Multi-agent planning and scheduling, execution monitoring and incremental rescheduling: Application to motorway traffic

This article describes a planning method applicable to agents with great perception and decision-making capabilities and the ability to communicate with other agents. Each agent has a task to fulfill allowing for the actions of other agents in its vicinity. Certain simultaneous actions may cause conflicts because they require the same resource. The agent plans each of its actions and simultaneously transmits these to its neighbors. In a similar way, it receives plans from the other agents and must take account of these plans. The planning method allows us to build a distributed scheduling system. Here, these agents are robot vehicles on a highway communicating by radio. In this environment, conflicts between agents concern the allocation of space in time and are connected with the inertia of the vehicles. Each vehicle made a temporal, spatial, and situated reasoning in order to drive without collision. The flexibility and reactivity of the method presented here allows the agent to generate its plan based on assumptions concerning the other agents and then check these assumptions progressively as plans are received from the other agents. A multi-agent execution monitoring of these plans can be done, using data generated during planning and the multi-agent decision-making algorithm described here. A selective backtrack allows us to perform incremental rescheduling

On Being Responsible

Joint responsibility is a mental and behavioural state which captures and formalizes many of the intuitive underpinnings of collaborative problem solving. It defines the pre-conditions which must hold before such activity can commence, how individuals should behave (in their own problem solving and towards others) once such problem solving has begun and minimum conditions which group participants must satisfy

Reasonable Goals

Assume that a number of autonomous agents are going to act in such a way that their respective goal states constitute a global plan. A main question that arises in this situation is whether there is such a plan at all, i.e. whether a solvable conflict prevails. In some sense. this means that the set of common goals is non-empty. Furthermore, if the agents are allowed to act in accordance with the result of some decision process, a situation may occur where subsets of their possible goal sets are consistent, but in actual fact the individual agents may nevertheless always terminate in states that are in conflict. We present a formal framework for the analysis of conflicts in sets of autonomous agents restricted in the sense that they can be described in a (first-order) language and by a transaction mechanism. This is also enriched by processes for evaluating decision situations given imprecise background information. The agent specifications are analysed with respect to a concept of consistency that requires the formulae of one specification together with a set of correspondence assertions to not restrict the models of another specification. i.e. the agent system does not essentially restrict the individual agents. The main emphasis is on the specifications being compatible with respect to reasonable probable states. i.e. states for which it is reasonable to assume that they eventually will be reached

Merging plans with incomplete knowledge about actions and goals through an agent-based reputation system

Managing transition plans is one of the major problems of people with cognitive disabilities. Therefore, finding an automated way to generate such plans would be a helpful tool for this community. In this paper we have specifically proposed and compared different alternative ways to merge plans formed by sequences of actions of unknown similarities between goals and actions executed by several operator agents which cooperate between them applying such actions over some passive elements (node agents) that require additional executions of another plan after some time of use. Such ignorance of the similarities between plan actions and goals would justify the use of a distributed recommendation system that would provide an useful plan to be applied for a certain goal to a given operator agent, generated from the known results of previous executions of different plans by other operator agents. Here we provide the general framework of execution (agent system), and the different merging algorithms applied to this problem. The proposed agent system would act as an useful cognitive assistant for people with intelectual disabilities such as autism

Merging plans with incomplete knowledge about actions and goals through an agent-based reputation system

In This Paper, We Propose And Compare Alternative Ways To Merge Plans Formed Of Sequences Of Actions With Unknown Similarities Between The Goals And Actions. Plans Are Formed Of Actions And Are Executed By Several Operator Agents, Which Cooperate Through Recommendations. The Operator Agents Apply The Plan Actions To Passive Elements (Which We Call Node Agents) That Will Require Additional Future Executions Of Other Plans After Some Time. The Ignorance Of The Similarities Between The Plan Actions And The Goals Justifies The Use Of A Distributed Recommendation System To Produce A Useful Plan For A Given Operator Agent To Apply Towards A Certain Goal. This Plan Is Generated From The Known Results Of Previous Executions Of Various Plans By Other Operator Agents. Here, We Present The General Framework Of Execution (The Agent System) And The Results Of Applying Various Merging Algorithms To This Problem.This work was supported in part by Project MINECO TEC2017-88048-C2-2-

The problem with multiple robots

The issues that can arise in research associated with multiple, robotic agents are discussed. Two particular multi-robot projects are presented as examples. This paper was written in the hope that it might ease the transition from single to multiple robot research

Mechanisms for Automated Negotiation in State Oriented Domains

This paper lays part of the groundwork for a domain theory of negotiation, that is, a way of classifying interactions so that it is clear, given a domain, which negotiation mechanisms and strategies are appropriate. We define State Oriented Domains, a general category of interaction. Necessary and sufficient conditions for cooperation are outlined. We use the notion of worth in an altered definition of utility, thus enabling agreements in a wider class of joint-goal reachable situations. An approach is offered for conflict resolution, and it is shown that even in a conflict situation, partial cooperative steps can be taken by interacting agents (that is, agents in fundamental conflict might still agree to cooperate up to a certain point). A Unified Negotiation Protocol (UNP) is developed that can be used in all types of encounters. It is shown that in certain borderline cooperative situations, a partial cooperative agreement (i.e., one that does not achieve all agents' goals) might be preferred by all agents, even though there exists a rational agreement that would achieve all their goals. Finally, we analyze cases where agents have incomplete information on the goals and worth of other agents. First we consider the case where agents' goals are private information, and we analyze what goal declaration strategies the agents might adopt to increase their utility. Then, we consider the situation where the agents' goals (and therefore stand-alone costs) are common knowledge, but the worth they attach to their goals is private information. We introduce two mechanisms, one 'strict', the other 'tolerant', and analyze their affects on the stability and efficiency of negotiation outcomes.Comment: See http://www.jair.org/ for any accompanying file

Working Notes from the 1992 AAAI Spring Symposium on Practical Approaches to Scheduling and Planning

The symposium presented issues involved in the development of scheduling systems that can deal with resource and time limitations. To qualify, a system must be implemented and tested to some degree on non-trivial problems (ideally, on real-world problems). However, a system need not be fully deployed to qualify. Systems that schedule actions in terms of metric time constraints typically represent and reason about an external numeric clock or calendar and can be contrasted with those systems that represent time purely symbolically. The following topics are discussed: integrating planning and scheduling; integrating symbolic goals and numerical utilities; managing uncertainty; incremental rescheduling; managing limited computation time; anytime scheduling and planning algorithms, systems; dependency analysis and schedule reuse; management of schedule and plan execution; and incorporation of discrete event techniques

Contracting Tasks in Multi-Agent Environments

Agents may contract some of their tasks to other agent even when they do not share a common goal. An agent may try to contract some of the tasks that it cannot perform by itself, or that may be performed more efficiently by other agents. One self-motivated agent may convince another self-motivated agent to help it with its task, by promises of rewards, even if the agents are not assumed to be benevolent. We propose techniques that provide efficient ways to reach contracting in varied situations: the agents have full information about the environment and each other or subcontracting when the agents do not know the exact state of the world. We consider situations of repeated encounters, cases of asymmetric information, situations where the agents lack information about each other, and cases where an agent subcontracts a task to a group of agents. Situations where there is competition among possible contracted agents or possible contracting agents are also considered. In all situations we would like the contracted agent to carry out the task efficiently without the need of close supervision by the contracting agent. (Also cross-referenced as UMIACS-TR-94-44