Efficient Algorithms for Solving Size-Shape-Topology Truss Optimization and Shortest Path Problems

Efficient numerical algorithms for solving structural and Shortest Path (SP) problems are proposed and explained in this study. A variant of the Differential Evolution (DE) algorithm for optimal (minimum) design of 2-D and 3-D truss structures is proposed. This proposed DE algorithm can handle size-shape-topology structural optimization. The design variables can be mixed continuous, integer/or discrete values. Constraints are nodal displacement, element stresses and buckling limitations. For dynamic (time dependent) networks, two additional algorithms are also proposed in this study. A heuristic algorithm to find the departure time (at a specified source node) for a given (or specified) arrival time (at a specified destination node) of a given dynamic network. Finally, an efficient bidirectional Dijkstra shortest path (SP) heuristic algorithm is also proposed. Extensive numerical examples have been conducted in this study to validate the effectiveness and the robustness of the proposed three numerical algorithms

Modelling, Verification, and Formal Analysis of Security Properties in a P2P System

International audienceWe present a security analysis of the SPREADS 1 system, a distributed storage service based on a centralized peer-to-peer architecture. We formally modelled the salient behavior of the actual system using ABCD, a high level specification language with a coloured Petri net semantics, which allowed the execution states of the system to be verified. We verified the behavior of the system in the presence of an external Dolev-Yao attacker, unearthing some replay attacks in the original system. Furthermore, since the implementation is also a formal model, we have been able to show that any execution of the model satisfies certain desirable security properties once these flaws are repaired

The effect of quercetin on fertility of frozen-thawed ram epididymal spermatozoa

The aim of the present study was to evaluate the effects of quercetin as an antioxidant supplement on frozen-thawed ram epididymal sperm quality. Quercetin is a type of flavonoid antioxidant that is found in plants, with the ability to scavenge free radicals. Twenty testicles from mature rams were collected from a nearby slaughterhouse immediately after slaughter. Epididymal spermatozoa were recovered from the caudal of epididymides by injecting Bracket and Oliphant's (BO) medium retrogradely through the ductus deferens and extended with a tris egg-yolk-based extender and supplemented with 0, 5, 10, 15, 20, and 50 μg/mL quercetin. Following equilibration, the straws were frozen, and then plunged into liquid nitrogen. After thawing, optimized concentrations of quercetin were defined based on their viabilities and used to assess fertilization and developmental potential. The results showed that the viability of frozen-thawed spermatozoa significantly increased by using 5 and 10 μg/mL quercetin in the freezing extender. However, total and progressive motility of frozen-thawed spermatozoa were not affected by 5 and 10 μg/mL quercetin in comparison with control (0 μg/mL). The mean number of zygote, morula, and blastocyst stage embryos increased significantly by using 5 and 10 μg/mL quercetin compared with other frozen-thawed treatments(P <0.05). However, the blastocyst rate of fresh sperm was significantly higher (P <0.05). In conclusion, to improve the quality of frozen-thawed ram epididymal spermatozoa, 5 and 10 μg/mL quercetin appears to be an attractive option. Further studies are suggested to understand the synergistic effect of quercetin with other antioxidants to improve the ram freezing–thawing process.Keywords: antioxidant, cryopreservation, fertility, freezing extende

Electrodeposited Cobalt-Copper mixed oxides for supercapacitor electrodes and investigation of the Co/Cu ratio on the electrochemical performance

In this study, different Cobalt-Copper mixed oxides compositions for supercapacitor electrodes have been prepared, by means of electrodeposition and thermal annealing. The chemical-physical and electrochemical characterization of electrodes, as well as the effect of different Co/Cu in the ratios on the crystal lattice, electrode morphologies, and electrochemical performance of the electrodes, were investigated using X-ray diffraction (XRD), scanning electron microscopic (SEM) and cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) tests. The results indicated that the electrode prepared from 0.06 M CoSO4 center dot 7H(2)O + 0.04 M CuSO4 center dot 5H(2)O solution (CC4) had a better electrochemical performance. The initial capacity of the CC4 electrode was 28.3 mAh/g at a scan rate of 5 mV/s with a coulombic efficiency of 94%. CC4 electrode featured capacity retention of 79.2% at a constant current density of 1 A/g after 5000 cycles