115,078 research outputs found
Weighted Linear Dynamic Logic
We introduce a weighted linear dynamic logic (weighted LDL for short) and show the expressive equivalence of its formulas to weighted rational expressions. This adds a new characterization for recognizable series to the fundamental SchĂĽtzenberger theorem. Surprisingly, the equivalence does not require any restriction to our weighted LDL. Our results hold over arbitrary (resp. totally complete) semirings for finite (resp. infinite) words. As a consequence, the equivalence problem for weighted LDL formulas over fields is decidable in doubly exponential time. In contrast to classical logics, we show that our weighted LDL is expressively incomparable to weighted LTL for finite words. We determine a fragment of the weighted LTL such that series over finite and infinite words definable by LTL formulas in this fragment are definable also by weighted LDL formulas
Interaction Graphs: Full Linear Logic
Interaction graphs were introduced as a general, uniform, construction of dynamic models of linear logic, encompassing all Geometry of Interaction (GoI) constructions introduced so far. This series of work was inspired from Girard's hyperfinite GoI, and develops a quantitative approach that should be understood as a dynamic version of weighted relational models. Until now, the interaction graphs framework has been shown to deal with exponentials for the constrained system ELL (Elementary Linear Logic) while keeping its quantitative aspect. Adapting older constructions by Girard, one can clearly define "full" exponentials, but at the cost of these quantitative features. We show here that allowing interpretations of proofs to use continuous (yet finite in a measure-theoretic sense) sets of states, as opposed to earlier Interaction Graphs constructions were these sets of states were discrete (and finite), provides a model for full linear logic with second order quantification
Weighted recognizability over infinite alphabets
We introduce weighted variable automata over infinite alphabets and commutative semirings. We prove that the class of their behaviors is closed under sum, and under scalar, Hadamard, Cauchy, and shuffle products, as well as star operation. Furthermore, we consider rational series over infinite alphabets and we state a Kleene-SchĂĽtzenberger theorem. We introduce a weighted monadic second order logic and a weighted linear dynamic logic over infinite alphabets and investigate their relation to weighted variable automata. An application of our theory, to series over the Boolean semiring, concludes to new results for the class of languages accepted by variable automata
Digital IP Protection Using Threshold Voltage Control
This paper proposes a method to completely hide the functionality of a
digital standard cell. This is accomplished by a differential threshold logic
gate (TLG). A TLG with inputs implements a subset of Boolean functions of
variables that are linear threshold functions. The output of such a gate is
one if and only if an integer weighted linear arithmetic sum of the inputs
equals or exceeds a given integer threshold. We present a novel architecture of
a TLG that not only allows a single TLG to implement a large number of complex
logic functions, which would require multiple levels of logic when implemented
using conventional logic primitives, but also allows the selection of that
subset of functions by assignment of the transistor threshold voltages to the
input transistors. To obfuscate the functionality of the TLG, weights of some
inputs are set to zero by setting their device threshold to be a high .
The threshold voltage of the remaining transistors is set to low to
increase their transconductance. The function of a TLG is not determined by the
cell itself but rather the signals that are connected to its inputs. This makes
it possible to hide the support set of the function by essentially removing
some variable from the support set of the function by selective assignment of
high and low to the input transistors. We describe how a standard cell
library of TLGs can be mixed with conventional standard cells to realize
complex logic circuits, whose function can never be discovered by reverse
engineering. A 32-bit Wallace tree multiplier and a 28-bit 4-tap filter were
synthesized on an ST 65nm process, placed and routed, then simulated including
extracted parastics with and without obfuscation. Both obfuscated designs had
much lower area (25%) and much lower dynamic power (30%) than their
nonobfuscated CMOS counterparts, operating at the same frequency
Bayesian Updating, Model Class Selection and Robust Stochastic Predictions of Structural Response
A fundamental issue when predicting structural response by using mathematical models is how to treat both modeling and excitation uncertainty. A general framework for this is presented which uses probability as a multi-valued
conditional logic for quantitative plausible reasoning in the presence of uncertainty due to incomplete information. The
fundamental probability models that represent the structure’s uncertain behavior are specified by the choice of a stochastic
system model class: a set of input-output probability models for the structure and a prior probability distribution over this set
that quantifies the relative plausibility of each model. A model class can be constructed from a parameterized deterministic
structural model by stochastic embedding utilizing Jaynes’ Principle of Maximum Information Entropy. Robust predictive
analyses use the entire model class with the probabilistic predictions of each model being weighted by its prior probability, or if
structural response data is available, by its posterior probability from Bayes’ Theorem for the model class. Additional robustness
to modeling uncertainty comes from combining the robust predictions of each model class in a set of competing candidates
weighted by the prior or posterior probability of the model class, the latter being computed from Bayes’ Theorem. This higherlevel application of Bayes’ Theorem automatically applies a quantitative Ockham razor that penalizes the data-fit of more
complex model classes that extract more information from the data. Robust predictive analyses involve integrals over highdimensional spaces that usually must be evaluated numerically. Published applications have used Laplace's method of
asymptotic approximation or Markov Chain Monte Carlo algorithms
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