Alberto Gonzalez - Academia.edu (original) (raw)

Papers by Alberto Gonzalez

In this article part of the techniques and developments we are carrying out within the INCO2 grou... more In this article part of the techniques and developments we are carrying out within the INCO2 group are reported. Results follow the interdisciplinary approach with which we tackle signal processing applications. Chosen case studies show di erent stages of development: We present algorithms already completed which are being used in practical applications as well as new ideas that may represent a starting point, and which are expected to deliver good results in a short and medium term.

2011 19th European Signal Processing Conference, 2011

One of the main limitations of microphone array algorithms for audio applications has been their ... more One of the main limitations of microphone array algorithms for audio applications has been their high computational cost in real acoustic environments when real-time signal processing is absolutely required. Regarding audio/speech signal processing, beamforming algorithms have been used for the recovery of acoustic signals from their observations when they are corrupted by noise, reverberation and other interfering signals. In order to reduce their high computational load, frequency-based filtering have been used to achieve a real time application. Our research focuses on the use of different multicore/manycore platforms in order to achieve a real time beamforming application in the time domain. Efficient algorithms has been proposed and tested in several devices and results have shown that GPU implementation of beamforming design and filtering outperforms multicore implementation in computational cost terms. The performance obtained suggests that GPU implementation paves the way fo...

2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO), 2012

Affine projection algorithm encompasses a family of configurable algorithms designed to improve t... more Affine projection algorithm encompasses a family of configurable algorithms designed to improve the performance of other adaptive algorithms, mainly LMS based ones, especially when input data is highly correlated. The computational cost of the affine projection algorithm depends largely on the projection order, which in turn conditions the speed of convergence, thus high speed of convergence implies usually high computational cost. Some real-time applications (especially multichannel) using the affine projection algorithm can not be implemented in the existing general-purpose hardware, because of this several improvements of the affine projection algorithm have been proposed to make it more computationally efficient and more versatile in terms of performance. This paper outlines the evolution of the affine projection algorithm and its variants, in order to get an efficient and self-reconfigurable algorithm. Furthermore new improvements over the existing low cost and variable step si...

2004 12th European Signal Processing Conference, 2004

A comparative study of the multichannel Affine Projection (AP), the Fast Transversal Filter (FTF)... more A comparative study of the multichannel Affine Projection (AP), the Fast Transversal Filter (FTF), the filtered-X LMS (FXLMS) and the Recursive Least Squares (RLS) algorithms is presented for active noise control (ANC) systems. This study is based on simulations using real data and laboratory experiments, and is focused on: their computational cost, their convergence properties, their stability and their ability to create quiet zones around listener ears. The performance of the AP algorithm in the real system suggests its use in ANC systems as an alternative to the classical multichannel FXLMS since it provides meaningful attenuation levels, lower convergence time and similar computational cost.

Integrated Computer-Aided Engineering, 2012

The use of many-core processors such as general purpose Graphic Processing Units (GPUs) has recen... more The use of many-core processors such as general purpose Graphic Processing Units (GPUs) has recently become attractive for the efficient implementation of signal processing algorithms for communication systems. This is due to the costeffectiveness of GPUs together with their potential capability of parallel processing. This paper presents an implementation of the widely employed fixed-complexity sphere decoder on GPUs, which allows to considerably decrease the computational time required for the data detection stage in multiple-input multiple-output systems. Both, the hard-and soft-output versions of the method have been implemented. Speedup results show the proposed GPU implementation boosts the runtime of the parallel execution of the methods in a high performance multi-core CPU. In addition, the throughput of the algorithm is evaluated and is shown to outperform other recent implementations and to fulfill the real-time requirements of several LTE configurations.

Signal Processing, 2012

Variable order affine projection algorithms have been recently presented to be used when not only... more Variable order affine projection algorithms have been recently presented to be used when not only the convergence speed of the algorithm has to be adjusted but also its computational cost and its final residual error. These kind of affine projection (AP) algorithms improve the standard AP algorithm performance at steady state by reducing the residual mean square error. Furthermore these algorithms optimize computational cost by dynamically adjusting their projection order to convergence speed requirements. The main cost of the standard AP algorithm is due to the matrix inversion that appears in the coefficient update equation. Most efforts to decrease the computational cost of these algorithms have focused on the optimization of this matrix inversion. This paper deals with optimization of the computational cost of variable order AP algorithms by recursive calculation of the inverse signal matrix. Thus, a fast exact variable order AP algorithm is proposed. Exact iterative expressions to calculate the inverse matrix when the algorithm projection order either increases or decreases are incorporated into

Procedia Computer Science, 2013

Multiple-input multiple-output (MIMO) detection techniques can vary significantly in complexity a... more Multiple-input multiple-output (MIMO) detection techniques can vary significantly in complexity and detection performance. Finding the optimal Maximum Likelihood (ML) solution with high throughput was limited by the computational performance. In order to achieve high throughput non-ML algorithms were introduced, having degraded detection performance and lower complexity. In this paper we present a new parallel algorithm, inspired by the Sphere Detector (SD) algorithm, which can efficiently solve the ML detection of the MIMO systems with high throughput on parallel architectures. We also give an overview on how it is possible to map the Parallel Sphere Detector (PSD) onto GP-GPUs, however different parallel architectures are also suitable for adapting the presented algorithm.

The Journal of Supercomputing, 2012

Multi-core systems allow the e cient implementation of signal processing algorithms for communica... more Multi-core systems allow the e cient implementation of signal processing algorithms for communication systems due to their high parallel processing capabilities. In this paper, we present a high-throughput multi-core implementation of a fixed-complexity tree-search-based detector interesting for MIMO wireless communication systems. Experimental results confirm that this implementation allows to accelerate the data detection stage for di↵erent constellation sizes and number of subcarriers.

The Journal of Supercomputing, 2011

Massive convolution is the basic operation in multichannel acoustic signal processing. This field... more Massive convolution is the basic operation in multichannel acoustic signal processing. This field has experienced a major development in recent years. One reason for this has been the increase in the number of sound sources used in playback applications available to users. Another reason is the growing need to incorporate new effects and to improve the hearing experience. Massive convolution requires high computing capacity. GPUs offer the possibility of parallelizing these operations. This allows us to obtain the processing result in much shorter time and to free up CPU resources. One important aspect lies in the possibility of overlapping the transfer of data from CPU to GPU and vice versa with the computation, in order to carry out real-time applications. Thus, a synthesis of 3D sound scenes could be achieved with only a peer-to-peer music streaming environment using a simple GPU in your computer, while the CPU in the computer is being used for other tasks. Nowadays, these effects are obtained in theaters or funfairs at a very high cost, requiring a large quantity of resources. Thus, our work focuses on two mains points: to describe an efficient massive convolution implementation and to incorporate this task to real-time multichannel-sound applications.

Journal of Multimedia, 2007

An efficient version of the affine projection (AP) algorithm, which is called FXAP-AC throughout ... more An efficient version of the affine projection (AP) algorithm, which is called FXAP-AC throughout the paper, is presented. This algorithm uses the filtered-x structure instead of the modified structure which is required for the implementation of the AP algorithm when the desired signal is not available, for instance in Active Noise Control (ANC) applications. The conventional AP algorithm for ANC, which is based on the modified structure (MFXAP), provides good performance. However the filtered-x structure is advisable for practical cases since it achieves a meaningful computational saving avoiding the additional filtering needed by the modified structure without significantly affect the performance in practice. This fact is specially important in multichannel applications where the computational resources are limited. Furthermore, different low-cost strategies already proposed in the conventional AP algorithm such as the fast error vector calculation or the efficient computation of coefficient update can be applied to the FXAP. Throughout this paper, the efficient computation of coefficient update is developed for the FXAP (resulting in the FXAP-AC). This strategy can be meaningfully combined with others previously reported to achieve very fast and robust FXAP algorithms. Experimental results validate the use of the proposed algorithm for practical applications.

IET Signal Processing, 2013

This paper is focused on the necessity to improve the performance of the affine projection (AP) a... more This paper is focused on the necessity to improve the performance of the affine projection (AP) algorithm for active noise control (ANC) applications. The proposed algorithms are evaluated regarding their steady-state behavior, their convergence speed and their computational complexity. To this end, different strategies recently applied to the AP for channel identification are proposed for multichannel ANC. These strategies are based either on a variable step size, an evolving projection order, or the combination of both strategies. The developed efficient versions of the AP algorithm use the modified filtered-x structure, which exhibits faster convergence than other filtering schemes. Simulation results show that the proposed approaches exhibit better performance than the conventional AP algorithm and represent a meaningful choice for practical multichannel ANC applications.

IEEE Transactions on Signal Processing, 2012

Experimental theoretical methodology for determination of inertial pressure drop distribution and... more Experimental theoretical methodology for determination of inertial pressure drop distribution and pore structure properties in wall-flow diesel particulate filters (DPFs). Energy. 36(12):6731-6744.

Graphics Processing Units (GPUs) have been recently used as coprocessors capable of performing ta... more Graphics Processing Units (GPUs) have been recently used as coprocessors capable of performing tasks that are not necessarily related to graphics processing in order to optimize computing resources. The use of GPUs has being extended to a wide variety of intensive-computation applications among which audio processing is included. However data transactions between the CPU and the GPU and vice versa have questioned the viability of GPUs for applications in which direct and real-time interaction between microphone and loudspeaker is required. One of the audio applications that requires real-time feedback is adaptive channel identification. Particularly, when the partitioned Least Mean Squares (LMS) algorithm is used in the frequency domain, the size of input-data buffers and filters and how they can be managed in order to successfully exploit the GPU resources is an important key in the design process. This paper discusses the design and implementation of all the processing blocks of an adaptive channel identification system on a GPU, proposing a GPU implementation that can be easily adapted to any acoustic scenario, while freeing up CPU resources for other tasks.

Proceedings of the 22nd International Meshing Roundtable, 2014

A new parallel algorithm for simultaneous untangling and smoothing of tetrahedral meshes is propo... more A new parallel algorithm for simultaneous untangling and smoothing of tetrahedral meshes is proposed in this paper. We provide a detailed analysis of its performance on shared-memory many-core computer architectures. This performance analysis includes the evaluation of execution time, parallel scalability, load balancing, and parallelism bottlenecks. Additionally, we compare the impact of three previously published graph coloring procedures on the performance of our parallel algorithm. We use six benchmark meshes with a wide range of sizes. Using these experimental data sets, we describe the behavior of the parallel algorithm for different data sizes. We demonstrate that this algorithm is highly scalable when it runs on two different high-performance many-core computers with up to 128 processors. However, some parallel deterioration is observed. Here, we analyze the main causes of this parallel deterioration.

Journal of Educational and Social Research, 2013

Top-down programming is procedural programming style, which design begins by defining the solutio... more Top-down programming is procedural programming style, which design begins by defining the solution at the highest level of functionality and breaking it down further and further into small routines that can be easily documented and coded. The main aim of this paper is a revisiting of the generic top down programming approach in solving and implementation of an efficient algorithm. we went into these research because programming is traditionally taught using bottom up approach where details of syntax and implementation of data structure are the predominant concept. The top down approach proposed focuses instead on understanding the abstractions represented by the classical data structures without regard to their physical implementation. This paper discusses the benefits of this approach and how it is used in an object oriented world.

Applied Acoustics, 2014

ABSTRACT This paper proposes a nonlinear active noise control (ANC) system based on convex combin... more ABSTRACT This paper proposes a nonlinear active noise control (ANC) system based on convex combination of a functional link artificial neural network (FLANN) and a Volterra filter. Simulation study reveals enhanced noise cancelation performance of the proposed ANC system over the ones based on its component filters.

2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO), 2012

The use of adaptive algorithms in multichannel equalization has become essential to compensate ro... more The use of adaptive algorithms in multichannel equalization has become essential to compensate room effects of real sound reproduction systems. Due to the high complexity and number of compensation filters that involve these multiple-input multiple-output (MIMO) systems, a compromise has to be taken to provide good equalization without increasing the complexity of the adaptive algorithm. The impulse responses of a multichannel equalizer are usually long and exhibit a high (or unknown) degree of sparsity, which results in least-mean-square (LMS) type algorithms showing slow convergence speed. Recently, proportionate adaptive schemes have been introduced to accelerate filter convergence and to exploit sparsity in echo cancellation and active noise control systems. Moreover, it is possible to reduce the error of the adaptive filters by biassing the weights, specially under low signal-to-noise ratio condition. In this paper we propose a biased proportionate adaptive algorithm for multic...

2011 19th European Signal Processing Conference, 2011

Proportionate adaptive schemes have been proposed to exploit sparsity and accelerate filter conve... more Proportionate adaptive schemes have been proposed to exploit sparsity and accelerate filter convergence in acoustic echo cancellation. Recently, combinations of adaptive filters have been extended to operate with proportionate schemes, in order to achieve more robust operation when the actual degree of sparsity of the optimal solution is unknown. Furthermore, it is possible to exploit the asymmetric distribution of adaptation energy in proportionate schemes to reduce the overall steady-state misadjustment. In this contribution, we explain how these novel adaptive filtering structures, which have been proposed and tested mainly for echo cancellation, can also be effectively extended to improve the usual performance trade-offs that appear in active noise control scenarios by introducing some minor modifications. Experimental results in realistic scenarios show that the proposed schemes provide an interesting alternative to the traditional use of a single adaptive filter.

Journal of AOAC INTERNATIONAL, 2007

A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesti... more A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesticides in different varieties of lettuce (Lactuca sativum) was developed. Lettuce samples were extracted by homogenization with acetone and partitioned into ethyl acetatecyclohexane. Subsequent sample cleanup was not needed. Final determination was made by capillary gas chromatography (GC) with electron-capture detection (ECD). Confirmation analysis of pesticides was performed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recovery by the GCECD method obtained for these compounds varied from 66.4 to 119.2 with relative standard deviations <7.7. The GCECD method has good linearity, and the detection limit for the pesticides studied varied from 0.1 to 3.8 g/kg. The proposed method was used to determine pesticide levels in different types of lettuce grown in soils from experimental fields.

In this article part of the techniques and developments we are carrying out within the INCO2 grou... more In this article part of the techniques and developments we are carrying out within the INCO2 group are reported. Results follow the interdisciplinary approach with which we tackle signal processing applications. Chosen case studies show di erent stages of development: We present algorithms already completed which are being used in practical applications as well as new ideas that may represent a starting point, and which are expected to deliver good results in a short and medium term.

2011 19th European Signal Processing Conference, 2011

One of the main limitations of microphone array algorithms for audio applications has been their ... more One of the main limitations of microphone array algorithms for audio applications has been their high computational cost in real acoustic environments when real-time signal processing is absolutely required. Regarding audio/speech signal processing, beamforming algorithms have been used for the recovery of acoustic signals from their observations when they are corrupted by noise, reverberation and other interfering signals. In order to reduce their high computational load, frequency-based filtering have been used to achieve a real time application. Our research focuses on the use of different multicore/manycore platforms in order to achieve a real time beamforming application in the time domain. Efficient algorithms has been proposed and tested in several devices and results have shown that GPU implementation of beamforming design and filtering outperforms multicore implementation in computational cost terms. The performance obtained suggests that GPU implementation paves the way fo...

2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO), 2012

Affine projection algorithm encompasses a family of configurable algorithms designed to improve t... more Affine projection algorithm encompasses a family of configurable algorithms designed to improve the performance of other adaptive algorithms, mainly LMS based ones, especially when input data is highly correlated. The computational cost of the affine projection algorithm depends largely on the projection order, which in turn conditions the speed of convergence, thus high speed of convergence implies usually high computational cost. Some real-time applications (especially multichannel) using the affine projection algorithm can not be implemented in the existing general-purpose hardware, because of this several improvements of the affine projection algorithm have been proposed to make it more computationally efficient and more versatile in terms of performance. This paper outlines the evolution of the affine projection algorithm and its variants, in order to get an efficient and self-reconfigurable algorithm. Furthermore new improvements over the existing low cost and variable step si...

2004 12th European Signal Processing Conference, 2004

A comparative study of the multichannel Affine Projection (AP), the Fast Transversal Filter (FTF)... more A comparative study of the multichannel Affine Projection (AP), the Fast Transversal Filter (FTF), the filtered-X LMS (FXLMS) and the Recursive Least Squares (RLS) algorithms is presented for active noise control (ANC) systems. This study is based on simulations using real data and laboratory experiments, and is focused on: their computational cost, their convergence properties, their stability and their ability to create quiet zones around listener ears. The performance of the AP algorithm in the real system suggests its use in ANC systems as an alternative to the classical multichannel FXLMS since it provides meaningful attenuation levels, lower convergence time and similar computational cost.

Integrated Computer-Aided Engineering, 2012

The use of many-core processors such as general purpose Graphic Processing Units (GPUs) has recen... more The use of many-core processors such as general purpose Graphic Processing Units (GPUs) has recently become attractive for the efficient implementation of signal processing algorithms for communication systems. This is due to the costeffectiveness of GPUs together with their potential capability of parallel processing. This paper presents an implementation of the widely employed fixed-complexity sphere decoder on GPUs, which allows to considerably decrease the computational time required for the data detection stage in multiple-input multiple-output systems. Both, the hard-and soft-output versions of the method have been implemented. Speedup results show the proposed GPU implementation boosts the runtime of the parallel execution of the methods in a high performance multi-core CPU. In addition, the throughput of the algorithm is evaluated and is shown to outperform other recent implementations and to fulfill the real-time requirements of several LTE configurations.

Signal Processing, 2012

Variable order affine projection algorithms have been recently presented to be used when not only... more Variable order affine projection algorithms have been recently presented to be used when not only the convergence speed of the algorithm has to be adjusted but also its computational cost and its final residual error. These kind of affine projection (AP) algorithms improve the standard AP algorithm performance at steady state by reducing the residual mean square error. Furthermore these algorithms optimize computational cost by dynamically adjusting their projection order to convergence speed requirements. The main cost of the standard AP algorithm is due to the matrix inversion that appears in the coefficient update equation. Most efforts to decrease the computational cost of these algorithms have focused on the optimization of this matrix inversion. This paper deals with optimization of the computational cost of variable order AP algorithms by recursive calculation of the inverse signal matrix. Thus, a fast exact variable order AP algorithm is proposed. Exact iterative expressions to calculate the inverse matrix when the algorithm projection order either increases or decreases are incorporated into

Procedia Computer Science, 2013

Multiple-input multiple-output (MIMO) detection techniques can vary significantly in complexity a... more Multiple-input multiple-output (MIMO) detection techniques can vary significantly in complexity and detection performance. Finding the optimal Maximum Likelihood (ML) solution with high throughput was limited by the computational performance. In order to achieve high throughput non-ML algorithms were introduced, having degraded detection performance and lower complexity. In this paper we present a new parallel algorithm, inspired by the Sphere Detector (SD) algorithm, which can efficiently solve the ML detection of the MIMO systems with high throughput on parallel architectures. We also give an overview on how it is possible to map the Parallel Sphere Detector (PSD) onto GP-GPUs, however different parallel architectures are also suitable for adapting the presented algorithm.

The Journal of Supercomputing, 2012

Multi-core systems allow the e cient implementation of signal processing algorithms for communica... more Multi-core systems allow the e cient implementation of signal processing algorithms for communication systems due to their high parallel processing capabilities. In this paper, we present a high-throughput multi-core implementation of a fixed-complexity tree-search-based detector interesting for MIMO wireless communication systems. Experimental results confirm that this implementation allows to accelerate the data detection stage for di↵erent constellation sizes and number of subcarriers.

The Journal of Supercomputing, 2011

Massive convolution is the basic operation in multichannel acoustic signal processing. This field... more Massive convolution is the basic operation in multichannel acoustic signal processing. This field has experienced a major development in recent years. One reason for this has been the increase in the number of sound sources used in playback applications available to users. Another reason is the growing need to incorporate new effects and to improve the hearing experience. Massive convolution requires high computing capacity. GPUs offer the possibility of parallelizing these operations. This allows us to obtain the processing result in much shorter time and to free up CPU resources. One important aspect lies in the possibility of overlapping the transfer of data from CPU to GPU and vice versa with the computation, in order to carry out real-time applications. Thus, a synthesis of 3D sound scenes could be achieved with only a peer-to-peer music streaming environment using a simple GPU in your computer, while the CPU in the computer is being used for other tasks. Nowadays, these effects are obtained in theaters or funfairs at a very high cost, requiring a large quantity of resources. Thus, our work focuses on two mains points: to describe an efficient massive convolution implementation and to incorporate this task to real-time multichannel-sound applications.

Journal of Multimedia, 2007

An efficient version of the affine projection (AP) algorithm, which is called FXAP-AC throughout ... more An efficient version of the affine projection (AP) algorithm, which is called FXAP-AC throughout the paper, is presented. This algorithm uses the filtered-x structure instead of the modified structure which is required for the implementation of the AP algorithm when the desired signal is not available, for instance in Active Noise Control (ANC) applications. The conventional AP algorithm for ANC, which is based on the modified structure (MFXAP), provides good performance. However the filtered-x structure is advisable for practical cases since it achieves a meaningful computational saving avoiding the additional filtering needed by the modified structure without significantly affect the performance in practice. This fact is specially important in multichannel applications where the computational resources are limited. Furthermore, different low-cost strategies already proposed in the conventional AP algorithm such as the fast error vector calculation or the efficient computation of coefficient update can be applied to the FXAP. Throughout this paper, the efficient computation of coefficient update is developed for the FXAP (resulting in the FXAP-AC). This strategy can be meaningfully combined with others previously reported to achieve very fast and robust FXAP algorithms. Experimental results validate the use of the proposed algorithm for practical applications.

IET Signal Processing, 2013

This paper is focused on the necessity to improve the performance of the affine projection (AP) a... more This paper is focused on the necessity to improve the performance of the affine projection (AP) algorithm for active noise control (ANC) applications. The proposed algorithms are evaluated regarding their steady-state behavior, their convergence speed and their computational complexity. To this end, different strategies recently applied to the AP for channel identification are proposed for multichannel ANC. These strategies are based either on a variable step size, an evolving projection order, or the combination of both strategies. The developed efficient versions of the AP algorithm use the modified filtered-x structure, which exhibits faster convergence than other filtering schemes. Simulation results show that the proposed approaches exhibit better performance than the conventional AP algorithm and represent a meaningful choice for practical multichannel ANC applications.

IEEE Transactions on Signal Processing, 2012

Experimental theoretical methodology for determination of inertial pressure drop distribution and... more Experimental theoretical methodology for determination of inertial pressure drop distribution and pore structure properties in wall-flow diesel particulate filters (DPFs). Energy. 36(12):6731-6744.

Graphics Processing Units (GPUs) have been recently used as coprocessors capable of performing ta... more Graphics Processing Units (GPUs) have been recently used as coprocessors capable of performing tasks that are not necessarily related to graphics processing in order to optimize computing resources. The use of GPUs has being extended to a wide variety of intensive-computation applications among which audio processing is included. However data transactions between the CPU and the GPU and vice versa have questioned the viability of GPUs for applications in which direct and real-time interaction between microphone and loudspeaker is required. One of the audio applications that requires real-time feedback is adaptive channel identification. Particularly, when the partitioned Least Mean Squares (LMS) algorithm is used in the frequency domain, the size of input-data buffers and filters and how they can be managed in order to successfully exploit the GPU resources is an important key in the design process. This paper discusses the design and implementation of all the processing blocks of an adaptive channel identification system on a GPU, proposing a GPU implementation that can be easily adapted to any acoustic scenario, while freeing up CPU resources for other tasks.

Proceedings of the 22nd International Meshing Roundtable, 2014

A new parallel algorithm for simultaneous untangling and smoothing of tetrahedral meshes is propo... more A new parallel algorithm for simultaneous untangling and smoothing of tetrahedral meshes is proposed in this paper. We provide a detailed analysis of its performance on shared-memory many-core computer architectures. This performance analysis includes the evaluation of execution time, parallel scalability, load balancing, and parallelism bottlenecks. Additionally, we compare the impact of three previously published graph coloring procedures on the performance of our parallel algorithm. We use six benchmark meshes with a wide range of sizes. Using these experimental data sets, we describe the behavior of the parallel algorithm for different data sizes. We demonstrate that this algorithm is highly scalable when it runs on two different high-performance many-core computers with up to 128 processors. However, some parallel deterioration is observed. Here, we analyze the main causes of this parallel deterioration.

Journal of Educational and Social Research, 2013

Top-down programming is procedural programming style, which design begins by defining the solutio... more Top-down programming is procedural programming style, which design begins by defining the solution at the highest level of functionality and breaking it down further and further into small routines that can be easily documented and coded. The main aim of this paper is a revisiting of the generic top down programming approach in solving and implementation of an efficient algorithm. we went into these research because programming is traditionally taught using bottom up approach where details of syntax and implementation of data structure are the predominant concept. The top down approach proposed focuses instead on understanding the abstractions represented by the classical data structures without regard to their physical implementation. This paper discusses the benefits of this approach and how it is used in an object oriented world.

Applied Acoustics, 2014

ABSTRACT This paper proposes a nonlinear active noise control (ANC) system based on convex combin... more ABSTRACT This paper proposes a nonlinear active noise control (ANC) system based on convex combination of a functional link artificial neural network (FLANN) and a Volterra filter. Simulation study reveals enhanced noise cancelation performance of the proposed ANC system over the ones based on its component filters.

2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO), 2012

The use of adaptive algorithms in multichannel equalization has become essential to compensate ro... more The use of adaptive algorithms in multichannel equalization has become essential to compensate room effects of real sound reproduction systems. Due to the high complexity and number of compensation filters that involve these multiple-input multiple-output (MIMO) systems, a compromise has to be taken to provide good equalization without increasing the complexity of the adaptive algorithm. The impulse responses of a multichannel equalizer are usually long and exhibit a high (or unknown) degree of sparsity, which results in least-mean-square (LMS) type algorithms showing slow convergence speed. Recently, proportionate adaptive schemes have been introduced to accelerate filter convergence and to exploit sparsity in echo cancellation and active noise control systems. Moreover, it is possible to reduce the error of the adaptive filters by biassing the weights, specially under low signal-to-noise ratio condition. In this paper we propose a biased proportionate adaptive algorithm for multic...

2011 19th European Signal Processing Conference, 2011

Proportionate adaptive schemes have been proposed to exploit sparsity and accelerate filter conve... more Proportionate adaptive schemes have been proposed to exploit sparsity and accelerate filter convergence in acoustic echo cancellation. Recently, combinations of adaptive filters have been extended to operate with proportionate schemes, in order to achieve more robust operation when the actual degree of sparsity of the optimal solution is unknown. Furthermore, it is possible to exploit the asymmetric distribution of adaptation energy in proportionate schemes to reduce the overall steady-state misadjustment. In this contribution, we explain how these novel adaptive filtering structures, which have been proposed and tested mainly for echo cancellation, can also be effectively extended to improve the usual performance trade-offs that appear in active noise control scenarios by introducing some minor modifications. Experimental results in realistic scenarios show that the proposed schemes provide an interesting alternative to the traditional use of a single adaptive filter.

Journal of AOAC INTERNATIONAL, 2007

A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesti... more A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesticides in different varieties of lettuce (Lactuca sativum) was developed. Lettuce samples were extracted by homogenization with acetone and partitioned into ethyl acetatecyclohexane. Subsequent sample cleanup was not needed. Final determination was made by capillary gas chromatography (GC) with electron-capture detection (ECD). Confirmation analysis of pesticides was performed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recovery by the GCECD method obtained for these compounds varied from 66.4 to 119.2 with relative standard deviations <7.7. The GCECD method has good linearity, and the detection limit for the pesticides studied varied from 0.1 to 3.8 g/kg. The proposed method was used to determine pesticide levels in different types of lettuce grown in soils from experimental fields.