51,341 research outputs found

    Comparing consortial repositories: a model-driven analysis

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    This study aims to provide a comparative assessment of different repository consortia as a reference to inform future work in the area. A review of the literature was used to identify repository consortia, and their features were compared. Three models of consortial repositories were derived from this comparison, based on their structure and aims. The consortial models were based around either: creating a shared repository for the members, developing a repository software platform or creating a metadata harvesting service to aggregate content. Using case studies of each type of repository consortium, each model was assessed in terms of its particular strengths and weaknesses. These strengths were then compared across the models to enable those considering a consortial repository project to assess which model, or combination of models, would best address their needs and to aid in project planning

    SLIS Student Research Journal, Vol. 6, Iss. 1

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    Dual-band substrate integrated waveguide textile antenna with integrated solar harvester

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    A dual-band wearable textile antenna based on substrate integrated waveguide technology is presented for operation in the [2.4-2.4835]-GHz Industrial, Scientific and Medical band and the [2.5-2.69]-GHz 4G LTE band 7. The antenna features an integrated flexible solar harvesting system, consisting of a flexible solar cell, a power management system, and energy storage. All these components are judiciously positioned on the antenna platform in order not to affect its radiation performance. The measured reflection coefficients and radiation characteristics after bending and deploying the antenna on a human body prove that the antenna is well suited for on-body use. A measured on-body antenna gain and radiation efficiency of 5.0 dBi and 89% are realized. Measurements in a real-life situation have demonstrated the ability to scavenge a maximum of 53 mW by means of a single integrated flexible solar cell

    Can forest management based on natural disturbances maintain ecological resilience?

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    Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

    Environmentally sustainable practices at UK airports

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    In response to growing concerns about rising energy bills, long-term energy security and the environmental impacts of greenhouse gas emissions, airport operators worldwide are increasingly implementing new sustainable practices to help reduce costs, increase efficiency and reduce their environmental impacts. These initiatives include the installation of on-site wind turbines, biomass plants, and ‘smart' heating and lighting systems as well as other ‘green' initiatives including rainwater harvesting initiatives, improved recycling facilities and financial incentives to encourage staff to travel to work by modes other than the private car. Drawing on specific examples, this paper examines the ways in which UK airports have responded to the challenge of reducing the environmental impacts of operations for which they are directly responsible by implementing green and sustainable energy and working practices. The paper concludes by discussing the importance of sustainable airport practices in light of future growth in key emerging aviation markets

    CLIMATE AND COOPERATION: A NEW PERSPECTIVE ON THE MANAGEMENT OF SHARED FISH STOCKS

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    Climate regime shifts occur at irregular intervals and have profound and persistent impacts on ocean temperature and circulation patterns and on the dynamics of marine fish populations. Despite a growing scientific literature and some attention to the implications of such regime shifts for domestic fisheries, the issue has received little attention in the context of international fishery management. This paper presents evidence for the significance of climatic regime shifts, and draws upon the recent history of conflict between Canada and the United States over Pacific salmon management to illustrate the dangers that unpredicted, unanticipated environmental regime shifts pose for efforts to maintain international cooperation. This suggests a need for greater attention to this issue. Fishery agreements can be made more resilient to the impacts of such environmental changes by explicitly building in flexibility — for example, by allowing the use of side payments. In addition, pre-agreements on procedures to be followed in the event of sustained changes in fish stock productivity or migration patterns, and cooperation on developing common scientific understandings, can help to prevent destructive conflicts. Finally, the literature employing game theoretic shared-fishery models could be further developed to focus on providing practical guidance for maintaining cooperation in the presence of unpredictable and persistent environmental changes.climate regimes, shared fisheries, potential conflicts, uncertainty, Q21, Q22, Resource /Energy Economics and Policy,

    The ecomics of ecosystems and biodiversity: scoping the scale

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    The G8 decided in March 2007 to initiate a “Review on the economics of biodiversity loss”, in the so called Potsdam Initiative: 'In a global study we will initiate the process of analysing the global economic benefit of biological diversity, the costs of the loss of biodiversity and the failure to take protective measures versus the costs of effective conservation. The study is being supported by the European Commission (together with the European Environmental Agency and in cooperation with the German Government. “The objective of the current study is to provide a coherent overview of existing scientific knowledge upon which to base the economics of the Review, and to propose a coherent global programme of scientific work, both for Phase 2 (consolidation) and to enable more robust future iterations of the Review beyond 2010.

    Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey

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    Wireless sensor networks (WSNs) consist of autonomous and resource-limited devices. The devices cooperate to monitor one or more physical phenomena within an area of interest. WSNs operate as stochastic systems because of randomness in the monitored environments. For long service time and low maintenance cost, WSNs require adaptive and robust methods to address data exchange, topology formulation, resource and power optimization, sensing coverage and object detection, and security challenges. In these problems, sensor nodes are to make optimized decisions from a set of accessible strategies to achieve design goals. This survey reviews numerous applications of the Markov decision process (MDP) framework, a powerful decision-making tool to develop adaptive algorithms and protocols for WSNs. Furthermore, various solution methods are discussed and compared to serve as a guide for using MDPs in WSNs
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