A neuro-fuzzy approach to automatic diagnosis and location of stator inter-turn faults in CSI-fed PM brushless DC motors

The paper presents a neuro-fuzzy-based perspective to the automation of diagnosis and location of stator-winding interturn short circuits in CSI-fed brushless dc motors. Performance of the drive under normal and short-circuit conditions are obtained through classical lumped-parameter network models. Waveforms of the electromagnetic torque and summation of phase voltages are monitored to develop two independent diagnostic algorithms. Diagnostic indices derived from the characteristic waveforms using discrete Fourier transform (DFT) lead to identifying the number of shorted turns. Fault location is achieved through a different set of indices extracted by the short-time Fourier transform (STFT). Adaptive neuro-fuzzy inference systems (ANFIS) are trained based on simulation results to automate the diagnostic process. ANFIS testing along with the good agreement between simulated and measured waveforms show the effectiveness of the proposed techniques.     

Optimized video streaming over 802.11 by cross-layer signaling

Seamless video streaming over wireless links imposes strong demands on video codecs and the underlying network. It is not sufficient that only the video codec or only the radio adapts to changes in the wireless link quality; efforts should be applied in both layers, and - if possible - synchronized. Also, the disturbing effect of possible background traffic over the same shared medium has to be taken into account. In this article we present a communication architecture for video streaming over 802.11 that is capable of adapting to changes in the link quality and sharing of the wireless channel in various use scenarios. Experimental results show that substantial improvements in the quality of the video can be obtained by applying link adaptation and cross-layer signaling techniques.     

Using a weight-of-evidence approach for management of watersheds.

This research used a weight-of-evidence approach to evaluate sources of contaminants in a drinking water watershed that serves as part of the City of Boston's water supply. The approach incorporated land use analysis using GIS, sanitary surveys, traditional water quality monitoring and microbial source tracking (MST) tools. Case-study tributaries were selected based on elevated faecal coliform counts. Land use analysis and sanitary surveys were used to identify suspected microbial sources, including residential septic systems, agricultural animal operations, commercial/industrial operations and wildlife activity. Sampling sites were selected to hydrologically isolate potential contamination sources. Samples were collected seasonally over 1 year and analysed for traditional and MST parameters. Results demonstrated that both septic systems and a horse stable were contributing microbial loads in the first tributary. In the second tributary, septic systems from the townhouses were contributing microbial loads while a plant nursery was contributing organic matter. This evidence was used to evaluate best management practices to mitigate the contamination.     

Self-service — but is it good to talk?

Drives to increase the volume of customers who use self-service channels are a common strategic goal. The promise of significant cost reduction is a tempting carrot. Couple this with the vision of customers benefiting from quick, effective and usable contact channels, avoiding human error (except perhaps their own!) or potential frustration at being passed around to an ‘appropriate’ contact centre advisor is a very worthy vision … but is it as simple as this? In this discussion paper the authors speculate that self-service, while potentially being a revenue-saving opportunity, could also erode customer satisfaction and loyalty. Self-service doubtless appeals to some customers, but is it what all customers want? Do organisations understand enough about customer experience to enable them to build successful self-service channels, i.e. those that are useful, usable and used by customers? Do businesses really want to lose the opportunity to actually talk to customers and gain insight and knowledge about them? What impact will increased levels of self-service have on more traditional channels, such as customer contact centres? This paper also discusses evidence that self-service can actually serve to increase communication between organisations and customers across multiple channels. For many organisations, the Internet has actually resulted in more calls to the contact centre, not less. The seductive promise of self-service to cut costs through reducing call volumes may be an empty one.     

Thermal networks from heat wave equation

In this paper passive and reciprocal thermal networks are introduced which model the finite velocity of heat propagation. In particular it is shown that the theory of distributed and discretized thermal networks deduced from the heat diffusion equation and the multi-point moment matching technique for deriving approximated lumped thermal networks of small state-space dimensions can be extended to thermal networks ruled by the hyperbolic heat equation.     

Effects of initial powder vibrogrinding on the properties of AlN - BN composites

A study has been made on the effects of initial vibroground powders with various grain sizes on the properties of AlN - BN composites. As the specific surface of these powders increases, so do the density, mechanical strength, and thermal resistance of the composites.     

Relation Between Firing Conditions Grain Boundary Structure and Magnetic Properties in Polycrystalline MnZn-Ferrites

The influence of the firing conditions on the nanoscale structure of the grain boundaries and on the magnetic properties of polycrystalline MnZn-ferrites is investigated, on specimens of nearly identical microstructures. High oxygen partial pressures favor accumulation of impurity ions at the triple points. Under appropriate oxygen pressures homogeneous accumulation of impurities along the grain boundaries may occur, revealing therefore chemically pure grains and low hysteresis losses; simultaneously an increase of the grain boundary resistivity occurs that results to low eddy current losses. Managing the raw material impurity cations towards controlled grain boundary structures leads to the synthesis of MnZn-ferrites with power losses similar to those achieved when high purity raw materials are used together with externally introduced additives.     

Investigation of the influence of design parameters on the flow performance of single and double disk viscous micropumps

This paper investigates the effect of radius ratio, and channel aspect ratio on the flow performance of newly introduced single and double disk viscous micropumps. A lubrication solution for the flow field, which accounts for both radius and channel aspect ratios either in single or double disk micropumps was developed and compared with available experimental data and with an approximate solution which estimates for the flow rate only in single disk pump and neglects channel aspect ratio. Additionally, a number of 3D numerical models for single and double disk micropumps were built and analyzed using the finite volume method. Pressure and drag shape factors were introduced to describe the effects of radius and channel aspect ratios on the flow rate. The values of these factors for the whole range of studied parameters are found analytically and numerically. The error in estimating the flow rate was found to be less than 10% for r ₁ /r ₂ > 0.2, and less than 7% for the studied range of h/w. Also, the lubrication solution was found to be in good agreement with the numerical and experimental results.     

Hazard Classification of Holding Ponds for Liquid Radioactive Wastes

This paper is devoted to the development of a method for hazard classification of holding ponds at the Industrial Association Mayak, the Siberian Intergrated Chemical Plant, and the Integrated Iron-Mining and Mining-Chemical Plant. The method is based on a combined approach employing the qualitative characteristics and quantitative parameters of the ponds. The classification of holding ponds is intended to be used for developing the requirements for the composition and content of the documentation presented by enterprises for licensing the operation and decommissioning of holding ponds.