Click here for the derivation of the solution to the Sussman Anomaly.
SIPE-2: System for Interactive Planning and Execution
AI Center ,
See a 7-minute video, recorded in 2013, giving a
historical overview of the SIPE HTN planning system (expand window to be at least 1280x720).
The key features of the SIPE-2 plan-generation technology are:
Artificial Intelligence (AI) planning techniques developed over the
past three decades at the AI Center of SRI International have now reached the point where they
can impact real problems. SIPE-2 is the most advanced of SRI's plan
generation and execution systems, and has been employed by numerous
users to solve a range of interesting problems, as described above.
It is the planner in the Cypress and CPEF systems
and is used in the Multiagent Planning Architecture.
- Efficiently reasons about actions to generate a novel sequence of actions that responds precisely to the situation at hand
- Supports interactive planning, allowing humans and the system to cooperate in mixed-initiative planning
- Supports the giving of advice to the planner
- Plans hierarchically at different levels of abstraction
- Is domain-independent (multiuse)
- Replans during execution
- Generates parallel plans (allowing multiple agents)
- Posts constraints and reasons about resources
- Interacts with humans through a powerful graphical interface
SIPE-2 is a performance-oriented, general-purpose software system for
generating and monitoring the execution of plans. It plans hierarchically,
using different levels of abstraction, and provides a formalism for
describing actions as operators. Given an arbitrary initial situation
and a set of goals, SIPE-2 either automatically or under interactive control
combines operators to generate plans to achieve the prescribed goals in the
given world. In contrast to most AI planning research, heuristic adequacy
(efficiency) has been one of the primary goals in the design of SIPE-2, which
includes many heuristics for reducing computational complexity. Unlike
expert systems, the SIPE-2 architecture is
capable of generating a novel sequence of actions that responds precisely to
the situation at hand.
Planning requires the system to predict how the world will change as
actions are performed. However, in real-world domains, things do not
always proceed as planned and it becomes increasingly important to use
as much as possible of the old plan when new situations arise. SIPE-2
has execution-monitoring techniques that accept new information about
the world and modify the plan minimally to respond to unexpected events.
In practical applications, natural pictorial representations are
necessary for a human user to understand the domain knowledge, the
plan, the planning process, and the execution of the plan. SIPE-2
provides a powerful graphical user interface (built on
The image at the top of this page is a pictorial
representation of a plan drawn by SIPE-2. Graphical tools can be
used for the following purposes:
SIPE-2 incorporates the
Advisable Planner. The Advisable Planner enables users to direct the
planning process in a more powerful and general manner, through the provision
of high-level guidance that influences the nature of the solutions generated.
Advice consists of task-specific properties of both the desired solution and
the problem-solving process to be used for a particular problem. Advice is
an adjunct to the domain knowledge that underlies a given planning
- inputting domain knowledge and creating operators
- following and controlling the planning process
- viewing complex information (including plans, operators, and
world descriptions) as graphs on the screen
SIPE-2 uses Tachyon for temporal reasoning.
SIPE-2 and Grasper-CL are trademarks of SRI International.
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Dr. David E. Wilkins
Last modified: Wed May 24 14:59:58 2000