• Journal of Environmental Science International
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• v.24 no.4
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• pp.461-470
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• 2015

As hydrogeologic parameters such as hydraulic conductivity and specific yield are estimated by aquifer test, these are dependent on specific points at which field test was conducted. To overcome these site-specific limitations, a method of estimating transmissivity of aquifer using distribution features for parameters in Water table fluctuation model is newly suggested. Distribution features in reaction factor, specific yield and transmissivity having the function of pore space in aquifer are used to derive empirical equation for estimating transmissivity. From the result for applying the equation for 10 groundwater stations in Northeast Jeju Island, this equation is available for estimating transmissivity compared to the value estimated by existing equations. The estimated transmissivity ranged from 14.2 to $3,716.9m^2/day$, and its average was $821.8m^2/day$.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.513-520
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• 2002

The stability analysis of rock slope can be predicted using a suitable field data but it cannot be predicted unless suitable field data was taken. In this study, artificial neural networks theory is applied to predict plane failure that has a few data. It is well known that human brain has the advantage of handling disperse and parallel distributed data efficiently. On the basis of this fact, artificial neural networks theory was developed and has been applied to various fields of science successfully In this study, error back-propagation algorithm that is one of the teaching techniques of artificial neural networks is applied to predict plane failure. In order to verify the applicability of this model, a total of 30 field data results are used. These data are used for training the artificial neural network model and compared between the predicted and the measured. The simulation results show the potentiality of utilizing the neural networks for effective safety factor prediction of plane failure. In conclusion, the well-trained artificial neural network model could be applied to predict the plane failure stability of rock slope.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.139-143
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• 2005

The purpose of this study was to provide basic data for developing effective park management. For this, satisfaction factors and estimated model by satisfaction variables of user were analyzed through a questionnaire survey in Woraksan National Park, Korea. In the evaluation of the satisfaction, variables of the 'fee', 'lack and cleanness of facility', 'exorbitant pay', 'littering problem' were more unsatisfied than any other variables. Satisfaction factors by Factor Analysis were loaded with 'usual management'. In estimated model of satisfaction by Multiple Regression Analysis order of 'safety for recreation activities', 'parking problem', 'littering problem' were shown.

• Korean Journal of Environment and Ecology
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• v.20 no.2
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• pp.153-158
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• 2006

The purpose of this study was to provide basic data for developing the effective park management. For this, satisfaction factors and estimated model by satisfaction variables of visitors analyzed through a questionnaire survey in Weolchulsan National Park, Korea. In the evaluation of the satisfaction, variables of 'lack of visit program' was most unsatisfied, and 'lack of facility', 'charge of fee', 'lack of pamphlet & information facility' were more unsatisfied than any other variables. Satisfaction factors by Factor Analysis were loaded with 'facility management', 'usual management'. In estimated model of satisfaction by Multiple Regression Analysis showed in order of 'negative impacts of trail', 'lack of safety facility'.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.741-758
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• 2013

In this study, inelastic displacement ratios are investigated for existing systems with known lateral strength considering soil structure interaction. For this purpose, SDOF systems for period range of 0.1-3.0 s with different hysteretic behaviors are considered for a number of 18 earthquake motions recorded on soft soil. The effect of stiffness degradation on inelastic displacement ratios is investigated. The Modified Clough model is used to represent structures that exhibit significant stiffness degradation when subjected to reverse cyclic loading and the elastoplastic model is used to represent non-degrading structures. Soil structure interaction analyses are conducted by means of equivalent fixed base model effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. A new equation is proposed for inelastic displacement ratio of system with SSI with elastoplastic or degrading behavior as a function of structural period ($\tilde{T}$), strength reduction factor (R) and period lengthening ratio ($\tilde{T}$/T). The proposed equation for $\tilde{C}_R$ which takes the soil-structure interaction into account should be useful in estimating the inelastic deformation of existing structures with known lateral strength.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.12
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• pp.994-1001
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• 2007

Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in a compact heat exchanger with circular tubes and continuous plate fins. Simulation results such as air velocity and temperature distributions are presented, and heat transfer coefficients are compared with previous experimental correlations. Three models of standard and RNG $k-{\varepsilon}$, and Reynolds stress are applied for turbulence model applicability. Predicted heat transfer coefficient from the models of standard and RNG $k-{\varepsilon}$ are very close to those of the heat transfer correlations while there are relatively large difference, more than 17 percentage in the result from the Reynolds stress model. From the calculated results a correlation for Colburn j factor in the compact heat exchanger system is suggested.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.1
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• pp.59-70
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• 2010

This paper reorganized five service qualities dimensions of ski-resorts, then derived the improvement priority order of the service quality through a satisfaction measure considering the importance. There're more competitive situations to guarantee customers using the skies and snowboards is a major sports in winter season. In these competitive environments, this paper's going to propose a predominant-competitive strategies for improving the service quality of ski-resorts. This study measured the satisfaction considering the importance of service quality target on customers has an experience ski resort service quality to improve ski resort service quality. This study using Performance Model decide a priority order about a particular item improvement, then is going to present a guideline that can improve the service quality more exactly. As a result of the study the factors that is important to the customer were prime physical factor, access, assistance physical factor, staff service and assistant service, an improvement priority order were accommodation and eating-drinking facilities, waiting time of a slope and lift/gondola, entertainment/shopping facilities in the resorts, equipment rental and lift fare.

• Korean Journal of Child Studies
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• v.25 no.6
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• pp.15-34
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• 2004

This study is an attempt to develop the 'Parental Intelligence Scale', which can be applied in the parent education and counselling and provide more useful information for more appropriate interventions by evaluating the characteristics of parent's roles and strong/weak points of the parent's roles under the special situation and environments. In developing the scales, this study reviews of numbers of existing literatures, analysis of scales and tools on parent's role or attitude, collection of episodes on parent's role, validity check processes by field experts, and 2 rounds of factor analysis. The outcomes of the study are as follows; In regard of the development of Parental Intelligence Scale, 3 factors of care-giving role, management role, nurturing role were derived from the conceptual and measurement model. From these 3 factors, 8 sub-factors of empathy, encourage, enhancement, rational authoritativeness, flexibility, rejection, acceptance, control were constructed. 39 question items were derived in order to measure these sub-factors. Especially through the two rounds of factor analysis, the question items with enhanced internal consistency were derived and total cumulative variance was increased, which made theoretical model into the generalized model possible.

• Journal of Environmental Health Sciences
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• v.31 no.4 s.85
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• pp.260-265
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• 2005

Indoor air quality might be affected by source strength of indoor pollutants, ventilation rate, decay rate, outdoor level, and so on. Although technologies measuring these factors exist directly, direct measurements of all factors are not always practical in most field studies. The purpose of this study was to develop an alternative method to estimate the source strength and deposition constant by application of multiple measurements. For the total duration of 60 days, indoor and outdoor $NO_2$ concentrations every 3 days were measured in 30 houses in Seoul, Asan and Daegu. Using a compartment model by mass balance and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor (emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the source strength and deposition constant were estimated. Natural ventilation was $1.80{\pm}0.42\;ACH,\;1.11{\pm}0.50\;ACH,\;0.92{\pm}0.26\;ACH$ in Seoul, Asan and Daegu, respectively. Calculated deposition constant(K) and source strength of $NO_2,$ in this study were $0.98{\pm}0.28\;hr^{1}\;and\;16.28{\pm}7.47\;ppb/h,$ respectively.

• The Korean Journal of Emergency Medical Services
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• v.12 no.3
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• pp.129-135
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• 2008

Purpose : This study was to analyze the demand for emergency ambulance service and to characterize the factors associated with the demand. Method : The basis for the model was from the actual demand for public emergency ambulance and socioeconomic and geographic characteristics. Multiple regression analyses were done for the related characteristics of public ambulance service. Result : The model explained total demand with a high degree of accuracy : the coefficient of determination($R^2=0.96$). For the regression, the set of variables indicative of low socioeconomic status were all significant. It showed the inappropriate use of public ambulance system. Public ambulance demand increased in higher housing density, low income, male unemployment and female labor force. Conclusion : The demand for public ambulances appeared to be highly predictable, using a simple linear model employing socioeconomic variables, quality of service variables, and land use variables. Low-income families tended, to use the public ambulance system more often than higher income. Area having elderly people or children also made many calls. Estimated demand calls were stable and had a tendency to be similar incident types.