113 research outputs found
A Configurable Sensor Network Applied to Ambient Assisted Living
The rising older people population has increased the interest in Ambient Assisted Living systems. This article presents a system for monitoring the disabled or older persons developed from an existing surveillance system. The modularity and adaptability characteristics of the system allow an easy adaptation for a different purpose. The proposed system uses a network of sensors capable of motion detection that includes fall warning, identification of persons and a configurable control system which allows its use in different scenarios
VIGICOP: autonomous surveillance robots with Sodar detection and autonomous navigator
The main goal of the project described in this paper
is to create a security system using autonomous surveillance
robots that use SODAR-like detection system sensors,
working with acoustic signals in air environment and
navigation base on Geographic Information System and
Markov's models. The surveillance system based on SONAR
provides great information from the environment, even lets you
see behind objects (rebounds effects) whose manipulation
offers a great added value to surveillance The guide system
will implement in one hand a local navigation module directed
to avoid obstacles based on classical techniques and using
the new SODAR sensor. On the other hand a global
navigation module will be implemented using preset
trajectories and gradient techniques and an auto-location
system. One of the greatest challenges obtained is the
definition of the VIGICOPVar variable that defines, depending
on the environment and safety parameters, the probability of
intrusion. Surveillance experts of GRUPO NORTE
(multinational company with security expertise of more than 38
years) have worked In the definition and validation of the
model. The monitoring robots will be controlled in a centralized
way from an alarm center from where you can manage all
information relating to intrusion detected. VIGICOP is the low
cost surveillance robot which provides new/full information
interactive surveillance informatio
Characterization of a virtual array based on MEMS microphones for the analysis of acoustic sources
Optimization of a Biometric System Based on Acoustic Images
On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced
Cuantificación de sesquiterpenlactonas procedentes de las hojas de Calea urticifolia (Asteraceae) durante el año 2012
El presente estudio tuvo como objetivo principal la cuantificaciĂłn de sesquiterpenlactonas presentes en los extractos cloro fĂłrmicos secos de hojas de Calea urticifolia “Juanislama”, recolectadas bimensualmente durante el año 2012. Los metabolitos secundarios se extrajeron por medio del mĂ©todo Soxhlet usando cloroformo como solvente; se llevĂł a cabo la identificaciĂłn de los metabolitos secundarios por cromatografĂa en capa fina con reactivo de Baljet y espectroscopĂa UV utilizando marcadores analĂticos. La cuantificaciĂłn se realizĂł por espectroscopĂa visible usando Juanislamina como marcador analĂtico, encontrándose que el porcentaje de sesquiterpenlactonas totales expresadas como Juanislamina en el extracto clorofĂłrmico seco vario entre 39.58-90.02%, observándose el periodo del 02-02 al 15-04, 18-07 al 31-07 y 30-08 al 17-09 como los mejores, destacándose la recolecta del 15-02 con 90.02%; con respecto al porcentaje de sesquiterpenlactonas totales en el material vegetal seco, este vario entre 2.84-8.06%, observándose los periodos del 15-03 al 15-04 y 30-08 al 17-09 como los mejores, destacándose la recolecta del 30-03 con 8.06%.Quantification of sesquiterpene lactones present in dried leaves of Calea unticifolia “Juanislama” was systematically carried out for the whole year 2012. Leaves samples were recollected bimonthly, and the sesquiterpene lactones were extracted utilizing the Soxhlet method with chloroform as solvent. The identification of the secondary metabolites was performed by thin-layer chromatography using the Baljet reagent and by UV/Vis spectroscopy utilizing chemical markers. The concentration of total sesquiterpene lactones, expressed as Juanislamine, found in the dried chloroform extract ranged from 39.58 to 90.02%. It was observed that the time periods from February 2 to April 15, from July 18 to July 31, and from August 30 to September 17 displayed the best yields, being the sampling on February 15 the one that led to the highest yield at an outstanding 90.02%. Regarding the percentage of total sesquiterpene lactones in the dried vegetal material, this ranged from 2.84% to 8.06% in the study. Likewise, the best time periods for such percentage fell from March 15 to April 15, and from August 30 to September 17, distinguishing the sample taken on March 30, which yielded a maximum of 8.06% of sesquiterpene lactones in the dried material
Performance Evaluation of a Biometric System Based on Acoustic Images
An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side). Two Uniform Linear Arrays (ULA) with 15 λ/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR)/False Non-Match Rate (FNMR) parameters and the Receiver Operating Characteristic (ROC) curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications
Recommended from our members
Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
- …