1,721,090 research outputs found
Towards the Governance of Open Distributed Grids - A Case Study in Wireless Mobile Grids
No full textNew networking technologies such as wireless mobile grids and peer-to-peer middleware are examples of a growing class of open distributed systems whose strength is the absence of a central controlling instance and which function through the cooperation of autonomous entities that voluntarily commit resources to a common pool. The social dilemma in such systems is that it is advantageous for rational users to access the common pool resources without making any commitment of their own. This is commonly known as “free-riding”. However, if a substantial number of users followed this selfish strategy, the system itself would fail, depriving all users of its benefits. In this dissertation, we demonstrate how governance decisions can induce cooperation in such systems and how normative frameworks in combination with multi-agent system simulations can be successfully employed to analyse their effects, even at an early development stage. We show that our approach is not only practical and powerful, but also easily accessible. We demonstrate its unctionality by implementing a prototype to explore the impact of enforcement mechanisms on wireless mobile grids, a concept which has been proposed to address the energy issues arising in the next generation of mobile phones and the networks that connect them. We also infer lessons from this example for open distributed systems in general. Simulation experiments quantify the benefits of enforcement mechanisms for wireless mobile grids. We analyse these results with respect to the costs of enforcement as well as further criteria that reflect the interests of the multiple stakeholders in the system. We conclude with some observations on how the lessons learned from both process and outcomes may be applicable to the broader context of open distributed systems. In particular, we highlight (i) the use of simulation using intelligent agents and a normative framework as a means for in silico exploration of complex systems for both business and technological objectives, and (ii) the insight offered into a range of enforcement mechanisms and a better understanding of the conditions and constraints under which they are applicable
Towards the Governance of Open Distributed Grids - A Case Study in Wireless Mobile Grids
No full textNew networking technologies such as wireless mobile grids and peer-to-peer middleware are examples of a growing class of open distributed systems whose strength is the absence of a central controlling instance and which function through the cooperation of autonomous entities that voluntarily commit resources to a common pool. The social dilemma in such systems is that it is advantageous for rational users to access the common pool resources without making any commitment of their own. This is commonly known as “free-riding”. However, if a substantial number of users followed this selfish strategy, the system itself would fail, depriving all users of its benefits. In this dissertation, we demonstrate how governance decisions can induce cooperation in such systems and how normative frameworks in combination with multi-agent system simulations can be successfully employed to analyse their effects, even at an early development stage. We show that our approach is not only practical and powerful, but also easily accessible. We demonstrate its unctionality by implementing a prototype to explore the impact of enforcement mechanisms on wireless mobile grids, a concept which has been proposed to address the energy issues arising in the next generation of mobile phones and the networks that connect them. We also infer lessons from this example for open distributed systems in general. Simulation experiments quantify the benefits of enforcement mechanisms for wireless mobile grids. We analyse these results with respect to the costs of enforcement as well as further criteria that reflect the interests of the multiple stakeholders in the system. We conclude with some observations on how the lessons learned from both process and outcomes may be applicable to the broader context of open distributed systems. In particular, we highlight (i) the use of simulation using intelligent agents and a normative framework as a means for in silico exploration of complex systems for both business and technological objectives, and (ii) the insight offered into a range of enforcement mechanisms and a better understanding of the conditions and constraints under which they are applicable
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Seedling stability in waterlogged sediments: an experiment with saltmarsh plants
Full text linkSaltmarsh seedlings are exposed to extreme soil conditions in combination with mechanical disturbance by waves and tides, especially at the seaward fringe. We tested whether soil waterlogging affects resistance of seedlings to physical disturbance, thereby potentially influencing the distribution of saltmarsh species. A mesocosm experiment was conducted to investigate effects of waterlogging on plant traits, in particular root growth, and tolerance of seedlings to sediment erosion. Three species, each dominating different elevations in NW European salt marshes (Salicornia europaea, Atriplex portulacoides and Elytrigia atherica), were selected for the experiments. Individual seedlings were grown under different waterlogging treatments and finally subjected to an erosion treatment. The depth of erosion at which the seedlings toppled (Ecrit) was determined and related to above- and below-ground morphological traits of the seedlings. Resistance to erosion decreased in all 3 species from drained to completely waterlogged soil conditions, with the strongest negative impact of waterlogging on the upper marsh species E. atherica. Root length and biomass, shoot biomass and the root:shoot biomass ratio were the most important traits positively affecting Ecrit. The experiment demonstrates that rapid root growth is essential for the stability of seedlings, and is presumably of great importance for their successful establishment on tidal flats where sediment erosion may be a limiting factor. Root growth is in turn affected by a species-specific response to waterlogging. Our study suggests that this species-specific effect of waterlogging on seedling stability contributes to species sorting along the inundation gradient of coastal ecosystems
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
