• Title/Summary/Keyword: Outliers

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A research on the Relationship between the Socio-economic Factors of the Regions and Suicidal Ideation of the Elderly -By utilizing the multi-level analyses- (지역의 사회·경제적 요인과 노인의 자살생각 간의 관련성 연구 -다수준 분석을 활용하여-)

  • Choi, Kwang-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.584-594
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    • 2016
  • This research empirically analyzes, from an ecological perspective, whether socio-economic factors of the regions in which the elderly live have any actual influence on thoughts of suicide on the part of the elderly. Microscopic data either included outliers in part of the variables, including income and other variables of that type, from among source data from investigations into actual conditions of the elderly in 2014. Regarding macroscopic data, the indices that represent social and economic situations in each region, which were provided by KOSIS, were selected. Regarding the method of analysis, hierarchical or multi-level analysis models were applied by considering special hierarchical characteristics and heterogeneity at the personal and regional levels. The analyses showed that the following had statistically significant influences: 1. the cost-of-living index and the national basic supply and demand rate of the region; 2. the extent of natural disaster damage; and 3. the number of leisure and welfare facilities for the elderly, compared to the elderly population. Based on the results, proposals are made for systematic and practical endeavors in the community.

Methodology for Estimation of Link Travel Time using Density-based Disaggregated Approach (밀도기반 비집계 접근법을 이용한 구간통행시간 추정 방법론)

  • Chang, Hyunho;Lee, Soong-bong;Han, Donghee;Lee, Young-Ihn
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.16 no.5
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    • pp.134-143
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    • 2017
  • In the case of highway, there may be a large number of travel time groups when there are a bus exclusive lane, a rest area, a sleeping shelter, etc. in the corresponding section. In most of the conventional travel time estimation studies, one representative travel time (assuming normal distribution) group is assumed in the low sample collection state, and if it is out of the specified range, it is determined as outliers and then the travel time is estimated. However, if there is a bus exclusive lane, a rest area, or a sleeping shelter in the relevant section, such as the highway, the distribution of travel time will be in the form of a bi-modal or a multi-modal, rather than a regular distribution. Therefore, applying the existing estimation methodology may result in distorted results. To solve this problem, first, it should be reliable even in the case of insufficient number of samples. Second, we propose a methodology to select the representative time group among a number of time groups and to estimate the representative time using individual time data of the selected time group.

Compatibility of MODIS Vegetation Indices and Their Sensitivity to Sensor Geometry (MODIS 식생지수에 미치는 센서 geometry의 영향과 센서 간 자료 호환성 검토)

  • Park, Sunyurp
    • Journal of the Korean Geographical Society
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    • v.49 no.1
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    • pp.45-56
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    • 2014
  • Data composite methods have been typically applied to satellite-based vegetation index(VI) data to continuously acquire vegetation greenness over the land surface. Data composites are useful for construction of long-term archives of vegetation indices by minimizing missing data or contamination from noise. In addition, if multi-sensor vegetation indices that are acquired during the same composite periods are used interchangeably, data stability and continuity may be significantly enhanced. This study evaluated the influences of sensor geometry on MODIS vegetation indices and investigated data compatibility of two difference vegetation indices, the Normalized Difference Vegetation Index(NDVI) and the Enhanced Vegetation Index(EVI), for potential improvement of long-term data construction. Relationships between NDVI and EVI turned out statistically significant with variations among vegetation covers. Due to their curvilinear relationships, NDVI became saturated and leveled off as EVI reached high ranges. Correlation coefficients between Terra- and Aqua-based vegetation indices ranged from 0.747 to 0.963 for EVI, and from 0.641 to 0.880 for NDVI, showing better compatibility for EVI compared to NDVI. In-depth analyses of VI outliers that deviated from regression equations constructed from the two different sensors remain as a future study to improve their compatibility.

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Comparative analysis of official demographics (공식인구통계들에 대한 비교 분석)

  • 김종태
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.1
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    • pp.99-108
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    • 2017
  • There are three official official demographics of the Republic of Korea: the population census, population projections, and resident population. Among these, the population projections estimates are based on population census statistics, which are conducted every five years. This study compared and analyzed the future population statistics and resident population statistics. In order to detect errors in the census process, we surveyed the outliers of demographic data. Based on these, we aimed to verify the reliability of official demographics. Resident registration demographics showed a tendency to increase as the age increased from 0 to 12 years, although the population had to decrease as the age increased. In the population projections, as the age increases from 18 to 28, a new population has developed and the population has increased. Also, in the resident population, between 2009 and 2010, in the population projections, between 2010 and 2011, there was a strange phenomenon that the population grew as a result of a new population as the age of all ages increased. Both official demographics need to be carried out through more accurate verification. Increasing the reliability of the aged population survey on the elderly population statistics will provide greater efficiency in establishing administrative policies.

Rethinking Theoretical and Practical Issues of Economic Valuation of Library Services (도서관 서비스의 경제적 가치 측정의 이론적, 실제적 검토)

  • Shim, Won-Sik
    • Journal of the Korean Society for Library and Information Science
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    • v.44 no.4
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    • pp.231-247
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    • 2010
  • This research examines a number of theoretical and practical issues when measuring the economic value of library services. In particular, using two recent studies conducted in Korea as illustrations, the study shows how various measurement decisions affect the final outcomes in the economic valuation of library services and thus points to the need for a more reliable study design. Specific areas of measurement discussed include the following: scope of measurement, application of CVM(Contingent Valuation Method), time vs. monetary value measurement, dealing with outliers, allowing alternatives, and the use of estimation. ROI(Return on Investment) scores or benefit cost ratios vary significantly according to different measurement choices even in the same study. There is a need for collecting qualitative data that complements the quantitative data typically collected in economic valuation studies. The outcome of economic valuation of library services should be considered as one of many representations of library values. Practitioners and researchers should exercise caution in interpreting those results but be able to leverage them to better communicate the value of library services.

A Variant of Improved Robust Fuzzy PCA (잡음 민감성이 개선된 변형 퍼지 주성분 분석 기법)

  • Kim, Seong-Hoon;Heo, Gyeong-Yong;Woo, Young-Woon
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.2
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    • pp.25-31
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    • 2011
  • Principal component analysis (PCA) is a well-known method for dimensionality reduction and feature extraction. Although PCA has been applied in many areas successfully, it is sensitive to outliers due to the use of sum-square-error. Several variants of PCA have been proposed to resolve the noise sensitivity and, among the variants, improved robust fuzzy PCA (RF-PCA2) demonstrated promising results. RF-PCA2, however, still can fall into a local optimum due to equal initial membership values for all data points. Another reason comes from the fact that RF-PCA2 is based on sum-square-error although fuzzy memberships are incorporated. In this paper, a variant of RF-PCA2 called RF-PCA3 is proposed. The proposed algorithm is based on the objective function of RF-PCA2. RF-PCA3 augments RF-PCA2 with the objective function of PCA and initial membership calculation using data distribution, which make RF-PCA3 to have more chance to converge on a better solution than that of RF-PCA2. RF-PCA3 outperforms RF-PCA2, which is demonstrated by experimental results.

A Spatial Statistical Approach to Residential Differentiation (II): Exploratory Spatial Data Analysis Using a Local Spatial Separation Measure (거주지 분화에 대한 공간통계학적 접근 (II): 국지적 공간 분리성 측도를 이용한 탐색적 공간데이터 분석)

  • Lee, Sang-Il
    • Journal of the Korean Geographical Society
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    • v.43 no.1
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    • pp.134-153
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    • 2008
  • The main purpose of the research is to illustrate the value of the spatial statistical approach to residential differentiation by providing a framework for exploratory spatial data analysis (ESDA) using a local spatial separation measure. ESDA aims, by utilizing a variety of statistical and cartographic visualization techniques, at seeking to detect patterns, to formulate hypotheses, and to assess statistical models for spatial data. The research is driven by a realization that ESDA based on local statistics has a great potential for substantive research. The main results are as follows. First, a local spatial separation measure is correspondingly derived from its global counterpart. Second, a set of significance testing methods based on both total and conditional randomization assumptions is provided for the local measure. Third, two mapping techniques, a 'spatial separation scatterplot map' and a 'spatial separation anomaly map', are devised for ESDA utilizing the local measure and the related significance tests. Fourth, a case study of residential differentiation between the highly educated and the least educated in major Korean metropolitan cities shows that the proposed ESDA techniques are beneficial in identifying bivariate spatial clusters and spatial outliers.

Genetic Parameter Estimation in Seedstock Swine Population for Growth Performances

  • Choi, Jae Gwan;Cho, Chung Il;Choi, Im Soo;Lee, Seung Soo;Choi, Tae Jeong;Cho, Kwang Hyun;Park, Byoung Ho;Choy, Yun Ho
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.4
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    • pp.470-475
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    • 2013
  • The objective of this study was to estimate genetic parameters that are to be used for across-herd genetic evaluations of seed stock pigs at GGP level. Performance data with pedigree information collected from swine breeder farms in Korea were provided by Korea Animal Improvement Association (AIAK). Performance data were composed of final body weights at test days and ultrasound measures of back fat thickness (BF), rib eye area (EMA) and retail cut percentage (RCP). Breeds of swine tested were Landrace, Yorkshire and Duroc. Days to 90 kg body weight (DAYS90) were estimated with linear function of age and ADG calculated from body weights at test days. Ultrasound measures were taken with A-mode ultrasound scanners by trained technicians. Number of performance records after censoring outliers and keeping records pigs only born from year 2000 were of 78,068 Duroc pigs, 101,821 Landrace pigs and 281,421 Yorkshire pigs. Models included contemporary groups defined by the same herd and the same seasons of births of the same year, which was regarded as fixed along with the effect of sex for all traits and body weight at test day as a linear covariate for ultrasound measures. REML estimation was processed with REMLF90 program. Heritability estimates were 0.40, 0.32, 0.21 0.39 for DAYS90, ADG, BF, EMA, RCP, respectively for Duroc population. Respective heritability estimates for Landrace population were 0.43, 0.41, 0.22, and 0.43 and for Yorkshire population were 0.36, 0.38, 0.22, and 0.42. Genetic correlation coefficients of DAYS90 with BF, EMA, or RCP were estimated to be 0.00 to 0.09, -0.15 to -0.25, 0.22 to 0.28, respectively for three breeds populations. Genetic correlation coefficients estimated between BF and EMA was -0.33 to -0.39. Genetic correlation coefficient estimated between BF and RCP was high and negative (-0.78 to -0.85) but the environmental correlation coefficients between these two traits was medium and negative (near -0.35), which describes a highly correlated genetic response to selection on one or the other of these traits. Genetic Trends of all three breeds tend to be towards bigger EMA or greater RCP and shorter DAYS90 especially from generations born after year 2000.

A Study on the Factors Influencing Crowdfunding by Shared Value and Communication (가치공유와 커뮤니케이션이 크라우드펀딩 참여의도에 미치는 영향에 관한 연구)

  • Yu, Yun-hyeong;Choi, Myung-gil
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.5
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    • pp.113-127
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    • 2020
  • Based on the social exchange theory and innovation diffusion theory, this study is to identify the correlation between factors influencing investor's funding intention in crowdfunding and to analyze moderating effect of trust in the relationship of shared value, communication and individual innovation. The purpose of this study is to consider the funding trends of crowdfunding investors from a personal point of view through the results of the study and to help fundraiser of crowdfunding establish specifically strategies for financing. In order to conduct empirical analysis, an online survey was conducted on people who had participated in crowdfunding, and a total of 228 questionnaires were collected and a total of 186 responses were finally analyzed, excluding outliers. For data analysis, structural equation model analysis was conducted using SPSS 26.0 and Smart PLS 3.0. The results of this study showed that shared value in the relationship between fundraiser and investors has a significant effect on the perceived risk. High level of communication between fundraiser and investors showed positive effects on the level of commitment of the crowdfunding project and the innovation of the individual investor. And commitment had a positive effect on the funding intention. According to the results of this research, trust has moderating effect only in relationship between shared value and perceived risk. It is significant that investors share the value of fundraiser together is a motivation factor to fund in crowdfunding and an opportunity to recognize the risk. Through this study, it is expected to utilize them in establishing strategies for start-ups and marketing plans to raise funds through crowdfunding and to empirically identify factors influencing the funding intention through individual levels of crowdfunding investors.

The Application State of the Sunnybrook Facial Grading System for Facial Palsy Patients : A retrospective study (안면마비 환자에 대한 Sunnybrook Facial Grading System의 적용 실태 분석 : 후향적 관찰연구)

  • Han, Ji Sun;Kwon, Min Soo;Kim, Jung Hwan;Jo, Dae Hyun;Jo, Hee Jin;Choi, Ji Eun;Kim, Ji Hye;Kim, Hyun Ho;Lee, Sang Hoon;Park, Young Jae;Park, Young Bae
    • Journal of Acupuncture Research
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    • v.33 no.4
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    • pp.101-108
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    • 2016
  • Objectives : Among the assessment tools for evaluating facial function, the House-Brackmann scale is used as a standard tool, but it has some shortcomings. The Sunnybrook Facial Grading System can assess the after effects of facial palsy and facial movement by each part of the face. By understanding the application state of this Sunnybrook Facial Grading System, we intend to analyze the relationship between House-Brackmann scale score and Sunnybrook Facial Grading System score so that we can examine the advantages of the Sunnybrook Facial Grading System as a more accurate tool. Methods : We screened both inpatients and outpatients who visited the Facial Palsy Center at Kyung Hee University Hospital for Korean medical treatment and were evaluated with the Sunnybrook Facial Grading System from December 2015 to October 2016. A total of 159 out of 166 patients were studied, including basic characteristics and missing data. We used descriptive statistics for general features of patients and SPSS Ver.18 for statistical analysis. Results : House-Brackmann scale and Sunnybrook Facial Grading System have high negative correlation through Pearson Correlation Coefficient with a score of -0.884. Analyzing outlier data resulting from relation analysis between the House-Brackmann scale and the Sunnybrook Facial Grading System showed many outliers when the damaged state of each part of the face is different. Conclusion : Sunnybrook Facial Grading System can make up for faults of the House-Brackmann scale, which is inferior in accuracy when each damage status of each part of the face is different. Sunnybrook Facial Grading System performs a detailed assessment of facial function and sequelae of facial palsy easier than the House-Brackmann scale.