• Title, Summary, Keyword: 분산분석(ANOVA)

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Natural isotopes and trace element analyses in glass samples (판유리 시료에서 동위원소 및 미량원소 분석법)

  • Min, Ji-Sook;Heo, Sangcheol;Kim, Jae-Guin;Kim, Eun-Ho;Kim, Dong-Wook;Chung, Hee-Sun
    • Analytical Science and Technology
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    • v.20 no.3
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    • pp.219-226
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    • 2007
  • Glass is frequently encountered as types of materials that are submitted to forensic science laboratories as a result of trace evidence transfers. The repeatability and the reproducibility of trace element analysis were presented. An analysis of variance (ANOVA) was performed on laser ablation inductively coupled plasma spectrometric analyses of the fragments to identify the source. Pairwise comparisons were completed for all samples. In a pairwise comparison, each sample was compared to each other for a possible [n(n-1)/2] (n : numbers of the samples) total comparison to associate/discriminate samples using Tukey's HSD method. The aim of this study was to determine the utility of LA-ICP-MS for multi-element analysis of forensic samples. The 12 glass fragments from two manufacturers were collected and analyzed to identify the source. An analysis of variance (ANOVA) was performed on 31 elements in NIST 612 Trace elements in Glass. Elements were classified into four categories defined by the combination of precision and variation of inter-samples. We selected 11 elements, 209Bi, 90Zr, 121Sb, 178Hf, 59Co, 238U, 208Pb, 140Ce, 118Sn, 49Ti and 137Ba. 6 pairs out of 66 possible pairs were not distinguished when compared by 137Ba (p<0.05). However, all samples were distinguished using both 49Ti and 137Ba (p<0.05). In conclusion, multi-elemental analysis with LA-ICP-MS is a potential tecnique for the discrimination of forensic samples.

The Classification of Forest Types by Factor Analysis in Natural Forests of Dutasan (두타산 일대 천연림에서 요인분석에 의한 산림유형 분류)

  • Chung, Sang-Hoon;Kim, Ji-Hong
    • Journal of agriculture & life science
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    • v.46 no.4
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    • pp.21-30
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    • 2012
  • The objective of this study was to comprehend inter-species association and factors affecting species composition by factor analysis and to classify forest types of natural forests in Dootasan. We examined the correlation (positive or negative) of the major species by correlation analysis, the selection of three factors affecting the species composition by factor analysis, cluster analysis on the basis of factor scores, and the evaluation of the results of forest type classification by ANOVA. The outputs of correlation analysis were closely associated with those of factor analysis. The first factor affecting species composition was found to be the decline phenomenon of Pinus densiflora during forest succession process. The second and third factors were growth environments in valley and slope, respectively. The cluster analysis was carried out based on three factors affecting the species composition. The results indicated that the study area was classified into four forest types as follows: Quercus mogolica-Acer mono-Fraxinus rhynchophylla community, Q. mongolica community, Q. mongolica-Tilia amunrensis community and Pinus densiflora community. The dominant species of each community in the four classified forest types were significantly different (p<0.05).

Classification and Comparison of the Type of Graduates Job Mobility (대졸자의 일자리 이동 유형 분류 및 비교)

  • Chun, Young-Min;Lee, Seong-Jae
    • The Korean Journal of Applied Statistics
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    • v.23 no.2
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    • pp.235-247
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    • 2010
  • In this paper it is investigated how the number of work experiences is distributed among college graduates who have ever entered the labor market and built up career by turnover. To do so, we classified the type of work experience and, moreover, conduct ANOVA to explore wage differentials caused by the number of work experience and by the type of work experience, using the GOMS(graduates occupational mobility survey) from 2006 to 2007.

Analysis of Driver's Responsive Behavior to Variable Message Signs Using In-vehicle DGPS Data (VMS에 대한 운전자 반응특성 분석 (DGPS를 이용한 가속도 자료 분석을 중심으로))

  • Hong, Seung-Pyo;Park, Jun-Hyeong;O, Cheol;Jang, Myeong-Sun
    • Journal of Korean Society of Transportation
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    • v.25 no.6
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    • pp.111-120
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    • 2007
  • More accurate vehicle trajectory data are now readily available through Differential Global Positioning Systems (DGPS). A variety of research opportunities emerge with utilization of such high resolution traffic data. A novel approach of this study is to explore drivers' responsive behavior to variable message signs (VMS) by using individual vehicle trajectories extracted from in-vehicle DGPS data. Responsive characteristics of drivers traveling on urban freeways, which can be represented by speeds and acceleration rates, under the provision of real-time traffic information through VMS are statistically investigated. In addition to conducting an ANOVA test, probability density functions of acceleration rates were estimated. The findings of this study can be used to understand the impact of drivers' workload when providing VMS messages on traffic flow patterns. Furthermore, results can be important fundamentals to assist in conducting more realistic traffic simulations.

Analysis of Material Removal Rate of Glass in MR Polishing Using Multiple Regression Design (다중회귀분석을 이용한 BK7 글래스 MR Polishing 공정의 재료 제거 조건 분석)

  • Kim, Dong-Woo;Lee, Jung-Won;Cho, Myeong-Woo;Shin, Young-Jae
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.19 no.2
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    • pp.184-190
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    • 2010
  • Recently, the polishing process using magnetorheological fluids(MR fluids) has been focused as a new ultra-precision polishing technology for micro and optical parts such as aspheric lenses, etc. This method uses MR fluid as a polishing media which contains required micro abrasives. In the MR polishing process, the surface roughness and material removal rate of a workpiece are affected by the process parameters, such as the properties of used nonmagnetic abrasives(particle material, size, aspect ratio and density, etc.), rotating wheel speed, imposed magnetic flux density and feed rate, etc. The objective of this research is to predict MRR according to the polishing conditions based on the multiple regression analysis. Three polishing parameters such as wheel speed, feed rates and current value were optimized. For experimental works, an orthogonal array L27(313) was used based on DOE(Design of Experiments), and ANOVA(Analysis of Variance) was carried out. Finally, it was possible to recognize that the sequence of the factors affecting MRR correspond to feed rate, current and wheel speed, and to determine a combination of optimal polishing conditions.

A Statistical Study on Doorway Flow-time for Designing Doors of Ui LRT (우이-신설 경전철 출입문 설계를 위한 승하차시간 분석 연구)

  • Oh, Suk-Mun;Jang, Hyeon-Mog;Shin, Han-Chul
    • Journal of the Korean Society for Railway
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    • v.16 no.2
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    • pp.144-150
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    • 2013
  • This paper presents an analysis of door design for the Ui LRT based on experiments to predict doorway flow-time and their analyses results. A similar railway vehicle (from Gimhae LRT) and operational conditions are utilized to assess the doorway flow-time through repetitive experiments. Design of the experiments consists of four scenarios, and the experiments are repeated 39 times in total. We use the results of the experiments to verify the design of doors of Ui LRT (e.g. the required number of doors and their width). Various statistical analyses are carried out for the flow-time with respect to the number of boarding/alighting passengers. We make three category levels of boarding/alighting passengers, and analyze the mean and variance for each category, and then carry out One-Way ANOVA to analyze how the number of boarding/alighting and onboard passengers impact flow-time. The results of this paper can be used for making decisions about doors of the LRT vehicle.

Vegetation Classification using KOMPSAT-2 Imagery and High-resolution airborne imagery in Urban Area (KOMPSAT-2 영상 및 고해상도 항공영상을 이용한 도심지역 식생분류)

  • Park, Jeong Gi;Go, Shin Young;Cho, Gi Sung
    • Journal of Korean Society for Geospatial Information System
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    • v.21 no.4
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    • pp.21-27
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    • 2013
  • Recently, It is increasing that importance of systematic management by carbon sinks in forest resources. Especially, in terms of social, Forest resources in urban areas are important role as well as carbon sinks, and improvement of the natural environment of the city. In this study, through ANOVA analysis that a total of nine different vegetation index from rearranged NIR band of images to Forest tree species classified in urban areas using high-resolution aerial images and satellite images of KOMPSAT-2. And various vegetation indices such as NDVI are divided a species by forest units through statistical analysis. Also, separated species are compared to forest type map by the Forest Service. As a result, it is built as basis for vegetation management in urban areas.

Exploratory study on the relationship between supply chain performance and ICT capabilities (공급사슬성과와 정보기술역량 간의 관계에 관한 탐색적 분석)

  • Oh, Soojung;Oh, Kwangsik
    • Journal of the Korean Data and Information Science Society
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    • v.25 no.4
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    • pp.755-767
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    • 2014
  • Recently, many firms have introduced information and communication technology (ICT) into supply chain. However, existing studies have not yet insisted definite conclusion with respect to ICT impact on supply chain. Thus, this study subdivides supply chain performance which previous researchers have studied comprehensively while suggesting perspective of the use of firm's ICT capabilities. We classify ICT capabilities into four types of group and then analyze the difference between groups regarding each factor of supply chain performance by ANOVA analysis and Tukey method. As a result of analysis, the group in which all ICT capabilities are high shows the highest level of integration and flexibility performance among supply chain performances. On the other hand, the group in which all ICT capabilities are low presents the lowest level of integration and flexibility performance. We also provide more precise and specific information with practitioners by analyzing the difference between groups with regard to detailed measurements on integration and flexibility variables.

Optimal Grinding Condition Using the Design of Experiments (실험계획법을 이용한 최적연삭조건)

  • 이대욱;오창진;김성청;김옥현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.866-869
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    • 2000
  • To improve quality of the ground surface, we have to consider a number of parameters. But it is difficult to make experiment with many parameters. Most of all experiments try to search optimal grinding condition with conservative factors such as feed rate, depth of cut, wheel rotating speed, etc. But This paper attempts to view the significance of some different factors effecting on the surface roughness by introducing helical scan grinding method and material removal rate. The design of experiment is used to find the optimal grinding condition which minimizes the surface roughness value bout optical glass material. To analyze experimental results, ANOVA(ANalysis of VAriation) is used. Discussion on the result about helical scan grinding is also given.

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Pridiction of chip breakability by an orthogonal array method (직교배열법에 의한 칩절단특성 예측)

  • 이영문;양승한;권오진
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1008-1011
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    • 2001
  • The purpose of this paper is to evaluate the chip breakability during turning using the experimental equation, which is developed by an orthogonal array method. The chip breaking index(CB), non-dimensional parameter is used in the evaluation of chip breakability. The analysis of variance(ANOVA)-test has been used to check the significance of cutting parameters. And using the result of ANOVA-test, the experimental equation of chip breakability, which consists of significant cutting parameters, has been developed.

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