the paper tries to present an improved mathematical model for distribution companies (discos) in order to solve distribution network expansion planning (dnep) problems in the presence of certain resources of distributed generations (dgs) entitled small scale gas engines in the medium voltage grids. with the aim of minimizing investment and operation costs, the recommended model combines a compr...

this research proposes a methodology for ranking decision making units byusing a goal programming model.we suggest a two phases procedure. in phase1, by using some dea problems for each pair of units, we construct a pairwisecomparison matrix. then this matrix is utilized to rank the units via the goalprogramming model.

the helicopter-borne electromagnetic (hem) frequency-domain exploration method is an airborne electromagnetic (aem) technique that is widely used for vast and rough areas for resistivity imaging. the vast amount of digitized data flowing from the hem method requires an efficient and accurate inversion algorithm. generally, the inverse modelling of hem data in the first step requires a precise a...

introduction: this paper proposes an appropriate strategy for exporting hepatitis b vaccine, manufactured by pasteur institute of iran, to other countries. methods: eeffectiveness factors and their relative variables were found out by factor analysis method in spss software. results: we could identify 6 main factors which can extremely affect the export of this product. we evaluated manufacture...

‎In this paper‎, ‎the nonlinear regression models when the model errors follow a slash‎ ‎skew-elliptical distribution‎, ‎are considered‎. ‎In the special case‎ ‎of nonlinear regression models under slash skew-t distribution‎, ‎we‎ ‎present some distributional properties‎, ‎and to estimate their‎ ‎parameters‎, ‎w...

In this research, a novel method to decrease micro-residual stresses of fibrous composites by adding carbon nanotubes (CNTs) is proposed in detail. The negative coefficient of thermal expansion and the high young’s modulus of CNTs can be utilized to counterbalance the process induced residual stresses in composites. To this end, first, the effects of adding CNTs to the matrix of fibrous composi...

nowadays, it’s very usual to use these models in almost all sciences. use of these models has provided quick, appropriate and economic answers to many questions. modeling is developing in different fields of agriculture, including irrigation and drainage. field tests are useful to determine and analyze the different irrigation management but there are significant limitations. the most important...