Articles de revues : « Distributed estimate »

1

Chiun-Chieh, H. « Distributed task assignment using critical path estimate ». Information Sciences 74, n^o 3 (novembre 1993) : 191–212. http://dx.doi.org/10.1016/0020-0255(93)90095-4.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

2

Chong, Sang C., et Karla K. Evans. « Distributed versus focused attention (count vs estimate) ». Wiley Interdisciplinary Reviews : Cognitive Science 2, n^o 6 (23 décembre 2010) : 634–38. http://dx.doi.org/10.1002/wcs.136.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

3

Zhang, Qiaoling, Zhe Chen et Fuliang Yin. « Global Coherence Field and Distributed Particle Filter-Based Speaker Tracking in Distributed Microphone Networks ». Journal of Computational Acoustics 23, n^o 03 (25 juin 2015) : 1550010. http://dx.doi.org/10.1142/s0218396x15500101.

Texte intégral

Résumé :

Based on the combination of global coherence field (GCF) and distributed particle filter (DPF) a speaker tracking method is proposed for distributed microphone networks in this paper. In the distributed microphone network, each node comprises a microphone pair, and its generalized cross-correlation (GCC) function is estimated. Based on the average over all local GCC observations, a global coherence field-based pseudo-likelihood (GCF-PL) function is developed as the likelihood for a DPF. In the proposed method, all nodes share an identical particle set, and each node performs local particle filtering simultaneously. In the local particle filter, the likelihood GCF-PL for each particle weight is computed with an average consensus algorithm. With an identical particle set and the consistent estimate of GCF-PL for each particle weight, all individual nodes possess a common particle presentation for the global posterior of the speaker state, which is utilized by each node for an estimated global speaker position. Employing the GCF-PL as the likelihood for DPF, no assumption is required about the independence of nodes observations as well as observation noise statistics. Additionally, only local information exchange occurs among neighboring nodes; and finally each node has a global estimate of the speaker position. Simulation results demonstrate the validity of the proposed method.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Berrahmoune, Larbi. « Stabilization and decay estimate for distributed bilinear systems ». Systems & ; Control Letters 36, n^o 3 (mars 1999) : 167–71. http://dx.doi.org/10.1016/s0167-6911(98)00065-6.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

5

Li, Wenling, Yingmin Jia et Junping Du. « Distributed extended Kalman filter with nonlinear consensus estimate ». Journal of the Franklin Institute 354, n^o 17 (novembre 2017) : 7983–95. http://dx.doi.org/10.1016/j.jfranklin.2017.09.033.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

6

Bako, Sunday Samuel, Mohd Bakri Adam et Anwar Fitrianto. « Impact of Dependence on Parameter Estimates of Autoregressive Process with Gumbel Distributed Innovation ». MATEMATIKA 34, n^o 2 (2 décembre 2018) : 365–80. http://dx.doi.org/10.11113/matematika.v34.n2.941.

Texte intégral

Résumé :

Recent studies have shown that independent identical distributed Gaussian random variables is not suitable for modelling extreme values observed during extremal events. However, many real life data on extreme values are dependent and stationary rather than the conventional independent identically distributed data. We propose a stationary autoregressive (AR) process with Gumbel distributed innovation and characterise the short-term dependence among maxima of an (AR) process over a range of sample sizes with varying degrees of dependence. We estimate the maximum likelihood of the parameters of the Gumbel AR process and its residuals, and evaluate the performance of the parameter estimates. The AR process is fitted to the Gumbel-generalised Pareto (GPD) distribution and we evaluate the performance of the parameter estimates fitted to the cluster maxima and the original series. Ignoring the effect of dependence leads to overestimation of the location parameter of the Gumbel-AR (1) process. The estimate of the location parameter of the AR process using the residuals gives a better estimate. Estimate of the scale parameter perform marginally better for the original series than the residual estimate. The degree of clustering increases as dependence is enhance for the AR process. The Gumbel-AR(1) fitted to the Gumbel-GPD shows that the estimates of the scale and shape parameters fitted to the cluster maxima perform better as sample size increases, however, ignoring the effect of dependence lead to an underestimation of the parameter estimates of the scale parameter. The shape parameter of the original series gives a superior estimate compare to the threshold excesses fitted to the Gumbel-GPD.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Duda, Zdzisław. « Hierarchical filtration for distributed linear multisensor systems ». Archives of Control Sciences 22, n^o 4 (1 décembre 2012) : 507–18. http://dx.doi.org/10.2478/v10170-011-0038-7.

Texte intégral

Résumé :

In the paper two filtration algorithms for distributed multisensor system are presented. The first one is derived for a linear dynamical system composed of local subsystems described by local state equations. Local estimates are sent to a central station to be fused and formed an optimal global estimate. The second algorithm is derived for a system observed by local nodes that determine estimates of the whole system using local information and periodically aggregated information from other nodes. Periodically local estimates are sent to the central station to be fused. Owing to this a reduced communication can be achieved

Styles APA, Harvard, Vancouver, ISO, etc.

8

Lee, Jongmin, Cihan Tepedelenlioglu, Andreas Spanias et Gowtham Muniraju. « Distributed Quantiles Estimation of Sensor Network Measurements ». International Journal of Smart Security Technologies 7, n^o 2 (juillet 2020) : 38–61. http://dx.doi.org/10.4018/ijsst.2020070103.

Texte intégral

Résumé :

A quantile is a value below which random draws from a distribution falls with a given probability. In a centralized setting where the cumulative distribution function (CDF) is unknown, empirical CDF can be used to estimate quantiles after data aggregation. In a distributed sensor network, it is challenging to estimate quantiles, as each sensor observes local measurement data with limited storage and transmission power, which makes it difficult to obtain the global ECDF. This paper proposes consensus-based quantile estimation for such networks, even when communication links are corrupted by independent random noise. The state-values are recursively updated with two steps: a local update based on measurement data and current state and averaging updated states with local nodes. The estimated state sequence is shown to be asymptotically unbiased and converges toward the sample quantile in the mean-square sense. Applications on the distributed estimation of trimmed mean; computation of median, maximum, or minimum values; and identification of outliers through simulation are also provided.

Styles APA, Harvard, Vancouver, ISO, etc.

9

des Tombe, Bas, Bart Schilperoort et Mark Bakker. « Estimation of Temperature and Associated Uncertainty from Fiber-Optic Raman-Spectrum Distributed Temperature Sensing ». Sensors 20, n^o 8 (15 avril 2020) : 2235. http://dx.doi.org/10.3390/s20082235.

Texte intégral

Résumé :

Distributed temperature sensing (DTS) systems can be used to estimate the temperature along optic fibers of several kilometers at a sub-meter interval. DTS systems function by shooting laser pulses through a fiber and measuring its backscatter intensity at two distinct wavelengths in the Raman spectrum. The scattering-loss coefficients for these wavelengths are temperature-dependent, so that the temperature along the fiber can be estimated using calibration to fiber sections with a known temperature. A new calibration approach is developed that allows for an estimate of the uncertainty of the estimated temperature, which varies along the fiber and with time. The uncertainty is a result of the noise from the detectors and the uncertainty in the calibrated parameters that relate the backscatter intensity to temperature. Estimation of the confidence interval of the temperature requires an estimate of the distribution of the noise from the detectors and an estimate of the multi-variate distribution of the parameters. Both distributions are propagated with Monte Carlo sampling to approximate the probability density function of the estimated temperature, which is different at each point along the fiber and varies over time. Various summarizing statistics are computed from the approximate probability density function, such as the confidence intervals and the standard uncertainty (the estimated standard deviation) of the estimated temperature. An example is presented to demonstrate the approach and to assess the reasonableness of the estimated confidence intervals. The approach is implemented in the open-source Python package “dtscalibration”.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Ouzahra, M., A. Tsouli et A. Boutoulout. « Stabilisation and polynomial decay estimate for distributed semilinear systems ». International Journal of Control 85, n^o 4 (avril 2012) : 451–56. http://dx.doi.org/10.1080/00207179.2012.656144.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

11

Xiao, Ligang, Daowen Qiu, Le Luo et Paulo Mateus. « Distributed Shor's algorithm ». Quantum Information and Computation 23, n^o 1&2 (janvier 2023) : 27–44. http://dx.doi.org/10.26421/qic23.1-2-3.

Texte intégral

Résumé :

Shor's algorithm is one of the most important quantum algorithm proposed by Peter Shor [Proceedings of the 35th Annual Symposium on Foundations of Computer Science, 1994, pp. 124--134]. Shor's algorithm can factor a large integer with certain probability and costs polynomial time in the length of the input integer. The key step of Shor's algorithm is the order-finding algorithm, the quantum part of which is to estimate $s/r$, where $r$ is the ``order" and $s$ is some natural number that less than $r$. {{Shor's algorithm requires lots of qubits and a deep circuit depth, which is unaffordable for current physical devices.}} In this paper, to reduce the number of qubits required and circuit depth, we propose a quantum-classical hybrid distributed order-finding algorithm for Shor's algorithm, which combines the advantages of both quantum processing and classical processing. {{ In our distributed order-finding algorithm, we use two quantum computers with the ability of quantum teleportation separately to estimate partial bits of $s/r$.}} The measuring results will be processed through a classical algorithm to ensure the accuracy of the results. Compared with the traditional Shor's algorithm that uses multiple control qubits, our algorithm reduces nearly $L/2$ qubits for factoring an $L$-bit integer and reduces the circuit depth of each computer.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Duda, Zdzisław. « Fusion Kalman filtration for distributed multisensor systems ». Archives of Control Sciences 24, n^o 1 (1 mars 2014) : 53–65. http://dx.doi.org/10.2478/acsc-2014-0004.

Texte intégral

Résumé :

Abstract In the paper, fusion state hierarchical filtration for a multisensor system is considered. An optimal global Kalman filter is realized by a central node in the information form. The state estimate depends on local information that should be sent by local nodes. Two information structures are considered in the paper. In the first case local estimates are based on the local measurement information. It leads to distributed Kalman filter fusion that is well known in a literature. In the second case local node has additionally global information of the system with one step delay. A synthesis of local filters is presented. An advantage of this structure is discussed.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Turchin, Peter, Thomas Currie, Christina Collins, Jill Levine, Oluwole Oyebamiji, Neil R. Edwards, Philip B. Holden et al. « An integrative approach to estimating productivity in past societies using Seshat : Global History Databank ». Holocene 31, n^o 6 (22 février 2021) : 1055–65. http://dx.doi.org/10.1177/0959683621994644.

Texte intégral

Résumé :

This article reports the results of a collaborative effort to estimate agricultural productivities in past societies using Seshat: Global History Databank. We focus on 30 Natural Geographic Areas (NGAs) distributed over 10 major world regions (Europe, Africa, Southwest Asia, South Asia, Southeast Asia, East Asia, Central Eurasia, North America, South America, and Oceania). The conceptual framework that we use to obtain these estimates combines the influences of the production technologies (and how they change with time), climate change, and effects of artificial selection into a Relative Yield Coefficient, indicating how agricultural productivity changed over time in each NGA between the Neolithic and the 20th century. We then use estimates of historical yield in each NGA to translate the Relative Yield Coefficient into an Estimated Yield (tonnes per hectare per year) trajectory. We tested the proposed methodology in two ways. For eight NGAs, in which we had more than one historical yield estimate, we used the earliest estimate to anchor the trajectory and compared the ensuing trajectory to the remaining estimates. We also compared the end points of the estimated NGA trajectories to the earliest (the 1960s decade) FAO data on crop productivities in the modern countries encompassing Seshat NGAs. We discuss the benefits of this methodology over previous efforts to estimate agricultural productivities in world history.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Meziou, Amine, Zurwa Khan, Taoufik Wassar, Matthew A. Franchek, Reza Tafreshi et Karolos Grigoriadis. « Dynamic Modeling of Two-Phase Gas/Liquid Flow in Pipelines ». SPE Journal 24, n^o 05 (22 avril 2019) : 2239–63. http://dx.doi.org/10.2118/194213-pa.

Texte intégral

Résumé :

Summary Presented is a reduced–order thermal fluid dynamic model for gas/liquid two–phase flow in pipelines. Specifically, a two–phase–flow thermal model is coupled with a two–phase–flow hydraulics model to estimate the gas and liquid properties at each pressure and temperature condition. The proposed thermal model estimates the heat–transfer coefficient for different flow patterns observed in two–phase flow. For distributed flows, where the two phases are well–mixed, a weight–based averaging is used to estimate the equivalent fluid thermal properties and the overall heat–transfer coefficient. Conversely, for segregated flows, where the two phases are separated by a distinct interface, the overall heat–transfer coefficient is dependent on the liquid holdup and pressure drop estimated by the fluid model. Intermittent flows are considered as a combination of distributed and segregated flow. The integrated model is developed by dividing the pipeline into segments. Equivalent fluid properties are identified for each segment to schedule the coefficients of a modal approximation of the transient single–phase–flow pipeline–distributed–parameter model to obtain dynamic pressure and flow rate, which are used to estimate the transient temperature response. The resulting model enables a computationally efficient estimation of the pipeline–mixture pressure, temperature, two–phase–flow pattern, and liquid holdup. Such a model has utility for flow–assurance studies and real–time flow–condition monitoring. A sensitivity analysis is presented to estimate the effect of model parameters on the pipeline–mixture dynamic response. The model predictions of mixture pressure and temperature are compared with an experimental data set and OLGA (2014) simulations to assess model accuracy.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Farahmand, K., et A. Grigorash. « Extrema of random algebraic polynomials with non-identically distributed normal coefficients ». Journal of the Australian Mathematical Society 70, n^o 2 (avril 2001) : 225–34. http://dx.doi.org/10.1017/s1446788700002627.

Texte intégral

Résumé :

AbstractAn asymptotic estimate is derived for the expected number of extrema of a polynomial whose independent normal coefficients possess non-equal non-zero mean values. A result is presented that generalizes in terms of normal processes the analytical device used for construction of similar asymptotic estimates for random polynomials with normal coefficients.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Chu, Tianpeng, Guoqing Qi, Yinya Li et Andong Sheng. « Distributed Asynchronous Fusion Algorithm for Sensor Networks with Packet Losses ». Discrete Dynamics in Nature and Society 2014 (2014) : 1–10. http://dx.doi.org/10.1155/2014/957439.

Texte intégral

Résumé :

This paper is concerned with the problem of distributed estimation fusion over peer-to-peer asynchronous sensor networks with random packet dropouts. A distributed asynchronous fusion algorithm is proposed via the covariance intersection method. First, local estimator is developed in an optimal batch fashion by constructing augmented measurement equations. Then the fusion estimator is designed to fuse local estimates in the neighborhood. Both local estimator and fusion estimator are developed by taking into account the random packet losses. The presented estimation method improves local estimates and reduces the estimate disagreement. Simulation results validate the effectiveness of the proposed distributed asynchronous fusion algorithm.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Yu, Yi, et Haiquan Zhao. « Incremental M ‐estimate‐based least‐mean algorithm over distributed network ». Electronics Letters 52, n^o 14 (juillet 2016) : 1270–72. http://dx.doi.org/10.1049/el.2016.1190.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

18

MING, Yang-yang, Bo YANG, Zi-Yi QUAN et Ai-dong MEN. « Rate estimate for regular LDPCA codec in distributed video coding ». Journal of China Universities of Posts and Telecommunications 19, n^o 1 (février 2012) : 50–54. http://dx.doi.org/10.1016/s1005-8885(11)60227-6.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

19

Senov, Alexander A. « Improving Distributed Stochastic Gradient Descent Estimate via Loss Function Approximation ». IFAC-PapersOnLine 48, n^o 25 (2015) : 292–97. http://dx.doi.org/10.1016/j.ifacol.2015.11.103.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

20

Methot, Richard D., et Ian G. Taylor. « Adjusting for bias due to variability of estimated recruitments in fishery assessment models ». Canadian Journal of Fisheries and Aquatic Sciences 68, n^o 10 (octobre 2011) : 1744–60. http://dx.doi.org/10.1139/f2011-092.

Texte intégral

Résumé :

Integrated analysis models provide a tool to estimate fish abundance, recruitment, and fishing mortality from a wide variety of data. The flexibility of integrated analysis models allows them to be applied over extended time periods spanning historical decades with little information from which to estimate the annual signal of recruitment variability to modern periods in which more information about recruitment variability exists. Across this range of data availability, the estimation process must assure that the estimated log-normally distributed recruitments are mean unbiased to assure mean unbiased biomass estimates. Here we show how the estimation method implemented in the integrated analysis model, Stock Synthesis, achieves this unbiased characteristic in a penalized likelihood approach that is comparable to the results from Markov chain Monte Carlo. The total variability in recruitment is decomposed into variability among annual recruitment estimates based on information in the data and a residual variability. Because data are never perfectly informative, we show that estimated recruitment variability will always be less than the true variability among recruitments and that the method implemented here can be used to iteratively estimate the true variability among recruitments.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Tanveer, Muhammad Hassan, Antony Thomas, Waqar Ahmed et Hongxiao Zhu. « Estimate the Unknown Environment with Biosonar Echoes—A Simulation Study ». Sensors 21, n^o 12 (18 juin 2021) : 4186. http://dx.doi.org/10.3390/s21124186.

Texte intégral

Résumé :

Unmanned aerial vehicles (UAVs) have shown great potential in various applications such as surveillance, search and rescue. To perform safe and efficient navigation, it is vitally important for a UAV to evaluate the environment accurately and promptly. In this work, we present a simulation study for the estimation of foliage distribution as a UAV equipped with biosonar navigates through a forest. Based on a simulated forest environment, foliage echoes are generated by using a bat-inspired bisonar simulator. These biosonar echoes are then used to estimate the spatial distribution of both sparsely and densely distributed tree leaves. While a simple batch processing method is able to estimate sparsely distributed leaf locations well, a wavelet scattering technique coupled with a support vector machine (SVM) classifier is shown to be effective to estimate densely distributed leaves. Our approach is validated by using multiple setups of leaf distributions in the simulated forest environment. Ninety-seven percent accuracy is obtained while estimating thickly distributed foliage.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Veshkurtsev, Yu M., et D. A. Titov. « Determination of probabilistic characteristics of random values of estimates of the Lyapunov function when describing a physical process ». Metrologiya, n^o 4 (15 décembre 2021) : 53–67. http://dx.doi.org/10.32446/0132-4713.2021-4-53-67.

Texte intégral

Résumé :

The applied application of the Lyapunov characteristic function is determined by the properties of its estimates. Probabilistic characteristics of estimates of the Lyapunov characteristic function are described for the first time. The probabilistic characteristics of random values of estimates of the Lyapunov function are empirically estimated using statistical methods. The Matlab package has developed a model of a special device for obtaining estimates of the characteristic function by a direct method. A quasi-deterministic signal is fed to the input of the model, the instantaneous values of which are distributed according to the arcsine law, and an array of values of estimates of the Lyapunov function is obtained at the output, which is used to estimate the probabilistic characteristics of these estimates. Statistical estimation was performed by an indirect method. It is established that the values of the estimates of the Lyapunov characteristic function are distributed according to the normal law. The results of the research will be useful in engineering calculations, for example, when detecting message transmission errors in modems with a modulated characteristic function.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Li, H. G., H. T. Schreuder et C. T. Scott. « Combining estimates that are both in error subject to marginal constraints ». Canadian Journal of Forest Research 20, n^o 10 (1 octobre 1990) : 1675–79. http://dx.doi.org/10.1139/x90-221.

Texte intégral

Résumé :

Outside estimates with measures of reliability can be combined with existing tabular estimates of resource statistics to produce new, more precise estimates. But cell estimates do not sum to the original marginal or overall totals when this is done. A method is given to adjust the unchanged cell values to maintain additivity. Classical and bootstrap variance estimators are given for the n × 2 case of combining a cell proportion with an outside estimate assumed to be binomially distributed under fixed marginal constraints, and for the n × m case of combining a cell proportion with a binomially distributed outside estimate under no marginal constraints except that the table total is fixed. For a 3 × 2 test case, a bootstrap variance estimator yielded reliable estimates of precision for the adjusted cell proportions in most cases. For the n × m case, a classical variance estimator was more stable than the bootstrap variance estimators and was less biased than the other variance estimators studied.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Hammarlid, Ola. « Tools to Estimate the First Passage Time to a Convex Barrier ». Journal of Applied Probability 42, n^o 1 (mars 2005) : 61–81. http://dx.doi.org/10.1239/jap/1110381371.

Texte intégral

Résumé :

The first passage time of a random walk to a barrier (constant or concave) is of great importance in many areas, such as insurance, finance, and sequential analysis. Here, we consider a sum of independent, identically distributed random variables and the convex barrier cb(n/c), where c is a scale parameter and n is time. It is shown, using large-deviation techniques, that the limit distribution of the first passage time decays exponentially in c. Under a tilt of measure, which changes the drift, four properties are proved: the limit distribution of the overshoot is distributed as an overshoot over a linear barrier; the stopping time is asymptotically normally distributed when it is properly normalized; the overshoot and the asymptotic normal part are asymptotically independent; and the overshoot over a linear barrier is bounded by an exponentially distributed random variable. The determination of the function that multiplies the exponential part is guided by consideration of these properties.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Hammarlid, Ola. « Tools to Estimate the First Passage Time to a Convex Barrier ». Journal of Applied Probability 42, n^o 01 (mars 2005) : 61–81. http://dx.doi.org/10.1017/s0021900200000061.

Texte intégral

Résumé :

The first passage time of a random walk to a barrier (constant or concave) is of great importance in many areas, such as insurance, finance, and sequential analysis. Here, we consider a sum of independent, identically distributed random variables and the convex barrier cb(n/c), where c is a scale parameter and n is time. It is shown, using large-deviation techniques, that the limit distribution of the first passage time decays exponentially in c. Under a tilt of measure, which changes the drift, four properties are proved: the limit distribution of the overshoot is distributed as an overshoot over a linear barrier; the stopping time is asymptotically normally distributed when it is properly normalized; the overshoot and the asymptotic normal part are asymptotically independent; and the overshoot over a linear barrier is bounded by an exponentially distributed random variable. The determination of the function that multiplies the exponential part is guided by consideration of these properties.

Styles APA, Harvard, Vancouver, ISO, etc.

26

LeMay, Valerie M. « MSLS : a linear least squares technique for fitting a simultaneous system of equations with a generalized error structure ». Canadian Journal of Forest Research 20, n^o 12 (1 décembre 1990) : 1830–39. http://dx.doi.org/10.1139/x90-246.

Texte intégral

Résumé :

Forestry problems are frequently represented by a system of equations rather than a single equation. Many authors have used the two- and three-stage least squares (2SLS and 3SLS) and seemingly unrelated regressions techniques of econometrics to estimate the coefficients of these forestry systems. The assumption in using these techniques is that the error terms of individual equations are independent and identically distributed (iid), even though the equations may be contemporaneously correlated. For forestry systems, this assumption is frequently not met. The results are that the estimated variances of the coefficients are statistically biased and not consistent, and confidence intervals for the estimated coefficients and mean predicted values are inaccurate. The multistage least squares (MSLS) technique presented in this paper relaxes this iid assumption by extending 3SLS to a more generalized error structure. MSLS is a linear least squares technique that will result in consistent estimates of the coefficients and their associated variances. The error covariance matrix of the system of equations is estimated as the product of transformation matrices for each equation and an estimate of the contemporaneous covariance matrix of the system. The estimated coefficients will be asymptotically normally distributed. The limitations to the MSLS technique are that equations of the system must be linear and sample sizes must be equal for all equations. In addition, large sizes are required to calculate confidence intervals and to test hypothesis statements. The MSLS technique is demonstrated using a tree volume estimation example.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Cota-Ruiz, Juan, Rafael Gonzalez-Landaeta, Jose David Diaz-Roman, Boris Mederos-Madrazo et Ernesto Sifuentes. « A weighted and distributed algorithm for multi-hop localization ». International Journal of Distributed Sensor Networks 15, n^o 7 (juillet 2019) : 155014771986041. http://dx.doi.org/10.1177/1550147719860412.

Texte intégral

Résumé :

Multi-hop wireless sensor networks are widely used in many location-dependent applications. Most applications assume the knowledge of geographic location of sensor nodes; however, in practical scenarios, the high accuracy on position estimates of sensor nodes is still a great challenge. In this research, we propose a hop-weighted scheme that can be useful in distance-based distributed multi-hop localization. The hop-weighted localization approach generates spatial locations around position estimates of unknown sensors and computes local functions that minimize distance errors among hop-weighted and static neighboring sensors. The iterative process of each unknown sensor to re-estimate its own location allows a significant reduction of initial position estimates. Simulations demonstrate that this weighted localization approach, when compared with other schemes, can be suitable to be used as a refinement stage to improve localization in both isotropic and anisotropic networks. Also, under rough initial position estimates, the proposed algorithm achieves root mean square error values less than the radio range of unknown sensors, in average, with only a few iterations.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Newman, Andrew J., et Martyn P. Clark. « TIER version 1.0 : an open-source Topographically InformEd Regression (TIER) model to estimate spatial meteorological fields ». Geoscientific Model Development 13, n^o 4 (6 avril 2020) : 1827–43. http://dx.doi.org/10.5194/gmd-13-1827-2020.

Texte intégral

Résumé :

Abstract. This paper introduces the Topographically InformEd Regression (TIER) model, which uses terrain attributes in a regression framework to distribute in situ observations of precipitation and temperature to a grid. The framework enables our understanding of complex atmospheric processes (e.g., orographic precipitation) to be encoded into a statistical model in an easy-to-understand manner. TIER is developed in a modular fashion with key model parameters exposed to the user. This enables the user community to easily explore the impacts of our methodological choices made to distribute sparse, irregularly spaced observations to a grid in a systematic fashion. The modular design allows incorporating new capabilities in TIER. Intermediate processing variables are also output to provide a more complete understanding of the algorithm and any algorithmic changes. The framework also provides uncertainty estimates. This paper presents a brief model evaluation and demonstrates that the TIER algorithm is functioning as expected. Several variations in model parameters and changes in the distributed variables are described. A key conclusion is that seemingly small changes in a model parameter result in large changes to the final distributed fields and their associated uncertainty estimates.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Yu, Jing, Dimitar Ho et Adam Wierman. « Online Adversarial Stabilization of Unknown Networked Systems ». Proceedings of the ACM on Measurement and Analysis of Computing Systems 7, n^o 1 (27 février 2023) : 1–43. http://dx.doi.org/10.1145/3579452.

Texte intégral

Résumé :

We investigate the problem of stabilizing an unknown networked linear system under communication constraints and adversarial disturbances. We propose the first provably stabilizing algorithm for the problem. The algorithm uses a distributed version of nested convex body chasing to maintain a consistent estimate of the network dynamics and applies system level synthesis to determine a distributed controller based on this estimated model. Our approach avoids the need for system identification and accommodates a broad class of communication delay while being fully distributed and scaling favorably with the number of subsystems.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Xiao, Hu, Rongxin Cui et Demin Xu. « Cooperative multi-agent search using Bayesian approach with connectivity maintenance ». Assembly Automation 40, n^o 1 (11 avril 2019) : 76–84. http://dx.doi.org/10.1108/aa-10-2018-0152.

Texte intégral

Résumé :

Purpose This paper aims to present a distributed Bayesian approach with connectivity maintenance to manage a multi-agent network search for a target on a two-dimensional plane. Design/methodology/approach The Bayesian framework is used to compute the local probability density functions (PDFs) of the target and obtain the global PDF with the consensus algorithm. An inverse power iteration algorithm is introduced to estimate the algebraic connectivity λ2 of the network. Based on the estimated λ2, the authors design a potential field for the connectivity maintenance. Then, based on the detection probability function, the authors design a potential field for the search target. The authors combine the two potential fields and design a distributed gradient-based control for the agents. Findings The inverse power iteration algorithm can distributed estimate the algebraic connectivity by the agents. The agents can efficient search the target with connectivity maintenance with the designed distributed gradient-based search algorithm. Originality/value Previous study has paid little attention to the multi-agent search problem with connectivity maintenance. Our algorithm guarantees that the strongly connected graph of the multi-agent communication topology is always established while performing the distributed target search problem.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Karmali, Faisal, et Daniel M. Merfeld. « A distributed, dynamic, parallel computational model : the role of noise in velocity storage ». Journal of Neurophysiology 108, n^o 2 (15 juillet 2012) : 390–405. http://dx.doi.org/10.1152/jn.00883.2011.

Texte intégral

Résumé :

Networks of neurons perform complex calculations using distributed, parallel computation, including dynamic “real-time” calculations required for motion control. The brain must combine sensory signals to estimate the motion of body parts using imperfect information from noisy neurons. Models and experiments suggest that the brain sometimes optimally minimizes the influence of noise, although it remains unclear when and precisely how neurons perform such optimal computations. To investigate, we created a model of velocity storage based on a relatively new technique–“particle filtering”–that is both distributed and parallel. It extends existing observer and Kalman filter models of vestibular processing by simulating the observer model many times in parallel with noise added. During simulation, the variance of the particles defining the estimator state is used to compute the particle filter gain. We applied our model to estimate one-dimensional angular velocity during yaw rotation, which yielded estimates for the velocity storage time constant, afferent noise, and perceptual noise that matched experimental data. We also found that the velocity storage time constant was Bayesian optimal by comparing the estimate of our particle filter with the estimate of the Kalman filter, which is optimal. The particle filter demonstrated a reduced velocity storage time constant when afferent noise increased, which mimics what is known about aminoglycoside ablation of semicircular canal hair cells. This model helps bridge the gap between parallel distributed neural computation and systems-level behavioral responses like the vestibuloocular response and perception.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Kriit, Hedi Katre, Eva M. Andersson, Hanne K. Carlsen, Niklas Andersson, Petter L. S. Ljungman, Göran Pershagen, David Segersson et al. « Using Distributed Lag Non-Linear Models to Estimate Exposure Lag-Response Associations between Long-Term Air Pollution Exposure and Incidence of Cardiovascular Disease ». International Journal of Environmental Research and Public Health 19, n^o 5 (24 février 2022) : 2630. http://dx.doi.org/10.3390/ijerph19052630.

Texte intégral

Résumé :

Long-term air pollution exposure increases the risk for cardiovascular disease, but little is known about the temporal relationships between exposure and health outcomes. This study aims to estimate the exposure-lag response between air pollution exposure and risk for ischemic heart disease (IHD) and stroke incidence by applying distributed lag non-linear models (DLNMs). Annual mean concentrations of particles with aerodynamic diameter less than 2.5 µm (PM2.5) and black carbon (BC) were estimated for participants in five Swedish cohorts using dispersion models. Simultaneous estimates of exposure lags 1–10 years using DLNMs were compared with separate year specific (single lag) estimates and estimates for lag 1–5- and 6–10-years using moving average exposure. The DLNM estimated no exposure lag-response between PM2.5 total, BC, and IHD. However, for PM2.5 from local sources, a 20% risk increase per 1 µg/m3 for 1-year lag was estimated. A risk increase for stroke was suggested in relation to lags 2–4-year PM2.5 and BC, and also lags 8–9-years BC. No associations were shown in single lag models. Increased risk estimates for stroke in relation to lag 1–5- and 6–10-years BC moving averages were observed. Estimates generally supported a greater contribution to increased risk from exposure windows closer in time to incident IHD and incident stroke.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Qualls, Russell J., et Wilfried Brutsaert. « Evaluation of Spatially Distributed Ground-Based and Remotely Sensed Data to Estimate Spatially Distributed Sensible Heat Fluxes ». Water Resources Research 32, n^o 8 (août 1996) : 2489–95. http://dx.doi.org/10.1029/96wr01137.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

34

Clément, Eric, et Michel Dagenais. « Traces Synchronization in Distributed Networks ». Journal of Computer Systems, Networks, and Communications 2009 (2009) : 1–11. http://dx.doi.org/10.1155/2009/190579.

Texte intégral

Résumé :

This article proposes a novel approach to synchronize a posteriori the detailed execution traces from several networked computers. It can be used to debug and investigate complex performance problems in systems where several computers exchange information. When the distributed system is under study, detailed execution traces are generated locally on each system using an efficient and accurate system level tracer, LTTng. When the tracing is finished, the individual traces are collected and analysed together. The messaging events in all the traces are then identified and correlated in order to estimate the time offset over time between each node. The time offset computation imprecision, associated with asymmetric network delays and operating system latency in message sending and receiving, is amortized over a large time interval through a linear least square fit over several messages covering a large time span. The resulting accuracy is such that it is possible to estimate the clock offsets in a distributed system, even with a relatively low volume of messages exchanged, to within the order of a microsecond while having a very low impact on the system execution, which is sufficient to properly order the events traced on the individual computers in the distributed system.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Meuwissen, T. H. E., et M. E. Goddard. « Estimation of Effects of Quantitative Trait Loci in Large Complex Pedigrees ». Genetics 146, n^o 1 (1 mai 1997) : 409–16. http://dx.doi.org/10.1093/genetics/146.1.409.

Texte intégral

Résumé :

A method was derived to estimate effects of quantitative trait loci (QTL) using incomplete genotype information in large outbreeding populations with complex pedigrees. The method accounts for background genes by estimating polygenic effects. The basic equations used are very similar to the usual linear mixed model equations for polygenic models, and segregation analysis was used to estimate the probabilities of the QTL genotypes for each animal. Method R was used to estimate the polygenic heritability simultaneously with the QTL effects. Also, initial allele frequencies were estimated. The method was tested in a simulated data set of 10,000 animals evenly distributed over 10 generations, where 0, 400 or 10,000 animals were genotyped for a candidate gene. In the absence of selection, the bias of the QTL estimates was <2%. Selection biased the estimate of the Aa genotype slightly, when zero animals were genotyped. Estimates of the polygenic heritability were 0.251 and 0.257, in absence and presence of selection, respectively, while the simulated value was 0.25. Although not tested in this study, marker information could be accommodated by adjusting the transmission probabilities of the genotypes from parent to offspring according to the marker information. This renders a QTL mapping study in large multi-generation pedigrees possible.

Styles APA, Harvard, Vancouver, ISO, etc.

36

A.M, Sowjanya, et Shashi M. « New Proximity Estimate for Incremental Update of Non-Uniformly Distributed Clusters ». International Journal of Data Mining & ; Knowledge Management Process 3, n^o 5 (30 septembre 2013) : 91–109. http://dx.doi.org/10.5121/ijdkp.2013.3509.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

37

Ouzahra, Mohamed. « Stabilization with Decay Estimate for a Class of Distributed Bilinear Systems ». European Journal of Control 13, n^o 5 (janvier 2007) : 509–15. http://dx.doi.org/10.3166/ejc.13.509-515.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

38

Jahangir, M., D. Blacknell et R. G. White. « Accurate approximation to the optimum parameter estimate for K-distributed clutter ». IEE Proceedings - Radar, Sonar and Navigation 143, n^o 6 (1996) : 383. http://dx.doi.org/10.1049/ip-rsn:19960842.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

39

Yanovich, D. A. « Efficiency estimate for distributed computation of Gröbner bases and involutive bases ». Programming and Computer Software 34, n^o 4 (juillet 2008) : 210–15. http://dx.doi.org/10.1134/s036176880804004x.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Pang, Shujuan. « Convergence Rate Estimate of Distributed Localization Algorithms in Wireless Sensor Networks ». International Journal of Distributed Sensor Networks 11, n^o 6 (janvier 2015) : 523285. http://dx.doi.org/10.1155/2015/523285.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

41

Zaki, Ahmed, Partha P. Mitra, Lars K. Rasmussen et Saikat Chatterjee. « Estimate exchange over network is good for distributed hard thresholding pursuit ». Signal Processing 156 (mars 2019) : 1–11. http://dx.doi.org/10.1016/j.sigpro.2018.10.010.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

42

Chan, W. L., et S. P. Yung. « Error estimate for optimality of distributed parameter control problems via duality ». Journal of Applied Mathematics and Stochastic Analysis 8, n^o 2 (1 janvier 1995) : 177–88. http://dx.doi.org/10.1155/s1048953395000165.

Texte intégral

Résumé :

Sharp error estimates for optimality are established for a class of distributed parameter control problems that include elliptic, parabolic, hyperbolic systems with impulsive control and boundary control. The estimates are obtained by constructing manageable dual problems via the extremum principle.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Canclini, Antonio, Fabio Antonacci, Augusto Sarti et Stefano Tubaro. « Distributed 3D Source Localization from 2D DOA Measurements Using Multiple Linear Arrays ». Wireless Communications and Mobile Computing 2017 (2017) : 1–11. http://dx.doi.org/10.1155/2017/1049141.

Texte intégral

Résumé :

This manuscript addresses the problem of 3D source localization from direction of arrivals (DOAs) in wireless acoustic sensor networks. In this context, multiple sensors measure the DOA of the source, and a central node combines the measurements to yield the source location estimate. Traditional approaches require 3D DOA measurements; that is, each sensor estimates the azimuth and elevation of the source by means of a microphone array, typically in a planar or spherical configuration. The proposed methodology aims at reducing the hardware and computational costs by combining measurements related to 2D DOAs estimated from linear arrays arbitrarily displaced in the 3D space. Each sensor measures the DOA in the plane containing the array and the source. Measurements are then translated into an equivalent planar geometry, in which a set of coplanar equivalent arrays observe the source preserving the original DOAs. This formulation is exploited to define a cost function, whose minimization leads to the source location estimation. An extensive simulation campaign validates the proposed approach and compares its accuracy with state-of-the-art methodologies.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Hashikawa, Fumitaka, et Kazuyuki Morioka. « Convenient Position Estimation of Distributed Sensors in Intelligent Spaces Using SLAM for Mobile Robots ». Journal of Robotics and Mechatronics 27, n^o 2 (20 avril 2015) : 191–99. http://dx.doi.org/10.20965/jrm.2015.p0191.

Texte intégral

Résumé :

<div class=""abs_img""> <img src=""[disp_template_path]/JRM/abst-image/00270002/09.jpg"" width=""200"" />Overview of the proposed method</div> Intelligent space is one in which many networked sensors are distributed. The purpose of intelligent space is to support information for human beings and robots based on the integration of sensor information. Specifically, to support location-based applications in intelligent space, networked sensors must get locations of human beings or robots. To do so, sensor locations and orientations of sensors must be known in world coordinates. To measure numerous sensor locations accurately by hand, this study focuses on estimating the locations and orientations of distributed sensors in intelligent space – but doing so automatically. We propose map sharing using distributed laser range sensors and a mobile robot to estimate the locations of distributed sensors. Comparing maps of sensor and robots, sensor locations are estimated on a global map built by SLAM of a mobile robot. An ICP matching algorithm is used to improve map matching among sensors and robots. Experimental results with actual distributed sensors and a mobile robot show that the proposed system estimates sensor locations satisfactorily and improve the accuracy of a global map built by SLAM. </span>

Styles APA, Harvard, Vancouver, ISO, etc.

45

Aksomaitis, A. « Estimation of Convergence Rate in the Transfer Theorem for Maxima ». Nonlinear Analysis : Modelling and Control 13, n^o 1 (25 janvier 2008) : 3–7. http://dx.doi.org/10.15388/na.2008.13.1.14584.

Texte intégral

Résumé :

Let ZN be a maximum of independent identically distributed random variables. In this paper, a nonuniform estimate of convergence rate in the transfer theorem max-scheme is obtained. Presented results make the estimates, given in [1] and [2], more precise.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Yu, Hui, Guang Hua Lu et Hai Long Zhang. « Adaptive Sparse Recovery of Moving Targets for Distributed MIMO Radar ». Advanced Materials Research 933 (mai 2014) : 450–55. http://dx.doi.org/10.4028/www.scientific.net/amr.933.450.

Texte intégral

Résumé :

The high resolution and better recovery performance with distributed MIMO radar would be significantly degraded when the target moves at an unknown velocity. In this paper, we propose an adaptive sparse recovery algorithm for moving target imaging to estimate the velocity and image jointly with high computation efficiency. With an iteration mechanism, the proposed method updates the image and estimates the velocity alternately by sequentially minimizing the norm and the recovery error. Numerical simulations are carried out to demonstrate that the proposed algorithm can retrieve high-resolution image and accurate velocity simultaneously even in low SNR.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Moretti, G., et A. Montanari. « Inferring the flood frequency distribution for an ungauged basin using a spatially distributed rainfall-runoff model ». Hydrology and Earth System Sciences 12, n^o 4 (26 août 2008) : 1141–52. http://dx.doi.org/10.5194/hess-12-1141-2008.

Texte intégral

Résumé :

Abstract. The estimation of the peak river flow for ungauged river sections is a topical issue in applied hydrology. Spatially distributed rainfall-runoff models can be a useful tool to this end, since they are potentially able to simulate the river flow at any location of the watershed drainage network. However, it is not fully clear to what extent these models can provide reliable simulations over a wide range of spatial scales. This issue is investigated here by applying a spatially distributed, continuous simulation rainfall-runoff model to infer the flood frequency distribution of the Riarbero River. This is an ungauged mountain creek located in northern Italy, whose drainage area is 17 km2. The hydrological model is first calibrated by using a 1-year record of hourly meteorological data and river flows observed at the outlet of the 1294 km2 wide Secchia River basin, of which the Riarbero is a tributary. The model is then validated by performing a 100-year long simulation of synthetic river flow data, which allowed us to compare the simulated and observed flood frequency distributions at the Secchia River outlet and the internal cross river section of Cavola Bridge, where the basin area is 337 km2. Finally, another simulation of hourly river flows was performed by referring to the outlet of the Riarbero River, therefore allowing us to estimate the related flood frequency distribution. The results were validated by using estimates of peak river flow obtained by applying hydrological similarity principles and a regional method. The results show that the flood flow estimated through the application of the distributed model is consistent with the estimate provided by the regional procedure as well as the behaviors of the river banks. Conversely, the method based on hydrological similarity delivers an estimate that seems to be not as reliable. The analysis highlights interesting perspectives for the application of spatially distributed models to ungauged catchments.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Seo, Jiho, Jonghyeok Lee, Jaehyun Park, Hyungju Kim et Sungjin You. « Distributed Two-Dimensional MUSIC for Joint Range and Angle Estimation with Distributed FMCW MIMO Radars ». Sensors 21, n^o 22 (16 novembre 2021) : 7618. http://dx.doi.org/10.3390/s21227618.

Texte intégral

Résumé :

To estimate range and angle information of multiple targets, FMCW MIMO radars have been exploited with 2D MUSIC algorithms. To improve estimation accuracy, received signals from multiple FMCW MIMO radars are collected at the data fusion center and processed coherently, which increases data communication overhead and implementation complexity. To resolve them, we propose the distributed 2D MUSIC algorithm with coordinate transformation, in which 2D MUSIC algorithm is operated with respect to the reference radar’s coordinate at each radar in a distributed way. Rather than forwarding the raw data of received signal to the fusion center, each radar performs 2D MUSIC with its own received signal in the transformed coordinates. Accordingly, the distributed radars do not need to report all their measured signals to the data fusion center, but they forward their local cost function values of 2D MUSIC for the radar image region of interest. The data fusion center can then estimate the range and angle information of targets jointly from the aggregated cost function. By applying the proposed scheme to the experimentally measured data, its performance is verified in the real environment test.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Panzieri, Stefano, Federica Pascucci, Lorenzo Sciavicco et Roberto Setola. « Distributed Cooperative Localization ». Journal of Information Technology Research 6, n^o 3 (juillet 2013) : 49–67. http://dx.doi.org/10.4018/jitr.2013070104.

Texte intégral

Résumé :

Localization for mobile platforms, in indoor scenarios, represents a cornerstone achievement to effective develop service and field robots able to safely cooperate. This paper proposes a methodology to achieve such a result by applying a completely decentralized and distributed algorithm. The key idea of the solution developed is to enable a dynamic correction of the position estimate, computed by robots, through information, shared during random rendezvous. This objective is reached using a specific extension of the Extended Kalman Filter, called Interlaced Extended Kalman Filter, which allows exchanging the estimation performed by any single robot together with the corresponding uncertainties. The proposed unsupervised method provides a large flexibility: it facilitates the handling of heterogeneous proprioceptive and exteroceptive sensors, that can be merged taking into account both their accuracy and the system model one. The solution is particularly interesting for rescue scenario, since it is able to cope with irregular communication signals and loss of connectivity among robots team without requiring any synchronization.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Anjum, Nadeem. « Camera Localization in Distributed Networks Using Trajectory Estimation ». Journal of Electrical and Computer Engineering 2011 (2011) : 1–13. http://dx.doi.org/10.1155/2011/604647.

Texte intégral

Résumé :

This paper presents an algorithm for camera localization using trajectory estimation (CLUTE) in a distributed network of nonoverlapping cameras. The algorithm recovers the extrinsic calibration parameters, namely, the relative position and orientation of the camera network on a common ground plane coordinate system. We first model the observed trajectories in each camera's field of view using Kalman filtering, then we use this information to estimate the missing trajectory information in the unobserved areas by fusing the results of a forward and backward linear regression estimation from adjacent cameras. These estimated trajectories are then filtered and used to recover the relative position and orientation of the cameras by analyzing the estimated and observedexitandentrypoints of an object in each camera's field of view. The final configuration of the network is established by considering one camera as a reference and by adjusting the remaining cameras with respect to this reference. We demonstrate the algorithm on both simulated and real data and compare the results with state-of-the-art approaches. The experimental results show that the proposed algorithm is more robust to noisy and missing data and in case of camera failure.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Distributed estimate »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres