202,866 research outputs found

    Assessing the performance of urban water utilities in Mozambique using a water utility performance index

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    Benchmarking analysis has become a strategic tool through which water regulators around the world measure the performance of water utilities. Since 2008, the Water Regulatory Council of Mozambique has been implementing a benchmarking framework to analyse the performance of urban water utilities. This paper develops a water utility performance index (WUPI) to analyse the performance of the regulated urban water supply utilities in Mozambique during 2010 and 2012. The WUPI is based on 12 key performance indicators grouped into 3 components (economic sustainability, operational sustainability and quality of the services). The WUPI was built in 6 different ways, using 2 weighting systems (equal weights and non-equal weights), and 3 different functional forms to aggregate the indicators (additive aggregation, hybrid aggregation and TOPSIS aggregation). The results obtained show that the performance of the water supply utilities in the analysed period has evolved positively. They also indicate that the performance level between the analysed water supply utilities is heterogeneous, with water supply utilities earning both high and low scores of the WUPI. Water utilities that were working through water operator partnership mechanics obtained higher performances in terms of the WUPI. This information should enable water supply utility managers and decision makers to prioritise activities and implement working models that allow for improvement of the performance of water supply utilities.Keywords: Benchmarking; composite indicators; performance indicators; Mozambiqu

    Fairs for e-commerce: the benefits of aggregating buyers and sellers

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    In recent years, many new and interesting models of successful online business have been developed. Many of these are based on the competition between users, such as online auctions, where the product price is not fixed and tends to rise. Other models, including group-buying, are based on cooperation between users, characterized by a dynamic price of the product that tends to go down. There is not yet a business model in which both sellers and buyers are grouped in order to negotiate on a specific product or service. The present study investigates a new extension of the group-buying model, called fair, which allows aggregation of demand and supply for price optimization, in a cooperative manner. Additionally, our system also aggregates products and destinations for shipping optimization. We introduced the following new relevant input parameters in order to implement a double-side aggregation: (a) price-quantity curves provided by the seller; (b) waiting time, that is, the longer buyers wait, the greater discount they get; (c) payment time, which determines if the buyer pays before, during or after receiving the product; (d) the distance between the place where products are available and the place of shipment, provided in advance by the buyer or dynamically suggested by the system. To analyze the proposed model we implemented a system prototype and a simulator that allow to study effects of changing some input parameters. We analyzed the dynamic price model in fairs having one single seller and a combination of selected sellers. The results are very encouraging and motivate further investigation on this topic

    A holistic and participatory information system for rural water and sanitation sector in Latin America and the Caribbean

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    The provision of water supply, sanitation and hygiene services has emerged as a top priority in the development agenda in Latin American and the Caribbean. In light of the investments envisaged to reach the targets set by the Sustainable Development Goals (SDGs), information systems (IS) will play a key role in improving decision-making. In this context, this article introduces a global IS which is increasingly implemented in a number of countries across Latin America and the Caribbean as a policy instrument to support national and local decision-making: the Rural Water Supply and Sanitation Information System (SIASAR). This information system includes a comprehensive framework for data collection, data analysis and data dissemination that simultaneously fulfils different stakeholders’ needs. This article analyses these three key monitoring issues from the viewpoint of stakeholders’ involvement. Results indicate that SIASAR represents a suitable monitoring framework to analyse sustainable services and the level of service delivered. Additionally, it is highlighted the advantages of adopting a continued participatory approach in system development, namely i) the stimulation of experience exchange and knowledge sharing among recipient counties, ii) the promotion of learnt-by-doing, and iii) an increase of regional understanding, collaboration and comparison.Postprint (published version

    Impact of different time series aggregation methods on optimal energy system design

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    Modelling renewable energy systems is a computationally-demanding task due to the high fluctuation of supply and demand time series. To reduce the scale of these, this paper discusses different methods for their aggregation into typical periods. Each aggregation method is applied to a different type of energy system model, making the methods fairly incomparable. To overcome this, the different aggregation methods are first extended so that they can be applied to all types of multidimensional time series and then compared by applying them to different energy system configurations and analyzing their impact on the cost optimal design. It was found that regardless of the method, time series aggregation allows for significantly reduced computational resources. Nevertheless, averaged values lead to underestimation of the real system cost in comparison to the use of representative periods from the original time series. The aggregation method itself, e.g. k means clustering, plays a minor role. More significant is the system considered: Energy systems utilizing centralized resources require fewer typical periods for a feasible system design in comparison to systems with a higher share of renewable feed-in. Furthermore, for energy systems based on seasonal storage, currently existing models integration of typical periods is not suitable

    On harmonic emission assessment : a discriminative approach

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    Model of Controlled Synthesis of Uniform Colloid Particles: Cadmium Sulfide

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    The recently developed two-stage growth model of synthesis of monodispersed polycrystalline colloidal particles is utilized and improved to explain growth of uniform cadmium sulfide spheres. The model accounts for the coupled processes of nucleation, which yields nanocrystalline precursors, and aggregation of these subunits to form the final particles. The key parameters have been identified that control the size selection and uniformity of the CdS spheres, as well as the dynamics of the process. This approach can be used to generally describe the formation of monodispersed colloids by precipitation from homogeneous solutions.Comment: 20 pages in PD
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