bluuebunny/crossref_metadata_2025_split huggingface dataset:
“Hero, genius, king and Messiah”
Authors: Shukrun-Nagar Pnina 
Published: June 2020

This paper discusses readers’ comments on posts written by the Israeli Prime
Minister Benjamin Netanyahu on his Facebook page in November 2017. It focuses on the
use of ironic echoes (Sperber & Wilson
1981) of compliments and accusations, including multi-stage ones, to either enhance or damage Netanyahu’s ethos as a successful
leader.
It is argued that Netanyahu’s supporters use ironic echoes of accusations by his critics in order to
enhance his ethos, whereas his critics use ironic echoes of compliments to Netanyahu in order to damage it. Moreover, It is argued that both the construction
and de-construction of Netanyahu’s ethos are intertwined with the self-enhancement
of the positive face (Brown & Levinson
1987) of commenters from one political camp, alongside the threat to the
positive face of their rivals.
Portable robotic telescope for the teaching of solar astronomy
Authors: González Pérez J M , Arceo Díaz S , Bricio Barrios E E , Ortega Valencia J C , Pineda Ortega J A , Moreno Peña J R 
Published: June 2020

Abstract
This work describes a prototype of a miniature robotic telescope, with the didactic purpose of the teaching of solar astronomy, Arduino programming and basic control theory. The telescope is made from low cost components: a 3D printed base that supports a commercial lens (typically used for bird watching and covered with a white-light solar filter). The system is guided by a program that uses the amount of light collected by a set of four light detecting resistors as an input signal to rotate a pair of small stepper motors, pointing the lens towards the Sun. A simple control scheme is implemented for ensuring that the image of the Sun is centered within the frame. The images and video captures of the Sun is collected by a small photographic camera and uploaded to a website.
Development and implementation of a predictive method for the stock market analysis, using the long short-term memory machine learning method
Authors: Pedrozo D , Barajas F , Estupiñán A , Cristiano K L , Triana D A 
Published: June 2020

Abstract
In this work, the development and implementation of a computational tool based on the Long Short-Term Memory method were showed. The code was written in python, and consist of a recurrent neural network used in the field of deep learning. In the code, we implement artificial intelligence, which uses linear and logistic regression to make a predictive analysis based on historical data of each foreign exchange and the stock prices, with the target of predicting the next point of the future price (the price of closing of the futures trading candlestick). Cross-validation between linear and logistic regression is also performed to see which of the two has the highest success rate, that is, the accuracy of the method is evaluated using two validation alternatives. In addition, we make a matrix of pairs of different foreign exchanges to identify which are the most correlated or inverse, so that the program can open its range of operations (simultaneously with different foreign exchange), and with this, a greater number of operations can be made per time established (in the foreign exchange case it is from one minute to five minutes, operations strategy is called scalping). Finally, we present the results obtained, based on the behavior of foreign exchange and stock prices, using a statistical predictive to assess the accuracy of said sample statistical model taken in this study.
Characterization of inertial sensors signals of a smartwatch during walking
Authors: Montero D , Salinas S , Laverde G , Sotelo S , Rueda C , Altuve M 
Published: June 2020

Abstract
Parameters of the human gait cycle are commonly used for the evaluation and diagnosis of motor and neurological disorders. Traditionally, biomechanical analysis is performed in specialized laboratories, but in these locations, the subject does not perform a natural gait and tends to hide or exaggerate their alterations. Therefore, in this paper, we characterized eighteen signals per experiment: six from gyroscopes and six from accelerometers of a smartwatch (Apple Watch Series 3) worn on each wrist, and three from gyroscopes of an inertial sensors placed on the ankles. Signals were collected from twenty young and healthy subjects without pathological history. Subjects walked naturally in a straight-line for 25 meters. Each subject performed the walking cycle several times for 6 minutes, 3600 signals were thus analyzed. Each signal was characterized using time domain, frequency domain and nonlinear measurements. Results show that angular velocity in the Z-axis contains relevant information to characterize human gait in both ankles and the wrist. Also, typical gait parameters were obtained from the smartwatch signals. The sample entropy showed that signals that have greater self-similarity are those that contain more information, such as angular velocity signals on the Z-axis in each ankle and wrist. This characterization could be useful for the automatic identification of the human gait cycle, the detection of pathologies and the recognition of people from human gait patterns using only the information extracted from sensors embedded in smartphones and smartwatches.
Bifurcation calculation in population chaotic dynamics
Authors: Figueroa W , Prada D , Gomez J 
Published: June 2020

Abstract
Chaotic population dynamics present interesting behaviors that are the object of study for biologists, microbiologists, ecologists, epidemiologists and bioanalysts. With the proposal of the mathematician and biologist Pierre Verhulst on the logistic equation as a population discrete mathematical model, studies were initiated on chaotic dynamics regarding the growth factor immersed in the equation. When assigning different values to the factor, orbits are observed that are initially convergent, however, there are values for which there is no convergence due to the bifurcations suffered by the orbit. For values greater than or equal to 3 and less than 4, the forks bend, but not consecutively. Through the logistic equation and the identity function it is possible to find the values of the orbit corresponding to a specific value of the growth factor, however, these data are evidenced graphically, so it is important to know the explicit calculation of these bifurcations. The calculation of the fixed points of the quadratic iterator of the logistic equation is shown by equations.
Differential equations with natural matrices coefficients
Authors: Acosta-Humánez P , Ramírez-López J 
Published: June 2020

Abstract
In this paper we present the main results of the master thesis in applied mathematics of the second named author, which was supervised by the first named author. Such results, and for instance this paper, concerns to some differential and algebraic results involving natural matrices. The problem of solving differential equations is very ancient and is very important to get explicit solutions of differential equations to be applied in physics and other areas. In this paper, as well in the master thesis, we study the differential and algebraic structure of linear differential equations with natural matrix coefficients and generalizations. These results are original and important for researchers interested in differential algebra and applications of differential equations.
Fractal analysis of the time series of particulate material
Authors: Prada D A , Parra D , Tarazona J D , Silva M F , Vera P , Montoya S , Acevedo A , Gomez J 
Published: June 2020

Abstract
The air quality index shows the pollution of the air we breathe, a very low index indicates that we can have respiratory, eye or heart conditions. An index below the minimum levels declared, requires generating strategies such as days without the presence of private vehicles, among others, to reduce pollution. The city of Medellin, Colombia, has shown very low levels in the air quality index due to several factors, mainly the emission produced by vehicles and companies. Due to this, activities have been initiated to reduce the emission of 2.5 micron and 10 microns particulate material, classified as highly harmful to health. The city installed 12 air quality monitoring stations and designed a decontamination proposal for the year 2030. Conducting a study on the persistence of particulate matter in the air according to the data recorded by the stations, will strengthen the proposed strategy or modify it to achieve the goal. In this work, the data collected by a station from July to December 2018 in which a high persistence in the presence of particulate material was analyzed.
Making decisions with implications networks: Methodology and examples
Authors: Redondo J M , Bustamante-Zamudio C 
Published: June 2020

Abstract
The effect of implementation of policies, programs, plans and projects on the social, economic and environmental aspects of landscapes responds to conditioning factors that give a degree of sensitivity to these landscapes. The objective of this paper is to propose a landscape analysis methodology that allows to identify guidelines and priorities for landscape management. We have called this methodology the implications networks and it is based on chains of cause-effect relationships, in which the direct, indirect and cumulative (additive or synergistic) implications of the different types of actions on landscapes are considered. This methodology has been used in Colombia to establish the socio-environmental sensitivity of landscapes to the plans for the expansion of electric transmission, nature tourism, the moving of hydrocarbons by pipelines and wagons, demonstrating their usefulness and relevance for making decisions in these sectors, as well as to analyze the incidence of land use policies in Andean landscapes. The experience gained from the implementation of the implications networks methodology allows us to conclude that this is a useful and versatile systemic analysis tool to conduct studies and establish guidelines for the integral management of territories with multiple landscape units and various socio-environmental conditions.
Relevance of the mathematics teacher’s specialized knowledge model in the planning and interpretation processes at the spatial thinking
Authors: Acevedo-Rincon J P 
Published: June 2020

AbstractWhen analyzing the relationships between knowledge and the teacher, some relationships related to the planning of teaching practices during professional practice are identified. One of the known reasons for these knowledge needs in planning is the lack of recognition of other elements in school mathematics. Under the theoretical perspective of the model of the specialized knowledge of the teacher who teaches mathematics, this qualitative research aims to characterize the elements of specialized knowledge in a geometry class and the subsequent reflection of the tasks of planning teaching. Among the main results of this research show the need to deepen the knowledge of the “basic” concepts of geometry, such as the cube, its characteristics and its representation from different perspectives. Therefore, it is necessary to motivate in teachers the need to develop their own spatial visualization skills, so that they apply them to the school mathematics they teach in their daily lives.
Dynamic geometry and square of the circle in Thomas Hobbes
Authors: Flórez-Pabón C E 
Published: June 2020

AbstractThis paper aims to present the reconstruction of the arguments offered by Thomas Hobbes about the classic problem of the squareness of the circle in the seventeenth century, from the perspective of the work: De Corpore of the same author. Where research is based on the support offered by Dynamic Geometry in the 21stcentury in the classroom with the use of GeoGebra software. This to be able to address and overcome the problems of the history of mathematical science and philosophy. For this it was chosen, by the methodology of a design of a teaching experiment in the classroom carried out with future teachers of the bachelor’s degree in mathematics of 8thsemester. Among the most important results is the recognition of renowned philosophers in the development of the history of mathematics. This implied that prospective mathematics teachers had to integrate their mathematical knowledge into the construction of the quadrature of the circle, which at the time was a problem for Hobbes, but with the perspective of modeling mathematical concepts in dynamic geometry, today it is done efficiently.
Factors that promote positive attitudes towards mathematics in higher education students
Authors: Orozco-Guzmán M , Villanueva-Cantillo J , Mejía Acuña F , Castro S Obredor , Malo E Silvera 
Published: June 2020

AbstractThe purpose of this review article is to explain the importance of understanding attitudes towards teaching and learning mathematics in higher education students. For that, we start from the premise that attitudes are related to performance towards learning mathematics, bearing in mind that what directly influences their success are the feelings of possessing competencies to understand their contents and not the feelings of difficulty towards them. In essence, at first, we describe the different attitudes towards mathematics. Next, we examine how attitudes influence math learning and finally identify the factors that foster positive attitudes toward math. From this, we suggest teaching practices that can be carried out to foster positive attitudes towards mathematics and propose new lines of research in this field.
Nuances of the philosophy of mathematics
Authors: Flórez-Pabón C E 
Published: June 2020

Abstract
Historically, the term philosophy of mathematical education is associated with the term philosophy of mathematics. However, mathematics as a mathematical education has its own foundations, schools, currents, and authors. Thus, it is possible to visualize from different research that one’s own research with foundations in the philosophy of mathematics is stronger than in the philosophy of mathematical education. In order to base the present research on the philosophy of mathematics education, we have made use of a mixed method, which involves a quantitative analysis of the references made in Scopus databases through their search algorithms, in addition to a qualitative design under the contributions of the onto-semiotic approach and the Kantian synthetic analysis. When trying to particularize the identity of the philosophy of mathematical education as an area of research in development, it is evident among the main approaches: (i) the identity process of the philosophy of mathematical education is still under construction; and, (ii) recognize the decoloniality of mathematical knowledge, imposed for centuries by Western mathematics, and backed by a single philosophy of mathematics.
Pedagogical practice and academic performance in mathematical processes: A descriptive - correlational analysis
Authors: Hernández Suarez C A , Fernández Cèzar R , Prada Nuñez R 
Published: June 2020

Abstract
This report has aimed to analyze students ‘perceptions of pedagogical practice in teachers’ mathematical processes and analyze the link with their academic performance. The methodology used is quantitative, articulated with two study analyses, descriptive and correlational, under a non-experimental, correlational-causal cross-sectional design, since it seeks to explain the relationship between the variables. The technique used for data collection was a structured questionnaire, of 47 questions of the Likert Scale type, which was applied to 103 students of the basic education level, belonging to an educational institution located in the “Departamento del Norte de Santander, Colombia”, selected by non-probabilistic sampling This instrument was subjected to the respective analyses that determined its validity and reliability. For the academic performance the average of the accumulated grades obtained at the end of the third academic period, year 2019, was used. The results show that the pedagogical practices on the mathematical processes implemented by the teachers, from the perspective of the students, are a factor in the academic performance of that area.
The proper motion of sunspots umbra in the rising phase of Cycle 24
Authors: Permata K , Herdiwijaya D 
Published: June 2020

Abstract
The differential rotation is the difference in the rate of rotation of each latitude in the Sun indicating that the Sun is not a solid body. The differential rotation is the result of the interaction between rotation and convection and causes dynamo circulation that affects the cycle of solar activity. In this research, we measured the coordinates of 304 sunspots umbra as tracer in the rising phase of the Solar Cycle 24 to obtain the differential rotation equation. Coordinates of sunspots were measured using AIA images at a wavelength of 4500 Å from SDO (Solar Dynamic Observatory) with JHelioviewer software. The areas of sunspots were measured using HMI (Helioseismic Magnetic Imager) images with ImageJ software. From the measurement, we derived the differential rotation equation and the relation of sidereal rotation and area of sunspots umbra. The differential rotation equation obtained in this research is ω(B) = (14.27 ± 0.01) - (0.78 ± 0.10) sin2B (°/day). There is a difference between the differential rotation equation of the northern and southern hemispheres that indicates the asymmetry between different hemispheres. We got the sidereal rotation of sunspots with area < 5 MH is 0.70% higher than sunspots with area > 15 MH.
Extinction and scattering parameters derived from sky brightness measurements
Authors: Priyatikanto Rhorom 
Published: June 2020

Abstract
In this study, the moonlit sky brightness model that incorporates extinction and scattering parameters were fitted to the observational data obtained at four locations across Indonesia namely Biak, Garut, Pasuruan and Sumedang. Possible parameters were sampled using Markov Chain Monte Carlo to construct posterior distributions of corresponding parameters. The typical values of extinction parameter are below 0.5 except for Pasuruan whose value almost reaches unity. Atmospheric scattering is represented by Rayleigh scattering factors with values of around 1.0 and Mie scattering factors which are an order magnitude higher than Rayleigh scattering factors. The results indicate that the tropical atmosphere of Indonesia tends to be more turbid than the atmosphere at higher latitudes though more studies are required to confirm this indication.
Pc5 ULF waves during the geomagnetic storms on 7–8 September 2017 observed in the Indonesian region
Authors: Pranoto S C , Musafar L M , Singarimbun A , Srigutomo W 
Published: June 2020

Abstract
Pc5 ULF waves have attracted significant attention and been studied through theory, simulation, and observations. To understand the generation mechanisms of ULF waves, one should consider frequency characteristics, solar wind parameters, and geomagnetic activity. Observation on Pc5 magnetic pulsations due to solar wind perturbations at the low latitudes currently has not been widely explored. In this paper, we analyzed the amplitude of Pc5 magnetic pulsations during magnetic storms on 7–8 September 2017. We also investigated the effect of shock in the solar wind on the amplitude of Pc5 magnetic pulsation. We used the magnetometer data of four stations in the Indonesian region, which is located at low latitude, the ACE satellite data, and the Dst index. To extract Pc5 magnetic pulsations, we used the second-order of Butterworth filter with applying the Hamming windowing method. The result shows that the fluctuation in solar wind dynamic pressure triggers the Pc5 pulsations with similar waveforms and the same phase in both components of H and D. Large southward Bz component of the interplanetary magnetic field accompanied by the increase of solar wind dynamic pressure caused the large and long duration of Pc5 pulsation.
Dispersion of Irregular Particles during Free Fall
Authors: Fadzir A.F.M. , Rani S.I. , Gimbun J. 
Published: June 2020

Abstract
This paper describes an experimental set up to examine the relationship between powder properties on powder flow pattern during filling operation. For this purpose, the free fall velocities of four types of agricultural dusts (i.e. castor sugar, oat, semolina and tea powder) in a rectangular enclosure were captured using a Particle Image Velocimetry (PIV). The result reveals that oat powder portrayed greater cloud dispersion due to its flaky shape and a lower bulk density. The characteristics of oat powder allowed more air to be dragged into the particle stream and forced the particle to be dispersed and suspended in air due to drag force and terminal velocity. The result presented here may facilitate improvements in dust control and measures in powder industries.
The Effect of Blending Methods on the Properties of PLA/Gr Nanocomposites
Authors: Hashim N. , Amin N.R.B. , Abdullah S. , Abdullah A.H. , Abdullah N. , Mohamed R.M. , Yahya N.A.M. , Yusoh K. 
Published: June 2020

Abstract
Polymer nanocomposites based on polylactic acid (PLA) and graphene (Gr) were blended via melt blending and solution mixing. The properties of hardness and melt flow index (MFI) were investigated with variables of Gr loading from 0.5–2.0 wt.% and the effect of poly(ethylene glycol) (PEG) as plasticizer. The PLA/Gr nanocomposites exhibited higher hardness compared with neat PLA for both methods of nanocomposites preparation which were due to stiffness effect from nanofiller. The loading of PEG in the PLA nanocomposites resulted in the slightly decreasing of hardness. The hardness of PLA and PLA nanocomposites obtained from melt blending were higher than hardness from solution mixing where 2.0 wt.% Gr loading in PLA exhibited maximum value which was 83.1 Shore D. The significant improvement on the MFI could be seen with plasticizer loading compared to unfillled PEG in PLA blends obtained from both methods. Again, the MFI values of PLA/Gr showed from melt blending were higher than exhibited from solution blending method. The highest MFI was 70.6 g/10 min, obtained from 0.5 wt.% Gr loading in PLA/PEG/Gr nanocomposite. The morphology study from Field Emission Scanning Electron Microscopy (FESEM) analysis confirmed the interfacial interaction and homogeneity of Gr in PLA in order to enhance the hardness and MFI properties as discussed above.
The Electrical Performance of Microvaristor Composites at Different Filler Loadings
Authors: Ahmad H. , Ismail H.A. , Haddad A. 
Published: June 2020

Abstract
Resistive field grading materials is deliberately gaining attention since it shows better performance in steering uniformly electrical properties of high voltage equipment compared to conventional machinery techniques. The key point of these extraordinary materials because its electrical properties that can be tuneable according to material characteristics, composition of chemical elements in the host matrix and significantly influenced from fabrication process. In this research, microvaristor composite was added with silicone rubber at different weight percentage (wt. %) with dimension 50 mm x 50 mm x 5 mm. The selection of this material because it is more robust and less sensitive to a variety parameters such as pressure and humidity. The samples were examined under power frequency voltage at 50 Hz. The experimental results were analysed using Point on Wave (POW) technique and electrical properties for all samples were evaluated at highest applied voltage, 5 kV.