1,233 research outputs found

    Laboratory testing of candidate robotic applications for space

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    Robots have potential for increasing the value of man's presence in space. Some categories with potential benefit are: (1) performing extravehicular tasks like satellite and station servicing, (2) supporting the science mission of the station by manipulating experiment tasks, and (3) performing intravehicular activities which would be boring, tedious, exacting, or otherwise unpleasant for astronauts. An important issue in space robotics is selection of an appropriate level of autonomy. In broad terms three levels of autonomy can be defined: (1) teleoperated - an operator explicitly controls robot movement; (2) telerobotic - an operator controls the robot directly, but by high-level commands, without, for example, detailed control of trajectories; and (3) autonomous - an operator supplies a single high-level command, the robot does all necessary task sequencing and planning to satisfy the command. Researchers chose three projects for their exploration of technology and implementation issues in space robots, one each of the three application areas, each with a different level of autonomy. The projects were: (1) satellite servicing - teleoperated; (2) laboratory assistant - telerobotic; and (3) on-orbit inventory manager - autonomous. These projects are described and some results of testing are summarized

    Investigation of refracting flows for acoustic suppression

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    An experimental investigation to determine the possibility of using refracting flows for the suppression of aircraft inlet noise is described. Observations of wave refraction in duct flows and measurements of the increase in effectiveness of acoustic linings due to refraction have suggested methods for the design of engine inlet ducts which can either suppress noise internally or direct it to where it causes less annoyance

    Methodology for testing and validating knowledge bases

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    A test and validation toolset developed for artificial intelligence programs is described. The basic premises of this method are: (1) knowledge bases have a strongly declarative character and represent mostly structural information about different domains, (2) the conditions for integrity, consistency, and correctness can be transformed into structural properties of knowledge bases, and (3) structural information and structural properties can be uniformly represented by graphs and checked by graph algorithms. The interactive test and validation environment have been implemented on a SUN workstation

    Foundation: Transforming data bases into knowledge bases

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    One approach to transforming information stored in relational data bases into knowledge based representations and back again is described. This system, called Foundation, allows knowledge bases to take advantage of vast amounts of pre-existing data. A benefit of this approach is inspection, and even population, of data bases through an intelligent knowledge-based front-end

    Challenges and implications of routine depression screening for depression in chronic disease and multimorbidity: a cross sectional study

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    <b>Background</b> Depression screening in chronic disease is advocated but its impact on routine practice is uncertain. We examine the effects of a programme of incentivised depression screening in chronic disease within a UK primary care setting.<p></p> <b>Methods and Findings</b> Cross sectional analysis of anonymised, routinely collected data (for 2008-9) from family practices in Scotland serving a population of circa 1.8 million. Patients registered in primary care with at least one of three chronic diseases, coronary heart disease, diabetes and stroke, underwent incentivised depression screening using the Hospital Anxiety and Depression Score (HADS). <p></p> 125143 patients were identified with at least one chronic disease. 10670 (8.5%) were under treatment for depression and exempt from screening. Of the remaining, HADS were recorded for 35537 (31.1%) patients. 7080 (19.9% of screened) had raised HADS (≥8); the majority had indications of mild depression with a HADS between 8 and 10. Over 6 months, 572 (8%) of those with a raised HADS (≥8) were initiated on antidepressants, while 696 (2.4%) patients with a normal HADS (<8) were also initiated on antidepressants (relative risk of antidepressant initiation with raised HADS 3.3 (CI 2.97-3.67), p value <0.0001). Of those with multimorbidity who were screened, 24.3% had a raised HADS (≥8). A raised HADS was more likely in females, socioeconomically deprived, multimorbid or younger (18-44) individuals. Females and 45-64 years old were more likely to receive antidepressants.<p></p> <b>Limitations</b> – retrospective study of routinely collected data.<p></p> <b>Conclusions </b> Despite incentivisation, only minority of patients underwent depression screening, suggesting that systematic depression screening in chronic disease can be difficult to achieve in routine practice. Targeting those at greatest risk such as the multimorbid or using simpler screening methods may be more effective. Raised HADS was associated with a higher number of new antidepressant prescriptions which has significant resource implications. The clinical benefits of such screening remain uncertain and merit investigation

    Graphical explanation in an expert system for Space Station Freedom rack integration

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    The rationale and methodology used to incorporate graphics into explanations provided by an expert system for Space Station Freedom rack integration is examined. The rack integration task is typical of a class of constraint satisfaction problems for large programs where expertise from several areas is required. Graphically oriented approaches are used to explain the conclusions made by the system, the knowledge base content, and even at more abstract levels the control strategies employed by the system. The implemented architecture combines hypermedia and inference engine capabilities. The advantages of this architecture include: closer integration of user interface, explanation system, and knowledge base; the ability to embed links to deeper knowledge underlying the compiled knowledge used in the knowledge base; and allowing for more direct control of explanation depth and duration by the user. The graphical techniques employed range from simple statis presentation of schematics to dynamic creation of a series of pictures presented motion picture style. User models control the type, amount, and order of information presented

    Design Knowledge Capture: Preserving Engineering Knowledge For Future Applications

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    A new problem beginning to challenge the artificial intelligence community is design knowledge capture. There has been an increased desire to construct systems with inherent built-in evolvability toward more advanced technologies and machine intelligence. Success in this evolution process depends on being able to capture as-built design knowledge from the outset. Requirements and objectives for such systems are reviewed and an application to capture design knowledge within a combined data and knowledge environment is presented. Design knowledge and rationale are implemented as design objects. Knowledge represented within an object can be physical, conceptual, functional, or structural. Storage and retrieval of rationale is achieved through a network of design objects and a model of the design process. The context, as well as the content, of captured knowledge is described within the process network of requirements, trades, and analyses. Design knowledge applications include, for example, traceability to requirements, standards, and specifications. It can be used to describe attributes of a part, or for input to further analyses, and trade studies. Other uses include verification, simulation, and maintenance activities

    The structure of benzylidene alpha methylglucoside and of 2:3 dimethylglucose

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    After discussing the condensation portion of methylglucoside with benzaldehyde and the chemistry of the product, the structure of benzylidene methylglucoside, together with that of the dimethyl glucose, is reviewed. A few observations upon the effect of the substitutions upon the molecular rotation of methylglucoside is then inserted before an account is given of the chemical behaviour of dimethyl glucose, as contrasted with that of the unsubstituted sugar. Finally, the experiments on which the Thesis is based, prefaced by notes explaining the technique adopted, complete the work
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