• 제목/요약/키워드: $\sigma^{54}$

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

  • 성수경;윤태홍;변재현
    • 품질경영학회지
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    • 제36권3호
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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.

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

  • 유지수;김주영;김혜정
    • 품질경영학회지
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    • 제37권3호
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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
    • 대한수학회지
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    • 제54권2호
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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.

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

  • 고재귀;이정훈
    • 한국자기학회지
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    • 제11권5호
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    • pp.217-221
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    • 2001
  • Fe$^{2+}$와 Fe$^{3+}$ 의 혼합 수용액에 공침 보조 용액 3N-NaOH를 첨가해 공침 반응 시켜 Magnetite를 제조하였다. Magnetite의 제조에 앞서 첨가되는 Fe$^{2+}$이온과 Fe$^{3+}$ 이온의 비를 변화시키면서 Magnetite의 자기적 특성 변화를 조사하였다. 또한 Magnetite의 제조 온도의 변화를 통해 Magnetite의 자기적 특성 변화를 살펴보았고, 이렇게 제조된 Magnetite의 자성유체로서의 가능성을 알아보기 위해 X-ray 회절을 통해 결정성을 살펴보았다. 그 결과 Magnetite분말의 합성에서 Fe$^{2+}$와 Fe$^{3+}$ 의 비가 0.46 : 0.54일 때 Magnetite의 자기적 특성값 $\sigma$$_{s}$,는 60.8 emu/g이었고, 같은 조건에서 합성 온도를 80 $^{\circ}C$로 30분간 유지 시켰을 때의 $\sigma$$_{s}$ 값은 63.51 emu/g으로 교반 온도가 높을수록 자기적 특성값이 좋아지는 것을 알 수 있었다.다.

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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.
    • 천문학회보
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    • 제39권1호
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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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2차 Space Dithered Sigma-Delta Modulation 기반의 Random PWM 스위칭 기법을 이용한 강압형 DC-DC 컨버터의 성능 개선 (Performance Improvement of a Buck Converter using a End-order Space Dithered Sigma-Delta Modulation based Random PWM Switching Scheme)

  • 김서형;주성탁;정해광;이교범;정규범
    • 전력전자학회논문지
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    • 제14권1호
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    • pp.54-61
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    • 2009
  • 본 논문에서는 강압형 DC-DC 컨버터의 성능 개선을 위한 스위칭 기법인 2차 SDSDM (Space Dithered Sigma Delta Modulation)방식을 제안한다. PWM (Pulse Width Modulation) 방식은 일정 스위칭 주파수 대역에서의 고조파로 인해 소음, 전자파 장애, 스위칭 손실 등을 유발한다. 이러한 문제를 해결하기 위한 DSDM 방식의 일종인 1차 SDSDM은 랜덤 디더(Random Dither) 발생기가 1차 SDM의 양자화기(quatizer) 입력단에 위치하여 스위칭 주파수가 분산된다. 강압형 DC/DC 컨버터에 제안하는 2차 SDSDM의 방식을 적용한 실험 결과를 통해 타당성을 검증한다.

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.

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

  • Kamalov, Firuz
    • 대한수학회보
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    • 제54권2호
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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 $\widehat{A{\rtimes}_{\sigma}G}$.