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Nelder-Mead optimization under linear constraints
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Analysis of Linear Systems Assisted with Scilab: An Approach from Electrical Engineering (2015 Review)
No full textThe analysis of the linear systems as well as of the signals that interact with the different elements of the system and the environment that surrounds it, requires a clear knowledge of the mathematical analysis and especially of what is known as operational calculation, as of the operational calculation it is possible, in some cases, to facilitate the search for the solutions of the problems of analysis that are raised in the investigation of the systems represented by mathematical models. Both the mathematical models that represent the systems and the signals can be defined in terms of continuous or discrete variables, for which each of these points of view requires its corresponding model, and the determination of its solution to the problem will be based on the domain over which the model is represented, whether continuous or discrete, as well as the concepts used in the spectral domain. The author assumes that the reader has a clear knowledge of Laplace, Fourier and Z transform, which are used as alternative tools for the analysis of problems in the domain where the mathematical models are described. On the other hand, brief explanations of some differential equation solving methods are presented in this book, which represent the relationships among the variables of the dynamic system defined in the continuous domain that is being studied. The purpose of introducing differential equations is to induce the method of solving difference equations, which are used as mathematical models of dynamic systems seen from a discrete domain perspective. It is important to note that the scope of this work does not include the analysis of linear systems from the stochastic perspective, because this approach requires clear knowledge of the probabilities and stochastic processes, and that this material It should form the textbook of the undergraduate course of Analysis of Linear Systems of the School of Electrical Engineering of the Central University of Venezuela, and this course studies the systems from the deterministic point of view. It should be noted that the author has used, in a very careful way, a notation that allows to discriminate clearly when the mathematical models are referred to the continuous or discrete domain. Moreover, the author makes a clear difference, in the case of the signals defined in the discrete domain, between what a function in the discrete domain means and its corresponding sequence of samples, both of which are used for the representation of the signals in the domain of discrete domain. In addition, the author has tried as far as possible to refer to the domain, without this being limited to the domain in continuous or discrete time, because in the opinion of the author, the concepts, methods and theoretical bases should not refer exclusively to the domain of time, but to any domain, thus leaving the possibility of generalizing the application of what is presented in the work, although in the area of Electrical Engineering it is very common to see the models and signals defined in the domain of time and frequency. It is appropriate to establish that throughout the work, the signals studied and their use in the analysis of the various systems, both in the continuous and discrete domain, are considered real. That is, they are signals that represent measures in the set of real numbers, or in mathematical terms are signals represented by functions whose ranges correspond to the set of real numbers. In addition, it must be taken into account that the signals are modeled by functions defined in the domain of real or integer numbers, depending on whether the signals represent measurements in the continuous or discrete domain, respectively
Una extensión del método de Nelder Mead a problemas de optimización no lineales enteros mixtos
Get PDFAbstractThis article presents a new algorithm based on the Nelder-Mead simplex algorithmic method for identifying a local optimum, at least on unconstrained nonlinear mixed-integer problems. The algorithmic method, Integer Mixed Simplex Algorithm (IMSA), so called by the author, is based on a double simplex structure, which is composed of a real n-dimensional simplex structure (real simplex) and an integer n-dimensional simplex structure (integer simplex). The original Nelder-Mead operations are applied on the real simplex. Meanwhile, a novel group of operations are applied on the integer simplex. This new set of operations, together with the original Nelder-Mead operations, guarantee a new trail point at each IMSA iteration in the search of the local optimum in the integer real mixed 2n-dimensional numerical field ℝn×ℤn without the need of integer to real conversions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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