4,933 research outputs found

    A Partial Mechanical Design Compiler

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    I have implemented a simple "mechanical design compiler", that is a program which can convert high-level descriptions of a mechanical design into detail descriptions. (Human interaction is sometimes required.) The program operates in the domain of power transmission equipment composed of discrete, purchasable components. I describe a semantic theory which assigns meanings to the high-level descriptions, and a set of operations on statements in a "specification language" which perform some of the reasoning required by the "compilation" process.MIT Artificial Intelligence Laborator

    Clarifying and expanding the focus of Environmental Toxicology and Chemistry

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92138/1/1869_ftp.pd

    Editorial

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95638/1/2035_ftp.pd

    The Prentice-Hall guide to expert systems : by Robert A. Edmunds, Prentice-Hall, Englewood Cliffs, NJ, 1988, 440 pp.

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29006/1/0000035.pd

    The effects of peer influence on adolescent pedestrian road-crossing decisions

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    Objective: Adolescence is a high-risk period for pedestrian injury. It is also a time of heightened susceptibility to peer influence. The aim of this research was to examine the effects of peer influence on the pedestrian road-crossing decisions of adolescents. Methods: Using 10 videos of road-crossing sites, 80 16- to 18-year-olds were asked to make pedestrian road-crossing decisions. Participants were assigned to one of 4 experimental conditions: negative peer (influencing unsafe decisions), positive peer (influencing cautious decisions), silent peer (who observed but did not comment), and no peer (the participant completed the task alone). Peers from the adolescent’s own friendship group were recruited to influence either an unsafe or a cautious decision. Results: Statistically significant differences were found between peer conditions. Participants least often identified safe road-crossing sites when accompanied by a negative peer and more frequently identified dangerous road-crossing sites when accompanied by a positive peer. Both cautious and unsafe comments from a peer influenced adolescent pedestrians’ decisions. Conclusions: These findings showed that road-crossing decisions of adolescents were influenced by both unsafe and cautious comments from their peers. The discussion highlighted the role that peers can play in both increasing and reducing adolescent risk-taking

    Conceptual robustness in simultaneous engineering: A formulation in continuous spaces

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    This paper develops a robust and distributed decision-making procedure for mathematically modeling and computationally supporting simultaneous decision-making by members of an engineering team. The procedure (1) treats variations in the design posed by other members of the design team as conceptual noise ; (2) incorporates such noise factors into conceptually robust decision-making; (3) provides preference information to other team members on the variables they control; and (4) determines whether to execute the conceptually robust decision or to wait for further design certainty. While Chang et al. (1994) extended Taguchi's approach to such simultaneous decision-making, this paper uses a continuous formulation and discusses the foundations of the procedure in greater detail. The method is demonstrated by a simple distributed design process for a DC motor, and the results are compared with those obtained for the same problem using sequential decision strategies in Krishnan et al. (1991).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45880/1/163_2005_Article_BF01606903.pd

    Shock tunnel studies of scramjet phenomena, supplement 5

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    A series of reports are presented on SCRAMjet studies, shock tunnel studies, and expansion tube studies. The SCRAMjet studies include: (1) Investigation of a Supersonic Combustion Layer; (2) Wall Injected SCRAMjet Experiments; (3) Supersonic Combustion with Transvers, Circular, Wall Jets; (4) Dissociated Test Gas Effects on SCRAMjet Combustors; (5) Use of Silane as a Fuel Additive for Hypersonic Thrust Production, (6) Pressure-length Correlations in Supersonic Combustion; (7) Hot Hydrogen Injection Technique for Shock Tunnels; (8) Heat Release - Wave Interaction Phenomena in Hypersonic Flows; (9) A Study of the Wave Drag in Hypersonic SCRAMjets; (10) Parametric Study of Thrust Production in the Two Dimensional SCRAMjet; (11) The Design of a Mass Spectrometer for use in Hypersonic Impulse Facilities; and (12) Development of a Skin Friction Gauge for use in an Impulse Facility. The shock tunnel studies include: (1) Hypervelocity flow in Axisymmetric Nozzles; (2) Shock Tunnel Development; and (3) Real Gas Efects in Hypervelocity Flows over an Inclined Cone. The expansion tube studies include: (1) Investigation of Flow Characteristics in TQ Expansion Tube; and (2) Disturbances in the Driver Gas of a Shock Tube

    The BRACELET Study: surveys of mortality in UK neonatal and paediatric intensive care trials.

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    BACKGROUND: The subject of death and bereavement in the context of randomised controlled trials in neonatal or paediatric intensive care is under-researched. The objectives of this phase of the Bereavement and RAndomised ControlLEd Trials (BRACELET) Study were to determine trial activity in UK neonatal and paediatric intensive care (2002-06); numbers of deaths before hospital discharge; and variation in mortality across intensive care units and trials and to determine whether bereavement support policies were available within trials. These are essential prerequisites to considering the implications of future policies and practice subsequent to bereavement following a child's enrollment in a trial. METHODS: The units survey involved neonatal units providing level 2 or 3 care, and paediatric units providing level II care or above; the trials survey involved trials where allocation was randomized and interventions were delivered to intensive care patients, or to parents but designed to affect patient outcomes. RESULTS: Information was available from 191/220 (87%) neonatal units (149 level 2 or 3 care); and 28/32 (88%) paediatric units. 90/177 (51%) eligible responding units participated in one or more trial (76 neonatal, 14 paediatric) and 54 neonatal units and 6 paediatric units witnessed at least one death. 50 trials were identified (36 neonatal, 14 paediatric). 3,137 babies were enrolled in neonatal trials, 210 children in paediatric trials. Deaths ranged 0-278 (median [IQR interquartile range] 2 [1, 14.5]) per neonatal trial, 0-4 (median [IQR] 1 [0, 2.5]) per paediatric trial. 534 (16%) participants died post-enrollment: 522 (17%) in neonatal trials, 12 (6%) in paediatric trials. Trial participants ranged 1-236 (median [IQR] 21.5 [8, 39.8]) per neonatal unit, 1-53 (median [IQR] 11.5 [2.3, 33.8]) per paediatric unit. Deaths ranged 0-37 (median [IQR] 3.5 [0.3, 8.8]) per neonatal unit, 0-7 (median [IQR] 0.5 [0, 1.8]) per paediatric unit. Three trials had a formal policy for responding to bereavement. CONCLUSIONS: A substantial number of deaths after trial enrollment were identified, distributed over many trials and units. Few trial teams had responses to bereavement in place. Those with the largest numbers of deaths might be best placed to collaborate in developing and assessing responses to bereavement.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
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