A simplified orthotropic formulation of the viscoplasticity theory based on overstress

An orthotropic, small strain viscoplasticity theory based on overstress is presented. In each preferred direction the stress is composed of time (rate) independent (or plastic) and viscous (or rate dependent) contributions. Tension-compression asymmetry can depend on direction and is included in the model. Upon a proper choice of a material constant one preferred direction can exhibit linear elastic response while the other two deform in a viscoplastic manner

Biometric privacy protection : guidelines and technologies

Compared with traditional techniques used to establish the identity of a person, biometric systems offer a greater confidence level that the authenticated individual is not impersonated by someone else. However, it is necessary to consider different privacy and security aspects in order to prevent possible thefts and misuses of biometric data. The effective protection of the privacy must encompass different aspects, such as the perceived and real risks pertaining to the users, the specificity of the application, the adoption of correct policies, and data protection methods as well. This chapter focuses on the most important privacy issues related to the use of biometrics, it presents actual guidelines for the implementation of privacy-protective biometric systems, and proposes a discussion of the methods for the protection of biometric data

Obfuscated Fuzzy Hamming Distance and Conjunctions from Subset Product Problems

We consider the problem of obfuscating programs for fuzzy matching (in other words, testing whether the Hamming distance between an $n$-bit input and a fixed $n$-bit target vector is smaller than some predetermined threshold). This problem arises in biometric matching and other contexts. We present a virtual-black-box (VBB) secure and input-hiding obfuscator for fuzzy matching for Hamming distance, based on certain natural number-theoretic computational assumptions. In contrast to schemes based on coding theory, our obfuscator is based on computational hardness rather than information-theoretic hardness, and can be implemented for a much wider range of parameters. The Hamming distance obfuscator can also be applied to obfuscation of matching under the $\ell_1$ norm on $\mathbb{Z}^n$. We also consider obfuscating conjunctions. Conjunctions are equivalent to pattern matching with wildcards, which can be reduced in some cases to fuzzy matching. Our approach does not cover as general a range of parameters as other solutions, but it is much more compact. We study the relation between our obfuscation schemes and other obfuscators and give some advantages of our solution

JOURNAL OF ENVIRONMENTAL MANAGEMENT

Production of porous clay bricks lightened by adding olive mill waste as a pore making additive was investigated. Factors influencing the brick manufacturing process were analyzed by an experimental design, Taguchi method, to find out the most favorable conditions for the production of bricks. The optimum process conditions for brick preparation were investigated by studying the effects of mixture ratios (0, 5 and 10 wt%) and firing temperatures (850, 950 and 1050 degrees C) on the physical, thermal and mechanical properties of the bricks. Apparent density, bulk density, apparent porosity, water absorption, compressive strength, thermal conductivity, microstructure and crystalline phase formations of the fired brick samples were measured. It was found that the use of 10% waste addition reduced the bulk density of the samples up to 1.45 g/cm(3). As the porosities increased from 30.8 to 47.0%, the compressive strengths decreased from 36.9 to 10.26 MPa at firing temperature of 950 degrees C. The thermal conductivities of samples fired at the same temperature showed a decrease of 31% from 0.638 to 0.436 W/mK, which is hopeful for heat insulation in the buildings. Increasing of the firing temperature also affected their mechanical and physical properties. This study showed that the olive mill waste could be used as a pore maker in brick production. (C) 2016 Elsevier Ltd. All rights reserved

DOE and ANN models for powder

Design of expts. (DOE) and artificial neural network techniques (ANN) were used to study packing of fused alumina powders composed of three different sizes of particles. Two techniques have been used for prediction of powder compact porosities in mixts. of three different-sized fused alumina powders. The first is the mixt. design technique that produces a polynomial model of the powder-packing system. The second is the ANN technique that is extensively used to model complex systems in many fields. Three sizes (3, 30, and 350 .mu.m) of fused alumina powder were mixed and uniaxially compacted in the form of cylindrical pellets to measure their packing ability in the green state. Porosities of the cylindrical pellets were generated by prepg. powder mixts. in such proportions that were planned using mixt. design, which is a DOE method. A multilayer feed-forward back-propagation learning algorithm was used as an ANN tool to predict porosity, which was the response variable. Based on the training data, an ANN model of porosity as a function of constituent mix proportions was created with low av. error levels (2.7%). The results indicated that the mixt. model and the ANN model provided good predictions for powder packing

Influence of tea waste concentration in the physical, mechanical and thermal properties of brick clay mixtures

The sustainability of raw materials used in construction industry consumed large quantities of material has great importance. The use of pore-makers in the brick production is reducing the consumption of clean clay resources as well as lightness of the baked brick body. Many organic or inorganic additives have been used as pore-making in brick production for improving thermal performance. In this study, tea waste (TW) were used at different concentrations in the brick clay mixtures to examine its effects on baked brick properties. In addition to micro-structure investigations, physical, mechanical and thermal properties of bricks produced were investigated. It is concluded that tea waste additive up to 10% in brick body can be used for structural application and isolation while ratios more 10% tea waste additive for only isolation purposes. Tea wastes can be used as a pore-making additive in the brick production. © 2019 Elsevier Lt

Levels in patients with Behcet's disease

Annual European Congress of Rheumatology -- JUN 08-11, 2005 -- Vienna, AUSTRIAWOS: 00022990910124