Modeling a mobile robot using a grammatical model

Virtual Worlds Generator is a grammatical model that is proposed to define virtual worlds. It integrates the diversity of sensors and interaction devices, multimodality and a virtual simulation system. Its grammar allows the definition and abstraction in symbols strings of the scenes of the virtual world, independently of the hardware that is used to represent the world or to interact with it. A case study is presented to explain how to use the proposed model to formalize a robot navigation system with multimodal perception and a hybrid control scheme of the robot.

A grammatical approach to the modeling of an autonomous robot

Virtual Worlds Generator is a grammatical model that is proposed to define virtual worlds. It integrates the diversity of sensors and interaction devices, multimodality and a virtual simulation system. Its grammar allows the definition and abstraction in symbols strings of the scenes of the virtual world, independently of the hardware that is used to represent the world or to interact with it. A case study is presented to explain how to use the proposed model to formalize a robot navigation system with multimodal perception and a hybrid control scheme of the robot. The result is an instance of the model grammar that implements the robotic system and is independent of the sensing devices used for perception and interaction. As a conclusion the Virtual Worlds Generator adds value in the simulation of virtual worlds since the definition can be done formally and independently of the peculiarities of the supporting devices.

Construction of Intelligent Virtual Worlds Using a Grammatical Framework

The potential of integrating multiagent systems and virtual environments has not been exploited to its whole extent. This paper proposes a model based on grammars, called Minerva, to construct complex virtual environments that integrate the features of agents. A virtual world is described as a set of dynamic and static elements. The static part is represented by a sequence of primitives and transformations and the dynamic elements by a series of agents. Agent activation and communication is achieved using events, created by the so-called event generators. The grammar defines a descriptive language with a simple syntax and a semantics, defined by functions. The semantics functions allow the scene to be displayed in a graphics device, and the description of the activities of the agents, including artificial intelligence algorithms and reactions to physical phenomena. To illustrate the use of Minerva, a practical example is presented: a simple robot simulator that considers the basic features of a typical robot. The result is a functional simple simulator. Minerva is a reusable, integral, and generic system, which can be easily scaled, adapted, and improved. The description of the virtual scene is independent from its representation and the elements that it interacts with.

Ptycholepis marshi Newberry : a chondrostean fish from the Newark group of Eastern North America / Bobb Schaeffer --, David H. Dunkle --, Nicholas G. McDonald --.

v.33:no.12(1975)

Inventaire des lettres et papiers manuscrits de Gaspare, Carlo et Lodovico Vigarani conservés aux Archives d'Etat de Modène, 1634-1684 /

Errata slip inserted.

Parties and politics : an institutional and behavioral approach /

Includes bibliographical references and index.

Administrative regulation, a study in representation of interests,

Mode of access: Internet.

Structure of rare-earth phosphate glasses by neutron diffraction

Neutron diffraction was used to measure the structure of the phosphate glasses RAl0.30P3.05O9.62, where R denotes Dy or Ho, and RAl0.34P3.20O10.04, where R denotes La or Ce. For each glass, isomorphic structures were assumed and difference function methods were employed to separate, essentially, those correlations involving the rare-earth ion, R3+, from the remainder. The ratio of bridging oxygen, OB, to terminal oxygen, OT, atoms in the PO4 tetrahedra was quantified and in both materials R3+ and Al3+ are found to act as network modifying cations which bind to the OT. The R–OT coordination number is 6.7(1) and 7.5(2) for the Dy/Ho and La/Ce glasses respectively.

Juniperus navicularis - a study of Portuguese population structure and fitness

Juniperus navicularis Gand. is a dioecious endemic conifer that constitutes the understory of seaside pine forests in Portugal, areas currently threatened by increasing urban expansion. The aim of this study is to assess the conservation status of previously known populations of this species located on its core area of distribution. The study was performed in south-west coast of Portugal. Three populations varying in size and pine density were analyzed. Number of individuals, population density, spatial distribution and individual characteristics of junipers were estimated. Female cone, seed characteristics and seed viability were also evaluated. Results suggest that J. navicularis populations are vulnerable because seminal recruitment is scarce, what may lead to a reduction of genetic variability due solely to vegetative propagation. This vulnerability seems to be strongly determined by climatic constraints toward increasing aridity. Ratio between male and female shrubs did not differ from 1:1 in any population. Deviations from 1:1 between mature and non-mature plants were found in all populations, denoting population ageing. Very low seed viability was observed. A major part of described Juniperus navicularis populations have disappeared through direct habitat loss to urban development, loss of fitness in drier and warmer locations and low seed viability. This study is the first to address J. navicularis conservation, and represents a valuable first step toward this species preservation. 

New contributions to the native and alien flora in riparian habitats of the Cantabrian watershed (Northern Spain)

As a result of a floristic survey carried out in riparian habitats of northern Spain, new chorological data are provided for 9 alien and 6 native plant species. Some species are reported for the first time at regional scale, such as Carex strigosa, Helianthus x laetiflorus and Persicaria pensylvanica in Cantabria. Also noteworthy is the finding of naturalised populations of the North American grass Muhlenbergia schreberi at the Urumea river basin, which represents the second reference for the Iberian Peninsula.

Análisis y reformulación de la organización del conocimiento en las Ciencias de la Comunicación: aplicación para la codificación UNESCO

Se estudia la codificación y organización del campo de las Ciencias de la Comunicación, fundamentalmente los códigos Unesco. El objetivo es plantear un cambio en estos códigos, puesto que la forma de clasificar y organizar un dominio científico tiene consecuencias de naturaleza operativa y epistemológica en el propio trabajo científico. En este trabajo se estudia la clasificación actual, que muestra una presencia escasa y dispersa de los términos vinculados a Comunicación. Se describen las dificultades prácticas y teóricas que conlleva su reorganización, las posibles fuentes (planes de estudio, congresos, revistas científicas, propuestas documentales y palabras clave) y los métodos de trabajo que se pueden emplear, tomando como bases teóricas el dominio de la Organización del Conocimiento y el de la Comunicación. Por último, se analizan dos ámbitos disciplinares diferentes (Historia de la Comunicación y Tecnologías de la Comunicación), mediante la información recogida, en una base de datos, de asignaturas en grado y en másteres oficiales de 12 universidades españolas. También se observa que este tipo de propuesta requiere el conocimiento derivado de instrumentos documentales como las clasificaciones y los tesauros.

Metáforas del amor en la poesía de la Grecia antigua (I): la épica y la lírica arcaicas

Partiendo del concepto de metáfora cognitiva, que complementa al más conocido de metáfora literaria, y analizando la base conceptual que a ambas subyace, pretendemos un cuidadoso análisis de los textos de poesía épica y lírica arcaicas, sin olvidar la importancia fundamental del contexto cultural en que estos surgen, para obtener una mejor comprensión de la forma en que los griegos conceptualizaban el sentimiento amoroso.

The Plutarch’s Motive of "Descensus Animae" in "Nag Hammadi and the Corpus Hermeticum"

Al evaluar los contactos de Plutarco con otras culturas contemporáneas, los investigadores todavía no han llegado a un consenso acerca de la relación entre el queronense y la literatura cristiano-primitiva. Un buen ejemplo de esto aparece al atender al motivo de la creación del alma humana. La intención de las próximas páginas es, tras un análisis de los textos plutarqueos, atender a estos posibles contactos con NHC, los heresiólogos y el Corpus Hermeticum a fin de dilucidar sus similitudes y diferencias.

En busca del tiempo homérico con la mirada y la palabra de Antonio Prieto (lectura de "El ciego de Quíos")

En El ciego de Quíos, el novelista Antonio Prieto inventa la vida de Homero alimentándola con figuras y hechos procedentes de la Ilíada y, sobre todo, de la Odisea. El relato se enriquece con el conocimiento histórico en torno a los dos grandes poemas, y lo enmarca un amplio despliegue mitológico. Más allá, la novela alcanza un significado trascendente. Descubrimos como motor narrativo el esfuerzo homérico por vencer la fugacidad humana mediante la escritura, lo que crea un vínculo atemporal con el propio anhelo de nuestro autor; así, la novela nos ofrece un ejemplo máximo del fenómeno bautizado como fusión mítica por Antonio Prieto.