• Title/Summary/Keyword: Sigma 54

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Six Sigma Performance Evaluation System and a Case Study for Order-Based Industry (수주산업의 6시스마 성과 평가체계와 사례)

  • Sung, Su-Gyeong;Yun, Tae-Hong;Byun, Jai-Hyun
    • Journal of Korean Society for Quality Management
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    • v.36 no.3
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    • pp.45-54
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    • 2008
  • For successful accomplishment of six sigma innovation, one of the most important factor is performance evaluation and proper compensation. Six sigma project teams are well motivated to perform the projects only when their activities are properly evaluated and reasonable compensations are secured. In this paper, a systematic evaluation system of financial effect of six sigma projects is presented for order-based aerospace industry.

An Empirical Study on Associations among Learning Organization, Suggestion Activities, and Six Sigma Performance (학습조직, 제안활동, 6시그마 성과 간 연관관계에 관한 실증 연구)

  • Yu, Ji-Soo;Kim, Ju-Young;Kim, Hye-Jeong
    • Journal of Korean Society for Quality Management
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    • v.37 no.3
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    • pp.54-64
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    • 2009
  • This study conducts an empirical analysis of how the suggestion activity, most widely used in quality control activities, interacts with the dimensions of learning organizations. The study also attempts to analyze the results of Six Sigma based on sub-dimensions of learning organizations, which are infrastructure, culture and system. In order for learning and innovation to take place in implementing a Six Sigma program, the organizational infrastructure and culture are created and sustained and then, a learning organization system would become effective. In this study, a empirical model is used to demonstrate such an association. The sample consists of 134 organizations who have implemented a Six Sigma program for more than three years. Using the version 16.0 of AMOS for structural equation modeling, the study estimates the structural equation model that has a Six Sigma organization's infrastructure, culture and system as independent constructs, the suggestion system as a mediator, and the performance of Six Sigma projects as a dependent construct.

ZERO-DENSITY ESTIMATES FOR EPSTEIN ZETA FUNCTIONS OF CLASS NUMBERS 2 OR 3

  • Lee, Yoonbok
    • Journal of the Korean Mathematical Society
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    • v.54 no.2
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    • pp.479-491
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    • 2017
  • We investigate the zeros of Epstein zeta functions associated with positive definite quadratic forms with rational coefficients in the vertical strip ${\sigma}_1$ < ${\Re}s$ < ${\sigma}_2$, where 1/2 < ${\sigma}_1$ < ${\sigma}_2$ < 1. When the class number h of the quadratic form is bigger than 1, Voronin gave a lower bound and Lee gave an asymptotic formula for the number of zeros. Recently Gonek and Lee improved their results by providing a new upper bound for the error term when h > 3. In this paper, we consider the cases h = 2, 3 and provide an upper bound for the error term, smaller than the one for the case h > 3.

The Study of Physical Properties of Magnetite Fluids Prepared by Coprecipitation Method (공침법에 의해서 제조된 자성유체의 자기적 특성 변화 연구)

  • 고재귀;이정훈
    • Journal of the Korean Magnetics Society
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    • v.11 no.5
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    • pp.217-221
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    • 2001
  • We made magnetite which was prepared with mixed liquids of Fe$\^$2+/and Fe$\^$3+/ added to the 3N-NaOH by coprecipitation reaction. Ahead of making magnetite, we investigated variation of physical properties for changing Fe$\^$2+/ : Fe$\^$3+/. Through the variation of the process temperature, we examined physical properties of magnetite. Also, to examine possibility of magnetic fluids, from magnetite manufactured in this way, we examined the crystal structure by X-ray diffraction pattern. The saturated magnetization $\sigma$$\_$s/, value has 60.8 emu/g, when Fe$\^$2+/ to Fe$\^$3+/ ratio is 0.46 : 0.54 in the synthetic magnetite. Keeping the condition, when the synthetic temperature is kept at 80$\^{C}$ for 30 minutes, we get $\sigma$$\_$s/, value 63.51 emu/g. It shows that $\sigma$$\_$s/, value is bigger as the synthetic temperature is higher.

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System Design of SIGMA(KHUSAT-3) CubeSat Mission

  • Lee, Seongwhan;Lee, Junkyu;Kum, Kanghoon;Lee, Hyojeong;Seo, Junwon;Shin, Youra;Jeong, Seonyoung;Shin, Jehyuck;Cheon, Junghoon;Kim, Hanjun;Jin, Ho;Nam, Uk-Won;Kim, Sunghwan;Lee, Regina;Lessard, Marc R.
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.54.1-54.1
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    • 2014
  • Kyung Hee University has been developing a CubeSat for the space science mission called SIGMA (Scientific cubesat with Instrument for Global Magnetic field and rAdiation), which includes TEPC (Tissue Equivalent Proportional Counter) and a magnetometer. SIGMA has a 3-unit CubeSat, and the weight is about 3.2 kg. The main payload is TEPC which can measure the Linear Energy Transfer (LET) spectrum and calculate the equivalent dose for the complicated radiation field in the space. The magnetometer is a secondary payload using a miniaturized fluxgate magnetometer. We expect it to have a 1 nT resolution in the dynamic range of ${\pm}65535$ nT. An Attitude Control System (ACS) spins the SIGMA spacecraft 4 rpm with the spin axis perpendicular to the ecliptic plane. Full duplex communication is consists of VHF uplink and S-band and UHF downlink. In this paper, we introduce the system design and the scientific purpose of the SIGMA CubeSat mission.

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Performance Improvement of a Buck Converter using a End-order Space Dithered Sigma-Delta Modulation based Random PWM Switching Scheme (2차 Space Dithered Sigma-Delta Modulation 기반의 Random PWM 스위칭 기법을 이용한 강압형 DC-DC 컨버터의 성능 개선)

  • Kim, Seo-Hyeong;Ju, Seong-Tak;Jung, Hea-Gwang;Lee, Kyo-Beum;Jung, Gyu-Bum
    • The Transactions of the Korean Institute of Power Electronics
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    • v.14 no.1
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    • pp.54-61
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    • 2009
  • This paper proposes the 2nd-order SDSDM (Space Dithered Sigma-Delta Modulation) for performance improvement of a buck converter. The PWM (Pulse Width Modulation) has a drawback in that power spectrum tends to be concentrated around the switching frequency. The resulting harmonic spikes cause a EMI(Electromagnetic Interference) and switching loss in semiconductor, etc. The 1st-order SDSDM scheme is a kind of DSDM for reducing these harmonic spikes. In this scheme, a switching frequency is spread through random dither generator placed on input part. In experimental result, the proposed 2nd-order SDSDM is confirmed by applying to a buck converter.

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.

ON THE TOPOLOGY OF THE DUAL SPACE OF CROSSED PRODUCT C*-ALGEBRAS WITH FINITE GROUPS

  • Kamalov, Firuz
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.2
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    • pp.391-397
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    • 2017
  • In this note we extend our previous result about the structure of the dual of a crossed product $C^*$-algebra $A{\rtimes}_{\sigma}G$, when G is a finite group. We consider the space $\tilde{\Gamma}$ which consists of pairs of irreducible representations of A and irreducible projective representations of subgroups of G. Our goal is to endow $\tilde{\Gamma}$ with a topology so that the orbit space e $G{\backslash}{\tilde{\Gamma}}$ is homeomorphic to the dual of $A{\rtimes}_{\sigma}G$. In particular, we will show that if $\widehat{A}$ is Hausdorff then $G{\backslash}{\tilde{\Gamma}}$ is homeomorphic to $\widehat{A{\rtimes}_{\sigma}G}$.