Distributed cognition: cognizing, autonomy and the Turing Test

Some of the papers in this Special Issue distribute cognition between what is going on inside individual cognizers’ heads and their outside worlds; others distribute cognition among different individual cognizers. Turing’s criterion for cognition was for individual, autonomous input/output capacity. It is not clear that distributed cognition could pass the Turing Tes

Feature Selection via Coalitional Game Theory

We present and study the contribution-selection algorithm (CSA), a novel algorithm for feature selection. The algorithm is based on the multiperturbation shapley analysis (MSA), a framework that relies on game theory to estimate usefulness. The algorithm iteratively estimates the usefulness of features and selects them accordingly, using either forward selection or backward elimination. It can optimize various performance measures over unseen data such as accuracy, balanced error rate, and area under receiver-operator-characteristic curve. Empirical comparison with several other existing feature selection methods shows that the backward elimination variant of CSA leads to the most accurate classification results on an array of data sets

Decision making under time pressure: an independent test of sequential sampling models

Choice probability and choice response time data from a risk-taking decision-making task were compared with predictions made by a sequential sampling model. The behavioral data, consistent with the model, showed that participants were less likely to take an action as risk levels increased, and that time pressure did not have a uniform effect on choice probability. Under time pressure, participants were more conservative at the lower risk levels but were more prone to take risks at the higher levels of risk. This crossover interaction reflected a reduction of the threshold within a single decision strategy rather than a switching of decision strategies. Response time data, as predicted by the model, showed that participants took more time to make decisions at the moderate risk levels and that time pressure reduced response time across all risk levels, but particularly at the those risk levels that took longer time with no pressure. Finally, response time data were used to rule out the hypothesis that time pressure effects could be explained by a fast-guess strategy

Making training more cognitively effective: making videos interactive

The cost of health and safety (H&S) failures to the UK industry is currently estimated at up to £6.5 billion per annum, with the construction sector suffering unacceptably high levels of work-related incidents. Better H&S education across all skill levels in the industry is seen as an integral part of any solution. Traditional lecture-based courses often fail to recreate the dynamic realities of managing H&S on site and therefore do not sufficiently create deeper cognitive learning (which results in remembering and using what was learned). The use of videos is a move forward, but passively observing a video is not cognitively engaging and challenging, and therefore learning is not as effective as it can be. This paper describes the development of an interactive video in which learners take an active role. While observing the video, they are required to engage, participate, respond and be actively involved. The potential for this approach to be used in conjunction with more traditional approaches to H&S was explored using a group of 2nd-year undergraduate civil engineering students. The formative results suggested that the learning experience could be enhanced using interactive videos. Nevertheless, most of the learners believed that a blended approach would be most effective

Brown representability for space-valued functors

In this paper we prove two theorems which resemble the classical cohomological and homological Brown representability theorems. The main difference is that our results classify small contravariant functors from spaces to spaces up to weak equivalence of functors. In more detail, we show that every small contravariant functor from spaces to spaces which takes coproducts to products up to homotopy and takes homotopy pushouts to homotopy pullbacks is naturally weekly equivalent to a representable functor. The second representability theorem states: every contravariant continuous functor from the category of finite simplicial sets to simplicial sets taking homotopy pushouts to homotopy pullbacks is equivalent to the restriction of a representable functor. This theorem may be considered as a contravariant analog of Goodwillie's classification of linear functors.Comment: 19 pages, final version, accepted by the Israel Journal of Mathematic

Using a neural network approach for muon reconstruction and triggering

The extremely high rate of events that will be produced in the future Large Hadron Collider requires the triggering mechanism to take precise decisions in a few nano-seconds. We present a study which used an artificial neural network triggering algorithm and compared it to the performance of a dedicated electronic muon triggering system. Relatively simple architecture was used to solve a complicated inverse problem. A comparison with a realistic example of the ATLAS first level trigger simulation was in favour of the neural network. A similar architecture trained after the simulation of the electronics first trigger stage showed a further background rejection.Comment: A talk given at ACAT03, KEK, Japan, November 2003. Submitted to Nuclear Instruments and Methods in Physics Research, Section

Spectral signatures of modulated d-wave superconducting phases

We calculate within a mean-field theory the spectral signatures of various striped d-wave superconducting phases. We consider both in-phase and anti-phase modulations of the superconducting order across a stripe boundary, and the effects of coexisting inhomogeneous orders, including spin stripes, charge stripes, and modulated d-density-wave. We find that the anti-phase modulated d-wave superconductor exhibits zero-energy spectral weight, primarily along extended arcs in momentum space. Concomitantly, a Fermi surface appears and typically includes both open segments and closed pockets. When weak homogeneous superconductivity is also present the Fermi surface collapses onto nodal points. Among them are the nodal points of the homogeneous d-wave superconductor, but others typically exist at positions which depend on the details of the modulation and the band structure. Upon increasing the amplitude of the constant component these additional points move towards the edges of the reduced Brillouin zone where they eventually disappear. The above signatures are also manifested in the density of states of the clean, and the disordered system. While the presence of coexisting orders changes some details of the spectral function, we find that the evolution of the Fermi-surface and the distribution of the low-energy spectral weight are largely unaffected by them.Comment: Published version. We added an appendix including the detailed Hamiltonians, and made other minor change