• International Journal of CAD/CAM
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• v.12 no.1
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• pp.9-19
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• 2012

Generation of optimum planar B-spline curve in terms of minimum deviation and required fairness to approximate a target shape defined by a strip-shaped unorganized 2D point cloud is studied. It is proposed to use the location of control points as variables within the geometric optimization framework of point distance minimization. An adaptive simulated annealing heuristic optimization algorithm is developed to iteratively update an initial approximate curve towards the target shape. The new implementation comprises an adaptive cooling procedure in which the temperature change is adaptively dependent on the objective function evolution. It is shown that the proposed method results in an improved convergence speed when compared to the standard simulated annealing method. A couple of examples are included to show the applicability of the proposed method in the surface model reconstruction directly from point cloud data.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.1
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• pp.1-5
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• 2018

This work demonstrated the application of an artificial neural network model for predicting the Jominy hardness curve by considering 13 alloying elements in low alloy steels. End-quench Jominy tests were carried out according to ASTM A255 standard method for 1197 samples. The hardness values of Jominy sample were measured at different points from the quenched end. The developed artificial neural network model predicted the Jominy curve with high accuracy ($R^2=0.9969$ for training and $R^2=0.9956$ for verification). In addition, the model was used to investigate the average sensitivity of input variables to hardness change.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.101-104
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• 2006

In the past study, the fragility curve for the evaluation of earthquake resistance and earthquake-related damage of concrete bearing wall structures were studied. The fragility curve represents the probability of being in or exceeding a given damage state such as Slight, Moderate, Extensive or Complete structural damage state, and is defined as a cumulative lognormal distribution. Each fragility curve is characterized by median and lognormal standard deviation values. We performed parametric pushover analysis for typical 12 and 24 stories apartment buildings. Based on the results, the fragility curves of concrete wall structures were standardized. Using the fragility curve, engineers can directly evaluate the probability of a damage state to a spectral displacement of interest.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.54.1-54.1
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• 2019

We use iterative smoothing reconstruction method along with exploring in the parameter space of the light curves of the JLA supernova compilation (Joint Light-curve Analysis) to simultaneously reconstruct the expansion history of the universe as well as putting constrains on the light curve parameters without assuming any cosmological model. Our constraints on the light curve parameters of the JLA from our model-independent analysis seems to be closely in agreement with results assuming ΛCDM cosmology or using Chevallier-Polarski-Linder (CPL) parametrization for the equation of state of dark energy. This implies that there is no hidden significant feature in the data that could be neglected by cosmology model assumption. The reconstructed expansion history of the universe and properties of dark energy seems to be in good agreement with expectations of the standard ΛCDM model. Our results also indicate that the data allows a considerable flexibility for expansion history of the universe.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.475-481
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• 2011

The TMDL standard flow as applying watershed management regime uses the average low flow of past 10 years. Moreover, the TMDL implementation assessment has been enforced through management of pollutant load satisfied objective water quality. Even though the present allocation and management through averaged low flow are still convenient, they are not enough to solve ultimate goals of watershed management to keep up recovery of water body. To maintain the same water quality concentration, the standard flow is required to consider total discharge in management plan which helps to keep healthy ecosystem. In view of this, it would be possible to approach reasonable assessment by reflecting variably changeable discharge from precipitation-streamflow relation and the TMDL standard establishment considering artificial regulated flow. Therefore, this study attempts to develop the TMDL method using Load Duration Curve (LDC) and Streamflow-Load Rating Curve (QLRC) considering total discharge and finds drawbacks with solutions as applying on Nakdong river TMDL unit watershed. Finally, this research evaluates possibility of application on pollutant load allocating and implementation assessment in Korea.

• Journal of Conservation Science
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• v.37 no.5
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• pp.451-463
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• 2021

In this study we conducted component analyses of portable XRF detectors using four Au-Cu alloy standard samples to improve their accuracy by drawing up a calibration curve based on ICP-OES standard values. The portable XRF analysis found absolute errors of 0.3 to 3.7 wt% for Au and 0.2 to 8.2 wt% for Cu, confirming that the error range and standard deviation differed from one detector to another. Furthermore, the calibration curve improved their accuracy, such that the relative error rates of Au and Cu decreased from 9.8% and 14% to 3.5% and 3.7%, respectively. Accordingly, an experiment to confirm the calibration curve was conducted using unknown samples, finding that the measured values of the unknown samples fell on the calibration curve. Therefore, to accurately analyze the components of metal cultural heritage items, it is necessary to prepare a calibration curve for each element after checking whether the detector is suitable for the artifact.

• Journal of Veterinary Clinics
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• v.33 no.2
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• pp.97-101
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• 2016

In the field of clinical medicine, diagnostic accuracy studies refer to the degree of agreement between the index test and the reference standard for the discriminatory ability to identify a target disorder of interest in a patient. The receiver operating characteristic (ROC) curve offers a graphical display the trade-off between sensitivity and specificity at each cutoff for a diagnostic test and is useful in assigning the best cutoff for clinical use. In this end, the ROC curve analysis is a useful tool for estimating and comparing the accuracy of competing diagnostic tests. This paper reviews briefly the measures of diagnostic accuracy such as sensitivity, specificity, and area under the ROC curve (AUC) that is a summary measure for diagnostic accuracy across the spectrum of test results. In addition, the methods of creating an ROC curve in single diagnostic test with five-category discrete scale for disease classification from healthy individuals, meaningful interpretation of the AUC, and the applications of ROC methodology in clinical medicine to determine the optimal cutoff values have been discussed using a hypothetical example as an illustration.

• Computers and Concrete
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• v.16 no.1
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• pp.179-190
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• 2015

An experimental program has been carried out to investigate the effect of edge-slope on compressive strength of concrete specimens. In this study, effect of such slope was investigated by testing 100 standard cylinder specimens and 40 standard cubes. When molds are put on a slanted place, wet concrete starts to flow through the open end of mold. It keeps flowing until it reaches to a parallel surface with the place over which it was placed. That creates a sloped surface over the loading area. Experimental results revealed significant relationships between failure loads and slope of loading surface for cylinders. Angled cracks occurred in sloped cylinder specimens. Tension cracks occurred in cube specimens. Fracture mechanisms were also evaluated by using finite element analyses approach. Experiments yielded an exponential curve with bandwidth for cylinders. Average value of curve is $y={\frac{\pi}{2}}e^{-cf}$ between slope and compressive strength. Inclination is much effective parameter for cylinders than cubes.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.1
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• pp.39-44
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• 2015

The fracture toughness of 2.25Cr-1Mo cast steel (SA217-WC9) samples which were taken from the check valves of feed water piping of Korean Standard Nuclear Power Plant(KSNPP) was measured by Master Curve method. The measured $T_0$ reference temperature of SA217-WC9 steel was $-30^{\circ}C$. The obtained $T_0$ was compared to the derived value from Charpy impact test data following to SINTEP procedure. The heat-to-heat variation in fracture toughness of SA217-WC9 steel was observed. It was found that the low toughness of a heat of SA217-WC9 steel was attributed to the coarse MnS inclusion originated by high sulfur content as the results of microanalyses.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.91-98
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• 2015

This paper has proposed a reinforcing method for damaged RC columns with SRF sheets and Aramid rods. In order to verify the effectiveness and performance, two original columns and two reinforced columns with SRF sheets and Aramid rods were developed and tested under lateral cyclic displacement and a constant axial load. The test showed that the improvement of energy dissipation capacity was increased in terms of strength and ductility. In addition, an analytical modeling of the standard specimens was proposed using Response-2000 and ZeusNL program. The results of analytical and experimental studies for two standard columns were compared in terms of loading-displacement curve and energy dissipation capacity based on the nonlinear static analysis.