A stochastic approach for dynamic soil-pile interaction under enviromental effects.

The paper deals with a computational stochastic approach for the unilateral contact problem of dynamic soil-pile interaction. Unilateral contact effects due to tensionless soil capacity, soil elastoplastic-fracturing behaviour and gapping are strictly taken into account, as well as environmental effects under uncertainty decreasing the soil resistance. The proposed methodology concerns the treatment of both, the deterministic and the probabilistic problem. The numerical approach concerning the deterministic problem is based on a double discretization, in space by the Finite Element Method combined with Boundary Element Method, and in time, and on nonconvex optimization. Uncertainties concerning the input parameter values are treated by the Monte Carlo method in the probabilistic problem section. Finally, the proposed methodology is applied for a practical case of dynamic soil-pile interaction

Progressive Collapse of Existing RС Structures due to Environmental Effects: A Numerical Approach for Strengthening by Ties

Existing old reinforced concrete (RC) buildings are sometimes subjected to obligatory removal of some structural element‐members, e.g. columns, and so to the risk of a progressive collapse. This happens due to various reasons, which can concern changes of serviceability and requirements, or environmental effects which cause strength degradation etc. In order to avoid such a progressive collapse, a modification of the structural response and a redistribution of internal actions can result to a requirement for strengthening the remaining structure after the removal of the degraded elements. The present study deals with such a case, which concerns the computational analysis of framed RC structures under the removal of some columns and the so‐induced requirement of a strengthening by ties (tension only elements). The unilateral behaviour of these cable‐ties, which can undertake only tension, is strictly considered, and the response of the remaining historic structure strengthened by ties is computed. Finally, in a practical case of a framed RC structure, the effectiveness of the proposed methodology is shown.ABSTRACTS ХІХ МЕЖДУНАРОДНА НАУЧНА КОНФЕРЕНЦИЯ ПО СТРОИТЕЛСТВО И АРХИТЕКТУРА ВСУ'2019 се организира със съдействието на Фонд "Научни изследвания" с договор за съфинансиране № КП‐06‐МНФ/34. Editors: Vanyo Georgiev, Assoc. Prof. PhD Aleksandra Ivanova, Assoc. Prof. PhD artist Ventsislav Stoyanov, Assoc. Prof. PhD Eng. Yulia Ilieva, Assoc. Prof. PhD Architec

FPGA-based performance analysis of stream ciphers ZUC, Snow3g, Grain V1, Mickey V2, Trivium and E0

In this paper, the hardware implementations of six representative stream ciphers are compared in terms of performance, consumed area and the throughput-to-area ratio. The stream ciphers used for the comparison are ZUC, Snow3g, Grain V1, Mickey V2, Trivium and E0. ZUC, Snow3g and E0 have been used for the security part of well known standards, especially wireless communication protocols. In addition, Grain V1, Mickey V2 and Trivium are currently selected as the final portfolio of stream ciphers for Profile 2 (Hardware) by the eStream project. The designs were implemented by using VHDL language and for the hardware implementations a FPGA device was used. The highest throughput has been achieved by Snow3g with 3330 Mbps at 104 MHz and the lowest throughput has been achieved by E0 with 187 Mbps at 187 MHz. Also, the most efficient cipher for hardware implementation in terms of throughput-to-area ratio is Mickey V2 cipher while the worst cipher for hardware implementation is Grain V1. © 2012 Elsevier B.V. All rights reserved