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distributed sampling of Signals Linked by Sparse Filtering: Theory and Applications

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第3期58卷 1095-1109页

作者： Hormati, Ali Roy, Olivier Lu, Yue M. Vetterli, Martin Ecole Polytech Fed Lausanne Sch Comp & Commun Sci CH-1015 Lausanne Switzerland Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

We study the distributed sampling and centralized reconstruction of two correlated signals, modeled as the input and output of an unknown sparse filtering operation. This is akin to a Slepian-Wolf setup, but in the sampling rather than the lossless compression case. Two different scenarios are considered: In the case of universal reconstruction, we look for a sensing and recovery mechanism that works for all possible signals, whereas in what we call almost sure reconstruction, we allow to have a small set (with measure zero) of unrecoverable signals. We derive achievability bounds on the number of samples needed for both scenarios. Our results show that, only in the almost sure setup can we effectively exploit the signal correlations to achieve effective gains in sampling efficiency. In addition to the above theoretical analysis, we propose an efficient and robust distributed sampling and reconstruction algorithm based on annihilating filters. We evaluate the performance of our method in one synthetic scenario, and two practical applications, including the distributed audio sampling in binaural hearing aids and the efficient estimation of room impulse responses. The numerical results confirm the effectiveness and robustness of the proposed algorithm in both synthetic and practical setups.

关键词： Annihilating filter compressed sensing compressive sampling distributed sampling finite rate of innovation iterative denoising sparse reconstruction Yule-Walker system

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distributed sampling of Multiple Sinusoids with Finite Rate of Innovation

Distributed Sampling of Multiple Sinusoids with Finite Rate ...

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IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

作者： Wei, Zhiliang Fu, Ning Qiao, Liyan Harbin Inst Technol Sch Elect & Informat Engn Harbin Peoples R China

ISBN: (纸本)9781538634608

In this paper, we propose a new distributed sampling scheme for multiple sinusoids signals, which can further reduce the number of samples for each sampling channel. Based on the frequency sparse common support (SCS) model, we recover the signals using samples from several channels jointly. We propose a distributed time-staggered sampling (DTSS) system, which requires only [K + K/P] samples per non-delay channel and K samples for the delay channel when recovering K frequency components by P channels. In addition, the staggered time is required no longer than the Nyquist sampling interval in the method. Simulation results verify that the proposed methods can successfully recover the multiple sinusoids signals at a lower sampling rate.

关键词： distributed sampling frequency sparse common support multiple sinusoids sub-Nyquist

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The importance of distributed sampling in blocked functional magnetic resonance imaging designs

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NEUROIMAGE 2002年第3期17卷 1203-1206页

作者： Veltman, DJ Mechelli, A Friston, KJ Price, CJ Inst Neurol Wellcome Dept Imaging Neurosci London WC1N 3BG England Vrije Univ Amsterdam Ctr Med PET Ctr NL-1117 Amsterdam Netherlands Vrije Univ Amsterdam Ctr Med Dept Psychiat NL-1117 Amsterdam Netherlands

In this study we demonstrate the importance of distributed sampling of peristimulus time in blocked design fMRI studies. distributed sampling ensures all the components of an event-related hemodynamic response are sampled and avoids the bias incurred when stimulus presentation is time-locked to data acquisition. We found that differences in the temporal offset between stimulus presentation and data acquisition had a significant effect on some language-related activations. These effects, induced by simply shifting stimulus presentation by a fraction of the interscan interval, suggest that fixed sampling does indeed bias estimated responses, even in blocked designs. (C) 2002 Elsevier Science (USA).

关键词： distributed sampling blocked design BOLD signal

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Exact distributed sampling 30th

Exact Distributed Sampling

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30th International Colloquium on Structural Information and Communication Complexity (SIROCCO)

作者： Pemmaraju, Sriram, V Sobel, Joshua Z. Univ Iowa Dept Comp Sci Iowa City IA 52242 USA

ISBN: (纸本)9783031327322;9783031327339

Fast distributed algorithms that output a feasible solution for constraint satisfaction problems, such as maximal independent sets, have been heavily studied. There has been much less research on distributed sampling problems, where one wants to sample from a distribution over all feasible solutions (e.g., uniformly sampling a feasible solution). Recent work (Feng, Sun, Yin PODC 2017;Fischer and Ghaffari DISC 2018;Feng, Hayes, and Yin arXiv 2018) has shown that for some constraint satisfaction problems there are distributed Markov chains that mix in O(log n) rounds in the classical Local model of distributed computation. However, these methods return samples from a distribution close to the desired distribution, but with some small amount of error. In this paper, we focus on the problem of exact distributed sampling. Our main contribution is to show that these distributed Markov chains in tandem with techniques from the sequential setting, namely coupling from the past and bounding chains, can be used to design O(log n)-round Local model exact sampling algorithms for a class of weighted local constraint satisfaction problems. This general result leads to O(log n)round exact sampling algorithms that use small messages (i.e., run in the Congest model) and polynomial-time local computation for some important special cases, such as sampling weighted independent sets (aka the hardcore model) and weighted dominating sets.

关键词： distributed sampling Bounding Chains Perfect sampling Coupling from the Past

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Effects of A-D conversion nonidealities on distributed sampling in dense sensor networks

Effects of A-D conversion nonidealities on distributed sampl...

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5th International Conference on Informational Processing in Sensor Networks

作者： Ergen, Sinem Coleri Varaiya, Pravin Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

ISBN: (纸本)1595933344

We address the effect of the errors occurring at the analog-to-digital converter (ADC), from quantization noise, circuit noise, aperture uncertainty and comparator ambiguity, on the accuracy of sensor field reconstruction. We focus on the oversampling of bandlimited sensor fields in a distributed processing environment. It has previously been shown that Pulse Code Modulation (PCM) style sampling fails to decrease the quantization error above some finite sampling rate. We show that the dither-based scheme, developed to decrease the quantization error, fails to decrease random errors associated with circuit noise, aperture uncertainty and comparator ambiguity. We propose an advanced dither-based sampling scheme with the goal of reducing both kinds of errors by increasing the density of the sensor nodes. It is based on distributing the task of improving the quantization error and random error among the nodes. The error of the scheme is shown to be O(1/r(1/2)) for oversampling rate r. The maximum energy consumption per node is O(log(r)). Finally, the bit rate of the scheme is O(1/r(1/2)log(r)) and it offers robustness to node failures in terms of a graceful degradation of reconstruction error.

关键词： distributed sampling sensor networks ADC energy accuracy fault tolerance

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On distributed sampling of smooth non-bandlimited fields

On distributed sampling of smooth non-bandlimited fields

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3rd International Symposium on Information Processing in Sensor Networks

作者： Kumar, A Ishwar, P Ramchandran, K Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

ISBN: (纸本)1581138466

distributed sampling and reconstruction of a physical field using an array of sensors is a problem of considerable interest in environmental monitoring applications of sensor networks. Our recent work has focused on the sampling of bandlimited sensor fields. However, sensor fields are not perfectly bandlimited but typically have rapidly decaying spectra. In a classical sampling set-up it is possible to precede the A/D sampling operation with an appropriate analog anti-alia,sing filter. However, in the case of sensor networks, this is infeasible since sampling must precede filtering. We show that even though the effects of aliasing on the reconstruction cannot be prevented due to the "filter-less" sampling constraint, they can be suitably controlled by oversampling and carefully reconstructing the field from the samples. We show using a dither-based scheme that it is possible to estimate non-bandlimited fields with a precision that depends on how fast the spectral content of the field decays. We develop a framework for analyzing non-bandlimited fields that lead to upper bounds on the maximum pointwise error for a spatial bit rate of R bits/meter. We present results for fields with exponentially decaying spectra as an illustration. In particular, we show that for fields f(t) with exponential tails;i.e., \F(omega)\ < pialphae(-a\omega\), the maximum pointwise error decays as c(2)e(-a1rootR) + c(3)1/rootRe(-2a1rootR) with spatial bit rate R bits/meter. Finally, we show that for fields with spectra that have a finite second moment, the distortion decreases as O((1/N)(2/3)) as the density of sensors, N, scales up to infinity. We show that if D is the targeted non-zero distortion, then the required (finite) rate R scales as O(1/rootDlog1/D).

关键词： distributed sampling sensor networks non-bandlimited aliasing scaling laws dither function A/D conversion oversampling

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The Secondary Circuit Insulation online Monitoring System based on distributed Current sampling 4

The Secondary Circuit Insulation online Monitoring System ba...

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4th International Conference on New Energy and Power Engineering, ICNEPE 2024

作者： Shi, Hengchu Chen, Xiaofan Li, Yinyin You, Hao Xu, Shoudong Liang, Yong Yunnan Electric Power Dispatching and Control Center China Southern Power Grid Kunming China Scientific Research Institute of Yunnan Power Grid System Analysis Department Kunming China Beijing Jiaotong University School of Computer Science and Technology Beijing China

ISBN: (纸本)9798331516086

The secondary system is very important for the reliable power supply and safe production of the power system. It includes secondary equipment and secondary circuits. The connection status of the secondary circuits will directly affect the correct operation of protection and automation devices. To solve these devices misoperation and refuse to operate problems caused by the multipoint grounding of PT and CT secondary circuits in substations, this paper proposes an online monitoring system for the insulation status of secondary circuits based on distributed zero sequence current sampling method. This system could greatly reduce the workload of maintenance on the secondary circuits, improves operation efficiency, and ensures the reliable operation of the secondary circuit in substations. © 2024 IEEE.

关键词： CT distributed sampling Insulation online monitoring PT Secondary circuit zero sequence current

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distributed urban forest patch sampling detects edge effects and woodland condition for monitoring and management

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ECOSPHERE 2025年第3期16卷

作者： Baker, Matthew Yesilonis, Ian Templeton, Laura Shobe, Beatriz Bos, Jaelyn Sonti, Nancy F. Lautar, Katherine Univ Maryland Baltimore Cty Dept Geog & Environm Syst Baltimore MD 21250 USA Northern Res Stn Baltimore MD USA CUNY Adv Sci Res Ctr New York NY USA Johns Hopkins Univ Dept Earth & Planetary Sci Baltimore MD USA Univ Calif Santa Cruz Dept Ecol & Evolutionary Biol St Cruz CA USA Baltimore Green Space Baltimore MD USA

Urban forest patches, including woodland interiors and bounding edge habitat, result from secondary succession and fragmentation of more extensive forested landscapes in the eastern United States. Management regimes, surrounding land use, and successional processes lead to distinct environments and contribute to local and regional heterogeneity. However, many woodlands are degraded due to frequent disturbance, aggressive exotic species, and heavy browsing, which stress canopies, reduce regeneration, and may reduce ecosystem services. Effective management requires rapid, repeatable assessment of forest composition, structure, and condition at the scale of local decision-making. We present and apply a protocol for characterizing urban woodlands that generates new insight into the status of urban woodlands and baseline data for change detection over time. Samples of overstory composition, ground cover, surface soil measurements, and the Schumacher Vine Encroachment Index were collected at 845 points across each of 47 patches across Baltimore, Maryland. Simple citywide summaries allowed characterization of Baltimore's urban overstories as overwhelmingly native, though dominated by a range of successional conditions. By contrast, we found that ground layers were predominantly exotic, with abundant invasives or ruderal native species benefiting from disturbed conditions. Seven overstory types were distinguished, the majority under threat from aggressive vines. Most soils showed little evidence of compaction, but variable organic content. distributed data allowed cross-patch comparison as well as within-patch analyses along edge-to-interior gradients. Species diversity, nativity, and overstory basal area all increased toward woodland interiors, whereas soil compaction and vine encroachment decreased. Structural and compositional shifts in both overstory and ground layer species revealed indicators of edge (15.2-18.7 m) and interior (>41.5 m) conditions, as well as evidence

关键词： distributed sampling edge effects forest patches monitoring Schumacher Vine Encroachment Index urban forestry wedge prisms

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Dithered A/D Conversion of Smooth Non-Bandlimited Signals

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第5期58卷 2654-2666页

作者： Kumar, Animesh Ishwar, Prakash Ramchandran, Kannan Indian Inst Technol Dept Elect Engn Mumbai 400076 Maharashtra India Boston Univ Dept Elect & Comp Engn Boston MA 02215 USA Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

The classical method for sampling a smooth non-bandlimited signal requires a lowpass anti-aliasing filter. In applications like distributed sampling where sampling and quantization operations precede filtering, aliasing-error is inevitable. Motivated by such applications, the sampling of smooth and bounded non-bandlimited signals whose spectra have a finite absolute first moment, without the use of an analog anti-alias lowpass filter, is studied in a centralized setup. Upper bounds for the distortion-rate function are derived by first upper-bounding the distortion with a linear combination of errors due to aliasing and quantization and then balancing their contributions by selecting an appropriate reconstruction bandwidth. For a class of dithered sampling methods, it is shown that a lower quantizer-precision can be traded for a higher sampling-rate without affecting the realizable high-rate asymptotic distortion-rate characteristics. These results are applied to signals with exponentially and polynomially decaying spectral characteristics and truncated bandlimited signals to uncover the realizable distortion-rate characteristics for these signal classes.

关键词： Aliasing error analysis analog-to-digital conversion distributed sampling dithered scalar quantization non-uniform sampling oversampled rate-distortion function scaling law sensor networks smooth non-bandlimited signals

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A Square Root sampling Law for Signal Recovery

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IEEE SIGNAL PROCESSING LETTERS 2019年第4期26卷 562-566页

作者： Mohammadi, Elaheh Gohari, Amin Marvasti, Farokh Sharif Univ Technol Adv Commun Res Inst Elect Engn Dept Tehran 11365 Iran

The problem of finding the optimal node density for reconstructing a stochastic signal from its noisy samples in sensor networks is considered. The signal could he nonstationary and nonhandlimited. A weight is assigned to each location that indicates the relative importance of the signal at that location. It is shown that when the number of samples is very large, the optimal density of the samples at each location is proportional to the square root of the weight associated to that location.

关键词： distributed sampling optimal sensor density square root law

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