Efficient Interconnectivity Among Networks Under Security Constraint

Interconnectivity among networks is essential for enhancing communication capabilities of networks such as the expansion of geographical range, higher data rate, etc. However, interconnections may initiate vulnerability (e.g., cyber attacks) to a secure network due to introducing gateways and opportunities for security attacks such as malware, which may propagate from the less secure network. In this paper, the interconnectivity among subnetworks is maximized under the constraint of security risk. The dynamics of propagation of security risk is modeled by the evil-rain influence model and the SIR (Susceptible-Infected-Recovered) epidemic model. Through extensive numerical simulations using different network topologies and interconnection patterns, it is shown that the efficiency of interconnectivity increases nonlinearly and vulnerability increases linearly with the number of interconnections among subnetworks. Finally, parametric models are proposed to find the number of interconnections for any given efficiency of interconnectivity and vulnerability of the secure network

Performance analysis of high efficiency InxGa1−xN/GaN intermediate band quantum dot solar cells

In this subsistent fifth generation era, InxGa1−xN/GaN based materials have played an imperious role and become promising contestant in the modernistic fabrication technology because of some of their noteworthy attributes. On our way of illustrating the performance, the structure of InxGa1−xN/GaN quantum dot (QD) intermediate band solar cell (IBSC) is investigated by solving the Schrödinger equation in light of the Kronig-Penney model. In comparison with p-n homojunction and heterojunction solar cells, InxGa1−xN/GaN IBQD solar cell manifests larger power conversion efficiency (PCE). PCE strongly depends on position and width of the intermediate bands (IB). Position of IBs can be controlled by tuning the size of QDs and the Indium content of InxGa1−xN whereas, width of IB can be controlled by tuning the interdot distance. PCE can also be controlled by tuning the position of fermi energy bands as well as changing the doping concentration. In this work, maximum conversion efficiency is found approximately 63.2% for a certain QD size, interdot distance, Indium content and doping concentration. Keywords: Solar cell, InxGa1−xN/GaN, Quantum dots, Intermediate band(s), Power conversion efficienc

Impacts of Operators’ Behavior on Reliability of Power Grids During Cascading Failures

Human operators play a key role in the reliable operation of critical infrastructures. However, human operators may take actions that are far from optimum. This can be due to various factors affecting the operators\u27 performance in time-sensitive and critical situations such as reacting to contingencies with significant monetary and social impacts. In this paper, an analytic framework is proposed based on Markov chains for modeling the dynamics of cascading failures in power grids. The model captures the effects of operators\u27 behavior quantified by the probability of human error under various circumstances. In particular, the observations from historical data and information obtained from interviews with power-system operators are utilized to develop the model as well as identify its parameters. In light of the proposed model, the noncritical regions of power-system\u27s operating characteristics with human-factor considerations are characterized under which the probability of large cascading failures is minimized