• 제목/요약/키워드: index pair

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A Study on the Performance of Similarity Indices and its Relationship with Link Prediction: a Two-State Random Network Case

  • Ahn, Min-Woo;Jung, Woo-Sung
    • Journal of the Korean Physical Society
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    • 제73권10호
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    • pp.1589-1595
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    • 2018
  • Similarity index measures the topological proximity of node pairs in a complex network. Numerous similarity indices have been defined and investigated, but the dependency of structure on the performance of similarity indices has not been sufficiently investigated. In this study, we investigated the relationship between the performance of similarity indices and structural properties of a network by employing a two-state random network. A node in a two-state network has binary types that are initially given, and a connection probability is determined from the state of the node pair. The performances of similarity indices are affected by the number of links and the ratio of intra-connections to inter-connections. Similarity indices have different characteristics depending on their type. Local indices perform well in small-size networks and do not depend on whether the structure is intra-dominant or inter-dominant. In contrast, global indices perform better in large-size networks, and some such indices do not perform well in an inter-dominant structure. We also found that link prediction performance and the performance of similarity are correlated in both model networks and empirical networks. This relationship implies that link prediction performance can be used as an approximation for the performance of the similarity index when information about node type is unavailable. This relationship may help to find the appropriate index for given networks.

SOME GROWTH ASPECTS OF SPECIAL TYPE OF DIFFERENTIAL POLYNOMIAL GENERATED BY ENTIRE AND MEROMORPHIC FUNCTIONS ON THE BASIS OF THEIR RELATIVE (p, q)-TH ORDERS

  • Biswas, Tanmay
    • Korean Journal of Mathematics
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    • 제27권4호
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    • pp.899-927
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    • 2019
  • In this paper we establish some results depending on the comparative growth properties of composite entire and meromorphic functions using relative (p, q)-th order and relative (p, q)-th lower order where p, q are any two positive integers and that of a special type of differential polynomial generated by one of the factors.

MEASURES OF COMPARATIVE GROWTH ANALYSIS OF COMPOSITE ENTIRE FUNCTIONS ON THE BASIS OF THEIR RELATIVE (p, q)-TH TYPE AND RELATIVE (p, q)-TH WEAK TYPE

  • Biswas, Tanmay
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제26권1호
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    • pp.13-33
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    • 2019
  • The main aim of this paper is to establish some comparative growth properties of composite entire functions on the basis of their relative (p, q)-th order, relative (p, q)-th lower order, relative (p, q)-th type, relative (p, q)-th weak type of entire function with respect to another entire function where p and q are any two positive integers.

The Line n-sigraph of a Symmetric n-sigraph-V

  • Reddy, P. Siva Kota;Nagaraja, K.M.;Geetha, M.C.
    • Kyungpook Mathematical Journal
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    • 제54권1호
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    • pp.95-101
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    • 2014
  • An n-tuple ($a_1,a_2,{\ldots},a_n$) is symmetric, if $a_k$ = $a_{n-k+1}$, $1{\leq}k{\leq}n$. Let $H_n$ = {$(a_1,a_2,{\ldots},a_n)$ ; $a_k$ ${\in}$ {+,-}, $a_k$ = $a_{n-k+1}$, $1{\leq}k{\leq}n$} be the set of all symmetric n-tuples. A symmetric n-sigraph (symmetric n-marked graph) is an ordered pair $S_n$ = (G,${\sigma}$) ($S_n$ = (G,${\mu}$)), where G = (V,E) is a graph called the underlying graph of $S_n$ and ${\sigma}$:E ${\rightarrow}H_n({\mu}:V{\rightarrow}H_n)$ is a function. The restricted super line graph of index r of a graph G, denoted by $\mathcal{R}\mathcal{L}_r$(G). The vertices of $\mathcal{R}\mathcal{L}_r$(G) are the r-subsets of E(G) and two vertices P = ${p_1,p_2,{\ldots},p_r}$ and Q = ${q_1,q_2,{\ldots},q_r}$ are adjacent if there exists exactly one pair of edges, say $p_i$ and $q_j$, where $1{\leq}i$, $j{\leq}r$, that are adjacent edges in G. Analogously, one can define the restricted super line symmetric n-sigraph of index r of a symmetric n-sigraph $S_n$ = (G,${\sigma}$) as a symmetric n-sigraph $\mathcal{R}\mathcal{L}_r$($S_n$) = ($\mathcal{R}\mathcal{L}_r(G)$, ${\sigma}$'), where $\mathcal{R}\mathcal{L}_r(G)$ is the underlying graph of $\mathcal{R}\mathcal{L}_r(S_n)$, where for any edge PQ in $\mathcal{R}\mathcal{L}_r(S_n)$, ${\sigma}^{\prime}(PQ)$=${\sigma}(P){\sigma}(Q)$. It is shown that for any symmetric n-sigraph $S_n$, its $\mathcal{R}\mathcal{L}_r(S_n)$ is i-balanced and we offer a structural characterization of super line symmetric n-sigraphs of index r. Further, we characterize symmetric n-sigraphs $S_n$ for which $\mathcal{R}\mathcal{L}_r(S_n)$~$\mathcal{L}_r(S_n)$ and $$\mathcal{R}\mathcal{L}_r(S_n){\sim_=}\mathcal{L}_r(S_n)$$, where ~ and $$\sim_=$$ denotes switching equivalence and isomorphism and $\mathcal{R}\mathcal{L}_r(S_n)$ and $\mathcal{L}_r(S_n)$ are denotes the restricted super line symmetric n-sigraph of index r and super line symmetric n-sigraph of index r of $S_n$ respectively.

KOSPI 200과 S&P 500 주가지수 선물의 상대적 가치를 이용한 거래시스템 개발 (Developing a Trading System using the Relative Value between KOSPI 200 and S&P 500 Stock Index Futures)

  • 김영민;이석준
    • 경영과정보연구
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    • 제33권1호
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    • pp.45-63
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    • 2014
  • 주식시장에서 트레이딩 시스템(trading system)은 투자 위험을 줄이면서 수익을 극대화하기 위해 일정한 규칙을 컴퓨터에 적용하여 기계적으로 거래를 실행하는 자동매매시스템이다. 그러나 단일 자산을 거래 대상으로 하는 트레이딩 시스템 개발은 그 자산의 움직임에 의해 수익 구조가 결정되는 문제점을 가지고 있기 때문에 위험을 초래할 우려가 존재한다. 따라서 두 자산 간 상대적 가치를 활용하여 한 자산의 위험 발생 시 다른 자산의 거래를 통해 안정적인 수익을 창출할 수 있는 트레이딩 시스템 개발에 대해 주목할 필요가 있다. 본 연구에서는 두 개의 주가지수 선물 간의 상대적 가치를 이용한 규칙기반 트레이딩 시스템을 개발하는 것이 목적이다. 이를 위해 차익거래 전략 시 활용되는 두 자산의 가격비율을 기반으로 기술적 지표(technical indicator)들을 생성하고, 데이터 마이닝 기법인 러프 집합 분석을 이용하여 거래규칙을 생성하였다. 생성된 거래규칙의 유용성을 확인하기 위해 슬라이딩 윈도우(sliding window) 방법을 사용하여 거래 시뮬레이션을 적용하였으며, KOSPI 200 지수선물과 S&P 500 지수선물을 분석 대상으로 선정하여 성과를 측정하였다. 실험 결과, 제안한 시스템이 시장의 흐름과 상관없이 절대적인 수익을 발생하는 것을 확인 할 수 있었다.

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Geometric Sensitivity Index for the GNSS Using Inner Products of Line of Sight Vectors

  • Won, Dae Hee;Ahn, Jongsun;Sung, Sangkyung;Lee, Chulsoo;Bu, Sungchun;Jang, Jeagyu;Lee, Young Jae
    • International Journal of Aeronautical and Space Sciences
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    • 제16권3호
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    • pp.437-444
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    • 2015
  • Satellite selection and exclusion techniques have been applied to the global navigation satellite system (GNSS) with the aim of achieving a balance between navigational performance and computational efficiency. Conventional approaches to satellite selection based on the best dilution of precision (DOP) are excessively computational and complicated. This paper proposes a new method that applies a geometric sensitivity index of individual GNSS satellites. The sensitivity index is derived using the inner product of the line of sight (LOS) vector of each satellite. First, the LOS vector is computed, which accounts for the geometry between the satellite and user positions. Second, the inner product of each pair of LOS vectors is calculated, which indicates the proximities of the satellites to one another. The proximity can be determined according to the sensitivity of each satellite. A post-processing test was conducted to verify the reliability of the proposed method. The proposed index and the results of a conventional approach that measures the dilution of precision (DOP) were compared. The test results demonstrate that the proposed index produces results that are within 96% of those of the conventional approach and reduces the computational burden. This index can be utilized to estimate the sensitivity of individual satellites, obtaining a navigation solution. Therefore, the proposed index applies to satellite selection and exclusion as well as to the sensitivity analyses of multiple GNSS applications.

단어 및 단어쌍 별 빈도수를 이용한 문서간 유사도 측정 (Measurement of Document Similarity using Word and Word-Pair Frequencies)

  • 김혜숙;박상철;김수형
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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    • pp.1311-1314
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    • 2003
  • In this paper, we propose a method to measure document similarity. First, we have exploited single-term method that extracts nouns by using a lexical analyzer as a preprocessing step to match one index to one noun. In spite of irrelevance between documents, possibility of increasing document similarity is high with this method. For this reason, a term-phrase method has been reported. This method constructs co-occurrence between two words as an index to measure document similarity. In this paper, we tried another method that combine these two methods to compensate the problems in these two methods. Six types of features are extracted from two input documents, and they are fed into a neural network to calculate the final value of document similarity. Reliability of our method has been proved by an experiment of document retrieval.

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열적 확산 코어 광섬유 브래그 격자의 스펙트럼 특성 (Spectral characteristics of the thermally expanded core fiber Bragg grating)

  • 이재범;윤재순;박동영;김형찬;최기선;백세종;임기건;김광택
    • 한국광학회:학술대회논문집
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    • 한국광학회 2006년도 하계학술발표회 논문집
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    • pp.521-522
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    • 2006
  • Thermally expanded core fiber (TEC-fiber) Bragg gratings have been fabricated and their transmission spectrums have been analyzed. The measured spectrum shows the characteristic peak splitting caused by the grating pair formed over the expanded section that has the effective index axial distribution, which could be employed for high resolution fiber sensors. An analysis on the spectrum can also give useful informations on the effective index profile of the TEC-fiber.

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