• Title/Summary/Keyword: N-tuple

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Unequal Error Control Properties of Convolutional Codes (길쌈부호의 부등오류제어 특성)

  • Lee, Soo-In;Lee, Sang-Gon;Moon, Sang-Jae
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.2
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    • pp.1-8
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    • 1990
  • The unequal bit-error control of rate r=b/n binary convolutional code is analyzed. The error protection afforded to each digit of the viterbi decoded b-tuple information word can be different from that afforded to other digit. The property of the unequal protection can be applied for improvement of SNR in transmitting sampled data of DPCM system.

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TWO-SIDED BEST SIMULTANEOUS APPROXIMATION

  • Rhee, Hyang Joo
    • Journal of the Chungcheong Mathematical Society
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    • v.23 no.4
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    • pp.705-710
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    • 2010
  • Let $C_1(X)$ be a normed linear space over ${\mathbb{R}}^m$, and S be an n-dimensional subspace of $C_1(X)$ with spaned by {$s_1,{\cdots},s_n$}. For each ${\ell}$- tuple vectors F in $C_1(X)$, the two-sided best simultaneous approximation problem is $$\min_{s{\in}S}\;\max\limits_{i=1}^\ell\{{\parallel}f_i-s{\parallel}_1\}$$. A $s{\in}S$ attaining the above minimum is called a two-sided best simultaneous approximation or a Chebyshev center for $F=\{f_1,{\cdots},f_{\ell}\}$ from S. This paper is concerned with algorithm for calculating two-sided best simultaneous approximation, in the case of continuous functions.

Phase Offset Enumeration Method with Error Detection and Its Application to Synchronization of PN Sequences

  • Song Young-Joan
    • Journal of electromagnetic engineering and science
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    • v.5 no.1
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    • pp.26-30
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    • 2005
  • It is important to know phase offsets of PN(Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to making a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration for an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time performance of the proposed scheme was derived analytically. Since this synchronization scheme can be realized by using simple circuit and acquires very rapid acquisition in high SNR but shows performance degradation in low SNR, it can be especially useful in indoor and office environments.

Equivalence of Cyclic p-squared Actions on Handlebodies

  • Prince-Lubawy, Jesse
    • Kyungpook Mathematical Journal
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    • v.58 no.3
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    • pp.573-581
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    • 2018
  • In this paper we consider all orientation-preserving ${\mathbb{Z}}_{p^2}$-actions on 3-dimensional handlebodies $V_g$ of genus g > 0 for p an odd prime. To do so, we examine particular graphs of groups (${\Gamma}(v)$, G(v)) in canonical form for some 5-tuple v = (r, s, t, m, n) with r + s + t + m > 0. These graphs of groups correspond to the handlebody orbifolds V (${\Gamma}(v)$, G(v)) that are homeomorphic to the quotient spaces $V_g/{\mathbb{Z}}_{p^2}$ of genus less than or equal to g. This algebraic characterization is used to enumerate the total number of ${\mathbb{Z}}_{p^2}$-actions on such handlebodies, up to equivalence.

DISCRETE SIMULTANEOUS ℓ1m-APPROXIMATION

  • RHEE, HYANG J.
    • Honam Mathematical Journal
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    • v.27 no.1
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    • pp.69-76
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    • 2005
  • The aim of this work is to generalize $L_1$-approximation in order to apply them to a discrete approximation. In $L_1$-approximation, we use the norm given by $${\parallel}f{\parallel}_1={\int}{\mid}f{\mid}d{\mu}$$ where ${\mu}$ a non-atomic positive measure. In this paper, we go to the other extreme and consider measure ${\mu}$ which is purely atomic. In fact we shall assume that ${\mu}$ has exactly m atoms. For any ${\ell}$-tuple $b^1,\;{\cdots},\;b^{\ell}{\in}{\mathbb{R}}^m$, we defined the ${\ell}^m_1{w}$-norn, and consider $s^*{\in}S$ such that, for any $b^1,\;{\cdots},\;b^{\ell}{\in}{\mathbb{R}}^m$, $$\array{min&max\\{s{\in}S}&{1{\leq}i{\leq}{\ell}}}\;{\parallel}b^i-s{\parallel}_w$$, where S is a n-dimensional subspace of ${\mathbb{R}}^m$. The $s^*$ is called the Chebyshev center or a discrete simultaneous ${\ell}^m_1$-approximation from the finite dimensional subspace.

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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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    • v.54 no.1
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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.

A study on the effectiveness of BOM(Bill of Material) data management (BOM (Bill of Material)의 효과성 분석 모형 연구)

  • 강영신;이춘열
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1994.04a
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    • pp.728-736
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    • 1994
  • 본 연구는 MRP(Material Requirement System) 시스템의 기본 요소인 BOM(Bill of Material)의 효과성 분석을 목적으로 한다. BOM은 부품의 구성 관계를 나타내는 표로서, 근자에는 모듈화의 개념이 도입된 Modular BOM이 제시되고 있다. Modular BOM은 부품의 구성 관계를 모듈화 함으로써 이들을 보다 편리하게 관리하고, 기존에 사용되어 오던 구조형 BOM의 불편함, 단점 등을 보완한다. 본 연구는 기존의 구조형 BOM과 modular BOM을 데이타베이스 관리면에서 분석함으로서, 모듈화한 BOM이 데이타 관리면에서 지니는 효과성을 분석하였다. 데이타 관리의 효과성 분석은 BOM 데이타 관리면에서 지니는 효과성을 분석하였다. 데이타 관리의 효과성 분석은 BOM 데이타베이스의 제품구성을 관계형 데이타베이스의 레코드 (또는 tuple)로 표현 함으로서, 특정 부분품으로 구성된 완제품들을 나타내기 위해 필요한 레코드 수를 기초로 하여 수행되었다. 이상의 논리에 근거하여 본 연구는 다음과 같은 데이타 관리 관점에서 분석한다. 1. 제품구성 표시를 위한 BOM 데이타베이스의 구성 레코드 수의 비교, 2. 새로운 제품의 추가나 기 제품의 제품구성 변경에 따른 갱신의 용이성 본 연구에서는 분석의 편의를 위하여 BOM 구성이 레벨을 무시한 단순형태의 2단계 BOM을 분석 대상으로 한다. BOM데이타 베이스 관리의 효과성은 제시된 레코드 수에 기초하여 데이타베이스의 규모와 변경 용이성의 측정 모형을 수립하고, 이들 모형을 modular BOM과 구조형 BOM에 적용함으로서 수행 되었다.

Online Information Sources of Coronavirus Using Webometric Big Data (코로나19 사태와 온라인 정보의 다양성 연구 - 빅데이터를 활용한 글로벌 접근법)

  • Park, Han Woo;Kim, Ji-Eun;Zhu, Yu-Peng
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.11
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    • pp.728-739
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    • 2020
  • Using webometric big data, this study examines the diversity of online information sources about the novel coronavirus causing the COVID-19 pandemic. Specifically, it focuses on some 28 countries where confirmed coronavirus cases occurred in February 2020. In the results, the online visibility of Australia, Canada, and Italy was the highest, based on their producing the most relevant information. There was a statistically significant correlation between the hit counts per country and the frequency of visiting the domains that act as information channels. Interestingly, Japan, China, and Singapore, which had a large number of confirmed cases at that time, were providing web data related to the novel coronavirus. Online sources were classified using an N-tuple helix model. The results showed that government agencies were the largest supplier of coronavirus information in cyberspace. Furthermore, the two-mode network technique revealed that media companies, university hospitals, and public healthcare centers had taken a positive attitude towards online circulation of coronavirus research and epidemic prevention information. However, semantic network analysis showed that health, school, home, and public had high centrality values. This means that people were concerned not only about personal prevention rules caused by the coronavirus outbreak, but also about response plans caused by life inconveniences and operational obstacles.

Synchronization Scheme Using Phase Offsets of PN Sequences (PN 부호의 위상오프셋을 이용한 동기 방법)

  • Song, Young-Joon;Han, Young-Yearl
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.581-584
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    • 2003
  • It is important to know phase offsets of PN (Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to make a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration far an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time of the proposed synchronization method is derived analytically, and we see that the method acquires very fast acquisition in the high SNR (Signal-to- Noise Ratio) environment.

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