• International Journal of Highway Engineering
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• v.10 no.3
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• pp.11-18
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• 2008

In recent, lots of researches for mechanical-empirical design concept for asphalt pavement are on going. AASHTO 2002 Design Guide in USA and KPRP(Korean Pavement Research Program) in Korea are under developing. In these programs, the mechanical properties of hot mix asphalt are a key role for design and analysis. Unfortunately, there is no proper database on the mechanical properties of hot mix asphalt, such as dynamic modulus. The use of dynamic modulus has couple of good advantages which is based on temperature, traffic loading and frequency on pavement. In this research, the verification of the relationship between maximum nominal aggregate size and dynamic modulus has been carried out. Also, test specimen size effect on dynamic modulus has been conducted. Considering the limitation of laboratory testing machine in Korea, test specimen with 100mm diameter and 150mm height is recommended for dynamic modulus test. Also, as the maximum nominal aggregate size increases, the dynamic modulus of hot mix asphalt increases.

• Korean Journal of Construction Engineering and Management
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• v.25 no.3
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• pp.47-57
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• 2024

The purpose of this study was to analyze the Correlation Analysis between Awareness of the Serious Disaster and Safety Consciousness of Construction Workers under the Act on the Punishment of Serious. A survey was conducted on construction workers, construction managers, and safety managers. The results of this study were as follows; The correlation analysis conducted among the three groups indicated a significant correlation, with safety managers demonstrating the highest correlation, followed by construction managers and construction workers, and all three groups exhibited a moderate correlation. The correlation analysis conducted for the entire group also revealed a significant correlation, and as the number of participants increased, higher correlation coefficients were observed. Furthermore, to ascertain the significance of the correlation coefficients, a comparison was made between the p-value and the significance level (α). Consequently, a p-value smaller than the significance level of 0.05 was obtained, leading to the rejection of the null hypothesis and the acceptance of the alternative hypothesis. Therefore, it can be concluded that there is a relationship between the level of awareness of the serious Accidents Punishment Act and the level of Safety Consciousness of Construction. One limitation of this study is that it relied on a subjective indicator through a survey, which may introduce variability in the difficulty level of the questionnaire items.

• Tunnel and Underground Space
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• v.18 no.6
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• pp.408-417
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• 2008

Rock mass classification methods such as RMR and Q system have different characteristics each other in parameters considered and applications, and so it is very important to prescribe the relationship between parameters for the analysis of correlativity of these methods. With the Held data of RMR and Q estimation in road construction sites, the acquaintance relations between RMR and Q of rock mass classifications are analyzed. The correlation equations between parameters of RMR and Q, matrix of correlation coefficients and the generalized form of acquaintance relation matrix are derived. This acquaintance relation matrix can be further extended to the form of generalized acquaintance relation network, and could be used to analyze the correlativity and to enhance the utility of common rock mass classification methods.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.525-533
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• 1998

Purpose: Radiation adaptive response in human peripheral lymphocytes and mouse bone marrow cells was investigated using both metaphase analysis and micronucleus assay. We assessed the correlation between both tests. Materials and Methods: Two groups of the human peripheral lymphocytes and mouse bone marrow cells were exposed to low dose (conditioning dose, 0,18 Gy) or high dose (challenging dose, 2 Gy) ${\gamma}$-rays. The other 4 groups were exposed to low dose followed by high dose after several time intervals (4, 7, 12, and 24 hours, respectively). The frequencies of chromosomal aberrations in metaphase analysis and micronuclei in micronucleus assay were counted. Results: Chromosomal aberrations and micronuclei of preexposed group were lower than those of the group only exposed to high dose radiation. Maximal reduction in frequencies of chromosomal aberrations were observed in the group to which challenging dose was given at 7 hour after a conditioning dose (p<0.001). Metaphase analysis and micronucleus assay revealed very good correlation in both human lymphocytes and mouse bone marrow cells (r=0.98, p<0.001 ; r=0.99, p=0.001, respectively). Conclusion: Radiation adaptive response could be induced by low dose irradiation in both human lymphocytes and mouse bone marrow cells. There was a significant correlation between metaphase analysis and micronucleus assay.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.1-8
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• 2011

This study is about the limits of GTEM cell using correlation factor between the OATS(Open area Test Site) and the GTEM cell. First, the field strengths at the 10 m distance OATS and in GTEM cell to obtain the experimental correlation factor are measured. Also, the EMI limits of radiated power are derived in GTEM cell as 3 position method is inversely transformed. The field strengths that calculated from theoretical models by 3 and 15 position methods are programmed and compared with measured data at the OATS. As the EMI limits of GTEM cell is newly defined, it will be use to substitute GTEM cell for OATS to efficiently measure EMI(Electromagnetic Interference).

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.85-98
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• 2017

In general, under the repetitive dynamic load generated by rail cars running on the track, subgrade soil experiences changes of stress conditions such as deviatoric stress (${\sigma}_d$) and bulk stress (${\theta}$). Due to the repetitive change of deviatoric stress (${\sigma}_d$) with number of loadings, the resilient modulus ($M_R$) can be obtained by using the measured resilient strain (${\varepsilon}_r$) after a sufficient number of loadings. At present, no plausible and unified test method has been proposed to obtain the resilient modulus of railway track subgrade soil. In this study, a possible test method for obtaining the resilient modulus ($M_R$) of railway track subgrade soil is proposed; this test, by utilizing repetitive triaxial compression testing, can consider all the important parameters, such as the confining stress, deviatoric stress, and number of loadings. By adapting and using the proposed test method to obtain $M_R$, $M_R$ values for compacted track subgrade soil can be successfully determined using soil obtained in three field sites of railway track construction with changing water content range from OMC. In addition, shear modulus (G) ~ shear strain (${\gamma}$) relation data were also obtained using a mid-size RC test. A correlation analysis was performed using the obtained G and $M_R$ values while considering the strain levels and modes of strain direction.

• Tunnel and Underground Space
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• v.13 no.2
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• pp.108-116
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• 2003

Measured convergence data of a tunnel were investigated by means of statistical and regression analysis, where the rock mass were mainly composed of andesite and granite. The rock mass around tunnel were classified by RMR method into five different ratings, and then convergence data which belong to individual ratings were statistically processed to find out the appropriate regression equations. Exponential equations were better coincided with measured data than logarithmic equations. As the number of rock mass rating was increased, the magnitude and standard deviation of convergence were increased. Final convergence data were also investigated to study the relevance with both maximum displacement rate and early measured convergence. Some brief results of their relevance are presented. For instance, the regression coefficient between final convergence and maximum displacement rate was turned out to be 0.87 for this studied tunnel.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.165-168
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• 2006

Fourier transform-near infrared spectroscopy (FT-NIRS) was evaluated for determination of total dietary fiber (TDF) content of brown rice. Enzymatic-gravimetric method was suitable to obtain reference values for calibration of NIR at 1,000-2,500 nm range. Standard error of laboratory procedure ranged 0.17 to 0.72%. Partial least square (PLS) regression was used to develop the calibration equations. Regression was performed automatically using NIRCal chemometric software. Accuracy of prediction model for TDF content was certified for regression coefficient (r), standard error of estimation (SEE) and standard error of prediction (SEP), showing 0.9780, 0.0636, and 0.0642, respectively. This prediction model can be used for determination of TDF in brown rice and would be useful for real-time analysis in food industry.

• Explosives and Blasting
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• v.36 no.4
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• pp.26-34
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• 2018

Explosions of vapor cloud formed due to the leakage from installations with flammable fuels have often occurred in Korea and foreign countries. In this study, TNT equivalency method and Multi-Energy method for vapor cloud explosion blast modelling are described and demonstrated in a case study. As TNT equivalency method is simple and direct, it has been widely used for modelling a vapor cloud explosion blast. But TNT equivalency method found to be difficult to select a proper correlation between the amount of combustion energy produced from the vapor cloud explosion and the equivalent amount of TNT to model its blast effects. Multi-Energy method assumes that the strength of vapor cloud explosion blast depends on the layout of the space where the vapor cloud is spreading. Strictly speaking, the explosive potential of a vapor cloud is dependent upon the density of the obstructed regions. In this study, Flixborough accident are analyzed as a case study to assess the applicability of TNT equivalency method and Multi-Energy method. TNT equivalency method and Multi-Energy method found to be applicable if coefficient of TNT equivalency and coefficient of strength of explosion blast are selected properly.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.5
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• pp.65-70
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• 2004

In this paper, we present a new methodology to analyze the characteristic of artery by using 4 channels photoplethysmograpy. The proposed parameter is a time difference of pulse transit time(PTT) between Pulse waves at finger site and at toe site. To verify the usefulness of the developed system volume pulse waves on 4 sites were measured simultaneously for total 51 normal subjects (male 26 and female 25) aged from 9 to 83 years old. And then correlations between the analysis parameters and age were evaluated by using linear regression analysis method. As the result of experiments, the change of parameter was found according to ages. The result of regression analysis about relationships between the parameter and ages for n=51, the coefficient of correlation of non-normalized data has 0.79770 in left side and 0.80599 in right side and the coefficient of correlation of normalized data by height has 0.81345 in left side and 0.81605 in right side.