A CMOS monolithic amplifier for cardiac EIT applications

Analog Integrated Circuits and Signal Processing - This paper presents a low-noise amplifier (LNA) with superior linearity for ultra-wideband (UWB) purposes. Linearity is a significant parameter...     

Effects of firm and IT characteristics on the value of e-commerce initiatives: An inductive theoretical framework

We explore the theoretical foundations on how firm and IT characteristics explain the market value variations in e-commerce initiatives by examining the announcements of 946 e-commerce initiatives in the public media. Our approach combines the Event study methodology and Decision tree induction to examine the main and interaction effects of IT and firm characteristics on Cumulative Abnormal Returns (CAR). In particular, we generate complex interaction models that can guide e-commerce investment decisions so managers can know, for example, which combination of IT and firm characteristics are more likely to be viewed positively by investors. The selected study variables as well as explanation of the proposed framework are informed by innovation, resource-based view, transaction cost economics and complementarity theories. We have inductively developed a set of propositions that can be deductively tested to assess the validity of our proposed theoretical framework. Hence our study provides an initial roadmap for theory development on e-commerce and CAR.     

EFFECTS OF COAL SURFACE CHARGE ON THE ADSORPTION AND GASIFICATION ACTIVITIES OF CALCIUM AND POTASSIUM

ABSTRACT

The electrokinetic properties of lignite, subbituminous and bituminous coal particles and their demineralized derivatives have been measured as a function of pH. Compared to the raw coals, demineTalization generally increased the net negative surface charge densities on the coals. Calcium or potassium adsorption (by ion-exchange) onto the demineralized coals was strongly dependent on pH and the surface charge properties of the coals. Metals uptake was very low (0,1-0.4% wt.) in strongly acidic media (～pHl) but increased dramatically as the net negative charge on the coals was increased by increasing the pHs of the coal suspensions to pH 6 or 10. The reactivities of the calcium- ot potassium-loaded chars in carbon dioxide at 800^°C were similarly dependent upon the pHs at which the catalysts were ion-exchanged onto the coals. For the calcium-containing chars, the reactivities increased in the order: pH 6 > “pH 10 > pH 1 while the variation of the gasification rates with potassium loading pH was: pH 6 ～ pH 10 ? pH I. These findings are attributed to differences in the extent of electrostatic interaction between the calcium or potassium ions and the charged coal surface during catalyst loading from solution.     

An energy-efficient spike encoding circuit for speech edge detection

In speech processing applications, the instantaneous bandwidth of speech can be used to adaptively control the performance of an audio sensor’s analog front end. Extracting the instantaneous bandwidth of speech depends on the detection of speech edges in the time–frequency plane. In this paper, we propose a spike encoding circuit for real-time and low-power speech edge detection. The circuit can directly encode the signal’s envelope information—an important feature to identify the speech edge—by temporal spike density without additional envelope extraction. Furthermore, the spike encoding circuit automatically adapts its resolution to the amplitude of the input signal, which improves the encoding resolution for small signal without increasing the power consumption. We use the nonlinear dynamical approach to design this circuit and analyze its stability. We also develop a linearized model for this circuit to provide the design intuition and to explain its adaptive resolution. Fabricated in 0.5-μm CMOS process, the spike encoding circuit consumes 0.3-μW power and the experimental results are presented.     

A comparative review of dynamic neural networks and hidden Markov model methods for mobile on-device speech recognition

The adoption of high-accuracy speech recognition algorithms without an effective evaluation of their impact on the target computational resource is impractical for mobile and embedded systems. In this paper, techniques are adopted to minimise the required computational resource for an effective mobile-based speech recognition system. A Dynamic Multi-Layer Perceptron speech recognition technique, capable of running in real time on a state-of-the-art mobile device, has been introduced. Even though a conventional hidden Markov model when applied to the same dataset slightly outperformed our approach, its processing time is much higher. The Dynamic Multi-layer Perceptron presented here has an accuracy level of 96.94% and runs significantly faster than similar techniques.

     

Factor structure of the Child Behavior Checklist/6-18 in a sample of girls adopted from China.

Confirmatory factor analysis with robust weighted least squares estimation of the 103 dichotomously scored items of the Child Behavior Checklist/6-18 (T. M. Achenbach & L. A. Rescorla, 2001) in a sample of 516 girls adopted from China (ages 6.0-15.7 years; M = 8.2, SD = 1.9) indicated that the fit of the 8-factor model was good (root-mean-square error of approximation = .047) and was slightly better than what T. M. Achenbach and L. A. Rescorla (2001) reported for the same model (.06). Support for the 2nd-order factor structure of Internalizing and Externalizing Problems also was provided. Comparisons of the mean scores for the syndromes and Internalizing, Externalizing, and Total Problems revealed mostly small differences between the sample of adopted Chinese girls and T. M. Achenbach and L. A. Rescorla's normative samples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydraulic Conductivity of Soils from Grain-Size Distribution: New Models

This paper presents new developments of regression-based models to predict the saturated hydraulic conductivity of compacted soils from grain-size distribution. The models incorporate parameter values that adequately represent the distribution of grain sizes. Alternative representations of the grain-size distribution, the fractal dimension and entropy of the distributions, as well as porosity, soil density, and fines content are used in the models to estimate the hydraulic conductivity. These parameters that characterize the textural and hydraulic properties of the soil are combined and used in a multidimensional analysis to estimate the hydraulic conductivity. The predictions of the developed models are compared with those of existing models and laboratory measurements of hydraulic conductivity. The results suggest that the newly developed models outperform the existing models in predicting hydraulic conductivity using information from grain-size distribution. The presented models are suggested as alternatives to, for example, laboratory measurements of the hydraulic conductivity of certain soils that may be difficult to prepare or that may take several days or perhaps weeks to perform. In certain circumstances it may also be used to give first-hand information about the hydraulic properties in a field environment.     

Palm kernel shell as fuel for burning bricks

The use of an agricultural waste product, palm kernel shell, as a fuel for firing bricks is explored as a means of reducing environmental degradation and depletion of scarce firewood in Ghana. A simple but efficient methodology of clamp firing bricks using the new fuel is developed and tested. The resulting bricks are analysed for physical properties and suitability for construction use. The viability of palm kernel shell as a fuel for small-scale brick industries is considered. On etudie actuellement au Ghana les possibilites d'utilisation d'un dechet agricole, en l'occurrence, les coquilles de noix de palme, comme combustible dans les briqueteries; une telle solution permettrait de reduire la degradation de l'environnement et de diminuer l'appauvrissement des maigres reserves en bois de chauffage du pays. A cet effet, on met au point une methodologie simple mais efficace de cuisson des briques en brulant des dechets de coquilles de noix de palme. On analyse les proprietes physiques de ces briques et on verifie qu'elles conviennent a la construction. On etudie la viabilite de la coquille de noix de palme pour l'alimentation en combustible des petites briqueteries.