Grammar-based Genetic Programming: a survey

Grammar formalisms are one of the key representation structures in Computer Science. So it is not surprising that they have also become important as a method for formalizing constraints in Genetic Programming (GP). Practical grammar-based GP systems first appeared in the mid 1990s, and have subsequently become an important strand in GP research and applications. We trace their subsequent rise, surveying the various grammar-based formalisms that have been used in GP and discussing the contributions they have made to the progress of GP. We illustrate these contributions with a range of applications of grammar-based GP, showing how grammar formalisms contributed to the solutions of these problems. We briefly discuss the likely future development of grammar-based GP systems, and conclude with a brief summary of the field.     

Mutation analysis for prenatal diagnosis of hereditary tyrosinaemia type 1

Presentation of 11 cases of retroperitoneal sarcoma. Mean time from the beginning of symptoms to diagnosis is 6 months. The primary complementary study is CT. Surgery was performed in all cases, using complete resection in 6 cases, and partial resection in 5. Ten patients relapsed. 9 of which were treated with surgical rescue, in one or more occasions; chemotherapy was added in 6 cases and radiotherapy in 7. Survival at five years is 68%, with a mean follow-up of 66 months.     

Diagnostic accuracy of a rural live video telepathology system

Accuracy of diagnoses rendered using a live video telepathology network was assessed for permanent sections of surgical pathology specimens. To determine accuracy, telepathology diagnoses were compared with those obtained by directly viewing the glass slide using a standard microscope. A total of 294 cases were read via both telepathology and glass slide by attending pathologists at a tertiary care medical center. Overall accuracy was defined as exact concordance between diagnoses. Clinically insignificant differences in diagnoses were excluded to determine clinically significant accuracy. For the 285 cases with complete data, the overall accuracy for telepathology was 0.912 (95% confidence interval [CI], 0.872-0.941), whereas the overall accuracy for glass slide readings was 0.968 (95% CI, 0.939-0.985). This difference is statistically significant (p = 0.009). When focusing on clinically significant discrepancies, where the difference in diagnosis might affect therapeutic decisions, the video accuracy was only slightly less than the glass slide accuracy (0.965 [95% CI, 0.934-0.982] vs. 0.982 [95% CI, 0.957-0.994], respectively), but this difference is not statistically significant (p = 0.302). Most of the cases with clinically significant differences involved lesions with inherently high interobserver variation. Certainty of diagnosis did not differ between video and glass slide readings (p = 0.911), but there was an association between certainty of diagnosis and diagnostic accuracy for video (p = 0.003 for clinically significant accuracies). Based on these findings, we recommend when using this telepathology system that only preliminary diagnoses should be given in the following situations: for diagnostic areas with known high interobserver variability; when the consultant has any degree of uncertainty about the presence or absence of the lesion in question; and when there is insufficient experience using telepathology as a diagnostic medium.     

ANALYSIS OF ORGANIC MATERIAL DIFFICULT TO RECOVER FROM OIL SHALE

Green River oil shale was supercritically treated with methanol and water and then extracted with benzene and methanol to recover approximately 85% of the organic matter in the shale. The spent shale was then extracted with pyridine to recover an additional 2-31% of the organic matter that remained on the shale. The liquid organic material extracted with pyridine contained some of the compound types most difficult to recover from shale. These materials were characterized. High-molecular nitrogen compounds of the pyridine type were found to be a predominant compound class in the pyridine extract. The pyridine-extracted material contained a higher percentage of nitrogen than a Fischer assay oil and a lower percentage of hydrogen than a Fischer assay oil indicating that more aromatic nitrogen compounds were present in the pyridine extract than in Fischer assay oil. Bonding mechanisms between organic and inorganic components of the shale were studied as were spectroscopic data showing the nature of the organic material remaining on spent shale after extraction with pyridine.     

Roles of Levies for Sustainable Domestic Water Consumption

Sustainable development is the modern rhetoric to guide environmental or natural resources management. There are many ways to do this and one is the wider utilization of economic instruments, such as taxes and levies. Although such levies are becoming common in Australia and worldwide, the role of the taxes or levies is still limited. In many cases, these taxes/levies -although environmentally related- have a fiscal rather than a purely environmental motive, for example, the Natural Resources Management (NRM) Levy in South Australia. This study evaluates the NRM levy policy using one NRM region and focussing on the Adelaide urban community. Data was collected through a web-based survey with 770 respondents who answered 59 questions. The research found that community strongly prefers a levy calculated on the volume of water consumed. Respondents also indicated that they would use less water if the levy were calculated on the volume of water consumed. The clear implications of the results suggest that if a tax or levy aims to change water consumption behaviour then it should be based on the volume of water consumed not on property value.     

Mediators of telephone-based continuing care for alcohol and cocaine dependence.

A previous randomized trial with 224 alcohol and/or cocaine addicts who had completed an initial phase of treatment indicated that 12 weeks of telephone-based continuing care yielded higher abstinence rates over 24 months than did group counseling continuing care. The current study examined mediators of this treatment effect. Results suggested that self-help involvement during treatment and self-efficacy and commitment to abstinence 3 months after treatment mediated subsequent abstinence outcomes. These analyses controlled for substance use prior to the assessment of mediators. Conversely, there was no evidence that self-help beliefs or social support mediated the treatment effect. These results are consistent with a model in which treatment effects are first accounted for by changes in behavior, followed by changes in self-efficacy and in commitment to abstinence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)