Maximum entropy method spectral estimation applied to power cable diagnostics via cepstrum processing

The Cepstrum processing method has been used on power cables (1, 2) for determining regions of damage. The method consists of: (1) observing the spectrum of an original broad band signal source, (2) introducing the signal into the cable, (3) computing the change in the observed spectrum (as a result of echos from regions of cable non-uniformity) when the signal is injected into the cable, and finally (4) computing the power-spectrum of the change in observed spectrum. A limitation of this technique is the use of band-limiting spectrum analyzers. Their limited bandwidth reduces range resolution estimation when used with the Fast Fourier Transform (FFT) technique. The maximum entropy method (MEM) is a more useful spectral estimator for this measurement technique. Examples are presented which show a comparison of the FFT and MEM techniques applied to practical cables.     

Essential gyrators and equivalence rules for 3-port function structures

It is shown that a theorem on essential gyrators presented by Rosenberg (1) and used in (2) claims too much and that the internal structure of the multiport elements of the system must be studied in order to be able to decide whether a gyrator is essentially contained in the system or not. Bond graph terminology is used (3)—(6) and a new theorem is formulated, which provides an algorithm to decide on the essentiality of a gyrator by immediate inspection of the bond graph.As a side-result of this approach some new methods for junction structure simplification can be formulated. The significance of junction 3-ports for the concept of the essential gyrator is elaborated by providing equivalence rules for all kinds of junction 3-ports and introducing a unit essential junction 3-port (ES) and a unit non-essential junction 3-port (NES). Finally the hydraulic junction is treated as an example of a physical non-potential junction, i.e. a junction congruent with an ES.     

Study on stability and stabilizability of discrete-time mean-field stochastic systems

This paper is to study the mean square stabilizability and regional stability of discrete-time mean-field stochastic systems. Firstly, a necessary and sufficient condition is presented via the spectrum of linear operator to illustrate the stabilizability of discrete-time mean-field stochastic systems. B(0, γ)-stabilizability is introduced and transformed into solving linear matrix inequalities (LMIs). Secondly, B_M-stability is characterized, especially, the stabilities of circular region, sector region and annulus regions are discussed extensively. Finally, as applications, it is shown that B(0, γ₁; γ₂)-stability has close relationship with the decay rate of the system state response and the Lyapunov exponent.     

Backstepping-based decentralized bounded-H∞ adaptive neural control for a class of large-scale stochastic nonlinear systems

In this paper, a novel decentralized adaptive neural control approach based on the backstepping technique is proposed to design a decentralized H_∞ adaptive neural controller for a class of stochastic large-scale nonlinear systems with external disturbances and unknown nonlinear functions. RBF neural networks are utilized to approximate the packaged unknown nonlinearities. A novel concept with regard to bounded-H_∞ performance is proposed. It can be applied to solve an H_∞ control problem for a class of stochastic nonlinear systems. The constant terms appeared in stability analysis are dealt with by using Gronwall inequality, so that H_∞ performance criterion is satisfied. The assumption that the approximation errors of neural networks must be square-integrable in some literature can be eliminated. The design process for decentralized bounded-H_∞ controllers is given. The proposed control scheme guarantees that all the signals in the resulting closed-loop large-scale system are uniformly ultimately bounded in probability, and each subsystem possesses disturbance attenuation performance for external disturbances. Finally, the simulation results are provided to illustrate the effectiveness and feasibility of the proposed approach.     

Parameter identification of a class of time-varying systems via orthogonal shifted legendre polynomials

A method of using orthogonal shifted Legendre polynomials for identifying the parameters of a process whose behaviour can be modelled by a linear differential equation with time-varying coefficients in the form of finite-order polynomials is presented. It is based on the repeated integration of the differential equation and the representations of $\text{∫}\text{0}\text{t}$s(τ) dτ = Ps(t) and ts(t) = Rs(t), where P and R are constant matrices and s(t) is a shifted Legendre vector whose elements are shifted Legendre polynomials. The differential input-output equation is converted into a set of overdetermined linear algebraic equations for a least squares solution. The results of simulation studies are included to illustrate the applicability of the method.     

Optimal nonuniform distributed networks

Techniques developed in the Sturm—Liouville problem and its Inverse problem are well known in solving the analysis and synthesis problems of non-uniform distributed networks (or NUDN) (1)-(6), (15). However, very few practical results have been obtained from the theory, especially as regards the synthesis part of the problem. In this paper, we show that the chain matrix of an inhomogeneous ladder network (or IHLN) of N sections has undergone exactly the limit process of first-order difference equation approximation of the corresponding differential equation converges to the chain matrix of the corresponding NUDN uniformly on every compact subset of p = z(s)y(s) plane. Therefore an optimal NUDN is proven to be either symmetrical or antimetrical (7). Specifically, a class of optimal NUDN which is optimal on every subinterval of [O,L] has closed-form solutions, and is proven to be both symmetrical and antimetrical.     

Information extraction with automatic knowledge expansion

POSIE (POSTECH Information Extraction System) is an information extraction system which uses multiple learning strategies, i.e., SmL, user-oriented learning, and separate-context learning, in a question answering framework. POSIE replaces laborious annotation with automatic instance extraction by the SmL from structured Web documents, and places the user at the end of the user-oriented learning cycle. Information extraction as question answering simplifies the extraction procedures for a set of slots. We introduce the techniques verified on the question answering framework, such as domain knowledge and instance rules, into an information extraction problem. To incrementally improve extraction performance, a sequence of the user-oriented learning and the separate-context learning produces context rules and generalizes them in both the learning and extraction phases. Experiments on the “continuing education” domain initially show that the F1-measure becomes 0.477 and recall 0.748 with no user training. However, as the size of the training documents grows, the F1-measure reaches beyond 0.75 with recall 0.772. We also obtain F-measure of about 0.9 for five out of seven slots on “job offering” domain.     

Mapping the mix: Linking instruments,settings and target groups in the study of policy mixes

This article proposes the extension of a conceptual framework aimed at analysing policy mixes and their outcomes and demonstrates its value added for the study of sustainability transitions. The argument is that policy mixes research should not focus only on the form of policy instruments, but also on their implementation context. Policy mix form designates the specific policy instruments that are involved according to a policy strategy. Policy mix context includes the specific setting where each policy measure is implemented, such as enterprise or family. It also includes the specific target group of each measure, such as youth or smokers. We apply this conceptual framework to the policy concept and implementation of tobacco control policies in Switzerland, which are an exemplary case for analysing transitions as they are geared towards behavioural change. In a mixed method approach, we triangulate different sets of quantitative and qualitative indicators in order to assess the implementation of eleven subnational policy mixes. Our findings show that taking into account the moderating role of settings between policy instruments and target groups allows for a more in depth analysis of policy processes. Observing the interactions between the four elements policy instruments, policy strategy, the implementation settings and the target groups allows capturing the complexity of policy mixes, at the crossroads of policy design, policy implementation and policy outcomes. Taking implementation settings and target groups into account in the analysis of policy mixes allows for a refined understanding of policy compliance and thus, from a broader perspective, of sustainability transitions.     

Criminal Action Graph: A semantic representation model of judgement documents for legal charge prediction

Semantic information in judgement documents has been an important source in Artificial Intelligence and Law. Sequential representation is the traditional structure for analyzing judgement documents and supporting the legal charge prediction task. The main problem is that it is not effective to represent the criminal semantic information. In this paper, to represent and verify the criminal semantic information such as multi-linked legal features, we propose a novel criminal semantic representation model, which constructs the Criminal Action Graph (CAG) by extracting criminal actions linked in two temporal relationships. Based on the CAG, a Graph Convolutional Network is also adopted as the predictor for legal charge prediction. We evaluate the validity of CAG on the confusing charges which composed of 32,000 judgement documents on five confusing charge sets. The CAG reaches about 88% accuracy averagely, more than 3% over the compared model. The experimental standard deviation also show the stability of our model, which is about 0.0032 on average, nearly 0. The results show the effectiveness of our model for representing and using the semantic information in judgement documents.     

The inverse lure problem of optimal control

Given the linear system $\text{x}\text{}$ = Ax - bu, y = c^Tx, it is shown that, for a certain non-quadratic cost functional, the optimal control is given by u_opt(x) = h(c^Tx), where the function h(y) must satisfy the conditions ky²?h(y)y>0 for y≠0, h(0) = 0 and existence of h^-1 everywhere. The linear system considered must satisfy the Popov condition 1/k + (1 +?ωβ) G(?ω)>0 for all ω, G(s) being the y(s)/u(s) transfer function.     

The representation of radiation reaction in wave mechanics

It is well known that the wave mechanical ψ equation leads to the conclusion that the centroid of the wave mechanical electron should move according to the classical electrodynamic equation of motion in which, however, the terms representing what is commonly called radiation reaction are absent. If v is the velocity of the electron, the classical rate of change of momentum is $\text{md}\text{dt}\text{{}\text{v}\text{(}\text{I}\text{?}\text{v}{}^2\text{c}{}^2\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{}}$. The equation of motion including radiation reaction terms may be regarded as obtainable by replacing this quantity by one obtained by operating upon it with the operator P^?1

$\text{P={I?}\text{α}{}_1\text{kd}\text{dt}\text{+}\text{α}{}_2\text{d}\text{dt}\text{(}\text{kd}\text{dt}\text{)?·}}{}^{\mathrm{?}}$

where α₁, α₂, etc., are constants and $\text{k = (}\text{I}\text{?}\text{v}{}^2\text{c}{}^2\text{)}{}^{\mathrm{<mtext>?1</mtext><mtext>2</mtext>}}$. The main purpose of the paper is to show that if there be any relativistically invariant ψ equation which leads to the classical equation of motion without radiation reaction terms, then by replacing the vector and scalar potentials U and ? in that equation by P(U) and P(?), a relativistically invariant equation of motion will be obtained including the radiation reaction terms, provided that the $\text{d}\text{dt}$ in P be now regarded as $\text{?}\text{?t}$ + u · grad, where u is the velocity of the wave mechanical density distribution at a point. The purpose is to use the power to produce the equation of motion as a criterion for suggesting the proper modification of the ψ equation to apply in those cases where, on the classical theory, the electron would suffer great acceleration, as in ionization by rapidly moving corpuscles.     

Computation of time domain response by numerical inversion of the Laplace transform

A new method for the calculation of time responses of lumped time invariant networks is presented. It is based on the numerical inversion of the Laplace transform and involves the computation of the frequency domain function at pre-assigned complex points and forming a weighted sum. The method exactly inverts a certain number of terms of the Taylor expansion of the time response and is thus equivalent to the methods used for the integration of differential equations. This equivalence is established on two examples. The order of integration can be changed between 1 and 46 without any difficulty. Additional properties resulting from the application of the numerical Laplace transform inversion are also discussed and some novel applications indicated.     

Effects of a magnetic field on the free convective flow through a porous medium bounded by an infinite vertical porous plate with constant heat flux

This paper investigates the effects of a magnetic field on the free convective flow of a viscous, incompressible, dissipative fluid through a porous medium, occupying a semi-infinite region of the space bounded by an infinite vertical and porous plate. The plate is subjected to a normal suction velocity and the heat flux at the plate is constant. The magnetic field is of uniform strength and is applied perpendicular to the plate. An analytical solution to the problem is obtained. The influence of the magnetic parameter (M) and permeability parameter (K) is discussed for the case of air (P = 0.71) when the plate is subjected to a constant suction velocity and is being cooled by free convection currents.     

A VSE equation of state for liquids—II: n-Alkanes,Benzene, Mercury and Water

The work reported in Ref. (1), carried out on n-heptane from 273·16K to the critical point (under moderate pressures), is extended to five n-alkanes, benzene, mercury and water under saturation pressures and extended to much lower temperatures.Forty calculations of various thermodynamic quantities pertaining to the liquids here studied (648 points) are presented in Tables II-IV. All parameters and physical constants involved are presented in Table V. The Standard Percentage Errors (SPE) for all the calculations and the temperature ranges are given in Table VI. The grand average SPE for the 648 points is about one-third of 1%. Only one calculation (the temperature of water from 393·16 to 563·16 K) had an error greater than 1% (18 points).     

Hybrid Analysis of a Large-scale Network by Node-tearing

A new hybrid analysis technique for large-scale networks by node-tearing is presented. The interconnection function matrix is defined and the formulation for computing the transfer function matrix W, the general return difference matrix F_K(X) and the general null return difference matrix F̂_K(X) of a large-scale network is given. In the overall computational process, all the hybrid port parameters are derived from the indefinite-admittance matrix and/or the indefinite-impedance matrix of the component subnetworks.     

Addressing ontology-based question answering with collections of user queries

This paper presents QACID an ontology-based Question Answering system applied to the CInema Domain. This system allows users to retrieve information from formal ontologies by using as input queries formulated in natural language. The original characteristic of QACID is the strategy used to fill the gap between users’ expressiveness and formal knowledge representation. This approach is based on collections of user queries and offers a simple adaptability to deal with multilingual capabilities, inter-domain portability and changes in user information requirements. All these capabilities permit developing Question Answering applications for actual users. This system has been developed and tested on the Spanish language and using an ontology modelling the cinema domain. The performance level achieved enables the use of the system in real environments.     

An application of homomorphic deconvolution to the tomographic restoration of radiographs

This paper derives an optimal homomorphic tomographic filter, to restore tomographic images of blurred radiographs, by taking into account the noise contributed by the other layers. The method is based on the homomorphic deconvolution technique, which is well-known for its performance in image restoration. A computer simulation of the procedure is presented. The results are compared with those obtained by using inverse filtering (3, IEEE Trans on Medical Imaging, Vol. 2, pp. 89–102, 1983) and Wiener filtering (4, Proc. Digitech '84). The paper shows that homomorphic filtering is a suitable and often preferable technique for the tomographic filtering of radiographs.     

On the Generalization of Block Pulse Operational Matrices for Fractional and Operational Calculus

A more rigorous derivation for the generalized block pulse operational matrices is proposed in this paper. The Riemann-Liouville fractional integral for repeated fractional (and operational) integration is integrated exactly, then expanded in block pulse functions to yield the generalized block pulse operational matrices. The generalized block pulse operational matrices perform as s^-α(α\s>;0,α∈R) in the Laplace domain and as fractional (and operational) integrators in the time domain. Also, the generalized block pulse operational matrices of differentiation which correspond to s^α(α\s>;0,α∈R) in the Laplace domain are derived. Based on these results, the inversions of rational and irrational transfer functions are proposed in a simple, accurate and efficient way.     

A new type of wave digital filter

This paper proposes a new wave digital filter derived from doubly terminated LC-ladder networks by replacing each series or shunt arm element of the ladder by its equivalent digital two-port. It is shown that such two-ports may be cascaded without the use of adapters defined by Fettweis (1). A number of realizations of the wave digital two-ports, which are canonic with respect to both multipliers and delays, have been obtained. Also a realization which is canonic with respect to multipliers only is given and an example considered using this realization. The sensitivity of this filter with respect to the multiplier coefficient changes due to finite word length is compared with the conventional cascaded digital filter and also the one proposed by Renner and Gupta. It is found that the proposed filter appears to be a more desirable form of implementation than the conventional cascade form and comparable to that of Renner and Gupta (2).