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New Publications are available now online for this publication.
Please follow the links to view the publication.Predictive PID controller for DC-DC converters using an adaptive prediction error filter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0213
This paper presents a predictive PID controller for DC-DC converters using an adaptive prediction error filter (PEF) in the controller feedback loop. The concept of using an adaptive PEF is clearly described, and mathematical analysis of central concepts, such as the Auto-Regressive (AR) process generator and Moving Average (MA) identifier are explained in detail. The direct relationship between an adaptive PEF and a digital Proportional-Derivative (PD) controller is also presented. This leads to the development of an adaptive Proportional-Derivative + Integral (PD+I) control structure which is an effective substitute to a conventional PID controller. Experimental validation shows that the approach results in a fast adaptive controller with self-loop compensation. (6 pages)Mining important predictors of heart attack
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0067
Risk of heart attack is a global issue. This paper attempts to mathematically model the influence of eleven predictors on the heart attack risk. The contribution of each predictor and the related risk of heart attack are obtained from a group of medical doctors. Total 300 such cases are structured in a 300 * 12 matrix to conduct the study. Using statistical data mining, significant joint predictors have been extracted and clinically validated. The study also measures the variations in interpretations among doctors.Using Canny algorithm in QEM simplification for textured 3D models
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0900
In this paper, based on edge collapse an improved method of texturing 3D models is promoted, which take the texture into and consideration and make use of Canny algorithm to calculate the borders. We use edge collapse algorithm to simplify the 3D models and the collapse sequence is depended on the collapse cost which combine the edge collapse and the texture collapse. Before simplification, fist using Canny algorithm to calculate the border of the model to keep the basic skeleton of the models.The hierarchical system modeling for the planning of comprehensive passenger transportation hub nodes
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1369
The planning of large systems is always organized in a distributed hierarchy. Comprehensive passenger hub nodes are composed of many different elements. In this paper, the hierarchical system modelling for the comprehensive passenger hub nodes in the provincial area is researched. In the model, the cluster method is chosen and the indexing system for the hierarchical system is also established. Besides the analysis of the transport factor, the social and economic factors are also considered in the indexing evaluation so as to reflect the source of the passengers going out. At last, the planning of Jiangsu provincial comprehensive passenger hub nodes is selected as an example to illustrate the model application. The results show that the fourth hierarchical clusters of hub nodes in Jiangsu province are obtained. And for each cluster, differentiation strategy is put forward to clear its functional and logical location. The hierarchical system modelling to guide the planning work shows the good results.An abstract to calculate big O factors of time and space complexity of machine code
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0483
Algorithms are generally written for solving some problems or mechanism through machines, the algorithms may be several in numbers, further to these the efficiency of the produced algorithms for the said issue need to be quantified: the factors which are to be quantified are time complexity, space complexity, administrative cost and faster implementation etc.,..One of the effective methods for studying the efficiency of algorithms is Big-O notations, though the Big-O notation is containing mathematical functions and their comparison step by step, it illustrates the methodology of measuring the complexity facto. The output is always expected as a smooth line or curve with a smaller and static slope.Comparison of single-phase cascaded and multilevel DC link inverter with pulse width modulation control methods
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0366
This paper presents comparison of cascaded H-Bridge and multilevel dc link inverter using only a dc power sources. The performance of a seven level multilevel dc link inverter based on sine and space vector pulse width modulation control technique. Performance analysis is made based on the results of simulation study conducted on the operation of the multilevel dc link inverter using MATLAB/SIMULINK. The performance parameters chosen in the work include the waveform pattern harmonic spectrum, fundamental value and total harmonic distortion (THD) of the single phase multilevel dc link inverter.Effect of fractional-order controller on automatic generation control of a multi-area thermal system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0365
A concept of fractional order (FO) control has received an increasing interest recently in the control areas. This paper investigates the effect of a fractional-order Proportional plus Integral plus Derivative (FOPID) controller in automatic generation control (AGC) of interconnected two unequal and three unequal area thermal systems considering appropriate generation rate constraint (GRC). Integral square error (ISE) criteria have been used as performance index to design the optimal controller keeping frequency bias setting fixed at frequency response characteristics. The performance of FOPID controller is investigated and compared with several integer-order (10) classical controllers such as integral (I), Proportional plus Integral (PI), Proportional plus Integral plus Derivative (PID). The optimum value for several parameters is obtained using classical approach minimising cost function J. Studies reveal that FOPID controller having five tuning knobs are quite robust and provide superior dynamic performances in terms of settling time and reduction in oscillation of frequency and tie line power deviation dynamic response as compared to all the conventional 10 controllers. System performances are examined with 1% step load perturbation in ureal.Optimum power flow control algorithm for an ultracapacitor bidirectional DC-DC converter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0158
In this paper, new modulation schemes are proposed to minimise the circulating power flow, minimise RMS currents and maximise the operating efficiency of a voltage-fed phase-shifted bidirectional DC-DC converter for an ultracapacitor energy buffer, with an IGBT voltage doubler circuit. The mathematical analysis to obtain an optimum power flow controller of the bidirectional converter is presented. Theoretical and simulation results show that the proposed method can maintain minimum circulating power flow even if the ultracapacitor voltage is fluctuating between 50% and 100% of the rated voltage. Furthermore, using the proposed modulation methods a considerable improvement in converter efficiency (up to 93.4%) is achieved in comparison to that for the conventional phase-shift modulation method (around 80%). The proposed modulation scheme is verified by PSpice/Simulink co-simulation using SLPS. (7 pages)Audio-visual convolutive blind source separation
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0225
We present a novel method for speech separation from their audio mixtures using the audio-visual coherence. It consists of two stages: in the off-line training process, we use the Gaussian mixture model to characterise statistically the audio- visual coherence with features obtained from the training set; at the separation stage, likelihood maximization is performed on the independent component analysis (ICA)-separated spectral components. To address the permutation and scaling indeterminacies of the frequency-domain blind source separation (BSS), a new sorting and rescaling scheme using the bimodal coherence is proposed. We tested our algorithm on the XM2VTS database, and the results show that our algorithm can address the permutation problem with high accuracy, and mitigate the scaling problem effectively. (5 pages)Towards a method to determine the glottal formant parameters of voiced speech without time-domain references
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0494
This paper presents an approach to estimate the glottal formant parameters of the voicing source in the frequency-domain. The method is based on a simplified pole-zero interpretation of the prevalent Liljencrants-Fant (LF) model of glottal flow, and gives approximations for a broad range of pulses shapes. An advantage of the method is that, unlike other methods, it does not rely on time-domain references.Research on image filtering method to combine mathematics morphology with adaptive median filter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1152
As a imaging technology of no-traditional lamp-house irradiation ,ultrasound medical imaging with its many advantages, such as no harm to the human body, real-time, cheap and easy to use, is widely used in clinic. But the ultrasonic imaging speckle noise make it difficulties to distinguish between normal tissue and pathological tissue. According to the character of noise in the medical ultrasonic image , an new method of the medical ultrasonic imaging filter based on mathematics morphology and adaptive filtering is proposed after analysis of speckle noise and general filter, and an experiment is made to validate. The experimental method is as follows : Firstly the Rayleigh noise is imposed on the original image , and then the median filter and the adaptive median filter are used on the contaminated image. Secondly the morphological filter is used to improve image quality and enhance the contrast , after the adaptive median filter is used on the image, to retain more necessary details. Finally the three noise filtering methods are compared from the images denoise and evaluation . And the results indicate that the new method is superior to other ones.Performance analysis of eXplicit Control Protocol (XCP)
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0613
Mathematical analysis of current congestion control algorithms reveals that, as the delay-bandwidth product (BDP) increases, TCP becomes more oscillatory and prone to instability, regardless of the queuing scheme. To address this problem, a novel approach to Internet congestion control is developed recently. This new explicit Control Protocol (XCP) delivers the highest possible application performance over a broad range of network infrastructure, including extremely high speed and very high delay links that are not well served by TCP. We analyze the performance of XCP and make comparation with TCP. Extensive simulations show that XCP achieves fair bandwidth allocation, high utilization, small standing queue size, and near-zero packet drops, with both steady and highly varying traffic. In this paper, we investigate the XCP in deep sight; also present a simple network in which XCP is locally stable but globally unstable in the presence of latency. The simulation results verify that XCP remains fairness, high utilization for future high bandwidth-delay product network.Adaptive tools to conduct harmonic analysis using time domain software
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1012
The non-linear behaviour of HVDC converters causes distorted voltage and current waveforms in the HVAC network to which it is connected. Typically frequency domain software is used for conducting harmonic analysis (penetration and impedance scan studies) and results are displayed as steady-state quantities not taking into account the dynamic behaviour of the system components. A time domain software package is utilized to perform harmonic analysis and consider the dynamic behaviour of the system components. Thus the contribution of this work is the development of adaptive (compact) tools to simplify harmonic analysis procedures for investigating integrated HVAC/HVDC systems using time domain software. Results are generated and it is found that the developed tools are effective for conducting harmonic analysis using time domain software. (5 pages)SystemC-A modelling of mixed-technology systems with distributed behaviour
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0137
This paper presents an approach to modelling distributed systems described by Partial Differential Equa tions(PDEs) in SystemC-A. Such modeling approach is quite important because of the modeling difficulties for the mixed physical domain systems where complex digital and analogue electronics interfaces with vital distributed physical effects. As current SystemC-A does not support PDEs modeling, the proposed approach is based on discretization of PDEs to a set of Ordinary Differential and Algebraic Equations(ODAEs) which can be solved. Future work will extend the SystemC-A syntax to provide full PDE support. Distributed lossy microstrip and cantilever beam are used to validate the method and are described in the case studies.HVAC/HVDC strategy for solving power delivery shortages to a localised area of a national grid
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1011
The industrial and population growth can cause power delivery problems to a localised area of a national grid. One reason for these power shortages is the insufficient current carrying capacity of existing HVAC transmission line supplying the area. Parallel HVAC line, a HVDC line or combinations of HVAC-HVDC lines are three possible solutions to improve power delivery. This paper investigates the various line possibilities using a cutting edge time domain software tool. The contribution of this work is the development of a strategy (flowchart) involving individual or combinations of HVAC and/or HVDC transmission lines taking into account important decision making factors. Simulation based case studies are conducted as part of the strategy and the results are verified. These results together with the decision making factors are then used to demonstrate that an integrated HVAC-HVDC system could be the chosen solution. The developed strategy is shown to be an effective planning tool. (5 pages)The reverse design method for cam contours and motion specification
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1471
In the view of the difficult problem to receive the original design of the cam and its follower motion specification, an efficient, rapid and accurate reverse design for cam mechanisms is provided. This paper does research on the motion specification of cam mechanisms through establishing mathematical model L motion simulation and analysis. Firstly L amends the measured parameters achieved by the CMM and works out the reverse equation of cam profile curve by the established mathematical model. Secondly, applying the revised parameters which works out by the reverse equation of cam profile curve and motion simulation to obtain the cam mechanism follower motion specifications. In order to verify the method of measurement and reverse of the motion specification of cam, a cylindrical cam is adopted as an example and PRO/E motion simulation is applied to achieve its kinematics analysis and motion specification. In the light of this experiment result, it proves that the motion specification of follower can be realized rapidly and accurately. (4 pages)Some remarks on the well-posedness of the EMD algorithm
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1726
We identify two major difficulties with the formulation of a rigorous mathematical theory for the Empirical Mode Decomposition (EMD): a) the concept of the envelope is not well defined, and b) the output of the EMD fails a very simple consistency criterion. (6 pages)The method of making production plan in mass customization
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1509
This paper studies the method of making production plan in mass customization. It illuminates that all current methods of making production plan are not suitable for mass customization by analysing the lacks of these methods, and sets up the new method of making production plan in mass customization. The new method can make out the optimize production plan by the math model which is suitable for the case in mass customization. In the models,it is not only considering the production order information from the virtual zoology modularization enterprise information integration flat and rough ability balance, but also considering the weightiness in management and order, the length of the delivery date, and the cost of customization product, the target cost of customization product and the standard product cost. Finally, it makes out a production plan with its models by simulating the case of a mass customization manufactory. (5 pages)A comparison of wideband beamformers in coherent situations
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0298
In this paper, we compare the performance of two classes of adaptive beamformers for wideband and coherent signals. It is well known that when the desired signal and interferences are partially or completely correlated, performance of conventional beamformer degrades severely. Therefore, spatial smoothing method and frequency focusing method have been proposed to tackle coherent sources. In this paper, we first discuss a frequency focusing method which is based on time-domain and can be applied to real time systems. And then, a new wideband beamformer was proposed by introducing spatial smoothing method into Frost beamformer. Result of simulations shows that the new beamformer has better frequency response than the time-domain based frequency focusing beamformer. (4 pages)Musical noise reduction based on spectral subtraction combined with Wiener filtering for speech communication
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.2056
The goal of this paper is to propose a new technique for musical noise reduction used to alleviate some of the speech distortion introduced by the spectral subtraction (SS) process, particularly to eliminate the background musical noise of actual environment in speech communication or recognition system. The new speech enhancement approach combines spectral subtraction and the conventional Wiener filtering (CWF) in series connection to construct a two-stage hybrid system (named SS-CWF) in frequency domain to enhance the speech with additive musical noise. The noisy speech is recorded under the real background musical noise environment at a relatively lower signal-to-noise ratio. Simulation results of the proposed method, comparing with that of the conventional spectral subtraction, show better performance. The performance is evaluated by using the Log Likelihood Ratio (LLR) measure, which is an objective evaluation measure based on linear predictive coding (LPC) techniques. Experiment results have shown that combination SS-CWF method is more robust and efficient. Meanwhile, the subjective evaluation results indicate that this method provides better speech quality with cleaner waveforms and spectrograms in time and frequency domain. Consequently, the proposed technique has complementary advantages of the spectral subtraction and Wiener filter.TEPCO-BCU for on-line dynamic security assessments of large-scale power systems
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1874
The current direction of development for fast transient stability assessment is to combine a reliable direct method and a fast time-domain method into an integrated methodology to take advantage of the merit of both methods. TEPCO-BCU is developed under this direction by integrating BCU method, BCU classifiers, and BCU-guide time domain method. Current version of TEPCO-BCU is able to perform exact stability assessment and accurate energy margin computation of each contingency of large-scale power systems. Exact stability assessment is meant to classify stable contingencies as stable and unstable contingencies as unstable while accurate energy margin computation is meant to give accurate critical clearing time of each contingency of large-scale power systems. To bypass the difficulty of checking the one-parameter transversality condition of BCU method, the concept of the boundary property has been proposed and a group-based BCU method has been developed. This paper has described on-line transient stability assessment results of TEPCO-BCU program on a 12,000-bus power system data. Feasibility study of applying Parallel TEPCO-BCU to on-line transient stability evaluation in terms of speed and accuracy of stability assessment has been conducted. It has been found that the wall clock time needed to process 3,000 contingencies on the 12,000-bus system is 29.5 minutes, 15.5 minutes and 3.1 minutes respectively on a 1-node, 2-node and 10-node configurations. Given a credible list of contingencies, TEPCO-BCU system can fast screen out critical contingencies. This capability in conjunction with some relevant functions can lead to several practical applications. These relevant functions include the energy function method, the controlling UEP coordinates and their sensitivities with respect to parameters or control actions. (14 pages)Shape-based image retrieval
http://dl-live.theiet.org/content/conferences/10.1049/ic.2009.0150
In many applications, the user of an image database system points to an image, and wishes to retrieve similar images from the database. Computer vision researchers aim to capture image information in feature vectors which describes shape, texture and color properties of the image. These vectors are indexed or compared to one another during query processing to find images from the database. This paper is concerned with shape similarity retrieval in image databases. Edge Direction Histogram (HED) and Fourier Descriptors are used for extracting shape features. The proposed method is tested on a standard database of MPEG-7 CE-1 Part-B database of 1400 images. Results of HED method are compared with Fourier descriptor method. The results of HED method show the promising performance and its superiority over the Fourier descriptor method. (4 pages)A preliminary analysis of HIV infection dynamics
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080668
Several dynamic models of the behaviour of HIV infection are reviewed. Important features of the models examined are the inclusion of the effects of anti-retroviral drugs, virus mutation and latent infection. For the models including virus mutation mathematical analysis yields a complete description of all possible equilibria and their local stability properties. For the cases considered, we can prove that generically, there are only two valid equilibria: (i) the locally unstable uninfected equilibrium and, (ii) the locally stable infected state equilibrium.Speech emotion verification system (SEVS) based on MFCC for real time applications
http://dl-live.theiet.org/content/conferences/10.1049/cp_20081108
Human recognizes speech emotions by extracting features from the speech signals received through the cochlea and later passed the information for processing. In this paper we propose the use of Mel-frequency cepstral coefficient (MFCC) to extract the speech emotion information to provide both the frequency and time domain information for analysis. Since features extracted using the MFCC simulates the function of the human cochlea, neural network (NN) and fuzzy neural network algorithm namely; multi layer perceptron (MLP), adaptive network-based fuzzy inference system (ANFIS) and generic self-organizing fuzzy neural network (GenSoFNN) were used to verify the different emotions. Experimental results show potential of using these techniques to detect and distinguish three basic emotions from speech for real-time applications based on features extracted using MFCC. (7 pages)The solve of the high profit development of the tourism destination
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080775
For the purpose which can estimate the quantity of the people with different consumption levels in the sightseeing industry, on the basic of the mathematical model of layer analysis, we use the neural net forecasting arithmetic with the contentment level, achieve the aim of foresee the benefit of the tourism destinations. For the purpose providing the plan of tourism destinations exploitation, imbed optimal analysis method with the use of the forecasting arithmetic, use the exhaustive method in small-scale and low-precision, and use the genetic algorithms in the big-scale and high-precision, achieve to provide the most efficient and the most reasonable exploitation plan for the developers.Using mathematical models to guide the simulation of improvised explosive devices in public spaces
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080716
Terrorist attacks, for example in Madrid and London, have increased concern over the threat that Improvised Explosive Devices (IEDs) pose to public safety. Insurgent groups in Iraq and Afghanistan have developed relatively sophisticated tactics, including the use of synchronised attacks with multiple devices that have not yet been witnessed in Europe or North America. Some of these approaches specifically target the fire and rescue services. Computer simulations provide tools that can be used to plan the response to potential attacks. They can be used to work through a range of scenarios so that emergency personnel minimise their vulnerability and mitigate the threat posed to the general public. However, it can be difficult to simulate the range of human behaviours that are seen in the aftermath of terrorist attacks. Similarly, it is unclear how to develop appropriate blast and fragmentation models that capture a range of future Improvised Explosive Devices. The following pages present a brief overview of mathematical models that are being integrated into simulation tools to address these problems. (6 pages)Application of supervised learning artificial neural networks [CPNN, BPNN] for solving power flow problem
http://dl-live.theiet.org/content/conferences/10.1049/ic_20070603
Power flow study is performed to determine the power system static states at each bus to find the steady state operating condition of a system. Power flow study is the most frequently carried out study performed by power utilities and it is required to be performed at almost all the stages of power system planning, operation and control. In this paper, two supervised learning networks namely counter propagation neural networks (CPNN) and multilayer feedforward network with back propagation algorithms are proposed to solve power flow problem under different loading/contingency conditions for computing bus voltage magnitudes and angles of the power system. The artiflcail neural networks implement a pattern mapping task. The CPNN is a network which can obtain a mapping from inputs to outputs by competitive learning and supervised learning. Extensive studies have been made by varying the network parameters of both the networks. The hidden neurons are also varied to fix the optimum architecture for the problem to be solved. Due to its fast training, the proposed CPNN will be particularly useful for power system planning studies, as a number of combinations can be tried within a small time frame. The mathematical model of power flow comprises a set of non-linear algebraic equations conventionally solved with the Newton-Raphson method. The effectiveness of the proposed CPNN based approach for solving power flow is demonstrated by computation of bus voltage magnitudes and voltage angles for different loading conditions and single line-outage contingencies in IEEE 14-bus system. Results of the both the ANN closely agrees with that obtained by fast decoupled load flow. The computation time of both the ANN is much smaller than that by fast decoupled load-flow. However, comparing the training time and suitability for online application in power systems, CPNN is best suited due to its fast learning based on Euclidean distance calculations.Diakoptic surface integral-equation formulation applied to large 2-D scattering problems
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.1345
A diakoptic surface integral-equation formulation is applied to 2-D transversal magnetic (TM) scattering problems. The diakoptic formulation is based on the equivalence (Huygens') principle. The aim of the diakoptic formulation is to reduce the CPU time needed for the electromagnetic analysis and the memory needed for the data storage without compromising the final results. The proposed diakoptic formulation is illustrated on two examples of 2-D TM scatterers. The calculated radar cross-section (RCS), CPU time, and storage requirements are compared to those of the classic method of moments (MoM). (7 pages)On the calculation of time-domain response of antennas mounted on large platforms
http://dl-live.theiet.org/content/conferences/10.1049/ic.2007.0844
We present an efficient and accurate approach for calculating time-domain responses of antennas mounted on electrically large platforms, such as airplanes, spacecrafts, ships, tanks, etc. The approach is based on the proficient frequency-domain analysis coupled with the inverse Fourier transform, in order to obtain time-domain responses. For the basic frequency-domain analysis we use method of moments (MoM) with higher-order basis functions and Galerkin testing procedure [3], incorporated in the WIPL-D Pro software package. If the analyzed antenna is mounted on the large platform the rigorous MoM analysis needs a lot of computer resources. However, the number of unknown coefficients for the approximation of the current distribution, needed in the frequency analysis, can be drastically reduced without loosing the accuracy significantly [4]. We utilize that fact for the calculation of time-domain responses. (6 pages)Feature extraction in auditory brainstem responses using wavelet decomposition on a moving window of waveform data
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060457
The auditory brainstem response is a waveform present in a subject's EEG in response to a heard stimulus. The waveforms are hidden deep within the EEG and a significant body of work has been devoted to the enhancement and automated classification of these responses. This paper investigates the use of features extracted from the wavelet domain to assist in the classification of the ABR waveform. Initially, strong responses were classified without error by combining power features from the time and wavelet domain and applying a negative weighting to test cases where the presence of an artefact was suspected. The remaining ABR waveforms were passed to a second stage of classification. Cross-correlation features were extracted from repeat recordings using wavelet decomposition performed on a moving window of data within the post stimulus waveform. By separating different frequency levels within the decomposition a more representative post stimulus section of the waveform was analysed. When compared with expert opinion, the lower level responses with repeat recordings were classified to an accuracy of 76.4%.Modal analysis and DC damping controller design of AC/DC power system with multi-infeed HVDC
http://dl-live.theiet.org/content/conferences/10.1049/cp_20062006
Complicated grid structure and multiple oscillatory modes, making DC damping controller design difficult, are the features of an AC/DC power system with multiple HVDC links. This paper presents a typical AC/DC power system with three HVDC links for the study. The study power system's performances are investigated using modal analysis and nonlinear time domain simulations. Frequency differences across the HVDC links are selected as the input signals into the DC damping controllers. Comparing with active power deviations on ac tie lines, the frequency differences have more advantages in phase compensation design. The performance of each damping controller is evaluated separately, and the simultaneous effects of the multiple controllers are also considered. In the rear of this paper, transient simulations of the system with damping controls are carried out, and the simulation results demonstrate that the DC damping controllers effectively increase the study system's damping. (6 pages)Analysis of surface electromyography signals using continuous wavelet transform for feature extraction
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060353
A number of digital signal processing techniques are being applied to surface electromyography (SEMG) signals for classification using feature extraction. Traditional analysis methods such as fast Fourier transform (FFT) could not be used alone because muscle diagnosis requires time-based information. Continuous wavelet transform (CWT) was selected for extracting efficient features of the SEMG signals in this research. CWT includes time-based information as well as scales, which can be converted to frequencies, making muscle diagnosis easier. CWT produces a scalogram plot along with its corresponding time-frequency based spectrum plot. Using the extracted features of the dominant frequencies of the wavelet transform and the related scales, we were able to train and validate an artificial neural network (ANN) for signal classification. (4 pages)Image denoising using wavelet embedded anisotropic diffusion (WEAD)
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060597
In this paper a PDE based hybrid method for image denoising is introduced. The method is a bi-stage filter with anisotropic diffusion followed by wavelet based Bayesian shrinkage. Here efficient denoising is achieved by reducing the convergence time of anisotropic diffusion. As the convergence time decreases, image blurring can be restricted and produces a better denoised image than anisotropic or wavelet based methods. Experimental results based on PSNR, SSIM and edge analysis shows excellent performance of the proposed method.An adaptive HVDC supplementary damping controller based on reinforcement learning
http://dl-live.theiet.org/content/conferences/10.1049/cp_20062050
This paper presents an adaptive supplementary damping controller on HVDC based on reinforcement learning algorithm, the controller adopted adaptive heuristic adaptive, which makes the controller could overcome the dependence of traditional damping controller on mathematical model of power system, and meanwhile, the parameter of the controller are updated by the adaptive heuristic assessment algorithm according to the reinforcement signal from power system. The simulations results shows that this supplementary controller can damp the oscillation of the power system for a class of operation and fault and it has a high learning rate, which is important to online learning, so the secure and stable operation of power system can be improved to a certain extent. (5 pages)Equivalent machine transient energy function method for transient stability assessment
http://dl-live.theiet.org/content/conferences/10.1049/cp_20061979
Two problems shall be solved when hybrid method is applied for on-line transient stability assessment for large-scale power grid: one is how to determine whether system is stable or not from large amounts of trajectory information output by time domain simulation; the other is how to figure out transient energy margin along fault trajectory. Enlightened by experiences formed in long-time running, it is proposed in this paper that we can assess system stability by transient energy reflected by relative moving of machines. Concepts of equivalent machine and equivalent machine transient energy function method are proposed based on single machine transient energy function method. Simulation results illustrate the validity of the method. It suggests that we can determine whether system is stable or not and obtain system transient energy margin from relative moving trajectory between critical machine and reference machine. (6 pages)Kinematics analysis of active reflector supporting mechanism for FAST
http://dl-live.theiet.org/content/conferences/10.1049/cp_20061084
In the application of active reflector units supporting mechanism for a large spherical radio telescope (five-hundred meter aperture spherical radio telescope: FAST), a spatial three-degree-of-freedom (DOF) parallel mechanism combining two degrees rotation and one degree translation is investigated. In this paper, the mechanism is described in detail and its inverse kinematics solutions are derived. The parasitic motion of this mechanism is analyzed, and the relationships between the parasitic motions and independent motions of the mechanism are illustrated, followed by the Jacobian matrix of the velocity equation. The distribution of conditioning index on the workspace of the mechanism is obtained. And the workspace of the mechanism is numerically generated. The analysis results prove that the parasitic motion is neglectable compared to the independent motion in this application and the mechanism can be used as the supporting mechanism of spherical radio telescope.Application of center manifold theory on analysis of voltage stability of single-machine infinite system with dynamic loads
http://dl-live.theiet.org/content/conferences/10.1049/cp_20062098
The paper researched the model of single-machine infinite system with dynamic loads that based on the voltage collapse model of center manifold and analyzed the voltage stability as the load power increasing. In the model, the generator was regarded as the non-salient pole machine and its mathematic model was the classical third-order model. The loads were composed of static loads, dynamic loads and PQ loads. The paper made use of the center manifold theory to simplify the original differential equation sets and compared the simulation results of the original and the simplified system. The results presented that the lower dimensional system was equivalent to the original system in the neighborhood of the saddle node bifurcation (SNB) point and the reduction dimension method could be applied to study the structure of the manifold at the non-hyperbola equilibrium point. (5 pages)The tool paths generation approach based on level-set methods in die-cavities NC machining
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060857
A new method based on level-set methods for tool path generation in die-cavities machining is represented in this paper, which can resolve most topological problems in die-cavities pocket milling, and can enhance the efficiency and quality of the machining. For the tool paths are sets of offset curves between the cavities outline and the internal islands, this approach adopted the principle of level-set methods and treated with tool paths in one milling layer as shape-varying wave front curves. This method translated the problem how to generate offset tool paths into a problem to solve the expression of zero sets in different time of a 3D surface, which is called as level-set function. Compare with other conventional methods, this method overcame the shortages such as path singularities, self-interactions and complexity of implement ways, and generated tool paths naturally and stably by its inherent feature inherited from the level-set Methods. The illustrative example of compute implementation in this paper has proved the effectivity and succinctness of this method sufficiently. Therefore, as a feasible way, this method is suitable for generating tool paths for die-cavities NC machining.Estimating boundaries of primary heart sounds for diagnosing heart valve disorders
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060354
Estimation of the boundaries of primary heart sounds (S1 & S2) aids the characterization of murmurs present in the heart sound cycle for diagnosing heart valve disorders. The work presents an effective boundary estimation algorithm. Extensive incorporation of biomedical domain features facilitates the development of a computationally efficient algorithm using fundamental time-domain signal analysis techniques. The accuracy of algorithm is established over complex heart sound patterns pertaining to various heart valve disorders. (4 pages)Multiresolution S-transform analysis of somatosensory evoked potentials for intraoperative monitoring
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060351
This paper proposes the application of a novel time-frequency analysis (TFA) technique, the S-transform (ST) on spinal somatosensory evoked potentials (SSEP). Variations of ST were used to analyze SSEP signals for monitoring the integrity of spinal cord during spinal surgery. A graphical user interface (GUI) was developed in MATLAB® to analyze SSEP signals using a few types of ST. Analysis had been carried out to compare the usefulness of generalized S-transform (GST), complex S-transform (CST) and hyperbolic S-transform (HST) with short-time Fourier transform (STFT). Time-frequency features were extracted from the ST plot of SSEP signals to determine the usefulness of the proposed techniques. It is observed from the analysis that GST, CST and HST indeed provide better results compared to STFT. (4 pages)Predicting intention and direction of wrist movement from EEG
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060383
Brain-computer interfaces (BCI) offer potential for individuals with a variety of movement and sensory disabilities to control their environment, communicate and control mobility aids. However, the key to BCI usability rests in being able to extract relevant time varying signals that can be classified into usable commands. In this study we report on the results of experiments investigating the ability to classify scalp EEG signals on the basis of a users intention to move (and imaging to move) their wrist in different directions. EEG activity recorded from the scalp overlying the sensorimotor cortex was examined in the frequency domain to identify pre-movement patterns of synchronization and desynchronization. Based on this, a further classification of the EEG epochs was performed based on principal component analysis for feature extraction and Euclidean distance for intention classification. Classification success rates between 70-90% have been obtained using this relatively simple method suggesting that classification of pre-movement potentials can realistically be achieved in real time. (4 pages)Automatic detection of epileptic seizure using time-frequency distributions
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060378
The aim of this work is to introduce a new method based on time frequency distribution for classifying the EEG signals. Some parameters are extracted using time-frequency distribution as inputs to a feed-forward backpropagation neural networks (FBNN). The proposed method had better results with 98.25% accuracy compared to previously studied methods such as wavelet transform, entropy, logistic regression and Lyapunov exponent. (4 pages)Voltage stability of an HVDC system for a large offshore wind farm with DFIGs
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060031
This paper analyzes the voltage stability of a control scheme proposed for a large offshore wind farm of DFIGs and linked to the grid using an HVDC system. HVDC rectifier control is set to regulate the local frequency and deliver the real power that is captured by the generator. The generator reactive power is controlled by keeping the stator flux linkage constant. Comparison is made with a more conventional way in which the DFIG reactive power is set explicitly. The study illustrates the reactive power-voltage (Q-V) characteristic of the HVDC system and the requirement on DFIG reactive power or excitation control in order to maintain the voltage stability of the overall system. Analysis based on the dQ/dV criterion is verified by time domain simulation. Effect of the bandwidth of generator control is evaluated.Classification of ECG arrhythmias based on statistical and time-frequency features
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060376
In this paper a new approach to accurately classify ECG arrhythmias through a combination of the wavelet transform and artificial neural network is presented. Three kinds of features in a very computationally efficient manner are computed as follows: 1-Joint time-frequency features (discrete wavelet transform coefficients). 2-Time domain features (R-R intervals). 3-Statistical feature (form factor). Using these features, the limitations of other methods in classifying multiple kinds of arrhythmia with high accuracy for all of them at once are overcome. Finally, a cascade classifier including two ANNs has been designed. Considering the whole MIT-BIH arrhythmia database, 10 kinds of arrhythmia were classified. The overall accuracy of classification of the proposed approach is above 90%. (4 pages)Power quality identification based on s-transform and RBF neural network
http://dl-live.theiet.org/content/conferences/10.1049/cp_20062125
This paper proposes a new power quality (PQ) disturbances identification method based on S-transform time-frequency analysis and RBF network. The proposed technique consists of time-frequency analysis, feature extraction, and pattern classification. Though there are several time-frequency analysis methods existing in the literature, this paper uses S-transform to obtain the time-frequency characteristics of PQ events because of its superior performance under noise. Using the time-frequency characteristics, a set of features is extracted for identification of power quality disturbances. Finally, a RBF network is developed for classification of the power quality disturbances. The proposed method is simple and reach 97.5% identification correct ratio even under high signal to noise ratio for those most important disturbances in power system. (6 pages)Efficient control for network congestion
http://dl-live.theiet.org/content/conferences/10.1049/cp_20061310
Efficient congestion control should fully use the bandwidth for a large network with many routers and terminals. This paper develops a congestion control algorithm based differential equations' fluid model. The proposed control algorithm considers that under many flows, the stability of the fluid model ensures the convergence of the average rate to its equilibrium point, may impose excessive restriction of our choice of AQM parameters. Simulations verify the proposed control design can avoid of the congestion problem of bottleneck network. Under many flows with large capacity, simulations have shown that the AQM system utilization still approaches to full utilization, while the buffer size on the order of bandwidth-delay product is necessary for the stability of the fluid model with full utilization. (4 pages)Cascade continuous-time sigma-delta modulators with reduced number of analog components application to VDSL
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050163
This paper describes new cascaded continuous-time ΣΔ modulators intended to cope with VDSL specifications. These modulators have been synthesized using a new methodology that is based on the direct synthesis of the whole cascaded architecture in the continuous-time domain instead of using a discrete-to-continuous time transformation as has been done in previous approaches. This method allows to efficiently place the zeros/poles of the loop-filter transfer function and to reduce the number of analog components, thus leading to more efficient topologies in terms of circuitry complexity, power consumption and robustness with respect to circuit parasitics.Comparison of time-frequency distribution techniques using multi-component non-stationary test signals
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050322
In the course of this study, time-frequency energy distribution techniques have been compared using a series of test signals that have very specific profiles in the time frequency domain. The techniques, which are going to be examined are the short time Fourier transform, wavelet transform, Wigner-Ville transform, pseudo Wigner-Ville distribution, Rihaczek and Margenau Hill distributions, smoothed pseudo Wigner-Ville distribution, Choi-Williams distribution, Born-Jordan distribution, Zhao Atlas Marks distribution and Baranuik Jones optimal radially Gaussian kernel method. These techniques are all a subset of the Cohen class of energy distributions. In order to examine these techniques, three test signals were used. The first signal is two chirp signals, one increasing in frequency and the other decreasing in frequency. This signal ideally should have a distinctive "X" shape in the time-frequency domain. The second signal is an amplitude-modulated signal with two added impulses. This ideally should have an "U" shape in the time frequency domain. The final signal is the linear sum of the two signals as explained above. An ideal time frequency representation for the three signals was generated and a comparison between the techniques was taken against these ideal signals using percentile root mean squared differences. These signals are among the most difficult signals to resolve in the time-frequency domain.Transient analysis of DFIG wind turbines in multi-machine networks
http://dl-live.theiet.org/content/conferences/10.1049/cp_20051265
This paper presents the transient analysis of doubly fed induction generator (DFIG) wind turbines in multiple machine networks. Computer simulations were carried out using IPSA software. The performance of DFIG wind turbines and controllers was presented using three different network configurations including a large wind farm connected to a multimachine system. Simulation results illustrated the consequences of modeling the main system by an infinite bus model or by an equivalent loaded synchronous generator. It was observed that in this case the control system design and tuning plays a fundamental role in the dynamic characteristics of the wind farm and its interaction with the power network. (5 pages)In-field verification of the real-time distribution state estimation
http://dl-live.theiet.org/content/conferences/10.1049/cp_20051129
This paper briefly describes the idea of DSE - a fast, robust and very efficient distribution real-time state estimator Its speed is a result of the reduction of all parts of the network which are not observable (remotely monitored) in the network mathematical model. It is robust since it is tailored to be applicable in any distribution network - from one where only historical data are available, until one that is fully remotely controlled. In-field proof of its efficiency was the main aspect of this paper. The presented results are only a small, but representative sample of the large complex of measurements and DSE running, performed in the last few years, especially in autumn 2004. This sample stresses the main conclusions derived from the named large complex of measurements. These are: 1-the significance of historical and real-time (telemetered) data is not only stressed, but also their relative weights are practically stated; 2-the estimation results are much better as the estimated network elements supply higher number of loads; therefore, the estimation of losses in these elements is better; 3-the estimation of voltages is very good; therefore, the centralized voltage control could be performed very efficiently. Finally, the paper proves that the real-time state estimation in distribution networks is not only possible, but also it is sufficiently reliable and accurate for the purpose of real-time managing of distribution networks. DSE is designed in such a way that its effectiveness is in direct proportion with the size of the observable part of the network and the quality of the historical data. (4 pages)