Search

Sectorization of a water distribution network (WDN) into district meter areas (DMAs) is considered a key strategy for an efficient management of WDNs. Typically, it involves a two-stage procedure: a clustering stage, in which the division of the WDN into clusters is performed, and a dividing stage, which involves the placement of valves and flow meters on the cluster's boundary pipes to define the DMAs. While recently published methods attempt to enhance both the clustering and dividing stages, they fail to provide decision-making flexibility. They also neglect to consider the presence of existing valves in the WDN, which can significantly affect the evaluated implementation cost, often considered the primary decision-driving factor. This paper presents improvements to the previously introduced DeNSE method for sectorization of WDNs, aiming to address these deficiencies. The methodology consists of a clustering stage, based on the network uniformity index, and a dividing stage, in which the originally used heuristic procedure is replaced with Genetic Algorithm (GA) optimization, minimizing implementation cost. Consideration of existing valves in WDN and criteria for water supply security are also included in the dividing stage to offer a better estimate of implementation costs and post-sectorized operational efficiency of the WDN. Finally, GIS visualization is implemented, and a hydraulic model of the sectorized WDN (EPANET file) is generated, providing practitioners with valuable insights and decision-making flexibility. The methodology is tested on a part of the Amsterdam WDN in the Netherlands, serving as a pilot for methodology evaluation. A range of feasible sectorization solutions is generated and compared based on implementation cost and three performance indicators (PIs). The paper provides an in-depth discussion on the selection of preferable sectorization solution. The reported results demonstrate the method's efficiency in optimizing sectorization solutions with minimum implementation cost whilst preserving the WDN operational efficiency and meeting the local design criteria. [ABSTRACT FROM AUTHOR]

In this study, we examine the performance of a multicell cellular system featuring an Non-orthogonal multiple access (NOMA) - In-band full duplex transmission (IBFD) enabled base station to improve spectral efficiency. The simultaneous transmission of multiple signals on the same frequency resource introduces several interferences and necessitates higher transmission powers to meet user’s quality of service (QoS) requirements. To address this, we introduce a heuristic approach aimed at optimizing subcarrier and power allocation with the goal of minimizing required downlink powers while ensuring QoS for each user. We also present decodability order for downlink (DL) NOMA in the presence of uplink users. Subsequently, we extend our investigation at sector level to obtain a comprehensive understanding of network dynamics within a more confined coverage area. We use orthogonal resource allocation and half duplex scenarios as benchmarks to evaluate the performance of proposed algorithm. Numerical simulations reveal that NOMA-IBFD requires lower transmit powers to meet QoS compared to the orthogonal multiple access (OMA) system, despite having more interference terms. Our key findings emphasize that the proposed algorithm not only enables users with weaker channel conditions to meet QoS requirements but also allows users with stronger channel conditions to contribute significantly to system throughput enhancement, thereby providing enhanced energy efficiency.

In South Asia, Latin America, and Africa, approximately 1.3 billion people intermittently receive water for domestic use through piped networks, known as intermittent water supply (IWS). IWS poses high operation costs and Non-Revenue Water (NRW) to water utilities, coping costs for water storage and treatment facilities to consumers, inequitable water supply, and health problems. Water scarcity is one of the main causes of water supply intermittency. This study presents a heuristic approach for sectorizing and optimum operation of IWS systems under water scarcity conditions. The methodology employs a two-step strategy: the first is a heuristic method for dividing the network into sectors based on connectivity, direct access to the source, and minimizing cut size between sectors. The second is the application of the evolutionary multiobjective optimization method, a nondominated sorting genetic algorithm (NSGA-II), for the optimum operation of IWS systems considering three objectives: the operational cost, level of equity, and level of pressure among consumers. Design variables for the optimization problem include the status of bridge pipes between sectors and the triggers on/off for the tank levels. A benchmark network was used to demonstrate the effectiveness of the proposed methodology. The results of the application of optimization for the optimal operation of nonsectorized and sectorized networks highlight the potential of improving both equity and pressure uniformity of the IWS system. Sectorization and optimal operation of IWS systems appear to have significant effects on improving pressure uniformity in different parts of the sector, improving equity among consumers and saving energy throughout the day. [ABSTRACT FROM AUTHOR]

Multi-objective optimization (MOO) considers several objectives to find a feasible set of solutions. Selecting a solution from Pareto frontier (PF) solutions requires further effort. This work proposes a new classification procedure that fits into the analytic hierarchy Process (AHP) to pick the best solution. The method classifies PF solutions using pairwise comparison matrices for each objective. Sectorization is the problem of splitting a region into smaller sectors based on multiple objectives. The efficacy of the proposed method is tested in such problems using our instances and real data from a Portuguese delivery company. A non-dominated sorting genetic algorithm (NSGA-II) is used to obtain PF solutions based on three objectives. The proposed method rapidly selects an appropriate solution. The method was assessed by comparing it with a method based on a weighted composite single-objective function. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department 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.)

Sectorization of a water distribution network (WDN) into district meter areas (DMAs) is considered a key strategy for an efficient management of WDNs. Typically, it involves a two-stage procedure: a clustering stage, in which the division of the WDN into clusters is performed, and a dividing stage, which involves the placement of valves and flow meters on the cluster’s boundary pipes to define the DMAs. While recently published methods attempt to enhance both the clustering and dividing stages, they fail to provide decision-making flexibility. They also neglect to consider the presence of existing valves in the WDN, which can significantly affect the evaluated implementation cost, often considered the primary decision-driving factor. This paper presents improvements to the previously introduced DeNSE method for sectorization of WDNs, aiming to address these deficiencies. The methodology consists of a clustering stage, based on the network uniformity index, and a dividing stage, in which the originally used heuristic procedure is replaced with Genetic Algorithm (GA) optimization, minimizing implementation cost. Consideration of existing valves in WDN and criteria for water supply security are also included in the dividing stage to offer a better estimate of implementation costs and post-sectorized operational efficiency of the WDN. Finally, GIS visualization is implemented, and a hydraulic model of the sectorized WDN (EPANET file) is generated, providing practitioners with valuable insights and decision-making flexibility. The methodology is tested on a part of the Amsterdam WDN in the Netherlands, serving as a pilot for methodology evaluation. A range of feasible sectorization solutions is generated and compared based on implementation cost and three performance indicators (PIs). The paper provides an in-depth discussion on the selection of preferable sectorization solution. The reported results demonstrate the method’s efficiency in optimizing sectorization solutions with minimum implementation cost whilst preserving the WDN operational efficiency and meeting the local design criteria.