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This paper proposes the Set-Membership sign-NLMS (SM-sign-NLMS) adaptive filter, which combines the ability for data censoring (offered by Set-Membership schemes) with robustness against impulsive noise (provided by signed schemes). The algorithm can present a much lower steady-state probability of update than the standard SM-NLMS algorithm when impulsive noise is present in the system. It is derived from a local deterministic optimization problem modulated by a minimum disturbance cost function combined with a bounded error criterion. Several stochastic models are proposed in order to extract insights and a time-variant step size extension of the algorithm. The first of them, based on energy conservation arguments, leads to a fixed-point analytic equation whose solution predicts the asymptotic performance of the algorithm. Further, a transient analysis based on a statistical decoupling of the radial and (discrete) angular distributions of the input vector is derived. Based on such an analysis, an efficient time-variant step-size version of the algorithm is proposed. Additionally, such an analysis is also utilized to obtain a fixed-point formula whose solution describes the asymptotic performance when the unknown plant that the filter intends to match varies according to a first-order Markovian model. Lastly, a novel stochastic model is advanced for the description of the algorithm learning behavior under a deficient-length scenario for a white input signal, which provides some insights about the asymptotic performance of the algorithm. The findings are confirmed by extensive simulations.

In applications where large-order filters are needed, the computational load of adaptive filtering algorithms can become prohibitively expensive. In this paper, a comprehensive analysis of a selective partial-update least mean squares, named SPU-LMS-M-min, is developed. By employing the partial-update strategy for a non-normalized adaptive scheme, the designer can choose an appropriate number of update blocks considering a trade-off between convergence rate and computational complexity, which can result in a more than 40% reduction in the number of multiplications in some configurations compared to the traditional LMS algorithm. Based on the principle of minimum distortion, a selection criterion is proposed that is based on the input signal’s blocks with the lowest energy, whereas typical Selective Partial Update (SPU) algorithms use a selection criterion based on blocks with highest energy. Stochastic models are developed for the mean weights and mean and mean squared behaviour of the proposed algorithm, which are further extended to accommodate scenarios involving time-varying dynamics and suboptimal filter lengths. Simulation results show that the theoretical predictions are in good agreement with the experimental outcomes. Furthermore, it is demonstrated that the proposed selection criterion can be easily extended to active noise cancellation algorithms as well as algorithms utilizing variable filter length. This allows for the reduction of computational costs for these algorithms without compromising their asymptotic performance.

Abstract In this study, we investigated the effects of the Payment for Ecosystem Services (PES) in an agrisystem located in the Brazilian Midwest. This PES benefits the owners of rural properties that encompass springs that feed the Abóbora River microbasin which supplies water for consumption in the city of Rio Verde, Goiás. We evaluated the percentage of native vegetation cover around the springs of the watercourses and also estimated its change over time (2005, 2011 and 2017). The vegetation cover of the Areas of Permanent Preservation (APP) increased by 2.24% on average, seven years after the implantation of the PES. There was little difference in the change of vegetation cover maintained over the study years (2005, 2011, and 2017), however, the vegetation cover increased for 17 springs, decreased for 11 springs, and was completely degraded for other two. To improve the performance of this PES, we recommend (1) expanding the program to include the APPs surrounding the springs, together with the legal reserves of each property, (2) implementing measures to ensure that properties are environmentally adequate, (3) including the properties in the Brazilian Rural Environment Register (CAR), and (4) obtaining environmental licensing for the activities undertaken within the Abóbora River basin.

THE USE OF FREE SOFTWARES IN PRACTICAL CLASS ABOUT THE MOLECULAR FILTERS OF ORAL BIOAVAILABILITY OF DRUGS. The study of the physical chemical properties to predict the oral bioavailability of drugs is a widely tool used by researches on the Pharmaceutical and Medicinal Chemistry field. Even though it is a deeply studied subject, it is a complex task to teach to pharmacy students. Lipinski stablished that molecular weight, lipophilicity, hydrogen bond donors and acceptors are of great importance for oral bioavailability. In addition, Veber and Lovering added other properties, such as number of rotatable bonds, fraction of sp3 hybridized carbon and polar surface area that amplified the Lipinski Rule of 5. In this sense, the access to chemical databases and the comprehension of this information is an important task to undergraduate and graduate students. Thus, this work aims a new teaching methodology that values the critical interpretation of data and that favors the students comprehension beyond stablished rules.

ABSTRACT Acoustic communication plays an important role in the social behavior of anurans. Acoustic signals, which can be used in different contexts such as mate attraction and territory defense, may mediate social interactions among individuals. Herein, we used playback experiments to test whether males of Hypsiboas goianus (Lutz, 1968) change their vocal behavior in response to conspecific advertisement calls. Specifically, we used different field playback experiments in which we modified the time interval between advertisement calls to simulate males with distinct states of motivation (Sequence A and B). We did not observe differences in the acoustic response of males of H. goianus between the two types of field playback experiments. On the other hand, we observed that H. goianus males reduce the dominant frequency of the advertisement call and increase the rate of aggressive calls in response to a conspecific competitor. Our results suggest that the acoustic plasticity observed in males of H. goianus represents an aggressive response that allows repelling conspecific individuals.