Predictive models for multibiometric systems

Recognizing a subject given a set of biometrics is a fundamental pattern recognition problem. This paper builds novel statistical models for multibiometric systems using geometric and multinomial distributions. These models are generic as they are only based on the similarity scores produced by a recognition system. They predict the bounds on the range of indices within which a test subject is likely to be present in a sorted set of similarity scores. These bounds are then used in the multibiometric recognition system to predict a smaller subset of subjects from the database as probable candidates for a given test subject. Experimental results show that the proposed models enhance the recognition rate beyond the underlying matching algorithms for multiple face views, fingerprints, palm prints, irises and their combinations.     

Temperature responsive fibers with anisotropic transitional behavior

Temperature sensitive polymer hydrogels are being extensively studied because of their potential applications in the biomedical, robotics, and chemical industries. However, major hurdles in their development have been their slow response, low efficiency (swelling/deswelling ratios), and poor mechanical properties due to difficulty in processing them into mechanically strong and fine structures. Fibers made from such polymers would be highly desirable. A temperature sensitive random linear copolymer of N‐tert‐butylacrylamide (NTBA) and acrylamide (Am) was synthesized by the solution polymerization method, using regulated dosing of comonomers. Using a novel approach, a high molecular weight poly(N‐tert‐butylacrylamide‐ran‐acrylamide::27 : 73) has been converted to insoluble strong fibers with fineness of 30–50 microns by solution spinning, drawing, and subsequent crosslinking. Fibers were solution spun in acetone using a 14% copolymer solution in acetic acid with polycarboxylic acid as a crosslinker and sodium hypophosphite as a catalyst. The crosslinks were formed, subsequent to drawing, between reactive amide side groups of the acrylamide moiety of the polymer and the carboxylic acid group of the crosslinker by thermal treatment at 160°C. The transition temperatures of the crosslinked fibers were found to shift towards the lower temperature from 37°C (in linear copolymer) to 22–25°C. These engineered fibers display sharp temperature sensitivity, extremely high reversible change in dimensions (1000% in diameter and ～ 70% in length), and extremely fast response time (< 20 s for expansion and < 2 s for contraction). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 681–688, 2005     

Newer intermediates for plastics and coatings. III. Polyesters based on methylene-di-β-oxynaphthoic acid

A tetrafunctional dibasic acid, methylene-di-β-oxynaphthoic acid (MDNA), has been used for preparation of unsaturated polyester resins. The films obtained from these products have excellent chemical and physical properties comparable to epoxy resins and to a large extent balance some of their shortcomings such as darker color, higher viscosities, and higher cooking temperatures. The possible applications of these resins are coatings where acid, corrosion, and thermal resistance are of primary importance.     

BEES: exploring Mars with bioinspired technologies

The bioinspired engineering of exploration systems (BEES) applies insects' biological sensory and flight control abilities to the design of real-time autonomous, visual-navigation and control systems for small unmanned flying vehicles. The bioinspired engineering of exploration systems focuses on using the variety of nature-tested mechanisms successfully implemented by biological organisms but not easily accomplished by conventional methods. We apply BEES technology to the development of bioinspired visual navigation sensors integrated on small flyers to enable autonomous flight. BEES technology extracts the salient principles from a variety of diverse organisms adept at flight, and applies them to machines that can fly on Mars.     

Ba-M+Y (Ba4−XCo2+XFe36O60) complex hexaferrite: structural,electrical, magnetic,and enhanced microwave absorbing properties over 8–18 GHz frequency

Journal of Materials Science: Materials in Electronics - Hexaferrites are a class of materials that have practical applications as microwave absorbing materials (MAMs) and radar absorbing materials...     

Learning small gallery size for prediction of recognition performance on large populations

This paper addresses the estimation of a small gallery size that can generate the optimal error estimate and its confidence on a large population (relative to the size of the gallery) which is one of the fundamental problems encountered in performance prediction for object recognition. It uses a generalized two-dimensional prediction model that combines a hypergeometric probability distribution model with a binomial model and also considers the data distortion problem in large populations. Learning is incorporated in the prediction process in order to find the optimal small gallery size and to improve the prediction. The Chernoff and Chebychev inequalities are used as a guide to obtain the small gallery size. During the prediction, the expectation–maximization (EM) algorithm is used to learn the match score and the non-match score distributions that are represented as a mixture of Gaussians. The optimal size of the small gallery is learned by comparing it with the sizes obtained by the statistical approaches and at the same time the upper and lower bounds for the prediction on large populations are obtained. Results for the prediction are presented for the NIST-4 fingerprint database.     

Simulation and overall comparative evaluation of performance between different techniques for high band feature extraction based on artificial bandwidth extension of speech over proposed global system for mobile full rate narrow band coder

This paper addresses a novel approach to investigate, study and simulate computation of high band (HB) feature extraction based on linear predictive coding (LPC) and mel frequency cepstral coefficient (MFCC) techniques. Further, HB features are embedded into encoded bitstream of proposed global system for mobile (GSM) full rate (FR) 06.10 coder using joint source coding and data hiding before being transmitted to receiving terminal. At receiver, HB features are extracted to reproduce HB portion of speech and for the same different extension of excitation techniques are applied and their results evaluated in terms of quality (intelligibility and naturalness) and bandwidth. MATLAB based e-test bench is created for implementing the proposed artificial bandwidth extension (ABE) coder following series of simulations, that are carried out to discover and gain insight about the performance of it using subjective [mean opinion score (MOS)] and objective [perceptual evaluation of speech quality (PESQ)] analysis. The results obtained for both the analyses advocate that proposed ABE coder outperforms proposed GSM FR NB (legacy GSM FR) coder. While the fact remains that, compared to LPC based parameterizations over ABE coder, MFCC parameterization results in higher speech intelligibility which is evident from obtained slightly better PESQ and MOS scores.     

Proposed modifications in ETSI GSM 06.10 full rate speech codec and its overall evaluation of performance using MATLAB

Today, the primary constrain in wireless communication system is limited bandwidth and power. Wireless systems involved in transmission of speech envisage that efficient and effective methods be developed (bandwidth usage & power) to transmit and receive the same while maintaining quality-of-speech, especially at the receiving end. Speech coding is a technique, since the era of digitization (digital) and computerization (computational and processing horsepower—DSP) that has been a material-of-research for quite some time amongst the scientific and academic community. Amongst all elements of the communication system (transmitter, channel and receiver), transmission channel (carrier of information/data, also called the medium) is the most critical and plays a key role in the transmission and reception of information/data.     

Influence of Co<Superscript>++</Superscript> ion concentration on magnetic and microwave properties of Ba<Subscript>(4−X)</Subscript>Co<Subscript>(2+X)</Subscript>Fe<Subscript>36</Subscript>O<Subscript>60</Subscript> (Ba-M-Y) hexaferrite

The present paper reports the influence of cobalt content on the structural, electrical, magnetic and microwave properties of barium hexaferrite synthesized via chemical co-precipitation method. The samples were characterized for their structural, electrical, magnetic and microwave characterizations using XRD, SEM, TEM, VSM etc. The transmission electron microscopy results showed that stacking of nanoparticles of size?~?50 nm. In addition, the highest saturation magnetization of 29.82 emu/g was observed for composition x?=?0.2. The microwave permittivity and permeability decreases with frequency and it varies with the cobalt concentration. Cobalt concentration strongly affects the microwave and magnetic properties of hexaferrite.     

Optically addressed ferroelectric memory and its applications

Abstract

Thin films of perovskite titanates can be composition-tailored to exhibit ferroelectric, pyroelectric, or piezoelectric properties, in varying degree of combinations, and thereby modulating their response when illuminated with light. This paper reviews the potential applications of photoresponse from lead zirconate titanate thin films. In ferroelectric materials, such as lead zirconate titanate (PZT), for example, the photoresponse shows a clear dependence on remanent polarization. The main highlight of the paper is a review of the concept of optically addressed ferroelectric memory and identification of its high impact applications. Incidence of energetic laser beam pulses gives rise to two different classes of phenomena: first, a thermally triggered piezoelectric/pyroelectric response and second, an optoelectronic response. Optimizing the device geometry and selecting the illumination characteristics, one can easily control the dominating mechanism in a device. The optoelectronic effect emerges at a relatively lower incident beam power (≤2 mW/μm²) and can be as fast as the duration of the pulse (≤10ns), and therefore, is directly relevant as a non-destructive read-out signal from optically addressed ferroelectric memory. The optical NDRO signal offers itself as a unique tool that allows a non-destructive ‘probe’ for the capacitor, without causing any polarization switching in it, the characteristic artifact of the electrical destructive readout (DRO) measurement technique. Furthermore, the polarization dependent photoresponse could also be exploited as a non-destructive evaluation tool for mapping the domains in ferroelectric films, to generate fundamental understanding of the domain dynamics (generation, growth, movement, etc., under applied field, illumination, and/or temperature) in such thin films. In addition, with a high fidelity analog nature of the remanent polarization, the highly parallel, high speed photoresponse output from such optically addressed memories may be ideally suited for high performance computing applications especially involving image processing, high speed communication and parallel processing with architectures, such as large scale artificial neural networks.