• Title/Summary/Keyword: ${\sigma}$-derivation

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ORE EXTENSIONS OVER σ-RIGID RINGS

  • Han, Juncheol;Lee, Yang;Sim, Hyo-Seob
    • East Asian mathematical journal
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    • v.38 no.1
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    • pp.1-12
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    • 2022
  • Let R be a ring with an endomorphism σ and a σ-derivation δ. R is called (σ, δ)-Baer (resp. (σ, δ)-quasi-Baer, (σ, δ)-p.q.-Baer, (σ, δ)-p.p.) if the right annihilator of every right (σ, δ)-set (resp., (σ, δ)-ideal, principal (σ, δ)-ideal, (σ, δ)-element) of R is generated by an idempotent of R. In this paper, for a given Ore extension A = R[x; σ, δ] of R, the following properties are investigated: If R is a σ-rigid ring in which σ and δ commute, then (1) R is (σ, δ)-Baer if and only if R is (σ, δ)-quasi-Baer if and only if A is (${\bar{\sigma}},\;{\bar{\delta}}$)-Baer if and only if A is (${\bar{\sigma}},\;{\bar{\delta}}$)-quasi-Baer; (2) R is (σ, δ)-p.p. if and only if R is (σ, δ)-p.q.-Baer if and only if A is (${\bar{\sigma}},\;{\bar{\delta}}$)-p.p. if and only if A is (${\bar{\sigma}},\;{\bar{\delta}}$)-p.q.-Baer.

SEMICOMMUTATIVE PROPERTY ON NILPOTENT PRODUCTS

  • Kim, Nam Kyun;Kwak, Tai Keun;Lee, Yang
    • Journal of the Korean Mathematical Society
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    • v.51 no.6
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    • pp.1251-1267
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    • 2014
  • The semicommutative property of rings was introduced initially by Bell, and has done important roles in noncommutative ring theory. This concept was generalized to one of nil-semicommutative by Chen. We first study some basic properties of nil-semicommutative rings. We next investigate the structure of Ore extensions when upper nilradicals are ${\sigma}$-rigid ${\delta}$-ideals, examining the nil-semicommutative ring property of Ore extensions and skew power series rings, where ${\sigma}$ is a ring endomorphism and ${\delta}$ is a ${\sigma}$-derivation.

ON A LIE RING OF GENERALIZED INNER DERIVATIONS

  • Aydin, Neset;Turkmen, Selin
    • Communications of the Korean Mathematical Society
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    • v.32 no.4
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    • pp.827-833
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    • 2017
  • In this paper, we define a set including of all $f_a$ with $a{\in}R$ generalized derivations of R and is denoted by $f_R$. It is proved that (i) the mapping $g:L(R){\rightarrow}f_R$ given by g (a) = f-a for all $a{\in}R$ is a Lie epimorphism with kernel $N_{{\sigma},{\tau}}$ ; (ii) if R is a semiprime ring and ${\sigma}$ is an epimorphism of R, the mapping $h:f_R{\rightarrow}I(R)$ given by $h(f_a)=i_{{\sigma}(-a)}$ is a Lie epimorphism with kernel $l(f_R)$ ; (iii) if $f_R$ is a prime Lie ring and A, B are Lie ideals of R, then $[f_A,f_B]=(0)$ implies that either $f_A=(0)$ or $f_B=(0)$.

Derivation of the Critical Minimum Values of the Multiple Correlation Coefficient for Augmenting Hydrologic Samples (수문자료 확충을 위한 다중상관계수의 한계최소치 유도)

  • 허준행
    • Water for future
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    • v.27 no.1
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    • pp.133-140
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    • 1994
  • The augmenting hydrologic data using a correlation procedue has been used to improve the estimates of the mean and variance at the site of interest with short record when one or more nearby sites with longer records are available. The variance of the unbiased maximum likelihood estimator of ${{\sigma}_v}^2$ derived by Moran based on the multivariate normal distribution is modified into the form of Matalas and jacobs for the bivariate normal distribution to get the critical minimum values of the multiple correlation coefficient which give the improvement for estimation the variance at the site of interest. Those values are tabulated for various lengths of records and the number of sites.

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GENERALIZED COHOMOLOGY GROUP OF TRIANGULAR BANACH ALGEBRAS OF ORDER THREE

  • Motlagh, Abolfazl Niazi;Bodaghi, Abasalt;Tanha, Somaye Grailoo
    • Honam Mathematical Journal
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    • v.42 no.1
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    • pp.105-121
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    • 2020
  • The main result of this article is to factorize the first (σ, τ)-cohomology group of triangular Banach algebra 𝓣 of order three with coefficients in 𝓣 -bimodule 𝓧 to the first (σ, τ)-cohomology groups of Banach algbras 𝓐, 𝓑 and 𝓒, where σ, τ are continuous homomorphisms on 𝓣. As a direct consequence, we find necessary and sufficient conditions for 𝓣 to be (σ, τ)-weakly amenable.

Charts for estimating rock mass shear strength parameters

  • Wan, Ling;Wei, Zuoan;Shen, Jiayi
    • Geomechanics and Engineering
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    • v.10 no.3
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    • pp.257-267
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    • 2016
  • Charts are used extensively in slope practical application to meet the need of quick assessment of rock slope design. However, Charts for estimating the shear strength of the rock mass of a slope are considerably limited. In this paper, based on the Hoek-Brown (HB) criterion which is widely used in rock slope engineering, we present charts which can be used to estimate the Mohr-Coulomb (MC) parameters angle of friction ${\phi}$ and cohesion c for given slopes. In order to present the proposed charts, we firstly present the derivation of the theoretical relationships between the MC parameters and ${\sigma}_{ci}/({\gamma}H)$ which is termed the strength ratio (SR). It is found that the values of $c/{\sigma}_{ci}$ and ${\phi}$ of a slope depend only on the magnitude of SR, regardless of the magnitude of the individual parameters ${\sigma}_{ci}$(uniaxial compressive strength), ${\gamma}$(unit weight) and H (slope height). Based on the relationships between the MC parameters and SR, charts are plotted to show the relations between the MC parameters and HB parameters. Using the proposed charts can make a rapid estimation of shear strength of rock masses directly from the HB parameters, slope geometry and rock mass properties for a given slope.

Review and Derivation of Sample Size Determination for Hypothesis Testing and Interval Estimation (가설검정 및 구간추정에서 샘플크기 결정규칙의 고찰 및 유도)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2012.11a
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    • pp.461-471
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    • 2012
  • Most useful statistical techniques in six sigma DMAIC are hypothesis testing and interval estimation. So this paper reviews and derives sample size formula by considering significance level, power of detectability and effect difference. The quality practioners can effectively interpret the practical and statistical significance with the rational sample sizing.

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Derivation and verification of influence function on parameter δ proposed by Ghosh and Kim (Ghosh와 Kim 모수 δ의 영향함수 유도 및 확인)

  • Kim, Minjeong;Kim, Honggie
    • The Korean Journal of Applied Statistics
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    • v.30 no.4
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    • pp.529-538
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    • 2017
  • The Ghosh and Kim zero-altered distribution model is used to analyze count data that have too many or too few zeros. The dispersion type parameter ${\delta}$ in the zero-altered distribution model consists of mean, variance and zero probability and has two forms depending on the relation between ${\mu}$ and ${\sigma}^2$. We derived the influence function on ${\delta}$ when ${\sigma}^2{\geq}{\mu}$. To show the validity of the influence function, we used the Census data on the number of births of married women in Korea to compare the estimated changes in ${\delta}$ using this function with those obtained using the direct deletion method. The result proved that the obtained influence function is very accurate in estimating changes in ${\delta}$ when an observation is deleted.

Derivation and Analysis of Dimensionless Parameters Dominating the Dehumidification Characteristics of a Desiccant Rotor (제습로터의 운전특성을 재배하는 무차원 인자의 도출과 해석)

  • Lee Gilbong;Kim Min Soo;Lee Dae-Young
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.7
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    • pp.611-619
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    • 2005
  • In a previous work of the authors, the heat and mass transfer in a desiccant rotor was analyzed theoretically through linearization assumptions and four dimensionless parameter groups dominating the dehumidification process were arranged. In this work is verified whether the four dimensionless parameters also play the dominant roles in more realistic situations where the nonlinear factors affect the heat and mass transfer. The results show that the dehumidification characteristics are closely similar to each other as long as the four dimensionless parameters have the same set of values while the rotor configurations and/or the operation conditions are different from each other. The four dimensionless parameters are $\Psi,\;\chi,\;\sigma$ and N, where $\Psi$ implies the average gradient of relative humidity lines in the psychrometric chart, $\chi$ the heat capacity of the rotor and $\sigma$ the sorption capacity of the rotor, and N implies the number of transfer unit.

Derivation of design equations for various incremental delta sigma analog to digital converters (다양한 증분형 아날로그 디지털 변환기의 설계 방정식 유도)

  • Jung, Youngho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.11
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    • pp.1619-1626
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    • 2021
  • Unlike traditional delta-sigma analog-to-digital converters, incremental analog-to-digital converters enable 1:1 mapping of input and output through a reset operation, which can be used very easily for multiplexing. Incremental analog-to-digital converters also allow for simpler digital filter designs compared to traditional delta-sigma converters. Therefore, starting with analysis in the time domain of the delayed integrator and non-delayed integrator, which are the basic blocks of analog-to-digital converter design, the design equations of a second-order input feed-forward, extended counting, 2+1 MASH (Multi-stAge-noise-SHaping), 2+2 MASH incremental analog-to-digital converter are derived in this paper. This allows not only prediction of the performance of the incremental analog-to-digital converter before design, but also the design of a digital filter suitable for each analog-to-digital converter. In addition, extended counting and MASH design techniques were proposed to improve the accuracy of analog-to-digital converters.