those of the control (p < 0.05). The beam profile of the damaged/contaminated tips was less homogeneous than that of the control. Conclusions: Damaged/contaminated tips can reduce the radiant emittance output and the homogeneity of the beam, which may affect the energy delivered to composite restorations. The checkMARC spectrophotometer device can be used in dental offices, as it provided values close to those produced by a laboratory-grade integrated sphere spectrophotometer. Dentists should assess the radiant emittance of their light-curing units to ensure optimal curing in photoactivated, resin-based materials.

• Journal of applied mathematics & informatics
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• v.5 no.3
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• pp.669-690
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• 1998

In this paper we develop a new theory of adjoint and symmetric method in the class of general implicit one-step fixed-stepsize methods. These methods arise from simple and natral def-initions of the concepts of symmetry and adjointness that provide a fruitful basis for analysis. We prove a number of theorems for meth-ods having these properties and show in particular that only the symmetric methods possess a quadratic asymptotic expansion of the global error. In addition we give a very simple test to identify the symmetric methods in practice.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.125-132
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• 2001

IBM developed the MPI-IO, we call it MPI-2, on the General Parallel File System. We designed and implemented various Matrix Multiplication Benchmarks to evaluate its performances. The MPI-IO on the General Parallel File System shows four kinds of data access methods : the non-collective and blocking, the collective and blocking, the non-collective and non-blocking, and the split collective operation. In this paper, we propose benchmarks to measure the IO time and the computation time for the data access methods. We describe not only its implementation but also the performance evaluation results.

• The Journal of the Acoustical Society of Korea
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• v.26 no.1E
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• pp.27-32
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• 2007

Hydraulic actuator and electro-magnetic liner actuator have been used as typical active vibration control methods. However these methods have many kinds of disadvantages such as causing space limit, difficult maintenance, complicate structures, etc. The purpose of this paper was to study on the possibility of active vibration control using piezoelectric transducer. Piezoelectric transducer generated a vibration and GIC (General Impedance Converter) amplifier was adopted to give adjustable vibration signal to transducer and high amplitude of vibration. Resonance frequency of piezoelectric transducer was controlled by GIC amplifier and higher amplitude of vibration was achieved. Finally active vibration control using piezoelectric transducer was performed.

• The Korean Journal of Applied Statistics
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• v.11 no.2
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• pp.287-302
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• 1998

Saddlepoint approximation to the distribution function of sample mean(Daniels, 1987) is extended to the case of general statistic in this paper. The suggested approximation methods are applied to derive the approximations to the distributions of some statistics, including sample valiance and studentized mean. Some comparisons with other methods show that the suggested approximations are very accurate for moderate or small sample sizes. Even in extreme tail the accuracies are also maintained.

• International Journal of Computer Science & Network Security
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• v.24 no.4
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• pp.44-50
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• 2024

This paper offers an overview of matrix formation and calculation techniques within the framework of General Linear Models (GLMs). It takes a sequential approach, beginning with a detailed exploration of matrix formation and calculation methods in regression analysis and univariate analysis of variance (ANOVA). Subsequently, it extends the discussion to cover multivariate analysis of variance (MANOVA). The primary objective of this study was to provide a clear and accessible explanation of the underlying matrices that play a crucial role in GLMs. Through linking, essentially different statistical methods, by fundamental principles and algebraic foundations that underpin the GLM estimation. Insights presented here aim to assist researchers, statisticians, and data analysts in enhancing their understanding of GLMs and their practical implementation in diverse research domains. This paper contributes to a better comprehension of the matrix-based techniques that can be extended to GLMs.

• The Korean Journal of Health Service Management
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• v.11 no.4
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• pp.17-28
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• 2017

Objectives : This study analyzed job performance in local area general hospitals to look for measurable effects from educational training and/or organizational communication. Methods : For the purposes of this study, a survey was conducted of general hospital employees from 29 hospitals in Gwangju and Jeonnam. The survey period was August 22 - September 30, 2016, and 1,004 responses were used in the final analysis. Results : This study revealed that certain aspects of communication (upward,downward,vertical,orinformal) had significant effects on job satisfaction, learning transfer, and general performance. Conclusions : To improve job performance in general hospitals, employers must improve overall satisfaction by improving upon job training and internal communication. Specifically, training should be better connected to learning transfer and organizational design must encourage active communication between employees.

• Journal of The Korean Radiological Technologist Association
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• v.30 no.1
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• pp.28-35
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• 2004

Purpose : The purpose of this study is to compare the job satisfaction between regular radiologists and non-regular radiologists in general hospital and to research the factors of affecting job satisfaction. Materials and Methods : The subject is 120 radi

• International Journal of Reliability and Applications
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• v.2 no.2
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• pp.131-135
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• 2001

Two general methods of construction leading to several series of universally optimal block designs for complete diallel crosses are provided in this paper. A method of constructing variance balance designs is also given.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.48.3-48.3
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• 2020

Using redshift-space distortion, I reconstruct the growth history as a smooth function using model independent methods. Assuming general relativity, I obtain the expansion history independently of the dark energy model, and test it to the supernovae data. The results are consistent with general relativity as gravity and the cosmological constant as dark energy, although interestingly negative dark energy densities are not ruled out by the data at z~0.7 to 1.