978 resultados para Shortest path problem
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Se presenta experiencia educativa que propone la creaci??n de un grupo de trabajo para analizar la problem??tica de la formaci??n profesional y proponer mejoras. Se realiza en el IES Padre P??veda en Guadix, Granada. Los objetivos son: seguimiento del cat??logo nacional de las cualificaciones profesionales y de los nuevos t??tulos de formaci??n profesional que afecta directamente a nuestro alumnado; estudiar la necesidad de implantar nuevos ciclos formativos en nuestra comunidad relacionados con la demanda de alumnado; estudiar el equilibrio o desequilibrio entre los distintos subsistemas de formaci??n profesional, e intentar evitar un estancamiento en la formaci??n profesional espec??fica; impulsar el establecimiento de los centros integrados en Andaluc??a; estudiar y analizar la legislaci??n vigente, difundi??ndola a toda nuestra comunidad escolar; analizar el plan Andaluz de formaci??n profesional; elaborar informes donde se reflejen los resultados de nuestro trabajo y darle la mayor difusi??n posible.
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A distributed method for mobile robot navigation, spatial learning, and path planning is presented. It is implemented on a sonar-based physical robot, Toto, consisting of three competence layers: 1) Low-level navigation: a collection of reflex-like rules resulting in emergent boundary-tracing. 2) Landmark detection: dynamically extracts landmarks from the robot's motion. 3) Map learning: constructs a distributed map of landmarks. The parallel implementation allows for localization in constant time. Spreading of activation computes both topological and physical shortest paths in linear time. The main issues addressed are: distributed, procedural, and qualitative representation and computation, emergent behaviors, dynamic landmarks, minimized communication.
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This paper considers the problem of language change. Linguists must explain not only how languages are learned but also how and why they have evolved along certain trajectories and not others. While the language learning problem has focused on the behavior of individuals and how they acquire a particular grammar from a class of grammars ${cal G}$, here we consider a population of such learners and investigate the emergent, global population characteristics of linguistic communities over several generations. We argue that language change follows logically from specific assumptions about grammatical theories and learning paradigms. In particular, we are able to transform parameterized theories and memoryless acquisition algorithms into grammatical dynamical systems, whose evolution depicts a population's evolving linguistic composition. We investigate the linguistic and computational consequences of this model, showing that the formalization allows one to ask questions about diachronic that one otherwise could not ask, such as the effect of varying initial conditions on the resulting diachronic trajectories. From a more programmatic perspective, we give an example of how the dynamical system model for language change can serve as a way to distinguish among alternative grammatical theories, introducing a formal diachronic adequacy criterion for linguistic theories.
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This report outlines the problem of intelligent failure recovery in a problem-solver for electrical design. We want our problem solver to learn as much as it can from its mistakes. Thus we cast the engineering design process on terms of Problem Solving by Debugging Almost-Right Plans, a paradigm for automatic problem solving based on the belief that creation and removal of "bugs" is an unavoidable part of the process of solving a complex problem. The process of localization and removal of bugs called for by the PSBDARP theory requires an approach to engineering analysis in which every result has a justification which describes the exact set of assumptions it depends upon. We have developed a program based on Analysis by Propagation of Constraints which can explain the basis of its deductions. In addition to being useful to a PSBDARP designer, these justifications are used in Dependency-Directed Backtracking to limit the combinatorial search in the analysis routines. Although the research we will describe is explicitly about electrical circuits, we believe that similar principles and methods are employed by other kinds of engineers, including computer programmers.
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Testing constraints for real-time systems are usually verified through the satisfiability of propositional formulae. In this paper, we propose an alternative where the verification of timing constraints can be done by counting the number of truth assignments instead of boolean satisfiability. This number can also tell us how “far away” is a given specification from satisfying its safety assertion. Furthermore, specifications and safety assertions are often modified in an incremental fashion, where problematic bugs are fixed one at a time. To support this development, we propose an incremental algorithm for counting satisfiability. Our proposed incremental algorithm is optimal as no unnecessary nodes are created during each counting. This works for the class of path RTL. To illustrate this application, we show how incremental satisfiability counting can be applied to a well-known rail-road crossing example, particularly when its specification is still being refined.
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The statistical analysis of literary style is the part of stylometry that compares measurable characteristics in a text that are rarely controlled by the author, with those in other texts. When the goal is to settle authorship questions, these characteristics should relate to the author’s style and not to the genre, epoch or editor, and they should be such that their variation between authors is larger than the variation within comparable texts from the same author. For an overview of the literature on stylometry and some of the techniques involved, see for example Mosteller and Wallace (1964, 82), Herdan (1964), Morton (1978), Holmes (1985), Oakes (1998) or Lebart, Salem and Berry (1998). Tirant lo Blanc, a chivalry book, is the main work in catalan literature and it was hailed to be “the best book of its kind in the world” by Cervantes in Don Quixote. Considered by writters like Vargas Llosa or Damaso Alonso to be the first modern novel in Europe, it has been translated several times into Spanish, Italian and French, with modern English translations by Rosenthal (1996) and La Fontaine (1993). The main body of this book was written between 1460 and 1465, but it was not printed until 1490. There is an intense and long lasting debate around its authorship sprouting from its first edition, where its introduction states that the whole book is the work of Martorell (1413?-1468), while at the end it is stated that the last one fourth of the book is by Galba (?-1490), after the death of Martorell. Some of the authors that support the theory of single authorship are Riquer (1990), Chiner (1993) and Badia (1993), while some of those supporting the double authorship are Riquer (1947), Coromines (1956) and Ferrando (1995). For an overview of this debate, see Riquer (1990). Neither of the two candidate authors left any text comparable to the one under study, and therefore discriminant analysis can not be used to help classify chapters by author. By using sample texts encompassing about ten percent of the book, and looking at word length and at the use of 44 conjunctions, prepositions and articles, Ginebra and Cabos (1998) detect heterogeneities that might indicate the existence of two authors. By analyzing the diversity of the vocabulary, Riba and Ginebra (2000) estimates that stylistic boundary to be near chapter 383. Following the lead of the extensive literature, this paper looks into word length, the use of the most frequent words and into the use of vowels in each chapter of the book. Given that the features selected are categorical, that leads to three contingency tables of ordered rows and therefore to three sequences of multinomial observations. Section 2 explores these sequences graphically, observing a clear shift in their distribution. Section 3 describes the problem of the estimation of a suden change-point in those sequences, in the following sections we propose various ways to estimate change-points in multinomial sequences; the method in section 4 involves fitting models for polytomous data, the one in Section 5 fits gamma models onto the sequence of Chi-square distances between each row profiles and the average profile, the one in Section 6 fits models onto the sequence of values taken by the first component of the correspondence analysis as well as onto sequences of other summary measures like the average word length. In Section 7 we fit models onto the marginal binomial sequences to identify the features that distinguish the chapters before and after that boundary. Most methods rely heavily on the use of generalized linear models
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The application of Discriminant function analysis (DFA) is not a new idea in the study of tephrochrology. In this paper, DFA is applied to compositional datasets of two different types of tephras from Mountain Ruapehu in New Zealand and Mountain Rainier in USA. The canonical variables from the analysis are further investigated with a statistical methodology of change-point problems in order to gain a better understanding of the change in compositional pattern over time. Finally, a special case of segmented regression has been proposed to model both the time of change and the change in pattern. This model can be used to estimate the age for the unknown tephras using Bayesian statistical calibration
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Determinar el alcance de los objetivos y la naturaleza de las concepciones que tienen los-as estudiantes y los materiales did??cticos, sobre la tem??tica de la energ??a, se formula los siguientes problemas: 1. ??Cu??les son las concepciones de los-las estudiantes de Magisterio sobre los modelos de Educaci??n Ambiental? 2. ??Cu??les son las concepciones de los-las estudiantes sobre los problemas socioambientales que consideran m??s importantes y la idea de riesgo asociada a los mismos? 3. ??Cu??les son las concepciones de los-las estudiantes sobre el papel que juega la participaci??n en el proceso de Educaci??n Ambiental? 4. ??Cu??les son las concepciones de los-las estudiantes sobre la energ??a y el papel que juega la energ??a como problema socioambiental? 5. ??Cu??les son las concepciones did??cticas dominantes de los-las estudiantes sobre el tratamiento did??ctico de la energ??a? 6. ??Cu??les son las concepciones did??cticas dominantes de los materiales seleccionados sobre el tratamiento de la energ??a? 7. ??Existe alguna correspondencia entre las concepciones de los-las estudiantes y las concepciones did??cticas de los materiales seleccionados sobre el tratamiento did??ctico de la energ??a? 8. ??Existen diferencias en las concepciones de los-las estudiantes sobre algunos aspectos de la Educaci??n Ambiental y de la energ??a dependiendo del momento de la investigaci??n? 9. ??Existe coherencia en las concepciones de los-las estudiantes y de los materiales?. El paradigma metodol??gico elegido se ubica en la definici??n del paradigma interpretativo, denominado tambi??n naturalista, de enfoque ecol??gico o etnogr??fico, a trav??s de un estudio de caso. Se selecciona un grupo de estudiantes de la Facultad de Ciencias de la Educaci??n de la Universidad de Sevilla, de las modalidades de Educaci??n Primaria y Especial, que cursan la asignatura optativa de Educaci??n Ambiental (EA). La muestra se compone de 12 hombres y 38 mujeres, sumando un total de 50 personas, solo se tiene materiales escritos de forma individual de 45 personas, se agrupan para trabajar de forma conjunta formando 12 grupos. Dentro del planteamiento metodol??gico adoptado, se utiliza diferentes t??cnicas e instrumentos: la b??squeda y an??lisis de materiales de EA desde un punto de vista did??ctico. Observaci??n externa y recogida de informaci??n en el diario de clase. Cuestionarios y documentos de trabajo. Grabaciones de algunas sesiones de clase. Grupo de discusi??n. Para el tratamiento de los datos se dise??a un sistema de categor??as que sistematizara las respuestas. Las respuestas m??s encontradas, sobre el modelo de EA y el car??cter interdisciplinar, se encuentran en los valores m??s simples respecto a los valores considerados en el sistema de categor??as creados, los cuales mayoritariamente vinculan la EA con un modelo conservacionista y con actividades puntuales, lo cual indica que lo que entiende los-as educadores-as ambientales sobre EA, suele estar 'identificado con el amor a la naturaleza, con las salidas fuera del aula, generalmente 'al campo', con la recogida de muestras o la realizaci??n de an??lisis o reciclado de papel' y 'ven la Educaci??n Ambiental como algo ajeno a las dem??s materias que se lleva a cabo en algunas determinadas fechas y que debe tener un curr??culo establecido y diferente del de otras materias, a excepci??n de las ciencias naturales, con las que de alguna manera se liga la Educaci??n Ambiental y aparece una alta relaci??n entre esta visi??n de la EA y la corriente inductivista del aprendizaje'.
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Resumen tomado de la publicaci??n
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In this paper, we consider the ATM networks in which the virtual path concept is implemented. The question of how to multiplex two or more diverse traffic classes while providing different quality of service requirements is a very complicated open problem. Two distinct options are available: integration and segregation. In an integration approach all the traffic from different connections are multiplexed onto one VP. This implies that the most restrictive QOS requirements must be applied to all services. Therefore, link utilization will be decreased because unnecessarily stringent QOS is provided to all connections. With the segregation approach the problem can be much simplified if different types of traffic are separated by assigning a VP with dedicated resources (buffers and links). Therefore, resources may not be efficiently utilized because no sharing of bandwidth can take place across the VP. The probability that the bandwidth required by the accepted connections exceeds the capacity of the link is evaluated with the probability of congestion (PC). Since the PC can be expressed as the CLP, we shall simply carry out bandwidth allocation using the PC. We first focus on the influence of some parameters (CLP, bit rate and burstiness) on the capacity required by a VP supporting a single traffic class using the new convolution approach. Numerical results are presented both to compare the required capacity and to observe which conditions under each approach are preferred
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Resumen del autor. Res??menes en espa??ol e ingl??s
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This paper proposes a pose-based algorithm to solve the full SLAM problem for an autonomous underwater vehicle (AUV), navigating in an unknown and possibly unstructured environment. The technique incorporate probabilistic scan matching with range scans gathered from a mechanical scanning imaging sonar (MSIS) and the robot dead-reckoning displacements estimated from a Doppler velocity log (DVL) and a motion reference unit (MRU). The proposed method utilizes two extended Kalman filters (EKF). The first, estimates the local path travelled by the robot while grabbing the scan as well as its uncertainty and provides position estimates for correcting the distortions that the vehicle motion produces in the acoustic images. The second is an augment state EKF that estimates and keeps the registered scans poses. The raw data from the sensors are processed and fused in-line. No priory structural information or initial pose are considered. The algorithm has been tested on an AUV guided along a 600 m path within a marina environment, showing the viability of the proposed approach
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Wavelength division multiplexing (WDM) networks have been adopted as a near-future solution for the broadband Internet. In previous work we proposed a new architecture, named enhanced grooming (G+), that extends the capabilities of traditional optical routes (lightpaths). In this paper, we compare the operational expenditures incurred by routing a set of demands using lightpaths with that of lighttours. The comparison is done by solving an integer linear programming (ILP) problem based on a path formulation. Results show that, under the assumption of single-hop routing, almost 15% of the operational cost can be reduced with our architecture. In multi-hop routing the operation cost is reduced in 7.1% and at the same time the ratio of operational cost to number of optical-electro-optical conversions is reduced for our architecture. This means that ISPs could provide the same satisfaction in terms of delay to the end-user with a lower investment in the network architecture
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Epipolar geometry is a key point in computer vision and the fundamental matrix estimation is the only way to compute it. This article surveys several methods of fundamental matrix estimation which have been classified into linear methods, iterative methods and robust methods. All of these methods have been programmed and their accuracy analysed using real images. A summary, accompanied with experimental results, is given