2,129 research outputs found

    Micro market based optimisation framework for decentralised management of distributed flexibility assets

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    Continuously changing electricity demand and intermittent renewable energy sources pose challenges to the operation of power systems. An alternative to reinforcing the grid infrastructure is to deploy and manage distributed energy storage systems. In this work, a micro-energy market is proposed for smart domestic energy trading in the low-voltage distribution systems in the context of high penetration of photovoltaic systems and battery energy storage systems. In addition, a micro-balancing market is proposed to address the congestions due to unforeseen energy imbalance. Centralised and decentralised management strategies are simulated in real time, based on generation and demand forecasts. In addition, electric vehicles are also simulated as potential storage solutions to improve grid operation. A techno-economic evaluation informs key stakeholders, in particular grid operators on strategies for a sustainable implementation of the proposed strategies. The results show that the micro-energy market reduces the energy cost for all grid users by 4.1–20.2%, depending on their configuration. In addition, voltage deviation, peak electricity demand and reverse power flow have been reduced by 12.8%, 7.7% and 85.6% respectively, with the proposed management strategies. The micro-balancing market has been demonstrated to keep the voltage profile and thermal characteristic within the set limit in case of contingency

    On Beneficial Vehicle-to-Grid (V2G) Services

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    A number of studies have investigated the possibility of extending Electric Vehicle (EV) Lithium-ion battery life by deliberately choosing to store the battery at a low to moderate state of charge. Recently, there has been considerable interest shown in the scheme of a deliberate discharge and subsequent recharge of a battery to yield an overall reduction in battery degradation whilst carrying out Vehicle-to-Grid (V2G) services (so-called `beneficial V2G'). This paper presents an investigation of the conditions permitting successful operation of this method by examining incremental time variation of the relevant parameters for two types of cells from results of the same physical size and chemistry, and similar capacity. These two types of cells are found in this present analysis to offer differing degrees of suitability for beneficial V2G

    Development and validation of a MEDLINE search filter/hedge for degenerative cervical myelopathy

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    Abstract Background Degenerative cervical myelopathy (DCM) is a common condition with many unmet clinical needs. Pooled analysis of studies is an important tool for advancing medical understanding. This process starts with a systematic search of the literature. Identification of studies in DCM is challenged by a number of factors, including non-specific terminology and index terms. Search filters or HEDGEs, are search strings developed and validated to optimise medical literature searches. We aimed to develop a search filter for DCM for the MEDLINE database. Methods The diagnostic test assessment framework of a “development dataset” and seperate “validation dataset” was used. The development dataset was formed by hand searching four leading spinal journals (Spine, Journal of Neurosurgery Spine, Spinal Cord and Journal of Spinal Disorders and Techniques) in 2005 and 2010. The search filter was initially developed focusing on sensitivity and subsequently refined using NOT functions to improve specificity. One validation dataset was formed from DCM narrative and systematic review articles and the second, articles published in April of 1989, 1993, 1997, 2001, 2005, 2009, 2013 and 2017 retrieved via the search MeSH term ‘Spine’. Metrics of sensitivity, specificity, precision and accuracy were used to test performance. Results Hand searching identified 77/1094 relevant articles for 2005 and 55/1199 for 2010. We developed a search hedge with 100% sensitivity and a precision of 30 and 29% for the 2005 and 2010 development datasets respectively. For the selected time periods, EXP Spine returned 2113 publications and 30 were considered relevant. The search filter identified all 30 relevant articles, with a specificity of 94% and precision of 20%. Of the 255 references listed in the narrative index reviews, 225 were indexed in MEDLINE and 165 (73%) were relevant articles. All relevant articles were identified and accuracy ranged from 67 to 97% over the three reviews. Of the 42 articles returned from 3 recent systematic reviews, all were identified by the filter. Conclusions We have developed a highly sensitive hedge for the research of DCM. Whilst precision is similarly low as other hedges, this search filter can be used as an adjunct for DCM search strategies

    Leading and recognizing public value

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    This article examines the relationship between leadership and public value, which is particularly challenging in a context of explicit contest and conflict. The theoretical framework is illustrated through a case study of policing rural crime. The study reveals that the police worked with multiple and competing publics rather than a single homogeneous public, and that part of their leadership role was to create and convene a public space in which different voices and divergent views could be expressed. The study notes that research needs to pay attention to the loss and displacement of public value, not solely its creation and recognition. The need to convene multiple publics required the police to lead, as part of a leadership constellation, and with political astuteness. The findings have wider relevance for other public services, and for studies of leadership and public value at the intersection between the state and civil society

    Change management: The case of the elite sport performance team

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    The effective and efficient implementation of change is often required for both successful performance and management survival across a host of contemporary domains. However, although of major theoretical and practical significance, research to date has overlooked the application of change management (hereafter CM) knowledge to the elite sport performance team environment. Considering that the success of ‘off-field’ sports businesses are largely dependent on the performances of their ‘on-field’ team, this article explores the application of current CM theorizing to this specific setting and the challenges facing its utility. Accordingly, we identify the need and importance of developing theory specific to this area, with practical application in both sport and business, through examination of current knowledge and identification of the domain's unique, dynamic and contested properties. Markers of successful change are then suggested to guide initial enquiry before the article concludes with proposed lines of research which may act to provide a valid and comprehensive theoretical account of CM to optimize the research and practice of those working in the field
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