New Fuzzy Performance Indices for Reliability Analysis of Water Supply Systems

Large and complex engineering systems are subject to wide range of possible future loads and conditions. Uncertainty associated with the quantification of these potential conditions is imposing a great challenge to systems‘ design, planning and management. Therefore, the assurance of satisfactory and reliable system performance cannot be simply achieved. Water supply systems, as typical example of these engineering systems, include collections of different types of facilities. These facilities are connected in complicated networks that extend over and serve broad geographical regions. As a result, water supply systems are at risk of temporary disruption in service due to natural hazards or anthropogenic causes, whether unintentional (operational errors and mistakes) or intentional (terrorist act). Quantification of risk is a pivotal step in the engineering risk and reliability analysis. In this analysis, uncertainty is measured using different system performance indices and figures of merit to evaluate its consequences for the safety of engineering systems. The probabilistic reliability analysis has been extensively used to deal with the problem of uncertainty in many engineering systems. However, application of probabilistic reliability analysis is invariably affected by the well-known engineering problem of data insufficiency. Bayesian approach and subjective probability estimation are used to evaluate, express, and communicate uncertainty that stems from lack of information or data unavailability. They introduce a formal procedure for incorporating subjective belief and engineering understanding together with the available data. Fuzzy set theory, on the other hand, was developed to try to capture people judgmental believes, or as mentioned before, the uncertainty that is caused by the lack of knowledge. Fuzzy set theory and fuzzy logic contributed successfully to the technological development in different application in real-world problems of different kinds, (Zimmermann, 1996). This study explores the utility of the fuzzy set theory in the field of engineering system reliability analysis. Three new fuzzy reliability measures are suggested: (i) reliability index, (ii) robustness index, and (iii) resiliency index. These measures are evaluated, together with fuzzy reliability measure developed by Shrestha and Duckstein (1998), using two simple hypothetical cases. The new suggested indices are proven to be able to handle different fuzzy representations. In addition, these reliability measures comply with the conceptual approach of the fuzzy sets.https://ir.lib.uwo.ca/wrrr/1007/thumbnail.jp

Application of the Fuzzy Performance Indices to the City of London Water Supply System

This study explores the utility of fuzzy performance indices: (i) combined reliabilityvulnerability index, (ii) robustness index, and (iii) resiliency index, for evaluating the performance of a complex water supply system. Regional water supply system for the City of London is used as the case study. The two main components being investigated in this case study are; (i) the Lake Huron Primary Water Supply System (LHPWSS), and (ii) the Elgin Area Primary Water Supply system (EAPWSS).https://ir.lib.uwo.ca/wrrr/1012/thumbnail.jp

A Decision Support System for Integrated Risk Management

This report provides a detailed description of the Risk Assessment Support System (RASS) for use in municipal water supply. The report explores the utility of the developed support system for evaluating the performance of a complex water supply system. A regional water supply system for the city of London is used as the case study. The theoretical foundations and computational requirements for the implementation of the RASS are provided in the report.https://ir.lib.uwo.ca/wrrr/1013/thumbnail.jp

Arctic charr (Salvelinus alpinus) in Windermere (Cumbria)

The Arctic charr of the British Isles are all non-migratory and are near their most southernmost range. Windermere is one of the few lowland lakes at southerly latitudes to contain a substantial proportion of Arctic charr. The first recorded mention of charr in Windermere was made around 1540 but it was not till the 17th century that different "sons" of charr were recognized, based on differences in their breeding behaviour. In the 1960's, the presence of two distinct populations, autumn spawners and spring spawners were discovered. In the 1980's it was shown that there were at least four races of charr in Windermere, based on genetic characteristics. Recently, the lake has changed due to inputs of phosphorus from treated sewage released into the lake resulting in eutrophication particularly in the south basin. Since the mid-1980's the numbers of charr caught in the south basin have declined

Plasmapheresis-Induced Hypercalcaemia

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy that can cause total motor paralysis in severe cases. Reports of hypercalcaemia in patients with GBS are rare. Plasmapheresis, an extracorporeal blood purification procedure for the removal of large molecular weight substances, is a wellestablished therapy for ventilated GBS patients. Although it has been observed in a few reported cases, theoretically, hypercalcaemia is not described as a plasmapheresis-related problem unless there is an underlying cause. We present a rare case of an 8-year-old child presenting with headache, diplopia, and squint, followed by disturbed conscious levels and paralysis. He was treated with both intravenous immunoglobulin and plasmapheresis, with a favourable outcome. We made a laboratory observation of hypercalcaemia which was associated with the plasmapheresis therapy without any related underlying cause. This raises the need for similar observations and the gathering of other possible acceptable explanations

Arctic Charr ( Salvelinus alpinus ) in Windermere (Cumbria)

This article commences with a brief introduction to Arctic charr (Salvelinusalpinus (L.)) and its distribution in the British Isles. The history ofinvestigations on charr in Windermere is then presented and, finally, recenttrophic changes in the lake and their consequent effects on the salmonidpopulation, are discussed

Comparison of three data-driven techniques in modelling the evapotranspiration process.

Evapotranspiration is one of the main components of the hydrological cycle as it accounts for more than two-thirds of the precipitation losses at the global scale. Reliable estimates of actual evapotranspiration are crucial for effective watershed modelling and water resource management, yet direct measurements of the evapotranspiration losses are difficult and expensive. This research explores the utility and effectiveness of data-driven techniques in modelling actual evapotranspiration measured by an eddy covariance system. The authors compare the Evolutionary Polynomial Regression (EPR) performance to Artificial Neural Networks (ANNs) and Genetic Programming (GP). Furthermore, this research investigates the effect of previous states (time lags) of the meteorological input variables on characterizing actual evapotranspiration. The models developed using the EPR, based on the two case studies at the Mildred Lake mine, AB, Canada provided comparable performance to the models of GP and ANNs. Moreover, the EPR provided simpler models than those developed by the other data-driven techniques, particularly in one of the case studies. The inclusion of the previous states of the input variables slightly enhanced the performance of the developed model, which in turn indicates the dynamic nature of the evapotranspiration process

Multi-Season Phenology Mapping of Nile Delta Croplands Using Time Series of Sentinel-2 and Landsat 8 Green LAI

Space-based cropland phenology monitoring substantially assists agricultural managing practices and plays an important role in crop yield predictions. Multitemporal satellite observations allow analyzing vegetation seasonal dynamics over large areas by using vegetation indices or by deriving biophysical variables. The Nile Delta represents about half of all agricultural lands of Egypt. In this region, intensifying farming systems are predominant and multi-cropping rotations schemes are increasing, requiring a high temporal and spatial resolution monitoring for capturing successive crop growth cycles. This study presents a workflow for cropland phenology characterization and mapping based on time series of green Leaf Area Index (LAI) generated from NASA’s Harmonized Landsat 8 (L8) and Sentinel-2 (S2) surface reflectance dataset from 2016 to 2019. LAI time series were processed for each satellite dataset, which were used separately and combined to identify seasonal dynamics for a selection of crop types (wheat, clover, maize and rice). For the combination of L8 with S2 LAI products, we proposed two time series smoothing and fitting methods: (1) the Savitzky–Golay (SG) filter and (2) the Gaussian Processes Regression (GPR) fitting function. Single-sensor and L8-S2 combined LAI time series were used for the calculation of key crop Land Surface Phenology (LSP) metrics (start of season, end of season, length of season), whereby the detection of cropland growing seasons was based on two established threshold methods, i.e., a seasonal or a relative amplitude value. Overall, the developed phenology extraction scheme enabled identifying up to two successive crop cycles within a year, with a superior performance observed for the seasonal than for the relative threshold method, in terms of consistency and cropland season detection capability. Differences between the time series collections were analyzed by comparing the phenology metrics per crop type and year. Results suggest that L8-S2 combined LAI data streams with GPR led to a more precise detection of the start and end of growing seasons for most crop types, reaching an overall detection of 74% over the total planted crops versus 69% with S2 and 63% with L8 alone. Finally, the phenology mapping allowed us to evaluate the spatial and temporal evolution of the croplands over the agroecosystem in the Nile Delta.E.A. was supported by the predoctoral scholarship, grant number ACIF/2019/187, funded by the Generalitat Valenciana and co-funded by the European Social Fund. J.V. and S.B. were supported by the European Research Council (ERC) under the ERC-2017-STG SENTIFLEX project, grant number 755617. J.V. was additionally supported by a Ramón y Cajal Contract (Spanish Ministry of Science, Innovation and Universities). S.B. was additionally supported by the Generalitat Valenciana SEJIGENT program (SEJIGENT/2021/001) and European Union—NextGenerationEU (ZAMBRANO 21-04)

Gestion de la demande en eau : politiques, pratiques et enseignements tirés au Moyen-Orient et en Afrique du Nord

Version anglaise disponible dans la Bibliothèque numérique du CRDI: Managing water demand : policies, practices and lessons from the Middle East and North Africa forum