1,351 research outputs found

    Early Globus Pallidus Internus Stimulation in Pediatric Patients With Generalized Primary Dystonia: Long-Term Efficacy and Safety

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    Primary generalized dystonia presents mainly at a young age and commonly is severely disabling. The authors report the long-term follow-up (mean, 73 months; range, 50-101 months) of 5 pediatric patients (mean age at surgery 13 years; range, 8-16 years) undergoing globus pallidus internus deep brain stimulation. Mean improvement in the Burke-Fahn-Marsden movement score was 67.4% (range, 47.0%-87.5%), 75.4% (range, 61.5%-91.7%), and 83.5% (range, 72.0%-93.3%) at 3 months, 12 months, and long-term follow-up (>36 months), respectively. Hardware problems (electrode dislocation/breakage of extension cable, and imminent perforation of extension cable) were observed in 2 patients (operative revision without sequelae). Except for mild dysarthria in 2 patients, no other therapy-related morbidity was observed. The authors found globus pallidus internus stimulation to offer a very effective and safe therapy in pediatric patients with primary dystonia. Early neurosurgical intervention seems to be crucial to prevent irreversible impairment of motor function

    Analysis of airplane boarding via space-time geometry and random matrix theory

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    We show that airplane boarding can be asymptotically modeled by 2-dimensional Lorentzian geometry. Boarding time is given by the maximal proper time among curves in the model. Discrepancies between the model and simulation results are closely related to random matrix theory. We then show how such models can be used to explain why some commonly practiced airline boarding policies are ineffective and even detrimental.Comment: 4 page

    Case-Based Reasoning Systems: From Automation to Decision-Aiding and Stimulation

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    Over the past decade, case-based reasoning (CBR) has emerged as a major research area within the artificial intelligence research field due to both its widespread usage by humans and its appeal as a methodology for building intelligent systems. Conventional CBR systems have been largely designed as automated problem-solvers for producing a solution to a given problem by adapting the solution to a similar, previously solved problem. Such systems have had limited success in real-world applications. More recently, there has been a search for new paradigms and directions for increasing the utility of CBR systems for decision support. This paper focuses on the synergism between the research areas of CBR and decision support systems (DSSs). A conceptual framework for DSSs is presented and used to develop a taxonomy of three different types of CBR systems: 1) conventional, 2) decision-aiding, and 3) stimulative. The major characteristics of each type of CBR system are explained with a particular focus on decision-aiding and stimulative CBR systems. The research implications of the evolution in the design of CBR systems from automation toward decision-aiding and stimulation are also explored

    Continuous modelling of machine tool failure durations for improved production scheduling

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    Unforeseen machine tool failures due to technical issues can cause downtimes leading to delays during production. To reduce delays, rescheduling of the production is, in most cases, necessary. However, warranting such a change requires reliable knowledge about the duration of the failure. This article presents a method to provide this knowledge by estimating the duration of a machine tool failure based on previous failure durations. Using the cross-industry standard process for data mining (CRISP-DM) and statistical methods, the embedded model for failure classification and duration is continuously improved. The method is thoroughly tested using multiple distributions, parameters and a practical use case. The results show high potential for predicting the duration of machine tool failures, which consequently could lead to improved quality of rescheduling. © 2020, The Author(s)

    Fixed parameter tractable algorithms in combinatorial topology

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    To enumerate 3-manifold triangulations with a given property, one typically begins with a set of potential face pairing graphs (also known as dual 1-skeletons), and then attempts to flesh each graph out into full triangulations using an exponential-time enumeration. However, asymptotically most graphs do not result in any 3-manifold triangulation, which leads to significant "wasted time" in topological enumeration algorithms. Here we give a new algorithm to determine whether a given face pairing graph supports any 3-manifold triangulation, and show this to be fixed parameter tractable in the treewidth of the graph. We extend this result to a "meta-theorem" by defining a broad class of properties of triangulations, each with a corresponding fixed parameter tractable existence algorithm. We explicitly implement this algorithm in the most generic setting, and we identify heuristics that in practice are seen to mitigate the large constants that so often occur in parameterised complexity, highlighting the practicality of our techniques.Comment: 16 pages, 9 figure
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