• Sleep Medicine and Psychophysiology
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• v.14 no.1
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• pp.42-48
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• 2007

Introduction: Detrended fluctuation analysis (DFA) is used as a way of studying nonlinearity of EEG. In this study, DFA is applied on sleep EEG of normal subjects to look into its nonlinearity in terms of EEG channels and sleep stages. Method: Twelve healthy young subjects (age：$23.8{\pm}2.5$ years old, male：female=7：5) have undergone nocturnal polysomnography (nPSG). EEG from nPSG was classified in terms of its channels and sleep stages and was analyzed by DFA. Scaling exponents (SEs) yielded by DFA were compared using linear mixed model analysis. Results: Scaling exponents (SEs) of sleep EEG were distributed around 1 showing long term temporal correlation and self-similarity. SE of C3 channel was bigger than that of O1 channel. As sleep stage progressed from stage 1 to slow wave sleep, SE increased accordingly. SE of stage REM sleep did not show significant difference when compared with that of stage 1 sleep. Conclusion: SEs of Normal sleep EEG showed nonlinear characteristic with scale-free fluctuation, long-range temporal correlation, self-similarity and self-organized criticality. SE from DFA differentiated sleep stages and EEG channels. It can be a useful tool in the research with sleep EEG.

• The Journal of Bigdata
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• v.1 no.1
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• pp.67-75
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• 2016

The study analyzed big data extracted from Google and social media to identify factors related to searches on cyber bullying in Korea and America. Korea's cyber bullying analysis was conducted social big data collected from online news sites, blogs, $caf{\acute{e}}s$, social network services and message for between January 1, 2011 and March 31, 2013. Google search trends for the search words of stress, exercise, drinking, and cyber bullying were obtained for January 1, 2004 and December 22, 2013. The main results of this study were as follows: first, the significant factors stress were cyber bullying that Korea more than America. Secondly, a positive relationship was found between stress and drinking, exercise and cyber bullying both Korea and America. Thirdly, significant differences were found all path both Korea and America. The study shows that both adults and teenagers are influenced in Korea. We need to develop online application that if cyber bullying behavior was predicted can intervene in real time because these actual cyber bullying-related exposure to psychological and behavioral characteristic.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.14 no.1
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• pp.123-127
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• 2003

Cornelia de Lange syndrome is a dysmorphogenic disorder characterized by multiple congenital abnormalities, mental retardation, growth retardation and neurodevelopmental abnormalities. Diagnosis for the Cornelia de Lange syndrome is dependent on the clinical observation because neither definite biological marker nor definite chromosomal abnormality have been investigated. Clinical observation is important for the diagnosis, so we report a case of Corenelia de Lange syndrome with mental retardation and autistic disorder. The patient is a 6-year old girl. Her motor development and language development have been delayed. She could say no meaningful word and understood simple command partially. She showed poor eye contact and poor emotional interaction. Social interaction was impaired and she Showed stereotypic behaviors. Thus we diagnosed her as mental retardation with autistic disorder. She had vesicoureteral reflux, frequent upper respiratory infection and pneumonia. She had experienced febrile convulsions 4 times. She had short stature, confluent eyebrows, long eyelashes, and upturned nose with anteverted nostrils. She also showed low hairline and hypertrichosis in body and extremities. Her finger was short. In this case, we diagnosed Cornelia de Lange syndrome by her characteristic face, hypertrichosis and medical and behavioral problems that were frequently showed in this syndrome.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.635-650
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• 2018

Many people have been recognized that the Korean Peninsula is no longer safe area from the earthquake by the recent earthquakes occurred in the country. The earthquakes that occurred at Pohang and Gyeongju appeared differently from them considered in the seismic design and researches on the seismic design method have been also conducted by many researchers. Studies on seismic loads are mainly focused on existing superstructures, and research involving them has been actively carried out in reality. However, paper regarding structural stability of reinforcement from seismic load such as soil-nails, rock-bolts, ground anchors which were constructed to ensure stability of serviced structure have been published rarely. In this study, ground anchor been effected by static load and seismic load which is settled in the weathered rock is analyzed. Results for static load are obtained from field test and seismic load is from numerical analysis. In this study, the behavioral characteristics of the ground anchor were analyzed by numerical analysis in case of seismic loading based on the result of the in-situ tensile test of the ground anchor settled weathered rock. As a result, settlement of concrete block due to application of tension force for ground anchor occurred as well as following loss of axial force for ground anchor. Also, as bond length and period of seismic load are longer, increasement of displacement is greater.

• Investigative Magnetic Resonance Imaging
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• v.25 no.3
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• pp.164-171
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• 2021

Purpose: Mild cognitive impairment (MCI) is a prodromal stage of Alzheimer's disease (AD). Brain atrophy in this disease spectrum begins in the medial temporal lobe structure, which can be recognized by magnetic resonance imaging. To overcome the unsatisfactory inter-observer reliability of visual evaluation, quantitative brain volumetry has been developed and widely investigated for the diagnosis of MCI and AD. The aim of this study was to assess the prediction accuracy of quantitative brain volumetry using a fully automated segmentation software package, NeuroQuant^®, for the diagnosis of MCI. Materials and Methods: A total of 418 subjects from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's Disease cohort were included in our study. Each participant was allocated to either a cognitively normal old group (n = 285) or an MCI group (n = 133). Brain volumetric data were obtained from T1-weighted images using the NeuroQuant software package. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to investigate relevant brain regions and their prediction accuracies. Results: Multivariate logistic regression analysis revealed that normative percentiles of the hippocampus (P < 0.001), amygdala (P = 0.003), frontal lobe (P = 0.049), medial parietal lobe (P = 0.023), and third ventricle (P = 0.012) were independent predictive factors for MCI. In ROC analysis, normative percentiles of the hippocampus and amygdala showed fair accuracies in the diagnosis of MCI (area under the curve: 0.739 and 0.727, respectively). Conclusion: Normative percentiles of the hippocampus and amygdala provided by the fully automated segmentation software could be used for screening MCI with a reasonable post-processing time. This information might help us interpret structural MRI in patients with cognitive impairment.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.181-199
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• 2021

Recently, financial companies are promoting chatbot services in line with the reduction of branches and the expansion of non-face-to-face services. However, it is difficult to expand the chatbot services at once in the presence of technical limitations and constraints of internal and external environment. Therefore, it is necessary to analyze the various situations of chatbot service to preemptively identify problems that can occur in stages and seek solutions. This study conducted interviews with 12 field practitioners and researchers to examine the intentions and behaviors of financial chatbot service users and interpreted them using TPB. The study revealed the characteristics of 'feelings and attitudes' such as convenience or inconvenience from the chatbot experience, 'subjective norms' such as herd behavior or the yearning for empathy of others, and 'behavioral control' according to the recognition of difficulty or convenience of chatbot use process. This study shows that this characteristic can affect the intention and actual behavior of users to use chatbot service continuously. In the future research, it is necessary to empirically study specific intentions and influence factors for actual users.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.328-338
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• 2022

This study aims to identify the influential relationship between the characteristics of tourism information of the MZ generation's SNS content, tourist destination reputation, and intentions of traveling behavior with a focus on Jeju Province. To achieve the purpose of this research, this study was conducted on 270 tourists who had recently traveled to Jeju Island after being exposed to characteristic tourism information on SNS within the last year among the MZ generation through a commissioned survey company. A total of 270 results were collected and used for empirical analysis. The results of the research are as follows. First, it was found that the reliability, usefulness, timeliness, and interactivity factors of SNS tourism information had a significantly positive (+) effect on the reputation of the tourist destination. Second, it was found that the reliability, usefulness, timeliness, and interactivity factors of SNS tourism information had a significantly positive (+) effect on the intentions of traveling behavior. Third, it was found that the tourist destination reputation has a positive (+) effect on the intentions of traveling behavior. This study discussed the future tourist destination reputation formation and future behavioral decision process of the MZ generation tourists who are constantly seeking tourist destinations. In addition, the theoretical implications presented in this study were discussed.

• Korean Journal of Culture and Social Issue
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• v.12 no.3
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• pp.49-68
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• 2006

The present study was attempted to compare duality in value structure and judgment system between youth, adults and North Korean defectors. A questionnaire was administered to 150 college students(Men: 89, Women: 61), 155 adults(Men: 80, Women: 75) and 80 North Korean defectors(Men: 39, Women: 41). Participants rated their values, behavior and South Korean behavior (or North Korean behavior for North Korean defectors) as a whole both on the 7 dimensions relevant to characteristics indigenous to Korean society and on their opposite 7 dimensions characteristic of Western culture. Results indicated that defectors marked the highest score on the traditional value dimensions, and yet youth ranked the first for the western value systems. Also, duality in value systems was the most severe for the defectors. In relation to dual judgement system in behavior, both young and old generation judged Korean behavior more negatively than their own. This was also the case for the North Korean defectors. Those findings were discussed in terms of cultural changes in Korean society.

• Information Systems Review
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• v.25 no.1
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• pp.111-128
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• 2023

With the development of artificial intelligence technology, interest in data-based product preference estimation and personalized recommender systems is increasing. However, if the recommendation is not suitable, there is a risk that it may reduce the purchase intention of the customer and even extend to a huge financial loss due to the characteristics of the financial product. Therefore, developing a recommender system that comprehensively reflects customer characteristics and product preferences is very important for business performance creation and response to compliance issues. In the case of financial products, product preference is clearly divided according to individual investment propensity and risk aversion, so it is necessary to provide customized recommendation service by utilizing accumulated customer data. In addition to using these customer behavioral characteristics and transaction history data, we intend to solve the cold-start problem of the recommender system, including customer demographic information, asset information, and stock holding information. Therefore, this study found that the model proposed deep learning-based collaborative filtering by deriving customer latent preferences through characteristic information such as customer investment propensity, transaction history, and financial product information based on customer transaction log records was the best. Based on the customer's financial investment mechanism, this study is meaningful in developing a service that recommends a high-priority group by establishing a recommendation model that derives expected preferences for untraded financial products through financial product transaction data.

• The Journal of Korean Academy of Sensory Integration
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• v.9 no.2
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• pp.41-49
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• 2011

Objective : This study aims to compare children with and without pervasive developmental disorders in terms of the sensory processing ability and behavioral characteristic of oral feeding. This study also aims to identify correlation between sensory processing and characteristics of eating. Methods : The subjects of this research were normal children and those who have diagnosis of a pervasive developmental disorder, aged from 4 to 6. The research instruments were composed of Short Sensory Profile (SSP), Brief Autism Mealtime Behavior Inventory (BAMBI) and Food Items of the Sensory Checklist. Data collection was done by a professional survey institute located in 10 cities including Busan, South Korea. The survey questionnaires were distributed to 455 parents of children with and without pervasive developmental disabilities through the survey institutes. Total 263 answers were collected out of 455 questionnaires (62%) and 154 answers were used in data analysis. Out of 154 answers, 45 were for children with pervasive developmental disabilities and 109 were for normal children. Data analysis was done to identify correlations between sensory processing and characteristics of eating such as eating behavior and oral feeding. Results : 1. There was a significant difference between children with and without pervasive developmental disorders in all area of sensory processing ability (p<.05). 2. There was no difference between children with and without pervasive developmental disorders in eating behavior (p=0.881) and oral feeding (p=0.324). 3. In the group of children with a pervasive developmental disorders, it is found that there is negative correlation between sensory processing, eating behavior and oral feeding (r=-0.384, p<.01). 4. A remarkable significant correlation was found between sensory processing and eating behavior especially in taste/smell sensitivity (r=-0.6, p<.01) and auditory filtering (r=-0.326, p<.05). The correlation between sensory processing and oral feeding was most significant in under responsiveness/seeking sensation (r=-0.372, p<.05) and auditory filtering (r=-0.382, p<.05). Conclusion : This study found that there are significant correlations between sensory processing ability and some characteristics of eating behaviors for children with pervasive developmental disorders. This information can be useful to develop a program to intervene eating behavior problems of children with pervasive developmental disorders.