Security analysis of an audio data encryption scheme based on key chaining and DNA encoding

Multimedia Tools and Applications - Fairly recently, a new audio encryption scheme has been proposed. The cryptosystem is based on a substitution-permutation algorithm using DNA encoding. The...     

Breaking an image encryption scheme based on Arnold map and Lucas series

Multimedia Tools and Applications - Recently, a novel image encryption based on Arnold scrambling and Lucas series has been proposed in the literature. The scheme design is based on...     

A Service-Oriented Middleware for Building Collaborative UAVs

For a while, Unmanned Arial Vehicles (UAVs) use was limited to military applications, however recently UAVs are also used for a wide range of civilian applications. Some of these UAV applications may involve multiple UAVs that must cooperate to achieve a common goal. This kind of applications is termed collaborative UAV applications. This paper investigates the collaborative aspects and challenges of multiple UAV systems. One of the main issues for multiple UAV systems is developing an effective framework to enable the development of software systems for collaborative UAV operations. One possible approach is to rely on service-oriented computing and service-oriented middleware technologies to simplify the development and operations of such applications. This paper discusses how the service-oriented middleware approach can help resolve some of the challenges of developing collaborative UAVs. The paper also proposes a service-oriented middleware architecture that can satisfy the development and operations of such applications.     

First principle studies of structural, elastic, electronic and optical properties of Zn-chalcogenides under pressure

Structural, elastic, electronic and optical properties ofzinc-chalcogenides （viz. ZnX, X = S, Se and Te） are studied in zinc-blende structure under hydrostatic pressure using the full-potential linearized augmented plane wave method. Generalized gradient approximation is used for exchange correlation potentials. Pressure-dependent lattice constants and bulk moduli are obtained using the optimization method. Young＇s modulus, Poisson＇s ratio, internal strain parameter and anisotropy are also calculated. The higher values of Young＇s modulus in comparison to the bulk modulus show that these materials are hard to break. Poisson＇s ratio is computed for the first time for these materials to the best of our knowledge and its values show higher ionic contribution in these materials. Modified Becke and Johnson （mBJ） method is used to study band gaps, density of states, dielectric function and refractive index. Electronic study shows direct band gaps convert to indirect band gaps with increasing pressure in the case of ZnS and ZnTe. We compared our results with other theoretical and experimental results. Our results are far better than other theoretical results because mBJ is the best technique to treat Ⅱ-Ⅵ semiconductors.     

A novel scheme to improve fault-tolerant capabilities of multistage interconnection networks

In this paper, we propose a novel augmenting and partitioning scheme for constructing multistage interconnection networks (MINs) with improved fault-tolerant capabilities. We first propose a partitioning scheme to construct and analyze partitioned MINs (PMINs). A simulation method is developed, based on the stuck-at fault model, to evaluate dynamic full access (DFA) and average number of passes in PMINs. We then propose an augmenting scheme to construct augmented partitioned MINs (APMINs) with further enhanced fault-tolerant capabilities. Simulation analysis of APMINs, based on the switch level fault model, showed that the proposed scheme significantly improves the fault-tolerant capability of MINs. Finally, the effectiveness of the proposed scheme is evaluated with respect to cost, DFA, locality, and average path length. This revised version was published online in June 2006 with corrections to the Cover Date.     

New iterative linear matrix inequality based procedure for H2 and H∞ state feedback control of continuous‐time polytopic systems

This article provides new linear matrix inequality (LMI) sufficient conditions for a generalized robust state feedback control synthesis problem for linear continuous‐time polytopic systems. This generalized problem includes the robust stability, H₂ ‐norm, and H_∞ ‐norm problems as special cases. Using a novel general separation result, which separates the state feedback gain from the Lyapunov matrix but with the state feedback gain synthesized from the slack variable, then allows the formulation of LMI sufficient conditions for the generalized problem. Compared to existing parameterized LMI based conditions, where auxiliary scalar parameters are introduced in order to include the quadratic stability conditions (ie, assuming a constant Lyapunov matrix) as a special case, the proposed new conditions are true LMIs and contain as a particular case the optimal quadratic stability solution. Utilizing any initial solution derived by the quadratic or some existing methods as a starting solution, we propose an algorithm based on an iterative procedure, which is recursively feasible in each update, to compute a sequence of nonincreasing upper bounds for the H₂ ‐norm and H_∞ ‐norm. In addition, if no feasible initial solution can be found for some uncertain systems using any existing methods, another algorithm is presented that offers the possibility of obtaining a robust stabilizing gain. Numerical examples from the literature demonstrate that our algorithms can provide less conservative results than existing methods, and they can also find feasible solutions where all other methods fail.     

Extracting parameters of OFET before and after threshold voltage using genetic algorithms

This paper presents a compact analytical model for the organic field-effect transistors(OFETs), which describes two main aspects, the first one is related to the behavior in above threshold regime, while the other corresponds to the below threshold regime.The total drain current in the OFET device is calculated as the sum of two components, with the inclusion of a smooth transition function in order to take into account both regions using a single expression. A genetic algorithm based approach(GA) is investigated as a parameter extraction tool in the case of the compact OFET model to find the parameters values from experimental data such as:mobility enhancement factor γ, threshold voltage VT h, subthreshold swing S, channel length modulation λ, and knee region sharpness m. The comparison of the developed current model with the experimental data shows a good agreement in terms of the transfer and the output characteristics. Therefore, the GA based approach can be considered as a competitive candidate compared to the direct method.     

Synthesis and Characterization of Bulk Bi-2212 Superconducting Ceramic Using Photopolymerization Reaction-Based Method

Journal of Superconductivity and Novel Magnetism - This study highlights the synthesis of Bi2Sr2CaCu2O8 (Bi-2212) superconducting ceramic using the photopolymerization reaction (PPR) and...     

Efficient surrogate method for predicting pavement response to various tire configurations

A computationally efficient surrogate model was developed based on artificial neural networks (ANN) to investigate the effect of the new generation of wide-base tires on pavement responses. Non-uniform tire contact stress measurements were obtained using a stress-in-motion instrument. The measured 3-D contact stresses were applied on two extreme 3-D flexible pavement finite element models representing low-volume (thin) and high-volume (thick) roads. Eleven critical pavement responses were modeled at two different material properties input levels—detailed and simplified—depending on data availability. The results rendered by the ANN surrogate models were highly accurate with average prediction error less than 5 % and R-square values higher than 0.95. In addition, two sensitivity analyses were performed to investigate the variables effect on pavement responses. It was found that the type of tire (wide-base vs. dual tire assembly) is more influential than the inflation pressure on pavement responses. However, the tire inflation pressure seemed to have a significant effect on near-surface responses. The developed models were incorporated into a tool to assist designers and engineers in investigating the effect of the pavement responses of wide-base versus dual tire assembly under typical loading conditions and pavement structures.

     

Regional gradient observability for semilinear hyperbolic systems: HUM approach

The paper aims to extend the notion of regional observability of the gradient to the semilinear hyperbolic case, in order to reconstruct the gradient of the initial conditions in a subregion $omega$ of the domain evolution $varOmega$. We start with an asymptotically linear system, the approach is based on an extension of the Hilbert uniqueness method (HUM) and Schauder''s fixed point theorem. The analysis leads to an algorithm which is successfully numerically implemented and illustrated with examples and simulations.