A Virtual Instrument for the Measurement of IEEE Std. 1459-2000 Power Quantities

In this paper, the authors present a PC-based instrument for the measurement of electrical-power quantities defined in IEEE Std. 1459. The instrument is based on a time-domain technique for the detection of the fundamental and harmonic components of voltages and currents. The time-domain strategy was originally developed by the authors for three-phase, three-wire systems. In that paper, the strategy had been extended to both three-phase, four-wire and single-phase systems. Simulation tests were carried out to assess the uncertainty contribution of the proposed strategy in the absence of the measurement transducers. Moreover, the accuracy of the PC-based instrument with its transducers was evaluated; the experimental tests were carried out by using a power calibrator.     

Disturbing Load Identification in Power Systems: A Single-Point Time-Domain Method Based on IEEE 1459-2000

This paper presents a single-point method for the identification of prevailing disturbing loads in power systems for both single-phase and three-phase applications downstream or upstream from the metering section. It is based on the simultaneous measurement of three nonactive power quantities, which are based on the IEEE Std. 1459-2000 approach. The proposed method is only based on the separation of the fundamental components from the harmonic content of voltage and current; thus, it does not require any spectral analysis of the voltages and current. In this paper, the formulation of the proposed method and its time-domain implementation are described; moreover, some simulation results are presented and discussed, showing the effectiveness of the method both in the absence and in the presence of the measurement transducers.     

An AC Josephson Voltage Standard for AC–DC Transfer-Standard Measurements

We describe the traceability chain of length measurements at Centre for Metrology and Accreditation (MIKES) from atomic clocks to the lasers of primary interferometers. Crucial part of the traceability chain, an optical frequency comb generator linking optical frequencies to atomic clocks, is described in detail. The frequency comb generator is used in frequency calibrations of iodine-stabilized lasers, which are operated in compliance with the recommendations of the practical realization of the definition of the meter. Measured absolute frequencies of iodine-stabilized lasers, time records of the measurements, and the respective Allan deviations demonstrate the solid performance of the MIKES laser frequency standards. The results are in good agreement with the recommended values, as well as with the independent characterizations of the measured lasers     

AC–DC Transfer Standard Measurements and Generalized Compensation With the AC Josephson Voltage Standard

We present AC-DC transfer standard measurements using the National Institute of Standards and Technology's pulse-driven AC Josephson voltage standard source. We have investigated the frequency dependence for several output voltages up to 200 mV for frequencies from 2.5 to 100 kHz. We found that, as the frequency increases, the ac-dc differences for the two arrays on the same chip do not agree. We explored this deviation in ac-dc difference for the two arrays by investigating different configurations of the probe cabling and wiring, chip carriers, and on-chip circuit design. We found that the circuit design produced the greatest improvement, particularly at the highest frequency (100 kHz), where the deviation in ac-dc difference was reduced by more than 60%. In this paper, we also demonstrate tenfold higher output voltages and improved operating margins for arbitrary (nonsinusoidal) waveforms. These enhancements were accomplished by implementing a more general current bias to the arrays having the same harmonic content as that of the synthesized arbitrary waveform.     

一个工效挂钩的改进方法

效益基数和挂钩方式的确定是工效挂钩的焦点和难点.将企业当年能实现的最大利润作为松弛变量导入效益基数,并将工资总额增长改为与超额利润定比分成,来建立一个松弛模型;理论分析和演算证实,此方法能促使国有企业(代理方)正确评估并完成其能实现的最大利润,并比采用历史效益基数和挂钩浮动系数的现行方法能更有效地激励国有企业实现国家(委托方)利益最大化.     

Adaptive l1–l2 curve fitting

In References 1 and 2, algorithms were introduced for adaptively computing smooth piecewise polynomial approximations using uniform, least-squars (l₂) and restricted-range uniform approximations. This present paper introduces a FORTRAN program for computing smooth piecewise polynomial approximations to data and/or precise mathematical functions (in discrete form) which allows the user the option of using best l₁ of best l₂ approximations. (The l₂ option of this newly developed l₁–l₂ adaptive curve-fitting package supersedes the code listed in Reference 1 for the old least-squares program.) In this paper, adaptive curve-fitting algorithm used in this l₁–l₂ package is described in detail, the FORTRAN program is the given (in the Appendix) and discussed, the numerical results are presented in an effort to illustrate how the l₁ and l₂ versions of this algorithm may be used most effectively.     

A Combined TD–FD Method for Enhanced Reflectometry Measurements in Liquid Quality Monitoring

Measurement and control of the dielectric parameters of liquids play a major role in industrial quality-control applications. Although several techniques are currently available to this aim, none of them is simultaneously accurate, cost-effective, and reasonably quick. On the other hand, reflectometry has become a very attractive method for monitoring applications, mostly thanks to its accuracy and flexibility. In this paper, a combined method based on time-domain reflectometry (TDR) and frequency-domain (FD) analysis is presented: the aim is to substantially improve the measurement accuracy of the dielectric parameters of liquids. Starting with typical TDR measurements, the associated FD evaluation of the dielectric parameters is considerably enhanced through the combined effect of the following: 1) specific data-processing techniques; 2) the implementation of a calibration procedure; and 3) the final modeling and minimization routine. Furthermore, to definitively assess the proposed combined procedure, results are compared with measurements directly performed in the FD through a vector network analyzer (VNA). The ultimate goal of the work is to pave the way for the adoption of inexpensive and portable TDR devices in practical industrial monitoring applications.     

An Adaptive Multi-resolution Method for Solving PDE's

In this paper, we present a multi-resolution adaptive algorithm for solving problems described by partial differential equations. The technique is based on the collocation method using Fup basis functions, which belong to a class of Rvachev's infinitely differentiable finite functions. As it is possible to calculate derivation values of Fup basis functions of high degree in a precise yet simple way, so it is possible to efficiently apply strong formulation procedures. The mesh free method developed in this work is named Adaptive Fup Collocation Method (AFCM). The distribution of collocation points within the observed area is changed adaptively, depending on the character of the solution function and the accuracy criteria. The numerical procedure is designed through a method of lines (MOL). The basic characteristic of the method is an adaptive multi-resolution approach in solving problems with different spatial and temporal scales and with a desired level of accuracy using the entire family of Fup basis functions. Good performance of the proposed method is shown through the numerical examples by using a few general advection dominated problems. The results demonstrate that the method is very convenient for solving engineering problems which require extensive computational resources, especially in describing sharp fronts or high gradients and changes of narrow transition zones in space and time.     

The state of multivariate thinking for scientists in industry: 1980–2000

Chemometrics has enjoyed tremendous success in the areas related to calibration of spectrometers and spectroscopy-based measurements. These chemometric-based spectrometers have been widely applied for process monitoring and quality assurance. However, chemometrics has the potential to revolutionize the very intellectual roots of problem solving. Are there barriers to a more rapid proliferation of chemometric-based thinking, particularly in industry? What are the potential effects of chemometrics technology and the New Network Economy (NNE) working in concert? Who will be the winners in the race for faster, better, cheaper systems and products? These questions are reviewed in terms of the principles of the NNE and in the promise of chemometrics for industry. What then is the state of multivariate thinking in industry? Several powerful principles are derived from an evaluation of the NNE and chemometrics which could allow chemometrics to proliferate much more rapidly as a key general problem-solving tool.     

求解Stokes方程的一种自适应变分多尺度方法

针对Stokes方程,本文给出一种新的变分多尺度方法.此方法通过构造特殊投影并采用局部化技巧优化了经典变分多尺度方法.同时,本文对此方法进行了后验误差估计,并给出可靠的后验误差估计子及相应的自适应算法.此自适应变分多尺度方法计算简单且易于程序实现.L型区域问题和方腔流问题的数值结果验证了方法的有效性和稳定性.     

Maggots in paradise––work for the gardeners

The landscape of the patent information market is continuously changing and confronts patent offices, database producers, hosts and information professionals with new challenges. The author describes the users' needs seen from a chemical industry viewpoint. She also examines some of the forces shaping this landscape and questions just how fruitful these recent developments may be.     

An Investigation of the Measurements Systems Analysis “Analytic Method” for Attribute Gages

Three automotive corporations have developed and sanctioned the recently revised reference manual entitled Measurement Systems Analysis. This “standard” contains a procedure, called the “analytic method,” whose purpose is to estimate the gage bias and gage repeatability of an attribute gage. An improved estimation procedure for this standard is presented. The improved estimation procedure yields more accurate estimates than those obtained using the procedures currently presented in the standard. In addition, the improved procedure allows more flexibility in data collection than the current test protocol. A simulation study that evaluates the estimation procedure of the current standard and compares it with the improved estimation procedure is presented. Errors that are contained in the present standard are also noted.     

A bibliography of the literature on process capability indices: 2000–2009

This paper contains a bibliography of approximately 530 journal papers and books on process capability indices for the period 2000–2009. The related literature is classified into four major categories, namely, books, review/overview papers, theory‐ and method‐related papers, and special applications. Theory‐ and method‐related papers are further classified into univariate and multivariate cases, and special applications include acceptance sampling plans, supplier selection, and tolerance design and other optimizations. Copyright © 2010 John Wiley & Sons, Ltd.     

Modelling of laser forming – An review

Laser forming is achieved by plastic deformation induced by thermal stresses resulting from rapid nonlinear thermal cycles. Unlike mechanical forming, the process requires no hard tooling or external forces and thus there is no spring-back effect. A number of mechanisms have been identified to explain the thermo-mechanical behaviour in laser forming, accounting for various part geometries, laser process conditions and many materials. Although these interactions of thermal and mechanical factors are not yet fully understood, with increased knowledge of the laser forming process, the process offers significant potential value to industry such as aerospace, shipbuilding, microelectronics, etc. Modelling of the laser forming process may help to provide a basis for determining the heating pattern required, therefore making application of laser forming feasible and profitable to industry. This review describes a number of recent developments and new techniques in modelling of laser forming, including analytical models, numerical simulations and various empirical models.     

An Adaptive Meshless Method for Magnetic Field Computation

Increasing energy cost and advance in permanent magnet technology have provided the incentives to develop geometrically compact and energy-efficient electromagnetic (EM) actuators. Design of electromagnetic (EM) actuators often involves solving a magnetic field problem. This paper presents an adaptive meshless method (MLM) that inherits many advantages of the finite-element method (FEM) but needs no explicit mesh structure for design of EM actuators. Specifically, the paper offers a technique to estimate the distribution of numerical errors and a scheme that automatically inserts additional nodes to improve computational accuracy and efficiency. It gives several examples. The first three numerical examples, where exact solutions are available, provide a means to validate the adaptive MLM and evaluate its effectiveness against a regular MLM with a uniform node distribution. The other examples, where magnetic forces are computed from Lorenz's law, illustrate the use of adaptive MLM for practical design of an EM actuator. The paper compares the computed forces against published experimental results.