• The Journal of Korean Association of Computer Education
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• v.23 no.1
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• pp.53-61
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• 2020

In the information society, the ability of learners to use computers to conduct self-directed learning is important. Indeed, the higher the computer's ability to use computers, the more the academic achievement needs to be analyzed. The purpose of this study was to identify longitudinal trajectories of student awareness of ICT literacy and frequency of computer use. We also examined the effects of the longitudinal patterns on academic achievement and college major choice. A non-parametric approach, K-means for longitudinal data(KML) algorithm, was conducted using 9-year longitudinal data from Seoul Education Longitudinal Study (2010-2018). Findings indicated that a pattern presenting a higher awareness of ICT literacy and frequency of computer use showed better academic achievements and was likely to prefer to choose engineering-related majors.

• Journal of Convergence for Information Technology
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• v.12 no.5
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• pp.100-106
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• 2022

A longitudinal study refers to a research method based on longitudinal data repeatedly measured on the same object. Most of the longitudinal analysis methods are suitable for prediction or inference, and are often not suitable for use in exploratory study. In this study, an exploratory method to analyze longitudinal data is presented, which is to find the longitudinal trajectory after determining the best number of clusters by clustering longitudinal data using self-organizing map technique. The proposed methodology was applied to the longitudinal data of the Employment Information Service, and a total of 2,610 samples were analyzed. As a result of applying the methodology to the actual data applied, time-series clustering results were obtained for each panel. This indicates that it is more effective to cluster longitudinal data in advance and perform multilevel longitudinal analysis.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.267-279
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• 2015

The study aimed to examine the longitudinal relationship between addictive use of mobile phones and learning activities for elementary school students and to analyze (1)temporal changes of the addictive use of mobile phones and learning activities, (2)temporal relationship between them, and (3)multiple and complex group analysis across gender on the relationship. For the study, 3-year longitudinal data(2010-2012) of the Korean Children and Youth Panel Survey and autoregressive cross-lagged modeling were used. The findings showed that the addictive use of mobile phones and learning activities had a significant positive effect on the future selves of children over time. The addictive use of mobile phones influenced positively subsequent learning activities, but, the learning activities did not affect the addictive use of mobile phones. Further, there were no significant gender differences in the longitudinal relationship. The study provided the useful data to make guidelines on how to protect mobile phone addiction for elementary school students.

• Information Systems Review
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• v.12 no.3
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• pp.159-175
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• 2010

Although many studies have analyzed and identified the importance of intrinsic motivation in the acceptance of information technology (IT), especially hedonic systems such as online game and online shopping, the acceptance of programming languages such as Java were not studied in a view of intrinsic motivations. The objective of this study was to investigate the effects of intrinsic motivation on the acceptance of programming language by the longitudinal analysis. In the service of the objective, we suggested the research model which included both intrinsic and extrinsic motivations and longitudinally extended by belief updating theory. For the validation of this model, the university students who participated Java class were surveyed twice, and the suggested research were analyzed by partial least square (PLS). In result, most of the suggested hypotheses were supported.

• Korean Journal of Culture and Social Issue
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• v.28 no.3
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• pp.331-352
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• 2022

This study used a latent growth curve models(LGCM) to examine longitudinal changes in youth's game usage, self-control and the longitudinal mediation effect of adaptive game use in the relationship between game usage and self-control. A four-year longitudinal data of 863 adolescents from the Game User Panel Survey, provided through participation in the 2019 Game User Panel Research Conference hosted by the Korea Creative Contents Agency, was used to verify the longitudinal mediation effect of adaptive game use. SPSS 21 was used to verify the normality of variables from each wave, and to conduct correlation analysis. Mplus 6.12 was used to verify the longitudinal mediation effect. The results are as follows. First, game usage, self-control and adaptive game yielded linear temporal growth. Second, latent growth curve models showed that the direct effect of game usage on self-control was insignificant, but game usage had a significant indirect effect on self-control through adaptive game use. Continuous adaptive gaming increased self-control. Third, sobel test results showed that both the initial value and change rate of adaptive game use had a full-mediation effect, confirming the longitudinal mediation effect. This study verified the longitudinal change of self-control affected by change in game usage and adaptive game use.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.289-291
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• 2003

IP멀티캐스트가 현재 보편적 서비스로 사용되지 못하는 한계로 인하여 그 대안으로 응용 계층 멀티캐스트 기법들이 제안되고 있다. 기존의 응용 계층 멀티캐스트의 성능 분석 기준으로 네트워크 자원의 효율적 사용면을 고려하여 스트레스, 스트레치와 전송 트리 관리 비용등이 사용되었다. 그러나, 응용 계층 멀티캐스트는 데이터의 전송이 참가자인 종단 시스템에 의해 이루어지고, 종단 시스템은 범용 장비로서 데이터 전달에 최적화된 성능을 갖지 못한다. 따라서, 데이터 전달을 위해 종단 시스템에서의 처리 지연이 발생하고 이로 인한 종단간 데이터 전송 지연에 영향을 끼치게 된다. 본 논문에서는 종단 시스템에서의 데이터 전달을 위한 전달 지연 시간을 모델링 하고, 대표적 다대다 응용 계층 멀티캐스트 기법인 End­system Multicast와 NICE에 대하여 종단 시스템에서 발생하는 처리 지연 시간이 전체 참가자간의 데이터 전송 지연 시간에 미치는 영향을 분석한 결과를 기술한다.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.743-755
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• 2016

The objectives of this research is to examine: 1) how the rates of adolescents' BMI change over time in terms of the state level; and 2) development difference in the state level of BMI in terms of children's obesogenic behaviors from 1999 to 2011. Data were drawn from the 1999-2011 Youth Risk Behavior Survey in the United States (N=260, 293, grades 9-12, and 27 states). Ordinary least squares regression and hierarchical linear modeling were utilized to capture a longitudinal time effect of school-aged adolescents' obesity rates across the states, controlling for demographics and nutrition- and physical activity-related behaviors. The state's level of children's BMI percentile was significantly associated with longitudinal time. Longitudinal time effect across the states appears to play an important factor associated with children's decrease of BMI percentile. Therefore the states' implementation of physical activity and nutritional policies seems to be effective for preventing and reducing childhood obesity during last decade. More attention should focus on enforcing the policy and overcoming current barriers in order to minimize children's obesogenic factor.

• The Journal of Information Systems
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• v.18 no.4
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• pp.105-130
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• 2009

정교화가능성모형과 기술수용모형에 의해 정보기술 수용의 설득과정을 시도한 연구들이 이론적으로 미친 영향은 매우 크다. 그러나 이들 연구의 대부분은 횡단면적 접근에 기반한 정적 모형을 사용했기 때문에 시간 흐름에 따른 변수 간의 관계 변화를 적절히 설명하지 못하고 있다. 가령, 교육 프로그램을 통한 정보기술 수용은 일정기간의 시간을 요하는데 설득경로가 유용성의 지각에 미치는 영향력은 달라질 수 있다. 따라서 정보기술 수용과정을 충분히 규명하기 위해서는 기존의 연구모형은 종단적으로 확장되어 시간 흐름에 따른 시스템 사용을 평가해야 한다. 한편 정보기술수용 연구에서 내재적 동기의 중요성이 강조되고 있음에도 불구하고 수용 설득과정에서 내재적 동기에 대한 고려는 별로 없었고 대부분의 연구는 유용성과 같은 외재적 동기를 중심으로 이루어졌다. 본 연구의 목적은 정보기술수용 설득과정의 이해를 넓히기 기존 연구에서 제시된 연구모형에 내재된 동기에 관련된 변수를 포함하고 전체적인 모형을 종단적으로 확장했고, 실증적 검증을 위해 정규 대학과정 과목의 학생들을 대상으로 두 번에 걸친 표본 조사를 하였다.

• The Korean Journal of Applied Statistics
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• v.37 no.1
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• pp.61-72
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• 2024

The purpose of this study is to investigate retest reliabilities in longitudinal study, the same test is administered repeatedly over time. Linear mixed models were used to establish various situations of tests occurred in longitudinal study. Combination of two types of true value and three types of systematic error was considered. In order to apply the models to real longitudinal data, height data from the Berkeley growth study and vocabulary score data from the University of Chicago experimental school were used. Using the mixed model, there is an advantage that the reliability can be determined by selecting the covariance structure of the true value and the error separately. However, in order to properly analyze the reliability, researchers need to consider variations that can occur in measurement, such as characteristics of subject, the test, and the the treatment applied in the study. And the proper model should be selected and the quality of the measurement should be evaluated for each trial.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.65-79
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• 2020

With the rapid development of China's economy, the aviation industry, as an important part of transportation services, has undoubtedly achieved rapid development. However, there is hardly any academic work that was based on the development of the top airlines in the Chinese airline industry. Hence, this study provides empirical research that takes into account the longitudinal development of the top 20 airlines in China from 2009 to 2018. The throughput volumes (cargo and passenger) of the airlines were analyzed by concentration indicators, namely the concentration ratio (CR), the Herfindahl- Hirschman index (HHI), the Gini coefficient, and the shift-share analysis (SSA). In this paper, the top 20 airlines have been analyzed in terms of the passenger and cargo throughput from 2009 to 2018. The calculation results of CR6, HHI and the Gini coefficient show that the airlines were extremely deconcentrated. In addition, by comparing the ABSGR of passenger and cargo throughput, it is shown that China's aviation industry is dominated by four airlines- Air China, China Eastern Airlines, China Southern Airlines and Hainan Airlines. In the future study, it is necessary to explore growth strategies to find niche markets for passenger and cargo transportation.