基于承包商预期收益不变的不平衡报价模型

在招标实践中,通常采用最低价中标原则,使得投标人不得不压低其投标价格。基于承包商预期收益不变的不平衡报价模型,是在“工程量清单报价”的条件下,考虑到施工中工程量的变化及施工顺序的影响,体现了资金的时间价值,在保持承包商预期收益不变的前提下,通过调整各分项工程的单价,来降低工程报价,以增加中标机会而建立的。所建立的模型简单,易于操作,并配以具体的工程实例,通过计算机求得其最优解,可供承包商投标报价时参考。     

A note on the value function for constrained control problems

We consider the Mayer optimal control problem with dynamics given by a nonconvex differential inclusion, whose trajectories are constrained to a given set and we obtain a relation between the costate function that appears in the maximum principle and the value function. This relation extends the known conditions existing in the literature for unconstrained problems to those for problems under state constraints.     

VFP环境下报表设计研究

Visual FoxPro是小型数据库应用系统开发工具,而报表设计是数据库应用系统开发的一个重要组成部分,直接决定系统的输出是否能够满足用户的需要。为此详细研究了报表设计方法,结合Microsoft的OLE技术,引入面向对象方法,提出了一种新的报表设计方法。实践应用证明,该方法非常适合设计复杂的报表。     

石化企业线性规划模型的自动生成

根据石化企业生产过程的实际情况，考虑原料供应量、装置加工能力、物料平衡和价格等情况．建芷反映企业生产情况的线性规划数学模型。分别阐述了模型的决策变量、目标函数和约束方程的自动生成的方法，并给出了模型文件的存储结构。     

水资源系统分析法在水资源优化配置中的应用

探讨了水资源系统分析法的步骤和数学模型,并以线性规划模型为例建立了水资源优化配置的数学模型,对水资源优化配置提供了一定的依据。     

HART通信协议在汽油机速度测量和监控方面的应用

首先介绍了HART通信协议及他的优点，然后介绍了HART通信协议在汽油机测速方面的软件实现。该软件主要采用目前流行的VB编程语言。可设计出界面友好、功能强大的测量和监控软件。     

Wavelength and Waveband Assignment for Ring Networks Based on Parallel Multi‐granularity Hierarchical OADMs

In this paper we study the optimization issues of ring networks employing novel parallel multi‐granularity hierarchical optical add‐drop multiplexers (OADMs). In particular, we attempt to minimize the number of control elements for the off‐line case. We present an integer linear programming formulation to obtain the lower bound in optimization, and propose an efficient heuristic algorithm called global bandwidth resource assignment that is suitable for the design of large‐scale OADM networks.     

Protecting local access telecommunications networks: Toward a minimum-cost solution

The problem of designing fibre-optic networks for local-access telecommunications generates (at least) three non-trivial subproblems. In the first of these subproblems one must determine how many fibre-optic cables (fibres) are required at either end of a street. In the next subproblem a minimum-cost network must be designed to support the fibres. The network must also provide distinct paths from either end of the street to the central exchange(s). Finally, the fibre-optic cables must be placed in protective covers. These covers are available in a number of different sizes, allowing some flexibility when covering each section of the network. In this paper we describe a dynamic programming (DP) formulation for finding a minimum-cost (protective) covering for the network (the third of the subproblems). This problem is a generalised set covering problem with side constraints and is further complicated by the introduction of fixed and variable welding costs. The DP formulation selects covers along each arc (in the network), but cannot exactly model the fixed costs and so does not guarantee optimality. We also describe an integer programming (IP) formulation for assessing the quality of the DP solutions. The cost of the networks constructed by the IP model is less than those designed using the DP model, but the saving is not significant for the problems examined (less than 0.1%). This indicates that the DP model will generally give very good solutions. Furthermore, as the problem dimensions grow, DP gives significantly better solution times than IP.     

分析介质光波导传播特性的Cole—Hopf变换法

采用Cole-Hopf变换法，将平板光波导导模所满足的二阶常微分方程（Helmholtz方程）变换成一阶常微分方程（Riccati方程），用较简单且有效的方法分析导模的特性。给出了多层阶跃型及渐变型平板波导导模的精确解析解和数值解法及实例；给出了非线性平板波导传播特性的数值计算法及实例。     

An original approximate method for estimating the invariant probability distribution of a large class of multi-dimensional nonlinear stochastic oscillators

This paper proposes an original method for obtaining analytical approximations of the invariant probability density function of multi-dimensional Hamiltonian dissipative dynamic systems under Gaussian white noise excitations, with linear non-conservative parts and nonlinear conservative parts. The method is based on an exact result and a heuristic argument. Its pertinence is attested by numerical tests.