9,206 research outputs found

    Replicode: A Constructivist Programming Paradigm and Language

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    Replicode is a language designed to encode short parallel programs and executable models, and is centered on the notions of extensive pattern-matching and dynamic code production. The language is domain independent and has been designed to build systems that are modelbased and model-driven, as production systems that can modify their own code. More over, Replicode supports the distribution of knowledge and computation across clusters of computing nodes. This document describes Replicode and its executive, i.e. the system that executes Replicode constructions. The Replicode executive is meant to run on Linux 64 bits and Windows 7 32/64 bits platforms and interoperate with custom C++ code. The motivations for the Replicode language, the constructivist paradigm it rests on, and the higher-level AI goals targeted by its construction, are described by Thórisson (2012), Nivel and Thórisson (2009), and Thórisson and Nivel (2009a, 2009b). An overview presents the main concepts of the language. Section 3 describes the general structure of Replicode objects and describes pattern matching. Section 4 describes the execution model of Replicode and section 5 describes how computation and knowledge are structured and controlled. Section 6 describes the high-level reasoning facilities offered by the system. Finally, section 7 describes how the computation is distributed over a cluster of computing nodes. Consult Annex 1 for a formal definition of Replicode, Annex 2 for a specification of the executive, Annex 3 for the specification of the executable code format (r-code) and its C++ API, and Annex 4 for the definition of the Replicode Extension C++ API

    Stranger Danger!

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    This article discusses the historical origins of the “stranger danger” myth, including the conditions that fueled the spread of panic. It explains how the myth was bolstered by increased media coverage, emotional appeals by parents, and public awareness campaigns. A number of important terms are defined and statistical information about child abductions in the United States is provided. Constructionist critiques of the “missing children” problem are explored as well as work that looks at the phenomenon through the lens of moral panic. A variety of social, legal, and ethical implications are discussed. The final sections assert the dangers of the myth, explain the difficulties involved in debunking the myth, and argue for the need to shift from fear-based responses to more rational responses that actually work to protect the most vulnerable populations of children (e.g., those who reside in abusive homes or experience harm at the hands of those known to them)

    Motor Output Variability Impairs Driving Ability in Older Adults

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    Background: The functional declines with aging relate to deficits in motor control and strength. In this study, we determine whether older adults exhibit impaired driving as a consequence of declines in motor control or strength. Methods: Young and older adults performed the following tasks: (i) maximum voluntary contractions of ankle dorsiflexion and plantarflexion; (ii) sinusoidal tracking with isolated ankle dorsiflexion; and (iii) a reactive driving task that required responding to unexpected brake lights of the car ahead. We quantified motor control with ankle force variability, gas position variability, and brake force variability. We quantified reactive driving performance with a combination of gas pedal error, premotor and motor response times, and brake pedal error. Results: Reactive driving performance was ~30% more impaired (t = 3.38; p \u3c .01) in older adults compared with young adults. Older adults exhibited greater motor output variability during both isolated ankle dorsiflexion contractions (t = 2.76; p \u3c .05) and reactive driving (gas pedal variability: t = 1.87; p \u3c .03; brake pedal variability: t = 4.55; p \u3c .01). Deficits in reactive driving were strongly correlated to greater motor output variability (R 2 = .48; p \u3c .01) but not strength (p \u3e .05). Conclusions: This study provides novel evidence that age-related declines in motor control but not strength impair reactive driving. These findings have implications on rehabilitation and suggest that interventions should focus on improving motor control to enhance driving-related function in older adults

    ANTICIPATION EFFECT ON KNEE JOINT STABILITY DURING PLANNED AND UN-PLANNED MOVEMENT TESTS IN LABORATORY

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    The purpose of this study was to investigate the anticipation effect on knee stability during functional test in laboratory. Ten healthy male subjects were recruited and instructed to perform a series of planned and un-planned stop-jumping tasks. Knee joint kinematics was measured by a motion analysis system. The subjects demonstrated different abduction and rotation angles for reactive tasks. This suggested that if knee abduction or rotational stability is considered as a primary measurement in documenting knee stability, such as in the investigation of rehabilitation progress after anterior cruciate ligament reconstruction, both planned and un-planned tasks should be considered as to take the anticipation effect into account

    A Review of integrity constraint maintenance and view updating techniques

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    Two interrelated problems may arise when updating a database. On one hand, when an update is applied to the database, integrity constraints may become violated. In such case, the integrity constraint maintenance approach tries to obtain additional updates to keep integrity constraints satisfied. On the other hand, when updates of derived or view facts are requested, a view updating mechanism must be applied to translate the update request into correct updates of the underlying base facts. This survey reviews the research performed on integrity constraint maintenance and view updating. It is proposed a general framework to classify and to compare methods that tackle integrity constraint maintenance and/or view updating. Then, we analyze some of these methods in more detail to identify their actual contribution and the main limitations they may present.Postprint (published version

    Missing Persons Bulletin, Iowa Department of Public Safety, September 2002

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    Monthly newsletter for public safety. Information in this document has been redacted at the request of one of the named individuals. To examine the unedited document, please contact Iowa Library Services / State Library of Iowa – Main Library, 1112 E. Grand Avenue, Des Moines, IA 50319, (515) 242-6542, 1-800-248-4483

    Ultrasound guided glenohumeral injections in adhesive capsulitis

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    Thesis (M.A.)--Boston UniversityObjective: The objective of this thesis was to assess outcomes of glenohumeral corticosteroid injections for adhesive capsulitis. Design: The thesis was composed of two parts. First, a systematic literature review was conducted on glenohumeral corticosteroid injections on shoulder outcomes for adhesive capsulitis. Second, an original prospective study was conducted to measure the effect of ultrasound-guided injections on pain and function for adhesive capsulitis patients. Setting: All injections for the prospective injection study were conducted at Brigham and Women’s Hospital in Boston, MA. Patients: Inclusion criteria were patients receiving an ultrasound guided injection for adhesive capsulitis. 67 patients were included, 59 patients were available at first follow up, and 40 patients were available at final follow up. Methods: The literature review was conducted using the online databases PubMed (1966-present), Embase (1947-present), Web of Science (1900– present), and the Cochrane Central Register of Controlled Trials. Study criteria were limited to clinical trials that evaluated the application of corticosteroid injections, both alone and in combination with other treatment modalities, specifically for the condition of adhesive capsulitis in the shoulder. Studies involving non-corticosteroid injections or injections for conditions not specific to adhesive capsulitis were excluded. Results were limited to papers in the English language. A data table summarizing pain, function, and range of motion outcomes of each treatment was produced. A percent change from baseline was calculated to facilitate comparisons. For the injection study, the first follow-up took place after an average of 2.0 months and patients' improvement in pain and range of motion were assessed. During a final follow-up after an average of 10.4 months, patients’ pain and shoulder function scores were assessed over telephone. [TRUNCATED

    Fast and Continuous Foothold Adaptation for Dynamic Locomotion through CNNs

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    Legged robots can outperform wheeled machines for most navigation tasks across unknown and rough terrains. For such tasks, visual feedback is a fundamental asset to provide robots with terrain-awareness. However, robust dynamic locomotion on difficult terrains with real-time performance guarantees remains a challenge. We present here a real-time, dynamic foothold adaptation strategy based on visual feedback. Our method adjusts the landing position of the feet in a fully reactive manner, using only on-board computers and sensors. The correction is computed and executed continuously along the swing phase trajectory of each leg. To efficiently adapt the landing position, we implement a self-supervised foothold classifier based on a Convolutional Neural Network (CNN). Our method results in an up to 200 times faster computation with respect to the full-blown heuristics. Our goal is to react to visual stimuli from the environment, bridging the gap between blind reactive locomotion and purely vision-based planning strategies. We assess the performance of our method on the dynamic quadruped robot HyQ, executing static and dynamic gaits (at speeds up to 0.5 m/s) in both simulated and real scenarios; the benefit of safe foothold adaptation is clearly demonstrated by the overall robot behavior.Comment: 9 pages, 11 figures. Accepted to RA-L + ICRA 2019, January 201
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