Explaining the relation between IQ and delinquency: Class, race, test motivation, school failure, or self-control?

An inverse relation between IQ and delinquency has been well established, but the direction of effect remains to be specified. Differing explanatory accounts of the relation were empirically examined in the present study using data on 13-yr-old boys involved in a high-risk longitudinal study. Accounts that interpreted the relation as spurious or that posited that delinquency-related factors lead to low IQ scores received no support; findings were most consistent with the hypothesis that the direction of effect runs from low IQ to delinquency. The IQ–delinquency relation was robust after race, class, and observed test motivation were controlled statistically. Additionally, the effect of IQ was mediated by school performance for Black youth but not for White youth. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combining multiway principal component analysis (MPCA) and clustering for efficient data mining of historical data sets of SBR processes.

A methodology based on Principal Component Analysis (PCA) and clustering is evaluated for process monitoring and process analysis of a pilot-scale SBR removing nitrogen and phosphorus. The first step of this method is to build a multi-way PCA (MPCA) model using the historical process data. In the second step, the principal scores and the Q-statistics resulting from the MPCA model are fed to the LAMDA clustering algorithm. This procedure is iterated twice. The first iteration provides an efficient and effective discrimination between normal and abnormal operational conditions. The second iteration of the procedure allowed a clear-cut discrimination of applied operational changes in the SBR history. Important to add is that this procedure helped identifying some changes in the process behaviour, which would not have been possible, had we only relied on visually inspecting this online data set of the SBR (which is traditionally the case in practice). Hence the PCA based clustering methodology is a promising tool to efficiently interpret and analyse the SBR process behaviour using large historical online data sets.     

MPEGTool: An X window-based MPEG encoder and statistics tool

In this paper, we describe MPEGTool, an X window-based tool that can be used to generate a motion picture expert group (MPEG) encoded bit stream for video sequences and to study the statistical properties of the encoded data. The tool was designed to study the characteristics of variable bit rate video sources for transmission over asynchronous transfer mode (ATM) based broadband integrated services digital network (B-ISDN). The tool, which has a window-based graphic user interface, allows a user to specify several of the MPEG parameters such as the intraframe-to-interframe ratio and the quantizer scale. The tool also includes a statistical package that allows the user to plot graphs of various statistics including bit distributions, ATM cell distributions, time se ries, autocorrelation functions and cell interarrival times.This work was supported in part by grant NCR 90-16165 from the National Science Foundation     

Positive transfer and negative transfer/antilearning of problem-solving skills.

In problem-solving research, insights into the relationship between monitoring and control in the transfer of complex skills remain impoverished. To address this, in 4 experiments, the authors had participants solve 2 complex control tasks that were identical in structure but that varied in presentation format. Participants learned to solve the 2nd task on the basis of their original learning phase from the 1st task or learned to solve the 2nd task on the basis of another participant's learning phase. Experiment 1 showed that, under conditions in which the participant's learning phase was experienced twice, performance deteriorated in the 2nd task. In contrast, when the learning phases in the 1st and 2nd tasks differed, performance improved in the 2nd task. Experiment 2 introduced instructional manipulations that induced the same response patterns as those in Experiment 1. In Experiment 3, further manipulations were introduced that biased the way participants evaluated the learning phase in the 2nd task. In Experiment 4, judgments of self-efficacy were shown to track control performance. The implications of these findings for theories of complex skill acquisition are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural and Wavelet Network Models for Financial Distress Classification

This work analyzes the use of linear discriminant models, multi-layer perceptron neural networks and wavelet networks for corporate financial distress prediction. Although simple and easy to interpret, linear models require statistical assumptions that may be unrealistic. Neural networks are able to discriminate patterns that are not linearly separable, but the large number of parameters involved in a neural model often causes generalization problems. Wavelet networks are classification models that implement nonlinear discriminant surfaces as the superposition of dilated and translated versions of a single “mother wavelet” function. In this paper, an algorithm is proposed to select dilation and translation parameters that yield a wavelet network classifier with good parsimony characteristics. The models are compared in a case study involving failed and continuing British firms in the period 1997–2000. Problems associated with over-parameterized neural networks are illustrated and the Optimal Brain Damage pruning technique is employed to obtain a parsimonious neural model. The results, supported by a re-sampling study, show that both neural and wavelet networks may be a valid alternative to classical linear discriminant models.     

Relationship between observational accuracy and accuracy in evaluating performance.

Examined relationships among components of accuracy in tasks of performance rating and observational accuracy. Measures of elevation, differential elevation, stereotype accuracy, and differential accuracy were obtained in a teacher rating task. 44 undergraduates viewed videotapes of 4 graduate student lecturers and rated each using the Frequency Rating scale to measure accuracy in behavioral observation, as well as standard teacher evaluation forms (the Performance Evaluation scale). Measures of elevation, differential elevation, and differential accuracy in rating the frequency of behaviors previously defined as critical incidents were related to corresponding measures of accuracy in evaluating performance. Data suggest that accuracy in observing or evaluating performance is not a generalized ability, but different types of accuracy are independent. Frequency ratings are tied to specific behaviors chosen on the basis of clarity and relevance, while performance evaluation requires complex, abstract judgments about performance quality. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)