Evaluation of probability mass function of flow in a communication network considering a multistate model of network links

This paper presents two efficient algorithms for exact evaluation of probability mass function (pmf) from source node to sink node of a large communication network considering a multistate capacity model of links, using composite path and composite cut methods. The capacities of various states of each link of the network are assumed to be mutually exclusive. From the pmf the performance index is obtained without difficulty. The applicability of the proposed algorithms has been tested for various networks (two-state and multistate). However, the latter method (composite cut) is found to be more efficient. An interesting finding is that when a three-state model is replaced by an analogous two-state model, system reliability is underestimated. Thus, if a system is to be represented by a multistate model, one should not use a simplified two-state model for mathematical convenience alone.     

A Context-Sensitive Technique for Unsupervised Change Detection Based on Hopfield-Type Neural Networks

In this paper, we propose a context-sensitive technique for unsupervised change detection in multitemporal remote sensing images. This technique is based on a modified Hopfield neural network architecture designed to model spatial correlation between neighboring pixels of the difference image produced by comparing images acquired on the same area at different times. Each spatial position in the considered scene is represented by a neuron in the Hopfield network that is connected only to its neighboring units. These connections model the spatial correlation between neighboring pixels and are associated with a context-sensitive energy function that represents the overall status of the network. Change detection maps are obtained by iteratively updating the output status of the neurons until a minimum of the energy function is reached and the network assumes a stable state. A simple heuristic thresholding procedure is presented and adopted for initializing the network. The proposed change detection technique is unsupervised and distribution free. Experimental results carried out on two multispectral and multitemporal remote sensing images confirm the effectiveness of the proposed technique     

An improved stability result for linear time-delay system using a new Lyapunov–Krasovskii functional and extended reciprocally convex inequality

This paper is concerned with the stability analysis of a linear system with interval time-varying delay using an augmented Lyapunov–Krasovskii (LK) functional approach. A delay-dependent stability criterion is developed in LMI framework to estimate the maximum allowable bound of the time-delay within which the system remains asymptotically stable in the sense of Lyapunov. Conservatism in the proposed delay-dependent stability analysis is reduced by introducing a new LK functional along with the Wirtinger's inequality and extended reciprocally convex matrix inequality. Finally, two numerical examples and the load frequency control problem have been solved to validate the superiority of the proposed stability criterion compared to existing literature.     

Energy transfer between lead sulfide quantum dots in the liquid phase

Förster resonant energy transfer (FRET) from smaller sized PbS Quantum Dots (QDs) to larger sized ones occurs in the liquid phase when adjacent QDs are brought in close proximity by the bridging action of the two SH groups in aromatic or aliphatic dithiols. Signatures of FRET were observed by the lowering of the fluorescence peak corresponding to the smaller particle group and intensification of the peak corresponding to the larger particle group in a mixture of the two in the liquid phase. The suspensions of the two QDs size distributions were mixed in a ratio such that total surface area of the smaller QDs was equal to that of the larger QDs. A 10–13% size deviation in each PbS QDs group also allows this phenomenon to be observed in these samples and is manifested by red-shift and broadening of the fluorescence peak. The ratio of the absorption peak intensity corresponding to the two groups of PbS QDs in the mixture remains the same.     

P-AODV: A Priority Based Route Maintenance Process in Mobile Ad Hoc Networks

Wireless Personal Communications - We present a route maintenance mechanism, P-AODV, which repairs a route by selecting a neighbor on the basis of the traffic being handled by it. A new parameter,...     

The Development of a Processing Window for the Continuous Galvanizing of a Mn–Cr–Si Martensitic Steel

Martensitic or complex phase steels are leading candidates for automotive impact management applications. However, achieving high strengths while obtaining high quality coatings via continuous galvanizing is a challenge due to cooling rate limitations of the processing equipment and selective oxidation of alloying elements such as Cr, Mn, and Si adversely affecting reactive wetting. The galvanizability of a Cr? Mn? Si steel with a target tensile strength above 1250 MPa was investigated within the context of the continuous galvanizing line. The continuous cooling transformation behavior of the candidate alloy was determined, from which intercritical and austenitic annealing thermal cycles were developed. The evolution of substrate surface chemistry and oxide morphology during these treatments and their subsequent effect on reactive wetting during galvanizing were characterized. The target strength of 1250 MPa was achieved and high quality coatings produced using both intercritical (75% γ) and austenitic (100% γ) annealing using a conventional 95%N₂–5%H₂, ?30°C dew point process atmosphere and 0.20 wt% dissolved (effective) Al bath, despite the presence of significant Mn and Cr oxides on the substrate surfaces. It is proposed that complete reactive wetting by the Zn(Al, Fe) bath was promoted by in situ aluminothermic reduction of the Mn and Cr‐oxides by the dissolved bath Al.     

Analytical solution of groundwater waves in unconfined aquifers with sloping boundary

A new analytical solution is derived for tide-driven groundwater waves in coastal aquifers using higher-order Boussinesq equation. The homotopy perturbation solution is derived using a virtual perturbation approach without any pre-defined physical parameters. The secular term removal is performed using a combination of parameter expansion and auxiliary term. This approach is unique compared with existing perturbation solutions. The present first-order solution compares well with the previous analytical solutions and a 2D FEFLOW solution for a steep beach slope. This is due to the fact that the higher-order Boussinesq equation captures the streamlines better than ordinary Boussinesq equation based on Dupuit’s assumption. The slope of the beach emerges as an implicit physical parameter from the solution process.     

Hybrid crosstalk aware Q-Factor analysis for selection of optical virtual private network connection

The presence of physical layer impairments (PLIs) in high-speed optical virtual private network (OVPN) over wavelength-division multiplexing/ dense-wavelength division multiplexing network degrades the connection quality (CQ). The quality can be numerically expressed as the quality factor (Q-Factor) of the connection. The CQ can be further affected by the increasing demand of connections and data speed. It is important to have an efficient OVPN control manager (OVPNCM) to maintain the CQ. OVPNCM can ensure better quality of transmission to the OVPN clients. Traditional routing and wavelength assignment (RWA) algorithms have less regards to the PLIs and cannot provide guaranteed OVPN connection (OVPNC) quality. In order to achieve a guaranteed CQ, we proposed a wavelength assignment (WA) scheme and a hybrid crosstalk model based on linear in-band and nonlinear four-wave mixing crosstalk. The performance of the proposed WA scheme with the hybrid crosstalk model is demonstrated. The results show that the proposed hybrid crosstalk model with WA scheme not only provides a guaranteed OVPNC, but also improves the OVPN performance in terms of blocking probability.     

Two-step orthogonal-state-based protocol of quantum secure direct communication with the help of order-rearrangement technique

The Goldenberg–Vaidman (GV) protocol for quantum key distribution uses orthogonal encoding states of a particle. Its security arises because operations accessible to Eve are insufficient to distinguish the two states encoding the secret bit. We propose a two-particle cryptographic protocol for quantum secure direct communication, wherein orthogonal states encode the secret, and security arises from restricting Eve from accessing any two-particle operations. However, there is a non-trivial difference between the two cases. While the encoding states are perfectly indistinguishable in GV, they are partially distinguishable in the bipartite case, leading to a qualitatively different kind of information-versus-disturbance trade-off and also options for Eve in the two cases.