A routing algorithm for reducing optical loss in photonic Networks-on-Chip

Driven by increase in automation, smart homes play an important role in today’s human life. This paper presents a new model for smart home technologies based on multi-device bidirectional visible light communication (VLC). For multiple devices and users, orthogonal code-based wavelength division (color beams) full-duplexed bidirectional VLC link is proposed. The color beams from RGB LEDs are utilized to transmit data and synchronize multi-device transmission. To enhance the performance of the proposed model, receiver diversity is also employed. Performance evaluation reveals that the proposed VLC-based model for smart homes is efficient with superior BER performance in a typical smart home environment except for the far corners. The maximum achievable data rate for each user up to four users is found to be 24 Mbps at both uplink and downlink transmissions.     

A study on dissociation of sII krypton hydrate and the effect of hydrocarbon guest molecules as stabilizer by molecular dynamics simulation

In this paper, the characteristics of structure II krypton hydrate are studied by molecular dynamics simulation under isobaric-isothermal (NPT) ensemble condition. The dissociation process of the hydrate is simulated and the effect of krypton (Kr) and various types of hydrocarbon guest molecules (HGMs) on the stability of the hydrate structure is investigated during the simulation time of 1 ns. The studied HGMs are propane, isobutane, neopentane, cyclopropane, cyclobutane, cyclopentane and cyclopentene. The structural change of the Kr-hydrate is analyzed with the radial distribution function, mean square displacement and diffusion coefficient. As temperature increases, the obtained results indicate a gradual increase in the Kr-hydrate cell size, which leads to distortion of the hydrate lattice and escaping of the encapsulated Kr molecules from the hydrate structure to form small bubbles of Kr aggregated in the aqueous solution.     

Low-cost regional-based congestion-aware routing algorithm for 2D mesh NoC

Given the advantages of network-on-chips (NoCs), they are rapidly improving to replace other forms of System-on-Chip (SoC) designs. Although various factors improve the NoC's performance, many challenges should be addressed when designing an NoC, one of which is congestion and its impacts on performance and efficiency. Hence, numerous routing algorithms have been proposed that contemplate the congestion influences to deal with its complexities. Nevertheless, given the significant impacts of overheads on performance and efficiency, it is crucial to consider them when designing an enhanced NoC. The proposed routing algorithm employs regional traffic information within multiple clusters and has a decent view of the traffic condition when choosing the path to the destination. Each node generates one bit of traffic information and propagates it only when the node is congested, thus preventing the information overhead. Finally, the path diversity parameter is utilized to identify the best route from the source to the destination. The proposed algorithm's results show that the number of received packets, average latency, average throughput, maximum latency, and energy consumption while using different traffic patterns are improved by 10.9%, 35.3%, 15.8%, 43%, and 15.3%, respectively.     

Molecular dynamics simulation for studying the stability of structure H clathrate-hydrates of argon and large guest molecules

The aim of present paper is to study the stability of (argon + large guest molecules) structure H clathrate-hydrates by using molecular dynamics simulations and with employing the COMPASS force field to consider the molecular interactions. The simulations are performed by embedding the structure H clathrate-hydrates in a simulation cell under isobaric-isothermal (NPT) conditions. The obtained equilibrium lattice parameters are compared with the experimental data, where a good consistency is observed. The results show that the size and dipole moment of the guest molecules enclosed in the hydrate cages play the main role in the interactions between the guest molecules and the water molecules, which constitute the surrounding walls of the hydrate cage and these interactions would stabilize the hydrate structure. The characteristics of the clathrate-hydrate structure are analyzed by evaluating the radial distribution function, where the agreement between the results obtained in this work and other similar theoretical and experimental investigations validates the simulation procedure and related interpretations.     

A New BIST-based Test Approach with the Fault Location Capability for Communication Channels in Network-on-Chip

In this paper, a new BIST based test approach to detecting short faults on the communication channels data links in network-on-chip is proposed. The rationale underlying the novelty of the proposed approach is that it is capable of locating the faulty channels while simultaneously performing the testing as well as updating the Routing Tables (RT) in which irregular Mesh-based and fault tolerant NoCs that are using Table-based routing. The proposed approach encompasses TPG and TRA located in the Network Adapter (NA) as well as a Packet Comparing Module (PCM) embedded in the routers. The approach, in addition, with a high scalability leads to 100% Test Coverage (TC) and 82.3% capability of diagnosing faulty channels in NoCs with a high scale. Furthermore, the approach is capable of being performed within one Round (two phase) run with a total time of 70 clocks which is considered as cost-effective compared with the preceding methods. The simulation results demonstrate that the hardware cost of PCM is trivial compared with the hardware of RASoC, HERMES, Æthereal and Vici routers.     

Pure axial flow of viscoelastic fluids in rectangular microchannels under combined effects of electro-osmosis and hydrodynamics

This paper presents an analysis of the combined electro-osmotic and pressure-driven axial flows of viscoelastic fluids in a rectangular microchannel with arbitrary aspect ratios. The rheological behavior of the fluid is described by the complete form of Phan-Thien–Tanner (PTT) model with the Gordon–Schowalter convected derivative which covers the upper convected Maxwell, Johnson–Segalman and FENE-P models. Our numerical simulation is based on the computation of 2D Poisson–Boltzmann, Cauchy momentum and PTT constitutive equations. The solution of these governing nonlinear coupled set of equations is obtained by using the second-order central finite difference method in a non-uniform grid system and is verified against 1D analytical solution of the velocity profile with less than 0.06% relative error. Also, a parametric study is carried out to investigate the effect of channel aspect ratio (width to height), wall zeta potential and the Debye–Hückel parameter on 2D velocity profile, volumetric flow rate and the Poiseuille number in the mixed EO/PD flows of viscoelastic fluids with different Weissenberg numbers. Our results show that, for low channel aspect ratios, the previous 1D analytical models underestimate the velocity profile at the channel half-width centerline in the case of favorable pressure gradients and overestimate it in the case of adverse pressure gradients. The results reveal that the inapplicability of the Debye–Hückel approximation at high zeta potentials is more significant for higher Weissenberg number fluids. Also, it is found that, under the specified values of electrokinetic parameters, there is a threshold for velocity scale ratio in which the Poiseuille number is approximately independent of channel aspect ratio.