Classification of audio radar signals using radial basis function neural networks

Radial basis function (RBF) neural networks are used to classify real-life audio radar signals that are collected by a ground surveillance radar mounted on a tank. Currently, a human operator is required to operate the radar system to discern among signals bouncing off tanks, vehicles, planes, and so on. The objective of this project is to investigate the possibility of using a neural network to perform this target recognition task, with the aim of reducing the number of personnel required in a tank. Different signal classification methods in the neural net literature are considered. The first method employs a linear autoregressive (AR) model to extract linear features of the audio data, and then perform classification on these features, i.e, the AR coefficients. AR coefficient estimations based on least squares and higher order statistics are considered in this study. The second approach uses nonlinear predictors to model the audio data and then classifies the signals according to the prediction errors. The real-life audio radar data set used here was collected by an AN/PPS-15 ground surveillance radar and consists of 13 different target classes, which include men marching, a man walking, airplanes, a man crawling, and boats, etc. It is found that each classification method has some classes which are difficult to classify. Overall, the AR feature extraction approach is most effective and has a correct classification rate of 88% for the training data and 67% for data not used for training.     

Starting up the Sherritt Zinc Pressure Leach Process at Hudson Bay

The first commercial application of the Sherritt two-stage zinc pressure leach process commenced operation at the Hudson Bay Mining and Smelting Company metallurgical complex in Flin Flon, Manitoba (Canada), on July 2, 1993. The start-up was relatively smooth, and full design rate for the plant was achieved by September 12, 1993. Since that time, zinc extraction in the zinc pressure leach plant has consistently been in excess of 98%, and production has continued to exceed expectations. The successful operation of the Hudson Bay plant represents a significant advancement of zinc processing technology, especially with respect to meeting the environmental challenge faced by zinc plants today.     

The performance of pigtailed annealed proton exchange LiNbO/sub 3/ modulators at cryogenic temperatures

Integrated optic modulators have been proposed for transmitting signals from electronic and electrooptic devices which must operate at 77 K and colder. In this letter, the V/spl pi/ of LiNbO/sub 3/ modulators at temperatures as cold as 10 K are measured. A /spl sim/9.25% increase over room temperature values is seen. This increase is attributed primarily to a temperature dependence in r/sub 33/. In addition, temperature-induced insertion loss changes are evaluated for two different pigtailing techniques and one is shown to be suitable for cryogenic operation.     

Measuring sea surface temperature from satellites: a ground truth approach

Determining the correction for atmospheric attenuation is a major problem in processing thermal infrared digital data from very high resolution radiometers aboard NOAA Polar Orbiting Satellites. An empirical equation for estimating this correction is developed. The coefficients of the equation are determined by using regression techniques and comparing satellite observations to sea surface temperature measurements. Although there is not sufficient data to fully evaluate this procedure, initial satellite measurements are within 0.5°C of independent sea surface temperature measurements.     

Operating-point driven formulation for analog computer-aided design

In designing analog integrated circuits, the step of selecting device sizes and biases is crucial to enhance the final performance, power, and yield of the circuits. In manual design flows, the designer first selects bias voltage and branch current values, and then converts to widths and lengths via first-order equations. This is the operating-point driven (OP) formulation. Using OP makes it easy for the designer to maintain insight of the effect of design variables (voltage, currents) on performance, in addition to simplifying the sizing problem. In contrast to manual, automated sizing approaches in the computer-aided design (CAD) literature predominantly manipulate device sizes directly. While simpler from a CAD perspective, the direct-sizing approach misses the benefits of OP—insight and a simpler problem that would lead to faster convergence and better results. We believe that the OP formulation is underused, because of lack of familiarity, inconvenience, and underappreciation of its benefits. This investigation aims to resolve that and help to improve CAD practice, by reviewing the literature on OP that has been accumulated over the decades, and describing the variants, applications, and benefits of OP.     

Geographic location of individual pixels

A major problem in processing thermal infrared digital data from very high resolution radiometers aboard NOAA Polar Orbiting Satellites is the geographic placement of digital data fields. Geographic placement is especially difficult over oceanic areas because of the lack of landmarks. Using a series of geometric constructions, an analytical approach can be developed for geographic location of individual data pixels. The errors associated with this method are generally less than 0.1° latitude and longitude.     

The emerging role of hospitalists--will family physicians continue to practice hospital medicine?

Adult intussusception is rare and is usually caused by a tumor serving as a lead point. Surgery is necessary to treat obstruction and rule out malignancy. However, if a benign cause (lipoma, fibroma, or Meckel's diverticulum) is suspected preoperatively, a minimally invasive surgical approach should be considered. This case illustrates the laparoscopic management of benign small bowel intussusception due to lipoma.     

White light spectral analysis of lithium niobate waveguides

In this paper, the usefulness of evaluating optical channel waveguides in lithium niobate with white light illumination is shown. Spectral data can be interpreted to show various regimes of waveguide operation from multi-mode to cutoff, and input coupling coefficients and attenuation factors are derived for these different modes. This technique is shown to be useful as a monitor both for process development and process consistency. Finally, both a Mach-Zehnder and a phase modulator are swept under bias and analyzed     

智能系统-模拟合成的解决方案

现实世界是一个模拟世界.说、看、听、尝是模拟功能,数据传输是模拟功能.