• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.167-174
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• 2010

Recently the distributed topology control algorithm for constructing the Recrystallization Topology in the unstructured peer-to-peer network was proposed. In this paper, we prove that such a hierarchical topology is a scale-free power-law network. We present a model of a construction process of the distributed protocol, and analyze it based on a mean-field approximation and the continuum theory, so that we show that the constructed Recrystallization Topology is a scale-free network. In the proposed model, all nodes are born with some initial attractiveness and the system incorporates the rewiring of some links at every time step. Some old links are removed with the anti-preferential probability, and some new links are added with preferential probability. In other words, according to the distributed algorithm, each node makes connections to the more-preferential nodes having higher hit-ratio than other nodes, while it disconnects the anti-preferential nodes having lesser hit-ratio. This gives a realistic description of the local processes forming the recrystallization topology in unstructured peer-to-peer network. We calculate analytically the degree distribution. The analytic result indicates that the constructed network is a scale-free network, of which the scaling exponent is 3.

• Korean Journal of Childcare and Education
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• v.11 no.6
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• pp.133-151
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• 2015

The aim of this study was to examine how children's self control, mother's addiction to smart devices and parenting behavior influence the way young children used smart devices. Participants were made up of 166 preschoolers and their mothers. Descriptive analysis, Pearson's correlation coefficient, and hierarchical regression analysis were used for statistical analysis. The results were as follows: First, children in their early childhood years used smart devices once or twice a week, for ten to thirty minutes, mainly during weekends. Children in their early childhood stage started to use smart devices before reaching the age of 3, and accessed them through their parents, usually along with their siblings. Parents allowed their children to use smart devices for fun and entertainment, with only 66.3% of them setting rules. Second, the mother's tendency to be immersed in smart devices, overprotection and permission were positively correlated to young children's overusage of smart devices, whereas geniality, encouragement, setting limits, and children's self control were negatively correlated. The study also found that the mother's tendency of being immersed in smart devices was the most influential factor for their children's overusage of smart devices. The value of this study lies in providing practical suggestions for children's smart device usage and parental education programs.

• Journal of Gifted/Talented Education
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• v.25 no.4
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• pp.607-628
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• 2015

The purpose of this study was to compare gifted and non-gifted high school students on their perceptions of success, grit, aspirations, and achievement goal orientation. Of the 550 high school students surveyed from 4 high schools (i.e., two schools for gifted, two school for non-gifted) in three metropolitan cities, Korea, 496 (i.e., 153 gifted and 343 non-gifted) completed and returned the questionnaire yielding a total response rate of 90.18%. Measures of students' grit (i.e., consistency of interest, and perseverance of effort), aspirations (i.e., intrinsic aspirations - physical fitness, self-growth, affiliation, community contribution, and extrinsic aspirations - financial success, image, fame), achievement goal orientation (i.e., mastery, performance approach and performance avoidance), and perceptions of success (i.e., Success in life is pretty much determined by forces outside our control.) were administered. It was found that the majority of gifted students and non-gifted students perceived that "success is outside our control.", and chose 'hard-working' as the most influential factor on their success. 60.4% of non-gifted students chose 'wealthy family background' as the other most influential factor, whereas only 48.2% of gifted did. Gifted students had higher 'consistency of interest' and 'mastery goals' than non-gifted students. Hierarchical multiple regression analyses showed that grit (i.e., perseverance of effort) was the crucial contributors for enhancing both gifted and non-gifted students' mastery goals and performance approach goals. Results are discussed in relation to theoretical implications and school settings.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.452-459
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• 2018

Conventional fire fighting robots are controlled by a remote control to monitor the fire scene or to suppress the fire. However, this method has a problem that it takes a long time to prepare robot and input it to fire place in the golden time after the fire, so that it can not sufficiently serve as a fire fighting robot. Using the autonomous driving fire monitoring robot, when a fire signal is generated, in conjunction with a fire receiver a moving robot takes a video of the fire scene and delivers the image to the fire department, so that the fire fighter can decide if it is real fire or not. Thereby it is possible to prevent a sudden spread of an accident by providing a quick judgment opportunity and at the same time suppressing the fire early. In this paper, we propose an architecture of the autonomous mobile fire monitoring robot and the communication protocol required for the robot to work with the fire receiver. A communication protocol is designed to control multiple fire monitoring robots in real time, and a communication with a fire receiver is designed as a hierarchical network to serve as an interface of an Ethernet network using wireless Wi-Fi. The fire monitoring robot and the wireless communication of the fire receiving period are implemented and the effectiveness of the operation is confirmed through the field test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.569-581
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• 2016

The purpose of this study was to define the quality of nursing services in relation to a nurse's psychosocial factors (type A behavior pattern, self-esteem, locus of control, and anxiety), job stress, and fatigue. This study targeted 503 nurses currently working at one of six general hospitals in Daejeon city, the data were collected by a self-administered questionnaire, which was surveyed from April 1 to June 30, 2014. According to multivariate logistic regression analysis, the high self-esteem, locus of control, and strong support by supervisor and co-workers decrease the risk of a low career quality. In contrast, high situational fatigue and overall fatigue increase the risk of a low career quality. According to the results of hierarchical multiple regression analysis, the quality of nursing services increased with age, the subjective health condition was satisfying, aptitude corresponded to the jobs, self-esteem was high, anxiety was low, support by co-workers was strong, and the overall fatigue was low. Above results suggest that the quality of nursing services of nurses who work at a general hospital has a strong correlation with the psychosocial factors, job stress, and fatigue.

• Journal of Digital Convergence
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• v.13 no.3
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• pp.221-229
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• 2015

This study was performed to determine the occupational stress and its association with human nature factors, mental health factors and fatigue among some hospital administrative staff. The survey was administered to 189 staff in Jeonbuk area from June 1st to July 31th, 2014. The level of occupational stress was positively correlated with human nature, mental health and fatigue. The results of hierarchical multiple regression analysis show the following. The occupational stress of respondents turned out to be significantly higher in following groups: a group of female, a group that chance locus of control is higher, a group that external locus of control is lower, a group of the lower self-esteem, a group of higher situational fatigue, a group of higher psycho-social stress, and a group of higher depression. Their explanatory power was 60.4%. With the analysis of covariance structure, we could confirm relationship among the four factors such as human nature, mental health, fatigue and occupational stress. Also, the analysis showed that human nature factors were more influential on the occupational stress than mental health factors and fatigue.

• The KIPS Transactions:PartA
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• v.8A no.1
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• pp.16-26
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• 2001

This paper proposes an extended scheduler model that is an extension of the existing model proposed already in [4, 5], which consists of upper layer task scheduler and lower layer scheduling framework. However, in order to support aperiodic task scheduling, the task scheduler has been divided into two parts, such as periodic task control component and aperiodic task control component. Thus, the proposed model can support various bandwidth-preserving servers that can service aperiodic tasks. The model distinctly separates a classic monolithic kernel scheduler into several kernel components according to their functionality. This enables system developers to implement a new scheduling algorithm or aperiodic task server independent of complex low kernel mechanism, and reconfigure the system at need. In Real-Time Linux [6], we implemented the proposed scheduling framework representative scheduling algorithms, and server bandwidth-preserving servers on purpose to test. Throughout these implementations, we confirmed that a new algorithm or server could be developed independently without updates of complex low kernel modules. In order to verify efficiency of the proposed model, we measured the performance of several aperiodic task servers. The results showed this the performance of model, which even consisted of two hierarchical components and several modules, didnt have such high run-time overhead, and could efficiently support reconfiguration and scheduler development.

• Journal of Family Resource Management and Policy Review
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• v.21 no.4
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• pp.1-15
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• 2017

The purpose of this study was to identify the effect of satisfaction with the marriage support policy on marriage intention among unmarried employed men and women. The study subjects included 300 unmarried working men and women aged over 30 years residing in the Seoul metropolitan area. First, according to the analysis of the subjects' overall tendency towards satisfaction with the marriage support policy and towards marriage intention, the marriage support policy gained the highest level of support in relation to housing for newlywed couples, which scored 3.29 (sd=.93), followed by improvements in corporate and family culture for the purposes of work-family compatibility at 3.24 (sd=.95), wedding loans at 3.18 (sd=1.01), and the paid leave system for marriage preparation at 3.12 (sd=.88). These variables scored slightly higher than the median 3 points. Conversely, satisfaction with the availability of marriage-related information and the provision of opportunities for dating scored 2.65 (sd=.88) and 2.78 (sd=.80), respectively, both of which were slightly lower than the median of 3. The overall mean score for satisfaction with the marriage support policy was 3.03 (sd=.95), which was slightly higher than the median of 3. In regards to marriage intention, the score was 3.32 (sd=1.15) points out of a perfect score of 5, which was slightly higher than the median. This indicated a slightly higher level in terms of the subjects' intention to marry. Second, a hierarchical regression analysis was performed to identify the effect of satisfaction with the marriage support policy on marriage intention among unmarried employed adults. Sociodemographic variables were entered as control variables in the regression at the first stage, and variables relating to satisfaction in a family-friendly social environment were entered at the second stage. When gender, age, educational level, monthly income, period of employment, working hours, and type of employment were inserted in the first stage of regression as control variables, gender, monthly income, period of employment, and type of employment were found to have a significant effect on marriage intention. Marriage intention was found to be greater in unmarried men with higher monthly incomes and longer periods spent working, and in unmarried working men and women engaged in tenured employment work. When variables relating to satisfaction with the marriage support policy were inserted in the second stage of regression, gender, monthly income, type of employment, and satisfaction with direct marriage support had significant effects on marriage intention. It was found that marriage intention was greater in unmarried men whose monthly income was higher, whose employment type was tenured work, and who showed greater satisfaction with direct marriage support.

• Journal of Ecology and Environment
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• v.45 no.4
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• pp.277-286
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• 2021

Background: As trade increases, the influx of various alien species and their spread to new regions are prevalent and no longer a special problem. Anthropogenic activities and climate changes have made the distribution of alien species out of their native range common. As a result, alien species can be easily found anywhere, and they have nothing but only a few differences in intensity. The prevalent distribution of alien species adversely affects the ecosystem, and a strategic management plan must be established to control them effectively. To this end, hot spots and cold spots were analyzed according to the degree of distribution of invasive alien plants, and major environmental factors related to hot spots were found. We analyzed the 10,287 distribution points of 126 species of alien plants collected through the national survey of alien species by the hierarchical model of species communities (HMSC) framework. Results: The explanatory and fourfold cross-validation predictive power of the model were 0.91 and 0.75 as AUC values, respectively. The hot spots of invasive plants were found in the Seoul metropolitan area, Daegu metropolitan city, Chungcheongbuk-do Province, southwest shore, and Jeju island. Generally, the hot spots were found where the higher maximum temperature of summer, precipitation of winter, and road density are observed, but temperature seasonality, annual temperature range, precipitation of the summer, and distance to river and sea were negatively related to the hot spots. According to the model, the functional traits accounted for 55% of the variance explained by the environmental factors. The species with higher specific leaf areas were more found where temperature seasonality was low. Taller species preferred the bigger annual temperature range. The heavier seed mass was only preferred when the max temperature of summer exceeded 29 ℃. Conclusions: In this study, hot spots were places where 2.1 times more alien plants were distributed on average than non-hot spots (33.5 vs 15.7 species). The hot spots of invasive plants were expected to appear in less stressful climate conditions, such as low fluctuation of temperature and precipitation. Also, the disturbance by anthropogenic factors or water flow had positive influences on the hot spots. These results were consistent with the previous reports about the ruderal or competitive strategies of invasive plants instead of the stress-tolerant strategy. The functional traits are closely related to the ecological strategies of plants by shaping the response of species to various environmental filters, and our result confirmed this. Therefore, in order to effectively control alien plants, it is judged that the occurrence of disturbed sites in which alien plants can grow in large quantities is minimized, and the river management of waterfronts is required.

• Journal of Korea Entertainment Industry Association
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• v.14 no.2
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• pp.109-118
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• 2020

This study examines the relative usefulness of the TPB and Extended TPB with the addition of the "Battery" variable to participants in marine sports experiences. The characteristics of behavioral theories (attitude, subjective norms, perceived behavioral control, and revisit intention) were compared. A total of 420 questionnaires were distributed and surveyed using the convenience sampling method to the general public who participated in the marine sports experience in S city in 2019. Finally, 385 copies of valid samples were extracted, except for the questionnaire. The following analyzes were performed using SPSS 21.0 and AMOS 21.0. Frequency analysis, confirmatory factor analysis, concept reliability, AVE value, Cronbach's α correlation analysis, hierarchical regression analysis, and independent sample t-test were performed. First, in the TPB, three predictors were found to have a positive effect on revisit intention. Attitudes, subjective norms, and prior knowledge, except for behavioral control, were found to have a positive effect. Second, the explanatory power to explain the return intention was 51.8% (3.3% more than plan behavior theory, p = .000). It can be seen that when prior knowledge is added as a new variable, it is an important factor in explaining intention to return. Third, prior knowledge variables were classified into high and low groups to compare the characteristics of the extended planning behavior theory. The results of the analysis showed that the group with higher prior knowledge had a higher mean value for the constituent variables of the extended planning behavior theory.