Low Noise Measurement Systems Research Papers (original) (raw)

2025

Evaluation of the land surface albedos by employing the bidirectional reflectance distribution function (BRDF) models is one of the important problems in remote sensing. As is known, the retrieval process is an inverse problem. In Proposition 3 of , the authors consider that the number of independent observations should be greater than the number of the unknown parameters to describe the physical model as an overdetermined system, then the inverse process can be solved. However as Li et al (1998) pointed out that such a requirement can be hardly satisfied even in the coming EOS era, the inversion procedure is always underdetermined in some sense. Therefore, in order to solve the BRDF inversion problem, some new technique must be developed. Generally speaking, the inverse problems are ill-posed. Therefore, some regularization technique should be applied to suppress the ill-posedness. One kind of way to alleviate the ill-posedness is incorporating with some apriori knowledge which has been developed in . This is actually a constrained least squares error (LSE) method since the apriori knowledge can be considered as some kind of constraints to the solution. Another kind of way is by numerical truncated singular value decomposition by employing the hotspot remote sensing data . In this paper, we consider a new solution method, i.e., the l 1 norm solution method, which iteratively solves the kernel-driven bidirectional reflectance distribution function (BRDF) models for retrieval of land surface albedos. This method, is based on searching for an interior point solution for the problem in the feasible solution set. This method can always find a set of suitable BRDF coefficients for poor sampled data. Numerical performance is given for the widely used 18 data sets among the 73 data sets ].

2025, IEEE Transactions on Mobile Computing

The location of mobile terminals in cellular networks is an important problem with applications in resource allocation, location sensitive browsing, and emergency communications. Finding cost effective location estimation techniques that are robust to Non-Line of Sight (NLOS) propagation, quantization, and measurement noise is a key problem in this area. Quantized time difference of arrival (TDoA) and received signal strength (RSS) measurements can be made simultaneously by CDMA cellular networks at low cost. The different sources of errors for each measurement type cause RSS and TDoA measurements to contain independent information about mobile terminal location. This paper applies data fusion to combine the information of RSS and TDoA measurements to calculate a superior location estimate. Nonparametric estimation methods, that are robust to variations of measurement noise and quantization, are employed to calculate the location estimates. It is shown how the data fusion location estimators are robust, provide lower error than the estimators based on the individual measurements, and have low implementation cost.

2025, 2008 IEEE International Conference on Robotics and Biomimetics

This paper presents a novel algorithm for line extraction from 2D laser range finder which has excellent precision to determine of line boundary, while having efficient speed and low complexity. This algorithm is more robust in measurement noise and cluttered data and fit a line to a set of uncertain points via Hough transform and recursive split formalism. In this algorithm first the data from laser is segmented to separate regions by determining start and end points throw Hough transform. After removing noisy or sparse points lines are extracted with a fast recursive split algorithm. Furthermore, it has good real-time capability to integrate the information of laser scanner into the navigation algorithm of the mobile robot and it is implemented on NAJI V rescue robot platform.

2024, ACM SIGGRAPH Computer Graphics

High-quality Monte Carlo image synthesis needs to use realistic bidirectional reflectance distribution functions (BRDFs) based on acquired reflectance data. In this study, we propose a novel model that contributes to solving memory problems and measurement noise problems of BRDFs. The model is a composite associative memory model constructed by integration of Kohonen's Self Organizing Feature Map (SOM), Mass Attraction Network (MAN), and it has been tested on data set acquired by Matusik et al.. Because it is based on table-lookups, it can't be categorized in analytical reflectance models. We show that our approach has acceptable compactness. We also show that it has more accuracy than both analytical BRDF models and Lawrence et al.'s table-based model. In this work, we are able to create images efficiently under global illumination with less memory requirements.

2024

Diabetes mellitus, an illness due the inefficiency of the pancreas in managing plasma glucose level, can result intensive side difficulties and death. Since the diabetes system is a nonlinear system the control of it associated with specific problems. For effective control, the use of fuzzy logic theory seems to be appropriate. In this study, Bergman model of type 1 diabetes is considered and is tried to design a fuzzy Proportional Integral (PI) controller base on Mamdani-type structure. In the design procedure, less linguistic rules are used so the proposed controller is less complicated than other existing fuzzy controllers. In order to evaluate the performance of the proposed controller, a control input and a disturbance input are derived from authoritative references and the system is tested on standard initial states for 10 h. The comparison with previous studies shows that the proposed controller reduces the blood glucose level in less time; however less insulin dosage in comparison with other optimal controllers is used.

2024, Journal of Electromyography and Kinesiology

This paper reviews data acquisition and signal processing issues relative to producing an amplitude estimate of surface EMG. The paper covers two principle areas. First, methods for reducing noise, artefact and interference in recorded EMG are described. Wherever possible noise should be reduced at the source via appropriate skin preparation, and the use of well designed active electrodes and signal recording instrumentation. Despite these efforts, some noise will always accompany the desired signal, thus signal processing techniques for noise reduction (e.g. band-pass filtering, adaptive noise cancellation filters and filters based on the wavelet transform) are discussed. Second, methods for estimating the amplitude of the EMG are reviewed. Most advanced, highfidelity methods consist of six sequential stages: noise rejection/filtering, whitening, multiple-channel combination, amplitude demodulation, smoothing and relinearization. Theoretical and experimental research related to each of the above topics is reviewed and the current recommended practices are described.

2024, Systems and Control Letters

This paper addresses the problems of navigation and source localization by mobile agents based on the range to a single source, in addition to relative velocity readings. The contribution of the paper is twofold: i) necessary and sufficient conditions on the observability of the nonlinear system are derived, which are useful for trajectory planning and motion control of the agent; and ii) a nonlinear system, which given the input and output of the system is regarded as linear time-varying, is proposed and a Kalman filter is applied to successfully estimate the system state. Simulation results are presented in the presence of realistic measurement noise that illustrate the performance achieved with the proposed solution.

2024

Detection and measurement of ultra-weak photon emission (UWPE) from biological samples is a promising tool with potential use in several fields such as agriculture, environmental science, food science and biomedicine. A measurement system especially designed to detect UWPE, and an application in sanitary control of natural water resources is presented here. The system was implemented based on a dark-chamber with a photomultiplier module (PMT) cooled with a microprocessor controlled thermoelectric device coupled. The PMT detects the UWPE from the biological sample under measurement. The performance evaluation of the measuring system in terms of dark-noise and bacteria detection was performed in order to assure that it is able to realize UWPE measurements for the proposed application. The samples under test were comprised of a series of 3 control cultures of standard Escherichia coli strain, used as control, and other 3 water samples collected from a river close to a metropolitan area...

2024, Applied Acoustics

The Community Tolerance Level (CTL) is a new indicator which characterizes the impact of aircraft noise around local airport. It corresponds to the exposure sound level (DENL or DNL) where 50% of the population is highly annoyed. Inspired by this indicator, this paper aims at calculating the Real Estate Tolerance Level (RETL) which corresponds to the exposure sound level where a property price is 50% depreciated compared to the price of the same property which would be situated in an area whose DENL is below 50 dB(A). The use of a notarial database analyzed with the Hedonic Price Model (HPM) made it possible to calculate the percentage of property price depreciation around CDG airport, with 1-dB steps of DENL, and so far to calculate the RETL. 19,891 house transactions and 23,264 apartments have been localized with a Geographic Information Systems (GIS) and crossed with the Sound Environment Curves provided by Airport of Paris. The RETL value for single houses and for apartments around CDG is 75.8 dB. It is comparable to the mean CTL value which has been estimated to 73.3 dB from the DNL data of 43 airports over the world (about 73.9 dB from DENL data). The RETL is predictable without field survey and could characterize the impact of aircraft noise around local airports. It could be a good indicator to follow the evolution of population tolerance over the years.

2024, Proceedings of the 8th ACM SIGCOMM conference on Internet measurement

Recently, it has been reported that certain access ISPs are surreptitiously blocking their customers from uploading data using the popular BitTorrent file-sharing protocol. The reports have sparked an intense and wide-ranging policy debate on network neutrality and ISP traffic management practices. However, to date, end users lack access to measurement tools that can detect whether their access ISPs are blocking their BitTorrent traffic. And since ISPs do not voluntarily disclose their traffic management policies, no one knows how widely BitTorrent traffic blocking is deployed in the current Internet. In this paper, we address this problem by designing an easy-to-use tool to detect BitTorrent blocking and by presenting results from a widely used public deployment of the tool.

2024, Lecture Notes in Computer Science

The main goals of an on-board fault detection and diagnosis system in a vehicle are mainly to avoid damage to the vehicle and prevent dangerous situations for occupants. These goals can achieved by triggering correcting actions or at least by warning the driver. However, a vehicle is a complex system where monitoring and diagnosis is challenging due to inherent uncertainty caused by noisy sensors, measurements and non modeled dynamics. In this work a new approach is presented to perform online diagnosis in a vehicle, which is able to deal with measurement noise presence. Our method analyzes with fuzzy logic and neural networks the residuals obtained by the comparison between sensors measurements and the output of a mathematical model of vehicle dynamics. Experiments shows promising results when faults are induced during different vehicle maneuvers simulations.

2024, Transportation Research Record

2024, Choices. The Magazine of Food, Farm, and Resources Issues

No Plane, Big Gain: Airport Noise and Residential Property Values in the Reno-Sparks Area The hedonic price method is used to explore the relationship between residential property values and airport noise in the Reno-Sparks area. Empirical results suggest there is a statistically significant negative relationship between airport noise and residential property values, but that the disamenity value diminishes as distance from the airport increases.

2024, Applications of Geometric Algebra in Computer Science and Engineering

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2024, Journal of Crystal Growth

Photodiodes with a cutoff wavelength extended in the infrared-region up to 2.4~sm have been fabricated using a mismatched Ga1 _~In~As/InAs~P1-y /InP double heterostructure prepared by the low pressure MOCVD epitaxial technique on InP substrate. The ternary composition Ga02In0 8As was chosen to tailor the bandgap of the Ga1_~InÃs absorption layer to long wavelength detector requirements. An InAs~,P1~, (y = 0.5) graded composition layer followed by an (InAs~P1-y /Ga1~InÃs) superlattice acting as a barrier to dislocation propagation has been used to accommodate the 1.8% lattice mismatch between the InP substrate and the Ga0 21n08As active layer of the device. Room temperature typical dark current 'd of the PIN photodiode at-I V reverse bias, is about 8X10 4 A/cm2.

2024, Biological Cybernetics

Partial coherence measures the linear relationship between two signals after the influence of a third signal has been removed. Gersch proposed in 1970 that partial coherence could be used to identify sources of driving for multivariate time series. This idea, referred to in this paper as Gersch Causality, has received wide acceptance and has been applied extensively to a variety of fields in the signal processing community. Neurobiological data from a given sensor include both the signals of interest and other unrelated processes collectively referred to as measurement noise. We show that partialcoherence-based Gersch Causality is extremely sensitive to signal-to-noise ratio; that is, for a group of three or more simultaneously recorded time series, the time series with the highest signal-to-noise ratio (i.e., relatively noise free) is often identified as the "driver" of the group, irrespective of the true underlying patterns of connectivity. This hypothesis is tested both theoretically and on experimental time series acquired from limbic brain structures during the theta rhythm.

2024, Applications of Geometric Algebra in Computer Science and Engineering

2024, Remote Sensing of Environment

Z differentiate among geological materials and vegetation using thermal infrared spectra, radiometric measurements' require corrections for local temperature variations and reflected radiation. A laboratory technique is described for the determination of spectral emissivity signatures for natural geological samples using a Fourier Transform Infrared Spectrometer and the self-emission of the scene. The approach described does not require control of the sample temperature. A quantitative assessment of uncertainties is presented. Comparison of the emissivity measurements from natural geological specimens with hemispherical reflectance data gave an average difference of about 0.01 in emissivity, except near strong features of the spectra. The technique is applicable to field measurements of high-emissivity objects.

2024, 2009 IEEE 17th Signal Processing and Communications Applications Conference

Bu bildiride, gerçek zaman WiMAX (3.5 GHz) radyo kanallarÕnda kör uyarlanÕr ö÷renme algoritmalarÕnÕn deneysel baúarÕmlarÕ de÷erlendirilmektedir. ÇalÕúmada, en çok kullanÕlan kör denkleútirme tekni÷i sabit büyüklük algoritmasÕ (Constant Modulus Algorithm, CMA) ve CMA tabanlÕ de÷iútirilmiú CMA (Modified CMA, M-CMA) ve normalize edilmiú CMA (Normalized CMA, N-CMA) algoritmalarÕnÕn semboller arasÕ giriúimi (ISI) azaltma ve ortalama karesel hata (MSE) baúarÕmlarÕ incelenmektedir.

2024

Aircraft noise perception is related to several variables that are tangible and objective, such as the number of operations, flight schedules. Other variables, instead, are more subjective, Additionally, this paper highlights the aviation noise problem taken into account a scenario where the airport capacity may duplicate in the next 20 years. This scenario is compounded by the paradigmatic change on environmental awareness that has emerged all over the world, as a result of the changing social and economic preferences, which favors human quality of life and a sustainable growth, in order to preserve resources endowments and quality of life for future generations. Under these circumstances, it can be foresighted that the social change is for the internalization of environmental problems, with the expected increase in the air transport sector costs.

2024, 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

Reverberation degrades speech intelligibility in telecommunications as well as it increases the word error rate in automatic speech recognition tasks. Several dereverberation methods have been proposed recently in order to counter these effects. In the single microphone case, the dereverberation problem is underdetermined and reverberation suppression approaches are preferred. In this paper we propose a novel method for single channel reverberation suppression. Late reverberation is estimated in the time-frequency domain as a sparse linear combination of previous frames. The predictors associated to the model are determined in a Lasso framework and a spectral subtraction filter is designed to produce the enhanced signal. This model does not require any additional information about the room acoustics and it is well suited for real-time applications. The method has state-of-the-art performance in terms of both reverberation suppression and spectral distortion.

2024, Journal of Intelligent Information Systems

A review of available audiovisual speech corpora and a description of a new multimodal corpus of English speech recordings is provided. The new corpus containing 31 hours of recordings was created specifically to assist audiovisual speech recognition systems (AVSR) development. The database related to the corpus includes high-resolution, high-framerate stereoscopic video streams from RGB cameras, depth imaging stream utilizing Time-of-Flight camera accompanied by audio recorded using both: a microphone array and a microphone built in a mobile computer. For the purpose of applications related to AVSR systems training, every utterance was manually labeled, resulting in label files added to the corpus repository. Owing to the inclusion of recordings made in noisy conditions the elaborated corpus can also be used for testing robustness of speech recognition systems in the presence of acoustic background noise. The process of building the corpus, including the recording, labeling and post-processing phases is described in the paper. Results achieved with the developed audiovisual automatic speech recognition (ASR) engine trained and tested with the material contained in the corpus are presented and discussed together with comparative test results employing a state-of-the-art/commercial ASR engine. In order to demonstrate the practical use of the corpus it is made available for the public use.

2023, Journal of Geophysical Research: Atmospheres

Satellite measurements from the infrared (IR) channels of the Advanced Very High Resolution Radiometer (AVHRR)/NOAA have been used to derive many important atmospheric, cloud, and surface parameters for weather prediction, climate modelling, and a variety of environmental studies. Calibration accuracy of the satellite data directly affects accuracies of the derived parameters. So far, very limited attention has been given to the calibration uncertainties of the IR channels. In this study, we analyzed the calibration data of AVHRR radiometers onboard polar orbiting satellites NOAA‐9 to NOAA‐16. We utilized Global Area Coverage (GAC) data, approximately one orbit per month throughout the lifetime of the instruments, available from the NOAA Satellite Active Archive (SAA). AVHRR IR channels 3B, 4, and 5 are calibrated in‐flight. Calibration coefficients are derived from measurements of radiance emitted from an internal calibration target (ICT) and deep‐space (SP). The overall budget of ...

2023, EURASIP Journal on Advances in Signal Processing

We propose a procedure to estimate the model parameters of presented nonlinear Resistance-Capacitance (RC) and the widely used linear Resistance-Inductance-Capacitance (RIC) models of the respiratory system by Maximum Likelihood Estimator (MLE). The measurement noise is assumed to be Generalized Gaussian Distributed (GGD), and the variance and the shape factor of the measurement noise are estimated by MLE and Kurtosis method, respectively. The performance of the MLE algorithm is also demonstrated by the Cramer-Rao Lower Bound (CRLB) with artificially produced respiratory signals. Airway flow, mask pressure, and lung volume are measured from patients with Chronic Obstructive Pulmonary Disease (COPD) under the noninvasive ventilation and from healthy subjects. Simulations show that respiratory signals from healthy subjects are better represented by the RIC model compared to the nonlinear RC model. On the other hand, the Patient group respiratory signals are fitted to the nonlinear RC model with lower measurement noise variance, better converged measurement noise shape factor, and model parameter tracks. Also, it is observed that for the Patient group the shape factor of the measurement noise converges to values between 1 and 2 whereas for the Control group shape factor values are estimated in the super-Gaussian area.

2023, Journal of Photochemistry and Photobiology B: Biology

The ultra-weak photon emission (biophoton) patterns of wheat germination tests under chemical stress (mercury and fluoride solutions) are presented in comparison to respective control groups run simultaneously in two similar, automatic photon-count chambers. Solutions of Hg (EC 50 and EC 100) and NaF (EC 50) were applied at the fourth day, after the first 72 h of imbibition in water, with photon-count experiments in controlled conditions. Seedlings' growth performance were checked by total mass increase as well as root development, and plotted against the respective angular factor of photon-count curve's linear regression. Both Hg and NaF series presented very distinguishable patterns when compared to each respective control groups. Higher counts appear all over the 24 h test for the Hg series and just in the first 6 h for the NaF series.

2023

2023, Speech Communication

In many acoustic conditions, a single-channel recorded speech signal may be severely affected by reverberation and noise, leading to a reduced speech quality and intelligibility. This paper focuses on proposing a novel twostage model scheme by decomposing room impulse responses (RIRs) into two convolution parts for singlechannel speech dereverberation and denoising. Similar as previous methods, the proposed two-stage model uses non-negative approximations of the convolutive transfer function (NeCTF) to simultaneously estimate the magnitude spectrograms of the speech and the RIR. It focuses on iteratively updating model parameters to estimate a less reverberant speech signal and a short RIR at first stage, then the clean speech signal and the other short RIR are estimated by iteratively renewing at the second stage. There are always denosing processing steps existing in both stages to denoise more thoroughly. A straightforward method based on the scheme is built to enhance the speech from the noisy reverberant signal, then two fusion methods inspired by ensemble learning are proposed for speech enhancement. The advantages of our proposed methods are more capable to enhance the speech and more time-saving through decomposing the long RIRs into two shorter ones. Additionally, the optimal estimator is derived based on temporal stacking to utilize speech temporal dynamics. Experiments are performed on two simulated RIRs and a real RIR to compare the performances of the proposed methods with a state-of-the-art method and the results show that the proposed methods have achieved either better or comparable performances in most measures but phone error rate.

2023

This paper describes an algorithm for feature extraction from measurements collected by laser range finder. The features are straight lines and corners present in the environment. The measurements are processed in the sensor coordinate system to identify an invariant parameter for the present straight lines that indicate their position and orientation. A second parameter is needed to determine the slopes of the straight lines as well as the values of the intersection angles between the consecutive lines which can be considered as corners in the case of right angles. A log-Hough transformation is used to find the equations of the straight lines. All the computations are carried out in the sensor coordinate system which leads to a fast and robust algorithm of feature extraction. Practical examples are presented to evaluate the efficiency of the algorithm. Key-Words: -Feature Extraction, Corners and lines, log-Hough transform

2023, Physical Review E

We contrast two sets of conditions that govern the transition in which classical dynamics emerges from the evolution of a quantum system. The first was derived by considering the trajectories seen by an observer (dubbed the "strong" transition) [Bhattacharya et al., Phys. Rev. Lett. 85 4852 (2000)], and the second by considering phase-space densities (the "weak" transition) [Greenbaum et al., Chaos 15, 033302 (2005)]. On the face of it these conditions appear rather different. We show, however, that in the semiclassical regime, in which the action of the system is large compared to , and the measurement noise is small, they both offer an essentially equivalent local picture. Within this regime, the weak conditions dominate while in the opposite regime where the action is not much larger than , the strong conditions dominate.

2023, arXiv (Cornell University)

We examine the radioactive decay of iodine in terms of its Kolmogorov entropy, observing a consistency with the presence of a regime of deterministic chaos in the vacuum dynamics.

2023, ISPRS Journal of Photogrammetry and Remote Sensing

Measurements of the surface thermal infrared (TIR) radiance provides an estimate of the land surface temperature (LST). However, any TIR measurement must be acquired under a certain geometry observation, which may refer to strong directional anisotropies. Although physical radiative transfer models can provide high precision directional brightness temperature simulation, they are too complex for processing large volumes of satellite data. With the objective to compare TIR measures acquired under different viewing angles, the topic of angular normalization issue for retrieved LSTs could be treated based on semi-empirical modelling. In this paper, we consider such category of models to simulate the directional anisotropy of surface brightness temperatures in combination with visible and near-infrared (VNIR) data. In these models, the vegetation fraction and the hot spot effect are depicted by a vegetation index and a brightness factor, respectively. An evaluation of the method is performed with both synthetic and measured datasets. The directional anisotropies that are fitted by this semiempirical model demonstrate good agreement with an extensive synthetic dataset that is generated with the Soil Canopy Observation, Photochemistry and Energy Fluxes (SCOPE) soil-vegetation-atmosphere transfer model. An evaluation using airborne multi-angle TIR data also reveals that this model performs well when predicting BT directional anisotropies, with root mean square errors (RMSEs) of less than 0.31°C over a maize-planted area. Relative to Roujean-Lagouarde (RL) and Vinnikov models using only TIR data, the proposed model offers better performances. In addition, for future use with satellite data, the proposed model using observations at different times and the combination with VNIR BRDF model are also evaluated, and good results are obtained. It yields a promising approach for the angular normalization of LST and mosaics of fine-scale images.

2023, AGU Fall Meeting Abstracts

The far-infrared spectroscopy of the troposphere (FIRST) instrument is a Fourier transform spectrometer developed to measure the Earth's thermal emission spectrum with a particular emphasis on far-infrared (far-IR) wavelengths greater than 15 μm. FIRST was developed under NASA's Instrument Incubator Program to demonstrate technology for providing measurements from 10 to 100 μm (1000 to 100 cm −1) on a single focal plane with a spectral resolution finer than 1 cm −1. Presently no spectrometers in orbit are capable of directly observing the Earth's far-IR spectrum. This fact, coupled with the fundamental importance of the far-IR to Earth's climate system, provided the impetus for the development of FIRST. In this paper the FIRST instrument is described and results of a detailed absolute laboratory calibration are presented. Specific channels in FIRST are shown to be accurate in the far-IR to better than 0.3 K at 270 K scene temperature, 0.5 K at 247 K, and 1 K at 225 K.

2023, 2012 IEEE Spoken Language Technology Workshop (SLT)

Multimodal speech recognition is a promising approach to realize noise robust automatic speech recognition (ASR), and is currently gathering the attention of many researchers. Multimodal ASR utilizes not only audio features, which are sensitive to background noises, but also non-audio features such as lip shapes to achieve noise robustness. Although various methods have been proposed to integrate audiovisual features, there are still continuing discussions on how the vest integration of audio and visual features is realized. Weights of audio and visual features should be decided according to the noise features and levels: in general, larger weights to visual features when the noise level is low and vice versa, but how it can be controlled? In this paper, we propose a method based on piecewise linear transformation in feature integration. In contrast to other feature integration methods, our proposed method can appropriately change the weight depending on a state of an observed noisy feature, which has information both on uttered phonemes and environmental noise. Experiments on noisy speech recognition are conducted following to CENSREC-1-AV, and word error reduction rate around 24% is realized in average as compared to a decision fusion method.

2023, Electronics

The electrocardiogram (ECG) is basic equipment used in the diagnosis of cardiac illness. However, in non-developed countries, most of the population does not have access to medical tests, and many hospitals do not even have these ECGs. On the other hand, the electrical signals generated by the heart and acquired by the ECG have low power and are affected by electromagnetic interference (EMI), mainly produced by the electrical system. Filtering EMI when frequency varies is a challenging task. Within this context, this work aims to produce an easy-to-use low-cost ECG with good electromagnetic disturbances rejection. The proposed noise rejection system is composed of two moving average filters and a phase-locked-loop, namely 2MAV-PLL. The system operates with a low sampling frequency and attenuates the EMI noise present in the ECG signal regardless of the amplitude, obtaining a filtered signal with a 44-dB signal–noise ratio (SNR) between the frequencies of± 10 Hz of the fundamental fr...

2023, Digest of Papers. 2005 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2005.

Two compact SiGe HBT low noise amplifiers for ultra-wideband (UWB) applications are presented. The measured noise figure of the first approach is 2.4dB at 7GHz and below 2.9dB in the UWB bandwidth from 3.1GHz up to 10.6GHz. The circuit delivers 17.3dB peak gain with gain variations of less than 1.6dB within the entire band. The measured input 1-dB compression point at 7GHz is-13.5dBm with 16.6mA total current consumption from a 3.3V supply. The second approach exhibits noise figures between 2.8dB and 3.2dB within the UWB band. Measurements show 23.5dB of gain with 0.6dB variation over the full bandwidth. The measured input 1-dB compression point at 7GHz is-19.5dBm with a 18.2mA bias current at a 3.0V supply. The first and second design occupy a chip size of 0.39mm x 0.38mm and 0.44mm x 0.38 mm, respectively.

2023

Publication in the conference proceedings of EUSIPCO, Florence, Italy, 2006

2023, 2007 IEEE 9th Workshop on Multimedia Signal Processing

We study the effect of uncertain feature measurements and show how classification and learning rules should be adjusted to compensate for it. Our approach is particularly fruitful in multimodal fusion scenarios, such as audiovisual speech recognition, where multiple streams of complementary features whose reliability is time-varying are integrated. For such applications, by taking the measurement noise uncertainty of each feature stream into account, the proposed framework leads to highly adaptive multimodal fusion rules for classification and learning which are widely applicable and easy to implement. We further show that previous multimodal fusion methods relying on stream weights fall under our scheme under certain assumptions; this provides novel insights into their applicability for various tasks and suggests new practical ways for estimating the stream weights adaptively. The potential of our approach is demonstrated in audiovisual speech recognition experiments.

2023

Most Automatic Speech Recognition (ASR) systems only use speech features extracted from the speaker's audio signal. The performance of such audio-only speech recognizers heavily degrades whenever the audio signal is not ideal, for example in environments with heavy acoustic noise. One recent approach to robust speech recognition in such adverse conditions is to also utilize in ASR systems visual speech related features extracted from videos capturing the speaker's face. This approach to robust ASR is inspired from the audiovisual mechanisms also present in human speech recognition. The purpose of this paper is twofold: (1) To make a short introduction to the field of audiovisual speech recognition and highlight the research challenges in the area; and (2) to summarize our recent research in the problem of adaptive audiovisual fusion.

2023, Journal of the Optical Society of America. A, Optics, image science, and vision

In this work we present a model for image formation in optical coherence microscopy. In the spectral domain detection, each wavenumber has a specific coherent transfer function that samples a different part of the object's spatial frequency spectrum. The reconstruction of the tomogram is usually accurate only in a short depth of field. Using numerical simulations based on the developed model, we identified two distinct mechanisms that influence the signal of out-of-focus sample information. Besides the lateral blurring induced through defocusing, an additional axial envelope contributing equally to the signal degradation was found.

2023, Noise and Fluctuations in Photonics, Quantum Optics, and Communications

Broadband services require data rates that can only be achieved by using relatively high spectrum frequencies. At such high frequencies, the DSL (Digital Subscriber Line) signal is more susceptible to external noise sources, such as radio frequency interference and impulsive noise. This paper aims to characterize how the impulsive noise impacts on services and applications for a broadband system using an ADSL2+ loop. The first approach was to use the impulsive noise defined in the standards G.996.1 (Test Procedures for DSL Transceivers) from ITU-T and TR-048 (ADSL Interoperability Test Plan) from DSL Forum. In this approach we have also used a HDSL (High Bit Rate DSL) and white noise disturbers on the line. The impulsive noises c1 and c2 (defined in G.996.1) are injected into the circuit at the CO (Central Office) end and CPE (Customer Premises Equipment) end of the loop simulator. Additionally, it was analyzed the spikes of noise's impact on the ADSL2+ line. In this case, pre-defined models of NEXT (Near-end crosstalk) and white noise are injected on CO and CPE side, simultaneously. Metrics like packet rate, lost packet count, bandwidth, short-term average transfer delay, and errored seconds are used to characterize the DSL loop under the noise impairments.

2023

Many projects analyze application overlay networks on the Internet using packet analysis and network flow data. This is infeasible on many networks: either the volume of data makes packet inspection intractable, or privacy concerns forbid packet capture and require the dissociation of network flows from users' identities. We describe a framework for exploration of usage patterns even under circumstances where the only available data is anonymized flow records. We offer two proofs of concept using data gathered from Internet2. In the first, we uncover distributions and scaling relations in host-to-host networks with implications for capacity planning and application design. In the second, we classify network applications based on properties of their overlay networks, yielding a taxonomy that allows us to identify the functions of unknown applications.

2023, Extreme Physiology & Medicine

Background: The ventilatory compensation point (VCP) is an exercise threshold which has been used in the design of training programs in sports medicine and rehabilitation. We recently demonstrated that changes in the slope of the minute ventilation to heart rate relationship (Δ _ V E =ΔHR) can be utilized for estimation of the VCP during incremental exercise at sea level (SL). We hypothesized that in hypoxic conditions, such as high altitude (HA), VCP can be also reliably estimated by Δ _ V E =ΔHR. Methods: At SL and on immediate ascent to HA (5,050 m), six healthy subjects (42 ± 14 SD years) performed a maximal incremental exercise test on a cycle ergometer; O 2 uptake (_ V O 2), CO 2 output (_ V CO 2), _ V E , and HR were measured breath-by-breath. The Δ _ V E =ΔHR method for VCP estimation was compared to the standard method using the ventilatory equivalent for CO 2 (_ V E = _ V CO 2) and end-tidal PCO 2 (P ET CO 2). The Δ _ V E =ΔHR slope values below (S 1) and above (S 2) VCP were computed by linear regression analysis. Results: A significant difference between S 1 and S 2 was observed, at SL and HA, for both the Δ _ V E =ΔHR and _ V E = _ V CO 2 methods for VCP estimation. A good agreement between the two methods (Δ _ V E =ΔHR vs. _ V E = _ V CO 2) was found for both environmental conditions; the mean difference ± 2 SD of _ V O 2 at VCP (VCP-_ V O 2) was −22 ± 112 ml/ min at SL and 39 ± 81 ml/min at HA. The VCP-_ V O 2 was significantly lower at HA compared to SL; in addition, S 1 and S 2 mean values were significantly higher at HA compared to SL. Conclusion: At HA, VCP may be reliably estimated by the Δ _ V E =ΔHR method.

2023, Journal of Geodesy

Decades of cruise-based exploration have provided excellent snapshots of the structure of mid-ocean ridges and have revealed that accretion is a mixture of steady-state and quantum events. Observatory-type studies are now needed to quantify the temporal evolution of these systems. A multidisciplinary seafloor observatory site is currently being set up at the Lucky Strike volcano, in the axial valley of the slow spreading Mid-Atlantic ridge as a part of the MoMAR (monitoring of the Mid-Atlantic Ridge) initiative.

2023, International Journal of Chemical & Material Sciences

Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic diseases in which there are high blood sugar levels over a prolonged period. If not regulate the glucose level then it will cause the serious damage to heart, kidneys, eyes, and nerves. The pancreas produces insulin to absorb the glucose. In type I diabetes the pancreas does not secrete insulin to compensate this artificial pancreas will be used. The artificial pancreas will mimic the function of pancreas it consists of a sensor, controller and insulin pump. The sensor continuously monitors glucose, the amount of insulin required will be calculated using a controller then injected using insulin pump this is the function of the artificial pancreas. The food we take is converted into glucose. So, meal intake will greatly affect the glucose levels, in this paper a closed loop model is developed based on Bergman's minimal model and meal intake is introduced as a disturbance then the control action is performed using Fuzzy and PID controller using LABVIEW software. So, from this, if the glucose concentration exceeds/decreases, above/below a certain point necessary control action will be taken.

2023, Asian Finance Association (AsianFA) 2013 Conference (Archive)

We propose a reliable new estimator for realized skewness which is robust to microstructure noise at ultra-high frequency level. Asymptotic theory for the new estimator has been de- rived. Simulation example veries its superior performance. We apply the new estimator to tick data of the S&P 500 index for forecasting equity premium in the U.S. market from 1990-2011 and nd that it has signicant forecast-ability both in-sample and out-of-sample. We also show that the new skewness measure plus the variance risk premium provides right decomposition for the skewness risk. We thus provide evidence that realized skewness links to conditional market premium.

2023, THE AIRPORT NOISE PARADOX: DNL DROPS WHILE PROBLEM GROWS

The day-night average sound level (DNL) noise metric was published by the U.S. Environmental Protection Agency in their 1974 Levels Document as the standard metric for all types of community noise impact [1], and was formally adopted by the Federal Aviation Administration (FAA) as their airport noise exposure standard in 1981 [2]. It has served as the predominant noise exposure metric in the United States for a quarter century.
noise exposure metric in the United States for a quarter century

2023, Retrofit Sound Insulation: The Morning After

For more than ten years the United States Federal Aviation Administration (FAA) has sponsored an ongoing program of retrofit noise insulation for noise-impacted residences near airports. Local municipalities or airports administer the programs in accordance with FAA standards, and at no cost to the homeowners. While most programs have achieved the technical objectives, the reaction to the program by the homeowners and by the municipalities has been a mixture of favorable and unfavorable. This paper summarizes the FAA program, and examines the expectations, results and responses of the homeowners for several airport noise insulation projects. Social survey data is presented and specific program issues are identified and discussed. Homeowner attitudes to the retrofit programs are affected by noise reduction performance and by non-acoustical issues. Non-acoustical factors affecting homeowner opinions include homeowner attitudes about the efficacy of the airport, lifestyles, and attitudes regarding the right to a quiet home environment. Several case studies are reviewed and social survey results are examined.

2023, BMC Bioinformatics

Background: We consider the problem of identifying the dynamic interactions in biochemical networks from noisy experimental data. Typically, approaches for solving this problem make use of an estimation algorithm such as the well-known linear Least-Squares (LS) estimation technique. We demonstrate that when time-series measurements are corrupted by white noise and/or drift noise, more accurate and reliable identification of network interactions can be achieved by employing an estimation algorithm known as Constrained Total Least Squares (CTLS). The Total Least Squares (TLS) technique is a generalised least squares method to solve an overdetermined set of equations whose coefficients are noisy. The CTLS is a natural extension of TLS to the case where the noise components of the coefficients are correlated, as is usually the case with timeseries measurements of concentrations and expression profiles in gene networks. Results: The superior performance of the CTLS method in identifying network interactions is demonstrated on three examples: a genetic network containing four genes, a network describing p53 activity and mdm2 messenger RNA interactions, and a recently proposed kinetic model for interleukin (IL)-6 and (IL)-12b messenger RNA expression as a function of ATF3 and NF-κB promoter binding. For the first example, the CTLS significantly reduces the errors in the estimation of the Jacobian for the gene network. For the second, the CTLS reduces the errors from the measurements that are corrupted by white noise and the effect of neglected kinetics. For the third, it allows the correct identification, from noisy data, of the negative regulation of (IL)-6 and (IL)-12b by ATF3. Conclusion: The significant improvements in performance demonstrated by the CTLS method under the wide range of conditions tested here, including different levels and types of measurement noise and different numbers of data points, suggests that its application will enable more accurate and reliable identification and modelling of biochemical networks.

2023, The Journal of the Acoustical Society of America

We have made signi cant progress in automatic speech recognition ASR for well-de ned applications like dictation and medium vocabulary transaction processing tasks in relatively controlled environments. However, for ASR to approach h uman levels of performance and for speech to become a truly pervasive user interface, we need novel, nontraditional approaches that have the potential of yielding dramatic ASR improvements. Visual speech is one such source for making large improvements in high noise environments with the potential of channel and task independence. It is not e ected by the acoustic environment and noise, and it possibly contains the greatest amount of complementary information to the acoustic signal. In this workshop, our goal was to advance the state-of-the-art in ASR by demonstrating the use of visual information in addition to the traditional audio for large vocabulary continuous speech recognition LVCSR. Starting with an appropriate audiovisual database, collected and provided by IBM, we demonstrated for the rst time that LVCSR performance can be improved by the use of visual information in the clean audio case. Speci cally, b y conducting audio lattice rescoring experiments, we showed a 7 relative word error rate WER reduction in that condition. Furthermore, for the harder problem of speech contaminated by s p e e c h babble" noise at 10 dB SNR, we demonstrated that recognition performance can beimproved by 27 in relative WER reduction, compared to an equivalent audio-only recognizer matched to the noise environment. We believe that this paves the way to seriously address the challenge of speech recognition in high noise environments and to potentially achieve human levels of performance. In this report, we detail a number of approaches and experiments conducted during the summer workshop in the areas of visual feature extraction, hidden Markov model based visual-only recognition, and audiovisual information fusion. The later was our main concentration: In the workshop, a numberof feature fusion as well as decision fusion techniques for audiovisual ASR were explored and compared.

2023, Journal of Strength and Conditioning Research

The purpose of this study was to examine the effect of ramp and step incremental cycle ergometer tests on the assessment of the anaerobic threshold (AT) using 3 different computerized regression-based algorithms. Thirteen healthy adults (mean age and body mass [SD] = 23.4 [3.3] years and body mass = 71.7 [11.1] kg) visited the laboratory on separate occasions. Two-way repeated measures analyses of variance with appropriate follow-up procedures were used to analyze the data. The step protocol resulted in greater mean values across algorithms than the ramp protocol for the V _ O 2 (step = 1.7 [0.6] L$min 21 and ramp = 1.5 [0.4] L$min 21) and heart rate (HR) (step = 133 [21] b$min 21 and ramp = 124 [15] b$min 21) at the AT. There were no significant mean differences, however, in power outputs at the AT between the step (115.2 [44.3] W) and the ramp (112.2 [31.2] W) protocols. Furthermore, there were no significant mean differences for V _ O 2 , HR, or power output across protocols among the 3 computerized regression-based algorithms used to estimate the AT. The current findings suggested that the protocol selection, but not the regression-based algorithms can affect the assessment of the V _ O 2 and HR at the AT.