• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.655-662
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• 2012

Gas leakage in an oil refinery causes damage to the environment and unsafe conditions. Therefore, it is necessary to develop a technique that is able to detect the location of the leakage and to filter abnormal gas-leakage signals from normal background noise. In this study, the adaptation filter of the finite impulse response (FIR) least mean squares (LMS) algorithm and a cross-correlation function were used to develop a leakage-predicting program based on LABVIEW. Nitrogen gas at a high pressure of 120 kg/$cm^2$ and the assembled equipment were used to perform experiments in a reverberant chamber. Analysis of the data from the experiments performed with various hole sizes, pressures, distances, and frequencies indicated that the background noise occurred primarily at less than 1 kHz and that the leakage signal appeared in a high-frequency region of around 16 kHz. Measurement of the noise sources in an actual oil refinery revealed that the noise frequencies of pumps and compressors, which are two typical background noise sources in a petrochemical plant, were 2 kHz and 4.5 kHz, respectively. The fact that these two signals were separated clearly made it possible to distinguish leakage signals from background noises and, in addition, to detect the location of the leakage.

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.22.1-22.7
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• 2016

Objectives This study analyzed the associations between mobile phone call frequency and duration with non-specific symptoms. Methods This study was conducted with a population group including 532 non-patient adults established by the Korean Genome and Epidemiology Study. The pattern of phone call using a mobile phone was investigated through face-to-face interview. Structured methods applied to quantitatively assess health effects are Headache Impact Test-6 (HIT-6), Psychosocial Well-being Index-Short Form, Beck Depression Inventory, Korean-Instrumental Activities of Daily Living, Perceived Stress Scale (PSS), Pittsburgh Sleep Quality Index, and 12-item Short Form Health Survey where a higher score represents a higher greater health effect. Results The average daily phone call frequency showed a significant correlation with the PSS score in female subjects. Increases in the average duration of one phone call were significantly correlated with increases in the severity of headaches in both sexes. The mean (standard deviation) HIT-6 score in the subgroup of subjects whose average duration of one phone call was five minutes or longer was 45.98 (8.15), as compared with 42.48 (7.20) in those whose average duration of one phone call was <5 minutes. The severity of headaches was divided into three levels according to the HIT-6 score (little or no impact/moderate impact/substantial or severe impact), and a logistic regression analysis was performed to investigate the association between an increased phone call duration and the headache severity. When the average duration of one phone call was five minutes or longer, the odds ratio (ORs) and the 95% confidence intervals (CIs) for the moderate impact group were 2.22 and 1.18 to 4.19, respectively. The OR and 95% CI for the substantial or severe impact group were 4.44 and 2.11 to 8.90, respectively. Conclusions Mobile phone call duration was not significantly associated with stress, sleep, cognitive function, or depression, but was associated with the severity of headaches.

• Journal of Korean Academy of Nursing
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• v.19 no.2
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• pp.160-172
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• 1989

This research was done to clarify the factors related to sexual satifaction in women who have had a hysterectomy, and to idenify which factors had statistically significant influence of sexual satisfaction of the subjacts. The objective of this study was to identify the variables related to sexual adaptation which might be changed by nursing intervention. This was a cross-sectional descriptive correlation study. There were 230 subjects in the study, and they were selected by a convenient sampling method. The tool. for this study was developed by the researcher through modification of the Dergatis Sexual Function Inventory(DSFI). A pilot study was done to determine the necessary modifications. Data collection was done between Sept. 1987 and Du. 1987 using a mailed questionnaire. The characteristics of the subjects were as follows : The mean age of the subjects was 42.3 years and 204(87.4%) of the subjects had nine or more years of education. The mean income of the subjects was 85.8870 won / month, and 179(77%) of them were housewives. The mean number of pregnancies and children were 4.9 and 2.5 respectively. Oophorectomies were included in the surgery for 66(28.7%) of the subjects. Only 12(5.2%) were planning to have more children. Only 88(38.3%) of the subjects had received information prior to the surgery regarding health problems related to the operation and less than half, 111 (48.3%), had received this kind of information before discharge. Lay persons were the source of information about the post-operation status for 196 (85.2%) of the subjects, but the content of the information did not significantly influence the sexual satisfaction score. Only 16(7.0%) of the subjects said they regretted having a hysterctomy while 102(44.3%) said they were pleased to have had a hysterectomy. Ninety (39.1 %) of the subjects reported that their husbands had “stress” and 164(71.3%) of the subjects reported “stress”. The results of this study are summarized as follows : 1. The mean score for sexual satisfaction of the subjects was 34.24 with a possible maximum score of 50.00. Eighty two(35.8%) were responded that they were satisfied with their sexual life but 61 (26.5%) were responded that they were dissatisfied with their sexual life 2. The following 15 factors extracted from the results of the data analysis were significantly related to sexual satisfaction(p＜.05) ; support of husband, body image, emotion, knowledge of sex, menopausal symptoms, sexual behavior, the feelings the subjects had about the hysterectomy, stress for both subject and husband, the number of children, health information given before operation, job, age, level of education and income. The five most important factors influencing sexual satisfaction were identified by using stepwise multiple regression analysis. The most important factor was support of husband, which explained 17.83% of the total variance. The remaining factors in order of significance were : Knowledge of sex, income, job, and emotional status. Those five factors explained 35.16% of the sexual satisfaction. In conclusion, for the care of women who are going to be discharged from hospital after having had a hysterctomy, nurses have to work with the husbands to help them to understand the importance of their support. Nurses also need to make sure that the subjects have an adequeate knowledge of sexual life after a hysterectomy. Also nursing interventions should focus on subjects who do not have a job, who are of low economic status, and the subjects who are under the unpleasant mood.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.3
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• pp.399-407
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• 2012

To evaluate age and gender differences in the relation of cardiovascular risk factors, cognitive impairment, and subclinical carotid atherosclerosis from aged people using by a cross sectional method. Sixty-nine healthy elders living in the community who had not previously undergone carotid ultrasonography were included. We conducted life style surveys, and cognitive function tests including Korean-mini-mental state examination (K-MMSE) and clinical dementia rating-Korean. Various biomarkers from blood were assessed; fasting insulin-like growth factor-1, lipid-profile, high sensitivity C-reactive protein, total homocysteine, glucose, insulin, Homeostasis model assessment (HOMA) for insulin resistance index, vitamin B12, and folate level. Carotid intima-media thickness (C-IMT), and plaques were measured using carotid ultrasonography and aortic ultrasonography, a valid index of atherosclerosis. For the elderly subjects (aged 65-82 years), cognition impairment was more prevalent in females while subclinical atherosclerosis was more prevalentin males. Increased C-IMT has been kept in males, and C-IMT shows increasing trend and the peak at about 80 year-old in females with increasing age. The significant correlations between C-IMT and many vascular risk factors including age, triglyceride, abnormal homocysteinein male, and K-MMSE, insulin, HOMA index and abnormal aortic ultrasonography in female were different in each gender, with the exception of homocysteine (p<0.05). This data suggests that there were differences of age and gender characteristics in terms of subclinical atherosclerosis, cognitive impairment and vascular risk factors in community-living elders. Further larger and longitudinal studies across entire age are required to better understand the effects of risk factors on subclinical atherosclerosis.

• Journal of Agricultural Extension & Community Development
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• v.8 no.1
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• pp.25-40
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• 2001

The purposes of the study were to identify satisfaction and achievement of learning by female learner's characteristics, and to suggest measures to improve quality of education in internet education programs. In order to determine the educational effectiveness associated with the characteristics of learners, this study attempted to employ two way approaches by observing the degree of achievement for learning, which represents an instructor-oriented approach, and the degree of satisfaction for education, which represents a learner-oriented approach to enhance the quality of internet education for female learners. As an approach to evaluate the educational effectiveness, the degree of achievement in learning(Tyler's classical approach), and the degree of satisfaction for education (Scriven's consumer-oriented evaluation model) were utilized. A survey form was developed by the researcher after reviewing the various tools originated from Boshier, Cross, Gagne and Choi, and distributed to a panel of judges that examined the content validity of the instrument. The sample for the study consisted of 160 female learners from three universities in Seoul and capital area, and the survey form was used to collect data for this study. The SPSS WIN program was used in analyzing the data and a series of statistical tests were conducted including frequency, percentile, t-test, ANOVA, correlation, multiple regression, and factor analysis. The statistical significance level was 0.05. The following conclusion were drawn from this study of female internet education. First, it was evident that female internet learners tend to utilize information from internet, and this can be interpreted as participants' positive attitude, and voluntary participation. Second, educational facilities and services should be improved in the future, because the level of satisfaction was low in these areas compared to curriculum and educational methodology. Third, the participating factors influenced by the level of satisfaction for education of learner characteristics were the 'formation of inter-personal relationship and willingness to change' and the 'needs for education on internet', thus appeared that both social and educational needs influenced the level of satisfaction for education. Fourth, the degree of achievement in learning was higher in the order of 1) attitude 2) function 3) knowledge, thus, attitude change was the most important in achievement of learning. Fifth, the individual background that influenced the level of achievement in learning were age and educational experience. As for the individual level of achievement for learning, the younger and more educated group were more satisfied.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.84-89
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• 2003

In this paper, we real-time implemented to the TMS320C5416 the vocoder of variable bit rate applied the SOLA-B algorithm by Henja to the ITU-T G.729A vocoder of 8kbps transmission rate. This proposed method using the SOLA-B algorithm is that it is reduced the duration of the speech in encoding and is played at the speed of normal by extending the duration of the speech in decoding. At this time, we bandied that the interval of cross correlation function if skipped every 3 sample for decreasing the computational amount of SOLA-B algorithm. The real-time implemented vocoder of C.729A and SOLA-B algorithm is represented the complexity of maximum that is 10.2MIPS in encoder and 2.8MIPS in decoder of 8kbps transmission rate. Also, it is represented the complexity of maximum that is 18.5MIPS in encoder and 13.1MIPS in decoder of 6kbps, it is 18.5MIPS in encoder and 13.1MIPS in decoder of 4kbps. The used memory is about program ROM 9.7kwords, table ROM 4.5kwords, RAM 5.1 kwords. The waveform of output is showed by the result of C simulator and Bit Exact. Also, for evaluation of speech quality of the vocoder of real-time implemented variable bit rate, it is estimated the MOS score of 3.69 in 4kbps.

• Journal of Korea Water Resources Association
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• v.40 no.12
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• pp.957-968
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• 2007

It is essential to obtain accurate and highly reliable streamflow data for quantitative management for water resources. Thereafter such real-time streamflow gauging methods as ultrasonic flowmeter and index-velocity are introduced recently. Since these methods calculate flowrate through entire cross-section by measuring partial velocities of it, rational and theoretical basis are necessary for accurate estimation of discharge. The purpose of the present study lies in analysis on the applicability of Chiu#s(1987, 1988) two dimensional velocity distribution equations by applying them to natural rivers and by comparing simulated velocity distributions with observed ones obtained with ADCP. Maximum and mean velocities are calculated from observed data to estimate entropy parameter M. Such isovel shape parameters as h and $\beta_i$ are estimated by object function based on least squares criterion. In case optimized parameters are applied, Chiu#s velocity distributions fairly well simulate observed ones. By using 14 simulated data sets which have relatively high correlation coefficients, properties of parameters are analyzed and h, $\beta_i$ are estimated for velocity-unknown river sections. When estimated parameters are adopted for verification, simulated velocity distributions well reproduce real ones. Finally, calculated discharges display rough agreement with measured data. The results of the present study mean that if parameters related are properly estimated, Chiu#s velocity distribution is likely to reproduce the real one of natural rivers.

• Journal of Chest Surgery
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• v.30 no.11
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• pp.1092-1096
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• 1997

Thromboelastography(TEG) enables a global assessment of hemostatic function to be made from a single blood sample, documenting the interaction of platelets with protein coagulation cascade from the time of the initial platelet-fibrin interaction, through platelet aggregation, clot strengthening and fibrin cross linking to eventual clot Iysis. Thirty-five patients(mean age 34$\pm$ 12) undergoing open heart surgery from April 1st, 1996 to August 31th, 1996 were investigated at preoperatively and immediate, one hour, and 24 hours after cessation of cardiopulmonary bypass using TEG. Comparisons were made between classic hematological indices and TEG data. There were statistically significant correlation between maximal amplitude(MA) and platelet count before CPB, activating clotting time(ACT) and TEG date(R time, K time and a angle) at 24-hour after CPB. The data on the predictive accuracy for postoperative bleeding at 24-hour after CPB, the TEG was significantly better than ACT(57%) or the coagulation profiles(43%) as a predictor of postoperative bleeding, with an accuracy rate of 100% (P=0.0043). In conclusion, TEG seems to be easy to use, clinically accurate, cost effective and provides data which can effectively manage a patient's hemostasis.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.3
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• pp.199-206
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• 2014

In this paper, a scheme to evaluate the response variability for functionally graded material (FGM) beam with varying sectional area is presented. The randomness is assumed to appear in a spatial domain along the beam axis in the elastic modulus. The functionally graded material categorized as composite materials, however without the drawbacks of delamination and occurrence of cracks due to abrupt change in material properties between layers in the conventional composite materials. The functionally graded material is produced by the gradual solidification through thickness direction, which endows continuous variation of material properties, which makes this material performs in a smooth way. However, due to difficulties in tailoring the gradients, to have uncertainty in material properties is unavoidable. The elastic modulus at the center section is assumed to be random in the spatial domain along the beam axis. Introducing random variables, defined in terms of stochastic integration, the first and second moments of responses are evaluated. The proposed scheme is verified by using the Monte Carlo simulation based on the random samples generated employing the spectral representation scheme. The response variability as a function of correlation distance, the effects of material and geometrical parameters on the response variability are investigated in detail. The efficiency of the proposed scheme is also addressed by comparing the analysis time of the proposed scheme and MCS.

• Tuberculosis and Respiratory Diseases
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• v.81 no.1
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• pp.73-79
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• 2018

Background: Osteoporosis is a common disease that occurs comorbidly in patients with chronic inflammatory airway diseases, including asthma, chronic obstructive pulmonary disease (COPD), and asthma-COPD overlap syndrome (ACOS). However, the prevalence of osteoporosis in patients with ACOS has not widely been evaluated. Therefore, we investigated the prevalence of osteoporosis and its relationship with the clinical parameters of patients with asthma, COPD, and ACOS. Methods: This was a retrospective, cross-sectional study. Bone mineral density (BMD), lung function tests, and disease status evaluations were conducted. Results: A total of 321 patients were enrolled: 138 with asthma, 46 with ACOS, and 137 with COPD. One hundred and ninety-three patients (60.1%) were diagnosed with osteoporosis (53.6% of asthma, 65.2% of ACOS, and 65.0% of COPD). Patients with ACOS showed a significantly lower BMD and T-score than did those with asthma. In addition to age, sex, and body mass index (BMI), which were previously reported to be associated with BMD, BMD also had a negative correlation with the diagnosis of ACOS, as compared to a diagnosis of asthma, after adjusting for age, sex, BMI, smoking, and inhaled corticosteroid use (p=0.001). Among those patients with COPD and ACOS, BMD was negatively associated with the COPD Assessment Test (CAT) after adjustment (p<0.001). Inhaled corticosteroid was not associated with the prevalence of osteoporosis and BMD. Conclusion: Patients with ACOS, particularly aged and lean women, should be more carefully monitored for osteoporosis as compared to patients with asthma.