Genetic programming: the ratio of crossover to mutation as a function of time

This article studies the sub-tree operators: mutation and crossover, within the context of Genetic Programming. Two standard problems, symbolic linear regression and a non-linear tree, were presented to the algorithm at each stage. The behaviour of the operators in regard to fitness is first established, followed by an analysis of the most optimal ratio between crossover and mutation. Subsequently, three algorithms are presented as candidates to dynamically learn the most optimal level of this ratio. The results of each algorithm are then compared to each other and the traditional constant ratio

Why Don't Women Patent?

We investigate women's underrepresentation among holders of commercialized patents: only 5.5% of holders of such patents are female. Using the National Survey of College Graduates 2003, we find only 7% of the gap is accounted for by women's lower probability of holding any science or engineering degree, because women with such a degree are scarcely more likely to patent than women without. Differences among those without a science or engineering degree account for 15%, while 78% is accounted for by differences among those with a science or engineering degree. For the latter group, we find that women's underrepresentation in engineering and in jobs involving development and design explain much of the gap; closing it would increase U.S. GDP per capita by 2.7%.

Giant pop-ins and amorphization in germanium during indentation

Sudden excursions of unusually large magnitude (>1 μm), “giant pop-ins,” have been observed in the force-displacement curve for high load indentation of crystalline germanium(Ge). A range of techniques including Raman microspectroscopy, focused ion-beam cross sectioning, and transmission electron microscopy, are applied to study this phenomenon. Amorphous material is observed in residual indents following the giant pop-in. The giant pop-in is shown to be a material removal event, triggered by the development of shallow lateral cracks adjacent to the indent. Enhanced depth recovery, or “elbowing,” observed in the force-displacement curve following the giant pop-in is explained in terms of a compliant response of plates of material around the indent detached by lateral cracking. The possible causes of amorphization are discussed, and the implications in light of earlier indentation studies of Ge are considered

Isolation and integration in education

ArticleMS201

A stochastic infilling algorithm for spatial-temporal rainfall data : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Statistics at Massey University

CD unreadableThe purpose of this thesis is to develop an infilling algorithm for 24-hour (daily) rainfall data. An infilling algorithm replaces missing data within the historical records with sensible estimates, where any appropriate method (prediction from a fitted model, interpolation between points, or random sampling) could be used to select and/or produce the required estimates. The algorithm developed uses simulation data generated using a stochastic point-process model which has been fitted to historical data. In this thesis, the spatial-temporal Neyman-Scott rectangular pulse model as presented in Cowpertwait et al. (2002) is fitted to data provided by Thames Water from 23 sites in the Thames Valley (UK). The model is shown to fit the data reasonably well; however it fails to fit the proportion of dry sites (which is not used in the fitting process). Nevertheless, simulated data is generated using the model and an infilling algorithm is derived. The algorithm is tested by replacing valid historical data with missing values, infilling these missing values, and then comparing relevant statistics for the two samples. Three algorithms are developed in this thesis, of which the final algorithm maintains the statistical characteristics of the historical data, including the proportion of dry sites, while infilling values that are similar to the known historical record

The First Provenance Challenge

The first Provenance Challenge was set up in order to provide a forum for the community to help understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a Functional Magnetic Resonance Imaging workflow was defined, which participants had to either simulate or run in order to produce some provenance representation, from which a set of identified queries had to be implemented and executed. Sixteen teams responded to the challenge, and submitted their inputs. In this paper, we present the challenge workflow and queries, and summarise the participants contributions

Essays on Government Policy in Real Estate Markets

This dissertation uses administrative data to study regulatory issues in the American real estate market. The first chapter studies spillovers from home foreclosures in Cook County, Illinois. Random assignment of foreclosure cases to judges allows for estimation of the causal effect of foreclosure (relative to a foreclosure case being dismissed) on neighboring foreclosure filings and housing transactions. When a property forecloses, the local housing market is disrupted--prices fall and more lower quality homes sell--and neighbors are more likely to end up in default and going through the foreclosure process. The second chapter examines how discontinuously applied transfer taxes distort the mar- ket for real estate sales in New York and New Jersey. These transfer taxes distort not only the price of real estate transactions that occur near the discontinuity, corresponding to sellers bearing the entire incidence of the tax, but also the volume of sales that occur--productive transactions that would occur if the tax were not discontinuous disappear from the market. The third and final chapter estimates the market-level response of home equity loans to two discontinuous mortgage policies--the home mortgage interest deduction, and real estate appraisal regulations in the Financial Institutions Reform Recovery and Enforcement Act. The estimates therein imply that home equity debt is very responsive to both the after-tax interest rate as well as lender underwriting requirements

Sense of agency and mentalizing: Dissociation of subdomains of social cognition in patients with schizophrenia

The sense of agency, i.e., the sense that “I am the one who is causing an action”, and mentalizing, the ability to understand the mental states of other individuals, are key domains of social cognition. It has been hypothesized that an intact sense of agency is an important precondition for higher-level mentalizing abilities. A substantial body of evidence shows that both processes rely on similar brain areas and are severely impaired in schizophrenia, suggesting a close link between agency and mentalizing. Yet this relationship has not been explicitly tested. We investigated 40 individuals with schizophrenia and 40 healthy controls on an agency and mentalizing task. On the agency task, participants carried out simple mouse movements and judged the partially manipulated visual feedback as either self- or other-generated. On the mentalizing task, participants inferred mental states from pictures that depicted others' eyes (“Reading the mind in the eyes test”). Neuropsychological, psychopathological and social functioning levels were also evaluated. Both sense of agency and mentalizing were impaired in schizophrenia patients compared to healthy controls. However, testing for a relationship revealed no significant correlations between the two processes, either in the schizophrenia or the control group. The present findings demonstrate a dissociation of agency and mentalizing deficits in schizophrenia, suggesting that the multifaceted construct of social cognition consists of independent subdomains in healthy and psychiatrically ill individuals