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排序方式: 共有3465条查询结果,搜索用时 15 毫秒
41.
Oliver Schreer Ingo Feldmann Isabel Alonso Mediavilla Pedro Concejero Abdul H. Sadka Mohammad Rafiq Swash Sergio Benini Riccardo Leonardi Tijana Janjusevic Ebroul Izquierdo 《Multimedia Tools and Applications》2010,48(1):23-49
Multimedia analysis and reuse of raw un-edited audio visual content known as rushes is gaining acceptance by a large number
of research labs and companies. A set of research projects are considering multimedia indexing, annotation, search and retrieval
in the context of European funded research, but only the FP6 project RUSHES is focusing on automatic semantic annotation,
indexing and retrieval of raw and un-edited audio-visual content. Even professional content creators and providers as well
as home-users are dealing with this type of content and therefore novel technologies for semantic search and retrieval are
required. In this paper, we present a summary of the most relevant achievements of the RUSHES project, focusing on specific
approaches for automatic annotation as well as the main features of the final RUSHES search engine. 相似文献
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Time series prediction is a complex problem that consists of forecasting the future behavior of a set of data with the only
information of the previous data. The main problem is the fact that most of the time series that represent real phenomena
include local behaviors that cannot be modelled by global approaches. This work presents a new procedure able to find predictable
local behaviors, and thus, attaining a better level of total prediction. This new method is based on a division of the input
space into Voronoi regions by means of Evolution Strategies. Our method has been tested using different time series domains.
One of them that represents the water demand in a water tank, through a long period of time. The other two domains are well
known examples of chaotic time series (Mackey-Glass) and natural phenomenon time series (Sunspot). Results prove that, in
most of cases, the proposed algorithm obtain better results than other algorithms commonly used. 相似文献
44.
MELM-GRBF: A modified version of the extreme learning machine for generalized radial basis function neural networks 总被引:3,自引:0,他引:3
Francisco Fernández-NavarroAuthor Vitae César Hervás-MartínezAuthor VitaeJavier Sanchez-MonederoAuthor Vitae Pedro Antonio GutiérrezAuthor Vitae 《Neurocomputing》2011,74(16):2502-2510
In this paper, we propose a methodology for training a new model of artificial neural network called the generalized radial basis function (GRBF) neural network. This model is based on generalized Gaussian distribution, which parametrizes the Gaussian distribution by adding a new parameter τ. The generalized radial basis function allows different radial basis functions to be represented by updating the new parameter τ. For example, when GRBF takes a value of τ=2, it represents the standard Gaussian radial basis function. The model parameters are optimized through a modified version of the extreme learning machine (ELM) algorithm. In the methodology proposed (MELM-GRBF), the centers of each GRBF were taken randomly from the patterns of the training set and the radius and τ values were determined analytically, taking into account that the model must fulfil two constraints: locality and coverage. An thorough experimental study is presented to test its overall performance. Fifteen datasets were considered, including binary and multi-class problems, all of them taken from the UCI repository. The MELM-GRBF was compared to ELM with sigmoidal, hard-limit, triangular basis and radial basis functions in the hidden layer and to the ELM-RBF methodology proposed by Huang et al. (2004) [1]. The MELM-GRBF obtained better results in accuracy than the corresponding sigmoidal, hard-limit, triangular basis and radial basis functions for almost all datasets, producing the highest mean accuracy rank when compared with these other basis functions for all datasets. 相似文献
45.
This paper presents a new approach to Particle Swarm Optimization, called Michigan Approach PSO (MPSO), and its application
to continuous classification problems as a Nearest Prototype (NP) classifier. In Nearest Prototype classifiers, a collection
of prototypes has to be found that accurately represents the input patterns. The classifier then assigns classes based on
the nearest prototype in this collection. The MPSO algorithm is used to process training data to find those prototypes. In
the MPSO algorithm each particle in a swarm represents a single prototype in the solution and it uses modified movement rules
with particle competition and cooperation that ensure particle diversity. The proposed method is tested both with artificial
problems and with real benchmark problems and compared with several algorithms of the same family. Results show that the particles
are able to recognize clusters, find decision boundaries and reach stable situations that also retain adaptation potential.
The MPSO algorithm is able to improve the accuracy of 1-NN classifiers, obtains results comparable to the best among other
classifiers, and improves the accuracy reported in literature for one of the problems.
相似文献
Pedro IsasiEmail: |
46.
Most real‐coded genetic algorithm research has focused on developing effective crossover operators, and as a result, many different types of crossover operators have been proposed. Some forms of crossover operators are more suitable to tackle certain problems than others, even at the different stages of the genetic process in the same problem. For this reason, techniques that combine multiple crossovers, called hybrid crossover operators, have been suggested as alternative schemes to the common practice of applying only one crossover model to all the elements in the population. On the other hand, there are operators with multiple offsprings, more than two descendants from two parents, which present a better behavior than the operators with only two descendants, and achieve a good balance between exploration and exploitation. © 2009 Wiley Periodicals, Inc. 相似文献
47.
In this work, we present an approach that introduces requirements traceability capabilities in the context of model-driven development of Web applications. This aspect allows us to define model-to-model transformations that not only provide a software artifact of lower abstraction (as model-to-model transformations usually do) but also to provide feedback about how they are applied. This feedback helps us to validate whether transformations are correctly applied. In particular, we present a model-to-model transformation that allows us to obtain navigational models of the Web engineering method OOWS from a requirements model. This transformation is defined as a set of mappings between these two models that have been implemented by means of graph transformations. The use of graph transformations allows us to develop a tool-supported strategy for applying mappings automatically. In addition, mechanisms for tracing requirements are also included in the definition of graph transformations. These mechanisms allow us to link each conceptual element to the requirements from which it is derived. In particular, we focus on tracing requirements throughout the navigational model, which describe the navigational structure of a Web application. To take advantage of these traceability mechanisms, we have developed a tool that obtains traceability reports after applying transformations. These reports help us to study aspects such as whether requirements are all supported, the impact of changing a requirement, or how requirements are modelled. 相似文献
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49.
Rita Cunha Carlos Silvestre João Hespanha A. Pedro AguiarAuthor vitae 《Automatica》2011,(5):1020-1027
This paper addresses the problem of stabilizing to a desired equilibrium point an eye-in-hand system, which consists of a single camera mounted on a rigid body free to move on . It is assumed that there is a collection of landmarks fixed in the environment and that the image coordinates of those landmarks are provided to the system by an on-board CCD camera. The proposed method addresses not only the problem of stabilization but also that of maintaining feature visibility along the system’s trajectory. The resulting solution consists of a feedback control law based on the current and desired image coordinates and reconstructed attitude and depth ratio information, which guarantees that (i) the desired equilibrium point is an almost global attractor; (ii) a set of necessary conditions for feature visibility holds throughout the system’s trajectories; and (iii) the image of a predefined feature point is kept inside the camera’s field of view. 相似文献
50.