• Journal of Korean Public Health Nursing
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• v.34 no.3
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• pp.325-340
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• 2020

Purpose: This study was undertaken to identify the effects of a camp-type group counseling program based on the self-determination theory, for controlling smartphone usage amongst university students. The program consisted of smartphone overdependence, basic psychological needs, and adaptation to college life. Method: This was a quasi-experimental research with a non-equivalent control group design (pre-test and post-test design). A total of 38 freshmen (17 experimental and 21 control) participated in the study. Experimental subjects attended a two nights and three days camp, where the group counseling program included meetings for basic psychological needs (eg., autonomy, competence, and relatedness). Results: This study showed significant differences in basic psychological needs (Z=-2.91, p=.003) and adaptation to college life (Z=-3.47, p<.001). Although no significant difference was obtained in the degree of smartphone overdependence (p=.194), mean score of the experimental group pre-test and post-test changed from the level of potential risk users to general users. Conclusion: The current findings indicate that by considering the basic psychological needs and adaptation to college life, our program could be an effective intervention for controlling smartphone usage amongst college students. Therefore, we propose that a camp-type counseling program could be considered for application as group therapy for programs associated with preventing smartphone overdependence.

• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.1-11
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• 2018

Multivariate process control has become important in various applied fields. For instance, there are many situations in which the simultaneous monitoring of multivariate quality characteristics is necessary for the manufacturing industry. Despite its importance, its practical usage is not as convenient because it is difficult to identify the source of the out-of-control signal in a multivariate control chart. In this paper, we will introduce how to detect the source of the out-of-control by using confidence intervals for new observations, and will discuss the identification and interpretation of the out-of-control variable through simulation studies.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.6
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• pp.477-486
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• 2001

Many physical systems can be modeled by incorporating continuous and discrete event nature together. Such hybrid systems contain both continuous and discrete states that influence the dynamic be-havior of the systems. There has been an increasing interest in thers types of systems during the last dec-ade, mostly due to the growing usage of computers in the control of physical plants but also as a result of the hybrid nature of physical processes. The stability theory for hybrid systems is considered as extension of Lyapunov theory where the existence of an abstract energy function satisfying certain properties verifies stability, called multiple Lyapunov theory. In this paper, a hybrid stabilizing controller is proposed using the control Lyapunov function method and multiple Lyapunov theory, and the proposed method is applied to lon-gitudinal spacing control in a vehicle platoon for intelligent transportation systems(ITS).

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.5
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• pp.147-156
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• 2022

Industrial control systems that manage and maintain various industries were mainly operated in closed environment without external connection, but with the recent development of the Internet and the introduction of ICT technology, the access to the industrial control system of external or attackers has become easier. Such incorrect approaches or attacks can undermine the availability, a major attribute of the industrial control system, and violation of availability can cause great damage. In this paper, when issuing commands in an industrial control system, a verification group is formed using a random list to verify and execute commands, and a trust score technique is introduced that applies feedback to the verification group that conducted verification using the command execution result. This technique can reduce overhead generated by random generation in the process of requesting command verification, give flexibility to the verification process, and ensure system availability. For the performance analysis of the system, we measured the time and gas usage when deploying a smart contract, gas usage when verifying a command. As a result, we confirmed that although the proposed system generates a random list compared to the legacy system, there was little difference in the time when it took to deploy smart contract and that the gas used to deploy smart contract increased by about 1.4 times in the process of generating a random list. However, the proposed system does not perform random operations even though the operation of command verification and confidence score technique is performed together during the command verification process, thus it uses about 9% less gas per verification, which ensures availability in the verification process.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.120-140
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• 2016

The purpose of this study is to assess the green space considering functional characteristics in order to provide the base data for efficient green planning and management. The study area was the park-type green spaces in Daegu and the functions were limited in nature-ecological, environment-control, and usage functions. Thirteen indicators were selected from the literature review and MCB analysis of expert survey. The weightings of functional indicators were established through AHP analysis of expert survey. According to the results of functional assessment, Naengcheon amusement, Deagu sports, and Dalchang amusement parks had scores of more than 80 in the case of nature-ecological function. Fifteen parks such as Bokhyeon, Manchon, and Cheonnae parks had scores of more than 75 in terms of environment-control function and eleven parks such as Suseong, Dalseong, and Wolbae parks had scores of more than 80 in usage function. The findings from this study can be used as the base data and guideline for construction of new park-type green space and continuous management and remodeling of current green space.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.339-347
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• 2015

Differences in characteristics of flora and environmental factors of geomorphology, hydrology, water quality and soil were investigated in the shoreline of total 35 reservoirs according to their usages of waterpower generation, agricultural water supply, residential and industrial water supply and flood control in Korea. The number of plant species, floral structure and characteristics of species traits in the shoreline of reservoirs were different according to their usage. From the results of stepwise regression analysis, the total number of vascular plant species was increased at the environment of the higher flood frequency at the median water level and the longer exposure duration of the shoreline. The results of principal coordinates analysis and cluster analysis showed that the shoreline flora was classified as the 3 types of 1) flood control and residential and industrial water supply, 2) agricultural water supply and 3) waterpower generation reservoirs. The water level fluctuation, flood frequency at the median water level, lake water quality index and exposure duration of the shoreline were selected as important environmental factors affected on the characteristics of shoreline flora. The species richness of total flora and hydrophytes, especially submerged macrophytes, were much higher in the reservoirs for the purpose of the waterpower generation in which mesotrophic water quality and stable water levels were maintained. Annual or biennial ruderals were established on the ephemeral drawdown zone of flood control, residential and industrial water supply reservoirs which have oligotrophic or mesotrophic water quality and wide range of water level fluctuation. The floating hydrophytes were differentially dominated in the littoral zones of the agricultural water supply reservoirs with a mesotrophic or eutrophic water quality and a medium water level fluctuation. In conclusion environmental factors related to water level fluctuation and water quality were different and then the floral characteristics of shoreline were distinguishable according to usage of Korean reservoirs.

• Korean Journal of Culture and Social Issue
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• v.29 no.3
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• pp.275-304
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• 2023

This study aimed to examine the mechanisms underlying digital game usage behavior by applying the Theory of Planned Behavior and the Balance Theory. It investigated the influences of attitude, subjective norms, and perceived behavioral control on the intention to use digital games, as well as the differences in the application of the Theory of Planned Behavior model based on the balance state among individuals, significant others, and digital games. A total of 315 responses from adult PC game users were collected through an online survey conducted from October 21 to 25, 2021, and were analyzed using multiple regression analysis. The results revealed that attitude and perceived behavioral control had a significant positive impact on the intention to continue using digital games, while subjective norms did not exert a significant influence. By categorizing groups into balanced, unbalanced, and imbalance states based on the balance relationship, the application of the Theory of Planned Behavior model showed that in the unbalanced and imbalance groups, both perceived behavioral control and attitude had a positive impact on the intention to continue using digital games. However, in the balanced group, attitude only had a positive impact on the intention to continue game usage. This study contributes to understanding digital game users by examining both individual psychological factors and the influence of others on digital game usage behavior.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.932-935
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• 2004

In this paper, we present a framework that is easy to develop, modify, maintain and extend a control and monitoring software for any kinds of instruments. The presented framework is composed of three XML documents (IID, MAP, and CMIML) and two tools (Virtual Instrument Wizard, Generator). Interface information about behaviors and states of instruments is written on IID. Mapping information between the interface information in IID and API of a real instrument driver is written on MAP. Finally information about control and monitoring software is written on CMIML. IID, MAP and CMIML are written with XML format to provide common usage and platform independence of the suggested framework. VI Wizard generates CMIML (platform independent intermediate document) using IID and existing CMIML, and Generator generates source code of a control and monitoring software (platform dependent code) automatically using CMIML and MAP. The suggested framework that automatically generates control and monitoring software based on GUI provides easy development and maintenance. Also, reusability can be increased by reusing platform independent software description documents.

• Korean Journal of Child Studies
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• v.31 no.5
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• pp.47-61
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• 2010

This study examined the moderated effects of self-control on the relationship between elementary school children's excessive use of the Internet and their stress levels. The participants were 403 elementary school children from Chungnam-do. The instruments used were the 'Internet Addiction Autodiagnosis Scale (K-Scale)', the 'Stress Scale' and the 'Self-control Rating Scale'. The collected data were analyzed by t test, F test and the Scheffe test for a post hoc test, Pearson's partial correlation and stepwise multiple regression, and Cronbach's ${\alpha}$ for reliability by SPSS program (17.0 version). The results were as follows : First, it was found that there were significant differences in terms of excessive use of the Internet, stress levels, and self-control by gender, grade, academic achievement, the beginning year of first Internet access and the number of hours of Internet usage hours per day. Second, there were significant positive correlations between excessive use of the Internet (r = .40, p < .001) and stress levels (r = .44, p < .001) and the immediate satisfaction of self-control. Finally, the immediate satisfaction of self control was seen to moderate the relationships between the total scores for the excessive use of the Internet and stress levels and between withdrawal of excessive use of the Internet and the accompanying stress levels.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.528-533
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• 2002

인터넷 인프라의 보급과 이용인구의 급속한 증가는 off-line을 통해서 물리적으로 획득하던 다양한 정보와 자료를 인터넷을 통해서 쉽고 빠르게 이용할 수 있는 서비스를 창출하고 있다. 그러나 이와 같은 서비스를 통해서 제공되는 컨텐츠의 저작권 문제와 불법 복제 등과 같은 피해도 함께 증가하고 있다. 이런 문제를 해결하기 위해서는 컨텐츠에 접근하고 이용할 수 있는 자격을 가지고 있는 사용자만이 해당 컨텐츠를 정상적으로 이용할 수 있도록 하는 Access Control(AC) 기술이 함께 연구되고 있다. 현재 상용화되어 있는 CAS와 DRM은 PBT 형태의 대표적인 AC 기술이라 할 수 있다. 본 논문에서는 [5]에서 제시된 PFT 기반의 AC를 위한 Security Architecture를 살펴보고, 효과적인 운영을 위한 PFT 기반의 새로운 AC 구조를 제시한다.