Matrices as arrows! A biproduct approach to typed linear algebra

Motivated by the need to formalize generation of fast running code for linear algebra applications, we show how an index-free, calculational approach to matrix algebra can be developed by regarding matrices as morphisms of a category with biproducts. This shifts the traditional view of matrices as indexed structures to a type-level perspective analogous to that of the pointfree algebra of programming. The derivation of fusion, cancellation and abide laws from the biproduct equations makes it easy to calculate algorithms implementing matrix multiplication, the kernel operation of matrix algebra, ranging from its divide-and-conquer version to the conventional, iterative one. From errant attempts to learn how particular products and coproducts emerge from biproducts, we not only rediscovered block-wise matrix com- binators but also found a way of addressing other operations calculation- ally such as e.g. Gaussian elimination. A strategy for addressing vector- ization along the same lines is also given.FCT, Mondrian Project funded by contract PTDC/EIA-CCO/108302/2008

Analysis of the Earthquake-Resistant Design Approach for Buildings in Mexico

The development of new codes for earthquake-resistant structures has made possible to guarantee a better performance of buildings, when they are subjected to seismic actions. Therefore, it is convenient that current codes for design of building become conceptually transparent when defining the strength modification factors and assessing maximum lateral displacements, so that the design process can be clearly understood by structural engineers. The aim of this study is to analyze the transparency of earthquake-resistant design approach for buildings in Mexico by means of a critical review of the factors for strength modification and displacement amplification. The approach of building design codes in US is also analyzed. It is concluded that earthquake-resistant design in Mexico have evolved in refinement and complexity. It is also demonstrated that the procedure prescribed by such design codes allows the assessment of the design strengths and displacements in a more rational way, in accordance not only with the present stage of knowledge but also with the contemporary tendencies in building codes. In contrast, the procedures used in US codes may not provide a clear view for seismic response assessment of buildings

Percursos a integrar numa rede de corredores verdes para a Ria de Aveiro: um exercício de planeamento

Pretende-se com este artigo apresentar um contributo para a definição de uma rede de corredores verdes para a zona costeira e lagunar da Ria de Aveiro, como resultado de um exercício de planeamento e ordenamento realizado ao longo dos últimos dois anos e para o qual contribuiram diversos trabalhos realizados pela equipa de Planeamento e Gestão da Zona Costeira, do Departamento de Ambiente e Ordenamento da Universidade de Aveiro. Os vários cais de acostagem existentes ao longo das margens da Ria, potenciam o usufruto deste recurso enquanto espaço previlegiado de lazer e recreio, sendo também por essa razão uma área particularmente interessante para investigar novas metodologias de intervenção ao nível da gestão integrada das zonas costeiras e lagunares e também das estruturas ecológias e fluviais, elementos base na fundamentação de criação de uma Rede de Corredores Verdes de nível regional, sejam eles pedonais, cicláveis ou mesmo fluviais

Análisis de la gestión de seguridad de los protocolos WPA y WPA2 en el tráfico de datos de una red LAN con tecnología WiFi

Este documento pretende explicar paso a paso el sistema utilizado por los protocolos de seguridad de acceso e intercambio de datos WPA Y WPA2 utilizados por el sistema de comunicaciones WiFi. En primera instancia, debemos comprender el funcionamiento y régimen que lleva consigo una red LAN, tratando de enfocarnos en lo que es la tecnología WiFi. Hablaremos de los estándares que rigen la tecnología WiFi y su evolución lo cual nos permite tener una introducción al tema principal y que veremos reflejado en lo que llamamos el Capítulo 1. En el capítulo 2, llevamos a cabo la explicación del funcionamiento y gestión que realizan los protocolos WPA y WPA2, los cuales utilizan sistemas conocidos e implementados desde hace muchos años y aplicados a lenguaje de computadora como es la encriptación y la autenticación que serán las principales herramientas en la defensa de una red WiFi. El paso a seguir ahora, será, el de identificar los ataques que podemos tener en nuestra red casera o empresarial, puesto que desde la implementación de las redes inalámbricas se han generado una serie de ataques con enfoque malicioso,por lo que es indispensable el uso de sistemas de protección. También mostraremos la gestión y los pasos que debemos seguir para minimizar estos riesgos

Data acquisition and meter unit based in wifi communication protocol

Without doubt, the competitive fast rhythm of the industries is one of the main causes helped bring to the accelerated growth of the electronic technology and the communication. The need to develop new products with a best quality, cheaper and faster as assure and increase the quality of the products in the international markets, requires of new technologies to the metering, monitoring and control of their production processes, of which finality is to improve the processes to guaranteed their products in the market in the less time possible, the best quality and low cost for the final consumer. This work is based in the design and implementation of a Wireless Data Acquisition Unit based in WiFi protocol, which is oriented to meter, monitoring and the control of processes in the industry, commercial and the home automation applications, using one of the wirelessprotocols with the biggest acceptance in the market, with the main objective of to take advantage of the installed physical infrastructure in the place of the application, like industry, company or house. The Unit is based in the RN-131G, a Roving Network company module, which is able to work in stand-alone mode with ultralow power consummation and supporting the IEEE 802.11b/g protocols, in which is possible to achieve transfer rates of up to 11 Mbps and 54 Mbps in /b & /g specifications respectively. Whit this unit is possible to meter up to 5 analogs signals with 14 bits precision and has include a temperature and relative humidity sensors. This unit can meter two digital signals and act mean two digitals outputs, and gas include an USB port for communication and programming tasks

Estudo de viabilidade e proposta de topologia de um sistema de gerenciamento de energia para nanosatélites da constelação Alfa Crux

Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Engenharia Elétrica, 2020.O presente trabalho apresenta um estudo de viabilidade e ao final propõe uma versão para o desenvolvimento de um dispositivo EPS, sigla para Electrical Power System, para um Cubesat 1U. O objetivo consiste em propor uma placa eletrônica que realize a aquisição, armazenamento e distribuição de energia, além de atender os demais requisitos da missão em diversas frentes, tais como a padronização, as conexões com os sistemas embarcados necessários, os requisitos de operação, o consumo, entre outros. Será apresentado em detalhes um background com missões anteriores, de outras universidades do mundo inteiro, alguns conceitos teóricos necessários e, por fim, o hardware proposto para o projeto. Esse trabalho está inserido no contexto do projeto Alfa Crux, desenvolvido pelo laboratório LODESTAR, Laboratório de Simulação e Controle de Sistemas Aeroespaciais, da Universidade de Brasília (UnB), que tem como um de seus objetivos desenvolver uma constelação de nanossatélites, sendo o primeiro lançamento previsto para até o final de 2021, início de 2022

Study of a magnetorheological fluid submitted to a uniform magnetic field

ABSTRACT: In this work, the rheological and hyperfine properties of a magnetorheological fluid (MRF) under the action of a uniform external magnetic field are analysed. Powders of native mineral magnetite of micrometric particle size, after a pulverization process, form the solute of these fluids. The sizes of these samples are selected by sieving in order to obtain sizes of around 20μm and 45μm. The powders are characterized by means of Mössbauer spectroscopy to analyse their stoichiometry giving rise to a non-stoichiometric magnetite Fe2.96O4 in addition to a hematite component. Result of viscosity and shear stress in the low-speed regime were analysed using the Hershel Buckley method. In particular, the case of surface tension it decreases with the application of a uniform magnetic flux density, which is understood in terms of a phase separation due to the formation of mesoscopic structures, thus decreasing the cohesion force and increasing the adhesion force

A Facebook event collector framework for profile monitoring purposes

Social networks have recently emerged to become vital tools for information and content dissemination among connections. Indeed, the immense increase of number of users of Facebook made it rise to become the largest existing social network with more than 1.2 billion active users. However, these numbers also rose the attention of hackers and attackers who aim at propagating malware and viruses for obtaining confidential information regarding social network users. In this manner, it is crucial that each Facebook user is able to easily access, control and analyse the information shared on the corresponding profile so that profile usage deviations can be more efficiently detected. However, despite the fact that Facebook allows an analysis of all user actions through the Timeline Review, this information is not comprehensively organized and there is no statistical analysis of the user generated data. In this paper, we propose a novel framework comprising a Facebook event collector, which by being provided with an authentication token for a user profile obtained through a Facebook application developed for this purpose, collects all the corresponding posted information and stores it in a relational database for \textit{a posteriori} analysis. Through the graphical interface of the developed application, users can access all stored information in a comprehensible manner, according to the type of event, thus facilitating the analysis of user behaviour. By storing each event with the corresponding timestamp, we are able to perform an efficient and comprehensive analysis of all posted contents and compute statistical models over the obtained data. In this manner, we can create a notion of normal usage profile and detect possible deviations which may be indicative of a compromised user account