New Publications are available for Algebra
http://dl-live.theiet.org
New Publications are available now online for this publication.
Please follow the links to view the publication.Research on uncertainty of bounce time for electromagnetic relay and its application in operating reliability estimation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0648
The paper analyzes the uncertainty of bounce time of contacts for relay. It changes the bounce time series into symbolic series according to the threshold function given in the paper. By means of the coding symbolic series and probability statistical analysis, we propose a concept named series entropy, which is a suitable eigenvalue for temporal schema and helps to find the time-change law of uncertainty of bounce time series. The analysis indicates that series entropy of bounce time for bad contacts descend as time goes on. The law can be used to predict the operating reliability.Study on acquiring key performance parameters and comprehensive performance degradation model of relays
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0666
Study on the degradation performance mode has great significance for the life prediction of the relays. The contact resistance, pull-in time and other parameters (e.g., temperature rise) reflect the strengths and weaknesses of the relays from different extent. In order to study the performance degradation rules of the relays, we should process lots of sequence information that contains so many parameters and sampling points. We have to compress masses of data related. First of all, use a couple of ways to select the sequence information with the neural network such as selecting the sample points continuously, every two points, every three points and so on, so that we can determine which method to choose by comparing the errors we get. And then we can identify the rows of the sequence information matrix. To extract the key performance parameters, we should deal with the column vectors of the sequence information matrix with PCA (i.e., reducing the dimension of the matrix). And construct value function to acquire the characteristic quantity which can describe the comprehensive performance reliability of the relays. Finally we can get the comprehensive performance degradation model of the relays.WR-3 band butler matrix design using SU-8 photo-resist technology
http://dl-live.theiet.org/content/conferences/10.1049/ic.2012.0061
A design of WR-3 band 2×2 Butler Matrix feeding a 2-element slotted waveguide antenna array is presented in this paper. The whole design is based on an SU-8 multi-layer structure, which is expected to be fabricated by metal-coated SU-8 thick resist technology [1]. Each layer of the SU-8 wafer has a thickness of 0.432mm, which matches the narrow-wall height of a WR-3 (220-325GHz) waveguide. To examine the performance of the proposed Matrix, prior to adding antennas, a simulation on the 90 degree resonator based hybrid coupler was carried out using the CST Microwave Studio [2]. The simulation results agree well with the theoretical predictions, validating the proposed design.Digital image ownership verification based on spatial correlation of colors
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0448
In this paper, a spatial domain digital image copyright protection scheme based on Visual Cryptography (VC) and Spatial Correlation of Colors (SCC) is proposed. A binary feature matrix, extracted from the spatial correlation of host image, is used to split the watermark into two noisy binary images called shares. One of them is generated during watermark embedding phase and is registered with a trusted third party. The other is extracted during watermark extraction phase. Both these shares are combined to recover hidden watermark. When compared to the related works, the proposed scheme reduces the probability of false positives; reduces the size of shares and improves the quality of extracted watermark. Experimental results prove that the scheme is also robust to wide range of attacks. (5 pages)A novel transmission line pilot protection principle based on current model recognition
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0115
Due to the distributed capacitance, the conventional current differential protection has unsatisfying performance. Considering matrix pencil algorithm can accurately analyze the composition of fault transient currents, a novel pilot protection principle using only current data is proposed in this paper to solve the above problem. This principle adopts model recognition concept. Firstly, the theoretical expression for external fault is derived which describes the ratio between the sum and difference of two terminal fault component currents, and the expression is defined as the standard model. Then the model error function is established while the function measures the extent to which actual fault data accord with the standard model. When an external fault occurs, fault data correspond with the standard model and the model error equals zero. When an internal fault occurs, fault data do not correspond with the standard model and the model error is greater than zero. Therefore, external fault and internal fault are distinguished. This new principle is immune to the distributed capacitance and has high reliability without using voltage data. Moreover, the principle possesses fast operation speed and high sensitivity. Electromagnetic transient program (EMTP) simulation results verify the effectiveness of the proposed principle. (6 pages)A novel transmission line pilot protection principle based on frequency-domain model identification of distributed parameter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0125
This paper proposes a novel transmission line protection scheme based on frequency-domain model identification method with distributed parameter. Integrated impedance is defined by voltages and currents of two end terminals of transmission line. By analyzing the frequency-domain expressions of integrated impedance in internal and external fault states, the amplitude-frequency characteristics of the integrated impedance are discussed. The integrated impedance in internal fault state shows system impedance characteristic and the integrated impedance in external fault state shows the line distributed capacitive characteristic. The frequency-domain model errors are defined as unbalanced currents respectively in order to identify the internal and external faults. Matrix pencil algorithm is used to calculate the phasors in different frequencies in the proposed scheme. Protection criterions are designed and some tests are performed. The simulation results show that the proposed schemes can detect internal fault quickly and reliably. Furthermore, the influences from capacitive currents and transition resistances can be avoided in the proposed protection scheme. (6 pages)Decentralized coordinated robust controller design for multimachine power system based on multi-agent system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0084
A decentralized coordinated control is researched based on multi-agent structure for transient stability improvement of large-scale power system in this paper. First, a multi-agent system (MAS) model is structured based on the wide-area measurement system (WAMS), which consists of both upper and lower level agents. The upper level coordinated agents are mainly responsible for coordinating and controlling the lower level agents via sending coordinated control signals into local decentralized control loops in order to damp lower frequency oscillations between regions. And the main function of lower level agents is to continuously regulate generator unit through excitation controller to overcome small disturbances. Then, the focal task of this paper is to design a decentralized coordinated controller based on the MAS model. To eliminate the nonlinearities and interconnections of multimachine models, a direct feedback linearization (DFL) compensator is designed through the decentralized excitation control loop. Besides, taking consideration of the effects of uncertainty introduced by transient process, the H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">∞</sub> robust control method integrating with linear matrix inequality (LMI) technology is used to seek the solutions of the decentralized coordinated controller. Finally, simulation demonstrates that the MAS based decentralized coordinated robust controller has better transient stabilization performance than the conventional PSS. (6 pages)Transmission wave modelling and calibration in cavity of open-ended rectangular waveguide
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0204
The accuracy of the open-ended waveguide technique for the determination of reflection coefficient of a sample is strongly affected by stray capacitance and conductance at the aperture end of the waveguide. The commercial waveguide calibration kit is quite expensive. In this paper, we apply phase extension technique for determination of reflection coefficient of a sample using a HP 8720 vector network analyzer where the sample reference plane did not coincide with the calibration plane.Coupling matrix synthesis of triple-passband filters using optimisation
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0197
In this paper a coupling matrix synthesis procedure based on a combination of global and local optimisations has been presented. The coupling matrices of two high-order triple-band filters have been synthesized to demonstrate its applicability for cross-coupled filters with complex topologies and frequency responses. Convergence of the optimisation is fast and no initial values for control parameters are required. This technique can be used to synthesize many other multiple-passband filters. These coupling matrices can be used to produce practical filters with any resonator.Robust PSD features for ion-channel signals
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0154
Ion-channel sensors which mimic naturally occurring pore-forming proteins can be used to detect small metal ions and organic molecules. A chamber with a lipid bilayer hosting ion-channels produced by protein insertion constitutes such a sensor. Each analyte produces a characteristic signal pattern during its migration from one section of the chamber to another through the ion-channels. A four chamber ion-channel sensor array is built for accurate analyte detection. The power distribution information in the transform domain has been successfully used as discriminatory features for each chamber signal. However, these features are not robust to noise and hence result in a reduced classification performance. In this paper, we pose the stabilization of PSD features extracted from noisy segments as a matrix completion problem. Matrix completion with a low rank assumption provides the stabilized features. We demonstrate using a synthetic experiment that the proposed setup achieves improved classification performance in comparison to using the features directly. Furthermore, performing analyte detection in real ion-channel data, using the proposed robust features, provides reduction in false alarm rates. (5 pages)Wyner-Ziv coding for distributed compressive sensing
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0141
Distributed compressive sensing (CS) is emerging as a powerful technique of distributed signal processing in various applications such as sensor networks due to its capability of simultaneous sensing and compression. However, since distributed CS is an analog technique, a fundamental open question is to find the best source coding scheme for the distributed CS samples. This paper applies nested-lattice Wyner-Ziv coding to the CS data by exploiting the correlation among the CS samples at different sensors. The proposed coder consists of CS with Toeplitz/circulant sensing matrices and practical Wyner-Ziv coding. Simulation results shows this is a fast, energy-saving system and recovers good quality image sources with low distortion and high SNR. (5 pages)Helically corrugated waveguide microwave pulse compression experiments
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0203
A high microwave pulse compressor based on a large diameter 5-fold helical waveguide structure was studied. The eigenwave dispersion was calculated using numerical and analytical techniques and compared with experimental measurements. The results of 5-fold helically corrugated waveguide microwave pulse compression experiments will be presented.Performance analysis of the data subtraction based robust beamfromer
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0158
Performance of the sample matrix inversion (SMI) beamformer degrades severely due to the finite sample size effect and the arrival angle mismatch problem. A simple technique to provide robustness to the conventional SMI beamformer is to block the desired signal from the received data before calculating the beamformer's weight vector, which leads to the data subtraction based SMI (S-SMI) beamformer. In this paper,d we analyse the performance of the S-SMI beamformer in term of its output signal-to-interference-plus-noise ratio (SINR) in the presence of both finite sample size effect and arrival angle mismatch problem. (5 pages)Medical image security using LSB and chaotic logistic map
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0086
In this modem era, many researchers have been concentrating more on using the field of chaos and its applications for their research. Particularly, medical image encryption and decryption using chaotic signals are proposed frequently for medical image cryptography and steganography. In this article, the patient medical details in text form and medical image of the organ in pictorial form are encrypted and decrypted using two different set of algorithms. One of the advantages of this method is its security, which is provided by the chaotic signal.An improved method using kinematic features for action recognition
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0766
Human action recognition is a challenge problem in computer vision. In this paper, we propose an improved approach using kinematic features for action recognition. In this approach, we find the area that relates to action by a simple method, and select eight discriminative features derived from optical flow field to describe the dynamics of the field. The covariance matrix of the feature vectors is used to fuse the features and to serve as the feature descriptor. Multi-class SVM classifiers are then employed for action classification. Experiments are carried out on public datasets. We obtain a recognition rate of 97.66% SEG-ACA and 98.2% SEQ-ACA on KTH dataset, and 98.89% SEQ-ACA and 93.83% SEG-ACA on WEIZMANN dataset with leave-one-out test.Electromagnetic source reconstruction by reversed-TLM method
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0020
Classical methods for source synthesis are iterative, time consuming and not always adapted to the desired problem. In this paper we present a new method of electromagnetic source synthesis based on the time reversal technique. This approach employs the Reversed-TLM method and permits the reconstruction of an unknown source distribution, from its electromagnetic far-field radiation. Point-like source reconstruction results show that by using this method, the "classical" half-wavelength resolution limit is overcome.Sparse time-variant MIMO channel in high speed mobile scenario
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0975
A sparse Multiple-input Multiple-output (MIMO) channel model in high-speed railway scenario is obtained in this paper using the Virtual Channel Representation (VCR). The MIMO time-variant channel is investigated in receive, transmit antenna and Doppler domains. And the sparse channel analysis algorithm is combined with the Higher-Order Singular Value Decomposition (HOSVD) to study the spatial characteristics of H(t).A modified ESPRIT algorithm for signal DOA estimation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0647
We propose a new algorithm to estimate the 2-D direction of arrival (DOA) of narrowband sources lying in the far field of the array. The algorithm requires no reference signal, which consists of two stage processes. The algorithm of the first stage using the method of ESPRIT acquires data. At the second stage, the method using the space-time DOA matrix method to processing the data. The method transfers the observed data from space domain to 2-D space-time domain by exploiting the cross-correlation of the array outputs. Simulation results show a good improvement in processor performance.A mode matching analysis of rectangular dielectric discontinuities in metal waveguides applicable to characterisation of liquids
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0022
In this paper we present a generalised scattering matrix approach using mode matching to analyse a generic case of a rectangular dielectric sample and sample holder partially filling a metal waveguide; as encountered in liquid measurements. The results for both samples having real and complex permittivity values, for varying sample thickness are presented and compared to that obtained by a commercial finite element method software.Regularized neighborhood boundary discriminant analysis for facial expression recognition
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0999
In this paper, we propose an approach which named regularized neighborhood boundary discriminant analysis for facial expression recognition. Our algorithm is based on the linear boundary discriminant analysis (LBDA), which aims to find a optimal projection in order to enhance the ability of classification. A regularized method was executed to remove the singularity of within-class metric matrix. Experiments on JAFEE facial expression database and Cohn-Kanade database show that our proposed method can get better performance than some other methods, such as linear discriminant analysis (LDA), local fisher discriminant analysis (LFDA) and linear boundary discriminant analysis (LBDA).A dynamic cell selection scheme based on multi-object for COMP DL IN LTE-A
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0668
As a key technique in Long Term Evolution Advanced (LTE-A) system, Coordinated multi point transmission/reception (CoMP) can mitigate the inter-cell interference, and improve both average and cell-edge throughput. Choosing the proper cooperating cells for CoMP operation is a very important problem in CoMP. In this paper, factors which affect the performance of CoMP are analysed and a dynamic cell selection scheme based on multi-objective decision-making method are proposed. A multi-object decision matrix is created in this scheme to evaluate the effect of different factors on CoMP performance in order to choose the best cooperating cells. The system level simulation results show that our proposed dynamic cell selection scheme, compared with other CoMP schemes, can bring more performance gains.On the dynamics of an hydropower generator subjected to unbalanced magnetic pull
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0032
Eccentricity leading to unbalanced magnetic pull (UMP) in electrical machines is a significant concern in industry. The UMP is known to be composed of two components: A radial component and a tangential one. Models that are used in industry currently tend to include the radial component alone. In this paper, a Jeffcott rotor model together with a new UMP model that incorporates both radial and tangential UMP constituents is studied for an industrial hydropower generator. Characterising the UMP as springs permits the model to inherit UMP stiffness contribution. Interesting dynamics are observed with the new model for a wide range of external forcing frequencies. It is shown firstly that the new UMP model is sensitive to forcing frequency in the rotor movements. Moreover, complex dynamics in the displacements of the rotor are observed for some forcing frequencies and it is noted that the rotor does not need to be forced by frequencies above its critical speed for this less desirable motion to occur. Eigenvalue-based stability analysis is performed and shows that damping of the rotor and of the bearings are important when non-synchronous whirling of the rotor is considered. Accounting for both components of UMP is an important cornerstone in the generation of better rotor design parameters which can help to curb rotor-stator malfunction and can contribute in the design of long lasting rotors to the betterment of hydropower technology.Facial expression recognition using local binary covariance matrices
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0997
In this paper, we propose a novel local feature descriptor for facial expression recognition, referred as local binary covariance matrices (LBCM). The covariance matrix in LBCM is constructed by incorporating location, intensity and local binary features of each pixel inside a region of interest. Extensive experiments demonstrate the effectiveness of LBCM for FER, even if partial occlusion exists.A new mobile single observation passive location algorithm
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0845
According to the passive location algorithm of phase difference and Doppler frequency rate of change, an algorithm based on probability is put forward. The Taylor expansion is used to simplify the calculation, avoiding solving the complex matrix equation and error caused by unreasonably setting initial values. Simulation results show the feasibility and the correctness of the algorithm.Comparing different approaches for the numerical identification of R, L parameters of HF multi-winding transformers
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0037
In this paper, mathematically rigorous R, L circuits of high frequency multi-winding transformers are numerically extracted. Two procedures based on the Finite Element Method (FEM) are investigated. In the first one, a Cholesky decomposition is applied to the resistance and inductance matrices of the device, which are obtained using a FE model. The second approach employs the FEM as a virtual laboratory in order to perform numerically open and short-circuit tests on the transformer. The two methods are compared regarding the overall computational burden and the obtained lumped parameters, for 2D and 3D models.Enhancement of voltage stability by coordinated control of multiple FACTS controllers in multi-machine power system environments
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0328
This paper presents the implication of adding various FACTS controllers in multi-machine power system environment in coordinated control manner for enhancement of voltage stability requires an appropriate mathematical model of the power system and the FACTs controllers such as a Static Var Compensator (SVC) and Thyristor Controlled Series Capacitor (TCSC). The DAE (Differential Algebraic Equation) methodology for multi-machine system has been is used in this paper. Event tough the SVC model has been incorporated in DAE model, TCSC model has not been incorporated. So the purpose of this paper is to derive a TCSC model such that it can be incorporated in DAE model of power system. Further in a large power system there may be more than one FACTS controllers, therefore it is important to develop a combination of series and shunt FACTS controllers that can be incorporated in the DAE model in Modular fashion. The models developed have been utilized for eigen-value analysis of IEEE 9-bus 3-machine power systems. There are many commercial packages available for transient simulation and analysis of power systems. The transient simulation packages (e.g. EMTDC/PSCAD) allow incorporation of FACTS controller models. This facility is however not available in the small signal stability analysis packages. The objective of this paper is to develop a methodology to incorporate FA CTS controllers in a modular fashion to facilitate eigen-value and voltage stability analysis using MATLAB toolbox.Modelling of AC feeding systems of electric railways based on a uniform multi-conductor chain circuit topology
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0018
AC power feeding systems of electric railways can be viewed as a multi-conductor chain circuit. All electrical elements along the railway, even including the short circuits and conductor breaks, can be described as series or shunt elements. According to the chain circuit topology, the mathematical model of the whole feeding system, i.e. the admittance matrix, can be assembled conveniently by appropriately modelling each element. Considering the relatively large leakage conductance of the current return rail to the ground, multi-conductor equivalent-π circuits can be adopted for each section of the feeding system. The characteristic admittance matrix, which can be calculated by the phase-modal transformation method, is introduced for the truncation treatment at terminals of a feeding system. The proposed modelling methodology has been realised using a simulation program, which can be used to investigate a wide range of problems in electric railway feeding systems, such as the conductor current distribution, the lowest train voltage at peak time, the short circuit calculation, the rail potential distribution and the harmonic propagation. (5 pages)Processing three-channel SAR-ATI for GMTI
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0222
This paper investigates two methods for GMTI using three-channel SAR-ATI data. Motivated by previous results in the two-channel case, a deterministic method for finding an Eigendecomposition of the SAR-ATI sample covariance matrix is presented. The CFAR detection capability of each of the eight parameters of the Eigendecomposition is evaluated using measured three-channel airborne data and compared to the well- known DPCA-ATI metric. Results suggest that all moving target energy is contained in a single parameter, the largest Eigenvalue, and that for a given theoretical CFAR a lower real-world false alarm rate is achieved in comparison to DPCA-ATI. Motivated by this result ICA is then applied to the same measured three- channel data and found to both detect and distinguish two different types of moving target simultaneously present in a maritime environment. (5 pages)The circulate property of generator matrices of protograph LDPC codes
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0632
The LDPC application involves the problem: encoding complexity. Since the generator matrices are dense and with random positions of "1s", the encoder needs to store every "1" of the generator matrices by using huge chip area. To solve problem, we need to design the LDPC codes with block cyclic generator matrices. This paper reveals that the protograph LDPC codes can have lower encoding complexity under the condition of the proposed theorem that the parity check matrices of the LDPC codes are nonsingular and circulate. The circulate property of generator matrix of protograph LDPC codes can be obtained from the quasi-cyclic parity check matrix of protograph LDPC codes. Thus it can reduce the encoding complexity. We give an algorithm of protograph LDPC codes with fast encoding based on the theorem, and it verifies that protograph LDPC codes with circulate property of generator matrices can simplify encoder hardware implementation.Regularized direct linear graph embedding
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0689
Linear Graph Embedding (LGE) is the linearization of graph embedding, which could explain many of the popular dimensionality reduction algorithms such as LDA, LLE and LPP. LGE algorithms have been applied in many domains successfully; however, those algorithms need a PCA transform in advance to avoid a possible singular problem. In this paper, a regularized direct linear graph embedding algorithm is proposed by imposing Tikhonov regularizer on the objective function of LGE. Further, we extract features from the original data set directly by solving common Eigen value problem of symmetric positive semi definite matrix. Experimental results demonstrate the effectiveness and robustness of our proposed algorithm.Analysis of bistable switching and dynamic characteristics of tapered nonlinear Bragg gratings based on the time-domain transfer matrix method
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1241
Standing from the coupled mode theory, by utilizing the time-domain transfer matrix method, the bistable switching and dynamic characteristics of nonlinear Bragg gratings (NLBG) can be analyzed numerically. The results show: under steady case, various tapered factor has a different effect on the threshold switching energy and also positive and negative taper can cause the response of optical isolator in NLBG. On the other hand, with the continuous wave taken into consideration, the periodic self-pulsation may emerge easily under the dynamic conditions in NLBG. As the input power is increased to the critical intensity, the self-pulsation transform into the chaos. For the certain tapered cause, the pulsation width and the frequency of the self-pulsation will reduce with increase coupling coefficient, but the output state will transform into relaxation damped oscillation when the coupling coefficient reaches certain value.A face identification algorithm using support vector machine based on binary two dimensional principal component analysis
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0560
The two dimensional human face image (2DHFI) matrices have to be previously transformed into one dimensional image vectors row by row or column by column In the human face recognition schemes based on the one dimensional principal component analysis (1DPCA), such that the 1DPCA scheme is difficult in accurately evaluating the human face image covariance matrix and is time-consuming in determining the eigenvectors. The two dimensional principal analysis (2DPCA) schemes evaluate the HFI covariance matrix more accurately and determine the corresponding eigenvectors more efficiently than 1DPCA schemes. But, the 2DPCA schemes need many more coefficients for HFI representation than 1DPCA schemes. The binary principal component analysis (B-PCA) replaces floating-point multiplications with integer additions to significantly reduce the time consumption of the procedure. This paper utilizes the binary two dimensional principal component analysis (B2DPCA) to construct an effective human face identification system. The presented algorithm combines the scaling process, histogram equalization process, binary two dimensional principal component analysis (B2DPCA) process, and support vector machine (SVM) scheme to construct a human face identification system. The experimental results show that the presented algorithm has good efficiency for human face identification.Random matrix cooperative spectrum sensing for clustered sensors using Neyman-Pearson fusion
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1086
In this paper we use a new approach to applying the random matrix properties of cognitive radio to spectrum sensing in cognitive radio for clustered sensors, where the Secondary User (SU) sensors within a cluster are assumed to be experiencing the same noise variance and the same Primary User (PU) Signal to Noise Ratio (SNR). Pointing out some recent works on the application of Random Matrix Theory (RMT) in spectrum sensing, we suggest slight but effective changes to the previously mentioned detection strategies, which enables us to examine the idea more comprehensively from a detection theory point of view. We apply the proposed detection strategy as our spectrum sensing scheme within clusters, we then assume to have a Neyman Pearson Fusion Center where the cluster decisions are combined to obtain the final decision as our spectrum sensing. Simulation results show that with no prior knowledge about the PU signal or the noise distribution, our proposed scheme performs quite desirably.Modelling of distribution network cell based on grey-box approach
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0852
The paper presents the modeling of Distributed Network Cell (DNC) based on grey-box approach. The equivalent model of DNC comprises of a converter-connected generator and a composite load model in parallel. The detail development of the equivalent model is described in this paper. The grey-box approach is chosen based on the fact that it offers possibility to incorporate some prior knowledge about DNC structure into model development, make developed model more physically relevant and intuitive compared to black box model and potentially improve the accuracy of the model. The dynamic equivalent model is presented in the form of sixth-order nonlinear state space format and developed from the algebraic and differential equations describing assumed typical components of DNC. (6 pages)Bottom-up verification methodology for CMOS photonic linear heterogeneous system
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0144
A typical CMOS photonic circuit may comprise analog, digital and optical devices. To simulate it, a common simulation environment for electrical/optical systems is necessary. In this article, a simulation methodology for CMOS photonic heterogeneous system has been proposed. Using hardware description language, we create behavioral models for optical devices with S-matrix formalism. The challenges in model implementation have been addressed, such as large-size vector representation at model ports and complex matrix calculation. And a Verilog-AMS + VPI simulation strategy is proposed to solve the simulation issues. Finally, the proposed method is applied to bottom-up verification of a micro-ring array, and the simulation result matches well with brute force simulation, while the simulation time is largely reduced.Eigenvalue-based spectrum sensing for cognitive radio
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0184
We studied the distributions of the ratio of the extreme eigenvalues and maximum eigenvalue of the complex Wishart matrix. We derived the exact decision thresholds as a function of the desired probability of false alarm for MME and MED based cooperative spectrum sensing, which are able to handle for both correlated and uncorrelated Gaussian noise samples. The expression for the decision threshold was simplified for two receiving antenna or for the case of two user collaborative sensing. We also derived a simpler closed-form threshold function using an asymptotic distribution with equal numbers of receive antennas and signal samples, that is m = n and large n. We shown that analytical and empirical results are coincide with each other. The probability of detection performance using the proposed exact decision thresholds achieve significant performance gains compared to the performance using the asymptotic decision threshold reported in the literature, which leads to efficient spectrum usage. (25 pages)Voltage control of three-stage hybrid multilevel inverter using vector transformation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0080
Three-stage eighteen-level hybrid inverter design with novel control method are presented. The inverter consists of main high-voltage, medium-voltage and low-voltage stages connected in series from the output side. The high voltage stage is a three-phase, six-switch conventional sub-inverter. The medium and low voltage stages are made of three-level sub-inverters constructed by H-bridge units. The proposed control strategy assumes a reference input voltage vector and aims to approximate it to the nearest inverter vector. The control concept is based on holding the high voltage state as long as it is feasible to do so. The reference voltage vector has been represented in a 60°-spaced two axis coordinate system to reduce the computational effort. The concept of the staged-control has been presented, the transformed inverter vectors and their relation to the switching variables have been defined, and the implementation process has been described. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low switching losses. (6 pages)Validation of polynomial-based equidistance fish-eye models
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1700
The majority of computer vision applications assume that the camera adheres to the pin-hole camera model. However, most real optical systems will introduce some undesirable effects, rendering the assumption of the pin-hole camera model invalid. By far the most evident of these effects is radial distortion, particularly in fish-eye camera systems where the level of this distortion is relatively extreme. The aim of fish-eye distortion correction is, therefore, to transform the distorted view of fish-eye cameras to the desired rectilinear pin-hole perspective view. To perform this distortion correction, several authors have developed models of fish-eye distortion. It is the aim of this paper to examine the accuracy of several of the polynomial-based models against the equidistance mapping function, which is the most common mapping function that fish-eye lenses are designed to follow. (6 pages)Development of a novel three-axis force sensor
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1440
A novel three-axis force sensor is presented in this paper. It uses strain gauge as sensing element for the detection of force. The elastic body is a thin cylinder on which four holes are opened evenly in two levels. There are three Wheatstone bridges on the beams to detect the force in three directions. The mathematic model of the sensor is analyzed, and strength check, stiffness design and the linearity of the sensor were studied with FEA. Finally, the transmission matrix is calculated. As indicated by the calculations and experiments, this sensor is not only of high sensitivity and adequate rigidity in the three directions, but also of fairly small cross sensitivities. (4 pages)Fast method for estimation of the number of spatial signals
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0413
Estimation of the number of spatial spreaded signals is one of the key problems in array signal processing community. In this paper, we present a fast detection method via modified Hung-Turner projection (FDM-MHTP) for solving the problem. A threshold is derived exploiting the asymptotic distribution properties of the estimation errors of the sample covariance matrix. The threshold is used to detect the number of signal sources in conjunction with performing Gram-Schmidt orthogonalization onto the columns of the sample covariance matrix. Without eigenvalue decomposition, the proposed method has good detection performance and low computational complexity. Computer simulation shows the correctness and efficiency of the method. (5 pages)SFM signal parameter estimation based on discrete polynomial-phase transform
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0281
In this paper, Sine FM (SFM) signal is modelled as a high-order polynomial phase signal (PPS). By estimating its order and phase coefficients, a new parameter estimating algorithm for SFM signal is obtained, which can compute the carrier frequency, FM coefficient, and modulating frequency. Theoretical analysis and simulation results verified the efficiency of the presented algorithm, which has the advantage of computational simplicity. (4 pages)Real-time measurement method for object space 6-D information
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1441
According with the development of some special fields, the 6-D space attitude information is more useful than traditional request, such as robot trajectory control, aircraft trajectory control, complex parts assemble and so on. This paper presented a real-time measurement method to obtain the space 6-D information of moving object. Use transform matrix method, the measurement coordinate system can be transformed to the real coordinate system. By some experiments, the feasible and reliable of this real-time measurement method are verified in a Triaxial linkage simulate platform use Leica laser tracing measurement instrument. (4 pages)A new algorithm for estimating the parameters of a polynomial phase signal
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0111
This paper presents a new algorithm for estimating the parameters of a polynomial phase signal (PPS). The proposed algorithm is based on the modified version of the Wigner-Ville distribution (WVD). For a quadratic or cubic frequency modulated (FM) signal, it requires two-dimensional (2-D) maximizations. The optimal maximum likelihood algorithm, by contrast, requires a three-dimensional (3-D) or four- dimensional (4-D) maximization. The Monte-Carlo simulations are provided to illustrate the precision of the new method, its application in the instantaneous frequency (IF) estimation and time-frequency distribution are also discussed. (4 pages)Electromagnetic scattering by cylindrical arrays of circular rods
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1331
A semi-analytical and rigorous method for analyzing two-dimensional scattering of electromagnetic waves by a cylindrical array is presented. The cylindrical array is formed by parallel circular rods of infinite length which are symmetrically distributed on a circular cylindrical surface. The proposed method uses the T-matrix of a circular rod in isolation and the reflection and transmission matrices of the scattered fields expressed in terms of the cylindrical harmonic waves as the basis. The details to obtain the reflection and transmission matrices in closed form are discussed. The results are extended to the generalized reflection and transmission matrices which can be applied to the analysis of electromagnetic scattering by multilayered cylindrical arrays of circular rods.Fast jacket transform for DFT matrices based on prime factor algorithm
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.2062
Underlying the prime factor algorithm (PFA) employed Chinese remainder theorem (CRT), one-dimensional DFT can be mapped to the true two-dimensional DFT avoid twiddle factors. Enlighten by the idea of fast Jacket transform, a simple construction for large size DFT matrices is proposed. Based on the multi-dimensional index mapping extended from two-dimensional case, a general approach to decompose multi-dimensional DFT matrices is described in simple manner. The proposed algorithms are presented for simplicity and clarity for it only minimally related to sparse matrices. The results indicate the presented fast algorithms compare favourably with direct computation.Single channel pulse train radar signal separation using algebraic method
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0285
In the complex radio environment, single sensor may receive a number of mixed time-frequency overlapping radar signals. Considering the pulse train form of these signals, this paper achieves separation of fixed pulse repetition interval signals using their periodicities, and proposes the separation method of variational pulse repetition interval signals using their algebraic properties. Both approaches are based on the linear equations construction and solution without requirement of intra-pulse information of the source signals, and applicable under the situation that the source signals are time-frequency overlapping. The simulation results confirm the validity of their performance. (4 pages)Impact of CSI latency on HF multi-carrier communications for delay-sensitive applications
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0068
Multi-carrier modulations are widely used in HF communications, and particularly OFDM. Delay-sensitive applications can make use of spreading schemes such as OFDM-CDM in order to cope with deep nulls in the channel. If CSI is known at transmitter, it is possible to improve performance using a bit-loading algorithm for OFDM and channel matrix SVD decomposition for OFDM-CDM. If a source of non-ideality in CSI due to latency is taken into consideration, it is shown how performance decreases. A receiver-side technique is applied to OFDM-CDM communications to compensate for delay-incurred matrices mismatch.Research on image plane of bistatic ISAR
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0225
This work mainly discusses the image plane of the Bistatic ISAR. The image plane is modeled by two different methods separately. One is modeling the image plane according to the bistatic SAR image plane; the other is to model the plane by target rotation vector analysis. The modeling process is presented in detail. Both the models are reasonable, but are different to each other. They are then testified by applying them to interpret the bistatic turntable model, and to predict the possible imaging result. The turntable imaging simulations perfectly match the predictions of the second model, which is built by target rotation vector analysis. Further simulations of moving point-scatter bistatic imaging also indicate the validity of the second model. The deficiency of the first model is also discussed. (6 pages)Coincidence of the Rao test, Wald test, and GLRT of MIMO radar in gaussian clutter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0387
This paper deals with the problem of detecting signal with MIMO radar in correlated Gaussian clutter with known covariance matrix. The general MIMO model, with widely separated sub-arrays and co-located antennas at each sub-array, is adopted. It is proved that the Rao test and the Wald test coincide with generalized likelihood ratio test (GLRT). (4 pages)Preconditioned adaptive integral method for the analysis of planar microstrip structures
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1366
Adaptive integral method based on far-field expansion is introduced to speed up the analysis of the planar microstrip structure. The auxiliary basis functions are constructed as superposition of point-like current elements located on rectangular grids which reproduce the same far field as generated from the original basis functions. Then it is able to employ the fast Fourier transform technique to speed up the matrix vector multiplication required by the iterative solver. The resultant linear systems are then preconditioned by the symmetric successive over relaxation technique to further accelerate iteration. Compared to the previous scheme, the proposed algorithm makes a reduction in both the computational complexity and the storage requirement to attain the same precision.