942 research outputs found

    Run-time implementation issues for real-time embedded Ada

    Get PDF
    A motivating factor in the development of Ada as the department of defense standard language was the high cost of embedded system software development. It was with embedded system requirements in mind that many of the features of the language were incorporated. Yet it is the designers of embedded systems that seem to comprise the majority of the Ada community dissatisfied with the language. There are a variety of reasons for this dissatisfaction, but many seem to be related in some way to the Ada run-time support system. Some of the areas in which the inconsistencies were found to have the greatest impact on performance from the standpoint of real-time systems are presented. In particular, a large part of the duties of the tasking supervisor are subject to the design decisions of the implementer. These include scheduling, rendezvous, delay processing, and task activation and termination. Some of the more general issues presented include time and space efficiencies, generic expansions, memory management, pragmas, and tracing features. As validated compilers become available for bare computer targets, it is important for a designer to be aware that, at least for many real-time issues, all validated Ada compilers are not created equal

    Impact analysis of database schema changes

    Get PDF
    When database schemas require change, it is typical to predict the effects of the change, first to gauge if the change is worth the expense, and second, to determine what must be reconciled once the change has taken place. Current techniques to predict the effects of schema changes upon applications that use the database can be expensive and error-prone, making the change process expensive and difficult. Our thesis is that an automated approach for predicting these effects, known as an impact analysis, can create a more informed schema change process, allowing stakeholders to obtain beneficial information, at lower costs than currently used industrial practice. This is an interesting research problem because modern data-access practices make it difficult to create an automated analysis that can identify the dependencies between applications and the database schema. In this dissertation we describe a novel analysis that overcomes these difficulties. We present a novel analysis for extracting potential database queries from a program, called query analysis. This query analysis builds upon related work, satisfying the additional requirements that we identify for impact analysis. The impacts of a schema change can be predicted by analysing the results of query analysis, using a process we call impact calculation. We describe impact calculation in detail, and show how it can be practically and efficiently implemented. Due to the level of accuracy required by our query analysis, the analysis can become expensive, so we describe existing and novel approaches for maintaining an efficient and computational tractable analysis. We describe a practical and efficient prototype implementation of our schema change impact analysis, called SUITE. We describe how SUITE was used to evaluate our thesis, using a historical case study of a large commercial software project. The results of this case study show that our impact analysis is feasible for large commercial software applications, and likely to be useful in real-world software development

    Ambiguity seeking as a result of the status quo bias

    Get PDF
    Several factors affect attitudes toward ambiguity. What happens, however, when people are asked to exchange an ambiguous alternative in their possession for an unambiguous one? We present three experiments in which individuals preferred to retain the former. This status quo bias emerged both within- and between-subjects, with and without incentives, with different outcome distributions, and with endowments determined by both the experimenter and the participants themselves. Findings emphasize the need to account for the frames of reference under which evaluations of probabilistic information take place as well as modifications that should be incorporated into descriptive models of decision making.Ambiguity, risk, status quo bias, decision making, uncertainty, Leex

    Custo de produção do gado puro sangue CharolĂȘs.

    Get PDF
    Foi estimado o custo da criação do rebanho CharolĂȘs, mantido para fim de pesquisa na UEPAE de SĂŁo Carlos, com o objetivo de colher subsidios para o estudo da economicidade da pesquisa e de registrar incidĂȘncias de custo aplicĂĄveis a criação a nĂ­vel de empresa

    <i>Schistosoma mansoni</i> cercariae experience influx of macromolecules during skin penetration

    Get PDF
    We have observed that when cercariae penetrate the skin of mice, there is influx into their tissues of Lucifer Yellow and certain labelled molecules of up to 20 kDa molecular weight. This observation was made using a variety of fluorescent membrane-impermeant compounds injected into the skin before the application of cercariae. This unexpected phenomenon was investigated further by transforming cercariae in vitro in the presence of the membrane-impermeant compounds and examining the distribution by microscopy. In schistosomula derived from this procedure, the nephridiopore and surface membrane were labelled while the pre- and post-acetabular glands were not labelled. The region associated with the oesophagus within the pharyngeal muscle clearly contained the fluorescent molecules, as did the region adjacent to the excretory tubules and the germinal mass. We used cercariae stained with carmine to aid identification of regions labelled with Lucifer Yellow. Although the mechanism of this influx is unclear, the observation is significant. From it, we can suggest an hypothesis that, during skin penetration, exposure of internal tissues of the parasite to external macromolecules represents a novel host-parasite interfac

    Aiding Lay Decision Making Using a Cognitive Competencies Approach

    Get PDF
    Two prescriptive approaches have evolved to aid human decision making: just in time interventions that provide support as a decision is being made; and just in case interventions that educate people about future events that they may encounter so that they are better prepared to make an informed decision when these events occur. We review research on these two approaches developed in the context of supporting everyday decisions such as choosing an apartment, a financial product or a medical procedure. We argue that the lack of an underlying prescriptive theory has limited the development and evaluation of these interventions. We draw on recent descriptive research on the cognitive competencies that underpin human decision making to suggest new ways of interpreting how and why existing decision aids may be effective and suggest a different way of evaluating their effectiveness. We also briefly outline how our approach has the potential to develop new interventions to support everyday decision making and highlight the benefits of drawing on descriptive research when developing and evaluating interventions

    Callose deposition and symplastic connectivity are regulated prior to lateral root emergence.

    Get PDF
    Root growth is critical for the effective exploitation of the rhizosphere and productive plant growth. Our recent work(1) showed that root architecture was dependent upon the degree of symplastic connectivity between neighboring cells during the specification of lateral root primordia and was affected by genes regulating callose deposition at plasmodesmata (PD). Here we provide additional evidence that both symplastic connectivity and callose are also important during the later phase of lateral root development: emergence. Callose immunolocalization assays indicated that transient symplastic isolation of the primordium occur immediately prior to emergence through the overlaying tissues to produce the mature lateral root.(1) Here we could corroborate these results by analyzing the mobility of a symplastic tracer and the expression of PD genes in lateral roots and in response to auxins. Moreover, we show that altering callose deposition affects the number of emerged lateral roots suggesting that PD regulation is important for emergence

    The Impact of Police Misconduct in Kings County on New York City\u27s Civil Liability 2006-2010

    Full text link
    The confluence of police misconduct and civil liability is an issue of growing concern for many communities throughout the U.S. today. The gravamen of the issue is evident in increases in the number of lawsuits alleging police misconduct and the civil liability that results from these lawsuits. In New York City during the period 1997-2005 the cost for police misconduct went from 27.9millionin1997to27.9 million in 1997 to 40.4 million in 2005 (Thompson, 2007). Concerns over these increases have resulted in efforts to curb both the number of lawsuits brought against the New York Police Department and the civil liability to the City that results from these lawsuits. The study examines and describes the impact of allegations of police misconduct in Kings County during the years 2006-2010 on New York City\u27s civil liability. Using allegations of police misconduct in lawsuits that resulted in a settlement or jury award as a measure of police misconduct, the study provides evidence of the increasing costs of police misconduct in Kings County, New York. The study found that the increasing financial impact that police misconduct had on the City during the years studied was not the result of the increasing costs of settlements and jury awards per se but rather the increase in the number of lawsuits vis-Ă  -vis the increase in the incidence of police misconduct
    • 

    corecore