Pareto optimality for rational comprehensive decision making

Abstract

The majority of industrial problems, like real life personal problems, involve the achievement of more than one objective, though there could be different levels of preference for these objectives. Few solution techniques would solve such problems and still retain the original images of the problems. PARETO OPTIMALITY is recommended as a tool for achieving meaningful, factual, systematic solutions to such problems, by retaining their identities, and providing a rational and comprehensive approach towards the generation of superior solution alternatives and decision maker preferred solutions.     

Influence of Cavitation on Unsteady Vortical Flows in a Side Channel Pump

Double-sided lapping is an precision machining method capable of obtaining high-precision surface. However, during the lapping process of thin pure copper substrate, the workpiece will be warped due to the influence of residual stress, including the machining stress and initial residual stress, which will deteriorate the flatness of the workpiece and ultimately affect the performance of components. In this study, finite element method (FEM) was adopted to study the effect of residual stress-related on the deformation of pure copper substrate during double-sided lapping. Considering the initial residual stress of the workpiece, the stress caused by the lapping and their distribution characteristics, a prediction model was proposed for simulating workpiece machining deformation in lapping process by measuring the material removal rate of the upper and lower surfaces of the workpiece under the corresponding parameters. The results showed that the primary cause of the warping deformation of the workpiece in the double-sided lapping is the redistribution of initial residual stress caused by uneven material removal on the both surfaces. The finite element simulation results were in good agreement with the experimental results.     

Analytical determination of cyclic hydrostatic stress-strain relations for a composite sphere with a soft inclusion and a hard bilinear, isotropically hardening matrix

Summary This paper deals with the analytical determination of cyclic hydrostatic stress-strain relations for an inclusion-matrix concentric sphere. Both phases are taken to be elastically isotropic, and the inclusion is taken as elastically softer than the matrix. The matrix is taken to be bilinear, and isotropic hardening is assumed. Yielding is assumed to occur in the matrix by the von Mises' criterion. Using Hill's [1] approach as a starting point, the exact solution is first determined for the first five sequences of loading (i.e., alternate tensile and compressive loadings). Based on the developed equations for the first five sequences and an inductive approach, the analytical relation for the overall hydrostatic stress and strain for the N^th loading sequence issuggested. With the developed equations the Bauschinger effect for the composite sphere is studied. Interestingly, it is seen that irrespective of the inclusion volume fraction, the relative stiffness of the soft inclusion/hard matrix or the work-hardening nature of the matrix, the composite response is initially governed by isotropic hardening, whereas an asymptotic response is approached where both kinematic and isotropic mechanisms play equally important roles. Such an evolution in the composite response is attributed to the evolution in internal stresses of the composite sphere.     

Implementing the Lorenz oscillator with translinear elements

Nonlinear processing is often more suitable than the traditional linear approach is for analyzing biological signals. Unfortunately, digital nonlinear operations are computationaly expensive. In contrast, a large variety of nonlinear operations can efficiently be implemented in analog electronics, operating at real-time speeds. The low level of accuracy generally associated with analog processing is not a concern in this scenario, as biological signals themselves typically have low signal-to-noise ratios. One challenge of analog processing is in its apparently-ad hoc design, and the fact that there is very little wide-spread knowledge of systematically implementing analog electronics to perform arbitrary nonlinear computations. Another issue is the integrity of the analog components; the analog properties of electronic devices are prone to a large amount of mismatch. In this paper, we examine multiple-input translinear element (MITE) networks, a class of analog circuits that addresses the two concerns of a structured synthesis procedure and component mismatch. We test the ability of these MITE networks for accurately realizing linear and nonlinear systems with prescribed dynamics by attempting to implement the Lorenz equations. We will present the theoretical procedure, address practical implementation issues, and then show experimental results from a version of the circuit fabricated in a 0.5 μm CMOS technology through MOSIS.     

Evaluating ‘new’ instrumentation and control technologies for safety-related applications in nuclear power plants

As obsolescence and spare parts issues drive nuclear power plants to upgrade with new technologies (such as optical fiber communication systems), the ability of the new technologies to withstand environmental stresses that act at the installation location needs to be determined. New standards may be required to address environmental qualification and their application to the nuclear power plants of tommorow. This article discusses the failure modes and age-related degradation mechanisms relevant to fiber-optic communication systems in particular, and suggests a methodology for identifying conditions under which accelerated aging should be performed during qualification testing. While optical fiber communication systems have been used as the basis for discussion, the methodology presented should be applicable to any safety-related instrumentation and control equipment not covered under Title 10 of the Code of Federal Regulations (10 CFR 50.49).     

A microphone readout interface with 74-dB SNDR

A continuous-time (CT) sigma-delta modulator (SDM) for condenser microphone readout interfaces is presented in this paper. The CT SDM can accommodate a single-ended input and has high input impedance, so that it can be directly driven by a single-ended condenser microphone. A current-sensing boosted OTA-C integrator with capacitive feedforward compensation is employed in the CT SDM to achieve high input impedance and high linearity with low power consumption. Fabricated in a \(0.35\) - \(\upmu\) m complementary metal-oxide-semiconductor (CMOS) process, a circuit prototype of the CT SDM achieves a peak signal-to-noise-and-distortion ratio of 74.2 dB, with 10-kHz bandwidth and \(801\) - \(\upmu\) W power consumption.     

Black and White Viewers' Perception and Recall of Occupational Characters on Television

This study examined the differences in how Black and White viewers process messages based on the race of television characters representing 5 occupations. Black and White male viewers were exposed to either 5 Black or 5 White male television characters representing 5 different occupations (i.e., lawyer, doctor, professor, engineer, and business student). Findings from 81 male Black and White college students suggest that Black viewers have better recall of Black occupational characters on television than they do White occupational characters on television. Unexpectedly, the results show evidence that both Black and White viewers' perceptions of occupational characters were positively affected by the race of the Black character. Theoretical and practical implications are also discussed.     

Scattering matrix interpolation from the perturbation method: application to calculation of a grating's electromagnetic and scatterometric signatures

The scatterometric and electromagnetic signatures of a pattern are computed with the perturbation method combined with the Fourier modal method in order to reduce computational time. From an electromagnetic point of view, the grating is characterized by its scattering matrix, which allows the computation of the reflection and transmission coefficients. A slight variation of profile parameters or electrical ones provides a small fluctuation of the scattering matrix; consequently, an analytical expression of the local behavior of its eigenvectors and eigenvalues can be obtained by using a perturbation method.