Data Envelopment Analysis (DEA) and Ratio Analysis (RA) are two widely used methods for measuring units' productivity and any other criteria that could be assessed based on the available input and output variables. A number of researchers have studied DEA and RA and noted the positive and negative differences between them. Aggregated ratio analysis (ARA) model, which provide an important linkage between DEA and RA theory, is equivalent to the CCR DEA model, and this equivalence property offers a great deal of opportunities for DEA to be interpreted and applied in different ways. This paper extends the results of ARA model and proposes an extended aggregated ratio analysis (EARA) model, similar as the development from CCR model to BCC model in DEA context. The proposed model can offer an insight into the characteristic of returns to scale, playing the corresponding role as BCC model does. The numerical example is revisited in the paper and the results are compared....
Stamping process, which is widely used in automobile, aerospace, machine-building industries, and etc., is a creative process needing time and experiences. The lead time is mainly spent on stamping die design and manufacturing. As the basis of die design, process design is a non-linearity and creative process, which can be solved by using the fuzzy synthetic evaluation. In this paper, the potential of fuzzy synthetic evaluation for dealing with stamping process design was explored. The influencing factor set, factor weight set, evaluation set, single factor fuzzy evaluation matrix, and fuzzy synthetic evaluation scheme were studied. Finally, the washer part, considering forming equipment, part dimensions and other factors, was selected to testify the evaluation process....
Stability condition and quality evaluation formula of layerlike backfilling roof, Q≥C, where Q denotes is quality index depending on allowable compressive or tensile strength and integrity of backfilling, and C is the technical index depending on mining method and backfilling technology, were inferred according to simply supported beam theorem. Technical treatment measures for instable backfilling roof, including optimum of appropriate filling materials and dosage for excellent flow property and reduction of backfill cost. It is proved that slope equation of backfill slurry in a stope to be filled is y=hexp[-x2/(2σ)2)], where h is height of cone and σ2 is mean square, and that optimum drainage point of backfill slurry can be determined by the equation and sizes of stope. Case study indicates that the results can give a theoretical support for quality evaluation and control of layerlike backfilling....
Hydrocarbon generating and expulsion simulation experiments are carried out using samples artifically matched between the acid-dissolved residue of relatively low-maturity limestone and the original sample. This work makes up for the insufficiency of source rock samples with high abundance of organic matters and low maturity in China. The organic carbon content of the 10 prepared samples varies between 0.15 % and 0.74 %. Pyrolysis data and simulation experiment results of hydrocarbon generating and expulsion, which were obtained by a high-temperature and high-pressure open system, indicate that the lower limit of organic carbon content for marine carbonate rock to generate and expel hydrocarbons is 0.23 %-0.31%. In combination with the numerical analysis of organic carbon in marine carbonate rocks from Tarim Basin, Sichuan Basin, Ordos Basin and North China, as well as the contribution of these gas source rocks to the discovered gas pools, we think that the organic carbon criterion for carbonate gas source rocks should be 0.3%....
The uniqueness of shale gas plays is contrasted with conventional oil and gas exploration. Based on our ten year history in shale gas exploration, a practical 17 point list of criteria to use for screening shale gas projects and ranking that encompasses geoscience, geochemistry, reservoir engineering, drilling, completions and production operations is developed and explained. Other considerations that will impact shale gas development are identified and discussed. Some key methodologies to incorporate in the evaluation process are also proposed. The outcome of this proposed screening process, if rigorously applied,should quickly identify the projects that have the most likely chance for success for recommendation to management. Examples from active shale gas plays in the United States are used to support these criteria and references to relevant recent publications and presentations are provided....
How to accurately recover the hydrocarbon loss is a crucial step in reservoir evaluation by Rock-Eval pyrolysis. However, it is very difficult to determine the recovering coefficients because there are numerous factors causing the hydrocarbon loss. Aiming at this problem, a new method named critical point analysis is put forward in this paper. The first step of the method is to find the critical point by drawing the scatterplot of hydrocarbon contents versus the ratio of the light component of with the heavy component of;And the second step is to calculate the recovering coefficient by contrasting the pyrolysis parameters at the critical point of different sample types. This method is not only been explained reasonably theoretically,but also has got a good application effect in Huanghua depression....
The conditions for the positive operation of water conservancy projects are described in this paper. A scientific and effective evaluation index system was established based on frequency analysis, theoretical analysis, and expert consultation. This evaluation index system can be divided into six first-level indices: the degree to which facilities are intact and functionality standards are reached, the status of operation and management funds, the rationality and degree of advancement of the management team structure, the adaptability and rationality of the water conservancy project management system, the degree of automatization and informationization of the management techniques, and the conduciveness of the exterior environment. The weights for evaluation indices were obtained through the analytic hierarchy process method with consideration of the difference between public welfare and profit-oriented water conservancy projects. This study provides a scientific method for evaluating the positive operation of water conservancy projects....
Taking Tibet as an example, the functional essentiality degrees of water resources conserving of regions were discussed in this paper. At first, based on the status of regional vegetation, whether the region has the function of water conserving was made certain. And then, according to the impacted objects of water resources conserving, taking into account the demands for water and regional supply capacities of water and the requirement of environmental protection, the functional grades of regional water resources conserving of Tibet were evaluated in this paper....
In order to understand the dynamic change of water quality in a specific period of time,a type of possibility transition matrix based on the theory of Markov process was established.The transition possibility with a weight to calculate the degree of absolute advancement was given based on the result of water quality evaluation,the concept of relative advancement was presented.It was used to evaluate the extent of water quality changed in a period of time.The method was used to calculate the degrees of relative advancement for 4 rivers in China,and the results were analyzed....
Rope shovels are used to dig and load materials in surface mines. One of the main factors that influence the production rate and energy consumption of rope shovels is the performance of the operator. This paper presents a method for evaluating rope shovel operators using the Multi-Attribute Decision-Making (MADM) model. Data used in this research were collected from an operating surface coal mine in the southern United States. The MADM model consists of attributes, their weights of importance, and alter-natives. Shovel operators are considered the alternatives. The energy consumption model was developed with multiple regression analysis, and its variables were included in the MADM model as attributes. Preferences with respect to min/max of the defined attributes were obtained with multi-objective opti-mization. Multi-objective optimization was conducted with the overall goal of minimizing energy con-sumption and maximizing production rate. Weights of importance of the attributes were determined by the Analytical Hierarchy Process (AHP). The overall evaluation of operators was performed by one of the MADM models, i.e., PROMETHEE II. The research results presented here may be used by mining professionals to help evaluate the performance of rope shovel operators in surface mining....
