982 resultados para Synthetic traffic generation


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In this paper we propose an innovative method for the automatic detection and tracking of road traffic signs using an onboard stereo camera. It involves a combination of monocular and stereo analysis strategies to increase the reliability of the detections such that it can boost the performance of any traffic sign recognition scheme. Firstly, an adaptive color and appearance based detection is applied at single camera level to generate a set of traffic sign hypotheses. In turn, stereo information allows for sparse 3D reconstruction of potential traffic signs through a SURF-based matching strategy. Namely, the plane that best fits the cloud of 3D points traced back from feature matches is estimated using a RANSAC based approach to improve robustness to outliers. Temporal consistency of the 3D information is ensured through a Kalman-based tracking stage. This also allows for the generation of a predicted 3D traffic sign model, which is in turn used to enhance the previously mentioned color-based detector through a feedback loop, thus improving detection accuracy. The proposed solution has been tested with real sequences under several illumination conditions and in both urban areas and highways, achieving very high detection rates in challenging environments, including rapid motion and significant perspective distortion

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RDB to RDF Mapping Language (R2RML) es una recomendación del W3C que permite especificar reglas para transformar bases de datos relacionales a RDF. Estos datos en RDF se pueden materializar y almacenar en un sistema gestor de tripletas RDF (normalmente conocidos con el nombre triple store), en el cual se pueden evaluar consultas SPARQL. Sin embargo, hay casos en los cuales la materialización no es adecuada o posible, por ejemplo, cuando la base de datos se actualiza frecuentemente. En estos casos, lo mejor es considerar los datos en RDF como datos virtuales, de tal manera que las consultas SPARQL anteriormente mencionadas se traduzcan a consultas SQL que se pueden evaluar sobre los sistemas gestores de bases de datos relacionales (SGBD) originales. Para esta traducción se tienen en cuenta los mapeos R2RML. La primera parte de esta tesis se centra en la traducción de consultas. Se propone una formalización de la traducción de SPARQL a SQL utilizando mapeos R2RML. Además se proponen varias técnicas de optimización para generar consultas SQL que son más eficientes cuando son evaluadas en sistemas gestores de bases de datos relacionales. Este enfoque se evalúa mediante un benchmark sintético y varios casos reales. Otra recomendación relacionada con R2RML es la conocida como Direct Mapping (DM), que establece reglas fijas para la transformación de datos relacionales a RDF. A pesar de que ambas recomendaciones se publicaron al mismo tiempo, en septiembre de 2012, todavía no se ha realizado un estudio formal sobre la relación entre ellas. Por tanto, la segunda parte de esta tesis se centra en el estudio de la relación entre R2RML y DM. Se divide este estudio en dos partes: de R2RML a DM, y de DM a R2RML. En el primer caso, se estudia un fragmento de R2RML que tiene la misma expresividad que DM. En el segundo caso, se representan las reglas de DM como mapeos R2RML, y también se añade la semántica implícita (relaciones de subclase, 1-N y M-N) que se puede encontrar codificada en la base de datos. Esta tesis muestra que es posible usar R2RML en casos reales, sin necesidad de realizar materializaciones de los datos, puesto que las consultas SQL generadas son suficientemente eficientes cuando son evaluadas en el sistema gestor de base de datos relacional. Asimismo, esta tesis profundiza en el entendimiento de la relación existente entre las dos recomendaciones del W3C, algo que no había sido estudiado con anterioridad. ABSTRACT. RDB to RDF Mapping Language (R2RML) is a W3C recommendation that allows specifying rules for transforming relational databases into RDF. This RDF data can be materialized and stored in a triple store, so that SPARQL queries can be evaluated by the triple store. However, there are several cases where materialization is not adequate or possible, for example, if the underlying relational database is updated frequently. In those cases, RDF data is better kept virtual, and hence SPARQL queries over it have to be translated into SQL queries to the underlying relational database system considering that the translation process has to take into account the specified R2RML mappings. The first part of this thesis focuses on query translation. We discuss the formalization of the translation from SPARQL to SQL queries that takes into account R2RML mappings. Furthermore, we propose several optimization techniques so that the translation procedure generates SQL queries that can be evaluated more efficiently over the underlying databases. We evaluate our approach using a synthetic benchmark and several real cases, and show positive results that we obtained. Direct Mapping (DM) is another W3C recommendation for the generation of RDF data from relational databases. While R2RML allows users to specify their own transformation rules, DM establishes fixed transformation rules. Although both recommendations were published at the same time, September 2012, there has not been any study regarding the relationship between them. The second part of this thesis focuses on the study of the relationship between R2RML and DM. We divide this study into two directions: from R2RML to DM, and from DM to R2RML. From R2RML to DM, we study a fragment of R2RML having the same expressive power than DM. From DM to R2RML, we represent DM transformation rules as R2RML mappings, and also add the implicit semantics encoded in databases, such as subclass, 1-N and N-N relationships. This thesis shows that by formalizing and optimizing R2RML-based SPARQL to SQL query translation, it is possible to use R2RML engines in real cases as the resulting SQL is efficient enough to be evaluated by the underlying relational databases. In addition to that, this thesis facilitates the understanding of bidirectional relationship between the two W3C recommendations, something that had not been studied before.

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The carbohydrate antigen globo H commonly found on breast cancer cells is a potential target for vaccine therapy. The objectives of this trial were to determine the toxicity and immunogenicity of three synthetic globo H-keyhole limpet hemocyanin conjugates plus the immunologic adjuvant QS-21. Twenty-seven metastatic breast cancer patients received five vaccinations each. The vaccine was well tolerated, and no definite differences were observed among the three formulations. Serologic analyses demonstrated the generation of IgM antibody titers in most patients, with minimal IgG antibody stimulation. There was significant binding of IgM antibodies to MCF-7 tumor cells in 16 patients, whereas IgG antibody reactivity was observed in a few patients. There was evidence of complement-dependent cytotoxicity in several patients. Affinity column purification supported the specificity of IgM antibodies for globo H. On the basis of these data, globo H will constitute one component of a polyvalent vaccine for evaluation in high-risk breast cancer patients.

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We have developed a system for generation of infectious bursal disease virus (IBDV), a segmented double-stranded RNA virus of the Birnaviridae family, with the use of synthetic transcripts derived from cloned cDNA. Independent full-length cDNA clones were constructed that contained the entire coding and noncoding regions of RNA segments A and B of two distinguishable IBDV strains of serotype I. Segment A encodes all of the structural (VP2, VP4, and VP3) and nonstructural (VP5) proteins, whereas segment B encodes the RNA-dependent RNA polymerase (VP1). Synthetic RNAs of both segments were produced by in vitro transcription of linearized plasmids with T7 RNA polymerase. Transfection of Vero cells with combined plus-sense transcripts of both segments generated infectious virus as early as 36 hr after transfection. The infectivity and specificity of the recovered chimeric virus was ascertained by the appearance of cytopathic effect in chicken embryo cells, by immunofluorescence staining of infected Vero cells with rabbit anti-IBDV serum, and by nucleotide sequence analysis of the recovered virus, respectively. In addition, transfectant viruses containing genetically tagged sequences in either segment A or segment B of IBDV were generated to confirm the feasibility of this system. The development of a reverse genetics system for double-stranded RNA viruses will greatly facilitate studies of the regulation of viral gene expression, pathogenesis, and design of a new generation of live vaccines.

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Although the evolutionary success of polyploidy in higher plants has been widely recognized, there is virtually no information on how polyploid genomes have evolved after their formation. In this report, we used synthetic polyploids of Brassica as a model system to study genome evolution in the early generations after polyploidization. The initial polyploids we developed were completely homozygous, and thus, no nuclear genome changes were expected in self-fertilized progenies. However, extensive genome change was detected by 89 nuclear DNA clones used as probes. Most genome changes involved loss and/or gain of parental restriction fragments and appearance of novel fragments. Genome changes occurred in each generation from F2 to F5, and the frequency of change was associated with divergence of the diploid parental genomes. Genetic divergence among the derivatives of synthetic polyploids was evident from variation in genome composition and phenotypes. Directional genome changes, possibly influenced by cytoplasmic-nuclear interactions, were observed in one pair of reciprocal synthetics. Our results demonstrate that polyploid species can generate extensive genetic diversity in a short period of time. The occurrence and impact of this process in the evolution of natural polyploids is unknown, but it may have contributed to the success and diversification of many polyploid lineages in both plants and animals.

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Construction of synthetic combinatorial libraries is described that allows for the generation of a library of motifs rather than a library of compounds. Peptide libraries based on this strategy were synthesized and screened with model targets streptavidin and anti-beta-endorphin antibody. The screens resulted in observation of expected motifs providing evidence of the effectiveness of the suggested approach.

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Final report (SW-508) describing work performed for the Federal Solid waste management program under Contract no. 68-01-2684.

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Federal Highway Administration, Office of Safety and Traffic Operations Research and Development, McLean, Va.

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National Highway Traffic Safety Administration, Office of Heavy Duty Vehicle Research, Washington, D.C.

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Federal Highway Administration, Implementation Division, Washington, D.C.

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In a genome-wide RNA-mediated interference screen for genes required in membrane traffic - including endocytic uptake, recycling from endosomes to the plasma membrane, and secretion - we identified 168 candidate endocytosis regulators and 100 candidate secretion regulators. Many of these candidates are highly conserved among metazoans but have not been previously implicated in these processes. Among the positives from the screen, we identified PAR-3, PAR-6, PKC-3 and CDC-42, proteins that are well known for their importance in the generation of embryonic and epithelial-cell polarity. Further analysis showed that endocytic transport in Caenorhabditis elegans coelomocytes and human HeLa cells was also compromised after perturbation of CDC-42/Cdc42 or PAR-6/Par6 function, indicating a general requirement for these proteins in regulating endocytic traffic. Consistent with these results, we found that tagged CDC-42/Cdc42 is enriched on recycling endosomes in C. elegans and mammalian cells, suggesting a direct function in the regulation of transport.

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Ad hoc wireless sensor networks (WSNs) are formed from self-organising configurations of distributed, energy constrained, autonomous sensor nodes. The service lifetime of such sensor nodes depends on the power supply and the energy consumption, which is typically dominated by the communication subsystem. One of the key challenges in unlocking the potential of such data gathering sensor networks is conserving energy so as to maximize their post deployment active lifetime. This thesis described the research carried on the continual development of the novel energy efficient Optimised grids algorithm that increases the WSNs lifetime and improves on the QoS parameters yielding higher throughput, lower latency and jitter for next generation of WSNs. Based on the range and traffic relationship the novel Optimised grids algorithm provides a robust traffic dependent energy efficient grid size that minimises the cluster head energy consumption in each grid and balances the energy use throughout the network. Efficient spatial reusability allows the novel Optimised grids algorithm improves on network QoS parameters. The most important advantage of this model is that it can be applied to all one and two dimensional traffic scenarios where the traffic load may fluctuate due to sensor activities. During traffic fluctuations the novel Optimised grids algorithm can be used to re-optimise the wireless sensor network to bring further benefits in energy reduction and improvement in QoS parameters. As the idle energy becomes dominant at lower traffic loads, the new Sleep Optimised grids model incorporates the sleep energy and idle energy duty cycles that can be implemented to achieve further network lifetime gains in all wireless sensor network models. Another key advantage of the novel Optimised grids algorithm is that it can be implemented with existing energy saving protocols like GAF, LEACH, SMAC and TMAC to further enhance the network lifetimes and improve on QoS parameters. The novel Optimised grids algorithm does not interfere with these protocols, but creates an overlay to optimise the grids sizes and hence transmission range of wireless sensor nodes.

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Next-generation networks are likely to be non-uniform in all their aspects, including number of lightpaths carried per link, number of wavelengths per link, number of fibres per link, asymmetry of the links, and traffic flows. Routing and wavelength allocation models generally assume that the optical network is uniform and that the number of wavelengths per link is a constant. In practice however, some nodes and links carry heavy traffic and additional wavelengths are needed in those links. We study a wavelength-routed optical network based on the UK JANET topology where traffic demands between nodes are assumed to be non-uniform. We investigate how network capacity can be increased by locating congested links and suggesting cost-effective upgrades. Different traffic demands patterns, hop distances, number of wavelengths per link, and routing algorithms are considered. Numerical results show that a 95% increase in network capacity is possible by overlaying fibre on just 5% of existing links. We conclude that non-uniform traffic allocation can be beneficial to localize traffic in nodes and links deep in the network core and provisioning of additional resources there can efficiently and cost-effectively increase network capacity. © 2013 IEEE.