185 research outputs found
Imaginary-axis crossing points in root loci that depend polynomially on the gain
This technical note discusses the crossing with the stability boundary for the root loci that polynomially depend on the gain. A simple calculation method based on reflected polynomials is provided. The trend of the roots is also determined, which allows studying the gain margin as well as the minimum gain so that all the roots are within the stable region. Finally, these concepts are illustrated with two case studies
A polynomial-time algorithm for optimization of quadratic pseudo-boolean functions
We develop a polynomial-time algorithm to minimize pseudo-Boolean functions. The computational complexity is O(n â–¡(15/2)), although very conservative, it is su_cient to prove that this minimization problem is in the class P. A direct application of the algorithm is the 3-SAT problem, which is also guaranteed to be in the class P with a computational complexity of order O(n â–¡(45/2)). The algorithm was implemented in MATLAB and checked by generating one million matrices of arbitrary dimension up to 24 with random entries in the range [-50; 50]. All the experiments were successful
Actividades divulgativas de matemáticas
Las Matemáticas se presentan a menudo como una ciencia abstracta alejada de la vida cotidiana. Sin embargo, esta disciplina está presente en nuestro alrededor de manera palpable. La matemática presenta un mayor interés entre los ciudadanos a partir del contacto y la experimentación con la realidad que nos rodea. Es en ella donde es posible plantear actividades de Ãndole matemático que permitan una comprensión más profunda del medio en el que vivimos y, al mismo tiempo, transmitan de forma más directa que las matemáticas son una herramienta imprescindible en nuestra vida diaria. La red "Actividades divulgativas de matemáticas" tiene como objetivo desarrollar actividades a través de las cuales podamos mostrar las matemáticas como una potente herramienta para conocer las caracterÃsticas de nuestro ambiente vital. En esta memoria, describiremos las actividades más importantes tales como conferencias, el diseño de una ruta matemática por el campus de la Universidad de Alicante y la publicación de un libro de divulgación
Algunas estructuras matemáticas del campus de la Universidad de Alicante
Las Matemáticas alcanzan mayor interés entre los ciudadanos a partir del contacto y la experimentación con la realidad cotidiana que nos rodea. Es justamente en ella donde es posible plantear actividades de Ãndole matemático que permitan una comprensión más profunda del medio en el que vivimos y, al mismo tiempo, transmitir de forma más directa que las matemáticas son una herramienta imprescindible en nuestra vida diaria. El Campus de la Universidad de Alicante ha sido desde su creación un espacio relevante considerado en algunas ocasiones como uno de los mejores campus universitarios, no sólo de España sino también de Europa. A lo largo de una extensión de alrededor de un millón de metros cuadrados, encontramos motivos suficientes para tratas varios aspectos matemáticos que aparecen en muchos de sus edificios y recintos. En este trabajo mostraremos algunos elementos matemáticos que descubrimos a lo largo de un pequeño itinerario que hemos realizado dentro del campus. AsÃ, el principal objetivo es el de ilustrar muchos conocimientos matemáticos de una forma amena y divertida. De esta manera, el contacto con la realidad llegará entonces a lÃmites insospechados y nos hará, en definitiva, participar de ella e idear otra realidad matemática paralela
Sacralidad y singularidad de los espacios de enterramiento en Totana (Murcia) a partir del siglo XVI: El cementerio municipal de Nuestra Señora del Carmen
In this work we study the change of location of the different cemeteries of Totana in the 19th century. Until 1811 these spaces were located in temples and hermitages. The epidemics of the early nineteenth century forced to carry out the provisions that Carlos III had published in the eighteenth century which decreed the removal of burials from urban centres. This is how local authorities began the construction of a first cemetery in the population in 1813. This place was in use until 1885 when the current cemetery of «Nuestra Señora del Carmen» was built. This cemetery is further away from the population and follows an aesthetic and hygienist model established by the diocesan architect Justo Millán Espinosa.En este trabajo estudiamos el cambio de ubicación de los distintos cementerios de Totana en el siglo XIX. Hasta 1811 estos espacios se situaron en templos y ermitas. Las epidemias de principios del siglo XIX obligaron a materializar las disposiciones que Carlos III habÃa publicado en el siglo XVIII y que decretaban alejar los enterramientos de los núcleos urbanos. Fue asà como las autoridades locales iniciaron la construcción de un primer cementerio en la población en 1813. Este ámbito estuvo en uso hasta que en 1885 se edificó el cementerio actual, el de Nuestra Señora del Carmen, más alejado de la población y siguiendo un modelo estético e higienista establecido por el arquitecto diocesano Justo Millán Espinosa
Regional labour markets and interregional migration: Spain, 1963-1990.
The Ph.D. thesis submitted under this title consists of three main parts. I start with a description of the regional labour markets in Spain in the last few years. It is followed by a theoretical model of interregional migration, to finish with an empirical exercise on the economic determinants of migration within Spain in recent years. The first two chapters are dedicated to analyze the composition of the two sides of the labour market, employment and unemployment, respectively, according to various dimensions, such as sectoral employment, sex, age, time unemployed. This study includes not only a description of the evolution along time for each region in Spain, but also a comparison of the relevant structures of the labour market across regions, paying particular attention to the degree of geographical homogeneity of both employment and unemployment. The theoretical part of the thesis consists of a model of interregional migration. Using recent developments in search theory, the idea consists of being able to specify a migration function from a micro-economic model of utility-maximizing individuals. Each individual will decide the proportion of the searching time he dedicates to search for a job in each region, as a function of, amongst other things, the probability of getting a job in each one of them. However, at the aggregate level we have to take into account the existence of an externality present in the model, as these probabilities depend on the allocation of searching time decided by the individuals. Once this system is solved, interregional migration appears, under certain assumptions, as the product of the number of effective job-seekers at any time from one region into another times the probability of getting a job in this other region. This model concludes with an study of the comparative statics of the migration function with respect to certain exogenous variables. Finally, the last part is dedicated to an estimation of the reduced form derived from the same principles as the theoretical model. It is done for the case of the migration flows that took place amongst the Spanish regions from 1963 till 1986, and it examines the economic determinants of interregional migration, addressing the issue of why these movements came down when they were more needed to reduce unemployment differentials
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