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Theoretical analysis, numerical verification and geometrical representation of new three-step DTZD algorithm for time-varying nonlinear equations solving

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NEUROCOMPUTING 2016年 214卷 516-526页

作者： Guo, Dongsheng Nie, Zhuoyun Yan, Laicheng Huaqiao Univ Coll Informat Sci & Engn Xiamen 361021 Peoples R China

To solve time-varying nonlinear equations, Zhang et al. have developed a one-step discrete-time Zhang dynamics (DTZD) algorithm with O(tau(2)) error pattern, where tau denotes the sampling gap. In this paper, by exploiting the Taylor-type difference rule, a new three-step DTZD algorithm with O(tau(3)) error pattern is proposed and investigated for time-varying nonlinear equations solving. Note that such an algorithm can achieve better computational performance than the one-step DTZD algorithm. As for the proposed three step DTZD algorithm, theoretical results are given to show its excellent computational property. Comparative numerical results further substantiate the efficacy and superiority of the proposed three-step DTZD algorithm for solving time-varying nonlinear equations, as compared with the one-step DTZD algorithm. Besides, the geometric representation of the proposed three-step DTZD algorithm is provided for time-varying nonlinear equations solving. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Discrete-time Zhang dynamics three-step algorithm Geometric representation Theoretical analysis Time-varying nonlinear equations

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Hammerstein system identification with quantised inputs and quantised output observations

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IET CONTROL THEORY AND APPLICATIONS 2017年第4期11卷 593-599页

作者： Guo, Jin Liu, Haitao Univ Sci & Technol Beijing Sch Automat & Elect Engn Beijing 100083 Peoples R China

This study focuses on a discrete-time Hammerstein system to investigate the identification with quantised inputs and quantised output observations. After the discussion of the system identifiability and by parameterising the static non-linear function, a three-step algorithm is proposed to estimate the unknown parameters for the identifiable system. The strong convergence and the mean-square convergence rate of the algorithm are established. It is shown that the asymptotic efficiency can be achieved in terms of the Cramer-Rao lower bound by selecting a suitable transformation matrix. A numerical simulation is given to demonstrate the effectiveness of the algorithm.

关键词： discrete time systems nonlinear control systems convergence of numerical methods matrix algebra parameter estimation quantised inputs quantised output discrete-time Hammerstein system identification system identifiability static nonlinear function parameterisation three-step algorithm unknown parameter estimation identifiable system mean-square convergence rate asymptotic efficiency Cramer-Rao lower bound transformation matrix

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DYNAMIC MIXTURES OF FACTOR ANALYZERS TO CHARACTERIZE MULTIVARIATE AIR POLLUTANT EXPOSURES

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ANNALS OF APPLIED STATISTICS 2017年第3期11卷 1617-1648页

作者： Maruotti, Antonello Bulla, Jan Lagona, Francesco Picone, Marco Martella, Francesca Univ Southampton Ctr Innovat & Leadership Hlth Sci Univ Rd Southampton SO17 1BJ Hants England Libera Univ Maria Ss Assunta Dipartimento Sci Econ Polit & Lingue Moderne Via Pompeo Magno 22 I-00192 Rome Italy Univ Bergen Dept Math Allegaten 41 N-5007 Bergen Norway Univ Rome Tre Dipartimento Sci Polit Via Grabriello Chiabrera 199 I-00145 Rome Italy Inst Environm Protect & Res ISPRA Dipartimento Tutela Acque Interne & Marine Via Brancati 48 I-00144 Rome Italy Sapienza Univ Roma Dipartimento Sci Stat Piazzale Aldo Moro 5 I-00185 Rome Italy

The assessment of pollution exposure is based on the analysis of a multivariate time series that include the concentrations of several pollutants as well as the measurements of multiple atmospheric variables. It typically requires methods of dimensionality reduction that are capable of identifying potentially dangerous combinations of pollutants and simultaneously segmenting exposure periods according to air quality conditions. When the data are high-dimensional, however, efficient methods of dimensionality reduction are challenging because of the formidable structure of cross-correlations that arise from the dynamic interaction between weather conditions and natural/anthropogenic pollution sources. In order to assess pollution exposure in an urban area while taking the above mentioned difficulties into account, we have developed a class of parsimonious hidden Markov models. In a multivariate time series setting, this approach simultaneously allows for the performance of temporal segmentation and dimensionality reduction. We specifically approximate the distribution of multiple pollutant concentrations by mixtures of factor analysis models, whose parameters evolve according to a latent Markov chain. Covariates are included as predictors of the chain transition probabilities. Parameter constraints on the factorial component of the model are exploited to tune the flexibility of dimensionality reduction. In order to estimate the model parameters efficiently, we have proposed a novel three-step Alternating Expected Conditional Maximization (AECM) algorithm, which is also assessed in a simulation study. In the case study, the proposed methods could (1) describe the exposure to pollution in terms of a few latent regimes, (2) associate these regimes with specific combinations of pollutant concentration levels as well as distinct correlation structures between concentrations, and (3) capture the influence of weather conditions on transitions between regimes.

关键词： Hidden Markov models AECM algorithm dimensionality reduction three-step algorithm

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Key points in dermoscopic differentiation between early acral melanoma and acral nevus

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JOURNAL OF DERMATOLOGY 2011年第1期38卷 25-34页

作者： Saida, Toshiaki Koga, Hiroshi Uhara, Hisashi Shinshu Univ Sch Med Dept Dermatol Matsumoto Nagano 390 Japan Shinshu Univ Hosp Clin Trial Ctr Matsumoto Nagano Japan

Acral skin is the most prevalent site of malignant melanoma in non-Caucasian populations. On acral skin, other various kinds of pigmented lesions are also detected. Particularly, melanocytic nevus is commonly seen on acral volar skin;approximately 10% of Japanese have a nevus on their soles. Prognosis of acral melanoma is still generally poor because of delayed detection in the advanced stages. To improve the prognosis, early detection is essential. Early acral melanoma is seen as a brownish macule, which is clinically quite similar to acral nevus. Therefore, clinicians often face a dilemma when they see a pigmented macule on acral volar skin. Introduction of dermoscopy was a great epoch in this field. Pigmentation pattern on dermoscopy is completely opposite between early acral melanoma and acral nevus;pigmentation on the ridges of the surface skin markings is detected in early acral melanoma, whereas pigmentation along the furrows of the skin markings is seen in acral nevus. We termed these dermoscopic patterns the parallel ridge pattern and the parallel furrow pattern, respectively. These features are highly helpful in the differentiation between the two biologically distinct entities. The sensitivity and specificity of the parallel ridge pattern in diagnosing early acral melanoma is 86% and 99%, respectively. However, we must be aware that dermoscopic features in acral nevus sometimes mimic the parallel ridge pattern and that other conditions also could show dermoscopic features similar to the parallel ridge pattern. In this review article, we summarize key points of the dermoscopic diagnosis of early acral melanoma and then describe the three-step algorithm for the management of acral melanocytic lesions, which surely aids us in effectively detecting early acral melanoma and in reducing unnecessary resection of benign nevus.

关键词： acral melanoma acral nevus dermoscopy early detection three-step algorithm

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Different Types of three-step DTZD algorithms for Time-Varying Inverse Square Root Finding 13

Different Types of Three-Step DTZD Algorithms for Time-Varyi...

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13th International Conference on Natural Computation, Fuzzy Systems and Knowledge Discovery (ICNC-FSKD)

作者： Guo, Dongsheng Liu, Qingping Su, Zhaozhu Huang, Zhijing Huaqiao Univ Coll Informat Sci & Engn Xiamen 361021 Peoples R China

ISBN: (纸本)9781538621653

On the basis of different error functions, a series of continuous-time Zhang dynamics (CTZD) models have been studied for time-varying inverse square root finding. For potential hardware implementation, the discrete-time forms of these CTZD models are further investigated. That is, by utilizing the Taylor-type difference rule to discretize the CTZD models, this paper proposes the corresponding discrete-time ZD (DTZD) algorithms to find time-varying inverse square root. Being a three-step iteration, each of the proposed DTZD algorithms is called the three-step DTZD algorithm in this paper. Theoretical results are also presented to highlight the computational properties of these three-step algorithms. With two illustrative examples, numerical results further demonstrate the effectiveness of the proposed algorithms in solving for time-varying inverse square root.

关键词： discrete-time Zhang dynamics (DTZD) time-varying inverse square root three-step algorithm Taylor-type difference rule theoretical and numerical verifications

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Phase Extracting and Unwrapping algorithm of Electrical Speckle Shearing Phase-shifting Pattern Interferometry 7

Phase Extracting and Unwrapping Algorithm of Electrical Spec...

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Conference on Holography, Diffractive Optics, and Applications VII

作者： Jing, Chao Zhou, Ping Zhang, Yimo Sci & Technol Opt Radiat Lab Beijing 100854 Peoples R China Tianjin Univ Tianjin 300072 Peoples R China

ISBN: (纸本)9781510604636;9781510604643

Electrical Speckle Shearing Phase-shifting Pattern Interferometry (ESSPPI) has been used in the fields of nondestructive testing (NDT) and stress field analysis as a precise deformation measuring method. The general fixed-step phase extracting algorithms of ESSPPI, such as three-step algorithms, four-step algorithms, five-step algorithms, and their corresponding errors are analyzed. It is proved that the phase accuracy of ESSPPI with different algorithms are mainly affected by linear error of phase-shifting. Therefore the modified four-step phase-shifting extracting algorithm that isn't sensitive to linear error of phase-shifting is adopted in the paper. The filtering algorithm should be employed to reduce the influences of speckle noise and wrong data caused by errors during measurement. Then the least-squares phase-unwrapping algorithm based on fast discrete cosine transform (LPABFDCT) is adopted to search the least-squares solutions between phase difference value of adjacent pixels and unwrapped phase difference value of the pixels and the real phase distribution caused by object deformation is obtained. The Electrical Speckle Shearing Phase-shifting Pattern Interferometric images are captured with four-step phase-shifting method and the real phase distributing image is achieved with modified four-step phase-shifting extracting algorithm, denoising filter and the least-squares phase-unwrapping algorithm based on fast discrete cosine transform. It is proved with experiment results that the real phase distributing images are effective achieved by mean of combination of average filter and the least-squares phase-unwrapping algorithm based on fast discrete cosine transform.

关键词： electrical speckle shearing phase-shifting pattern interferometry (ESSPPI) three-step algorithm four-step algorithm five-step algorithm modified four-step algorithm average filter discrete cosine transform the least-squares phase-unwrapping algorithm based on fast discrete cosine transform

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A new non-linear algorithm for complete pre-flight calibration of magnetometers in the geomagnetic field domain

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING 2009年第G6期223卷 729-739页

作者： Asl, H. Ghanbarpour Pourtakdoust, S. H. Samani, M. Sharif Univ Technol Ctr Res & Dev Space Sci & Technol Dept Aerosp Engn Tehran 113658639 Iran Islamic Azad Univ Sci & Res Branch Tehran Iran

A new algorithm for complete pre-flight calibration of triple magnetometers is developed. The traditional approach for calibrating these sensors are based on a cumbersome procedure called 'swing' that involves levelling and rotating the vehicle containing the magnetometers through a series of known headings. Application of such a procedure is difficult and costly. Recently, new approaches have been developed to calibrate magnetometers without the need of attitude information. Such methods are used mostly for the calibration of biases and scale factors. Additionally in situations where misalignment errors are also to be estimated, they are usually modelled as errors of a non-orthogonal frame relative to an orthogonal frame creating six additional unknown parameters to be estimated. The presented approach in this article utilizes a three-step algorithm to fully calibrate triple magnetometers without the need of attitude information through a batch least-square non-linear estimator. Since misalignment parameters are not all identifiable through attitude-independent techniques, the measurement equation is initially factorized such that the non-observable parameters are removed. This would allow identification of three parameters through attitude-independent techniques, while identification of the other three that require horizon information is carried out using a secondary procedure. In step one of the proposed scheme, the non-linear observation equation is transformed, via two non-linear functions, to a linear space with respect to the unknown parameters and the new unknown parameters are estimated with batch least-square estimator. In the second step, the first non-linear function is solved for nine parameters that have non-linear relationships with respect to the desired biases, scale factors, and misalignments. Subsequently, the second non-linear function is solved giving the main unknown calibration parameters in a non-physical frame. Finally, in the third step, to

关键词： magnetometer calibration non-linear estimator two-step algorithm three-step algorithm

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DNA-strand molecular beacon optical processor

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HELIYON 2019年第9期5卷 e02389-e02389页

作者： Thabit, Qabeela Q. Al-Saffar, Alaa A. Univ Basrah Dept Elect Engn Basrah Iraq Southern Tech Univ Dept Elect Power Engn Tech Basrah Iraq

Due to the characteristics of the newly developed DNA computing, many researchers are interested in this specialty. One advantage of DNA " Deoxyribonucleic acid" is that it has ability to resolve a Boolean circuit with various types of gates at the same time in a single level. Most of the prior models suffered from the limitations that each level of the circuit requests the gates to be of some kind. The model proposed in this work increases parallelism and reduces human intervention to a tremendous extent. When level-wise simulation is executed, the simulation for each model shows the decrease in the number of nitrogen bases used, which leads to the processing of the largest number of data with the ability to increase the length of a word, in addition to the adoption of the parallel principle of implementation. The model is designed on a mechanism which includes adder and multiplier.

关键词： Electrical engineering Binary modified signed digit (BMSD) Pipeline method Conventional method three-step algorithm DNA-Strand DNA computing Molecular beacon MB

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