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Synthesizing agent protocols from LTL specifications against multiple partially-observable environments
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Synthesizing agent protocols from LTL specifications against multiple partially-observable environments
No full textWe consider the problem of synthesizing an agent protocol satisfying LTL specifications for multiple, partially-observable environments. We present a sound and complete procedure for solving the synthesis problem in this setting and show it is computationally optimal from a theoretical complexity standpoint. While this produces perfect-recall, hence unbounded, strategies we show how to transform these into agent protocols with bounded number of states. Copyright © 2012, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved
Soundness Verification of Data-Aware Process Models with Variable-to-Variable Conditions
No full textTraditionally Business Process Modeling has only focused on the control-flow perspective, thus allowing process designers to specify the constraints on the activities of the process: the order and potential concurrency of their execution, their mutual exclusivity, the possibility of being repeated, etc. However, activities are executed by different resources, manipulate data objects and are constrained by the state of such objects. This requires that the traditional notion of soundness, typically introduced for control-flow-only models, is extended so as to consider data. Intuitively, a (data-aware) process model is sound if (1) it does not contain deadlocks, (2) no more activities are enabled when the process instance is marked as completed and finally (3) there are no parts of the model that cannot be executed. Although several data-aware notations have been introduced in the literature, not all of these are given a formal semantics. In this paper, we propose a technique for checking the data-aware soundness for a specific class of such integrated models, with a simple syntax and semantics, building on Data Petri Nets (DPNs). These are Petri nets enriched with case variables, where transitions are guarded by formulas that inspect and update such variables, and are of the form variable-operator-variable or variable-operator-constant. Even though DPNs are less expressive than Petri nets where data are carried by tokens, they elegantly capture business processes operating over simple case data, allowing to model complex data-aware decisions. We show that, if a DPN is data-aware sound, the Constraint Graph is a finite-state automaton; however, a finite-state Constraint Graph does not guarantee data-aware soundness, but provides a finite structure through which this property can be checked. Finally, we investigate further properties beyond data-aware soundness, such as the problem of verifying that an actor participating in the business process can unilaterally enforce data-aware soundness by restricting the possible executions of a bounded DPN, assuming this actor to be able to control the firing of some transitions and decide the value of some of the case variables whenever these are updated
Supremal realizability of behaviors with uncontrollable exogenous events
No full textThe behavior composition problem involves the automatic synthesis of a controller able to "realize" (i.e., implement) a desired target behavior specification by suitably coordinating a set of already available behaviors. While the problem has been thoroughly studied, one open issue has resisted a principled solution: if the target specification is not fully realizable, is there a way to realize it "at best"? In this paper we answer positively, by showing that there exists a unique supremal realizable target behavior satisfying the specification. More importantly we give an effective procedure to compute such a target. Then, we introduce exogenous events, and show that the supremal can again be computed, though this time, into two variants, depending on the ability to observe such events
Agent composition synthesis based on ATL
No full textAgent, composition is the problem of realizing a "virtual" agent by suitably directing a set of available "concrete", i.e., already implemented, agents. It is a synthesis problem, since its solution amounts to synthesizing a controller that suitably directs the available agents. Agent composition has its roots in certain forms of service composition advocated for SOA, and it has been recently actively studied by AI and Agents community. In this paper, we show that agent composition can be solved by ATL (Alternating-time Temporal Logic) model checking. This results is of interest for at least two contrasting reasons. First, from the point of view of agent composition, it gives access to some of the most modern model checking techniques and state of the art tools, such as MCMAS, that have been recently developed by the Agent community. Second, from the point of view of ATL verification tools, it gives a novel concrete problem to look at, which puts emphasis on actually synthesize winning policies (the controller) instead of just checking that they exist. Copyright © 2010, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved
Two-player game structures for generalized planning and agent composition
No full textIn this paper, we review a series of agent behavior synthesis problems under full observability and nondeter-minism (partial controllability), ranging from conditional planning, to recently introduced agent planning programs, and to sophisticated forms of agent behavior compositions, and show that all of them can be solved by model checking two-player game structures. These structures are akin to transition systems/Kripke structures, usually adopted in model checking, except that they distinguish (and hence allow to separately quantify) between the actions/moves of two antagonistic players. We show that using them we can implement solvers for several agent behavior synthesis problems. Copyright © 2010, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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