Multicommodity network flows: The impact of formulation on decomposition

This paper investigates the impact of problem formulation on Dantzig—Wolfe decomposition for the multicommodity network flow problem. These problems are formulated in three ways: origin-destination specific, destination specific, and product specific. The path-based origin-destination specific formulation is equivalent to the tree-based destination specific formulation by a simple transformation. Supersupply and superdemand nodes are appended to the tree-based product specific formulation to create an equivalent path-based product specific formulation. We show that solving the path-based problem formulations by decomposition results in substantially fewer master problem iterations and lower CPU times than by using decomposition on the equivalent tree-based formulations. Computational results on a series of multicommodity network flow problems are presented.This paper is dedicated to Phil Wolfe on the occasion of his 65th birthday.     

组织合作中关系专用性投资最优水平分析

本在以往研究的基础上对关系专用投资的价值创造功能作了进一步的讨论，分析了其创造准租金收入的机理和一般表示，在此基础上结合以往交易成本经济学对关系专用性投资的认识以及其作为沉没成本的特征，从效用最大化的角度建立了两个成员的联盟中关系专用性投资的决策模型，分析了关系专用性投资创造准租的具体特征对投资水平的影响。     

比热容非常值对高超声速平板边界层稳定性的影响

在高超声速条件下,边界层中气体的温度可能很高,以致气体的比热容不再是常数而与温度有关．这时边界层中的流动稳定性如何是值得研究的问题．采用线性稳定性理论,考虑比热容与温度有关时高超声速可压缩平板边界层的稳定性,并与假定比热容为常值的情况作比较,发现对第一模态和第二模态波的中性曲线、最大增长率都有影响．因此,在高超声速情况下,比热容随温度变化是研究边界层稳定性时必须考虑的一个因素．     

三角形网格的有效性分析

本文分析了利用三角形网格对π作统计估计的有效性,首先对任意三角形网格进行一般性的分析,得出了具体的表达式,又对等边三角形网格和等腰直角三角形网格两种特殊情形进行具体计算,得出了具体的数值.     

企业员工专用性人力资本投资的模型分析

企业对员工的人力资本投资进行适宜的激励,对于提高组织的绩效、提高企业的价值具有重要作用.将员工的人力资本投资细分为企业专用性人力资本投资与经理专用性人力资本投资,并认为因其不同功能企业则偏向于员工进行企业专用性人力资本投资,在此基础上通过建立数学模型,分析了企业与员工合作与非合作两种情况下企业与员工各自的收益及企业分配给员工的报酬比例、员工对企业及经理的投资均衡等相关问题.     

A theory for synchronization of dynamical systems

In this paper, a theory for synchronization of multiple dynamical systems under specific constraints is developed from a theory of discontinuous dynamical systems. The concepts on synchronization of two or more dynamical systems to specific constraints are presented. The synchronization, desynchronization and penetration of multiple dynamical systems to multiple specified constraints are discussed, and the necessary and sufficient conditions for such synchronicity are developed. The synchronicity of two dynamical systems to a single specific constraint and to multiple specific constraints is investigated. Finally, the synchronization and the corresponding complexity for multiple slave systems with multiple master systems are discussed briefly. The meaning of synchronization for dynamical systems with constraints is extended as a generalized, universal concept. The theory presented in this paper may be as a universal theory for dynamical systems. The paper provides a theoretic frame work in order to control slave systems which can be synchronized with master systems through specific constraints in a general sense.     

Empirical Evaluation of Hybrid Defaultable Bond Pricing Models

A four‐factor model (the extended model of Schmid and Zagst) is presented for pricing credit risk related instruments such as defaultable bonds or credit derivatives. It is an advancement of an earlier three‐factor model. In addition to a firm‐specific credit risk factor, a new systematic risk factor in the form of GDP growth rate is included. This new model is set in the context of other hybrid defaultable bond pricing models and empirically compared to specific representatives. We find that a model based only on firm‐specific variables is unable to capture changes in credit spreads completely. However, it is shown that in this model, market variables such as GDP growth rates, non‐defaultable interest rates and firm‐specific variables together significantly influence credit spread levels and changes.     

Optimization methods for pipeline transportation of natural gas with variable specific gravity and compressibility

In this paper, the problem of flow maximization in pipeline systems for transmission of natural gas is addressed. We extend previously suggested models by incorporating the variation in pipeline flow capacities with gas specific gravity and compressibility. Flow capacities are modeled as functions of pressure, compressibility and specific gravity by the commonly-used Weymouth equation, and the California Natural Gas Association method is used to model compressibility as a function of specific gravity and pressure. The sources feeding the transmission network do not necessarily supply gas with equal specific gravity. In our model, it is assumed that when different flow streams enter a junction point, the specific gravity of the resulting flow is a weighted average of the specific gravities of entering flows. We also assume the temperature to be constant, and the system to be in steady state. Since the proposed model is non-convex, and global optimization hence can be time consuming, we also propose a heuristic method based on an iterative scheme in which a simpler NLP model is solved in each iteration. Computational experiments are conducted in order to assess the computability of the model by applying a global optimizer, and to evaluate the performance of the heuristic approach. When applied to a wide set of test instances, the heuristic method provides solutions with deviations less than 10% from optimality, and in many instances turns out to be exact. We also report several experiments demonstrating that letting the compressibility and the specific gravity be global constants can lead to significant errors in the estimates of the total network capacity.     

Machine dependent programming in common languages

It is suggested that we should distinguish between common programming languages and common solutions to specific problems. A solution may depend on specific machine characteristics even though it is expressed in a common language. It is further suggested that in future common programming languages this should be admitted openly by allowing the programmer to get access to the machine characteristics at hand through Environment Enquiries which are part of the language. Some specific examples of Environment Enquiries are given.An earlier version of this paper was published in ALGOL BULLETIN no. 18, October 1964.     

A Learning Framework for Neural Networks Using Constrained Optimization Methods

Conventional supervised learning in neural networks is carried out by performing unconstrained minimization of a suitably defined cost function. This approach has certain drawbacks, which can be overcome by incorporating additional knowledge in the training formalism. In this paper, two types of such additional knowledge are examined: Network specific knowledge (associated with the neural network irrespectively of the problem whose solution is sought) or problem specific knowledge (which helps to solve a specific learning task). A constrained optimization framework is introduced for incorporating these types of knowledge into the learning formalism. We present three examples of improvement in the learning behaviour of neural networks using additional knowledge in the context of our constrained optimization framework. The two network specific examples are designed to improve convergence and learning speed in the broad class of feedforward networks, while the third problem specific example is related to the efficient factorization of 2-D polynomials using suitably constructed sigma-pi networks.     

Hamacher算子的一个新性质及其应用

完善了Hamacher算子的定义;发现了Hamacher算子的一个新性质;分析了Hamacher算子与其它模糊算子之间的关系。最后,根据Hamacher算子的新性质,给出了一个新的模糊评判的方法。     

L~1空间中弱奇性积分方程特征值的数值解法探究

在L¹空间中讨论弱奇性积分方程的特征值问题,给出了一种算法,证明所提出算法的合理性,并举出具体算例,通过Matlab编程算出所给算例的近似数值解.     

轧板过程中单位压力的分布规律

轧板时单位压力的分布规律不仅用于计算总轧制力的数值,而且提供计算宽展、设计合理辊型的依据.然而迄今文献上所进行的分析,绝大部分只限于一维表达,不能反映单位压力沿变形区宽度上的变化.本文从变分法的原理出发,得出单位压力分布规律的二维表达式.     

Bipartite Locating Array

As a special case of experimental design,locating array is useful for locating interaction faults in component-based systems.In this paper,bipartite locating array is proposed to locate interaction faults between two specific groups.Such arrays are especially suitable for antagonism tests.Based on the definition of bipartite locating array,the lower bound on run sizes are established to measure the optimality for specific parameters.When a single fault is to be located,optimal bipartite locating arrays are proved to be equivalent to certain specific combinatorial configurations.As a result,approaches to constructing optimal bipartite locating arrays are proposed and some infinite classes of optimal bipartite locating arrays are obtained using the corresponding construction met hod.     

一个特定型定积分不等式的若干推广

通过适当构造辅助函数和应用牛顿—莱布尼兹公式、施瓦兹积分不等式,将一个特定型定积分不等式进行了推广.证明了只要被积函数在积分区间内存在零点,该特定型定积分不等式均成立,进而给出实例说明了该不等式成立的正确性.     

A multivariate time series approach to projected life tables

The method of mortality forecasting proposed by Lee and Carter describes a time series of age‐specific log‐death rates as a sum of an independent of time age‐specific component and a bilinear term in which one of the component is a time‐varying factor reflecting general change in mortality and the second one is an age‐specific parameter. Such a rigid model structure implies that on average the mortality improvements for different age groups should be proportional, regardless of the calendar period: a single time factor drives the future death rates. This paper investigates the use of multivariate time series techniques for forecasting age‐specific death rates. This approach allows for relative speed of decline in the log death rates specific to the different ages. The dynamic factor analysis and the Johansen cointegration methodology are successfully applied to project mortality. The inclusion of several time factors allows the model to capture the imperfect correlations in death rates from 1 year to the next. The benchmark Lee–Carter model appears as a special case of these approaches. An empirical study is conducted with the help of the Johansen cointegration methodology. A vector‐error correction model is fitted to Belgian general population death rates. A comparison is performed with the forecast of life expectancies obtained from the classical Lee–Carter model. Copyright © 2009 John Wiley & Sons, Ltd.     

Simulation input data modeling

Input data modeling is a critical component of a successful simulation application. A perspective of the area is given with an emphasis on available probability distributions as models, estimation methods, model selection and discrimination, and goodness of fit. Three specific distribution classes (lambda,S _B , TES processes) are discussed in some detail to illustrate characteristics that favor input models. Regarding estimation, we argue for maximum likelihood estimation over method of moments and other matching schemes due to intrinsic superior properties (presuming a specific model) and the capability of accommodating messy data types. We conclude with a list of specific research problems and areas warranting additional attention.     

The small anisotropy formulation of elastic deformation

The specific internal energy defines the constitutive relation (stress-strain function) in elastic deformations. We introduce a form for the specific internal energy that expresses the idea of small anisotropy. In this formulation, only one parameter is needed to specify the anisotropic part of the deformation.Supported in part by AFOSR-88-0025.     

Solving problems of project management with a self enforcing network (SEN)

The usage of AI techniques when dealing with problems of management always implies the task to understand the respective problem in terms of these techniques, in this case in terms of a specific neural network. That is, by the way, at its core a hermeneutical problem, namely of ??understanding?? the problem situation in the sense of hermeneutics. I shall demonstrate how a specific self-organized learning network that we have newly developed can be applied to problems of project management. This new network SEN will be described and its possibilities are shown by the application to different problems of project management, e.g. the selection of suited collaborators for a specific project, the classification of problematic customers or also the selection of suited procedures for project management in a specific firm. The SEN seems to be a universal instrument for different purposes as many reactions from managers in several large firms have shown. In particular SEN seems to be more suited for practical problems than some standard software we compared with SEN.     

复Banach空间上推广的Roper-Suffridge算子

从定义出发证明复Banach空间特定域上推广的Roper-Suffridge算子保持α次强β型螺形性及ρ次抛物型β型螺形性,由此得到推广后的算子在复Banach空间特定域上保持α次强星形性、ρ次抛物星形性及抛物星形性,为由复平面C中单位圆盘D上的α次强β型螺形映照及ρ次抛物β型螺形映照来构造复Banach空间特定域上相应的映照提供了一种新的途径,充实了对Roper-Suffridge算子的研究.