• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.145-153
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• 2003

The resonant column testing determines the shear modulus and material damping factor dependent on the shear strain magnitude, based on the wave-propagation theory. The determination of the dynamic soil properties requires the theoretical formulation of the dynamic behavior of the resonant column testing system. One of the theoretical formulations is the use of the wave equation for the soil specimen in the resonant column testing device. Wood, Richart and Hall derived the wave equation by assuming the linear elastic soil, and didn't take the material damping into consideration. Hardin incorporated the viscoelastic damping of soil in the wave equation, but he had to assume the material damping factor for the determination of the shear modulus. For the better theoretical formulation of the resonant column testing, this study derived a new wave equation to include the viscosity of soil, and proposed an approach for the solution. Also, in this study, the equation of motion for the testing system, which is another approach of the theoretical formulation of the resonant column testing, was also derived. The equation of motion leads to the better understanding of the resonant column testing, which includes the dynamic magnification factor and the phase angle of the response. For the verification of the proposed equation of motion for the resonant column testing, the finite element analysis was performed for the resonant column testing. The comparison of the dynamic magnification factors and the phase angles far the system response were performed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.43-54
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• 1992

For shallow arches with large dynamic loading, linear analysis is no longer considered as practical and accurate. In this study, a method is presented for the dynamic analysis of shallow arches in which geometric nonlinearity must be considered. A program is developed for the analysis of the nonlinear dynamic behavior and for evaluation of critical buckling loads of shallow arches. Geometric nonlinearity is modeled using Lagrangian description of the motion. The finite element analysis procedure is used to solve the dynamic equation of motion and Newmark method is adopted in the approximation of time integration. A shallow arch subject to radial step loads is analyzed. The results are compared with those from other researches to verify the developed program. The behavior of arches is analyzed using the non-dimensional time, load, and shape parameters. It is shown that geometric nonlinearity should be considered in the analysis of shallow arches and probability of buckling failure is getting higher as arches are getting shallower. It is confirmed that arches with the same shape parameter have the same deflection ratio at the same time parameter when arches are loaded with the same parametric load. In addition, it is proved that buckling of arches with the same shape parameter occurs at the same load parameter. Circular arches, which are under a single or uniform normal load, are analyzed for comparison. A parabolic arch with radial step load is also analyzed. It is verified that the developed program is applicable for those problems.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.478-482
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• 2006

The domestic enterprises in order to secure the freshness location of market from the international competition which is keen are propelling a price and a quality high position strategy steadily. It is put in competitive situation with the overseas enterprises and even from construction industry it follows in construction market opening and there is not another idea to the research the management strategies, directions and focus competitive elements of the enterprise against, what it sees consequently and to rise to the priority where the competitive power reinforcement of the enterprise is important, it becomes. Competitive power of like this enterprise for a reinforcement the technique which induces a big interest 6 Sigma is technique from the many companies. 6 sigma preceding researches of manufacturing and service industry the fact that it is accomplished with the object which will carry most. The research which relates with construction industry is staying to an introduction of 6 sigma the investigation phase, the actual introduction introduces and "S" construction there is not only a possibility against the application result of having a limit because it is applying. It is like that but like referring to a minute description for the international competitive power security which it follows in the change which market environment is sudden 6 sigma the introduction will judge, indispensability development of the logical propriety against hereupon and it will reach and it verifies the question investigation for to lead, 6 sigma of the construction companies it confirms the application possibility and presents the propulsion model as 6 sigma the fact that overcoming the limit characteristic of that introduction application as objective of sample research means it will do.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6698-6707
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• 2015

The purpose of this study is to investigate relationships among career identity, satisfaction in major, and adjustment to college life for students who major in food and nutrition that is complex and has diversity of carrier and to serve as a guideline for career counselling and college life. After reliability and validity of the data collected were verified using IBM SPSS Statistics 22, difference in variables according to characteristics of students was examined using independent t-test, ANOVA, and chi-square test. The results showed that there was a positive correlation among career identity, satisfaction in major, and adjustment to college life and students who had prior knowledge of their major showed a higher level of career identity, satisfaction in major and adjustment to college life compared to those who did not. Therefore, it is suggested that guidance on Department of Food and Nutrition should be provided to students before they decide on their major for their increased satisfaction in major, smooth adjustment to college life, and career decision. With this data, we recognize the gravity of psychological factor and carrer consciousness may provide base data to practical use of student life and carrer guidance.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.4
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• pp.25-33
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• 2015

The study of ecosystem assessment(ES) is based on land cover information, and primarily it is performed at the global scale. However, these results as data for decision making have a limitation at the aspects of range and scale to solve the regional issue. Although the Ministry of Environment provides available land cover data at the regional scale, it is also restricted in use due to the intrinsic limitation of on screen digitizing method and temporal and spatial difference. This study of objective is to generate UAV land cover map. In order to classify the imagery, we have performed resampling at 5m resolution using UAV imagery. The results of object-based image segmentation showed that scale 20 and merge 34 were the optimum weight values for UAV imagery. In the case of RapidEye imagery;we found that the weight values;scale 30 and merge 30 were the most appropriate at the level of land cover classes for sub-category. We generated land cover imagery using example-based classification method and analyzed the accuracy using stratified random sampling. The results show that the overall accuracies of RapidEye and UAV classification imagery are each 90% and 91%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2D
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• pp.137-145
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• 2012

According to the National Police Agency, the total number of traffic accidents which occurred in 2010 was 226,878. Intersection accidents accounts for 44.8%, the largest portion of the entire traffic accidents. An research on the signalized intersection is constantly made, while an research on the unsignalized intersection is yet insufficient. This study selected traffic volume, road width, and sight distance as the input variables which affect unsignalized intersection accidents, and number of accidents as the output variable to build a model using ANFIS(Adaptive Neuro-Fuzzy Inference System). The forecast performance of this model is evaluated by comparing the actual measurement value with the forecasted value. The compatibility is evaluated by R2, the coefficient of determination, along with Mean Absolute Error (MAE) and Mean Square Error (MSE), the indicators which represent the degree of error and distribution. The result shows that the $R^2$ is 0.9817, while MAE and MSE are 0.4773 and 0.3037 respectively, which means that the explanatory power of the model is quite decent. This study is expected to provide the basic data for establishment of safety measure for unsignalized intersection and the improvement of traffic accidents.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.919-930
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• 2014

In this study, the load capacities and behaviors of a shotcrete member with steel supports, as composite member, are investigated numerically by using a fiber section element. The cross section of a shotcrete lining with steel support is divided into a bundle of fibers, which are allocated nonlinear stress-strain relations and used for determining internal forces. To verify the used approach of the finite element method for shotcrete with steel supports, the load-displacement relations of shotcrete lining obtained by numerical analysis are compared with existing experimental results and are analyzed with the stress distribution of the shotcrete and steel support obtained numerically. As a result, it is shown that the proposed approach can predict the load capacities of each material and the overall nonlinear behavior of shotcrete lining with steel supports. The change of location of the neutral axis and the flexural resistance ratio of each material are also derived from the stress distribution of the cross section of the shotcrete lining with steel supports. From the results, it is concluded that the flexural resistance performance of steel support should be considered in shotcrete lining design.

• Journal of the Korean School Mathematics Society
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• v.16 no.4
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• pp.771-796
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• 2013

The purpose of the study is to analyze the phenomenon of private education and to get the countermeasures of it. To do this, we approached the phenomenon of private education from the game theory, which is famous in economics. As result, we could make the mathematical model. One is a model consisted of two-person. This is a mathematical model simplifying the competition within the school. The problem of private education can be solved by the disconnection with private education and exam of school in this model. The other is a model consisted of three-person. This is a mathematical model simplifying the interscholastic competition. The problem of private education can not only be solved by the disconnection with private education and exam of school, but can be also solved by the specificity of school education in this model. We will hope that our study can give an aid in deciding an educational policy.

• Tunnel and Underground Space
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• v.30 no.4
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• pp.306-319
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• 2020

Characterizations of Excavation Damage Zone (EDZ), which is hydro-mechanical degrading the host rock, are the important issues on the geological repository for the spent nuclear fuel. In the DECOVALEX 2019 project, Task G aimed to model the fractured rock numerically, describe the hydro-mechanical behavior of EDZ, and predict the change of the hydraulic factor during the lifetime of the geological repository. Task G prepared two-dimensional fractured rock model to compare the characteristics of each simulation tools in Work Package 1, validated the extended three-dimensional model using the TAS04 in-situ interference tests from Äspö Hard Rock Laboratory in Work Package 2, and applied the thermal and glacial loads to monitor the long-term hydro-mechanical response on the fractured rock in Work Package 3. Each modelling team adopted both Finite Element Method (FEM) and Discrete Element Method (DEM) to simulate the hydro-mechanical behavior of the fracture rock, and added the various approaches to describe the EDZ and fracture geometry which are appropriate to each simulation method. Therefore, this research can introduce a variety of numerical approaches and considerations to model the geological repository for the spent nuclear fuel in the crystalline fractured rock.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.65-77
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• 2008

LOS(Level of Service) concept are popularly used in many countries as the MOEs to evaluate the road construction and operation plans. However, MOEs such as travel time and delay only measure quantitative factors describing traffic flow, although qualitative factors such as scenic, comfort and reliable factors are very important for roadway drivers to define the LOS. Therefore, this paper are focusing on verifying the difference between perceived LOS and LOS in KHCM, and proving qualitative factors affecting Drivers' Perceived LOS in Urban Arterial. As a result, following outputs are obtained; (1) verifying the difference between perceived LOS(PLOS) and LOS in KHCM (2) proving that qualitative factors such as scenic and driver behavior factors affects PLOS (3) suggesting that qualitative factors should be considered in MOEs of LOS