Run-time implementation issues for real-time embedded Ada

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

On counting permutations by pairs of congruence classes of major index

For a fixed positive integer n, let S_n denote the symmetric group of n! permutations on n symbols, and let maj(sigma) denote the major index of a permutation sigma. For positive integers k<m not greater than n and non-negative integers i and j, we give enumerative formulas for the cardinality of the set of permutations sigma in S_n with maj(sigma) congruent to i mod k and maj(sigma^(-1)) congruent to j mod m. When m divides n-1 and k divides n, we show that for all i,j, this cardinality equals (n!)/(km).Comment: 8 page

On 'Analytical models for the patchy spread of plant disease'.

Epidemiologists are interested in using models that incorporate the effects of clustering in the spatial pattern of disease on epidemic dynamics. Bolker (1999, Bull. Math. Biol. 61, 849-874) has developed an approach to study such models based on a moment closure assumption. We show that the assumption works above a threshold initial level of disease that depends on the spatial dispersal of the pathogen. We test an alternative assumption and show that it does not have this limitation. We examine the relation between lattice and continuous-medium implementations of the approach

If only it were true: the problem with the four conditionals

The traditional division of conditionals into four main types (zero, first, second, and third) has long been called into question. Unfortunately, the awareness that this description does not reflect conditional patterns in actual usage has not generally been reflected in EFL coursebooks. This article re-examines the arguments for a description of conditional patterns which reflects actual usage and uses corpus data to demonstrate the kind of patterns in frequent use. It then suggests two teaching approaches that may help teachers to tackle a variety of conditional patterns in the classroom

Une histoire sans noms : les femmes et le concept d’auteur dans le cinéma des premiers temps

Depuis longtemps au coeur des études cinématographiques, le concept d’auteur reste encore largement inexploré dans les études portant sur le cinéma des débuts. Ce décalage s’explique par le fait que, dans le cinéma des premiers temps, le rapport établi entre sujet et pratique filmique était différent, parce qu’étranger aux stratégies d’énonciation et de réception qu’on trouvera plus tard dans le cinéma « institutionnel ». La plupart des travaux publiés sur ce sujet analysent des figures auctoriales empruntées aux arts « majeurs ». Cependant, le cinéma des premiers temps invite à situer l’auteur dans des contextes culturels différents, et ce projet est primordial pour les féministes étudiant le rôle des femmes dans le cinéma des premiers temps.While it has long been at the centre of film discourse, the concept of authorship is still largely unexplored in studies concentrating on early cinema. This lag finds explanation in the fact that early cinema presumes a different relation between subject and film practice, outside of the strategies of enunciation and reception that have been consolidated by “institutional” cinema. The majority of the work published on the subject of authorship proposes authorial models that borrow from the traditions of the “major” arts. However, early cinema invites us to reconsider the genealogy of authorship within different cultural contexts. This project is particularly important for feminists studying the role of women in early cinema

A spatial analysis of physiological changes associated with infection of cotyledons of marrow plants with cucumber mosaic virus

Changes in host primary metabolism associated with the compatible interaction between cucumber mosaic virus and cotyledons of the marrow plant (Cucurbita pepo L.) have been localized, first by measuring activities of key enzymes in infected and uninfected regions of the cotyledon, and second by histochemical techniques applied to tissue prints of the infected region. A series of progressive metabolic changes occurs within the expanding infected lesion. Virus replication and the synthesis of viral protein at the periphery creates a strong sink demand associated with increased activities of anaplerotic enzymes, increased photosynthesis, and starch accumulation. Inside the lesion, when the synthesis of virus has declined, photosynthesis is reduced, starch is mobilized, and the emphasis of metabolism is shifted toward glycolysis and mitochondrial respiration. These changes are associated spatially with the onset of chlorosis. A decrease in total protein synthesis in this inner zone could be instrumental in some or all of these changes, leading to symptoms of viral infection

Ambiguity seeking as a result of the status quo bias

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

Acquisition Data Analytics for Supply Chain Cybersecurity

Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsCybersecurity is a national priority, but the analysis required for acquisition personnel to objectively assess the integrity of the supply chain for cyber compromise is highly complex. This paper presents a process for supply chain data analytics for acquisition decision makers, addressing data collection, assessment, and reporting. The method includes workflows from initial purchase request through vendor selection and maintenance to audits across the lifecycle of an asset. Artificial intelligence can help acquisition decision makers automate the complexity of supply chain information assurance.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited