• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.728-732
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• 2008

본 연구는 운동 표상에 관한 뇌 메커니즘의 이해를 위해 fMRI를 이용한 측정 시스템을 개발하였다. 개발된 시스템의 검증을 위해 예비 실험을 시행하였다. fMRI task는 visual feedback을 제공하는 task와 차단하는 task 두 가지의 task로 구성되었다. 실험 결과 visual feedback이 제공되었을 때는 left superior orbital gyrus, bilateral precentral gyrus, left superior occipital gyrus, left supplementary motor area, right thalamus, right postcentral gyrus 그리고 right superior parietal lobule 같은 영역들이 활성화 되었다. Visual feedback이 차단되었을 때는 left precuneus, right middle temporal gyrus, bilateral supplementary motor area, right anterior cingulate cortex, left Inferior temporal gyrus, left insula lobe, right superior parietal lobule, bilateral postcentral gyrus 그리고 left precentral gyrus 같은 영역들이 활성화 되었다. 개발된 시스템을 통해서 visual feedback이 차단되었을 경우 운동 표상에 관한 뇌 메커니즘을 알아 볼 수 있었다.

• 인지과학
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• 제19권1호
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• pp.75-88
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• 2008

시각 장면은 중복적인 정보가 많이 포함되어 있다. 우리의 시각체계는 다양하고 중복적인 정보를 처리하기 위해 뇌 용적을 늘이기보다는 들어오는 외부 정보를 요약한다. 유사한 형태의 다양한 정보가 시각체계에 주어지면 시각체계는 정보의 통계적 특성을 추출해 낸다. 이런 통계적 표상의 대표적 형태가 바로 평균 표상이다. 평균 표상의 한 예로 시각 체계에서 계산해 내는 유사한 여러 크기들의 평균 크기를 들 수 있다. 평균 표상은 빠르고 정확하며 비교적 오랜 시간 지속되는 표상이고 평균 표상의 처리과정 또한 병렬적인 처리과정이다. 하지만 지금까지의 통계 표상에 관한 연구는 행동측정방법에 의한 연구였다. 따라서 본 연구는 기능적 자기 공명 영상 기법을 사용하여 통계 표상에 관한 신경기제를 찾고자 하였다. 사전 연구 결과들에 따르면 특정 자극을 연속하여 제시하였을 때 특정 자극을 담당하는 영역에서 자기 공명 영상 신호가 감소함을 알 수 있다. 본 연구에서는 이 반복 감소 현상을 사용하여 원들의 평균이 동일한 자극을 제시하였을 때 우측 후두 영역에서 유의미하게 자기 공명 영상 신호가 감소하는 것을 발견하였다. 이것은 우측 후두 영역이 시각자극에 대한 평균 표상을 처리하는 영역일 수 있음을 시사한다.

• 대한수학회논문집
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• 제29권4호
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• pp.527-538
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• 2014

Let K be a compact Hausdorff space, $\mathfrak{A}$ a commutative complex Banach algebra with identity and $\mathfrak{C}(\mathfrak{A})$ the set of characters of $\mathfrak{A}$. In this note, we study the class of functions $f:K{\rightarrow}\mathfrak{A}$ such that ${\Omega}_{\mathfrak{A}}{\circ}f$ is continuous, where ${\Omega}_{\mathfrak{A}}$ denotes the Gelfand representation of $\mathfrak{A}$. The inclusion relations between this class, the class of continuous functions, the class of bounded functions and the class of weakly continuous functions relative to the weak topology ${\sigma}(\mathfrak{A},\mathfrak{C}(\mathfrak{A}))$, are discussed. We also provide some results on its completeness under the norm defined by ${\mid}{\parallel}f{\parallel}{\mid}={\parallel}{\Omega}_{\mathfrak{A}}{\circ}f{\parallel}_{\infty}$.

• 대한수학회논문집
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• 제21권1호
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• pp.17-25
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• 2006

In this paper, we study the right regular representation $R_\Gamma$ of a finite group G on the vector space consisting of vector valued functions on ${\Gamma}/G$ with a subgroup r of G and give a trace formula using the work of M. -F. Vigneras.

• 음성과학
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• 제10권2호
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• pp.287-301
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• 2003

The purpose of this study was to examine whether the same vowel sounds are perceived differently by the two local dialect speakers, Seoul dialect speakers (SDS) and Kyungnam dialect speakers (KDS), whose vowel systems differ each other. In the first experiment SDS and KDS heard vowels synthesized in vowel space with F1 by F2 and categorized them into one of 10 Korean monophthongs. The results showed that SDS and KDS perceived the synthesized vowels differently. For example, /$\varepsilon$ versus /e/ contrast, ${\o}$/, and /y/ are differentiated by SDS, whereas they are perceptually confused by KDS. We also observed that /i/ could not be perceived unless the vowel synthesis included F3 or higher formants. In the second experiment SDS and KDS performed the similarity rating task of 10 synthesized Korean monophthongs. Two-dimensional MDS solution based on the similarity rating scores was obtained for each dialect group. The first dimension can be named 'vowel advancement' and the second 'vowel height'. The comparison of the two MDS solutions showed that the overall psychological distances among the vowels are shorter in KDS than SDS and that especially the distance between /$\Lambda$/ and /i/ is shorter in KDS than SDS. The result suggested that perception or mental representation of vowels depends on the vowel system of the listener's dialect or language. Further research problems were discussed in the final section.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1380-1388
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• 2013

The conventional graphical representation of the instantaneous compensation power flow for single-phase active power filters(APFs) simply represents the active power flow and the reactive power flow which flowing between the power source and the active filter / the load. But, this method does not provide the information about the rectification mode and the compensation mode of APFs, especially, the loss for each mode was not considered at all. This is very important to understand the compensation operation characteristics of APFs. Therefore, this paper proposes the graphical representation of the instantaneous compensation power flow for single-phase APFs considering the instantaneous rectification mode and the instantaneous inversion mode. Three cases are verified in this paper - without compensation, with compensation of the active power 'p' and the fundamental reactive power 'q', and with compensation of only the distorted power 'h'. To ensure the validity of the proposed approach, PSIM simulation is achieved. As a result, we could confirm that the proposed approach was easy to explain the instantaneous compensation power flow considering the instantaneous rectification mode and the instantaneous inversion mode of APFs, also, Total Harmonic Distortion(THD)/Power Factor (P.F) and Fast Fourier Transform(FFT) analysis were compared for each case.

• ETRI Journal
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• 제44권5호
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• pp.794-804
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• 2022

Transformer models have had a great impact on natural language processing (NLP) in recent years by realizing outstanding and efficient contextualized language models. Recent studies have used transformer-based language models for various NLP tasks, including Persian named entity recognition (NER). However, in complex tasks, for example, NER, it is difficult to determine which contextualized embedding will produce the best representation for the tasks. Considering the lack of comparative studies to investigate the use of different contextualized pretrained models with sequence modeling classifiers, we conducted a comparative study about using different classifiers and embedding models. In this paper, we use different transformer-based language models tuned with different classifiers, and we evaluate these models on the Persian NER task. We perform a comparative analysis to assess the impact of text representation and text classification methods on Persian NER performance. We train and evaluate the models on three different Persian NER datasets, that is, MoNa, Peyma, and Arman. Experimental results demonstrate that XLM-R with a linear layer and conditional random field (CRF) layer exhibited the best performance. This model achieved phrase-based F-measures of 70.04, 86.37, and 79.25 and word-based F scores of 78, 84.02, and 89.73 on the MoNa, Peyma, and Arman datasets, respectively. These results represent state-of-the-art performance on the Persian NER task.

• ETRI Journal
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• 제11권1호
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• pp.109-122
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• 1989

We developed new quadtree and octree representation schemes which reduce the storage requirements from exponential to polynomial. The new schemes not only lessen the large storage requirements of the existing quadtree and octree representation schemes but guarantee an exact representation of the original object. These are made possible by adopting a new set of termination conditions that ensure finiteness of the quadtree and octree during the decomposition. These new data structures are analyzed theoretically and tested empirically. For space complexity, we analyzed its best case, worst case, and average case. Given an $n_e$-gon, we show that the expected number of nodes in our quadtree isO($$$n_e^1.292$) For a polyhedron with $n_f$ faces, the expected number of nodes in the new octree is O($$$n_f^1.667$). For time complexity, we again analyzed the best, worst, and average cases for constructing such quadtree and octree and find the average to be the same as those of the space complexity. Finally, random $n_e$- gons are generated as test data. Regression equations are fitted and are shown to support the claims on the average case performance.

• 호남수학학술지
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• 제21권1호
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• pp.75-95
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• 1999

Dimensions of irreducible $so_5(F)$-modules over an algebraically closed field F of characteristics p > 2 shall be obtained. It turns out that they should be coincident with $p^{m}$, where 2m is the dimension of coadjoint orbits of ${\chi}{\in}so_5(F)^*{\backslash}0$ as Premet asserted. But there is no subregular point for $g=sp_4(F)=so_5(F)$ over F.

• Journal of applied mathematics & informatics
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• 제40권1_2호
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• pp.205-213
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• 2022

In this paper we give a simple and direct proof of an Euler integral representation for a special class of _q+1F_q,k k-hypergeometric functions for q ≥ 2. The values of certain ₃F_2,k and ₄F_3,k functions at $x=\frac{1}{k}$, some of which can be derived using other methods. We may conclude that for k = 1 the results are reduced to [3].