Human activity recognition from object interaction in domestic scenarios

This paper presents a real time approach to the recognition of human activity based on the interaction between people and objects in domestic settings, specifically in a kitchen. Regarding the procedure, it is based on capturing partial images where the activity takes place using a colour camera, and processing the images to recognize the present objects and their location. For object description and recognition, a histogram on rg chromaticity space has been selected. The interaction with the objects is classified into four types of possible actions; (unchanged, add, remove or move). Activities are defined as recipes, where objects play the role of ingredients, tools or substitutes. Sensed objects and actions are then used to analyze in real time the probability of the human activity performed at a particular moment in a continuous activity sequence.Peer ReviewedPostprint (author's final draft

Admissible relative errors of the parcel area of a land parcel map base created as a synthesis of individual survey maps

Today the land parcel map of Uruguay is available as an updated, integrated legacy digital cadastre which planimetric accuracy is not enough to assure geometric interoperability. The creation of a brand new land parcel map is being considered with a procedure yet to be defined but in any case subject to reasonable goals in terms of geometric accuracy. In this paper we have tested a direct procedure in which each parcel is joined to its immediate neighbors until a block is formed. In Uruguay such block will grow until a road, river or similar object is found. The block is manually inserted within the road network, which has absolute coordinates. The rural survey maps (approx. 250 000) are already scanned but they need to be vectorized and edited through scaling, rotation and manual matching to its neighbors. GNSS tracks for roads and highways are available for the whole country, so we could fit the block within them in order to properly register it. The resulting geometric accuracy was evaluated in terms of the relative error in area, which has a normal distribution with a mean 0.10% and a standard deviation 3.51%, leaving 82.0% of the parcels with relative area error less than 5%. The planimetric error, crucial to assure interoperability, was 53.79 m at the 95% confidence level

Quasi-Regression Monte-Carlo Method for Semi-Linear PDEs and BSDEs

[Abstract] In this work we design a novel and efficient quasi-regression Monte Carlo algorithm in order to approximate the solution of discrete time backward stochastic differential equations (BSDEs), and we analyze the convergence of the proposed method. With the challenge of tackling problems in high dimensions we propose suitable projections of the solution and efficient parallelizations of the algorithm taking advantage of powerful many core processors such as graphics processing units (GPUs)

A Two-Dimensional Multi-Species Model for Different Listeria Monocytogenes Biofilm Structures and Its Numerical Simulation

[Abstract] In this work we propose a two-dimensional multi-species model to describe the dynamics of biofilms formed by the pathogenic bacteria Listeria monocytogenes. Different Listeria monocytogenes strains produce biofilms with different structures, namely flat, honeycomb and clustered. Previous works showed that glucose impaired uptake and the appearance of damaged or dead cells are critical mechanisms underlying Listeria monocytogenes biofilm dynamics. Here we explicitly propose an extension of the two-dimensional multi-species model proposed by Alpkist and Klapper to account for those mechanisms. The result is a continuous two-dimensional multi-species model with non-linear detachment and mass action nutrient consumption. Moreover, we also propose a set of efficient numerical methods to solve the coupled model and we have developed their computer implementation from scratch in C/C++. Mainly based on finite differences schemes, these numerical techniques include Crank-Nicolson schemes for time discretization, Gibou’s ghost node techniques and level set methods to cope with the free boundary associated to the determination of the time-dependent biofilm domain. To finish with, we compare our simulation results with the dynamics of real biofilms as observed in the laboratory. More precisely, by using model parameters calibrated to experiments, the numerical results clearly illustrate the performance of the proposed model and the numerical methods to reproduce the real dynamics of flat, clustered and honeycomb structures shown by different Listeria monocytogenes strains.ALN and CV acknowledge the funding by MINECO from Spanish Government (Grant MTM2016-76497-R) and by Xunta de Galicia (Grants GRC2014/044 and ED431C2018/033). ALN acknowledges FPU fellowship (FPU13/02191) from the Spanish Government program MECD-FPU. CV and ALN as members of CITIC also akcnowledge the grant ED431G 2019/01, funded by Consellería de Educación, Universidade e Formación Profesional of Xunta de Galicia through FEDER funds with 80%, from FEDER Galicia 2014-2020 Program and 20% from Secretaría Xeral de Universidades. EBC acknowledges funding from Contrato Programa and grant Ref. IN607B 2017/02 from Xunta de Galicia. All grants include FEDER fundsXunta de Galicia; GRC2014/044Xunta de Galicia; ED431C2018/033Xunta de Galicia; ED431G 2019/01Xunta de Galicia; IN607B 2017/0

Random Generation of Arbitrary Waveforms for Emulating Three-Phase Systems

This paper describes an apparatus for generating a signal representative of steady-state and transient disturbances in three-phase waveforms of an ac electrical system as described in IEEE Std 1159-09. It can be configured as a synthesizer of randomly distorted signals for different applications: for testing the effects of disturbed grid on equipment and to generate patterns of electrical disturbances for the training of artificial neural networks, which are used for measuring power quality tasks. For the first purpose, voltage and current amplifiers are added in the output stage, which allows the generation of disturbed signals at grid level.Comisión Interministerial de Ciencia y Tecnología DPI2006-15467-C02-01Comisión Interministerial de Ciencia y Tecnología DPI2006-15467-C02-0

Reliability evaluation of III-V concentrator solar cells

Concentrator solar cells have been proposed as an interesting way of reducing the cost of photovoltaic electricity. However, in order to compete with conventional solar modules it is necessary not only to reduce costs but also to evaluate and increase the present reliability. Concentrator solar cells work at higher temperature, solar radiation and current stress than conventional solar cells and a carefully reliability analysis is needed. In this paper a reliability analysis procedure, that is being developed, is presented

Reliability Improvement in III-V Concentrator Solar Cells by Means of Perimeter Protection

This paper presents the evolution in the strategy to assess the reliability of III-V solar cells and a new thermal ageing test carried out over GaAs single junction solar cells at three different temperatures (130, 150 and 170° C). The perimeter of the solar cells has been protected with silicone, which seems to be an effective way of enhancing the reliability of the solar cells. A preliminary analysis of the results indicates a mean time to failure (MTTF) one order of magnitude larger than the one obtained in a previous thermal test with the perimeter uncoated