• Geotechnical Engineering
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• v.13 no.1
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• pp.47-58
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• 1997

The predicted consolidation behavior of in-situ soft clay is quite different from the meas ureal one mainly due to the approximate numerical modelling techniques as well as the uncertainties involved in soil properties and geological configurations. In order to improve the prediction, this paper takes the following pinto consideration : an optimization technique should be adopted for characterizing the in-situ properties from measurements and also an equivalent and efficient model be considered to incorporate the actual 3-D effects. The soil parameters used be the modified Camflay model, which have an effect on the process of consolidation, were back-analyzed by BFGS scheme on the basis of settlements and pore pressures measured in real sites. The optimization technique was implemented in a general consolidation analysis program SPINED. By using the program, one may be able to appropriately analyze the timetependent consolidation behavior of soft deposits.

• Journal of the Korea Computer Graphics Society
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• v.29 no.3
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• pp.117-125
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• 2023

In the development of clothing design through virtual simulation, it is essential to minimize the differences between the virtual and the real world as much as possible. The most critical task to enhance the similarity between virtual and real garments is to find simulation parameters that can closely emulate the physical properties of the actual fabric in use. The simulation parameter optimization process requires manual tuning by experts, demanding high expertise and a significant amount of time. Especially, considerable time is consumed in repeatedly running simulations to check the results of applying the tuned simulation parameters. Recently, to tackle this issue, artificial neural network learning models have been proposed that swiftly estimate the results of drape test simulations, which are predominantly used for parameter tuning. In these earlier studies, relatively simple linear stiffness models were used, and instead of estimating the entirety of the drape mesh, they estimated only a portion of the mesh and interpolated the rest. However, there is still a scarcity of research on non-linear stiffness models, which are commonly used in actual garment design. In this paper, we propose a learning model for estimating the results of drape simulations for non-linear stiffness models. Our learning model estimates the full high-resolution mesh model of drape. To validate the performance of the proposed method, experiments were conducted using three different drape test methods, demonstrating high accuracy in estimation.

• Tunnel and Underground Space
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• v.22 no.4
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• pp.266-275
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• 2012

In this study, a method is devised to implement a supercritical $CO_2$ ($scCO_2$) injection environment on a laboratory scale and to investigate the effects of $scCO_2$ on the properties of rock specimens. Specimens of shale and sandstone normally constituting the cap rock and reservoir rock, respectively, were kept in a laboratory reactor chamber with $scCO_2$ for two weeks. From this stage, a chemical reaction between rock surface and the $scCO_2$ was induced. The effect of saline water was also investigated by comparing three conditions ($scCO_2$-rock, $scCO_2-H_2O$-rock and $scCO_2$-brine(1M)-rock). Finally, we checked the changes in the properties before and after the reaction by destructive and nondestructive testing procedures. The swelling of shale was a main concern in this case. The experimental results suggested that $scCO_2$ has a greater effect on the swelling of the shale than pure water and brine. It was also observed that the largest swelling displacement of shale occurred after a reaction with the $H_2O-scCO_2$ solution. The results of a series of the destructive and nondestructive tests indicate that although each of the property changes of the rock differed depending on the reaction conditions, the $H_2O-scCO_2$ solution had the greatest effect. In this study, shale was highly sensitive to the reaction conditions. These results provide fundamental information pertaining to the stability of $CO_2$ storage sites due to physical and chemical reactions between the rocks in these sites and $scCO_2$.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.167-177
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• 2002

A test method has been attempted to estimate the soil stiffness by measuring and analyzing dynamic signals of stress waves reflected at the bottom end of the SPT rod contacting a soil deposit. Before conducting a real size testing, a series of parametric studies were conducted in this paper to examine the applicability and the theoretical adequacy of the test method. As a result of these studies, it has been shown that the most significant influence factor affecting the amplitude ratio of the reflected wave to the incident wave at the rod-soil interface was the variation of soil stiffness. Also, the variation of the amplitude ratio was found to be closely related with the variation of impedance ratio of the soil deposit to the SPT rod. As a result, a potential of the test method could be proved to estimate the impedance and the elastic modulus of the soil deposit interfaced with the SPT rod using the test method.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.245-248
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• 2008

Concrete structures show time-dependent behavior due to creep and shrinkage of concrete and the uncertainties of creep and shrinkage are very huge. To reduce uncertainties of creep and shrinkage, it is substantially necessary to perform the long-term creep and shrinkage tests, but actual construction process doesn't allow it due to the limited time. Even though the tests are performed in laboratory, the values obtained from the tests could be different from the actual values in construction site because of the different environment between the laboratory and construction site and the model uncertainty itself. It is difficult to predict the long-term behaviors of concrete structures properly if the assumed creep coefficient obtained from Codes or the results of experiments is different from the real characteristics of concrete creep. In this study, for predicting the long-term behavior, the creep coefficients in reinforced concrete beams are estimated using creep sensitivity analysis from the measured deflections with time. And estimated creep coefficients using creep models of ACI Committee 209 and CEB-FIP MC90 are compared.

• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.79-90
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• 2004

Rutting on asphalt pavement surface is an important damage in most roadways in the world. Most of researches have developed prediction model for rutting on asphalt pavement as a function of physical properties of asphalt binder. But this study was devised to estimate rutting based on fundamental properties of asphalt mixture, not binder. Therefore this study objective is to estimate rutting based on volumetric properties, that is Air void, Void in mineral aggregate(VMA) and Void filled with asphalt(VFA), of asphalt mixture with various asphalt binders, aggregates and aggregate gradation. Results showed that it was possible to estimate rutting depth based on volumetric variables of asphalt mixture. In addition, VMA, the variable which is nor used In mix design in Korea, showed a significant correlation with rutting, It is recommended that VMA is adapted as a variable in domestic mix design. Also, It showed that VFA in the specification should be lowered at least 5% point since VFA was somewhat higher than optimum.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.451-461
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• 2016

The objective of this study is to illustrate the methods and procedures for estimating the failure probability of small fill dams subjected to earthquake events and to estimate the seismic failure probability of the Korean disaster risk fill dams where geotechnical information is not available. In this study, first of all, seismic failure probabilities of 7 disaster risk small fill dams, where geotechnical information is available, were evaluated using event tree analysis. Also, the methods and procedures for evaluating probabilities are illustrated. The relationship between dam height and freeboard for 84 disaster risk small dams, for which the safety diagnosis reports are available, was examined. This relationship was associated with the failure computation equation contained in the toolbox of US Army corps of engineers. From this association, the dam height-freeborard critical curve, which represents 'zero' failure probability, was derived. The seismic failure probability of the Korean disaster risk fill dams was estimated using the critical curve and the failure probabilities computed for 7 small dams.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.219-225
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• 1982

Four heat conduction models were examined for defatted soy-protein curds in order to get the 'intrinsic' thermal conductivity of soy-protein. As the result of examination, the 'intrinsic', thermal conductivities of soy-protein, frozen and unfrozen states, were determined on the basis of series model to be 0.488 W/m.K and 0.300 W/m.K, respectively. By using the 'intrinsic' thermal conductivity values of soybean protein and the series model, the effective thermal conductivity of soybean curds, with and without fat, at frozen and unfrozen states, was predicted satisfactorily, The temperature dependency of the effective thermal conductivity of soybean curd was mostly observed to correlate with the thermal conductivity of water and ice.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.9
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• pp.747-755
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• 2014

The heat transfer mechanism for radiation is directly related to the emission of photons and electromagnetic waves. Depending on the participation of the medium, the radiation can be classified into two forms: surface and gas radiation. In the present study, unknown radiation properties were estimated using an inverse boundary analysis of surface radiation in an axisymmetric cylindrical enclosure. For efficiency, a repulsive particle swarm optimization (RPSO) algorithm, which is a relatively recent heuristic search method, was used as inverse solver. By comparing the convergence rates and accuracies with the results of a genetic algorithm (GA), the performances of the proposed RPSO algorithm as an inverse solver was verified when applied to the inverse analysis of the surface radiation problem.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.581-588
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• 2014

The PSC bridges have recently been widely used in Korea. The PSC bridge is a structure whose performance is improved through the use of tendons and steel bars in deflection and cracking characteristics of the concrete. Therefore, measurement or estimation of the load acting on tendon is important in order to maintain the PSC bridges efficiently and safely. This paper deals with a numerical study on the deformation of a multi-tendon anchor head in order to verify the relationship between the load acting on tendon and the deformation of anchor head. All kinematics, material properties and contact nonlinearity are included for the precise analysis and numerical studies are performed by Abaqus. From the numerical results, it is verified that the hoop strain is most useful in the estimation of the load acting on tendon and strains are affected by various parameters such as friction coefficient, boundary conditions, and arrangement.