Search

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) 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.)

The development of Directional Medium Access Control (DMAC) strategies that allow to enhance the limitations due to the use of omnidirectional antennas in Mobile ad Hoc Networks (MANET), introduces several issues that need to be properly addressed such as the Deafness problem. The use of Smart Antenna Systems (SAS) along with Directional Request To Send (DRTS) and Directional Clear To Send (DCTS) could be not sufficient to mitigate the Deafness. In this regard, a sectorized antenna approach together with a frame scheduling mechanism can improve the overall MAC performance while limiting the Deafness; however, the employment of scheduling algorithms without priority such as the Round Robin could limit the network performance especially in terms of Packet Delivery Ratio (PDR) and fairness. For this reason, we propose two approaches: the A-MSDU (Aggregation MAC Service Data Unit) MAC and a WRR (Weighted Round Robin) MAC that could allow to overcome the limitations of the Round Robin scheme applied at MAC layer in order to have an high efficiency in the overall resource allocation. More specifically, obtained results show that, through the use of frame aggregation, it is possible to considerably reduce issues implied by Round Robin such as time slice and network overhead; WRR approach, instead, is able to enhance the overall network fairness by reducing the number of collisions provided by a directional MAC based on Round Robin scheduling; this aspect translates into higher PDR performance compared to Round Robin approach. [ABSTRACT FROM AUTHOR]

Most water supply utilities in the world need to deal with daily operations of their systems while at the same time they are required to increase their efficiency. One way to increase the efficiency of the system is to divide the water distribution network into smaller subsystems called sectors. This article presents a new sectorization approach, which has been developed as part of the European FP7 research project ICeWater, focused on increasing energy efficiency. The approach is based on the combination of graph theory and multi-objective optimization applied to the system of Milan (Italy). Most existing approaches for sectorization deal with gravity sources. The methodology presented here has been applied to a system with 26 pump stations, which is an innovation and a step forward for other utilities facing similar challenges. The application of sectorization to the network of Milan has the advantage of allowing to fix the number of sectors and enabling the exploration of multiple scenarios of system operation. [ABSTRACT FROM AUTHOR]

Along with nowadays growth of urban areas and population, it is more and more important to have better water resources management, especially regarding drinking water supply. Maintaining a good state of a water distribution network poses challenges that are addressed by research community. Two of the main challenges in management of water distribution systems are the reduction of energy consumption due to the high pumping requirements in some systems and/or reduction of water losses. European Commission is encouraging research in this area and currently has funded the EU FP7 project ICeWATER, that aims at development of new ICT strategies for management and operation of water supply systems. Present article focuses on the presentation of the solution for reducing energy consumption, as it was proposed within the project. The solution is applicable to any water distribution system; therefore the principles and methodology demonstrated herein are general. [ABSTRACT FROM AUTHOR]

Sectorization is a process aimed at efficiently managing Water Supply Networks (WSNs). There are many large WSNs where the number of sectors into which they might be subdivided is initially unknown. Our method uses concepts derived from the Social Network Theory (SNT) such as centrality and community detection to obtain such subdivisions. The output is then evaluated through energy criteria. This methodology entails two very important benefits over other methods previously proposed. Firstly, it is applicable to WSNs depending on a network trunk and, secondly, it considers the technical know-how of the staff of the water utility. [ABSTRACT FROM AUTHOR]

Complex and large size hydraulic systems require the division into modules in order to simplify the analysis and the management tasks. In complex network theory, modularity index was proposed as a measure of the strength of the network division into communities, i.e. modules. Nevertheless, modularity index needs to be revised considering the specificity of the hydraulic systems as infrastructure systems. Accordingly, the classic modularity index is firstly presented and, then, tailored and modified for water distribution systems. Furthermore, a new modularity based index is proposed in order to resolve resolution limit of the original metric. [ABSTRACT FROM AUTHOR]

Abstract: The introduction of cyanide with a backflow attack into a water system was studied. The recent development of techniques for water network sectorization, aimed to improve the management of water systems, represents also an efficient way to protect networks from intentional contamination. The possibility of closing gate valves by a remote control system to create an i-DMA (isolated District Meter Area) can reduce the risk of contamination and thus the extent of damage of a terroristic attack. The study proposes a novel technique for designing i-DMAs compatible with hydraulic performance and optimized for water network protection. [Copyright &y& Elsevier]

Water distribution networks are complex systems that require innovative technological solutions enabling an integrated and rational water resource management. In this paper we present the approaches we have designed and developed within the H2OLEAK project aimed at supporting the following activities: (I) district identification, i.e. a partition of the network into independent sub-sectors and (ii) leak localization on pipelines according to flow and pressure values continuously measured at crucial points of the network. These two decision support services are both based on clustering techniques and hydraulic simulation. In particular, we propose clustering methodologies which allow managers to determine the "optimal" districts with respect to changes in demand and/or network structure and improve the possibility to identify a limited set of pipelines as the probably leaky ones, therefore reducing time and costs for physical check and consequent rehabilitation activities. [ABSTRACT FROM AUTHOR]

Objective: This study estimates the duration between the onset of psychopathology and first contact with a psychiatric service — either in a sectorized Community Mental Health Centre, or a non-sectorized service of the wider public health sector, in order to identify factors affecting help-seeking behaviour. Methods: A total of 403 individuals who sought help from a Community Mental Health Centre (CMHC) during the first three years of its operation (first single visits) were selected as the study population. They were divided into two groups, those with no previous contact with any psychiatric service (group A) and those who had already contacted a health or mental health professional in the past and prior to their referral to CMHC (group B). Results: The two groups did not exhibit significant differences regarding the reported duration (in months) of untreated mental disorders, which was found to be 16.48 (SD 15.13) and 17.15 (SD 17.30) for groups A and B respectively. With regard to the onset of mental disorder, 40% of group A and 20% of group B reported an onset within 'less than six months' prior to help seeking. Of 48 individuals with a diagnosis of 'schizophrenia', 45 had a previous contact with another healthcare service, mainly not psychiatric. They also exhibited prolonged delays in obtaining appropriate treatment. Conclusion: These findings could be attributed to the existing insufficient referral network among health services in the community, resulting in the prolonged duration of untreated mental disorders. The newly established CMHC could initiate intervention programmes in order to increase awareness of the early recognition of psychopathologic symptoms and the need for immediate treatment. [ABSTRACT FROM AUTHOR]

Abstract: Community mental health teams (CMHTs) have evolved alongside the downsizing of mental hospitals. They originated in mental health services in the UK and France in the 1950s and 60s. Generic CMHTs provide assessment and treatment for the population of a defined sector (usually stratified by age: child, adult and old age), who are referred by GPs or other health professionals. Despite considerable variation there are regular features of such teams – in particular their approach to multidisciplinary working management and caseloads – which are broadly similar and are outlined here. Common issues of CMHTs addressed in this contribution include leadership, size, the mix of disciplines and the management of multiple lines of authority. As secondary care teams, CMHTs generally need to be particularly clear about liaison and relationships with their referring GPs and arrangements around shared responsibilities with social services. Despite attempts by governments it is neither possible nor sensible to impose a rigid model of working across all circumstances. It is the need for clarity around these principles of liaison and shared working responsibilities that is essential and fixed. CMHTs have increasingly adopted standardized approaches to patient management such as the Care Programme Approach (CPA), fixed caseloads and the development of referral and discharge protocols. They remain responsive and complex organizations that have endured despite several attempts to supplant them and despite the challenges and frustrations that they can present to those who work in them. [Copyright &y& Elsevier]