81,093 research outputs found
The mechanisms of feature inheritance as predicted by a systems-level model of visual attention and decision making
Feature inheritance provides evidence that properties of an invisible target
stimulus can be attached to a following mask. We apply a systemslevel model of
attention and decision making to explore the influence of memory and feedback
connections in feature inheritance. We find that the presence of feedback loops
alone is sufficient to account for feature inheritance. Although our simulations
do not cover all experimental variations and focus only on the general
principle, our result appears of specific interest since the model was designed
for a completely different purpose than to explain feature inheritance. We
suggest that feedback is an important property in visual perception and provide
a description of its mechanism and its role in perception
A Model for the Generation and Transmission of Variations in Evolution
The inheritance of characteristics induced by the environment has often been
opposed to the theory of evolution by natural selection. Yet, while evolution
by natural selection requires new heritable traits to be produced and
transmitted, it does not prescribe, per se, the mechanisms by which this is
operated. The mechanisms of inheritance are not, however, unconstrained, since
they are themselves subject to natural selection. We introduce a general,
analytically solvable mathematical model to compare the adaptive value of
different schemes of inheritance. Our model allows for variations to be
inherited, randomly produced, or environmentally induced, and, irrespectively,
to be either transmitted or not during reproduction. The adaptation of the
different schemes for processing variations is quantified for a range of
fluctuating environments, following an approach that links quantitative
genetics with stochastic control theory
SODA: Generating SQL for Business Users
The purpose of data warehouses is to enable business analysts to make better
decisions. Over the years the technology has matured and data warehouses have
become extremely successful. As a consequence, more and more data has been
added to the data warehouses and their schemas have become increasingly
complex. These systems still work great in order to generate pre-canned
reports. However, with their current complexity, they tend to be a poor match
for non tech-savvy business analysts who need answers to ad-hoc queries that
were not anticipated. This paper describes the design, implementation, and
experience of the SODA system (Search over DAta Warehouse). SODA bridges the
gap between the business needs of analysts and the technical complexity of
current data warehouses. SODA enables a Google-like search experience for data
warehouses by taking keyword queries of business users and automatically
generating executable SQL. The key idea is to use a graph pattern matching
algorithm that uses the metadata model of the data warehouse. Our results with
real data from a global player in the financial services industry show that
SODA produces queries with high precision and recall, and makes it much easier
for business users to interactively explore highly-complex data warehouses.Comment: VLDB201
Hierarchy Theory of Evolution and the Extended Evolutionary Synthesis: Some Epistemic Bridges, Some Conceptual Rifts
Contemporary evolutionary biology comprises a plural landscape of multiple co-existent conceptual frameworks and strenuous voices that disagree on the nature and scope of evolutionary theory. Since the mid-eighties, some of these conceptual frameworks have denounced the ontologies of the Modern Synthesis and of the updated Standard Theory of Evolution as unfinished or even flawed. In this paper, we analyze and compare two of those conceptual frameworks, namely Niles Eldredge’s Hierarchy Theory of Evolution (with its extended ontology of evolutionary entities) and the Extended Evolutionary Synthesis (with its proposal of an extended ontology of evolutionary processes), in an attempt to map some epistemic bridges (e.g. compatible views of causation; niche construction) and some conceptual rifts (e.g. extra-genetic inheritance; different perspectives on macroevolution; contrasting standpoints held in the “externalism–internalism” debate) that exist between them. This paper seeks to encourage theoretical, philosophical and historiographical discussions about pluralism or the possible unification of contemporary evolutionary biology
The Extended (Evolutionary) Synthesis Debate: Where Science Meets Philosophy
Recent debates between proponents of the modern evolutionary synthesis (the standard model in evolutionary biology) and those of a possible extended synthesis are a good example of the fascinating tangle among empirical, theoretical, and conceptual or philosophical matters that is the practice of evolutionary biology. In this essay, we briefly discuss two case studies from this debate, highlighting the relevance of philosophical thinking to evolutionary biologists in the hope of spurring further constructive cross-pollination between the two fields
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