This paper discusses the influence of transverse reinforcement spacing and support width of concrete wide beam on shear performance. In order to evaluate the shear performance, a total of thirteen specimens were constructed and tested. The transverse reinforcement spacing, the number of legs and support width were considered as variables. From the test results, the shear strength equation of concrete wide beam is proposed for prediction of shear strength of concrete wide beam to consider the transverse reinforcement spacing and support width. It is shown that the proposed equation is able to predict shear strength reasonably well for concrete wide beam.

본 연구는 우리나라의 전체 국유림에 대한 경영이력 및 경영계획정보가 구축되어 있는 국유림경영정 보시스템이 관련 법령(국유림경영계획 작성 및 운영요령)의 변경에 따라, 개정 전에는 평균 흉고직경 값만 입력하도록 구축되어 있으나 개정 후에는 평균 흉고직경, 최저·최고 흉고직경값으로 표기하는 것으로 변경되었다. 이와 관련하여 기 구축되어 있는 모든 흉고직경값을 최저·최고 흉고직경값으로 변환 할 수 있는 추정 알고리즘이 필요하다. 따라서 본 연구는 국유림경영정보시스템에 포함되어 있는 12개 주요 수종에 대한 최저·최고 흉고직경을 자동으로 표기할 수 있는 추정식을 개발하기 위해 수행하였다. 최저·최고 흉고직경 추정식을 개발하기 위하여 제5∼6차(2006∼2015년) 국가산림자원조사(National Forest Inventory, NFI)의 6,858개 고정표본점 자료를 이용하였다. 최저·최고 흉고직경 추정식 도출을 위하여 흉고직경, 임령, 수고의 3가지 생장변수를 이용한 흉고직경-임령, 흉고직경-수고의 2가지 추정모형을 적용하였다. 본 연구에서 가장 적합한 최저·최고 흉고직경 추정모형은 흉고직경과 수고 변수를 이용한 추정식 Dmin=a+bD+cH, Dmax=a+bD+cH으로 나타났으며, 12개의 주요 수종의 최소 최대 흉고직경 추정식을 개발하였다.

This paper presents the theoretical analysis for the flow driven by surface tension and gravity force in an inclined circular tube. The previously developing equation for Power-Law model is a simple ordinary differential type. A governing equation is developed for describing the displacement of a non-Newtonian fluid(Casson model) that continuously flows into a circular tube by surface tension, which represents a second-order, nonlinear, non-homogeneous, and ordinary differential form. It was found that the theoretical predictions of the governing equation were in good agreement with the results for considering the Newtonian model.

Water resources are the most important resources for all living things on the earth to grow and reproduce, and sustain agricultural, industrial, household, recreational and environmental activities. Since 97% of these water resources is a seawater, desalination is a practical choice of many water-poor countries. Currently MSF (multistage flash evaporation) and RO (reverse osmosis) that need 25 kWh and 4kWh per m3 of fresh water although thermal methods need 718kWh and pressure based-RO 1kWh. This work focuses on how to estimate highest osmotic pressure of many aqueous saturated solutions such as NaCl and fuel ethanol that reaches 343.07 bars of 26.47%, over 5000 bars, respectively. This work shows that Lewis equation (1908) fits within 10% of OLI pressure and the modified estimation of Chang (1983) within 1% accuracy.

An elliptic blending Reynolds stress transport equation model for Newtonian fluids has been extended to predict polymer-induced drag reduction FENE-P fluids. The conformation tensor equation which is related to the polymer stress is adopted from the model form of Resende et al., and the models of redistribution and dissipation rate terms for the Reynolds stress transport equation are considered by the elliptic blending equation. Also, the new model terms for viscoelastic turbulent transport and viscoelastic dissipation in the Reynolds stress transport equation are introduced to consider the polymer additives effect. The prediction results are directly compared to the DNS data to assess the performance of the present model predictions.

The purpose is to identify the impacts of internal and external integrations in an automotive supply chain in Thailand. Data are collected from automotive firms in Thailand and are analyzed using structural equation modeling (SEM). The result indicates that both internal and external integrations are significant factors affecting market flexibility.

Nodal transport methods are proposed for solving the simplified even-parity neutron transport (SEP) equation. These new methods are attributed to the success of existing nodal diffusion methods such as the Polynomial Expansion Nodal and the Analytic Function Expansion Nodal Methods, which are known to be very effective for solving the neutron diffusion equation. Numerical results show that the simplified even-parity transport equation is a valid approximation to the transport equation and that the two nodal methods developed in this study also work for the SEP transport equation, without conflict. Since accuracy of methods is easily increased by adding node unknowns, the proposed methods will be effective for coarse mesh calculation and this will also lead to computation efficiency.

PURPOSES: This study is to estimate nondestructive strength equation based on probability for bridges using field test data. METHODS: In this study, a series of the field inspection and the test have been performed on 297 existing bridges, in order to evaluate the bridges, based on the test results of the in-depth inspection, and the estimated strengths by means of the nondestructive strength equations are analyzed and compared with results of the core specimen strengths. RESULTS: According to results of analyses, In case of standard design compressive strength of concrete is 18MPa, 21MPa, similar reliability of RILEM equation were 0.89~0.90, but in case of standard design compressive strength of concrete is 35MPa, 40MPa were 0.4~0.56. According to standard design compressive strength of concrete is 40MPa, similar reliability of ultrasonic pulse velocity method equation were 0.56. CONCLUSIONS: RILEM equation had high similar reliability than other equation in case of standard design compressive strength of concrete is 18MPa, 21MPa, but had low similar reliability than other equation in case of standard design compressive strength of concrete is 35MPa, 40MPa. and ultrasonic pulse velocity method equation had low similar reliability than other equation in case of standard design compressive strength of concrete is 40MPa.

본 연구의 목적은 위성의 밝기온도를 기반으로 한 정량적 강우량 추정기법의 개선을 위함이다. 우리나라 여름철 강우사례를 이용하여 강우추정을 위한 비선형 관계식을 개선하였다. 분석을 위해 레이더 자료로 기상청 기상레이더 관측망의 고도 1.5 km와 CMAX 반사도 합성자료를 사용하였으며, 위성자료는 천리안 위성의 가시, 적외, 수증기 채널의 자료를 이용하였다. 새롭게 도출된 알고리즘은 A-E method, CRR v4.0 analytic function의 결과와 비교를 하였다. 검증을 위해 우리나라 ASOS에서 관측한 지상강우량 자료를 사용하였다. 공간검증을 위해 검증지수로 POD, FAR, CSI를 계산하였으며 각각 0.67, 0.76, 0.21로 나타났다. 정량적 강우검증을 위해 MAE와 RMSE를 계산하였으며 각각 2.49, 6.18 mm/h였다. A-E에 비하여 정량적인 오차가 줄어들었으며 CRR에 비하여 공간적인 정확도가 증가하였다. 개선한 관계식을 적용한 방법이 두 알고리즘의 부족한 부분을 보완할 수 있는 것으로 판단된다. 개선한 관계식을 통해 강우를 추정하는 방법은 복잡한 알고리즘을 거치지 않고 짧은 시간에 강우추정이 가능함으로써 현업용 실시간 초단기 예보에 활용될 수 있다.

The purpose of this study is to develop correction formulas using the results of measurement by PMS 103, which is a weight method measuring device, and by Dusttrak (TSI, USA), DustMate (Turnkey Instrument Ltd., UK), and LD-5 (SIBATA, Japan), which are light scattering measuring devices. The objective is to evaluate and identify new standards (to develop a proposal) in order to complement the limitations of the existing measurement methods of public transportation vehicle indoor air quality by utilizing the three nephelometer type measuring devices. In the case of non-rush hours, the PMS values were estimated using an estimation regression equation. Statistically, the PMS values that were actually measured were not significantly different (p-value=0.4375, 0.4375, 1.000). With respect to the agreement between the two values, ICC was 0.99 in the case of the estimation regression equation using LD-5 values, 0.97 in the case of the estimation regression equation using Dusttrak values, and 0.84 in the case of the estimation regression equation using DustMate values to allow for the identification of agreement at greater levels. In the case of rush hours, the PMS values were estimated using an estimation regression equation. Statistically, the PMS values that were actually measured were not significantly different (p-value=0.3125, 0.6250, 0.8125). With respect to the agreement between the two values, ICC was 0.92 in the case of the estimation regression equation using LD-5 values, 0.91 in the case of the estimation regression equation using Dusttrak values, and 0.89 in the case of the estimation regression equation using DustMate values to allow for the identification of agreement at greater levels.

This study develops an empirical prediction equation of spectral acceleration responses of earthquakes which can induce structural damages. Ground motion records representing hazards of low-to-moderate seismic regions were selected and organized with several influential factors affecting the response spectra. The empirical equation and estimator coefficients for acceleration response spectra were then proposed using a robust nonlinear optimization coupled with a regression analysis. For analytical verification of the prediction equation, response spectra used for low-to-moderate seismic regions were estimated and the predicted results were comparatively evaluated with measured response spectra. As a result, the predicted shapes of response spectra can simulate the graphical shapes of measured data with high accuracy and most of predicted results are distributed inside range of correlation of variation (COV) of 30% from perfectly correlated lines.

This study aims to suggest the methodology to improve to estimate back-calculated fish growth parameters using weighted average. It is to contribute to correct errors in the calculation of back-calculated growth equation with unequal numbers of sample by age. If the numbers of sample were evenly collected by age, each back-calculated length at age was equal between arithmetic and weighted averages. However, most samples cannot be evenly collected by age in reality because of different catchability by fishing gear and limitation of environment condition. Therefore, the estimation of back-calculated length by weighted average method is essential to calculate growth parameters. There were some published growth equations from back-calculated length using a simple arithmetic average with different numbers of samples by age when searching for back-calculated growth equations from 91 relevant papers. In this study, the process of deriving growth equation was investigated and two different average calculations were applied to a fish growth equation, for example of Acheilognathus signifer. Growth parameters, such as L∞, k and t0, were estimated from two different back-calculated averages and the growth equations were compared with growth performance index. Based on the correction of back-calculated length using weighted average by age, the changes by female and male were -14.19% and -5.23% for L∞, and 59.28% and 18.91% for k, respectively. The corrected growth performance index by weighted average improved at 7.05% and 2.46% by female and male, respectively, compared to the arithmetic averages.

PURPOSES : The objective of this study is to develop a simple regression model in designing the asphalt concrete (AC) overlay thickness using the Mechanistic-empirical pavement design guide (MEPDG) program. METHODS: To establish the AC overlay design equation, multiple regression analyses were performed based on the synthetic database for AC thickness design, which was generated using the MEPDG program. The climate in Seoul city, a modified Hirsh model for determining dynamic modulus of asphalt material, and a new damaged master curve approach were used in this study. Meanwhile, the proposed rutting model developed in Seoul city was then used to calibrate the rutting model in the MEPDG program. The AC overlay design equation is a function of the total AC thickness, the ratio of AC overlay thickness and existing AC thickness, the ratio of existing AC modulus and AC overlay modulus, the subgrade condition, and the annual average daily truck traffic (AADTT). RESULTS: The regression model was verified by comparing the predicted AC thickness, the AADTT from the model and the MEPDG. The regression model shows a correlation coefficient of 0.98 in determining the AC thickness and 0.97 in determining AADTT. In addition, the data in Seoul city was used to validate the regression model. The result shows that correlation coefficient between the predicted and measured AADTT is 0.64. This indicates that the current model is more accuracy than the previous study which showed a correlation coefficient of 0.427. CONCLUSIONS: The high correlation coefficient values indicate that the regression equations can predict the AC thickness accurately.

The Kingery-Bulmash equation is the most common equation to calculate blast load. However, the Kingery-Bulmash equation is complicated. In this paper, a modified equation for surface blast load is proposed. The equation is based on Kingery-Bulmash equation. The proposed equation requires a brief calculation process, and the number of coefficients is reduced under 5. As a result, each parameter obtained by using the modified equation has less than 1% of error range comparing with the result by using Kingery-Bulmash equation. The modified equation may replace the original equation with brief process to calculate.

PURPOSES :This study evaluates the reasonableness of the recommended amount of deicing chemicals based on historical data for snow removal. The result can be used to aid decision-making for the reservation of cost-effective de-icing chemicals.METHODS :First, the recommended amount of de-icing chemical to use and historical usage data were evaluated to identify specific usage characteristics for each region. Road maintenance length and snow-removal working days were analyzed over the past five winter seasons. Next, differences in the recommended amount of chemical to use and actual use were compared using the Kolmogorov-Smirnov test. Last, the two types of data were analyzed using a chi-square test to verify if the two distributions of variation pattern are statistically significant. We found that there are significant differences between the data from each region during the past five winter seasons.RESULTS :The results showed that the equation for calculating the amount of de-icing chemical to use appears to be revised.CONCLUSIONS :The results imply that the equation for calculating the amount of de-icing chemical to apply as a national standard is very important when the public agency makes decisions related to snow-removal.

This paper is concerned with a test method that can be used to investigate the parameters of the Johnson-Cook constitutive model. These parameters are essential for accurately analyzing material behavior under impact loading conditions in numerical simulation. Ti-6Al-4V alloy (HCP crytal structure) was used as a specimen for the experiments. In the 10−3-103/ s strain rate range, three types of experimental methods (convention, compression and tension) were employed to compare the differences using MTS-810, SHPB and SHTB. Finite element analysis results when applying these parameters were displayed along with the experiment results.

The blast load is classified into free-air blast and surface blast following the location of explosion and surface. In this paper, several equations for blast load calculation are explained briefly and a modified equation for free-air blast load is suggested. The modified equation is based on Kingery-Bulmash equation which is used in UFC 3-340-02 and Conwep model. In this modified equation, the process of calculation is simplified against the original equation, and the number of coefficients is reduced under 5. As a result, each parameter of estimated data by modified equation has less than 1% of error range comparing with Kingery-Bulmash equation.

Coupling beams serve as primary source of energy dissipation in coupled shear wall systems during large earthquakes. However, the overestimation of the shear strength of diagonally reinforced coupling beams may be adverse effect on the seismic performance of coupled shear wall systems. In order to force coupling beams to properly work during earthquakes, coupling beams should be designed with accurate shear strength equations. The objective of this study is to propose the accurate shear strength equation for slender diagonally reinforced coupling beams. For this purpose, experimental tests were conducted using three diagonally reinforced coupling specimens with different amount of transverse reinforcement under reversed cyclic loads to evaluate the hysteretic behavior of the specimens. The test results show that transverse reinforcement of slender diagonally reinforced coupling beam affects the maximum strength and drift ratio.

본 연구에서는 유한한 깊이의 투수층에 의한 파랑 감쇠 현상을 흐름함수에 대한 확장형 완경사방정식을 사용하여 해석하였다. 에너지 감쇠율을 흐름함수에 대한 완경사방정식에 고려할 수 있도록 감쇠항을 제시하였다. 수치실험 시 계산영역에서 반사된 파가 경계에서 재반사되는 문제를 극복하기 위해서, 델타함수 형태의 원천함수를 유도하여 계산영역 내에서 조파하였다. 경사면 위의 파랑의 반사율 측정 실험을 다양한 주기에 대해서 수행하였다. 투수성이 있는 수중둔덕에 대해서, 수치실험 결과는 해석해인 적분방정식의 결과와 대체로 잘 일치하였다. 그러나, 투수계수가 크고 파장이 길수록 본 연구의 결과가 상대적으로 높은 투과율을 보였다.