• Journal of Engineering Education Research
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• v.17 no.1
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• pp.57-64
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• 2014

This study has a purpose mainly to analyze the team interaction change by the duration of time in the Capstone-Design activities according to MBTI Modes. Study objects are four students of Mechanical Engineering at School of Engineering in C University located in Daejeon, and the team interaction change was analyzed through IPA (Interaction Process Analysis) method. From the result, first, ESTP showed the change of increase in interaction by the time duration of initial, mid, late periods in 'social-emotional area: positive' and 'task area: question', and the change of decrease by the same time duration of periods in 'task area: solution'. Also, there was no change in 'social-emotional area: negative' because there was no interaction. Second, ESFJ showed the change of decrease in interaction by the time duration of initial, mid, late periods in 'social-emotional area: positive' and 'task area: question', and the change of increase by the same time duration of periods in 'task area: solution' and 'social-emotional area: negative'. Third, ISTJ showed the change of decrease in interaction by the time duration of initial, mid, late periods in 'social-emotional area: positive', 'task area: question' and 'social-emotional area: negative', and the change of increase by the same time duration of periods in 'task area: solution'. Fourth, ENFP showed the change of decrease by the time duration of initial, mid, late periods in 'social-emotional area: positive', 'task area: solution' and 'social-emotional area: negative', and the change of increase by the same time duration of periods in 'task area: question'.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.12
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• pp.1608-1614
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• 2000

For the purpose of obtaining fundamental data which is needed to develope combustion system of LPG engine, we made constant volume chamber and analyzed flame propagation characteristics under different intial temperature, initial pressure and equivalence ratio which affect combustion of LPG. We investigated flame propagation speed of each fuel using laser deflection method and compared with the investigated flame propagation speed of each fuel using laser deflection method and compared with the results of image processing of flame. As a result, the maximum flame propagation speed was found at equivalence ratio 1.0 and 1.1 for LPG and gasoline, respectively. In the lean region, we can see that flame propagation speed of LPG surpasses that of gasoline. On the contrary, flame propagation speed of gasoline surpasses LPG in the rich region. As initial temperature and initial pressure were higher, flame propagation speed was faster. And, as equivalence ratio was larger and initial temperature was higher, combustion duration was shorter and maximum combustion pressure was higher.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.4
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• pp.229-237
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• 2022

The sewer capacity design have been based on the Huff model or the rational equation in South Korea and often failed to determine optimal capacity, resulting in frequent urban flooding or over-sizing. A time distribution of rainfall (i.e., Huff or ABM method) could be used instead of a rainfall hyetograph obtained from statistical analysis of previous rainfalls. In this study, the Huff method and the ABM method, which predict the time distribution of rain intensity, which are widely used to calculate sewage pipe drainage capacity using the SWMM, were compared with the standard rainfall intensity hyetograph of Seoul. If the rainfall duration was 30 minutes to 180 minutes, the rainfall intensity value calculated by the Huff model tended to be less than the rainfall intensity value of the standard rainfall intensity in the initial 5-10 minutes. As a result, more than 10% to 30% of under-design would be made. In addition, the rainfall intensity value calculated by the Huff model from the section excluding the initial 5-10 minutes of rainfall to the rainfall duration was calculated larger than the value using the standard rainfall intensity equation, which would result in an over-design of 10% to 30%. In the case of a relatively long rainfall duration of 360 minutes (6 hours) to 1,440 minutes (24 hours), it showed an lower rainfall intensity of 60 to 90% in the early stages of rainfall, but the problem of under-design had been solved as the rainfall duration time had elapsed. On the other hand, in the alternating block method (ABM) method, it was found that the rainfall intensity at the entire period at each assumed rainfall duration accurately matched the standard rainfall intensity hyetograph of Seoul.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7A
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• pp.569-580
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• 2012

In this paper, an enhanced initial ranging algorithm for large-cell coverage fixed wireless communication system is proposed. In typical wireless communication system such as WiBro, because a round-trip delay between a transmitter and a receiver is within one OFDM (Orthogonal Frequency Division Multiplexing) symbol duration, a frequency-domain differential correlation method is generally used. However, the conventional method cannot be applied due to an increase of a maximum time delay in large-cell system. In case of an accumulative differential method, estimation errors can occur because of frequent sign transitions. In this paper, therefore, we propose an algorithm which can estimate a total timing offset in a ranging channel structure for 15 km cell. The proposed method can improve performance by sign comparison based sign error correction rule between the estimated values and using a weighting scheme based on channel correlation, the number of accumulations, and the noise reduction effect in normalization process. Also, it can estimate the integer timing offset of symbol duration by comparing peak-powers after compensating for the fractional timing offset of symbol duration.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.608-619
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• 2017

In this paper, the effects of parameters related to the residual stress induced due to laser shock peening process to determine mitigation of the initial tensile residual stresses are discussed, such as the maximum pressure, pressure pulse duration, laser spot size and number of laser shots. In order to estimate the influence of the initial tensile residual stresses, which is generated by welding in 35CD4 50HRC steel alloy, the initial condition option was employed in the finite element code. It is found that $2{\times}HEL$ maximum pressure and a certain range of the pressure pulse duration time can produce maximum mitigation effects near the surface and depth, regardless of the magnitudes of tensile residual stess. But plastically affected depth increase with increasing maximum pressure and pressure pulse duration time. For the laser spot size, maximum compressive residual stresses have almost constant values. But LSP is more effective with increasing the magnitudes of tensile residual stress. For the multiple LSP, magnitudes of compressive residual stresses and plastically affected depths are found to increase with increasing number of laser shots, but the effect is less pronounced for more laser shots. And to conclude, even though the initial tensile residual stresses such as weld residual stress field are existed, LSP is enough to make the surface and depth reinforcement effects.

• Journal of the Korean Society of Combustion
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• v.1 no.2
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• pp.21-29
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• 1996

Flame propagation characteristics of propane-air mixtures were experimentally investigated in constant-volume combustion chambers. Flame propagation process was observed as a function of mixture strength, initial mixture temperature and initial mixture pressure in quiescent mixtures. A cylindrical combustion chamber and a spherical combustion chamber contain a pair of parallel windows through which optical access into the chamber can be provided. Laser two beam deflection method was adopted to measure the local flame propagation, which gave information on the flame size and flame propagation speed. Pressure development was also measured by a piezoelectric pressure transducer to characterize combustion in quiescent mixtures. Burning velocity was calculated from flame propagation and pressure measurements. The effect of flow on flame propagation was also investigated under flowing mixture conditions. Laser two beam method was found to be feasible in measuring flame propagation of quiescent mixtures. Flame was observed to propagate faster with higher initial mixture temperature and lower initial pressure. Combustion duration was shortened in the highly turbulent flowing mixtures.

• Journal of Mechanical Science and Technology
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• v.16 no.7
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• pp.935-941
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• 2002

This work is to investigate the combustion characteristics and flame propagation of the LPG (liquified petroleum gas) and gasoline fuel. In order to characterize the combustion processes of the fuels, the flame propagation and combustion characteristics were investigated by using a constant volume combustion chamber The flame propagation of both LPG and gasoline fuels was investigated by the laser deflection method and the high-speed Schlieren photography. The result of laser deflection method show that the error of measured flame propagation speed by laser method is less than 5% compared with the result of high-speed camera. The flame propagation speed of the fuel is increased with the decrease of initial pressure and the increase of initial temperature in the constant volume chamber. The results also show that the equivalence ratio has a grate effect on the flame speed, combustion pressure and the combustion duration of the fuel-air mixture.

• Speech Sciences
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• v.13 no.3
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• pp.97-105
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• 2006

The objective of this study was to analyze the acoustic patterns of Japanese /t/ produced by 40 Korean speakers in order to find an effective method of teaching it to Koreans. The experimental data consisted of 400 /t/ phonemes in word initial or non-initial positions of 10 words. Informants were in their twenties and raised in Daejeon and the surrounding area. Results showed that there were distinctive trends in duration and intensity of the major and non-major groups productions. Both groups pronounced the phoneme longer than the native speakers with more open mouths but with less loudness. The formant analysis showed that F1 values of the Japanese /t/ pronounced by Japanese major group were lower than those of the non-major. Its F2 values by the major group were higher than those of the non-major, which would suggest that the Koreans produced the tongue blade in more frontal position than the native speakers.

• Journal of Applied Reliability
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• v.17 no.1
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• pp.1-10
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• 2017

Purpose: This study aims at omitting the initial testing of the ASRP by determining the initial test year. Methods: This study is to determine of the initial test year for one-shot system using validity assessment of drugs. Results: Procedures for determining the initial test duration of the one shot system and examples of omitting the tests are presented. Conclusion: Using this method, the time and labor required for testing can be saved by omitting the initial testing of ASRP.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.6
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• pp.865-873
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• 2019

Objective: The study was designed to investigate the effects of restraint method, restraint duration, and body weight on stress-linked hormones (corticosterone, adrenaline, and noradrenaline), blood biochemical (namely glucose and lactate), and the meat quality in broiler chickens. Methods: A total of 120 male broiler chickens (Cobb 500) were assigned to a $2{\times}3{\times}2$ factorial arrangement in a completely randomized design using two restraint methods (shackle and cone), three durations of restraint (10, 30, and 60 s), and two categories of live body weight ($1.8{\pm}0.1kg$ as lightweight and $2.8{\pm}0.1kg$ as heavyweight). Results: Irrespective of the duration of restraint and body weight, the coned chickens were found to have lower plasma corticosterone (p<0.01), lactate (p<0.001), lower meat drip loss (p<0.01), cooking loss (p<0.05), and higher blood loss (p<0.05) compared with their shackled counterparts. The duration of restraint had significant effects on the meat initial pH (p<0.05), ultimate pH (p<0.05), and yellowness (p<0.01). The lightweight broilers exhibited higher (p<0.001) blood loss and lower (p<0.05) cooking loss compared to the heavyweight broilers, regardless of the restraint method used and the duration of restraint. However, the interaction between the restraint method, duration of restraint, and body weight contributed to differences in pre-slaughter stress and meat quality. Therefore, the interaction between the restraint method and the duration of restraint affected the meat shear force, lightness ($L^*$) and redness ($a^*$). Conclusion: The duration of restraint and body weight undoubtedly affect stress responses and meat quality of broiler chickens. Regardless of the duration of restraint and body weight, the cone restraint resulted in notably lower stress, lower meat water loss, and higher blood loss compared to shackling. Overall, the findings of this study showed that restraint method, duration of restraint, and body weight may affect the stress response and meat quality parameters in broilers and should be considered independently or interactively in future studies.