Security in Wireless Sensor Networks: Issues and Challenges

Wireless Sensor Network (WSN) is an emerging technology that shows great promise for various futuristic applications both for mass public and military. The sensing technology combined with processing power and wireless communication makes it lucrative for being exploited in abundance in future. The inclusion of wireless communication technology also incurs various types of security threats. The intent of this paper is to investigate the security related issues and challenges in wireless sensor networks. We identify the security threats, review proposed security mechanisms for wireless sensor networks. We also discuss the holistic view of security for ensuring layered and robust security in wireless sensor networks.Comment: 6 page

The Investigation of Stability of Tunnels and Settlements with Centrifuge Modeling

In most of the larger cities underground transportation systems have been gettingdesired. Such systems are constructed in urban areas and involve a tunnel, especially in softground and in shallow zones.One of major concerns for tunneling operations in urban area is the effect onneighboring buildings, because the tunneling operation and near structures highly interacteach other. Whatever the used construction method is, the excavation of a tunnel causesdisplacement around the opening and may expand towards the ground surface. Thedislocations of the buildings interact with the ground movement, and the rigidity of existingstructures will promote reduction of the magnitude of displacements induced by tunneling.In this investigation, to determine displacements induced by tunneling, the centrifugemodeling was used. The small scale centrifuge model provided dependable information aboutthe face collapse of a shallow tunnel. A required support pressure for shield driven tunnels insoft materials, and the ground deformations along the longitudinal section of the tunnelmodel, can be identified by simulating a loss of tunnel face stability

Cyber Threats and NATO 2030: Horizon Scanning and Analysis

The book includes 13 chapters that look ahead to how NATO can best address the cyber threats, as well as opportunities and challenges from emerging and disruptive technologies in the cyber domain over the next decade. The present volume addresses these conceptual and practical requirements and contributes constructively to the NATO 2030 discussions. The book is arranged in five short parts...All the chapters in this book have undergone double-blind peer review by at least two external experts.https://scholarworks.wm.edu/asbook/1038/thumbnail.jp

2,3-Dibromo-1-[4-(2,3-dibromo-4,5-di­meth­oxy­benz­yl)-2,5-dimeth­oxy­benz­yl]-4,5-dimeth­oxy­benzene

The mol­ecule of the title compound, C26H26Br4O6, is located around a crystallographic inversion center. The dihedral angle between the central benzene ring and the outer benzene ring is 89.26 (1)°

Lender forbearance

We use a threshold-based design to study ex post discretion in lenders’ contractual enforcement of covenant violations. At preset thresholds, lenders enforce contractual breaches only infrequently, but this enforcement is associated with material consequences, e.g., fees and renegotiations. Enforcement varies significantly over time and peaks when credit conditions are tightest, indicating that enforcement is procyclical. Costly coordination reduces enforcement: syndicates with ex ante restrictive voting requirements enforce at lower rates. Consistent with theories of lender competition and implicit contracting, enforcement rates are lower for borrowers with access to alternative sources of financing and well-reputed lead arrangers

Metric fluctuations and decoherence

Recently a model of metric fluctuations has been proposed which yields an effective Schr\"odinger equation for a quantum particle with a modified inertial mass, leading to a violation of the weak equivalence principle. The renormalization of the inertial mass tensor results from a local space average over the fluctuations of the metric over a fixed background metric. Here, we demonstrate that the metric fluctuations of this model lead to a further physical effect, namely to an effective decoherence of the quantum particle. We derive a quantum master equation for the particle's density matrix, discuss in detail its dissipation and decoherence properties, and estimate the corresponding decoherence time scales. By contrast to other models discussed in the literature, in the present approach the metric fluctuations give rise to a decay of the coherences in the energy representation, i. e., to a localization in energy space.Comment: 7 page

Immobilization of catalase via adsorption into natural and modified active carbon obtained from walnut in various methods

In the present work, the immobilization of catalase into natural active carbon and active carbon modified by hydrochloric acid was carried out. In the experimental section, the effects of pH, ionic strength andreaction temperature were chosen as parameters, with experiments performed in batch system. For the optimization of immobilization procedure, values of kinetic parameters were evaluated. It was observedthat storage and operational stabilities of the enzyme increased with immobilization. The results obtained from experiments showed that active carbon is a valuable support for the adsorption of enzymes

Space--time fluctuations and the spreading of wavepackets

Using a density matrix description in space we study the evolution of wavepackets in a fluctuating space-time background. We assume that space-time fluctuations manifest as classical fluctuations of the metric. From the non-relativistic limit of a non-minimally coupled Klein-Gordon equation we derive a Schr\"odinger equation with an additive gaussian random potential. This is transformed into an effective master equation for the density matrix. The solutions of this master equation allow to study the dynamics of wavepackets in a fluctuating space-time, depending on the fluctuation scenario. We show how different scenarios alter the diffusion properties of wavepackets.Comment: 11 page

Boundary Effects in Local Inflation and Spectrum of Density Perturbations

We observe that when a local patch in a radiation filled Robertson-Walker universe inflates by some reason, outside perturbations can enter into the inflating region. Generally, the physical wavelengths of these perturbations become larger than the Hubble radius as they cross into the inflating space and their amplitudes freeze out immediately. It turns out that the corresponding power spectrum is not scale invariant. Although these perturbations cannot reach out to a distance inner observer shielded by a de Sitter horizon, they still indicate a curious boundary effect in local inflationary scenarios.Comment: 11 pages, 8 figures, revtex4, v4: minor typos corrected, twocolumn versio