• Title/Summary/Keyword: Higher-order statistics

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A Visualization of Traffic Accidents Hotspot along the Road Network (도로 네트워크를 따른 교통사고 핫스팟의 시각화)

  • Cho, Nahye;Jun, Chulmin;Kang, Youngok
    • Journal of Cadastre & Land InformatiX
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    • v.48 no.1
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    • pp.201-213
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    • 2018
  • In recent years, the number of traffic accidents caused by car accidents has been decreasing steadily due to traffic accident prevention activities in Korea. However, the number of accidents in Seoul is higher than that of other regions. Various studies have been conducted to prevent traffic accidents, which are human disasters. In particular, previous studies have performed the spatial analysis of traffic accidents by counting the number of traffic accidents by administrative districts or by estimating the density through kernel density method in order to identify the traffic accident cluster areas. However, since traffic accidents take place along the road, it would be more meaningful to investigate them concentrated on the road network. In this study, traffic accidents were assigned to the nearest road network in two ways and analyzed by hotspot analysis using Getis-Ord Gi* statistics. One of them was investigated with a fixed road link of 10m unit, and the other by computing the average traffic accidents per unit length per road section. As a result by the first method, it was possible to identify the specific road sections where traffic accidents are concentrated. On the other hand, the results by the second method showed that the traffic accident concentrated areas are extensible depending on the characteristic of the road links. The methods proposed here provide different approaches for visualizing the traffic accidents and thus, make it possible to identify those sections clearly that need improvement as for the traffic environment.

Meta-analysis on Methane Mitigating Properties of Saponin-rich Sources in the Rumen: Influence of Addition Levels and Plant Sources

  • Jayanegara, Anuraga;Wina, Elizabeth;Takahashi, Junichi
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.10
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    • pp.1426-1435
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    • 2014
  • Saponins have been considered as promising natural substances for mitigating methane emissions from ruminants. However, studies reported that addition of saponin-rich sources often arrived at contrasting results, i.e. either it decreased methane or it did not. The aim of the present study was to assess ruminal methane emissions through a meta-analytical approach of integrating related studies from published papers which described various levels of different saponin-rich sources being added to ruminant feed. A database was constructed from published literature reporting the addition of saponin-rich sources at various levels and then monitoring ruminal methane emissions in vitro. Accordingly, levels of saponin-rich source additions as well as different saponin sources were specified in the database. Apart from methane, other related rumen fermentation parameters were also included in the database, i.e. organic matter digestibility, gas production, pH, ammonia concentration, short-chain fatty acid profiles and protozoal count. A total of 23 studies comprised of 89 data points met the inclusion criteria. The data obtained were subsequently subjected to a statistical meta-analysis based on mixed model methodology. Accordingly, different studies were treated as random effects whereas levels of saponin-rich source additions or different saponin sources were considered as fixed effects. Model statistics used were p-value and root mean square error. Results showed that an addition of increasing levels of a saponin-rich source decreased methane emission per unit of substrate incubated as well as per unit of total gas produced (p<0.05). There was a decrease in acetate proportion (linear pattern; p<0.001) and an increase in propionate proportion (linear pattern; p<0.001) with increasing levels of saponin. Log protozoal count decreased (p<0.05) at higher saponin levels. Comparing between different saponin-rich sources, all saponin sources, i.e. quillaja, tea and yucca saponins produced less methane per unit of total gas than that of control (p<0.05). Although numerically the order of effectiveness of saponin-rich sources in mitigating methane was yucca>tea>quillaja, statistically they did not differ each other. It can be concluded that methane mitigating properties of saponins in the rumen are level- and source-dependent.

The actual type of domestic safety accident of children and the safety knowledge according to variables of parents (가정내 유아의 안전사고 유형과 부모의 변인에 따른 안전지식)

  • Kim, Ji-Young;Kim, Na-Rim
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.454-461
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    • 2017
  • The purpose of this study is to investigate the types of domestic safety accidents involving children and to verify the difference of safety knowledge according to variables of parents. Subjects include 226 parents who have 3-5 year old infants enrolled in kindergartens and day care centers in I-city, Jeollabuk-do. The study tools are modified and complemented questionnaire for the study purpose referred to the preceding research data and the literature. For the processing of collected data, frequency analysis, descriptive statistics, one-way ANOVA, and the Duncan post-test were utilized using the SPSS program. The results of this study are as follows: First, safety accidents occurred at the majority of homes which have infant children. On average, the occurrence frequency was 1.78 times per six months. The accidents involving infants occurred in the order of drop or slip, crash or impact, stricture or jamming, fall, stab or cut, burn, swallow or inhalation. Second, both parents had an average level of safety knowledge. There was a distinction in the areas of 'fall' and 'first aid' according the mother's age. In addition, stay-at-home mothers had the higher level of safety knowledge compared with working mothers in the areas of 'general safety knowledge' and 'fire'. There was a distinction in the area of 'fire' according to the father's age. Given these findings, safety training programs for parents to improve safety knowledge needs to be developed.

A Study of Surface Electromyography Measurement of Wrist Exercise (Extension, Flexion, Grasping) in Healthy People (정상인의 완관절 신전, 굴곡, 악력(握力) 시 표면근전도 측정 연구)

  • Kim, Seok Hee;Lee, Kyung Jin;Choi, Yoo Min;Kim, Ju Yong;Yook, Tae Han;Lee, Sang Lyoung;Kim, Jong Uk
    • Journal of Acupuncture Research
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    • v.32 no.3
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    • pp.53-60
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    • 2015
  • Purpose : This study aimed to prove that surface electromyography(SEMG) can be used to identify the degree of symptoms of diseases in the upper extremities; it also aimed to confirm various potential therapeutic effects through an inquiry into the value measured by the SEMG on certain acupuncture points in the upper extremities. Methods : Fifty healthy people received instructions for the method of exercise: wrist flexion, extension and hand grasping. Disposable electrodes were attached to acupuncture points of Susamni($LI_{10}$), Naegwan($PC_6$), Oegwan($TE_5$) and below Sohae($HT_3$) two cun on both sides in flexion, extension and grasping to measure the SEMG values. The research results were analyzed using SPSS statistics Ver. 22.0(IBM, USA). Results : The average value was highest on Naegwan($PC_6$) in grasping, and the average SEMG value was higher in the order of grasping, extension and flexion. The asymmetry index of each point was Susamni($LI_{10}$) $16.26{\pm}13.59%$, Oegwan($TE_5$) $20.38{\pm}15.59%$, below Sohae($HT_3$) two cun $20.89{\pm}16.77%$, Naegwan($PC_6$) $22.49{\pm}14.91%$ in wrist extension, Susamni($LI_{10}$) $25.99{\pm}21.44%$, Oegwan($TE_5$) $21.15{\pm}15.94%$, below Sohae($HT_3$) two cun $19.62{\pm}15.46%$, Naegwan($PC_6$) $19.93{\pm}16.85%$ in wrist flexion, Susamni($LI_{10}$) $16.60{\pm}12.21%$, Oegwan($TE_5$) $10.94{\pm}8.29%$, below Sohae($HT_3$) two cun $15.20{\pm}12.60%$, Naegwan($PC_6$) $11.68{\pm}7.77%$ in grasping. Conclusions : In this study, to identify the degree of symptoms of diseases in the upper extremities and confirm therapeutic effects, it is necessary to analyze the calculated percentage and compare the SEMG measurement of special points with those of other points, and with the asymmetry index.

The Relationship between Personality Type, Self-Efficacy, Resilience and Workplace Bullying Experience in General Hospital Nurses (일 종합병원 간호사의 성격유형, 자기효능감, 회복 탄력성, 직장 내 괴롭힘 피해 경험의 관계)

  • Cho, Ae young
    • Journal of Internet of Things and Convergence
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    • v.5 no.1
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    • pp.13-28
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    • 2019
  • The purpose of this study is to identify degree of the personality type, resilience, self-efficacy, and workplace bullying Experience among nurses at General Hospital, to ascertain the correlation between them and to ascertain factors that may affect workplace bullying. This study collected data from October 22, 2018 to October 26, 2018 through structured questionnaires from 260 nurses working at General Hospital in Seoul City, and the collected data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression analysis using SPSS / WIN 21.0. Analysis of differences in general characteristics showed that workplace bullying was significantly different according to witness of bullying, workplace satisfaction. Resilience was significantly different according to marital status, religion, final education, and workplace satisfaction. And self-efficacy was found to be different according to respondents' marital status, religion. The relationship between DISC personality type, workplace bullying, resilience and self-efficacy showed that workplace bullying had a negative correlation with resilience, and resilience showed a positive correlation with self-efficacy. As a result of the multiple regression analysis in order to identify the factors that, workplace satisfaction, witness of workplace bullying and the resilience was the factor affecting workplace bullying; workplace bullying was decreased as the resilience was higher.

The Mean-VaR Framework and the Optimal Portfolio Choice (평균-VaR 기준과 최적 포트폴리오 선택)

  • Ku, Bon-Il;Eom, Young-Ho;Choo, Youn-Wook
    • The Korean Journal of Financial Management
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    • v.26 no.1
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    • pp.165-188
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    • 2009
  • This paper has suggested the methodology for the frontier portfolios and the optimal portfolio under the mean-VaR framework, not assuming the normal distribution and considering the investor's preferences for the higher moments of return distributions. It suggested the grid and rank approach which did not need an assumption about return distributions to find the frontier portfolios. And the optimal portfolio was selected using the utility function that considered the 3rd and the 4th moments. For the application of the methodology, weekly returns of the developed countries index, the emerging market index and the KOSPI index were used. After the frontier portfolios of the mean-variance framework and the mean-VaR framework were selected, the optimal portfolios of each framework were compared. This application compared not only the difference of the standard deviation but also the difference of the utility level and the certainty equivalent expressed by weekly expected returns. In order to verify statistical significances about the differences between the mean-VaR and the mean-variance, this paper presented the statistics which were obtained by the historical simulation method using the bootstrapping. The results showed that an investor under the mean-VaR framework had a tendency to select the optimal portfolio which has bigger standard deviation, comparing to an investor under the mean-variance framework. In addition, the more risk averse an investor is, the bigger utility level and certainty equivalent he achieves under the mean-VaR framework. However, the difference between the two frameworks were not significant in statistical as well as economic criterion.

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Effects of Knowledge-based Startups on Employment Growth (지식기반산업 창업기업의 고용창출 효과)

  • Lee, Jeong Hyun;Lee, Hee Yeon
    • Journal of the Economic Geographical Society of Korea
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    • v.20 no.2
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    • pp.137-157
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    • 2017
  • As unemployment rises and economic growth slows, interest in startups, which is considered to be the driving force of job creation, is increasing. This study aimed to analyze the employment effects of knowledge-based startups in South Korea. In particular, startups were divided into three categories (knowledge-based manufacturing, knowledge-based service, and other industries) and the region were divided into the capital region and the other regions. The result of the analysis, which used census on Establishments Data from Statistics Korea(KOSIS), showed that the employment effects of startups change in three steps over time. When new firms were created, employment increases instantly. However, as the competition among firms increases, some firms exit the market and employment decreases. In the long-term, some firms will survive the market competition and increase their firm size and the number of jobs they offer. The total employment effect was greater for knowledge-based startups than the other industries startups. The total employment effect of knowledge-based startups are 2.84%p for the period of 6 years. Startups in the Capital region showed higher employment effect than startups in other regions. This implies that in the capital region, employment increases more after the startups are created, but due to fierce competition, employment also decreases relatively more than it does in other regions. However, companies that survive competition create more employment. This study may give some policy implications that startup policies should be tailored to the startup's type and regional characteristics in order to achieve more effective job creation performance.

Intervention for Reducing Dental Fear and Anxiety of Dental Patients (치과내원 환자의 치과공포 감소를 위한 중재법 적용)

  • Shin, Sun-Jung;Shin, Bo-Mi;Koh, Boo-Il;Bae, Soo-Myoung
    • Journal of dental hygiene science
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    • v.15 no.3
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    • pp.369-376
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    • 2015
  • The purposes of this study were to assess dental fear and anxiety level of patients attending a dental clinic using the dental fear survey (DFS) scale, to apply interventions chosen by patients for reducing dental fear and anxiety and measure their effects. This study surveyed 34 patients who visited a dental clinic in Seoul about their self-rated health and their experience of dental fear, and measured the level of dental fear using DFS. Trained dental hygienists applied interventions desired by the patients for reducing dental fear and anxiety and, for each intervention, examined the patients' satisfaction (very helpful [5 point]~not helpful at all [1 point]). Collected data were analyzed using IBM SPSS Statistics ver. 21.0 through independent t-test or one-way ANOVA for difference in level of fear according to related characteristics, and through Wilcoxon signed rank test for comparison between before and after the intervention. The subjects' mean level of fear (DFS score) was 44.53, which was an average level, and the level of dental fear was relatively high for stimulus-response (2.72). The level of dental fear was higher in those who had experienced pains or indirect dental fear from dental treatment in the past, and those whose subjectively perceived health state was poor (p<0.05). With regard to the applied dental fear intervention, 'Helpful (3.57)' was the most common answer. Overall satisfaction before and after the application of dental fear intervention was generally high as 4.37 and 4.35, respectively, but it decreased slightly after the intervention. In order to lower the level of dental fear, it is considered effective to survey not only the level of dental fear but also patients' need of dental fear interventions and to apply a suitable intervention. It is also required to educate dental workers and to develop related manuals.

Influence of Self-esteem and Consumer Socialization Agents on Rational Consumption Behavior of Middle School Students (중학생의 자아존중감과 소비자사회화 영향요인이 합리적 소비행동에 미치는 영향)

  • Lee, Seung Jin;Yu, Nan Sook
    • Journal of Korean Home Economics Education Association
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    • v.31 no.4
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    • pp.115-128
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    • 2019
  • The purpose of this study was to examine the influence of self-esteem and consumer socialization agents on rational consumption patterns of middle school students. Using a convenient sampling method, the data were collected from middle schools in Seoul, Gyeonggi, Chungcheong, Jeonnam, and Gwangju and a total of 412 copies were analyzed. The descriptive statistics, Chronbach's α, t-test, and stepwise regression analysis were performed using the SPSS and the results were as follows. First, rational consumption behavior was 3.18 and self-esteem was 3.54 on a 5-Likert scale. As for consumer socialization agents, parents was the highest at 3.13, followed by school 2.83, mass media 2.78 and peers 2.73. Second, the average comparison of rational consumption behavior and consumer socialization agents by gender showed that there was no gender difference in rational consumption behavior, but in the case of consumer socialization, girls were higher than boys. Third, examining the influence of self-esteem and consumer socialization agents on rational consumption behavior, it was found that the amount of money, mass media, and peers showed an negative effects on rational consumption behavior, while self-esteem and parents showed positive effects on rational consumption behavior. In this regard, middle school students need to have more self-esteem and guide their peers so that their influence can be positive in the home economics class in order to become consumers with rational consumption behavior.

Central Technology Deriving for the Patents of Medical Device using Social Network Analysis (특허 네트워크 분석을 활용한 의료기기 분야에서의 핵심기술 도출)

  • Chun, Jae-Heon;Lee, Chang-Seop;Lee, Suk-Jun
    • Management & Information Systems Review
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    • v.35 no.2
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    • pp.221-254
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    • 2016
  • With increasing interest of health due to population aging, medical device industry is highlighted as a promising industry. However, Korea medical device industry is not enough market competitiveness compared to global company due to a narrow domestic market and a small company structure. In order to retain the national competitiveness, it is necessary that we have to derive a central technology and its trend. This study has predicted a central technology for medical device industrial using patent network analysis. The central technology is defined as a key technology that is connected to most other technologies and that significantly affects them. For the empirical study, we conducted social network analysis using covariance and correlation coefficient between IPC codes extracted from medical device patents, introduced by Jun(2012). A social network is a social structure of diverse items as well as of human beings. In this study, we set each medical device as a node in an SNA and analyze the Degree values between them. Also, Korea health industrial statistics system are utilized for verification of selected central technology. As a result, we found that the central technology is located on the medical device items, which are listed higher the amount of production. The central technology selected through the proposed methodology will provide a inspiration for establishment of R&D policy.

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