为解决这一问题，研究了灰色组合模型在发动机研制费用估算中的应用。

This paper suggests Gray combined Model should be used in estimating the Engine Development Cost so as to solve the problem mentioned above.

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针对每个阶段的不同特点和要求，分析了该阶段的费用构成，并采用相应的方法建立了各自的估算模型。

And then according to the different characteristics and requirements of each phase, it analyzes the cost composing of this phase and establishes the estimating model respectively.

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分析了影响土地成本费用的主要因素，提出了控制的主要措施、地价的测算模型和土地费用估算方法。

Analysis the main factors about land cost influence, and provides the main control measures. Put forwards the price model about land calculation, and estimates the land cost.

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