1,721,053 research outputs found
A Systems View of Learning in Education
No full textAs the sophistication of technology has increased, so has public demand for quality. This expectation of quality has occurred across a broad range of products and systems, including education. To meet the demand for quality, many products and systems (including educational ones) have become increasingly complex. Within education there are also other factors which have driven up levels of complexity. These factors include increased diversity in the student body, a greater emphasis on collaboration and the drive to replace simple "delivery models" of teaching. It is well known from other fields, though, that as systems become more complex, they become more vulnerable to failure. For this reason, a formalised methodology known as "systems engineering"\ud
is often applied in industry to the management of large systems. The author argues that the use of systems engineering concepts in education would be likely to reduce failure rates and improve quality. This is particularly so in large-scale complex learning systems. The paper also discusses some implications of trying to use systems engineering methodology in modern educational systems
A high-resolution spectral analysis algorithm for power-system disturbance monitoring
No full textIn a previous paper, the author presented a Fourier-based algorithm for monitoring the characteristics of the damped oscillating "modes" which are set up after a disturbance in an electric power-distribution system. This earlier paper permitted the analysis of multiple modes but only if the modes were sufficiently well separated to be resolved with conventional Fourier techniques. This current paper extends the previous work to enable the processing of multiple modes which are very closely spaced in frequency. Importantly, the proposed algorithm has good noise performance. A theoretical justification for the new method is presented, and simulations are provided to confirm the theory. The scheme is also tested on a real power-system example
Improving polynomial phase parameter estimation by using nonuniformly spaced signal sample methods
No full textThis paper investigates the computationally efficient parameter estimation of polynomial phase signals embedded in noise. Many authors have previously proposed multilinear analysis methods which operate on uniformly spaced samples of the signal. Such methods include the higher-order ambiguity functions (HAFs), the Polynomial Wigner-Ville distributions (PWVDs) and the higher-order phase (HP) functions. This paper investigates the use of multilinear methods which operate on nonuniformly spaced signal samples. It is seen that the relaxation of the requirement to use uniformly spaced samples in the analysis can lead to significant performance improvements. A theoretical analysis and simulations are presented in support of these claims
A fast algorithm for estimating the parameters of a quadratic FM signal
No full textThis paper describes a fast algorithm that can be used for estimating the parameters of a quadratic frequency modulated (FM) signal. The proposed algorithm is fast in that it requires only one-dimensional (1-D) maximizations. The optimal maximum likelihood method, by contrast, requires a three-dimensional (3-D) maximization, which can only be realized with an exhaustive 3-D grid search. Asymptotic statistical results are derived for all the estimated parameters. The amplitude estimate is seen to be optimal, whereas the phase parameters are, in general, suboptimal. Of the four phase parameter estimates, two approach optimality as the signal-to-noise ratio (SNR) tends to infinity. The other two have mean-square errors that are within 50% of the theoretical lower bounds for high SNR. Simulations are provided to support the theoretical results. Extensions to multiple components and higher order FM signals are also discussed
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