Blocking online advertising - a state of the art

Online advertising has emerged as one of the major business models on the Internet. Publishers rely on the online revenue generated from advertising to offer many free services. However it has become evident that online advertisements are now becoming quite intrusive and also consume a lot of valuable bandwidth to download zero-caching ads and flash or video ads. The main contribution of this paper is as follows; it attempts to identify the main reasons why internet users want to block online ads, it also critically evaluates several existing ad-blocking techniques and conducts an experiment to measure the amount of bandwidth used by online advertisements relative to the actual content. Near the end of the paper a brief discussion on probable future researches open a vast new region to be explored

A subalgebra of the Hardy algebra relevant in control theory and its algebraic-analytic properties

We denote by A_0+AP_+ the Banach algebra of all complex-valued functions f defined in the closed right half plane, such that f is the sum of a holomorphic function vanishing at infinity and a ``causal'' almost periodic function. We give a complete description of the maximum ideal space M(A_0+AP_+) of A_0+AP_+. Using this description, we also establish the following results: (1) The corona theorem for A_0+AP_+. (2) M(A_0+AP_+) is contractible (which implies that A_0+AP_+ is a projective free ring). (3) A_0+AP_+ is not a GCD domain. (4) A_0+AP_+ is not a pre-Bezout domain. (5) A_0+AP_+ is not a coherent ring. The study of the above algebraic-anlaytic properties is motivated by applications in the frequency domain approach to linear control theory, where they play an important role in the stabilization problem.Comment: 17 page

Prioritizing Information for Achieving QoS Control in WSN

Achieving QoS objective in Wireless Sensor Network (WSN) that deals with multimedia information is of paramount importance in the WSN research community. From the application point of view, meeting application specific QoS constraints is equally important as designing energy efficient embedded circuitry for WSN nodes. Among various WSN communication protocol stack, the transport layer functionality has gain fundamental fame lately in addressing the application specific QoS objectives by supporting Source prioritization besides the reliability and congestion control aspects of the design that helps in gaining high throughput with minimum end-to-end packet latency. This paper present the design of a new transport layer protocol that prioritizes sensed information based on its nature while simultaneously supporting the data reliability and congestion control features.The proposed transport protocol is tested in three possible scenarios i.e. with priority, without and distributed priority features. Simulation results reveal that by prioritizing the Source information and prioritized intermediate storage and forwarding reduces the End-to-End (E-2-E) latency of Source packets having 400 msec which is quite significant. Simulation test has been performed for distributed prioritized intermediate storage and forwarding among which the network distribution with node K as prioritized intermediate storage node (DIST-K) outperformed all of the mentioned cases by having 100% achieved Source priority,0% packet drop rate and 0.28 Mbps achieved bit rate

Priority Enabled Transport Layer Protocol for Wireless Sensor Network

Achieving Quality of Service (QoS) objective in Wireless Sensor Network (WSN) handling the multimedia information has significantly gained the importance lately besides energy efficient hardware designing. Transport layer of the WSN communication protocol stack plays a significant role in meeting the QoS objective of WSN. This paper presents a light weight transport protocol for WSN that can handle packets from a numbers of sources having different sensed information and having different priority levels. The protocol assigned middle motes are intelligent enough to achieve prioritization in transmission based on the priority level and packet's Time-To-Live (TTL) information. Extensive simulation is carried out for the three different modes of the envisaged protocol having no prioritized enabled storage, complete prioritized enabled storage and distributed prioritized enabled storage. The results reveal that the significant improvement is observed in case of distributed prioritized enabled storage, approximately 3% data loss occurred, in comparison to 7% data loss for without prioritized enabled storage mode

Performance evaluation of different transport layer protocols on the IEEE 802.11 and IEEE 802.15.4 MAC/PHY layers for WSN

Wireless Sensor Networks (WSN) has gathered lot of attention from the research community lately. Among other WSN communication protocols, transport layer protocol plays a significant role in maintaining the node?s energy budget. In this context we have carried out extensive testing of various transport protocols using IEEE 802.11, IEEE 802.15.4 MAC/PHY protocol and Ad hoc On-Demand Distance Vector Routing (AODV) routing agent for WSN having multi-hop ad-hoc and WPAN network topology. The main contribution of this paper is to find out the dependency of Transport layer on MAC layer. Simulation results indicate that the underlying MAC/PHY layer protocol along with Transport layer protocol plays a vital role in achieving the high throughput, low latency and packet loss rate in WSN. For IEEE 802.11 with RTS/CTS ON high throughput, low packet drop rate and increased end-to-end packet delay is observed. While for IEEE 802.15.4 similar behavior as for IEEE 802.11 (except for UDP) but with improved power efficiency is observed. This has led the foundation for the future development of the proposed cross layered energy efficient transport protocol for multimedia application

Extreme mechanical resilience of self-assembled nanolabyrinthine materials

Low-density materials with tailorable properties have attracted attention for decades, yet stiff materials that can resiliently tolerate extreme forces and deformation while being manufactured at large scales have remained a rare find. Designs inspired by nature, such as hierarchical composites and atomic lattice-mimicking architectures, have achieved optimal combinations of mechanical properties but suffer from limited mechanical tunability, limited long-term stability, and low-throughput volumes that stem from limitations in additive manufacturing techniques. Based on natural self-assembly of polymeric emulsions via spinodal decomposition, here we demonstrate a concept for the scalable fabrication of nonperiodic, shell-based ceramic materials with ultralow densities, possessing features on the order of tens of nanometers and sample volumes on the order of cubic centimeters. Guided by simulations of separation processes, we numerically show that the curvature of self-assembled shells can produce close to optimal stiffness scaling with density, and we experimentally demonstrate that a carefully chosen combination of topology, geometry, and base material results in superior mechanical resilience in the architected product. Our approach provides a pathway to harnessing self-assembly methods in the design and scalable fabrication of beyond-periodic and nonbeam-based nano-architected materials with simultaneous directional tunability, high stiffness, and unsurpassed recoverability with marginal deterioration

Predicting Microstructural Pattern Formation Using Stabilized Spectral Homogenization

Instability-induced patterns are ubiquitous in nature, from phase transformations and ferroelectric switching to spinodal decomposition and cellular organization. While the mathematical basis for pattern formation has been well-established, autonomous numerical prediction of complex pattern formation has remained an open challenge. This work aims to simulate realistic pattern evolution in material systems exhibiting non-(quasi)convex energy landscapes. These simulations are performed using fast Fourier spectral techniques, developed for high-resolution numerical homogenization. In a departure from previous efforts, compositions of standard FFT-based spectral techniques with finite-difference schemes are used to overcome ringing artifacts while adding grid-dependent implicit regularization. The resulting spectral homogenization strategies are first validated using benchmark energy minimization examples involving non-convex energy landscapes. The first investigation involves the St. Venant-Kirchhoff model, and is followed by a novel phase transformation model and finally a finite-strain single-slip crystal plasticity model. In all these examples, numerical approximations of energy envelopes, computed through homogenization, are compared to laminate constructions and, where available, analytical quasiconvex hulls. Subsequently, as an extension of single-slip plasticity, a finite-strain viscoplastic formulation for hexagonal-closed-packed magnesium is presented. Microscale intragranular inelastic behavior is captured through high-fidelity simulations, providing insight into the micromechanical deformation and failure mechanisms in magnesium. Studies of numerical homogenization in polycrystals, with varying numbers of grains and textures, are also performed to quantify convergence statistics for the macroscopic viscoplastic response. In order to simulate the kinetics of pattern evolution, stabilized spectral techniques are utilized to solve phase-field equations. As an example of conservative gradient-flow kinetics, phase separation by anisotropic spinodal decomposition is shown to result in cellular structures with tunable elastic properties and promise for metamaterial design. Finally, as an example of nonconservative kinetics, the study of domain wall motion in polycrystalline ferroelectric ceramics predicts electromechanical hysteresis behavior under large bias fields. A first-principles approach using DFT-informed model constants is outlined for lead zirconate titanate, producing results showing convincing qualitative agreement with in-house experiments. Overall, these examples demonstrate the promise of the stabilized spectral scheme in predicting pattern evolution as well as effective homogenized response in systems with non-quasiconvex energy landscapes.</p

Stochastic modeling of discontinuous dynamic recrystallization at finite strains in hcp metals

We present a model that aims to describe the effective, macroscale material response as well as the underlying mesoscale processes during discontinuous dynamic recrystallization under severe plastic deformation. Broadly, the model brings together two well-established but distinct approaches – first, a continuum crystal plasticity and twinning approach to describe complex deformation in the various grains, and second, a discrete Monte-Carlo-Potts approach to describe grain boundary migration and nucleation. The model is implemented within a finite-strain Fast Fourier Transform-based framework that allows for efficient simulations of recrystallization at high spatial resolution, while the grid-based Fourier treatment lends itself naturally to the Monte-Carlo approach. The model is applied to pure magnesium as a representative hexagonal closed packed metal, but is sufficiently general to admit extension to other material systems. Results demonstrate the evolution of the grain architecture in representative volume elements and the associated stress–strain history during the severe simple shear deformation typical of equal channel angular extrusion. We confirm that the recrystallization kinetics converge with increasing grid resolution and that the resulting model captures the experimentally observed transition from single- to multi-peak stress–strain behavior as a function of temperature and rate