Congestion-aware ant colony based routing algorithms for efficient application execution on Network-on-Chip platform

Networks-on-Chip (NoC) is an interesting option in design of communication infrastructures for embedded systems. It provides a scalable structure and balanced communication between the cores. Parallel applications that take advantage of the NoC architectures, are usually are communication-intensive. Thus, a big deal of data packets is transmitted simultaneously through the network. In order to avoid congestion delays that deteriorate the execution time of the implemented applications, an efficient routing strategy must be thought of carefully. In this paper, the ant colony optimization paradigm is explored to find and optimize routes in a mesh-based NoC. The proposed routing algorithms are simple yet efficient. The routing optimization is driven by the minimization of total latency during packets transmission between the tasks that compose the application. The presented performance evaluation is threefold: first, the impact of well-known synthetic traffic patterns is assessed; second, randomly generated applications are mapped into the NoC infrastructure and some synthetic communication traffics, that follow known patterns, are used to simulate real situations; third, sixteen real-world applications of the E3S and one specific application for digital image processing are mapped and their execution time evaluated. In both cases, the obtained results are compared to those obtained with known general purpose algorithms for deadlock free routing. The comparison avers the effectiveness and superiority of the ant colony inspired routing.     

Numerical prediction of flow and heat transfer of power-law fluids in a plane channel with a built-in heated square cylinder

Structure of unsteady laminar flow and heat transfer of power-law fluids in two-dimensional horizontal plane channel with a built-in heated square cylinder is studied numerically. The governing equations are solved using a control volume finite element method (CVFEM) adapted to the staggered grid. Computations are performed over a range of Reynolds and Richardson numbers from Re = 20 to 200 and from Ri = 0 to 8, respectively at fixed Prandtl number Pr = 50 and blockage ratio value β′ = 1/8. Three different values of the power-law index (n = 0.5, 1 and 1.4) are considered in this study to show its effect on the value of the critical Reynolds number defining the transition between two different flow regimes (symmetrical and periodic flows), the variations of Strouhal number, drag and lift coefficients and the heat transfer from the square cylinder as function of Reynolds number. Heat transfer correlations are obtained through forced convection. A discussion about the buoyancy effect on the flow pattern and the heat transfer for different power-law index is also presented.     

Tributyl citrate oligomers as plasticizers for poly (lactic acid): thermo-mechanical film properties and aging

Poly (lactic acid), PLA, is a biodegradable thermoplastic that can be produced from renewable resources. The polymer is of interest for production of films for packaging applications. However, plasticization of PLA is required in order to obtain films with sufficient flexibility. PLA was blended with tributyl citrate (TbC) and two oligomers of TbC that were synthesized by transesterification of tributyl citrate (TbC) and diethylene glycol (DEG). Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) were used to investigate the dynamic mechanical and thermal properties of the blends. All the plasticizers investigated decreased the glass transition temperature of PLA, and the reduction was the largest with the plasticizer having the lowest molecular weight. The PLA matrix became saturated with plasticizer at a certain concentration and phase separation occurred; the higher the molecular weight of the plasticizer, the lower the saturation concentration. Aging of the blends at room temperature for several months induced partial phase separation in the material. It was observed that the morphological stability of the blends was enhanced when the plasticizer concentration was reasonably low, i.e. 10-15 wt%.     

Influence of ageing on the dynamic behaviour and the electrochemical characteristics of a 500 We PEMFC stack

In this study, a 500 We 19 cells Proton exchange membrane fuel cell (PEMFC) stack was aged for ∼1200 h and submitted to current steps between different operating levels. Using two different multi-channel data acquisition systems (one at 100 kHz and one at 1 Hz). the evolution with ageing of individual cells and full stack's short term (∼10 s) and medium term (∼4 min) dynamic performances was followed. Undershoots and overshoots behaviours were observed for respective current step-up and step-down. It appeared that, in studied operating conditions, the first time constant was related to the charge transfer at electrode/electrolyte interfaces. After the first “plateau”, the voltage evolution was explained by a membrane water content evolution.     

Multifold behavior of the information transmission by the quantum 3-switch

Quantum Information Processing - A Correction to this paper has been published: https://doi.org/10.1007/s11128-019-2234-5     

Microstructural evolution and strain hardening of Fe–24Mn and Fe–30Mn alloys during tensile deformation

High Mn steels demonstrate an exceptional combination of high strength and ductility owing to their sustained high work hardening rate during deformation. In the present work, the microstructural evolution and work hardening of Fe–30Mn and Fe–24Mn alloys during uniaxial tensile testing at 293 K and 77 K were investigated. The Fe–30Mn alloy did not undergo significant strain-induced phase transformations or twinning during deformation at 293 K, whereas these transformations were observed during deformation at 77 K. A modified Kocks–Mecking model was successfully applied to describe the strain hardening behavior of Fe–30Mn at both temperatures, and quantitatively identified the influence of stacking fault energy and strain-induced phase transformations on dynamic recovery. The Fe–24Mn alloy underwent extensive ε martensite transformation during deformation at both test temperatures. An analytical micromechanical model was successfully used to describe the work hardening of Fe–24Mn and permitted the calculation of the ε martensite stress–strain curve and tensile properties.     

Distribution of NGF and NT-3-like protein immunoreactivity in the teleost kidney

By means of immunochemistry and immunohistochemistry, we investigated in the kidney of freshwater and marine teleostean species for the presence and localization of three neurotrophins: nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin (NT)-3. In both species studied, NGF-like and NT-3-like immunoreactivity were present in the kidney with different distribution patterns, while BDNF-like immunoreactivity was never detected. In goldfish, NGF-like and NT-3-like immunoreactivity were identified extensively in cells along part of the arterial branches adjacent to the afferent arterioles. In scorpion fish, NGF-like and NT-3-like immunoreactive cells were observed both on afferent arterioles and on adjacent secondary branches derived from renal arteries. No immunoreactivity was detected in other renal structures. A staining pattern of immunoreactivity similar to that obtained for NGF and NT-3 was detected utilizing S100 antibody as a juxtaglomerular (JG) cell marker. Double immunolabellings NGF/S100 and NT-3/S100 evidenced the coexistence of neurotrophin-like proteins and S100-like protein in the same immunoreactive cells, thus identifying them as juxtaglomerular cells. Western blot analysis revealed the presence of molecules immunoreactive to NGF and NT-3, whose molecular weights were very similar to those of the corresponding mammalian neurotrophins. These findings extend the presence and distribution of NGF-like and NT-3-like IR in the kidney to teleost species, suggesting a probable participation of these proteins in the renal functions of freshwater and marine teleosts.