118,291 research outputs found

    Diffusion-based neuromodulation can eliminate catastrophic forgetting in simple neural networks

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    A long-term goal of AI is to produce agents that can learn a diversity of skills throughout their lifetimes and continuously improve those skills via experience. A longstanding obstacle towards that goal is catastrophic forgetting, which is when learning new information erases previously learned information. Catastrophic forgetting occurs in artificial neural networks (ANNs), which have fueled most recent advances in AI. A recent paper proposed that catastrophic forgetting in ANNs can be reduced by promoting modularity, which can limit forgetting by isolating task information to specific clusters of nodes and connections (functional modules). While the prior work did show that modular ANNs suffered less from catastrophic forgetting, it was not able to produce ANNs that possessed task-specific functional modules, thereby leaving the main theory regarding modularity and forgetting untested. We introduce diffusion-based neuromodulation, which simulates the release of diffusing, neuromodulatory chemicals within an ANN that can modulate (i.e. up or down regulate) learning in a spatial region. On the simple diagnostic problem from the prior work, diffusion-based neuromodulation 1) induces task-specific learning in groups of nodes and connections (task-specific localized learning), which 2) produces functional modules for each subtask, and 3) yields higher performance by eliminating catastrophic forgetting. Overall, our results suggest that diffusion-based neuromodulation promotes task-specific localized learning and functional modularity, which can help solve the challenging, but important problem of catastrophic forgetting

    IMEX evolution of scalar fields on curved backgrounds

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    Inspiral of binary black holes occurs over a time-scale of many orbits, far longer than the dynamical time-scale of the individual black holes. Explicit evolutions of a binary system therefore require excessively many time steps to capture interesting dynamics. We present a strategy to overcome the Courant-Friedrichs-Lewy condition in such evolutions, one relying on modern implicit-explicit ODE solvers and multidomain spectral methods for elliptic equations. Our analysis considers the model problem of a forced scalar field propagating on a generic curved background. Nevertheless, we encounter and address a number of issues pertinent to the binary black hole problem in full general relativity. Specializing to the Schwarzschild geometry in Kerr-Schild coordinates, we document the results of several numerical experiments testing our strategy.Comment: 28 pages, uses revtex4. Revised in response to referee's report. One numerical experiment added which incorporates perturbed initial data and adaptive time-steppin

    Investigating invariant item ordering in the Mental Health Inventory : an illustration of the use of different methods

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    Invariant item ordering is a property of scales whereby the items are scored in the same order across a wide range of the latent trait and across a wide range of respondents. In the package ‘mokken’ in the statistical software R, the ability to analyse Mokken scales for invariant item ordering has recently been available and techniques for inspecting visually the item response curves of item pairs, have also been included. While methods to assess invariant item ordering are available, there have been indications that items representing extremes of distress in mental well-being scales, such as suicidal ideation, may lead to claiming invariant item ordering where it does not exist. We used the Mental Health Inventory to see if invariant item ordering was indicated in any Mokken scales derived and to see if this was being influenced by extreme items. A Mokken scale was derived indicating invariant item ordering. Visual inspection of the item pairs indicated that the most difficult item (suicidal ideation) was located far from the remaining cluster of items. Removing this item lowered invariant item ordering to an unacceptable level

    Granting People Safety: GPS Tracking for Domestic Violence Offenders

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    Old School Catalog 1904-05, Annual Catalog

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    https://scholar.valpo.edu/oldschoolcatalogs/1036/thumbnail.jp

    How to Solve an Allocation Problem?

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    Game theory proposes several allocation solutions: we know (a) fairness properties, (b) how to develop (c) methods building on these properties, and (d) how to calculate (e) allocations. We also know how to influence the perceived fairness and realization of allocation solutions. However, we cannot explain properly that theoretically fair allocation methods are rarely used.\ud To obtain more insight into these issues we solved an allocation problem in a purchasing cooperative case study by confronting theory with perceptions. We find large theoretical and perception differences and inconsistencies between and within the five steps from a to e. We note that theoretically fair methods tend to be more complex than theoretically unfair methods. In addition, the allocations of some simple methods are perceived fairer than the allocations of complex methods in our case study. To improve theoretical solutions the focus should be on a and c. To influence perceptions the focus should be on b, c, and d. Finally, all five steps are modeled into comparable fairness measures and a general model. Using this model implies that both theory and perceptions are considered in solving allocation problems

    Old School Catalog 1905-06, Annual Catalog

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    https://scholar.valpo.edu/oldschoolcatalogs/1034/thumbnail.jp

    The New Ice Age: Addressing the Deficiencies in Arkansas\u27s Posthumously Conceived Children Statute

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    The ability to conceive a child using the preserved genetic material, or gametes, of a deceased person presents a number of legal issues for inheritance, estate planning, Social Security, and parental rights. New medical advancements in assisted reproductive technology (ART) enable individuals to conceive children after their death, complicating the conventional methods of determining heirship of the decedent under state intestacy laws. The purpose of intestacy law is to determine the succession of a decedent that dies without a will, or intestate, with the goal of carrying out the donative intent of the decedent. Intestacy law has failed to keep pace with these technological advancements, which has left the legal status of posthumously conceived children (PCC) uncertain in many states
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