Iterative Analysis Method Research Articles

若材齢コンクリートのクリープ及び拘束変形特性

In this paper, the creep behavior and the restrained deformation property for early age concrete were investigated by the rheological analysis method based on the burgers model for a non-linear function and the iterative analysis method based on the creep superposition. According to the analysis, the following results were clarified: 1) The creep behavior in early age could be considered by the rheological coefficient model on a time dependence for early age concrete. 2) The restrained deformation analysis method based on creep solution by the rheological coefficient model was proporsed. 3) The rheological analysis method based on the burgers model for a non-linear function was effective for early age concrete.

Registros da atividade solar nos anéis de crescimento de árvores em São Francisco de Paula - RS (Brasil)

The most important aspect of the solar variability is the 11 year-old cycle, observed in sunspot number variations. This cycle has already been observed in terrestrial records, such as the nuclear activity variations of cosmogenic 14C from tree rings and 10Be in ice sample of polar caps, by sophisticated and high cost methods. By more simple methods, chronologies of tree ring width index recently began to be used as possible record of the solar activity variations in the past. In different locations of the world an influence of the 11 year-old solar cycle was observed in tree growth rings. However, in some other places it was not possible to find the influence of solar activity variations in trees. This led us to perform a study of the possible influence of the solar activity in tree rings from trees grown in South America. The tree rings width determination is made using an optical and computational methodology. This work shows the results obtained at one of the locations studied, at San Francisco of Paula, Brazil. A 65 year-old mean chronology was determined for the tree ring width at this place. For the periodicity search, related to the phenomena of solar origin, the iterative regression analysis method was used. Periods were found at 20.7, 12.8 and 5.6 years related to the cycles 22 year solar (Hale Cycle), 11 year (Schwabe cycle) and the second harmonic of the 11 year cycle. It was also found a 8.6 year period, which is due to periodical thinning down for forest management and preservation.

Toward a discipline of scenario-based architectural engineering

Software architecture analysis is a costdeffective means of controlling risk and maintaining system quality throughout the processes of software design, development and maintenance. This paper presents a sequence of steps that maps architectural quality goals into scenarios that measure the goals, mechanisms that realize the scenarios and analytic models that measure the results. This mapping ensures that design decisions and their rationale are documented in such a fashion that they can be systematically explored, varied, and potentially traded off against each other. As systems evolve, the analytic models can be used to assess the impact of architectural changes, relative to the system’s changing quality goals. Although scenarios have been extensively used in software design to understand the ways in which a system meets its operational requirements, there has been little systematic use of scenarios to support analysis, particularly analysis of a software architecture’s quality attributes: modifiability, portability, extensibility, security, availability, and so forth. In this paper we present a unified approach to using scenarios to support both the design, analysis and maintenance of software architectures, and examples from largedscale software development projects where we have applied the approach. We also present a tool, called Brie, that aids in: scenario capture, mapping scenarios to software architectures, and the association of analytic models with particular portions of architectures. The approach that we have devised, and that Brie supports, is a foundation for a discipline of architectural engineering. Architectural engineering is an iterative method of design, analysis and maintenance where design decisions are motivated by scenarios, and are supported by documented analyses.

Efficient iterative method for analysis of large finite phased arrays

A novel iterative method for the solution of large systems of linear equations in analyzing large finite phased arrays is proposed. Avoiding the calculation of large matrices and giving a good approximation of the currents initially this iterative algorithm shows an excellent convergence. A computational example is presented to illustrate its high efficiency. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 44–46, 1999.

Iterative regression analysis of periodicities in geophysical record time series

The aim of this work was to use an Iterative Regression Analysis Method for the determination of periodicities in geophysical time series. This method gives, for every identified sine function, its three parameters and their standard deviation due to measurement errors and to the presence of adjustment residues. This feature allows to select the most important periodicities with higher amplitude/deviation ratio. The method described was applied to the analysis of the main periodicities in time series of atmospheric cosmonuclides (atmospheric carbon 14 and beryllium 10 of ice cores from Greenland and Antarctica), mean surface temperatures and indicators of atmospheric volcanic dust. During the time interval of these series, the periodicities found were compared from the point of view of possible causal associations between such phenomena as solar activity, cosmonuclide concentrations in the terrestrial atmosphere, atmospheric circulation, temperatures of the air and volcanic dust in the atmosphere.

An iterative discriminant analysis method to search for the Higgs particle at LEP2

The search for the Higgs boson in e +e − collisions at energies above the Z 0 mass requires an efficient method to reject the many background channels. We have investigated an iterated discriminant analysis to detect the signal of a Higgs boson produced in association with neutrinos. An efficiency for a 70 GeV/ c 2 Higgs particle of 50% and a background rejection factor of 290 000 have been achieved. The optimization and performance of the iterated discriminant analysis are described.

Weak Sharp Solutions of Variational Inequalities

Weak Sharp Solutions of Variational Inequalities

Dual iterative displacement analysis of spatial mechanisms using the C H programming language

A dual iterative method for displacement analysis of spatial mechanisms is presented in this paper. The algorithm and formulation based upon 3 × 3 dual transformation matrices are succinct. They can be implemented concisely in the C H programming language, a superset of C, which handles dual, double dual, and dual computational arrays polymorphically. The algorithm is numerically verified by dual iterative displacement analysis of spatial mechanisms. Comparison studies on stability, convergence, performance near singularities, and CPU time of the dual iterative method versus the real iterative method are conducted. It is shown that both dual and real iterative algorithms are stable with a comparable convergence rate even near singularities. However, the computational speed of the dual iterative formulation is about 2.18 times faster than that of the real iterative formulation when formulations are translated into C H programs for numerical calculation.

Dynamic NMR: A new procedure for the estimation of mixing times in the 2D EXSY experiments. A four‐site exchange system studied by 1D and 2D EXSY spectroscopy

AbstractA procedure for the estimation of the mixing time between the last two 90° pulses in the classic three‐pulse sequence NOESY/EXSY is proposed and tested and some considerations for the treatment of the two‐dimensional (2D) 1H NMR exchange spectra are given. The rate constants are thus obtained with reasonable precision. This procedure was followed to obtain the 2D spectra of the model compound α‐[bis(dimethylamino)methylene]‐4‐nitrophenylacetonitrile, which represents a four‐site exchange system. The barriers to restricted rotations found in this compound were also determined from one‐dimensional (1D) 1H NMR spectra, which were processed with the iterative complete lineshape analysis (CLSA) method. The double‐fit approach was incorporated in the CLSA method. It is shown that the results from the 2D dynamic NMR spectral studies corroborate those obtained by the CLSA double‐fit method.

Analysis of a double shear lap joint with interference fit pin

This paper presents the study of stress distribution in a double-shear lap joint with interference fit pin subjected to inplane plate loads using FELJNT, a finite element software developed for this special purpose. FELJNT accounts for the effects of clamping and flexure of the bolt without having to adopt a laborious three-dimensional analysis. It carries out stress analysis in an axisymmetric region around the pin under non-axisymmetric loading. It uses an iterative method of contact stress analysis and a dummy element concept with frontal solver for finite element solution. This paper discusses the load for initiation of separation, through-the-thickness stress distribution, and qualitatively the beneficial effects of interference on fatigue life of the joint. The paper concludes with comparison of FELJNT results with those of JACKAL, a three-dimensional finite element analysis software for joints.

Second-order drift force response of offshore guyed towers

An iterative frequency domain method of analysis is presented for determining the response behaviour of Guyed Offshore Towers to low-frequency, second-order wave drift forces generated in a random sea environment. For the response analysis, the tower is idealized as a shear beam with a rotational spring at the bottom support. The guylines are replaced by a non-linear spring. The second-order drift force is considered to be proportional to the square of the wave elevation and is simulated using a drift force coefficient and the time history of a slowly varying wave envelope in random sea. The responses due to drift forces are obtained in frequency domain by incorporating the non-linearities produced due to non-linear guy lines. An example problem is solved under different random sea states to compare the response behaviour of the tower obtained by the second-order wave force, the first-order wave force and a combination of the two.

On the characteristics of an off-centre bracing system

A particular off- centre bracing system (OBS) is introduced. In this system the tensile diagonal strut is not straight. Once the load is applied, the original geometry changes and, therefore, the load-deflexion of such a system becomes geometrically non-linear. An iterative method of analysis has been developed to study the non-linear load-deflexion behaviour of off- centre bracing systems (OBS). The results indicate that the stiffness increases with load and that the load-deflexion characteristics can be similar to that of hardening springs. The degree of non-linearity mainly depends on the eccentricity of the tension diagonal and the relative stiffness of bracing members. The non-linear characteristics of OBS were then considered as an effective expedient for mitigation of seismic loads. A non-linear program was developed to analyse seismic response of off-centre bracings subjected to various collapse-level earthquakes. The results indicate that OBS behave generally like base isolated systems and that the response may be reduced remarkably by pre-adjustment of eccentrcity and relative stiffness of bracings.

Iterative Principal Axes Registration method for analysis of MR-PET brain images.

Computerized automatic registration of MR-PET images of the brain is of significant interest for multimodality brain image analysis. In this paper, we discuss the Principal Axes Transformation for registration of three-dimensional MR and PET images. A new brain phantom designed to test MR-PET registration accuracy determines that the Principal Axes Registration method is accurate to within an average of 1.37 mm with a standard deviation of 0.78 mm. Often the PET scans are not complete in the sense that the PET volume does not match the respective MR volume. We have developed an Iterative Principal Axes Registration (IPAR) algorithm for such cases. Partial volumes of PET can be accurately registered to the complete MR volume using the new iterative algorithm. The quantitative and qualitative analyses of MR-PET image registration are presented and discussed. Results show that the new Principal Axes Registration algorithm is accurate and practical in MR-PET correlation studies.

Itrative design‐oriented analysis method for class‐ab high‐efficiency microwave power amplifiers

AbstractOptimum choice of bias point, load and drive level for solid‐state power amplifiers is performed via a design methodology based on a novel iterative analysis method. The effectiveness of the proposed methodology and the corresponding level of accuracy is demonstrated through a comparison with the results of a more elaborate commercial CAD software and with experimental data, © 1994 John Wiley & Sons, Inc.

A new iterative method for the global simulation of power electronic multi-converter systems

Power electronic converters generate harmonic currents that can disturb the network. To study the perturbations on the power line, it is necessary to perform a functional analysis via a global simulation. However, when the plant contains several static power converters feeding direct-current loads, global simulation becomes difficult, even impossible, because of the limitations of the software or the microcomputer used. There are no simulation tools that allow the quantitative evaluation of harmonic voltages and currents generated by a multistatic converter system. To fulfil this goal, the authors propose a new iterative analysis method for such systems and a new model for electronic power converters in terms of nonlinear current sources. This methodology has been included in a modified version of the ATOSECS software, renamed ATOSECM. The methodology is illustrated with an example of the use of ATOSECM on a personal computer for the study of two single-phase power converters connected to the same power line. A comparative analysis between global simulation (ATOSECS) and the new method of simulation (ATOSECM) is also presented for the case of two three-phase full-wave thyristor converters, with different firing angles and loads.

Diffraction anomalous fine structure: a new technique for probing local atomic environment

Diffraction anomalous fine structure (DAFS) is the fine structure in the intensity of an X-ray diffraction peak in the vicinity of an absorption edge. DAFS is measured by monitoring the intensity of a diffraction peak as a function of the incident X-ray energy as it is scanned through an absorption edge. It combines the short range structural sensitivity of X-ray absorption spectroscopy with the long range periodicity of X-ray diffraction and can provide structural information which is not available from these techniques alone or in combination. We demonstrate the technique for several different dilute, polycrystalline samples, and present an iterative data analysis method which allows the extraction of a specific X-ray absorbance spectrum from the DAFS spectrum

An improvement of the iterative harmonic analysis method

AbstractThe paper proposes an iterative method as a possible improvement of the classical power system harmonic analysis method known as IHA (Iterative Harmonic Analysis). Such improvement is indicated when convergence problems occur as consequence of supply system resonances, low short‐circuit ratios or strong interactions in the operation of non‐linear devices. The iterative method proposed is described and then some considerations on its accuracy and computational efficiency are carried out. Finally numerical experiments referring to single converter as well as multi‐converter installations are reported to show the applicability and the usefulness of the iterative method proposed.

Introduction of the Phone-Concept Into Pole Figure Inversion Using the Iterative Series Expansion Method

The phone-concept as it is used in the various kinds of probabilistic methods can easily be applied to the iterative series expansion method for quantitative texture analysis. Only slight modifications of the existing routines are necessary. The advantages of this concept are demonstrated by a mathematical and an experimental example.

On truncated poisson distribution for determining mean number of defectives in pharmaceutical products

AbstractThe Poisson distribution plays a dominant role in the determination of the mean value of a distribution of the number of defective units (e.g. tablets, capsules) per sample, based on several samples of same size. If, however, the data emanates from samples with at least one defective unit in each sample, involving the absence of the zero-defective category, then the formula of the Poisson distribution as well as of the mean number of defective units are no longer tenable. In this presentation, appropriate formula for the Poisson distribution, called the truncated Poisson distribution, and for the mean, θ, are developed. The maximum likelihood method of estimation of the parameter θ by employing numerical (iterative) analysis methods is depicted, in detail. The procedure for conducting the chi-square test of goodness of fit of the experimental data to the truncated Poisson distribution is demonstrated. The results of the analyses of two recent experiments based on the methods described above are pr...

Numerical calculation of flow properties and specific interaction forces in solid-liquid flows.

An iterative calculation method for quantitative analysis of solid-liquid two phase flows is presented based on the momentum equation of the solid phase, the liquid phase, and the mixture of the two. This method yields the momentum diffusion coefficients for the three phases, the specific interaction forces, the slip velocity between the liquid and the solid phase, and velocities of the liquid and the mixture phase.Data necessary for the calculation are the velocity, the concentration distribution of the solid phase measured with a conductive probe, and the pressure loss gradient of solid-liquid flows.The results f the calculation supply a quantitative means of calculation of the iteraction between dispersed particles and a carrier liquid.