• Title/Summary/Keyword: sample number

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Calculation of Sample Size in Clinical Trials (임상 연구에서 연구 표본수의 산출)

  • Lee, Hyo-Jin;Kim, Yang-Soo;Park, In
    • Clinics in Shoulder and Elbow
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    • v.16 no.1
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    • pp.53-57
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    • 2013
  • Purpose: This review aims to explain the definition and basic principle of statistical analysis and to clarify statistical issues related to the sample size calculation. Materials and Methods: Many formulas are available that can be applied for different types of data and study design. Results: The sample size is the number of patients or other experimental units that need to be calculated prior to the study. Determining the appropriate sample size is required to answer the research question. Conclusion: Caution is needed when applying formula for the calculation of the sample size, as it is sensitive to error and even small differences in selected parameters can lead to large differences in the sample size.

A noble Sample-and-Hold Circuit using A Micro-Inductor To Improve The Contrast Resolution of X-ray CMOS Image Sensors (X-ray CMOS 영상 센서의 대조 해상도 향상을 위해 Micro-inductor를 적용한 새로운 Sample-and-Hold 회로)

  • Lee, Dae-Hee;Cho, Gyu-Seong;Kang, Dong-Uk;Kim, Myung-Soo;Cho, Min-Sik;Yoo, Hyun-Jun;Kim, Ye-Won
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.49 no.4
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    • pp.7-14
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    • 2012
  • A image quality is limited by a sample-and-hold circuit of the X-ray CMOS image sensor even though simple mos switch or bootstrapped clock circuit are used to get high quality sampled signal. Because distortion of sampled signal is produced by the charge injection from sample-and-hold circuit even using bootstrapped. This paper presents the 3D micro-inductor design methode in the CMOS process. Using this methode, it is possible to increase the ENOB (effective number of bit) through the use of micro-inductor which is calculated and designed in standard CMOS process in this paper. The ENOB is improved 0.7 bit from 17.64 bit to 18.34 bit without any circuit just by optimized inductor value resulting in verified simulation result. Because of this feature, micro-inductor methode suggested in this paper is able to adapt a mamography that is needed high resolution so that it help to decrease patients dose amount.

An Analysis of the Constraints of Residential Mobility (주거이동 제약 요인 분석)

  • Yang, Se-Hwa;Kim, Myo-Jung
    • Journal of Families and Better Life
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    • v.28 no.2
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    • pp.27-37
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    • 2010
  • The purpose of the study was to analyze the constraints that are normally experienced before moving in the context of the household characteristics of households that had recently moved to newly-built apartments. The data for the analysis was collected through a self-administered questionnaire from July 1, 2008 to August 10, 2008. The sample consisted of 251 households in Ulsan living in an apartment complex who had moved within a year. The data from the sample was analyzed by descriptive statistics, factor analysis, and analysis of variance with Duncan's multiple range tests. The results are as follows. The constraints were categorized into information gathering, attractive housing characteristics, expectations of residential mobility, housing development and policies, and resources. Overall, the constraints did not have a huge impact on the performance of the residential mobility of the sample households. Resources, however, were the most influential factors among the five constraints followed by attractive housing characteristics, information gathering, etc. The constraints varied based on the demographic characteristics, such as the household size, duration of marriage, age of the household head, and the socio-economic characteristics, such as the education level of the household head, household income, and the number of mobility. As the number of family members increased, the age of the household head went up, or the level of education went down, the constraints on information gathering were affected in terms of performing residential mobility. Households with a middle aged head with a professional occupation were more constrained by the attractive characteristics of the housing. The impact of the resources related constraints was significantly different based on the number of family members, marriage duration, and the household head's age and occupation, and the number of mobility.

A New Analytical Method to Determine the Purity of Synthetic Fluorophores using Single Molecule Detection Technique

  • Song, Nam-Yoong;Kim, Hyong-Ha;Park, Tae-Sook;Yoon, Min-Joong
    • Journal of Photoscience
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    • v.12 no.2
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    • pp.87-93
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    • 2005
  • A new assay technique to distinguish between pure compounds and the isomeric mixtures has been suggested using single molecule (SM) fluorescence detection technique. Since the number of emission spots in a fluorophorespread film prepared from a genuine dye solution was determined by experimental condition, the deviation of spot numbers from the expected values could be considered to be an indication of lower purity of the sample solution. The lower limit of sample concentration for this assay was determined to be $5{\times}10^{-10}$ M to show uniform number of expected spots within 10% uncertainties in our experimental condition. An individual fluorescence intensity distribution for a mixture of isomers having doubly different emissivities was simulated by adding distributions obtained from Cy3 and nile red (NR) independently. The result indicated that the mixture could be identified from the pure compounds through the difference in the number of Gaussian functions to fit the distribution. This new assay technique can be applied to the purity test for synthetic biofluorophores which are usually prepared in small quantities not enough for classical ensemble assays.

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Estimation of the Number of Sources Based on Hypothesis Testing

  • Xiao, Manlin;Wei, Ping;Tai, Heng-Ming
    • Journal of Communications and Networks
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    • v.14 no.5
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    • pp.481-486
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    • 2012
  • Accurate and efficient estimation of the number of sources is critical for providing the parameter of targets in problems of array signal processing and blind source separation among other such problems. When conventional estimators work in unfavorable scenarios, e.g., at low signal-to-noise ratio (SNR), with a small number of snapshots, or for sources with a different strength, it is challenging to maintain good performance. In this paper, the detection limit of the minimum description length (MDL) estimator and the signal strength required for reliable detection are first discussed. Though a comparison, we analyze the reason that performances of classical estimators deteriorate completely in unfavorable scenarios. After discussing the limiting distribution of eigenvalues of the sample covariance matrix, we propose a new approach for estimating the number of sources which is based on a sequential hypothesis test. The new estimator performs better in unfavorable scenarios and is consistent in the traditional asymptotic sense. Finally, numerical evaluations indicate that the proposed estimator performs well when compared with other traditional estimators at low SNR and in the finite sample size case, especially when weak signals are superimposed on the strong signals.

Implementation of Elbow Method to improve the Gases Classification Performance based on the RBFN-NSG Algorithm

  • Jeon, Jin-Young;Choi, Jang-Sik;Byun, Hyung-Gi
    • Journal of Sensor Science and Technology
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    • v.25 no.6
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    • pp.431-434
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    • 2016
  • Currently, the radial basis function network (RBFN) and various other neural networks are employed to classify gases using chemical sensors arrays, and their performance is steadily improving. In particular, the identification performance of the RBFN algorithm is being improved by optimizing parameters such as the center, width, and weight, and improved algorithms such as the radial basis function network-stochastic gradient (RBFN-SG) and radial basis function network-normalized stochastic gradient (RBFN-NSG) have been announced. In this study, we optimized the number of centers, which is one of the parameters of the RBFN-NSG algorithm, and observed the change in the identification performance. For the experiment, repeated measurement data of 8 samples were used, and the elbow method was applied to determine the optimal number of centers for each sample of input data. The experiment was carried out in two cases(the only one center per sample and the optimal number of centers obtained by elbow method), and the experimental results were compared using the mean square error (MSE). From the results of the experiments, we observed that the case having an optimal number of centers, obtained using the elbow method, showed a better identification performance than that without any optimization.

Compressive Properties of 3D Printed TPU Samples with Various Infill Conditions (채우기 조건에 따른 3D 프린팅 TPU 샘플의 압축 특성)

  • Jung, Imjoo;Lee, Sunhee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.46 no.3
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    • pp.481-493
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    • 2022
  • This study investigated process conditions for 3D printing through manufacturing thermoplastic polyurethane (TPU) samples under different infill conditions. Samples were prepared using a fused deposition modeling 3D printer and TPU filament. 12 infill patterns were set (2D: grid, lines, zigzag; 3D: triangles, cubic, cubic subdivision, octet, quarter cubic; 3DF: concentric, cross 3D, cross, honeycomb), with 3 infill densities (20%, 50%, 80%). Morphology, actual time/weight and compressive properties were analyzed. In morphology: it was found that, as infill density increased, the increase rate of the number of units rose for 2D and fell for 3DF. Printing time varied with the number of nozzle movements. In the 3DF case, the number of nozzle movements increased rapidly with infill density. Sample weight increased similarly. However, where the increase rate of the number of units was low, sample weight was also low. In compressive properties: compressive stress increased with infill density and stress was high for the patterns with layers of the same shape.

A Study of Runoff Curve Number Estimation Using Land Cover Classified by Artificial Neural Networks (신경망기법으로 분류한 토지피복도의 CN값 산정 적용성 검토)

  • Kim, Hong-Tae;Shin, Hyun-Suk
    • Journal of Korea Water Resources Association
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    • v.36 no.4
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    • pp.633-645
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    • 2003
  • The techniques of GIS and remote sensing are being applied to hydrology, geomorphology and various field of studies are performed by many researcher, related those techniques. In this paper, curve number change detection is tested according to soil map and land cover in mountain area. Neural networks method is applied for land cover classification and GIS for curve number calculation. The first, sample area are selected and tested land cover classification, NN(84.1%) is superior to MLC(80.9%). So we selected NN with land cover classifier. The second, curve number from the land cover by neural network classifier(57) is compared with that(curve number) from the land cover by manual work(55). Two values are so similar. The third, curve number classified by NN in sample area was applied and tested to whole study area. As results of this study, it is shown that curve number is more exact and efficient by using NN and GIS technique than by (using) manual work.

Study on the Anti-cancer, Anti-metastasis and Immune Response Improvement of Aqua-acupuncture with Amomum Amarum Lourerio Infusion Solution (익지인약침(益智仁藥鍼)이 항암(抗癌) 및 면역기능(免疫機能)에 미치는 실험적(實驗的) 연구(硏究))

  • Park, Sang-Yong;Lee, Byung-Ryul
    • Journal of Acupuncture Research
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    • v.18 no.3
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    • pp.79-93
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    • 2001
  • Objective : This study was purposed to investigate the anti-cancer and anti-metastasis and immune response of Aqua-acupuncture with Amomum amarum Lourerio infusion solution. Methods : The Amomum amarum Lourerio infusion solution put into Chung-wan(CV12) of BALB/c or C57BL6 mice were rised to cancer by B15-F10 and HT1080, S-180 cancer cell line. Results : The following result have been obtained 1. The effect on expression of MMP-9 gene about the HT1080 cancer cell line was increased in 100, $50{\mu}g/m{\ell}$ diluent groups, compared with control group. 2. The effect on expression of MMP-9 gene about the B15-F10 cancer cell line was increased in all the sample groups, compared with control group. 3. S-180 cancer cell line transplants in BALB/c mice were inhibited significantly in weight inctease in all the sample groups, compared with control group. 4. The effect on spleen cell proliferation was decreased in all the sample groups, compared with control group. 5. The $IFN-{\gamma}$ in all the sample groups and the $TNF-{\alpha}$ in 25 and $12.5{\mu}g/m{\ell}$ diluent groups was increased. 6. In flow cytometry, the number of CD4+, CD19+ cell in all the sample group was increased and the number of CD8+ cell in $100{\mu}g/m{\ell}$ diluent group, compared with control group. Conclusion : According to the result, Aqua-acupuncture with Amomum amarum Lourerio infusion solution has significant anti-cancer, anti-metastasis and Immune response improvement.

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Effects of Heat Shock Treatment on Enzymatic Proteolysis for LC-MS/MS Quantitative Proteome Analysis

  • Arul, Albert-Baskar;Han, Na-Young;Jang, Young-Su;Kim, Hyojin;Kim, Hwan-Mook;Lee, Hookeun
    • Mass Spectrometry Letters
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    • v.7 no.1
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    • pp.1-11
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    • 2016
  • Various efforts have been developed to improve sample preparation steps, which strongly depend on hands-on processes for accurate and sensitive quantitative proteome analysis. In this study, we carried out heating the sample prior to trypsin digestion using an instrument to improve the tryptic digestion process. The heat shock generated by the system efficiently denatured proteins in the sample and increased the reproducibility in quantitative proteomics based on peptide abundance measurements. To demonstrate the effectiveness of the protocol, three cell lines (A human lung cancer cell line (A549), a human embryonic kidney cell line (HEK293T), and a human colorectal cancer cell line (HCT-116)) were selected and the effect of heat shock was compared to that of normal tryptic digestion processes. The tryptic digests were desalted and analysed by LC-MS/MS, the results showed 57 and 36% increase in the number of identified unique peptides and proteins, respectively, than conventional digestion. Heat shock treated samples showed higher numbers of shorter peptides and peptides with low inter-sample variation among triplicate runs. Quantitative LC-MS/MS analysis of heat shock treated sample yielded peptides with smaller relative error percentage for the triplicate run when the peak areas were compared. Exposure of heat-shock to proteomic samples prior to proteolysis in conventional digestion process can increase the digestion efficiency of trypsin resulting in production of increased number of peptides eventually leading to higher proteome coverage.