Relational and Allegorical Semantics for Constraint Logic Programming

El cálculo de relaciones binarias fue creado por De Morgan en 1860 para ser posteriormente desarrollado en gran medida por Peirce y Schröder. Tarski, Givant, Freyd y Scedrov demostraron que las álgebras relacionales son capaces de formalizar la lógica de primer orden, la lógica de orden superior así como la teoría de conjuntos. A partir de los resultados matemáticos de Tarski y Freyd, esta tesis desarrolla semánticas denotacionales y operacionales para la programación lógica con restricciones usando el álgebra relacional como base. La idea principal es la utilización del concepto de semántica ejecutable, semánticas cuya característica principal es el que la ejecución es posible utilizando el razonamiento estándar del universo semántico, este caso, razonamiento ecuacional. En el caso de este trabajo, se muestra que las álgebras relacionales distributivas con un operador de punto fijo capturan toda la teoría y metateoría estándar de la programación lógica con restricciones incluyendo los árboles utilizados en la búsqueda de demostraciones. La mayor parte de técnicas de optimización de programas, evaluación parcial e interpretación abstracta pueden ser llevadas a cabo utilizando las semánticas aquí presentadas. La demostración de la corrección de la implementación resulta extremadamente sencilla. En la primera parte de la tesis, un programa lógico con restricciones es traducido a un conjunto de términos relacionales. La interpretación estándar en la teoría de conjuntos de dichas relaciones coincide con la semántica estándar para CLP. Las consultas contra el programa traducido son llevadas a cabo mediante la reescritura de relaciones. Para concluir la primera parte, se demuestra la corrección y equivalencia operacional de esta nueva semántica, así como se define un algoritmo de unificación mediante la reescritura de relaciones. La segunda parte de la tesis desarrolla una semántica para la programación lógica con restricciones usando la teoría de alegorías—versión categórica del álgebra de relaciones—de Freyd. Para ello, se definen dos nuevos conceptos de Categoría Regular de Lawvere y _-Alegoría, en las cuales es posible interpretar un programa lógico. La ventaja fundamental que el enfoque categórico aporta es la definición de una máquina categórica que mejora e sistema de reescritura presentado en la primera parte. Gracias al uso de relaciones tabulares, la máquina modela la ejecución eficiente sin salir de un marco estrictamente formal. Utilizando la reescritura de diagramas, se define un algoritmo para el cálculo de pullbacks en Categorías Regulares de Lawvere. Los dominios de las tabulaciones aportan información sobre la utilización de memoria y variable libres, mientras que el estado compartido queda capturado por los diagramas. La especificación de la máquina induce la derivación formal de un juego de instrucciones eficiente. El marco categórico aporta otras importantes ventajas, como la posibilidad de incorporar tipos de datos algebraicos, funciones y otras extensiones a Prolog, a la vez que se conserva el carácter 100% declarativo de nuestra semántica. ABSTRACT The calculus of binary relations was introduced by De Morgan in 1860, to be greatly developed by Peirce and Schröder, as well as many others in the twentieth century. Using different formulations of relational structures, Tarski, Givant, Freyd, and Scedrov have shown how relation algebras can provide a variable-free way of formalizing first order logic, higher order logic and set theory, among other formal systems. Building on those mathematical results, we develop denotational and operational semantics for Constraint Logic Programming using relation algebra. The idea of executable semantics plays a fundamental role in this work, both as a philosophical and technical foundation. We call a semantics executable when program execution can be carried out using the regular theory and tools that define the semantic universe. Throughout this work, the use of pure algebraic reasoning is the basis of denotational and operational results, eliminating all the classical non-equational meta-theory associated to traditional semantics for Logic Programming. All algebraic reasoning, including execution, is performed in an algebraic way, to the point we could state that the denotational semantics of a CLP program is directly executable. Techniques like optimization, partial evaluation and abstract interpretation find a natural place in our algebraic models. Other properties, like correctness of the implementation or program transformation are easy to check, as they are carried out using instances of the general equational theory. In the first part of the work, we translate Constraint Logic Programs to binary relations in a modified version of the distributive relation algebras used by Tarski. Execution is carried out by a rewriting system. We prove adequacy and operational equivalence of the semantics. In the second part of the work, the relation algebraic approach is improved by using allegory theory, a categorical version of the algebra of relations developed by Freyd and Scedrov. The use of allegories lifts the semantics to typed relations, which capture the number of logical variables used by a predicate or program state in a declarative way. A logic program is interpreted in a _-allegory, which is in turn generated from a new notion of Regular Lawvere Category. As in the untyped case, program translation coincides with program interpretation. Thus, we develop a categorical machine directly from the semantics. The machine is based on relation composition, with a pullback calculation algorithm at its core. The algorithm is defined with the help of a notion of diagram rewriting. In this operational interpretation, types represent information about memory allocation and the execution mechanism is more efficient, thanks to the faithful representation of shared state by categorical projections. We finish the work by illustrating how the categorical semantics allows the incorporation into Prolog of constructs typical of Functional Programming, like abstract data types, and strict and lazy functions.

A questão da terra no livro de Jó - Um estudo exegético de Jó 15

O sofrimento que aparece no livro de Jó pode ser considerado de diversas formas. Esta dissertação analisa a questão da terra como um eixo em torno do qual Jó e seus interlocutores debatem. Não se trata de um simples debate entre sábios, mas de uma situação de violência social, vitimando principalmente os pobres. Estes, não tendo como pagar os tributos exigidos pelo sistema imperial, vêem suas terras e casas invadidas, as marcas divisórias de suas propriedades mudadas, seus animais roubados e suas vidas reduzidas à escravidão. A terra está sendo violada, a injustiça é visível e o tribunal encontra-se fechado para ouvir o clamor dos injustiçados. Contemplando toda essa realidade, Jó lança seu grito de protesto. Três amigos chegam para o consolar, mas não entram a fundo na questão levantada. Elifaz e seus companheiros têm uma posição diferente da de Jó. A dissertação está organizada em três capítulos. O primeiro apresenta uma visão geral do livro de Jó, com observações necessárias em função do estudo a ser feito, com enfoque no diálogo de Elifaz, na questão da terra na Bíblia e no período persa. O segundo capítulo é dedicado à análise exegética do capítulo 15. A divisão em três partes respeita o argumento de Elifaz: a condenação às palavras de Jó, um ensinamento em relação à terra e a condenação do ímpio. O último capítulo amplia a visão da questão da terra para todo o livro de Jó e procura identificar cada um dos personagens: os estrangeiros, os ímpios, os interlocutores de Jó, os pobres e o próprio Jó. O importante é saber qual o lugar que cada um ocupa na sociedade e o que eles representam na questão da terra. (AU)

A questão da terra no livro de Jó - Um estudo exegético de Jó 15

O sofrimento que aparece no livro de Jó pode ser considerado de diversas formas. Esta dissertação analisa a questão da terra como um eixo em torno do qual Jó e seus interlocutores debatem. Não se trata de um simples debate entre sábios, mas de uma situação de violência social, vitimando principalmente os pobres. Estes, não tendo como pagar os tributos exigidos pelo sistema imperial, vêem suas terras e casas invadidas, as marcas divisórias de suas propriedades mudadas, seus animais roubados e suas vidas reduzidas à escravidão. A terra está sendo violada, a injustiça é visível e o tribunal encontra-se fechado para ouvir o clamor dos injustiçados. Contemplando toda essa realidade, Jó lança seu grito de protesto. Três amigos chegam para o consolar, mas não entram a fundo na questão levantada. Elifaz e seus companheiros têm uma posição diferente da de Jó. A dissertação está organizada em três capítulos. O primeiro apresenta uma visão geral do livro de Jó, com observações necessárias em função do estudo a ser feito, com enfoque no diálogo de Elifaz, na questão da terra na Bíblia e no período persa. O segundo capítulo é dedicado à análise exegética do capítulo 15. A divisão em três partes respeita o argumento de Elifaz: a condenação às palavras de Jó, um ensinamento em relação à terra e a condenação do ímpio. O último capítulo amplia a visão da questão da terra para todo o livro de Jó e procura identificar cada um dos personagens: os estrangeiros, os ímpios, os interlocutores de Jó, os pobres e o próprio Jó. O importante é saber qual o lugar que cada um ocupa na sociedade e o que eles representam na questão da terra. (AU)

Jun NH2-terminal kinase is constitutively activated in T cells transformed by the intracellular parasite Theileria parva

When T cells become infected by the parasite Theileria parva, they acquire a transformed phenotype and no longer require antigen-specific stimulation or exogenous growth factors. This is accompanied by constitutive interleukin 2 (IL-2) and IL-2 receptor expression. Transformation can be reversed entirely by elimination of the parasites using the specific drug BW720c. Extracellular signal-regulated kinase and jun NH2-terminal kinase (JNK) are members of the mitogen-activated protein kinase family, which play a central role in the regulation of cellular differentiation and proliferation and also participate in the regulation of IL-2 and IL-2 receptor gene expression. T. parva was found to induce an unorthodox pattern of mitogen-activated protein kinase expression in infected T cells. JNK-1 and JNK-2 are constitutively active in a parasite-dependent manner, but have altered properties. In contrast, extracellular signal-regulated kinase-2 is not activated even though its activation pathway is functionally intact. Different components of the T cell receptor (TCR)-dependent signal transduction pathways also were examined. The TCRζ or CD3ɛ chains were found not to be phosphorylated and T. parva-transformed T cells were resistant to inhibitors that block the early steps of T cell activation. Compounds that inhibit the progression of T cells to proliferation, however, were inhibitory. Our data provide the first example, to our knowledge, for parasite-mediated JNK activation, and our findings strongly suggest that T. parva not only lifts the requirement for antigenic stimulation but also entirely bypasses early TCR-dependent signal transduction pathways to induce continuous proliferation.

Erie Canal, New York, 1821 (Raster Image) (Image 1 of 2)

This layer is a georeferenced raster image of the historic paper map entitled: A new map and profile of the proposed canal from Lake Erie to Hudson River in the state of New York, contracted by direction of the Canal Commissioners from the maps of the engineers. It was printed by W. A. Mercein in 1821. Scale [1:253,440]. This layer is image 1 of 2 total images of the two sheet source map, representing the eastern portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator (UTM) Zone 18N NAD83 projection. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, cities and towns, county boundaries, and more. Relief is shown by hachures. Includes inset profiles: A profile of the extent of the levels and of the places and lifts of the locks between Lake Erie and the Hudson -- A profile of the southern route west of the Genesee River. Includes table of distances. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Erie Canal, New York, 1821 (Raster Image) (Image 2 of 2)

This layer is a georeferenced raster image of the historic paper map entitled: A new map and profile of the proposed canal from Lake Erie to Hudson River in the state of New York, contracted by direction of the Canal Commissioners from the maps of the engineers. It was printed by W. A. Mercein in 1821. Scale [1:253,440]. This layer is image 2 of 2 total images of the two sheet source map, representing the western portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator (UTM) Zone 18N NAD83 projection. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, cities and towns, county boundaries, and more. Relief is shown by hachures. Includes inset profiles: A profile of the extent of the levels and of the places and lifts of the locks between Lake Erie and the Hudson -- A profile of the southern route west of the Genesee River. Includes table of distances. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

National Workshop on Bus-Wheelchair Accessibility, May 7-9, 1986.

"UMTA Technical Assistance Program"--Cover.

Ergonomic issues in team lifting

In this article we review and critique the current body of scientific knowledge regarding the use of team lifting including: (a) psychophysical studies of team lifting capacity, and (b) studies of manual handling, patient handling, and stretcher carriage performed by lifting teams. The consensus of the research literature is that team-lifting capacity is greater than the lifting capacity of an individual, but that the capacity of lifting teams is less than the summed capacity of individual team members. Further, biomechanical, psychophysical, and physiological stress tends to be reduced compared to the equivalent lifts and transfers performed by individuals. However, the stress associated with team lifting depends on a broad range of individual team member, load, task and environmental factors, which can interact in unexpected ways. Caution is therefore recommended against making broad assumptions regarding the use of team lifting. Future studies are needed to examine how effort and load are distributed among lifting team members, with emphasis on identifying factors that may increase the risk of injury.

A questão da terra no livro de Jó - Um estudo exegético de Jó 15

O sofrimento que aparece no livro de Jó pode ser considerado de diversas formas. Esta dissertação analisa a questão da terra como um eixo em torno do qual Jó e seus interlocutores debatem. Não se trata de um simples debate entre sábios, mas de uma situação de violência social, vitimando principalmente os pobres. Estes, não tendo como pagar os tributos exigidos pelo sistema imperial, vêem suas terras e casas invadidas, as marcas divisórias de suas propriedades mudadas, seus animais roubados e suas vidas reduzidas à escravidão. A terra está sendo violada, a injustiça é visível e o tribunal encontra-se fechado para ouvir o clamor dos injustiçados. Contemplando toda essa realidade, Jó lança seu grito de protesto. Três amigos chegam para o consolar, mas não entram a fundo na questão levantada. Elifaz e seus companheiros têm uma posição diferente da de Jó. A dissertação está organizada em três capítulos. O primeiro apresenta uma visão geral do livro de Jó, com observações necessárias em função do estudo a ser feito, com enfoque no diálogo de Elifaz, na questão da terra na Bíblia e no período persa. O segundo capítulo é dedicado à análise exegética do capítulo 15. A divisão em três partes respeita o argumento de Elifaz: a condenação às palavras de Jó, um ensinamento em relação à terra e a condenação do ímpio. O último capítulo amplia a visão da questão da terra para todo o livro de Jó e procura identificar cada um dos personagens: os estrangeiros, os ímpios, os interlocutores de Jó, os pobres e o próprio Jó. O importante é saber qual o lugar que cada um ocupa na sociedade e o que eles representam na questão da terra. (AU)

Cost models for engineering services

This thesis describes the procedure and results from four years research undertaken through the IHD (Interdisciplinary Higher Degrees) Scheme at Aston University in Birmingham, sponsored by the SERC (Science and Engineering Research Council) and Monk Dunstone Associates, Chartered Quantity Surveyors. A stochastic networking technique VERT (Venture Evaluation and Review Technique) was used to model the pre-tender costs of public health, heating ventilating, air-conditioning, fire protection, lifts and electrical installations within office developments. The model enabled the quantity surveyor to analyse, manipulate and explore complex scenarios which previously had defied ready mathematical analysis. The process involved the examination of historical material costs, labour factors and design performance data. Components and installation types were defined and formatted. Data was updated and adjusted using mechanical and electrical pre-tender cost indices and location, selection of contractor, contract sum, height and site condition factors. Ranges of cost, time and performance data were represented by probability density functions and defined by constant, uniform, normal and beta distributions. These variables and a network of the interrelationships between services components provided the framework for analysis. The VERT program, in this particular study, relied upon Monte Carlo simulation to model the uncertainties associated with pre-tender estimates of all possible installations. The computer generated output in the form of relative and cumulative frequency distributions of current element and total services costs, critical path analyses and details of statistical parameters. From this data alternative design solutions were compared, the degree of risk associated with estimates was determined, heuristics were tested and redeveloped, and cost significant items were isolated for closer examination. The resultant models successfully combined cost, time and performance factors and provided the quantity surveyor with an appreciation of the cost ranges associated with the various engineering services design options.

SENSORIMOTOR WORKING MEMORY CAPACITY LIMITS

Two novel studies examining the capacity and characteristics of working memory for object weights, experienced through lifting, were completed. Both studies employed visually identical objects of varying weight and focused on memories linking object locations and weights. Whereas numerous studies have examined the capacity of visual working memory, the capacity of sensorimotor memory involved in motor control and object manipulation has not yet been explored. In addition to assessing working memory for object weights using an explicit perceptual test, we also assessed memory for weight using an implicit measure based on motor performance. The vertical lifting or LF and the horizontal GF applied during lifts, measured from force sensors embedded in the object handles, were used to assess participants’ ability to predict object weights. In Experiment 1, participants were presented with sets of 3, 4, 5, 7 or 9 objects. They lifted each object in the set and then repeated this procedure 10 times with the objects lifted either in a fixed or random order. Sensorimotor memory was examined by assessing, as a function of object set size, how lifting forces changed across successive lifts of a given object. The results indicated that force scaling for weight improved across the repetitions of lifts, and was better for smaller set sizes when compared to the larger set sizes, with the latter effect being clearest when objects were lifting in a random order. However, in general the observed force scaling was poorly scaled. In Experiment 2, working memory was examined in two ways: by determining participants’ ability to detect a change in the weight of one of 3 to 6 objects lifted twice, and by simultaneously measuring the fingertip forces applied when lifting the objects. The results showed that, even when presented with 6 objects, participants were extremely accurate in explicitly detecting which object changed weight. In addition, force scaling for object weight, which was generally quite weak, was similar across set sizes. Thus, a capacity limit less than 6 was not found for either the explicit or implicit measures collected.

Neuartiges Modell des Querverhaltens von FFZ-Reifen

Die dynamische Standsicherheit ist beim Betrieb eines Gegengewichtsgabelstaplers eine entscheidende Größe. Diese wird neben der Position des Gesamtschwerpunktes und den geometrischen Abmaßen wesentlich von den Reifeneigenschaften bestimmt. Ein neues Rechenmodell der Super-Elastik-Reifen ermöglicht genauere Simulationen, tiefere Einblicke in das dynamische Verhalten der Fahrzeuge bei der Auslegung und somit bessere dynamische Standsicherheit.

Canadian Society for Exercise Physiology position stand : the use of instability to train the core in athletic and nonathletic conditioning

The use of instability devices and exercises to train the core musculature is an essential feature of many training centres and programs. It was the intent of this position stand to provide recommendations regarding the role of instability in resistance training programs designed to train the core musculature. The core is defined as the axial skeleton and all soft tissues with a proximal attachment originating on the axial skeleton, regardless of whether the soft tissue terminates on the axial or appendicular skeleton. Core stability can be achieved with a combination of muscle activation and intra-abdominal pressure. Abdominal bracing has been shown to be more effective than abdominal hollowing in optimizing spinal stability. When similar exercises are performed, core and limb muscle activation are reported to be higher under unstable conditions than under stable conditions. However, core muscle activation that is similar to or higher than that achieved in unstable conditions can also be achieved with ground-based free-weight exercises, such as Olympic lifts, squats, and dead lifts. Since the addition of unstable bases to resistance exercises can decrease force, power, velocity, and range of motion, they are not recommended as the primary training mode for athletic conditioning. However, the high muscle activation with the use of lower loads associated with instability resistance training suggests they can play an important role within a periodized training schedule, in rehabilitation programs, and for nonathletic individuals who prefer not to use ground-based free weights to achieve musculoskeletal health benefits.

The Documentary Take

Documentary photography and contemporary art are existentially quite distinct practices. Occasionally, with the passing of time, great documentary lifts from the contact sheet, the magazine page or the short print run book and finds its way onto gallery walls as art.Presented within the context of Walker Evans: the magazine work, curated by David Campany, The documentary take invites the question, what aspects of documentary practice are seeping into contemporary art now? In his commentary and practice, Evans distinguished between documentary as a forensic practice and the 'documentary style', which he saw as art making.With the exception of work presented by Ponch Hawkes and David Wadelton, the artists here—Destiny Deacon and Virginia Fraser; Simryn Gill; Sonia Leber and David Chesworth; Louis Porter; Patrick Pound and Charlie Sofo—are far from documentarians, yet all benefit from proximity to the foundational practice of Walker Evans.While Walker Evans may or may not be influential on these artists, his work forms a language that is now background knowledge for the making of images about the world where, artifice aside, truth is at least relevant. Perhaps documentary practice enables contemporary art to "attend to the real" [i], without binding it to a utilitarian or forensic intention.In attending to the real, the quest for the documentarian is to reveal something of the world, while that of the contemporary artist is to make meaning in and of the world.