Parameter Extraction Procedure Research Articles

Development of a data base for modelling adsorption of inorganics on iron and aluminum oxides

AbstractAlthough there is an abundance of data for equilibrium adsorption of inorganic ions on hydrous oxides and surface complexation models are capable of fitting the data with only a few adjustable parameters, these models have not been used in practice because of the lack of consensus as to the “best” model and the lack of a coherent compendium of equilibrium adsorption constants. To remedy this situation, a thermodynamic data base for inorganic adsorption is being developed from original data using a simple yet widely applicable model. The resulting data base can be included in general chemical equilibrium computer programs and used to predict adsorption (outside as well as within the range of calibrating data) in aqueous systems containing oxide surfaces. Both the model and the parameter extraction procedure are presented, and results for adsorption of some cations on hydrous ferric oxide are reported and discussed.

Parameter Extraction from Spaceborne MOSFETs

An addressable matrix of 32 CMOS transistors was designed into a test chip to be flown on the Combined Release and Radiation Effects Satellite (CRRES). In this paper the matrix is described along with a SPICE-like parameter extraction procedure called JMOSFIT, and Cobalt 60 radiation test results are presented that illustrate the shift in the 21-MOSFET parameters derived from JMOSFIT.

Optimized Extraction of MOS Model Parameters

A common problem faced by designers in simulating MOS circuits is the specification of model parameters. Typical parameter extraction procedures determine parameters sequentially, ignoring many of the interactions between parameters. The resulting fit of the model to measured data may be less than optimum. Furthermore, the usual extraction procedures are specialized to a particular model; considerable effort is required to accommodate improvements in the model. This paper describes the application of general-purpose optimization techniques to the problem of extracting MOS transistor parameters. With this method, all parameters are extracted in a single operation, using the Levenberg-Marquardt algorithm to find a least-squares fit of the model to measured device characteristics. The technique is independent of the MOS model used-new models may be incorporated simply by inserting the model equations into the extraction program. The optimized parameter extraction technique has been implemented and has proven effective. The ease with which the model may be changed makes the program particularly useful for the evaluation of new models.

Analysis of ECG data, for data compression.

A number of papers on the subject of data reduction techniques applied to ECG Data have recently been published; however, the authors found that most of these articles did not consider quantization techniques, which can be effectively applied to ECG data without any complex parameter extraction procedures. In this paper the authors have looked at the effects of quantization on ECG data and techniques of reducing the amount of data needed to represent these signals. Basically, 3 data reduction techniques, linear prediction using differential pulse code modulation, spectral analysis and slope change detection are investigated and a relative assessment of their performance is presented. This analysis revealed that a slope change detection, as applied to prefiltered data, can be used to represent ECG data at a rate of 2 bits/sample, while maintaining the mean squared error and peak error below 1% and 5% respectively. This technique therefore gives an effective 3 to 1 reduction over the original sampled data, since it was found that the original data could be quantized to 6 bits without significant loss of waveform information.