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The well-known chi-squared goodness-of-fit test for a multinomial distribution is generally biased when the observations are subject to misclassification. In Pardo and Zografos (2000) the problem was considered using a double sampling scheme and phi-divergence test statistics. A new problem appears if the null hypothesis is not simple because it is necessary to give estimators for the unknown parameters. In this paper the minimum phi-divergence estimators are considered and some of their properties are established. The proposed phi-divergence test statistics are obtained by calculating phi-divergences between probability density functions and by replacing parameters by their minimum phi-divergence estimators in the derived expressions. Asymptotic distributions of the new test statistics are also obtained. The testing procedure is illustrated with an example, Depto. de Estadística e Investigación Operativa, Fac. de Ciencias Matemáticas, TRUE, pub

Depth sensing technology has developed rapidly recently due to its broad applications. Time-of-Flight (ToF) is a popular technology in depth sensing because of its advantages in high measuring accuracy and low complexity in image processing. ToF technologies are divided into two kinds: indirect time-of-flight (iToF) and direct Time-of-Flight (dToF). Compared to the iToF, dToF can detect targets at a longer distance by directly calculating the flight time of the laser. To obtain time information, the dToF system requires a Time-to-Digital Converter (TDC). This thesis proposes a system-level model to optimize the TDC parameters for a dToF system used in an autofocus system of a mobile phone. According to the simulation result of the system modeling, a ring-based TDC is chosen and built using a shared and duty-cycled Voltage-Controlled Oscillator (VCO). To decrease the DNL of the TDC, chopping comparators are used in this design. In addition, to save power and area, a new method called double sampling is used to align the coarse and fine phases of the ring based TDC. The proposed TDC achieves a resolution of 100 ps and a DNL of −0.27/+0.37 and an average power of 0.179 mW/TDC, which are smaller than that of state-of-the-art TDCs used in dToF systems. SMIC 55BSC technology is used to design and tape out the TDC., Electrical Engineering | Microelectronics

[EN] This paper proposes a new double sampling scheme for c control chart (DS-c), which was designed to improve the performance of c chart or to reduce the inspection cost. The mathematical expression required to do an exact evaluation of ARL and ASN is deduced. Further, a bi-objective genetic algorithm is implemented to obtain the optimal design of the DS-c scheme. This optimisation is aimed to simultaneously minimising the error probability type II and the ASN, guaranteeing a desired level for the error probability type I. A performance comparison between the double sampling (DS), fixed parameters (FP), variable simple size (VSS) and exponential weighted moving average (EWMA) schemes for the c chart is carried out. The comparison shows that with the implementation of DS-c scheme is obtained a significant reduction of the out of control ARL with a lower ASN respect to FP and a better ARL profile than VSS and EWMA.

[EN] This paper proposes a new double sampling scheme for c control chart (DS-c), which was designed to improve the performance of c chart or to reduce the inspection cost. The mathematical expression required to do an exact evaluation of ARL and ASN is deduced. Further, a bi-objective genetic algorithm is implemented to obtain the optimal design of the DS-c scheme. This optimisation is aimed to simultaneously minimising the error probability type II and the ASN, guaranteeing a desired level for the error probability type I. A performance comparison between the double sampling (DS), fixed parameters (FP), variable simple size (VSS) and exponential weighted moving average (EWMA) schemes for the c chart is carried out. The comparison shows that with the implementation of DS-c scheme is obtained a significant reduction of the out of control ARL with a lower ASN respect to FP and a better ARL profile than VSS and EWMA.

[EN] In some real situations there is the need of controlling p variables of a multivariate process, where p1 out of these p variables are easy and inexpensive to monitor, while the p(2)=p-p(1) remaining variables are difficult and/or expensive to measure. However, this set of p(2) variables is important to quickly detect the process shifts. This paper develops a control chart based on the T-2 statistic where normally only the set of p1 variables is monitored, and only when the T-2 value falls in a warning area the rest of variables (p(2)) are measured and combined with the sample values from the p(1) variables, in order to obtain a new T-2 statistic. This new chart is the double dimension T-2 (DDT2) control chart. The ARL of the DDT2 chart is obtained and the chart's parameters are optimized using genetic algorithms with the aim of maximizing the performance in detecting a given process shift. The optimized DDT2 chart is compared against the standard T-2 chart when all the variables are monitored. The results show that the DDT2 clearly outperforms T-2 chart in terms of cost, and in some cases even detects process shifts faster than the latter. In addition, friendly software has been developed with the objective of promoting the real application of this new control chart.

[EN] In some real situations there is the need of controlling p variables of a multivariate process, where p1 out of these p variables are easy and inexpensive to monitor, while the p(2)=p-p(1) remaining variables are difficult and/or expensive to measure. However, this set of p(2) variables is important to quickly detect the process shifts. This paper develops a control chart based on the T-2 statistic where normally only the set of p1 variables is monitored, and only when the T-2 value falls in a warning area the rest of variables (p(2)) are measured and combined with the sample values from the p(1) variables, in order to obtain a new T-2 statistic. This new chart is the double dimension T-2 (DDT2) control chart. The ARL of the DDT2 chart is obtained and the chart's parameters are optimized using genetic algorithms with the aim of maximizing the performance in detecting a given process shift. The optimized DDT2 chart is compared against the standard T-2 chart when all the variables are monitored. The results show that the DDT2 clearly outperforms T-2 chart in terms of cost, and in some cases even detects process shifts faster than the latter. In addition, friendly software has been developed with the objective of promoting the real application of this new control chart.

This thesis presents an incremental ?? capacitance-to-digital converter (CDC) that serves as an interface circuit for a MEMS-based pressure sensor. The thesis presents a systematic analysis of the CDC and compares different CDC architectures. A novel non-linear CDC is also proposed and analysed. Energy-efficiency of the CDC is improved by implementation of various design techniques like double sampling, system-level chopping and a novel inverter-based OTA. The CDC has been designed in such a way that it can operate with either an on-chip or external pressure sensor. The CDC can be tuned to compensate for a wide range of baseline capacitance. The CDC operates over a pressure range of 0-1.3 bar and achieves a pressure resolution of 1e?5 bar (equivalent to a resolution of 16 bits). The CDC is implemented in NXP 0.16?m 1P6M technology. The circuit design and layout of the CDC are presented. The CDC consumes 2.33?A from a 1.2V supply resulting in an energy consumption of only 2.01nJ, a significant improvement over the state-of-the-art., Microelectronics & Computer Engineering, Electrical Engineering, Mathematics and Computer Science

This thesis presents an incremental ?? capacitance-to-digital converter (CDC) that serves as an interface circuit for a MEMS-based pressure sensor. The thesis presents a systematic analysis of the CDC and compares different CDC architectures. A novel non-linear CDC is also proposed and analysed. Energy-efficiency of the CDC is improved by implementation of various design techniques like double sampling, system-level chopping and a novel inverter-based OTA. The CDC has been designed in such a way that it can operate with either an on-chip or external pressure sensor. The CDC can be tuned to compensate for a wide range of baseline capacitance. The CDC operates over a pressure range of 0-1.3 bar and achieves a pressure resolution of 1e?5 bar (equivalent to a resolution of 16 bits). The CDC is implemented in NXP 0.16?m 1P6M technology. The circuit design and layout of the CDC are presented. The CDC consumes 2.33?A from a 1.2V supply resulting in an energy consumption of only 2.01nJ, a significant improvement over the state-of-the-art., Microelectronics & Computer Engineering, Electrical Engineering, Mathematics and Computer Science

Assessing the spatial structure of abundance of a species is a basic requirement to carry out adequate conservation strategies. However, existing attempts to predict species abundance, particularly in absolute units and on large scales, are scarce and have led to weak results. In this work we present a scheme to obtain, in an affordable way, a predictive model of absolute animal abundance on large scales based on the modelling of data obtained from local ecological knowledge (LEK) and its calibration. To exemplify this scheme, we build and validate a predictive absolute abundance model of the endangered terrestrial tortoise Testudo graeca in Southeast Iberian Peninsula. For that purpose, we collected distribution and relative abundance data of T. graeca using a low cost methodology, such as LEK, by means of interviewing shepherds. The information from LEK was employed to build a predictive habitat-based model of relative abundance. The relative abundance model was transformed into an absolute abundance model by means of calibration with a classical absolute abundance sampling method such as distance sampling. The obtained absolute abundance model predicted the observed absolute abundances values well in independent locations when compared with other works (R 2 = 36%) and thus can offer a cost-effective predictive ability. Our results show that reliable habitat-based predictive maps of absolute species abundance on regional scales can be obtained starting from low cost sampling methods of relative abundance, such as LEK, and its calibration.

In the present study, we propose a general class of estimators for population mean of the study variable in the presence of non-response using auxiliary information under double sampling. The expression of mean squared error (MSE) of the proposed class of estimators is derived under double (two-stage) sampling. Some estimators are also derived from the proposed class by allocating the suitable values of constants used. Comparisons of the proposed strategy with the usual unbiased estimator and other estimators are carried out. The results obtained are illustrated numerically using an empirical sample considered in the literature., Peer Reviewed

In this article, we introduce minimum divergence estimators of parameters of a binary response model when data are subject to false-positive misclassification and obtained using a double-sampling plan. Under this set up, the problem of goodness-of-fit is considered and divergence-based confidence intervals (CIs) for a population proportion parameter are derived. A simulation experiment is carried out to compare the coverage probabilities of the new CIs. An application to real data is also given., Depto. de Estadística e Investigación Operativa, Fac. de Ciencias Matemáticas, TRUE, pub

A 28-MHz wideband switched-capacitor (SC) bandpass filter employs an N-path technique and implements transmission zeros in the transfer function to achieve high attenuation. A modified SC biquadratic filter architecture is proposed to achieve high-speed operation. Implemented in a 0.35-mu m CMOS process, the bandpass filter operates at 28-MHz center frequency with a 3.84-MHz bandwidth and adjacent-channel attenuation of more than 35 dB. At 3-V supply, the filter measures a dynamic range of 37 dB at the 1\% THD3 point while dissipating 19.6-mW per pole and occupying a chip area of 1.65 mm(2).

A 28-MHz wideband switched-capacitor (SC) bandpass filter employs an N-path technique and implements transmission zeros in the transfer function to achieve high attenuation. A modified SC biquadratic filter architecture is proposed to achieve high-speed operation. Implemented in a 0.35-mu m CMOS process, the bandpass filter operates at 28-MHz center frequency with a 3.84-MHz bandwidth and adjacent-channel attenuation of more than 35 dB. At 3-V supply, the filter measures a dynamic range of 37 dB at the 1\% THD3 point while dissipating 19.6-mW per pole and occupying a chip area of 1.65 mm(2).

A 28-MHz wideband switched-capacitor (SC) bandpass filter employs an N-path technique and implements transmission zeros in the transfer function to achieve high attenuation. A modified SC biquadratic filter architecture is proposed to achieve high-speed operation. Implemented in a 0.35-mu m CMOS process, the bandpass filter operates at 28-MHz center frequency with a 3.84-MHz bandwidth and adjacent-channel attenuation of more than 35 dB. At 3-V supply, the filter measures a dynamic range of 37 dB at the 1\% THD3 point while dissipating 19.6-mW per pole and occupying a chip area of 1.65 mm(2).

Multivariate control charts are used to monitor a process when more than one quality variable associated with the process is being observed. The multivariate exponentially weighted moving average (MEWMA) control chart is one of the most commonly recommended tools for multivariate process monitoring. The standard practice, when using the MEWMA control chart, is to take samples of fixed size at regular sampling intervals for each variable. In the first part of this dissertation, MEWMA control charts based on sequential sampling schemes with two possible stages are investigated. When sequential sampling with two possible stages is used, observations at a sampling point are taken in two groups, and the number of groups actually taken is a random variable that depends on the data. The basic idea is that sampling starts with a small initial group of observations, and no additional sampling is done at this point if there is no indication of a problem with the process. But if there is some indication of a problem with the process then an additional group of observations is taken at this sampling point. The performance of the sequential sampling (SS) MEWMA control chart is compared to the performance of standard control charts. It is shown that that the SS MEWMA chart is substantially more efficient in detecting changes in the process mean vector than standard control charts that do not use sequential sampling. Also the situation is considered where different variables may have different measurement costs. MEWMA control charts with unequal sample sizes based on differing measurement costs are investigated in order to improve the performance of process monitoring. Sequential sampling plans are applied to MEWMA control charts with unequal sample sizes and compared to the standard MEWMA control charts with a fixed sample size. The steady-state average time to signal (SSATS) is computed using simulation and compared for some selected sets of sample sizes. When different variable

A 1-V switched-capacitor (SC) bandpass sigma-delta (SigmaDelta) modulator is realized using a high-speed switched-opamp (SO) technique with a sampling frequency of up to 50 MHz, which is improved ten times more than prior 1-V SO designs and comparable to the performance of the state-of-the-art SC circuits that operate at much higher supply voltages. On the system level, a fast-settling double-sampling SC biquadratic filter architecture is proposed to achieve high-speed operation. A low-voltage double-sampling finite-gain-compensation technique is employed to realize a high-resolution SigmaDelta modulator using only low-dc-gain opamps to maximize the speed and to reduce power dissipation. On the circuit level, a fast-switching methodology is proposed for the design of the switchable opamps to achieve a switching frequency up to 50 MHz. Implemented in a 0.35-mum CMOS process (V-TP = 0.82 V and V-TN = 0.65 V) and at 1-V supply, the modulator achieves a measured peak signal-to-noise-and-distortion ratio (SNDR) of 42.3 dB at 10.7 MHz with a signal bandwidth of 200 kHz, while dissipating 12 mW and occupying a chip area of 1.3 mm(2).

The possibility of implementing the double-sampling (DS) technique in IIR first- and second-order switched-capacitor (SC) decimators is considered. The DS-SC circuits that result are designed using the same procedure as standard IIR decimators, and only a different SC implementation results with a reorganized clock phasing. The main advantage is that the time allowed for the op-amps to settle can be equal to the output sampling period rather than one half of it. Using the proposed DS decimators allows to design high-frequency SC filtering systems (an anti-aliasing SC decimator filter and a "core" DS-SC filter) where the op-amp speed requirements are the same in each block

The fishing by the sluice, employed in the brackish fish ponds of Arcachon Bay, catchs only the migrating eels. The exploitation by this process is not more than the 18 percent of the biomass. The structure of the migrating eels caught in winter 1977-78 was estimated using the double sampling method with length as strata. The sex­ratio was about 1.1. The males migrate to the sea from 3 to 7 years after of the brackish water life (maximum 5 years old) and the females leave the fish ponds, generally from 5 to 9 years after (maximum 7 years old). The estimated mean lengths, 37.5 cm for the males and 49.8 cm for the females, were much smaller than-those which were estimated in the Italian "Vallis", La pêche à l'écluse, utilisée dans les lagunes aménagées du Bassin d'Arcachon, ne capture que des anguilles migratrices. L'exploitation des anguilles par ce procédé ne dépasse pas 18 % de la biomasse en place. La structure des anguilles de dévalaison pêchées en hiver 1977-78 a été estimée par la méthode de double échantillonnage stratifié par classe de taille. Le sex-ratio est voisin de 1,1. Les mâles migrent vers la mer entre 3 et 7 ans (maximum à 5 ans) et les femelles quittent les réservoirs généralement entre 5 et 9 ans (maximum à 7 ans). Les tailles moyennes obte­nues, 37,5 cm pour les mâles et 49,8 cm pour les femelles, sont sensiblement inférieures à celles qui sont observées dans les "Vallis" italiens.

The fishing by the sluice, employed in the brackish fish ponds of Arcachon Bay, catchs only the migrating eels. The exploitation by this process is not more than the 18 percent of the biomass. The structure of the migrating eels caught in winter 1977-78 was estimated using the double sampling method with length as strata. The sex­ratio was about 1.1. The males migrate to the sea from 3 to 7 years after of the brackish water life (maximum 5 years old) and the females leave the fish ponds, generally from 5 to 9 years after (maximum 7 years old). The estimated mean lengths, 37.5 cm for the males and 49.8 cm for the females, were much smaller than-those which were estimated in the Italian "Vallis", La pêche à l'écluse, utilisée dans les lagunes aménagées du Bassin d'Arcachon, ne capture que des anguilles migratrices. L'exploitation des anguilles par ce procédé ne dépasse pas 18 % de la biomasse en place. La structure des anguilles de dévalaison pêchées en hiver 1977-78 a été estimée par la méthode de double échantillonnage stratifié par classe de taille. Le sex-ratio est voisin de 1,1. Les mâles migrent vers la mer entre 3 et 7 ans (maximum à 5 ans) et les femelles quittent les réservoirs généralement entre 5 et 9 ans (maximum à 7 ans). Les tailles moyennes obte­nues, 37,5 cm pour les mâles et 49,8 cm pour les femelles, sont sensiblement inférieures à celles qui sont observées dans les "Vallis" italiens.

The fishing by the sluice, employed in the brackish fish ponds of Arcachon Bay, catchs only the migrating eels. The exploitation by this process is not more than the 18 percent of the biomass. The structure of the migrating eels caught in winter 1977-78 was estimated using the double sampling method with length as strata. The sex­ratio was about 1.1. The males migrate to the sea from 3 to 7 years after of the brackish water life (maximum 5 years old) and the females leave the fish ponds, generally from 5 to 9 years after (maximum 7 years old). The estimated mean lengths, 37.5 cm for the males and 49.8 cm for the females, were much smaller than-those which were estimated in the Italian "Vallis", La pêche à l'écluse, utilisée dans les lagunes aménagées du Bassin d'Arcachon, ne capture que des anguilles migratrices. L'exploitation des anguilles par ce procédé ne dépasse pas 18 % de la biomasse en place. La structure des anguilles de dévalaison pêchées en hiver 1977-78 a été estimée par la méthode de double échantillonnage stratifié par classe de taille. Le sex-ratio est voisin de 1,1. Les mâles migrent vers la mer entre 3 et 7 ans (maximum à 5 ans) et les femelles quittent les réservoirs généralement entre 5 et 9 ans (maximum à 7 ans). Les tailles moyennes obte­nues, 37,5 cm pour les mâles et 49,8 cm pour les femelles, sont sensiblement inférieures à celles qui sont observées dans les "Vallis" italiens.

The fishing by the sluice, employed in the brackish fish ponds of Arcachon Bay, catchs only the migrating eels. The exploitation by this process is not more than the 18 percent of the biomass. The structure of the migrating eels caught in winter 1977-78 was estimated using the double sampling method with length as strata. The sex­ratio was about 1.1. The males migrate to the sea from 3 to 7 years after of the brackish water life (maximum 5 years old) and the females leave the fish ponds, generally from 5 to 9 years after (maximum 7 years old). The estimated mean lengths, 37.5 cm for the males and 49.8 cm for the females, were much smaller than-those which were estimated in the Italian "Vallis", La pêche à l'écluse, utilisée dans les lagunes aménagées du Bassin d'Arcachon, ne capture que des anguilles migratrices. L'exploitation des anguilles par ce procédé ne dépasse pas 18 % de la biomasse en place. La structure des anguilles de dévalaison pêchées en hiver 1977-78 a été estimée par la méthode de double échantillonnage stratifié par classe de taille. Le sex-ratio est voisin de 1,1. Les mâles migrent vers la mer entre 3 et 7 ans (maximum à 5 ans) et les femelles quittent les réservoirs généralement entre 5 et 9 ans (maximum à 7 ans). Les tailles moyennes obte­nues, 37,5 cm pour les mâles et 49,8 cm pour les femelles, sont sensiblement inférieures à celles qui sont observées dans les "Vallis" italiens.