• Communications for Statistical Applications and Methods
• /
• v.15 no.5
• /
• pp.709-717
• /
• 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.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.2
• /
• pp.300-306
• /
• 2000

In the present studies, we assessed the stability of active components and toxicological safety of irradiated Angelica gigas Nakai(Danggui). In order to confirm the stability of active components in the ${\gamma}$-irradiated roots of Danggui, the quantitative analysis of decursin and decursinol angelate of ${\gamma}$-irradiated sample was carried out by high performance liquid chromatographic (HPLC) methods using reverse phase columns and normal phase columns. From the root of Danggui, decursin and decursinol angelate were isolated by a silica gel column chromatography(toluene : ether (1 : 1), Hexane : EtOAc(15 : 1)). And then the structures were confirmed in the 1H and 13C-NMR analysis. The HPLC chromatograms of decursin and decursinol angelate in ${\gamma}$-irradiated Danggui were similar with those of non-irradiated sample. In the examination of in vitro genotoxicity of the water extract from ${\gamma}$-irradiated Danggui using Salmonella reversion assay(Ames test) and micronucleus test in Chinese hamster ovary (CHO) cells, mutagenicity was not exhibited in the two assays with or without metabolic activation. These resutls suggest that active components in the ${\gamma}$-irradiated Danggui should be stable and that the safety of ${\gamma}$-irradiated Danggui could be revealed in further test in vivo.

• Communications for Statistical Applications and Methods
• /
• v.12 no.3
• /
• pp.557-587
• /
• 2005

This paper elucidates the limiting Gaussian distribution of a class of rank order statistics {$T_N$} for two sample problem pertaining to empirical processes of the squared residuals from two independent samples of GARCH processes. A distinctive feature is that, unlike the residuals of ARMA processes, the asymptotics of {$T_N$} depend on those of GARCH volatility estimators. Based on the asymptotics of {$T_N$}, we empirically assess the relative asymptotic efficiency and effect of the GARCH specification for some GARCH residual distributions. In contrast with the independent, identically distributed or ARMA settings, these studies illuminate some interesting features of GARCH residuals.

• Korean Journal of Veterinary Research
• /
• v.47 no.4
• /
• pp.417-423
• /
• 2007

Serological surveillance programs in animal populations are becoming increasingly important to estimate prevalence of a specific disease and subsequently to document disease-free status in a region or a country. For these purposes, the programs need to be based on both theoretical and economical aspects from the designing phase. From Aujeszky's disease (AD)-eradication program point of view, group of animals (aggregates, herds) not individual animal is the more important sampling unit of concern. In this study the authors therefore attempted to compute an appropriate sample size tailored to a current surveillance program against AD, assuming that the goal of this program is either herd-level prevalence estimation or documentation of AD-freedom. For prevalence estimation, assuming a finite population with imperfect sensitivity (Se) and specificity (Sp) of ELISA kit for AD diagnosis, the number of herds present, expected herd prevalence, and desired accuracy for a certain level of confidence, sample size was estimated at herd-level in the first stage and individual animal-level in the second stage. A two-stage sampling design was used to calculate a sample size to indicate AD-freedom. In this instance, the computation was based on the possible detection of a predetermined prevalence at a certain herd-level Se and Sp. This study indicated that the sample size varied with predetermined confidence, tolerance, Se and Sp at herd- and animal-level, and within- and among-herd prevalence. In general, smaller sample size was required to estimate AD prevalence than to document of AD-freedom. Compared to individual-based samples, two-stage sampling strategy requires a larger sample size to show disease-freedom. Statistical considerations including herd-level test characteristics when designing surveillance program also are further discussed.

• Corrosion Science and Technology
• /
• v.4 no.1
• /
• pp.19-22
• /
• 2005

Two Au-Ag-Cu-Pd dental casting alloys (Au:12% and 20%) used. The test solutions used 0.9 % NaCl solution (isotonic sodium chloride solution), 0.9 % NaCl solution containing 1 % lactic acid, and 0.9 % NaCl solution containing 1 % lactic acid and 0.1 mol $dm^{-3}$ $Na_2S$. The surface of two samples in three sample solutions was not natural discoloration during one year. The alloy containing 12 % gold was easily alloyed and the composition was uniform comparing with the alloy containing 20 % gold. The rest potentials have not a little effect after three months. The kinds of metals could not definitely from the oxidation and reduction waves of metal on the cyclic voltammograms. The dissolutions of gold and palladium were 12 % Au sample in the 0.9 % NaCl solution containing 1 % lactic acid and 0.1 mol $dm^{-3}$ $Na_{2}S$. The pH of solution had an affect on dissolution of copper, and sulfur ion had an affect on dissolution of silver. The copper dissolved amount from 20 % gold sample was about 26 times comparing with that of 12 % gold sample in the 0.9 % solution containing 1 % lactic acid. Corrosion products were silver chloride and copper chloride in NaCl solution, and silver sulfide and copper sulfide in NaCl solution containing $Na_{2}S$.

• Journal of Korean Academy of Nursing
• /
• v.35 no.2
• /
• pp.419-427
• /
• 2005

Purpose: The purpose of this study was to identify the effects of a workbook program on percieved stress levels, maternal role confidence and breastfeeding practices of mothers of premature infants. Method: This study employed a quasi-experimental non-equivalent pre-and-post test to compare the two groups. Data was collected from 32 subjects from March 10. to September 5, 2003 at an NICU located in S. city. In the sample, fifteen mothers were in the experimental group and seventeen were in the control group. A workbook program was provided twice during a period from two-three days after the baby's admission to one week after the first intervention. The instruments used were the PSS and self confidence scale. Data was analyzed by means of frequency, SD, $x^2-test$, Fisher's exact test, Mann-Whitney test, and the Wilcoxon signed rank test. Result: There was a significant difference in perceived stress levels between the experimental and control group (U=2.366, p=.018). There was not a significant difference in maternal role confidence between the two groups (U=1.002, p=.316). There was a significant difference in breastfeeding practice between the two groups ($x^2=4.910$, p=.035). Conclusion: It is concluded that a program using a workbook has a positive effect on decreasing the perceived stress level and increasing breastfeeding practice.

• Environmental Mutagens and Carcinogens
• /
• v.15 no.2
• /
• pp.106-114
• /
• 1995

A method was developed to detect total mutagenicity of fried fish for S. typhimurium TA98, using Ames assay. Method described herein circumvented problems associated with the sample preparation for Ames assay, i.e., a multi-purification step of sample and interference with solvent residuals. Experiment A, the best method developed in the present study, consisted of two important steps: pH adjustment of the aqueous sample solution from fried fish samples to remove impurities, and simultaneous distillation extraction (SDE) for partially purified samples to remove volatile compounds from solvents. The procedure and results were described as below. Fillet of gizzard shad (Konosirus punctatus) fish sample fried for 10 min each side on the temperature-controlled fry-pan (210$\circ$C) was homogenized in an aqueous acidic solution (pH 2) with a homogenizer, followed by filtration through Celite. The tiltrate (pH 2), removed some impurities by extraction with chloroform:methanol (2:1, v/v) mixture, was adjusted pH to 10 and then centrifuged to remove precipitate. The ethylacetate extract from the tiltrate of pH 10 was rotoevaporated and purified by SDE apparatus for 2 hours. Experiment A revealed significantly higher revertants (1928 per 25 g fried sample) than other Experiment (B, C, or D) tested. Experiment A gave good results in the mutagenicity test of fried fish sample with few purification steps using only 25 g fried sample and 650 ml of solvents; and thus this method could be a useful tool for the screening the mutagenicity or antimutagenicity of other foods as well.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.246.1-246.1
• /
• 2003

Bioequivalence of two enalapril maleate tablets, formulation A and B, was evaluated according to the Korean Guidelines for Bioequivalence Test (KGBT 2001). Twenty healthy male volunteers (19∼27 years old) were randomly divided into two groups and a randomized 2x2 cross-over study was performed. Following oral administration of enalapril maleate tablets (20 mg dose), blood sample was taken at pre-determined time intervals and the concentrations of enalapril in plasma were determined using LC-MS. (omitted)

• Korean Journal of Clinical Laboratory Science
• /
• v.36 no.2
• /
• pp.127-130
• /
• 2004

Analytical sensitivity on TDM test is the lowest concentration that can be distinguished from background noise. The aim of study was to evaluate analytical sensitivity that is also referred to as the lower limit of detection(LLD) about difference between zero calibrator and isotonic saline sample. We tested for 10 days with zero calibrators and 0.85% saline samples while running trilevel control samples under control. Raw data divided by two groups calculated mean and standard deviation from two sample populations and analytical sensitivity by ${\bar{X}}+2SD$. In comparison with isotonic saline samples and zero calibrators, there were significant differences in phenytoin, phenobarbital and vancomycin, etc. Especially analytical sensitivity on phenytoin is at the same level as the upper limit of analytical measurement range with $40{\mu}g/mL$. We think the cause of this is matrix interference. In conclusion, we were sure that standard protocol for analytical sensitivity as lower limit of analytical measurement range on TDM test must be measured with zero standard rather than an isotonic saline sample and type 1 reagent DW for reducing matrix effects within interactions between different materials in a mixture.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.416-419
• /
• 2002

There are being two prominent studying for Digital Radiography. Direct and Indirect method of Digital Radiography are announced for producing high quality digital image. The one is using amorphous selenium as photoconductor and the other is using phosphor layer as a light conversion. But each two systems have strength and weakness such as high voltage and blurring effect. In this study, we investigated the electrical characteristic of $multi-layer\left(CaWO_{4}+a-Se \right)$ as a photoconductor according to the changing arsenic composition ratio. This is a basic research for developing of Hybrid digital radiography which is a new type X-ray detector. The arsenic composition ratio of a-Se compound is classified into 7 different kinds which have 0.1%, 0.3%, 0.5%, 1%, 1.5%, 5%, 10% and were made test sample throught thermo-evaporation. The phosphor layer of $CaWO_4$ was overlapped on a-Se using EFIRON optical adhesives. We measured the dark and photo current about the test sample and compared the electrical characteristic of the net charge and signal-to-noise ratio. Among other things, test sample of compound material of 0.3% arsenic showed good characteristic of $2.45nA/cm^2$ dark current and $357.19pC/cm^2/mR$ net charge at $3V/{\mu}m$.