• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.273-276
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• 2010

Opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.513-521
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• 2010

Most of universities have carried out course evaluation to apply the performance appraisal for professor. But, course evaluation depends on characteristics of each class such as class size, type of lecture, evaluator's grade and so on. As the results, such characteristics of each class lead to serious bias which makes lecturers distrust the course evaluation results. Hence, we propose a equating method for the course evaluation by regression analysis which use stepwise variable selection. And we compare proposed method with the other method by Cho et al. (2009) with respect to efficiencies. Also we give the example to which the method is applied.

• Journal of East-West Nursing Research
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• v.24 no.1
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• pp.63-69
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• 2018

Purpose: The purpose of this study was to investigate the factors related to the academic burden on weight loss efforts among adolescents aged 12-18 in Korea. Methods: This study analyzed 29,069 obese adolescents (10.8%) using raw data of the 9th~12th the Korea Youth Risk Behavior Web-based Survey collected from 2013 to 2016. The data was analyzed using descriptive statistics, Chi-square and multivariate logistic regression. Results: Weight control efforts were significantly higher among girls, middle school students, those who are participating in nutrition education, and individuals with perceived fatness or perceived stress. Additionally, a long sitting time and high academic performance were found to be variables affecting the weight control efforts of adolescents. Conclusion: Obese adolescents in Korea spent a lot of time in their studies due to their academic burdens and this caused a lack of time to adjust their weight. Therefore, it is needed to establish a policy by considering these social and cultural factors for obese adolescents in Korea.

• Journal of Korean Public Health Nursing
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• v.31 no.3
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• pp.464-477
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• 2017

Purpose: This study was conducted to investigate factors affecting the dementia screening test based on the health belief model. Methods: The survey was conducted with structured questionnaires assessing the knowledge of dementia, health beliefs, self-efficacy and cue to action for dementia screening. Study participants were 156 older adults and data from 121 respondents were analyzed. Descriptive statistics, frequency percentage, chi-squared (${\chi}^2$) test, t-test and logistic regression analysis were conducted using SPSS version 23.0. Results: Factors influencing the dementia screening test were found to be gender, self-efficacy on dementia screening, and the presence of family or friends who underwent dementia screening. Older adults who were female (OR=4.92, p=.003), showed an increasing average score of self-efficacy for dementia screening (OR=2.85, p=.002), and had family members or friends who underwent dementia screening (OR=4.60, p=.003) were more likely to receive dementia screening. Conclusion: This study showed that education and programs enhancing self-efficacy associated with the dementia screening test, as well as utilizing the network of family or friends are necessary to increase the rate of dementia screening.

• Journal of Korean Elementary Science Education
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• v.29 no.1
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• pp.47-55
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• 2010

This study was to examine science learning motivation of primary students participating in science museum educational programs. The subject was 36 primary students in the programs in a science museum during a month. The questionnaire for this study consisted of items developed by us and some items from Motivated Strategies for Learning Questionnaire developed by Pintrich et al.(2001). The results included primary students' motivation of joining the programs in a science museum, their perceptions about the programs, and the effects of the programs on their science learning motivation. It seemed that the students had the opportunities of doing science activities in the museum on the recommendation of their family or teachers, especially their parents. And they were motivated to participate the programs with interests of science and they were interested in the activities in the programs. The statistics showed that the program have an positive effects on the students' self efficacies and values on science tasks. Based on this results, discussion and implications were presented.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.72-80
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• 2016

Re-auction happens when a bid winner defaults on the payment without making second in-line purchase declaration even after determining sales permission. This is a process of selling under the court's authority. Re-auctioning contract price of real estate is largely influenced by the real estate business, real estate value, and the number of bidders. This paper is designed to establish a statistical model that deals with the number of bidders participating especially in apartment re-auctioning. For these, diverse factors are taken into consideration, including ratio of minimum sales value from the point of selling to re-auctioning, number of bidders at the time of selling, investment value of the real estate, and so forth. As an attempt to consider ambiguous and vague factors, this paper presents a comparatively vague concept of real estate and bidders as trapezoid fuzzy number. Two different methods based on the least squares estimation are applied to fuzzy regression model in this paper. The first method is the estimating method applying substitution after obtaining the estimators of regression coefficients, and the other method is to estimate directly from the estimating procedure without substitution. These methods are provided in application for re-auction data, and appropriate performance measure is also provided to compare the accuracies.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.2
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• pp.91-102
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• 2017

Backpack-mounted mapping system is firstly introduced for flexible movement in indoor spaces where satellite-based localization is not available. With the achieved advances in miniaturization and weight reduction, use of LiDAR (Light Detection and Ranging) sensors in mobile platforms has been increasing, and indeed, they have provided high-precision information on indoor environments and their surroundings. Previous research on the development of backpack-mounted mapping systems, has concentrated mostly on the improvement of data processing methods or algorithms, whereas practical system components have been determined empirically. Thus, in the present study, a simulator for a LiDAR sensor (Velodyne VLP-16), was developed for comparison of the effects of diverse conditions on the backpack system and its operation. The simulated data was analyzed by visual inspection and comparison of the data sets' statistics, which differed according to the LiDAR arrangement and moving speed. Also, the data was used as input to a point-cloud registration algorithm, ICP (Iterative Closest Point), to validate its applicability as pre-analysis data. In fact, the results indicated centimeter-level accuracy, thus demonstrating the potentials of simulation data to be utilized as a tool for performance comparison of pointdata processing methods.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.445-451
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• 2012

We developed an age-based spawner-recruit model incorporating environmental variables to forecast stock biomass and recruits of pelagic fish in this study. We applied the model to the Tsushima stock of jack mackerel, which is shared by Korea and Japan. The stock biomass of jack mackerel (Trachurus japonicus) around Korean waters ranged from 141 thousand metric tons (mt) and 728 thousand mt and recruits ranged from 27 thousand mt to 283 thousand mt. We hind-casted the stock biomass to evaluate the model performance and robustness for the period of 1987~2009. It was found that the model has been useful to forecast stock biomass and recruits for the period of the lifespan of fish species. The model is also capable of forecasting the long-term period, assuming a certain climatic regime.

• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.79-87
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• 2012

In the case that the probability density function has a discontinuity point, Huh (2002) estimated the location and jump size of the discontinuity point based on the difference between the right and left kernel density estimators using the one-sided kernel function. In this paper, we consider the cross-validation, made by the right and left maximum likelihood cross-validations, for the bandwidth selection in order to estimate the location and jump size of the discontinuity point. This method is motivated by the one-sided cross-validation of Hart and Yi (1998). The finite sample performance is illustrated by simulated example.

• Child Health Nursing Research
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• v.11 no.4
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• pp.436-443
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• 2005

Purpose: This study was done to explore the levels of depression experienced by adolescents, and to compare health behavior between depressed and non-depressed adolescents. Method: Participants were chosen by a stratified random sampling of adolescents in the second grade of a high school in P city. Levels of depression and health behavior of the students were measured using questionnaires. Data collection was done in May, 2002. Data were analyzed with descriptive statistics and logistic regression using the SPSS WIN 10.0 Program. Results: The prevalence of depression (CES-D) among the students was $53.5\%$. In multiple logistic regression analysis, sex (OR 1.80, $95\%$ Cl 1.35-2.41), school performance, mid (OR 1.68, $95\%$ Cl 1.48-1.97) and low (OR 1.42, $95\%$ Cl 1.29-1.61), drinking (OR 1.47, $95\%$ Cl 1.09-1.98), and not eating breakfast (OR 1.74, $95\%$ Cl 1.56-1.97) were significantly higher in students in the depressed group than those in the non-depressed group. Conclusions: Based on the findings, we concluded that many adolescent experience depression and depression in adolescents is significantly related to behaviors of smoking, alcohol, no exercise, and not eating breakfast. However this study did not address causality among these variables. There, further research, such as a longitudinal study, is needed to identify causality among the variables.