• Korean Journal of Biological Psychiatry
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• v.24 no.1
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• pp.26-31
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• 2017

Objectives A normal circadian rhythm of autonomic nervous system function stands for the daily change of sympathetic and parasympathetic modulation, which can be measured by heart rate variability (HRV). Generally, patients in the intensive care unit (ICU) are prone to sleep-wake cycle dysregulation, therefore, it may have an influence on the circadian rhythm of autonomic nervous system. This study was designed to interpret possible dysregulation of autonomic nervous system in ICU patients by using HRV. Methods HRV was assessed every 3 hours in 21 ICU patients during a 7-minute period. The statistical differences of HRV features between the morning (AM 6 : 00-PM 12 : 00), and the afternoon (PM 12 : 00-PM 18 : 00) periods were evaluated in time domain and frequency domain. Results Patients showed significantly increased normalized power of low frequencey (nLF), absolute power of low frequencey (LF)/absolute power of high frequencey (HF) in the afternoon period as compared to the morning period. However, normalized power of high frequency (nHF) was significantly decreased in the afternoon period. There was no statistically significant difference between the morning period and the afternoon period in the time domain analysis. Conclusions The increased sympathetic tone in the afternoon period supports possible dysregulation in the circadian rhythm of autonomic nervous system in ICU patients. Future studies can help to interpret the association between autonomic dysregulation and negative outcomes of ICU patients.

• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.101-114
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• 2023

Background: This study aimed to explore the overall perception of pit and fissure sealants and suggest methods to revitalize their current stagnation. Methods: To determine the social perception of the change in coverage policy for pit and fissure sealants, we categorized them into five time periods. The first period (December 1, 2009 to November 30, 2010), the second period (December 1, 2010 to September 30, 2012), the third period (October 1, 2012 to May 5, 2013), the fourth period (May 6, 2013 to September 30, 2017), and the fifth period (October 1, 2017 to December 31, 2022). We utilized text mining, an unstructured big data analysis method. Keywords were collected and analyzed using Textom, and the frequency analysis of the top 30 keywords, structural features of the semantic network, centrality analysis, QAP correlation analysis, and co-occurrence analysis were conducted. Results: The frequency analysis showed that the top keywords for each time period were 'Cavities', 'Treatment', and 'Children'. In the structural features of the semantic network of pit and fissure sealants by time period, the density index was found to be around 1.00 for all time periods. The QAP correlation analysis showed the highest correlation between the first and second periods and the fourth and fifth periods with a correlation coefficient of 0.834. The co-occurrence analysis showed that 'cavities' and 'prevention were the top two words across all time periods. Conclusion: This study showed that pit and fissure sealants are well accepted by the society as a preventive treatment for caries. However, the awareness of health education related to these sealants was found to be low. Efforts to revitalize stagnant pit and fissure sealants need to be strengthened with effective education.

• Journal of Korea Water Resources Association
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• v.34 no.1
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• pp.81-90
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• 2001

A dynamic flood frequency analysis model was proposed for the frequency analysis in ungaged catchment and applied to 6 subbasins in Pyungchang River basin. As the dynamic flood frequency model requires precipitation, rainfall loss system, and runoff analysis, we adopt the rectangular pulse model, the SCS formula, and the geomorphoclimatic IUH(GcIUH) for the application. Input data for the analysis was borrowed from the results of the statistical flood frequency analysis using L-moment method for the same catchment, and then the return period was estimated using the model. This result was also compared with the return period estimated from the statistical analysis. By comparing with the results from two cases, we found the dynamic flood frequency analysis gave higher estimates than those from statistical analysis for the whole subbasins. However, the dynamic flood frequency analysis model has a potential to be used for determining the design flood for small hydraulic structure in ungaged catchment because it uses only physical parameters for flood frequency analysis. And this model can be easily applicable to other watersheds as the scale effect is negligible.

• Journal of Climate Change Research
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• v.9 no.4
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• pp.461-470
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• 2018

The frequency of extreme weather events was analyzed using meteorological data (air temperature, precipitation, and duration of sunshine) collected from 61 stations over a 36-year span (1981-2016). The 10-day meteorological data were used as a basic unit for this analysis. On average, the frequency of occurrence of abnormal weather was 9.88 per year and has increased significantly during this 36-year period. According to the type of abnormal weather, the frequencies of occurrence of abnormally high air temperature and short duration of sunshine have increased by 0.50 and 0.41 per 10 years, respectively; however, that for abnormally low air temperature has decreased by 0.31 per 10 years and the trend was statistically significant. The highest frequency of abnormal weather appeared in 2007, with a frequency of 14.31. Abnormal weather was the most frequent at Yeongdeok station with an average frequency of 11.78 per year over this 36-year span.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.67-76
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• 2009

Recently, the active interaction control (AIC) system was proposed as a semi-active control system. The AIC system consists of a primary structure and an auxiliary structure. The objective of the AIC system is to control the response of the primary structure through engagement and disengagement between the primary and auxiliary structures. Previous switching control algorithms have been shown to be effective in reducing the response of the primary structure. However, they have the main drawback of requiring an excessive engagement-disengagement frequency and high interaction force. In this paper, the regions in which the switching is activated and the regions in which the switching is deactivated are described separately, to effectively determine the engagement or the disengagement. The general relationship between the switching regions and the deactivated switching regions selected according to the engagement-disengagement conditions is described within the newly-developed comprehensive switching framework. The proposed engagement-disengagement conditions are designed within a comprehensive switching framework, to reduce engagement-disengagement frequency and interaction force. Furthermore, the effect of a control sampling period on the AIC system is explained in terms of the engagement-disengagement frequency. The effectiveness of the proposed algorithms and the effect of the control sampling period are considered for a single degree of freedom model under free vibration. It is observed that increasing the duration of stay by using a large control sampling period prevents the AIC system from activating the possible chance of switching. The proposed algorithms are shown to be effective, both in restricting ineffective switching and in reducing interaction force.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.14-26
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• 2021

Increase of climate variability due to climate change has paved the way for regional drought monitoring and outlook. In particular, Gimcheon-si, Gyeongsangbuk-do, is suffering from frequent and periodic drought damage as the frequency and magnitude of drought are increasing due to climate change. For this reason, it is necessary to analyze drought characteristics for sub-districts based on water district and calculate the basic low-flow considering climate change. In this study, meteorological and hydrological drought outlook were carried out for 8 sub-districts considering the water supply system and regional characteristics of Gimcheon-si according to various climate change scenarios. In addition, the low-flow frequency analysis for the near future was also performed using the total amount of runoff and the low-flow. The overall results indicated that, meteorological droughts were found to be dangerous in the S0(1974~2019) period and hydrological droughts would be dangerous in the S2(2041~2070) period for RCP 4.5 and in S3(2071~2099) period for RCP 8.5. The results of low-flow frequency analysis indicated that future runoff would increase but drought magnitude and frequency would increase further. The results and methodology may be useful for preparing local governments' drought measures and design standards for local water resources facilities.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.230-237
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• 2022

The Community Social Service Investment project started as a state subsidy project in 2007 and has grown very rapidly in quantitative terms in a short period of time. It is a bottom-up project that discovers the welfare needs of people and plans and provides services suitable for them. The purpose of this study is to analyze using big data to determine the social response to local community service investment projects. For this, data was collected and analyzed by crawling with a specific keyword of community service investment project on Google and Naver sites. As for the analysis contents, monthly search volume, related keywords, monthly search volume, search rate by age, and gender search rate were conducted. As a result, 10 items were found as related keywords in Google, and 3 items were found in Naver. The overall results of Google and Naver sites were slightly different, but they increased and decreased at almost the same time. Therefore, it can be seen that the community service investment project continues to attract users' interest.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.1019-1022
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• 2005

As recent information communication technology is rapidly developed, a lot of researches related to speech signal processing have been processed. So pitch period is applied as important factor to many application fields such as speech recognition, speaker identification, speech analysis and synthesis. Therefore, many algorithms related to pitch detection have been proposed in time domain and frequency domain and AMDF(average magnitude difference function) which is one of pitch detection algorithms in time domain chooses time interval from valley to valley as pitch period. But, in selection of valley point to detect pitch period, complexity of the algorithm is increased. So in this paper we proposed pitch detection algorithm using rotation transform of AMDF, that taking the global minimum valley point as pitch period and established a threshold about the phoneme in beginning portion, to exclude pitch period selection. and compared existing methods with proposed method through simulation.

• Journal of Korean Academy of Nursing
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• v.39 no.1
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• pp.62-71
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• 2009

Purpose: The purpose of this study was to explore the effects of listening to music in inpatients diagnosed with schizophrenia, on their auditory hallucinations, and positive and negative symptoms. Methods: A quasi-experimental research design with $2{\times}2$ cross-over trial and convenience sample was used. Eleven patients (Group AB) listened to music followed by a wash out period and then a usual care period, and 12 patients (Group BA) had a usual care period followed by a wash out period and then listened to music. For one week those who were in the experimental period listened to individualized music using an MP3 player whenever they heard hallucinations. Results: There was a statistically significant decrease in the frequency of auditory hallucinations after listening to the music. There was a decrease in the mean scores for positive symptoms, negative symptoms, and general psychopathology after listening to music, but only negative symptoms showed a statistically significant decrease. The treatment effects on scores for positive symptoms, negative symptoms, and general psychopathology were greater in Group BA than Group AB. Conclusion: These findings suggest that listening to music may be useful for managing auditory hallucinations in schizophrenia inpatients.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1015-1018
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• 2004

We proposed a new cross-coupled level shifter circuit using low temperature poly-Si(LTPS) TFT. The proposed level shifter can operate on low input voltage in spite of low mobility and widely varying high threshold voltage of LTPS TFT. Also, the proposed level shifter operates at high frequency and reduces power consumption for having fast rising and falling time and shortening period flowing short-circuit currents.