database_manager

How to use

To start the database_manager ros node, run the following command on terminal -

> rosrun database_manager run_server

Description

To store and manage the facts generated from Spatial and Temporal Reasoning components, and to add a memory to our system, we created a module based on a SQL Temporal Database. Apart from the conceptual perspective taking (as described in belief_manager), another capacity of the database component is the event based time management. This provides memory to the system. When facts are received, the time of detection is present in one of their variables. When the database manager detects a shift in a property, it updates the belief tables as explained in previous section, but it also records the event. To do so, we add a table filled with each event that occurs, recording the time when the property changes. This is a significant component of TOASTER as it is used for testing and debugging this situation assessment framework.

Implementation details

This module continuously reads facts from PDG, area_manager, agent_monitor and move3d_facts. All these facts are updated in the robot's belief state. Once the robot belief state is updated, it updates the other agent's belief state by the idea of conceptual perspective taking.

Inputs

To maintain robot's own belief state, the information produced by perception, geometrical reasoning and inferences are collected by the database management module. Facts computed from area_manger, agent_monitor and move3d_facts are stored in this module.

Outputs

The output of this component is a sql database with fact table and memory table for each agent present in ID table. The fact table stores all the fact true for the agent at that time instant. While, the memory table stores facts that the agent has believed to be true. There is an event table as well to track the occurrence of events like when robot started moving and when it stopped moving. However, during an interaction, many properties that describes an object or an agent may not evolve in time and thus, be considered as static (color, name, age, ownership). To store these static properties, an extra table is present in the database and can be loaded at the start of the interaction, or filled online (if the robot acquire new knowledge on entities). For more details, check https://github.com/Greg8978/toaster/blob/master/database\_manager/doc/database\%20doc.pdf.