5 results on '"spatial filtering"'
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2. Regionale Entwicklung mit und ohne räumliche Spillover-Effekte.
- Author
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Eckey, Hans-Friedrich, Kosfeld, Reinhold, and Türck, Matthias
- Abstract
Copyright of Jahrbuch fur Regionalwissenschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2007
- Full Text
- View/download PDF
3. Combining L1 and L2 Norms for a more Robust Spatial Analysis: the 'Meadian Attitude'
- Author
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Didier Josselin and Dominique Ladiray
- Subjects
spatial filtering ,robustness ,bootstrap ,meadian ,mean ,median ,Geography (General) ,G1-922 - Abstract
This paper presents a new way to look for the "center" of a statistical distribution. This concept basically combines the mean and the median, i.e. two L-norms, to define a new metric in order to improve the robustness of efficiency of an estimator. After a short historical presentation of the relationships between the mean and the median in the quest for the "center", we explain the problematic that leads us to propose a new estimator. We define the meadian, a first version of which was set up by Laplace in the early 1800s, and present its asymptotic properties. We justify the choice of bootstrap to compute the variances involved in the meadians definition. Some applications in spatial filtering are presented and discussed. In conclusion, we comment on some further developments and perspectives for the "meadian attitude".
- Published
- 2002
- Full Text
- View/download PDF
4. Dual polarization beamforming algorithm for multipath mitigation in {GNSS}
- Author
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Josef A. Nossek, Matteo Sgammini, Felix Antreich, Friederike Fohlmeister, and Andreas Iliopoulos
- Subjects
020301 aerospace & aeronautics ,Spatial correlation ,Multipath mitigation ,Spatial filtering ,Covariance function ,Computer science ,Estimation theory ,Estimator ,020206 networking & telecommunications ,02 engineering and technology ,Delay spread ,Antenna array ,0203 mechanical engineering ,Control and Systems Engineering ,Signal Processing ,Computer Science::Networking and Internet Architecture ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Rake receiver ,Computer Vision and Pattern Recognition ,Electrical and Electronic Engineering ,Software ,Multipath propagation ,Computer Science::Information Theory - Abstract
A multipath mitigation technique for GNSS is proposed.The technique exploites the change of polarization when a signal is reflected.A novel statistic based on the outputs of a correlator bank is introduced to estimate the multipath DoA and polarization.Applying the technique increases the estimation performance in the case of highly temporally or spatially correlated multipath and line-of-sight signal. This paper treats the problem of line-of-sight (LOS) parameter estimation in strong multipath environments. In the case of highly temporally and spatially correlated LOS and multipath signals, such as urban canyons, common multipath mitigation methods are highly degraded, as signal separation cannot be performed in the spatio temporal domain. In this case, we exploit the LOS and multipath polarization diversity to decouple the signals using an antenna array with right-hand-circular polarization (RHCP) and left-hand-circular polarization (LHCP) feeds. The multipath direction- of-arrival (DOA) and polarization coefficients can effectively be estimated from the LHCP spatial covariance matrix. The LOS DOA can be estimated from the RHCP spatial covariance matrix. The spatial covariance matrices are calculated from the outputs of a matched correlator bank. The DOA and polarization estimates are used to implement a dual polarization beamformer, which maximizes the LOS energy and suppresses multipath energy over both polarizations. The LOS time-delay is estimated from the beamformer output with a maximum-likelihood estimator with a significantly reduced number of parameters and computational complexity in comparison to a full model estimator. Simulation results for GPS show that the proposed dual polarization beamforming algorithm performs better than an equivalent single-polarization beamformer in a dense multipath environment.
- Published
- 2017
5. Regionale Entwicklung mit und ohne räumliche Spillover Effekte
- Author
-
Eckey, Hans-Friedrich, Kosfeld, Reinhold, and Türck, Matthias
- Subjects
Regionale Entwicklung ,Spillover-Effekt ,Agglomerationstheorie ,Spatial Econometrics ,R58 ,Agglomeration Theory ,Arbeitsproduktivität ,R11 ,Spatial Filtering ,Agglomerationseffekt ,ddc:330 ,räumliche Filterung ,Deutschland ,C21 ,räumliche Ökonometrie ,Schätzung - Abstract
Der wirtschaftliche Entwicklungsstand von Regionen hängt nicht nur von ihrer eigenen Leistungsfähigkeit ab, sondern aufgrund räumlicher Überschwappeffekte auch von jener angrenzender Wirtschaftsräume. Positive Spillovers (Lieferverflechtungen, Nutzung der Infrastruktur in Nachbarregionen u. ä.) und negative Spillovers (z. B. Umwelteffekte) begründen eine wechselseitige Beeinflussung des Entwicklungsstands von Wirtschaftsräumen. Die räumlich-ökonometrische Analyse erlaubt eine Simulation von ökonomischen Größen mit und ohne Effekte angrenzender Gebiete. Hier sei die Arbeitsproduktivität betrachtet, die als Indikator für die Leistungsfähigkeit von Wirtschaftsräumen steht. Mit Hilfe von Eigenvektoren, die die Nachbarschaftseffekte wiedergeben, wird ein erheblicher Varianzanteil der Arbeitsproduktivität erklärt. Eine die Grenzen von Wirtschaftsräumen überschreitende netzwerkbasierte Regionalpolitik erscheint damit ökonomisch sinnvoll zu sein. Insbesondere Metropolen beeinflussen in hohem Maße die Arbeitsproduktivität im Umland. Einige ostdeutsche Regionen in Brandenburg und Sachsen würden ohne das schlechte wirtschaftliche Umfeld eine deutlich überdurchschnittliche Arbeitsproduktivität aufweisen. Andere Regionen, beispielsweise im Harz und in Mecklenburg-Vorpommern, sind aufgrund der dünnen Besiedlung sowohl mit als auch ohne Berücksichtigung von Nachbarschaftseffekten unattraktiv. The development state of regions depends not only on the own efficiency, but also on spatial spillovers. Positive (backward linkages, use of the infrastructure in neighbouring economic areas etc.) and negative (e. g. environmental effects) spillovers give reasons for a mutual economic influence between regions. The spatial econometric analysis makes a simulation of the labour efficiency with and without spillovers possible. The eigenvectors, which represent the spatial effects from neighbouring regions, explain a high proportion of the labour efficiency variation. Thus a cross-border network-based regional policy makes sense. Especially metropolitan areas are influencing the labour efficiency in surrounding regions. Some East-German regions in Brandenburg and Saxony would have above-average labour efficiency without the bad economic environment. Other sparsely populated regions, for example in the Harz or in Mecklenburg- Western Pomerania, are very unattractive with and without taking into consideration neighbouring effects.
- Published
- 2005
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