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In this paper, we introduce the Bodyguard Allocation Problem (BAP) game, that illustrates the behavior of processes with contradictory individual goals in distributed systems. In particular, the game deals with the conflict of interest between two classes of processes that maximize/minimize their distance to a special process called the root. A solution of the BAP game represents a rooted spanning tree in which there exists a condition of equilibrium with maximum social welfare. We analyze the inefficiency of equilibria of the game based on both a completely cooperative and noncooperative approach. Additionally, we design two algorithms, CBAP and DBAP, that provide approximated solutions for the BAP game. We prove that both algorithms always terminate in a configuration with equilibrium and we analyze their running time based on the approach of cooperation used. We perform experimental simulations to compare the overall quality of equilibria obtained by the proposed algorithms. [ABSTRACT FROM AUTHOR]

The performance of processors in a distributed system can be measured by parameters such as bandwidth, storage capacity, work capability, reliability, power limitations, years of usage, among others. Each processor defines its preference based on these parameters. The preference represents an indicator of the quality of service that a processor can provide. An algorithm that follows a preference-based approach uses the preference of the processors to make decisions. In this paper we introduce a randomized self-stabilizing leader election algorithm for preference-based anonymous trees. Our algorithm assures that the processor with the highest preference in the system is always selected as the leader; moreover, it is able to solve symmetric configurations where each preference is the same. We prove that our algorithm has an optimal average time complexity and we also performed simulations to illustrate the average performance of the algorithm. [ABSTRACT FROM AUTHOR]