3,707 research outputs found
Modal Logics that Bound the Circumference of Transitive Frames
For each natural number we study the modal logic determined by the class
of transitive Kripke frames in which there are no cycles of length greater than
and no strictly ascending chains. The case is the G\"odel-L\"ob
provability logic. Each logic is axiomatised by adding a single axiom to K4,
and is shown to have the finite model property and be decidable.
We then consider a number of extensions of these logics, including
restricting to reflexive frames to obtain a corresponding sequence of
extensions of S4. When , this gives the famous logic of Grzegorczyk, known
as S4Grz, which is the strongest modal companion to intuitionistic
propositional logic. A topological semantic analysis shows that the -th
member of the sequence of extensions of S4 is the logic of hereditarily
-irresolvable spaces when the modality is interpreted as the
topological closure operation. We also study the definability of this class of
spaces under the interpretation of as the derived set (of limit
points) operation.
The variety of modal algebras validating the -th logic is shown to be
generated by the powerset algebras of the finite frames with cycle length
bounded by . Moreover each algebra in the variety is a model of the
universal theory of the finite ones, and so is embeddable into an ultraproduct
of them
On-line planning and scheduling: an application to controlling modular printers
We present a case study of artificial intelligence techniques applied to the control of production printing equipment. Like many other real-world applications, this complex domain requires high-speed autonomous decision-making and robust continual operation. To our knowledge, this work represents the first successful industrial application of embedded domain-independent temporal planning. Our system handles execution failures and multi-objective preferences. At its heart is an on-line algorithm that combines techniques from state-space planning and partial-order scheduling. We suggest that this general architecture may prove useful in other applications as more intelligent systems operate in continual, on-line settings. Our system has been used to drive several commercial prototypes and has enabled a new product architecture for our industrial partner. When compared with state-of-the-art off-line planners, our system is hundreds of times faster and often finds better plans. Our experience demonstrates that domain-independent AI planning based on heuristic search can flexibly handle time, resources, replanning, and multiple objectives in a high-speed practical application without requiring hand-coded control knowledge
FlowLens: Seeing Beyond the FoV via Flow-guided Clip-Recurrent Transformer
Limited by hardware cost and system size, camera's Field-of-View (FoV) is not
always satisfactory. However, from a spatio-temporal perspective, information
beyond the camera's physical FoV is off-the-shelf and can actually be obtained
"for free" from the past. In this paper, we propose a novel task termed
Beyond-FoV Estimation, aiming to exploit past visual cues and bidirectional
break through the physical FoV of a camera. We put forward a FlowLens
architecture to expand the FoV by achieving feature propagation explicitly by
optical flow and implicitly by a novel clip-recurrent transformer, which has
two appealing features: 1) FlowLens comprises a newly proposed Clip-Recurrent
Hub with 3D-Decoupled Cross Attention (DDCA) to progressively process global
information accumulated in the temporal dimension. 2) A multi-branch Mix Fusion
Feed Forward Network (MixF3N) is integrated to enhance the spatially-precise
flow of local features. To foster training and evaluation, we establish
KITTI360-EX, a dataset for outer- and inner FoV expansion. Extensive
experiments on both video inpainting and beyond-FoV estimation tasks show that
FlowLens achieves state-of-the-art performance. Code will be made publicly
available at https://github.com/MasterHow/FlowLens.Comment: Code will be made publicly available at
https://github.com/MasterHow/FlowLen
Elementary Canonical Formulae: A Survey on Syntactic, Algorithmic, and Modeltheoretic Aspects
In terms of validity in Kripke frames, a modal formula expresses a universal monadic second-order condition. Those modal formulae which are equivalent to first-order conditions are called elementary. Modal formulae which have a certain persistence property which implies their validity in all canonical frames of modal logics axiomatized with them, and therefore their completeness, are called canonical. This is a survey of a recent and ongoing study of the class of elementary and canonical modal formulae. We summarize main ideas and results, and outline further research perspectives
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