• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4A
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• pp.365-372
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• 2007

In IEEE 802.11b wireless network, stations synchronize themselves to the beacons periodically sent by the access point(AP) when they are running in low power mode. In case of missing beacon due to noise or traffic from neighboring wireless network stations must be awake until they get the next beacon, which causes energy consumption in stations. In this paper, we propose a scheme searching next beacon consuming little energy. The problems of missing beacon in low power mode of IEEE 802.11b wireless interface are described and a new method to reduce energy consumption is proposed. The proposed method is simulated with the network simulator, ns2, and compared with the low power mode of the IEEE 802.11b. The result measured in terms of station's wakeup time shows some enhancement in energy consumption when some errors occur in receiving frames.

• Journal of the Korean Society of School Health
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• v.22 no.1
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• pp.107-118
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• 2009

Purpose: The purpose of this study was to investigate usage of earplones, PCPs, and to give the basic data for adolescent's hearing health education. The study was a descriptive research about three factors affecting hearing loss; the knowledge and attitude about noise, the perception of hearing loss. Method: For research purposes, we conducted a questionnaire survey of 1,480 high school students in Suwon, from 27 October 2007 to 31 2007. Result: Most of the subjets used PCPs for 3-5 years, the average time of using earphones per day was 1-3 hours, awake hearing acuity decrease after using is the hearing acuity became worse some, PCPs type is MP3, use place house, listening contents ballade, disorder condition experience after using if the ear it is sick. The average of concern about hearing scored the highest 3.01${\pm}$0.54. The average of perceived susceptibility scored 3.04${\pm}$0.63 and the average of knowledge about noise scored 2.76${\pm}$0.46. The average of total knowledge and attitude about noise scored 2.93${\pm}$0.52. The average of discomfort of hearing loss(2.20${\pm}$0.63) scored higher than that fear of hearing loss(1.66${\pm}$0.30). The average of total perception of hearing loss scored 2.12${\pm}$0.67. Conclusion: At least in this study are shown in the youth earphone, PCPs used as a spare because of the seriousness of the issue, so as a result of these problems related to hearing about the youth campaign, through advertising or seriousness of the young people need them. In addition, countries also need to create policies and the support for health education, especially during the regular curriculum subjects on subjects that include teenagers in the earphone, PCPs due to problems with spare on the contents of the reservoir. The severity of hearing loss young people, prevention of hearing to protect the youth.

• Journal of Korean society of Dental Hygiene
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• v.19 no.2
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• pp.317-327
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• 2019

Objectives: This study aimed to evaluate the effects of occlusion patterns using the T-scan $III^{(R)}$ system and oral parafunctional behaviors on temporomandibular joint disorder (TMD) in female college students. Methods: A questionnaire survey assessed TMD symptoms and oral behavioral checklist (OBC) scores in 120 female college students in their early twenties. Occlusion was evaluated using the T-scan $III^{(R)}$ system. Logistic regression analysis was performed to investigate the relationship between occlusion and OBC scores based on patients' symptoms of TMD and to determine whether OBC scores were a predictor of TMD. Results: A total of 101 participants with an average age of 22 (${\pm}2.17$) years were included in the analysis. The reported symptoms of TMD were categorized as moderate (28.8%), slight (27.7%), severe (25.7%), and asymptomatic (17.8%). Occlusion was analyzed using the T-scan $III^{(R)}$ system, and the mean occlusion time was 0.42(${\pm}0.5$) seconds. The results of logistic regression analysis showed that the group that would 'clench or grind teeth' during sleep showed an odds ratio for TMD that was 8.9 times higher than that in the group without this behavior. The group that would 'hold, tighten, or tense muscles without clenching' while awake showed an odds ratio for TMD that was 21.3 times higher than that in the group without this behavior. Conclusions: We confirmed that oral parafunctional behavior affects TMD. Therefore, we would like to continue studying the diagnosis and treatment of TMD by evaluating occlusion patterns and related OBC scores.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.335-344
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• 2019

This study aimed to identify the effect of stress, smartphone addiction, Social support, and physiological index on quality of sleep (PSQI) and to investigate the affecting factors according to sex in highschool students. The data were collected from 210 subjects from February 6 to 16, 2018 using a structured self-report questionnaires and analyzed using descriptive statistics, t-test, ANOVA, and multiple regression with SPSS WIN Version 24.0. The quality of sleep was lower in female students than in male students. In multiple regression analysis, Awake time, School grades stress were significant predictors and explained 29.6% of quality of sleep for male students. In female students, Smart phone start age, School grades stress, Disability of daily living and Appraisal social support were significant predictors and explained 24.3% of quality of sleep. Therefore, it is expected to be used as basic data for the development of intervention programs that can solve the factors affecting the quality of sleep of adolescents, thereby helping the healthy development of youth.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.126-134
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• 2015

A sleep disorder is being recognized as one of the major health issues related to high levels of stress. At the same time, interests about quality of sleep are rapidly increasing. However, diagnosing sleep disorder is not a simple task because patients should undergo polysomnography test, which requires a long time and high cost. To solve this problem, an accelerometer embedded wrist-worn device is being considered as a simple and low cost solution. However, conventional methods determine a state of user to "sleep" or "wake" according to whether values of individual section's accelerometer data exceed a certain threshold or not. As a result, a high miss-classification rate is observed due to user's intermittent movements while sleeping and tiny movements while awake. In this paper, we propose a novel method that resolves the above problems by employing a dynamic classifier which evaluates a similarity between the neighboring data scores obtained from SVM classifier. A performance of the proposed method is evaluated using 50 data sets and its superiority is verified by achieving 88.9% accuracy, 88.9% sensitivity, and 88.5% specificity.

• The Journal of Internal Korean Medicine
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• v.29 no.4
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• pp.1011-1024
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• 2008

Objectives : The aim of this study was to assess the distribution of general characteristics and risk factors according to onset time in acute stroke patients. Methods : We studied hospitalized patients within 4 wks after the onset of stroke who were admitted to the Department of Internal Medicine at Kyunghee University Oriental Medical Hospital, Kyunghee University East-West Neo Medical Hospital, Kyungwon University Songpa Oriental Medical Hospital, Kyungwon University Incheon Oriental Medical Hospital, and Dongguk University Ilsan Oriental Medical Hospital from April 2007 to August 2008. The 24-hour day was divided into quartiles (6:00 to 12:00, 12:00 to 18:00, 18:00 to 24:00 and 24:00 to 6:00). We analyzed the general characteristics and risk factors according to onset time in acute stroke patients. Results : 468 subjects were included into the final analysis. 1. The most common time period for ischemic stroke onset was between 6:00 and 12:00. It demonstrated a 50% excess risk between 6:00 and 12:00. 2. On the demographic variables of the patients, the rate of hypertension was significantly higher from 18: 00 to 24: 00 than 24:00 to 6:00. 3. There was no significant difference of stroke type, Sasang constitution, or lifestyle between times. 4. According to the blood test, high density lipoprotein cholesterol was significantly higher at 24:00 to 6:00 and lower at 12:00 to 18:00 than other time-groups. 5. The patients diagnosed with metabolic syndrome were significantly more at 12:00 to 18:00 and fewer at 24:00 to 6:00. 6. Hypertension and coffee drinking showed close relationship with patients whose stroke occurred while awake in multivariate analysis. Conclusions : The above results showed that the overall tendency of acute stage cerebral infarction patients varied according to their onset time. These results can be utilized in the future as a basis material.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.176-189
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• 2008

The purpose of this study was to analyze self-regulation about changing heart rate and perceived arousal variation when actors start their performance. Object of this study were 5 actors who belong to the theater selected using the purposive sampling method. This study used a measuring instrument of heart rate to measure arousal status, used behavior observation paper to observe and record self-regulation behavior and executed personal consultation after ending performance. There was graph mad by variation transition which calculated average and standard deviation about variation of heart rate each time of performance. The results of this study were as follows. First, there were high variation of awake level that actor's heart rates were rising before starting performance and the most high level of arousal was from 20minutes to 5minutes before starting performance. Second, there were self-regulation behaviors appeared such as deep breathing, breath controling, self talking, talking with other actors, concentrating an script, going to toilet, smoking, checking closes before starting performance. Third, when performance start, actors used psychological self-regulational method such as relaxation, self concentration, confidence reinforcement, coping with state or accommodation for controling raised arousal status.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.513-519
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• 1999

Chloral hydrate is one of the most widely used sedative agents to control the difficult to treat young age group in the dental clinic. We are often frustrated to see the patient still awake and cry with agitation even after far more than the normal onset time. In such a case, the patient has to be rescheduled for another sedation visit with different agents and/or routes which greatly disappoints the guardians. This case report presents a sedative regimen that can possibly help the clinician complete scheduled treatment without postponement. We have tried sleep induction with Enflurane (1-1.5vol%) for 60 seconds to 37 patients of those who failed to respond properly to the dose(70mg/kg)of oral Chloral hydrate. The average age and weight of the patients was 34.3 months(22-43mo.) and 14.9kg(11-21kg) respectively. It is suggested that sleep induction with low dose Eflurane produced a stable state during dental treatment with respect to vital sign and behavior. Evidence of adverse effect was not detected or reported during and/or after the procedures.

• Sleep Medicine and Psychophysiology
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• v.1 no.1
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• pp.47-59
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• 1994

Objectives: The main purpose of this study was to investigate the possible differences in sleepiness, performance, and body temperature during the night between morning(M) and evening(E) type subjects. Methods: After a survey study, to verify the validity and reliability of the Korean translation of the Home' and $\ddot{O}stberg's$ Morningness-Eveningness Questionnaire(1976), 8 extreme M-type subjects(3males, 5 females) and 8 extreme E-type subjects(3 males, 5 females) were selected from the university student population who had participated in the survey study. All subjects underwent sleep latency test and a battery of performance tests at intervals of 2 hours through the night, from 23:00 to 07:00. Oral temperature of each subject was taken every hour from 21 : 00 to 8 : 00. Between the testing times, the experimenters ensured that subjects remained awake. Results: More profound sleepiness was found in the M-type compared to the E-type throughout the night, with significant differences in sleepiness occuring at 23:00 and 01:00 hours. Overall performance efficiency tended to be lower through, the night in the M-type than in the E-type on all tests. A difference in time of temperature minimum between the two types was not noteworthy. Rather, there appeared to be a substantial difference in temperature level during the declining phase, with the temperature of the M-type being lower than that of the E-type. Conclusions: These results indicate the existance of a temporal relationship between sleepiness, perfonnance and body temperature during night work. Since the M-type exhibited greater sleepiness and lower performance efficiency overnight than the E-type, it may be assumed that the E-type is more suitable for and tolerable to night work. There was some discussion of the limitations in generalizing these results together with some suggestions for future studies.

• Anxiety and mood
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• v.9 no.2
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• pp.128-134
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• 2013

Objective : As treatments for breast cancer require long period of time, the patients need continuous monitoring and management of their health related quality of life. The purpose of this preliminary study is to explore the utility of monitoring quality of life using a mobile phone based application, which was developed to enable the patients to report daily quality of life more efficiently. Methods : Department of psychiatry, breast cancer center and U-health team of Asan Medical Center collaborated in developing a mobile application titled 'DugunDugun'. Through the application, patients with breast cancer receiving neo-adjuvant chemotherapy could report on various questions about their daily quality of life. We extracted and explored the daily basis of the data of sleep duration, number of awake, sleep satisfaction, mood and anxiety from nine patients who reported on the questionnaire for more than a month. Results : The longitudinal data collected using our mobile application well represented the characteristics of individual sleep patterns and daily emotional changes. Most of the patients showed high daily variations in the scores of their quality of life while their averaged scores were similar among patients. The patient with highest daily variations in the subjective sleep quality and daily emotional change had highest score corresponding to moderate depression in Beck Depression Inventory (BDI). Conclusion : The results suggest that mobile application could be a useful tool for monitoring and collecting the daily quality of life in the patients with breast cancer. We expect that mobile application could facilitate early detection and proper intervention for the cancer patients at psychological crisis.