• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.468-477
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• 2019

The numerical model of Boussinesq approximation, which is mainly used for evaluating the port calmness due to the irregular waves, has a limit of applicability of lattice size in ports such as marinas with narrow port openings of around 30m. The SWASH model controls the partial reflection according to the depth, porosity coefficient and structure size when applying the reflected wave incident on the structure and terrain. In this study, the partial reflection evaluation at the front of the structure according to the bottom shape and the shape of the structure are examined. In order to evaluate the reproducibility of the model due to the diffraction waves entering the term, the area of incidence at right angles and inclination of the structure is constructed and compared with the diffraction theory suggested by Goda et al. (1978). The experimental results of the sectional structure reflectances calculated as the depth mean show reflectances similar to the approximate values of the reflectances presented by Stelling and Ahrens (1981). It is considered that the reflected wave is well reproduced according to the control of the reflected wave at the boundary and the shape and topography of the structure. Compared with previous studies to examine the diffraction of the wave incident from the breakwater opening, the wave incidence angle and the shape of the diffraction wave are very similar to the theoretical values, but both oblique and rectangular incidence In the case where the direction concentration is small, the diffraction degree is underestimated in some sections with the crest ratio of 0.5 to 0.6.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.679-690
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• 2015

The need to remove the cause of traffic accidents by improving the engineering system for a vehicle and the road in order to minimize the accident hazard. This is likely to cause traffic accident continue to take a large and significant social cost and time to improve the reliability and efficiency of this generally poor road, thereby generating a lot of damage to the national traffic accident caused by improper environmental factors. In order to minimize damage from traffic accidents, the cause of accidents must be eliminated through technological improvements of vehicles and road systems. Generally, it is highly probable that traffic accident occurs more often on roads that lack safety measures, and can only be improved with tremendous time and costs. In particular, traffic accidents at intersections are on the rise due to inappropriate environmental factors, and are causing great losses for the nation as a whole. This study aims to present safety countermeasures against the cause of accidents by developing an intersection Traffic safety evaluation model. It will also diagnose vulnerable traffic points through BPA (Back -propagation algorithm) among artificial neural networks recently investigated in the area of artificial intelligence. Furthermore, it aims to pursue a more efficient traffic safety improvement project in terms of operating signalized intersections and establishing traffic safety policies. As a result of conducting this study, the mean square error approximate between the predicted values and actual measured values of traffic accidents derived from the BPA is estimated to be 3.89. It appeared that the BPA appeared to have excellent traffic safety evaluating abilities compared to the multiple regression model. In other words, The BPA can be effectively utilized in diagnosing and practical establishing transportation policy in the safety of actual signalized intersections.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.3-12
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• 2006

The behavior of concrete structures subject to fire is complex, depending on many factors. The factors usually considered in research include the level and endurance of temperatures in concrete and reinforcing bars, the mechanical properties of the steel and concrete, moisture contents, cover thickness, existence of eccentricity, and member geometry among others. Although there are a few sophisticated numerical models which can trace the effects of these important parameters on the residual capacity of reinforced concrete columns damaged by fire, practical predictive formulas are in need for rapid yet reasonable assessment in practice. The practical formulas are developed in this study for fire-damaged normal strength reinforced concrete square columns, which can approximate the predictions of those sophisticated numerical models with ease in use. The formulas take into account the effects of exposure time to fire, concrete strength, reinforcement ratio and sectional area. The developed formulas are seen to correlate with the predictions of numerical model in a reasonable agreement. Some examples are also presented in determining the residual strength, safety and additionally needed strengths for a fire-damaged reinforced concrete column.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.69-84
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• 1997

We consider a linear calibration problem, $y_i = $$\alpha + \beta (x_i - x_0) + \epsilon_i$, $i=1, 2, {\cdot}{\cdot},n$ $y_f = \alpha + \beta (x_f - x_0) + \epsilon, $ where we observe $(x_i, y_i)$'s for the controlled calibration experiments and later we make inference about $x_f$ from a new observation $y_f$. The objective of the calibration design problem is to find the optimal design $x = (x_i, \cdots, x_n$ that gives the best estimates for $x_f$. We compare Kim(1989)'s Bayesian design which minimizes the expected value of the posterior variance of $x_f$ and some optimal designs from literature. Kim suggested the Bayesian optimal design based on the analysis of the characteristics of the expected loss function and numerical must be equal to the prior mean and that the sum of squares be as large as possible. The designs to be compared are (1) Buonaccorsi(1986)'s AV optimal design that minimizes the average asymptotic variance of the classical estimators, (2) D-optimal and A-optimal design for the linear regression model that optimize some functions of $M(x) = \sum x_i x_i'$, and (3) Hunter & Lamboy (1981)'s reference design from their paper. In order to compare the designs which are optimal in some sense, we consider two criteria. First, we compare them by the expected posterior variance criterion and secondly, we perform the Monte Carlo simulation to obtain the HPD intervals and compare the lengths of them. If the prior mean of $x_f$ is at the center of the finite design interval, then the Bayesian, AV optimal, D-optimal and A-optimal designs are indentical and they are equally weighted end-point design. However if the prior mean is not at the center, then they are not expected to be identical.In this case, we demonstrate that the almost Bayesian-optimal design was slightly better than the approximate AV optimal design. We also investigate the effects of the prior variance of the parameters and solution for the case when the number of experiments is odd.

• Journal of Korean Society of Steel Construction
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• v.22 no.6
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• pp.553-561
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• 2010

The purpose of this paper is to analytically find the approximate supplement damping ratio of the viscous damper installed in self-centering (SC) single-degree-of-freedom (SDOF) systems with maximum displacements that are similar to those of elasto-plastic (EP) SDOF systems. The behavior of an SC SDOF system under harmonic cyclic loading was first described. Then an analytical model that can capture the behavior of the viscously damped SC SDOF system was introduced. Analysis parameters that characterize the hysteresis of the EP and SC SDOF systems were chosen, and nonlinear time-history analyses were performed using 20 historical accelerograms. Most of the SC SDOF systems with viscous dampers with approximately 10-15% damping ratios presented mean maximum displacement values that were similar to those of the EP SDOF systems. To investigate in detail the seismic performance of both systems, three EP SDOF systems and six corresponding SC SDOF systems were selected. The analyses showed that all the SC SDOF systems eliminated the residual displacements after the end of their shaking, and that the SC SDOF systems with 15% damping ratios performed better than the EP SDOF systems in terms of maximum displacement and acceleration response.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.650-656
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• 2012

The aims of the experiment, conducted over three years in the Central Europe field conditions, were (1) to investigate the effect of growing period (plantings in the middle and at the end of August: $1^{st}$ and $2^{nd}$ term, respectively) on yield and chemical composition of the non-heading Chinese cabbage (Brassica rapa var. chinensis) cultivars 'Taisai', 'Pak Choy White', and 'Green Fortune', and (2) to develop regression models to evaluate the changes in crop yields as a function of weather conditions. A highest marketable yield was obtained from 'Taisai' (65.71 and 77.20 $t{\cdot}ha^{-1}$), especially in the $2^{nd}$ term of production. Low yield, observed for 'Pak Choy White' was due to its premature bolting. Almost 39% ($1^{st}$ term) and 70% ($2^{nd}$ term) of plants of this cultivar formed inflorescence shoots before harvest. The highest dry matter level was observed in the leaf petioles of 'Taisai', while 'Green Fortune' was the most abundant of carotenoids and L-ascorbic acid. The content of soluble sugars was the lowest for 'Pak Choy White'. In a phase of harvest maturity, more of the analyzed constituents were gathered by plants from earlier plantings, and differences were as follows: 4.7% (dry matter), 26.3% (carotenoids) and 22.1% (L-ascorbic acid), in comparison to $2^{nd}$ term of production. Significant increase of soluble sugars level was observed for plants from later harvest. The regression model for marketable yield of Chinese cabbage cultivar 'Taisai' as a function of maximum air temperature can predict the yield with accuracy 68%. The models for yield or bolting of 'Pak Choy White', based on extreme air temperatures and sunshine duration, were more precise (98%). It should be pointed out that Taisai could be recommended for later growing period in Central Europe conditions with regard to maximum yield potential. 'Green Fortune' was notable for its uniform yielding. To obtained plants of higher nutritional value, earlier time of cultivation should be suggested. Described models can be successfully applied for an approximate simulation of Chinese cabbage yielding.

• The Korean Journal of Physiology
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• v.26 no.2
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• pp.143-150
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• 1992

The purpose of this study is to obtain the effective concentration of capsaicin to relieve pain with no change in the number of C-fibers and its effective duration for pain relief. Capsaicin has been used extremely as a experimental tool and as topical medications for acute or chronic tissue injuries and partial nerve injury is the main cause of causalgiform pain disorders in humans. Here, the left sciatic nerve was ligated unilaterally at the high level of the thigh to prepare an animal model of this pain condition. The rat developed guarding behavior of the ipsilateral hind paw within a few hours after the operation and this behavior was maintained for several months thereafter, suggesting the possibility of spontaneous pain. These animals were divided into two groups(4-week & 8-week) and each group was subdivided into five groups by different concentration (0.05, 0.1, 0.5, 1.0 & 2.0%). Each capsaicin concentration was treated locally on the spinal cord-side of the ligated nerve and the foot withdrawal latency was measured. Thereafter, the dorsal roots of L5 were removed from both sides immediately after in tracardial perfusion for the counting of C-fibers by the histological procedure. There were no significant differences in the foot-withdrawal latency and the number of C-fibers between the left side treated with 0.05% capsaicin and the right side treated with the vehicle. However, latencies of the left sides treated with 0.1, 0.5, and 1.0% capsaicin increased significantly throughout 4-6 weeks with almost no change in the number of C-fibers, and the latencies showed the trends to approach slowly to those of the conditions after operation. The latency of subgroup treated with 2.0% increased by approximate 10% more than that of the right side throughout 8 weeks, and the number of C-fibers decreased by about 30% or more These results suggest that the elevated latency with capsaicin(0.1-1.0%) treatment is due to the inhibition of impulse transmission throughout the primary afferent fiber and the data from 2.0% are due to partial destruction of C-fibers. Therefore, capsaicin concentrations from 0.1% to 1.0% are probably very effective for the treatment of causalgiform pain with almost no destruction of C-fibers.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.43-54
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• 2018

The accurate estimation of reference crop evapotranspiration ($ET_o$) is essential in irrigation water management to assess the time-dependent status of crop water use and irrigation scheduling. The importance of $ET_o$ has resulted in many direct and indirect methods to approximate its value and include pan evaporation, meteorological-based estimations, lysimetry, soil moisture depletion, and soil water balance equations. Artificial neural networks (ANNs) have been intensively implemented for process-based hydrologic modeling due to their superior performance using nonlinear modeling, pattern recognition, and classification. This study adapted two well-known ANN algorithms, Backpropagation neural network (BPNN) and Generalized regression neural network (GRNN), to evaluate their capability to accurately predict $ET_o$ using daily meteorological data. All data were obtained from two automated weather stations (Chupungryeong and Jangsu) located in the Yeongdong-gun (2002-2017) and Jangsu-gun (1988-2017), respectively. Daily $ET_o$ was calculated using the Penman-Monteith equation as the benchmark method. These calculated values of $ET_o$ and corresponding meteorological data were separated into training, validation and test datasets. The performance of each ANN algorithm was evaluated against $ET_o$ calculated from the benchmark method and multiple linear regression (MLR) model. The overall results showed that the BPNN algorithm performed best followed by the MLR and GRNN in a statistical sense and this could contribute to provide valuable information to farmers, water managers and policy makers for effective agricultural water governance.

• Journal of Intelligence and Information Systems
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• v.12 no.3
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• pp.15-32
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• 2006

The increasing complexity of the socio-economic environments makes it less and less possible for single decision-maker to consider all relevant aspects of problem. Therefore, many organizations employ groups in decision making. In this paper, we present a multiperson decision making method using fuzzy logic with linguistic quantifier when each of group members specifies imprecise judgments possibly both on performance evaluations of alternatives with respect to the multiple criteria and on the criteria. Inexact or vague preferences have appeared in the decision making literatures with a view to relaxing the burdens of preference specifications imposed to the decision-makers and thus taking into account the vagueness of human judgments. Allowing for the types of imprecise judgments in the model, however, makes more difficult a clear selection of alternative(s) that a group wants to make. So, further interactions with the decision-makers may proceed to the extent to compensate for the initial comforts of preference specifications. These interactions may not however guarantee the selection of the best alternative to implement. To circumvent this deadlock situation, we present a procedure for obtaining a satisfying solution by the use of linguistic quantifier guided aggregation which implies fuzzy majority. This is an approach to combine a prescriptive decision method via a mathematical programming and a well-established approximate solution method to aggregate multiple objects.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.79-86
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• 2005

The apparent source spectrum of the Fukuoka earthquake is estimated at the seismic basement by removing from the observed spectra at Korean seismic stations the path and site responses that were previously revealed through inversion process applied to large spectral D/B accumulated until 2004. The approximate source spectrum is also estimated by using data recorded near the epicenter from various Japanese seismic networks and compared with the Korean source spectrum. The comparison result shows that there is good agreement among source spectra estimated based on the data from seismic networks of Korea at large distances (190km