Ocular recognition databases and competitions: a survey

The use of the iris and periocular region as biometric traits has been extensively investigated, mainly due to the singularity of the iris features and the use of the periocular region when the image resolution is not sufficient to extract iris information. In addition to providing information about an individual’s identity, features extracted from these traits can also be explored to obtain other information such as the individual’s gender, the influence of drug use, the use of contact lenses, spoofing, among others. This work presents a survey of the databases created for ocular recognition, detailing their protocols and how their images were acquired. We also describe and discuss the most popular ocular recognition competitions (contests), highlighting the submitted algorithms that achieved the best results using only iris trait and also fusing iris and periocular region information. Finally, we describe some relevant works applying deep learning techniques to ocular recognition and point out new challenges and future directions. Considering that there are a large number of ocular databases, and each one is usually designed for a specific problem, we believe this survey can provide a broad overview of the challenges in ocular biometrics.

     

NUMERICAL SOLUTIONS OF FLOWS IN ROCKET ENGINES WITH REGENERATIVE COOLING

A one-dimensional mathematical model is presented for flows in a rocket engine that has a regenerative cooling system. The problem involves the flow of a gas in a converging- diverging nozzle, the flow of a coolant in channels distributed around the engine, and the heat conduction through a wall between the gas and the coolant. The numerical model adopted is based on the finite-volume method with a second-order scheme. It was noted that it is important to use variable properties in order to predict the maximum wall temperature in the rocket engine and the drop in pressure of the coolant as it moves along the channels, whereas the thrust of the engine can be calculated with constant properties.     

Thermal performance evaluation of a low-cost housing prototype made with plywood panels in Southern Brazil

Although the Brazilian Federal Government has been increasing investments in the housing sector since 2004, there has been a significant increase in the housing deficit as well. In 2007 this deficit had already reached 7.2 million dwellings. The majority (84%) consists of families with monthly income under three minimum wages. However, none of the traditional lines of credit considers families up to that monthly income level for building their own dwellings. In 2004, a program was created to subsidize low-cost housing (“Programa de Subsídio à Habitação de Interesse Social – PSH”) with a maximum subsidy of about US$ 2500 for the construction of ‘do-it-yourself’ units. The present research had the general purpose of conceiving, constructing and evaluating the performance of a low-cost prototype consisting of wood and plywood panels. The object of analysis in this case study was a building prototype located in Canoinhas, in the South of Brazil (26°10′38″S, altitude 765 m above sea level), which was built within the scope of a program for subsidized low-cost housing. The present paper is concerned with evaluating the thermal performance of the finished prototype by means of onsite measurements and performing computer simulations for testing improvements of the original building prototype. From obtained results, general guidelines were drawn for improving indoor comfort conditions.     

Simplified method for yearlong thermal analysis of building prototypes

The paper presents the thermal analysis of a low-cost prototype consisting of plywood panels, which was designed and built by one of the authors within the scope of a program for subsidized low-cost housing. The object of analysis is a building prototype located in Canoinhas, in the South of Brazil (26°10′38″S, altitude 765 m above sea level). The present paper is concerned with evaluating the thermal performance of the prototype over given periods of the year by means of onsite measurements and indoor temperature predictions for the various rooms of the building prototype. From obtained results, the overall performance of the building as well as the individual performance of each room was evaluated.