Novel operations research methods for efficiently determining irreplaceable sites for conservation

We examine the irreplaceability of sites in the context of the species set covering problem and the maximal covering species problem. We show that a succession of 0-1 programming problems can be solved to quickly determine the set of irreplaceable sites. For the widely available Oregon data set, we find a general lack of trend in the number of irreplaceable sites with the number of sites available for selection used. Moreover, we observe that irreplaceability at one level of resource may not be a predictor of irreplaceability at a higher or a lower level of resource. Finally, we investigate the economic value of irreplaceable sites by trial removals of those sites. This paper is dedicated to the memory of Dr. Charles S. ReVelle.     

城市新经济开发区大气环境容量计算及分配方法研究

随着改革开放步伐的加快，城市开发区也随之蓬勃发展起来。城市新经济开发区的大气环境容量计算及分配是开发区区域环境影响评价的一个重要内容。介绍了建立在网格基础之上的大气污染物总量控制方案的制定方法，引入了污染物扩散转移矩阵概念，并结合广州科学城大气环境总量控制规划，将该方法应用在城市开发区大气环境容量计算及管理中，最后本着公平分配的原则，注重经济效果和社会效率，达到环境保护的目标，提出了一种基于企业占地面积的容量分配方案。按照地块面积划分总量方法不但适应了开发区的动态的发展需要，而且将环境因素引入企业的决策过程。所介绍的方法将对新经济开发区大气环境容量计算及分配具有一定的借鉴作用。     

Modeling methods for managing raw material compositional uncertainty in alloy production

Operational uncertainties create disincentives for use of recycled materials in metal alloy production. One that greatly influences remelter batch optimization is variation in the raw material composition, particularly for secondary materials. Currently, to accommodate compositional variation, firms commonly set production targets well inside the window of compositional specification required for performance reasons. Window narrowing, while effective, does not make use of statistical sampling data, leading to sub-optimal usage of recycled materials. This paper explores the use of a chance-constrained optimization method, which allows explicit consideration of statistical information on composition. The framework and a case study of cast and wrought production with available scrap materials are presented. Results show that it is possible to increase the use of recycled material without compromising the likelihood of batch errors, when using this method compared to conventional window narrowing. This benefit of the chance-constrained method grows with increase in compositional uncertainty and is driven by scrap portfolio diversification.     

Study on the Programming Standard for Ecological Rescue in General Land Use Planning

This paper aims at establishing the operation idea based on the analysis of the connotation,principles and reference indexes for programming standard for ecological rescue.The paper puts forward that the programming standard should take into account the natural,social and economic reference indexes,and modifies the scale and distribution of the ecological rescue according to the order of ecological safety,social safety and economic development.The paper suggests that the land planning department should strengthen the study and datum accumulation in order to establish the technology regulations of programming standard of the ecological rescue.     

Optimizing the horizontal structural diversity in uneven-aged northern hardwood stands

Two mathematical programming formulations are presented which allow the determination of diameter distributions that maximize the diameter class diversity in uneven-aged northern hardwood stands. Distributions generated from these models were found to be comparable from a management standpoint and could be incorporated into existing linear programming models as alternative management scenarios. The models presented here provide an initial framework for quantitatively addressing the requirements of the US National Forest Management Act in matters of diversity in the planning process.     

An interval type-2 fuzzy stochastic approach for regional-scale electric power system under parameter uncertainty

In this study, an interval type-2 fuzzy stochastic linear programming method (IT2FSLP) is developed to support regional-scale electric power system (REM) planning. The IT2FSLP-REM model is based on an integration of interval type-2 fuzzy sets boundary programming and stochastic linear programming techniques enable it to have robust abilities to the deal with uncertainties expressed as type-2 fuzzy intervals and probabilistic distributions within a general optimization framework. Moreover, it can reflect dynamic decisions for energy supply and energy conversion processes, as well as provide capacity expansion options with multiple periods. The developed model is applied to a case of planning regional-scale energy and environmental systems to demonstrate its applicability. Based on a two-step solution algorithm, reasonable solutions have been obtained, which reflect tradeoffs among economic cost, environmental requirements, and energy-supply security. Thus, the lower and upper solutions of IT2FSLP-REM would then help energy authorities adjust or justify allocation patterns of regional energy resources and services.     

A unique intelligent approach for forecasting project completion time in oil refineries

This study presents a hybrid approach for accurate forecasting of project completion time with noisy and uncertain safety factors in oil refineries. The hybrid approach is based on artificial neural network (ANN), fuzzy mathematical programming (FMP) and conventional regression. Three indictors, namely, number of occupational injuries, number of employees and ratio of maximum useful hours over useful hour per month are considered as inputs. Also, project completion time is considered as the main output. To achieve the objective of this study, five sets of data with respect to oil refinery construction projects in various cities of Iran are collected and analyzed through statistical methods. It is shown that for the actual case of this study, ANN presents lowest mean absolute percentage error (MAPE). Also, analysis of variance (ANOVA) is used to verify and validate the results of this study. This is the first study that presents a hybrid approach for accurate estimation and forecasting of project completion time with complex, noisy and uncertain occupational factors.     

The costs of avoiding environmental impacts from shale‐gas surface infrastructure

Growing energy demand has increased the need to manage conflicts between energy production and the environment. As an example, shale‐gas extraction requires substantial surface infrastructure, which fragments habitats, erodes soils, degrades freshwater systems, and displaces rare species. Strategic planning of shale‐gas infrastructure can reduce trade‐offs between economic and environmental objectives, but the specific nature of these trade‐offs is not known. We estimated the cost of avoiding impacts from land‐use change on forests, wetlands, rare species, and streams from shale‐energy development within leaseholds. We created software for optimally siting shale‐gas surface infrastructure to minimize its environmental impacts at reasonable construction cost. We visually assessed sites before infrastructure optimization to test whether such inspection could be used to predict whether impacts could be avoided at the site. On average, up to 38% of aggregate environmental impacts of infrastructure could be avoided for 20% greater development costs by spatially optimizing infrastructure. However, we found trade‐offs between environmental impacts and costs among sites. In visual inspections, we often distinguished between sites that could be developed to avoid impacts at relatively low cost (29%) and those that could not (20%). Reductions in a metric of aggregate environmental impact could be largely attributed to potential displacement of rare species, sedimentation, and forest fragmentation. Planners and regulators can estimate and use heterogeneous trade‐offs among development sites to create industry‐wide improvements in environmental performance and do so at reasonable costs by, for example, leveraging low‐cost avoidance of impacts at some sites to offset others. This could require substantial effort, but the results and software we provide can facilitate the process.