• Journal of Families and Better Life
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• v.33 no.5
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• pp.37-53
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• 2015

The purpose of this study is to examine the differences in perceived time pressure between employed and non-employed married women in Korea. The sample of married couple from the Korean Time Use Survey 2009 (n = 6,948 couple diaries) was used to examined the difference in the level of perceived time pressure over the life cycle of two group. This study also investigated the married women's time use, husband's time use as well as hour of domestic outsourcing and whether such factors are associated with lowering perceived time pressure of married women. Results showed employed wives felt almost 3 times more time pressed than non-employed wives, and the gap mostly remained over different life cycles. Total work hours were associated with increasing the time pressure of both groups of women, while regenerating time was associated with ameliorating time pressure. The result suggests that the time pressure gap between employed and non-employed wives can be partly due to the relative length of total labor hours and regenerating time among the two groups. Ordered logit analysis revealed that husband's paid work hours were not associated with wive's feeling rushed, but husband' unpaid work hours were positively linked with time pressure of their wives. Results indicated if employed or non-employed wives are feeling very busy, there is a high chance that husband might give them some help. We found employed wives spend more hours on housework outsourcing, and purchasing goods for housework was not associated with lowering the feeling of pressure of employed wives. There were both similarity and difference in factors associated with women's feeling pressed among employed and non-employed wives. It implies that social process and it's strategies to alleviate the time pressure can be different by women's employment status.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.653-660
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• 1998

The purpose of this paper is to analyze the electromagnetic field characteristics of microstrip array antenna with the FDTD(finite difference-time domain method). Finite difference equations of Maxwell's equations are defined in rectangular coordinate systems. To simulate the unbounded problem like a free space, the Mur's absorbing boundary condition is also used. After modeling the microstrip array antenna with the grid structure, the transient response of the field distribution is depicted in the time domain.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.294-300
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• 2001

Effect of bean water concentration and incubation time of Yukwa paste as well as packaging method on the quality of Yukwa was investigated. Quality loss in Yukwa during storage was dependent on the packaging method such as bamboo packaging at $30^{\circ}C$, nitrogen packaging at $30^{\circ}C$ and LDPE packaging at $-18^{\circ}C$. Peroxide value increased with bean water concentration, but showed no significant difference by incubation time. The hardness of Yukwa decreased with the increase of bean water concentration, incubation time, and storage time but showed no significant difference by packaging method. Sensory evaluation after storage for 3 months showed that Yukwa color was significantly influenced by packaging method and bean water concentration. The volume was also significantly influenced by bean water concentration and incubation time. Off-flavor showed significant difference by storage method. Tenderness, taste and overall desirability showed significant difference by bean water concentration. Crispness showed significant difference by storage method and bean water concentration.

• PNF and Movement
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• v.6 no.2
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• pp.19-30
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• 2008

Purpose : This study was performed for find out temporal spatial parameter of the gait according to age. Method : Four groups of healthy people were allocated randomly in this study : group I(little child, 15), group II(child, 18) and group III(young people, 17), group(elder people, 16). This study was performed from 01 December to 31 December in 2007. Results : The results were as follows : 1. The swing phase was the longest group II, group IV was the shortest. Each groups, there was significant difference in swing phase(p<.05). 2. The stance phase was the longest group IV, group II was the shortest. Each groups, there was significant difference in stance phase(p<.05). 3. The single support time was the longest group II, group IV was the shortest. Each groups, there was significant difference in single support time(p<.05). 4. The double support time was the longest group IV, group II was the shortest. Each groups, there was significant difference in double support time(p<.05). 5. The gait velocity was the fastest group II, group I was the slowest. Each groups, there was significant difference in gait velocity(p<.05). 6. The toe in/out was very increased group IV, group I was very decreased. Each groups, there was significant difference in toe in/out(p<.05). 7. The cadence was the highest group I, group IV was the lowest. Each groups, there was significant difference in cadence(p<.05). 8. The step length was the longest group III, group I was the shortest. Each groups, there was significant difference in step length(p<.05). 9. The step length asymmetry ratio was the highest group IV, group III was the lowest. Each groups, there was no significant difference in step length asymmetry ratio(p>.05). 10. The single support time asymmetry ratio was the highest group I, group IV was the lowest. Each groups, there was no significant difference in single support time asymmetry ratio (p>.05). 11. The FAP was the highest group III, group I was the lowest. Each groups, there was significant difference in FAP(p<.05).

• Journal of the Korean Institute of Navigation
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• v.18 no.4
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• pp.137-146
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• 1994

In this paper, a new algorithm to measure the ultrasonic travel time is proposed, which is fundamental to estimate distance depth and volume in several media. Pulse wave has been used to measure travel time of transmitted signal. However, due to the characteristic of transducer and propagation, the received signal is so distorted that it is difficult to measure travel time, which is propagation, the received signal is so distorted that it is difficult to measure travel time, which is to be time difference between transmitted and received signals. In this proposed method, transmitted and received signal are transformed respectively into norm phase newly designed by this paper and displayed on phase-time curve. And travel time is simply determined by the arithmetic numerical mean of time difference at the identical norm phase on the phase-time curves of transmitted and received signals. This method has several features; firstly, travel time is calculated analytically with high accuracy by least square error method, secondly, it is useful to compare the difference of signal magnitude for time information, thirdly, noise and discrete errors are relatively small, finally, the measurement accuracy is not influenced by D.C. bias. In particular, this method is useful and applicable to measuring very short distance and sound speed with high accuracy.

• Current Optics and Photonics
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• v.2 no.1
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• pp.34-38
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• 2018

An X-band microwave photonic (MWP) filter using switch-based fiber-optic delay lines has been proposed and experimentally demonstrated. It is composed of two electro-optic modulators (EOMs) and $2{\times}2$ optical MEMS-switch-based fiber-optic delay lines. By changing time-delay difference and coefficients of each wavelength signal by using fiber-optic delay lines and an electro-optic modulator, respectively, a bandpass filter or a notch filter can be implemented. For an X-band MWP filter with four channel elements, fiber-optic delay lines with the unit time-delay of 50 ps have been experimentally realized and the frequency responses corresponding to the time-delays has been measured. The measured frequency response error at center frequency and the time-delay difference error were 180 MHz at 10 GHz and 3.2 ps, respectively, when the fiber-optic delay line has the time-delay difference of 50 ps.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.149-152
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• 2002

In this paper, an adaptive interference canceller (AIC) Is applied to the space-time coded DS-CDMA system in fading channels with arrival time difference from multiple transmit antennas In a CDMA system, arrival time difference causes not only inter-antenna and Inter-symbol interference but also multiple-access Interference even in a downlink. To mitigate the effect of the Interferences an AIC and ML decoding joint scheme Is proposed fur a space-time coded DS-CDMA system in which an adaptation process of tile AIC is merged in the Viterbi decoding algorithm. The performance of the proposed receiver is evaluated for the system with two transmit antennas. It is shown that the proposed receiver achieves significant performance improvement over the ML decoding receiver without the AIC

• Journal of Distribution Science
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• v.17 no.12
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• pp.63-70
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• 2019

Purpose: This study was to propose effective deployment of automatic external defibrillators (AEDs) installed at general supermarkets. Research design, data, and methodology : We conducted interview and data surveys on 72 large distributors in Seoul and Gyeonggi province in South Korea. The content of this survey was consisted of general status on the general supermarkets, AED deployment and management regarding public access defibrillation (PAD). G^⁎Power (v 3.1.9.4; Universität Kiel, Kiel, Germany) was also used to analyze statistical power. Radius and actual distance, radius and retrieval time were compared by t-test at α=.05. respectively. Results : Difference between the radius (102.7 meters) and the actual distance (187.8 meters) was 85.1m, it had statistically significant difference (p<.001). The actual distance was longer compared to the radius distance. Difference between the radius (114.1 seconds) and the retrieval time (208.7 seconds) was 94.6s, it had statistically significant difference (p<.001). The retrieval time took longer compared to the radius time as well. Conclusions : The finding shows that only 45.9% of the general supermarkets are satisfied with the actual AED coverage within 3 minutes. This needs to enhance AED deployment to reduce defibrillation time and AED management to boost application in South Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3104-3109
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• 2009

The technology of direction finding is very important to find the direction of emitters for ELINT(electronic intelligence) system. The principle of TDOA(time difference of arrival) is to receive an emitter signal with two antennas, measure the time difference between two antennas, and converse the time difference to direction difference. This technology can be used in broadband frequency system and make the system very simple because a phase-discriminator and a voltage comparator are not needed. For fine DF accuracy, high time resolution receiver and long basis line antennas are needed. The DF accuracy of noise added signals is simulated with different time

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.483-488
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• 2015

Objective : The purposes of this study was to analyze the locomotive movement of forelimbs according to changes in velocities in the quadruped cadence of horses. Methods : Horses selected as subjects consisted of Jeju pony horses (heights of withers: $1.23{\pm}0.51$). Two camcorders (HDR-HC7/HDV 1080i, Sony Corp, Japan) were used to capture the movement of the horses' forelimbs at a rate of 60 frames/sec. Additionally, raw data was collected from Kwon3D XP motion analysis package ver 4.0 program (Visol, Korea) with DARTFISH (DFKREA., Korea) video software solution. The variables analyzed consisted of 1 step lengths, 1 stride lengths, stance time, swing time, 1 stride time, velocity while walking, and trot of the horses. A two-way ANOVA and paired t-test of the variables by velocity and phase were treated at .05 level of significant difference, statistically. Results : The time elapsed of walk(stance: 0.63 sec[63.86%], swing: 0.35 sec[36.14%], 1 stride time: 0.99 sec respectively) showed significant difference with more delay than that of trot(stance: 0.29 sec[45.73%], swing: 0.34 sec[54.27% ], 1 stride time: 0.63 sec respectively), and also showed significant difference at trot in interaction (stance time>tort swing>walk swing>walk stance). The 1 step lengths and stride lengths in trot showed significant difference with longer than that of walk. Velocity of Trot showed significant difference statistically with higher than that of walk Conclusion : The horses' velocity during 1 step lengths and 1 stride lengths showed a proportional relationship, but the correlation between the horses' velocity and stance time showed a negative relationship during the quadruped cadence.