A M\"untz-Collocation spectral method for weakly singular volterra integral equations

In this paper we propose and analyze a fractional Jacobi-collocation spectral method for the second kind Volterra integral equations (VIEs) with weakly singular kernel $(x-s)^{-\mu},0<\mu<1$. First we develop a family of fractional Jacobi polynomials, along with basic approximation results for some weighted projection and interpolation operators defined in suitable weighted Sobolev spaces. Then we construct an efficient fractional Jacobi-collocation spectral method for the VIEs using the zeros of the new developed fractional Jacobi polynomial. A detailed convergence analysis is carried out to derive error estimates of the numerical solution in both $L^{\infty}$- and weighted $L^{2}$-norms. The main novelty of the paper is that the proposed method is highly efficient for typical solutions that VIEs usually possess. Precisely, it is proved that the exponential convergence rate can be achieved for solutions which are smooth after the variable change $x\rightarrow x^{1/\lambda}$ for a suitable real number $\lambda$. Finally a series of numerical examples are presented to demonstrate the efficiency of the method

Interaction of magnetic resonators studied by the magnetic field enhancement

It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs

Coherence of magnetic resonators in a metamaterial

The coherence of periodic magnetic resonators (MRs) under oblique incidence is studied using simulations. The correlated phase of interaction including both the retardation effect and relative phase difference between two MRs is defined, and it plays a key role in the MR interaction. The correlated phase is anisotropic, as is the coherence condition. The coherence condition is the same as the Wood's anomaly and verified by the Fano resonance. This study shows that the applications of the Fano resonance of periodic MRs will become widespread owing to achieving the Fano resonance simply by tuning the incident angle

A Processing-in-Memory Architecture Programming Paradigm for Wireless Internet-of-Things Applications

The widespread applications of the wireless Internet of Things (IoT) is one of the leading factors in the emerging of Big Data. Huge amounts of data need to be transferred and processed. The bandwidth and latency of data transfers have posed a new challenge for traditional computing systems. Under Big Data application scenarios, the movement of large scales of data would influence performance, power efficiency, and reliability, which are the three fundamental attributes of a computing system. Thus, changes in the computing paradigm are demanding. Processing-in- Memory (PIM), aiming at placing computation as close as possible to memory, has become of great interest to academia as well as industries. In this work, we propose a programming paradigm for PIM architecture that is suitable for wireless IoT applications. A data-transferring mechanism and middleware architecture are presented. We present our methods and experiences on simulation-platform design, as well as FPGA demo design, for PIM architecture. Typical applications in IoT, such as multimedia and MapReduce programs, are used as demonstration of our method&rsquo;s validity and efficiency. The programs could successfully run on the simulation platform built based on Gem5 and on the FPGA demo. Results show that our method could largely reduce power consumption and execution time for those programs, which is very beneficial in IoT applications

CDSP: A Solution for Privacy and Security of Multimedia Information Processing in Industrial Big Data and Internet of Things

With the widespread nature of wireless internet and internet of things, data have bloomed everywhere. Under the scenario of big data processing, privacy and security concerns become a very important consideration. This work focused on an approach to tackle the privacy and security issue of multimedia data/information in the internet of things domain. A solution based on Cryptographical Digital Signal Processor (CDSP), a Digital Signal Processor (DSP) based platform combined with dedicated instruction extension, has been proposed, to provide both programming flexibility and performance. We have evaluated CDSP, and the results show that the algorithms implemented on CDSP all have good performance. We have also taped out the platform designed for privacy and security concerns of multimedia transferring system based on CDSP. Using TSMC 55 nm technology, it could reach the speed of 360 MHz. Benefiting from its programmability, CDSP can be easily expanded to support more algorithms in this domain

Microstructure and compressive behavior of lamellar Al2O3p/Al composite prepared by freeze-drying and mechanical-pressure infiltration method

Infiltrated molten Al matrix by mechanical-pressure infiltration method into the ceramic scaffold prepared by freeze-drying technology could prepare dense lamellar Al matrix composites without damage of the biomimetic microstructure of the scaffold. However, the investigation of lamellar Al matrix composites prepared by freeze-drying and mechanical-pressure infiltration method has not been fully understood yet. In the present work, the Al2O3 scaffold with pearl layer structure was prepared by freezing-dry method, and eventually the lamellar Al2O3p/Al composite was fabricated by mechanical-pressure infiltration method. The Al matrix was infiltrated well into the large pores of the Al2O3 scaffold, and the lamellar structure of the Al2O3 was well preserved. The hardness of the lamellar Al2O3p/Al composite was isotropic in transvers and perpendicular directions. However, the compressive strengths of the lamellar Al2O3p/Al composite were significant anisotropic while the compressive strength in transvers direction was 127.7% higher than that in the perpendicular direction, indicating the integrality of the lamellae microstructure (especially the bridging layers). Due to the mismatched deformability, weak debonding was observed between Al and Al2O3p/Al layers in the fracture surface of the lamellar Al2O3p/Al composite. It indicates that the interfacial bonding between Al and Al2O3p/Al layers is rather strong, which is beneficial for higher strength in transvers direction but lead to lower strength in perpendicular direction