An analytic model for an end-to-end acknowledgement and retransmission-based transport protocol with window flow control over a cell-based switch has been developed; acknowledgements are based on packets of multiple c...
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An analytic model for an end-to-end acknowledgement and retransmission-based transport protocol with window flow control over a cell-based switch has been developed; acknowledgements are based on packets of multiple cells. Using this model the effect of packet size, window size, and buffer size on the effective throughput or goodput of on overloaded system, where N such end-to-end sources are multiplexed onto a cell-switch, is investigated. It is shown that, for fixed window size either very small or very large packets will have better goodput. For large window and large packets, increasing the buffer size at the cell-switch will actually decrease the goodput in the overloaded case.
Hypersonic boundary-layer flow over a cold wall is considered with particular emphasis on the effect of the wall cooling on separation and stability of the hypersonic flow over a compression ramp. Numerical solutions ...
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Considers an on-line lot sizing problem with overtime. The authors develop a two-stage decision procedure for this problem. In the first stage an MLP classifies the decision situation. It is in this stage that uncerta...
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Considers an on-line lot sizing problem with overtime. The authors develop a two-stage decision procedure for this problem. In the first stage an MLP classifies the decision situation. It is in this stage that uncertainties are taken into account. The outcome of the first stage is used as input for the second stage, in which a detailed production plan is calculated. The proposed approach combines the classification and pattern recognition abilities of MLPs with traditional deterministic analysis. The authors give a brief introduction in MLPs and supervised learning and the on-line lot sizing problem is formulated. Based on results for the deterministic finite horizon problem the authors derive a two-stage strategy for the on-line lot sizing problem. Finally in they discuss some results.
The purpose of this paper is to examine the problem of controlling a linear discrete-time system subject to input saturation in order to have its output track (or reject) a family of reference (or disturbance) signals...
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The purpose of this paper is to examine the problem of controlling a linear discrete-time system subject to input saturation in order to have its output track (or reject) a family of reference (or disturbance) signals produced by some external generator. It is shown that a semi-global framework, rather than a global framework, for this problem is a natural one. Within this framework, a set of solvability conditions are given and feedback laws which solve the problem are constructed. The theory developed in this paper parallels the one we developed earlier (1996) for the continuous-time system.
We present a fairly general method for finding deterministic constructions obeying what we call k-restrictions; this yields structures of size not much larger than the probabilistic bound. The structures constructed b...
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We present a fairly general method for finding deterministic constructions obeying what we call k-restrictions; this yields structures of size not much larger than the probabilistic bound. The structures constructed by our method include (n,k)-universal sets (a collection of binary vectors of length n such that for any subset of size k of the indices, all 2/sup k/ configurations appear) and families of perfect hash functions. The near-optimal constructions of these objects imply the very efficient derandomization of algorithms in learning, of fixed-subgraph finding algorithms, and of near optimal /spl Sigma/II/spl Sigma/ threshold formulae. In addition, they derandomize the reduction showing the hardness of approximation of set cover. They also yield deterministic constructions for a local-coloring protocol, and for exhaustive testing of circuits.
We consider a system of one‐space‐dimension equations describing the combustion of a spray of droplets for a laminar counterflow. The mathematical model is derived and the existence and uniqueness of a solution is p...
We consider a system of one‐space‐dimension equations describing the combustion of a spray of droplets for a laminar counterflow. The mathematical model is derived and the existence and uniqueness of a solution is proved by using a classical fixed point method. An asymptotic behaviour in time (representing the extinction of the flame) is obtained under restrictive conditions on the involved physical parameters. The influence of the size of the mean radius of the droplets is also investigated.
Much reusable software is available for solving routine mathematical and statistical problems. Unfortunately, locating this software is often quite difficult in current distributed computing environments. The Guide to...
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Much reusable software is available for solving routine mathematical and statistical problems. Unfortunately, locating this software is often quite difficult in current distributed computing environments. The Guide to Available Mathematical Software (GAMS) virtual software repository seeks to remedy this by providing users with convenient access to thousands of software modules physically distributed among several Internet repositories, including netlib. In this paper the author will illustrate the use of GAMS, describe its implementation, and outline plans for the incorporation of expert advisory capabilities.
Based on results of computer simulations using the numerical method of lines, a simplified one-dimensional reaction-diffusion type of model, with an Arrhenius-type model for the plastic flow surface, is presented for ...
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Based on results of computer simulations using the numerical method of lines, a simplified one-dimensional reaction-diffusion type of model, with an Arrhenius-type model for the plastic flow surface, is presented for the localization of thermoelastic-plastic shear in ductile solids into an adiabatic shear band at high strain rate. This model is shown to share a number of similarities with a model of thermal reaction in a rigid solid explosive. Using small strain-rate-sensitivity asymptotics, which is analogous to high activation-energy asymptotics in the mathematical theory of combustion, it is shown there is an analogue in the mathematical theory of plasticity of the ignition problem in chemical combustion. This raises the interesting question: Does an adiabatic shear band result from a thermal explosion?
THE METHOD of small strain-rate-sensitivity asymptotics, which is the analogue of high-activation-energy asymptotics in the mathematical theory of combustion, is used to simplify a model of discontinuous plastic defor...
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THE METHOD of small strain-rate-sensitivity asymptotics, which is the analogue of high-activation-energy asymptotics in the mathematical theory of combustion, is used to simplify a model of discontinuous plastic deformation in metals during tensile loading at cryogenic temperatures. The procedure is analogous to what has been used to derive the ignition problem in combustion theory. It is shown that a degenerate Poincare-Andronov-Hopf bifurcation occurs in the simplified model as a control parameter which is proportional to the applied strain rate is increased. The bifurcation point is shown to correspond closely to the onset of ''serrations'' in the load-displacement response predicted by the original model.
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