Low-power scan design using first-level supply gating

Reduction in test power is important to improve battery lifetime in portable electronic devices employing periodic self-test, to increase reliability of testing, and to reduce test cost. In scan-based testing, a significant fraction of total test power is dissipated in the combinational block. In this paper, we present a novel circuit technique to virtually eliminate test power dissipation in combinational logic by masking signal transitions at the logic inputs during scan shifting. We implement the masking effect by inserting an extra supply gating transistor in the supply to ground path for the first-level gates at the outputs of the scan flip-flops. The supply gating transistor is turned off in the scan-in mode, essentially gating the supply. Adding an extra transistor in only one logic level renders significant advantages with respect to area, delay, and power overhead compared to existing methods, which use gating logic at the output of scan flip-flops. Moreover, the proposed gating technique allows a reduction in leakage power by input vector control during scan shifting. Simulation results on ISCAS89 benchmarks show an average improvement of 62% in area overhead, 101% in power overhead (in normal mode), and 94% in delay overhead, compared to the lowest cost existing method.     

Computing with subthreshold leakage: device/circuit/architecture co-design for ultralow-power subthreshold operation

This paper presents a novel design methodology for ultralow-power design using subthreshold leakage as the operating current (suitable for medium frequency of operation: tens to hundreds of millihertz). Standard design techniques suitable for super-threshold design can be used in the subthreshold region. However, in this study, it has been shown that a complete co-design at all levels of hierarchy (device, circuit, and architecture) is necessary to reduce the overall power consumption while achieving acceptable performance (hundreds of millihertz) in the subthreshold regime of operation. Simulation results of co-design on a five-tap finite-impulse-response filter shows /spl sim/2.5/spl times/ improvement in throughput at iso-power compared to a conventional design.     

Significant Enhancement of Proton Transport in Bioinspired Peptide Fibrils by Single Acidic or Basic Amino Acid Mutation

Bioinspired materials are extremely suitable for the development of biocompatible and environmentally friendly functional materials. Peptide‐based assemblies are remarkably attractive for such tasks, since they provide a simple way to fuse together functional and structural protein motifs in artificial materials. Motivated by this idea, it is shown here that the introduction of a single acidic, or basic, amino acid into the side chain of a heptameric self‐assembling peptide increases proton conduction in the resulting fibers by two orders of magnitude. This self‐doping effect is much more pronounced than the effect induced by the peptide's acidic and basic termini groups. Furthermore, the self‐doping process is found to be significantly more effective for acidic side chains than for basic ones due to both much more effective self‐doping process, resulting in an order of magnitude larger concentration of charge carriers for the acidic assemblies, and higher mobility of the formed charge carriers – almost threefolds in this case. This work facilitates the realization of unique bioinspired self‐assembled proton conducting materials that may find uses in the emerging bioprotonic technology. The presented design flexibility and, in particular, the ability to introduce both proton and proton holes further extend the usefulness of these materials.     

Novel Direct Nanopatterning Approach to Fabricate Periodically Nanostructured Perovskite for Optoelectronic Applications

While indirectly patterned organic–inorganic hybrid perovskite nanostructures have been extensively studied for use in perovskite optoelectronic devices, it is still challenging to directly pattern perovskite thin films because perovskite is very sensitive to polar solvents and high‐temperature environments. Here, a simple and low‐cost approach is proposed to directly pattern perovskite solid‐state films into periodic nanostructures. The approach is basically perovskite recrystallization through phase transformation with the presence of a periodic mold on an as‐prepared solid‐state perovskite film. Interestingly, this study simultaneously achieves not only periodically patterned perovskite nanostructures but also better crystallized perovskites and improved optical properties, as compared to its thin film counterpart. The improved optical properties can be attributed to the light extraction and increased spontaneous emission rate of perovskite gratings. By fabricating light‐emitting diodes using the periodic perovskite nanostructure as the emission layers, approximately twofold higher radiance and lower threshold than the reference planar devices are achieved. This work opens up a new and simple way to fabricate highly crystalline and large‐area perovskite periodic nanostructures for low‐cost production of high‐performance optoelectronic devices.     

Convergence properties and stationary points of a perceptronlearning algorithm

An analysis of the stationary (convergence) points of an adaptive algorithm that adjusts the perceptron weights is presented. This algorithm is identical in form to the least-mean-square (LMS) algorithm, except that a hard limiter is incorporated at the output of the summer. The algorithm is described in detail, a simple two-input example is presented, and some of its convergence properties are illustrated. When the input of the perceptron is a Gaussian random vector, the stationary points of the algorithm are not unique and they depend on the algorithm step size and the momentum constant. The stationary points of the algorithm are presented, and the properties of the adaptive weight vector near convergence are discussed. Computer simulations that verify the analysis are given     

Iris segmentation using game theory

Robust segmentation of an iris image plays an important role in iris recognition. However, the nonlinear deformations, pupil dilations, head rotations, motion blurs, reflections, nonuniform intensities, low image contrast, camera angles and diffusions, and presence of eyelids and eyelashes often hamper the conventional iris/pupil localization methods, which utilize the region-based or the gradient-based boundary-finding information. The novelty of this research effort is that we describe a new iris segmentation scheme using game theory to elicit iris/pupil boundaries from a nonideal iris image. We apply a parallel game-theoretic decision making procedure by modifying Chakraborty and Duncan??s algorithm, which integrates (1) the region-based segmentation and gradient-based boundary-finding methods and (2) fuses the complementary strengths of each of these individual methods. This integrated scheme forms a unified approach, which is robust to noise and poor localization, and less affected by weak iris/sclera boundaries. The verification and identification performance of the proposed method are validated using the ICE 2005, the UBIRIS Version 1, WVU Nonideal, and the CASIA Version 3 data sets.     

Design and investigations on a compact,UWB, monopole antenna with reconfigurable band notches for 5.2/5.8 GHz WLAN and 5.5 GHz Wi‐MAX bands

This article represents a microstrip line–fed novel circular monopole antenna with ultra‐wideband (UWB) characteristics. The compact antenna provides reconfigurable notches at WLAN (5.2/5.8 GHz) and Wi‐MAX (5.5 GHz) frequency bands. The band rejection is achieved by etching an open‐ended L‐shaped slot in the ground plane, which effectively mitigates the interference between WLAN, Wi‐MAX, and UWB systems with an effective patch area of 36.26%. The proposed antenna operates from 3.05 to 12.11 GHz with VSWR 2 except at stopband (3.89‐5.93 GHz) to filter the WLAN and Wi‐MAX signals. The simulated return loss, gain, and radiation pattern of the proposed antenna has been experimentally verified with the fabricated one which holds a good agreement.     

Mimicking Neuroplasticity in a Hybrid Biopolymer Transistor by Dual Modes Modulation

Neuromorphic computing systems that are capable of parallel information storage and processing with high area and energy efficiencies, offer important opportunities for future storage systems and in‐memory computing. Here, it is shown that a carbon dots/silk protein (CDs/silk) blend can be used as a light‐tunable charge trapping medium to fabricate an electro‐photoactive transistor synapse. The synaptic device can be optically operated in volatile or nonvolatile modes, ensuring concomitant short‐term and long‐term neuroplasticity. The synaptic‐like behaviors are attributed to the photogating effect induced by trapped photogenerated electrons in the hybrid CDs/silk film which is confirmed with atomic force microscopy based electrical techniques. In addition, system‐level pattern recognition capability of the synaptic device is evaluated by a single‐layer perceptron model. The remote optical operation of neuromorphic architecture provides promising building blocks to complete bioinspired photonic computing paradigms.     

Effects of feeding an aquatic weed Lemna trisulaca as partial replacement of fish meal on the performance of growing ducklings

Growing ducklings were fed diets containing an aquatic weed Lemna trisulaca meal (LTM) replacing, on a protein basis, either 40, 60 or 80 g kg^?1 of the fish meal (FM) from a control diet which contained 120 g FM kg^?1. Partial replacement of FM (40 and 60 g kg^?1 of the FM) by LTM on a protein basis showed good growth and low food consumption but food conversion efficiency was found to be comparable. It was concluded that LTM could be considered as a protein feed supplement for growing ducklings and also as a part replacement of animal protein (FM) in the nutrition of growing ducklings without deleterious effect on performance.     

Design of AM-TCM schemes for the impulse noise environment

Channel coding for an impulse noise environment modeled as a Cauchy-Gaussian mixture is addressed. Code design based on the pairwise probability of error indicates the suitability of Hamming distance as a primary determinant of performance. Simulation results of code performance for the maximum likelihood (ML) and several suboptimal metrics are presented