1,721,002 research outputs found
Competitive scenarios, community responses and organisational implications
No full textWe analyze four scenarios commonly encountered in social processes undergoing competitive pressures: resource depletion by individuals acting greedily (‘tragedy of the commons’), wasted opportunity due to over protective players (‘tragedy of the anti-commons’), crowd following (‘majority wins’) and competition for niches (‘minority wins’). We show that these scenarios are extremes of a continuous resource exploitation problem and that complex and counter-intuitive behaviors are found at the transitions between ‘pure’ scenarios. We discuss the likely community behaviors and under what conditions a centralised management intervention may play a role in the resource and community resilience
Commons and anticommons in a simple renewable resource harvest model
No full textWe consider a model where agents harvesting from a renewable resource can impose limitations on the harvesting efforts of other agents. Obstructing the harvesting of others comes at a cost, and is viewed as regulation of resource access. Thus, the agent population comprises agents that do not obstruct ("cooperators") and agents that obstruct ("obstructors"). As the economically better performing strategy spreads in the population, the system self-organizes at a level of obstruction which depends on the costs of obstruction, the obstruction efficiency and the history of the system. We show that commons and anticommons can be considered as the end points of a continuum of varying degrees of obstruction and we identify three regimes for the stationary state of the evolution dynamics: (i) a state where the system ends up in a tragedy of the commons, (ii) a tragedy of the anticommons state and (iii) a moderately regulated state in between both extremes. The more a policy environment in the moderately regulated state is tuned for optimality, the higher the danger that a fluctuation destabilizes the system into severe overexploitation
An information-based adaptive strategy for resource exploitation in competitive scenarios
Full text linkGiven an exploitation problem, in which a number of agents compete for a limited renewable resource, the optimal harvesting strategy depends on the ratio between resource availability and exploitation effort. For scarce resource a purely competitive, greedy strategy outperforms a more collaborative approach based on the Collective Intelligence, while for more abundant resource the opposite holds. The rationale for this behaviour lies in the amount of information each strategy is able to provide and a combined strategy is possible according to which agents choose dynamically the most informative strategy according to a minimum entropy criterion. This approach, which provides best performance for both under and over-exploited scenarios, can be used to monitor the resource status for management purposes and is effective in both centralised and decentralised decision making
Strategies for resource exploitation
No full textIn a mixed strategy, game-theoretical scenario mimicking the behaviour of fishing vessels competing for a limited renewable resource, agents following either a Collective Intelligence or a purely selfish strategy quickly outperform fully cooperative teams as well as agents not planning for future action by acting randomly. The stable balance between fully selfish agents and the Collective Intelligence depends subtly on the ratio of instantaneous demand to instantaneously available resource as well as on the dynamics of the resource itself. This suggests use of ratio of strategies as an indicator of the level of resource exploitation. The Collective Intelligence performance proves to be extremely robust to uncertain information, especially when longer records of historical catch are accounted for
Measurements of Soil Carbon Dioxide Emissions from Two Maize Agroecosystems at Harvest under Different Tillage Conditions
Full text linkIn this study a comparison of the soil CO2 fluxes emitted from two maize (Zea mays L.) fields with the same soil type was performed. Each field was treated with a different tillage technique: conventional tillage (30 cm depth ploughing) and no-tillage. Measurements were performed in the Po Valley (Italy) from September to October 2012, covering both pre- and postharvesting conditions, by means of two identical systems based on automatic static soil chambers. Main results show that no-tillage technique caused higher CO2 emissions than conventional tillage (on average 2.78 and 0.79 μmol CO2 m−2 s−1, resp.). This result is likely due to decomposition of the organic litter left on the ground of the no-tillage site and thus to an increased microbial and invertebrate respiration. On the other hand, fuel consumption of conventional tillage technique is greater than no-tillage consumptions. For these reasons this result cannot be taken as general. More investigations are needed to take into account all the emissions related to the field management cycle
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
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
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