Efren Gonzalez-Ramirez

A LED-based smart illumination system for studying plant growth

A smart illumination system for greenhouses and growing rooms capable of controlling the quantity and quality of light emitted by a number of LEDs is described. The system uses lamps containing blue and red LEDs programmed to emit various spectra at sixteen different frequencies and ten different pulse widths. The performance of the system is evaluated by determining the effect of pulsed light emission at different frequencies with a pulse width of 50% on tomato plants (Lycopersicon esculentum). The results show that low frequencies (0.1, 1, 10 Hz) have higher quantum efficiency in photosystem II compared to higher frequencies (50 and 100 kHz) and continuous light. They also show that the electron transport rate decreases when the frequency of pulses increases.

Tank Model Coupled with an Artificial Neural Network

Tank models have been used in many Asian countries for flood forecasting, reservoir operation, river basin modeling, etc. In this work a tank model is coupled with an ANN (Artificial Neural Network) for modeling a rainfall-runoff process. The ANN controls six of the tank model parameters to adjust them along time in order to improve efficiency. The data used in the simulations were collected from the Brue catchment in the South West of England. It should be pointed out that the raingauge network in this study is extremely dense (for research purposes) and does not represent the usual raingauge density in operational flood forecasting systems.

Abel transform inversion using Kalman filter

Refractive index, temperature, pressure, velocity and many other physical magnitudes of phase objects in the refraction less limit are of great interest in engineering and science. Optical tomography is a technique used to estimate these magnitudes. For axially symmetrical phase objects the tomographic reconstruction can be carried out from just one projection when using Abel transform. However, for noisy projections the reconstruction shows low quality. This quality can be improved when using the Kalman filter to compute the inverse Abel Transform. In this paper a tomographic reconstruction method for syntectic axially symmetrical phase objects using Kalman filter is presented.

Comparative analysis of directional filtering techniques in fringe patterns

We present a comparison of some methodologies that exist for directional filtering of fringe patterns. An important task in fringe image processing is the noise filtering. The implementation of linear filters is not always a proper procedure in the presence of high density fringes because the signal and noise are mixed in Fourier space. The objective of this report is to carry out a comparison of existing procedures to determine which of them provides a better image estimation. The techniques considered in this work are: Regularized Filters (RQCF), Oriented spatial filter masks (OSFM), Second-Order Oriented partial differential equations (SOPDE) and Directional filters (DF). To compare these techniques, we analyze their performance for different noise levels, using synthetic fringe images.

Evolutionary Algorithms in Modelling of Biosystems

Globally there is a land area of 13000 million ha, of which the area used for agricultural production is 1500 million ha (Naciones Unidas sobre el Desarrollo de los Recursos Hidricos en el mundo [NUDRHM], 2006), that is 12% of the total surface. Because the productivity of the agricultural sector is reduced, in general, the intensive production in controlled environments is an alternative to increase productivity in the aforementioned sector. For this reason, the use of greenhouses for agricultural production has increased in recent years. In the world, currently some 265,000 hectares are cultivated in greenhouses. Asia, with more than 138,000, represents at this moments the leading world power in intensive production under plastic cover. In the second place, with 95,000 ha, the Mediterranean basin is placed. Northern Europe (16,000 ha) and the American Continent (15,600 ha) share the rest. Holland remains the maximum exponent in agriculture under high-tech cover, especially so that which refers to crystal greenhouses. The crop inside greenhouse allows to obtain productions of better quality and higher yields, at any time of the year, while it permits extending the cycle of farming, enabling production in the most difficult times of the year and getting better prices. Due to the benefits that provide crops inside greenhouse, crops should have a controlled microclimate using different systems to regulate environmental conditions, limiting the excesses and filling shortcomings in terms of crop needs, in order to take place in every moment the optimal conditions of different stages of plant development. In addition to the advantages that production has in controlled environments it is important to reduce production costs, such as heating costs, irrigation and fertilization. To achieve this it is necessary to have a system that controls the environment inside the greenhouse that allows improving production and crop quality, product quality, time of the production process and improving production costs. Moreover, the system should allow the farmer to have sufficient information about requirements and changes observed over time in crop development. These control systems are based on mathematical models that describe the behavior of variables, such as air temperature, the concentration of carbon dioxide (CO2) and absolute humidity. Therefore, to improve the productivity of the crop under greenhouse it is necessary to study the process