Object Matching in Distributed Video Surveillance Systems by LDA-Based Appearance Descriptors

Establishing correspondences among object instances is still challenging in multi-camera surveillance systems, especially when the cameras’ fields of view are non-overlapping. Spatiotemporal constraints can help in solving the correspondence problem but still leave a wide margin of uncertainty. One way to reduce this uncertainty is to use appearance information about the moving objects in the site. In this paper we present the preliminary results of a new method that can capture salient appearance characteristics at each camera node in the network. A Latent Dirichlet Allocation (LDA) model is created and maintained at each node in the camera network. Each object is encoded in terms of the LDA bag-of-words model for appearance. The encoded appearance is then used to establish probable matching across cameras. Preliminary experiments are conducted on a dataset of 20 individuals and comparison against Madden’s I-MCHR is reported

Disc Clearing of Young Stellar Objects: Evidence for Fast Inside-out Dispersal

The time-scale over which and the modality by which young stellar objects (YSOs) disperse their circumstellar discs dramatically influences the eventual formation and evolution of planetary systems. By means of extensive radiative transfer (RT) modelling, we have developed a new set of diagnostic diagrams in the infrared colour-colour plane (K-[24] vs. K-[8]), to aid with the classification of the evolutionary stage of YSOs from photometric observations. Our diagrams allow the differentiation of sources with unevolved (primordial) discs from those evolving according to different clearing scenarios (e.g. homologous depletion vs. inside-out dispersal), as well as from sources that have already lost their disc. Classification of over 1500 sources in 15 nearby star-forming regions reveals that approximately 39 % of the sources lie in the primordial disc region, whereas between 31 % and 32 % disperse from the inside-out and up to 22 % of the sources have already lost their disc. Less than 2 % of the objects in our sample lie in the homogeneous draining regime. Time-scales for the transition phase are estimated to be typically a few 10^5 years independent of stellar mass. Therefore, regardless of spectral type, we conclude that currently available infrared photometric surveys point to fast (of order 10 % of the global disc lifetime) inside-out clearing as the preferred mode of disc dispersal.Comment: 31 pages, 21 figures, 6 tables, accepted for publication in MNRA

High Resolution 4.7 um Keck/NIRSPEC Spectra of Protostars. I: Ices and Infalling Gas in the Disk of L1489 IRS

We explore the infrared M band (4.7 um) spectrum of the class I protostar L1489 IRS in the Taurus Molecular Cloud. This is the highest resolution wide coverage spectrum at this wavelength of a low mass protostar observed to date (R=25,000; Dv=12 km/s). Many narrow absorption lines of gas phase 12CO, 13CO, and C18O are detected, as well as a prominent band of solid 12CO. The gas phase 12CO lines have red shifted absorption wings (up to 100 km/s), likely originating from warm disk material falling toward the central object. The isotopes and the 12CO line wings are successfully fitted with a contracting disk model of this evolutionary transitional object (Hogerheijde 2001). This shows that the inward motions seen in millimeter wave emission lines continue to within ~0.1 AU from the star. The colder parts of the disk are traced by the prominent CO ice band. The band profile results from CO in 'polar' ices (CO mixed with H2O), and CO in 'apolar' ices. At the high spectral resolution, the 'apolar' component is, for the first time, resolved into two distinct components, likely due to pure CO and CO mixed with CO2, O2 and/or N2. The ices have probably experienced thermal processing in the upper disk layer traced by our pencil absorption beam: much of the volatile 'apolar' ices has evaporated and the depletion factor of CO onto grains is remarkably low (~7%). This study shows that high spectral resolution 4.7 um observations provide important and unique information on the dynamics and structure of protostellar disks and the evolution of ices in these disks.Comment: 11 pages, 6 figures Scheduled to appear in ApJ 568 n2, 1 April 200

Calagem e fósforo para a formação de mudas de biribazeiro.

O objetivo deste trabalho foi avaliar o efeito da aplicação de doses de calcário e de fósforo na nutrição, no crescimento e na produção de matéria seca de mudas de biribá

Up scaling guava water balance in the Petrolina-Juazeiro growing area, Northeast Brazil.

Made available in DSpace on 2017-06-17T00:36:21Z (GMT). No. of bitstreams: 1 Heriberto12012.pdf: 894482 bytes, checksum: 08c140b450852815e3c3183f5056e2af (MD5) Previous issue date: 2012-10-222012Edição do Proceedings of the III International Symposium on Guava and other Myrtaceae, Petrolina, sept. 2012

Delimitation of guava water productivity in the Brazilian Northeast.

The intensification of agricultural crops in the Brazilian northeast results in a change of natural vegetation, making the quantification and evaluation of the additional water use important. Applications of a Geographic Information System (GIS) are presented in this paper to estimate the guava water productivity (GWP) on a large scale. Long-term weather data were used together with regression models involving crop coefficient (Kc), reference evapotranspiration (ET0) and accumulated degree days (DDac) to quantify the guava water requirements (GWR) in the Brazilian Northeast producer states, considering an average growing season of six months and the cultivar ‘Paluma’ as a reference. By coupling GWR data with total precipitation for a growing season, it was possible to quantify the guava water deficit (GWD) giving an estimate about irrigation needs. Considering the whole region, the variation of the averaged GWD values ranged from 50 mm for pruning dates in January to 520 mm, with pruning done in May. Associating the average GWR values with yield data for 2010 from the Brazilian Geographical and Statistical Institute (IBGE), the average biophysical and economic values of GWP were estimated for each guava producer state. The biophysical values were between 0.86 and 4.95 kg m-3 for pruning dates in July and January in Rio Grande do Norte and Pernambuco states, respectively, while the economic ones ranged from 0.40 to 3.18 R$ m-3 for the same pruning periods, however, with the lowest averaged value being for Paraíba state. The states of Pernambuco, Bahia and Piauí presented the largest biophysical and economic GWP values. The spatially presented analyses can subsidize programs for the expansion of rainfed guava crop as well as water allocation criteria under irrigation conditions, aiming at improvements for water resource use.Edição do Proceedings of the III International Symposium on Guava and other Myrtaceae, Petrolina, sept. 2012