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81.
Thiago Luís Lopes Siqueira Cristina Dutra de Aguiar Ciferri Valéria Cesário Times Ricardo Rodrigues Ciferri 《GeoInformatica》2014,18(2):313-356
Although many real world phenomena are vague and characterized by having uncertain location or vague shape, existing spatial data warehouse models do not support spatial vagueness and then cannot properly represent these phenomena. In this paper, we propose the VSCube conceptual model to represent and manipulate shape vagueness in spatial data warehouses, allowing the analysis of business scores related to vague spatial data, and therefore improving the decision-making process. Our VSCube conceptual model is based on the cube metaphor and supports geometric shapes and the corresponding membership values, thus providing more expressiveness to represent vague spatial data. We also define vague spatial aggregation functions (e.g. vague spatial union) and vague spatial predicates to enable vague SOLAP queries (e.g. intersection range queries). Finally, we introduce the concept of vague SOLAP and its operations (e.g. drill-down and roll-up). We demonstrate the applicability of our model by describing an application concerning pest control in agriculture and by discussing the reuse of existing models in the VSCube conceptual model. 相似文献
82.
Synthesis of Crosslinked Copolymers based on Acrylonitrile Containing Carboxyl and Amidrazone Groups
Erika Carneiro Riqueza Alcino Palermo de Aguiar Mônica R.M.P. Aguiar Luiz C. de Santa Maria 《Polymer Bulletin》2005,55(1-2):31-40
Summary Chelating networks based on modified chemically acrylonitrile with hydrazine at alkaline solution were synthesized. The resin beads with different porosities were obtained by aqueous suspension copolymerization of acrylonitrile (AN) and divinylbenzene (DVB). The unmodified and modified resins were characterized by bulk density, surface area, average pore diameter, elemental analysis (CHN), FTIR, 13C CP/MAS NMR and scanning electronic microscopy. Elemental analyses were used to observe the increasing of nitrogen and oxygen contents due to chemical modification. Spectroscopic techniques (FTIR and 13C CP/MAS NMR) were employed to study the structural changes provoked by the modification with hydrazine. The contents of carboxyl and amidrazone group into the copolymer structure were dependent on the reaction conditions. 相似文献
83.
Alex Borges Vieira Rafael Barra de Almeida Jussara Marques de Almeida Sérgio Vale Aguiar Campos 《Computer Networks》2013,57(4):1019-1036
Peer-to-Peer (P2P) streaming has become a popular platform for transmitting live content. However, due to their increasing popularity, P2P live streaming systems may be the target of user opportunistic actions and malicious attacks, which may greatly reduce streaming rate or even stop it completely. In this article, we focus on a specific type of attack called content pollution, in which malicious peers tamper or forge media data, introducing fake content before uploading it to their partners in the overlay network. Specifically, we present a new decentralized reputation system, named SimplyRep, that quickly identifies and penalizes content polluters, while incurring in low overhead in terms of bandwidth consumption. We evaluate our method with both simulation and experiments in PlanetLab, comparing it against two previously proposed approaches, namely, a centralized black list and a distributed reputation system, in various scenarios. Our results indicate that SimplyRep greatly outperforms the two alternatives considered. In particular, both black list and the distributed reputation method perform poorly when polluters act jointly in a collusion attack, reaching a data retransmission overhead (triggered by polluted chunks received) of 70% and 30%, respectively, whereas the overhead experienced by SimplyRep is at most 2%. Our results also show that SimplyRep is able to quickly isolate almost all polluters under a dissimulation attack, being also somewhat robust to a whitewashing attack, although the latter remains a challenge to effective P2P streaming. 相似文献
84.
Dayse Silveira de Almeida Carmem Satie Hara Ricardo Rodrigues Ciferri Cristina Dutra de Aguiar Ciferri 《Software》2018,48(1):197-232
Reconciliation is the process of providing a consistent view of the data imported from different sources. Despite some efforts reported in the literature for providing data reconciliation solutions with asynchronous collaboration, the challenge of reconciling data when multiple users work asynchronously over local copies of the same imported data has received less attention. In this paper, we propose AcCORD, an asynchronous collaborative data reconciliation model based on data provenance. AcCORD is innovative because it supports applications in which all users are required to agree on the data values to provide a single consistent view to all of them, as well as applications that allow users to disagree on the data values to keep in their local copies but promote collaboration by sharing integration decisions. We also introduce a decision integration propagation method that keeps users from taking inconsistent decisions over data items present in several sources. Further, different policies based on data provenance are proposed for solving conflicts among multiusers' integration decisions. Our experimental analysis shows that AcCORD is efficient and effective. It performs well, and the results highlight its flexibility by generating either a single integrated view or different local views. We have also conducted interviews with end users to analyze the proposed policies and feasibility of the multiuser reconciliation. They provide insights with respect to acceptability, consistency, correctness, time‐saving, and satisfaction. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
85.
Érica Aguiar Moraes Valéria Aparecida Vieira Queiroz Robert Eugene Shaffert Neuza Maria Brunoro Costa Julia D. Nelson Sônia Machado Rocha Ribeiro Hércia Stampini Duarte Martino 《Food chemistry》2012
The in vivo protein qualities were evaluated in flours from raw sorghum grains (RF) and flours from sorghum grains subjected to heat treatment in an oven (HTF) from the hybrids BRS 305, BRS 309 and BRS 310, developed by the Brazilian Agricultural Research Corporation (Embrapa). There were no differences in feed efficiency ratios among experimental groups. Heat-treated flour from BRS 309 and BRS 310 genotypes had higher protein efficiency ratios and net protein ratio values; however, they did not differ from those of flour from raw grain of BRS 310 genotype. Effects of heat treatment were observed in the BRS 309 genotype. Heat treatment did not affect true digestibility observed for the RF and HTF of the three genotypes. Lysine was the first limiting amino acid of the three sorghum genotypes. The HTF BRS 305 showed the lowest protein digestibility-corrected amino acid score value. Heat treatment improved the protein quality of genotype BRS 309; however, no differences were observed among the other genotypes. 相似文献
86.
lida B. Hermida Diego G. Melo Julio C. Aguiar Daniel E. Lpez 《Journal of Alloys and Compounds》2000,310(1-2):91-96
The elastic modulus and the internal friction of Sn and the γ-In–Sn phase are measured with a two-component piezoelectric oscillator at 50 kHz in the temperature range from 296 to 390 K. For both materials the viscoelastic responses at strains below 10−6 are described in terms of a Debye peak characterized by an effective activation enthalpy of 54.8 and 20.4 kJ/mol, for Sn and the γ-In–Sn phase, respectively. Due to their higher damping, the dynamic mechanical responses of In and the eutectic In–Sn were measured with a three-components piezoelectric resonator between 296 and 390 K at 50 kHz. The temperature dependence of the internal friction of the eutectic can be well described in terms of a single relaxation time with an effective activation enthalpy of 38 kJ/mol. Indium is not only amplitude dependent but also exhibits thermal hysteresis. 相似文献
87.
A new laboratory kiln was developed and built to perform over a very wide range of drying conditions. For example, the dry bulb temperature can vary from 30°C to 150°C and the dew point can be adjusted between 20°C and 130°C. Obviously, with such a high level of dew point, pressures over atmospheric pressure may be induced inside the chamber. For this reason, the kiln has been designed to withstand pressure of up to 3 bars. This kiln can also perform vacuum drying.
A programmable controller allows the temperature levels to be maintained within ± 0.2°C. Because the whole kiln can be heated only through the agitated water present at the bottom of the kiln, the load temperature can be increased up to 130°C in saturated conditions, without any change of moisture content.
The kiln has various sensors attached and is capable of withstanding severe conditions (high temperature, saturated vapour and elevated pressures). At present, air and water temperatures as well as temperature at different locations within the board can be collected during the drying process. A load cell and pressure gauges are also available. The first tests performed using this equipment are presented at the end of the paper. 相似文献
A programmable controller allows the temperature levels to be maintained within ± 0.2°C. Because the whole kiln can be heated only through the agitated water present at the bottom of the kiln, the load temperature can be increased up to 130°C in saturated conditions, without any change of moisture content.
The kiln has various sensors attached and is capable of withstanding severe conditions (high temperature, saturated vapour and elevated pressures). At present, air and water temperatures as well as temperature at different locations within the board can be collected during the drying process. A load cell and pressure gauges are also available. The first tests performed using this equipment are presented at the end of the paper. 相似文献
88.
Mauro Vitor Mendlowicz Evandro Silva Freire Coutinho Jerson Laks Leonardo Franklin Fontenelle Alexandre Martins Valen?a William Berger Ivan Figueira Gl��ucia Azambuja de Aguiar 《Scientometrics》2011,86(1):27-37
The aim of this study was to investigate the existence of a ??gender gap?? in the authorship of the four most important peer-reviewed psychiatric journals in Brazil and to quantify its magnitude. In addition, we examined the patterns of change in this gap during the period extending from 2001 to 2008 and variations according to the total number of authors, the type of article (original vs. non-original studies), and the journals themselves. A total of 1,036 articles were analyzed. We found that the proportion of female overall participation has increased from 2001 to 2008. Nevertheless, the incremental rate was accounted mostly by the growth of the participation in non-original articles. While the average annual increment for original articles was virtually null (.01%), for the non-original articles the corresponding figure was 3.7%. We also found that the chance of a woman being first author was about three times greater in original papers as compared to non-original ones at the beginning of the study period; this differential declined by 11% per year during this period. A different pattern emerged from the analysis of female last authorship. Year of publication and type of study were still associated with the chance of a woman being the last author but without interaction. Further, the journals themselves were found to be related with female last authorship: the chance of a woman being the last author in an article published in the Revista Brasileira de Psiquiatria was significantly smaller than in the other three journals. Our findings indicate clearly that some progress in being achieved in eliminating the gender gap also in field of Psychiatry and highlight the need for further research in this area. 相似文献
89.
Normal erythrocytes are under physiological conditions characterized by low cation and high anion conductance. However, in the case of sickle cell anemia the erythrocytes contain a modified haemoglobin, HbS, which under low oxygen tension gives rise to sickling. This condition is preceded by an increase in cation conductance, especially due to the Ca2+-activated K+-channels, leading to net-efflux of KCI and thereby decreased cellular volume, which is part of the pathological condition.A possible symptomatic treatment could be application of conductance blockers, targeting the Ca2+-activated K+-channel or the anion conductance in order to minimize the passive transport of ions and solvent. It has been argued, that due to the high anion conductance, solute loss depended at moderately increased cation conductances on the cation only. Consequently the Ca2+-activated K+-conductance should be the target for attempts to modify solute loss.It is shown that: knowledge of mean conductances (time averages) for pathways showing fluctuations are insufficient to predict the quantitative effect of conductance inhibitors, since inhibition is strongly dependent on the kinetics of the mechanisms mediating the translocation and a block of the high conductance anion pathway can be as effective as inhibition of the Ca+-activated K+-conductance with regard to net salt loss. 相似文献
90.