A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Digital processing of speech signals

Computer and Robot Vision Vol. 1, by R.M. Haralick and Linda G. Shapiro, Addison-Wesley, 1992, ISBN 0-201-10887-1.

Computer and Robot Vision

Applied Numerical Analysis. By C.F. Gerald. Pp. xii, 340. £3·60. 1970. (Addison-Wesley.)

An electrosurgical generator has an output power control system that causes the impedance of tissue to rise and fall in a cyclic pattern until the tissue is desiccated. The advantage of the power control system is that thermal spread and charring are reduced. In addition, the power control system offers improved performance for electrosurgical vessel sealing and tissue welding. The output power is applied cyclically by a control system with tissue impedance feedback. The impedance of the tissue follows the cyclic pattern of the output power several times, depending on the state of the tissue, until the tissue becomes fully desiccated. High power is applied to cause the tissue to reach a high impedance, and then the power is reduced to allow the impedance to fall. Thermal energy is allowed to dissipate during the low power cycle. The control system is adaptive to tissue in the sense that output power is modulated in response to the impedance of the tissue.

Electrosurgical generator with adaptive power control

Integrated services IP networks are expected to provide a variety of services with differentiated QoS. This requires the implementation of mechanisms that can discriminate service classes in terms of QoS. The IETF has recently proposed a differentiated services (Diffserv) framework for provision of QoS. In this paper we analyse the performance of two Diffserv mechanisms: threshold dropping and priority scheduling in terms of packet loss and mean packet delay. A comparison of the two mechanisms is carried out with the requirement that both mechanisms provide the same level of packet loss for the preferred flow. This comparison extends the results reported in the literature for these two mechanisms. In particular, in this paper we determine the impact of buffer threshold and buffer size on packet loss and mean packet delay in these mechanisms.

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Performance analysis of QoS mechanisms in IP networks

The available bandwidth in an ad-hoc network can decrease rapidly due to the shared access to the communication channel. Power control can enhance the available bandwidth by allowing non-interfering nodes to communicate simultaneously. A number of power aware topology control algorithms have been proposed, where low power transmissions are used to forward data. However evaluating the power level for the data packets is not sufficient. Reliable transmission of the data packets in a shared channel network requires a number of signalling messages at the medium access channel (MAC) layer. The transmission power of the signalling messages is crucial for both reliable access and channel reuse. We propose a distributed range assignment algorithm (DRA). That can be applied to a power aware topology control algorithm, to evaluate an appropriate power for the signalling messages. A worked example and a simulation based analysis of DRA applied to a Distributed Relative Neighbourhood Graph is provided. Furthermore, a study on the impact of the transmission range, on the power usage and channel reuse is conducted.

/pdf/distributed-range-assignment-for-reliable-channel-access-and-r3u88exgpa.pdf

Distributed range assignment for reliable channel access and reuse in ad-hoc networks

Adaptive filters are presented for improving the wavelength detection accuracy of FBG sensors within a sensing system which use tunable laser source Simulation results demonstrated that by using this technique the Bragg wavelengths of the FBG sensors can be accurately detected In addition, the filter with NMLS-OCF adaptive algorithm performs faster convergence than the other algorithms

/pdf/improving-the-measurement-accuracy-of-fbg-sensor-using-2z3cqvjv0d.pdf

Improving the Measurement Accuracy of FBG Sensor Using Adaptive filters

This paper studies the problem of blind separation of convolutive mixtures by means of Kullback-Leibler divergence in frequency domain. Unlike exiting approaches, an integrated objective function is defined in frequency-domain with time-domain parameters as the variables. The permutation problem is avoided through the frequency-domain integration and time-domain optimization. Simulation results show that the algorithm is valid and of high performance for the separation of real-world recorded convolutive mixtures.

/pdf/a-half-frequency-domain-approach-for-convolutive-blind-2ssfu7f4n2.pdf

A half-frequency domain approach for convolutive blind source separation based on Kullback-Leibler divergence

We have demonstrated a novel Fiber Bragg Grating sensing system based on a Fabry-Perot tunable filter for measuring dynamic processes This system is very suitable for multipoint vibration or dynamic strain detection However, in some conditions, the response time of Fabry-Perot tunable filter will influence the sensitivity of the sensor that the sensitivity is not kept constant Therefore, post-processing for the measured vibration signal is necessary to solve this problem In this paper, the demodulation technique of this system is briefly described and two signal processing methods are introduced to deal with the measured signal to obtain stable measurement of the vibration/dynamic strain over the response time of Fabry-Perot tunable filter In the experiment, program controlled multipoint dynamic strain detection is successfully implemented by this system with these signal processing methods

/pdf/signal-processing-methods-implemented-in-a-novel-fbg-sensing-1v2s4xgrh0.pdf

Joe F. Chicharo

Papers

Performance analysis of QoS mechanisms in IP networks

Distributed range assignment for reliable channel access and reuse in ad-hoc networks

Improving the Measurement Accuracy of FBG Sensor Using Adaptive filters

A half-frequency domain approach for convolutive blind source separation based on Kullback-Leibler divergence

Signal processing methods implemented in a novel FBG sensing system for vibration/dynamic strain measurement