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991.
992.
Messoud Efendiev 《Journal of Mathematical Analysis and Applications》2009,358(1):136-147
In this paper we continue systematic study of the dimension estimate of the global attractors for the chemotaxis-growth system and its finite-element approximations. Utilizing a conservative upwind finite-element scheme we managed significantly to improve dimension estimates with respect to the chemotactic parameter. 相似文献
993.
Yaroslav D. Sergeyev 《Computational Optimization and Applications》2006,34(2):229-248
This paper proposes a new algorithm for solving constrained global optimization problems where both the objective function
and constraints are one-dimensional non-differentiable multiextremal Lipschitz functions. Multiextremal constraints can lead
to complex feasible regions being collections of isolated points and intervals having positive lengths. The case is considered
where the order the constraints are evaluated is fixed by the nature of the problem and a constraint i is defined only over the set where the constraint i−1 is satisfied. The objective function is defined only over the set where all the constraints are satisfied. In contrast
to traditional approaches, the new algorithm does not use any additional parameter or variable. All the constraints are not
evaluated during every iteration of the algorithm providing a significant acceleration of the search. The new algorithm either
finds lower and upper bounds for the global optimum or establishes that the problem is infeasible. Convergence properties
and numerical experiments showing a nice performance of the new method in comparison with the penalty approach are given.
This research was supported by the following grants: FIRB RBNE01WBBB, FIRB RBAU01JYPN, and RFBR 04-01-00455-a. The author
thanks Prof. D. Grimaldi for proposing the application discussed in the paper.
An erratum to this article is available at . 相似文献
994.
The use of integrated circuits in high-performance computing, telecommunications, and consumer electronics has been growing
at a very fast pace. The level of integration as measured by the number of logic gates in a chip has been steadily rising
due to the rapid progress in processing and interconnect technology. The interconnect delay in VLSI circuits has become a
critical determiner of circuit performance. As a result, circuit layout is starting to play a more important role in today’s
chip designs. Global routing is one of the key sub-problems of circuit layout which involves finding an approximate path for
the wires connecting the elements of the circuit without violating resource constraints. In this paper, several integer programming
(ILP) based global routing models are fully investigated and explored. The resulting ILP problem is relaxed and solved as
a linear programming (LP) problem followed by a rounding heuristic to obtain an integer solution. Experimental results obtained
show that the proposed combined WVEM (wirelength, via, edge capacity) model can optimize several global routing objectives
simultaneously and effectively. In addition, several hierarchical methods are combined with the proposed flat ILP based global
router to reduce the CPU time by about 66% on average for edge capacity model (ECM). 相似文献
995.
Global classical solutions near the relativistic Maxwellian are constructed for the relativistic Boltzmann equation in both a periodic box and the whole space. For both cases, we are able to get the non‐negativity of the global solution under less restriction than in (Publ. Res. Inst. Math. Sci. 1993; 29 :301–347) on the scattering kernel. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
996.
研究了在分子晶体中的一类广义非线性Schroedinger方程组的初边值问题.应用先验估计的方法,得到了整体解的存在性. 相似文献
997.
998.
本文考虑了一类食饵具有流行病和阶段结构的脉冲时滞捕食模型.利用脉冲时滞微分方程的相关理论和方法,获得易感害虫根除周期解全局吸引的充分条件以及当脉冲周期在一定范围内时,天敌与易感害虫可以共存且易感害虫的密度可以控制在经济危害水平E(EIL)之下.我们的结论为现实的害虫管理提供了可靠的策略依据. 相似文献
999.
Investigations of gas and particle dynamics in first generation needle-free drug delivery devices 总被引:1,自引:0,他引:1
Abstract. Transdermal powdered drug delivery involves the propulsion of solid drug particles into the skin by means of high-speed gas-particle
flow. The fluid dynamics of this technology have been investigated in devices consisting of a convergent-divergent nozzle
located downstream of a bursting membrane, which serves both to initiate gas flow (functioning as the diaphragm of a shock
tube) and to retain the drug particles before actuation. Pressure surveys of flow in devices with contoured nozzles of relatively
low exit-to-throat area ratio and a conical nozzle of higher area ratio have indicated a starting process of approximately
200 s typical duration, followed by a quasi-steady supersonic flow. The velocity of drug particles exiting the contoured nozzles
was measured at up to 1050 m/s, indicating that particle acceleration took place primarily in the quasi-steady flow. In the
conical nozzle, which had larger exit area ratio, the quasi-steady nozzle flow was found to be overexpanded, resulting in
a shock system within the nozzle. Particles were typically delivered by these nozzles at 400 m/s, suggesting that the starting
process and the quasi-steady shock processed flow are both responsible for acceleration of the particle payload. The larger
exit area of the conical nozzle tested enables drug delivery over a larger target disc, which may be advantageous.
Received 12 March 2000 / Accepted 8 June 2000 相似文献
1000.
In this paper, we combine the nonmonotone and adaptive techniques with trust region method for unconstrained minimization problems. We set a new ratio of the actual descent and predicted descent. Then, instead of the monotone sequence, the nonmonotone sequence of function values are employed. With the adaptive technique, the radius of trust region △k can be adjusted automatically to improve the efficiency of trust region methods. By means of the Bunch-Parlett factorization, we construct a method with indefinite dogleg path for solving the trust region subproblem which can handle the indefinite approximate Hessian Bk. The convergence properties of the algorithm are established. Finally, detailed numerical results are reported to show that our algorithm is efficient. 相似文献