2,795 research outputs found

    Logic, self-awareness and self-improvement: The metacognitive loop and the problem of brittleness

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    This essay describes a general approach to building perturbation-tolerant autonomous systems, based on the conviction that artificial agents should be able notice when something is amiss, assess the anomaly, and guide a solution into place. We call this basic strategy of self-guided learning the metacognitive loop; it involves the system monitoring, reasoning about, and, when necessary, altering its own decision-making components. In this essay, we (a) argue that equipping agents with a metacognitive loop can help to overcome the brittleness problem, (b) detail the metacognitive loop and its relation to our ongoing work on time-sensitive commonsense reasoning, (c) describe specific, implemented systems whose perturbation tolerance was improved by adding a metacognitive loop, and (d) outline both short-term and long-term research agendas

    Small linearly equivalent GG-sets and a construction of Beaulieu

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    Two GG-sets (GG a finite group) are called linearly equivalent over a commutative ring kk if the permutation representations k[X]k[X] and k[Y]k[Y] are isomorphic as modules over the group algebra kGkG. Pairs of linearly equivalent non-isomorphic GG-sets have applications in number theory and geometry. We characterize the groups GG for which such pairs exist for any field, and give a simple construction of these pairs. If kk is \Q, these are precisely the non-cyclic groups. For any non-cyclic group, we prove that there exist GG-sets which are non-isomorphic and \lineq over \Q, of cardinality \leq 3(#G)/2. Also, we investigate a construction of P. Beaulieu which allows us to construct pairs of transitive linearly equivalent SnS_n-sets from arbitrary GG-sets for an arbitrary group GG. We show that this construction works over all fields and use it construct, for each finite set \mc P of primes, SnS_n-sets linearly equivalent over a field kk if and only if the characteristic of kk lies in \mc P.Comment: v2: fixed proof of Lemma 2.

    The roots of self-awareness

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    In this paper we provide an account of the structural underpinnings of self-awareness. We offer both an abstract, logical account-by way of suggestions for how to build a genuinely self-referring artificial agent-and a biological account, via a discussion of the role of somatoception in supporting and structuring self-awareness more generally. Central to the account is a discussion of the necessary motivational properties of self-representing mental tokens, in light of which we offer a novel definition of self-representation. We also discuss the role of such tokens in organizing self-specifying information, which leads to a naturalized restatement of the guarantee that introspective awareness is immune to error due to mis-identification of the subject

    desire: a case study

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    Renormalization in general theories with inter-generation mixing

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    We derive general and explicit expressions for the unrenormalized and renormalized dressed propagators of fermions in parity-nonconserving theories with inter-generation mixing. The mass eigenvalues, the corresponding mass counterterms, and the effect of inter-generation mixing on their determination are discussed. Invoking the Aoki-Hioki-Kawabe-Konuma-Muta renormalization conditions and employing a number of very useful relations from Matrix Algebra, we show explicitly that the renormalized dressed propagators satisfy important physical properties.Comment: 14 pages; to appear in Phys. Rev.

    The Natural History of Insomnia: Acute Insomnia and First-onset Depression

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    Study Objectives: While many studies have examined the association between insomnia and depression, no studies have evaluated these associations 1) within a narrow time frame, 2) with specific reference to acute & chronic insomnia, and 3) using polysomnography. In the present study, the association between insomnia and first-onset depression was evaluated taking into account these considerations. Design: A mixed-model inception design. Setting: Academic research laboratory. Participants: Fifty-four individuals (acute insomnia (n=33), normal sleepers (n=21)) with no reported history of a sleep disorder, chronic medical condition, or psychiatric illness. Interventions: N/A Measurements and Results: Participants were assessed at baseline (two nights of polysomnography and psychometric measures of stress and mood) and insomnia and depression status were reassessed at 3 months. Individuals with acute insomnia exhibited more stress, poorer mood, worse subjective sleep continuity, increased N2 sleep and decreased N3 sleep. Individuals that transitioned to chronic insomnia exhibited (at baseline) shorter REM Latencies and reduced N3 sleep. Individuals that exhibited this pattern, in the transition from acute to chronic insomnia, were also more likely to develop first-onset depression (9.26%) as compared to those who remitted from insomnia (1.85%) or were normal sleepers (1.85%). Conclusion: The transition from acute to chronic insomnia is presaged by baseline differences in sleep architecture that have, in the past, been ascribed to Major Depression, either as heritable traits or as acquired traits from prior episodes of depression. The present findings suggest that the “sleep architecture stigmata” of depression may actually develop over the course transitioning from acute to chronic insomnia

    Introduction to the Special Review Issue

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    Editorial Note

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    Feynman Propagator for a Free Scalar Field on a Causal Set

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    The Feynman propagator for a free bosonic scalar field on the discrete spacetime of a causal set is presented. The formalism includes scalar field operators and a vacuum state which define a scalar quantum field theory on a causal set. This work can be viewed as a novel regularisation of quantum field theory based on a Lorentz invariant discretisation of spacetime.Comment: 4 pages, 2 plots. Minor updates to match published versio
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