The grey theory is a multidisciplinary and generic theory that deals with systems that lack adequate information and/or have only poor information. In this paper, an improved grey model using step function was propose...The grey theory is a multidisciplinary and generic theory that deals with systems that lack adequate information and/or have only poor information. In this paper, an improved grey model using step function was proposed. Petroleum cost forecast of the Henan oil field was used as the case study to test the efficiency and accuracy of the proposed method. According to the experimental results, the proposed method obviously could improve the prediction accuracy of the original grey model.展开更多
Since 2011 Indonesia has become the world’s largest exporter of steam coal. Two supporting factors of Indonesia to be the largest exporter are its enormous production and low operating cost. This paper foresees the p...Since 2011 Indonesia has become the world’s largest exporter of steam coal. Two supporting factors of Indonesia to be the largest exporter are its enormous production and low operating cost. This paper foresees the production and extraction cost of Indonesian coal in the coming period to evaluate marketing policies and estimate the cost of Indonesian coal supply in domestic market as well as in export market. The production forecasting is carried out by Gompertz curve. Peak production of Indonesian coal is expected to take place in 2026. Moreover, the extraction cost in coal basins which produce high calorific value of coal, in accordance to the operating cost forecasting, is higher than the one with low calorific value of coal due to its higher stripping ratio. Three main basins of Central Sumatra, Tarakan, and Barito basins play major rule in supplying coal for domestic use in short term. And other coal basins such as South Sumatra, Kutai, Bengkulu, and Ombilin basins provide long term supply in the domestic and export markets.展开更多
In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often th...In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often there are few definitions of what is about to be constructed, and frequently not enough to ensure the accuracy of the estimated costs. Considering a global tendency on reducing margins of return over the real estate markets, slight variations of the construction cost can jeopardize the success of the whole real estate enterprise and even the financial stability of the builder or of the developer. This article aims at presenting a method of estimating the building construction costs applicable at the stage of feasibility studies, being able to provide acceptable errors.展开更多
准确预测虚拟电厂辅助调峰成本,可以为制定合理的成本策略、运营管理策略提供依据,达到增强其经济性与市场竞争力的目的。为此,提出基于神经网络的虚拟电厂辅助调峰成本预测方法。分析虚拟电厂辅助调峰成本构成,构建原始数据样本。建立...准确预测虚拟电厂辅助调峰成本,可以为制定合理的成本策略、运营管理策略提供依据,达到增强其经济性与市场竞争力的目的。为此,提出基于神经网络的虚拟电厂辅助调峰成本预测方法。分析虚拟电厂辅助调峰成本构成,构建原始数据样本。建立基于主成分分析嵌入式反向神经网络(principal component analysis-ensemble back propagation,PCA-EBP)的虚拟电厂辅助调峰成本预测模型,利用主成分分析(principal components analysis,PCA)方法去除原始样本中重叠信息,获取有效主成分,重新构建数据样本;将单独的反向传播(back propagation,BP)神经网络视作弱预测器,在Adaboost集成框架下,集成多个BP神经网络,构建预测能力更强的嵌入式反向传播算法(ensemble back propagation,EBP)神经网络,将获得的新数据样本作为EBP神经网络的输入,其输出的结果即为虚拟电厂辅助调峰成本预测结果。实验表明,该方法可以精准预测出虚拟电厂辅助调峰成本,在AUC方面有着较好的表现。展开更多
文摘The grey theory is a multidisciplinary and generic theory that deals with systems that lack adequate information and/or have only poor information. In this paper, an improved grey model using step function was proposed. Petroleum cost forecast of the Henan oil field was used as the case study to test the efficiency and accuracy of the proposed method. According to the experimental results, the proposed method obviously could improve the prediction accuracy of the original grey model.
文摘Since 2011 Indonesia has become the world’s largest exporter of steam coal. Two supporting factors of Indonesia to be the largest exporter are its enormous production and low operating cost. This paper foresees the production and extraction cost of Indonesian coal in the coming period to evaluate marketing policies and estimate the cost of Indonesian coal supply in domestic market as well as in export market. The production forecasting is carried out by Gompertz curve. Peak production of Indonesian coal is expected to take place in 2026. Moreover, the extraction cost in coal basins which produce high calorific value of coal, in accordance to the operating cost forecasting, is higher than the one with low calorific value of coal due to its higher stripping ratio. Three main basins of Central Sumatra, Tarakan, and Barito basins play major rule in supplying coal for domestic use in short term. And other coal basins such as South Sumatra, Kutai, Bengkulu, and Ombilin basins provide long term supply in the domestic and export markets.
文摘In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often there are few definitions of what is about to be constructed, and frequently not enough to ensure the accuracy of the estimated costs. Considering a global tendency on reducing margins of return over the real estate markets, slight variations of the construction cost can jeopardize the success of the whole real estate enterprise and even the financial stability of the builder or of the developer. This article aims at presenting a method of estimating the building construction costs applicable at the stage of feasibility studies, being able to provide acceptable errors.
文摘准确预测虚拟电厂辅助调峰成本,可以为制定合理的成本策略、运营管理策略提供依据,达到增强其经济性与市场竞争力的目的。为此,提出基于神经网络的虚拟电厂辅助调峰成本预测方法。分析虚拟电厂辅助调峰成本构成,构建原始数据样本。建立基于主成分分析嵌入式反向神经网络(principal component analysis-ensemble back propagation,PCA-EBP)的虚拟电厂辅助调峰成本预测模型,利用主成分分析(principal components analysis,PCA)方法去除原始样本中重叠信息,获取有效主成分,重新构建数据样本;将单独的反向传播(back propagation,BP)神经网络视作弱预测器,在Adaboost集成框架下,集成多个BP神经网络,构建预测能力更强的嵌入式反向传播算法(ensemble back propagation,EBP)神经网络,将获得的新数据样本作为EBP神经网络的输入,其输出的结果即为虚拟电厂辅助调峰成本预测结果。实验表明,该方法可以精准预测出虚拟电厂辅助调峰成本,在AUC方面有着较好的表现。
