Recursos de colección

Universidad Nacional de La Plata (74.538 recursos)

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vol. 07, no. 01

Mostrando recursos 1 - 19 de 19

  1. Sistema basado en redes neuronales digitales aplicado a la predicción climática en ambientes con microclima controlado

    Tosini, Marcelo Alejandro
    This thesis describes the design, implementation and evaluation of FPGA Architecture of a Digital ANN (Artificial Neural Networks) by using four components: data memory, weights memory, neuron module, and control unit. All these components have a generic orthogonal structure in order to facilitate automatic generation from specific parameters. In a particular ANN design all of its components are generated with specific size, depending on two types of parameters: A) Topological (number of inputs and number of hidden neurons) will determine the size of the memories, the neuron processing time and the microprogram size. B) Architectonic (i.e. word size in bits...

  2. Spherical layout

    Larrea, Martín Leonardo
    The goal of this work was centered in the graph visualization. The hope is that the extra dimension would give, literally, more space, and that this would ease the problem of displaying large structures. In spite of their apparent simplicity, the displaying of graphs in 3D can also introduce new problems that can be overcome with the appropriate interactions. So, we have developed a new visualization technique for 3D graph visualization; this includes the design of a new graph layout that we called spherical layout and the set of interactions that can be applied on this representation. This technique allows...

  3. Cellular outline segmentation using fractal estimators

    Salvatelli, Adrián; Caropresi, José; Delrieux, Claudio; Izaguirre, María F.; Casco, Víctor
    Segmentation in biological images is essential for the determination of biological parameters that allow the construction of models of several biological problems. This helps to establish clear relationships between those models and the parameter estimation, and for elaboration of key experiments that give support to biological theories. Segmentation is the process of qualitative or quantitative information extraction (shape, texture, physical and geometric properties, among others). These quantities are needed to compute the biological descriptors for further classification (v.g., cell counting, development stage assessment, and many others). This process is almost always supervised (i.e., human assisted), since the quality of the...

  4. Center selection techniques for metric indexes

    Mendoza Alric, Cristian; Herrera, Norma Edith
    The metric spaces model formalizes the similarity search concept in nontraditional databases. The goal is to build an index designed to save distance computations when answering similarity queries later. A large class of algorithms to build the index are based on partitioning the space in zones as compact as possible. Each zone stores a representative point, called center, and a few extra data that allow to discard the entire zone at query time without measuring the actual distance between the elements of the zone and the query object. The way in which the centers are selected affects the performance of...

  5. Toward integration of knowledge based systems and knowledge discovery systems

    Rancan, Claudio; Pesado, Patricia Mabel; García Martínez, Ramón
    This paper presents a proposal for an architecture that integrates knowledge discovery systems (automatic acquisition) and knowledge based systems (experts systems). This work formulates considerations over the viability of the implementation of this architecture according to the advance of the technologies involved.

  6. Framework for web application agile development

    Delía, Lisandro; Cáseres, Germán; Ramón, Hugo Dionisio; Thomas, Pablo Javier; Bertone, Rodolfo Alfredo
    Any system interacting with a data base requires modules capable of operating data stored in it. Its development times generally vary between 50 to 60 % of the time used for the application life cycle. The present paper describes the architecture and characteristics of a Framework for the agile generation of Web Applications, called PHP4DB. Its main objectives are to drastically reduce the job time, minimize errors, and tuning, as well as respect a homogeneous interface between each module. These characteristics allow the development team to focus and make emphasis on the tasks particular to the application domain. For a...

  7. The successful application of natural language processing for information retrieval

    Ferrández, Antonio; Rojas, Yenory; Peral, Jesús
    In this paper, a novel model for monolingual Information Retrieval in English and Spanish language is proposed. This model uses Natural Language Processing techniques (a POStagger, a Partial Parser, and an Anaphora Resolver) in order to improve the precision of traditional IR systems, by means of indexing the "entities" and the "relations" between these entities in the documents. This model is evaluated on both the Spanish and English CLEF corpora. For the English queries, there is a maximum increase of 35.11% in the average precision. For the Spanish queries, the maximum increase is 37.18%.

  8. CISNE-P: a global scheduling oriented to now environments

    Torchinsky, Matías; Hanzich, Mauricio; Hernández Budé, Porfidio; Luque Fadón, Emilio; Giné de Solà, Francesc; Solsona Theás, Francesc; Lérida Monsó, Josep Lluís
    In this work, we present an integral scheduling system for non-dedicated clusters, termed CISNE-P, which ensures the performance required by the local applications, while simultaneously allocating cluster resources to parallel jobs. Our approach solves the problem efficiently by using a social contract technique. This kind of technique is based on reserving computational resources, preserving a predetermined response time to local users. CISNE-P is a middleware which includes both a previously developed space-sharing job scheduler and a dynamic coscheduling system, a time sharing scheduling component. The experimentation performed in a Linux cluster shows that these two scheduler components are complementary and a...

  9. Directional continuous wavelet transform applied to handwritten numerals recognition using neural networks

    Romero, Diego J.; Seijas, Leticia; Ruedín, Ana M. C.
    The recognition of handwritten numerals has many important applications, such as automatic lecture of zip codes in post offices, and automatic lecture of numbers in checknotes. In this paper we present a preprocessing method for handwritten numerals recognition, based on a directional two dimensional continuous wavelet transform. The wavelet chosen is the Mexican hat. It is given a principal orientation by stretching one of its axes, and adding a rotation angle. The resulting transform has 4 parameters: scale, angle (orientation), and position (x,y) in the image. By fixing some of its parameters we obtain wavelet descriptors that form a feature...

  10. Interaction on graphs using non-conventional devices

    Escarza, Sebastián; Castro, Silvia Mabel; Martig, Sergio R.
    Interactions become essential in Visualization because they enable users to adapt the visual representation to their own needs allowing them to explore the underlying information space. By using non-conventional devices, they face a wider fan of interaction possibilities to explore their data. But, there is still not an agreed base theory to describe the processes involved in the visualization pipeline data transformation and, from the interaction viewpoint, it does not exist an interaction classification that allows presenting them under a unified perspective. The objective this work is to contribute to develop a Graph Visualization base classifying and defining the most...

  11. Computing support for problem solving in virtual communities of practice

    Casalini, María Clara; Estévez, Elsa Clara; Janowski, Tomasz
    The paper presents a formal model for a knowledge repository shared by members of a Virtual Community of Practice (VCPs), describes how the repository can be used to underpin collaborative problem solving, and how to build computer support for such processes. The repository comprises the resources used and developed by VCPs particularly through problem solving. As a case study, the paper illustrates how the problem solving process and the underlying repository can be applied in disaster prevention and handling. The repository and the process are formally described using the RAISE Specification Language.

  12. An ACO model for a non-stationary formulation of the single elevator problem

    Molina, Silvia; Leguizamón, Mario Guillermo; Alba Torres, Enrique
    The Ant Colony Optimization (ACO) metaheuristic is a bio-inspired approach for hard combinatorial optimization problems for stationary and non-stationary environments. In the ACO metaheuristic, a colony of artificial ants cooperate for finding high quality solutions in a reasonable time. An interesting example of a non-stationary combinatorial optimization problem is the Multiple Elevators Problem (MEP) which consists in finding a sequence of movements for each elevator to perform in a building so that to minimize, for instance, the users waiting average time. Events like the arrival of one new user to the elevator queue or the fault of one elevator dynamically...

  13. A model for the automatic mapping of tasks to processors in heterogeneous multi-cluster architectures

    De Giusti, Laura Cristina; Chichizola, Franco; Naiouf, Marcelo; Ripoll, Ana; De Giusti, Armando Eduardo
    This paper discusses automatic mapping methods for concurrent tasks to processors applying graph analysis for the relation among tasks, in which processing and communicating times are incorporated. Starting by an analysis in which processors are homogeneous and data transmission times do not depend on the processors that are communicating (a typical case in homogeneous clusters), we progress to extend the model to heterogeneous processors having the possibility of different communication levels, applicable to a multicluster. Some results obtained with the model and future work lines are presented, particularly, the possibility of obtaining the required optimal number of processors, keeping a...

  14. A lightweight method for computing ball spin in real time

    Cristina, Federico; Dapoto, Sebastián H.; Russo, Claudia Cecilia
    The present paper poses a new method for computing the rotation of a ball in sport training situations, when the ball is approaching the goal line. The proposed method significantly reduces the hardware requirements associated to the capture, as well as the computational complexity necessary to obtain the results. The system's objective is to improve the player's technique and training methodology, and it is treated within the scope of the Institute's research line on signal and image processing areas. Experimental results will be presented using digitally generated images.

  15. Process tracking for dynamic tuning applications on the grid

    Costa, Genaro; Morajko, Anna; Margalef, Tomás; Luque Fadón, Emilio
    The computational resources need by the scientific community to solve problems is beyond the current available infrastructure. Performance requirements are needed due constant research progress, new problems studies or detail increase of the current ones. Users create new wide distributed systems such as computational Grids to achieve desired performance goals. Grid systems are generally built on top of available computational resources as cluster, parallel machines or storage devices distributed within different organizations and those resources are interconnected by a network. Application tuning on Grid environment is a hard task due system characteristics like multi-cluster job distribution among different local schedulers...

  16. An inference mechanism for question answering

    Roger, Sandra; Ferrández, Sergio; López Moreno, Pilar; Peral, Jesús
    This work describes an inference mechanism applied to AliQAn Question Answering System for Spanish in open domain. AliQAn is based fundamentally on the use of syntactic patterns to identify the possible answers. An inference mechanism is applied to the questions set of economic type. In this way, our system improves the accuracy of this question type from 33% to 57%.

  17. Evacuation simulations using cellular automata

    Tissera, Pablo Cristian; Printista, Alicia Marcela; Errecalde, Marcelo Luis
    Computer simulations using Cellular Automata (CA) have been applied with considerable success in diferent scientific areas, such as chemistry, biochemistry, economy, physics, etc. In this work we use CA in order to specify and implement a simulation model that allows to investigate behavioral dynamics for pedestrians in an emergency evacuation. In particular, we will concentrate on those cases that involve the forced evacuation of a large number of people due to the threat of the fire, within a building with a specific number of exits. The work includes a brief introduction to the main concepts of CA that were considered...

  18. Spatial selection of sparse pivots for similarity search in metric spaces

    Rodríguez Brisaboa, Nieves; Fariña, Antonio; Pedreira, Óscar; Reyes, Nora Susana
    Similarity search is a fundamental operation for applications that deal with unstructured data sources. In this paper we propose a new pivot-based method for similarity search, called Sparse Spatial Selection (SSS). The main characteristic of this method is that it guarantees a good pivot selection more efficiently than other methods previously proposed. In addition, SSS adapts itself to the dimensionality of the metric space we are working with, without being necessary to specify in advance the number of pivots to use. Furthermore, SSS is dynamic, that is, it is capable to support object insertions in the database efficiently, it can work...

  19. Improving radar visualization system

    Acosta, Nelson; Tosini, Marcelo Alejandro; Mezzanotte, Martín F.; Tommasi, M. Carolina
    This work develops a system to visualize the information for radar systems interfaces. It is a flexible, portable software system that allows to be used for radars that have different technologies and that is able to be adapted to the specific needs of each aplication domain in an eficient way. Replacing the visualization and processing units on existing radar platforms by this new system, a practical and inexpensive improvement is achieved.

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