共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper, we propose approximations to compute the steady-state performance measures of the M/GI/N+GI queue receiving Poisson arrivals with N identical servers, and general service and abandonment-time distributions. The approximations are based on scaling a single
server M/GI/1+GI queue. For problems involving deterministic and exponential abandon times distributions, we suggest a practical way to compute
the waiting time distributions and their moments using the Laplace transform of the workload density function. Our first contribution
is numerically computing the workload density function in the M/GI/1+GI queue when the abandon times follow general distributions different from the deterministic and exponential distributions.
Then we compute the waiting time distributions and their moments. Next, we scale-up the M/GI/1+GI queue giving rise to our approximations to capture the behavior of the multi-server system. We conduct extensive numerical
experiments to test the speed and performance of the approximations, which prove the accuracy of their predictions.
相似文献
2.
William D. BANKS Florian LUCA 《数学学报(英文版)》2007,23(10):1915-1918
In this note, we show that the number of composite integers n ≤ x such that φ(n)|n - 1 is at most O(x^1/2(loglog x)^1/2), thus improving earlier results by Pomerance and by Shan. 相似文献
3.
David Burns 《Inventiones Mathematicae》2007,169(3):451-499
Let K/k be a finite abelian extension of global fields. We prove that a natural equivariant leading term conjecture implies a family
of explicit congruence relations between the values at s=0 of derivatives of the Dirichlet L-functions associated to K/k. We also show that these congruences provide a universal approach to the ‘refined abelian Stark conjectures’ formulated by,
inter alia, Stark, Gross, Rubin, Popescu and Tate. We thereby obtain the first proofs of, amongst other things, the Rubin–Stark
conjecture and the ‘refined class number formulas’ of both Gross and Tate for all extensions K/k in which K is either an abelian extension of ℚ or is a function field.
Mathematics Subject Classification (1991) Primary 11G40; Secondary 11R65; 19A31; 19B28 相似文献
4.
5.
Let ƒ be a transcendental meromorphic function, a a nonzero finite complex number, and n ⩾ 2 a positive integer. Then ƒ + a(ƒ′)
n
assumes every complex value infinitely often. This answers a question of Ye for n = 2. A related normality criterion is also given.
This work was supported by the National Natural Science Foundation of China (Grant No. 10771076), the Natural Science Foundation
of Guangdong Province, China (Grant No. 07006700) and by the German-Israeli Foundation for Scientific Research and Development
(Grant No. G-809-234.6/2003) 相似文献
6.
J.C. FERRANDO S. MOLL 《数学学报(英文版)》2007,23(9):1593-1600
In this paper, we show, among other results, that if X is a [separable] locally compact space X [satisfying the first countability axiom] then the space Cc (X) has countable tightness [if and only if it has bounding tightness] if and only if it is Frechet-Urysohn, if and only if Cc (X) contains a dense (LM) subspace and if and only if X is a-compact. 相似文献
7.
8.
Guohua Wu 《Archive for Mathematical Logic》2003,42(2):201-204
We give a characterization of strongly compact cardinals in terms of Q
κ
λ. We also prove that weakly normal Q-measures on Q
κ
λ are ⊂κ-normal.
Received: 29 September 2000 / Revised version: March 2002 Published online: 5 November 2002
This project is supported by the New Zealand Marsden Fund. The author wishes to thank the referee for numerous comments and
suggestions which have been incorporated into this version of the paper. 相似文献
9.
Igor V. Dolgachev 《Proceedings of the Steklov Institute of Mathematics》2009,264(1):48-55
We show that the plane Cremona group over a field of characteristic p > 0 does not contain elements of order of power of p larger than 2. We also describe conjugacy classes of elements of order p
2.
To the memory of Vasily Iskovskikh 相似文献
10.
Tunay Bilgin 《Czechoslovak Mathematical Journal》2005,55(3):691-697
The definition of lacunary strongly convergence is extended to the definition of lacunary strong (A
σ
, p)-convergence with respect to invariant mean when A is an infinite matrix and p = (p
i
) is a strictly positive sequence. We study some properties and inclusion relations. 相似文献
11.
Thomas Vougiouklis 《数学学报(英文版)》2008,24(7):1067-1078
The hyperoperations, called theta-operations (δ), are motivated from the usual property, which the derivative has on the derivation of a product of functions. Using any map on a set, one can define δ-operations. In this paper, we continue our study on the δ-operations on groupoids, rings, fields and vector spaces or on the corresponding hyperstructures. Using δ-operations one obtains, mainly, Hwstructures, which form the largest class of the hyperstructures. For representation theory of hyperstructures, by hypermatrices, one needs special Hv-rings or Hy-fields, so these hyperstructures can be used. Moreover, we study the relation of these δ-structures with other classes of hyperstructures, especially with the Hv-structures. 相似文献
12.
Let S be a pomonoid and I a proper right ideal of S. In a previous paper, using the amalgamated coproduct A(I) of two copies of
S
S over I, we were able to solve one of the problems posed in S. Bulman-Fleming et al. (Commun. Algebra 34:1291–1317, 2006). In the present paper, we investigate further flatness properties of A(I). We also solve another problem stated in the paper cited above. Namely, we determine the condition under which Rees factor
S-posets have property (P
w
).
Research supported by nwnu-kjcxgc-03-18. 相似文献
13.
14.
P. Oswald 《Journal of Mathematical Sciences》2008,155(1):109-128
In [9], we proved numerically that spaces generated by linear combinations of some two-dimensional Haar functions exhibit
unexpectedly nice orders of approximation for solutions of the single-layer potential equation in a rectangle. This phenomenon
is closely related, on the one hand, to the properties of the approximation method of hyperbolic crosses and on the other
to the existence of a strong singularity for solutions of such boundary integral equations. In the present paper, we establish
several results on the approximation for the hyperbolic crosses and on the best N-term approximations by linear combinations of Haar functions in the H
s
-norms, −1 < s < 1/2; this provides a theoretical base for our numerical research. To the author's best knowledge, the negative smoothness
case s < 0 was not studied earlier.
__________
Translated from Sovremennaya Matematika. Fundamental'nye Napravleniya (Contemporary Mathematics. Fundamental Directions),
Vol. 25, Theory of Functions, 2007. 相似文献
15.
We derive fast recursions to compute the probability that k or more consecutive customer losses take place during a busy period of a queue, the so called k-CCL probability, for regular and oscillating M
X
/G/1/n systems. 相似文献
16.
Yaroslav Kopylov 《Archiv der Mathematik》2007,89(1):87-96
We consider some problems concerning the L
p,q
-cohomology of Riemannian manifolds. In the first part, we study the question of the normal solvability of the operator of
exterior derivation on a surface of revolution M considered as an unbounded linear operator acting from Lpk (M) into Lk+1q (M). In the second part, we prove that the first L
p,q-cohomology of the general Heisenberg group is nontrivial, provided that p < q.
Received: 17 January 2006
Supported by INTAS (Grant 03–51–3251) and the State Maintenance Program for the Leading Scientific Schools of the Russian
Federation (Grants NSh 311.2003.1, NSh 8526.2006.1). 相似文献
17.
18.
Jinjin Li 《Czechoslovak Mathematical Journal》2005,55(4):941-945
In this note we study the relation between k
R
-spaces and k-spaces and prove that a k
R
-space with a σ-hereditarily closure-preserving k-network consisting of compact subsets is a k-space, and that a k
R
-space with a point-countable k-network consisting of compact subsets need not be a k-space.
This work was supported by the NSF of China (10271056). 相似文献
19.
T. S. Kopaliani 《Ukrainian Mathematical Journal》2008,60(12):2006-2014
We point out that if the Hardy–Littlewood maximal operator is bounded on the space L
p(t)(ℝ), 1 < a ≤ p(t) ≤ b < ∞, t ∈ ℝ, then the well-known characterization of the spaces L
p
(ℝ), 1 < p < ∞, by the Littlewood–Paley theory extends to the space L
p(t)(ℝ). We show that, for n > 1 , the Littlewood–Paley operator is bounded on L
p(t) (ℝ
n
), 1 < a ≤ p(t) ≤ b < ∞, t ∈ ℝ
n
, if and only if p(t) = const.
Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 12, pp. 1709–1715, December, 2008. 相似文献
20.
In this paper, the necessary and sufficient conditions for the existence of a (gv, g, 3, λ)-difference family in Z
gv
are established. As a consequence, the existence spectrum of a cyclic (3, λ)-GDD of type g
v
without short orbits is determined.
This work was supported by National Natural Science Foundation of China (Grants Nos. 10771013, 10831002) 相似文献