SOLUTION OF A WATER RESOURCES PROBLEM WITH ECONOMIES OF SCALE BY LINEAR PROGRAMMING1

ABSTRACT Both because of its effectiveness and ease in use, linear programming has become progressively popular in water resources planning problems. Yet, the assumptions of linear construction costs can be misleading. Diseconomies of scale in construction can be handled by successive approximations to the cost function but problems with economies of scale yield paradoxical results when piecewise approximations are used. If significant economies of scale exist in only one facility, the solution to problems of this nature can be found using normal linear programming codes by successively adjusting the unit construction cost on that single facility to iteratively work toward the true optimal solution.     

FLOOD CONTROL STORAGE ALLOCATIONS BY LINEAR PROGRAMMING1

ABSTRACT. The setting of rule curves for reservoirs or lakes operation requires balancing the flood control storages reserved against the storage requirements for various conservation uses. In this study, a linear programming model is developed to perform single purpose analysis that minimizes flood damages of a multi-lake river system under various initial and input conditions. A flood control utility measure function is arrived from the resulting analysis, and the inclusion of the function in conservation analysis could provide the total functional analysis. The river-system transition function involving time-lags of short duration is described. The function constitutes the basis for the optimization model, and also provides the transformation to reduce significantly the size of the problem. The application to a critical subsystem in the Oswego River System is reported.     

The hotelling valuation of natural resources: some further results

This paper tests the Hotelling Valuation Principle (HVP) for natural resources using data from oil and gas ‘pure plays’ such as royalty trusts and master limited partnerships. The results support the HVP which specifies that the value of any mineral reserve may be predicted by the market price of the resource, net of extraction costs. Regression results also indicate that a Box-Cox transformation of variables provide a better means of estimating the functional relationship between the value of an exhaustible natural resource and its market price.     

成都市春季大气飘尘目标变换因子分析

对成都市大气飘尘（ＳＭＰ〈１０μｍ）用目标变换因子分析（ＴＴＦＡ）作源解析。结果表明，主要排放源及其贡献为，道路交通尘（１６．８％），冶金尘（１９．２％），垃圾与草木焚烧烟尘（２４．８％），燃煤飞灰（５４．３％），大气尘污染以煤烟为主。     

Use of a generalized linear model to evaluate range forage production estimates

Interdisciplinary teams have been used in federal land planning and in the private sector to reach consensus on the environmental impact of management. When a large data base is constructed, verifiability of the accuracy of the coded estimates and the underlying assumptions becomes a problem. A mechanism is provided by the use of a linear statistical model to evaluate production coefficients in terms of errors in coding and underlying assumptions. The technique can be used to evaluate other intuitive models depicting natural resource production in relation to prescribed variables, such as site factors or secondary succession.     

VALUATION OF IMPROVED IRRIGATION EFFICIENCY FROM AN EXHAUSTIBLE GROUNDWATER SOURCE1

This paper presents estimates made via a recursive linear programming model of the net benefits of improving irrigation application efficiency from an exhaustible groundwater source. Net benefits were derived for different application efficiency levels under furrow, sprinkler, and LEPA irrigation systems. In addition, net benefit estimates were obtained for the transition across irrigation systems. Solutions from the model indicate that low crop prices have a differential impact on net benefits across irrigation application efficiencies and irrigation systems. Also, the more limited groundwater situations consistently reduce the economic incentive to adopt improved irrigation application techniques across all irrigation systems.     

OPTIMAL GROUND WATER MANAGEMENT IN TWO-AQUIFER SYSTEMS1

ABSTRACT; This paper presents a numerical model for the prediction of optimal ground water withdrawal from a two-aquifer system by observing a set of constraints determined by the ecological conditions of the ground water basin. The aquifer system consists of an upper unconfined and a lower confined aquifer with a leaky stratum between them. It is assumed that water is withdrawn from the confined aquifer only, but the unconfined aquifer will also be affected due to the leakiness of the layer separating the upper and lower aquifers. Simulation and linear programming are employed for developing a computer model for the optimal management of such systems, with the objectives of determining withdrawal rates for predetermined ground water levels.     

STATISTICAL AND GEOSTATISTICAL MODELLING OF PRELIMINARILY ADJUSTED DEFOLIATION ON AN EUROPEAN SCALE

Since 1987 tree crown condition is surveyed annually in large parts of Europe mainly in terms of defoliation. The plot-wise means of defoliation from 1994 to 2000 were evaluated by General Linear Models (GLM) in order to describe country-specific levels of defoliation and age-trends. Additional runs with estimates for influences of insects and fungi were performed. The amount of variance of defoliation explained by country, age and its interaction was between 35% and 59% for the main tree species, except for Quercus ilex. Additionally, up to 10% could be explained by the inclusion of estimates for infestations by insects and fungi. Residuals of the GLMs were taken as a measure of forest condition not biased by country or age effects and interpreted as preliminarily adjusted defoliation (PAD). PAD values were analysed using geostatistical methods. The modelled spatial autocorrelations were used for kriging. The resulting maps give an overview on regions with elevated defoliation, which may pinpoint regional causes of defoliation. The elimination of methodologically caused variance is a precondition of any cause–effect oriented analyses. The combination of explorative modelling and geostatistics will promote the choice of further promising predictors.     

灰色消解模型的改进——z变换后的线性回归解法

针对文献中提出的灰色消解模型的建模方法进行了ｚ变换，然后改用线性回归的办法求解，实例验证后表明，模拟拟合状况一致，但计算工作量大为减轻。     

线性规划在滇池草海污染目标控制优化决策中的运用

滇池草海污染治理工程是一个复杂的系统，做好规划是保证工程治理效果和有效使用投资的前提。本文将综合治理目标和各决策变量建立函数关系，并将其分析归纳为线性规划问题，根据线性规划的求解原则求出了目标规划的优化方案。