A basic agent has been constructed which integrates limited natural language understanding and generation, temporal planning and reasoning, plan execution, simulated symbolic perception, episodic memory, and some general world knowledge. The agent is cast as a robot submarine operating in a two‐dimensional simulated “Seaworld” about which it has only partial knowledge. It can communicate with people in a vocabulary of about 800 common English words using a medium coverage grammar. The agent maintains an episodic memory of events in its life and has a limited ability to reflect on those events. A person can make statements to the agent, ask it questions, and give it commands. In response to commands, a temporal task planner is invoked to synthesize a plan, which is then executed at an appropriate future time. A large variety of temporal references in natural language are interpreted with respect to agent time. The agent can form and retain compound future plans, and replan in response to new information or new commands. Natural language verbs are represented in a state transition semantics for compatibility with the planner. The agent is able to give terse answers to questions about its past experiences, present activities and perceptions, future intentions, and general knowledge. No other artificial intelligence artifact with this range of capabilities has previously been constructed.

A general purpose automated planner/scheduler is described which generates parallel plans to achieve goals with imposed time con-straints. Both durations and start time windows may be specified for sets of goal conditions. The parallel plans consist of not just actions but also of events (triggered by circumstances), inferences, and scheduled events (completely beyond the actor's control). Deterministic dura-tions of all such activities are explicitly modeled, and may be any com-putable function of the activity variables. A start time window for each activity in the plan is updated dynamically during plan generation, in order to maintain consistency with the windows and durations of adja-cent activities and goals. The plans are tailored around scheduled events. The final plan network resembles a PERT chart. From this a schedule of nominal start times for each activity is generated. Ex-amples are drawn from the traditional blocksworld and also from a real-istic ``Spaceworld,'' in which an autonomous spacecraft photographs objects in deep space and transmits the information to Earth. The author is with the Information Systems Research Section, Jet Propulsion Laboratory, Pasadena, CA 91109.

Several topics of theoretical and practical importance to the field of translator writing systems are presented in this paper. These are