• Journal of Korean Society for Quality Management
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• v.24 no.3
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• pp.65-76
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• 1996

This paper is concerned with designing $\bar{X}$-control charts when an estimate error may be Inevitable. Estimate error offen can not be avoided in estimating or measuring the parameter values of the cost model for the control charts. The bounded interval is a common practice to compensate for inherent estimating error. We introduce the 'propagation of error technique to deal with the economic design of the $\bar{X}$-control charts with imprecise information on the cost model parameters. A numerical example is presented to show· its ability in the economic design of $\bar{X}$-control charts.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.341-343
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• 2012

This study introduces a method for computation of process and operation gap in the specific construction operation(i.e., RC frame construction applying a block-grouping scheme) using CYCLONE-based simulation modeling and analysis technique. Since uncertainty of construction environment exists, a thoughtful production planning is required to effectively deal with a risk resulting in schedule delay in advance. This study presents the concepts of a time delay occurred in a process level and operation level in a operation model, and a method of measuring gap-times in each level while the simulation progresses. It helps a site manager to decide how many segmentation in a construction block is suitable for eliminating unproductive time-delays under the constrained resources (e.g., laborer, equipment). A case study presents a network model representing a three segmented RC frame work, and result obtained from the simulation experiment.

• Natural Product Sciences
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• v.17 no.3
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• pp.212-215
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• 2011

In the course of screening anti-adipogenic activity of natural products employing the preadipocyte cell line, 3T3-L1 as an in vitro assay system, the EtOAc fraction of the stem barks of Acer tegmentosum Maxim (Aceraceae) showed significant inhibitory activity on adipocyte differentiation as assessed by measuring fat accumulation using Oil Red O staining. Activity-guided fractionation led to the isolation of active constituent, (+)-catechin. (+)-Catechin showed inhibitory activity on adipocyte differentiation in dose-dependent manner. Further studies with interval treatment demonstrated that (+)-catechin exerted inhibitory activity on adipocyte differentiation via acting on early stage of adipogenesis. Our present study also showed that (+)-catechin significantly inhibited the preadipocyte proliferation. Taken together, these results suggest that (+)-catechin, a constituent of A. tegmentosum might contribute the anti-adipogenic activity of A. tegmentosum.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2A
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• pp.196-201
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• 2010

Measurement of Quality of Service (QoS) parameters and its statistical analysis becomes a key issue for Mobile WiMAX service providers to manage the converged network efficiently and to support end-to-end QoS. In this paper, we investigate the population distribution of end-to-end one-way delay which is the most important QoS parameter in Mobile WiMAX networks. The samples are analyzed with Chi-Square Goodness-of-Fit test, Kolmogorov-Smirnov (K-S), and Anderson-Darling (A-D) test to verify the distribution of parent population. The relation with confidence level and the minimum number of sample size is also performed for logistic distribution. The statistical analysis is a promising approach for measuring the performance Mobile WiMAX networks.

• Journal of the Korean Chemical Society
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• v.7 no.3
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• pp.203-206
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• 1963

The eddy diffusion in the pulsed wetted wall column, where the spherical balls are consecutively arrayed along the axis of the column and turbulence is caused around the balls by pulsation, has been studied both theoretically and experimentally. A diffusion equation is solved for a longitudinal column where a concentration impulse is given at the top of the column, and the experimental results, which are the impulse response measurements at the half of the total height of the column, have shown a good agreement with the developed theory. A method of measuring the eddy diffusivity, which is based on the slope of concentration vs. time in the particular interval of concentration, is proposed and the measured diffusivity is used as a criterion of comparing the theory and the experiment. The eddy diffusion is remarkably increased as the amplitude and the frequency of the pulsation increase but the increasing rate is decreased as the pulsation increases.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.183-185
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• 1995

We present a visual programming system for signal analysis; it allows the user to construct signal processing algorithms by assembling visually fundamental signal processing blocks, and to observe the processed signals as well as the original signals in detail by magnifying a portion and measuring the time interval and amplitude between two points. Each fundamental signal processing block is implemented as an independent dynamically linked library module. Therefore, the user can expand the system processing capability by simply adding dynamically linked library modules without restructuring the entire system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.1-7
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• 2001

It is very important to test circular motion accuracy of NC machine tools as it affects all other machines machined by them in industries. In this paper, it has become possible to detect errors of linear displacement of radial directions for circle tar motion accuracy test using newly assembled magnetic type of linear scale so called Magnescale ball-bar system. It has also organized computer program systems using tick pulses come out from computer for getting error motion data at colt start time interval in circular motion test on NC lathe. Error data gotten from test is expressed to plots and analysed to numerics by various statistical treatments.

• Journal of Magnetics
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• v.15 no.4
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• pp.221-224
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• 2010

A laboratory sensor model was designed, constructed, and tested based on a newly proposed working principle of magnetic field detection. The principle of sensing employed a time-coded method in correlation with exploiting the advantageous features of the GMI effect. The sensor demonstrated a sensitivity of $10\;{\mu}s/{\mu}T$ in the field range of ${\pm}100\;{\mu}T$. The sensing element in the form of an amorphous thin wire, $100\;{\mu}m$ in diameter ${\times}50\;mm$ long, was fit into a small field modulation coil of 60 mm length. At a magnetic field modulation in the range of hundreds of Hz, the change in time interval of two adjacent GMI voltage peaks was linearly related to the external magnetic field to be measured. This mechanism improved the sensor linearity of the GMI sensor to better than 0.2% in the measuring range of ${\pm}100\;{\mu}T$.

• Journal of Magnetics
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• v.14 no.3
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• pp.129-131
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• 2009

A time-coded giant magnetoimpedance (GMI) magnetic field sensor was investigated and designed. The successfully constructed and tested laboratory model demonstrated a sensitivity of 5 ${\mu}s/{\mu}T$ in the field range of $\pm200{\mu}T$. The sensing element in the form of an amorphous thin wire, 100 mm in diameter $\times50$ mm long, was fit into a small field modulation coil of 60 mm length. At a magnetic field modulation in the range of hundreds of Hz, the change in time interval of two adjacent GMI voltage peaks was linearly related to the external magnetic field to be measured. This mechanism improved the sensor linearity to better than 0.3% in the measuring range of $\pm200{\mu}T$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.6
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• pp.276-280
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• 2001

This paper presents the result of a study on the distribution characteristics of salt contaminants in the west coast region, from Inchon to Yearsoo, of South Korea. To evaluate the distribution characteristics of salt contaminants, we had measured the equivalent salt deposit density(ESDD) with brush wiping method for thirteen month(from May 1999 to June 2000). Under the consideration on the measuring interval and method, normalization method was applied for the ESDD data. Besides the measurement, the chemical analysis (chromatography) was carried to investigate the relationship, between the electrical property and the amount of specific ingredient, such as sodium, magnesium and chloride. From the result, we could get the representative value of contamination for each site and distribution characteristics of salt contaminants with the distance from sea in the west coast.