Neural nets - their use and abuse for small data sets

Neural nets can be used for non-linear classification and regression models. They have a big advantage over conventional statistical tools in that it is not necessary to assume any mathematical form for the functional relationship between the variables. However, they also have a few associated problems chief of which are probably the risk of over-parametrization in the absence of P-values, the lack of appropriate diagnostic tools and the difficulties associated with model interpretation. The first of these problems is particularly important in the case of small data sets. These problems are investigated in the context of real market research data involving non-linear regression and discriminant analysis. In all cases we compare the results of the non-linear neural net models with those of conventional linear statistical methods. Our conclusion is that the theory and software for neural networks has some way to go before the above problems will be solved

Rating Forecasts for Television Programs

This paper investigates the effect of aggregation and non-linearity in relation to television rating forecasts. Several linear models for aggregated and disaggregated television viewing have appeared in the literature. The current analysis extends this work using an empirical approach. We compare the accuracy of population rating models, segment rating models and individual viewing behaviour models. Linear and non-linear models are fitted using regression, decision trees and neural networks, with a two-stage procedure being used to model network choice and viewing time for the individual viewing behaviour model. The most accurate forecast results are obtained from the non-linear segment rating models.Decision Trees, Disaggregation, Discrete Choice Models, Neural Networks, Rating Benchmarks

The Study of tone and related phenomena in an Amazonian tone language: Gavião of Rondônia

This paper describes the methods used to study the tone and some related phenomena of the language of the Gavião of Rondônia, Brazil, which is part of the Mondé branch of the Tupi family. Whistling of words by indigenous informants was discovered to be a very effective method for obtaining phonetic accuracy in tone and length. Methods were devised to map out the system of tone and length. They were subsequently used in the study of other Amazonian languages, including Karitiana, Munduruku, Zoró, and Surui of Rondônia, with success. Some notes on tone considerations in orthography are offered, as well as notes on procedures that proved useful in the diachronic study of tone in the Mondé languages. Methods for the study of natural whistled speech used for distance communication are also described, with special attention to the whistled speech of the Gavião, including its use, its efficiency, and the whistling techniques used. The relation between some aspects of Gavião instrumental music and the suprasegmental aspects of the language are also discussed and the methods used to study this are described. Audio and video clips illustrate the phenomena being discussed. *This paper is in the series How to Study a Tone Language, edited by Steven Bird and Larry HymanNational Foreign Language Resource Cente

Adherence to traditional Indian customs surrounding birth

Customs traditionally followed by Indian women during pregnancy, birth and early parenthoodhave been documented. An exploratory investigation of the extent to which some of these traditional beliefs, customs and practices are currently adhered to was undertaken by interviewing Indian mothers living in Johannesburg and its environs about 3 months after delivery. Results indicate that while some traditional customs are still adhered to by most Indian women, others are not so strictly followed. Since most customs relate to activities conducted at home rather than while in hospital for delivery, medical care would not be expected to influence their practice

Modelling the role of intrapreneurial strategy-making in small firm performance

Intrapreneurs are those employees who identify and pursue opportunities in a firm. By pursuing these opportunities with new products, services or processes, intrapreneurial employees may influence the strategic direction of the firm, a process called intrapreneurial strategy-making. Little consideration has been given to how small firms may use this process to improve performance. To this end this paper describes the results of an empirical study conducted with 454 small firms. Analysis of the data indicates that intrapreneurial strategy-making has a significant positive relationship with firm performance, depending on the size of the firm, its organizational structure and the dynamism of the environment. It further shows that differentiation strategies may mediate this relationship

Calculating Chemical Evolution on the Web

We have constructed a web site that may be of interest to cosmochemists seeking to under-stand the evolution of isotopes in the Galaxy. The URL is http://photon.phys.clemson.edu/gce.html. It is fully interactive and uses IDL on the Net (ION) to construct tables and graphs dynamically. The resulting tables may be downloaded as text files while the graphs may be downloaded as gif or postscript files. The present ab-stract presents a brief tutorial on using the “GCE tool” on this site and illustrates some of its capabilities. Ques-tions or comments should be addressed to either of the first two authors

The Impact of Gender and Pedagogical Factors on Female Pass Rates

An assessment of student achievement according to gender in core units of study of a Faculty of Information and Communication Technology program tested four hypotheses. The first of these related to the role-model effect of female academics; the second related to the advantages of formal education qualifications of academics; the third to the application of contextualized curricula, and the fourth to the use of a variety of assessment modes. Correlation and regression analysis on the data set indicated that the presence of two of these factors can significantly improve the pass rate of female students while having a benign effect on the pass rate of male students. It is suggested that information systems faculties pay close attention to gender diversity of their teaching faculty, particularly if their female student cohort is less than one in five in a unit of study. It also gives substance to the need or preference for university lecturers having education qualifications. This study needs to be replicated in other information systems faculties and schools to verify this finding

The diagnostic validity and reliability of an internet-based clinical assessment program for mental disorders

BACKGROUND: Internet-based assessment has the potential to assist with the diagnosis of mental health disorders and overcome the barriers associated with traditional services (eg, cost, stigma, distance). Further to existing online screening programs available, there is an opportunity to deliver more comprehensive and accurate diagnostic tools to supplement the assessment and treatment of mental health disorders. OBJECTIVE: The aim was to evaluate the diagnostic criterion validity and test-retest reliability of the electronic Psychological Assessment System (e-PASS), an online, self-report, multidisorder, clinical assessment and referral system. METHODS: Participants were 616 adults residing in Australia, recruited online, and representing prospective e-PASS users. Following e-PASS completion, 158 participants underwent a telephone-administered structured clinical interview and 39 participants repeated the e-PASS within 25 days of initial completion. RESULTS: With structured clinical interview results serving as the gold standard, diagnostic agreement with the e-PASS varied considerably from fair (eg, generalized anxiety disorder: &kappa;=.37) to strong (eg, panic disorder: &kappa;=.62). Although the e-PASS\u27 sensitivity also varied (0.43-0.86) the specificity was generally high (0.68-1.00). The e-PASS sensitivity generally improved when reducing the e-PASS threshold to a subclinical result. Test-retest reliability ranged from moderate (eg, specific phobia: &kappa;=.54) to substantial (eg, bulimia nervosa: &kappa;=.87). CONCLUSIONS: The e-PASS produces reliable diagnostic results and performs generally well in excluding mental disorders, although at the expense of sensitivity. For screening purposes, the e-PASS subclinical result generally appears better than a clinical result as a diagnostic indicator. Further development and evaluation is needed to support the use of online diagnostic assessment programs for mental disorders. <br /

Study protocol for a randomised controlled trial of internet-based cognitive-behavioural therapy for obsessive-compulsive disorder

BACKGROUND Obsessive-Compulsive Disorder (OCD) is a common chronic psychiatric disorder that constitutes a leading cause of disability. Although Cognitive-Behaviour Therapy (CBT) has been shown to be an effective treatment for OCD, this specialised treatment is unavailable to many due to access issues and the social stigma associated with seeing a mental health specialist. Internet-based psychological treatments have shown to provide effective, accessible and affordable treatment for a range of anxiety disorders, and two Randomised Controlled Trials (RCTs) have demonstrated the efficacy and acceptability of internet-based CBT (iCBT) for OCD, as compared to waitlist or supportive therapy. Although these initial findings are promising, they do not isolate the specific effect of iCBT. This paper details the study protocol for the first randomised control trial evaluating the efficacy of therapist-assisted iCBT for OCD, as compared to a matched control intervention; internet-based therapist-assisted progressive relaxation training (iPRT). It will aim to examine whether therapist-assisted iCBT is an acceptable and efficacious treatment, and to examine how effectiveness is influenced by patient characteristics. METHOD/DESIGN A randomised controlled trial using repeated measures with two arms (intervention and matched control) will be used to evaluate the efficacy and acceptability of iCBT for OCD. The RCT will randomise 212 Australian adults with a primary diagnosis of OCD into either the active intervention or control condition, for 12 weeks duration. Outcomes for participants in both study arms will be assessed at baseline and post-intervention. Participants in iCBT will be further assessed at six month follow-up, while participants in the control condition will be crossed over to receive the iCBT intervention and reassessed at post-intervention and six month follow-up. The primary outcome will be clinically significant change in obsessive-compulsive symptom scores. DISCUSSION This will be the first known therapist assisted internet-based trial of a comprehensive CBT treatment for OCD as compared to a matched control intervention. Demonstrating the efficacy of an internet-based treatment for OCD will allow the development of models of care for broad-based access to an evidence-based but complex treatment.Research funded by the NHMRC (Project Grant 620506) awarded to Kyrios, M., Nedeljkovic, M., Moulding, R., Klein, B. & Austin, D