Evaluation of Tweedie exponential dispersion model densities by Fourier inversion

The Tweedie family of distributions is a family of exponential dispersion models with power variance functions V (μ) = μ^p for p not between (0, 1). These distributions do not generally have density functions that can be written in closed form. However, they have simple moment generating functions, so the densities can be evaluated numerically by Fourier inversion of the characteristic functions. This paper develops numerical methods to make this inversion fast and accurate. Acceleration techniques are used to handle oscillating integrands. A range of analytic results are used to ensure convergent computations and to reduce the complexity of the parameter space. The Fourier inversion method is compared to a series evaluation method and the two methods are found to be complementary in that they perform well in different regions of the parameter space

East Java: Cenozoic basins, volcanoes and ancient basement

East Java on land is divided here into four broadly EW zones: (1) the Southern Mountains Zone, an Eocene to Miocene volcanic arc, separated by (2) the present-day volcanic arc from (3) the Kendeng Zone which was the main Cenozoic depocentre in onshore East Java; and to the north (4) the Rembang Zone which represents the edge of the Sunda Shelf. Several synthems separated by unconformities can be identified and correlated between the different zones. There is a regional angular unconformity above Upper Cretaceous and older basement. The oldest rocks above the unconformity range from Mid Eocene to Lower Oligocene and record a gradual transgression and, in SE Java, an increase in volcanic material up-section.After an intra-Oligocene sea-level fall, volcanic material from the arc dominated in the Southern Mountains and Kendeng Zones while in the Rembang Zone carbonate deposition continued. In the Early Miocene, activity in the Southern Mountains Volcanic Arc culminated in a major eruptive phase at 20 Ma ± 1 Ma, similar in scale to the Pleistocene eruptions of Toba. To the north carbonate deposition was interrupted by clastic input containing reworked basement and Eocene material. The Mid Miocene was a period of reworking and carbonate sedimentation. In the Late Miocene volcanic activity recommenced at the position of the present-day arc and there was a series of deformation events throughout East Java. Volcanism has played an important role in the development of East Java, providing a source of material and contributing to subsidence by flexural loading. Provenance studies and dating of zircons provide insight into the basement character and suggest that continental crust of Gondwana (possibly Western Australian) origin lies beneath part of the Southern Mountains Zone. It is suggested that continental Sundaland provided very little, if any, terrigenous material to East Java in the Cenozoic

The impacts of replacing air bubbles with microspheres for the clarification of algae from low cell-density culture

Dissolved Air Flotation (DAF) is a well-known coagulation–flotation system applied at large scale for microalgae harvesting. Compared to conventional harvesting technologies DAF allows high cell recovery at lower energy demand. By replacing microbubbles with microspheres, the innovative Ballasted Dissolved Air Flotation (BDAF) technique has been reported to achieve the same algae cell removal efficiency, while saving up to 80% of the energy required for the conventional DAF unit. Using three different algae cultures (Scenedesmus obliquus, Chlorella vulgaris and Arthrospira maxima), the present work investigated the practical, economic and environmental advantages of the BDAF system compared to the DAF system. 99% cells separation was achieved with both systems, nevertheless, the BDAF technology allowed up to 95% coagulant reduction depending on the algae species and the pH conditions adopted. In terms of floc structure and strength, the inclusion of microspheres in the algae floc generated a looser aggregate, showing a more compact structure within single cell alga, than large and filamentous cells. Overall, BDAF appeared to be a more reliable and sustainable harvesting system than DAF, as it allowed equal cells recovery reducing energy inputs, coagulant demand and carbon emissions

Capable environments

Purpose: To outline the role played by different aspects of the social, physical and organisational environments in preventing behaviour described as challenging in people with learning disabilities. Design/methodology/approach: Conceptual elaboration drawing on research and practice literature. Findings: Community placements for people with learning disabilities should develop the characteristics of capable environments. Such characteristics are associated with prevention of challenging behaviour and improved quality of life outcomes. Originality/value: The notion of the capable environment may help to shift the focus from the individual who displays behaviour described as challenging to the characteristics of the social, physical and organisational supports that they receive

Experiments in terabyte searching, genomic retrieval and novelty detection for TREC 2004

In TREC2004, Dublin City University took part in three tracks, Terabyte (in collaboration with University College Dublin), Genomic and Novelty. In this paper we will discuss each track separately and present separate conclusions from this work. In addition, we present a general description of a text retrieval engine that we have developed in the last year to support our experiments into large scale, distributed information retrieval, which underlies all of the track experiments described in this document