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231.
We give an almost complete classification of ergodicity and transience conditions for a general multi-queue system with the
following features: arrivals form Poisson streams and there are various routing schemes for allocating arrivals to queues;
the servers can be configured in a variety of ways; completed jobs can feed back into the system; the exponential service
times and feedback probabilities depend upon the configuration of the servers (this model includes some types of multi-class
queueing system); switching between service regimes is instantaneous. Several different levels of control of the service regimes
are considered. Our results for the N-queue system require randomisation of service configurations but we have studied the two queue system in situations where
there is less control. We use the semi-martingale methods described in Fayolle, Malyshev and Menshikov [3] and our results
generalise Kurkova [8] and complement Foley and McDonald [4] and [5].
AMS 2000 subject classification: Primary: 90B22; Secondary: 60J10 90B15 相似文献
232.
233.
234.
V. Shatokhin T. Wellens C. A. Müller A. Buchleitner 《The European physical journal. Special topics》2007,151(1):51-57
We survey recent progress achieved in understanding the
impact of inelastic processes on coherent backscattering of light
from cold atoms that are saturated by a powerful laser field. 相似文献
235.
236.
Monika Schuster Robert Inführ Claudia Turecek Jürgen Stampfl Franz Varga Robert Liska 《Monatshefte für Chemie / Chemical Monthly》2006,4(4):843-853
To substitute cross-linked photopolymers in rapid prototyping of mold materials and therefore extend the range of materials
which can be casted, organo-soluble photopolymers were developed. Branched bisalkylacrylamides were suitable as base component
for such formulations, due to their high reactivity, good mechanical properties, and excellent solubility of the formed polymers.
These molding materials were used to prepare cellular biocompatible materials which could be used as bone replacement materials.
Biocompatible crosslinkers based on methacrylates from hydrolyzed gelatine or lactic acid ethyleneglycol blockcopolymers and
commercially available reactive diluents are the base components of such a formulation. Biocompatibility was investigated
by osteoblast-like cells. Cellular biocompatible parts were obtained by thermal polymerization in soluble mould materials
prepared by 3D-photoshaping. 相似文献
237.
Uwe Bandelow Mindaugas Radziunas Andrei Vladimirov Bernd Hüttl Ronald Kaiser 《Optical and Quantum Electronics》2006,38(4-6):495-512
We study both theoretically and experimentally typical operation regimes of 40 GHz monolithic mode-locked lasers. The underlying
Traveling Wave Equation model reveals quantitative agreement for characteristics of the fundamental mode-locking as pulse
width and repetition frequency tuning, as well as qualitative agreement with the experiments for other dynamic regimes. Especially
the appearance of stable harmonic mode-locking at 80 GHz has been predicted theoretically and confirmed by measurements. Furthermore,
we derive and apply a simplified Delay-Differential-Equation model which guides us to a qualitative analysis of bifurcations
responsible for the appearance and the breakup of different mode-locking regimes. Higher harmonics of mode-locking are predicted
by this model as well. 相似文献
238.
In this article, local optimality in multiobjective combinatorial optimization is used as a baseline for the design and analysis
of two iterative improvement algorithms. Both algorithms search in a neighborhood that is defined on a collection of sets
of feasible solutions and their acceptance criterion is based on outperformance relations. Proofs of the soundness and completeness
of these algorithms are given. 相似文献
239.
I. N. Koprinarov U. Müller-Jahreis P. Thiele 《Applied Physics A: Materials Science & Processing》1996,62(6):565-570
The crystalline-amorphous transition in GaAs induced by Ar ions (energy 1–3 keV) has been investigated using single-wavelength ellipsometry. The experiments have been performed in-situ at room temperature. Ion damage straggling, amorphization threshold and critical energy density have been derived by means of a simple analytical model for the growth of the amorphous layer. This model is discussed and the corresponding calculations are found to be in satisfactory agreement with experimental data. 相似文献
240.
H. Günther M. Foerste M. Kunze G. zu Putlitz U. von Stein 《Zeitschrift für Physik B Condensed Matter》1996,100(4):613-617
We review the previous conclusion [J.Y. Ryu, Y.C. Chung and S.D. Choi, Phys. Rev. B 32, 7769 (1984)] that the trace property Tr(ABC) = Tr(CAB) leads to two different cyclotron transition absorption formulae in the electron-phonon systems in the lowest order approximation. The pictorial expression and the calculated linewidths in Ge and Si show that the socalled EWC scheme is more seeming than the socalled MWC scheme. The difference is expected to disappear if we take into account all the higher order perturbation terms or start with the many body formalism in the complete scheme. 相似文献