Working with expert systems: Three case studies

Three case studies were conducted on the implications of the use of expert systems for the work of clerks and operators in Britain. An expert system had been introduced in a process control application. The operators' work was deskilled. The second case was a fault diagnosis application. An operator was very happy with his new work. In the third case, insurance clerks received training to operate an expert system which extended the scope of their work. In conclusion, it is suggested that expert systems extend the range of work which can be automated, but may not have unique impacts.     

Work measurement for estimating food preparation time of a bioregenerative diet

During space missions, such as the prospective Mars mission, crew labor time is a strictly limited resource. The diet for such a mission (based on crops grown in a bioregenerative life support system) will require astronauts to prepare their meals essentially from raw ingredients. Time spent on food processing and preparation is time lost for other purposes. Recipe design and diet planning for a space mission should therefore incorporate the time required to prepare the recipes as a critical factor. In this study, videotape analysis of an experienced chef was used to develop a database of recipe preparation time. The measurements were highly consistent among different measurement teams. Data analysis revealed a wide variation between the active times of different recipes, underscoring the need for optimization of diet planning. Potential uses of the database developed in this study are discussed and illustrated in this work.     

Electric properties of apple purée and pulpy apple juices

Results are presented of research, the aim of which has been to determine the selected physicochemical qualities, including electric quantities, of apple purées and pulpy juices obtained from them. The characteristics of the electric properties have covered the measurements of impedance (Z) and effective resistance (R), admittance (Y) and conductance (G), as well as equivalent parallel capacitance (Cp) and equivalent series capacitance (Cs). Changes have been determined in the purée properties relating to the technology of production as well as the function of diluting and the storage period. Apple purées, depending on the production technology, are characterized by the diversified, characteristic ranges of the resistivity and conductivity values. As the degree of the purée dilution rises, conductivity of juices falls. These relationships remain true throughout the purée storage period. In the conditions of the experiment, the measured values of resistivity and conductivity of pulpy juices clearly determine the content of apple purées in juices.     

Metallic colloid wavelength-ratiometric scattering sensors

Gold and silver colloids display strong colors as a result of electron oscillations induced by incident light, which are referred to as the plasmon absorption. This absorption is dependent on colloid-colloid proximity, which has been the basis of absorption assays using colloids. We now describe a new approach to optical sensing using the light scattering properties of colloids. Colloid aggregation was induced by avidin-biotin interactions, which shifted the plasmon absorption to longer wavelengths. We found the spectral shift results in changes in the scattering at different incident wavelengths. By measuring the ratio of scattered intensities at two incident wavelengths, this measurement was made independent of the total colloid concentration. The high scattering efficiency of the colloids resulted in intensities equivalent to fluorescence when normalized by the optical density of the fluorophore and colloid. This approach can be used in a wide variety of assay formats, including those commonly used with fluorescence detection.     

The effect of thermo-mechanical treatment on The pitting corrosion of reinforcing carbon steel bars

Steel reinforcing rods with varying amounts of cold work and carbon concentrations (0.06 to 0.45% C) exposed in soil embankments has shown various degrees of pitting corrosion. To understand this pitting process, laboratory investigations on residual stresses, microstructures and potentiodynamic cyclic polarization were undertaken. Analysis of residual stresses in the steels indicated low value of compressive stresses in hot rolled steels and high value of tensile stresses in the cold worked counterparts. Hot rolled steels displayed a slightly better pitting corrosion resistance than cold worked samples which is consistent with the above internal stress pattern. No definite correlation was obtained between the percentage of carbon in the steels and pitting susceptibility. An attempt has been made to define the role of the complex steel-soil system for pitting corrosion behavior.     

Parenting Style of Mexican, Mexican American, and Caucasian-Non-Hispanic Families: Social Context and Cultural Influences.

To begin accounting for cultural and contextual factors related to child rearing in Mexican-descent (MD; Mexican American and Mexican immigrant) families in the United States, the current study examined parenting practices in 2-parent families of Mexican, MD, and Caucasian-non-Hispanic (CNH) parents. Parents in all groups reported using authoritative practices more often than authoritarian strategies. MD parents reported greater use of authoritarian practices than Mexican and CNH parents. Results suggest that previously found cultural variations in parenting between MD parents and CNH parents may be more related to the ecological context of MD families than to an affiliation with Mexican culture. Clinicians should explore the positive qualities of authoritative parenting in MD families along with the potential motivations for using authoritarian strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Global and Local Thresholding Methods Applied to X-ray Microtomographic Analysis of Metallic Foams

X-ray based computed microtomography is a non-destructive, well established tool for a three-dimensional characterization of open-cell metallic foams. Macroscopic physical and chemical properties of these materials stay in close relation to their micro-structure parameters. The purpose of the paper is to present two types of thresholding methods so-called global and local thresholding for evaluating the structural parameters of open-cell metal foams based on X-ray microtomography data. Two different methods were chosen: automatic Otsu thresholding (global) and adaptive (mean of minimal and maximal grey values of grayscales within a selected radius). The key parameters of aluminum and nickel-chromium foams fine structure calculated using Otsu and locally thresholded images were significantly different. The proper image segmentation is the key point in metallic foam morphometry. The influence of a radius of the image processing region on the results obtained is discussed for the local thresholding method. Examples of the images artifacts generated by local thresholding method to demonstrate possible results misinterpretation are also given. The optimization of local thresholding parameter (radius of the image processing region) was presented.     

Generalized method of network calculations

Known methods of network calculation are applicable only if rigid requirements concerning the number, kind and distribution of data are met. The presented method of steady-state calculation places weak restrictions on a set of data and also permits calculations in the case of redundancy, deficiency or where the set of data is minimal. The mathematical model of a network and the calculation model are given, and a generalized inverse of matrices has been used.