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971.
Answering questions with an <Emphasis Type="Italic">n</Emphasis>-gram based passage retrieval engine
Davide Buscaldi Paolo Rosso José Manuel Gómez-Soriano Emilio Sanchis 《Journal of Intelligent Information Systems》2010,34(2):113-134
In this paper, we present a Question Answering system based on redundancy and a Passage Retrieval method that is specifically
oriented to Question Answering. We suppose that in a large enough document collection the answer to a given question may appear
in several different forms. Therefore, it is possible to find one or more sentences that contain the answer and that also
include tokens from the original question. The Passage Retrieval engine is almost language-independent since it is based on
n-gram structures. Question classification and answer extraction modules are based on shallow patterns. 相似文献
972.
Marco Tarini Nico Pietroni Paolo Cignoni Daniele Panozzo Enrico Puppo 《Computer Graphics Forum》2010,29(2):407-418
In this paper we present an innovative approach to incremental quad mesh simplification, i.e. the task of producing a low complexity quad mesh starting from a high complexity one. The process is based on a novel set of strictly local operations which preserve quad structure. We show how good tessellation quality (e.g. in terms of vertex valencies) can be achieved by pursuing uniform length and canonical proportions of edges and diagonals. The decimation process is interleaved with smoothing in tangent space. The latter strongly contributes to identify a suitable sequence of local modification operations. The method is naturally extended to manage preservation of feature lines (e.g. creases) and varying (e.g. adaptive) tessellation densities. We also present an original Triangle‐to‐Quad conversion algorithm that behaves well in terms of geometrical complexity and tessellation quality, which we use to obtain the initial quad mesh from a given triangle mesh. 相似文献
973.
Query processing issues in region-based image databases 总被引:1,自引:0,他引:1
Many modern image database systems adopt a region-based paradigm, in which images are segmented into homogeneous regions in order to improve the retrieval accuracy. With respect
to the case where images are dealt with as a whole, this leads to some peculiar query processing issues that have not been
investigated so far in an integrated way. Thus, it is currently hard to understand how the different alternatives for implementing
the region-based image retrieval model might impact on performance. In this paper, we analyze in detail such issues, in particular
the type of matching between regions (either one-to-one or many-to-many). Then, we propose a novel ranking model, based on the concept of Skyline,
as an alternative to the usual one based on aggregation functions and k-Nearest Neighbors queries. We also discuss how different query types can be efficiently supported. For all the considered
scenarios we detail efficient index-based algorithms that are provably correct. Extensive experimental analysis shows, among
other things, that: (1) the 1–1 matching type has to be preferred to the N–M one in terms of efficiency, whereas the two have comparable effectiveness, (2) indexing regions rather than images performs
much better, and (3) the novel Skyline ranking model is consistently the most efficient one, even if this sometimes comes
at the price of a reduced effectiveness. 相似文献
974.
Marin Guenov Paolo Fantini Libish Balachandran Jeremy Maginot Mattia Padulo Marco Nunez 《Journal of Intelligent and Robotic Systems》2010,59(3-4):223-240
Presented is a novel framework for performing flexible computational design studies at preliminary design stage. It incorporates a workflow management device (WMD) and a number of advanced numerical treatments, including multi-objective optimization, sensitivity analysis and uncertainty management with emphasis on design robustness. The WMD enables the designer to build, understand, manipulate and share complex processes and studies. Results obtained after applying the WMD on various test cases, showed a significant reduction of the iterations required for the convergence of the computational system. The tests results also demonstrated the capabilities of the advanced treatments as follows: The novel procedure for global multi-objective optimization has the unique ability to generate well-distributed Pareto points on both local and global Pareto fronts simultaneously. The global sensitivity analysis procedure is able to identify input variables whose range of variation does not have significant effect on the objectives and constraints. It was demonstrated that fixing such variables can greatly reduce the computational time while retaining a satisfactory quality of the resulting Pareto front. The novel derivative-free method for uncertainty propagation, which was proposed for enabling multi-objective robust optimization, delivers a higher accuracy compared to the one based on function linearization, without altering significantly the cost of the single optimization step. The work demonstrated for the first time that such capabilities can be used in a coordinated way to enhance the efficiency of the computational process and the effectiveness of the decision making at preliminary design stage. 相似文献
975.
Yogesh Singh Paolo Ferrazzoli Rachid Rahmoune 《International journal of remote sensing》2013,34(14):4967-4985
In this work, Advanced Microwave Scanning Radiometer Earth Observing System (AMSR-E) signatures were analysed over some critical sites in Lakhimpur District in Brahmaputra basin, India, characterized by a high frequency of flooding events. The site is mostly covered by paddy fields. Results obtained were compared with water level measurements in three stations close to the main channel of the river. Information about surface temperature, which allowed us to estimate the emissivity, was also available. Investigations were carried out at the C, X, and Ka bands of the AMSR-E channel. A multi-frequency analysis indicated that the X band would represent a good compromise between resolution and sensitivity requirements, while at the C band the resolution was too coarse and at the Ka band the signatures were affected by raindrops. Samples collected during rain were eliminated using techniques based on the 89.0 GHz channel. However, even after this correction, the Ka band showed poor sensitivity due to higher attenuation by vegetation. The correlations between different pairs of variables, viz. polarization index (PI), water level (WL), and fractional water surface area (F WS), were also investigated. At the X band, the water level was better correlated with the PI than with emissivity and other parameters defined in the literature. The correlation was good in cases of slow variation in WL. In cases of sudden variation in the river, the PI followed the variations with some time delay related to the propagation of water within the covered AMSR-E pixel. 相似文献
976.
Paolo Bonavoglia 《Cryptologia》2013,37(6):459-465
AbstractIn his 1553 paper Giovan Battista Bellaso presented his first polyalphabetic cipher, writing that this was an improved reprint of a previous cipher of 1552 that had been printed in Venice on a loose leaflet without instructions. There was much speculation about this early cipher, since no print of that cipher was reported to have been found. Now a printed copy of that leaflet has been found in Venice by the author, and this paper is a report of that finding. 相似文献
977.
Stefan Rank Steve Hoffmann Hans-Georg Struck Ulrike Spierling Simon Mayr Paolo Petta 《Applied Artificial Intelligence》2013,27(6):629-645
Autonomous characters in interactive storytelling can be supported by using affective agent architectures. The configuration of most current tools for controlling agents is, however, implementation specific and not tailored to the needs of authors. Based on literature review, a questionnaire evaluation of authors’ preferences for character creation, and a case study of an author’s conceptualization of this process, we investigate the different methods of configuration available in current agent architectures, reviewing discrepancies and matches. Given these relations, promising approaches to configuration are identified, based on initial inner states, “global” parameters of characters, libraries of stock characters, and selections of backstory experiences. 相似文献
978.
This paper describes the feasibility study for the restoration of agricultural land with a tendency to become waterlogged into a natural wetland, conceived to mitigate floods and to remove nutrients from the water drained from the cultivated plots. The wetland model, developed in aquatox, includes the nutrient dynamics both in the water and in the sediment, and the vegetation that is expected to develop as a consequence of flooding. The model inputs were synthesized from historical time series of rainfall and chemical data collected over the last decade. The model outputs are used to compute a synthetic fuzzy quality index (FQI) to assess the removal efficiency of the wetland. This FQI is based on three main variables describing the ecosystem quality: chlorophyll-a, dissolved oxygen and total suspended solids. This index has the merit of being simple enough to be immediately grasped by non-technical people, like managers and stakeholders, to whom the restoration project is proposed. The simulations, performed under five differing loading scenarios demonstrate the feasibility of this solution, which is robust enough to accommodate a 50% increase in either nitrogen, phosphorous or organic matter. 相似文献
979.
A primary challenge in the mobile Internet scenario is the dynamic differentiation of provided levels of Quality of Service (QoS) depending on client characteristics and current resource availability. In this context, the paper presents how the application-level ubiQoS middleware supports the provisioning of audio applications with different QoS levels over the last Bluetooth segment to wireless devices. To this purpose, ubiQoS dynamically deploys mobile proxies, acting as masters in Bluetooth piconets, to properly configure and manage Bluetooth connections at runtime. Audio applications working on top of ubiQoS can easily exploit differentiated QoS by simply specifying different user classes and terminal profiles. ubiQoS proxies exploit JSR82ext, a newly developed Java library that extends the JSR82 specification for Java-based Bluetooth communication facilities with richer QoS management functions for all types of Bluetooth connections. The reported experimental results show that our Java-based implementation can dynamically support differentiated QoS levels for audio traffic, with an efficient usage of the available Bluetooth bandwidth. 相似文献
980.
Millioni R Iori E Puricelli L Arrigoni G Vedovato M Trevisan R James P Tiengo A Tessari P 《Proteomics. Clinical applications》2008,2(4):492-503
Diabetic nephropathy (DN) develops in about 40% of insulin-dependent type 1 diabetes mellitus (T1DM) patients, and is associated not only with diabetes duration and metabolic control, but also with a genetic predisposition. Constitutive alterations of cytoskeletal proteins may play a role in the development of DN. We investigated the expression of these proteins in cultured skin fibroblasts, obtained from long-term T1DM patients with and without DN but comparable metabolic control, and from matched healthy subjects, by means of 2-DE electrophoresis and MS-MALDI analyses. In T1DM with DN, compared to the other two groups, quantitative analyses revealed an altered expression of 17 spots (p<0.05-p<0.01), corresponding to 12 unique proteins. In T1DM with DN, beta-actin and three isoforms of tubulin beta-2 chain, tropomodulin-3, and LASP-1 were decreased, whereas two tubulin beta-4 chain isoforms, one alpha actinin-4 isoform, membrane-organizing extension spike protein (MOESIN), FLJ00279 (corresponding to a fragment of myosin heavy chain, non-muscle type A), vinculin, a tropomyosin isoform, and the macrophage capping protein were increased. A shift in caldesmon isoforms was also detected. These results demonstrate an association between DN and the constitutive expression of cytoskeleton proteins in cultured skin fibroblasts from T1DM with DN, which may retain pathophysiologycal implications. 相似文献