• Proceedings of the Korea Information Processing Society Conference
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• 한국정보처리학회 2001년도 춘계학술발표논문집 (상)
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• pp.379-382
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• 2001

본 논문에서는 WAP 포럼에서 제시한 WAP 프로토콜의 종단간 안전성 취약성을 분석하고 새로운 종단간 보안 세션을 위한 인증 프로토콜을 제안한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제35권3호
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• pp.607-616
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• 2015

The demand for cars has been so steadily increasing based on the economic growth that the number of registered cars reached 18,870,000 as of the end of December, 2012. Due to this, the demand for the parking lots also rises continuously. Because of the limited ground space, the buildings ever becoming larger, and the trend of underground parking spaces, recent parking spaces are generally constructed underground. Accordingly, the parking lot ramps slope is limited to less than 17% by relevant laws to ensure the driver safety. However, when a driver enters a parking lot ramps whose slope is slightly steep, he frequently experiences his car body colliding with ramp brackets and often sees the scratches on ramp floor. Thus, this study is intended to prevent any damage to a structure and to contribute to ensuring the riding comfort and safety of drivers and passengers by presenting the details of proper vertical curve to prevent the collision of vehicles with ramp brackets through a vertical analysis of the first and last parts of a parking lot ramps. Because it is necessary to decide the appropriate and suitable vertical slope of a parking lot ramps, this study first identified the problems through site inspection, targeting the parking lot ramps of large buildings frequently that are used by many random people. Next, the possibility of mutual collision was assessed through a theoretical analysis of the first and last parts of a parking lot ramps. Lastly, the vertical curve of a parking ramp was analyzed to estimate its details, which was presented in this study. In conclusion, if the vertical curve presented through this study is used, it will help prevent any damage to the cars and structures, ensure the riding comfort and safety of the drivers, and further reestablish the criteria for vertical installation of a parking lot ramps.

• Journal of the Korean Geotechnical Society
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• 제27권11호
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• pp.47-54
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• 2011

In this paper, longitudinal behaviors of a tunnel with respect to various conditions are analyzed, and a new equation of longitudinal deformation curve during tunnel expansion is proposed. Finally, the range of protection by a protector is investigated using the proposed equation. To achieve the objectives, numerical analysis according to the ground and expansion conditions is performed. The results show that the range of protection, when a 2 traffic lane tunnel is expanded to 4 traffic lanes, should cover at least 24m to backward and 35m forward.

• Korean Journal of Culture and Social Issue
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• 제28권3호
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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.

• Journal of Internet Computing and Services
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• 제21권4호
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• pp.77-85
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• 2020

The purpose of this study is to explore the changing trajectory of using educational media through longitudinal data analysis. We categorize the feature of using educational media as usage for learning, usage for information, and usage for the game. We explore the longitudinal changing patterns of usage for learning, usage for information, and usage for the game by LGM(Longitudinal Growth Modeling). We also find the gender difference between these longitudinal changing trajectories. We used 3,499 samples of KYPS middle school second-grade panel data. We found these results: (a) Both usage for learning and information are statically significant variability in initial level and rate of change. Both of the changing trajectories have increased. (b) Girls have a higher rate of the change both in the usage of learning and information than boys over time. (c) There is a statistically significant individual variability in initial levels and rate of change in the usage of the game over time. (d) Boys have a higher rate of initial value than girls in the usage of games, but there is no significant difference in the rate of changing trajectories.

• (The)Korea Educational Review
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• 제23권1호
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• pp.205-230
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• 2017

Drawing on third to fifth wave data from the Longitudinal Study of North Korean Migrant Youths' Education, we examined the longitudinal relationship between social capital of North Korean Migrant Youths and school adjustment using latent growth modeling(LGM). Specifically, we sought to answer the following research questions: Do social capital and school adjustment among North Korean Migrant Youths change over time? Is there a relationship between the changes in social capital and school adjustment among these students? Our LGM results showed that trends in social capital and school adjustment among these students were not fixed but changed over time. While the social capital developed by these students was found to influence school adjustment at the time of its development, it did not continue to influence changes in school adjustment over time. Changes in school adjustment of North Korean migrant youths were affected by changes in social capital. These results suggest that there is room for gradual improvement of school adjustment level by strengthening social capital of North Korean migrant youths.

• Korean Journal of Culture and Social Issue
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• 제29권2호
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• pp.223-252
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• 2023

The aim of this study is to examine the longitudinal mediation effect of coping strategies(emotion-focused, problem-focused, and maladaptive) on the relationship between perceived stress during the COVID-19 andemic and psychological distress(negative affect, depression, anxiety, and anger). ). Also, This study sought to find generational differences between coping strategies used during the COVID-19 pandemic. The participants were 941 adult aged between twenties and seventies. The final participants were recruited on two separated longitudinal time points, Time 1 and Time 2. The result were as follows: Only Maladaptive coping strategy(Time 2) had a mediating effect on the relationship between COVID-19 stress(Time 1) and psychological distress(Time 2). . The result of the generation-based multi-group analysis did not yield significant differences in the use of coping strategies. This study is meaningful that it longitudinally examined the psychological distress of adults during the COVID-19 pandemic. Implications, limitations and directions for future research are presented.

• Journal of KIISE:Information Networking
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• 제31권6호
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• pp.608-619
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• 2004

Application layer multicast(ALM) has been developed as an alternative to support the multi-receiver applications due to the slow deployment of IP multicast. Unlike routers in IP multicast, end systems participating in a ALM session are not optimized for relaying data and have various processing and network capacity. Therefore, with the increased role of end systems, the delay incurred at the end systems occupy large portion of the end-to-end delay. In this paper, we model the end system delay of ALM sessions and analyze its impact on the performance of the existing ALM schemes. Furthermore, we propose an enhanced scheme, based on the existing mesh-based scheme, which reflects the end system delay We also evaluate the performance of the proposed scheme by simulation and show that it reduces the end-to-end delay compared with the existing scheme.

• The Korean Journal of Applied Statistics
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• 제37권1호
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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.

• Phonetics and Speech Sciences
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• 제11권1호
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• pp.41-49
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• 2019

An end-to-end speech recognition model consisting of a single integrated neural network model was recently proposed. The end-to-end model does not need several training steps, and its structure is easy to understand. However, it is difficult to understand how the model recognizes speech internally. In this paper, we visualized and analyzed the attention-based end-to-end model to elucidate its internal mechanisms. We compared the acoustic model of the BLSTM-HMM hybrid model with the encoder of the end-to-end model, and visualized them using t-SNE to examine the difference between neural network layers. As a result, we were able to delineate the difference between the acoustic model and the end-to-end model encoder. Additionally, we analyzed the decoder of the end-to-end model from a language model perspective. Finally, we found that improving end-to-end model decoder is necessary to yield higher performance.