• 대한산업공학회지
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• 제43권3호
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• pp.176-183
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• 2017

In recent years, studies about multitasking becomes more important. During multitasking, operators can feel frustration when they are interrupted during the task and frustration can affect operator's emotional state and performance. However there is no research on measuring the frustration quantitatively in multitasking environment. In this paper, we suggested quantitative measurement of frustration during multitasking. In order to measure the frustration, we made a mathematical representation with emotional decay model and the initial intensity of frustration based on cognitive closure theory. The amount of initial intensity could be represented as the ratio of actual remaining time to expected remaining time. By the experiment, we measured the frustration during the experiment and compared this values with values of frustration dimension of NASA-TLX. Finally we got the linear regression model with a good accuracy ($R^2=0.986$). This study contributes to measuring the emotion quantitatively by the relation of expected and actual remaining time in multitasking environment.

• 설비공학논문집
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• 제19권12호
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• pp.831-841
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• 2007

This work is to extend the elliptic operator, which has been already adopted in turbulent stress model, to fully developed turbulent buoyant channel flows with changing the orientation of the buoyancy vector to be perpendicular to the channel walls. The turbulent heat flux models based on the elliptic concept are employed and closely linked to the elliptic blending second moment closure which is used for the prediction of Reynolds stresses. In order to reflect the stable or unstable stratification conditions, the present model introduces the gradient Richardson number into the thermal to mechanical time scale ratio and model coefficients. The present model has been applied for the computation of stably and unstably stratified turbulent channel flows and the prediction results are directly compared to the DNS data.

• 대한수학회논문집
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• 제9권2호
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• pp.423-438
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• 1994

We employ the Galerkin method to solve the nonlinear Urysohn integral equation (1.1) x(t) = f(t) ＋ $∫_{D}$ k(t, s, x(s))ds (t $\in$ D), where D is a bounded domain in $R^{d}$ , the function f and k are known and x is the solution to be determined. We assume that D has a locally Lipschitz boundary ([1, p. 67]). We can rewrite (1.1) in operator notation as x = f ＋ Kx. We consider (1.1) as an operator equation on $L_{\infty$}$(D) and assume that K is defined on the closure $\Omega$ of a bounded open set $\Omega$ ⊂ $L_{\infty}$(D). Throughout our analysis we put the following assumptions on (1.1).(omitted)(1.1).(omitted)

• Journal of applied mathematics & informatics
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• 제34권1_2호
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• pp.1-7
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• 2016

Some properties of filters are studied with respect to a congru-ence of BE-algebras. The notion of θ-filters is introduced and these classes of filters are then characterized in terms of congruence classes. A bijection is obtained between the set of all θ-filters of a BE-algebra and the set of all filters of the respective BE-algebra of congruences classes.

• 대한수학회지
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• 제37권6호
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• pp.1031-1042
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• 2000

The equations prescribed in Ω⊂R(sup)n are called loaded, if they contain some operations of the traces of desired solution on manifolds (of dimension which is strongly less than n) from closure Ω. These equations result from approximations of nonlinear equations by linear ones, in the problems of optimal control when the control when the control actions depends on a part of independent variables, in investigations of the inverse problems and so on. In present work we study the nonlocal boundary value problems for first-order loaded differential operator equations. Criterion of unique solvability is established. We illustrate the obtained results by examples.

• 대한수학회지
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• 제47권4호
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• pp.735-742
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• 2010

In this paper, we define and study the concept of $\wedge^s_{\delta}$-closure operator and the associated topology $\tau^{\wedge}^s_{\delta}$ on a topological space (X, $\tau$) in terms of g.$\wedge^s_{\delta}$-sets.

• 충청수학회지
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• 제27권3호
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• pp.363-379
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• 2014

In this paper, introducing various separation axioms on a bi-GTS, it has been observed that such separation axioms actually unify the well-known separation axioms on topological spaces. Several characterizations of such separation properties of a bi-GTS are established in terms of ${\gamma}_{{\mu}_i,{\mu}_j}$-closure operator, generalized cluster sets of functions and graph of functions.

• Journal of applied mathematics & informatics
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• 제41권5호
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• pp.907-921
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• 2023

In this article, we are presenting and examining a subclass of Meromorphic univalent functions as stated by the Bessel function. We get disparities in terms of coefficients, properties of distortion, closure theorems, Hadamard product. Finally, for the class Σ^*(℘, ℓ, ℏ, τ, c), we obtain integral transformations.

• 지능정보연구
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• 제29권3호
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• pp.361-381
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• 2023

기업 부도 예측에 관한 연구는 재무정보를 중심으로 연구되어 왔다. 기업의 재무정보는 분기별로 갱신되기 때문에 실시간으로 기업의 폐업 가능성을 예측하는 데 있어 적시성이 부족하게 되는 문제가 발생한다. 이를 개선하고자 하는 평가 기업에서는 대상 기업의 건전성을 판단하기 위한 재무정보 외의 정보를 활용한 기업의 건전성을 판단하는 방법이 필요하다. 이를 위해 정보 기술의 발달로 기업에 대한 비재무정보 수집이 용이해지면서 기업 부도 예측에 재무정보 외의 추가적인 변수와 여러 가지 방법론을 적용하는 연구가 진행되어 왔으며, 이 중에서도 어떤 변수들이 기업의 부도를 예측하는데 영향을 주는지를 밝히는 것이 중요한 연구 과제가 되었다. 본 연구에서는 전자결제서비스를 이용하는 사업자의 폐업을 예측할 때 비재무정보를 구성하는 전자결제 정보들이 얼마나 영향을 미치는지를 살펴보았으며, 재무정보와 비재무정보 결합에 따른 폐업 예측 정확도 차이를 살펴보았다. 구체적으로, 재무정보 모형과 비재무정보 모형, 그리고 이를 결합한 모형으로 구성된 세 가지 연구 모형을 설계하였으며 Multi Layer Perceptron(MLP) 알고리즘을 포함한 여섯 가지 알고리즘으로 폐업 예측 정확도를 확인하였다. 재무정보와 비재무정보를 결합한 모형이 가장 높은 예측 정확도를 보였으며, 그 다음으로는 비재무정보 모형, 재무정보 모형의 순서로 예측 정확도가 확인되었다. 알고리즘별 폐업 예측 정확도는 여섯 가지의 알고리즘 중 XGBoost가 가장 높은 예측 정확도를 보였다. 사업자의 폐업 예측에 활용된 전체 87개의 변수를 대상으로 상대적 중요도를 살펴본 결과 폐업 예측에 중요하게 영향을 미친 변수는 상위 20개 중 70% 이상이 비재무정보인 것으로 확인되었다. 이를 통해 비재무정보의 전자결제 정보가 사업자의 폐업을 예측하는 중요한 변수임을 확인하였으며, 비재무 정보가 재무정보의 대안적 정보로서 활용할 수 있는 가능성 역시 살펴볼 수 있었다. 본 연구를 기반으로 사업자의 폐업을 예측할 수 있는 정보로서 비재무정보의 수집과 활용에 대한 중요성을 인식하고 기업의 의사결정에 활용할 수 있는 방안에 대해서도 다루었다.

• 대한수학회보
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• 제41권1호
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• pp.53-71
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• 2004

A certain subclass $T_{\Omega}(n,\;p,\;\lambda,\;\alpha)$ of starlike functions in the unit disk is introduced. The object of the present paper is to derive several interesting properties of functions belonging to the class $T_{\Omega}(n,\;p,\;\lambda,\;\alpha)$. Coefficient inequalities, distortion theorems and closure theorems of functions belonging to the class $T_{\Omega}(n,\;p,\;\lambda,\;\alpha)$ are determined. Also we obtain radii of convexity for the class $T_{\Omega}(n,\;p,\;\lambda,\;\alpha)$. Furthermore, integral operators and modified Hadamard products of several functions belonging to the class $T_{\Omega}(n,\;p,\;\lambda,\;\alpha)$ are studied here.