• Sleep Medicine and Psychophysiology
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• v.9 no.2
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• pp.115-121
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• 2002

Objectives: Although sleep paralysis (SP) has been known as one of the symptoms of narcolepsy, recently it has become recognized as occurring frequently in the general population. However, the prevalence of SP and its associated factors in patients with major psychiatric disorders remain unknown. This study investigated the prevalence of SP and a variety of associated experiences in those patients. Methods: The subjects were 160 psychiatric patients and 143 age- and sex-matched controls. The Korean version SP questionnaire as well as the Sleep-Wake Schedule, Epworth Sleepiness Scale and Insomnia Severity Index were administered to all the subjects. The patients were referred from Dong-A University Hospital and consisted of 74 diagnosed as schizophrenia (47.7%), 26 as bipolar disorder (16.8%) and 55 as major depression (35.5%). Results: Nearly 42% of the patient group and 39% of the control group had experienced at least one episode of SP in their lifetime, with no significant difference between the groups. However, the patient group had experienced SP more frequently than the control group. Among all subjects, no gender difference in SP incidence was found. The peak age of onset was in the range of 16-25 years for both groups. Over eight tenths of both groups reported hallucinations and over seven tenths of both groups experienced fear accompanying SP. Conclusion: This study shows that there is no difference in the lifetime prevalence of SP between psychiatric patients and the general population, whereas frequency of SP experience is higher in psychiatric patients. Terrifying hallucinations and fearful feelings frequently accompany SP in both groups.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.439-452
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• 2022

This study aimed to explore the relationships between random item usage and gaming disorder tendency. A total of 413 adults participated and demographic and psychosocial variables were collected using Cloninger's Temperament and Character Inventory, Cognitive Emotion Regulation Questionnaire, and Daily Hassles Scale for Korean Worker. The results are as follows. First, two-third of gamers used the random item games and women are more engaged than men in random item games. Second, there were significant differences of gaming disorder tendency, game use time, and game use money (both for general and random item) depending on the item use type. Third, predictors of gaming disorder tendency were found as game use money (general), game use time, maladaptive emotion regulation, stress, novelty seeking, and stress using multiple regression analysis. Proper intervention for gaming disorder tendency and the need of further research were discussed.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.995-1006
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• 2022

The purpose of this study was to investigate the current status of practical course operation in a non-face-to-face online environment, learning effects, and students' experiences and perceptions for radiology major students using a survey. The questionnaire consisted of a total of 34 items in 5 areas: general characteristics of subjects, current learning participation in non-face-to-face environments, learning satisfaction, learning outcomes, improvement and requirements. For the analysis of the questionnaire responses, frequency analysis was performed on the response frequency, ratio, and scale for each item. Based on the general characteristics of the survey respondents, cross-analysis was performed using the chi-square test for participation in non-face-to-face learning, learning performance, and learning satisfaction. implemented. Improvements and requirements were qualitatively analyzed for the repetition frequency of words with the same meaning. Through the results of analyzing the responses of a total of 397 questionnaires, the direction of design and development of practical classes in a non-face-to-face environment in the future and basic information and implications for efficient operation were confirmed. Based on this, it is necessary to continue to think and make efforts for the efficient operation of non-face-to-face practice classes in the post-corona era.

• Journal of the Korean Society of Radiology
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• v.83 no.4
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• pp.887-897
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• 2022

Purpose To evaluate the safety and efficacy of stent-assisted coil embolization (SAC) in acutely ruptured cerebral aneurysms without severe symptoms, and thus, the usefulness of the stent itself in patients with subarachnoid hemorrhages. Materials and Methods From January 2017 to June 2019, 118 patients were treated with coil embolization for acutely ruptured cerebral aneurysms without severe symptoms (Hunt & Hess grade ≤ 3). The periprocedural complications, six-month modified Rankin scores (mRS), and six-month radiologic outcomes were compared between 56 patients with SAC and 62 patients without SAC (non-SAC). Results The rate of good clinical outcomes (mRS ≤ 2), as well as the rate of hemorrhagic and ischemic complications, showed no significant difference between the SAC and non-SAC groups. Moreover, compared to the non-SAC group, the SAC group showed a lower recanalization rate on the six-month follow-up angiogram (20% vs. 39.3%, p = 0.001). Conclusion Although stent use was not significantly associated with clinical outcomes in coil embolization of ruptured cerebral aneurysms with non-severe symptoms (Hunt & Hess grade ≤ 3), it significantly decreased the rate of recanalization on follow-up cerebral angiograms.

• Sleep Medicine and Psychophysiology
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• v.13 no.2
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• pp.67-74
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• 2006

Introduction: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. Methods: Twelve narcoleptic patients (7 male, age: $22.9{\pm}2.6\;yrs$) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. Results: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. Discussion: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.

• Sleep Medicine and Psychophysiology
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• v.21 no.2
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• pp.61-68
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• 2014

Objective: The aim of the present study is to assess the prevalence and related risk factors of suicide ideation among middle and high school students in an urban area. Methods: We surveyed 3,691 middle and high school students (2,159 male, 1,532 female, 11-19 years of age) using a self-report questionnaire that covered basic socio-demographic data, academic achievements, presence of physical or psychiatric illness, sleep duration on weekdays, time spent at private academies on weekdays and weekends, and subjective needs for counseling. The Beck Depression Inventory (BDI) and Reynolds' Suicidal Ideation Questionnaire (SIQ) were included in the survey. Results: The prevalence of students with high suicide ideation ($SIQ{\geq}62$) was 4.6%. In a logistic regression model, female sex (p = 0.002), younger age (p < 0.001), poor academic achievement (p = 0.043) and higher score of BDI (p < 0.001) were associated with a higher SIQ score. In addition, younger age (p = 0.045) and a higher BDI score (p < 0.001) were associated with a higher SIQ score adolescents having high suicide ideation ($SIQ{\geq}62$). Conclusion: Related risk factors of suicide ideation in adolescents were female sex, younger age, poor academic achievement, and a depressive mood. It would be especially helpful to pay more attention to younger adolescents and a depressive mood as a high-risk group. The understanding of these factors will be helpful for providing an effective suicide screening and prevention program for adolescents.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1171-1180
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• 2015

Multidimensional scaling (MDS) is a graphical technique of multivariate analysis to display dissimilarities among individuals into low-dimensional space. We often have two kinds of MDS which are metric MDS and non-metric MDS. Metric MDS can be applied to quantitative data; however, we need additional information about variables because it only shows relationships among individuals. Gower (1992) proposed a method that can represent variable information using trajectories of the pseudo-points for quantitative variables on the metric MDS space. We will call his method a 'replacement method'. However, the trajectory can not be represented even though metric MDS can be applied to binary data when we apply his method to binary data. Therefore, we propose a method to represent information of binary variables using pseudo-points called a 'partition method'. The proposed method partitions pseudo-points, accounting both the rate of zeroes and ones. Our metric MDS using the proposed partition method can show the relationship between individuals and variables for binary data.

• Korean Journal of Psychosomatic Medicine
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• v.14 no.1
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• pp.47-52
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• 2006

Backgrounds : Depression has been prevalent in women and maintaining optimal glycemic control is an important goal of diabetes management. Although depression is common in adults with diabetes, its relationship to glycemic control remains unclear, espacilly in Korean women. The current study examined the relationship of depressive symptomatology with glycemic control in Korean women. Methods : Beck depression inventory (BDI), $HbA_{1c}$ as an index of long-term glycemic control, fasting glucose level and body mass index (BMI) were measured in sample of 4,567 women of whom 4.7%, 216 women had diabetes, and the relationship between depression and glycemic control was analyzed. BDI Scores of 16 and above is a cut off point to indicate possible clinical depression. Results The frequency of depressed women (p<0.001) and the mean score of BDI (p<0.001) were significantly higher in diabetic women. The mean level of $HbA_{1c}$ (p<0.01) and fasting glucose (p<0.05) were higher in depressed women. There was a graded relationship between the percentile of depressed women and a degree of glycemic control impairment (p=0.001). Conclusion : The current study found the relationship of depressive symptomatology with glycemic control in Korean women. This relationship may be mediated by decreased self-care behaviors or by neurobiological dysregulation. Improving identification and treatment of depression in women with diabetes might have favorable effects on diabetic outcomes.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.80-90
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• 2002

Clustering is a useful technique for grouping data points such that points within a single group/cluster have similar characteristics. Many clustering algorithms have been developed and used in engineering applications including pattern recognition and image processing etc. Recently, it has drawn increasing attention as one of important techniques in data mining. However, clustering algorithms such as K-means and Fuzzy C-means suffer from difficulties. Those are the needs to determine the number of clusters apriori and the clustering results depending on the initial set of clusters which fails to gain desirable results. In this paper, we propose a new clustering algorithm, which solves mentioned problems. In our method we use evolutionary algorithm to solve the local optima problem that clustering converges to an undesirable state starting with an inappropriate set of clusters. We also adopt a new measure that represents how well data are clustered. The measure is determined in terms of both intra-cluster dispersion and inter-cluster separability. Using the measure, in our method the number of clusters is automatically determined as the result of optimization process. And also, we combine heuristic that is problem-specific knowledge with a evolutionary algorithm to speed evolutionary algorithm search. We have experimented our algorithm with several sets of multi-dimensional data and it has been shown that one algorithm outperforms the existing algorithms.

• Korean Journal of Culture and Social Issue
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• v.27 no.4
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• pp.475-503
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• 2021

The purpose of this study is to clarify the constructs of emotion suppression and help understanding on the multidimensional nature of emotion suppression by classifying constructs for suppression according to the KMW model. Also, this study examined the gender differences of emotion suppression. For this purpose, 657 adult male and female subjects were evaluated for attitude toward emotions, and difficulty in emotional regulation, as well as depression, state anger and daily stress scale. As a result of the exploratory factor analysis on the scales related to the emotion suppression factors, the emotion suppression factors corresponding to each stage of the KMW model were found to be 'distraction against emotional information, 'difficulty in understanding and interpretation of emotions', 'emotion control beliefs', 'vulnerability on emotional expression beliefs'. Next, the study participants were classified by performing a cluster analysis based on each emotion suppression factor. As a result, four clusters were extracted and named 'emotional control belief cluster', 'emotional expression cluster', 'emotional attention failure cluster', and 'general emotional suppression cluster'. As a result of examining the average difference of male depression, depression, state anger, and daily stress for each group, significant differences were found in all dependent variables. As a result of examining whether there is a difference in the frequency of emotional suppression clusters according to gender, the frequency of emotional suppression clusters was high in men, and the ratio of emotional expression clusters was high in women. Finally, it was analyzed whether there was a gender difference in the effect of the emotional suppression cluster on psychosocial adaptation, and the implications were discussed based on the results of this study.