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51.
Order Acceptance (OA) is one of the main functions in business control. Accepting an order when capacity is available could
disable the system to accept more profitable orders in the future with opportunity losses as a consequence. Uncertain information
is also an important issue here. We use Markov decision models and learning methods from Artificial Intelligence to find decision
policies under uncertainty. Reinforcement Learning (RL) is quite a new approach in OA. It is shown here that RL works well
compared with heuristics. It is demonstrated that employing an RL trained agent is a robust, flexible approach that in addition
can be used to support the detection of good heuristics. 相似文献
52.
Order batching problem (OBP) is the problem of determining the number of orders to be picked together in one picking tour. Although various objectives may arise in practice, minimizing the average throughput time of a random order is a common concern. In this paper, we consider the OBP for a 2-block rectangular warehouse with the assumptions that orders arrive according to a Poisson process and the method used for routing the order-pickers is the well-known S-shape heuristic. We first elaborate on the first and second moment of the order-picker’s travel time. Then we use these moments to estimate the average throughput time of a random order. This enables us to estimate the optimal picking batch size. Results from simulation show that the method provides a high accuracy level. Furthermore, the method is rather simple and can be easily applied in practice. 相似文献
53.
Joseph Y.-T. Leung 《Discrete Applied Mathematics》2007,155(8):945-970
We consider the problem of scheduling orders for multiple different product types in an environment with m dedicated machines in parallel. The objective is to minimize the total weighted completion time. Each product type is produced by one and only one of the m dedicated machines; that is, each machine is dedicated to a specific product type. Each order has a weight and may also have a release date. Each order asks for certain amounts of various different product types. The different products for an order can be produced concurrently. Preemptions are not allowed. Even when all orders are available at time 0, the problem has been shown to be strongly NP-hard for any fixed number (?2) of machines. This paper focuses on the design and analysis of efficient heuristics for the case without release dates. Occasionally, however, we extend our results to the case with release dates. The heuristics considered include some that have already been proposed in the literature as well as several new ones. They include various static and dynamic priority rules as well as two more sophisticated LP-based algorithms. We analyze the performance bounds of the priority rules and of the algorithms and present also an in-depth comparative analysis of the various rules and algorithms. The conclusions from this empirical analysis provide insights into the trade-offs with regard to solution quality, speed, and memory space. 相似文献
54.
Let I be a finite interval, s ∈ ℕ0, and r,ν,n ∈ ℕ. Given a set M, of functions defined on I, denote by
M the subset of all functions y ∈ M such that the s-difference is nonnegative on I, ∀τ > 0. Further, denote by the Sobolev class of functions x on I with the seminorm . Also denote by Σ
ν,n
, the manifold of all piecewise polynomials of order ν and with n – 1 knots in I. If ν ≥ max {r,s}, 1 ≤ p,q ≤ ∞, and (r,p,q) ≠ (1,1,∞), then we give exact orders of the best unconstrained approximation and of the best s-monotonicity preserving approximation .
Part of this work was done while the first author visited Tel Aviv University in May 2003 and in March 2004. 相似文献
55.
一类广义AHP判断下的保序性问题 总被引:1,自引:0,他引:1
本讨论了一类基于两组元素比较的广义AHP判断下所用排序方法的保序性,并提出了一种特殊的广义判断阵,四四比较判断矩阵,供实际操作时参考。 相似文献
56.
广义Gelfand模型的正解 总被引:20,自引:2,他引:20
姚庆六 《高校应用数学学报(A辑)》2001,16(4):407-413
在不要求极限limτ→0f(τ)/τ,limτ→∞f(τ)τ存在的情况下,讨论了二阶边值问题u″(t) λh(t)f(u(t))=0,0≤t≤1,u(0)=u(1)=0的正解存在性和多重性。 相似文献
57.
Two linear orderings of a same set are perpendicular if the only self-mappings of this set that preserve them both are the identity and the constant mappings. Two linear orderings are orthogonal if they are isomorphic to two perpendicular linear orderings. We show that two countable linear orderings are orthogonal as soon as each one has two disjoint infinite intervals. From this and previously known results it follows in particular that each countably infinite linear ordering is orthogonal to itself. 相似文献
58.
Mean-value theorems and extensions of the Elliott-Daboussi theorem on additive arithmetic semigroups
Wen-Bin Zhang 《The Ramanujan Journal》2008,15(1):47-75
We present more general forms of the mean-value theorems established before for multiplicative functions on additive arithmetic
semigroups and prove, on the basis of these new theorems, extensions of the Elliott-Daboussi theorem. Let
be an additive arithmetic semigroup with a generating set ℘ of primes p. Assume that the number G(m) of elements a in
with “degree” ∂(a)=m satisfies
with constants q>1, ρ
1<ρ
2<⋅⋅⋅<ρ
r
=ρ, ρ≥1, γ>1+ρ. For the main result, let α,τ,η be positive constants such that α>1,τ
ρ≥1, and τ
α
ρ≥1. Then for a multiplicative function f(a) on
the following two conditions (A) and (B) are equivalent. These are (A) All four series
converge and
and (B) The order τ
ρ mean-value
exists with m
f
≠0 and the limit
exists with M
v
(α)>0.
相似文献
59.
A poset P=(X,) is m-partite if X has a partition X=X1Xm such that (1) each Xi forms an antichain in P, and (2) xy implies xXi and yXj where i<j. In this article we derive a tight asymptotic upper bound on the order dimension of m-partite posets in terms of m and their bipartite sub-posets in a constructive and elementary way. 相似文献
60.
研究 Frame格上的一类等价关系 ,给出 L - Fuzzy伴随的若干性质定理及其等价刻画 ,体现了L- Fuzzy伴随的层次伴随特点 ,最后引入广义 L-值偏序集的概念 ,得到了类似经典伴随的若干特征定理。 相似文献