The traditional approach to AI is limited because it fails to exploit continuity. The reliance on discrete logic has allowed the rapid initial advance of the subject, but constitutes an inherent deficiency. The limitations have become apparent, and are generally acknowledged by a revival of interest in neural‐net, or connectionist, techniques. This approach has become feasible because of technical developments allowing large‐scale parallel operation. Lessons can be learned by considering the evolution of natural intelligence. Recent studies from a biological viewpoint suggest that this has some unexpected features. The idea of concept formation should be extended to include quantifiable concepts, similar to the semantic variables of fuzzy set theory.
Children experience toxic stress if there is pronounced activation of their stress-response systems, in situations in which they do not have stable caregiving. Due to…
Children experience toxic stress if there is pronounced activation of their stress-response systems, in situations in which they do not have stable caregiving. Due to their exposure to multiple poverty-related risks, African American children may be more susceptible to exposure to toxic stress. Toxic stress affects young children’s brain and neurophysiologic functioning, which leads to a wide range of deleterious health, developmental, and mental health outcomes. Given the benefits of early care and education (ECE) for African American young children, ECE may represent a compensating experience for this group of children, and promote their positive development.
Interest in car-sharing initiatives, as a tool for improving transport network efficiency in urban areas and on interurban links, has grown in recent years. They have…
Interest in car-sharing initiatives, as a tool for improving transport network efficiency in urban areas and on interurban links, has grown in recent years. They have often been proposed as a more cost effective alternative to other modal shift and congestion relief initiatives, such as public transport or highway improvement schemes; however, with little implementation in practice, practitioners have only limited evidence for assessing their likely impacts.
This study reports the findings of a Stated Preference (SP) study aimed at understanding the value that car drivers put on car sharing as opposed to single occupancy trips. Following an initial pilot period, 673 responses were received from a web-based survey conducted in June 2008 amongst a representative sample of car driving commuters in Scotland.
An important methodological aspect of this study was the need to account for differences in behaviour to identify those market segments with the greatest propensity to car share. To this end, we estimated a range of choice model forms and compared the ability of each to consistently identify individual behaviours. More specifically, this included a comparison of:
Standard market segmentation approaches based on multinomial logit with attribute coefficients estimated by reported characteristics (e.g. age, income, etc.);
A two-stage mixed logit approach involving the estimation of random parameters logit models followed by an examination of individual respondent's choices to arrive at estimates of their parameters, conditional on know distributions across the population (following Revelt & Train, 1999); and
A latent-class model involving the specification of C classes of respondent, each with their own coefficients, and assigning each individual a probability that they belongs to a given class based upon their observed choices, socioeconomic characteristics and their reported attitudes.
As hypothesised, there are significant variations in tastes and preferences across market segments, particularly for household car ownership, gender, age group, interest in car pooling, current journey time and sharing with a stranger (as opposed to family member/friend). Comparing the sensitivity of demand to a change from a single occupancy to a car-sharing trip, it can be seen that the latter imposes a ‘penalty’ equivalent to 29.85 IVT minutes using the mixed logit structure and 26.68 IVT minutes for the multinomial specification. Segmenting this latter value according to the number of cars owner per household results in ‘penalties’ equivalent to 46.51 and 26.42 IVT minutes for one and two plus car owning households respectively.
Ranked preference data arise when a set of judges rank, in order of their preference, a set of objects. Such data arise in preferential voting systems and market research…
Ranked preference data arise when a set of judges rank, in order of their preference, a set of objects. Such data arise in preferential voting systems and market research surveys. Covariate data associated with the judges are also often recorded. Such covariate data should be used in conjunction with preference data when drawing inferences about judges.
To cluster a population of judges, the population is modeled as a collection of homogeneous groups. The Plackett-Luce model for ranked data is employed to model a judge's ranked preferences within a group. A mixture of Plackett- Luce models is employed to model the population of judges, where each component in the mixture represents a group of judges.
Mixture of experts models provide a framework in which covariates are included in mixture models. Covariates are included through the mixing proportions and the component density parameters. A mixture of experts model for ranked preference data is developed by combining a mixture of experts model and a mixture of Plackett-Luce models. Particular attention is given to the manner in which covariates enter the model. The mixing proportions and group specific parameters are potentially dependent on covariates. Model selection procedures are employed to choose optimal models.
Model parameters are estimated via the ‘EMM algorithm’, a hybrid of the expectation–maximization and the minorization–maximization algorithms. Examples are provided through a menu survey and through Irish election data. Results indicate mixture modeling using covariates is insightful when examining a population of judges who express preferences.
THE scientist and philosopher will tell us that the mind of man cannot in a lifetime fully grasp and understand any one subject. Consequently it is unreasonable to expect that the librarian—who, in spite of popular belief, is but man—can have a complete understanding of every department of knowledge relative to his work. He must, in common with his fellows in other callings, content himself with a more or less general professional knowledge, and may specialize, if he be so disposed, in certain branches of that knowledge. The more restricted this particular knowledge is, the greater will be its value from a specialistic point of view.
Looks at the 2000 Employment Research Unit Annual Conference held at the University of Cardiff in Wales on 6/7 September 2000. Spotlights the 76 or so presentations within and shows that these are in many, differing, areas across management research from: retail finance; precarious jobs and decisions; methodological lessons from feminism; call centre experience and disability discrimination. These and all points east and west are covered and laid out in a simple, abstract style, including, where applicable, references, endnotes and bibliography in an easy‐to‐follow manner. Summarizes each paper and also gives conclusions where needed, in a comfortable modern format.
Surveys of offender treatment programmes have revealed that practitioners delivering specialist programmes are often unaware of much of the theoretical and research…
Surveys of offender treatment programmes have revealed that practitioners delivering specialist programmes are often unaware of much of the theoretical and research literature behind the interventions they deliver. For practitioners working less routinely with offenders, such as forensic nurses, this problem is likely to be more acute. In this paper, we provide a general overview of the theoretical and research literature relevant to programmes targeting sexual and aggressive offending that should be of interest to a range of professionals working with offenders in different clinical settings.
“GIVE a dog a bad name and hang him,” is an aphorism which has been accepted for many years. But, like many other household words, it is not always true. Even if it were, the dog to be operated upon would probably prefer a gala day at his Tyburn Tree to being executed in an obscure back yard.