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Sample records for cognettia sphagnetorum adapt

  1. Adaptation.

    PubMed

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  2. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  3. Enchytraeids and microbes in Zn polluted soil: no link between organism-level stress responses and ecosystem functioning.

    PubMed

    Salminen, J; Anh, B T; Van Gestel, C A

    2001-12-01

    We studied the presence of zinc tolerance in enchytraeid worm (Cognettia sphagnetorum, Oligochaeta) from a metal-polluted forest soil in The Netherlands. In a dose response experiment, we compared Zn sensitivity, measured as body growth and reproduction, of these enchytraeids with that of animals taken from three unpolluted sites. Because C. sphagnetorum is a keystone species, regulating microbial processes in coniferous forest soil, we performed a microcosm experiment to study the interaction of enchytraeids from several sites with soil microbes. The idea was to study whether there is a link between metal stress response of individuals (tolerance level, life history alteration) and changes observed at higher organization levels of the biological system (trophic interaction and decomposition processes). We did not find evidence for increased metal tolerance of C. sphagnetorum. Worms from the polluted site actually had reduced body growth, indicating negative fitness effects caused by long-lasting metal stress. The density and biomass of the worm population from the polluted site was low in Zn contaminated soil. Presence of enchytraeids enhanced and Zn contamination reduced the activity of microbes in the soil. Enchytraeids from different sites with different life histories and population development, however, had the same effect on microbes. Hence, observed stress responses of individuals and populations could not be linked to density-dependent trophic interactions and ecosystem functioning in the soil-decomposer food chain.

  4. Visual Adaptation

    PubMed Central

    Webster, Michael A.

    2015-01-01

    Sensory systems continuously mold themselves to the widely varying contexts in which they must operate. Studies of these adaptations have played a long and central role in vision science. In part this is because the specific adaptations remain a powerful tool for dissecting vision, by exposing the mechanisms that are adapting. That is, “if it adapts, it's there.” Many insights about vision have come from using adaptation in this way, as a method. A second important trend has been the realization that the processes of adaptation are themselves essential to how vision works, and thus are likely to operate at all levels. That is, “if it's there, it adapts.” This has focused interest on the mechanisms of adaptation as the target rather than the probe. Together both approaches have led to an emerging insight of adaptation as a fundamental and ubiquitous coding strategy impacting all aspects of how we see. PMID:26858985

  5. Adaptive Management

    EPA Science Inventory

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive managem...

  6. Adaptive Management

    EPA Science Inventory

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive managem...

  7. Adaptive SPECT

    PubMed Central

    Barrett, Harrison H.; Furenlid, Lars R.; Freed, Melanie; Hesterman, Jacob Y.; Kupinski, Matthew A.; Clarkson, Eric; Whitaker, Meredith K.

    2008-01-01

    Adaptive imaging systems alter their data-acquisition configuration or protocol in response to the image information received. An adaptive pinhole single-photon emission computed tomography (SPECT) system might acquire an initial scout image to obtain preliminary information about the radiotracer distribution and then adjust the configuration or sizes of the pinholes, the magnifications, or the projection angles in order to improve performance. This paper briefly describes two small-animal SPECT systems that allow this flexibility and then presents a framework for evaluating adaptive systems in general, and adaptive SPECT systems in particular. The evaluation is in terms of the performance of linear observers on detection or estimation tasks. Expressions are derived for the ideal linear (Hotelling) observer and the ideal linear (Wiener) estimator with adaptive imaging. Detailed expressions for the performance figures of merit are given, and possible adaptation rules are discussed. PMID:18541485

  8. Climate adaptation

    NASA Astrophysics Data System (ADS)

    Kinzig, Ann P.

    2015-03-01

    This paper is intended as a brief introduction to climate adaptation in a conference devoted otherwise to the physics of sustainable energy. Whereas mitigation involves measures to reduce the probability of a potential event, such as climate change, adaptation refers to actions that lessen the impact of climate change. Mitigation and adaptation differ in other ways as well. Adaptation does not necessarily have to be implemented immediately to be effective; it only needs to be in place before the threat arrives. Also, adaptation does not necessarily require global, coordinated action; many effective adaptation actions can be local. Some urban communities, because of land-use change and the urban heat-island effect, currently face changes similar to some expected under climate change, such as changes in water availability, heat-related morbidity, or changes in disease patterns. Concern over those impacts might motivate the implementation of measures that would also help in climate adaptation, despite skepticism among some policy makers about anthropogenic global warming. Studies of ancient civilizations in the southwestern US lends some insight into factors that may or may not be important to successful adaptation.

  9. Cold adaptations.

    PubMed

    Launay, Jean-Claude; Savourey, Gustave

    2009-07-01

    Nowdays, occupational and recreational activities in cold environments are common. Exposure to cold induces thermoregulatory responses like changes of behaviour and physiological adjustments to maintain thermal balance either by increasing metabolic heat production by shivering and/or by decreasing heat losses consecutive to peripheral cutaneous vasoconstriction. Those physiological responses present a great variability among individuals and depend mainly on biometrical characteristics, age, and general cold adaptation. During severe cold exposure, medical disorders may occur such as accidental hypothermia and/or freezing or non-freezing cold injuries. General cold adaptations have been qualitatively classified by Hammel and quantitatively by Savourey. This last classification takes into account the quantitative changes of the main cold reactions: higher or lower metabolic heat production, higher or lesser heat losses and finally the level of the core temperature observed at the end of a standardized exposure to cold. General cold adaptations observed previously in natives could also be developed in laboratory conditions by continuous or intermittent cold exposures. Beside general cold adaptation, local cold adaptation exists and is characterized by a lesser decrease of skin temperature, a more pronounced cold induced vasodilation, less pain and a higher manual dexterity. Adaptations to cold may reduce the occurrence of accidents and improve human performance as surviving in the cold. The present review describes both general and local cold adaptations in humans and how they are of interest for cold workers.

  10. Toothbrush Adaptations.

    ERIC Educational Resources Information Center

    Exceptional Parent, 1987

    1987-01-01

    Suggestions are presented for helping disabled individuals learn to use or adapt toothbrushes for proper dental care. A directory lists dental health instructional materials available from various organizations. (CB)

  11. Adaptive management

    USGS Publications Warehouse

    Allen, Craig R.; Garmestani, Ahjond S.

    2015-01-01

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive management has explicit structure, including a careful elucidation of goals, identification of alternative management objectives and hypotheses of causation, and procedures for the collection of data followed by evaluation and reiteration. The process is iterative, and serves to reduce uncertainty, build knowledge and improve management over time in a goal-oriented and structured process.

  12. Adaptive Thresholds

    SciTech Connect

    Bremer, P. -T.

    2014-08-26

    ADAPT is a topological analysis code that allow to compute local threshold, in particular relevance based thresholds for features defined in scalar fields. The initial target application is vortex detection but the software is more generally applicable to all threshold based feature definitions.

  13. Adaptation of adaptive optics systems.

    NASA Astrophysics Data System (ADS)

    Xin, Yu; Zhao, Dazun; Li, Chen

    1997-10-01

    In the paper, a concept of an adaptation of adaptive optical system (AAOS) is proposed. The AAOS has certain real time optimization ability against the variation of the brightness of detected objects m, atmospheric coherence length rO and atmospheric time constant τ by means of changing subaperture number and diameter, dynamic range, and system's temporal response. The necessity of AAOS using a Hartmann-Shack wavefront sensor and some technical approaches are discussed. Scheme and simulation of an AAOS with variable subaperture ability by use of both hardware and software are presented as an example of the system.

  14. Connector adapter

    NASA Technical Reports Server (NTRS)

    Hacker, Scott C. (Inventor); Dean, Richard J. (Inventor); Burge, Scott W. (Inventor); Dartez, Toby W. (Inventor)

    2007-01-01

    An adapter for installing a connector to a terminal post, wherein the connector is attached to a cable, is presented. In an embodiment, the adapter is comprised of an elongated collet member having a longitudinal axis comprised of a first collet member end, a second collet member end, an outer collet member surface, and an inner collet member surface. The inner collet member surface at the first collet member end is used to engage the connector. The outer collet member surface at the first collet member end is tapered for a predetermined first length at a predetermined taper angle. The collet includes a longitudinal slot that extends along the longitudinal axis initiating at the first collet member end for a predetermined second length. The first collet member end is formed of a predetermined number of sections segregated by a predetermined number of channels and the longitudinal slot.

  15. Adaptive equalization

    NASA Astrophysics Data System (ADS)

    Qureshi, S. U. H.

    1985-09-01

    Theoretical work which has been effective in improving data transmission by telephone and radio links using adaptive equalization (AE) techniques is reviewed. AE has been applied to reducing the temporal dispersion effects, such as intersymbol interference, caused by the channel accessed. Attention is given to the Nyquist telegraph transmission theory, least mean square error adaptive filtering and the theory and structure of linear receive and transmit filters for reducing error. Optimum nonlinear receiver structures are discussed in terms of optimality criteria as a function of error probability. A suboptimum receiver structure is explored in the form of a decision-feedback equalizer. Consideration is also given to quadrature amplitude modulation and transversal equalization for receivers.

  16. Adaptive sampler

    DOEpatents

    Watson, B.L.; Aeby, I.

    1980-08-26

    An adaptive data compression device for compressing data is described. The device has a frequency content, including a plurality of digital filters for analyzing the content of the data over a plurality of frequency regions, a memory, and a control logic circuit for generating a variable rate memory clock corresponding to the analyzed frequency content of the data in the frequency region and for clocking the data into the memory in response to the variable rate memory clock.

  17. Adaptive sampler

    DOEpatents

    Watson, Bobby L.; Aeby, Ian

    1982-01-01

    An adaptive data compression device for compressing data having variable frequency content, including a plurality of digital filters for analyzing the content of the data over a plurality of frequency regions, a memory, and a control logic circuit for generating a variable rate memory clock corresponding to the analyzed frequency content of the data in the frequency region and for clocking the data into the memory in response to the variable rate memory clock.

  18. Adaptive antennas

    NASA Astrophysics Data System (ADS)

    Barton, P.

    1987-04-01

    The basic principles of adaptive antennas are outlined in terms of the Wiener-Hopf expression for maximizing signal to noise ratio in an arbitrary noise environment; the analogy with generalized matched filter theory provides a useful aid to understanding. For many applications, there is insufficient information to achieve the above solution and thus non-optimum constrained null steering algorithms are also described, together with a summary of methods for preventing wanted signals being nulled by the adaptive system. The three generic approaches to adaptive weight control are discussed; correlation steepest descent, weight perturbation and direct solutions based on sample matrix conversion. The tradeoffs between hardware complexity and performance in terms of null depth and convergence rate are outlined. The sidelobe cancellor technique is described. Performance variation with jammer power and angular distribution is summarized and the key performance limitations identified. The configuration and performance characteristics of both multiple beam and phase scan array antennas are covered, with a brief discussion of performance factors.

  19. DARK ADAPTATION IN DINEUTES

    PubMed Central

    Clark, Leonard B.

    1938-01-01

    The level of dark adaptation of the whirligig beetle can be measured in terms of the threshold intensity calling forth a response. The course of dark adaptation was determined at levels of light adaptation of 6.5, 91.6, and 6100 foot-candles. All data can be fitted by the same curve. This indicates that dark adaptation follows parts of the same course irrespective of the level of light adaptation. The intensity of the adapting light determines the level at which dark adaptation will begin. The relation between log aI0 (instantaneous threshold) and log of adapting light intensity is linear over the range studied. PMID:19873056

  20. Adaptive Image Denoising by Mixture Adaptation.

    PubMed

    Luo, Enming; Chan, Stanley H; Nguyen, Truong Q

    2016-10-01

    We propose an adaptive learning procedure to learn patch-based image priors for image denoising. The new algorithm, called the expectation-maximization (EM) adaptation, takes a generic prior learned from a generic external database and adapts it to the noisy image to generate a specific prior. Different from existing methods that combine internal and external statistics in ad hoc ways, the proposed algorithm is rigorously derived from a Bayesian hyper-prior perspective. There are two contributions of this paper. First, we provide full derivation of the EM adaptation algorithm and demonstrate methods to improve the computational complexity. Second, in the absence of the latent clean image, we show how EM adaptation can be modified based on pre-filtering. The experimental results show that the proposed adaptation algorithm yields consistently better denoising results than the one without adaptation and is superior to several state-of-the-art algorithms.

  1. Adaptive Image Denoising by Mixture Adaptation

    NASA Astrophysics Data System (ADS)

    Luo, Enming; Chan, Stanley H.; Nguyen, Truong Q.

    2016-10-01

    We propose an adaptive learning procedure to learn patch-based image priors for image denoising. The new algorithm, called the Expectation-Maximization (EM) adaptation, takes a generic prior learned from a generic external database and adapts it to the noisy image to generate a specific prior. Different from existing methods that combine internal and external statistics in ad-hoc ways, the proposed algorithm is rigorously derived from a Bayesian hyper-prior perspective. There are two contributions of this paper: First, we provide full derivation of the EM adaptation algorithm and demonstrate methods to improve the computational complexity. Second, in the absence of the latent clean image, we show how EM adaptation can be modified based on pre-filtering. Experimental results show that the proposed adaptation algorithm yields consistently better denoising results than the one without adaptation and is superior to several state-of-the-art algorithms.

  2. Adaptation illustrations: Chapter 4

    Treesearch

    Maria Janowiak; Patricia Butler; Chris Swanston; Matt St. Pierre; Linda. Parker

    2012-01-01

    In this chapter, we demonstrate how the Adaptation Workbook (Chapter 3) can be used with the Adaptation Strategies and Approaches (Chapter 2) to develop adaptation tactics for two real-world management issues. The two illustrations in this chapter are intended to provide helpful tips to managers completing the Adaptation Workbook, as well as to show how the anticipated...

  3. Habituation of visual adaptation

    PubMed Central

    Dong, Xue; Gao, Yi; Lv, Lili; Bao, Min

    2016-01-01

    Our sensory system adjusts its function driven by both shorter-term (e.g. adaptation) and longer-term (e.g. learning) experiences. Most past adaptation literature focuses on short-term adaptation. Only recently researchers have begun to investigate how adaptation changes over a span of days. This question is important, since in real life many environmental changes stretch over multiple days or longer. However, the answer to the question remains largely unclear. Here we addressed this issue by tracking perceptual bias (also known as aftereffect) induced by motion or contrast adaptation across multiple daily adaptation sessions. Aftereffects were measured every day after adaptation, which corresponded to the degree of adaptation on each day. For passively viewed adapters, repeated adaptation attenuated aftereffects. Once adapters were presented with an attentional task, aftereffects could either reduce for easy tasks, or initially show an increase followed by a later decrease for demanding tasks. Quantitative analysis of the decay rates in contrast adaptation showed that repeated exposure of the adapter appeared to be equivalent to adaptation to a weaker stimulus. These results suggest that both attention and a non-attentional habituation-like mechanism jointly determine how adaptation develops across multiple daily sessions. PMID:26739917

  4. Population dynamics and vertical distribution of enchytraeids and tardigrades in response to deforestation

    NASA Astrophysics Data System (ADS)

    Uhía, E.; Briones, M. J. I.

    2002-12-01

    In order to increase our present knowledge of the potential impacts of deforestation on the soil ecosystem, we investigated the responses of enchytraeid and tardigrade populations to tree harvesting. The study was conducted in an area of ca. 10 ha located at an altitude of approximately 450 m in the surroundings of the University campus (Vigo, Pontevedra, Spain). Pine forest ( Pinus pinaster Aiton), with an average density of 400 trees/ha ranging between 10 and 20 years of age, and some young oaks ( Quercus robur L.) were covering the area. At the end of the summer 1995, approximately 50% of the area was harvested. Soil and animal samples were taken from May 1996 to April 1997 at monthly intervals in both forested and deforested areas. Removal of the trees resulted in a significant effect on enchytraeid population numbers and their response was species-dependent in terms of changes in both population numbers and vertical distribution. Higher mortality rates of enchytraeids were recorded in the absence of trees. August seemed to have been critical for survival of all enchytraeid species as no individuals were found in that month and only a few recovered in the following month. Only Cognettia sphagnetorum showed vertical migration in order to avoid adverse conditions. Tardigrades were more abundant in the deforested areas; their ability to enter in a resistant stage could have enabled them to overcome adverse environmental conditions. It is concluded that harvesting of the trees has changed the soil environment and that differences in moisture and temperature conditions are not sufficient to explain the observed differences. The forest soils contained more organic matter than those in the deforested area and therefore differences in the amount and/or quality of the organic matter could be one of the possible explanations for the observed changes in enchytraeid abundance when the forest is removed.

  5. Expressing Adaptation Strategies Using Adaptation Patterns

    ERIC Educational Resources Information Center

    Zemirline, N.; Bourda, Y.; Reynaud, C.

    2012-01-01

    Today, there is a real challenge to enable personalized access to information. Several systems have been proposed to address this challenge including Adaptive Hypermedia Systems (AHSs). However, the specification of adaptation strategies remains a difficult task for creators of such systems. In this paper, we consider the problem of the definition…

  6. Expressing Adaptation Strategies Using Adaptation Patterns

    ERIC Educational Resources Information Center

    Zemirline, N.; Bourda, Y.; Reynaud, C.

    2012-01-01

    Today, there is a real challenge to enable personalized access to information. Several systems have been proposed to address this challenge including Adaptive Hypermedia Systems (AHSs). However, the specification of adaptation strategies remains a difficult task for creators of such systems. In this paper, we consider the problem of the definition…

  7. Adaptation and Cultural Diffusion.

    ERIC Educational Resources Information Center

    Ormrod, Richard K.

    1992-01-01

    Explores the role of adaptation in cultural diffusion. Explains that adaptation theory recognizes the lack of independence between innovations and their environmental settings. Discusses testing and selection, modification, motivation, and cognition. Suggests that adaptation effects are pervasive in cultural diffusion but require a broader, more…

  8. Adapting to climate change

    Treesearch

    Constance I. Millar; Christopher W. Swanston; David L. Peterson

    2014-01-01

    Federal agencies have led the development of adaptation principles and tools in forest ecosystems over the past decade. Successful adaptation efforts generally require organizations to: (1) develop science-management partnerships, (2) provide education on climate change science, (3) provide a toolkit of methods and processes for vulnerability assessment and adaptation...

  9. Resilience through adaptation

    PubMed Central

    van Voorn, George A. K.; Ligtenberg, Arend; Molenaar, Jaap

    2017-01-01

    Adaptation of agents through learning or evolution is an important component of the resilience of Complex Adaptive Systems (CAS). Without adaptation, the flexibility of such systems to cope with outside pressures would be much lower. To study the capabilities of CAS to adapt, social simulations with agent-based models (ABMs) provide a helpful tool. However, the value of ABMs for studying adaptation depends on the availability of methodologies for sensitivity analysis that can quantify resilience and adaptation in ABMs. In this paper we propose a sensitivity analysis methodology that is based on comparing time-dependent probability density functions of output of ABMs with and without agent adaptation. The differences between the probability density functions are quantified by the so-called earth-mover’s distance. We use this sensitivity analysis methodology to quantify the probability of occurrence of critical transitions and other long-term effects of agent adaptation. To test the potential of this new approach, it is used to analyse the resilience of an ABM of adaptive agents competing for a common-pool resource. Adaptation is shown to contribute positively to the resilience of this ABM. If adaptation proceeds sufficiently fast, it may delay or avert the collapse of this system. PMID:28196372

  10. Organizational Adaptation and Higher Education.

    ERIC Educational Resources Information Center

    Cameron, Kim S.

    1984-01-01

    Organizational adaptation and types of adaptation needed in academe in the future are reviewed and major conceptual approaches to organizational adaptation are presented. The probable environment that institutions will face in the future that will require adaptation is discussed. (MLW)

  11. Human heat adaptation.

    PubMed

    Taylor, Nigel A S

    2014-01-01

    In this overview, human morphological and functional adaptations during naturally and artificially induced heat adaptation are explored. Through discussions of adaptation theory and practice, a theoretical basis is constructed for evaluating heat adaptation. It will be argued that some adaptations are specific to the treatment used, while others are generalized. Regarding ethnic differences in heat tolerance, the case is put that reported differences in heat tolerance are not due to natural selection, but can be explained on the basis of variations in adaptation opportunity. These concepts are expanded to illustrate how traditional heat adaptation and acclimatization represent forms of habituation, and thermal clamping (controlled hyperthermia) is proposed as a superior model for mechanistic research. Indeed, this technique has led to questioning the perceived wisdom of body-fluid changes, such as the expansion and subsequent decay of plasma volume, and sudomotor function, including sweat habituation and redistribution. Throughout, this contribution was aimed at taking another step toward understanding the phenomenon of heat adaptation and stimulating future research. In this regard, research questions are posed concerning the influence that variations in morphological configuration may exert upon adaptation, the determinants of postexercise plasma volume recovery, and the physiological mechanisms that modify the cholinergic sensitivity of sweat glands, and changes in basal metabolic rate and body core temperature following adaptation. © 2014 American Physiological Society.

  12. Gravitational adaptation of animals

    NASA Technical Reports Server (NTRS)

    Smith, A. H.; Burton, R. R.

    1982-01-01

    The effect of gravitational adaptation is studied in a group of five Leghorn cocks which had become physiologically adapted to 2 G after 162 days of centrifugation. After this period of adaptation, they are periodically exposed to a 2 G field, accompanied by five previously unexposed hatch-mates, and the degree of retained acceleration adaptation is estimated from the decrease in lymphocyte frequency after 24 hr at 2 G. Results show that the previously adapted birds exhibit an 84% greater lymphopenia than the unexposed birds, and that the lymphocyte frequency does not decrease to a level below that found at the end of 162 days at 2 G. In addition, the capacity for adaptation to chronic acceleration is found to be highly heritable. An acceleration tolerant strain of birds shows lesser mortality during chronic acceleration, particularly in intermediate fields, although the result of acceleration selection is largely quantitative (a greater number of survivors) rather than qualitative (behavioral or physiological changes).

  13. Origins of adaptive immunity.

    PubMed

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity.

  14. Technology transfer for adaptation

    NASA Astrophysics Data System (ADS)

    Biagini, Bonizella; Kuhl, Laura; Gallagher, Kelly Sims; Ortiz, Claudia

    2014-09-01

    Technology alone will not be able to solve adaptation challenges, but it is likely to play an important role. As a result of the role of technology in adaptation and the importance of international collaboration for climate change, technology transfer for adaptation is a critical but understudied issue. Through an analysis of Global Environment Facility-managed adaptation projects, we find there is significantly more technology transfer occurring in adaptation projects than might be expected given the pessimistic rhetoric surrounding technology transfer for adaptation. Most projects focused on demonstration and early deployment/niche formation for existing technologies rather than earlier stages of innovation, which is understandable considering the pilot nature of the projects. Key challenges for the transfer process, including technology selection and appropriateness under climate change, markets and access to technology, and diffusion strategies are discussed in more detail.

  15. Parallel Anisotropic Tetrahedral Adaptation

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Darmofal, David L.

    2008-01-01

    An adaptive method that robustly produces high aspect ratio tetrahedra to a general 3D metric specification without introducing hybrid semi-structured regions is presented. The elemental operators and higher-level logic is described with their respective domain-decomposed parallelizations. An anisotropic tetrahedral grid adaptation scheme is demonstrated for 1000-1 stretching for a simple cube geometry. This form of adaptation is applicable to more complex domain boundaries via a cut-cell approach as demonstrated by a parallel 3D supersonic simulation of a complex fighter aircraft. To avoid the assumptions and approximations required to form a metric to specify adaptation, an approach is introduced that directly evaluates interpolation error. The grid is adapted to reduce and equidistribute this interpolation error calculation without the use of an intervening anisotropic metric. Direct interpolation error adaptation is illustrated for 1D and 3D domains.

  16. Molecular Adaptation during a Rapid Adaptive Radiation

    PubMed Central

    Kapralov, Maxim V.; Votintseva, Antonina A.; Filatov, Dmitry A.

    2013-01-01

    “Explosive” adaptive radiations on islands remain one of the most puzzling evolutionary phenomena and the evolutionary genetic processes behind such radiations remain unclear. Rapid morphological and ecological evolution during island radiations suggests that many genes may be under fairly strong selection, although this remains untested. Here, we report that during a rapid recent diversification in the Hawaiian endemic plant genus Schiedea (Caryophyllaceae), 5 in 36 studied genes evolved under positive selection. Positively selected genes are involved in defence mechanisms, photosynthesis, and reproduction. Comparison with eight mainland plant groups demonstrates both the relaxation of purifying selection and more widespread positive selection in Hawaiian Schiedea. This provides compelling evidence that adaptive evolution of protein-coding genes may play a significant role during island adaptive radiations. PMID:23355532

  17. Adaptation as organism design

    PubMed Central

    Gardner, Andy

    2009-01-01

    The problem of adaptation is to explain the apparent design of organisms. Darwin solved this problem with the theory of natural selection. However, population geneticists, whose responsibility it is to formalize evolutionary theory, have long neglected the link between natural selection and organismal design. Here, I review the major historical developments in theory of organismal adaptation, clarifying what adaptation is and what it is not, and I point out future avenues for research. PMID:19793739

  18. Quantifying the adaptive cycle

    USGS Publications Warehouse

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  19. The purpose of adaptation.

    PubMed

    Gardner, Andy

    2017-10-06

    A central feature of Darwin's theory of natural selection is that it explains the purpose of biological adaptation. Here, I: emphasize the scientific importance of understanding what adaptations are for, in terms of facilitating the derivation of empirically testable predictions; discuss the population genetical basis for Darwin's theory of the purpose of adaptation, with reference to Fisher's 'fundamental theorem of natural selection'; and show that a deeper understanding of the purpose of adaptation is achieved in the context of social evolution, with reference to inclusive fitness and superorganisms.

  20. Adaptation and visual salience

    PubMed Central

    McDermott, Kyle C.; Malkoc, Gokhan; Mulligan, Jeffrey B.; Webster, Michael A.

    2011-01-01

    We examined how the salience of color is affected by adaptation to different color distributions. Observers searched for a color target on a dense background of distractors varying along different directions in color space. Prior adaptation to the backgrounds enhanced search on the same background while adaptation to orthogonal background directions slowed detection. Advantages of adaptation were seen for both contrast adaptation (to different color axes) and chromatic adaptation (to different mean chromaticities). Control experiments, including analyses of eye movements during the search, suggest that these aftereffects are unlikely to reflect simple learning or changes in search strategies on familiar backgrounds, and instead result from how adaptation alters the relative salience of the target and background colors. Comparable effects were observed along different axes in the chromatic plane or for axes defined by different combinations of luminance and chromatic contrast, consistent with visual search and adaptation mediated by multiple color mechanisms. Similar effects also occurred for color distributions characteristic of natural environments with strongly selective color gamuts. Our results are consistent with the hypothesis that adaptation may play an important functional role in highlighting the salience of novel stimuli by discounting ambient properties of the visual environment. PMID:21106682

  1. Quantifying the Adaptive Cycle.

    PubMed

    Angeler, David G; Allen, Craig R; Garmestani, Ahjond S; Gunderson, Lance H; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  2. Human adaptation to smog

    SciTech Connect

    Evans, G.W. Jacobs, S.V.; Frager, N.B.

    1982-10-01

    This study examined the health effects of human adaptation to photochemical smog. A group of recent arrivals to the Los Angeles air basin were compared to long-term residents of the basin. Evidence for adaptation included greater irritation and respiratory problems among the recent arrivals and desensitization among the long-term residents in their judgments of the severity of the smog problem to their health. There was no evidence for biochemical adaptation as measured by hemoglobin response to oxidant challenge. The results were discussed in terms of psychological adaption to chronic environmental stressors.

  3. Adaptive parallel logic networks

    NASA Technical Reports Server (NTRS)

    Martinez, Tony R.; Vidal, Jacques J.

    1988-01-01

    Adaptive, self-organizing concurrent systems (ASOCS) that combine self-organization with massive parallelism for such applications as adaptive logic devices, robotics, process control, and system malfunction management, are presently discussed. In ASOCS, an adaptive network composed of many simple computing elements operating in combinational and asynchronous fashion is used and problems are specified by presenting if-then rules to the system in the form of Boolean conjunctions. During data processing, which is a different operational phase from adaptation, the network acts as a parallel hardware circuit.

  4. Physiologic adaptation to space - Space adaptation syndrome

    NASA Technical Reports Server (NTRS)

    Vanderploeg, J. M.

    1985-01-01

    The adaptive changes of the neurovestibular system to microgravity, which result in space motion sickness (SMS), are studied. A list of symptoms, which range from vomiting to drowsiness, is provided. The two patterns of symptom development, rapid and gradual, and the duration of the symptoms are described. The concept of sensory conflict and rearrangements to explain SMS is being investigated.

  5. Uncertainty in adaptive capacity

    NASA Astrophysics Data System (ADS)

    Adger, W. Neil; Vincent, Katharine

    2005-03-01

    The capacity to adapt is a critical element of the process of adaptation: it is the vector of resources that represent the asset base from which adaptation actions can be made. Adaptive capacity can in theory be identified and measured at various scales, from the individual to the nation. The assessment of uncertainty within such measures comes from the contested knowledge domain and theories surrounding the nature of the determinants of adaptive capacity and the human action of adaptation. While generic adaptive capacity at the national level, for example, is often postulated as being dependent on health, governance and political rights, and literacy, and economic well-being, the determinants of these variables at national levels are not widely understood. We outline the nature of this uncertainty for the major elements of adaptive capacity and illustrate these issues with the example of a social vulnerability index for countries in Africa. To cite this article: W.N. Adger, K. Vincent, C. R. Geoscience 337 (2005).

  6. Water Resource Adaptation Program

    EPA Science Inventory

    The Water Resource Adaptation Program (WRAP) contributes to the U.S. Environmental Protection Agency’s (U.S. EPA) efforts to provide water resource managers and decision makers with the tools needed to adapt water resources to demographic and economic development, and future clim...

  7. Electrochromic Adaptive Infrared Camouflage

    DTIC Science & Technology

    2005-12-01

    Electrochromic Adaptive Infrared Camouflage Interim Progress Report Eli Yablonovitch Period covered: August 1999...August 1999 - January 2005 4. TITLE AND SUBTITLE Electrochromic Adaptive Infrared Camouflage 5. FUNDING NUMBERS DAAD19-99-1-0316...emissivity is made possible by electrochromics . Today, electrochromics is becoming a common technology that is used, for example, in self-dimming

  8. Management for adaptation

    Treesearch

    John Innes; Linda A. Joyce; Seppo Kellomaki; Bastiaan Louman; Aynslie Ogden; John Parrotta; Ian Thompson; Matthew Ayres; Chin Ong; Heru Santoso; Brent Sohngen; Anita Wreford

    2009-01-01

    This chapter develops a framework to explore examples of adaptation options that could be used to ensure that the ecosystem services provided by forests are maintained under future climates. The services are divided into broad areas within which managers can identify specific management goals for individual forests or landscapes. Adaptation options exist for the major...

  9. Research, Adaptation, & Change.

    ERIC Educational Resources Information Center

    Morris, Lee A., Ed.; And Others

    Research adaptation is an endeavor that implies solid collaboration among school practitioners and university and college researchers. This volume addresses the broad issues of research as an educational endeavor, adaptation as a necessary function associated with applying research findings to school situations, and change as an inevitable…

  10. Evolution: Sex Limits Adaptation.

    PubMed

    Nosil, Patrik

    2015-07-20

    Evolution is affected by survival of individuals and by mate choice, but how sexual selection affects adaptation remains unclear. A new study finds that sexual selection can limit adaptation by causing male-induced harm to females and thus opposing natural selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Speededness and Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Xiong, Xinhui

    2013-01-01

    Two simple constraints on the item parameters in a response--time model are proposed to control the speededness of an adaptive test. As the constraints are additive, they can easily be included in the constraint set for a shadow-test approach (STA) to adaptive testing. Alternatively, a simple heuristic is presented to control speededness in plain…

  12. Retinal Imaging: Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Goncharov, A. S.; Iroshnikov, N. G.; Larichev, Andrey V.

    This chapter describes several factors influencing the performance of ophthalmic diagnostic systems with adaptive optics compensation of human eye aberration. Particular attention is paid to speckle modulation, temporal behavior of aberrations, and anisoplanatic effects. The implementation of a fundus camera with adaptive optics is considered.

  13. Computerized Adaptive Ability Measurement.

    ERIC Educational Resources Information Center

    Weiss, David J.

    The general objective of a research program on adaptive testing was to identify several sources of potential error in test scores, and to study adaptive testing as a means for reducing these errors. Errors can result from the mismatch of item difficulty to the individual's ability; the psychological effects of testing and the test environment; the…

  14. Adaptation to astigmatic blur

    PubMed Central

    Sawides, Lucie; Marcos, Susana; Ravikumar, Sowmya; Thibos, Larry; Bradley, Arthur; Webster, Michael

    2011-01-01

    Adapting to blurred or sharpened images alters the perceived focus of subsequently viewed images. We examined whether these adaptation effects could arise from actual sphero-cylindrical refractive errors, by testing aftereffects in images simulating second-order astigmatism. Image blur was varied from negative (vertical) through isotropic to positive (horizontal) astigmatism while maintaining constant blur strength. A 2AFC staircase was used to estimate the stimulus that appeared isotropically blurred before or after adapting to images with astigmatism. Adaptation to horizontal blur caused isotropically blurred images to appear vertically biased and vice versa, shifting the perceived isotropic point toward the adapting level. Aftereffects were similar for different types of images and showed partial selectivity so that strongest effects generally occurred when testing and adapting images were the same. Further experiments explored whether the adaptation depended more strongly on the blurring or “fuzziness” in the images vs. the apparent “figural” changes introduced by the blur, by comparing how the aftereffects transfer across changes in size or orientation. Our results suggest that strong selective adaptation can occur for different lower order aberrations of the eye and that these may be at least partly driven by the apparent figural changes that blurring introduces into the retinal image. PMID:21047754

  15. Research, Adaptation, & Change.

    ERIC Educational Resources Information Center

    Morris, Lee A., Ed.; And Others

    Research adaptation is an endeavor that implies solid collaboration among school practitioners and university and college researchers. This volume addresses the broad issues of research as an educational endeavor, adaptation as a necessary function associated with applying research findings to school situations, and change as an inevitable…

  16. Water Resource Adaptation Program

    EPA Science Inventory

    The Water Resource Adaptation Program (WRAP) contributes to the U.S. Environmental Protection Agency’s (U.S. EPA) efforts to provide water resource managers and decision makers with the tools needed to adapt water resources to demographic and economic development, and future clim...

  17. On Teaching Adaptively

    ERIC Educational Resources Information Center

    Corno, Lyn

    2008-01-01

    New theory on adaptive teaching reflects the social dynamics of classrooms to explain what practicing teachers do to address student differences related to learning. In teaching adaptively, teachers respond to learners as they work. Teachers read student signals to diagnose needs on the fly and tap previous experience with similar learners to…

  18. Adaptive Wavelet Transforms

    SciTech Connect

    Szu, H.; Hsu, C.

    1996-12-31

    Human sensors systems (HSS) may be approximately described as an adaptive or self-learning version of the Wavelet Transforms (WT) that are capable to learn from several input-output associative pairs of suitable transform mother wavelets. Such an Adaptive WT (AWT) is a redundant combination of mother wavelets to either represent or classify inputs.

  19. Turbine system and adapter

    DOEpatents

    Hogberg, Nicholas Alvin; Garcia-Crespo, Andres Jose

    2017-05-30

    A turbine system and adapter are disclosed. The adapter includes a turbine attachment portion having a first geometry arranged to receive a corresponding geometry of a wheelpost of a turbine rotor, and a bucket attachment portion having a second geometry arranged to receive a corresponding geometry of a root portion of a non-metallic turbine bucket. Another adapter includes a turbine attachment portion arranged to receive a plurality of wheelposts of a turbine rotor, and a bucket attachment portion arranged to receive a plurality of non-metallic turbine buckets having single dovetail configuration root portions. The turbine system includes a turbine rotor wheel configured to receive metal buckets, at least one adapter secured to at least one wheelpost on the turbine rotor wheel, and at least one non-metallic bucket secured to the at least one adapter.

  20. Adaptive signal processor

    SciTech Connect

    Walz, H.V.

    1980-07-01

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 ..mu..sec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed.

  1. Financing climate change adaptation.

    PubMed

    Bouwer, Laurens M; Aerts, Jeroen C J H

    2006-03-01

    This paper examines the topic of financing adaptation in future climate change policies. A major question is whether adaptation in developing countries should be financed under the 1992 United Nations Framework Convention on Climate Change (UNFCCC), or whether funding should come from other sources. We present an overview of financial resources and propose the employment of a two-track approach: one track that attempts to secure climate change adaptation funding under the UNFCCC; and a second track that improves mainstreaming of climate risk management in development efforts. Developed countries would need to demonstrate much greater commitment to the funding of adaptation measures if the UNFCCC were to cover a substantial part of the costs. The mainstreaming of climate change adaptation could follow a risk management path, particularly in relation to disaster risk reduction. 'Climate-proofing' of development projects that currently do not consider climate and weather risks could improve their sustainability.

  2. 75 FR 57859 - Specially Adapted Housing and Special Home Adaptation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-23

    ... AFFAIRS 38 CFR Part 3 RIN 2900-AN21 Specially Adapted Housing and Special Home Adaptation AGENCY... housing and special home adaptation grants. This final rule incorporates certain provisions from the... adapted housing (SAH) grants and special home adaptation (SHA) grants. The public comment period ended on...

  3. Dynamical Adaptation in Photoreceptors

    PubMed Central

    Clark, Damon A.; Benichou, Raphael; Meister, Markus; Azeredo da Silveira, Rava

    2013-01-01

    Adaptation is at the heart of sensation and nowhere is it more salient than in early visual processing. Light adaptation in photoreceptors is doubly dynamical: it depends upon the temporal structure of the input and it affects the temporal structure of the response. We introduce a non-linear dynamical adaptation model of photoreceptors. It is simple enough that it can be solved exactly and simulated with ease; analytical and numerical approaches combined provide both intuition on the behavior of dynamical adaptation and quantitative results to be compared with data. Yet the model is rich enough to capture intricate phenomenology. First, we show that it reproduces the known phenomenology of light response and short-term adaptation. Second, we present new recordings and demonstrate that the model reproduces cone response with great precision. Third, we derive a number of predictions on the response of photoreceptors to sophisticated stimuli such as periodic inputs, various forms of flickering inputs, and natural inputs. In particular, we demonstrate that photoreceptors undergo rapid adaptation of response gain and time scale, over ∼ 300 ms—i. e., over the time scale of the response itself—and we confirm this prediction with data. For natural inputs, this fast adaptation can modulate the response gain more than tenfold and is hence physiologically relevant. PMID:24244119

  4. Adaptation to blur

    NASA Astrophysics Data System (ADS)

    Webster, Michael A.; Webster, Shernaaz M.; MacDonald, Jennifer; Bahradwadj, Shrikant R.

    2001-06-01

    Blur is an intrinsic property of the retinal image that can vary substantially in natural viewing. We examined how processes of contrast adaptation might adjust the visual system to regulate the perception of blur. Observers viewed a blurred or sharpened image for 2-5 minutes, and then judged the apparent focus of a series of 0.5-sec test images interleaved with 6-sec of readaptation. A 2AFC staircase procedure was used to vary the amplitude spectrum of successive test to find the image that appeared in focus. Adapting to a blurred image causes a physically focused image to appear too sharp. Opposite after-effects occur for sharpened adapting images. Pronounced biases were observed over a wide range of magnitudes of adapting blur, and were similar for different types of blur. After-effects were also similar for different classes of images but were generally weaker when the adapting and test stimuli were different images, showing that the adaptation is not adjusting simply to blur per se. These adaptive adjustments may strongly influence the perception of blur in normal vision and how it changes with refractive errors.

  5. Adaptive clinical trial design.

    PubMed

    Chow, Shein-Chung

    2014-01-01

    In recent years, the use of adaptive design methods in clinical trials based on accumulated data at interim has received much attention because of its flexibility and efficiency in pharmaceutical/clinical development. In practice, adaptive design may provide the investigators a second chance to modify or redesign the trial while the study is still ongoing. However, it is a concern that a shift in target patient population may occur after significant adaptations are made. In addition, the overall type I error rate may not be preserved. Moreover, the results may not be reliable and hence are difficult to interpret. As indicated by the US Food and Drug Administration draft guidance on adaptive design clinical trials, the adaptive design has to be a prospectively planned opportunity and should be based on information collected within the study, with or without formal statistical hypothesis testing. This article reviews the relative advantages, limitations, and feasibility of commonly considered adaptive designs in clinical trials. Statistical concerns when implementing adaptive designs are also discussed.

  6. Adaptive network countermeasures.

    SciTech Connect

    McClelland-Bane, Randy; Van Randwyk, Jamie A.; Carathimas, Anthony G.; Thomas, Eric D.

    2003-10-01

    This report describes the results of a two-year LDRD funded by the Differentiating Technologies investment area. The project investigated the use of countermeasures in protecting computer networks as well as how current countermeasures could be changed in order to adapt with both evolving networks and evolving attackers. The work involved collaboration between Sandia employees and students in the Sandia - California Center for Cyber Defenders (CCD) program. We include an explanation of the need for adaptive countermeasures, a description of the architecture we designed to provide adaptive countermeasures, and evaluations of the system.

  7. Adaptive algebraic reconstruction technique

    SciTech Connect

    Lu Wenkai; Yin Fangfang

    2004-12-01

    Algebraic reconstruction techniques (ART) are iterative procedures for reconstructing objects from their projections. It is proven that ART can be computationally efficient by carefully arranging the order in which the collected data are accessed during the reconstruction procedure and adaptively adjusting the relaxation parameters. In this paper, an adaptive algebraic reconstruction technique (AART), which adopts the same projection access scheme in multilevel scheme algebraic reconstruction technique (MLS-ART), is proposed. By introducing adaptive adjustment of the relaxation parameters during the reconstruction procedure, one-iteration AART can produce reconstructions with better quality, in comparison with one-iteration MLS-ART. Furthermore, AART outperforms MLS-ART with improved computational efficiency.

  8. [Adaptive optics for ophthalmology].

    PubMed

    Saleh, M

    2016-04-01

    Adaptive optics is a technology enhancing the visual performance of an optical system by correcting its optical aberrations. Adaptive optics have already enabled several breakthroughs in the field of visual sciences, such as improvement of visual acuity in normal and diseased eyes beyond physiologic limits, and the correction of presbyopia. Adaptive optics technology also provides high-resolution, in vivo imaging of the retina that may eventually help to detect the onset of retinal conditions at an early stage and provide better assessment of treatment efficacy. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Adaptive optics ophthalmoscopy.

    PubMed

    Roorda, A

    2000-01-01

    Retinal images in the human eye are normally degraded because we are forced to use the optical system of the human eye--which is fraught with aberrations--as the objective lens. The recent application of adaptive optics technology to measure and compensate for these aberrations has produced retinal images in human eyes with unprecedented resolution. The adaptive optics ophthalmoscope is used to take pictures of photoreceptors and capillaries and to study spectral and angular tuning properties of individual photoreceptors. Application of adaptive optics technology for ophthalmoscopy promises continued progress toward understanding the basic properties of the living human retina and also for clinical applications.

  10. Adaptive Neuromorphic Architecture (ANA).

    PubMed

    Wang, Frank Zhigang; Chua, Leon O; Yang, Xiao; Helian, Na; Tetzlaff, Ronald; Schmidt, Torsten; Li, Caroline; Carrasco, Jose Manuel Garcia; Chen, Wanlong; Chu, Dominique

    2013-09-01

    We designed Adaptive Neuromorphic Architecture (ANA) that self-adjusts its inherent parameters (for instance, the resonant frequency) naturally following the stimuli frequency. Such an architecture is required for brain-like engineered systems because some parameters of the stimuli (for instance, the stimuli frequency) are not known in advance. Such adaptivity comes from a circuit element with memory, namely mem-inductor or mem-capacitor (memristor's sisters), which is history-dependent in its behavior. As a hardware model of biological systems, ANA can be used to adaptively reproduce the observed biological phenomena in amoebae. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Adaptive Telemetry Multiplexer

    NASA Technical Reports Server (NTRS)

    Sinderson, R. L.; Salazar, G. A.; Haddick, C. M., Jr.; Spahn, C. J.; Venkatesh, C. N.

    1989-01-01

    Telemetry-data-acquisition unit adjusted remotely to produce changes in sampling rate, sampling channels, measurement scale, and output-bias level. Functional configuration adapted to changing conditions or new requirements by distant operator over telemetry link. Reconfiguration done in real time, without removing equipment from service. Bus-interface unit accepts reprogramming commands and translates them for low-rate adaptive multiplexer. Reprogrammable equipment reduces need for spare parts, since not necessary to stock variety of hardware with fixed characteristics. Adaptive multiplexer performs well in tests, amplitude errors less than 0.5 percent, distortion less than 0.25 percent, and crosstalk and common-mode rejection indiscernible.

  12. Rocketing into Adaptive Inquiry.

    ERIC Educational Resources Information Center

    Farenga, Stephen J.; Joyce, Beverly A.; Dowling, Thomas W.

    2002-01-01

    Defines adaptive inquiry and argues for employing this method which allows lessons to be shaped in response to student needs. Illustrates this idea by detailing an activity in which teams of students build rockets. (DDR)

  13. Adaptive Heat Engine.

    PubMed

    Allahverdyan, A E; Babajanyan, S G; Martirosyan, N H; Melkikh, A V

    2016-07-15

    A major limitation of many heat engines is that their functioning demands on-line control and/or an external fitting between the environmental parameters (e.g., temperatures of thermal baths) and internal parameters of the engine. We study a model for an adaptive heat engine, where-due to feedback from the functional part-the engine's structure adapts to given thermal baths. Hence, no on-line control and no external fitting are needed. The engine can employ unknown resources; it can also adapt to results of its own functioning that make the bath temperatures closer. We determine resources of adaptation and relate them to the prior information available about the environment.

  14. Adaptive Management of Ecosystems

    EPA Science Inventory

    Adaptive management is an approach to natural resource management that emphasizes learning through management. As such, management may be treated as experiment, with replication, or management may be conducted in an iterative manner. Although the concept has resonated with many...

  15. The genomics of adaptation.

    PubMed

    Radwan, Jacek; Babik, Wiesław

    2012-12-22

    The amount and nature of genetic variation available to natural selection affect the rate, course and outcome of evolution. Consequently, the study of the genetic basis of adaptive evolutionary change has occupied biologists for decades, but progress has been hampered by the lack of resolution and the absence of a genome-level perspective. Technological advances in recent years should now allow us to answer many long-standing questions about the nature of adaptation. The data gathered so far are beginning to challenge some widespread views of the way in which natural selection operates at the genomic level. Papers in this Special Feature of Proceedings of the Royal Society B illustrate various aspects of the broad field of adaptation genomics. This introductory article sets up a context and, on the basis of a few selected examples, discusses how genomic data can advance our understanding of the process of adaptation.

  16. Rocketing into Adaptive Inquiry.

    ERIC Educational Resources Information Center

    Farenga, Stephen J.; Joyce, Beverly A.; Dowling, Thomas W.

    2002-01-01

    Defines adaptive inquiry and argues for employing this method which allows lessons to be shaped in response to student needs. Illustrates this idea by detailing an activity in which teams of students build rockets. (DDR)

  17. Telescope Adaptive Optics Code

    SciTech Connect

    Phillion, D.

    2005-07-28

    The Telescope AO Code has general adaptive optics capabilities plus specialized models for three telescopes with either adaptive optics or active optics systems. It has the capability to generate either single-layer or distributed Kolmogorov turbulence phase screens using the FFT. Missing low order spatial frequencies are added using the Karhunen-Loeve expansion. The phase structure curve is extremely dose to the theoreUcal. Secondly, it has the capability to simulate an adaptive optics control systems. The default parameters are those of the Keck II adaptive optics system. Thirdly, it has a general wave optics capability to model the science camera halo due to scintillation from atmospheric turbulence and the telescope optics. Although this capability was implemented for the Gemini telescopes, the only default parameter specific to the Gemini telescopes is the primary mirror diameter. Finally, it has a model for the LSST active optics alignment strategy. This last model is highly specific to the LSST

  18. Adaptive Management of Ecosystems

    EPA Science Inventory

    Adaptive management is an approach to natural resource management that emphasizes learning through management. As such, management may be treated as experiment, with replication, or management may be conducted in an iterative manner. Although the concept has resonated with many...

  19. Leak test adapter for containers

    DOEpatents

    Hallett, Brian H.; Hartley, Michael S.

    1996-01-01

    An adapter is provided for facilitating the charging of containers and leak testing penetration areas. The adapter comprises an adapter body and stem which are secured to the container's penetration areas. The container is then pressurized with a tracer gas. Manipulating the adapter stem installs a penetration plug allowing the adapter to be removed and the penetration to be leak tested with a mass spectrometer. Additionally, a method is provided for using the adapter.

  20. Adaptive Motivation Theory.

    DTIC Science & Technology

    1982-02-01

    decades in an attempt to guide theory and research in animal and human learning . More recently, the orthodox behaviorists have added the category of...suggestion which will prove important in the discussion of Adaptive Motivation Theory below: he suggests that two subdivisions of learning involve learning ...of Adaptive Motivation Theory Figure 1 presents a hierarchy of learning sequences. This Insert Figure I about here hierarchy suggests that individuals

  1. Adaptable DC offset correction

    NASA Technical Reports Server (NTRS)

    Golusky, John M. (Inventor); Muldoon, Kelly P. (Inventor)

    2009-01-01

    Methods and systems for adaptable DC offset correction are provided. An exemplary adaptable DC offset correction system evaluates an incoming baseband signal to determine an appropriate DC offset removal scheme; removes a DC offset from the incoming baseband signal based on the appropriate DC offset scheme in response to the evaluated incoming baseband signal; and outputs a reduced DC baseband signal in response to the DC offset removed from the incoming baseband signal.

  2. Adaptive Gaussian Pattern Classification

    DTIC Science & Technology

    1988-08-01

    redundant model of the data to be used in classification . There are two classes of learning, or adaptation schemes. The first, unsupervised learning...37, No. 3, pp. 242-247, 1983. [2] E. F. Codd, Cellular Automata , Academic Press, 1968. [31 H. Everett, G. Gilbreath, S. Alderson, D. J. Marchette...Na al Oca aytm aete !JTI FL E COPY AD-A 199 030 Technical Document 1335 August 1988 Adaptive Gaussian Pattern Classif ication C. E. Priebe D. J

  3. Robust Adaptive Control

    NASA Technical Reports Server (NTRS)

    Narendra, K. S.; Annaswamy, A. M.

    1985-01-01

    Several concepts and results in robust adaptive control are are discussed and is organized in three parts. The first part surveys existing algorithms. Different formulations of the problem and theoretical solutions that have been suggested are reviewed here. The second part contains new results related to the role of persistent excitation in robust adaptive systems and the use of hybrid control to improve robustness. In the third part promising new areas for future research are suggested which combine different approaches currently known.

  4. Driver Adaptive Warning Systems

    DTIC Science & Technology

    1998-03-01

    this threshold, an alarm is triggered. Since TLC based systems can have user defined thresholds, a warning can be given as early as desired. However, the...Driver Adaptive Warning Systems Thesis Proposal Parag H. Batavia CMU-RI-TR-98-07 The Robotics Institute Carnegie Mellon University Pittsburgh...control number. 1. REPORT DATE MAR 1998 2. REPORT TYPE 3. DATES COVERED 00-00-1998 to 00-00-1998 4. TITLE AND SUBTITLE Driver Adaptive Warning

  5. Orion Crew Module Adapter

    NASA Image and Video Library

    2015-11-12

    Offloading of the Orion Crew Module Adapter, CMA, at Plum Brook Station. The adapter will connect Orion’s crew module to a service module provided by ESA (European Space Agency). NASA is preparing for a series of tests that will check out the Orion European Service Module, a critical part of the spacecraft that will be launched on future missions to an asteroid and on toward Mars.

  6. Adaptation and perceptual norms

    NASA Astrophysics Data System (ADS)

    Webster, Michael A.; Yasuda, Maiko; Haber, Sara; Leonard, Deanne; Ballardini, Nicole

    2007-02-01

    We used adaptation to examine the relationship between perceptual norms--the stimuli observers describe as psychologically neutral, and response norms--the stimulus levels that leave visual sensitivity in a neutral or balanced state. Adapting to stimuli on opposite sides of a neutral point (e.g. redder or greener than white) biases appearance in opposite ways. Thus the adapting stimulus can be titrated to find the unique adapting level that does not bias appearance. We compared these response norms to subjectively defined neutral points both within the same observer (at different retinal eccentricities) and between observers. These comparisons were made for visual judgments of color, image focus, and human faces, stimuli that are very different and may depend on very different levels of processing, yet which share the property that for each there is a well defined and perceptually salient norm. In each case the adaptation aftereffects were consistent with an underlying sensitivity basis for the perceptual norm. Specifically, response norms were similar to and thus covaried with the perceptual norm, and under common adaptation differences between subjectively defined norms were reduced. These results are consistent with models of norm-based codes and suggest that these codes underlie an important link between visual coding and visual experience.

  7. Adaptive Monte Carlo methods

    NASA Astrophysics Data System (ADS)

    Fasnacht, Marc

    We develop adaptive Monte Carlo methods for the calculation of the free energy as a function of a parameter of interest. The methods presented are particularly well-suited for systems with complex energy landscapes, where standard sampling techniques have difficulties. The Adaptive Histogram Method uses a biasing potential derived from histograms recorded during the simulation to achieve uniform sampling in the parameter of interest. The Adaptive Integration method directly calculates an estimate of the free energy from the average derivative of the Hamiltonian with respect to the parameter of interest and uses it as a biasing potential. We compare both methods to a state of the art method, and demonstrate that they compare favorably for the calculation of potentials of mean force of dense Lennard-Jones fluids. We use the Adaptive Integration Method to calculate accurate potentials of mean force for different types of simple particles in a Lennard-Jones fluid. Our approach allows us to separate the contributions of the solvent to the potential of mean force from the effect of the direct interaction between the particles. With contributions of the solvent determined, we can find the potential of mean force directly for any other direct interaction without additional simulations. We also test the accuracy of the Adaptive Integration Method on a thermodynamic cycle, which allows us to perform a consistency check between potentials of mean force and chemical potentials calculated using the Adaptive Integration Method. The results demonstrate a high degree of consistency of the method.

  8. Intestinal adaptation following resection.

    PubMed

    Tappenden, Kelly A

    2014-05-01

    Intestinal adaptation is a natural compensatory process that occurs following extensive intestinal resection, whereby structural and functional changes in the intestine improve nutrient and fluid absorption in the remnant bowel. In animal studies, postresection structural adaptations include bowel lengthening and thickening and increases in villus height and crypt depth. Functional changes include increased nutrient transporter expression, accelerated crypt cell differentiation, and slowed transit time. In adult humans, data regarding adaptive changes are sparse, and the mechanisms underlying intestinal adaptation remain to be fully elucidated. Several factors influence the degree of intestinal adaptation that occurs post resection, including site and extent of resection, luminal stimulation with enteral nutrients, and intestinotrophic factors. Two intestinotrophic growth factors, the glucagon-like peptide 2 analog teduglutide and recombinant growth hormone (somatropin), are now approved for clinical use in patients with short bowel syndrome (SBS). Both agents enhance fluid absorption and decrease requirements for parenteral nutrition (PN) and/or intravenous fluid. Intestinal adaptation has been thought to be limited to the first 1-2 years following resection in humans. However, recent data suggest that a significant proportion of adult patients with SBS can achieve enteral autonomy, even after many years of PN dependence, particularly with trophic stimulation.

  9. Adaptation through proportion

    NASA Astrophysics Data System (ADS)

    Xiong, Liyang; Shi, Wenjia; Tang, Chao

    2016-08-01

    Adaptation is a ubiquitous feature in biological sensory and signaling networks. It has been suggested that adaptive systems may follow certain simple design principles across diverse organisms, cells and pathways. One class of networks that can achieve adaptation utilizes an incoherent feedforward control, in which two parallel signaling branches exert opposite but proportional effects on the output at steady state. In this paper, we generalize this adaptation mechanism by establishing a steady-state proportionality relationship among a subset of nodes in a network. Adaptation can be achieved by using any two nodes in the sub-network to respectively regulate the output node positively and negatively. We focus on enzyme networks and first identify basic regulation motifs consisting of two and three nodes that can be used to build small networks with proportional relationships. Larger proportional networks can then be constructed modularly similar to LEGOs. Our method provides a general framework to construct and analyze a class of proportional and/or adaptation networks with arbitrary size, flexibility and versatile functional features.

  10. The Climate Adaptation Frontier

    SciTech Connect

    Preston, Benjamin L

    2013-01-01

    Climate adaptation has emerged as a mainstream risk management strategy for assisting in maintaining socio-ecological systems within the boundaries of a safe operating space. Yet, there are limits to the ability of systems to adapt. Here, we introduce the concept of an adaptation frontier , which is defined as a socio-ecological system s transitional adaptive operating space between safe and unsafe domains. A number of driving forces are responsible for determining the sustainability of systems on the frontier. These include path dependence, adaptation/development deficits, values conflicts and discounting of future loss and damage. The cumulative implications of these driving forces are highly uncertain. Nevertheless, the fact that a broad range of systems already persist at the edge of their frontiers suggests a high likelihood that some limits will eventually be exceeded. The resulting system transformation is likely to manifest as anticipatory modification of management objectives or loss and damage. These outcomes vary significantly with respect to their ethical implications. Successful navigation of the adaptation frontier will necessitate new paradigms of risk governance to elicit knowledge that encourages reflexive reevaluation of societal values that enable or constrain sustainability.

  11. Adaptation with transcriptional regulation

    NASA Astrophysics Data System (ADS)

    Shi, Wenjia; Ma, Wenzhe; Xiong, Liyang; Zhang, Mingyue; Tang, Chao

    2017-02-01

    Biochemical adaptation is one of the basic functions that are widely implemented in biological systems for a variety of purposes such as signal sensing, stress response and homeostasis. The adaptation time scales span from milliseconds to days, involving different regulatory machineries in different processes. The adaptive networks with enzymatic regulation (ERNs) have been investigated in detail. But it remains unclear if and how other forms of regulation will impact the network topology and other features of the function. Here, we systematically studied three-node transcriptional regulatory networks (TRNs), with three different types of gene regulation logics. We found that the topologies of adaptive gene regulatory networks can still be grouped into two general classes: negative feedback loop (NFBL) and incoherent feed-forward loop (IFFL), but with some distinct topological features comparing to the enzymatic networks. Specifically, an auto-activation loop on the buffer node is necessary for the NFBL class. For IFFL class, the control node can be either a proportional node or an inversely-proportional node. Furthermore, the tunability of adaptive behavior differs between TRNs and ERNs. Our findings highlight the role of regulation forms in network topology, implementation and dynamics.

  12. Adaptation with transcriptional regulation

    PubMed Central

    Shi, Wenjia; Ma, Wenzhe; Xiong, Liyang; Zhang, Mingyue; Tang, Chao

    2017-01-01

    Biochemical adaptation is one of the basic functions that are widely implemented in biological systems for a variety of purposes such as signal sensing, stress response and homeostasis. The adaptation time scales span from milliseconds to days, involving different regulatory machineries in different processes. The adaptive networks with enzymatic regulation (ERNs) have been investigated in detail. But it remains unclear if and how other forms of regulation will impact the network topology and other features of the function. Here, we systematically studied three-node transcriptional regulatory networks (TRNs), with three different types of gene regulation logics. We found that the topologies of adaptive gene regulatory networks can still be grouped into two general classes: negative feedback loop (NFBL) and incoherent feed-forward loop (IFFL), but with some distinct topological features comparing to the enzymatic networks. Specifically, an auto-activation loop on the buffer node is necessary for the NFBL class. For IFFL class, the control node can be either a proportional node or an inversely-proportional node. Furthermore, the tunability of adaptive behavior differs between TRNs and ERNs. Our findings highlight the role of regulation forms in network topology, implementation and dynamics. PMID:28233824

  13. Convergence, adaptation, and constraint.

    PubMed

    Losos, Jonathan B

    2011-07-01

    Convergent evolution of similar phenotypic features in similar environmental contexts has long been taken as evidence of adaptation. Nonetheless, recent conceptual and empirical developments in many fields have led to a proliferation of ideas about the relationship between convergence and adaptation. Despite criticism from some systematically minded biologists, I reaffirm that convergence in taxa occupying similar selective environments often is the result of natural selection. However, convergent evolution of a trait in a particular environment can occur for reasons other than selection on that trait in that environment, and species can respond to similar selective pressures by evolving nonconvergent adaptations. For these reasons, studies of convergence should be coupled with other methods-such as direct measurements of selection or investigations of the functional correlates of trait evolution-to test hypotheses of adaptation. The independent acquisition of similar phenotypes by the same genetic or developmental pathway has been suggested as evidence of constraints on adaptation, a view widely repeated as genomic studies have documented phenotypic convergence resulting from change in the same genes, sometimes even by the same mutation. Contrary to some claims, convergence by changes in the same genes is not necessarily evidence of constraint, but rather suggests hypotheses that can test the relative roles of constraint and selection in directing phenotypic evolution. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  14. Solar tomography adaptive optics.

    PubMed

    Ren, Deqing; Zhu, Yongtian; Zhang, Xi; Dou, Jiangpei; Zhao, Gang

    2014-03-10

    Conventional solar adaptive optics uses one deformable mirror (DM) and one guide star for wave-front sensing, which seriously limits high-resolution imaging over a large field of view (FOV). Recent progress toward multiconjugate adaptive optics indicates that atmosphere turbulence induced wave-front distortion at different altitudes can be reconstructed by using multiple guide stars. To maximize the performance over a large FOV, we propose a solar tomography adaptive optics (TAO) system that uses tomographic wave-front information and uses one DM. We show that by fully taking advantage of the knowledge of three-dimensional wave-front distribution, a classical solar adaptive optics with one DM can provide an extra performance gain for high-resolution imaging over a large FOV in the near infrared. The TAO will allow existing one-deformable-mirror solar adaptive optics to deliver better performance over a large FOV for high-resolution magnetic field investigation, where solar activities occur in a two-dimensional field up to 60'', and where the near infrared is superior to the visible in terms of magnetic field sensitivity.

  15. Adaptive spectral doppler estimation.

    PubMed

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-04-01

    In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence. The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to provide good spectral resolution and contrast even when the observation window is very short. The 2 adaptive techniques are tested and compared with the averaged periodogram (Welch's method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set of matched filters (one for each velocity component of interest) and filtering the blood process over slow-time and averaging over depth to find the PSD. The methods are tested using various experiments and simulations. First, controlled flow-rig experiments with steady laminar flow are carried out. Simulations in Field II for pulsating flow resembling the femoral artery are also analyzed. The simulations are followed by in vivo measurement on the common carotid artery. In all simulations and experiments it was concluded that the adaptive methods display superior performance for short observation windows compared with the averaged periodogram. Computational costs and implementation details are also discussed.

  16. Adaptation with transcriptional regulation.

    PubMed

    Shi, Wenjia; Ma, Wenzhe; Xiong, Liyang; Zhang, Mingyue; Tang, Chao

    2017-02-24

    Biochemical adaptation is one of the basic functions that are widely implemented in biological systems for a variety of purposes such as signal sensing, stress response and homeostasis. The adaptation time scales span from milliseconds to days, involving different regulatory machineries in different processes. The adaptive networks with enzymatic regulation (ERNs) have been investigated in detail. But it remains unclear if and how other forms of regulation will impact the network topology and other features of the function. Here, we systematically studied three-node transcriptional regulatory networks (TRNs), with three different types of gene regulation logics. We found that the topologies of adaptive gene regulatory networks can still be grouped into two general classes: negative feedback loop (NFBL) and incoherent feed-forward loop (IFFL), but with some distinct topological features comparing to the enzymatic networks. Specifically, an auto-activation loop on the buffer node is necessary for the NFBL class. For IFFL class, the control node can be either a proportional node or an inversely-proportional node. Furthermore, the tunability of adaptive behavior differs between TRNs and ERNs. Our findings highlight the role of regulation forms in network topology, implementation and dynamics.

  17. Adaptation and risk management

    SciTech Connect

    Preston, Benjamin L

    2011-01-01

    Adaptation assessment methods are compatible with the international risk management standard ISO:31000. Risk management approaches are increasingly being recommended for adaptation assessments at both national and local levels. Two orientations to assessments can commonly be identified: top-down and bottom-up, and prescriptive and diagnostic. Combinations of these orientations favor different types of assessments. The choice of orientation can be related to uncertainties in prediction and taking action, in the type of adaptation and in the degree of system stress. Adopting multiple viewpoints is to be encouraged, especially in complex situations. The bulk of current guidance material is consistent with top-down and predictive approaches, thus is most suitable for risk scoping and identification. Abroad range ofmaterial fromwithin and beyond the climate change literature can be used to select methods to be used in assessing and implementing adaptation. The framing of risk, correct formulation of the questions being investigated and assessment methodology are critical aspects of the scoping phase. Only when these issues have been addressed should be issue of specific methods and tools be addressed. The reorientation of adaptation from an assessment focused solely on anthropogenic climate change to broader issues of vulnerability/resilience, sustainable development and disaster risk, especially through a risk management framework, can draw from existing policy and management understanding in communities, professions and agencies, incorporating existing agendas, knowledge, risks, and issues they already face.

  18. Solar Adaptive Optics.

    PubMed

    Rimmele, Thomas R; Marino, Jose

    Adaptive optics (AO) has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO) and Ground-Layer AO (GLAO) will be given.

  19. Advances in Adaptive Control Methods

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan

    2009-01-01

    This poster presentation describes recent advances in adaptive control technology developed by NASA. Optimal Control Modification is a novel adaptive law that can improve performance and robustness of adaptive control systems. A new technique has been developed to provide an analytical method for computing time delay stability margin for adaptive control systems.

  20. Adaptive tracking system

    NASA Astrophysics Data System (ADS)

    Kulpa, Krzysztof; Centkowski, Grzymislaw; Wojtkiewicz, Andrzej; Klembowski, Wieslaw

    The paper presents an efficient adaptive tracking system for surveillance ATC radar. The system was implemented in software on an INTEL-80286-based machine. The tracking filter was built as a cascade of the Kalman filters and maneuver correction FIR filter. It ensures fast adaptation to maneuvers, low prediction error, and low computational complexity. The maneuver detector, combined with a measurement error variance estimator, controls the filter gains according to the detected maneuver and selects the proper size of a plot-track correlation gate. The system features high accuracy and throughput. It can adapt to changes of false plot density, detection probability, and variance of measurement error, as well as to pilot-induced maneuvers.

  1. Cardiovascular adaptation to spaceflight

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.; Watenpaugh, D. E.

    1996-01-01

    This article reviews recent flight and ground-based studies of cardiovascular adaptation to spaceflight. Prominent features of microgravity exposure include loss of gravitational pressures, relatively low venous pressures, headward fluid shifts, plasma volume loss, and postflight orthostatic intolerance and reduced exercise capacity. Many of these short-term responses to microgravity extend themselves during long-duration microgravity exposure and may be explained by altered pressures (blood and tissue) and fluid balance in local tissues nourished by the cardiovascular system. In this regard, it is particularly noteworthy that tissues of the lower body (e.g., foot) are well adapted to local hypertension on Earth, whereas tissues of the upper body (e.g., head) are not as well adapted to increase in local blood pressure. For these and other reasons, countermeasures for long-duration flight should include reestablishment of higher, Earth-like blood pressures in the lower body.

  2. Adaptive modulations of martensites.

    PubMed

    Kaufmann, S; Rössler, U K; Heczko, O; Wuttig, M; Buschbeck, J; Schultz, L; Fähler, S

    2010-04-09

    Modulated phases occur in numerous functional materials like giant ferroelectrics and magnetic shape-memory alloys. To understand the origin of these phases, we employ and generalize the concept of adaptive martensite. As a starting point, we investigate the coexistence of austenite, adaptive 14M phase, and tetragonal martensite in Ni-Mn-Ga magnetic shape-memory alloy epitaxial films. We show that the modulated martensite can be constructed from nanotwinned variants of the tetragonal martensite phase. By combining the concept of adaptive martensite with branching of twin variants, we can explain key features of modulated phases from a microscopic view. This includes metastability, the sequence of 6M-10M-14M-NM intermartensitic transitions, and the magnetocrystalline anisotropy.

  3. Adaptive Epibiochemistry and Epigenetics.

    PubMed

    Buryanov, Ya I

    2015-09-01

    Enzymatic reactions of post-synthetic modification of macromolecules occur in the cells of all organisms. These reactions, which can be designated as epibiochemical, are of a special type and, as discriminated from reactions with low molecular weight substrates, occur on the level of biopolymers, causing their covalent modification. The majority of epibiochemical modifications of proteins, DNA, and RNA are reversible and are carried out by modification transferases and de-modification enzymes, respectively. Epibiochemical, i.e. those located above the low molecular weight metabolites, modifications of proteins and nucleic acids perform various functions, including participation in molecular mechanisms of adaptive epigenetic heredity. This paper presents an overview of some adaptive epibiochemical modifications of macromolecules and the adaptive epigenetic processes on their basis. The features of epigenetic inheritance of acquired characteristics and the limits of biological evolution are discussed.

  4. Cardiovascular adaptation to spaceflight

    NASA Technical Reports Server (NTRS)

    Charles, John B.; Lathers, Claire M.

    1991-01-01

    Data are presented on the rate of adaptation of the human cardiovascular system to conditions of spaceflight, with particular attention given to data obtained during spaceflight in the U.S. Space Shuttle Program. It is pointed out that many of the cardiovascular changes that occurred during spaceflights that lasted from 2 to 11 days can be traced directly to changes in the body fluid volume. The beneficial effects of a fluid loading countermeasure (oral rehydration) and of the supine body position on the heart rate during the spaceflight are demonstrated. It is noted that, after hours or a few days of spaceflight, a state of adaptation is reached, in which the subject is well adapted and appropriately hydrated for the weightless environment. However, the return to the normal gravity of the earth leaves the individual especially sensitive to orthostatic stress.

  5. Cardiovascular adaptation to spaceflight

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.; Watenpaugh, D. E.

    1996-01-01

    This article reviews recent flight and ground-based studies of cardiovascular adaptation to spaceflight. Prominent features of microgravity exposure include loss of gravitational pressures, relatively low venous pressures, headward fluid shifts, plasma volume loss, and postflight orthostatic intolerance and reduced exercise capacity. Many of these short-term responses to microgravity extend themselves during long-duration microgravity exposure and may be explained by altered pressures (blood and tissue) and fluid balance in local tissues nourished by the cardiovascular system. In this regard, it is particularly noteworthy that tissues of the lower body (e.g., foot) are well adapted to local hypertension on Earth, whereas tissues of the upper body (e.g., head) are not as well adapted to increase in local blood pressure. For these and other reasons, countermeasures for long-duration flight should include reestablishment of higher, Earth-like blood pressures in the lower body.

  6. Experimental adaptive process tomography

    NASA Astrophysics Data System (ADS)

    Pogorelov, I. A.; Struchalin, G. I.; Straupe, S. S.; Radchenko, I. V.; Kravtsov, K. S.; Kulik, S. P.

    2017-01-01

    Adaptive measurements were recently shown to significantly improve the performance of quantum state tomography. Utilizing information about the system for the online choice of optimal measurements allows one to reach the ultimate bounds of precision for state reconstruction. In this article we generalize an adaptive Bayesian approach to the case of process tomography and experimentally show its superiority in the task of learning unknown quantum operations. Our experiments with photonic polarization qubits cover all types of single-qubit channels. We also discuss instrumental errors and the criteria for evaluation of the ultimate achievable precision in an experiment. It turns out that adaptive tomography provides a lower noise floor in the presence of strong technical noise.

  7. Adaptive core simulation

    NASA Astrophysics Data System (ADS)

    Abdel-Khalik, Hany Samy

    The work presented in this thesis is a continuation of a master's thesis research project conducted by the author to gain insight into the applicability of inverse methods to developing adaptive simulation capabilities for core physics problems. Use of adaptive simulation is intended to improve the fidelity and robustness of important core attributes predictions such as core power distribution, thermal margins and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e. in-core instrumentations readings, to adapt the simulation in a meaningful way. A meaningful adaption will result in high fidelity and robust adapted core simulators models. To perform adaption, we propose an inverse theory approach in which the multitudes of input data to core simulators, i.e. reactor physics and thermal-hydraulic data, are to be adjusted to improve agreement with measured observables while keeping core simulators models unadapted. At a first glance, devising such adaption for typical core simulators models would render the approach impractical. This follows, since core simulators are based on very demanding computational models, i.e. based on complex physics models with millions of input data and output observables. This would spawn not only several prohibitive challenges but also numerous disparaging concerns. The challenges include the computational burdens of the sensitivity-type calculations required to construct Jacobian operators for the core simulators models. Also, the computational burdens of the uncertainty-type calculations required to estimate the uncertainty information of core simulators input data presents a demanding challenge. The concerns however are mainly related to the reliability of the adjusted input data. We demonstrate that the power of our proposed approach is mainly driven by taking advantage of this unfavorable situation. Our contribution begins with the realization that to obtain

  8. Adaptive response modelling

    NASA Astrophysics Data System (ADS)

    Campa, Alessandro; Esposito, Giuseppe; Belli, Mauro

    Cellular response to radiation is often modified by a previous delivery of a small "priming" dose: a smaller amount of damage, defined by the end point being investigated, is observed, and for this reason the effect is called adaptive response. An improved understanding of this effect is essential (as much as for the case of the bystander effect) for a reliable radiation risk assessment when low dose irradiations are involved. Experiments on adaptive response have shown that there are a number of factors that strongly influence the occurrence (and the level) of the adaptation. In particular, priming doses and dose rates have to fall in defined ranges; the same is true for the time interval between the delivery of the small priming dose and the irradiation with the main, larger, dose (called in this case challenging dose). Different hypotheses can be formulated on the main mechanism(s) determining the adaptive response: an increased efficiency of DNA repair, an increased level of antioxidant enzymes, an alteration of cell cycle progression, a chromatin conformation change. An experimental clearcut evidence going definitely in the direction of one of these explanations is not yet available. Modelling can be done at different levels. Simple models, relating the amount of damage, through elementary differential equations, to the dose and dose rate experienced by the cell, are relatively easy to handle, and they can be modified to account for the priming irradiation. However, this can hardly be of decisive help in the explanation of the mechanisms, since each parameter of these models often incorporates in an effective way several cellular processes related to the response to radiation. In this presentation we show our attempts to describe adaptive response with models that explicitly contain, as a dynamical variable, the inducible adaptive agent. At a price of a more difficult treatment, this approach is probably more prone to give support to the experimental studies

  9. Adaptive cockroach swarm algorithm

    NASA Astrophysics Data System (ADS)

    Obagbuwa, Ibidun C.; Abidoye, Ademola P.

    2017-07-01

    An adaptive cockroach swarm optimization (ACSO) algorithm is proposed in this paper to strengthen the existing cockroach swarm optimization (CSO) algorithm. The ruthless component of CSO algorithm is modified by the employment of blend crossover predator-prey evolution method which helps algorithm prevent any possible population collapse, maintain population diversity and create adaptive search in each iteration. The performance of the proposed algorithm on 16 global optimization benchmark function problems was evaluated and compared with the existing CSO, cuckoo search, differential evolution, particle swarm optimization and artificial bee colony algorithms.

  10. Adaptive piezoelectric sensoriactuator

    NASA Technical Reports Server (NTRS)

    Clark, Jr., Robert L. (Inventor); Vipperman, Jeffrey S. (Inventor); Cole, Daniel G. (Inventor)

    1996-01-01

    An adaptive algorithm implemented in digital or analog form is used in conjunction with a voltage controlled amplifier to compensate for the feedthrough capacitance of piezoelectric sensoriactuator. The mechanical response of the piezoelectric sensoriactuator is resolved from the electrical response by adaptively altering the gain imposed on the electrical circuit used for compensation. For wideband, stochastic input disturbances, the feedthrough capacitance of the sensoriactuator can be identified on-line, providing a means of implementing direct-rate-feedback control in analog hardware. The device is capable of on-line system health monitoring since a quasi-stable dynamic capacitance is indicative of sustained health of the piezoelectric element.

  11. Verification of Adaptive Systems

    SciTech Connect

    Pullum, Laura L; Cui, Xiaohui; Vassev, Emil; Hinchey, Mike; Rouff, Christopher; Buskens, Richard

    2012-01-01

    Adaptive systems are critical for future space and other unmanned and intelligent systems. Verification of these systems is also critical for their use in systems with potential harm to human life or with large financial investments. Due to their nondeterministic nature and extremely large state space, current methods for verification of software systems are not adequate to provide a high level of assurance for them. The combination of stabilization science, high performance computing simulations, compositional verification and traditional verification techniques, plus operational monitors, provides a complete approach to verification and deployment of adaptive systems that has not been used before. This paper gives an overview of this approach.

  12. Adaptive management: Chapter 1

    USGS Publications Warehouse

    Allen, Craig R.; Garmestani, Ahjond S.; Allen, Craig R.; Garmestani, Ahjond S.

    2015-01-01

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive management has explicit structure, including a careful elucidation of goals, identification of alternative management objectives and hypotheses of causation, and procedures for the collection of data followed by evaluation and reiteration. The process is iterative, and serves to reduce uncertainty, build knowledge and improve management over time in a goal-oriented and structured process.

  13. Adaptive Cruise Control (ACC)

    NASA Astrophysics Data System (ADS)

    Reif, Konrad

    Die adaptive Fahrgeschwindigkeitsregelung (ACC, Adaptive Cruise Control) ist eine Weiterentwicklung der konventionellen Fahrgeschwindigkeitsregelung, die eine konstante Fahrgeschwindigkeit einstellt. ACC überwacht mittels eines Radarsensors den Bereich vor dem Fahrzeug und passt die Geschwindigkeit den Gegebenheiten an. ACC reagiert auf langsamer vorausfahrende oder einscherende Fahrzeuge mit einer Reduzierung der Geschwindigkeit, sodass der vorgeschriebene Mindestabstand zum vorausfahrenden Fahrzeug nicht unterschritten wird. Hierzu greift ACC in Antrieb und Bremse ein. Sobald das vorausfahrende Fahrzeug beschleunigt oder die Spur verlässt, regelt ACC die Geschwindigkeit wieder auf die vorgegebene Sollgeschwindigkeit ein (Bild 1). ACC steht somit für eine Geschwindigkeitsregelung, die sich dem vorausfahrenden Verkehr anpasst.

  14. Robust Optimal Adaptive Control Method with Large Adaptive Gain

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan T.

    2009-01-01

    In the presence of large uncertainties, a control system needs to be able to adapt rapidly to regain performance. Fast adaptation is referred to the implementation of adaptive control with a large adaptive gain to reduce the tracking error rapidly. However, a large adaptive gain can lead to high-frequency oscillations which can adversely affect robustness of an adaptive control law. A new adaptive control modification is presented that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. The modification is based on the minimization of the Y2 norm of the tracking error, which is formulated as an optimal control problem. The optimality condition is used to derive the modification using the gradient method. The optimal control modification results in a stable adaptation and allows a large adaptive gain to be used for better tracking while providing sufficient stability robustness. Simulations were conducted for a damaged generic transport aircraft with both standard adaptive control and the adaptive optimal control modification technique. The results demonstrate the effectiveness of the proposed modification in tracking a reference model while maintaining a sufficient time delay margin.

  15. Hybrid Adaptive Flight Control with Model Inversion Adaptation

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan

    2011-01-01

    This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.

  16. Narrative, Adaptation, and Change

    ERIC Educational Resources Information Center

    Bateson, Mary Catherine

    2007-01-01

    This paper explores how individuals and communities orient themselves to the future by the way they story the past. There is a persistent tendency to think of such narratives as factual and therefore stable. The mutability of such narratives is actually a key adaptive characteristic, ranging from complete repression of individual traumas to public…

  17. Vineland Adaptive Behavior Scales.

    ERIC Educational Resources Information Center

    Icabone, Dona G.

    1999-01-01

    This article describes the Vineland Adaptive Behavior Scales, a general assessment of personal and social sufficiency of individuals from birth through adulthood to determine areas of strength and weakness. The instrument assesses communication, daily living skills, socialization, and motor skills. Its administration, standardization, reliability,…

  18. Career Adaptability in Childhood

    ERIC Educational Resources Information Center

    Hartung, Paul J.; Porfeli, Erik J.; Vondracek, Fred W.

    2008-01-01

    Childhood marks the dawn of vocational development, involving developmental tasks, transitions, and change. Children must acquire the rudiments of career adaptability to envision a future, make educational and vocational decisions, explore self and occupations, and problem solve. The authors situate child vocational development within human life…

  19. Adaptive Recreational Equipment.

    ERIC Educational Resources Information Center

    Schilling, Mary Lou, Ed.

    1983-01-01

    Designed for teachers interested in therapeutic recreation, the document lists sources of adaptive recreational equipment and their homemade counterparts. Brief descriptions for ordering or constructing recreational equipment for the visually impaired, poorly coordinated, physically impaired, and mentally retarded are given. Specific adaptations…

  20. Adaptations, Exaptations, and Spandrels.

    ERIC Educational Resources Information Center

    Buss, David M.; Haselton, Martie G.; Shackelford, Todd K.; Bleske, April L.; Wakefield, Jerome C.

    1998-01-01

    Provides a guide to the basic concepts of adaptations, exaptations, and spandrels involved in the current dispute over evolutionary explanations. Clarifies the role that each of these concepts plays in an evolutionary approach to human psychology. Contains over 100 references. (MMU)

  1. The Modular Adaptive Ribosome.

    PubMed

    Yadav, Anupama; Radhakrishnan, Aparna; Panda, Anshuman; Singh, Amartya; Sinha, Himanshu; Bhanot, Gyan

    2016-01-01

    The ribosome is an ancient machine, performing the same function across organisms. Although functionally unitary, recent experiments suggest specialized roles for some ribosomal proteins. Our central thesis is that ribosomal proteins function in a modular fashion to decode genetic information in a context dependent manner. We show through large data analyses that although many ribosomal proteins are essential with consistent effect on growth in different conditions in yeast and similar expression across cell and tissue types in mice and humans, some ribosomal proteins are used in an environment specific manner. The latter set of variable ribosomal proteins further function in a coordinated manner forming modules, which are adapted to different environmental cues in different organisms. We show that these environment specific modules of ribosomal proteins in yeast have differential genetic interactions with other pathways and their 5'UTRs show differential signatures of selection in yeast strains, presumably to facilitate adaptation. Similarly, we show that in higher metazoans such as mice and humans, different modules of ribosomal proteins are expressed in different cell types and tissues. A clear example is nervous tissue that uses a ribosomal protein module distinct from the rest of the tissues in both mice and humans. Our results suggest a novel stratification of ribosomal proteins that could have played a role in adaptation, presumably to optimize translation for adaptation to diverse ecological niches and tissue microenvironments.

  2. The Modular Adaptive Ribosome

    PubMed Central

    Yadav, Anupama; Radhakrishnan, Aparna; Panda, Anshuman; Singh, Amartya; Sinha, Himanshu; Bhanot, Gyan

    2016-01-01

    The ribosome is an ancient machine, performing the same function across organisms. Although functionally unitary, recent experiments suggest specialized roles for some ribosomal proteins. Our central thesis is that ribosomal proteins function in a modular fashion to decode genetic information in a context dependent manner. We show through large data analyses that although many ribosomal proteins are essential with consistent effect on growth in different conditions in yeast and similar expression across cell and tissue types in mice and humans, some ribosomal proteins are used in an environment specific manner. The latter set of variable ribosomal proteins further function in a coordinated manner forming modules, which are adapted to different environmental cues in different organisms. We show that these environment specific modules of ribosomal proteins in yeast have differential genetic interactions with other pathways and their 5’UTRs show differential signatures of selection in yeast strains, presumably to facilitate adaptation. Similarly, we show that in higher metazoans such as mice and humans, different modules of ribosomal proteins are expressed in different cell types and tissues. A clear example is nervous tissue that uses a ribosomal protein module distinct from the rest of the tissues in both mice and humans. Our results suggest a novel stratification of ribosomal proteins that could have played a role in adaptation, presumably to optimize translation for adaptation to diverse ecological niches and tissue microenvironments. PMID:27812193

  3. Adapting Environmental Education Materials.

    ERIC Educational Resources Information Center

    Peace Corps, Washington, DC. Information Collection and Exchange Div.

    This publication provides Peace Corps volunteers and others who conduct environmental education activities in schools, environmental education centers, parks, and communities with the tools to adapt existing environmental education resources to local environmental issues, cultures, and audiences. Sections include: (1) the process of adapting…

  4. Adaptive MGS Phase Retrieval

    NASA Technical Reports Server (NTRS)

    Basinger, Scott A.; Bikkannavar, Siddarayappa; Cohen, David; Green, Joseph J.; Lou, John; Ohara, Catherine; Redding, David; Shi, Fang

    2008-01-01

    Adaptive MGS Phase Retrieval software uses the Modified Gerchberg-Saxton (MGS) algorithm, an image-based sensing method that can turn any focal plane science instrument into a wavefront sensor, avoiding the need to use external metrology equipment. Knowledge of the wavefront enables intelligent control of active optical systems.

  5. Adaptation, Acculturation, and Ethnicity.

    ERIC Educational Resources Information Center

    Fragoso, Jose M.

    1991-01-01

    Summarizes the essential theoretical features in "Communication and Cross-Cultural Adaptation," by Young Yun Kim. Applies this theory of acculturation as a dynamic communication process to the multigenerational cross-cultural shift of Mexican-Americans described in "Chicano Identity," by Susan E. Keefe and Amado M. Padilla. (SV)

  6. Flexibility: Ensuring Adaptability.

    ERIC Educational Resources Information Center

    Van Slyke, Paul; Goode, Chris

    2003-01-01

    Discusses how to collaborate with administrators, physical plant representatives, department heads, lawmakers, and design professionals to create flexible school facilities that adapt to changing needs, noting the importance of utilizing a programming process that determines the true needs of a facility, based on the potential activities that will…

  7. Generalization of Prism Adaptation

    ERIC Educational Resources Information Center

    Redding, Gordon M.; Wallace, Benjamin

    2006-01-01

    Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial…

  8. Prism Adaptation in Schizophrenia

    ERIC Educational Resources Information Center

    Bigelow, Nirav O.; Turner, Beth M.; Andreasen, Nancy C.; Paulsen, Jane S.; O'Leary, Daniel S.; Ho, Beng-Choon

    2006-01-01

    The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also…

  9. Prism Adaptation in Schizophrenia

    ERIC Educational Resources Information Center

    Bigelow, Nirav O.; Turner, Beth M.; Andreasen, Nancy C.; Paulsen, Jane S.; O'Leary, Daniel S.; Ho, Beng-Choon

    2006-01-01

    The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also…

  10. Coupled adaptive complex networks

    NASA Astrophysics Data System (ADS)

    Shai, S.; Dobson, S.

    2013-04-01

    Adaptive networks, which combine topological evolution of the network with dynamics on the network, are ubiquitous across disciplines. Examples include technical distribution networks such as road networks and the internet, natural and biological networks, and social science networks. These networks often interact with or depend upon other networks, resulting in coupled adaptive networks. In this paper we study susceptible-infected-susceptible (SIS) epidemic dynamics on coupled adaptive networks, where susceptible nodes are able to avoid contact with infected nodes by rewiring their intranetwork connections. However, infected nodes can pass the disease through internetwork connections, which do not change with time: The dependencies between the coupled networks remain constant. We develop an analytical formalism for these systems and validate it using extensive numerical simulation. We find that stability is increased by increasing the number of internetwork links, in the sense that the range of parameters over which both endemic and healthy states coexist (both states are reachable depending on the initial conditions) becomes smaller. Finally, we find a new stable state that does not appear in the case of a single adaptive network but only in the case of weakly coupled networks, in which the infection is endemic in one network but neither becomes endemic nor dies out in the other. Instead, it persists only at the nodes that are coupled to nodes in the other network through internetwork links. We speculate on the implications of these findings.

  11. Parallel multilevel adaptive methods

    NASA Technical Reports Server (NTRS)

    Dowell, B.; Govett, M.; Mccormick, S.; Quinlan, D.

    1989-01-01

    The progress of a project for the design and analysis of a multilevel adaptive algorithm (AFAC/HM/) targeted for the Navier Stokes Computer is discussed. The results of initial timing tests of AFAC, coupled with multigrid and an efficient load balancer, on a 16-node Intel iPSC/2 hypercube are included. The results of timing tests are presented.

  12. Adapting to the Environment.

    ERIC Educational Resources Information Center

    Kovach, Amy L.

    2003-01-01

    Presents an activity on natural selection and how the peppered moth's adaptive values for their colors changed during the Industrial Revolution in Manchester, England, influencing their survival and ultimately affecting the survival of their offspring. Includes activity objectives. (Author/KHR)

  13. Generalization of Prism Adaptation

    ERIC Educational Resources Information Center

    Redding, Gordon M.; Wallace, Benjamin

    2006-01-01

    Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial…

  14. Multiple Docking Adapter Illustration

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This cutaway drawing details the major characteristics of the Skylab Multiple Docking Adapter (MDA). The MDA, built under the direction of the Marshall Space Flight Center, housed the control units for the Apollo Telescope Mount (ATM), Earth Resources Experiment Package (EREP), and Zero-Gravity Materials Processing Facility, and provided a docking port for the Apollo Command Module (CM).

  15. Adaptive sequential controller

    SciTech Connect

    El-Sharkawi, M.A.; Xing, J.; Butler, N.G.; Rodriguez, A.

    1994-11-01

    An adaptive sequential controller for controlling a circuit breaker or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer. 15 figs.

  16. Career Adaptability in Childhood

    ERIC Educational Resources Information Center

    Hartung, Paul J.; Porfeli, Erik J.; Vondracek, Fred W.

    2008-01-01

    Childhood marks the dawn of vocational development, involving developmental tasks, transitions, and change. Children must acquire the rudiments of career adaptability to envision a future, make educational and vocational decisions, explore self and occupations, and problem solve. The authors situate child vocational development within human life…

  17. Quantifying the Adaptive Cycle

    EPA Science Inventory

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative...

  18. Quantifying the Adaptive Cycle

    EPA Science Inventory

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative...

  19. Adapted Aquatics and Inclusion.

    ERIC Educational Resources Information Center

    Block, Martin E.; Conatser, Phillip

    2002-01-01

    Presents strategies and techniques to help instructors and directors promote successful inclusive aquatics programs for students with disabilities, discussing the importance of considering issues related to: teaching style, collaborative planning, goal determination, appropriate inclusive placement, personnel preparation, curriculum adaptation,…

  20. Adaptation and mitigation

    Treesearch

    Constance I. Millar; Kenneth E. Skog; Duncan C. McKinley; Richard A. Birdsey; Christopher W. Swanston; Sarah J. Hines; Christopher W. Woodall; Elizabeth D. Reinhardt; David L. Peterson; James M. Vose

    2012-01-01

    Forest ecosystems respond to natural climatic variability and human-caused climate change in ways that are adverse as well as beneficial to the biophysical environment and to society. Adaptation refers to responses or adjustments made—whether passive, reactive, or anticipatory—to climatic variability and change (Carter et al. 1994). Many adjustments occur whether...

  1. Adaptive Sampling Designs.

    ERIC Educational Resources Information Center

    Flournoy, Nancy

    Designs for sequential sampling procedures that adapt to cumulative information are discussed. A familiar illustration is the play-the-winner rule in which there are two treatments; after a random start, the same treatment is continued as long as each successive subject registers a success. When a failure occurs, the other treatment is used until…

  2. Adaptive Cruise Control

    NASA Astrophysics Data System (ADS)

    Winner, Hermann; Danner, Bernd; Steinle, Joachim

    Mit Adaptive Cruise Control, abgekürzt ACC, wird eine Fahrgeschwindigkeitsregelung bezeichnet, die sich an die Verkehrssituation anpasst. Synonyme Bezeichnungen sind Aktive Geschwindigkeitsregelung, Automatische Distanzregelung oder Abstandsregeltempomat. Im englischen Sprachraum fnden sich die weiteren Bezeichnungen Active Cruise Control, Automatic Cruise Control oder Autonomous Intelligent Cruise Control. Als markengeschützte Bezeichnungen sind Distronic und Automatische Distanz-Regelung (ADR) eingetragen.

  3. Adapting to the Environment.

    ERIC Educational Resources Information Center

    Kovach, Amy L.

    2003-01-01

    Presents an activity on natural selection and how the peppered moth's adaptive values for their colors changed during the Industrial Revolution in Manchester, England, influencing their survival and ultimately affecting the survival of their offspring. Includes activity objectives. (Author/KHR)

  4. Adaptive sequential controller

    DOEpatents

    El-Sharkawi, Mohamed A.; Xing, Jian; Butler, Nicholas G.; Rodriguez, Alonso

    1994-01-01

    An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.

  5. Transformational adaptation when incremental adaptations to climate change are insufficient.

    PubMed

    Kates, Robert W; Travis, William R; Wilbanks, Thomas J

    2012-05-08

    All human-environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations.

  6. Transformational adaptation when incremental adaptations to climate change are insufficient

    PubMed Central

    Kates, Robert W.; Travis, William R.; Wilbanks, Thomas J.

    2012-01-01

    All human–environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations. PMID:22509036

  7. Contrast Adaptation Implies Two Spatiotemporal Channels but Three Adapting Processes

    ERIC Educational Resources Information Center

    Langley, Keith; Bex, Peter J.

    2007-01-01

    The contrast gain control model of adaptation predicts that the effects of contrast adaptation correlate with contrast sensitivity. This article reports that the effects of high contrast spatiotemporal adaptors are maximum when adapting around 19 Hz, which is a factor of two or more greater than the peak in contrast sensitivity. To explain the…

  8. Adaptive Algebraic Multigrid Methods

    SciTech Connect

    Brezina, M; Falgout, R; MacLachlan, S; Manteuffel, T; McCormick, S; Ruge, J

    2004-04-09

    Our ability to simulate physical processes numerically is constrained by our ability to solve the resulting linear systems, prompting substantial research into the development of multiscale iterative methods capable of solving these linear systems with an optimal amount of effort. Overcoming the limitations of geometric multigrid methods to simple geometries and differential equations, algebraic multigrid methods construct the multigrid hierarchy based only on the given matrix. While this allows for efficient black-box solution of the linear systems associated with discretizations of many elliptic differential equations, it also results in a lack of robustness due to assumptions made on the near-null spaces of these matrices. This paper introduces an extension to algebraic multigrid methods that removes the need to make such assumptions by utilizing an adaptive process. The principles which guide the adaptivity are highlighted, as well as their application to algebraic multigrid solution of certain symmetric positive-definite linear systems.

  9. Adaptive manifold learning.

    PubMed

    Zhang, Zhenyue; Wang, Jing; Zha, Hongyuan

    2012-02-01

    Manifold learning algorithms seek to find a low-dimensional parameterization of high-dimensional data. They heavily rely on the notion of what can be considered as local, how accurately the manifold can be approximated locally, and, last but not least, how the local structures can be patched together to produce the global parameterization. In this paper, we develop algorithms that address two key issues in manifold learning: 1) the adaptive selection of the local neighborhood sizes when imposing a connectivity structure on the given set of high-dimensional data points and 2) the adaptive bias reduction in the local low-dimensional embedding by accounting for the variations in the curvature of the manifold as well as its interplay with the sampling density of the data set. We demonstrate the effectiveness of our methods for improving the performance of manifold learning algorithms using both synthetic and real-world data sets.

  10. Bacterial surface adaptation

    NASA Astrophysics Data System (ADS)

    Utada, Andrew

    2014-03-01

    Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

  11. Retroelements: propagation and adaptation.

    PubMed

    Hull, R; Covey, S N

    1995-01-01

    Retroelements are genetic entities that exist in both DNA and RNA forms generated by cyclic alternation of transcription and reverse transcription. They have in common a genetic core (the gag-pol core), encoding conserved functions of a structural protein and a replicase. These are supplemented with a variety of cis-acting nucleic acid sequences controlling transcription and reverse transcription. Most retroelements have additional genes with regulatory or adaptive roles, both within the cell and for movement between cells and organisms. These features reflect the variety of mechanisms that have developed to ensure propagation of the elements and their ability to adapt to specific niches in their hosts with which they co-evolve.

  12. Adaptive passive fathometer processing.

    PubMed

    Siderius, Martin; Song, Heechun; Gerstoft, Peter; Hodgkiss, William S; Hursky, Paul; Harrison, Chris

    2010-04-01

    Recently, a technique has been developed to image seabed layers using the ocean ambient noise field as the sound source. This so called passive fathometer technique exploits the naturally occurring acoustic sounds generated on the sea-surface, primarily from breaking waves. The method is based on the cross-correlation of noise from the ocean surface with its echo from the seabed, which recovers travel times to significant seabed reflectors. To limit averaging time and make this practical, beamforming is used with a vertical array of hydrophones to reduce interference from horizontally propagating noise. The initial development used conventional beamforming, but significant improvements have been realized using adaptive techniques. In this paper, adaptive methods for this process are described and applied to several data sets to demonstrate improvements possible as compared to conventional processing.

  13. Automatic transmission adapter kit

    SciTech Connect

    Stich, R.L.; Neal, W.D.

    1987-02-10

    This patent describes, in a four-wheel-drive vehicle apparatus having a power train including an automatic transmission and a transfer case, an automatic transmission adapter kit for installation of a replacement automatic transmission of shorter length than an original automatic transmission in the four-wheel-drive vehicle. The adapter kit comprises: an extension housing interposed between the replacement automatic transmission and the transfer case; an output shaft, having a first end which engages the replacement automatic transmission and a second end which engages the transfer case; first sealing means for sealing between the extension housing and the replacement automatic transmission; second sealing means for sealing between the extension housing and the transfer case; and fastening means for connecting the extension housing between the replacement automatic transmission and the transfer case.

  14. NEEDS - Information Adaptive System

    NASA Technical Reports Server (NTRS)

    Kelly, W. L.; Benz, H. F.; Meredith, B. D.

    1980-01-01

    The Information Adaptive System (IAS) is an element of the NASA End-to-End Data System (NEEDS) Phase II and is focused toward onboard image processing. The IAS is a data preprocessing system which is closely coupled to the sensor system. Some of the functions planned for the IAS include sensor response nonuniformity correction, geometric correction, data set selection, data formatting, packetization, and adaptive system control. The inclusion of these sensor data preprocessing functions onboard the spacecraft will significantly improve the extraction of information from the sensor data in a timely and cost effective manner, and provide the opportunity to design sensor systems which can be reconfigured in near real-time for optimum performance. The purpose of this paper is to present the preliminary design of the IAS and the plans for its development.

  15. Adaptive techniques for troposcatter

    NASA Astrophysics Data System (ADS)

    Wallace, M. S.; Parl, S. A.; Malaga, A.; Pierce, J. N.

    1984-02-01

    This report examines the performance of phased array antennas with adaptive combining for troposcatter communications. Diversity is commonly employed to combat fading on troposcatter links. Diversity may be derived from a phased array by adaptive combining of the element outputs (space diversity) or equivalently by forming a set of beams via a Butler matrix transformation (angle diversity). A number of new results describing the performance of both azimuth and elevation angle diversity systems using phased arrays are derived and performance bounds for both azimuth and elevation diversity are found. A new class of sub-optimal combiners is examined. The effect of implicit diversity on wideband systems is considered. The degradation due to channel measurement errors is also determined. A measurement program is proposed to verify the results. The computer program which performs the common volume integration is described.

  16. Adaptive control for accelerators

    DOEpatents

    Eaton, Lawrie E.; Jachim, Stephen P.; Natter, Eckard F.

    1991-01-01

    An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.

  17. Adaptive Structures Flight Experiments

    NASA Technical Reports Server (NTRS)

    Martin, Maurice

    1992-01-01

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  18. Adaptive structures flight experiments

    NASA Astrophysics Data System (ADS)

    Martin, Maurice

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  19. Adaptive aperture synthesis

    NASA Astrophysics Data System (ADS)

    Johnson, A. M.; Zhang, S.; Mudassar, A.; Love, G. D.; Greenaway, A. H.

    2005-12-01

    High-resolution imaging can be achieved by optical aperture synthesis (OAS). Such an imaging process is subject to aberrations introduced by instrumental defects and/or turbulent media. Redundant spacings calibration (RSC) is a snapshot calibration technique that can be used to calibrate OAS arrays without use of assumptions about the object being imaged. Here we investigate the analogies between RSC and adaptive optics in passive imaging applications.

  20. Adaptive optics ophthalmoscopy.

    PubMed

    Roorda, Austin; Duncan, Jacque L

    2015-11-01

    This review starts with a brief history and description of adaptive optics (AO) technology, followed by a showcase of the latest capabilities of AO systems for imaging the human retina and an extensive review of the literature on where AO is being used clinically. The review concludes with a discussion on future directions and guidance on usage and interpretation of images from AO systems for the eye.

  1. Adaptive Decentralized Control

    DTIC Science & Technology

    1985-04-01

    computational requirements and response time provide strong incentives for the use of distributed control architectures. The basic focus of our research is on...ADCON (for Adaptive Decentralized CONtrol) comes from the following observations about the current status of control theory . An important aspect of...decentralized control of completely known systems still has many unresolved issues and some basic problems are yet to be answered. Under these conditions

  2. Reconfigurable environmentally adaptive computing

    NASA Technical Reports Server (NTRS)

    Coxe, Robin L. (Inventor); Galica, Gary E. (Inventor)

    2008-01-01

    Described are methods and apparatus, including computer program products, for reconfigurable environmentally adaptive computing technology. An environmental signal representative of an external environmental condition is received. A processing configuration is automatically selected, based on the environmental signal, from a plurality of processing configurations. A reconfigurable processing element is reconfigured to operate according to the selected processing configuration. In some examples, the environmental condition is detected and the environmental signal is generated based on the detected condition.

  3. Adaptive optics ophthalmoscopy

    PubMed Central

    Roorda, Austin; Duncan, Jacque L.

    2016-01-01

    This review starts with a brief history and description of adaptive optics (AO) technology, followed by a showcase of the latest capabilities of AO systems for imaging the human retina and an extensive review of the literature on where AO is being used clinically. The review concludes with a discussion on future directions and guidance on usage and interpretation of images from AO systems for the eye. PMID:26973867

  4. Adaptive hierarchical fuzzy controller

    SciTech Connect

    Raju, G.V.S.; Jun Zhou

    1993-07-01

    A methodology for designing adaptive hierarchical fuzzy controllers is presented. In order to evaluate this concept, several suitable performance indices were developed and converted to linguistic fuzzy variables. Based on those variables, a supervisory fuzzy rule set was constructed and used to change the parameters of a hierarchical fuzzy controller to accommodate the variations of system parameters. The proposed algorithm was used in feedwater flow control to a steam generator. Simulation studies are presented that illustrate the effectiveness of the approach

  5. Adaptive Biomedical Innovation.

    PubMed

    Honig, P K; Hirsch, G

    2016-12-01

    Adaptive Biomedical Innovation (ABI) is a multistakeholder approach to product and process innovation aimed at accelerating the delivery of clinical value to patients and society. ABI offers the opportunity to transcend the fragmentation and linearity of decision-making in our current model and create a common collaborative framework that optimizes the benefit and access of new medicines for patients as well as creating a more sustainable innovation ecosystem.

  6. MITRE Adaptive Processing Capability

    DTIC Science & Technology

    1994-06-01

    gathering, Funded Research and Development transfer, processing , and interpretation of Center (FFRDC) under the primary data are provided. A strong state-of...1988: Unisys Reston Technology Center, Reston, VA Dr. Bronez was a Member of the Technical Staff. He performed research on signal processing and... processing , mathematical research , and sensor array processing . He was Project Leader and Principal Investigator for projects in adaptive beamforming

  7. Adaptive continuous twisting algorithm

    NASA Astrophysics Data System (ADS)

    Moreno, Jaime A.; Negrete, Daniel Y.; Torres-González, Victor; Fridman, Leonid

    2016-09-01

    In this paper, an adaptive continuous twisting algorithm (ACTA) is presented. For double integrator, ACTA produces a continuous control signal ensuring finite time convergence of the states to zero. Moreover, the control signal generated by ACTA compensates the Lipschitz perturbation in finite time, i.e. its value converges to the opposite value of the perturbation. ACTA also keeps its convergence properties, even in the case that the upper bound of the derivative of the perturbation exists, but it is unknown.

  8. Vestibulospinal adaptation to microgravity

    NASA Technical Reports Server (NTRS)

    Paloski, W. H.

    1998-01-01

    Human balance control is known to be transiently disrupted after spaceflight; however, the mechanisms responsible for postflight postural ataxia are still under investigation. In this report, we propose a conceptual model of vestibulospinal adaptation based on theoretical adaptive control concepts and supported by the results from a comprehensive study of balance control recovery after spaceflight. The conceptual model predicts that immediately after spaceflight the balance control system of a returning astronaut does not expect to receive gravity-induced afferent inputs and that descending vestibulospinal control of balance is disrupted until the central nervous system is able to cope with the newly available vestibular otolith information. Predictions of the model are tested using data from a study of the neurosensory control of balance in astronauts immediately after landing. In that study, the mechanisms of sensorimotor balance control were assessed under normal, reduced, and/or altered (sway-referenced) visual and somatosensory input conditions. We conclude that the adaptive control model accurately describes the neurobehavioral responses to spaceflight and that similar models of altered sensory, motor, or environmental constraints are needed clinically to predict responses that patients with sensorimotor pathologies may have to various visual-vestibular or changing stimulus environments.

  9. Adaptive building skin structures

    NASA Astrophysics Data System (ADS)

    Del Grosso, A. E.; Basso, P.

    2010-12-01

    The concept of adaptive and morphing structures has gained considerable attention in the recent years in many fields of engineering. In civil engineering very few practical applications are reported to date however. Non-conventional structural concepts like deployable, inflatable and morphing structures may indeed provide innovative solutions to some of the problems that the construction industry is being called to face. To give some examples, searches for low-energy consumption or even energy-harvesting green buildings are amongst such problems. This paper first presents a review of the above problems and technologies, which shows how the solution to these problems requires a multidisciplinary approach, involving the integration of architectural and engineering disciplines. The discussion continues with the presentation of a possible application of two adaptive and dynamically morphing structures which are proposed for the realization of an acoustic envelope. The core of the two applications is the use of a novel optimization process which leads the search for optimal solutions by means of an evolutionary technique while the compatibility of the resulting configurations of the adaptive envelope is ensured by the virtual force density method.

  10. Vestibulospinal adaptation to microgravity

    NASA Technical Reports Server (NTRS)

    Paloski, W. H.

    1998-01-01

    Human balance control is known to be transiently disrupted after spaceflight; however, the mechanisms responsible for postflight postural ataxia are still under investigation. In this report, we propose a conceptual model of vestibulospinal adaptation based on theoretical adaptive control concepts and supported by the results from a comprehensive study of balance control recovery after spaceflight. The conceptual model predicts that immediately after spaceflight the balance control system of a returning astronaut does not expect to receive gravity-induced afferent inputs and that descending vestibulospinal control of balance is disrupted until the central nervous system is able to cope with the newly available vestibular otolith information. Predictions of the model are tested using data from a study of the neurosensory control of balance in astronauts immediately after landing. In that study, the mechanisms of sensorimotor balance control were assessed under normal, reduced, and/or altered (sway-referenced) visual and somatosensory input conditions. We conclude that the adaptive control model accurately describes the neurobehavioral responses to spaceflight and that similar models of altered sensory, motor, or environmental constraints are needed clinically to predict responses that patients with sensorimotor pathologies may have to various visual-vestibular or changing stimulus environments.

  11. Adaptive Signal Processing Testbed

    NASA Astrophysics Data System (ADS)

    Parliament, Hugh A.

    1991-09-01

    The design and implementation of a system for the acquisition, processing, and analysis of signal data is described. The initial application for the system is the development and analysis of algorithms for excision of interfering tones from direct sequence spread spectrum communication systems. The system is called the Adaptive Signal Processing Testbed (ASPT) and is an integrated hardware and software system built around the TMS320C30 chip. The hardware consists of a radio frequency data source, digital receiver, and an adaptive signal processor implemented on a Sun workstation. The software components of the ASPT consists of a number of packages including the Sun driver package; UNIX programs that support software development on the TMS320C30 boards; UNIX programs that provide the control, user interaction, and display capabilities for the data acquisition, processing, and analysis components of the ASPT; and programs that perform the ASPT functions including data acquisition, despreading, and adaptive filtering. The performance of the ASPT system is evaluated by comparing actual data rates against their desired values. A number of system limitations are identified and recommendations are made for improvements.

  12. Adaptive Dynamic Bayesian Networks

    SciTech Connect

    Ng, B M

    2007-10-26

    A discrete-time Markov process can be compactly modeled as a dynamic Bayesian network (DBN)--a graphical model with nodes representing random variables and directed edges indicating causality between variables. Each node has a probability distribution, conditional on the variables represented by the parent nodes. A DBN's graphical structure encodes fixed conditional dependencies between variables. But in real-world systems, conditional dependencies between variables may be unknown a priori or may vary over time. Model errors can result if the DBN fails to capture all possible interactions between variables. Thus, we explore the representational framework of adaptive DBNs, whose structure and parameters can change from one time step to the next: a distribution's parameters and its set of conditional variables are dynamic. This work builds on recent work in nonparametric Bayesian modeling, such as hierarchical Dirichlet processes, infinite-state hidden Markov networks and structured priors for Bayes net learning. In this paper, we will explain the motivation for our interest in adaptive DBNs, show how popular nonparametric methods are combined to formulate the foundations for adaptive DBNs, and present preliminary results.

  13. Accelerated Adaptive Integration Method

    PubMed Central

    2015-01-01

    Conformational changes that occur upon ligand binding may be too slow to observe on the time scales routinely accessible using molecular dynamics simulations. The adaptive integration method (AIM) leverages the notion that when a ligand is either fully coupled or decoupled, according to λ, barrier heights may change, making some conformational transitions more accessible at certain λ values. AIM adaptively changes the value of λ in a single simulation so that conformations sampled at one value of λ seed the conformational space sampled at another λ value. Adapting the value of λ throughout a simulation, however, does not resolve issues in sampling when barriers remain high regardless of the λ value. In this work, we introduce a new method, called Accelerated AIM (AcclAIM), in which the potential energy function is flattened at intermediate values of λ, promoting the exploration of conformational space as the ligand is decoupled from its receptor. We show, with both a simple model system (Bromocyclohexane) and the more complex biomolecule Thrombin, that AcclAIM is a promising approach to overcome high barriers in the calculation of free energies, without the need for any statistical reweighting or additional processors. PMID:24780083

  14. Cold-Adapted Enzymes

    NASA Astrophysics Data System (ADS)

    Georlette, D.; Bentahir, M.; Claverie, P.; Collins, T.; D'amico, S.; Delille, D.; Feller, G.; Gratia, E.; Hoyoux, A.; Lonhienne, T.; Meuwis, M.-a.; Zecchinon, L.; Gerday, Ch.

    In the last few years, increased attention has been focused on enzymes produced by cold-adapted micro-organisms. It has emerged that psychrophilic enzymes represent an extremely powerful tool in both protein folding investigations and for biotechnological purposes. Such enzymes are characterised by an increased thermosensitivity and, most of them, by a higher catalytic efficiency at low and moderate temperatures, when compared to their mesophilic counterparts. The high thermosensitivity probably originates from an increased flexibility of either a selected area of the molecular edifice or the overall protein structure, providing enhanced abilities to undergo conformational changes during catalysis at low temperatures. Structure modelling and recent crystallographic data have allowed to elucidate the structural parameters that could be involved in this higher resilience. It was demonstrated that each psychrophilic enzyme adopts its own adaptive strategy. It appears, moreover, that there is a continuum in the strategy of protein adaptation to temperature, as the previously mentioned structural parameters are implicated in the stability of thermophilic proteins. Additional 3D crystal structures, site-directed and random mutagenesis experiments should now be undertaken to further investigate the stability-flexibility-activity relationship.

  15. Adaptive colouration in amphibians.

    PubMed

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians.

  16. Stasis and adaptation.

    PubMed

    Coiera, Enrico

    2013-01-01

    Many of our most pressing societal challenges arise from our inability to move on from present practices and structures and do what is needed. Healthcare struggles to improve safety and quality. It resists adoption of best practices and persists in high levels of unwarranted variation in care delivery, and clings to financially unsustainable models of care. One explanation for this state of affairs is not a lack of will, but that we are experiencing system inertia--a consequence of the increasing complexity of our human systems. In this paper I explore three possible system level interventions that may help design systems that are less likely to approach inertia, as well as help change our current systems so that they again become adaptive, and move to the outcomes we desire. Firstly, I question our religious belief in the power of standards, an intervention designed to minimise adaptation and almost from first principles designed to lead to inertia. Next I explore the power of apoptosis, a process that sees existing structures and practices programmatically removed to free up resource for adaptation. Finally I explore a flexible but controversial approach to system management called market-based control. Whether any of these, together or in tandem, are a way out of inertia is an open question. However, it is time for us to engage with the challenge of system inertia, and find a way out.

  17. Advanced Adaptive Optics Control Techniques

    DTIC Science & Technology

    1979-01-01

    Optimal estimation and control methods for high energy laser adaptive optics systems are described. Three system types are examined: Active...the adaptive optics approaches and potential system implementations are recommended.

  18. Multidimensional Adaptation in MAS Organizations.

    PubMed

    Alberola, Juan M; Julian, Vicente; Garcia-Fornes, Ana

    2013-04-01

    Organization adaptation requires determining the consequences of applying changes not only in terms of the benefits provided but also measuring the adaptation costs as well as the impact that these changes have on all of the components of the organization. In this paper, we provide an approach for adaptation in multiagent systems based on a multidimensional transition deliberation mechanism (MTDM). This approach considers transitions in multiple dimensions and is aimed at obtaining the adaptation with the highest potential for improvement in utility based on the costs of adaptation. The approach provides an accurate measurement of the impact of the adaptation since it determines the organization that is to be transitioned to as well as the changes required to carry out this transition. We show an example of adaptation in a service provider network environment in order to demonstrate that the measurement of the adaptation consequences taken by the MTDM improves the organization performance more than the other approaches.

  19. Advanced Adaptive Optics Technology Development

    SciTech Connect

    Olivier, S

    2001-09-18

    The NSF Center for Adaptive Optics (CfAO) is supporting research on advanced adaptive optics technologies. CfAO research activities include development and characterization of micro-electro-mechanical systems (MEMS) deformable mirror (DM) technology, as well as development and characterization of high-resolution adaptive optics systems using liquid crystal (LC) spatial light modulator (SLM) technology. This paper presents an overview of the CfAO advanced adaptive optics technology development activities including current status and future plans.

  20. Theory of psychological adaptive modes.

    PubMed

    Lehti, Juha

    2016-05-01

    When an individual is facing a stressor and normal stress-response mechanism cannot guarantee sufficient adaptation, special emotional states, adaptive modes, are activated (for example a depressive reaction). Adaptive modes are involuntary states of mind, they are of comprehensive nature, they interfere with normal functioning, and they cannot be repressed or controlled the same way as many emotions. Their transformational nature differentiates them from other emotional states. The object of the adaptive mode is to optimize the problem-solving abilities according to the situation that has provoked the mode. Cognitions and emotions during the adaptive mode are different than in a normal mental state. These altered cognitions and emotional reactions guide the individual to use the correct coping skills in order to deal with the stressor. Successful adaptation will cause the adaptive mode to fade off since the adaptive mode is no longer necessary, and the process as a whole will lead to raised well-being. However, if the adaptation process is inadequate, then the transformation period is prolonged, and the adaptive mode will turn into a dysfunctional state. Many psychiatric disorders are such maladaptive processes. The maladaptive processes can be turned into functional ones by using adaptive skills that are used in functional adaptive processes.

  1. Lateral Spreading of Visual Adaptation,

    DTIC Science & Technology

    1982-03-02

    adapting field. 2.4X10- 3 footlamberts to simulate the luminance of In studying the spreading of adaptational ef- grass on a clear night with a full ... moon . fects (sensitivity changes) to areas outside of the adaptational field we are also interested in discovering the mechanisms which produce such a

  2. Adaptive Control of Innate Immunity

    PubMed Central

    Shanker, Anil

    2010-01-01

    1. Summary The mechanisms by which the immune system responds to an infection or disease depend on a complex interplay between the elements of innate and adaptive immunity. While most of the focus so far has been on the innate instruction of the adaptive immune responses, considerable evidence now suggests an equally important adaptive control of the innate immunity. Several studies yield new insights into how the adaptive immunity by initiating an antigen–specific response can compensate, suppress and activate innate responses at the site of tissue antigen. Here we discuss recent advances in our understanding of the adaptive control of immune effector functions in various pathological and physiological conditions. PMID:20394777

  3. Adaptive nonlinear flight control

    NASA Astrophysics Data System (ADS)

    Rysdyk, Rolf Theoduor

    1998-08-01

    Research under supervision of Dr. Calise and Dr. Prasad at the Georgia Institute of Technology, School of Aerospace Engineering. has demonstrated the applicability of an adaptive controller architecture. The architecture successfully combines model inversion control with adaptive neural network (NN) compensation to cancel the inversion error. The tiltrotor aircraft provides a specifically interesting control design challenge. The tiltrotor aircraft is capable of converting from stable responsive fixed wing flight to unstable sluggish hover in helicopter configuration. It is desirable to provide the pilot with consistency in handling qualities through a conversion from fixed wing flight to hover. The linear model inversion architecture was adapted by providing frequency separation in the command filter and the error-dynamics, while not exiting the actuator modes. This design of the architecture provides for a model following setup with guaranteed performance. This in turn allowed for convenient implementation of guaranteed handling qualities. A rigorous proof of boundedness is presented making use of compact sets and the LaSalle-Yoshizawa theorem. The analysis allows for the addition of the e-modification which guarantees boundedness of the NN weights in the absence of persistent excitation. The controller is demonstrated on the Generic Tiltrotor Simulator of Bell-Textron and NASA Ames R.C. The model inversion implementation is robustified with respect to unmodeled input dynamics, by adding dynamic nonlinear damping. A proof of boundedness of signals in the system is included. The effectiveness of the robustification is also demonstrated on the XV-15 tiltrotor. The SHL Perceptron NN provides a more powerful application, based on the universal approximation property of this type of NN. The SHL NN based architecture is also robustified with the dynamic nonlinear damping. A proof of boundedness extends the SHL NN augmentation with robustness to unmodeled actuator

  4. Adaptation in Collaborative Governance Regimes

    NASA Astrophysics Data System (ADS)

    Emerson, Kirk; Gerlak, Andrea K.

    2014-10-01

    Adaptation and the adaptive capacity of human and environmental systems have been of central concern to natural and social science scholars, many of whom characterize and promote the need for collaborative cross-boundary systems that are seen as flexible and adaptive by definition. Researchers who study collaborative governance systems in the public administration, planning and policy literature have paid less attention to adaptive capacity specifically and institutional adaptation in general. This paper bridges the two literatures and finds four common dimensions of capacity, including structural arrangements, leadership, knowledge and learning, and resources. In this paper, we focus on institutional adaptation in the context of collaborative governance regimes and try to clarify and distinguish collaborative capacity from adaptive capacity and their contributions to adaptive action. We posit further that collaborative capacities generate associated adaptive capacities thereby enabling institutional adaptation within collaborative governance regimes. We develop these distinctions and linkages between collaborative and adaptive capacities with the help of an illustrative case study in watershed management within the National Estuary Program.

  5. Adaptation in collaborative governance regimes.

    PubMed

    Emerson, Kirk; Gerlak, Andrea K

    2014-10-01

    Adaptation and the adaptive capacity of human and environmental systems have been of central concern to natural and social science scholars, many of whom characterize and promote the need for collaborative cross-boundary systems that are seen as flexible and adaptive by definition. Researchers who study collaborative governance systems in the public administration, planning and policy literature have paid less attention to adaptive capacity specifically and institutional adaptation in general. This paper bridges the two literatures and finds four common dimensions of capacity, including structural arrangements, leadership, knowledge and learning, and resources. In this paper, we focus on institutional adaptation in the context of collaborative governance regimes and try to clarify and distinguish collaborative capacity from adaptive capacity and their contributions to adaptive action. We posit further that collaborative capacities generate associated adaptive capacities thereby enabling institutional adaptation within collaborative governance regimes. We develop these distinctions and linkages between collaborative and adaptive capacities with the help of an illustrative case study in watershed management within the National Estuary Program.

  6. Renal adaptation during hibernation.

    PubMed

    Jani, Alkesh; Martin, Sandra L; Jain, Swati; Keys, Daniel; Edelstein, Charles L

    2013-12-01

    Hibernators periodically undergo profound physiological changes including dramatic reductions in metabolic, heart, and respiratory rates and core body temperature. This review discusses the effect of hypoperfusion and hypothermia observed during hibernation on glomerular filtration and renal plasma flow, as well as specific adaptations in renal architecture, vasculature, the renin-angiotensin system, and upregulation of possible protective mechanisms during the extreme conditions endured by hibernating mammals. Understanding the mechanisms of protection against organ injury during hibernation may provide insights into potential therapies for organ injury during cold storage and reimplantation during transplantation.

  7. Adaptive Algebraic Smoothers

    SciTech Connect

    Philip, Bobby; Chartier, Dr Timothy

    2012-01-01

    methods based on Local Sensitivity Analysis (LSA). The method can be used in the context of geometric and algebraic multigrid methods for constructing smoothers, and in the context of Krylov methods for constructing block preconditioners. It is suitable for both constant and variable coecient problems. Furthermore, the method can be applied to systems arising from both scalar and coupled system partial differential equations (PDEs), as well as linear systems that do not arise from PDEs. The simplicity of the method will allow it to be easily incorporated into existing multigrid and Krylov solvers while providing a powerful tool for adaptively constructing methods tuned to a problem.

  8. Adaptive Optical Scanning Holography

    PubMed Central

    Tsang, P. W. M.; Poon, Ting-Chung; Liu, J.-P.

    2016-01-01

    Optical Scanning Holography (OSH) is a powerful technique that employs a single-pixel sensor and a row-by-row scanning mechanism to capture the hologram of a wide-view, three-dimensional object. However, the time required to acquire a hologram with OSH is rather lengthy. In this paper, we propose an enhanced framework, which is referred to as Adaptive OSH (AOSH), to shorten the holographic recording process. We have demonstrated that the AOSH method is capable of decreasing the acquisition time by up to an order of magnitude, while preserving the content of the hologram favorably. PMID:26916866

  9. Adaptive CT scanning system

    SciTech Connect

    Sampayan, Stephen E.

    2016-11-22

    Apparatus, systems, and methods that provide an X-ray interrogation system having a plurality of stationary X-ray point sources arranged to substantially encircle an area or space to be interrogated. A plurality of stationary detectors are arranged to substantially encircle the area or space to be interrogated, A controller is adapted to control the stationary X-ray point sources to emit X-rays one at a time, and to control the stationary detectors to detect the X-rays emitted by the stationary X-ray point sources.

  10. Adaptive Optical Scanning Holography

    NASA Astrophysics Data System (ADS)

    Tsang, P. W. M.; Poon, Ting-Chung; Liu, J.-P.

    2016-02-01

    Optical Scanning Holography (OSH) is a powerful technique that employs a single-pixel sensor and a row-by-row scanning mechanism to capture the hologram of a wide-view, three-dimensional object. However, the time required to acquire a hologram with OSH is rather lengthy. In this paper, we propose an enhanced framework, which is referred to as Adaptive OSH (AOSH), to shorten the holographic recording process. We have demonstrated that the AOSH method is capable of decreasing the acquisition time by up to an order of magnitude, while preserving the content of the hologram favorably.

  11. Holographic Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Andersen, G.

    For the last two decades adaptive optics has been used as a technique for correcting imaging applications and directed energy/laser targeting and laser communications systems affected by atmospheric turbulence. Typically these systems are bulky and limited to <10 kHz due to large computing overhead and limited photon efficiencies. Moreover most use zonal wavefront sensors which cannot easily handle extreme scintillation or unexpected obscuration of a pre-set aperture. Here we present a compact, lightweight adaptive optics system with the potential to operate at speeds of MHz. The system utilizes a hologram to perform an all-optical wavefront analysis that removes the need for any computer. Finally, the sensing is made on a modal basis so it is largely insensitive to scintillation and obscuration. We have constructed a prototype device and will present experimental results from our research. The holographic adaptive optics system begins with the creation of a multiplexed hologram. This hologram is created by recording the maximum and minimum response functions of every actuator in the deformable mirror against a unique focused reference beam. When a wavefront of some arbitrary phase is incident on the processed hologram, a number of focal spots are created -- one pair for each actuator in the DM. The absolute phase error at each particular actuator location is simply related to the ratio of the intensity of each pair of spots. In this way we can use an array of photodetectors to give a direct readout of phase error without the need for any calculations. The advantages of holographic adaptive optics are many. To begin with, the measurement of phase error is made all optically, so the wavefront sensor directly controls the actuators in the DM without any computers. Using fast, photon counting photodetectors allows for closed loop correction limited only by the speed of the deformable mirror which in the case of MEMS devices can be 100 kHz or more. All this can be

  12. Cardiovascular adaptation in athletes.

    PubMed

    Kovacs, Richard; Baggish, Aaron L

    2016-01-01

    Millions of athletes train for and participate in competitive athletics each year. Many of these athletes will present to a cardiovascular specialist with signs or symptoms that might indicate heart disease and these athletes/patients will ask for advice on their ability to continue to train and compete safely. By virtue of their training, athletes׳ hearts may undergo significant structural and electrical change, presenting a special challenge for the cardiovascular specialist. It is important to understand normal adaptive changes in order to separate normal physiology from pathology.

  13. Laser adaptive holographic hydrophone

    SciTech Connect

    Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A

    2016-03-31

    A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)

  14. Renal adaptation during hibernation

    PubMed Central

    Martin, Sandra L.; Jain, Swati; Keys, Daniel; Edelstein, Charles L.

    2013-01-01

    Hibernators periodically undergo profound physiological changes including dramatic reductions in metabolic, heart, and respiratory rates and core body temperature. This review discusses the effect of hypoperfusion and hypothermia observed during hibernation on glomerular filtration and renal plasma flow, as well as specific adaptations in renal architecture, vasculature, the renin-angiotensin system, and upregulation of possible protective mechanisms during the extreme conditions endured by hibernating mammals. Understanding the mechanisms of protection against organ injury during hibernation may provide insights into potential therapies for organ injury during cold storage and reimplantation during transplantation. PMID:24049148

  15. Classifying climate change adaptation frameworks

    NASA Astrophysics Data System (ADS)

    Armstrong, Jennifer

    2014-05-01

    Complex socio-ecological demographics are factors that must be considered when addressing adaptation to the potential effects of climate change. As such, a suite of deployable climate change adaptation frameworks is necessary. Multiple frameworks that are required to communicate the risks of climate change and facilitate adaptation. Three principal adaptation frameworks have emerged from the literature; Scenario - Led (SL), Vulnerability - Led (VL) and Decision - Centric (DC). This study aims to identify to what extent these adaptation frameworks; either, planned or deployed are used in a neighbourhood vulnerable to climate change. This work presents a criterion that may be used as a tool for identifying the hallmarks of adaptation frameworks and thus enabling categorisation of projects. The study focussed on the coastal zone surrounding the Sizewell nuclear power plant in Suffolk in the UK. An online survey was conducted identifying climate change adaptation projects operating in the study area. This inventory was analysed to identify the hallmarks of each adaptation project; Levels of dependency on climate model information, Metrics/units of analysis utilised, Level of demographic knowledge, Level of stakeholder engagement, Adaptation implementation strategies and Scale of adaptation implementation. The study found that climate change adaptation projects could be categorised, based on the hallmarks identified, in accordance with the published literature. As such, the criterion may be used to establish the matrix of adaptation frameworks present in a given area. A comprehensive summary of the nature of adaptation frameworks in operation in a locality provides a platform for further comparative analysis. Such analysis, enabled by the criterion, may aid the selection of appropriate frameworks enhancing the efficacy of climate change adaptation.

  16. Adaptive multifunctional composites

    NASA Astrophysics Data System (ADS)

    Wang, Ya; Inman, Daniel J.

    2013-05-01

    The adaptive multifunctional composite structure studied here is to address two issues remaining in lightweight structural composites required by many engineering applications. The first is to add additional functionality to multifunctional composites and the second is to provide adaptive damping in structures that cover a wide range of frequencies and temperatures. Because of its potential for practical payoffs, passive structural damping can find wide application through the use of high-damping viscoelastic polymers or elastomers. However, all passive damping using these damping materials suffer from failing at certain temperatures and in certain frequency ranges. The extreme environments often seen by engineering systems provide high temperature, which is exactly where damping levels in structures reduce causing unacceptable vibrations. In addition, as loading frequencies reduce damping levels also fall off, and many loads experienced by large structures are low frequency. The proposed research addresses increasing the range of effectiveness of damping by addressing the temperature and frequency dependence of material damping by using a multifunctional composite system containing an active element. Previous research has yielded a finite element model of linear viscoelastic material and structural behavior that captures characteristic frequency-dependent behavior, continuing research has addressed the accommodation of temperature dependence, and the examination of the new concept of `electronic damping' or `e-damping'. The resulting modeling approach is validated through experimental validation.

  17. Axioms of adaptivity

    PubMed Central

    Carstensen, C.; Feischl, M.; Page, M.; Praetorius, D.

    2014-01-01

    This paper aims first at a simultaneous axiomatic presentation of the proof of optimal convergence rates for adaptive finite element methods and second at some refinements of particular questions like the avoidance of (discrete) lower bounds, inexact solvers, inhomogeneous boundary data, or the use of equivalent error estimators. Solely four axioms guarantee the optimality in terms of the error estimators. Compared to the state of the art in the temporary literature, the improvements of this article can be summarized as follows: First, a general framework is presented which covers the existing literature on optimality of adaptive schemes. The abstract analysis covers linear as well as nonlinear problems and is independent of the underlying finite element or boundary element method. Second, efficiency of the error estimator is neither needed to prove convergence nor quasi-optimal convergence behavior of the error estimator. In this paper, efficiency exclusively characterizes the approximation classes involved in terms of the best-approximation error and data resolution and so the upper bound on the optimal marking parameters does not depend on the efficiency constant. Third, some general quasi-Galerkin orthogonality is not only sufficient, but also necessary for the R-linear convergence of the error estimator, which is a fundamental ingredient in the current quasi-optimality analysis due to Stevenson 2007. Finally, the general analysis allows for equivalent error estimators and inexact solvers as well as different non-homogeneous and mixed boundary conditions. PMID:25983390

  18. Insect--plant adaptations.

    PubMed

    Southwood, T R

    1984-01-01

    The adaptation of insects to plants probably commenced in the early Permian period, though most current associations will be more recent. A major burst of adaptation must have followed the rise of the Angiosperms in the Cretaceous period, though some particular associations are as recent as this century. Living plants form a large proportion of the potential food in most habitats, though insects have had to overcome certain general hurdles to live and feed on them. Insects affect the reproduction and survival of plants, and thus the diversity of plant secondary chemicals may have evolved as a response. Where an insect species has a significant effect on a plant species that is its only host, coevolution may be envisaged. A spectacular example is provided by Heliconius butterflies and passion flower vines, studied by L.E. Gilbert and others. But such cases may be likened to 'vortices in the evolutionary stream': most plant species are influenced by a range of phytophagous insects so that selection will be for general defences--a situation termed diffuse coevolution. Evidence is presented on recent host-plant shifts to illustrate both the restrictions and the flexibility in current insect-plant associations.

  19. ADAPTIVE ROBUST VARIABLE SELECTION

    PubMed Central

    Fan, Jianqing; Fan, Yingying; Barut, Emre

    2014-01-01

    Heavy-tailed high-dimensional data are commonly encountered in various scientific fields and pose great challenges to modern statistical analysis. A natural procedure to address this problem is to use penalized quantile regression with weighted L1-penalty, called weighted robust Lasso (WR-Lasso), in which weights are introduced to ameliorate the bias problem induced by the L1-penalty. In the ultra-high dimensional setting, where the dimensionality can grow exponentially with the sample size, we investigate the model selection oracle property and establish the asymptotic normality of the WR-Lasso. We show that only mild conditions on the model error distribution are needed. Our theoretical results also reveal that adaptive choice of the weight vector is essential for the WR-Lasso to enjoy these nice asymptotic properties. To make the WR-Lasso practically feasible, we propose a two-step procedure, called adaptive robust Lasso (AR-Lasso), in which the weight vector in the second step is constructed based on the L1-penalized quantile regression estimate from the first step. This two-step procedure is justified theoretically to possess the oracle property and the asymptotic normality. Numerical studies demonstrate the favorable finite-sample performance of the AR-Lasso. PMID:25580039

  20. Adaptive lung ventilation.

    PubMed

    Linton, D M

    2001-09-01

    Adaptive lung ventilation (ALV) is a method of closed-loop mechanical ventilation analogous to modern closed-loop technology in aviation such as the autopilot and automatic landing system. The algorithm of the controller of ALV is designed to automatically provide pressure-controlled synchronized intermittent mandatory ventilation (P-SIMV) and weaning as individually required in any clinical situation. The synchronized pressure limited breaths constantly adapt to the patient requirements to encourage optimal alveolar ventilation with minimal adverse physiological disturbance and timely weaning. The ease of application, efficiency, and safety of the first ALV controllers have been demonstrated in lung models, in patients with normal lungs undergoing general anesthesia, in patients requiring unusual positioning, in transition to and from one-lung anesthesia, and in long-term ventilation of patients with various lung pathologies and in weaning patients who have restrictive or obstructive pulmonary disease. Prospective comparative studies of ALV versus other currently used manually selected modes of mechanical ventilation, such as the one reported in this article, should confirm the safety and identify the benefits of this form of advanced closed-loop mechanical ventilation technology.

  1. Geoengineering and adaptation

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2010-12-01

    Geoengineering by carbon capture and storage (CCS) or solar radiation management (SRM) has been suggested as a possible solution to global warming. However, it is clear that mitigation should be the main response of society, quickly reducing emissions of greenhouse gases. While there is no concerted mitigation effort yet, even if the world moves quickly to reduce emissions, the gases that are already in the atmosphere will continue to warm the planet. CCS, if a system that is efficacious, safe, and not costly could be developed, would slowly remove CO2 from the atmosphere, but this will have a gradual effect on concentrations. SRM, if a system could be developed to produce stratospheric aerosols or brighten marine stratocumulus clouds, could be quickly effective in cooling, but could also have so many negative side effects that it would be better not do it at all. This means that, in spite of a concerted effort at mitigation and to develop CCS, there will be a certain amount of global warming in our future. Because CCS geoengineering will be too slow and SRM geoengineering is not a practical or safe solution to geoengineering, adaptation will be needed. Our current understanding of geoengineering makes it even more important to focus on adaptation responses to global warming.

  2. Adaptive infrared target detection

    NASA Astrophysics Data System (ADS)

    McBride, Jonah C.; Stevens, Mark R.; Eaton, Ross S.; Snorrason, Magnus S.

    2004-09-01

    Automatic Target Recognition (ATR) algorithms are extremely sensitive to differences between the operating conditions under which they are trained and the extended operating conditions (EOCs) in which the fielded algorithms are tested. These extended operating conditions can cause a target's signature to be drastically different from training exemplars/models. For example, a target's signature can be influenced by: the time of day, the time of year, the weather, atmospheric conditions, position of the sun or other illumination sources, the target surface and material properties, the target composition, the target geometry, sensor characteristics, sensor viewing angle and range, the target surroundings and environment, and the target and scene temperature. Recognition rates degrade if an ATR is not trained for a particular EOC. Most infrared target detection techniques are based on a very simple probabilistic theory. This theory states that a pixel should be assigned the label of "target" if a set of measurements (features) is more likely to have come from an assumed (or learned) distribution of target features than from the distribution of background features. However, most detection systems treat these learned distributions as static and they are not adapted to changing EOCs. In this paper, we present an algorithm for assigning a pixel the label of target or background based on a statistical comparison of the distributions of measurements surrounding that pixel in the image. This method provides a feature-level adaptation to changing EOCs. Results are demonstrated on infrared imagery containing several military vehicles.

  3. Adaptive Caching Concept

    NASA Image and Video Library

    2015-06-10

    This diagram, superimposed on a photo of Martian landscape, illustrates a concept called "adaptive caching," which is in development for NASA's 2020 Mars rover mission. In addition to the investigations that the Mars 2020 rover will conduct on Mars, the rover will collect carefully selected samples of Mars rock and soil and cache them to be available for possible return to Earth if a Mars sample-return mission is scheduled and flown. Each sample will be stored in a sealed tube. Adaptive caching would result in a set of samples, up to the maximum number of tubes carried on the rover, being placed on the surface at the discretion of the mission operators. The tubes holding the collected samples would not go into a surrounding container. In this illustration, green dots indicate "regions of interest," where samples might be collected. The green diamond indicates one region of interest serving as the depot for the cache. The green X at upper right represents the landing site. The solid black line indicates the rover's route during its prime mission, and the dashed black line indicates its route during an extension of the mission. The base image is a portion of the "Everest Panorama" taken by the panoramic camera on NASA's Mars Exploration Rover Spirit at the top of Husband Hill in 2005. http://photojournal.jpl.nasa.gov/catalog/PIA19150

  4. Adaptive EAGLE dynamic solution adaptation and grid quality enhancement

    NASA Technical Reports Server (NTRS)

    Luong, Phu Vinh; Thompson, J. F.; Gatlin, B.; Mastin, C. W.; Kim, H. J.

    1992-01-01

    In the effort described here, the elliptic grid generation procedure in the EAGLE grid code was separated from the main code into a subroutine, and a new subroutine which evaluates several grid quality measures at each grid point was added. The elliptic grid routine can now be called, either by a computational fluid dynamics (CFD) code to generate a new adaptive grid based on flow variables and quality measures through multiple adaptation, or by the EAGLE main code to generate a grid based on quality measure variables through static adaptation. Arrays of flow variables can be read into the EAGLE grid code for use in static adaptation as well. These major changes in the EAGLE adaptive grid system make it easier to convert any CFD code that operates on a block-structured grid (or single-block grid) into a multiple adaptive code.

  5. Saccade Adaptation and Visual Uncertainty

    PubMed Central

    Souto, David; Gegenfurtner, Karl R.; Schütz, Alexander C.

    2016-01-01

    Visual uncertainty may affect saccade adaptation in two complementary ways. First, an ideal adaptor should take into account the reliability of visual information for determining the amount of correction, predicting that increasing visual uncertainty should decrease adaptation rates. We tested this by comparing observers' direction discrimination and adaptation rates in an intra-saccadic-step paradigm. Second, clearly visible target steps may generate a slower adaptation rate since the error can be attributed to an external cause, instead of an internal change in the visuo-motor mapping that needs to be compensated. We tested this prediction by measuring saccade adaptation to different step sizes. Most remarkably, we found little correlation between estimates of visual uncertainty and adaptation rates and no slower adaptation rates with more visible step sizes. Additionally, we show that for low contrast targets backward steps are perceived as stationary after the saccade, but that adaptation rates are independent of contrast. We suggest that the saccadic system uses different position signals for adapting dysmetric saccades and for generating a trans-saccadic stable visual percept, explaining that saccade adaptation is found to be independent of visual uncertainty. PMID:27252635

  6. Auditory adaptation in voice perception.

    PubMed

    Schweinberger, Stefan R; Casper, Christoph; Hauthal, Nadine; Kaufmann, Jürgen M; Kawahara, Hideki; Kloth, Nadine; Robertson, David M C; Simpson, Adrian P; Zäske, Romi

    2008-05-06

    Perceptual aftereffects following adaptation to simple stimulus attributes (e.g., motion, color) have been studied for hundreds of years. A striking recent discovery was that adaptation also elicits contrastive aftereffects in visual perception of complex stimuli and faces [1-6]. Here, we show for the first time that adaptation to nonlinguistic information in voices elicits systematic auditory aftereffects. Prior adaptation to male voices causes a voice to be perceived as more female (and vice versa), and these auditory aftereffects were measurable even minutes after adaptation. By contrast, crossmodal adaptation effects were absent, both when male or female first names and when silently articulating male or female faces were used as adaptors. When sinusoidal tones (with frequencies matched to male and female voice fundamental frequencies) were used as adaptors, no aftereffects on voice perception were observed. This excludes explanations for the voice aftereffect in terms of both pitch adaptation and postperceptual adaptation to gender concepts and suggests that contrastive voice-coding mechanisms may routinely influence voice perception. The role of adaptation in calibrating properties of high-level voice representations indicates that adaptation is not confined to vision but is a ubiquitous mechanism in the perception of nonlinguistic social information from both faces and voices.

  7. Speed adaptation as Kalman filtering.

    PubMed

    Barraza, Jose F; Grzywacz, Norberto M

    2008-10-01

    If the purpose of adaptation is to fit sensory systems to different environments, it may implement an optimization of the system. What the optimum is depends on the statistics of these environments. Therefore, the system should update its parameters as the environment changes. A Kalman-filtering strategy performs such an update optimally by combining current estimations of the environment with those from the past. We investigate whether the visual system uses such a strategy for speed adaptation. We performed a matching-speed experiment to evaluate the time course of adaptation to an abrupt velocity change. Experimental results are in agreement with Kalman-modeling predictions for speed adaptation. When subjects adapt to a low speed and it suddenly increases, the time course of adaptation presents two phases, namely, a rapid decrease of perceived speed followed by a slower phase. In contrast, when speed changes from fast to slow, adaptation presents a single phase. In the Kalman-model simulations, this asymmetry is due to the prevalence of low speeds in natural images. However, this asymmetry disappears both experimentally and in simulations when the adapting stimulus is noisy. In both transitions, adaptation now occurs in a single phase. Finally, the model also predicts the change in sensitivity to speed discrimination produced by the adaptation.

  8. Adaptation improves face trustworthiness discrimination.

    PubMed

    Keefe, B D; Dzhelyova, M; Perrett, D I; Barraclough, N E

    2013-01-01

    Adaptation to facial characteristics, such as gender and viewpoint, has been shown to both bias our perception of faces and improve facial discrimination. In this study, we examined whether adapting to two levels of face trustworthiness improved sensitivity around the adapted level. Facial trustworthiness was manipulated by morphing between trustworthy and untrustworthy prototypes, each generated by morphing eight trustworthy and eight untrustworthy faces, respectively. In the first experiment, just-noticeable differences (JNDs) were calculated for an untrustworthy face after participants adapted to an untrustworthy face, a trustworthy face, or did not adapt. In the second experiment, the three conditions were identical, except that JNDs were calculated for a trustworthy face. In the third experiment we examined whether adapting to an untrustworthy male face improved discrimination to an untrustworthy female face. In all experiments, participants completed a two-interval forced-choice (2-IFC) adaptive staircase procedure, in which they judged which face was more untrustworthy. JNDs were derived from a psychometric function fitted to the data. Adaptation improved sensitivity to faces conveying the same level of trustworthiness when compared to no adaptation. When adapting to and discriminating around a different level of face trustworthiness there was no improvement in sensitivity and JNDs were equivalent to those in the no adaptation condition. The improvement in sensitivity was found to occur even when adapting to a face with different gender and identity. These results suggest that adaptation to facial trustworthiness can selectively enhance mechanisms underlying the coding of facial trustworthiness to improve perceptual sensitivity. These findings have implications for the role of our visual experience in the decisions we make about the trustworthiness of other individuals.

  9. Adaptation improves face trustworthiness discrimination

    PubMed Central

    Keefe, B. D.; Dzhelyova, M.; Perrett, D. I.; Barraclough, N. E.

    2013-01-01

    Adaptation to facial characteristics, such as gender and viewpoint, has been shown to both bias our perception of faces and improve facial discrimination. In this study, we examined whether adapting to two levels of face trustworthiness improved sensitivity around the adapted level. Facial trustworthiness was manipulated by morphing between trustworthy and untrustworthy prototypes, each generated by morphing eight trustworthy and eight untrustworthy faces, respectively. In the first experiment, just-noticeable differences (JNDs) were calculated for an untrustworthy face after participants adapted to an untrustworthy face, a trustworthy face, or did not adapt. In the second experiment, the three conditions were identical, except that JNDs were calculated for a trustworthy face. In the third experiment we examined whether adapting to an untrustworthy male face improved discrimination to an untrustworthy female face. In all experiments, participants completed a two-interval forced-choice (2-IFC) adaptive staircase procedure, in which they judged which face was more untrustworthy. JNDs were derived from a psychometric function fitted to the data. Adaptation improved sensitivity to faces conveying the same level of trustworthiness when compared to no adaptation. When adapting to and discriminating around a different level of face trustworthiness there was no improvement in sensitivity and JNDs were equivalent to those in the no adaptation condition. The improvement in sensitivity was found to occur even when adapting to a face with different gender and identity. These results suggest that adaptation to facial trustworthiness can selectively enhance mechanisms underlying the coding of facial trustworthiness to improve perceptual sensitivity. These findings have implications for the role of our visual experience in the decisions we make about the trustworthiness of other individuals. PMID:23801979

  10. Adaptive SAR ATR problem set (AdaptSAPS)

    NASA Astrophysics Data System (ADS)

    Wise, Angela R.; Fitzgerald, Donna; Ross, Timothy D.

    2004-09-01

    A strong and growing interest in systems that adapt to changing circumstances was evident in panel discussions at the "Algorithms for SAR Imagery" Conference of the AeroSense Symposium in April 2003, with DARPA, Air Force, industry and academia participation. As a result, Conference Co-Chair Mr. Ed Zelnio suggested producing a dynamic model to create problem sets suitable for adaptive system research and development. Such a problem set provides a framework for the overall problem, including organization of operating conditions, performance measures and specific test cases. It is hoped that this AdaptSAPS framework will help provide the community with a more concrete base for discussing adaptation in SAR imagery exploitation. AdaptSAPS Version 1.0 was produced by the AFRL COMPASE and SDMS organizations and posted on 5 August 2003. AdaptSAPS consists of over a dozen MatLab programs that allow the user to create "missions" with SAR data of varying complexities and then present that test data one image at a time, first as unexploited imagery and then later with the exploitation results that an ATR could use for adaptation in an operational environment. AdaptSAPS keeps track of performance results and reports performance measures. This paper describes AdaptSAPS - its application process and possible improvements as a problem set.

  11. Intestinal mucosal atrophy and adaptation.

    PubMed

    Shaw, Darcy; Gohil, Kartik; Basson, Marc D

    2012-11-28

    Mucosal adaptation is an essential process in gut homeostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical outcomes can be improved by manipulating the physiology of adaptation. This review will summarize current understanding of the basic science surrounding adaptation, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clinical outcomes.

  12. Toward reflexive climate adaptation research

    SciTech Connect

    Preston, Benjamin L.; Rickards, Lauren; Fünfgeld, Hartmut; Keenan, Rodney J.

    2015-06-22

    Climate adaptation research is expanding very quickly within an increasingly reflexive society where the relationship between academia and other social institutions is in a state of flux. Tensions exist between the two dominant research orientations of research about and research for adaptation. In particular, the research community is challenged to develop processes for successfully executing transdisciplinary research for adaptation when academic institutions and researchers are largely structured around traditional, disciplinary expertise and funding models. One tool for helping to manage this tension is a third, more reflexive, orientation toward adaptation research that is emerging in the literature. Finally, this new ‘research on adaptation research’ promises to help enhance understanding of the research enterprise itself and how it can become more adaptive.

  13. Toward reflexive climate adaptation research

    DOE PAGES

    Preston, Benjamin L.; Rickards, Lauren; Fünfgeld, Hartmut; ...

    2015-06-22

    Climate adaptation research is expanding very quickly within an increasingly reflexive society where the relationship between academia and other social institutions is in a state of flux. Tensions exist between the two dominant research orientations of research about and research for adaptation. In particular, the research community is challenged to develop processes for successfully executing transdisciplinary research for adaptation when academic institutions and researchers are largely structured around traditional, disciplinary expertise and funding models. One tool for helping to manage this tension is a third, more reflexive, orientation toward adaptation research that is emerging in the literature. Finally, this newmore » ‘research on adaptation research’ promises to help enhance understanding of the research enterprise itself and how it can become more adaptive.« less

  14. Intestinal mucosal atrophy and adaptation

    PubMed Central

    Shaw, Darcy; Gohil, Kartik; Basson, Marc D

    2012-01-01

    Mucosal adaptation is an essential process in gut homeostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical outcomes can be improved by manipulating the physiology of adaptation. This review will summarize current understanding of the basic science surrounding adaptation, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clinical outcomes. PMID:23197881

  15. Adaptive liquid crystal iris

    NASA Astrophysics Data System (ADS)

    Zhou, Zuowei; Ren, Hongwen; Nah, Changwoon

    2014-09-01

    We report an adaptive iris using a twisted nematic liquid crystal (TNLC) and a hole-patterned electrode. When an external voltage is applied to the TNLC, the directors of the LC near the edge of the hole are unwound first. Increasing the voltage can continuously unwind the LC toward the center. When the TNLC is sandwiched between two polarizers, it exhibits an iris-like character. Either a normal mode or a reverse mode can be obtained depending on the orientations of the transmission axes of the two polarizers. In contrast to liquid irises, the aperture of the LC iris can be closed completely. Moreover, it has the advantages of large variability of the aperture diameter, good stability, and low power consumption. Applications of the device for controlling the laser energy and correcting optical aberration are foreseeable.

  16. Computer adaptive testing.

    PubMed

    Gershon, Richard C

    2005-01-01

    The creation of item response theory (IRT) and Rasch models, inexpensive accessibility to high speed desktop computers, and the growth of the Internet, has led to the creation and growth of computerized adaptive testing or CAT. This form of assessment is applicable for both high stakes tests such as certification or licensure exams, as well as health related quality of life surveys. This article discusses the historical background of CAT including its many advantages over conventional (typically paper and pencil) alternatives. The process of CAT is then described including descriptions of the specific differences of using CAT based upon 1-, 2- and 3-parameter IRT and various Rasch models. Numerous specific topics describing CAT in practice are described including: initial item selection, content balancing, test difficulty, test length and stopping rules. The article concludes with the author's reflections regarding the future of CAT.

  17. Auto adaptative laser welding

    SciTech Connect

    Coste, F.; Fabbro, R.; Douay, D.; Sabatier, L.; Lacote, D.

    1996-12-31

    The weld preparation in a laboratory environment for laser welding concerning edge misalignments, edge or gap preparation is no longer valid for industrial configurations where these different parameters are not accurately controlled. Therefore in that case, the achievement of consistent qualities of processing, requires the use of sensors for seam tracking and gap recognition. The authors discuss here preliminary experiments involving the use of these elements in order to pilot a scanning head in view of strongly reducing the precision requirements for gap preparation. This set-up is the first step in the development of an auto-adaptative device for laser welding which will be composed of seam tracking and recognition sensors, scanning laser head and a filler wire device.

  18. Halophilic adaptation of enzymes.

    PubMed

    Madern, D; Ebel, C; Zaccai, G

    2000-04-01

    It is now clear that the understanding of halophilic adaptation at a molecular level requires a strategy of complementary experiments, combining molecular biology, biochemistry, and cellular approaches with physical chemistry and thermodynamics. In this review, after a discussion of the definition and composition of halophilic enzymes, the effects of salt on their activity, solubility, and stability are reviewed. We then describe how thermodynamic observations, such as parameters pertaining to solvent-protein interactions or enzyme-unfolding kinetics, depend strongly on solvent composition and reveal the important role played by water and ion binding to halophilic proteins. The three high-resolution crystal structures now available for halophilic proteins are analyzed in terms of haloadaptation, and finally cellular response to salt stress is discussed briefly.

  19. Environmentally Adaptive Reverberation Nulling

    DTIC Science & Technology

    2006-04-15

    Kim, H.C. Song, and W.A. Kuperman, “Adaptive time-reversal mirror,” J. Acoust. Soc. Am. 109(5): 1817-1825 (2001). [6] S. Kim, G. Edelmann , W.S...W.A. Kuperman, W.S. Hodgkiss, H.C. Song, G.F. Edelmann , and T. Akal, “Robust time reversal focusing in the ocean,” J. Acoust. Soc. Am. 114(1): 145-157...IEEE J. Oceanic Engr. 28(2): 246-249 (2003). [10] S. Kim, W.A. Kuperman, W.S. Hodgkiss, H.C. Spong, G.F. Edelmann , and T. Akal, “Echo-to

  20. Adaptive Immunity to Fungi

    PubMed Central

    Wüthrich, Marcel; Deepe, George S.; Klein, Bruce

    2013-01-01

    Only a handful of the more than 100,000 fungal species on our planet cause disease in humans, yet the number of life-threatening fungal infections in patients has recently skyrocketed as a result of advances in medical care that often suppress immunity intensely. This emerging crisis has created pressing needs to clarify immune defense mechanisms against fungi, with the ultimate goal of therapeutic applications. Herein, we describe recent insights in understanding the mammalian immune defenses deployed against pathogenic fungi. The review focuses on adaptive immune responses to the major medically important fungi and emphasizes how dendritic cells and subsets in various anatomic compartments respond to fungi, recognize their molecular patterns, and signal responses that nurture and shape the differentiation of T cell subsets and B cells. Also emphasized is how the latter deploy effector and regulatory mechanisms that eliminate these nasty invaders while also constraining collateral damage to vital tissue. PMID:22224780

  1. Research on Adaptive Antenna Techniques

    DTIC Science & Technology

    1977-01-01

    Jamming In an adaptive beamformer without obliteration of desired weak Input signals. However this method still has a major flaw in that the... Beamformer With Injected Noise (ABWIN). ^ Introduction to the Algorithm The basic idea behind the algorithm Is to feed Into an adaptive...the pilot signal of conventional adaptive beamformers I ]. The S* effect of a pilot signal constructed in this manner is described in a later section

  2. Link Dependent Adaptive Radio Simulation

    DTIC Science & Technology

    2014-06-01

    14. ABSTRACT This paper shows the optimized Link Dependent Adaptive Radio (LDAR) using the variable QAM OFDM modulation size which adapts to channel...bit error rate (BER), Orthogonal Frequency Division Multiplexing ( OFDM ) 16. SECURITY CLASSIFICATION OF: Unclassified 17. LIMITATION OF ABSTRACT...using the variable QAM OFDM modulation size which adapts to channel conditions. The LDAR enhanced performance is illustrated by use of a flight path

  3. Adaptive control of linearizable systems

    NASA Technical Reports Server (NTRS)

    Sastry, S. Shankar; Isidori, Alberto

    1989-01-01

    Initial results are reported regarding the adaptive control of minimum-phase nonlinear systems which are exactly input-output linearizable by state feedback. Parameter adaptation is used as a technique to make robust the exact cancellation of nonlinear terms, which is called for in the linearization technique. The application of the adaptive technique to control of robot manipulators is discussed. Only the continuous-time case is considered; extensions to the discrete-time and sampled-data cases are not obvious.

  4. Adaptive Mesh Refinement in CTH

    SciTech Connect

    Crawford, David

    1999-05-04

    This paper reports progress on implementing a new capability of adaptive mesh refinement into the Eulerian multimaterial shock- physics code CTH. The adaptivity is block-based with refinement and unrefinement occurring in an isotropic 2:1 manner. The code is designed to run on serial, multiprocessor and massive parallel platforms. An approximate factor of three in memory and performance improvements over comparable resolution non-adaptive calculations has-been demonstrated for a number of problems.

  5. Adaptive capacity and its assessment

    SciTech Connect

    Engle, Nathan L.

    2011-04-20

    This paper reviews the concept of adaptive capacity and various approaches to assessing it, particularly with respect to climate variability and change. I find that adaptive capacity is a relatively under-researched topic within the sustainability science and global change communities, particularly since it is uniquely positioned to improve linkages between vulnerability and resilience research. I identify opportunities for advancing the measurement and characterization of adaptive capacity by combining insights from both vulnerability and resilience frameworks, and I suggest several assessment approaches for possible future development that draw from both frameworks and focus on analyzing the governance, institutions, and management that have helped foster adaptive capacity in light of recent climatic events.

  6. Adaptive processing for LANDSAT data

    NASA Technical Reports Server (NTRS)

    Crane, R. B.; Reyer, J. F.

    1975-01-01

    Analytical and test results on the use of adaptive processing on LANDSAT data are presented. The Kalman filter was used as a framework to contain different adapting techniques. When LANDSAT MSS data were used all of the modifications made to the Kalman filter performed the functions for which they were designed. It was found that adaptive processing could provide compensation for incorrect signature means, within limits. However, if the data were such that poor classification accuracy would be obtained when the correct means were used, then adaptive processing would not improve the accuracy and might well lower it even further.

  7. [Adaptation of children to hospitalization].

    PubMed

    Kneist, W; Spangenberg, B

    1979-04-01

    Infants especially of about 1 to 4 years of age are opposed to an unknown environment and to unusual demands when they are admissed to hospital. Literature informes about some characteristic troubles during the first time of adaptation. In addition to those kinds of transitory adaptional difficulties, physical and mental retardation of development may appear when infants become long-time patients. The socalled psychic hospitalism has to be valued as a sign of underprotection and differs from adaptional troubles as a symptom of full strain. The survey shows adequate measures how physicians and nurses may deal with both of the problems in order to ease adaptation and to prevent psychic hospitalism.

  8. Adaptive Optics Communications Performance Analysis

    NASA Technical Reports Server (NTRS)

    Srinivasan, M.; Vilnrotter, V.; Troy, M.; Wilson, K.

    2004-01-01

    The performance improvement obtained through the use of adaptive optics for deep-space communications in the presence of atmospheric turbulence is analyzed. Using simulated focal-plane signal-intensity distributions, uncoded pulse-position modulation (PPM) bit-error probabilities are calculated assuming the use of an adaptive focal-plane detector array as well as an adaptively sized single detector. It is demonstrated that current practical adaptive optics systems can yield performance gains over an uncompensated system ranging from approximately 1 dB to 6 dB depending upon the PPM order and background radiation level.

  9. Adaptive Behaviour Assessment System: Indigenous Australian Adaptation Model (ABAS: IAAM)

    ERIC Educational Resources Information Center

    du Plessis, Santie

    2015-01-01

    The study objectives were to develop, trial and evaluate a cross-cultural adaptation of the Adaptive Behavior Assessment System-Second Edition Teacher Form (ABAS-II TF) ages 5-21 for use with Indigenous Australian students ages 5-14. This study introduced a multiphase mixed-method design with semi-structured and informal interviews, school…

  10. Adaptivity in ProPer: An Adaptive SCORM Compliant LMS

    ERIC Educational Resources Information Center

    Kazanidis, Ioannis; Satratzemi, Maya

    2009-01-01

    Adaptive Educational Hypermedia Systems provide personalized educational content to learners. However most of them do not support the functionality of Learning Management Systems (LMS) and the reusability of their courses is hard work. On the other hand some LMS support SCORM specifications but do not provide adaptive features. This article…

  11. Adaptivity in ProPer: An Adaptive SCORM Compliant LMS

    ERIC Educational Resources Information Center

    Kazanidis, Ioannis; Satratzemi, Maya

    2009-01-01

    Adaptive Educational Hypermedia Systems provide personalized educational content to learners. However most of them do not support the functionality of Learning Management Systems (LMS) and the reusability of their courses is hard work. On the other hand some LMS support SCORM specifications but do not provide adaptive features. This article…

  12. To Adapt or Not to Adapt: Navigating an Implementation Conundrum

    ERIC Educational Resources Information Center

    Leko, Melinda M.

    2015-01-01

    Maximizing the effectiveness of evidence-based practices (EBPs) requires an optimal balance of implementation fidelity and adaptation so EBPs fit local contexts and meet the individual learning needs of students with disabilities. The framework for classifying adaptations presented in this article can help educators make decisions about whether…

  13. To Adapt or Not to Adapt: Navigating an Implementation Conundrum

    ERIC Educational Resources Information Center

    Leko, Melinda M.

    2015-01-01

    Maximizing the effectiveness of evidence-based practices (EBPs) requires an optimal balance of implementation fidelity and adaptation so EBPs fit local contexts and meet the individual learning needs of students with disabilities. The framework for classifying adaptations presented in this article can help educators make decisions about whether…

  14. Smartphone adapters for digital photomicrography

    PubMed Central

    Roy, Somak; Pantanowitz, Liron; Amin, Milon; Seethala, Raja R.; Ishtiaque, Ahmed; Yousem, Samuel A.; Parwani, Anil V.; Cucoranu, Ioan; Hartman, Douglas J.

    2014-01-01

    Background: Photomicrographs in Anatomic Pathology provide a means of quickly sharing information from a glass slide for consultation, education, documentation and publication. While static image acquisition historically involved the use of a permanently mounted camera unit on a microscope, such cameras may be expensive, need to be connected to a computer, and often require proprietary software to acquire and process images. Another novel approach for capturing digital microscopic images is to use smartphones coupled with the eyepiece of a microscope. Recently, several smartphone adapters have emerged that allow users to attach mobile phones to the microscope. The aim of this study was to test the utility of these various smartphone adapters. Materials and Methods: We surveyed the market for adapters to attach smartphones to the ocular lens of a conventional light microscope. Three adapters (Magnifi, Skylight and Snapzoom) were tested. We assessed the designs of these adapters and their effectiveness at acquiring static microscopic digital images. Results: All adapters facilitated the acquisition of digital microscopic images with a smartphone. The optimal adapter was dependent on the type of phone used. The Magnifi adapters for iPhone were incompatible when using a protective case. The Snapzoom adapter was easiest to use with iPhones and other smartphones even with protective cases. Conclusions: Smartphone adapters are inexpensive and easy to use for acquiring digital microscopic images. However, they require some adjustment by the user in order to optimize focus and obtain good quality images. Smartphone microscope adapters provide an economically feasible method of acquiring and sharing digital pathology photomicrographs. PMID:25191623

  15. Adaptive Behavior: A Conceptual Analysis.

    ERIC Educational Resources Information Center

    Schmidt, Mary W.; Salvia, John

    1984-01-01

    The paper presents a model that examines the domain of adaptive behavior in terms of components (including physical needs, care of the environment, vocation, and understanding social conventions), and levels of performance (such as timing and degree of adaptation). (Author/CL)

  16. Adaptive Cartography and Geographical Education

    ERIC Educational Resources Information Center

    Konecny, Milan; Stanek, Karel

    2010-01-01

    The article focuses on adaptive cartography and its potential for geographical education. After briefly describing the wider context of adaptive cartography, it is suggested that this new cartographic approach establishes new demands and benefits for geographical education, especially in offering the possibility for broader individual…

  17. Adaptive arrays for satellite communications

    NASA Technical Reports Server (NTRS)

    Gupta, I. J.; Ksienski, A. A.

    1984-01-01

    The suppression of interfering signals in a satellite communication system was studied. Adaptive arrays are used to suppress interference at the reception site. It is required that the interference be suppressed to very low levels and a modified adaptive circuit is used which accomplishes the desired objective. Techniques for the modification of the transmit patterns to minimize interference with neighboring communication links are explored.

  18. Individual predictors of sensorimotor adaptability

    PubMed Central

    Seidler, Rachael D.; Mulavara, Ajitkumar P.; Bloomberg, Jacob J.; Peters, Brian T.

    2015-01-01

    There are large individual variations in strategies and rates of sensorimotor adaptation to spaceflight. This is seen in both the magnitude of performance disruptions when crewmembers are first exposed to microgravity, and in the rate of re-adaptation when they return to Earth’s gravitational environment. Understanding the sources of this variation can lead to a better understanding of the processes underlying adaptation, as well as provide insight into potential routes for facilitating performance of “slow adapters”. Here we review the literature on brain, behavioral, and genetic predictors of motor learning, recovery of motor function following neural insult, and sensorimotor adaptation. For example, recent studies have identified specific genetic polymorphisms that are associated with faster adaptation on manual joystick tasks and faster recovery of function following a stroke. Moreover, the extent of recruitment of specific brain regions during learning and adaptation has been shown to be predictive of the magnitude of subsequent learning. We close with suggestions for forward work aimed at identifying predictors of spaceflight adaptation success. Identification of “slow adapters” prior to spaceflight exposure would allow for more targeted preflight training and/or provision of booster training and adaptation adjuncts during spaceflight. PMID:26217197

  19. An Adaptive Course Generation Framework

    ERIC Educational Resources Information Center

    Li, Frederick W. B.; Lau, Rynson W. H.; Dharmendran, Parthiban

    2010-01-01

    Existing adaptive e-learning methods are supported by student (user) profiling for capturing student characteristics, and course structuring for organizing learning materials according to topics and levels of difficulties. Adaptive courses are then generated by extracting materials from the course structure to match the criteria specified in the…

  20. Interdisciplinarity in Adapted Physical Activity

    ERIC Educational Resources Information Center

    Bouffard, Marcel; Spencer-Cavaliere, Nancy

    2016-01-01

    It is commonly accepted that inquiry in adapted physical activity involves the use of different disciplines to address questions. It is often advanced today that complex problems of the kind frequently encountered in adapted physical activity require a combination of disciplines for their solution. At the present time, individual research…

  1. Adaptive Cartography and Geographical Education

    ERIC Educational Resources Information Center

    Konecny, Milan; Stanek, Karel

    2010-01-01

    The article focuses on adaptive cartography and its potential for geographical education. After briefly describing the wider context of adaptive cartography, it is suggested that this new cartographic approach establishes new demands and benefits for geographical education, especially in offering the possibility for broader individual…

  2. Adaptive Learning and Risk Taking

    ERIC Educational Resources Information Center

    Denrell, Jerker

    2007-01-01

    Humans and animals learn from experience by reducing the probability of sampling alternatives with poor past outcomes. Using simulations, J. G. March (1996) illustrated how such adaptive sampling could lead to risk-averse as well as risk-seeking behavior. In this article, the author develops a formal theory of how adaptive sampling influences risk…

  3. Interdisciplinarity in Adapted Physical Activity

    ERIC Educational Resources Information Center

    Bouffard, Marcel; Spencer-Cavaliere, Nancy

    2016-01-01

    It is commonly accepted that inquiry in adapted physical activity involves the use of different disciplines to address questions. It is often advanced today that complex problems of the kind frequently encountered in adapted physical activity require a combination of disciplines for their solution. At the present time, individual research…

  4. An Adaptive Course Generation Framework

    ERIC Educational Resources Information Center

    Li, Frederick W. B.; Lau, Rynson W. H.; Dharmendran, Parthiban

    2010-01-01

    Existing adaptive e-learning methods are supported by student (user) profiling for capturing student characteristics, and course structuring for organizing learning materials according to topics and levels of difficulties. Adaptive courses are then generated by extracting materials from the course structure to match the criteria specified in the…

  5. Disciplinary Literacy: "Adapt" Not Adopt

    ERIC Educational Resources Information Center

    Gillis, Victoria

    2014-01-01

    This article argues that every teacher is not a teacher of literacy, but instead posits that teachers in content areas must adapt literacy strategies to the content being taught and to the context in which that teaching occurs. Examples of adaptations of a literacy strategy for use in English/language arts, mathematics, science, and social studies…

  6. Cultural Adaptation in Outdoor Programming

    ERIC Educational Resources Information Center

    Fabrizio, Sheila M.; Neill, James

    2005-01-01

    Outdoor programs often intentionally provide a different culture and the challenge of working out how to adapt. Failure to adapt, however, can cause symptoms of culture shock, including homesickness, negative personal behavior, and interpersonal conflict. This article links cross-cultural and outdoor programming literature and provides case…

  7. Adaptation Research in Rehabilitation Counseling

    ERIC Educational Resources Information Center

    Parker, Randall M.

    2007-01-01

    This paper reviews current research concerning psychosocial adaptation to chronic illness and disability and presents recommendations for future development of theories in this area. First, those who craft or adapt theories must use nondisabling, respectful, and empowering language. Rehabilitation professionals must avoid terms that connote…

  8. Adaptive Learning and Risk Taking

    ERIC Educational Resources Information Center

    Denrell, Jerker

    2007-01-01

    Humans and animals learn from experience by reducing the probability of sampling alternatives with poor past outcomes. Using simulations, J. G. March (1996) illustrated how such adaptive sampling could lead to risk-averse as well as risk-seeking behavior. In this article, the author develops a formal theory of how adaptive sampling influences risk…

  9. Codon Adaptation of Plastid Genes

    PubMed Central

    Suzuki, Haruo; Morton, Brian R.

    2016-01-01

    Codon adaptation is codon usage bias that results from selective pressure to increase the translation efficiency of a gene. Codon adaptation has been studied across a wide range of genomes and some early analyses of plastids have shown evidence for codon adaptation in a limited set of highly expressed plastid genes. Here we study codon usage bias across all fully sequenced plastid genomes which includes representatives of the Rhodophyta, Alveolata, Cryptophyta, Euglenozoa, Glaucocystophyceae, Rhizaria, Stramenopiles and numerous lineages within the Viridiplantae, including Chlorophyta and Embryophyta. We show evidence that codon adaptation occurs in all genomes except for two, Theileria parva and Heicosporidium sp., both of which have highly reduced gene contents and no photosynthesis genes. We also show evidence that selection for codon adaptation increases the representation of the same set of codons, which we refer to as the adaptive codons, across this wide range of taxa, which is probably due to common features descended from the initial endosymbiont. We use various measures to estimate the relative strength of selection in the different lineages and show that it appears to be fairly strong in certain Stramenopiles and Chlorophyta lineages but relatively weak in many members of the Rhodophyta, Euglenozoa and Embryophyta. Given these results we propose that codon adaptation in plastids is widespread and displays the same general features as adaptation in eubacterial genomes. PMID:27196606

  10. Adaptive Assessments Using Open Specifications

    ERIC Educational Resources Information Center

    Leon, Hector Barbosa; Garcia-Penalvo, Francisco J.; Rodriguez-Conde, Maria Jose; Morales, Erla M.; de Pablos, Patricia Ordonez

    2012-01-01

    Evaluation is a key element in formal education processes; it must be constructed in a way that the item questions within help students understand by adapting them to the learning style as well. The focus of the present research work specifically in the convenience to adapt an associated multimedia material in each single question besides the…

  11. Adaptive multibeam antenna array

    NASA Astrophysics Data System (ADS)

    Novikov, V. I.

    1984-01-01

    An adaptive multibeam antenna array is considered which will enhance the advantages of a plain one. By providing simultaneous reception of signals from different directions and their sequential processing. The optimization of the array control for maximum interference suppression in the radiation pattern is emphasized. The optimum control is sought with respect to the signal-to-interference power ratio as a genaralized criterion. Sampled useful signals and transmission coefficients are found to be complex-conjugate quantities, assuming compatible formation of beams, so that synphasal equiamplitude addition of signals from all array element is attainable by unique settings of the weight factors. Calculations are simplified by letting the useful signal power in the 1-th beam be approximately equal to the k-th weight factor, before optimizing the weight vector for maximum signal-to-interference ratio. A narrowband interference described by power P and vector V of signal distribution over the array is considered as an example, to demonstrate the algorithm of synthesis. The algorithm, using the Butler matrix, was executed experimentally on a computer for a linear equidistant antenna array of 32 elements with compatible formation of beams.

  12. Adapt or die?

    PubMed

    Visser, S S; Nel, A H

    1996-12-01

    The worldwide economic recession and the concomitant limited stock of finances have had an influence on the available money of every household and have also inhibited the improvement of socio-economic conditions and medicine. The Reconstruction and Development Programme (RDP) has the objective of improving the living conditions of the people with regard to housing, education, training and health care. The latter seems to be a major problem which has to be addressed with the emphasis on the preventive and promotional aspects of health care. A comprehensive health care system did not come into being property in the past because of the maldistribution of health care services, personnel and differences in culture and health care beliefs and values. The question that now arises, is how to render a quality health care service within the constraints of inadequate financing and resources. A comprehensive literature study has been done with reference to quality health care and financing followed by a survey of existing health services and finances. Recommendations are made about minimum requirements to be accepted if one were to adapt rather than die in terms of the provision of healthcare: the decentralization and rationalization of the administration of health care, the stress on and realization of effective and efficient primary health care, the acceptance of participative management in health providing organizations, the provision of financial management training for health care managers and the application of management accounting principles for the improvement of the efficiency and effectiveness of management.

  13. Adaptive synthetic vision

    NASA Astrophysics Data System (ADS)

    Julier, Simon J.; Brown, Dennis; Livingston, Mark A.; Thomas, Justin

    2006-05-01

    Through their ability to safely collect video and imagery from remote and potentially dangerous locations, UAVs have already transformed the battlespace. The effectiveness of this information can be greatly enhanced through synthetic vision. Given knowledge of the extrinsic and intrinsic parameters of the camera, synthetic vision superimposes spatially-registered computer graphics over the video feed from the UAV. This technique can be used to show many types of data such as landmarks, air corridors, and the locations of friendly and enemy forces. However, the effectiveness of a synthetic vision system strongly depends on the accuracy of the registration - if the graphics are poorly aligned with the real world they can be confusing, annoying, and even misleading. In this paper, we describe an adaptive approach to synthetic vision that modifies the way in which information is displayed depending upon the registration error. We describe an integrated software architecture that has two main components. The first component automatically calculates registration error based on information about the uncertainty in the camera parameters. The second component uses this information to modify, aggregate, and label annotations to make their interpretation as clear as possible. We demonstrate the use of this approach on some sample datasets.

  14. Architecture Adaptive Computing Environment

    NASA Technical Reports Server (NTRS)

    Dorband, John E.

    2006-01-01

    Architecture Adaptive Computing Environment (aCe) is a software system that includes a language, compiler, and run-time library for parallel computing. aCe was developed to enable programmers to write programs, more easily than was previously possible, for a variety of parallel computing architectures. Heretofore, it has been perceived to be difficult to write parallel programs for parallel computers and more difficult to port the programs to different parallel computing architectures. In contrast, aCe is supportable on all high-performance computing architectures. Currently, it is supported on LINUX clusters. aCe uses parallel programming constructs that facilitate writing of parallel programs. Such constructs were used in single-instruction/multiple-data (SIMD) programming languages of the 1980s, including Parallel Pascal, Parallel Forth, C*, *LISP, and MasPar MPL. In aCe, these constructs are extended and implemented for both SIMD and multiple- instruction/multiple-data (MIMD) architectures. Two new constructs incorporated in aCe are those of (1) scalar and virtual variables and (2) pre-computed paths. The scalar-and-virtual-variables construct increases flexibility in optimizing memory utilization in various architectures. The pre-computed-paths construct enables the compiler to pre-compute part of a communication operation once, rather than computing it every time the communication operation is performed.

  15. Fidelity of adaptive phototaxis.

    PubMed

    Drescher, Knut; Goldstein, Raymond E; Tuval, Idan

    2010-06-22

    Along the evolutionary path from single cells to multicellular organisms with a central nervous system are species of intermediate complexity that move in ways suggesting high-level coordination, yet have none. Instead, organisms of this type possess many autonomous cells endowed with programs that have evolved to achieve concerted responses to environmental stimuli. Here experiment and theory are used to develop a quantitative understanding of how cells of such organisms coordinate to achieve phototaxis, by using the colonial alga Volvox carteri as a model. It is shown that the surface somatic cells act as individuals but are orchestrated by their relative position in the spherical extracellular matrix and their common photoresponse function to achieve colony-level coordination. Analysis of models that range from the minimal to the biologically faithful shows that, because the flagellar beating displays an adaptive down-regulation in response to light, the colony needs to spin around its swimming direction and that the response kinetics and natural spinning frequency of the colony appear to be mutually tuned to give the maximum photoresponse. These models further predict that the phototactic ability decreases dramatically when the colony does not spin at its natural frequency, a result confirmed by phototaxis assays in which colony rotation was slowed by increasing the fluid viscosity.

  16. Adaptive thermogenesis in humans

    PubMed Central

    Rosenbaum, Michael; Leibel, Rudolph L.

    2013-01-01

    The increasing prevalence of obesity and its co-morbidities reflects the interaction of genes that favor the storage of excess calories as fat with an environment that provides ad libitum availability of calorically dense foods and encourages an increasingly sedentary lifestyle. While weight reduction is difficult in and of itself, anyone who has every lost weight will confirm that it is much harder to keep the weight off once it has been lost. The over 80% recidivism rate to pre-weight loss levels of body fatness after otherwise successful weight loss is due to the coordinate actions of metabolic, behavioral, neuroendocrine, and autonomic responses designed to maintain body energy stores (fat) at a CNS- defined “ideal”. This “adaptive thermogenesis” creates the ideal situation for weight regain and is operant in both lean and obese individuals attempting to sustain reduced body weights. Much of this opposition to sustained weight loss is mediated by the adipocyte-derived hormone “leptin”. The multiplicity of systems regulating energy stores and opposing the maintenance of a reduced body weight illustrate that body energy stores in general and obesity in particular are actively “defended” by interlocking bioenergetic and neurobiological physiologies. Important inferences can be drawn for therapeutic strategies by recognizing obesity as a disease in which the human body actively opposes the “cure” over long periods of time beyond the initial resolution of symptomatology. PMID:20935667

  17. Fidelity of adaptive phototaxis

    PubMed Central

    Drescher, Knut; Goldstein, Raymond E.; Tuval, Idan

    2010-01-01

    Along the evolutionary path from single cells to multicellular organisms with a central nervous system are species of intermediate complexity that move in ways suggesting high-level coordination, yet have none. Instead, organisms of this type possess many autonomous cells endowed with programs that have evolved to achieve concerted responses to environmental stimuli. Here experiment and theory are used to develop a quantitative understanding of how cells of such organisms coordinate to achieve phototaxis, by using the colonial alga Volvox carteri as a model. It is shown that the surface somatic cells act as individuals but are orchestrated by their relative position in the spherical extracellular matrix and their common photoresponse function to achieve colony-level coordination. Analysis of models that range from the minimal to the biologically faithful shows that, because the flagellar beating displays an adaptive down-regulation in response to light, the colony needs to spin around its swimming direction and that the response kinetics and natural spinning frequency of the colony appear to be mutually tuned to give the maximum photoresponse. These models further predict that the phototactic ability decreases dramatically when the colony does not spin at its natural frequency, a result confirmed by phototaxis assays in which colony rotation was slowed by increasing the fluid viscosity. PMID:20534560

  18. Atmospheric and adaptive optics

    NASA Astrophysics Data System (ADS)

    Hickson, Paul

    2014-11-01

    Atmospheric optics is the study of optical effects induced by the atmosphere on light propagating from distant sources. Of particular concern to astronomers is atmospheric turbulence, which limits the performance of ground-based telescopes. The past two decades have seen remarkable growth in the capabilities and performance of adaptive optics (AO) systems. These opto-mechanical systems actively compensate for the blurring effect of the Earth's turbulent atmosphere. By sensing, and correcting, wavefront distortion introduced by atmospheric index-of-refraction variations, AO systems can produce images with resolution approaching the diffraction limit of the telescope at near-infrared wavelengths. This review highlights the physical processes and fundamental relations of atmospheric optics that are most relevant to astronomy, and discusses the techniques used to characterize atmospheric turbulence. The fundamentals of AO are then introduced and the many types of advanced AO systems that have been developed are described. The principles of each are outlined, and the performance and limitations are examined. Aspects of photometric and astrometric measurements of AO-corrected images are considered. The paper concludes with a discussion of some of the challenges related to current and future AO systems, particularly those that will equip the next generation of large, ground-based optical and infrared telescopes.

  19. Adaptive Immunity to Fungi

    PubMed Central

    Verma, Akash; Wüthrich, Marcel; Deepe, George; Klein, Bruce

    2015-01-01

    Life-threatening fungal infections have risen sharply in recent years, owing to the advances and intensity of medical care that may blunt immunity in patients. This emerging crisis has created the growing need to clarify immune defense mechanisms against fungi with the ultimate goal of therapeutic intervention. We describe recent insights in understanding the mammalian immune defenses that are deployed against pathogenic fungi. We focus on adaptive immunity to the major medically important fungi and emphasize three elements that coordinate the response: (1) dendritic cells and subsets that are mobilized against fungi in various anatomical compartments; (2) fungal molecular patterns and their corresponding receptors that signal responses and shape the differentiation of T-cell subsets and B cells; and, ultimately (3) the effector and regulatory mechanisms that eliminate these invaders while constraining collateral damage to vital tissue. These insights create a foundation for the development of new, immune-based strategies for prevention or enhanced clearance of systemic fungal diseases. PMID:25377140

  20. Adaptive vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Behrens, Sam; Ward, John; Davidson, Josh

    2007-04-01

    By scavenging energy from their local environment, portable electronic devices such as mobile phones, radios and wireless sensors can achieve greater run-times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy, through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilise a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaption to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27 - 34%. However, simulations of a more electro-mechanical efficient and lightly damped transducer show conversion efficiencies in excess of 80%.

  1. Statistical Physics of Adaptation

    NASA Astrophysics Data System (ADS)

    Perunov, Nikolay; Marsland, Robert A.; England, Jeremy L.

    2016-04-01

    Whether by virtue of being prepared in a slowly relaxing, high-free energy initial condition, or because they are constantly dissipating energy absorbed from a strong external drive, many systems subject to thermal fluctuations are not expected to behave in the way they would at thermal equilibrium. Rather, the probability of finding such a system in a given microscopic arrangement may deviate strongly from the Boltzmann distribution, raising the question of whether thermodynamics still has anything to tell us about which arrangements are the most likely to be observed. In this work, we build on past results governing nonequilibrium thermodynamics and define a generalized Helmholtz free energy that exactly delineates the various factors that quantitatively contribute to the relative probabilities of different outcomes in far-from-equilibrium stochastic dynamics. By applying this expression to the analysis of two examples—namely, a particle hopping in an oscillating energy landscape and a population composed of two types of exponentially growing self-replicators—we illustrate a simple relationship between outcome-likelihood and dissipative history. In closing, we discuss the possible relevance of such a thermodynamic principle for our understanding of self-organization in complex systems, paying particular attention to a possible analogy to the way evolutionary adaptations emerge in living things.

  2. Adapting traditional healing practices.

    PubMed

    Weiser, J

    1999-01-01

    The Aboriginal people in Canada have been noted to have low self-esteem, subsequently increasing their risk of HIV. To this effect, two traditional healing practices are being used to help these people avoid HIV infection, and to live more healthily and positively if they are infected. The first method is the Medicine Wheel, which is a traditional model used to represent the complex interrelationship among all living things and show how their immune system is physically affected by their emotions and worries. Many Aboriginal AIDS Organizations, counselors and others are now using this AIDS teaching Wheel model. Meanwhile, the second method is the Sharing Circles, which provide an environment where people feel safe to talk about HIV and give participants a sense of support and a means for expression without stigma or judgement. As a result, many people who attend HIV circles begin to take better care of themselves and of others. Overall, it is emphasized that these traditional healing practices can be effectively adapted for use in HIV counseling and education.

  3. Adaptive Composite Map Projections.

    PubMed

    Jenny, B

    2012-12-01

    All major web mapping services use the web Mercator projection. This is a poor choice for maps of the entire globe or areas of the size of continents or larger countries because the Mercator projection shows medium and higher latitudes with extreme areal distortion and provides an erroneous impression of distances and relative areas. The web Mercator projection is also not able to show the entire globe, as polar latitudes cannot be mapped. When selecting an alternative projection for information visualization, rivaling factors have to be taken into account, such as map scale, the geographic area shown, the map's height-to-width ratio, and the type of cartographic visualization. It is impossible for a single map projection to meet the requirements for all these factors. The proposed composite map projection combines several projections that are recommended in cartographic literature and seamlessly morphs map space as the user changes map scale or the geographic region displayed. The composite projection adapts the map's geometry to scale, to the map's height-to-width ratio, and to the central latitude of the displayed area by replacing projections and adjusting their parameters. The composite projection shows the entire globe including poles; it portrays continents or larger countries with less distortion (optionally without areal distortion); and it can morph to the web Mercator projection for maps showing small regions.

  4. Reward modulates adaptations to conflict.

    PubMed

    Braem, Senne; Verguts, Tom; Roggeman, Chantal; Notebaert, Wim

    2012-11-01

    Both cognitive conflict (e.g. Verguts & Notebaert, 2009) and reward signals (e.g. Waszak & Pholulamdeth, 2009) have been proposed to enhance task-relevant associations. Bringing these two notions together, we predicted that reward modulates conflict-based sequential adaptations in cognitive control. This was tested combining either a single flanker task (Experiment 1) or a task-switch paradigm (Experiment 2) with performance-related rewards. Both experiments confirmed that adaptations after conflict were modulated by reward. In the flanker task, this resulted in increased conflict adaptation after rewarded trials. In the task-switching experiment, reward increased the conflict-modulated switch cost. Interestingly, both adaptations to conflict disappeared after no-reward trials. Moreover, individual differences in participants' sensitivity to reward predicted these reward modulations of trial-to-trial adaptations. These findings shed new light on the exact role of cognitive conflict in shaping subsequent behavior.

  5. Parallel Adaptive Mesh Refinement

    SciTech Connect

    Diachin, L; Hornung, R; Plassmann, P; WIssink, A

    2005-03-04

    As large-scale, parallel computers have become more widely available and numerical models and algorithms have advanced, the range of physical phenomena that can be simulated has expanded dramatically. Many important science and engineering problems exhibit solutions with localized behavior where highly-detailed salient features or large gradients appear in certain regions which are separated by much larger regions where the solution is smooth. Examples include chemically-reacting flows with radiative heat transfer, high Reynolds number flows interacting with solid objects, and combustion problems where the flame front is essentially a two-dimensional sheet occupying a small part of a three-dimensional domain. Modeling such problems numerically requires approximating the governing partial differential equations on a discrete domain, or grid. Grid spacing is an important factor in determining the accuracy and cost of a computation. A fine grid may be needed to resolve key local features while a much coarser grid may suffice elsewhere. Employing a fine grid everywhere may be inefficient at best and, at worst, may make an adequately resolved simulation impractical. Moreover, the location and resolution of fine grid required for an accurate solution is a dynamic property of a problem's transient features and may not be known a priori. Adaptive mesh refinement (AMR) is a technique that can be used with both structured and unstructured meshes to adjust local grid spacing dynamically to capture solution features with an appropriate degree of resolution. Thus, computational resources can be focused where and when they are needed most to efficiently achieve an accurate solution without incurring the cost of a globally-fine grid. Figure 1.1 shows two example computations using AMR; on the left is a structured mesh calculation of a impulsively-sheared contact surface and on the right is the fuselage and volume discretization of an RAH-66 Comanche helicopter [35]. Note the

  6. Adaptive Phase Delay Generator

    NASA Technical Reports Server (NTRS)

    Greer, Lawrence

    2013-01-01

    There are several experimental setups involving rotating machinery that require some form of synchronization. The adaptive phase delay generator (APDG) the Bencic-1000 is a flexible instrument that allows the user to generate pulses synchronized to the rising edge of a tachometer signal from any piece of rotating machinery. These synchronized pulses can vary by the delay angle, pulse width, number of pulses per period, number of skipped pulses, and total number of pulses. Due to the design of the pulse generator, any and all of these parameters can be changed independently, yielding an unparalleled level of versatility. There are two user interfaces to the APDG. The first is a LabVIEW program that has the advantage of displaying all of the pulse parameters and input signal data within one neatly organized window on the PC monitor. Furthermore, the LabVIEW interface plots the rpm of the two input signal channels in real time. The second user interface is a handheld portable device that goes anywhere a computer is not accessible. It consists of a liquid-crystal display and keypad, which enable the user to control the unit by scrolling through a host of command menus and parameter listings. The APDG combines all of the desired synchronization control into one unit. The experimenter can adjust the delay, pulse width, pulse count, number of skipped pulses, and produce a specified number of pulses per revolution. Each of these parameters can be changed independently, providing an unparalleled level of versatility when synchronizing hardware to a host of rotating machinery. The APDG allows experimenters to set up quickly and generate a host of synchronizing configurations using a simple user interface, which hopefully leads to faster results.

  7. Adaptive multiconfigurational wave functions.

    PubMed

    Evangelista, Francesco A

    2014-03-28

    A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff Λ. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than Λ. The resulting Λ-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (Λ+SD-CI), which is based on a small Λ-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build Λ-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The Λ-CI and Λ+SD-CI approaches are used to compute the dissociation curve of N2 and the potential energy curves for the first three singlet states of C2. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the Λ-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu2O2(2+) core, illustrates an alternative use of the Λ-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

  8. Adaptive multiconfigurational wave functions

    SciTech Connect

    Evangelista, Francesco A.

    2014-03-28

    A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff Λ. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than Λ. The resulting Λ-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (Λ+SD-CI), which is based on a small Λ-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build Λ-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The Λ-CI and Λ+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the Λ-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the Λ-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

  9. Adaptation of naturally paced saccades

    PubMed Central

    Blangero, Annabelle; Herman, James P.; Wallman, Josh; Harwood, Mark R.

    2014-01-01

    In the natural environment, humans make saccades almost continuously. In many eye movement experiments, however, observers are required to fixate for unnaturally long periods of time. The resulting long and monotonous experimental sessions can become especially problematic when collecting data in a clinical setting, where time can be scarce and subjects easily fatigued. With this in mind, we tested whether the well-studied motor learning process of saccade adaptation could be induced with a dramatically shortened intertrial interval. Observers made saccades to targets that stepped left or right either ∼250 ms or ∼1,600 ms after the saccade landed. In experiment I, we tested baseline saccade parameters to four different target amplitudes (5°, 10°, 15°, and 20°) in the two timing settings. In experiments II and III, we adapted 10° saccades via 2° intrasaccadic steps either backwards or forwards, respectively. Seven subjects performed eight separate adaptation sessions (2 intertrial timings × 2 adaptation direction × 2 session trial lengths). Adaptation proceeded remarkably similarly in both timing conditions across the multiple sessions. In the faster-paced sessions, robust adaptation was achieved in under 2 min, demonstrating the efficacy of our approach to streamlining saccade adaptation experiments. Although saccade amplitudes were similar between conditions, the faster-paced condition unexpectedly resulted in significantly higher peak velocities in all subjects. This surprising finding demonstrates that the stereotyped “main sequence” relationship between saccade amplitude and peak velocity is not as fixed as originally thought. PMID:24623511

  10. Prism adaptation by mental practice.

    PubMed

    Michel, Carine; Gaveau, Jérémie; Pozzo, Thierry; Papaxanthis, Charalambos

    2013-09-01

    The prediction of our actions and their interaction with the external environment is critical for sensorimotor adaptation. For instance, during prism exposure, which deviates laterally our visual field, we progressively correct movement errors by combining sensory feedback with forward model sensory predictions. However, very often we project our actions to the external environment without physically interacting with it (e.g., mental actions). An intriguing question is whether adaptation will occur if we imagine, instead of executing, an arm movement while wearing prisms. Here, we investigated prism adaptation during mental actions. In the first experiment, participants (n = 54) performed arm pointing movements before and after exposure to the optical device. They were equally divided into six groups according to prism exposure: Prisms-Active, Prisms-Imagery, Prisms-Stationary, Prisms-Stationary-Attention, No Conflict-Prisms-Imagery, No Prisms-Imagery. Adaptation, measured by the difference in pointing errors between pre-test and post-test, occurred only in Prisms-Active and Prisms-Imagery conditions. The second experiment confirmed the results of the first experiment and further showed that sensorimotor adaptation was mainly due to proprioceptive realignment in both Prisms-Active (n = 10) and Prisms-Imagery (n = 10) groups. In both experiments adaptation was greater following actual than imagined pointing movements. The present results are the first demonstration of prism adaptation by mental practice under prism exposure and they are discussed in terms of internal forward models and sensorimotor plasticity.

  11. Adaptive Immunity Against Staphylococcus aureus.

    PubMed

    Karauzum, Hatice; Datta, Sandip K

    2016-02-27

    A complex interplay between host and bacterial factors allows Staphylococcus aureus to occupy its niche as a human commensal and a major human pathogen. The role of neutrophils as a critical component of the innate immune response against S. aureus, particularly for control of systemic infection, has been established in both animal models and in humans with acquired and congenital neutrophil dysfunction. The role of the adaptive immune system is less clear. Although deficiencies in adaptive immunity do not result in the marked susceptibility to S. aureus infection that neutrophil dysfunction imparts, emerging evidence suggests both T cell- and B cell-mediated adaptive immunity can influence host susceptibility and control of S. aureus. The contribution of adaptive immunity depends on the context and site of infection and can be either beneficial or detrimental to the host. Furthermore, S. aureus has evolved mechanisms to manipulate adaptive immune responses to its advantage. In this chapter, we will review the evidence for the role of adaptive immunity during S. aureus infections. Further elucidation of this role will be important to understand how it influences susceptibility to infection and to appropriately design vaccines that elicit adaptive immune responses to protect against subsequent infections.

  12. Binocular measurements of chromatic adaptation.

    PubMed

    Troost, J M; Wei, L; de Weert, C M

    1992-10-01

    In this paper we present asymmetric matching data that were obtained with a binocular presentation method. Our main motivation was the question whether chromatic adaptation, one of the important mechanisms that contribute to colour constancy, has evolved towards a better performance in the range of colours that are present in the natural image. For the eye adapted to a bluish illuminant for example the presence of an object with a deep yellow colour is very unlikely. So, it was expected that the colour difference between adapting light and target has an influence on the extent of chromatic adaptation. It was found that the colour shift in the observers' matches that can be attributed to chromatic adaptation indeed has a maximum. The location of the maximum, however, was unexpected, i.e. colour differences between target and adapting light that lie around 0.05 u'v'-chromaticity units. Additionally, several models for chromatic adaptation were fitted to our data. It was found that, except for the simple von Kries model, Retinex Theory and difference contrast, a number of models gave good predictions for the L-wave and M-wave fundamental systems, but that predictions for the S-wave system were less accurate.

  13. Adaptation Forestry in Minnesota's Northwoods

    NASA Astrophysics Data System (ADS)

    Cornett, M.; White, M.; Etterson, J.; Kavajecz, L.; Mead, J.; Handler, S.; Swanston, C.; Hall, K.

    2014-12-01

    Forest restoration and management goals are shifting in northern Minnesota in light of new information on climate trends. Adaptation forestry encompasses a combination of practices designed to favor native populations and species likely to persist under warmer, drier conditions. The overarching project goal is to increase the adaptive capacity of northern forests such that they continue to sustain a variety of services, including carbon sequestration, fiber production, watershed protection, and wildlife habitat. We are currently testing the feasibility and efficacy of adaptation forestry in the northern Great Lakes region in three common forest types: Boreal-Mixed, Pine, and Hardwoods. 12 sites (2,000 acres total) recently subjected to a range of structural treatments (gap creation, shelterwood, and clear-cut with reserves) were coupled with "adaptation plantings" of species that are likely to thrive under changed climate conditions (e.g., red oak, bur oak, white pine). Seedlings, ~110,000 total, originated from two source locations, one that reflects current adaptation to the climate of northern Minnesota and another from a more southern source in central Minnesota. To date, we have assessed results from two growing seasons by tracking survival, growth and phenological characteristics of planted seedlings. This project is a first step in determining whether adaptation management can be used as a tool to help northern forests transition to an uncertain future. Cooperation with state, federal, and academic partners may ultimately influence the adaptive capacity across millions of acres in the Great Lakes region.

  14. Countermeasures to Enhance Sensorimotor Adaptability

    NASA Technical Reports Server (NTRS)

    Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. C.; Miller, C. A.; Cohen, H. S.

    2011-01-01

    During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The goal of our current project is to develop a sensorimotor adaptability (SA) training program to facilitate rapid adaptation to novel gravitational environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene that provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. We have conducted a series of studies that have shown: Training using a combination of modified visual flow and support surface motion during treadmill walking enhances locomotor adaptability to a novel sensorimotor environment. Trained individuals become more proficient at performing multiple competing tasks while walking during adaptation to novel discordant sensorimotor conditions. Trained subjects can retain their increased level of adaptability over a six months period. SA training is effective in producing increased adaptability in a more complex over-ground ambulatory task on an obstacle course. This confirms that for a complex task like walking, treadmill training contains enough of the critical features of overground walking to be an effective training modality. The structure of individual training sessions can be optimized to promote fast/strategic motor learning. Training sessions that each contain short-duration exposures to multiple perturbation stimuli allows subjects to acquire a greater ability to rapidly reorganize appropriate response strategies when encountering a novel sensory environment. Individual sensory biases (i.e. increased visual dependency) can predict adaptive responses to novel sensory environments suggesting that customized training prescriptions can be developed to enhance

  15. Coastal adaptation with ecological engineering

    NASA Astrophysics Data System (ADS)

    Cheong, So-Min; Silliman, Brian; Wong, Poh Poh; van Wesenbeeck, Bregje; Kim, Choong-Ki; Guannel, Greg

    2013-09-01

    The use of combined approaches to coastal adaptation in lieu of a single strategy, such as sea-wall construction, allows for better preparation for a highly uncertain and dynamic coastal environment. Although general principles such as mainstreaming and no- or low-regret options exist to guide coastal adaptation and provide the framework in which combined approaches operate, few have examined the interactions, synergistic effects and benefits of combined approaches to adaptation. This Perspective provides three examples of ecological engineering -- marshes, mangroves and oyster reefs -- and illustrates how the combination of ecology and engineering works.

  16. Visual adaptation dominates bimodal visual-motor action adaptation

    PubMed Central

    de la Rosa, Stephan; Ferstl, Ylva; Bülthoff, Heinrich H.

    2016-01-01

    A long standing debate revolves around the question whether visual action recognition primarily relies on visual or motor action information. Previous studies mainly examined the contribution of either visual or motor information to action recognition. Yet, the interaction of visual and motor action information is particularly important for understanding action recognition in social interactions, where humans often observe and execute actions at the same time. Here, we behaviourally examined the interaction of visual and motor action recognition processes when participants simultaneously observe and execute actions. We took advantage of behavioural action adaptation effects to investigate behavioural correlates of neural action recognition mechanisms. In line with previous results, we find that prolonged visual exposure (visual adaptation) and prolonged execution of the same action with closed eyes (non-visual motor adaptation) influence action recognition. However, when participants simultaneously adapted visually and motorically – akin to simultaneous execution and observation of actions in social interactions - adaptation effects were only modulated by visual but not motor adaptation. Action recognition, therefore, relies primarily on vision-based action recognition mechanisms in situations that require simultaneous action observation and execution, such as social interactions. The results suggest caution when associating social behaviour in social interactions with motor based information. PMID:27029781

  17. The vulnerability of threatened species: adaptive capability and adaptation opportunity.

    PubMed

    Berry, Pam; Ogawa-Onishi, Yuko; McVey, Andrew

    2013-07-01

    Global targets to halt the loss of biodiversity have not been met, and there is now an additional Aichi target for preventing the extinction of known threatened species and improving their conservation status. Climate change increasingly needs to be factored in to these, and thus there is a need to identify the extent to which it could increase species vulnerability. This paper uses the exposure, sensitivity, and adaptive capacity framework to assess the vulnerability of a selection of WWF global priority large mammals and marine species to climate change. However, it divides adaptive capacity into adaptive capability and adaptation opportunity, in order to identify whether adaptation is more constrained by the biology of the species or by its environmental setting. Lack of evidence makes it difficult to apply the framework consistently across the species, but it was found that, particularly for the terrestrial mammals, adaptation opportunities seems to be the greater constraint. This framework and analysis could be used by conservationists and those wishing to enhance the resilience of species to climate change.

  18. The Vulnerability of Threatened Species: Adaptive Capability and Adaptation Opportunity

    PubMed Central

    Berry, Pam; Ogawa-Onishi, Yuko; McVey, Andrew

    2013-01-01

    Global targets to halt the loss of biodiversity have not been met, and there is now an additional Aichi target for preventing the extinction of known threatened species and improving their conservation status. Climate change increasingly needs to be factored in to these, and thus there is a need to identify the extent to which it could increase species vulnerability. This paper uses the exposure, sensitivity, and adaptive capacity framework to assess the vulnerability of a selection of WWF global priority large mammals and marine species to climate change. However, it divides adaptive capacity into adaptive capability and adaptation opportunity, in order to identify whether adaptation is more constrained by the biology of the species or by its environmental setting. Lack of evidence makes it difficult to apply the framework consistently across the species, but it was found that, particularly for the terrestrial mammals, adaptation opportunities seems to be the greater constraint. This framework and analysis could be used by conservationists and those wishing to enhance the resilience of species to climate change. PMID:24833051

  19. Adaptive interplanetary orbit determination

    NASA Astrophysics Data System (ADS)

    Crain, Timothy Price

    This work documents the development of a real-time interplanetary orbit determination monitoring algorithm for detecting and identifying changes in the spacecraft dynamic and measurement environments. The algorithm may either be utilized in a stand-alone fashion as a spacecraft monitor and hypothesis tester by navigators or may serve as a component in an autonomous adaptive orbit determination architecture. In either application, the monitoring algorithm serves to identify the orbit determination filter parameters to be modified by an offline process to restore the operational model accuracy when the spacecraft environment changes unexpectedly. The monitoring algorithm utilizes a hierarchical mixture-of-experts to regulate a multilevel bank organization of extended Kalman filters. Banks of filters operate on the hierarchy top-level and are composed of filters with configurations representative of a specific environment change called a macromode. Fine differences, or micromodes, within the macromodes are represented by individual filter configurations. Regulation is provided by two levels of single-layer neural networks called gating networks. A single top-level gating network regulates the weighting among macromodes and each bank uses a gating network to regulate member filters internally. Experiments are conducted on the Mars Pathfinder cruise trajectory environment using range and Doppler data from the Deep Space Network. The experiments investigate the ability of the hierarchical mixture-of-experts to identify three environment macromodes: (1) unmodeled impulsive maneuvers, (2) changes in the solar radiation pressure dynamics, and (3) changes in the measurement noise strength. Two methods of initializing the gating networks are examined in each experiment. One method gives the neurons associated with all filters equivalent synaptic weight. The other method places greater weight on the operational filter initially believed to model the spacecraft environment. The

  20. Vision and vestibular adaptation.

    PubMed

    Demer, J L; Crane, B T

    1998-07-01

    gaze on targets at the distances used. This modulation was evident within the first 80 msec of onset of head movement, too early to be caused by immediate visual tracking. Modeling suggests a linear interaction between canal signals and otolith signals scaled by the inverse of target distance. Vestibulo-ocular reflex performance appears to be adapted to stabilize gaze during translational and rotational perturbations that occur during natural activities, as is appropriate for relevant target distances. Although immediate visual tracking contributes little to gaze stabilization during natural activities, visual requirements determine the performance of vestibulo-ocular reflexes arising from both canals and otoliths.

  1. The Limits to Adaptation; A Systems Approach

    EPA Science Inventory

    The Limits to Adaptation: A Systems Approach. The ability to adapt to climate change is delineated by capacity thresholds, after which climate damages begin to overwhelm the adaptation response. Such thresholds depend upon physical properties (natural processes and engineering...

  2. The Limits to Adaptation; A Systems Approach

    EPA Science Inventory

    The Limits to Adaptation: A Systems Approach. The ability to adapt to climate change is delineated by capacity thresholds, after which climate damages begin to overwhelm the adaptation response. Such thresholds depend upon physical properties (natural processes and engineering...

  3. Adaptive hybrid control of manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1987-01-01

    Simple methods for the design of adaptive force and position controllers for robot manipulators within the hybrid control architecuture is presented. The force controller is composed of an adaptive PID feedback controller, an auxiliary signal and a force feedforward term, and it achieves tracking of desired force setpoints in the constraint directions. The position controller consists of adaptive feedback and feedforward controllers and an auxiliary signal, and it accomplishes tracking of desired position trajectories in the free directions. The controllers are capable of compensating for dynamic cross-couplings that exist between the position and force control loops in the hybrid control architecture. The adaptive controllers do not require knowledge of the complex dynamic model or parameter values of the manipulator or the environment. The proposed control schemes are computationally fast and suitable for implementation in on-line control with high sampling rates.

  4. Bridging innate and adaptive immunity.

    PubMed

    Paul, William E

    2011-12-09

    The Nobel Prize in Physiology or Medicine for 2011 to Jules Hoffmann, Bruce Beutler, and the late Ralph Steinman recognizes accomplishments in understanding and unifying the two strands of immunology, the evolutionarily ancient innate immune response and modern adaptive immunity.

  5. Hypermedia Environments and Adaptive Instruction.

    ERIC Educational Resources Information Center

    Federico, Pat-Anthony

    1999-01-01

    Reviews relevant professional literature concerning hypermedia environments and adaptive instruction for online learning for distance education and continuing education. Highlights include aptitude-treatment interaction; cognitive processes; navigational paths; log files; and intelligent tutors. Contains 125 references. (LRW)

  6. How Humans Adapt To Heat

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.; Kaciuba-Uscilko, Hanna

    1992-01-01

    Report discusses adaptive responses of humans to hot environment. Describes thermoregulation by integrated responses of nervous system, vascular/fluid/electrolyte system, and endocrine system. Considers disorders resulting from failure of thermoregulation and less serious heat stress.

  7. How Humans Adapt To Heat

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.; Kaciuba-Uscilko, Hanna

    1992-01-01

    Report discusses adaptive responses of humans to hot environment. Describes thermoregulation by integrated responses of nervous system, vascular/fluid/electrolyte system, and endocrine system. Considers disorders resulting from failure of thermoregulation and less serious heat stress.

  8. Shaft Adapter For Data Coupler

    NASA Technical Reports Server (NTRS)

    Elliott, James R.; Lord, Mark T.

    1990-01-01

    Shaft adapter developed to provide means for securing Acurex 1200B universal data coupler to rotating instrumented shaft. Consists of two major parts: shaft sleeve and shaft clamp. Provides for accurate measurements of stresses and strains in shaft.

  9. Adaptation to delayed auditory feedback

    NASA Technical Reports Server (NTRS)

    Katz, D. I.; Lackner, J. R.

    1977-01-01

    Delayed auditory feedback disrupts the production of speech, causing an increase in speech duration as well as many articulatory errors. To determine whether prolonged exposure to delayed auditory feedback (DAF) leads to adaptive compensations in speech production, 10 subjects were exposed in separate experimental sessions to both incremental and constant-delay exposure conditions. Significant adaptation occurred for syntactically structured stimuli in the form of increased speaking rates. After DAF was removed, aftereffects were apparent for all stimulus types in terms of increased speech rates. A carry-over effect from the first to the second experimental session was evident as long as 29 days after the first session. The use of strategies to overcome DAF and the differences between adaptation to DAF and adaptation to visual rearrangement are discussed.

  10. COMMENTARY:Limits to adaptation

    SciTech Connect

    Preston, Benjamin L

    2013-01-01

    An actor-centered, risk-based approach to defining limits to social adaptation provides a useful analytic framing for identifying and anticipating these limits and informing debates over society s responses to climate change.

  11. Biological adaptabilities and quantum entropies.

    PubMed

    Kirby, Kevin G

    2002-01-01

    The entropy-based theory of adaptability set forth by Michael Conrad in the early 1970s continued to appear in his work for over two decades, and was the subject of the only book he published in his lifetime. He applied this theory to a host of subjects ranging from enzyme dynamics to sociology. This paper reviews the formalism of adaptability theory, clarifying some of its mathematical and interpretive difficulties. The theory frames the computational tradeoff principle, a thesis that was the most frequently recurring claim in his work. The formulation of adaptability theory presented here allows the introduction of quantum entropy functions into the theory, revealing an interesting relationship between adaptability and another one of Conrad's deep preoccupations, the role of quantum processes in life.

  12. Adapted Canoeing for the Handicapped.

    ERIC Educational Resources Information Center

    Frith, Greg H.; Warren, L. D.

    1984-01-01

    Safety as well as instructional recommendations are offered for adapting canoeing as a recreationial activity for handicapped students. Major steps of the instructional program feature orientation to the water and canoe, entry and exit techinques, and mobility procedures. (CL)

  13. Unstructured mesh generation and adaptivity

    NASA Technical Reports Server (NTRS)

    Mavriplis, D. J.

    1995-01-01

    An overview of current unstructured mesh generation and adaptivity techniques is given. Basic building blocks taken from the field of computational geometry are first described. Various practical mesh generation techniques based on these algorithms are then constructed and illustrated with examples. Issues of adaptive meshing and stretched mesh generation for anisotropic problems are treated in subsequent sections. The presentation is organized in an education manner, for readers familiar with computational fluid dynamics, wishing to learn more about current unstructured mesh techniques.

  14. Adaptive oxide electronics: A review

    NASA Astrophysics Data System (ADS)

    Ha, Sieu D.; Ramanathan, Shriram

    2011-10-01

    Novel information processing techniques are being actively explored to overcome fundamental limitations associated with CMOS scaling. A new paradigm of adaptive electronic devices is emerging that may reshape the frontiers of electronics and enable new modalities. Creating systems that can learn and adapt to various inputs has generally been a complex algorithm problem in information science, albeit with wide-ranging and powerful applications from medical diagnosis to control systems. Recent work in oxide electronics suggests that it may be plausible to implement such systems at the device level, thereby drastically increasing computational density and power efficiency and expanding the potential for electronics beyond Boolean computation. Intriguing possibilities of adaptive electronics include fabrication of devices that mimic human brain functionality: the strengthening and weakening of synapses emulated by electrically, magnetically, thermally, or optically tunable properties of materials.In this review, we detail materials and device physics studies on functional metal oxides that may be utilized for adaptive electronics. It has been shown that properties, such as resistivity, polarization, and magnetization, of many oxides can be modified electrically in a non-volatile manner, suggesting that these materials respond to electrical stimulus similarly as a neural synapse. We discuss what device characteristics will likely be relevant for integration into adaptive platforms and then survey a variety of oxides with respect to these properties, such as, but not limited to, TaOx, SrTiO3, and Bi4-xLaxTi3O12. The physical mechanisms in each case are detailed and analyzed within the framework of adaptive electronics. We then review theoretically formulated and current experimentally realized adaptive devices with functional oxides, such as self-programmable logic and neuromorphic circuits. Finally, we speculate on what advances in materials physics and engineering may

  15. Adaptive approaches to biosecurity governance.

    PubMed

    Cook, David C; Liu, Shuang; Murphy, Brendan; Lonsdale, W Mark

    2010-09-01

    This article discusses institutional changes that may facilitate an adaptive approach to biosecurity risk management where governance is viewed as a multidisciplinary, interactive experiment acknowledging uncertainty. Using the principles of adaptive governance, evolved from institutional theory, we explore how the concepts of lateral information flows, incentive alignment, and policy experimentation might shape Australia's invasive species defense mechanisms. We suggest design principles for biosecurity policies emphasizing overlapping complementary response capabilities and the sharing of invasive species risks via a polycentric system of governance.

  16. Adaptive sampling in behavioral surveys.

    PubMed

    Thompson, S K

    1997-01-01

    Studies of populations such as drug users encounter difficulties because the members of the populations are rare, hidden, or hard to reach. Conventionally designed large-scale surveys detect relatively few members of the populations so that estimates of population characteristics have high uncertainty. Ethnographic studies, on the other hand, reach suitable numbers of individuals only through the use of link-tracing, chain referral, or snowball sampling procedures that often leave the investigators unable to make inferences from their sample to the hidden population as a whole. In adaptive sampling, the procedure for selecting people or other units to be in the sample depends on variables of interest observed during the survey, so the design adapts to the population as encountered. For example, when self-reported drug use is found among members of the sample, sampling effort may be increased in nearby areas. Types of adaptive sampling designs include ordinary sequential sampling, adaptive allocation in stratified sampling, adaptive cluster sampling, and optimal model-based designs. Graph sampling refers to situations with nodes (for example, people) connected by edges (such as social links or geographic proximity). An initial sample of nodes or edges is selected and edges are subsequently followed to bring other nodes into the sample. Graph sampling designs include network sampling, snowball sampling, link-tracing, chain referral, and adaptive cluster sampling. A graph sampling design is adaptive if the decision to include linked nodes depends on variables of interest observed on nodes already in the sample. Adjustment methods for nonsampling errors such as imperfect detection of drug users in the sample apply to adaptive as well as conventional designs.

  17. Building An Adaptive Cyber Strategy

    DTIC Science & Technology

    2016-06-01

    AU/ACSC/SMITH, FI/AY16 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY BUILDING AN ADAPTIVE CYBER STRATEGY by...AY16 Abstract Due to the complexity of cyberspace and the diversity of threats that operate in the new domain, current US cyber strategy has not...proven effective. This paper dissects the cyber threat landscape and how advanced threats operate in order to devise an effective, adaptive strategy

  18. Consensus formation on adaptive networks

    NASA Astrophysics Data System (ADS)

    Kozma, Balazs; Barrat, Alain

    2008-01-01

    The structure of a network can significantly influence the properties of the dynamical processes that take place on them. While many studies have been paid to this influence, much less attention has been devoted to the interplay and feedback mechanisms between dynamical processes and network topology on adaptive networks. Adaptive rewiring of links can happen in real life systems such as acquaintance networks, where people are more likely to maintain a social connection if their views and values are similar. In our study, we consider different variants of a model for consensus formation. Our investigations reveal that the adaptation of the network topology fosters cluster formation by enhancing communication between agents of similar opinion, although it also promotes the division of these clusters. The temporal behavior is also strongly affected by adaptivity: while, on static networks, it is influenced by percolation properties, on adaptive networks, both the early and late time evolutions of the system are determined by the rewiring process. The investigation of a variant of the model reveals that the scenarios of transitions between consensus and polarized states are more robust on adaptive networks.

  19. Adaptive capture of expert knowledge

    SciTech Connect

    Barrett, C.L.; Jones, R.D.; Hand, Un Kyong |

    1995-05-01

    A method is introduced that can directly acquire knowledge-engineered, rule-based logic in an adaptive network. This adaptive representation of the rule system can then replace the rule system in simulated intelligent agents and thereby permit further performance-based adaptation of the rule system. The approach described provides both weight-fitting network adaptation and potentially powerful rule mutation and selection mechanisms. Nonlinear terms are generated implicitly in the mutation process through the emergent interaction of multiple linear terms. By this method it is possible to acquire nonlinear relations that exist in the training data without addition of hidden layers or imposition of explicit nonlinear terms in the network. We smoothed and captured a set of expert rules with an adaptive network. The motivation for this was to (1) realize a speed advantage over traditional rule-based simulations; (2) have variability in the intelligent objects not possible by rule-based systems but provided by adaptive systems: and (3) maintain the understandability of rule-based simulations. A set of binary rules was smoothed and converted into a simple set of arithmetic statements, where continuous, non-binary rules are permitted. A neural network, called the expert network, was developed to capture this rule set, which it was able to do with zero error. The expert network is also capable of learning a nonmonotonic term without a hidden layer. The trained network in feedforward operation is fast running, compact, and traceable to the rule base.

  20. Knowledge-based media adaptation

    NASA Astrophysics Data System (ADS)

    Leopold, Klaus; Jannach, Dietmar; Hellwagner, Hermann

    2004-10-01

    This paper introduces the principal approach and describes the basic architecture and current implementation of the knowledge-based multimedia adaptation framework we are currently developing. The framework can be used in Universal Multimedia Access scenarios, where multimedia content has to be adapted to specific usage environment parameters (network and client device capabilities, user preferences). Using knowledge-based techniques (state-space planning), the framework automatically computes an adaptation plan, i.e., a sequence of media conversion operations, to transform the multimedia resources to meet the client's requirements or constraints. The system takes as input standards-compliant descriptions of the content (using MPEG-7 metadata) and of the target usage environment (using MPEG-21 Digital Item Adaptation metadata) to derive start and goal states for the planning process, respectively. Furthermore, declarative descriptions of the conversion operations (such as available via software library functions) enable existing adaptation algorithms to be invoked without requiring programming effort. A running example in the paper illustrates the descriptors and techniques employed by the knowledge-based media adaptation system.

  1. Adapting agriculture to climate change.

    PubMed

    Howden, S Mark; Soussana, Jean-François; Tubiello, Francesco N; Chhetri, Netra; Dunlop, Michael; Meinke, Holger

    2007-12-11

    The strong trends in climate change already evident, the likelihood of further changes occurring, and the increasing scale of potential climate impacts give urgency to addressing agricultural adaptation more coherently. There are many potential adaptation options available for marginal change of existing agricultural systems, often variations of existing climate risk management. We show that implementation of these options is likely to have substantial benefits under moderate climate change for some cropping systems. However, there are limits to their effectiveness under more severe climate changes. Hence, more systemic changes in resource allocation need to be considered, such as targeted diversification of production systems and livelihoods. We argue that achieving increased adaptation action will necessitate integration of climate change-related issues with other risk factors, such as climate variability and market risk, and with other policy domains, such as sustainable development. Dealing with the many barriers to effective adaptation will require a comprehensive and dynamic policy approach covering a range of scales and issues, for example, from the understanding by farmers of change in risk profiles to the establishment of efficient markets that facilitate response strategies. Science, too, has to adapt. Multidisciplinary problems require multidisciplinary solutions, i.e., a focus on integrated rather than disciplinary science and a strengthening of the interface with decision makers. A crucial component of this approach is the implementation of adaptation assessment frameworks that are relevant, robust, and easily operated by all stakeholders, practitioners, policymakers, and scientists.

  2. Adaptive walking in Alzheimer's disease.

    PubMed

    Orcioli-Silva, Diego; Simieli, Lucas; Barbieri, Fabio Augusto; Stella, Florindo; Gobbi, Lilian Teresa Bucken

    2012-01-01

    The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients.

  3. Adaptive Walking in Alzheimer's Disease

    PubMed Central

    Orcioli-Silva, Diego; Simieli, Lucas; Barbieri, Fabio Augusto; Stella, Florindo; Gobbi, Lilian Teresa Bucken

    2012-01-01

    The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients. PMID:22991684

  4. Adapting agriculture to climate change

    PubMed Central

    Howden, S. Mark; Soussana, Jean-François; Tubiello, Francesco N.; Chhetri, Netra; Dunlop, Michael; Meinke, Holger

    2007-01-01

    The strong trends in climate change already evident, the likelihood of further changes occurring, and the increasing scale of potential climate impacts give urgency to addressing agricultural adaptation more coherently. There are many potential adaptation options available for marginal change of existing agricultural systems, often variations of existing climate risk management. We show that implementation of these options is likely to have substantial benefits under moderate climate change for some cropping systems. However, there are limits to their effectiveness under more severe climate changes. Hence, more systemic changes in resource allocation need to be considered, such as targeted diversification of production systems and livelihoods. We argue that achieving increased adaptation action will necessitate integration of climate change-related issues with other risk factors, such as climate variability and market risk, and with other policy domains, such as sustainable development. Dealing with the many barriers to effective adaptation will require a comprehensive and dynamic policy approach covering a range of scales and issues, for example, from the understanding by farmers of change in risk profiles to the establishment of efficient markets that facilitate response strategies. Science, too, has to adapt. Multidisciplinary problems require multidisciplinary solutions, i.e., a focus on integrated rather than disciplinary science and a strengthening of the interface with decision makers. A crucial component of this approach is the implementation of adaptation assessment frameworks that are relevant, robust, and easily operated by all stakeholders, practitioners, policymakers, and scientists. PMID:18077402

  5. Adapting to life: ocean biogeochemical modelling and adaptive remeshing

    NASA Astrophysics Data System (ADS)

    Hill, J.; Popova, E. E.; Ham, D. A.; Piggott, M. D.; Srokosz, M.

    2014-05-01

    An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in vertical nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a simple vertical column (quasi-1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2-3. Unlike previous work the adaptivity metric used is flexible and we show that capturing the physical behaviour of the model is paramount to achieving a reasonable solution. Adding biological quantities to the adaptivity metric further refines the solution. We then show the potential of this method in two case studies where we change the adaptivity metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate that adaptive meshes may provide a suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high vertical resolution whilst minimising the number of elements in the mesh. More

  6. Adaptive Liquid Crystal Windows

    SciTech Connect

    Taheri, Bahman; Bodnar, Volodymyr

    2011-12-31

    Energy consumption by private and commercial sectors in the U.S. has steadily grown over the last decade. The uncertainty in future availability of imported oil, on which the energy consumption relies strongly, resulted in a dramatic increase in the cost of energy. About 20% of this consumption are used to heat and cool houses and commercial buildings. To reduce dependence on the foreign oil and cut down emission of greenhouse gases, it is necessary to eliminate losses and reduce total energy consumption by buildings. To achieve this goal it is necessary to redefine the role of the conventional windows. At a minimum, windows should stop being a source for energy loss. Ideally, windows should become a source of energy, providing net gain to reduce energy used to heat and cool homes. It is possible to have a net energy gain from a window if its light transmission can be dynamically altered, ideally electronically without the need of operator assistance, providing optimal control of the solar gain that varies with season and climate in the U.S. In addition, the window must not require power from the building for operation. Resolution of this problem is a societal challenge and of national interest and will have a broad global impact. For this purpose, the year-round, allclimate window solution to provide an electronically variable solar heat gain coefficient (SHGC) with a wide dynamic range is needed. AlphaMicron, Inc. (AMI) developed and manufactured 1ft × 1ft prototype panels for the world’s first auto-adjusting Adaptive Liquid Crystal Windows (ALCWs) that can operate from sunlight without the need for external power source and demonstrate an electronically adjustable SHGC. This novel windows are based on AlphaMicron’s patented e-Tint® technology, a guesthost liquid crystal system implemented on flexible, optically clear plastic films. This technology is suitable both for OEM and aftermarket (retro-fitting) lamination to new and existing windows. Low level of

  7. Rebound: A Framework for Automated Component Adaptation

    NASA Technical Reports Server (NTRS)

    Penix, John; Lau, Sonie (Technical Monitor)

    1998-01-01

    The REBOUND adaptation framework organizes a collection of adaptation tactics in a way that they can be selected based on the components available for adaptation. Adaptation tactics are specified formally in terms of the relationship between the component to be adapted and the resulting adapted component. The tactic specifications are used as matching conditions for specification-based component retrieval, creating a 'retrieval for adaptation' scenario. The results of specification matching are used to guide component adaptation. Several examples illustrate how the framework guides component and tactic selection and how basic tactics are composed to form more powerful tactics.

  8. Biochemical adaptation to ocean acidification.

    PubMed

    Stillman, Jonathon H; Paganini, Adam W

    2015-06-01

    The change in oceanic carbonate chemistry due to increased atmospheric PCO2  has caused pH to decline in marine surface waters, a phenomenon known as ocean acidification (OA). The effects of OA on organisms have been shown to be widespread among diverse taxa from a wide range of habitats. The majority of studies of organismal response to OA are in short-term exposures to future levels of PCO2 . From such studies, much information has been gathered on plastic responses organisms may make in the future that are beneficial or harmful to fitness. Relatively few studies have examined whether organisms can adapt to negative-fitness consequences of plastic responses to OA. We outline major approaches that have been used to study the adaptive potential for organisms to OA, which include comparative studies and experimental evolution. Organisms that inhabit a range of pH environments (e.g. pH gradients at volcanic CO2 seeps or in upwelling zones) have great potential for studies that identify adaptive shifts that have occurred through evolution. Comparative studies have advanced our understanding of adaptation to OA by linking whole-organism responses with cellular mechanisms. Such optimization of function provides a link between genetic variation and adaptive evolution in tuning optimal function of rate-limiting cellular processes in different pH conditions. For example, in experimental evolution studies of organisms with short generation times (e.g. phytoplankton), hundreds of generations of growth under future conditions has resulted in fixed differences in gene expression related to acid-base regulation. However, biochemical mechanisms for adaptive responses to OA have yet to be fully characterized, and are likely to be more complex than simply changes in gene expression or protein modification. Finally, we present a hypothesis regarding an unexplored area for biochemical adaptation to ocean acidification. In this hypothesis, proteins and membranes exposed to the

  9. Three timescales in prism adaptation.

    PubMed

    Inoue, Masato; Uchimura, Motoaki; Karibe, Ayaka; O'Shea, Jacinta; Rossetti, Yves; Kitazawa, Shigeru

    2015-01-01

    It has been proposed that motor adaptation depends on at least two learning systems, one that learns fast but with poor retention and another that learns slowly but with better retention (Smith MA, Ghazizadeh A, Shadmehr R. PLoS Biol 4: e179, 2006). This two-state model has been shown to account for a range of behavior in the force field adaptation task. In the present study, we examined whether such a two-state model could also account for behavior arising from adaptation to a prismatic displacement of the visual field. We first confirmed that an "adaptation rebound," a critical prediction of the two-state model, occurred when visual feedback was deprived after an adaptation-extinction episode. We then examined the speed of decay of the prism aftereffect (without any visual feedback) after repetitions of 30, 150, and 500 trials of prism exposure. The speed of decay decreased with the number of exposure trials, a phenomenon that was best explained by assuming an "ultraslow" system, in addition to the fast and slow systems. Finally, we compared retention of aftereffects 24 h after 150 or 500 trials of exposure: retention was significantly greater after 500 than 150 trials. This difference in retention could not be explained by the two-state model but was well explained by the three-state model as arising from the difference in the amount of adaptation of the "ultraslow process." These results suggest that there are not only fast and slow systems but also an ultraslow learning system in prism adaptation that is activated by prolonged prism exposure of 150-500 trials.

  10. An Adaptive Critic Approach to Reference Model Adaptation

    NASA Technical Reports Server (NTRS)

    Krishnakumar, K.; Limes, G.; Gundy-Burlet, K.; Bryant, D.

    2003-01-01

    Neural networks have been successfully used for implementing control architectures for different applications. In this work, we examine a neural network augmented adaptive critic as a Level 2 intelligent controller for a C- 17 aircraft. This intelligent control architecture utilizes an adaptive critic to tune the parameters of a reference model, which is then used to define the angular rate command for a Level 1 intelligent controller. The present architecture is implemented on a high-fidelity non-linear model of a C-17 aircraft. The goal of this research is to improve the performance of the C-17 under degraded conditions such as control failures and battle damage. Pilot ratings using a motion based simulation facility are included in this paper. The benefits of using an adaptive critic are documented using time response comparisons for severe damage situations.

  11. Molecular evolution and thermal adaptation

    NASA Astrophysics Data System (ADS)

    Chen, Peiqiu

    2011-12-01

    In this thesis, we address problems in molecular evolution, thermal adaptation, and the kinetics of adaptation of bacteria and viruses to elevated environmental temperatures. We use a nearly neutral fitness model where the replication speed of an organism is proportional to the copy number of folded proteins. Our model reproduces the distribution of stabilities of natural proteins in excellent agreement with experiment. We find that species with high mutation rates tend to have less stable proteins compared to species with low mutation rate. We found that a broad distribution of protein stabilities observed in the model and in experiment is the key determinant of thermal response for viruses and bacteria. Our results explain most of the earlier experimental observations: striking asymmetry of thermal response curves, the absence of evolutionary trade-off which was expected but not found in experiments, correlation between denaturation temperature for several protein families and the Optimal Growth Temperature (OGT) of their carrier organisms, and proximity of bacterial or viral OGTs to their evolutionary temperatures. Our theory quantitatively and with high accuracy described thermal response curves for 35 bacterial species. The model also addresses the key to adaptation is in weak-link genes (WLG), which encode least thermodynamically stable essential proteins in the proteome. We observe, as in experiment, a two-stage adaptation process. The first stage is a Luria-Delbruck type of selection, whereby rare WLG alleles, whose proteins are more stable than WLG proteins of the majority of the population (either due to standing genetic variation or due to an early acquired mutation), rapidly rise to fixation. The second stage constitutes subsequent slow accumulation of mutations in an adapted population. As adaptation progresses, selection regime changes from positive to neutral: Selection coefficient of beneficial mutations scales as a negative power of number of

  12. Numerosity perception after size adaptation

    PubMed Central

    Zimmermann, Eckart; Fink, Gereon R.

    2016-01-01

    While some researchers propose the existence of a special numerosity sense, others challenge this view and argue that numerosity is derived from low-level features as density information. Here, we used size adaptation to manipulate the apparent area size of an object set without changing its physical density. After size adaptation, two probe patches were shown, each of which contained a specific numerosity of dots. Subjects were required to report, which probe patch contained more dots. Numerosity perception was compared between conditions where probe patches were adapted to appear smaller or larger. Size adaptation affected numerosity perception in a logarithmic fashion, increasing with the numerosity in the probe patch. No changes in density perception were found after size adaptation. Data suggest that size and density information play only a minor role in the estimation of low numerosities. In stark contrast, high numerosities strongly depend on size and density information. The data reinforce recent claims of separate mechanism for the perception of low and high numerosities. PMID:27650296

  13. Adaptive evolution of molecular phenotypes

    NASA Astrophysics Data System (ADS)

    Held, Torsten; Nourmohammad, Armita; Lässig, Michael

    2014-09-01

    Molecular phenotypes link genomic information with organismic functions, fitness, and evolution. Quantitative traits are complex phenotypes that depend on multiple genomic loci. In this paper, we study the adaptive evolution of a quantitative trait under time-dependent selection, which arises from environmental changes or through fitness interactions with other co-evolving phenotypes. We analyze a model of trait evolution under mutations and genetic drift in a single-peak fitness seascape. The fitness peak performs a constrained random walk in the trait amplitude, which determines the time-dependent trait optimum in a given population. We derive analytical expressions for the distribution of the time-dependent trait divergence between populations and of the trait diversity within populations. Based on this solution, we develop a method to infer adaptive evolution of quantitative traits. Specifically, we show that the ratio of the average trait divergence and the diversity is a universal function of evolutionary time, which predicts the stabilizing strength and the driving rate of the fitness seascape. From an information-theoretic point of view, this function measures the macro-evolutionary entropy in a population ensemble, which determines the predictability of the evolutionary process. Our solution also quantifies two key characteristics of adapting populations: the cumulative fitness flux, which measures the total amount of adaptation, and the adaptive load, which is the fitness cost due to a population's lag behind the fitness peak.

  14. Hydropower, Adaptive Management, and Biodiversity

    PubMed

    WIERINGA; MORTON

    1996-11-01

    / Adaptive management is a policy framework within which an iterative process of decision making is followed based on the observed responses to and effectiveness of previous decisions. The use of adaptive management allows science-based research and monitoring of natural resource and ecological community responses, in conjunction with societal values and goals, to guide decisions concerning man's activities. The adaptive management process has been proposed for application to hydropower operations at Glen Canyon Dam on the Colorado River, a situation that requires complex balancing of natural resources requirements and competing human uses. This example is representative of the general increase in public interest in the operation of hydropower facilities and possible effects on downstream natural resources and of the growing conflicts between uses and users of river-based resources. This paper describes the adaptive management process, using the Glen Canyon Dam example, and discusses ways to make the process work effectively in managing downstream natural resources and biodiversity. KEY WORDS: Adaptive management; Biodiversity; Hydropower; Glen Canyon Dam; Ecology

  15. Dynamic patterns of adaptive radiation.

    PubMed

    Gavrilets, Sergey; Vose, Aaron

    2005-12-13

    Adaptive radiation is defined as the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage. When it occurs, adaptive radiation typically follows the colonization of a new environment or the establishment of a "key innovation," which opens new ecological niches and/or new paths for evolution. Here, we take advantage of recent developments in speciation theory and modern computing power to build and explore a large-scale, stochastic, spatially explicit, individual-based model of adaptive radiation driven by adaptation to multidimensional ecological niches. We are able to model evolutionary dynamics of populations with hundreds of thousands of sexual diploid individuals over a time span of 100,000 generations assuming realistic mutation rates and allowing for genetic variation in a large number of both selected and neutral loci. Our results provide theoretical support and explanation for a number of empirical patterns including "area effect," "overshooting effect," and "least action effect," as well as for the idea of a "porous genome." Our findings suggest that the genetic architecture of traits involved in the most spectacular radiations might be rather simple. We show that a great majority of speciation events are concentrated early in the phylogeny. Our results emphasize the importance of ecological opportunity and genetic constraints in controlling the dynamics of adaptive radiation.

  16. Protein Adaptations in Archaeal Extremophiles

    PubMed Central

    Reed, Christopher J.; Lewis, Hunter; Trejo, Eric; Winston, Vern; Evilia, Caryn

    2013-01-01

    Extremophiles, especially those in Archaea, have a myriad of adaptations that keep their cellular proteins stable and active under the extreme conditions in which they live. Rather than having one basic set of adaptations that works for all environments, Archaea have evolved separate protein features that are customized for each environment. We categorized the Archaea into three general groups to describe what is known about their protein adaptations: thermophilic, psychrophilic, and halophilic. Thermophilic proteins tend to have a prominent hydrophobic core and increased electrostatic interactions to maintain activity at high temperatures. Psychrophilic proteins have a reduced hydrophobic core and a less charged protein surface to maintain flexibility and activity under cold temperatures. Halophilic proteins are characterized by increased negative surface charge due to increased acidic amino acid content and peptide insertions, which compensates for the extreme ionic conditions. While acidophiles, alkaliphiles, and piezophiles are their own class of Archaea, their protein adaptations toward pH and pressure are less discernible. By understanding the protein adaptations used by archaeal extremophiles, we hope to be able to engineer and utilize proteins for industrial, environmental, and biotechnological applications where function in extreme conditions is required for activity. PMID:24151449

  17. Protein adaptations in archaeal extremophiles.

    PubMed

    Reed, Christopher J; Lewis, Hunter; Trejo, Eric; Winston, Vern; Evilia, Caryn

    2013-01-01

    Extremophiles, especially those in Archaea, have a myriad of adaptations that keep their cellular proteins stable and active under the extreme conditions in which they live. Rather than having one basic set of adaptations that works for all environments, Archaea have evolved separate protein features that are customized for each environment. We categorized the Archaea into three general groups to describe what is known about their protein adaptations: thermophilic, psychrophilic, and halophilic. Thermophilic proteins tend to have a prominent hydrophobic core and increased electrostatic interactions to maintain activity at high temperatures. Psychrophilic proteins have a reduced hydrophobic core and a less charged protein surface to maintain flexibility and activity under cold temperatures. Halophilic proteins are characterized by increased negative surface charge due to increased acidic amino acid content and peptide insertions, which compensates for the extreme ionic conditions. While acidophiles, alkaliphiles, and piezophiles are their own class of Archaea, their protein adaptations toward pH and pressure are less discernible. By understanding the protein adaptations used by archaeal extremophiles, we hope to be able to engineer and utilize proteins for industrial, environmental, and biotechnological applications where function in extreme conditions is required for activity.

  18. Visual adaptation and face perception

    PubMed Central

    Webster, Michael A.; MacLeod, Donald I. A.

    2011-01-01

    The appearance of faces can be strongly affected by the characteristics of faces viewed previously. These perceptual after-effects reflect processes of sensory adaptation that are found throughout the visual system, but which have been considered only relatively recently in the context of higher level perceptual judgements. In this review, we explore the consequences of adaptation for human face perception, and the implications of adaptation for understanding the neural-coding schemes underlying the visual representation of faces. The properties of face after-effects suggest that they, in part, reflect response changes at high and possibly face-specific levels of visual processing. Yet, the form of the after-effects and the norm-based codes that they point to show many parallels with the adaptations and functional organization that are thought to underlie the encoding of perceptual attributes like colour. The nature and basis for human colour vision have been studied extensively, and we draw on ideas and principles that have been developed to account for norms and normalization in colour vision to consider potential similarities and differences in the representation and adaptation of faces. PMID:21536555

  19. Exploiting Adaptive Optics with Deformable Secondary Mirrors

    DTIC Science & Technology

    2007-03-08

    progress in tomographic wavefront sensing and altitude conjugated adaptive correction, and is a critical step forward for adaptive optics for future large...geostationary satellites, captured at the 6.5 m MMT telescope, using the deformable secondary adaptive optics system....new technology to the unique development of deformable secondary mirrors pioneered at the University of Arizona’s Center for Astronomical Adaptive

  20. Toward Adaptability: Where to from Here?

    ERIC Educational Resources Information Center

    Parsons, Seth A.; Vaughn, Margaret

    2016-01-01

    In this article, the collection of articles in this issue are synthesized to discuss conceptualizations of adaptive teaching as a means to foster spaces for adaptive teaching in today's complex educational system. Themes that exist across this collection of articles include adaptive teachers as constructivists, adaptive teachers as knowledgeable…

  1. Adaptive sampling for noisy problems

    SciTech Connect

    Cantu-Paz, E

    2004-03-26

    The usual approach to deal with noise present in many real-world optimization problems is to take an arbitrary number of samples of the objective function and use the sample average as an estimate of the true objective value. The number of samples is typically chosen arbitrarily and remains constant for the entire optimization process. This paper studies an adaptive sampling technique that varies the number of samples based on the uncertainty of deciding between two individuals. Experiments demonstrate the effect of adaptive sampling on the final solution quality reached by a genetic algorithm and the computational cost required to find the solution. The results suggest that the adaptive technique can effectively eliminate the need to set the sample size a priori, but in many cases it requires high computational costs.

  2. Memory distortion: an adaptive perspective

    PubMed Central

    Schacter, Daniel L.; Guerin, Scott A.; St. Jacques, Peggy L.

    2011-01-01

    Memory is prone to distortions that can have serious consequences in everyday life. Here we integrate emerging evidence that several types of memory distortions – imagination inflation, gist-based and associative memory errors, and post-event misinformation – reflect adaptive cognitive processes that contribute to the efficient functioning of memory, but produce distortions as a consequence of doing so. We consider recent cognitive and neuroimaging studies that link these distortions with adaptive processes, including simulation of future events, semantic and contextual encoding, creativity, and memory updating. We also discuss new evidence concerning factors that can influence the occurrence of memory distortions, such as sleep and retrieval conditions, as well as conceptual issues related to the development of an adaptive perspective. PMID:21908231

  3. Adaptive Optics for Large Telescopes

    SciTech Connect

    Olivier, S

    2008-06-27

    The use of adaptive optics was originally conceived by astronomers seeking to correct the blurring of images made with large telescopes due to the effects of atmospheric turbulence. The basic idea is to use a device, a wave front corrector, to adjust the phase of light passing through an optical system, based on some measurement of the spatial variation of the phase transverse to the light propagation direction, using a wave front sensor. Although the original concept was intended for application to astronomical imaging, the technique can be more generally applied. For instance, adaptive optics systems have been used for several decades to correct for aberrations in high-power laser systems. At Lawrence Livermore National Laboratory (LLNL), the world's largest laser system, the National Ignition Facility, uses adaptive optics to correct for aberrations in each of the 192 beams, all of which must be precisely focused on a millimeter scale target in order to perform nuclear physics experiments.

  4. Architecture for Adaptive Intelligent Systems

    NASA Technical Reports Server (NTRS)

    Hayes-Roth, Barbara

    1993-01-01

    We identify a class of niches to be occupied by 'adaptive intelligent systems (AISs)'. In contrast with niches occupied by typical AI agents, AIS niches present situations that vary dynamically along several key dimensions: different combinations of required tasks, different configurations of available resources, contextual conditions ranging from benign to stressful, and different performance criteria. We present a small class hierarchy of AIS niches that exhibit these dimensions of variability and describe a particular AIS niche, ICU (intensive care unit) patient monitoring, which we use for illustration throughout the paper. We have designed and implemented an agent architecture that supports all of different kinds of adaptation by exploiting a single underlying theoretical concept: An agent dynamically constructs explicit control plans to guide its choices among situation-triggered behaviors. We illustrate the architecture and its support for adaptation with examples from Guardian, an experimental agent for ICU monitoring.

  5. Imaging an Adapted Dentoalveolar Complex

    PubMed Central

    Herber, Ralf-Peter; Fong, Justine; Lucas, Seth A.; Ho, Sunita P.

    2012-01-01

    Adaptation of a rat dentoalveolar complex was illustrated using various imaging modalities. Micro-X-ray computed tomography for 3D modeling, combined with complementary techniques, including image processing, scanning electron microscopy, fluorochrome labeling, conventional histology (H&E, TRAP), and immunohistochemistry (RANKL, OPN) elucidated the dynamic nature of bone, the periodontal ligament-space, and cementum in the rat periodontium. Tomography and electron microscopy illustrated structural adaptation of calcified tissues at a higher resolution. Ongoing biomineralization was analyzed using fluorochrome labeling, and by evaluating attenuation profiles using virtual sections from 3D tomographies. Osteoclastic distribution as a function of anatomical location was illustrated by combining histology, immunohistochemistry, and tomography. While tomography and SEM provided past resorption-related events, future adaptive changes were deduced by identifying matrix biomolecules using immunohistochemistry. Thus, a dynamic picture of the dentoalveolar complex in rats was illustrated. PMID:22567314

  6. Adaptive Radiation for Lung Cancer

    PubMed Central

    Gomez, Daniel R.; Chang, Joe Y.

    2011-01-01

    The challenges of lung cancer radiotherapy are intra/inter-fraction tumor/organ anatomy/motion changes and the need to spare surrounding critical structures. Evolving radiotherapy technologies, such as four-dimensional (4D) image-based motion management, daily on-board imaging and adaptive radiotherapy based on volumetric images over the course of radiotherapy, have enabled us to deliver higher dose to target while minimizing normal tissue toxicities. The image-guided radiotherapy adapted to changes of motion and anatomy has made the radiotherapy more precise and allowed ablative dose delivered to the target using novel treatment approaches such as intensity-modulated radiation therapy, stereotactic body radiation therapy, and proton therapy in lung cancer, techniques used to be considered very sensitive to motion change. Future clinical trials using real time tracking and biological adaptive radiotherapy based on functional images are proposed. PMID:20814539

  7. Adaptive Sampling in Hierarchical Simulation

    SciTech Connect

    Knap, J; Barton, N R; Hornung, R D; Arsenlis, A; Becker, R; Jefferson, D R

    2007-07-09

    We propose an adaptive sampling methodology for hierarchical multi-scale simulation. The method utilizes a moving kriging interpolation to significantly reduce the number of evaluations of finer-scale response functions to provide essential constitutive information to a coarser-scale simulation model. The underlying interpolation scheme is unstructured and adaptive to handle the transient nature of a simulation. To handle the dynamic construction and searching of a potentially large set of finer-scale response data, we employ a dynamic metric tree database. We study the performance of our adaptive sampling methodology for a two-level multi-scale model involving a coarse-scale finite element simulation and a finer-scale crystal plasticity based constitutive law.

  8. Adaptive optical label packet switching

    NASA Astrophysics Data System (ADS)

    Xiao, Shilin; Liu, Zhixin; Liang, Zheng; Zhao, Zhihui; Qu, Kefeng

    2007-11-01

    This paper introduces a kind of Adaptive Optical Label Packet Switching (AOLPS) technology. Based on Optical Packet Switching (OPS), AOLPS uses optical label to achieve self-routing, and the size of optical packet is self-adaptive. At the edge nodes, IP packets are fist classified into different first-in-fist-out memories (FIFOs) according to their priority levels and destinations, and then being encapsulated into optical packets. The traffic at each FIFO is real-time monitored, and the controller in edge node employs an optimal strategy to generate suitable sized packets for transmission. Large sized packets will be adopted when traffic is heavy, and small sized packets will be used when traffic is light. This self-adaptive switching granularity can greatly improve the network performance.

  9. Training Adaptive Decision-Making.

    SciTech Connect

    Abbott, Robert G.; Forsythe, James C.

    2014-10-01

    Adaptive Thinking has been defined here as the capacity to recognize when a course of action that may have previously been effective is no longer effective and there is need to adjust strategy. Research was undertaken with human test subjects to identify the factors that contribute to adaptive thinking. It was discovered that those most effective in settings that call for adaptive thinking tend to possess a superior capacity to quickly and effectively generate possible courses of action, as measured using the Category Generation test. Software developed for this research has been applied to develop capabilities enabling analysts to identify crucial factors that are predictive of outcomes in fore-on-force simulation exercises.

  10. [Head and neck adaptive radiotherapy].

    PubMed

    Graff, P; Huger, S; Kirby, N; Pouliot, J

    2013-10-01

    Onboard volumetric imaging systems can provide accurate data of the patient's anatomy during a course of head and neck radiotherapy making it possible to assess the actual delivered dose and to evaluate the dosimetric impact of complex daily positioning variations and gradual anatomic changes such as geometric variations of tumors and normal tissues or shrinkage of external contours. Adaptive radiotherapy is defined as the correction of a patient's treatment planning to adapt for individual variations observed during treatment. Strategies are developed to selectively identify patients that require replanning because of an intolerable dosimetric drift. Automated tools are designed to limit time consumption. Deformable image registration algorithms are the cornerstones of these strategies, but a better understanding of their limits of validity is required before adaptive radiotherapy can be safely introduced to daily practice. Moreover, strict evaluation of the clinical benefits is yet to be proven.

  11. Thermal sensation and cell adaptability

    NASA Astrophysics Data System (ADS)

    Auliciems, Andris

    2014-04-01

    Whole person adaptive comfort is discussed with reference to recent findings in molecular scale systems biology. The observations are upscaled to hypotheses relating to less traditional interpretations of thermal processes, which have new implications for indoor climate management and design. Arguments are presented for a revision of current focus, model and paradigm. The issue is seen as a problem of integrating theoretical development, conceptual modeling and as an investigation of the extent to which environments and acclimatization can be used to achieve individual fitness and health, not only at the subjective comfort level, as hitherto promoted. It is argued that there are many questions yet to be asked about adaptability before celebrating a particular adaptive state.

  12. Limits of adaptation, residual interferences

    NASA Technical Reports Server (NTRS)

    Mokry, Miroslav (Editor); Erickson, J. C., Jr.; Goodyer, Michael J.; Mignosi, Andre; Russo, Giuseppe P.; Smith, J.; Wedemeyer, Erich H.; Newman, Perry A.

    1990-01-01

    Methods of determining linear residual wall interference appear to be well established theoretically; however they need to be validated, for example by comparative studies of test data on the same model in different adaptive-wall wind tunnels as well as in passive, ventilated-wall tunnels. The GARTEur CAST 7 and the CAST 10/DOA 2 investigations are excellent examples of such comparative studies. Results to date in both one-variable and two-variable methods for nonlinear wall interference indicate that a great deal more research and validation are required. The status in 2D flow is advanced over that in 3D flow as is the case generally with adaptive-wall development. Nevertheless, it is now well established that for transonic testing with extensive supercritical flow present, significant wall interference is likely to exist in conventional ventilated test sections. Consequently, residual correction procedures require further development hand-in-hand with further adaptive-wall development.

  13. [Health: an adaptive complex system].

    PubMed

    Toro-Palacio, Luis Fernando; Ochoa-Jaramillo, Francisco Luis

    2012-02-01

    This article points out the enormous gap that exists between complex thinking of an intellectual nature currently present in our environment, and complex experimental thinking that has facilitated the scientific and technological advances that have radically changed the world. The article suggests that life, human beings, global society, and all that constitutes health be considered as adaptive complex systems. This idea, in turn, prioritizes the adoption of a different approach that seeks to expand understanding. When this rationale is recognized, the principal characteristics and emerging properties of health as an adaptive complex system are sustained, following a care and services delivery model. Finally, some pertinent questions from this perspective are put forward in terms of research, and a series of appraisals are expressed that will hopefully serve to help us understand all that we have become as individuals and as a species. The article proposes that the delivery of health care services be regarded as an adaptive complex system.

  14. Parallel Adaptive Mesh Refinement Library

    NASA Technical Reports Server (NTRS)

    Mac-Neice, Peter; Olson, Kevin

    2005-01-01

    Parallel Adaptive Mesh Refinement Library (PARAMESH) is a package of Fortran 90 subroutines designed to provide a computer programmer with an easy route to extension of (1) a previously written serial code that uses a logically Cartesian structured mesh into (2) a parallel code with adaptive mesh refinement (AMR). Alternatively, in its simplest use, and with minimal effort, PARAMESH can operate as a domain-decomposition tool for users who want to parallelize their serial codes but who do not wish to utilize adaptivity. The package builds a hierarchy of sub-grids to cover the computational domain of a given application program, with spatial resolution varying to satisfy the demands of the application. The sub-grid blocks form the nodes of a tree data structure (a quad-tree in two or an oct-tree in three dimensions). Each grid block has a logically Cartesian mesh. The package supports one-, two- and three-dimensional models.

  15. Thermal sensation and cell adaptability.

    PubMed

    Auliciems, Andris

    2014-04-01

    Whole person adaptive comfort is discussed with reference to recent findings in molecular scale systems biology. The observations are upscaled to hypotheses relating to less traditional interpretations of thermal processes, which have new implications for indoor climate management and design. Arguments are presented for a revision of current focus, model and paradigm. The issue is seen as a problem of integrating theoretical development, conceptual modeling and as an investigation of the extent to which environments and acclimatization can be used to achieve individual fitness and health, not only at the subjective comfort level, as hitherto promoted. It is argued that there are many questions yet to be asked about adaptability before celebrating a particular adaptive state.

  16. MMT adaptive secondary prototype development

    NASA Astrophysics Data System (ADS)

    Biasi, Roberto; Gallieni, Daniele

    1998-09-01

    We designed and manufacture dan 'Adaptive Secondary Mirror 30 Actuators Prototype' that represents as much as possible the final MMT adaptive optics unit for what concerns mechanical, electronic and cooling system issues. Moreover, different actuator designs have been tested by using the same test bench. The adaptive secondary is based on a thin continuous facesheet mirror moved by electromagnetic actuators. Permanent magnets are glued on the mirror, while voice coils are connected to the support structure by cold fingers. A capacitive sensor co-located with each actuator measures the local gap between the mirror and a reference back plate. Voice coil motors allow to perform chopping and tip-tilt correction by using directly the deformable mirror. Actuators pitch is set to achieve high order correction in the visible wavelength.

  17. 3D Structured Grid Adaptation

    NASA Technical Reports Server (NTRS)

    Banks, D. W.; Hafez, M. M.

    1996-01-01

    Grid adaptation for structured meshes is the art of using information from an existing, but poorly resolved, solution to automatically redistribute the grid points in such a way as to improve the resolution in regions of high error, and thus the quality of the solution. This involves: (1) generate a grid vis some standard algorithm, (2) calculate a solution on this grid, (3) adapt the grid to this solution, (4) recalculate the solution on this adapted grid, and (5) repeat steps 3 and 4 to satisfaction. Steps 3 and 4 can be repeated until some 'optimal' grid is converged to but typically this is not worth the effort and just two or three repeat calculations are necessary. They also may be repeated every 5-10 time steps for unsteady calculations.

  18. Seasonal adaptations in arctic insects.

    PubMed

    Danks, Hugh V

    2004-04-01

    Many insect species live in the arctic and show a wide range of adaptations to its extreme severity and seasonality. Long, cold winters are met, for example, by cold hardiness and choice of protected sites. Cold hardiness includes both widespread tolerance to freezing and extreme supercooling ability, as well as unusual responses in a few species, such as lack of typical cryoprotectants. Adaptations to short, cool summers include activity at low temperatures, selection of warm habitats and microhabitats, melanism and hairiness coupled with basking behaviour, and prolonged or abbreviated life cycles. Diapause ensures that many species emerge early in summer, with brief synchronized reproduction that maximizes the time for offspring development before winter returns. Some species overwinter in sites that thaw earliest in spring, even if they are relatively exposed in winter. Other adaptations respond to year-to-year variability: for example, prolonged diapause can provide insurance against unsuitable summers. All of these adaptations are co-ordinated. For example, cold hardiness relies on physiological and biochemical adaptations but also on habitat choice and timing. Because the adaptations are complex, predicted climatic warming probably will have unexpected effects. In particular, an increase in temperature that increases summer cloud when sea ice melts would likely reduce temperatures for insect development and activity, because sunshine provides critical warmth to insects and their microhabitats. Changes in moisture will also be important. Moreover, responses differ among species, depending especially on their microhabitats. The complexity of the responses of insects to arctic conditions reinforces the need for research that is sufficiently detailed.

  19. Thermal adaptation and ecological speciation.

    PubMed

    Keller, I; Seehausen, O

    2012-02-01

    Ecological speciation is defined as the emergence of reproductive isolation as a direct or indirect consequence of divergent ecological adaptation. Several empirical examples of ecological speciation have been reported in the literature which very often involve adaptation to biotic resources. In this review, we investigate whether adaptation to different thermal habitats could also promote speciation and try to assess the importance of such processes in nature. Our survey of the literature identified 16 animal and plant systems where divergent thermal adaptation may underlie (partial) reproductive isolation between populations or may allow the stable coexistence of sibling taxa. In many of the systems, the differentially adapted populations have a parapatric distribution along an environmental gradient. Isolation often involves extrinsic selection against locally maladapted parental or hybrid genotypes, and additional pre- or postzygotic barriers may be important. Together, the identified examples strongly suggest that divergent selection between thermal environments is often strong enough to maintain a bimodal genotype distribution upon secondary contact. What is less clear from the available data is whether it can also be strong enough to allow ecological speciation in the face of gene flow through reinforcement-like processes. It is possible that intrinsic features of thermal gradients or the genetic basis of thermal adaptation make such reinforcement-like processes unlikely but it is equally possible that pertinent systems are understudied. Overall, our literature survey highlights (once again) the dearth of studies that investigate similar incipient species along the continuum from initial divergence to full reproductive isolation and studies that investigate all possible reproductive barriers in a given system.

  20. Adaptation to blurred and sharpened video

    PubMed Central

    Haun, Andrew M.; Peli, Eli

    2013-01-01

    The visual system can distinguish different levels of blur and different levels of excess sharpness. Adaptation alters this capacity so that the adapted blur (or sharp) level looks more like a normal, properly focused image. Here, we describe the more general pattern of aftereffects of blur and sharp adaptation by measuring matching functions, using video clips from a DVD movie as stimuli. Results show that blur and sharp adaptation are selective: The sharpening aftereffects of blur adaptation are strongest for blurry videos while the blurring aftereffects of sharp adaptation are strongest for sharp videos. Despite the spatiotemporal variability of our adaptor and test stimuli, we found adaptation effects similar in magnitude to previous studies using invariant static images. A recent model of blur adaptation can be simplified to explain the form of our data, leading us to conclude that what we see as blur/sharp adaptation is a consequence of narrowband contrast adaptation. PMID:23857949

  1. Balthazar Scales of Adaptive Behavior: II. Scales of Social Adaption.

    ERIC Educational Resources Information Center

    Balthazar, Earl E.

    The Balthazar Scales of Adaptive Behavior II (BSAB-II) provides a system for program development and evaluation and for social behavior assessment of profoundly and severely mentally retarded individuals as well as of the younger less retarded and emotionally disturbed individuals. The specimen set consists of six parts: a Manual, a Tally Sheet…

  2. Digital adaptation algorithms of adaptive optics corrected images

    NASA Astrophysics Data System (ADS)

    Polskikh, Sergey D.; Sviridov, Konstantin N.

    2000-07-01

    The technology is considered of space object image obtainment with high angular resolution, based on the adaptive tuning of image spatial spectra (digital adaptation), corrected by adaptive optics. As the basis of the technology, the algorithm is taken of the integral equation of the I-st kind of convolution type with unknown core and imprecisely given right part. It's shown the procedure of the inverse operator construction for this equation solution is connected with minimization of nonlinear regularizing multiextremel functionals and could be realized on the base of global optimization methods. The structure of multiextremel functionals is analyzed, and the main global extremum search methods are researched. It is shown, that as the basis of the optimal construction of the channel for the obtainment of images with high resolution, the principle must be taken of the sequential reduction of the global extremum search space dimensionality, and what's more, the predetector processing of the wavefront by the adaptive optics is the first stage of this reduction. The results are given of numerical modelling including the examples of the distorted and restorated images of model objects under different signal-to-noise ratios.

  3. Adapting Books: Ready, Set, Read!: EAT: Equipment, Adaptations, and Technology

    ERIC Educational Resources Information Center

    Schoonover, Judith; Norton-Darr, Sally

    2016-01-01

    Developing multimodal materials to introduce or extend literacy experiences sets the stage for literacy success. Alternative ways to organize, display and arrange, interact and respond to information produces greater understanding of concepts. Adaptations include making books easier to use (turning pages or holding), and text easier to read…

  4. Adapting Books: Ready, Set, Read!: EAT: Equipment, Adaptations, and Technology

    ERIC Educational Resources Information Center

    Schoonover, Judith; Norton-Darr, Sally

    2016-01-01

    Developing multimodal materials to introduce or extend literacy experiences sets the stage for literacy success. Alternative ways to organize, display and arrange, interact and respond to information produces greater understanding of concepts. Adaptations include making books easier to use (turning pages or holding), and text easier to read…

  5. Brucella evasion of adaptive immunity.

    PubMed

    Martirosyan, Anna; Gorvel, Jean-Pierre

    2013-02-01

    The complex immune system of mammals is the result of evolutionary forces that include battles against pathogens, as sensing and defeating intruders is a prerequisite to host survival. On the other hand, microorganisms have evolved multiple mechanisms to evade both arms of immunity: the innate and the adaptive immune systems. The successful pathogenic intracellular bacterium Brucella is not an exception to the rule: Brucella displays mechanisms that allow evasion of immune surveillance in order to establish persistent infections in mammals. In this review, we highlight some key mechanisms that pathogenic Brucella use to evade the adaptive immune system.

  6. Model of aircraft noise adaptation

    NASA Technical Reports Server (NTRS)

    Dempsey, T. K.; Coates, G. D.; Cawthorn, J. M.

    1977-01-01

    Development of an aircraft noise adaptation model, which would account for much of the variability in the responses of subjects participating in human response to noise experiments, was studied. A description of the model development is presented. The principal concept of the model, was the determination of an aircraft adaptation level which represents an annoyance calibration for each individual. Results showed a direct correlation between noise level of the stimuli and annoyance reactions. Attitude-personality variables were found to account for varying annoyance judgements.

  7. Trichinella spiralis: Adaptation and parasitism.

    PubMed

    Zarlenga, Dante; Wang, Zhengyuan; Mitreva, Makedonka

    2016-11-15

    Publication of the genome from the clade I organism, Trichinella spiralis, has provided us an avenue to address more holistic problems in parasitology; namely the processes of adaptation and the evolution of parasitism. Parasitism among nematodes has evolved in multiple, independent events. Deciphering processes that drive species diversity and adaptation are keys to understanding parasitism and advancing control strategies. Studies have been put forth on morphological and physiological aspects of parasitism and adaptation in nematodes; however, data is now coming available to investigate adaptation, host switching and parasitism at the genomic level. Herein we compare proteomic data from the clade I parasite, Trichinella spiralis with data from Brugia malayi (clade III), Meloidogyne hapla and Meloidogyne incognita (clade IV), and free-living nematodes belonging to the genera Caenorhabditis and Pristionchus (clade V). We explore changes in protein family birth/death and expansion/reduction over the course of metazoan evolution using Homo sapiens, Drosophila melanogaster and Saccharomyces cerevisiae as outgroups for the phylum Nematoda. We further examine relationships between these changes and the ability and/or result of nematodes adapting to their environments. Data are consistent with gene loss occurring in conjunction with nematode specialization resulting from parasitic worms acclimating to well-defined, environmental niches. We observed evidence for independent, lateral gene transfer events involving conserved genes that may have played a role in the evolution of nematode parasitism. In general, parasitic nematodes gained proteins through duplication and lateral gene transfer, and lost proteins through random mutation and deletions. Data suggest independent acquisition rather than ancestral inheritance among the Nematoda followed by selective gene loss over evolutionary time. Data also show that parasitism and adaptation affected a broad range of proteins

  8. Adaptive dispersion in vowel perception.

    PubMed

    Johnson, K

    2000-01-01

    The 'hyperspace effect' in vowel perception may be taken as evidence that adaptive dispersion is an active perceptual process. However, a previous study tested for adaptive dispersion in isolated vowel stimuli spoken in a voice unfamiliar to the listeners. The experiment reported in this paper addressed both of these potential concerns and found that both consonant context and talker familiarity modulate the hyperspace effect. However, the reductions induced by context and familiarity were slight. Listeners' preferred perceptual spaces remained hyperarticulated relative to the production vowel space. Copyright 2000 S. Karger AG, Basel

  9. Religious groups as adaptive units.

    PubMed

    Wilson, D S

    2001-01-01

    This essay provides a sketch of religion as a set of biologically and culturally evolved adaptations that enable human groups to function as adaptive units. Recent developments in evolutionary biology make such a group-level interpretation of religion more plausible than in the past. A brief survey of relevant concepts is followed by a relatively detailed interpretation of Calvinism as a religious system in which explicit behavioral prescriptions, beliefs about God and his relationship with people, and numerous social control mechanisms combined to change the city of Geneva from a collection of warring factions to a unified population.

  10. Adaptive Optics Metrics & QC Scheme

    NASA Astrophysics Data System (ADS)

    Girard, Julien H.

    2017-09-01

    "There are many Adaptive Optics (AO) fed instruments on Paranal and more to come. To monitor their performances and assess the quality of the scientific data, we have developed a scheme and a set of tools and metrics adapted to each flavour of AO and each data product. Our decisions to repeat observations or not depends heavily on this immediate quality control "zero" (QC0). Atmospheric parameters monitoring can also help predict performances . At the end of the chain, the user must be able to find the data that correspond to his/her needs. In Particular, we address the special case of SPHERE."

  11. Seamless Resource-Adaptive Navigation

    NASA Astrophysics Data System (ADS)

    Schwartz, Tim; Stahl, Christoph; Baus, Jörg; Wahlster, Wolfgang

    Research in the project RENA (REsource-Adapative NAvigation) together with DFKI GmbH, BMW Research and Technology AG, and Eyeled GmbH has been concerned with the conceptual and methodological foundations and the design of a resource-adaptive platform for seamless outdoor and indoor navigation that can serve as a basis for product development by the companies in the RENA consortium. Future in-car assistance systems will have a user interface, which adapts to the driveŕs current exposure caused by the actual traffic situation.

  12. Adaptive Beamforming with Inadequate Snapshots

    NASA Astrophysics Data System (ADS)

    YU, Jing; LI, Yaan

    2017-01-01

    In array signal processing, the covariance matrix used to calculate the adaptive weights is often poor estimated when the snapshot number is inadequate. The prior environmental knowledge can be used to make the estimation more accuracy. In this paper, an alternative knowledge-aided adaptive beamforming approach that is robust to low sample support environment is proposed. In this algorithm the covariance matrix used to calculate the optimum weights is constructed by blending a sample covariance matrix and a priori structured covariance matrix. Numerical simulations demonstrate the proposed algorithm has the potential for substantial performance improvement.

  13. Chromatic adaptation of photosynthetic membranes.

    PubMed

    Scheuring, Simon; Sturgis, James N

    2005-07-15

    Many biological membranes adapt in response to environmental conditions. We investigated how the composition and architecture of photosynthetic membranes of a bacterium change in response to light, using atomic force microscopy. Despite large modifications in the membrane composition, the local environment of core complexes remained unaltered, whereas specialized paracrystalline light-harvesting antenna domains grew under low-light conditions. Thus, the protein mixture in the membrane shows eutectic behavior and can be mimicked by a simple model. Such structural adaptation ensures efficient photon capture under low-light conditions and prevents photodamage under high-light conditions.

  14. Autophagy, Immunity, and Microbial Adaptations

    PubMed Central

    Deretic, Vojo; Levine, Beth

    2009-01-01

    Autophagy adjusts cellular biomass and function in response to diverse stimuli, including infection. Autophagy plays specific roles in shaping immune system development, fueling host innate and adaptive immune responses, and directly controlling intracellular microbes as a cell-autonomous innate defense. As an evolutionary counterpoint, intracellular pathogens have evolved to block autophagic microbicidal defense and subvert host autophagic responses for their survival or growth. The ability of eukaryotic pathogens to deploy their own autophagic machinery may also contribute to microbial pathogenesis. Thus, a complex interplay between autophagy and microbial adaptations against autophagy governs the net outcome of host-microbe encounters. PMID:19527881

  15. Adaptive immunity in the liver.

    PubMed

    Shuai, Zongwen; Leung, Miranda Wy; He, Xiaosong; Zhang, Weici; Yang, Guoxiang; Leung, Patrick Sc; Eric Gershwin, M

    2016-05-01

    The anatomical architecture of the human liver and the diversity of its immune components endow the liver with its physiological function of immune competence. Adaptive immunity is a major arm of the immune system that is organized in a highly specialized and systematic manner, thus providing long-lasting protection with immunological memory. Adaptive immunity consists of humoral immunity and cellular immunity. Cellular immunity is known to have a crucial role in controlling infection, cancer and autoimmune disorders in the liver. In this article, we will focus on hepatic virus infections, hepatocellular carcinoma and autoimmune disorders as examples to illustrate the current understanding of the contribution of T cells to cellular immunity in these maladies. Cellular immune suppression is primarily responsible for chronic viral infections and cancer. However, an uncontrolled auto-reactive immune response accounts for autoimmunity. Consequently, these immune abnormalities are ascribed to the quantitative and functional changes in adaptive immune cells and their subsets, innate immunocytes, chemokines, cytokines and various surface receptors on immune cells. A greater understanding of the complex orchestration of the hepatic adaptive immune regulators during homeostasis and immune competence are much needed to identify relevant targets for clinical intervention to treat immunological disorders in the liver.

  16. Adaptive Identification by Systolic Arrays.

    DTIC Science & Technology

    1987-12-01

    BIBLIOGRIAPHY Anton , Howard , Elementary Linear Algebra , John Wiley & Sons, 19S4. Cristi, Roberto, A Parallel Structure Jor Adaptive Pole Placement...10 11. SYSTEM IDENTIFICATION M*YETHODS ....................... 12 A. LINEAR SYSTEM MODELING ......................... 12 B. SOLUTION OF SYSTEMS OF... LINEAR EQUATIONS ......... 13 C. QR DECOMPOSITION ................................ 14 D. RECURSIVE LEAST SQUARES ......................... 16 E. BLOCK

  17. Coastal Adaptation and Ecological Engineering

    NASA Astrophysics Data System (ADS)

    Cheong, S. M.

    2014-12-01

    Ecological engineering combines ecology and engineering to sustain coastal environment and facilitate adaptation to climate change. This paper discusses how the cases of mangroves, oyster reefs, and marshes help mainstream climate change with ecosystem conservation. It demonstrates the benefits of combining strategies to combat changing climate given the financial and political constraints.

  18. The sources of adaptive variation

    PubMed Central

    2017-01-01

    The role of natural selection in the evolution of adaptive phenotypes has undergone constant probing by evolutionary biologists, employing both theoretical and empirical approaches. As Darwin noted, natural selection can act together with other processes, including random changes in the frequencies of phenotypic differences that are not under strong selection, and changes in the environment, which may reflect evolutionary changes in the organisms themselves. As understanding of genetics developed after 1900, the new genetic discoveries were incorporated into evolutionary biology. The resulting general principles were summarized by Julian Huxley in his 1942 book Evolution: the modern synthesis. Here, we examine how recent advances in genetics, developmental biology and molecular biology, including epigenetics, relate to today's understanding of the evolution of adaptations. We illustrate how careful genetic studies have repeatedly shown that apparently puzzling results in a wide diversity of organisms involve processes that are consistent with neo-Darwinism. They do not support important roles in adaptation for processes such as directed mutation or the inheritance of acquired characters, and therefore no radical revision of our understanding of the mechanism of adaptive evolution is needed. PMID:28566483

  19. Adapting for Students with Autism

    ERIC Educational Resources Information Center

    Darrow, Alice-Ann

    2009-01-01

    Autism is the most common condition in a group of developmental disorders known as the autism spectrum disorders (ASDs). Although autism is considered a low-incidence disorder, many music educators in schools today teach students with autism each week. Students with ASDs usually require similar educational interventions that are adapted to their…

  20. Adaptive immunity in the liver

    PubMed Central

    Shuai, Zongwen; Leung, Miranda WY; He, Xiaosong; Zhang, Weici; Yang, Guoxiang; Leung, Patrick SC; Eric Gershwin, M

    2016-01-01

    The anatomical architecture of the human liver and the diversity of its immune components endow the liver with its physiological function of immune competence. Adaptive immunity is a major arm of the immune system that is organized in a highly specialized and systematic manner, thus providing long-lasting protection with immunological memory. Adaptive immunity consists of humoral immunity and cellular immunity. Cellular immunity is known to have a crucial role in controlling infection, cancer and autoimmune disorders in the liver. In this article, we will focus on hepatic virus infections, hepatocellular carcinoma and autoimmune disorders as examples to illustrate the current understanding of the contribution of T cells to cellular immunity in these maladies. Cellular immune suppression is primarily responsible for chronic viral infections and cancer. However, an uncontrolled auto-reactive immune response accounts for autoimmunity. Consequently, these immune abnormalities are ascribed to the quantitative and functional changes in adaptive immune cells and their subsets, innate immunocytes, chemokines, cytokines and various surface receptors on immune cells. A greater understanding of the complex orchestration of the hepatic adaptive immune regulators during homeostasis and immune competence are much needed to identify relevant targets for clinical intervention to treat immunological disorders in the liver. PMID:26996069

  1. Interoperability in Personalized Adaptive Learning

    ERIC Educational Resources Information Center

    Aroyo, Lora; Dolog, Peter; Houben, Geert-Jan; Kravcik, Milos; Naeve, Ambjorn; Nilsson, Mikael; Wild, Fridolin

    2006-01-01

    Personalized adaptive learning requires semantic-based and context-aware systems to manage the Web knowledge efficiently as well as to achieve semantic interoperability between heterogeneous information resources and services. The technological and conceptual differences can be bridged either by means of standards or via approaches based on the…

  2. School Adaptation of Roma Children

    ERIC Educational Resources Information Center

    Gerganov, Encho; Varbanova, Silvia; Kyuchukov, Hristo

    2005-01-01

    This paper examines the degree of school adaptation among Roma children who were included in a program for the desegregation of Roma schools in Bulgaria. More specifically, the program requires Roma children to attend mixed classes with Bulgarian students and Roma teacher assistants to work with them. The Bulgarian version of the Questionnaire on…

  3. Climate Adaptation of Tropical Cattle.

    PubMed

    Barendse, W

    2017-02-08

    There is sustained growth in the number of tropical cattle, which represent more than half of all cattle worldwide. By and large, most research in tropical areas is still focused on breeds of cattle, their particular advantages or disadvantages in tropical areas, and the tropical forages or feeds that could be usefully fed to them. A consistent issue for adaptation to climate is the heat of tropical environments. Changing the external characteristics of the animal, such as color and coat characteristics, is one way to adapt, and there are several major genes for these traits. However, further improvement in heat tolerance and other adaptation traits will need to use the entire genome and all physical and physiological systems. Apart from the response to heat, climate forcing through methane emission identifies dry season weight loss as an important if somewhat neglected trait in climate adaptation of cattle. The use of genome-estimated breeding values in tropical areas is in its infancy and will be difficult to implement, but will be essential for rapid, coordinated genetic improvement. The difficulty of implementation cannot be exaggerated and may require major improvements in methodology.

  4. Adapted Minds and Evolved Schools

    ERIC Educational Resources Information Center

    Keil, Frank C.

    2008-01-01

    Evolutionary psychology raises questions about how cognitive adaptations might be related to the emergence of formal schooling. Is there a special role for natural domains of cognition such as folk physics, folk psychology and folk biology? These domains may vary from small fragments of reasoning to large integrated systems. This heterogeneity…

  5. Adaptive Devices and the Computer.

    ERIC Educational Resources Information Center

    Taber, Florence M.

    1986-01-01

    Guidelines for selecting appropriate assistive devices which afford disabled individuals access to computers are presented. In general, the individual who is to use the computer must be evaluated first to ensure that the adaptive device makes the most efficient use of his/her muscle control, mobility, reflexes, etc. (CB)

  6. Generalized Adaptive Artificial Neural Networks

    NASA Technical Reports Server (NTRS)

    Tawel, Raoul

    1993-01-01

    Mathematical model of supervised learning by artificial neural network provides for simultaneous adjustments of both temperatures of neurons and synaptic weights, and includes feedback as well as feedforward synaptic connections. Extension of mathematical model described in "Adaptive Neurons For Artificial Neural Networks" (NPO-17803). Dynamics of neural network represented in new model by less-restrictive continuous formalism.

  7. Perceptual Fading without Retinal Adaptation

    ERIC Educational Resources Information Center

    Hsieh, Po-Jang; Colas, Jaron T.

    2012-01-01

    A retinally stabilized object readily undergoes perceptual fading and disappears from consciousness. This startling phenomenon is commonly believed to arise from local bottom-up sensory adaptation to edge information that occurs early in the visual pathway, such as in the lateral geniculate nucleus of the thalamus or retinal ganglion cells. Here…

  8. Adaptive Devices and the Computer.

    ERIC Educational Resources Information Center

    Taber, Florence M.

    1986-01-01

    Guidelines for selecting appropriate assistive devices which afford disabled individuals access to computers are presented. In general, the individual who is to use the computer must be evaluated first to ensure that the adaptive device makes the most efficient use of his/her muscle control, mobility, reflexes, etc. (CB)

  9. Deleterious Passengers in Adapting Populations

    PubMed Central

    Good, Benjamin H.; Desai, Michael M.

    2014-01-01

    Most new mutations are deleterious and are eventually eliminated by natural selection. But in an adapting population, the rapid amplification of beneficial mutations can hinder the removal of deleterious variants in nearby regions of the genome, altering the patterns of sequence evolution. Here, we analyze the interactions between beneficial “driver” mutations and linked deleterious “passengers” during the course of adaptation. We derive analytical expressions for the substitution rate of a deleterious mutation as a function of its fitness cost, as well as the reduction in the beneficial substitution rate due to the genetic load of the passengers. We find that the fate of each deleterious mutation varies dramatically with the rate and spectrum of beneficial mutations and the deleterious substitution rate depends nonmonotonically on the population size and the rate of adaptation. By quantifying this dependence, our results allow us to estimate which deleterious mutations will be likely to fix and how many of these mutations must arise before the progress of adaptation is significantly reduced. PMID:25194161

  10. Adaptive protection algorithm and system

    DOEpatents

    Hedrick, Paul [Pittsburgh, PA; Toms, Helen L [Irwin, PA; Miller, Roger M [Mars, PA

    2009-04-28

    An adaptive protection algorithm and system for protecting electrical distribution systems traces the flow of power through a distribution system, assigns a value (or rank) to each circuit breaker in the system and then determines the appropriate trip set points based on the assigned rank.

  11. Directed evolution of adaptive traits

    USDA-ARS?s Scientific Manuscript database

    As a species, switchgrass is adapted to an amazingly broad range of environments, spanning hardiness zones ranging from HZ3 to HZ9 (Canada to Mexico), from the mid-grass prairie to the Atlantic Seaboard, from sandy soils to heavy clay soils, from acid to alkaline soils, and from wetland to dryland h...

  12. Adapting for Students with Autism

    ERIC Educational Resources Information Center

    Darrow, Alice-Ann

    2009-01-01

    Autism is the most common condition in a group of developmental disorders known as the autism spectrum disorders (ASDs). Although autism is considered a low-incidence disorder, many music educators in schools today teach students with autism each week. Students with ASDs usually require similar educational interventions that are adapted to their…

  13. Agricultural Adaptation to Climate Change

    NASA Astrophysics Data System (ADS)

    Tam, A.; Jain, M.

    2016-12-01

    This research includes two projects pertaining to agricultural systems' adaption to climate change. The first research project focuses on the wheat yielding regions of India. Wheat is a major staple crop and many rural households and smallholder farmers rely on crop yields for survival. We examine the impacts of weather variability and groundwater depletion on agricultural systems, using geospatial analysis and satellite-based analysis and household-based and census data sets. We use these methods to estimate the crop yields and identify what factors are associated with low versus high yielding regions. This can help identify strategies that should be further promoted to increase crop yields. The second research project is a literature review. We conduct a meta-analysis and synthetic review on literature about agricultural adaptation to climate change. We sort through numerous articles to identify and examine articles that associate socio-economic, biophysical, and perceptional factors to farmers' adaption to climate change. Our preliminary results show that researchers tend to associate few factors to a farmers' vulnerability and adaptive capacity, and most of the research conducted is concentrated in North America, whereas tropical regions that are highly vulnerable to weather variability are underrepresented by literature. There are no conclusive results in both research projects as of so far.

  14. Organization of Distributed Adaptive Learning

    ERIC Educational Resources Information Center

    Vengerov, Alexander

    2009-01-01

    The growing sensitivity of various systems and parts of industry, society, and even everyday individual life leads to the increased volume of changes and needs for adaptation and learning. This creates a new situation where learning from being purely academic knowledge transfer procedure is becoming a ubiquitous always-on essential part of all…

  15. The Adaptation of Migrant Children

    ERIC Educational Resources Information Center

    Portes, Alejandro; Rivas, Alejandro

    2011-01-01

    Alejandro Portes and Alejandro Rivas examine how young immigrants are adapting to life in the United States. They begin by noting the existence of two distinct pan-ethnic populations: Asian Americans, who tend to be the offspring of high-human-capital migrants, and Hispanics, many of whose parents are manual workers. Vast differences in each, both…

  16. Phenotypic heterogeneity promotes adaptive evolution

    PubMed Central

    Nevozhay, Dmitry; Kalapis, Dorottya; Lázár, Viktória; Csörgő, Bálint; Nyerges, Ákos; Szamecz, Béla; Fekete, Gergely; Papp, Balázs; Araújo, Hugo; Oliveira, José L.; Moura, Gabriela; Santos, Manuel A. S.; Székely Jr, Tamás; Balázsi, Gábor

    2017-01-01

    Genetically identical cells frequently display substantial heterogeneity in gene expression, cellular morphology and physiology. It has been suggested that by rapidly generating a subpopulation with novel phenotypic traits, phenotypic heterogeneity (or plasticity) accelerates the rate of adaptive evolution in populations facing extreme environmental challenges. This issue is important as cell-to-cell phenotypic heterogeneity may initiate key steps in microbial evolution of drug resistance and cancer progression. Here, we study how stochastic transitions between cellular states influence evolutionary adaptation to a stressful environment in yeast Saccharomyces cerevisiae. We developed inducible synthetic gene circuits that generate varying degrees of expression stochasticity of an antifungal resistance gene. We initiated laboratory evolutionary experiments with genotypes carrying different versions of the genetic circuit by exposing the corresponding populations to gradually increasing antifungal stress. Phenotypic heterogeneity altered the evolutionary dynamics by transforming the adaptive landscape that relates genotype to fitness. Specifically, it enhanced the adaptive value of beneficial mutations through synergism between cell-to-cell variability and genetic variation. Our work demonstrates that phenotypic heterogeneity is an evolving trait when populations face a chronic selection pressure. It shapes evolutionary trajectories at the genomic level and facilitates evolutionary rescue from a deteriorating environmental stress. PMID:28486496

  17. The Adaptive Kernel Neural Network

    DTIC Science & Technology

    1989-10-01

    A neural network architecture for clustering and classification is described. The Adaptive Kernel Neural Network (AKNN) is a density estimation...classification layer. The AKNN retains the inherent parallelism common in neural network models. Its relationship to the kernel estimator allows the network to

  18. Adaptive Testing without a Computer.

    DTIC Science & Technology

    1981-03-01

    tests to examinees. As early as the beginninq of the twentieth century, Alfred Binet (see Peterson, 1926) developed adaptive tests for educational...screening. The success of the group-administered tests dveiop’, du riq the first World War, cnupled with the long administration time of the Binet tests

  19. Strategies of Adaptive Ability Measurement.

    ERIC Educational Resources Information Center

    Weiss, David J.

    A number of strategies are described for adapting ability test items to individual differences in ability levels of testees. Each strategy consists of a different set of rules for selecting the sequence of test items to be administered to a given testee. Advantages and disadvantages of each strategy are discussed, and research issues unique to the…

  20. Adaptive evolution of Mediterranean pines.

    PubMed

    Grivet, Delphine; Climent, José; Zabal-Aguirre, Mario; Neale, David B; Vendramin, Giovanni G; González-Martínez, Santiago C

    2013-09-01

    Mediterranean pines represent an extremely heterogeneous assembly. Although they have evolved under similar environmental conditions, they diversified long ago, ca. 10 Mya, and present distinct biogeographic and demographic histories. Therefore, it is of special interest to understand whether and to what extent they have developed specific strategies of adaptive evolution through time and space. To explore evolutionary patterns, the Mediterranean pines' phylogeny was first reconstructed analyzing a new set of 21 low-copy nuclear genes with multilocus Bayesian tree reconstruction methods. Secondly, a phylogenetic approach was used to search for footprints of natural selection and to examine the evolution of multiple phenotypic traits. We identified two genes (involved in pines' defense and stress responses) that have likely played a role in the adaptation of Mediterranean pines to their environment. Moreover, few life-history traits showed historical or evolutionary adaptive convergence in Mediterranean lineages, while patterns of character evolution revealed various evolutionary trade-offs linking growth-development, reproduction and fire-related traits. Assessing the evolutionary path of important life-history traits, as well as the genomic basis of adaptive variation is central to understanding the past evolutionary success of Mediterranean pines and their future response to environmental changes.

  1. Adaptive Clustering of Hypermedia Documents.

    ERIC Educational Resources Information Center

    Johnson, Andrew; Fotouhi, Farshad

    1996-01-01

    Discussion of hypermedia systems focuses on a comparison of two types of adaptive algorithm (genetic algorithm and neural network) in clustering hypermedia documents. These clusters allow the user to index into the nodes to find needed information more quickly, since clustering is "personalized" based on the user's paths rather than…

  2. Candida albicans: adapting to succeed.

    PubMed

    Kadosh, David; Lopez-Ribot, Jose L

    2013-11-13

    In this issue of Cell Host & Microbe, Lu et al. (2013) report on the redundancy of signaling pathways controlling Candida albicans filamentation and pathogenicity. In the process, they provide important insight into how this normal commensal of humans adapts to different host microenvironments to become a highly successful opportunistic pathogen.

  3. Human whole body cold adaptation

    PubMed Central

    Daanen, Hein A.M.; Van Marken Lichtenbelt, Wouter D.

    2016-01-01

    ABSTRACT Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold. PMID:27227100

  4. Optimal Transport for Domain Adaptation.

    PubMed

    Courty, Nicolas; Flamary, Remi; Tuia, Devis; Rakotomamonjy, Alain

    2017-09-01

    Domain adaptation is one of the most challenging tasks of modern data analytics. If the adaptation is done correctly, models built on a specific data representation become more robust when confronted to data depicting the same classes, but described by another observation system. Among the many strategies proposed, finding domain-invariant representations has shown excellent properties, in particular since it allows to train a unique classifier effective in all domains. In this paper, we propose a regularized unsupervised optimal transportation model to perform the alignment of the representations in the source and target domains. We learn a transportation plan matching both PDFs, which constrains labeled samples of the same class in the source domain to remain close during transport. This way, we exploit at the same time the labeled samples in the source and the distributions observed in both domains. Experiments on toy and challenging real visual adaptation examples show the interest of the method, that consistently outperforms state of the art approaches. In addition, numerical experiments show that our approach leads to better performances on domain invariant deep learning features and can be easily adapted to the semi-supervised case where few labeled samples are available in the target domain.

  5. Shaker slip-plate adapter

    NASA Technical Reports Server (NTRS)

    Holm, O. S.

    1969-01-01

    Magnesium adapter ties in all of the attachment bosses on a horizontal slip table and makes a rigid coupling which terminates in a single row of attachment bosses at the edge of the horizontal plate. This eliminates ineffective dissipation of the driving force in vibration tests.

  6. Interoperability in Personalized Adaptive Learning

    ERIC Educational Resources Information Center

    Aroyo, Lora; Dolog, Peter; Houben, Geert-Jan; Kravcik, Milos; Naeve, Ambjorn; Nilsson, Mikael; Wild, Fridolin

    2006-01-01

    Personalized adaptive learning requires semantic-based and context-aware systems to manage the Web knowledge efficiently as well as to achieve semantic interoperability between heterogeneous information resources and services. The technological and conceptual differences can be bridged either by means of standards or via approaches based on the…

  7. Type Evolution and Instance Adaptation

    DTIC Science & Technology

    1992-06-01

    Schema evolution support is an important facility for object-oriented database (OODB) systems. While existing OODB systems provide for limited forms...of evolution , including modification to the database schema and reorganization of affected instances, we find their support insufficient. Specific... evolution of class definitions and the adaptation of existing, persistent instances to those new definitions.

  8. School Adaptation of Roma Children

    ERIC Educational Resources Information Center

    Gerganov, Encho; Varbanova, Silvia; Kyuchukov, Hristo

    2005-01-01

    This paper examines the degree of school adaptation among Roma children who were included in a program for the desegregation of Roma schools in Bulgaria. More specifically, the program requires Roma children to attend mixed classes with Bulgarian students and Roma teacher assistants to work with them. The Bulgarian version of the Questionnaire on…

  9. Cardiovascular Adaptations to Exercise Training.

    PubMed

    Hellsten, Ylva; Nyberg, Michael

    2015-12-15

    Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved contractility, and an increase in blood volume, allowing for greater filling of the ventricles and a consequent larger stroke volume. In parallel with the greater maximal cardiac output, the perfusion capacity of the muscle is increased, permitting for greater oxygen delivery. To accommodate the higher aerobic demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle allowing for an improved capacity for oxygen extraction by the muscle through a greater area for diffusion, a shorter diffusion distance, and a longer mean transit time for the erythrocyte to pass through the smallest blood vessels. The present article addresses the effect of endurance training on systemic and peripheral cardiovascular adaptations with a focus on humans, but also covers animal data.

  10. Adaptive Clustering of Hypermedia Documents.

    ERIC Educational Resources Information Center

    Johnson, Andrew; Fotouhi, Farshad

    1996-01-01

    Discussion of hypermedia systems focuses on a comparison of two types of adaptive algorithm (genetic algorithm and neural network) in clustering hypermedia documents. These clusters allow the user to index into the nodes to find needed information more quickly, since clustering is "personalized" based on the user's paths rather than…

  11. Curriculum Adaptation for Inclusive Classrooms.

    ERIC Educational Resources Information Center

    Neary, Tom; And Others

    This manual on curriculum adaptation for inclusive classrooms was developed as part of the PEERS (Providing Education for Everyone in Regular Schools) Project, a 5-year collaborative systems change project in California to facilitate the integration of students with severe disabilities previously at special centers into services at regular school…

  12. Reward Modulates Adaptations to Conflict

    ERIC Educational Resources Information Center

    Braem, Senne; Verguts, Tom; Roggeman, Chantal; Notebaert, Wim

    2012-01-01

    Both cognitive conflict (e.g. Verguts & Notebaert, 2009) and reward signals (e.g. Waszak & Pholulamdeth, 2009) have been proposed to enhance task-relevant associations. Bringing these two notions together, we predicted that reward modulates conflict-based sequential adaptations in cognitive control. This was tested combining either a single…

  13. Adapted Minds and Evolved Schools

    ERIC Educational Resources Information Center

    Keil, Frank C.

    2008-01-01

    Evolutionary psychology raises questions about how cognitive adaptations might be related to the emergence of formal schooling. Is there a special role for natural domains of cognition such as folk physics, folk psychology and folk biology? These domains may vary from small fragments of reasoning to large integrated systems. This heterogeneity…

  14. Adaptive wiener image restoration kernel

    DOEpatents

    Yuan, Ding

    2007-06-05

    A method and device for restoration of electro-optical image data using an adaptive Wiener filter begins with constructing imaging system Optical Transfer Function, and the Fourier Transformations of the noise and the image. A spatial representation of the imaged object is restored by spatial convolution of the image using a Wiener restoration kernel.

  15. Adaptive Control Of Remote Manipulator

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun

    1989-01-01

    Robotic control system causes remote manipulator to follow closely reference trajectory in Cartesian reference frame in work space, without resort to computationally intensive mathematical model of robot dynamics and without knowledge of robot and load parameters. System, derived from linear multivariable theory, uses relatively simple feedforward and feedback controllers with model-reference adaptive control.

  16. Reward Modulates Adaptations to Conflict

    ERIC Educational Resources Information Center

    Braem, Senne; Verguts, Tom; Roggeman, Chantal; Notebaert, Wim

    2012-01-01

    Both cognitive conflict (e.g. Verguts & Notebaert, 2009) and reward signals (e.g. Waszak & Pholulamdeth, 2009) have been proposed to enhance task-relevant associations. Bringing these two notions together, we predicted that reward modulates conflict-based sequential adaptations in cognitive control. This was tested combining either a single…

  17. Making Pedagogical Adaptability Less Obvious

    ERIC Educational Resources Information Center

    Vagle, Mark D.

    2016-01-01

    In this article, I try to make pedagogical adaptability a bit less obvious. In particular, I use some post-structural philosophical ideas and some concepts at the intersections of social class and race to re-interpret Dylan Wiliam's conception of formative assessment. I suggest that this interpretation can provide opportunities to resist the urge…

  18. Generalized Adaptive Artificial Neural Networks

    NASA Technical Reports Server (NTRS)

    Tawel, Raoul

    1993-01-01

    Mathematical model of supervised learning by artificial neural network provides for simultaneous adjustments of both temperatures of neurons and synaptic weights, and includes feedback as well as feedforward synaptic connections. Extension of mathematical model described in "Adaptive Neurons For Artificial Neural Networks" (NPO-17803). Dynamics of neural network represented in new model by less-restrictive continuous formalism.

  19. ADAPTIVE EYE MODEL - Poster Paper

    NASA Astrophysics Data System (ADS)

    Galetskiy, Sergey O.; Kudryashov, Alexey V.

    2008-01-01

    We propose experimental adaptive eye model based on flexible 18-electrode bimorph mirror reproducing human eye aberrations up to 4th radial order of Zernike polynomials at frequency of 10Hz. The accuracy of aberrations reproduction in most cases is better than λ/10 RMS. The model is introduced to aberrometer for human eye aberrations compensation to improve visual acuity test.

  20. Perceptual Fading without Retinal Adaptation

    ERIC Educational Resources Information Center

    Hsieh, Po-Jang; Colas, Jaron T.

    2012-01-01

    A retinally stabilized object readily undergoes perceptual fading and disappears from consciousness. This startling phenomenon is commonly believed to arise from local bottom-up sensory adaptation to edge information that occurs early in the visual pathway, such as in the lateral geniculate nucleus of the thalamus or retinal ganglion cells. Here…

  1. Adaptive Controller Effects on Pilot Behavior

    NASA Technical Reports Server (NTRS)

    Trujillo, Anna C.; Gregory, Irene M.; Hempley, Lucas E.

    2014-01-01

    Adaptive control provides robustness and resilience for highly uncertain, and potentially unpredictable, flight dynamics characteristic. Some of the recent flight experiences of pilot-in-the-loop with an adaptive controller have exhibited unpredicted interactions. In retrospect, this is not surprising once it is realized that there are now two adaptive controllers interacting, the software adaptive control system and the pilot. An experiment was conducted to categorize these interactions on the pilot with an adaptive controller during control surface failures. One of the objectives of this experiment was to determine how the adaptation time of the controller affects pilots. The pitch and roll errors, and stick input increased for increasing adaptation time and during the segment when the adaptive controller was adapting. Not surprisingly, altitude, cross track and angle deviations, and vertical velocity also increase during the failure and then slowly return to pre-failure levels. Subjects may change their behavior even as an adaptive controller is adapting with additional stick inputs. Therefore, the adaptive controller should adapt as fast as possible to minimize flight track errors. This will minimize undesirable interactions between the pilot and the adaptive controller and maintain maneuvering precision.

  2. Data-Adaptable Modeling and Optimization for Runtime Adaptable Systems

    DTIC Science & Technology

    2016-06-08

    Adaptability-as-a-service for embedded real-time dataflow systems b. Captures semantic and programmatic composability by design DISTRIBUTION A: Distribution... embedded systems (DAES) requires new methodologies and tools to support both design and synthesis. In this paper, we introduce a modeling tool, called...K. Prasanna, and A. Ledeczi, 2001. “MILAN: A Model Based Integrated Simulation Framework for Design of Embedded Systems ,” In Proc. of the 2001 ACM

  3. Adapting to life: ocean biogeochemical modelling and adaptive remeshing

    NASA Astrophysics Data System (ADS)

    Hill, J.; Popova, E. E.; Ham, D. A.; Piggott, M. D.; Srokosz, M.

    2013-11-01

    An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. As an example, state-of-the-art models give values of primary production approximately two orders of magnitude lower than those observed in the ocean's oligotrophic gyres, which cover a third of the Earth's surface. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a~simple vertical column (quasi 1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The simulations capture both the seasonal and inter-annual variations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2-3, so reducing computational overhead. We then show the potential of this method in two case studies where we change the metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate adaptive meshes may provide a~suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high spatial resolution whilst minimising

  4. Adaptive security systems -- Combining expert systems with adaptive technologies

    SciTech Connect

    Argo, P.; Loveland, R.; Anderson, K.

    1997-09-01

    The Adaptive Multisensor Integrated Security System (AMISS) uses a variety of computational intelligence techniques to reason from raw sensor data through an array of processing layers to arrive at an assessment for alarm/alert conditions based on human behavior within a secure facility. In this paper, the authors give an overview of the system and briefly describe some of the major components of the system. This system is currently under development and testing in a realistic facility setting.

  5. VISUAL ADAPTATION AND CHEMISTRY OF THE RODS

    PubMed Central

    Wald, George; Clark, Anna-Betty

    1937-01-01

    1. The reality of a chemical cycle proposed to describe the rhodopsin system is tested with dark adaptation measurements. 2. The first few minutes of rod dark adaptation are rapid following short, slower following long irradiation. As dark adaptation proceeds, the slow process grows more prominent, and occupies completely the final stages of adaptation. 3. Light adaptation displays similar duality. As the exposure to light of constant intensity lengthens, the visual threshold rises, and independently the speed of dark adaptation decreases. 4. These results conform with predictions from the chemical equations. PMID:19873041

  6. Operator adaptation to changes in system reliability under adaptable automation.

    PubMed

    Chavaillaz, Alain; Sauer, Juergen

    2016-11-25

    This experiment examined how operators coped with a change in system reliability between training and testing. Forty participants were trained for 3 h on a complex process control simulation modelling six levels of automation (LOA). In training, participants either experienced a high- (100%) or low-reliability system (50%). The impact of training experience on operator behaviour was examined during a 2.5 h testing session, in which participants either experienced a high- (100%) or low-reliability system (60%). The results showed that most operators did not often switch between LOA. Most chose an LOA that relieved them of most tasks but maintained their decision authority. Training experience did not have a strong impact on the outcome measures (e.g. performance, complacency). Low system reliability led to decreased performance and self-confidence. Furthermore, complacency was observed under high system reliability. Overall, the findings suggest benefits of adaptable automation because it accommodates different operator preferences for LOA. Practitioner Summary: The present research shows that operators can adapt to changes in system reliability between training and testing sessions. Furthermore, it provides evidence that each operator has his/her preferred automation level. Since this preference varies strongly between operators, adaptable automation seems to be suitable to accommodate these large differences.

  7. Nonuniform spatially adaptive wavelet packets

    NASA Astrophysics Data System (ADS)

    Carre, Philippe; Fernandez-Maloigne, Christine

    2000-12-01

    In this paper, we propose a new decomposition scheme for spatially adaptive wavelet packets. Contrary to the double tree algorithm, our method is non-uniform and shift- invariant in the time and frequency domains, and is minimal for an information cost function. We prose some-restrictions to our algorithm to reduce the complexity and permitting us to provide some time-frequency partitions of the signal in agreement with its structure. This new 'totally' non-uniform transform, more adapted than Malvar, Packets or dyadic double-tree decomposition, allows the study of all possible time-frequency partitions with the only restriction that the blocks are rectangular. It permits one to obtain a satisfying Time-Frequency representation, and is applied for the study of EEG signals.

  8. Passive adaptive imaging through turbulence

    NASA Astrophysics Data System (ADS)

    Tofsted, David

    2016-05-01

    Standard methods for improved imaging system performance under degrading optical turbulence conditions typically involve active adaptive techniques or post-capture image processing. Here, passive adaptive methods are considered where active sources are disallowed, a priori. Theoretical analyses of short-exposure turbulence impacts indicate that varying aperture sizes experience different degrees of turbulence impacts. Smaller apertures often outperform larger aperture systems as turbulence strength increases. This suggests a controllable aperture system is advantageous. In addition, sub-aperture sampling of a set of training images permits the system to sense tilts in different sub-aperture regions through image acquisition and image cross-correlation calculations. A four sub-aperture pattern supports corrections involving five realizable operating modes (beyond tip and tilt) for removing aberrations over an annular pattern. Progress to date will be discussed regarding development and field trials of a prototype system.

  9. Evolutionary Adaptations to Dietary Changes

    PubMed Central

    Luca, F.; Perry, G.H.; Di Rienzo, A.

    2014-01-01

    Through cultural innovation and changes in habitat and ecology, there have been a number of major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. The identification of signatures of adaptations to such dietary changes in the genome of extant primates (including humans) may shed light not only on the evolutionary history of our species, but also on the mechanisms that underlie common metabolic diseases in modern human populations. In this review, we provide a brief overview of the major dietary shifts that occurred during hominin evolution, and we discuss the methods and approaches used to identify signals of natural selection in patterns of sequence variation. We then review the results of studies aimed at detecting the genetic loci that played a major role in dietary adaptations and conclude by outlining the potential of future studies in this area. PMID:20420525

  10. Adaptation and irreversibility in microevolution

    NASA Astrophysics Data System (ADS)

    Bo, Stefano; Mazzolini, Andrea; Celani, Antonio

    2014-12-01

    Within the framework of population genetics we consider the evolution of an asexual haploid population under the effect of a rapidly varying natural selection (microevolution). We focus on the case in which the environment exerting selection changes stochastically. We derive the effective genotype and fitness dynamics on the slower timescales at which the relevant genetic modifications take place. We find that, despite the fast environmental switches, the population manages to adapt on the fast timescales yielding a finite positive contribution to the fitness. However, such contribution is balanced by the continuous loss in fitness due to the varying selection so that the statistics of the global fitness can be described neglecting the details of the fast environmental process. The occurrence of adaptation on fast timescales would be undetectable if one were to consider only the effective genotype and fitness dynamics on the slow timescales. We therefore propose an experimental observable to detect it.

  11. Plant adaptation to drought stress.

    PubMed

    Basu, Supratim; Ramegowda, Venkategowda; Kumar, Anuj; Pereira, Andy

    2016-01-01

    Plants in their natural habitats adapt to drought stress in the environment through a variety of mechanisms, ranging from transient responses to low soil moisture to major survival mechanisms of escape by early flowering in absence of seasonal rainfall. However, crop plants selected by humans to yield products such as grain, vegetable, or fruit in favorable environments with high inputs of water and fertilizer are expected to yield an economic product in response to inputs. Crop plants selected for their economic yield need to survive drought stress through mechanisms that maintain crop yield. Studies on model plants for their survival under stress do not, therefore, always translate to yield of crop plants under stress, and different aspects of drought stress response need to be emphasized. The crop plant model rice ( Oryza sativa) is used here as an example to highlight mechanisms and genes for adaptation of crop plants to drought stress.

  12. Adaptive Behavior for Mobile Robots

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terrance

    2009-01-01

    The term "System for Mobility and Access to Rough Terrain" (SMART) denotes a theoretical framework, a control architecture, and an algorithm that implements the framework and architecture, for enabling a land-mobile robot to adapt to changing conditions. SMART is intended to enable the robot to recognize adverse terrain conditions beyond its optimal operational envelope, and, in response, to intelligently reconfigure itself (e.g., adjust suspension heights or baseline distances between suspension points) or adapt its driving techniques (e.g., engage in a crabbing motion as a switchback technique for ascending steep terrain). Conceived for original application aboard Mars rovers and similar autonomous or semi-autonomous mobile robots used in exploration of remote planets, SMART could also be applied to autonomous terrestrial vehicles to be used for search, rescue, and/or exploration on rough terrain.

  13. Nanosatellite Launch Adapter System (NLAS)

    NASA Technical Reports Server (NTRS)

    Yost, Bruce D.; Hines, John W.; Agasid, Elwood F.; Buckley, Steven J.

    2010-01-01

    The utility of small spacecraft based on the University cubesat standard is becoming evident as more and more agencies and organizations are launching or planning to include nanosatellites in their mission portfolios. Cubesats are typically launched as secondary spacecraft in enclosed, containerized deployers such as the CalPoly Poly Picosat Orbital Deployer (P-POD) system. The P-POD allows for ease of integration and significantly reduces the risk exposure to the primary spacecraft and mission. NASA/ARC and the Operationally Responsive Space office are collaborating to develop a Nanosatellite Launch Adapter System (NLAS), which can accommodate multiple cubesat or cubesat-derived spacecraft on a single launch vehicle. NLAS is composed of the adapter structure, P-POD or similar spacecraft dispensers, and a sequencer/deployer system. This paper describes the NLAS system and it s future capabilities, and also provides status on the system s development and potential first use in space.

  14. Adaptive walk on complex networks.

    PubMed

    Campos, Paulo R A; Moreira, F G Brady

    2005-06-01

    We investigate the properties of adaptive walks on an uncorrelated fitness landscape which is established in sequence spaces of complex structure. In particular, we perform numerical simulations of adaptive walks on random graphs and scale-free networks. For the former, we also derive some analytical approximations for the density of local optima of the fitness landscape and the mean length walk. We compare our results with those obtained for regular lattices. We obtain that the density of local optima decreases as 1/z, where z is the mean connectivity, for all networks we have investigated. In random graphs, the mean length walk L reaches the asymptotic value e - 1 for large z, which corresponds to the result for regular networks. Although we could not find an exact estimate, we derive an underestimated value for L. Unlike random graphs, scale-free networks show an upper asymptotic value of L.

  15. Psychometrics behind Computerized Adaptive Testing.

    PubMed

    Chang, Hua-Hua

    2015-03-01

    The paper provides a survey of 18 years' progress that my colleagues, students (both former and current) and I made in a prominent research area in Psychometrics-Computerized Adaptive Testing (CAT). We start with a historical review of the establishment of a large sample foundation for CAT. It is worth noting that the asymptotic results were derived under the framework of Martingale Theory, a very theoretical perspective of Probability Theory, which may seem unrelated to educational and psychological testing. In addition, we address a number of issues that emerged from large scale implementation and show that how theoretical works can be helpful to solve the problems. Finally, we propose that CAT technology can be very useful to support individualized instruction on a mass scale. We show that even paper and pencil based tests can be made adaptive to support classroom teaching.

  16. Plant adaptation to drought stress

    PubMed Central

    Basu, Supratim; Ramegowda, Venkategowda; Kumar, Anuj; Pereira, Andy

    2016-01-01

    Plants in their natural habitats adapt to drought stress in the environment through a variety of mechanisms, ranging from transient responses to low soil moisture to major survival mechanisms of escape by early flowering in absence of seasonal rainfall. However, crop plants selected by humans to yield products such as grain, vegetable, or fruit in favorable environments with high inputs of water and fertilizer are expected to yield an economic product in response to inputs. Crop plants selected for their economic yield need to survive drought stress through mechanisms that maintain crop yield. Studies on model plants for their survival under stress do not, therefore, always translate to yield of crop plants under stress, and different aspects of drought stress response need to be emphasized. The crop plant model rice ( Oryza sativa) is used here as an example to highlight mechanisms and genes for adaptation of crop plants to drought stress. PMID:27441087

  17. Adaptive boxcar/wavelet transform

    NASA Astrophysics Data System (ADS)

    Sezer, Osman G.; Altunbasak, Yucel

    2009-01-01

    This paper presents a new adaptive Boxcar/Wavelet transform for image compression. Boxcar/Wavelet decomposition emphasizes the idea of average-interpolation representation which uses dyadic averages and their interpolation to explain a special case of biorthogonal wavelet transforms (BWT). This perspective for image compression together with lifting scheme offers the ability to train an optimum 2-D filter set for nonlinear prediction (interpolation) that will adapt to the context around the low-pass wavelet coefficients for reducing energy in the high-pass bands. Moreover, the filters obtained after training is observed to posses directional information with some textural clues that can provide better prediction performance. This work addresses a firrst step towards obtaining this new set of training-based fillters in the context of Boxcar/Wavelet transform. Initial experimental results show better subjective quality performance compared to popular 9/7-tap and 5/3-tap BWTs with comparable results in objective quality.

  18. Recursive adaptive frame integration limited

    NASA Astrophysics Data System (ADS)

    Rafailov, Michael K.

    2006-05-01

    Recursive Frame Integration Limited was proposed as a way to improve frame integration performance and mitigate issues related to high data rate needed for conventional frame integration. The technique applies two thresholds - one tuned for optimum probability of detection, the other to manage required false alarm rate - and allows a non-linear integration process that, along with Signal-to-Noise Ratio (SNR) gain, provides system designers more capability where cost, weight, or power considerations limit system data rate, processing, or memory capability. However, Recursive Frame Integration Limited may have performance issues when single frame SNR is really low. Recursive Adaptive Frame Integration Limited is proposed as a means to improve limited integration performance with really low single frame SNR. It combines the benefits of nonlinear recursive limited frame integration and adaptive thresholds with a kind of conventional frame integration.

  19. Coherent Digital Holographic Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Liu, Changgeng

    A new type of adaptive optics (AO) based on the principles of digital holography (DH) is proposed and developed for the use in wide-field and confocal retinal imaging. Digital holographic adaptive optics (DHAO) dispenses with the wavefront sensor and wavefront corrector of the conventional AO system. DH is an emergent imaging technology that gives direct numerical access to the phase of the optical field, thus allowing precise control and manipulation of the optical field. Incorporation of DH in an ophthalmic imaging system can lead to versatile imaging capabilities at substantially reduced complexity and cost of the instrument. A typical conventional AO system includes several critical hardware pieces: spatial light modulator, lenslet array, and a second CCD camera in addition to the camera for imaging. The proposed DHAO system replaces these hardware components with numerical processing for wavefront measurement and compensation of aberration through the principles of DH. (Abstract shortened by UMI.).

  20. Evolutionary adaptations to dietary changes.

    PubMed

    Luca, F; Perry, G H; Di Rienzo, A

    2010-08-21

    Through cultural innovation and changes in habitat and ecology, there have been a number of major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. The identification of signatures of adaptations to such dietary changes in the genome of extant primates (including humans) may shed light not only on the evolutionary history of our species, but also on the mechanisms that underlie common metabolic diseases in modern human populations. In this review, we provide a brief overview of the major dietary shifts that occurred during hominin evolution, and we discuss the methods and approaches used to identify signals of natural selection in patterns of sequence variation. We then review the results of studies aimed at detecting the genetic loci that played a major role in dietary adaptations and conclude by outlining the potential of future studies in this area.

  1. Anisotropic grid adaptation in LES

    NASA Astrophysics Data System (ADS)

    Toosi, Siavash; Larsson, Johan

    2016-11-01

    The modeling errors depend directly on the grid (or filter) spacing in turbulence-resolving simulations (LES, DNS, DES, etc), and are typically at least as significant as the numerical errors. This makes adaptive grid-refinement complicated, since it prevents the estimation of the local error sources through numerical analysis. The present work attempts to address this difficulty with a physics-based error-source indicator that accounts for the anisotropy in the smallest resolved scales, which can thus be used to drive an anisotropic grid-adaptation process. The proposed error indicator is assessed on a sequence of problems, including turbulent channel flow and flows in more complex geometries. The formulation is geometrically general and applicable to complex geometries.

  2. Making Intelligent Systems Adaptive. (Revision)

    DTIC Science & Technology

    1988-10-01

    eventually produce solutions. BY contrast, human beinge and other intelligent animls continuously adapt to the demands and opportunities presented by a...such as monitoring critically ill medical patients or controlling a manufacturing process. Following the model set by human intelligence, we define...signs probabilistically, using a belief network, as well as from first principles, using explicit models of system structure and function. Concurrent

  3. Extreme Adaptive Optics Planet Imager

    NASA Astrophysics Data System (ADS)

    Macintosh, B.; Graham, J. R.; Ghez, A.; Kalas, P.; Lloyd, J.; Makidon, R.; Olivier, S.; Patience, J.; Perrin, M.; Poyneer, L.; Severson, S.; Sheinis, A.; Sivaramakrishnan, A.; Troy, M.; Wallace, J.; Wilhelmsen, J.

    2002-12-01

    Direct detection of photons emitted or reflected by extrasolar planets is the next major step in extrasolar planet studies. Current adaptive optics (AO) systems, with <300 subapertures and Strehl ratio 0.4-0.7, can achieve contrast levels of 106 at 2" separations; this is sufficient to see very young planets in wide orbits but insufficient to detect solar systems more like our own. Contrast levels of 107 - 108 in the near-IR are needed to probe a significant part of the extrasolar planet phase space. The NSF Center for Adaptive Optics is carrying out a design study for a dedicated ultra-high-contrast "Extreme" adaptive optics system for an 8-10m telescope. With 3000 controlled subapertures it should achieve Strehl ratios > 0.9 in the near-IR. Using a spatially filtered wavefront sensor, the system will be optimized to control scattered light over a large radius and suppress artifacts caused static errors. We predict that it will achieve contrast levels of 107-108 around a large sample of stars (R<7-10), sufficient to detect Jupiter-like planets through their near-IR emission over a wide range of ages and masses. The system will be capable of a variety of high-contrast science including studying circumstellar dust disks at densities a factor of 10-100 lower than currently feasible and a systematic inventory of other solar systems on 10-100 AU scale. This work was supported by the NSF Science and Technology Center for Adaptive Optics, managed by UC Santa Cruz under AST-9876783. Portions of this work was performed under the auspices of the U.S. Department of Energy, under contract No. W-7405-Eng-48.

  4. Measuring high-altitude adaptation.

    PubMed

    Moore, Lorna G

    2017-08-31

    High altitudes (>8000 ft or 2500 m) provide an experiment of nature for measuring adaptation and the physiological processes involved. Studies conducted over the past ~25 years in Andeans, Tibetans, and less often Ethiopians show varied but distinct O2 transport traits from those of acclimatized newcomers, providing indirect evidence for genetic adaptation to high altitude. Short-term (acclimatization, developmental) and long-term (genetic) responses to high altitude exhibit a temporal gradient such that, while all influence O2 content, the latter also improve O2 delivery and metabolism. Much has been learned concerning the underlying physiological processes but additional studies are needed on the regulation of blood flow and O2 utilization. Direct evidence of genetic adaptation comes from single nucleotide polymorphism (SNP)-based genome scans and whole-genome sequencing studies that have identified gene regions acted upon by natural selection. Efforts have begun to understand the connections between the two with Andean studies on the genetic factors raising uterine blood flow, fetal growth, and susceptibility to Chronic Mountain Sickness and Tibetan studies on genes serving to lower hemoglobin and pulmonary arterial pressure. Critical for future studies will be the selection of phenotypes with demonstrable effects on reproductive success, the calculation of actual fitness costs, and greater inclusion of women among the subjects being studied. The well-characterized nature of the O2 transport system, the presence of multiple long-resident populations, and relevance for understanding hypoxic disorders in all persons underscore the importance of understanding how evolutionary adaptation to high altitude has occurred. Copyright © 2017, Journal of Applied Physiology.

  5. Complex Adaptive Special Operations (CASO)

    DTIC Science & Technology

    2007-01-01

    impeded by an organizational command and control superstructure designed to support a centralized decision making process. The four components of...and David. Organizational Survival in the New World: The Intelligent Complex Adaptive System (Burlington, MA: KMCI Press, 2004), 295. 2 Clay, Peter... Behavoir , http://en.wikipedia.org/wiki/flocking_%28behavior%29, accessed 2 December 2006. 54 Possible CASO rules may include: exposure – don’t get

  6. Family Adaptation in the Military

    DTIC Science & Technology

    1990-05-01

    the especially important role of unit level leaders to the development of supportive relationships among ...service members, a convergence toward less traditional gender - role preferences among men and women in marriage, and an emerging preference by an...upon them. In an analysis of a world-wide survey of Army families, it was found that the perceived adaptability of the family depended upon the

  7. Adaptive Search through Constraint Violations

    DTIC Science & Technology

    1990-01-01

    ZIP Code) 3939 O’Hara Street 800 North Quincy Street Pittsburgh, PA 15260 Arlington, VA 22217-5000 8a NAME OF FUNDING/SPONSORING Bb OFFICE SYMBOL 9...Pittsburgh, PA . Smith, D. A., Greeno, J. G., & Vitolo, T. M., (in press). A model of competence for counting. Cognitive Science. VanLehn, K. (in press...1990). Adaptive search through constraint violations (Technical Report No. KUL-90-01). Pittsburgh, PA : Learning Research and Development Center

  8. Adaptive Reactive Rich Internet Applications

    NASA Astrophysics Data System (ADS)

    Schmidt, Kay-Uwe; Stühmer, Roland; Dörflinger, Jörg; Rahmani, Tirdad; Thomas, Susan; Stojanovic, Ljiljana

    Rich Internet Applications significantly raise the user experience compared with legacy page-based Web applications because of their highly responsive user interfaces. Although this is a tremendous advance, it does not solve the problem of the one-size-fits-all approach1 of current Web applications. So although Rich Internet Applications put the user in a position to interact seamlessly with the Web application, they do not adapt to the context in which the user is currently working. In this paper we address the on-the-fly personalization of Rich Internet Applications. We introduce the concept of ARRIAs: Adaptive Reactive Rich Internet Applications and elaborate on how they are able to adapt to the current working context the user is engaged in. An architecture for the ad hoc adaptation of Rich Internet Applications is presented as well as a holistic framework and tools for the realization of our on-the-fly personalization approach. We divided both the architecture and the framework into two levels: offline/design-time and online/run-time. For design-time we explain how to use ontologies in order to annotate Rich Internet Applications and how to use these annotations for conceptual Web usage mining. Furthermore, we describe how to create client-side executable rules from the semantic data mining results. We present our declarative lightweight rule language tailored to the needs of being executed directly on the client. Because of the event-driven nature of the user interfaces of Rich Internet Applications, we designed a lightweight rule language based on the event-condition-action paradigm.2 At run-time the interactions of a user are tracked directly on the client and in real-time a user model is built up. The user model then acts as input to and is evaluated by our client-side complex event processing and rule engine.

  9. Adaptation and Foreign Policy Theory

    DTIC Science & Technology

    1973-09-01

    ADAPTATION AND FOREIGN POLICY THEORY © AKFSIIM t* «ns white i»i R Hi Stuart J. Thorson Project for Theoretical Politics Department of...Policy Stud^es. Prepared In connection with research supported by the Advanced Research Projects Agency, ARPA Order Ho.23l* S - 3D20, Contract No. DAHC15...will become more clear as this paper progresses. -2- Flrst, however. It Is Important to briefly outline what sort of " theory " of foreign policy

  10. An adaptive level set method

    SciTech Connect

    Milne, Roger Brent

    1995-12-01

    This thesis describes a new method for the numerical solution of partial differential equations of the parabolic type on an adaptively refined mesh in two or more spatial dimensions. The method is motivated and developed in the context of the level set formulation for the curvature dependent propagation of surfaces in three dimensions. In that setting, it realizes the multiple advantages of decreased computational effort, localized accuracy enhancement, and compatibility with problems containing a range of length scales.

  11. Micromirror Arrays for Adaptive Optics

    SciTech Connect

    Carr, E.J.

    2000-08-07

    The long-range goal of this project is to develop the optical and mechanical design of a micromirror array for adaptive optics that will meet the following criteria: flat mirror surface ({lambda}/20), high fill factor (> 95%), large stroke (5-10 {micro}m), and pixel size {approx}-200 {micro}m. This will be accomplished by optimizing the mirror surface and actuators independently and then combining them using bonding technologies that are currently being developed.

  12. META II Complexity and Adaptability

    DTIC Science & Technology

    2011-08-01

    looks for the highest peaks, Robust Design looks for the highest mesas – regions where the performance does not fall off due to small variations in...ATA 23 (Communications), ATA 24(Electrical Power), ATA 27(Flight Controls), ATA 29(Hydraulics), ATA 30(Ice and Rain Protection ),ATA 31(Indicating...though a degree of adaptation may be required. 4.5. Experimentation The experiments we have performed in the program fall into two broad categories

  13. Natural pedagogy as evolutionary adaptation.

    PubMed

    Csibra, Gergely; Gergely, György

    2011-04-12

    We propose that the cognitive mechanisms that enable the transmission of cultural knowledge by communication between individuals constitute a system of 'natural pedagogy' in humans, and represent an evolutionary adaptation along the hominin lineage. We discuss three kinds of arguments that support this hypothesis. First, natural pedagogy is likely to be human-specific: while social learning and communication are both widespread in non-human animals, we know of no example of social learning by communication in any other species apart from humans. Second, natural pedagogy is universal: despite the huge variability in child-rearing practices, all human cultures rely on communication to transmit to novices a variety of different types of cultural knowledge, including information about artefact kinds, conventional behaviours, arbitrary referential symbols, cognitively opaque skills and know-how embedded in means-end actions. Third, the data available on early hominin technological culture are more compatible with the assumption that natural pedagogy was an independently selected adaptive cognitive system than considering it as a by-product of some other human-specific adaptation, such as language. By providing a qualitatively new type of social learning mechanism, natural pedagogy is not only the product but also one of the sources of the rich cultural heritage of our species.

  14. Dynamic Adaption of Vascular Morphology

    PubMed Central

    Okkels, Fridolin; Jacobsen, Jens Christian Brings

    2012-01-01

    The structure of vascular networks adapts continuously to meet changes in demand of the surrounding tissue. Most of the known vascular adaptation mechanisms are based on local reactions to local stimuli such as pressure and flow, which in turn reflects influence from the surrounding tissue. Here we present a simple two-dimensional model in which, as an alternative approach, the tissue is modeled as a porous medium with intervening sharply defined flow channels. Based on simple, physiologically realistic assumptions, flow-channel structure adapts so as to reach a configuration in which all parts of the tissue are supplied. A set of model parameters uniquely determine the model dynamics, and we have identified the region of the best-performing model parameters (a global optimum). This region is surrounded in parameter space by less optimal model parameter values, and this separation is characterized by steep gradients in the related fitness landscape. Hence it appears that the optimal set of parameters tends to localize close to critical transition zones. Consequently, while the optimal solution is stable for modest parameter perturbations, larger perturbations may cause a profound and permanent shift in systems characteristics. We suggest that the system is driven toward a critical state as a consequence of the ongoing parameter optimization, mimicking an evolutionary pressure on the system. PMID:23060814

  15. Certification Considerations for Adaptive Systems

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Siddhartha; Cofer, Darren; Musliner, David J.; Mueller, Joseph; Engstrom, Eric

    2015-01-01

    Advanced capabilities planned for the next generation of aircraft, including those that will operate within the Next Generation Air Transportation System (NextGen), will necessarily include complex new algorithms and non-traditional software elements. These aircraft will likely incorporate adaptive control algorithms that will provide enhanced safety, autonomy, and robustness during adverse conditions. Unmanned aircraft will operate alongside manned aircraft in the National Airspace (NAS), with intelligent software performing the high-level decision-making functions normally performed by human pilots. Even human-piloted aircraft will necessarily include more autonomy. However, there are serious barriers to the deployment of new capabilities, especially for those based upon software including adaptive control (AC) and artificial intelligence (AI) algorithms. Current civil aviation certification processes are based on the idea that the correct behavior of a system must be completely specified and verified prior to operation. This report by Rockwell Collins and SIFT documents our comprehensive study of the state of the art in intelligent and adaptive algorithms for the civil aviation domain, categorizing the approaches used and identifying gaps and challenges associated with certification of each approach.

  16. Metabolic Adaptation to Muscle Ischemia

    NASA Technical Reports Server (NTRS)

    Cabrera, Marco E.; Coon, Jennifer E.; Kalhan, Satish C.; Radhakrishnan, Krishnan; Saidel, Gerald M.; Stanley, William C.

    2000-01-01

    Although all tissues in the body can adapt to varying physiological/pathological conditions, muscle is the most adaptable. To understand the significance of cellular events and their role in controlling metabolic adaptations in complex physiological systems, it is necessary to link cellular and system levels by means of mechanistic computational models. The main objective of this work is to improve understanding of the regulation of energy metabolism during skeletal/cardiac muscle ischemia by combining in vivo experiments and quantitative models of metabolism. Our main focus is to investigate factors affecting lactate metabolism (e.g., NADH/NAD) and the inter-regulation between carbohydrate and fatty acid metabolism during a reduction in regional blood flow. A mechanistic mathematical model of energy metabolism has been developed to link cellular metabolic processes and their control mechanisms to tissue (skeletal muscle) and organ (heart) physiological responses. We applied this model to simulate the relationship between tissue oxygenation, redox state, and lactate metabolism in skeletal muscle. The model was validated using human data from published occlusion studies. Currently, we are investigating the difference in the responses to sudden vs. gradual onset ischemia in swine by combining in vivo experimental studies with computational models of myocardial energy metabolism during normal and ischemic conditions.

  17. Driver Code for Adaptive Optics

    NASA Technical Reports Server (NTRS)

    Rao, Shanti

    2007-01-01

    A special-purpose computer code for a deformable-mirror adaptive-optics control system transmits pixel-registered control from (1) a personal computer running software that generates the control data to (2) a circuit board with 128 digital-to-analog converters (DACs) that generate voltages to drive the deformable-mirror actuators. This program reads control-voltage codes from a text file, then sends them, via the computer s parallel port, to a circuit board with four AD5535 (or equivalent) chips. Whereas a similar prior computer program was capable of transmitting data to only one chip at a time, this program can send data to four chips simultaneously. This program is in the form of C-language code that can be compiled and linked into an adaptive-optics software system. The program as supplied includes source code for integration into the adaptive-optics software, documentation, and a component that provides a demonstration of loading DAC codes from a text file. On a standard Windows desktop computer, the software can update 128 channels in 10 ms. On Real-Time Linux with a digital I/O card, the software can update 1024 channels (8 boards in parallel) every 8 ms.

  18. Anatomical adaptations of aquatic mammals.

    PubMed

    Reidenberg, Joy S

    2007-06-01

    This special issue of the Anatomical Record explores many of the anatomical adaptations exhibited by aquatic mammals that enable life in the water. Anatomical observations on a range of fossil and living marine and freshwater mammals are presented, including sirenians (manatees and dugongs), cetaceans (both baleen whales and toothed whales, including dolphins and porpoises), pinnipeds (seals, sea lions, and walruses), the sea otter, and the pygmy hippopotamus. A range of anatomical systems are covered in this issue, including the external form (integument, tail shape), nervous system (eye, ear, brain), musculoskeletal systems (cranium, mandible, hyoid, vertebral column, flipper/forelimb), digestive tract (teeth/tusks/baleen, tongue, stomach), and respiratory tract (larynx). Emphasis is placed on exploring anatomical function in the context of aquatic life. The following topics are addressed: evolution, sound production, sound reception, feeding, locomotion, buoyancy control, thermoregulation, cognition, and behavior. A variety of approaches and techniques are used to examine and characterize these adaptations, ranging from dissection, to histology, to electron microscopy, to two-dimensional (2D) and 3D computerized tomography, to experimental field tests of function. The articles in this issue are a blend of literature review and new, hypothesis-driven anatomical research, which highlight the special nature of anatomical form and function in aquatic mammals that enables their exquisite adaptation for life in such a challenging environment. 2007 Wiley-Liss, Inc.

  19. Adaptive Batch Mode Active Learning.

    PubMed

    Chakraborty, Shayok; Balasubramanian, Vineeth; Panchanathan, Sethuraman

    2015-08-01

    Active learning techniques have gained popularity to reduce human effort in labeling data instances for inducing a classifier. When faced with large amounts of unlabeled data, such algorithms automatically identify the exemplar and representative instances to be selected for manual annotation. More recently, there have been attempts toward a batch mode form of active learning, where a batch of data points is simultaneously selected from an unlabeled set. Real-world applications require adaptive approaches for batch selection in active learning, depending on the complexity of the data stream in question. However, the existing work in this field has primarily focused on static or heuristic batch size selection. In this paper, we propose two novel optimization-based frameworks for adaptive batch mode active learning (BMAL), where the batch size as well as the selection criteria are combined in a single formulation. We exploit gradient-descent-based optimization strategies as well as properties of submodular functions to derive the adaptive BMAL algorithms. The solution procedures have the same computational complexity as existing state-of-the-art static BMAL techniques. Our empirical results on the widely used VidTIMIT and the mobile biometric (MOBIO) data sets portray the efficacy of the proposed frameworks and also certify the potential of these approaches in being used for real-world biometric recognition applications.

  20. Retinotopy of facial expression adaptation.

    PubMed

    Matsumiya, Kazumichi

    2014-01-01

    The face aftereffect (FAE; the illusion of faces after adaptation to a face) has been reported to occur without retinal overlap between adaptor and test, but recent studies revealed that the FAE is not constant across all test locations, which suggests that the FAE is also retinotopic. However, it remains unclear whether the characteristic of the retinotopy of the FAE for one facial aspect is the same as that of the FAE for another facial aspect. In the research reported here, an examination of the retinotopy of the FAE for facial expression indicated that the facial expression aftereffect occurs without retinal overlap between adaptor and test, and depends on the retinal distance between them. Furthermore, the results indicate that, although dependence of the FAE on adaptation-test distance is similar between facial expression and facial identity, the FAE for facial identity is larger than that for facial expression when a test face is presented in the opposite hemifield. On the basis of these results, I discuss adaptation mechanisms underlying facial expression processing and facial identity processing for the retinotopy of the FAE.

  1. Metabolic Adaptation to Muscle Ischemia

    NASA Technical Reports Server (NTRS)

    Cabrera, Marco E.; Coon, Jennifer E.; Kalhan, Satish C.; Radhakrishnan, Krishnan; Saidel, Gerald M.; Stanley, William C.

    2000-01-01

    Although all tissues in the body can adapt to varying physiological/pathological conditions, muscle is the most adaptable. To understand the significance of cellular events and their role in controlling metabolic adaptations in complex physiological systems, it is necessary to link cellular and system levels by means of mechanistic computational models. The main objective of this work is to improve understanding of the regulation of energy metabolism during skeletal/cardiac muscle ischemia by combining in vivo experiments and quantitative models of metabolism. Our main focus is to investigate factors affecting lactate metabolism (e.g., NADH/NAD) and the inter-regulation between carbohydrate and fatty acid metabolism during a reduction in regional blood flow. A mechanistic mathematical model of energy metabolism has been developed to link cellular metabolic processes and their control mechanisms to tissue (skeletal muscle) and organ (heart) physiological responses. We applied this model to simulate the relationship between tissue oxygenation, redox state, and lactate metabolism in skeletal muscle. The model was validated using human data from published occlusion studies. Currently, we are investigating the difference in the responses to sudden vs. gradual onset ischemia in swine by combining in vivo experimental studies with computational models of myocardial energy metabolism during normal and ischemic conditions.

  2. Sparse-aperture adaptive optics

    NASA Astrophysics Data System (ADS)

    Tuthill, Peter; Lloyd, James; Ireland, Michael; Martinache, Frantz; Monnier, John; Woodruff, Henry; ten Brummelaar, Theo; Turner, Nils; Townes, Charles

    2006-06-01

    Aperture masking interferometry and Adaptive Optics (AO) are two of the competing technologies attempting to recover diffraction-limited performance from ground-based telescopes. However, there are good arguments that these techniques should be viewed as complementary, not competitive. Masking has been shown to deliver superior PSF calibration, rejection of atmospheric noise and robust recovery of phase information through the use of closure phases. However, this comes at the penalty of loss of flux at the mask, restricting the technique to bright targets. Adaptive optics, on the other hand, can reach a fainter class of objects but suffers from the difficulty of calibration of the PSF which can vary with observational parameters such as seeing, airmass and source brightness. Here we present results from a fusion of these two techniques: placing an aperture mask downstream of an AO system. The precision characterization of the PSF enabled by sparse-aperture interferometry can now be applied to deconvolution of AO images, recovering structure from the traditionally-difficult regime within the core of the AO-corrected transfer function. Results of this program from the Palomar and Keck adaptive optical systems are presented.

  3. Adaptation Driven by Spatial Heterogeneities

    NASA Astrophysics Data System (ADS)

    Hermsen, Rutger

    2011-03-01

    Biological evolution and ecology are intimately linked, because the reproductive success or ``fitness'' of an organism depends crucially on its ecosystem. Yet, most models of evolution (or population genetics) consider homogeneous, fixed-size populations subjected to a constant selection pressure. To move one step beyond such ``mean field'' descriptions, we discuss stochastic models of evolution driven by spatial heterogeneity. We imagine a population whose range is limited by a spatially varying environmental parameter, such as a temperature or the concentration of an antibiotic drug. Individuals in the population replicate, die and migrate stochastically. Also, by mutation, they can adapt to the environmental stress and expand their range. This way, adaptation and niche expansion go hand in hand. This mode of evolution is qualitatively different from the usual notion of a population climbing a fitness gradient. We analytically calculate the rate of adaptation by solving a first passage time problem. Interestingly, the joint effects of reproduction, death, mutation and migration result in two distinct parameter regimes depending on the relative time scales of mutation and migration. We argue that the proposed scenario may be relevant for the rapid evolution of antibiotic resistance. This work was supported by the Center for Theoretical Biological Physics sponsored by the National Science Foundation (NSF) (Grant PHY-0822283).

  4. Adaptive interface for spoken dialog

    NASA Astrophysics Data System (ADS)

    Dusan, Sorin; Flanagan, James

    2002-05-01

    Speech has become increasingly important in human-computer interaction. Spoken dialog interfaces rely on automatic speech recognition, speech synthesis, language understanding, and dialog management. A main issue in dialog systems is that they typically are limited to pre-programmed vocabularies and sets of sentences. The research reported here focuses on developing an adaptive spoken dialog interface capable of acquiring new linguistic units and their corresponding semantics during the human-computer interaction. The adaptive interface identifies unknown words and phrases in the users utterances and asks the user for the corresponding semantics. The user can provide the meaning or the semantic representation of the new linguistic units through multiple modalities, including speaking, typing, pointing, touching, or showing. The interface then stores the new linguistic units in a semantic grammar and creates new objects defining the corresponding semantic representation. This process takes place during natural interaction between user and computer and, thus, the interface does not have to be rewritten and compiled to incorporate the newly acquired language. Users can personalize the adaptive spoken interface for different domain applications, or according to their personal preferences. [Work supported by NSF.

  5. Natural pedagogy as evolutionary adaptation

    PubMed Central

    Csibra, Gergely; Gergely, György

    2011-01-01

    We propose that the cognitive mechanisms that enable the transmission of cultural knowledge by communication between individuals constitute a system of ‘natural pedagogy’ in humans, and represent an evolutionary adaptation along the hominin lineage. We discuss three kinds of arguments that support this hypothesis. First, natural pedagogy is likely to be human-specific: while social learning and communication are both widespread in non-human animals, we know of no example of social learning by communication in any other species apart from humans. Second, natural pedagogy is universal: despite the huge variability in child-rearing practices, all human cultures rely on communication to transmit to novices a variety of different types of cultural knowledge, including information about artefact kinds, conventional behaviours, arbitrary referential symbols, cognitively opaque skills and know-how embedded in means-end actions. Third, the data available on early hominin technological culture are more compatible with the assumption that natural pedagogy was an independently selected adaptive cognitive system than considering it as a by-product of some other human-specific adaptation, such as language. By providing a qualitatively new type of social learning mechanism, natural pedagogy is not only the product but also one of the sources of the rich cultural heritage of our species. PMID:21357237

  6. Adaptive management of urban watersheds

    NASA Astrophysics Data System (ADS)

    Garmestani, A.; Shuster, W.; Green, O. O.

    2013-12-01

    Consent decree settlements for violations of the Clean Water Act (1972) increasingly include provisions for redress of combined sewer overflow activity through hybrid approaches that incorporate the best of both gray (e.g., storage tunnels) and green infrastructure (e.g., rain gardens). Adaptive management is an environmental management strategy that uses an iterative process of decision-making to improve environmental management via system monitoring. A central tenet of adaptive management is that management involves a learning process that can help regulated communities achieve environmental quality objectives. We are using an adaptive management approach to guide a green infrastructure retrofit of a neighborhood in the Slavic Village Development Corporation area (Cleveland, Ohio). We are in the process of gathering hydrologic and ecosystem services data and will use this data as a basis for collaboration with area citizens on a plan to use green infrastructure to contain stormflows. Monitoring data provides researchers with feedback on the impact of green infrastructure implementation and suggest where improvements can be made.

  7. Adaptive management for ecosystem services.

    PubMed

    Birgé, Hannah E; Allen, Craig R; Garmestani, Ahjond S; Pope, Kevin L

    2016-12-01

    Management of natural resources for the production of ecosystem services, which are vital for human well-being, is necessary even when there is uncertainty regarding system response to management action. This uncertainty is the result of incomplete controllability, complex internal feedbacks, and non-linearity that often interferes with desired management outcomes, and insufficient understanding of nature and people. Adaptive management was developed to reduce such uncertainty. We present a framework for the application of adaptive management for ecosystem services that explicitly accounts for cross-scale tradeoffs in the production of ecosystem services. Our framework focuses on identifying key spatiotemporal scales (plot, patch, ecosystem, landscape, and region) that encompass dominant structures and processes in the system, and includes within- and cross-scale dynamics, ecosystem service tradeoffs, and management controllability within and across scales. Resilience theory recognizes that a limited set of ecological processes in a given system regulate ecosystem services, yet our understanding of these processes is poorly understood. If management actions erode or remove these processes, the system may shift into an alternative state unlikely to support the production of desired services. Adaptive management provides a process to assess the underlying within and cross-scale tradeoffs associated with production of ecosystem services while proceeding with management designed to meet the demands of a growing human population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The Limits to Adaptation: A Systems Approach

    EPA Science Inventory

    The ability to adapt to climate change is delineated by capacity thresholds, after which climate damages begin to overwhelm the adaptation response. Such thresholds depend upon physical properties (natural processes and engineering parameters), resource constraints (expressed th...

  9. Understanding the adaptive approach to thermal comfort

    SciTech Connect

    Humphreys, M.A.; Nicol, J.F.

    1998-10-01

    This paper explains the adaptive approach to thermal comfort, and an adaptive model for thermal comfort is presented. The model is an example of a complex adaptive system (Casti 1996) whose equilibria are determined by the restrictions acting upon it. People`s adaptive actions are generally effective in securing comfort, which occurs at a wide variety of indoor temperatures. These comfort temperatures depend upon the circumstances in which people live, such as the climate and the heating or cooling regime. The temperatures may be estimated from the mean outdoor temperature and the availability of a heating or cooling plant. The evaluation of the parameters of the adaptive model requires cross-sectional surveys to establish current norms and sequential surveys (with and without intervention) to evaluate the rapidity of people`s adaptive actions. Standards for thermal comfort will need revision in the light of the adaptive approach. Implications of the adaptive model for the HVAC industry are noted.

  10. Enhancing climate Adaptation Capacity for Drinking Water ...

    EPA Pesticide Factsheets

    Journal article This paper considers the adaptation capacity of conventional water treatment systems. A modeling framework is used to illustrate climate adaptation mechanisms that could enable conventional treatment systems to accommodate water quality impairments.

  11. Reconceptualizing Family Adaptation to Developmental Delay.

    PubMed

    Pedersen, Anita L; Crnic, Keith A; Baker, Bruce L; Blacher, Jan

    2015-07-01

    This study explores accurate conceptualization of the adaptation construct in families of children with developmental delay aged 3 to 8 years. Parents' self-reported measures of adaptation and observed dyadic relationship variables were examined. Confirmatory factor analysis and longitudinal growth modeling were used to evaluate the nature of adaptational processes. Results indicate that adaptational processes vary across adaptation index, child developmental level, and parent gender. Adaptation indices did not load onto a single construct at any time point. Several adaptational processes remained stable across time, although others showed linear or quadratic change. The findings of the current study indicate that it is time for a change in how adaptation is conceived for families of children with developmental delay.

  12. Adaptive diagnosis of the bilinear mechanical systems

    NASA Astrophysics Data System (ADS)

    Gelman, L.; Gorpinich, S.; Thompson, C.

    2009-07-01

    A generic adaptive approach is proposed for diagnosis of the bilinear mechanical systems. The approach adapts the free oscillation method for bilinearity diagnosis of mechanical systems. The expediency of the adaptation is proved for a recognition feature, the decrement of the free oscillations. The developed adaptation consists of variation of the adaptive likelihood ratio of the decrement with variation of the resonance frequency of the bilinear system. It is shown that in the cases of the frequency-independent and the frequency-dependent internal damping, the adaptation is expedient. To investigate effectiveness of the adaptation in these cases, a numerical simulation was carried out. The simulation results show that use of the adaptation increases the total probability of the correct diagnosis of system bilinearity.

  13. A holistic strategy for adaptive land management

    USDA-ARS?s Scientific Manuscript database

    Adaptive management is widely applied to natural resources management. Adaptive management can be generally defined as an iterative decision-making process that incorporates formulation of management objectives, actions designed to address these objectives, monitoring of results, and repeated adapta...

  14. Adaptive Flight Control for Aircraft Safety Enhancements

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan T.; Gregory, Irene M.; Joshi, Suresh M.

    2008-01-01

    This poster presents the current adaptive control research being conducted at NASA ARC and LaRC in support of the Integrated Resilient Aircraft Control (IRAC) project. The technique "Approximate Stability Margin Analysis of Hybrid Direct-Indirect Adaptive Control" has been developed at NASA ARC to address the needs for stability margin metrics for adaptive control that potentially enables future V&V of adaptive systems. The technique "Direct Adaptive Control With Unknown Actuator Failures" is developed at NASA LaRC to deal with unknown actuator failures. The technique "Adaptive Control with Adaptive Pilot Element" is being researched at NASA LaRC to investigate the effects of pilot interactions with adaptive flight control that can have implications of stability and performance.

  15. Flipping Adapters for Space Launch System

    NASA Image and Video Library

    The structural test article adapter is flipped at Marshall testing facility Building 4705. The turnover is an important step in finishing the machining work on the adapter, which will undergo tests...

  16. IIR algorithms for adaptive line enhancement

    SciTech Connect

    David, R.A.; Stearns, S.D.; Elliott, G.R.; Etter, D.M.

    1983-01-01

    We introduce a simple IIR structure for the adaptive line enhancer. Two algorithms based on gradient-search techniques are presented for adapting the structure. Results from experiments which utilized real data as well as computer simulations are provided.

  17. The Limits to Adaptation: A Systems Approach

    EPA Science Inventory

    The ability to adapt to climate change is delineated by capacity thresholds, after which climate damages begin to overwhelm the adaptation response. Such thresholds depend upon physical properties (natural processes and engineering parameters), resource constraints (expressed th...

  18. Enhancing climate Adaptation Capacity for Drinking Water ...

    EPA Pesticide Factsheets

    Journal article This paper considers the adaptation capacity of conventional water treatment systems. A modeling framework is used to illustrate climate adaptation mechanisms that could enable conventional treatment systems to accommodate water quality impairments.

  19. Orientation program and adaptation: comment on Dilekmen.

    PubMed

    Aral, Neriman

    2008-12-01

    The effect of an orientation program on 110 students' adaptation to university life had a significantly higher mean, which indicated better adaptation by the group in the program but not by the group with no orientation.

  20. Synthesis of Adaptation Options for Coastal Areas

    EPA Pesticide Factsheets

    Adaptation can help reduce the long-term costs associated with climate change. This document provides an introduction to climate change impacts and adaptation options for estuaries, beaches and coastal areas.

  1. Flexible beam control using an adaptive truss

    NASA Technical Reports Server (NTRS)

    Warrington, Thomas J.; Horner, C. Garnett

    1990-01-01

    To demonstrate the feasibility of adaptive trusses for vibration suppression, a 12-ft-long beam is attached to a single cell of an adaptive truss which has three active battens. With the base of the adaptive truss attached to the laboratory frame, the measured strain of the vibrating beam shows the adaptive truss to be very effective in suppressing vibration when subjected to initial conditions. Control is accomplished by a PC/XT computer that implements an LQR-designed control law.

  2. LARP - An adaptive LDV signal processor

    NASA Technical Reports Server (NTRS)

    Baker, Glenn D.; Murphy, R. Jay; Meyers, James F.

    1988-01-01

    Recent attempts at realization of a frequency domain signal processor exhibit practical drawbacks such as manual gain, filter and sampling adjustments, and simplistic adaptations of frequency domain techniques. This paper introduces an adaptive LDV signal processor, one which requires no operator intervention under any circumstances by adapting dynamically to burst characteristics, while surpassing all previous techniques in range and accuracy.

  3. Filter. Remix. Make.: Cultivating Adaptability through Multimodality

    ERIC Educational Resources Information Center

    Dusenberry, Lisa; Hutter, Liz; Robinson, Joy

    2015-01-01

    This article establishes traits of adaptable communicators in the 21st century, explains why adaptability should be a goal of technical communication educators, and shows how multimodal pedagogy supports adaptability. Three examples of scalable, multimodal assignments (infographics, research interviews, and software demonstrations) that evidence…

  4. Feedback in Videogame-Based Adaptive Training

    ERIC Educational Resources Information Center

    Rivera, Iris Daliz

    2010-01-01

    The field of training has been changing rapidly due to advances in technology such as videogame-based adaptive training. Videogame-based adaptive training has provided flexibility and adaptability for training in cost-effective ways. Although this method of training may have many benefits for the trainee, current research has not kept up to pace…

  5. Feedback in Videogame-Based Adaptive Training

    ERIC Educational Resources Information Center

    Rivera, Iris Daliz

    2010-01-01

    The field of training has been changing rapidly due to advances in technology such as videogame-based adaptive training. Videogame-based adaptive training has provided flexibility and adaptability for training in cost-effective ways. Although this method of training may have many benefits for the trainee, current research has not kept up to pace…

  6. Adaptive Control Techniques for Large Space Structures

    DTIC Science & Technology

    1987-12-23

    mission objectives. In particular, uncertainties in both system dynamics and disturbance spectra characterizations (both time varying and stochastic... uncertainty ) significantly limit the performance attainable with fixed gain, fixed architecture controls. Therefore, the use of an adaptive system , where...Theoretical Development: The initial emphasis has been on slow adaptation, since this covers may LSS situations. Later on we will examine fast adaptation. The

  7. Developing Organizational Adaptability for Complex Environment

    ERIC Educational Resources Information Center

    Boylan, Steven A.; Turner, Kenneth A.

    2017-01-01

    Developing organizations capable of adapting requires leaders to set conditions. Setting conditions normally requires purposeful activities by the leadership to foster and develop leader and individual adaptability, supported by processes and activities that enable adaptive behaviors through the totality of the organization (Goldstein, Hazy, &…

  8. Scalable Adaptive Multilevel Solvers for Multiphysics Problems

    SciTech Connect

    Xu, Jinchao

    2014-11-26

    In this project, we carried out many studies on adaptive and parallel multilevel methods for numerical modeling for various applications, including Magnetohydrodynamics (MHD) and complex fluids. We have made significant efforts and advances in adaptive multilevel methods of the multiphysics problems: multigrid methods, adaptive finite element methods, and applications.

  9. Providing Adaptivity in Moodle LMS Courses

    ERIC Educational Resources Information Center

    Despotovic-Zrakic, Marijana; Markovic, Aleksandar; Bogdanovic, Zorica; Barac, Dusan; Krco, Srdjan

    2012-01-01

    In this paper, we describe an approach to providing adaptivity in e-education courses. The primary goal of the paper is to enhance an existing e-education system, namely Moodle LMS, by developing a method for creating adaptive courses, and to compare its effectiveness with non-adaptive education approach. First, we defined the basic requirements…

  10. Predictor-Based Model Reference Adaptive Control

    NASA Technical Reports Server (NTRS)

    Lavretsky, Eugene; Gadient, Ross; Gregory, Irene M.

    2010-01-01

    This paper is devoted to the design and analysis of a predictor-based model reference adaptive control. Stable adaptive laws are derived using Lyapunov framework. The proposed architecture is compared with the now classical model reference adaptive control. A simulation example is presented in which numerical evidence indicates that the proposed controller yields improved transient characteristics.

  11. Filter. Remix. Make.: Cultivating Adaptability through Multimodality

    ERIC Educational Resources Information Center

    Dusenberry, Lisa; Hutter, Liz; Robinson, Joy

    2015-01-01

    This article establishes traits of adaptable communicators in the 21st century, explains why adaptability should be a goal of technical communication educators, and shows how multimodal pedagogy supports adaptability. Three examples of scalable, multimodal assignments (infographics, research interviews, and software demonstrations) that evidence…

  12. National-level progress on adaptation

    NASA Astrophysics Data System (ADS)

    Lesnikowski, Alexandra; Ford, James; Biesbroek, Robbert; Berrang-Ford, Lea; Heymann, S. Jody

    2016-03-01

    It is increasingly evident that adaptation will figure prominently in the post-2015 United Nations climate change agreement. As adaptation obligations under the United Nations Framework Convention on Climate Change evolve, more rigorous approaches to measuring adaptation progress among parties will be critical. In this Letter we elaborate on an emerging area of research referred to as `adaptation tracking’, which has potential to inform development of a global adaptation monitoring framework. We evaluate this potential by presenting evidence on policy change for 41 high-income countries between 2010 and 2014. We examine whether countries that were in early stages of adaptation planning in 2010 are making progress to close adaptation gaps, and how the landscape of adaptation in these countries has evolved. In total we find an 87% increase in reported adaptation policies and measures, and evidence that implementation of concrete adaptation initiatives is growing. Reflecting on the strengths and challenges of this early methodology, we further discuss how adaptation tracking practices could guide development of a robust framework for monitoring global adaptation progress and inform future research on policy change across countries.

  13. Adaptive independent component analysis to analyze electrocardiograms

    NASA Astrophysics Data System (ADS)

    Yim, Seong-Bin; Szu, Harold H.

    2001-03-01

    In this work, we apply adaptive version independent component analysis (ADAPTIVE ICA) to the nonlinear measurement of electro-cardio-graphic (ECG) signals for potential detection of abnormal conditions in the heart. In principle, unsupervised ADAPTIVE ICA neural networks can demix the components of measured ECG signals. However, the nonlinear pre-amplification and post measurement processing make the linear ADAPTIVE ICA model no longer valid. This is possible because of a proposed adaptive rectification pre-processing is used to linearize the preamplifier of ECG, and then linear ADAPTIVE ICA is used in iterative manner until the outputs having their own stable Kurtosis. We call such a new approach adaptive ADAPTIVE ICA. Each component may correspond to individual heart function, either normal or abnormal. Adaptive ADAPTIVE ICA neural networks have the potential to make abnormal components more apparent, even when they are masked by normal components in the original measured signals. This is particularly important for diagnosis well in advance of the actual onset of heart attack, in which abnormalities in the original measured ECG signals may be difficult to detect. This is the first known work that applies Adaptive ADAPTIVE ICA to ECG signals beyond noise extraction, to the detection of abnormal heart function.

  14. An Authoring Environment for Adaptive Testing

    ERIC Educational Resources Information Center

    Guzman, Eduardo; Conejo, Ricardo; Garcia-Hervas; Emilio

    2005-01-01

    SIETTE is a web-based adaptive testing system. It implements Computerized Adaptive Tests. These tests are tailor-made, theory-based tests, where questions shown to students, finalization of the test, and student knowledge estimation is accomplished adaptively. To construct these tests, SIETTE has an authoring environment comprising a suite of…

  15. Adaptive Force Control in Compliant Motion

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1994-01-01

    This paper addresses the problem of controlling a manipulator in compliant motion while in contact with an environment having an unknown stiffness. Two classes of solutions are discussed: adaptive admittance control and adaptive compliance control. In both admittance and compliance control schemes, compensator adaptation is used to ensure a stable and uniform system performance.

  16. Using Bayesian belief networks in adaptive management.

    Treesearch

    J.B. Nyberg; B.G. Marcot; R. Sulyma

    2006-01-01

    Bayesian belief and decision networks are relatively new modeling methods that are especially well suited to adaptive-management applications, but they appear not to have been widely used in adaptive management to date. Bayesian belief networks (BBNs) can serve many purposes for practioners of adaptive management, from illustrating system relations conceptually to...

  17. Resilience thinking: integrating resilience, adaptability and transformability

    Treesearch

    Carl Folke; Stephen R. Carpenter; Brian Walker; Marten Scheffer; Terry Chapin; Johan. Rockstrom

    2010-01-01

    Resilience thinking addresses the dynamics and development of complex social-ecological systems (SES). Three aspects are central: resilience, adaptability and transformability. These aspects interrelate across multiple scales. Resilience in this context is the capacity of a SES to continually change and adapt yet remain within critical thresholds. Adaptability is part...

  18. Direct Adaptive Control Of An Industrial Robot

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun; Lee, Thomas; Delpech, Michel

    1992-01-01

    Decentralized direct adaptive control scheme for six-jointed industrial robot eliminates part of overall computational burden imposed by centralized controller and degrades performance of robot by reducing sampling rate. Control and controller-adaptation laws based on observed performance of manipulator: no need to model dynamics of robot. Adaptive controllers cope with uncertainties and variations in robot and payload.

  19. Inferential Aspects of Adaptive Allocation Rules.

    ERIC Educational Resources Information Center

    Berry, Donald A.

    In clinical trials, adaptive allocation means that the therapies assigned to the next patient or patients depend on the results obtained thus far in the trial. Although many adaptive allocation procedures have been proposed for clinical trials, few have actually used adaptive assignment, largely because classical frequentist measures of inference…

  20. The Worker as Proteus: Understanding Occupational Adaptability.

    ERIC Educational Resources Information Center

    Faddis, Constance R.

    The purpose of this paper is to review and synthesize what is known about occupational adaptability and to propose a heuristic model of the process(es) of adaptation in work. Following an introductory chapter, three chapters contain a review of literature that draws from many disciplines and presents an overview of human adaptation in general, as…

  1. Providing Adaptivity in Moodle LMS Courses

    ERIC Educational Resources Information Center

    Despotovic-Zrakic, Marijana; Markovic, Aleksandar; Bogdanovic, Zorica; Barac, Dusan; Krco, Srdjan

    2012-01-01

    In this paper, we describe an approach to providing adaptivity in e-education courses. The primary goal of the paper is to enhance an existing e-education system, namely Moodle LMS, by developing a method for creating adaptive courses, and to compare its effectiveness with non-adaptive education approach. First, we defined the basic requirements…

  2. Adaptation strategies and approaches: Chapter 2

    Treesearch

    Patricia Butler; Chris Swanston; Maria Janowiak; Linda Parker; Matt St. Pierre; Leslie. Brandt

    2012-01-01

    A wealth of information is available on climate change adaptation, but much of it is very broad and of limited use at the finer spatial scales most relevant to land managers. This chapter contains a "menu" of adaptation actions and provides land managers in northern Wisconsin with a range of options to help forest ecosystems adapt to climate change impacts....

  3. Frequency domain FIR and IIR adaptive filters

    NASA Technical Reports Server (NTRS)

    Lynn, D. W.

    1990-01-01

    A discussion of the LMS adaptive filter relating to its convergence characteristics and the problems associated with disparate eigenvalues is presented. This is used to introduce the concept of proportional convergence. An approach is used to analyze the convergence characteristics of block frequency-domain adaptive filters. This leads to a development showing how the frequency-domain FIR adaptive filter is easily modified to provide proportional convergence. These ideas are extended to a block frequency-domain IIR adaptive filter and the idea of proportional convergence is applied. Experimental results illustrating proportional convergence in both FIR and IIR frequency-domain block adaptive filters is presented.

  4. Adaptive vehicle motion estimation and prediction

    NASA Astrophysics Data System (ADS)

    Zhao, Liang; Thorpe, Chuck E.

    1999-01-01

    Accurate motion estimation and reliable maneuver prediction enable an automated car to react quickly and correctly to the rapid maneuvers of the other vehicles, and so allow safe and efficient navigation. In this paper, we present a car tracking system which provides motion estimation, maneuver prediction and detection of the tracked car. The three strategies employed - adaptive motion modeling, adaptive data sampling, and adaptive model switching probabilities - result in an adaptive interacting multiple model algorithm (AIMM). The experimental results on simulated and real data demonstrate that our tracking system is reliable, flexible, and robust. The adaptive tracking makes the system intelligent and useful in various autonomous driving tasks.

  5. Adaptive management of watersheds and related resources

    USGS Publications Warehouse

    Williams, Byron K.

    2009-01-01

    The concept of learning about natural resources through the practice of management has been around for several decades and by now is associated with the term adaptive management. The objectives of this paper are to offer a framework for adaptive management that includes an operational definition, a description of conditions in which it can be usefully applied, and a systematic approach to its application. Adaptive decisionmaking is described as iterative, learning-based management in two phases, each with its own mechanisms for feedback and adaptation. The linkages between traditional experimental science and adaptive management are discussed.

  6. [The local adaptation of clinical practice guidelines].

    PubMed

    Cavada, Luisa

    2014-01-01

    The ADAPTE process is a systematic approach to adapting guidelines produced in one setting for use in a different cultural and organizational context. It ensures that the guideline addresses specific health questions relevant to the context, accounting for the needs, priorities, legislation, policies, and resources in the targeted setting. The ADAPTE process was developed to meet the needs of different user groups, including guideline developers, health care providers, and policy makers at the local, national, and international level. The process is flexible; the transparent and explicit reporting enhances the quality and validity of the adapted guideline. The ADAPTE process is briefly described.

  7. The ERIS adaptive optics system

    NASA Astrophysics Data System (ADS)

    Marchetti, Enrico; Fedrigo, Enrico; Le Louarn, Miska; Madec, Pierre-Yves; Soenke, Christian; Brast, Roland; Conzelmann, Ralf; Delabre, Bernard; Duchateau, Michel; Frank, Christoph; Klein, Barbara; Amico, Paola; Hubin, Norbert; Esposito, Simone; Antichi, Jacopo; Carbonaro, Luca; Puglisi, Alfio; Quirós-Pacheco, Fernando; Riccardi, Armando; Xompero, Marco

    2014-07-01

    The Enhanced Resolution Imager and Spectrograph (ERIS) is the new Adaptive Optics based instrument for ESO's VLT aiming at replacing NACO and SINFONI to form a single compact facility with AO fed imaging and integral field unit spectroscopic scientific channels. ERIS completes the instrument suite at the VLT adaptive telescope. In particular it is equipped with a versatile AO system that delivers up to 95% Strehl correction in K band for science observations up to 5 micron It comprises high order NGS and LGS correction enabling the observation from exoplanets to distant galaxies with a large sky coverage thanks to the coupling of the LGS WFS with the high sensitivity of its visible WFS and the capability to observe in dust embedded environment thanks to its IR low order WFS. ERIS will be installed at the Cassegrain focus of the VLT unit hosting the Adaptive Optics Facility (AOF). The wavefront correction is provided by the AOF deformable secondary mirror while the Laser Guide Star is provided by one of the four launch units of the 4 Laser Guide Star Facility for the AOF. The overall layout of the ERIS AO system is extremely compact and highly optimized: the SPIFFI spectrograph is fed directly by the Cassegrain focus and both the NIX's (IR imager) and SPIFFI's entrance windows work as visible/infrared dichroics. In this paper we describe the concept of the ERIS AO system in detail, starting from the requirements and going through the estimated performance, the opto-mechanical design and the Real-Time Computer design.

  8. Adaptive capture of expert behavior

    SciTech Connect

    Jones, R.D.; Barrett, C.L.; Hand, U.; Gordon, R.C.

    1994-08-01

    The authors smoothed and captured a set of expert rules with adaptive networks. The motivation for doing this is discussed. (1) Smoothing leads to stabler control actions. (2) For some sets of rules, the evaluation of the rules can be sped up. This is important in large-scale simulations where many intelligent elements are present. (3) Variability of the intelligent elements can be achieved by adjusting the weights in an adaptive network. (4) After capture has occurred, the weights can be adjusted based on performance criteria. The authors thus have the capability of learning a new set of rules that lead to better performance. The set of rules the authors chose to capture were based on a set of threat determining rules for tank commanders. The approach in this paper: (1) They smoothed the rules. The rule set was converted into a simple set of arithmetic statements. Continuous, non-binary inputs, are now permitted. (2) An operational measure of capturability was developed. (3) They chose four candidate networks for the rule set capture: (a) multi-linear network, (b) adaptive partial least squares, (c) connectionist normalized local spline (CNLS) network, and (d) CNLS net with a PLS preprocessor. These networks were able to capture the rule set to within a few percent. For the simple tank rule set, the multi-linear network performed the best. When the rules were modified to include more nonlinear behavior, CNLS net performed better than the other three nets which made linear assumptions. (4) The networks were tested for robustness to input noise. Noise levels of plus or minus 10% had no real effect on the network performance. Noise levels in the plus or minus 30% range degraded performance by a factor of two. Some performance enhancement occurred when the networks were trained with noisy data. (5) The scaling of the evaluation time was calculated. (6) Human variation can be mimicked in all the networks by perturbing the weights.

  9. ERIS adaptive optics system design

    NASA Astrophysics Data System (ADS)

    Marchetti, Enrico; Le Louarn, Miska; Soenke, Christian; Fedrigo, Enrico; Madec, Pierre-Yves; Hubin, Norbert

    2012-07-01

    The Enhanced Resolution Imager and Spectrograph (ERIS) is the next-generation instrument planned for the Very Large Telescope (VLT) and the Adaptive Optics facility (AOF). It is an AO assisted instrument that will make use of the Deformable Secondary Mirror and the new Laser Guide Star Facility (4LGSF), and it is planned for the Cassegrain focus of the telescope UT4. The project is currently in its Phase A awaiting for approval to continue to the next phases. The Adaptive Optics system of ERIS will include two wavefront sensors (WFS) to maximize the coverage of the proposed sciences cases. The first is a high order 40x40 Pyramid WFS (PWFS) for on axis Natural Guide Star (NGS) observations. The second is a high order 40x40 Shack-Hartmann WFS for single Laser Guide Stars (LGS) observations. The PWFS, with appropriate sub-aperture binning, will serve also as low order NGS WFS in support to the LGS mode with a field of view patrolling capability of 2 arcmin diameter. Both WFSs will be equipped with the very low read-out noise CCD220 based camera developed for the AOF. The real-time reconstruction and control is provided by a SPARTA real-time platform adapted to support both WFS modes. In this paper we will present the ERIS AO system in all its main aspects: opto-mechanical design, real-time computer design, control and calibrations strategy. Particular emphasis will be given to the system performance obtained via dedicated numerical simulations.

  10. Plant adaptation to cold climates

    PubMed Central

    Körner, Christian

    2016-01-01

    In this short review, I will first summarize criteria by which environments can be considered “cold”, with plant stature (size, height above ground) playing a central role for the climate actually experienced. Plants adapted to such environments have to cope with both extremes and with gradual influences of low temperature. The first requires freezing resistance, which is tightly coupled to developmental state (phenology) and prehistory (acclimation). Gradual low temperature constraints affect the growth process (meristems) long before they affect photosynthetic carbon gain. Hence, plants growing in cold climates are commonly not carbon limited. PMID:27990251

  11. Test Target for Adaptive Optics.

    DTIC Science & Technology

    adaptive optics comprising, in the preferred embodiment, a plurality of nine adjacent, stacked, and aligned rows of a multiplicity of alternate opaque sections and transparent sections in a repeating bar pattern, with all sections being positioned on a flat transparent medium (such as film or glass), and with each opaque section being an opaque bar and with each transparent section being a transparent bar. Each row has a different spatial frequency than any other of the nine rows, with the spatial frequency of any one row being of a different multiple of the row having the

  12. Adaptive correction of ensemble forecasts

    NASA Astrophysics Data System (ADS)

    Pelosi, Anna; Battista Chirico, Giovanni; Van den Bergh, Joris; Vannitsem, Stephane

    2017-04-01

    Forecasts from numerical weather prediction (NWP) models often suffer from both systematic and non-systematic errors. These are present in both deterministic and ensemble forecasts, and originate from various sources such as model error and subgrid variability. Statistical post-processing techniques can partly remove such errors, which is particularly important when NWP outputs concerning surface weather variables are employed for site specific applications. Many different post-processing techniques have been developed. For deterministic forecasts, adaptive methods such as the Kalman filter are often used, which sequentially post-process the forecasts by continuously updating the correction parameters as new ground observations become available. These methods are especially valuable when long training data sets do not exist. For ensemble forecasts, well-known techniques are ensemble model output statistics (EMOS), and so-called "member-by-member" approaches (MBM). Here, we introduce a new adaptive post-processing technique for ensemble predictions. The proposed method is a sequential Kalman filtering technique that fully exploits the information content of the ensemble. One correction equation is retrieved and applied to all members, however the parameters of the regression equations are retrieved by exploiting the second order statistics of the forecast ensemble. We compare our new method with two other techniques: a simple method that makes use of a running bias correction of the ensemble mean, and an MBM post-processing approach that rescales the ensemble mean and spread, based on minimization of the Continuous Ranked Probability Score (CRPS). We perform a verification study for the region of Campania in southern Italy. We use two years (2014-2015) of daily meteorological observations of 2-meter temperature and 10-meter wind speed from 18 ground-based automatic weather stations distributed across the region, comparing them with the corresponding COSMO

  13. Method of adaptive artificial viscosity

    NASA Astrophysics Data System (ADS)

    Popov, I. V.; Fryazinov, I. V.

    2011-09-01

    A new finite-difference method for the numerical solution of gas dynamics equations is proposed. This method is a uniform monotonous finite-difference scheme of second-order approximation on time and space outside of domains of shock and compression waves. This method is based on inputting adaptive artificial viscosity (AAV) into gas dynamics equations. In this paper, this method is analyzed for 2D geometry. The testing computations of the movement of contact discontinuities and shock waves and the breakup of discontinuities are demonstrated.

  14. Adaptive-feedback control algorithm.

    PubMed

    Huang, Debin

    2006-06-01

    This paper is motivated by giving the detailed proofs and some interesting remarks on the results the author obtained in a series of papers [Phys. Rev. Lett. 93, 214101 (2004); Phys. Rev. E 71, 037203 (2005); 69, 067201 (2004)], where an adaptive-feedback algorithm was proposed to effectively stabilize and synchronize chaotic systems. This note proves in detail the strictness of this algorithm from the viewpoint of mathematics, and gives some interesting remarks for its potential applications to chaos control & synchronization. In addition, a significant comment on synchronization-based parameter estimation is given, which shows some techniques proposed in literature less strict and ineffective in some cases.

  15. [Wavefront analysis and adaptive optics].

    PubMed

    Stevens, J D; Sekundo, W

    2003-08-01

    In this paper we attempt to provide an overview of the principles of wavefront measurement. We also discuss the operational principles of different systems currently present on the market including their advantages and disadvantages. Moreover, we speculate on current and possible future implications of this new technology in the laser refractive surgery. Adaptive optics are explained in the context of "customized ablation" and preoperative verification of the desired results. Finally, the first international clinical results of wavefront guided excimer laser surgery are reviewed and critically commented.

  16. Emotional adaptation to limb loss.

    PubMed

    Belon, Howard P; Vigoda, Diane F

    2014-02-01

    Individuals experience multiple changes as a result of amputation. These changes not only are physical in nature but also may include psychological, financial, and comfort changes across the spectrum of an individual's life. It is important to assess the emotional responses that an individual may experience postsurgery and throughout the rehabilitation process. Grieving is a natural and normal emotional response postamputation. Grief resolution is one of the primary areas of focus in counseling amputees. This article examines various factors and strategies used in the adaptation and recovery from amputation.

  17. Strategies of Adaptive Ability Measurement.

    DTIC Science & Technology

    A number of strategies are described for adapting ability test items to individual differences in ability levels of testees. Each strategy consists of a different set of rules for selecting the sequence of test items to be administered to a given testee. Advantages and disadvantages of each strategy are discussed, and research issues unique to the strategy are described. Strategies reviewed are differentiated into two-stage approaches and multi-stage approaches. Several variations of the two-stage approach are described. The various

  18. An adaptive vector quantization scheme

    NASA Technical Reports Server (NTRS)

    Cheung, K.-M.

    1990-01-01

    Vector quantization is known to be an effective compression scheme to achieve a low bit rate so as to minimize communication channel bandwidth and also to reduce digital memory storage while maintaining the necessary fidelity of the data. However, the large number of computations required in vector quantizers has been a handicap in using vector quantization for low-rate source coding. An adaptive vector quantization algorithm is introduced that is inherently suitable for simple hardware implementation because it has a simple architecture. It allows fast encoding and decoding because it requires only addition and subtraction operations.

  19. Image space adaptive volume rendering

    NASA Astrophysics Data System (ADS)

    Corcoran, Andrew; Dingliana, John

    2012-01-01

    We present a technique for interactive direct volume rendering which provides adaptive sampling at a reduced memory requirement compared to traditional methods. Our technique exploits frame to frame coherence to quickly generate a two-dimensional importance map of the volume which guides sampling rate optimisation and allows us to provide interactive frame rates for user navigation and transfer function changes. In addition our ray casting shader detects any inconsistencies in our two-dimensional map and corrects them on the fly to ensure correct classification of important areas of the volume.

  20. Digital adaptive flight controller development

    NASA Technical Reports Server (NTRS)

    Kaufman, H.; Alag, G.; Berry, P.; Kotob, S.

    1974-01-01

    A design study of adaptive control logic suitable for implementation in modern airborne digital flight computers was conducted. Two designs are described for an example aircraft. Each of these designs uses a weighted least squares procedure to identify parameters defining the dynamics of the aircraft. The two designs differ in the way in which control law parameters are determined. One uses the solution of an optimal linear regulator problem to determine these parameters while the other uses a procedure called single stage optimization. Extensive simulation results and analysis leading to the designs are presented.