• Genomics & Informatics
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• 제10권2호
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• pp.117-122
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• 2012

A sample size with sufficient statistical power is critical to the success of genetic association studies to detect causal genes of human complex diseases. Genome-wide association studies require much larger sample sizes to achieve an adequate statistical power. We estimated the statistical power with increasing numbers of markers analyzed and compared the sample sizes that were required in case-control studies and case-parent studies. We computed the effective sample size and statistical power using Genetic Power Calculator. An analysis using a larger number of markers requires a larger sample size. Testing a single-nucleotide polymorphism (SNP) marker requires 248 cases, while testing 500,000 SNPs and 1 million markers requires 1,206 cases and 1,255 cases, respectively, under the assumption of an odds ratio of 2, 5% disease prevalence, 5% minor allele frequency, complete linkage disequilibrium (LD), 1:1 case/control ratio, and a 5% error rate in an allelic test. Under a dominant model, a smaller sample size is required to achieve 80% power than other genetic models. We found that a much lower sample size was required with a strong effect size, common SNP, and increased LD. In addition, studying a common disease in a case-control study of a 1:4 case-control ratio is one way to achieve higher statistical power. We also found that case-parent studies require more samples than case-control studies. Although we have not covered all plausible cases in study design, the estimates of sample size and statistical power computed under various assumptions in this study may be useful to determine the sample size in designing a population-based genetic association study.

• 복식문화연구
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• 제14권4호
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• pp.609-624
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• 2006

The purpose of this study is to give the guideline to the pattern designing by supplying various images of the transformed shape of tailored collar with the location and angle of gorge line and laying measurement of the tailored collar while designing the tailored collar. The results of this study are as follows : Images of the sample at the case of 1cm of laying measurement looks 'urban', 'light', 'sharp', 'young', 'fashionable' and 'narrow' than that at the case of 7cm. When the laying measurement increases, the image of the sample looks more 'classical' and 'boorish'. The image of the sample 'light', 'sensuous' and 'young' at the case of sample of which laying measurements of the collar was 3cm. Second, at the case of sample whose laying measurements of the collar was 5cm, it was shown that the low location of gorge line made the image of the sample 'soft' and 'short'. On the other hand the image of the sample looked 'hard', 'keen' and 'long' by the high location of gorge line. Third, at the case of sample of which laying measurements of the collar was 7cm, low location of gorge line made the image of the sample look short. However, normal location of gorge line made the image of the sample looked 'fashionable'. The images of the samples of which laying measurements of the collar were 3cm, 5cm and 7cm, respectively, had changed with the angle of gorge line. First, the high angle of gorge line made the image of the sample 'rigid' and 'keen' at the case of sample of which laying measurements of the collar was 3cm. The high angle of gorge line made the image of the sample looked 'boorish' and 'singular'.

• Journal of Trauma and Injury
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• 제37권1호
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• pp.67-73
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• 2024

Purpose: Posttraumatic stress disorder (PTSD) is prevalent and is associated with protracted recovery and worse outcomes after injury. This study compared PTSD prevalence using the PTSD Checklist for DSM-5 (PCL-5) with the prevalence of PTSD risk using the Injured Trauma Survivor Screen (ITSS). Methods: Adult trauma patients at a level I trauma center were screened with the PCL-5 (sample 1) at follow-up visits or using the ITSS as inpatients (sample 2). Results: Sample 1 (n=285) had significantly fewer patients with gunshot wounds than sample 2 (n=45) (8.1% vs. 22.2%, P=0.003), nonsignificantly fewer patients with a fall from a height (17.2% vs. 28.9%, P=0.06), and similar numbers of patients with motor vehicle collision (40.7% vs. 37.8%, P=0.07). Screening was performed at a mean of 154 days following injury for sample 1 versus 7.1 days in sample 2. The mean age of the patients in sample 1 was 45.4 years, and the mean age of those in sample 2 was 46.1 years. The two samples had similar proportions of female patients (38.2% vs. 40.0%, P=0.80). The positive screening rate was 18.9% in sample 1 and 40.0% in sample 2 (P=0.001). For specific mechanisms, the positive rates were as follows: motor vehicle collisions, 17.2% in sample 1 and 17.6% in sample 2 (P>0.999); fall from height, 12.2% in sample 1 and 30.8% in sample 2 (P=0.20); and gunshot wounds, 39.1% in sample 1 and 80.0% in sample 2 (P=0.06). Conclusions: The ITSS was obtained earlier than PCL-5 and may identify PTSD in more orthopedic trauma patients. Differences in the frequency of PTSD may also be related to the screening tool itself, or underlying patient risk factors, such as mechanism of injury, or mental or social health.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1021-1021
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• 2001

Sample presentation, which means how to set samples to an NIR instrument, is very important in Near Infrared (NIR) Spectroscopy. When sample presentation is not suitable for the samples that you use, very good spectra can not be obtained even if you use a sophisticated NIR instrument. In my presentation, various NIR sample presentations for agricultural products such as intact fruits, single grains, vegetable juice and the others will be explained. In case of peaches with thin peel, the fiber optics of Interactance can be used. However, the fiber optics are not suitable for oranges with relatively thick peel. In this case, transmittance method is useful. As for a small sample such as single grains, a specially designed cell is needed. The cell in transmittance mode has been developed and then applied to single kernels of rice and soybean. In this case we also used the fiber optics. As regards liquid type of sample, a cuvette cell made of quartz in transmittance mode is popular. However, it is time-consuming to wash and dry it. In order to compensate this disadvantage the sample presentation using normal test tubes as sample cells have been developed and applied to milk, rumen juice and urine of a milking cow. An individual test tube can be used for each sample if you use the calibration equation with sample cell compensation. The test tube cell has also been applied to spinach juice for determination of undesirable constituents. It is concluded that sample presentation is most important for NIR Spectroscopy.

• Genomics & Informatics
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• 제4권2호
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• pp.51-56
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• 2006

In planning a genetic association study, it is necessary to determine the number of samples to be collected for the study in order to achieve sufficient power to detect the hypothesized effect. The case-control design is increasingly used for genetic association studies due to the simplicity of its design. We review the methods for the sample size and power calculations in case-control genetic association studies between a marker locus and a disease phenotype.

• 한방안이비인후피부과학회지
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• 제16권1호
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• pp.63-76
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• 2003

This Experiment was conducted to investigate the hemostatic effects of Guipitang and Guipitangjiaweifang. For this purpose, the effects of the crude extracts on the platelet count. prothrombin time, fibrinogen level and partial prothromboplastin time were estimated. The rats were divided into normal group, control group and experimental group. Control group was administrated normal saline and experimental group was divided into Sample 1 (Guipitang) and Sample 2 (Guipitangjiaweifang). The results obtained were as follows : 1. The platelet count was significantly increased in both of two samples as compared with the control group. 2. The prothrombin time was significantly shortened in case of Sample 2. however there were no significant changes in case of Sample 1 as compared with the control group. 3. The fibrinogen level was significantly increased in case of Sample 1. however there were no meaningful changes in case of Sample 2 as compared with the control group. 4. The partial prothromboplastin time was significantly shortened in both of two samples as compared with the control group. According to above results. it is supposed that Guipitang and Guipitangjiaweifang have the hemostatic effects in experimental animals.

• Journal of the Korean Data and Information Science Society
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• 제28권5호
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• pp.981-999
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• 2017

단순확률모형을 고려하는 표준관리도에서는 표본간 분산을 고려하지 않고 공정분산을 추정한다. 표본간 분산이 존재하는 경우에는, 공정분산이 과소추정된다. 공정분산이 과소추정되면 좁아진 관리한계로 인해 관리도의 민감도는 향상되지만 과도한 오경보율을 발생시킨다. 이 논문에서는 공정모형으로 분산성분모형, 즉 변동의 원인을 표본내 분산과 표본간 분산으로 구분하는 확률모형을 고려한다. 관리한계는 표본내 분산과 표본간 분산을 모두 사용하여 설정하고 그에 따른 평균런길이를 통하여 효율을 살펴 보았다. 관리형태는 가장 널리 사용되는 ${\bar{X}}$, EWMA, CUSUM 관리도를 고려하였다. 관리한계 설정에서 표본내 분산만을 사용한 경우 (Case I)와 표본간 분산도 함께 사용한 경우 (Case II)를 통해 관리도의 효율을 비교하였다. 또한, 공정 모수가 주어진 경우와 추정된 두 경우에 대해서도 관리도의 효율을 비교하였다. 그 결과, 표본간 분산이 증가할 때 Case I의 오경보율은 급격히 증가한 반면 Case II의 경우에는 동일하게 유지됨을 알 수 있었다.

• Genomics & Informatics
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• 제7권3호
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• pp.148-151
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• 2009

Generally, larger sample size leads to a greater statistical power to detect a significant difference. We may increase the sample size for both case and control in order to obtain greater power. However, it is often the case that increasing sample size for case is not feasible for a variety of reasons. In order to look at change in power as the ratio of control to case varies (1:1 to 4:1), we conduct association tests with simulated data generated by PLINK. The simulated data consist of 50 disease SNPs and 300 non-disease SNPs and we compute powers for disease SNPs. Genetic Power Calculator was used for computing powers with varying the ratio of control to case (1:1, 2:1, 3:1, 4:1). In this study, we show that gains in statistical power resulting from increasing the ratio of control to case are substantial for the simulated data. Similar results might be expected for real data.

• 한국산업보건학회지
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• 제6권2호
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• pp.301-312
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• 1996

This study was performed to search a optimal analyzing method of cadmium in whole-blood. Cadmium was determined by graphite furnace atomic absorption spectrometry(GFAAS). We investigated the effect of ashing temperature on the absorbance of cadmium in a simple dilution(ten-fold) method with triton X-100 and matrix modifier methods treated with $NH_4H_2PO_4$(1 and 3%) and $Pd(NO_3)_2$(0.00l and 0.005%) as matrix modifier. We also compared the reported reference values of standard blood with values resulted from optimal analyzing conditions of this study. In case of a simple dilution method, when ashing temperature was set at $450^{\circ}C$, the absorbance of sample and background were $0.334{\pm}0.012$ and $1.382{\pm}0.245$, respectively. Background level was higher than the value(0.8) that can be corrected by $D_2$ background correction method. As ashing temperature was rised to $500^{\circ}C$, the absorbance of sample and background were $0.178{\pm}0.008$ and $0.711{\pm}0.223$ respectively. The higher ashing temperature($450^{\circ}C-650^{\circ}C$) was, the lower the absorbance of sample was. In case of a matrix modifier method with $NH_4H_2PO_4$(1 and 3%), when ashing temperature was rised from $500^{\circ}C$ to $650^{\circ}C$, the absorbance of sample slightly changed. The absorbances of sample at $600^{\circ}C$ were $0.230{\pm}0.017$ and $0.137{\pm}0.012$, respectively. These values were larger than that of simple dilution method. But the absorbance of background was higher than the level that can be corrected by $D_2$ method. In case of a matrix modifier method with $Pd(NO_3)_2$(0.001 and 0.005%), the absorbance of sample and background were higher than those of other methods and were stable and reproducible. When ashing temperature was over $550^{\circ}C$, the absorbance of sample was significantly decreased. In case of 0.005% $Pd(NO_3)_2$ carbon residue remained in graphite tube affected the absorbance of sample and background. From these results, We propose that in case of a simple dilution(ten-fold) method with triton X-100 ashing temperature must be maintained below $400^{\circ}C$. In order to diminish the absorbance of background, the alternative method is attenuation of injection volume or multiplication of dilution ratio. We recommend $Pd(NO_3)_2$ than $NH_4H_2PO_4$ as a matrix modifier. In case of a matrix modifier method with $Pd(NO_3)_2$ ashing temperature might be maintained below $550^{\circ}C$.

• 한국정보시스템학회지:정보시스템연구
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• 제27권3호
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• pp.63-80
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• 2018

Purpose The purpose of this study is to build a machine learning-based customer classification model to promote customer expansion effect of the free sample promotion. Specifically, the proposed model classifies potential target customers who are expected to purchase the products included in the free sample promotion after receiving the free samples. Design/methodology/approach This study proposes to build a customer classification model for determining customers suitable for providing free samples by using various machine learning techniques such as logistic regression, multiple discriminant analysis, case-based reasoning, decision tree, artificial neural network, and support vector machine. To validate the usefulness of the proposed model, we apply it to a real-world free sample-based target marketing case of a Korean major cosmetic retail company. Findings Experimental results show that a machine learning-based customer classification model presents satisfactory accuracy ranging from 70% to 75%. In particular, support vector machine is found to be the most effective machine learning technique for free sample-based target marketing model. Our study sheds a light on customer relationship management strategies using free sample promotions.