The system identification and control of Hammerstein system using non-uniform rational B-spline neural network and particle swarm optimization

In this paper a new system identification algorithm is introduced for Hammerstein systems based on observational input/output data. The nonlinear static function in the Hammerstein system is modelled using a non-uniform rational B-spline (NURB) neural network. The proposed system identification algorithm for this NURB network based Hammerstein system consists of two successive stages. First the shaping parameters in NURB network are estimated using a particle swarm optimization (PSO) procedure. Then the remaining parameters are estimated by the method of the singular value decomposition (SVD). Numerical examples including a model based controller are utilized to demonstrate the efficacy of the proposed approach. The controller consists of computing the inverse of the nonlinear static function approximated by NURB network, followed by a linear pole assignment controller.

On the entrainment assumption in Schatzmann's integral plume model

The behaviour of stationary, non-passive plumes can be simulated in a reasonably simple and accurate way by integral models. One of the key requirements of these models, but also one of their less well-founded aspects, is the entrainment assumption, which parameterizes turbulent mixing between the plume and the environment. The entrainment assumption developed by Schatzmann and adjusted to a set of experimental results requires four constants and an ad hoc hypothesis to eliminate undesirable terms. With this assumption, Schatzmann’s model exhibits numerical instability for certain cases of plumes with small velocity excesses, due to very fast radius growth. The purpose of this paper is to present an alternative entrainment assumption based on a first-order turbulence closure, which only requires two adjustable constants and seems to solve this problem. The asymptotic behaviour of the new formulation is studied and compared to previous ones. The validation tests presented by Schatzmann are repeated and it is found that the new formulation not only eliminates numerical instability but also predicts more plausible growth rates for jets in co-flowing streams.

A fast two-grid and finite section method for a class of integral equations on the real line with application to an acoustic scattering problem in the half-plane

We consider the numerical treatment of second kind integral equations on the real line of the form ∅(s) = ∫_(-∞)^(+∞)▒〖κ(s-t)z(t)ϕ(t)dt,s=R〗 (abbreviated ϕ= ψ+K_z ϕ) in which K ϵ L_1 (R), z ϵ L_∞ (R) and ψ ϵ BC(R), the space of bounded continuous functions on R, are assumed known and ϕ ϵ BC(R) is to be determined. We first derive sharp error estimates for the finite section approximation (reducing the range of integration to [-A, A]) via bounds on (1-K_z )^(-1)as an operator on spaces of weighted continuous functions. Numerical solution by a simple discrete collocation method on a uniform grid on R is then analysed: in the case when z is compactly supported this leads to a coefficient matrix which allows a rapid matrix-vector multiply via the FFT. To utilise this possibility we propose a modified two-grid iteration, a feature of which is that the coarse grid matrix is approximated by a banded matrix, and analyse convergence and computational cost. In cases where z is not compactly supported a combined finite section and two-grid algorithm can be applied and we extend the analysis to this case. As an application we consider acoustic scattering in the half-plane with a Robin or impedance boundary condition which we formulate as a boundary integral equation of the class studied. Our final result is that if z (related to the boundary impedance in the application) takes values in an appropriate compact subset Q of the complex plane, then the difference between ϕ(s)and its finite section approximation computed numerically using the iterative scheme proposed is ≤C_1 [kh log⁡〖(1⁄kh)+(1-Θ)^((-1)⁄2) (kA)^((-1)⁄2) 〗 ] in the interval [-ΘA,ΘA](Θ<1) for kh sufficiently small, where k is the wavenumber and h the grid spacing. Moreover this numerical approximation can be computed in ≤C_2 N log⁡N operations, where N = 2A/h is the number of degrees of freedom. The values of the constants C1 and C2 depend only on the set Q and not on the wavenumber k or the support of z.

Solvability and spectral properties of integral equations on the real line: I. Weighted spaces of continuous functions

We consider in this paper the solvability of linear integral equations on the real line, in operator form (λ−K)φ=ψ, where and K is an integral operator. We impose conditions on the kernel, k, of K which ensure that K is bounded as an operator on . Let Xa denote the weighted space as |s|→∞}. Our first result is that if, additionally, |k(s,t)|⩽κ(s−t), with and κ(s)=O(|s|−b) as |s|→∞, for some b>1, then the spectrum of K is the same on Xa as on X, for 01. As an example where kernels of this latter form occur we discuss a boundary integral equation formulation of an impedance boundary value problem for the Helmholtz equation in a half-plane.

Whistle-blowing by external auditors: seeking legitimacy for the South African audit profession?

Auditing is often cited as playing an important role in managing agency-related costs and, accordingly, being integral to the sound functioning of capital markets. There may, however, be more to the attest function than a technical rational practice. By virtue of relying heavily on claims to technical expertise, professionalism, prudential judgement and public confidence, auditing is both a source of legitimacy for organisations and, paradoxically, dependent on claims to legitimacy for its continued existence. From this perspective, recent regulatory developments, purportedly enacted to increase arms-length control over the profession, may not only be about improving perceived audit quality and practice but also about ensuring continued faith in the well-established ‘rituals’ of the assurance function. A reporting duty imposed on South African external auditors, akin to whistle-blowing, is used as a case study to explore this perspective. In doing so, this paper contributes to the scant body of interpretive research on auditing, simultaneously offering one of the first insights into auditing regulation from an African perspective.

From Rational Design of Drug Crystals to Understanding of Nucleic Acid Structures: Lamivudine Duplex

A DNA-like duplex of nucleosides is probable to exist even without the 5`-phosphate groups needed to assemble the chain backbone. However, double-stranded helical structures of nucleosides are unknown. Here, we report a duplex of nucleoside analogs that is spontaneously assembled due to stacking of the neutral and protonated molecules of lamivudine, a nucleoside reverse transcriptase inhibitor (NTRI) widely used in anti-HIV drug combinatory medication. The left-handed lamivudine duplex has features similar to those of i-motif DNA, as the face-to-face base stacking and the helix rise per base pair. Furthermore, the protonation pattern on alternate bases expected for it DNA-like duplex stabilized by pairing of neutral and protonated cytosine fragments was observed for the first time in the lamivudine double-stranded helix. This structure demonstrates that hydrogen bonds can substitute for covalent phosphodiester linkage in the stabilization of the duplex backbone. This interesting example of spontaneous molecular self-organization indicates that the 5`-phosphate group could not be a requirement for duplex assembly.

A case for a revival of tonic sol-fa in the twenty-first century

The Tonic Sol-fa method of teaching singing was developed in England by John Curwen over a period of forty years from the 1840s until the 1870s. Although originally an aid to reading staff notation, the J 872 Standard Course saw staff notation dispensed with altogether in favour of its own notational system. By the end of the century it had spread from Britain to Australia, New Zealand, South Africa, Canada, the United States, India, China, Japan and the Pacific Islands. However, largely due to its notational isolation, Tonic Sol-fa declined markedly during the early twentieth century. Except for the incorporation of certain aspects into the Kodaly method, it has largely disappeared from contemporary music teaching practice. Surprisingly, however, Tonic Sol-fa in its nineteenth century form is presently "alive and well" in certain developing countries in Africa, Asia and the Pacific. This paper will present an analysis of Tonic Sol-fa and evaluate its characteristics in terms of contemporary pedagogical and notational theory. The paper will then report on the current use of Tonic Sol-fa in developing countries and it will be argued that, in certain of these countries, this nineteenth century teaching method and notational system has not only survived but has indeed flourished. It will be argued that, in at least one case, Tonic Sol-fa has been "indiginised" so that it has not only become an integral part of the musical culture but also has become part of the social fabric of the country. The case will be put for a revival of Tonic Sol-fa in developing countries where, for social, economic and educational reasons, an alternative model to that utilised in more highly developed countries may be more successful/ in promoting school and community choral music.

Integral terminal sliding mode cooperative control of multi-robot networks

This paper studies the integral terminal sliding mode cooperative control of multi-robot networks. Here, we first propose an integral terminal sliding mode surface for a class of first order systems. Then, we prove that finite time consensus tracking of multi-robot networks can be achieved on this integral terminal sliding mode surface. Simulation results are presented to validate the analysis.

Functionalism, co-operation, good faith, and the making of the "daily-preventive justice" in contract law theory and practice. A contribution to a rational understanding of good faith and to its future reseasonable developments. Evaluations from

The thoughts and observations contained in this paper were first presented in a preliminary form at the Staff Seminar that I gave at the University of Cape Town (UCT) - Department of Private Law, on Tuesday May 8 2012. The organizers generously offered me a free choice of subject. Such an offer always poses a problem to imaginative people like myself. I finally chose as my subject the role of good faith in contract law theory and practice and then entitled the Seminar “Good Faith & Contracts - Brothers in Arms”. The aim of the talk was to briefly describe what I see behind the doctrine of good faith (and, more broadly, behind the general course of the parties’ behavior before and after the conclusion of an agreement), to then explain the need of its protection and future reasonable developments by challenging the limitations of both traditional and current legal approaches to contract law theory and practice. By adopting a comparative modus investigandi, it emerged that especially in the area of contract law a new law-finding process is emerging in the European continent and it is leading to re-conceive the meta-national legislative interventions by challenging the limits of Hobbes’s Leviathan. As asserted, we ought to not take this process for granted because although there are many forms of social organization, contract is the most pervasive and the law of contract still is the most important vehicle to support and supplement private arrangements. However, the point of departure for theorizing about private law is based on experience. Consequently, despite the growing emphasis on the convergence of national legal systems in Europe, conducting research on private law theory and practice requires that imagination and creativity be matched with prudence. Proficiency has to be aligned with what we have learned from history.

Algumas generalizações para o último teorema de Fermat

Neste trabalho estudamos três generalizações para o último Teorema de Fermat. A primeira generalização trata de expoentes negativos e de expoentes racionais. Além de mostrar em que casos estas equações possuem soluções, damos uma caracterização completa para todas as soluções inteiras não-nulas existentes. A segunda generalização também trata de expoentes racionais, porém num contexto mais amplo. Aqui permitimos que as raízes n-ésimas sejam complexas, não necessariamente reais. Na terceira generalização vemos que o último Teorema de Fermat também vale para expoentes inteiros gaussianos.

Informatização da operação e da gestão de uma unidade de saúde de alta complexidade do sistema único de saúde (SUS): estudo de caso do instituto de medicina integral Prof. Fernando Figueira (Imip) sob o enfoque do isomorfismo institucional

O trabalho buscou identificar e avaliar a escolha do Imip à luz da teoria neoinstitucional, mediante os mecanismos isomórficos que caracterizam o campo das organizações de saúde. Trata-se de um estudo de caso, tendo o Imip como objeto de análise, voltado especificamente para dois modelos de informatização da operação e da gestão, a fim de verificar qual o mais adequado para as especificidades da instituição, incluindo o aspecto financeiro, custo/benefício. O primeiro modelo se refere a um sistema próprio de informatização; o segundo a um modelo de sistema de gestão já existente, comercializado por empresa especializada nesta tecnologia. A metodologia abrangeu pesquisas bibliográficas, documentais e de campo. O referencial teórico foi a teoria neoinstitucional e o trabalho de campo constou de uma pesquisa incluindo observação simples, visando compor variáveis dos dois modelos avaliados, e coleta de dados realizada por meio da aplicação de dois questionários: um questionário aberto, com os dirigentes do Imip, e um questionário misto, com cem colaboradores, utilizadores do sistema, escolhidos aleatoriamente, por sorteio. Entre os achados se identificou claras referências ao isomorfismo, principalmente o mimético, nas percepções dos indivíduos respondentes. Ao final da pesquisa, foi possível concluir que a contratação de um sistema de gestão hospitalar, já existente no mercado, concebido e comercializado por empresa de tecnologia especializada no segmento da saúde, justificou-se como a melhor escolha para a organização, pois, as semelhanças existentes entre os processos do Instituto e aqueles contidos no sistema eram muito mais relevantes que suas particularidades. Outro fator relevante levou em consideração os elevados custos para uma única instituição desenvolver e manter sozinha um sistema atualizado segundo as exigências normativas e técnicas necessárias às organizações de saúde e os padrões de qualidade da informação estabelecidos pelo SUS.

Double sampling (x)over-bar control chart for a first-order autoregressive moving average process model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cauchy-Stieltjes Integral on Time Scales in Banach Spaces and Hysteresis Operators

The play operator has a fundamental importance in the theory of hysteresis. It was studied in various settings as shown by P. Krejci and Ph. Laurencot in 2002. In that work it was considered the Young integral in the frame of Hilbert spaces. Here we study the play in the frame of the regulated functions (that is: the ones having only discontinuities of the first kind) on a general time scale T (that is: with T being a nonempty closed set of real numbers) with values in a Banach space. We will be showing that the dual space in this case will be defined as the space of operators of bounded semivariation if we consider as the bilinearity pairing the Cauchy-Stieltjes integral on time scales.

Asymptotics of zeros of polynomials arising from rational integrals

We prove that the zeros of the polynomials P.. (a) of degree m, defined by Boros and Moll via[GRAPHICS]approach the lemmiscate {zeta epsilon C: \zeta(2) - 1\ = Hzeta < 0}, as m --> infinity. (C) 2004 Elsevier B.V. All rights reserved.

Path integral quantization of generalized quantum electrodynamics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)