• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1489-1496
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• 2013

Consider the ROC surface which is a generalization of the ROC curve for three-class diagnostic problems. In this work, we propose ve criteria for the three-class ROC surface by extending the Youden index, the sum of sensitivity and specificity, the maximum vertical distance, the amended closest-to-(0,1) and the true rate. It may be concluded that these five criteria can be expressed as a function of two Kolmogorov-Smirnov statistics. A paired optimal thresholds could be obtained simultaneously from the ROC surface. It is found that the paired optimal thresholds selected from the ROC surface are equivalent to the two optimal thresholds found from the two ROC curves.

• 호남수학학술지
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• 제31권4호
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• pp.591-599
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• 2009

For given ${\alpha},{\omega}\;{\in}\;{\mathbb{R}}$ and ${\beta}$ > 1, let $T_{{\beta},{\alpha},{\omega}}$ be the skew-product transformation on the torus, [0, 1) ${\times}$ [0, 1) defined by (x, y) ${\longmapsto}\;({\beta}x,y+{\alpha}x+{\omega})$ (mod 1). In this paper, we give a criterion of ergodicity and weakly mixing for the transformation $T_{{\beta},{\alpha},{\omega}}$ when the natural extension of the given ${\beta}$-transformation can be viewed as a generalized baker's transformation, i.e., they flatten and stretch and then cut and stack a two-dimensional domain. This is a generalization of theorems in [10].

• 공학교육연구
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• 제20권5호
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• pp.43-49
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• 2017

This paper deals with inter-relationship change of women's university students on the process of SW development project using social collaboration tool. Inter-relationship is one of the basic vocational competency in NCS(National Competency Standards) of Korea. We redesigned the curriculum of "Software Engineering" subject for this study and composed the project teams of students to develop software. The details of inter-relationship are satisfaction, communication, faith, friendliness, sensitivity, openness and consideration. From the result of this study, faith, openness and consideration have positive effect but satisfaction, communication, friendliness and sensitivity have no meaningful effect. The surveys were conducted in the beginning of semester and the same surveys were conducted again in the end of semester. The results were verified by paired t-test with SPSS 18.0. It is significant that the using of social collaboration tool for team project has positive effect on inter-relationship change, especially faith of women's university students. This study has some limitations for generalization but has meaning as new trial to enlarge the basic vocational competency of students in major subject, "Software Engineering". We expect new study for inter-relationship change of students to evaluate generality based on the proposed method in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.824-826
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• 1999

In this paper, we design an Fuzzy-Neural Networks(FNN) by means of divisions of fuzzy input space with multi-input variables. Fuzzy input space of Yamakawa's FNN is divided by each separated input variable, but that of the proposed FNN is divided by mutually combined input variables. The membership functions of the proposed FNN use both triangular and gaussian membership types. The parameters such as apexes of membership functions, learning rates, momentum coefficients, weighting value, and slope are adjusted using genetic algorithms. Also, an aggregate objective function(performance index) with weighting value is utilized to achieve a sound balance between approximation and generalization abilities of the model. To evaluate the performance of the proposed model, we use the data of sewage treatment process.

• 대한수학회보
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• 제54권3호
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• pp.799-816
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• 2017

In this paper, we investigate the Bonnesen-style Aleksandrov-Fenchel inequalities in ${\mathbb{R}}^n$, which are the generalization of known Bonnesen-style inequalities. We first define the i-th symmetric mixed homothetic deficit ${\Delta}_i(K,L)$ and its special case, the i-th Aleksandrov-Fenchel isoperimetric deficit ${\Delta}_i(K)$. Secondly, we obtain some lower bounds of (n - 1)-th Aleksandrov Fenchel isoperimetric deficit ${\Delta}_{n-1}(K)$. Theorem 4 strengthens Groemer's result. As direct consequences, the stronger isoperimetric inequalities are established when n = 2 and n = 3. Finally, the reverse Bonnesen-style Aleksandrov-Fenchel inequalities are obtained. As a consequence, the new reverse Bonnesen-style inequality is obtained.

• 호남수학학술지
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• 제31권4호
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• pp.463-478
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• 2009

Let k be an imaginary quadratic field, ℌ the complex upper half plane, and let ${\tau}{\in}k{\cap}$ℌ, q = exp(${\pi}i{\tau}$). And let n, t be positive integers with $1{\leq}t{\leq}n-1$. Then $q^{{\frac{n}{12}}-{\frac{t}{2}}+{\frac{t^2}{2n}}}{\prod}^{\infty}_{m=1}(1-q^{nm-t})(1-q^{nm-(n-t)})$ is an algebraic number [10]. As a generalization of this result, we find several infinite series and products giving algebraic numbers using Ramanujan's $_{1{\psi}1}$ summation. These are also related to Rogers-Ramanujan continued fractions.

• 전기학회논문지
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• 제65권12호
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• pp.2145-2152
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• 2016

Internet generalization has led to increased demands for Internet banking. Various security programs to protect authentication information are being developed; however, these programs cannot protect the wireless communication sections of wireless keyboards. In particular, vulnerabilities have been reported in the radio communication sections of 27 MHz wireless keyboards. In this paper, we explain how to analyze M's 27 MHz wireless keyboard. We also experimentally show that an attacker can acquire authentication information during domestic Internet banking using a 27 MHz wireless keyboard. To do this, we set up an experimental encironment to analyze the electromagnetic signal of a 27 MHz wireless keyboard.

• 대한수학회보
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• 제56권2호
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• pp.521-533
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• 2019

In this paper, we define a mean of two positive numbers called the k-golden mean and study some properties of it. Especially, we show that the 2-golden mean refines the harmonic and the geometric means. As an application, we define the k-golden ratio and give some properties of it as an generalization of the golden ratio. Furthermore, we define the matrix k-golden mean of two positive-definite matrices and give some properties of it. This is an improvement of Lim's results [2] for which the matrix golden mean.

• 대한안전경영과학회지
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• 제15권1호
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• pp.193-198
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• 2013

Warehouse Management System was a helper of business in past, but it is perceived as a core competitive power and a tool for generating new business. It have been come out some new prospects for WMS due to generalization of global outsourcing and extension of the range of supply chain. In China, H automobile company construct the new WMS for providing the production extension and increment of part demand for A/S. This paper deals with the location management in warehouse, warehouse management, delivery management of goods from a warehouse, inventory management organizing WMS for construction of A/S warehouse in H motor in China. Then we identified the several problems of existing warehouse and constructed the driving organization and methods for overcoming these problems. We continually gather data for analysing the effects of new A/S warehouse and WMS construction.

• 대한수학회보
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• 제45권1호
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• pp.59-66
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• 2008

Keskin and Harmanci defined the family B(M,X) = ${A{\leq}M|{\exists}Y{\leq}X,{\exists}f{\in}Hom_R(M,X/Y),\;Ker\;f/A{\ll}M/A}$. And Orhan and Keskin generalized projective modules via the class B(M, X). In this note we introduce X-local summands and X-hollow modules via the class B(M, X). Let R be a right perfect ring and let M be an X-lifting module. We prove that if every co-closed submodule of any projective module P contains Rad(P), then M has an indecomposable decomposition. This result is a generalization of Kuratomi and Chang's result [9, Theorem 3.4]. Let X be an R-module. We also prove that for an X-hollow module H such that every non-zero direct summand K of H with $K{\in}B$(H, X), if $H{\oplus}H$ has the internal exchange property, then H has a local endomorphism ring.