Nickel is ubiquitous in our daily environment and remains the most common cause of contact allergy worldwide. Regulation nickel release exists Europe but unfortunately continues to be absent United States. often associated with earrings other jewelry; however, novel exposures through diet electronic devices materials also occur. Once diagnosed, allergen avoidance key for improvement symptoms.

data envelopment analysis (dea) is a wide range of mathematical models that used for measuring the relative efficiency of a set of harmonic units whit similar inputs and outputs. this model calculates some different weight for input and output variables in each decision making model. this variation in similar weights caused some critiques to this method. from 1991 some linear and nonlinear mode...

in this article, non radial method of dynamic dea with the parallel network structure is presented and is used for calculation of relative efficiency measures when inputs and outputs do not change equally. in this model, dmu divisions under evaluation have been put together in parallel. but its dynamic structure is assumed in series. since in real applications there are undesirable inputs and o...

Data Envelopment Analysis (DEA) deals with evaluating a set of decision-making units (DMUs) based on nonparametric mathematical approaches. In classical DEA models, the given set of factors of DMUs is divided into two categories, inputs and outputs, while in some practical problems there are some measures whose membership to these categories is unclear. It means these factors treat different in...

Long-term strategic investment decisions are associated with high costs and risks. The decision-makers need a solid foundation to judge the best alternative for an project. In every sector of business, taken. natural gas industry in Germany has made considerable expenditures infrastructure will continue future. A part goes into compressor capacity. To avoid misallocation funds optimal compresso...