• Journal of Korean Society for Quality Management
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• v.30 no.2
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• pp.130-151
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• 2002

This paper investigates the relation between the Process capability index(PCI) and the quality assurance level under various conditions. The effect of the off-targetness of the process mean, deviation from the nomality, the estimation error, and tile measurement error on the quality assurance level is evaluated. Various distributions such as the Student-t, the chi-square, the gamma, the Weibull, and the log-normal distributions are considered to evaluate the deviation from the nomality. The quality levels under abnormal conditions turn out to be severely different from that under the standard condition. We provide tables and graphs of the quality assurance level on various abnormal conditions. In order for the industry users to use the PCI properly, they should refer to the tables and graphs, especially when they are not certain about the standard assumptions on which the PCI depends.

• The Korean Journal of Applied Statistics
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• v.25 no.5
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• pp.733-741
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• 2012

The successful launch of Arirang satellites allow the acquisition of high resolution satellite imagery of Korean territory and enables the transition from the conventional cultivation area survey method to new image based methods adopted in advanced nations. In this study, we suggested reasonable sizes of the primary sampling unit and the secondary sampling unit for the satellite imagery based sampling design in 8 provinces preselected for this research. The PSU size was determined mainly in consideration of intracorrelation that shows the degree of homogeneity within each cluster and the efficiency of the image process. For the SSU size, we considered the relative standard error and the differences between the land cover maps produced by the Ministry of Environment and the satellite imagery processed by the National Statistical Office.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.632-637
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• 2011

A new tooth profile which is adjusted on the amount of addendum modification factor is proposed for reducing vibration and noise of gears. The transmission error of the new profile can be designed more uniformly than that of the standard involute profile. The basic concepts of tooth profile modification are to reduce the load in contact area and to find the appropriate profile modification factor for operation condition. In this study, gears were estimated to constructive safety of bending strength and contact strength durability by using ROMAX program, and were compared with results by design formula of AGMA standard.

• Communications for Statistical Applications and Methods
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• v.20 no.6
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• pp.455-466
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• 2013

In nested case-control studies, the most common way to make inference under a proportional hazards model is the conditional logistic approach of Thomas (1977). Inclusion probability methods are more efficient than the conditional logistic approach of Thomas; however, the epidemiology research community has not accepted the methods as a replacement of the Thomas' method. This paper promotes the inverse probability weighting method originally proposed by Samuelsen (1997) in combination with an approximate jackknife standard error that can be easily computed using existing software. Simulation studies demonstrate that this approach yields valid type 1 errors and greater powers than the conditional logistic approach in nested case-control designs across various sample sizes and magnitudes of the hazard ratios. A generalization of the method is also made to incorporate additional matching and the stratified Cox model. The proposed method is illustrated with data from a cohort of children with Wilm's tumor to study the association between histological signatures and relapses.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.4
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• pp.241-249
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• 2015

The purpose of this research is to develop the pattern recognition algorithm based on smart camera for inspection automation, and including external surface state of molding parts or optical parts. By performance verification, this development can be applied to establish for existing reflex data because inputting surface badness degree of scratch's standard specification condition directly. And it is pdssible to distinguish from schedule error of badness product and normalcy product within schedule extent after calculating the error comparing actuality measurement reflex data and standard reflex data mutually. The proposed technology cab be applied to test for masearing of the smallest 10 pixel unit. It is illustrated the relibility pf proposed technology by an experiment.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.20 no.4
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• pp.295-308
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• 2016

We propose a projection-based analysis of a new hybridizable discontinuous Gale-rkin method for second order elliptic equations. The method is more advantageous than the standard HDG method in a sense that the new method has higher-order accuracy and lower computational cost, and is more flexible. Notable distinctions of our new method, when compared to the standard HDG emthod, are that our method uses $L^2$-projection and suitable stabilization parameter depending on a mesh size for superconvergence. We show that the error for the solution of the equation converges with order p + 2 when we only use polynomials of degree p + 1 as a finite element space without postprocessing. After establishing the theory, we carry out numerical tests to demonstrate and ensure that the proposed method is effective and accurate in practice.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.159-164
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• 2018

An evaluation of various radiometric methods to analyze $^{226}Ra$ in water has been employed on a set of 10 standard solutions of different concentrations in the range of $1-10Bq/L^{-1}$. The analysis was carried out using well-established procedures by means of gamma-ray, alpha-particle and liquid scintillation spectrometry. The feasibility of the various methods has been quantified in terms of relative standard error and percentage error. Correlations between the various methods have been presented and discussed. In general, good agreement was found in the results of various methodologies, which assures the accuracy of the methods and allows for the validation of instrumentation and procedures. Of the different methods adopted here, a combined procedure for the determination of $^{226}Ra$ along with $^{228}Ra$ using Quantulus 1220 ultra-low level background liquid scintillation counting gave the most accurate results.

• Macromolecular Research
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• v.10 no.1
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• pp.13-17
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• 2002

An artificial neural network (ANN) was used to study the relationship between the glass transition temperature (T$_{g}$) and the structure of homopolymers. The input is very important for the ANN. In this paper, six kinds of input vectors were designed for the ANN. Of the six approaches, the best one gave the is T$_{g}$ of 251 polymers with a standard deviation of 8 K and a maximum error of 29 K. The trained ANN also predicted the T$_{g}$ of 20 polymers which are not included in the 251 polymers with a standard deviation of 7 K and a maximum error of 21 K. 21 K.

• Journal of the Korean Society of Tobacco Science
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• v.31 no.2
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• pp.95-106
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• 2009

Semiquantitative analysis by ICP-MS has proven to be a powerful tool for fast screening, in addition, it does not require the element of interest to be present in the calibration standard, making it especially useful for the analysis of unknown samples. In this study, seven cigarette samples were analyzed by the rapid semi-quantitative analysis method based on the ICP-MS. For each cigarette sample, cut tobacco, cigarette paper, filter (before and after smoking), and smoke condensate were analyzed. The accuracy of the analysis technique was evaluated by comparing results obtained from Calibration Check Standard(CCS) and calibration method. Relative Percentage Error(RPE) value of all elements measured for three CCS showed a stable result of less than ${\pm}20%$. Compared to full quantitative analysis by calibration method, the results for cigarette samples showed average error within ${\pm}15%$.

• YAKHAK HOEJI
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• v.48 no.1
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• pp.60-64
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• 2004

Near-infrared (NIR) spectroscopy was used to determine rapidly and nondestructively the content of ambroxol in intact ambroxol tablets containing 30 mg (12.5％ m/m nominal concentration) by collecting NIR spectra in range 1100-1750 nm. The laboratory-made samples had 10.3∼15.9％ m/m nominal ambroxol concentration. The measurements were made by reflection using a fiber-optic probe and calibration was carried out by partial least square regression (PLSR) with autoscaling. Model validation was performed by randomly splitting the data set into calibration and validation data set (7 samples as a calibration data set and 5 samples as a validation data set). The developed NIR method gave results comparable to the known values of tablets in a laboratorial manufacturing Process, standard error of calibration (SEC) and standard error of prediction (SEP) being 0.49％ and 0.49％ m/m respectively. The method showed good accuracy and repeatability NIR spectroscopic determination in intact tablets allowed the potential use of real time monitoring for a running production process.