• Journal of applied mathematics & informatics
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• 제7권3호
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• pp.1029-1038
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• 2000

In this paper, we show that if x is a positively Lyapunov stable point of an expansive homeomorphism with the pseudo-orbit-tracing-property, then x is a periodic point or its positive limit set consists of only one periodic orbit, and their periods are predictable. We give a necessary and sufficient condition that a basic set is to be a sink or source. Also, we consider some dynamical properties of basic sets.

• ETRI Journal
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• 제27권2호
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• pp.133-139
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• 2005

A monolithic microwave integrated circuit (MMIC) chip set consisting of a power amplifier, a driver amplifier, and a frequency doubler has been developed for automotive radar systems at 77 GHz. The chip set was fabricated using a 0.15 ${\mu}$ gate-length InGaAs/InAlAs/GaAs metamorphic high electron mobility transistor (mHEMT) process based on a 4-inch substrate. The power amplifier demonstrated a measured small signal gain of over 20 dB from 76 to 77 GHz with 15.5 dBm output power. The chip size is 2mm${\times}$ 2mm. The driver amplifier exhibited a gain of 23 dB over a 76 to 77 GHz band with an output power of 13 dBm. The chip size is 2.1mm${\times}$ 2mm. The frequency doubler achieved an output power of -6 dBm at 76.5 GHz with a conversion gain of -16 dB for an input power of 10 dBm and a 38.25 GHz input frequency. The chip size is 1.2mm ${\times}$ 1.2mm. This MMIC chip set is suitable for the 77 GHz automotive radar systems and related applications in a W-band.

• 영재교육연구
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• 제5권2호
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• pp.37-54
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• 1995

The radical development of modern mathematics is due to the appearance of Collection Theory by George Cantor. The Set Theory is independent as an area and also closely interrelated with other areas. So its content becomes a common sense and a basic part across the whole area of modern mathematics. Accordingly, the basic element of modern mathematics is helping young children get familiar with set as early as possible. The thinking of set by which children can categorize, make partial sets and correspondences, understand the general characteristic, and conceptualize the discovered relationships is very important for young children. At this point where the Math education for young children is emphasized under the influence of the modernization movement of Math education, the systematic education for building up the set concept as the basic background of number concept during the early childhood is required. On current mathematics education for young children, graphs, the foundation of geometry, time, and patterns have been included in the traditional and practical content related to numbers. However, the education on collection which is the foundation of number concept is insufficient. A study shows that the level of young children's understanding on set is quite high, but the set concept isn't reflected in current Math curriculum for young children. And basic activities neccesary on building up the set concept, such as categorization, comparison, etc. are conducted in kindergardens but unsatisfactory because of those kindergarden teachers' premature understanding on the set concept. In conclusion, the curriculum for young children should be reorganized based on the set concept as the kernel concept. Also, the reappraisal of the training curriculum and the supplementary efucation for kindergarden teachers are urgent for raising the teaching ability of those kindergarden teachers.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1489-1502
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• 2019

This work introduces a novel unweighted combination method (UCSS) for business failure perdition (BFP). With considering features of BFP in the age of big data, UCSS integrates the quantitative and qualitative analysis by utilizing soft set theory (SS). We adopt the conventional expert system (ES) as the basic qualitative classifier, the logistic regression model (LR) and the support vector machine (SVM) as basic quantitative classifiers. Unlike other traditional combination methods, we employ soft set theory to integrate the results of each basic classifier without weighting. In this way, UCSS inherits the advantages of ES, LR, SVM, and SS. To verify the performance of UCSS, it is applied to real datasets. We adopt ES, LR, SVM, combination models utilizing the equal weight approach (CMEW), neural network algorithm (CMNN), rough set and D-S evidence theory (CMRD), and the receiver operating characteristic curve (ROC) and SS (CFBSS) as benchmarks. The superior performance of UCSS has been verified by the empirical experiments.

• Annals of Fuzzy Mathematics and Informatics
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• 제16권3호
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• pp.261-284
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• 2018

In this paper, we recall the definition of soft set, fuzzy soft set, hesitant fuzzy set and hesitant fuzzy soft set and some of their examples. We define the concept of hesitant fuzzy soft multiset which combines hesitant fuzzy soft set and soft multiset theory. We also define basic terms in hesitant fuzzy soft multiset with relevant examples. Some basic operations such as restricted intersection, extended intersection, union, restricted union, AND-product and OR-product and their properties are given, supported with illustrative examples. We finally establish some important results, including De Morgan's inclusions and laws.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2717-2722
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• 2009

The use of the classification and regression tree (CART) methodology was studied in a quantitative structure-activity relationship (QSAR) context on a data set consisting of the binding affinities of 39 imidazobenzodiazepines for the α1 benzodiazepine receptor. The 3-D structures of these compounds were optimized using HyperChem software with semiempirical AM1 optimization method. After optimization a set of 1481 zero-to three-dimentional descriptors was calculated for each molecule in the data set. The response (dependent variable) in the tree model consisted of the binding affinities of drugs. Three descriptors (two topological and one 3D-Morse descriptors) were applied in the final tree structure to describe the binding affinities. The mean relative error percent for the data set is 3.20%, compared with a previous model with mean relative error percent of 6.63%. To evaluate the predictive power of CART cross validation method was also performed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.28-31
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• 1996

A bag is a set-like entity which can contain repeated elements. Fuzzy bags have been studied by Yager, who defined their basic relations and operations. However, his definitions of the basic relations and operations are inconsistent with the corresponding relations and operations for ordinary fuzzy sets. The present paper presents new basic relations and operations of fuzzy bags using a grade sequence for each element of the universal set. Moreover the .alpha.-cut, t-norms, the extension principle, and the composition of fuzzy bag relations are described.

• Journal of applied mathematics & informatics
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• 제35권3_4호
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• pp.331-347
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• 2017

Soft sets are fantastic mathematical tools to handle imprecise and uncertain information in complicated situations. In this paper, we defined the hybrid structure which is the combination of soft set and complex number representation of intuitionistic fuzzy set. We defined basic set theoretic operations such as complement, union, intersection, restricted union, restricted intersection etc. for this hybrid structure. Moreover, we developed this theory to establish some more set theoretic operations like Disjunctive sum, difference, product, conjugate etc.

• 대한화학회지
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• 제51권4호
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• pp.365-374
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• 2007

본 연구에서는 고등학교 3학년 학생 100명을 대상으로 세트화 된 질문지를 사용하여 화학 평형 이 동시 반응 속도 변화에 대한 학생들의 이해 정도를 조사하고, 반응 속도의 기본 개념에 대한 질문이 화학 평 형 이동시의 반응 속도 변화를 이해하는데 도움이 되는지를 조사하였다. 질문지는 A, B, A' 세 개의 세트로 구 성하였으며, A, B, A' 순서대로 응답하도록 하였다. A세트는 화학 평형 이동시의 반응 속도 변화에 대한 문항, B세 트는 반응 속도의 기본 개념에 대한 문항으로 되어 있으며, A'세트는 A세트와 동일한 문항으로 되어 있다. 학 생들의 응답을 분석한 결과 화학 평형 이동시 반응 속도 변화에 대해 정반응 속도 변화보다 역반응 속도 변 화에 대한 이해가 낮았다. 그리고 평형에서 농도 변화에 따른 반응 속도 변화에 대한 이해는 어느 정도 되어 있으나 온도 변화에 따른 반응 속도 변화에 대한 이해도는 아주 낮았다. 그러나 반응 속도 기본 개념에 대한 정답률은 아주 높아 평형 이동시 반응 속도 변화에 대한 낮은 이해도는 반응 속도에 대한 기본 개념이 부족 한 것이 아니라 이를 화학 평형 이동에 제대로 연계시키지 못한 결과로 생각된다. A세트와 A'세트의 정답률 을 비교한 결과 A'세트의 정답률이 통계적으로 유의미하게 높게 나타나 B세트의 문항이 A'세트의 문항 해결 에 도움이 된 것으로 해석할 수 있다. 그러므로 이와 같은 세트화 된 질문지가 학생들의 개념 연결에 도움을 줄 수 있는 가능성을 확인하였다.

• Journal of applied mathematics & informatics
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• 제8권2호
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• pp.635-640
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• 2001

Let X be a T-admissible space and A(x) be the set of all admissible fibers at x∈X. In this paper, we introduce some basic concepts, properties, and known results about set-valued maps, hyperspaces and especially T-admissible spaces. And then, we construct a certain set-valued map(Theorem 2.3) and an arc from {x} to X∈A(x) in use of the set-valued maps(Theorem 2.3 through Theorem 2.7).