• Journal of applied mathematics & informatics
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• 제8권3호
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• pp.909-917
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• 2001

In this paper we define product between fuzzy ${H_v}-ideals$ of given ${H_v}-rings$. we consider the fundamental relation ${\gamma}^*$ defined on and ${H_v}-ring$ and give some properties of the fundamental relations and fundamental rings with respect to the product of fuzzy ${H_v}-ideals$.

• 충청수학회지
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• 제18권2호
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• pp.161-173
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• 2005

In this paper, we will introduce the folding on the connected sum of some types of manifolds which are determined by their fundamental group. Also, the fundamental group of the unfolding of the connected sum will be deduced some types of conditional foldings restricted on the elements of the fundamental groups are deduced. Theorems governing these relations will be achieved. Some applications in manufacturing are presented.

• 대한수학회보
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• 제40권1호
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• pp.1-8
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• 2003

In this paper, we further develop the weak polygroup theory, we define quotient weak polygroup and then the fundamental homomorphism theorem of group theory is derived in the context of weak polygroups. Also, we consider the fundamental relation $\beta$$^{*}$ defined on a weak polygroup and define a functor from the category of all weak polygroups into the category of all fundamental groups.s.

• Journal of applied mathematics & informatics
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• 제11권1_2호
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• pp.265-271
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• 2003

The purpose of this paper is to present certain results arising from product between fuzzy $H_{v}$-submodules. In particular, we consider the fundamental relation $\varepsilon$* defined on an $H_{v}$-module and give a property of the fundamental relations and fundamental modules with respect to the fuzzy product of $H_{v}$-modules.

• 호남수학학술지
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• 제23권1호
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• pp.59-66
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• 2001

A class of topological algebras, which we call it a fundamental one, has already been introduced to generalize the locally bounded and locally convex algebras. To prove the basic theorems on fundamental algebras, the first successful step is the new version of the Cohen factorization theorem. Here we recall it and prove some new results on fundamental topological algebras.

• 한국도로학회논문집
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• 제14권6호
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• pp.183-190
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• 2012

PURPOSES : The fundamental diagram provides basic information necessary in the analysis of traffic flow and highway operation. When traffic flow is congested, the density-flow points in the fundamental diagram are widely scattered and move in a stochastic manner. This paper investigates the pattern of density-flow point transitions and identifies car-following behaviors underlying the density-flow transitions. METHODS : From a microscopic analysis of 722 fundamental diagrams of NGSIM data, a total of 20 transition patterns of fundamental diagrams are identified. Prominent features of the transition patterns are explained by the behavior of the leader and follower. RESULTS : It is found out that the average speed and the speed difference between the leader and the follower critically determine the density-flow transition pattern. The density-flow path is very sensitive to the values of vehicle speed and spacing especially at low speed and high density such that most fluctuations in the fundamental diagram in the congested regime is due to the noise of speed and spacing variations. CONCLUSIONS : The result of this study suggests that the average speed, the speed difference between the leader and the follower, and the random variations of speed and spacing are dominant factors that explain the transition patterns of a fundamental diagram.

• 음성과학
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• 제15권2호
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• pp.169-176
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• 2008

This study was intended to analyze difference of vocal folds movements between upon wakeup and in several hours later in the morning. The difference of vocal fold movements was compared with fundamental frequency and a range of fundamental frequencies from maximum to minimum. The participants were 30 female adults between 20 and 29 years old. Voice samples were collected from their reading sentence (Jeong, 1993). The first sampling was conducted within 5 minutes after wakeup, while the second on 1 hour after the first sampling. Finally, the third voice sample was collected on 6 hours after the second sampling. The results of this study were as follows: First, fundamental frequency of the participants were by hour significantly time-dependent(F=7.843). Post-hoc multiple comparison (LSD) was conducted to determine when the difference could be observed. The result showed significant differences between upon wakeup and 6 hours later (p< .001) and between 1 hour later and 6 hours later (p< .05). Second, there were a significantly time-dependent ranges of fundamental frequencies of participants by hour (F=3.130). According to the results of the LSD analysis the significant differences in range of fundamental frequencies were found between upon wakeup and 1 hour later and also between wakeup and 6 hours later (p< .05). The results above indicate that vocal fold movements upon wakeup is different from those of several hours later.

• 대한수의학회지
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• 제59권1호
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• pp.37-42
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• 2019

Worldwide, avian influenza H9N2 viruses of different lineages are the most widespread viruses in poultry. However, to date, cases in Russia have not been documented. In this study, we report the first detection of a G1-like H9N2 virus from poultry sampled at live-bird markets in Russia (Far East region) during the winter of 2018 (isolate A/chicken/Amur_Russia/17/2018). We assume there has been further circulation of the A/chicken/Amur_Russia/17/2018 H9N2 virus in the Russian Far East with possible distribution to other regions or countries in 2018-2019.

• 대한교통학회지
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• 제22권3호
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• pp.95-105
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• 2004

교통기본도(Fundamental Diagram)는 교통류와 관련된 다양한 연구에서 중요한 요소로 생각되어져 왔다. 지금까지 다양한 형태의 교통기본도가 제시되었고 실제 데이터를 가장 잘 설명하는 교통기본도의 형태에 대해 많은 논의가 이루어졌지만, 서로 다른 형태의 교통기본도를 결정하는 원인에 대한 분석이 충분히 이루어지지 않고 있다. 본 연구는 서로 다른 지점과 교통조건에서 운전자의 행태차이를 이해하는데 중요한 파라메타로서 차간시간(time gap)을 소개하였고, 차간시간과 교통기본도의 형태와의 연관성을 분석하였다. 개별차량 검지기 자료를 토대로, 차간시간은 확률분포를 따르고 평균값은 지점에 따라 변화하는 것과 다른 통행속도에서 다른 차간시간을 보이는 것으로 분석되었다. 또한, 차간시간-속도 분포도의 3가지 형태들이 확인되었고 이것들은 교통류율-밀도 교통기본도로 전환되면 기존의 Greenberg, 역 ${\lambda}$, 전도된 V형태의 교통기본도와 일치하였다. 본 연구는 미시적 교통변수인 차간시간을 이용하여 교통기본도의 특징을 해석하였고, 운전자들의 행태에 관한 특성을 교통조건과 도로의 기하구조에 따라 설명하였다.

• 대한기계학회논문집B
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• 제21권10호
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• pp.1350-1362
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• 1997

An experimental study has been performed on vortex pairing under fundamental and subharmonic forcing with controlled initial phase differences through hot-wire measurements and a multi-smoke wire flow visualization. For the range of St$_{D}$ < 0.6, vortex pairing was controlled by means of fundamental and subharmonic forcing with varying initial phase differences. Much larger mixing rate was achieved by two-frequency forcing with a proper phase difference than one frequency forcing. As St$_{D}$ decreased, vortex pairing was limited to a narrow region of the initial phase difference between two disturbances and higher amplitudes of the fundamental and its subharmonic at the nozzle exit were required for more stable pairing. As the amplitude of the subharmonic at the nozzle exit increased for fixed St$_{D}$ and fundamental amplitude, the distribution of the subharmonic mode against the variation of the initial phase difference changed from a sine function form into a cusp-like form. Thus, vortex pairing can be controlled more precisely for the former case. For St$_{D}$ > 0.6, non-pairing advection of vortices due to the improper phase difference was sometimes observed in several fundamental forcing amplitudes when only the fundamental was applied. However, when its subharmonic was added, vortex pairing readily occurred. As the initial amplitude of this subharmonic increased, the position of vortex pairing moved upstream. This was thought to be due to the fact that the variation of the initial phase difference between the fundamental and its subharmonic has less effects on vortex pairing in the region of fundamental-only vortex pairing.pairing.