The Leontief Pollution Model: A Systematic Formulation

In a recent article in this journal, Qayum offered a reformulation of the Leontief pollution model. Here, a systematic formulation of this model is offered which integrates the numerical examples of both Leontief and Qayum.     

Reconsideration of Non-negative Solutions for the Augmented Leontief Model

We consider the Leontief model augmented with pollution-generation and pollution-abatement sectors. The conditions to ensure the existence of non-negative solutions for the total output and for the vector of abatement activities, depending on the exogenously given final demand and environmental standards, are presented. They are extensions and modifications of the conditions for a single pollutant derived, for example, by Miller and Blair.     

影子价格在资源配置中的一个误用及其判定方法

影子价格在资源的配置中具有重要的指导意义,但是在应用时如果不考虑资源约束项的应用范围,得出的结果将不具备指导性。运用影子价格的边际定义对其与资源常数项的关系进行考察,通过理论与实例分析影子价格在资源配置时的有效范围,避免影子价格的误用。     

Non-Parametric Production Analysis of Pesticides Use in the Netherlands

Many previous empirical studies on the productivity of pesticides suggest that pesticides are under-utilized in agriculture despite the general held believe that these inputs are substantially over-utilized. This paper uses data envelopment analysis (DEA) to calculate non-parametric measures of the value of the marginal product of pesticides. Furthermore, the effect of pesticides on the value of the marginal product of productive inputs is investigated in order to analyze technical interdependence between pesticides and productive inputs. Results suggest, in general, substantial under-utilization of pesticides, which is consistent with earlier findings of parametric specifications.     

The Dynamic Leontief Model and the Theory of Endogenous Growth

This paper shows that the dynamic Leontief model can be interpreted as a linear model of endogenous growth. The long-term rate of growth is determined within the economic system - either as the outcome of the saving and investment behaviour of agents or as the outcome of some planner's maximization of some objective function.     

The Loading Optimization: A Novel Integer Linear Programming Model

ABSTRACT

This paper establishes a new integer linear programming model for container loading problem. This model can be used to calculate the optimal loading plan for each container. To solve the model, in this paper, the model problem is decomposed into two easy to solve sub-problems: auxiliary problem (AP) and transportation problem, and prove by solving the two sub-problems can quickly and efficiently to find the optimal solution of the model. Finally, an example is given to illustrate the solution process, which shows that the algorithm can give the optimal stowage scheme quickly and effectively.     

物流网络路径优化模型的探究

基于山东省的地理特点,在若干假设前提下研究从供应商到制造厂,再从制造厂到物流中心的三点二层的线性规划问题的最优解。由于涉及节点较多,不方便运用运筹学上的单纯形法和表上作业法,而用到一种专门求解优化模型的软件即LINGO软件。经过若干组数据的比较和规律总结,得出山东省基于三点两层物流问题的最优路径,并确定所选路径上的运输量以及最低的物流成本。     

供水管网模糊优化设计数学模型研究

供水管网优化设计通常具有模糊性，即影响管网优化设计的某些因素难以准确确定。针对这一特点，建立了供水管网模糊优化设计数学模型。通过变换，将模糊线性规划问题转化成一般线性规划问题，用单纯形法求解。根据所建立的管网模糊优化设计模型，可确定模糊环境下供水管网优化设计方案，与普通线性规划问题相比，该方法使设计结果更为经济合理。     

基于重心法的外商直接投资与我国环境污染关系研究

利用重心分析的方法,对我国1987年—2004年间我国实际吸收外商直接投资量和六类污染指标排放量的重心移动路径进行描绘和关联分析,发现外商直接投资对于我国环境污染程度并无直接的影响。并通过考察外商直接投资在39类工业行业中的比重,以及这些行业产生污染排放的状况,从原因上进一步解释了这一结论。     

A Turnpike Theorem in the Closed Dynamic Leontief Model with a Singular Matrix of Capital Coefficients

The paper refers to the well-known Tsukui turnpike theorem on convergence of optimal growth trajectories in the closed dynamic Leontief model to the maximum balanced growth trajectory, called turnpike. In the original proof of this theorem, the assumption that the matrix B of capital coefficients is non-singular plays an essential role. For many reasons this assumption, very convenient for theoretical analysis, is not always satisfied in input-output systems built for empirical purposes. This paper fills the gap between theory and empirical studies, presenting a proof that convergence of optimal trajectories towards the turnpike is also a characteristic feature of the closed Leontief model in the case when matrix B is singular. The general idea of the proof is based on the approximation of a singular matrix B by an infinite sequence of non-singular matrices.     

A Structural Decomposition Analysis of Pollution in the Netherlands

This paper reviews the results of a structural decomposition analysis in which the annual changes in a number of air pollutants and solid waste are decomposed according to their causes. The analysis in this paper is applied with the help of the so-called National Accounting Matrix including Environmental Accounts (NAMEA) for the Netherlands, covering annual data for the period 1987-1998. In a sensitivity analysis it is shown that the average of any pair of so-called 'mirror image' decomposition forms will substantially reduce the variation in the estimates. These mirror image couples are approximately just as reliable as the full average of all decomposition forms. Besides reliable results, the full average also foresees the mutual comparability between the distinguished change factors and is therefore applied in the empirical analyses presented in this paper. The results of these analyses contain the macro-economic developments, results on the industry level as well as a comprehensive overview of the origin and destination of pollution in the Dutch economy that includes the environmental consequences of consumption and international trade.     

A Multiregional Impact Assessment Model for disaster analysis

This paper presents a recursive dynamic multiregional supply-use model, combining linear programming and input–output (I–O) modeling to assess the economy-wide consequences of a natural disaster on a pan-European scale. It is a supply-use model which considers production technologies and allows for supply side constraints. The model has been illustrated for three floods in Rotterdam, The Netherlands. Results show that most of the neighboring regions gain from the flood due to increased demand for reconstruction and production capacity constraints in the affected region. Regions located further away or neighboring regions without a direct export link to the affected region mostly suffered small losses. These losses are due to the costs of increased inefficiencies in the production process that have to be paid for by all (indirectly) consuming regions. In the end, the floods cause regionally differentiated welfare effects.     

基于线性规划和灰色关联投影法的资本结构优化模型

本文阐述了资本结构的优化目标,结合线性规划与灰色关联投影法构建了一个资本结构优化模型。     

试论建设工程计价依据中人工成本转型管理

本文对目前建设工程计价依据中人工成本管理现状,背景及存在问题作了简述,对人工成本,劳动市场相关理论及文献进行了简要综述与对照评析,对人工成本管理应如何面对现实,开拓思路,确立方向,转型管理问题进行了分析论述,提出了人工成本转型管理应重点突破与解决的几个问题。     

基于LINGO的带转运中心运输管理问题线性规划建模及求解

研究了多生产地、多销售地同时带多个中转站的运输转运问题,考虑了更符合实际的生产地和销售地也能作为中转站的情况,通过在中转站点中添加代表生产地和销售地的虚拟站点,得到求解该问题的虚拟转运网络图,进一步得到相应的线性规划模型,最后基于LINGO优化软件求解了一个运输转运问题实例,验证了模型的正确性。     

A Revision of the Tolerable Limits Approach: Searching for the Important Coefficients

A wide range of approaches are available for classifying coefficients according to their importance to an economy. The ‘tolerable limits’ approach is one that has been extensively written about. Nevertheless, it seems unsuitable for assessing the overall importance of a coefficient to an economy, but instead appears to be rather well suited for determining how much a selling sector depends upon its customers. We therefore suggest two alternative approaches for measuring a sector's importance to an economy. The first is an application of the concept of elasticity based on Sherman and Morrison's (1950) formula. The second approach applies linear programming. We compare these various alternatives using the domestic IO tables of eight European countries.     

震后模糊道路破损率条件下应急物资调配研究

应急物资调配是应急物流系统重要研究问题之一,直接关系到应急物流活动的成败。考虑到灾后运输道路破损率不能立即确定,构建了道路破损率与物资需求量为梯形模糊数的多目标应急物资调配模型。通过将其转化为具有确定系数的多目标规划模型来进行求解,并提出了求得该模型满意解的算法。最后通过算例分析说明该方法的有效性。     

电子产品逆向物流网络规划模型研究

在分析和比较各类回收网络特点的基础上,提出了一种适合中国电子废弃物回收物流管理和分析的正逆向集成回收网络结构,该结构较现有其他研究将维修/退货产品及二手市场收益作为考虑要素,在此基础上考虑到电子废弃物回收过程的不确定性,建立了基于混合整数线性规划(MILP)方法的以网络建设和运营费用最小为目标函数的物流网络模型,并采用案例数据对模型的适用性加以验证。     

A Property of the Leontief Inverse and its Applications to Comparative Static Analysis

We arbitrarily choose a submatrix of order 2 in the Leontief inverse matrix B . If a main diagonal element in the submatrix is a main diagonal element in B , then the determinant of the submatrix is non-negative; in particular, if the two main diagonal elements in the submatrix are all the main diagonal elements in B , then the determinant of the submatrix is greater than or equal to 1. This property can be used in the comparative static analysis for the input-output model. For example, when the change only occurs in one sectoral final demand or one corresponding row of the input coefficient matrix, which leads to a change of this sectoral gross output, the equivalent conditions that the absolute value of the rate of change of this sectoral gross output is larger than or equal to all other sectoral change rates and larger than at least one sectoral rate of change are shown. It is impossible to derive the exact results for the comparative static analysis if the property is not applied. A previous fault confirms this point.     

中小港口企业云计算模型的构建

首先简要介绍了云计算的概念并分析其特点,然后在详细分析了中小港口企业作业管理方式的基础上,对中小港口企业的信息化建设方式进行了分析,指出了传统信息化建设方式在中小港口企业应用方面的不足。并结合广州黄埔港公司、新港公司、石化公司和东莞海昌公司信息化建设实例,应用云计算解决方案,提出了港口企业新的信息化建设方案,构建了基于云计算的港口管理信息系统模型。