• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.239-239
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• 2015

This study presents a bivariate extension of the goodness-of-fit measure for regional frequency distributions developed by Hosking and Wallis [1993] for use with the method of L-moments. Utilising the approximate joint normal distribution of the regional L-skewness and L-kurtosis, a graphical representation of the confidence region on the L-moment diagram can be constructed as an ellipsoid. Candidate distributions can then be accepted where the corresponding the oretical relationship between the L-skewness and L-kurtosis intersects the confidence region, and the chosen distribution would be the one that minimises the Mahalanobis distance measure. Based on a set of Monte Carlo simulations it is demonstrated that the new bivariate measure generally selects the true population distribution more frequently than the original method. An R-code implementation of the method is available for download free-of-charge from the GitHub code depository and will be demonstrated on a case study of annual maximum series of peak flow data from a homogeneous region in Italy.

• Communications for Statistical Applications and Methods
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• v.26 no.3
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• pp.239-259
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• 2019

The transmuted generalized extreme value (TGEV) distribution was first introduced by Aryal and Tsokos (Nonlinear Analysis: Theory, Methods & Applications, 71, 401-407, 2009) and applied by Nascimento et al. (Hacettepe Journal of Mathematics and Statistics, 45, 1847-1864, 2016). However, they did not give explicit expressions for all the moments, tail behaviour, quantiles, survival and risk functions and order statistics. The TGEV distribution is a more flexible model than the simple GEV distribution to model extreme or rare events because the right tail of the TGEV is heavier than the GEV. In addition the TGEV distribution can adjusted various forms of asymmetry. In this article, explicit expressions for these measures of the TGEV are obtained. The tail behavior and the survival and risk functions were determined for positive gamma, the moments for nonzero gamma and the moment generating function for zero gamma. The performance of the maximum likelihood estimators (MLEs) of the TGEV parameters were tested through a series of Monte Carlo simulation experiments. In addition, the model was used to fit three real data sets related to financial returns.

• Steel and Composite Structures
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• v.32 no.1
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• pp.37-57
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• 2019

This paper presents experimental and analytical studies to evaluate the cyclic behaviour of Circular Reinforced Concrete column Steel beam (CRCS) connections. Two 3/4-scale CRCS specimens are tested under quasi-static reversed cyclic loading. Specimens were strengthened with a tube plate (TP) and a steel doubler plate (SDP). Furthermore; nine interior beam-through type RCS connections are simulated using nonlinear three-dimensional finite element method using ABAQUS software and are verified with experimental results. The results revealed that using the TP improves the performance of the panel zone by providing better confinement to the concrete. Utilizing the TP at the panel zone may absorb and distribute stress in this region. Results demonstrate that TP can be used instead of SDP. Test records indicate that specimens with TP, with and without SDP maintained their maximum strength up to 4% drift angle, satisfying the recommendation given by AISC341-2016 for composite special moment-resisting frames.

• International Journal of High-Rise Buildings
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• v.9 no.4
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• pp.325-334
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• 2020

This paper aims to evaluate the interfacial stress concentrations on connection between vertical through-plate and H-beam in CFT column. Full-scale experiments were performed on three specimens with varying thickness of the vertical through-plate to investigate the interfacial stress concentration factor in the connections. The specimens underwent brittle failure at the location where the steel beam is connected to the vertical through-plate before the steel beam reached its plastic moment. The strain data of the part were analyzed, and the sectional analyses were conducted to determine appropriate residual stress models. In addition, the stress concentration factor was quantified by comparing the analytical local behavior in which the stress concentration is not reflected and the experimental data reflecting the stress concentration. The results showed that the maximum reduction of the stress concentration factor due to an increase in the thickness of the vertical through-plate is 50.3%.

• Wind and Structures
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• v.32 no.4
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• pp.341-354
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• 2021

Articulated towers are one of the class of compliant offshore structures that freely oscillates with wind and waves, as they are designed to have low natural frequency than ocean waves. The present study deals with the dynamic response of a double-pendulum articulated tower under hydrodynamic and aerodynamic loads. The wind field is simulated by two approaches, namely, single-point and multiple-point. Nonlinearities such as instantaneous tower orientation, variable added mass, fluctuating buoyancy, and geometrical nonlinearities are duly considered in the analysis. Hamilton's principle is used to derive the nonlinear equations of motion (EOM). The EOM is solved in the time domain by using the Wilson-θ method. The maximum, minimum, mean, and standard deviation and salient power spectral density functions (PSDF) of deck displacement, bending moment, and central hinge shear are drawn for high and moderate sea states. The outcome of the analyses shows that tower response under multiple-point wind-field simulation results in lower responses when compared to that of single-point simulation.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.85-93
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• 2014

The purpose of this study was to investigate a relationship among Taekwondo, soccer and gymnastic athletes their balance ability and lower extremity muscle strength, muscle endurance and also whether these variables show differences by sports type. For this purpose, 10 Taekwondo athletes, 10 soccer athletes and 10 gymnastic athletes that is a high school in I area were selected and their balance ability, isokinetic muscle strength and muscle endurance were measured by using force platform (AMTI) and isokinetic measurement (HUMAC NORM). Then the following results were obtained by conducting pearson product-moment correlation analysis and one-way ANOVA. In case of both right and left foot one-leg standing with open-eyes, there was a relation between both knee extension maximal muscle strength of Taekwondo, soccer, gymnastic athletes and balance ability, and in case of right foot one-leg standing with open-eyes, there was a relation between that is right plantar flexion and dorsi flexion maximum muscle strength and muscle endurance of Taekwondo, soccer, gymnastic athletes and their balance ability. Furthermore, in case of left dorsi flexion maximum muscle strength, there were significant differences in order of Taekwondo, gymnastics and soccer, and for isokinetic plantar flexion maximum muscle endurance, both right and left showed significant differences in order of Taekwondo, gymnastic and soccer.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.691-697
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• 2011

In this study, the vessel collision protective structure and the vessel were modeled numerically and the quasi-static collision analysis was performed to evaluate the maximum protection capacity. In the modeling process of protective structure, the nonlinear behaviors of structure and the supporting conditions of ground including pull-out action were considered. In that of collision vessel, the bow of vessel was modeled precisely, because of the nonlinear behaviors were concentrated on it. For the efficient analysis, the mass scaling scheme was applied, also. To evaluate the differences and efficiency, the dynamic analyses were performed for the same model, additionally. Based on the obtained energy dissipation curves of the structure and the vessel, the moment that the collision force affected to the bridge substructures was determined and the maximum allowable collision velocity was evaluated. Because of the energy dissipation bound can be recognized clearly, this scheme can be used efficient in engineering work.

• Journal of KIISE
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• v.44 no.3
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• pp.314-322
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• 2017

In MMORPG (Massively Multiplayer Online Role-Playing Game), users advance their own characters to get to the maximum (max) level by performing given tasks in the game scenario. Although it is crucial to retain users with high levels for running online games successfully, little efforts have been paid to investigate them. In this study, by analyzing approximately 60 million in-game logs of over 50,000 users, we aimed to investigate the process through which users achieve the max level and churn of such users since the moment of achieving the max level, and determine possible indicators related to churn after the max level. Based on the result, we can predict churn of the max level users by employing behavioral patterns before the max level. Moreover, we found users who are socially active and communicate with many people before the max level are less likely to leave the service (p<0.05). This study supports that communication patterns are important factors for persistent usage of the users who achieve the max level, which has practical implications to guide elite users on enjoying online games in the long run.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.635-644
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• 2012

In order to design a wave energy generating system, a 6-DOF analysis technique is applied to the three-Dimensional CFD analysis on of a floating body and the behavior is interpreted according to the nature of the incoming wave. A wave period of 5.5s & amplitude of 0.57m from Marado is chosen. 12 case of natural pitching period from 1.25 to 2.8s has been modeled. The relation between tuning factor & pitch angle for the waves generated is compared to analyze the effects of energy absorption variables, namely mass moment of inertia, angular velocity and angular acceleration. From the results obtained, we conclude that model L is the maximum power absorbed, 6kW approximately. A maximum pitch angle of 1.91 degree was attained by Model F, and the maximum displacement of nearly 0.7m was attained by Model L among models D, F and L.

• Fire Science and Engineering
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• v.29 no.4
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• pp.73-80
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• 2015

In this study, the conditions of explosion range of gasoline, which is used as combustion improver, are experimentally analyzed. Two types of compartment, which is the small scale ($0.5m{\times}0.5m{\times}1.0m$) and the middle scale ($0.5m{\times}0.5m{\times}1.0m$), are mocked-up and the auto-control systems are installed in order to measure the vaporized gasoline and the moment of pressure, ignition time and maximum pressure. In case the maximum flammable limit of gasoline is up to 22.4 Vol% not the generalized range of 1.4~7.6 Vol% when nichrome igniter of $700^{\circ}C$ is used. These results can be appled to the analytical prediction of fire identification in the field of explosion.