Review of Psychological Testing (3rd ed.).

Reviews the book, Psychological Testing (3rd ed.) by Anne Anastasi (1968). The many admirers and followers Anastasi incurred through the first two editions of this book along with her other writing will not be disappointed with this third edition. All of the testing knowledge apparently adequately updated, is still there, along with the familiar clarity and authority of expression. The third edition contains more useful-to-the-testing-purpose material than did either of the earlier editions. This feat has been accomplished in spite of the fact that the book is no longer than the others, containing 665 pages as opposed to 681 and 657 for the first and second editions respectively. This content improvement seems to have been brought about through the curtailment of less valuable data on the one hand and the inclusion of more recent and better material on the other. This edition of Anastasi's text contains enough new material in measurement to recommend that it be read by both students of and experts in the field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fatigue crack propagation in aluminium alloy NP8 determined from tests on 12.5 mm nominal thickness specimens

Fatigue crack growth tests were carried out on aluminium alloy BS1477 NP8 which has a 0.1% proof stress of 120 MN/m². The tests were performed in air at room temperature using centrecrack fracture toughness specimens of 12.5 mm nominal thickness. Crack growth rates were found to depend on the stress ratio σ_min/σ_max (the R ratio) and probably on specimen thickness, but not on net section yield. The results were similar to those reported by Frost using high strength aluminium alloys of 3–4 mm thickness, and this has been attributed to the increased thickness of the NP8 specimens. The individual da/dN vs Δ K results formed into bands depending on R; crack growth rates at each R value could be correlated in terms of the linear elastic fracture mechanics parameter ΔK, in the form da/dN=C(ΔK)ⁿ suggested by Paris. Crack growth rates were greater than predicted by expressions due to Frost based on thin low strength aluminium specimens and due to Pearson based on 12.7 mm thickness high strength aluminium specimens. A modified Pearson equation has been deduced which is in good agreement with the test results. Used in conjunction with an approximate expression for ΔK, the modified equation leads to conservative estimates of the number of cycles for a crack to reach a given length, which is a safe result of value in engineering practice.     

A New Synchronous Current Regulator and an Analysis of Current-Regulated PWM Inverters

Detailed models are presented for the stationary and synchronous sine-triangle current regulators. Analytical and test results are compared for purposes of model verification and regulator evaluation. The results demonstrate the limitations of the two most often used current regulators and the robustness of the synchronous current regulator. The stationary sine-triangle and hysteretic current regulators are shown to have steady-state characteristics that depend on slip, operating frequency, and motor impedance. In contrast the synchronous regulator, because it lacks these dependencies, exhibits ideal steady-state current regulator characteristics without sacrificing bandwidth. Moreover, the complexities traditionally associated with the synchronous regulator are overcome with a simple equivalent implementation.     

A new flux and stator resistance identifier for AC drive systems

The effect of stator resistance on AC drive performance is analyzed for flux vector and indirect field-oriented controllers. A new technique-the back electromagnetic force (BEMF) detector-for reducing the adverse effects of stator resistance on field-oriented control is presented and evaluated through simulation and experimental results. The BEMF detector is shown to reduce the impact of the stator resistance variations and also provide an estimate of the stator resistance. The detector is compatible with most control strategies and with or without position feedback     

Performance analysis of large systems

A hybrid analytic and experimental approach to the analysis of large systems is described. The approach is iterative under the assumption that a correct analysis will not be made first time. It is primarily aimed at the analysis of the performance effect of proposed changes prior to coding them. The requirement is for a fairly approximate analysis that is easy to make. The approach is illustrated by an experiment on a relational database system but we believe it to be applicable to many kinds of large systems. The different reasons for analysing performance of a system are discussed and then the ways of approaching the analysis, with an outline of our approach. The details of our approach are given, and illustrated by our experiment.