Following the concept of ubiquity further on, Ambient Intelligence (AmI) is focused on technologies and approaches for development of intelligent environments aiming at supporting their users. Architectures of these environments are usually modeled by multi-agent systems, facilitating thus investigation of various processes enabling the environments' functionalities. In this scope, it is challenging to study decision processes used by individual components (agents) of the environment in mutual cooperation for creating decisions about ways how and when to support particular users activities adequately. A recent project DE-PIES "Decision Processes in Intelligent Environments", supported by the Czech Scientific Foundation in the period of 2015 to 2017, is oriented on investigation of various decision processes that could appear in various types of intelligent environments, modeled by adequate multi-agent architectures. This paper aims at presenting information about the project goals, its methodology and approaches used as well as intended to be used in near future. A special part of the paper is devoted to possibilities of modeling and simulation of decision processes using the AnyLogic multimethod simulation tool.