Cristóbal Vega

• PhD
• Research Director at University of Carabobo

Behavior graphs for controlling the production stages of a certain item are a useful tool for Statistical Process Control (SPC). The research proposed normalizing the variations that occur in the manufacturing of ketchup sauce due to the amount of water vapor added to the raw tomato sauce mixture. The methodology used consisted of examining the ste...

The efficiency of the different procedures carried out in a winery directly influences the quality of the wine, mainly in the stages that require control of the refrigeration temperature in order to ensure its correct manufacturing. The present work consisted of calculating the cold needs for a winery that handles a harvest of 100,000 kg for the pr...

La predicción desempeña un papel crucial en diversas actividades humanas, y el sector eléctrico no es una excepción. Tanto la toma de decisiones a largo plazo, como la planificación de la operación diaria, requieren de pronósticos precisos. En el caso particular de la energía eléctrica, actualmente su naturaleza no permite su almacenamiento a gran...

Presentación del Proyecto de Tesis de Maestría

El sesgo salarial de género, y la parte no explicada del sesgo entendido como discriminación, es un tema importante en la economía laboral. Durante las últimas décadas se han presentados varios métodos para la descomposición del sesgo salarial. Pero los procedimientos de estas desagregaciones no han satisfecho las necesidades de auditoría de las em...

Analytical arrangements based on quartz crystal microbalances are currently of great importance as they are techniques for the rapid qualitative or quantitative determination of chemical species, as well as allowing monitoring of the analysis in situ in real time. The present study presents the design and characterization of a rapid response measur...

Los arreglos analíticos basados en microbalanzas de cristal de cuarzo (quartz cristal microbalance) actualmente tienen gran importancia por tratarse de técnicas de determinación cualitativa o cuantitativa de especies químicas en forma rápida, además que permiten monitorear el análisis in situ a tiempo real. En el presente estudio se expone el diseñ...

One of the goals of engineering institutions is to organize and edit a scientific and technological dissemination body; a medium in which individual and group production of its members can finally be crystallized and that at the same time serves as an instrument of R+D+i exchange with other peers in the country and abroad. This article describes th...

Psoriasis is reemerging as a social problem in recent decades; for this reason, many recent studies have come out on this dermatological ailment in all its aspects. Formal studies with the appropriate statistical tools are increasingly necessary to verify the validity of these statements. This work proposes the use of time series to improve ongoing...

These notes present a basic overview of the most relevant aspects of the role of scientific journals in open science; for the review, the definition of open science established by the European Union forum is examined. The given concept covers many areas of academic society; furthermore, open science is supported by open data, open source, open acce...

The efficient editorial management of the manuscripts that are consigned to the scientific journals for review considers as a preliminary step the verification of their originality. A previously published writing or with a high percentage of paragraphs taken from other authors without the proper reference or the correct use of the "textual citation...

The goal of this paper is to obtain the consensus B-cell epitopes calculated from the spike glycoprotein of SARS-CoV, after an analysis of 946 epitopes predicted by thirteen different computer programs. To reduce and select the best epitopes, we define a function called that includes energy and structural factors obtained from the changes in the Gi...

This work aims to determine research trends, co-authors-country relations, and the structure of knowledge in the cocoa area worldwide through the bibliometric analysis; additionally mapping of the documents contained in the database of the main collection Web of Science for the period 2011-2016. Countries, research institutions, knowledge areas and...

The complexity of processes in the modern industry (many kinetics and fluid dynamic variables) makes to think in few data due to high costs for experimental data collection. Therefore, it is important to consider statistical models, such as the partial least square regression (PLSR) method that provide an adequate solution to the multicollinearity...

The germplasm banks are centers of conservation of biological material par excellence distributed worldwide, whose main objective is to preserve the biodiversity of species. They are guarantors of the rescue and conservation of food species, economically important and characteristic of each region. Theobroma Cocoa Germplasm Banks have been created...

The work of editing a journal requires a lot of dedication, it is a task that must be developed as a team and where the failure of any link in the chain affects the image of everyone. The numerous amount of aspects that can result in a rejected article, with severe, moderate or simple corrections obliges us to present a summary of the errors that a...

The La Bocaina Lagoon is a saltwater wetland of the Caribbean Sea, it is located in the San Esteban National Park, its hydrographic space is divided into two zones: coastal and deep, located in the Bay of Patanemo, place of great tourist affluence. The lagoon has presented notorious physical changes in its waters, as a result of the misuse and mana...

The origin of water from quality areas according to international standards empowers water to be fit for human consumption. The need to study natural reservoirs in the rainy and drought period has been observed in Venezuela, so the goal of this study is to evaluate the parameters related to chemical properties and organoleptic quality of surface wa...

For the models estimation study, the majority of researchers in statistics and economics sciences focus the methodology on project stages. Leave aside the epistemological aspects of their research. Therefore, this paper reviews current concepts of quantitative research without intervention. This work shows the importance of ex post facto research a...

Motivated by reading various scientific papers with serious details at fit by ordinary least squares, the author was to write this note. This note reviews and recommends several references for the ordinary least squares. The author then discusses procedures for model criterion selection, where he develops and recommends the selection of the model b...

El propósito del presente trabajo especial de grado es estimar modelos de series de tiempo que permiten simular la demanda de potencia eléctrica en Venezuela. La metodología usada es la de Box y Jenkins. Se ajustan modelos estacionales, auto regresivos, integrados y de media móvil (SARIMA) para estimar la demanda de potencia eléctrica del Sistema E...

This work plants a method of estimate of harmful in structure by no lineal signals separation, based in wavelet transform. The obtained results are superior in capacity of harmful estimate for reported in the literature. By system acceleration register and wavelet transform, the proposed method permits to estimate the instant and the amplitude of a...

Este trabajo presenta la s´ıntesis fenomenol´ogica y un modelo est´andar de las trombas marinas observadas en el Lago de Valencia, Lago de Maracaibo y en otras regiones de Venezuela, as´ı como los micro–tornados observados en el pa´ıs, su descripci´on matem´atica es determinada en t´erminos del Teorema de Kelvin y de la Ecuaci´on de Helmholtz para...

La metodología propuesta fue utilizada para determinar hidrocarburos aromáticos en muestras de agua potable provenientes de una zona sensible al riesgo por contaminación de estas especies. Se seleccionaron 52 muestras de agua de consumo humano mediante un diseño estadístico. Las muestras fueron sometidas a un tratamiento de extracción - preconcentr...

The proposed method was used to determine the concentration of aromatic hydrocarbons in samples of drinking water from a zone sensible to the contamination risk. 52 drinking water samples were selected by using a statistical design. A system of extraction - pre-concentration with a C 18 minicolumn was used for samples treatment and then they were a...

The contribution of this work is the creation and development of a novel procedure for signals estimation, procedure LDM-G. The procedure will be developed with details and will consist of algorithms implementation for signals estimation via wavelet transform, applying the minimum description length principle for simultaneous and automatic selectio...

Cancer is one of the main causes of death in the world. It is defined as an emergent disease because is associated to some other factor, and considered re-emergent because of its epidemic-endemic presentation; 80% of cases are associated to environmental factors; this fact has been linked to the geographic location of the population under risk. The...

El propósito de este trabajo es emplear y adaptar algunas herramientas estadísticos para luego aplicarlo a la data que se han ido recolectando a través de los años; dado que la recolección de dicha data dependen de instrumentos de medición de cada uno de los elementos meteorológica, éstas pueden producir impurezas o hasta podría faltar datos por re...

Un review de las herramientas que se emplean para la recolección de los datos meteorológicos, sus parámetros y los tipos de datos en que se almacena. Las ubicaciones geográficas de las 36 estaciones de recolección de datos meteorológicas en Venezuela.

A procedure for efficient denoising of piezoelectric signals based on the combined use of two mathematical approaches, viz. the minimum description length principle and the garrote shrinkage technique (MDL–garrote), was developed with a view to improving the accuracy and precision of the results provided by piezoelectric sensors as well as determin...