Efficient design of gallium arsenide Muller-C element

A Muller-C element is a fundamental building block of a handshake path in self-timed digital circuits. It is a basic event driven logic (EDL) gate, implementing the AND function for events. The authors present a new, improved design of the Muller-C element using GaAs MESFET technology. A static Muller-C gate is implemented that incorporates modifications of newly introduced, GaAs pseudodynamic latched logic family (PDLL) primitives. The circuit is characterised by very high speed and low power dissipation     

Media-independent pre-authentication supporting secure interdomain handover optimization [architectures and protocols for mobility management in all-IP mobile networks]

Handovers may cause delays and packet losses that affect real-time communication performance. Mobility protocols at several layers are designed to support handover, but they need to be optimized to ensure high-quality application performance. Existing optimization techniques are not sufficient to take care of interdomain and intertechnology handovers involving different access technologies, such as Wi-Fi, GSM, CDMA, and WiMAX. We categorize several types of handover, describe handover delay components, and propose a handover optimization framework called media independent pre-authentication that can provide optimizations for interdomain and intertechnology handover in a manner that is transparent to mobility management protocols. In addition, we also present experimental results demonstrating that this framework can achieve a significant reduction in handover delays for both network-layer and application-layer mobility management protocols.     

Alzheimer's diagnosis using eigenbrains and support vector machines

An accurate and early diagnosis of the Alzheimer's disease (AD) is of fundamental importance for the patient's medical treatment. Single photon emission computed tomography (SPECT) images are commonly used by physicians to assist the diagnosis. Presented is a computer-assisted diagnosis tool based in a principal component analysis (PCA) dimensional reduction of the feature space approach and a support vector machine (SVM) classification method for improving the AD diagnosis accuracy by means of SPECT images. The most relevant image features were selected under a PCA compression, which diagonalises the covariance matrix, and the extracted information was used to train an SVM classifier, which could classify new subjects in an unsupervised manner.     

Spectral fuzzy classification: an application

Geographical information (including remotely sensed data) is usually imprecise, meaning that the boundaries between different phenomena are fuzzy. In fact, many classes in nature show internal gradual differences in species, health, age, moisture, as well other factors. If our classification model does not acknowledge that those classes are heterogeneous, and crisp classes are artificially imposed, a final careful analysis should always search for the consequences of such an unrealistic assumption. We consider the unsupervised algorithm presented by A. del Amo et al. (2000), and its application to a real image in Sevilla province (south Spain). Results are compared with those obtained from the ERDAS ISO-DATA classification program on the same image, showing the accuracy of our fuzzy approach. As a conclusion, it is pointed out that whenever real classes are natural fuzzy classes, with gradual transition between classes, then its fuzzy representation will be more easily understood, and therefore accepted by users     

Editorial: Security and Privacy in Internet of Things

Mobile Networks and Applications -     

Plasma enhanced chemical vapor deposition of SiO2 films at low temperatures using SiCl4 and O2

Silicon dioxide films have been deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD) technique using SiCl₄ and O₂ as reactive materials. Infra-red transmittance, Auger electron spectroscopy analysis, ellipsometry, electrical, and chemical etch measurements have been used to characterize these films. It is possible to obtain good quality oxides at a substrate temperature of 200° C using a low flow of reactant gases. High flow of reactant gases results in highly non-homogeneous porous films. The best oxide films obtained show destructive breakdown at electrical fields above 4 MV/cm and a fixed charge density of the order of 2.6 × 10¹¹ charges/cm².     

Design of Two‐Stage Class AB CMOS Buffers: A Systematic Approach

A systematic approach for the design of two‐stage class AB CMOS unity‐gain buffers is proposed. It is based on the inclusion of a class AB operation to class A Miller amplifier topologies in unity‐gain negative feedback by a simple technique that does not modify quiescent currents, supply requirements, noise performance, or static power. Three design examples are fabricated in a 0.5 µm CMOS process. Measurement results show slew rate improvement factors of approximately 100 for the class AB buffers versus their class A counterparts for the same quiescent power consumption (< 200 µW).     

A new method to quantify retention-failed cells of an EEPROM CAST

The cell array stress test (CAST) is a very simple tool to study one of the main issues of Non Volatile Memory reliability: data retention. However, it is not possible to easily quantify and localise the retention-failed cells of a CAST. Thus, a new experimental technique to localize and to quantify retention-failed EEPROM cells into a CAST is presented in this paper. This new technique is based on light emission microscopy; the aim is to observe light emission coming from cells and to localize their position with accuracy on CAST area. It is a visual and non destructive method which validity has been shown on cycled cells after a retention test.     

Fat properties during homogenization, spray-drying, and storage affect the physical properties of dairy powders

Changes in fat properties were studied before, during, and after the drying process (including during storage) to determine the consequences on powder physical properties. Several methods were combined to characterize changes in fat structure and thermal properties as well as the physical properties of powders. Emulsion droplet size and droplet aggregation depended on the homogenizing pressures and were also affected by spray atomization. Aggregation was usually greater after spray atomization, resulting in greater viscosities. These processes did not have the same consequences on the stability of fat in the powders. The quantification of free fat is a pertinent indicator of fat instability in the powders. Confocal laser scanning microscopy permitted the characterization of the structure of fat in situ in the powders. Powders from unhomogenized emulsions showed greater free fat content. Surface fat was always overrepresented, regardless of the composition and process parameters. Differential scanning calorimetry melting experiments showed that fat was partially crystallized in situ in the powders stored at 20°C, and that it was unstable on a molecular scale. Thermal profiles were also related to the supramolecular structure of fat in the powder particle matrix. Powder physical properties depended on both composition and process conditions. The free fat content seemed to have a greater influence than surface fat on powder physical properties, except for wettability. This study clearly showed that an understanding of fat behavior is essential for controlling and improving the physical properties of fat-filled dairy powders and their overall quality.