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61.
Fred Raafat 《The Journal of the Operational Research Society》1991,42(1):27-37
This paper presents a complete and up-to-date survey of published inventory literature for the deteriorating (decaying) inventory models. More specifically, those papers are addressed that consider the effect of deterioration as a function of the on-hand level of inventory. The basic features, extensions and generalization of various models are discussed. A classification scheme is presented along with suggestions for future research. 相似文献
62.
63.
Fred Richman 《Indagationes Mathematicae》2002,13(2):259-267
An approach to choice-free mathematics using spreads: If constructing a point satisfying property P requires choice, replace this problem by that of constructing a nonempty set of elements satisfying P. Then construct a spread, without choice, whose elements satisfy P. The theory is developed and several examples are given. 相似文献
64.
The geometries of the dipeptides
-Pro-
-Ala,
-Pro-
-Ala and
-Pro-Gly were investigated by a grid scan ab initio calculation. The 6-31G basis set was used to estimate the effect of the alanyl side-chain on the conformation of the peptide backbone and to provide a computational basis for the interpretation of known physical-chemical properties of larger peptides that contain these dipeptides. These calculations furnish a direct quantum mechanical assessment of the energetic consequences of a methyl side-chain in the i + 2 position of a turn. The results of the calculation support the current view that the presence of a
-Ala residue in the i + 2 position favors a type II β-turn over a type I β-turn conformation, while
-Ala has the opposite effect. Total and relative energies for all the optimized conformations identified by the grid search are given and geometric parameters (bond lengths, bond angles and dihedral angles) and net atomic charges have been calculated. 相似文献
65.
Felix Weinberg Fred Carleton Dhiren Kara Agatha Xavier Derek Dunn-Rankin Matthew Rickard 《Experiments in fluids》2006,40(2):231-237
Air induction and rotation about the axis of a vertical tube is generated by an assembly of corona discharges between pinpoints
and earthed electrodes, which induces a swirling ionic wind. The mechanism is elucidated and the geometrical configuration
of the electric field lines of force is optimised by studying the deposition of charged particles on the earth electrodes,
by numerical modelling of a simplified geometry and ultimately by maximising the measured tangential velocities. Upward convective
flows of up to a litre per second are provided by an additional ionic wind pump at the base of the tube. With assemblies of
up to three layers of six points each, tangential velocities of up to 3.3 m/s (≈900 rpm) are attained at the periphery, as
recorded by small Pitot tubes. The concept, developed particularly for microgravity environments, appears suitable for adding
a substantial centrifugal contribution to the operation of electrostatic precipitators and as a basis for further progress
on electrical field-controlled burners. 相似文献
66.
We show that the value function of a singular stochastic
control problem is equal to the integral of the value function
of an associated optimal stopping problem. The connection is
proved for a general class of diffusions using the
method of viscosity solutions. 相似文献
67.
Fred van de Velde Fanny Weinbreck Marijke W. Edelman Erik van der Linden R. Hans Tromp 《Colloids and surfaces. B, Biointerfaces》2003,31(1-4):159-168
Confocal scanning laser microscopy (CSLM) has been used to study the behaviour of mixtures of proteins, gelatine, whey proteins and β-lactoglobulin, and polysaccharides, dextran, gellan gum, carrageenan, gum Arabic, and starch. CSLM proved to be a suitable technique to visualise the microstructure of these (phase separated) mixtures in two and three-dimensional images. Contrast through fluorescence is obtained either by covalent labelling (polysaccharides and proteins) or non-covalent labelling (proteins and starch). Double and triple labelling allows the visualisation of individual components in a complex mixture of biopolymers. 相似文献
68.
Bahram Alidaee Fred Glover Gary Kochenberger Haibo Wang 《European Journal of Operational Research》2007
The unconstrained quadratic binary program (UQP) is proving to be a successful modeling and solution framework for a variety of combinatorial optimization problems. Experience reported in the literature with several problem classes has demonstrated that this approach works surprisingly well in terms of solution quality and computational times, often rivaling and sometimes surpassing more traditional methods. In this paper we report on the application of UQP to the maximum edge-weighted clique problem. Computational experience is reported illustrating the attractiveness of the approach. 相似文献
69.
Thierry Cazenave Fred. B. Weissler 《NoDEA : Nonlinear Differential Equations and Applications》1998,5(3):355-365
We prove the existence of self-similar solutions of the Schr?dinger equation in with the power nonlinearity . Existence is obtained for a range of which differs from, but overlaps with, the range of powers considered in [4]. We also obtain regularity results for the self-similar
solutions constructed in [4].
Received May 16, 1997 相似文献
70.
We use surrogate analysis and constraint pairing in multidimensional knapsack problems to fix some variables to zero and to separate the rest into two groups – those that tend to be zero and those that tend to be one, in an optimal integer solution. Using an initial feasible integer solution, we generate logic cuts based on our analysis before solving the problem with branch and bound. Computational testing, including the set of problems in the OR-library and our own set of difficult problems, shows our approach helps to solve difficult problems in a reasonable amount of time and, in most cases, with a fewer number of nodes in the search tree than leading commercial software. 相似文献