Explaining point variability in the eastern Victoria river region, northern territory

This paper constructs a reduction sequence model for north Australian points from the eastern Victoria River region, and identifies a single continuum linking unifacial and bifacial point forms, with some divergence from this single reduction trajectory dependent upon artefact size. Chronological changes in reduction intensity between 5,000BP and the present are found to coincide with typological variation in points as well as changing emphasis on the extendibility of point reduction. It is suggested that changes in the extendibility of point reduction can be linked to intensified ENSO-driven climatic variability in the late Holocene that likely increased economic risk and warranted a substantial technological response, including the use of retouched toolkits with potential for longer use-lives.

A modified particle filter for simultaneous robot localization and landmark tracking in an indoor environment

This paper presents the implementation of a modified particle filter for vision-based simultaneous localization and mapping of an autonomous robot in a structured indoor environment. Through this method, artificial landmarks such as multi-coloured cylinders can be tracked with a camera mounted on the robot, and the position of the robot can be estimated at the same time. Experimental results in simulation and in real environments show that this approach has advantages over the extended Kalman filter with ambiguous data association and various levels of odometric noise.

Formal verification of ASM designs using the MDG tool

In this paper, we present a formal hardware verification framework linking ASM with MDG. ASM (Abstract State Machine) is a state based language for describing transition systems. MDG (Multiway Decision Graphs) provides symbolic representation of transition systems with support of abstract sorts and functions. We implemented a transformation tool that automatically generates MDG models from ASM specifications, then formal verification techniques provided by the MDG tool, such as model checking or equivalence checking, can be applied on the generated models. We support this work with a case study of an Island Tunnel Controller, which behavior and structure were specified in ASM then using our ASM-MDG tool successfully verified within the MDG tool.

Compositional verification for object-Z

This paper presents a framework for compositional verification of Object-Z specifications. Its key feature is a proof rule based on decomposition of hierarchical Object-Z models. For each component in the hierarchy local properties are proven in a single proof step. However, we do not consider components in isolation. Instead, components are envisaged in the context of the referencing super-component and proof steps involve assumptions on properties of the sub-components. The framework is defined for Linear Temporal Logic (LTL)

Interfacing ASM with the MDG tool

In this paper we describe an approach to interface Abstract State Machines (ASM) with Multiway Decision Graphs (MDG) to enable tool support for the formal verification of ASM descriptions. ASM is a specification method for software and hardware providing a powerful means of modeling various kinds of systems. MDGs are decision diagrams based on abstract representation of data and axe used primarily for modeling hardware systems. The notions of ASM and MDG axe hence closely related to each other, making it appealing to link these two concepts. The proposed interface between ASM and MDG uses two steps: first, the ASM model is transformed into a flat, simple transition system as an intermediate model. Second, this intermediate model is transformed into the syntax of the input language of the MDG tool, MDG-HDL. We have successfully applied this transformation scheme on a case study, the Island Tunnel Controller, where we automatically generated the corresponding MDG-HDL models from ASM specifications.

Upper Devonian biostratigraphy of the Iberian Pyrite Belt, southwest Spain Part Two: Organic-walled microphytoplankton

Upper Devonian rocks of the Iberian Pyrite Belt (IPB) in southwest Spain, comprising the Phyllite-Quartzite Group (PQ) and the lower part of the overlying Volcano-Sedimentary Complex (VSC), contain a diversity of terrestrial and marine palynomorphs (miospores and organic-walled microphytoplankton, respectively), which constitute the basis of this biostratigraphically oriented research project. Part One of the report has previously detailed the miospore content of the constituent 117 palyniferous samples. In the present paper (i.e., the concluding Part Two), the organic-walled microphytoplankton (acritarchs and prasinophyte phycomata) are systematically described and illustrated, and their occurrence in the study material is fully documented. The acritarchs are represented by 23 species (including one species complex) allocated among 14 genera (one of which, Dupliciradiatum, is newly established), together with a very rare and novel category (informally termed Gen. nov. A). The following new acritarch species are formally instituted: Dupliciradiatum crassum (type species), D. tenue, Histopalla languida, and Winwaloeusia repagulata. Five genera allied with the prasinophycean algae are identified; these accommodate a total of 15 species of which two - Cymatiosphaera tenuimembrana and Maranhites multioculus - are formally proposed as new. In addition, representatives of the prasinophyte genera Leiosphaeridia and Tasmanites are recorded but are not discriminated at species level. The microphytoplankton suite is clearly consonant, from previously published occurrences in other regions, with a Late Devonian dating. However, most of the species are known to be relatively long ranging through (and in some cases beyond) that epoch and hence are not amenable to detailed biozonal subdivision of the IPB succession. Moreover, the distribution of the species therein tends to be erratic in comparison with the more consistently occurring miospores, possibly due to stress factors induced by fluctuating conditions in the IPBs Upper Devonian marine environment. By contrast, the land-derived (miospore) assemblages are readily applicable in a blostratigraphic context: they can be correlated precisely with the Devonian miospore biozonation scheme for Western Europe. In those terms, the sampled PQ strata are assignable to the Diducites versabilis-Grandispora cornuta (VCo) Biozone of late Famennian age; while the samples from the anoxic sequence at the base of the VSC belong to the Retispora lepidophyta-Verrucosisporites nitidus (LN) Biozone (latest Famennian = latest Devonian). The biochronostratigraphic data, in conjunction with the findings from earlier IPB studies, imply two appreciable palynostratigraphic breaks within the PQ. These are representative, respectively, of the lower Frasnian-middle Famennian interval and of part of the Strunian/upper Famennian. Speculation currently remains as to whether the inferred gaps are more apparent than real; i.e., whether one or both represent actual hiatuses in IPB sedimentation or are simply a manifestation of hitherto unsampled and/or non-palyniferous PQ strata.

Early practical experience and the social responsiveness of clinical education: Systematic review

Objectives To find how early experience in clinical and community settings (early experience) affects medical education, and identify strengths and limitations of the available evidence. Design A systematic review rating, by consensus, the strength and importance of outcomes reported in the decade 1992-2001. Data sources Bibliographical databases and journals were searched for publications on the topic, reviewed under the auspices of the recently formed Best Evidence Medical Education (BEME) collaboration. Selection of studies All empirical studies (verifiable, observational data) were included, whatever their design, method, or language of publication. Results Early experience was most commonly provided in community settings, aiming to recruit primary care practitioners for underserved populations. It increased the popularity of primary care residencies, albeit among self selected students. It fostered self awareness and empathic attitudes towards ill people, boosted students' confidence, motivated them, gave them satisfaction, and helped them develop a professional identity. By helping develop interpersonal skills, it made entering clerkships a less stressful experience. Early experience helped students learn about professional roles and responsibilities, healthcare systems, and health needs of a population. It made biomedical, behavioural, and social sciences more relevant and easier to learn. It motivated and rewarded teachers and patients and enriched curriculums. In some countries,junior students provided preventive health care directly to underserved populations. Conclusion Early experience helps medical students learn, helps them develop appropriate attitudes towards their studies and future practice, and orientates medical curriculums towards society's needs. Experimental evidence of its benefit is unlikely to be forthcoming and yet more medical schools are likely to provide it. Effort could usefully be concentrated on evaluating the methods and outcomes of early experience provided within non-experimental research designs, and using that evaluation to improve the quality of curriculums.

Tracks of Change - the changing value commitments of non-profit organisations

If nonprofit organisations are moving towards more market oriented ways of operating, is this changing the traditional meanings and value of commitments associated with their activities? This article discusses the findings of a research project conducted by the University of Queensland into the impact that changes in government policies are having on the community services sector, in particular disability services. The values and belief systems traditionally associated with the sector were found to be fundamentally unaltered.