• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.167-180
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• 2019

Friction piles are being constructed in Southeast Asia (Myanmar, Cambodia, Vietnam, etc.) where the soft ground is deep, and many cases of friction piles are accumulated in terms of experience. In this study, we used the results of four static load test and load transfer test conducted in Myanmar sites to analyze the skin friction of soil layer. In addition, we proposed a relationship chart with skin friction measured in the N-value of Standard Penetration Test (SPT) and the load transfer test result of the single drilled shaft. In the case of Myanmar sites, the range of soil layers was deeper than domestic sites, so the conventional formula of skin friction using the N-value of SPT is different from domestic sites. In sandy layer, fs = 0.096 N in Myanmar sites showed a similar result of the domestic fs = 0.106 N. In clayey layer, fs = 0.315 N, in Myanmar sites showed about 5.0 times higher than the domestic fs = 0.062 N. The results of this study are based on limited data. Therefore, if we analyze the results of more load transfer tests, we can suggest a conventional formula for skin friction according to the N-value. It is expected to be used as important basic data in the future.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.511-518
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• 1998

In order to develop the aerosol bolus technique which is thought to be a potential tool for probing geometries or abnormalities of small airways, an experimental system of measuring fast time variations of particle concentration in the inhaled and exhaled breathing air was developed. The system generates monodisperse sebacic acrid particles of 1 micron size and 1.2 of geometric standard deviation in high concentration of $10^8$ particles/cc, delivers a short pulse of particles at the controlled instant during inhalation using a solenoid valve, and measures the fast change of particle concentration in using the laser light scattering. Successful operation of the generator and the measuring system was confirmed by smooth concentration profiles in inhalation. It was also confirmed that maintaining a constant breathing rate is essential to stable outputs and any disturbance in flow rate near the mode (maximum concentration) induces a large number of spurious peaks in the exhalation. Experimental data without strict control of breathing flow rate showed a substantial amount of scatter. The measured results showed an improvement in scatter over the existing results. When compared with theoretical predictions from 1-D convective diffusion equation and other experiments, general characteristics of dispersion for several penetration depths showed a good agreement, but there exists some difference in absolute values, which is attributed to the difference in body conditions. Improvements are needed in the theory, especially in relation to correcting for the effect of breathing flow rate.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.69-76
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• 2007

The accumulation curves of phenol in the flesh of apples were measured at $5^{\circ}C$, $25^{\circ}C$ and $40^{\circ}C$ when they were exposed to phenol vapor, The effective diffusivities of phenol at the rind and flesh were determined by comparing its experimentally obtained accumulation curves with simulated ones. The simulation was carried out by the non-steady state diffusion rate equation. The diffusion model assumed the consecutive diffusion of phenol at the rind and flesh of apples. The detection time of phenol in the flesh of apples was shortened with increasing temperature, and it accumulated amount also increased rapidly. The estimated effective diffusivity of phenol at the rind of apples increased with temperature as like $1.1{\times}10^{-13}\;m^2/s$ at $5^{\circ}C$, $1.4{\times}10^{-13}\;m^2/s$ at $25^{\circ}C$ and $2.2{\times}10^{-13}\;m^2/s$ at $40^{\circ}C$, but those at the flesh of apples were invariant as $1.5{\times}10^{-10}\;m^2/s$ at this temperature range. The effect of temperature on the diffusivity of phenol was small, but the increase of the vapor pressure of phenol with temperature accelerated the penetration of phenol at the rind, resulting in the rapid accumulation at the flesh of apple.

• Journal of Distribution Science
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• v.11 no.10
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• pp.37-45
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• 2013

Purpose - Appropriate response to the fast changing economic environment determines SMEs' competiveness in the era of globalization and open market and, therefore, government policies to strengthen SME's competitiveness will be very important in the future. It is time to investigate the element of strategic orientation that is necessary for strengthening the competitiveness of SMEs, and its effect on the success of a business start-up. This study analyzes the network orientation in addition to existing strategic orientation, and focuses on price and quality management capability as mediators for strategic orientation and outcomes of business start-ups. Research design/data/methodology - The orientations of technology-based business founders were classified into market, technology, network, and entrepreneurial orientation. We then investigated the effect of these orientations on product price and quality management capability, as well as the influence of price and quality management capability on the outcome of a business start-up. This study is based on the nation-wide survey of the founders and members of technology-based business establishments. The survey was administered to 300 selected companies via email for a period of one month, at the end of which 175 companies replied with valid answers. Further, for effective and objective research, we used SPSS 14.0 and Amos 7.0 for structural equation modeling assumptions and hypothesis verification. Results - Except for entrepreneurial orientation, the other three orientations, namely, technology, market, and network orientations, affect the price management capability according to our results. The price management capability relates significantly with the sales and customer satisfaction. Especially, technology orientation is the core competency of start-ups that affects price and quality management capabilities. However, technology and entrepreneurial orientation do not influence the outcome of business start-ups, but affect their quality management capabilities. Conclusions - This study confirms that the strategic orientation affects product price as well as quality management capabilities, to introduce new products and achieve successful outcomes. In conclusion, new business founders face the dilemma of trade-off between price and quality in the planning stage of new product development. In particular, price management capability directly affects the outcome. Therefore, price management is more important for a successful start-up than quality management. Especially, during the initial stages of starting up a new business, price management capability entails following the market-leading company, or price penetration strategy. In this stage, price management is dependent on the information from outside rather than on the founder's decision, and it directly affects sales performance and customer satisfaction. In contrast, quality management capability is directly related to the technology capability and market experience of founders. In this case, subjective and proactive decision making is required for differentiation and development of demand in the niche market, which does not directly influence the sales performance and customer satisfaction.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.149-158
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• 1998

The SAR patterns of biological objects contacted with coaxial waveguide antennal has been investigated, in which the biological object was modeled by a homogeneous and four-layered lossy human body. We derived the finite-difference time-domain(FDTD) algorithm and equation of MUR and generalized perfectly matched layer(GPML) ABCs in cylindrical coordination. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of MUR and GPML ABCs in the FDTD method to obtain the absorbed power patterns in the media. The specific absorption rates (SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in the FDTD method. The SAR patterns of the FDTD method using MUR absorbing boundary conditions(ABCs) was compared with those of the FDTD method using GPML ABCs. The comparison exhibits that the penetration depth of the SAR patterns using MUR ABCs is deeper than that of the SAR patterns using GPML ABCs because of loss in free space. However, the spread in the lateral directions of the SAR patterns using GPML ABCs is smaller than of the SAR patterns using MUR ABCs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.197-203
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• 2002

The estimation of pile bearing capacity is important since the design details are determined from the result. There are numerous ways of determining the pile design load, but only few of them are chosen in the actual design. According to the recent investigation in Korea, the formulas proposed by Meyerhof based on the SPT N values are most frequently chosen in the design stage. In the study, various static and dynamic formulas have been used in predicting the allowable bearing capacity of a pile. Further, the reliability of these formulas has been verified by comparing the perdicted values with the static and dynamic load test measurements. Also in cases, these methods of pile bearing capacity determination do not take the time effect consideration, the actual allowable load as determined from pile load test indicates severe deviation from the design value. The principle results of this study are summarized as follows : A a result of estimate the reliability in criterion of the Davisson method, in was showed that Terzaghi & Peck > Chin > Meyerhof > Modified Meyerhof method was the most reliable method for the prediction of bearing capacity. Comparisons of the various pile-driving formulas showed that Modified Engineering News was the most reliable method. However, a significant error happened between dynamic bearing capacity equation was judged that uncertainty of hammer efficiency, characteristics of variable , time effect etc... was not considered. As a result of considering time effect increased skin friction capacity higher than end bearing capacity. It was found out that it would be possible to increase the skin friction capacity 1.99 times higher than a driving. As a result of considering 7 day's time effect, it was obtained that Engineering News. Modified Engineering News. Hiley, Danish, Gates, CAPWAP(CAse Pile Wave Analysis Program ) analysis for relation, respectively, $Q_{u(Restrike)}$ $Q_{u(EOID)}$ = 0.971 $t_{0.1}$, 0.968 $t_{0.1}$, 1.192 $t_{0.1}$, 0.88 $t_{0.1}$, 0.889 $t_{0.1}$, 0.966 $t_{0.1}$, 0.889 $t_{0.1}$, 0.966 $t_{0.1}$

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.433-439
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• 2011

The frost depth(frost penetration) is used to install anti-frost heave layers in pavement designs. The freezing index is calculated by an annual accumulated value of multiplying the period of time with temperatures below zero, and the corresponding temperature. Therefore, the DAAT(daily average air temperature) calculation method may play an effect on the FI(freezing index). The Weather Observatory used to supply 4 average air temperatures per day, but currently supplies 8 per day. With this study, we divided the southern part(below FI=$350^{\circ}C{\cdot}day$) of the Korean peninsula into 6 areas according to site conditions(low embankment, embankment-cutting slope, and the cutting slope) and established a field measurement system for 15 positions to check the effects on the result of FI according to differing DAAT calculation methods. The air temperatures obtained by the field measurement system was used to calculate and compare the FI. As a result, the freezing index calculated based on the $DAAT_4(T_4)$ is normally greater by 3% than the one on $DAAT_8(T_8)$. In addition, the calibration equation for the freezing index using air temperatures was proposed through the research.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.169-177
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• 2018

Glass fiber reinforced polyester (GFRP) composites are widely used as structural materials in harsh environment such as underground pipes, tanks and boat hulls, which requires long-term water resistance. Especially, these materials might be damaged due to delamination between gelcoat and composites through an osmotic process when they are immersed in water. In this study, GFRP laminates were prepared by surface treatment of UPE (unsaturated polyester) gelcoat by vacuum infusion process to improve the durability of composite materials used in underground pipes. The composite surface coated with gelcoat was examined for surface defects, cracking, and hardness change characteristics in water-immersion environments (different temperatures of $60^{\circ}C$, $75^{\circ}C$, and $85^{\circ}C$). The penetration depth of cracks was investigated by micro CT imaging according to water immersion temperature. It was confirmed that cracks developed into the composites material at $75^{\circ}C$ and $85^{\circ}C$ causing loss of durability of the materials. The point at which the initial crack initiated was defined as the failure time and the life expectancy at $23^{\circ}C$ was measured using the Arrhenius equation. The results from this study is expected to be applied to reliability evaluation of various industrial fields where gelcoat is applied such as civil engineering, construction, and marine industry.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.288-299
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• 1996

This is the basic study to investigate the amount of transpirational water loss in thrifty mature Quercus mongolica stand by the heat pulse method. The differences of heat pulse velocity by direction and depth, differences of heat pulse velocity by dominant, codominant and suppressed trees, diurnal changes of heat pulse velocity due to the change of leaf water potential, vapor pressure deficit and radiation, and sap flow path way in sapwood by dye penetration were measured in stems. Finally the amounts of daily and annual transpiration in stand were calculated by the heat pulse velocity. The results obtained were summarized as follows : 1. Relationship between heat pulse velocity(V) and sap flow rate(SFR) was obtained as a equation of SFR=1.37V. 2. The sap flow rate was high in the order of dominant, codominant, and suppressed trees. The daily heat pulse velocity changed with radiation, temperature and vapor pressure deficit. 3. The heat pulse velocity showed the similar diurnal variation as the leaf water potential change. 4. The heat pulse velocity showed the highest value in May(4.0cm/hr in average), the lowest one in July(2.9cm/hr in average). 5. The heat pulse velocity in the same stem presented the highest value in the northern direction, medium in western, and the lowest in southern and eastern. 6. The heat pulse velocity in stem was highest in 0.5cm, medium in 1.0cm, and lowest in 1.5cm depth from the surface of stem. 7. The sap flow path way in stem showed sectorial straight ascent pattern in four sample trees. 8. The amount of sap flow(SF) was presented as a equation of $SF=1.37A{\cdot}V$(A: the cross-sectional area of sapwood, V: heat pulse velocity), and especially SF was larger in dominant tree than codominant and suppressed trees. 9. The amount of daily transpiration was 5.6ton/ha/day, and its composition ratio was 72% at day and 28% at night. 10. The amount of stand transpiration per month was largest in May(168ton/ha/month), lowest in July(125ton/ha/month). The amount of stand transpiration per year was 839ton/ha/year.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.152-165
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• 1993

This is the basic study in order to know the amount of transpirational water loss in a Larix leptorepis stand by a heat pulse method. Especially this study has been measured and discussed the diurnal and seasonal trends of heat pulse velocity by changes of radiation, temperature and humidity, differences of heat pulse velocity by direction and depth in stem, differences of heat pulse velocity by dominant, codominant and suppressed trees, diurnal change of heat pulse velocity by change of leaf water potential, sap flow path way in sapwood by dye penetration and amount of daily and annual transpiration in a tree and stand. The results obtained as follows : 1. Relation between heat pulse velocity(V) and sap flow rate(SFR) was established as a equation of SFR=1.37V($r=0.96^{**}$). 2. The sap flow rate presented in the order of dominant, codominant and suppressed tree, respectively. The daily heat pulse velocity was changed by radiation, temperature and vapor pressure deficit. 3. The heat pulse velocity in individual trees did not differ in early morning and in late night, but had some differed from 12 to 16 hours when radiation was relatively high. 4. The heat pulse velocity and leaf water potential showed similar diurnal variation. 5. The seasonal variation of heat pulse velocity was highest in August, but lowest in October and similar value of heat pulse velocity in the other months. 6. The heat pulse velocity in stem by direction was highest in eastern, but lowest in southern and similar velocity in western and northern. 7. The difference of heat pulse velocity in according to depths was highest in 2.0cm depth, medium in 1.0cm depth, and lowest in 3.0cm depth from surface of stem. 8. The sap flow path way in stem showed spiral ascent turning right pattern in five sample trees, especially showed little spiral ascent turning right in lower part than 3m hight above ground, but very speedy in higher than 3m hight. 9. The amount of sap flow(SF) was presented as a equation of SF=1.37AV and especially SF in dominant tree was larger than in codominant or suppressed tree. 10. The amount of daily transpiration was 30.8ton/ha/day and its composition ratio was 83% at day and 17% at night. 11. The amount of stand transpiration per month was largest in August(1,194ton/ha/month), lowest in May (386ton/ha/month). The amount of stand transpiration per year was 3,983ton/ha/year.