A Result in Dual Ramsey Theory

We present a result which is obtained by combining a result of Carlson with the Finitary Dual Ramsey Theorem of Graham–Rothschild.     

On Automorphisms of Some d-Dimensional Dual Hyperovals in PG(d(d + 3)/2, 2)

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.     

A note on the characteristic classes of non-positively curved manifolds

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.     

Relating the multiple supply problem to quantity flexibility contracts

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.     

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.     

A numerically stable dual method for solving strictly convex quadratic programs

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.     

基于（TI）C6711浮点DSP的双音多频信号检测的实现

双音多频DTMF(Dual Tone Multi—Frequency)信号是音频电话中的拔号信号，将DTMF信号的检测集成到含有数字信号处理器(DSP)的系统中，是一项较有价值的实际课题．本文给出在TI公司浮点DSP芯片C6711中的实现方案，通过20个并行的哥兹柔信号滤波器成成功地使双音多频信号检测变得准确、迅速和简单。     

最小交互熵在投入─产出表理论预测的应用

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．     

Dual variational principles with deviating argument and discontinuous extremals

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.