# Articles — Popular

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Sommarmatte
Just some summer math courses.
Alexander Nielsen
Birthcard
A birthcard made for expats. This includes a poem in two languages (Dutch and Spanish) and a nice drawing made by artist Neco Beth
R. Tj. Beth
Using Timing Attacks Against Cryptographic Algorithms
Computer algorithms that are written with the intent to keep data private are used in every day cryptography. These algorithms may exhibit execution time behaviour which is dependant on secret information that is not known to an outsider. When carefully analysed, this dependency may leak information that can be used to gain unintended access to private data, effectively nullifying the use of such algorithms. This threat poses a vital risk to the field of computer cryptography, and analysis should be done in attempt to eradicate this potential threat from any algorithms in modern day use. In this paper, attacks are orchestrated against several algorithms that have previously been used in cryptography, resulting in the successful retrieval of secret data within a manageable time-scale.
Harry Budd
En el siguiente ensayo, usted podrá encontrar encuestas que le brindaran información disponible en la pagina web del DANE, que le mostraran los diferentes estratos socioeconómicos en la ciudad de Medellín. El propósito de este ensayo es mostrar una relación entre los ingresos de los individuos y su felicidad. Dado a que la mayoría de la población de Medellín consta con bajos recursos y sufren necesidades por la falta de ciertas modalidades indispensables para sobrevivir, ellos son felices y están plenos con su estilo de vida.
Maicol Rojas
TRATAMIENTO DE AGUAS NEGRAS Y RESIDUALES Y SU IMPORTANCIA
tratamientos de aguas tanto negras como residuales y su importancia
Santiago Rivera
Entropy Minimization Based Synchronization Algorithm for Underwater Acoustic Receivers
This paper presents a new entropy minimization criterion and corresponding algorithms that are used for both symbol timing and carrier frequency recovery for underwater acoustic receivers. It relies on the entropy estimation of the eye diagram and the constellation diagram of the received signal. During the parameter search, when perfect synchronization is achieved, the entropy will reach a global minimum, indicating the least intersymbol interference or a restored constellation diagram. Unlike other synchronization methods, this unified criterion can be used to build an all-in-one synchronizer with high accuracy. The feasibility of this method is proven using a theoretical analysis and supported by sea trial measurement data.
Xiao Liu
Indoor Air Quality Assessment of Campus Spaces with Carbon Dioxide as a Measure of Adverse Health Effects
Indoor air quality (IAQ) is referred to as “the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants” (US EPA, 2015). Indoor pollutant levels further determine the quality of indoor air, and one of the indicators used to measure IAQ is carbon dioxide (CO2). Drawing on data collected from a classroom, auditorium, and gym setting in the Mount Royal University campus, the aim of this report is to determine if CO2 levels present are within established margins substantial to result in adverse health effects. Environmental factors that are considered in this report include: room size, supply air, and occupant load in the specified spaces on the campus. The results of this study suggest that there are a myriad of factors that may affect IAQ and that CO2 is merely an indicator of poor air quality. Overall, peak indoor CO2 levels can further be used to determine appropriate ventilation rates in an indoor space.
Graham Brown, Isabella Luu
The differential wave equation can be used to describe electromagnetic waves in a vacuum. In the one dimensional case, this takes the form $\frac{\partial^2\phi}{\partial x^2}-\frac{1}{c^2}\frac{\partial^2\phi}{\partial t^2} = 0$. A general function $f(x,t) = x \pm ct$ will propagate with speed c. To represent the properties of electromagnetic waves, however, the function $\phi(x,t) = \phi _0 sin(kx-\omega t)$ must be used. This gives the Electric and Magnetic field equations to be $E (z,t) = \hat{x} E _0 sin(kz-\omega t)$ and $B (z,t) = \hat{y} B _0 sin(kz-\omega t)$. Using this solution as well as Maxwell's equations the relation $\frac{E_0}{B_0} = c$ can be derived. In addition, the average rate of energy transfer can be found to be $\bar{S} = \frac{E_0 ^2}{2 c \mu _0} \hat{z}$ using the poynting vector of the fields.