Person:
Gómez González, Daniel

First Name

Daniel

Last Name

Gómez González

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Estudios estadísticos

Department

Estadística y Ciencia de los Datos

Area

Estadística e Investigación Operativa

Identifiers

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Now showing 1 - 10 of 11

New Aggregation Approaches with HSV to Color Edge Detection
(Atlantis Press, 2022-09-16) Flores Vidal, Pablo Arcadio; Gómez González, Daniel; Castro Cantalejo, Javier; Montero, Javier
The majority of edge detection algorithms only deal with grayscale images, while their use with color images remains an open problem. This paper explores different approaches to aggregate color information of RGB and HSV images for edge extraction purposes through the usage of the Sobel operator and Canny algorithm. This paper makes use of Berkeley’s image data set, and to evaluate the performance of the different aggregations, the F-measure is computed. Higher potential of aggregations with HSV channels than with RGB channels is found. This article also shows that depending on the type of image used, RGB or HSV, some methods are more appropriate than others.
Allocating slacks in stochastic PERT network
(Springer, 2014-03) Castro Cantalejo, Javier; Gómez González, Daniel; Tejada Cazorla, Juan Antonio
The SPERT problem was defined, in a game theory framework, as the fair allocation of the slack or float among the activities in a PERT network previous to the execution of the project. Previous approaches tackle with this problem imposing that the durations of the activities are deterministic. In this paper, we extend the SPERT problem into a stochastic framework defining a new solution that tries also to maintain the good performance of some other approaches that have been defined for the deterministic case. Afterward, we present a polynomial algorithm for this new solution that also could be used for the calculation of other approaches founded in the deterministic SPERT literature.
A polynomial rule for the problem of sharing delay costs in PERT networks
(Pergamon-Elsevier Science Ltd, 2008) Castro Cantalejo, Javier; Gómez González, Daniel; Tejada Cazorla, Juan Antonio
In this paper we define the weighted serial cost sharing rule for the cost allocation problem.We apply this new rule to the problem of sharing delay costs in a PERT network. This rule belongs to the Core and is the Weighted Shapley Value for a particular game. Furthermore, we present a characterization of this rule and a polynomial algorithm for its calculation.
A rule for slack allocation proportional to the duration in a PERT network
(Elsevier Science, 2008) Castro Cantalejo, Javier; Gómez González, Daniel; Tejada Cazorla, Juan Antonio
In this paper, we define a new rule for the resolution of the slack allocation problem in a PERT network. This problem exists of allocating existing extra time in some paths among the activities belonging to those paths. The allocation rule that we propose assigns extra time to the activities proportionally to their durations in such a way that no path duration exceeds the completion time of the whole project. This time allocation enables us to make a schedule for the PERT project under study. We give two characterizations of the rule and we compare it with others that have been previously defined in the literature.
Utilización de metodologías activas de enseñanza para el aprendizaje de las matemáticas, centradas en el estudiante y desarrolladas en el espacio innovador de una hiperaula
(2021-01-14) Fernández-Salinero Miguel, Carolina; Riva Picatoste, Beatriz De la; Roanes Lozano, Eugenio; Roanes Macías, Eugenio; Gómez González, Daniel; Muñoz Fernández, Gustavo Adolfo; Lucas Burgos, Daniel; Flores Vidal, Pablo Arcadio; Giorgis, Valentina; Sáez Maestro, Eva
La inauguración de la hiperaula de la Facultad de Educación-CFP (UCM) en abril de 2019 y su prioridad de uso para el Máster en Formación del Profesorado de Educación Secundaria, Bachillerato, Formación Profesional y Enseñanza de Idiomas durante el curso académico 2019-2020, supone un marco experimental absolutamente novedoso. Estas circunstancias permiten a la responsable del proyecto y a varios profesores participantes en el mismo, algunos de ellos docentes en el mencionado Máster y pertenecientes a diferentes Departamentos y Facultades de la UCM, así como a varios alumni y personal de administración y servicios implicados en el proyecto, utilizar este innovador espacio para la enseñanza de la asignatura de "Innovación docente e iniciación a la investigación educativa" (especialidad de matemáticas del Máster en Formación del Profesorado), empleando para ello metodologías activas de enseñanza centradas en el estudiante.
Auctions: A New Method for Selling Objects with Bimodal Density Functions
(Springer Nature, 2022-04-03) Castro Cantalejo, Javier; Espínola Vílchez, Rosario; Gutiérrez García-Pardo, Inmaculada; Gómez González, Daniel
In this paper we define a new auction, called the Draw auction. It is based on the implementation of a draw when a minimum price of sale is not reached. We find that a Bayesian Nash equilibrium is reached in the Draw auction when each player bids his true personal valuation of the object. Furthermore, we show that the expected profit for the seller in the Draw auction is greater than in second-price auctions, with or without minimum price of sale. We make this affirmation for objects whose valuation can be modeled as a bimodal density function in which the first mode is much greater than the second one. Regarding the Myerson auction, we show that the expected profit for the seller in the Draw auction is nearly as good as the expected profit in the optimal auction, with the difference that our method is much more simple to implement than Myerson’s one. All these results are shown by computational tests, for whose development we have defined an algorithm to calculate Myerson auction.
A new approach to Color Edge Detection
(2019-08) Flores Vidal, Pablo Arcadio; Gómez González, Daniel; Castro Cantalejo, Javier; Villarino, Guillermo; Montero, Javier
Most edge detection algorithms deal only with grayscale images, and the way of adapting them to use with RGB images is an open problem. In this work, we explore different ways of aggregating the color information of a RGB image for edges extraction, and this is made by means of well-known edge detection algorithms. In this research, it is been used the set of images from Berkeley. In order to evaluate the algorithm’s performance, F measure is computed. The way that color information -the different channels- is aggregated is proved to be relevant for the edge detection task. Moreover, post-aggregation of channels performed significatively better than the classic approach (pre-aggregation of channels).
Algunas aportaciones sobre representación de preferencias
(Universidad Complutense de Madrid, Servicio de Publicaciones, 2004) Gómez González, Daniel; Montero de Juan, Francisco Javier; Yáñez Gestoso, Francisco Javier
En la mayoría de los problemas de decisión multicriterio se supone un conocimiento a priori de los criterios. Sin embargo, esta hipótesis no parece ser la más adecuada en diversas situaciones. En esta línea de búsqueda de los criterios subyacentes del decisor, surge el concepto de dimensión inicialmente propuesto por Dushnik y Miller. Sin embargo, este concepto solamente es aplicado a órdenes parciales. En esta memoria se define un nuevo concepto de dimensión que permitirá la representación de cualquier relación de preferencia no reflexiva, se analizaran propiedades asociadas a este concepto así como algoritmos para su cálculo. Este nuevo concepto de dimensión permite su extensión al contexto difuso permitiendo una representación de cualquier relación de preferencia difusa, sin más que analizar la secuencia de alfa-cortes de dicha relación. El análisis de las relaciones de preferencia permitirá el desarrollo de diversos algoritmos interactivos de clasificación difusa de imágenes digitales obtenidas vía satélite. Se desarrollan algoritmos no supervisados de clasificación desde dos perspectivas diferentes, el conceptó de variacional de un píxel y la coloración de grafos difusos que modelizan la imagen digital.
Polynomial calculation of the Shapley value based on sampling
(Pergamon-Elsevier Science Ltd, 2009-05) Castro Cantalejo, Javier; Gómez González, Daniel; Tejada Cazorla, Juan Antonio
In this paper we develop a polynomial method based on sampling theory that can be used to estimate the Shapley value (or any semivalue) for cooperative games. Besides analyzing the complexity problem, we examine some desirable statistical properties of the proposed approach and provide some computational results.
Improving polynomial estimation of the Shapley value by stratified random sampling with optimum allocation
(Pergamon-Elsevier, 2017) Castro Cantalejo, Javier; Gómez González, Daniel; Molina, Elienda; Tejada Cazorla, Juan Antonio
In this paper, we propose a refinement of the polynomial method based on sampling theory proposed by Castro et al. (2009) to estimate the Shapley value for cooperative games. In addition to analyzing the variance of the previously proposed estimation method, we employ stratified random sampling with optimum allocation in order to reduce the variance. We examine some desirable statistical features of the stratified approach and provide some computational results by analyzing the gains due to stratification, which are around 30% on average and more than 80% in the best case.