## Voronoi diagram from smooshing paint between glass

Posted by Armando Brito Mendes | Filed under Investigação Operacional, matemática, SIG's, videos

Uma abordagem original aos diagramas de Voronoi.

Tags: belo, otimização

## How To Forecast Time Series Data With Multiple Seasonal Periods

Posted by Armando Brito Mendes | Filed under estatística, matemática, materiais para profissionais

Análise de séries complexas com múltiplos períodos sazonais

Time series data is produced in domains such as IT operations, manufacturing, and telecommunications. Examples of time series data include the number of client logins to a website on a daily basis, cell phone traffic collected per minute, and temperature variation in a region by the hour. Forecasting a time series signal ahead of time helps us make decisions such as planning capacity and estimating demand. Previous time series analysis blog posts focused on processing time series data that resides on Greenplum database using SQL functions. In this post, I will examine the modeling steps involved in forecasting a time series sequence with multiple seasonal periods. The various steps involved are outlined below:

- Multiple seasonality is modelled with the help of fourier series with different periods
- External regressors in the form of fourier terms are added to an ARIMA model to account for the seasonal behavior
- Akaike Information Criteria (AIC) is used to find the best fit model

Tags: previsão

## A Simple Introduction to Complex Stochastic Processes

Posted by Armando Brito Mendes | Filed under estatística, matemática

Stochastic processes have many applications, including in finance and physics. It is an interesting model to represent many phenomena. Unfortunately the theory behind it is very difficult, making it accessible to a few ‘elite’ data scientists, and not popular in business contexts.

**1. Construction of Time-Continuous Stochastic Processes: Brownian Motion**

**2. General Properties**

Tags: análise de sistemas

## Data Analysis Method: Mathematics Optimization to Build Decision Making

Posted by Armando Brito Mendes | Filed under data mining, Investigação Operacional, matemática, SAD - DSS

Uma pequena introdução à utilização de otimização na análise de dados

Optimization is a problem associated with the best decision that is effective and efficient decisions whether it is worth maximum or minimum by way of determining a satisfactory solution.

Optimization is not a new science. It has grown even since Newton in the 17th century discovered how to count roots. Currently the science of optimization is still evolving in terms of techniques and applications. Many cases or problems in everyday life that involve optimization to solve them. Lately much developed especially in the emergence of new techniques to solve the problem of optimization. To mention some, among others, conic programming, semi definite programming, semi infinite programming and some meta heuristic techniques.

Tags: análise de dados, otimização

## Earliest Known Uses of Words of Mathematics

Posted by Armando Brito Mendes | Filed under estatística, matemática, materiais ensino

**um curioso site onde se registam os significados mais antigos para termos matemáticos**

These pages attempt to show the first uses of various words used in mathematics. Research for these pages is ongoing, and a citation should not be assumed to be the earliest use unless it is indicated as such.

Mathematical Words: Origins and Sources by John Aldrich is an excellent article and companion to this web site.

Please see also Earliest Uses of Various Mathematical Symbols, Images of Mathematicians on Postage Stamps, and Ambiguously Defined Mathematical Terms at the High School Level.

These pages are maintained by Jeff Miller, a teacher at Gulf High School in New Port Richey, Florida. The principal contributors are John Aldrich, Julio González Cabillón, Carlos César de Araújo, and James A. Landau. Other contributors are Manoel de Campos Almeida, Antranig Basman, Dave Cohen, John Conway, Martin Davis, Karen Dee Michalowicz, Joanne M. Despres of Merriam-Webster Inc., Bill Dubuque, Mark Dunn, John G. Fauvel, Walter Felscher, Giovanni Ferraro, Tom Foregger, Michael N. Fried, John Harper, Antreas P. Hatzipolakis, Barnabas Hughes, Samuel S. Kutler, Franz Lemmermeyer, Avinoam Mann, Peter M. Neumann, Ken Pledger, Paul Pollack, Jim Propp, Aldo I. Ramirez, Lee Rudolph, Randy K. Schwartz, Max Urchs, Tom Walsh, William C. Waterhouse, and David Wilkins.

“Perhaps I may without immodesty lay claim to the appellation of *Mathematical Adam,* as I believe that I have given more names (passed into general circulation) of the creatures of mathematical reason than all the other mathematicians of the age combined.” —James Joseph Sylvester, *Nature* 37 (1888), p. 152.

Tags: definição

## R news and tutorials R bloggers

Posted by Armando Brito Mendes | Filed under estatística, matemática, software

Montes de blogs sobre R.

Here you will find daily **news and tutorials about R**, contributed by over 573 bloggers.

## Top 3 Posts from the past 2 days

## Top 9 articles of the week

- Installing R packages
- In-depth introduction to machine learning in 15 hours of expert videos
- New Version of RStudio (v0.99) Available Now
- Using apply, sapply, lapply in R
- Review of ‘Advanced R’ by Hadley Wickham
- Scatterplots
- An R Enthusiast Goes Pythonic!
- Open data sets you can use with R
- Basics of Histograms

Tags: R-software

## Rtips. Revival 2014!

Posted by Armando Brito Mendes | Filed under estatística, matemática, software

Montes de exemplos de R numa única longa página.

Tags: análise de dados, Estat Descritiva, inferência, R-software, software estatístico

## Statistical Associates E-Book Catalog

Posted by Armando Brito Mendes | Filed under data mining, estatística, Investigação Operacional, matemática, materiais ensino

e-books grátis.

TITLE | INFO | DESCRIPTION | EDITION | FREE | KINDLE |

NO PASSWORD REQUIRED FOR TITLES IN THIS SECTION | |||||

2013 Annual Report, Statistical Associates Publishers | Info | Pages: 8. Coverage: General. | 2013 | Free | No Kindle edition |

10 Worst Statistical Mistakes and Pitfalls | Info | Coverage: For selected statistical procedures | 2015 | Free | No Kindle edition |

Creating Simulated Datasets | Info | Pages: 15. Coverage: General, SPSS. | 2012 | Free | No Kindle edition |

Game Theory | Info | Pages: 15. Coverage: General. | 2012 | Free | No Kindle edition |

Probability | Info | Pages: 15. Coverage: General, SPSS, SAS, Stata. | 2013 | Free | No Kindle edition |

Testing Statistical Assumptions | Info | Pages: 51. Coverage: General, SPSS. | 2012 | Free | Coming |

E-MONOGRAPHS: ALL $5 AT AMAZON/KINDLE | |||||

Association, Measures of | Info | Pages: 49. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Correlation | Info | Pages: 60. Coverage: General, SPSS, SAS, Stata. | 2013 | Free | Buy at Amazon |

Correspondence Analysis | Info | Pages: 37. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Crosstabulation | Info | Pages: 60. Coverage: General, SPSS, SAS, Stata. | 2013 | Free | Buy at Amazon |

Curve Fitting & Nonlinear Regression | Info | Pages: 53. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Discriminant Function Analysis | Info | Pages: 52. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Life Tables & Kaplan-Meier Analysis | Info | Pages: 32. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Literature Review in Research and Dissertation Writing | Info | Pages: 52. Coverage: General. | 2013 | Free | Buy at Amazon |

Multidimensional Scaling | Info | Pages: 55. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Network Analysis | Info | Pages: 35. Coverage: General, UCINET. | 2012 | Free | Buy at Amazon |

Ordinal Regression | Info | Pages: 93. Coverage: General, SPSS, SAS, Stata. | 2014 | Free | Buy at Amazon |

Parametric Survival Analysis (Event History Analysis) | Info | Pages: 64. Coverage: General, Stata, SAS. | 2012 | Free | Buy at Amazon |

Partial Correlation | Info | Pages: 40. Coverage: General, SPSS, SAS, Stata. | 2014 | Free | Buy at Amazon |

Path Analysis | Info | Pages: 81. Coverage: General, SPSS AMOS. SAS, Stata. | 2014 | Free | Buy at Amazon |

Power Analysis | Info | Pages: 36. Coverage: General, SPSS SamplePower, G*Power. | 2012 | Free | Buy at Amazon |

Probit Regression & Response Models | Info | Pages: 92. Coverage: General, SPSS. | 2012 | Free | Buy at Amazon |

Research Design | Info | Pages: 53. Coverage: General. | 2013 | Free | Buy at Amazon |

Scales and Measures | Info | Pages: 91. Coverage: General, SPSS, SAS, Stata, WINSTEPS, jMetric | 2013 | Free | Buy at Amazon |

Survey Research & Sampling | Info | Pages: 82. Coverage: General. | 2013 | Free | Buy at Amazon |

Two-Stage Least Squares Regression | Info | Pages: 45. Coverage: General, Stata, SPSS, SAS. | 2013 | Free | Buy at Amazon |

Variance Components Analysis | Info | Pages: 37. Coverage: General, SPSS, SAS. | 2012 | Free | Buy at Amazon |

WLS: Weighted Least Squares Regression | Info | Pages: 54. Coverage: General, SPSS, SAS, Stata. | 2013 | Free |

Tags: motores de busca

## Scholarpedia

Posted by Armando Brito Mendes | Filed under data mining, estatística, matemática, materiais para profissionais, refs bibliográficas

Uma alternativa à weekepedia com suposta melhor qualidade.

Welcome to Scholarpedia

the peer-reviewed open-access encyclopedia,

where knowledge is curated by communities of experts

**Disseminate**: share your expertise with a global audience

**Pioneer**: write the first persistent online review in your area of specialization

**Steward**: supervise the development of articles in your field

**Collaborate**: work with expert scientists and scholars from around the world

**Learn**: gain experience with scholarly writing and editing

**Publish**: transform your writing into a peer-reviewed article

erts

Tags: motores de busca

## Markov Chains explained visually

Posted by Armando Brito Mendes | Filed under Investigação Operacional, matemática, materiais ensino, visualização

Adding on to their series of graphics to explain statistical concepts, Victor Powell and Lewis Lehe use a set of interactives to describe Markov Chains. Even if you already know what Markov Chains are or use them regularly, you can use the full-screen version to enter your own set of transition probabilities. Then let the simulation run.

Tags: grafos, otimização