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941.
Hiroaki Taniguchi 《Graphs and Combinatorics》2008,24(3):229-236
In [3], a new d-dimensional dual hyperoval S in PG(d(d + 3)/2, 2) for d ≥ 3 was constructed based on Veronesean dual hyperoval. In this note, we determine the automorphism group of the dual hyperoval
S.
Received: January 26, 2007. Final Version received: January 7, 2008. 相似文献
942.
In this expository note, we give a simple conceptual proof of the Hirzebruch proportionality principle for Pontrjagin numbers of non-positively curved locally symmetric spaces. We also establish (non)-vanishing results for Stiefel–Whitney and Pontrjagin numbers of (finite covers of) the Gromov–Thurston examples of compact negatively curved manifolds. A byproduct of our argument gives a constructive proof of a well-known result of Rohlin: every closed orientable 3-manifold bounds orientably. We mention some geometric corollaries: a lower bound for degrees of covers having tangential maps to the non-negatively curved duals and estimates for the complexity of some representations of certain uniform lattices. 相似文献
943.
Özgür Yazlali 《Operations Research Letters》2007,35(6):767-772
We consider two classes of problems in the supply chain management literature: the multiple supply problem and quantity flexibility contracts. We identify the similarities between these two problems and show that for both the total operating cost of the manufacturer is convex with respect to its arguments under mild conditions. 相似文献
944.
Lagrangian heuristics for scheduling new product development projects in the pharmaceutical industry
To stay ahead of their competition, pharmaceutical firms must make effective use of their new product development (NPD) capabilities
by efficiently allocating its analytical, clinical testing and manufacturing resources across various drug development projects.
The resulting project scheduling problems involve coordinating hundreds of testing and manufacturing activities over a period
of several quarters. Most conventional integer programming approaches are computationally impractical for problems of this
size, while priority rule-driven heuristics seldom provide consistent solution quality. We propose a Lagrangian decomposition
(LD) heuristic that exploits the special structure of these problems. Some resources (typically manpower) are shared across
all on-going projects while others (typically equipment) are specific to individual project categories. Our objective function
is a weighted discounted cost expressed in terms of activity completion times. The LD heuristics were subjected to a comprehensive
experimental study based on typical operational instances. While the conventional “Reward–Risk” priority rule heuristic generates
duality gaps between 47–58%, the best LD heuristic achieves duality gaps between 10–20%. The LD heuristics also yield makespan
reductions of over 30% over the Reward–Risk priority rule. 相似文献
945.
An efficient and numerically stable dual algorithm for positive definite quadratic programming is described which takes advantage
of the fact that the unconstrained minimum of the objective function can be used as a starting point. Its implementation utilizes
the Cholesky and QR factorizations and procedures for updating them. The performance of the dual algorithm is compared against
that of primal algorithms when used to solve randomly generated test problems and quadratic programs generated in the course
of solving nonlinear programming problems by a successive quadratic programming code (the principal motivation for the development
of the algorithm). These computational results indicate that the dual algorithm is superior to primal algorithms when a primal
feasible point is not readily available. The algorithm is also compared theoretically to the modified-simplex type dual methods
of Lemke and Van de Panne and Whinston and it is illustrated by a numerical example.
This research was supported in part by the Army Research Office under Grant No. DAAG 29-77-G-0114 and in part by the National
Science Foundation under Grant No. MCS-6006065. 相似文献
946.
947.
本文利用最小交互熵的概念和有关结论,直接地给出具有固定边际的投入─产出表预测模型的RAS方法的结构形式;同时利用信息论中的不等式,直接地证明最小交互熵解就是对偶几何规划解;从而简单、明了地赋于投入─产出表RAS方法的信息意义.我们还给出一种迭代计算方案.最后指出,该方法可以用统计方法检验新的理论预测与原投入─产出表的差异性. 相似文献
948.
We study dual or complementary variational principles for functionals with deviating argument and discontinuous extremals. Local conditions for the existence of a pair of dual extremum principles are given. Results are then applied to the control problem involving linear neutral differential-difference equations. 相似文献
949.
本文采用Raman-Maxwell-Bloch方程,计算了宽频带聚焦泵浦准稳态受激电子喇曼散射的增益因子和能量转换效率.在计算中考虑了泵浦抽空、喇曼介质对泵浦光的吸收和喇曼介质的泡和效应.计算结果与XeCl激光在钡蒸汽中的受激喇曼散射实验基本上符合. 相似文献
950.
关于半无限规划的对偶间隙 总被引:3,自引:0,他引:3
李师正 《数学物理学报(A辑)》2000,20(1):1-5
该文对半无限凸规划(P)提出了一个对偶问题(D1),证明了(D1)与(P)无对偶间隙当且仅当Lagrange对偶问题(D)与(P)之间无对偶间隙,作者还利用方向导数给出一个新的刻划鞍点准则的方法。 相似文献