HDL-level design offers important advantages for the application of watermarking to IP cores, but... more HDL-level design offers important advantages for the application of watermarking to IP cores, but its complexity also requires tools automating these watermarking algorithms. A new tool for signature distribution through combinational logic is proposed in this work. IPP@HDL, a previously proposed high-level watermarking technique, has been employed for evaluating the tool. IPP@HDL relies on spreading the bits of a digital signature at the HDL design level using combinational logic included within the original system. The development of this new tool for the signature distribution has not only extended and eased the applicability of this IPP technique, but it has also improved the signature hosting process itself. Three algorithms were studied in order to develop this automated tool. The selection of a cost function determines the best hosting solutions in terms of area and performance penalties on the IP core to protect. An 1D-DWT core and MD5 and SHA1 digital signatures were used i...
Watermarking techniques for Intellectual Property Protection (IPP) of IP cores at the HDL design ... more Watermarking techniques for Intellectual Property Protection (IPP) of IP cores at the HDL design level are proposed in this paper. The basic idea relies on spreading the bits of a digital signature at the HDL design level using combinational logic or look-up structures included within the original system. The techniques also include a secure and non-destructive signature extraction process. Furthermore,
Orthogonal Frequency division multiplexing (OFDM) spread spectrum technique, sometimes also calle... more Orthogonal Frequency division multiplexing (OFDM) spread spectrum technique, sometimes also called multi-carrier or discrete multi-tone modulation, are used in bandwidth-efficient communication systems in the presence of channel distortion. The benefits of OFDM are high spectral efficiency, resiliency to RF interference, and lower multi-path distortion. OFDM is the basis for the European digital audio broadcasting (DAB) standard, the global asymmetric digital
ABSTRACT This paper presents the use of wavelet cores for a full reconfigurable electrocardiogram... more ABSTRACT This paper presents the use of wavelet cores for a full reconfigurable electrocardiogram signal (ECG) acquisition system. The system is compound by two reconfigurable devices, a FPGA and a FPAA. The FPAA is in charge of the ECG signal acquisition, since this device is a versatile and reconfigurable analog front-end for biosignals. The FPGA is in charge of FPAA configuration, digital signal processing and information extraction such as heart beat rate and others. Wavelet analysis has become a powerful tool for ECG signal processing since it perfectly fits ECG signal shape. The use of these cores has been integrated in the LabVIEW FPGA module development tool that makes possible to employ VHDL cores within the usual LabVIEW graphical programming environment, thus freeing the designer from tedious and time consuming design of communication interfaces. This enables rapid test and graphical representation of results.
2007 International Conference on Field Programmable Logic and Applications, 2007
This work describes the application of both field programmable analog arrays (FPAAs) and field pr... more This work describes the application of both field programmable analog arrays (FPAAs) and field programmable gate arrays (FPGAs) for signal conditioning and processing in smart sensor applications. The main objective is to exploit their natural reconfiguration capabilities, which will expand the application field to more complex measurement and control systems. On the other hand, the introduction of IEEE 1451-compliant sensors
Page 1. Top (2009) 17: 256287 DOI 10.1007/s11750-008-0057-0 ORIGINAL PAPER Timetabling optimizat... more Page 1. Top (2009) 17: 256287 DOI 10.1007/s11750-008-0057-0 ORIGINAL PAPER Timetabling optimization of a single railway track line with sensitivity analysis Enrique Castillo · Inmaculada Gallego · José María Ureña · José María Coronado ...
In this paper a review of some decomposition techniques previously given by the authors to solve ... more In this paper a review of some decomposition techniques previously given by the authors to solve bi-level problems is presented within a unified formulation, and a new variant is investigated. Different reliability-based optimization problems in engineering works are formulated and solved: (a) the failure-probability safety-factor problem that makes the compatibility of the classical approach, based on safety-factors; and the modern probability-based approach possible; (b) a modern reliability-based approach where the design is based on minimizing initial/construction costs subject to failure-probability and safety-factor bounds for all failure modes; (c) minimizing the expected total cost of a structure, including maintenance and construction, which depend on the failure probabilities; and (d) a mixed model minimizing the expected total cost adding failure-probability and safety-factor bounds for all failure modes. In these four problems, the objective consists of selecting the values of the design variables that minimize the corresponding cost functions subject to some reliability conditions together with geometric and code constraints. The solution becomes complex because the evaluation of failure probabilities using first-order reliability methods (FORM) involves one optimization problem per failure mode, so that decomposition methods are used to solve the problem. The proposed methods use standard optimization frameworks to obtain the reliability indices and to solve the global problem within a decomposition scheme. An advantage of these approaches is that the optimization procedure and the reliability calculations are decoupled. In addition, a sensitivity analysis is performed using a method that consists of transforming the data parameters into artificial variables, and using the dual associated variables. To illustrate the methods, a breakwater design example is used.
In this paper, general bivariate distributions with conditionals in truncated weighted families a... more In this paper, general bivariate distributions with conditionals in truncated weighted families are derived. Some examples and several interesting particular families are presented. Within these models, maximum likelihood estimates must usually be implemented numerically. The feasibility of this approach is illustrated using an example involving a simulated data set.
Two classes of k-dimensional distributions with generalized Pareto conditionals are characterized... more Two classes of k-dimensional distributions with generalized Pareto conditionals are characterized. This subsumes and extends earlier work on distributions with Pareto conditionals.
This paper presents an electrocardiogram (ECG) acquisition system based on reconfigurable devices... more This paper presents an electrocardiogram (ECG) acquisition system based on reconfigurable devices. This system allows redesigning the analog conditioning stage thanks to the use of a Field Programmable Analog Array (FPAA) device, which may be adapted to the requirements of the signal shape and/or medical specifications. Simulated and real ECG signals have been acquired using this system in a three-lead configuration. A detailed study of its technical features has been carried out, showing good suitability for ECG acquisition. Further digital ECG signal processing is performed on a Field Programmable Gate Array (FPGA) device, which has allowed different digital configurations to be tested, including FIR and wavelet filtering and identification of wave features such as the QRS complex. In addition, the FPGA device is in charge of FPAA reconfiguration. Thus, the pairing of FPAA and FPGA devices conforms a compact and versatile bio-signal acquisition platform. This platform has shown very good performance with different types of electrodes, and has also demonstrated the dynamic reconfiguration capabilities of these devices, which enable, for example, the tuning of gain and bandwidth as required by different input conditions and ECG application requirements. The analyzed performance parameters provide values such as 102dB CMRR (Common-Mode Rejection Ratio), 14-bit ADC resolution, and 75dB SNR (signal-to-noise ratio), among others, thus satisfying the minimum requirements for clinical use.
This paper illustrates the use of a reconfigurable system for fetal electrocardiogram (FECG) esti... more This paper illustrates the use of a reconfigurable system for fetal electrocardiogram (FECG) estimation from mother's abdomen ECG measurements. The system is based on two different reconfigurable devices. Initially, a field-programmable analog array (FPAA) device implements the analog reconfigurable preprocessing for ECG signal acquisition. The signal processing chain continues onto a field-programmable gate array (FPGA) device, which contains all the communication and interfacing protocols along with specific digital signal processing blocks required for fundamental period extraction from FECG waveforms. The synergy between these devices provides the system the ability to change any necessary parameter during the acquisition process for enhancing the result. The use of a FPGA allows implementing different algorithms for FECG signal extraction, such as adaptive signal filtering. Preliminary works employ commercially available development platforms for test experiments, which suffice for the processing of real FECG signals from biomedical databases, as the presented results illustrate.
Journal of Statistical Computation and Simulation, 2009
Sensitivity analysis in regression is concerned with assessing the sensitivity of the results of ... more Sensitivity analysis in regression is concerned with assessing the sensitivity of the results of a regression model (e.g., the objective function, the regression parameters, and the fitted values) to changes in the data. Sensitivity analysis in least squares linear regression has seen a great surge of research activities over the last three decades. By contrast, sensitivity analysis in non-linear regression has received very little attention. This paper deals with the problem of local sensitivity analysis in non-linear regression. Closed-form general formulas are provided for the sensitivities of three standard methods for the estimation of the parameters of a non-linear regression model based on a set of data. These methods are the least squares, the minimax, and the least absolute value methods. The effectiveness of the proposed measures is illustrated by application to several non-linear models including the ultrasonic data and the onion yield data. The proposed sensitivity measures are shown to deal effectively with the detection of influential observations in non-linear regression models.
HDL-level design offers important advantages for the application of watermarking to IP cores, but... more HDL-level design offers important advantages for the application of watermarking to IP cores, but its complexity also requires tools automating these watermarking algorithms. A new tool for signature distribution through combinational logic is proposed in this work. IPP@HDL, a previously proposed high-level watermarking technique, has been employed for evaluating the tool. IPP@HDL relies on spreading the bits of a digital signature at the HDL design level using combinational logic included within the original system. The development of this new tool for the signature distribution has not only extended and eased the applicability of this IPP technique, but it has also improved the signature hosting process itself. Three algorithms were studied in order to develop this automated tool. The selection of a cost function determines the best hosting solutions in terms of area and performance penalties on the IP core to protect. An 1D-DWT core and MD5 and SHA1 digital signatures were used i...
Watermarking techniques for Intellectual Property Protection (IPP) of IP cores at the HDL design ... more Watermarking techniques for Intellectual Property Protection (IPP) of IP cores at the HDL design level are proposed in this paper. The basic idea relies on spreading the bits of a digital signature at the HDL design level using combinational logic or look-up structures included within the original system. The techniques also include a secure and non-destructive signature extraction process. Furthermore,
Orthogonal Frequency division multiplexing (OFDM) spread spectrum technique, sometimes also calle... more Orthogonal Frequency division multiplexing (OFDM) spread spectrum technique, sometimes also called multi-carrier or discrete multi-tone modulation, are used in bandwidth-efficient communication systems in the presence of channel distortion. The benefits of OFDM are high spectral efficiency, resiliency to RF interference, and lower multi-path distortion. OFDM is the basis for the European digital audio broadcasting (DAB) standard, the global asymmetric digital
ABSTRACT This paper presents the use of wavelet cores for a full reconfigurable electrocardiogram... more ABSTRACT This paper presents the use of wavelet cores for a full reconfigurable electrocardiogram signal (ECG) acquisition system. The system is compound by two reconfigurable devices, a FPGA and a FPAA. The FPAA is in charge of the ECG signal acquisition, since this device is a versatile and reconfigurable analog front-end for biosignals. The FPGA is in charge of FPAA configuration, digital signal processing and information extraction such as heart beat rate and others. Wavelet analysis has become a powerful tool for ECG signal processing since it perfectly fits ECG signal shape. The use of these cores has been integrated in the LabVIEW FPGA module development tool that makes possible to employ VHDL cores within the usual LabVIEW graphical programming environment, thus freeing the designer from tedious and time consuming design of communication interfaces. This enables rapid test and graphical representation of results.
2007 International Conference on Field Programmable Logic and Applications, 2007
This work describes the application of both field programmable analog arrays (FPAAs) and field pr... more This work describes the application of both field programmable analog arrays (FPAAs) and field programmable gate arrays (FPGAs) for signal conditioning and processing in smart sensor applications. The main objective is to exploit their natural reconfiguration capabilities, which will expand the application field to more complex measurement and control systems. On the other hand, the introduction of IEEE 1451-compliant sensors
Page 1. Top (2009) 17: 256287 DOI 10.1007/s11750-008-0057-0 ORIGINAL PAPER Timetabling optimizat... more Page 1. Top (2009) 17: 256287 DOI 10.1007/s11750-008-0057-0 ORIGINAL PAPER Timetabling optimization of a single railway track line with sensitivity analysis Enrique Castillo · Inmaculada Gallego · José María Ureña · José María Coronado ...
In this paper a review of some decomposition techniques previously given by the authors to solve ... more In this paper a review of some decomposition techniques previously given by the authors to solve bi-level problems is presented within a unified formulation, and a new variant is investigated. Different reliability-based optimization problems in engineering works are formulated and solved: (a) the failure-probability safety-factor problem that makes the compatibility of the classical approach, based on safety-factors; and the modern probability-based approach possible; (b) a modern reliability-based approach where the design is based on minimizing initial/construction costs subject to failure-probability and safety-factor bounds for all failure modes; (c) minimizing the expected total cost of a structure, including maintenance and construction, which depend on the failure probabilities; and (d) a mixed model minimizing the expected total cost adding failure-probability and safety-factor bounds for all failure modes. In these four problems, the objective consists of selecting the values of the design variables that minimize the corresponding cost functions subject to some reliability conditions together with geometric and code constraints. The solution becomes complex because the evaluation of failure probabilities using first-order reliability methods (FORM) involves one optimization problem per failure mode, so that decomposition methods are used to solve the problem. The proposed methods use standard optimization frameworks to obtain the reliability indices and to solve the global problem within a decomposition scheme. An advantage of these approaches is that the optimization procedure and the reliability calculations are decoupled. In addition, a sensitivity analysis is performed using a method that consists of transforming the data parameters into artificial variables, and using the dual associated variables. To illustrate the methods, a breakwater design example is used.
In this paper, general bivariate distributions with conditionals in truncated weighted families a... more In this paper, general bivariate distributions with conditionals in truncated weighted families are derived. Some examples and several interesting particular families are presented. Within these models, maximum likelihood estimates must usually be implemented numerically. The feasibility of this approach is illustrated using an example involving a simulated data set.
Two classes of k-dimensional distributions with generalized Pareto conditionals are characterized... more Two classes of k-dimensional distributions with generalized Pareto conditionals are characterized. This subsumes and extends earlier work on distributions with Pareto conditionals.
This paper presents an electrocardiogram (ECG) acquisition system based on reconfigurable devices... more This paper presents an electrocardiogram (ECG) acquisition system based on reconfigurable devices. This system allows redesigning the analog conditioning stage thanks to the use of a Field Programmable Analog Array (FPAA) device, which may be adapted to the requirements of the signal shape and/or medical specifications. Simulated and real ECG signals have been acquired using this system in a three-lead configuration. A detailed study of its technical features has been carried out, showing good suitability for ECG acquisition. Further digital ECG signal processing is performed on a Field Programmable Gate Array (FPGA) device, which has allowed different digital configurations to be tested, including FIR and wavelet filtering and identification of wave features such as the QRS complex. In addition, the FPGA device is in charge of FPAA reconfiguration. Thus, the pairing of FPAA and FPGA devices conforms a compact and versatile bio-signal acquisition platform. This platform has shown very good performance with different types of electrodes, and has also demonstrated the dynamic reconfiguration capabilities of these devices, which enable, for example, the tuning of gain and bandwidth as required by different input conditions and ECG application requirements. The analyzed performance parameters provide values such as 102dB CMRR (Common-Mode Rejection Ratio), 14-bit ADC resolution, and 75dB SNR (signal-to-noise ratio), among others, thus satisfying the minimum requirements for clinical use.
This paper illustrates the use of a reconfigurable system for fetal electrocardiogram (FECG) esti... more This paper illustrates the use of a reconfigurable system for fetal electrocardiogram (FECG) estimation from mother's abdomen ECG measurements. The system is based on two different reconfigurable devices. Initially, a field-programmable analog array (FPAA) device implements the analog reconfigurable preprocessing for ECG signal acquisition. The signal processing chain continues onto a field-programmable gate array (FPGA) device, which contains all the communication and interfacing protocols along with specific digital signal processing blocks required for fundamental period extraction from FECG waveforms. The synergy between these devices provides the system the ability to change any necessary parameter during the acquisition process for enhancing the result. The use of a FPGA allows implementing different algorithms for FECG signal extraction, such as adaptive signal filtering. Preliminary works employ commercially available development platforms for test experiments, which suffice for the processing of real FECG signals from biomedical databases, as the presented results illustrate.
Journal of Statistical Computation and Simulation, 2009
Sensitivity analysis in regression is concerned with assessing the sensitivity of the results of ... more Sensitivity analysis in regression is concerned with assessing the sensitivity of the results of a regression model (e.g., the objective function, the regression parameters, and the fitted values) to changes in the data. Sensitivity analysis in least squares linear regression has seen a great surge of research activities over the last three decades. By contrast, sensitivity analysis in non-linear regression has received very little attention. This paper deals with the problem of local sensitivity analysis in non-linear regression. Closed-form general formulas are provided for the sensitivities of three standard methods for the estimation of the parameters of a non-linear regression model based on a set of data. These methods are the least squares, the minimax, and the least absolute value methods. The effectiveness of the proposed measures is illustrated by application to several non-linear models including the ultrasonic data and the onion yield data. The proposed sensitivity measures are shown to deal effectively with the detection of influential observations in non-linear regression models.
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