• Korean Journal of Child Studies
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• v.26 no.6
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• pp.217-236
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• 2005

The purpose of this study was to investigate whether preschoolers' peer interaction type and level differ depending on pair compositon and task type. Preschoolers' peer interaction type and level were compared among three kinds of pair compositions(with a Younger peer, with a same-age peer, and with an older peer) as well as between two types of tasks(tasks involving real objects, and tasks involving pictures). Subjects were seventy-eight four-year-old children recruited from six child-care centers in Seoul and Gyeonggi Province. The preschoolers were randomly assigned to one of the three kinds of pair compositions. Interaction processes of the pairs were recorded by a video camera, and the scenes were transcribed for content analyses. The traniscribed peer interactions were coded according to the categories that the researcher had generated. Statistical methods used for the data analysis were frequencies, percentiles, means, standard deviations, repeated measures ANOVA, paired t-tests, one-way ANOVA. Major findings of this study were as follows: There were significant differences preschoolers' in interaction type depending on the pair compositions and the types of tasks. The preschoolers paired with the older peer used abstract collaborative explanations more frequently than in two other types of pair composition. The preschoolers paired with the younger peer used explanations without collaboration and parallel behaviors more frequently than in two other types of pair composition.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.319-324
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• 2003

본 논문에서는 matched-pair design에서의 두 처리간 동등성/ 비열등성 검정에 대해 고려하였다. 기존에 비율차이나 risk ratio관점에서 동등성/비열등성 검정을 시행한 것과는 달리, 본 논문에서는 odds ratio에 기초하여 두 가지 검정통계량을 유도하였다. (1) constrained maximum likelihood estimator(mle)를 이용한 fieller type 통계량 (2) 제약없이 구한 mle를 사용한 wald-type 통계량). 비율 차이나 risk ratio에 기초한 기존의 통계적 방법들(비율차이에 근거한 (3) score-type 통계량과 (4) wald-type 통계량, risk ratio에 기초한 (5) fieller-type 통계량과 (6) wald-type 통계량)과 본 논문에서 제시한 두가지 통계량의 성능을 비교하기 위해 모의실험을 시행하였다. 모의실험 결과, 본 논문에서 제안한 constrained mle를 사용한 fieller type 통계량은 empirical type I error 측면에서 매우 만족스러운 결과를 보이고 있으며, 특히 비대각 셀의 확률이 작아질 경우에도 안정적인 성능을 보여준다.

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1225-1230
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• 2018

Schwinger pair production of electrons and positrons in a strong electric field is a prediction of nonperturbative quantum field theory, in which the out-vacuum is superposed of multi-particle states of the in-vacuum. Solving the Dirac or Klein-Gordon equation in the background field, though a linear wave equation, and finding the pair-production rate is a difficult or nontrivial job. The phase-integral method has recently been introduced to compute the pair production in space-dependent electric fields, and a complex analysis method has been employed to calculate the pair production in time-dependent electric fields. In this paper, we apply the complex analysis method to a Sauter-type electric field and other hyperbolic-type electric fields that vanish in the past and future and show that the Stokes phenomena in pair production occur when the time-dependent frequency for a given momentum has finite simple poles (polons) with pure imaginary residues.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.2
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• pp.137-140
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• 2009

In this paper, we introduce and formulate the definitions of Banach operator type k and Banach operator pair on intuitionistic fuzzy metric space. Thereafter we prove some properties and theorems on intuitionistic fuzzy metric space.

• East Asian mathematical journal
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• v.33 no.3
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• pp.271-289
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• 2017

It is our purpose in this paper to introduce the concept of best random proximity pair for subsets A and B of a separable Banach space E. We prove some best random approximation and best random proximity pair theorems of certain classes of random operators, which is the stochastic verse of the deterministic results of Eldred et al. [22], Eldred et al. [18] and Eldred and Veeramani [19]. Furthermore, our results generalize and extend recent results of Okeke and Abbas [42] and Okeke and Kim [43]. Moreover, we shall apply our results to study nonlinear stochastic integral equations of the Hammerstein type.

• Nonlinear Functional Analysis and Applications
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• v.27 no.3
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• pp.603-620
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• 2022

Several common fixed point theorems for a pair of weakly compatible mappings satisfying contractive inequalities of integral type in a metric space are proved. The results obtained in this paper improve or differ from a few results existing in the literature.

• Nonlinear Functional Analysis and Applications
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• v.29 no.1
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• pp.57-67
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• 2024

In this paper, we prove the existence of common fixed point for a pair of α-η-ψ-Geraghty contraction type maps in complete metric spaces using new type of α-admissible. These results extend and generalize some of the previously known results.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.111-121
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• 1997

The stability of a rotor-bearing system supported by swirl-controlled hybrid journal bearing with pair-type angled injection orifices is investigated for improvement of the whirl frequency ratio by allowing effective control of the tangential flow inside the bearing clearance, i.e., by achieving more freedom in controlling strength and direction of the supply tangential flow inside the bearing clearance. It is suggested that the system instability can be improved through the change of bearing dynamic characteristic parameters with the swirl control. The orifice diameter d$_0$ and recess injection angle $\alpha$ along with combinations of swirl/anti-swirl supply pressures and directions (3.0-3.0MPa, 4.0-2.0MPa, 2.0-4.0MPa) are selected for design parameters for swirl-controlled effective factors dependent on journal speeds (3000, 9000, 15000, 21000 rpm). It has been found that the orifice diameter do shows strong effects on effective maneuverability of direct-stiffness and direct damping values, while recess injection angle $\alpha$ results in substantial magnitude and direction of cross-stiffness. Specifically, recess injection parameters which are functions of angle of orifice feeding flow and recess dimensions showed very feasible effect on the stability of swirl-controlled rotor-bearing system.

• Tribology and Lubricants
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• v.13 no.3
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• pp.63-72
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• 1997

The stability of a rotor-bearing system supported by swirl-controlled hybrid journal bearing with pair-type angled injection orifices is investigated for improvement of the whirl frequency ratio by allowing effective control of the tangential flow inside the bearing clearance, i.e., by achieving more freedom in controlling strength and direction of the supply tangential flow inside the bearing clearance. It is suggested that the system instability can be improved through the change of bearing dynamic characteristic parameters with the swirl control. The orifice diameter $d_0$ and recess injection angle $\alpha$ along with combinations of swirl/anti-swirl supply pressures and directions (3.0~3.0 MPa, 4.0~2.0 MPa, 2.0~4.0 MPa) are selected for design parameters for swirl-controlled effective factors dependent on journal speeds (3000, 9000, 15000, 21000 rpm). It has been found that the orifice diameter $d_0$ shows strong effects on effective maneuverability of direct-stiffness and direct damping values, while recess injection angle $\alpha$ results in substantial effects on the magnitude and direction of cross-stiffness. Specifically, recess injection parameters which are functions of angle of orifice feeding flow and recess dimensions showed very feasible effect on the stability control of swirl-controlled rotor-bearing system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.33-43
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• 2003

The midwater pair trawl which is being used at present in Korea have several problems. Firstly, it is difficult to control the net height on high towing speed. Secondly, net breaking often occurs owing to floats and thirdly, the volume of net on the net drum is so large. This study is aiming for examining the possibility of application for the Korean midwater pair trawl through the model experiment of non-float midwater pair trawl. The model of non-float midwater pair trawl was manufactured as 1/100 of the full scale net which is being used in bottom pair trawl for 850ps class considering the Tauti's Similarity law. The model experiment was carried out to analyze the opening efficiency according to the variation of lower warp length and the opening efficiency was investigated between th proto type and non-float type. The results obtained can be summarized as follows ; 1. The hydrodynamic resistance of non-float type was about 10~20% smaller than that of the proto type and it increased about 1ton according to the increase of dL at the condition of the same flow speed. The resistance acting on the lower warp decreased about 5% but that of the upper warp increased according to the increase of lower warp length (dL) at the condition of the same flow speed. 2. The net height of the non-float type decreased almost linearly according as the increased of flow speed and it increased in a logarithmic functional form with the increase of the lower warp length at the condition of the same flow speed. On the decreasing rate of the net height, the non-float type was lower than the proto type and the difference of the decreasing rate was about 12% at 3.0 knot, 25% at 4.0 knot, 25% at 4.0 knot respectively when dL was 30m. 3. The net width of non-float type was not varied so much as only 2m range and was larger than that of proto type. 4. The mouth area of non-float type decreased in a exponential functional form. On the decreasing rate of the mouth area, the non-float type was lower than the proto type. The filtering volume increased in a logarithmic functional form with increasing flow speed and the filtering volume of proto type decreased steeply over 3.0knot, but that of non-float type increased until 4.0knot. 5. The optimal length of lower warp was when the value of dL was about 30m and the optimal position of front weight was at the connection point of four net pendants.