Optimal resilient threshold GQ signatures

GQ signature scheme is widely used in many cryptographic protocols, such as forward-secure signature scheme, identity-based signature scheme, etc. However, there is no threshold version of this important signature scheme in the open literature. We proposed the first threshold GQ signature scheme. The scheme is proved unforgeable and robust against any adaptive adversary by assuming hardness of computing discrete logarithm modulo a safe prime and existence of fully synchronous broadcast channel. Furthermore, with some modifications, our scheme achieves optimal resilience such that the adversary can corrupt up to a half of the players. As an extension of our work, we provided a threshold identity-based signature scheme and a threshold forward-secure signature scheme, which is the threshold version of the most efficient forward-secure signature scheme up to now.     

Strength prediction of multi-layer plain weave textile composites using the direct micromechanics method

Previously developed micromechanical methods for stiffness and strength prediction are adapted for analysis of multi-layer plain weave textile composites. Utilizing the direct micromechanics method (DMM) via finite element modeling, three methods are presented: (a) direct simulation of a multi-layer plain weave textile composite; (b) micromechanical analysis of a single layer of interest from the force and moment resultants acting on that layer; and (c) application of the previously developed quadratic stress-gradient failure theory to the layer of interest. In comparison to direct modeling, the other two techniques show only 5% difference over a number of random test cases. Several practical design examples of strength prediction are included to illustrate the importance and accuracy of method implementation.     

NUMERICAL INVESTIGATION OF HEAT TRANSFER UNDER CONFINED IMPINGING TURBULENT SLOT JETS

This work numerically in vestigates confined impinging turbulent slot jets. Eight turbulence models, including one standard and seven low-Reynolds-number k-epsilon models, are employed and tested to predict the heat transfer performance of multiple impinging jets. Validation results indicate that the prediction by each turbulence model depends on grid distribution and numerical scheme used in spatial discretization. In addition, spent fluid exits are set between impinging jets to reduce the cross-flow effect in degradation of the heat transfer of downstream impinging jets. The overall heat transfer performance can be enhanced by proper spent fluid removal.     

Performance evaluation of waveguide phase modulators for coherent systems at 1.3 and 1.5 µm

This article describes the fabrication and performance evaluation ofX-cut andZ-cut Ti:LiNbO3traveling wave waveguide phase modulators designed for coherent systems applications at 1.3 and 1.5 μm. Details of device fabrication and measurements of phase shift as a function of optical wavelength, input polarization, modulation voltage, and modulation frequency are reported. Phase modulator performance in a 40-Mbit/s self-heterodyne coherent DPSK experiment is also discussed.     

The n-type Ge photodetectors with gold nanoparticles deposited to enhance the responsivity

Gold nanoparticles (AuNPs) have been deposited on n-type Ge photodetectors to improve the responsivity. Two different coverage ratios, including 10.5 and 30.3% of AuNPs have been prepared, and the fabricated photodetectors are compared with the control sample. The 1,310-nm responsivities at -2 V of the control, 10.5% AuNPs, and 30.3% AuNPs samples are 465, 556, and 623 mA/W, respectively. The AuNPs could increase the responsivities due to the plasmon resonance. The reflectance spectra of these samples have been measured to verify that plasmon resonance contributes to the forward scattering of incident light. The reflectance decreases with AuNP deposition, and a denser coverage results in a smaller reflectance. The smaller reflectance indicates more light could penetrate into the Ge active layer, and it results in a larger responsivity.     

Optimization of turning operations with multiple performance characteristics using the Taguchi method and Grey relational analysis

This study investigated the optimization of CNC turning operation parameters for SKD11 (JIS) using the Grey relational analysis method. Nine experimental runs based on an orthogonal array of Taguchi method were performed. The surface properties of roughness average and roughness maximum as well as the roundness were selected as the quality targets. An optimal parameter combination of the turning operation was obtained via Grey relational analysis. By analyzing the Grey relational grade matrix, the degree of influence for each controllable process factor onto individual quality targets can be found. The depth of cut was identified to be the most influence on the roughness average and the cutting speed is the most influential factor to the roughness maximum and the roundness. Additionally, the analysis of variance (ANOVA) is also applied to identify the most significant factor; the depth of cut is the most significant controlled factors for the turning operations according to the weighted sum grade of the roughness average, roughness maximum and roundness.     

Buckling analysis of skew laminate plates subjected to uniaxial inplane loads

Elastic stability of skew composite laminate plates subjected to uniaxial inplane compressive forces has been studied. The critical buckling loads of the skew laminate plates are carried out by the bifurication buckling analysis implemented in finite element program ABAQUS. The effects of skew angles, laminate layups, plate aspect ratios, plate thicknesses, central circular cutouts, and edge conditions on the buckling resistance of skew composite laminate plates are presented.     

Nb3Si films with zero resistance Tc at 11.9 K fabricated by sputtering Nb on Si substrates

Dendritic textured Nb₃Si thin films, deposited by sputtering pure niobium onto silicon substrates, exhibit a rather high zero-resistance critical temperature, T_c. X-ray and TEM measurements reveal the films to be polycrystalline with the A15 phase. The resistance begins to drop sharply at a temperature of 13.3 K and down to zero at 11.9 K without residual resistivity.     

Influence of fire ignition locations on the actuation of smoke detectors and wet-type sprinklers in a furnished office

Experiments were conducted in a full-scale model office equipped with movable and fixed fire loads to explore the influence of ignition source (movable fire load(s)) conditions on smoke detector and sprinkler actuation. The interior plan dimension is 5.7 m × 4.7 m and the net ceiling height is 3.3 m. Both northeast and southeast wings have a 2.1 m × 0.9 m single door to be opened. Seven fire scenarios (seven different ignited fire load configurations) under natural ventilation were investigated experimentally. The results show that the amount of fire load at the initial stage in a room fire does not markedly affect smoke generation and does not significantly impact the actuation time of the smoke detectors. When the fire source is located near a corner, the plume corner effect greatly increases; smoke detectors and sprinklers can activate quickly and effectively actuate the fire suppression. When the fire source is located in the room's center, given the uncertainty regarding smoke detector and sprinkler actuation, it may not be possible to control the fire spread.