• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.877-882
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• 2011

In this paper, thermal deformation of a double ring structure using digital image correlation technique (DIC) was measured. The double ring structure consisted of two parts; the inner ring was aluminium which had a large thermal expansion coefficient and the outer ring was titanium which had a small thermal expansion coefficient. We heated the double ring structure from $50^{\circ}C$ to $200^{\circ}C$ in a chamber and at the same time, two cameras captured surface images of the double ring structure. Initially, there was a 21 ${\mu}m$ gap between the inner ring and outer ring. The gap was closed at around $80^{\circ}C$ and after that, two rings expanded together. In order to compare the experimental results with analysis results, a finite element analysis was performed using ANSYS. The results of DIC measurement and ANSYS analysis were compared and agreed well.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.18-25
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• 1996

Power input in stirred vessel is especially important in the design of mixers, as well as the evaluation of mixing processes. A type of baffles in mechanically agitated vessels and power employed are major factors that determine the stirring efficiency in a large scale, multi-step processes. In the present study, power input in the totally baffled agitated vesseles was compared systematically in connection with several previous studies and adequate power input correlation was found to be : $Np_{(pitch)}=({\theta}/90^{\circ})Np_{(90^{\circ})}$ Power number correlation was dependent upon the distance of among the impeller in the agitated vesseles, as follows : $$Np=7.09(n_p)^{0.7}(\frac{b_(double)}{d})(\frac{H}{D})^{0.18}$$, $${n_p}^{0.7}(\frac{b_{(double)}}d)$$<2 $$Np=8.73\{(n_p)^{0.7}(\frac{b_{(double)}}{d})\}^{0.7}(\frac{H}{D})^{0.18}$$, $${n_p}^{0.7}(\frac{b_{(double)}}d)$$>2.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.123-129
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• 2000

This paper addresses a new double detection algorithm which is based on the fuzzy control in the adaptive echo canceller of communication system. In this method, the two input of the fuzzy inference for detecting double talk condition are used. The one is the cross-correlation coefficient between the error signal and the primary signal which is the summed signal of the real echo signal and the near-end signal. The other is the cross-correlation coefficient between the estimation error signal and the primary signal. The fuzzy controller made a fuzzification for two inputs by the membership functions of trapezoid and them became the composition using inference rules. The composed result is defuzzificated by the center gravity method. The output is compared with two threshold values to detect double talk and echo path variation effectively. It is confirmed by computer simulation that this fuzzy double talk detector is able to track echo path variation accurately.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.2
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• pp.136-141
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• 2008

Background and Objectives: Laryngopharyngeal reflux (LPR) is a very common disease among outpatients of department of otorhinolaryngology. Although there are several diagnostic tools for LPR disease and ambulatory 24-hour double-probe pH monitoring is gold standard method, empirical diagnosis by reflux symptom index and reflux finding score (RFS) are mainly used. So we analyzed the relationship between ambulatory 24-hour double-probe pH monitoring and RFS in patients with LPR. Subjective and Method: Fifty patients with LPR symptoms and abnormal RFS and ambulatory 24-hour double probe monitoring were enrolled. Each items and sum of laryngeal reflux score were compared the results of ambulatory 24-hour double-probe pH monitoring in upper (UES) and lower (LES) esophageal sphincter. Results: There were no significant correlation between the results of ambulatory 24-hour double-probe pH monitoring in UES (pH<4 and pH<5) and each item and sum of RFS. However, supine time and reflux number of UES (pH<5) were showed the partial correlations with diffuse laryngeal edema and thick endolaryngeal mucus (p=0.03, p=0.01). Although there were no relationship between the results of ambulatory 24-hour double-probe pH monitoring in LES and sum of RFS, the significant correlations presented between granuloma and total time (p=0.008), upright time (p=0.008, reflux number (p=0.049) of LES. Conclusion: Although granuloma among items of RFS showed significantly correlation with the results of ambulatory 24-hour double-probe pH monitoring in LES, there were no significant correlation between the results of ambulatory 24-hour double-probe pH monitoring in UES and LES and items and sum of RFS.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.705-711
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• 2013

In this paper, we present a low-complexity non-coherent demodulation algorithm and hardware architecture for LR-WPAN systems which can support the variable data rate for various applications. The need for LR-WPAN systems that can support the variable data rate is increasing due to the emergence of various sensor applications. Since the existing symbol based double correlation (SBDC) algorithm requires the increase of complexity to support the variable data rate, we propose the sample based double correlation (SPDC) algorithm which can be implemented without the increase of complexity. The proposed non-coherent demodulator was designed by verilog HDL and implemented with FPGA prototype board.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.355-363
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• 2022

Purpose : The purpose of this study was to investigate the double mediating effect of ego-resilience and impulsivity in the effects of smartphone addiction on depression among office workers. Research design, data and methodology : The subjects of this study were office workers working in four cities: Seoul, Daejeon, Chungnam, and Chungbuk Province, and the total number of respondents was 286. Descriptive statistics, difference test (t-test, ANOVA), correlation analysis, and double-mediated effect analysis were used for statistics. Results : The results of this study are as follows. First, as a result of the difference analysis, there was no difference in depression according to the general characteristics of the subjects of this study, such as gender, age, marital status, and salary. Second, as a result of correlation analysis, smartphone addiction showed a negative correlation with ego-resilience, and a positive correlation with impulsivity and depression. Also, ego-resilience showed negative correlation with impulsivity and depression. Impulsivity showed a positive correlation with depression. Third, as a result of dual mediating effect analysis, it was found that ego-resilience and impulsivity played double-mediated role between smartphone addiction and depression. Conclusions : Based on the results of this study, theoretical measures centered on ego-resilience were discussed and presented in order to positively induce the decrease in impulsivity and depression due to smartphone addiction among office workers.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.4
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• pp.247-253
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• 2006

Power consumption for double-stage paddle impeller in spherical and cylindrical agitated vessel was measured over a wide range of Reynolds number from laminar to turbulent flow regions. The power correlation was obtained which was applied to both spherical and cylindrical vessel, when the apparent diameter of the spherical vessel was equal to the diameter of the cylindrical vessel which had a height equal to its diameter and had the same volume as the spherical vessel. The power consumption for the double-stage impeller was dependent upon the distance of among the impeller in the agitated vessels, as follows: $$f/2={\frac{C_L}{Re_G}}+{\frac{Ct}{2}}({\frac{C_tr}{Re_g}}+Re_g)^{-m}$$

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.147-159
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• 1995

This study was conducted to introduce fundamental data of hand-arm vibration and noise exposure levels with impact wrenches(double-hammer impact wrenches and oil-pulse impact wrenches) used in automobile assembly lines considering the process variables and tool variables. In studing, products per day, required time screwing the bolts or nuts per bolts or nut were considered as process variables, and capacity of bolts or nuts, air consumptions per minute, tool weights, RPM were considered as tool variables. Hand-arm vibration levels of 3 axis in each hand were measured using the instruments compling with ISO/DIS 5349 and noise levels were measured using a noise logging dosimeter. The results were as follows : 1. Required time to screwing the bolt or nut by oil-pulse impact wrenches is shorter than double-hammer impact wrenches but total daily exposure time of oil-pulse impact wrenches was higher than double-hammer impact wrenches because the number of bolts or nuts per cycle was many. 2. Oil-pulse impact wrenches have been used to screwing the large bolt or nut in comparing with double-hammer impact wrenches and required time to screwing the bolts or nuts were shorter than double-hammer impact wrenches because oil-pulse impact wrenches were using high RPM and large air consumption per minute. Noise level of oil-pulse impact wrenches was 8 dB(A) lower than double-hammer impact wrenches. 3. Dominant hand-arm vibration levels of double-hammer impact wrenches in each hand were $8.24m/sec^2$ of Zh axis in right hand and $9.60m/sec^2$ of Xh axis in left hand. Dominant hand-arm vibration level of oil-pulse impact wrenches in each hand was $2.59m/sec^2$ of Xh axis in right hand and $3.23m/sec^2$ of Yh axis in left hand. 4. In double-hammer impact wrenches, corresponding hand-arm vibration levels of Xh, Yh, Zh axis in left hand were higher than hand-arm vibration levels of right hand in 3 axis. In oil-pulse impact wrenches, Xh axis of right, Yh axis of left, Zh axis of left were higher than the corresponding hand-arm vibration levels of Xh, Yh, Zh axis in right and left hand. 5. Correlation coefficients among Xh, Yh. Zh axis of right and left hand hand-arm vibration levels in double-hammer impact wrenches and oil-pulse impact wrenches were commonly high in Yh axis and correlation coefficients of Yh axis in double-hammer impact wrenches and oil-pulse impact wrenches were 0.76 and 0.86,respectively. 6. As a measure repetitiveness, plotting total daily exposure time with the number of bolts or nut per cycle, direct correlation was shown between repetitiveness and hand-arn vibration exposure, and correlation coefficient between the number of bolts or nut per cycle and total daily exposure time in double-hammer impact wrenches, oil-pulse impact wrenches were 0.84 and 0.50, respectively. 7. Considering the total acceleration level and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption in right hand, and bolt or nut capacity in left hand were commonly the variable that explainability was high. Considering the noise and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption per minute was commonly the variable that explainability was high.

• Journal of the Korean Home Economics Association
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• v.44 no.6 s.220
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• pp.47-58
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• 2006

This research focused on the family stress and family strengths in double-income couples. The subjects of this study were 171 double-income couples, in the Kyeongnam Area, Korea. The major findings from the study are as follows. 1) The degree of family stress of the husband and wife in double-income couples was 2.90 and 2.97, respectively, on a scale of 0-5.0. The significant variables were economic level, self-esteem and marital satisfaction in double-income couples' husband, and having a housework-helper, job satisfaction, self-esteem and marital satisfaction in double-income couples' wife. 2) The degree of family strengths of the husband and wife in double-income couples was 3.84 and 3.82, respectively, on a scale of 0-5.0. The significant variables were job satisfaction, self-esteem and marital satisfaction in double-income couples' husband, and the educational level, job type, self-esteem and marital satisfaction in double-income couples' wife. 3) There was a close inverse correlation between the lamely stress and family strengths in the husband and wife of double-income couples.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.4
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• pp.430-439
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• 1985

Conjugate natural convection in double enclosed annuli between horizontal concentric cylinders has been studied by the numerical analysis and experimental measurements. The interface conditions between the liquid and the solid of middle shell are obtained through the correlation factor based on the ratio of solid to fluid thermal conductivities and the Prandtl number. The characteristics of conjugate heat transfer are discussed under various dimensionless parameters such as conductivity ratios, shell thickness, diameter ratios, Prandtl number, and Rayleigh number. It is found that the average equivalent conductivity K over var $_{eq}$ does not depend on the conductivity ratios and shell thickness. The K over bar $_{eq}$ however, depends on the Prandtl number and the Rayleigh number.