Improved background modeling for real-time spatio-temporal non-parametric moving object detection strategies

Answering to the growing demand of machine vision applications for the latest generation of electronic devices endowed with camera platforms, several moving object detection strategies have been proposed in recent years. Among them, spatio-temporal based non-parametric methods have recently drawn the attention of many researchers. These methods, by combining a background model and a foreground model, achieve high-quality detections in sequences recorded with non-completely static cameras and in scenarios containing complex backgrounds. However, since they have very high memory and computational associated costs, they apply some simplifications in the background modeling process, therefore decreasing the quality of the modeling.     

Forest biomass estimation through NDVI composites. The role of remotely sensed data to assess Spanish forests as carbon sinks

The present study is focused on the capabilities of remote sensing data and techniques to help in the monitoring of forest ecosystems as carbon sinks. It will attempt to find statistical relationships between satellite‐derived NDVI (Normalized Difference Vegetation Index) data from SPOT‐VEGETATION and NOAA‐AVHRR and field measurements from the Spanish National Forest Inventory on the geographical basis of provinces. Statistically significant relationships were obtained when correlating the aforementioned datasets. These relationships were then used to predict forest biomass at a national level, in order to obtain updated forest information between consecutive National Forest Inventories.     

MERIS‐FR potential for land use–land cover mapping in Spain

Abstract

Since 1984, national and international agencies have sought to improve their ability to forecast famine in sub-Saharan Africa. A number of early warning systems have been implemented for this purpose that monitor physical and social variables that may indicate the likelihood and magnitude of famine. Several famine early warning systems use satellite remote sensing data to supplement ground-based observations. These systems have demonstrated the advantages in timeliness and consistency of remote sensing data. Although user needs have not been clearly defined, experience gained in the operation of early warning systems and the results of related research suggest that: (a) at the continental scale AVHRR GAC data offer many advantages over traditional, ground data sources;

(b) quantitative crop yield estimates might be improved through consideration of both photosynthetic activity of the vegetation and length of growing season;

(c)qualitative comparisons of crop years have provided useful inputs to current early warning needs; and (d) stratification of the region into coherent geographical areas would improve all estimates:     

Studying the change in fAPAR after forest fires in Siberia using MODIS

Disturbance events such as fire have major effects on forest dynamics, succession and the carbon cycle in the boreal biome. This paper focuses on establishing whether characteristic spatio‐temporal patterns of the fraction of Absorbed Photosynthetically Active Radiation (fAPAR) occur in the initial two years after a fire event in Siberian boreal forests. Time‐series of MODIS fAPAR were used to study post‐fire dynamics during the year of the fire and the following two years. Three forest types (evergreen needle‐leaf, deciduous needle‐leaf and deciduous broadleaf) grouped into three latitudinal regions, ranging from 51° N to 65° N, were studied by analysing a sample of 14 burned areas. For each of the burned areas an adjacent unburned control plot was selected with the aim of separating inter‐annual variations caused by climate from changes in fAPAR behaviour due to a burn. The results suggest that (i) the forest types exhibit characteristic fAPAR change trajectories shortly after the fire, (ii) the differences in the fAPAR trajectories are related to the forest type, (iii) fAPAR changes are not significantly different among the latitudinal regions, and (iv) the limited temporal variability observed among the 3 years of observations indicates that fAPAR varies very little in the initial years after a fire event.     

Influence of oxygen on the sputtering of aluminum oxide for the surface passivation of crystalline silicon

While sputtering has been shown to be capable of depositing aluminum oxide suitable for surface passivation, the mechanisms for this are yet to be firmly established and its potential realized. In this paper, we investigate the relationships between the oxygen in the sputtering process to the resulting composition of the deposited film and the surface passivation obtained. We find that surface passivation is not strongly dependent on the bulk composition of the film. Instead the results indicate that the interfacial silicon oxide layer that forms after annealing between the aluminum oxide film and the silicon is a much more important factor; it is this combined structure of aluminum oxide, silicon oxide and silicon that is crucial for obtaining negative charges and excellent surface passivation.     

Harmonic reduction in adjustable-speed synchronous motors

Adjustable-speed synchronous motors (ASSM) are very popular in high-power high-speed applications. The Chilean mining industry uses them in milling operations in ranges of several thousands hp. Although a high pulse number for the inverter would be beneficial, it never goes beyond 12, due to complicated connections. Thus, a distorted harmonic-rich current feeds the synchronous motor, increasing the inverter commutation angle and causing additional rotor-heating and pulsating electric torque. Harmonic suppression by filters is not viable due to the variable frequency nature of the motor. In this paper, a new design for the inverter, without complicated circuitry, is proposed, so that it works with 36 pulses and then the motor is fed with a highly sinusoidal current. Also, the same technique is applied to the rectifier end, so that an effective harmonic reduction is carried out at both ends of the system, i.e., the motor as well as the AC supply system. A 20 kVA laboratory development drive system has been built and experimental waveforms for the conventional (12-pulse) and proposed (36-pulse) configurations are included     

A satellite remote-sensing multi-index approach to discriminate pelagic Sargassum in the waters of the Yucatan Peninsula,Mexico

Recently, the need for quantitative information on the spatiotemporal distribution of floating macroalgae, particularly the two species of genus Sargassum, has grown because of blooms of these species in the Gulf of Mexico and Caribbean Sea. Remote sensing is one of the most frequently used tools to assess pelagic Sargassum distribution. The purpose of this study was to implement a methodological approach to detect floating algae in an efficient and replicable manner at a moderate cost. We analyzed Landsat 8 imagery, from which we calculated four vegetation indices and one floating-algae index to implement a supervised classification, together with the bands 2 and 5, using the Random Forest algorithm. The analysis was performed monthly from 2014 to 2015 for the northeastern Yucatan Peninsula, Mexico, with a total of 91 analyzed images. The quantitative performance metrics of the classifier (overall, Kappa and Tau) were greater than 80%, whereas bands 2 and 5 as well as the atmospherically resistant vegetation index made the greatest contributions to the classifications. During summer 2015, more than 4,000 ha of Sargassum coverage per image were observed, which was substantially greater than that over the rest of the period. This approach constitutes a transferable alternative for the systematic detection of Sargassum, which enables a quantitative semi-automated time series comparison.     

The Therapeutic Effect of Intranasal Administration of Dexamethasone in Neuroinflammation Induced by Experimental Pulmonary Tuberculosis

Tuberculosis (TB) is an important infectious disease and a public health problem. The organs most frequently affected by TB are the lungs; despite this, it has been reported that TB patients suffer from depression and anxiety, which have been attributed to social factors. In previous experimental work, we observed that the extensive pulmonary inflammation characteristic of TB with high cytokine production induces neuroinflammation, neuronal death and behavioral abnormalities in the absence of brain infection. The objective of the present work was to reduce this neuroinflammation and avoid the psycho-affective disorders showed during pulmonary TB. Glucocorticoids (GCs) are the first-line treatment for neuroinflammation; however, their systemic administration generates various side effects, mostly aggravating pulmonary TB due to immunosuppression of cellular immunity. Intranasal administration is a route that allows drugs to be released directly in the brain through the olfactory nerve, reducing their doses and side effects. In the present work, dexamethasone’s (DEX) intranasal administration was evaluated in TB BALB /c mice comparing three different doses (0.05, 0.25 and 2.5 mg/kg BW) on lung disease evolution, neuroinflammation and behavioral alterations. Low doses of dexamethasone significantly decreased neuroinflammation, improving behavioral status without aggravating lung disease.     

Natural convection at an indoor glazing surface with different window blinds

In the present study, an empirical model to determinate the convective heat loss, at an indoor glazing surface, is proposed. This model allows calculating the convective heat transfer coefficient and the air flow rate entering to the window cavity formed between the glazing surface and the protection device. The window blind is first studied experimentally by using a rigid paper, which is installed at four different distances from the window frame. This configuration is used as reference to determinate a global model, which is mainly composed of two correlations: one for the Nusselt number and other one for the air mass flow rate incoming to the window cavity. Then, more realistic configurations are tested: single curtains, double curtains, PVC blinds, wood blinds, Venetian blinds or polyester blinds. In general, heat transfer coefficients for these configurations are equal or higher than that obtained with a free plate. Several correlations are proposed for each configuration.