Topic
Operator (computer programming)
About: Operator (computer programming) is a research topic. Over the lifetime, 40896 publications have been published within this topic receiving 671452 citations. The topic is also known as: operator symbol & operator name.
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01 Jan 2003
TL;DR: The Teager Energy Operator as mentioned in this paper is a nonlinear operator defined for both continuous and discrete time signals, which is used for demodulation of AM-FM signals, and how this can be done using the operator and nonlinear methods (Hilberttransform, Prony's, Modified covariance, etc).
Abstract: The Teager Energy Operator is a nonlinear operator defined for both
continuous and discrete time signals. In this thesis we define
different versions and extensions of the one-dimensional operator, and
then look at the properties and positivity of the operator. Its
connection to Volterra systems is explained. The Teager Energy
Operator is used for demodulation of AM-FM signals, and we look at how
this can be done using the operator and nonlinear methods (Hilbert
transform, Prony's, Modified covariance, etc). As the Teager Energy
Operator is sensitive to noise, the multiband demodulation technique
is introduced to refine the estimates. The performance of linear and
nonlinear differentiators is investigated. An application to speech
analysis is shown, using a multiband method to locate formants in
speech. Finally, a performance comparison in different levels of noise
is done.
121 citations
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TL;DR: In this article, a complete set comprising products of single-spin angular momentum operators is introduced as a basis for the expansion of the density operators of typical simple nuclear spin systems encountered in double-resonance high-resolution liquid state nuclear magnetic resonance experiments.
Abstract: The use of a complete set comprising products of single-spin angular momentum operators is introduced as a basis for the expansion of the density operators of typical simple nuclear spin systems encountered in double-resonance high-resolution liquid state nuclear magnetic resonance experiments. Some simple rules are presented for calculating the evolution of the density operator due to arbitrary sequences of unselective radio frequency pulses and periods of free precession due to chemical shifts and scalar couplings. The proportions and nature of the zero-, single- and multiple-quantum order excited by such pulse sequences can readily be predicted, as can the form of the N.M.R. signal itself, when all relaxation effects are neglected. The evolution of some of the basic product operators is interpreted in terms of pictorial models. Some important restrictions on the nature of the states which can be produced by arbitrary pulse sequences are discussed and the possible states of the AX spin system are analys...
121 citations
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03 Jul 1997TL;DR: In this article, the authors define a general additive operator which is able to add traditionally (arithmetic) additive cost factors and which takes into account cost factors which are not additive, the generally additive operator being defined such that distributive and communicative properties are applicable.
Abstract: Connectivity matrix-based multi-cost routing includes defining a generally additive operator which is able to add traditionally (arithmetic) additive cost factors and which takes into account cost factors which are not additive, the generally additive operator being defined such that distributive and communicative properties are applicable, and wherein the generally additive operator is applicable to connectivity matrix-based factors for determining the relative costs of paths within a network, particularly with respect to multi-cost factors. Connectivity matrix-based multi-cost routing is performed by first defining cost functions and establishing a criteria for prioritizing cost functions such that a composite multi-cost function includes the cost functions in the priority order defined by the criterion. A connectivity matrix is established including ordered n-tuples of cost factors corresponding to the priority established by the criterion, and a shortest path matrix determination is made by using the generally additive operator to apply the composite multi-cost function to the connectivity matrix. When links within a network support various functionality, a mask of a required functionality may be used to define a cost function for a given shortest path matrix determination. A correcting method is provided for a routing determination when, after a shortest path matrix determination, a routing choice is not provided which would otherwise satisfy a multi-cost requirement, the correcting method including the determination of a primary path and secondary paths between a source node and a destination node.
121 citations
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TL;DR: In this article, the problem of finding the relation between two operators L1 and L2 of the type we, are dealing with can have identical I-functions was studied.
Abstract: If the operator L is selfadjoint with respect to some reference measure on X , then I ( p ) can be readily computed and formula (1.2) reduces to the classical variational formula for the principal eigenvalue. If L is not selfadjoint, then in general I ( p ) is difficult to evaluate explicitly. In this paper we investigate the situation when X is Rd (it can be replaced by any connected manifold without boundary) and L is an elliptic secondorder differential operator. I ( p ) can be defined as the exact analogue of (1.1) but we need some compactness for (1.2) and therefore we consider the operator L + V only on bounded regions with Dirichlet boundary conditions. After establishing the analogue of (1.2) in such cases, we look at the problem of when two operators L1 and L2 of the type we, are dealing with can have identical I-functions. Equivalently, we seek the relation between L1 and L1 if
121 citations