A Real-Time FPGA-Based Metaheuristic Processor to Efficiently Simulate a New Variant of the PSO Algorithm.

Nowadays, high-performance audio communication devices demand superior audio quality. To improve the audio quality, several authors have developed acoustic echo cancellers based on particle swarm optimization algorithms (PSO). However, its performance is reduced significantly since the PSO algorithm suffers from premature convergence. To overcome this issue, we propose a new variant of the PSO algorithm based on the Markovian switching technique. Furthermore, the proposed algorithm has a mechanism to dynamically adjust the population size over the filtering process. In this way, the proposed algorithm exhibits great performance by reducing its computational cost significantly. To adequately implement the proposed algorithm in a Stratix IV GX EP4SGX530 FPGA, we present for the first time, the development of a parallel metaheuristic processor, in which each processing core simulates the different number of particles by using the time-multiplexing technique. In this way, the variation of the size of the population can be effective. Therefore, the properties of the proposed algorithm along with the proposed parallel hardware architecture potentially allow the development of high-performance acoustic echo canceller (AEC) systems.

A biologically inspired spiking neural P system in selective visual attention for efficient feature extraction from human motion.

Nowadays, human action recognition has become an essential task in health care and other fields. During the last decade, several authors have developed algorithms for human activity detection and recognition by exploiting at the maximum the high-performance computing devices to improve the quality and efficiency of their results. However, in real-time and practical human action recognition applications, the simulation of these algorithms exceed the capacity of current computer systems by considering several factors, such as camera movement, complex scene and occlusion. One potential solution to decrease the computational complexity in the human action detection and recognition can be found in the nature of the human visual perception. Specifically, this process is called selective visual attention. Inspired by this neural phenomena, we propose for the first time a spiking neural P system for efficient feature extraction from human motion. Specifically, we propose this neural structure to carry out a pre-processing stage since many studies have revealed that an analysis of visual information of the human brain proceeds in a sequence of operations, in which each one is applied to a specific location or locations. In this way, this specialized processing have allowed to focus the recognition of the objects in a simpler manner. To create a compact and high speed spiking neural P system, we use their cutting-edge variants, such as rules on the synapses, communication on request and astrocyte-like control. Our results have demonstrated that the use of the proposed neural P system increases significantly the performance of low-computational complexity neural classifiers up to more 97% in the human action recognition.

Confidentiality in medical images through a genetic-based steganography algorithm in artificial intelligence.

Nowadays, image steganography has an important role in hiding information in advanced applications, such as medical image communication, confidential communication and secret data storing, protection of data alteration, access control system for digital content distribution and media database systems. In these applications, one of the most important aspects is to hide information in a cover image whithout suffering any alteration. Currently, all existing approaches used to hide a secret message in a cover image produce some level of distortion in this image. Although these levels of distortion present acceptable PSNR values, this causes minimal visual degradation that can be detected by steganalysis techniques. In this work, we propose a steganographic method based on a genetic algorithm to improve the PSNR level reduction. To achieve this aim, the proposed algorithm requires a private key composed of two values. The first value serves as a seed to generate the random values required on the genetic algorithm, and the second value represents the sequence of bit locations of the secret medical image within the cover image. At least the seed must be shared by a secure communication channel. The results demonstrate that the proposed method exhibits higher capacity in terms of PNSR level compared with existing works.

Autonomic function and its relationship with central obesity and hemodynamic variables in obese and overweight adults.

Introduction: Introduction: central obesity is associated with an autonomic dysfunction characterized by an increase in sympathetic activity and a reduction in vagal tone, leading to a decrease in heart rate variability. Objective: we aimed to analyze the relationship between the time and frequency domains of heart rate variability with central obesity, and its hemodynamic variables in normal-weight, overweight and obese adults. Methods: a total of 65 adults were evaluated (25.4 ± 3.2 years old) and distributed in 3 groups: normal weight group (NW group), overweight group (OW group) and obese group (OB group). Heart rate variability parameters at rest and both anthropometric and hemodynamic variables were recorded. Results: the results showed a positive correlation between waist circunference and LF/HF ratio in the OW (p = 0.0008; r = 0.6607; r2 = 0.4365) and OB (p = 0.0001; r = 0.8286; r2 = 0.6866) groups. The waist-to-height ratio showed significant differences with HF in the NW, OW, and OB groups. The variables related to the parasympathetic system (SDNN, RMSSD, pNN50, HF) in the OB and OW groups showed a decrease in values when compared to the NW group. Likewise, the variable related to the sympathetic system (LF) in the OB and OW groups increased its values when compared with the NW group. The LF/HF ratio increased from the NW group to the OW and OB groups (1.6 ± 0.7; 2.5 ± 1.8 and 3.3 ± 0.7). Conclusion: overweight and obese adults present a modulation of sympathetic activity predominance at rest. This increased activity is represented by the time and frequency domains of heart rate variability, having an important correlation with waist circumference and waist-to-height ratio.

Introducción: Introducción: la obesidad central se asocia con una disfunción autonómica caracterizada por una mayor actividad simpática y reducción del tono vagal, conduciendo a una disminución de la variabilidad de la frecuencia cardíaca (VFC). Objetivo: analizar la relación entre los dominios de tiempo y frecuencia de la VFC con la obesidad central y sus variables hemodinámicas en adultos con peso normal, sobrepeso y obesidad. Metodología: participaron 65 adultos (25,4 ± 3,2 años) distribuidos en 3 grupos: peso normal (grupo NW), sobrepeso (grupo OW) y obesidad (grupo OB). Se registraron los parámetros de la VFC y las variables antropométricas y hemodinámicas. Resultados: se observó una correlación positiva entre la circunferencia de la cintura y la relación LF/HF en el grupo OW (p = 0,0008; r = 0,6607; r2 = 0,4365) y OB (p = 0,0001; r = 0,8286; r2 = 0,6866). La relacion cintura/altura mostró una diferencia significativa con la HF en los grupos NW, OW y OB. La actividad parasimpática (SDNN, RMSSD, pNN50, HF) de los grupos OB y OW evidenció una disminución de los valores en comparación con el grupo NW. La actividad simpática (LF) en el grupo OB y OW presentó mayores valores que en el grupo NW. La relación LF/HF aumentó del grupo NW hacia el OW y el OB (1,6 ± 0,7; 2,5 ± 1,8 y 3,3 ± 0,7). Conclusiones: el sobrepeso y la obesidad presentan una predominancia de la actividad simpática en reposo. Este aumento de la actividad está representado en el dominio de tiempo y frecuencia de la VFC y, además, presenta una correlación importante con la circunferencia de la cintura y la relación cintura/altura.

Small universal spiking neural P systems with dendritic/axonal delays and dendritic trunk/feedback.

In spiking neural P (SN P) systems, neurons are interconnected by means of synapses, and they use spikes to communicate with each other. However, in biology, the complex structure of dendritic tree is also an important part in the communication scheme between neurons since these structures are linked to advanced neural process such as learning and memory formation. In this work, we present a new variant of the SN P systems inspired by diverse dendrite and axon phenomena such as dendritic feedback, dendritic trunk, dendritic delays and axonal delays, respectively. This new variant is referred to as a spiking neural P system with dendritic and axonal computation (DACSN P system). Specifically, we include experimentally proven biological features in the current SN P systems to reduce the computational complexity of the soma by providing it with stable firing patterns through dendritic delays, dendritic feedback and axonal delays. As a consequence, the proposed DACSN P systems use the minimum number of synapses and neurons with simple and homogeneous standard spiking rules. Here, we study the computational capabilities of a DACSN P system. In particular, we prove that DACSN P systems with dendritic and axonal behavior are universal as both number-accepting/generating devices. In addition, we constructed a small universal SN P system using 39 neurons with standard spiking rules to compute any Turing computable function.

Efecto del entrenamiento de fuerza prensil de intensidad ascendente sobre la presión arterial y la cinética de oxigenación muscular en personas mayores hipertensas tipo 1 / Effect of hand grip strength training of ascending intensity on blood pressure and muscle oxygenation kinetics in elderly people with hypertension type 1

Resumen Introducción: La hipertensión arterial presenta una alta prevalencia y es un factor de riesgo importante para el desarrollo de enfermedades cardiovasculares, las cuales afectan mayormente a personas mayores (PM). Como estrategia terapéutica el entrenamiento isométrico de fuerza prensil (EIFP) ha demostrado resultados efectivos en la respuesta hipotensora. Sin embargo, el comportamiento fisiológico de la oxigenación muscular durante y posterior al entrenamiento sigue siendo inespecífica. Objetivo: Analizar los efectos de un protocolo de entrenamiento isométrico de fuerza prensil de intensidad ascendente comparado con un protocolo de entrenamiento isométrico de fuerza prensil al 30% de la contracción máxima voluntaria (CMV) sobre la presión arterial y la cinética de oxigenación muscular en personas mayores hipertensas tipo1. Materiales y métodos: Estudio cuasi-experimental con grupo control en 50 personas mayores físicamente activas (hombres 20 y 30 mujeres) hipertensos tipo 1 farmacológicamente controlados, pertenecientes a la YMCA Santiago, edad promedio 69,6 (± 1,18) años. Muestreo intencional, no probabilístico y aleatorio, considerando criterios de inclusión y exclusión. Se realizó un entrenamiento isométrico de intensidad ascendente (10%, 20%, 30% CMV) de fuerza prensil durante 4 semanas, en un grupo experimental (GE; n: 25), contrastado con un entrenamiento isométrico de fuerza prensil (30 % CMV) grupo control (GC; n: 25). Se valoraron las siguientes variables hemodinámicas y antropométricas: frecuencia cardiaca (FC), presión arterial (PA), oxigenación muscular (OM %), e índice de masa corporal (IMC), analizando los cambios previos y posterior al entrenamiento. Resultados: El análisis estadístico se realizó mediante la prueba de U de Mann-Whitney. En ambos grupos posterior a la intervención disminuyó de manera significativa la presión arterial sistólica (PAS) (GC: 123,6 ± 2,42 a 114,6 ± 2,36 p = 0,01* y GE: 128,1 ± 1,56 a 111,4 ± 2,31 p < 0,00* mmHg) y FC (70,84 ± 1,92 a 64,08 ± 1,87 p = 0,01* y 69,72 ± 2,01 a 64 ± 1,98 p = 0,04* lpm) respectivamente. El mayor cambio de oxigenación muscular (OM) se observa sólo en el GE (57,68 ± 1,34 a 64,56 ± 1,05 p = 0,00* OM%). Conclusión: El entrenamiento isométrico de fuerza prensil de intensidad ascendente es un método valioso y mejor tolerado en personas mayores para disminuir de manera aguda la PA y mejorar el porcentaje de oxigenación muscular posterior al ejercicio. En cuanto al uso de los sensores de espectroscopía del infrarrojo cercano (NIRS) Moxy, podrían desempeñar un papel importante en la mejora del conocimiento científico respecto del metabolismo oxidativo del músculo. No obstante se requieren evaluaciones futuras para determinar los límites basales de oxigenacion muscular.

Abstract Introduction: High blood pressure has a high prevalence and is an important risk factor for the development of cardiovascular diseases, which mostly affect the elderly (PM). As a therapeutic strategy, the isometric hand grip strength training has demonstrated effective results in the hypotensive response. However, the physiological behavior of muscle oxygenation during and after exercise remains unspecified. Objective: Analyze the effects of an isometric training protocol for hand grip strength of ascending intensity compared to an isometric training protocol for hand grip strength at 30% of the maximum voluntary contraction on blood pressure and muscle oxygenation kinetics in hypertensive elderly people type1. Materials and methods: Quasi-experimental study with a control group in 50 physically active elderly people (men 20 and 30 women) pharmacologically controlled type 1 hypertensive, belonging to the YMCA Santiago, average age 69.6 (± 1.18). Intentional, non-probabilistic and random sampling, considering inclusion and exclusion criteria. An ascending intensity training (10%, 20%, 30% of the maximum voluntary contraction CMV) of hand grip strength was performed for 4 weeks, on an experimental group (GE; n: 25), contrasted with an isometric training (30% CMV) control group (GC; n: 25). The following hemodynamic and anthropometric variables were assessed: heart rate (HR), blood pressure (BP), muscle oxygenation (OM%), weight, height and body mass index (BMI), analyzing the changes before and after training. Results: Statistical analysis was performed using the Mann-Whitney U test. In both groups after the intervention, systolic blood pressure (SBP) decreased significantly (GC: 123.6 ± 2.42 to 114.6 ± 2.36 p = 0.01 and GE: 128.1 ± 1, 56 to 111.4 ± 2.31 p <0.000 mmHg) and FC (70.84 ± 1.92 to 64.08 ± 1.87 p = 0.01 and 69.72 ± 2.01 to 64 ± 1.98 p = 0.04 bpm) respectively. The greatest change in muscle oxygenation (OM) is observed only in the GE (57.68 ± 1.34 to 64.56 ± 1.05 p = 0.00 OM%). Conclusion: Isometric training protocol for hand grip strength of ascending intensity is a valuable and better tolerated method in older people to decrease BP and improve the percentage of post-exercise muscle oxygenation. Regarding the use of Moxy near infrared spectroscopy (NIRS) sensors, they could play an important role in improving scientific knowledge regarding oxidative muscle metabolism. However, future evaluations are required to determine baseline muscle oxygenation limits.

Effect of Autonomic Responses After Isometric Training at Different Intensities on Obese People.

BACKGROUND: Arterial hypertension is among the leading causes of mortality worldwide. The primary non-pharmacological management of arterial hypertension is isometric grip training, which has shown better results than pharmacological methods; however, it has not been thoroughly studied in large muscle groups. OBJECTIVE: This study compared the pressor response of isometric exercise training at different intensities, in large groups versus small muscle groups, in sedentary eutrophic and overweight people aged 20-29 years. METHODS: A sample of 93 people (57 people with excess weight and 36 people of normal weight) participated in isometric training for 5 days, subdivided into leg press vs. handgrip strength, with different intensities for each subgroup (30 and 50%, 1 RM). Before and after the 5 training days, Heart Rate Variability (HRV) and systolic and diastolic blood pressure, BSBP-BDBP and PSBP-PDBP, were measured to evaluate the state of sympathetic activation at rest and pressor response. RESULTS: Changes with significant differences (p <0.05) in terms of pre-post training measurements in the eutrophic group were the BSBP-PSBP variables at 30% and 50% 1 RM for manual isometric grip strength. In the excess weight group, the only significant change was the PSBP variable in handgrip strength at 30% 1 RM. It should be noted that in all cases, blood pressure values reduced. CONCLUSION: Isometric strength exercises in large and small muscle groups show a tendency to reduce blood pressure values; however, the isometric handgrip force at 30% 1 RM shows statistically significant reductions in blood pressure values.

Efecto del entrenamiento de la musculatura inspiratoria con válvula umbral sobre la capacidad funcional en mujeres físicamente activas mayores de 60 años / Effect of inspiratory muscle training with threshold valve on functional capacity of physically active women who are older than 60 years of age

Resumen Introducción: Los cambios fisiológicos asociados al envejecimiento generan una serie de modificaciones funcionales, destacando una disminución en la capacidad respiratoria. En este sentido, una estrategia alternativa para mejorar tal condición podría ser el entrenamiento de la musculatura inspiratoria (EMI). Objetivo: Analizar el efecto del EMI con válvula umbral, sobre la capacidad funcional en mujeres físicamente activas mayores de 60 años. Materiales y métodos: Se realizó un EMI con válvula umbral durante 4 semanas, sobre un grupo experimental (GE; n:10), contrastado con un grupo control (GC; n:5). Se valoraron las siguientes variables hemodinámicas y antropométricas: peso, talla, índice de masa corporal (IMC), lactato, doble producto y capacidad funcional, analizando los cambios pre y post entrenamiento. Resultados: en el grupo GE disminuye post intervención la concentración de lactato y la escala de percepción del esfuerzo; 3,16±0,51 a 2,5±0,39 y 5,56 ± 1,81 a 4±2, respectivamente. En el mismo grupo se incrementan los valores de presión inspiratoria máxima (Pimáx) post intervención; 42,11±14,57 a 60,44±14,47. El GC no presentó cambios en sus valores. Conclusión: No se evidencian cambios favorables en los metros recorridos post intervención, sin embargo, el EMI mostró una disminución sobre la concentración de lactato post ejercicio, lo que podría identificar un retraso en la aparición de la fatiga.

Abstract Introduction: Physiological changes associated with aging generate a series of functional modifications, mainly a decrease in respiratory capacity. In this regard, an alternative strategy to improve such a condition could be inspiratory muscle training (IMT). Objective: To analyze the effect of IMT with threshold valve on the functional capacity of physically active women who are older than 60 years of age. Materials and methods: IMT with threshold valve was carried out over a period of 4 weeks, comparing data from the experimental group (GE; n:10) to the control group (GC; n:5). The following hemodynamic and anthropometric variables were assessed: weight, height, body mass index (BMI), lactate, double product (DP) and functional capacity. Pre and post training changes were evaluated. Results: The GE group showed a decrease in both post-intervention lactate concentration (from 3.16±0.51 to 2.5±0.39) and effort perception scale (from 5.56 ± 1.81 to 4±2). On the other hand, this group experienced a post-intervention increase in maximal inspiratory pressure (MIP) from 42.11±14.57 to 60.44±14.47. The GC group did not present changes in its values. Conclusion: Although no evidence was found regarding favorable changes in the walked distance post-intervention, IMT induced a reduction in post-exercise lactate concentration, which could indicate a delay of onset of fatigue.

Análisis del componente rápido de la cinética de recuperación del consumo de oxígeno tras un programa HIIT de 10 días en un grupo de obesos / Analysis of the fast component of the oxygen uptake kinetics after a 10 day long HIIT program in a group of obese men

Resumen Introducción: El sujeto obeso evidencia una disminución de la capacidad funcional (CF), que entre otros factores comprende una cinética del consumo de oxígeno (VO2) más lenta, asociada a una posible relación entre el tejido adiposo y una desregulación crónica del sistema nervioso autónomo, tanto en condiciones de reposo como de ejercicio. Objetivo: Analizar el comportamiento del tau rápido de la cinética off del consumo de oxígeno, luego de la aplicación de un protocolo de ejercicio interválico de alta intensidad y corta duración (HIIT) en un grupo de obesos. Metodología: Se diseñó un estudio comparativo, experimental y longitudinal de corto plazo en cinco sujetos obesos seleccionados por un muestreo no probabilístico intencionado. Se valoraron las siguientes variables: peso, talla, índice de masa corporal (IMC), perímetro de cintura, cinética del consumo de oxígeno y aquellas dependientes del procedimiento. Los datos de VO2 v/s tiempo se ingresaron al Software Graph Pad Prism 6, (Graph Pad Prism versión 6.01 para Windows®) donde se depuraron promediando intervalos de 10 segundos y fueron ajustados a un modelo de función bi-exponencial. Posteriormente se realizó un análisis estadístico descriptivo por medio del Software SigmaPlot 12.5 para Windows® usando las siguientes estadísticas de resumen: media, desviación estándar y rango. Resultados: La edad media fue 25,13 ± 0,62 años. La mayor variación al analizar los resultados en ambas fases del estudio (pre-intervención: 43,09 ± 7,78 s; post-intervención: 26,85 ± 3,78 s) se encontró en el tau rápido del VO2 (p= 0,034). Conclusiones: El entrenamiento de alta intensidad y corta duración realizado en un período de 10 días logra un efecto positivo sobre el componente rápido de la cinética off del VO2 para la población estudiada, mejorando así el tiempo de recuperación posterior al esfuerzo físico.

Abstract Introduction: Obese subjects exhibit a decreased functional capacity (FC) which, among other factors, entails a slower oxygen uptake kinetics associated to a pathological relationship between the adipose tissue and a chronically-deregulated autonomic nervous system, both in resting and exercise conditions. Objective: To analyze the fast-tau behavior of the oxygen consumption off-kinetics, after applying a high intensity and short duration intervallic exercise protocol (HIIT) in a group of obese men. Methodology: An exploratory, comparative, experimental and longitudinal short-term study of 5 obese subjects, selected by intentional non-probabilistic sampling, was designed. Weight, height, body mass index (BMI), waist circumference, kinetics of oxygen consumption and variables related to the procedure were assessed. Data from VO2 v/s time were compiled with Graph Pad Prism v. 6.01 by averaging 10-second intervals and fitted as a bi-exponential model. Subsequently, a descriptive statistical analysis was performed using SigmaPlot v. 12.5, calculating means, standard deviations and ranks. Results: Mean age was 25.13 ± 0.62 years. Highest variation when analyzing the results, in both phases of the study (pre-intervention: 43.09 ± 7.78 s; post-intervention: 26.85 ± 3.78 s), was found in the fast VO2 tau (p=0.034). Conclusion: The high-intensity, short-duration training performed over a 10-day period, achieves a positive effect on the rapid kinetic component of VO2 for the studied population, improving recovery time after physical exertion.

SNAVA-A real-time multi-FPGA multi-model spiking neural network simulation architecture.

Spiking Neural Networks (SNN) for Versatile Applications (SNAVA) simulation platform is a scalable and programmable parallel architecture that supports real-time, large-scale, multi-model SNN computation. This parallel architecture is implemented in modern Field-Programmable Gate Arrays (FPGAs) devices to provide high performance execution and flexibility to support large-scale SNN models. Flexibility is defined in terms of programmability, which allows easy synapse and neuron implementation. This has been achieved by using a special-purpose Processing Elements (PEs) for computing SNNs, and analyzing and customizing the instruction set according to the processing needs to achieve maximum performance with minimum resources. The parallel architecture is interfaced with customized Graphical User Interfaces (GUIs) to configure the SNN's connectivity, to compile the neuron-synapse model and to monitor SNN's activity. Our contribution intends to provide a tool that allows to prototype SNNs faster than on CPU/GPU architectures but significantly cheaper than fabricating a customized neuromorphic chip. This could be potentially valuable to the computational neuroscience and neuromorphic engineering communities.