On Computing Shannon’s Sphere Packing Bound and Applications

file: :home/zaki/.local/share/data/Mendeley Ltd./Mendeley Desktop/Downloaded/Ahmed, Ambroze, Tomlinson - 2007 - On Computing Shannon’s Sphere Packing Bound and Applications.pdf:pdf keywords: SPB mendeley-tags: SPBA new method to numerically evalu- ate Shannon’s lower bound is presented in this pa- per. This new method is based on the Incomplete Beta function and permits the exact evaluation of the Sphere Packing Bound for a large range of code sizes, rates and probability of error. Comparisons with cur- rent standards (DVB–RCS, DVB–S2 and 3GPP) are also presented and discussed. It is shown that cur- rent standard coding schemes are about 0.6dB from the Shannon Limit corrected for Binary Signalling

Scotogenic A4A_4 Neutrino Model for Nonzero θ13\theta_{13} and Large δCP\delta_{CP}

Assuming that neutrinos acquire radiative seesaw Majorana masses through their interactions with dark matter, i.e. scotogenic from the Greek 'scotos' meaning darkness, and using the non-Abelian discrete symmetry $A_4$, we propose a model of neutrino masses and mixing with nonzero $\theta_{13}$ and necessarily large leptonic CP violation, allowing both the normal and inverted hierarchies of neutrino masses, as well as quasi-degenerate solutions.Comment: 12 pages, 12 figure

Radiative Scaling Neutrino Mass with A4A_4 Symmetry

A new idea for neutrino mass was proposed recently, where its smallness is not due to the seesaw mechanism, i.e. not inversely proportional to some large mass scale. It comes from a one-loop mechanism with dark matter in the loop consisting of singlet Majorana fermions $N_i$ with masses of order 10 keV and neutrino masses are scaled down from them by factors of about $10^{-5}$. We discuss how this model may be implemented with the non-Abelian discrete symmetry $A_4$ for neutrino mixing, and consider the phenomenology of $N_i$ as well as the extra scalar doublet $(\eta^+,\eta^0)$.Comment: 11 pages, 1 figur

DNA folding and melting observed in real time redefine the energy landscape

We report real-time observations of the folding and melting of DNA by probing two active sites of a hairpin structure, the bases and the stem end, and using an ultrafast T-jump. Studies at different initial temperatures (before, during, and after melting) provide the time scale of water heating (<20 ps), single-strand destacking (700 ps to 2 ns), and hairpin destacking (microseconds and longer) in solutions of various ionic strengths and pH values. The behavior of transient changes gives direct evidence to the existence of intermediate collapsed structures, labile in destacking but compact in nature, and indicates that melting is not a two-state process. We propose a landscape that is defined by these nucleation structures and destacking for efficient folding and melting

Neutral SU(2) Gauge Extension of the Standard Model and a Vector-Boson Dark-Matter Candidate

If the standard model of particle interactions is extended to include a neutral SU(2)_N gauge factor, with SU(3)_C x SU(2)_L x U(1)_Y x SU(2)_N embedded in E_6 or [SU(3)]^3, a conserved generalized R parity may appear. As a result, we have the first example of a possible dark-matter candidate X_1 which is a non-Abelain vector boson. Using current data, its mass is predicted to be less than about 1 TeV. The associated Z' of this model, as well as some signatures of the Higgs sector, should then be observable at the LHC (Large Hadron Collider).Comment: 10 pages, 1 figure; version accepted in PL

Development and performance determination of warm mix asphalt using rap for Malaysian conditions / Frag Ahmed Ma Kridan

Current concerns on the scarcity of resources necessitate the road building industry to review its production of asphaltic concrete. The use of Warm Mix Asphalt (WMA) technologies with asphalt mixtures containing reclaimed asphalt pavement (RAP) may provide synergistic advantages. WMA-RAP mixes conserves scarce resources such as aggregates by using RAP as partial replacement of aggregates and reduces the use of energy (reduction in production temperature) by using WMA additives. Most specifications allow not more than 30% RAP as higher percentages of RAP introduces variability in the material properties and produces inconsistencies in asphalt mix properties. The goal of this study was to evaluate the performance of warm mix asphalt with high proportions of RAP (30%, 40% and 50%) and using Sasobit as the warm mix additive to reduce the mixing and compaction temperature

Distributed Efficient Similarity Search Mechanism in Wireless Sensor Networks

The Wireless Sensor Network similarity search problem has received considerable research attention due to sensor hardware imprecision and environmental parameter variations. Most of the state-of-the-art distributed data centric storage (DCS) schemes lack optimization for similarity queries of events. In this paper, a DCS scheme with metric based similarity searching (DCSMSS) is proposed. DCSMSS takes motivation from vector distance index, called iDistance, in order to transform the issue of similarity searching into the problem of an interval search in one dimension. In addition, a sector based distance routing algorithm is used to efficiently route messages. Extensive simulation results reveal that DCSMSS is highly efficient and significantly outperforms previous approaches in processing similarity search queries

Towards a unified framework for modeling fault zone evolution: From particles comminution to secondary faults branching

The brittle portion of the crust contains structural features such as faults, jogs, joints, bends, and cataclastic zones that span a wide range of length scales. These features may have a profound effect on earthquake nucleation, propagation, and arrest. Incorporating these existing features in modeling and the ability to spontaneously generate new one in response to earthquake loading is crucial for predicting seismicity patterns, distribution of aftershocks and nucleation sites, earthquakes arrest mechanisms, and topological changes in the seismogenic zone structure. Here, we report on our efforts in modeling two important mechanisms contributing to the evolution of fault zone topology: (i) Grain comminution at the submeter scale, and (ii) Secondary faults generation at the scale of few to hundreds of meters. We model grain comminution within the framework of Shear Transformation Zone theory, a nonequilibrium statistical thermodynamic framework for modeling plastic deformation in amorphous materials. We postulate, based on energy balance, an equation for the grain size reduction as a function of the applied work rate and pressure. We show that grain breakage is a potential weakening mechanism at high strain rate. It promotes strain localization and may explain the long-term persistence of shear bands in natural faults. To model secondary faults generation we developed a nested fault scheme using the finite element software PyLith. As the dynamic rupture propagates on the main fault the stress state changes and eventually the off-fault shear stress is high enough to overcome the pressure-dependent rock strength defined by the Mohr–Coulomb failure envelope. If the Mohr–Coulomb failure criterion is satisfied, a new secondary fault is generated. The angle of the secondary fault with respect to the main fault is taken to be equal to the angle of the critical shear plane. This procedure is repeated until there is no need to add new faults (i.e., stresses everywhere are below the failure threshold). The secondary faults relax the medium contributing to slip and energy partitioning. They also lead to wave diffraction, slip heterogeneity, and slowing down of the rupture on the main fault. They provide potential nucleation site for future ruptures promoting complexity in earthquake cycle simulation. Under repeated earthquake ruptures, regions in the vicinity of primary slip surfaces become heavily fragmented. These regions are modeled using STZ theory. Incorporating the microscale granular model within the macroscopic finite element simulation provide a physics-based multiscale description for damage accumulation. The model provides insight into the dynamic evolution of fault zone topology coupled within the different phases of the seismic cycle. This is crucial for better evaluation of seismic hazard and risk