bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced ambient signals based load model parameter identification with ensemble learning initialisation
Authors: Zhang Xinran , Hill David J. , Zhu Lipeng
Published: June 2020

Load modelling is significant to ensure the accuracy of power system simulation. In previous research on load modelling, various optimisation algorithms have been widely applied. However, the achievement of the global optimal solution depends on the quality of the initial feasible solutions (IFSs). In this study, an enhanced measurement‐based load modelling approach with ensemble learning‐based initialisation is proposed to solve this problem. In the proposed method, an ensemble intelligent machine (EIM) is trained offline to provide high‐quality IFSs based on which the load model parameters can be identified through optimisation. The input features of the EIM are extracted through numerical subspace state‐space system identification from the measurement data, while the output of the EIM is the estimated load model parameters. Then, based on the offline generated samples, a group of individual intelligent units (IIUs) is trained and selected first, after which they are integrated to form an EIM. The enhanced load modelling approach is tested in a simulation case for the Guangdong power grid. The results show that the EIM has better performance than all the IIUs, and the identification accuracy of the load model parameters can be improved with the EIM estimated parameters as the IFSs.
Design of a substrate‐integrated waveguide based slot‐pair array antenna for bandwidth enhancement
Authors: Zhao Renrong , Liu Bing , Ma Yu , Xing Wenqiang , Sun Xingkai
Published: June 2020

This study proposes a novel radiating element to enhance the bandwidth of a substrate‐integrated waveguide‐based resonant slot array antenna. Unlike the conventional scheme, the proposed element has two parallel slots of unequal length. The long slot dominates the radiation, while the short one deals with the matching. An amplitude‐tapering power divider was integrated into a element array to restrain the E‐plane sidelobe level (SLL). The measured ‐dB bandwidth is 23.14–25.4 GHz (9.42% @24 GHz). The E‐plane and H‐plane SLLs are 22.04 and 30.34 dB, respectively. The cross‐polarised levels in the operating band are 30 dB and a peak gain of 17.77 dBi was measured at 24.2 GHz. A good agreement is observed between the simulated and measured results and then validates the feasibility of the bandwidth‐enhanced slot pair proposed herein.
Design of class‐EM amplifier with consideration of parasitic non‐linear capacitances and on‐state resistance
Authors: Abbasi Hamed , Hayati Mohsen , Kazimierczuk Marian K. , Sekiya Hiroo
Published: June 2020

In this study, the design of the class‐EM­ power amplifier is presented. In this design, the effects of on‐state resistance and non‐linear parasitic capacitances of the transistors are investigated. Two metal oxide semiconductor field‐effect transistors (MOSFETs) of IRFZ24N and IRF510 with different drain‐source resistances are used in the presented circuits. In the given design, the values of the operational frequency and duty ratio are 3.5 MHz and 0.5, respectively. This study shows the importance of considering non‐linear parasitic elements of MOSFET, especially drain‐source resistance in the designing of the class‐EM power amplifiers. It is shown that the class‐EM power amplifier with high MOSFET drain‐source resistance needs high DC input voltage for both the primary and auxiliary circuits. In the previous works, non‐linear on‐state resistance and non‐linear drain‐source and gate‐drain capacitances have not been included at the same time in the analyses. Two class‐EM amplifiers contain IRF510 and IRFZ24N are designed, simulated, and measured. The efficiency equal to 96.6% with 11.851 W output power at 3.5 MHz and the efficiency equal to 88.4% with 12.361 W output power are achieved for presented class‐EM amplifiers contain IRFZ24N and IRF510, respectively.
Robust optimisation framework for SCED problem in mixed AC‐HVDC power systems with wind uncertainty
Authors: Dehghani Filabadi Milad , Pirooz Azad Sahar
Published: June 2020

Wind power uncertainties have made the large integration of wind power generating units in the power system highly challenging. One promising solution to overcome the challenges associated with the intermittency of the renewable energy resources (RESs) is to connect areas with diverse renewable energy portfolios via high voltage direct current (HVDC) transmission lines with controllable power transfer capability. The installation of HVDC transmission lines in the power system has resulted in the evolution of conventional alternating current (AC) networks to mixed AC‐HVDC power systems. In this study, to address wind power uncertainties in mixed AC‐HVDC multi‐area power systems, a modified robust optimisation (RO) model for the security‐constrained economic dispatch (SCED) problem is proposed. The proposed RO model is used to minimise the generation cost and wind power curtailment under the worst‐case scenario of actual wind power. Unlike the existing RO models, the proposed RO model considers a modified uncertainty set based on the wind power admissibility and addresses the budget of uncertainty more accurately to adjust the solution's level of conservatism. Extensive numerical studies demonstrate the economic and operational advantages of the proposed RO model for solving the SCED problem in mixed AC‐HVDC power systems with high penetration of RESs.
Erstlinientherapie des behandlungsbedürftigen Multiplen Myeloms – Aktuelle Empfehlungen
Authors: John Lukas , Goldschmidt Hartmut , Scheid Christof
Published: June 2020

Due to the introduction of novel therapeutic agents, the prognosis of Multiple Myeloma has greatly improved over the last decades. The current standard for fit patients is a bortezomib-based induction therapy, followed by high-dose chemotherapy and autologous stem cell transplantation and lenalidomide-based maintenance therapy. For older, non-transplant-eligible patients, daratumumab in combination with bortezomib or lenalidomide offers a well-tolerated, effective treatment option. Despite large improvements, there is still no cure for most myeloma patients, the aim of therapy is therefore to reach a deep remission to prevent lasting damage followed by a continuous maintenance therapy to uphold the remission and prolong overall survival.
Schnittstelle KFO/MKG-Chirurgie –
interdisziplinäre Therapie
Authors: Kirschneck Christian , Proff Peter , Reichert Torsten E.
Published: June 2020

Viele kieferorthopädisch relevante Anomalien können nicht
allein durch den Kieferorthopäden behandelt werden, sondern
bedürfen der Unterstützung der weiteren Fachdisziplinen der
Zahnheilkunde, allen voran der Mund-, Kiefer- und Gesichtschirurgie. Die
Schnittstellen beider Disziplinen sind dabei vielfältig und breit
gefächert – sie umfassen nicht allein das Spektrum der
Dysgnathie-Operationen im Erwachsenenalter zur Korrektur skelettaler
transversaler, vertikaler und sagittaler Lageanomalien der Kiefer, dem
natürlich der größte Anteil zukommt, sondern auch
oralchirurgische Eingriffe, welche in Zusammenhang mit
kieferorthopädischen Maßnahmen erforderlich werden. Hierzu
zählen die Entfernung überzähliger und aus
Platzgründen zu extrahierender bleibender Zähne, als auch
die chirurgische Freilegung verlagerter und retinierter Zähne. Im
Rahmen von Nichtanlagen stellen oftmals implantat-prothetische Versorgungen
nach entsprechender Pfeilerverteilung und Lückenöffnung eine
gute Versorgungsmöglichkeit zur oralen Rehabilitation der Patienten
dar, was eine enge interdisziplinäre Planung zur optimalen
Vorbereitung der notwendigen Insertion dentaler Implantate erfordert. Im
folgenden Artikel soll ein Überblick über die
vielfältigen Schnittstellen zwischen der Kieferorthopädie
und der Mund-, Kiefer- und Gesichtschirurgie anhand ausgewählter
Patientenfälle gegeben werden sowie die besonderen Erfordernisse in
der interdisziplinären Therapieplanung.
Bundesteilhabegesetz: Chancen für Menschen mit extremer Adipositas
Authors: Siebert Maxi Florentine , Baumann Alwin , Wabitsch Martin
Published: June 2020

Background Children and adolescents with severe obesity suffer from significant disadvantages in many areas of life. Equal participation in life in society is hardly possible for this group of people. In order to counteract this, it was examined whether children and adolescents with severe obesity are considered disabled under the Social Code.

Results In the context of the revised concept of disability, severe obesity in children and adolescents can be considered a disability. Accordingly, a claim to benefits for participation is possible. Such benefits include special rules and aids that could significantly improve the lives of severe obese children and adolescents.

Conclusion The authors agree that children and adolescents with severe obesity, in the most common cases, qualify to claim benefits.
Die Transfusion bei anämischen Neuentbundenen um
1859
Authors: Lehmann Volker
Published: June 2020

Der römische Dichter Ovid erzählt uns von der Zauberin Medea von
Colchos, die den Einfall hatte, die Adern eines alten Menschen zu öffnen,
das Blut laufen zu lassen und durch junges Blut zu ersetzen und damit neues Leben zu
gewinnen.
Klinische Anwendung des digitalen Workflows am Beispiel von
Mini-Implantaten
Authors: Willmann Jan H. , Wilmes Benedict , Chhatwani Sachin , Drescher Dieter
Published: June 2020

Die Nutzung digitaler Technologien erhält zunehmend Einzug in die
Anwendung von Mini-Implantaten und die dazugehörigen
Suprakonstruktionen. Der aktuelle Stand der virtuellen Implantatplatzierung
und die ein- oder 2-zeitigen Workflows werden beleuchtet. Anhand von
Fallbeispielen werden die Workflows, deren klinische Anwendung sowie Vor-
und Nachteile diskutiert.
Surgical Anatomy for Extended Facelift Techniques
Authors: Cakmak Ozcan , Emre Ismet Emrah
Published: June 2020

Preservation of the facial nerve is crucial in any type of facial procedure. This is even more important when performing plastic surgery on the face. An intricate knowledge of the course of the facial nerve is a requisite prior to performing facelifts, regardless of the technique used. The complex relationship of the ligaments and the facial nerve may put the nerve at an increased risk of damage, especially if its anatomy is not fully understood. There are several danger zones during dissection where the nerve is more likely to be injured. These include the areas where the nerve branches become more superficial in the dissection plane, and where they traverse between the retaining ligaments of the face. Addressing these ligaments is crucial, as they prevent the transmission of traction during facelifts. Without sufficient release, a satisfying pull on the soft tissues may be limited. Traditional superficial musculoaponeurotic system techniques such as plication or imbrication do not include surgical release of these attachments. Extended facelift techniques include additional dissection to release the retaining ligaments to obtain a more balanced and healthier look. However, these techniques are often the subject of much debate due to the extended dissection that carries a higher risk of nerve complications. In this article we aim to present the relationship of both the nerve and ligaments with an emphasis on the exact location of these structures, both in regard to one another and to their locations within the facial soft tissues, to perform extended techniques safely.
Why general artificial intelligence will not be realized
Authors: Fjelland Ragnar
Published: June 2020

The modern project of creating human-like artificial intelligence (AI) started after World War II, when it was discovered that electronic computers are not just number-crunching machines, but can also manipulate symbols. It is possible to pursue this goal without assuming that machine intelligence is identical to human intelligence. This is known as weak AI. However, many AI researcher have pursued the aim of developing artificial intelligence that is in principle identical to human intelligence, called strong AI. Weak AI is less ambitious than strong AI, and therefore less controversial. However, there are important controversies related to weak AI as well. This paper focuses on the distinction between artificial general intelligence (AGI) and artificial narrow intelligence (ANI). Although AGI may be classified as weak AI, it is close to strong AI because one chief characteristics of human intelligence is its generality. Although AGI is less ambitious than strong AI, there were critics almost from the very beginning. One of the leading critics was the philosopher Hubert Dreyfus, who argued that computers, who have no body, no childhood and no cultural practice, could not acquire intelligence at all. One of Dreyfus’ main arguments was that human knowledge is partly tacit, and therefore cannot be articulated and incorporated in a computer program. However, today one might argue that new approaches to artificial intelligence research have made his arguments obsolete. Deep learning and Big Data are among the latest approaches, and advocates argue that they will be able to realize AGI. A closer look reveals that although development of artificial intelligence for specific purposes (ANI) has been impressive, we have not come much closer to developing artificial general intelligence (AGI). The article further argues that this is in principle impossible, and it revives Hubert Dreyfus’ argument that computers are not in the world.
Blood writing as extraordinary artifact and agent for socioreligious change
Authors: Yu Jimmy
Published: June 2020

This paper explores blood written texts, particularly Buddhist scriptures, as unique artifacts of sanctity. It also examines the extraordinary uses of blood in premodern times and how people have negotiated socioreligious relationships in their production of blood writings, which were seen as a product of meticulous, controlled ritual practice, an act of asceticism par excellence. We typically think of written text as a means to an end, an expression of ideas and knowledge that privilege the written word as the carrier of message, something to be read and understood. However, Buddhist “blood writing” challenges these received notions of how meaning is communicated; blood writings are far more than carriers of a message. When we view these documents, when we experience their material presence and, at the same time, understand their extraordinary mode of production, we have a unique opportunity to appreciate the socioreligious significance of such texts in the premodern world of East Asia.
Corrigendum to: Incorporating movement patterns to discern habitat selection: black bears as a case study
Authors: Karelus Dana L. , McCown J. Walter , Scheick Brian K. , van de Kerk Madelon , Bolker Benjamin M. , Oli Madan K.
Published: June 2020

Context
Animals' use of space and habitat selection emerges from their movement patterns, which are, in turn, determined by their behavioural or physiological states and extrinsic factors.

Aim
The aims of the present study were to investigate animal movement and incorporate the movement patterns into habitat selection analyses using Global Positioning System (GPS) location data from 16 black bears (Ursus americanus) in a fragmented area of Florida, USA.

Methods
Hidden Markov models (HMMs) were used to discern the movement patterns of the bears. These results were then used in step-selection functions (SSFs) to evaluate habitat selection patterns and the factors influencing these patterns.

Key results
HMMs revealed that black bear movement patterns are best described by three behavioural states: (1) resting (very short step-lengths and large turning angles); (2) encamped (moderate step-lengths and large turning angles); and (3) exploratory (long step-lengths and small turning angles). Bears selected for forested wetlands and marsh wetlands more than any other land cover type, and generally avoided urban areas in all seasons and when in encamped and exploratory behavioural states. Bears also chose to move to locations farther away from major roads.

Conclusions
Because habitat selection is influenced by how animals move within landscapes, it is essential to consider animals' movement patterns when making inferences about habitat selection. The present study achieves this goal by using HMMs to first discern black bear movement patterns and associated parameters, and by using these results in SSFs to investigate habitat selection patterns. Thus, the methodological framework developed in this study effectively incorporates state-specific movement patterns while making inferences regarding habitat selection. The unified methodological approach employed here will contribute to an improved understanding of animal ecology as well as informed management decisions.

Implications
Conservation plans focused on preserving forested wetlands would benefit bears by not only providing habitat for resting and foraging, but also by providing connectivity through fragmented landscapes. Additionally, the framework could be applied to species that follow annual cycles and may provide a tool for investigating how animals are using dispersal corridors.
“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

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

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

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

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

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

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

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

When 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

This 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

The 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

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

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

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

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

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

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

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

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.
Fuzzy Self-Adaptive Sliding Mode Control for Pneumatic Cylinder Rod-Piston Motion Precision Control.
Authors: Iskandar Putra Mohd , Irawan Addie , Mohd Taufika Raja
Published: June 2020

This paper presents the Fuzzy Self-Adaptive Sliding Mode Controller (FSASMC) designed to control a pneumatic cylinder rod-piston motion and precision. The pneumatic system is widely used in the industry due to its advantages such as high weight to power ratio, high traveling speed, clean fluid medium, and cost-effective in terms of price and maintenance. However, due to the high nonlinearity behavior of pneumatic system, the position control of the pneumatic system is still a challenging task. The most critical part of controlling the pneumatic system with various motion is in giving a stable pressure in chambers, while the rod-piston motion is precisely controlled with any shape of inputs with minimum friction. Therefore, FSASMC is proposed to cater to this matter with fast responses through Sliding Mode Control (SMC) and dynamic stability in pressures through Fuzzy Self-adaptive tuning using Fuzzy Logic Control (FLC). The proposed control system is verified, and analysis was emphasized on steady-state error, velocity, pressure in pneumatic cylinder chambers, and frictional force. Simulation results show that the proposed controller approach performing fast-tracking error on pneumatic rod-piston motion with a very low steady-state error, no oscillation and stable in air pressures.
Automated Asian Fruit Grading System Using Stereo Vision Technique
Authors: Abd Rashid Anith Nuraini , Amir Faizal , Ramlan Siti Azura , Harron Nur Athiqah , Mohd Saod Aini Hafizah
Published: June 2020

In Malaysia, most of fruit planters are still using the conventional methods of inspection and grading their products by manual weightage measurement and visual inspection. Conventional methods rely on human eyes to perform the grading which leads to unproductive system and lack of data management. Therefore, in this study, an automated weight grading system is proposed to perform the grading system via size measurement using stereo vision system and image processing. The fruit selected to verify the system proposed performance were fruit samples provided by MARDI Bukit Tangga located in Kedah, Malaysia. In the vision system, triangulation method is used where the samples were graded more accurately using two cameras to form a stereo vision system. The image capture through the vision system processed using multiple image processing steps such as image segmentation, sobel edge sensor and multiple morphological operation. The relationship between weight and area of fruits done via regression methods with adjusted R-square of 0.9823. Using this goodness of fit, weight estimation can be executed with Root Mean Squared Error (RMSE) of 6.811. Overall, fruit grading system with the stereo vision of a low-cost web camera implementation has successfully performed with the accuracy of 85.65% and a Mean Absolute Percentage Error (MAPE) of 6.551%.
Band Gap Narrowıng of Mg1-xCuxO Nanostructured Materials
Authors: Badar Nurhanna , Kamarulzaman Norlıda , Chayed Nor Fadılah , Elong Kelımah , Yahaya Subban Ri Hanum
Published: June 2020

The band gap energies of MgO nanostructured can be tuned to a suitable value needed for various applications by substitution with dopant element. The study on doped compounds is to investigate band gap changes in the new materials. In this work, MgO and its doped materials Mg1-xCuxO (x = 0.02, 0.04, 0.06) were synthesized using a combustion method. The phase and purity of materials were studied using X-Ray diffraction (XRD). The morphology and crystallites size of the materials were examined by a Field Emission Scanning Electron Microscope (FESEM). It was found that the synthesis route using triethanolamine for the combustion synthesis is suitable in obtaining pure and single phase MgO and Mg1-xCuxO nanostructured. The presence of doped element, Cu in the MgO had caused changes in morphologies and crystallite size of the materials. The band gap energy of the materials was measured using a UV-Vis NIR spectrophotometer. The absorption edges of Mg1-xCuxO were observed to shift to the right with respect to those of MgO as the Cu content increases, implying that band gap narrowing occurred in the materials.
Microstructure Study of Calcium Manganese Oxide (CaMnO3) as Perovskite Materials
Authors: Nurhaziqah A M S , Afiqah I Q , Hisam Abd. Aziz Mohd Fazrul , Aziz N A Nik , Zalani Daud Muhamad , Hasiah S , Nurhayati I
Published: June 2020

The use of metal oxide as an n-type semiconductor behavior is one of the important material in solar cells. Among the materials, these researches focus on perovskite structure of CaMnO3. The single phase of CaMnO3 synthesised by citrate method were studied for the microstructure of CaMnO3. The perovskite structure of CaMnO3 was characterized by using X-ray Diffraction (XRD), Fourier transform-infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM) and Thermogravimetric Analysis (TGA). Results indicated that the single phase of CaMnO3 was revealed by XRD analysis. The specific interactions in the metal oxide and hence about the complexation led by FTIR. The morphological structure of the samples was studied by SEM, which confirmed the XRD analysis. While TGA analysis affirmed the CaMnO3 was formed.
Rapid Reduction of Graphene Oxide Thin Films on Large-Area Silicon Substrate
Authors: Masrie M , Badaruddin SAM , Hussin MRM , Nor NMRM , Joe J
Published: June 2020

Graphene oxide thin films were fabricated on 8-inch silicon/silicon dioxide (Si/SiO2) wafers for nanoelectronic applications. The fabrication was performed using an ultrasonic spray coating method and reduced by rapid thermal processing (RTP). The micrometer-sized droplets from an ultrasonic spray of stable dispersion Graphene Oxide (GO) in ethanol form uniforms films on large-area silicon substrates. Optical microscope images clearly showed uniform thin films resulting from the overlapped of GO dispersion droplets. The chemical and structural parameter characterization were performed by field emission scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). The spray coating process using an ultrasonic atomizer system with optimum parameters and the thermal reduction process using RTP at 1100 °C produces low sheet resistance values ranging from 1 to 4 kOhms/sq with non-uniformity less than 20%.
High-k LaxCeyOz for Passivation of Si Substrate
Authors: Quah Hock Jin , Cheong Kuan Yew , Lockman Zainovia , Hassan Zainuriah , Lim Way Foong
Published: June 2020

High dielectric constant rare earth lanthanum cerium oxide (LaxCeyOz) films have been studied as the passivation layers for silicon substrate. Effects of post-deposition annealing time (15, 30, and 45 min) at 700°C towards capacitance-voltage characteristics of the films were investigated. As the annealing time was increased from 15 to 45 min, negative flatband voltage shift was observed, signifying the presence of positive charges in the samples. Interface trap density value calculated for the samples has shown to be the lowest for the film annealed for 45 min, owing to the presence of silicate interfacial layer to improve the overall interfacial quality.