514 research outputs found
Modelling and controlling traffic behaviour with continuous Petri nets
Traffic systems are discrete systems that can be heavily populated. One way of overcoming the state explosion problem inherent to heavily populated discrete systems is to relax the discrete model. Continuous Petri nets (PN) represent a relaxation of the original discrete Petri nets that leads to a compositional formalism to model traffic behaviour. This paper introduces some new features of continuous Petri nets that are useful to obtain realistic but compact models for traffic systems. Combining these continuous PN models with discrete PN models of traffic lights leads to a hybrid Petri net model that is appropriate for predicting traffic behaviour, and for designing trac light controllers that minimize the total delay of the vehicles in the system
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Genetic susceptibility to methylmercury developmental neurotoxicity matters
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Steady State Analysis of Flexible Nets
The modeling and analysis of complex dynamic
systems, such as those in manufacturing, logistics and biology,
require powerful analysis methods for their study and optimization.
A significant modeling and analysis challenge posed by
both, artificial and natural systems, is the existence of uncertain
parameters. Flexible Nets is a novel modeling formalism, inspired
by Petri nets, that can handle different types of uncertain
parameters in a natural way. This paper develops an efficient
method to analyse the evolution of a system modeled by a Flexible
Net in the long run. More precisely, the method focuses on the
computation of steady state bounds for an objective function of
interest. The method makes use of a set of constraints, expressed
as linear inequalities, that the state variables must satisfy in
the steady state. In order to account for systems that do not
reach a constant steady state, the developed constraints allow
the system state to switch among different values, i.e. the steady
state variables are not forced to be constant.European Commission: FormalBio Contract No: 623995,
Call reference: FP7-PEOPLE-2013-IE
On the performance evaluation of multi-guarded marked graphs with single-server semantics
In discrete event systems, a given task can start executing when all the required input data are available. The required input data for a given task may change along the evolution of the system. A way of modeling this changing requirement is through multi-guarded tasks. This paper studies the performance evaluation of the class of marked graphs extended with multi-guarded transitions (or tasks). Although the throughput of such systems can be computed through Markov chain analysis, two alternative methods are proposed to avoid the state explosion problem. The first one obtains throughput bounds in polynomial time through linear programming. The second one yields a small subsystem that estimates the throughput of the whole system.Peer ReviewedPostprint (author's final draft
Performance optimization of elastic systems using buffer resizing and buffer insertion
Buffer resizing and buffer insertion are two transformation techniques for the performance optimization of elastic systems. Different approaches for each technique have already been proposed in the literature. Both techniques increase the storage capacity and can potentially contribute to improve the throughput of the system. Each technique offers a different trade-off between area cost and latency. This paper presents a method that combines both techniques to achieve the maximum possible throughput while minimizing the cost of the implementation. The provided method is based on mixed integer linear programming. A set of experiments is designed to show the feasibility of the approach.Peer ReviewedPostprint (published version
Eureka
Comunicación presentada en el XV Workshop de Rebiun "Datos y Bibliotecas", celebrado en Castellón los días 29 y 30 de septiembre de 201
Explainable artificial intelligence toward usable and trustworthy computer-aided early diagnosis of multiple sclerosis from Optical Coherence Tomography
Background: Several studies indicate that the anterior visual pathway
provides information about the dynamics of axonal degeneration in Multiple
Sclerosis (MS). Current research in the field is focused on the quest for the
most discriminative features among patients and controls and the development of
machine learning models that yield computer-aided solutions widely usable in
clinical practice. However, most studies are conducted with small samples and
the models are used as black boxes. Clinicians should not trust machine
learning decisions unless they come with comprehensive and easily
understandable explanations. Materials and methods: A total of 216 eyes from
111 healthy controls and 100 eyes from 59 patients with relapsing-remitting MS
were enrolled. The feature set was obtained from the thickness of the ganglion
cell layer (GCL) and the retinal nerve fiber layer (RNFL). Measurements were
acquired by the novel Posterior Pole protocol from Spectralis Optical Coherence
Tomography (OCT) device. We compared two black-box methods (gradient boosting
and random forests) with a glass-box method (explainable boosting machine).
Explainability was studied using SHAP for the black-box methods and the scores
of the glass-box method. Results: The best-performing models were obtained for
the GCL layer. Explainability pointed out to the temporal location of the GCL
layer that is usually broken or thinning in MS and the relationship between low
thickness values and high probability of MS, which is coherent with clinical
knowledge. Conclusions: The insights on how to use explainability shown in this
work represent a first important step toward a trustworthy computer-aided
solution for the diagnosis of MS with OCT
Cine y enfermedades mentales
El presente trabajo nace con el objetivo de analizar la representación de las enfermedades mentales en la gran pantalla para comprobar si muestran una visión fidedigna a la realidad o una versión estereotipada de quienes padecen este tipo de enfermedades El procedimiento a seguir consistirá en la observación de varias películas en las que se reflejen distintas enfermedades mentales, analizando así el modo en el que se representa el comportamiento de las personas afectadas, a partir de manuales profesionales de psicología. De este modo comprobaremos si se reflejan de manera fidedigna estos comportamientos o si atienden a realidades estereotipadas. Posteriormente se realizará un cuestionario, combinando la metodología cualitativa y cuantitativa, para comprobar el impacto que pueden tener dichas películas a la hora de influir en la percepción de la población a cerca de las enfermedades mentales. Todo ello con el fin de comprobar si estas películas pueden servir a la comunidad educativa como recurso para visibilizar y concienciar a la población sobre la realidad de las personas que padecen enfermedades mentales y desmontar así los estereotipos que la gran pantalla ha podido implantar en el subconsciente colectivo.Palabras clave: enfermedad mental, cine, estereotipo, perjuicio, recurso educativo <br /
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