Sampling (signal processing) (Total 605506 Papers Found)

Recent advances in signal processing methodologies have spawned the way for a high-speed home network power-line communication (PLC) system. In this paper, a novel signal processing method based on wavelet packet analysis is proposed to combat the adverse communication environment over power lines. A comparison research between wavelet transform and wavelet packet transform is presented. Since wavelet packet decomposition can provide more precise frequency resolution than wavelet decomposition, ...
Digital cameras have become popular and many people are choosing to take their pictures with digital cameras instead of film cameras. When a digital image is recorded, the camera needs to perform a significant amount of processing to provide the user a viewable image. This processing includes white balance adjustment, gamma correction, compression and more (reference “Color Image Processing Pipeline in Digital Still Cameras” in this issue). A very important part of this image processing chai ...
We present new BSP algorithms for deterministic sorting and rmdomized median finding. We sort n general keys by using a partitioning scheme that achieves the requirements of efficiency (one-optimality) and insensitivity against data skew (the accuracy of the splitting keys depends solely on the step distance, which can be adapted to meet the worstcase requirements of our application). Although we employ sampling in order to realize efficiency, we can give a precise worst-case estimation of the m ...
The landscape scale distributions of adult male click beetles of the species Agriotes lineatus, A. obscurus and A. sputator, and the cranefly Tipula paludosa were studied using traps along transects over 2 years. The transects (0.7–1.7 km with either sex pheromone (Agriotes) or water (T. paludosa) traps at 100 m spacings) were in an area of mixed organic land use. Agriotes lineatus was the most numerous click beetle caught even though its larvae were absent from these fields. Greater trap c ...
We present an adaptive framework for condensation algorithms in the context of human-face tracking. We attack the face tracking problem by making factored sampling more efficient and appearance update more effective. An adaptive affine cascade factored sampling strategy is introduced to sample the parameter space such that coarse face locations are located first, followed by a fine factored sampling with a small number of particles. In addition, the local linearity of an appearance manifold is u ...
[1] We use regionally available digital elevation models and land cover data, calibrated with groundand photo-based landslide inventories, to produce spatially distributed estimates of shallow, translational landslide density (number/unit area). To discern effects of land use, we focus on resolving landslide density relationships with forest cover. We account for topographic variability between sites and landslide detection bias in air photo mapping. Even so, for sites in the Oregon Coast Range, ...
Matrix function approximation is a current focus of worldwide interest and finds application in a variety of areas of applied mathematics and statistics. In this thesis we focus on the approximation of A−α/2b, where A ∈ Rn×n is a large, sparse symmetric positive definite matrix and b ∈ R is a vector. In particular, we will focus on matrix function techniques for sampling from Gaussian Markov random fields in applied statistics and the solution of fractional–in–space partial different ...
The current paper proposes a trajectory optimization approach for navigating a non-holonomic wheeled mobile robot in dynamic environments. The dynamic obstacle's motion is not known and hence is represented by a band of predicted trajectories. The trajectory optimization can account for large number of predicted obstacle trajectories and seeks to avoid each predicted trajectory of every obstacle in the sensing range of the robot. The two primary contributions of the proposed trajectory optimizat ...
This paper presents an approach for optimal path planning on implicitly-defined configuration spaces such as those arising, for instance, when manipulating an object with two arms or with a multifingered hand. In this kind of situations, the kinematic and contact constraints induce configuration spaces that are manifolds embedded in higher dimensional ambient spaces. Existing sampling-based approaches for path planning on manifolds focus on finding a feasible solution, but they do not optimize t ...
We propose a two parameter ratio-product-ratio estimator for estimating a finite population variance based on simple random sampling without replacement. The bias and mean square error of the proposed estimator are obtained to the first degree of approximation. We have derived the conditions for the parameters under which the proposed estimator has smaller mean square error than the sample variance, ratio and product estimators. We carry out an application showing that the proposed estimator out ...
A new method to address constrained robust model predictive control for systems with polytopic description is proposed. Inheriting from an earlier method, we split the infinite-horizon control moves into a set of free control moves over a fixed horizon and a state feedback law in the terminal region, all on-line optimized. Then, the basic idea is to utilize, at each sampling instant, a fixed number of free control moves to drive (implicitly) the terminal state into a terminal constraint set chan ...
Gaps in time series can produce spurious features in power spectrum estimates. These artifacts can be suppressed by averaging spectrum estimates obtained by first windowing the time series with a collection of orthogonal tapers. Such “multitaper” methods have been used for data without gaps since the early 1980s and for more general sampling schemes since the late 1980s. We introduce three families of tapers for time series with gaps. Two of the families solve optimization problems. They min ...
To evaluate the influence of human activities on ecosystem respiration (CO2) and CH4 fluxes and determine the seasonal and spatial variations, we measured CO2 and CH4 fluxes at four sampling sites (west side of the seawall, WSS; oilfield, OF; Spartina alterniflora coastal marsh, SCM; aquaculture pond, ACP) in the Yellow River estuary from June to December in 2013. Both CO2 and CH4 fluxes showed seasonal and spatial variations in the Yellow River estuary. The average CO2 fluxes from WSS, OF, SCM ...
Digital regulators for continuous plants are designed today by means of conventional <i>z</i>-transfer function methods. With these <i>z</i>-transfer functions the value of the system output <i>y</i>(<i>t</i>) can be learned only at instants spaced <i>T</i> seconds apart, where <i>T</i> is the sampling period. A technique is proposed where the value of <i>y</i>(<i>t</i>) can be learned at instants spa ...
This paper is devoted to theoretic algorithms development and experimental research of automatic target detection of acoustic signals, especially for boats generated signals. In this paper, an observation space is created by sampling and dividing input analog acoustic signal into multiple frames and each frame is transformed into frequency domain. In the created observation space, a median constant false alarm rate (MCFAR) and post detection integration algorithms have been proposed for an effec ...
Conventional orthogonal signal-generation methods for single-phase grid suffer from long response time, approximation errors, and/or noise amplification. To remedy this problem, a novel orthogonal signal-generation algorithm, which is characterized by remarkable response speed, high accuracy, noise immunity, and easy implementation, is developed in this paper. The developed algorithm can precisely calculate the orthogonal signal within about 2.5 ms when the amplitude/phase of the grid signal cha ...
To cater to the demand for ever increasing Internet traffic, on-off keying over multi-mode fiber is expected to be replaced with coherent signaling over single mode fiber in short-reach optical interconnects. One of the key challenges faced at the receiver-end is the recovery of the frequency and phase of the transmitter laser. We propose a novel frequency detector that uses sine-cosine sampling method which can be used in a carrier phase recovery and compensation loop. System level simulations ...
This paper proposes a new blind adaptive MLSE equalizer for frequency selective mobile radio channels. The proposed equalizer performs channel estimation for each survivor path of the Viterbi algorithm (VA), and restricts the number of symbol candidates for the channel estimation in order to reduce prohibitive complexity. In such channel estimation, autocorrelation matrices of the symbol candidates are likely to become singular, which increases the estimation error. To cope with the singularity, ...
Low-cost sensors for simultaneous localisation and mapping (SLAM) on robotic platforms (e.g. miniature sonar or radar) are susceptible to false and missed detections. This paper presents an occupancy-grid algorithm for SLAM which deals with this type of imperfect sensor measurements using the random finite set theoretical framework. The solution is formulated as a Rao-Blackwellised particle filter, where the robot pose is estimated using the sequential Monte Carlo method, while the map (occupanc ...
We report a high-speed inverter circuit based on novel enhancement-mode InP metal-insulator-semiconductor field-effect transistors. The devices exhibit an extrinsic transconductance as high as 320 mS/mm at room temperature. Utilizing electro-optic sampling we have measured the propagation delay of the field-effect transistors to be as short as 15 ps/stage at room temperature. These are the highest transconductance and the shortest propagation delay measured with a field-effect transistor on an I ...
Adaptive antennas are recognized as a means of increasing the performance of communications systems. However, practical realization of such systems relies on suitable calibration of distortion effects caused by the circuitry and antenna structures. This work presents a detailed analysis of the classes of distortion that degrade the performance of adaptive antennas. This uses the results of an adaptive antenna testbed employing an eight-element circular array to illustrate the impact of temperatu ...
The photon upconversion phenomenon was suggested in the past as a potential process to enhance the efficiency of photovoltaic cell. The two most accepted processes responsible of this phenomenon in several host materials like fluoride are the Ground State Excitation (GSA) and Energy Transfer (ETU). In this work, we present the synthesis and preparation of Tin dioxide (SnO<inf>2</inf>) co-doped Er<sup>3+</sup>/Yb<sup>3+</sup> trivalent rare earth employed in ph ...
This article develops an approach that extends the methods that simulate individual pathways and describe and explain the population distribution of individual pathways. Conventional microsimulation often bases on static models, ignores its randomness, and fails to provide the sampling distribution of simulated individual pathways. Our approach uses dynamic modeling, corrects for the randomness of microsimulation, and provides sampling distribution of simulated individual pathways. Conventional ...
This paper uses send-on-delta (SoD) strategies to reduce the sampling error instead of reducing the amount of sent messages. For this purpose, we present a procedure that selects an appropriate delta value for a given mean transmission rate. Signals are then sampled using the send-on-delta strategy with the selected delta value. The amount of sent messages will be higher in time intervals where the signal changes fast, and lower in time intervals where the signal changes slow, but maintaining th ...
A bandpass /spl Sigma//spl Delta/ modulator is demonstrated to operate at a very high sampling rate of 240 MS/s by employing a proposed double-sampling switched-capacitor biquadratic filter architecture, which processes with a fast-settling feature. Implemented in a standard 0.35-/spl mu/m CMOS process, the modulator achieves a peak SNDR of 72 dB, 55 dB and 52 dB at a bandwidth of 200 kHz, 1 MHz and 1.25 MHz for GSM, Bluetooth and CDMA2000 applications respectively while dissipating 37 mW and oc ...
THE STRINGENT REQUIREMENTS imposed on implantable telemetry systems often preclude continuous operation . In such cases, the operating life of battery powered implants must be extended by the use of a radio-controlled power switch, or command receiver, to disconnect the battery when physiological data are not needed. Micropower monolithic circuits for an implantable command receiver have been demonstrated, but their use has been limited by short range and availability problems . Continuous micro ...
INTRODUCTION Estimation of genetic parameters is one of the basic tasks in quantitative genetics. As recording schemes become more sophisticated and breeding objectives more detailed, the number of traits of interest is increasing continually. This necessitates multivariate analyses considering more than just a few traits simultaneously. Fortunately, we are at a stage were advances in modelling, computational algorithms and the corresponding software for estimation, paired with modern day comput ...
A power-spectrum-analysis-based signal processing system was developed for vortex flowmeters. This system consists of a digital signal processor (DSP), an analog input part, an output part, a keyboard input circuit, a guard circuit, a serial communication interface, and software. The sensor output signals are processed digitally using the power spectrum analysis based on fast Fourier transform, and the signal frequency reflecting the flow rate is calculated. With the change of sampling frequency ...
This paper presents an algorithm of modifying free-formed NURBS curve/surface for offsetting without local self-intersecting. The method consists of (1) sampling a number of points from a progenitor curve/surface based on second derivatives; (2) checking the curvature or maximum curvature of the progenitor curve/surface at the sampled points; (3) inserting corresponding knots of sampled points; (4) repositioning control points till the curvature/maximum curvature of the curve/surface everywhere ...
We describe a fast sampling algorithm for generating uniformly-distributed point patterns with good blue noise characteristics. The method, based on constrained farthest point optimization, is provably optimal and may be easily parallelized, resulting in an algorithm whose performance/quality tradeoff is superior to other state-of-theart approaches. ...
Warren Mitofsky and Joseph Waksberg were two of the most influential researchers in telephone surveys and survey research methods. Their development of the Mitofsky–Waksberg method for random digit dialing sampling revolutionized telephone sampling and surveys. Jointly and separately, Waksberg and Mitofsky were instrumental in the development of many innovative methods and applications. This article reviews some of their contributions and discusses how their approaches to these problems may be ...
Cardiac arrhythmia refers to any abnormal electrical activity in the heart that causes irregular heartbeat. Under clinical settings, the arrhythmias can be monitored non-invasively using the electrocardiogram (ECG). Although reliable, the method is still prone to error due to its dependence on visual interpretation. Further, ECG data is enormous in dimension and increases as the data sampling rate increases. The increase in ECG sampling rate puts a limitation on processing of ECG data for analys ...
A measurement system of dynamic resistance of vehicle electronic line connector based on PXI Express(PXIe) technology was established. The system hardware was composed of PXIe box, PXIe high speed digitalizer, PXIe arbitrary waveform generator, high precision currency source and so forth. And the system operating interface was designed by LabVIEW, the virtual instrumentation software, with direct test results displayed on screen. This system can automatically measure dynamic impedance avoiding l ...
As the size and complexity of models grow, there is a need to count on novel mechanisms and tools for transforming them. This is required, e.g., when model transformations need to provide target models without having access to the complete source models or in really short time—as it happens, e.g., with streaming models—or with very large models for which the transformation algorithms become too slow to be of practical use if the complete population of a model is investigated. In this paper w ...
This study aims to investigate factors affecting knowledge sharing among librarians working in public libraries of Fars Province, Iran. The research uses a survey method. Using stratified random sampling technique, 180 librarians were selected as a sample. The data collection instrument is a questionnaire with an acceptable reliability. Data analysis was accomplished using Lisrel Full Version 8.7. The study findings revealed that education and consultation programs improve librarians’ performa ...
This project aims to investigate the quality of ASCAT measurements as well as their use for oceanographic purposes. The accuracy of ASCAT retrievals will be mainly based on the use of collocated data from moored buoys, numerical weather prediction models, and satellites. The resulting collocated data will be used to explore the accuracy of the geophysical model function which relates the backscatter coefficients to surface wind vectors, as well as to assess the quality of ASCAT vector winds at g ...
Recent guidance on environmental modeling and global land-cover validation stresses the need for a probability-based design. Additionally, spatial balance has also been recommended as it ensures more efficient sampling, which is particularly relevant for understanding land use change. In this paper I describe a global sample design and database called the Global Grid (GG) that has both of these statistical characteristics, as well as being flexible, multi-scale, and globally comprehensive. The G ...
The sampling of spectrally sparse high-bandwidth signals below the Nyquist rate is of importance in many applications. In order to keep the front-end analog-to-digital converter sampling rate low, there has been a lot of recent interest in the literature to develop efficient and practical architectures for low-rate sampling and recovery of spectrally sparse signals. Our main contribution is a simple, implementation-friendly front-end sampling-architecture and a computationally efficient back-end ...
The key parameters that determine channel performance in telecommunications are bit error rate, Q-factor, signal to noise ratio and noise factor. Channel performance depends on signal susceptibility to attenuation, noise, jitter and other interferences in the propagating medium. Typical non-service affecting methods that estimate the channel performance rely on error detecting and correcting codes that have limited error detection capability and require relatively long time. In this paper, we re ...
Introduction: 3D MR spectroscopic imaging (3D MRSI) is a powerful tool for diagnosis of brain tumors but long acquisition times in the order of 20-30 minutes causes patient discomfort and motion artifacts. In recent years, several pulse sequence developments proposing different trajectories in k-space such as elliptical sampling (sampling the central elliptical portion of k-space) or echo-planar imaging have been proposed in the literature to reduce the scan time. Alternatively, sensitivity enco ...
The 1940 and 1950 Public Use Sample Project is the creation of 1/100 household samples from the 1940 and 1950 Censuses of Population. The data source for the samples is the microfilmed original Population Schedules which contain the census enumerator's recording of household information. The procedure to sample the universe of household listings and transcribe the sample households' data is described in the paper. A pretest of the 1940 Public Use Sample included a comparison of three methods of ...
A new semiparametric estimator for an empirical asset pricing model with general nonparametric risk-return tradeoff and a GARCH process for the underlying volatility is introduced. The estimator does not rely on any initial parametric estimator of the conditional mean function, and this feature facilitates the derivation of asymptotic theory under possible nonlinearity of unspecified form of the risk-return tradeoff. Besides the nonlinear GARCH-in-mean effect, our specification accommodates exog ...
The creation of plausible human animation remains a perennial problem in computer graphics. To construct long animations it is common to stitch together a sequence of motions from a motion database. Typically, this is done in two stages: planning a route and then sampling motions from the database to follow that route. We introduce an environment-aware motion sampling technique that combines the planning and sampling stages. Our observation is that in the traditional approach the route generated ...
The authors report the revision for a course entitled Discrete Data Systems which is a blend of classical and modern digital control, and digital filtering. This revision reflects computing resources now available and as a result no longer are low order system problems assigned. The authors have incorporated symbolic computing in several appropriate places where it can increase understanding and yield error-free algebraic manipulations. In most exercises, the computing is of the numerical type u ...
In this paper the geometric process is used for the analysis of accelerated life testing for MarshallOlkin Extended Exponential (MOEE) distribution using Type II censored data. Assuming that the lifetimes under increasing stress levels form a geometric process, The parameters are estimated by using the maximum likelihood method and the original parameters instead of the developing inference for the parameters of the log linear link function are used. The asymptotic interval estimates of the para ...
In this paper, the containment control problem of continuous-time double-integrator multi-agent systems is investigated. An aperiodic sampled-data based protocol is induced by using neighboring information with uncertainly time-varying sampling intervals. With the obtained protocol and properties of Laplacian matrix, the containment control problem of continuous-time multi-agent systems is equivalently transformed into a stability problem of discrete-time systems. By fixing a sampling length in ...
Based on the impulse radar and the spread-spectrum (SS) radar, the through-wall imaging with three stationary targets or a moving target in a room are obtained, respectively, and compared in this paper. We then analyze the influences of different analog-to-digital converters (ADCs) and noise levels on imaging quality. Results show that the SS radar has a great advantage over the impulse radar in some ways, such as covert waveform, engineering realization, excellent anti-noise performance, and ac ...
FALCON airborne gravity gradient data can be converted to vertical gravity via direct integration techniques (Gunn, 1975) or equivalent source methods (Dampney, 1969), and hence compared with conventional gravimetry data. Either conversion process amplifies long wavelength features from the gravity gradient data and therefore makes regional scale features vulnerable to distortion. Recent FALCON surveys over areas with pre-existing ground gravity have allowed proper assessment of when conversion ...
Accuracy is increasingly recognized as an important dimension in geospatial information and analyses. A strategy well suited for map users who usually have limited information about map lineages is proposed for location-specific characterization of accuracy in land cover change maps. Logistic regression is used to predict the probabilities of correct change categorization based on local patterns of map classes in the focal three by three pixel neighborhood centered at individual pixels being ana ...