944 research outputs found

    A New Reliability Index for Evaluating the Performance of Water Distribution Network

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    Various reliability indices have been defined by researchers for the water distribution networks. Due to the complexity and heterogeneous nature of distribution networks, results of indicies can vary substantially and municipalities have hard time to select the most practical indicies for their networks.  This study was undertaken to develop a new method for identifying the best reliability index by considering various factors including the appropriate sensitivity to changes in network parameters, the appropriate shift in extreme conditions, the capability in covering critical condition, hydraulic condition, and water quality reliability. To accomplish the objective of the study, several water distribution networks were evaluated under multiple scenarios and the optimum reliability indices were verified with an example real water distribution network in Ahar. Controlling parameters included in scenario analysis for network reliability indices include: minimum, maximum and optimal pressure, residual chlorine in nodes, velocity in pipes, nodal pressure reliability, pipe velocity reliability, and nodal residual chlorine reliability . To evaluate the performance of defined index, a two-loop test (critical) were compared with the conventional single-lop test (normal). The performance assessment of indices obtained from this study showed that the index values ranged between 0.11 and 1.0, which indicate the normality and the appropriate sensitivity of the indices. Also, by increasing the residual chlorine of the reservoir, the network reliability index changed from 0.54 to 0.75 and then as the residual chlorine decreases in the distributon network the reliability index decreased back to 0.54. This appropriate shift in reliability index while changing residual chlorine in the network, cearly shows the the effectiveness of new method in determining the reliability indicies under extreme conditions. Also, the new method did not respond to the failure of some network components, as were evident with insignificant change in the indices values under critical conditions. From the results of this study generally can be concluded that the newly defined relability indices is an efficient way for evaluating the performance of water distribution networks

    Maximizing the Hydraulic Performance of Khomam Water Distribution Network with Optimal Planning of the Number and Speed of Pumps

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    In recent decades, due to the limitations of water resources, much research has been done in relation to the optimal operation of water distribution networks. In this regard, the use of appropriate methods to control and set the performance of pumps, valves, reservoirs and tanks in these systems are of considerable importance. In this paper, the aim is to regulate the optimal number and speed of pumps in pumping stations to maximize the hydraulic performance of water distribution networks. For this purpose, a new index is presented based on the pump speed optimization process to determine the number of turn-on pumps. In addition, the Nodal Pressure Reliability Index (NPRI) is used to evaluate the hydraulic performance of the network. The hydraulic analysis of the network is performed using EPANET and the optimization process is performed using the Modified Standard Particle Swarm Optimization algorithm (MSPSO), both of which are done in MATLAB code. The proposed method has been implemented in the form of four scenarios on the Khomam water distribution network, Gilan province. Scenarios include current status with Single Speed Pumps (SSP), Best Setting of Rotational Speed Pumps (BSRSP), Best Number of Turn on Single Speed Pumps (BNTSSP) and Best Number and Speed of Turn on Rotational Speed Pumps (BNSTRSP). Comparison of the results shows that the BSRSP and BNSTRSP scenarios with the slightest difference have the highest reliability and the lowest leakage. So that they increase the reliability of the network by 66.10 and 66.06 percent, respectively, and reduce the leakage by 23.53 and 23.48 percent, respectively. However, in the BNSTRSP scenario, the number of turn-on pumps is 13.16 percent less than the BSRSP scenario. Also, in the BNTSSP scenario where the number of turn-on pumps is less than the SSP scenario, the reliability of the network increases 21.36 percent and the leakage rate decreases by 10.36 percent, which emphasizes the efficiency of the NTPI index in improving network performance. In general, determining the number of turn-on pumps in pumping stations and optimizing the speed of variable speed pumps has a significant effect on increasing the hydraulic performance of water distribution networks, which can be very effective in saving energy and water resources and increasing network performance

    Selection of the Best Statistical Index of Nodal Pressure Values for Use in Calibrating the Hydraulic Model of the Water Distribution Network Based on Field Data Processing

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    Due to the widespread use of computers and measuring equipment in the operation of water distribution networks, a large amount of data is recorded for monitoring and evaluating the performance of water distribution networks and it is used in the modeling and calibration process. The management of these data is very necessary to achieve more accurate models on the one hand and the speed of their processing on the other hand. In this research, the purpose is to process nodal pressure field data to select the best statistical indicators for calibrating the water distribution network model. For this purpose, more than 5500 data collected in 22 stations of Ahar water distribution network and 12 stations of Oshnaviyeh water distribution network have been analyzed. First, by categorizing the data with Sturges experimental method, the probability of the data being placed in the central index categories of average, median, and mode and other categories in different stations in the times of minimum, maximum, and average consumption has been determined, and by summarizing the results, the best central index has been selected. Then, to analyze how the data changes, the minimum and maximum values, the range of variation, and the standard deviation of the data are presented along with the histogram of the categories. The trend of data variations in different stations in the minimum, maximum, and average consumption times shows that there is no specific harmony for data variations, so the maximum or minimum values of the range of variation and the standard deviation of the data are moved spatially in the stations. Also, the process of data allocation to categories shows that in the Ahar water distribution network, most data is allocated to the mode category at about 28.6 percent, followed by other categories at about 26.3 percent. Also, in the Oshnaviyeh water distribution network, the highest allocation is related to other categories with about 30.2 percent, followed by the mode category with 27.2 percent. Considering the multiplicity and dispersion of other categories and the unity of the mode category, the mode category is the best choice for both case studies. In general, by using mode values instead of other central indicators in the calibration of water distribution networks, due to the effectiveness of more field data, more favorable results will be obtained in the construction of the network model

    Hippocampal Automatic Recognition and 3D Segmentation Based on Active Appearance Model in Brain MR Images for Early Diagnosis ofAlzheimer's Disease

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    盼的:ç ”ç©¶çŁć…±æŒŻ(MAgnETIC rESOnAnCE,Mr)è„‘ć›Ÿćƒäž­æ”·é©Źçš„è‡Ș抹戆ć‰Čæ–čæł•ćŠæ”·é©Źçš„ćœąæ€ć­Šćˆ†æžæ–čæł•,äžșé˜żć°”èŒšæ”·é»˜ç—…(AlzHEIMEr'S dISEASE,Ad)çš„æ—©æœŸèŻŠæ–­æäŸ›äŸæźă€‚æ–čæł•:ćŻč20䟋Adæ‚Łè€…ć’Œ60ćæ­ŁćžžćŻčç…§è€…èĄŒMrI T1 WI 3dćźčç§Żæ‰«æ,ć»șç«‹æ”·é©Źçš„äž‰ç»Žäž»ćŠšèĄšè§‚æšĄćž‹,ćč¶ä»„æ­€æšĄćž‹ćŻčæŻäžȘäžȘäœ“è„‘éƒšçŁć…±æŒŻć›ŸćƒäžŠçš„æ”·é©Źèż›èĄŒè‡ȘćŠšèŻ†ćˆ«ć’Œäž‰ç»Žćˆ†ć‰Č,ćˆ†ćˆ«ć»șç«‹æ­ŁćžžćŻčç…§ç»„ć’ŒAdç»„çš„æ”·é©Źç»ŸèźĄćœąçŠ¶æšĄćž‹,æŻ”èŸƒAdç»„äžŽæ­ŁćžžćŻčç…§ç»„é—Žæ”·é©ŹćœąçŠ¶çš„ć·źćŒ‚æ€§ă€‚ç»“æžœ:æ”·é©Źäž‰ç»Žćˆ†ć‰Čæ–čæł•äžŽæ‰‹ćŠšćˆ†ć‰Čæ–čæł•ćœšæ”·é©Źäœ“ç§Żæ”‹é‡äžŠæ— ç»ŸèźĄć­Šć·źćˆ«(P>0.05);Adæ‚Łè€…æ”·é©Źć€Žéƒšć‘ç”ŸèŽçŒ©(P0.05).Hippocampal head atrophy was found in AD patients(P<0.05).Conclusions: Hippocampal three-dimensional segmentation and automatic identification method based on active appearance model in brain MR image is accurate and reliable;the feature of hippocampal head atrophy can be used as a basis for diagnosis of AD.ć“ˆć°”æ»šćŒ»ç§‘ć€§ć­Šç ”ç©¶ç”Ÿćˆ›æ–°ćŸș金(HCXB2010019);ć›œćź¶è‡Ș然科歊ćŸș金(81071219

    Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

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    Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (Ό̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ÂŻ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ÂŻ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),Ό̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

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    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe
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