UKC Orbix Survival Guide

Orbix is a faithfull implementation of the CORBA standard developed by Iona of Ireland. This documents is a tutorial to using Orbix to produce distibuted applications. An example program is developed one step at a time and each of the stages is explained. The appendix contains a checklist to help when developing your own applications

The Design and Implementation of the RPC Device Drivers

The RPC project group is investigating high performance communication network interface structures which are compatible with existing operating systems, in this instance SunOS 4.1 Unix. The use of parallel processing in the marshalling and unmarshalling of RPC arguments together with direct I/O to and from the user's data area and early scheduling of user processes, are expected to give a higher throughput than more traditional implementations. The network front end comprises PC based TRAM's. The Unix machine is a Sun SPARC1+ running SunOS 4.1.3. The interconnection between the two systems is by the SCSI bus. To implement this structure requires a kernel device driver to act as a bridge between the Unix environment on the SPARC station and the TRAM's in the PC. This report describes the structure and implementation of this device driver, showing the design adopted to provide multiple rpc interfaces over a single SCSI bus

No accounting for risk

At the present time, the relation between accounting praxis and risk is not well understood. Accounting praxis does not appear to regard the risk it identifies with its activities as being different from 'objective risk' - the concept of risk found in positive financial and accounting research. Instead accounting praxis (as reflected in case studies, surveys and other empirical studies) reveal a collection of different, sometimes contradictory, conceptions and 'taken for granted' understandings of risk that are invoked and applied on an ad hoc, case by case basis. The aim of this paper is to demonstrate that the conceptual disarray in accounting for risk is both costly and unnecessary. Taking an interdisciplinary approach to risk research, the authors review developments in risk thinking at the end of the 20th Century and highlight a way forward for accounting through New Paradigm Risk (NPR). Various illustrations and case study examples are drawn upon to reflect the relevance of NPR to accounting praxis

Mobilizing learning: mobile Web 2.0 scenarios in tertiary education

Based upon three years of mobile learning (mlearning) projects, a major implementation project has been developed for integrating the use of mobile web 2.0 tools across a variety of departments and courses in a tertiary education environment. A participatory action research methodology guides and informs the project. The project is based upon an explicit social constuctivist pedagogy, focusing on student collaboration, and the sharing and critique of student-generated content using freely available web 2.0 services. These include blogs, social networks, location aware (geotagged) image and video sharing, instant messaging, microblogging etc… Students and lecturers are provided with either an appropriate smartphone and/or a 3G capable netbook to use as their own for the duration of the project. Keys to the projects success are the level of pedagogical and technical support, and the level of integration of the tools into the courses – including assessment and lecturer modelling of the use of the tools. The projects are supported by an intentional community of practice model, with the researcher taking on the role of the “technology steward”. The paper outlines three different scenarios illustrating how this course integration is being achieved, establishing a transferable model of mobile web 2.0 integration and implementation. The goal is to facilitate a student-centred, collaborative, flexible, context-bridging learning environment that empowers students as content producers and learning context generators, guided by lecturers who effectively model th

The Effect of Control Strategy on Tidal Stream Turbine Performance in Laboratory and Field Experiments

The first aim of the research presented here is to examine the effect of turbine control by comparing a passive open-loop control strategy with a constant rotational speed proportional–integral–derivative (PID) feedback loop control applied to the same experimental turbine. The second aim is to evaluate the effect of unsteady inflow on turbine performance by comparing results from a towing-tank, in the absence of turbulence, with results from the identical machine in a tidal test site. The results will also inform the reader of: (i) the challenges of testing tidal turbines in unsteady tidal flow conditions in comparison to the controlled laboratory environment; (ii) calibration of acoustic Doppler flow measurement instruments; (iii) characterising the inflow to a turbine and identifying the uncertainties from unsteady inflow conditions by adaptation of the International Electrotechnical Commission technical specification (IEC TS): 62600-200. The research shows that maintaining a constant rotational speed with a control strategy yields a 13.7% higher peak power performance curve in the unsteady flow environment, in comparison to an open-loop control strategy. The research also shows an 8.0% higher peak power performance in the lab compared to the field, demonstrating the effect of unsteady flow conditions on power performance. The research highlights the importance of a tidal turbines control strategy when designing experiments

Richer concepts are better remembered: number of features effects in free recall

Many models of memory build in a term for encoding variability, the observation that there can be variability in the richness or extensiveness of processing at encoding, and that this variability has consequences for retrieval. In four experiments, we tested the expectation that encoding variability could be driven by the properties of the to-be-remembered item. Specifically, that concepts associated with more semantic features would be better remembered than concepts associated with fewer semantic features. Using feature listing norms we selected sets of items for which people tend to list higher numbers of features (high NoF) and items for which people tend to list lower numbers of features (low NoF). Results showed more accurate free recall for high NoF concepts than for low NoF concepts in expected memory tasks (Experiments 1–3) and also in an unexpected memory task (Experiment 4). This effect was not the result of associative chaining between study items (Experiment 3), and can be attributed to the amount of item-specific processing that occurs at study (Experiment 4). These results provide evidence that stimulus-specific differences in processing at encoding have consequences for explicit memory retrieval

An Abundance of Riches: Cross-Task Comparisons of Semantic Richness Effects in Visual Word Recognition

There is considerable evidence (e.g., Pexman et al., 2008) that semantically rich words, which are associated with relatively more semantic information, are recognized faster across different lexical processing tasks. The present study extends this earlier work by providing the most comprehensive evaluation to date of semantic richness effects on visual word recognition performance. Specifically, using mixed effects analyses to control for the influence of correlated lexical variables, we considered the impact of number of features, number of senses, semantic neighborhood density, imageability, and body–object interaction across five visual word recognition tasks: standard lexical decision, go/no-go lexical decision, speeded pronunciation, progressive demasking, and semantic classification. Semantic richness effects could be reliably detected in all tasks of lexical processing, indicating that semantic representations, particularly their imaginal and featural aspects, play a fundamental role in visual word recognition. However, there was also evidence that the strength of certain richness effects could be flexibly and adaptively modulated by task demands, consistent with an intriguing interplay between task-specific mechanisms and differentiated semantic processing

Spatial and temporal behavioural responses of wild cattle to tropical forest degradation

<div><p>Identifying the consequences of tropical forest degradation is essential to mitigate its effects upon forest fauna. Large forest-dwelling mammals are often highly sensitive to environmental perturbation through processes such as fragmentation, simplification of habitat structure, and abiotic changes including increased temperatures where the canopy is cleared. Whilst previous work has focused upon species richness and rarity in logged forest, few look at spatial and temporal behavioural responses to forest degradation. Using camera traps, we explored the relationships between diel activity, behavioural expression, habitat use and ambient temperature to understand how the wild free-ranging Bornean banteng (<i>Bos javanicus lowi</i>) respond to logging and regeneration. Three secondary forests in Sabah, Malaysian Borneo were studied, varying in the time since last logging (6–23 years). A combination of generalised linear mixed models and generalised linear models were constructed using >36,000 trap-nights. Temperature had no significant effect on activity, however it varied markedly between forests, with the period of intense heat shortening as forest regeneration increased over the years. Bantengs regulated activity, with a reduction during the wet season in the most degraded forest (z = -2.6, Std. Error = 0.13, p = 0.01), and reductions during midday hours in forest with limited regeneration, however after >20 years of regrowth, activity was more consistent throughout the day. Foraging and use of open canopy areas dominated the activity budget when regeneration was limited. As regeneration advanced, this was replaced by greater investment in travelling and using a closed canopy. Forest degradation modifies the ambient temperature, and positively influences flooding and habitat availability during the wet season. Retention of a mosaic of mature forest patches within commercial forests could minimise these effects and also provide refuge, which is key to heat dissipation and the prevention of thermal stress, whilst retention of degraded forest could provide forage.</p></div

Aqueous Humor Stimulates the Migration of Human Trabecular Meshwork Cells In Vitro

PURPOSE. Depletion of trabecular meshwork cell numbers is a feature of the outflow system in aging and in primary open-angle glaucoma. It is possible that migration stimulated by factors present in aqueous humor may contribute to the cell loss. This investigation assessed the chemoattractant potential of glaucomatous and nonglaucomatous human aqueous humor and fibronectin, one of its constituents, on a range of cultured trabecular meshwork cell lines. METHODS. Migration was assessed in 48-well modified Boyden chambers. The potential migratory stimulants were soluble fibronectin and glaucomatous and nonglaucomatous aqueous humor. The glaucomatous aqueous samples were collected from patients undergoing trabeculotomy for primary open-angle glaucoma and the normal aqueous from normal bovine eyes and patients undergoing cataract surgery. The target cell types were normal human and bovine meshwork cells grown from explants and two human transformed meshwork cell lines from a normal (HTM-5) and a glaucomatous (HTM-3) source