3,903 research outputs found
Comparison of Balancing Techniques for Multimedia IR over Imbalanced Datasets
A promising method to improve the performance of information retrieval systems is to approach retrieval tasks as a supervised classification problem. Previous user interactions, e.g. gathered from a thorough log file analysis, can be used to train classifiers which aim to inference relevance of retrieved documents based on user interactions. A problem in this approach is, however, the large imbalance ratio between relevant and non-relevant documents in the collection. In standard test collection as used in academic evaluation frameworks such as TREC, non-relevant documents outnumber relevant documents by far. In this work, we address this imbalance problem in the multimedia domain. We focus on the logs of two multimedia user studies which are highly imbalanced. We compare a naiinodotve solution of randomly deleting documents belonging to the majority class with various balancing algorithms coming from different fields: data classification and text classification. Our experiments indicate that all algorithms improve the classification performance of just deleting at random from the dominant class
Poor performance of mutual funds in Spain. 1991-2007
Over the past 10 and 16 years, the average return on mutual funds in Spain was lower than the average return on government bonds at any term. Over the past 10 years, the average return on the funds was lower than inflation. In spite of these results, on December 31, 2007, 8,264,240 investors held 238.7 billion euros in the 2,907 mutual funds then in existence. During 2007, the number of shareholders fell by 555,569 and the value of their assets, by 6.1%. Only 30 of the 935 mutual funds with a 10-year history outperformed the benchmark and only two of them outperformed the overall index of the Madrid Stock Exchange (ITBM). If in the past 16 years every mutual fund had achieved the benchmark return for its category, the gain in value would have been 180 billion euros, instead of the actual figure of 80 billion euros. Total fees and other expenses for the period amounted to 34 billion euros.mutual funds; return to shareholders; benchmark; appreciation of the funds:
Layers of powers: societies and institutions in Europe
Historians and social scientists have offered many and varied definitions of the term “community”. This chapter focuses on specific examples of face-to-face or local communities in order to test the possibilities and limits of the two major analytical approaches to communities: an anthropological approach which identifies ‘community’ as an organic entity, and a symbolic one which considers feelings of belonging and self-identification as constitutive aspects of a community. In this quest, close attention is paid to the question of the stabilization of community’s structures through legislation and institutions, a process that integrates such micro-societies into broader networks of power, and renders them visible to historians. In the first section we examine what we have called a “world of communities”, from periods when communities constituted the dominant element of social structure. Examining ancient Jewish and medieval Icelandic communities, and then early modern Irish and Scottish clans, we try to identify their basic characteristics and to reconstruct the way they related to the rest of the social structure. The second section analyzes the emergence of new loyalties and models of social membership from the 19th century onwards, emphasizing how the discourse on communities played a crucial role in the construction of these diverse patterns of identification and differentiation. Finally, we explore the permanence of the communitarian world supposedly replaced by nationalism and other major modern ideologies along with the new meanings and uses of communities in the 20th and 21st centuries. In sum, this broad overview provides a preliminary narrative of the changes in the structures of communities and their shifting position within wider patterns of social organizations while drawing attention to parallel transformations in theoretical reflection on communities
A very high resolution X- and Ku-band field study of a barley crop in support of the SWINTOL Project
SAR Wave INteraction for Natural Targets Over Land (SWINTOL) is a project funded by the European Space Agency. The study’s goal is to better understand the interaction of high frequency radar (> X-band) with vegetation and soils, in order to drive the development of a high-frequency electromagnetic model to simulate SAR imagery at high resolution (< 1 m). Existing models work well at C and X band frequencies, but do not work properly at higher frequencies. Cranfield University’s role in this project was to provide the field data necessary for model validation and development. Radar imagery was taken of a barley crop over an entire growing season. The portable outdoor GB-SAR system used the tomographic profiling (TP) technique to capture polarimetric imagery of the crop. TP is a scheme that provides detailed maps of the vertical backscatter pattern through a crop canopy, along a narrow transect directly beneath the radar platform. Fully-polarimetric imagery was obtained across overlapping 6.5 GHz bandwidths over the X- and Ku-band frequency range 8-20 GHz. This gave the opportunity to see the detailed scattering behaviour within the crop at the plant component level, from emergence of the crop through to harvesting. In combination with the imagery, full bio-geophysical characterisation of the crop and soil was made on each measurement date. Surface roughness characterisation of the soil was captured using a 3D optical stereoscopic system. This work details the measurements made, and provides a comparative assessment of the results in terms of understanding the backscatter in relation to biophysical and radar parameters
DOC 2017-03 International and Intercultural Leadership Certificate
Legislative Authority; Art. III. B. 1-7; DOC 2015-0
Livestock rational use of Anaga Rural Park. Preliminary results
Anaga Rural Park is a natural protected space that is situated in the northeast of Tenerife isle in Canary Islands. With a 14.224 hectares, it’s characterised by high ecosystems diversity, debt to high incline that condition the coexistence of different ecological floors. This situation has determined the uses types of the local resources and the grazing. In this way, the study in the Anaga Rural Park, try to design specific strategy for the rational use of the natural resources in the zone. The methodology used is based on individuals interwievs and geographic information processing, with purpose to define the average stocking rate, annual distribution of stocking rate and animal production systems characteristics in Anaga Rural Park. After to analyse the secondary information, the interwievs realised and the direct observations of the productions systems, we have obtained enough data to locate the zone breed reality of the zone a make and unreliable outline of the production systems in Anaga.El Parque Rural de Anaga es un espacio natural protegido que se encuentra en el noreste de la Isla de Tenerife, en las Islas Canarias. Con unas dimensiones de 14.000 ha, se caracteriza por una alta diversidad de ecosistemas debido a las altas pendientes que condicionan la existencia de diferentes pisos ecológicos. Esto ha determinado las formas de aprovechamiento de los recursos locales en general y del pastoreo en particular. En este sentido, el estudio en el Parque Rural Anaga, trata de diseñar estrategias concretas para el uso racional de los recursos naturales en la zona. La metodología utilizada se basa en las entrevistas individuales y el tratamiento de información geográfica, con el fin de definir la Carga ganadera promedio, la distribución anual de la Carga ganadera y las características de los sistemas de producción animal en el Parque Rural de Anaga. Tras el análisis de la información secundaria, las entrevistas realizadas y la observación directa de los sistemas de producción, se han obtenido suficientes datos como para ubicarnos en la realidad ganadera de la zona y por tanto hacer un esbozo fiable de la situación de los sistemas de producción en Anaga
Mecanismos de transducción del lipopolisacárido
The lipopolysaccharide, a component of the Gram negative bacteria wall, is the principal agent causing septic shock.Once in the blood stream, the lipopolysaccharide activates contact systems and stimulates different types of cell throughrecognition molecules, such as CD14 and the recently described TLR receptors, triggering diverse interacting transductionpathways. The MAP kinase pathway and the TLR cascade are highlighted as prevalent factors, which in turn, act upontranscription factors. One of the main nuclear factors is NF-κB, which has a fundamental role in the induction ofenzymes involved in the production of cytokins and autacoids, such as inducible nitric oxide synthase or induciblecyclooxygenase. The increase in production of nitric oxide, tromboxanes, prostaglandins and other vasoactive agents,derived from the synthesised enzymes, gives rise to serious cardiovascular disorders characteristic of septic shock.El lipopolisacárido, componente de la pared de las bacterias Gram negativas, es el principal agente causante delshock séptico. Una vez en el torrente sanguíneo, el lipopolisacárido activa los sistemas de contacto y estimuladiferentes tipos celulares mediante moléculas de reconocimiento como el CD14 y los recientemente conocidos receptoresTLR, disparando diversas vías de transducción que interaccionan entre sí. Dentro de éstas destacan la vía delas MAP kinasas y la cascada de los TLR, que a su vez actúan sobre factores de transcripción. Uno de los principalesfactores nucleares es el NF-κB, con un papel fundamental en la inducción de enzimas implicadas en la producciónde citokinas y autacoides, tales como la óxido nítrico sintasa o la ciclooxigenasa inducibles. El aumento en laproducción de óxido nítrico, tromboxanos, prostaglandinas y otros agentes vasoactivos derivados de las enzimassintetizadas da lugar a las graves alteraciones cardiovasculares características del shock séptico
The Physics of Liquid Para-Hydrogen
Macroscopic systems of hydrogen molecules exhibit a rich thermodynamic phase
behavior. Due to the simplicity of the molecular constituents a detailed
exploration of the thermal properties of these boson systems at low
temperatures is of fundamental interest. Here,we report theoretical and
experimental results on various spatial correlation functions and corresponding
distributions in momentum space of liquid para-hydrogen close to the triple
point. They characterize the structure of the correlated liquid and provide
information on quantum effects present in this Bose fluid. Numerical
calculations employ Correlated Density-Matrix(CDM)theory and Path-Integral
Monte-Carlo(PIMC)simulations. A comparison of these theoretical results
demonstrates the accuracy of CDM theory. This algorithm therefore permits a
fast and efficient quantitative analysis of the normal phase of liquid
para-hydrogen.We compare and discuss the theoretical results with available
experimental data.Comment: 14 pages, 7 figure
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