T on the Cray X/MP

This research was aimed at porting the T programming language, a dialect of LISP, to the Cray X/MP computer. The effort involved research into systems engineering and software engineering problems related not only to compiler design and implementation, but also to parallel computation, the X/MP being a shared-memory multiprocessor. Porting also involved the sub-tasks of retargeting the assembler, code-generator, and run-time system. A reasonably effective porting methodology that is relatively straight forward, although more difficult than table-driven approaches, has been developed. The run-time system was not ported, and thus the T programs cannot be run without explicit linking of the required run-time support. The run-time performance gain achieved in generated code was found to be disappointing. Recommendations for the achievement of higher performance are given

Warm air leads to hazardous ground temperatures when walking dogs in built and natural environments

Two case studies in Texas, one in a built environment and another in a natural se8ing, illustrate potential ground heat hazards when walking dogs on warm days. In the first case, temperatures of four different ground surfaces—concrete, grass, chip seal, and tar—were measured along a street in a suburban neighborhood. The study involved two morning and two a6ernoon surveys of 30 sampling locations where all four materials were present. Air temperatures, typical of the study area in summer, ranged from 78.0 oF (25.6 oC) in the morning to 96.1 oF (35.6 oC) in the a6ernoon. Ground surfaces reached much higher temperatures, exceeding 150 oF (65.6 oC), in the a6ernoon surveys. Median temperatures were highest in tar, followed by chip seal, concrete, and grass. The second case involved shallow lake water and various types of mud, sand, cobbles, rock fragments, and grass along a nature trail. Air temperatures ranged from 74.7 oF (23.7 oC) at 8:00 a.m. to 92.5 oF (33.6 oC) at 6:00 p.m. Ground temperatures varied considerably with material and time of day, ranging from 76.4 oF (24.7 oC) at gray cobbles and beige rock at 8:00 a.m. to 125.7 oF (52.1 oC) at brown sand at 4:00 p.m. Over the day, temperatures were highest at brown sand and lowest in water and moist sand

Nitrate and Chloride Concentrations in Groundwater beneath a Portion of the Trinity Group Outcrop Zone, Texas

This article discusses a study in which the authors evaluated spatial distributions of nitrate and chloride concentrations in groundwater in an area of north-central Texas with agricultural activity, in addition to oil and natural gas exploration and activity

Nitrate, Arsenic and Selenium Concentrations in The Pecos Valley Aquifer, West Texas, USA

This article discusses nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer in west Texas in the context of local geology and land use

Programmer avec des tuiles musicales: le T-calcul en Euterpea

International audienceEuterpea est un langage de programmation dédié à la création et à la manipulation de contenus media temporisés - son, musique, animations, vidéo, etc... Il est enchassé dans un langage de programmation fonctionnelle avec typage polymorphe: Haskell. Il hérite ainsi de toute la souplesse et la robustesse d'un langage de programmation moderne. Le T-calcul est une proposition abstraite de modélisation temporelle qui, à travers une seule opération de composition: le produit tuilé, permet tout à la fois la composition séquentielle et la composition parallèle de contenus temporisés. En présentant ici une intégration du T-calcul dans le language Euterpea, nous réalisons un outil qui devrait permettre d'évaluer la puissance métaphorique du tuilage temporel combinée avec la puissance programmatique du langage Euterpea

From out-of-time design to in-time production of temporal media

The design a temporal media, a sequence of temporal media values such as notes, sounds, images, etc., is an out-of-time task. Fairly general out-of-time program constructs are available for such a purpose. For example , when writing a musical piece, a composer can traverse back and forth his creation. On the contrary, rendering a temporal media is an in-time task. The production of notes in a musical performance is bound to be coherent with the unceasing onward flow of time. It follows that some of the out-of-time programming constructs used for the creation of that pieces must have been reordered in order to produce the right media events in the right order and at the right time. In this paper, we propose a formal study of the interplay between these in-time and these out-of-time programing constructs. With an explicitly out-of-time design approach, we eventually show that simpler and more abstract declarative programming features become available, leaving to computers the tedious task of synchronizing and scheduling the media events to be produced in-time, upon demand

Tiled Polymorphic Temporal Media

International audienceTiled Polymorphic Temporal Media (Tiled PTM) is an algebraic approach to specifying the composition of multimedia values having an inherent temporal quality --- for example sound clips, musical scores, computer animations, and video clips. Mathematically, one can think of a tiled PTM as a tiling in the one dimension of time. A tiled PTM value has two synchronization marks that specify, via an effective notion of tiled product, how the tiled PTMs are positioned in time relative to one another, possibly with overlaps. Together with a pseudo inverse operation, and the related reset and co-reset projection operators, the tiled product is shown to encompass both sequential and parallel products over temporal media. Up to observational equivalence, the resulting algebra of tiled PTM is shown to be an inverse monoid: the pseudo inverse being a semigroup inverse. These and other algebraic properties are explored in detail. In addition, recursively-defined infinite tiles are considered. Ultimately, in order for a tiled PTM to be \emph{renderable}, we must know its beginning, and how to compute its evolving value over time. Though undecidable in the general case, we define decidable special cases that still permit infinite tilings. Finally, we describe an elegant specification, implementation, and proof of key properties in Haskell, whose lazy evaluation is crucial for assuring the soundness of recursive tiles. Illustrative examples, within the Euterpea framework for musical temporal media, are provided throughout

Spatial Distribution of Solutes in Aquifer Outcrop Zones along the Brazos River, East-Central Texas

Article discussing the spatial distribution of solutes in aquifer outcrop zones along the Brazos River, East-Central Texas