# Hierarchy

## The problem of optimality in decision theory and practice

The system aspects of optimality problem within the framework of the structure of decision-making process, connecting it with DM models and tasks, theoretical and practical aspects of optimal solution peculiarity were analyzed. The analysis entropic specification and their impact on the optimal level of practical decisions was made. The DM methods specifications in context of optimal decisions-making were compared, the consumption of partitioning and threshold method, as one of the most flexible for decision-making in different conditions were justified.

## Construction of generalized conclusions by means of linear and nonlinear aggregation methods

The main approaches for the formation of generalized conclusions about operation quality of complex hierarchical network systems are analyzed.  Advantages and drawbacks of the weakest'' element method and a weighted linear aggregation method are determined.  Nonlinear aggregation method is proposed for evaluating the quality of the system, which consists of elements of the same priority.  Hybrid approaches to form generalized conclusions are developed based on the main aggregation methods.  It is shown that they allow us to obtain more reliable generalized conclusions.