240 research outputs found
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
Integrating planning and reactive control
Artificial intelligence research on planning is concerned with designing control systems that choose actions by manipulating explicit descriptions of the world state, the goal to be achieved, and the effects of elementary operations available to the system. Because planning shifts much of the burden of reasoning to the machine, it holds great appeal as a high-level programming method. Experience shows, however, that it cannot be used indiscriminately because even moderately rich languages for describing goals, states, and the elementary operators lead to computational inefficiencies that render the approach unsuitable for realistic applications. This inadequacy has spawned a recent wave of research on reactive control or situated activity in which control systems are modeled as reacting directly to the current situation rather than as reasoning about the future effects of alternative action sequences. While this research has confronted the issue of run-time tractability head on, in many cases it has done so by sacrificing the advantages of declarative planning techniques. Ways in which the two approaches can be unified are discussed. The authors begin by modeling reactive control systems as state machines that map a stream of sensory inputs to a stream of control outputs. These machines can be decomposed into two continuously active subsystems: the planner and the execution module. The planner computes a plan, which can be seen as a set of bits that control the behavior of the execution module. An important element of this work is the formulation of a precise semantic interpretation for the inputs and outputs of the planning system. They show that the distinction between planned and reactive behavior is largely in the eye of the beholder: systems that seem to compute explicit plans can be redescribed in situation-action terms and vice versa. They also discuss practical programming techniques that allow the advantages of declarative programming and guaranteed reactive response to be achieved simultaneously
Collected notes from the Benchmarks and Metrics Workshop
In recent years there has been a proliferation of proposals in the artificial intelligence (AI) literature for integrated agent architectures. Each architecture offers an approach to the general problem of constructing an integrated agent. Unfortunately, the ways in which one architecture might be considered better than another are not always clear. There has been a growing realization that many of the positive and negative aspects of an architecture become apparent only when experimental evaluation is performed and that to progress as a discipline, we must develop rigorous experimental methods. In addition to the intrinsic intellectual interest of experimentation, rigorous performance evaluation of systems is also a crucial practical concern to our research sponsors. DARPA, NASA, and AFOSR (among others) are actively searching for better ways of experimentally evaluating alternative approaches to building intelligent agents. One tool for experimental evaluation involves testing systems on benchmark tasks in order to assess their relative performance. As part of a joint DARPA and NASA funded project, NASA-Ames and Teleos Research are carrying out a research effort to establish a set of benchmark tasks and evaluation metrics by which the performance of agent architectures may be determined. As part of this project, we held a workshop on Benchmarks and Metrics at the NASA Ames Research Center on June 25, 1990. The objective of the workshop was to foster early discussion on this important topic. We did not achieve a consensus, nor did we expect to. Collected here is some of the information that was exchanged at the workshop. Given here is an outline of the workshop, a list of the participants, notes taken on the white-board during open discussions, position papers/notes from some participants, and copies of slides used in the presentations
Intelligent Agent Architectures: Reactive Planning Testbed
An Integrated Agent Architecture (IAA) is a framework or paradigm for constructing intelligent agents. Intelligent agents are collections of sensors, computers, and effectors that interact with their environments in real time in goal-directed ways. Because of the complexity involved in designing intelligent agents, it has been found useful to approach the construction of agents with some organizing principle, theory, or paradigm that gives shape to the agent's components and structures their relationships. Given the wide variety of approaches being taken in the field, the question naturally arises: Is there a way to compare and evaluate these approaches? The purpose of the present work is to develop common benchmark tasks and evaluation metrics to which intelligent agents, including complex robotic agents, constructed using various architectural approaches can be subjected
Coordination technology for active support networks: context, needfinding, and design
Coordination is a key problem for addressing goal-action gaps in many human
endeavors. We define interpersonal coordination as a type of communicative
action characterized by low interpersonal belief and goal conflict. Such
situations are particularly well described as having collectively
"intelligent", "common good" solutions, viz., ones that almost everyone would
agree constitute social improvements. Coordination is useful across the
spectrum of interpersonal communication -- from isolated individuals to
organizational teams. Much attention has been paid to coordination in teams and
organizations. In this paper we focus on the looser interpersonal structures we
call active support networks (ASNs), and on technology that meets their needs.
We describe two needfinding investigations focused on social support, which
examined (a) four application areas for improving coordination in ASNs: (i)
academic coaching, (ii) vocational training, (iii) early learning intervention,
and (iv) volunteer coordination; and (b) existing technology relevant to ASNs.
We find a thus-far unmet need for personal task management software that allows
smooth integration with an individual's active support network. Based on
identified needs, we then describe an open architecture for coordination that
has been developed into working software. The design includes a set of
capabilities we call "social prompting," as well as templates for accomplishing
multi-task goals, and an engine that controls coordination in the network. The
resulting tool is currently available and in continuing development. We explain
its use in ASNs with an example. Follow-up studies are underway in which the
technology is being applied in existing support networks.Comment: 16 pages, 4 figures, Scheduled to appear in AI & Society, 33(1), 201
DIALOGIC: A Core Natural-Language Processing System
The DIALOGIC system translates English sentences into representations of their literal meaning in the context of an utterance. These representations, or "logical forms," are intended to be a purely formal language that is as close as possible to the structure of natural language, while providing the semantic compositionality necessary for meaning-dependent computational processing. The design of DIALOGIC (and of its constituent modules) was influenced by the goal of using it as the core language-processing component in a variety of systems, some of which are transportable to new domains of application.Engineering and Applied Science
Bounds on the Cost of Stabilizing a Cooperative Game
This is the author accepted manuscript. The final version is available from the AI Access Foundation via the DOI in this record.A key issue in cooperative game theory is coalitional stability, usually captured by the
notion of the core—the set of outcomes that are resistant to group deviations. However,
some coalitional games have empty cores, and any outcome in such a game is unstable. We
investigate the possibility of stabilizing a coalitional game by using subsidies. We consider
scenarios where an external party that is interested in having the players work together
offers a supplemental payment to the grand coalition, or, more generally, a particular coalition
structure. This payment is conditional on players not deviating from this coalition
structure, and may be divided among the players in any way they wish. We define the
cost of stability as the minimum external payment that stabilizes the game. We provide
tight bounds on the cost of stability, both for games where the coalitional values are nonnegative
(profit-sharing games) and for games where the coalitional values are nonpositive
(cost-sharing games), under natural assumptions on the characteristic function, such as
superadditivity, anonymity, or both. We also investigate the relationship between the cost
of stability and several variants of the least core. Finally, we study the computational
complexity of problems related to the cost of stability, with a focus on weighted voting
games.DFGEuropean Science FoundationNRF (Singapore)European Research CouncilHorizon 2020 European Research Infrastructure projectIsrael Science FoundationIsrael Ministry of Science and TechnologyGoogle Inter-University Center for Electronic Markets and AuctionsEuropean Social Fund (European Commission)Calabria Regio
An Agent Based Approach of Collective Foraging
In this paper the behaviour of a bee colony is modeled as a
society of communicating agents acting in parallel and synchroniz-ing
their behaviour. Two computational models for defining the agents
behaviour are introduced and compared and tools developed for these
models are briefly illustrated.Ministerio de Ciencia y TecnologÃa TIC2002-04220-C03-0
An Agent Architecture for Concurrent Bilateral Negotiations
Abstract. We present an architecture that makes use of symbolic decision-making to support agents participating in concurrent bilateral negotiations. The architecture is a revised version of previous work with the KGP model [23, 12], which we specialise with knowledge about the agent’s self, the negotiation opponents and the environment. Our work combines the specification of domain-independent decision-making with a new protocol for concurrent negotiation that revisits the well-known alternating offers protocol [22]. We show how the decision-making can be specialised to represent the agent’s strategies, utilities and prefer-ences using a Prolog-like meta-program. The work prepares the ground for supporting decision-making in concurrent bilateral negotiations that is more lightweight than previous work and contributes towards a fully developed model of the architecture
Shock-wave thrombus ablation, a new method for noninvasive mechanical thrombolysis
Successful experimental and clinical experience with thrombus ablation has been attained with high-power acoustic energy delivered in a catheter. The goal of this study was to investigate the feasibility of noninvasive thrombus ablation by focused high-power acoustic energy. The source for high-power acoustic energy was a shock-wave generator in a water tank equipped with an acoustic lens with a fixed focal point at 22.5 cm. Thrombus was prepared in vitro, weighed (0.24 +/- 0.08 g), and inserted in excised human femoral artery segments. The arterial segments were ligated, positioned at the focal point and then randomized into either test (n = 8) or control (n = 7). An x-ray system verified the 3-dimensional positioning of the arterial segment at the focal point. A 5 MHz ultrasound imaging system continuously visualized the arterial segment at the focal point before, during and after each experiment. The test segments were exposed to shock waves (1,000 shocks/24 kv). The arterial segment content was then flushed and the residual thrombus weighed. The arterial segment and thrombus were fixed and submitted to histologic examination. The test group achieved a significant ablation of thrombus mass (0.25 +/- 0.15 vs 0.07 +/- 0.003 g; P = 0.0001) after application of shock waves. Arterial segments showed no gross or microscopic damage. Ultrasound imaging revealed a localized (1.9 +/- 0.5 cm2), transient (744 +/- 733 ms), cavitation field at the focal point at the time of application of focused shock waves. Thus, focused high-power acoustic energy can effect noninvasive thrombus ablation without apparent damage to the arterial wall. The mechanism underlying shock-wave thrombus ablation may be associated with the cavitation effect.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29728/1/0000064.pd
- …