A content recommendation is provided based on a knowledge graph using, for example, a processor and memory of a device. In some embodiments, sensors are used. The content recommendation efficiently makes user of the processor, memory and/or sensors. A knowledge graph is maintained at the device and another knowledge graph may be maintained at a server. The knowledge graph at the device is generated, for example, by obtaining log history information, generating a device knowledge graph, generating a pattern knowledge graph associated with a behavior pattern of a user, and/or updating the device knowledge graph by adding the pattern knowledge graph to the device knowledge graph. In some examples, the knowledge graph at the server is generated by a server, based on the pattern knowledge graph.