35,332 research outputs found
Interactive Problem Structuring with ICZM Stakeholders
Integrated Coastal Zone Management (ICZM) is struggling with a lack of science-management integration. Many computer systems, usually known as “decision support systems”, have been developed with the intention to make scientific knowledge about complex systems more accessible for coastal managers. These tools, allowing a multi-disciplinary approach with multi-criteria analyses, are designed for well-defined, structured problems. However, in practice stakeholder consensus on the problem structure is usually lacking. Aim of this paper is to explore the practical opportunities for the new so-called Quasta approach to structure complex problems in a group setting. This approach is based on a combination of Cognitive Mapping and Qualitative Probabilistic Networks. It comprehends a new type of computer system which is quite simple and flexible as well. The tool is tested in two workshops in which various coastal management issues were discussed. Evaluations of these workshops show that (1) this system helps stakeholders to make them aware of causal relationships, (2) it is useful for a qualitative exploration of scenarios, (3) it identifies the quantitative knowledge gaps of the problem being discussed and (4) the threshold for non technicians to use this tool is quite low.Integrated Coastal Zone Management, Problem Structuring, Stakeholder Participation, Cognitive Mapping, Interactive Policy Making
Filling-in the Forms: Surface and Boundary Interactions in Visual Cortex
Defense Advanced Research Projects Agency and the Office of Naval Research (NOOOI4-95-l-0409); Office of Naval Research (NOOO14-95-1-0657)
Consciousness CLEARS the Mind
A full understanding of consciouness requires that we identify the brain processes from which conscious experiences emerge. What are these processes, and what is their utility in supporting successful adaptive behaviors? Adaptive Resonance Theory (ART) predicted a functional link between processes of Consciousness, Learning, Expectation, Attention, Resonance, and Synchrony (CLEARS), includes the prediction that "all conscious states are resonant states." This connection clarifies how brain dynamics enable a behaving individual to autonomously adapt in real time to a rapidly changing world. The present article reviews theoretical considerations that predicted these functional links, how they work, and some of the rapidly growing body of behavioral and brain data that have provided support for these predictions. The article also summarizes ART models that predict functional roles for identified cells in laminar thalamocortical circuits, including the six layered neocortical circuits and their interactions with specific primary and higher-order specific thalamic nuclei and nonspecific nuclei. These prediction include explanations of how slow perceptual learning can occur more frequently in superficial cortical layers. ART traces these properties to the existence of intracortical feedback loops, and to reset mechanisms whereby thalamocortical mismatches use circuits such as the one from specific thalamic nuclei to nonspecific thalamic nuclei and then to layer 4 of neocortical areas via layers 1-to-5-to-6-to-4.National Science Foundation (SBE-0354378); Office of Naval Research (N00014-01-1-0624
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The correlation structure of spatial autoregressions
This paper investigates how the correlations implied by a first-order simultaneous
autoregressive (SAR(1)) process are affected by the weights matrix and the autocorrelation
parameter. A graph theoretic representation of the covariances in terms of
walks connecting the spatial units helps to clarify a number of correlation properties
of the processes. In particular, we study some implications of row-standardizing
the weights matrix, the dependence of the correlations on graph distance, and the
behavior of the correlations at the extremes of the parameter space. Throughout
the analysis differences between directed and undirected networks are emphasized.
The graph theoretic representation also clarifies why it is difficult to relate properties
ofW to correlation properties of SAR(1) models defined on irregular lattices
The Organization and Control of an Evolving Interdependent Population
Starting with Darwin, biologists have asked how populations evolve from a low
fitness state that is evolutionarily stable to a high fitness state that is
not. Specifically of interest is the emergence of cooperation and
multicellularity where the fitness of individuals often appears in conflict
with that of the population. Theories of social evolution and evolutionary game
theory have produced a number of fruitful results employing two-state two-body
frameworks. In this study we depart from this tradition and instead consider a
multi-player, multi-state evolutionary game, in which the fitness of an agent
is determined by its relationship to an arbitrary number of other agents. We
show that populations organize themselves in one of four distinct phases of
interdependence depending on one parameter, selection strength. Some of these
phases involve the formation of specialized large-scale structures. We then
describe how the evolution of independence can be manipulated through various
external perturbations.Comment: To download simulation code cf. article in Proceedings of the Royal
Society, Interfac
The Evolutionary Unfolding of Complexity
We analyze the population dynamics of a broad class of fitness functions that
exhibit epochal evolution---a dynamical behavior, commonly observed in both
natural and artificial evolutionary processes, in which long periods of stasis
in an evolving population are punctuated by sudden bursts of change. Our
approach---statistical dynamics---combines methods from both statistical
mechanics and dynamical systems theory in a way that offers an alternative to
current ``landscape'' models of evolutionary optimization. We describe the
population dynamics on the macroscopic level of fitness classes or phenotype
subbasins, while averaging out the genotypic variation that is consistent with
a macroscopic state. Metastability in epochal evolution occurs solely at the
macroscopic level of the fitness distribution. While a balance between
selection and mutation maintains a quasistationary distribution of fitness,
individuals diffuse randomly through selectively neutral subbasins in genotype
space. Sudden innovations occur when, through this diffusion, a genotypic
portal is discovered that connects to a new subbasin of higher fitness
genotypes. In this way, we identify innovations with the unfolding and
stabilization of a new dimension in the macroscopic state space. The
architectural view of subbasins and portals in genotype space clarifies how
frozen accidents and the resulting phenotypic constraints guide the evolution
to higher complexity.Comment: 28 pages, 5 figure
From viability to sustainability: the contribution of the viable systems approach (VSA)
The current dynamics of business systems require new ways of conceiving the role of single entities. On this basis, a complex of interactions between the company and the reference context must be activated to guarantee survival dynamics. From these considerations re-emerge the ideas of Peccei (2013) and King (2013) that recognise in the systemic thought the foundations for a sustainable society. The present study derives from these considerations, and aims at contributing to the advancement of the knowledge necessary to overcome the challenges in the sustainability field. The methodological approach, albeit heuristic, can be traced back to the positive scientific and constructivist method. The results of the study showed the prevalence of qualitative and subjective
techniques, accompanied by the so-called inductive method, testifying to the intense interaction between the scholar and the object investigated. With regard to future research, it would be interesting to construct a flexible, scalable and extensible model to recover both a database and an ontology for
the theoretical framework
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