Statistical performance analysis of transient-based extended blockage detection in a water supply pipeline

2019 ◽  
Vol 68 (5) ◽  
pp. 346-357 ◽  
Author(s):  
Alireza Keramat ◽  
Roohollah Zanganeh
Keyword(s):  
Lower Bound ◽  
Water Supply ◽  
Fisher Information ◽  
Noise Level ◽  
Minimum Mean Square Error ◽  
Information Matrix ◽  
Physical Parameters ◽  
Resolution Limit ◽  
Performance Bound ◽  
Water Supply Pipeline

Abstract The aim of the present research is to quantify the maximum feasible accuracy (location and size) for the transient-based blockage detection in a water supply pipeline. Owing to the randomness of transient measurements, a performance bound for the extended blockage detection exists which estimated parameters cannot exceed. The Cramér–Rao lower bound (CRLB) theorem is utilized to compute the lower bound variance of noise-induced estimation errors. It gives the minimum mean square error of any estimator according to information obtained from measurements and quantified by Fisher information. The Fisher information matrix is computed using direct differentiation of the compatibility equations obtained by the method of characteristics. The influence of relevant physical parameters including valve closure time, measurement time length and noise level on the best possible localization of blockage is investigated. The connection between the signal bandwidth, noise level and the performance limit is quantified for a typical case study. The results demonstrate trade-off between the size and the location/length of blockage estimates subject to different maneuver times, roughly offering half the wave speed times maneuver duration as the resolution limit.

scholarly journals Information theoretic analysis of hyperspectral imaging systems with applications to fluorescence microscopy

2018 ◽  
Author(s):  
Sripad Ram
Keyword(s):  
Maximum Likelihood ◽  
Least Squares ◽  
Hyperspectral Imaging ◽  
Spectral Resolution ◽  
Stokes Shift ◽  
Information Matrix ◽  
Hyperspectral Data ◽  
Spectral Unmixing ◽  
Resolution Limit ◽  
Performance Bound

AbstractWe present a general stochastic model for hyperspectral imaging data and derive analytical expressions for the Fisher information matrix for the underlying spectral unmixing problem. We investigate the linear mixing model as a special case and define a linear unmixing performance bound by using the Cramer-Rao inequality. As an application, we consider fluorescence imaging and show how the performance bound provides a spectral resolution limit that predicts how accurately a pair of spectrally similar fluorescent labels can be spectrally unmixed. We also report a novel result that shows how the spectral resolution limit can be overcome by exploiting the phenomenon of anti-Stokes shift fluorescence. In addition, we investigate how photon statistics, channel addition and channel splitting affect the performance bound. Finally by using the performance bound as a benchmark, we compare the performance of the least squares and the maximum likelihood estimators for spectral unmixing. For the imaging conditions tested here, our analysis shows that both estimators are unbiased and that the standard deviation of the maximum likelihood estimator is consistently closer to the performance bound than that of the least squares estimator. The results presented here are based on broad assumptions regarding the underlying data model and are applicable to hyperspectral data acquired with point detectors, sCMOS, CCD and EMCCD imaging detectors.EDICS: ELI-COL, COI-MCI.

Ensuring of irrigation machines application depth in uniformity’s distribution

2020 ◽  
pp. 25-30
Author(s):  
Gennadiy Ol'garenko ◽  
Boris Gordon
Keyword(s):  
Water Supply ◽  
Irrigation Depth ◽  
Application Depth ◽  
Water Supply Pipeline

A method of rain uniformity’s distribution was presented for different spraying devices, which were set on irrigation machines working in different mode of moving. A method for effective irrigation radius and width calculation was justified by using irrigation depth uniformity values from the area under water supply pipeline of the irrigation machine.

Measurement of indoor environmental parameters and analysis of the condensation phenomenon in urban utility tunnels

2022 ◽  
pp. 1420326X2110564
Author(s):  
Chuanmin Tai ◽  
Guansan Tian ◽  
Wenjun Lei
Keyword(s):  
Water Supply ◽  
Surface Temperature ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Environmental Parameters ◽  
Dew Point ◽  
Control Mode ◽  
Safe Management ◽  
Environmental Test ◽  
Water Supply Pipeline

Condensation is a major issue in the safe operation of utility tunnels. To address the condensation problem, the indoor air temperature, relative humidity (RH) and surface temperature in an urban utility tunnel in Jining were continuously measured, and the condensation conditions were surveyed and analysed. The results indicated that under natural ventilation conditions, the air temperature in the comprehensive cabin varied from 23.4°C to 24.5°C, the RH fluctuated between 86.4% and 95.3%, and the corresponding air dew point temperature (DPT) remained in the range of 22.2°C–22.9°C. The surface temperature of the water supply pipeline ranged from 17.8°C to 18.5°C, which was far lower than the DPT in the tunnel, resulting in serious condensation. A water supply pipeline with an anti-condensation design was developed based on environmental test data. A 25-mm-thick rubber plastic sponge insulation layer was used to thermally insulate the water supply pipeline, preventing further dew condensation. Furthermore, mechanical ventilation had little effect on reducing the RH in the tunnel and may actually cause dew condensation; therefore, a ventilation control mode was proposed in this study. These results are expected to provide basic data for further research and reference for the safe management of utility tunnels.

Seismic Damage Assessment of Urban Water Supply Pipeline

2013 ◽  
Vol 316-317 ◽  
pp. 723-726
Author(s):  
Jian Qun Jiang ◽  
Xiao Wen Yao ◽  
Yi Ting Lu
Keyword(s):  
Water Supply ◽  
Damage Assessment ◽  
Longitudinal Direction ◽  
Underground Water ◽  
Seismic Damage ◽  
Pipeline System ◽  
Seismic Damage Assessment ◽  
Water Pipeline ◽  
Ground Condition ◽  
Water Supply Pipeline

Water supply pipeline system is a key issue in urban lifeline engineering, and the seismic assessment for the system damage is of significant importance. In this study, method of seismic damage assessment on underground water supply pipeline is introduced. With emphasis on the uncertainties of earthquake level, ground condition, soil-pipe interaction and capacity to resist pipe deformation in longitudinal direction, the check point method is applied to the reliability study of water pipeline, and a case study is presented to show the implementation of the proposed model.

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