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1.
A process variability control chart 总被引:1,自引:0,他引:1
In this study a Shewhart type control chart namely the V
t
chart, is proposed for improved monitoring of the process variability of a quality characteristic of interest Y. The proposed control chart is based on the ratio type estimator of the variance using a single auxiliary variable X. It is assumed that (Y, X) follows a bivariate normal distribution. The design structure of the V
t
chart is developed for Phase-I quality control and its comparison is made with those of the S
2 chart (a well-known Shewhart control chart) and the V
r
chart (a Shewhart type control chart proposed by Riaz (Comput Stat, 2008a) used for the same purpose. It is observed that
the proposed V
t
chart outperforms the S
2 and V
r
charts, in terms of discriminatory power, for detecting moderate to large shifts in the process variability. It is observed
that the performance of the V
t
chart keeps improving with an increase in |ρ
yx
| , where ρ
yx
is the correlation between Y and X. 相似文献
2.
Marco Andreatta Elena Chierici Gianluca Occhetta 《Central European Journal of Mathematics》2004,2(2):272-293
Let X be a Fano variety of dimension n, pseudoindex i
X
and Picard number ρX. A generalization of a conjecture of Mukai says that ρX(i
X
−1)≤n. We prove that the conjecture holds for a variety X of pseudoindex i
X
≥n+3/3 if X admits an unsplit covering family of rational curves; we also prove that this condition is satisfied if ρX> and either X has a fiber type extremal contraction or has not small extremal contractions. Finally we prove that the conjecture holds
if X has dimension five. 相似文献
3.
S. J. Dilworth E. Odell T. Schlumprecht A. Zsák 《Foundations of Computational Mathematics》2008,8(6):703-736
Let (e
i
) be a dictionary for a separable infinite-dimensional Banach space X. We consider the problem of approximation by linear combinations of dictionary elements with quantized coefficients drawn
usually from a ‘finite alphabet’. We investigate several approximation properties of this type and connect them to the Banach
space geometry of X. The existence of a total minimal system with one of these properties, namely the coefficient quantization property, is shown to be equivalent to X containing c
0. We also show that, for every ε>0, the unit ball of every separable infinite-dimensional Banach space X contains a dictionary (x
i
) such that the additive group generated by (x
i
) is (3+ε)−1-separated and 1/3-dense in X.
相似文献
4.
A. Krajka 《Acta Appl Math》2007,96(1-3):327-338
Let
be a probability space with a nonatomic measure P and let (S,ρ) be a separable complete metric space. Let {N
n
,n≥1} be an arbitrary sequence of positive-integer valued random variables. Let {F
k
,k≥1} be a family of probability laws and let X be some random element defined on
and taking values in (S,ρ).
In this paper we present necessary and sufficient conditions under which one can construct an array of random elements {X
n,k
,n,k≥1} defined on the same probability space and taking values in (S,ρ), and such that
, and moreover
as n→∞. Furthermore, we consider the speed of convergence
to X as n→∞.
相似文献
5.
Assume that each completely irrational noncommutative torus is realized as an inductive limit of circle algebras, and that for a completely irrational noncommutative torus Aw of rank m there are a completely irrational noncommutative torus Aρ of rank m and a positive integer d such that tr(Aw)=1/d.tr(Aρ).It is proved that the set of all C^*-algebras of sections of locally trivial C^*-algebra bundles over S^2 with fibres Aω has a group sturcture,denoted by π1^s(Aut(Aω)),which is isomorphic to Zif Ed>1 and {0} if d>1.Let Bcd be a cd-homogeneous C^*-algebra over S^2×T^2 of which no non-trivial matrix algebra can be factored out.The spherical noncommutative torus Sρ^cd is defined by twisting C^*(T2×Z^m-2) in Bcd ×C^*(Z^m-3) by a totally skew multiplier ρ on T^2×Z^m-2。It is shown that Sρ^cd×Mρ∞ is isomorphic to C(S^2)×C^*(T^2×Z^m-2,ρ)× Mcd(C)×Mρ∞ if and only if the set of prime factors of cd is a subset of the set of prime factors of p. 相似文献
6.
Shmuel Kantorovitz 《Semigroup Forum》2009,78(2):285-292
The “Volterra relation” is the commutation relation [S,V]⊂V
2, where S is a not necessarily bounded operator, V is a bounded operator leaving D(S) invariant, and [⋅,⋅] is the Lie product. When S,V are so related, and in addition iS generates a bounded C
0-group of operators and V has some general property, it is known that S+α
V (α∈ℂ) is similar to S if and only if ℜ
α=0 (cf. Theorem 11.17 in Kantorovitz, Spectral Theory of Banach Space Operators, Springer, Berlin, 1983). In particular, S−V is not similar to S. However, it is shown in this note that (without any restriction on
V
and on the group
S(⋅) generated by
iS), the perturbations (S−V)+P are similar to S for all P in the similarity sub-orbit {S(a)VS(−a);a∈ℝ} of V. When S is bounded, the above perturbations are similar to S for all P in the wider similarity sub-orbit {e
aS
Ve
−aS
;a∈ℂ}. 相似文献
7.
J. Sunklodas 《Lithuanian Mathematical Journal》2005,45(4):475-486
We derive a lower bound of L
p
norms, 1 ⩽ p ⩽ ∞, in the central limit theorem for strongly mixing random variables X
1,..., X
n
with
under the boundedness condition ℙ{|X
i
| ⩽ M} = 1 with a nonrandom constantM > 0 and condition ∑
r⩾1
r
2α(r) < ∞, where α(r) are the Rosenblatt strong mixing coefficients.
__________
Translated from Lietuvos Matematikos Rinkinys, Vol. 45, No. 4, pp. 587–602, October–December, 2005. 相似文献
8.
Xiao Hong Fu 《数学学报(英文版)》2008,24(9):1475-1482
This paper considers the isometric extension problem concerning the mapping from the unit sphere S
1(E) of the normed space E into the unit sphere S
1(l
∞(Γ)). We find a condition under which an isometry from S
1(E) into S
1(l
∞(Γ)) can be linearly and isometrically extended to the whole space. Since l
∞(Γ) is universal with respect to isometry for normed spaces, isometric extension problems on a class of normed spaces are
solved. More precisely, if E and F are two normed spaces, and if V
0: S
1(E) → S
1(F) is a surjective isometry, where c
00(Γ) ⊆ F ⊆ l
∞(Γ), then V
0 can be extended to be an isometric operator defined on the whole space.
This work is supported by Natural Science Foundation of Guangdong Province, China (Grant No. 7300614) 相似文献
9.
A new predictor-corrector algorithm is proposed for solvingP
*(κ)-matrix linear complementarity problems. If the problem is solvable, then the algorithm converges from an arbitrary positive
starting point (x
0,s
0). The computational complexity of the algorithm depends on the quality of the starting point. If the starting point is feasible
or close to being feasible, it has
-iteration complexity, whereρ
0 is the ratio of the smallest and average coordinate ofX
0
s
0. With appropriate initialization, a modified version of the algorithm terminates in O((1+κ)2(n/ρ
0)L) steps either by finding a solution or by determining that the problem has no solution in a predetermined, arbitrarily large,
region. The algorithm is quadratically convergent for problems having a strictly complementary solution. We also propose an
extension of a recent algorithm of Mizuno toP
*(κ)-matrix linear complementarity problems such that it can start from arbitrary positive points and has superlinear convergence
without a strictly complementary condition.
The work of this author was supported in part by NSF, Grant DMS 9305760 and by an Oberman fellowship from the University of
Iowa Center for Advanced Studies. 相似文献
10.
Given a positive function F on S^n which satisfies a convexity condition, we introduce the r-th anisotropic mean curvature Mr for hypersurfaces in R^n+1 which is a generalization of the usual r-th mean curvature Hr. We get integral formulas of Minkowski type for compact hypersurfaces in R^n+1. We give some new characterizations of the Wulff shape by the use of our integral formulas of Minkowski type, in case F=1 which reduces to some well-known results. 相似文献
11.
Let X be an infinite-dimensional Banach space with weight τ. By Cld
AW
(X), we denote the hyperspace of nonempty closed sets in X with the Attouch—Wets topology. By Fin
AW
(X), Comp
AW
(X) and Bdd
AW
(X), we denote the subspaces of Cld
AW
(X) consisting of finite sets, compact sets and bounded closed sets, respectively. In this paper, it is proved that
Fin
AW
(X)≈Comp
AW
(X)≈ℓ2(τ)×ℓ2
f
ℓandℓBdd
AW
(X)≈ℓ2(2τ)×ℓ2
f
where ≈ means ‘is homeomorphic to’, ℓ2(τ) is the Hilbert space with weight τ (ℓ2(ℵ0)=ℓ2 the separable Hilbert space) and
ℓ2
f
={(x
i
)
iεN
εℓ2∣x
i
=0 except for finitely many iεN}. 相似文献
12.
It is proved that ifX is a connected locally continuumwise connected coanalytic nowhere topologically complete space, then the hyperspace 2
X
of all nonempty compact subsets ofX is strongly universal in the class of all coanalytic spaces. Moreover, 2
X
is homeomorphic to Π2 ifX is a Baire space, and toQ∖Π1 ifX contains a dense absoluteG
δ-setG ⊂X such that the intersectionG ∩U is connected for any open connectedU ⊂X. (Here Π1, Π1⊂X are the standard subsets of the Hilbert cubeQ absorbing for the classes of analytic and coanalytic spaces, respectively.) Similar results are obtained for higher projective
classes.
Translated fromMatematicheskie Zametki, Vol. 62, No. 1, pp. 35–51, July, 1997.
Translated by O. V. Sipacheva 相似文献
13.
Let X
1, X
2, … be a sequence of independent identically distributed real-valued random variables, S
n
be the nth partial sum process S
n
(t) ≔ X
1 + ⋯ X
⌊tn⌋, t ∈ [0, 1], W be the standard Wiener process on [0, 1], and 2 < p < ∞. It is proved that n
−1/2
S
n
converges in law to σW as n → ∞ in p-variation norm if and only if EX
1 = 0 and σ
2 = EX
12 < ∞. The result is applied to test the stability of a regression model.
The research was partially supported by the Lithuanian State Science and Studies Foundation, grant No. T-21/07 相似文献
14.
Given a subgroup G of the symmetric group S
n
on n letters, a semigroup S of transformations of X
n
is G-normal if G
S
=G, where G
S
consists of all permutations h∈S
n
such that h
−1
fh∈S for all f∈S. A semigroup S is G-normax if it is a maximal semigroup in the set of all G-normal semigroups.
In 1996, I. Levi showed that the alternating group A
n
can not serve as the group G
S
for any semigroup of total transformations of X
n
. In 2000 and 2001, I. Levi, D.B. McAlister and R.B. McFadden described all A
n
-normal semigroups of partial transformations of X
n
. Also, in 1994, I. Levi and R.B. McFadden described all S
n
-normal semigroups.
In this paper, we show that the dihedral group D
n
may serve as the group G
S
for semigroups of transformations of X
n
. We characterize a large class of D
n
-normax semigroups and describe certain D
n
-normal semigroups. 相似文献
15.
LetG be a finite group, andS a subset ofG \ |1| withS =S
−1. We useX = Cay(G,S) to denote the Cayley graph ofG with respect toS. We callS a Cl-subset ofG, if for any isomorphism Cay(G,S) ≈ Cay(G,T) there is an α∈ Aut(G) such thatS
α =T. Assume that m is a positive integer.G is called anm-Cl-group if every subsetS ofG withS =S
−1 and | S | ≤m is Cl. In this paper we prove that the alternating groupA
5 is a 4-Cl-group, which was a conjecture posed by Li and Praeger. 相似文献
16.
Let be a field of characteristic and S
1 the unit circle. We prove that the shc-structure on a cochain algebra (A,d
A
) induces an associative product on the negative cyclic homology HC
*−
A. When the cochain algebra (A,d
A
) is the algebra of normalized cochains of the simply connected topological space X with coefficients in , then HC
*−
A is isomorphic as a graded algebra to the S
1-equivariant cohomology algebra of LX, the free loop space of X. We use the notion of shc-formality introduced in Topology 41, 85–106 (2002) to compute the S
1-equivariant cohomology algebras of the free loop space of the complex projective space when n + 1 = 0 [p] and of the even spheres S
2n
when p = 2.
相似文献
17.
Sebastian Król 《Semigroup Forum》2009,79(2):369-376
We show that every contractive C
0-semigroup on a separable, infinite-dimensional Hilbert space X can be approximated by unitary C
0-groups in the weak operator topology uniformly on compact subsets of ℝ+. As a consequence we get a new characterization of a bounded H
∞-calculus for the negatives of generators of bounded holomorphic semigroups. Applications of our results to the study of a
topological structure of the set of (almost) weakly stable contractive C
0-semigroups on X are also discussed.
The author was partially supported by the Marie Curie “Transfer of Knowledge” programme, project “TODEQ”, and by a MNiSzW
grant Nr. N201384834. 相似文献
18.
J. C. Gómez-Larrañaga F. González-Acuña Wolfgang Heil 《Mathematische Zeitschrift》2008,259(2):419-432
A closed topological n-manifold M
n
is of S
1-category 2 if it can be covered by two open subsets W
1,W
2 such that the inclusions W
i
→ M
n
factor homotopically through maps W
i
→ S
1 → M
n
. We show that the fundamental group of such an n-manifold is a cyclic group or a free product of two cyclic groups with nontrivial amalgamation. In particular, if n = 3, the fundamental group is cyclic.
相似文献
19.
Let X,X 1,X 2,… be a sequence of non-degenerate i.i.d. random variables with mean zero. The best possible weighted approximations are investigated in D[0, 1] for the partial sum processes {S [nt], 0 ≦ t ≦ 1} where S n = Σ j=1 n X j , under the assumption that X belongs to the domain of attraction of the normal law. The conclusions then are used to establish similar results for the sequence of self-normalized partial sum processes {S [nt]=V n , 0 ≦ t ≦ 1}, where V n 2 = Σ j=1 n X j 2 . L p approximations of self-normalized partial sum processes are also discussed. 相似文献
20.
Ourania Chryssaphinou Eutichia Vaggelatou 《Annals of the Institute of Statistical Mathematics》2002,54(2):411-424
We consider a sequence X
1, ..., X
n of r.v.'s generated by a stationary Markov chain with state space A = {0, 1, ..., r}, r 1. We study the overlapping appearances of runs of k
i consecutive i's, for all i = 1, ..., r, in the sequence X
1,..., X
n. We prove that the number of overlapping appearances of the above multiple runs can be approximated by a Compound Poisson r.v. with compounding distribution a mixture of geometric distributions. As an application of the previous result, we introduce a specific Multiple-failure mode reliability system with Markov dependent components, and provide lower and upper bounds for the reliability of the system. 相似文献