Repositorio Universidad Simón Bolívar
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Cluster competitiveness modeling: approach with systems dynamics
This study makes a systemic review to cluster and create a competitiveness relationship
considering a systems dynamics approach. A dynamic hypothesis was constructed to validate
what factors increase a cluster’s level of competitiveness, through causal analysis. Then, the causal
diagram that validates the dynamic H0 hypothesis was constructed in Vensim PLE systems®.
Literature review shows the evolution of the cluster system according to the current needs of the
market, and emphasizes the need for new approaches and models that capture the complexity and
dynamics of this system, allowing the understanding of its structure and the evaluation of the
contribution of factors and capabilities to cluster competitiveness. It highlights the usefulness of
systems dynamics as a simulation methodology for dynamic and complex systems, and establishes
itself as a growing line of research applied to various systems of study. Dynamic hypothesis H0
was validated using the causal diagram, reaching the conclusion that innovation, productive
management, financial management, organizational management, commercial management, and
cluster management factors positively increase the cluster competitiveness level. From structure
analysis, the behavior is associated to the archetype “Path Dependence,” usual in growing
industrial markets
Big Data and automatic detection of topics: Social network texts
This paper proposes the analysis of the influence of terms that express feelings in the
automatic detection of topics in social networks. This proposal uses an ontology-based
methodology which incorporates the ability to identify and eliminate those terms that present a
sentimental orientation in social network texts, which can negatively influence the detection of
topics. To this end, two resources were used to analyze feelings in order to detect these terms.
The proposed system was evaluated with real data sets from the Twitter and Facebook social
networks in English and Spanish respectively, demonstrating in both cases the influence of
sentimentally oriented terms in the detection of topics in social network texts
Behavioral aspects of phlebotomine sand flies associated with a case of cutaneous leishmaniasis in Atlántico, northern Colombia
After the first autochthonous case of cutaneous leishmaniasis was reported in the Atlántico department in the Caribbean region of Colombia, entomological sampling was conducted in the specific areas where the infection might have occurred. CDC traps were installed inside and outside dwellings in the peri-urban and rural areas of a settlement in the municipality of Luruaco. Sampling was performed during the night with protected human bait, and phlebotomine sand flies were actively sampled from potential diurnal resting sites within dwellings. Ten species of the genus Lutzomyia were identified; Lutzomyia evansi was the dominant species (78%) in the rural and peri-urban areas as well as in the different sampled habitats, followed by Lutzomyia panamensis and Lutzomyia gomezi. There was a 100% household infestation by Lu. evansi, and its indoor mean abundance was 13.3 sand flies/CDC trap/night. The indoor mean abundance of Lu. panamensis and Lu. gomezi was only 0.9 and 0.8 sand flies/CDC trap/night, respectively. Female Lu. evansi were collected with protected human bait, mostly in the peridomestic area, with sustained activity during the night and a slight increase in the activity from 19:00 to 23:00 hours. Of the total sand flies captured in the diurnal resting sites, 73.1% were collected from the walls of bedrooms and corresponded to Lu. evansi, Lutzomyia cayennensis cayennensis, and Lutzomyia trinidadensis. Owing to their vectorial importance, the species on which entomological surveillance should be focused are Lu. evansi, Lu. panamensis, and Lu. gomezi. The biting and resting behavior reported in this study will help guide vector prevention and the control of leishmaniasis within the study area
Artificial intelligence assisted Mid-infrared laser spectroscopy in situ detection of petroleum in soils
A simple, remote-sensed method of detection of traces of petroleum in soil combining
artificial intelligence (AI) with mid-infrared (MIR) laser spectroscopy is presented. A portable MIR
quantum cascade laser (QCL) was used as an excitation source, making the technique amenable to
field applications. The MIR spectral region is more informative and useful than the near IR region for
the detection of pollutants in soil. Remote sensing, coupled with a support vector machine (SVM)
algorithm, was used to accurately identify the presence/absence of traces of petroleum in soil mixtures.
Chemometrics tools such as principal component analysis (PCA), partial least square-discriminant
analysis (PLS-DA), and SVM demonstrated the e ectiveness of rapidly di erentiating between
di erent soil types and detecting the presence of petroleum traces in di erent soil matrices such as
sea sand, red soil, and brown soil. Comparisons between results of PLS-DA and SVM were based
on sensitivity, selectivity, and areas under receiver-operator curves (ROC). An innovative statistical
analysis method of calculating limits of detection (LOD) and limits of decision (LD) from fits of the
probability of detection was developed. Results for QCL/PLS-DA models achieved LOD and LD
of 0.2% and 0.01% for petroleum/soil, respectively. The superior performance of QCL/SVM models
improved these values to 0.04% and 0.003%, respectively, providing better identification probability
of soils contaminated with petroleum
Neural networks for tea leaf classification
The process of classification of the raw material, is one of the most important
procedures in any tea dryer, being responsible for ensuring a good quality of the final product.
Currently, this process in most tea processing companies is usually handled by an expert, who
performs the work manually and at his own discretion, which has a number of associated
drawbacks. In this work, a solution is proposed that includes the planting, design, development
and testing of a prototype that is able to correctly classify photographs corresponding to samples
of raw material arrived at a dryer, using intelligence techniques (IA) type supervised for
Classification by Artificial Neural Networks and not supervised with K-means Grouping for
class preparation. The prototype performed well and is a reliable tool for classifying the raw
material slammed into tea dryers
Interaction with soil bacteria affects the growth and amino acid content of piriformospora indica
Exploration of the e ect of soil bacteria on growth and metabolism of beneficial root
endophytic fungi is relevant to promote favorable associations between microorganisms of the plant
rhizosphere. Hence, the interaction between the plant-growth-promoting fungus Piriformospora indica
and di erent soil bacteria was investigated. The parameters studied were fungal growth and its
amino acid composition during the interaction. Fungus and bacteria were confronted in dual
cultures in Petri dishes, either through agar or separated by a Perspex wall that only allowed the
bacterial volatiles to be e ective. Fungal growth was stimulated by Azotobacter chroococcum, whereas
Streptomyces anulatus AcH 1003 inhibited it and Streptomyces sp. Nov AcH 505 had no e ect. To analyze
amino acid concentration data, targeted metabolomics was implemented under supervised analysis
according to fungal-bacteria interaction and time. Orthogonal partial least squares-discriminant
analysis (OPLS-DA) model clearly discriminated P. indica–A. chroococcum and P. indica–S. anulatus
interactions, according to the respective score plot in comparison to the control. The most observable
responses were in the glutamine and alanine size groups: While Streptomyces AcH 1003 increased the
amount of glutamine, A. chroococcum decreased it. The fungal growth and the increase of alanine
content might be associated with the assimilation of nitrogen in the presence of glucose as a carbon
source. The N-fixing bacterium A. chroococcum should stimulate fungal amino acid metabolism via
glutamine synthetase-glutamate synthase (GS-GOGAT). The data pointed to a stimulated glycolytic
activity in the fungus observed by the accumulation of alanine, possibly via alanine aminotransferase.
The responses toward the growth-inhibiting Streptomyces AcH 1003 suggest an (oxidative) stress
response of the fungus
Knowledge on prevention of sexual transmission infections in inmigrant adolescents in Soledad Atlantico 2018-2019
Durante los últimos años ha incrementado el interés en el estudio de la adolescencia y el debut de las relaciones sexuales y de
pareja que presentan con frecuencia malestares de la salud sexual y reproductiva, que se manifiesta en el incremento de las
infecciones de transmisión sexual y embarazos no deseados. A su vez la problemática por el fenómeno de migración hace que
en la mayoría de casos esta población tenga difícil acceso a una institución de salud, lo que no permite tener un diagnóstico
precoz y tratamiento oportuno este trabajo tiene como objetivo evaluar el conocimiento sobre prevención de infecciones de
transmisión sexual en adolescentes inmigrantes habitantes en Soledad-Atlántico 2018-2019. Se utilizó una metodología
cuantitativa con enfoque descriptivo cuantitativo, la población objeto de estudio fueron 234 adolescentes inmigrantes que en
el rango de 10-19 años y que accedían a los servicios en salud en institución pública de Soledad-Atlántico. Se logró deducir a
través de la encuesta el conocimiento que tienen las adolescentes sobre infecciones de transmisión sexual, el resultado indica
que el nivel de conocimiento es medio, y afirman que es de gran importancia que los jóvenes adquieran conocimiento sobre las
ITS. Es apremiante la educación a la población vulnerable como método de prevención y aporte a la salud con énfasis en el
fortalecimiento de la Educación Integral de la Sexualidad a través de la promoción de conductas sexuales saludables.In recent years, interest in the study of adolescence and the debut of sexual and couple relationships that frequently present
sexual and reproductive health discomforts, which is manifested in the increase in sexually transmitted infections and
pregnancies, have increased not wanted. At the same time, the problem caused by the phenomenon of migration means that in
most cases this population has difficult access to a health institution, which does not allow for early diagnosis and timely
treatment. This work aims to assess the knowledge about prevention of sexually transmitted infections in immigrant
adolescents living in Soledad-Atlántico 2018-2019. A quantitative methodology with a quantitative descriptive approach was
used, the population under study were 234 immigrant adolescents in the range of 10-19 years and accessing health services at
a public institution in Soledad-Atlántico. It was possible to deduce through the survey the knowledge that adolescents have
about sexually transmitted infections, the result indicates that the level of knowledge is medium, and they affirm that it is of
great importance that young people acquire knowledge about STIs. Education to the vulnerable population is urgent as a
method of prevention and contribution to health with emphasis on strengthening the Integral Education of Sexuality through
the promotion of healthy sexual behaviors
Natural language explanation model for decision trees
This study describes a model of explanations in natural language for classification
decision trees. The explanations include global aspects of the classifier and local aspects of the
classification of a particular instance. The proposal is implemented in the ExpliClas open source
Web service [1], which in its current version operates on trees built with Weka and data sets with
numerical attributes. The feasibility of the proposal is illustrated with two example cases, where
the detailed explanation of the respective classification trees is shown
Forecasting electric load demand through advanced statistical techniques
Traditional forecasting models have been widely used for decision-making in production, finance and energy. Such is the case of the ARIMA models, developed in the 1970s
by George Box and Gwilym Jenkins [1], which incorporate characteristics of the past models of the same series, according to their autocorrelation. This work compares advanced statistical methods for determining the demand for electricity in Colombia, including the SARIMA,
econometric and Bayesian methods
Economic order quantity for perishables with decreasing willingness to purchase during their life cycle
In an inventory management model for perishables, depletion due to interacting with the demand is of importance, but also, damage to products is a relevant
variable. This article considers that demand and sales phenomena do not always go hand-in-hand. The demand process relates to the willingness to acquire products
in good condition, giving the customer the power to evaluate the quality of the product before an effective purchase takes place. We also considered the cost of
disposing of unsold units, besides the conventional costs for storage and procurement. We then proposed a mathematical model to derive the Economic
Order Quantity (EOQ) under specific conditions, in order to minimize the expected management cost of perishables, assuming constant demand and linearly
decreasing purchase probability during the product life cycle. We proposed several random instances and validate the mathematical model using simulation. We then
found the optimal parameters for the inventory policy using a third-order numerical approximation. Last, we developed a sensitivity analysis over the product life cycle to prove that the proposed model approximates to a traditional EOQ model for perishables when life cycle is sufficiently large