270 research outputs found

    Bayesian inference analysis of the uncertainty linked to the evaluation of potential flood damage in urban areas.

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    Flood damage in urbanized watersheds may be assessed by combining the flood depth–damage curves and the outputs of urban flood models. The complexity of the physical processes that must be simulated and the limited amount of data available for model calibration may lead to high uncertainty in the model results and consequently in damage estimation. Moreover depth–damage functions are usually affected by significant uncertainty related to the collected data and to the simplified structure of the regression law that is used. The present paper carries out the analysis of the uncertainty connected to the flood damage estimate obtained combining the use of hydraulic models and depth–damage curves. A Bayesian inference analysis was proposed along with a probabilistic approach for the parameters estimating. The analysis demonstrated that the Bayesian approach is very effective considering that the available databases are usually short

    Multivariate Statistical Analysis for Water Demand Modeling

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    The actual level of water demand is the driving force behind the hydraulic dynamics in water distribution systems. Consequently, it is crucial to estimate it as accurately as possible in order to result in reliable simulation models. In this paper, a copula-based multivariate analysis has been proposed and used for demand prediction for given return period. The analysis is applied to water consumption data collected in the water distribution network of Palermo (Italy). The approach showed to produce consisted demand patterns and to be a powerful tool to be coupled with water distribution network models for design or analysis problems. (C) 2014 Published by Elsevier Ltd

    Children's Understanding of Psychogenic Bodily Reactions

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65537/1/1467-8624.00289.pd

    Definition of Water Meter Substitution Plans based on a Composite Indicator

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    This paper presents a water meter substitution plan based on a composite "Replacement indicator" which was defined and compared with common substitution strategies based on meter age and on run-to-fail approaches. The methodology was applied to one of the 17 sub-networks in which the Palermo city water distribution network (Italy) is divided. The analysis was carried out considering a substitution budget limitation and the results showed that the use of "Replacement indicator" outperform the classical substitution strategies based on meter age because it takes into account some other variables that may affect meter precision and wearing. (C) 2013 The Authors. Published by Elsevier Ltd

    Analysis of the impact of intermittent distribution by modelling the network-filling process

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    In many countries, users acquire private tanks to reduce their vulnerability to water scarcity. In such conditions, water managers often apply intermittent distribution in order to reduce the water volumes supplied to the users. This practice modifies the hydraulic behaviour of the network and determines competition among users that need to collect enough water resource for their uses. Intermittent distribution is thus responsible for the inequality that can occur among users: those located in advantaged positions of the network are able to obtain water resources soon after the service period begins, while others have to wait much longer, after the network is full. This paper analyses the inequalities that take part when intermittent distribution is applied in water scarcity scenarios. Considering the complexity of the process, the analysis was performed by means of an unsteady numerical model. The model was applied to a real case study which provided interesting insights into the network filling process, helping to highlight the advantaged and disadvantaged areas of the network in different water scarcity scenarios

    The Effect of Damage Functions on Urban Flood Damage Appraisal

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    Flooding damage appraisal can been obtained by interpolating real damage data caused by historical flooding events or accounting the effects of a flood in terms of the depreciation of assets. Most often, the expected damage is evaluated by means of damage functions describing the relationship occurring between the damage and hydraulic characteristics of flood. The present paper aims to evaluate the uncertainty linked to the choice of the depth-damage function adopted in the flood damage analysis. Several possible depth-damage function formulations were selected in literature and applied to historical flooding events monitored in the "Centro Storico" catchment in Palermo (Italy). (C) 2013 The Authors. Published by Elsevier Ltd

    Natural Mentors and Adolescent Resiliency: A Study with Urban Youth

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    Natural mentors may play an important role in the lives of adolescents. We interviewed 770 adolescents from a large Midwestern city. Fifty-two percent reported having a natural mentor. Those with natural mentors were less likely to smoke marijuana or be involved in nonviolent delinquency, and had more positive attitudes toward school. Natural mentors had no apparent effect on anxiety or depression. Using the resiliency theory framework, natural mentors were found to have compensatory but not protective effects on problem behaviors, and both compensatory and protective effects on school attitudes. Direct and indirect (mediated) effects of natural mentors are explored for problem behaviors and school attitudes. The potential importance of natural mentors is supported, and implications for future research are considered.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44059/1/10464_2004_Article_368417.pd

    Notas metodológicas para investigaciones sobre política económica

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    Análisis de métodos de investigación sobre política económica con énfasis en el Uruguay. Discute categorías utilizadas, delimitación teórica e histórica, evaluación de los resultados; notas bibliográficas

    Energy Recovery in Water Distribution Networks. Implementation of Pumps as Turbine in a Dynamic Numerical Model

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    In complex networks characterized by the presence of private tanks, water managers usually apply intermittent distribution, thus reducing the water volumes supplied to the users, or use Pressure Reduction Valves (PRV) for controlling pressure in the network. The application of Pump As Turbines (PATs) appears as an alternative and sustainable solution to either control network pressure as well as to produce energy. In the present paper, the hydrodynamic model, already presented by De Marchis et al. (2011) was further developed introducing the dynamic analysis of PATs. The model was applied to a district of Palermo network (Italy) characterized by intermittent distribution and by inequities among the user in term of water supply. (C) 2013 The Authors. Published by Elsevier Ltd

    Tourists' perceptions and willingness to pay for the control of Opuntia stricta invasion in protected areas: A case study from South Africa

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    Invasive alien plants have a long history of establishment in the national parks of South Africa.In particular, Opuntia stricta (sour prickly pear) has invaded several protected areas in thecountry, threatening the biodiversity conservation mandate of these conservation areas. Thisarticle focuses on the economic estimation of O. stricta's negative impacts in protected areas byusing Contingent Valuation surveys conducted amongst a sample of tourists in the PilanesbergNational Park (North West Parks and Tourism Board, South Africa). Tourists' familiarity andawareness of selected invasive alien plants and their willingness to pay for the implementationof a control programme for O. stricta were assessed. The results show that many tourists arefamiliar with invasive alien plants and their (positive and negative) impacts and, in particular,perceived the presence of O. stricta to be negative, due to the impacts on aesthetics and recreation.Socio-demographic characteristics, as well as individual attitudes and biocentric beliefs, have aninfluence on the willingness to contribute financially to a control programme for O. stricta. Theindividual willingness to pay assessment found that the majority of respondents (78%) werewilling to pay a higher entrance fee (an additional R57.30 or $7.00 per day) for a hypotheticalprogramme to control the invasion of O. stricta in the Pilanesberg National Park.Conservation implications: The willingness of tourists to pay for O. stricta managementprovides useful insights in the decision-making process of park management. The resultsare encouraging, since, in general, tourists are aware of the problem and are in support ofproviding additional economic input for preventing future alien plant invasions
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