• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.161-168
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• 2009

Recently, use of various position base servicesthat collect position information for moving object and utilize in real life is increasing by the development of wireless network technology. Accordingly, new index structures are required to efficiently retrieve the consecutive positions of moving objects. This paper addresses an improved trajectory split algorithm for the purpose of efficiently supporting spatio-temporal range queries using index structures that use Minimum Bounding Rectangles(MBR) as trajectory approximations. We consider volume of Extended Minimum Bounding Rectangles (EMBR) to be determined by average size of range queries. Also, Use a priority queue to speed up our process. This algorithm gives in general sub-optimal solutions with respect to search space. Our improved trajectory split algorithm is going to derive minimizing volume of EMBRs better than previously proposed split algorithm.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.275-278
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• 2004

정보기술의 발달과 교통기술의 발달로 인해 현재 많은 정보화 시스템들이 등장하고 있다. 최근 GPS(Global Positioning System)의 보급과 위치정보의 중요성이 대두되면서 위치정보기반 서비스(LBS, Location Based Service)의 개발이 눈에 띄게 두드러지고 있다. 사용자 위치 정보 획득 기술이 발달함에 따라 한편으로는 사용자의 위치정보가 악용되어 사생활 침해와 같은 문제점도 나타나고 있다. 본 논문은 사용자의 위치정보를 기반으로 이동경로 혹은 궤적을 패턴으로 분류하고 일반적인 사용자의 생활권역의 경로에 대해 학습을 실시하여 위치기반의 서비스의 사생활 침해 문제에 대한 해결방법을 제시한다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.285-287
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• 2010

최근 모바일 장비 및 시스템의 발달로 위치정보를 이용한 많은 서비스들이 나오고 있다. 이러한 위치정보 서비스와 맞물려 DB시스템들과 위치 정보의 저장을 지원하게 되었다. 하지만 현재의 DB시스템들은 위치 정보의 저장은 지원을 하지만, 이동 객체의 궤적을 저장을 지원 하지는 않고 있다. 본 논문에서는 공간 데이터베이스로 많이 활용되고 있는 PostGIS에서 이동 궤적을 저장할 수 있도록 확장한 시스템을 설계하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2057-2064
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• 2010

With the development of wireless network technology, the location information of a spatiotemporal object which changes their location is used in various application. Each spatiotemporal object has many location information, hence it is inefficient to search all trajectory information of spatiotemporal objects for a range query. In this paper, we propose an efficient method which divides a trajectory and stores its division data on restricted storage space. Using suboptimal split algorithm, an extended split algorithm that minimizes the volume of EMBRs(Extended Minimum Bounding Box) is designed and simulated. Our experimental evaluation confirms the effectiveness and efficiency of our proposed splitting policy

• Korean Journal of Social Welfare Studies
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• v.40 no.3
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• pp.377-406
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• 2009

This study used laten class growth analysis to identify discrete developmental patterns of delinquent behaviors in adolescence. This present article also examined associations among these trajectories to determine how the development of delinquent behaviors relates to protective and risk factors, which include parental monitoring, attachment with parent, association with deviant peers, self-control, and negative stigma from others. Four-wave panel data from a Korea Youth Panel Study were used for the latent class growth model analysis. The sample consisted of 3,446 adolescents who were assessed at 4 measurement waves with approximately 1-year interval. Four trajectories of delinquent behaviors emerged: delinquency persistence, delinquency increaser, delinquency decreaser, normative group(almost no delinquent behaviors). Association with deviant peers had the most proximal strong influence on the probability of being in the delinquency increaser and delinquency persistence group compared, noed to the normative group. Parental monitoring, self-efficacy and negative stigma also differentiated the four delinquent behavior trajectories from one another after controllig for socio-demographic variables. The study suggested that there is a significant heterogeneity in the timing and change rate of delinquency progression. Adolescent delinquency prevention and intervention programs will need to consider this heterogeneity and enhance attention to protective and risk factors depending on the subpopulation.

• Journal of the Korean Society of Child Welfare
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• no.59
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• pp.183-208
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• 2017

The purpose of this study was to identify groups depending on the change trajectory of child maltreatment in childhood and early adolescence. For this study, the data from waves two through six (2011-2015) of the Korean Children and Youth Panel Survey (KCYPS) were used. Participants included first-grade (n=2,300) and fourth-grade (n=2,325) elementary school students. A latent class growth model (LCGM) using Mplus 7.21 was adopted to classify the types of developmental trajectories of child maltreatment. The main results were as follows: First, in physical abuse, childhood from the second to the sixth grades was classified into four groups: decreased, low maintenance, increased, and no maltreatment type. In addition, early adolescence from the fifth grade of elementary school to the third grade of middle school was also classified into the same types. Second, in emotional abuse, childhood was classified into three groups: decreased, increased, and no maltreatment type. Early adolescence was classified into four groups: decreased, low maintenance, increased, and no maltreatment type. Third, in neglect, childhood was classified into four groups: maintenance, low decreasing, low increasing, and no maltreatment type. Early adolescence was classified into three groups: maintenance, low increasing, and no maltreatment type. According to the change of child maltreatment by developmental period, physical abuse continued from childhood to early adolescence, whereas emotional abuse and neglect increased in early adolescence compared to childhood. This study is meaningful in classifying latent classes depending on maltreatment types. Theoretical and practical implications were suggested based on the study results.

• Journal of the Korean Society of Child Welfare
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• no.54
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• pp.145-172
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• 2016

The purpose of this study was to examine whether parenting attitudes would have an effect on the developmental trajectories of school adjustment for adolescents in out-of-home care. Additionally, we hypothesized that this model would be different between boys and girls. In this study, we analyzed three waves of data collected from 341 adolescents living in residential facilities, group homes or foster homes by using cluster sampling methods. Growth-curve longitudinal analysis was conducted, and the results indicated that levels of school adjustment had increased from the 1st through the 3rd grade of middle school. Positive parenting attitudes had a positive impact on initial school adjustment and rate of change, whereas negative parenting attitudes had a negative impact only on the initial school adjustment. Second, multi-group analysis revealed that there were group differences between boys and girls in their initial school adjustment by positive parenting attitudes. Based on these results, this study discussed further suggestions to increase school adjustments for adolescents in out-of-home care.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.2
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• pp.85-90
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• 2017

Various mobile devices are spreading in recent developments in mobile computing environments. Especially the popularity of mobile devices equipped with GPS has become widespread, and various application services utilizing location information are born. In this paper, we propose a system model for storing and managing the trajectory of moving objects, which is the set of location information of moving objects acquired in continuous time, and the UDF (User-Defined Functions) based trajectory index method which can quickly query the large data set of moving object and the Pre-Materialized table method. Then we compare and evaluate the performance of each method through experiments. Experimental results show that the Pre-Materialized table method is about 1.2 times faster than the UDF based trajectory index method on execution time.

• 한국공간정보시스템학회:학술대회논문집
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• 2003.11a
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• pp.153-158
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• 2003

최근 이동 통신 기술과 GPS 기술의 발달은 실시간으로 이동하는 차량이나 비행기 등과 같은 이동 객체의 위치 정보 서비스를 가능하게 하였고, 이로 인해 이동 객체의 정보를 빠르게 검색하고 저장하기 위한 기술에 대한 연구가 활발히 진행되고 있다. 지금까지의 연구는 이동 객체의 과거 궤적 정보, 현재 및 미래 정보를 다루기 위한 구조가 각각 분리되어 연구되어 왔다. 하지만 이동객체는 시간의 흐름에 따라 연속적으로 변화하기 때문에 과거 정보와 현재 정보를 별도로 관리할 경우, 빈번한 위치 갱신이 발생하는 이동 객체의 환경에서는 심각한 처리비용이 요구된다. 따라서 이 논문에서는 이동 객체의 위치 정보를 효과적으로 관리하기 위하여 이동 객체의 과거 궤적정보 뿐만 아니라 현재의 정보까지도 하나의 색인 내에 통합하여 관리하는 방법을 제안한다. 제안된 방법에서는 범위 질의와 같은 좌표 기반의 질의뿐만 아니라 이동 객체의 궤적과 관련된 질의까지도 처리 가능하도록 기존의 TB-tree를 확장한다 또한 기존의 이동 객체 관리 기법들에서 처리하던 이동 객체의 궤적 정보를 저장하기 위한 방법을 개선하여 이동 객체 위치 정보의 중복저장 문제를 해결하고, 전체 색인의 크기를 크게 줄일 수 있는 방법을 제안한다. 그리고 현재 정보의 관리를 통해 새로운 데이터 삽입 시 방문하는 node의 수를 줄이고, 삽입 시간을 단축하는 방법을 제시한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2188-2194
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• 2011

With the development of wireless network technology, Storing the location information of a spatiotemporal object was very necessary. Each spatiotemporal object has many unnecessariness location information, hence it is inefficient to search all trajectory information of spatiotemporal objects. In this paper, we propose an efficient method which increase searching efficiency. Using EMBR(Extend Minimun Bounding Rectangle), an LinearMarge split algorithm that minimizes the volume of MBRs is designed and simulated. Our experimental evaluation confirms the effectiveness and efficiency of our proposed splitting policy.