1,315 research outputs found
CEST and MEST: Tools for the simulation of radio frequency electric discharges in waveguides
This is the author’s version of a work that was accepted for publication in Simulation Modelling Practice and Theory. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Simulation Modelling Practice and Theory, 16, 9, (2008) http://dx.doi.org/10.1016/j.simpat.2008.08.002In this paper we present two software tools for the simulation of electron multiplication processes in radio frequency (RF) waveguides. The electric discharges are caused by the multiplication of a small initial number of electrons. These are accelerated by the RF field and produce new electrons either by collisions with the walls of the waveguide (ripping new electrons from them), or by ionization of the neutral atoms of a gas inside the device.
MEST allows simulating the Multipactor effect, a discharge produced in vacuum and generated by the collision of the electrons with the walls. CEST simulates the discharge when in addition a neutral gas is present in the waveguide, at pressures lower than ground levels (often denominated Corona discharge). The main characteristic of both tools is that they implement individual-based, microscopic models, where every electron is individually represented and tracked. In the case of MEST, the simulation is discrete-event, as the trajectory of each electron can be computed analytically. In CEST we use a hybrid simulation approach. The trajectory of each electron is governed by the Langevin stochastic differential equations that take into account a deterministic RF electric force and the random interaction with the neutral atom background. In addition, wall and ionizing collisions are modelled as discrete events.
The tools allow performing batches of simulations with different wall coating materials and gases, and have produced results in good agreement with experimental and theoretical data. The different output forms generated at run-time have proven to be very useful in order to analyze the different discharge processes. The tools are valuable for the selection of the most promising coating materials for the construction of the waveguide, as well as for the identification of safe operating parameters.Work sponsored by the ESA, TRP activity program 17025/03/NL/EC: Surface Treatment and Coating
A VLSI-oriented and power-efficient approach for dynamic texture recognition applied to smoke detection
The recognition of dynamic textures is fundamental in processing image sequences as they are very common
in natural scenes. The computation of the optic flow is the most popular method to detect, segment and analyse
dynamic textures. For weak dynamic textures, this method is specially adequate. However, for strong dynamic
textures, it implies heavy computational load and therefore an important energy consumption. In this paper,
we propose a novel approach intented to be implemented by very low-power integrated vision devices. It
is based on a simple and flexible computation at the focal plane implemented by power-efficient hardware.
The first stages of the processing are dedicated to remove redundant spatial information in order to obtain
a simplified representation of the original scene. This simplified representation can be used by subsequent
digital processing stages to finally decide about the presence and evolution of a certain dynamic texture in the
scene. As an application of the proposed approach, we present the preliminary results of smoke detection for
the development of a forest fire detection system based on a wireless vision sensor network.Junta de Andalucía (CICE) 2006-TIC-235
Introducing probabilistic celular automata. A versatile extension of Game of Live
The "Game of life" model was created in 1970 by the mathematician Jonh Horton Conway
using cellular automata. Since then, di erent extensions of these cellular automata have been
used in many applications, such as car traffic control or baggage traffic in an airport.
These extensions introduce ideas not only from cellular automata models but also from neural
networks theory.
In this work, we introduce probabilistic cellular automata which include non-deterministic
rules for transitions between successive generations of the automaton together with probabilistic
decisions about life and death of the cells in next generation of the automaton. This way,
more realistic situations can be modeled and the obtained results are also non-deterministic.
As an example of use, an implementation of this probabilistic cellular automaton has been
developed using it for simulating tissues evolution. The authors are specially interested in
simulations of cancerous tissues.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
New rules for improving CAS capabilities when computing improper integrals. Applications in Math Education
In many Engineering applications the computation of improper integrals is a need. In
[1] we pointed out the lack of some CAS when computing some types of improper integrals.
Even more, the work developed showed that some improper integrals can not be computed
with CAS using their build-in procedures.
In this talk we will develop new rules to improve CAS capabilities in order to compute
new improper integrals
We will show some examples of improper integrals that CAS asMATHEMATICA, MAPLE,
DERIVE or MAXIMA can not compute. Using advance techniques as Laplace and Fourier
transforms or Residue Theorem in Complex Analysis, we will be able to develop new rules
schemes for these improper integrals.
We will also describe the conclusions obtained after using these new rules with our Engineering
students when teaching Advanced Calculus.
[1] José L.Galán-García, Gabriel Aguilera-Venegas, María Á. Galán-García, Pedro
Rodríguez-Cielos, Iván Atencia-Mc.Killop. Improving CAS capabilities: New rules for
computing improper integrals. Applied Mathematics and Computation. Volume 316, 1
January 2018, Pages 525-540.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
A RBES for Generating Automatically Personalized Menus
Food bought at supermarkets in, for instance, North America or the European Union, give comprehensive information about ingredients and allergens. Meanwhile, the menus of restaurants are usually incomplete and cannot be normally completed by the waiter. This is specially important when traveling to countries with a di erent culture. A curious example is "calamares en su tinta" (squid in its own ink), a common dish in Spain. Its brief description would
be "squid with boiled rice in its own (black) ink", but an ingredient of its sauce is flour, a fact very important for celiacs. There are constraints based on religious believes, due to food allergies or to illnesses, while others just derive from personal preferences. Another complicated situation arise in hospitals, where the doctors' nutritional recommendations have to be added to the patient's usual constraints. We have therefore designed and developed a Rule Based Expert System (RBES) that can address these problems. The rules derive directly from the recipes of the di fferent dishes and contain the information about the required ingredients and ways of cooking. In fact, we distinguish: ingredients and ways of cooking, intermediate
products (like sauces, that aren't always made explicit) and final products (the dishes listed in the menu of the restaurant). For a certain restaurant, customer and instant, the input to the RBES are: actualized stock of ingredients and personal characteristics of that customer.
The RBES then prepares a "personalized menu" using set operations and knowledge extraction (thanks to an algebraic inference engine [1]). The RBES has been implemented in the computer algebra system MapleTM2015. A rst version of this work was presented at "Applications of Computer Algebra 2015" (ACA'2015) conference. The corresponding abstract is available at [2].Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Gestión del conocimiento, innovación y tecnología desde las capacidades dinámicas
El enfoque de capacidades dinámicas está experimentando una aplicación generalizada en las áreas de estudio relacionadas con la gestión del conocimiento, la innovación y la tecnología, con aplicación a tipos específicos de empresa, como la familiar y las de carácter emprendedor. En esta conferencia revisamos líneas emergentes de investigación en las áreas mencionadas.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
A fast functional approach to personalized menus generation using set operations
The authors developed some time ago a RBES devoted to preparing personalized menus at
restaurants according to the allergies, religious constraints, likes and other diet requirements
as well as products availability. A first version was presented at the "Applications of Computer
Algebra 2015" (ACA'2015) conference and an improved version to the "5th European
Seminar on Computing" (ESCO2016). Preparing personalized menus can be specially
important when traveling abroad and facing unknown dishes in a menu. Some restaurants
include icons in their menu regarding their adequateness for celiacs or vegetarians and vegans,
but this is not always a complete information, as it doesn't consider, for instance, personal
dislikes or uncommon allergies. The tool previously developed can obtain, using logic deduction,
a personalized menu for each customer, according to the precise recipes of the restaurant
and taking into account the data given by the customer and the ingredients out of stock (if
any). Now a new approach has been followed, using functions and set operations and the
speed has been increased by three orders of magnitude, allowing to deal with huge menus
instantly. Both approaches have been implemented on the computer algebra system Maple
and are exemplified using the same recipes in order to compare their performances.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Computer Algebra-based RBES personalized menu generator
People have many constraints concerning the food they eat. These constraints
can be based on religious believes, be due to food allergies or to illnesses, or can
be derived just from personal preferences. Therefore, preparing menus at hospitals
and restaurants can be really complex. Another special situation arise when travel-
ing abroad. It is not always enough to know the brief description in the restaurant
menu or the explanation of the waiter. For example, “calamares en su tinta” (squid
in its own ink) is a delicious typical Spanish dish, not well-known abroad. Its brief
description would be “squid with boiled rice in its own (black) ink”. But an in-
gredient (included in a small amount, in order to thicken the sauce) is flour, a fact
very important for someone suffering from celiac disease. Therefore, we have con-
sidered that it would be very interesting to develop a Rule Based Expert System
(RBES) to address these problems. The rules derive directly from the recipes and
contain the information about required ingredients and names of the dishes. We
distinguish: ingredients and ways of cooking, intermediate products (like “mayon-
naise”, that doesn’t always appear explicitly in the restaurants’ menus) and final
products (like “seafood cocktail”, that are the dishes listed in the restaurant menu).
For each customer at a certain moment, the input to the system are: on one hand,
the stock of ingredients at that moment, and on the other, the religion, allergies and
restrictions due to illnesses or personal preferences of the customer. The RBES
then constructs a “personalized restaurant menu” using set operations and knowl-
edge extraction (thanks to an algebraic Groebner bases-based inference engine[1]).
The RBES has been implemented in the computer algebra system
Maple TM 18(us-ing its convenient Embedded Components) and can be run from computers and tablets using Maple TM or the Maple TM PlayerUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Desarrollo de métodos rápidos para verificar la eficacia fungicida de sustancias desinfectantes /
INTRODUCCIÓN: Los datos epidemiológicos que poseemos en nuestro país señalan que la mayor parte de los brotes de toxiinfecciones alimentaria se desencadenan en el ámbito doméstico. Debido a ello, cada vez más se están desarrollando formulaciones químicas con actividad desinfectante para ser utilizadas en el hogar. La mayoría de los productos desarrollados tienen como objetivo el actuar como bactericidas. Sin embargo, poco se estudia respecto a su posible actividad fungicida. Encontrado microorganismos patógenos, como Candida albicans y otros alterantes. Por este motivo, nuestro trabajo pretende comparar la actividad fungicida de los desinfectantes utilizados en el ámbito doméstico, para conocer su eficacia real y su aplicabilidad. Pretendemos evaluar el empleo de las técnicas impedanciométricas, ya que se trata de una metodología particularmente adecuada a pruebas de desinfectantes en superficies. El protocolo deja la adherencia en el mismo estado morfológico y no los enfrenta a un estrés por remoción y por lo tanto no influye en la eficacia del desinfectante(Gibson y col., 1995). OBJETIVOS: Evaluar la eficacia funguicida de los productos comerciales de uso domestico, aplicando las normas internacionales de evaluación UNE EN-1275 y 1650. Desarrollar una técnica rápida de evaluación de estos mismos productos comerciales. Desarrollar sistemas que simulen situaciones reales de uso. Verificar su eficacia, una vez adaptada la metodología, ensayar y comparar la eficacia de los diferentes desinfectantes en condiciones reales de uso. MATERIAL Y MÉTODO: La fase experimental del proyecto se realizó en 5 etapas: Aplicación de las normas Españolas UNE-EN 1275 y 1650 para la evaluación de la actividad fungicida en 20 productos comerciales. Diseñar un método rápido de screening a dos concentraciones y dos tiempos de contacto, para ayudar a discriminar los compuestos y poder encontrar su rango de acción. Adaptar las normas a una técnica impedanciométrica, para automatizarla y permitir una detección de la actividad desinfectante en un menor tiempo. Analizar los efectos de las condiciones ambientales en la viabilidad de las cepas fúngicas en varias superficies. Emplear la técnica de epifluorescencia directa, con tinción vital de fluorescencia y captura de imagen. Se evaluó la actividad fungicida en tela de algodón RESULTADOS: Nuestros resultados señalan que el producto con hipoclorito sódico presenta mayor actividad fungicida, tanto para las levaduras como para esporas de mohos, así como el glutaraldehído, que también supero las 2 normas UNE EN-1275 y 1650. Al mismo tiempo, hemos constatado la aplicabilidad de la impedancia como sistema para evaluar el recuento de estos microorganismos y poder evaluar la eficacia fungicida de diversas sustancias en un menor tiempo y en con una mayor eficacia. CONCLUSIONES: Es posible la adaptación de la metodología estándar a otra rápida, con una reducción en el tiempo de incubación y una simplificación de las pruebas a realizar. La adaptación del protocolo normalizado a un método de screening se realizo seleccionando dos concentraciones de los productos a emplear (80% y 20%) a dos tiempos de contacto (15 y 60 minutos). Los resultados obtenidos permiten clasificar los productos por diferentes niveles de eficacia. El producto con más amplio espectro fungicida es el hipoclorito sódico (lejía), tanto para levaduras como para esporas de mohos. Con este producto se consigue una reducción de más de 5 unidades logarítmicas de recuento con la menor concentración en menos de 5 minutos de contacto con gran diferencia respecto al resto. Los productos estudiados poseen una actividad desigual, dependiendo de las condiciones del ensayo (concentración, el tiempo de exposición y el microorganismo utilizado).INTRODUCTION The epidemiological data that we have in our country show that most food poisoning outbreaks happen in home environment. For this reason, formulations of detergents with disinfectant activity are being developed. Most of the new products act as bactericides. However, there is not much information about their possible fungicide activity except from some pathogen microoganisms like Candida. The main aim of this study was to compare fungicide activity of disinfectants most commonly used at home in order to know their real efficiency and applicability. Impedanciometric techniques were used as an appropriated methodology to test disinfectant in surfaces. The protocol left the adherence in the same morphologic state and did not confront them to stress by removal and therefore did not have influence in the disinfectant efficiency (Gibson et al., 1995). OBJECTIVES. To evaluate the fungicide efficiency of domestic-use commercial products, applying the international norm of evaluation (UNE EN-1275 and 1650). To develop a fast evaluation technique of the same commercial products. To develop systems that simulate real situations. To verify their efficiency, once the methodology is adapted, test and compare the efficiency of the different disinfectants in real use conditions. RESULTS. Our results showed that the product with sodium hypoclorite and glutaraldehide both had the higher fungicide activity for yeast and mold spores. At the same time, we constated the applicability of the impedance as a system to count these microorganisms and evaluated the fungicide efficiency of several substances in less time and with more efficiency. CONCLUSIONS. It was possible to adapt the standard methodology to a faster one, with a reduction in time of incubation and a simplification of the tests. The adaptation of the standardised protocol to a screening method was done selecting two concentrations of the products (80% and 20%) and two contact times (15 and 60 minutes). The results obtained allowed the classification of the products by efficiency levels. The product with higher fungicide activity was the sodium hypochlorite (bleach), both for yeast and mold spores. With this product was obtained a reduction of more than 5 logarithmic units with the smaller concentration in less than 5 minutes of contact and with a high difference with the others. The studied products had different activity, depending on the test conditions (concentration, exposure time and microorganisms used)
Making more flexible ATISMART+ model for traffic simulations using a CAS
Traffic simulations usually require the search of a path to join two different
points. Dijkstra’s algorithm [1] is one of the most commonly used for this task due
to its easiness and quickness. In [2, 3] we developed an accelerated time simulation
of car traffic in a smart city using Dijkstra’s algorithm to compute the paths.
Dijkstra’s algorithm provides a shortest path between two different points but
this is not a realistic situation for simulations. For example, in a car traffic situa-
tion, the driver may not know the shortest path to follow. This ignorance can be
produced, among others, because one of the following two facts: the driver may
not know the exact length of the lanes, or, even knowing the exact length, the driver
may not know how to find the shortest path. Even more, in many cases, a mixture
of both facts occurs.
A more realistic simulation should therefore consider these kind of facts. The
algorithm used to compute the path from one point to another in a traffic simulation
might consider the possibility of not using the shortest path.
In this talk, we use a new probabilistic extension of Dijkstra’s algorithm which
covers the above two situations. For this matter, two different modifications in Di-
jkstra’s algorithm have been introduced: using non-exact length in lanes, and the
choice of a non-shortest path between two different points. Both modifications are
used in a non-deterministic way by means of using probability distributions (classi-
cal distributions such as Normal or Poisson distributions or even "ad hoc" ones). A
precise, fast, natural and elegant way of working with such probability distributions
is the use of a CAS in order to deal with exact and explicit computations.
As an example of use of this extension of Dijkstra’s algorithm, we will show
the ATISMART+ model. This model provides more realistic accelerated time sim-
ulations of car traffics in a smart city and was first introduced in [4] and extended
in [5]. This model was developed combining J
AVA
for the GUI and M
AXIMA
for
the mathematical core of the algorithm.
The studies developed in the above mentioned works, dealt with Poisson, Ex-
ponential, Uniform and Normal distributions. In this talk we will introduce, as
a novelty, the possibility of using other continuous probability distributions such
as: Lognormal, Weibul, Gamma, Beta, Chi-Square, Student’s t, Z, Pareto, Lo-
gistic, Cauchy or Irwin-Hall, and other discrete distributions such as: Bernouille,
Rademacher, Binomial, Geometric, Negative Binomial or Hypergeometric. Even
1
more, this new version allows to deal with any “ad-hoc” continuous, discrete or
mixed user’s distributions. This fact improves the flexibility of ATISMART+ model.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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