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- PublicationOptimización del diseño de parámetros: Método Forest-Genetic univariante(Universidad Centroccidental Lisandro Alvarado, 2016) Villa-Murillo, Adriana; Carrión García, Andrés; Sozzi Rodríguez, Antonio José; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio[EN] In the 80¿s, Dr Genichi Taguchi developed a methodology for processes and product parameters design improvement known as the Taguchi methodology. Different proposals have emerged involving artificial intelligence techniques. Our proposal consists of a hybrid methodology that combines Random Forest (RF) and Genetic Algorithms (GA) in three phases: normalization, modeling and optimization. The first phase corresponds to the previous preparation of the data set by using normalization functions. In the modeling, the objective function is determined using strategies based on RF to predict the value of the response in a given set of parameters. Finally, in the optimization phase, the optimal combination of the parameter levels is obtained by integrating properties given by our modeling scheme into the corresponding GA. The results are compared numerically with the contributions recently found in the literature. Our methodological proposal focuses on the most important variables resulting from the RF modeling process, which allows to develop and direct more efficiently the new generations in the optimization phase, and consequently, achieve significant improvements in the quality objective considered.
- PublicationForest-Genetic method to optimize parameter design of multiresponse experiment(Sociedad Iberoamericana de Inteligencia Artificial (IBERAMIA), 2020-12) Villa Murillo, Adriana; Carrión García, Andrés; Sozzi, Antonio; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio[EN] We propose a methodology for the improvement of the parameter design that consists of the combination of Random Forest (RF) with Genetic Algorithms (GA) in 3 phases: normalization, modelling and optimization. The first phase corresponds to the previous preparation of the data set by using normalization functions. In the second phase, we designed a modelling scheme adjusted to multiple quality characteristics and we have called it Multivariate Random Forest (MRF) for the determination of the objective function. Finally, in the third phase, we obtained the optimal combination of parameter levels with the integration of properties of our modelling scheme and desirability functions in the establishment of the corresponding GA. Two illustrative cases allow us to compare and validate the virtues of our methodology versus other proposals involving Artificial Neural Networks (ANN) and Simulated Annealing (SA).
- PublicationMultivariate multinomial T2 control chart using fuzzy approach(Taylor & Francis: STM, Behavioural Science and Public Health Titles, 2015) Pastuizaca Fernández, María Nela; Carrión García, Andrés; Ruiz Barzola, Omar; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del CambioQuality of a product is often measured through various quality characteristics generally correlated. Multivariate control charts are a response to the need for quality control in such situations. If quality characteristics are qualitative, it sometimes happens that the product quality is defined by linguistic variables where quality levels are represented by some specific words and product units are classified into several linguistic forms categories, depending on the degree of fulfilment of expectations, creating a situation of fuzzy classifications. This study first reviews the concepts found in the literature on the development of fuzzy multivariate control charts. We propose a method to control these fuzzy quality evaluations, with correlated multiple attributes quality characteristics, through the use of a Hotelling T2 control chart.
- PublicationMonitoring of an aquatic environment in aquaculture using a MEWMA chart(Elsevier, 2019-01-18) Mulema, S. A.; Carrión García, Andrés; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio[EN] Monitoring an aquatic environment in aquaculture is usually carried out by controlling its physicochemical and biological parameters. The global state of the process is evaluated though the individual conditions shown in each parameter. However, the correlation structure in the data, caused by interdependence between these parameters, provides relevant information which must be controlled. Thus, the complex structure of the data requires a multivariate control method to explore both the individual and interactive effects of the environmental parameters. To achieve this goal, this paper presents a statistical method based on a Multivariate Exponentially Moving Average (MEWMA) chart to monitor the multivariate structure of an aquatic environment in aquaculture, especially in a crop of tilapia in Mozambique. The results show that the adjusted MEWMA chart is more consistent when controlling the conformity and stability of environmental parameters. Therefore, it can be considered an efficient statistical method to monitor an aquatic environment in aquaculture.
- PublicationStandards Development and Innovative Products. When should Standards be Prepared?(IJMEMS, 2019-10) Aronov, Joseph; Carrión García, Andrés; Papic, Ljubisa; Galkina, Nataliia; Aggrawal, Deepti; Anand, Adarsh; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio[EN] Usually, innovative products came to market with no standardization in their characteristics, resulting in frequent incompatibilities among similar products from different manufacturers. Thus, it is important to have standards available to industry as soon as possible. However, if standards are developed too early, maybe products finally do not succeed in the market and standardization efforts are lost, or maybe the technology continues evolving before it achieves some stability. If standards are developed too late, then probably their impact and usefulness for industry is much more limited. Basing in the adoption curve for innovative products, we formulated a proposal about the right moment to develop new standards for such products. To facilitate comparisons, we have defined an adequate common metric scale. This proposal has been verified by the analysis of some cases of innovative products, in which we have reviewed the adoption process and the starting of the standardization activity.
- PublicationThe variable sample size variable dimension T 2 control chart(Taylor & Francis, 2014-01-17) Aparisi García, Francisco José; Kahn Epprecht, Eugenio; Carrión García, Andrés; Ruiz Rivero, Omar José; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Escuela Técnica Superior de Ingeniería Industrial; Centro de Gestión de la Calidad y del Cambio; Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasil; Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, EcuadorIn this paper, we describe the development of the variable dimension and variable sample size T2 control chart (VSSVDT2), which is an enhancement of the variable dimension T2 chart (VDT2). In the VDT2 control chart, the number of variables that are measured to compute the T2 statistic is made variable. Some of the variables are easy or inexpensive to measure and are always monitored. The variables that are more difficult or expensive to measure are measured only when the T 2 value from the previous sample exceeds a specified threshold. The VDT2 control chart performs well for moderate and large shifts in the mean vector. However, its performance for small shifts is poor. To improve the charts performance in detecting such shifts, we propose the application of the variable sample size technique to the VDT2 control chart, resulting in the VSSVDT2 control chart. To promote the use of the VSSVDT 2 chart, a user-friendly software has been developed, which the final user can use to find the best parameters of the VSSVDT2 chart for a particular process. © 2013 Taylor and Francis.
- PublicationGuanajuato International Film Festival Visitor Profile and Segmentation(Sciendo, 2024-08-01) González Rosas, Erika Lourdes; Carrión García, Andrés; Navarrete Reynoso, Ramón; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio[EN] The purpose of the research was to know the profile of the attendees of the Guanajuato International Film Festival and to investigate whether there are differences between residents and visitors in terms of their motivations and types of events. The dimensions of production, family unity, exploration, escape, festival attractiveness, and experience were used for motivation. Attendance by event genre and sociodemographic variables (age, gender, residence, etc.) were also examined. The study consisted of administering 362 questionnaires to those attending festival events. This information was analysed to look for differences between strata using Student's t-test and Mann-Whitney tests. The results show that there were no significant differences between residents and non-residents, except in the festival attractiveness dimension which was higher for outsiders. Differences were found in visitors who attend some genres of events in terms of their behaviour as tourists. The uniformity of behaviour between residents and visitors confirms the importance of attendance, cohesion, and inclusion of the community that hosts the events and has a positive effect. The limitation of the study is the sample size. Additional research should address the analysis and evaluation of the costs and benefits of the festival.
- PublicationNumber of distinct data categories and gage repeatability and reproducibility. A double (but single) requirement(Elsevier, 2013-10) Carrión García, Andrés; Grisales Del Río, Ángela María; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio; Escuela Técnica Superior de Ingeniería InformáticaMeasurement systems analysis has been widely used in many industries, especially those related to the automotive sector as part of statistical process control practices. Over the years, new elements have been added to the initial requirements for system acceptance, centered on the values of repeatability and reproducibility (integrated in indexes as GRR and GRR%). One of these elements, the number of distinct data categories (NDC) has been treated as an independent requirement. In this paper, we show that NDC and GRR are not independent and that they are in fact both linked by an exact relationship. This therefore makes the double requirement redundant, confusing and unnecessary, except maybe to enhance some conceptual questions.
- PublicationA heuristic method for obtaining quasi ARL-unbiased p-Charts(John Wiley & Sons, 2019-02) Argoti, Marco Antonio; Carrión García, Andrés; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Centro de Gestión de la Calidad y del Cambio[EN] It is known that control charts based on equal tail probability limits are ARL biased when the distribution of the plotted statistic is skewed. This is the case for p¿Charts that serve to monitor processes on the basis of the binomial distribution. For the particular case of the standard three¿sigma Shewhart p¿Chart, which is built on the basis of the binomial to normal distribution approximation, this ARL¿biased condition is particularly severe, and it greatly affects its monitoring capability. Surprisingly, in spite of this, the standard p¿Chart is still widely used and taught. Through a literature search, it was identified that several, simple to use, improved alternative p¿Charts had been proposed over the years; however, at first instance, it was not possible to determine which of them was the best. In order to identify the alternative that excelled, an ARL performance comparison was carried out in terms of their ARL bias severity level (ARLBSL) and their In¿Control ARL (ARL0). The results showed that even the best performing alternative charts would often be ARL¿biased or have nonoptimal ARL0. To improve on the existing alternatives, the ¿Kmod p¿Chart¿ was developed; it offers easiness of use, superior ARL performance, and a simple and effective method for verifying its ARL¿bias condition.
- PublicationFurther Results on the Total Roman Domination in Graphs(MDPI AG, 2020-03) Cabrera Martínez, Abel; Cabrera García, Suitberto; Carrión García, Andrés; Dpto. de Ingeniería Electrónica; Facultad de Administración y Dirección de Empresas; Dpto. de Estadística e Investigación Operativa Aplicadas y Calidad; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Gestión de la Calidad y del Cambio; Grupo de Fenómenos Ondulatorios (GFO)[EN] Let G be a graph without isolated vertices. A function f:V(G)-> {0,1,2} is a total Roman dominating function on G if every vertex v is an element of V(G) for which f(v)=0 is adjacent to at least one vertex u is an element of V(G) such that f(u)=2 , and if the subgraph induced by the set {v is an element of V(G):f(v)>= 1} has no isolated vertices. The total Roman domination number of G, denoted gamma tR(G) , is the minimum weight omega (f)=Sigma v is an element of V(G)f(v) among all total Roman dominating functions f on G. In this article we obtain new tight lower and upper bounds for gamma tR(G) which improve the well-known bounds 2 gamma (G)<= gamma tR(G)<= 3 gamma (G) , where gamma (G) represents the classical domination number. In addition, we characterize the graphs that achieve equality in the previous lower bound and we give necessary conditions for the graphs which satisfy the equality in the upper bound above.