Localization of Surface Plasmon Polaritons in Hexagonal Arrays of Moire Cavities

Cataloged from PDF version of article.In view of the progress on the confinement of light, we report on the dispersion characteristics of surface plasmon polaritons (SPPs) on two-dimensional Moire surfaces in the visible part of the electromagnetic spectrum. Polarization dependent spectroscopic reflection measurements show omnidirectional confinement of SPPs. The resonance wavelength of SPP cavity modes can be adjusted by tuning the propagation direction of SPPs. The results may have an impact on the control of spontaneous emission and absorption with applications in light emitting diodes and solar cells, as well as in quantum electrodynamics experiments. (C) 2011 American Institute of Physics. [doi:10.1063/1.3529469

VIBE: Video Inference for Human Body Pose and Shape Estimation

Human motion is fundamental to understanding behavior. Despite progress on single-image 3D pose and shape estimation, existing video-based state-of-the-art methods fail to produce accurate and natural motion sequences due to a lack of ground-truth 3D motion data for training. To address this problem, we propose Video Inference for Body Pose and Shape Estimation (VIBE), which makes use of an existing large-scale motion capture dataset (AMASS) together with unpaired, in-the-wild, 2D keypoint annotations. Our key novelty is an adversarial learning framework that leverages AMASS to discriminate between real human motions and those produced by our temporal pose and shape regression networks. We define a temporal network architecture and show that adversarial training, at the sequence level, produces kinematically plausible motion sequences without in-the-wild ground-truth 3D labels. We perform extensive experimentation to analyze the importance of motion and demonstrate the effectiveness of VIBE on challenging 3D pose estimation datasets, achieving state-of-the-art performance. Code and pretrained models are available at https://github.com/mkocabas/VIBE.Comment: CVPR-2020 camera ready. Code is available at https://github.com/mkocabas/VIB

Enhancing an Embedded Processor Core with a Cryptographic Unit for Performance and Security

We present a set of low-cost architectural enhancements to accelerate the execution of certain arithmetic operations common in cryptographic applications on an extensible embedded processor core. The proposed enhancements are generic in the sense that they can be beneficially applied in almost any RISC processor. We implemented the enhancements in form of a cryptographic unit (CU) that offers the programmer an extended instruction set. The CU features a 128-bit wide register file and datapath, which enables it to process 128-bit words and perform 128-bit loads/stores. We analyze the speed-up factors for some arithmetic operations and public-key cryptographic algorithms obtained through these enhancements. In addition, we evaluate the hardware overhead (i.e. silicon area) of integrating the CU into an embedded RISC processor. Our experimental results show that the proposed architectural enhancements allow for a significant performance gain for both RSA and ECC at the expense of an acceptable increase in silicon area. We also demonstrate that the proposed enhancements facilitate the protection of cryptographic algorithms against certain types of side-channel attacks and present an AES implementation hardened against cache-based attacks as a case study

An elastomeric grating coupler

We report on a novel nondestructive and reversible method for coupling free space light to planar optical waveguides. In this method, an elastomeric grating is used to produce an effective refractive index modulation on the surface of the optical waveguide. The external elastomeric grating binds to the surface of the waveguide with van der Waals forces and makes conformal contact without any applied pressure. As a demonstration of the feasibility of the approach, we use it to measure the refractive index of a silicon oxynitride film. This technique is nondestructive, reversible, low cost and can easily be applied to the characterization of optical materials for integrated optics

Slowing surface plasmon polaritons on plasmonic coupled cavities by tuning grating grooves

Cataloged from PDF version of article.We investigate slow surface plasmon polaritons (SPPs) in plasmonic waveguiding bands formed by coupled plasmonic cavities on Moire surfaces. We demonstrate controlling the group velocity and dispersion of the SPPs by varying the depth of the plasmonic Bragg grating groove. Changing the grating depth results in modification of coupling coefficients between the cavities and hence the SPPs group velocity is altered. Variation in the group velocity and dispersion of SPPs can be measured with polarization dependent spectroscopic reflection measurements. Dispersion of SPPs has been calculated by finite-difference time-domain method in agreement with the experimental data. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3495781

Efficient Radiometric Signature Methods for Cognitive Radio Devices

This thesis presents the first comprehensive study and new methods for radiometric fingerprinting of the Cognitive Radio (CR) devices. The scope of the currently available radio identification techniques is limited to a single radio adjustment. Yet, the variable nature of the CR with multiple levels of parameters and adjustments renders the radiometric fingerprinting much more complex. We introduce a new method for radiometric fingerprinting that detects the unique variations in the hardware of the reconfigurable radio by passively monitoring the radio packets. Several individual identifiers are used for extracting the unique physical characteristics of the radio, including the frequency offset, modulated phase offset, in-phase/quadrature-phase offset from the origin, and magnitude. Our method provides stable and robust identification by developing individual identifiers (classifiers) that may each be weak (i.e., incurring a high prediction error) but their committee can provide a strong classification technique. Weighted voting method is used for combining the classifiers. Our hardware implementation and experimental evaluations over multiple radios demonstrate that our weighted voting approach can identify the radios with an average of 97.7% detection probability and an average of 2.3% probability of false alarm after testing only 5 frames. The probability of detection and probability of false alarms both rapidly improve by increasing the number of test frames

Atypical P-type ATPases, CtpE and CtpF from Mycobacteria tuberculosis

Mycobacterium tuberculosis causes tuberculosis, one of the most life-threatening diseases of all time. It infects the host macrophages and survives in its phagosome. The host phagosome is a very hostile environment where M. tuberculosis copes with high concentration of transition metals (Zn2+, Cu2+), low levels of others (Mn2+, Fe2+) and acidic pH. P-ATPases are membrane proteins that transport various ions against their electrochemical gradients utilizing the energy of ATP hydrolysis. Based on their primary sequences; seven of the twelve mycobacterial ATPases are classified as putative heavy metal transporters and a K+-ATPase, while the substrate of four (CtpE, CtpF, CtpH and CtpI) remains unknown. Consistent with their membrane topology and conserved amino acids, CtpE and CtpF are possibly P2 or P3-ATPases that transport alkali metals or protons. We examined the cellular roles of orthologous CtpE and CtpF in M. smegmatis, a non-pathogenic model organism. We hypothesized that these novel P- ATPases play an important role in transporting alkali metals and/or protons. We analyzed growth fitness of strains carrying mutations of the coding gens of these enzymes, in presence of various metals and different pHs, as well as the gene expression levels under different stress conditions. We observed that the M. smegmatis mutant strains, lacking of CtpF or CtpE, are sensitive to high concentrations (mM) of Mn2+. Furthermore, CtpE mutant is sensitive to alkali pH. Our results indicate that CtpE and CtpF might be an Mn2+ or H+-ATPase that are required for cell’s homeostasis sustainability

VILLAGE INSTITUTES IN TURKEY AND COOPERATIVE LEARNING

The aims of Village Institutes were to create modern Turkey and start development from the villages by presenting civilization and revolutions to Turkish villagers and to supply primary education in the villages at 100% percent. In 17 April 1940, “Village Institutes” were founded by Ministry of National Education Hasan Ali Yücel and his General Director of Primary Education İsmail Hakkı Tonguç. The most important principles of them were; education in work, education with work, education for work. The Village Institutes’ system allowed the students to participate actively into education with their own actions leading to educated, critical thinking and creative individuals being capable of using their rights in the right manner; moreover, leading the formation of a creative society. In this article, similar and common dimensions of the group works applied in the Village Institutes and Cooperative Learning have been presented. Also, being aware of this educational system in Turkey in the past is tried to be provided. As a result, the value of The Village Institutes’ system should be regiven to humanity by using its positive aspects in today’s education systems.  Article visualizations

Synthesis of titanium dioxide nanoparticles and their application for simultaneous photocatalytic oxidation of As(III) and sorption of As(V)

In this study, the effectiveness of TiO2 nanoparticles in removing arsenic species from water was enhanced by the photocatalytic oxidation by conversion of As(III) to As(V), which adsorbs more strongly onto the solid phase of adsorbent than As(III). Anatase nanoparticles were synthesized by using sol-gel method and the synthesized nanoparticles were characterized by X-ray diffraction and scanning electron microscopy. Batch adsorption experiment was carried out to analyze As(III) removal capacity of the anatase nanoparticles with and without presence of photocatalytic oxidation reaction. The maximum % of removal of As(III) was found ~56% at pH 6, respectively, when 1 g l-1 anatase nanoparticles were used at the As0 1 ppm without presence of photocatalytic oxidation reaction. In contrast, over 94.7% As(V) have been removed by anatase nanoparticles in a period of 120 min UV-light irradiation. Using photocatalytic oxidation process, As(III) removal from water was improved by UV-irradiation