Abstract: A machine learning device includes a first acquisition unit, a second acquisition unit, and a learning unit. The first acquisition unit acquires environmental information on a target space. The second acquisition unit acquires number-of-people information indicating a number of people in the target space. The learning unit learns the environmental information acquired by the first acquisition unit and the number-of-people information acquired by the second acquisition unit in association with each other. The environmental information includes an actual carbon dioxide concentration in the target space.

Abstract: A nap environment determination system is configured to determine an environment condition during a nap. The nap environment determination system includes a pre-nap information acquisition unit configured to acquire pre-nap information regarding a subject who takes a nap before the subject takes the nap, and a determination unit configured to determine an environment condition to adjust a sleep depth, based on the pre-nap information.

Abstract: A region recommendation device includes a usage information acquiring unit, an environmental information acquiring unit that acquires environmental information regarding an indoor environment in target regions, a non-environmental information acquiring unit, an information storage unit, and a recommended region determining unit. The usage information acquiring unit acquires usage information including at least one of past usage history of the target regions and current availability of the target regions. The non-environmental information acquiring acquires, as non-environmental information, at least one of biological information of a person in the target space and region feature information regarding equipment and peripheral information in the target regions. The information storage unit stores information acquired by the usage information acquiring unit, the environmental information acquiring unit, and the non-environmental information acquiring unit.

Abstract: A region recommendation device determines one or more recommended regions to be recommended to a target person from a plurality of target regions in a target space. The region recommendation device includes a region information acquiring unit that acquires region information regarding the target regions, a recommended region determining unit that determines the one or more recommended regions based on the region information, and a presenting unit. The presenting unit presents, to the target person, the one or more recommended regions and a recommendation reason used to determine the one or more recommended regions.