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Sample records for search space reduction

  1. Correspondence: Searching sequence space

    SciTech Connect

    Youvan, D.C.

    1995-08-01

    This correspondence debates the efficiency and application of genetic algorithms (GAs) to search protein sequence space. The important experimental point is that such sparse searches utilize physically realistic syntheses. In this regard, all GA-based technologies are very similar; they {open_quotes}learn{close_quotes} from their initial sparse search and then generate interesting new proteins within a few iterations. Which GA-based technology is best? That probably depends on the protein and the specific engineering goal. Given the fact that the field of combinatorial chemistry is still in its infancy, it is probably wise to consider all of the proven mutagenesis methods. 19 refs.

  2. Quantum Search in Hilbert Space

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2003-01-01

    A proposed quantum-computing algorithm would perform a search for an item of information in a database stored in a Hilbert-space memory structure. The algorithm is intended to make it possible to search relatively quickly through a large database under conditions in which available computing resources would otherwise be considered inadequate to perform such a task. The algorithm would apply, more specifically, to a relational database in which information would be stored in a set of N complex orthonormal vectors, each of N dimensions (where N can be exponentially large). Each vector would constitute one row of a unitary matrix, from which one would derive the Hamiltonian operator (and hence the evolutionary operator) of a quantum system. In other words, all the stored information would be mapped onto a unitary operator acting on a quantum state that would represent the item of information to be retrieved. Then one could exploit quantum parallelism: one could pose all search queries simultaneously by performing a quantum measurement on the system. In so doing, one would effectively solve the search problem in one computational step. One could exploit the direct- and inner-product decomposability of the unitary matrix to make the dimensionality of the memory space exponentially large by use of only linear resources. However, inasmuch as the necessary preprocessing (the mapping of the stored information into a Hilbert space) could be exponentially expensive, the proposed algorithm would likely be most beneficial in applications in which the resources available for preprocessing were much greater than those available for searching.

  3. Reduction in database search space by utilization of amino acid composition information from electron transfer dissociation and higher-energy collisional dissociation mass spectra.

    PubMed

    Hansen, Thomas A; Kryuchkov, Fedor; Kjeldsen, Frank

    2012-08-07

    With high-mass accuracy and consecutively obtained electron transfer dissociation (ETD) and higher-energy collisional dissociation (HCD) tandem mass spectrometry (MS/MS), reliable (≥97%) and sensitive fragment ions have been extracted for identification of specific amino acid residues in peptide sequences. The analytical benefit of these specific amino acid composition (AAC) ions is to restrict the database search space and provide identification of peptides with higher confidence and reduced false negative rates. The 6706 uniquely identified peptide sequences determined with a conservative Mascot score of >30 were used to characterize the AAC ions. The loss of amino acid side chains (small neutral losses, SNLs) from the charge reduced peptide radical cations was studied using ETD. Complementary AAC information from HCD spectra was provided by immonium ions. From the ETD/HCD mass spectra, 5162 and 6720 reliable SNLs and immonium ions were successfully extracted, respectively. Automated application of the AAC information during database searching resulted in an average 3.5-fold higher confidence level of peptide identification. In addition, 4% and 28% more peptides were identified above the significance level in a standard and extended search space, respectively.

  4. The connector space reduction mechanism

    NASA Technical Reports Server (NTRS)

    Milam, M. Bruce

    1990-01-01

    The Connector Space Reduction Mechanism (CSRM) is a simple device that can reduce the number of electromechanical devices on the Payload Interface Adapter/Station Interface Adapter (PIA/SIA) from 4 to 1. The device uses simplicity to attack the heart of the connector mating problem for large interfaces. The CSRM allows blind mate connector mating with minimal alignment required over short distances. This eliminates potential interface binding problems and connector damage. The CSRM is compatible with G and H connectors and Moog Rotary Shutoff fluid couplings. The CSRM can be used also with less forgiving connectors, as was demonstrated in the lab. The CSRM is NASA-Goddard exclusive design with patent applied for. The CSRM is the correct mechanism for the PIA/SIA interface as well as other similar berthing interfaces.

  5. The Nature of Reduction in Space Weathering

    NASA Astrophysics Data System (ADS)

    McKay, D. S.; Allen, C. C.

    1993-07-01

    Space weathering is a broad term that includes a number of complex effects of the exposure of materials to the environment of space. The processes that drive space weathering include micrometeorite impact, radiation from the Sun and cosmic rays, and exposure to the vacuum of space. One of the important effects caused by these processes is the tendency for chemical reduction of oxide and silicate materials (including glasses), with accompanying loss of oxygen and production of reduced metal. Such chemical reduction and accompanying metal production may have an important influence on the chemistry of the outermost volume of individual grains as well as on the optical properties of this material. Hapke [1] discussed five processes that have been suggested for producing submicroscopic iron metal in the lunar soil: (1) shock reduction, (2) heating in a thermal blanket in vacuum, (3) shock heating of solar-wind-impregnated grains, (4) coatings deposited by solar wind sputtering, and (5) coatings deposited by impact vaporization. As noted by Hapke, "Processes (1) and (2) have been refuted by laboratory experiments. Processes (4) and (5) have produced submicroscopic iron metal in laboratory simulations. Although no experiments have been done to simulate process (3), it is widely accepted." We have been performing experimental reduction of simulated and actual lunar materials [2-5] and have shown that, under conditions of exposure to hydrogen at elevated temperatures, reduction of FeO readily occurs in ilmenite and lunar composition glass, and occurs at a slower rate in pyroxene and olivine. Even plagioclase feldspar containing minor FeO is readily reduced with formation of metallic iron blebs on surfaces [4]. A comparison of natural lunar samples to hydrogen-reduced samples or simulants in which we are searching for reduction evidence in various soil phases is underway. Preliminary data for mature soils show, in agreement with earlier results, that reduced iron produced in

  6. Similarity searching in large combinatorial chemistry spaces

    NASA Astrophysics Data System (ADS)

    Rarey, Matthias; Stahl, Martin

    2001-06-01

    We present a novel algorithm, called Ftrees-FS, for similarity searching in large chemistry spaces based on dynamic programming. Given a query compound, the algorithm generates sets of compounds from a given chemistry space that are similar to the query. The similarity search is based on the feature tree similarity measure representing molecules by tree structures. This descriptor allows handling combinatorial chemistry spaces as a whole instead of looking at subsets of enumerated compounds. Within few minutes of computing time, the algorithm is able to find the most similar compound in very large spaces as well as sets of compounds at an arbitrary similarity level. In addition, the diversity among the generated compounds can be controlled. A set of 17 000 fragments of known drugs, generated by the RECAP procedure from the World Drug Index, was used as the search chemistry space. These fragments can be combined to more than 1018 compounds of reasonable size. For validation, known antagonists/inhibitors of several targets including dopamine D4, histamine H1, and COX2 are used as queries. Comparison of the compounds created by Ftrees-FS to other known actives demonstrates the ability of the method to jump between structurally unrelated molecule classes.

  7. A search for closely spaced gravitational lenses

    SciTech Connect

    Crampton, D.; Mcclure, R.D.; Fletcher, J.M.; Hutchings, J.B. National Research Council of Canada, Herzberg Institute of Astrophysics, Ottawa )

    1989-10-01

    A new image-stabilizing camera was used to search for closely spaced images of a sample of 25 intrinsically luminous quasars with z greater than 1.6 and m smaller than 19. Observations of seven similarly selected quasars with the regular CCD camera in good seeing conditions are also reported. Of the 32 quasars, seven are gravitational lens candidates. Two of these have subarcsecond separations. Additional information on all these candidates is required. 22 refs.

  8. Spaced-based search coil magnetometers

    NASA Astrophysics Data System (ADS)

    Hospodarsky, George B.

    2016-12-01

    Search coil magnetometers are one of the primary tools used to study the magnetic component of low-frequency electromagnetic waves in space. Their relatively small size, mass, and power consumption, coupled with a good frequency range and sensitivity, make them ideal for spaceflight applications. The basic design of a search coil magnetometer consists of many thousands of turns of wire wound on a high permeability core. When a time-varying magnetic field passes through the coil, a time-varying voltage is induced due to Faraday's law of magnetic induction. The output of the coil is usually attached to a preamplifier, which amplifies the induced voltage and conditions the signal for transmission to the main electronics (usually a low-frequency radio receiver). Search coil magnetometers are usually used in conjunction with electric field antenna to measure electromagnetic plasma waves in the frequency range of a few hertz to a few tens of kilohertzs. Search coil magnetometers are used to determine the properties of waves, such as comparing the relative electric and magnetic field amplitudes of the waves, or to investigate wave propagation parameters, such as Poynting flux and wave normal vectors. On a spinning spacecraft, they are also sometimes used to determine the background magnetic field. This paper presents some of the basic design criteria of search coil magnetometers and discusses design characteristics of sensors flown on a number of spacecraft.

  9. Searching Across the International Space Station Databases

    NASA Technical Reports Server (NTRS)

    Maluf, David A.; McDermott, William J.; Smith, Ernest E.; Bell, David G.; Gurram, Mohana

    2007-01-01

    Data access in the enterprise generally requires us to combine data from different sources and different formats. It is advantageous thus to focus on the intersection of the knowledge across sources and domains; keeping irrelevant knowledge around only serves to make the integration more unwieldy and more complicated than necessary. A context search over multiple domain is proposed in this paper to use context sensitive queries to support disciplined manipulation of domain knowledge resources. The objective of a context search is to provide the capability for interrogating many domain knowledge resources, which are largely semantically disjoint. The search supports formally the tasks of selecting, combining, extending, specializing, and modifying components from a diverse set of domains. This paper demonstrates a new paradigm in composition of information for enterprise applications. In particular, it discusses an approach to achieving data integration across multiple sources, in a manner that does not require heavy investment in database and middleware maintenance. This lean approach to integration leads to cost-effectiveness and scalability of data integration with an underlying schemaless object-relational database management system. This highly scalable, information on demand system framework, called NX-Search, which is an implementation of an information system built on NETMARK. NETMARK is a flexible, high-throughput open database integration framework for managing, storing, and searching unstructured or semi-structured arbitrary XML and HTML used widely at the National Aeronautics Space Administration (NASA) and industry.

  10. Exhaustive search system and method using space-filling curves

    DOEpatents

    Spires, Shannon V.

    2003-10-21

    A search system and method for one agent or for multiple agents using a space-filling curve provides a way to control one or more agents to cover an area of any space of any dimensionality using an exhaustive search pattern. An example of the space-filling curve is a Hilbert curve. The search area can be a physical geography, a cyberspace search area, or an area searchable by computing resources. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace.

  11. NASA's Orbital Space Plane Risk Reduction Strategy

    NASA Technical Reports Server (NTRS)

    Dumbacher, Dan

    2003-01-01

    This paper documents the transformation of NASA s Space Launch Initiative (SLI) Second Generation Reusable Launch Vehicle Program under the revised Integrated Space Transportation Plan, announced November 2002. Outlining the technology development approach followed by the original SLI, this paper gives insight into the current risk-reduction strategy that will enable confident development of the Nation s first orbital space plane (OSP). The OSP will perform an astronaut and contingency cargo transportation function, with an early crew rescue capability, thus enabling increased crew size and enhanced science operations aboard the International Space Station. The OSP design chosen for full-scale development will take advantage of the latest innovations American industry has to offer. The OSP Program identifies critical technologies that must be advanced to field a safe, reliable, affordable space transportation system for U.S. access to the Station and low-Earth orbit. OSP flight demonstrators will test crew safety features, validate autonomous operations, and mature thermal protection systems. Additional enabling technologies may be identified during the OSP design process as part of an overall risk-management strategy. The OSP Program uses a comprehensive and evolutionary systems acquisition approach, while applying appropriate lessons learned.

  12. Search for complex organic molecules in space

    NASA Astrophysics Data System (ADS)

    Ohishi, Masatoshi

    2016-07-01

    It was 1969 when the first organic molecule in space, H2CO, was discovered. Since then many organic molecules were discovered by using the NRAO 11 m (upgraded later to 12 m), Nobeyama 45 m, IRAM 30 m, and other highly sensitive radio telescopes as a result of close collaboration between radio astronomers and microwave spectroscopists. It is noteworthy that many famous organic molecules such as CH3OH, C2H5OH, (CH3)2O and CH3NH2 were detected by 1975. Organic molecules were found in so-called hot cores where molecules were thought to form on cold dust surfaces and then to evaporate by the UV photons emitted from the central star. These days organic molecules are known to exist not only in hot cores but in hot corinos (a warm, compact molecular clump found in the inner envelope of a class 0 protostar) and even protoplanetary disks. As was described above, major organic molecules were known since 1970s. It was very natural that astronomers considered a relationship between organic molecules in space and the origin of life. Several astronomers challenged to detect glycine and other prebiotic molecules without success. ALMA is expected to detect such important materials to further consider the gexogenous deliveryh hypothesis. In this paper I summarize the history in searching for complex organic molecules together with difficulties in observing very weak signals from larger species. The awfully long list of references at the end of this article may be the most useful part for readers who want to feel the exciting discovery stories.

  13. Background reduction using single-photoelectron counting for WIMP search

    NASA Astrophysics Data System (ADS)

    Ogawa, I.; Hazama, R.; Mukaida, K.; Kishimoto, K.; Kobayashi, T.; Tomii, S.; Sakai, H.; Katsuki, A.; Itamura, T.; Tanaka, Y.; Umehara, S.; Yoshida, S.; Matsuoka, K.; Kishimoto, T.

    2013-03-01

    We have developed a new background reduction method based on single photoelectron counting of scintillators for the WIMP search experiment. We introduced this method to our detector system ELEGANT VI, which has an active shield in all directions (4π) using a pulse height or, equivalently, the difference in the number of photoelectrons between two (left and right) photomultiplier tubes attached to CaF2 scintillators. The number distribution is uniquely described by a binomial function, via which we developed the unambiguous background subtraction method. This method reduces the backgrounds further compared to charge-sensitive ADC and offers improved sensitivity for the search for WIMPs.

  14. Model reduction for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Williams, Trevor

    1992-01-01

    Model reduction is an important practical problem in the control of flexible spacecraft, and a considerable amount of work has been carried out on this topic. Two of the best known methods developed are modal truncation and internal balancing. Modal truncation is simple to implement but can give poor results when the structure possesses clustered natural frequencies, as often occurs in practice. Balancing avoids this problem but has the disadvantages of high computational cost, possible numerical sensitivity problems, and no physical interpretation for the resulting balanced 'modes'. The purpose of this work is to examine the performance of the subsystem balancing technique developed by the investigator when tested on a realistic flexible space structure, in this case a model of the Permanently Manned Configuration (PMC) of Space Station Freedom. This method retains the desirable properties of standard balancing while overcoming the three difficulties listed above. It achieves this by first decomposing the structural model into subsystems of highly correlated modes. Each subsystem is approximately uncorrelated from all others, so balancing them separately and then combining yields comparable results to balancing the entire structure directly. The operation count reduction obtained by the new technique is considerable: a factor of roughly r(exp 2) if the system decomposes into r equal subsystems. Numerical accuracy is also improved significantly, as the matrices being operated on are of reduced dimension, and the modes of the reduced-order model now have a clear physical interpretation; they are, to first order, linear combinations of repeated-frequency modes.

  15. Markovian Search Games in Heterogeneous Spaces

    SciTech Connect

    Griffin, Christopher H

    2009-01-01

    We consider how to search for a mobile evader in a large heterogeneous region when sensors are used for detection. Sensors are modeled using probability of detection. Due to environmental effects, this probability will not be constant over the entire region. We map this problem to a graph search problem and, even though deterministic graph search is NP-complete, we derive a tractable, optimal, probabilistic search strategy. We do this by defining the problem as a differential game played on a Markov chain. We prove that this strategy is optimal in the sense of Nash. Simulations of an example problem illustrate our approach and verify our claims.

  16. Search Space Characterization for a Telescope Scheduling Application

    NASA Technical Reports Server (NTRS)

    Bresina, John; Drummond, Mark; Swanson, Keith; Friedland, Peter (Technical Monitor)

    1994-01-01

    This paper presents a technique for statistically characterizing a search space and demonstrates the use of this technique within a practical telescope scheduling application. The characterization provides the following: (i) an estimate of the search space size, (ii) a scaling technique for multi-attribute objective functions and search heuristics, (iii) a "quality density function" for schedules in a search space, (iv) a measure of a scheduler's performance, and (v) support for constructing and tuning search heuristics. This paper describes the random sampling algorithm used to construct this characterization and explains how it can be used to produce this information. As an example, we include a comparative analysis of an heuristic dispatch scheduler and a look-ahead scheduler that performs greedy search.

  17. International Space Station (ISS) Risk Reduction Activities

    NASA Technical Reports Server (NTRS)

    Fodroci, Michael

    2011-01-01

    As the assembly of the ISS nears completion, it is worthwhile to step back and review some of the actions pursued by the Program in recent years to reduce risk and enhance the safety and health of ISS crewmembers, visitors, and space flight participants. While the ISS requirements and initial design were intended to provide the best practicable levels of safety, it is always possible to reduce risk -- given the determination and commitment to do so. The following is a summary of some of the steps taken by the ISS Program Manager, by our International Partners, by hardware and software designers, by operational specialists, and by safety personnel to continuously enhance the safety of the ISS. While decades of work went into developing the ISS requirements, there are many things in a Program like the ISS that can only be learned through actual operational experience. These risk reduction activities can be divided into roughly three categories: (1) Areas that were initially noncompliant which have subsequently been brought into compliance or near compliance (i.e., Micrometeoroid and Orbital Debris [MMOD] protection, acoustics) (2) Areas where initial design requirements were eventually considered inadequate and were subsequently augmented (i.e., Toxicity Level 4 materials, emergency hardware and procedures) (3) Areas where risks were initially underestimated, and have subsequently been addressed through additional mitigation (i.e., Extravehicular Activity [EVA] sharp edges, plasma shock hazards) Due to the hard work and cooperation of many parties working together across the span of nearly a decade, the ISS is now a safer and healthier environment for our crew, in many cases exceeding the risk reduction targets inherent in the intent of the original design. It will provide a safe and stable platform for utilization and discovery.

  18. A Theoretical Analysis of the k-Satisfiability Search Space

    NASA Astrophysics Data System (ADS)

    Sutton, Andrew M.; Howe, Adele E.; Whitley, L. Darrell

    Local search algorithms perform surprisingly well on the k-satisfiability (k-SAT) problem. However, few theoretical analyses of the k-SAT search space exist. In this paper we study the search space of the k-SAT problem and show that it can be analyzed by a decomposition. In particular, we prove that the objective function can be represented as a superposition of exactly k elementary landscapes. We show that this decomposition allows us to immediately compute the expectation of the objective function evaluated across neighboring points. We use this result to prove previously unknown bounds for local maxima and plateau width in the 3-SAT search space. We compute these bounds numerically for a number of instances and show that they are non-trivial across a large set of benchmarks.

  19. A search for space energy alternatives

    NASA Technical Reports Server (NTRS)

    Gilbreath, W. P.; Billman, K. W.

    1978-01-01

    This paper takes a look at a number of schemes for converting radiant energy in space to useful energy for man. These schemes are possible alternatives to the currently most studied solar power satellite concept. Possible primary collection and conversion devices discussed include the space particle flux devices, solar windmills, photovoltaic devices, photochemical cells, photoemissive converters, heat engines, dielectric energy conversion, electrostatic generators, plasma solar collectors, and thermionic schemes. Transmission devices reviewed include lasers and masers.

  20. Dimensionality reduction by supervised neighbor embedding using laplacian search.

    PubMed

    Zheng, Jianwei; Zhang, Hangke; Cattani, Carlo; Wang, Wanliang

    2014-01-01

    Dimensionality reduction is an important issue for numerous applications including biomedical images analysis and living system analysis. Neighbor embedding, those representing the global and local structure as well as dealing with multiple manifolds, such as the elastic embedding techniques, can go beyond traditional dimensionality reduction methods and find better optima. Nevertheless, existing neighbor embedding algorithms can not be directly applied in classification as suffering from several problems: (1) high computational complexity, (2) nonparametric mappings, and (3) lack of class labels information. We propose a supervised neighbor embedding called discriminative elastic embedding (DEE) which integrates linear projection matrix and class labels into the final objective function. In addition, we present the Laplacian search direction for fast convergence. DEE is evaluated in three aspects: embedding visualization, training efficiency, and classification performance. Experimental results on several benchmark databases present that the proposed DEE exhibits a supervised dimensionality reduction approach which not only has strong pattern revealing capability, but also brings computational advantages over standard gradient based methods.

  1. Minimizing the search space in sniper localization using sensor configuration

    NASA Astrophysics Data System (ADS)

    Damarla, Thyagaraju

    2010-04-01

    In this paper an algorithm for sniper localization using disparate single microphone sensors that uses only the time difference of arrival (TDOA) between muzzle blast and shock wave is presented. Just as in any algorithm that looks for optimal solution this algorithm also faces the local minima (possible sniper locations) problem. In order to find the global or near global solution one has to perform search over a large area. In order to reduce the computational burden, the search space needs to be small. In this paper, an upper and lower bound on the range for the search space are estimated using the sensor configuration. Based on this, the area around the bullets path is searched with the bounds on range to determine the exact or near global solution for the sniper location. The results of sniper localization algorithm applied to real data collected in a field test will be presented.

  2. Noise environment reduction foam spheres in space

    NASA Technical Reports Server (NTRS)

    Scharton, Terry; Kern, Dennis; Badilla, Gloria

    1989-01-01

    The advent of lightweight fairings for new spacecraft and the increased thrust of new launch vehicles have intensified the need for better techniques for predicting and for reducing the low frequency noise environment of spacecraft at liftoff. This paper presents a VAPEPS (VibroAcoustic Payload Environment Prediction System) parametrical analysis of the noise reduction of spacecraft fairings and explores a novel technique for increasing the low frequency noise reduction of lightweight fairing by approximately 10 dB.

  3. State space forecasting and noise reduction

    SciTech Connect

    Eubank, S.; Casdagli, M.; Farmer, J.D.; Gibson, J.

    1990-01-01

    We discuss the effects of nonlinearity and noise on the problem of finding states and dynamics. We point out problems which arise in the construction of state space models for scalar time series. We describe solutions for the case when error due to noise dominates parameter estimation error and outline a framework for the general case.

  4. Phase space reduction and Poisson structure

    NASA Astrophysics Data System (ADS)

    Zaalani, Nadhem

    1999-07-01

    Let (P,π,B,G) be a G-principal fiber bundle. The action of G on the cotangent bundle T*P is free and Hamiltonian. By Liberman and Marle [Symplectic Geometry and Analytical Mechanics (Reidel, Dortrecht, 1987)] and Marsden and Ratiu [Lett. Math. Phys. 11, 161 (1981)] the quotient space T*P/G is a Poisson manifold. We will determine the Poisson bracket on the reduced Poisson manifold T*P/G, and its symplectic leaves.

  5. Archaeological Remote Sensing: Searching for Fort Clatsop from Space

    NASA Technical Reports Server (NTRS)

    Karsmizki, Kenneth W.; Spruce, Joe; Giardino, Marco

    2002-01-01

    The Columbia Gorge Discovery Center and NASA's Stennis Space Center have teamed up to use high-resolution aerial and satellite-based remote sensing in the search for Lewis and Clark expedition campsites. A Space Act Agreement between NASA and the Discovery Center has evolved into a study that employs remote sensing, plus modern and historical map data for relocating several Lewis and Clark encampments. Satellite data being studied include 30-meter Landsat Thematic Mapper and 1-meter Space Imaging IKONOS data. This paper includes an overview of the working relationship between NASA and the Discovery Center. It also reports on geospatial analyses of the Fort Clatsop site to demonstrate the ways geospatial technologies interface with the written and cartographic records of the expedition and how they are applied to the search for Lewis and Clark campsites.

  6. Exploration of Stellarator Configuration Space with Global Search Methods

    SciTech Connect

    H.E. Mynick; N. Pomphrey; S. Ethier

    2001-09-10

    An exploration of stellarator configuration space z for quasi-axisymmetric stellarator (QAS) designs is discussed, using methods which provide a more global view of that space. To this end, we have implemented a ''differential evolution'' (DE) search algorithm in an existing stellarator optimizer, which is much less prone to become trapped in local, suboptimal minima of the cost function chi than the local search methods used previously. This search algorithm is complemented by mapping studies of chi over z aimed at gaining insight into the results of the automated searches. We find that a wide range of the attractive QAS configurations previously found fall into a small number of classes, with each class corresponding to a basin of chi(z). We develop maps on which these earlier stellarators can be placed, the relations among them seen, and understanding gained into the physics differences between them. It is also found that, while still large, the region of z space containing practically realizable QAS configurations is much smaller than earlier supposed.

  7. Euclidean sections of protein conformation space and their implications in dimensionality reduction.

    PubMed

    Duan, Mojie; Li, Minghai; Han, Li; Huo, Shuanghong

    2014-10-01

    Dimensionality reduction is widely used in searching for the intrinsic reaction coordinates for protein conformational changes. We find the dimensionality-reduction methods using the pairwise root-mean-square deviation (RMSD) as the local distance metric face a challenge. We use Isomap as an example to illustrate the problem. We believe that there is an implied assumption for the dimensionality-reduction approaches that aim to preserve the geometric relations between the objects: both the original space and the reduced space have the same kind of geometry, such as Euclidean geometry vs. Euclidean geometry or spherical geometry vs. spherical geometry. When the protein free energy landscape is mapped onto a 2D plane or 3D space, the reduced space is Euclidean, thus the original space should also be Euclidean. For a protein with N atoms, its conformation space is a subset of the 3N-dimensional Euclidean space R(3N). We formally define the protein conformation space as the quotient space of R(3N) by the equivalence relation of rigid motions. Whether the quotient space is Euclidean or not depends on how it is parameterized. When the pairwise RMSD is employed as the local distance metric, implicit representations are used for the protein conformation space, leading to no direct correspondence to a Euclidean set. We have demonstrated that an explicit Euclidean-based representation of protein conformation space and the local distance metric associated to it improve the quality of dimensionality reduction in the tetra-peptide and β-hairpin systems.

  8. An ant colony algorithm on continuous searching space

    NASA Astrophysics Data System (ADS)

    Xie, Jing; Cai, Chao

    2015-12-01

    Ant colony algorithm is heuristic, bionic and parallel. Because of it is property of positive feedback, parallelism and simplicity to cooperate with other method, it is widely adopted in planning on discrete space. But it is still not good at planning on continuous space. After a basic introduction to the basic ant colony algorithm, we will propose an ant colony algorithm on continuous space. Our method makes use of the following three tricks. We search for the next nodes of the route according to fixed-step to guarantee the continuity of solution. When storing pheromone, it discretizes field of pheromone, clusters states and sums up the values of pheromone of these states. When updating pheromone, it makes good resolutions measured in relative score functions leave more pheromone, so that ant colony algorithm can find a sub-optimal solution in shorter time. The simulated experiment shows that our ant colony algorithm can find sub-optimal solution in relatively shorter time.

  9. Localization Versus Abstraction: A Comparison of Two Search Reduction Techniques

    NASA Technical Reports Server (NTRS)

    Lansky, Amy L.

    1992-01-01

    There has been much recent work on the use of abstraction to improve planning behavior and cost. Another technique for dealing with the inherently explosive cost of planning is localization. This paper compares the relative strengths of localization and abstraction in reducing planning search cost. In particular, localization is shown to subsume abstraction. Localization techniques can model the various methods of abstraction that have been used, but also provide a much more flexible framework, with a broader range of benefits.

  10. Systematic Dimensionality Reduction for Quantum Walks: Optimal Spatial Search and Transport on Non-Regular Graphs

    NASA Astrophysics Data System (ADS)

    Novo, Leonardo; Chakraborty, Shantanav; Mohseni, Masoud; Neven, Hartmut; Omar, Yasser

    2015-09-01

    Continuous time quantum walks provide an important framework for designing new algorithms and modelling quantum transport and state transfer problems. Often, the graph representing the structure of a problem contains certain symmetries that confine the dynamics to a smaller subspace of the full Hilbert space. In this work, we use invariant subspace methods, that can be computed systematically using the Lanczos algorithm, to obtain the reduced set of states that encompass the dynamics of the problem at hand without the specific knowledge of underlying symmetries. First, we apply this method to obtain new instances of graphs where the spatial quantum search algorithm is optimal: complete graphs with broken links and complete bipartite graphs, in particular, the star graph. These examples show that regularity and high-connectivity are not needed to achieve optimal spatial search. We also show that this method considerably simplifies the calculation of quantum transport efficiencies. Furthermore, we observe improved efficiencies by removing a few links from highly symmetric graphs. Finally, we show that this reduction method also allows us to obtain an upper bound for the fidelity of a single qubit transfer on an XY spin network.

  11. Systematic Dimensionality Reduction for Quantum Walks: Optimal Spatial Search and Transport on Non-Regular Graphs

    PubMed Central

    Novo, Leonardo; Chakraborty, Shantanav; Mohseni, Masoud; Neven, Hartmut; Omar, Yasser

    2015-01-01

    Continuous time quantum walks provide an important framework for designing new algorithms and modelling quantum transport and state transfer problems. Often, the graph representing the structure of a problem contains certain symmetries that confine the dynamics to a smaller subspace of the full Hilbert space. In this work, we use invariant subspace methods, that can be computed systematically using the Lanczos algorithm, to obtain the reduced set of states that encompass the dynamics of the problem at hand without the specific knowledge of underlying symmetries. First, we apply this method to obtain new instances of graphs where the spatial quantum search algorithm is optimal: complete graphs with broken links and complete bipartite graphs, in particular, the star graph. These examples show that regularity and high-connectivity are not needed to achieve optimal spatial search. We also show that this method considerably simplifies the calculation of quantum transport efficiencies. Furthermore, we observe improved efficiencies by removing a few links from highly symmetric graphs. Finally, we show that this reduction method also allows us to obtain an upper bound for the fidelity of a single qubit transfer on an XY spin network. PMID:26330082

  12. The Space Physics of Life: Searching for Biosignatures on Habitable Icy Worlds Affected by Space Weathering

    NASA Technical Reports Server (NTRS)

    Cooper, John F.

    2006-01-01

    Accessible surfaces of the most likely astrobiological habitats (Mars, Europa, Titan) in the solar system beyond Earth are exposed to various chemical and hydrologic weathering processes directly or indirectly induced by interaction with the overlying space environment. These processes can be both beneficial, through provision of chemical compounds and energy, and destructive, through chemical dissociation or burial, to detectable presence of biosignatures. Orbital, suborbital, and surface platforms carrying astrobiological instrumentation must survive, and preferably exploit, space environment interactions to reach these habitats and search for evidence of life or its precursors. Experience from Mars suggests that any detection of biosignatures must be accompanied by characterization of the local chemical environment and energy sources including irradiation by solar ultraviolet photons and energetic particles from the space environment. Orbital and suborbital surveys of surface chemistry and astrobiological potential in the context of the space environment should precede targeted in-situ measurements to maximize probability of biosignature detection through site selection. The Space Physics of Life (SPOL) investigation has recently been proposed to the NASA Astrobiology Institute and is briefly described in this presentation. SPOL is the astrobiologically relevant study of the interactions and relationships of potentially? or previously inhabited, bodies of the solar system with the surrounding environments. This requires an interdisciplinary effort in space physics, planetary science, and radiation biology. The proposed investigation addresses the search for habitable environments, chemical resources to support life, and techniques for detection of organic and inorganic signs of life in the context of the space environment.

  13. Propeller noise reduction by means of unsymmetrical blade-spacing

    NASA Astrophysics Data System (ADS)

    Dobrzynski, W.

    1993-05-01

    The noise reduction potential of propellers with circumferentially unsymmetrical blade-spacing is predicted on theoretical grounds and substantiated through both aerodynamic and aeroacoustic full scale wind tunnel experiments. To avoid potential balancing problems such propellers have two (or several) pairs of opposite blades, each such pair constituting a symmetrical two-blade propeller. Spacing angles between these individual blade pairs are optimized towards achieving minimum A-weighted noise radiation in the plane of rotation. The result is then compared with the corresponding noise level from a symmetrical reference propeller with the same total number of geometrically identical blades. The study reveals that the value of the optimum spacing angle depends almost entirely on the operational helical blade-tip Mach number, assuming values of about 40 deg at a Mach number of O.5 and decreasing to 15 deg at a Mach number of 0.8. The noise reduction to be achieved from such unsymmetrical blade-spacing is limited to about 4 dB(A) in the direction of maximum noise radiation since the related acoustic effect is due to interference between the sound pressure signatures of the individual blades. It is found that both the harmonic sound pressure level spectrum and the acoustic directivity pattern is affected.

  14. Searching for Planets with the Space Interferometry Mission

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen

    2000-01-01

    The Space Interferometry Mission (SIM) will be the first space-based long baseline Michelson interferometer designed for precision astrometry. It will address a wide range of problems in stellar astrophysics and Galactic structure, delivering precision astrometry of stars down to 20 magnitude throughout the entire Galaxy. SIM uses a 10-m Michelson interferometer in Earth-trailing solar orbit to provide 4 microarcsecond (gas) precision astrometry. With a 5-year mission lifetime, SIM will be a powerful tool for discovering planets around nearby stars, through detection of the stellar reflex motion. The astrometric method complements the radial velocity technique which as already yielded many new planets, with an important benefit of directly measuring planetary masses. SIM will have a single-measurement precision of 1 microarcsecond in a frame defined by nearby reference stars, enabling searches for planets with masses as small as a few earth masses around the nearest stars. More massive planets will be detectable to much larger distances. In addition to precision astrometry SIM will also serve an important role as a technology precursor for future astrophysics missions using interferometers. Two technologies demonstrated will be high dynamic-range aperture synthesis imaging at 10-milliarcsec resolution in the optical, and fringe nulling to 10 (exp -4).

  15. Hiding and Searching Strategies of Adult Humans in a Virtual and a Real-Space Room

    ERIC Educational Resources Information Center

    Talbot, Katherine J.; Legge, Eric L. G.; Bulitko, Vadim; Spetch, Marcia L.

    2009-01-01

    Adults searched for or cached three objects in nine hiding locations in a virtual room or a real-space room. In both rooms, the locations selected by participants differed systematically between searching and hiding. Specifically, participants moved farther from origin and dispersed their choices more when hiding objects than when searching for…

  16. Navigating the Neural Space in Search of the Neural Code.

    PubMed

    Jazayeri, Mehrdad; Afraz, Arash

    2017-03-08

    The advent of powerful perturbation tools, such as optogenetics, has created new frontiers for probing causal dependencies in neural and behavioral states. These approaches have significantly enhanced the ability to characterize the contribution of different cells and circuits to neural function in health and disease. They have shifted the emphasis of research toward causal interrogations and increased the demand for more precise and powerful tools to control and manipulate neural activity. Here, we clarify the conditions under which measurements and perturbations support causal inferences. We note that the brain functions at multiple scales and that causal dependencies may be best inferred with perturbation tools that interface with the system at the appropriate scale. Finally, we develop a geometric framework to facilitate the interpretation of causal experiments when brain perturbations do or do not respect the intrinsic patterns of brain activity. We describe the challenges and opportunities of applying perturbations in the presence of dynamics, and we close with a general perspective on navigating the activity space of neurons in the search for neural codes.

  17. Reduction of Sodium in the NASA Space Food System

    NASA Technical Reports Server (NTRS)

    Kloeris, Vickie L.

    2010-01-01

    Excessive sodium content of the average American diet is an issue that is gaining more and more attention due to the implications for chronic disease and thus health care costs. The typical astronaut or cosmonaut dining on the International Space Station (ISS) is consuming even more sodium per day than the average American due to the lack of refrigeration for food and the limited amount of fresh food in the diet. NASA has known for many years that the high sodium in the on orbit diet is an exacerbating factor for the bone loss that occurs in all crew members in microgravity. However, bone loss is reversed upon return to earth normal gravity. After ten years of having US crewmembers on ISS, additional medical issues have emerged in some long duration ISS crewmembers that are not necessarily being reversed upon return to earth. While it is not necessarily thought that the high sodium content of the diet is the cause of these issues, it is thought that reducing sodium intake could potentially help alleviate some of the on orbit symptoms. Thus, there is an urgent focus on sodium reduction in space food. This paper will discuss the strategies and progress of an on-going project at NASA to reformulate the US space food system to reduce the sodium content.

  18. Pure state consciousness and its local reduction to neuronal space

    NASA Astrophysics Data System (ADS)

    Duggins, A. J.

    2013-01-01

    The single neuronal state can be represented as a vector in a complex space, spanned by an orthonormal basis of integer spike counts. In this model a scalar element of experience is associated with the instantaneous firing rate of a single sensory neuron over repeated stimulus presentations. Here the model is extended to composite neural systems that are tensor products of single neuronal vector spaces. Depiction of the mental state as a vector on this tensor product space is intended to capture the unity of consciousness. The density operator is introduced as its local reduction to the single neuron level, from which the firing rate can again be derived as the objective correlate of a subjective element. However, the relational structure of perceptual experience only emerges when the non-local mental state is considered. A metric of phenomenal proximity between neuronal elements of experience is proposed, based on the cross-correlation function of neurophysiology, but constrained by the association of theoretical extremes of correlation/anticorrelation in inseparable 2-neuron states with identical and opponent elements respectively.

  19. SiMPSON: Efficient Similarity Search in Metric Spaces over P2P Structured Overlay Networks

    NASA Astrophysics Data System (ADS)

    Vu, Quang Hieu; Lupu, Mihai; Wu, Sai

    Similarity search in metric spaces over centralized systems has been significantly studied in the database research community. However, not so much work has been done in the context of P2P networks. This paper introduces SiMPSON: a P2P system supporting similarity search in metric spaces. The aim is to answer queries faster and using less resources than existing systems. For this, each peer first clusters its own data using any off-the-shelf clustering algorithms. Then, the resulting clusters are mapped to one-dimensional values. Finally, these one-dimensional values are indexed into a structured P2P overlay. Our method slightly increases the indexing overhead, but allows us to greatly reduce the number of peers and messages involved in query processing: we trade a small amount of overhead in the data publishing process for a substantial reduction of costs in the querying phase. Based on this architecture, we propose algorithms for processing range and kNN queries. Extensive experimental results validate the claims of efficiency and effectiveness of SiMPSON.

  20. Quaternionic Heisenberg groups as naturally reductive homogeneous spaces

    NASA Astrophysics Data System (ADS)

    Agricola, Ilka; Ferreira, Ana Cristina; Storm, Reinier

    2015-05-01

    In this paper, we describe the geometry of the quaternionic Heisenberg groups from a Riemannian viewpoint. We show, in all dimensions, that they carry an almost 3-contact metric structure which allows us to define the metric connection that equips these groups with the structure of a naturally reductive homogeneous space. It turns out that this connection, which we shall call the canonical connection because of its analogy to the 3-Sasaki case, preserves the horizontal and vertical distributions and even the quaternionic contact (qc) structure of the quaternionic Heisenberg groups. We focus on the 7-dimensional case and prove that the canonical connection can also be obtained by means of a cocalibrated G2 structure. We then study the spinorial properties of this group and present the noteworthy fact that it is the only known example of a manifold which carries generalized Killing spinors with three different eigenvalues.

  1. Space pruning monotonic search for the non-unique probe selection problem.

    PubMed

    Pappalardo, Elisa; Ozkok, Beyza Ahlatcioglu; Pardalos, Panos M

    2014-01-01

    Identification of targets, generally viruses or bacteria, in a biological sample is a relevant problem in medicine. Biologists can use hybridisation experiments to determine whether a specific DNA fragment, that represents the virus, is presented in a DNA solution. A probe is a segment of DNA or RNA, labelled with a radioactive isotope, dye or enzyme, used to find a specific target sequence on a DNA molecule by hybridisation. Selecting unique probes through hybridisation experiments is a difficult task, especially when targets have a high degree of similarity, for instance in a case of closely related viruses. After preliminary experiments, performed by a canonical Monte Carlo method with Heuristic Reduction (MCHR), a new combinatorial optimisation approach, the Space Pruning Monotonic Search (SPMS) method, is introduced. The experiments show that SPMS provides high quality solutions and outperforms the current state-of-the-art algorithms.

  2. Space program payload costs and their possible reduction

    NASA Technical Reports Server (NTRS)

    Vanvleck, E. M.; Deerwester, J. M.; Norman, S. M.; Alton, L. R.

    1973-01-01

    The possible ways by which NASA payload costs might be reduced in the future were studied. The major historical reasons for payload costs being as they were, and if there are technologies (hard and soft), or criteria for technology advances, that could significantly reduce total costs of payloads were examined. Payload costs are placed in historical context. Some historical cost breakdowns for unmanned NASA payloads are presented to suggest where future cost reductions could be most significant. Space programs of NOAA, DoD and COMSAT are then examined to ascertain if payload reductions have been brought about by the operational (as opposed to developmental) nature of such programs, economies of scale, the ability to rely on previously developed technology, or by differing management structures and attitudes. The potential impact was investigated of NASA aircraft-type management on spacecraft program costs, and some examples relating previous costs associated with aircraft costs on the one hand and manned and unmanned costs on the other are included.

  3. Long-Term International Space Station (ISS) Risk Reduction Activities

    NASA Technical Reports Server (NTRS)

    Forroci, Michael P.; Gafka, George K.; Lutomski, Michael G.; Maher, Jacilyn S.

    2011-01-01

    As the assembly of the ISS nears completion, it is worthwhile to step back and review some of the actions pursued by the Program in recent years to reduce risk and enhance the safety and health of ISS crewmembers, visitors, and space flight participants. While the initial ISS requirements and design were intended to provide the best practicable levels of safety, it is always possible to further reduce risk given the determination, commitment, and resources to do so. The following is a summary of some of the steps taken by the ISS Program Manager, by our International Partners, by hardware and software designers, by operational specialists, and by safety personnel to continuously enhance the safety of the ISS, and to reduce risk to all crewmembers. While years of work went into the development of ISS requirements, there are many things associated with risk reduction in a Program like the ISS that can only be learned through actual operational experience. These risk reduction activities can be divided into roughly three categories: Areas that were initially noncompliant which have subsequently been brought into compliance or near compliance (i.e., Micrometeoroid and Orbital Debris [MMOD] protection, acoustics) Areas where initial design requirements were eventually considered inadequate and were subsequently augmented (i.e., Toxicity hazard level-4 materials, emergency procedures, emergency equipment, control of drag-throughs) Areas where risks were initially underestimated, and have subsequently been addressed through additional mitigation (i.e., Extravehicular Activity [EVA] sharp edges, plasma shock hazards). Due to the hard work and cooperation of many parties working together across the span of more than a decade, the ISS is now a safer and healthier environment for our crew, in many cases exceeding the risk reduction targets inherent in the intent of the original design. It will provide a safe and stable platform for utilization and discovery for years to come.

  4. Space Technology 7 Disturbance Reduction System - precision control flight Validation

    NASA Technical Reports Server (NTRS)

    Carmain, Andrew J.; Dunn, Charles; Folkner, William; Hruby, Vlad; Spence, Doug; O'Donnell, James; Markley, Landis; Maghami, Peiman; Hsu, Oscar; Demmons, N.; Roy, T.; Gasdaska, C.; Young, J.; Connolly, W.; McCormick, R.; Gasdaska, C.

    2005-01-01

    The NASA New Millennium Program Space Technology 7 (ST7) project will validate technology for precision spacecraft control. The Disturbance Reduction System (DRS) will be part of the European Space Agency's LISA Pathfinder project. The DRS will control the position of the spacecraft relative to a reference to an accuracy of one nanometer over time scales of several thousand seconds. To perform the control, the spacecraft will use a new colloid thruster technology. The thrusters will operate over the range of 5 to 30 micro-Newtons with precision of 0.1 micro- Newton. The thrust will be generated by using a high electric field to extract charged droplets of a conducting colloid fluid and accelerating them with a precisely adjustable voltage. The control reference will be provided by the European LISA Technology Package, which will include two nearly freefloating test masses. The test mass positions and orientations will be measured using a capacitance bridge. The test mass position and attitude will be adjustable using electrostatically applied forces and torques. The DRS will control the spacecraft position with respect to one test mass while minimizing disturbances on the second test mass. The dynamic control system will cover eighteen degrees of freedom: six for each of the test masses and six for the spacecraft. After launch in late 2009 to a low Earth orbit, the LISA Pathfinder spacecraft will be maneuvered to a halo orbit about the Earth-Sun L1 Lagrange point for operations.

  5. Logistics Reduction and Repurposing Technology for Long Duration Space Missions

    NASA Technical Reports Server (NTRS)

    Broyan, James Lee, Jr.; Chu, Andrew; Ewert, Michael K.

    2014-01-01

    One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items, and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by one manifest item having two purposes rather than two manifest items each having only one purpose. This paper provides the status of each of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACSs) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags for potential reuse on-orbit. Autonomous logistics management is using radio frequency identification (RFID) to track items and thus reduce crew time for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. A heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is under way. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology.

  6. Logistics Reduction and Repurposing Technology for Long Duration Space Missions

    NASA Technical Reports Server (NTRS)

    Broyan, James L.; Chu, Andrew; Ewert, Michael K.

    2014-01-01

    One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by replacing some items on the manifest. Examples include reuse of trash as radiation shielding or propellant. This paper provides the status of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACS) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station (ISS) technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags (MCTBs) for potential reuse on orbit. Autonomous logistics management (ALM) is using radio frequency identification (RFID) to track items and thus reduce crew requirements for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. Development of a heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is underway. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology

  7. On the beam direction search space in computerized non-coplanar beam angle optimization for IMRT—prostate SBRT

    NASA Astrophysics Data System (ADS)

    Rossi, Linda; Breedveld, Sebastiaan; Heijmen, Ben J. M.; Voet, Peter W. J.; Lanconelli, Nico; Aluwini, Shafak

    2012-09-01

    In a recent paper, we have published a new algorithm, designated ‘iCycle’, for fully automated multi-criterial optimization of beam angles and intensity profiles. In this study, we have used this algorithm to investigate the relationship between plan quality and the extent of the beam direction search space, i.e. the set of candidate beam directions that may be selected for generating an optimal plan. For a group of ten prostate cancer patients, optimal IMRT plans were made for stereotactic body radiation therapy (SBRT), mimicking high dose rate brachytherapy dosimetry. Plans were generated for five different beam direction input sets: a coplanar (CP) set and four non-coplanar (NCP) sets. For CP treatments, the search space consisted of 72 orientations (5° separations). The NCP CyberKnife (CK) space contained all directions available in the robotic CK treatment unit. The fully non-coplanar (F-NCP) set facilitated the highest possible degree of freedom in selecting optimal directions. CK+ and CK++ were subsets of F-NCP to investigate some aspects of the CK space. For each input set, plans were generated with up to 30 selected beam directions. Generated plans were clinically acceptable, according to an assessment of our clinicians. Convergence in plan quality occurred only after around 20 included beams. For individual patients, variations in PTV dose delivery between the five generated plans were minimal, as aimed for (average spread in V95: 0.4%). This allowed plan comparisons based on organ at risk (OAR) doses, with the rectum considered most important. Plans generated with the NCP search spaces had improved OAR sparing compared to the CP search space, especially for the rectum. OAR sparing was best with the F-NCP, with reductions in rectum DMean, V40Gy, V60Gy and D2% compared to CP of 25%, 35%, 37% and 8%, respectively. Reduced rectum sparing with the CK search space compared to F-NCP could be largely compensated by expanding CK with beams with relatively

  8. Learning Problem-Solving Rules as Search through a Hypothesis Space

    ERIC Educational Resources Information Center

    Lee, Hee Seung; Betts, Shawn; Anderson, John R.

    2016-01-01

    Learning to solve a class of problems can be characterized as a search through a space of hypotheses about the rules for solving these problems. A series of four experiments studied how different learning conditions affected the search among hypotheses about the solution rule for a simple computational problem. Experiment 1 showed that a problem…

  9. Mass Reduction: The Weighty Challenge for Exploration Space Flight

    NASA Technical Reports Server (NTRS)

    Kloeris, Vickie L.

    2014-01-01

    Meeting nutritional and acceptability requirements is critical for the food system for an exploration class space mission. However, this must be achieved within the constraints of available resources such as water, crew time, stowage volume, launch mass and power availability. ? Due to resource constraints, exploration class missions are not expected to have refrigerators or freezers for food storage, and current per person food mass must be reduced to improve mission feasibility. ? The Packaged Food Mass Reduction Trade Study (Stoklosa, 2009) concluded that the mass of the current space food system can be effectively reduced by decreasing water content of certain foods and offering nutrient dense substitutes, such as meal replacement bars and beverages. Target nutrient ranges were established based on the nutritional content of the current breakfast and lunch meals in the ISS standard menu. A market survey of available commercial products produced no viable options for meal replacement bar or beverage products. New prototypes for both categories were formulated to meet target nutrient ranges. Samples of prototype products were packaged in high barrier packaging currently used for ISS and underwent an accelerated shelf life study at 31 degC and 41 degC (50% RH) for 24 weeks. Samples were assessed at the following time points: Initial, 6 weeks, 12 weeks, and 24 weeks. Testing at each time point included the following: color, texture, water activity, acceptability, and hexanal analysis (for food bars only). Proof of concept prototypes demonstrated that meal replacement food bars and beverages can deliver a comparable macronutrient profile while reducing the overall mass when compared to the ISS Standard Menu. Future work suggestions for meal replacement bars: Reformulation to include ingredients that reduce hardness and reduce browning to increase shelf life. Micronutrient analysis and potential fortification. Sensory evaluation studies including satiety tests and

  10. Mapping the Color Space of Saccadic Selectivity in Visual Search

    ERIC Educational Resources Information Center

    Xu, Yun; Higgins, Emily C.; Xiao, Mei; Pomplun, Marc

    2007-01-01

    Color coding is used to guide attention in computer displays for such critical tasks as baggage screening or air traffic control. It has been shown that a display object attracts more attention if its color is more similar to the color for which one is searching. However, what does "similar" precisely mean? Can we predict the amount of attention…

  11. Kennedy space center cardiovascular disease risk reduction program evaluation

    PubMed Central

    Calderon, Kristine S; Smallwood, Charles; Tipton, David A

    2008-01-01

    This program evaluation examined the Kennedy Space Center (KSC) Cardiovascular Disease (CVD) Risk Reduction Program which aims to identify CVD risk factors and reduce these risk factors through health education phone counseling. High risk participants (those having two or more elevated lipid values) are identified from monthly voluntary CVD screenings and counseled. Phone counseling consists of reviewing lab values with the participant, discussing dietary fat intake frequency using an intake questionnaire, and promoting the increase in exercise frequency. The participants are followed-up at two-months and five-months for relevant metrics including blood pressure, weight, body mass index (BMI), total cholesterol, high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol, triglycerides, dietary fat intake, and exercise frequency. Data for three years of the KSC CVD Program included 366 participants, average age of 49 years, 75% male, and 25% female. For those with complete two and five month follow-up data, significant baseline to two-month follow-up comparisons included decreases in systolic blood pressure (p = 0.03); diastolic blood pressure (p = 0.002); total cholesterol, LDL cholesterol and dietary fat intake (all three at p < 0.0001) as well as a significant increase in exercise frequency (p = 0.04). Significant baseline to five-month follow-up comparisons included decreases in triglycerides (p = 0.05); and total cholesterol, LDL cholesterol and dietary intake (all three at p < 0.0001). These program evaluation results indicate that providing brief phone health education counseling and information at the worksite to high risk CVD participants may impact CVD risk factors. PMID:18561517

  12. Linking search space structure, run-time dynamics, and problem difficulty : a step toward demystifying tabu search.

    SciTech Connect

    Whitley, L. Darrell; Howe, Adele E.; Watson, Jean-Paul

    2004-09-01

    Tabu search is one of the most effective heuristics for locating high-quality solutions to a diverse array of NP-hard combinatorial optimization problems. Despite the widespread success of tabu search, researchers have a poor understanding of many key theoretical aspects of this algorithm, including models of the high-level run-time dynamics and identification of those search space features that influence problem difficulty. We consider these questions in the context of the job-shop scheduling problem (JSP), a domain where tabu search algorithms have been shown to be remarkably effective. Previously, we demonstrated that the mean distance between random local optima and the nearest optimal solution is highly correlated with problem difficulty for a well-known tabu search algorithm for the JSP introduced by Taillard. In this paper, we discuss various shortcomings of this measure and develop a new model of problem difficulty that corrects these deficiencies. We show that Taillard's algorithm can be modeled with high fidelity as a simple variant of a straightforward random walk. The random walk model accounts for nearly all of the variability in the cost required to locate both optimal and sub-optimal solutions to random JSPs, and provides an explanation for differences in the difficulty of random versus structured JSPs. Finally, we discuss and empirically substantiate two novel predictions regarding tabu search algorithm behavior. First, the method for constructing the initial solution is highly unlikely to impact the performance of tabu search. Second, tabu tenure should be selected to be as small as possible while simultaneously avoiding search stagnation; values larger than necessary lead to significant degradations in performance.

  13. Children's search behaviour in large-scale space: developmental components of exploration.

    PubMed

    Smith, Alastair D; Gilchrist, Iain D; Hood, Bruce M

    2005-01-01

    It has been argued that visual-search tasks provide a valid model for foraging behaviour. However, Gilchrist et al (2001 Perception 30 1459-1464) demonstrated that, whilst some aspects of behaviour transferred to large-scale egocentric search, there were substantially fewer revisits to previously searched locations than would be expected from the visual-search literature. This difference might be a result of the greater effort required to search in a large-scale egocentric context. Here, we present a novel, automated paradigm, for examining the effect of effort on egocentric search behaviour by manipulating the motor difficulty of the task. Children searched for a hidden target amongst a randomised display of lights by activating a switch at each potential location. The motor difficulty of the task was manipulated by requiring children to search with either their dominant or their nondominant hand. We found that when children searched with their nondominant hand, they made significantly more revisits to previously checked locations than they did when using their dominant hand. This suggests that, when the motor response was more effortful, children were less able to efficiently guide their search behaviour. Individuals with a greater visuo-spatial short-term memory span performed the task more quickly than those with a lower span. However, search latencies were unrelated to general fluid intelligence. This highlights the role of spatial working memory in the development of efficient exploration of large-scale space.

  14. Searching for Clinical Evidence in CiteSpace

    PubMed Central

    Chen, Chaomei; Chen, Yunan

    2005-01-01

    A crucial step in the practice of evidence-based medicine is to locate the best available evidence regarding to clinical questions. In this article, we demonstrate that combining visualization techniques with traditional methods developed in evidence-based medicine could simplify the task. We describe a unifying framework for searching clinical evidence across multiple sources such as highly cited articles in the Web of Science and articles of particular types of study design in PubMed. We describe the implementation of a prototyping system to visualize the distribution of available evidence in a broader context of the underlying subject domain. We include examples of evidence found in the heart diseases and lung cancer literature. Practical implications on the design of visualization-based evidence searching tools are discussed. PMID:16779014

  15. Search and Determine Integrated Environment (SADIE) for Space Situational Awareness

    DTIC Science & Technology

    2012-09-01

    Sabol 1 , Alan Segerman 2 , Aaron Hoskins 2 , Bryan Little 1 , Paul W. Schumacher Jr. 1 , Shannon Coffey 2 1 Air Force Research Laboratory...Directed Energy Directorate; Kihei, HI 2 Naval Research Laboratory; Washington, DC ABSTRACT A new high performance computing software applications...package called the Search and Determine Integrated Environment (SADIE) is being jointly developed and refined by the Air Force and Naval Research

  16. A search for experiments to exploit the space shuttle environment, volume 2

    NASA Technical Reports Server (NTRS)

    Fenn, J. B.

    1979-01-01

    Institutions and laboratories in India, Japan, and Western Europe which were visited during a search for experiments to exploit the space shuttle environment are described. The facilities and current research interests of the various centers are discussed with particular emphasis given to the Indian Space Research Organization.

  17. Determining frequentist confidence limits using a directed parameter space search

    SciTech Connect

    Daniel, Scott F.; Connolly, Andrew J.; Schneider, Jeff

    2014-10-10

    We consider the problem of inferring constraints on a high-dimensional parameter space with a computationally expensive likelihood function. We propose a machine learning algorithm that maps out the Frequentist confidence limit on parameter space by intelligently targeting likelihood evaluations so as to quickly and accurately characterize the likelihood surface in both low- and high-likelihood regions. We compare our algorithm to Bayesian credible limits derived by the well-tested Markov Chain Monte Carlo (MCMC) algorithm using both multi-modal toy likelihood functions and the seven yr Wilkinson Microwave Anisotropy Probe cosmic microwave background likelihood function. We find that our algorithm correctly identifies the location, general size, and general shape of high-likelihood regions in parameter space while being more robust against multi-modality than MCMC.

  18. Space telescope searches for black holes in galactic nuclei

    NASA Technical Reports Server (NTRS)

    Harms, Richard J.

    1989-01-01

    The Hubble Space Telescope (HST) will allow astronomers to obtain luminosity profiles, rotation curves, and velocity dispersions at angular scales that are an order of magnitude superior to those obtained previously. This enhanced spatial resolution will greatly improve the sensitivity for detecting centrally condensed matter in nearby galactic nuclei including, possibly, black holes.

  19. Teacher Education Physical Education: In Search of a Hybrid Space

    ERIC Educational Resources Information Center

    Lynch, Timothy

    2015-01-01

    It is argued that a learning environment underpinned by a strengths-based collaborative approach between universities and schools offers extended pre-service teacher learning opportunities and subsequently enhanced preparation. The term "hybrid space" describes the ideal environment of shared partnership where knowledge is jointly…

  20. Deep Space Detectives: Searching for Planets Suitable for Life

    ERIC Educational Resources Information Center

    Pallant, Amy; Damelin, Daniel; Pryputniewicz, Sarah

    2013-01-01

    This article describes the High-Adventure Science curriculum unit "Is There Life in Space?" This free online investigation, developed by The Concord Consortium, helps students see how scientists use modern tools to locate planets around distant stars and explore the probability of finding extraterrestrial life. This innovative curriculum…

  1. The Space Physics Archive Search and Extract (SPASE) Project: Glue for Interoperability

    NASA Astrophysics Data System (ADS)

    Thieman, J. R.; King, J.; Roberts, A.; King, T.; Rezapkin, V.

    2005-05-01

    The Space Physics Archive Search and Extract (SPASE) Project is a NASA-funded, collaborative development effort among multi-institution, international, space physics data holding organizations intended to allow science users to interoperably locate space physics data of interest, intercompare the information about data, and retrieve selected data sets or portions of data sets. Presently this consortium is continuing to update the SPASE Data Model (see http://www.igpp.ucla.edu/spase/) as a common metadata language for searching across the multitude of disparate data archives for data of interest. The model is being applied to data set descriptions for the important data holdings of the participating institutions. Searching via SPASE-compliant interfaces generates a query using the common metadata language. The query is translated into local search terminology at each relevant space physics data center. Search results are then gathered and displayed to the user in a common format. Thus, there is no need to change the software and search procedures used at the individual institutions. The model is intended to support data description at multiple levels of detail.JosephTodd Data set intercomparisons will enable determination of which data are useful for the purposes of the scientist/user. We are working with the Virtual Observatories relevant to space physics to enable data searching, access, and retrieval from these unifying theme portals. An example interface is available at the Virtual Space Physics Observatory (VSPO) through the following URL: http://vspo.gsfc.nasa.gov/websearch/dispatcher Development of an effective Data Model is challenging and requires feedback from all sectors of the community. We welcome new participants and discussion of the SPASE activities with the authors either in the session or in future SPASE teleconferences, presentations, or related meetings.

  2. Risk Reduction for Use of Complex Devices in Space Projects

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Poivey, Christian; Friendlich, Mark; Petrick, Dave; LaBel, Kenneth; Stansberry, Scott

    2007-01-01

    We present guidel!nes to reduce risk to an acceptable level when using complex devices in space applications. Application to Virtex 4 Field Programmable Gate Array (FPGA) on Express Logistic Carrier (ELC) project is presented.

  3. Search and Rescue in Space Activities: Is There a Specific Legal Regime?

    NASA Astrophysics Data System (ADS)

    Kyriakopoulos, George D.

    2013-09-01

    As space exploration has always been a dangerous activity, this paper examines if a "space" search and rescue regime can validly be claimed to exist. Regarding vessels in distress, the Hamburg Convention provided for SAR regions "by way of mutual regional arrangements" between States. Regarding aircraft in distress, specific SAR Regions have been established, in conformity with Annex 12 to the Chicago Convention. In space, art. V of the OST, if broadly interpreted, could be applied to "space-to space" rescue operations. This principle is further elaborated by the Rescue Agreement, although the latter does not apply in "deep space" distress situations. Finally, The Moon Agreement applies this framework to "Persons on the Moon". It follows that Space Law provides for SAR operations on the level of principle, as no integrated legal regime seems to exist. Therefore, the Air/Sea SAR regimes could serve as models for a comprehensive space regulation.

  4. Searching for impact craters using space shuttle photography

    NASA Technical Reports Server (NTRS)

    Wood, C. A.; Dailey, C.; Daley, W.; Wells, G.

    1984-01-01

    Extrapolation of impact cratering rates derived from Canada and Europe suggests that in the cratonic regions of Australia, India, Africa, and Brazil, 14-15 impact craters 20 km diameter should have formed during the last 120 my, and survived erosional erasure. In fact, in these areas, only 2 craters are known that approximately qualify: (1) Gosses Bluff, 22 km, 130 + or - 6 my old, and; Strangways, 24 km and 150 + or - 70 my old. It is therefore likely that about a dozen relatively large and preserved impact craters await discovery in these less explored cratons. A larger number of younger and smaller craters must also exist. An informal search is reported for impact craters using photographs obtained by Shuttle astronauts. Photographs taken with the 250 mm lens on Hassalblad cameras have a resolution of 25 m and cover a nominal area of 50x60 sq km. A larger format Linhof camera with similar resolution but 4 times larger area was flown March 1984, and will fly again in the future. Shuttle imagery has numerous advantages in looking for impact craters and for other types of Earth observations.

  5. An Algorithm for Constructing and Searching Spaces of Alternative Hypotheses

    SciTech Connect

    Testa, Kelly M; Griffin, Christopher H

    2011-01-01

    In this paper, we develop techniques for automated hypothesis-space exploration over data sets that may contain contradictions. To do so, we make use of the equivalence between two formulations: those of first-order predicate logic with prefix modal quantifiers under the finite-model hypothesis and those of mixed-integer linear programming (MILP) problems. Unlike other approaches, we do not assume that all logical assertions are true without doubt. Instead, we look for alternative hypotheses about the validity of the claims by identifying alternative optimal solutions to a corresponding MILP. We use a collection of slack variables in the derived linear constraints to indicate the presence of contradictory data or assumptions. The objective is to minimize contradictions between data and assertions represented by the presence of nonzero slack in the set of linear constraints. In this paper, we present the following: 1) a correspondence between first-order predicate logic with modal quantifier prefixes under the finite-model hypothesis and MILP problems and 2) an implicit enumeration algorithm for exploring the contradiction hypothesis space.

  6. Recycling and source reduction for long duration space habitation

    NASA Technical Reports Server (NTRS)

    Hightower, T. M.

    1992-01-01

    A direct mathematical approach has been established for characterizing the performance of closed-loop life support systems. The understanding that this approach gives clearly illustrates the options available for increasing the performance of a life support system by changing various parameters. New terms are defined and utilized, such as Segregation Factor, Resource Recovery Efficiency, Overall Reclamation Efficiency, Resupply Reduction Factor, and Life Support Extension Factor. The effects of increases in expendable system supplies required due to increases in life support system complexity are shown. Minimizing resupply through increased recycling and source reduction is illustrated. The effects of recycling upon resupply launch cost is also shown. Finally, material balance analyses have been performed based on quantity and composition data for both supplies and wastes, to illustrate the use of this approach by comparing ten different closed-loop life support system cases.

  7. Federated Space-Time Query for Earth Science Data Using OpenSearch Conventions

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris; Beaumont, Bruce; Duerr, Ruth; Hua, Hook

    2009-01-01

    This slide presentation reviews a Space-time query system that has been developed to assist the user in finding Earth science data that fulfills the researchers needs. It reviews the reasons why finding Earth science data can be so difficult, and explains the workings of the Space-Time Query with OpenSearch and how this system can assist researchers in finding the required data, It also reviews the developments with client server systems.

  8. The ALPHA Magnetic Spectrometer for the Search of Cosmic Antimatter in Space

    NASA Astrophysics Data System (ADS)

    Wallraff, W.

    1997-02-01

    The apparent absence of antimatter (anti-helium, anti-carbon, etc.) in the universe is a major puzzle of particle physics. The ALPHA Magnetic Spectrometer AMS is a high resolution tracking detector under construction. It will improve the sensitivity for antimatter search by a factor of more than 104. For more than 3 years AMS will sample cosmic rays in space while orbiting around earth on the international space station ISSA.

  9. SeekAView: An Intelligent Dimensionality Reduction Strategy for Navigating High-Dimensional Data Spaces

    SciTech Connect

    Krause, Josua; Dasgupta, Aritra; Fekete, Jean-Daniel; Bertini, Enrico

    2016-10-23

    Dealing with the curse of dimensionality is a key challenge in high-dimensional data visualization. We present SeekAView to address three main gaps in the existing research literature. First, automated methods like dimensionality reduction or clustering suffer from a lack of transparency in letting analysts interact with their outputs in real-time to suit their exploration strategies. The results often suffer from a lack of interpretability, especially for domain experts not trained in statistics and machine learning. Second, exploratory visualization techniques like scatter plots or parallel coordinates suffer from a lack of visual scalability: it is difficult to present a coherent overview of interesting combinations of dimensions. Third, the existing techniques do not provide a flexible workflow that allows for multiple perspectives into the analysis process by automatically detecting and suggesting potentially interesting subspaces. In SeekAView we address these issues using suggestion based visual exploration of interesting patterns for building and refining multidimensional subspaces. Compared to the state-of-the-art in subspace search and visualization methods, we achieve higher transparency in showing not only the results of the algorithms, but also interesting dimensions calibrated against different metrics. We integrate a visually scalable design space with an iterative workflow guiding the analysts by choosing the starting points and letting them slice and dice through the data to find interesting subspaces and detect correlations, clusters, and outliers. We present two usage scenarios for demonstrating how SeekAView can be applied in real-world data analysis scenarios.

  10. Bioastronautics Roadmap: A Risk Reduction Strategy for Human Space Exploration

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The Bioastronautics Critical Path Roadmap is the framework used to identify and assess the risks to crews exposed to the hazardous environments of space. It guides the implementation of research strategies to prevent or reduce those risks. Although the BCPR identifies steps that must be taken to reduce the risks to health and performance that are associated with human space flight, the BCPR is not a "critical path" analysis in the strict engineering sense. The BCPR will evolve to accommodate new information and technology development and will enable NASA to conduct a formal critical path analysis in the future. As a management tool, the BCPR provides information for making informed decisions about research priorities and resource allocation. The outcome-driven nature of the BCPR makes it amenable for assessing the focus, progress and success of the Bioastronautics research and technology program. The BCPR is also a tool for communicating program priorities and progress to the research community and NASA management.

  11. Is It Time for Space Debris Reduction Capabilities?

    DTIC Science & Technology

    2009-04-01

    thrown into a range of orbits of varying altitudes).3 Thus, it appears the space debris problem is increasing. With this increase in orbital debris , we...and geostationary orbit (the fixed point over equator providing widest coverage of Earth).4 Spacecraft and orbital debris travelling in low earth...all orbital debris up to an altitude of 800 km in two years” for about $100 to 200M.98 The team also recommended a technical demonstration study to

  12. Optimal Scheme for Search State Space and Scheduling on Multiprocessor Systems

    NASA Astrophysics Data System (ADS)

    Youness, Hassan A.; Sakanushi, Keishi; Takeuchi, Yoshinori; Salem, Ashraf; Wahdan, Abdel-Moneim; Imai, Masaharu

    A scheduling algorithm aims to minimize the overall execution time of the program by properly allocating and arranging the execution order of the tasks on the core processors such that the precedence constraints among the tasks are preserved. In this paper, we present a new scheduling algorithm by using geometry analysis of the Task Precedence Graph (TPG) based on A* search technique and uses a computationally efficient cost function for guiding the search with reduced complexity and pruning techniques to produce an optimal solution for the allocation/scheduling problem of a parallel application to parallel and multiprocessor architecture. The main goal of this work is to significantly reduce the search space and achieve the optimality or near optimal solution. We implemented the algorithm on general task graph problems that are processed on most of related search work and obtain the optimal scheduling with a small number of states. The proposed algorithm reduced the exhaustive search by at least 50% of search space. The viability and potential of the proposed algorithm is demonstrated by an illustrative example.

  13. Multidimensional scaling for evolutionary algorithms--visualization of the path through search space and solution space using Sammon mapping.

    PubMed

    Pohlheim, Hartmut

    2006-01-01

    Multidimensional scaling as a technique for the presentation of high-dimensional data with standard visualization techniques is presented. The technique used is often known as Sammon mapping. We explain the mathematical foundations of multidimensional scaling and its robust calculation. We also demonstrate the use of this technique in the area of evolutionary algorithms. First, we present the visualization of the path through the search space of the best individuals during an optimization run. We then apply multidimensional scaling to the comparison of multiple runs regarding the variables of individuals and multi-criteria objective values (path through the solution space).

  14. The Anti-Matter Spectrometer for high sensitivity searches of anti-nuclei in space.

    NASA Astrophysics Data System (ADS)

    Wallraff, W.

    The apparent absence of antimatter (anti-helium, anti-carbon, etc.) in the universe is a major puzzle of particle physics. The Anti-Matter Spectrometer is a high resolution tracking detector under construction, that will improve the sensitivity for antimatter searches by a factor of more than 104, while orbiting around the Earth on the space station ISSA for >3 years.

  15. Parameter-space metric of semicoherent searches for continuous gravitational waves

    NASA Astrophysics Data System (ADS)

    Pletsch, Holger J.

    2010-08-01

    Continuous gravitational-wave (CW) signals such as emitted by spinning neutron stars are an important target class for current detectors. However, the enormous computational demand prohibits fully coherent broadband all-sky searches for prior unknown CW sources over wide ranges of parameter space and for yearlong observation times. More efficient hierarchical “semicoherent” search strategies divide the data into segments much shorter than one year, which are analyzed coherently; then detection statistics from different segments are combined incoherently. To optimally perform the incoherent combination, understanding of the underlying parameter-space structure is requisite. This problem is addressed here by using new coordinates on the parameter space, which yield the first analytical parameter-space metric for the incoherent combination step. This semicoherent metric applies to broadband all-sky surveys (also embedding directed searches at fixed sky position) for isolated CW sources. Furthermore, the additional metric resolution attained through the combination of segments is studied. From the search parameters (sky position, frequency, and frequency derivatives), solely the metric resolution in the frequency derivatives is found to significantly increase with the number of segments.

  16. Heuristics in Problem Solving: The Role of Direction in Controlling Search Space

    ERIC Educational Resources Information Center

    Chu, Yun; Li, Zheng; Su, Yong; Pizlo, Zygmunt

    2010-01-01

    Isomorphs of a puzzle called m+m resulted in faster solution times and an easily reproduced solution path in a labeled version of the problem compared to a more difficult binary version. We conjecture that performance is related to a type of heuristic called direction that not only constrains search space in the labeled version, but also…

  17. A learning heuristic for space mapping and searching self-organizing systems using adaptive mesh refinement

    NASA Astrophysics Data System (ADS)

    Phillips, Carolyn L.

    2014-09-01

    In a complex self-organizing system, small changes in the interactions between the system's components can result in different emergent macrostructures or macrobehavior. In chemical engineering and material science, such spontaneously self-assembling systems, using polymers, nanoscale or colloidal-scale particles, DNA, or other precursors, are an attractive way to create materials that are precisely engineered at a fine scale. Changes to the interactions can often be described by a set of parameters. Different contiguous regions in this parameter space correspond to different ordered states. Since these ordered states are emergent, often experiment, not analysis, is necessary to create a diagram of ordered states over the parameter space. By issuing queries to points in the parameter space (e.g., performing a computational or physical experiment), ordered states can be discovered and mapped. Queries can be costly in terms of resources or time, however. In general, one would like to learn the most information using the fewest queries. Here we introduce a learning heuristic for issuing queries to map and search a two-dimensional parameter space. Using a method inspired by adaptive mesh refinement, the heuristic iteratively issues batches of queries to be executed in parallel based on past information. By adjusting the search criteria, different types of searches (for example, a uniform search, exploring boundaries, sampling all regions equally) can be flexibly implemented. We show that this method will densely search the space, while preferentially targeting certain features. Using numerical examples, including a study simulating the self-assembly of complex crystals, we show how this heuristic can discover new regions and map boundaries more accurately than a uniformly distributed set of queries.

  18. Flexible space structure model reduction by modal cost analysis

    NASA Technical Reports Server (NTRS)

    Skelton, R. E.; Hughes, P. C.

    1979-01-01

    It is noted that reduced models and reduced controllers for flexible space structures are obtained by retaining those modes which make the greatest contribution to quadratic control objectives. Attention is given to the relative importance of damping, frequency and mode shapes in the mode truncation decisions for the following control objectives: attitude control, vibration suppression and figure control. It is also shown that using Modal Cost Analysis (MCA) on the closed loop modes of the optimally controlled system allows the construction of reduced control policies which feedback only those closed loop coordinates which are most critical to the quadratic control performance criterion. In this manner, the modes which need to be controlled are deduced from truncations of the optimal controller.

  19. Exhaustive geographic search with mobile robots along space-filling curves

    SciTech Connect

    Spires, S.V.; Goldsmith, S.Y.

    1998-03-01

    Swarms of mobile robots can be tasked with searching a geographic region for targets of interest, such as buried land mines. The authors assume that the individual robots are equipped with sensors tuned to the targets of interest, that these sensors have limited range, and that the robots can communicate with one another to enable cooperation. How can a swarm of cooperating sensate robots efficiently search a given geographic region for targets in the absence of a priori information about the target`s locations? Many of the obvious approaches are inefficient or lack robustness. One efficient approach is to have the robots traverse a space-filling curve. For many geographic search applications, this method is energy-frugal, highly robust, and provides guaranteed coverage in a finite time that decreases as the reciprocal of the number of robots sharing the search task. Furthermore, it minimizes the amount of robot-to-robot communication needed for the robots to organize their movements. This report presents some preliminary results from applying the Hilbert space-filling curve to geographic search by mobile robots.

  20. The Search for Dark Matter with the Fermi Gamma Ray Space Telescope

    SciTech Connect

    Bloom, Elliott

    2011-03-30

    The Fermi Gamma-Ray Space Telescope has been scanning the gamma ray sky since it was launched by NASA in June 2008 and has a mission lifetime goal of 10 years. Largely due to our particle physics heritage, one of the main physics topics being studied by the Fermi LAT Collaboration is the search for dark matter via indirect detection. My talk will review the progress of these studies, something on how the LAT detector enables them, and expectations for the future. I will discuss both gamma-ray and (electron + positron) searches for dark matter, and some resulting theoretical implications.

  1. Results of a hubble space telescope search for natural satellites of dwarf planet 1 ceres

    NASA Astrophysics Data System (ADS)

    DeMario, Benjamin E.; Schmidt, Britney E.; Mutchler, Max J.; Li, Jian-Yang; McFadden, Lucy A.; McLean, Brian J.; Russell, Christopher T.

    2016-12-01

    In order to prepare for the arrival of the Dawn spacecraft at Ceres, a search for satellites was undertaken by the Hubble Space Telescope (HST) to enhance the mission science return and to ensure spacecraft safety. Previous satellite searches from ground-based telescopes have detected no satellites within Ceres' Hill sphere down to a size of 3 km (Gehrels et al. 1987) and early HST investigations searched to a limit of 1-2 km (Bieryla et al. 2011). The Wide Field Camera 3 (WFC3) on board the HST was used to image Ceres between 14 April-28 April 2014. These images cover approximately the inner third of Ceres' Hill sphere, where the Hill sphere is the region surrounding Ceres where stable satellite orbits are possible. We performed a deep search for possible companions orbiting Ceres. No natural companions were located down to a diameter of 48 m, over most of the Hill sphere to a distance of 205,000 km (434 Ceres radii) from the surface of Ceres. It was impossible to search all the way to the surface of Ceres because of scattered light, but at a distance of 2865 km (five Ceres radii), the search limit was determined to be 925 m.

  2. Results of a Hubble Space Telescope Search for Natural Satellites of Dwarf Planet 1 Ceres

    NASA Astrophysics Data System (ADS)

    DeMario, Benjamin; Schmidt, Britney E.; Mutchler, Maximilian J.; Li, Jian-Yang; McFadden, Lucy Ann; McLean, Brian; Russell, Christopher T.

    2016-10-01

    In order to prepare for the arrival of the Dawn spacecraft at Ceres, a search for satellites was undertaken by the Hubble Space Telescope (HST) to enhance the mission science return and to ensure spacecraft safety. Previous satellite searches from ground-based telescopes have detected no satellites within Ceres' Hill sphere down to a size of 3 km (Gehrels et al. 1987) and early HST investigations searched to a limit of 1-2 km (Bieryla et al. 2011). The Wide Field Camera 3 (WFC3) on board the HST was used to image Ceres between 14 April - 28 April 2014. These images cover approximately the inner third of Ceres' Hill sphere, where the Hill sphere is the region surrounding Ceres where stable satellite orbits are possible. We performed a deep search for possible companions orbiting Ceres. No natural companions were located down to a diameter of 48 meters, over most of the Hill sphere to a distance of 205,000 km (434 Ceres radii) from the surface of Ceres. It was impossible to search all the way to the surface of Ceres because of scattered light, but at a distance of 2865 km (five Ceres radii), the search limit was determined to be 925 meters. The absence of a satellite around Ceres could, in the future, support more refined theories about satellite formation or capture mechanisms in the solar system.

  3. Metamodel-based global optimization using fuzzy clustering for design space reduction

    NASA Astrophysics Data System (ADS)

    Li, Yulin; Liu, Li; Long, Teng; Dong, Weili

    2013-09-01

    High fidelity analysis are utilized in modern engineering design optimization problems which involve expensive black-box models. For computation-intensive engineering design problems, efficient global optimization methods must be developed to relieve the computational burden. A new metamodel-based global optimization method using fuzzy clustering for design space reduction (MGO-FCR) is presented. The uniformly distributed initial sample points are generated by Latin hypercube design to construct the radial basis function metamodel, whose accuracy is improved with increasing number of sample points gradually. Fuzzy c-mean method and Gath-Geva clustering method are applied to divide the design space into several small interesting cluster spaces for low and high dimensional problems respectively. Modeling efficiency and accuracy are directly related to the design space, so unconcerned spaces are eliminated by the proposed reduction principle and two pseudo reduction algorithms. The reduction principle is developed to determine whether the current design space should be reduced and which space is eliminated. The first pseudo reduction algorithm improves the speed of clustering, while the second pseudo reduction algorithm ensures the design space to be reduced. Through several numerical benchmark functions, comparative studies with adaptive response surface method, approximated unimodal region elimination method and mode-pursuing sampling are carried out. The optimization results reveal that this method captures the real global optimum for all the numerical benchmark functions. And the number of function evaluations show that the efficiency of this method is favorable especially for high dimensional problems. Based on this global design optimization method, a design optimization of a lifting surface in high speed flow is carried out and this method saves about 10 h compared with genetic algorithms. This method possesses favorable performance on efficiency, robustness

  4. The search for high-redshift supernovae and the image reduction

    NASA Astrophysics Data System (ADS)

    Kim, Matthew Yongsok

    1999-11-01

    The absolute peak magnitudes of Type Ia supernovae are tightly bound and their small variation shows a strong correlation with their lightcurve widths and spectral features. This correlation can be used to calibrate Type Ia supernovae peak magnitudes, making Type Ia supernovae one of the most powerful cosmological distance indicators. The Supernova Cosmology Project has developed a new search technique for detecting Type Ia supernovae at high redshift and found more than 70 supernovae at 0.3 < z < 1.2. We have used these high-redshift Type Ia supernovae to measure the cosmological parameters, ΩM, and ΩΛ , of the standard big bang model. By analyzing the redshift-apparent brightness relationship on a sample of the first 42 supernovae at 0.3 < z < .85, we have succeeded in putting a significant constraint, on the cosmological parameters. In this paper, I will discuss our supernova detection technique and the image reduction process we have used in our project.

  5. The MCELS Data Reduction Pipeline and Its Application to PNe Searches in the LMC

    NASA Astrophysics Data System (ADS)

    Paredes, L.; Points, S. D.; Smith, R. C.; Rest, A.; Damke, G.; Zenteno, A.; MCELS Team

    2015-05-01

    The Magellanic Cloud Emission-Line Survey (MCELS) obtained observations toward the Large and Small Magellanic Clouds (LMC and SMC, respectively) over six years using the UM/CTIO Curtis Schmidt 0.61m telescope to produce deep images in [O III], H-alpha, and [S II] emission-lines, in addition to adjacent green and red continuum filters. This survey covered the central 8°x8° of the LMC and the central 3.5°x4.5° of the SMC and encompasses most of the gaseous extent of each galaxy with an angular resolution of 5 arcsec or better, allowing us to identify and study interstellar structures on ˜1-1000 pc physical scales. We have modified the SuperMACHO/Essence-w pipeline, developed for Blanco 4m Mosaic II data, to reduce MCELS data in a uniform manner. In addition to basic reductions (e.g., bias-subtraction, flat-fielding, etc), this pipeline uses spatially-varying convolution kernels to match the PSFs of the narrow-band and broad-band images and produce continuum-subtracted images for the narrow-band filters. We use flux measurements of previously identified planetary nebulae (PNe) in the LMC, e.g. Reid & Parker (2010), and photometry obtained by our pipeline to create color-magnitude and color-color diagrams in the MCELS filters to search for new PNe candidates in the LMC.

  6. Space life sciences: search for signatures of life, and space flight environmental effects on the nervous system.

    PubMed

    2004-01-01

    This volume contains selected papers of the Joint COSPAR-IAC event "Search for signatures of life in the solar system, terrestrial analogues and simulation experiments" held during the World Space Congress 2002 in Houston, Texas, USA. The first section of the volume reports on the rich variety of terrestrial microbial communities adapted to extreme environments, such as microbial life at very low temperatures in permafrost and ice layers, at high salt concentrations, as inhabitants of rocks and the microbial recolonization of impact-shocked rocks. These communities are suggested to serve as analogues for extraterrestrial habitats, which are also described in this section. The second section deals with the detection of biomarkers and signatures from extinct life on Earth, which might provide clues for detection of potential extraterrestrial biomarkers. This section is followed by reports of experiments in space and in the laboratory simulating space conditions, such as the prebiotic organic chemistry, the chemistry of dust particles to be detected during the Cassini mission to Saturn, as well as the photochemistry of biological systems exposed to space or planetary surface conditions. The second part of the issue contains papers from the session "The nervous system: space flight environmental factors effects--present results and new perspectives." The presentations in this session explored various aspects of the effects of exposure to protons and heavy particles on central nervous system function and on behavior. The second series of papers examines the effects of exposure to heavy particles and protons on neurochemistry and on behavior.

  7. Integrating space and time in visual search: how the preview benefit is modulated by stereoscopic depth.

    PubMed

    Dent, Kevin; Braithwaite, Jason J; He, Xun; Humphreys, Glyn W

    2012-07-15

    We examined visual search for letters that were distributed across both 3 dimensional space, and time. In Experiment 1, when participants had foreknowledge of the depth plane and time interval where targets could appear, search was more efficient if the items could be segmented either by depth or by time (with a 1000 ms preview), and there were increased benefits when the two cues (depth and time) were combined. In Experiments 2 and 3 the target depth plane was always unknown to the participant. In this case, depth cues alone did not facilitate search, though they continued to increase the preview benefit. In Experiment 4 new items in preview search could fall at the same depth as preview items or a new depth. There was a substantial cost to search if the target appeared at a previewed depth. Experiment 5 showed that this cost remained even when participants knew the target would appear at the old depth on 75% of trials. The results indicate that spatial (depth) and temporal cues combine to enhance visual segmentation and selection, and this is accomplished by inhibition of distractors in irrelevant depth planes.

  8. Noise reduction evaluation of grids in a supersonic air stream with application to Space Shuttle

    NASA Technical Reports Server (NTRS)

    Seiner, J. M.; Manning, J. C.; Nystrom, P.; Pao, S. P.

    1977-01-01

    Near field acoustic measurements were obtained for a model supersonic air jet perturbed by a screen. Noise reduction potential in the vicinity of the space shuttle vehicle during ground launch when the rocket exhaust flow is perturbed by a grid was determined. Both 10 and 12 mesh screens were utilized for this experiment, and each exhibited a noise reduction only at very low frequencies in the near field forward arc. A power spectrum analysis revealed that a modest reduction of from 3 to 5 decibels exists below a Strouhal number S sub t = 0.11. Above S sub t = 0.11 screen harmonics increased the observed sound pressure level. The favorable noise reductions obtained with screens for S sub t 0.11 may be of substantial interest for the space shuttle at ground launch.

  9. The Space Shuttle Decision: NASA's Search for a Reusable Space Vehicle

    NASA Technical Reports Server (NTRS)

    Heppenheimer, T. A.

    1999-01-01

    This significant new study of the decision to build the Space Shuttle explains the Shuttle's origins and early development. In addition to internal NASA discussions, this work details the debates in the late 1960s and early 1970s among policymakers in Congress, the Air Force, and the Office of Management and Budget over the roles and technical designs of the Shuttle. Examining the interplay of these organizations with sometimes conflicting goals, the author not only explains how the world's premier space launch vehicle came into being, but also how politics can interact with science, technology, national security, and economics in national government. The weighty policy decision to build the Shuttle represents the first component of the broader story: future NASA volumes will cover the Shuttle's development and operational histories.

  10. Search for space charge effects in the ICARUS T600 LAr-TPC

    NASA Astrophysics Data System (ADS)

    Torti, Marta

    2016-11-01

    Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The presence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), recording cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown.

  11. Target-distractor similarity has a larger impact on visual search in school-age children than spacing.

    PubMed

    Huurneman, Bianca; Boonstra, F Nienke

    2015-01-22

    In typically developing children, crowding decreases with increasing age. The influence of target-distractor similarity with respect to orientation and element spacing on visual search performance was investigated in 29 school-age children with normal vision (4- to 6-year-olds [N = 16], 7- to 8-year-olds [N = 13]). Children were instructed to search for a target E among distractor Es (feature search: all flanking Es pointing right; conjunction search: flankers in three orientations). Orientation of the target was manipulated in four directions: right (target absent), left (inversed), up, and down (vertical). Spacing was varied in four steps: 0.04°, 0.5°, 1°, and 2°. During feature search, high target-distractor similarity had a stronger impact on performance than spacing: Orientation affected accuracy until spacing was 1°, and spacing only influenced accuracy for identifying inversed targets. Spatial analyses showed that orientation affected oculomotor strategy: Children made more fixations in the "inversed" target area (4.6) than the vertical target areas (1.8 and 1.9). Furthermore, age groups differed in fixation duration: 4- to 6-year-old children showed longer fixation durations than 7- to 8-year-olds at the two largest element spacings (p = 0.039 and p = 0.027). Conjunction search performance was unaffected by spacing. Four conclusions can be drawn from this study: (a) Target-distractor similarity governs visual search performance in school-age children, (b) children make more fixations in target areas when target-distractor similarity is high, (c) 4- to 6-year-olds show longer fixation durations than 7- to 8-year-olds at 1° and 2° element spacing, and (d) spacing affects feature but not conjunction search-a finding that might indicate top-down control ameliorates crowding in children.

  12. A theorem on the Schwartz space of a reductive Lie group

    PubMed Central

    Arthur, James

    1975-01-01

    The purpose of this paper is to define the Fourier transform of an arbitrary tempered distribution on a reductive Lie group. To this end we define a topological vector space, [unk](Ĝ), in terms of the classes of irreducible unitary representations of G, which plays role of a dual Schwartz space. Our main theorem then asserts that the usual L2 Fourier transform, when restricted to functions in the Schwartz space, [unk](G) defined by Harish-Chandra, provides a topological isomorphism from [unk](G) onto [unk](Ĝ). PMID:16592293

  13. The impact of plants on the reduction of volatile organic compounds in a small space.

    PubMed

    Song, Jeong-Eun; Kim, Yong-Shik; Sohn, Jang-Yeul

    2007-11-01

    This study aims at examining the reduction of indoor air contaminants by plants placed in an indoor space. Field measurements were performed using Aglaonema brevispathum, Pachira aquatica, and Ficus benjamiana, which were verified as air-purifying plants by NASA. Three conditions for the amount of plants and positions were used in two separate rooms whose dimensions are identical. The concentration of Volatile Organic Compounds (VOCs) was monitored three hours after the plants were placed and three days after the plants were placed. The variations of concentration of Benzene, Toluene, Etylbenzene, and Xylene (BTEX), as well as Formaldehyde, which are all known as the major elements of Volatile Organic Compounds were monitored. The amount of reduction in concentration of Toluene and Formaldehyde was monitored 3 hours and 3 days after the plants were placed in the space. The reduction in the concentration of Benzene, Toluene, Etylbenzene, Xylene, and Formaldehyde was significantly greater when plants were present. When plants were placed near a window, the reduction of concentration was greater. The more plants were used, the more a reduction of indoor air contaminants occurred. The effect of reducing the concentration of air contaminants increased when the amount of plants increased, and when the plants were placed in sunny area. The concentration of Toluene was reduced by 45.6 microg/m(3) when 10% of the model space was occupied by Aglaonema brevispathum.

  14. Progress on Space Borne Laser Risk Reduction at Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Heaps, William S.; Novo-Gradac, Anne-Marie

    2004-01-01

    At the direction of NASA Headquarters NASA Goddard Space Flight Center (GSFC) and NASA Langley Research Center (LaRC) undertook in 2002 a program in fundamental research on laser manufacturing technologies aimed at improving the performance and lifetime of lasers sent into space for remote sensing applications. The work at GSFC has concentrated on three areas: 1) development of high power 1 micron lasers, 2) lifetime and reliability testing for 808 nm pump diodes, and 3) efficient conversion of 1 micron radiation to wavelengths needed for various remote sensing tasks. After almost 2 years of development interesting results in all three areas are beginning to emerge. Some of these results will be described along with discussion of future directions.

  15. Track Spacing for An Archimedes Spiral Search by a Maritime Patrol Aircraft (MPA) in Anti-Submarine Warfare (ASW) Operations

    DTIC Science & Technology

    2007-12-01

    search in a datum search problem was studied. To find a recommended track spacing, three analytical approaches were explored. Each of three analytical...approaches has its own strengths and weaknesses. This analysis combined three analytical functions into a single parameterized expression. To find the

  16. Enhanced Airport Capacity Through Safe, Dynamic Reductions in Aircraft Separation: NASA's Aircraft VOrtex Spacing System (AVOSS)

    NASA Technical Reports Server (NTRS)

    OConnor, Cornelius J.; Rutishauser, David K.

    2001-01-01

    An aspect of airport terminal operations that holds potential for efficiency improvements is the separation criteria applied to aircraft for wake vortex avoidance. These criteria evolved to represent safe spacing under weather conditions conducive to the longest wake hazards, and are consequently overly conservative during a significant portion of operations. Under many ambient conditions, such as moderate crosswinds or turbulence, wake hazard durations are substantially reduced. To realize this reduction NASA has developed a proof-of-concept Aircraft Vortex Spacing System (AVOSS). Successfully operated in a real-time field demonstration during July 2000 at the Dallas Ft. Worth International Airport, AVOSS is a novel integration of weather sensors, wake sensors, and analytical wake prediction algorithms. Gains in airport throughput using AVOSS spacing as compared to the current criteria averaged 6%, with peak values approaching the theoretical maximum of 16%. The average throughput gain translates to 15-40% reductions in delay when applied to realistic capacity ratios at major airports.

  17. Min-Max Spaces and Complexity Reduction in Min-Max Expansions

    SciTech Connect

    Gaubert, Stephane; McEneaney, William M.

    2012-06-15

    Idempotent methods have been found to be extremely helpful in the numerical solution of certain classes of nonlinear control problems. In those methods, one uses the fact that the value function lies in the space of semiconvex functions (in the case of maximizing controllers), and approximates this value using a truncated max-plus basis expansion. In some classes, the value function is actually convex, and then one specifically approximates with suprema (i.e., max-plus sums) of affine functions. Note that the space of convex functions is a max-plus linear space, or moduloid. In extending those concepts to game problems, one finds a different function space, and different algebra, to be appropriate. Here we consider functions which may be represented using infima (i.e., min-max sums) of max-plus affine functions. It is natural to refer to the class of functions so represented as the min-max linear space (or moduloid) of max-plus hypo-convex functions. We examine this space, the associated notion of duality and min-max basis expansions. In using these methods for solution of control problems, and now games, a critical step is complexity-reduction. In particular, one needs to find reduced-complexity expansions which approximate the function as well as possible. We obtain a solution to this complexity-reduction problem in the case of min-max expansions.

  18. The Antarctic Search for Meteorites: The Future of Space, on Earth Today - EVA Knowledge Capture Outbrief

    NASA Technical Reports Server (NTRS)

    Love, Stan

    2013-01-01

    NASA astronaut Stan Love shared his experiences with the Antarctic Search for Meteorites (ANSMET), an annual expedition to the southern continent to collect valuable samples for research in planetary science. ANSMET teams operate from isolated, remote field camps on the polar plateau, where windchill factors often reach -40 F. Several astronaut participants have noted ANSMET's similarity to a space mission. Some of the operational concepts, tools, and equipment employed by ANSMET teams may offer valuable insights to designers of future planetary surface exploration hardware.

  19. Concept annotation and search space decrement of digital photos using optical context information

    NASA Astrophysics Data System (ADS)

    Sinha, Pinaki; Jain, Ramesh

    2008-01-01

    A modern digital camera is not just a single sensor capturing light. It is an ensemble of different sensors which capture independent contextual information about the photo shooting event. This is stored as metadata in the image. In this paper, we demonstrate how the optical metadata (data related to the optics of the camera) can be retrieved, interpreted and used along with content information for organizing and indexing digital photos. Our model is based on the physics of vision and operation of a camera. We use our algorithm on images from personal photo albums. Our results show that the optical metadata improves annotation performance and decreases the search space for retrieval.

  20. Calculation reduction method for color digital holography and computer-generated hologram using color space conversion

    NASA Astrophysics Data System (ADS)

    Shimobaba, Tomoyoshi; Nagahama, Yuki; Kakue, Takashi; Takada, Naoki; Okada, Naohisa; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Ito, Tomoyoshi

    2014-02-01

    A calculation reduction method for color digital holography (DH) and computer-generated holograms (CGHs) using color space conversion is reported. Color DH and color CGHs are generally calculated on RGB space. We calculate color DH and CGHs in other color spaces for accelerating the calculation (e.g., YCbCr color space). In YCbCr color space, a RGB image or RGB hologram is converted to the luminance component (Y), blue-difference chroma (Cb), and red-difference chroma (Cr) components. In terms of the human eye, although the negligible difference of the luminance component is well recognized, the difference of the other components is not. In this method, the luminance component is normal sampled and the chroma components are down-sampled. The down-sampling allows us to accelerate the calculation of the color DH and CGHs. We compute diffraction calculations from the components, and then we convert the diffracted results in YCbCr color space to RGB color space. The proposed method, which is possible to accelerate the calculations up to a factor of 3 in theory, accelerates the calculation over two times faster than the ones in RGB color space.

  1. Searching for biological rhythms: peak detection in the periodogram of unequally spaced data.

    PubMed

    Van Dongen, H P; Olofsen, E; VanHartevelt, J H; Kruyt, E W

    1999-12-01

    The classical power spectrum, computed in the frequency domain, outranks traditionally used periodograms derived in the time domain (such as the chi2 periodogram) regarding the search for biological rhythms. Unfortunately, classical power spectral analysis is not possible with unequally spaced data (e.g., time series with missing data). The Lomb-Scargle periodogram fixes this shortcoming. However, peak detection in the Lomb-Scargle periodogram of unequally spaced data requires some careful consideration. To guide researchers in the proper evaluation of detected peaks, therefore, a novel procedure and a computer program have recently become available. It is recommended that the Lomb-Scargle periodogram be the default method of periodogram analysis in future biomedical applications of rhythm investigation.

  2. Reaction engineering for materials processing in space: Reduction of ilmenite by hydrogen and carbon monoxide

    NASA Technical Reports Server (NTRS)

    Zhao, Y.; Shadman, F.

    1991-01-01

    Oxygen is a consumable material which needs to be produced continuously in most space missions. Its use for propulsion as well as life support makes oxygen one of the largest volume chemicals to be produced in space. Production of oxygen from lunar materials is of particular interest and is very attractive possibility. The kinetics and mechanism of reduction of ilmenite by carbon monoxide and hydrogen at 800 to 1100 C were investigated. The temporal profiles of conversion for carbon monoxide have a sigmoidal shape and indicate the presence of three different stages (induction, acceleration, and deceleration) during the reduction reaction. The apparent activation energy decreases from 18 kcal/mole at 10 percent conversion to 10 kcal/mole at 50 percent conversion. The reaction is first order with respect to carbon monoxide under the experimental conditions studied. Both SEM and EDX analysis show that the diffusion of Fe product away from the reaction front and through the TiO2 phase, followed by the nucleation and growth of a separate Fe phase are important steps affecting the process kinetics. The results from hydrogen reduction show that the mechanism of ilmenite reduction by hydrogen is similar to that by carbon monoxide. However, the titanium dioxide can be further reduced by hydrogen at 800 to 1000 C. The detailed comparison and theoretical modeling of both reduction processes is presented.

  3. Program documentation for the space environment test division post-test data reduction program (GNFLEX)

    NASA Technical Reports Server (NTRS)

    Jones, L. D.

    1979-01-01

    The Space Environment Test Division Post-Test Data Reduction Program processes data from test history tapes generated on the Flexible Data System in the Space Environment Simulation Laboratory at the National Aeronautics and Space Administration/Lyndon B. Johnson Space Center. The program reads the tape's data base records to retrieve the item directory conversion file, the item capture file and the process link file to determine the active parameters. The desired parameter names are read in by lead cards after which the periodic data records are read to determine parameter data level changes. The data is considered to be compressed rather than full sample rate. Tabulations and/or a tape for generating plots may be output.

  4. Reduction of the spermatogonial population in rat testes flown on Space Lab-3

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Stevenson, J.; Corbett, R.; Sapp, W.; Williams, C.

    1985-01-01

    Quantization of the testicular spermatogonial population reduction in six rats is performed 12 hours after their return from seven days aboard Space Lab-3. The observed 7.1 percent organ weight loss, and 7.5 percent stage six spermatogonial cell population reduction in comparison with control rats correlate very well. Accurate dosimetry was not conducted on board, but radiation can not be considered the primary cause of the observed change. The decrease in protein kinase in the heart of these rats indicates that stress from adapting to weightlessness, the final jet flight, or other sources, is an important factor.

  5. Searching for Faint Companions to Nearby Stars with the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Schroeder, Daniel J.; Golimowski, David A.

    1996-01-01

    A search for faint companions (FC's) to selected stars within 5 pc of the Sun using the Hubble Space Telescope's Planetary Camera (PC) has been initiated. To assess the PC's ability to detect FCs, we have constructed both model and laboratory-simulated images and compared them to actual PC images. We find that the PC's point-spread function (PSF) is 3-4 times brighter over the angular range 2-5 sec than the PSF expected for a perfect optical system. Azimuthal variations of the PC's PSF are 10-20 times larger than expected for a perfect PSF. These variations suggest that light is scattered nonuniformly from the surface of the detector. Because the anomalies in the PC's PSF cannot be precisely simulated, subtracting a reference PSF from the PC image is problematic. We have developed a computer algorithm that identifies local brightness anomalies within the PSF as potential FCs. We find that this search algorithm will successfully locate FCs anywhere within the circumstellar field provided that the average pixel signal from the FC is at least 10 sigma above the local background. This detection limit suggests that a comprehensive search for extrasolar Jovian planets with the PC is impractical. However, the PC is useful for detecting other types of substellar objects. With a stellar signal of 10(exp 9) e(-), for example, we may detect brown dwarfs as faint as M(sub I) = 16.7 separated by 1 sec from alpha Cen A.

  6. The universe formation by space reduction cascades with random initial parameters

    NASA Astrophysics Data System (ADS)

    Rubin, Sergei; Zinger, Alexey

    2012-09-01

    In this paper we discuss the creation of our universe using the idea of extra dimensions. The initial, multidimensional Lagrangian contains only metric tensor. We have found many sets of the numerical values of the Lagrangian parameters corresponding to the observed low-energy physics of our Universe. Different initial parameters can lead to the same values of fundamental constants by the appropriate choice of a dimensional reduction cascade. This result diminishes the significance of the search for the `unique' initial Lagrangian. We also have obtained a large number of low-energy vacua, which is known as `landscape' in the string theory.

  7. Exploration an the Search for Origins: A Vision for Ultraviolet-Optical-Infrared Space Astronomy

    NASA Technical Reports Server (NTRS)

    Dressler, Alan (Editor); Brown, Robert A.; Davidsen, Arthur F.; Ellis, Richard S.; Freedman, Wendy L.; Green, Richard F.; Hauser, Michael G.; Kirshner, Robert P.; Kulkarni, Shrinivas; Lilly, Simon J.; Margon, Bruce H.; Porco, Carolyn C.; Richstone, Douglas O.; Stockman, H. S.; Thronson, Harley A., Jr.; Tonry, John L.; Truran, James; Weiler, Edward J.

    1996-01-01

    Public support and enthusiasm for astronomy have been strong in the final decades of the twentieth century. Nowhere is this better demonstrated than with the Hubble Space Telescope (HCT), a grand endeavor, which is enabling astronomers to make giant strides in understanding our universe, our place in it, and our relation to it. The NASAs first infrared observatory, the Space Infrared Telescope Facility (SIRTF), promises to take the crucial next steps towards understanding the formation of stars and galaxies. Toward their completion, the HST and Beyond Committee identifies major goals, whose accomplishment will justify a commitment well into the next century: (1) the detailed study of the birth and evolution of normal galaxies such as the Milky Way; (2) the detection of Earth-like planets around other stars and the search for evidence of life on them; (3) NASA should develop a space observatory of aperture 4m or larger, optimized for imaging and spectroscopy over the wavelength range 1-5 microns; and (4) NASA should develop the capability for space interferometry.

  8. Never Use the Complete Search Space: a Concept to Enhance the Optimization Procedure for Monitoring Networks

    NASA Astrophysics Data System (ADS)

    Bode, F.; Reuschen, S.; Nowak, W.

    2015-12-01

    Drinking-water well catchments include many potential sources of contaminations like gas stations or agriculture. Finding optimal positions of early-warning monitoring wells is challenging because there are various parameters (and their uncertainties) that influence the reliability and optimality of any suggested monitoring location or monitoring network.The overall goal of this project is to develop and establish a concept to assess, design and optimize early-warning systems within well catchments. Such optimal monitoring networks need to optimize three competing objectives: a high detection probability, which can be reached by maximizing the "field of vision" of the monitoring network, a long early-warning time such that there is enough time left to install counter measures after first detection, and the overall operating costs of the monitoring network, which should ideally be reduced to a minimum. The method is based on numerical simulation of flow and transport in heterogeneous porous media coupled with geostatistics and Monte-Carlo, scenario analyses for real data, respectively, wrapped up within the framework of formal multi-objective optimization using a genetic algorithm.In order to speed up the optimization process and to better explore the Pareto-front, we developed a concept that forces the algorithm to search only in regions of the search space where promising solutions can be expected. We are going to show how to define these regions beforehand, using knowledge of the optimization problem, but also how to define them independently of problem attributes. With that, our method can be used with and/or without detailed knowledge of the objective functions.In summary, our study helps to improve optimization results in less optimization time by meaningful restrictions of the search space. These restrictions can be done independently of the optimization problem, but also in a problem-specific manner.

  9. rasbhari: Optimizing Spaced Seeds for Database Searching, Read Mapping and Alignment-Free Sequence Comparison

    PubMed Central

    Hahn, Lars; Leimeister, Chris-André; Morgenstern, Burkhard

    2016-01-01

    Many algorithms for sequence analysis rely on word matching or word statistics. Often, these approaches can be improved if binary patterns representing match and don’t-care positions are used as a filter, such that only those positions of words are considered that correspond to the match positions of the patterns. The performance of these approaches, however, depends on the underlying patterns. Herein, we show that the overlap complexity of a pattern set that was introduced by Ilie and Ilie is closely related to the variance of the number of matches between two evolutionarily related sequences with respect to this pattern set. We propose a modified hill-climbing algorithm to optimize pattern sets for database searching, read mapping and alignment-free sequence comparison of nucleic-acid sequences; our implementation of this algorithm is called rasbhari. Depending on the application at hand, rasbhari can either minimize the overlap complexity of pattern sets, maximize their sensitivity in database searching or minimize the variance of the number of pattern-based matches in alignment-free sequence comparison. We show that, for database searching, rasbhari generates pattern sets with slightly higher sensitivity than existing approaches. In our Spaced Words approach to alignment-free sequence comparison, pattern sets calculated with rasbhari led to more accurate estimates of phylogenetic distances than the randomly generated pattern sets that we previously used. Finally, we used rasbhari to generate patterns for short read classification with CLARK-S. Here too, the sensitivity of the results could be improved, compared to the default patterns of the program. We integrated rasbhari into Spaced Words; the source code of rasbhari is freely available at http://rasbhari.gobics.de/ PMID:27760124

  10. A mechanism of basal spacing reduction in sodium smectitic clay materials in contact with DNAPL wastes.

    PubMed

    Ayral-Cinar, Derya; Otero-Diaz, Margarita; Demond, Avery H

    2016-09-01

    There has been concern regarding the possible attack of clays in aquitards, slurry walls and landfill liners by dense nonaqueous phase liquid (DNAPL) wastes, resulting in cracking. Despite the fact that a reduction in basal spacing in sodium smectitic clay materials has been linked to cracking, no plausible mechanism by which this reduction occurs in contact with waste DNAPLs has been formulated. To elucidate a mechanism, screening studies were conducted that showed that the combination of an anionic surfactant (AOT), a nonionic surfactant (TritonX-100) and a chlorinated solvent, tetrachloroethylene (PCE), could replicate the basal spacing reduction and cracking behavior of water-saturated bentonite caused by two waste DNAPLs obtained from the field. FTIR measurements of this system showed a displacement of the HOH bending band of water symptomatic of desiccation. Sorption measurements showed that the uptake of AOT by bentonite increased eight fold in the presence of TritonX-100 and PCE. The evidence presented here supports a mechanism of syneresis, involving the extraction of water from the interlayer space of the clay through the synergistic sorption of a nonionic and anionic surfactant mixture. It is speculated that the solvation of water in reverse micellar aggregates is the process driving the syneresis.

  11. Space shuttle solid rocket booster main parachute damage reduction team report

    NASA Technical Reports Server (NTRS)

    Watts, G.

    1993-01-01

    This report gives the findings of the space shuttle solid rocket booster main parachute damage reduction team. The purpose of the team was to investigate the causes of main parachute deployment damage and to recommend methods to eliminate or substantially reduce the damage. The team concluded that the two primary causes of significant damage during deployment are vent entanglement and contact of the parachutes with the main parachute support structure. As an inexpensive but effective step towards damage reduction, the team recommends modification of the parachute packing procedure to eliminate vent entanglement. As the most effective design change, the team recommends a pilot chute-deployed soft-pack system. Alternative concepts are also recommended that provide a major reduction in damage at a total cost lower than the pilot chute-deployed soft pack.

  12. Neutron Monitor Observations and Space Weather, 1. Automatically Search of Great Solar Energetic Particle Event Beginning.

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.; Pustil'Nik, L. A.; Sternlieb, A.; Zukerman, I. G.

    It is well known that in periods of great SEP fluxes of energetic particles can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead: according to NOAA Space Weather Scales are danger- ous Solar Radiation Storms S5-extreme (flux level of particles with energy > 10 MeV more than 10^5), S4-severe (flux more than 10^4) and S3-strong (flux more than 10^3). In these periods is necessary to switch off some part of electronics for few hours to protect computer memories. These periods are also dangerous for astronauts on space- ships, and passengers and crew in commercial jets (especially during S5 storms). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (few GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coeffi- cient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into so- lar wind) than main part of smaller energy particles caused dangerous situation for electronics (about 30-60 minutes later). We describe here principles and experience of automatically working of program "FEP-Search". The positive result which shows the exact beginning of FEP event on the Emilio Segre' Observatory (2025 m above sea level, Rc=10.8 GV), is determined now automatically by simultaneously increas- ing on 2.5 St. Dev. in two sections of neutron supermonitor. The next 1-min data the program "FEP-Search" uses for checking that the observed increase reflects the begin- ning of real great FEP or not. If yes, automatically starts to work on line the programs "FEP-Research".

  13. Catalytic Tar Reduction for Assistance in Thermal Conversion of Space Waste for Energy Production

    NASA Technical Reports Server (NTRS)

    Caraccio, Anne Joan; Devor, Robert William; Hintze, Paul E.; Muscatello, Anthony C.; Nur, Mononita

    2014-01-01

    The Trash to Gas (TtG) project investigates technologies for converting waste generated during spaceflight into various resources. One of these technologies was gasification, which employed a downdraft reactor designed and manufactured at NASA's Kennedy Space Center (KSC) for the conversion of simulated space trash to carbon dioxide. The carbon dioxide would then be converted to methane for propulsion and water for life support systems. A minor byproduct of gasification includes large hydrocarbons, also known as tars. Tars are unwanted byproducts that add contamination to the product stream, clog the reactor and cause complications in analysis instrumentation. The objective of this research was to perform reduction studies of a mock tar using select catalysts and choose the most effective for primary treatment within the KSC downdraft gasification reactor. Because the KSC reactor is operated at temperatures below typical gasification reactors, this study evaluates catalyst performance below recommended catalytic operating temperatures. The tar reduction experimentation was observed by passing a model tar vapor stream over the catalysts at similar conditions to that of the KSC reactor. Reduction in tar was determined using gas chromatography. Tar reduction efficiency and catalyst performances were evaluated at different temperatures.

  14. A fuzzy discrete harmony search algorithm applied to annual cost reduction in radial distribution systems

    NASA Astrophysics Data System (ADS)

    Ameli, Kazem; Alfi, Alireza; Aghaebrahimi, Mohammadreza

    2016-09-01

    Similarly to other optimization algorithms, harmony search (HS) is quite sensitive to the tuning parameters. Several variants of the HS algorithm have been developed to decrease the parameter-dependency character of HS. This article proposes a novel version of the discrete harmony search (DHS) algorithm, namely fuzzy discrete harmony search (FDHS), for optimizing capacitor placement in distribution systems. In the FDHS, a fuzzy system is employed to dynamically adjust two parameter values, i.e. harmony memory considering rate and pitch adjusting rate, with respect to normalized mean fitness of the harmony memory. The key aspect of FDHS is that it needs substantially fewer iterations to reach convergence in comparison with classical discrete harmony search (CDHS). To the authors' knowledge, this is the first application of DHS to specify appropriate capacitor locations and their best amounts in the distribution systems. Simulations are provided for 10-, 34-, 85- and 141-bus distribution systems using CDHS and FDHS. The results show the effectiveness of FDHS over previous related studies.

  15. Charting epilepsy by searching for intelligence in network space with the help of evolving autonomous agents.

    PubMed

    Ohayon, Elan L; Kalitzin, Stiliyan; Suffczynski, Piotr; Jin, Frank Y; Tsang, Paul W; Borrett, Donald S; Burnham, W McIntyre; Kwan, Hon C

    2004-01-01

    The problem of demarcating neural network space is formidable. A simple fully connected recurrent network of five units (binary activations, synaptic weight resolution of 10) has 3.2 *10(26) possible initial states. The problem increases drastically with scaling. Here we consider three complementary approaches to help direct the exploration to distinguish epileptic from healthy networks. [1] First, we perform a gross mapping of the space of five-unit continuous recurrent networks using randomized weights and initial activations. The majority of weight patterns (>70%) were found to result in neural assemblies exhibiting periodic limit-cycle oscillatory behavior. [2] Next we examine the activation space of non-periodic networks demonstrating that the emergence of paroxysmal activity does not require changes in connectivity. [3] The next challenge is to focus the search of network space to identify networks with more complex dynamics. Here we rely on a major available indicator critical to clinical assessment but largely ignored by epilepsy modelers, namely: behavioral states. To this end, we connected the above network layout to an external robot in which interactive states were evolved. The first random generation showed a distribution in line with approach [1]. That is, the predominate phenotypes were fixed-point or oscillatory with seizure-like motor output. As evolution progressed the profile changed markedly. Within 20 generations the entire population was able to navigate a simple environment with all individuals exhibiting multiply-stable behaviors with no cases of default locked limit-cycle oscillatory motor behavior. The resultant population may thus afford us a view of the architectural principles demarcating healthy biological networks from the pathological. The approach has an advantage over other epilepsy modeling techniques in providing a way to clarify whether observed dynamics or suggested therapies are pointing to computational viability or dead

  16. (abstract) Spacecraft Doppler Tracking with the Deep Space Network in the Search for Gravitational Waves

    NASA Technical Reports Server (NTRS)

    Asmar, Sami; Renzetti, Nicholas

    1994-01-01

    The Deep Space Network generates accurate radio science data observables for investigators who use radio links between spacecraft and the Earth to examine small changes in the phase and/or amplitude of the signal to study a wide variety of structures and phenomena in space. Several such studies are directed at aspects of the theory of general relativity such as gravitational redshift and gravitational waves. A gravitational wave is a propagating, polarized gravitational field, a ripple in the curvature of space-time. In Einstein's theory of general relativity, the waves are propagating solutions of the Einstein field equations. Their amplitudes are dimensionless strain amplitudes that change the fractional difference in distance between test masses and the rates at which separated clocks keep time. Predicted by all relativistic theories of gravity, they are extremely weak (the ratio of gravitational forces to electrical forces is about 10(sup -40)) and are generated at detectable levels only by astrophysical sources - very massive sources under violent dynamical conditions. The waves have never been detected but searches in the low-frequency band using Doppler tracking of many spacecraft have been conducted and others are being planned. Upper limits have been placed on the gravitational wave strength with the best sensitivities to date are for periodic waves being 7 x 10(sup -15).

  17. Far-space neglect in conjunction but not feature search following transcranial magnetic stimulation over right posterior parietal cortex.

    PubMed

    Mahayana, Indra T; Liu, Chia-Lun; Chang, Chi Fu; Hung, Daisy L; Tzeng, Ovid J L; Juan, Chi-Hung; Muggleton, Neil G

    2014-02-01

    Near- and far-space coding in the human brain is a dynamic process. Areas in dorsal, as well as ventral visual association cortex, including right posterior parietal cortex (rPPC), right frontal eye field (rFEF), and right ventral occipital cortex (rVO), have been shown to be important in visuospatial processing, but the involvement of these areas when the information is in near or far space remains unclear. There is a need for investigations of these representations to help explain the pathophysiology of hemispatial neglect, and the role of near and far space is crucial to this. We used a conjunction visual search task using an elliptical array to investigate the effects of transcranial magnetic stimulation delivered over rFEF, rPPC, and rVO on the processing of targets in near and far space and at a range of horizontal eccentricities. As in previous studies, we found that rVO was involved in far-space search, and rFEF was involved regardless of the distance to the array. It was found that rPPC was involved in search only in far space, with a neglect-like effect when the target was located in the most eccentric locations. No effects were seen for any site for a feature search task. As the search arrays had higher predictability with respect to target location than is often the case, these data may form a basis for clarifying both the role of PPC in visual search and its contribution to neglect, as well as the importance of near and far space in these.

  18. Lagrangian reduction of search-range for large-scale unit commitment

    SciTech Connect

    Nieva, R.; India, A.; Guillen, I.

    1987-05-01

    This paper is concerned with the thermal unit commitment problem for Large-Scale Power Systems. A new approach capable of producing low-cost solutions in relatively short execution times is presented. The proposed technique applies Dynamic Programming in successive approximations. A reduced search-range is determined for each successive iteration by means of a Lagrangian technique. Results are given and discussed for very large and complex unit commitment problems.

  19. Development and evaluation of a biomedical search engine using a predicate-based vector space model.

    PubMed

    Kwak, Myungjae; Leroy, Gondy; Martinez, Jesse D; Harwell, Jeffrey

    2013-10-01

    Although biomedical information available in articles and patents is increasing exponentially, we continue to rely on the same information retrieval methods and use very few keywords to search millions of documents. We are developing a fundamentally different approach for finding much more precise and complete information with a single query using predicates instead of keywords for both query and document representation. Predicates are triples that are more complex datastructures than keywords and contain more structured information. To make optimal use of them, we developed a new predicate-based vector space model and query-document similarity function with adjusted tf-idf and boost function. Using a test bed of 107,367 PubMed abstracts, we evaluated the first essential function: retrieving information. Cancer researchers provided 20 realistic queries, for which the top 15 abstracts were retrieved using a predicate-based (new) and keyword-based (baseline) approach. Each abstract was evaluated, double-blind, by cancer researchers on a 0-5 point scale to calculate precision (0 versus higher) and relevance (0-5 score). Precision was significantly higher (p<.001) for the predicate-based (80%) than for the keyword-based (71%) approach. Relevance was almost doubled with the predicate-based approach-2.1 versus 1.6 without rank order adjustment (p<.001) and 1.34 versus 0.98 with rank order adjustment (p<.001) for predicate--versus keyword-based approach respectively. Predicates can support more precise searching than keywords, laying the foundation for rich and sophisticated information search.

  20. A search for experiments to exploit the space shuttle environment, volume 1

    NASA Technical Reports Server (NTRS)

    Fenn, J. B.

    1979-01-01

    A search for worthwhile experiments in pure and applied physics and chemistry which might take advantage of conditions achievable aboard the space shuttle is documented. Of particular interest were the very large pumping speeds at high or ultra high vacuum, the highly nonequilibrium composition of the ambient atmosphere, and the relative absence of gravitational effects. Ideas and suggestions were solicated in the course of visits to 31 research establishments in Western Europe, India, and Japan; conversations with over 90 scientists; and presentations at 3 international meetings. Intriguing possibilities emerged in the following arenas: (1) spectroscopy of the transition state in chemical reactions; (2) flame structure and analysis; (3) solid propellant combustion; (4) analysis of atmospheric composition; (5) turbulence effects on aerosol coagulation.

  1. Three Dimensional Defect Reconstruction Using State Space Search and Woodbury's Substructure Method

    NASA Astrophysics Data System (ADS)

    Liu, X.; Deng, Y.; Li, Y.; Udpa, L.; Udpa, S. S.

    2010-02-01

    This paper introduces a model-based approach to reconstruct the three-dimensional defect profiles using eddy-current heat exchanger tube inspection signals. The method uses a Woodbury's substructure finite element forward model to simulate the underlying physics, a state space defect representation, and a tree search algorithm to solve the inverse problem. The advantage of the substructure method is that it divides the whole solution domain into two substructures and only the region of interest (ROI) with dramatic material changes will be updated in each iterative step. Since the number of elements inside the ROI is very small compared with the number of elements in the entire mesh, the computational effort needed in both LU factorization and coefficient matrix assembly is reduced. Therefore, the execution time is reduced significantly making the inversion very efficient. The initial inversion results are presented to confirm the validity of the approach.

  2. A trust-based sensor allocation algorithm in cooperative space search problems

    NASA Astrophysics Data System (ADS)

    Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik

    2011-06-01

    Sensor allocation is an important and challenging problem within the field of multi-agent systems. The sensor allocation problem involves deciding how to assign a number of targets or cells to a set of agents according to some allocation protocol. Generally, in order to make efficient allocations, we need to design mechanisms that consider both the task performers' costs for the service and the associated probability of success (POS). In our problem, the costs are the used sensor resource, and the POS is the target tracking performance. Usually, POS may be perceived differently by different agents because they typically have different standards or means of evaluating the performance of their counterparts (other sensors in the search and tracking problem). Given this, we turn to the notion of trust to capture such subjective perceptions. In our approach, we develop a trust model to construct a novel mechanism that motivates sensor agents to limit their greediness or selfishness. Then we model the sensor allocation optimization problem with trust-in-loop negotiation game and solve it using a sub-game perfect equilibrium. Numerical simulations are performed to demonstrate the trust-based sensor allocation algorithm in cooperative space situation awareness (SSA) search problems.

  3. Medical Response, Search and Recovery during the Space Shuttle Columbia Accident Investigation

    NASA Technical Reports Server (NTRS)

    Stepaniak, Philip C.

    2010-01-01

    On February 1, 2003, the Space Shuttle Columbia broke apart during atmospheric re-entry on mission STS-107. After an event such as this, with high visibility and international interest, the operational challenge of recovering the crewmembers could not be underestimated. The Space Shuttle Program is organized to respond to a vehicle mishap using the resources of the Mishap Investigation Team (MIT). On the afternoon of Feb. 1, 2003, the MIT deployed to Barksdale Air Force Base (AFB), Louisiana. This location became the investigative center and interim storage location for crewmembers received from the Lufkin, Texas Disaster Field Office (DFO). The Lufkin DFO served as the primary area for all operations, including staging assets and deploying field teams for search, recovery and security of crewmember remains. More than 2,000 people from numerous organizations were involved with the recovery of the crew. All seven crewmembers of STS-107 were recovered and ceremonial last rights were administered. Astronaut and military personnel escorted the crew with honor to the MIT at Barksdale AFB, Louisiana. At Barksdale AFB a temporary morgue was established in an aircraft hangar and operated for approximately two weeks during which time coordination with the DFO field recovery teams, Armed Forces Institute of Pathology (AFIP) medical personnel, and the crew surgeons was on going. Families of crewmembers and NASA management were notified daily of the current findings. Working under the leadership of the MIT Lead, the medical team developed and executed a short-term plan to identify and relocate the crew with a military honor guard and protocol to the medical examiner at the Armed Forces Port Mortuary, Dover AFB, Delaware. After operations at Barksdale AFB were concluded the medical team transitioned back to Houston and a long-term plan was developed and implemented which involved the Air Force Mortuary Affairs at Randolph AFB, Texas. This plan was coordinated with search teams

  4. Mitigating local minima in full-waveform inversion by expanding the search space

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Tristan; Herrmann, Felix J.

    2013-10-01

    Wave equation based inversions, such as full-waveform inversion and reverse-time migration, are challenging because of their computational costs, memory requirements and reliance on accurate initial models. To confront these issues, we propose a novel formulation of wave equation based inversion based on a penalty method. In this formulation, the objective function consists of a data-misfit term and a penalty term, which measures how accurately the wavefields satisfy the wave equation. This new approach is a major departure from current formulations where forward and adjoint wavefields, which both satisfy the wave equation, are correlated to compute updates for the unknown model parameters. Instead, we carry out the inversions over two alternating steps during which we first estimate the wavefield everywhere, given the current model parameters, source and observed data, followed by a second step during which we update the model parameters, given the estimate for the wavefield everywhere and the source. Because the inversion involves both the synthetic wavefields and the medium parameters, its search space is enlarged so that it suffers less from local minima. Compared to other formulations that extend the search space of wave equation based inversion, our method differs in several aspects, namely (i) it avoids storage and updates of the synthetic wavefields because we calculate these explicitly by finding solutions that obey the wave equation and fit the observed data and (ii) no adjoint wavefields are required to update the model, instead our updates are calculated from these solutions directly, which leads to significant computational savings. We demonstrate the validity of our approach by carefully selected examples and discuss possible extensions and future research.

  5. Risk reduction activities for an F-1-based advanced booster for NASA's Space Launch System

    NASA Astrophysics Data System (ADS)

    Crocker, A. M.; Doering, K. B.; Cook, S. A.; Meadows, R. G.; Lariviere, B. W.; Bachtel, F. D.

    For NASA's Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) procurement, Dynetics, Inc. and Pratt & Whitney Rocketdyne (PWR) formed a team to offer a wide-ranging set of risk reduction activities and full-scale, system-level demonstrations that support NASA's goal of enabling competition on an affordable booster that meets the evolved capabilities of the SLS. During the ABEDRR effort, the Dynetics Team will apply state-of-the-art manufacturing and processing techniques to the heritage F-1, resulting in a low recurring cost engine while retaining the benefits of Apollo-era experience. ABEDRR will use NASA test facilities to perform full-scale F-1 gas generator and powerpack hot-fire test campaigns for engine risk reduction. Dynetics will also fabricate and test a tank assembly to verify the structural design. The Dynetics Team is partnered with NASA through Space Act Agreements (SAAs) to maximize the expertise and capabilities applied to ABEDRR.

  6. Importance of interatomic spacing in catalytic reduction of oxygen in phosphoric acid

    NASA Technical Reports Server (NTRS)

    Jalan, V.; Taylor, E. J.

    1983-01-01

    A correlation between the nearest-neighbor distance and the oxygen reduction activity of various platinum alloys is reported. It is proposed that the distance between nearest-neighbor Pt atoms on the surface of a supported catalyst is not ideal for dual site absorption of O2 or 'HO2' and that the introduction of foreign atoms which reduce the Pt nearest-neighbor spacing would result in higher oxygen reduction activity. This may allow the critical 0-0 bond interatomic distance and hence the optimum Pt-Pt separation for bond rupture to be determined from quantum chemical calculations. A composite analysis shows that the data on supported Pt alloys are consistent with Appleby's (1970) data on bulk metals with respect to specific activity, activation energy, preexponential factor, and percent d-band character.

  7. GeneLab Phase 2: Integrated Search Data Federation of Space Biology Experimental Data

    NASA Technical Reports Server (NTRS)

    Tran, P. B.; Berrios, D. C.; Gurram, M. M.; Hashim, J. C. M.; Raghunandan, S.; Lin, S. Y.; Le, T. Q.; Heher, D. M.; Thai, H. T.; Welch, J. D.; Caldwell, S. M.; Stotzky, O. G.; Skidmore, M. G.

    2016-01-01

    The GeneLab project is a science initiative to maximize the scientific return of omics data collected from spaceflight and from ground simulations of microgravity and radiation experiments, supported by a data system for a public bioinformatics repository and collaborative analysis tools for these data. The mission of GeneLab is to maximize the utilization of the valuable biological research resources aboard the ISS by collecting genomic, transcriptomic, proteomic and metabolomic (so-called omics) data to enable the exploration of the molecular network responses of terrestrial biology to space environments using a systems biology approach. All GeneLab data are made available to a worldwide network of researchers through its open-access data system. GeneLab is currently being developed by NASA to support Open Science biomedical research in order to enable the human exploration of space and improve life on earth. Open access to Phase 1 of the GeneLab Data Systems (GLDS) was implemented in April 2015. Download volumes have grown steadily, mirroring the growth in curated space biology research data sets (61 as of June 2016), now exceeding 10 TB/month, with over 10,000 file downloads since the start of Phase 1. For the period April 2015 to May 2016, most frequently downloaded were data from studies of Mus musculus (39) followed closely by Arabidopsis thaliana (30), with the remaining downloads roughly equally split across 12 other organisms (each 10 of total downloads). GLDS Phase 2 is focusing on interoperability, supporting data federation, including integrated search capabilities, of GLDS-housed data sets with external data sources, such as gene expression data from NIHNCBIs Gene Expression Omnibus (GEO), proteomic data from EBIs PRIDE system, and metagenomic data from Argonne National Laboratory's MG-RAST. GEO and MG-RAST employ specifications for investigation metadata that are different from those used by the GLDS and PRIDE (e.g., ISA-Tab). The GLDS Phase 2 system

  8. ODF Maxima Extraction in Spherical Harmonic Representation via Analytical Search Space Reduction

    DTIC Science & Technology

    2010-05-01

    scheme to approximate the signal, and then by analytically computing the Funk- Radon transform, [2], following the method introduced in [3]–[5] for... 222 (2008) 12. Tournier, J., Calamante, F., Gadian, D., Connelly, A.: Direct estimation of the fiber orientation density function from diffusion

  9. The Space Technology-7 Disturbance Reduction System Precision Control Flight Validation Experiment Control System Design

    NASA Technical Reports Server (NTRS)

    O'Donnell, James R.; Hsu, Oscar C.; Maghami, Peirman G.; Markley, F. Landis

    2006-01-01

    As originally proposed, the Space Technology-7 Disturbance Reduction System (DRS) project, managed out of the Jet Propulsion Laboratory, was designed to validate technologies required for future missions such as the Laser Interferometer Space Antenna (LISA). The two technologies to be demonstrated by DRS were Gravitational Reference Sensors (GRSs) and Colloidal MicroNewton Thrusters (CMNTs). Control algorithms being designed by the Dynamic Control System (DCS) team at the Goddard Space Flight Center would control the spacecraft so that it flew about a freely-floating GRS test mass, keeping it centered within its housing. For programmatic reasons, the GRSs were descoped from DRS. The primary goals of the new mission are to validate the performance of the CMNTs and to demonstrate precise spacecraft position control. DRS will fly as a part of the European Space Agency (ESA) LISA Pathfinder (LPF) spacecraft along with a similar ESA experiment, the LISA Technology Package (LTP). With no GRS, the DCS attitude and drag-free control systems make use of the sensor being developed by ESA as a part of the LTP. The control system is designed to maintain the spacecraft s position with respect to the test mass, to within 10 nm/the square root of Hz over the DRS science frequency band of 1 to 30 mHz.

  10. HUBBLE SPACE TELESCOPE SNAPSHOT SEARCH FOR PLANETARY NEBULAE IN GLOBULAR CLUSTERS OF THE LOCAL GROUP

    SciTech Connect

    Bond, Howard E.

    2015-04-15

    Single stars in ancient globular clusters (GCs) are believed incapable of producing planetary nebulae (PNs), because their post-asymptotic-giant-branch evolutionary timescales are slower than the dissipation timescales for PNs. Nevertheless, four PNs are known in Galactic GCs. Their existence likely requires more exotic evolutionary channels, including stellar mergers and common-envelope binary interactions. I carried out a snapshot imaging search with the Hubble Space Telescope (HST) for PNs in bright Local Group GCs outside the Milky Way. I used a filter covering the 5007 Å nebular emission line of [O iii], and another one in the nearby continuum, to image 66 GCs. Inclusion of archival HST frames brought the total number of extragalactic GCs imaged at 5007 Å to 75, whose total luminosity slightly exceeds that of the entire Galactic GC system. I found no convincing PNs in these clusters, aside from one PN in a young M31 cluster misclassified as a GC, and two PNs at such large angular separations from an M31 GC that membership is doubtful. In a ground-based spectroscopic survey of 274 old GCs in M31, Jacoby et al. found three candidate PNs. My HST images of one of them suggest that the [O iii] emission actually arises from ambient interstellar medium rather than a PN; for the other two candidates, there are broadband archival UV HST images that show bright, blue point sources that are probably the PNs. In a literature search, I also identified five further PN candidates lying near old GCs in M31, for which follow-up observations are necessary to confirm their membership. The rates of incidence of PNs are similar, and small but nonzero, throughout the GCs of the Local Group.

  11. Direct-to-digital holography reduction of reference hologram noise and fourier space smearing

    DOEpatents

    Voelkl, Edgar

    2006-06-27

    Systems and methods are described for reduction of reference hologram noise and reduction of Fourier space smearing, especially in the context of direct-to-digital holography (off-axis interferometry). A method of reducing reference hologram noise includes: recording a plurality of reference holograms; processing the plurality of reference holograms into a corresponding plurality of reference image waves; and transforming the corresponding plurality of reference image waves into a reduced noise reference image wave. A method of reducing smearing in Fourier space includes: recording a plurality of reference holograms; processing the plurality of reference holograms into a corresponding plurality of reference complex image waves; transforming the corresponding plurality of reference image waves into a reduced noise reference complex image wave; recording a hologram of an object; processing the hologram of the object into an object complex image wave; and dividing the complex image wave of the object by the reduced noise reference complex image wave to obtain a reduced smearing object complex image wave.

  12. NASA's Space Launch System Advanced Booster Engineering Demonstration and/or Risk Reduction Efforts

    NASA Technical Reports Server (NTRS)

    Crumbly, Christopher M.; Dumbacher, Daniel L.; May, Todd A.

    2012-01-01

    The National Aeronautics and Space Administration (NASA) formally initiated the Space Launch System (SLS) development in September 2011, with the approval of the program s acquisition plan, which engages the current workforce and infrastructure to deliver an initial 70 metric ton (t) SLS capability in 2017, while using planned block upgrades to evolve to a full 130 t capability after 2021. A key component of the acquisition plan is a three-phased approach for the first stage boosters. The first phase is to complete the development of the Ares and Space Shuttle heritage 5-segment solid rocket boosters (SRBs) for initial exploration missions in 2017 and 2021. The second phase in the booster acquisition plan is the Advanced Booster Risk Reduction and/or Engineering Demonstration NASA Research Announcement (NRA), which was recently awarded after a full and open competition. The NRA was released to industry on February 9, 2012, with a stated intent to reduce risks leading to an affordable advanced booster and to enable competition. The third and final phase will be a full and open competition for Design, Development, Test, and Evaluation (DDT&E) of the advanced boosters. There are no existing boosters that can meet the performance requirements for the 130 t class SLS. The expected thrust class of the advanced boosters is potentially double the current 5-segment solid rocket booster capability. These new boosters will enable the flexible path approach to space exploration beyond Earth orbit (BEO), opening up vast opportunities including near-Earth asteroids, Lagrange Points, and Mars. This evolved capability offers large volume for science missions and payloads, will be modular and flexible, and will be right-sized for mission requirements. NASA developed the Advanced Booster Engineering Demonstration and/or Risk Reduction NRA to seek industry participation in reducing risks leading to an affordable advanced booster that meets the SLS performance requirements

  13. NASA's Space Launch System Advanced Booster Engineering Demonstration and Risk Reduction Efforts

    NASA Technical Reports Server (NTRS)

    Crumbly, Christopher M.; May, Todd; Dumbacher, Daniel

    2012-01-01

    The National Aeronautics and Space Administration (NASA) formally initiated the Space Launch System (SLS) development in September 2011, with the approval of the program s acquisition plan, which engages the current workforce and infrastructure to deliver an initial 70 metric ton (t) SLS capability in 2017, while using planned block upgrades to evolve to a full 130 t capability after 2021. A key component of the acquisition plan is a three-phased approach for the first stage boosters. The first phase is to complete the development of the Ares and Space Shuttle heritage 5-segment solid rocket boosters for initial exploration missions in 2017 and 2021. The second phase in the booster acquisition plan is the Advanced Booster Risk Reduction and/or Engineering Demonstration NASA Research Announcement (NRA), which was recently awarded after a full and open competition. The NRA was released to industry on February 9, 2012, and its stated intent was to reduce risks leading to an affordable Advanced Booster and to enable competition. The third and final phase will be a full and open competition for Design, Development, Test, and Evaluation (DDT&E) of the Advanced Boosters. There are no existing boosters that can meet the performance requirements for the 130 t class SLS. The expected thrust class of the Advanced Boosters is potentially double the current 5-segment solid rocket booster capability. These new boosters will enable the flexible path approach to space exploration beyond Earth orbit, opening up vast opportunities including near-Earth asteroids, Lagrange Points, and Mars. This evolved capability offers large volume for science missions and payloads, will be modular and flexible, and will be right-sized for mission requirements. NASA developed the Advanced Booster Engineering Demonstration and/or Risk Reduction NRA to seek industry participation in reducing risks leading to an affordable Advanced Booster that meets the SLS performance requirements. Demonstrations and

  14. InP based solar cells for space application: Reduction of external losses

    NASA Technical Reports Server (NTRS)

    Wu, X.; Coutts, T. J.; Dhere, R. G.; Gessert, T. A.; Dhere, N. G.

    1987-01-01

    Although InP-based solar cells have considerable potential for space applications, it is necessary to improve efficiencies to around the level of GaAs or Si cells before their excellent radiation resistance can be regarded as a dominant advantage. The authors concentrate on indium-tin-oxide/InP cells, presenting data relating to reduction of the contact resistance of the rear surface metallization, reduction of reflectance losses by choosing indium-tin-oxide deposition conditions to give specific optical properties, and reduction of losses associated with the grid. Simultaneous optimization of all of these has led to improved values of Jsc. For devices of approximately 1 cm2 in area, the largest Jsc achieved to date is 28.1 mA/aq cm (AM1.5, SERI/NASA direct normal spectrum, 25 C, total area, 100 mW/sq cm). For this particular cell, the equivalent AM0 value of Jsc was 34.6 mA/sq cm, which appears to be the largest reported for any InP-based cell.

  15. In-Space Propulsion, Logistics Reduction, and Evaluation of Steam Reformer Kinetics: Problems and Prospects

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Palaszewski, B. A.; Kulis, M. J.; Gokoglu, S. A.

    2015-01-01

    Human space missions generate waste materials. A 70-kg crewmember creates a waste stream of 1 kg per day, and a four-person crew on a deep space habitat for a 400+ day mission would create over 1600 kg of waste. Converted into methane, the carbon could be used as a fuel for propulsion or power. The NASA Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) project is investing in space resource utilization with an emphasis on repurposing logistics materials for useful purposes and has selected steam reforming among many different competitive processes as the preferred method for repurposing organic waste into methane. Already demonstrated at the relevant processing rate of 5.4 kg of waste per day, high temperature oxygenated steam consumes waste and produces carbon dioxide, carbon monoxide, and hydrogen which can then be converted into methane catalytically. However, the steam reforming process has not been studied in microgravity. Data are critically needed to understand the mechanisms that allow use of steam reforming in a reduced gravity environment. This paper reviews the relevant literature, identifies gravity-dependent mechanisms within the steam gasification process, and describes an innovative experiment to acquire the crucial kinetic information in a small-scale reactor specifically designed to operate within the requirements of a reduced gravity aircraft flight. The experiment will determine if the steam reformer process is mass-transport limited, and if so, what level of forced convection will be needed to obtain performance comparable to that in 1-g.

  16. Combining Crowding Estimation in Objective and Decision Space With Multiple Selection and Search Strategies for Multi-Objective Evolutionary Optimization.

    PubMed

    Xia, Hu; Zhuang, Jian; Yu, Dehong

    2014-03-01

    Many multi-objective evolutionary algorithms (MOEAs) have been successful in approximating the Pareto Front. However, well-distributed solutions in the objective and decision spaces are still required in many real-life applications. In this paper, a novel MOEA is proposed to this problem. Distinct from other MOEAs, the proposed algorithm suggests a framework, which includes two crowding estimation methods, multiple selection methods for mating and search strategies for variation, to improve the MOEA' s searching ability, and the diversity of its solutions. The algorithm emphasizes the importance of using the decision space and the objective space diversities. The objective space crowding and decision space crowding distances are designed using different ideas. To produce new individuals, three different types of mating selections and their respective search strategies are constructed for the main population and the two sparse populations, with the help of the two crowding measurements. Finally, based on the experimental tests on 17 unconstrained multi-objective optimization problems, the proposed algorithm is demonstrated to have better results compared to several state-of-the-art MOEAs. A detailed analysis on the effectiveness and robustness of the framework is also presented.

  17. A procedure of multiple period searching in unequally spaced time-series with the Lomb-Scargle method

    NASA Technical Reports Server (NTRS)

    Van Dongen, H. P.; Olofsen, E.; VanHartevelt, J. H.; Kruyt, E. W.; Dinges, D. F. (Principal Investigator)

    1999-01-01

    Periodogram analysis of unequally spaced time-series, as part of many biological rhythm investigations, is complicated. The mathematical framework is scattered over the literature, and the interpretation of results is often debatable. In this paper, we show that the Lomb-Scargle method is the appropriate tool for periodogram analysis of unequally spaced data. A unique procedure of multiple period searching is derived, facilitating the assessment of the various rhythms that may be present in a time-series. All relevant mathematical and statistical aspects are considered in detail, and much attention is given to the correct interpretation of results. The use of the procedure is illustrated by examples, and problems that may be encountered are discussed. It is argued that, when following the procedure of multiple period searching, we can even benefit from the unequal spacing of a time-series in biological rhythm research.

  18. Reducing a Knowledge-Base Search Space When Data Are Missing

    NASA Technical Reports Server (NTRS)

    James, Mark

    2007-01-01

    This software addresses the problem of how to efficiently execute a knowledge base in the presence of missing data. Computationally, this is an exponentially expensive operation that without heuristics generates a search space of 1 + 2n possible scenarios, where n is the number of rules in the knowledge base. Even for a knowledge base of the most modest size, say 16 rules, it would produce 65,537 possible scenarios. The purpose of this software is to reduce the complexity of this operation to a more manageable size. The problem that this system solves is to develop an automated approach that can reason in the presence of missing data. This is a meta-reasoning capability that repeatedly calls a diagnostic engine/model to provide prognoses and prognosis tracking. In the big picture, the scenario generator takes as its input the current state of a system, including probabilistic information from Data Forecasting. Using model-based reasoning techniques, it returns an ordered list of fault scenarios that could be generated from the current state, i.e., the plausible future failure modes of the system as it presently stands. The scenario generator models a Potential Fault Scenario (PFS) as a black box, the input of which is a set of states tagged with priorities and the output of which is one or more potential fault scenarios tagged by a confidence factor. The results from the system are used by a model-based diagnostician to predict the future health of the monitored system.

  19. The millimeter wave spectrum of methyl cyanate: a laboratory study and astronomical search in space

    NASA Astrophysics Data System (ADS)

    Kolesniková, L.; Alonso, J. L.; Bermúdez, C.; Alonso, E. R.; Tercero, B.; Cernicharo, J.; Guillemin, J.-C.

    2016-06-01

    Aims: The recent discovery of methyl isocyanate (CH3NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH3OCN) a potential molecule in the interstellar medium. The aim of this work is to fulfill the first requirement for its unequivocal identification in space, i.e. the availability of transition frequencies with high accuracy. Methods: The room-temperature rotational spectrum of methyl cyanate was recorded in the millimeter wave domain from 130 to 350 GHz. All rotational transitions revealed A-E splitting owing to methyl internal rotation and were globally analyzed using the ERHAM program. Results: The data set for the ground torsional state of methyl cyanate exceeds 700 transitions within J'' = 10-35 and K"a= 0-13 and newly derived spectroscopic constants reproduce the spectrum close to the experimental uncertainty. Spectral features of methyl cyanate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methyl cyanate are provided. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00009.SV. Tables 3 and 4 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A75

  20. Primary Class Size Reduction: How Policy Space, Physical Space, and Spatiality Shape What Happens in Real Schools

    ERIC Educational Resources Information Center

    Bascia, Nina; Faubert, Brenton

    2012-01-01

    This article reviews the literature base on class size reduction and proposes a new analytic framework that we believe provides practically useful explanations of how primary class size reduction works. It presents descriptions of classroom practice and grounded explanations for how class size reduction affects educational core activities by…

  1. Targets Need Their Own Personal Space: Effects of Clutter on Multiple-Target Search Accuracy.

    PubMed

    Adamo, Stephen H; Cain, Matthew S; Mitroff, Stephen R

    2015-01-01

    Visual search is an essential task for many lifesaving professions; airport security personnel search baggage X-ray images for dangerous items and radiologists examine radiographs for tumors. Accuracy is critical for such searches; however, there are potentially negative influences that can affect performance; for example, the displays can be cluttered and can contain multiple targets. Previous research has demonstrated that clutter can hurt search performance and a second target is less likely to be detected in a multiple-target search after a first target has been found, which raises a concern-how does clutter affect multiple-target search performance? The current study explored clutter in a multiple-target search paradigm, where there could be one or two targets present, and targets appeared in varying levels of clutter. There was a significant interaction between clutter and target number: Increasing levels of clutter did not affect single-target detection but did reduce detection of a second target. Multiple-target search accuracy is known to be sensitive to contextual influences, and the current results reveal a specific effect wherein clutter disproportionally affected multiple-target search accuracy. These results suggest that the detection and processing of a first target might enhance the masking effects of clutter around a second target.

  2. JAMES WEBB SPACE TELESCOPE CAN DETECT KILONOVAE IN GRAVITATIONAL WAVE FOLLOW-UP SEARCH

    SciTech Connect

    Bartos, I.; Márka, S.; Huard, T. L.

    2016-01-10

    Kilonovae represent an important electromagnetic counterpart for compact binary mergers, which could become the most commonly detected gravitational-wave (GW) source. Follow-up observations of kilonovae, triggered by GW events, are nevertheless difficult due to poor localization by GW detectors and due to their faint near-infrared peak emission, which has limited observational capability. We show that the Near-Infrared Camera (NIRCam) on the James Webb Space Telescope will be able to detect kilonovae within the relevant GW-detection range of ∼200 Mpc in short (≲12-s) exposure times for a week following the merger. Despite this sensitivity, a kilonova search fully covering a fiducial localized area of 10 deg{sup 2} will not be viable with NIRCam due to its limited field of view. However, targeted surveys may be developed to optimize the likelihood of discovering kilonovae efficiently within limited observing time. We estimate that a survey of 10 deg{sup 2} focused on galaxies within 200 Mpc would require about 13 hr, dominated by overhead times; a survey further focused on galaxies exhibiting high star formation rates would require ∼5 hr. The characteristic time may be reduced to as little as ∼4 hr, without compromising the likelihood of detecting kilonovae, by surveying sky areas associated with 50%, rather than 90%, confidence regions of 3 GW events, rather than a single event. Upon the detection and identification of a kilonova, a limited number of NIRCam follow-up observations could constrain the properties of matter ejected by the binary and the equation of state of dense nuclear matter.

  3. Optimal search strategies of space-time coupled random walkers with finite lifetimes.

    PubMed

    Campos, D; Abad, E; Méndez, V; Yuste, S B; Lindenberg, K

    2015-05-01

    We present a simple paradigm for detection of an immobile target by a space-time coupled random walker with a finite lifetime. The motion of the walker is characterized by linear displacements at a fixed speed and exponentially distributed duration, interrupted by random changes in the direction of motion and resumption of motion in the new direction with the same speed. We call these walkers "mortal creepers." A mortal creeper may die at any time during its motion according to an exponential decay law characterized by a finite mean death rate ω(m). While still alive, the creeper has a finite mean frequency ω of change of the direction of motion. In particular, we consider the efficiency of the target search process, characterized by the probability that the creeper will eventually detect the target. Analytic results confirmed by numerical results show that there is an ω(m)-dependent optimal frequency ω=ω(opt) that maximizes the probability of eventual target detection. We work primarily in one-dimensional (d=1) domains and examine the role of initial conditions and of finite domain sizes. Numerical results in d=2 domains confirm the existence of an optimal frequency of change of direction, thereby suggesting that the observed effects are robust to changes in dimensionality. In the d=1 case, explicit expressions for the probability of target detection in the long time limit are given. In the case of an infinite domain, we compute the detection probability for arbitrary times and study its early- and late-time behavior. We further consider the survival probability of the target in the presence of many independent creepers beginning their motion at the same location and at the same time. We also consider a version of the standard "target problem" in which many creepers start at random locations at the same time.

  4. Space optical and low-frequency radio searches for Earth-crossing asteroids and comets

    NASA Astrophysics Data System (ADS)

    Hills, J. G.; Gisler, G. R.

    1993-06-01

    Earth-crossing asteroids (ECA's) are small and backscatter strongly, so they are usually discovered near opposition during close approaches to Earth. This opposition effect produces strong biases in Earth-based searches for ECAS, particularly for Atens. An observing site much closer to the sun than the orbit of Earth, such as a satellite orbiting Venus or telescopes on Mercury, would not suffer this bias. All Atens that cross the orbit of Earth would be observable near opposition from these sites, so a survey from them would not systematically miss any large ECAS. A satellite at the Lagrangian point between the Earth and the sun would be effective in detecting objects in the final day before they hit Earth including asteroids and long-period comets that approach Earth from the sunward side. Outgassing comets present large cross sections to the solar wind. Spacecraft have observed low-frequency radio emission produced by the wiggling of the magnetic field in the solar wind as it sweeps past comets. Asteroids are expected to emit similar radio emission at lower power. This radiation may be observable by a radio array in space or on the moon. A satellite at the Lagrangian point could also detect the downstream solar wind wakes of comets and asteroids that approach Earth from the direction of the sun. Military surveillance satellites may be used to observe the fragmentation of large meteoroids in the atmosphere. Because it observes the entire atmosphere of Earth and is not affected by local weather conditions, such a surveillance network has a much larger cross section than a ground survey for observing the rare, large meteors that more closely approach the size of those that cause economic damage.

  5. A Hybrid Optimization Framework with POD-based Order Reduction and Design-Space Evolution Scheme

    NASA Astrophysics Data System (ADS)

    Ghoman, Satyajit S.

    The main objective of this research is to develop an innovative multi-fidelity multi-disciplinary design, analysis and optimization suite that integrates certain solution generation codes and newly developed innovative tools to improve the overall optimization process. The research performed herein is divided into two parts: (1) the development of an MDAO framework by integration of variable fidelity physics-based computational codes, and (2) enhancements to such a framework by incorporating innovative features extending its robustness. The first part of this dissertation describes the development of a conceptual Multi-Fidelity Multi-Strategy and Multi-Disciplinary Design Optimization Environment (M3 DOE), in context of aircraft wing optimization. M 3 DOE provides the user a capability to optimize configurations with a choice of (i) the level of fidelity desired, (ii) the use of a single-step or multi-step optimization strategy, and (iii) combination of a series of structural and aerodynamic analyses. The modularity of M3 DOE allows it to be a part of other inclusive optimization frameworks. The M 3 DOE is demonstrated within the context of shape and sizing optimization of the wing of a Generic Business Jet aircraft. Two different optimization objectives, viz. dry weight minimization, and cruise range maximization are studied by conducting one low-fidelity and two high-fidelity optimization runs to demonstrate the application scope of M3 DOE. The second part of this dissertation describes the development of an innovative hybrid optimization framework that extends the robustness of M 3 DOE by employing a proper orthogonal decomposition-based design-space order reduction scheme combined with the evolutionary algorithm technique. The POD method of extracting dominant modes from an ensemble of candidate configurations is used for the design-space order reduction. The snapshot of candidate population is updated iteratively using evolutionary algorithm technique of

  6. Searching the Future for the Legal Regime of Space Activities: the Need for Unification of National Space Legislation' Provisions

    NASA Astrophysics Data System (ADS)

    Negoda, S. A.

    2002-01-01

    space activities. For the future legal regime of space activities it is vital to preserve the existed principles and main provisions of the international space law. related legislations are developing rapidly. They become serious instrument for legal regulation of space activities. those projects with a foreign party involvement. Quite often partners in international space projects agree to choice a domestic law of one of them. They do this for defining a certain organizational and/or contractual issue (disputes settlement, for example) of the project. that such practice will spread widely. could help to preserve the existed important provisions of international space law (responsibility of states for their national activities, for instance). development of international space private law. We believe that solely special laws and regulations of national legislations could not regulate modern space activities. Being more and more commercial, space activities are becoming a real part of "downed to Earth" commercial activities. Therefore, in many countries provisions of civil, commercial, investment and other branches of national law are applied to such activities. which could low possible risks of such activities and to control them. Such unification seems to be suitable in the following fields: 1)implementation of provisions of international space law in national space laws; 2)definition of unified terminology, accepted by national laws of all parties; 3)unification in national legislations of a certain standards (insurance rates and rules, for instance); 4)unification in national laws of issues related to liability (for instance, a mutual wave of liability in certain types of 5)implementation in national laws of unified rules and procedures of space-related commercial disputes settlement; 6)unification of mechanisms for protection of space-related intellectual property. unification of their provisions. Special attention is paid to provisions of private law

  7. Empirically extending the range of validity of parameter-space metrics for all-sky searches for gravitational-wave pulsars

    NASA Astrophysics Data System (ADS)

    Wette, Karl

    2016-12-01

    All-sky searches for gravitational-wave pulsars are generally limited in sensitivity by the finite availability of computing resources. Semicoherent searches are a common method of maximizing search sensitivity given a fixed computing budget. The work of Wette and Prix [Phys. Rev. D 88, 123005 (2013)] and Wette [Phys. Rev. D 92, 082003 (2015)] developed a semicoherent search method which uses metrics to construct the banks of pulsar signal templates needed to search the parameter space of interest. In this work we extend the range of validity of the parameter-space metrics using an empirically derived relationship between the resolution (or mismatch) of the template banks and the mismatch of the overall search. This work has important consequences for the optimization of metric-based semicoherent searches at fixed computing cost.

  8. The economic benefits of rainwater-runoff reduction by urban green spaces: a case study in Beijing, China.

    PubMed

    Zhang, Biao; Xie, Gaodi; Zhang, Canqiang; Zhang, Jing

    2012-06-15

    Urbanization involves the replacement of vegetated surfaces with impervious built surfaces, and it often results in an increase in the rate and volume of rainwater surface runoff. Urban green spaces play a positive role in rainwater-runoff reduction. However, few studies have explored the benefits of rainwater-runoff reduction by urban green spaces. Based on inventory data of urban green spaces in Beijing, the paper evaluated the economic benefits of rainwater-runoff reduction by urban green spaces, using the rainwater-runoff-coefficient method as well as the economic valuation methods. The results showed that, 2494 cubic meters of potential runoff was reduced per hectare of green area and a total volume of 154 million cubic meters rainwater was stored in these urban green spaces, which almost corresponds to the annual water needs of the urban ecological landscape in Beijing. The total economic benefit was 1.34 billion RMB in 2009 (RMB: Chinese currency, US$1=RMB6.83), which is equivalent to three-quarters of the maintenance cost of Beijing's green spaces; the value of rainwater-runoff reduction was 21.77 thousand RMB per hectare. In addition, the benefits in different districts and counties were ranked in the same order as urban green areas, and the average benefits per hectare of green space showed different trends, which may be related to the impervious surface index in different regions. This research will contribute to an understanding of the role that Beijing's green spaces play in rainwater regulation and in the creation and scientific management of urban green spaces.

  9. Smart LED lighting for major reductions in power and energy use for plant lighting in space

    NASA Astrophysics Data System (ADS)

    Poulet, Lucie

    optimizing conditions with red and blue LED lighting required 12 times less energy than with a traditional high-intensity discharge lighting system. This study paves the way for refinement of the smart lighting system and further, major reductions in ESM for space life-support systems and for ground-based controlled-environment agriculture. Project supported by NASA grant number NNX09AL99G.

  10. Multi scale Disaster Risk Reduction Systems Space and Community based Experiences over HKH Region

    NASA Astrophysics Data System (ADS)

    Gurung, D. R.; Shrestha, M.; Shrestha, N.; Debnath, B.; Jishi, G.; Bajracharya, R.; Dhonju, H. K.; Pradhan, S.

    2014-11-01

    An increasing trend in the recurrence of natural disasters and associated impacts due to Floods, Glacier Lake out bursts, landslides and forest fire is reported over Hindu Kush Himalyan (HKH) region. Climate change and anthropogenic coupled factors are identified as primary factors for such increased vulnerability. The large degree of poverty, lack of infrastructure, poor accessibility and uncertainties involved in understanding high altitude land surface and climate dynamics poses serious challenges in reducing disaster vulnerability and mitigating disaster impacts. In this context effective development of Disaster Risk Reduction (DRR) protocols and mechanisms have been realized as an urgent need. The paper presents the adoption and experiences of multi scale DRR systems across different Himalayan member countries ranging from community based indigenous early warning to space based emergency response and decision support systems. The Establishment of a Regional Flood Information System (HKH-HYCOS) over Ganges-Brahmaputra-Meghna (GBM) and Indus river basins promoted the timely exchange of flood data and information for the reduction of flood vulnerability within and among the participating countries. Satellite based forest fire alert systems evoked significant response among diverse stakeholders to optimize fire incidence and control. Satellite rainfall estimation products, satellite altimetry based flood early warning systems, flood inundation modelling and products, model derived hydrology flow products from different global data-sharing networks constitutes diverse information to support multi scale DRR systems. Community-based Flood Early Warning System (FEWS) enabled by wireless technology established over the Singara and Jiadhal rivers in Assam also stands as one of the promising examples of minimizing flood risk. Disaster database and information system and decision support tools in Nepal serves as potential tool to support diverse stakeholders.

  11. Update on Risk Reduction Activities for a Liquid Advanced Booster for NASA's Space Launch System

    NASA Technical Reports Server (NTRS)

    Crocker, Andrew M.; Doering, Kimberly B; Meadows, Robert G.; Lariviere, Brian W.; Graham, Jerry B.

    2015-01-01

    The stated goals of NASA's Research Announcement for the Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) are to reduce risks leading to an affordable Advanced Booster that meets the evolved capabilities of SLS; and enable competition by mitigating targeted Advanced Booster risks to enhance SLS affordability. Dynetics, Inc. and Aerojet Rocketdyne (AR) formed a team to offer a wide-ranging set of risk reduction activities and full-scale, system-level demonstrations that support NASA's ABEDRR goals. For NASA's SLS ABEDRR procurement, Dynetics and AR formed a team to offer a series of full-scale risk mitigation hardware demonstrations for an affordable booster approach that meets the evolved capabilities of the SLS. To establish a basis for the risk reduction activities, the Dynetics Team developed a booster design that takes advantage of the flight-proven Apollo-Saturn F-1. Using NASA's vehicle assumptions for the SLS Block 2, a two-engine, F-1-based booster design delivers 150 mT (331 klbm) payload to LEO, 20 mT (44 klbm) above NASA's requirements. This enables a low-cost, robust approach to structural design. During the ABEDRR effort, the Dynetics Team has modified proven Apollo-Saturn components and subsystems to improve affordability and reliability (e.g., reduce parts counts, touch labor, or use lower cost manufacturing processes and materials). The team has built hardware to validate production costs and completed tests to demonstrate it can meet performance requirements. State-of-the-art manufacturing and processing techniques have been applied to the heritage F-1, resulting in a low recurring cost engine while retaining the benefits of Apollo-era experience. NASA test facilities have been used to perform low-cost risk-reduction engine testing. In early 2014, NASA and the Dynetics Team agreed to move additional large liquid oxygen/kerosene engine work under Dynetics' ABEDRR contract. Also led by AR, the

  12. Partition search

    SciTech Connect

    Ginsberg, M.L.

    1996-12-31

    We introduce a new form of game search called partition search that incorporates dependency analysis, allowing substantial reductions in the portion of the tree that needs to be expanded. Both theoretical results and experimental data are presented. For the game of bridge, partition search provides approximately as much of an improvement over existing methods as {alpha}-{beta} pruning provides over minimax.

  13. Space-fractional Fokker-Planck equation and optimization of random search processes in the presence of an external bias

    NASA Astrophysics Data System (ADS)

    Palyulin, Vladimir V.; Chechkin, Aleksei V.; Metzler, Ralf

    2014-11-01

    Based on the space-fractional Fokker-Planck equation with a δ-sink term, we study the efficiency of random search processes based on Lévy flights with power-law distributed jump lengths in the presence of an external drift, for instance, an underwater current, an airflow, or simply the preference of the searcher based on prior experience. While Lévy flights turn out to be efficient search processes when the target is upstream relative to the starting point, in the downstream scenario, regular Brownian motion turns out to be advantageous. This is caused by the occurrence of leapovers of Lévy flights, due to which Lévy flights typically overshoot a point or small interval. Studying the solution of the fractional Fokker-Planck equation, we establish criteria when the combination of the external stream and the initial distance between the starting point and the target favours Lévy flights over the regular Brownian search. Contrary to the common belief that Lévy flights with a Lévy index α = 1 (i.e. Cauchy flights) are optimal for sparse targets, we find that the optimal value for α may range in the entire interval (1, 2) and explicitly include Brownian motion as the most efficient search strategy overall.

  14. NEAT: an astrometric space telescope to search for habitable exoplanets in the solar neighborhood

    NASA Astrophysics Data System (ADS)

    Crouzier, A.; Malbet, F.; Kern, P.; Feautrier, P.; Preiss, O.; Martin, G.; Henault, F.; Stadler, E.; Lafrasse, S.; Behar, E.; Saintpe, M.; Dupont, J.; Potin, S.; Lagage, P.-O.; Cara, C.; Leger, A.; Leduigou, J.-M.; Shao, M.; Goullioud, R.

    2014-03-01

    radial velocities and direct imaging, it will explore in a quasi systematic way the nearby planetary systems. The resulting catalog of planetary systems will be very useful to constrain planetary formation models. The second objective is to find very close Earth analogs. These will be top priority targets for a spectroscopic mission aimed at detecting biomarquers. The current activities related to NEAT revolve around 3 themes: i) a lab demonstration: an optical bench replicates the NEAT optical configuration and metrology system in order to demonstrate the feasibility of measuring centroids with a differential accuracy of 5 µpixels (corresponding to 0.3 micro arc sec on sky) ii) a definition phase study of the NEAT mission done by CNES (the "French Space Agency") iii) an end to end simulation of the NEAT data reduction pipeline: from astrometric and RVs measurements to planets All of these activities are focused on the need to answer the next ESA call for M class missions in 2014 with an improved NEAT concept.

  15. Militarization of space. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-04-01

    The bibliography contains citations concerning existing and projected military use of space by the United States and foreign powers. Long term strategies, technical feasibility studies, and the use of space in tactical operations are considered. Space weapons, including high-energy lasers, shuttle operations, and the Strategic Defense Initiative (SDI) program are examined. (Contains 250 citations and includes a subject term index and title list.)

  16. The chemist as astronaut: searching for biologically useful space in the chemical universe.

    PubMed

    Triggle, David J

    2009-08-01

    Chemical space whether defined by small molecules or large proteins is larger than can be usefully explored. One of the challenges of drug discovery is thus the definition of the overlap between chemical space, biologically useful space and pharmacological space and how this may be employed in the discovery of new small molecule drugs. Despite the decrease in drug discovery productivity in recent years there is no shortage of targets for small molecule intervention, including stroke, pain, neurodegenerative diseases, inflammation and bacterial and viral infections. Only an extremely small fraction of available chemical space has thus far been explored and it is likely that prior synthetic constraints and bias to existing frameworks and scaffolds have contributed to this. Several approaches are being employed to explore more fruitful paths to discovery. These include recognition that existing therapeutic entities already occupy validated pharmacological space and thus are good leads, the use of molecular fragments that permits a broader exploration of chemical space, and the role of templates that permit fragments to combine to generate active species. Finally, a new focus on natural product-like scaffolds from both synthetic methodologies and the genetic reengineering of biosynthetic pathways is likely to prove valuable. However the exploration of chemical space will alone not solve the current deficit in drug discovery productivity. It is necessary to recognize that cellular environments are not the dilute homogeneous solutions of many screening systems and that a more integrated systems approach will serve to maximize any success of chemical space exploration.

  17. Effects of Link Annotations on Search Performance in Layered and Unlayered Hierarchically Organized Information Spaces.

    ERIC Educational Resources Information Center

    Fraser, Landon; Locatis, Craig

    2001-01-01

    Investigated the effects of link annotations on high school user search performance in Web hypertext environments having deep (layered) and shallow link structures. Results confirmed previous research that shallow link structures are better than deep (layered) link structures, and also showed that annotations had virtually no effect on search…

  18. Design of combinatorial libraries for the exploration of virtual hits from fragment space searches with LoFT.

    PubMed

    Lessel, Uta; Wellenzohn, Bernd; Fischer, J Robert; Rarey, Matthias

    2012-02-27

    A case study is presented illustrating the design of a focused CDK2 library. The scaffold of the library was detected by a feature trees search in a fragment space based on reactions from combinatorial chemistry. For the design the software LoFT (Library optimizer using Feature Trees) was used. The special feature called FTMatch was applied to restrict the parts of the queries where the reagents are permitted to match. This way a 3D scoring function could be simulated. Results were compared with alternative designs by GOLD docking and ROCS 3D alignments.

  19. A Novel Method Using Abstract Convex Underestimation in Ab-Initio Protein Structure Prediction for Guiding Search in Conformational Feature Space.

    PubMed

    Hao, Xiao-Hu; Zhang, Gui-Jun; Zhou, Xiao-Gen; Yu, Xu-Feng

    2016-01-01

    To address the searching problem of protein conformational space in ab-initio protein structure prediction, a novel method using abstract convex underestimation (ACUE) based on the framework of evolutionary algorithm was proposed. Computing such conformations, essential to associate structural and functional information with gene sequences, is challenging due to the high-dimensionality and rugged energy surface of the protein conformational space. As a consequence, the dimension of protein conformational space should be reduced to a proper level. In this paper, the high-dimensionality original conformational space was converted into feature space whose dimension is considerably reduced by feature extraction technique. And, the underestimate space could be constructed according to abstract convex theory. Thus, the entropy effect caused by searching in the high-dimensionality conformational space could be avoided through such conversion. The tight lower bound estimate information was obtained to guide the searching direction, and the invalid searching area in which the global optimal solution is not located could be eliminated in advance. Moreover, instead of expensively calculating the energy of conformations in the original conformational space, the estimate value is employed to judge if the conformation is worth exploring to reduce the evaluation time, thereby making computational cost lower and the searching process more efficient. Additionally, fragment assembly and the Monte Carlo method are combined to generate a series of metastable conformations by sampling in the conformational space. The proposed method provides a novel technique to solve the searching problem of protein conformational space. Twenty small-to-medium structurally diverse proteins were tested, and the proposed ACUE method was compared with It Fix, HEA, Rosetta and the developed method LEDE without underestimate information. Test results show that the ACUE method can more rapidly and more

  20. Assessment of Technology Readiness Level of a Carbon Dioxide Reduction Assembly (CRA) for use on International Space Station

    NASA Technical Reports Server (NTRS)

    Murdoch, Karen; Smith, Fred; Perry, Jay; Green, Steve

    2004-01-01

    When technologies are traded for incorporation into vehicle systems to support a specific mission scenario, they are often assessed in terms of Technology Readiness Level (TRL). TRL is based on three major categories of Core Technology Components, Ancillary Hardware and System Maturity, and Control and Control Integration. This paper describes the Technology Readiness Level assessment of the Carbon Dioxide Reduction Assembly (CRA) for use on the International Space Station. A team comprising of the NASA Johnson Space Center, Marshall Space Flight Center, Southwest Research Institute and Hamilton Sundstrand Space Systems International have been working on various aspects of the CRA to bring its TRL from 4/5 up to 6. This paper describes the work currently being done in the three major categories. Specific details are given on technology development of the Core Technology Components including the reactor, phase separator and CO2 compressor.

  1. The Siegel Upper Half Space is a Marsden-Weinstein Quotient: Symplectic Reduction and Gaussian Wave Packets

    NASA Astrophysics Data System (ADS)

    Ohsawa, Tomoki

    2015-09-01

    We show that the Siegel upper half space is identified with the Marsden-Weinstein quotient obtained by symplectic reduction of the cotangent bundle with O(2 d)-symmetry. The reduced symplectic form on corresponding to the standard symplectic form on turns out to be a constant multiple of the symplectic form on obtained by Siegel. Our motivation is to understand the geometry behind two different formulations of the Gaussian wave packet dynamics commonly used in semiclassical mechanics. Specifically, we show that the two formulations are related via the symplectic reduction.

  2. Indirect Search of Dark Matter in Space: Theoretical and Phenomenological Aspects

    NASA Astrophysics Data System (ADS)

    Cirelli, Marco

    Dark Matter constitutes more that 80% of the total amount of matter in the Universe, yet almost nothing is known about its nature. A powerful investigation technique is that of searching for the products of annihilations of Dark Matter particles in the galactic halo, on top of the ordinary cosmic rays. Recent data from the PAMELA and FERMI satellites and a number of balloon experiment have reported unexpected excesses in the measured uxes of cosmic rays. Are these the first direct evidences for Dark Matter? If yes, which DM models and candidates can explain these anomalies (in terms of annihilations) and what do they imply for future searches? What are the constraints from gamma rays measurements and cosmology? [Saclay T-09/222, CERN-PH-TH/2009-252

  3. Cooperative learning over composite search spaces: Experiences with a multi-agent design system

    SciTech Connect

    Prasad, M.V.N.; Lesser, V.R.; Lander, S.E.

    1996-12-31

    We suggest the use of two learning techniques - short term and long term - to enhance search efficiency in a multi-agent design system by letting the agents learn about non-local requirements on the local search process. The first technique allows an agent to accumulate and apply constraining information about global problem solving, gathered as a result of agent communication, to further problem solving within the same problem instance. The second technique is used to classify problem instances and appropriately index and retrieve constraining information to apply to new problem instances. These techniques will be presented within the context of a multi-agent parametric-design application called STEAM. We show that learning conclusively improves solution quality and processing-time results.

  4. Intelligent search and retrieval of a large multimedia knowledgebase for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Clapis, Paul J.; Byers, William S.

    1990-01-01

    A document-retrieval assistant (DRA) in a microcomputer format is described which incorporates hypertext and natural language capabilities. Hypertext is used to introduce an intelligent search capability, and the natural-language interface permits access to specific data without the use of keywords. The DRA can be used to access and 'browse' the large multimedia database that is composed of project documentation from the HST.

  5. Answers in search of a question: 'proofs' of the tri-dimensionality of space

    NASA Astrophysics Data System (ADS)

    Callender, Craig

    From Kant's first published work to recent articles in the physics literature, philosophers and physicists have long sought an answer to the question: Why does space have three dimensions? In this paper, I will flesh out Kant's claim with a brief detour through Gauss' law. I then describe Büchel's version of the common argument that stable orbits are possible only if space is three dimensional. After examining objections by Russell and van Fraassen, I develop three original criticisms of my own. These criticisms are relevant to both historical and contemporary proofs of the dimensionality of space (in particular, a recent one by Burgbacher, Lämmerzahl, and Macias). In general, I argue that modern "proofs" of the dimensionality of space have gone off track.

  6. Projection space denoising with bilateral filtering and CT noise modeling for dose reduction in CT

    SciTech Connect

    Manduca, Armando; Yu Lifeng; Trzasko, Joshua D.; Khaylova, Natalia; Kofler, James M.; McCollough, Cynthia M.; Fletcher, Joel G.

    2009-11-15

    Purpose: To investigate a novel locally adaptive projection space denoising algorithm for low-dose CT data. Methods: The denoising algorithm is based on bilateral filtering, which smooths values using a weighted average in a local neighborhood, with weights determined according to both spatial proximity and intensity similarity between the center pixel and the neighboring pixels. This filtering is locally adaptive and can preserve important edge information in the sinogram, thus maintaining high spatial resolution. A CT noise model that takes into account the bowtie filter and patient-specific automatic exposure control effects is also incorporated into the denoising process. The authors evaluated the noise-resolution properties of bilateral filtering incorporating such a CT noise model in phantom studies and preliminary patient studies with contrast-enhanced abdominal CT exams. Results: On a thin wire phantom, the noise-resolution properties were significantly improved with the denoising algorithm compared to commercial reconstruction kernels. The noise-resolution properties on low-dose (40 mA s) data after denoising approximated those of conventional reconstructions at twice the dose level. A separate contrast plate phantom showed improved depiction of low-contrast plates with the denoising algorithm over conventional reconstructions when noise levels were matched. Similar improvement in noise-resolution properties was found on CT colonography data and on five abdominal low-energy (80 kV) CT exams. In each abdominal case, a board-certified subspecialized radiologist rated the denoised 80 kV images markedly superior in image quality compared to the commercially available reconstructions, and denoising improved the image quality to the point where the 80 kV images alone were considered to be of diagnostic quality. Conclusions: The results demonstrate that bilateral filtering incorporating a CT noise model can achieve a significantly better noise-resolution trade

  7. Great SEP events and space weather: 1. Experience of automatically searching for event beginnings; probabilities of false and missed events

    NASA Astrophysics Data System (ADS)

    Applbaum, David; Dorman, Lev; Pustil'Nik, Lev; Sternlieb, Abraham; Zagnetko, Alexander; Zukerman, Igor

    It is well known that during great SEP events, fluxes of energetic particles can be so big that the memory of computers and other electronics in space may be destroyed, and satellites and spacecraft may cease to function. According to the NOAA Space Weather Prediction Cen-ter, the following scales constitute dangerous solar radiation storms: S5-extreme (flux level of particles with energy ∼ 10 MeV more than 105 ); S4 - severe(f luxmorethan104 ); andS3 - strong(f luxmorethan103 ). In these persiods, it is necessary to switch off some of the electronics for a few hours energy particles (meaning those with a few GeV/nucleon and higher), whose transportation to Earthfrom the S20 minutes after they accelerate and escape into the solar wind) than the main bulk of the smaller energy particle 60 minutes later). Here we describe the principles and experience of the automatic function of the "SEP - Search" program. The positive result, showing the exact beginning of an SEP event on the Emilio Segre Observ 10.8GV ), is determined now automatically by simultaneously increasing by 2.5 St.Dev. in two sections of the ne search "programnext uses 1-mindata for checking whether or not the observed increase reflects the beginning Research "automatically starts to work online. We determine also the probabilities of false and missed alerts.

  8. EEG/ERP adaptive noise canceller design with controlled search space (CSS) approach in cuckoo and other optimization algorithms.

    PubMed

    Ahirwal, M K; Kumar, Anil; Singh, G K

    2013-01-01

    This paper explores the migration of adaptive filtering with swarm intelligence/evolutionary techniques employed in the field of electroencephalogram/event-related potential noise cancellation or extraction. A new approach is proposed in the form of controlled search space to stabilize the randomness of swarm intelligence techniques especially for the EEG signal. Swarm-based algorithms such as Particles Swarm Optimization, Artificial Bee Colony, and Cuckoo Optimization Algorithm with their variants are implemented to design optimized adaptive noise canceler. The proposed controlled search space technique is tested on each of the swarm intelligence techniques and is found to be more accurate and powerful. Adaptive noise canceler with traditional algorithms such as least-mean-square, normalized least-mean-square, and recursive least-mean-square algorithms are also implemented to compare the results. ERP signals such as simulated visual evoked potential, real visual evoked potential, and real sensorimotor evoked potential are used, due to their physiological importance in various EEG studies. Average computational time and shape measures of evolutionary techniques are observed 8.21E-01 sec and 1.73E-01, respectively. Though, traditional algorithms take negligible time consumption, but are unable to offer good shape preservation of ERP, noticed as average computational time and shape measure difference, 1.41E-02 sec and 2.60E+00, respectively.

  9. CARBON DIOXIDE REDUCTION CONTACTORS IN SPACE VEHICLES AND OTHER ENCLOSED STRUCTURES,

    DTIC Science & Technology

    CONTROLLED ATMOSPHERES, CARBON DIOXIDE , REMOVAL, LIFE SUPPORT SYSTEMS, SPACE ENVIRONMENTS, CONFINED ENVIRONMENTS, OXYGEN CONSUMPTION, REGENERATION(ENGINEERING), CHEMISORPTION, MASS TRANSFER, FLUID MECHANICS, CENTRIFUGES.

  10. The First Deep Space Cubesat Broadband IR Spectrometer, Lunarcubes, and the Search for Lunar Volatiles

    NASA Technical Reports Server (NTRS)

    Clark, P. E.; Malphrus, Ben; Reuter, Dennis; MacDowall, Robert; Folta, David; Hurford, Terry; Brambora, Cliff; Farrell, William

    2017-01-01

    BIRCHES is the compact broadband IR spectrometer of the Lunar Ice Cube mission. Lunar Ice Cube is one of 13 6U cubesats that will be deployed by EM1 in cislunar space, qualifying as lunarcubes. The LunarCube paradigm is a proposed approach for extending the affordable CubeSat standard to support access to deep space via cis-lunar/lunar missions. Because the lunar environment contains analogs of most solar system environments, the Moon is an ideal target for both testing critical deep space capabilities and understanding solar system formation and processes. Effectively, as developments are occurring in parallel, 13 prototype deep space cubesats are being flown for EM1. One useful outcome of this 'experiment' will be to determine to what extent it is possible to develop a lunarcube 'bus' with standardized interfaces to all subsystems using reasonable protocols for a variety of payloads. The lunar ice cube mission was developed as the test case in a GSFC R&D study to determine whether the cubesat paradigm could be applied to deep space, science requirements driven missions, and BIRCHES was its payload. JPL's Lunar Flashlight, and Arizona State University's LunaH-Map, both also EM1 lunar orbiters, will also be deployed from EM1 and provide complimentary observations to be used in understanding volatile dynamics in the same time frame.

  11. Space Launch System NASA Research Announcement Advanced Booster Engineering Demonstration and/or Risk Reduction

    NASA Technical Reports Server (NTRS)

    Crumbly, Christopher M.; Craig, Kellie D.

    2011-01-01

    The intent of the Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) effort is to: (1) Reduce risks leading to an affordable Advanced Booster that meets the evolved capabilities of SLS (2) Enable competition by mitigating targeted Advanced Booster risks to enhance SLS affordability. Key Concepts (1) Offerors must propose an Advanced Booster concept that meets SLS Program requirements (2) Engineering Demonstration and/or Risk Reduction must relate to the Offeror s Advanced Booster concept (3) NASA Research Announcement (NRA) will not be prescriptive in defining Engineering Demonstration and/or Risk Reduction

  12. Orienting of visuo-spatial attention in complex 3D space: Search and detection

    PubMed Central

    Ogawa, Akitoshi; Macaluso, Emiliano

    2015-01-01

    The ability to detect changes in the environment is necessary for appropriate interactions with the external world. Changes in the background go more unnoticed than foreground changes, possibly because attention prioritizes processing of foreground/near stimuli. Here, we investigated the detectability of foreground and background changes within natural scenes and the influence of stereoscopic depth cues on this. Using a flicker paradigm, we alternated a pair of images that were exactly same or differed for one single element (i.e., a color change of one object in the scene). The participants were asked to find the change that occurred either in a foreground or background object, while viewing the stimuli either with binocular and monocular cues (bmC) or monocular cues only (mC). The behavioral results showed faster and more accurate detections for foreground changes and overall better performance in bmC than mC conditions. The imaging results highlighted the involvement of fronto-parietal attention controlling networks during active search and target detection. These attention networks did not show any differential effect as function of the presence/absence of the binocular cues, or the detection of foreground/background changes. By contrast, the lateral occipital cortex showed greater activation for detections in foreground compared to background, while area V3A showed a main effect of bmC vs. mC, specifically during search. These findings indicate that visual search with binocular cues does not impose any specific requirement on attention-controlling fronto-parietal networks, while the enhanced detection of front/near objects in the bmC condition reflects bottom-up sensory processes in visual cortex. Hum Brain Mapp 36:2231–2247, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:25691253

  13. Imaging enhancement by reduction of mask topography induced phase aberrations for horizontal 1D spaces under D90Y illumination

    NASA Astrophysics Data System (ADS)

    Last, T.; de Winter, L.; Finders, J.

    2015-10-01

    EUV reticles need to be considered as complex optical elements in the beam path with considerable impact on lithography. Here we present a work flow for absorber optimization by applying a complementary approach of investigating lithographic metrics and mask-topography induced phase aberrations. In the first part this complementary approach is applied to find an optimum thickness of a typical Ta-based absorber for imaging horizontal spaces through pitch. And although an absorber thickness of around 70 nm is found to be preferable for this particular application, the thickness choice leads to conflicting results for the general printability of 10 nm technology node features. Hence we show that a moderate reduction of the absorber thickness can be allowed when the mask bias of these features is optimized appropriately. The moderate thickness reduction already allows for the mitigation of some of the conflicting imaging aspects. In the second part we expand the workflow by analyzing phase aberrations in n & k material space. This phase-based optical property screening shows that an alternative absorber based on materials such as Ni with k higher than Ta show superior best focus and contrast metrics. These alternative absorber embodiments would allow the overall reduction of M3D effects and adverse application dependencies of current Ta-based absorbers due to a combination of thickness reduction and enhancement of absorption.

  14. Guidelines for contingency planning NASA (National Aeronautics and Space Administration) ADP security risk reduction decision studies

    NASA Technical Reports Server (NTRS)

    Tompkins, F. G.

    1984-01-01

    Guidance is presented to NASA Computer Security Officials for determining the acceptability or unacceptability of ADP security risks based on the technical, operational and economic feasibility of potential safeguards. The risk management process is reviewed as a specialized application of the systems approach to problem solving and information systems analysis and design. Reporting the results of the risk reduction analysis to management is considered. Report formats for the risk reduction study are provided.

  15. The Oceanic Researcher and the Search for a Space in Comparative and International Education

    ERIC Educational Resources Information Center

    Johansson-Fua, Seu'ula

    2016-01-01

    This paper argues that, despite the increasingly espoused centrality of culture and context to the field of comparative and international education, the voices from within the context remain silent and absent from the literature on comparative and international education. This paper explores the various spaces in which an Oceanic researcher may…

  16. NASA's New Laser Risk Reduction Program For Future Space Lidar Missions

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J.; Singh, Upendra N.; Heaps, William S.; Cazeau, Tony

    2002-01-01

    NASA has been performing ground, airborne, and space-based scientific measurements since it was formed in 1958. Initial ground and airborne measurements were made with in situ instruments. By necessity, initial earth observation space-based missions were accomplished with passive remote sensing. Active microwave radar was added to the sensor repertoire in the late 1970s. A few key measurements important to NASA remain unaccomplished, however, despite the passive and radar successes. These critical measurements include space-based altimetry; and high spatial resolution profiling of aerosol properties, wind velocity, clouds, and molecular concentrations. Fortunately, a new technology, active optical radar or laser radar or lidar, has matured to the point that the last decade has seen a growing consideration of lidar for space missions. Part of the surge in consideration of lidar has been the tremendous progress in solid-state lasers fueled by advances in crystal growth quality and pump laser diode technology.

  17. 14 CFR 1206.702 - Waiver or reduction of fees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Waiver or reduction of fees. 1206.702 Section 1206.702 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION AVAILABILITY OF AGENCY RECORDS TO MEMBERS OF THE PUBLIC Search, Review, and Duplication Fees § 1206.702 Waiver...

  18. Marine Microbial Mats and the Search for Evidence of Life in Deep Time and Space

    NASA Technical Reports Server (NTRS)

    Des Marais, David J.

    2011-01-01

    Cyanobacterial mats in extensive seawater evaporation ponds at Guerrero Negro, Baja California, Mexico, have been excellent subjects for microbial ecology research. The studies reviewed here have documented the steep and rapidly changing environmental gradients experienced by mat microorganisms and the very high rates of biogeochemical processes that they maintained. Recent genetic studies have revealed an enormous diversity of bacteria as well as the spatial distribution of Bacteria, Archaea and Eukarya. These findings, together with emerging insights into the intimate interactions between these diverse populations, have contributed substantially to our understanding of the origins, environmental impacts, and biosignatures of photosynthetic microbial mats. The biosignatures (preservable cells, sedimentary fabrics, organic compounds, minerals, stable isotope patterns, etc.) potentially can serve as indicators of past life on early Earth. They also can inform our search for evidence of any life on Mars. Mars exploration has revealed evidence of evaporite deposits and thermal spring deposits; similar deposits on Earth once hosted ancient microbial mat ecosystems.

  19. The space microwave interferometer and the search for cosmic background gravitational wave radiation

    NASA Technical Reports Server (NTRS)

    Anderson, Allen Joel

    1989-01-01

    Present and planned investigations which use interplanetary spacecraft for gravitational wave searches are severely limited in their detection capability. This limitation has to do both with the Earth-based tracking procedures used and with the configuration of the experiments themselves. It is suggested that a much improved experiment can now be made using a multiarm interferometer designed with current operating elements. An important source of gravitational wave radiation, the cosmic background, may well be within reach of detection with these procedures. It is proposed to make a number of experimental steps that can now be carried out using TDRSS spacecraft and would conclude in the establishment of an operating multiarm microwave interferometer. This interferometer is projected to have a sensitivity to cosmic background gravitational wave radiation with an energy of less than 10(exp -4) cosmic closure density and to periodic waves generating spatial strain approaching 10(exp -19) in the range 0.1 to 0.001 Hz.

  20. Searching for Bio-Precursors and Complex Organic Molecules in Space using the GBT

    NASA Technical Reports Server (NTRS)

    Cordiner, M.; Charnley, S.; Kisiel, Z.

    2012-01-01

    Using the latest microwave receiver technology, large organic molecules with abundances as low as approx. 10(exp -11) times that of molecular hydrogen are detectable in cold interstellar clouds via their rotational emission line spectra. We report new observations to search for complex molecules, including molecules of possible pre-biotic importance, using the newly-commissioned Kband focal plane array (KFPA) of the NRAO Robert C. Byrd Green Bank Telescope. Spectra are presented of the dense molecular cloud TMC-1, showing strict upper limits on the level of emission from nitrogen-bearing rings pyrimidine, quinoline and iso-quinoline, carbon-chain oxides C60, C70, HC60 and HC70, and the carbon-chain anion C4H-. The typical RMS brightness temperature noise levels we achieved are approx. 1 mK at around 20 GHz.

  1. Passive solar space heating and cooling. (Latest citations from the NTIS Bibliographic database). NewSearch

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning the passive use of solar energy for space heating and cooling in buildings, houses, and homes. Citations discuss the design, performance, models, and economic analysis of heating and cooling systems. Topics include solar architecture, energy consumption analysis, energy conservation, and heat recovery. Also included are thermal comfort, quality of life, and housing for the elderly. (Contains a minimum of 209 citations and includes a subject term index and title list.)

  2. Robots for hazardous duties: Military, space, and nuclear facility applications. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1993-09-01

    The bibliography contains citations concerning the design and application of robots used in place of humans where the environment could be hazardous. Military applications include autonomous land vehicles, robotic howitzers, and battlefield support operations. Space operations include docking, maintenance, mission support, and intra-vehicular and extra-vehicular activities. Nuclear applications include operations within the containment vessel, radioactive waste operations, fueling operations, and plant security. Many of the articles reference control techniques and the use of expert systems in robotic operations. Applications involving industrial manufacturing, walking robots, and robot welding are cited in other published searches in this series. (Contains a minimum of 183 citations and includes a subject term index and title list.)

  3. Reducing the neural search space for hominid cognition: what distinguishes human and great ape brains from those of small apes?

    PubMed

    Butler, David; Suddendorf, Thomas

    2014-06-01

    Differences in the psychological capacities of closely related species are likely due to differences in their brains. Here, we review neuroanatomical comparisons between hominids (i.e., great apes and humans) and their closest living relatives, the hylobatids (i.e., small apes). We report the differences in quantitative, as well as qualitative, neural characteristics on the basis of 19 comparative studies that each included representatives of all hominid genera and at least one genus of hylobatid. The current data are patchy, based on a small number of hylobatids and few neuroanatomical features. Yet a systematic interspecies comparison could help reduce the neuroanatomical search space for the neural correlates underlying psychological abilities restricted to hominids. We illustrate the potential power of this approach by discussing the neural features of visual self-recognition.

  4. Ab initio materials design using conformational space annealing and its application to searching for direct band gap silicon crystals

    NASA Astrophysics Data System (ADS)

    Lee, In-Ho; Oh, Young Jun; Kim, Sunghyun; Lee, Jooyoung; Chang, K. J.

    2016-06-01

    Lately, the so-called inverse method of materials design has drawn much attention, where specific material properties are initially assigned and target materials are subsequently searched for. Although this method has been successful for some problems, the success of designing complex crystal structures containing many atoms is often limited by the efficiency of the search method utilized. Here we combine the global optimization method of conformational space annealing (CSA) with first-principles quantum calculations and report a new scheme named AMADEUS (Ab initio MAterials DEsign Using cSa). We demonstrate the utility of AMADEUS through the discovery of direct band gap Si crystals. The newly-designed direct gap Si allotropes show excellent optical properties and the spectroscopic limited maximum efficiencies comparable to those of best-known non-silicon photovoltaic materials. Our scheme not only provides a new perspective for the inverse problem of materials design but also may serve as a new tool for the computational design of a wide range of materials.

  5. Looking for Giant Earths in the HD 209458 System: A Search for Transits in MOST Space-based Photometry

    NASA Astrophysics Data System (ADS)

    Croll, Bryce; Matthews, Jaymie M.; Rowe, Jason F.; Kuschnig, Rainer; Walker, Andrew; Gladman, Brett; Sasselov, Dimitar; Cameron, Chris; Walker, Gordon A. H.; Lin, Douglas N. C.; Guenther, David B.; Moffat, Anthony F. J.; Rucinski, Slavek M.; Weiss, Werner W.

    2007-04-01

    We have made a comprehensive transit search for exoplanets down to about 2 Earth radii in the HD 209458 system, based on nearly uninterrupted broadband optical photometry obtained with the MOST (Microvariability and Oscillations of Stars) satellite, spanning 14 days in 2004 and 44 days in 2005. We have searched these data for limb-darkened transits at periods other than that of the known giant planet, from about 0.5 days to 2 weeks. Monte Carlo statistical tests of the data with synthetic transits inserted allow us to rule out additional close-in exoplanets with sizes ranging from about 0.20-0.36 RJ (Jupiter radii), or 2.2-4.0 R⊕ (Earth radii) on orbits whose planes are near that of HD 209458b. These null results constrain theories that invoke lower mass planets in orbits similar to HD 209458b to explain its anomalously large radius, and those that predict ``hot Earths'' due to the inward migration of HD 209458b. Based on data from the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon, Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna.

  6. OBJECTIVE REDUCTION OF THE SPACE-TIME DOMAIN DIMENSIONALITY FOR EVALUATING MODEL PERFORMANCE

    EPA Science Inventory

    In the United States, photochemical air quality models are the principal tools used by governmental agencies to develop emission reduction strategies aimed at achieving National Ambient Air Quality Standards (NAAQS). Before they can be applied with confidence in a regulatory sett...

  7. Hamiltonian reductions of the one-dimensional Vlasov equation using phase-space moments

    NASA Astrophysics Data System (ADS)

    Chandre, C.; Perin, M.

    2016-03-01

    We consider Hamiltonian closures of the Vlasov equation using the phase-space moments of the distribution function. We provide some conditions on the closures imposed by the Jacobi identity. We completely solve some families of examples. As a result, we show that imposing that the resulting reduced system preserves the Hamiltonian character of the parent model shapes its phase space by creating a set of Casimir invariants as a direct consequence of the Jacobi identity. We exhibit three main families of Hamiltonian models with two, three, and four degrees of freedom aiming at modeling the complexity of the bunch of particles in the Vlasov dynamics.

  8. Pre-Launch Risk Reduction Activities Conducted at KSC for the International Space Station

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, Paul

    2011-01-01

    In the development of any large scale space-based multi-piece assembly effort, planning must include provisions for testing and verification; not only of the individual pieces but also of the pieces together. Without such testing on the ground, the risk to cost, schedule and technical performance increases substantially. This paper will review the efforts undertaken by the International Space Station (ISS), including the International Partners, during the pre-launch phase, primarily at KSC, to reduce the risks associated with the on-orbit assembly and operation of the ISS.

  9. Space Shuttle main engine OPAD: The search for a hardware enhanced plume

    NASA Technical Reports Server (NTRS)

    Powers, W. T.; Cooper, A. E.; Wallace, Tim L.; Buntine, W. L.; Whitaker, K. W.

    1993-01-01

    The process of applying spectroscopy to the Space Shuttle Main Engine (SSME) for plume diagnostics, as it exists today, originated at Marshall Space Flight Center in Huntsville, Alabama, and its implementation was assured largely through the efforts of Sverdrup AEDC, in Tullahoma, Tennessee. This team continues to lead and guide efforts in the plume diagnostics arena. The process, Optical Plume Anomaly Detection (OPAD), formed the basis for various activities in the development of ground-based systems as well as the development of in-flight plume spectroscopy. OPAD currently provides and will continue to provide valuable information relative to future systems definitions, instrumentation development, code validation, and data diagnostic processing. OPAD is based on the detection of anomalous atomic and molecular species in the SSME plume using two complete, stand-alone optical spectrometers. To-date OPAD has acquired data on 44 test firings of the SSME at the Technology Test Bed (TTB) at MSFC. The purpose of this paper will be to provide an introduction to the OPAD system by discussing the process of obtaining data as well as the methods of examining and interpreting the data. It will encompass such issues as selection of instrumentation correlation of data to nominal engine operation, investigation of SSME component erosion via OPAD spectral data, necessity and benefits of plume seeding, application of artificial intelligence (AI) techniques to data analysis, and the present status of efforts to quantify specie erosion utilizing standard plume and chemistry codes as well as radiative models currently under development.

  10. NASA Space Science and a Search for Ram-Pressure Stripping in the Hydra I Cluster

    NASA Technical Reports Server (NTRS)

    Brown, Beth

    2005-01-01

    The NASA Goddard Space Flight Center's Sciences and Exploration Directorate seeks to expand scientific knowledge through observational and theoretical research in the study of the Earth-Sun system, the solar system and the origins of life, and the birth and evolution of the universe. This talk will discuss some of the cutting-edge space science research being conducted at Goddard. In addition, I will discuss my research on ram-pressure stripping in cluster elliptical galaxies. Ram-pressure stripping is a method by which hot interstellar gas can be removed from a galaxy moving through a group or cluster of galaxies. Indirect evidence of ram-pressure stripping includes lowered X-ray brightness in a galaxy due to less X-ray emitting gas remaining in the galaxy. Here we present the initial results of our program to determine whether cluster elliptical galaxies have lower hot gas masses than their counterparts in less rich environments. This test requires the use of the high-resolution imaging of the Chandra Observatory and we present our analysis of the galaxies in the nearby cluster Hydra I.

  11. In Pursuit of New Worlds: Searches for and Studies of Transiting Exoplanets from Three Space-Based Observatories

    NASA Astrophysics Data System (ADS)

    Ballard, Sarah Ashley

    2012-01-01

    This thesis presents studies of transiting exoplanets using observations gathered in large part from space, with the NASA EPOXI Mission, the Spitzer Space Telescope, and the Kepler Mission. The first part of this thesis describes searches for additional transiting planets in known exoplanet systems, using time series photometry gathered as part of the NASA EPOXI Mission. Using the EPOXI light curves spanning weeks for each star, we searched six exoplanetary systems for signatures of additional transiting planets. These six systems include five hosts to hot Jupiters: HAT-P-4, TrES-3, TrES-2, WASP-3, and HAT-P-7, and one host to a hot Neptune: GJ 436. We place upper limits on the presence of additional transiting planets in the super-Earth radius range for GJ 436 in Chapter 2, and in the Neptune-to-Saturn radius range for the other five systems in Chapter 4. Chapter 3 details a search for additional transits of a hypothesized planet smaller than the Earth, whose presence was suggested by the EPOXI observations of GJ 436. In that study, we demonstrate the sensitivity of Warm Spitzer observations to transits of a sub-Earth-sized planet. The fifth chapter details the characterization and validation of the Kepler-19 system, which hosts a transiting 2.2 R⊕ planet, Kepler-19b. We demonstrate the planetary nature of the transit signal with an analysis that combines information from high-resolution spectroscopy, the shape of the transit light curve, adaptive optics imaging, and near-infrared transits of the planet. The sinusoidal variation in the transit times of Kepler-19b indicates the presence of an additional perturbing body, and comprises the first definitive detection of a planet using the transit timing variation method. While we cannot uniquely determine the mass and orbital period of Kepler-19c, we establish that its mass must be less than 6 times the mass of Jupiter. The sixth chapter presents evidence for the validation of a 2.0 R ⊕ planet residing in the

  12. INDOOR RADON REDUCTION IN CRAWL-SPACE HOUSES: A REVIEW OF ALTERNATIVE APPROACHES

    EPA Science Inventory

    An analysis has been completed of the performance, mechanisms, and costs of alternative technologies for preventing radon entry into the living areas of houses having crawl-space foundations. Sub-membrane depressurization (SMD) is consistently the most effective technique, often ...

  13. Antimatter and Dark Matter Search in Space: BESS-Polar Results

    NASA Technical Reports Server (NTRS)

    Mitchell, John W.; Yamamoto, Akira

    2009-01-01

    The apex of the Balloon-borne Experiment with a Superconducting Spectrometer program was reached with the Antarctic flight of BESS-Polar II, during the 2007-2008 Austral Summer, that obtained 24.5 days of data on over 4.7 billion cosmic-ray events. The US-Japan BESS Collaboration uses elementary particle measurements to study the early Universe and provides fundamental data on the spectra of light cosmic-ray elements and isotopes. BESS measures the energy spectra of cosmic-ray antiprotons to investigate signatures of possible exotic sources, such as dark-matter candidates, and searches for heavier anti-nuclei that might reach Earth from antimatter domains formed during symmetry breaking processes in the early Universe. Since 1993, BESS has carried out eleven high-latitude balloon flights, two of long duration, that together have defined the study of antiprotons below about 4 GeV, provided standard references for light element and isotope spectra, and set the most sensitive limits on the existence of anti-deuterons and anti-helium, The BESS-Polar II flight took place at Solar Minimum, when the sensitivity of the low-energy antiproton measurements to a primary source is greatest. The rich BESS-Polar II dataset more than doubles the combined data from all earlier BESS flights and has 10-20 times the statistics of BESS data from the previous Solar Minimum. Here, we summarize the scientific results of BESS program, focusing on the results obtained using data from the long-duration flights of BESS-Polar I (2004) and BESS-Polar II.

  14. Oases{emdash}A space mission to search for habitable planets of other stars

    SciTech Connect

    Angel, R.; Woolf, N.; Leger, A.

    1996-03-01

    We do not yet know if nearby sun-like stars have planets resembling the solar system. In the past, telescopes have not had the power to resolve weak planet emission next to a bright star{emdash}it is as if from a thousand miles away one tried to see a glow worm next to a searchlight. But a telescope in space could now be built by NASA that could not only see Earth-like planets if they are there, but check if they have abundant water or even an atmosphere with oxygen, produced on Earth by primitive life. The name we have given to such a mission is OASES{emdash}Outpost for the Analysis and Spectroscopy of Exo-planetary Systems. {copyright} {ital 1996 American Institute of Physics.}

  15. Pattern drilling exploration: Optimum pattern types and hole spacings when searching for elliptical shaped targets

    USGS Publications Warehouse

    Drew, L.J.

    1979-01-01

    In this study the selection of the optimum type of drilling pattern to be used when exploring for elliptical shaped targets is examined. The rhombic pattern is optimal when the targets are known to have a preferred orientation. Situations can also be found where a rectangular pattern is as efficient as the rhombic pattern. A triangular or square drilling pattern should be used when the orientations of the targets are unknown. The way in which the optimum hole spacing varies as a function of (1) the cost of drilling, (2) the value of the targets, (3) the shape of the targets, (4) the target occurrence probabilities was determined for several examples. Bayes' rule was used to show how target occurrence probabilities can be revised within a multistage pattern drilling scheme. ?? 1979 Plenum Publishing Corporation.

  16. A search for free quarks in the micro gravity environment of the International Space Station

    NASA Astrophysics Data System (ADS)

    Hudspeth, Paul; Klingler, Robert

    2000-01-01

    Authors propose using the zero-gravity environment of the International Space Station to gather evidence for or against quark particles existing as free radicals in nature. Their proposed method is based on a micro gravity version of 1923 Nobel Prize winner Robert Millikan's oil drop method of determining the fundamental charge on a single electron. Although Millikan's original experiments were carried out in 1909, and showed that all electrical charge exists as whole integer multiples of the fundamental electron unit, Millikan observed and recorded in lab notebooks, the existence of a tiny oil droplet which had a +1/3 partial charge, which he dismissed as an error. Not until the 1960's did quark theory and Particle Accelerators show that protons and neutrons were actually composed of smaller particles called ``quarks'' which indeed bear unique fractional charges. Authors propose observing one millimeter or larger grounded metal spheres suspended in micro gravity between oppositely charged metal plates for telltale motion behavior caused by the fractional charge unique to the quark particle. The ability afforded by micro gravity to use test objects of much greater mass than that of oil droplets equates to being able to perform 100 million Millikan tests in a single run -more by far than the sum total of all the tests ever performed on earth. The significant breakthroughs in terms of deep space propulsion and energy production, hinging on the question of free quark existence, are noted. Preliminary results of basic experimental apparatus construction and testing aboard NASA KC-135 zero-gravity flights are reported, along with recommendations for future experiments. Authors note ideal nature of the experiment in terms of possible student interaction with astronauts and real-time exhibition of testing via the Internet. .

  17. The Sharing Experimental Animal Resources, Coordinating Holdings (SEARCH) Framework: Encouraging Reduction, Replacement, and Refinement in Animal Research

    PubMed Central

    Morrissey, Bethny; Blyth, Karen; Carter, Phil; Chelala, Claude; Jones, Louise; Holen, Ingunn; Speirs, Valerie

    2017-01-01

    While significant medical breakthroughs have been achieved through using animal models, our experience shows that often there is surplus material remaining that is frequently never revisited but could be put to good use by other scientists. Recognising that most scientists are willing to share this material on a collaborative basis, it makes economic, ethical, and academic sense to explore the option to utilise this precious resource before generating new/additional animal models and associated samples. To bring together those requiring animal tissue and those holding this type of archival material, we have devised a framework called Sharing Experimental Animal Resources, Coordinating Holdings (SEARCH) with the aim of making remaining material derived from animal studies in biomedical research more visible and accessible to the scientific community. We encourage journals, funding bodies, and scientists to unite in promoting a new way of approaching animal research by adopting the SEARCH framework. PMID:28081116

  18. The Sharing Experimental Animal Resources, Coordinating Holdings (SEARCH) Framework: Encouraging Reduction, Replacement, and Refinement in Animal Research.

    PubMed

    Morrissey, Bethny; Blyth, Karen; Carter, Phil; Chelala, Claude; Jones, Louise; Holen, Ingunn; Speirs, Valerie

    2017-01-01

    While significant medical breakthroughs have been achieved through using animal models, our experience shows that often there is surplus material remaining that is frequently never revisited but could be put to good use by other scientists. Recognising that most scientists are willing to share this material on a collaborative basis, it makes economic, ethical, and academic sense to explore the option to utilise this precious resource before generating new/additional animal models and associated samples. To bring together those requiring animal tissue and those holding this type of archival material, we have devised a framework called Sharing Experimental Animal Resources, Coordinating Holdings (SEARCH) with the aim of making remaining material derived from animal studies in biomedical research more visible and accessible to the scientific community. We encourage journals, funding bodies, and scientists to unite in promoting a new way of approaching animal research by adopting the SEARCH framework.

  19. Investigation of the equality constraint effect on the reduction of the rotational ambiguity in three-component system using a novel grid search method.

    PubMed

    Beyramysoltan, Samira; Rajkó, Róbert; Abdollahi, Hamid

    2013-08-12

    The obtained results by soft modeling multivariate curve resolution methods often are not unique and are questionable because of rotational ambiguity. It means a range of feasible solutions equally fit experimental data and fulfill the constraints. Regarding to chemometric literature, a survey of useful constraints for the reduction of the rotational ambiguity is a big challenge for chemometrician. It is worth to study the effects of applying constraints on the reduction of rotational ambiguity, since it can help us to choose the useful constraints in order to impose in multivariate curve resolution methods for analyzing data sets. In this work, we have investigated the effect of equality constraint on decreasing of the rotational ambiguity. For calculation of all feasible solutions corresponding with known spectrum, a novel systematic grid search method based on Species-based Particle Swarm Optimization is proposed in a three-component system.

  20. Metrics in the space of orbits and their application to searching for celestial objects of common origin

    NASA Astrophysics Data System (ADS)

    Kholshevnikov, K. V.; Kokhirova, G. I.; Babadzhanov, P. B.; Khamroev, U. H.

    2016-10-01

    Finding a common origin for various celestial bodies, especially the relations between meteoroid streams, comets and asteroids (possibly extinct comets), remains one of the important problems in Solar system astronomy. Different criteria, starting with one by Southworth and Hawkins, have been used for this purpose. Ideally, they must represent some kind of metric in a five-dimensional space of orbits. Unfortunately, they are not ideal. The majority of the criteria have been examined by us. It turns out that they all represent pseudometrics for which the triangle axiom is not fulfilled. Besides this, they are inapplicable if at least one of the orbits is circular. We propose metrics free of all the aforementioned drawbacks. In addition, the metric properties of three factor-spaces, where orbits are identified irrespective of the values of node longitudes, pericentre arguments or both, are examined. The results are applied to the problem of searching for minor bodies of the Solar system with a common origin. The relationship between comet 96P/Machholz 1 and asteroid 2003EH1, as well as that between comet 2P/Encke and asteroid 2004TG10, has been proved. Using all criteria considered and the new metrics leads to practically identical results. This is explained by the fact that only close and essentially non-circular orbits were analysed. Besides this, the measure of orbit triples for which the triangle axiom failed is likely small, though this problem has not been examined yet.

  1. Firms navigating through innovation spaces: a conceptualization of how firms search and perceive technological, market and productive opportunities globally.

    PubMed

    McKelvey, Maureen

    2016-01-01

    The main contribution of this paper is a theory-based conceptual framework of innovation spaces, and how firms must navigate through them to innovate. The concept of innovation systems - at the regional, sectoral and national levels - have been highly influential. Previous literature developing the concept of innovation systems has stressed the importance of institutions, networks and knowledge bases at the regional, sectoral and national levels. This paper primarily draws upon an evolutionary and Schumpeterian economics perspective, in the following three senses. The conceptualization of 'innnovation spaces' focuses upon how and why firm search for innovations is influenced the opportunities within certain geographical contexts. This means that the firm create opportunities and can span different context, but they are influence by the context in term of the access, flow and co-evolution of ideas, resources, technology, people and knowledge, which help stimulate business innovation in terms of products, process and services. The paper concludes with an agenda for future research and especially the need to focus on globalization as a process of intensifying linkages across the globe.

  2. Dynamic Control System Performance during Commissioning of the Space Technology 7-Disturbance Reduction System Experiment of LISA Pathfinder

    NASA Technical Reports Server (NTRS)

    Hsu, Oscar; Maghami, Peiman; O’Donnell, James R., Jr.; Ziemer, John; Romero-Wolf, Andrew

    2017-01-01

    The Space Technology-7 Disturbance Reduction System (DRS) launched aboard the European Space Agencys LISA Pathfinder spacecraft on December 3, 2015, after more than a decade in development. DRS consists of three prima-ry components: an Integrated Avionics Unit (IAU), Colloidal MicroNewton Thrusters, and Dynamic Control System (DCS) algorithms implemented on the IAU. During the portions of the mission in which the DRS was under control, the DCS was responsible for controlling the spacecraft and the free-floating test masses that were part of the LISA Test Package. The commissioning period was originally divided into two periods: before propulsion separation and after pro-pulsion separation. A recommissioning period was added after an anomaly oc-curred in the thruster system. The paper will describe the activities used to com-mission DRS, present results from the commissioning of the DCS and the re-commissioning activities performed after the thruster anomaly.

  3. Dynamic Control System Performance during Commissioning of the Space Technology 7-Disturbance Reduction System Experiment of LISA Pathfinder

    NASA Technical Reports Server (NTRS)

    Hsu, Oscar; Maghami, Peiman; O’Donnell, James R., Jr.; Ziemer, John; Romero-Wolf, Andrew

    2017-01-01

    The Space Technology-7 Disturbance Reduction System (DRS) launched aboard the European Space Agency's LISA Pathfinder spacecraft on December 3, 2015, after more than a decade in development. DRS consists of three primary components: an Integrated Avionics Unit (IAU), Colloidal MicroNewton Thrusters, and Dynamic Control System (DCS) algorithms implemented on the IAU. During the portions of the mission in which the DRS was under control, the DCS was responsible for controlling the spacecraft and the free-floating test masses that were part of the LISA Test Package. The commissioning period was originally divided into two periods: before propulsion separation and after propulsion separation. A recommissioning period was added after an anomaly occurred in the thruster system. The paper will describe the activities used to commission DRS, present results from the commissioning of the DCS and the recommissioning activities per-formed after the thruster anomaly.

  4. Great SEP events and space weather, 1. Experience of automatically search of event beginning; probabilities of false and missed alerts

    NASA Astrophysics Data System (ADS)

    Dorman, L.; Pustil Nik, L.; Sternlieb, A.; Zukerman, I.

    It is well known that in periods of great SEP fluxes of energetic particles can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead: according to NOAA Space Weather Scales are dangerous Solar Radiation Storms S5-extreme (flux level of particles with energy > 10 MeV more than 10^5), S4-severe (flux more than 10^4) and S3-strong (flux more than 10^3). In these periods is necessary to switch off some part of electronics for few hours to protect computer memories. These periods are also dangerous for astronauts on space-ships, and passengers and crew in commercial jets (especially during S5 storms). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (few GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coefficient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into solar wind) than main part of smaller energy particles caused dangerous situation for electronics (about 30-60 minutes later). We describe here principles and experience of automatically working of program "FEP- Search". The positive result which shows the exact beginning of FEP event on the Emilio Segre' Observatory (2025 m above sea level, Rc=10.8 GV), is determined now automatically by simultaneously increasing on 2.5 St. Dev. in two sections of neutron supermonitor. The next 1min data the program "FEP-Search" uses for- checking that the observed increase reflects the beginning of real great FEP or not. If yes, automatically starts to work on line the programs "FEP-Research". We determine also the probabilities of false and missed alerts. The work of NM on Mt. Hermo n is supported by Israel (Tel Aviv University and ISA) - Italian (UNIRoma- Tre and IFSI-CNR) collaboration. This research is

  5. Reflected Sunlight Reduction and Characterization for a Deep-Space Optical Receiver Antenna (DSORA)

    NASA Technical Reports Server (NTRS)

    Clymer, B. D.

    1990-01-01

    A baffle system for the elimination of first-order specular and diffuse reflection of sunlight from the sunshade of a deep-space optical receiver telescope is presented. This baffle system consists of rings of 0.5cm blades spaced 2.5 cm apart on the walls of GO hexagonal sunshade tubes that combine to form the telescope sunshade. The shadow cast by the blades, walls, and rims of the tubes prevent all first-order reflections of direct sunlight from reaching the primary mirror of the telescope. A reflection model of the sunshade without baffles is also presented for comparison. Since manufacturers of absorbing surfaces do not measure data near grazing incidence, the reflection properties at anticipated angles of incidence must be characterized. A description of reflection from matte surfaces in term of bidirectional reflection distribution function (BRDF) is presented along with a discussion of measuring BRDF near grazing incidence.

  6. Reduction of spermatogonia and testosterone in rat testes flown on Space Lab-3

    NASA Technical Reports Server (NTRS)

    Philpott, Delbert E.; Stevenson, J.; Black, S.; Sapp, W.; Williams, C.

    1986-01-01

    The effects of space flight on rat testes were investigated. The weight, spermatogonial cell count, and testosterone levels in six rats flown on Space Lab-3 were measured. It is observed that compared to ground control rats the average weight loss was 7.1 percent and the spermatogonial cell count decreased by 7.5 percent. The data reveal that the testosterone level for large control rats was 9.13 ng/ml and 0.31 ng/ml for flight rats; and 2.54 ng/ml and 0.233 ng/ml for smaller control and flight rats, respectively. It is noted that spermatogenesis and testosterone production are reduced during spaceflight.

  7. Development of a Wake Vortex Spacing System for Airport Capacity Enhancement and Delay Reduction

    NASA Technical Reports Server (NTRS)

    Hinton, David A.; OConnor, Cornelius J.

    2000-01-01

    The Terminal Area Productivity project has developed the technologies required (weather measurement, wake prediction, and wake measurement) to determine the aircraft spacing needed to prevent wake vortex encounters in various weather conditions. The system performs weather measurements, predicts bounds on wake vortex behavior in those conditions, derives safe wake spacing criteria, and validates the wake predictions with wake vortex measurements. System performance to date indicates that the potential runway arrival rate increase with Aircraft VOrtex Spacing System (AVOSS), considering common path effects and ATC delivery variance, is 5% to 12% depending on the ratio of large and heavy aircraft. The concept demonstration system, using early generation algorithms and minimal optimization, is performing the wake predictions with adequate robustness such that only 4 hard exceedances have been observed in 1235 wake validation cases. This performance demonstrates the feasibility of predicting wake behavior bounds with multiple uncertainties present, including the unknown aircraft weight and speed, weather persistence between the wake prediction and the observations, and the location of the weather sensors several kilometers from the approach location. A concept for the use of the AVOSS system for parallel runway operations has been suggested, and an initial study at the JFK International Airport suggests that a simplified AVOSS system can be successfully operated using only a single lidar as both the weather sensor and the wake validation instrument. Such a selfcontained AVOSS would be suitable for wake separation close to the airport, as is required for parallel approach concepts such as SOIA.

  8. Exploring the space of histidine containing dipeptides in search of novel efficient RCS sequestering agents.

    PubMed

    Vistoli, Giulio; De Maddis, Danilo; Straniero, Valentina; Pedretti, Alessandro; Pallavicini, Marco; Valoti, Ermanno; Carini, Marina; Testa, Bernard; Aldini, Giancarlo

    2013-08-01

    The study reports a set of forty proteinogenic histidine-containing dipeptides as potential carbonyl quenchers. The peptides were chosen to cover as exhaustively as possible the accessible chemical space, and their quenching activities toward 4-hydroxy-2-nonenal (HNE) and pyridoxal were evaluated by HPLC analyses. The peptides were capped at the C-terminus as methyl esters or amides to favor their resistance to proteolysis and diastereoisomeric pairs were considered to reveal the influence of configuration on quenching. On average, the examined dipeptides are less active than the parent compound carnosine (βAla + His) thus emphasizing the unfavorable effect of the shortening of the βAla residue as confirmed by the control dipeptide Gly-His. Nevertheless, some peptides show promising activities toward HNE combined with a remarkable selectivity. The results emphasize the beneficial role of aromatic and positively charged residues, while negatively charged and H-bonding side chains show a detrimental effect on quenching. As a trend, ester derivatives are slightly more active than amides while heterochiral peptides are more active than their homochiral diastereoisomer. Overall, the results reveal that quenching activity strongly depends on conformational effects and vicinal residues (as evidenced by the reported QSAR analysis), offering insightful clues for the design of improved carbonyl quenchers and to rationalize the specific reactivity of histidine residues within proteins.

  9. Large space structure model reduction and control system design based upon actuator and sensor influence functions

    NASA Technical Reports Server (NTRS)

    Yam, Y.; Lang, J. H.; Johnson, T. L.; Shih, S.; Staelin, D. H.

    1983-01-01

    A model reduction procedure based on aggregation with respect to sensor and actuator influences rather than modes is presented for large systems of coupled second-order differential equations. Perturbation expressions which can predict the effects of spillover on both the aggregated and residual states are derived. These expressions lead to the development of control system design constraints which are sufficient to guarantee, to within the validity of the perturbations, that the residual states are not destabilized by control systems designed from the reduced model. A numerical example is provided to illustrate the application of the aggregation and control system design method.

  10. AsteroidFinder - The Space-Borne Telescope to Search for NEO Asteroids

    NASA Astrophysics Data System (ADS)

    Hartl, M.; Mosebach, H.; Schubert, J.; Michaelis, H.; Mottola, S.; Kührt, E.; Schindler, K.

    2010-10-01

    This paper presents the mission profile as well as the optical configuration of the space-borne AsteroidFinder telescope. Its main objective is to retrieve asteroids with orbits interior to the earth's orbit. The instrument requires high sensitivity to detect asteroids with a limiting magnitude of equal or larger than 18.5mag (V-Band) and astrometric accuracy of 1arcsec (1σ). This requires a telescope aperture greater than 400cm2, high image stability, detector with high quantum efficiency (peak > 90%) and very low noise, which is only limited by zodiacal background. The telescope will observe the sky between 30° and 60° in solar elongation. The telescope optics is based on a Cook type TMA. An effective 2°×2° field of view (FOV) is achieved by a fast F/3.4 telescope with near diffraction-limited performance. The absence of centre obscuration or spiders in combination with an accessible intermediate field plane and exit pupil allow for efficient stray light mitigation. Design drivers for the telescope are the required point spread function (PSF) values, an extremely efficient stray light suppression (due to the magnitude requirement mentioned above), the detector performance, and the overall optical and mechanical stability for all orientations of the satellite. To accommodate the passive thermal stabilization scheme and the necessary structural stability, the materials selection for the telescope main structure and the mirrors are of vital importance. A focal plane with four EMCCD detectors is envisaged. The EMCCD technology features shorter integration times, which is in favor regarding the pointing performance of the satellite. The launch of the mission is foreseen for the year 2013 with a subsequent mission lifetime of at least 1 year.

  11. Hubble Space Telescope: cost reduction by re-engineering telemetry processing and archiving

    NASA Astrophysics Data System (ADS)

    Miebach, Manfred P.

    1998-05-01

    The Hubble Space Telescope (HST), the first of NASA's Great Observatories, was launched on April 24, 1990. The HST was designed for a minimum fifteen-year mission with on-orbit servicing by the Space Shuttle System planned at approximately three-year intervals. Major changes to the HST ground system are planned to be in place for the third servicing mission in December 1999. The primary objectives of the ground system reengineering effort, a project called 'vision December 1999. The primary objectives of the ground system re-engineering effort, a project called 'vision 2000 control center systems (CCS)', are to reduce both development and operating costs significantly for the remaining years of HST's lifetime. Development costs will be reduced by providing a modern hardware and software architecture and utilizing commercial of f the shelf (COTS) products wherever possible. Operating costs will be reduced by eliminating redundant legacy systems and processes and by providing an integrated ground system geared toward autonomous operation. Part of CCS is a Space Telescope Engineering Data Store, the design of which is based on current Data Warehouse technology. The purpose of this data store is to provide a common data source of telemetry data for all HST subsystems. This data store will become the engineering data archive and will include a queryable database for the user to analyze HST telemetry. The access to the engineering data in the Data Warehouse is platform- independent from an office environment using commercial standards. Latest internet technology is used to reach the HST engineering community. A WEB-based user interface allows easy access to the data archives. This paper will provide a high level overview of the CCS system and will illustrate some of the CCS telemetry capabilities. Samples of CCS user interface pages will be given. Vision 2000 is an ambitious project, but one that is well under way. It will allow the HST program to realize reduced

  12. Space Radiation Cancer Risk Projections for Exploration Missions: Uncertainty Reduction and Mitigation

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis; Badhwar, Gautam; Saganti, Premkumar; Schimmerling, Walter; Wilson, John; Peterson, Leif; Dicello, John

    2002-01-01

    In this paper we discuss expected lifetime excess cancer risks for astronauts returning from exploration class missions. For the first time we make a quantitative assessment of uncertainties in cancer risk projections for space radiation exposures. Late effects from the high charge and energy (HZE) ions present in the galactic cosmic rays including cancer and the poorly understood risks to the central nervous system constitute the major risks. Methods used to project risk in low Earth orbit are seen as highly uncertain for projecting risks on exploration missions because of the limited radiobiology data available for estimating HZE ion risks. Cancer risk projections are described as a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Monte-Carlo sampling from subjective error distributions represents the lack of knowledge in each factor to quantify risk projection overall uncertainty. Cancer risk analysis is applied to several exploration mission scenarios. At solar minimum, the number of days in space where career risk of less than the limiting 3% excess cancer mortality can be assured at a 95% confidence level is found to be only of the order of 100 days.

  13. Autonomous image data reduction by analysis and interpretation. [for space missions

    NASA Technical Reports Server (NTRS)

    Eberlein, Susan; Yates, Gigi; Ritter, Niles

    1988-01-01

    Image data is a critical component of the scientific information acquired by space missions. Compression of image data is required due to the limited bandwidth of the data transmission channel and limited memory space on the acquisition vehicle. This need becomes more pressing when dealing with multispectral data where each pixel may comprise 300 or more bytes. An autonomous, real time, on-board image analysis system for an exploratory vehicle such as a Mars Rover is developed. The completed system will be capable of interpreting image data to produce reduced representations of the image, and of making decisions regarding the importance of data based on current scientific goals. Data from multiple sources, including stereo images, color images, and multispectral data, are fused into single image representations. Analysis techniques emphasize artificial neural networks. Clusters are described by their outlines and class values. These analysis and compression techniques are coupled with decision-making capacity for determining importance of each image region. Areas determined to be noise or uninteresting can be discarded in favor of more important areas. Thus limited resources for data storage and transmission are allocated to the most significant images.

  14. Strategy for the reduction of total integrated fluid logistics to the Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Gould, Marston J.; Shannon, David T., Jr.

    1993-01-01

    The use of an integrated environmental control and life support system (ECLSS) and secondary propulsion system (SRS) on the Space Station Freedom (SSF) has many potential advantages. Through the metabolism of food, the crew on-board the station will produce carbon dioxide as a waste gas and an excess of water in the form of urine and condensate. The processing of these waste fluids by the ECLSS could produce quantities of oxygen that would eliminate the need for cryogenic oxygen resupply and hydrogen, carbon dioxide, and/or methane that could be used with the addition of a resistojet system to provide a constant low thrust for station. This additional thrust would represent significant savings in required hydrazine resupply.

  15. A Hubble space telescope search for a sub-Earth-sized exoplanet in the GJ 436 system

    SciTech Connect

    Stevenson, Kevin B.; Bean, Jacob L.; Fabrycky, Daniel; Kreidberg, Laura

    2014-11-20

    The detection of small planets orbiting nearby stars is an important step toward the identification of Earth twins. In previous work using the Spitzer Space Telescope, we found evidence to support at least one sub-Earth-sized exoplanet orbiting the nearby mid-M dwarf star GJ 436. As a follow up, here we used the Hubble Space Telescope (HST) to investigate the existence of one of these candidate planets, UCF-1.01, by searching for two transit signals as it passed in front of its host star. Interpretation of the data hinges critically on correctly modeling and removing the Wide Field Camera 3 (WFC3) instrument systematics from the light curves. Building on previous HST work, we demonstrate that WFC3 analyses need to explore the use of a quadratic function to fit a visit-long time-dependent systematic. This is important for establishing absolute transit and eclipse depths in the white light curves of all transiting systems. The work presented here exemplifies this point by putatively detecting the primary transit of UCF-1.01 with the use of a linear trend. However, using a quadratic trend, we achieve a better fit to the white light curves and a reduced transit depth that is inconsistent with previous Spitzer measurements. Furthermore, quadratic trends with or without a transit model component produce comparable fits to the available data. Using extant WFC3 transit light curves for GJ 436b, we further validate the quadratic model component by achieving photon-limited model fit residuals and consistent transit depths over multiple epochs. We conclude that, when we fit for a quadratic trend, our new data contradict the prediction of a sub-Earth-sized planet orbiting GJ 436 with the size, period, and ephemeris posited from the Spitzer data by a margin of 3.1σ.

  16. Conformational Space and Stability of ETD Charge Reduction Products of Ubiquitin

    NASA Astrophysics Data System (ADS)

    Lermyte, Frederik; Łącki, Mateusz Krzysztof; Valkenborg, Dirk; Gambin, Anna; Sobott, Frank

    2017-01-01

    Owing to its versatility, electron transfer dissociation (ETD) has become one of the most commonly utilized fragmentation techniques in both native and non-native top-down mass spectrometry. However, several competing reactions—primarily different forms of charge reduction—occur under ETD conditions, as evidenced by the distorted isotope patterns usually observed. In this work, we analyze these isotope patterns to compare the stability of nondissociative electron transfer (ETnoD) products, specifically noncovalent c/ z fragment complexes, across a range of ubiquitin conformational states. Using ion mobility, we find that more extended states are more prone to fragment release. We obtain evidence that for a given charge state, populations of ubiquitin ions formed either directly by electrospray ionization or through collapse of more extended states upon charge reduction, span a similar range of collision cross-sections. Products of gas-phase collapse are, however, less stabilized towards unfolding than the native conformation, indicating that the ions retain a memory of previous conformational states. Furthermore, this collapse of charge-reduced ions is promoted if the ions are `preheated' using collisional activation, with possible implications for the kinetics of gas-phase compaction.

  17. Improved Multispectral Skin Detection and its Application to Search Space Reduction for Dismount Detection Based on Histograms of Oriented Gradients

    DTIC Science & Technology

    2010-03-01

    Conference Series, volume 6699 of Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series. August 2007. 12. Brand, Jason and John S. Mason...spectral.lib06. 16. Conaire, C. , N. E. Oconnor, E. Cooke, and A. F. Smeaton . “Multispectral Object Segmentation and Retrieval in Surveillance Video...lear.inrialpes.fr/pubs/2004/MSZ04. 44. Miller, John L. Principles of infrared technology: a practical guide to the state of the art. first edition, 1994. ISBN

  18. The Reduction and Treatment of Serious Mental Illness during Long Duration Space Mission.

    NASA Astrophysics Data System (ADS)

    Mardon, Austin; Nichol, Kenneth; Mardon, Catherine; Mardon, Austin

    It is well known in the history of terrestrial naval expeditions that members of long expeditions could and did suffered from serious mental illnesses. Depression and even psychosis could inflict crew members, and in serious cases this sometimes resulted in violence directed towards others or themselves. There was little that the medical practitioners of the time could do to alleviate these illnesses. Modern psychiatry operates within a paradigm of the normalcy of the modern western standard of living. When we place humans outside these normal experiences, we place them in vulnerable positions. For the foreseeable future, spaceflight will continue to result in extremely physically, mentally and spiritually arduous expeditions. As we start our journey towards Mars and beyond, the time humans will be in the isolation of space, and subjected to these extraordinary stresses, will increase. The recent incident where an American astronaut had a mental collapse and was criminally charged is indicative of this real possibility. One solution could be to have more pre-screening but this only goes so far, especially when the rigorous training and the actual mission might cause psychological problems that were never present before hand. Eastern and Western philosophies and religious systems can provide a framework to draw upon to strengthen the mental and spiritual psyche of the astronauts on a long duration expedition. Meditative techniques and prayer techniques, if within the belief system of the astronaut, might serve to prevent or ameliorate the severity of a mental collapse should it occur during a space mission. Many of the American astronauts that went to the Moon reported having intense emotional and spiritual reactions based on the intensity of their experiences. For several of these men, the courses of their lives were changed. What astronauts will face by going back to the Moon and further a field to Mars, will be dangerous and extremely mentally taxing. At the

  19. The millimeter wave spectrum of methyl cyanate: a laboratory study and astronomical search in space ⋆,⋆⋆

    PubMed Central

    Kolesniková, L.; Alonso, J. L.; Bermúdez, C.; Alonso, E. R.; Tercero, B.; Cernicharo, J.; Guillemin, J.-C.

    2016-01-01

    Aims The recent discovery of methyl isocyanate (CH3NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH3OCN) a potential molecule in the interstellar medium. The aim of this work is to fulfill the first requirement for its unequivocal identification in space, i.e. the availability of transition frequencies with high accuracy. Methods The room-temperature rotational spectrum of methyl cyanate was recorded in the millimeter wave domain from 130 to 350 GHz. All rotational transitions revealed A-E splitting owing to methyl internal rotation and were globally analyzed using the ERHAM program. Results The data set for the ground torsional state of methyl cyanate exceeds 700 transitions within J″ = 10 – 35 and Ka″=0−13 and newly derived spectroscopic constants reproduce the spectrum close to the experimental uncertainty. Spectral features of methyl cyanate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methyl cyanate are provided. PMID:27721514

  20. Identification of Predictive Cis-Regulatory Elements Using a Discriminative Objective Function and a Dynamic Search Space

    PubMed Central

    Karnik, Rahul; Beer, Michael A.

    2015-01-01

    The generation of genomic binding or accessibility data from massively parallel sequencing technologies such as ChIP-seq and DNase-seq continues to accelerate. Yet state-of-the-art computational approaches for the identification of DNA binding motifs often yield motifs of weak predictive power. Here we present a novel computational algorithm called MotifSpec, designed to find predictive motifs, in contrast to over-represented sequence elements. The key distinguishing feature of this algorithm is that it uses a dynamic search space and a learned threshold to find discriminative motifs in combination with the modeling of motifs using a full PWM (position weight matrix) rather than k-mer words or regular expressions. We demonstrate that our approach finds motifs corresponding to known binding specificities in several mammalian ChIP-seq datasets, and that our PWMs classify the ChIP-seq signals with accuracy comparable to, or marginally better than motifs from the best existing algorithms. In other datasets, our algorithm identifies novel motifs where other methods fail. Finally, we apply this algorithm to detect motifs from expression datasets in C. elegans using a dynamic expression similarity metric rather than fixed expression clusters, and find novel predictive motifs. PMID:26465884

  1. Dead space reduction by Kolobow's endotracheal tube does not justify the waiving of volume monitoring in small, ventilated lungs.

    PubMed

    Proquitté, Hans; Wendel, Rena; Roehr, Charles C; Wauer, Roland R; Schmalisch, Gerd

    2014-12-01

    In ventilated preterm infants the flow sensor contributes significantly to the total apparatus dead space, which may impair gas exchange. The aim of the study was to quantify to which extent a dead space reduced Kolobow tube (KB) without flow sensor improves the gas exchange compared with a conventional ventilator circuit with flow sensor [Babylog 8000 (BL)]. In a cross-over trial in 14 tracheotomized, surfactant-depleted (saline lavage) and mechanically ventilated newborn piglets (age <12 h; body weight 705-1200 g) BL and KB was applied alternately for 15 min and blood gases were recorded. The inner diameter of the endotracheal tube was 3.6 mm and the apparatus dead space of BL and KB including the endotracheal tube were 3.0 and 1.34 mL. Despite a 50 % apparatus dead space reduction with KB compared to BL statistically significant improvements were only observed for body weights <900 g. In this weight group median paCO2 was decreased by 5 mmHg (p < 0.01), whereas the improvement decreased with decreasing baseline paCO2. Furthermore, median paO2 was increased by 4 mmHg (p < 0.05) and O2 saturation was increased by 2.5 % (p < 0.05). No significant changes were seen in the circulatory parameters. In very small, ventilated lungs the use of KB improved the gas exchange; however, the improvement was moderate and does not justify the waiving of volume monitoring.

  2. On State-Space Reduction in Multi-Strain Pathogen Models, with an Application to Antigenic Drift in Influenza A

    PubMed Central

    Kryazhimskiy, Sergey; Dieckmann, Ulf; Levin, Simon A; Dushoff, Jonathan

    2007-01-01

    Many pathogens exist in phenotypically distinct strains that interact with each other through competition for hosts. General models that describe such multi-strain systems are extremely difficult to analyze because their state spaces are enormously large. Reduced models have been proposed, but so far all of them necessarily allow for coinfections and require that immunity be mediated solely by reduced infectivity, a potentially problematic assumption. Here, we suggest a new state-space reduction approach that allows immunity to be mediated by either reduced infectivity or reduced susceptibility and that can naturally be used for models with or without coinfections. Our approach utilizes the general framework of status-based models. The cornerstone of our method is the introduction of immunity variables, which describe multi-strain systems more naturally than the traditional tracking of susceptible and infected hosts. Models expressed in this way can be approximated in a natural way by a truncation method that is akin to moment closure, allowing us to sharply reduce the size of the state space, and thus to consider models with many strains in a tractable manner. Applying our method to the phenomenon of antigenic drift in influenza A, we propose a potentially general mechanism that could constrain viral evolution to a one-dimensional manifold in a two-dimensional trait space. Our framework broadens the class of multi-strain systems that can be adequately described by reduced models. It permits computational, and even analytical, investigation and thus serves as a useful tool for understanding the evolution and ecology of multi-strain pathogens. PMID:17708677

  3. Linking structure to function: The search for active sites in non-platinum group metal oxygen reduction reaction catalysts

    SciTech Connect

    Holby, Edward F.; Zelenay, Piotr

    2016-05-17

    Atomic-scale structures of oxygen reduction reaction (ORR) active sites in non-platinum group metal (non-PGM) catalysts, made from pyrolysis of carbon, nitrogen, and transition-metal (TM) precursors have been the subject of continuing discussion in the fuel cell electrocatalysis research community. We found that quantum chemical modeling is a path forward for understanding of these materials and how they catalyze the ORR. Here, we demonstrate through literature examples of how such modeling can be used to better understand non-PGM ORR active site relative stability and activity and how such efforts can also aid in the interpretation of experimental signatures produced by these materials.

  4. Searching for magnetism in hydrogenated graphene: using highly hydrogenated graphene prepared via Birch reduction of graphite oxides.

    PubMed

    Eng, Alex Yong Sheng; Poh, Hwee Ling; Šaněk, Filip; Maryško, Miroslav; Matějková, Stanislava; Sofer, Zdeněk; Pumera, Martin

    2013-07-23

    Fully hydrogenated graphene (graphane) and partially hydrogenated graphene materials are expected to possess various fundamentally different properties from graphene. We have prepared highly hydrogenated graphene containing 5% wt of hydrogen via Birch reduction of graphite oxide using elemental sodium in liquid NH3 as electron donor and methanol as proton donor in the reduction. We also investigate the influence of preparation method of graphite oxide, such as the Staudenmaier, Hofmann or Hummers methods on the hydrogenation rate. A control experiment involving NaNH2 instead of elemental Na was also performed. The materials were characterized in detail by electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy both at room and low temperatures, X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectroscopy, combustible elemental analysis and electrical resistivity measurements. Magnetic measurements are provided of bulk quantities of highly hydrogenated graphene. In the whole temperature range up to room temperature, the hydrogenated graphene exhibits a weak ferromagnetism in addition to a contribution proportional to field that is caused not only by diamagnetism but also likely by an antiferromagnetic influence. The origin of the magnetism is also determined to arise from the hydrogenated graphene itself, and not as a result of any metallic impurities.

  5. Groundwater Monitoring Network Design Using a Space-Filling/ Bias-Reduction Heuristic

    NASA Astrophysics Data System (ADS)

    Yan, T.; Singh, A.; Kelley, V.; Deeds, N.

    2012-12-01

    Groundwater monitoring network design is one of the primary goals of groundwater management. In this study, a heuristic method for selecting wells to monitor groundwater flow is developed. The approach selects wells to a) maximize spread within the monitoring area (space-filling objective), b) reduce bias in estimate of groundwater level (drawdown objective) by selecting pairs of well proximal and distant from pumping areas. By selecting pairs of monitoring wells, this method is able to capture the largest and smallest drawdown in the study area while ensuring the newly added monitoring wells are at the greatest distance from existing monitoring wells. One of the advantages of this method is that it does not require water level information, obtained either from field measurements or groundwater model runs, which might be unavailable at the time of the monitoring network design; instead, this method utilizes pumping rates and locations thus can take future planning into consideration. If water level data is available then that may be included by considering it in the drawdown objective. A FORTRAN code is developed to implement this method. By changing the weighting factors, users have the flexibility on deciding the importance of pumping and spatial information to their network designs. The method has been successfully applied to monitoring network design in Upper Trinity County Groundwater Conservation District in Texas. Monitoring wells were selected from thousands of existing wells and added to the current monitoring network. The results support the decision maker on the number and distribution of a new groundwater network using existing wells. The study can be extended to improve the application of desired future condition (DFC) for Groundwater Conservation Districts in Texas.

  6. Linking structure to function: The search for active sites in non-platinum group metal oxygen reduction reaction catalysts

    DOE PAGES

    Holby, Edward F.; Zelenay, Piotr

    2016-05-17

    Atomic-scale structures of oxygen reduction reaction (ORR) active sites in non-platinum group metal (non-PGM) catalysts, made from pyrolysis of carbon, nitrogen, and transition-metal (TM) precursors have been the subject of continuing discussion in the fuel cell electrocatalysis research community. We found that quantum chemical modeling is a path forward for understanding of these materials and how they catalyze the ORR. Here, we demonstrate through literature examples of how such modeling can be used to better understand non-PGM ORR active site relative stability and activity and how such efforts can also aid in the interpretation of experimental signatures produced by thesemore » materials.« less

  7. Oxidation and reduction under cover: Chemistry at the confined space between ultra-thin nanoporous silicates and Ru(0001)

    SciTech Connect

    J. Anibal Boscoboinik; Zhong, Jian -Qiang; Kestell, John; Waluyo, Iradwikanari; Wilkins, Stuart; Mazzoli, Claudio; Barbour, Andi; Kaznatcheev, Konstantine; Shete, Meere; Tsapatsis, Michael

    2016-03-23

    The oxidation and reduction of Ru(0001) surfaces at the confined space between two-dimensional nanoporous silica frameworks and Ru(0001) have been investigated using synchrotron-based ambient pressure X-ray photoelectron spectroscopy (AP-XPS). The porous nature of the frameworks and the weak interaction between the silica and the ruthenium substrate allow oxygen and hydrogen molecules to go through the nanopores and react with the metal at the interface between the silica framework and the metal surface. In this work, three types of two-dimensional silica frameworks have been used to study their influence in the oxidation and reduction of the ruthenium surface at elevated pressures and temperatures. These frameworks are bilayer silica (0.5 nm thick), bilayer aluminosilicate (0.5 nm thick), and zeolite MFI nanosheets (3 nm thick). It is found that the silica frameworks stay essentially intact under these conditions, but they strongly affect the oxidation of ruthenium, with the 0.5 nm thick aluminosilicate bilayer completely inhibiting the oxidation. Furthermore, the latter is believed to be related to the lower chemisorbed oxygen content arising from electrostatic interactions between the negatively charged aluminosilicate framework and the Ru(0001) substrate.

  8. Oxidation and reduction under cover: Chemistry at the confined space between ultra-thin nanoporous silicates and Ru(0001)

    DOE PAGES

    J. Anibal Boscoboinik; Zhong, Jian -Qiang; Kestell, John; ...

    2016-03-23

    The oxidation and reduction of Ru(0001) surfaces at the confined space between two-dimensional nanoporous silica frameworks and Ru(0001) have been investigated using synchrotron-based ambient pressure X-ray photoelectron spectroscopy (AP-XPS). The porous nature of the frameworks and the weak interaction between the silica and the ruthenium substrate allow oxygen and hydrogen molecules to go through the nanopores and react with the metal at the interface between the silica framework and the metal surface. In this work, three types of two-dimensional silica frameworks have been used to study their influence in the oxidation and reduction of the ruthenium surface at elevated pressuresmore » and temperatures. These frameworks are bilayer silica (0.5 nm thick), bilayer aluminosilicate (0.5 nm thick), and zeolite MFI nanosheets (3 nm thick). It is found that the silica frameworks stay essentially intact under these conditions, but they strongly affect the oxidation of ruthenium, with the 0.5 nm thick aluminosilicate bilayer completely inhibiting the oxidation. Furthermore, the latter is believed to be related to the lower chemisorbed oxygen content arising from electrostatic interactions between the negatively charged aluminosilicate framework and the Ru(0001) substrate.« less

  9. Reduction of energy consumption in low rise residential space conditioning by retrofitting with evaporative condenser

    NASA Astrophysics Data System (ADS)

    Ndukaife, Theodore Aganachi

    will decrease. Intermittent operation of the water pump was also investigated and found to be beneficial to the system in terms of reduction in energy associated with the pump operation, and also prevention of water buildup in the flutes of the pad. Studies on water quality shows that water of high salinity (up to 35ppt), and turbidity (up to 30NTU) did not affect the evaporative cooling process, over the duration of usage. However, it is expected that over time, accumulation of salts, or other foreign materials on the pad surface will reduce the pad performance.

  10. Consumer's Guide to Radon Reduction

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Radon Share Facebook Twitter Google+ Pinterest Contact Us Consumer's Guide to Radon Reduction: How to Fix Your Home Contains information ...

  11. Reduction of the virtual space for coupled-cluster excitation energies of large molecules and embedded systems.

    PubMed

    Send, Robert; Kaila, Ville R I; Sundholm, Dage

    2011-06-07

    We investigate how the reduction of the virtual space affects coupled-cluster excitation energies at the approximate singles and doubles coupled-cluster level (CC2). In this reduced-virtual-space (RVS) approach, all virtual orbitals above a certain energy threshold are omitted in the correlation calculation. The effects of the RVS approach are assessed by calculations on the two lowest excitation energies of 11 biochromophores using different sizes of the virtual space. Our set of biochromophores consists of common model systems for the chromophores of the photoactive yellow protein, the green fluorescent protein, and rhodopsin. The RVS calculations show that most of the high-lying virtual orbitals can be neglected without significantly affecting the accuracy of the obtained excitation energies. Omitting all virtual orbitals above 50 eV in the correlation calculation introduces errors in the excitation energies that are smaller than 0.1 eV. By using a RVS energy threshold of 50 eV, the CC2 calculations using triple-ζ basis sets (TZVP) on protonated Schiff base retinal are accelerated by a factor of 6. We demonstrate the applicability of the RVS approach by performing CC2/TZVP calculations on the lowest singlet excitation energy of a rhodopsin model consisting of 165 atoms using RVS thresholds between 20 eV and 120 eV. The calculations on the rhodopsin model show that the RVS errors determined in the gas-phase are a very good approximation to the RVS errors in the protein environment. The RVS approach thus renders purely quantum mechanical treatments of chromophores in protein environments feasible and offers an ab initio alternative to quantum mechanics/molecular mechanics separation schemes.

  12. Alpha-band activity reflects reduction of mental effort in a comparison task: a source space analysis.

    PubMed

    Keil, Andreas; Mussweiler, Thomas; Epstude, Kai

    2006-11-22

    Comparison processes contribute to many core phenomena of social cognition research. Whenever humans judge a given target, they rely on comparisons with a pertinent standard. We propose that comparison processes may be so ubiquitous because they reduce mental effort. To investigate this possibility, we used dense-array Electroencephalogram (EEG) recordings together with a minimum norm source projection approach. As the dependent variable, we examined changes in parietal alpha (8-12 Hz) amplitude during a judgment task. Spectral changes in the alpha frequency range have been reliably related to attentional load, cognitive arousal, or mental effort. Two groups of participants (n=22) were procedurally primed to solve a series of target judgments in a more comparative (experimental group) versus more absolute (control group) manner. While the participants performed the critical judgment tasks, we recorded changes in alpha amplitude. Continuous EEG was transformed into a spherical source space using the minimum norm (L2) estimate and spectral changes were subsequently calculated in the source domain. Statistical parametric mapping in combination with permutation statistics was employed to map regions showing significant group differences. Results demonstrate that comparative processing was associated with smaller changes in alpha amplitude than absolute processing. This difference was most pronounced at parietal source locations, where alpha reduction was at a maximum. Temporal analysis suggested that this effect was present particularly during task preparation and execution. We conclude that comparative information processing may reduce mental effort in judgment tasks.

  13. Reduction in secondary dendrite arm spacing in cast eutectic Al-Si piston alloys by cerium addition

    NASA Astrophysics Data System (ADS)

    Ahmad, R.; Asmael, M. B. A.; Shahizan, N. R.; Gandouz, S.

    2017-01-01

    The effects of Ce on the secondary dendrite arm spacing (SDAS) and mechanical behavior of Al-Si-Cu-Mg alloys were investigated. The reduction of SDAS at different Ce concentrations was evaluated in a directional solidification experiment via computer-aided cooling curve thermal analysis (CA‒CCTA). The results showed that 0.1wt%-1.0wt% Ce addition resulted in a rapid solidification time, Δ t s, and low solidification temperature, Δ T S, whereas 0.1wt% Ce resulted in a fast solidification time, Δ t a-Al, of the α-Al phase. Furthermore, Ce addition refined the SDAS, which was reduced to approximately 36%. The mechanical properties of the alloys with and without Ce were investigated using tensile and hardness tests. The quality index ( Q) and ultimate tensile strength of (UTS) Al-Si-Cu-Mg alloys significantly improved with the addition of 0.1wt% Ce. Moreover, the base alloy hardness was improved with increasing Ce concentration.

  14. Axion Searches

    NASA Astrophysics Data System (ADS)

    Sikivie, Pierre

    The following sections are included: * INTRODUCTION TO AXION PHYSICS * THE COSMOLOGICAL AXION ENERGY DENSITY * The contribution from initial vacuum misalignment * The contribution from cosmic axion strings * THE CAVITY DETECTOR OF GALACTIC HALO AXIONS * THE PHASE SPACE STRUCTURE OF COLD DARK MATTER HALOS * TELESCOPE SEARCH FOR THE 2γ DECAY OF RELIC AXIONS * A SOLAR AXION DETECTOR * ACKNOWLEDGEMENT * REFERENCES

  15. HUBBLE SPACE TELESCOPE PROPER MOTION (HSTPROMO) CATALOGS OF GALACTIC GLOBULAR CLUSTERS. I. SAMPLE SELECTION, DATA REDUCTION, AND NGC 7078 RESULTS

    SciTech Connect

    Bellini, A.; Anderson, J.; Van der Marel, R. P.; Watkins, L. L.; King, I. R.; Bianchini, P.; Chanamé, J.; Chandar, R.; Cool, A. M.; Ferraro, F. R.; Massari, D.; Ford, H.

    2014-12-20

    We present the first study of high-precision internal proper motions (PMs) in a large sample of globular clusters, based on Hubble Space Telescope (HST) data obtained over the past decade with the ACS/WFC, ACS/HRC, and WFC3/UVIS instruments. We determine PMs for over 1.3 million stars in the central regions of 22 clusters, with a median number of ∼60,000 stars per cluster. These PMs have the potential to significantly advance our understanding of the internal kinematics of globular clusters by extending past line-of-sight (LOS) velocity measurements to two- or three-dimensional velocities, lower stellar masses, and larger sample sizes. We describe the reduction pipeline that we developed to derive homogeneous PMs from the very heterogeneous archival data. We demonstrate the quality of the measurements through extensive Monte Carlo simulations. We also discuss the PM errors introduced by various systematic effects and the techniques that we have developed to correct or remove them to the extent possible. We provide in electronic form the catalog for NGC 7078 (M 15), which consists of 77,837 stars in the central 2.'4. We validate the catalog by comparison with existing PM measurements and LOS velocities and use it to study the dependence of the velocity dispersion on radius, stellar magnitude (or mass) along the main sequence, and direction in the plane of the sky (radial or tangential). Subsequent papers in this series will explore a range of applications in globular-cluster science and will also present the PM catalogs for the other sample clusters.

  16. A Hybrid Color Space for Skin Detection Using Genetic Algorithm Heuristic Search and Principal Component Analysis Technique

    PubMed Central

    2015-01-01

    Color is one of the most prominent features of an image and used in many skin and face detection applications. Color space transformation is widely used by researchers to improve face and skin detection performance. Despite the substantial research efforts in this area, choosing a proper color space in terms of skin and face classification performance which can address issues like illumination variations, various camera characteristics and diversity in skin color tones has remained an open issue. This research proposes a new three-dimensional hybrid color space termed SKN by employing the Genetic Algorithm heuristic and Principal Component Analysis to find the optimal representation of human skin color in over seventeen existing color spaces. Genetic Algorithm heuristic is used to find the optimal color component combination setup in terms of skin detection accuracy while the Principal Component Analysis projects the optimal Genetic Algorithm solution to a less complex dimension. Pixel wise skin detection was used to evaluate the performance of the proposed color space. We have employed four classifiers including Random Forest, Naïve Bayes, Support Vector Machine and Multilayer Perceptron in order to generate the human skin color predictive model. The proposed color space was compared to some existing color spaces and shows superior results in terms of pixel-wise skin detection accuracy. Experimental results show that by using Random Forest classifier, the proposed SKN color space obtained an average F-score and True Positive Rate of 0.953 and False Positive Rate of 0.0482 which outperformed the existing color spaces in terms of pixel wise skin detection accuracy. The results also indicate that among the classifiers used in this study, Random Forest is the most suitable classifier for pixel wise skin detection applications. PMID:26267377

  17. Nonlinear dimensionality reduction of CT histogram based feature space for predicting recurrence-free survival in non-small-cell lung cancer

    NASA Astrophysics Data System (ADS)

    Kawata, Y.; Niki, N.; Ohmatsu, H.; Aokage, K.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.

    2015-03-01

    Advantages of CT scanners with high resolution have allowed the improved detection of lung cancers. In the recent release of positive results from the National Lung Screening Trial (NLST) in the US showing that CT screening does in fact have a positive impact on the reduction of lung cancer related mortality. While this study does show the efficacy of CT based screening, physicians often face the problems of deciding appropriate management strategies for maximizing patient survival and for preserving lung function. Several key manifold-learning approaches efficiently reveal intrinsic low-dimensional structures latent in high-dimensional data spaces. This study was performed to investigate whether the dimensionality reduction can identify embedded structures from the CT histogram feature of non-small-cell lung cancer (NSCLC) space to improve the performance in predicting the likelihood of RFS for patients with NSCLC.

  18. Reduction of Z classification of a two-dimensional weak topological insulator: Real-space dynamical mean-field theory study

    NASA Astrophysics Data System (ADS)

    Yoshida, Tsuneya; Kawakami, Norio

    2017-01-01

    One of the remarkable interaction effects on topological insulators is the reduction of topological classification in free-fermion systems. We address this issue in a bilayer honeycomb lattice model by taking into account temperature effects on the reduction. Our analysis, based on the real-space dynamical mean-field theory, elucidates the following results. (i) Even when the reduction occurs, the winding number defined by the Green's function can take a nontrivial value at zero temperature. (ii) The winding number taking the nontrivial value becomes consistent with the absence of gapless edge modes due to Mott behaviors emerging only at the edges. (iii) Temperature effects can restore the gapless edge modes, provided that the energy scale of interactions is smaller than the bulk gap. In addition, we observe the topological edge Mott behavior only in some finite-temperature region.

  19. SEARCHING FOR TROJAN ASTEROIDS IN THE HD 209458 SYSTEM: SPACE-BASED MOST PHOTOMETRY AND DYNAMICAL MODELING

    SciTech Connect

    Moldovan, Reka; Matthews, Jaymie M.; Gladman, Brett; Bottke, William F.; Vokrouhlicky, David

    2010-06-10

    We have searched Microvariability and Oscillations of Stars (MOST) satellite photometry obtained in 2004, 2005, and 2007 of the solar-type star HD 209458 for Trojan asteroid swarms dynamically coupled with the system's transiting 'hot Jupiter' HD 209458b. Observations of the presence and nature of asteroids around other stars would provide unique constraints on migration models of exoplanetary systems. Our results set an upper limit on the optical depth of Trojans in the HD 209458 system that can be used to guide current and future searches of similar systems by upcoming missions. Using cross-correlation methods with artificial signals implanted in the data, we find that our detection limit corresponds to a relative Trojan transit depth of 1 x10{sup -4}, equivalent to {approx}1 lunar mass of asteroids, assuming power-law Trojan size distributions similar to Jupiter's Trojans in our solar system. We confirm with dynamical interpretations that some asteroids could have migrated inward with the planet to its current orbit at 0.045 AU, and that the Yarkovsky effect is ineffective at eliminating objects of >1 m in size. However, using numerical models of collisional evolution we find that, due to high relative speeds in this confined Trojan environment, collisions destroy the vast majority of the asteroids in <10 Myr. Our modeling indicates that the best candidates to search for exoTrojan swarms in 1:1 mean resonance orbits with 'hot Jupiters' are young systems (ages of about 1 Myr or less). Years of Kepler satellite monitoring of such a system could detect an asteroid swarm with a predicted transit depth of 3 x 10{sup -7}.

  20. Directed searches for continuous gravitational waves from binary systems: Parameter-space metrics and optimal Scorpius X-1 sensitivity

    NASA Astrophysics Data System (ADS)

    Leaci, Paola; Prix, Reinhard

    2015-05-01

    We derive simple analytic expressions for the (coherent and semicoherent) phase metrics of continuous-wave sources in low-eccentricity binary systems for the two regimes of long and short segments compared to the orbital period. The resulting expressions correct and extend previous results found in the literature. We present results of extensive Monte Carlo studies comparing metric mismatch predictions against the measured loss of detection statistics for binary parameter offsets. The agreement is generally found to be within ˜10 %- 30 % . For an application of the metric template expressions, we estimate the optimal achievable sensitivity of an Einstein@Home directed search for Scorpius X-1, under the assumption of sufficiently small spin wandering. We find that such a search, using data from the upcoming advanced detectors, would be able to beat the torque-balance level [R. V. Wagoner, Astrophys. J. 278, 345 (1984); L. Bildsten, Astrophys. J. 501, L89 (1998).] up to a frequency of ˜500 - 600 Hz , if orbital eccentricity is well constrained, and up to a frequency of ˜160 - 200 Hz for more conservative assumptions about the uncertainty on orbital eccentricity.

  1. MOST space-based photometry of the transiting exoplanet system HD 209458: II. Search for transits at other periods

    NASA Astrophysics Data System (ADS)

    Croll, B.; Matthews, J. M.; Rowe, J. F.; Kuschnig, R.; Sasselov, D.; Lin, D.; Guenther, D. B.; Moffat, A. F. J.; Rucinski, S. M.; Walker, G. A. H.; Weiss, W. W.

    2005-12-01

    We have obtained nearly uninterrupted broadband optical photometry of the transiting exoplanet system HD 209458 with the MOST (Microvariability & Oscillation of STars) satellite: 14 days in 2004 and 44 days in 2005. We are searching these data for evidence of transits caused by other bodies in the same orbital plane as the known planet HD 209458b. This, in part, will test some theories of the dynamical stabilisation of that planet's small orbit which invoke other smaller bodies in similar orbits undergoing momentum interactions. Preliminary analysis of the 2004 data rules out any bodies with periods of 1 week or shorter with radii greater than about 0.3 Jupiter radii (about 3 Earth radii). The 2005 data quadrupule the total time coverage and should lower that detection threshold in radius and increase it in period. The analysis of the entire data set is currently in progress.

  2. Search for Near-Earth Object with Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) Assets

    NASA Technical Reports Server (NTRS)

    Helin, Eleanor F.

    1993-01-01

    This is a brief review of recent plans and current status of the adaptation of an Air Force wide field GEODSS telescope for the discovery and follow-up of Near-Earth Objects (NEOs). The proposed search program will focus on the discovery of natural objects and will proceed on a non-interference basis, i.e. avoiding any impact on GEODSS' dedicated purpose of tracking and monitoring Earth orbiting spacecraft. In September, 1992, JPL representatives had an initial meeting with GEODSS personnel and saw their facilities in Maui where use of GEODSS' telescopes were discussed in terms of using these existing sensors for the detection of NEOs. A result of these meetings was a test run at the GEODSS, Socorro, N. Mexico location to evaluate the tracking and astrometric accuracy of an upcoming close approach of NEA, (4179) Toutatis...

  3. Plastics and elastomers: Space applications. (Latest citations from the Rubber and Plastics Research Association database). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    The bibliography contains citations concerning thermoplastic and thermosetting resins used for space environments. Among the properties examined for selected polymers are ultraviolet light sensitivity, radiation resistivity, sensitivity to extreme temperatures, adhesion qualities, strength, and insulation value. Fiber reinforced plastics, nylon, vinyl, cellular plastics, epoxy resin, PTFE, and elastomers are described. The citations also reference manufacturers, tradenames, marketing trends, performance results, and specific applications. (Contains a minimum of 80 citations and includes a subject term index and title list.)

  4. Highly flexible nearest-neighbor-search associative memory with integrated k nearest neighbor classifier, configurable parallelism and dual-storage space

    NASA Astrophysics Data System (ADS)

    An, Fengwei; Mihara, Keisuke; Yamasaki, Shogo; Chen, Lei; Jürgen Mattausch, Hans

    2016-04-01

    VLSI-implementations are often applied to solve the high computational cost of pattern matching but have usually low flexibility for satisfying different target applications. In this paper, a digital word-parallel associative memory architecture for k nearest neighbor (KNN) search, which is one of the most basic algorithms in pattern recognition, is reported applying the squared Euclidean distance measure. The reported architecture features reconfigurable parallelism, dual-storage space to achieve a flexible number of reference vectors, and a dedicated majority vote circuit. Programmable switching circuits, located between vector components, enable scalability of the searching parallelism by configuring the reference feature-vector dimensionality. A pipelined storage with dual static-random-access-memory (SRAM) cells for each unit and an intermediate winner control circuit are designed to extend the applicability by improving the flexibility of the reference storage. A test chip in 180 nm CMOS technology, which has 32 rows, 4 elements in each row and 2-parallel 8-bit dual-components in each element, consumes altogether 61.4 mW and in particular only 11.9 mW during the reconfigurable KNN classification (at 45.58 MHz and 1.8 V).

  5. The quest for complex molecules in space. Searches for cyanides related to n-propyl cyanide in Sgr B2(N)

    NASA Astrophysics Data System (ADS)

    Muller, H. S. P.; Belloche, A.; Menten, K. M.; Coutens, A.; Walters, A.; Grabow, J. U.; Schlemmer, S.

    2011-05-01

    A molecular line survey was carried out with the IRAM 30 m telecope toward the prolific hot core Sgr B2(N) in order to explore its molecular complexity. The entire 3 mm range as well as selected regions at 2 and 1.3 mm were covered. Notable results include the detections of aminoacetonitrile, ethyl formate, n-propyl cyanide, and the singly substituted 13C isotopologs of vinyl cyanide. There exists a branched isomer of n-propyl cyanide: iso-propyl cyanide. A search for this isomer in our line survey required a laboratory spectroscopic investigation beforehand. Even though promising emission features have been found for this as well as other, related molecules, there are rather few uncontaminated lines. Overlap by other emission or some absorption features occurs frequently, and uncertainties about the position of the baseline also contribute to considering detections to be inconclusive. Nevertheless, the determination of upper limits or abundances among isomers and related molecules will help to contrain astrochemical pathways. We will present our results and discuss promising strategies to search for complex molecules in space.

  6. State-space representation of Li-ion battery porous electrode impedance model with balanced model reduction

    NASA Astrophysics Data System (ADS)

    Jun, Myungsoo; Smith, Kandler; Graf, Peter

    2015-01-01

    This paper presents an approximate time-domain solution for physics-based electrochemical lithium-ion cell battery models. The time-domain solution is represented in state-space form and can be easily used for the design of a state estimator or controller. It uses an interconnection-of-system approach to derive a state-space representation of a battery impedance model and provides a reduced order model based via the balanced truncation method. Simulation results are also provided to show the performance of the proposed model in the frequency domain.

  7. SEMICONDUCTOR TECHNOLOGY: Reduction of proximity effect in fabricating nanometer-spaced nanopillars by two-step exposure

    NASA Astrophysics Data System (ADS)

    Yang, Zhang; Renping, Zhang; Weihua, Han; Jian, Liu; Xiang, Yang; Ying, Wang; Chian Chiu, Li; Fuhua, Yang

    2009-11-01

    A two-step exposure method to effectively reduce the proximity effect in fabricating nanometer-spaced nanopillars is presented. In this method, nanopillar patterns on poly-methylmethacrylate (PMMA) were partly cross-linked in the first-step exposure. After development, PMMA between nanopillar patterns was removed, and hence the proximity effect would not take place there in the subsequent exposure. In the second-step exposure, PMMA masks were completely cross-linked to achieve good resistance in inductively coupled plasma etching. Accurate pattern transfer of rows of nanopillars with spacing down to 40 nm was realized on a silicon-on-insulator substrate.

  8. Search for evidence of life in space: analysis of enantiomeric organic molecules by N,N-dimethylformamide dimethylacetal derivative dependant Gas Chromatography-Mass Spectrometry.

    PubMed

    Freissinet, C; Buch, A; Sternberg, R; Szopa, C; Geffroy-Rodier, C; Jelinek, C; Stambouli, M

    2010-01-29

    Within the context of the future space missions to Mars (MSL 2011 and Exomars 2016), which aim at searching for traces of life at the surface, the detection and quantitation of enantiomeric organic molecules is of major importance. In this work, we have developed and optimized a method to derivatize and analyze chiral organic molecules suitable for space experiments, using N,N-dimethylformamide dimethylacetal (DMF-DMA) as the derivatization agent. The temperature, duration of the derivatization reaction, and chromatographic separation parameters have been optimized to meet instrument design constraints imposed upon space experiment devices. This work demonstrates that, in addition to its intrinsic qualities, such as production of light-weight derivatives and a great resistance to drastic operating conditions, DMF-DMA facilitates simple and fast derivatization of organic compounds (three minutes at 140 degrees C in a single-step) that is suitable for an in situ analysis in space. By using DMF-DMA as the derivatization agent, we have successfully identified 19 of the 20 proteinic amino acids and been able to enantiomerically separate ten of the potential 19 (glycine being non-chiral). Additionally, we have minimized the percentage of racemized amino acid compounds produced by optimizing the conditions of the derivatization reaction itself. Quantitative linearity studies and the determination of the limit of detection show that the proposed method is also suitable for the quantitative determination of both enantiomeric forms of most of the tested amino acids, as limits of detection obtained are lower than the ppb level of organic molecules already detected in Martian meteorites.

  9. Millimeter Wave Spectra of Methyl Cyanate, Methoxyamine and N-Methylhydroxylamine Laboratory Studies and Astronomical Search in Space

    NASA Astrophysics Data System (ADS)

    Kolesniková, Lucie; Alonso, José L.; Bermúdez, Celina; Alonso, E. R.; Tercero, Belén; Cernicharo, Jose; Guillemin, J.-C.

    2016-06-01

    Recent discovery of methyl isocyanate (CH3NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH3OCN) a potential molecule in the interstellar medium. Methoxyamine (CH3ONH2) and its isomeric form N-methylhydroxylamine (CH3NHOH) may be considered as a potential interstellar amines. Pure rotational transitions belonging to the ground state and several excited vibrational states were measured and analyzed up to 400 GHz. Rotational transitions revealed A-E splitting due to the methyl internal rotation and were globally analyzed in order to provide a precise set of the spectroscopic constants. Results of this work were used to search for the spectral features of methyl cyanate in Orion KL, Sgr B2(N), B1-b and TMC-1 molecular clouds. D. T. Halfen, V. V. Ilyushin, L. Ziurys, Astrophys. J. Lett., 2015, 812, L5. J. Cernicharo, Z. Kisiel, B. Tercero, L. Kolesniková, I. R. Medvedev et. al., Astron. & Astrophys., 2016, 587, L4. R. T. Garrod, S. L. Widicus Weaver, E. Herbst, Astrophys. J., 2008, 682, 283. L. Kolesniková, J. L. Alonso, C. Bermudez, E. R. Alonso, J. Cernicharo et. al., Astron. & Astrophys., 2016, accepted.

  10. [Warning! A crucial period of searching for life on Mars--why international criterion for space quarantine is now required].

    PubMed

    Koike, J

    1996-12-01

    In connection with quarantine for interplanetary mission, we have examined the survivalities of terrestrial microorganisms under simulated Mars condition. In this study, the Mars conditions were simulated by ultraviolet and proton irradiation under similar low temperature, high vacuum and gaseous conditions by using cryostat vehicle. After exposure to the simulated Mars conditions, the survivabilities of the organisms were examined. From the results, the spores of Bacillus subtilis, the spores of Aspergillus niger, some anaerobic bacteria and algae showed considerable high survivalities even after UV and proton irradiations corresponding to 200 years on Mars. This subject is not restricted to academic curiosity but concerns problems involving the contamination of Mars with terrestrial organisms carried by space-probes. If there is a possibility that the terrestrial organisms carried from Earth to Mars can live for a significant period on Mars, a contamination of the Mars should be prevented for the purpose of life-detection-experiments in future.

  11. Multiple Simulated Annealing-Molecular Dynamics (MSA-MD) for Conformational Space Search of Peptide and Miniprotein.

    PubMed

    Hao, Ge-Fei; Xu, Wei-Fang; Yang, Sheng-Gang; Yang, Guang-Fu

    2015-10-23

    Protein and peptide structure predictions are of paramount importance for understanding their functions, as well as the interactions with other molecules. However, the use of molecular simulation techniques to directly predict the peptide structure from the primary amino acid sequence is always hindered by the rough topology of the conformational space and the limited simulation time scale. We developed here a new strategy, named Multiple Simulated Annealing-Molecular Dynamics (MSA-MD) to identify the native states of a peptide and miniprotein. A cluster of near native structures could be obtained by using the MSA-MD method, which turned out to be significantly more efficient in reaching the native structure compared to continuous MD and conventional SA-MD simulation.

  12. Enabling and Enhancing Space Mission Success and Reduction of Risk through the Application of an Integrated Data Architecture

    NASA Technical Reports Server (NTRS)

    Brummett, Robert C.

    2008-01-01

    The engineering phases of design, development, test, and evaluation (DDT and E) and subsequent planning, preparation, and operation (Ops) of space vehicles in a complex and distributed environment requires massive and continuous flows of information across the enterprise and across temporal stages of the vehicle lifecycle. The resulting capabilities at each subsequent stage depend in part on the capture, preparation, storage, and subsequent provision of information from prior stages. The United States National Aeronautics and Space Administration (NASA) is currently designing a fleet of new vehicles that will replace the Space Shuttle and expand space operations and exploration capabilities. This includes the 2 stage human rated lift vehicle Ares 1 and its associated crew vehicle the Orion, and a service module; the heavy lift cargo vehicle, Ares 5, and an associated cargo stage known as the Earth Departure Stage; and a Lunar Lander vehicle that contains a descent stage, and ascent stage, and a habitation module. A variety of concurrent assorted ground operations infrastructure including software and facilities are also being developed, assorted technology and assembly designs and development for equipment such as EVA suits, life support systems, command and control technologies are also in the pipeline. The development is occurring in a distributed manner, with project deliverables being contributed by a large and diverse assortment of vendors and most space faring nations. Critical information about all of the components, software, and procedures must be shared during the DDT and E phases and then made readily available to the mission operations staff for access during the planning, preparation, and operations phases, and also need to be readily available for system to system interactions. The Constellation Data Systems Project (CxDS) is identifying the needs, and designing and deploying systems and processes to support these needs. This paper details the steps

  13. Arioc: high-throughput read alignment with GPU-accelerated exploration of the seed-and-extend search space.

    PubMed

    Wilton, Richard; Budavari, Tamas; Langmead, Ben; Wheelan, Sarah J; Salzberg, Steven L; Szalay, Alexander S

    2015-01-01

    When computing alignments of DNA sequences to a large genome, a key element in achieving high processing throughput is to prioritize locations in the genome where high-scoring mappings might be expected. We formulated this task as a series of list-processing operations that can be efficiently performed on graphics processing unit (GPU) hardware.We followed this approach in implementing a read aligner called Arioc that uses GPU-based parallel sort and reduction techniques to identify high-priority locations where potential alignments may be found. We then carried out a read-by-read comparison of Arioc's reported alignments with the alignments found by several leading read aligners. With simulated reads, Arioc has comparable or better accuracy than the other read aligners we tested. With human sequencing reads, Arioc demonstrates significantly greater throughput than the other aligners we evaluated across a wide range of sensitivity settings. The Arioc software is available at https://github.com/RWilton/Arioc. It is released under a BSD open-source license.

  14. Learning in robotic manipulation: The role of dimensionality reduction in policy search methods. Comment on "Hand synergies: Integration of robotics and neuroscience for understanding the control of biological and artificial hands" by Marco Santello et al.

    NASA Astrophysics Data System (ADS)

    Ficuciello, Fanny; Siciliano, Bruno

    2016-07-01

    learning into control naturally leads to relaxing the above requirements through the adoption of coordinated motion patterns and sensory-motor synergies as useful tools leading to a problem of reduced dimension. To this purpose, model-based control strategies relying on synergistic models of manipulation activities learned from human experience can be integrated with real-time learning from actions strategies [5]. In [6] a classification of learning strategies for robotics is provided, while the difference between imitation learning and reinforcement learning (RL) is highlighted in [7]. From recent research in the field [8,9], it seems that RL represents the future toward autonomous and intelligent robots since it provides learning capabilities as those of humans, i.e. based on exploration and trial-and-error policies. In this context, suitable policy search methods to be implemented in a synergy-based framework are to be sought in order to reduce the search space dimension while guaranteeing the convergence and efficiency of the learning algorithm.

  15. MOST Space-based Photometry of the Transiting Exoplanet System HD 209458: Transit Timing to Search for Additional Planets

    NASA Astrophysics Data System (ADS)

    Miller-Ricci, Eliza; Rowe, Jason F.; Sasselov, Dimitar; Matthews, Jaymie M.; Guenther, David B.; Kuschnig, Rainer; Moffat, Anthony F. J.; Rucinski, Slavek M.; Walker, Gordon A. H.; Weiss, Werner W.

    2008-07-01

    We report on the measurement of transit times for the HD 209458 planetary system from photometry obtained with the MOST (Microvariability and Oscillations of Stars) space telescope. Deviations from a constant orbital period can indicate the presence of additional planets in the system that are yet undetected, potentially with masses approaching an Earth mass. The MOST data sets of HD 209458 from 2004 and 2005 represent unprecedented time coverage with nearly continuous observations spanning 14 and 43 days and monitoring three transits and 12 consecutive transits, respectively. The transit times that we obtain show no variations on three scales: (1) no long-term change in P since before 2004 at 25 ms level, (2) no trend in transit timings during the 2005 run, and (3) no individual transit timing deviations above 80 s level. Together with previously published transit times from Agol & Steffen, this allows us to place limits on the presence of additional close-in planets in the system, in some cases down to below an Earth mass. This result, along with previous radial velocity work, now eliminates the possibility that a perturbing planet could be responsible for the additional heat source needed to explain HD 209458b's anomalous low density.

  16. Key issues for the strategic-offensive-force reduction portion of the nuclear and space talks in Geneva. Interim report

    SciTech Connect

    Warner, E.L.; Kent, G.A.; DeValk, R.J.

    1985-12-01

    This note discusses approaches for the limitation and reduction of U.S. and Soviet strategic attack forces. It identifies three national security objectives that the United States and, arguably, the Soviet Union seek to obtain through a combination of strategic nuclear force deployments, arms control, and diplomacy: credible deterrence, strategic, crisis stability, and essential equivalence. It defines three measures that can be controlled to constrain the destructive capacity of intercontinental strategic attack forces: the amount of ballistic missile throwweight, the number of ballistic missile RVs, and the amount of bomber gross takeoff weight. It then considers an alternative approach, a weighted composite measure that yields a smaller initial difference between U.S. and Soviet ballistic missile forces than the pure throwweight approach, thus providing better prospects for successful compromise in negotiation. It concludes that the United States cannot reasonably expect to gain any treaty significant reductions in Soviet ballistic missile capabilities without being prepared to accept considerable constraints on the growth of the U.S. bomber force weapon-carrying potential.

  17. Stringent constraints on the dark matter annihilation cross section from subhalo searches with the Fermi Gamma-Ray Space Telescope

    NASA Astrophysics Data System (ADS)

    Berlin, Asher; Hooper, Dan

    2014-01-01

    The dark matter halo of the Milky Way is predicted to contain a very large number of smaller subhalos. As a result of the dark matter annihilations taking place within such objects, the most nearby and massive subhalos could appear as pointlike or spatially extended gamma-ray sources, without observable counterparts at other wavelengths. In this paper, we use the results of the Aquarius simulation to predict the distribution of nearby subhalos and compare this to the characteristics of the unidentified gamma-ray sources observed by the Fermi Gamma-Ray Space Telescope. Focusing on the brightest high latitude sources, we use this comparison to derive limits on the dark matter annihilation cross section. For dark matter particles lighter than ˜200 GeV, the resulting limits are the strongest obtained to date, being modestly more stringent than those derived from observations of dwarf galaxies or the Galactic center. We also derive independent limits based on the lack of unidentified gamma-ray sources with discernible spatial extension, but these limits are a factor of ˜2-10 weaker than those based on pointlike subhalos. Lastly, we note that four of the ten brightest high-latitude sources exhibit a similar spectral shape, consistent with 30-60 GeV dark matter particles annihilating to bb¯ with an annihilation cross section on the order of σv ˜(5-10)×10-27 cm3/s or 8-10 GeV dark matter particles annihilating to τ+τ- with σv ˜(1.5-3.0)×10-27 cm3/s.

  18. The effects of task difficulty, novelty and the size of the search space on intrinsically motivated exploration.

    PubMed

    Baranes, Adrien F; Oudeyer, Pierre-Yves; Gottlieb, Jacqueline

    2014-01-01

    Devising efficient strategies for exploration in large open-ended spaces is one of the most difficult computational problems of intelligent organisms. Because the available rewards are ambiguous or unknown during the exploratory phase, subjects must act in intrinsically motivated fashion. However, a vast majority of behavioral and neural studies to date have focused on decision making in reward-based tasks, and the rules guiding intrinsically motivated exploration remain largely unknown. To examine this question we developed a paradigm for systematically testing the choices of human observers in a free play context. Adult subjects played a series of short computer games of variable difficulty, and freely choose which game they wished to sample without external guidance or physical rewards. Subjects performed the task in three distinct conditions where they sampled from a small or a large choice set (7 vs. 64 possible levels of difficulty), and where they did or did not have the possibility to sample new games at a constant level of difficulty. We show that despite the absence of external constraints, the subjects spontaneously adopted a structured exploration strategy whereby they (1) started with easier games and progressed to more difficult games, (2) sampled the entire choice set including extremely difficult games that could not be learnt, (3) repeated moderately and high difficulty games much more frequently than was predicted by chance, and (4) had higher repetition rates and chose higher speeds if they could generate new sequences at a constant level of difficulty. The results suggest that intrinsically motivated exploration is shaped by several factors including task difficulty, novelty and the size of the choice set, and these come into play to serve two internal goals-maximize the subjects' knowledge of the available tasks (exploring the limits of the task set), and maximize their competence (performance and skills) across the task set.

  19. Stringent constraints on the dark matter annihilation cross section from subhalo searches with the Fermi Gamma-Ray Space Telescope

    SciTech Connect

    Berlin, Asher; Hooper, Dan

    2014-01-01

    The dark matter halo of the Milky Way is predicted to contain a very large number of smaller subhalos. As a result of the dark matter annihilations taking place within such objects, the most nearby and massive subhalos could appear as point-like or spatially extended gamma-ray sources, without observable counterparts at other wavelengths. In this paper, we use the results of the Aquarius simulation to predict the distribution of nearby subhalos, and compare this to the characteristics of the unidentified gamma-ray sources observed by the Fermi Gamma-Ray Space Telescope. Focusing on the brightest high latitude sources, we use this comparison to derive limits on the dark matter annihilation cross section. For dark matter particles lighter than ~200 GeV, the resulting limits are the strongest obtained to date, being modestly more stringent than those derived from observations of dwarf galaxies or the Galactic Center. We also derive independent limits based on the lack of unidentified gamma-ray sources with discernible spatial extension, but these limits are a factor of ~2-10 weaker than those based on point-like subhalos. Lastly, we note that four of the ten brightest high-latitude sources exhibit a similar spectral shape, consistent with 30-60 GeV dark matter particles annihilating to b quarks with an annihilation cross section on the order of sigma v ~ (5-10) x 10^-27 cm^3/s, or 8-10 GeV dark matter particles annihilating to taus with sigma v ~ (2.0-2.5) x 10^-27 cm^3/s.

  20. Green residues from Bangkok green space for renewable energy recovery, phosphorus recycling and greenhouse gases emission reduction.

    PubMed

    Thitanuwat, Bussarakam; Polprasert, Chongchin; Englande, Andrew J

    2017-03-01

    Effective ways to integrate human life quality, environmental pollution mitigation and efficient waste management strategies are becoming a crisis challenge for sustainable urban development. The aims of this study are: (1) to evaluate and recommend an optimum Urban Green Space (UGS) area for the Bangkok Metropolitan Administration (BMA); and (2) to quantify potential renewable resources including electricity generation and potential nutrient recovery from generated ash. Green House Gases (GHGs) emissions from the management of Green Residues (GR) produced in a recommended UGS expansion are estimated and compared with those from the existing BMA waste management practice. Results obtained from this study indicate that an increase in UGS from its current 2.02% to 22.4% of the BMA urban area is recommended. This optimum value is primarily due to the area needed as living space for its population. At this scale, GR produced of about 334kt·y(-1) may be used to generate electricity at the rate of 206GWh·y(-1) by employing incineration technology. Additionally, instead of going to landfill, phosphorus (P) contained in the ash of 1077 t P·y(-1) could be recovered to produce P fertilizer to be recycled for agricultural cultivation. Income earned from selling these products is found to offset all of the operational cost of the proposed GR management methodology itself plus 7% of the cost of BMA's Municipal Solid Waste (MSW) operations. About 70% of the current GHGs emission may be reduced based on incineration simulation.

  1. The Quest for Complex Molecules in Space. Searches for Cyanides Related to n-PROPYL Cyanide in SGR B2(N)

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.; Schlemmer, S.; Belloche, A.; Menten, K. M.; Coutens, A.; Walters, A.; Grabow, J.-U.

    2011-06-01

    A molecular line survey was carried out with the IRAM 30 m telescope toward the prolific hot core Sgr B2(N) in order to explore its molecular complexity. The entire 3 mm range as well as selected regions at 2 and 1.3 mm were covered. Notable results include the detections of aminoacetonitrile, ethyl formate, n-propyl cyanide,^b and the singly substituted 13C isotopologs of vinyl cyanide. There exists a branched isomer of n-propyl cyanide: iso-propyl cyanide. A search for this isomer in our line survey required a laboratory spectroscopic investigation beforehand. Even though promising emission features have been found for this as well as other, related molecules, there are rather few uncontaminated lines. Overlap by other emission or some absorption features occurs frequently, and uncertainties about the position of the baseline also contribute to considering detections to be inconclusive. Nevertheless, the determination of upper limits or abundances among isomers and related molecules will help to constrain astrochemical pathways. We will present our results and discuss promising strategies to search for complex molecules in space. A. Belloche, K. M. Menten, C. Comito, H. S. P. Müller, P. Schilke, J. Ott, S. Thorwirth, C. Hieret, Astron. Astrophys. 482 (2008) 179. A. Belloche, R. T. Garrod, H. S. P. Müller, K. M. Menten, C. Comito, P. Schilke, Astron. Astrophys. 499 (2009), 215. H. S. P. Müller, A. Belloche, K. M. Menten, C. Comito, P. Schilke, J. Mol. Spectrosc. 251 (2008) 319. H. S. P. Müller, A. Coutens, A. Walters, J.-U. Grabow, S. Schlemmer, submitted to J. Mol. Spectrosc.

  2. Optimal probabilistic search

    SciTech Connect

    Lokutsievskiy, Lev V

    2011-05-31

    This paper is concerned with the optimal search of an object at rest with unknown exact position in the n-dimensional space. A necessary condition for optimality of a trajectory is obtained. An explicit form of a differential equation for an optimal trajectory is found while searching over R-strongly convex sets. An existence theorem is also established. Bibliography: 8 titles.

  3. CO2 Compressor Requirements for Integration of Space Station Carbon Dioxide Removal and Carbon Dioxide Reduction Assemblies

    NASA Technical Reports Server (NTRS)

    Jeng, Frank F.; Lewis, John F.; Graf, John; LaFuse, Sharon; Nicholson, Leonard S. (Technical Monitor)

    1999-01-01

    This paper describes the analysis on integration requirements, CO2 compressor in particular, for integration of Carbon Dioxide Removal Assembly (CDRA) and CO2 Reduction Assembly (CRA) as a part of the Node 3 project previously conducted at JSC/NASA. A system analysis on the volume and operation pressure range of the CO2 accumulator was conducted. The hardware and operational configurations of the CO2 compressor were developed. The performance and interface requirements of the compressor were specified. An existing Four-Bed Molecular Sieve CO2 removal computer model was modified into a CDRA model and used in analyzing the requirements of the CDRA CO2 compressor. This CDRA model was also used in analyzing CDRA operation parameters that dictate CO2 pump sizing. Strategy for the pump activation was also analyzed.

  4. Reduction of astrometric plates

    NASA Technical Reports Server (NTRS)

    Stock, J.

    1984-01-01

    A rapid and accurate method for the reduction of comet or asteroid plates is described. Projection equations, scale length correction, rotation of coordinates, linearization, the search for additional reference stars, and the final solution are examined.

  5. Methods for data reduction and loads analysis of Space Shuttle Solid Rocket Booster model water impact tests

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The methodology used to predict full scale space shuttle solid rocket booster (SRB) water impact loads from scale model test data is described. Tests conducted included 12.5 inch and 120 inch diameter models of the SRB. Geometry and mass characteristics of the models were varied in each test series to reflect the current SRB baseline configuration. Nose first and tail first water entry modes were investigated with full-scale initial impact vertical velocities of 40 to 120 ft/sec, horizontal velocities of 0 to 60 ft/sec., and off-vertical angles of 0 to plus or minus 30 degrees. The test program included a series of tests with scaled atmospheric pressure.

  6. Implantation of Thickened Artificial Bone for Reduction of Dead Space and Prevention of Infection Between Implant and Dura in Secondary Reconstruction of the Skull.

    PubMed

    Ozaki, Mine; Narita, Keigo; Kurita, Masakazu; Iwashina, Yuki; Takushima, Akihiko; Harii, Kiyonori

    2017-02-15

    For the treatment of skull defect compensation after neurosurgery, a customized artificial bone is often employed owing to its toughness and the relative ease of producing cosmetically good result. However, implants are vulnerable to infection and removal of implant is sometimes necessary. Several other treatment options such as autologous bone graft or free flap are likely to be considered for the secondary reconstruction to avoid reinfection; however, reimplantation of artificial bone is beneficial for the patients, being not concerned with donor site morbidity. The authors consider one of risk factors of infection of artificial bone as dead space between the implant and dura. To attain reduction of the dead space, we have employed thickened artificial bone.Between 2010 and 2014, 6 patients underwent implantation of thickened artificial bone for the secondary reconstruction.First, the infected artificial material was removed with proper debridement. More than 3 months after the closure of the infected wound, tissue expander was inserted beneath the surrounding scalp to ensure the coverage of subsequently implanted artificial bone without skin tension. The thickened artificial bone was designed from the computed tomography findings so as not to leave any dead space between the implant and dura. After optimal expansion of the scalp, the artificial bone was implanted.Postoperative courses were uneventful and the appearance of the cranial vault was satisfactory in all patients.The authors consider the use of the thickened artificial bone is easier and more suitable for patients having a skull defect, particularly in secondary reconstruction.

  7. Significant reduction in energy for plant-growth lighting in space using targeted LED lighting and spectral manipulation

    NASA Astrophysics Data System (ADS)

    Poulet, L.; Massa, G. D.; Morrow, R. C.; Bourget, C. M.; Wheeler, R. M.; Mitchell, C. A.

    2014-07-01

    Bioregenerative life-support systems involving photoautotrophic organisms will be necessary to sustain long-duration crewed missions at distant space destinations. Since sufficient sunlight will not always be available for plant growth at many space destinations, efficient electric-lighting solutions are greatly needed. The present study demonstrated that targeted plant lighting with light-emitting diodes (LEDs) and optimizing spectral parameters for close-canopy overhead LED lighting allowed the model crop leaf lettuce (Lactuca sativa L. cv. 'Waldmann's Green') to be grown using significantly less electrical energy than using traditional electric-lighting sources. Lettuce stands were grown hydroponically in a growth chamber controlling temperature, relative humidity, and CO2 level. Several red:blue ratios were tested for growth rate during the lag phase of lettuce growth. In addition, start of the exponential growth phase was evaluated. Following establishment of a 95% red + 5% blue spectral balance giving the best growth response, the energy efficiency of a targeted lighting system was compared with that of two total coverage (untargeted) LED lighting systems throughout a crop-production cycle, one using the same proportion of red and blue LEDs and the other using white LEDs. At the end of each cropping cycle, whole-plant fresh and dry mass and leaf area were measured and correlated with the amount of electrical energy (kWh) consumed for crop lighting. Lettuce crops grown with targeted red + blue LED lighting used 50% less energy per unit dry biomass accumulated, and the total coverage white LEDs used 32% less energy per unit dry biomass accumulated than did the total coverage red + blue LEDs. An energy-conversion efficiency of less than 1 kWh/g dry biomass is possible using targeted close-canopy LED lighting with spectral optimization. This project was supported by NASA grant NNX09AL99G.

  8. CARBON DIOXIDE REDUCTION SYSTEM.

    DTIC Science & Technology

    CARBON DIOXIDE , *SPACE FLIGHT, RESPIRATION, REDUCTION(CHEMISTRY), RESPIRATION, AEROSPACE MEDICINE, ELECTROLYSIS, INSTRUMENTATION, ELECTROLYTES, VOLTAGE, MANNED, YTTRIUM COMPOUNDS, ZIRCONIUM COMPOUNDS, NICKEL.

  9. Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 6: Primary nozzle diffuser analysis

    NASA Technical Reports Server (NTRS)

    Foley, Michael J.

    1989-01-01

    The primary nozzle diffuser routes fuel from the main fuel valve on the Space Shuttle Main Engine (SSME) to the nozzle coolant inlet mainfold, main combustion chamber coolant inlet mainfold, chamber coolant valve, and the augmented spark igniters. The diffuser also includes the fuel system purge check valve connection. A static stress analysis was performed on the diffuser because no detailed analysis was done on this part in the past. Structural concerns were in the area of the welds because approximately 10 percent are in areas inaccessible by X-ray testing devices. Flow dynamics and thermodynamics were not included in the analysis load case. Constant internal pressure at maximum SSME power was used instead. A three-dimensional, finite element method was generated using ANSYS version 4.3A on the Lockheed VAX 11/785 computer to perform the stress computations. IDEAS Supertab on a Sun 3/60 computer was used to create the finite element model. Rocketdyne drawing number RS009156 was used for the model interpretation. The flight diffuser is denoted as -101. A description of the model, boundary conditions/load case, material properties, structural analysis/results, and a summary are included for documentation.

  10. OAST Space Theme Workshop. Volume 2: Theme summary. 3: Search for extraterrestrial intelligence (no. 9). A: Theme statement. B. 26 April 1976 presentation. C. Summary. D. Newer initiatives (form 4). E. Initiative actions (form 5)

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Preliminary (1977-1983), intermediate (1982-1988), and long term (1989+) phases of the search for extraterrestrial intelligence (SETI) program are examined as well as the benefits to be derived in radioastronomy and the problems to be surmounted in radio frequency interference. The priorities, intrinsic value, criteria, and strategy for the search are discussed for both terrestrial and lunar-based CYCLOPS and for a space SETI system located at lunar liberation point L4. New initiatives related to antenna independent technology, multichannel analyzers, and radio frequency interference shielding are listed. Projected SETI program costs are included.

  11. Search Cloud

    MedlinePlus

    ... this page: https://medlineplus.gov/cloud.html Search Cloud To use the sharing features on this page, ... chest pa and lateral Share the MedlinePlus search cloud with your users by embedding our search cloud ...

  12. Structure determination of symmetric homo-oligomers by a complete search of symmetry configuration space, using NMR restraints and van der Waals packing.

    PubMed

    Potluri, Shobha; Yan, Anthony K; Chou, James J; Donald, Bruce R; Bailey-Kellogg, Chris

    2006-10-01

    Structural studies of symmetric homo-oligomers provide mechanistic insights into their roles in essential biological processes, including cell signaling and cellular regulation. This paper presents a novel algorithm for homo-oligomeric structure determination, given the subunit structure, that is both complete, in that it evaluates all possible conformations, and data-driven, in that it evaluates conformations separately for consistency with experimental data and for quality of packing. Completeness ensures that the algorithm does not miss the native conformation, and being data-driven enables it to assess the structural precision possible from data alone. Our algorithm performs a branch-and-bound search in the symmetry configuration space, the space of symmetry axis parameters (positions and orientations) defining all possible C(n) homo-oligomeric complexes for a given subunit structure. It eliminates those symmetry axes inconsistent with intersubunit nuclear Overhauser effect (NOE) distance restraints and then identifies conformations representing any consistent, well-packed structure to within a user-defined similarity level. For the human phospholamban pentamer in dodecylphosphocholine micelles, using the structure of one subunit determined from a subset of the experimental NMR data, our algorithm identifies a diverse set of complex structures consistent with the nine intersubunit NOE restraints. The distribution of determined structures provides an objective characterization of structural uncertainty: backbone RMSD to the previously determined structure ranges from 1.07 to 8.85 A, and variance in backbone atomic coordinates is an average of 12.32 A(2). Incorporating vdW packing reduces structural diversity to a maximum backbone RMSD of 6.24 A and an average backbone variance of 6.80 A(2). By comparing data consistency and packing quality under different assumptions of oligomeric number, our algorithm identifies the pentamer as the most likely oligomeric state

  13. Problems of molecular design and the computer. XII. A computer search for possible intermediates in the reduction of 2-vinyl-1,1-bis(bromomethyl)cyclopropane using the FLAMINGO program system

    SciTech Connect

    Zefirov, N.S.; Gordeeva, E.V.; Kuznetsova, T.S.; Kozhushkov, S.I.

    1988-06-10

    A description has been given for the previously developed FLAMINGO computer system for the prediction of the mechanisms of complex organic reactions in the case of the reduction of 2-vinyl-1,1-bis(bromomethyl)cyclopropane. The operation of the program and the criteria for sorting the results generated by the computer were given. Operation of the program gave the structures of all possible intermediates and reaction products taking account of previously indicated limitations. All the computer predictions of the transformations were analyzed from the viewpoint of the chemistry of this reaction. The results of the computer search indicated the mixed anionic and radical mechanism of this reaction and gave the possible pathways for the formation of each compound obtained in an experimental study of this reaction.

  14. Talent Searches.

    ERIC Educational Resources Information Center

    Silverman, Linda Kreger, Ed.

    1994-01-01

    Talent searches are discussed in this journal theme issue, with two feature articles and several recurring columns. "Talent Search: A Driving Force in Gifted Education," by Paula Olszewski-Kubilius, defines what a talent search is, how the Talent Search was developed by Dr. Julian Stanley at Johns Hopkins University in Maryland, the…

  15. Proposed new concepts for an advanced search and rescue satellite system

    NASA Technical Reports Server (NTRS)

    Hembree, W. A.; Wallace, R.; Kaminsky, Y.

    1985-01-01

    Methods of reducing the forwarding time from COSPAS/SARSAT (Space System for Search of Distressed Vessels/Search and Rescue Satellite-Aided Tracking System) satellite passage until a location is supplied to the search and rescue (SAR) forces are studied. It is shown how supplemental use of geostationary satellites or institution off-polar ground stations can reduce the time delay from 62 min to 7 min. The tradeoff between the two approaches is their cost and complexity versus time delay reduction. Sample systems are developed here in order to examine the tradeoffs.

  16. Comparing State-Space Multivariable Controls to Multi-SISO Controls for Load Reduction of Drivetrain-Coupled Modes on Wind Turbines through Field-Testing: Preprint

    SciTech Connect

    Fleming, P. A.; van Wingerden, J. W.; Wright, A. D.

    2011-12-01

    This paper presents the structure of an ongoing controller comparison experiment at NREL's National Wind Technology Center; the design process for the two controllers compared in this phase of the experiment, and initial comparison results obtained in field-testing. The intention of the study is to demonstrate the advantage of using modern multivariable methods for designing control systems for wind turbines versus conventional approaches. We will demonstrate the advantages through field-test results from experimental turbines located at the NWTC. At least two controllers are being developed side-by-side to meet an incrementally increasing number of turbine load-reduction objectives. The first, a multiple single-input, single-output (m-SISO) approach, uses separately developed decoupled and classicially tuned controllers, which is, to the best of our knowledge, common practice in the wind industry. The remaining controllers are developed using state-space multiple-input and multiple-output (MIMO) techniques to explicity account for coupling between loops and to optimize given known frequency structures of the turbine and disturbance. In this first publication from the study, we present the structure of the ongoing controller comparison experiment, the design process for the two controllers compared in this phase, and initial comparison results obtained in field-testing.

  17. Comparing State-Space Multivariable Controls to Multi-SISO Controls for Load Reduction of Drivetrain-Coupled Modes on Wind Turbines Through Field-Testing

    SciTech Connect

    Fleming, P. A.; Van Wingerden, J. W.; Wright, A. D.

    2012-01-01

    In this paper we present results from an ongoing controller comparison study at the National Renewable Energy Laboratory's (NREL's) National Wind Technology Center (NWTC). The intention of the study is to demonstrate the advantage of using modern multivariable methods for designing control systems for wind turbines versus conventional approaches. We will demonstrate the advantages through field-test results from experimental turbines located at the NWTC. At least two controllers are being developed side-by-side to meet an incrementally increasing number of turbine load-reduction objectives. The first, a multiple single-input, single-output (m-SISO) approach, uses separately developed decoupled and classicially tuned controllers, which is, to the best of our knowledge, common practice in the wind industry. The remaining controllers are developed using state-space multiple-input and multiple-output (MIMO) techniques to explicity account for coupling between loops and to optimize given known frequency structures of the turbine and disturbance. In this first publication from the study, we present the structure of the ongoing controller comparison experiment, the design process for the two controllers compared in this phase, and initial comparison results obtained in field-testing.

  18. Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 7: High pressure fuel turbo-pump third stage impeller analysis

    NASA Technical Reports Server (NTRS)

    Pool, Kirby V.

    1989-01-01

    This volume summarizes the analysis used to assess the structural life of the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbo-Pump (HPFTP) Third Stage Impeller. This analysis was performed in three phases, all using the DIAL finite element code. The first phase was a static stress analysis to determine the mean (non-varying) stress and static margin of safety for the part. The loads involved were steady state pressure and centrifugal force due to spinning. The second phase of the analysis was a modal survey to determine the vibrational modes and natural frequencies of the impeller. The third phase was a dynamic response analysis to determine the alternating component of the stress due to time varying pressure impulses at the outlet (diffuser) side of the impeller. The results of the three phases of the analysis show that the Third Stage Impeller operates very near the upper limits of its capability at full power level (FPL) loading. The static loading alone creates stresses in some areas of the shroud which exceed the yield point of the material. Additional cyclic loading due to the dynamic force could lead to a significant reduction in the life of this part. The cyclic stresses determined in the dynamic response phase of this study are based on an assumption regarding the magnitude of the forcing function.

  19. The Search for Exomoons

    NASA Astrophysics Data System (ADS)

    Kipping, D. M.

    2011-12-01

    With exoplanet detections becoming routine, astronomers are now vying to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process will undoubtedly involve the search for extrasolar moons. In this work, we explore the motivations for searching for exomoons, review some of the previously proposed detection techniques and finally introduce transit duration variation (TDV) as a proposed search method. We find that these techniques could easily detect Earth-mass exomoons with current instruments and potentially down to Galilean mass moons with future space missions like Kepler.

  20. The generalised k-Truncated Suffix Tree for time-and space-efficient searches in multiple DNA or protein sequences.

    PubMed

    Schulz, Marcel H; Bauer, Sebastian; Robinson, Peter N

    2008-01-01

    Efficient searching for specific subsequences in a set of longer sequences is an important component of many bioinformatics algorithms. Generalised suffix trees and suffix arrays allow searches for a pattern of length n in time proportional to n independent of the length of the sequences, and are thus attractive for a variety of applications. Here, we present an algorithm termed the generalised k-Truncated Suffix Tree (kTST), that represents an adaption of Ukkonen's linear-time suffix tree construction algorithm. The kTST algorithm creates a k-deep tree in linear time that allows rapid searches for short patterns of length of up to k characters. The kTST can offer advantages in computational time and memory usage for searches for short sequences in DNA or protein sequences compared to other suffix-based algorithms.

  1. A linguistic geometry for space applications

    NASA Technical Reports Server (NTRS)

    Stilman, Boris

    1994-01-01

    We develop a formal theory, the so-called Linguistic Geometry, in order to discover the inner properties of human expert heuristics, which were successful in a certain class of complex control systems, and apply them to different systems. This research relies on the formalization of search heuristics of high-skilled human experts which allow for the decomposition of complex system into the hierarchy of subsystems, and thus solve intractable problems reducing the search. The hierarchy of subsystems is represented as a hierarchy of formal attribute languages. This paper includes a formal survey of the Linguistic Geometry, and new example of a solution of optimization problem for the space robotic vehicles. This example includes actual generation of the hierarchy of languages, some details of trajectory generation and demonstrates the drastic reduction of search in comparison with conventional search algorithms.

  2. Confidential Searches.

    ERIC Educational Resources Information Center

    Kenney, Linda Chion

    2003-01-01

    Will the stealth superintendent hunt in Cincinnati become tomorrow's standard approach? Search consultants and superintendents offer their views on how far confidentiality should go. Also includes a search firm's process for shielding identities and a confidentiality pledge. (MLF)

  3. Suspicionless Searches.

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2000-01-01

    In a federal case involving a vice-principal's pat-down search of middle-school students in a cafeteria (for a missing pizza knife), the court upheld the search, saying it was relatively unintrusive and met "TLO's" reasonable-suspicion standards. Principals need reasonable justification for searching a group. (Contains 18 references.)…

  4. BCI Control of Heuristic Search Algorithms

    PubMed Central

    Cavazza, Marc; Aranyi, Gabor; Charles, Fred

    2017-01-01

    The ability to develop Brain-Computer Interfaces (BCI) to Intelligent Systems would offer new perspectives in terms of human supervision of complex Artificial Intelligence (AI) systems, as well as supporting new types of applications. In this article, we introduce a basic mechanism for the control of heuristic search through fNIRS-based BCI. The rationale is that heuristic search is not only a basic AI mechanism but also one still at the heart of many different AI systems. We investigate how users’ mental disposition can be harnessed to influence the performance of heuristic search algorithm through a mechanism of precision-complexity exchange. From a system perspective, we use weighted variants of the A* algorithm which have an ability to provide faster, albeit suboptimal solutions. We use recent results in affective BCI to capture a BCI signal, which is indicative of a compatible mental disposition in the user. It has been established that Prefrontal Cortex (PFC) asymmetry is strongly correlated to motivational dispositions and results anticipation, such as approach or even risk-taking, and that this asymmetry is amenable to Neurofeedback (NF) control. Since PFC asymmetry is accessible through fNIRS, we designed a BCI paradigm in which users vary their PFC asymmetry through NF during heuristic search tasks, resulting in faster solutions. This is achieved through mapping the PFC asymmetry value onto the dynamic weighting parameter of the weighted A* (WA*) algorithm. We illustrate this approach through two different experiments, one based on solving 8-puzzle configurations, and the other on path planning. In both experiments, subjects were able to speed up the computation of a solution through a reduction of search space in WA*. Our results establish the ability of subjects to intervene in heuristic search progression, with effects which are commensurate to their control of PFC asymmetry: this opens the way to new mechanisms for the implementation of hybrid

  5. BCI Control of Heuristic Search Algorithms.

    PubMed

    Cavazza, Marc; Aranyi, Gabor; Charles, Fred

    2017-01-01

    The ability to develop Brain-Computer Interfaces (BCI) to Intelligent Systems would offer new perspectives in terms of human supervision of complex Artificial Intelligence (AI) systems, as well as supporting new types of applications. In this article, we introduce a basic mechanism for the control of heuristic search through fNIRS-based BCI. The rationale is that heuristic search is not only a basic AI mechanism but also one still at the heart of many different AI systems. We investigate how users' mental disposition can be harnessed to influence the performance of heuristic search algorithm through a mechanism of precision-complexity exchange. From a system perspective, we use weighted variants of the A* algorithm which have an ability to provide faster, albeit suboptimal solutions. We use recent results in affective BCI to capture a BCI signal, which is indicative of a compatible mental disposition in the user. It has been established that Prefrontal Cortex (PFC) asymmetry is strongly correlated to motivational dispositions and results anticipation, such as approach or even risk-taking, and that this asymmetry is amenable to Neurofeedback (NF) control. Since PFC asymmetry is accessible through fNIRS, we designed a BCI paradigm in which users vary their PFC asymmetry through NF during heuristic search tasks, resulting in faster solutions. This is achieved through mapping the PFC asymmetry value onto the dynamic weighting parameter of the weighted A* (WA*) algorithm. We illustrate this approach through two different experiments, one based on solving 8-puzzle configurations, and the other on path planning. In both experiments, subjects were able to speed up the computation of a solution through a reduction of search space in WA*. Our results establish the ability of subjects to intervene in heuristic search progression, with effects which are commensurate to their control of PFC asymmetry: this opens the way to new mechanisms for the implementation of hybrid

  6. Workers Search for Columbia's Debris

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Members of a US Forest Service search team walk a grid during a Columbia recovery search near the Hemphill, Texas site. The group is accompanied by a space program worker able to identify potential hazards of Shuttle parts. Workers from every NASA Center and numerous federal, state, and local agencies searched for Columbia's debris in the recovery effort. For more information on STS-107, please see GRIN Columbia General Explanation

  7. Foraging search: Prototypical intelligence

    NASA Astrophysics Data System (ADS)

    Mobus, George

    2000-05-01

    We think because we eat. Or as Descartes might have said, on a little more reflection, "I need to eat, therefore I think." Animals that forage for a living repeatedly face the problem of searching for a sparsely distributed resource in a vast space. Furthermore, the resource may occur sporadically and episodically under conditions of true uncertainty (nonstationary, complex and non-linear dynamics). I assert that this problem is the canonical problem solved by intelligence. It's solution is the basis for the evolution of more advanced intelligence in which the space of search includes that of concepts (objects and relations) encoded in cortical structures. In humans the conscious experience of searching through concept space we call thinking. The foraging search model is based upon a higher-order autopoeitic system (the forager) employing anticipatory processing to enhance its success at finding food while avoiding becoming food or having accidents in a hostile world. I present a semi-formal description of the general foraging search problem and an approach to its solution. The latter is a brain-like structure employing dynamically adaptive neurons. A physical robot, MAVRIC, embodies some principles of foraging. It learns cues that lead to improvements in finding targets in a dynamic and nonstationary environment. This capability is based on a unique learning mechanism that encodes causal relations in the neural-like processing element. An argument is advanced that searching for resources in the physical world, as per the foraging model, is a prototype for generalized search for conceptual resources as when we think. A problem represents a conceptual disturbance in a homeostatic sense. The finding of a solution restores the homeostatic balance. The establishment of links between conceptual cues and solutions (resources) and the later use of those cues to think through to solutions of quasi-isomorphic problems is, essentially, foraging for ideas. It is a quite

  8. A search for Earth-crossing asteroids, supplement

    NASA Technical Reports Server (NTRS)

    Taff, L. G.; Sorvari, J. M.; Kostishack, D. F.

    1984-01-01

    The ground based electro-optical deep space surveillance program involves a network of computer controlled 40 inch 1m telescopes equipped with large format, low light level, television cameras of the intensified silicon diode array type which is to replace the Baker-Nunn photographic camera system for artificial satellite tracking. A prototype observatory was constructed where distant artificial satellites are discriminated from stars in real time on the basis of the satellites' proper motion. Hardware was modified and the technique was used to observe and search for minor planets. Asteroids are now routinely observed and searched. The complete observing cycle, including the 2"-3" measurement of position, requires about four minutes at present. The commonality of asteroids and artificial satellite observing, searching, data reduction, and orbital analysis is stressed. Improvements to the hardware and software as well as operational techniques are considered.

  9. Semantic Search of Web Services

    ERIC Educational Resources Information Center

    Hao, Ke

    2013-01-01

    This dissertation addresses semantic search of Web services using natural language processing. We first survey various existing approaches, focusing on the fact that the expensive costs of current semantic annotation frameworks result in limited use of semantic search for large scale applications. We then propose a vector space model based service…

  10. DNA breakage drives nuclear search.

    PubMed

    Ira, Grzegorz; Hastings, Philip J

    2012-05-02

    The search for a homologous template is a fundamental, yet largely uncharacterized, reaction in DNA double-strand break repair. Two reports now demonstrate that broken chromosomes increase their movement and explore large volumes of nuclear space searching for a homologous template. Break mobility requires resection and recombination enzymes, as well as damage-checkpoint components.

  11. Organic chemistry in space

    NASA Technical Reports Server (NTRS)

    Johnson, R. D.

    1977-01-01

    Organic cosmochemistry, organic materials in space exploration, and biochemistry of man in space are briefly surveyed. A model of Jupiter's atmosphere is considered, and the search for organic molecules in the solar system and in interstellar space is discussed. Materials and analytical techniques relevant to space exploration are indicated, and the blood and urine analyses performed on Skylab are described.

  12. Optimal design of compact spur gear reductions

    NASA Technical Reports Server (NTRS)

    Savage, M.; Lattime, S. B.; Kimmel, J. A.; Coe, H. H.

    1992-01-01

    The optimal design of compact spur gear reductions includes the selection of bearing and shaft proportions in addition to gear mesh parameters. Designs for single mesh spur gear reductions are based on optimization of system life, system volume, and system weight including gears, support shafts, and the four bearings. The overall optimization allows component properties to interact, yielding the best composite design. A modified feasible directions search algorithm directs the optimization through a continuous design space. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for optimization. After finding the continuous optimum, the designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearings on the optimal configurations.

  13. Are major reductions in new HIV infections possible with people who inject drugs? The case for low dead-space syringes in highly affected countries.

    PubMed

    Zule, William A; Cross, Harry E; Stover, John; Pretorius, Carel

    2013-01-01

    Circumstantial evidence from laboratory studies, mathematical models, ecological studies and bio behavioural surveys, suggests that injection-related HIV epidemics may be averted or reversed if people who inject drugs (PWID) switch from using high dead-space to using low dead-space syringes. In laboratory experiments that simulated the injection process and rinsing with water, low dead space syringes retained 1000 times less blood than high dead space syringes. In mathematical models, switching PWID from high dead space to low dead space syringes prevents or reverses injection-related HIV epidemics. No one knows if such an intervention is feasible or what effect it would have on HIV transmission among PWID. Feasibility studies and randomized controlled trials (RCTs) will be needed to answer these questions definitively, but these studies will be very expensive and take years to complete. Rather than waiting for them to be completed, we argue for an approach similar to that used with needle and syringe programs (NSP), which were promoted and implemented before being tested more rigorously. Before implementation, rapid assessments that involve PWID will need to be conducted to ensure buy-in from PWID and other local stakeholders. This commentary summarizes the existing evidence regarding the protective effects of low dead space syringes and estimates potential impacts on HIV transmission; it describes potential barriers to transitioning PWID from high dead space to low dead space needles and syringes; and it presents strategies for overcoming these barriers.

  14. Power Search.

    ERIC Educational Resources Information Center

    Haskin, David

    1997-01-01

    Compares six leading Web search engines (AltaVista, Excite, HotBot, Infoseek, Lycos, and Northern Light), looking at the breadth of their coverage, accuracy, and ease of use, and finds a clear favorite of the six. Includes tips that can improve search results. (AEF)

  15. Double shrinking sparse dimension reduction.

    PubMed

    Zhou, Tianyi; Tao, Dacheng

    2013-01-01

    Learning tasks such as classification and clustering usually perform better and cost less (time and space) on compressed representations than on the original data. Previous works mainly compress data via dimension reduction. In this paper, we propose "double shrinking" to compress image data on both dimensionality and cardinality via building either sparse low-dimensional representations or a sparse projection matrix for dimension reduction. We formulate a double shrinking model (DSM) as an l(1) regularized variance maximization with constraint ||x||(2)=1, and develop a double shrinking algorithm (DSA) to optimize DSM. DSA is a path-following algorithm that can build the whole solution path of locally optimal solutions of different sparse levels. Each solution on the path is a "warm start" for searching the next sparser one. In each iteration of DSA, the direction, the step size, and the Lagrangian multiplier are deduced from the Karush-Kuhn-Tucker conditions. The magnitudes of trivial variables are shrunk and the importances of critical variables are simultaneously augmented along the selected direction with the determined step length. Double shrinking can be applied to manifold learning and feature selections for better interpretation of features, and can be combined with classification and clustering to boost their performance. The experimental results suggest that double shrinking produces efficient and effective data compression.

  16. [Development of domain specific search engines].

    PubMed

    Takai, T; Tokunaga, M; Maeda, K; Kaminuma, T

    2000-01-01

    As cyber space exploding in a pace that nobody has ever imagined, it becomes very important to search cyber space efficiently and effectively. One solution to this problem is search engines. Already a lot of commercial search engines have been put on the market. However these search engines respond with such cumbersome results that domain specific experts can not tolerate. Using a dedicate hardware and a commercial software called OpenText, we have tried to develop several domain specific search engines. These engines are for our institute's Web contents, drugs, chemical safety, endocrine disruptors, and emergent response for chemical hazard. These engines have been on our Web site for testing.

  17. HUNTER-GATHERER: Three search techniques integrated for natural language semantics

    SciTech Connect

    Beale, S.; Nirenburg, S.; Mahesh, K.

    1996-12-31

    This work integrates three related Al search techniques - constraint satisfaction, branch-and-bound and solution synthesis - and applies the result to semantic processing in natural language (NL). We summarize the approach as {open_quote}Hunter-Gatherer:{close_quotes} (1) branch-and-bound and constraint satisfaction allow us to {open_quote}hunt down{close_quotes} non-optimal and impossible solutions and prune them from the search space. (2) solution synthesis methods then {open_quote}gather{close_quotes} all optimal solutions avoiding exponential complexity. Each of the three techniques is briefly described, as well as their extensions and combinations used in our system. We focus on the combination of solution synthesis and branch-and-bound methods which has enabled near-linear-time processing in our applications. Finally, we illustrate how the use of our technique in a large-scale MT project allowed a drastic reduction in search space.

  18. Extraterrestrial intelligence? The search is on

    NASA Technical Reports Server (NTRS)

    Coulter, Gary R.

    1991-01-01

    NASA's SETI-Microwave Observing Project, beginning on October 12, 1992, will search the closest solar-type stars for radio signals from extraterrestrial civilizations. When completed in the year 2000, the NASA search will have surpassed the search volume of all prior searches by a factor of 10 exp 10. The world's largest radio telescopes will be employed, in conjunction with the NASA Deep Space Network communications antennas. The program will be led by NASA-Ames, with substantial contribution by JPL.

  19. Analysis of latent variance reduction methods in phase space Monte Carlo calculations for 6, 10 and 18 MV photons by using MCNP code

    NASA Astrophysics Data System (ADS)

    Ezzati, A. O.; Sohrabpour, M.

    2013-02-01

    In this study, azimuthal particle redistribution (APR), and azimuthal particle rotational splitting (APRS) methods are implemented in MCNPX2.4 source code. First of all, the efficiency of these methods was compared to two tallying methods. The APRS is more efficient than the APR method in track length estimator tallies. However in the energy deposition tally, both methods have nearly the same efficiency. Latent variance reduction factors were obtained for 6, 10 and 18 MV photons as well. The APRS relative efficiency contours were obtained. These obtained contours reveal that by increasing the photon energies, the contours depth and the surrounding areas were further increased. The relative efficiency contours indicated that the variance reduction factor is position and energy dependent. The out of field voxels relative efficiency contours showed that latent variance reduction methods increased the Monte Carlo (MC) simulation efficiency in the out of field voxels. The APR and APRS average variance reduction factors had differences less than 0.6% for splitting number of 1000.

  20. Searching with the Google Search Appliance (GSA)

    EPA Pesticide Factsheets

    Guidance and search help resource listing examples of common queries that can be used in the Google Search Appliance search request, including examples of special characters, or query term seperators that Google Search Appliance recognizes.

  1. Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 3B: High pressure fuel turbo-pump preburner pump bearing assembly analysis

    NASA Technical Reports Server (NTRS)

    Power, Gloria B.; Violett, Rebeca S.

    1989-01-01

    The analysis performed on the High Pressure Oxidizer Turbopump (HPOTP) preburner pump bearing assembly located on the Space Shuttle Main Engine (SSME) is summarized. An ANSYS finite element model for the inlet assembly was built and executed. Thermal and static analyses were performed.

  2. Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 4: High pressure fuel turbo-pump inlet housing analysis

    NASA Technical Reports Server (NTRS)

    Pool, Kirby V.

    1989-01-01

    The analysis performed on the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) inlet housings is summarized. Three DIAL finite element models were build to aid in assessing the structural life of the welds and fillets at the vanes. Complete results are given.

  3. Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 3A: High pressure oxidizer turbo-pump preburner pump housing stress analysis report

    NASA Technical Reports Server (NTRS)

    Shannon, Robert V., Jr.

    1989-01-01

    The model generation and structural analysis performed for the High Pressure Oxidizer Turbopump (HPOTP) preburner pump volute housing located on the main pump end of the HPOTP in the space shuttle main engine are summarized. An ANSYS finite element model of the volute housing was built and executed. A static structural analysis was performed on the Engineering Analysis and Data System (EADS) Cray-XMP supercomputer

  4. In search of the best match: probing a multi-dimensional cloud microphysical parameter space to better understand what controls cloud thermodynamic phase

    NASA Astrophysics Data System (ADS)

    Tan, Ivy; Storelvmo, Trude

    2015-04-01

    Substantial improvements have been made to the cloud microphysical schemes used in the latest generation of global climate models (GCMs), however, an outstanding weakness of these schemes lies in the arbitrariness of their tuning parameters, which are also notoriously fraught with uncertainties. Despite the growing effort in improving the cloud microphysical schemes in GCMs, most of this effort has neglected to focus on improving the ability of GCMs to accurately simulate the present-day global distribution of thermodynamic phase partitioning in mixed-phase clouds. Liquid droplets and ice crystals not only influence the Earth's radiative budget and hence climate sensitivity via their contrasting optical properties, but also through the effects of their lifetimes in the atmosphere. The current study employs NCAR's CAM5.1, and uses observations of cloud phase obtained by NASA's CALIOP lidar over a 79-month period (November 2007 to June 2014) guide the accurate simulation of the global distribution of mixed-phase clouds in 20∘ latitudinal bands at the -10∘ C, -20∘C and -30∘C isotherms, by adjusting six relevant cloud microphysical tuning parameters in the CAM5.1 via Quasi-Monte Carlo sampling. Among the parameters include those that control the Wegener-Bergeron-Findeisen (WBF) timescale for the conversion of supercooled liquid droplets to ice and snow in mixed-phase clouds, the fraction of ice nuclei that nucleate ice in the atmosphere, ice crystal sedimentation speed, and wet scavenging in stratiform and convective clouds. Using a Generalized Linear Model as a variance-based sensitivity analysis, the relative contributions of each of the six parameters are quantified to gain a better understanding of the importance of their individual and two-way interaction effects on the liquid to ice proportion in mixed-phase clouds. Thus, the methodology implemented in the current study aims to search for the combination of cloud microphysical parameters in a GCM that

  5. Space Launch System (SLS) Program Overview NASA Research Announcement (NRA) Advanced Booster (AB) Engineering Demonstration and Risk Reduction (EDRR) Industry Day

    NASA Technical Reports Server (NTRS)

    May, Todd A.

    2011-01-01

    SLS is a national capability that empowers entirely new exploration for missions of national importance. Program key tenets are safety, affordability, and sustainability. SLS builds on a solid foundation of experience and current capacities to enable a timely initial capability and evolve to a flexible heavy-lift capability through competitive opportunities: (1) Reduce risks leading to an affordable Advanced Booster that meets the evolved capabilities of SLS (2) Enable competition by mitigating targeted Advanced Booster risks to enhance SLS affordability and performance The road ahead promises to be an exciting journey for present and future generations, and we look forward to working with you to continue America fs space exploration.

  6. Analytical trade study of the STS payload environment. [design analysis and cost estimates for noise reduction devices for space shuttle orbiter payloads

    NASA Technical Reports Server (NTRS)

    Rader, W. P.; Barrett, S.; Raratono, J.; Payne, K. R.

    1976-01-01

    The current predicted acoustic environment for the shuttle orbiter payload bay will produce random vibration environments for payload components and subsystems which potentially will result in design, weight and cost penalties if means of protecting the payloads are not developed. Results are presented of a study to develop, through design and cost effectiveness trade studies, conceptual noise suppression device designs for space shuttle payloads. The impact of noise suppression on environmental levels and associated test costs, and on test philosophy for the various payload classes is considered with the ultimate goal of reducing payload test costs. Conclusions and recommendations are presented.

  7. Cost reduction in space operations - Structuring a planetary program to minimize the annual funding requirement as opposed to minimizing the program runout cost

    NASA Technical Reports Server (NTRS)

    Herman, D. H.; Niehoff, J. C.; Spadoni, D. J.

    1980-01-01

    An approach is proposed for the structuring of a planetary mission set wherein the peak annual funding is minimized to meet the annual budget restraint. One aspect of the approach is to have a transportation capability that can launch a mission in any planetary opportunity; such capability can be provided by solar electric propulsion. Another cost reduction technique is to structure a mission test in a time sequenced fashion that could utilize essentially the same spacecraft for the implementation of several missions. A third technique would be to fulfill a scientific objective in several sequential missions rather than attempt to accomplish all of the objectives with one mission. The application of the approach is illustrated by an example involving the Solar Orbiter Dual Probe mission.

  8. An investigation of drag reduction fairings on the space shuttle vehicle 5 configuration (model 74-OTS) in the MSFC 14 inch trisonic wind tunnel (FA14)

    NASA Technical Reports Server (NTRS)

    Ramsey, P. E.

    1976-01-01

    An experimental investigation was conducted in the MSFC 14-inch TWT (FA14, TWT 600) to determine the static stability and drag on a 0.004 scale model of the shuttle ascent configuration. The primary objective was to study the possibility of reducing the launch vehicle drag by using Orbiter/ET/SRB fairings, streamlined orbiter fore and aft attach structures, SRB and ET alternative nose configurations, and devices for modifying the flow between the orbiter and ET. The secondary objective was to determine the longitudinal and directional characteristics of the ascent configuration with the most promising of the drag reduction devices installed. Data were obtained for a Mach number range of 0.6 through 4.96 and angles of attack from -5 through 5 degrees at zero degrees side slip angle.

  9. An adaptive random search for short term generation scheduling with network constraints

    PubMed Central

    Velasco, Jonás; Selley, Héctor J.

    2017-01-01

    This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach. PMID:28234954

  10. An adaptive random search for short term generation scheduling with network constraints.

    PubMed

    Marmolejo, J A; Velasco, Jonás; Selley, Héctor J

    2017-01-01

    This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach.

  11. The quest for complex molecules in space: laboratory spectroscopy of n-butyl cyanide, n-C4H9CN, in the millimeter wave region and its astronomical search in Sagittarius B2(N)

    NASA Astrophysics Data System (ADS)

    Ordu, M. H.; Müller, H. S. P.; Walters, A.; Nuñez, M.; Lewen, F.; Belloche, A.; Menten, K. M.; Schlemmer, S.

    2012-05-01

    Context. The saturated n-propyl cyanide was recently detected in Sagittarius B2(N). The next largest unbranched alkyl cyanide is n-butyl cyanide. Aims: We provide accurate rest frequency predictions beyond the millimeter wave range to search for this molecule in the Galactic center source Sagittarius B2(N) and facilitate its detection in space. Methods: We investigated the laboratory rotational spectrum of n-butyl cyanide between 75 GHz and 348 GHz. We searched for emission lines produced by the molecule in our sensitive IRAM 30 m molecular line survey of Sagittarius B2(N). Results: We identified more than one thousand rotational transitions in the laboratory for each of the three conformers for which limited data had been obtained previously in a molecular beam microwave study. The quantum number range was greatly extended to J ≈ 120 or more and Ka > 35, resulting in accurate spectroscopic parameters and accurate rest frequency calculations up to about 500 GHz for strong to moderately weak transitions of the two lower energy conformers. Upper limits to the column densities of N ≤ 3 × 1015 cm-2 and 8 × 1015 cm-2 were derived towards Sagittarius B2(N) for the two lower energy conformers, anti-anti and gauche-anti, respectively. Conclusions: Our present data will be helpful for identifying n-butyl cyanide at millimeter or longer wavelengths with radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular, its detection in Sagittarius B2(N) with ALMA seems feasible. Full Table 3 and Tables 4-5 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/541/A121

  12. Data reduction of digitized images processed from calibrated photographic and spectroscopic films obtained from terrestial, rocket and space shuttle telescopic instruments

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.

    1990-01-01

    The Microvax 2 computer, the basic software in VMS, and the Mitsubishi High Speed Disk were received and installed. The digital scanning tunneling microscope is fully installed and operational. A new technique was developed for pseudocolor analysis of the line plot images of a scanning tunneling microscope. Computer studies and mathematical modeling of the empirical data associated with many of the film calibration studies were presented. A gas can follow-up experiment which will be launched in September, on the Space Shuttle STS-50, was prepared and loaded. Papers were presented on the structure of the human hair strand using scanning electron microscopy and x ray analysis and updated research on the annual rings produced by the surf clam of the ocean estuaries of Maryland. Scanning electron microscopic work was conducted by the research team for the study of the Mossbauer and Magnetic Susceptibility Studies on NmNi(4.25)Fe(.85) and its Hydride.

  13. A Prototype Search Toolkit

    NASA Astrophysics Data System (ADS)

    Knepper, Margaret M.; Fox, Kevin L.; Frieder, Ophir

    Information overload is now a reality. We no longer worry about obtaining a sufficient volume of data; we now are concerned with sifting and understanding the massive volumes of data available to us. To do so, we developed an integrated information processing toolkit that provides the user with a variety of ways to view their information. The views include keyword search results, a domain specific ranking system that allows for adaptively capturing topic vocabularies to customize and focus the search results, navigation pages for browsing, and a geospatial and temporal component to visualize results in time and space, and provide “what if” scenario playing. Integrating the information from different tools and sources gives the user additional information and another way to analyze the data. An example of the integration is illustrated on reports of the avian influenza (bird flu).

  14. Higgs Searches

    SciTech Connect

    Peters, Krisztian

    2009-11-01

    We present the status and prospects of Higgs searches at the Tevatron and the LHC. Results from the Tevatron are using up to 5 fb{sup -} of data collected with the CDF and D0 detectors. The major contributing processes include associated production (WH {yields} l{nu}bb, ZH {yields} {nu}{nu}bb, ZH {yields} llbb) and gluon fusion (gg {yields} H {yields} WW{sup (*)}). Improvements across the full mass range resulting from the larger data sets, improved analyses techniques and increased signal acceptance are discussed. Recent results exclude the SM Higgs boson in a mass range of 160 < m{sub H} < 170 GeV. Searches for the neutral MSSM Higgs boson in the region 90 < m{sub A} < 200 GeV exclude tan {beta} values down to 30 for several benchmark scenarios.

  15. AI in Space: The Era of Autonomous Space Systems

    NASA Technical Reports Server (NTRS)

    Doyle, Richard J.

    2000-01-01

    The development of autonomy capabilities is the key to three vastly important strategic technical challenges facing NASA: the reduction of mission costs, the continuing return of quality science products through limited communications bandwidth, and the launching of a new era of solar system exploration characterized by sustained presence and in-depth scientific studies, including the search for life. Autonomy will benefit future NASA missions by migrating routine, traditionally ground-based functions to the spacecraft, by directly supporting the decoupling of spacecraft from the ground through new operations concepts, by enabling direct links between scientists and the space platforms carrying their instruments of investigation, and by the closing, of planning and control loops onboard, enabling space platforms to directly address uncertainty in the real-time mission context. The talk will survey ongoing, autonomy technology development projects at NASA, many of which have been or will soon be the subject of flight technology experiments, or are already targeted for mission use. The talk will also survey the exciting suite of future NASA space exploration missions, and make the case for the central role of autonomy in achieving the goals of these bold, unprecedented missions: cooperating rovers on the surface of Mars, the search for Earth-like planets around nearby stars, asteroid and comet landers, aerobots in planetary atmospheres, and a series of missions to intriguing Europa, perhaps culminating in a submersible to investigate its putative ocean. Finally, the talk will conclude with some farther-reaching speculations on how to create properties such as long-term survivability and evolvability in future space systems, such that they will be well equipped to extend humanity exploratory presence into the interstellar realm.

  16. Study to evaluate the effect of EVA on payload systems. Volume 1: Executive summary. [project planning of space missions employing extravehicular activity as a means of cost reduction

    NASA Technical Reports Server (NTRS)

    Patrick, J. W.; Kraly, E. F.

    1975-01-01

    Programmatic benefits to payloads are examined which can result from the routine use of extravehicular activity (EVA) during space missions. Design and operations costs were compared for 13 representative baseline payloads to the costs of those payloads adapted for EVA operations. The EVA-oriented concepts developed in the study were derived from these baseline concepts and maintained mission and program objectives as well as basic configurations. This permitted isolation of cost saving factors associated specifically with incorporation of EVA in a variety of payload designs and operations. The study results were extrapolated to a total of 74 payload programs. Using appropriate complexity and learning factors, net EVA savings were extrapolated to over $551M for NASA and U.S. civil payloads for routine operations. Adding DOD and ESRO payloads increases the net estimated savings of $776M. Planned maintenance by EVA indicated an estimated $168M savings due to elimination of automated service equipment. Contingency problems of payloads were also analyzed to establish expected failure rates for shuttle payloads. The failure information resulted in an estimated potential for EVA savings of $1.9 B.

  17. Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 2: High pressure oxidizer turbo-pump turbine end bearing analysis

    NASA Technical Reports Server (NTRS)

    Sisk, Gregory A.

    1989-01-01

    The high-pressure oxidizer turbopump (HPOTP) consists of two centrifugal pumps, on a common shaft, that are directly driven by a hot-gas turbine. Pump shaft axial thrust is balanced in that the double-entry main inducer/impeller is inherently balanced and the thrusts of the preburner pump and turbine are nearly equal but opposite. Residual shaft thrust is controlled by a self-compensating, non-rubbing, balance piston. Shaft hang-up must be avoided if the balance piston is to perform properly. One potential cause of shaft hang-up is contact between the Phase 2 bearing support and axial spring cartridge of the HPOTP main pump housing. The status of the bearing support/axial spring cartridge interface is investigated under current loading conditions. An ANSYS version 4.3, three-dimensional, finite element model was generated on Lockheed's VAX 11/785 computer. A nonlinear thermal analysis was then executed on the Marshall Space Flight Center Engineering Analysis Data System (EADS). These thermal results were then applied along with the interference fit and bolt preloads to the model as load conditions for a static analysis to determine the gap status of the bearing support/axial spring cartridge interface. For possible further analysis of the local regions of HPOTP main pump housing assembly, detailed ANSYS submodels were generated using I-DEAS Geomod and Supertab (Appendix A).

  18. DOD Space Test Program (STP)

    NASA Technical Reports Server (NTRS)

    Smith, Llwyn

    1995-01-01

    This paper describes the Space Test Program (STP) which provides access to space for the DOD-wide space research and development (R&D) community. STP matches a ranked list of sanctioned experiments with available budgets and searches for the most cost effective mechanisms to get the experiments into space. The program has successfully flown over 350 experiments, using dedicated freeflyer spacecraft, secondary space on the Space Shuttle, and various host satellites.

  19. Preschoolers Search for Hidden Objects

    ERIC Educational Resources Information Center

    Haddad, Jeffrey M.; Chen, Yuping; Keen, Rachel

    2011-01-01

    The issue of whether young children use spatio-temporal information (e.g., movement of objects through time and space) and/or contact-mechanical information (e.g., interaction between objects) to search for a hidden object was investigated. To determine whether one cue can have priority over the other, a dynamic event that put these cues into…

  20. Four-Dimensional Golden Search

    SciTech Connect

    Fenimore, Edward E.

    2015-02-25

    The Golden search technique is a method to search a multiple-dimension space to find the minimum. It basically subdivides the possible ranges of parameters until it brackets, to within an arbitrarily small distance, the minimum. It has the advantages that (1) the function to be minimized can be non-linear, (2) it does not require derivatives of the function, (3) the convergence criterion does not depend on the magnitude of the function. Thus, if the function is a goodness of fit parameter such as chi-square, the convergence does not depend on the noise being correctly estimated or the function correctly following the chi-square statistic. And, (4) the convergence criterion does not depend on the shape of the function. Thus, long shallow surfaces can be searched without the problem of premature convergence. As with many methods, the Golden search technique can be confused by surfaces with multiple minima.

  1. Searches for supersymmetry at the Tevatron

    SciTech Connect

    Lytken, Else; /Purdue U.

    2006-05-01

    The results for searches for Supersymmetry at the Tevatron Collider are summarized in this paper. They focus here on searches for chargino/neutralino and the lightest stop, as well as scenarios with R-parity violation and split supersymmetry. No significant excesses with respect to the Standard Model were observed and constraints are set on the SUSY parameter space.

  2. Background reduction in cryogenic detectors

    SciTech Connect

    Bauer, Daniel A.; /Fermilab

    2005-04-01

    This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.

  3. Web Search Engines: Search Syntax and Features.

    ERIC Educational Resources Information Center

    Ojala, Marydee

    2002-01-01

    Presents a chart that explains the search syntax, features, and commands used by the 12 most widely used general Web search engines. Discusses Web standardization, expanded types of content searched, size of databases, and search engines that include both simple and advanced versions. (LRW)

  4. Space biology research development

    NASA Technical Reports Server (NTRS)

    Bonting, Sjoerd L.

    1993-01-01

    The purpose of the Search for Extraterrestrial Intelligence (SETI) Institute is to conduct and promote research related activities regarding the search for extraterrestrial life, particularly intelligent life. Such research encompasses the broad discipline of 'Life in the Universe', including all scientific and technological aspects of astronomy and the planetary sciences, chemical evolution, the origin of life, biological evolution, and cultural evolution. The primary purpose was to provide funding for the Principal Investigator to collaborate with the personnel of the SETI Institute and the NASA-Ames Research center in order to plan and develop space biology research on and in connection with Space Station Freedom; to promote cooperation with the international partners in the space station; to conduct a study on the use of biosensors in space biology research and life support system operation; and to promote space biology research through the initiation of an annual publication 'Advances in Space Biology and Medicine'.

  5. Generalized topological spaces in evolutionary theory and combinatorial chemistry.

    PubMed

    Stadler, Bärbel M R; Stadler, Peter F

    2002-01-01

    The search spaces in combinatorial chemistry as well as the sequence spaces underlying (molecular) evolution are conventionally thought of as graphs. Recombination, however, implies a nongraphical structure of the combinatorial search spaces. These structures, and their implications for search process itself, are heretofore not well understood in general. In this contribution we review a very general formalism from point set topology and discuss its application to combinatorial search spaces, fitness landscapes, evolutionary trajectories, and artificial chemistries.

  6. A drunken search in crystallization space.

    PubMed

    Fazio, Vincent J; Peat, Thomas S; Newman, Janet

    2014-10-01

    The REMARK280 field of the Protein Data Bank is the richest open source of successful crystallization information. The REMARK280 field is optional and currently uncurated, so significant effort needs to be applied to extract reliable data. There are well over 15 000 crystallization conditions available commercially from 12 different vendors. After putting the PDB crystallization information and the commercial cocktail data into a consistent format, these data are used to extract information about the overlap between the two sets of crystallization conditions. An estimation is made as to which commercially available conditions are most appropriate for producing well diffracting crystals by looking at which commercial conditions are found unchanged (or almost unchanged) in the PDB. Further analyses include which commercial kits are the most appropriate for shotgun or more traditional approaches to crystallization screening. This analysis suggests that almost 40% of the crystallization conditions found currently in the PDB are identical or very similar to a commercial condition.

  7. Dynamic Action Spaces for Autonomous Search Operations

    DTIC Science & Technology

    2005-06-01

    is equal to the conditional probability of detecting a clue given a clue had been deposited, )( αα kk CDp , multiplied by the probability that a...deposit frequencies. The conditional probability )( αα kk CDp is equivalent to the sensor detection rate introduced earlier, where the probability of...unitstime radiansarctan 22 Ki v xcyc yc xc t A s sxsy sy sx i ii i i ∈∀ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ −+− ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − − =⎥ ⎦ ⎤ ⎢ ⎣ ⎡ = θ

  8. Dual Space Search During Scientific Reasoning

    DTIC Science & Technology

    1987-09-29

    and in the criteria for revising hypotheses. (The "simulated universe" tasks used by Mynatt . Doherty & Tweney [1977. 19781 include similar extensions...studies Is that when subjects design experiments, they show a pervasive confirmation bias ( Mynatt , Doherty, and Tweney, 1977; 1978).. They propose a...research can also be interpreted in this manner; for example, Mynatt et al. (1977, 1978) used a task in which subjects had to discover the laws of repulsion

  9. Space Acquired Photography

    USGS Publications Warehouse

    ,

    2008-01-01

    Interested in a photograph of the first space walk by an American astronaut, or the first photograph from space of a solar eclipse? Or maybe your interest is in a specific geologic, oceanic, or meteorological phenomenon? The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center is making photographs of the Earth taken from space available for search, download, and ordering. These photographs were taken by Gemini mission astronauts with handheld cameras or by the Large Format Camera that flew on space shuttle Challenger in October 1984. Space photographs are distributed by EROS only as high-resolution scanned or medium-resolution digital products.

  10. Space acquired photography

    USGS Publications Warehouse

    ,

    2008-01-01

    Interested in a photograph of the first space walk by an American astronaut, or the first photograph from space of a solar eclipse? Or maybe your interest is in a specific geologic, oceanic, or meteorological phenomenon? The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center is making photographs of the Earth taken from space available for search, download, and ordering. These photographs were taken by Gemini mission astronauts with handheld cameras or by the Large Format Camera that flew on space shuttle Challenger in October 1984. Space photographs are distributed by EROS only as high-resolution scanned or medium-resolution digital products.

  11. Enhanced algorithms for enterprise expert search system

    NASA Astrophysics Data System (ADS)

    Molokanov, Valentin; Romanov, Dmitry; Tsibulsky, Valentin

    2013-03-01

    We present the results of our enterprise expert search system application to the task introduced at the Text Retrieval Conference (TREC) in 2007. The expert search system is based on analysis of content and communications topology in an enterprise information space. An optimal set of weighting coefficients for three query-candidate associating algorithms is selected for achieving the best search efficiency on the search collection. The obtained performance proved to be better than at most TREC participants. The hypothesis of additional efficiency improvement by means of query classification is proposed.

  12. Antenna concepts for interstellar search systems

    NASA Technical Reports Server (NTRS)

    Basler, R. P.; Johnson, G. L.; Vondrak, R. R.

    1977-01-01

    An evaluation is made of microwave receiving systems designed to search for signals from extraterrestrial intelligence. Specific design concepts are analyzed parametrically to determine whether the optimum antenna system location is on earth, in space, or on the moon. Parameters considered include the hypothesized number of transmitting civilizations, the number of stars that must be searched to give any desired probability of receiving a signal, the antenna collecting area, the search time, the search range, and the cost. This analysis suggests that (1) search systems based on the moon are not cost-competitive, (2) if the search is extended only a few hundred light years from the earth, a Cyclops-type array on earth may be the most cost-effective system, (3) for a search extending to 500 light years or more, a substantial cost and search-time advantage can be achieved with a large spherical reflector in space with multiple feeds, (4) radio frequency interference shields can be provided for space systems, and (5) cost can range from a few hundred million to tens of billions of dollars, depending on the parameter values assumed.

  13. Modelling and Simulation of Search Engine

    NASA Astrophysics Data System (ADS)

    Nasution, Mahyuddin K. M.

    2017-01-01

    The best tool currently used to access information is a search engine. Meanwhile, the information space has its own behaviour. Systematically, an information space needs to be familiarized with mathematics so easily we identify the characteristics associated with it. This paper reveal some characteristics of search engine based on a model of document collection, which are then estimated the impact on the feasibility of information. We reveal some of characteristics of search engine on the lemma and theorem about singleton and doubleton, then computes statistically characteristic as simulating the possibility of using search engine. In this case, Google and Yahoo. There are differences in the behaviour of both search engines, although in theory based on the concept of documents collection.

  14. Harm reduction

    PubMed Central

    Normand, Jacques; Li, Jih-Heng; Thomson, Nicholas; Jarlais, Don Des

    2014-01-01

    The “Harm Reduction” session was chaired by Dr. Jacques Normand, Director of the AIDS Research Program of the U.S. National Institute on Drug Abuse. The three presenters (and their presentation topics) were: Dr. Don Des Jarlais (High Coverage Needle/Syringe Programs for People Who Inject Drugs in Low and Middle Income Countries: A Systematic Review), Dr. Nicholas Thomson (Harm Reduction History, Response, and Current Trends in Asia), and Dr. Jih-Heng Li (Harm Reduction Strategies in Taiwan). PMID:25278732

  15. THE ROLE OF SEARCHING SERVICES IN AN ACQUISITIONS PROGRAM.

    ERIC Educational Resources Information Center

    LUECK, ANTOINETTE L.; AND OTHERS

    A USER PRESENTS HIS POINT OF VIEW ON LITERATURE SEARCHING THROUGH THE MAJOR SEARCHING SERVICES IN THE OVERALL PROGRAM OF ACQUISITIONS FOR THE ENGINEERING STAFF OF THE AIR FORCE AERO PROPULSION LABORATORY. THESE MAJOR SEARCHING SERVICES INCLUDE THE DEFENSE DOCUMENTATION CENTER (DDC), THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (NASA), THE…

  16. A search strategy for SETI - The search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Billingham, J.; Wolfe, J.; Edelson, R.; Gulkis, S.; Olsen, E.; Oliver, B.; Tarter, J.; Seeger, C.

    1980-01-01

    A search strategy is proposed for the detection of signals of extraterrestrial intelligent origin. It constitutes an exploration of a well defined volume of search space in the microwave region of the spectrum and envisages the use of a combination of sky survey and targeted star approaches. It is predicated on the use of existing antennas equipped with sophisticated multichannel spectrum analyzers and signal processing systems operating in the digital mode. The entire sky would be surveyed between 1 and 10 GHz with resolution bin widths down to 32 Hz. More than 700 nearby solar type stars and other selected interesting directions would be searched between 1 GHz and 3 GHz with bin widths down to 1 Hz. Particular emphasis would be placed on those solar type stars that are within 20 light years of earth.

  17. Waste Reduction.

    ERIC Educational Resources Information Center

    Bray, Marilyn; And Others

    1996-01-01

    Presents activities that focus on waste reduction in the school and community. The ideas are divided into grade level categories. Sample activities include Techno-Trash, where children use tools to take apart broken appliances or car parts, then reassemble them or build new creations. Activities are suggested for areas including language arts and…

  18. RADON REDUCTION IN A CRAWL SPACE HOUSE

    EPA Science Inventory

    Radon, a naturally occurring radioactive gas, is drawn from the soil into a house when low air pressure exists in the house. This is a commonplace environmental hazard in the United States, Canada, and northern Europe. The U.S. Environmental Protection Agency (EPA) is developing ...

  19. Optical interferometer in space

    NASA Technical Reports Server (NTRS)

    Bender, Peter L.; Faller, J. E.; Hall, J. L.; Hils, D.; Stebbins, R. T.; Vincent, Mark A.

    1989-01-01

    The present design concepts for a Laser Gravitational Wave Observatory in Space are described. Laser heterodyne distance measurements are made between test masses located in three spacecraft separated by roughly 10(exp 6) km. The major technology issues are: the reduction of spurious acceleration noise for the test masses to below 2 x 10(exp -15) cm/sq sec/Hz(0.5) from 10(exp -5) to 10(exp -3) Hz; and the measurement of changes in the difference of the antenna arm lengths to 5 x 10(exp -11) cm/Hz(0.5) from 10(exp -3) to 1 Hz with high reliability. The science objectives are: to measure discrete sinusoidal gravitational wave signals from individual sources with periods of 1 second to 1 day; to measure the stochastic background due to unresolved binaries; and to search for gravitational wave pulses with periods longer than 1 sec from possible exotic sources such as gravitational collapse of very massive objects.

  20. 'Net Search Strategies.

    ERIC Educational Resources Information Center

    Bell, Suzanne S.

    1997-01-01

    Provides strategies for effective Internet searches. Categorizes queries into four types and describes tools: subject lists; indexes/directories; keyword search engines; Usenet newsgroups; and special purpose search tools. Discusses the importance of deciphering information and adjusting to changes. (AEF)

  1. Mirador: A Simple, Fast Search Interface for Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Lynnes, Christopher; Strub, Richard; Seiler, Edward; Joshi, Talak; MacHarrie, Peter

    2008-01-01

    A major challenge for remote sensing science researchers is searching and acquiring relevant data files for their research projects based on content, space and time constraints. Several structured query (SQ) and hierarchical navigation (HN) search interfaces have been develop ed to satisfy this requirement, yet the dominant search engines in th e general domain are based on free-text search. The Goddard Earth Sci ences Data and Information Services Center has developed a free-text search interface named Mirador that supports space-time queries, inc luding a gazetteer and geophysical event gazetteer. In order to compe nsate for a slightly reduced search precision relative to SQ and HN t echniques, Mirador uses several search optimizations to return result s quickly. The quick response enables a more iterative search strateg y than is available with many SQ and HN techniques.

  2. Reduction Corporoplasty

    PubMed Central

    Hakky, Tariq S.; Martinez, Daniel; Yang, Christopher; Carrion, Rafael E.

    2015-01-01

    Objective Here we present the first video demonstration of reduction corporoplasty in the management of phallic disfigurement in a 17 year old man with a history sickle cell disease and priapism. Introduction Surgical management of aneurysmal dilation of the corpora has yet to be defined in the literature. Materials and Methods: We preformed bilateral elliptical incisions over the lateral corpora as management of aneurysmal dilation of the corpora to correct phallic disfigurement. Results The patient tolerated the procedure well and has resolution of his corporal disfigurement. Conclusions Reduction corporoplasty using bilateral lateral elliptical incisions in the management of aneurysmal dilation of the corpora is a safe an feasible operation in the management of phallic disfigurement. PMID:26005988

  3. Nitrate reduction

    DOEpatents

    Dziewinski, Jacek J.; Marczak, Stanislaw

    2000-01-01

    Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

  4. The Wisdom of Class-Size Reduction

    ERIC Educational Resources Information Center

    Graue, Elizabeth; Hatch, Kelly; Rao, Kalpana; Oen, Denise

    2007-01-01

    In this study, the authors explore the implementation of a statewide class-size reduction program in nine high-poverty schools. Through qualitative methods, they examined how schools used class-size reduction to change staffing patterns and instructional programs. Requiring changes in space allocation, class-size reduction was accomplished through…

  5. Combining Global Tabu Search with Local Search for Solving Systems of Equalities and Inequalities

    NASA Astrophysics Data System (ADS)

    Ramadas, Gisela C. V.; Fernandes, Edite M. G. P.

    2011-09-01

    This papers aims at providing a combined strategy for solving systems of equalities and inequalities. The combined strategy uses two types of steps: a global search step and a local search step. The global step relies on a tabu search heuristic and the local step uses a deterministic search known as Hooke and Jeeves. The choice of step, at each iteration, is based on the level of reduction of the l2-norm of the error function observed in the equivalent system of equations, compared with the previous iteration.

  6. Comparing NEO Search Telescopes

    NASA Astrophysics Data System (ADS)

    Myhrvold, Nathan

    2016-04-01

    Multiple terrestrial and space-based telescopes have been proposed for detecting and tracking near-Earth objects (NEOs). Detailed simulations of the search performance of these systems have used complex computer codes that are not widely available, which hinders accurate cross-comparison of the proposals and obscures whether they have consistent assumptions. Moreover, some proposed instruments would survey infrared (IR) bands, whereas others would operate in the visible band, and differences among asteroid thermal and visible-light models used in the simulations further complicate like-to-like comparisons. I use simple physical principles to estimate basic performance metrics for the ground-based Large Synoptic Survey Telescope and three space-based instruments—Sentinel, NEOCam, and a Cubesat constellation. The performance is measured against two different NEO distributions, the Bottke et al. distribution of general NEOs, and the Veres et al. distribution of Earth-impacting NEO. The results of the comparison show simplified relative performance metrics, including the expected number of NEOs visible in the search volumes and the initial detection rates expected for each system. Although these simplified comparisons do not capture all of the details, they give considerable insight into the physical factors limiting performance. Multiple asteroid thermal models are considered, including FRM, NEATM, and a new generalized form of FRM. I describe issues with how IR albedo and emissivity have been estimated in previous studies, which may render them inaccurate. A thermal model for tumbling asteroids is also developed and suggests that tumbling asteroids may be surprisingly difficult for IR telescopes to observe.

  7. Stacked Learning to Search for Scene Labeling.

    PubMed

    Cheng, Feiyang; He, Xuming; Zhang, Hong

    2017-02-13

    Search-based structured prediction methods have shown promising successes in both computer vision and natural language processing recently. However, most existing search-based approaches lead to a complex multi-stage learning process, which is ill-suited for scene labeling problems with a high-dimensional output space. In this paper, a stacked learning to search method is proposed to address scene labeling tasks. We design a simplified search process consisting of a sequence of ranking functions, which are learned based on a stacked learning strategy to prevent over-fitting. Our method is able to encode rich prior knowledge by incorporating a variety of local and global scene features. In addition, we estimate a labeling confidence map to further improve the search efficiency from two aspects: first, it constrains the search space more effectively by pruning out low-quality solutions based on confidence scores; second, we employ the confidence map as an additional ranking feature to improve its prediction performance and thus reduce the search steps. Our approach is evaluated on both semantic segmentation and geometric labeling tasks, including the Stanford Background, Sift Flow, Geometric Context and NYUv2 RGB-D dataset. The competitive results demonstrate that our stacked learning to search method provides an effective alternative paradigm for scene labeling.

  8. Life in space

    NASA Technical Reports Server (NTRS)

    West, John B.

    1992-01-01

    The scope of space life sciences and current research on the physiology of man in space are reviewed by examining Spacelab SLS-1. Milestones of space life sciences are discussed, with emphasis on the Skylab facility, the Space Shuttle program, and the Soviet Mir space station. Attention is given to the topic of the origins of life as it relates to space life sciences. The discovery of amino acids in meteorites and the question of whether the earth was seeded with life from space are discussed. A brief overview of efforts in the search for extraterrestrial intelligence is presented. Consideration is also given to the effects of gravity on cells, the effects of radiation, plant biology, CELSS, and the effects of gravity on humans.

  9. Performance comparison of the automatic data reduction system (ADRS)

    NASA Astrophysics Data System (ADS)

    Patterson, Dan; Turner, David; Concepcion, Arturo; Lynch, Robert

    2008-03-01

    In this paper, real data sets from the UCI Repository are mined and quantized to reduce the dimensionality of the feature space for best classification performance. The approach utilized to mine the data is based on the Bayesian Data Reduction Algorithm (BDRA), which has been recently developed into a windows based system by California State University (see http://wiki.csci.csusb.edu/bdra/Main_Page) called the Automatic Data Reduction System (ADRS). The primary contribution of this work will be to demonstrate and compare different approaches to the feature search (e.g., forward versus backward searching), and show how performance is impacted for each data set. Additionally, the performance of the ADRS with the UCI data will be compared to an Artificial Neural Network (ANN). In this case, results are shown for the ANN both with and without the utilization of Principal Components Analysis (PCA) to reduce the dimension of the feature data. Overall, it is shown that the BDRA's performance with the UCI data is superior to that of the ANN.

  10. Dimension Reduction for Object Ranking

    NASA Astrophysics Data System (ADS)

    Kamishima, Toshihiro; Akaho, Shotaro

    Ordered lists of objects are widely used as representational forms. Such ordered objects include Web search results and bestseller lists. Techniques for processing such ordinal data are being developed, particularly methods for an object ranking task: i.e., learning functions used to sort objects from sample orders. In this article, we propose two dimension reduction methods specifically designed to improve prediction performance in an object ranking task.

  11. Online Database Searching Workbook.

    ERIC Educational Resources Information Center

    Littlejohn, Alice C.; Parker, Joan M.

    Designed primarily for use by first-time searchers, this workbook provides an overview of online searching. Following a brief introduction which defines online searching, databases, and database producers, five steps in carrying out a successful search are described: (1) identifying the main concepts of the search statement; (2) selecting a…

  12. Search Alternatives and Beyond

    ERIC Educational Resources Information Center

    Bell, Steven J.

    2006-01-01

    Internet search has become a routine computing activity, with regular visits to a search engine--usually Google--the norm for most people. The vast majority of searchers, as recent studies of Internet search behavior reveal, search only in the most basic of ways and fail to avail themselves of options that could easily and effortlessly improve…

  13. Multimedia Web Searching Trends.

    ERIC Educational Resources Information Center

    Ozmutlu, Seda; Spink, Amanda; Ozmutlu, H. Cenk

    2002-01-01

    Examines and compares multimedia Web searching by Excite and FAST search engine users in 2001. Highlights include audio and video queries; time spent on searches; terms per query; ranking of the most frequently used terms; and differences in Web search behaviors of U.S. and European Web users. (Author/LRW)

  14. Virasoro model space

    NASA Astrophysics Data System (ADS)

    La, Hoseong; Nelson, Philip; Schwarz, A. S.

    1990-12-01

    The representations of a compact Lie group G can be studied via the construction of an associated “model space.” This space has the property that when geometrically quantized its Hilbert space contains every irreducible representation of G just once. We construct an analogous space for the group Diff S 1. It is naturally a complex manifold with a holomorphic, free action of Diff S 1 preserving a family of pseudo-Kahler structures. All of the “good” coadjoint orbits are obtained from our space by Hamiltonian constraint reduction. We briefly discuss the connection to the work of Alekseev and Shatashvili.

  15. Geometric Quantization and Foliation Reduction

    NASA Astrophysics Data System (ADS)

    Skerritt, Paul

    A standard question in the study of geometric quantization is whether symplectic reduction interacts nicely with the quantized theory, and in particular whether "quantization commutes with reduction." Guillemin and Sternberg first proposed this question, and answered it in the affirmative for the case of a free action of a compact Lie group on a compact Kahler manifold. Subsequent work has focused mainly on extending their proof to non-free actions and non-Kahler manifolds. For realistic physical examples, however, it is desirable to have a proof which also applies to non-compact symplectic manifolds. In this thesis we give a proof of the quantization-reduction problem for general symplectic manifolds. This is accomplished by working in a particular wavefunction representation, associated with a polarization that is in some sense compatible with reduction. While the polarized sections described by Guillemin and Sternberg are nonzero on a dense subset of the Kahler manifold, the ones considered here are distributional, having support only on regions of the phase space associated with certain quantized, or "admissible", values of momentum. We first propose a reduction procedure for the prequantum geometric structures that "covers" symplectic reduction, and demonstrate how both symplectic and prequantum reduction can be viewed as examples of foliation reduction. Consistency of prequantum reduction imposes the above-mentioned admissibility conditions on the quantized momenta, which can be seen as analogues of the Bohr-Wilson-Sommerfeld conditions for completely integrable systems. We then describe our reduction-compatible polarization, and demonstrate a one-to-one correspondence between polarized sections on the unreduced and reduced spaces. Finally, we describe a factorization of the reduced prequantum bundle, suggested by the structure of the underlying reduced symplectic manifold. This in turn induces a factorization of the space of polarized sections that agrees

  16. Equivalent beam modeling using numerical reduction techniques

    NASA Technical Reports Server (NTRS)

    Chapman, J. M.; Shaw, F. H.

    1987-01-01

    Numerical procedures that can accomplish model reductions for space trusses were developed. Three techniques are presented that can be implemented using current capabilities within NASTRAN. The proposed techniques accomplish their model reductions numerically through use of NASTRAN structural analyses and as such are termed numerical in contrast to the previously developed analytical techniques. Numerical procedures are developed that permit reductions of large truss models containing full modeling detail of the truss and its joints. Three techniques are presented that accomplish these model reductions with various levels of structural accuracy. These numerical techniques are designated as equivalent beam, truss element reduction, and post-assembly reduction methods. These techniques are discussed in detail.

  17. A High-Altitude Search for Vulcanoids: Progress Report

    NASA Astrophysics Data System (ADS)

    Durda, D. D.; Stern, S. A.; Terrell, D. C.; Weidenschilling, S. J.

    2002-09-01

    We are conducting a unique, high-altitude observing campaign to search for vulcanoids, a population of small, asteroid-like bodies hypothesized to reside in the dynamically stable region interior to Mercury's orbit (i.e., orbits with aphelia <0.21 AU). This airborne search campaign utilizes our versatile and highly capable SWUIS-A (Southwest Universal Imaging System - Airborne) instrument flown with the flight astronomer (SAS and DDD) to an altitude of 49,000 MSL aboard NASA F/A-18B aircraft in order to obtain darker twilight conditions for near-Sun observing than are possible from the ground. The first observing run was successfully completed at NASA's Dryden Flight Research Center during the March/April 2002 vernal equinox observing opportunity. On each of the three evening flights we recorded image data covering 250 square degrees of sky centered on the ecliptic from solar elongations of 6-18 deg. Initial reduction of portions of the Mar/Apr 2002 data set demonstrates that we are reliably detecting objects to magnitude V = 9.5 at 15 degrees solar elongation. This is at least a magnitude fainter than the best previous ground-based searches and comparable to the faintest stars visible in our space-based SOHO LASCO C3 coronagraph vulcanoids search. The SWUIS-A instrument itself is capable of imaging objects as faint as magnitude V = 13, corresponding to vulcanoids less than 10 km across, with a sufficiently dark sky background; we are working to mitigate sky background brightness to reach these deeper magnitude limits for a second F/A-18B observing run during the September 2002 autumnal equinox observing opportunity. We thank NASA research pilots Rick Searfoss, Dana Purifoy, and Craig Bomben. This research is supported by the NASA Planetary Astronomy program, NASA's Dryden Flight Research Center, and the National Geographic Society.

  18. A flexible search strategy for production systems

    NASA Technical Reports Server (NTRS)

    Dey, Pradip; Srinivasan, S.; Sundararaghavan, K. R.

    1988-01-01

    Most problems considered to be solvable by expert systems have very large search space. It is imperative to use efficient search strategy in expert system tools. Thus, OPS5 uses a kind of hill climbing which is very efficient. However, hill climbing is inadequate for many problems because it is one of the least dependable search strategies. In order to make the search efficient and adequate one can: (1) adopt best-first search instead of hill climbing, or (2) modify hill climbing with intelligent backtracking. The second alternative is adopted. It is implemented in a production system called PRO2 embedded in C running on UNIX. It is called hill tracking. It is a general purpose tool for developing expert systems. This is a rule based production system with an effective, intelligent and flexible backtracking control mechanism, which makes the system more dependable. The advantages and disadvantages of PRO2 are discussed.

  19. AU-18 Space Primer

    DTIC Science & Technology

    2009-09-01

    average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed...MISSIONS . . . . 143 National Reconnaissance Office . . . . . . . . . . . . . . . . . . 143 National Geospatial- Intelligence Agency...165 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 13 US SPACE-BASED INTELLIGENCE

  20. The TSTS Method in Cultural Heritage Search

    NASA Astrophysics Data System (ADS)

    Stawniak, Mirosław; Cellary, Wojciech

    In cultural heritage content management systems in which cultural objects are described with the use of their semantic, temporal and spatial properties, the search capabilities taking all those properties into consideration are very limited. The difficulty comes from the fact that concepts evolve over time and depend on location. In this paper the TSTS search method is presented based on the TST similarity measure that allows assessing the similarity factor between different resources in a knowledgebase. A ranked search result is generated basing on the semantic distance between the fuzzy set created for the user query and fuzzy sets describing potential results in the time-space continuum.

  1. Remarks on global optimization using space-filling curves

    NASA Astrophysics Data System (ADS)

    Lera, Daniela; Sergeyev, Yaroslav

    2016-10-01

    The problem of finding the global minimum of a real function on a set S ⊆ RN occurs in many real world problems. In this paper, the global optimization problem with a multiextremal objective function satisfying the Lipschitz condition over a hypercube is considered. We propose a local tuning technique that adaptively estimates the local Lipschitz constants over different zones of the search region and a technique, called the local improvement, in order to accelerate the search. Peano-type space-filling curves for reduction of the dimension of the problem are used. Convergence condition are given. Numerical experiments executed on several hundreds of test functions show quite a promising performance of the introduced acceleration techniques.

  2. Progress in space biology.

    PubMed

    Imshenetskii, A A

    1979-01-01

    Over the past two decades there has arisen a new branch of biology--space biology. This short review is devoted to a discussion of its achievements. It considers the results of research in the area of gravitation biology, and an account is made of studies in those areas of radiobiology which have relevance to the study of the cosmos. There is a brief summary of the results of the search for the upper and lower limits of the biosphere, and information is presented regarding the measures employed to maintain planetary quarantine. A great deal of attention has been given to the search for extraterrestrial life, one of the most important of problems. The results obtained with the aid of the American Viking probes on Mars are given special attention. The review presents experimental data based both upon data obtained in experiments on biological specimens during space flights of satellites and space vehicles, and also upon the results of laboratory research.

  3. A Semi-Automatic Variability Search

    NASA Astrophysics Data System (ADS)

    Maciejewski, G.; Niedzielski, A.

    Technical features of the Semi-Automatic Variability Search (SAVS) operating at the Astronomical Observatory of the Nicolaus Copernicus University and the results of the first year of observations are presented. The user-friendly software developed for reduction of acquired CCD images and detection of new variable stars is also described.

  4. Mathematical physics: Search research

    NASA Astrophysics Data System (ADS)

    Shlesinger, Michael F.

    2006-09-01

    How does one best search for non-replenishable targets at unknown positions? An optimized search strategy could be applied to situations as diverse as animal foraging and time-sensitive rescue missions.

  5. Collider searches for extra dimensions

    SciTech Connect

    Landsberg, Greg; /Brown U.

    2004-12-01

    Searches for extra spatial dimensions remain among the most popular new directions in our quest for physics beyond the Standard Model. High-energy collider experiments of the current decade should be able to find an ultimate answer to the question of their existence in a variety of models. Until the start of the LHC in a few years, the Tevatron will remain the key player in this quest. In this paper, we review the most recent results from the Tevatron on searches for large, TeV{sup -1}-size, and Randall-Sundrum extra spatial dimensions, which have reached a new level of sensitivity and currently probe the parameter space beyond the existing constraints. While no evidence for the existence of extra dimensions has been found so far, an exciting discovery might be just steps away.

  6. Fixed-point quantum search.

    PubMed

    Grover, Lov K

    2005-10-07

    The quantum search algorithm consists of an iterative sequence of selective inversions and diffusion type operations, as a result of which it is able to find a state with desired properties (target state) in an unsorted database of size N in only sqrt[N] queries. This is achieved by designing the iterative transformations in a way that each iteration results in a small rotation of the state vector in a two-dimensional Hilbert space that includes the target state; if we choose the right number of iterative steps, we will stop just at the target state. This Letter shows that by replacing the selective inversions by selective phase shifts of pi/3, the algorithm preferentially converges to the target state irrespective of the step size or number of iterations. This feature leads to robust search algorithms and also to new schemes for quantum control and error correction.

  7. Quantum Search and Beyond

    DTIC Science & Technology

    2008-07-02

    solution of certain problems for which the communication needs do not dominate. A similar situation prevails in the quantum world. Quantum teleportation and...REPORT Quantum Search and Beyond 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Ten years ago, the quantum search algorithm was designed to provide a way...P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS quantum searching - partial quantum searching, fixed-point quantum

  8. Inside a Search. Commentary

    ERIC Educational Resources Information Center

    Cooper, Rosie

    2011-01-01

    Lou Marinoff's article, "Inside a Search," discusses the issues college search committees face in the pursuit of qualified faculty members that will be a good fit for their institutions. More often than not, faculty searches are more complex and challenging than the featured article suggests. The economic downturn facing the nation has resulted in…

  9. Basics of Online Searching.

    ERIC Educational Resources Information Center

    Meadow, Charles T.; Cochrane, Pauline (Atherton)

    Intended to teach the principles of interactive bibliographic searching to those with little or no prior experience, this textbook explains the basic elements of online information retrieval and compares the major database search systems. Its chapters address (1) relevant definitions and vocabulary; (2) the conceptual facets of database searching,…

  10. The modern trends in space electromagnetic instrumentation

    NASA Astrophysics Data System (ADS)

    Korepanov, V. E.

    The future trends of the experimental plasma physics development in outer space demand more and more exact and sophisticated scientific instrumentation. Moreover, the situation is complicated by constant reduction of financial support of scientific research, even in leading countries. This resulted in the development of mini; micro and nanosatellites with low price and short preparation time. Consequently, it provoked the creation of new generation of scientific instruments with reduced weight and power consumption but increased level of metrological parameters. The recent state of the development of electromagnetic (EM) sensors for microsatellites is reported. For flux-gate magnetometers (FGM) the reduction of weight as well as power consumption was achieved not only due to the use of new electronic components but also because of the new operation mode development. The scientific and technological study allowed to decrease FGM noise and now the typical noise figure is about 10 picotesla rms at 1 Hz and the record one is below 1 picotesla. The super-light version of search-coil magnetometers (SCM) was created as the result of intensive research. These new SCMs can have about six decades of operational frequency band with upper limit ˜ 1 MHz and noise level of few femtotesla with total weight about 75 grams, including electronics. A new instrument.- wave probe (WP) - which combines three independent sensors in one body - SCM, split Langmuir probe and electric potential sensor - was created. The developed theory confirms that WP can directly measure the wave vector components in space plasmas.

  11. Ringed Seal Search for Global Optimization via a Sensitive Search Model.

    PubMed

    Saadi, Younes; Yanto, Iwan Tri Riyadi; Herawan, Tutut; Balakrishnan, Vimala; Chiroma, Haruna; Risnumawan, Anhar

    2016-01-01

    The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS) is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive) and exploitation (intensive) of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be used in global

  12. Ringed Seal Search for Global Optimization via a Sensitive Search Model

    PubMed Central

    Saadi, Younes; Yanto, Iwan Tri Riyadi; Herawan, Tutut; Balakrishnan, Vimala; Chiroma, Haruna; Risnumawan, Anhar

    2016-01-01

    The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS) is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive) and exploitation (intensive) of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be used in global

  13. Interhemispheric integration in visual search

    PubMed Central

    Shipp, Stewart

    2011-01-01

    component of response time, with individual subjects capable of opposite hemifield biases. The results are interpretable by a guided search model of spatial attention – a first, parallel stage guiding selection by a second, serial stage – with the proviso that the first stage is relatively insular within each hemisphere. The bilateral advantage in search efficiency can then be attributed to a relative gain in target weight within the initial parallel stage, owing to a reduction in distractor competition mediated specifically by intrahemispheric circuitry. In the absence of a target there is no effective guidance, and hence no basis for a bilateral advantage to enhance search efficiency; the equivalence of scanning speed for the two display modes (bilateral and unilateral) implies a unitary second-stage process mediated via efficient interhemispheric integration. PMID:21640738

  14. Bidirectional Search in a String with Wavelet Trees

    NASA Astrophysics Data System (ADS)

    Schnattinger, Thomas; Ohlebusch, Enno; Gog, Simon

    Searching for genes encoding microRNAs (miRNAs) is an important task in genome analysis. Because the secondary structure of miRNA (but not the sequence) is highly conserved, the genes encoding it can be determined by finding regions in a genomic DNA sequence that match the structure. It is known that algorithms using a bidirectional search on the DNA sequence for this task outperform algorithms based on unidirectional search. The data structures supporting a bidirectional search (affix trees and affix arrays), however, are rather complex and suffer from their large space consumption. Here, we present a new data structure called bidirectional wavelet index that supports bidirectional search with much less space. With this data structure, it is possible to search for RNA secondary structural patterns in large genomes, for example the human genome.

  15. Shuttle Shortfalls and Lessons Learned for the Sustainment of Human Space Exploration

    NASA Technical Reports Server (NTRS)

    Zapata, Edgar; Levack, Daniel J. H.; Rhodes, Russell E.; Robinson, John W.

    2009-01-01

    Much debate and national soul searching has taken place over the value of the Space Shuttle which first flew in 1981 and which is currently scheduled to be retired in 2010. Originally developed post-Saturn Apollo to emphasize affordability and safety, the reusable Space Shuttle instead came to be perceived as economically unsustainable and lacking the technology maturity to assure safe, routine access to low earth orbit (LEO). After the loss of two crews, aboard Challenger and Columbia, followed by the decision to retire the system in 2010, it is critical that this three decades worth of human space flight experience be well understood. Understanding of the past is imperative to further those goals for which the Space Shuttle was a stepping-stone in the advancement of knowledge. There was significant reduction in life cycle costs between the Saturn Apollo and the Space Shuttle. However, the advancement in life cycle cost reduction from Saturn Apollo to the Space Shuttle fell far short of its goal. This paper will explore the reasons for this shortfall. Shortfalls and lessons learned can be categorized as related to design factors, at the architecture, element and sub-system levels, as well as to programmatic factors, in terms of goals, requirements, management and organization. Additionally, no review of the Space Shuttle program and attempt to take away key lessons would be complete without a strategic review. That is, how do national space goals drive future space transportation development strategies? The lessons of the Space Shuttle are invaluable in all respects - technical, as in design, program-wise, as in organizational approach and goal setting, and strategically, within the context of the generational march toward an expanded human presence in space. Beyond lessons though (and the innumerable papers, anecdotes and opinions published on this topic) this paper traces tangible, achievable steps, derived from the Space Shuttle program experience, that must be

  16. [Advanced online search techniques and dedicated search engines for physicians].

    PubMed

    Nahum, Yoav

    2008-02-01

    In recent years search engines have become an essential tool in the work of physicians. This article will review advanced search techniques from the world of information specialists, as well as some advanced search engine operators that may help physicians improve their online search capabilities, and maximize the yield of their searches. This article also reviews popular dedicated scientific and biomedical literature search engines.

  17. University Students' Online Information Searching Strategies in Different Search Contexts

    ERIC Educational Resources Information Center

    Tsai, Meng-Jung; Liang, Jyh-Chong; Hou, Huei-Tse; Tsai, Chin-Chung

    2012-01-01

    This study investigates the role of search context played in university students' online information searching strategies. A total of 304 university students in Taiwan were surveyed with questionnaires in which two search contexts were defined as searching for learning, and searching for daily life information. Students' online search strategies…

  18. Integration of Metaheuristics: A Way to Improve Search Performance

    NASA Astrophysics Data System (ADS)

    See, Phen Chiak; Yew Wong, Kuan; Komarudin, Komarudin

    2009-08-01

    It is generally stated that hybridizing metaheuristics helps to achieve a better search performance when solving combinatorial optimization problems such as Quadratic Assignment Problems (QAPs). In this paper, the integration of two metaheuristics (Max-Min Ant System and Genetic Algorithm) is used to solve a QAP sample, and the search performance obtained is discussed. It is shown that the collaborative effect between these two algorithms helps to search the solution space more effectively, thus achieving a better quality solution.

  19. Quantum search algorithms on a regular lattice

    SciTech Connect

    Hein, Birgit; Tanner, Gregor

    2010-07-15

    Quantum algorithms for searching for one or more marked items on a d-dimensional lattice provide an extension of Grover's search algorithm including a spatial component. We demonstrate that these lattice search algorithms can be viewed in terms of the level dynamics near an avoided crossing of a one-parameter family of quantum random walks. We give approximations for both the level splitting at the avoided crossing and the effectively two-dimensional subspace of the full Hilbert space spanning the level crossing. This makes it possible to give the leading order behavior for the search time and the localization probability in the limit of large lattice size including the leading order coefficients. For d=2 and d=3, these coefficients are calculated explicitly. Closed form expressions are given for higher dimensions.

  20. Semantic search via concept annealing

    NASA Astrophysics Data System (ADS)

    Dunkelberger, Kirk A.

    2007-04-01

    Annealing, in metallurgy and materials science, is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. We define concept annealing as a lexical, syntactic, and semantic expansion capability (the removal of defects and the internal stresses that cause term- and phrase-based search failure) coupled with a directed contraction capability (semantically-related terms, queries, and concepts nucleate and grow to replace those originally deformed by internal stresses). These two capabilities are tied together in a control loop mediated by the information retrieval precision and recall metrics coupled with intuition provided by the operator. The specific representations developed have been targeted at facilitating highly efficient and effective semantic indexing and searching. This new generation of Find capability enables additional processing (i.e. all-source tracking, relationship extraction, and total system resource management) at rates, precisions, and accuracies previously considered infeasible. In a recent experiment, an order magnitude reduction in time to actionable intelligence and nearly three orderss magnitude reduction in false alarm rate was achieved.

  1. Nested Quantum Search and NP-Complete Problem

    NASA Technical Reports Server (NTRS)

    Williams, C.; Cerf, N. J.; Grover, L. K.

    1998-01-01

    A quantum algorithm is known that solves an unstructured search problem in a number of iterations of order square-root of d, where d is the dimension of the search space, whereas any classical algorithm scales as O(d).

  2. Changing Perspective: Zooming in and out during Visual Search

    ERIC Educational Resources Information Center

    Solman, Grayden J. F.; Cheyne, J. Allan; Smilek, Daniel

    2013-01-01

    Laboratory studies of visual search are generally conducted in contexts with a static observer vantage point, constrained by a fixation cross or a headrest. In contrast, in many naturalistic search settings, observers freely adjust their vantage point by physically moving through space. In two experiments, we evaluate behavior during free vantage…

  3. JSC Search System Usability Case Study

    NASA Technical Reports Server (NTRS)

    Meza, David; Berndt, Sarah

    2014-01-01

    The advanced nature of "search" has facilitated the movement from keyword match to the delivery of every conceivable information topic from career, commerce, entertainment, learning... the list is infinite. At NASA Johnson Space Center (JSC ) the Search interface is an important means of knowledge transfer. By indexing multiple sources between directorates and organizations, the system's potential is culture changing in that through search, knowledge of the unique accomplishments in engineering and science can be seamlessly passed between generations. This paper reports the findings of an initial survey, the first of a four part study to help determine user sentiment on the intranet, or local (JSC) enterprise search environment as well as the larger NASA enterprise. The survey is a means through which end users provide direction on the development and transfer of knowledge by way of the search experience. The ideal is to identify what is working and what needs to be improved from the users' vantage point by documenting: (1) Where users are satisfied/dissatisfied (2) Perceived value of interface components (3) Gaps which cause any disappointment in search experience. The near term goal is it to inform JSC search in order to improve users' ability to utilize existing services and infrastructure to perform tasks with a shortened life cycle. Continuing steps include an agency based focus with modified questions to accomplish a similar purpose

  4. 14 CFR 398.11 - Funding reductions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Funding reductions. 398.11 Section 398.11 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS GUIDELINES FOR INDIVIDUAL DETERMINATIONS OF BASIC ESSENTIAL AIR SERVICE § 398.11...

  5. 14 CFR 398.11 - Funding reductions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Funding reductions. 398.11 Section 398.11 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS GUIDELINES FOR INDIVIDUAL DETERMINATIONS OF BASIC ESSENTIAL AIR SERVICE § 398.11...

  6. 14 CFR 398.11 - Funding reductions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Funding reductions. 398.11 Section 398.11 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS GUIDELINES FOR INDIVIDUAL DETERMINATIONS OF BASIC ESSENTIAL AIR SERVICE § 398.11...

  7. 14 CFR 398.11 - Funding reductions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Funding reductions. 398.11 Section 398.11 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS GUIDELINES FOR INDIVIDUAL DETERMINATIONS OF BASIC ESSENTIAL AIR SERVICE § 398.11...

  8. 14 CFR 398.11 - Funding reductions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Funding reductions. 398.11 Section 398.11 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS GUIDELINES FOR INDIVIDUAL DETERMINATIONS OF BASIC ESSENTIAL AIR SERVICE § 398.11...

  9. Unitary Operators on the Document Space.

    ERIC Educational Resources Information Center

    Hoenkamp, Eduard

    2003-01-01

    Discusses latent semantic indexing (LSI) that would allow search engines to reduce the dimension of the document space by mapping it into a space spanned by conceptual indices. Topics include vector space models; singular value decomposition (SVD); unitary operators; the Haar transform; and new algorithms. (Author/LRW)

  10. Harm Reduction From Below

    PubMed Central

    Van Schipstal, Inge; Berning, Moritz; Murray, Hayley

    2016-01-01

    This article focuses on how recreational drug users in the Netherlands and in online communities navigate the risks and reduce the harms they associate with psychoactive drug use. To do so, we examined the protective practices they invent, use, and share with their immediate peers and with larger drug experimenting communities online. The labor involved in protective practices and that which ultimately informs harm reduction from below follows three interrelated trajectories: (1) the handling and sharing of drugs to facilitate hassle-free drug use, (2) creating pleasant and friendly spaces that we highlight under the practices of drug use attunements, and (3) the seeking and sharing of information in practices to spread the good high. We focus not only on users’ concerns but also on how these concerns shape their approach to drugs, what young people do to navigate uncertainties, and how they reach out to and create different sources of knowledge to minimize adversities and to improve highs. Harm reduction from below, we argue, can best be seen in the practices of sharing around drug use and in the caring for the larger community of drug-using peers. PMID:27721525

  11. Effective dimension reduction for sparse functional data.

    PubMed

    Yao, F; Lei, E; Wu, Y

    2015-06-01

    We propose a method of effective dimension reduction for functional data, emphasizing the sparse design where one observes only a few noisy and irregular measurements for some or all of the subjects. The proposed method borrows strength across the entire sample and provides a way to characterize the effective dimension reduction space, via functional cumulative slicing. Our theoretical study reveals a bias-variance trade-off associated with the regularizing truncation and decaying structures of the predictor process and the effective dimension reduction space. A simulation study and an application illustrate the superior finite-sample performance of the method.

  12. Effective dimension reduction for sparse functional data

    PubMed Central

    YAO, F.; LEI, E.; WU, Y.

    2015-01-01

    Summary We propose a method of effective dimension reduction for functional data, emphasizing the sparse design where one observes only a few noisy and irregular measurements for some or all of the subjects. The proposed method borrows strength across the entire sample and provides a way to characterize the effective dimension reduction space, via functional cumulative slicing. Our theoretical study reveals a bias-variance trade-off associated with the regularizing truncation and decaying structures of the predictor process and the effective dimension reduction space. A simulation study and an application illustrate the superior finite-sample performance of the method. PMID:26566293

  13. Demystifying the Search Button

    PubMed Central

    McKeever, Liam; Nguyen, Van; Peterson, Sarah J.; Gomez-Perez, Sandra

    2015-01-01

    A thorough review of the literature is the basis of all research and evidence-based practice. A gold-standard efficient and exhaustive search strategy is needed to ensure all relevant citations have been captured and that the search performed is reproducible. The PubMed database comprises both the MEDLINE and non-MEDLINE databases. MEDLINE-based search strategies are robust but capture only 89% of the total available citations in PubMed. The remaining 11% include the most recent and possibly relevant citations but are only searchable through less efficient techniques. An effective search strategy must employ both the MEDLINE and the non-MEDLINE portion of PubMed to ensure all studies have been identified. The robust MEDLINE search strategies are used for the MEDLINE portion of the search. Usage of the less robust strategies is then efficiently confined to search only the remaining 11% of PubMed citations that have not been indexed for MEDLINE. The current article offers step-by-step instructions for building such a search exploring methods for the discovery of medical subject heading (MeSH) terms to search MEDLINE, text-based methods for exploring the non-MEDLINE database, information on the limitations of convenience algorithms such as the “related citations feature,” the strengths and pitfalls associated with commonly used filters, the proper usage of Boolean operators to organize a master search strategy, and instructions for automating that search through “MyNCBI” to receive search query updates by email as new citations become available. PMID:26129895

  14. Low-Cost Radon Reduction Pilot Study

    SciTech Connect

    Rose, William B.; Francisco, Paul W.; Merrin, Zachary

    2015-09-01

    The aim of the research was to conduct a primary scoping study on the impact of air sealing between the foundation and the living space on radon transport reduction across the foundation-living space floor assembly. Fifteen homes in the Champaign, Illinois area participated in the study. These homes were instrumented for hourly continuous radon measurements and simultaneous temperature and humidity the foundation was improved. However, this improved isolation did not lead to significant reductions in radon concentration in the living space. Other factors such as outdoor temperature were shown to have an impact on radon concentration.

  15. SWT voting-based color reduction for text detection in natural scene images

    NASA Astrophysics Data System (ADS)

    Ikica, Andrej; Peer, Peter

    2013-12-01

    In this article, we propose a novel stroke width transform (SWT) voting-based color reduction method for detecting text in natural scene images. Unlike other text detection approaches that mostly rely on either text structure or color, the proposed method combines both by supervising text-oriented color reduction process with additional SWT information. SWT pixels mapped to color space vote in favor of the color they correspond to. Colors receiving high SWT vote most likely belong to text areas and are blocked from being mean-shifted away. Literature does not explicitly address SWT search direction issue; thus, we propose an adaptive sub-block method for determining correct SWT direction. Both SWT voting-based color reduction and SWT direction determination methods are evaluated on binary (text/non-text) images obtained from a challenging Computer Vision Lab optical character recognition database. SWT voting-based color reduction method outperforms the state-of-the-art text-oriented color reduction approach.

  16. Noise reduction for vocal pathologies.

    PubMed

    Matassini, L; Manfredi, C

    2002-01-01

    A noise reduction scheme, particularly suited for the correction of vocal pathologies, is proposed. The filter makes use of concepts originated within the theory of dynamical systems and deterministic chaos. In particular, the idea of embedding scalar data in order to reconstruct a phase space is of fundamental importance here. Furthermore, the concept of an attractor as a result of dynamical constraints is exploited. In order to perform noise reduction one needs redundancy and the human voice provides it even within a phoneme, namely the smallest structural unit of speech. Due to several repetitions of a pattern called pitch inside a phoneme, separation between the pure voice signal and the noise is possible, provided the latter is uncorrelated with the former. With a proper parameter tuning, different kinds of noise can be removed. We describe the idea behind the noise reduction algorithm and present applications to vocal pathologies.

  17. Thermodynamics of lunar ilmenite reduction

    NASA Technical Reports Server (NTRS)

    Altenberg, B. H.; Franklin, H. A.; Jones, C. H.

    1993-01-01

    With the prospect of returning to the moon, the development of a lunar occupation would fulfill one of the goals of the Space Exploration Initiative (SEI) of the late 1980's. Processing lunar resources into useful products, such as liquid oxygen for fuel and life support, would be one of many aspects of an active lunar base. ilmenite (FeTiO3) is found on the lunar surface and can be used as a feed stock to produce oxygen. Understanding the various ilmenite-reduction reactions elucidates many processing options. Defining the thermodynamic chemical behavior at equilibrium under various conditions of temperature and pressures can be helpful in specifying optimal operating conditions. Differences between a previous theoretical analysis and experimentally determined results has sparked interest in trying to understand the effect of operating pressure on the hydrogen-reduction-of-ilmenite reaction. Various aspects of this reduction reaction are discussed.

  18. Space Discovery.

    ERIC Educational Resources Information Center

    Blackman, Joan

    1998-01-01

    Describes one teacher's experience taking Space Discovery courses that were sponsored by the United States Space Foundation (USSF). These courses examine the history of space science, theory of orbits and rocketry, the effects of living in outer space on humans, and space weather. (DDR)

  19. How Users Search the Library from a Single Search Box

    ERIC Educational Resources Information Center

    Lown, Cory; Sierra, Tito; Boyer, Josh

    2013-01-01

    Academic libraries are turning increasingly to unified search solutions to simplify search and discovery of library resources. Unfortunately, very little research has been published on library user search behavior in single search box environments. This study examines how users search a large public university library using a prominent, single…

  20. Computerized Literature Searching: An Orientation for the Search Requestor.

    ERIC Educational Resources Information Center

    Fabiano, Emily

    Developed to orient the information seeker to the computerized literature search process, this guide provides background information that will help the user facilitate the search interview and the formation of a search topic, enabling him or her to focus on personal search needs and not on the fundamentals of online searching. Major purposes for…

  1. Variable neighborhood search for reverse engineering of gene regulatory networks.

    PubMed

    Nicholson, Charles; Goodwin, Leslie; Clark, Corey

    2017-01-01

    A new search heuristic, Divided Neighborhood Exploration Search, designed to be used with inference algorithms such as Bayesian networks to improve on the reverse engineering of gene regulatory networks is presented. The approach systematically moves through the search space to find topologies representative of gene regulatory networks that are more likely to explain microarray data. In empirical testing it is demonstrated that the novel method is superior to the widely employed greedy search techniques in both the quality of the inferred networks and computational time.

  2. Citation Searching: Search Smarter & Find More

    ERIC Educational Resources Information Center

    Hammond, Chelsea C.; Brown, Stephanie Willen

    2008-01-01

    The staff at University of Connecticut are participating in Elsevier's Student Ambassador Program (SAmP) in which graduate students train their peers on "citation searching" research using Scopus and Web of Science, two tremendous citation databases. They are in the fourth semester of these training programs, and they are wildly successful: They…

  3. Breast Reduction Surgery

    MedlinePlus

    ... considering breast reduction surgery, consult a board-certified plastic surgeon. It's important to understand what breast reduction ... risk of complications from breast reduction surgery. Your plastic surgeon will likely: Evaluate your medical history and ...

  4. The NASA ADS: Searching, Linking and More

    NASA Technical Reports Server (NTRS)

    Thompson, D. M.; Eichhorn, G.; Accomazzi, A.; Bohlen, E.; Grant, C. S.; Henneken, E.; Kurtz, M.; Murray, S.

    2004-01-01

    The NASA ADS Abstract Service is a NASA-funded project which provides FREE World Wide Web abstract search services. We currently have over 3.6 million references in four databases: 1) Astronomy and Planetary Sciences; 2) Physics and Geophysics; 3) Space Instrumentation; and 4) Astronomy Preprints. Our eleven mirror sites in France, Germany, Japan, Chile, Great Britain, India, Russia, Brazil, Argentina, Korea and China help to provide better global access. Each database contains abstracts from hundreds of journals, publications, colloquia, symposia, proceedings, PhD Theses, and NASA reports. All abstracts can be searched by author, title, or abstract text words.

  5. Fixing Dataset Search

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris

    2014-01-01

    Three current search engines are queried for ozone data at the GES DISC. The results range from sub-optimal to counter-intuitive. We propose a method to fix dataset search by implementing a robust relevancy ranking scheme. The relevancy ranking scheme is based on several heuristics culled from more than 20 years of helping users select datasets.

  6. Using Quick Search.

    ERIC Educational Resources Information Center

    Maxfield, Sandy, Ed.; Kabus, Karl, Ed.

    This document is a guide to the use of Quick Search, a library service that provides access to more than 100 databases which contain references to journal articles and other research materials through two commercial systems--BRS After/Dark and DIALOG's Knowledge Index. The guide is divided into five sections: (1) Using Quick Search; (2) The…

  7. With News Search Engines

    ERIC Educational Resources Information Center

    Gunn, Holly

    2005-01-01

    Although there are many news search engines on the Web, finding the news items one wants can be challenging. Choosing appropriate search terms is one of the biggest challenges. Unless one has seen the article that one is seeking, it is often difficult to select words that were used in the headline or text of the article. The limited archives of…

  8. Spying on Search Strategies

    ERIC Educational Resources Information Center

    Tenopir, Carol

    2004-01-01

    Only the most dedicated super-searchers are motivated to learn and control command systems, like DialogClassic, that rely on the user to input complex search strategies. Infrequent searchers and most end users choose interfaces that do some of the work for them and make the search process appear easy. However, the easier a good interface seems to…

  9. OpenSearch Status

    NASA Technical Reports Server (NTRS)

    Newman, Doug; Silva, Sam; Mitchell, Andrew

    2016-01-01

    We will present an overview of our OpenSearch efforts over the past 6 months. We will discuss our Best Practices and those of CEOS concentrating on the compatibility issues between the two. We will also discuss the state of earth data OpenSearch implementations and their adherence to the standards, extensions and best practices available.

  10. Search for Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Tsubono, K.

    The current status of the experimental search for gravitational waves is reviewed here. The emphasis is on the Japanese TAMA project. We started operation of the TAMA300 laser interferometric detector in 1999, and are now collecting and analyzing observational data to search for gravitational wave signals.

  11. Origins of Coordinate Searching.

    ERIC Educational Resources Information Center

    Kilgour, Frederick G.

    1997-01-01

    Reviews the origins of post-coordinate searching and emphasizes that the focal point should be on the searcher, not on the item being indexed. Highlights include the history of the term information retrieval; edge notched punch cards; the "peek-a-boo" system; the Uniterm system; and using computers to search for information. (LRW)

  12. OAST Space Theme Workshop 1976

    NASA Technical Reports Server (NTRS)

    Sadin, S. R.

    1977-01-01

    Papers that provide a technical foundation including research and technology base candidates for each of six space themes - space power, space industrialization, search for extraterrestrial intelligence, exploration of the solar system, global service, and advanced transportation systems - are presented. The material is mainly intended for further use by workshop participants and NASA elements concerned with space research and technology. While the data presented do not represent official plans or positions, they are part of the process of evolving such plans and positions. The information contained reflects the efforts of workshop participants and should be an aid in the successful implementation and execution of the Agency's near- and far-term advanced technology program.

  13. Visualizing Search Behavior with Adaptive Discriminations

    PubMed Central

    Cook, Robert G.; Qadri, Muhammad A. J.

    2014-01-01

    We examined different aspects of the visual search behavior of a pigeon using an open-ended, adaptive testing procedure controlled by a genetic algorithm. The animal had to accurately search for and peck a gray target element randomly located from among a variable number of surrounding darker and lighter distractor elements. Display composition was controlled by a genetic algorithm involving the multivariate configuration of different parameters or genes (number of distractors, element size, shape, spacing, target brightness, and distractor brightness). Sessions were composed of random displays, testing randomized combinations of these genes, and selected displays, representing the varied descendants of displays correctly identified by the pigeon. Testing a larger number of random displays than done previously, it was found that the bird’s solution to the search task was highly stable and did not change with extensive experience in the task. The location and shape of this attractor was visualized using multivariate behavioral surfaces in which element size and the number of distractors were the most important factors controlling search accuracy and search time. The resulting visualizations of the bird’s search behavior are discussed with reference to the potential of using adaptive, open-ended experimental techniques for investigating animal cognition and their implications for Bond and Kamil’s innovative development of virtual ecologies using an analogous methodology. PMID:24370702

  14. CADC Advanced Search

    NASA Astrophysics Data System (ADS)

    Jenkins, D. N.

    2012-09-01

    The Canadian Astronomy Data Centre's (CADC) Advanced Search web application is a modern search tool to access data across the CADC archives. It allows searching in different units, and is well averse in wild card characters and numeric operations. Search results are displayed in a sortable and filterable manner allowing quick and accurate access to downloadable data. The Advanced Search interface makes extremely good use of the Astronomical Data Query Language (ADQL) to scour the Common Archive Observation Model (CAOM) Table Access Protocol (TAP) query service and the vast CADC Archive Data (AD) storage system. A new tabular view of the query form and the results data makes it easy to view the query, then return to the query form to make further changes, or, alternatively, filter the data from the paginated table. Results are displayed using a rich, open-source, JavaScript-based VOTable viewer called voview.

  15. Intermittent search strategies

    NASA Astrophysics Data System (ADS)

    Bénichou, O.; Loverdo, C.; Moreau, M.; Voituriez, R.

    2011-01-01

    This review examines intermittent target search strategies, which combine phases of slow motion, allowing the searcher to detect the target, and phases of fast motion during which targets cannot be detected. It is first shown that intermittent search strategies are actually widely observed at various scales. At the macroscopic scale, this is, for example, the case of animals looking for food; at the microscopic scale, intermittent transport patterns are involved in a reaction pathway of DNA-binding proteins as well as in intracellular transport. Second, generic stochastic models are introduced, which show that intermittent strategies are efficient strategies that enable the minimization of search time. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature. Last, beyond these modeling aspects, it is proposed that intermittent strategies could also be used in a broader context to design and accelerate search processes.

  16. Needle Federated Search Engine

    SciTech Connect

    2009-12-01

    The Idaho National Laboratory (INL) has combined a number of technologies, tools, and resources to accomplish a new means of federating search results. The resulting product is a search engine called Needle, an open-source-based tool that the INL uses internally for researching across a wide variety of information repositories. Needle has a flexible search interface that allows end users to point at any available data source. A user can select multiple sources such as commercial databases (Web of Science, Engineering Index), external resources (WorldCat, Google Scholar), and internal corporate resources (email, document management system, library collections) in a single interface with one search query. In the future, INL hopes to offer this open-source engine to the public. This session will outline the development processes for making Needle™s search interface and simplifying the federation of internal and external data sources.

  17. Lymphedema Risk Reduction Practices

    MedlinePlus

    ... now! Position Paper: Lymphedema Risk Reduction Practices Category: Position Papers Tags: Risks Archives Treatment risk reduction garments surgery obesity infection blood pressure trauma morbid obesity body weight ...

  18. Space Station

    NASA Technical Reports Server (NTRS)

    Anderton, D. A.

    1985-01-01

    The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited.

  19. The importance of search strategy for finding targets in open terrain.

    PubMed

    Riggs, Charlotte A; Cornes, Katherine; Godwin, Hayward J; Liversedge, Simon P; Guest, Richard; Donnelly, Nick

    2017-01-01

    A number of real-world search tasks (i.e. police search, detection of improvised explosive devices (IEDs)) require searchers to search exhaustively across open ground. In the present study, we simulated this problem by asking individuals (Experiments 1a and 1b) and dyads (Experiment 2) to search for coin targets pseudo-randomly located in a bounded area of open grassland terrain. In Experiment 1a, accuracy, search time, and the route used to search an area were measured. Participants tended to use an 'S'-shaped pattern with a common width of search lane. Increased accuracy was associated with slower, but also variable, search speed, though only when participants moved along the length (as opposed to across the width) of the search area. Experiment 1b varied the number of targets available within the bounded search area and in doing so varied target prevalence and density. The results confirmed that the route taken in Experiment 1a generalizes across variations in target prevalence/density. In Experiment 2, accuracy, search time, and the search strategy used by dyads was measured. While dyads were more accurate than individuals, dyads that opted to conduct two independent searches were more accurate than those who opted to split the search space. The implications of these results for individuals and dyads when searching for targets in open space are discussed.

  20. Custom Search Engines: Tools & Tips

    ERIC Educational Resources Information Center

    Notess, Greg R.

    2008-01-01

    Few have the resources to build a Google or Yahoo! from scratch. Yet anyone can build a search engine based on a subset of the large search engines' databases. Use Google Custom Search Engine or Yahoo! Search Builder or any of the other similar programs to create a vertical search engine targeting sites of interest to users. The basic steps to…

  1. Search for Life in the Solar System and Beyond: A Unifying Vision for NASA Science Through 2050

    NASA Astrophysics Data System (ADS)

    Hammel, H. B.; Mountain, M.; Grunsfeld, J. M.

    2017-02-01

    The search for life beyond Earth defines the frontier for our generation. The search will require a multi-dimensional space where scientists, technologists, engineers, entrepreneurs, and educators can jointly collaborate, explore, and innovate.

  2. Intelligent perturbation algorithms to space scheduling optimization

    NASA Technical Reports Server (NTRS)

    Kurtzman, Clifford R.

    1991-01-01

    The limited availability and high cost of crew time and scarce resources make optimization of space operations critical. Advances in computer technology coupled with new iterative search techniques permit the near optimization of complex scheduling problems that were previously considered computationally intractable. Described here is a class of search techniques called Intelligent Perturbation Algorithms. Several scheduling systems which use these algorithms to optimize the scheduling of space crew, payload, and resource operations are also discussed.

  3. Space station

    NASA Technical Reports Server (NTRS)

    Stewart, Donald F.; Hayes, Judith

    1989-01-01

    The history of American space flight indicates that a space station is the next logical step in the scientific pursuit of greater knowledge of the universe. The Space Station and its complement of space vehicles, developed by NASA, will add new dimensions to an already extensive space program in the United States. The Space Station offers extraordinary benefits for a comparatively modest investment (currently estimated at one-ninth the cost of the Apollo Program). The station will provide a permanent multipurpose facility in orbit necessary for the expansion of space science and technology. It will enable significant advancements in life sciences research, satellite communications, astronomy, and materials processing. Eventually, the station will function in support of the commercialization and industrialization of space. Also, as a prerequisite to manned interplanetary exploration, the long-duration space flights typical of Space Station missions will provide the essential life sciences research to allow progressively longer human staytime in space.

  4. Search for solar axions

    NASA Astrophysics Data System (ADS)

    Newman, Seth Aaron

    Peccei and Quinn proposed an elegant solution for restoring CP symmetry to the QCD Lagrangian [37]. This method includes an additional global U(1) symmetry included in the QCD Lagrangian which is spontaneously broken at a high energy scale, fa. Breaking the symmetry generates a Nambu-Goldstone boson called the axion. Although there are various detection mechanisms that search for the axion, this thesis focuses on the the axio-electric effect. The axio-electric is similar to the photo-electric effect in that an axion is absorbed by an atom which subsequently emits an electron. The electron's energy is equivalent to the incoming axion energy minus the binding energy. The higher shell electrons immediately replenish the missing binding energy yielding a single energy peak at the incoming axion's energy. The 14.4 keV M1 transition of 57Fe is one possible axion source. The development of an optimum trigger algorithm has lowered the threshold for analysis in TeO2 bolometers to a few keV making an axion signature accessible to CUORE related R&D experiments such as the Chinese Crystal Validation Runs (CCVR) and Three Towers Test (TTT). These TeO2 crystal detectors have masses 750 and 790 grams, respectively. Each crystal has a stabilization heater and a germanium thermometer attached to its surface by an epoxy glue. The two previous experiments are R&D tests for the upcoming larger experiment, CUORE. CUORE will be made of 988 TeO2 crystals arranged in 19 towers with 13 floors each, each floor with 4 detectors. This thesis examined 87.01 kg·days of Three Towers data for an axion signal. A peak is observed in the region of interest with a statistical significance less than 1sigma over the expected background fluctuations, yielding a total background rate of 0.185 +/- 0.001 (Stat.) +/- 0.006 (Syst.) Counts/kg/day at 95% C.L. This places an experimental limit on the coupling constant fa of f a (S = 0.50) ≥ 1.16 x 106 GeV at 95% C.L. Projecting the TTT result to the CUORE

  5. Space 2000 Symposium

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The purpose of the Space 2000 Symposium is to present the creativity and achievements of key figures of the 20th century. It offers a retrospective discussion on space exploration. It considers the future of the enterprise, and the legacy that will be left for future generations. The symposium includes panel discussions, smaller session meetings with some panelists, exhibits, and displays. The first session entitled "From Science Fiction to Science Facts" commences after a brief overview of the symposium. The panel discussions include talks on space exploration over many decades, and the missions of the millennium to search for life on Mars. The second session, "Risks and Rewards of Human Space Exploration," focuses on the training and health risks that astronauts face on their exploratory mission to space. Session three, "Messages and Messengers Informing and Inspire Space Exploration and the Public," focuses on the use of TV medium by educators and actors to inform and inspire a wide variety of audiences with adventures of space exploration. Session four, "The Legacy of Carl Sagan," discusses the influences made by Sagan to scientific research and the general public. In session five, "Space Exploration for a new Generation," two student speakers and the NASA Administrator Daniel S. Goldin address the group. Session six, "Destiny or Delusion? -- Humankind's Place in the Cosmos," ends the symposium with issues of space exploration and some thought provoking questions. Some of these issues and questions are: what will be the societal implications if we discover the origin of the universe, stars, or life; what will be the impact if scientists find clear evidence of life outside the domains of the Earth; should there be limits to what humans can or should learn; and what visionary steps should space-faring people take now for future generations.

  6. Improving Search Engine Reliability

    NASA Astrophysics Data System (ADS)

    Pruthi, Jyoti; Kumar, Ela

    2010-11-01

    Search engines on the Internet are used daily to access and find information. While these services are providing an easy way to find information globally, they are also suffering from artificially created false results. This paper describes two techniques that are being used to manipulate the search engines: spam pages (used to achieve higher rankings on the result page) and cloaking (used to feed falsified data into search engines). This paper also describes two proposed methods to fight this kind of misuse, algorithms for both of the formerly mentioned cases of spamdexing.

  7. ReSEARCH: A Requirements Search Engine

    DTIC Science & Technology

    2008-04-23

    formally specify the meaning and domain of their requirements. Our goal in the research presented here is to address these concerns by designing a...synonymous. auto engine bonnet tyres lorry boot car emissions hood make model trunk make hidden Markov model emissions normalize Synonymy Problem Polysemy ...links as well • attempts to identify topic clusters related to search • find experts within these topics to “seed” the rank of some websites as

  8. A bimodal search strategy for SETI

    NASA Technical Reports Server (NTRS)

    Gulkis, S.; Olsen, E. T.; Tarter, J.

    1980-01-01

    The search strategy and resultant observational plan which was developed to carry out a comprehensive Search for Extraterrestrial Intelligence (SETI) over that portion of the electromagnetic spectrum known as the terrestrial microwave window is described. The limiting sensitivity achieved was parameterized and calculated for Deep Space Network antennas as well as several radio astronomy observatories. A brief description of the instrumentation to be employed in the search and the classes of signals to be looked for is given. One observational goal is to survey the entire sky over a wide range of frequency to a relatively constant flux level. This survey ensures that all potential life sites are observed to some limiting equivalent isotropic radiated power depending upon their distance. A second goal is to survey a set of potential transmission sites selected a priori to be especially promising, achieving very high sensitivity over a smaller range of frequency.

  9. Genetic algorithms as global random search methods

    NASA Technical Reports Server (NTRS)

    Peck, Charles C.; Dhawan, Atam P.

    1995-01-01

    Genetic algorithm behavior is described in terms of the construction and evolution of the sampling distributions over the space of candidate solutions. This novel perspective is motivated by analysis indicating that the schema theory is inadequate for completely and properly explaining genetic algorithm behavior. Based on the proposed theory, it is argued that the similarities of candidate solutions should be exploited directly, rather than encoding candidate solutions and then exploiting their similarities. Proportional selection is characterized as a global search operator, and recombination is characterized as the search process that exploits similarities. Sequential algorithms and many deletion methods are also analyzed. It is shown that by properly constraining the search breadth of recombination operators, convergence of genetic algorithms to a global optimum can be ensured.

  10. Genetic algorithms as global random search methods

    NASA Technical Reports Server (NTRS)

    Peck, Charles C.; Dhawan, Atam P.

    1995-01-01

    Genetic algorithm behavior is described in terms of the construction and evolution of the sampling distributions over the space of candidate solutions. This novel perspective is motivated by analysis indicating that that schema theory is inadequate for completely and properly explaining genetic algorithm behavior. Based on the proposed theory, it is argued that the similarities of candidate solutions should be exploited directly, rather than encoding candidate solution and then exploiting their similarities. Proportional selection is characterized as a global search operator, and recombination is characterized as the search process that exploits similarities. Sequential algorithms and many deletion methods are also analyzed. It is shown that by properly constraining the search breadth of recombination operators, convergence of genetic algorithms to a global optimum can be ensured.

  11. A novel visualization model for web search results.

    PubMed

    Nguyen, Tien N; Zhang, Jin

    2006-01-01

    This paper presents an interactive visualization system, named WebSearchViz, for visualizing the Web search results and acilitating users' navigation and exploration. The metaphor in our model is the solar system with its planets and asteroids revolving around the sun. Location, color, movement, and spatial distance of objects in the visual space are used to represent the semantic relationships between a query and relevant Web pages. Especially, the movement of objects and their speeds add a new dimension to the visual space, illustrating the degree of relevance among a query and Web search results in the context of users' subjects of interest. By interacting with the visual space, users are able to observe the semantic relevance between a query and a resulting Web page with respect to their subjects of interest, context information, or concern. Users' subjects of interest can be dynamically changed, redefined, added, or deleted from the visual space.

  12. Space Power

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Appropriate directions for the applied research and technology programs that will develop space power systems for U.S. future space missions beyond 1995 are explored. Spacecraft power supplies; space stations, space power reactors, solar arrays, thermoelectric generators, energy storage, and communication satellites are among the topics discussed.

  13. Themed Space

    ERIC Educational Resources Information Center

    Lynch, Christopher O.

    2010-01-01

    This article presents a classroom activity that introduces students to the concept of themed space. Students learn to think critically about the spaces they encounter on a regular basis by analyzing existing spaces and by working in groups to create their own themed space. This exercise gives students the chance to see the relevance of critical…

  14. Space colonization.

    PubMed

    2002-12-01

    NASA interest in colonization encompasses space tourism; space exploration; space bases in orbit, at L1, on the Moon, or on Mars; in-situ resource utilization; and planetary terraforming. Activities progressed during 2002 in areas such as Mars colonies, hoppers, and biomass; space elevators and construction; and in-situ consumables.

  15. Characterization of organics, microorganisms, desert soils, and Mars-like soils by thermal volatilization coupled to mass spectrometry and their implications for the search for organics on Mars by Phoenix and future space missions.

    PubMed

    Navarro-González, Rafael; Iñiguez, Enrique; de la Rosa, José; McKay, Christopher P

    2009-10-01

    A key goal for astrobiology is the search for evidence of life on Mars. Because liquid water is a fundamental environmental requirement for life, the recent set of missions to Mars have focused on a strategy known as "follow the water." Since life is made of organic molecules, a logical next step is "follow the organics." However, organics are expected to be present at very low levels on Mars, which would make their detection challenging. Viking was unable to detect organics at parts per billion (ppb), but the effective upper limit could be higher due to the low efficiency of the thermal volatilization (TV) step in releasing organics. Due to its ease of use, TV is still the method selected for current and future NASA and ESA missions. Here, we show that when organics are present in the soil at levels above 1500 parts per million (ppm), there are several characteristic organic fragments detected by TV-mass spectrometry; however, when the levels are below <150 ppm, TV oxidizes them, and no organic fragments are released. Instead, nitric oxide (NO) is produced and can be used to determine quantitatively the organic content if the C/N ratio is determined. Any atmospheric NO sorbed or mineral nitrogen (e.g., nitrates) present in the soil would release NO by TV at distinctive temperature regimes that would not overlap with the organic nitrogen source. Therefore, we suggest that monitoring NO provides the best chance for Phoenix and other future Mars missions to detect nitrogen-containing organics in the soil or ice.

  16. Searching Sociological Abstracts.

    ERIC Educational Resources Information Center

    Kerbel, Sandra Sandor

    1981-01-01

    Describes the scope, content, and retrieval characteristics of Sociological Abstracts, an online database of literature in the social sciences. Sample searches are displayed, and the strengths and weaknesses of the database are summarized. (FM)

  17. Automated search for supernovae

    SciTech Connect

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  18. Searching for Surgeons

    MedlinePlus

    ... Cancer Programs Trauma Centers Education Institutes Breast Centers Bariatric Surgery Centers ACS NSQIP Hospitals Search Member Services Member ... Invoices Quality and Safety Conference Bariatrics Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program Metabolic and Bariatric ...

  19. Improving Search Algorithms by Using Intelligent Coordinates

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.; Tumer, Kagan; Bandari, Esfandiar

    2004-01-01

    We consider algorithms that maximize a global function G in a distributed manner, using a different adaptive computational agent to set each variable of the underlying space. Each agent eta is self-interested; it sets its variable to maximize its own function g (sub eta). Three factors govern such a distributed algorithm's performance, related to exploration/exploitation, game theory, and machine learning. We demonstrate how to exploit alI three factors by modifying a search algorithm's exploration stage: rather than random exploration, each coordinate of the search space is now controlled by a separate machine-learning-based player engaged in a noncooperative game. Experiments demonstrate that this modification improves simulated annealing (SA) by up to an order of magnitude for bin packing and for a model of an economic process run over an underlying network. These experiments also reveal interesting small-world phenomena.

  20. Space Industry

    DTIC Science & Technology

    2006-01-01

    invest in and support commercial efforts. In testimony before the House Committee on Space and Aeronautics in April of 2005, Elon Musk provided the...Response Launch Vehicle. Space Daily. Retrieved April 9, 2006 from www.spacedaily.com. 81 Musk , Elon (2005, April 20). Commercialization of Space...Space Transportation Policy. (2006, January 5). Retrieved May 30, 2006 from http://www.ostp.gov/html/SpaceTransFactSheetJan2005.pdf. 86 Musk , Elon

  1. Radioastronomical Searches for Instellar Biomolecules

    NASA Technical Reports Server (NTRS)

    Kuan, Y.-J.; Huang, H.-C.; Charnley, S. B.; Markwick, A.; Botta, O.; Ehrenfreund, P.; Kisiel, Z.; Butner, H. M.

    2003-01-01

    Impacts of comets and asteroids could have delivered large amounts of organic matter to the early Earth. to retain a significant interstellar signature; observations of recent bright comets indicate that they have a molecular inventory consistent with their ices being largely unmodified interstellar material. Many simple organic molecules with biochemical significance observed in circumstellar envelopes and in molecular clouds, similar to that from which the Solar System formed, may have acted as the precursors of the more complex organics found in meteorites. Therefore, there is potentially a strong link between interstellar organics and prebiotic chemical evolution. Radioastronomical observations, particularly at millimeter wavelengths, allow us to determine the chemical composition and characteristics of the molecular inventory in interstellar space. Here we report some of our recent results from extensive astronomical searches for astrobiologically-important interstellar organics.

  2. Piled-Slab Searches

    DTIC Science & Technology

    2006-12-01

    tinuously as one moves away from the origin (Figure 1). Because such a search is both strategically optimal and locally random, we will refer to it as SOLR ...approximating the inverted cup with a solid composed of n piled slabs. The resulting detection proba- bility will, of course, be smaller than the SOLR ...total effort density in the annulus between Ri−1 and Ri (Figure 2). The total Figure 1. The inverted SOLR cup has the greatest search effort density at

  3. Stride search: A general algorithm for storm detection in high-resolution climate data

    SciTech Connect

    Bosler, Peter A.; Roesler, Erika L.; Taylor, Mark A.; Mundt, Miranda R.

    2016-04-13

    This study discusses the problem of identifying extreme climate events such as intense storms within large climate data sets. The basic storm detection algorithm is reviewed, which splits the problem into two parts: a spatial search followed by a temporal correlation problem. Two specific implementations of the spatial search algorithm are compared: the commonly used grid point search algorithm is reviewed, and a new algorithm called Stride Search is introduced. The Stride Search algorithm is defined independently of the spatial discretization associated with a particular data set. Results from the two algorithms are compared for the application of tropical cyclone detection, and shown to produce similar results for the same set of storm identification criteria. Differences between the two algorithms arise for some storms due to their different definition of search regions in physical space. The physical space associated with each Stride Search region is constant, regardless of data resolution or latitude, and Stride Search is therefore capable of searching all regions of the globe in the same manner. Stride Search's ability to search high latitudes is demonstrated for the case of polar low detection. Wall clock time required for Stride Search is shown to be smaller than a grid point search of the same data, and the relative speed up associated with Stride Search increases as resolution increases.

  4. Stride search: A general algorithm for storm detection in high-resolution climate data

    DOE PAGES

    Bosler, Peter A.; Roesler, Erika L.; Taylor, Mark A.; ...

    2016-04-13

    This study discusses the problem of identifying extreme climate events such as intense storms within large climate data sets. The basic storm detection algorithm is reviewed, which splits the problem into two parts: a spatial search followed by a temporal correlation problem. Two specific implementations of the spatial search algorithm are compared: the commonly used grid point search algorithm is reviewed, and a new algorithm called Stride Search is introduced. The Stride Search algorithm is defined independently of the spatial discretization associated with a particular data set. Results from the two algorithms are compared for the application of tropical cyclonemore » detection, and shown to produce similar results for the same set of storm identification criteria. Differences between the two algorithms arise for some storms due to their different definition of search regions in physical space. The physical space associated with each Stride Search region is constant, regardless of data resolution or latitude, and Stride Search is therefore capable of searching all regions of the globe in the same manner. Stride Search's ability to search high latitudes is demonstrated for the case of polar low detection. Wall clock time required for Stride Search is shown to be smaller than a grid point search of the same data, and the relative speed up associated with Stride Search increases as resolution increases.« less

  5. Sterile Neutrino Search with MINOS

    SciTech Connect

    Devan, Alena V.

    2015-08-01

    MINOS, Main Injector Neutrino Oscillation Search, is a long-baseline neutrino oscillation experiment in the NuMI muon neutrino beam at the Fermi National Accelerator Laboratory in Batavia, IL. It consists of two detectors, a near detector positioned 1 km from the source of the beam and a far detector 734 km away in Minnesota. MINOS is primarily designed to observe muon neutrino disappearance resulting from three flavor oscillations. The Standard Model of Particle Physics predicts that neutrinos oscillate between three active flavors as they propagate through space. This means that a muon-type neutrino has a certain probability to later interact as a different type of neutrino. In the standard picture, the neutrino oscillation probabilities depend only on three neutrino flavors and two mass splittings, Δm2. An anomaly was observed by the LSND and MiniBooNE experiments that suggests the existence of a fourth, sterile neutrino flavor that does not interact through any of the known Standard Model interactions. Oscillations into a theoretical sterile flavor may be observed by a deficit in neutral current interactions in the MINOS detectors. A distortion in the charged current energy spectrum might also be visible if oscillations into the sterile flavor are driven by a large mass-squared difference, ms2 ~ 1 eV2. The results of the 2013 sterile neutrino search are presented here.

  6. National Space Agencies vs. Commercial Space: Towards Improved Space Safety

    NASA Astrophysics Data System (ADS)

    Pelton, J.

    2013-09-01

    assume that thiscondition will not change. This seems particularly true for high profile, multi-billion dollar programs.The second part of the paper focuses on new commercial space programs that appear to be undertaken in a less restrictive manner; i.e. outside the constraints of politically-driven national space policies. Here the drivers—even within international consortia—seem to be on reliable performance and commercial return. Since sustained accident-free performance is critical to commercial programs very existence and profitability, the inherent role of safety in commercial space industry would seem clear. The question of prime interest for this paper is whether or not it might be possible for smaller and more focused commercial space entities, free from the constraints of space agency organizational and political constraints, to be more "risk adverse" and thus be more nimble in designing "safe" vehicles? If so how can this "safety first" corporate philosophy and management practice be detected and even objectively measured? Could, in the future, risk reduction at the level of design, quality verification, etc., be objectively measured?

  7. Space Resources Roundtable 2

    NASA Technical Reports Server (NTRS)

    Ignatiev, A.

    2000-01-01

    Economy in CisLunar Space. Our Lunar Destiny: Creating a Lunar Economy. Cost-Effective Approaches to Lunar Passenger Transportation. Lunar Mineral Resources: Extraction and Application. Space Resources Development - The Link Between Human Exploration and the Long-term Commercialization of Space. Toward a More Comprehensive Evaluation of Space Information. Development of Metal Casting Molds by Sol-Gel Technology Using Planetary Resources. A New Concept in Planetary Exploration: ISRU with Power Bursts. Bold Space Ventures Require Fervent Public Support. Hot-pressed Iron from Lunar Soil. The Lunar Dust Problem: A Possible Remedy. Considerations on Use of Lunar Regolith in Lunar Constructions. Experimental Study on Water Production by Hydrogen Reduction of Lunar Soil Simulant in a Fixed Bed Reactor.

  8. Model reduction of flexible manipulators

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Xu, Yangsheng; Chen, C. S.

    1992-06-01

    Flexible manipulators can be characterized by a dynamic model with a large number of vibration modes, and the use of the model in the model-based control schemes requires reduction of model order. Balanced truncation is an effective method for model reduction of asymptotically stable systems by transforming the states to a coordinate system in which the controllability and observability Gramians are equal and diagonal, and eliminating the states which contribute weakly to the input-output map. An elastic flexible manipulator, however, is a marginally stable system and thus the balanced truncation method can not be directly applied. Herein, a method is presented of reducing the order of a marginally stable system based on the fact that translation transformations in the frequency domain preserve input-output properties of the system. The successful application is addressed of the method to model reduction of flexible manipulators with infinite-dimensional for finite-dimensional model. The method is also applicable for any other marginally stable model, such as elastic space trusswork and multi-dimensional space vehicle structure.

  9. Global OpenSearch

    NASA Astrophysics Data System (ADS)

    Newman, D. J.; Mitchell, A. E.

    2015-12-01

    At AGU 2014, NASA EOSDIS demonstrated a case-study of an OpenSearch framework for Earth science data discovery. That framework leverages the IDN and CWIC OpenSearch API implementations to provide seamless discovery of data through the 'two-step' discovery process as outlined by the Federation for Earth Sciences (ESIP) OpenSearch Best Practices. But how would an Earth Scientist leverage this framework and what are the benefits? Using a client that understands the OpenSearch specification and, for further clarity, the various best practices and extensions, a scientist can discovery a plethora of data not normally accessible either by traditional methods (NASA Earth Data Search, Reverb, etc) or direct methods (going to the source of the data) We will demonstrate, via the CWICSmart web client, how an earth scientist can access regional data on a regional phenomena in a uniform and aggregated manner. We will demonstrate how an earth scientist can 'globalize' their discovery. You want to find local data on 'sea surface temperature of the Indian Ocean'? We can help you with that. 'European meteorological data'? Yes. 'Brazilian rainforest satellite imagery'? That too. CWIC allows you to get earth science data in a uniform fashion from a large number of disparate, world-wide agencies. This is what we mean by Global OpenSearch.

  10. Improved Search Techniques

    NASA Technical Reports Server (NTRS)

    Albornoz, Caleb Ronald

    2012-01-01

    Thousands of millions of documents are stored and updated daily in the World Wide Web. Most of the information is not efficiently organized to build knowledge from the stored data. Nowadays, search engines are mainly used by users who rely on their skills to look for the information needed. This paper presents different techniques search engine users can apply in Google Search to improve the relevancy of search results. According to the Pew Research Center, the average person spends eight hours a month searching for the right information. For instance, a company that employs 1000 employees wastes $2.5 million dollars on looking for nonexistent and/or not found information. The cost is very high because decisions are made based on the information that is readily available to use. Whenever the information necessary to formulate an argument is not available or found, poor decisions may be made and mistakes will be more likely to occur. Also, the survey indicates that only 56% of Google users feel confident with their current search skills. Moreover, just 76% of the information that is available on the Internet is accurate.

  11. A SEARCH FOR SATELLITES AROUND CERES

    SciTech Connect

    Bieryla, A.; Parker, J. Wm.; Young, E. F.; Stern, S. A.; McFadden, L. A.; Russell, C. T.; Sykes, M. V.; Gladman, B.

    2011-06-15

    We conducted a satellite search around the dwarf planet 1 Ceres using Hubble Space Telescope and ground-based Palomar data. No candidate objects were found orbiting Ceres in its entire stability region down to {approx}500 km from the surface of Ceres. Assuming a satellite would have the same albedo as Ceres, which has a visual geometric albedo of 0.07-0.10, our detection limit is sensitive to satellites larger than 1-2 km in diameter.

  12. A Theoretical Search for Supervelocity Semiconductors

    DTIC Science & Technology

    1992-10-01

    Monte Carlo simulations in order to study pseudomorphic devices, real space transfer structures, and submicron MOSFETs , and 4) search for new quantum...collector-drain leakage currents, and 3) a collector-up device configuration to reduce parasitic capacitance and to facilitate proper arrangement of the...in silicon devices For the past fifteen years, the silicon MOSFET industry has been dealing increasingly with prob- lems related to hot electron

  13. Improving the efficiency of branch-and-bound complete-search NMR assignment using the symmetry of molecules and spectra

    NASA Astrophysics Data System (ADS)

    Bernal, Andrés; Castillo, Andrés M.; González, Fabio; Patiny, Luc; Wist, Julien

    2015-02-01

    Nuclear magnetic resonance (NMR) assignment of small molecules is presented as a typical example of a combinatorial optimization problem in chemical physics. Three strategies that help improve the efficiency of solution search by the branch and bound method are presented: 1. reduction of the size of the solution space by resort to a condensed structure formula, wherein symmetric nuclei are grouped together; 2. partitioning of the solution space based on symmetry, that becomes the basis for an efficient branching procedure; and 3. a criterion of selection of input restrictions that leads to increased gaps between branches and thus faster pruning of non-viable solutions. Although the examples chosen to illustrate this work focus on small-molecule NMR assignment, the results are generic and might help solving other combinatorial optimization problems.

  14. Improving the efficiency of branch-and-bound complete-search NMR assignment using the symmetry of molecules and spectra

    SciTech Connect

    Bernal, Andrés; Patiny, Luc; Castillo, Andrés M.; González, Fabio; Wist, Julien

    2015-02-21

    Nuclear magnetic resonance (NMR) assignment of small molecules is presented as a typical example of a combinatorial optimization problem in chemical physics. Three strategies that help improve the efficiency of solution search by the branch and bound method are presented: 1. reduction of the size of the solution space by resort to a condensed structure formula, wherein symmetric nuclei are grouped together; 2. partitioning of the solution space based on symmetry, that becomes the basis for an efficient branching procedure; and 3. a criterion of selection of input restrictions that leads to increased gaps between branches and thus faster pruning of non-viable solutions. Although the examples chosen to illustrate this work focus on small-molecule NMR assignment, the results are generic and might help solving other combinatorial optimization problems.

  15. Space debris measurement program at Phillips Laboratory

    NASA Technical Reports Server (NTRS)

    Dao, Phan D.; Mcnutt, Ross T.

    1992-01-01

    Ground-based optical sensing was identified as a technique for measuring space debris complementary to radar in the critical debris size range of 1 to 10 cm. The Phillips Laboratory is building a staring optical sensor for space debris measurement and considering search and track optical measurement at additional sites. The staring sensor is implemented in collaboration with Wright Laboratory using the 2.5 m telescope at Wright Patterson AFB, Dayton, Ohio. The search and track sensor is designed to detect and track orbital debris in tasked orbits. A progress report and a discussion of sensor performance and search and track strategies will be given.

  16. Space prospects. [european space programs

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A strategy for keeping the Common Market's space effort independent of and competitive with NASA and the space shuttle is discussed. Limited financing is the chief obstacle to this. Proposals include an outer space materials processing project and further development of the Ariane rocket. A manned space program is excluded for the foreseeable future.

  17. Air & Space Power Journal. Volume 24, Number 3, Fall 2010

    DTIC Science & Technology

    2010-01-01

    Chapters in book 2 include the race to the moon, the space shuttle, space sta- tions, expendable booster development, the search for extraterrestrial ...response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and...it is your responsibility to re­ search and report it. Candor and objectivity alone will prob­ ably help catch 90 percent of the issues be­ fore

  18. Automated reduction of instantaneous flow field images

    NASA Technical Reports Server (NTRS)

    Reynolds, G. A.; Short, M.; Whiffen, M. C.

    1987-01-01

    An automated data reduction system for the analysis of interference fringe patterns obtained using the particle image velocimetry technique is described. This system is based on digital image processing techniques that have provided the flexibility and speed needed to obtain more complete automation of the data reduction process. As approached here, this process includes scanning/searching for data on the photographic record, recognition of fringe patterns of sufficient quality, and, finally, analysis of these fringes to determine a local measure of the velocity magnitude and direction. The fringe analysis as well as the fringe image recognition are based on full frame autocorrelation techniques using parallel processing capabilities.

  19. Look before you seek: Preview adds a fixed benefit to all searches

    PubMed Central

    Sunder, Sricharan; Arun, S. P.

    2016-01-01

    Knowing in advance what to look for speeds up search, but how this knowledge guides search is poorly understood. The little available evidence suggests that previewing the target produces larger reductions in search times for harder searches. To investigate this issue further, we performed seven experiments in which subjects searched for an oddball target after previewing the target, distracter, or an unrelated square. Consistent with previous studies, harder searches showed bigger reductions in search time for an informative preview. However, the same data replotted using the reciprocal of search time showed a remarkably different result: The informative preview showed a fixed additive increase in reciprocal search time across all searches regardless of difficulty. This is a nontrivial outcome because it cannot be explained using a simple relationship between search times in the informative and uninformative preview conditions. We interpret our findings by proposing that the reciprocal of search time reflects the strength of an underlying accumulating signal related to the distinctiveness or salience of the target over the distracters and that preview additively increases this signal for all searches. This in turn implies that the top-down signals related to target preview and bottom-up signals related to target-distracter salience sum linearly. PMID:27919099

  20. Local reduction in physics

    NASA Astrophysics Data System (ADS)

    Rosaler, Joshua

    2015-05-01

    A conventional wisdom about the progress of physics holds that successive theories wholly encompass the domains of their predecessors through a process that is often called "reduction." While certain influential accounts of inter-theory reduction in physics take reduction to require a single "global" derivation of one theory's laws from those of another, I show that global reductions are not available in all cases where the conventional wisdom requires reduction to hold. However, I argue that a weaker "local" form of reduction, which defines reduction between theories in terms of a more fundamental notion of reduction between models of a single fixed system, is available in such cases and moreover suffices to uphold the conventional wisdom. To illustrate the sort of fixed-system, inter-model reduction that grounds inter-theoretic reduction on this picture, I specialize to a particular class of cases in which both models are dynamical systems. I show that reduction in these cases is underwritten by a mathematical relationship that follows a certain liberalized construal of Nagel/Schaffner reduction, and support this claim with several examples. Moreover, I show that this broadly Nagelian analysis of inter-model reduction encompasses several cases that are sometimes cited as instances of the "physicist's" limit-based notion of reduction.

  1. Children's Search Engines from an Information Search Process Perspective.

    ERIC Educational Resources Information Center

    Broch, Elana

    2000-01-01

    Describes cognitive and affective characteristics of children and teenagers that may affect their Web searching behavior. Reviews literature on children's searching in online public access catalogs (OPACs) and using digital libraries. Profiles two Web search engines. Discusses some of the difficulties children have searching the Web, in the…

  2. Dark Matter searches: the nightmare scenario

    NASA Astrophysics Data System (ADS)

    Bertone, Gianfranco; Cumberbatch, Daniel; Ruiz de Austri, Roberto; Trotta, Roberto

    2012-01-01

    The unfortunate case where the Large Hadron Collider (LHC) fails to discover physics Beyond the Standard Model (BSM) is sometimes referred to as the ``Nightmare scenario'' of particle physics. We study the consequences of this hypothetical scenario for Dark Matter (DM), in the framework of the constrained Minimal Supersymmetric Standard Model (cMSSM). We evaluate the surviving regions of the cMSSM parameter space after null searches at the LHC, using several different LHC configurations, and study the consequences for DM searches with ton-scale direct detectors and the IceCube neutrino telescope. We demonstrate that ton-scale direct detection experiments will be able to conclusively probe the cMSSM parameter space that would survive null searches at the LHC with 100 fb-1 of integrated luminosity at 14 TeV. We also demonstrate that IceCube (80 strings plus DeepCore) will be able to probe as much as simeq 17% of the currently favoured parameter space after 5 years of observation.

  3. Dark Matter searches: the nightmare scenario

    SciTech Connect

    Bertone, Gianfranco; Cumberbatch, Daniel; Austri, Roberto Ruiz de

    2012-01-01

    The unfortunate case where the Large Hadron Collider (LHC) fails to discover physics Beyond the Standard Model (BSM) is sometimes referred to as the ''Nightmare scenario'' of particle physics. We study the consequences of this hypothetical scenario for Dark Matter (DM), in the framework of the constrained Minimal Supersymmetric Standard Model (cMSSM). We evaluate the surviving regions of the cMSSM parameter space after null searches at the LHC, using several different LHC configurations, and study the consequences for DM searches with ton-scale direct detectors and the IceCube neutrino telescope. We demonstrate that ton-scale direct detection experiments will be able to conclusively probe the cMSSM parameter space that would survive null searches at the LHC with 100 fb{sup −1} of integrated luminosity at 14 TeV. We also demonstrate that IceCube (80 strings plus DeepCore) will be able to probe as much as ≅ 17% of the currently favoured parameter space after 5 years of observation.

  4. Modernizing quantum annealing using local searches

    NASA Astrophysics Data System (ADS)

    Chancellor, Nicholas

    2017-02-01

    I describe how real quantum annealers may be used to perform local (in state space) searches around specified states, rather than the global searches traditionally implemented in the quantum annealing algorithm (QAA). Such protocols will have numerous advantages over simple quantum annealing. By using such searches the effect of problem mis-specification can be reduced, as only energy differences between the searched states will be relevant. The QAA is an analogue of simulated annealing, a classical numerical technique which has now been superseded. Hence, I explore two strategies to use an annealer in a way which takes advantage of modern classical optimization algorithms. Specifically, I show how sequential calls to quantum annealers can be used to construct analogues of population annealing and parallel tempering which use quantum searches as subroutines. The techniques given here can be applied not only to optimization, but also to sampling. I examine the feasibility of these protocols on real devices and note that implementing such protocols should require minimal if any change to the current design of the flux qubit-based annealers by D-Wave Systems Inc. I further provide proof-of-principle numerical experiments based on quantum Monte Carlo that demonstrate simple examples of the discussed techniques.

  5. Simplified Models for LHC New Physics Searches

    SciTech Connect

    Alves, Daniele; Arkani-Hamed, Nima; Arora, Sanjay; Bai, Yang; Baumgart, Matthew; Berger, Joshua; Buckley, Matthew; Butler, Bart; Chang, Spencer; Cheng, Hsin-Chia; Cheung, Clifford; Chivukula, R.Sekhar; Cho, Won Sang; Cotta, Randy; D'Alfonso, Mariarosaria; El Hedri, Sonia; Essig, Rouven,; Evans, Jared A.; Fitzpatrick, Liam; Fox, Patrick; Franceschini, Roberto; /more authors..

    2012-06-01

    This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the 'Topologies for Early LHC Searches' workshop, held at SLAC in September of 2010, the purpose of which was to develop a set of representative models that can be used to cover all relevant phase space in experimental searches. Particular emphasis is placed on searches relevant for the first {approx} 50-500 pb{sup -1} of data and those motivated by supersymmetric models. This note largely summarizes material posted at http://lhcnewphysics.org/, which includes simplified model definitions, Monte Carlo material, and supporting contacts within the theory community. We also comment on future developments that may be useful as more data is gathered and analyzed by the experiments.

  6. NextSearch: A Search Engine for Mass Spectrometry Data against a Compact Nucleotide Exon Graph.

    PubMed

    Kim, Hyunwoo; Park, Heejin; Paek, Eunok

    2015-07-02

    Proteogenomics research has been using six-frame translation of the whole genome or amino acid exon graphs to overcome the limitations of reference protein sequence database; however, six-frame translation is not suitable for annotating genes that span over multiple exons, and amino acid exon graphs are not convenient to represent novel splice variants and exon skipping events between exons of incompatible reading frames. We propose a proteogenomic pipeline NextSearch (Nucleotide EXon-graph Transcriptome Search) that is based on a nucleotide exon graph. This pipeline consists of constructing a compact nucleotide exon graph that systematically incorporates novel splice variations and a search tool that identifies peptides by directly searching the nucleotide exon graph against tandem mass spectra. Because our exon graph stores nucleotide sequences, it can easily represent novel splice variations and exon skipping events between incompatible reading frame exons. Searching for peptide identification is performed against this nucleotide exon graph, without converting it into a protein sequence in FASTA format, achieving an order of magnitude reduction in the size of the sequence database storage. NextSearch outputs the proteome-genome/transcriptome mapping results in a general feature format (GFF) file, which can be visualized by public tools such as the UCSC Genome Browser.

  7. High Frontier: The Journal for Space and Missile Professionals. Volume 7, Number 4, August 2011

    DTIC Science & Technology

    2011-08-01

    the director of national intelligence (DNI). 3 See Joan Johnson-Freese and Roger Handberg, “ Searching for Policy Coherence: The DOD Space Architect as...Additionally, AF TENCAP has partnered with Stanford Re- search Institute, University of California Berkley and the Search for Extraterrestrial ... searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send

  8. Combinatorics in tensor-integral reduction

    NASA Astrophysics Data System (ADS)

    Ee, June-Haak; Jung, Dong-Won; Kim, U.-Rae; Lee, Jungil

    2017-03-01

    We illustrate a rigorous approach to express the totally symmetric isotropic tensors of arbitrary rank in the n-dimensional Euclidean space as a linear combination of products of Kronecker deltas. By making full use of the symmetries, one can greatly reduce the efforts to compute cumbersome angular integrals into straightforward combinatoric counts. This method is generalised into the cases in which such symmetries are present in subspaces. We further demonstrate the mechanism of the tensor-integral reduction that is widely used in various physics problems such as perturbative calculations of the gauge-field theory in which divergent integrals are regularised in d=4-2ɛ space-time dimensions. The main derivation is given in the n-dimensional Euclidean space. The generalisation of the result to the Minkowski space is also discussed in order to provide graduate students and researchers with techniques of tensor-integral reduction for particle physics problems.

  9. Space Science Enterprise Strategy

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The 2003 Space Science Enterprise Strategy represents the efforts of hundreds of scientists, staff, and educators, as well as collaboration with the other NASA Enterprises. It reveals the progress we have made, our plans for the near future, and our opportunity to support the Agency's Mission to "explore the universe and search for life." Space science has made spectacular advances in the recent past, from the first baby pictures of the universe to the discovery of water ice on Mars. Each new discovery impels us to ask new questions or regard old ones in new ways. How did the universe begin? How did life arise? Are we alone? These questions continue to inspire all of us to keep exploring and searching. And, as we get closer to answers, we will continue to share our findings with the science community, educators, and the public as broadly and as rapidly as possible. In this Strategy, you will find science objectives that define NASA's quest for discovery. You will also find the framework of programs, such as flight missions and ground-based research, that will enable us to achieve these objectives. This Strategy is founded on recommendations from the community, as well as lessons learned from past programs, and maps the stepping-stones to the future of space science.

  10. SUSY Searches at the Tevatron

    SciTech Connect

    Zivkovic, L.

    2011-07-01

    In this article results from supersymmetry searches at D0 and CDF are reported. Searches for third generation squarks, searches for gauginos, and searches for models with R-parity violation are described. As no signs of supersymmetry for these models are observed, the most stringent limits to date are presented.

  11. Standardization of Keyword Search Mode

    ERIC Educational Resources Information Center

    Su, Di

    2010-01-01

    In spite of its popularity, keyword search mode has not been standardized. Though information professionals are quick to adapt to various presentations of keyword search mode, novice end-users may find keyword search confusing. This article compares keyword search mode in some major reference databases and calls for standardization. (Contains 3…

  12. Product Searching with Shopping Bots.

    ERIC Educational Resources Information Center

    Rowley, Jennifer

    2000-01-01

    Using trial searches for three best-selling books, this study examined the search facilities offered by shopping bots, which support consumers with the product search and identification stage in e-shopping. Findings indicate that effectiveness of bots not only depends upon search facilities but also upon product coverage, and other added value…

  13. Face Search at Scale.

    PubMed

    Wang, Dayong; Otto, Charles; Jain, Anil K

    2016-06-20

    rsons of interest among the billions of shared photos on these websites. Despite significant progress in face recognition, searching a large collection of unconstrained face images remains a difficult problem. To address this challenge, we propose a face search system which combines a fast search procedure, coupled with a state-of-the-art commercial off the shelf (COTS) matcher, in a cascaded framework. Given a probe face, we first filter the large gallery of photos to find the top-k most similar faces using features learned by a convolutional neural network. The k retrieved candidates are re-ranked by combining similarities based on deep features and those output by the COTS matcher. We evaluate the proposed face search system on a gallery containing 80 million web-downloaded face images. Experimental results demonstrate that while the deep features perform worse than the COTS matcher on a mugshot dataset (93.7% vs. 98.6% TAR@FAR of 0.01%), fusing the deep features with the COTS matcher improves the overall performance (99.5% TAR@FAR of 0.01%). This shows that the learned deep features provide complementary information over representations used in state-of-the-art face matchers. On the unconstrained face image benchmarks, the performance of the learned deep features is competitive with reported accuracies. LFW database: 98.20% accuracy under the standard protocol and 88.03% TAR@FAR of 0.1% under the BLUFR protocol; IJB-A benchmark: 51.0% TAR@FAR of 0.1% (verification), rank 1 retrieval of 82.2% (closed-set search), 61.5% FNIR@FAR of 1% (open-set search). The proposed face search system offers an excellent trade-off between accuracy and scalability on galleries with millions of images. Additionally, in a face search experiment involving photos of the Tsarnaev brothers, convicted of the Boston Marathon bombing, the proposed cascade face search system could find the younger brother's (Dzhokhar Tsarnaev) photo at rank 1 in 1 second on a 5M gallery and at rank 8 in 7

  14. Space Shuttle.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    The plans for utilizing reusable space shuttles which could replace almost all present expendable launch vehicles are briefly described. Many illustrations are included showing the artists' concepts of various configurations proposed for space shuttles. (PR)

  15. Space Basics

    NASA Technical Reports Server (NTRS)

    Herbert, Dexter (Editor)

    1991-01-01

    In this education video series, 'Liftoff to Learning', astronauts (Bruce Melnick, Thomas Akers, William Shepherd, Robert Cabana, and Richard Richards) describe the historical beginnings of space exploration from the time of Robert H. Goddard (considered the Father of Rocketry), who, in 1929, invented the first propellant rocket, the prototype of modern liquid propellant rockets, up to the modern Space Shuttles. The questions - where is space, what is space, and how do astronauts get to, stay in, and come back from space are answered through historical footage, computer graphics, and animation. The space environment effects, temperature effects, and gravitational effects on the launching, orbiting, and descent of the Shuttles are discussed. Included is historical still photos and film footage of past space programs and space vehicles.

  16. Space medicine

    NASA Technical Reports Server (NTRS)

    Johnson, P. C., Jr.

    1984-01-01

    The medical aspects of space flight are briefly discussed. The problems of space adaptation syndrome, commonly known as space sickness, are described, and its cause is shown. The adaptation of the cardiovascular system to weightlessness, the problems of radiation in space, atrophy of bones and muscles, and loss of blood volume are addressed. The difficulties associated with the reexperience of gravity on return to earth are briefly considered.

  17. Space Operations

    DTIC Science & Technology

    2013-05-29

    as the Solar Heliospheric Observatory —a joint European Space Agency-NASA mission) (Ka) was launched in December 1995 and NASA’s Advanced Composition...Command, United States Central Command, United States European Command, and others. The US has missile defense cooperative programs with a number of...Therefore, civilian space agencies have often taken the leadership role for space. Agencies such as the European Space Agency, the United Kingdom

  18. Software-Defined Radio for Space-to-Space Communications

    NASA Technical Reports Server (NTRS)

    Fisher, Ken; Jih, Cindy; Moore, Michael S.; Price, Jeremy C.; Abbott, Ben A.; Fritz, Justin A.

    2011-01-01

    A paper describes the Space- to-Space Communications System (SSCS) Software- Defined Radio (SDR) research project to determine the most appropriate method for creating flexible and reconfigurable radios to implement wireless communications channels for space vehicles so that fewer radios are required, and commonality in hardware and software architecture can be leveraged for future missions. The ability to reconfigure the SDR through software enables one radio platform to be reconfigured to interoperate with many different waveforms. This means a reduction in the number of physical radio platforms necessary to support a space mission s communication requirements, thus decreasing the total size, weight, and power needed for a mission.

  19. Enhanced Text Spacing Improves Reading Performance in Individuals with Macular Disease

    PubMed Central

    Blackmore-Wright, Sally; Georgeson, Mark A.; Anderson, Stephen J.

    2013-01-01

    The search by many investigators for a solution to the reading problems encountered by individuals with no central vision has been long and, to date, not very fruitful. Most textual manipulations, including font size, have led to only modest gains in reading speed. Previous work on spatial integrative properties of peripheral retina suggests that ‘visual crowding’ may be a major factor contributing to inefficient reading. Crowding refers to the fact that juxtaposed targets viewed eccentrically may be difficult to identify. The purpose of this study was to assess the combined effects of line spacing and word spacing on the ability of individuals with age-related macular degeneration (ARMD) to read short passages of text that were printed with either high (87.5%) or low contrast (17.5%) letters. Low contrast text was used to avoid potential ceiling effects and to mimic a possible reduction in letter contrast with light scatter from media opacities. For both low and high contrast text, the fastest reading speeds we measured were for passages of text with double line and double word spacing. In comparison with standard single spacing, double word/line spacing increased reading speed by approximately 26% with high contrast text (p < 0.001), and by 46% with low contrast text (p < 0.001). In addition, double line/word spacing more than halved the number of reading errors obtained with single spaced text. We compare our results with previous reading studies on ARMD patients, and conclude that crowding is detrimental to reading and that its effects can be reduced with enhanced text spacing. Spacing is particularly important when the contrast of the text is reduced, as may occur with intraocular light scatter or poor viewing conditions. We recommend that macular disease patients should employ double line spacing and double-character word spacing to maximize their reading efficiency. PMID:24244676

  20. Solving Problems Reductively

    ERIC Educational Resources Information Center

    Armoni, Michal; Gal-Ezer, Judith; Tirosh, Dina

    2005-01-01

    Solving problems by reduction is an important issue in mathematics and science education in general (both in high school and in college or university) and particularly in computer science education. Developing reductive thinking patterns is an important goal in any scientific discipline, yet reduction is not an easy subject to cope with. Still,…

  1. Space Battery

    DTIC Science & Technology

    2008-06-13

    Space Command SPACE AND MISSILE SYSTEMS CENTER STANDARD SPACE BATTERY APPROVED FOR PUBLIC RELEASE ...person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control ... release , distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

  2. Space Law

    NASA Astrophysics Data System (ADS)

    Hermida, Julian

    2006-01-01

    This chapter examines the salient characteristics of Space Law. It analyzes the origins and evolution of Space Law, its main international principles, and some current topics of interest to the scientific community: the delimitation of airspace and outer space, intellectual property, and criminal responsibility.

  3. Constructing Space

    NASA Astrophysics Data System (ADS)

    Henderson, Austin

    This chapter chronicles the growth of the author's understanding of Media Space through his 20-year experience with coupling spaces, using video. It is a “technology-first” understanding of the construction of space. Key ideas from research studies and practice are presented, and contrasts with other genres of communication are made. The implications for distributed collaboration are explored.

  4. Fluidic Injection for Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda

    2010-01-01

    Investigations into fluidic injection for jet noise reduction began over 50 years ago. Studies have included water and air injection for the reduction of noise in scale model jets and jet engines and water injection for the reduction of excess overpressures on the Space Shuttle at lift-off. Injection systems have included high pressure microjets as well as larger scale injectors operating at pressures that can be achieved in real jet engines. An historical perspective highlighting noise reduction potential is presented for injection concepts investigated over the last 50 years. Results from recent investigations conducted at NASA are presented for supersonic and subsonic dual-stream jets. The noise reduction benefits achieved through fluidic contouring using an azimuthally controlled nozzle will be discussed.

  5. Flavor in heavy neutrino searches at the LHC

    NASA Astrophysics Data System (ADS)

    Aguilar-Saavedra, J. A.; Deppisch, F.; Kittel, O.; Valle, J. W. F.

    2012-05-01

    Heavy neutrinos at the TeV scale have been searched for at the LHC in the context of left-right models, under the assumption that they couple to the electron, the muon, or both. We show that current searches are also sensitive to heavy neutrinos coupling predominantly to the tau lepton, and present limits can significantly constrain the parameter space of general flavor mixing.

  6. Searches for Charginos and Neutralinos with the D0 Detector

    SciTech Connect

    Adams, T.; /Florida State U.

    2009-10-01

    Within the framework of supersymmetry, charginos and/or neutralinos are often the preferred topics of searches for experimental evidence. This is due to the facts that in much of parameter space they are the lightest supersymmetric partners and they offer unique final states to separate from standard model backgrounds. The D0 experiment has performed several recent searches including the traditional trilepton final state and a decay chain involving dark photons.

  7. Model Justified Search Algorithms for Scheduling Under Uncertainty

    DTIC Science & Technology

    2008-07-25

    Barbulcscu, Jean-Paul Watson , L. Darrell Whitlcy, and Adcle E. Howe. Scheduling space-ground communications for the air force satellite control network. J...searching and start again. DIM ACS Series in Discrete Math and Theoretical Computer Science, 26:437-453, October 1993. [9] Emma Hart, Peter Ross, and...Operations Research, 47:65-74, 1990. [19] Jean-Paul Watson . Empirical Modeling and Analysis of Local Search Algorithms for the Job-Shop Scheduling

  8. Search for Gluonic Excitations

    SciTech Connect

    Eugenio, Paul

    2007-10-26

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenological models for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  9. Search for Gluonic Excitations

    SciTech Connect

    Paul Eugenio

    2007-10-01

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenological models for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  10. Searching for excellence

    NASA Astrophysics Data System (ADS)

    Yager, Robert E.

    Visits to six school districts which were identified by the National Science Teachers Association's Search for Excellence program were made during 1983 by teams of 17 researchers. The reports were analyzed in search for common characteristics that can explain the requirements necessary for excellent science programs. The results indicate that creative ideas, administrative and community involvement, local ownership and pride, and well-developed in-service programs and implementation strategies are vital. Exceptional teachers with boundless energies also seem to exist where exemplary science programs are found.

  11. Searching with iterated maps

    PubMed Central

    Elser, V.; Rankenburg, I.; Thibault, P.

    2007-01-01

    In many problems that require extensive searching, the solution can be described as satisfying two competing constraints, where satisfying each independently does not pose a challenge. As an alternative to tree-based and stochastic searching, for these problems we propose using an iterated map built from the projections to the two constraint sets. Algorithms of this kind have been the method of choice in a large variety of signal-processing applications; we show here that the scope of these algorithms is surprisingly broad, with applications as diverse as protein folding and Sudoku. PMID:17202267

  12. Search for glueballs

    SciTech Connect

    Toki, W.

    1997-06-01

    In these Summer School lectures, the author reviews the results of recent glueball searches. He begins with a brief review of glueball phenomenology and meson spectroscopy, including a discussion of resonance behavior. The results on the f{sub o}(1500) and f{sub J}(1700) resonances from proton-antiproton experiments and radiative J/{Psi} decays are discussed. Finally, {pi}{pi} and {eta}{pi} studies from D{sub s} decays and exotic meson searches are reviewed. 46 refs., 40 figs.

  13. Critically damped quantum search.

    PubMed

    Mizel, Ari

    2009-04-17

    Although measurement and unitary processes can accomplish any quantum evolution in principle, thinking in terms of dissipation and damping can be powerful. We propose a modification of Grover's algorithm in which the idea of damping plays a natural role. Remarkably, we find that there is a critical damping value that divides between the quantum O(sqrt[N]) and classical O(N) search regimes. In addition, by allowing the damping to vary in a fashion we describe, one obtains a fixed-point quantum search algorithm in which ignorance of the number of targets increases the number of oracle queries only by a factor of 1.5.

  14. Space applications instrumentation systems

    NASA Technical Reports Server (NTRS)

    Minzner, R. A.; Oberholtzer, J. D.

    1972-01-01

    A compendium of resumes of 158 instrument systems or experiments, of particular interest to space applications, is presented. Each resume exists in a standardized format, permitting entries for 26 administrative items and 39 scientific or engineering items. The resumes are organized into forty groups determined by the forty spacecraft with which the instruments are associated. The resumes are followed by six different cross indexes, each organized alphabetically according to one of the following catagories: instrument name, acronym, name of principal investigator, name of organization employing the principal investigator, assigned experiment number, and spacecraft name. The resumes are associated with a computerized instrument resume search and retrieval system.

  15. Searching for Primordial Antimatter

    NASA Astrophysics Data System (ADS)

    2008-10-01

    Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - leftover from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult. Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2. According to the Big Bang model, the Universe was awash in particles of both matter and antimatter shortly after the Big Bang. Most of this material annihilated, but because there was slightly more matter than antimatter - less than one part per billion - only matter was left behind, at least in the local Universe. Trace amounts of antimatter are believed to be produced by powerful phenomena such as relativistic jets powered by black holes and pulsars, but no evidence has yet been found for antimatter remaining from the infant Universe. How could any primordial antimatter have survived? Just after the Big Bang there was believed to be an extraordinary period, called inflation, when the Universe expanded exponentially in just a fraction of a second. "If clumps of matter and antimatter existed next to each other before inflation, they may now be separated by more than the scale of the observable Universe, so we would never see them meet," said Gary Steigman of The Ohio State University, who conducted the study. "But, they might be separated on smaller scales, such as those of superclusters or clusters, which is a much more interesting possibility." X-rayChandra X-ray Image In that case, collisions between two galaxy clusters, the largest gravitationally-bound structures in the Universe, might show evidence for antimatter. X-ray emission shows how much hot

  16. Minimal Krylov Subspaces for Dimension Reduction

    DTIC Science & Technology

    2013-01-01

    Berry, Z. Drmac, and E.R. Jessup . Matrices, vector spaces, and information retrieval. SIAM review, 41(2):335–362, 1999. [8] M.W. Berry, S.T. Dumais... Information Processing Systems 14: Proceeding of the 2001 Conference, pages 849–856. [55] C.C. Paige. The computation of eigenvalues and eigenvectors of very... information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and

  17. Searching for life in the universe: lessons from the earth.

    PubMed

    Nealson, K H

    2001-12-01

    Space programs will soon allow us to search for life in situ on Mars and to return samples for analysis. A major focal point is to search for evidence of present or past life in these samples, evidence that, if found, would have far-reaching consequences for both science and religion. A search strategy will consider the entire gamut of life on our own planet, using that information to frame a search that would recognize life even if it were fundamentally different from that we know on Earth. We discuss here how the lessons learned from the study of life on Earth can be used to allow us to develop a general strategy for the search for life in the Universe.

  18. Searching for life in the universe: lessons from the earth

    NASA Technical Reports Server (NTRS)

    Nealson, K. H.

    2001-01-01

    Space programs will soon allow us to search for life in situ on Mars and to return samples for analysis. A major focal point is to search for evidence of present or past life in these samples, evidence that, if found, would have far-reaching consequences for both science and religion. A search strategy will consider the entire gamut of life on our own planet, using that information to frame a search that would recognize life even if it were fundamentally different from that we know on Earth. We discuss here how the lessons learned from the study of life on Earth can be used to allow us to develop a general strategy for the search for life in the Universe.

  19. The modern trends in space electromagnetic instrumentation

    NASA Astrophysics Data System (ADS)

    Korepanov, V.

    The future trends of the experimental plasma physical development in outer space demands more and more exact and sophisticated scientific instrumentation. Moreover, the situation is complicated by constant reducing of financial support of scientific research, even in leading countries. This resulted in the development of mini, micro and nanosatellites with low price and short preparation time. Consequently, it provoked the creation of new generation of scientific instruments with reduced weight and power consumption but increased level of metrological parameters. The recent state of the development of electromagnetic (EM) sensors for microsatellites is reported. The set of EM sensors produced at LCISR includes following devices. Flux-gate magnetometers (FGM). The reduction of new of satellite versions FGM weight as well as power consumption was achieved not only due to the use of new electronic components but also because the development of new operation modes. To this the scientific and technological study allowed to decrease FGM noise and now typical figure is about 10 picotesla rms at 1 Hz and the record one is below 1 picotesla. Also because of satellite weight reduction the possibility was studied to use FGM only for satellite attitude control. The magnetic orientation and stabilization system was developed and new FGM for orientation was created. It uses industrial components and special measures are taken to increase its reliability. Search-coil magnetometers (SCM). The super-light version of SCM was created as the result of intensive scientific and technological research. These new SCMs can have about six decades operational frequency band noise with upper limit ~ 1 MHz and noise level of few femtotesla with total weight about 75 grams. Electric probes (EP). The study of operation condition of EP immersed in space plasma allowed to find the possibilities to decrease the EP weight conserving the same noise factor. Two types of EP operating from DC and from 0

  20. Space Launch System Accelerated Booster Development Cycle

    NASA Technical Reports Server (NTRS)

    Arockiam, Nicole; Whittecar, William; Edwards, Stephen

    2012-01-01

    With the retirement of the Space Shuttle, NASA is seeking to reinvigorate the national space program and recapture the public s interest in human space exploration by developing missions to the Moon, near-earth asteroids, Lagrange points, Mars, and beyond. The would-be successor to the Space Shuttle, NASA s Constellation Program, planned to take humans back to the Moon by 2020, but due to budgetary constraints was cancelled in 2010 in search of a more "affordable, sustainable, and realistic" concept2. Following a number of studies, the much anticipated Space Launch System (SLS) was unveiled in September of 2011. The SLS core architecture consists of a cryogenic first stage with five Space Shuttle Main Engines (SSMEs), and a cryogenic second stage using a new J-2X engine3. The baseline configuration employs two 5-segment solid rocket boosters to achieve a 70 metric ton payload capability, but a new, more capable booster system will be required to attain the goal of 130 metric tons to orbit. To this end, NASA s Marshall Space Flight Center recently released a NASA Research Announcement (NRA) entitled "Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction." The increased emphasis on affordability is evident in the language used in the NRA, which is focused on risk reduction "leading to an affordable Advanced Booster that meets the evolved capabilities of SLS" and "enabling competition" to "enhance SLS affordability. The purpose of the work presented in this paper is to perform an independent assessment of the elements that make up an affordable and realistic path forward for the SLS booster system, utilizing advanced design methods and technology evaluation techniques. The goal is to identify elements that will enable a more sustainable development program by exploring the trade space of heavy lift booster systems and focusing on affordability, operability, and reliability at the system and subsystem levels5. For this study