• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.767-769
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• 2003

컴퓨터와 무선 통신 기술의 발달로 인하여 LBS(Location based Service)와 같은 새로운 이동체 관련 서비스가 생겨나고 있다. 이와 같은 서비스들은 이동체들이 일정 주기를 가지고 자신의 정보를 서버로 전송하는데 이는 많은 디스크 입출력을 요구하게 된다. 그러므로 이동체 데이터에 대하여 다중 디스크를 이용한 병렬 입출력이 요구되고 있다. 그러나 기존의 디클러스터링 방법은 시간 도메인을 고려하지 않거나 공간 관련성만을 고려하여 디클러스터링을 하므로, 하나의 디스크에 특정 이동체의 궤적이 집중 되는 문제점이 있다. 이 문제점은 디스크의 병목현상으로 인한 느린 응답시간과 낮은 처리율의 결과를 발생시킨다. 그러므로 이동 객체의 빠른 질의 처리를 위한 새로운 디클러스터링 기법이 필요하다. 이 논문에서는 다중 디스크 기반의 시스템에서 이동 객체에 대한 영역질의시 빠른 응답시간과 높은 처리율물 얻기 위하여 새로운 디클러스터링 기법을 제시한다. 이동체 데이터의 궤적 MBB중 공간 좌표로부터 Predefined Disk를 생성하고 PDT-Proximity를 이용하여 시간 도메인을 고려하는 방법이다. 위와 같이 이동 객체의 특성을 고려한 새로운 디클러스터링 방법으로 시스템의 성능을 향상시킬 수 있다.

• Journal of the Korean housing association
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• v.25 no.5
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• pp.73-82
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• 2014

The purpose of this study is to identify U.S. Baby Boomers' intention to move and their reasons for moving after retirement, and to examine the associations between their socio-demographic characteristics and housing characteristics, and their reasons for moving after retirement factors. A total of 403 usable data were collected through an online survey using a self-administrated questionnaire. For data analyses, descriptive statistics, factor analysis, t-test, and ANOVA were used. Almost 30% of the total respondents considered moving and 15% were strongly agreed to move after their retirement. The most frequently mentioned reasons for moving after retirement were 'a place with good weather', 'being close to leisure activities', and 'a change or decline of my current neighborhood'. Four factors of reasons for moving after retirement (quality of residential environment, need assistant, proximity to activities, and proximity to family/friends) were identified. Age, marital status, number of household, housing type, homeownership, length of residence, and number of bedroom were significantly associated with the four factors of reasons for moving. The results of this study provide a better understanding to U.S. Baby Boomers' housing behavior after retirement which is 10 years faster than Korea, and suggest insights of housing plan for Korean older adults.

• Asian Journal of Atmospheric Environment
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• v.7 no.1
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• pp.56-63
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• 2013

Children are particularly vulnerable to adverse health effects associated with heavy metal exposure. The goal of this study was to investigate the relationship between proximity to an industry complex and blood lead and urinary cadmium levels for children aged 7-13 who lived in Ulsan where a big petrochemical complex is located. We conducted a questionnaire survey to collect data including sociodemographics, daily habits, residential environment, etc. We also analyzed blood lead and urinary cadmium levels using Atomic Absorption Spectrometry (AAS). Data were analyzed using regression analysis. All statistical analyses were conducted with SAS software version 9.2. We calculated distance by using a Geographic Information System (ArcGIS version 10.0). The geometric mean blood lead level was 1.55 ${\mu}g/dL$ (boys: 1.59 ${\mu}g/dL$, girls: 1.51 ${\mu}g/dL$), and the geometric mean urinary cadmium level was 0.51 ${\mu}g/g$ creatinine (boys: 0.45 ${\mu}g/g$ creatinine, girls: 0.58 ${\mu}g/g$ creatinine). In the results of regression analyses, we found that urinary cadmium levels significantly decreased as distance between residence and industrial complex increased after adjusting for age, gender, income, passive smoking and the length of residence. This result was opposite to that for lead levels. Our observations support the hypothesis that urinary cadmium levels in children are related to their proximity to an industrial complex.

• 한국노년학
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• v.41 no.2
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• pp.253-270
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• 2021

We examined if intergenerational proximity might be associated with upstream financial transfer from adult children to older parents, and whether adult child gender might moderate the association. We considered siblings' proximity to parents, as well as that of the adult child. Prior work conducted in the US and other countries has suggested that children living further from parents might provide financial support to compensate for instrumental support provided more by siblings living closer to parents. Data were drawn from the Korean Longitudinal Study of Ageing (2014). Our analytic sample consisted of older adults 60+ and their children aged 35 and 55. None of the children co-resided with parents. Parental households consisted of either widowed individuals or married couples. For within-family analyses, fixed effects and random effects regression models were estimated. Results suggest first, sons living within a 30-minute distance, or within an hour to two-hour distance provided more monetary support to married parents compared to daughters. Second, contrary to existing findings, greater financial assistance was provided by sons and daughters when no children lived within an hour distance from their parents. For widowed parents living alone, intergenerational proximity was not associated with the amount of financial transfer from adult children.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.78-91
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• 2017

In this study, we conducted a comparative study on user's perception and behavior on public system service (PSS) using institutionalism theory and MGA (multi-group analysis) methodology. In particular, this study focuses on how institutional isomorphism is applied to public system services and how MGA can be implemented correctly in a variance based SEM (structural equation model) such as PLS (partial least square). A data set of 496 effective responses was collected from pubic system users and an empirical research was conducted using three segmented models categorized by public proximity theory (public firms = 113, government contractors = 210, private contractors = 173). For rigorous group comparisons, each model was estimated by the same indicators and approaches. PLS-SEM was used in testing research hypotheses, followed by parametric and non-parametric PLS-MGA procedures in testing categorical moderation effects. This study applied novel procedures for testing composite measurement invariance prior to multi-group comparisons. The following main results and implications are drawn : 1) Partial measurement invariance was established. Multi-group analysis can be done by decomposed models although data can not be pooled for one integrated model. 2) Multi-group analysis using various approaches showed that proximity to public sphere moderated some hypothesized paths from quality dimensions to user satisfaction, which means that categorical moderating effects were partially supported. 3) Careful attention should be given to the selection of statistical test methods and the interpretation of the results of multi-group analysis, taking into account the different outcomes of the PLS-MGA test methods and the low statistical power of the moderating effect. It is necessary to use various methods such as comparing the difference in the path coefficient significance and the significance of the path coefficient difference between the groups. 4) Substantial differences in the perceptions and behaviors of PSS users existed according to proximity to public sphere, including the significance of path coefficients, mediation and categorical moderation effects. 5) The paper also provides detailed analysis and implication from a new institutional perspective. This study using a novel and appropriate methodology for performing group comparisons would be useful for researchers interested in comparative studies employing institutionalism theory and PLS-SEM multi-group analysis technique.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.9
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• pp.603-614
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• 2013

The popularity of mobile devices provides their users with a circumstance that services and information can be accessed wherever and whenever users need. Accordingly, various studies have been proposed personalized methods to improve accessibility of mobile users to information. However, since these personalized methods require users' private information, they gives rise to problems on security. An efficient way to resolve security problems is to estimate user information by using their online and offline behavior. In this paper, for this purpose, it is proposed a novel user information identification system that identifies users' personal and social information by using both his/her behavior on social network services and proximity patterns obtained from GPS data. In the proposed system, personal information of a user like age, gender, and so on is estimated by analyzing SNS texts and POI (Point of Interest) patterns, while social information between a pair of users like family and friend is predicted with proximity patterns between the users. Each identification module is efficiently designed to handle the characteristics of user data like much noise in SNS texts and missing signals in GPS data. In experiments to evaluate the proposed system, our system shows its superiority against ordinary identification methods. This result means that the proposed system can efficiently reflect the characteristics of user data.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1399-1408
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• 2004

Because there are so many spatio-temporal data in Moving Object Databases, a single disk system can not gain the fast response time and tota throughput. So it is needed to take a parallel processing system for the high effectiveness query process. In these existing parallel process-ing system. it does not consider characters of moving object data. Moving object data have to be thought about continuous report to the Moving Object Databases. So it is necessary think about the new Declustering System for the high performance system. In this paper, we propose the new Dechustering Policies of Moving objet data for high effectiveness query processing. At first, consider a spatial part of MBB(Minimum Bounding Box) then take a SD(SemiAllocation Disk) value. Second time, consider a SD value and time value which is node made at together as SDT-Proximity. And for more accuracy Declustering effect, consider a Load Balancing. Evaluation shows performance improvement of aver-age %15\%$ compare with Round-Robin method about $5\%\;and\;10\%$ query area. And performance improvement of average $6\%$ compare with Spatial Proximity method.

• Journal of Environmental Health Sciences
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• v.38 no.2
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• pp.95-104
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• 2012

Objectives: The goal of this study was to investigate the relationships between proximity to an industrial complex and blood lead levels and urinary cadmium levels. Methods: We conducted a questionnaire survey and analyzed blood lead and urinary cadmium levels using Atomic Absorption Spectrometry (AAs). Data was analyzed using logistic regression analysis. All statistical analyses were conducted with SAS software version 9.2. The distance between the residence and an industrial complex was calculated through a Geographical Information System (GIS). Results: A total of 967 residents living near a large petrochemical complex in Ulsan participated. The geometric mean levels of blood lead and urinary cadmium were $1.70{\mu}g/dl$ (male: $1.77{\mu}g/dl$, female: $1.67{\mu}g/dl$), and $0.72{\mu}g/g$ creatinine (male: $0.49{\mu}g/g$ cr. female: $0.89{\mu}g/g$ cr.), respectively. Blood lead and urinary cadmium levels both increased with age and were higher among smokers compared to never smokers. Both significantly showed a decreasing trend with rising income. Results from multiple logistic regression analysis showed that urinary cadmium levels for subjects aged less than 20 years old were negatively associated with distance from the industrial area to the residence. The results, however, indicated that the blood lead levels were positively associated with the distance. Conclusions: The results of this study support that proximity to an industrial complex is related to urinary cadmium values for children. A positive finding with blood lead can be explained by the ambiguity of lead exposure sources in the general environment.

• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.713-735
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• 2003

The purpose of this study was to investigate the effects of the characteristics of maternal social networks on maternal expectation for their own children to examine the path that social networks had an effect on the self-esteem and the emotional intelligence of children through maternal expectation for their own children. The data used in this study were collected from 524 fourth to sixth graders and their mothers residing in Daejeon using structured questionnaire. The major findings of the study were as follows : (1) Among social network characteristics, proportion of friends and neighbors, proximity, direction and interference had a negative effect, and proportion of mothers of child's friends, frequency of contact, intimacy, emotional support, service support had a positive effect on maternal expectation for their own children. (2) Among social network characteristics, proportion of mothers of child's friends had a direct effect and proportion of friends, neighbors, and mothers of child's friends, proximity, frequency of contact, intimacy, direction, emotional support, service support, and interference had an indirect effect on children's emotional intelligence through maternal expectation for their own children. (3) Among social network characteristics, proportion of kin and mothers of child's friends, intimacy, service support, material support and interference had a direct effect, and proportion of neighbors and mothers of child's friends, proximity, frequency of contact, direction, service support had an indirect effect on children's emotional intelligence through maternal expectation for their own children.

• Korean Journal of Human Ecology
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• v.18 no.2
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• pp.523-534
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• 2009

The purposes of this study were to identify brand equity factors influencing on brand preference and to investigate the effects of preference, price acceptability, distribution proximity, and appropriateness on brand performance of domestic and imported cosmetics brands. A total of 300 women aged between 20 and 49 years were surveyed on two domestic brands and two imported brands that were well-known to consumers during the month of September, 2006, in Seoul, Daejeon, Gyeonggi-do, and Chungcheong-do. The data were analyzed with factorial analysis, multiple regression analysis, ANOVA, Cronbach's ${\alpha}$, etc., using the SPSS 12.0. The result of the study included: 1) Four factors of brand equity were identified: brand image, social reputation, quality, and brand awareness. 2) Brand image, quality, appropriateness, and brand performance of the domestic brands were higher than those of the imported brands. But brand awareness of the imported brands was higher than that of the domestic brands. 3) Brand preference of the domestic brands was affected by social reputation, quality, brand image, and brand awareness in order of significance. And brand performance of the domestic brands was affected by brand preference, appropriateness, price acceptability and distribution proximity in order of significance. 4) Brand preference of the imported brands was affected by brand image, social reputation, brand awareness, and quality in order of significance. And brand performance of the imported brands was affected by appropriateness, price acceptability, brand preference, and distribution proximity in order of significance.