• 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.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.64-65
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• 2005

Members of the Pumilio are the RNA binding proteins acting as translational repressors and required for germ cell development and asymmetric division. We identified chicken Pum1 and Pum2 that are similar to mouse and human in highly conserved C-terminal RNA-binding domain and eight tandem repeats. The comparative sequence analysis of Pum1 and Pum2 from fly, chicken, mouse and human shows high degree of evolutionary conservation in the homology of the peptide sequence and the structure of PUM-HD (Pumilio homology domain) with similar spacing between adjacent Pum repeats. Also, structures of chicken Pum1 and Pum2 genes are almost identical to those of mouse and human. We revealed that the expression levels of Pum1 and Pum2 were the highest in hatched female gonad among various embryonic tissues, and Pum2 expressed highly in 12-day and hatched gonad by real-time RT-PCR. These results suggest that Pum1 and Pum2 might have an effect on the development of chicken gonad.

• The Korean Journal of Emergency Medical Services
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• v.13 no.2
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• pp.61-72
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• 2009

Purpose : This study aimed to analyze the posttraumatic stress research trends in Korean and foreign firefighters. Method : Total 63 published international articles were searched by Pub Med internet site and total 17 published Korean articles were searched by Korean Medical Database internet site using 'PTSD in firefighters'. These articles were analyzed by published time, domains of journal, research designs, key words and research subjects. Result : 1) By the published time, there were 29 disaster-related researches(46.0%) and 34 job-related researches(54.0%) among 63 international articles. However, there were 16 disaster-related researches(94.1%) and 1 job-related research (5.9%) of Korean 17 articles. 2) By the international research domain, 9 researches(14.3%) were published in The Journal of Nervous and Mental Disease. Among domestic research domain, there were 9 researches(52.9%) consisting of 6 master's degrees and 3 doctor degrees. In major analysis of Korean domain, the highest portion is 4 psychology researches. (23.5%) 3) In the term of the international research design, quantitative research methods were highly used in both 23 disaster-related researches (36.5%) and 30 job-related researches(47.5%). In domestic research, quantitative research methods were mostly used in 14 job-related researches(82.3%) and Q methodology was only used in 1 disaster-related research(5.9%). 4) Looking on the research content trends according to the key words, 9 researches (31.0%) done on posttraumatic stress and coping had the most research and was followed up by posttraumatic stress symptom. Among these researches, key words for PTSD(Posttraumatic Stress Disorder) and PTS(Posttraumatic Stress) were mostly used. Moreover, there was 1 domestic study done on verifying the trends of Posttraumatic Stress in disaster-related research with PTS as the key word. In job-related research, the relationship between the Posttraumatic Stress and other factors had the most with ten studies (62.5%). Among these researches, key words for 5 PTSD(31.3%) were mostly used. 5) According to the international research subjects, the Posttrau consist the most subjects with 16 cases each for disaster and job related stress ; however, domestic research had 16 studies(94.1%) only using firefighters and 1 (5.9%) with their families as subjects. Conclusion : Although the studies of Posttraumatic Stress on Korean firefighters had started later than those on Foreign firefighters, first used for crucial topics show research development in various fields of study and should be tested for studies like those done in abroad regarding multiple topics and methods.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.155-161
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• 2010

Recently, the electromagnetic techniques of the eddy current testing(ECT), alternating current field testing, magnetic flux leakage testing and remote field testing have been used as a nondestructive evaluation method based on the electromagnetic induction. The eddy current testing is now widely accepted as a NDE method for the heat exchanger tube in the electric power industry, chemical, shipbuilding, and military. The ECT system mainly consists of the synthesizer module, analog module, analog-to-digital converter, power supplier, and data acquisition and analysis program. In this study, the synthesizer module and the analog module which are essential to the ECT system were primarily developed. The developed ECT system is basically a multifrequency type which is able to inject the maximum four frequencies based on the frequency and time domain multiplexing method. Conclusively, we confirmed that the EC signal was processed appropriately in each circuit modules, and the Lissajous EC signal was displayed in the impedance plane.

• Journal of Sensor Science and Technology
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• v.29 no.4
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• pp.249-254
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• 2020

It is difficult to control children who exhibit negative behavior in dental clinics. Various methods are used for preventing pediatric dental patients from being afraid and for eliminating the factors that cause psychological anxiety. However, when it is difficult to apply this routine behavioral control technique, sedation therapy is used to provide quality treatment. When the sleep anesthesia treatment is performed at the dentist's clinic, it is challenging to identify emergencies using the current breath detection method. When a dentist treats a patient that is under the influence of an anesthetic, the patient is unconscious and cannot immediately respond, even if the airway is blocked, which can cause unstable breathing or even death in severe cases. During emergencies, respiratory instability is not easily detected with first aid using conventional methods owing to time lag or noise from medical devices. Therefore, abnormal breathing needs to be evaluated in real-time using an intuitive method. In this paper, we propose a method for identifying abnormal breathing in real-time using an intuitive method. Respiration signals were measured using a 3M Littman electronic stethoscope when the patient's posture was supine. The characteristics of the signals were analyzed by applying the signal processing theory to distinguish abnormal breathing from normal breathing. By applying a short-time Fourier transform to the respiratory signals, the frequency range for each patient was found to be different, and the frequency of abnormal breathing was distributed across a broader range than that of normal breathing. From the wavelet transform, time-frequency information could be identified simultaneously, and the change in the amplitude with the time could also be determined. When the difference between the amplitude of normal breathing and abnormal breathing in the time domain was very large, abnormal breathing could be identified.

• Sleep Medicine and Psychophysiology
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• v.19 no.1
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• pp.27-34
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• 2012

Objectives: The analysis of heart rate variability (HRV) is a useful non-invasive tool to investigate the autonomic nerve function. Previous studies on the relationship between HRV and depression have been reported controversial results. Similarly, the correlation between the serum lipids and depression is debatable. The purpose of this study is to examine the relationship between heart rate variability, lipid profile and depression. Methods: A total of 42 patients with major depressive disorder (MDD) and 32 age and sex-matched normal subjects who had no previous history of major medical and mental illnesses were recruited for this study. A structured-interview was used to assess the general characteristics and psychiatric illness. HRV measures were assessed by time-domain and frequency-domain analyses. Psychological symptoms were measured using the Hamilton rating scale for anxiety (HAM-A), Hamilton rating scale for depression (HAM-D). In addition, the evaluation for lipid profile was performed by blood test. Results: In serum lipid profile test, MDD group showed higher cholesterol ($197.68{\pm}42.94$ mg/dL vs. $176.85{\pm}34.68$ mg/dL, p=0.044), TG ($139.45{\pm}92.54$ mg/dL vs. $91.4{\pm}65.68$ mg/dL, p=0.018), LDL ($130.03{\pm}33.18$ vs. $106.62{\pm}27.08$, p=0.004) level than normal control group. In HRV time domain analyses, the standard deviation of the NN interval (SDNN) was decreased in MDD group than normal control group, but was not significant ($32.82{\pm}14.33$ ms vs. $40.36{\pm}21.40$ms, p=0.078). ApEn (Approximate Entrophy) was significantly increased in MDD group than normal control group ($1.13{\pm}0.11$ vs. $0.91{\pm}0.18$, p<0.001). ApEn was correlated with LDL level (r=0.277, p=0.028), HAM-D scores (r=0.534, p<0.001) and HAM-A scores (r=0.470, p<0.001). Conclusions: MDD patients showed increased ApEn, one of the HRV measurement. And this ApEn was correlated with LDL, HAM-D and HAM-A scores. In this study, the analysis of ApEn would be a useful test of MDD.

• 대한공업교육학회지
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• v.32 no.2
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• pp.23-46
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• 2007

The purpose of this study was to present improvement directions of college scholastic ability test on industry department. Industry department test were classify and abstracted sampling test on contents and movement domain, analyzed example items of college scholastic ability test on industry department. Research methods used in this study were review of related literature, the item analysis and item pattern analysis between college scholastic ability test on introduction to industry and curriculum, contents of textbook. After finding a problem of developing items, trying to find a solution to the problem and developing an up-to-date method of items was to present improvement. Based on the result of the study, some recommendations for future researches were made as follows: First, a phenomenon of making same contents items over again and no making items not on made the items ever have to cut. Second, Time to read and make sense of items have to reduce because depend on the degree of difficulty related on time to understand of items. Third, the depth of textbook contents has to develop on curriculum this year. Fourth, the succeeding study on linkage between college scholastic ability test and simulation of college scholastic ability test. Fifth, verification validity on contents of new movement domain is developed new and striking test items.

• Korean Journal of Psychosomatic Medicine
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• v.21 no.1
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• pp.55-61
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• 2013

Objectives : Alzheimer's disease(AD) and mild cognitive impairment(MCI) affect several nervous structures involved with the autonomic nervous system. Association between neuropsychiatric deficits and heart rate variability has been observed. But cardiac autonomic function in AD has been scarcely studied and the results reported are conflicting. We investigated autonomic function in normal control, MCI, AD using heart rate variability(HRV) technique. Methods : Time and frequency-domain variability of 5-min R-R interval series was comparatively evaluated in 26 normal control subjects, 22 MCI subjects and 34 AD subjects. Analysis of variance(ANOVA) was used to compare the differences across groups. Correlations between MMSE-KC and HRV components were performed using Pearson's correlation coefficient. Results : No significant difference was observed among the groups in time, frequency-domain analysis of HRV(p>0.05). HRV were not found to be significantly correlated with the degree of cognitive impairment. Conclusions : There were no differences in HRV with MCI, AD subjects when compared with normal controls. Further investigation is required to use HRV technique as noninvasive parameters of MCI and AD.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.127-138
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• 1996

The strip method, unified theory and 3-D panel method are commonly used methods for the seakeeping analysis of high-speed vessels. The strip method which is basically 2-dimensional method is known to give incorrect hydrodynamic coefficients and motion responses for the cases of high speed and low frequency region. And the unified theory which uses two dimensional approach in inner domain and slender body theory in outer domain is very complicate in computational modelling. Though the 3-D panel method requires comparatively long computation time, it is believed that the method gives good results without any limitation in ship speed and range of frequency for computation. In the 3-D panel method the source singularity representing translating and pulsating Green function is used and Hoff's method is adopted for the numerical calculation of the Green function. The computation time can be reduced by using the symmetry relationship with respect to longitudinal axis. In this paper the strip method and the 3-D panel method are compared for the seakeeping analysis of a high-speed catamaran. The Compared items are the hydrodynamic coefficients, wave exciting forces, frequency response functions and short-term responses in irregular waves.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.6
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• pp.642-653
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• 2008

This study deals with modeling of head-related transfer functions(HRTFs) using principal components analysis(PCA) in the time and frequency domains. Four PCA models based on head-related impulse responses(HRIRs), complex-valued HRTFs, augmented HRTFs, and log-magnitudes of HRTFs are investigated. The objective of this study is to compare modeling performances of the PCA models in the least-squares sense and to show the theoretical relationship between the PCA models. In terms of the number of principal components needed for modeling, the PCA model based on HRIR or augmented HRTFs showed more efficient modeling performance than the PCA model based on complex-valued HRTFs. The PCA model based on HRIRs in the time domain and that based on augmented HRTFs in the frequency domain are shown to be theoretically equivalent. Modeling performance of the PCA model based on log-magnitudes of HRTFs cannot be compared with that of other PCA models because the PCA model deals with log-scaled magnitude components only, whereas the other PCA models consider both magnitude and phase components in linear scale.