2,472 research outputs found

    Satellite-aided mobile communications limited operational test in the trucking industry

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    An experiment with NASA's ATS-6 satellite, that demonstrates the practicality of satellite-aided land mobile communications is described. Satellite communications equipment for the experiment was designed so that it would be no more expensive, when mass produced, than conventional two-way mobile radio equipment. It embodied the operational features and convenience of present day mobile radios. Vehicle antennas 75 cm tall and 2 cm in diameter provided good commercial quality signals to and from trucks and jeeps. Operational applicability and usage data were gathered by installing the radio equipment in five long-haul tractor-trailer trucks and two Air Force search and rescue jeeps. Channel occupancy rates are reported. Air Force personnel found the satellite radio system extremely valuable in their search and rescue mission during maneuvers and actual rescue operations. Propagation data is subjectively analyzed and over 4 hours of random data is categorized and graded as to signal quality on a second by second basis. Trends in different topographic regions are reported. An overall communications reliability of 93% was observed despite low satellite elevation angles ranging from 9 to 24 degrees

    Position surveillance using one active ranging satellite and time-of-arrival of a signal from an independent satellite

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    Position surveillance using one active ranging/communication satellite and the time-of-arrival of signals from an independent satellite was shown to be feasible and practical. A towboat on the Mississippi River was equipped with a tone-code ranging transponder and a receiver tuned to the timing signals of the GOES satellite. A similar transponder was located at the office of the towing company. Tone-code ranging interrogations were transmitted from the General Electric Earth Station Laboratory through ATS-6 to the towboat and to the ground truth transponder office. Their automatic responses included digital transmissions of time-of-arrival measurements derived from the GOES signals. The Earth Station Laboratory determined ranges from the satellites to the towboat and computed position fixes. The ATS-6 lines-of-position were more precise than 0.1 NMi, 1 sigma, and the GOES lines-of-position were more precise than 1.6 NMi, 1 sigma. High quality voice communications were accomplished with the transponders using a nondirectional antenna on the towboat. The simple and effective surveillance technique merits further evaluation using operational maritime satellites

    Enhancing caBIG™ workflow for multi-tier distribution

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    posterIntroduction caBIG™ Integration caBIG™ provides a GRID based application environment with data abstraction and vocabulary services, workflow management and a security framework. Sensor Abstraction Interface It is proposed to provide a sensor abstraction interface, using caDSR, enabling caBIG™ workflow aware applications to obtain local and global access to sensor data. Applications from any caGRID accessible node will be able to utilize the collected data. Example Application We have chosen a disaster scenario using radiation level sensors to illustrate how sensors mounted in static facilities and first responder vehicles can be relayed via an adhoc wireless network to various hospital or government facilities. Data can be analyzed locally, for local planning and health care provisioning purposes, or accessed via the GRID by a hierarchy of city, county, state, and federal agencies. Application Hierarchy Proposed architecture is designed to use existing low cost infrastructure as a highly resilient mechanism for relaying sensor data. The network will piggy-back on the first responder networking systems and the applications layer will utilize caBIG™ services

    ca! - emergency and disaster recovery system extensions to caBIG™

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    posterDuring Hurricane Katrina, US Federal and State Agencies had disparate data acquisition systems, separate data networks and unique incompatible applications. •System incompatibilities exist even between various Federal agencies. •Consistent data available to one agency should be available to another. Data must be portable and with a common vocabulary. •Katrina illustrated the need for a common data system to underpin applications at the first responder, local medical facility and state health care department level, plus federal safety and law enforcement

    The use of happiness research for public policy

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    Research on happiness tends to follow a "benevolent dictator" approach where politicians pursue people's happiness. This paper takes an antithetic approach based on the insights of public choice theory. First, we inquire how the results of happiness research may be used to improve the choice of institutions. Second, we show that the policy approach matters for the choice of research questions and the kind of knowledge happiness research aims to provide. Third, we emphasize that there is no shortcut to an optimal policy maximizing some happiness indicator or social welfare function since governments have an incentive to manipulate this indicator

    Institutional and technological barriers to the use of open educational resources (OERs) in physiology and medical education

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    Open educational resources (OERs) are becoming increasingly common as a tool in education, particularly in medical and biomedical education. However, three key barriers have been identified to their use: (i) lack of awareness of OERs, (ii) lack of motivation to use OERs, and (iii) lack of training in the use of OERs. Here, we explore these three barriers with teachers of medical and biomedical science to establish how best to enhance the use of OERs to improve pedagogical outcomes. An online survey was completed by 209 educators, many of whom (68.4%) reported using OERs in their teaching, and almost all (99.5%) showing awareness of at least one OER. Results suggest that key problems that prevent educators from adopting OERs in their teaching include suitability for particular classes, time, and copyright. Most (81.8%) educators were somewhat, very, or extremely comfortable with OERs so there is no innate motivational barrier to adoption. A lack of training was reported by 13.9% of respondents, and 40% of respondents stated that there was little or no support from their institutions. OER users were no more comfortable with technology or better supported by departments, but tended to be aware of a greater number of sources of OERs. Our study illustrates key opportunities for the expansion of OER use in physiology and medical teaching: increased breadth of awareness, increased institutional support (including time, training, and copyright support), and greater sharing of diverse OERs to suit the range of teaching challenges faced by staff in different subdisciplines

    Data Mining for Gene Networks Relevant to Poor Prognosis in Lung Cancer Via Backward-Chaining Rule Induction

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    We use Backward Chaining Rule Induction (BCRI), a novel data mining method for hypothesizing causative mechanisms, to mine lung cancer gene expression array data for mechanisms that could impact survival. Initially, a supervised learning system is used to generate a prediction model in the form of “IF <conditions> THEN <outcome>” style rules. Next, each antecedent (i.e. an IF condition) of a previously discovered rule becomes the outcome class for subsequent application of supervised rule induction. This step is repeated until a termination condition is satisfied. “Chains” of rules are created by working backward from an initial condition (e.g. survival status). Through this iterative process of “backward chaining,” BCRI searches for rules that describe plausible gene interactions for subsequent validation. Thus, BCRI is a semi-supervised approach that constrains the search through the vast space of plausible causal mechanisms by using a top-level outcome to kick-start the process. We demonstrate the general BCRI task sequence, how to implement it, the validation process, and how BCRI-rules discovered from lung cancer microarray data can be combined with prior knowledge to generate hypotheses about functional genomics

    Organization of the magnetosphere during substorms

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    The change in degree of organization of the magnetosphere during substorms is investigated by analyzing various geomagnetic indices, as well as interplanetary magnetic field z-component and solar wind flow speed. We conclude that the magnetosphere self-organizes globally during substorms, but neither the magnetosphere nor the solar wind become more predictable in the course of a substorm. This conclusion is based on analysis of five hundred substorms in the period from 2000 to 2002. A minimal dynamic-stochastic model of the driven magnetosphere that reproduces many statistical features of substorm indices is discussed
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