6,705 research outputs found
Applications of artificial intelligence to mission planning
The scheduling problem facing NASA-Marshall mission planning is extremely difficult for several reasons. The most critical factor is the computational complexity involved in developing a schedule. The size of the search space is large along some dimensions and infinite along others. It is because of this and other difficulties that many of the conventional operation research techniques are not feasible or inadequate to solve the problems by themselves. Therefore, the purpose is to examine various artificial intelligence (AI) techniques to assist conventional techniques or to replace them. The specific tasks performed were as follows: (1) to identify mission planning applications for object oriented and rule based programming; (2) to investigate interfacing AI dedicated hardware (Lisp machines) to VAX hardware; (3) to demonstrate how Lisp may be called from within FORTRAN programs; (4) to investigate and report on programming techniques used in some commercial AI shells, such as Knowledge Engineering Environment (KEE); and (5) to study and report on algorithmic methods to reduce complexity as related to AI techniques
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A Combined Tissue Kinetics and Dosimetric Model of Respiratory Tissue Exposed to Radiation
Existing dosimetric models of the radiation response of tissues are essentially static. Consideration of changes in the cell populations over time has not been addressed realistically. For a single acute dose this is not a concern, but for modeling chronic exposures or fractionated acute exposures, the natural turnover and progression of cells could have a significant impact on a variety of endpoints. This proposal addresses the shortcomings of current methods by combining current dose-based calculation techniques with information on the cell turnover for a model tissue. The proposed model will examine effects at the single-cell level for an exposure of a section of human bronchiole. The cell model will be combined with Monte Carlo calculations of doses to cells and cell nuclei due to varying dose-rates of different radiation qualities. Predictions from the model of effects on survival, apoptosis rates, and changes in the number of cycling and differentiating cells will be tested experimentally. The availability of dynamic dosimetric models of tissues at the single-cell level will be useful for analysis of low-level radiation exposures and in the development of new radiotherapy protocols
Diamicton from the Vale of Pickering and Tabular Hills, north-east Yorkshire: evidence for a Middle Pleistocene (MIS 8) glaciation?
Diamicton deposits (up to 6.90 m thick) in the Vale of Pickering and the Tabular Hills (North York Moors) have been confirmed by cored boreholes. The diamicton is interpreted as glacial till with a matrix consisting predominantly of grey-brown, yellow-brown and dark grey, stiff to very stiff clay and sandy clay with occasional thin beds of laminated sand and clay. Sub-rounded to sub-angular erratic clasts were sourced predominantly from local Upper Jurassic Corallian Group bedrock exposed in the southern part of the North York Moors. Clasts include well-rounded, pebbles of Jurassic sandstone, mudstone and sparse Jurassic coal derived from outcrops on the North York Moors. Fragments of underlying Upper Jurassic mudstone bedrock form the predominant clasts in the lower part of the till. The paucity of exotic clasts and a local derivation suggests a relatively small glacier â perhaps a temperate-plateau ice-field, was established on the Tabular Hills. The glacier subsequently advanced southwards to the Vale of Pickering depositing locally derived subglacial traction till at the base, passing up to lodgement till. Local preservation of the degraded till outcrops in the Vale of Pickering, the overconsolidated nature of the clay till matrix, striated pebbles and the presence of sub-rounded pebbles suggests deposition during a glacial cold stage post-MIS 12 (Anglian) and pre-MIS 2 (Devensian). A tentative Middle Pleistocene MIS8 age is proposed, possibly coeval, but not coincident, with the Basement Till (Bridlington Member) of the Holderness coast and the Wragby Till of central and eastern England
Physiological Arousal during Couple Financial Discussions as a Precursor to Seeking Financial Planning Help
There continues to be a great need for financial guidance within American households, yet the utilization of professional financial help, despite its growing accessibility, is low. It has been suggested that physiological arousal is an important factor that influences help-seeking behaviors. This paper tests the hypothesis that help-seeking intentions at the couple level are shaped in part by physiological arousal within the couple. Although exploratory, findings suggest the greater the joint level of arousal, the more likely a couple will be to report an intention to meet with a financial planner. Couples who experience a higher level of arousal during a financial therapy session were found to be more likely to self-report an intention to engage in future financial planning services. Conversely, couples who reported less intention to seek help responded with less arousal during sessions. Implications for financial professionals working with couples are discussed
Assessing Differences Between Physician\u27s Realized And Anticipated Gains From Electronic Health Record Adoption
Return on investment (ROI) concerns related to Electronic Health Records (EHRs) are a major barrier to the technologyâs adoption. Physicians generally rely upon early adopters to vet new technologies prior to putting them into widespread use. Therefore, early adoptersâ experiences with EHRs play a major role in determining future adoption patterns. The paperâs purposes are: (1) to map the EHR value streams that define the ROI calculation; and (2) to compare Current Usersâ and Intended Adoptersâ perceived value streams to identify similarities, differences and governing constructs. Primary data was collected by the Texas Medical Association, which surveyed 1,772 physicians on their use and perceptions of practice gains from EHR adoption. Using Bayesian Belief Network Modeling, value streams are constructed for both current EHR users and Intended Adopters. Current Users and Intended Adopters differ significantly in their perceptions of the EHR value stream. Intended Adoptersâ value stream displays complex relationships among the potential gains compared to the simpler, linear relationship that Current Users identified. The Current Users identify âReduced Medical Records Costsâ as the gain that governs the value stream while Intended Adopters believe âReduced Charge Capture Costsâ define the value streamâs starting point. Current Usersâ versus Intended Adoptersâ assessments of EHR benefits differ significantly and qualitatively from one another
Density matrix operatorial solution of the non--Markovian Master Equation for Quantum Brownian Motion
An original method to exactly solve the non-Markovian Master Equation
describing the interaction of a single harmonic oscillator with a quantum
environment in the weak coupling limit is reported. By using a superoperatorial
approach we succeed in deriving the operatorial solution for the density matrix
of the system. Our method is independent of the physical properties of the
environment. We show the usefulness of our solution deriving explicit
expressions for the dissipative time evolution of some observables of physical
interest for the system, such as, for example, its mean energy.Comment: 16 pages, 1 figur
A Comparison of Survey Methods for Documenting Presence of Myotis leibii (Eastern Small-Footed Bats) at Roosting Areas in Western Virginia
Many aspects of foraging and roosting habitat of Myotis leibii (Eastern Small-Footed Bat), an emergent rock roosting-obligate, are poorly described. Previous comparisons of effectiveness of acoustic sampling and mist-net captures have not included Eastern Small-Footed Bat. Habitat requirements of this species differ from congeners in the region, and it is unclear whether survey protocols developed for other species are applicable. Using data from three overlapping studies at two sampling sites in western Virginiaâs central Appalachian Mountains, detection probabilities were examined for three survey methods (acoustic surveys with automated identification of calls, visual searches of rock crevices, and mist-netting) for use in the development of âbest practicesâ for future surveys and monitoring. Observer effects were investigated using an expanded version of visual search data. Results suggested that acoustic surveys with automated call identification are not effective for documenting presence of Eastern Small-Footed Bats on talus slopes (basal detection rate of 0%) even when the species is known to be present. The broadband, high frequency echolocation calls emitted by Eastern Small-Footed Bat may be prone to attenuation by virtue of their high frequencies, and these factors, along with signal reflection, lower echolocation rates or possible misidentification to other bat species over talus slopes may all have contributed to poor acoustic survey success. Visual searches and mist-netting of emergent rock had basal detection probabilities of 91% and 75%, respectively. Success of visual searches varied among observers, but detection probability improved with practice. Additionally, visual searches were considerably more economical than mist-netting
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