• The Korean Journal of Applied Statistics
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• v.25 no.4
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• pp.543-552
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• 2012

Parrondo paradox is a counter-intuitive phenomenon where two losing games can be combined to win or two winning games can be combined to lose. When we trade stocks with a history-dependent Parrondo game rule (where we buy and sell stocks based on recent investment outcomes) we found Parrondo paradox in stock trading. Using stock data of the KRX from 2008 to 2010, we analyzed the Parrondo paradoxical cases in the Korean stock market.

• Journal of Mechanical Science and Technology
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• v.19 no.11
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• pp.2077-2081
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• 2005

A symmetry breaking nonlinear fluid flow in a two-dimensional wall-driven square cavity taking symmetric boundary condition after some transients has been investigated numerically. It has been shown that the symmetry breaking critical Reynolds number is dependent on the time history of the boundary condition. The cavity has at least three stable steady state solutions for Re=300-375, and two stable solutions if Re>400. Also, it has also been showed that a particular solution among several possible solutions can be obtained by a controlled boundary condition.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.35-40
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• 2000

The influence of cyclic loading history on the creep behavior of the 30 vol% hot-pressed $SiC_f/Si_3N_4copmposite was experimentally investigated at $1200^{\circ}C$. The duration of loading/unloading had great effects on the creep behaviors. The short term duration cyclic loading history test results showed significant reduction in the primary and steady-state creep rates. For example, 300sec loading/300sec unloading history resulted in 70% lower steady-state creep rate than that of the continuous loading. However the long term duration cyclic loading history test results showed little change in creep rates compared to those of the continuous one. The reason for the significant change in the short term duration cycles was estimated due to the change in the stress redistribution between the fiber and matrix during the creep recovery in the primary stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.423-424
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• 2007

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.313-316
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• 2005

In the present study, Bauschinger effect was investigated for the micro-alloying forging steel which has been developed for about 30 years ago to save energy consumption by eliminating the heat treatment processes in the forging industry. The micro-alloying steels used fur cold forging industry mainly aim to replace the usual carbon steel. With the conventional carbon steels, all the deformation history can be eliminated after the final heat treatment(quenching and tempering). In the case of micro-alloying forging steels, however, the prior deformation history should be taken into consideration to meet the mechanical property requirement since the microstructure of micro-alloying steels might exhibit the Bauschinger effect, which was not needed to consider in the case of conventional carbon steel having quenching and tempering treatment. In the present study, the reverse loading tests were carried out to determine the Bauschinger effect of micro-alloying steel which composed of ferrite and cementite phases.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.474-478
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• 2004

Based on the recent laboratory experiments (Kim et al. 2004), comparisons of caisson sliding distance are made between the computations and experiments. The time history model of wave force, which is proposed by Tanimoto et al. (1996), is modified in the standing wave part of horizontal and uplift wave forces because of the overestimation of the time history model. The comparison between experimental and computational sliding distance has showed that the caisson tilting increases the resistant force to the horizontal sliding. Therefore, a titling resistant force, which is caused by caisson tilting, is introduced into computation of sliding distance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.11-12
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• 2011

This study examine Effect of Change of Compressive Strength of Concrete Members with Insulating Gang form on Temperature History of Concrete Positions. Test show, insulating gang forms differences and gang forms have 10℃ on peak point temperature of surface and Center if temperature history have 24Mpa by change of compressive strength. In addition, there have 14℃(16℃) on peak point temperature of surface and Center if temperature history have 40(60)Mpa. Therefore, insulating gang forms have an effect insulating performance.

• Computers and Concrete
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• v.11 no.5
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• pp.463-473
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• 2013

As known, concrete classes are described as strength of standard specimens produced and kept in ideal conditions, not including reinforcement and not subjected to any load effect before. Under the circumstances, transforming core strengths to the standard specimen strength is necessary and considering all parameters, affected on the core strength, is inevitable. In fact, effects of the reinforcement and the load history on concrete strength are generally neglected when these mentioned transforms are performing. The main purpose of this paper is investigating the effects of the reinforcement and the load history on the core strength. This investigation is experimentally performed on cores drilled from specimens having different keeping conditions, reinforced, unreinforced, subjected to bending and central pressure in various proportions of failure load during specified periods. Obtained results show that the importance of these effects cannot be neglected.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.7-16
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• 2010

Stress history increases the residual horizontal stress of granular soil and, consequently, the penetration resistance. This study analyzes the effect of stress history on the cone resistance ($q_c$), horizontal stress index ($K_D$) and dilatometer modulus ($E_D$) of CPT and DMT from calibration chamber specimen in OC as well as NC state. Test results show that the normalized cone resistance by mean effective stress correlates well with the relative density and the state parameter, whereas the normalized cone resistance by vertical effective stress is a little affected by stress history. The influence of stress history is more reflected on $K_D$ than $E_D$ and $q_c$. The $K_D/K_0$, in which the effect of stress history on $K_D$ is compensated by the at-rest coefficient of earth pressure, $K_0$, is related to relative density, state parameter and the normalized cone resistance by mean effective stress. It is also observed that the normalized dilatometer modulus by mean effective stress ($E_D/{\sigma}_m'$) shows a unique correlation with the state parameter, regardless of stress history.

• Journal of Korean language education
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• v.29 no.3
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• pp.117-144
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• 2018

The purpose of this study is to explore the linguistic elements that can promote academic literacy in terms of content-based instructions for KSL learners. In order to study the characteristics of learning languages for subjects, focus was given to the framework of systematic functional linguistics that has been extensively used in ELL teaching and learning research in the United States and Australia. History, which is taught in all classes and classified as a required course, was the subject of analysis. From the history curriculum, the elementary school level texts "Social Studies 5-2" and "Social Studies 6-1" were chosen for the analysis. Based on the results, we can come to the following conclusions. First, history textbooks are divided into narrative and analytical explanatory sub-genres based on their content, and there are differences in the factors that need to be focused on to find the main information. Second, the vocabulary of history textbooks should focus on the use of verbs which comprehend material processes. Particularly, learners should pay attention to the differences in meaning between low-frequency expressions. We hope that the results of this study will have a positive effect on history subject learning for learners in the "Adaptive Korean Course" and will help establish direction in terms of building curriculum contents for KSL learners.