• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.52-57
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• 2001

The passive ranging estimation techniques using a focused beamformer have been studied under the water. It is well known that the passive ranging estimation method using a focused beamformer is excellently evaluated. Among these, the passive ranging sonar is known to have a good performance under low signal-to-noise. ratio. However, its performance is degraded in multi-source environments. In this paper, we proposed the technique using dual focused beamformers to estimate the range. And when the sampling frequency is low, it is very difficult to steer the focused beam to the desired direction, as a result of this, the low performance occurs because of a distorted beam pattern. In this paper, we study the effect of sampling rate on passive ranging by using focused beamformer. And we verified the performance of the proposed method via computer simulation.

• ETRI Journal
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• v.26 no.6
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• pp.555-559
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• 2004

We propose an efficient digital IF down converter architecture for dual-mode WCDMA/cdma2000 based on the concept of software defined radio. Multi-rate digital filters and fractional frequency conversion techniques are adopted to implement the front end of a dual-mode receiver for WCDMA and cdma2000. A sub-sampled digital IF stage was proposed to support both WCDMA and cdma2000 while lowering the sampling frequency. Use of a CIC filter and ISOP filter combined with proper arrangement of multi-rate filters and common filter blocks resulted in optimized hardware implementation of the front end block in 292k logic gates.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.369-372
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• 1994

In this paper, a voltage type dual PWM converter which achives the bidirectional power flow between a AC supply and a DC bus voltage is described. In PWM modulator, there exist a time difference between the sampling time and carrier wave, it achieves stable modulation even the disturbance in the synchronous AC source voltage. And this paper proposes the compensation method and the control method related a disturbance of synchronous signal using the low pass filter and phase shifter for the stable modulation. As a result the voltage type dual PWM converter makes the imput current wave as sinusoid, and performs the high power factor driving.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.105-116
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• 2000

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swril flow(DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microrstructure using thermophoretic sampling particle diagnostic(TSPD) as TEM were carried out. The NOx, $CO_2$,$O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• Korean Journal of Occupational Health Nursing
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• v.20 no.2
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• pp.221-229
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• 2011

Purpose: The purpose of this study was to identify the relationship between family stress and health promoting behavior (HPB) of the dual earner couples. Methods: The subjects were 312 dual earner couples selected from G city by convenient sampling. The data were collected from October 1 to November 10, 2009, and analyzed using frequencies, t-test, ANOVA, Duncan test, and Pearson's correlation coefficient with the SPSS/WIN 17.0. Results: The mean score of family stress and HPB on the subjects were 2.98 and 3.29 respectively. Family stress showed a significant difference according to monthly income. HPB showed a significant difference according to exercise, smoking, and drinking. HPB had a significantly positive correlation with family stress. Conclusion: This study suggested that we should develop programs to increase regular exercise and to quit drinking and smoking for the dual earner couples in occupational health nursing.

• Journal of the Korean Society of Combustion
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• v.5 no.1
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• pp.67-79
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• 2000

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swril flow(DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microstructure using thermophoretic sampling particle diagnostic(TSPD) as TEM were carried out. The NOx, $CO_2,\;O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.137-146
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• 2015

Singh (2013) considered the dual problem to the calibration of design weights to obtain a new generalized linear regression estimator (GREG) for the finite population total. In this work, we have made an attempt to suggest a way to use the dual calibration of the design weights in case of multi-auxiliary variables; in other words, we have made an attempt to give an answer to the concern in Remark 2 of Singh (2013) work. The same idea is also used to generalize the GREG estimator proposed by Deville and S$\ddot{a}$rndal (1992). It is not an easy task to find the optimum values of the parameters appear in our approach; therefore, few suggestions are mentioned to select values for such parameters based on a random sample. Based on real data set and under simple random sampling without replacement design, our approach is compared with other approaches mentioned in this paper and for different sample sizes. Simulation results show that all estimators have negligible relative bias, and the multivariate case of Singh (2013) estimator is more efficient than other estimators.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.111-112
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• 2013

An experimental study of a dual swirl burner was conducted to analyze NOx emission in the lean conditions. The dual swirl burner is composed of a combination of swirling jet premixed(main section) and diffusion flames(pilot section). It was operated with a co-swirling configuration and overall equivalence ratios between 0.6 and 0.8. The purpose of this study is to analyze experimentally the characterization of flame temperature and NOx concentration in reacting zone and to supply the useful experimental data for numerical simulations. The measurements of temperature and NOx concentration were captured using a thin digitally-compensated thermocouple and a sampling quartz probe with quenching effect of sudden expansion, and were measured by the NOx analyzer of chemiluminescence method. We could analyse the NOx emission characteristics comparing the temperature distributions in the lean equivalence ratios.

• Korean Institute of Interior Design Journal
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• v.27 no.3
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• pp.3-13
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• 2018

Although the number of dual low-income families continues to increase, working mothers are suffering from difficulties from housework and child rearing due to the economic difficulties and poor residential environment. By understanding the needs about community space and child-care support services, this study will look into planning cooperative child-care environments for dual low-income families with infants and children. Through purposive sampling this research targeted 151 dual income families with an average monthly income level of 1-3 in Seoul. The collected data was analyzed by frequency analysis, descriptive statistics, and independent sample t-test using SPSS. The research results are as follows: According to the review, respondents responded positively to cooperative child-care. Out of the 20 general community spaces, the need for an indoor playground, recreation room, day nursery, separate garbage and reading room ranked high. Overall, 21 child-care community spaces and 11 child-care support services were generally rated highly.

• Fashion & Textile Research Journal
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• v.10 no.2
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• pp.155-163
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• 2008

The college students selected by random sampling were classified into several groups by their cosmetic impulse buying pattern and the internal characteristics that cause them. Their shopping orientation, life styles, makeup self-confidence, makeup interest and self-image were the subjects of comparative analysis. The results of this research can be summarized as follows.; fashion leader was classified fashion dual leader, fashion opinion leader, fashion innovator and fashion follower. The fashion dual leader and fashion innovator were more impulse buying orientated. The fashion dual leader and fashion innovator were highly evaluated in intellectual self faithfulness and life decoration preference style. The fashion dual leader and fashion innovator attached great importance to leisure pursuit and name brand preferring shopping. They showed the tendencies to the makeup self-confidence and makeup interest. But the fashion follower showed quite different tendencies. The fashion dual leader and fashion innovator perceived themselves as varied life style. These internal characteristics were supposed to contribute to their impulse buying.