Computer programs and calibration with the PIBS technique for quantitative electron probe analysis using a lithium-drifted silicon detector

A FORTRAN IV program for on-line analysis of silicates and oxides by electron microprobe fitted with a Si(Li) detector is described. The method allows for conversion to off-line batch processing. The ZAF (matrix corrections) routine uses precalculated functions wherever possible: this reduces calculation time to a few seconds. Also a program for monitoring the performance of the Si(Li) detector is listed.     

A mixed effects log-linear model based on the Birnbaum-Saunders distribution

In lifetime data analysis and particularly in engineering reliability contexts, the Birnbaum-Saunders (BISA) density is often suggested as a suitable model; see Birnbaum and Saunders (1969), Mann et al. (1974), and Desmond (1985). A linear regression model, obtained from a logarithmic transformation of the response variable, is useful in studying the effect of covariates on the response variable; see Rieck and Nedelman (1991), Tsionas (2001) and Galea et al. (2004). In this paper, an extension of the log-linear regression model of Rieck and Nedelman (1991), which considers random effects, is introduced. From a Monte Carlo simulation study, the performance of various estimation and prediction methods are studied. The usefulness of the mixed log-linear model is stressed and compared to the pure fixed effects log-linear regression BISA model. The new model is used to analyze a real data set, for which a fixed effects model is inappropriate.     

Feature extraction and decision procedure for automated inspection of textured materials

This paper proposes a general system approach applicable to the automatic inspection of textured material. First, the input image is preprocessed in order to be independent of non-uniformities. A tone-to-texture transform is then performed by mapping the original grey level picture on a multivariate local feature sequence, which turns out to be normally distributed. More specifically, features derived with the help of the Karhunen-Loève decomposition of a small neighbourhood of each pixel are used. A decision as to conformity with a reference texture is arrived at by thresholding the Mahalanobis distance for every realization of the feature vector. It is shown that this approach is optimum under the Gaussian assumption in the sense that it has a minimum acceptance region for a fixed probability of false rejection.     

A fast procedure for the training of neural networks

A new training paradigm for artificial neural networks is described. The technique utilizes a polynomial approximation to the sigmoidal processing function and directly integrates principal components analysis (PCA) into the network training philosophy. A major benefit of the new technique is that off-line network training is ‘one-shot’, contrary to the standard iterative techniques available in the literature. Further training may be performed on-line in a recursive fashion, yielding an adaptive neural network. Additionally, the new philosophy incorporates a systematic procedure for determining the number of neurons in the hidden layer of the network. The training procedure is first described and the implications of the training philosophy discussed. Some results, including applications to industrial chemical processes, are then presented to highlight the power of the technique. The systems considered are a continuous stirred tank reactor and a polymerization reactor.     

基于偏差校正的建模法在BPA结晶过程中的应用

从推理控制的基本思路出发,采用推算出干扰量继而实现前馈控制的方法,本文提出了一种基于输出偏差校正(deviation correction)的建模方法.该方法与支持向量机(support vector machine,SVM)相结合,形成DC-SVM算法.将DC-SVM方法应用于双酚A结晶过程软测量模型中,所得到的回归模型输出与SVM方法相比.塔底双酚A组分的最大相对误差和平均相对误差分别从7.97%和2.4%降到5.51%和1.8%,塔底苯酚组分的最大相对误差和平均相对误差分别从4.93%和1.11%降到3.46%和0.96%.本文提出的DC-SVM建模方法,可以广泛应用在回归建模中,也适合应用于实践生产过程,但需要足够的数据作为建模的基础.     

A syntactic procedure for the recognition of glottal pulses in continuous speech

Speech prosody contains an important structural information for performing speech analysis and for extracting syntactic nuclei from spoken sentences. This paper describes a procedure based on a multichannel system of epoch filters for recognizing the pulses of glottal chord vibrations by an analysis of the speech waveform. Recognition is performed by a stochastic finite state automaton automatically inferred after experiments.     

A test electron model for the study of three dimensional magnetic reconnection effects

Understanding the mechanisms that enable the conversion of the explosive release of magnetic energy into the electron energization that is experimentally observed in space and laboratory plasmas represents a long-standing question in the study of magnetic reconnection.     

A comparative analysis of score functions for multiple criteria decision making in intuitionistic fuzzy settings

The purpose of this paper was to conduct a comparative study of score functions in multiple criteria decision analysis based on intuitionistic fuzzy sets. The concept of score functions has been conceptualized and widely applied to multi-criteria decision-making problems. There are several types of score functions that can identify the mixed results of positive and negative parts in a bi-dimensional framework of intuitionistic fuzzy sets. Considering various perspectives on score functions, the present study adopts an order of preference based on similarity to the ideal solution as the main structure to estimate the importance of different criteria and compute optimal multi-criteria decisions in intuitionistic fuzzy evaluation settings. An experimental analysis is conducted to examine the relationship between the results yielded by different score functions, considering the average Spearman correlation coefficients and contradiction rates. Furthermore, additional discussions clarify the relative differences in the ranking orders obtained from different combinations of numbers of alternatives and criteria as well as different importance conditions.     

A gradient procedure for determining clusters of relatively high point density

We propose an algorithm for determining clusters of relatively high point density. The point density is defined by a Parzen estimate of the underlying probability density. A Gaussian bump is chosen for the Parzen window function. The algorithm puts points which can be connected by gradient lines to a maximum x₀ of the point density, into the same (gradient) cluster (around x₀). For this task a gradient procedure with step control is employed. We compare the procedure's convergence properties and computational expenses to those of other procedures for determining gradient clusters. Notes for choosing optimal standard deviations of the Gaussian bump are given.     

A new predictive model for compressive strength of HPC using gene expression programming

In this study, gene expression programming (GEP) is utilized to derive a new model for the prediction of compressive strength of high performance concrete (HPC) mixes. The model is developed using a comprehensive database obtained from the literature. The validity of the proposed model is verified by applying it to estimate the compressive strength of a portion of test results that are not included in the analysis. Linear and nonlinear least squares regression analyses are performed to benchmark the GEP model. Contributions of the parameters affecting the compressive strength are evaluated through a sensitivity analysis. GEP is found to be an effective method for evaluating the compressive strength of HPC mixes. The prediction performance of the optimal GEP model is better than the regression models.     

自整角机工艺误差的修正方法

在系统阐述自整角机工作原理的基础上 ,详细论述了在航空炮塔随动系统中 ,如何利用现有的自整角机来减小随动系统的误差以及消除假协调 ,从而使随动系统满足技战术指标。     

A computational procedure for response statistics-based optimization of stochastic non-linear FE-models

An approach for an efficient solution of response statistics-based optimization problems of non-linear FE systems under stochastic loading is presented. A sequential approximate optimization approach, where approximate stochastic analyses are used during portions of the optimization process, is implemented in the proposed formulation. In this approach, analytical approximations of the performance functions in terms of the design variables are considered during the optimization process. The analytical approximations are constructed by combining a mixed linearization approach with a stochastic response sensitivity analysis. The state of the system is defined in terms of the statistical second-moment characteristics of the structural response. The stochastic loading and the response of the system are represented by an orthogonal series expansion of the corresponding covariance matrices. In particular, a truncated Karhunen-Loève (K-L) expansion is applied. The system of non-linear equations is replaced by a statistical equivalent linear system. The evaluation of the K-L vectors is carried out by an efficient procedure that combines local linearization, modal analysis and static response of higher structural modes. An illustrative example is presented that shows the efficiency of the proposed methodology: it considers a building finite element model enforced with non-linear hysteretic devices and subject to a stochastic ground acceleration. Two types of problems are considered: a minimum structural weight design problem and an optimal non-linear device design problem.     

Dupan 3, a subroutine for the interpretation of duplicated data in geochemical analysis

Duplicated analytical results, properly obtained, can be used to estimate analytical standard deviation as a function of concentration of the analyte, with distinct advantage to other methods. A computer program is given which performs the necessary calculations and also enables the investigator to detect serious deviations from the theoretical model assumed.     

Experimental Analysis of Approximation Algorithms for the Vertex Cover and Set Covering Problems

Several approximation algorithms with proven performance guarantees have been proposed to find approximate solutions to classical combinatorial optimization problems. However, theoretical results may not reflect the experimental performance of the proposed algorithms. As a consequence, a question arises: how “far” from the theoretically proved performance are the experimental results? We conduct a controlled empirical study of approximation algorithms for the Vertex Cover and the Set Covering Problems. Many authors have proposed approximation algorithms for those problems. Our main goal is to better understand their strengths, weaknesses, and operation. Although we implement more than one algorithm to find feasible solutions to either problems, this work does not emphasize competition between them. The quality of the solutions related to the theoretical performance guarantees are analyzed instead. The computational experiments showed that the proven performance guarantees of all tested algorithms did not forecast well the empirical performance.     

The effect of shoe soling tread groove width on the coefficient of friction with different sole materials, floors, and contaminants

Tread groove design is very common in footwear. However, coefficient of friction (COF) measurements between the footwear material and floor using a slipmeter were commonly performed using flat footwear pads. Such measurements might underestimate the actual slip resistance of the footwear pad. This research investigates the effects of the tread groove width on the measured COF using four footwear materials, three floors, and four liquid-contamination conditions using a Brungraber Mark II slipmeter. The analysis of variance results indicated that the footwear material, floor, contamination conditions, and groove width were all significant (p<0.0001) factors affecting the measured COF. The hypothesis that wider tread grooves result in higher COF values was true with some exceptions especially on oil contaminated floors. A regression model, with an R² of 0.91, was established to describe and predict the relationship between the COF and the tread groove width under footwear material/floor/contamination conditions.     

Estimation algorithm of the bowel motility based on regression analysis of the jitter and shimmer of bowel sounds

Bowel sound (BS) signals can be used clinically as useful indicators of bowel motility. In this study, we devised a modified iterative kurtosis-based detector algorithm, in order to enhance the de-noising performance of BS signals, and an estimation algorithm of bowel motility based on the regression modeling of the jitter and shimmer of BS signals obtained by auscultation. The correlation coefficient, coefficient of determination and errors between the colon transit times measured by a conventional radiograph and the corresponding values estimated by our method were 0.987, 0.974 and 3.5 ± 3.3 h, respectively. These results demonstrated that our method could be used as a complementary tool for the non-invasive diagnosis and monitoring of bowel motility, instead of conventional radiography.     

A general mathematical formulation for finite-difference solution of mixed-boundary-value problems of anisotropic materials

This paper presents a general mathematical model, especially suitable for finite-difference analysis of stresses and displacements of the plane elastic problems of solid mechanics. The present formulation covers the problems of anisotropic, orthotropic and isotropic materials, in which the problem is formulated in terms of a single potential function, defined in terms of the displacement components. In addition, the formulation contains a new scheme of reduction of unknowns to be solved for a particular problem. Compared to the conventional computational approaches, the present scheme gets solution of higher accuracy and in extremely shorter time. The application of the present scheme is demonstrated here through a classical problem of solid mechanics, and the results are compared with the available solutions in the literature.