Designing Nanoscale Logic Circuits Based on Markov Random Fields

As devices and operating voltages are scaled down, future circuits will be plagued by higher soft error rates, reduced noise margins and defective devices. A key challenge for the future is retaining high reliability in the presence of faulty devices and noise. Probabilistic computing offers one possible approach. In this paper we describe our approach for mapping circuits onto CMOS using principles of probabilistic computation. In particular, we demonstrate how Markov random field elements may be built in CMOS and used to design combinational circuits running at ultra low supply voltages. We show that with our new design strategy, circuits can operate in highly noisy conditions and provide superior noise immunity, at reduced power dissipation. If extended to more complex circuits, our approach could lead to a paradigm shift in computing architecture without abandoning the dominant silicon CMOS technology.     

A 100-MHz macropipelined VAX microprocessor

A macropipelined CISC microprocessor was implemented in a 0.75-μm CMOS 3.3-V technology. The 1.3-million-transistor custom chip measures 1.62×1.46 cm² and dissipates 16.3 W. The 100-MHz parts were benchmarked at 50 SPEC marks. The on-chip clocking system and several high-performance logic and circuit techniques are described. Macroinstruction handling, micropipeline management, and control store structures highlight the design architecture. The hierarchical array organization and fast tag comparison technique of the primary cache are discussed. Power estimation procedures are outlined, and the results are compared to measurements. Physical design and verification methods, and CAD tools are also described. After extensive functional verification efforts are described, chip and system test results are presented     

Exploring network-level performances of wireless nanonetworks utilizing gains of different types of nano-antennas with different materials

Wireless nanonetworks are not a simple extension of traditional communication networks at the nano-scale. Owing to being a completely new communication paradigm, existing research in this field is still at an embryonic stage. Furthermore, most of the existing studies focus on performance enhancement of nanonetworks via designing new channel models and routing protocols. However, the impacts of different types of nano-antennas on the network-level performances of the wireless nanonetworks remain still unexplored in the literature. Therefore, in this paper, we explore the impacts of different well-known types of antennas such as patch, dipole, and loop nano-antennas on the network-level performances of wireless nanonetworks. We also investigate the performances of nanonetworks for different types of traditional materials (e.g., copper) and for nanomaterials (e.g., carbon nanotubes and graphene). We perform rigorous simulation using our customized ns-2 simulation to evaluate the network-level performances of nanonetworks exploiting different types of nano-antennas using different materials. Our evaluation reveals a number of novel findings pertinent to finding an efficient nano-antenna from its several alternatives for enhancing network-level performances of nanonetworks. Our evaluation demonstrates that a dipole nano-antenna using copper material exhibits around 51% better throughput and about 33% better end-to-end delay compared to other alternatives for large-size nanonetworks. Furthermore, our results are expected to exhibit high impacts on the future design of wireless nanonetworks through facilitating the process of finding the suitable type of nano-antenna and suitable material for the nano-antennas.

     

Spectral estimation of nonstationary EEG using particle filtering with application to event-related desynchronization (ERD)

This paper proposes non-Gaussian models for parametric spectral estimation with application to event-related desynchronization (ERD) estimation of nonstationary EEG. Existing approaches for time-varying spectral estimation use time-varying autoregressive (TVAR) state-space models with Gaussian state noise. The parameter estimation is solved by a conventional Kalman filtering. This study uses non-Gaussian state noise to model autoregressive (AR) parameter variation with estimation by a Monte Carlo particle filter (PF). Use of non-Gaussian noise such as heavy-tailed distribution is motivated by its ability to track abrupt and smooth AR parameter changes, which are inadequately modeled by Gaussian models. Thus, more accurate spectral estimates and better ERD tracking can be obtained. This study further proposes a non-Gaussian state space formulation of time-varying autoregressive moving average (TVARMA) models to improve the spectral estimation. Simulation on TVAR process with abrupt parameter variation shows superior tracking performance of non-Gaussian models. Evaluation on motor-imagery EEG data shows that the non-Gaussian models provide more accurate detection of abrupt changes in alpha rhythm ERD. Among the proposed non-Gaussian models, TVARMA shows better spectral representations while maintaining reasonable good ERD tracking performance.     

New modified-majority voter-based efficient QCA digital logic design

ABSTRACT

Quantum-dot cellular automata (QCA) is an emerging nanotechnology and a possible alternative solution to the limitation of complementary metal oxide semiconductor (CMOS) technology. One of the most attractive fields in QCA is the implementation of configurable digital systems. This article presents a novel multifunctional gate called the modified-majority voter (MMV). The proposed gate works on the explicit interaction of the cell characteristic property for the implementation of digital circuits. This prominent feature of the proposed gate reduces the maximum hardware cost and implements highly efficient QCA structures. To verify the functionality of the proposed gate, some physical proofs, truth table and computational simulation results are performed. These results assured the validity of the existence of the proposed gate. It also dissipates less energy which has been calculated under three separate tunnelling energy levels using the QCAPro tool. To prove the effectiveness of the proposed MMV gate, several optimal irreversible arithmetic circuits such as three-input XOR, half-adder and full-adder are proposed. The modular layouts are verified with the freely available QCADesigner tool version 2.0.3.     

Tilt modulation of high resolution radar backscatter crosssections: unified full wave approach

The unified full wave approach is used to determine the tilt modulation of the like- and cross-polarized (high-resolution) radar backscatter cross sections for the rough sea surface. Real or synthetic aperture radars (SARs) with small effective footprints (resolution cells) are considered. Since the unified full-wave approach accounts for Bragg scattering as well as specular point scattering in a self-consistent manner, it is not necessary to adopt a two-scale model for the rough sea surface. The sea surface slope probability density function is assumed to be Gaussian. The backscattering cross sections are evaluated for all angles of incidence (normal to grazing). For tilts in the plane of incidence, the modulation of all the cross sections is largest at angles of incidence of 10°. The cross-section modulation due to tilts perpendicular to the plane of incidence critically depends on the incident and scattered polarizations. The effective filtering of the large-scale spectral components of the rough sea surface by the high-resolution radar is accounted for, and the dependence of the cross-section tilt modulation on the size of the effective footprint is determined     

Scattering cross sections for composite rough surfaces using the unified full wave approach

The full wave approach is used to derive a unified formulation for the like and cross polarized scattering cross sections of composite rough surfaces for all angles of incidence. Earlier solutions for electromagnetic scattering by composite random rough surfaces are based on two-scale models of the rough surface. Thus, on applying a hybrid approach physical optics theory is used to account for specular scattering associated with a filtered surface (consisting of the large sonic spectral components of the surface) while perturbation theory is used to account for Bragg scattering associated with the surface consisting of the small scale spectral components. Since the full wave approach accounts for both specular point scattering and Bragg scattering in a self-consistent manner, the two-scale model of the rough surface is not adopted in this work. These unified full wave solutions are compared with the earlier solutions and the simplifying assumptions that are common to all the earlier solutions are examined. It is shown that while the full wave solutions for the like polarized scattering cross sections based on the two-scale model are in reasonably good agreement with the unified full wave solutions, the two solutions for the cross polarized cross sections differ very significantly.     

The role of smart packaging system in food supply chain

Food supply chain is a rapidly growing integrated sector and covers all the aspects from farm to fork, including manufacturing, packaging, distribution, storing, as well as further processing or cooking for consumption. Along this chain, smart packaging could impact the quality, safety, and sustainability of food. Packaging systems have evolved to be smarter with integration of emerging electronics and wireless communication and cloud data solutions. Although there are many factors causing the loss and waste issues for foods throughout the whole supply chain of food and there have been several articles showing the recent advances and breakthroughs in developing smart packaging systems, this review integrates these conceptual frameworks and technological applications and focuses on how innovative smart packaging solutions are beneficial to the overall quality and safety of food supply by enhancing product traceability and reducing the amount of food loss and waste. We start by introducing the concept of the management for the integrated food supply chain, which is critical in tactical and operational components that can enhance product traceability within the entire chain. Then we highlight the impact of smart packaging in reducing food loss and waste. We summarize the basic information of the common printing techniques for smart packaging system (sensor and indicator). Then, we discuss the potential challenges in the manufacturing and deployment of smart packaging systems, as well as their cost-related drawbacks and further steps in food supply chain.     

Potential of pulsed electric field to control Aspergillus parasiticus,aflatoxin and mutagenicity levels: Sesame seed quality

Seed processing technologies are essential for seed safety and functionality through protection of physicochemical quality, pathogen inactivation, aflatoxin detoxification and alleviation of mutagenicity. Design of a pilot-scale unit of pulsed electric fields (PEF) to treat sesame seeds with respect to quality parameters, Aspergillus parasiticus inactivation and aflatoxin reduction as well as alleviation of aflatoxin mutagenicity were prompted in this study. PEF energy ranged from 0.97 to 17.28 J achieved maximum reductions of peroxide value and acidity number of 67.4 and 85.7%, respectively, and did not change color L*, a*, b* and hue values. A 60% reduction of A. parasiticus counts occurred at the maximum PEF energy. Aflatoxins G1, G2, B1, and B2 contents decreased by 94.7, 92.7, 86.9, and 98.7%, respectively. Except for the samples treated by 2.16 J with 100 μg/plate and by 6.80 J with 10 μg/plate, PEF treatment provided elimination of aflatoxin mutagenity. It is concluded that PEF treatment can be used to treat sesame seeds with preservation of physicochemical properties, inactivation of A. parasiticus and decomposition of aflatoxins with reduced mutagenicity.     

Long‐term oropharyngeal colonization by C. albicans in children with cystic fibrosis

This longitudinal prospective study aimed to determine the prevalence of oropharyngeal colonization by C. albicans in children with cystic fibrosis (CF), and observe the continuity of candidal colonization and the changes in production of virulence factors, susceptibility to antifungal agents and RAPD patterns of the isolates. Thirty‐seven children with CF were followed‐up for oropharyngeal C. albicans colonization for 18 months. The colonization rate was detected in 54%. All isolates were susceptible to amphotericin B, but those isolated from one patient were resistant to fluconazole. Biofilm production, secretory acid proteinase, phospholipase and esterase activity rates were 30%, 60%, 75% and 80%, respectively. RAPD analysis with the primers OPE‐03 and OPE‐18 was performed for genotyping. RAPD patterns of the strains isolated from the same patient were related to each other, whereas they were not related with other strains isolated from different patients. Two C. albicans strains isolated from the same patient were found to be unrelated to one another. As a result, long‐lasting colonization of the oropharyngeal mucosa of children with CF by endogenous C. albicans isolates having the same RAPD pattern was demonstrated. Colonization prevalance and development of resistance to antifungal agents and the increased production of virulence factors were not correlated. Copyright © 2013 John Wiley & Sons, Ltd.