A commentary on Freudenthal’s didactic phenomenology of the mathematical structures associated with the notion of measurement

This paper discusses Freudenthal\u27s didactical phenomenology for the mathematical structures related to measurement. Freudenthal starts with the set G of all objects having the attribute of weight, an attribute that is to be measured. He proposes two operations, the first one among the measurements themselves, called “addition . Addition is interpreted in terms of the mental actions associated with measurement and, in the case of weights, it consists on the process of placing weights on one of the two dishes of a balance in order to balance them with a predetermined gauge, its fractions or multiples thereof, which are placed on the other. Their total weight is obtained by comparison with a predetermined gauge. The second operation, between weights and positive integers, allow weights to be amplified (by adding as many times as desired their weight measure). A related operation to amplification is that of contraction (by dividing the weight into as many equal parts as desired.) Freudenthal then extends his definitions in order to assign a meaning to the multiplication of a measure by, first, any positive rational number, and, second, by completeness, to any real number. Freudenthal\u27s didactical phenomenology is based on the historical phenomenology of measurement, fractions, decimals and percentages. It is a central tenet of Realistic Mathematics Education (RME) that didactical phenomenologies of mathematical structures constitute proposals from which to make cognitively advantageous teaching sequences for the relevant mathematical structures. We discuss how Freudenthal\u27s phenomenology of the mathematical structures for measurement gets translated into the mathematical models associated with the rational numbers. Finally, we make reference to a paradigmatic teaching unit which incorporates coherently Freudenthal\u27s didactical phenomenology

A semiotic reflection on the didactics of the Chain rule

According to (Fried, 2008), there is an intrinsic tension in trying to apply the history of mathematics to its didactics. Besides the widespread feeling that the introduction of didactic elements taken from the history of mathematics can detract the pedagogy of mathematics from the attainment of important goals, (Fried, 2008, p. 193) describes a pair of specific pitfalls that can arise in implementing such historical applications in mathematics education. The description in (Fried, 2008), is presented in the parlance of Sausserian Semiotics and identifies two semiotic “deformations” that arise when one fails to observe that the pairing between signs and meanings in a given synchronic “cross-section” associated with the development of mathematics need not hold for another synchronic cross section at a different time. In this exposition, an example related to an application of the history of the chain rule to the didactics of calculus is presented. Our example illustrates the semiotic deformations alluded by (Fried, 2008), and points out a possible explanation of how this may lead to unrealistic pedagogical expectations for student performance. Finally, an argument is presented for the creation of a framework for a historical heuristics for mathematics education, possibly beyond the bounds of semiotics

Security Architecture for Swarms of Autonomous Vehicles in Smart Farming

Nowadays, autonomous vehicles are incorporated into farms to facilitate manual labour. Being connected vehicles, as IoT systems, they are susceptible to cyber security attacks that try to cause damage to hardware, software or even living beings. Therefore, it is important to provide sufficient security mechanisms to protect both the communications and the data, mitigating any possible risk or harm to farmers, livestock or crops. Technology providers are aware of the importance of ensuring security, and more and more secure solutions can be found on the market today. However, generally, these particular solutions are not sufficient when they are part of complex hybrid systems, since there is no single global solution proposal. In addition, as the number of technologies and protocols used increases, the number of security threats also increases. This article presents a cyber-security architecture proposal for swarms of heterogeneous vehicles in smart farming, which covers all of the aspects recommended by the ISO 7798-2 specification in terms of security. As a result of this analysis, a detailed summary of the possible solutions and available technologies for each of the communication channels of the target system as well as some recommendations are presented.ECSEL JU (H2020–EU.2.1.1.7.–ECSEL RIA) and the Spanish Ministry of Economic Affairs and Digital Transformatio

Determinar las condiciones establecidas en el ordenamiento jurídico colombiano para la legalización de los asentamientos humanos urbanos

Este artículo tiene como objetivo, determinar las condiciones establecidas en el ordenamiento jurídico colombiano para la legalización de los asentamientos humanos urbanos. Por lo tanto, para su desarrollo, se efectuó una investigación de tipo cualitativo, documental y exploratoria. Lo cual permitió establecer que los asentamientos humanos son una problemática que se ha venido viviendo en el país como consecuencia del desplazamiento forzado, despojo de tierras, migraciones campesinas, entre otros, que ha generado la ubicación en asentamientos urbanos, definidos, como un conjunto de personas que se posesionan o invaden un predio privado o público para desarrollar sus viviendas, teniendo como característica condiciones marginales y de precariedad. El marco normativo colombiano en materia de derecho urbanístico fue desarrollándose y mejorando a través de los años, medidas que la han dado en cierta medida un orden a la construcción desordenada que se efectuó inicialmente, por la ausencia de un plan de desarrollo territorial. Los avances en materia urbanística, permitió en cierta medida la legalización de los asentamientos urbanos, para que sus predios pudieran gozar de reconocimiento jurídico. También dentro de los aportes del marco normativo, fue establecer las obligaciones del estado en brindar las condiciones para que las personas en estado de indefensión y vulnerabilidad pudieran acceder a viviendas de interés social y con ello mitigar la ocupación de asentamientos ilegales.The objective of this article is to determine the conditions established in the colombian legal system for the legalization of urban human settlements. Therefore, for its development, a qualitative, documentary and exploratory research was carried out. this made it possible to establish that human settlements are a problem that has been experienced in the country as a consequence of the forced displacement, dispossession of land, peasant migration, among others, it has generated the location in urban settlements, defined as a set of people who own or invade a private or public property to develop their homes, having as characteristic marginal and precarious conditions. The colombian regulatory framework in the area of urban planning law was developed and improved over the years, measures that have given a certain order to the disorderly construction that was carried out initially, for the absence of a territorial development plan. Advances in urban planning allowed to some extent the legalization of urban settlements, so that their lands could enjoy legal recognition. Also within the inputs of the normative framework, was to establish the obligations of the state to provide the conditions for persons in a state of defencelessness and vulnerability to access social housing and thereby to mitigate the occupation of illegal settlements

Criterios de implementación ISO 14000:2015 Caso Estudio Hidroeléctrica Ituango.

Criterios de implementación ISO 14000:2015 Caso Estudio Hidroeléctrica Ituango.En la medida en que crece la preocupación por mantener y mejorar la calidad del medio ambiente y proteger la salud humana, organizaciones de todo tipo están enfocando cada vez más su atención hacia los impactos potenciales de las actividades que realizan para la generación de productos y/o prestación de servicios. El desempeño ambiental de una organización es de gran importancia para los clientes internos, externos y las partes interesadas. El logro de un desempeño ambiental razonable requiere de un compromiso de la organización, para un enfoque sistémico y un mejoramiento continuo de su Sistema de Gestión Ambiental (SGA). Partiendo de la evaluación de los impactos ambientales generados sobre el medio ambiente por la construcción y operación del proyecto hidroeléctrico ituango, se presenta el ajuste del Plan de Manejo Ambiental, que es la herramienta para la implementación de medidas especícas desde la fase de planteamiento del Proyecto. El objetivo principal del Plan de Manejo Ambiental es formular los mecanismos que permitan aplicar oportunamente una medida, bien sea de manejo, prevención, mitigación, control, protección, vigilancia o compensación, en las áreas de interés humano y ecológico para la zona de infuencia del proyecto. En este documento se abordara uno de los impactos ambientales ocasionados por la construcción de la mega obra de la Hidroeléctrica de ituango el cual es la contaminación atmosférica.To the extent that the concern for maintaining and improve the quality of the environment and protect health human, organizations of all types are focusing on each more and more attention to the potential impacts of activities that they carry out for the generation of products and / or provision of services. The environmental performance of a organization is of great importance to customers internal, external and interested parties. The achievement of a Reasonable environmental performance requires a commitment of the organization, for a systemic approach and a continuous improvement of its Environmental Management System (SGA). Based on the evaluation of environmental impacts generated on the environment by the construction and operation of the ituango hydroelectric project, the adjustment of the Environmental Management Plan, which is the tool for the implementation of specific measures from the phase of the Project. The main objective of the Plan of Environmental Management is to formulate the mechanisms that allow a measure to be applied in a timely manner, whether management, prevention, mitigation, control, protection, surveillance or compensation, in areas of human and ecological interest for the area of ​​in uence of the project. This document will address one of the impacts environmental impacts caused by the construction of the mega of the Ituango Hydroelectric which is the pollution atmospheri

Multi-Criteria Selection of Additives in Porous Asphalt Mixtures Using Mechanical, Hydraulic, Economic, and Environmental Indicators

Porous asphalt (PA) mixtures are more environmentally friendly but have lower durability than dense-graded mixtures. Additives can be incorporated into PA mixtures to enhance their mechanical strength; however, they may compromise the hydraulic characteristics, increase the total cost of pavement, and negatively affect the environment. In this paper, PA mixtures were produced with 5 different types of additives including 4 fibers and 1 filler. Their performances were compared with the reference mixtures containing virgin bitumen and polymer-modified bitumen. The performance of all mixes was assessed using: mechanical, hydraulic, economic, and environmental indicators. Then, the Delphi method was applied to compute the relative weights for the parameters in multi-criteria decision-making methods. Evaluation based on distance from average solution (EDAS), technique for order of the preference by similarity to ideal solution (TOPSIS), and weighted aggregated sum product assessment (WASPAS) were employed to rank the additives. According to the results obtained, aramid pulp displayed comparable and, for some parameters such as abrasion resistance, even better performance than polymer-modified bitumen, whereas cellulose fiber demonstrated the best performance regarding sustainability, due to economic and environmental benefits.This work and the APC are funded by SAFERUP! Project, from the European Union’s Horizon 2020 research and innovation program under, the Marie Skłodowska-Curie grant agreement No. 765057

Bacteremic Pneumococcal Pneumonia: a Longitudinal Study in 279 Adult Patients from a Single Center

Background: Bacteremic pneumococcal pneumonia (BPP) is the most common clinical presentation of invasive pneumococcal disease (IPD). Although it has been extensively studied, there is little knowledge in our region in relation to burden of disease, demographic and outcome features. Methods: We conducted a prospective, longitudinal, observational study from 1989 to 2015 in adult patients with BPP, in order to deepen our knowledge of the characteristics of this disease in our community hospital in Tandil, Argentina. Results: 279 patients were included. The mean incidence was 2.8/1000 admissions with a sharp decrease in the last two years, reaching 0.8/1000 admissions. Mean patient age was 60 years. Comorbidities were found in 65% of the cases. Non-respiratory symptoms occurred in 50% of cases. Infiltrates on chest x ray were predominantly unilateral (75%) and lobar (57%). Regarding severity, a low PSI score I-II-II was found in 178 patients (64%), 60 (22%) were admitted to ICU, 40 (14%) required mechanical ventilation, and 21 (8%) developed empyema. Penicillin resistance was not found. Mortality was 18% (49/279), and by a multivariate analysis it was associated with confusion (OR= 5.44), age\u3e80 years (OR =5.72), leukopenia (OR =5.73) and dyspnea (OR=7.87). Conclusions: In this study of 279 bacteremic pneumococcal pneumonia we reinforce previous knowledge on this disease regarding incidence and clinical features and confirm a considerable an early mortality associated to age and severity of disease at onset. Recent changes in incidence of BPP in adults could be secondary to herd effect of PVC 13 a vaccine that is mandatory in children in our community since 2012

Bacteremic Pneumococcal Pneumonia: a Longitudinal Study in 279 Adult Patients from a Single Center

Background: Bacteremic pneumococcal pneumonia (BPP) is the most common clinical presentation of invasive pneumococcal disease (IPD). Although it has been extensively studied, there is little knowledge in our region in relation to burden of disease, demographic and outcome features.Methods: We conducted a prospective, longitudinal, observational study from 1989 to 2015 in adult patients with BPP, in order to deepen our knowledge of the characteristics of this disease in our community hospital in Tandil, Argentina.Results: 279 patients were included. The mean incidence was 2.8/1000 admissions with a sharp decrease in the last two years, reaching 0.8/1000 admissions. Mean patient age was 60 years. Comorbidities were found in 65% of the cases. Non-respiratory symptoms occurred in 50% of cases.Infiltrates on chest x ray were predominantly unilateral (75%) and lobar (57%). Regarding severity, a low PSI score I-II-II was found in 178 patients (64%), 60 (22%) were admitted to ICU, 40 (14%) required mechanical ventilation, and 21 (8%) developed empyema. Penicillin resistance was not found. Mortality was 18% (49/279), and by a multivariate analysis it was associated with confusion(OR= 5.44), age>80 years (OR =5.72), leukopenia (OR =5.73) and dyspnea (OR=7.87).Conclusions: In this study of 279 bacteremic pneumococcal pneumonia we reinforce previous knowledge on this disease regarding incidence and clinical features and confirm a considerable an early mortality associated to age and severity of disease at onset. Recent changes in incidence of BPP in adults could be secondary to herd effect of PVC 13 a vaccine that is mandatory in children in our community since 2012.Fil: Gentile, Jorge. Hospital Ramon Santamarina de Tandil; ArgentinaFil: Hernandez, Claudia. Hospital Ramon Santamarina de Tandil; ArgentinaFil: Sparo, Mónica Delfina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Rodriguez, Edgardo Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Ceriani, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Bruggesser, Alicia Florencia. Hospital Ramon Santamarina de Tandil; Argentin

Proposal of a New Porous Concrete Dosage Methodology for Pavements

Although porous concrete pavement design methods are mainly focused on maintaining high permeability rates in order to improve their ability to manage stormwater runoff, the mixture strength is paramount for its durability and service life. This paper proposes a new mixture design method for porous concrete, named PCD (porous concrete design), derived from the ACI 522R-10 and ACI 211.3R-02 standards. The aim is to improve mechanical strength in porous concrete mixtures, while ensuring enough permeability for its use in urban roads. With PCD methodology it is possible to obtain mechanical strengths 30% higher than those produced with ACI methodologies, while maintaining permeability rates close to 2 cm/s, lower than those obtained with ACI methods but still enough to manage extreme storm events. Finally, with the analytical Hierarchy Process (AHP) multi-criteria decision-making methodology and also bearing in mind safety variables, the best porous concrete mixtures are the ones produced with PCD methodology.This research was funded by the Spanish Ministry of Economy and Competitiveness and the European Union (ERDF) through the project SUPRIS.SUReS (Ref. BIA2015-65240-C2-1-R)

Mathematical modeling of vertical movement of the upper shaft in cane mills

This study introduces a mathematical model to describe the floating effects of the top roll in sugarcane mills. The model is developed from experimental data measured during the operation of a sugarcane mill. The measured data is fitted using the top shaft rotation period of the mill and dividing on intervals to individually fit each interval obtaining a function defined by parts. The resulting model shows a correlation coefficient of R2 ≥ 0.97. This allow including the floating effect in the study and design of other elements of sugarcane mills