130,285 research outputs found
Interval-based Synthesis
We introduce the synthesis problem for Halpern and Shoham's modal logic of
intervals extended with an equivalence relation over time points, abbreviated
HSeq. In analogy to the case of monadic second-order logic of one successor,
the considered synthesis problem receives as input an HSeq formula phi and a
finite set Sigma of propositional variables and temporal requests, and it
establishes whether or not, for all possible evaluations of elements in Sigma
in every interval structure, there exists an evaluation of the remaining
propositional variables and temporal requests such that the resulting structure
is a model for phi. We focus our attention on decidability of the synthesis
problem for some meaningful fragments of HSeq, whose modalities are drawn from
the set A (meets), Abar (met by), B (begins), Bbar (begun by), interpreted over
finite linear orders and natural numbers. We prove that the fragment ABBbareq
is decidable (non-primitive recursive hard), while the fragment AAbarBBbar
turns out to be undecidable. In addition, we show that even the synthesis
problem for ABBbar becomes undecidable if we replace finite linear orders by
natural numbers.Comment: In Proceedings GandALF 2014, arXiv:1408.556
Observation and Distinction. Representing Information in Infinite Games
We compare two approaches for modelling imperfect information in infinite games by using finite-state automata. The first, more standard approach views information as the result of an observation process driven by a sequential Mealy machine. In contrast, the second approach features indistinguishability relations described by synchronous two-tape automata.
The indistinguishability-relation model turns out to be strictly more expressive than the one based on observations. We present a characterisation of the indistinguishability relations that admit a representation as a finite-state observation function. We show that the characterisation is decidable, and give a procedure to construct a corresponding Mealy machine whenever one exists
RRL: A Rich Representation Language for the Description of Agent Behaviour in NECA
In this paper, we describe the Rich Representation Language (RRL) which is used in the NECA system. The NECA system generates interactions between two or more animated characters. The RRL is a formal framework for representing the information that is exchanged at the interfaces between the various NECA system modules
Supervisor Localization of Discrete-Event Systems based on State Tree Structures
Recently we developed supervisor localization, a top-down approach to
distributed control of discrete-event systems in the Ramadge-Wonham supervisory
control framework. Its essence is the decomposition of monolithic (global)
control action into local control strategies for the individual agents. In this
paper, we establish a counterpart supervisor localization theory in the
framework of State Tree Structures, known to be efficient for control design of
very large systems. In the new framework, we introduce the new concepts of
local state tracker, local control function, and state-based local-global
control equivalence. As before, we prove that the collective localized control
behavior is identical to the monolithic optimal (i.e. maximally permissive) and
nonblocking controlled behavior. In addition, we propose a new and more
efficient localization algorithm which exploits BDD computation. Finally we
demonstrate our localization approach on a model for a complex semiconductor
manufacturing system
Multiport Impedance Quantization
With the increase of complexity and coherence of superconducting systems made
using the principles of circuit quantum electrodynamics, more accurate methods
are needed for the characterization, analysis and optimization of these quantum
processors. Here we introduce a new method of modelling that can be applied to
superconducting structures involving multiple Josephson junctions, high-Q
superconducting cavities, external ports, and voltage sources. Our technique,
an extension of our previous work on single-port structures [1], permits the
derivation of system Hamiltonians that are capable of representing every
feature of the physical system over a wide frequency band and the computation
of T1 times for qubits. We begin with a black box model of the linear and
passive part of the system. Its response is given by its multiport impedance
function Zsim(w), which can be obtained using a finite-element electormagnetics
simulator. The ports of this black box are defined by the terminal pairs of
Josephson junctions, voltage sources, and 50 Ohm connectors to high-frequency
lines. We fit Zsim(w) to a positive-real (PR) multiport impedance matrix Z(s),
a function of the complex Laplace variable s. We then use state-space
techniques to synthesize a finite electric circuit admitting exactly the same
impedance Z(s) across its ports; the PR property ensures the existence of this
finite physical circuit. We compare the performance of state-space algorithms
to classical frequency domain methods, justifying their superiority in
numerical stability. The Hamiltonian of the multiport model circuit is obtained
by using existing lumped element circuit quantization formalisms [2, 3]. Due to
the presence of ideal transformers in the model circuit, these quantization
methods must be extended, requiring the introduction of an extension of the
Kirchhoff voltage and current laws
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