5 resultados para Conceptual models

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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In studies related to deep geological disposal of radioactive waste, it is current practice to transfer external information (e.g. from other sites, from underground rock laboratories or from natural analogues) to safety cases for specific projects. Transferable information most commonly includes parameters, investigation techniques, process understanding, conceptual models and high-level conclusions on system behaviour. Prior to transfer, the basis of transferability needs to be established. In argillaceous rocks, the most relevant common feature is the microstructure of the rocks, essentially determined by the properties of clay–minerals. Examples are shown from the Swiss and French programmes how transfer of information was handled and justified. These examples illustrate how transferability depends on the stage of development of a repository safety case and highlight the need for adequate system understanding at all sites involved to support the transfer.

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Water-conducting faults and fractures were studied in the granite-hosted A¨ spo¨ Hard Rock Laboratory (SE Sweden). On a scale of decametres and larger, steeply dipping faults dominate and contain a variety of different fault rocks (mylonites, cataclasites, fault gouges). On a smaller scale, somewhat less regular fracture patterns were found. Conceptual models of the fault and fracture geometries and of the properties of rock types adjacent to fractures were derived and used as input for the modelling of in situ dipole tracer tests that were conducted in the framework of the Tracer Retention Understanding Experiment (TRUE-1) on a scale of metres. After the identification of all relevant transport and retardation processes, blind predictions of the breakthroughs of conservative to moderately sorbing tracers were calculated and then compared with the experimental data. This paper provides the geological basis and model calibration, while the predictive and inverse modelling work is the topic of the companion paper [J. Contam. Hydrol. 61 (2003) 175]. The TRUE-1 experimental volume is highly fractured and contains the same types of fault rocks and alterations as on the decametric scale. The experimental flow field was modelled on the basis of a 2D-streamtube formalism with an underlying homogeneous and isotropic transmissivity field. Tracer transport was modelled using the dual porosity medium approach, which is linked to the flow model by the flow porosity. Given the substantial pumping rates in the extraction borehole, the transport domain has a maximum width of a few centimetres only. It is concluded that both the uncertainty with regard to the length of individual fractures and the detailed geometry of the network along the flowpath between injection and extraction boreholes are not critical because flow is largely one-dimensional, whether through a single fracture or a network. Process identification and model calibration were based on a single uranine breakthrough (test PDT3), which clearly showed that matrix diffusion had to be included in the model even over the short experimental time scales, evidenced by a characteristic shape of the trailing edge of the breakthrough curve. Using the geological information and therefore considering limited matrix diffusion into a thin fault gouge horizon resulted in a good fit to the experiment. On the other hand, fresh granite was found not to interact noticeably with the tracers over the time scales of the experiments. While fracture-filling gouge materials are very efficient in retarding tracers over short periods of time (hours–days), their volume is very small and, with time progressing, retardation will be dominated by altered wall rock and, finally, by fresh granite. In such rocks, both porosity (and therefore the effective diffusion coefficient) and sorption Kds are more than one order of magnitude smaller compared to fault gouge, thus indicating that long-term retardation is expected to occur but to be less pronounced.

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Since European settlement, there has been a dramatic increase in the density, cover and distribution of woody plants in former grassland and open woodland. There is a widespread belief that shrub encroachment is synonymous with declines in ecosystem functions, and often it is associated with landscape degradation or desertification. Indeed, this decline in ecosystem functioning is considered to be driven largely by the presence of the shrubs themselves. This prevailing paradigm has been the basis for an extensive program of shrub removal, based on the view that it is necessary to reinstate the original open woodland or grassland structure from which shrublands are thought to have been derived. We review existing scientific evidence, particularly focussed on eastern Australia, to question the notion that shrub encroachment leads to declines in ecosystem functions. We then summarise this scientific evidence into two conceptual models aimed at optimising landscape management to maximise the services provided by shrub-encroached areas. The first model seeks to reconcile the apparent conflicts between the patch- and landscape-level effects of shrubs. The second model identifies the ecosystem services derived from different stages of shrub encroachment. We also examined six ecosystem services provided by shrublands (biodiversity, soil C, hydrology, nutrient provision, grass growth and soil fertility) by using published and unpublished data. We demonstrated the following: (1) shrub effects on ecosystems are strongly scale-, species- and environment-dependent and, therefore, no standardised management should be applied to every case; (2) overgrazing dampens the generally positive effect of shrubs, leading to the misleading relationship between encroachment and degradation; (3) woody encroachment per se does not hinder any of the functions or services described above, rather it enhances many of them; (4) no single shrub-encroachment state (including grasslands without shrubs) will maximise all services; rather, the provision of ecosystem goods and services by shrublands requires a mixture of different states; and (5) there has been little rigorous assessment of the long-term effectiveness of removal and no evidence that this improves land condition in most cases. Our review provides the basis for an improved, scientifically based understanding and management of shrublands, so as to balance the competing goals of providing functional habitats, maintaining soil processes and sustaining pastoral livelihoods.

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Vestibular cognition has recently gained attention. Despite numerous experimental and clinical demonstrations, it is not yet clear what vestibular cognition really is. For future research in vestibular cognition, adopting a computational approach will make it easier to explore the underlying mech- anisms. Indeed, most modeling approaches in vestibular science include a top-down or a priori component. We review recent Bayesian optimal observer models, and discuss in detail the conceptual value of prior assumptions, likelihood and posterior estimates for research in vestibular cognition. We then consider forward models in vestibular processing, which are required in order to distinguish between sensory input that is induced by active self-motion, and sensory input that is due to passive self-motion. We suggest that forward models are used not only in the service of estimating sensory states but they can also be drawn upon in an offline mode (e.g., spatial perspective transformations), in which interaction with sensory input is not desired. A computational approach to vestibular cogni- tion will help to discover connections across studies, and it will provide a more coherent framework for investigating vestibular cognition.

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Synopsis: Sport organisations are facing multiple challenges originating from an increasingly complex and dynamic environment in general, and from internal changes in particular. Our study seeks to reveal and analyse the causes for professionalization processes in international sport federations, the forms resulting from it, as well as related consequences. Abstract: AIM OF ABSTRACT/PAPER - RESEARCH QUESTION Sport organisations are facing multiple challenges originating from an increasingly complex and dynamic environment in general, and from internal changes in particular. In this context, professionalization seems to have been adopted by sport organisations as an appropriate strategy to respond to pressures such as becoming more “business-like”. The ongoing study seeks to reveal and analyse the internal and external causes for professionalization processes in international sport federations, the forms resulting from it (e.g. organisational, managerial, economic) as well as related consequences on objectives, values, governance methods, performance management or again rationalisation. THEORETICAL BACKGROUND/LITERATURE REVIEW Studies on sport as specific non-profit sector mainly focus on the prospect of the “professionalization of individuals” (Thibault, Slack & Hinings, 1991), often within sport clubs (Thiel, Meier & Cachay, 2006) and national sport federations (Seippel, 2002) or on organisational change (Griginov & Sandanski, 2008; Slack & Hinings, 1987, 1992; Slack, 1985, 2001), thus leaving broader analysis on governance, management and professionalization in sport organisations an unaccomplished task. In order to further current research on above-mentioned topics, our intention is to analyse causes, forms and consequences of professionalisation processes in international sport federations. The social theory of action (Coleman, 1986; Esser, 1993) has been defined as appropriate theoretical framework, deriving in the following a multi-level framework for the analysis of sport organisations (Nagel, 2007). In light of the multi-level framework, sport federations are conceptualised as corporative actors whose objectives are defined and implemented with regard to the interests of member organisations (Heinemann, 2004) and/or other pressure groups. In order to understand social acting and social structures (Giddens 1984) of sport federations, two levels are in the focus of our analysis: the macro level examining the environment at large (political, social, economic systems etc.) and the meso level (Esser, 1999) examining organisational structures, actions and decisions of the federation’s headquarter as well as member organisations. METHODOLOGY, RESEARCH DESIGN AND DATA ANALYSIS The multi-level framework mentioned seeks to gather and analyse information on causes, forms and consequences of professionalization processes in sport federations. It is applied in a twofold approach: first an exploratory study based on nine semi-structured interviews with experts from umbrella sport organisations (IOC, WADA, ASOIF, AIOWF, etc.) as well as the analysis of related documents, relevant reports (IOC report 2000 on governance reform, Agenda 2020, etc.) and important moments of change in the Olympic Movement (Olympic revenue share, IOC evaluation criteria, etc.); and secondly several case studies. Whereas the exploratory study seeks more the causes for professionalization on an external, internal and headquarter level as depicted in the literature, the case studies rather focus on forms and consequences. Applying our conceptual framework, the analysis of forms is built around three dimensions: 1) Individuals (persons and positions), 2) Processes, structures (formalisation, specialisation), 3) Activities (strategic planning). With regard to consequences, we centre our attention on expectations of and relationships with stakeholders (e.g. cooperation with business partners), structure, culture and processes (e.g. governance models, performance), and expectations of and relationships with member organisations (e.g. centralisation vs. regionalisation). For the case studies, a mixed-method approach is applied to collect relevant data: questionnaires for rather quantitative data, interviews for rather qualitative data, as well as document and observatory analysis. RESULTS, DISCUSSION AND IMPLICATIONS/CONCLUSIONS With regard to causes of professionalization processes, we analyse the content of three different levels: 1. the external level, where the main pressure derives from financial resources (stakeholders, benefactors) and important turning points (scandals, media pressure, IOC requirements for Olympic sports); 2. the internal level, where pressure from member organisations turned out to be less decisive than assumed (little involvement of member organisations in decision-making); 3. the headquarter level, where specific economic models (World Cups, other international circuits, World Championships), and organisational structures (decision-making procedures, values, leadership) trigger or hinder a federation’s professionalization process. Based on our first analysis, an outline for an economic model is suggested, distinguishing four categories of IFs: “money-generating IFs” being rather based on commercialisation and strategic alliances; “classical Olympic IFs” being rather reactive and dependent on Olympic revenue; “classical non-Olympic IFs” being rather independent of the Olympic Movement; and “money-receiving IFs” being dependent on benefactors and having strong traditions and values. The results regarding forms and consequences will be outlined in the presentation. The first results from the two pilot studies will allow us to refine our conceptual framework for subsequent case studies, thus extending our data collection and developing fundamental conclusions. References: Bayle, E., & Robinson, L. (2007). A framework for understanding the performance of national governing bodies of sport. European Sport Management Quarterly, 7, 249–268 Chantelat, P. (2001). La professionnalisation des organisations sportives: Nouveaux débats, nouveaux enjeux [Professionalisation of sport organisations]. Paris: L’Harmattan. Dowling, M., Edwards, J., & Washington, M. (2014). Understanding the concept of professionalization in sport management research. Sport Management Review. Advance online publication. doi: 10.1016/j.smr.2014.02.003 Ferkins, L. & Shilbury, D. (2012). Good Boards Are Strategic: What Does That Mean for Sport Governance? Journal of Sport Management, 26, 67-80. Thibault, L., Slack, T., & Hinings, B. (1991). Professionalism, structures and systems: The impact of professional staff on voluntary sport organizations. International Review for the Sociology of Sport, 26, 83–97.