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1.
The design of the underlying supply chain network can have a tremendous impact on the profitability, manageability, and level of risk of a global supply chain. Taxes, duties, and tariffs vary from country to country as well as trading bloc to trading bloc and can consume as much as 10% of the revenues of certain products. In the highly regulated business environment of agricultural chemicals, the country of origin of an active ingredient can determine where the final product can be marketed and the amount of taxes and duties applied to the product, making it necessary to trace all batches of product through many layers of the supply chain to their sources. This article presents a mixed integer linear programming model in use at Dow AgroSciences LLC that simultaneously optimizes the network design underlying global supply chains and the monthly production and shipping schedules for maximum profitability. This work contributes to the supply chain design literature by demonstrating a novel method of tracing products to their source for inventory valuation, taxation, and duty computation in a production environment where the products change into other products as they pass through nodes in the network. It also demonstrates an iterative scheme for determining unit fixed costs for fixed cost allocation for the same purposes. Finally, it provides a case study of a supply chain design initiative in a global enterprise. 相似文献
2.
Rade T. Živaljević 《Discrete and Computational Geometry》2009,41(1):135-161
This paper lays the foundation for a theory of combinatorial groupoids that allows us to use concepts like “holonomy”, “parallel transport”, “bundles”, “combinatorial curvature”, etc. in the context
of simplicial (polyhedral) complexes, posets, graphs, polytopes and other combinatorial objects. We introduce a new, holonomy-type
invariant for cubical complexes, leading to a combinatorial “Theorema Egregium” for cubical complexes that are non-embeddable
into cubical lattices. Parallel transport of Hom-complexes and maps is used as a tool to extend Babson–Kozlov–Lovász graph coloring results to more general statements about
nondegenerate maps (colorings) of simplicial complexes and graphs.
The author was supported by grants 144014 and 144026 of the Serbian Ministry of Science and Technology. 相似文献
3.
We consider an operator of Bernstein for symmetric functions and give an explicit formula for its action on an arbitrary Schur
function. This formula is given in a remarkably simple form when written in terms of some notation based on the code of a
partition. As an application, we give a new and very simple proof of a classical result for the KP hierarchy, which involves
the Plücker relations for Schur function coefficients in a τ-function for the hierarchy. This proof is especially compact because we are able to restate the Plücker relations in a form
that is symmetrical in terms of partition code notation. 相似文献
4.
Piero D’Ancona Vittoria Pierfelice Fulvio Ricci 《Journal of Fourier Analysis and Applications》2010,16(2):294-310
The dispersive properties of the wave equation u
tt
+Au=0 are considered, where A is either the Hermite operator −Δ+|x|2 or the twisted Laplacian −(∇
x
−iy)2/2−(∇
y
+ix)2/2. In both cases we prove optimal L
1−L
∞ dispersive estimates. More generally, we give some partial results concerning the flows exp (itL
ν
) associated to fractional powers of the twisted Laplacian for 0<ν<1. 相似文献
5.
Nail H. Ibragimov 《Acta Appl Math》2009,105(2):157-187
The evolution equations of Maxwell’s equations has a Lagrangian written in terms of the electric E and magnetic H fields, but admit neither Lorentz nor conformal transformations. The additional equations ∇⋅E=0, ∇⋅H=0 guarantee the Lorentz and conformal invariance, but the resulting system is overdetermined, and hence does not have a Lagrangian.
The aim of the present paper is to attain a harmony between these two contradictory properties and provide a correspondence
between symmetries and conservation laws using the Lagrangian for the evolutionary part of Maxwell’s equations. 相似文献
6.
In this paper we study sequences of vector orthogonal polynomials. The vector orthogonality presented here provides a reinterpretation
of what is known in the literature as matrix orthogonality. These systems of orthogonal polynomials satisfy three-term recurrence
relations with matrix coefficients that do not obey to any type of symmetry. In this sense the vectorial reinterpretation
allows us to study a non-symmetric case of the matrix orthogonality. We also prove that our systems of polynomials are indeed
orthonormal with respect to a complex measure of orthogonality. Approximation problems of Hermite-Padé type are also discussed.
Finally, a Markov’s type theorem is presented. 相似文献
7.
A two dimensional model of the orientation distribution of fibres in a paper machine headbox is studied. The goal is to control
the fibre orientation distribution at the outlet of contraction by changing its shape. The mathematical formulation leads
to an optimization problem with control in coefficients of a linear convection-diffusion equation as the state problem. Then,
the problem is expressed as an optimal control problem governed by variational forms. By using an embedding method, the class
of admissible shapes is replaced by a class of positive Radon measures. The optimization problem in measure space is then
approximated by a linear programming problem. The optimal measure representing optimal shape is approximated by the solution
of this linear programming problem. In this paper, we have shown that the embedding method (embedding the admissible set into
a subset of measures), successfully can be applied to shape variation design to a one dimensional headbox. The usefulness
of this idea is that the method is not iterative and it does not need any initial guess of the solution.
相似文献
8.
With a plane curve singularity one associates a multi-index filtration on the ring of germs of functions of two variables
defined by the orders of a function on irreducible components of the curve. The Poincaré series of this filtration turns out
to coincide with the Alexander polynomial of the curve germ. For a finite set of divisorial valuations on the ring corresponding
to some components of the exceptional divisor of a modification of the plane, in a previous paper there was obtained a formula
for the Poincaré series of the corresponding multi-index filtration similar to the one associated with plane germs. Here we
show that the Poincaré series of a set of divisorial valuations on the ring of germs of functions of two variables defines
“the topology of the set of the divisors” in the sense that it defines the minimal resolution of this set up to combinatorial
equivalence. For the plane curve singularity case, we also give a somewhat simpler proof of the statement by Yamamoto which
shows that the Alexander polynomial is equivalent to the embedded topology. 相似文献
9.
For a small buffer queueing system fed by many flows of a large class of traffic processes we show the single server queue
and associated sample paths behave as if fed by marked Poisson traffic in a large deviations limit.
The timescale of events of interest tends to zero, so we study the log moment generating function as time tends to zero. The
associated rate function depends only on the mean arrival rate and the moment generating function of the arrivals. These results
are useful in estimating drop probabilities while studying the effect of small buffers on communication protocols.
Research supported by EPSRC Grant GR/S86266/01. 相似文献
10.
James East 《Semigroup Forum》2010,81(2):357-379
The (full) transformation semigroup Tn\mathcal{T}_{n} is the semigroup of all functions from the finite set {1,…,n} to itself, under the operation of composition. The symmetric group Sn í Tn{\mathcal{S}_{n}\subseteq \mathcal{T}_{n}} is the group of all permutations on {1,…,n} and is the group of units of Tn\mathcal{T}_{n}. The complement Tn\Sn\mathcal{T}_{n}\setminus \mathcal{S}_{n} is a subsemigroup (indeed an ideal) of Tn\mathcal{T}_{n}. In this article we give a presentation, in terms of generators and relations, for Tn\Sn\mathcal{T}_{n}\setminus \mathcal{S}_{n}, the so-called singular part of Tn\mathcal{T}_{n}. 相似文献
11.
Hidemitsu Wadade 《Journal of Fourier Analysis and Applications》2009,15(6):857-870
We consider the generalized Gagliardo-Nirenberg inequality in $\Bbb{R}^{n}$ including homogeneous Besov space $\dot{B}^{s}_{r,\rho}(\Bbb{R}^{n})$ with the critical order s=n/r, which describes the continuous embedding such as $L^{p}(\Bbb{R}^{n})\cap\dot{B}^{n/r}_{r,\rho}(\Bbb{R}^{n})\subset L^{q}(\Bbb{R}^{n})$ for all q with p ≦ q<∞, where 1≦ p ≦ r<∞ and 1<ρ ≦∞. Indeed, the following inequality holds: $$\|u\|_{L^{q}(\Bbb{R}^{n})}\leqq C\,q^{1-1/\rho}\|u\|_{L^{p}(\Bbb{R}^{n})}^{p/q}\|u\|_{\dot{B}^{n/r}_{r,\rho}(\Bbb{R}^{n})}^{1-p/q},$$ where C is a constant depending only on r. In this inequality, we have the exact order 1?1/ρ of divergence to the power q tending to the infinity. Furthermore, as a corollary of this inequality, we obtain the Gagliardo-Nirenberg inequality with the homogeneous Triebel-Lizorkin space $\dot{F}^{n/r}_{r,\rho}(\Bbb{R}^{n})$ , which implies the usual Sobolev imbedding with the critical Sobolev space $\dot{H}^{n/r}_{r}(\Bbb{R}^{n})$ . Moreover, as another corollary, we shall prove the Trudinger-Moser type inequality in $\dot{B}^{n/r}_{r,\rho}(\Bbb{R}^{n})$ . 相似文献
12.
Géza Tóth 《Discrete and Computational Geometry》2008,39(4):791-799
The crossing number
of a graph G is the minimum possible number of edge-crossings in a drawing of G, the pair-crossing number
is the minimum possible number of crossing pairs of edges in a drawing of G, and the odd-crossing number
is the minimum number of pairs of edges that cross an odd number of times. Clearly,
. We construct graphs with
. This improves the bound of Pelsmajer, Schaefer and Štefankovič. Our construction also answers an old question of Tutte.
Slightly improving the bound of Valtr, we also show that if the pair-crossing number of G is k, then its crossing number is at most O(k
2/log 2
k).
G. Tóth’s research was supported by the Hungarian Research Fund grant OTKA-K-60427 and the Research Foundation of the City
University of New York. 相似文献
13.
G. A. Aminov 《Theoretical and Mathematical Physics》2012,171(2):575-588
We study a limit relation between the elliptic SL(N,?) top and Toda chains. We show that in the case of the nonautonomous SL(2, ?) top, whose equations of motion are related to the Painlevé VI equation, it turns out to be possible to modify the previously proposed procedure and in the limit obtain the nonautonomous Toda chain, whose equations of motion are equivalent to a particular case of the Painlevé III equation. We obtain the limit of the Lax pair for the elliptic SL(2, ?) top, which allows representing the equations of motion of the nonautonomous Toda chain as the equation for isomonodromic deformations. 相似文献
14.
The aim of this paper is to investigate from the numerical point of view the coupling of the Hamilton-Jacobi-Bellman (HJB)
equation and the Pontryagin minimum principle (PMP) to solve some control problems. A rough approximation of the value function
computed by the HJB method is used to obtain an initial guess for the PMP method. The advantage of our approach over other
initialization techniques (such as continuation or direct methods) is to provide an initial guess close to the global minimum.
Numerical tests involving multiple minima, discontinuous control, singular arcs and state constraints are considered. 相似文献
15.
Summary Various questions posed by P. Nyikos concerning ultrafilters on and chains in the partial order (, <*) are answered. The main tool is the oracle chain condition and variations of it.The first author is partially supported by the basic research fund of the Israeli Academy. The second author is partially supported by NSERC and was a guest of Rutgers University while the research on this paper was being done. The authors would also like to thank P. Nyikos for his valuable comments on early versions of this paper. This is number 465 on the first author's list of publications 相似文献
16.
Giuseppe Maria Coclite Angelo Favini Gisèle Ruiz Goldstein Jerome A. Goldstein Silvia Romanelli 《Semigroup Forum》2008,77(1):101-108
The solution u of the well-posed problem
depends continuously on (a
ij
,β,γ,q).
Dedicated to Karl H. Hofmann on his 75th birthday. 相似文献
17.
How to get the timing right. A computational model of the effects of the timing of contacts on team cohesion in demographically diverse teams 总被引:1,自引:0,他引:1
Lau and Murnighan’s faultline theory explains negative effects of demographic diversity on team performance as consequence of strong demographic faultlines. If demographic differences between group members are correlated across various dimensions, the team is likely to show a “subgroup split” that inhibits communication and effective collaboration between team members. Our paper proposes a rigorous formal and computational reconstruction of the theory. Our model integrates four elementary mechanisms of social interaction, homophily, heterophobia, social influence and rejection into a computational representation of the dynamics of both opinions and social relations in the team. Computational experiments demonstrate that the central claims of faultline theory are consistent with the model. We show furthermore that the model highlights a new structural condition that may give managers a handle to temper the negative effects of strong demographic faultlines. We call this condition the timing of contacts. Computational analyses reveal that negative effects of strong faultlines critically depend on who is when brought in contact with whom in the process of social interactions in the team. More specifically, we demonstrate that faultlines have hardly negative effects when teams are initially split into demographically homogeneous subteams that are merged only when a local consensus has developed. 相似文献
18.
Theodore Tachim Medjo 《Applied Mathematics and Optimization》2010,62(1):1-26
We consider a class of stochastic impulse control problems of general stochastic processes i.e. not necessarily Markovian.
Under fairly general conditions we establish existence of an optimal impulse control. We also prove existence of combined
optimal stochastic and impulse control of a fairly general class of diffusions with random coefficients. Unlike, in the Markovian
framework, we cannot apply quasi-variational inequalities techniques. We rather derive the main results using techniques involving
reflected BSDEs and the Snell envelope. 相似文献
19.
In this paper we show that the flow map of the Benjamin-Ono equation on the line is weakly continuous in L 2(?), using “local smoothing” estimates. L 2(?) is believed to be a borderline space for the local well-posedness theory of this equation. In the periodic case, Molinet (Math. Ann. 337, 353–383, 2007) has recently proved that the flow map of the Benjamin-Ono equation is not weakly continuous in $L^{2}(\mathbb{T})In this paper we show that the flow map of the Benjamin-Ono equation on the line is weakly continuous in L
2(ℝ), using “local smoothing” estimates. L
2(ℝ) is believed to be a borderline space for the local well-posedness theory of this equation. In the periodic case, Molinet
(Math. Ann. 337, 353–383, 2007) has recently proved that the flow map of the Benjamin-Ono equation is not weakly continuous in
L2(\mathbbT)L^{2}(\mathbb{T}). Our results are in line with previous work on the cubic nonlinear Schr?dinger equation, where Goubet and Molinet (Nonlinear
Anal. 71, 317–320, 2009) showed weak continuity in L
2(ℝ) and Molinet (Am. J. Math. 130, 635–683, 2008) showed lack of weak continuity in
L2(\mathbbT)L^{2}(\mathbb{T}). 相似文献
20.
R. Monneau 《Journal of Fourier Analysis and Applications》2009,15(3):279-335
In this paper we are interested in pointwise regularity of solutions to elliptic equations. In a first result, we prove that
if the modulus of mean oscillation of Δu at the origin is Dini (in L
p
average), then the origin is a Lebesgue point of continuity (still in L
p
average) for the second derivatives D
2
u. We extend this pointwise regularity result to the obstacle problem for the Laplace equation with Dini right hand side at
the origin. Under these assumptions, we prove that the solution to the obstacle problem has a Taylor expansion up to the order
2 (in the L
p
average). Moreover we get a quantitative estimate of the error in this Taylor expansion for regular points of the free boundary.
In the case where the right hand side is moreover double Dini at the origin, we also get a quantitative estimate of the error
for singular points of the free boundary.
Our method of proof is based on some decay estimates obtained by contradiction, using blow-up arguments and Liouville Theorems.
In the case of singular points, our method uses moreover a refined monotonicity formula.
相似文献